A 910/9-75-007


   1975
                        LOGGING ROADS AND


           PROTECTION OF WATER QUALITY
                        U,S. ENVIRONMENTAL PROTECTION AGENCY

                                           REGION X

                                       WATER DJVJSION
                                       1200 SIXTH

                                  SiATTLE, WASHINGTON

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                                               LLJ
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This document is available to the public through the
National Technical Information Service, Springfield, Virginia  22161

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                                                      EPA  910/9-75-007

                                                      MARCH 1975
            LOGGING ROADS AND PROTECTION  OF WATER QUALITY
                              PREPARED BY:
PART I; PART  II, pp 273-300

       EPA REGION X
      WATER DIVISION

     1200 Sixth Avenue
 Seattle, Washington  98101
    PART II,  pp 91-272

ARNOLD, ARNOLD AND ASSOCIATES
      1216 Pine Street

            and

       DAMES AND MOORE
  Seattle,  Washington  98101

            for

       EPA  REGION   X
                                                  ix-onmtuvrl Protection'
                                               230 Sc.--.. ,; i^ja^bcrn Street
                                               Chicago, Illinois  606QH

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The Environmental Protection Agency, Region X, has reviewed




this report and approved it for publication.  Mention of




trade names or commercial products does not constitute




endorsement or recommendation for use.
 ENVIRONMENTAL PROTECTION AGENCY




                              2

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                            TABLE OF CONTENTS

                                                                 Page

List of Tables	   7
List of Figures	   g

INTRODUCTION  	   11
   Purpose	   11
   Scope	   13

PART I:   OVERVIEW

   FOREST LANDS OF REGION X	   19
      PHYSIOGRAPHY AND SOILS	   19
         Terrain	   19
         General Physiographic and Soil Variations 	   23
      GEOLOGY	   35
      CLIMATE	   38
      FOREST STATISTICS  	   43
         Forest Ownership	,	   43
         Logging Road Activity	   43
         Logging Road Costs	   47

   EFFECT OF LOGGING ROADS ON WATER QUALITY	   51
      GENERAL WATER QUALITY PROBLEMS AND PROTECTION CONCEPTS . .   52
         Logging Road Sediment	   53
            water quality problem areas	   55
      DETERMINING POTENTIAL FOR POLLUTION FROM LOGGING ROADS . .   62
         Other Use Classifications	   63
            standards	   63
            basin plans	   65
      WATER QUALITY RISK ANALYSIS	   66

   SURVEILLANCE AND MONITORING 	   71
      MONITORING NONPOINT SOURCES OF POLLUTION 	   71
         Parameters and Frequency  	   75
            monitoring approaches  	   76
            parameters	   78
         Use of Water Quality Data	   82

   REFERENCES	   85

PART II:   DESIGN CRITERIA

   INTRODUCTION  	   91
      SUMMARY AND CONCLUSIONS  	   96
      RECOMMENDATIONS	   99

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                              CONTENTS
                                                               Page

ROUTE PLANNING AND RECONNAISSANCE	       101
   ROUTE PLANNING	'.      103
      Management-Engineering Dialogue 	   103
      Engineer's Assessment of Management's Decision  ....   105
         state of the art techniques	   106
         roads and harvest method relationships	   Ill
      Conclusions	      113
   ROUTE RECONNAISSANCE	'..'.'   113
      Factors Affecting Surface Erosion 	   115
      Surface Erosion and Mass Wasting Considerations ....   118
         aids	   120
          aerial photographs  	   120
          topographic maps	   122
          soil surveys	   122
          geologic maps   	   124
          other aids	   124
         field reconnaissance	   124
          surface erosion 	   126
          mass wasting	   133
      Civil and Forest Engineering	   136
         harvest method	   136
         existing road audit	   137
         route placement	   138
         field survey information 	   142
   ECONOMIC EVALUATIONS 	   145
      Cost Analysis	   145
      Economic Justification  	   150

DESIGN	   153
   ROADWAY	   154
      Horizontal and Vertical Alignment 	   155
      Road Prism	   156
         excavation	   156
         embankment	   158
         balanced construction  	   160
      Road Surfacing	   160
      Buffer Strips 	   162
   SLOPE STABILIZATION	   167
      Surface Erosion 	   167
         seeding and planting	   167
          revegetation objectives 	   168
          seed mixtures	   169
          planting	   171
          techniques used in establishing plants  	   171
          when to seed or plant	   172
          fertilizers	   173
          mulching	

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                           CONTENTS

                                                            Page

      mulches and chemical soil stabilizers	    175
       need for slope protection during vegetation
         establishment	    177
       performance of various mulches and chemical
         soil stabilizers	    180
      mechanical treatment 	    188
       diversions or terraces  	    189
       serrations	•	    189
       roughness and scarification	    191
   Mass Wasting	    192
      retaining walls  	    195
      bulkheads	    196
      reinforced earth 	    196
      rock rubble facing	    197
      lowering groundwater levels  	    197
      deep rooted vegetation 	    198
      fill placement	    199
DRAINAGE DESIGN  	    200
   Ditches and Berms	    200
      size and placement	    201
      ditch profiles	    205
      ditch outlets	    207
      sloped roadway alternate to roadside ditches ....    207
      rock sub-drain alternate to roadside ditches ....    211
   Culverts	    212
      sizing culverts  	    217
      design aspects of culvert installation 	    220
       roadway culverts  	    220
       stream culverts 	    221
   Water Course Crossings  	    223
      sediment features of stream crossing design  ....    224
      stream crossing methods  	    227
       fords	    227
       culverts	    228
       bridges	    229
   Culvert Outlet Treatments 	    232
   Hydrology	    241
      logging and roadbuilding 	    241
      subsurface water considerations  	    243
      forest location  	    244
CONSTRUCTION SPECIFICATIONS  	    246
   Standard Specifications 	    247
   Special Provisions  	    248
   Conclusions	    250

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                                 CONTENTS
                                                                   Page

   CONSTRUCTION TECHNIQUES 	   251
      CLEARING AND GRUBBING  	   252
      EARTHWORK	   253
      DRAINAGE	   256
         Drainage During Construction  	   256
         Drainage Construction 	   257
      CONSTRUCTION EQUIPMENT 	   259

   MAINTENANCE	"	   263
      DRAINAGE SYSTEM	   265
         Culverts and Ditches	   265
         Cut and Embankment Slopes	   267
      ROAD SURFACE	   267
      REMEDIAL MEASURES FOR SLIDES	   269
         Removing Slide Debris 	   270
         Wasting Slide Debris  	   271
         Relocation vs Correction   	   271
         Failure Mechanism Investigation 	   272
      INTERMITTENT AND SHORT TERM USE	   273
         Intermittent Use	   274
            roadway	   275
            stream channel crossings 	   276
             pre-planned crossing   	   278
             existing crossings  .   . .	   279
         Short Term Use	   281
            roadway	   281
            channel crossings  	   284
      ROAD MAINTENANCE CHEMICALS	   285
         Dust Palliatives	   285
            pollution from oil based dust palliatives	   287
            control of pollution from oil dust palliatives .  .  .   289
             oil spills	   290
             oontrol practices 	   291
         Other Chemicals	   293
            salts	   293
            pulp wastes	   297
            others	   299

REFERENCES	   301

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                             LIST OF TABLES
Table                                                            Page

  1        Mean Monthly and Annual Variability                     40
           of Climatic Conditions

  2        Construction and Reconstruction Costs                   48
           of Logging Roads

  3        Comparison of Some Stream Classification                64
           Systems

  4        Guide for Placing Common Soil and Geologic             128
           Types into Erosion Classes

  5        Unified Soil Classification                            129

  6        Siuslaw National Forest-Plant Indicators               144

  7        Comparison of Annual Road Costs Per Mile,               147
           10,000 Vehicles Per Annum (VPA)

  8        Comparison of Annual Road Costs Per Mile for           148
           20,000 and 40,000 Vehicles Per Annum (VPA)

  9        Comparison of Single-lane Versus Double-lane           149
           Costs for Three Different Vehicle-Per-Annum
           (VPA) Categories

  10       Protective - Strip Widths                              166

  11       Comparison of Cumulative Erosion From Treated          179
           Plots On a Steep, Newly Constructed Road Fill

  12       Erosion Control and Vegetation Establishment           182
           Effectiveness of Various Mulches

  13       Maximum Permissible Velocities in Erodible             202
           Channels, Based on Uniform Flow in Continuously
           Wet, Aged Channels

  14       Cross-drain Spacing                                    209

  15       Settling Velocities for Various Particle Sizes         240
           10.00 mm to 0.00001 mm

  16       Chemicals Used on Logging Roads                        286


                                    7

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                             LIST OF FIGURES


Figure                                                            Page

  1        Map of Region X                                          12

  2        Relatively Undissected Slopes                            21

  3        Highly Dissected Slopes                                  21

  4        Examples of Landslide, Slump Indicators                  24

  5        Physiographic Provinces                                  25

  6        Soils Developed in Granitic Rocks                        28
           with Stability Problems

  7        Surface Soil Erosion in Batholith                        28
           Area of Idaho

  8        Sedimentation from Logging Road in                       31
           Cascade Province

  9        Continual Road Instability in Pacific                    31
           Border Province

  10       Mass Failure Associated with Logging                     33
           Roads in Pacific Border Province

  11       Mean Annual Precipitation                                41

  12       Ownership Distribution of Commerical                     44
           Forest Land, All States, Region X

  13       Ownership Distribution of Commercial                     45
           Forest Land by States Region X

  14       Erosion from Long Water Transport                        58

  15       Culvert Outlets                                          59

  16       First Year Damage to Logging Roads                       60

  17       Season of Use Damage                                     60

  18       Water Quality Monitoring Approach                        79
           for Cumulative Impacts

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Figure                                                             Pa€e

  19       Workload Analysis-Geotechnical  Investigations           109
           for Timber Sale Roads-Siuslaw National Forest

  20       Sediment Movement Down- slope from Shoulders             165
           of Logging Roads
  21       Soil Losses from a 35 Foot Long Slope

  22       Ditch Water Surf ace -Road Subgrade                        203

  23       Minimum Interceptor Ditch Size                           204

  24       Berm                                                     204

  25       Ditch Placement                                          206

  26       Ditch Outlet Near Stream                                 206

  27       Rock Sub -drain                                           211

  28       Ditch Inlet Structure                                    213

  29       Ditch Inlet Structure with Catch Basin                   214

  30       Upstream Embankment Face Treatment                       222

  31       Gabion Ford                                              228

  32       Culvert Outlets                                          234

  33       Culvert Outlet Near Stream                               235

  34       Pipe Channel Detail                                      235

  35       Rock Dike                                                236

  36       Alternate Pipe Channel Detail                            236

  37       Gravel Filled Crib Wall                                  238

  38       Energy Dissipating Silo                                  239

  39       Culvert Outlet to Sediment Pond                          239

  40       Alternate Waste Site                                     255

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Figure                                                            Page




  41       Kaniksu Closure                                         277




  42       Modified Culvert Removal
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                    INTRODUCTION
                              PURPOSE






     The Federal Water Pollution Control Act Amendments  of 1972, Public



Law 92-500,  set a national goal of water quality which provides for the



protection and prppagation of fish, shellfish,  and wildlife and which



provides for recreation  in and on the waters.  This goal must be achieved



by 1983.  The Act mandates that pollution caused by runoff from forest



lands, as well as other  nonpoint sources (mining, construction, agri-



culture, etc.),  be controlled in addition to the control of point



sources in order to achieve the national goal of water quality.






     This report is a state-of-the-art reference on the  protection of



water quality in planning, designing, constructing,  reconstructing,




using, and maintaining logging roads based on data collected in Region X.



It is intended to be an  aid for dealing with nonpoint  source pollution



control; and is designed to inform and assist state, federal and local



agencies; industry;  and  the general public.   The report  is specifically



intended to assist in the (1) identification of potential hazards to



water quality, and (2) selection of procedures, practices, or methods



suitable for preventing, minimizing, or correcting water pollution



problems.  It also is a  reference source to  other publications, informa-



tion and materials;  and  it provides some regional data and perspective.



Figure 1 shows the geographical boundaries of Region X.
                                 11

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            UNITED STATES
ENVIRONMENTAL PROTECTION AGENCY
             Regional Offices
r\
MAINE
 I
                             IpUERTO-
                              R 'CO
               FIGURE 1  REGION X
                     12

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     The Environmental Protection Agency has already prepared a report



entitled "Processes, Procedures and Methods to Control Pollution from




Silvicultural Activities", which was published in October, 1973.  That



report covers all forest practices and is, therefore, general in nature.



In contrast, this report deals specifically with one important aspect




of forest practices.



     "Silvicultural activities" comprises a major portion of those



forest land activities in Region X that can impact water quality.



"Silvicultural activities" is used in a broad context; and covers the



actions and results of all forest harvest, production, management and



protection systems.  Some of the categories of activities included are:



logging roads, harvesting methods, silviculture systems, residue manage-



ment, reforestation, and use of chemicals.



     Of all the types of silvicultural activities, improperly constructed



and inadequately maintained "logging roads" are conceded to be the



principal man-caused source of sediment.  Although different logging



systems have different road access requirements, all involve to some



degree the construction or reconstruction and use of logging roads.





                                  SCOPE






     "Logging Road", as used in this document, refers to truck roads



which are built or used mostly for log hauling or logging operations.



These roads are often subsequently used for the protection and manage-



ment of successive timber crops and for other forest access purposes.
                                   13

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     The text deals with a range of logging road design standards—




varying from low-speed narrow,  unsurfaced roads to moderately high




speed, rocked or paved roads.  Paved,  two-lane (or more) roads that




have design characteristics similar to or higher than secondary state




highway standards are beyond the scope of this document.




     Although logging haul roads (within the standards range described




above) are the primary focus, most of the principles and techniques




described have a wider application and can be extended to include all




other forest access roads which are similar in standard but are




constructed for different specific purposes—e.g., for mining, grazing,




recreation and fire protection—or for multi-purposes.




     It should be recognized that roads are not an independent entity




and must be considered in an overall context.  For example, in relation




to the total physical systems operating in a watershed, such factors as




the total area of land surface exposed by roads at a given time, effects




of runoff from roads on channel stability and the degree to which a




transportation system can be effectively maintained may be important.




     Another important interrelationship is that of the road to total




planning of a silvicultural activity.  For instance, from a water quality




consideration viewpoint, impacts of a total harvesting  system must be




examined—including logging methods and logging roads.  For example,




a skyline cable system might result in a low total impact, including




fewer roads.  However, individual roads might require special design




standards to accomodate the overall low impact  system.
                                     14

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     The foregoing discussion is for illustration only.  Detailed

examination of total systems' interrelationships is beyond the scope

of this report.

     Region X, excluding interior Alaska i/, served as the specific

study area for the compilation of this report.  While state-of-the-art

information was compiled primarily from within Region X, relevant data

from outside the Region was also evaluated and used as appropriate.

Information from scientists and practitioners outside the Region

indicates that most of the principles and many of the techniques in

this report will have application to a much wider area that just

Region X.  As can be noted throughout the report, an  important key

for incorporating water quality management needs into logging road

activities is the intelligent tailoring of available technology to site

specific application.  This applies irrespective of geographical

location.
-I   Two other reports should be useful for dealing with interior
     Alaska conditions:

     Lotspeich, F. B. 1971.  Environmental Guidelines for Road
     Construction in Alaska.  Alaska Water Laboratory, U.S.
     Environmental Protection Agency, College, Alaska.

     Lotspeich, F. B. and Helmers, A. E.  1974.  Environmental
     Guidelines for Development Roads in the Subarctic.National
     Environmental Research Center, U.S. Environmental Protection
     Agency, Corvallis, Oregon.
                                    15

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          PART I
Overview And Setting Of Region X

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        FOREST LANDS OF REGION X





     The information in this section describes some of the physical



features of Region X.  It is intended to facilitate Region-wide under-



standing and perspective of potential water quality degradation.



Specific principles and application are discussed in Part II  and in



cited references.




     Although significant features are discussed separately,  most of



them are not independent. They should be viewed together, and in the



context of the relationship of logging roads to the water handling and



resistance to soil movement—either surface erosion or mass movement—



characteristics of a watershed.



     It should be noted that soil movement—including mass failure—



occurs naturally.  The emphasis in this section, however, is  "man-caused"—



i.e., road related—events.






                        PHYSIOGRAPHY AND SOILS





TERRAIN






     "Terrain", as used in this report, refers to external character-



istics (features) of the land such as slope,  shape, drainage  density,



smoothness (or unevenness), slumps and slides.  The Encyclopedia of



Geomorphology (10) describes geology-terrain relationships and descrip-



tive classifications.




     This section is intended only to illustrate the importance of terrain



factors in anticipating and estimating potential impacts of logging roads.






                                19

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Discussion of specific elements,  evaluation criteria and procedures for



dealing with these factors are discussed in more detail in Part II.



     Several terrain features have been specified or implied to be



important in planning and constructing stable roadways.  Brown (l)




cites aspect, elevation and steepness of slope.  Way (2) uses topography,



drainage—including texture (number of streamcourses) and pattern—and




vegetation for terrain analysis.   Kojan, et al (3) use slope gradient,



sub-surface structure and evidence of landslides.  Other authors have



cited similar factors.




     Several terrain features consistently emerge as important indicators



which can aid in estimating the probable impact of logging roads on the



terrain and resultant impact on water quality.  These are:



     (a)  drainage density (degree to which streamcourses



          dissect the land);



     (b)  slope (gradient, length, shape,  position on the slope);



     (c)  geologic factors such as substrata fracture planes



          (not always visible externally,  but may be observable



          in landslides); and



     (d)  "hummooky" slopes.



     Generally, the more drainage that dissects the landscape, the more



acute the necessity to plan for avoiding water quality impacts in



constructing and stabilizing roads.  Figure 2 illustrates relatively



undissected ("smooth") slopes, and Figure 3 highly dissected slopes.
                                   20

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FIGURE 2  RELATIVELY UNDISSECTED SLOPES - ESPECIALLY
                   IN FOREGROUND
         FIGURE 3  HIGHLY DISSECTED SLOPES

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     Steepness and length are among the more obvious slope indicators.



Swanston and Dyrness (4), Swanston (44), Burroughs et al (5) and others



describe relationships of slope gradient to potential soil displacement.



Usually, the steeper and more sustained the slope, the greater the risk



and more frequent the occurrence.  There is no precise universal rule



that links a given slope steepness to a specific set of problems because



other factors must be considered.  For example, where the terrain is




relatively undissected and relatively stable,  road-triggered soil move-



ment problems may become acute when sustained slopes are 60 to 65 percent



(or steeper).  However, where the terrain is highly dissected and



relatively stable, impacts may become severe on slopes 40 to 45 percent



(or steeper).  If soils or geologic substrata are unstable, major impact



problems may occur on slopes of 30 percent or less.  Kojan et al (3)



reported that few debris slides occurred on slope gradients less than



50 percent.  However, they also reported an increasing incidence of



translational-rotational earth slides (deep slides associated with sub-



strata failure) on slopes steeper than 30 percent in certain rock material



types.




     Of all ownerships in Region X,  roughly 1/4 of the commercial



forest land (CFL) is on slopes steeper than 45 percent and about 1/5



is on slopes steeper than 55 percent (6).  The 45 and 55 percent figures



are arbitrary demarcations of "steepness".
                                   22

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     Kojan et al (3) state "The type and distribution of existing




landslides, both active and dormant, is the single most important




factor determining the performance and impact from roads..."  Others




have reported or stated that evidence of past mass soil movement is




an important clue for anticipating the results of man's activities on




unstable areas.  Figures 4 and 10 illustrate some examples of mass




soil movement as related to terrain, soils, geology and climate.






GENERAL  PHYSIOGRAPHIC AND SOIL  VARIATIONS






     The major physiographic areas within the Region may be divided into




areas of similar geologic structure and climate.  These provinces can be




separated into major subdivisions, (Figure 5), each subdivision having




significantly different characteristics that affect road planning, design,




construction, maintenance and use.




     Road construction, timber harvest, and many other land management




activities have an effect on soil and water resources.  It is important




to understand the effect and potential consequence relationships.  Soils




can be grouped according to similar characteristics and general condi-




tions as topography, elevation, climate, water resources and land use.




Groupings may include broad areas with similar soil characteristics.  The




objective of most groupings is to identify areas of land that are rela-




tively uniform in many important relationships.




     The general physiographic variations and soils discussion is




intended only for a broad regional perspective of soil and land character-




istics.  The optimum level of information for minimizing water quality






                                   23

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                    LANDFLOW
        ROAD TRIGGERED DEBRIS SLIDE ALONG
           A PARALLEL SUBSTRATUM PLANE

FIGURE 4  EXAMPLES OF LANDSLIDE,  SLUMP INDICATORS

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VJl
                                                                                                    PHYSIOGRAPHIC

                                                                                                      PROVINCES      {
                                                                                                                  _ -i |
                                                                                           Province Boundary


                                                                                           Sub-Province  Boundary
                                                           ASIN  AND  RANGE
                                                          FIGURE  5

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impacts from logging roads is an on-site assessment or site specific



field evaluation of proposed road locations to determine soil and




geological characteristics on a project basis.  See Section on Route



Planning and Reconnaissance, Part II.




     Various authors have divided the Region differently.  The divisions



used in Figure 5 are largely those outlined by Allison (7).  Areas




treated as subprovinces by some authors are considered provinces by



others.  However, the basic subdivisions are nearly the same.  Soils



and geologic information for this section come from several sources:



Baldwin (8), Burroughs (5), Campbell (9); several soils survey reports



for parts of the Region; and discussions and field observations with



forest land managers.




     The seven physiographic provinces that lie partly or wholly within



the Region (Figure 5):



         Northern Rocky Mountains.



         Middle Rocky Mountains.



         Columbia Intermontane.



         Basin and Range.



         Cascade Mountains.



         Pacific Border.



         Pacific Mountain System (Alaska).  I/
     ik'  Not shown in Figure 5
                                   26

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Northern Rocky Mountains Province





     The province includes parts of northeastern Washington and northern




and central Idaho.  It is characterized by high mountain ridges and deep



intermontane valleys eroded from rocks of moderately complex structure.



The irregular mountains of Central Idaho developed from erosion of



massive granite rocks.  Much of the province is submature to mature in




the geomorphic cycle.



     Logging road construction is particularly damaging in highly erodible



areas of the province, such as the 41,500 km2  (16,000 square miles) Idaho



Batholith.  The Batholith of Central Idaho consists of soils developed



in granitic materials.  These soils present erosion problems, as shown



in Figure 6.  The Batholith is characterized by steep topography and



shallow to moderately deep, coarse-textured soils overlying granitic



bedrock.  In parts of the province, the concentration of coarse sand



increases the susceptability to erosion, during road construction.



Surface soil erosion is the major problem in much of the area as shown



in Figure 7, where slopes are less than 60 percent.  Where slopes are



greater than 60 percent, mass erosion is an important problem.






Middle Rocky Mountain Province





     A part of the Middle Rocky Mountain Province extends into southern



Idaho, where northwesterly trending mountain ridges and valleys have



eroded from folded, thrust-faulted, or tilted rocks.  The valleys are
                                    27

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FIGURE 6  SOILS DEVELOPED IN GRANITIC ROCKS
          WITH STABILITY PROBLEMS
     FIGURE 7 SURFACE SOIL EROSION IN
          BATHOLITH AREA OF IDAHO
                    28

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about 1,850 meters (6,000 feet) above sea level, with ridges 600 to



1,200 meters (2,000 to 4,000 feet) higher.



     The logging road problems in the province are principally related



to mass gravity soil movements, such as slumps.  Mass failures are



a-ssociated with sedimentary deposits of sandstone, shale, siltstone,



limestone, and volcanic ash.  Surface soil erosion may also cause




water quality problems in some areas.






Columbia  Intermontane Province






     This province includes the Columbia Basin, Central Mountains,



Harney High Lava Plains, Malheur-Owyhee Upland, and Snake River Lava




Plain.



     A relatively small percentage of the province is managed for wood




fiber production.  Logging road activities are limited as compared to



the major timber producing provinces (Cascades and Pacific Border).



Steep slopes (greater than 60$) are few and are associated with



isolated basaltic buttes or canyons.  Because of the general climatic



conditions (low precipitation), water quality problems relating to



logging roads are rather localized, with surface soil erosion being the



principal problem.






Basin and Range Province






     The northern edge of the Great Basin section of the Basin and Range



Province extends into south central Oregon and into southern Idaho.  The
                                   29

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logging road conditions are generally similar to those discussed for the

Middle Rocky Mountain Province.

     The part in Oregon in contrast to Idaho is a youthful high lava

plain.  Small cinder cones are numerous in the western portion, where a

sheet of pumice from Mt. Mazama extends over a large area, 26,000 square

kilometers (more than 10,000 square miles).  This pumice sheet greatly

modifies vegetation, surface runoff, and land use.  With disturbance for

logging road construction and extensive use during the summer or dryer

seasons, the soils become very friable and susceptible to surface erosion.

Because of the relatively gentle topography in much of the area and the

moderate-to-rapid soil permeability, water quality problems due to logging

roads are localized.


Cascade Mountains Province


     The Cascades of Oregon and the southern half of Washington are a

broad upwarp composed of a basal portion of tuffs, breccias,  lavas,

mudflows,  a thick middle section of basalt, and an upper section of

andesites and basalts that form the less dissected High Cascade lava

platform.

     Soils in the province are generally weakly developed and have been

influenced by volcanic ash and pyroclastic materials.   There  is a

potential for severe surface erosion on steep slopes when the organic

layer is removed.  The problem is accentuated by the abundance of streams

and surface water and high precipitation in much of the area.  Figure 8

illustrates some of the serious water quality impacts associated with

logging roads in this province.
                                   30

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  FIGURE 8  SEDIMENTATION FROM LOGGING ROAD
               CASCADE PROVINCE
FIGURE 9  CONTINUAL ROAD INSTABILITY PACIFIC
              BORDER  PROVINCE
                     31

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Pacific Border Province






     The province includes the Klamath-Siskiyou Section, Coast Range,




Olympic Mountains, and Willamette-Cowlitz Puget Lowlands (Figure 5).



     Compared to the other provinces the Pacific Border province has some



of the most severe and continuous water quality impacts associated with



logging roads.  The major problem areas are the coastal areas of




Washington and Oregon and the Olympic Peninsula.  These areas are



characterized by high precipitation, as shown in Figure 11.  Soils are



developed in a wide range of materials, principally sedimentary deposits.



They have a variety of textures and drainage characteristics.  With the



dominance of very high rainfall and steep slopes, many of the soils,



especially those in disturbed conditions (some undisturbed), have a high



degree of continual instability as shown in Figure 9.




     Mass soil failures associated with logging roads as shown in Figure 10,



occur in the province.  The water quality impacts are particularly acute



in steep headwall areas of drainages.  These drainages are the principal



tributaries to many of the major streams and water bodies of the area.



A more detailed discussion of the nature,  source and extent of the erosion



problem and recommended procedures for dealing with this problem are



discussed by Burroughs (5), Brown (l), and Dyrness (35).






Pacific Mountain System






     This coastal province extends from the southern boundary of Alaska



to the Aleutian Islands (41).  However, the following discussion is
                                  32

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FIGURE 10  MASS FAILURE ASSOCIATED WITH LOGGING ROADS
             IN PACIFIC BORDER PROVINCE


  Photograph taken from road edge looking downslope
                         33

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limited to the southeast portion of this province, from the southern



border to Yakutat Bay (42).




     The southeast area is composed of a mainland strip and a wide




belt of rugged islands with summits generally 750 to 1,050 meters



(2,500 to 3,500 feet) in elevation.  Most of the mainland strip is



deeply indented by fiords.  Its peaks rise to about 3,050 meters




(10,000 feet) along the Canadian Border.  Many of the inter-island water-



ways and major fiords and streams occupy long linear depressions, most



prominent of which is Chatham Strait, a deep trench 6 to 24 kilometers



(4 to 15 miles) in width and some 320 kilometers (200 miles) long.



     Soils on the broad coastal plain at Yakutat are shallow to deep,



gravelly, sandy to silty loams in association with moss peats of variable



thickness and depth.  Small amounts of waterlaid sands, gravels,  and silts



occupy broad stream channels and low areas adjoining the fiords.   Logging



road limitations are slight on well drained soils, becoming moderate to



severe with increasing wetness.



     Soils on the moraines and foot slopes bordering the plain are shallow,



stony and gravelly loams with finer sediments in the vicinity of fiords



and peat deposits in depressions.  Limitations for these soils are moderate



to severe for logging roads,  depending on slope.  Soils of steep  hills



and low mountain slopes are very gravelly silt loams over shallow bedrock



in association with similar soils having a firm subsoil and occupying



low moraines.  Peat deposits occupy depressions extensively throughout



these soils.   Limitations are moderate to severe for use of these soils



for road construction (43).





                                   34

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                              GEOLOGY






     Geology as it relates to the physical character and areal




distribution of various rock types plays a major role in controlling



or effecting the quality of water in streams and rivers.  Geology governs



the character of soils as rock formations are the parent material for



most soils.  The erodibility of many sedimentary rock formations is



directly related to the degree or amount of cementation.  Fine-grained



unconsolidated formations can "be easily eroded while tightly cemented



sediments may be very resistant to erosion.



     The physical properties of the rock formations also play an important



role in the quantity and time distribution of runoff from a watershed.



Rock formations having high porosity and permeability will adsorb water



during wet seasons and discharge it to streams throughout the year.  The



Metolius River in Oregon is an outstanding example of a large stream



being maintained at an almost uniform flow throughout the year by the



porous and permeable rocks of the area.  Conversely, rocks of low porosity



and permeability do not have the capability of adsorbing and transmitting



large quantities of water.  Consequently, streams heading in areas under-



lain with these rocks exhibit a" tremendous fluctuation in flow from season



to season and in some cases may respond rapidly to almost every heavy



rainstorm.  The general geologic character of a drainage basin can



generally be interpreted by how a stream draining the area responds to



climatic changes.
                                   35

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     Construction within a drainage basin may not measurably effect the



total loading of sediment being transported by a stream, but it can



change the seasonal distribution of the load.  A small amount of sediment



washed or pushed into a stream in the late shimmer or early fall months



may have a marked effect on water quality, while a similar increase in



load during high water periods may be undetectable.




     Rock types, as they relate to water quality effects, can be divided



into three principal groups:



     1.  Volcanic Rock




     2.  Intrusive and Metamorphic Rocks



     3.  Sedimentary including Pyroclastic Rocks



     Volcanic rocks are very common to many forested areas of the Pacific



Northwest.  They include the basaltic and andesitic  lava flows that



underlie a large part of the Cascade Mountain Range  in Oregon and in the



southern part of Washington.  They also underlie the Blue Mountains in



Southeastern Washington and Northeastern Oregon.



     Most volcanic rocks are jointed which provides  for the adsorption



and storage of water.  Permeable lava flows and permeable contact zones



between flows generally provide for the movement of  water through the



formation.  Volcanic rocks are the source of many of the very large



springs in the Region.



     In some of the more humid areas of the Region the older volcanic rocks



have been weathered into red lateritic clays.  When  disturbed or naturally



eroded, these weathered lavas can create very turbid water.  In the dryer
                                  36

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areas of the Eegion or in areas underlain with younger volcanic rocks,



as the High Cascade area in Oregon, the volcanic rocks are relatively



unweathered and are resistant to erosion and generally contribute to




excellent water quality.



     Metamorphic and intrusive rocks which include gneiss, granite and



grandiorite are common to the Northern Cascades in Washington, North



Central and Northeastern Washington, much of central Idaho, and the



Wallowa and Siskiyou Mountains in Oregon.  These rocks have relatively



few joints or cracks and generally do not adsorb or transmit large quanti-



ties of water.  Streams draining unweathered rocks of this group gener-



ally have large seasonal fluctuation and respond rapidly to rainstorms.



Intrusive rocks in the early stage of weathering break down into a sandy



material composed chiefly of individual crystals of feldspar.  Continued




weathering produces kaolinitic clay that can be easily eroded when



disturbed.



     Sedimentary rocks which are composed of fragments of other rock



types exhibit a very large range in porosity and permeability, ranging



from an almost impermeable glacial till to very permeable open-work



gravel formations that are almost void of sand and silt fractions.



A large part of the Coast Range in Oregon, the Willapa Hills in



Washington and most of southeastern Alaska are underlain by sedimentary



rocks.  Because of the widespread occurrence of volcanism in the Region,



a very large part of the sedimentary rocks are composed of volcanic ejecta



consisting of pumice and ash.  These pyroclastic materials are composed
                                   37

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chiefly of volcanic glass, weathered to bentonitic clays.  These clays



are easily eroded, and can create widespread turbidity problems and also



serious engineering problems from slides in road construction.  The Corps



of Engineers in studying the water turbidity problems in the Rogue River




Basin of Oregon in connection with the construction of the Lost Creek



Dam found that the tributary stream basins underlain with pyroclastic



sediments were the chief areas contributing suspended material to that



river system.




     Detailed geologic maps should be' a prerequisite to any large develop-



ment that will disturb the landscape.  Unfortunately, most geologic maps



do not have the details necessary to identify rock permeabilities, degree



of weathering, erodibility, and such hazards to construction as the



probability of slides or slumping.  As all of these factors can play an



important role in subsequent water quality effects arising from road



construction and use, a geologic evaluation of the proposed construction



area should be a part of the design of any project.  Equally important



however is the subsequent use of a geologist to evaluate conditions



encountered during construction.





                               CLIMATE






     Climate considerations are essential for logging road planning,



design, construction, maintenance and use.  Climate, as with soils,



terrain and other physical considerations, varies widely throughout the



Region.  It is apparent from this wide variability, that an understanding




of site specific conditions is essential to minimize impacts from logging




                                    38

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roads.  Pollution from sediment, deicers and oils used in road




maintenance are greatly influenced by climate.




     The wide diversity of precipitation and temperatures for January,




July, and annually for dominant forested areas is shown by the mean




monthly data in Table 1 for Seattle near the Pacific Coast; Meacham,




Oregon and Potlatch, Idaho inland; and Juneau in Southeastern Alaska.




Figure 11 illustrates the general regional pattern (excluding Alaska)




of mean annual precipitation.  More detail maps are essential for




project planning.  These maps are available from the U.S. Weather




Bureau.






PACIFIC NORTHWEST






     Precipitation (including both rain and snow) generally increases from




south to north, from east to west, and from valleys to mountains.  The




general movement of storms is easterly from the Pacific Ocean.  Annual




precipitation varies from 180 centimeters (70 inches) on the southern




end of the coastal ranges to more than 380 centimeters (150 inches) on




the north.  There is also wide variability within some general areas,




for example, rainfall varies from approximately 410 centimeters




(160 inches) on the northwest tip of the Olympic Peninsula to less than




50 centimeters (20 inches) in the Dungeness area, 130 kilometers (80 miles)




to the east.  Inland eastward from the coast, precipitation decreases in




the Puget Sound—Willamette Trough, increases again in the Cascades,




drops very low in the arid central Washington valleys and plateaus, and




rises again in the Northern Rocky Mountain Province.





                                   39

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                                TABLE 1




MEAN MONTHLY AND ANNUAL VARIABILITY OF CLIMATIC CONDITIONS IN REGION
  Period
Precipitation
Temperature


January
July
Annually

January
July
Annually

January
July
Annually

January
July
Annually
cm

13
3
86

10
3
84

3
3
64

10
13
140
inches
Seattle, Washington
5
1
34
Meacham, Oregon
4
1
33
Potlatch, Idaho
3
1
25
Juneau, Alaska
4
5
55
°C

5
19
12

-3
17
7

_2
19
8

-4
13
4
OF

41
66
53

26
63
44

29
66
47

25
55
40
                                   40

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ENVIRONMENTAL PROTECTION AOENCT
tfOION X
1300 SIXTH AVENUE UATTU, WASHINGTON tRHM
WASHINGTON, OICOON, * IDAHO
ITE MEAN ANNUAL
PRECIPITATION
SCALE 1:1,000,000
DATE COMPLETED
JULY, 1974
DRAWN BV ^
CHECKED BY
&7
                                                                 SCALE OF MILES
FIGURE 11  MEAN ANNUAL PRECIPITATION

-------
     Snow is an important form of precipitation over most of the Region.



Mountain snowpacks furnish much of the summer streamflow to the larger



rivers.  Snow accumulates from December through March, and melts mainly



from April through July.  Stream throughout the Region drops to low



levels in summer and stream temperatures increase.



     Temperatures are moderate in coastal areas where, because of marine



influence, there is little frost in winter.  In the interior the climate



is continental with cold winters and hot summers; the winters are longer



and summers shorter at higher elevations.






SOUTHEAST ALASKA




     The climate is mostly maritime with considerable rain and moderate



temperatures.  The south coast averages 200 wet days per year, while



Raines and Skagway in the north average less than 100.  Transitional




climate occurs in higher mountains of the mainland.



     Regional annual precipitation in the form of snow and rain varies



from about 510 centimeters (200 inches) at Port Waller, 391 centimeters



(154 inches) at Ketchikan, 155 centimeters (61 inches) at Raines and



140 centimeters (55 inches) at Juneau.  Mean daily January temperatures



are -3°C (27°F) at Yakutat,  2oc (35°F) at Ketchikan and -4°C (25°F) at



Juneau.  Mean daily July temperatures range from 12°C (54°F) at Yakutat,



H°C (58°F) at Ketchikan and 13°C (55°F) at Juneau.  The rugged terrain



greatly influences temperatures and the distribution of precipitation,



creating considerable variations in both within relatively short distances




(13).

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                          FOREST STATISTICS






FOREST OWNERSHIP






     There are about 25 million hectares (65  million acres)  of  commercial




forest land in Region X (14).  "Commercial Forest Land"  is defined as




forest land producing or capable of producing crops of industrial  wood




(in excess of 20 cubic feet per acre per year) and not withdrawn from




timber utilization (14).  Ownership distributions for Region X  and for




individual states are shown in Figures 12 and 13 (15).




     "Coastal Alaska" as used in this report  is a geographical  area




described by the Pacific Northwest Forest and Range Experiment  Station,




U.S. Forest Service (45).  It includes southeast Alaska  and  a narrow




zone along the coast north to Kodiak Island.   The remainder  of  the state




is termed "Interior Alaska."




     There are about 43 million hectares (106 million acres) of forested




land in Interior Alaska.  By the above definition,  these are not classified




as "commercial forest land."  However,  commercial logging is being conducted




in some of the Interior forests.  As noted previously in this report,



other information dealing with Interior Alaska conditions has been




published.






LOGGING  ROAD ACTIVITY






     As of January 1, 1974, there is estimated to be about 400,000




kilometers (250,000 miles) of logging roads,  all ownerships,  in Region X




(16).  Within each State, the approximate totals,  were:





                                   43

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    59%
                                                17%
                                      PRIVATE (Industrial)

                                      PRIVATE (Farm & Misc)

                                      COUNTY A  MUNICIPAL

                                      STATE

                                      FEDERAL
TOTAL COMMERCIAL FOREST LAND:  26 MILLION HECTARES  (65 MILLION ACRES)
        FIGURE 12  OWNERSHIP DISTRIBUTION OF COMMERCIAL FOREST LAND,
                   ALL STATES,  REGION X

-------
              n
less them 1% H

    negligible E

           6% 9

          93% •
COASTAL
ALASKA
13  MILLION  HECTARES
(5.6  MILLION  ACRES)
                     PRIVATE (IND)
                   PRIVATE (FARM A MBC)
                   COUNTY A MUNICIPAL
                   STATE
                   FEDERAL
                                     IDAHO
                                     6.1 MILLION HECTARES
                                     (15.2 MILLION ACRES)
 WASHINGTON
 7.4 MILLION HECTARES
(18.4 MILLION ACRES
                                   OREGON
                                   10.4 MILLION HECTARES
                                  (25.7 MILLION ACRES)
     FIGURE 13  OWNERSHIP DISTRIBUTION OF COMMERCIAL FOREST LAND
               BY STATES REGION X

-------
     Oregon

     Washington

     Idaho

     Alaska (Coastal)
       175,000 kilometers (110,000 miles);

       155,000 kilometers (95,000 miles);

        70,000 kilometers (45,000 miles); and

       less than 5,000 kilometers (3,000 miles),
     On the average, including all ownerships,  about 13,000 kilometers

(8,000 miles) of new logging roads are built each year in the Region,  and

roughly 6,100 kilometers (3,800 miles) are rebuilt (16).   "Rebuilding"

(reconstruction) means relocating, substantially altering the original

road prism, or reexposing stabilized cut and fill slopes  of existing roads.

Although rebuilding a road does not usually add new roads to the system,

this activity is often similar to construction in potential water

quality impacts.

     The estimated average total miles of logging roads built every

year in each state of Region X are:
     Oregon
     Washington
     Idaho
     Alaska
      (Coastal)
 Kilometers

   5,700

   3,400

   4,400

   1,600

   2,600

   1,100

     300
Under 100 rebuilt
(Miles)
(3,500)
(2,100)
(2,700)
(1,000)
(1,600)
( 700)
( 200)

built
rebuilt
built
rebuilt
built
rebuilt
built
                                   46

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LOGGING  ROAD COSTS



     Road construction costs  vary considerably.  Factors which influence




this include:




     (a)  standard of road;




     (b)  amount of road surfacing needed  and location




          of suitable surfacing;




     (c)  number and size of  culverts  and  bridges;




     (d)  difficulty in excavating material—amount




          of rock, terrain, soil  types,  etc;




     (e)  density and size of vegetation to be  cleared




          and disposed of;




     (f)  organizational policies;




     (g)  amount and kinds of specialized  structures  and




          practices—e.g., bin walls,  end  hauling, etc.;




     (h)  overhead, engineering,  labor and materials  costs.






     There is a noticeable and consistent  difference  between  construction




costs east and west of the Cascade Mountains in both  Oregon and Washington.




In these States, the road cost per mile west of the Cascades  may range




from two to ten times more than that east  of the Cascades.  Reconstruction




has a similar cost pattern; but also varies according to the  degree  of




reconstruction.




     Table 2 summarizes construction and reconstruction for cost range




and for unit costs (16).

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                               TABLE 2

                 CONSTRUCTION AND RECONSTRUCTION COSTS
                   OF LOGGING ROADS IN EPA REGION X

             a — cost per kilometer,  thousands of dollars
             b — cost per mile,  thousands of dollars
                                                       Coastal
Oregon
a_ b_
Average 11 17
Minimum <1 1
Maximum 199 320
Average 5.5 .5
Minimum <.5 <.5
Maximum 15.5 25
Washington Idaho Alaska
a b_ a b a
Construction Costs
8 13 7 11 43
<1 <1 <1 <1 25
68 110 39 62 75
Reconstruction Costs
3.5 6 3 5 6
<.5 <.5 <.5 <.5 4.5
18 29 15 24 8.5
b_
70
40
120
10
7
14
     The estimated total average annual investment,  all ownerships,  in

construction and reconstruction of logging roads is  about $156,000,000

(16).  By states, the approximate investment is as follows:
              Oregon
              Washington
              Idaho
              Alaska
               (Coastal)
$59 million construction

 18 million reconstruction

 36 million construction

  6 million reconstruction

 18 million construction

  4 million reconstruction

 15 million construction

 Less than one million reconstruction


   48

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     These costs and investments include a range of variations in the



types and usage of water quality control measures including the



structures needed for this control.  Some measures appear to be used



consistently by most people, others more sporadically, and some only



rarely or by only some organizations.
                                   49

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        EFFECT OF LOGGING ROADS
               ON WATER QUALITY
     Water pollution is defined as man-made or man-induced alteration of
the chemical, physical, biological, and radiological integrity of water
(PL 92-500, Sec.  502(19)).  Implicit in the definition are various uses
of water to be protected.  Water quality generally relates to a degree
of excellence of  conformance to standards established for various uses.
     The discussions in this section are based on the assumptions that:
     (a)  Construction, reconstruction and use of logging roads
         will continue in the future.
     (b)  The use of logging systems requiring low density road
         systems will increase in some areas.
     (c)  Impacts on water quality caused by roads can be reduced
         but not completely eliminated.
     (d)  It is usually cheaper and more effective overall,  to
         prevent problems from occurring than to correct problems
         afterward.
     (e)  Consistent application of preventive technology that
         applies to areas of potential hazards will result  in
         significant reductions of water quality impacts.
     (f)  Current water quality standards probably do not adequately
         reflect realistic upper limits for nonpoint sources of
         water pollution in some areas.
                                51

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     GENERAL WATER QUALITY PROBLEMS AND PROTECTION CONCEPTS






     Forest lands are  the best source of high quality water on a yield



per hectare "basis.  In comparison to runoff from other major land uses



as agriculture,  grazing,  etc.,  runoff from forests is high in yield and



generally of good quality.  It is well  documented that the quality of



this water may be affected by the number and location of forest roads




in watersheds and the  manner in which they are constructed and main-



tained (1, 5, 17, 18,  19, 20).



     Potential water quality impacts caused by logging roads are best



dealt with by prevention or by minimizing their effects, rather than



attempting to control  them after  the fact (21).  For example, controlling



sedimentation from a mass soil movement and channel scour area often is



virtually impossible after the occurrence (short of a massive correction



and/or backstop system).



     Practices designed to prevent short-term and long term problems may



sometimes cost more initially;  however,  evaluation of available alterna-



tives and options now  in use should result in workable solutions.



     Hartsog and Gonsior (22),  in a report analyzing the performance of



a road project in Idaho,  indicate that,  "a gap remains between the possible



and achieved results in many road projects."  In some instances where all



apparent practical measures were  taken  to achieve a quality result,



problems still occurred.  Similar gaps  between possible and achieved



results were observed during the  EPA  field review of logging roads in




Region X.
                                    52

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     The above information suggests that:



     (a)  A strong preventative approach is not necessarily free of



          failure, and supplemental backstop corrective measures



          usually are also necessary to minimize sedimentation,  and



     (b)  Although much progress is being made in recognizing the



          potential water quality impacts of roads,  additional



          improvements are still necessary to minimize many of the



          common recurring road problems.






LOGGING ROAD  SEDIMENT






     Sediment has consistently been identified as the most significant




pollutant resulting from timber harvesting (l, 19, 20, 23, 24, 25).



Sediments are produced from forest lands by surface erosion, mass soil



movement, and channel erosion.  Logging road activities may influence



all of these and especially accelerate the surface erosion and mass soil



movement.



     There is considerable evidence that logging roads are the primary



source of accelerated erosion and sedimentation caused by silviculture



activities.  Packer (23) concluded that, "of man's activities that disturb



vegetation and soil in mountainous terrain, few cause more damage to the



quality of water than the construction of roads."  Many others have sub-



stantiated Packer's conclusion.



     In central Idaho, Megahan and Kidd (17) reported that nearly 84



percent of all sediment resulting from surface erosion on logging roads
                                    53

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was produced during the first year after construction.  Sediment




production decreased substantially after the first year to less than




10 percent the second year, and less than 3 percent annually for the




remaining four years of the study.  The Frewing Committee Report on




Management of Forest Resources in the Bull Run Watershed near Portland,




Oregon (40), indicates that on the basis of regional statistics,




70 percent of the sedimentation in streams resulted from road construc-




tion rather than any particular type of logging practice.




    In a study by Fredriksen (38) in the Oregon Cascades, 1.65 miles




(2.66 kilometers) of road were constructed in a steep 250 acre




(101 hectare) watershed.  Immediately after construction, storms caused




the stream to carry 250 times (1,850 mg/l) more sediment than the




undisturbed watershed nearby.  Within two months,  the sediment content




diminished to only slightly above preconstruction levels.  This research




and other similar research (17, 26, 27) and field observations as shown




in Figures 7 and 9,  all demonstrate the essential need for a concurrent




erosion control plan with road construction.




    The most common and significant water quality impact from forest




roads in much of the Region results from mass soil movements as discussed




in the section on major physiographic and soil variations.  In most cases,




mass soil movements are caused by undercutting unstable slopes, improperly




constructing embankments,  wasting of excavated materials on steep unstable




slopes, and drainage system failures (5, 28).  Evaluation of the mass




failure potential of a road corridor is essential to minimize water quality




impacts.




                                    54

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    The compacted surfaces of logging roads often carry road surface




runoff, with sediment during storms (l).  Roads increase surface




erosion by baring soil and concentrating runoff.  The amount of surface




erosion associated with roads is proportionate to the road density.   It




is well documented that as the miles of road increase in a watershed,




the potential for water quality degradation also increases.  Rosgen (29)




used road density as a factor in evaluating and predicting response of




a watershed to logging and road building activities.




    To minimize water quality impacts from roads, prevention and control




measures must be considered in every part of road planning, design,




construction, maintenance, and use.  The erosion control plan (plan of




implementation for minimizing erosion such as seeding, mulching,




terracing, use of structural measures, etc.) must be part of the planning




process with erosion control measures being applied concurrently with




construction, whenever practical.






Water Quality Problem Areas






    It is obvious from field reviews of road activities in much of the




Region that road construction is being extended further into rugged




topography.  Many of the easily accessible commercial forest sites have




been harvested.  Therefore, as the difficulty of construction (because of




topography, geology, soils, climate, etc.,) increases, the potential of




water quality impacts near sources of good quality water in mountainous




watersheds also increases.  As suggested by Tarrant (30), the key to
                                   55

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producing multiple benefits from the forest, including good quality




water, is the amount of care that the forest watershed manager can and




will exert in all his activities.




    Several recurring water quality problem areas were observed during




field reviews of logging roads in the Region.  The most frequently




recurring problems or problem situations are summarized below.  Most of




the items listed are interrelated.  For example, an adequate reconnaissance




survey should identify and assess potential location,  stability and




drainage problems.  The items are separated only for discussion purposes




to identify the most frequently observed water quality related aspects




of logging road planning,  design, construction,  maintenance and use




problems.  This listing is not intended to be comprehensive or to




include all of the problems related to roads.  Also, items are not




listed on the basis of priority.






    Reconnaissance Survey, Looat-Lon,  Unstable Slopes and Drainage.   The




lack of an adequate reconnaissance survey causes many water quality-




related road problems.  Many potential water quality impacts can be




identified, minimized, or eliminated as a result of an adequate




reconnaissance survey.  Site specific information on such factors as




geology, soils and climate should be obtained during the survey, as




discussed in Part II.  Proper road location initially will avoid or




minimize water quality impacts.  In general, as the proximity of roads




to streams and water bodies increases, the potential of degrading water




quality also increases.
                                   56

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         In steep or unstable topography, road construction often causes



greater soil disturbances, especially mass movement, than any other



forest activity.  In many instances, stability is an inherent problem




because of the limitations of the site.  Water volume and velocity



controls detachment and transport of soil particles.  Water running



long distances (over 427 meters, 1,400 feet) observed in some areas



along roadsides, in ditches, or down the roadbed is one of the most



common occurrences that degrade water quality in the Region.  Erosion



from long transport distance is shown in Figure 14.  Lack of energy



dissipators at culvert outlets to prevent water from being discharged



directly on fill slope is also a common cause of erosion and subsequent



sedimentation; culvert outlets with and without dissipators are illus-



trated in Figure 15.  Adequate subsurface drainage is essential to



reduce mass movement events.  Water adds a buoyancy to the soil mass



reducing shearing resistance resulting in mass failures.  Avoiding



concentrations of water in road cuts and fills will help minimize mass



failure problems.



     Erosi-on First Hear After Construction^ Season of Use.   Because



freshly-exposed material is highly susceptible to erosion, it is



estimated that approximately one-half to two-thirds of the erosion from



a road occurs during the first year after construction, except for mass



failure related discharges.  An example of first year damage is shown in



Figure 16.  Heavy road use during periods of precipitation and soil



saturation may result in immediate water quality degradation, as shown
                                   57

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FIGURE 14  EROSION FROM LONG WATER TRANSPORT.
                     58

-------
WATER QUALITY IMPACT FROM LACK OF ENERGY DISSIPATOR.
         MINIMAL WATER QUALITY  IMPACT WITH
             USE OF CULVERT DISSIPATOR.

             FIGURE 15 CULVERT OUTLETS

                         59

-------
       09
asn do NOSVUS  LI
'Savon ONIOOOT oi
              XSHU  91

-------
in Figure 17.  Use of logging roads by hunters and recreation visitors



produce similar-type impacts.  The degradation is usually short-term or



until rainfall or snowmelt decreases.  However, the combined impacts of




such activities on watersheds may result in significant deterioration



of both water quality and the roadbed.




     Road Density.   The miles of road constructed is related to the



timber harvesting method.  Detailed aspects of the relationship between



logging systems and roads is beyond the scope of this report.  However,



it is generally recognized that harvesting methods that reduce the kilo-



meters (miles) of road result in less water quality impacts (18, 26).



     Sources of Surfacing Materials.   Locating adequate sources of



surfacing materials for roadbeds is a problem in many parts of the




Region.  The highly weathered nature or absence of accessible rock



materials creates the problem.  The disturbance due to excavation and



removal may cause water pollution problems.  Streambeds and water bodies,



such as beaches in areas as southeast Alaska, are often used as sources



of surfacing materials.  However, removing the accumulated alluvial



gravels from these areas may produce serious sedimentation and water



quality impacts where removal is done below the existing water level.



     Channel Crossing.   Roads are often required to cross streams in



order to take advantage of the landform or to minimize construction and



related difficulties.  This is one of the primary causes of water quality



problems associated with roads.  Immediate and long term water quality



impacts often occur in these areas, from disturbance within the stream
                                   61

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and from blockages of culverts and failures.   The number of road channel



crossings in a watershed is an important  factor  in  evaluating water



quality response to disturbance (29).






    DETERMINING POTENTIAL FOR POLLUTION FROM LOGGING ROADS






     An appreciation and understanding of the  intent and objectives of



some of the commonly used stream classification  systems is essential



for water quality protection in areas  with logging  road activities.



Consideration of water quality and stream classifications should be



part of all phases of logging road planning, design, construction and



use.



     It has been recognized for sometime  that  the type of water uses to



be protected are important in determining necessary quality criterion.



The classification of water bodies on  the basis  of  desired use is often



a convenient and useful mechanism for  decision making by land managers



and regulators.  As noted earlier in this report, the FWPCA Amendments



of 1972, identify uses of water to be  protected.



     States in Region X have various types of  stream and lake classifi-



cations relating to kind of water use,  most refer to this use or zoning



as a stream classification system.  The systems  are related to such uses



as domestic supply, fishery,  recreation,  industrial, agriculture, and



aesthetics.  Inherent in any use classification  related to natural



resources are potential conflicts requiring the  establishment of prior-



ities.  The use priorities are included as part  of  the water quality




standards of the States.




                                  62

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     Some of the stream classification systems used in the Region are




presented in Table 3.  The number of classes varies from two to five.




The system of the Department of Fish and Game in Alaska is based on




streams being specified as important for anadromous fisheries.  The




system however, is not all inclusive and lack of classification does




not indicate unimportance.  Specification of a stream is usually related




to a significant project or action that has a potential for impacting




anadromous fishery values.  The major elements of systems used by other




states in the Region are included in Table 3.




     The differentiating criteria used in most of the systems have many




common parameters.  For example, value for domestic use, importance for




angling or other recreation, and use by significant numbers of fish for




spawning, rearing or migration are used in most systems.  The continuity




of water flow as intermittent or perennial is also included in some




systems.






OTHER  USE CLASSIFICATIONS






Standards




     The water quality standards of the States in the Region are also




related to water use classifications.  The designated use for which waters




of the various States are to be protected include, but are not necessarily




limited to, domestic and industrial supplies, irrigation and stock water-




ing, fish and wildlife, recreation and aesthetic qualities.  The States




have general and special standards for specifically designated waters.
                                  63

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         COMPARISON   OF   S

   States             Alaska

Legislative Basis.  Alaska Statutes
                     16.10.010.

Number of Classes.  None.
                                                TABLE  3

                   OME   STREAM   CLASSIFICATION   SYS

                          Idaho                     Oregon

                     Administrative Decision of  State Forest Practices
                       Dept. of Fish & Game.
Differentiating
 Criteria.
Requirements.
 Activities
  Controlled.
The Dept. of
 Fish & Game
 may classify
 waters as
 important for
 spawning or
 migration of
 anadromous
 fish.
Written approval
 for activities
 in specified
 streams of ana-
 dromous fishery
 value.
Instream acti-
 vities in speci-
 fied anadromous
 streams as
 obstruction,
 diversion,  and
 pollution of
 spawning beds.
I thru V.

Aesthetics.

Availability
 (road access).

Use (fishing pressure).

Fish productivity.

Size.


None.
                                          None.
 Act.

I and II.

Value for domestic use.

Important for angling,
 or other recreation.

Use by significant
 numbers of fish for
 spawning, rearing or
 migration routes.
Notification of opera-
 tion.

Requires reforestation,
 cleanup and protection
 (more stringent depend-
 on class).

Timber harvesting includ-
 ing reforestation, fell-
 ing, bucking, yarding,
 decking, and hauling
 road construction.

Treatment of slash &
 site preparation.

Application of Chemicals

Pre-commercial thinning.
TEMS   USED   IN   R

   Washington

 State Forest Practices
  Act.2

 I thru V.

 Value for  domestic use.

 Important  for  angling
  or  other  recreation.

 Use  by  significant
  numbers of fish for
  spawning,  rearing or
  migration.

  Water  flow continuity.

 Plan of operation,
  reforestation,  cleanup
  and protection (more
  stringent depending on
  class).
E G I 0 N   X

 Forest  Service, Region 6

 Administrative Decision
   of Regional  Forester.

 I thru  IV.

 Direct  source for domestic
   use, including recreation
   sites  used by large numbers
   of fish for  spawning, rear-
   ing or migration as a major
   influence  on water quality.

   Water  flow continuity.
  Streams must be classified
   as streams!de management
   units, cleanup and pro-
   tection (more stringent
   depending on class).

  Timber falling, yarding.
                                                          Application of chemicals.

                                                          Disposal of slash.

                                                          Road construction and
                                                           maintenance.->

                                                          Harvesting.

                                                          Reforestation.
                              Man-caused woody debris into
                               streams.

                              Roads.

                              Livestock grazing.
 I/ Rules and regulations for Stream Channel Protection Act (Title 42,  Chapter 38,  Idaho Code)
    specifies minimum standards for stream channel alterations.

 i/ Act will govern all  forest practices after Jan. 1, 1975.  Information in table from interim
    guidelines for 1974  prepared by Ad Hoc Committee sponsored by State Department of Natural
    Resources.  Formal rules and regulations will "be adopted Jan. 1, 1975.

 I/ State hydraulics project approval law (for channel alteration) and Shoreline Management
    Act controls  some activities on forest land.

-------
The designations include lakes, streams, segments of streams, or river




basins.  Various classes related to the uses as M,  A,  B, C through G




inclusive are also used to identify specific bodies of water.




     The criteria in the water quality standards are related to the




classes.  A detailed discussion of water quality standards is beyond




the scope of this report.  The concepts and principles related to use




classifications are introduced only for completeness.  References 31,




32, 33;. 34, provide detailed information on State water quality standards,






Basin Plans






     Basin plans are developed to document pollution problems for some




of the States in the Region,  Most of the States have a continuing




planning process (Sec. 303(e) FWPCA).  The process provides the method




for the States to coordinate their water quality management planning,




programming, and management.  The basin plans identify and document the




nature, source and extent of water quality impacts and procedures for




minimizing the impacts.  Stream segments in the basin are classified as




part of the plan development.  The classification of segments is based




upon measured instream water quality when available.  Basin stream




segments are classified as water quality limited or effluent limited.




These stream classifications are used to identify water quality problem




areas and assist in setting priorities for pollution abatement.
                                   65

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     The definitions of classified basin stream  segments are as follows:






     Water Quality Limitation.    Any segment where  it  is known that



water quality does not meet applicable  water quality standards and/or



is not expected to meet applicable water quality standards  even after




the application of the effluent limitations required for point sources



of pollution (FWPCA—Sections 30l(b)(l)(A) and 30l(b )(l)(B)).






     Effluent Limitation.    Any segment where  it is known that water



quality is meeting and will continue to meet applicable water quality



standards after the application of the  effluent  limitations required




for point sources of pollution.






                   WATER QUALITY RISK ANALYSIS






     A rational assessment of the potential water quality impacts of




roads is an important ingredient of an effective water quality  control



program.  The following discussion is intended to highlight the  con-



ceptual framework of risk analysis.  More detailed information  and



evaluation techniques are covered in Part II  of  this report.



     A number of different risk analysis procedures are being used to



assist in estimating the potential consequences  of road construction



activities (and other silvicultural activities).  The following examples




illustrate some of the analytical approaches.
                                   66

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     A risk analysis procedure to evaluate the potential for waste



discharge caused by logging roads is proposed by Jones and Stokes (21).



A number of risk factors and evaluation criteria are identified,  and



the relationship of various practices to potential water quality



degradation is explained.  A somewhat arbitrary correlation was developed



between the factors and those road practices suitable for such an



analysis.  However, on the basis of much of the available research and



field observations, the basic risk factors are accurate and do apply



to road activities in Region X.



     Rosgen (29), in northern Idaho, uses a watershed response rating



system which considers six criteria for evaluation:  surface erosion



hazard, mass wasting hazard,  recovery potential of the land, stream



channel stability, stream recovery potential, and road impact index



(road density times the number of stream crossings).  This system is



designed to help analyze the hydrologic response of a watershed to



climatic events and man's activity on the land.  As part of this  system,



recommended prescriptions are developed as needed for minimizing



potential impacts of roads (and other activities) on water quality



( and other resources).



     A geologic hazards approach was used for the Portland, Oregon



Bull Run watershed (ll).  As discussed earlier, Kojan et al (3)




developed a system of risk analysis based on geologic hazard and  mass



erosion susceptibility.
                                   67

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     The following concepts are  included in most  of  the risk  analysis




systems:



     (a)  identification of potential problems  (i.e., water




          quality impacts);



     (b)  identification of significant factors;



     (c )  evaluation criteria;



     (d)  estimating the probability of problem



          (water quality impact) occurrence;



     (e)  estimating the potential magnitude  of



          impact occurrence;



     ( f)  suggested criteria or solutions for



          preventing or minimizing impacts.






     However, it must be recognized that such analyses  are not "cure alls".



Rather they should be viewed as aids to recognizing  and assessing potential



water quality impact hazards in advance in order to  address them before



the fact.  Any such analyses still require judgment  and the "risk ratings"



derived are dependent upon the quality of the investigative work and the



predictive capabilities.  The art of predicting the  location and magnitude



of road-triggered events is neither precise nor refined.  For example,



problems are not always evident; the capability for predicting mass-wasting




on a site specific basis is not well-developed except in the most obvious



situations; and predicting the magnitude of problem occurrence with a



high degree of accuracy is not now practicable.
                                    68

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     An evaluation of some of the risk systems being used suggest  the



following conclusions:




     (a) Risk analysis  is an important feature of a strong




         water quality  management program.



     (b) Although such  systems cannot be viewed as highly



         accurate predictive devices,  they  are a rational



         basis for improving the probability of anticipating



         major water quality impacts (and thus an aid for



         preventing or  minimizing the impacts).



     (c) Multi-professional (i.e.,  geology,  soils,  hydrology,



         engineering, forestry) skills are  needed to develop



         high quality analyses and prescriptions—especially



         in high risk situations or areas.



     (d) Some form of detailed site evaluation is necessary.
                                  69

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   SURVEILLANCE AND MONITORING





            MONITORING NONPOINT SOURCES OF POLLUTION





     This  chapter will present an overview  of  some important aspects



of water quality monitoring relative to nonpoint sources of pollution.



The emphasis is on logging road activities; however, many of the concepts



presented  apply to other silvicultural activities and other nonpoint



sources of pollution.  The discussion is not intended to develop a how



to do it approach, or solve the many contemporary problems associated



with various aspects of water quality monitoring.  It is intended to



emphasize  some of the fundamentals and complexities involved in



monitoring related to logging road activities.



     Comprehensive water quality monitoring is a difficult,  expensive



and time consuming process.  It involves many  interrelated variables



such as time of sampling, frequency, flow characteristics, climate and



such physical considerations as soils, geology and topography.  Nonpoint



sources of pollution are not confined to discernible, confined and



discrete conveyances.  As a result,  nonpoint source pollution presents



uniquely difficult monitoring problems, because of the wide variability



of many physical factors.



     Measurement of a highly variable, diverse system such as found in



any natural system requires a great deal of effort.  Careful considera-



tion must  be given to determining if the end results are worth the costs



involved.  In many instances, the cost to obtain high quality data are
                                 71

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considered prohibitive and therefore something much less than optimum



is considered acceptable.  The less than optimum level of sampling is



generally utilized in everything other than a research study,  with the



end result being the data is almost useless in determining the cause-



effect relationships necessary to evaluate management activities.



     The FWPCA Amendments of 1972 is the first national legislation to



recognize pollution problems of a nonpoint source nature.  It is



recognized that the kind of pollution control for nonpoint source  areas



as silvicultural activities, cannot be the same as those for conventional



collection and treatment of polluted effluents immediately prior to



discharge into water bodies.  The treatment and control methods generally



relate to the forest management system.  They may include a combination



of practices and methods for minimizing pollutant discharges.



     The concepts for the control of pollution from point sources, or



discernible, confined and discrete conveyances, are clearly identified



in the Act.  The control regulations include, but are not limited  to



(a)  effluent limitation for point sources; (b)  application of best



practical control technology; (c)  compliance schedules to meet effluent



limitations; and (d)  compliance monitoring.



     There are some similarities between point sources and nonpoint



sources pollution problems.  The basic goal for both is to reduce  water



pollution.  The effects they cause are similar—they degrade the chemical,



physical, and biological integrity of water.  The major differences



between point sources and nonpoint sources are their mode of entry into
                                  72

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the aquatic environment, timing of pollution input, the levels of the



dispersion of material downstream, and most of all, the extreme



variation caused by a number of factors both natural and man caused.



These differences limit the application of conventional pollution



control methodology of treatment prior to discharge.



     Many of the transport pathways for pollutants from nonpoint



sources are not fully understood.  However, it is feasible to apply



the principles of best preventative techniques which are somewhat



similar in concept to best practicable technology for control of point



sources of pollution. Best preventative techniques are those procedures,



methods, techniques and structural measures which are currently avail-



able for preventing or minimizing water quality impacts.  Much of the



information presented in Part II includes best preventative techniques



for logging road activities.




     Some of the common needs for water quality monitoring are to:



(a) evaluate the presence of pollution; (b) define causes or sources of



pollution; (c) evaluate data for development of preventative measures;



and (d) determine the natural background quality of water in the water-



shed, and to be able to distinguish between natural and man-caused



sediment inputs in a system of extreme variability.



     Road construction and maintenance have short-term impacts during



and immediately following construction and generally decreasing long-term



impacts during the life of the roads.   However, in some instances road




cuts are progressively less stable as  roots rot and exposure causes

-------
weathering.  The major pollutant is eroded mineral sediments. Signifi-



cant, localized pollution problems can be caused by organic matter from



the forest floor and in the soil originating from plant and animal



sources; tree debris (another source of organic matter) in the form of



leaves, twigs, and slash; pesticides used in the maintenance program;



and nutrient elements (principally nitrogen and phosphorus) from soils




and plant and animal matter or from fertilizers.  Thermal pollution can



also occur by removing shade cover and exposing streamflow to solar



heat.  Of all these pollutants, sediment is the most serious cause of



water quality degradation (19).



     In many instances, it is difficult to determine what pollution



results from logging roads, what is caused by other man related



activities, and what is the natural background level.  The most



convenient and conventional approach is to monitor or quantify water



quality in an area without logging road construction, as was discussed



earlier related to work by Fredriksen (38).  The approach obviously has



limitations after initial reading of an area is started.  The subsequent



water quality impacts from road construction are difficult to separate.



Consequently, the most effective approach for documenting water quality



related to roads and other silvicultural activities is to monitor as



small a watershed as practical for cumulative impacts.  Larger water-



sheds should be used to document long term trends.



     The principal needs to increase effectiveness in nonpoint source



monitoring are:  (a)  a better definition by forest land managers and

-------
regulators of what and where monitoring should occur; (b)  a better




understanding and definition of the probability of sedimentation in




undisturbed areas within a defined time frame; and (c)  a better




definition of pollution levels and impacts.  Some important aspects




of nonpoint source monitoring that must be recognized in developing




a monitoring system are:




     a.  Sediment is the most significant pollutant from




         nonpoint sources on forest land in the Region.




     b.  Stream systems have naturally-caused sediment for




         any defined time frame.




     c.  Land management objectives should be related to




         a defined time frame in order to identify water




         pollution impacts.




     The above indicates that general prescription approaches for




monitoring nonpoint sources are of limited value.  Monitoring activities




should be related to a predefined purpose.






PARAMETERS AND FREQUENCY






     Monitoring should normally be limited to those parameters most




likely to be significantly affected by logging roads and relat-ed silvi-




cultural activities.  The most significant ones are sediment and




turbidity.  Temperature, dissolved oxygen,  nutrients, and chemicals such




as deicers,  oils and pesticides may require monitoring in special




situations.   Stream flow should also be measured to assist in interpreting




water quality data.





                                  75

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     The sampling frequency must be carefully established so that all




the ranges of water quality experienced from logging road and related




activities are observed.  Monitoring schemes must be built on knowledge




of how and when the pollutant is likely to be produced.  For example,




it is known that sediment enters streams primarily during storm events




or during the rising stage of streams.  It is also documented that




chemicals as deicers and oils used in dust-coating roads have the




greatest potential for entering streams during and immediately after




rainfall and runoff.  For water temperature monitoring, the sampling




should be geared to diurnal variations including mid-summer, midday




periods during clear hot weather (19).






Monitoring Approaches




     Two types of monitoring approaches may be used to document water




quality in a forested watershed—long-term or trend monitoring and short




term monitoring.






     Long Term Monitoring.   This type of monitoring is designed to




establish representative water quality for runoff and document long-term




fluctuations.  The monitoring stations should be on major drainages




within a watershed to represent the combined effect of all activities




within a drainage.  The information will give an overview of the quality




of water within the yield area.




     Many long term monitoring stations already exist in the Region and




are operated by the EPA, U.S. Geological Survey, U.S. Forest Service,
                                   76

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State Agencies, Universities and various timber industries.  In special



interest areas as municipal watersheds where logging roads are constructed




over a period of time, it may be desirable to establish long-term



stations to document water quality impacts.  The information may be used




in developing preventative and corrective measures.






     Short Term Monitoring.   This type is designed to monitoring project




activities before implementation (to establish existing quality), during



implementation (to establish the effect of the activity on quality as a



control) and after implementation (to establish time frames for return



to pre-disturbance conditions or recovery as a measure to quantify




degradation).



     Short-term monitoring stations should be located near activities



to be monitored.  The paired-station approach, one station upstream and



one station downstream, is the most convenient and conventional.  It is



appropriate for monitoring many road activities.  The shortest possible



time should occur between the two sample intervals.



     The potential limitations of the paired-station approach are (a)



In situ changes in pollutant concentration due to past natural—or—man



caused activities; (b) locating downstream stations to insure adequate



mixing, yet avoiding unrelated sedimentation or other pollutants from



instream areas; (c)  the approach does not indicate the frequency of



changes, or their meaning at water use points; (d)  in order to achieve



any degree of  statistical significance in the sampling procedure a
                                  77

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number of samples will be required.  In addition,  it way not be possible




to utilize this technique in certain instances. Many small watersheds



where monitoring is desirable occupy a position in the upper reaches of



a drainage system.  It may not be possible to establish a station



upstream and downstream of an activity in such a situation where a stream



originates within the activity area.




     It is essential to understand the limitations and applications of



any monitoring approach prior to its use.  Recognizing its limitations,



the paired station approach is still appropriate for monitoring logging



road activities in many instances, because the major impact during the



first year after construction generally occurs within a short time.



The approach is shown graphically in Figure 18.



     The technique of paired watershed analysis may also be used in



monitoring logging road activities as used by Fredriksen (38).  This



method is not without limitations, however it does have advantages in



certain instances.  The largest disadvantage is one of long calibration



time.  The principal advantage of the approach is that the control water-



shed may more accurately represent natural levels of water quality.






Parameters






     The water quality parameters most likely to be influenced by road



activities include sediment, turbidity, and temperature.  In some instances,




specific conductance, dissolved oxygen and stream discharge may be



affected.  The key parameters are discussed below:
                                   78

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SAMPLING POINT
                             POTENTIAL WATER USE
                             FISHING
                             SPAWNING
                             AREA
                                                 SPUR ROAD
                                                '/
                                                ' .^ SMALL
                                                   WATERSHED
                                                 ." BOUNDARY

                                                     MAIN HAUL
                                                ._£  ROAD

                                                ROAD
                                                CONSTRUCTION
                                                IN  PROGRESS
                                    POTENTIAL
                                    WATER USES
                                    MUNICIPAL
                                    SUPPLY
                                    FISH REARING
FIGURE 18  WATER  QUALITY MONITORING APPROACH FOR CUMULATIVE IMPACTS
                            79

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     Sediment.   As previously discussed,  sediment is the major



pollutant related to logging road activities.   Detail quantification of



sedimentation sources, rates, etc.,  present difficult problems because



of wide variability of flow, soil, and geologic characteristics of an



area.  Many of the problems involved in monitoring and interpreting



sediment transport and deposition data are well documented in literature




(1, 12, 19, 24, 36, 46, 47).



     To evaluate the relative contribution of sediment sources and



transport processes that affect streams in the forest, problems in



monitoring sedimentation characteristics should be recognized.  They



involve determining where in the watershed the characteristic should be



measured or identified, and how well the sample represents time and



spatial variations (37).  In evaluating the contribution of sediment



sources from roads and other forest activities, environmental character-



istics such as the hydrology of the soil,  the landform which the soil



occupies, the erosional processes, and the high sensitivity of each



process to change must be considered in surveillance and monitoring



activities.  Erosion is but one of the three basic processes of  sedi-



mentation, the other two are sediment transport and deposition.  Each



of these basic processes may in turn serve as a source of sediment or



be involved in the transport process, depending on the particular



measurement of sediment delivery being considered.



     Much of the available information on sedimentation from forest



land activities including roads has come from subjective evaluations or
                                  80

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observations of muddy streams during and following road construction and



use.  In some instances, research has provided quantitative data on



sediment production from forest roads built prior to other types of man



caused disturbances in an area (17, 26, 38, 39).  Most of the quantitative



information that's available on impacts of forest roads on water quality



have been obtained from experimental watersheds.  Some of these water-




sheds have had complete timber harvest operations (24, 38).  Others



have been located in soils and geologic materials that are of relatively



minor importance making the transportability of some of the information



questionable.  More baseline information on various common road acti-



vities and other forest land management practices is needed to better



understand and quantify water quality impacts associated with logging



road activities.






     Turbidity.   It is a measure of an optical property of water



normally expressed in Jackson Turbidity Units (JTU).  Turbidity may be



related to the suspended sediment content of the water although the



correlation may be quite variable from stream to stream and even for



the same stream at different locations and times of the year.  Turbidity



gives only a crude index to sediment content, unless a specific correla-



tion for a stream is developed.






     Temperature.    The purpose of water temperature monitoring is to



determine whether shade removal or ponding increases water temperature.




If shade is not removed as a result of stream crossings or other
                                  81

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construction in the immediate vicinity of streams or any ponding effects



introduced, the monitoring of water temperature loses its primary



importance.




     In some instances, it may be well to consider measurements of




monitoring outside the standard water quality parameters discussed above.



As discussed, these parameters are so highly variable it may be advis-



able to evaluate both source area and end results for a measurement of



the impact of the logging road activity.  Analyzing source areas is



particularly important where mass failures are involved.  In addition,



measurement of changes to the aquatic system or biological monitoring



should also be considered.  Such things as measuring channel erosion and



degradation, and changes in particle size distribution of deposits may



be helpful in determining effects of logging road activities on the



aquatic system and other water uses.






USE OF  WATER  QUALITY DATA






     Good water quality data can provide a means of assessing the effec-



tiveness of various erosion control measures and engineering design



features.   The information should encourage designers and contractors to



make a more conscientious effort to prevent water quality degradation.



Water quality information may also be helpful in controlling construction



and related road activities.



     There are several sources of water quality data that can be used



by planners or engineers to assess the potential water quality impacts
                                   82

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of roads and other silvicultural activities.  The Environmental Protection




Agency, U.S. Forest Service, U.S. Geological survey, State water pollu-



tion control agencies, and universities in the Begion all have water




quality data related to various aspects of forest land management.



     Most of the groups have inventories of data collected.  The EPA's



STORET System also contains data of most of the other agencies and



groups.  The system is a comprehensive source of water quality data



and may be useful for planners and engineers, especially during the



planning and design phases of logging roads.  Data can be retrieved



at Region EPA Offices (19).

-------
                               REFERENCES
Text
No.

1.    Brown, George W.  Forestry and Water Quality.  School of Forestry,
      Oregon State University, Corvallis.  1973.

2.    Way, Donald S.  Terrain Analysis.  A Guide to Site Selection Using
      Aerial Photographic Interpretations.  Community Development Series.
      1973.

3.    Kojan, E., J. R. Wagner and R. M. Wisehart.  Environmental Impact
      Report, Fox Unit Study Area, Six Rivers National Forest, Del Norte
      County, California, Unpublished.1973.

4.    Swanston, D. N. and C. T. Dyrness.  "Stability of steep land."
      Journal of Forestry.  1973.  71:264-269.

5.    Burroughs, E. R., G. R. Chalfant and M. A. Townsend.  Guide to Re
      duce Road Failures in Western Oregon.  Bureau of Land Management,
      Portland, Oregon.1973.

6.    U. S. Environmental Protection Agency.  Region X.  "Slope Calcula-
      tions."  Data from U. S. Forest Service, Regions 1, 4 & 6 and PNW
      and Intermountain Research Stations.  Unpublished.  1974.

7.    Allison, Ira S.  "Landforms of the Northwestern States."  Atlas of
      the Pacific Northwest.  Edited by R. M. Highsmith, Jr.  Oregon
      State University, Corvallis, 1968.  pp. 27-30.

8.    Baldwin, E. M. Geology of Oregon; Distributed by University of
      Oregon Cooperative Bookstore, Eugene.  1964.

9.    Campbell, C. D. "Washington geology and resources."  State College
      Wash. Res. Stud.  1953.  21: 114-153.

10.   Fairbridge, Rhodes W.  Encyclopedia of Geomorphology.  Earth Science
      Series, Volume III.  1961T

11.   State of Oregon.  Department of Geology and Mineral Industries.
      "Geologic Hazards of The Bull Run Watershed Multnomah and Clackamas
      Counties, Oregon."  Bulletin 82.  1974.

12.   Pollution Control Council, Pacific Northwest Area.  Watershed Con-
      trol for Water Quality Management Reproduced by U. S, Public Health
      Service.  1961.

13.   NOAA—National Weather Service.  Climate of Alaska.  Anchorage,
      Alaska.  Undated.
                                    85

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                          REFERENCES (Cont'd)
Text
No.
14.   U. S. Forest Service.  The Outlook for Timber in the United States.
      Forest Resource Report No. 20.  U. S. Government Printing Office,
      Washington, D. C. 1973.

15.   U. S. Environmental Protection Agency, Region X Silviculture Project
      Staff.  "Forest Land Statistics for Region X."  Unpublished.  1974.

16.   U. S. Environmental Protection Agency, Region X Silviculture Project
      Staff.  "Summary of logging road information from various sources."
      Unpublished.  1974.

17.   Megahan, W. F. and W. J. Kidd.  "Effects of logging roads on sedi-
      ment production rates in the Idaho Batholith."  USDA Forest Service,
      Research Paper INT.-123.

18.   Rice, R. M., J. S. Rothacher and W. F. Megahan.  "Erosion consequen-
      ces of timber harvesting:  An appraisal."  Proceedings of a Sympos-
      ium on Watersheds in Transition, Ft. Collins, Colorado, June 19-22,
      1972.  pp. 321-329.

19.   U. S. Environmental Protection Agency.  "Processes, Procedures and
      Methods to Control Pollution Resulting from Silvicultural Activities."
      Office of Water Programs, Washington, D. C.  1973.

20.   Haupt, H. F. and W. J. Kidd, Jr.  Good logging practices reduce
      sedimentation in central Idaho.  J. Forest.  1965.  63: 664-670.

21.   California State Water Resources Control Board.  "A Method for
      Regulating Timber Harvest and Road Construction Activity for Water
      Quality Protection In Northern California."  Prepared by Jones and
      Stokes Associates, Inc.  Publication No. 50.  1973.

22.   Hartsog, W. S. and M. J. Gonsior.  "Analysis of Construction and
      Initial Performance of The China Glenn Road, Warren District,
      Payette National Forest."  USDA Forest Service, General Technical
      Report INT-5.  1973.

23.   Packer, Paul E.  "Forest treatment effects on water quality."  Conf.
      Proc. on Forest Hydrology, 1%7, pp. 687-699.

24.   Brown, George W. and James T. Krygier.  "Clearcut logging and sedi-
      ment production in the Oregon Coast Range."  Water Resources Re-
      search, -1971,  7(5): 1189-1199.
                                   86

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                         REFERENCES (Cont'd)
Text
No.
25.   Krygier, J. T. and J. D. Hall, Editors.  Proceedings of a Symposium
      "Forest Land Use and Stream Environment."  Oregon State University,
      Corvallis.  1971.

26.   Anderson, H. W. and J. R. Wallis.  "Some interpretations of sediment
      sources and causes, Pacific Coast Basin in Oregon and California."
      Proceedings of the Federal Interagency Sedimentation Conference, 1%3>
      Misc. Pub.  970.  1965.  pp. 22-30, USDA, Washington, D.C.

27.   Rice, R. M. and J. R. Wallis.  How a logging operation can affect
      strearaflow.  Forest Ind.  1962.  89(11), pp. 38-40.

28.   Larse, Robert W.  "Prevention and control of erosion and stream
      sedimentation from forest roads."  Proceedings of a symposium
      "Forest Land Use and Stream Environment."  Oregon State University,
      Corvallis,  1971.  pp. 76-83.

29.   Rosgen, Dave R.  "Watershed response rating system."  Forest Hy-
      drology  Hydrologic Effects of Vegetation Manipulation, Part II.
      USDA Forest Service, Missoula, Montana.  1974.

30.   Tarrant, Robert F.  "Man caused fluctuations in quality of water
      from forested watersheds."  Proceedings of the Joint FAO/U.S.S.R.
      International Symposium on "Forest Influences and Watershed Manage-
      ment, "  Moscow, U.S.S.R., 1970.

31.   State of Alaska.  Title 18.  Environmental Conservation Chapter 70.
      "Water Quality Standards."  1973.

32.   State of Idaho.  Department of Environmental and Community Services.
      "Water Quality Standards and Wastewater Treatment Requirements."
      1973.

33.   State of Oregon.  Department of Environmental Quality.  "Standards
      of Quality for Public Waters of Oregon and Disposal Therein of Sew-
      age and Industrial Waste."  1973.

34.   State of Washington.  Department of Ecology.  "Water Quality Stan-
      dards."  1973.

35.   Dyrness, C. T.  "Mass soil movement in the H. J. Andrews Experimental
      Forest."  USDA Forest Service, Research Paper PNW-42.  1967.

36.   U. S. Environmental Protection Agency.  National Environmental Re-
      search Center.  "Report on Nonpoint Source Monitoring."  Unpublished
      Draft.  1974.

                                   87

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                          REFERENCES (Cont'd)
Text
No.
37.   Anderson, H. W.  "Relative contributions of sediment from source
      areas and transport processes."  Proceedings of a symposium, "Forest
      Land Uses and Stream Environment."  Oregon State University, Corvallis,
      1971.  pp. 55-63.

38.   Fredriksen, R. L.  "Erosion and sedimentation following road construc-
      tion and timber harvest on unstable soil in three small Western Oregon
      Watersheds."  USDA Forest Service, Research Paper PNW-104.  1970.

39.   Packer, Paul E. and Harold F. Haupt.  "The influence of roads on
      water quality characteristics" in Proceedings of "Society of Ameri-
      can Foresters,"  Detroit, Michigan,  1965.

40.   Frewing Committee Report.  "Management of forest resources in the
      Bull Run Watershed near Portland, Oregon."  1973.

41.   Joint Federal State Land Use Planning Commission for Alaska.  Re-
      sources of Alaska A Regional Summary,  1974,  p. 8.

42.   Ibid,  p. 586.

43.   Ibid,  p. 588.

44.   Swanston, D. N.,  "Principal Mass Movement Processes Influenced
      by Logging, Road Building and Fire."  Proceedings of a symposium
      "Forest Land Uses and Stream Environment."  Oregon State University,
      Corvallis,  1971,  pp. 34-36.

45.   Hutchison, K. 0., Alaska's Forest Resource, USDA Forest Service,
      Institute of Northern Forestry, Resource Bulletin PNW-19, 1968.

46.   Guy, Harold P., Techniques of Water Resources Investigations of
      the United States Geological Survey.  "Field Methods of Measure-
      ment of Fluvial Sediment."  U. S. Government Printing Office,
      Washington, D. C.,   1970.

47.   Guy, Harold P. and Vernon W. Norman,  Techniques of Water Resources
      Investigations of the United States Geological Survey.  "Fluvial
      Sediment Concepts."  U. S. Government Printing Office, Washington,
      D. C.,   1970.
                                   88

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              PARTH

Engineering Design And Technical Criteria
      For The Control Of Sediment
         From Logging Roads
                and
        The Control Of Pollution
   From Road Maintenance Chemicals

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                  INTRODUCTION
     Engineering criteria for the planning, design,  construction and
maintenance of logging haul roads directed toward sediment minimization
is a part of the total engineering criteria need for these roads.  The
appropriate spectrum of this criteria is related to  the major role log-
ging roads play in forest land management.
     Sediment control design criteria may be the same as, or parallel to,
other design criteria that will result in an efficient, economic logging
road system for sound forest land management.   Examples of "overlap" or
parallel criteria are:
     1.   Relating road location and design to  the total forest resource,
         including short and long term harvest patterns, reforestation,
         fire prevention, fish and wildlife propogation and water quality
         standards.
     2.   Relating road location and design to  current timber harvesting
         methods.
     3.   Preparing road plans and specifications to  the level of detail
         appropriate and necessary to convey to the  road builder, be he
         timber purchaser or independent contractor,  the scope of the
         project  and enable him to prepare a comprehensive construction
         plan of  procedure, time schedule, and cost  estimate.
     4.   Design investigations and companion design  decisions directed
         toward minimizing the opportunity for "changed conditions"
         during construction with their consequent costs in dollars and
         time.
                                 91

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     5.  Analysis of certain road elements relative to first cost versus



         annual maintenance cost such as culverts and embankments versus



         bridges; ditch lining versus ditches in natural soils; paved



         or lined culverts versus unlined culverts; sediment trapping



         devices (catch basins, sumps) versus culvert cleaning costs;



         retaining walls versus placing and maintaining large embankments



         and embankment slopes; roadway ballast or surfacing versus



         maintenance of dirt surfaces; and balanced earthwork quantities



         versus waste and borrow.




     Specifically including design criteria to minimize sediment can



broaden the design criteria spectrum under some conditions.  In these cir-



cumstances additional first cost may not result in companion annual main-



tenance cost reductions as suggested in the previous paragraph.  Examples



of these circumstances are:



     1.  Spur roads built for one harvest in one season of a small area



         and/or to one use landings.



     2.  Short-term sedimentation control measures during road construc-



         tion and immediately thereafter until long-term measures are



         installed or established.



     3.  Improvements outside of what has been regarded as the road



         right-of-way, or corridor, such as specially constructed filter



         strips, "downhill" culvert extensions, settling basins and pro-




         visions for debris collection.



     4.  End haul of excess excavation to selected waste areas.



     5.  More restrictive limitations on the road construction season






                                 92

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         thereby, in some instances,  requiring more seasons to complete



         the road with companion delay in the timber harvest (time cost




         of money).



     6.   "Tipping the scales" in an evaluation of a fragile or sensitive



         area toward the conclusion that existing road design and con-



         struction technology will allow no_ road construction.



     7.   Restriction or elimination of a timber harvest method due to the



         road needs of the method and conversion to another harvest method



         that results in a higher long term harvest cost.



     Many regional writers believe that forest roads have  often signifi-



cantly contributed to sediment reaching streams by road surface erosion



and mass soil movement.  George W. Brown states that:  "The compacted sur-



faces of logging roads, skid trails,  and fire lines often  carry surface



run-off during storm events.  Road surfaces are a significant source of



sediment in forest because of such run-off" (l).  Fredriksen's studies in



Western Oregon watersheds report that "Landslides are the  major source of



stream sedimentation" and that "their occurrence is more frequent where



logging roads intersect stream channels" (2).  He also suggests that mid-



slope road mileage be minimized and further where these roads are neces-



sary across steep side slopes, "all knowledge available to the engineer



should be used to stabilize roads".



     Swanston's investigations on mass soil movements in forests indicate



that road building is the most damaging activity and believes that soil



failures therefrom result primarily from slope loading with embankments,




sidecasting, inadequate provision for slope drainage and cut slopes (3).
                                 93

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Mass movements have occurred in the Alaska maritime coast, Idaho and

on the western slopes of the Cascades.  These movements have often

produced companion sedimentation problems and significant water quality

degradation.

     Megahan and Kidd's studies of sediment production rates in the

Idaho Batholith showed increases of sediment production an average of

770 times per unit area of road prism for a six year study period (4).

Although surface erosion following road construction decreased rapidly

with time, major impact occurred from a road fill failure after a single

storm event.

     This section deals with engineering techniques that have been used

or can be used to minimize the sedimentation originating from logging

haul roads.  The techniques reported or discussed do not have universal

application throughout all forested lands in Washington, Oregon, Idaho

and Alaska.  To the contrary, the first and cardinal rule for the solu-

tion of any engineering design problem is to deal with the actual cir-

cumstances at the individual site in question.  As Robert W. Larse has

suggested, "the designer must have a knowledge and understanding of design

criteria and principles, but must be free and have sufficient experience

and ability to design for specific conditions, rather than to apply general-

lized design rules to all situations" (5).

     In the Summary and Recommendations Section of their report on slope

failures in the Idaho Batholith, M. J. Gonsior and R. B. Gardner suggest

a need for a reorientation or philosophical change in engineering approach

as follows:

     "In addition, there appears to be a need for a subtle philosophical
     change in the traditional engineering approach to problem solving


                                 94

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     and design.   Usually, the integrity of a road,  dam,  or any other
     structure is viewed as the primary goal, and thus  natural  processes
     such as erosion,  seepage, and settlement are considered as imposi-
     tions on the structure which must be controlled or withstood.   In-
     stead, the road or structure might better be viewed  as an  imposi-
     tion upon the various natural processes, and location and  design
     might better be oriented toward assuring the continuity of,  or at
     least compensation for changes in, these natural processes.   By
     so reorienting design philosophy not only should the integrity of
     roads and structures be better guaranteed, but  the chances for caus-
     ing undesirable changes in the functioning of natural systems should
     be considerably reduced.  Of course, by changing the question from
     "What are the natural processes which will endanger  the road's in-
     tegrity"? to "How will the road influence natural  processes"?  the
     designer is forced to consider a broader spectrum  of environmental
     factors.  Thus, multidisciplinary cooperation and  teamwork become
     not only desirable, but absolutely essential to the  completion of
     the planners' and designers' work" (6).

     The discussion that follows is in the order that a logging road de-

velops namely:  (l) planning and reconnaissance, (2) design, (3) construc-

tion and (4) maintenance.  These divisions do not imply that an appro-

priate engineering organization for every forest land owner will be simi-

larly structured.  Each owner's engineering staff will  be structured in

accordance with his individual circumstances in terms of  size,  terrain,

policy, ownership, product and goals.  Small landowners may find it

economic to retain consultants or to seek help from  governmental or univer-

sity sources when the need for engineering or other  specialists occurs.

     A good case can be made for the procedure that  assigns to  one indi-

vidual or team the responsibility to deliver a completed  road.   Such a

procedure provides continuity in the planning and reconnaissance, design

and construction phases.  Also, an organization whose personnel policies

result in the maintenance of a stable engineering staff possessing many

years of experience on the land that it manages and/or  harvests has a

great asset when approaching the problem of minimizing  the creation and

transport of sediment.

                                 95

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     Writings on the subject of sediment creation and transport in the



forest are extensive.  A large reservoir of unrecorded knowledge is also



possessed by individual experienced forest engineers.  There are no doubt



many successful techniques of sedimentation control omitted from the



chapters that follow.






                     SUMMARY AND CONCLUSIONS






     There is an abundance of information available on the subject of



minimizing the creation and transport of sediment accruing from logging



haul roads.  Further sources of information are the experiences of indi-



viduals long associated with the design, construction and maintenance of



these roads.



     The value of a thorough planning and reconnaissance program for a




proposed road is emphasized by many authorities.   No amount of design or



construction expertise can recover from an approach based upon inadequate



reconnaissance information.  Field reconnaissance evaluations must in-



clude attention to the potential for mass movements as well as surface



erosion.  In steep terrain, it is likely that the engineering investment



to insure a stable road will be much more exhaustive than on gentle terrain.



     The general approach to design must be the classic engineering ap-




proach of according individual treatment to the individual circumstances



of the site.  Creative design is needed.



     Many mass failures are drainage associated.   Drainage design often



appears to have lacked attention to one or more of the following features.
                                  96

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      1.  Determination of  the  design  flood.



      2.  Evaluation of the potential  for  debris blockage.



      3.  Choice  of stream  crossing method.




      -4.  Attention to  installation requirements at both the design



         and  construction  levels to insure structural integrity.



Minimizing  surface erosion and sediment transport begins with the appro-




priate treatment or design of  slope protection, and continues with the



necessary attention to ditch size, lining, culvert intakes, culvert in-



tegrity and culvert outlets.




      Under  most  conditions vegetative or  other forms of permanent cover



are essential to prevent excessive surface erosion from cut and fill



slopes.  Vegetation establishment should be initiated as soon after soils



disturbance as possible.  Various grass and legume seed mixtures are



suitable for establishment of  vegetation in Region X depending on climatic



and other environmental conditions.  Seeding should be accompanied by



fertilization and re-fertilization as necessary and by watering to main-



tain vegetative vigor.  Mulches, chemical soil stabilizers, or mechanical



measures are necessary to prevent high initial rates of soil loss during



vegetation  establishment and in some cases to aid in vegetation estab-



lishment.




     It is  important to sequence the construction in a manner that affords



the least exposure to storm damage during construction.   Contractual



relationships between owner and road builder should be such that a quick



response can be made by all parties to changed circumstances during con-
                                  97

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struction.  Failure to respond promptly can greatly enhance the potential



for sediment creation and transport.



     New types of construction equipment are needed for the proper and




efficient clearing of steep slopes in a manner that reduces the opportunity



for mixing of clearing slash and organic debris with excavated material.



End haul projects on narrow roads have resulted in increasing unit excava-




tion costs.  New equipment that will produce more yardage at less unit



cost is needed.



     The key to a successful maintenance program is the motivation and



knowledge of maintenance personnel.  Individuals control sediment trans-



port attendant to maintenance operations.



     Occasional slides can be expected along logging roads even with the



best location and design practices.  In some cases, abandoning the road



may be preferable to removing slide debris and correcting the problem.



Where it is necessary to remove slide debris, it should be placed in




selected spoil areas.



     Although inclusion of design criteria for sediment control may in-



crease initial capital outlay, it does not necessarily increase total



annual cost over road life.  There may be offsetting savings in annual



maintenance costs.  Stable cuts and fills and adequate culverts and



bridges are desired by forest owners and users for many reasons other



than sediment control.  Features constructed outside of the roadway



corridor for sediment transport minimization are the most obvious examples




of capital outlay for sediment purposes only.



     When construction is accomplished in accordance with adequate plans



and specifications in a workmanlike manner under strict supervision, the



minimization of sediment creation  and transport may be coincident.





                                  98

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                         RECOMMENDATIONS






     The trend  toward obtaining a thorough field reconnaissance for



 logging roads should be continued and even accelerated.



     Several methodologies (e.g. Universal Soil Loss Equation) have



 been developed  for prediction of soil loss under various conditions.



 However, none have been specifically developed or tested for use in a



 forest environment.  Additional research is required to test the avail-



 able equations  for use on forest logging roads.



     A system of high altitude rain and stream gaging stations, estab-



 lished in advance of logging or road building operations, would be



 helpful to the  determination of mountain stream flows for stream cross-



 ing design purposes.




     Organizations should assign responsibility and authority to exper-




 ienced engineers at the local level for planning and designing the log-



 ging roads.  Personnel policies should support the retention of exper-



 ienced engineers in or near the forests they serve.



     Highway engineering tools, criteria and techniques developed for



 state,  county or municipal roads should not be blindly applied to forest



 roads.



     An equipment research program directed toward the modification



 of current equipment or development of new equipment for excavating



narrow roads in steep terrain is needed.   The goal of the research



 should be relative economy in the earth excavating and loading operation



for end haul projects as compared to the  costs of these operations using



presently available equipment.






                                  99

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             ROUTE PLANNING AND
                 RECONNAISSANCE
     Route Planning and Reconnaissance is regarded by many as the most
important phase of logging haul road development.  It is at the planning
and reconnaissance level that first evaluations of soil erodibility,  the
potential for mass movement, and the potential for sediment transport
must be made.  These evaluations may confirm the proposed road corridor,
cause a change in forest harvest procedure, indicate the need to survey
an alternate corridor or contribute to a no road decision.
     The importance of road reconnaissance is detailed in several refer-
ences.   Crown Zellerbach Corporation's Environmental Guide, Northwest
Timber Operations, states in Chapter V, "Road Building":  "Special
emphasis must be placed on proper road planning, design of cross sections,
and field location to reduce soil erosion problems and consequent stream
siltation and stream blockages" (7).   Larse, in a paper entitled "Preven-
tion and Control of Erosion and Stream Sedimentation from Forest Roads",
emphasized planning and reconnaissance when he stated:  "Road planning and
route selection is perhaps the most important single element of the road
development job" (5).   The U. S. Forest Service Region 6's Recommendation
3.1 from Timber Purchaser Road Construction Audit is:  "Preconstruction
geotechnical investigations, transportation planning,  and construction
inspection on earthwork and drainage  should receive the highest priority
for manpower" (8).  The Siuslaw National Forest's Implementation Plan to
the Region 6 Audit agrees that "the greatest potential for land impacts
from road construction lies in areas  of steep topography and unstable
                              101

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soils" (9).  The Boise National Forest's Erosion Control on Logging



Areas states:  "To a great extent erosion can be prevented by controlling



the location of roads and skidways in relation to the natural drainage,



slopes, and soil conditions" (10).




     In the recommendations contained in Flood Damage In The National



Forest of Region 6, Jack S. Rothacher and Thomas B.  Glazebrook believe



that any procedures designed to minimize unusual weather impacts on soil



must be based on increased knowledge of geomorphic history, climate, hydro-



logy, vegetation, soils and landscape features of the land (ll).  "The



importance of reconnaissance is indicated by the fact that failure to con-



sider all alternates may result in future excessive costs far beyond any



savings effected by not accomplishing a complete reconnaissance" (12).



(Bureau of Land Management Roads Handbook)



     R. D. Forbes in Forestry Handbook provided one estimate of the total



planning and design effort required when he stated:  "The importance of



adequate surveys, and careful planning for road construction justifies engi-



neering costs up to 5% of total cost for low standard while 10$ to 15$ is



reasonable for engineering permanent heavy-duty hauling roads in rough



country" (13).  Any estimate of engineering costs should recognize the in-



dividual circumstances of the project under consideration.



     Neither the competent designer nor the competent road contractor can



economically overcome faults in a road concept that are related to inade-




quate planning and reconnaissance.



     The following discussion of route planning and reconnaissance begins




when the forest land manager has determined that a road is required.  The




manager has made some preliminary decisions about the purpose of the road
                                  102

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 and companion decisions as to the general corridor that is preferable




 from a management viewpoint.  He conveys this information to his engi-




 neering staff for implementation.  Results of the subsequent engineering




 planning-reconnaissance phase may alter the initial management decision.




     The first part of this chapter covers engineering planning aspects




 and the engineer's communication with land management.  The second part




 discusses the field reconnaissance by geotechnical, forest and civil




 engineering personnel.  The last part (third) discusses economic evalua-




 tions.  The chapter is divided in this manner partly for the convenience




 of presentation.  The planning and reconnaissance activities are often




 very interrelated depending upon the type of organization and the nature




 of the road project under study.






                           ROUTE PLANNING






 MANAGEMENT-ENGINEERING DIALOGUE






     After the engineers'  introduction to the Forest Land Manager's road




 requirement, a dialogue often develops between the two parties.   The com-




munication may encompass road standards, intended use, harvest methods




 and road life.   The discussion may result in a program of road feasibility




 studies or simply a direct road reconnaissance and design.




     Initial communications become critical to the road development parti-




 cularly when minimum environmental impact roads,  including sediment mini-




mization,  are required.   In their communications,  both the engineer and




the land manager must attempt to reach a complete  and explicit understand-




ing and avoid communication gaps.  An illustrative case is the China Glen







                                 103

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Road on the Warren Ranger District, Payette National Forest, Idaho.

The road was to serve a salvage timber sale in three fragile water-

shedsnr  Management gave special instructions to minimize watershed

damage.  Road standards had, to some extent, been established by the

forest management and engineering appeared to have accepted these

standards.

     Prior to construction, management reviewed the design documents

and road construction was begun.  However, gaps in their initial com-

munication became evident as is reported by W. S. Hartsog and M. J.

Gonsior.

        "During field inspection, land managers expressed
     concern that the road would have more impact than had
     been anticipated.  They felt that cuts and fills were
     larger than desirable or necessary.  Apparently, they
     could not fully visualize the final product from the
     design sheets, which indicates a need for better com-
     munications" (14).

     The China Glenn Road experience demonstrates the need for com-

munication when roads in ecologically sensitive areas are envisioned.

In some cases (particularly in steep terrain), small soil and geologic

disturbances may result in measurable ecological differences including

the presence of stream siltation.  In these circumstances the responsi-

ble forest engineer continues the dialogue and provides "feed back" to

the forest land manager by evaluating the terrain's in situ  condition.

The engineer will evaluate the terrain for elevation, aspect, soil

strength, ground slope, ground water, geologic formation and precipita-

tion.

     The need for the engineer to evaluate management's decision is
                                 104

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 accentuated by the fact that a large part of the commercial forest



 lands in Region X are located on land that requires a careful assess-



 ment of the road's potential performance.  This assessment should in-



 clude determination as to whether or not existing technology is equal



 to the ambient circumstances within a particular road corridor.






ENGINEER'S  ASSESSMENT OF MANAGEMENT'S  DECISION






     The technological tools available to the engineer to accomplish a



 pre-field  reconnaissance evaluation of a proposed road corridor might



 include his own knowledge of the area, performance of existing roads



 in similar terrain, topographic maps, geology maps, aerial photographs



 and photo  interpretation equipment, soil resource maps and hydrology



 data.  His evaluation should permit him to advise management that a



 preliminary assessment of the proposed road corridor has led to one of



 the following answers:



     1.  There is no chance of constructing a stable road; or



     2.  The road envisioned by management cannot be constructed but



         one of lesser design criteria in terms of width, grade and



         horizontal curvature might be constructed pending confirma-



         tion by field reconnaissance; or



     3.  A road might be constructed into the general area with com-



         panion modification of the harvest procedure; or



     4.  Management's road might be constructed pending confirmation



         by field reconnaissance; or




     5.  Management's road can be constructed with relative ease pending




         confirmation by a brief field reconnaissance; or






                                  105

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     6.  Managements'  road cannot be constructed with the allocated



         dollar amount.






State of the Art Techniques






     Within the past few years, some forest land owners have become



keenly aware of the hazards of sediment production.   As a result of



this awareness, a number of land management devices  which attempt to



evaluate the timber production land base have been developed.  Several



of these devices focus on the effect of unstable terrain on forest land




management practices including road construction.  These land evalua-



tion tools are of basically two orders, regional to sub-regional (i.e.



Pacific Northwest divided into homogenous land form unit like the North-



west Olympic Peninsula), sub-regional to local (i.e. Northwest Olympic



Peninsula land form units of 10 acres or larger homogenous units).  The



following paragraphs illustrate techniques which have been developed



by Region X researchers and practitioners to critique sensitive terrain.



     1.  The Forest Residue Type Areas Map produced by the U. S.



         Forest Service for Region 6 is an example of the larger



         scale representation.  This information shows geomorphic pro-



         vinces, timber species associations and geomorphic sub-provinces,



         The smallest mapping unit is approximately 10 miles square (15).



     2.  The U. S. Forest Service's soil resource inventory for Forest



         Service Region 6 and other regions represents the next level



         of forest land identification.  "Soils have been defined and




         mapped at an  intensity sufficient for broad management  inter-




         pretations which can be used to develop resource management



         policies" (16).  In addition to these uses, forest  soils are






                                 106

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    rated as to their potential erosion class, very slight, slight,



    moderate, severe and very severe.  "The land manager can use



    this information to determine which areas will need special ero-



    sion protective measures.  These will need to be developed on



    a site by site basis" (17).  These maps serve transportation



    planning needs as well.  "Conditions and problems can be met or



    avoided based on information such as landscape stability, soil



    depth, soil drainage and/or bedrock type and competency" (17).



3.  The Bureau of Land Management, Oregon State Office, is accom-



    plishing intensive inventories of its western Oregon lands.



    The objective is to provide the manager with detailed, in



    place information about timber production sites for which he



    is responsible (18).  The intensive inventories deal with the



    total land mass by separating the land base into various cate-



    gories of potential forest production.  One category, designated



    as fragile, pertains to adverse soil and geologic conditions.



    Fragile sites are defined by slope gradient, ground water,  geo-



    logic material (bedrock) and soil strength.  Appendix 5 to



    Bureau of Land Management Manual Supplement No. 5250 - "Inten-



    sive Inventories", dated February 7, 1974, deals with procedures



    for identifying fragile sites.  Guide to Reduce Road Failures in



    Western Oregon by Burroughs, Chalfant, and Townsend includes a



    general outline of Western Oregon geology, and discusses basic



    slope stability, and techniques for constructing stable roads on




    specific geologic materials and soils (19).






                             107

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4.  The Siuslaw National Forest has developed two schemes for eval-



    uating terrain readability.




         a.  "Workload Analysis - Geo-technical Investigation



             for Timber Sale Roads" (9).



         b.  "A Proposed Method of Slope  Stability Analysis,"



             Jennings and Harper.




    The work load analysis uses a factor  "P" which expresses a



    percent probability that a given section of road location will



    require a given level of geotechnical investigation.   Figure



    19, taken from Appendix E of the Siuslaw National Forest



    Implementation Plan illustrates the use of the "P" factor.



         The Proposed Method of Slope Stability Analysis  attempts



    to answer many forest land administrators and planners who have



    expressed a need for a quantitative evaluation system to rate



    slope stability.  This report proposes a slope evaluation sys-



    tem based on a soil mechanics safety  factor formula named "The



    Stability Index (Si)".  It is intended to describe the general



    slope stability of a soil mapping unit, separating only the



    effect of slope.  It is not to be used to evaluate on-site sta-



    bility for specified projects 'Taut with additional input it could




    be used as a starting point for project site analysis" (20).



5.  "Highway Cut and Fill Slope Design Guide Based on Engineering



    Properties of Soils and Rock" by Larry G. Hendrickson and John



    W. Lund is a valuable design guide for specifying cut and embank-



    ment slopes (21).  This design approach attempts to reduce the





                            108

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                                        60T
O

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    use of intuitive techniques and to substitute a more rational

    approach.  The procedure uses soil strength properties together

    with flatter slopes as cut heights increase.  This work is in-

    corporated into the U. S. Forest Service's Transportation

    Engineering Handbook for Region 6 as Supplement No. 19, dated

    February 1973.  The supplement digest explains the Design Guide

    as follows:

         "Incorporates slope design guide.   This is a guide
         which provides general values or recommendations
         for cut and fill slope ratios.   Data needed to use
         the guide are soil classifications, general field
         conditions in respect to density and moisture, and
         height of cut or fill.

         The recommendations given must be modified to fit
         local conditions and experiences" (22).

6.   Douglas N. Swanston and others of the U. S.  Forest Service

    developed a pilot program for determining landslide potential

    in glaciated valleys of southeastern Alaska.  This development

    was in response to investigations which had shown erosion to

    be a predominate problem in southeast Alaska.

         Land stratification techniques were- used to classify

    potential landslide hazard.  Data on land features were

    characterized by "accurate location and distribution of all

    active and potential landslides and snowslides and the estimated

    or probable major variations in a slope stability characteristics

    from one location to the next within the investigated area".

    From this information a hazard rating system was devised to

    stratify land zones (23).


                            110

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              Their experience with the southeast Alaska's steep slopes

         with shallow coarse grained soils lead them to use three clas-

         sifications.

              a.  "A slope above 36° is highly unstable even under
                  the most favorable of natural conditions.

              b.  Slopes between 26° and 36° may or may not be stable
                  depending on local variations in basic soil charac-
                  teristics, soil moisture content and distribution,
                  vegetation cover, and slope.

              c.  Slopes below 26° (49$) were considered stable
                  although local steep, hazardous areas not picked
                  up in the initial survey may exist, and opera-
                  tions on them should be governed by the rules
                  for more unstable areas."

              Swanston emphasizes the many natural unstable slope condi-

         tions in southeastern Alaska and observes that man's activities

         will aggravate them.  He believes that the land manager must

         decide whether "to accept the consequences of logging over

         steepened slopes or to control the effects of these activities

         in order to minimize mass movements" (24).  He suggests that

         control can be accomplished by direct methods of slope stabili-

         zation or by avoiding areas of known or expected instability.


 Roads and Harvest Method Relationships


     There is a general trend in forest land management toward a closer

coordination of road planning with harvest 'methods.  One of the factors

supporting this trend is the realization that past practices have some-

times resulted in haphazard road patterns resulting in more total road

mileage than necessary.  Minimizing the road mileage is also a way to
                                  111

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minimize the need to deal with the sediment creation and transport



problem.




     Recognition of the problems attendant to over roading is not new.



In 1956, the Boise National Forest's guidelines for erosion control



reported a tendency for an excess of roads with the increased use of




heavy construction equipment, "especially if the construction chance is



easy."  This publication further stated:  "Too many roads within an area



completely destroy the protective soil mantle" (10).




     Fredriksen studied erosion and sediment resulting from timber har-



vest and road construction in watersheds within the H. J. Andrews Experi-




mental Forest (2).  A watershed harvested by  clearcutting using Skyline



logging without roads yielded less sediment than a watershed harvest



by patch  clearcutting, high lead logging and parallel logging roads.



     Although harvest method - road relationships are not exclusively



the forest engineers domain, nor are they exclusively pertinent to the



subject of sediment, serious attention to these relationships is be-



lieved to be an important part of the engineer's initial discussions with



the land manager.  The engineers pre-field reconnaissance response to



the land manager about the engineering feasibility of a proposed road may



appropriately include a response to management's assumed logging method



as previously mentioned.  Alternately, the engineer may be asked to




assist the land manager determining what harvest method is compatible to



the type and location of road that can be constructed in the proposed



corridor.





                                   112

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     A detailed discussion of the road-harvest method relationship is




beyond the scope of this report.  Harvest systems and road location,



density and standards are interrelated.  As neither the harvest system




nor the road network are independent of each other, both must be consi-




dered in the evaluation of total system impacts.  Knowledge of the har-




vest method and its effect on road location, width and alignment is of




vital importance in defining the scope of the field reconnaissance.






CONCLUSIONS






     After the engineer's report to the land manager, a mutually agree-




able definition for the road reconnaissance should be ideally established.




Since a "no road" decision is complicated in marginal terrain, a field




reconnaissance to affirm this decision may be necessary.




     A specific understanding of management objectives is a need that




was emphasized in Recommendation 6.1 of the U. S. Forest Service Region 6




Road Audit (8).  The Siuslaw National Forest Implementation Plan urges




detailed management inputs including trade-offs considered, allowable




impacts on road geometry that are acceptable to attain an objective and




the inclusion of "realistic confidence levels expected in the designer"(9).










                       ROUTE RECONNAISSANCE






     Route reconnaissance is the examination of the entire area surround-




ing the proposed project with the intent to segregate routes on their




relative merits of economics, service and ecological impacts.  The tal-




ents appropriately involved in a reconnaissance for a particular project




will vary with the scope of the proposed road, the relative sensitivity of






                                  113

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the terrain, the knowledge and experience of personnel and the amount of




data already available about the proposed corridor.



     Larse points out that "all too frequently the location of a specific



road is a one-man effort with little consideration or recognition of al-



ternative opportunities, watershed values, land form or soil character-



istics and stability, or other environmental conditions" (5).   A recon-




naissance team might consist of a hydrologist, soil scientist  or soils



engineer, geologist, landscape architect, forester, forest engineer,



civil engineer, watershed specialist, biologist and others.  The discip-



lines listed above might be those assembled for a major undertaking in



highly sensitive terrain about which little applicable data is available.



     Members of a reconnaissance team whose duties would include obser-



vations for and the gathering of data to determine potential problems



of sediment creation and transport are the geologist and/or soils engi-



neer, the forest engineer and the civil engineer.  The depth of investiga-



tion necessary for these disciplines cannot be generalized in the abstract



without specific knowledge of the actual site conditions for a proposed



road.  As pointed out in "State of the Art Techniques" in this Chapter,



the Siuslaw National Forest has a procedure for determining the depth of



geo-technical investigation required for a given road location.



     As the introduction to this Chapter emphasized, an adequate field




reconnaissance is of great importance when the goal of sediment minimi-



zation is a part of logging road performance  criteria.  Historically,



sedimentation problems  have been related to the following  oversights or




errors.





                                  114

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     1.  Inadequate geo-technical information.




     2.  Lack of engineering input.




     3.  Application of rigid rules regarding horizontal curvature




         and vertical gradients.




     4.  Over-roading or misplaced roads due to a lack of or a poor




         land management and transportation plan.




     5.  Road locations that support an inappropriate harvest procedure.




     The discussion that follows is divided into three parts:  (l)




factors affecting surface erosion, (2) erosion and mass wasting consi-




derations, and (3) civil and forest engineering reconnaissance.






FACTORS AFFECTING SURFACE EROSION






     Surface erosion includes sheet erosion and channel erosion.   Sheet




erosion, including rill erosion, involves the detachment and removal of




soil particles by overland runoff, while channel erosion involves removal




and transport of material by concentrated flow.  The concentrated flows




may be contained in large mainstem channels, small tributary drainage



channels, or road ditches (25).






     Many factors with often complex interrelationships are involved in




surface erosion.   The primary factors involve precipitation characteristics,




soil characteristics, topography, and cover conditions (26, 27, 28,  29,




30).






     Precipitation intensity and amount affect both sheet and channel




erosion.  The higher the rainfall intensity or snowmelt, the greater the




                                  115

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detachment and transport of soil particles through sheet erosion and the



greater the rate of runoff which is reflected in increased channel



flows.  As runoff discharges increase, velocities likewise increase.






     The erodibility of a particular soil depends upon its resistance to



detachment and, once detached to its resistance to transport.  The



resistance to detachment is primarily controlled by particle-size and




aggregation, while the resistance to transport is primarily governed by



particle-size.  Clays, for example, have very small particle-size and



are easily transported by water, but are not easily detached because of



high aggregation.  Coarse sands or gravels are noncohesive, but are not



easily detached or transported because of much larger particle-size.



Silts, including fine sands, have relatively small particle-size, although



not as small as clays, and are generally relatively easily detached and




easily transported, thus making them most vulnerable to erosion.  Silts



become less erodible as either the sand and gravel or the clay fractions



increase.  Also, for a given increment of silt, increases in the clay-



to-sand ratio decrease the erodibility (31, 32).  Adverse effects upon



water quality, however, may be increased with increasing clay content



because of the extremely poor settling characteristics of clay thus



causing turbidity.






     The capability of runoff to detach and transport soil material



increases rapidly with increases in runoff velocity which is controlled




by topography, among other factors (33)-  Theoretically, doubling



velocity enables water to move particles 6/4 times larger, carry 32 times



more material in suspension, and increase the erosive power 4 times (25).



                                 116

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 Runoff velocity increases as  the runoff rate increases,  as the  flow




 concentrates  (often because of increased slope  length),  or as the  slope




 steepens.   Increasing  the steepness  of a slope  from 10 percent  to  -40




 percent,  for  example,  doubles the flow velocity.






     Sheet  erosion is  greatly affected by cover conditions.  Raindrops




 striking  bare soil act like minature bombs to break up soil  aggregates




 and  splatter  soil  particles as much  as 2 feet into  the air.  Raindrops




 also compact  exposed soil surfaces resulting in increased  rates of




 surface runoff.  Some  conception of  the striking force can be envisioned




 from the  fact that raindrops  strike  the ground  at velocities of about 30




 feet per  second  and 1  inch of water  over an acre of area weighs more




 than 110  tons.   Sheet  erosion is reduced by maintenance  of a dense




 ground cover.  Vegetation is  the most  effective means  of providing this




 cover.  Vegetation acts to absorb and  disperse  raindrop  impact  and




 stabilizes  the soil surface with a dense mat of roots.   Mulches and




 other  forms of ground  cover can also be  quite effective  (34, 35).






     Channel  erosion is also  affected  by cover  conditions, both in the




 channel and in the  tributary  drainage  area.  Poor areal  cover not  only




 results in high rates  of  sheet  erosion but  also results  in high channel




 flow.  Noncohesive, fine-grained  soils  such as  silts and fine sands




 erode readily when  channel velocities  exceed 2  feet per  second.   Good




grass cover in the  channel may  enable more  than doubling of these




velocities before serious erosion develops.  Riprap cover  or other means




of channel protection may protect the  channel from scour for velocities




up to 10 feet per second or more (25).




                                 117

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     The relationships among the principal factors controlling soil




erosion, notably sheet erosion,  have been embodied in several somewhat




similar predictive equations (25, 26, 27).  Most of the equations




presently available have been developed for cropland areas.   Of




these, the "Universal Soil Loss Equation" for predicting sheet




erosion, as presented by Wischmeier and Smith in USDA-ARS Argriculture




Handbook 282 (26), has gained the most widespread acceptance.  The




available predictive methodologies still fall far short of accurate




prediction of soil erosion or resultant downgradient sediment production




in a forested environment.  Additional research is needed to test the




available equations for use on forest logging roads, or, if necessary,




for development of new prediction techniques.






SURFACE EROSION AND MASS WASTING CONSIDERATIONS






     Roads seriously impact the hydrologic functioning of watersheds.




In many areas of highly decomposed granitic soil, 90 percent of the




increased sediment caused by use of the forests has been attributed to




roads (36).  Higher runoff rates, increased surface erosion, and mass




wasting account for these increases.  Much of the soil movement can be




avoided by proper road location and design.  Adequate field and office




investigative work is necessary to assure that the  essential information




needed for selection of the best route and proper road design is available.






      During the planning process discussed in a previous section, the




need  for the road is established and road termini and intermediate




points are defined resulting in  delineation of a general road corridor(s).






                                  118

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Other  controlling design parameters,  such as  type  and volume  of  anti-




cipated use, type of road,  and  any  special features  required,  are  also




defined.  However, prior to any actual  design work,  reconnaissance




studies must be  conducted to locate the best  road  alignment and  gather




information needed for design of the  road itself and associated  drainage,




erosion, mass wasting, and  other control  measures.   The  source of  the




reconnaissance information  can  range  from office maps and reports  to




detailed investigative programs involving field explorations  and labora-




tory analyses.






     A broad-based team of  technical  specialists should  evaluate the




available information to develop a  road design that  best suits the




intended purposes while also minimizing economic and environmental




costs.  However, because of the scope of  this study, only those  factors




affecting road performance  with regard  to surface  erosion and  mass




wasting as they  affect water quality  are  included  in this report.  Some




of the information that should  be considered  to guard against  stream




pollution resulting from surface erosion  and  mass wasting includes soil




texture and aggregation; subsurface soil  strength, depth, and  other soil




or rock conditions; slope lengths,  steepness  and aspect; existing  surface




erosion and mass movement behavior  along  the  route;  precipitation  and




streamflow characteristics;  groundwater conditions;  surface drainage




network; soil fertility and other conditions  affecting vegetation




establishment;  and up-gradient  and  down-gradient slope vegetation




patterns (36).
                                 119

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     The importance of the reconnaissance investigation cannot be over-




emphasized.  It is during the reconnaissance work that the major decisions




are made.  Once the road is located and constructed,  mistakes are often




difficult or impossible to correct later on.  Failure to do an adequate




job of reconnaissance can easily result in future construction, main-




tenance, transportation, and environmental costs far in excess of any




savings realized from an incomplete or inadequate reconnaissance (12).






Aids






     Aids are of primary value during the planning phase.  However, use




should be made of all available aids, including topographic maps, geologic




and soils maps and reports, aerial photographs, and others during the




reconnaissance investigations to gain an overall perspective of the




route or routes being considered and to obtain any detailed information




they may provide.  During these investigations, aids should only be used




as supplements, however, and not substitutes for field investigations.




As a minimum for simple cases where these aids offer sufficient information




for design purposes, their accuracy should be field checked.  Some of




the available aids and potential applications are described in the




following sections.






     Aerial photographs.  Aerial photographs are particularly valuable




in the planning stage for gaining an overall feel for a general area  and




detecting differences between local areas that are important to route




corridor selection.  However, they are also of considerable value  in




final route selection and design during the reconnaissance investigation.




Aerial photographs of at least one usable scale are available  for most




                                 120

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 areas,  and in some  areas more  than one  scale  is  available.  Many photos




 are  available in stereoscopic  pairs permitting viewing  in three  dimen-




 sional  perspective.   Land  forms, vegetation,  or  geologic  and hydrologic




 features  are  easily identifiable from such photographs.






     Small-scale aerial photographs provide a broad perspective  of  an




 area.   Whole  landscapes can be surveyed,  enabling  study of drainage




 networks,  geologic  features and land  forms, and  vegetation patterns.




 Mass movements,  particularly large failures,  are easier to detect.




 Rotational movements  are often indicated  by arc-shape bedrock exposures




 accompanied by uneven lands downslope or  variations or  abrupt changes in




 vegetative patterns.  Avalanche activity  can  be  similarly identified by




 abrupt  changes in vegetative patterns perpendicular to  the  ridge  system.




 Large features of this nature  are  often much  easier to  identify from




 such photographs than through  use  of other aids  or on-ground observations.






     Large-scale aerial photographs can be used  to refine  interpretations




made from  the  small-scale photos as well  as enable more detailed  inferences




 of drainage, geologic, topographic, vegetative,  and other factors.




 Geologic bedrock types can  often be identified and some degree of accuracy




 can be developed regarding  the  fracturing and jointing pattern of a




particular bedrock type.  The  extent of talus, alluvial, and other




deposits can usually be identified.  Slope gradients can be determined




with some degree of accuracy,  and stream channel and other drainage




characteristics can be studied.  Vegetative patterns and types can be




identified.  Other interpretations, such as soil types,  can often be
                                 121

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made based upon interaction of geologic and land form characteristics,




vegetation, color, and other factors.  Small-scale mass movement or



erosion activity can often be identified.






     Topographic Maps.  Topographic maps of various scales are available



for most areas.  Such maps, particularly the 7J- and 15-minute series,



are quite useful for road location and design purposes (37).  Infor-



mation on slope gradients and other topographic features can generally




be obtained with a reasonable degree of accuracy, particularly if over-



story vegetation was not dense at the time of photography for mapping.



Geologic inferences, including landform, slope steepness and irregularity,



arrangement and incision of drainage networks, and other features can be



made from topographic information.  Topographic maps provide considerable



information on stream systems such as gradients and channel sizes in



easily obtainable form.  Topographic maps are quite useful as base maps




and provide an easily available source of gradient information for trial




road alignments.





     Soil Surveys.  Numerous types of soils are exposed during road



construction in EPA, Region X.  They are formed from many different



parent materials including glacial till, alluvial deposits, and granite.



These soil materials all have various unfavorable physical and chemical



properties that affect road performance, stability against surface



erosion and mass wasting, and revegetation.  Soil or geologic character-



istics and related topographic conditions that may affect subsequent



road behavior  include  steep slopes, aspect, shallowness to rock or other



restrictive layers, unfavorable pH, low  fertility, fine soil texture




                                  122

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and low aggregation, low permeability, high groundwater table, high




shrink-swell potential, massive disturbance as a result of previous




slide activity, low strength characteristics, and high compressibility.






     Soil surveys furnish considerable information on the extent of




these interacting features.  Such surveys are generally compiled as a




single unit for large areas such as counties or national forests.  This




provides a wealth of information on a broad scale that is well suited to




route selection, as well as for general guidance in road design.  Soil




surveys are made and published by a variety of governmental agencies and




private organizations but mostly by the federal government.  The Soil




Conservation Service has published detailed soil surveys for many counties




within EPA, Region X, and the Forest Service has published soil surveys




for many of the national forests (16, 17).  New surveys are continually




being developed by these agencies and older surveys are continually




updated.  The Weyerhaeuser Company has recently completed and published




an extensive soil survey of their land holdings as well as of contiguous




adjacent lands.






     In addition to providing information on many of the individual soil




properties, most surveys also provide considerable interpretative




information on soil suitability for various uses, including limitations




on uses.  Such ratings may include suitability for road location and




construction; potential for surface erosion; susceptibility to cut




or fill bank mass movement,  sloughing, or raveling; limitations on cut




and fill slope seeding;  suitability for various types of vegetation




establishment; and numerous other behavioral characteristics under




various uses.




                                 123

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     Geologic Maps.  Geologic maps or reports of various degrees of




detail are available for many areas.  The maps range in scale from state




or areawide to much smaller areas, such as portions of counties or 7|-




or 15-minute topographic quadrangles.  Depending upon the degree of




detail, geologic maps may include information on topography, descrip-




tions and extent of surface outcrop materials, and strike and dip of




formations.  Such maps may also include geologic hazards such as faults,




degree of slope, flood-prone areas, high groundwater table areas, landslide




topography, and areas susceptible to various types of surface erosion.






     Other Aids.  Several other less used but often equally important




aids are of value.  These include precipitation intensity-duration maps




(38, 39), vegetation maps, hydrographic studies, or other general or




detailed reports available for the study area or similar areas.






Field Reconnaissance






     Field reconnaissance is an essential step in any road location or




design study.  In all but the simplest cases where the designer has



access to proven aids and is thoroughly familiar with an area, a field




reconnaissance should be made before final route location or design.




The purpose of the field reconnaisssance is to confirm inferences made




from other information sources and to gather otherwise unavailable or




more detailed information needed for either road location or design.




Only in rare cases will published information be detailed and accurate




enough to be suitable for final design purposes.

-------
     During field reconnaissance, the applicable published information




on maps and aerial photographs should be used.  These are valuable in




determining the location of control points, and are generally reliable




for use as base maps for field layout work.






     The depth of the field reconnaissance is dependent upon the amount




of data already available, the importance of the road, and the magnitude




of the impacts the road is expected to generate.  Generally, more than




one field reconnaissance trip will be necessary.  These field investi-




gations may be phased and include a preliminary field reconnaissance and




soil survey of the corridor by a team of experienced specialists.  The




team should include an experienced soils engineer, engineering geologist,




or similar specialist.  The preliminary reconnaissance and soils'.'Survey




should establish the surface erosion and mass wasting potential within




the corridor and areas adjacent to the corridor and potential access of




eroded or wasted materials to streams.  This preliminary work should




also include delineating areas of potential hazard and, where possible,




outlining alternate routes to avoid the hazards.






     The next phase of work should consist of detailed investigations of




the hazard areas and possible alternate routes.  The detailed investi-




gation may include test pits, borings, undisturbed sampling for strength




testing, installation of piezometers to obtain valid water table infor-




mation, and in some cases installation of slope indicators to determine




the degree of mass movement.
                                  125

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     Many factors must be considered and properly evaluated during field



reconnaissance surveys if surface erosion and mass movement are to be



minimized.  The factors primarily include surface and subsurface soil



and geologic conditions; topography, including slope steepness, length,



and aspect; precipitation; groundwater conditions; and vegetation.  How



each of these and other factors affects sediment contribution to streams



due to surface erosion and mass wasting will be discussed in the following



sections.






     Surface Evasion.  Numerous factors affect the potential for soil



erosion from forest roads and contribution of such sediments to streams.



These factors, which were discussed in a previous section, primarily




include soil texture, aggregation, and other intrinsic properties;



topographic factors such as slope steepness, length and aspect; nearness




of the road to the stream system; precipitation amounts, types and



severity; and up-gradient and down-gradient vegetation.  Roadway design,



including slope protection and drainage provisions, can also have a



significant influence.






     By far the most important factor influencing surface soil erosion



is soil texture and aggregation, although several other characteristics



are involved (32).  Silt-size particles are the most erodible, and the



erosion potential decreases as the percentage of sand or larger and




clay-size particles increases.  Clay-size particles, however, have more



adverse effects upon water quality because of their extremely poor



settling characteristics.
                                 126

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      Detailed evaluation of the soil texture,  aggregation,  and other




 characteristics  affecting erosion would be  somewhat  difficult  in the




 field.   However,  in many cases  experienced  field personnel  could make a




 reasonably accurate estimate of the  necessary  information by visual




 inspection and by use  of shake,  pat,  kneading,  and other  types of simple




 field tests.   One such field classification guide to estimate  inherent




 soil  erosion  potential is shown in Table 4  (40).  This  guide is based,




 in part,  on the  Unified Soil Classification System.   This system is




 presented in  Table 5 (41) along with field  identification procedures and




 several  simple tests used in classifying soils  according  to  the system.






      There are numerous procedures which may be used during  a  field




 reconnaissance to obtain soil samples for textural identification.




 Among these are  small  hand  augers.   With the use  of  extensions,  these




 augers can be  used to  obtain small samples  from depths  of 3  to  15  feet.




 However,  these augers  are of limited use in soils containing large




 percentages of gravel  or  in bedrock.  Shallow samples for textural




 identification can be  obtained  from hand-dug pits in  coarser grained




 soils.  Also,  information on shallow as  well as deeper  soil strata can




 be obtained from natural  or  man-made exposures within or  near the




 corridor and these soil conditions correlated with those  along  the



proposed route.






     Other  soil factors besides those strictly influencing surface




erosion and mass wasting  should also be  investigated during the field




reconnaissance.  These include moisture regime and fertility.  They are




of value in planning the revegetation program.





                                 127

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             TABLE 4.   GUIDE FOR PLACING COMMON SOIL AND GEOLOGIC TYPES INTO EROSION CLASSES  (40)
00
Erosion
Class I
Erosion
Index 10
SM-

-o
0)
•H
<3 ML
•l~l
•0
3
w
(D
i
-p 03
0) p)
H 0
i — 1 C_3
•H
O i — 1
W -H
O
T3 CO
cd €
9 CO
II III IV
20 30 40
SM Silt (Un- Silt (Con-
consoli- solidated )
dated )(B) (B)

ML OL OL



MH MH
V
50
Silty
clay
loam( A )

Silty
clay(A)


Clay,
VI
60
Clay
loam
(A)

Silty
loam
(A,B)

varying
cohesiveness &


CL







Sandy
clay(B)


SC, GM
OH, CH
(A)

Sandy
clay
(B)

CH, GM

VII VIII IX
70 80 90
Loamy Coarse Fine
sand sand gravel
(c) (c) (c)

Sandy SW
loam SP
(B)

with type,
compaction


Sand
(B)


GC

X
100
Rock
(c)


Cobble
(c)


Gravel
(c)


GW, GP





     NOTE:  (A) indicates nonporous materials;  (B) indicates moderately porous materials;  (C)  indicates highly
            porous materials.

    — SM, ML, etc. refer to the Unified Soil Classification System.

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                                                            TABLE 5  UNIFIED SOIL CLASSIFICATION
                                                         (Including Identification and. Description_)_
Major Divisions
1
Coarse-grained Soils
More than half of material is larger than No. 200
sieve size.
mallest particle visible to the naked eye.
Fine-grained Soils
More than half of material is smaller than No . 200
sieve size.
The No. 200 sieve size is about the s
2
Sands Gravels
More than half of coarse More than half of coarse
fraction is samller than fraction is larger than
No. 4 sieve size. No. 1+ sieve size.
(For visual classification, the 1/4 in. size may he used as
equivalent to the No. 4 sieve size)
Sands with Gravels with
Fines Clean Sands Fines Clean Gravels
(Appreciable (Little or (Appreciable (Little or
amount no fines ) amount no fines )
of fines) of fines)
>> -P O
3 |g
T) £i
d tj +>
& -3 »
ra o< en
S 33
3
co o
>i -p ir\
H ^ fi
o -H a)
H X
-a +=
C T3
aj -H FH
-P -H 03
iH i-^l 
•H FH
W hO
Group
Symbols Typical Names
3 4
GW i Well-graded gravels, gravel-sand mix-
tures, little or no fines.
GP
GM
GC
SW
SP
SM
sc

ML
CL
OL
MH
CH
OH
Highly Organic Soils Pt
Poorly-graded gravels, gravel-sand mix-
tures, little or no fines.
Silty gravels, gravel-sand-silt mixtures.
Clayey gravels, gravel-sand-clay mix-
tures.
Well-graded sands, gravelly sands, little
or no fines .
Poorly-graded sands, gravelly sands,
little or no fines.
Silty sands, sand-silt mixtures.
Clayey sands, sand-clay mixtures

Inorganic silts and very fine sands, rock
flour, silty or clayey fine sands or
clayey silts with slight plasticity.
Inorganic clays of low to modiura plas-
ticity, gravelly clays, sandy clays,
silty clays, lean clays.
Organic silts and organic silty clays of
low plasticity.
Inorganic silts, micaceous or diatoma-
ceous fine sandy or silty soils, elastic
silts.
Inorganic clays of high plasticity, fat
clays .
Organic clays of medium to high plas-
ticity, organic silts .
Peat and other highly organic soils.
Field Identification Procedures
(Excluding particles larger than 3 inches
and basing fractions on estimated weights)
5
Wide range in grain sizes and substantial
amounts of all intermediate particle sizes.
Predominantly one size or a range of sizes
with some intermediate sizes missing.
Nonplastic fines or fines with low plasticity.
(for identification procedures see ML below)
Plastic fines (for identification procedures
see CL below) .
Wide range in grain sizes and substantial
amounts of all intermediate partical sizes.
Predominantly one size or a range of sizes
with some intermediate sizes missing.
Nonplastic fines or fines with low plasticity.
(for identification procedures see ML below).
Plastic fines (for identification procedures
see CL below).
Identification Procedures
on Fraction Smaller than No. 40 Sieve Size
Dry Strength Dilatancy Toughness
( Crushing ( Reaction ( Consistency
characteristics) to shaking) near PL)
None to slight Quick to slow None
Medium to high None to ver^ Medium
slow
Slight to Slow Slight
medium
Slight to Slow to none Slight to
medium medium
High to very None High
high
Medium to high N°ne to ve™ S1j-?ht to
sl ow mprhnm
Readily identified by color, odor, spongy feel
and frequently by fibrous texture.
(l) Boundary classifications: Soils possessing characteristics of two  groups  are designated by coml
                                                                                                ib mat ions of group symbols.
                                                                                                      Source:  Reference 41.
                                                                        129

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     Topographical considerations are very important in road location.



Among these are slope steepness, slope length, slope aspect, and near-



ness to stream channels.






     Roads should be located in stable areas well away from streams in



order to minimize stream sedimentation.  Routes through steep narrow



canyons; slide areas; through steep, naturally dissected terrain;




through marshes or wet meadows; through ponds; or along natural drainage




channels should be avoided.  Where it is impractical to avoid any of



these conditions, corrective stabilization measures should be incorporated



into the road design.  It is particularly important that road locations



be fitted to the topography so that minimum alterations of natural



conditions are necessary (4-2).






     Valley bottoms have the advantages of low gradient, good alignment,



and little earth movement.  Disadvantages are flood hazard, number of




bridge crossings, and proximity to stream channels.  Because of the near



proximity to streams, erosion or mass failures are much more likely to



result in stream sedimentation than from roads along more distant



alignments.  Wide valley bottoms are good routes if stream crossings are



few and roads are located away from stream channels.  Roads in or



adjacent to stream channels should be avoided.  Roads should be located



far enough away to prevent transport of sediment into stream channels




(43).





     Roads in valley bottoms should be positioned on the transition



between the toe slope and terrace to protect the road slopes from flood



erosion and allow road drainage structures to function better and discharge




                                 130

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less turbid water into live streams.  However, road location in these




areas should be avoided if it involves undercutting old slides or land-




flows.  Any stream crossings required should be selected with particular




care to minimize channel disturbance, minimize approach cuts and fills,




and produce as little disturbance as possible of natural stream flow.




Valley bottoms should not be roaded where the only choice is encroach-




ment on the stream (44).






     Hillside routes have the advantage of being located away from




streams which eliminates flood and stream damage, and intervening




undisturbed vegetation acts as a barrier to sediment transport.  Dis-




advantages are higher grades, more excavation, longer slopes, poor




alignment from following grade contours, and cut banks that expose soil




to erosion (43).  When locating roads along side hill routes, benches




and the flatter transitional slopes should be used if they are stable.




Steep, unstable, dissected slopes, particularly in areas of deep plastic




soils or weathered or decomposed rock formations, should be avoided




because of potential mass stability problems (44).






     Ridge routes have the advantages of good drainage, less excavation,




and fair grades (43).  Other advantages include practically nonexistent




up-gradient slopes and large expanses of undisturbed vegetation or




logging slash to act as buffer strips for protection against stream




sedimentation.  Disadvantages are poor alignment in some areas because




of excessive dissection of the ridges, and secondary roads that may have




adverse hauling grades and greater total road mileage (43).  Ridgetop
                                 131

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roads should be located to avoid headwalls at the source of tributary


drainages.  These are often extremely unstable slopes,  and any erosion


or slope failure will flow directly into live streams (44).



     Another locational characteristic, aspect, also has some influence


on soil stability.  However, aspect influences the functional character-


istics of forest roads more than it does their geometric design and


stability.  North-facing slopes retain snow and ice for longer periods


than south-facing slopes (40).  However, Renner's (45) study on the


Boise River watershed showed that erosion differed sharply according to


exposure.  Soils on south exposures eroded most severely.



     Packer and Christensen's (46) study also showed that erosion


rates are higher on south-facing slopes.  This was attributed to the


loosening of the soil by frost heaving.  Also, south and west slopes


in many areas are considerably less densely vegetated than north and


east slopes.  Runoff and sediment trapping characteristics are greatly


influenced by. this.  Aspect also helps determine the degree of success


or failure in reestablishment of vegetative cover after disruption by


road construction.



     During the field reconnaissance, vegetation along the proposed


route should be surveyed.  Vegetation along this route is an indicator


of other  factors, such as soil fertility and moisture regime, but most


important is its effect on retarding runoff both upslope and downslope


of the road prism.  Upslope vegetation and ground litter can have a


significant effect on the amount of water reaching the road prism.  Long


unimpeded, up-gradient slopes with poor infiltration characteristics


can contribute large quantities of overland flow causing erosion of


the road  prism.
                                132

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      Probably more important than upslope vegetation is the vegetative




 and ground cover downslope of the road prism.   Downslope vegetative




 cover can retard overland runoff and discharges from cross drains and




 other road drainage structures causing suspended sediments to be settled




 out before reaching stream systems.   Several investigators,  including




 Trimble  and Sartz and Packer,  have studied the  buffering and filtering




 performance of vegetation strips.   Packer's investigative work was




 particularly comprehensive as to the individual parameters affecting




 buffer strip performance.   Packer found that obstructions such as rocks,




 stumps,  and herbaceous vegetation and trees,  and numerous locational and




 design factors such as amount of aggregates in  the  soil,  amount of




 disturbed slope,  cross drain spacing,  and distance  to  the first obstruc-




 tion,  all influenced buffer strip performance.   More detailed information




 on  factors affecting buffer strip performance is contained in a following




 section.   All of  these factors  should be  considered during field recon-




 naissance,  especially during the road location  work, to  ensure that




 adequate  buffering  is  provided  between roads and stream  systems.






     Mass  Wasting.   The most common  and perhaps the most  significant




 erosion from forest  roads  is mass movement.  This is caused by under-




 cutting unstable  slopes, improper  embankment construction, wasting on




 steep  slopes, and drainage  system failures  (44).  Some of  the  factors




 affecting mass wasting which should be  determined during the recon-




naissance are cross  slope angles; soil  texture,  depth, and in  situ




 strength; groundwater  conditions; and  identification of old, existing,




and potential future unstable areas.  These should be investigated, not




only within the corridor, but up and downslope of the corridor.





                                 133

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     There are several topographic and vegetation indicators that can



indicate existing mass wasting.  Among these are U-shaped depressions,



downslope depressions, stream bank overhang, mucky surfaces, tension



cracks, curved tree butts, and "jaekstrawed" or "crazy" trees.  Some of



the indicators of potentially unstable areas are slopes greater than 70



percent, horseshoe-shaped drainage headwalls, fracture patterns, seeps



and springs, and piping (24).  These can be identified by experienced




personnel.






     Other important conditions which should be determined to evaluate



mass wasting potential of an area are in situ soil strengths, amount of



overburden to bedrock, and natural bedding planes within bedrock.  An



approximation of in situ soil strengths can be made by visual inspection



of hand-dug pits and existing soil exposures, both within the corridor



and within areas outside the corridor which are similar in nature.  The



thickness of overburden is often difficult to determine; however, an



experienced engineering geologist or similar specialist familiar with



the area and its geologic history can often provide good approximations



after  a field reconnaissance.  A geophysical survey may be  applicable in



some areas to evaluate overburden thickness but they are often  expensive



(47, 48).  It must be realized that a geophysical survey cannot be used



to evaluate the type or strength of the soils within the overburden.






     In addition to these other factors, the location  of the  water table




(which in most cases will be perched) along the alignment should be



investigated during the reconnaissance phase of investigation.  The
                                  134

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water table may be located by mapping springs and seeps in the corridor;




identifying  certain types of vegetation which exist only where water is



readily available; locating areas which exhibit some thickness of soft,



spongy, highly organic materials; or from a geophysical survey.  In



unconsolidated materials the water table may be located by relatively



shallow explorations such as hand-dug pits, hand-auger holes, or by



probing.






     After compilation and interpretation of the data obtained during



the reconnaissance, areas that present potential hazards should be



further investigated by more sophisticated means.  The major problems



involved in performing a detailed investigation of potential problem



areas is that these areas normally have only limited accessibility and,



in many cases, may require that equipment needed for such an investi-



gation be either packed in or flown in by helicopter.  Detailed in-



vestigation of these areas should be accomplished by a specialist in



soil mechanics or rock mechanics.  Such an investigation should be



specifically tailored to the field conditions at each site.






     The conditions encountered during construction may vary somewhat



from those encountered in the geologic reconnaissance due to the com-



plicated nature of deposition and formation of soils and bedrock.



Provisions should be made to alter the design during construction



according to the actual conditions encountered.






     In addition to in situ factors as discussed above, the design of



the road can have a very significant effect on mass stability.   Roads



that impose themselves on the landscape because of poor location or




                                 135

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overdesign (e.g. excessive width,  large cuts and fills to avoid occasional




steep gradients, large radii curves,  etc.) rather than conform to the




landscape are the primary cause of excessive mass stability problems on




many roads.  In order to avoid designing mass stability problems into




roads, road alignments should follow the existing topography to the extent




possible and be designed to meet the minimum standards (e.g. minimum




width, minimum length and height of cut and fill slopes, etc.) consistent




with their intended use.






CIVIL AND FOREST ENGINEERING






     The task of the civil and forest engineers on field reconnaissance




is to establish a road location that best satisfies the intended road use




within the constraints of the terrain.  The engineers are assisted and




advised by geotechnical specialists (see the previous section) and by




field surveyors.  Hopefully, experienced engineers enter the field recon-




naissance phase with some rational guidelines from their superiors about




road use and harvest method and with latitude to interpret these guidelines




in the light of actual field conditions.






Harvest Method






     Planning aspects of the road-harvest method relationship are dis-




cussed in  the planning part of this Chapter.  Adoption  of modern logging




methods  such as cable,  balloon and helicopter  appears  to be increasing




partially  due to environmental constraints  that have  the effect of  reduc-




ing  the  miles of spur and  secondary roads.   In  addition to  less roads,




the  advantage from the  sediment aspect is  that  landings for some of these






                                  136

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logging methods are preferably located near ridge tops or on high benches



as uphill yarding distances are much greater than downhill yarding dis-



tances .  Roads that connect these landings are therefore high on the



hillside away from the live stream.  Downhill yarding can concentrate



ground cover disturbance at the road or landing and may create the poten-



tial for sediment movement to roadside ditches.



     Although high lead systems are used in Alaska, downhill (e.g. Grabinski)



yarding is often employed.  Many ridge or hill tops are above the timber




line or are above the zone of merchantable timber.  Further, it is often



desirable to leave timber on the upper sections of a hillside to inhibit



avalanches.  Roads tend to be appropriately located near valley bottoms.



     The high mobility of new equipment suggests that logging operations



may be accomplished in more inclement weather than was previously con-



sidered appropriate.  However, equipment size may place constraints on



allowable horizontal road curvature and equipment weight may require



closer scrutiny of the stability of proposed landings or the road itself



if it utilizes a road turnout as a landing.






Existing Road Audit






     An audit of existing nearby roads in similar terrain and their main-



tenance and construction records may be of value to reconnaissance engi-



neers.  This audit will be useful from an overall design standpoint as



well as for potential sediment control problems.  Specific features



deserving attention are:



     1.  Surface condition of cut and fill slopes (Slope raveling).



     2.  Ditch adequacy in terms of size, shape, and effectiveness of






                                 137

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         any lining.




     3.   Culvert entrances and exits.




     4.   Performance of sediment control devices such as trash racks,




         settling basins, and downslope debris barriers.




     5.   Culvert spacing.




     6.   Geology and soils as may be revealed by exposed cut banks.




     7.   Road surface condition, i.e.  crown,  ballast performance,




         presence of surface rills.




     8.   Alignment relative to shape of terrain.




     Maintenance records of the audited road, if available,  or similar




roads may be valuable as a cross check of personal observations.  The




records  may provide a chronological order of  events and data on the




amount and kind of work accomplished for each maintenance problem.  These




records  may indicate that certain culverts were undersized,  improperly




constructed or should have had different entrance or exit treatments.




They might also indicate the extent and location of sloughing and road-




side slumping and the frequency at which roads were reshaped.  These




recordings will aid engineers in identifying  potential problem conditions




during the field reconnaissance.




     Construction inspection reports are not  always available as a part




of maintenance records.  These reports may record particular problems




during construction and indicate if they were due to the road design




or specific construction techniques.






Route Placement






     In the process of establishing a route,  the engineer may ask himself




the following questions as a guide for ensuring a thorough study of the






                                 138

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circumstances:



     1.  What are the potential risks and attendant damages?



     2.  What precautions are necessary to mitigate the risks?



     3.  What deviations in the road standard are acceptable in order



         to better accommodate corridor conditions?



     4.  What are the costs in time and money in the event of failure



         or of success?



     5.  What are the environmental results of failure?



     6.  What are the alternates in terms of road location, road



         alignment and alternate solutions to specific features?



Natural features of the corridor that should receive particular atten-



tion when there is the potential for a sediment problem include:



     1.  Proximity of live streams.



     2.  Capability of downslope areas to act as filters or buffers.




     3.  Terrain slope.



     4.  Shape of terrain in terms of degree of natural dissection.



     5.  Type of vegetative cover.



     6.  Evidence of natural soil erosion.



     7.  Presence of ground water.



     8.  Signs or indicators of natural slope stability or instability.



     9.  Circumstances at possible stream crossing points.



The civil and/or forest engineer will be assisted in the evaluation of



some of the above features by the geotechnical specialist.  However,  the



engineer, as the generalist, should make his own evaluation of the cir-



cumstances based on his knowledge of the area and his concept of the



potential effect of a road.  Road effect includes not only the effect






                                  139

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after road completion but during construction including the  practicali-



ties of construction season,  construction practices and construction




equipment.



     An important aspect in road location is the desirability of fitting



the road to the terrain.  This is stressed both in writing and orally by



experienced forest engineers.  Although it may be appropriate to enter



a reconnaissance with idealized criteria about minimum horizontal curva-



ture, maximum and minimum vertical gradients, and balancing  of earthwork



quantities, these criteria must yield to the shape of the terrain.  For



example, where short lengths of steep vertical gradients will avoid or



reduce midslope roads in the type of terrain described by Frederiksen



(2), they should be utilized.  Where a "field adjusted" horizontal curve



will avoid or reduce excavation into a potentially unstable  hillside,



it should be considered over adherence to the mathematical niceties of




a constant radius curve.



     All other factors being equal, a minimum vertical gradient of 2 to



3 percent is desirable to provide good drainage.  Flatter grades are



difficult to drain, may contribute to ponding and consequent road sur-



face deterioration under heavy truck traffic.  This in turn can cause



sediment.  Rolled grades provide convenient places to collect and remove



drainage.  Grades exceeding  10 percent may require special attention to




the potential  for ditch and  roadway surface  erosion.



     Where roads are  close to live streams,  an evaluation of the  ability



of  the vegetation, the  terrain  and the terrain  slope between the  road



and stream to  act as  a  natural  barrier to the transport  of  sediment



should be made.  Brown  believes there are limits to  the  value  of  the





                                  HO

-------
buffer strip in dissected terrain because buffer strip function assumes



that sheet flow similar to eastern agricultural soils is the major soil



erosion mechanism.  He points out that the highly dissected, rough sur-



faced topography in most forest watersheds precludes sheet flow.  Water



flows to rills or channels which converge to larger channels.  "Since



channel flow predominates, eroded materials are carried through a buffer



strip"(l).  The effectiveness of the buffer strip may vary with the tex-



ture of the soils.



     All other factors being equal, crossing a stream at right angles



to its axis affords the minimum construction in and around the channel.



The designer will rely heavily on the reconnaissance observations in



determining the appropriate stream crossing method.  The importance of



stream crossings is discussed by many writers including Frederiksen's



studies in Western Oregon watersheds (2), and Jack S. Rothacher and



Thomas B. Glazebrook's evaluation of Region 6 flood damage during the



1964-1965 floods (11).



     Features of the proposed stream crossing requiring reconnaissance



evaluation include:



     1.  Non-manufactured debris in the channel at and above the proposed



         crossing.



     2.  Stability of natural banks.



     3.  Evidence of old abandoned channels or presence of natural over



         flow channels.



     4.  Natural constrictions to high water.



     5.  "High water mark" signs.



     6.  Suitability of circumstances for ford, culvert or bridge.





                                 141

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     7.  Classification of visible soils strata.




     8.  Opportunity for flood water bypass channel over proposed




         approach roadway.




     9.  If culvert, round, pipe arch or plate arch?




Advantages and disadvantages of type of topography are discussed in the




field reconnaissance portion of the Route Reconnaissance section.



     Ground water can be converted to surface flow in mountainous areas




where a slope is cut to form a level roadbed.  Shallow coarse textured




soils overlaying relatively impermeable bedrock is a circumstance where




this phenomenon can occur.  Megahan observes that conditions are ideal




for its occurrence in the Idaho Batholith (49).  The potential for this




occurrence should be evaluated during reconnaissance so that the designer




may recognize ground water effects in his design of drainage features




and his evaluations of cut and fill stability.






Field Survey Information






     In addition to the normal route traverse and cross sectioning done by




route surveyors, there are field data to record relating specifically to




the sediment control portion of the road design.  The following is a




listing of such information:



     1.  Survey crews should be made aware of key vegetative slope




         stability and ground condition indicators (see Table 6 for




         a plant indicator key developed for use in the Siuslaw




         National Forest).  These indicators (plant colonies and tree




         dispositions) should be plotted with the traverse.




     2.  Survey crews should be alerted to take additional  cross sec-




         tions at suspect problem sites or abutting sensitive areas





                                  H2

-------
         (i.e. locations adjacent to old slide areas and streams) as



         may be designated by the engineers and geotechnical special-



         ists.



     3.  Additional information regarding cross sections at streams



         should be emphasized by the engineer.  This is particularly



         important in order to design the appropriate culvert entrance



         and exit and for determination of channel capacity.  At a



         stream crossing which will require a large culvert or bridge,



         the engineer must visit the site with the land surveyor and



         prescribe the topographic data required.



     4.  The engineer, from his field reconnaisance, may direct the



         route surveyor to take notes on natural residue and debris



         that could prove to be maintenance problems.



     5.  The surveyor should be directed to provide location data on



         unique features that influence the road in the road corridor



         and not just "on line" data.  The following items are examples.



         a.  Rock outcroppings and their condition.



         b.  Hummocky surfaces.



         c.  Terracetts.



         d.  Over steepened slopes.



         e.  Ground cracks or fissures.



         f.  Islands of over or under vigorous trees.



         g.  Natural stream scouring (continuous or intermittent streams).



         h.  Natural drainage courses.



         i.  Natural slumps and slides.



Survey notes are one of the designer's basic aids.  Recorded observations



by survey crews and accompanying sketches, if appropriate, are of great





                                143

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                                                      TABLE 6




                                   SIUSLAW NATIONAL FOREST - PLANT INDICATORS
11-9-72

Very Dry
Douglas fir x
W. hemlock '
W. red cedar
Red alder
Goats beard lichen x
Madrone c
Ocean spray x
Poison oak c
Oregon grape c
Salal R
Red huckleberry R
Rhododendron R
Vine maple
Sword fern
Oxalis
Salmonberry
Wild lily-of-the-valley
Indian lettuce
Deerfern
Bleeding heart
Devils club
Stink currant
Horse tail
Skunk cabbage
Lady fern
Maiden hair fern
Bracken fern s
Thimble berry
Trailing blackberry
Grasses s

Dry
s
x




c
R
c
x
c
c
R
R










s

s
s
Ti t** -! *-i 4-
Moist
s
X

s




R
R

X
X
X
R
R
R
R






s
s
s
s
lMrt +
wet
s
x
X
s





R

R
' X
c
X
c
c
c
R





s
s
s
s

Very We"
s
R
x
s








c
c
c
R
c
c
c
c
c
c
c
X
X


s
s


) Leaning, bowed, or pistol butt trees indicate
) recent slide activity.
) Young trees may indicate recent slide activity,
) Serai also on deeply disturbed dry area.
Indicates Site Class V

Site Class IV with yellow-green lichen.

Usually Site Class III.


) With Salal may indicate igneous rock.
) Site Class I or II when together.
)
) Dominance increased by disturbance.
) Expect intense brush competition and
) slide hazard.
)
)
)
) Only red cedar or red alder adapted to the
) extremely wet conditions (slide hazard) - also
) drainage problems.


Mature height indicates site quality, moisture
forms dense serai stands with salmonberry
) preferred elk food.

x = CLIMAX DOMINANT     s = SERAL DOMINANT




Source:  Siuslaw National Forest Engineer
                                               c = COMMON
                                                              R =  RARE

-------
value.  A portable dictating machine is of value for recording observa-




tions.




     The USFS Region 6 audit points out that "inaccurate compaction factors




and unanticipated soil changes can lead to overwidth roads and earthwork




waste" ($).  From the sediment aspect, it is desirable to handle the mini-




mum earth possible.  "Overwidth" roads may not fit the terrain as initially




conceived thereby introducing extra load on steep terrain or a stability




problem for a sliver fill.  Appropriate field survey data is mandatory to




the goals of obtaining accurate earthwork quantities, minimum changes




during construction, handling only the earth quantities necessary and




fitting the road to the terrain.






                       ECONOMIC EVALUATIONS






     The introduction to this report suggested that when sediment con-




trol design criteria was the same or parallel to other road design




criteria, a road design specifically including sediment control features




may cost no more.  No forest land manager or logger relishes the costs




of a road failure to his operation in terms of repair cost and lost




time during a harvest season.  R. B. Gardner observed that: "The invest-




ment that may be required to achieve satisfactory stability will generally



be repaid by the road's longer useful life, reduced maintenance cost,




serviceability and contributions to improved water quality and quantity"(36).










COST ANALYSIS






     The trend toward fitting the,road to the terrain with companion




change or revision of road standards to support this goal often results





                                 U5

-------
in less quantities of earthwork per station or mile than accrued with

wider roads and/or roads with higher traveling speed alignments.  Off-

setting the potential cost reduction from less quantities of material

may be the earth handling method.  A narrow road constructed full bench

with a requirement that the waste be endhauled may cost more than a

wider road constructed without full benching and with no specific waste

disposal requirement.  This latter procedure was often used.

     Wherein road elements are designed to satisfy the goal of road

stability such as stable cuts and fills and adequate stream crossings,

the cost of sediment minimization related to these elements is likely

to be included in the cost necessary to obtain a stable design.  Other

road features can be analyzed by comparing construction cost versus

maintenance cost such as ditch cleaning where tributary slopes are bare

versus ditch cleaning where tributary slopes are planted.  Elements

specifically included for sediment control such as settling basins and

downstream check dams outside of the roadway corridor are examples of

capital costs that are likely to be unrelated to road stability or main-

tenance savings.

     The Western Wood Products Associations' Forest Roads Subcommittee

has studied the minimum land impact road concept.  Appendix A to the

minutes of one of the committee's meetings listed the following as part

of criteria for minimum land impact roads.

     1.  "It should be understood that a minimum land impact road will
         not necessarily be a low-cost road, especially in  steep-sloped
         terrain with highly erodible soils.  However, provisions for
         minimum roadway and clearing width in difficult terrain situa-
         tions will mean less cost for initial road construction and
         subsequent maintenance, site restoration, and revegetation fo"
         soil erosion control."


                                 146

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          2.  "The total cost of construction, operation, and maintenance of
              a road should be carefully assessed at various design standards
              to find the optimum output for the three principal cost centers.
              The various levels of road design standards should be compared
              to the degree of impact each design standard places on the re-
              sources and immediate environment.  A possible output mix of
              costs and impacts could be developed for comparison between
              alternatives" (50).

          Gardner offers some guidance on road standards, economics and environ-

     ment in terms of amortized construction cost over road life, maintenance

     and operating cost, the cost centers suggested by WWPA.  Tables 7 and

     B demonstrate the value of an investment in roadway ballast as the annual

     cost of gravel roads is less than stabilized and primitive roads.  On the

     basis that ballasted roads have less potential for sediment production

     than primitive roads, the ballast investment pays in terms of sediment

     minimization as well as minimum annual cost.


                                    TABLE 7

                      COMPARISON OF ANNUAL ROAD COSTS PER MlLEj
                      10,000 VEHICLES PER ANNUM (VPA)


             •
             *
Cost         ;                            Road standard     	
distribution :2-lane :2-lane:  2-lane:  1-lane :1-lanei1-lane
	;paved  ; chip-seal :  gravel  ;  gravel ;spot stabilization;  primitive
              ------------Dollar per mile --------------

Initial
construction  50,000    -40,000     30,000    20,000      15,000           10,000
------- Annual dollars
— Depreciation
Maintenance
Vehicle use
4,360
200
2,200
3,490
400
2,300
2,610
600
2,700
per mile (20-year period)
1,740
800
3,000
1,310
1,100
4,400


870
500
8,500
                                            2/
Total annual   6,760     6,190      5,910   -5,540       6,810            9,870
__

   _,20 years at 6% using capital recovery.
   — Lowest annual cost.

                                      147

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                                    TABLE 8

                      COMPARISON OF ANNUAL ROAD COSTS PER MILE FOR
                      20,000 AND 40,000 VEHICLES PER ANNUM  (VPA)
Cos't         ;
distribution :  2-lane :2-lane
                     	Road standard
                      2-lane :  1-lane :
             :  paved
                                   1-lanei1-lane
chip-seal:   gravel :  gravel :spot stabilization:  primitive
                                        Dollars  per mile
Initial
construction
50,000   40,000
           30,000    20,000
15,000
10,000

-"- Depreciation
Maintenance
Vehicle use
Total annual
Depreciation
Maintenance
Vehicle use
Total annual -'•
4,360
400
4,400
9,160
4,360
800
8,800
13,960
3,490
800
4,600
i/8,890
3,490
1,600
9,200
14,290
2,610 1,740
1,200 1,600
5,400 6,000
9,210
- ( Z.O
2,610
2,400
10,800
15,810
9,340
non VPA ^
1,740
3,200
12,000
16,940
1,310
2,200
8,800
12,310
1,310
4,400
17,600
23,310
870
1,000
17,000
18,870
870
2,000
34,000
36,870
   —.20 years'  depreciation at 6% using capital  recovery.
   — Lowest annual cost.
          On the basis that the minimum road has  less  environmental  impact,

     Gardner suggests that the user cost for the  environment  is  represented

     in Table 9 by the difference in annual  cost  between  two  lane  paved  and

     one lane gravel roads (51).  Ignoring environmental  considerations,  the

     lower annual cost road is a two lane paved one  when  traffic is  20,000

     vehicles per year or more.  With environmental  factors requiring  a  one

     lane gravel road, the annual cost is greater for  more than  20,000 vehicles

     per year.
                                      148

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                                    TABLE 9

                COMPARISON OF SINGLE-LANEi VERSUS DOUBLE-LANE COSTS FOR
                THREE DIFFERENT VEHICLE-J>ER-ANfflJM (VPA) CATEGORIES
*
VPA :
:


10,000
20,000
40,000
Total annual

1-lane
gravel

5,5-40
9,340
16,940
cost per mile :
• •
: 2 -lane :
: paved :

6,760
9,160
13,960

Difference



-1,220
+ 180
+2,880
Source:   Gardner, R. B., "Forest Road Standards As Related to Economics and
          the Environment," USDA Forest Service Research
          Note INT-45, August 1971, 4 pages


          The cost figures shown in the table are not applicable to all of

     Region X.  Gardner's work was published in 1971.  However, he does suggest

     a cost analysis approach that includes environmental considerations.

          For readers interested in vehicle operating costs on logging roads,

     R. J. Tangeman has proposed a model for estimating these costs relative

     to characteristics of forest roads (52).

          The Environmental Protection Agency's publication Comparative

     Costs of Erosion and Sediment Control, Construction Activities includes

     a procedure for determining the annual economic cost of conserving soil.

     The procedure recognizes amortized cost of the capital investment and

     annual maintenance costs.  The report cautions that "each particular

     location offers a unique soil loss potential, erosion control costs and

     corresponding sediment removal penalties" (53).
                                      149

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ECONOMIC JUSTIFICATION






     An economic justification for additional capital investment in road




elements to achieve greater road stability under adverse conditions is




the risk of potential cost of a road failure.  To illustrate this,  cul-




verts and bridges should be designed to survive an anticipated storm




event.  This means that hydrology studies and site surveys at bridge and




culvert crossings are necessary.  Hydrology studies and detailed site




surveys cost money and the results of these studies may produce large




capital expenditures.  Even so, this type of investigation is essential




if washed out bridges and culverts are to be prevented.




     The 196/4-65 winter season floods in Oregon have been classified as




50 year floods in higher elevations.  "The transportation system suffered




by far the greatest monetary loss.  Damage to roads, bridges and trails




in Oregon alone was estimated at $12,500,000 - 4 percent of the total




investment of $355 million" (ll).  This estimate does not include down




time cost or other inconveniences which accompanied these losses.  The




flood damage estimates to USFS Region 6 roads and bridges for the 1973-74




season is in excess of the 1964-65 damage estimate.




     Sediment control can also act as preventative maintenance.  Seeding




slopes for erosion control can prevent slope raveling.  Slope raveling




can diminish the roadway prism and cause high ditch and culvert main-




tenance costs.




     Economic justification should be related to the role the intended




road is to play in the overall land management goal.  The broader the




goal, the more varied are the inputs to the economic analysis.  Legal






                                 150

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requirements such as water quality criteria are "givens" to the engineer



as a part of the land management goal.  Within these "givens", the engi-



neer must exercise his traditional role of preparing cost effective,



economic designs.
                                 151

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                           DESIGN
     "Road design is the process  of  transplanting planning objectives,
     field location survey data,  materials investigations and other
     information into specific  plans,  drawings and specifications to
     guide construction" (5).

The designer's task is to translate  this  data into a design which recog-

nizes and provides for sediment control.

     When initiating a design,  a  designer must grasp an understanding of

the field work, reconnaissance  and planning that has preceded  him.  He

must also understand management objectives and policy.  This information

may be provided in a number of  ways  depending upon the organization's

structure.  In some organizations, the designer has been a part of the

reconnaissance, and will be the construction supervisor.  In others he

may have only limited personal  contact with reconnaissance people.

Regardless of the organizational  size  and procedures or the designer's

disposition, there are several  general features which the designer should

know in order to intelligently  proceed.   The following list is not all

inclusive.

     1.  The designer must be aware  of the road's intended use, such as,

         whether it will be principally a truck haul road, log landing

         or yarding platform, or  will  have other demands.  Prior know-

         ledge of this kind may affect such choices as water bars or

         pavement, fords or bridges, and  grades and curvature.

     2.  A review of the reconnaissance and field information should

         indicate to the designer the  conditions within the reconnais-

         sance corridor.  If  this review  arouses doubt or lack of under-

         standing, he must communicate with those who accomplished the


                                 153

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         field work.  Preferably, the designer should at least visit

         the site of specific key features within the project such as

         stream crossings and steep hillsides.

     3.  The designer should have authority to obtain additional field

         information and to alter design standards in order that a stable

         road will be attained.

     4.  The designer should know to what extent he will be able to

         follow the job through, and what control he or others will

         exercise on workmanship.  Quality construction is imperative

         to the control of sediment.

     The designer must familiarize himself with erosion control and road-

way stabilizing techniques.  He must also be committed to sediment con-

trol and to the exercise of a degree of creative thinking.

     This chapter is divided into four parts.   The first part discusses

matters of the roadway design itself, the second part is devoted to fea-

tures of slope stabilization including a discussion of seeding and plant-

ing, mulches and mechanical treatments.  Since many of the recorded mass

failures on forest roads appear to be drainage related, the third part is

devoted entirely to drainage design including ditches, culverts and stream

crossings.  The last (fourth) part discusses features of the construction

specifications, prepared as part of the design task, that support the

goal of minimizing sediment.


                              ROADWAY
             >
     Many features or concepts for the roadway design may have been

developed or established as a part of the reconnaissance.  However, the

                                 154

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process of converting field reports, field survey notes and planning




goals to drawings with attendant horizontal and vertical control will




help resolve key details and controls that will appropriately refine




and execute the reconnaissance and planning information.  This part dis-




cusses sediment features of the following roadway design elements: align-




ment, roadway prism, roadway surfacing, buffer and filter strips.






HORIZONTAL AND VERTICAL ALIGNMENT






     Horizontal and vertical alignment are design features that can be




used to develop a road sensitive to sediment control.  In developing




such a road, these features must be manipulated by the designer to




adjust the road alignment as the constraints of the terrain demand.




The discussion on reconnaissance in the previous chapter emphasized the




importance of fitting the road to the terrain.




     The designer must also recognize the limits that may be placed on




him by the reconnaissance data and location.   With the aid of field sur-




veys, geotechnical, civil and forest engineering information, he can




adjust the horizontal and vertical alignment to the terrain with compan-




ion attention to road use requirements.




     The potential for generating roadway sediment can be mitigated by




utilizing a horizontal alignment that reduces roadway cuts and fills,




and avoids or minimizes intrusion upon unstable ground.  If necessary,




the designer must have flexibility to adjust curve radii from that




established by arbitrary road standards.  The designer's practical




experience and judgement are a part of his approach.   The sediment con-




trol aspect has to be weighed with other features.






                                 155

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     Vertical alignment, like horizontal alignment,  can be used to help




control sediment.  In unstable steep terrain, adjusting the vertical




alignment to reduce cuts and fills and to position the road on stable




benches is an intelligent approach.  In level areas sediment control is




aided by providing appropriate drainage to the roadway and roadway ditch.




A minimum grade of 2 percent will prevent ponding and reduce subgrade




saturation.




     Roads from log landings provide another opportunity to practice




sediment control and preventive maintenance.  A 5 percent adverse grade




from landing to road for approximately one hundred feet will reduce the




potential for mud and debris movement to the haul road.




     Use of steep pitches to reach stable terrain must be accompanied by




appropriate treatment of the road surface; otherwise, the road surface




can be subject to serious rill erosion.  This matter is discussed further




under Road Surfacing.






ROAD PRISM






     The roadway prism is defined as the geometric shape generated by a




through fill, through cut, partial bench or full bench.  The third part




of this chapter discusses the roadway ditch portion of the prism, the




next part discusses slope stabilization and the road surface paragraph




of this part, roadway surfacing.  The following discussion is limited




to excavation, embankment and balanced construction.






Excavation






     Back slopes can contribute up to 30 percent of the total road




sedimentation and up to 85 percent of the first year road sedimenta-





                                 156

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tion (43,4).  Sediment can be reduced by slope stabilization tech-



niques as considered in the next part and/or by designing the back



slope for the given soil characteristics.  The Route Planning and



Reconnaissance  chapter discusses geotechnical and engineering recon-



naissance techniques to develop field data for the design of stable



back slopes.  There are two approaches to back slope design, one is



experience, and the other is rational  or technical procedure.



     Use of "rules of thumb" or "standard" backslope steepness guides



without knowledge of specific soils conditions is dangerous.  However,



if an able forest engineer with long experience in a particular area



has been successful in establishing stable backslopes for road cuts,



his approach, advice and experience should be utilized.



     The route planning discussion in the previous chapter noted that



the U.S. Forest Service has adopted a method of specifying cut and



embankment slopes developed by Hendrickson and Lund (21).  This concise,



rational method does not require extensive laboratory equipment to ob-



tain soil type, grain size, and distribution for the unified soil classi-



fication.  It also considers blow count, ground water,  site conditions



and slope height.  This design method is presented in both graphical



and tabular form for convenient use along with illustrative examples.



Also,  and perhaps equally important,  are the application and limitation



discussions that accompany the design guide (22).



     Rodney W. Prellwitz has developed a slope design procedure for low



standard roads in USDA Forest Service Northern Region (Montana, Northern



Idaho and Eastern Washington).  Prellwitz's procedures  are most applicable



to Northern Region conditions of (l)  steep natural slopes and cut slopes,






                                 157

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 (2)  seepage  - often parallel to surface slope, (3) "non-cohesive" soils,




 (4)  shallow  and erratic soil depth, and (5) seasonal ground water fluc-




 tuations  (5-4).




     Vertical cuts in banks less than six feet are being tried in




 various parts of Region X including Idaho and Alaska.  The rationale




 behind the vertical cut concept is that these cuts will reduce excava-




 tion quantities and the area of exposed new backslope.  However, it is




 difficult to predict the reliability of this practice from a sediment




 control standpoint or how universally this practice can be applied.






 Embankment






     Numerous researchers suggest that fill slopes are significant ini-




 tial producers of road sediment.  They also point out that fill slope




 erosion can be drastically reduced by erosion control techniques.




     Mass failure of the fill is the other source of sediment.  Mass




 failures can be the result of poor fill material, improper fill compac-




 tion, incorrectly designed fill slope, improper foundation preparation,




weak foundation support, improper culvert design and installation with-




 in the fill,  or a combination of one or more of these conditions.  The




 design of a fill is a structural problem with the companion necessity




 to recognize the site circumstances.  The procedure developed by Hendrick-




 son and Lund, mentioned in the discussion on excavation,  can also be




 applied to embankment design.




     Examination of the underlying strata where a fill is proposed must




be accomplished during the reconnaissance.  If the strata is too weak




for the proposed load, the road must be relocated, the fill height re-






                                 158

-------
duced or an alternate structural solution such as a trestle considered.




     A common fault has been lack of proper ground preparation by




clearing and stripping vegetation and organic material.  A further




problem has been the presence of too much organic matter in fill mater-




ial.  The next chapter discusses fill placement techniques.




     Benching of fills into sloping terrain has been utilized success-




fully.  On narrow roads in steep terrain, the bench may be equal to the




road width.  This suggests that there is a point where terrain slope




and road width combine to require a full bench section rather than a




fill from a practical as well as a stability viewpoint.




     A stable fill slope is dependent upon the quality of the fill




material and the required area of supporting ground that must be util-




ized to support the superimposed load.  The chapter on Construction




Techniques discusses fill compaction.




     Provision for the passage of uphill overland water through a fill




can often be made by placing a granular blanket on the ground as the




first fill layer.  Otherwise,  the fill may act as a dam to the water




with dangerous damage potential.  This blanket also aids in equipment




operation when the ground is soft.




     The foregoing are a few observations on fill stability.  The stabi-




lity question is broader in scope than the matter of sediment minimiza-




tion only.  Waste sites are also fills and must be designed accordingly.




Culvert design is discussed in the third part of this chapter.
                                  159

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Balanced Construction






     No simple statement can be made as to whether or not the concept of




balancing the quantities of excavation and fill materials has merit from




the viewpoint of sediment minimization.  If the excavation can be con-




fined to the amount of earth needed for fill and other factors are equal,



this is advantageous.




     On steep terrain full bench excavation to obtain stability often




results in the production of excess material.  "Sliver" fills on steep




terrain have proven difficult to stabilize.  In order to reduce excava-




tion, an alternate to the "sliver" fill might be a driven sheet of soldier




pile and lagging wall.  The economic tradeoffs would be excess excavation




costs plus haul of excess material and waste site development versus the



wall cost.






ROAD SURFACING






     There is a broad range of surfaces and surface treatments used on




logging roads.  Selection of surfacing or surface treatment may depend




upon material availability, road use,  road location and construction




practices.  In southeastern Alaska, nearly all roads are constructed




with "shot rock" ballast and overlaid with gravel or crushed rock.  In




some areas of Oregon, Washington and Idaho, the absence of quality sur-




facing rock may result in soil surface roads of bituminous surfacing.




     There is no doubt that durable surface roads result in less potential




for surface erosion.   However, surfacing a road does not necessarily elim-




inate sediment problems.  In many parts of the region the logging season




carries into wet weather periods and,  in lower elevations, logging may






                                 160

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continue year around with only occasional winter shut-downs.  Log haul-




ing operations during this period place additional demands on roads.  It




is the designer's task to anticipate this use if appropriate and to de-




sign a base and surface for the particular subgrade and wheel loads.




(The design must be coupled with good construction practice).




     The road surfacing does more than provide smooth travel and a load




distributing media.  It also provides a "roof" for the subgrade by being




a dense roadway surface, crowned sufficiently to rapidly disperse water.




Non-bituminous log haul roads should be crowned 4 percent minimum




to insure the movement of surface water.  This reduces potential sub-




grade saturation.




     In addition to designing a road base and surfacing to support




truck traffic and road crown selection, the following are other design




considerations that may directly or indirectly affect the potential




for roadway erosion and sediment.




     1.  Pit-run gravel surfacing must have an aggregate gradation




         which will compact to a dense water dispersing surface.




     2.  Crushed rock surfaces rely on their angular faces and grada-




         tion of the aggregate to knit the surface into a dense, near-



         impervious layer.




     3.  Asphaltic concrete or other pavements decrease the time for




         rain water to concentrate in ditches and other drainage




         structures.




     4.  Granular-surfaced roads can become sediment producers if a




         soft crushed rock is used or if the gradation does not permit




         a dense, locked,  shear resistant surface.






                                 161

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     5.  Water bars—spaced,transverse surface depressions are often




         used as cross drains on steep longitudinal grades.   However,




         they require continual maintenance if they are placed on too




         flat a grade.  A minimum longitudinal roadway grade of 5 per-




         cent is suggested for use of water bars.




     6.  If steep grades in excess of 10 percent are used, asphaltic




         concrete or bituminous surfacing may be required in lieu of




         water bars to maintain a stable road surface.




     7.  Asphaltic concrete or bituminous surface can be used as




         approach aprons to bridges.   They reduce material tracking




         which wears bridge decks, and washes sediment into streams.




     8.  Gravel surfaces may have an economic trade-off when the




         annual traffic operating costs and maintenance costs off-




         set those of soil stabilized or primitive roads (51).




     9.  Choice of gravel surfacing on outslope roads, versus stabi-




         lized or soil surface is related to the potential for rill




         erosion.  See the discussion in the drainage section.






BUFFER STRIPS






     The concept of minimizing or retarding downslope sediment movement




with vegetation and/or obstructions has been studied and used for a num-




ber of years.  The procedure is often coupled with the outslope road




with surface cross drains.  Drainage features of the outslope road in-




cluding criteria for cross drain spacing are discussed in the third part




of this chapter.  Reservations regarding the ability of vegetation and




terrain to act as a barrier to sediment movement as expressed by one




writer are mentioned in the discussion on route reconnaissance.





                                  162

-------
     Most of the data developed is based on studies in Idaho, Eastern

Washington and Montana where the outslope road is quite common.  Harold

F. Haupt studied sediment movement in the Boise National Forest in 1959.

He developed an equation relating sediment flow distance to a slope

obstruction index, cross ditch interval, embankment slope length and

cross ditch interval times road gradient.  The Slope Obstruction Index

was approximately equal to the average spacing in feet of major obstruc-

tions along the direction of slope.

     "With proper substitution of the variables, this equation pre-
     determines the distance or width of protective strip needed to
     dissipate sediment movement that may occur from a road to be
     built" (55).

Haupt pointed out that the method was a tool for designers and was not

a substitute for experience and good judgement.

     Packer believes that the interaction between the spacing of down-

slope obstructions and the kind of obstruction, and the spacing between

obstructions are the two most important factors in evaluating sediment

movement.  Figure 20, "Obstruction Spacing", is reprinted from Packer's

1967 Study (56).  Packer also discovered that, as the age of the road

increased, the distance sediment moved downslope also increased.  This

was because the capacity of obstructions to stop sediment decreased the

longer they were installed.

     Packer also developed criteria for protective strip widths based

on obstruction spacing, kinds of obstructions, age of road and cross

spacing.  Table 10 is reproduced from Packer's report.   The table is

also contained in the booklet Guides for Controlling Sediment from

Secondary Logging Roads by Packer and George F. Christensen (4-6).  This
                                 163

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field manual is pocket size and contains a complete treatment of the



subjects of cross drain spacing,  and protective strip widths.  It also



tells how to apply the information in a manner that will control erosion



and sediment.  The booklet is geared for use in USDA Forest Service




Northern Region.
                                  164

-------
H
03
5 80
«60
O
S 40
 •
H
fe

S 8<>
^^
Q
H
QQ
                                             X
              X/^r/
     /e»    ^U^
V^'V*
*y/' ^«0c&
            8468
            OBSTRUCTION   SPACING
                         FIGURE 20

      Distances of sediment movement down-slope froa the
      shoulders of logging roads built on soil derived from
      basalt, having 30-foot cross-drain spacing, 100-percent
      fill slope oover density, and zero initial obstruction
      distance under varying obstruction spacings and kinds
      of obstructions.
                          165

-------
                              TABLE 10
Protective-strip widths required below the shoulders(l) of 5-year old(2)
logging roads built on soil derived from basalt,(3) having 30-foot cross-
drain spacing,(4} zero initial obstruction distance,(5) and 100 percent
fill slope cover density( 6).
                       Protective-strip widths
Obstruction  Depressions  Logs  Rocks   Trees and  Slash and  Herbaceous
 spacing      or mounds                  stumps      brush    vegetation
1
2
3
4
5
6
7
8
9
10
11
12
35
37
39
40
41







37
40
43
46
48
50
52
53
54



38
43
47
52
56
59
62
65
67



40
46
52
58
63
68
73
77
81
85
88

41
49
57
64
71
77
84
89
95
100
104

43
52
61
70
78
86
94
101
108
115
121
127
(l) For protective-strip widths from centerlines of proposed roads,  in-
crease above widths by one-half the proposed road width.
(2) If storage capacity of obstructions is to be renewed  when roads  are
3 years old, reduce protective-strip widths 24 feet.
(3) If soil is derived from andesite, increase protective-strip widths
1 foot; if from glacial silt,  increase 3 feet; if from hard sediments,
increase 8 feet; if from granite,  increase 9 feet;  and if from loess,  in-
crease 24 feet.
(4) For each 10-foot increase  in cross-drain spacing beyond 30 feet,  in-
crease protective-strip widths 1 foot.
(5) For each 5-foot increase in initial obstruction distance beyond  zero
(or the road shoulder), increase protective-strip widths  4 feet.
(6) For each 10-percent decrease in fill slope cover below a density of
100 percent, increase protective-strip widths 1 foot.
Source:  Packer, Paul E.,  "Criteria for Designing and Locating Logging
         Roads to Control Sediment",  Reprint from Forest Science^
         Volume 13,  Number 1,  March,  1967.
                                 166

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                          SLOPE STABILIZATION




     Stream sedimentation can result from surface erosion or mass




wasting.  Some of the measures which may be utilized to reduce surface




erosion and mass failures are discussed in the following sections.






SURFACE EROSION




     The construction of forest roads is the major cause of stream




sedimentation in the forest harvest system.  Large quantities of




sediment are produced from roads as a result of surface erosion and




mass wasting.




     Revegetation of areas disturbed by logging road construction




is the most effective means of reducing sediment production.  Mulches,




chemical soil stabilizers, and mechanical treatment measures are




often required initially to help establish vegetation and to reduce




erosion during this critical period.  The various types of slope




stabilization procedures and their effectiveness in reducing sedimentation




are discussed in the following sections.






Seeding and Planting




     IntToduoti-on.   Numerous studies indicate that forest cover is




among the most effective vegetation in maintaining and protecting




soil from erosion (43).   This cover reduces the effects of raindrop




impact;  decreases runoff velocity and erosive power;  increases granulation,




soil porosity, and biological processes associated with vegetative




growth;  and dries soil by evapotranspiration.




     Logging road construction removes natural vegetation and exposes




soils which commonly have properties unfavorable for plant growth (57).






                                   167

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Revegetation by seeding and transplanting can be a successful method

of stabilizing backslopes and fills, of "putting roads to bed" that

are no longer being used, and of filtering sediment-laden water flowing

into water courses (58).

     The decisions as to which plant species and methods to use in

EPA, Region X, for roadside stabilization are currently made by a

variety of agencies and individuals, usually the Soil Conservation

Service, individual county extension agents, landscape architects,

and the Forest Service.  These decisions depend upon the management

objectives, financial problems, and the unique soil and climatic

features of each site.  Although there are published standard specifications

for erosion control using revegetation techniques, the actual methods

used by the Forest Service vary from forest to forest and even among

districts of a given forest (59).

     Revegetation Objectives.   The main objective of seeding roadsides

is stabilization of soils against surface erosion.  Recolonization

by native shrubs and herbs is generally encouraged (60).  Native

plants generally require less expense and maintenance as well as

being visually harmonious with the forest landscape although many

exotic species are also well suited for this purpose.  In addition

to physically enhancing the soil, seeded grasses and legumes— improve

the organic-mineral balance of road-cut soils.  They also act as

"nurse plants" to young native species by providing shade thereby

reducing evaporation from the soil.
I legume :  any of a large group of plants of the pea family.  Because
  of their ability to store and fix nitrates, legumes are often plowed
  under to fertilize the soil.
                                168

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     Grass seeding is usually considered as an erosion prevention



treatment applied at a sacrifice to tree regeneration, although tree



regeneration is not always sacrificed.  In southeast Alaska, grass



seeding of exposed mineral soils helps establish spruce and hemlock



seedlings by reducing the disruptive influence of frost heave and



by retarding alder invasion (6l).



     Shrubs are sometimes planted on wet silty and clayey soils where




the slope is not steep.  Native willows (Salix spp.) and alders (Alnus



spp.) are used in EPA, Region X, because they absorb large amounts



of water from the soil and, in effect, dry it out.  They are also



more deeply rooted than grasses or legumes.



     Seed Mixtures.   The proper seed mixture for a particular site



is dependent upon many factors.  Among these are (l) slope stability,



angle, aspect, and exposure; (2) general climatic conditions, including




conditions at the time of planting; (3) competitive ability of species



to be planted in relation to native weed species or desired ultimate



vegetation establishment; (<4) susceptibility to foraging by livestock



and big game species; (5) visual and aesthetic considerations; and



(6) physical and chemical characteristics of the soil.  Soil conditions



are particularly important because much of the material is often



C-horizon soils at best and not well suited for growing vegetation.



     Because of wide variations between sites and the adaptability



of individual grass and forb species, no specific grass mixtures



are recommended in this report.  Unless related to individual site



conditions, specific mixture recommendations are of little value.



Appropriate specialists should be consulted in each case to tailor





                                 169

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the seed mixture to site conditions.  These specialists include soil




scientists, agronomists, ecologists, range conservationists, and




wildlife biologists within the Forest Service and Soil Conservation




Service; universities; extension agents; landscape architects; and




consulting "biologists.




     Rarely are grasses seeded without legumes, and the choice of




legumes is an important decision (62).  The inclusion of a vigorous




fast-spreading legume in the seeding mixture in some cases results




in a denser and longer lasting stand of herbaceous vegetation, presumably




because of the nitrogen incorporated into the soil (59).  Seeding




a legume requires that one also applies an inoculant of the associated




root bacteria.  The inoculant is usually "glued" to the legume seeds




before the seed mixture is made (63).




     Several legumes including big trefoil, white Dutch clover and




New Zealand white clover, birdsfoot trefoil, and alfalfa have been




found suited for use in the Northwest (59).



     However, one problem of including most legumes in a seeding




mixture is their high palatability to deer, elk, and livestock.




Alfalfa is particularly palatable.  Grazing animals will trample




out mechanical structures, pack the soil, and create a more erosive




condition than existed prior to seeding (10).  Legumes should not




be included in seed mixtures on sites readily accessible to big game




animals, cattle or sheep.  The Forest Service Experiment Stations




are continuing to search for vigorous, unpalatable legumes to use




in seeding mixtures (59, 62, 64).



                                 170

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     Plant-Ing.  Planting in logging road stabilization is for utility,




not aesthetics.  Where soils are plastic (e.g., silty and clayey),




growth of native willows or alders should be encouraged because they




inhibit slumping by depleting soil moisture rapidly, and their roots




bind soil to a deeper level than do those of grasses and legumes.




Red alder (Alnus rubra) is the species used in Washington and Oregon,




and Sitka alder (Alnus sitchensis) is used in southeast Alaska.




There are many species of willow common to EPA, Region X, and nearly




all root readily from cuttings, as do the alders.




     Recent research in Idaho indicates that many native forbs have




outstanding qualities for roadway planting.  The most promising species




is Louisiana Sagebrush (Artemisia ludoviciana).




     Plantings are much more expensive than seeding operations because




of the increased cost of plant materials and labor.  Hand planting




of grasses and legumes in small, hard to reach sites which require




revegetation is done in some parts of Oregon and Washington (60).




This procedure is not yet used in Idaho or Alaska (6-4,  65),  primarily




because of the expense.




     Techniques Used -In Establishing Plants.   Seeding,  as mentioned



previously,  is much less expensive and, therefore, much more widely




used than other planting methods.   Commonly used methods of seed




application are hydroseeding,  hand-operated cyclone seeders, and




truck-mounted broadcast seeders.  Hydroseeding is the application




of a seed and water slurry to the  soil, in some cases followed by




an application of fertilizer and mulch (63).   If seed and mulch are




applied simultaneously,  much of the seed may stick to the mulch and




                                171

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never contact the ground.  A variety of mulches—wood cellulose fiber,
ground hay, ground newspaper—have been applied by this method.
     Hydroseeding is used in all parts of EPA, Region X, by highway
departments.  In Oregon and Washington, the Forest Service hydroseeds
(60).  The use of cyclone seeders and seed blowers is quite common
for areas which cannot be hydroseeded because of the expense involved.
The Forest Service in Alaska usually uses a cyclone seeder (64).
In Idaho, seeding is typically accomplished by using a cyclone seeder.
If the seedbed is packed, it may be necessary to drill the seed (10).
Drill seeding is superior where it is possible, but it is limited
to only the flatter slopes.
     Hand planting is generally restricted to critical areas with
high priority because of the high cost.  Hand planting of grass or legume
plants in Washington and Oregon is done in difficult to reach places
(60).
     Proper seedbed preparation is very important.  The soil surface,
if not freshly prepared, should be roughened along the contours in
order to reduce the chance of rilling and to provide small depressions
which retain the seed.
     When to Seed ov Plant.  From the standpoint of minimizing sediment
production, roadside revegetation should be started as soon as roads
are constructed if conditions are favorable.  The highest volume
rate of soil movement off road cut and fill slopes is in the one to two
months   immediately following road construction (66, 67).  If this
period does not coincide with the season which favors the species
being planted, mulches or other temporary stabilization measures
should be used in the interim period.
                                 172

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      Generally,  seeding during  the  spring  or  fall  is best.  Summer



 seeding  should generally be avoided because of  limited moisture  avail-



 ability.   In western Washington and Oregon, seeding before  the fall



 rains is  recommended.   One  source reported success with  seeding  in



 September,  another  in April (66, 67).   In  Idaho, seeding should  be done



 in late  summer or early fall in order  to take advantage  of  the fall rains



 (10).  In Alaska, seed  should be applied in April  or early May,  but




 summer application  before August 1  is  acceptable where spring application



 is not possible  (68).   For  quick temporary cover in Alaska  after the



 recommended planting season,  annual ryegrass  can be seeded  immediately,



 followed  by seeding perennial grasses  the  next  spring or summer  (69).



      The  advantage  to seeding and planting prior to fall rains is that



 the newly introduced plants  are not subjected to undue moisture  stress



 as in summer.  This is  especially true in  dry areas such as eastern



 Washington and Oregon and southern  Idaho.




     Ferti-l-izers.   In all cases, application  of fertilizer  enhances



 revegetation.  Fertilizer should be applied at the time  of  seeding and



 again  the  following spring.   Subsequent fertilizations at one or two-year



 intervals may  be required in  some instances,   particularly where  soils are



 composed largely of B-  and C-horizon materials which are normally very



 low in nutrients.   The  fertilizer type and quantity, as with seeding



mixtures,  should be  tailored  to the individual conditions encountered at



 each site.  Usually, a nitrogen-phosphorus-potassium fertilizer is suffi-



 cient; although if  the  soil pH is less than 5, an application of lime may



be required (69).   In general, ammonium phosphate (15#N,  20%P and 0$IC),



ammonium sulfate (21$N,  0%P, 0%K and 24$S) is excellent.   Soil sampling




                                  173

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and testing will reveal any serious nutrient deficiencies,  and ferti-



lizer types and application rates can be tailored to satisfy these




deficiencies.



     Because native shrub and grass establishment is the primary goal



of roadside grass plantings on Forest Service roads in Washington



and Oregon, only one to two fertilizer treatments are applied.  Continued




fertilizer treatments result in such a vigorous growth of the seeded



species that the natives cannot establish on the seeded area (60).



     Mulching.   Mulching is essential if a good seedbed cannot be



prepared, if soil is highly erodible, or if slopes are steep (70).  If



seed cannot be applied immediately after construction, the application



of a mulch alone will greatly reduce soil movement down the slope.



Mulches not only decrease soil loss by buffering rain effects and



slowing runoff, but they also retain soil moisture and provide shade



for better seed germination and seedling establishment.  Mulches are




discussed in more detail in a subsequent section.



     Summary.   In spite of the variety of revegetation methods used



in EPA, Region X, and the uniqueness of each roadside stabilization



project, some generalizations about the usefulness of plants for



erosion control can be made.  The combination of vegetation and structural



methods recommended depend on the objectives of the action.  The seed



mixtures used in Region X should be tailored to the conditions existing




at each site.  Although quite expensive, planting of willow and alder



is an effective way of drying out wet, heavy soils.  Hydroseeding and




cyclone seeding are the most common methods of seed mixture application



used.  Hand planting is expensive but necessary in hard to reach



spots.   Application of slope stabilization measures should be



                                   174

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commenced immediately after construction.  The best season to seed




is generally fall or spring.  Applying fertilizer and a mulch consistently




improves seed germination and growth and minimizes erosion which




can take place before the seedlings are established.






Mulches and Chemical Soil Stabilizers




     Introduction.  Measures intended for overall surface soil stabiliza-




tion of broad areas, exclusive of vegetation, can generally be classified




as mulches or chemical soil stabilizers, although some variations




of each exist.  A mulch can be described as any organic or inorganic




material applied to the soil surface to protect the seed, maintain




more uniform soil temperatures, reduce evaporation, enrich the soil,




or reduce erosion by absorbing raindrop impact and intercepting surface




runoff (58, 71).  Chemical soil stabilizers can be described as any




organic or inorganic material applied in an aqueous solution that




will penetrate the soil surface and reduce erosion by physically




binding the soil particles together.  Some chemical stabilizers also




reduce evaporation, enrich the soil, and protect the seed (58, 71).




In addition to their functions in protecting against water erosion,



these measures also protect denuded soil, seeds, and young plants




from wind erosion.




     Mulches and chemical stabilizers are generally temporary measures




which can be expected to lose their effectiveness within one to two




years or less.  Their primary purpose is generally to provide suitable




short-term protection, including erosion reduction, during establishment




of permanent vegetative cover, usually over winter months or through





                                 175

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hot summer months until conditions are more favorable for vegetative



stabilization (58).  However, some mulches can be used to provide



permanent slope protection in areas where adequate vegetative cover



cannot be established.



     Some of the more commonly available mulches are hay or straw,



woodchips, and small stones or gravel.  For some types of mulch,



particularly hay or straw, it is necessary to provide some means



of holding the material in place.  Methods of attachment include



mechanical means (e.g., notch-bladed disks, crawler tractor with




deep treads, sheepsfoot rollers, and others), asphalt or chemical



binders, or various commercially available netting products (58).



In order for mechanical attachment to be effective, the surface of



the slope must be free of significant quantities of rock material.



     Besides their use for mulch stabilization, many of the chemical



stabilizers and netting products are designed to themselves protect



slopes under appropriate circumstances.  Also, several commercially



available products incorporate netting and mulch in a single cover.



These products (e.g., Excelsior Blanket, Conwed Turf Establishment



Blanket, etc. ) are more specifically applicable on steep slopes,  in



small drainage swales, or in other areas where erosive stresses are



particularly high (58).  Long wire staples are generally used to fasten




these and other netting-type products to the slope.



     Numerous studies have been conducted to evaluate the need for



mulches and chemical stabilizers to establish vegetation and control



erosion.  Most of these studies have as their primary purpose evaluated



the relative effectiveness of different types of mulches and chemical




                                 176

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soil stabilizers in performing these functions.  In the following
sections, the need for slope protection to aid vegetation establishment

and control erosion and the relative effectiveness of various types
of mulches, mulch rates, and chemical stabilizers will be discussed.
     Need for Slope Protection During Vegetation Establishment.
Mulches serve two primary purposes during vegetation establishment:
(l) preventing erosion while vegetation is becoming established,
and (2) providing a suitable microclimate for vegetation establishment.
Both functions are important.  If severe erosion occurs, most of

the seed is generally washed off the slope, resulting in poor vegetation

establishment even if the microclimate is suitable.  After vegetation
is established, the need for mulch or other protection rapidly declines.

     Numerous investigators have concluded that a good mulch or similar
cover is essential to protect against erosion for the first few months
following construction.  Dyrness (66) found that test plots seeded
in early fall in Willamette National Forest in Oregon did not begin
vegetation growth until the following April and were not fully protected
by vegetation until June.  Of the various means of slope protection
studied by Dyrness, the only plots that showed consistently high
losses by surface erosion during vegetation establishment were the
unmulched plots.  It was also noted that dry season losses by ravelling
were almost as great as rain-caused soil loss.  Dyrness concluded
that mulching backslopes may be essential for reducing soil loss
to a minimum during the first few critical months following construction.

He also concluded that contrary to appearances, a luxuriant growth
of grass and legumes during the first growing season was not conclusive
evidence that soil loss was negligible during the preceding winter
months.
                                 177

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     Research conducted by Bethlahmy and Kidd (72)  in Boise  National




Forest, Idaho on 80 percent fill slopes yielded much the same results.




The results of their research are provided in Table 11.   Test plots




without treatment or with mechanical or chemical treatment combined




with seeding and fertilization lost soil at rates of 70,000 to 100,000




pounds per acre during the first 80 days after treatment.  Other




plots protected with mulch and mechanical treatment or mulch and




netting in addition to seeding and fertilization had soil losses




of less than 7,400 pounds per acre during this same period.




     In his study of the effectiveness of numerous  mulches and mulch




rates, Meyer (73) found that soil losses from simulated rainfall




on an unmulched plot was over 20 times that of well protected test




plots.  Other investigators, including Plass (71) and Barnett, et




al (74), have observed similar results.




     Research results, however, differ considerably over the value




of mulch protection to establishment of vegetative  cover.  Apparently,




this depends on the severity of environmental conditions.  In Oregon,




Dyrness (66) found that seeded but unmulched plots  produced good




vegetative cover and that mulch without seeding also produced good




vegetative cover.  Only the control plots without seeding or mulching




produced poor vegetative cover.  Similarly, Plass (71) tested the




effects of numerous mulches and chemical soil stabilizers on vegetative




establishment in the eastern United States and observed that some




mulches and chemical soil stabilizers improve the growth and vigor




of grasses, while some appear to have the opposite effect.
                                 178

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                               TABLE 11

COMPARISON OF CUMULATIVE EROSION FROM TREATED PLOTS ON A STEEP,  NEWLY
          CONSTRUCTED ROAD FILL (IN 1,000 LBS. PER ACRE) (72)

Cumulative : Cumulative : :
Elapsed : Precipita- : : Group A
Time : tion : Control: (Seed,
(days) : (inches) : Plot : Fertilizer
: Group B
: (Seed,
: Fertilizer,
): Mulch)
: Group C
: (Seed, Ferti-
: lizer, Mulch,
: Netting)
Plot Number
1
17
80
157
200
255
322
1.
4.
12.
15.
17.
20.
41
71
46
25
02
40
31.
70.
72.
79.
82.
84.
9
0
2
1
3
2
2
38.7
99.2
100.2
101.0
102.8
104.7
: 4
38.0
85.7
86.9
87.6
88.8
89.4
: 3
0.1
7.4
11.1
11.4
11.5
11.9
: 8
32.6
34.6
35.1
35.7
35.8
36.0
: 5 :
0
0.9
1.1
1.1
1.1
1.1
6
0
0
0
0
0
0
: 7
0
0.3
0.4
0.4
0.4
0.4
Description of Treatment Measures:
     Plot Number

          1
          2
          3

          4
          5
          6
          7
Type of Treatment

Control - no treatment at all.
Contour furrows, seed, fertilizer, holes.
Contour furrows, straw mulch, seed,
     fertilizer, holes.
Polymer emulsion, seed, fertilizer.
Straw mulch, paper netting, seed,  fertilizer.
Straw mulch, jute netting, seed, fertilizer.
Seed, fertilizer, straw mulch, chicken
     wire netting.
Seed, fertilizer, straw mulch with asphalt
     emulsion.
     Mechanical treatment - Contour furrows placed 6 feet apart and
          holes punched 2 inches deep at 6-inch intervals.

     Mulch and chemical soil stabilizer application rates - Straw mulch
          at 2 tons per acre.   Polymer emulsion at concentration of
          1 gallon Soil Set to 9 gallons of water.  Asphalt emulsion at
          rate of 300 gallons  per acre.
                                 179

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     In their tests, Meyer et al (73) concluded that good mulch protection

was necessary to establish vegetation.  Stands having more than 75

percent of the seedlings necessary for complete cover were established

on test plots mulched with 240 and 135 tons per acre stone, 12 tons

per acre woodchips, 70 tons per acre gravel, and straw-mulched slopes.

Unmulched plots, cement-stabilized plots,  and 15 tons per acre stone-

mulched plots had very little vegetation establishment.

     Other researchers have reached similar conclusions.   Heath (75)

reported that 50 to 90 percent of the seed planted on a slope is

saved from washing away when a mulch is used.  Diseker and Richardson

(76) have stated that using mulch over seedings often made the difference

between success and failure and that mulch was necessary on steep

slopes.  The question of need for mulch protection for vegetation

establishment is probably best summed up by Blaser (77) who concluded

that mulches aid in turf establishment, particularly under environmental

and moisture stress.

     Performance of Various Mulches and Chemiaal Soil Stabilizers.

The effectiveness of mulches and other soil stabilization measures

is a function of surface cover and overall lateral stability of the

protection network, including its ability to bind or penetrate into

the slope (73).  Erosive and other environmental stresses determine

the effectiveness of a particular treatment measure under a particular

set of circumstances.  A mulch rate or combination of mulch and other

stabilization measures may perform satisfactorily under one set of

circumstances and be completely ineffective under others.  The performance

of several types of mulch products in controlling erosion and establishing

vegetation under various conditions are compared in Tables 11 and

12 and Figure 21.
                                 180

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                              FIGURE 21

              SOIL LOSSES FROM A 35-FOOT LONG SLOPE (73)
                                      39.6   No Mulcha

                                             2 T/A Portland Cement

                                             2 T/A woodchipsa

                                             15 T/A stonea

                                             70 T/A gravel

                                             2.3 T/A straw

                                             60 T/A stone

                                             4 T/A woodchips

                                             7 T/A woodchipsa

                                             135 T/A stonea

                                             240 & 375 T/A stonea

                                             12 & 25 T/A woodchipsa
     0      10      20      30      40
     Soil Loss (T/A-tons per acre)
aBased on one replication only.  Values for other treatments based on
 average of two replications.

Soil Type:  6-inches silt loam topsoil underlain by compacted calcareous

     till (AASHO A-4) (Unified ML).

Slopes:  Uniform 20 percent

Rainfall Rate:

     Simulated rainfall at rate of 2 1/2 inches per hour - 1 hour

     the first day followed by two 30-minute applications the second day.

                                 181

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                               TABLE 12

             EROSION CONTROL AND VEGETATION ESTABLISHMENT
               EFFECTIVENESS OF VARIOUS MULCHES (78)1/
                                            Straw &             Wood
                  Jute   Excelsior   Straw   Asphalt   Asphalt   Fiber   Sod
Erosion Control

Sheet Erosion -
 1:1 slope        9.0      10.0       8.0     10.0       6.0      3.0    10.0

Sheet Erosion -
 2:1 slope        9.0      10.0      9.0      10.0       7.0      6.0    10.0

Sheet Erosion -
 3:1+ slope      10.0      10.0     10.0      10.0       9.0     10.0    10.0

Rill Erosion -
 1:1 slope        6.0      10.0      8.0      10.0       6.0      3.0    10.0

Rill Erosion -
 2:1 slope        8.0      10.0      9.0      10.0       7.0      5.0

Rill Erosion -
 3:1+ slope      10.0      10.0     10.0      10.0       9.0     10.0    10.0

Slump Erosion -
 1:1 slope       10.0       8.0      6.0       7.0       3.0      3.0     8.0

Slump Erosion -
 2:1 slope       10.0       9.0      7.0       8.0       5.0      4.0     9.0

Slump Erosion -
 3:1 slope                Slumps usually do not occur.

Vegetation Establishment

 1.5:1 glacial
     till cut
     slope        7.5       9.0      7.5       8.5       7.5      6.0

 2:1 glacial
     till cut
     slope        8.9       9.5      8.0       9.3       8.7      6.2

 2:1 sandy loam
     fill slope   9.0      10.0      9.0      10.0       7.5      8.5    10.0

 2.5:1 silt loam
     cut slope    5.0      10.0       -        7.8       6.0

I/Effectiveness rating: 10.0 = most effective,1.0 = not effective.
                                     182

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                           TABLE 12 (cont.)




Location:  Highways in eastern and western Washington.




Slopes:  1.5:1 to 3:1+ cut and fill slopes.




Soils:  Silty, sandy and gravelly loams; and glacial till consisting of




     sand, gravel and compacted silts and clays.  All are subsoil




     materials without topsoil addition.




Slope Lengths:  Apparently maximum of 165 feet.




Application Rates:




     Cereal straw - 2 tons/acre




     Straw plus asphalt - 2 tons/acre straw plus asphalt at rate of




       200 gal/ton of straw (one test at rate of 100 gal/ton of straw)




     Asphalt alone - .20 gal/sq.  yd. (968 gal/ac)




     Wood cellulose fiber - 1,200 Ibs/ac.




     Sod - bentgrass strips 18 inches by 6 feet pegged down every




       third row.







     Straw (or hay) is one of the oldest and probably by far the most




commonly used form of mulch material.   Straw mulch has proven to be




quite effective if slope gradient,  slope length, and rainfall intensity




are not excessive.  In his studies,  Dyrness (66) found straw mulch



applied at a rate of 2 tons per acre to be relatively effective in




reducing erosion.  Bethlahmy and  Kidd (72) found straw mulch to be




quite effective when supplemented by mechanical treatment measures




or netting (Table 11).   Goss et al  (78) have noted that straw mulch




alone is moderately effective in  a  number of erosion-prevention




applications but that its effectiveness is improved when used in




combination with an asphalt tack  (Table 12).   Straw plus asphalt





                                183

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emulsion was found to be one of the most effective mulches in controlling




erosion and establishing vegetation.  Meyer et al (73) indicated




that straw mulch is moderately effective in preventing erosion but




that its performance is considerably exceeded by suitably heavy applications




of other mulches (Figure 21).




     Several researchers, including Meyer et al (73),  have observed




a breakdown of straw mulches due to rill formation.  Besides problems




with rill formation, straw mulches must also be protected from strong




winds (58, 78).  Chemical stabilizers, mechanical measures such as




contour furrowing, and application of netting over the mulch can




be used to improve attachment of mulch to the slope,  thus guarding




against both rill formation and wind erosion.




     Chemical stabilizers, used as the sole means of slope protection,




generally cannot be relied upon to be as effective as several other




measures (Tables 11 and 12).  However, use of chemical stabilizers




in combination with mulches, or as a minimum with wood fibers added,




generally increases their effectiveness significantly in controlling




erosion and encouraging vegetation establishment (71,  78).




     Chemical soil stabilizers, by virtue of their chemical composition,




can affect vegetation establishment.  Plass (71) reported that some




treatments improve growth and vigor of vegetation, while others have




an adverse effect.  Adverse effects of some products on vegetation




establishment have also been noted by the Washington State Highway




Department (79).




     A wide variety of chemical stabilizers, probably totalling 40




or more, with differing performance levels under differing environmental




                                 184

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conditions are available.  Of the numerous products available some




may exceed the performance capability of commonly used mulches such




as straw.  The chemical soil stabilization field is rapidly developing




with new products being introduced frequently.  With continuing develop-




ments, this field appears to offer good potential for the future.




     Commercially available combination mulch-netting products are




available.  Some of these products have proven relatively effective,




even under severe conditions.  Except for sod protection, Goss et al




(Table 12) found one such product (Excelsior) to be the most consistently




effective product tested for both erosion control and vegetation




establishment.  Plass (71) has also found some of these products




to be quite effective.  However, the material and installation costs




may be too high to warrant their use for forest road application, except




in the most severely stressed areas.  Similar products, such as jute




netting, are also effective in preventing erosion.  Use of jute netting




is particularly attractive where high tensile strengths are needed




to protect against shallow surface slump erosion during the initial




postconstruction period before natural consolidation processes can act




to increase the soil strength (Table 12).  Good attachment of netting-




type materials to the slope is of prime importance to prevent rill




erosion underneath.  Jute, for instance, has sufficient strength




to bridge even large rills and allow erosion to continue unchecked (78).




     Meyer et al (Figure 21) have found gravel and crushed stone




mulches to be quite effective, even under relatively severe conditions.




Various application rates of stone and gravel mulches were found




to be considerably more effective than 2 tons per acre of straw mulch.




Resistance to rill formation is a prime advantage of stone and gravel




                                185

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mulches.  They tend to impede rill formation by sloughing into them,




rather than bridging them as do straw mulches or being washed down




the slope as do woodchip mulches when subjected to severe erosive




stresses.  Meyer et al found a rate of application of 135 tons per




acre of stone mulch, which averages less than 1-inch depth,  to be




effective under all conditions tested (73).




     Stone mulches also appear to have other advantages.   Meyer et




al found that grass stands on inert stone and gravel plots were much




more vigorous than those on the woodchip and particularly the straw




plots where grasses showed symptoms of a nitrogen deficiency.  Also,




unlike straw and other mulches, stone mulches are not subject to




rapid decomposition.  Their resistance to decay makes them uniquely




valuable for permanent applications where vegetation cannot  be established.




     Woodchip mulches appear to have promise for forest applications.




Along with stone mulches, Meyer et al (Figure 21) found woodchip




mulches to be a good mulch material if applied at adequate rates.




Woodchip mulch at the rate of 4 tons per acre was found to be more



effective on 35-foot long slopes than 2 tons per acre straw mulch.




Woodchip application at a rate of 25 tons per acre (1J inches depth)




offered good protection under relatively severe conditions of 20




percent slopes as long as 160 feet (73).  Crabtree (80) found 5 tons




per acre of woodchip mulch to be quite effective on 3 to 1 slopes




in Iowa.  Woodchip mulches are relatively long lasting compared to




other mulches such as straw or hay, require no tacking to hold them




in place, and the raw materials for their manufacture are readily




available in forested areas.





                                186

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     An adequate rate of woodchip application and uniform distribution




of the mulch material is particularly important.  Meyer et al (73)




noted that the consequences of breakdown are more serious for woodchip




mulches than for stone, gravel, and straw mulches.  When a woodchip




mulch broke down, woodchips were grossly displaced and large, deep




rills developed.  Anchoring the woodchips with asphalt or other materials




might improve their performance at some application rates (81).




     As mentioned previously, vegetation on woodchip mulched slopes




generally exhibits a nitrogen deficiency.  Application of about 20




pounds of additional nitrogen per air dry ton of mulch is required




when wood products are used.




     Wood fibers have proven beneficial in preventing erosion when




used alone or in combination with chemical soil stabilizers.  The




Washington State Highway Department has found that wood cellulose




fiber, particularly when used in combination with chemical binding




agents to enable them to better resist wind erosion, is an economical




and successful alternative in western Washington where straw is not




readily available (79).  A University of California study (63) of




hydroseeding on clay-loam soils reported soil losses of 0, 1,000,




and 9,000 pounds per acre from plots with wood cellulose fibers applied




at rates of 3,000,  2,000, and 1,000 pounds per acre, respectively,




compared with losses of 81,000 pounds per acre where no fiber was




applied.  On the fiber-treated areas, there were 300, 262, and 86




grass seedlings per square foot compared with none on areas without




fiber treatment.   Plass (71) reported that plots treated with soil




stabilizers lacking wood fibers generally did not have as tall or




dense vegetative cover as when stabilizers with wood fibers and other




                                187

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mulch products were used.  Plass noted that there is a growing trend




toward incorporating wood fibers into soil stabilizers to increase




their effectiveness.




     Others have reported less favorably on the use of wood fiber




for slope protection.  Goss et al found that wood fiber does not




have sufficient damming ability nor tensile strength to prevent erosion




on long slopes, particularly if steeper than 3 to 1 (78).  Crabtree




(80) found when wood fiber was applied at rates of 1,000 to 1,400




pounds per acre on 3 to 1 slopes in Iowa, it was only poorly to moderately




effective in checking erosion.






Mechanical Treatment




     Introduction.  Mechanical measures can inhibit erosion on slopes.




Several such measures are currently being successfully used.  They




consist of diversions and terraces, either atop or on slope faces;




serrations or other variations in gradient; and roughening or scarification




of the slope.  Although most of these measures can be used individually




for slope protection, their primary purpose is to supplement mulches




and other forms of  slope stabilization.



     Mechanical slope stabilization measures generally function by




reducing the volume  and velocity of surface runoff through a reduction




of effective slope  length and -an increase in infiltration.  These




measures can also prevent concentration  of flow in erodible areas




and provide an improved microclimate for vegetation establishment.




     Although numerous references  suggest the usage of or describe




many of these mechanical measures  in a general way, very little  specific




information is provided  on their application, design, and effectiveness.




                                188

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Specific design criteria must generally "be developed on an individual




basis.  Descriptions of the various mechanical measures in common




usage are provided in the remainder of this section.




     Diversions or Terraces.  Diversions and terraces are channels




with a supporting ridge on the lower side constructed across or atop




cut or fill slopes.  Terraces are generally level and have closed




ends to retain the runoff, while diversions are designed to carry




water at nonerosive velocities to planned disposal areas.  Their




purpose is to intercept surface or shallow subsurface runoff and




store it or divert it to an outlet where it can be safely disposed




of.  They can reduce slope length into nonerosive segments or divert




water away from critical areas.




     Terraces and diversions are not applicable for some soils on




steep slopes.  During periods of high moisture inflow terraces can




become saturated,  leading to slump failures.   Use of terraces on




slopes exceeding approximately 40 percent is not recommended in the




Idaho Batholith.




     Diversion outlets should be located where water will empty into




natural drainage channels or into relatively low-gradient upland




areas between drainage channels.  Care must be exercised to avoid




excessive flow concentration or erosive velocities when conveying




or discharging water.  Buffer strips of vegetation between points




of discharge and stream courses are extremely desirable to allow




sediment to deposit.




     Serrations.  Serrations are steps or benches in steep slopes.




The areas between the steps are generally constructed vertical,  although




                                189

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they can be sloped.  If properly located and designed,  serrations



reduce slope length and divide the volume of runoff into workable



slugs that can be more easily handled.   They are usually constructed



level to retain precipitation in place,  but they can be graded with



a longitudinal gradient and an outside  edge higher than the inside



to function as diversions.



     In addition to their function of retarding runoff, benches provided



by serrations also improve the microclimate for vegetation establishment



on steep slopes.  The flat areas better enable vegetation to gain a




foothold.



     Serrated slopes are a relatively new method of erosion control




and are only applicable under certain conditions.  These conditions



include cut slopes of soft rock or similar material that will stand



vertically or near-vertically for a few years in cut heights of approxi-



mately a couple of feet.  Several states, including the highway



departments of Washington (82) and Idaho, are currently using this



method successfully in selected areas.



     Serrations generally consist of steps of 2 to 4 feet cut vertically



and horizontally along the normal, intended slope gradient.  After



construction, the slope is seeded, fertilized, and mulched as with



normal slopes.  The horizontal areas provide an improved environment



for vegetation establishment, free of sliding forces normally experienced



on steep slopes.  The steps gradually slough and practically disappear



within a few years following construction, generally after vegetation




has become well established.  If the slope material is soft, the



slope should be allowed to slough before seeding until about one-third




                                190

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 of  the  steps  are  filled.   Otherwise, grass may be destroyed by the




 excessive  rate  of initial  slough.  This method is not applicable




 to  soil types where  the rate  of  slough is so high that vegetative




 cover is buried and  destroyed.




     Roughness  and Scarification.  Smoothly graded cut-and-fill slopes




 are attractive  to the eye, but they do not benefit erosion control




 and establishment of vegetative  cover.  Roughness and scarification




 serve to increase infiltration and impede runoff (58).  If the surface




 is  to be seeded,  the roughness or scarification marks retain seed




 even after severe runoff.  These measures also help mulch adhere




 better  to  the slope.




     Slopes may be roughened by a wide variety of construction methods.




 Soils can  be  scarified with a bladed implement having a ripper




 attachment which  loosens surface soils in place without turning them




 over.   Deep-cleated  dozers traveling up and down the slope can be




 used to obtain  a  satisfactory texture on slopes that are too steep




 for normal equipment operation.  The Washington Highway Department




 (79) has found  that  a sheepsfoot roller works well for roughening



 slopes.




     The texture  of the roughened slope should trend perpendicular




 to the  flow direction (58).  Up and down or angular cross slope roughness




 texture  causes  flow  concentration,  which is harmful.   Also,  care




must be exercised to prevent excessive loosening of the upper soils




 such that  the propensity for rill and slump erosion are increased.
                                 191

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MASS WASTING




     Mass wasting is the primary cause of stream sedimentation in




many areas of EPA, Region X.   Mass wasting problems are most common




in the coastal regions where  rainfall is greatest,  but they are by




no means limited to these areas (2, 6, 24).




     Mass wasting occurs when gravitational and other forces,  such




as seepage or seismic, which  act on a soil or rock mass are greater




than the strength which can be mobilized within the mass.   The resulting




instability usually involves  a net downward migration of the mass




until a condition of temporary or permanent equilibrium is attained.




     The two primary forms of mass failure are (l) deep, rotational




types of soil movement, including slumps and earthflows, and (2)




shallow debris movements, including rockslides, debris avalanches,




and debris flows.  The latter type of movement is more common in




mountainous forested areas.  Debris movements are likely to develop




suddenly in bedded sediments  or on shallow,  relatively coarse-textured,




cohesionless soils on steep hillsides.  They are characterized by




rapid downslope movement of fractured rock,  soil, and/or organic




material along a slip surface roughly parallel to the topographic




surface.  Large rotational slumps, earthflows, or soil creep are




most likely to occur in deep, saturated, fine-textured soils on more




moderate slopes (19).  These  will normally extend over a lesser area.




Slumps and earthflows are relatively fast moving, but may be preceded




or followed by soil creep which can occur over a very long period.




     Many factors are responsible for mass failures along logging




roads.  In some cases, a specific factor can be isolated,  but usually



                                192

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a failure is caused by several interrelated factors.  By far the




greatest proportion of these influences along logging roads are directly




or indirectly related to human activity.  Specific factors include




undercutting of unstable or marginally stable slopes, oversteepening




of cut and fill slopes, sidecasting of excavated materials on steep




slopes, improper embankment construction (particularly compaction),




and drainage system failures (3> 5, 19).




     Often the basic causes of mass failures are "overroading" and




"overdesign."  Overroading or misplacement of roads results from




a poor land management or transportation plan.  Overdesign of roads




results from rigid application of design criteria regarding curvature,




width, gradient, and cut and fill slope steepness; or design of roads




to higher standards than required for their primary intended uses.




By lowering design standards when possible and allowing flexibility




in application of alignment, width, grade, and other design criteria,




many mass wasting problems can be avoided (6, 19).  This is particularly




true where it is possible to reduce cut and fill slope heights or




roadway widths.




     The maximum control of mass wastage is achieved by concentrating




on preventive measures prior to and during construction rather than




attempting to control problems after the fact.  The control of sedimentation




resulting from mass movement near a stream is virtually impossible




once the mass movement has occurred.  Minimization of mass wastage




can take place only by thorough planning and reconnaissance investigation?




as discussed in previous sections.






                                193

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     Unfortunately, of all causes of stream sedimentation,  mass movement




is the most difficult to predict in advance.  No precise universal




rules can be developed relating the main causative factors  of slope




steepness, soil strength, and groundwater conditions.   Many predictive




methodologies have been developed for local areas but  they  are based




on empirical, or at best semiempirical, factors and usually require




modification before they can be applied to areas other than for which




they were developed (20, 23).  Additional research is  needed to improve




methods for mass wastage prediction.




     Mass wasting problems rarely can be completely avoided.  Even




with the best of planning and reconnaissance investigations to avoid




unstable conditions, a few problems are likely to develop in all




but the most stable areas.  In other cases, it may be  necessary to




locate roads in unstable areas because of a lack of feasible alternatives.




This can result in serious mass wasting problems unless corrective




measures are included in road design.




     Many of the potential means of slope stabilization, both structural




and nonstructural, and their possible applications are discussed




in the remainder of this section.  The selection of the proper corrective




action to be used in any given situation depends upon the nature




of the problem, the foundation conditions at the site, and economic




considerations.  No attempt is made to provide specific design recommendations




or procedures since the actual design of corrective measures is heavily




dependent upon the conditions at each location.




     The adequate design of structural retention systems involves




a high level of professional skill.  All designs should include




                                194

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engineering analysis by personnel experienced in soil and rock mechanics.




In most cases, design should be preceded by detailed geotechnical




investigations to assess the conditions at each site.






Retaining Walls




     Retaining walls are used to bring about an abrupt change in




grade or to enable the utilization of a steeper overall slope than




would otherwise be possible in a particular soil or rock mass.  Several




types of retaining walls are available.  Among the basic types are




gravity walls, crib walls, and cantilever walls.




     Gravity walls or buttresses are usually constructed of plain




masonry, rock rubble, stone, or concrete.  The weight of the structure




acts to counterbalance and resist earth pressures.  This type of




wall is usually the simplest and easiest to construct but generally




can be used only for relatively low walls (less than 8 to 10 feet




in height) with moderate soil pressures (83).




     A crib wall is essentially a gravity-type structure made of




timber, precast concrete or metal which forms an open structure of




some dimension.  When this open structure is filled with soil, it




becomes relatively large and massive.  This type of wall is usually




suitable for small- to moderate-height walls (less than 20 feet in




height) subjected to only moderate earth pressures (83).  Crib walls




are usually flexible enough to be used where settlement is a particular




problem.




     There are three basic kinds of cantilever walls.  The first




kind is a plain cantilever wall that can be used for heights up to




approximately 25 feet.  These walls usually consist of a reinforced




                                195

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concrete stem founded on a reinforced concrete base slab.  The other




two kinds are modifications of a cantilever where counterforts or




buttresses are added to the wall.  The counterforts or buttresses




add strength to the stem portion of the wall and a degree of rigidity




to the entire wall.  These additions may be used for walls higher




than 25 feet with most soil conditions (83).




     All retention walls are expensive to design and construct.




Of the various forms discussed, crib walls are probably cheapest




for forest applications.  The great expense of retaining walls reemphasizes




the need to study all possible alternatives to the location of roads




in areas of potential mass wastage.






Bulkheads




     In cases where soil conditions permit, use of sheet pile bulkheads




may be advisable.  The sheet piles may either be cantilevered or




restrained near the top with anchors.  In either case, relatively




deep penetration into the soil mass is required to ensure stability




of the bulkhead.  This method of retention is often expensive.  However,




installation of a cantilever bulkhead is relatively simple and can




be done without form work.  These walls are usually less than 20




feet in height and include the installation of drainage measures




behind the wall (8/4).






Reinforced Earth




     Construction of reinforced earth structures consists of placing




metal strips perpendicular to the front of either a thin shell concrete




or steel wall.  Soil is then compacted over the strips for a shallow




                                196

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depth, another set of strips is then placed, and the process repeated




until the full height of the wall is attained.  This process is restricted




to granular backfills and to walls usually less than 15 feet in height.






Rock Rubble Facing




     Slope embankments may be lined with rock rubble to protect against




shallow surface slumping.  Rock rubble protects the slope face from




the effects of weathering and provides a ready outlet for groundwater




seepage.  Surface erosion is also prevented.  However, it should




be realized that rock rubble, unless applied in large enough quantities




to act as a gravity-type retaining wall, offers no significant protection




against deep-seated or avalanche-type slide failures.






Lowering Groundwater Levels




     Groundwater conditions contribute heavily to slope instability.




As the water table rises, buoyant forces on the individual soil




particles reduce their interlocking strengths and thus the frictional




resistance to sliding.  The improvement of surface drainage is one




of the cheapest and most effective techniques of lowering groundwater




levels and one that is often overlooked.  Sag ponds and depressions




can be connected to the nearest stream channel with ditches excavated




by bulldozers or other means.  Improved surface drainage removes




water quickly, lowers the groundwater level, and helps stabilize




slumps (19).




     Another technique is to lower the groundwater level by means




of perforated pipes installed in drill holes augered into the slope




at a slight upward angle.  Such drains are usually installed in road




                                197

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cut "banks to stabilize areas above an existing road, or below roads




to stabilize fills.  Installation of perforated pipe is relatively




expensive and there is a risk that slight shifts in the slump mass




may render the pipe ineffective.  In addition, periodic cleaning




of these pipes is necessary to prevent blockage by algae, soil, or




iron deposits (19, 85).




     A third technique of lowering groundwater levels is installation




of an interceptor drain to collect groundwater moving laterally downslope




and under the road.  A backhoe can be used to install interceptor




drains in the ditch along the upslope side of the road (19).  The




drain can consist entirely of  graded granular materials with gradations




sufficient to carry the intercepted flow efficiently without becoming




plugged with fine native soils; or, preferably, a perforated pipe




bedded in granular material.






Deep Rooted Vegetation




     The effect of tree root strength on slope stability is not fully




understood.  However, results of research studies indicate that living




tree roots help maintain slope stability.  Reports by the Forest




Service from southeast Alaska indicate that the number of landslides




from cut-over areas increases within 3 to 5 years after logging.




This increase is attributed to a reduction in soil shear strength




caused by the decay of tree roots following logging.  The presence




of living tree roots to anchor shallow soils to the underlying subsoil




appears to be particularly important in small drainages where winter




storms can cause the groundwater level to rise sharply (24).  Similar






                                 198

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observations have been noted in other areas (6, 20).  A contributing




factor to gain of soil strength with deep rooted vegetation establishment




may be lowering of groundwater levels as a result of water uptake.






Fill Placement




     Many measures can be utilized to increase the stability of fill




embankments.  One of these is proper keying of the embankment to




the slope through removal of all vegetation and organic material




from the existing surface and scarification of the underlying native




soils.  On steeper side slopes the excavation of a slot or keyway




just ahead of the fill will help to prevent the formation of a failure




surface at the interface of the embankment and the slope.  The stability




of an embankment can be greatly enhanced by compaction of the fill




to engineering standards, with special attention given to maintaining




proper lift thickness, moisture content, and quality of the fill




materials (e.g. exclusion of organic debris, etc.).  Studies of mass




failures in the Idaho Batholith revealed that liquefaction of fill




embankments attributed to minimal compactive effort was the triggering




factor in some embankment failures (6).




     Fills should not be placed on steep slopes that are themselves




marginally stable.  Both avalanche-type failures on the hillside below



the slope and deep-seated failures either on the upslope or downslope




sections of the road can occur.  Avalanche-type failures or deep-seated




failures of the lower road section are particularly likely if excavated




material is sidecast.  End-hauling of excavated material to stable




areas is necessary to reduce overloading of unstable slopes to an




absolute minimum (19).




                                 199

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                          DRAINAGE DESIGN


     "A major contributor to both accelerated surface soil erosion and
     mass soil failures was lack of adequate drainage provided at man-
     made improvements.  Drainage includes practices that prevent con-
     centration of water and those that foster dispersal of water into
     stabilized land areas or into stabilized stream channels.   Failure
     or impairment of road drainage facilities was involved in almost
     all road-connected storm damage" (ll).

To minimize sediment production and transportation from forest roads,

the planning, design and construction of drainage facilities must be

executed for the particular conditions encountered and not on a basis

of generalized criteria.

     The Maintenance chapter of this section discusses drainage mainte-

nance but designers and owners should recognize that the designs and

suggestions contained under this heading will not function adequately

without inspection, maintenance and possible change of individual drain-

age features.  The first such inspections should be made, hopefully by

the design engineer, during or immediately after the first storm.


DITCHES AND BERMS


     The two primary functions of ditches and berms are to intercept

runoff before it reaches erodible areas, and to carry sediment, during

high flows, to properly designed settling basins when circumstances

warrant the use of these basins.  Important places to install ditches

or berms are at the top of cut and fill slopes and adjacent to the road-

way.  Midslope berms with ditches may be especially helpful in con-

trolling sediment before erosion control cover is established.

     The ditch size (area) can be determined by considering the slope

of the ditch, area intercepted, estimated intensity and volume of run-
                                  200

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off, and the amount of sediment that may be deposited in the ditch




during low flow conditions.  The shape of the ditch may "be trapezoidal




or triangular, whichever is appropriate to the particular location.






Size and Placement






     For ditch design, a good reference is "Design Charts for Open




Channel Flow," Hydraulic Design Series No. 3, by the Bureau of Public




Roads, (Federal Highway Administration) 1961 or later revision (86).




In addition to the ditch size required for full flow capacity, an allow-




ance should be made for anticipated sediment deposit.  Minimum full




capacity flow velocities should be 2.5 to 3.0 feet per second to permit




sediment transport.  Refer to Table 13 for scour velocities in ditches




of various materials.




     The depth of potential sediment deposit in ditches is directly




related to the erodibility of the soils over which water flows to the




ditch and the ditch slope.  The ditch depth allowance for sediment




deposit should recognize the soil erodibility, the kind of erosion con-




trol cover planned for tributary slopes and the anticipated maintenance




program.  Some ditches, due to their slope and/or soil type, may not




require a depth allowance for sediment build-up.  The designer should




refer to the information obtained during the planning-reconnaissance




phase of the project for data relating to the erodibility of the soils




that will be encountered within the road corridor.




     All ditches constructed in erodible soils are themselves subject to




erosion from runoff and may require stabilization by such means as rip-




rap, rock rubble lining, jute matting, seeding and/or other acceptable






                                  201

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                              TABKB 13—
Maximum permissible velocities in erodible channels,  based on uniform
flow in continuously wet, aged channels
                                            Maximum permissible
                                              velocities for—
Material






Sandy loam (noncolloidal) 	
Silt loam (noncolloidal) 	


Fine gravel 	
Stiff clay (very colloidal) 	
Graded, loam to cobbles (noncolloidal) .
Graded, silt to cobbles (colloidal). . .
Alluvial silts (noncolloidal) 	
Alluvial silts (colloidal) 	
Coarse gravel (noncolloidal) . 	

Shales and hard pans 	



Clear
water

F.p.s.
1.5
1.7
2.0
2.5
2.5
2.5
3.7
3.7
4.0
2.0
3.7
4.0
5.0
6.0


Water
carrying
fine
silts
F.p.s.
2.5
2.5
3.0
3.5
3.5
5.0
5.0
5.0
5.5
3.5
5.0
6.0
5.5
6.0


Water
carrying
sand and
gravel
F.p.s.
1.5
2 0
2.0
2.2
2.0
3.7
3.0
5.0
5.0
2.0
3.0
6.5
6.5
5.0

 — As recommended by Special Committee on Irrigation Research,  American
Society of Civil Engineers, 1926, for channels with straight alinement.
For sinuous channels multiply allowable velocity by 0.95 for slightly
sinous, by 0.9 for moderately sinuous channels, and by 0.8 for highly
sinous channels (45, p. 1257)
Source:  Design of Roadside Drainage Channels, U. S. Department of
Commerce, Bureau of Public Roads V/ashington:  1965,  page 54.
                                  202

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erosion control device.  Plastic sheeting can be used as  a  temporary

erosion control device during the construction period.

     Riprap or rubble lined ditches will tend to act as a flow retard-

ent which will allow movement of water and retain the sediment at  low

flow periods.  The depth allowance for ditches lined with riprap or

rock rubble can coincide with the depth allowance for sediment deposit.

     The full flow water surface for roadway ditches should be at  least

one foot below the roadway subgrade.  This position will  prevent ditch

water from entering the ballast material, removing the fines and de-

stroying the ballast's effectiveness in supporting the roadway surface.

Figure 22 show's the water surface level relative to the road subgrade.
                                                                   , If used
                  DITCH WATER SURFACE-ROAD SUBGRADE
                              FIGURE 22
     The suggested minimum size of interceptor ditches  is  shown  in

Figure 23.

     Berms (Figure 24) can be constructed of native material provided

that the material contains enough fines to make the berm impervious

and the material can be shaped and compacted to about 90$  of maximum
                                  203

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TRAPEZOIDAL
TRIANGULAR
          MINIMUM INTERCEPTOR DITCH SIZE




                  FIGURE 23
                     BERM




                   FIGURE 24
                     204

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 density.—  An extruded asphalt or portland cement concrete curb can

 also be used to intercept water at the roadway shoulder edge.  The curb

 occupies less room than does a berm.

      Figure 25 portrays the general location for ditches and berms in

 relation to a finished roadway section.  Additional locations for temp-

 orary ditches and other drainage facilities may be necessary during the

 construction phase.  Refer to the Construction chapter.

      Ditches at the top of slopes may be needed when:

      1.  The natural ground above slope "daylight" point continues up

          sharply.

      2.  Ground cover above "daylight" point has low moisture absorbing

          ability.

      3.  Exposed soils on cut slope are highly erodible, the exposed

          area is large, rain intensities are high and erosion control

          measures need time for establishment.

      4.  Quantity of runoff will flood or tend to flood the roadway

          ditch below the cut slope.


 Ditch Profiles


      Roadway ditch profiles will generally follow the roadway grade.  The

 minimum grade should be 1 percent.  If flatter grades are necessary,

 ditches may need to be larger or alternately, the ditch can be separate-

 ly profiled to obtain the necessary minimum gradient.


— Maximum density is a term used in earthwork specifications to mean the
 oven-dry weight per cubic foot of soil at optimum moisture content.  The
 American Association of State Highway Officials (AASHO), the American
 Society of Testing Materials (ASTM) and other organizations have estab-
 lished field testing procedures to determine if compacted earthwork
 meets a specified percentage of maximum density.
                                   205

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                                di+ch or
                               curb
DITCH PLACEMENT

   FIGURE 25
                                Bas/h
                         DITCH OUTLET NEAR
                              STREAM
     206

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     Other ditch profiles should "be consistent with the ditch section




used and quantity of flow.  As previously suggested, the full flow




velocity in all ditches should be at least 2.5 to 3.0 feet per second




to permit sediment transport.






Ditch Outlets






     Ditches will outlet or discharge into natural streams, other drain-




age channels, culverts or settling basins.  Ditches that outlet into




natural drainage channels or streams may require a catch basin with cul-




vert outlet or other sediment trapping device, 100-150 feet upstream from




the intersection with the drainage channel or stream as shown in Figure




26.  If the roadway cut slopes, fill slopes and ditches are stabilized,




there should be minimal risk of sediment entering the stream or natural




channel from the last 100-150 feet of the ditch shown in Figure 26.




     Ditches also outlet into culverts.  If the soils are erodible in




and around the ditch, the circumstances may require a catch basin struc-




ture prior to culvert entry.  See the following discussion on culverts




and catch basins.






Sloped Roadway Alternate to Roadside Ditches






     Construction of out and in sloped roadways with surface cross




drains has been a popular way to build forest roads.  Although this




type of construction has a place in forest road work, misuse of the




concept can result in a sediment problem.




     From the "Proceedings of A Symposium Forest Land Uses and Stream




Environment" at Oregon State University, Larse recommends:  "Design out-






                                  207

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slope or alternating inslope and outslope roadbed sections without a

drainage ditch when overland surface flows are slight and road gradients

can be 'rolled' sufficiently to self-drain without surface channeling"(5).

     Packer studied the control of rill or gully erosion on outslope

road surfaces in the Northern Rocky Mountains (56).  Each study site

had to meet the following criteria:

     1.  "Drainage structures immediately above and immediately below
         the road segment must have diverted all surface runoff and
         eroded soil originating above them onto the fill slope below
         the road without allowing any discharge to continue down the
         road surface."

     2.  "The road segment must not have been affected by waterflow
         from side drainages."

     3.  "The road segment must not have had an inside ditch along the
         toe of the road cut."

     4.  "Sediment discharged from the lower or downgrade drainage
         structure, or eroded from the fill below it, must have been
         stopped on the slope before reaching a stream channel, a
         downslope road, or a major topographic barrier, such as a
         bench."

     5.  "The entire study site, including the slope above the road cut
         and the slope below the fill, must have been located on soil
         derived from similar parent material."

     6.  "The site must have been on an area where the timber sale was
         not more than 5 years old."

The report included a table for cross drain spacing required to prevent

rill or gully erosion deeper than one inch on secondary logging roads in

certain types of soils on various road grades.  The Guides for Control-

ling Sediment from Secondary Logging Roads by Packer and Christensen

also contains the table.  The table is included herein as Table 14.

Care must be exercised in the use of the table to ascertain that it is

applied under circumstances that are closely comparable to the conditions

under which Packer's studies were made.  Packer and Christensen recommend
                                  208

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                              TABLE
Cross-drain spacings required to prevent rill or gully erosion deeper than
1 inch on secondary logging roads built in the upper topographic position
(1) of north-facing slopes (2) having a gradient of 80 percent.  (3)
  Road
                          Cross-drain spacing
 grade         Hard                         Glacial
(percent)    sediment   Basalt    Granite     silt
Andesite   Loess
2
4
6
8
10
12
14
167
152
144
137
128
119
108
154
139
131
124
115
106
95
137
122
114
107
98
89
78
135
120
112
105
96
87
76
105
90
82
75
66
57
46
95
80
72
65
57
48
37
(l) On middle topographic position, reduce spacings 18 feet;  on lower
topographic position, reduce spacings 36 feet.
(2) On south aspects, reduce spacings 15 feet.
(3) For each 10-percent decrease in slope steepness below 80  percent,
reduce spacings 5 feet.
Source:  Packer, Paul E., "Criteria for Designing and Locating Logging
         Roads to Control Sediment," reprinted from Forest Science,
         Volume 13, Number 1,  March, 1967.
                                 209

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that where combination of soil and topographic features require cross

drain spacings of less than thirty feet, "no logging roads should be

built unless they will be surfaced with gravel or crushed rock" (4-6).

     In their China Glenn road report, Hartsog and Gonsior offer the

following conclusion as to the success of the outslope road section as

used at this particular location:

     "The authors suspect that outsloping is more an idealistic concept
     than a realistic solution to the water control problem.   In theory,
     water generally will be uniformly distributed in minimal concentra-
     tion over the road shoulder.  However, unless the road can be
     graded to close tolerances and left undistorted,  concentration is
     virtually unavoidable.   Depressions left by wheels allow water to
     concentrate and run along the road.  Even if the road has no grade,
     water will tend to concentrate and spill over depressions.  If
     soils are loose and erodible, slight concentrations tend to erode
     depressions and channels that lead to greater concentrations and
     accelerated erosion.  Although it can be argued that such problems
     rarely occur, the major part of all stream sedimentation is caused
     by relatively infrequent circumstances.  Most of any stream's an-
     nual sediment load is contributed and transmitted (under natural or
     disturbed conditions) during a few hours or days.   It is tentatively
     recommended that outsloping be specified only where surfaces are
     relatively nonerodible (e.g., at full-bench sections)" (14).

     The following conditions are favorable for the use of no ditch out-

slope roads with surface cross drains.

     1.  Short backslopes.

     2.  Terrain slope less than 20 percent.

     3.  Seasonal road use.

     4.  Spur (light traffic) roads.

     5.  Favorable geographic area.

     6.  Non continuous longitudinal grades steeper than 3 percent.

     7.  Conditions permitting immediate planting and growing of

         vegetation on cut and fill slopes.

     The following conditions are unfavorable for the use of no ditch

outslope roads.

                                  210

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     1.  Long backslopes.




     2.  Continuous steep  longitudinal  grades.




     3.  Terrain steeper than  20 percent.






Rock Sub-drain Alternate to Roadside Ditches






     Another alternate is  the  use of  the rock  sub-drain.   The  rock sub-




drain is located between the toe of the cut  slope  and the  edge of the




roadway, as shown on Figure 27.  An advantage  for  its use  as compared to




an open ditch is that the  total grading width  of the  road  will be less.
                           ROCK SUB-DRAIN




                             FIGURE 27
Rock sub-drains may be used when longitudinal grades  are  steeper  than 2




percent.  Critical to the longevity of the sub-drain  is the  establishment





                                  211

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and maintenance of vegetation on the slopes above the drain.  Any limita-




tions on construction procedures for installing the rock sub-drain in




order to maintain backslope stability and prevent contamination of the




sub-drain should be included on the plans or in the accompanying speci-



fications.




     Rock sub-drains can outlet similarly to the open ditch, through a




Ditch Inlet Structure, as discussed in the next part, and a cross culvert




or to a natural channel.






CULVERTS






     "A culvert is an enclosed channel serving as a continuation of and




a substitute for an open ditch or an open stream where that ditch or




stream meets an artificial barrier such as a roadway, embankment or




levee" (87).  Forest road culverts are used primarily to drain the road-




way surface (outletting roadside ditches) and to allow streams or natural




channels to pass through a roadway embankment.




     "Culvert failure, another common cause of road damage, was most




often related to plugging with debris.  In most cases, the hydraulic




capacity of the culvert was sufficient to carry the volume of water as




long as it remained unplugged" (11).




     The fact that culvert intakes do become blocked with debris, sedi-




ment, rocks, etc., requires that serious consideration be accorded the




use of a culvert intake protecting device.  A Ditch Grating Inlet Struc-




ture, with or without a Catch Basin (Figures 28 and 29), is such a




device.  The degree or amount of culvert intake protection needed will




vary with individual site circumstances from a simple riprap treatment




of ditch bottom and sides at the intake point to the more elaborate




                                  212

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                           8-4.
V)
                         ' /
                        //
                     //*- Cu/vert-
                     /
                                                  Oitch
                           PLAN
                      SECTION  A-A
                   DITCH INLET  STRUCTURE



                        FIGURE 28



                          213

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                       DITCH INLET STRUCTURE
                         WITH CATCH BASIN

                            FIGURE 29
treatments that can include trash, racks, catch basins and/or the grat-

ing inlet structure.  Intake protection should also be evaluated in

the light of the anticipated ditch and culvert maintenance program and

the companion treatment that may be accorded the culvert outlet.  In a

series of several culverts outletting a ditch, varying degrees of treat-

ment to intakes might be considered so that at least one or more of the

culverts would function under very adverse circumstances.


                                  214

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     The minimum cover depth for a culvert should be determined on the




basis of manufacturer's recommendations, appropriate vertical position




of culvert relative to ditch bottom and ditch full flow line (I'd minimum




below subgrade), nature of backfill and kind of backfill equipment,




anticipated haul truck and other logging equipment loads, and construc-




tion equipment loads.  An inactive culvert (crushed) can cause roadway




wash-out, erosion and sediment.




     "The frequency, location and installation method of ditch drainage




culverts is much more important than capacity or size.  However,  minimum




sizes of 15 inch or 18 inch diameter is the accepted practice, depending




on the rainfall intensity	(runnoff and area intercepted)	 and the




influence of ditch debris" (11).




     Ditch outlet culverts should be designed so that the half full




velocities are 2.5 to 3.0 feet per second in order to transport sediment




through the culvert.  If the ditch becomes over silted and the catch




basin or other intake device fails to function, the sediment should pass




through the roadway culvert to an outlet or other necessary downstream




sediment collectors.  Cleaning culverts is a difficult, expensive,




neglected, ignored and often imperfect procedure.  Provision for necessary




sediment collection before or at the culvert intake and/or at or after the




culvert outlet is recommended.  Culvert outlet treatments are discussed




later in this chapter.




     Common culvert materials are corrugated galvanized steel and cor-




rugated aluminum.  When culverts are on steep slopes where design flow




velocities are 10 feet per second and greater, paved inverts are desir-




able to reduce barrel wear resulting from sediment scour.  The type of
                                  215

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coupling band necessary for an installation and whether or not the use



of gaskets is appropriate should be related to the anticipated differential



settlement that might occur along the length of the culvert.  Culvert



separation under a roadway has great potential for causing roadway fail-



ure and subsequent sediment transport.




     Culverts used to transport streams under roadway embankments can



be round, structural pipe arch or structural plate arch.   The latter two



are preferred.  The structural pipe arch enables the wide flat bottom to



be buried in the stream bed.  The structural plate arch has no bottom,



so the stream can remain virtually untouched if care is exercised during



its installation.  (A further discussion of stream crossings follows this



section.)




     Ideally, outfall ends of culverts under roadways should terminate



beyond the toe of the fill.  When the fill is shallow,  this condition



may be satisfied by simply extending the pipe as a cantilever beyond



the fill slope a sufficient distance to clear the toe of the fill.  On



deep embankments, where the outlet point is a considerable distance above



natural ground, a culvert extension anchored to the fill slope may be



required.  Half round culvert extensions are also employed for this



purpose.  Whether the half round will be satisfactory depends on its



anchorage, the quantity and velocity of discharge, and the length




and steepness of the embankment.  Where discharge and flow velocities



are high, splash from half round sections can spill onto the slope,




possibly cause slope erosion and sometimes failure of the anchors.



     Canvas or "elephant trunk" culvert extensions have also been



employed.  They have been subject to vandalism and to freezing shut






                                  216

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in cold weather.  Placing riprap on the fill slope below the culvert

outlet will aid in preventing slope wash.

     The problem of protecting the fill slope at the culvert outlet

point can be minimized by placing the culvert entirely on or within

natural ground.  Determining whether to adopt this alternate is a

matter of evaluating the circumstances at the culvert location in

question.


Sizing Culverts


     The complete hydraulic design procedure for all culverts requires:

     1.  Determination of the design flow - See discussion below and the

         paragraphs on stream crossings and hydrology.

     2.  Selection of the culvert size.

     3.  Determination of the outlet velocity.

             "The many hydraulic design procedures available for
         determining the required size of a culvert vary from empiri-
         cal formulas to a comprehensive mathematical analysis.  Most
         empirical formulas, while easy to use, do not lend themselves
         to proper evaluation of all the factors that affect the flow
         of water through a culvert.  The mathematical solution, while
         giving precise results, is time consuming.  A systematic and
         simple design procedure for the proper selection of a culvert
         size is provided by Hydraulic Engineering Circular No. 5,
         Hydraulic Charts for the Selection of Highway Culverts and
         No. 10, Capacity Charts for the Hydraulic Design of Highway
         Culverts, developed by the Bureau of Public Roads." (Federal
         Highway Administration.) (88,89)

This method is based on the results of both laboratory experiment and

prototype tests.  The method is believed to provide a more rational

approach than older procedures for determining culvert capacity.

     "The procedure for selecting a culvert is to determine the head

water depth from the charts for both assumed inlet and outlet controls.
                                  217

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The solution which yields the higher head water depth indicates the




governing control" (89).  However, the minimum velocity must be 2.5 to



3.0 feet per second at half capacity for transporting sediment through



the culvert.  The procedure stated above includes a determination of the



outlet velocity.  Knowledge of this velocity is pertinent to the evalua-



tion of the potential for erosion at the outlet point of the culvert.



     The sizing procedure, outlined above,  may be augmented by the follow-



ing considerations:




     1.  Arbitrarily reduce roadway culvert spacing below the spacing




         required by mathematical calculation,  to recognize the potential



         for debris and sediment blocking of culvert intakes and/or the



         circumstances at the outlet end.  Large volume high velocity



         discharge may be difficult to control  regardless of the sophis-



         tication of the treatment.




     2.  Arbitrarily increase roadway culvert sizes and/or reduce culvert



         spacing in recognition of the level of accuracy of data used  in



         determining the design flow.



     3.  In a run of three or four cross roadway culverts,  make one a



         size or two larger than calculations require as an "insurance"



         mechanism in case one or more culverts become plugged.



     4.  Be realistic in forecasting or assuming the level of ditch



         and culvert maintenance.




     5.  Size culverts at the low point of  sag  vertical curves for twice



         the calculated flow or alternately size all culverts upstream



         from the low point for 20 percent  more than the calculated flow.



         Provide an inlet structure for the culvert at the vertical curve
                                  218

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     low point.  Make liberal use of trash racks or inlet structures



     for the culverts along the adjacent negative grades.



 6.  Evaluate the potential for subsurface flow interception by the



     road excavation and the possibility that this flow will substan-



     tially increase peak flow to a culvert.



 7.  Since live stream culverts are preferably installed parallel to



     stream gradient with invert buried in the stream bed,  recognize



     this circumstance in flow capacity evaluation.



 8.  Evaluate stream culvert calculated size relative to potential



     stream bed constriction.  Pipe arch or plate arch culverts have



     advantages as previously described.



 9.  Evaluate the potential for manufactured debris upstream from



     stream culverts in terms of the land management program for the



     drainage area.  If the area is to be logged, provisions must be



     made to keep manufactured debris out of the stream or  the culvert



     must be sized accordingly.  The former is the better procedure,



     the latter is guess work.



10.  For a stream crossing ascertain the performance record of any



     existing culverts on the stream above and below the point under



     consideration.



11.  From the reconnaissance information, recognize the potential for



     natural stream bed erosion during storms.



12.  Recognize any effects land management's activities may have on



     water yield to ditches and their associated culverts.
                             219

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Design Aspects of Culvert Installation






     Culvert design usually includes features of the installation that




are important to the performance of the culvert in accordance with design




expectations.  These features, when appropriately specified by the




designer and accomplished by the installer, are germane to the sediment




creation potential occasioned by culvert failure.






     Roadway Culverts.  It is usual to specify that the trench width




shall be limited (pipe diameter plus a distance) and that the trench




walls be vertical for a height at least equal to the pipe diameter and




preferably more.  These limitations are used because wider trenches tend




to increase load on the pipe and require more excavation and backfill.




Reasonable care in installation is assumed for all design criteria or




design tables developed for determining necessary pipe gage.  Handling




the minimum amount of soil when installing a culvert is also advantageous




with respect to the potential for sediment creation.  Culverts may be




crowned when installed to provide for the deflection anticipated by em-




bankment consolidation.



     Culvert trenches are often over excavated and backfilled with select




material (pea gravel is popular) in order to obtain proper pipe bedding




in lieu of shaping the trench bottom for the pipe barrel, or because of




unsuitable foundation material.  The select backfill is usually placed




at least to the spring line (mid height) of the pipe.  If a situation




existed where water was being forced along the outside of a culvert,




the presence of pea gravel backfill would tend to allow this passage as




opposed to the circumstances of pressure build up and possible culvert
                                220

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blow out.  Thus the use of pea gravel backfill for reasons of structural



integrity of the culvert could also have the accompanying advantage of



minimizing sediment potential.  The Ditch Grating Inlet Structure



(Figures 28 and 29) will act to reduce the opportunity for water to pass



along the outside of the culvert.






     Stream Culverts.  The advantages of using structural plate or pipe



arch culverts as a means of minimizing stream bed disturbance have been



previously mentioned.  As with roadway culverts, all of the installation



procedures important to the structural integrity of the installed culvert



(foundation, backfill quality and method) may have bearing on the poten-



tial for creating sediment.



     Upstream fill slopes will usually require erosion protection by the



use of concrete headwalls, rock riprap or gabions. (See Figure 30)  A



conservative estimate of the height and width of the fill slope adjacent



to the culvert requiring this protection is suggested.




     In some circumstances,  an additional safety factor can be included



by provision for an overflow channel across the roadway adjacent to the



culvert.  The roadway profile might be adjusted to form an adjacent low



spot or sag with companion fill slope armoring within the planned over-



flow channel.  Although some sediment creation and transport may occur,



the amount will be much less than that created by a culvert "blow out".



     Clearing of the approach channel of natural debris for some dis-



tance upstream from the culvert is strongly recommended.   The amount of



clearing necessary depends on the individual circumstances at the site,



100 feet upstream is offered as a guideline.   Clearing of the approach



channel should be at least an annual accomplishment.
                                 221

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                                    wate
               Cu/vert
UPSTREAM EMBANKMENT FACE TREATMENT




          FIGURE 30
               222

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WATER COURSE CROSSINGS






     One of the important forest road design problems is the live stream




crossing.  Sudden earth slides and minor roadway surface disintegration




are capable of disabling a road but the potential for road loss and sedi-




ment creation and transport from a washout due to a plugged culvert or




extraordinary high water at a stream crossing is probably greater.  It is




therefore extremely important to exercise the utmost care in the planning,




design and construction of water course crossings.  Robert W. Larse




observed that:  "Surveys of road damage and erosion resulting from high




stream flows indicates floatable debris to be a major contributing factor,




and causing severe road embankment, stream bank erosion or channel




changes" (5).




     Design criteria for minimizing the sediment potential from stream




crossings is interrelated with other design factors whose application is




necessary to satisfy the functional requirements of the site.  If these




criteria are not satisfied, the crossing will not provide satisfactory




service to the land manager.  Therefore the following discussion of




criteria is necessarily broader than the topic of sediment minimization.




The discusion is not, however, a complete treatment of the design




spectrum for stream crossings.






Genera I






     Each stream crossing must receive individual study to determine the




best crossing method.  Sufficient site data must be available so that




the responsible designer can accomplish this individual study.   This data




will be a part of the findings of the reconnaissance phase supplemented






                                  223

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by appropriate topographic, foundation, fisheries considerations and




other information that will define the ambient site circumstances in




adequate detail for design purposes.  A site visit by the project de-




signer is strongly recommended.




     The responsible design professional must know the use and purpose




of the road of which the stream crossing is a part.  The intended road




use may relate to the designer's options in selecting a crossing method.




His task is to meld the use requirements to the site requirements in a




manner that will produce a satisfactory result.






Sediment Features of Stream Crossing Design






     The following aspects of stream crossing design have particular




relevance to the potential for sediment creation.




     1.  Hydraulic capacity of opening.




     2.  Allowances for debris.




     3.  Bank protection (stream or roadway slopes) adjacent to or




         within the crossing area.




     4.  Effect of channel changes or relocation.




     5.  Amount of excavation of foundation work needed within wetted




         perimeter of stream.




     6.  Type of streambed material.




     7.  Timing of construction relative to high water.




     Based on the quality of information available to him, and his com-




petence, the designer can recognize and treat the first six items listed




above in his design solution.   The seventh item involves those who pro-




gram the actual construction as well as the type of design.  Appropriate






                                  224

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communication on this subject is mandatory.




     Sufficient topographic field data for the designer to determine the




hydraulic characteristics of the stream channel is basic to an analysis




of hydraulic capacity.  This data is needed for several hundred feet up-




stream and downstream from the crossing point in order to determine the




water surface level relative to stream banks for various design flows.




Even with an adequate channel section at the crossing, an inadequate




section upstream could cause channel banks to overflow, resulting in




erosion of approach embankments.  This situation may indicate a need to




consider embankment protection riprap, overflow culverts in approach




embankments, overflow approach spans for bridges, or provision for flood




waters to overtop approach embankments.




     Determination of design flows for mountain streams and rivers is




more difficult due to the lack of stream gaging stations and rainfall




intensity records in high altitude areas.  Further,  some researchers




believe that there are no appropriate models available for the predic-




tion of mountain stream flows.




     A nationwide series of water-supply papers entitled "Magnitude and




Frequency of Floods in the United States" has been prepared by the United




States Geological Survey.  Calculations of design flows by the USGS method




or other approach should be cross checked by the following:




     1.  Known flood history of the area.




     2.  Performance of crossings of similar streams.




     3.  All available gaging records of this and comparable streams.




     4.  Field data indicating high water marks, natural overflow




         channels, old stream beds, etc.
                                 225

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     Any proposed changes to natural channels or the inclusion of flood




way obstructions should be evaluated to determine the changes that might




occur in the hydraulic behavior of the stream.   Channel relocations,




when constructed in the dry, are not necessarily detrimental to the




stream.  Easing or elimination of sharp bends may remove a constriction




to hydraulic capacity.  (Stream bed scour may also increase.)  The rule




is to make a total evaluation of the proposed design including water




quality and fisheries considerations.  The U.S.  Bureau of Public Roads




(Federal Highway Administration) Hydraulics of Bridge Waterways is a




good reference for the analysis of stream obstructions (i.e. bridge




piers) for streams or rivers (90).




     Table 13 gives scour velocities for certain kinds of ditch soils.




Values shown in this table provide an indication as to the maximum




velocities that can be tolerated in channels without using riprap




treatments of rock or gabions.  The U.S. Bureau of Public Roads Design




Chart for Open Channel Flow includes data for grassed channels.  Design




charts include a procedure for determining maximum permissible velocities




without channel scour (91).



     Important to the satisfactory performance of riprap lined channels




is the sizing of the riprap and the companion channel side slope.  The




Bureau of Public Roads Design of Roadside Drainage Channels 1965 includes




procedures for evaluating the adequacy of channel linings relative to




channel slope and flow velocity.  This publication recommends that "if




the mean velocity at the design flow exceeds the permissible velocity




for the particular soil type, the channel should be protected from




erosion" (92).  Design procedures using various linings are discussed.






                                  226

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     Riprap bank protections should extend a minimum of two feet "below




the stream bed.  This is to prevent erosion of the bank material and sub-




sequent displacement of the riprap.






Stream Crossing Methods






     There are three stream crossing methods employed on forest roads,




fords, culverts and bridges.  Factors influencing the selection of the




appropriate crossing method include stream size, debris potential, ver-




tical position or road relative to stream, foundation conditions, con-




struction cost and maintenance cost, and contemplated road use and life.






     Fords.  Fords are an attractive alternate for secondary or spur




road crossings of small drainages particularly if road use is limited to




the dry season when no flowing water is in the channel.  Ford installa-




tion requires minimal disturbance to the stream channel.  Problems




attendant to bridge or culvert installation such as size of opening,




provision for debris passage and channel or embankment riprap are




largely avoided.




     Gabions for ford crossings have been successfully used in the Modoc




National Forest.  Allen J. Leydecker in an article entitled "Use of




Gabions for Low Water Crossings on Primitive or Secondary Forest Roads"




(93) describes the design use.  A typical installation cost $3,000 in




1971 and was accomplished on a force account basis.  The installation




consists of gabions placed at the roadway grade backfilled by stream




gravel to form the road surface.  "In about a year's time, fines trans-




ported by the stream cement the gravel backfill and construction scars




heal,  leaving a satisfactory stream crossing ..."  Figure 31 is a
                                  227

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    reproduction from Leydecker's paper portraying a section through the

    ford.   The  ford was not damaged during the following winter when peak

    flows were  estimated by Leydecker to have been approximately 400 cfs.

 ti^nsn^n
Source:
                           GABION FORD
                           FIGURE 31

Leydecker, Allen D.,   "Use of Gabions  for Low Water Crossings on
Primitive or Secondary Forest Roads"
        Culverts.  Culverts have been regarded by many designers as the

    economic  solution for small stream highway crossings during the past

    twenty-five years.  They have largely displaced the previously used

    short  span bridge for reasons of economy and the goal of maintaining an

    uninterrupted roadway and shoulder width.  The performance of culverts

    on  forest roads suggests that  the determination of use should not be

    as  quickly assumed as has been the case for county roads, city street?
                                     228

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and state highways.  The site circumstances that may be different from




those of a typical public highway installation are steepness of terrain,




potential for debris, ability of steep terrain to retain fills adjacent




to the culvert and difficulty in compacting fills with equipment usually




used in forest road construction.  Reliability of the calculation for




required culvert capacity is another factor.




     The foregoing discussion is particularly directed toward the round




culvert.  No specific guidelines or "rules of thumb" are available to




assist the designer in making a choice between bridge or culvert.  Atten-




tion to the individual circumstances of the site by a competent pro-




fessional is the only known rule.




     Other features of culvert design are discussed under that subject




heading.






     Bridges.   Forest road bridges have been designed using a variety




of structural materials for substructure and superstructure.  The selec-




tion of a bridge type for a particular site is dependent upon the func-




tional requirements of the site, economics of construction at that site,




live load requirements, foundation conditions, policies or opinions of




the owner, maintenance evaluations and preferences of the project designer.




The type of design selected can have a bearing on the potential for sedi-




ment creation.




     The bridge design can go awry if insufficient attention is accorded




the site circumstances.  A quick conclusion that the site permits the




use of an accomplished design from a "similar" site should be avoided.




     Location of bridge foundations relative to the normal stream channel




and forecasted flood channel can be an important element.  While it is
                                  229

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not suggested that all bridges must span flood channels,  an evaluation



of the effect on the channel with an obstruction therein is necessary.



Channel obstructions can cause channel scour and contribute to debris



blockage.




     Although there are different views on the minimum desirable hori-



zontal and vertical stream clearances in streams not subject to naviga-



tion, some arbitrary rules based on judgment and experience in the area



should be established.  Vertical clearances should not be less than 5



feet above the 50 year flood level plus .02 of the horizontal distance



between piers.  Horizontal clearance, between piers or supports in



forested lands or crossings below forested lands, should not be less



than 85 percent of the anticipated tree height in the forested lands or



the lateral width of the 50 year flood.



     In considering a longer span bridge,  there are economic tradeoffs,



higher superstructure cost versus possible reduction in foundation cost




as compared to a short span.  Subaqueous foundations are expensive and



involve a degree of risk attendant to the operations of cofferdam con-



struction, seal placement and cofferdam dewatering.  In addition to the



water quality degradation that can occur with a lost cofferdam, the time



and money loss will be significant.  Subaqueous foundations often limit



the season of construction relative to water level and relative to fish



spawning activities.  Thus, construction timing has to be rigidly con-




trolled.



     Type of foundation support also deserves consideration from a sedi-




ment perspective.  If deep excavations are necessary to reach suitable



strata for direct bearing footings, pile supports may result in less
                                  230

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disturbance of the ground in and around the stream thereby reducing the




amount of excavation, shoring and backfilling.   A careful review of the




economic tradeoffs is appropriate rather than an immediate conclusion




that direct bearing footings are correct because the support strata is




present at some depth.




     The remoteness of many forest road bridge sites suggests the maximum




use of precast or prefabricated superstructure units for economic reasons.




The use may be limited by the capability to transport the units over




narrow, high curvature roads to the site, or the horizontal geometry of




the bridge itself.  Precast or prefabricated superstructure units avoid




a requirement to falsework the stream as is required for a cast-in-place




concrete bridge.  A cast-in-place structure may place limits on the




construction season since the falsework may block the stream and is




very vulnerable to debris damage.  Any delays of construction (changed




foundation conditions) that result in falsework being placed later in




the season than initially anticipated can be hazardous.   Some streams




are subject to flash floods even in the "dry" season.




     The U.S. Forest Service is constructing nine steel  girder bridges




on Forest Development Roads in the South Tongass National Forest, Prince




of Wales Island, Alaska.  Short construction season and  the remote sites




(no local source of concrete aggregates) influenced the  designer's de-




cision to maximize use of prefabricated steel elements for both super-




structure and substructure units.




     The abutments for three of the bridges are U-shaped made entirely




of steel sheet piling.  The structures clear span the normal water level,




end supports interfere slightly with estimated high water.  Although
                                 231

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minimizing sediment potential may not have been a stated design goal,



the abutment design is one that clearly accomplishes this.  Placing the



sheet pile abutments requires minimum handling of natural soils as com-



pared to an abutment designed in reinforced concrete.



     A conservative vertical clearance for debris at high water was also



provided.  A lateral bracing system was provided in the plane of the



lower girder flanges because of vulnerability to drift and debris during



high water (94-).






CULVERT  OUTLET TREATMENTS






     The last opportunity to control or inhibit the movement of sediment



in the roadway drainage system is at or near the culvert outlet point.



The action of the water at the outlet point can also create sediment if



the flow velocity is of a magnitude that will scour the natural soils



at the outlet.



     Due to the many variables involved, all possible solutions to this



problem are not included in the following discussion.  A few practical



solutions that can be adapted as the designer may determine are outlined.



     If appropriate upstream measures have been taken for sediment con-



trol, the degree of treatment at the culvert outlet may be minimal.



Appropriate upstream measures may include:




     1.  Adequately designed and constructed ditches with appropriate



         linings.



     2.  A Ditch Inlet Structure with Catch Basin that functions properly



         to trap sediment.  Sediment that is not deposited in the ditch



         and bypasses the catch basin is considered as flowing through






                                  232

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         the roadway culvert to its outlet.  Whether or not storm waters




         are likely to contain significant sediment at the culvert out-




         let depends upon the eroditdlity of soils over which these




         waters have passed and the volume and velocity of flow.




     Figures 32 and 33 show two roadway culvert outlet conditions.  The




culverts shown in Figure 32 outlet at least 150 feet from a live stream.




For this condition a short length of lined culvert apron at the outlet




point to act as an energy dissipator and a scour inhibitor has merit.




The lining can be rock rubble, ten feet minimum in length with a width




equal to twice the culvert diameter as shown in Figure 34.




     If the remaining distance to the live stream is relatively flat and




contains vegetation, channel flow velocity will tend to decrease.  Remain-




ing sediment will tend to deposit in the vegetation.  However, if the




remaining distance to the stream is steep and bare, additional energy




dissipation may be necessary in order to permit sediment deposit.  The




rock apron can be continued further beyond the culvert outlet and a rock




dike with height equal to the culvert diameter and width equal to twice




the culvert diameter installed in the outlet channel as shown in Figure




35.  In addition, a further measure might be the placing of slash from




the roadway clearing to act as a sediment barrier.




     Figure 33 shows a roadway culvert outlet in close proximity to a




live stream.  In this case, placing the outlet end of the culvert in a




rock lined channel whose minimum depth is at least twice the culvert




diameter as shown in Figure 36 may be appropriate.  If the culvert exit




velocity is 10 feet per second or greater, a rock dike as shown in




Figure 35 to act as an energy dissipator may be necessary in order to
                                  233

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                       At least '50
SHALLOW FILL-SHALLOW CULVERT
   HIGH FILL-SHALLOW CULVERT
           CULVERT OUTLETS




             FIGURE 32

-------
j t
                                            //heat
        CULVERT OUTLET NEAR STREAM




               FIGURE 33
           PIPE CHANNEL DETAIL




                FIGURE 34




                  235

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             PLAN
          ROCK DIKE




          FIGURE 35
ALTERNATE PIPE CHANNEL DETAIL




          FIGURE 36




            236

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insure sediment deposit before storm waters intersect the stream.




     If suitable rock is not available for a channel lining, an alter-




nate might be the use of clearing slash to construct gravel filled crib




wall channel linings as shown in Figure 37.  Gabions and sacked riprap




can also be used but they are costly.  The use of slash has the secondary




advantage of providing a disposal method for some of the clearing debris.




     An outlet treatment for a large culvert with high storm water flows




is shown in Figure 3$, an Energy Dissipating Silo.




     Even with the upstream sediment control features of catch basins




and rock lined ditches, there may be a period when excessive sediment




can be transported.  This will happen during construction and for a




time thereafter until new vegetation and soils stabilization measures




become effective.  Figure 39 shows a roadway culvert (or combination of




culvert discharges, e.g. collector ditch at toe of slope) discharging




into a sediment pond (basin).




     The velocity of flow through the sediment pond should be approxi-




mately one foot per second and preferably less in order for settling to




take place.  Settling velocities of sand and silt in still water are




shown in Table 15.  The tabulation in this table suggests that the sedi-




ment pond should be large enough to retain the maximum flow input for




at least one hour if the pond is designed for a two foot water depth in




order to settle silt sized sediment.




     The designer will have to determine the actual pond size, dependent




upon topography,  soils, porosity, water quality requirements,  etc.  After
                                    237

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       PLAN
                       AH to** &"
                                     0
   SECTION  A A

GRAVEL FILLED CRIB WALL
     FIGURE 37
       238

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         rook
                       ENERGY DISSIPATING SILO

                              FIGURE 38
                  *  -/
                  &oaam/ay
Note:   Sediment pond not necessarily located
       immediately adjacent to the roadway prism.
                     CULVERT OUTLET TO SEDIMENT POND

                               FIGURE 39
                                 239

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                                TABLE 15

              SETTLING VELOCITIES FOR VARIOUS PARTICLE SIZES
                         (10.00 mm to 0.00001 mm)
    Diameter
       of
    Particle
Order
 of
Size
Settling
Velocity
Time required
  to settle
  one foot
       mm.
                mm./sec.
10.0
1.0
0.8
0.6
0.5
0.4
0.3
0.2
0.15
0.10
0.08
0.06
0.05
0.04
0.03
0.02
0.015
0.010
0.008
0.006
0.005
0.004
0.003
0.002
0.0015
0.001
0.0001
0.00001
Gravel 1,000
100
83
63
Coarse Sand 53
42
32
21
15
8
6
3.8
Fine Sand 2.9
2.1
1.3
0.62
0.35
0.154
0.098
0.065
Silt 0.0385
0.0247
0.0138
0.0062
0.0035
Bacteria 0.00154
Clay Particles 0.0000154
Colloidal Particles 0.000000154
0.3 seconds
3.0 seconds







38.0 seconds







33.0 minutes







55.0 hours
230.0 days
63.0 years
i/The Water Encyclopedia by David Keith Todd,  1970 (Page 86)
  Water Information Center, Port Washington,  N.Y.
                                   240

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 a period  of use,  the  fines  will  tend  to  seal  the pond.  After  the road




 project is  completed  and upstream erosion  control measures become effec-




 tive,  the performance of the  pond may be less important.  It should be




 recognized  that the circumstance of terrain and road  corridor may be




 such  as to  preclude the  use of a sediment  pond in many  situations.






 HYDROLOGY




      Preceding parts  of  this  discussion  on drainage design have pointed




 out the importance of the determination  of the design flow to the success-




 ful performance of a  drainage system.  The designer is  interested in deter-




 mining whether logging and  road  building in the forest, and forest location




 will have a significant  effect on the flow volumes he should provide for,




 with respect to road  drainage and stream crossings.






 Logging and Roadbuilding






     Rothacher reports that an increase  in annual stream flow in the




 Pacific Northwest may be expected after  clearcutting.  He also points to




 an increase in early  Fall seasonal flows after  clearcutting because the




 soil moisture content  is higher  in a  clearcut area as compared to the




 soil moisture content under old-growth forest.  Thus less of the Fall




precipitation is needed to recharge storage within the soil.   Rothacher




does not believe that  clearcutting significantly changes peak flood flows




in areas west of the Cascades.  Flood flows normally occur after the soil




is saturated, "wet mantle" condition,  and are directly related to the




amount of precipitation.   Rothacher points to some contrary evidence on




small drainages containing roads as well as having been  clearcut (95).







                                  241

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     R. Dennis Harr and others believe that it is unlikely that there

will be culvert and bridge damage in Oregon Coast drainages as a result

of  clearcutting, provided designs are made on a 25 year storm frequency

basis.  They believe that the effect on roads in small drainages can be

more serious as roads are permanent and will exist during large storms:

     "Success or failure of a certain size culvert or bridge might
     depend heavily on the amount of roads that eventually will be
     built in the watershed whose outlet stream is to be contained
     within a culvert or bridge" (96).

     Bethlahmy is convinced that  clearcutting a small drainage will

result in greater peak/flows in that drainage.  He believes that culvert

capacities and bridge clearances in these drainages should be designed

to accommodate conditions after logging (97,98).

     Rothacher and Glazebrook believe that the Pacific Northwest storms

of December 1964 and January 1965 were very unusual.  They predict that

storms similar to these can be expected in the Cascade and Coast Ranges

at least once in 50 to 100 years.  They also observe that localized

storms of these intensities can occur more often:  therefore, "our plans

and actions must give them adequate consideration" (11).  The authors

state  that flood probabilities and forecasting have been evolved mainly

for the requirements of downstream communities and that "much of the

information currently in use has not been verified for mountainous areas."

     These articles suggest that a conservative approach to the calcula-

tion of the design flow for a stream crossing be employed especially if

precipitation data for the immediate area is not available.  Other con-

siderations involved in determining the appropriate opening size for bridge

or culvert are discussed in the previous parts on Culverts and Stream

Crossings.

                                    242

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Subsurface Water Considerations


     Another consideration is the potential for roadway cuts to intercept

ground water flows thereby converting this flow to overland flow into

ditches of a roadway drainage system.  Attention was invited to this

phenomena in the route reconnaissance discussion with respect to field

reconnaissance.  Megahan's studies in the Pine Creek drainage, a tribu-

tary of the Middle Fork of the Payette River, Idaho, showed that the

quantity of water whose source was intercepted ground water flow was

many times greater than the quantity whose source was overland flow.

     "Interception of subsurface flow is one of the more insidious
     effects of road construction because its occurrence often is not
     readily apparent.  Subsurface flows occur only during large rains
     and/or snowmelt when large volumes of water are supplied to the
     soil.  Such flows begin, reach a peak, and recede within a short
     period.  Many times, the climatic event that generates subsurface
     flows also limits access, making it impossible to see flows as
     they occur.  This is particularly true during snowmelt and rain-
     on-snow events in the mountains.  As soon as subsurface flow
     ceases, most exposed roadcuts dry out completely and little evi-
     dence of flow remains.  Another factor leading to the lack of
     recognition of subsurface flow is the fact that flow emergence
     is not limited to drainage bottoms, but may occur on straight or
     even convex side slopes as well" (49).

     Megahan believes that total volume of watershed runoff increases

when subsurface flow is converted to surface flows.  Whether peak flow

rates are increased depends on the simultaneous occurrence of the

normal peak flows from the watershed with the flow from intercepted

subsurface water.  Certainly the local effect on ditches and culverts

at or near subsurface discharge or outlet point could be significant.

     Other effects are related to questions of stability of cut banks,

potential road surface erosion and stability of fills.  Megahan believes

that much of the road erosion reported in the Idaho Batholith "is very
                                  2-43

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likely a direct result of subsurface flow interception."





Forest Location






     There is little question that total precipitation amounts increase



with elevation, except in areas of pronounced rain shadow effects.  How-



ever, considerable controversy appears to exist as to the effects of



elevation on rainfall intensity.  Dorroh's (99) evaluation of rainfall



data from the southwestern United States indicated that, although both



total precipitation and thunderstorm frequency tend to increase with



elevation, the heaviest individual rains occur in the valleys.  Croft



and Marston (100), however, stated that higher rainfall intensities



could be expected on the windward slopes of the Wasatch Mountains in



Utah than in the adjacent valleys.  In the very different climate of



coastal British Columbia, precipitation at higher elevations is apparent-



ly characterized not so much by higher intensities as by longer duration




at a given rate (101).



     Schermerhorn (102) studied the effects of various parameters, most



notably elevation, upon annual rainfall amounts in western Oregon and



Washington, where extremes of 20 inches to 150 inches of average annual



precipitation occur.  His work revealed very little relation between



station elevation and annual rainfall, but that most of the variation in



average annual precipitation for the 280 stations studied could be




accounted for by relatively simple indexes linked to broad scale topo-



graphic and latitude factors.  Three main index parameters were defined:



index elevation, barrier elevation, and index latitude.  Use of a graphi-



cal relationship involving these three main parameters to calculate
                                  244

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annual precipitation for the 280 stations yielded an unadjusted standard




error of estimate of 7.2 inches for an average precipitation of 63 inches.




Schermerhorn did not make any attempt to use his method to develop eleva-




tion-rainfall intensity relationships, a key parameter for determining




peak design flows.




     Cooper (103) reported on an extensive study of elevation-precipita-




tion relationships within a 93 square mile area in southwestern Idaho




where continuous rainfall recorders had been installed at an average




density of one per square mile and operated for four years.  The area




had an elevation range of 3,500 feet and climatic variations resulting




mostly from elevation and topographic features rather than from regional




air mass differences.  The rainfall data indicated that average annual




precipitations increased about 4 inches for each 1,000 feet increase in




elevation and ranged from 8 inches in the lower part of the valley to




28 inches at the higher elevation.  Numerous methods of data analyses




that attempt to establish other rainfall-elevation relationships indicate




no relationship between elevation and peak rainfall intensity and eleva-




tion and several other intensity-related parameters.  The only relation-




ship that could be established was that the logarithm of the proportion




of rainfall exceeding a given intensity plotted as a straight line




against intensity.  There was no difference in this relationship when




the data were separated by elevation classes.   Cooper noted that this




relationship is rather universal and holds true for many other parts of




the world as well.




     Cooper concluded that the apparent lack of relationship between




rainfall intensity and elevation suggests that data from accessible
                                  245

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valley stations can be used to estimate the relative occurrence of




high intensity rains throughout an area of appreciable range in eleva-




tion.  At least under the conditions encountered in southwestern Idaho,




about the same proportion of the seasonal rainfall exceeds a given in-




tensity at high elevations as at low ones.  Because there tends to be




more total rain at high elevations, there is likewise more intense rain




at mountain stations than in the valleys, but the relative proportions




remain nearly constant.




     Others believe that much is unknown about rainfall intensities at




the higher altitudes and question the applicability of the currently




available models.  As was previously stated in the discussion on stream




crossings, the engineer must cross check his calculated design flows




obtained from the USGS or other method.






                   CONSTRUCTION SPECIFICATIONS






     An essential part of the design for any road project are the com-




panion specifications.  Preparation of these specifications must not be




separate or removed from the supervision of the forest or civil engineer




who is preparing the road design.




     A serious mistake is made in those cases where separate personnel




are authorized to prepare the specifications for design plans prepared




by others.  This inadequacy is frequently represented by notation on the




plans such as "see specifications for detailed requirements", "see speci-




fications for procedures", "see specifications for further requirements".




Such notations frequently mean the designer has not made up his mind as




to what the requirements or procedures should be.  Definable accomplish-






                                  246

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ment cannot be attained without positive and non-contradictable plans




and specifications.  The foregoing is a very brief analysis of the




relation between plans and specifications and is placed herein to em-




phasize the need of the utmost correlation between the two companion




documents.






STANDARD  SPECIFICATIONS






     Many  design organizations have prepared volumes or multicopies of




specifications particularly oriented to their endeavor.  The volumes




have such  titles as Standard Specifications for Road and Bridge Construc-




tion and set forth general, legal, and specific engineering requirements




under which the proposed construction is undertaken as a mutual agree-




ment between the owner and the contractor.  These standards are revised




from time  to time and vary between regions because of different regional




circumstances.  The U.S. Department of Agriculture has prepared such a




volume entitled "Forest Service Standard Specifications for Construction




of Roads and Bridges."




     A further group of specifications published at regional,  national




and international levels is devoted primarily to materials and methods




of testing materials.  Prominent and valuable organizations in this




group are The American Society of Testing Materials,  The American Stan-




dards Association,  and The American Association of State Highway Officials.




Frequently specifications from one or more of this group are included




by reference, or quotation in the specifications published or  adopted




by the owner or agency.
                                 247

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SPECIAL PROVISIONS






     To define and describe the individual items of work,  local circum-




stances, special construction items (those not included in the Standard




Specifications), times of accomplishment,  legal requirements,  and pay-




ment conditions, a further document is written for each project entitled




Special Provisions.  This is part of the contract documents.   The Stan-




dard Specifications and the Special Provisions combine to  form the




Construction Specifications.  Items specifically related to sediment




control will usually be a part of the Special Provisions.




     The Special Provisions should include a separate paragraph stipula-




ting that the successful bidder shall prepare and submit within 30 days




a detailed schedule of on site construction starts, material purchases




and phase accomplishments.  The schedule can be of assistance in evalua-




ting whether the contractor recognizes construction elements and se-




quences relating to sediment control as envisioned by the  designers.




It can also point out potential problem circumstances during construction




due to the forecasted timing of certain operations relative to seasons.




     A common practice in special provision writing has been to lump




together certain "nuisance" items, including requirements  for water qua-




lity control within the work site.  Elaborate descriptions are often




written about the Contractor's obligations, all of which are to be en-




forced at the sole discretion of the Engineer and for which compensation




is to be considered as "incidental to the other items of work involved




in the project".  Such procedures are of little practical help to a




Resident Engineer.  While owner's representative and Contractor feud




over whether the particular issue is or Is not one of the "incidental"
                                   248

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items, the problem may magnify and its potential for damage to completed

work and resources may increase.

     The Special Provisions should provide compensation for the Contractor

for all labor, materials, tools and equipment he is to furnish including

items involved in temporary or permanent sediment control features.   They

should advise the Contractor as to the manner in which he will be asked

to perform various tasks, whether the demand will be intermittent,  and

whether "extra" or "standby" crews or materials are involved.   The impor-

tance of dealing with changed circumstances swiftly is discussed else-

where in this report.  The Special Provisions should support this goal

by providing means for swift, equitable adjustments in contract compensa-

tion.

     A possible technique is to establish compensation for certain emer-

gency work on a force account basis with an estimated amount included

in the contract documents.  This approach has merit provided the estimated

amount is a realistic assessment of the circumstances that may be encoun-

tered.

     In the Timber Purchaser Road Construction report by USFS, Region 6,

it was found that scheduling techniques are not being used by timber sale

road builders and the Forest Service.

     "Historically timber sale road construction activities have been
     triggered by the timber market demand.  This factor is a basic
     problem in the scheduling difficulty and affects the timing of
     construction starts and construction progress.  There is a general
     lack of documented, or even oral disclosure of construction sched-
     ules.  Some inspectors wasted valuable time by constantly visiting
     project sites just to find out when construction was starting"  (8).

     Obviously, the potential for sediment creation during construction

is related to the season in which certain construction elements are  being
                                  249

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accomplished.  Contract scheduling should provide for construction acti-

vities to be accomplished in their appropriate season.   If the project

is to extend over more than one season,  the procedures  and require-

ments for shutdown at the close of each season should be specified.

The basis for determining when conditions warrant seasonal shutdown

should also be included in the special provisions.

     Larse summarizes the construction activity thus:

     "Although there are many commonly practiced techniques to mini-
     mize erosion during the construction process,  the  most meaningful
     is related more to how well the work is planned,  scheduled and
     controlled by the road builder and those responsible for deter-
     mining that the work satisfies design requirements and land
     management resource objectives" (5).


CONCLUSIONS


     The foregoing discussion was written in terms  of the owner-contractor

relationship.  The intent of the comments is believed applicable in in-

tent to the circumstances of road construction by a timber purchaser  or

road construction by a land owner's own forces.
                                  250

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       CONSTRUCTION TECHNIQUES


     As earlier stated,  Route  Planning and Reconnaissance are regarded

"by many as  the most important  phase of logging haul road development.

In design,  the planning and reconnaissance data are translated by design

into plans  and specifications  to meet all of the road objectives and to

guide the construction phase.   Larse observed as follows:

     "Construction of the designed facility is a challenge to the
     road builder to complete  the work with a minimum of disturbance
     and without damage to or  contamination of the adjacent landscape,
     water  quality, and other  resource values.  Some of the most severe
     soil erosion can be traced to poor construction practices and job
     management, insufficient  attention to drainage during construc-
     tion and operations during adverse weather conditions" (5).

     The Engineer in charge (Resident Engineer) or the inspector is the

last link in the long chain of a total effort to produce a logging haul

road in a manner that will minimize sediment.  Field changes are to be

expected.  The Resident Engineer acting alone, or with the design engi-

neer, must  decide the corrective measures to be taken.  Other than field

changes the inspector must require adherence to the plans and specifica-

tions .

     Manpower may be a limiting factor to supply sufficient inspectors

for the work load in a given region.  However as the work load peaks,

qualified individuals having other duties could be assigned to inspection

activities.

     The Resident Engineer and the inspectors must be relentless in

their effort to fully implement the plans and specifications as envisioned

and designed.  The construction specifications should provide a means

of payment  for many of the processes that the contractor may need to
                                  251

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accomplish and which are of benefit in arresting sedimentation including



those attendant to changed conditions.  These items arise from condi-



tions unforseen by the design engineer such as seasonal variations and



foundation and soils inconsistencies.  The discussion that follows in-



cludes construction features that require individual analysis and the



application of the appropriate construction technique in order to mini-



mize erosion or sediment transport.






                       CLEARING AND GRUBBING






     The Forest Service Standard Specifications for Construction of



Roads and Bridges and the amendments clearly define clearing and grubbing



activities and methods.  Each Region supplements these specifications



with methods peculiar to its area.



     Clearing and grubbing then is the first activity in constructing a



forest road that disturbs the forest floor and surrounding soils.  Flash



storms under these conditions can produce instant erosion and sediment



problems.  This work is a necessary part of the road work.  A precaution



that should be taken to prevent a part of the potential sediment flow



is to not disturb more ground than is absolutely necessary until a satis-



factory drainage system is provided.  The brush collected from the clear-



ing and grubbing operation can be placed at the toe of embankments or



below culverts to act as a filter and retardant to sediment flow.



     Attempts to begin excavation prior to the completion of clearing



have resulted in mixing slash and organic material with earth.  The mixed



material acts as a contributor to the sedimentation problem rather than as
                                  252

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a filter.  It also may have too high an organic content to be used as

fill material thus requiring wasting.

     Merchantable timber from the clearing operation might be tempor-

arily stacked at the toe of a fill until the fill is stabilized.  Small

logs may have use as walls for channel linings as suggested in drainage

design and as shown on Figure 37.

     Clearing and grubbing should be scheduled to proceed just in

advance of earthwork.  Sections which are not going to be graded in the

current season should not be cleared and grubbed.


                             EARTHWORK


     During excavation and embankment activities the total roadway prism

is vulnerable and is subject to erosion and sediment flow from rain

storms of relatively slight intensity.  Larse states:

     "When soil moisture conditions are excessive, earthwork
     operations should be promptly suspended and measures taken
     to weatherproof the partially completed work .  . .  clearing
     debris underlying, supporting or mixed with embankment
     material is a common cause of road failure and mass soil
     movement.  The necessary slope bonding, shear resistance,
     and embankment density for maximum stability cannot be
     achieved unless organic debris is disposed of before em-
     bankment construction is started" (5).

     Road builders on Washington's Olympic Peninsula have found that a

shovel can be worked in much wetter weather than bulldozer.  The shovel

does not tend to disturb the subgrade in marginal weather to the degree

that a bulldozer does.  Shovels on mats are a common soft ground technique

on the Olympic Peninsula and across muskeg in southeastern Alaska.
                                  253

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     Embankment compaction should be accomplished by one or more of the



following types of equipment.



     1.  Tamping rollers.



     2.  Smooth wheelpower rollers.



     3.  Pneumatic-tired rollers.



     4.  Grid roller.



     5.  Vibratory rollers.



     6.  Vibratory compactor.



     7.  Bulldozer.



     In the past, the bulldozer has  frequently been the sole compactor



used on forest roads.  It has proven to be very ineffective when the



dozer blade is so wide that it prevents the tracks from covering the



entire roadbed width.  The dozer may be used provided it can compact from



out to out of the total roadway.  A more satisfactory compaction job will



be obtained by having the dozer do its primary job of moving earth and



using equipment specifically designed for compaction to accomplish the



compaction.



     Embankments should be placed and compacted to the required density



to avoid instability, control drainage flow and deter massive movement.



Embankment placement in layers with attendant compaction is necessary.



Sidecasting, as a construction method has limited value.  The literature



on forest road failures contains many references to failures due to




improperly constructed embankments.



     Waste sites should be as carefully prepared as embankment portions




of the roadway.  Waste material could be used as a portion of the road-



way embankment (as shown in Figure 40) instead of being end hauled an
                                  254

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excessive distance.   The width and number of benches will be determined

by the height of the fill and the quantity and quality of waste material

involved.

     Borrow pits should be closed by dikes or dams to prevent sedimen-

tary flows into adjacent streams or have a sediment pond at the outlet

end.  The dikes or dams should be removed when the borrow pit water

ceases to carry sediment.  Borrowing from running streams should be pro-

hibited.
                                                       B&ichftil
                          ALTERNATE WASTE SITE
                                FIGURE 40
     Ballast may be placed only on shaped  and drained subgrades in a

manner that will not deform,  rut or rupture the  subgrade.
                                  255

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                              DRAINAGE


     No other item is as important to the permanence and usefulness of

the forest road and the control of stream sedimentation as the drainage

system.

     "In many places, careless and improper construction of a high
     mountain logging road can nullify all the effort expended in
     well considered design and location . .  . Poor construction
     and inadequate drainage have triggered land slumps in water-
     shed after watershed and have resulted in the most serious
     form of accelerated erosion that occurs  during timber harvest-
     ing .... Therefore during all phases  of road construction,
     protect water quality by using every possible and applicable
     soil and water conservation measure" (4-2).


DRAINAGE  DURING CONSTRUCTION


     The drainage design discussion indicated that temporary ditches and

other drainage facilities may be necessary during the construction phase.

To achieve the goals of permanence of slopes  and road beds and to mini-

mize sedimentation, the following suggestions have been of consequential

advantage.

     "Protect all fill areas with surface drainage diversion Systems.
     Place culverts so as to cause the minimum possible channel dis-
     turbance and keep fill materials away from culvert inlets and
     outlets .  . .  Allow road machines to work in stream beds only for
     laying culverts or constructing bridge foundations.   Divert stream
     flow from the construction site whenever possible in order to
     prevent or minimize turbidity.  Clear drainage ways of all woody
     debris generated during road construction.  Windrow the clearing
     debris. .  . .  outside the roadway prism (to use as a drainage
     filtering system)" (42).

     The previous paragraph mentioned several antidotes to control con-

struction drainage.  Also the use of visqueen or plastic sheets, tem-

porary flumes,  installation of a second culvert (preferably by jacking),

-------
culvert extensions and settling basins are other techniques.   Roadway




surface dips should be installed as soon as possible so that  they




can be utilized to control storm water while construction continues.




The most important technique, however, is that of observing,  watching




and promptly correcting an installation that does not accomplish its




intended function.




     During the initial construction period, the Resident Engineer must




have all design data, rainfall and stream flow records at hand.  If any




drainage installation does not supply the desired results as  to capacity,




turbidity, or indicates instability in the early stages of construction,




he must have the knowledge and authority to direct the changes that will




give the desired results of stability, capacity and turbidity standards.




Applying for a re-design study, awaiting authorization from higher




echelons and/or additional funds, will serve only to magnify  the adversity.






DRAINAGE  CONSTRUCTION






     A prevalent concept of drainage construction must be abandoned and




a new one evolved.  The prevalent concept that the contractor is permitted




to install various drainage features when he chooses based on available




equipment, subcontractors, accomplishment of like items at one time,




such as placing riprap or headwalls, must be pushed aside for the concept




of doing in order the things that are needed to stabilize slopes and re-




duce to a minimum the transportation of sediment.  Without a  doubt applica-




tion of this new concept will cost more in initial expenditures for the




drainage system than would accrue under the now prevalent procedure.  An
                                  257

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economical comparison between the two would not be realistic unless



values can be assigned to the potential cost of reconstruction of



water damaged road features and the cost of excessive sediment trans-



port.




     The grading of a roadbed should not be extended beyond the con-



struction of the companion and attendant drainage features.  Few slides



should occur on hillsides properly graded and drained, or on slopes



guarded against erosion.  It is recognized that sudden rains can fall



during the construction season.  If the ditches require rock linings,



matting or other protective measures, the actual ditch grading and



shaping should not be too far advanced ahead of the protective treat-



ment.  Always grade, shape and finish ditches from the downstream end



to the upstream end.




     Culverts should be installed as the road work progresses.  The



culvert and its related drainage features, as required, should be in-



stalled in the following order:




     1.   Place debris and slash to be used as a filter system.



     2.   Construct sediment ponds.



     3.   Install energy dissipating devices.



     4.   Place rock rubble rock or matte channel lining.



     5.   Lay the culvert from the downstream end to the upstream end.




     6.   Construct ditch inlet structure with or without catch basin.



     It is important to note from the above that all drainage work



should start at the downstream end and progress to the upstream end.




This installation procedure will enable surface and intercepted sub-
                                  258

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surface waters to flow in a finished channel downstream and away from

the work area.  The system must be kept operative at all times.   If

it is necessary to install a culvert in a live stream,  diverting the

water by parallel channel or pumping around the work area may be

appropriate.

     The reader is reminded of the discussion in drainage design

relative to culvert installation, that the designer assumes reason-

able care in culvert installation.  Critical features are bedding,  back-

filling and pipe joints.  Hartsog and Gonsior's China Glenn analysis

indicates a lack of skill, supervision and appropriate  equipment con-

tributing to difficulties with culvert installations (14).

     All drainage construction activities should be closely super-

vised to insure that the various work items are meshing together at the

scheduled time.  Correct those items lagging behind schedule immediate-

ly.


                      CONSTRUCTION EQUIPMENT


     The U. S. Forest Service Region 6 Road Audit states:

     "The use of improper and oversized equipment by timber pur-
     chasers was identified as a problem area . . . Special equip-
     ment is needed to properly accomplish some construction tasks
     and to fully protect forest values during the construction
     operation . . . almost all road construction was accomplished
     with a large crawler (D-8 or D-9) with dozer.  In many cases
     this was the only equipment . . . Much of the road construction
     equipment was developed for wide highway and freeway construc-
     tion . . . Evidence was found that timber sale road inspectors
     adjusted their enforcement of specifications to meet the capa-
     bilities of the contractors available equipment" (8).
                                  259

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     Recommendations from this report include:  (l) Constraints on



the maximum size of equipment that can be used for a particular road



project.  (2) Directing and supporting inspectors to enforce specifi-



cations relating to equipment size etc. . .  (3) Revise cost estimating



guides to include costs of doing work with various sizes or kinds of



equipment.  (4) Make equipment manufacturers who are continually de-



veloping new machinery aware of management objectives, such as minimum



environmental impact roads, minimizing soil  erosion, sediment and



aesthetic impacts.




     The use of the shovel to accomplish roadway excavation on the



Olympic Peninsula and in southeastern Alaska is discussed earlier in



this chapter.   The shovel is also commonly used in other areas with



steep terrain for the circumstance of excavating full bench sections on



narrow roads with waste end hauled.  This method results in a much



higher unit earthwork cost than was previously experienced with a partial



bench and/or sidecast operation with bulldozer excavation.  It also re-



sults in less road miles being constructed in the short season available



in many high altitude areas.  Equipment specifically adapted or designed



for more economic full bench excavation work on narrow roads with end



haul is needed.



     Hartsog and Gonsior believe that specialized equipment is needed for




clearing on steep slopes.  On China Glenn, tractors often worked them-



selves into places low on the slope where they had to be winched upslope




by another machine.  They believe tractors with a low center of gravity



equipped with a brush blade are the best of  the present equipment.  The
                                  260

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purpose of specialized equipment would be to eliminate or reduce the




pioneer road required for present equipment because of the potential



contamination attendant to a procedure of excavating before clearing




is completed (14).



     The necessity for appropriate equipment to install drainage facili-



ties has been previously mentioned.
                                  261

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                     MAINTENANCE
     Concerning maintenance, Robert W. Larse has stated:

     "Planned regular maintenance is necessary to preserve  the
     road in its (as built) condition, but unfortunately is too
     often neglected or  improperly performed resulting in deter-
     ioration from the erosive forces of the climatic  elements
     as well as use ...  It is neither practical or economical
     to build and use a  road that requires no maintenance . .  .
     The additional expense of constructing a road,  with proper
     attention to its stability and proper drainage  can generally
     be amortized within a few years by an offsetting  lesser cost
     of upkeep where soil  erosion and sedimentation  are of  concern
     . . .  ." (5).

     Some observers believe that problems have occurred due to policies

that result in too many  miles of road being left open.   The decision as

to whether a particular  road should be left open is  not the sole

prerogative of maintenance personnel but is related  to transportation

and land management plans.  Blocking primary purpose logging roads off

when this purpose is complete can help eliminate road  surface damage

with attendant sedimentation caused by other uses during wet seasons.

     If a road is not to be used again for several years or is to be

permanently closed,  blocking a road to prevent further use  of the road

may not be  an effective  sediment control technique in  itself.  If the

drainage integrity and stability of the roadway cannot also be maintained,

additional  measures are  needed for minimizing sediment.   These practices

are described in the Intermittent and Short Term Use section of this

chapter.

     To facilitate and expedite maintenance operations and  procedures,

a complete  set of "as built" plans with a record of  all maintenance
                                  263

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operations and observations should be maintained and be readily available



to the maintenance engineer.  This record system will help to equip and



supply new personnel with all the previous experience and observations



of their predecessors.




     The "as built" records should contain the following information:



     1.  Complete job index.




     2.  Complete history of the project from start to finish



         of construction.



     3.  Photographic records.




     4.  Exact location of culverts and other drainage features.



     5.  Unstable conditions in relation to cut and fill slopes



         and roadway surface.




     6.  Wet areas that may have caused over excavation and replace-



         ment with selected backfill.




     7.  All major field changes that were made in the original plans.



     The greatest asset available for any maintenance program is the



experience history and knowledge gained by those who have in fact



accomplished the maintenance operation.  Usually this knowledge is not



recorded, but every effort should be made by management to keep com-



petent experienced knowledgeable maintenance personnel at their tasks



and/or available for consultation and advice.




     The maintenance discussion that follows is divided into five



parts:   (l) drainage system,  (2) road surface,  (3) remedial measures




for slides,  (/+) intermittent and short term use,  and (5) maintenance



chemicals.






                                   264

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                         DRAINAGE SYSTEM






     Drainage maintenance is not a spectacular task.   The greatest and




best accomplishments occur in wet ditches,  plugged culverts,  or slides




that impair roadways.  For forest roads, particularly in mountainous




areas, maintenance cannot be programmed on the yearly calendar but must




be accomplished when the individual site or circumstances dictate.




Little can be accomplished in snow or in frozen ground with the




possible exception of jacking in culverts or solid rock excavation.




Snow melts do not usually cause the maximum flows or carry fragmented




rock, boulders or fallen timber.  The time to accomplish the major




drainage maintenance is usually concurrent with the major forest




operations of cutting, hauling, planting or thinning.




     In spite of this peaking of labor demand, the maintenance




program should never be postponed.  Rules or procedures for drainage




maintenance can be set up only as guidelines because there is a wide




variance between localities, construction accomplishments, workable




seasons and climatic factors.  The following are offered as guidelines




only, as each area must modify or amend their procedures to suit their




circumstances.






CULVERTS  AND DITCHES






     Ditches, culverts and catch basins must be kept free of debris and




obstructions.  On new construction, catch basins may require frequent




cleaning,  perhaps after each major storm.  Grass in ditches should not




be removed during cleaning operations.  Shoulder and bank undercutting




must be avoided.  Damaged culverts should be repaired or replaced.





                                   265

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     Culverts and inlet structures should "be cleaned by flushing down-

stream only if adequate filtering to protect watercourses is available.

Debris from cleaning operations should be hauled to a stable waste site

far removed from any watercourse.

     "Regular inspections during or after storms will ensure
     good drainage because problems are detected before they
     become serious.  Inspections for detection of weaknesses
     in drainage systems are especially important on new roads.
     As a general rule, roads should be examined annually in
     the Spring after the first rains or at the start of snow
     melt" (43).

In Western Washington and Oregon, a fall inspection prior to winter

storms is good practice.

     Ditches and culverts are particularly vulnerable to debris block-

age when a logging operation is occurring on or adjacent to the road.

Blockage with limbs, needles and wood chunks can occur rapidly.  Main-

tenance personnel should be alert to the ongoing logging operations

and aware of their potential significance to the maintenance program.

     Live streams with culverts should be completely free of trans-

portable debris, for at least 100 feet upstream.  If the initial con-

struction did not call for debris deflectors or trash racks and sub-

sequent experience shows they are required, install them as part of

the maintenance program.  The downstream end should also remain free

flowing.  Debris should be removed from streams or channels by grapples

or tongs rather than by equipment in the stream bed.

     Ditch and culvert surveillance may be necessary on closed roads

particularly in seasons immediately after logging operations.  The

potential for debris blockage, although perhaps less with the road closure,

can still exist.

                                   266

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CUT AND EMBANKMENT SLOPES





      Cut and embankment slopes are so individualistic that only the




 most elementary precautions are set forth below.   Each slope must




 receive separate study.




      Erosion clefts in cuts may be filled with rock or coarse gravel




 to create a trickling water movement through the  rock fill material.




 Turf should be replaced in bare earth areas.




      Erosion clefts in embankments should be filled and turfed and




 the water from the roadway directed to a culvert  or flume.  In the




 event of indicated large movement, the slope may  be dewatered by hori-




 zontal drains, wells, or well points until the area becomes stable.




 Only pervious materials, preferably rock, should  be placed as embank-




 ment on water giving slopes.




      Berms at the top of embankments intended to  prohibit water from




 flowing onto the slope should be monitored for breaks or ruptures  and




 repaired as required.






                             ROAD SURFACE






      Road surfaces must be kept well crowned or sloped so they will




 drain.   Surface blading should preferably be accomplished when the




 moisture content of the material results in neither dust nor mud from




 the blading operation.  Particular attention should be accorded the




 road crown or slope just in advance of the wet season.




      Roads subject to traffic during the wet season will require con-




 tinual  monitoring for surface condition including ability to drain,
                                   267

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presence of rutting and loss of ballast.   Provisions should be made



for ballast replacement where necessary as a condition to continuing



operations on the road.  Roads sufficiently ballasted for dry weather



operations may not be satisfactory for all seasons.



     Surface cross drains should be cleaned as required after the



logging season to restore their functional ability.   If the cross



drains do not exist in a road intended for seasonal  closure, they




should be cut in advance of the rain and/or snow season.



     The snow removal operation can damage the road  surface by remov-



ing ballast and/or destroying the roadway crown.  Factors that contri-



bute to the potential for damage are improper snow removal equipment,



improper equipment operation and initiating snow removal at the improper



time.  Snow removal procedures should allow for proper drainage.



     Road condition has to be monitored relative to the freeze thaw



cycle.  The potential for surface disruption is greater when frozen




subgrade or surfacing begins to thaw.



     The foregoing expresses important provisions or guidelines for



road maintenance.  The most important guideline consists of management



educating the maintenance personnel about the importance of minimizing



sediment transport to ditches.  No one can control the amount or time



of rainfall or the amount and rate of snowmelt.  Therefore the only



control of sediment transport attendant to maintenance operations  is




by individuals.



     There will be circumstances both planned and unplanned when sedi-




ment from roadway surfaces  is transported to side ditches.  When this
                                    268

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     Slides cause many problems in conjunction with maintenance and



increased erosion potential along the road alignment.   Several of



these problems are discussed in the following paragraphs.






REMOVING SLIDE  DEBRIS




     Slide debris deposited on roadways may cause significant increased



sediment loads in established roadway drainage systems.   In some



cases it may cause erosion channels to develop outside of  established



drainages.  The removal of material on the road may be accomplished



by heavy construction equipment.  Sidecasting of the material should



not be allowed.




     Slide debris which is located downslope from the  logging road



poses a different and more difficult problem.  Most importantly, the




removal operations may trigger further movements.  Another problem



involved in removing the material is the possibility of damaging



surface vegetation and erosion control devices on the  downslope side



of the road.  Therefore, an evaluation of the potential for erosion



from the slide debris versus the potential for erosion caused by



the removal of the slide debris, including that from potential future



slides triggered by debris removal, should be made and carefully



examined before any removal is carried out.



     In many cases removal will probably be infeasible.   It may be



desirable to leave the material in place and shape and reseed it



or take other measures to reduce the potential for surface erosion.



Specific rules or guidelines for debris removal should not be formulated.




Each case should be evaluated on an individual basis and action taken



in response to the conditions encountered at each site.






                                270

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WASTING SLIDE DEBRIS




     Once the slide debris is removed the problem arises as to what




should be done with the material.  Slide debris is often composed




of a mixture of soil,  rock, and organic debris, and is usually very




wet.  Material in this condition normally cannot be placed and compacted




as fill within a roadway embankment.  However, the material may be




placed in end-haul disposal areas.  Proper placement and compaction




of this material must be achieved in order to limit erosion.  Again,




it should be emphasized that slide debris material should not be




sidecast from the roadway or placed in a noncompacted fill that is




susceptible to erosion.






RELOCATION  VS CORRECTION




     Proper evaluation of the erosion potential and the economics




of road relocation versus slide correction is essential, and many




factors should be considered before a decision is made.  Among these




are:  what caused the slide, how extensive is it, and will it reoccur?




These questions will be discussed in more detail in the following




section.  Before a decision is made, the amount of surface erosion




and mass wasting potential from construction of a newly relocated




alignment should be determined.  A new road may have a higher total




erosion potential than the erosion from the slide debris, particularly




if the general terrain is unstable or if the new alignment is of




considerable length.  New roads, particularly initially, often have




a higher erosion potential than the existing ones.  Correction of




the slide area may involve constructing retaining structures, installing
                                 271

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drains, reshaping slopes, and/or replacing fill in the roadway alignment.




Slide correction is often more desirable than constructing new roads.






FAILURE MECHANISM INVESTIGATION




     Before corrections can be made within a slide area,  the extent




of the slide, the reason for the slide,  and the potential for reoccurrence




must be determined.




     The first step in defining the failure mechanism should be a




detailed inspection by an experienced soils engineer or engineering




geologist.  From this inspection, an approximate failure plan can




be developed and possible causes evaluated.  In many cases, this




inspection is all that is required for a proper evaluation of the




failure.  In more extensive and complex slide areas, this intial




inspection should be supplemented with a detailed subsurface investigation.




This investigation would include drilling deep holes to obtain undisturbed




samples for strength testing, and installing piezometers within and




above the slide area.  In some cases, the installation of inclinometers




may be justified to determine if movement is continuing and to what




extent it may be occurring.  The amount and extent of this investigation




is dependent upon the conditions at each individual site.  In any




event, this work should be accomplished under the auspices of a specialist




in either soil or rock mechanics.
                                272

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                INTERMITTENT AND SHORT TERM USE V


     Problems arising both from overdesigned roads which do not  fit  the

terrain and from inadequately designed roads have been described.  Field

observations in Region X indicate that sediment  control practices  are

often neglected or ignored for low standard logging  roads.   These  are

variously described as "work", "branch",  "spur"  or "temporary" roads.

In most situations they are designed and constructed for relatively  low

volume of traffic, and intermittent or short term use.  As  used  in this

discussion, "temporary" means short term use.  Design criteria for such

roads usually include minimization of both investment and maintenance

costs.  Haul costs are generally of secondary consideration.

     The principles for incorporating appropriate sediment  control features

into planning, reconnaissance, design and construction have been described

in previous chapters.  These principles are applicable to all types  of

logging roads.  For example, a spur road constructed in the wrong  location

can cause as much water quality damage as a poorly located  higher  standard

road.

     Road maintenance procedures and appropriate options discussed

previously in this chapter are applicable to low-standard roads.  For
I/   Inclusion of this section in the final report is the result of
~    written comments received following the draft report review;
     and subsequent written and verbal communication with selected
     practitioners.
                                  273

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intermittent or short term use roads, additional options and techniques




are available for minimizing sediment production between use periods




or after use is concluded.  As noted previously in this report,  many




factors must be considered in order to rationally select suitable




options for a specific road.






INTERMITTENT USE






     Intermittent use logging roads are those which are planned for a




permanent transportation facility but are not intended for continuous




use.  Intervening time between use periods may range from several




months to several years.




     In addition to the many elements of consideration described




throughout this report, other factors may influence the selection of




maintenance options for these kinds of roads.  These factors include:




type of ballast or surfacing on the roadbed;  length of time between use




periods; construction method (sidecast or end haul); whether the road




existed previously or is the result of a planned design and construction




sequence; length of time a previously built road has been in place




(demonstrated stability); type of drainage structures; and cost effec-



tiveness .




     Even though an objective may be to minimize maintenance during




non-use intervals, periodic inspection of a road is needed to assure




that the water quality protection measures are performing as expected.
                                   274

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 Roadway






     Where the interval between use periods is relatively short, one




 approach is to block the entrance to the road to prevent unplanned use




 and  conduct needed maintenance throughout the non-use period.  Tech-




 niques for blocking a road include gates and a variety of crude and




 sophisticated physical barriers constructed from native materials




 (rock, slash, cull logs, etc.).




     A more comprehensive approach, in addition to blocking the road,




 includes installing a system of water bars and drainage dips (as




 described in the Drainage Design section); and stabilizing cuts and




 fills (as detailed in the Slope Stabilization section).  Scarification




 and  revegetation of the road surface may also be appropriate—depending




 upon the type of road surface, the erosion potential and the non-use




 interval.  These measures may be sufficient to stabilize the roadway




 during non-use periods, but supplemental maintenance may also be needed.




 Depending upon the drainage design some roadway renovation may be needed




 prior to re-use of the road.




     When the interval between use periods is long, additional options




 are available.  In some cases, the approach described in the previous




paragraph may be sufficient.




     Another method is to partially restore the original ground profile




 in order to convert some of the surface water flow created by the road




incision back to a subsurface flow and provide more efficient surface




runoff capability.






                                  275

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     The Panhandle National Forest in Idaho has developed a partial




restoration technique, called the "Kaniksu Closure", which involves




moving the outer road berm and part of the fill material and placing



it into the road cut area.  Figure 41 illustrates this method.  Where



terrain and road conditions permit the use of this technique without



loss of significant amounts of soil over the embankment edge, the work




can readily be accomplished with an angle-blade bulldozer.  Dave Rosgen,



hydrologist on the Panhandle National Forest reports that this method



is successful on side slopes up to 60 percent in northern Idaho.



Following the work, the site is revegetated.



     The "Kaniksu Closure" was developed initially to deal with an



existing transportation system.  Other field practitioners report that



this technique has limitations for use in areas with high precipitation;



on ballasted or surfaced roads; on end haul constructed roads; in some



soil types; and where the interval between use periods is relatively



short.  (Re-opening the road may result in more re-exposed roadway



surface than would result with another method.  Unless the interval



between use periods is fairly long,  this may negate some of the restor-



ation benefits).





Stream Channel Crossings






     Stream channel crossings on intermittent use roads deserve special



consideration.  Culvert installations with substantial fills are parti-



cularly vulnerable to failure as a result of debris blockage or simply
                                  276

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 Excavated
  mat trial
ve
                                     Original
                                   land slope.
Original
road prism
                                 kdjusttd
                                 road prism
                                        (Afitr Rosgen )
        Schematic
                  FIGURE 41   "KANIKSU CLOSURE"
                             277

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from being incapable of handling high runoff events.  Such problems



occur more often with unattended installations but can also occur—




especially during heavy runoff conditions—even when maintenance is



attempted.




     More options are available if the crossing installation is the



result of a planned design-construction sequence than if it is on a



road being re-used.






     Pre-planned Crossing.   For these installations, the basic alter-



natives are as described previously in this report—culverts; bridges;



or in some circumstances, fords.



     Techniques for culvert design, installation and maintenance



discussed elsewhere in this report are applicable.  There are some



additional methods used for dealing with intermittent use roads.



Information from field practitioners indicates that, where a culvert



installation is the best option, important design, construction and



maintenance criteria are:



     1.  Minimize the amount of culvert fill.



     2.  Use generous culvert end area estimates.



     3.  Design for a permanent installation.



     4.  Plan for supplemental maintenance "watch" if there



         is doubt about the ability of an installation to



         withstand extraordinary runoff events.



     5.  If a stable installation is not technically or



         economically feasible, include subsequent culvert






                                   278

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         removal as part of a planned process if it  can be




         accomplished with minimal water quality impact.




         If not, avoid such sites or select a safer




         installation.




     Another technique is to use "temporary" log stringer bridges in lieu




of culverts where the culvert installation requires  a large fill.  Many




of the installation criteria for protecting water quality described in




the Bridges portion of the Design chapter are also applicable to




temporary bridges.  Several different kinds of temporary bridge designs




are used in Region X—varying from simple, relatively crude structures




to more elaborate bridges designed for heavy traffic and several




seasons of use.  With short lapses between use periods, it  may be more




economical to install a longer life "temporary" bridge and leave it in




place.  With longer intervals of non-use it may be more advantageous to




use a minimal cost structure and remove it after use.  It should be




noted that the practice of placing logs across a stream channel and




placing an earth fill over the logs is neither a good water quality




management practice nor considered to be a "temporary bridge" as used




in this report.



     In certain situations (see Stream Crossing Methods subsection),




fords may be a suitable channel crossing installation.






     Existing Crossings.   If a channel crossing installation has




functioned satisfactorily for years (demonstrated stability) most field




practitioners contacted believe the best solution is to restore the
                                   279

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installation to its original stability and leave it in place.   The




restoration work may involve several elements of the installation other




than the crossing structure itself.   This may include removal  of stream




channel debris; and roadway reconditioning (e.g., reshaping,  cleaning



ditches, reopening drainage, revegetating, etc.) over and on approaches



to the crossing.



     However, if it is determined that there is a high risk of culvert



failure following the use period, the water quality management choices



are more difficult.  The basic options are continual maintenance or



removal of the installation—entirely or partially.  Factors which may



lead to & "high risk" determination include:  restoration to original



condition is not feasible; the hydrologic character of the channel and



upstream watershed has materially altered; unstable debris; and instal-




lation stability has not been demonstrated (e.g., high frequency of



failure of similar, nearby installations).  Continual, on-site main-



tenance watch before, during and after high runoff events—until the



installation becomes stable—is one way of reducing failure risk.



     If continual maintenance is not feasible, most practitioners



contacted believe that the best solution is to remove the installation.



This can be expensive and difficult to achieve without creating water




quality impacts.  However, care in timing  the removal operation, and



use of proper equipment can aid in reducing impacts.



     Where the total removal cannot be accomplished without substantial



impact because of prohibitive costs or technical infeasibility, a
                                  280

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partial solution is a relief dip in the culvert fill.   Rosgen reports




that this technique has been field tested on the Panhandle National




Forest and shows promise.  Figure 42 shows this technique in schematic




form.  The relief dip does not stabilize the fill.   Rather,  it reduces




the impact by directing the course of overflow water and reducing the




amount of potential sediment.






SHORT TERM USE






     Short term use (temporary) logging roads are those which are not




planned for re-use.  The general objectives for such roads should be to




design a facility which can be safely maintained during its life, which




can readily and safely be restored back to as nearly the original ground




conditions as feasible; and to plan to make the time period between




construction and restoration as short as practicable (within the same




season if feasible).   Locating temporary roads should be avoided in




areas where these objectives cannot be reasonably accomplished.






Roadway






     One alternative  is to stabilize the road prism as permanently as




feasible.  Methods for accomplishing this include:  blocking the road to




further entry;  installing a stable system of water  bars, drain dips, and




outsloping  (where suitable); revegetating the cut  and fill slopes and




road surface; and establishing trees if the site was previously forested.




These practices and limitations for using them are  discussed elsewhere
                                   281

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                             Original
                 excavated material to
            roacf approatkef
                                              Original
                                              drainage prof He
VERTICAL
  Culvert
                        Drain and vegetate
                         (disperse water)
                                A
V       Configuration on exposed
irrn ~~ to disperse surface  runoff—
KvA (fmatf. one foot or lest contour trench*)
\   i                                     •
                                   (Atttr
          FIGURE  42    MODIFIED CULVERT REMOVAL
                           282

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 in this report.  This approach may be most suitable where an existing,




 stable roadway has been reopened (but no further use is planned).  If




 the watershed character has not been materially altered and if the




 past performance of these methods has been good for similar sites,




 they may also be adaptable for newly constructed temporary roads.




   The "Kaniksu Closure" method along with tree establishment as




 appropriate will, in general, result in a more complete restoration




 of the water handling characteristics of the site.  Taking into account




 the previously described limitations of this method, it can be used for




 existing and newly-constructed roads.  The U.S. Forest Service, Region 6,




 uses a similar method as one option for obliterating temporary roads




 constructed under timber sale contract.




   A more comprehensive (and usually considerably more expensive)




 technique is to completely restore the original ground profile.  As used




by the U.S. Forest Service, Region 6, this method—sometimes termed




 "deconstruction"—is to temporarily store excavated material and then




pack it back into the roadway following completion of use.  This




 technique was developed primarily to deal with critical terrain and




high precipitation problems in portions of the Pacific Border Province.




 The more common practice is to sidecast excavated material and, following




use of the road,  pull it back up into the road prism with shovel or




dragline.   When this practice is used in precipitous terrain,  it is




imperative that it be used only where the roadway excavation and




subsequent restoration can be accomplished during the same summer season.
                                  283

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Sometimes the excavated material is endhauled, stored on a stable waste




site and then placed back in the road prism following use.  In this




case, if the restoration cannot be completed during the first season,




additional measures may be needed to prevent erosion of the roadway and



the waste material.



    After "deconstruction" is completed, the restored ground is revege-



tated, including tree establishment as appropriate.



    It is apparent that even temporary logging roads require thoughtful



planning and design in order to most effectively achieve desired water



quality objectives throughout the life, care, and obliteration of the



facility.





Channel Crossings






    Sediment control objectives for channel crossings on temporary



logging roads should include the following:



    1.  Design crossings which:



        (a)  can be installed with minimal water quality impact;



        (b)  remain stable during use; and



        (c)  can be readily removed without significant impact.



    2.  After use, stabilize the channel to prevent soil or debris




        from moving into the stream during high runoff events.



    3.  Perform the restoration work in a timely manner.



    Generally, temporary bridges are the most suitable for meeting



these objectives.  Where bridges are not feasible, culverts may be a
                                   284

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 suitable alternative.  In limited circumstances (see Stream Crossing




 Methods subsection), properly designed fords may be satisfactory.




     However,  location and construction of temporary roads should be




 avoided in  those  situations where there are not suitable alternatives




 for  reasonable accomplishment of the channel crossing objectives.








                    ROAD MAINTENANCE CHEMICALS






     A wide variety of materials is  used  to maintain logging  roads.




Chemicals,  as deicers,  are  used on a limited basis compared to dust




palliatives.  Some of the most common asphalt products and other




chemicals used on logging roads are  in Table 16.   Potential hazards  and




use criteria are also included.   The criteria for minimizing  water




pollution from many of the  chemicals used on logging roads have many




common features as shown in Table 16.






DUST PALLIATIVES






     Several kinds of materials are  used  in dust  coating logging roads.




The most common materials used are oil based.  The principal  objective




is to stabilize soil in the road bed.  In many parts of the Region,  the




soils on roadbeds are very friable when dry,  creating excessive dust with




continuous road use.  Reducing dust  emissions is  necessary for safety or




to improve visibility,  aesthetics,  and to minimize particulate intro-




duction into air and water.
                                   285

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                                                                                      TABLE 16
                                                                           CHEMICALS USED ON LOGGING ROADS1
00.
Compound
Herbicides
Asphalt Products
Use
Roadside Vegetation
Control
Dust abatement/paving
Potential Hazard
Poisoning, etc.
Coating of gravel beds.
Hazard From
Spillage, over spray
ingestion
Spillage, over-application.
Use Criteria
Should be:
Approved chemicals
Applied by qualified
applicators
Standard specifications
            Emulsified Asphalts



            Paving Grade


            Cutbacks
Dustoils
 Arcadia
 Reclaimed wasteoil
 PS-300
                           Paving


                           Paving,  dust abatement




                           Dust abatement
Introduction of asphalt
 into waterway when
 mixing in tankers.

As above.
Fire.

As above
Fire as with paving grades.
Introduction of light & middle
 distillate volatiles

Aquatic life

May "be toxic to aquatic
 organisms	
                                                                                          Siphoning Action,  runoff
Overheated product
Spillage, over application

Spillage, over application
 leaching
                                     and spill reporting.
                                    Require air gap between
                                     pick up & delivery point
Use specified temperature
 ranges
Standard specifications & spi
 spill reporting
            Na Cl
                                       Deicing, dust abatement
                                                          Detrimental to atmospheric
                                                           & aquatic plant growth &
                                                           fishery.
                                Excess
                                Na( + )ion: through over applica-
                                 tion & leaching.
                                    This has received only limited
                                    use historically due to most
                                    roads being allowed to snow in.
                                                                                                      Cl combines to HC1 form in water.   Control by rates of application
            Ca Cl,
                                       Dust abatement
                                                          Detrimental to fishery
                                Leaching-Cl combining to HC1
                                 form in water, reducing avail-
                                 able oxygen.	
                                                                                                                                          Not used in wet climates
                                                                                                                                          Control by rates of application
            Reynolds Road Packer
                                       Soil Stabilizer
                                                                                                                              Individual project control.
                                                                                                                              Very limited use currently.
            Sulfite Waste pulp
             Liquor
                                       Dust abatement
                                                                      Fisheries
                                                                                          Spillage,  over-application
                                                                                           and leaching.	
                                                                    Controlled rates of appli-
                                                                     cation.
            Portland Cement
                                       Soil stabilizer, concrete


            I/ Modified from information from Region  6, USFS - 5/10/74
                                                          Coating of fish gills
                                                           decreasing oxygen
                                                           assimilation.
                                Introduction of cement into
                                 waterway.
                                    Should not use above hatchery
                                     installation & control of
                                     operation in all cases.

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Pollution from Oil Based Dust Palliatives


     Pollution resulting from oil discharges from logging roads or

spills related to uses of oils may be in the form of floating oils,

emulsified oils, or solution of the water soluble fractions of these

oils (104).  Floating oils may interfere with reaeration and photo-

synthesis and prevent respiration of aquatic insects which obtain

their oxygen at the surface.  Free and emulsified oils may act on the

epithelial surface of fish gills interfering with respiration, or they

may coat and destroy algae and other plankton.  Oil sediments may coat

the bottom of waters destroying benthic organisms and altering spawning

areas.

     The water soluble fraction of oils may be very toxic to fish.

Apparently the aromatic hydrocarbons are the major group of acutely

toxic compounds in oil residues (104).  Because of the wide range of

results obtained in toxicity tests for oily substances, safe concen-

trations for the many compounds used in dust abatement cannot be

accurately astablished.

     The 96 hour LC^g  concentrations for various compounds of oil (all

not used in dust coating logging roads) range from 5.6 mg/1 for nephenic

acid to 14,500 mg/1 for No. 2 cutting oil (104).  Stickleback fish tests
I/  LC^Q, TL/jQ - In toxicity studies it is the dosage required to kill
~~   50$ of the test population.  It is expressed by the weight of the
    chemical per unit of body weight.  The designations are used as
    reported in the reference cited.
                                   287

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indicated a toxicity for CSS-1 asphalt emulsion of  LC$Q  (96 hour)  of



9,000 mg/1.  CMS-1 and CMS-2 asphalt emulsion had a LC50 of 45 mg/1 (105).



Both CSS-1 and CMS-2 are used for dust coating logging roads.  The




toxicity information indicates that a large  quantity of  these materials



are necessary for lethal effects.  There is  evidence that oils may




persist and have subtle chronic effects (104).



     Laboratory simulation studies on water  solubles removed from  surfaces




stabilized with emulsified asphalts were conducted  by Nielson  (106) in the



Region.  The studies indicated that a large  amount  (over 40$)  of asphaltic



material could be washed from a road surface during the  first  few  days



after application of an emulsion mix.  A much larger amount of leaching



occurred during extreme laboratory conditions than  is likely to  occur



in the field.  After a few days of curing, the amount removable  declined



rapidly to approximately two percent of the  amount  applied.  The amount



removed remained nearly constant for the study's 30-day  duration.



     Two rural roads in New Jersey treated with waste crankcase  oil were



examined by Freestone (107) to determine whether or not  oil left the  road.



Waste crankcase oil is not commonly used for dust coating logging  roads;



however, some of the study's conclusions may apply to other oil  dust



palliatives.  Analyses indicated that roughly one percent of the total




oil estimated to have been applied remained in the  top inch  of road



surface material.  Oil penetration below the top inch of the road  was



minimal.  Oil could have left the road surface by several means  such  as



volatilization, runoff, adhesion to vehicles, adhesion to dust particles
                                  288

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with wind  transport  and penetration into  the  road surface.   Oil remaining




in the road  surface  may have  also been biodegraded.




     Most  of the  studies  related to water quality impacts of oils  have




been concerned with  lethal  levels and  their effects  on the  aquatic




environment.  Many of  the studies are  documented  in  water quality




criteria reports  (104, 108).   In a  recent study by Burger (109), acute




toxicity bio-assays  of PS-300 oil on juvenile Coho salmon were conducted




on two weight classes.  Comparable  TLcQ values of 1,350 and 1,500  mg/1




resulted,  indicating no definite difference in toxicity due to size  or




age.  With the utilization  of reduced  concentrations,  the most obvious




long range effect was  that  concentrations of  75 mg/1 and 40 mg/1 were




not sub-lethal.  Another  finding by Burger was  that  long-term exposure




to reduced oil concentrations affected the feeding behavior of the test




fish, resulting in weight loss and  increased  susceptibility to disease.






Control of Pollution from Oil Dust Palliatives






     As defined in Standard Methods  (110), any amount  of oil and grease




in public water supplies  will cause  taste, odor and  appearance problems




(110,111,112) and may be  detrimental to conventional treatment processes.



It is virtually impossible to express  limits  in numerical units for




allowable  concentrations  in waters.  Because  of the  difficulties in




establishing  safe levels,  the maximum  allowable concentrations can only




be determined by bio-assay procedures  and by  an evaluation  of the




chemical composition on a case by case basis.  This  procedure should be
                                  289

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used when water uses must be protected,  and dust palliatives pose a




significant pollution potential.




     Criteria for controlling pollution from oil emulsions are avail-




able from a number of sources such as manufacturers,  distributors,




agencies and groups using large quantities on a continuous basis,




water pollution control agencies, literature from research and others.




     Oil Spills.   The greatest potential for serious water quality




impacts associated with the use of oil dust palliatives is the potential




of oil spills.  Because of the steep and dissected topography, and the




use of many minimum standard roads, the potentials of oil spills are




increased.



     Recent rules and regulations that became effective January 10, 1974,




related to Section 311 (j)(l)(c) of the FWPCA as amended, are designed




to prevent discharges of oil into the waters of the United States and




to contain such discharges if they occur.  The regulations endeavor to




prevent such  spills by establishing procedures, methods,  and  equipment




requirements  of owners and operators engaged in storing,  processing or




consuming oil (Environmental Protection Agency, Oil Pollution Prevention,




Federal Register, Volume  38, No. 237 - December 11, 1973).  The  regula-




tions  apply to facilities that  store oil  on sites.




     Owners or operators  of facilities that have discharged or could




reasonably be expected to discharge oil  in harmful quantities (those




that violate  applicable water  quality  standards, cause  a  film or sheen




or discoloration of  the  surface of the water or adjoining shoreline,  or
                                   290

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cause a sludge or emulsion to be deposited beneath the surface of the




water or upon adjoining shorelines) into or upon the waters of the




United States or adjoining shorelines shall prepare a Spill Prevention




Control and Countermeasure Plan (SPCC Plan).  The SPCC Plan if properly




prepared and implemented should minimize the water quality impacts of




oil spills associated with dust-coating logging roads.




     The rules and regulations indicate that the SPCC Plan shall be




carefully thought-out, prepared in accordance with good engineering




practices, and have the full approval of management at a level with




authority to commit the necessary resources.  If the plan calls for




additional facilities, procedures, methods, or equipment not yet fully




operational, these items should be discussed in separate paragraphs and




the details of installation and operational start-up should be explained




separately.  The complete SPCC Plan shall follow the sequence outlined




in the Federal Register citation above, and include a discussion of the




facilities' conformance with the appropriate guidelines listed.  The




criteria below summarize pollution control techniques being used or




recommended by the various user groups.




     Contvol Practices.   Acceptable limits and concentrations of oils




in water should be achieved under the following practices and conditions:




     a.  There is no visible oil on the water surface.




     b.  Concentrations of emulsified oils do not exceed 1/20 (0.05)




         of the 96 hour LCjg value determined using the receiving




         water in question and the most important species in the area.
                                  291

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c.  Concentrations of hexane extractable substances (exclusive



    of elemental sulfur) in air-dried sediments do not exceed



    1,000 mg/1  on a dry weight basis.



dk  Dust palliative materials are not dumped into an area



    where they may flow into streams or bodies of water.



e.  Dust palliative materials are not applied during rainy



    weather or runoff, or during a threat of rain within a



    4.8 hour period after application (this is obviously a




    judgment factor).  Curing time of the product is the



    important factor.



f.  The road surface is watered prior to application to



    assist in penetration.



g.  A small berm or wrinkle is temporarily made on either




    road shoulder to prevent the material, in its liquid state



    from running off the road during application.



h.  Dust oils are applied only when the roadbed has been



    properly graded, watered, shaped and compacted, and when



    the atmospheric temperature in the shade is above 13°C



    (55°F) and steady or rising.



i.  Many of the techniques discussed in Part II for minimizing



    sedimentation such as buffer strips and drainage design,



    will also reduce discharges of oil dust palliatives from



    roads if properly used.



j.  Properly prepare and implement a Spill Prevention and



    Countermeasure plan where necessary.






                            292

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OTHER  CHEMICALS






Salts






     Sodium chloride and calcium chloride are the only salts known to




be used on logging roads in Region X.  Salts are used to control snow




and ice (deicing) and dust.  The amount of salts used and the degree




to which they are used are not quantified.  Information received from




the U.S. Forest Service, Region 6 (Table 16) indicates that these salts




are probably used only to a limited and localized degree in the Region.




     Most of the water quality impact information and data on the use




of salts on roads relates to snow and ice control on paved highways




and streets.  A state-of-the-art report, Environmental Impact of




Highway Deicing (113) has been published.  This 1971 report extracts,




summarizes, and references much of the research and information on the




subject.  Information is also available on the use of salts for dust




abatement on unpaved rural roads and on logging roads.




     Additives are also commonly used in the salts.  These are anti-




caking agents, corrosion inhibitors and rust inhibitors.




     Because of the much more limited application of salts on logging




roads, it is assumed that the total magnitude of potential problems




would be far less than on highways and streets.  However, for a specific



case, the problem could be similar.  Therefore, it is assumed that the




kinds of water quality impact problems created by highway salting can




be extrapolated to logging roads as potentially similar.
                                  293

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     Historically, snow plowing, tire chains and a limited amount of



sanding have been the principal snow control measures on logging




roads.  Generally, deicing salts—principally calcium chloride—are used




only on paved roads.  As more logging roads become paved there may be



an increased use or interest in using salt for deicing.



     Calcium chloride alone but usually a mixture of calcium and



sodium chlorides are used for dust abatement.  Wright (114) reported




that a 50:40 mixture of sodium chloride-calcium chloride applied at



9,000 pounds per mile, for a 20 foot application width (4/10 kilogram/



meter^), proved both practical and reasonably effective for dust abate-



ment on a logging road in Canada.




     Oil palliatives and sulfite pulp liquor waste are used more



extensively for dust abatement than salts in Region X.  However, petro-



leum supply shortages may result in a shift from oil palliatives to



more salts and pulp liquor use.




     Several problems associated with use of salt on highways are



pertinent to potential water quality impacts if salts are used on



logging roads.



     The potential toxicity of water polluted with road salts is two-fold-



the salts and the additives.  Excessive sodium concentrations in drinking



water may be harmful to some people with heart or kidney disease (115).



Schraufnagel (116) refers to studies done on chloride levels harmful



to freshwater fish life—with the lowest lethal level of 400 mg/1 in



one study to the highest, 8,100 to 10,500 mg/1 in another.  (Sea water



has a chloride concentration of about 19,000 mg/1).
                                  294

-------
     Evidently, saline concentrations must be at relatively high levels

to seriously affect fish life.  However, the salt additives present a

different picture.  The highway deicing report (113) concludes:

     "The special additives found in most road deicers cause
      considerable concern because of their severe latent
      toxic properties and other potential side effects.
      Significantly, little is known as to their fate and
      disposition, and effects on the environment.  The com-
      plex cyanides used as anti-caking agents and the
      ehromate compounds used as corrosion inhibitors have
      been found in public water supplies, ground waters....
      The phosphate additives....may contribute to nutrient
      enrichment in lakes, ponds, and streams...."

     In addition to potential toxic effects, deicing salts have resulted

in ground water contamination—including public and domestic water sup-

plies, ponds and streams (113).  The Public Health Service Drinking

Water Standards lists the recommended maximum chloride concentration as

250 mg/1, but chromium and cyanide concentrations of .05 mg/1 and  .2 mg/1,

respectively, are grounds for rejection of the water supply (117).

     Several authors and publications have reported the movement of

deicing salts from road surface (113, 118, 128).  Maximum concentrations

of salts may be found at soil surfaces nearest the road.  However, salts

are readily leached from the soil surface and into subsurface flow.

Kunkle (119) reports that the highest concentration of chloride in

study streams occurs during summer low-flow—apparently the result of

ground water movement into the streams.   (Note: concentrations, i.e.,

mg/1 were higher in the summer; total salt delivery was greater in the

spring but at a lower concentration because of dilution).
                                  295

-------
     For deicing salts,  three major application problems were reported



(113); over-application,  misdirected application,  and improper storage



of stockpiled salts.



     Two comprehensive documents,  Manual for Deicing Chemicals:  Appli-



cation Practices (120) and Manual for Deicing Chemicals;  Storage and




Handling (121) are recommended source references to consult for specific



guidance in storing and applying deicing salts.



     Two key needs brought out in the above application practices manual



are knowing how much salt is actually being applied (i.e., verifying the



calibration) and making only the essential minimum number of applica-



tions.



     The following practices and procedures should assist in minimizing



water quality impacts of salts on logging roads.




     1.  Limit the use of salt for snow and ice control



         on logging roads to minimum essential needs.



     2.  In lieu of salts for ice and snow control, consider



         snow plowing, chains and sanding to the extent feasible.



     3.  If there is compelling reason to use salt deicers, the



         following should be considered:



         a.  Use only enough salt to provide a safe driving surface.



             This includes (l) monitoring the amount of salt actually



             applied frequently enough to ensure that equipment cali-




             bration is resulting in the prescribed application rate; and



             (2)  making only the minimum needed number of applications




             during each storm.






                                   296

-------
         b.   Salt only on  steep grades,  at major intersections




              and at  stop points.




         c.   Favor sand-salt mixtures in lieu of straight salt




              applications.




         d.   Avoid application near streams or lakes.




         e.   Avoid spillage off the road surface—i.e., keep the




              salt on the road.




         f.   Locate  storage areas where  ground water—as well as




              surface water—contamination threat is minimal.




         g.   Protect salt piles from exposure to moisture.




     4.  For  dust abatement purposes, utilize the following practices:




         a.   Apply only enough salt to provide the desired level of




              dust abatement.




         b.   Ensure  that the prescribed  application rates are what




              is actually being applied.




         c.   Where appropriate, consider items 3  e. thru g. above.






Pulp Wastes






     Sulfite waste liquor (SWL) has apparently been used for road dust




abatement for many years (122).  Pearl (123) reports that the largest




use of crude  spent sulfite liquor is for roadbinding (including dust




abatement) purposes—with an estimated 125 million pounds used annually,




nationwide.  Authors in other countries have also reported on the use of




pulp wastes in road construction (124).
                                  297

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     Pulp liquor is a relatively inexpensive and fairly effective dust



abatement material for logging roads.   It tends to leach out more



rapidly than oil palliatives and therefore requires more frequent



application to produce a similar degree of dust control.  As a result,




use of oil palliatives has increased in the past.   As previously noted,



petroleum shortages could alter this trend.




     The pollution characteristics of pulping wastes (pertinent to



roads) are their high biochemical oxygen demand (BOD) and their



toxicity (125).  The exact constituents responsible for toxicity are



not well known (125 ).




     The high BOD agents in the waste liquor tend to oxidize quickly on



the road surface.  This suggests a general pollution-minimizing



principle:  control the application of waste liquor so that it does not



run off the road surface at the time of application.



     Strombom states that application rates for pulp wastes vary



depending upon the porosity of the surface treated—with as little as



1/10 gallon per square yard (4/10 liter per meter^) on denser road sur-



faces to 1/2 gallon per square yard (2-2/10 liter per meter^) on porous



surfaces (126).  A Canadian report describes test results of application



rates of about the same magnitude for calcium lignosulfate (pulp liquor)



(127).



     Practices and methods to help minimize water quality impacts from



pulp waste liquors are as follows:
                                  298

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     1.  Control application—including application rates, use of




         equipment, and weather conditions—to prevent free runoff




         of the chemical from the road surface, i.e., ensure that




         the chemical stays on the road.  Some techniques  to help




         achieve control are:




         a.  Using temporary retaining terms at the roadway edges;




         b.  Making trial applications and evaluations to ensure




             that the calculated application rate is penetrating




             correctly;




         c.  Not applying the chemical during or immediately




             prior to rain;




         d.  Providing adequate training, performance standards, and




             supervision for application personnel and equipment.




     2.  Avoid applying the chemical where the road is close to a




         stream unless there is an adequate filter strip between




         the road and the stream.




     3.  Prevent spillage into or near streams.




     4.  When cleaning out chemical storage tanks or application




         equipment tanks, dispose of the rinse waste fluids on the




         road surface or in a place away from potential water




         contamination.






Others




     There are a number of trade name products developed for use as




road-binders.  In many cases, the chemical composition of these products
                                  299

-------
is not public information,  making it difficult to assess potential water



quality impacts.  Toxicity tests can be conducted for materials of



unknown composition.  However,  these tests have limited potential for



evaluating other than short-term effects on the tested organisms.



Knowledge of the constituents of a substance is a key to a comprehensive



evaluation.



     Impartial groups are available for making evaluations on a




confidential basis.  Data needed for evaluation of a product are:



(a) name and amount of each constituent; (b) associated technical



specification detail; and (c) specific directions, if any, for appli-



cation.  Sometimes an evaluation can be made on this basis alone; but



in some cases, further toxicity studies may be necessary.



     Specific recommended practices should be tailored for each product.



However, some general recommended practices are listed below.



     1.  Ascertain the chemical composition of each product.



     2.  Evaluate each product for its potential hazard.



     3.  Do not use products with demonstrated or suspected high



         toxicity.



     4.  Incorporate water quality needs into application



         specifications.



     5.  Use those practices described previously in this



         section, as applicable.
                                  300

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                                REFERENCES

 Text
 No.

 1.   Brown, George W.,  "Forestry and Water Quality," School of Forestry,
      Oregon State University, OSU Bookstore, 74 pages, 1972.

 2.   Fredriksen, R. L.,  "Erosion and Sedimentation Following Road Con-
      struction and Timber Harvest on Unstable Soils in Three Small
      Western Oregon Watersheds," USDA Forest Service Research Paper
      PNW-104, 15 pages,  1970.

 3.   Swanston, D. N., "Principal Mass Movement Processes Influenced by
      Logging, Road Building, and Fire," Proceedings of A Symposium on
      Forest Land Uses and Stream Environment, Oregon State University,
      August 1971.

 4.   Megahan, Walter F.  and Walter J. Kidd, "Effects of Logging Roads
      on Sediment Production Rates in the Idaho Batholith," USDA Forest
      Service Research Paper INT-123, 14 pages, May, 1972.

 5.   Larse, Robert W.,  "Prevention and Control of Erosion and Stream
      Sedimentation from Forest Roads," Proceedings of A Symposium on
      Forest Land Uses and Stream Environment, Oregon State University,
      August 1971.

 6.   Gonsior, M. J., and R. B. Gardner, "Investigation of Slope Failures
      in the Idaho Batholith," USDA INT-97, 34 pages, June, 1971.

 7.   Crown Zellerbach Corporation, "Environmental Guide, Northwest Timber
      Operations," 32 pages, July, 1971.

 8.   U. S. Forest Service Region 6, "Timber Purchaser Road Construction
      Audit."  A Study of Roads Designed and Constructed for the Harvest
      of Timber, 31 pages, January, 1973.

 9.   Siuslaw National Forest, Oregon, "Implementation Plan" to the Region
      6 Timber Purchaser Road Construction Audit, 23 pages, June, 1973.

10.   Boise National Forest, Idaho, "Erosion Control on Logging Areas,"
      36 pages, March, 1956.

11.   Rothacher, Jack S.  and Thomas B. Glazebrook, "Flood Damage in the
      National Forest of Region 6," USDA Pacific Northwest Forest and Range
      Experiment Station, Forest Service, Portland, Oregon, 20 pages, 1968.

12.   U. S. Bureau of Land Management, "Roads Handbook."  9110-Road, Trails,
      and Landing Fields, 200 pages approx.
                                    301

-------
                          REFERENCES (Cont'd)


Text
No.

13.  Forbes, Reginald D., "Forestry Handbook."  Ronald Press Company,
     New York, 1100 pages approx., 1961.

14.  Hartsog, W. S. and  J. J. Gonsior, "Analysis of Construction and
     Initial Performance of the China Glenn Road, Warren District, Payette
     National Forest."  USDA Forest Service INT-5, 22 pages, May, 1973.

15.  U. S. Forest Service Region 6, "Forest Residue Type Areas."
     Unpublished map of Region 6 showing geomorphic provences, timber
     species associations and geomorphic sub-provences, 1973.

16.  Snyder, Robert V. and LeRoy C. Meyer.  "Gifford Pinchot National
     Forest Soil Resource Inventory," Pacific Northwest Region, 135 pages,
     July 1971.

17.  Snyder, Robert V. and John M. Wade, "Soil Resource Inventory, Snoqual-
     mie National Forest."  Pacific Northwest Region.  228 pages, August 15,
     1972.

18.  United States Department of the Interior,  Bureau of Land Management
     Oregon State Office, "5250 - Intensive Inventories."  15 pages,
     Feb.  7, 1974.

19.  Burroughs, Edward R. Jr., George R.  Chalfant and Martin A. Townsend,
     "Guide to Reduce Road Failures in Western Oregon."  110 pages, Aug. 1973.

20.  Jennings, John W. "A Proposed Method of Slope Stability Analysis for
     Siuslaw National Forest," submitted to Forest Supervisor Siuslaw
     National Forest,  37 pages, May, 1974.

21.  Hendrickson, Larry G.  and John W.  Lund, "Highway Cut and Fill Slope
     Design Guide Based on Engineering Properties of Soils and Rock,"
     paper given at 12th Annual Symposium on Soils Engineering, Boise,
     Idaho, 35 pages,  1974.

22.  U. S. Forest Service Region 6, Supplement  No. 19 to the "Transportation
     Engineering Handbook"  24 pages, Feb. 1973.

23.  Swanston, Douglas N.  "Judging Landslide Potential in Glaciated
     Valleys of Southeastern Alaska."  An article appearing in The Explorers
     Journal, Vol. LI, No.  4.   4 pages, Dec. 1973.
                                   302

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                          REFERENCES (Cont'd. )
Text
No.

24.  Swanston, Douglas N.  "Mass Wasting in Coastal Alaska," USDA Forest
     Service Research Paper PNW-83.  15 pages, 1969.

25.  Chow, Ven Te, Handbook of Applied Hydrology, McGraw-Hill Book
     Company, 1964.

26.  Wischmeier, W. H., and D. D. Smith.  Predicting Rainfall-Erosion
     Losses From Cropland East of the Rocky Mountains.  Agr. Handbook 282,
     U.S. Govt. Print. Office, Washington, D. C., 1965.

27.  Musgrave, A. W., "The Quantitative Evaluation of Factors in Water
     Erosion - A First Approximation," J. of Soil and Water Conservation,
     Vol. 2, pp. 133-138 (1947).

28.  Dissmeyer, G.E., "Evaluating the Impact of Individual Forest Manage-
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29.  U. S. Environmental Protection Agency, Processes, Procedures, and
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     1973.

30.  California State Water Resources Control Board, A Method for Regula-
     ting Timber Harvest and Road Construction Activity for Water Quality
     Protection in Northern California, Volume II, Publication No. 50, 1973.

31.  Wischmeier, W.H., and L.D. Meyer, Soil Erodibility on Construction
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     Erosion:  Causes and Mechanisms;  Prevention and Control, 1973.

32.  Wischmeier, W.H., C.B. Johnson, and B. V. Cross.  A Soil Erodibility
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33.  Meyer, L.D. and L.A. Kramer,  Relation between Land-Slope Shape and
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34.  Meyer, L.D., W.H. Wischmeier, and W.H. Daniel, Erosion, Runoff,  and
     Revegetation of Denuded Construction Sites, Trans. ASAE, Vol. 14,
     1971, pp. 138-141.
                                   303

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                           REFERENCES (Cont'd.)
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35.  Meyer, L.D., W.H., Wischmeier, and G.R.  Foster.  Mulch Rates
     Required for Erosion Control on Steep Slopes, Soil Sci. Soc. Amer.,
     Proc. Vol. 34, 1970, pp. 928-931.

36.  Gardner, R.B., Major Environmental Factors that Affect the Location
     Design, and Construction of Stabilized Forest Roads, Reprinted from
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37.  United States Geological Survey, Quadrangle Maps, 7.5 and 15 Minute
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38.  Hershfield, D. M.:  Rainfall frequency atlas of the United States, for
     durations from 30 minutes to 24 hours and return periods from 1 to 100
     years, U.S. Weather Bur. Tech. Rept. 40, May, 1961.

39.  Probable maximum precipitation and rainfall-frequency data for Alaska
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40.  Western Forestry and Conservation Association, An Introduction to the
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41.  The Asphalt Institute, Soils Manual for Design of Asphalt Pavement
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42.  Federal Water Pollution Control Administration, Northwest Regional '
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43.  Rothwell, R.L., Watershed Management Guidelines for Logging and Road
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44.  Oregon State University, Proceedings of a Symposium on Forest Land
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45.  Renner, F. G., Conditions Influencing Erosion on the Boise River
     Watershed, U. S. Dept. Agr. Tech. Bull. 528, 1936.
                                   304

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                          REFERENCES (Cont'd.)
Text
No.

46.  Packer, Paul E., and George F. Christensen, Guides for Controlling
     Sediment from Secondary Logging Roads, U.S. Forest Serv., Inter-
     mountain Forest and Range Exp. Sta., 1964.

47.  Hvorslev, M. Juul, Subsurface Exploration and Sampling of Soils
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48.  American Association of State Highway Officials, Standard Method of
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49.  Megahan, Walter F., "Subsurface Flow Interception By a Logging Road
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50.  Western Wood Products Association, "Forest Road Subcommittee Minutes",
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51.  Gardner, R. B., "Forest Road Standards as Related to Economics and the
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52.  Tangeman, Ronald J., "A Proposed Model for Estimating Vehicle Operating
     Costs and Characteristics on Forest Roads," USDA Forest Service,
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53-  U.S. Environmental Protection Agency, "Comparative Costs of Erosion and
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54.  Prellwitz,  Rodney W., "Simplified Slope Design for Low Standard Roads
     in Mountainous  Areas," USDA Forest Service, Missoula, Montana, 19 pages,
     Unpublished, not dated.

55.  Haupt, Harold F.,  "A Method for Controlling Sediment from Logging Haul
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     Range and Experiment Station, Ogden,  Utah, June, 1959, 22 pages.

56.  Packer, Paul E.,  "Criteria for Designing and Locating Logging Roads to
     Control Sediment," reprinted from Forest Science, Volume 13, Number 1.
     March,  1967, 18 pages.
                                   305

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                          REFERENCES (Cont'd.)
Text
No.

57.  Franklin, Jerry F. and C.  T.  Dyrness, Natural Vegetation of Oregon
     and Washington, USDA Forest Service, Pacific Northwest Forest and
     Range Experiment Station,  General Technical Report PNW-8, Portland,
     Oregon, 1973.

58.  Becker, Benton C., and Mills, Thomas R., and The Maryland Dept. of
     Water Resources, Annapolis, Md.;  Guidelines for Erosion and Sediment
     Control Planning and Implementation;Office of Research and Monitoring
     U.S. Environmental Protection Agency, EPA-R2-72-015.  August 1972.

59.  Dyrness, C. T., Grass - Legume Mixtures for Roadside Soil Stabiliza-
     tion, USDA Forest Service, Pacific Northwest Forest and Range Experi-
     ment Station Research Note PNW-71.  1967.

60.  Corliss, John, Regional Soil Scientist, USDA Forest Service, Pacific
     Northwest Region, Portland, Oregon, personal communication, May 28,
     1974.

61.  Stephens, Freeman R., Grass Seeding as a Site Preparation Measure for
     Natural Regeneration in Southeast Alaska;  USDA Forest Service, Alaska
     Region, September 1970.

62.  Swanson, Stanley L., Legumes and Other Plants for Cover, Soil Conser-
     vation Service, Plant Materials Center, Corvallis, Oregon Bulletin.

63.  Kay, Burgess L., "Hydroseeding", Agrichemical Age, pp. 6-8, June 1973.

64.  Collins, Tom., Soil  Scientist, USDA Forest Service, Juneau, Alaska,
     personal communication, May 28, 1974.

65.  Warrington, Gordon, Soil  Scientist, USDA Forest Service, Sandpoint,
     Idaho, personal communication, May 29, 1974.

66.  Dyrness, C. T., Stabilization of Newly Constructed Road Backslopes by
     Mulch and Grass-Legume Treatments, USDA Forest Service, Pacific North-
     west Forest and Range Experiment Station Research Note PNW-123,
     July 1970.

67.  Wollum II, A. G., Grass Seeding as a Control for Roadbank Erosion, USDA
     Forest Service, Pacific Northwest Forest and Range Experiment Station,
     Research Note 218, June 1962.
                                   306

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                            REFERENCES (Cont'dr)
Text
No.

68.  Wilson, Carl N., Grass Seeding for Erosion Control in Southeast
     Alaska, U.S.D.A. Forest Service, Alaska Region, December 1965.

69.  Soil Conservation Service, Alaska Agricultural Experiment Station,
     University of Alaska Cooperative Extension Service, Grasses for
     Alaska, 197?.

70.  Turelle, Joseph W., "Factors Involved in the Use of Herbaceous
     Plants for Erosion Control on Roadways," Soil Erosion:  Causes and
     Mechanisms, Prevention and Control, Highway Research Board, National
     Research Council, National Academy of Sciences, National Academy of
     Engineering, Washington, D.C., Special Report 135, pp. 99-104,  1973.

71.  Plass, W. T., Chemical Soil Stabilizers for Surface Mine Reclamation,
     Highway Research Board Special Report 135, 1973. '

72.  Bethlahmy, N., and W. J. Kidd, Jr., Controlling Soil Movement from
     Steep Road Fill, U. S. Forest Service Research Note INT-45, 1966.

73.  Meyer, L.D., C.B. Johnson, and G.R. Foster, Stone and Woodchip Mulches
     for Erosion Control on Construction Sites, Journal of Soil and Water
     Conservation, Nov.-Dec. 1972.

74.  Barnett, A.P., E.G. Diseker, and E.G. Richardson, Evaluation of Mulch-
     ing Methods for Erosion Control on Newly Prepared and Seeded Highways
     Slopes, Agron, Journ. 59:83-85, 1967.

75.  Heath, Maurice E., Sheldon W. Carey, and H.D. Hughes, Sow Down the
     Highways, Farm Science Reporter.  6:7-10.  Ames,' Iowa, 1945.

76.  Diseker, E. G., E.G. Richardson, Highway Erosion Research Studies, 20th
     Short Course on Roadside Development, Ohio State University, Columbus,
     Ohio, 1961.

77.  Blaser, R.E., G.W. Thomas, C.R. Brooks, G.J.  Shoop, and J.B. Martin,
     Jr., Turf Establishment and Maintenance Along Highway Cuts, Roadside
     Development,  Highway Research Board, National Academy of Sciences-
     National Research Council, Publication No. 928, 5-19, 1961.

78.  Goss, R.L., R.M. Blanchard, and W.R. Melton,  the Establishment of
     Vegetation on Non-Topsoiled Highway Slopes in Washington,  Final Report,
     Research Project Y-1009, Washington State Highway Commission and
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     with Federal Highway Administration, Nov. 1970.
                                   307

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                          REFERENCES (Cont'd.)
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No.

79.   Washington State Department of Highways, Erosion Control:  State
      of the Science in Washington, undated.

80.   Crabtree, Robert J., Effectiveness of Different Types of Mulches
      in Controlling Erosion on Highway Backslopes, Unpubl. Master's
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81.   Swansnn, N.P., A.R. Dedrick, and A.E. Dedeck, Protecting Steep
      Construction Slopes Against Water Erosion, Highway Research Record
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82.   Whalen, Ken., Washington State Department of Highways, District 7,
      Personal communication, June 1974.

83.   Teng, Wayne C., Foundation Design, Prentice-Hall, Inc., 1962.

84.   Tschebotarioff, Gregory?., Soil Mechanics, Foundations, and Earth
      Structures, McGraw-Hill Book Co., Ind., 1951.

85.   Zaruba, Quido and Vg tech Mencl, Landslides and Their Control,
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86.   U.S. Department of Commerce, Bureau of Public Roads, "Design Charts
      for Open-Channel Flow", 1961, Superintendent of Documents, U. S.
      Government Printing Office, 105 pages.

87.   "Handbook of Steel Drainage and Highway Construction Products,"
      Highway Task Force for Committee of Galvanized Sheet Producers,
      Committee of Hot Rolled and Cold Rolled Sheet and Strip Producers,
      348 pages, 1971.

88.   "Hydraulic Charts for the Selection of Highway Culverts" reprint of
      Hydraulic Engineering Circular No. 5, U. S. Department of Commerce,
      Bureau of Public Roads, 44 pages, 1964.

89.   "Design Manual - Concrete Pipe".  American Concrete Pipe Association,
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90.   U. S. Department of Transportation, Federal Highway Administration,
      Bureau of Public Roads, Hydraulic Design Series No. 1 "Hydraulics of
      Bridge Waterways", 1970, Superintendent of Documents, U. S. Govern-
      ment Printing Office, Washington, D.C.
                                   308

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                           REFERENCES (Cont'd.)
 Text
 No.

 91.   "Design Charts for Open Channel Flow," U.S. Department of Commerce,
       Bureau of Public Roads, 105 pages, 1961.

 92.   "Design of Roadside Drainage Channels," U.S. Department of Commerce,
       Bureau of Public Roads, 56 pages, 1965.

 93.   Leydeeker, Allen D., Civil Engineer, Modoc National Forest, California
       "Use of Gabions For Low Water Crossings on Primitive or Secondary
       Forest Roads", U.S. Government Printing Office, 1973, 4 pages.

 94.   United States Steel Corporation, Bridge Structural Report "Nine Steel
       Bridges for Forest Development Roads South Tongass National Forest
       Alaska".  ADUSS 88-5973-01, 12 pages, June, 1973.

 95.   Rothacher, Jack S.  "Regimes of Stream Flow and Their Modification
       By Logging", Proceedings of A Symposium on Forest Land Uses and
       Stream Environment, Oregon State University, August 1971.

 96.   Harr, Dennis R., et al "Changes in Storm Hydrographs After Road Build-
       ing and Clear Cutting in the Oregon Coast Range", Unpublished Paper,
       1974, 35 pages.

 97.   Bethlahmy, Nedavia.  "Hydrologic Analysis Using the Arctangent Trans-
       formation".  Manuscript on file at Intermountain Forest and Range
       Experiment Station, U.S.D.A., Moscow, Idaho.  1974.

 98.   Bethlahmy, Nedavia.  Comments on "Effects of Forest Clear-felling on
       the Storm Hydrograph".  Water Resources Research 8(1): 166-170.

 99.   Dorroh, J. E., Jr., Certain Hydrologic and Climatic Characteristics
       of the Southwest, Univ. New Mexico Publ. Eng., 1, 64 pp., 1946.

100.   Croft, A.  R., and Richard B. Marston, Summer rainfall characteristics
       in northern Utah, Trans. Am. Geophys, Union, 31, 83-93, 1950.

101.   Sporns, U., On the transposition of short duration rainfall intensity
       data in mountainous regions, Arch. Meteor. Geophys. Biokl., 13B,
       438-442, 1964.

102.   Schermerhorn, Vail P., Relations between Topography and Annual Pre-
       cipitation in Western Oregon and Washington, Water Resources Research,
       Vol 3, No. 3, Third Quarter, 1967.
                                    309

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                         REFERENCES (Gont'd.)
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103.   Cooper, Charles F., Rainfall Intensity and Elevation in South-
       western Idaho, Water Resources Research,  Vol. 3, No. 1, First
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104-.   U. S. Environmental Protection Agency.  Proposed Water Quality
       Criteria.  Volume I.  Office of Water Programs, Washington, D.C.
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105.   Chevron Research Company.  "Analysis of the margin of safety
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       ing water reservoirs."  Richmond, California.  Unpublished.
       1974.

106.   Nielson, Lyman J., D. W. Schultz and R. B. Martson.  "Water
       solubles removed from surfaces stabilized with emulsified as-
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       300.  1969.

107.   Freestone, F. J.  "Runoff of oils from rural roads treated to
       suppress dust."  National Environmental Research Center, U. S.
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108.   Federal Water Pollution Control Administration.  Report of the
       Committee on Water Quality Criteria.  U. S. Department of the
       Interior, Washington, D.C.1968.

109.   Burger, Kenneth E.  "Toxicity of PS-300 On Juvenile Coho Salmon."
       Unpublished.  M.S. Thesis.  Humboldt State University, Arcata,
       California.  1973.

110.   American Public Health Association, American Water Works Associa-
       tion and Water Pollution Control Federation.  Standard Methods
       for the Examination of Water and Wastewater, 13th Edition.
       American Public Health, Washington, D.C.  1971.

111.   Braus, H., F. M. Middleton and G. Walton.  "Organic chemicals in
       raw and filtered surface waters."  Anal. Chem.  1951.  23: 1160-
       1164.
                                    310

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                         REFERENCES (Cont'd.)
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No.
112.   Middleton, F. M.  "Determination and Measurement of Organic
       Chemicals in Water and Waste."  Robert A. Taft Sanitary Engineer-
       ing Center, Technical Report W 612, Cincinnati.  1961.

113.   Environmental Protection Agency.  "Environmental Impact of High-
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114.   Wright, D. R.  "Dust control on all weather haul roads using
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115.   Cooper, G. R. and B. Heap.  "Sodium ion in drinking water."
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117.   Public Health Service Drinking Water Standards.  Public Health
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118.   Weigle, J. M.  "Groundwater contamination by highway salting."
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120.   Richardson, D. L.; Terry, R. C.; Metzger, J. B.; and Carroll,
       R. C.  Manual For Deicing Chemicals; Application Practices, En-
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121.   Richardson, D. L.; Campbell, C. P.; Carroll, R. J.; Hellstrom,
       D. I.; Metzger, J. B.; O'Brien, P. J.; Terry, R. C.  Manual for
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                                    311

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123.    Pearl, I. A. "Utilization of By-Products of the Pulp and Paper
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126.    Personal communication with Robert Strombom, USFS., Portland,
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127.    Department of Highways, Saskatchewan, Canada.  "Evaluation of
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        193:  8-21.
                                    312

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BIBLIOGRAPHIC DATA
SHEET
                     1.  Reoort No.
Keoort No.
EPA 910/9-75-007
        3. Recipient's Accession No.
4. Title and Subtitle

   LOGGING ROADS AND PROTECTION OF  WATER QUALITY
                                              5. Report Date
                                                 MARCH 1975
                                                                    6.
7. Author(s)
   EPA, REGION X; ARNOLD & ARNOLD AND  DAMES & MOORE. SEATTLE,  WA
                                              8. Performing Organization Rept.
                                                No-    N/A
9. Performing Organization Name and Address
   PART I:   PART  II PP 273-300
   U.S. ENVIRONMENTAL PROTECTION AGENCY
   1200 SIXTH AVENUE
   SEATTLE. WA  98101	
                                              10. Project/Task/Work Unit No.
                     PART  II  PP  91-272
                     ARNOLD & ARNOLD
                     1216  PINE STREET
                     SEATTLE.  WA  98101
        11. Contract/Grant No.
12. Sponsoring Organization Name and Address
   U.S.  ENVIRONMENTAL  PROTECTION AGENCY
   WATER DIVISION
   1200  SIXTH AVENUE
   SEATTLE, WA  98101
                                              13. Type of Report & Period
                                                Covered
                                                     FINAL
                                              14.
 15. supplementary Notes THE  ARNOLD AND ARNOLD  PORTION OF THE REPORT WAS PREPARED  UNDER EPA
  CONTRACT #68-01-2277.   DAMES & MOORE,  SEATTLE, WASHINGTON,  WERE SUB-CONSULTANTS
  FOR ARNOI H AND ARNOI n
16. Abstracts   THIS REpORT  Is A STATE-OF-THE  ART REFERENCE OF  METHODS, PROCEDURES  AND
   PRACTICES FOR INCLUDING WATER QUALITY CONSIDERATION IN THE  PLANNING, DESIGN,
   CONSTRUCTION, RECONSTRUCTION, USE AND MAINTENANCE OF LOGGING ROADS.  MOST OF  THE
   METHODOLOGY ALSO  IS APPLICABLE TO OTHER FOREST MANAGEMENT ROADS.  THE REPORT  IS
   DIVIDED INTO TWO  PARTS.  THE FIRST PART PROVIDES GENERAL PERSPECTIVE ON PHYSICAL
   FEATURES AND CONDITIONS IN EPA REGION X WHICH ARE RELEVANT  TO WATER QUALITY  PRO-
   TECTION AND LOGGING ROADS.  THE SECOND  PART OUTLINES SPECIFIC METHODS, PROCEDURES,
   CRITERIA AND ALTERNATIVES FOR REDUCING  THE DEGRADATION OF WATER QUALITY.  TOPIC
   COVERAGE IN THIS  PART  INCLUDES ROAD PLANNING, DESIGN, CONSTRUCTION AND MAINTENANCE
   INCLUDING THE USE OF CHEMICALS ON ROADS.   SILVICULTURAL ACTIVITIES ARE ONE CATEGORY
   OF  WATER POLLUTION FROM NONPOINT SOURCES  DESCRIBED IN PUBLIC LAW 92-500.  OF  ALL
   SILVICULTURAL ACTIVITIES,  LOGGING ROADS HAVE BEEN IDENTIFIED AS THE PRINCIPAL
   SOURCE  OF MAN-CAUSED SEDIMENT.
17. Key Words and Document Analysis.  17a. Descriptors
  LOGGING  ROADS
  FOREST ROADS
  FOREST MANAGEMENT ROADS
  WATER MANAGEMENT:ROADS
       WATER QUALITY  PROTECTION
       FOREST ROAD  CHEMICALS
       LOGGING ROAD CHEMICALS
       NONPOINT SOURCE
NONPOINT  SOURCE POLLUTION
SILVICULTURAL ACTIVITIES
WOODLAND  ROADS
17b. Identifiers/Open-Ended Terms
  METHODS,  PROCEDURES, PRACTICES  FOR REDUCING WATER QUALITY DEGRADATION
  FROM LOGGING  ROADS AND OTHER  FOREST ROADS.
  WATER QUALITY CONSIDERATIONS  IN LOGGING ROAD  PLANNING, DESIGN, CONSTRUCTION
  AND MAINTENANCE.
  IMPACTS OF  LOGGING ROADS AND  OTHER FOREST ROADS  ON WATER QUALITY
  WATER POLLUTION ABATEMENT FROM  NONPOINT SOURCES,  LOGGING ROADS AND  OTHER FOREST ROADS
                       ROADS AND OTHER FOREST ROADS  TO INCLUDE WATER QUALITY MANAGEMENT. "
18. Availability Statement

   RELEASE UNLIMITED
                                  19. Security Class (This
                                    Report)
                                       UNCLASSIFIED
                                                             ~».~.^.-^^^ ~^.u
                                                        20. Security Class (This
                                                           Page
                                                             UNCLASSIFIED
                  21. No. of Pages
                                                       22. Price
FORM NTis-35 (REV. 10-73)  ENDORSED BY ANSI AND UNESCO.
                                                  THIS FORM MAY BE REPRODUCED
                                                                              USCOMM-DC 8265-P74
                             U S. GOVERNMENT PRINTING OFFICE 1975-698-389/136 REGION 10

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