EPA 440/3-78-003
EROSION AND SEDIMENT
CONTROL HANDBOOK
^r t *
(
May 1978
DEPARTMENT OF CONSERVATION
Resources Agency
STATE OF CALIFORNIA
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p I
Land is California''!
most vital
and
most unrenewable resource.
In its use and misuse
rests the future of a great state
and
a great people.
Summary of ProceedingsGovernor's
Conference on California If Changing Environment
November 17-18, 1969, Los Angeles, California
Dnt Cover . ^DA Soil Conservotion 5er
Inside Cover Co. T Division of Resource Conse-varion
Los An_ Department of County Engineer,
Los Angeles -*
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EPA 440/3-78-003
EROSION AND SEDIMENT
CONTROL HANDBOOK
PERRY Y. AMIMOTO, ENGINEERING GEOLOGIST
DIVISION OF MINES AND GEOLOGY
Department of Conservation
The handbook was prepared under the direction of the Department of Conservation with the concurrence
of the California Association of Resource Conservation Districts and County Supervisors Association
of California and in consultation with the Environmental Quality Committee of the County Engineers
Association. It was published with the financial assistance provided by the U.S. Environmental Protection
Agency, Water Planning Division, Washington^ D.C.
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FOREWORD
Recent concern about the environment has focused attention on the effects of erosion and sediment runoff.
Together, these phenomena have diverse and widespread environmental impact. This impact in California is
documented in a report by the Division of Resource Conservation entitled "Environmental Impact of Urbani-
zation on Foothill and Mountainous Lands in California, November 1971". The report emphasizes the
increasing need to give more consideration to erosion and sediment problems as California's urbanization
moves into additional land areas. It also calls attention to the fact that sediment is, by volume, the largest single
water pollutant.
Adequate erosion control ordinances and other regulatory and contractual constraints along with the
installation and maintenance of effective erosion and sediment control measures are necessary to minimize
Adverse environmental impacts and damages resulting from accelerated erosion and deposition of excess
sediment loads.
As local governing agencies in California are the entities which have the authority to manage development
in such a way as to minimize erosion and sediment problems, the concept of providing these agencies with
technical assistance through an erosion control handbook evolved.
The handbook will provide a tool for the daily work of those in local government, and others, responsible
for assuring that development proceeds in such a manner as to have minimum adverse impact on the quality
of California's environment.
in
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CONTENTS
ACKNOWLEDGEMENT Inside Back Cover
FOREWORD HI
INTRODUCTION 1
MODEL EROSION CONTROL ORDINANCE 2
ARTICLE I TITLE, PURPOSE, AND GENERAL PROVISIONS 3
ARTICLE II PROCEDURE 4
ARTICLE III CONTENT OF EROSION AND SEDIMENT CONTROL PLANS 6
ARTICLE IV STANDARDS 9
ARTICLE V IMPLEMENTATION 12
ASSESSMENT OF NEED FOR EROSION AND SEDIMENT CONTROL 19
DESCRIPTION OF EROSION AND SEDIMENT CONTROL PRACTICES 25
SECTION 10. TREE PROTECTION 27
11.00 Damaging Construction Activities
12.00 Determining Which Trees are to be Removed
13.00 Required Practices During Construction
SECTION 20. ESTABLISHMENT OF PROTECTIVE VEGETATION 31
21.00 Grass, Legumes, Shrubs
21.10 Plant Characteristics
21.20 Fire Hazardous Plants
21.30 Regional Guide for Grass, Legumes, Shrubs
21.40 Shrubs for the Lake Tahoe Area and
Other Regions with Similar Climatic Conditions
21.50 Legume Innoculation by the U.C. Pellet Method
21.60 Common and Scientific Names of Plants
22.00 Seeding Methods
22.10 Ground Preparation
22.20 Manual Broadcasting
22.30 Drilling
22.40 Hydroseeding/Hydromulching
22.50 Spot Seeding of Shrubs
23.00 Stepping of Cut Slopes
24.00 Topsoil Specification
25.00 Planting Period and Irrigation Criteria
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SECTION 30. SURFACE PROTECTION WITH MULCHES AND OTHER MATERIALS 63
31.00 Purpose
32.00 Mulch Quality for Establishing Vegetation
33.00 Factors Affecting Effectiveness of Mulches
34.00 Control of Wind Erosion
35.00 List of Protective Coverings and Mulches
35.01 Plastic Sheet
35.02 Straw and Hay
35.03 Wood Chips and Sawdust
35.04 Gravel and Stone
35.05 Mulch Blanket
35.06 Wood Fiber
35.07 Washed Dairy Waste
35.08 Chemical Mulch
35.09 Wood Excelsior
35.10 Fiberglass
35.11 Jute
35.12 Sod
35.13 Building Block
SECTION 40. PROTECTION OF SLOPES AND OTHER GRADED AREAS FROM
RUNOFF 85
41.00 Temporary Diversion Dike
42.00 Permanent Diversion Dike
43.00 Interceptor Ditch
44.00 Slope Drain
44.10 Flexible Down Drain
44.20 Pipe Drop
44.30 Chute (Flume)
45.00 Diversion
SECTION 50. ROADWAY PROTECTION 103
51.00 Intercepter Dike
52.00 Drainage Dip
53.00 Side Ditch
53.10 Lined Side Ditch
53.20 Unlined Side Ditch
54.00 Open-Top Culvert
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SECTION 60. CHANNEL PROTECTION : 113
61.00 Vegetative Lining
61.10 Grass Lining
61.20 Lining with Woody Plants
62.00 Flexible Lining
62.10 Rock Lining
62.20 Gabions
62.30 Old Tires
63.00 Rigid Linings
SECTION 70. GRADE CONTROL AND REALIGNMENT OF CHANNELS 123
71.00 Channel Grade Control
71.10 Check Dams
71.20 Drop Structures
71.30 Erosion Stop
72.00 Channel Realignment
SECTION 80. INSTALLATION OF CULVERTS, PAVED FORDS, BRIDGES 131
81.00 Culverts
81.10 Design Considerations
81.20 Culvert Alignment
81.30 Culvert Grade
81.40 Culvert Capacity
81.50 Debris Control Device
81.60 Culvert Riser
81.70 Drop Inlet
81.80 Discharge Apron
81.90 Open-Top Culvert
82.00 Paved Fords
83.00 Bridges
SECTION 90. SEDIMENT TRAPS AND DETENTION BASINS 149
91.00 Sediment Traps
91.10 Filter Berm
91.20 Sandbag or Straw Bale Barriers
91.30 Filter Inlet
91.40 Vegetative Filter Strip
91.50 Culvert Riser
Vll
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92.00 Sediment Detention Basin
92.10 Design Considerations
92.11 Storage
92.12 Pipe Spillway
92.13 Emergency Spillway
92.14 Freeboard
92.15 Embankment
92.20 Construction
92.21 Site Preparation
92.22 Borrow Areas
92.23 Embankment
92.24 Pipe Spillway
92.25 Vegetative Protection
92.26 Protection of Spillway Discharge Area
92.30 Sediment Cleanout and Disposal
SECTION 100. DISSIPATING THE ENERGY OF RUNOFF WATER 163
101.00 Level Spreader
102.00 Hydraulic Jump
103.00 Discharge Aprons
104.00 Drop Inlet
GLOSSARY 168
BIBLIOGRAPHY 173
PHYSICAL AND CLIMATIC FACTORS 177
APPENDIX I ESTIMATING EROSION AND SEDIMENT LOSSES 179
A. Summary of Methods in Appendix I for
Computing the Rate of Erosion and
Sediment Yield
B. Sheet Erosion Computation
C. Roadway Erosion Computation
D. Downstream Sediment Delivery Computation
APPENDIX II CLIMATE, RUNOFF, ALLOWABLE VELOCITIES 189
A. Estimating Start and End of Rainy Period
B. Freeze-Free Chart
C. Determining Rate of Rainfall Runoff
D. Allowable Velocities for Unlined Earth Channels
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LIST OF FIGURES
Figure 1. Development approval process using a Model Erosion Control Ordinance 1
Figure 2. Pictorial map of development plan showing erosion and sediment control measures. [48]... 13
Figure 3. Examples of providing proper drainage location. [50] 13
Figure 4. Protective fencing. [57] 30
Figure 5. Tree protection by subdrainage structures. [57] 30
Figure 6. Tunneling vs. trenching. [57] 30
Figure 7. Location map for Regional Guide for Grass, Legumes, Shrubs 35
Figure 8. Planting seeds in a seed spot basin provides for proper fertilizer placement, seeding depth,
and moisture accumulation. [34] 51
Figure 9. Approximate number of seeds to plant in each seed spot depending on seed size and germina-
bility under non-irrigated conditions. [34] 51
Figure 10. A pocket formed in the slope helps to accumulate water near the seeding spot and to prevent
loose soil above from covering the spot. [34] 51
Figure 11. Sheet mulch on soil surface with opening over seed spot for weed control and reduction of
evaporation from the soil. [34] 52
Figure 12. Two methods of planting seeds in a collar to hasten germination and control weeds. [34]... 52
Figure 13. Typical section for serrated stepped slopes in soft rock. [61] 58
Figure 14. Rounded cut faces on serrated slopes 58
Figure 15. Detail for stabilizing waterway with jute thatching. [21] 80
Figure 16. Temporary diversion dike. [41] 88
Figure 17. Flexible downdrain. [57] 93
Figure 18. Pipe drop. [21] 94
Figure 19. Chute (flume). [41] 97
Figure 20. Diversion 101
Figure 21. Interceptor dike. [41] 105
Figure 22. Drainage dip. [29] 107
Figure 23. Drainage dip (profile). [29] 108
Figure 24. Culvert alignment. [29] 135
Figure 25. Guidelines on culvert grades. [29] 136
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Figure 26. Additional guidelines for culverts under fills. [29] [[[ 137
Figure 27. Entrance head vs. flood stage. [32] [[[ 138
Figure 28. Culvert riser. [31] [[[ 139
Figure 29. Drop inlet. [29] [[[ 14°
Figure 30. Discharge aprons [[[ 14^
Figure 31. Open-top box culvert. [29] [[[ 144
Figure 32. Paved ford. [29] [[[ 147
Figure 33. Filter berm. [57] [[[ 151
Figure 34. Temporary barrier of straw bales to prevent sediment-laden water from entering incomplete
storm sewer. [57]
Figure 35. Sand and gravel filter protecting intake area of incomplete storm sewer system. [56] .......... 157
Figure 36. Schematic design of sediment detention basins. [20] [56] [[[ 160
Figure 37. Level spreader. [22] [57] [[[ 166
Figure 38. Sediment predictive yeild. [8] [[[ 182
Figure 39. Road density and sediment production. [30] [[[ 184
Figure 40. Surface area of cut and fill per mile of road in acres. (Road width of 20 feet) .................... 185
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LIST OF TABLES
Table 1. Checklist for site evaluation 22
Table 2. Factors in the assessment of a site 23
Table 3. Relating sources of sediment or causes of accelerated erosion to erosion control practices . 24
Table 4. Regional guide for grass, legumes, shrubs for Region I - Central Valleys 36
Table 5. Regional guide for grass, legumes, shrubs for Region II-Foothills of the Sacramento Valley 37
Table 6. Regional guide for grass, legumes, shrubs for Region III-Central Coast and Foothills of the
San Joaquin Valley 38
Table 7. Regional guide for grass, legumes, shrubs for Region IV - Southern California 39
Table 8. Regional guide for grass, legumes, shrubs for Region V - North Coast 40
Table 9. Regional guide for grass, legumes, shrubs for Region VIHigh Elevationabove 3000 feet 41
Table 10. Regional guide for grass, legumes, shrubs for Region VII Desert 42
Table 11. Seed type vs. inoculant quantity. [58] 45
Table 12. Depth of seeding depression, soil depth over seed, and depth of depression for moisture for
various seed sizes. [34] 52
Table 13. Soil and chemical requirements. [42] 61
Table 14. List of protective coverings and mulches 66
Table 15. Effect of tackifier products on wind stability of barley straw. [17] 70
Table 16. Tests of wood fiber mulch conducted along California highways in the Lake Tahoe area. [15] 74
Table 17. Erosion control tests with chemical mulch and wood fiber. [16] 76
Table 18. Experimental tests of chemical mulches for control of wind erosion conducted by USD A,
Agricultural Research Service. [3] 76
Table 19. Dimensions for chute shown in Figure 19. [41] 98
Table 20. Spacing of checks in roadside ditches. [29] 112
Table 21. Cross-drain spacings for low to moderately steep topography. [29] 145
Table 22. Cross-drain spacings for very steep topography. [46] 145
Table 23. Design limitations and jurisdiction of dams in California. [39] 159
Table 24. Summary of methods in Appendix I for computing erosion and sediment yield 181
Table 25. Sediment yield computation using the PSIAC method. [24] 183
Table 26. Estimating start and end of rainy period 190
Table 27. Values of coefficient of runoff - "C". [25] 196
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LIST OF PHOTOS
Photo 1. Sediment and runoff control measures should have been provided along the subdivision road
(top photo) and ski slope (bottom slope). Top photo by California Department of Fish &
Game and bottom photo by Perry Y. Amimoto, California Division of Mines and Geology 14
Photo 2. Accelerated erosion occurred because the removal of vegetative cover was not followed by a
timely completion of proper grading operations. Photo by USDA Soil Conservation Service 15
Photo 3. An example of erosion of a steeply sloping fill in an area of steep topography (Lake Co.).
Photo by California Division of Resource Conservation ^
Photo 4. Deep erosion along an unlined interceptor ditch (Santa Cruz Co.). Photo by California
Division of Resource Conservation ^
Photo 5. The building of piers (right photo) for the new Auburn-Forest Hill Road Bridge across the
North Fork of the American River shows a poor construction practice (left photo) of dispos-
ing waste material by dumping it down the hill. Considerable fine-grained sediment was
transported downstream along the American River (Placer Co.). Photos by California Divi-
sion of Resource Conservation 16
Photo 6. This cleared vegetation is piled too close to adjacent trees thus risking fire and insect infesta-
tion (El Dorado Co.). Photo by California Division of Resource Conservation 17
Photo 7. A sudden rainfall would cause erosion and rapid downstream transport of this stockpiled
material (Lake Tahoe). Photo by Placer County Department of Public Works 17
Photo 8. Inspection of vegetated cut slope. Photo by USDA Soil Conservation Service 17
Photo 9. This subdivision road fill was seeded to intermediate wheatgrass, and the grass is effectively
stabilizing this roadside. Elevation is 7,000 feet, and the material is decomposed granite (El
Dorado Co.). Photo by USDA Soil Conservation Service 34
Photo 10. Digging holes for shrubs and trees for slope stabilization and beautification (San Joaquin
Co.). Photo by USDA Soil Conservation Service 45
Photo 11. Hydroseeding-hydromulching operations at Luther Pass in El Dorado County, Highway 89.
Photos by California Department of Transportation 49
Photo 12. Scarifying of cut slopes (180, Placer Co.). Photos by California Division of Resource Conser-
vation 55
Photo 13. Serrating of cut slopes (180, Applegate, Placer Co.). Top photos by California Division of
Resource Conservation and bottom photos by Perry Y. Amimoto, California Division of
Mines and Geology 56
Photo 14. This landsliding of a serrated cut slope occurred because the foundation material was
unstable serpentine (Lake Co.). Photo by Perry Y. Amimoto, California Division of Mines
and Geology ; 57
Photo 15. Topsoil placed on slopes along this freeway helped to produce the lush vegetation (Nevada
Co.). Top photo by USDA Soil Conservation Service and bottom photo by California
Division of Resource Conservation 60
Photo 16. Plastic sheets placed on road fill before paving prevented erosion (El Dorado Co.). Photo
by California Division of Resource Conservation 67
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Photo 17. Straw applied without anchoring. Photo by USDA Soil Conservation Service 69
Photo 18. Net-anchored straw. Photo by USDA Soil Conservation Service 69
Photo 19. Protection of cut slope using gravel (Humboldt Co.)- Photo by Perry Y. Amimoto, Califor-
nia Division of Mines and Geology 72
Photo 20. Woods excelsior covered with netting (Nevada Co.). Photos by Perry Y. Amimoto, Califor-
nia Division of Mines and Geology 77
Photo 21. Jute netting on cut slope (San Joaquin Co.). Photo by USDA Soil Conservation Service 79
Photo 22. Sodded storm drain. Photo by USDA Soil Conservation Service 82
Photo 23. Slope protection with building blocks placed in an attractive manner. Eventually, vegetation
will fill the space within the blocks as shown in lower photo. Top photo by USDA Soil
Conservation Service and bottom photo by Perry Y. Amimoto, California Division of Mines
and Geology (Los Angeles Co.) 83
Photo 24. Embankment erosion that would have been prevented by the use of diversion dikes (Yolo
Co.). Photo by Perry Y. Amimoto, California Division of Mines and Geology 87
Photo 25. The permanent dikes on each side of the road guide the runoff to a drain outlet (Placer Co.).
Photo by Placer County Department of Public Works 89
Photo 26. Erosion control of a cut slope by a lined interceptor ditch and revegetation (Nevada Co.).
Photo by California Division of Resource Conservation 90
Photo 27. Lack of a slope drain and an energy dissipator caused the erosion of this road fill (Humboldt
Co.). Photo by Perry Y. Amimoto, California Division of Mines and Geology 91
Photo 28. Slope drain (down drain) systems. Upper left photo shows intake to a pipe drop protected
by a sediment trap. Lower left photo shows erosion caused by poor design in which the flow
exceeded the capacity of the corrugated channel. Photo on right shows a temporary asphalt-
lined chute. Upper left photo and right photo by USDA Soil Conservation Service and lower
left photo by California Division of Resource Conservation 95
Photo 29. A metal chute (flume) protecting road fill. Photos by Perry Y. Amimoto and C. Forrest
Bacon, California Division of Mines and Geology (Siskiyou Co.) 96
Photo 30. Diversions should be constructed in the large graded area shown in the top photo and lined,
if necessary, as shown in the lower photo. Top photo by State Water Resources Control
Board and bottom photo by USDA Soil Conservation Service 100
Photo 31. Lined side ditches. Rock-lined hi upper photo and asphalt-lined in lower photo. Upper photo
by California Division of Resource Conservation and lower photo by USDA Soil Conserva-
tion Service 110
Photo 32. Erosion and sediment problems of unlined side ditches. Upper photo shows erosion along
the roadside, and the lower photo shows a culvert filled with sediment. Upper photo by
California Division of Resource Conservation and lower photo by USDA Soil Conservation
Service Ill
Photo 33. Grass-lined diversion terrace which prevents sediment from entering storm sewer. Photo by
USDA Soil Conservation Service , '. ; 115
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Photo 34. This channel is lined with grass on the left bank and with rock on the right bank. Photo by
USDA Soil Conservation Service 116
Photo 35. Gabion employed for slope protection (Mendocino Co.). Photo by Perry Y. Amimoto,
California Division of Mines and Geology
Photo 36. Old tires used for streambank protection. The lower photo shows how well vegetation has
grown within the tires. Photo by U.S. Bureau of Indian Affairs 120
Photo 37. Old tires lifted by A-frames and lowered onto the streambank. Photo by U.S. Bureau of
Indian Affairs 121
Photo 38. Check dams. Upper photo shows check dam in an unlined channel. Upper photo by Perry
Y. Amimoto, California Division of Mines and Geology and lower photo by USDA Soil
Conservation Service 126
Photo 39. Check dam constructed of concrete building blocks. Photo by USDA Soil Conservation
Service 127
Photo 40. Culvert pipe plugged with sediment causing overtopping and roadway washout (Siskiyou
Co.). Photo by C. Forrest Bacon, California Division of Mines and Geology. 134
Photo 41. Spillway of culvert lined with cemented rock (Yolo Co.). Photo by Perry Y. Amimoto,
California Division of Mines and Geology 138
Photo 42. A paved ford (Tulare Co.). Photo by Perry Y. Amimoto, California Division of Mines and
Geology 146
Photo 43. A pipe-arch bridge. Photo by California Department of Forestry 148
Photo 44. A sediment trap would have allowed this storm sewer system to collect runoff without
excessive sediment load. Photo by USDA Soil Conservation Service 155
Photo 45. Sediment detention basin. Photo by USDA Soil Conservation Service 158
Photo 46. Sediment detention basin used to protect the culvert and roadway (Tulare Co.). Photo by
Perry Y. Amimoto, California Division of Mines and Geology 161
Photo 47. A hydraulic jump-type energy dissipator device used to prevent erosion along a road drain-
age. Photo by California Division of Resource Conservation 167
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INTRODUCTION
This handbook provides the procedures by which
physical and climatic data and erosion control prac-
tices can be considered in making an assessment of
the site for determining the need for an erosion con-
trol plan and for preparing an erosion control plan.
Construction activities which require erosion control
plans include roads, large graded areas, waste dis-
posal sites, mine-land reclamation, logging, land-
slide mitigation, off-road vehicle sites, and ski
slopes.
The required content of an erosion and sediment
control plan is described in the chapter on the Model
Erosion Control Ordinance. Figure 1, Development
Approval Process using a Model Erosion Control
Ordinance, presents an orderly set of procedures that
serve both as a regulatory function in approving an
application for a proposed development and as a
means of applying the information in the chapter on
Erosion Control Practices.
ASSESSMENT
OF SITE
FOR EROSION
PROBLEMS
Figure 1. Development Approval Process Using a Model Erosion Control Ordinance.
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MODEL EROSION CONTROL ORDINANCE
ARTICLE I. TITLE, PURPOSE, AND
GENERAL PROVISIONS
101.00 Title
101.01 Purpose
101.02 Rules Applying to Text
101.03 Definitions
101.04 Appeals
101.05 Validity and Severability
101.06 Fees
101.07 Review and Approval
ARTICLE II. PROCEDURE
102.01 Grading Permit
102.011 Exceptions
102.02 Application for a Grading Permit
102.021 Site Map
102.022 Grading Plan
102.023 Assessment of the Site
102.024 Erosion and Sediment Control Plans
ARTICLE III. CONTENT OF EROSION
AND SEDIMENT CONTROL PLANS
103.01 Requirements
103.02 Protection of Native Vegetation
103.03 Removal of Native Vegetation
103.04 Establishment of Vegetation
103.05 Drainageway Protection and Control Measures
103.06 Sediment Detention Measures
103.07 Fill Slopes
103.08 Cut Slopes
103.09 Disposal of Spoil Material
103.10 Stockpile
103.11 Dust Control
103.12 Construction Schedule
ARTICLE IV. STANDARDS
104.01 General
104.02 Sediment Control
104.03 Natural Vegetation
104.04 Grading Practices
104.05 Control of Runoff
104.06 Slope Construction
104.07 Slope Surface Stabilization
104.08 Grading
104.09 Protection of Watercourses
104.10 Disposal of Cleared Vegetation
104.11 Disposal of Excavated Materials
ARTICLE V. IMPLEMENTATION
105.01 Enforcement and Inspection
105.02 Authority and Responsibilities
105.03 Performance Bond
105.04 Penalties for Violations
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MODEL EROSION CONTROL ORDINANCE
ARTICLE I
TITLE, PURPOSE, AND GENERAL PROVISIONS
101.00 Title. This ordinance shall be known as
the "(City/County) Erosion Control Ordi-
nance."
101.01 Purpose. The purpose of this ordinance is
to control erosion and production of sedi-
ment, and related environmental damage by
establishing minimum standards and pro-
viding regulations for the construction and
maintenance of land fills, excavations, cut
and clearing of vegetation, revegetation of
cleared areas, drainage control, as well as
for the protection of exposed soil surfaces in
order to promote the safety, public health,
convenience, and general welfare of the
community.
101.02 Rules Applying to Text. For the purpose
of this ordinance, certain rules of word us-
age apply to the text as follows:
1. Words used in the present tense include
the future tense, and the singular in-
cludes the plural unless the context
clearly indicates the contrary.
2. The term "shall" is always mandatory
and not discretionary; the word "may"
is permissive.
3. The word or term not interpreted or
defined by this article shall be used
with a meaning of common or standard
utilization.
101.03 Definitions. The definitions as stated in
the "GLOSSARY" of the EROSION AND
SEDIMENT CONTROL HANDBOOK
maintained by the permit-issuing authority
shall apply to the interpretation and en-
forcement of this ordinance.
101.04 Appeals. Appeals from decisions under
this ordinance may be made to the permit-
issuing authority in writing within ten days
from the date of such decision. The appel-
lant shall be entitled to a hearing before the
permit-issuing authority within thirty days
from the date of appeal.
101.05 Validity and Severability. If any part of
this ordinance is found not valid, the re-
mainder of this ordinance shall remain in
effect.
101.06 Fees. A schedule of reasonable fees shall
be established that will reimburse the per-
mit-issuing authority for costs incurred in
the review and approval of the application.
101.07 Review and Approval. Applications for
grading permits shall be reviewed by the
permit-issuing authority and approved
when in conformance with this ordinance.
References used: [10][22][44][47][57] Bibliography of Erosion
and Sediment Control Handbook. j
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ARTICLE II
PROCEDURE
102.01 Grading Permit. Except as indicated be-
low, no person shall commence or perform
any grading or filling or clearing of vegeta-
tion without having first obtained a grad-
ing permit from the permit-issuing
authority.
102.011 Exceptions. A permit shall not be re-
quired if the work meets any of the follow-
ing conditions:
1. The excavation does not exceed four
(4) feet in vertical depth at its deepest
point, measured from the original sur-
face, and does not exceed 200 square
feet in area.
2. The fill does not exceed three feet in
vertical height at its highest point,
measured from the natural ground
surface, and does not cover more than
200 square feet.
3. Exploratory excavations do not ex-
ceed an aggregate area of 200 square
feet.
4. An excavation below finished grade
for basements and footings of a build-
ing if authorized by a valid building
permit. This exception does not affect
the requirement of a grading permit
for any fill made with the material
from such excavation.
5. Clearing of vegetation does not exceed
1,000 square feet in area.
6. Use of land is for gardening primarily
for home consumption.
7. Agricultural use of land that is oper-
ated in accordance with a farm con-
servation plan approved by the
Resource Conservation District or
when it is determined by the Resource
Conservation District that such use
will not cause excessive erosion or
sediment losses.
102.02 Application for a Grading Permit. The ap-
plication for a grading permit shall in-
clude:
1. a site map.
102.021
2. a grading plan.
3. an assessment of the site.
4. an erosion and sediment control plan
except where an assessment of the site
shows that a plan is not necessary.
Site Map. The site map shall include the
following:
1. The exterior boundaries of the prop-
erty on which the grading is to be per-
formed.
2. Contour line which shall conform to
minimum intervals as follows:
a. 2-foot contours for slopes less
than 16%.
b. 5-foot contours for slopes over
16%.
c. 15-foot contours for topography
of adjacent areas.
3. Soil description including:
a. soil type
b. soil depth
c. erodibility
d. capability for establishing vegeta-
tion.
e. coefficient of runoff. (Appendix
11C, Determining Rate of Rain-
fall runoff.)*
4. Evaluation of subsurface information
(as described in part 5 below) where
the stability will be lessened by
proposed grading or filling, or where
any of the following conditions are
discovered or proposed:
a.
At locations where a fill slope is to
be placed above a cut slope.
"References are to permit-issuing authority's Erosion and Sedi-
ment Control Handbook
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b. At proposed cuts exceeding
twenty feet in height unless in
competent rock as determined by
an engineering geologist.
c. Locations of proposed fills ex-
ceeding twenty feet in height.
d. Where side hill fills are to be
placed on existing slopes steeper
than 16%.
e. Wherever groundwater from ei-
ther the grading project or adjoin-
ing properties is likely to reduce
the stability.
f. At zones of trapped water or high
water table.
g. Where the topography is indica-
tive of landslides, as determined
by engineering geologist.
5. Where any of the particular condi-
tions listed above or other weaknesses
are found, subsurface investigations
shall consist of drilling, excavations,
or observations of naturally exposed
soil and bedrock exposures at suffi-
cient intervals and depths to indicate
the type of material or condition to be
encountered at final grading. The per-
son or firm making the investigation
shall submit a written report of their
findings and recommendations.
102.022 Grading Plan. The grading plan shall in-
clude the following information which
may be shown on the site map:
1. Elevations, dimensions, including
quantity, location, and extent of
proposed grading.
2. A report showing extent and manner
of tree cutting and vegetation clearing,
including a plan for disposing of cut
trees and vegetation.
3. Provision for stockpiling topsoil and
using it to topdress exposed areas to be
revegetated or a statement that this
provision is not applicable.
102.023 Assessment of the Site. The assessment
of the site shall determine the need for an
erosion and sediment control plan by con-
sidering the detrimental effects of con-
struction of the site as it pertains to:
1. erosion and loss of sediments
2. slope stability
3. water quality
4. plant communities
5. aquatic life
102.024 Erosion and Sediment Control Plans
1. The plan shall be prepared by a person
or firm qualified by training and expe-
rience to have expert knowledge of
erosion and sediment control meth-
ods.
2. The permit-issuing authority shall de-
termine the adequacy of the plan and
may require the submission of further
information when necessary to judge
the adequacy of the planned erosion
and sediment control measures.
3. Formulation of the implementation of
the proposed measures may be adopt-
ed from recommendations contained
in the permit-issuing authority's Ero-
sion and Sediment Control Hand-
book. The plan shall contain a
description of the following:
a. Vegetative measures
b. Drainage protection and control
measures
c. Erosion and sediment control
d. Cut and fill construction
e. Disposal of spoil materials
f. Stockpiling of materials
g. Dust control measures
h. A construction schedule
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ARTICLE III
CONTENT OF EROSION
AND SEDIMENT
CONTROL PLANS
103.01 Requirements. The erosion and sediment
control plan shall contain appropriate in-
formation according to this article. The
plan shall also conform to the requirements
in the sections on "Standards" and "Im-
plementation" of Articles IV and V, respec-
tively.
103.02 Protection of Native Vegetation. In order
to protect native vegetation from construc-
tion activities the following information
shall be provided:
1. Location of native vegetation whose
., root zone will be affected by compac-
tion, fills, trenches, and changes in the
groundwater table.
2. Measures which will prevent condi-
tions damaging to vegetation shall be
specified. (Section 10 - Tree Protec-
tion)*.
103.03 Removal of Native Vegetation. When na-
tive vegetation is to be removed, the follow-
ing information shall be provided:
1. Descriptions of the native vegetation.
2. A list of the vegetation to be removed
and the criteria used to determine re-
moval. (Section 10).
3. The methods for removing and dispos-
ing of the vegetation. (Section 10).
103.04 Establishment of Vegetation. Where the
establishment of vegetation is required on
slopes of cut and fill, graded areas, and
watercourses, the following information
shall be provided on the:
1. Location and area to be vegetated.
2. An indication of whether vegetation is
temporary or permanent.
* References are to permit-issuing authority's Erosion and Sedi-
ment Control Handbook
3. Type and quantity of seeds or plants.
(Section 20 - Establishment of Protec-
tive Vegetation).
4. Ground conditions:
a. Surface condition of soil.
b. Soil pH.
c. Permeability.
d. Soil size distribution.
e. Slope angle, slope length, and as-
pect.
f. Nutrients in soil
5. Type and quantity of mulch. (Section
30 - Surface Protection with Mulches
and Other Materials).
6. Type and quantity of fertilizer. (Sec-
tion 20).
7. Method and schedule of seeding,
mulching, planting, and fertilizing.
(Section 20).
8. Schedule of irrigation. (Section 20).
103.05 Drainageway Protection and Control
Measures. Where it is necessary to reduce
the increased rate and volume of rainfall
runoff due to the alteration of the runoff
pattern, the following data shall be pro-
vided:
1. The runoff to be expected during and
after the proposed development. (Ap-
pendix II - Climate, Runoff, Allowable
Velocities).
2. The location of natural and man-made
drainageways.
3. The size of drainage areas above cuts
and slopes.
-------
4. The methods to be used to reduce ero-
sion of drainageways. (Section 60 -
Channel Protection; Section 70 -
Grade Control and Realignment of
Channels).
5. The procedures used to trap sediment
in order to protect drainage control
measures. (Section 90 - Sediment
Traps and Detention Basins).
6. The methods to control the rate and
direction of runoff on roadways during
and after development. (Section 50 -
Roadway Protection).
7. The methods used to control runoff
across the slopes of cuts and fills and
graded areas during and after construc-
tion. (Section 40 - Protection of Slopes
and other Graded Areas from Runoff).
8. The construction schedule for drainage
protection and control measures. (Ar-
ticle III, 103.12 Construction Sched-
ule).
9. The method and schedule of construc-
tion of waterway crossings. (Section 80
- Installation of Culverts, Paved Fords,
Bridges).
103.06 Sediment Detention Measures. Informa-
tion on the design criteria of sediment ba-
sins shall include the following:
1. The location and dimensions of the
sediment basins. (Section 90).
2. The hydrologic and sediment transport
data used to determine the proper
capacity of the needed basin. (Appen-
dix I, Estimating Erosion and Sediment
Losses; Appendix II, Climate, Runoff,
Allowable Velocities).
3. The construction procedure and sched-
ule. (Section 90).
4. The source of borrow material.
5. The maintenance schedule.
6. The type and manner of vegetating the
erodible slopes as described in item
103.04, Establishment of Vegetation.
103.07 Fill Slopes. Where fill slopes are to be
constructed, the following information shall
be included:
1. Location of fill area.
2. Slope and height of fill.
3. Slope and condition of original
ground.
4. The number and dimensions of
benches.
5. Source of fill material.
6. Ability of fill to support vegetation.
7. Percent organic content of, fill.
8. Maximum size of rock in fill.
9. Maximum thickness of layers of fill to
be compacted.
10. Percent Compaction.
11. Methods of protecting the slope sur-
face of the fill.
12. Number and width of drainage ter-
races to be installed.
103.08 Cut Slopes. Where slopes are to be formed
from cuts, the following information shall
be included:
1. Location of cuts.
2. Slope and height of cuts. >
3. Identification of cuts to be vegetated or
not subject to erosion.
4. Number and width of drainage terraces
provided.
5. The ability of the ground to support
vegetation. (Section 20).
103.09 Disposal of Spoil Material. The informa-
tion concerning the disposal of spoil materi-
al shall include the following:
1. Type of spoil material.
2. Location of disposal area.
-------
3. Method of processing and disposing of
spoil material.
4. Procedures to prevent soil loss to adja-
cent watercourses.
5. Burning procedure for flammable spoil
material and its schedule.
103.10 Stockpile. Stockpiled material shall be
identified according to:
1. Source of material.
2. Location, slope, and height of stock-
pile.
3. Duration that the material is to be
stockpiled.
4. Provisions to prevent erosion and sedi-
ment loss from rain and wind action.
103.11 Dust Control. The following provisions
for dust control shall be included:
1. Measures to keep dust to a minimum
during equipment operation.
2. Measures to prevent wind erosion of
exposed soil. (Sections 20 and 30).
103.12 Construction Schedule. A construction
schedule shall be provided by the contrac-
tor. No work shall be permitted on the site
until the schedule has been approved in
writing by the permit-issuing authority.
The permit-issuing authority shall check
the adequacy of the schedule with respect to
the factors that could contribute to both
short-term and long-term erosion on the
project site.
The construction schedule shall be checked
for prompt establishment of protective
vegetation with full recognition of climatic
and other factors that influence its estab-
lishment.
-------
ARTICLE IV
STANDARDS
104.01 General. The grading plans and erosion
control plans shall conform to the standards
set forth in this Article.
104.02 Sediment Control.
1. Sediment shall be retained on the site.
(Section 90 - Sediment Traps and De-
tention Basins).*
2. Sediment basins, sediment traps, or
similar sediment control measures shall
be installed before extensive clearing
and grading operations begin.
104.03 Native Vegetation.
1. Native vegetation shall be retained,
protected, and supplemented wherever
possible. (Section 10 - Tree Protection;
Section 20 - Establishment of Protec-
tive Vegetation).
2. When vegetation must be removed, the
method shall be one that will minimize
the erosive effects from the removal.
(Section 10; Section 30 - Surface Pro-
tection with Mulches and Other
Materials).
3. Exposure of soil to erosion by removing
vegetation shall be limited to the area
required for immediate construction
operations.
104.04 Grading Practices.
1. Grading operations shall be conducted
so as to prevent damaging effects of
sediment production and dust on the
site and on adjoining properties.
2. In no event shall the native vegetative
ground cover be destroyed, removed,
or disturbed more than 15 days prior to
grading unless otherwise approved by
the engineer representing the permit-
issuing authority.
104.05 Control of Runoff.
1. Provisions shall be made to control the
increased runoff caused by changed soil
and surface conditions during and after
development. (Sections 40 through
100).
2, To prevent excess runoff the rate of sur-
face water runoff shall be structurally
retarded. (Sections 90 and 100).
3. Each applicant requesting permission
to make any surface changes shall be
required to:
a. Collect on-site surface runoff and
dispose of it at nonerosive velocities
to the point of discharge into the
common natural watercourse of
the drainage area.
b. Handle existing and potential off-
site runoff through his develop-
ment by designing to handle ade-
quately storm runoff from a fully
developed area upstream.
c. Pay his proportionate share of the
total cost of off-site erosion and
sediment control improvements to
the common natural watercourse,
based on a fully developed drainage
area.
d. Provide and install, at his expense,
ali drainage, erosion, and sediment
control practices (temporary and
permanent) required by the Ero-
sion and Sediment Control Hand-
book.
e.
* .References are to permit-issuing authority's Erosion and Sedi-
ment Control Handbook
Retain sediment being transported
by runoff water on-site through the
use of sediment basins, silt traps, or
similar measures.
4. Concentration of surface water runoff
shall only be permitted in swales or
watercourses.
-------
10
5. In order to prevent polluting discharges
from occurring, approved erosion and
sediment control devices shall be re-
quired for all grading and filling. Con-
trol devices and measures which may
be required include, but are not limited
to, the following:
a. Energy absorbing devices to reduce
the velocity of runoff water. (Sec-
tion 100 - Dissipating the Energy
of Runoff Water).
b. Sedimentation controls such as
sediment debris basins and sedi-
ment traps. Any trapped sediment
shall be removed to a disposal site
approved by the permit-issuing au-
thority. (Section 90).
c. Dispersal of water runoff from de-
veloped areas over large undis-
turbed areas.
d. Multiple discharge points to
reduce the volume of runoff over
localized areas.
104.06 Slope Construction
1. Slopes, both cut and fill, shall not be
steeper than 2:1 unless a thorough geo-
logical and engineering analysis indi-
cates that steeper slopes are safe and
erosion control measures are specified.
2. Slopes shall not be constructed so as to
endanger or disturb adjoining property.
104.07 Slope Surface Stabilization.
1. Temporary mulching, seeding, or other
suitable stabilization measures shall be
used to protect exposed critical areas
during construction or other land dis-
turbance. (Sections 20 and 30).
2. Earth or paved interceptors and diver-
sions shall be installed at the top of cut
or fill slopes where there is a potential
for surface runoff. (Section 40 - Pro-
tection of Slopes and Other Graded
Areas from Runoff).
104.08 Grading.
1. All land within a development shall be
graded to drain and dispose of surface
water without ponding, except where
approved by the permit-issuing author-
ity.
2. Where drainage swales are used to di-
vert surface waters, they shall be vege-
tated or protected as required. (Section
60 - Channel Protection)
104.09 Protection of Watercourses.
1. Fills shall not encroach on natural
watercourses or constructed channels.
2. Fills placed against watercourses shall
have suitable protection against erosion
during flooding.
3. Grading equipment shall not cross or
disturb live stream channels.
4. Excavated materials shall not be depos-
ited or stored in or alongside the river
or watercourses where the materials
can be washed away by high water or
storm runoff.
104.10 Disposal of Cleared Vegetation.
Vegetation removed during clearing opera-
tions shall be disposed of as follows:
1. Chipping all or some of the cleared
vegetation for use as mulch or compost
on the site. (Section 30).
2. Burning all or some of the cleared vege-
tation. Material to be burned shall be
piled in a manner and in such locations
as will cause the least fire risk and least
damage to adjacent trees by insect in-
festation.
3. Burning so thorough that the materials
are reduced to ashes. No logs,
branches, or charred pieces shall be
permitted to remain. Burning shall
comply with local air pollution regula-
tions.
-------
11
4.
Disposing the balance of the material in
a manner and at a location approved by
the permit-issuing authority.
104.11 Disposal of Excavated Materials. Ex-
cavated materials removed during grading
operations shall be disposed of as follows:
1. Stockpiling all or some of the topsoil on
the site for use on areas to be revegetat-
ed.
2. Locating stockpiled soil so that if ero-
sion occurs, it would not become a
source for off-site sediment damage.
3. Stockpiling soil far enough from
streams or drainageways that surface
runoff cannot carry sediment down-
stream.
4. Stockpiling material from trenches and
pits on the upslope side of the excava-
tions.
5. Promptly backfilling and compacting
stockpiled soil into trenches and pits to
reduce the risk of erosion.
6. Applying mulch or other protective
coverings on stockpiled material which
will be exposed through the winter sea-
son or which faces a high risk of inten-
sive summer rains. (Section 30).
7. Excavated material not to be used at
the site to a location approved by the
permit-issuing authority.
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12
ARTICLE V
IMPLEMENTATION
105.01 Enforcement and Inspection. The provi-
sions of this ordinance shall be enforced by
the permit-issuing authority who shall re-
view project plans and approve them if
found to be in compliance with the ordi-
nance, and by the engineer who shall in-
spect work and require compliance with all
the provisions of the ordinance.
105.02 Authority and Responsibilities. The con-
tractor shall install all soil erosion and sedi-
ment control measures in strict compliance
with the ordinance and in accordance with
the approved erosion control plan.
All soil erosion and sediment control meas-
ures shall be adequately maintained by the
contractor for a period of three years or
until such measures are stabilized as deter-
mined by the engineer.
Upon application by the contractor, the en-
gineer shall give the contractor a certificate
of completion indicating the date on which
the measures in the approved plan were
completed.
The engineer shall prohibit further work to
be done if it is determined by him that the
work does not comply with the provisions
of the approved erosion control plan or with
the provisions of the ordinance until such
time as compliance with the ordinance is
assured.
The engineer may allow a new or modified
erosion and sediment control technique to
be used provided there is mutual agreement
between the engineer and contractor that
the technique meets the intent of the erosion
control plan.
The engineer may cause remedial work to
be done if he determines that it is necessary
to protect completed work or to prevent
damage. The cost of such remedial work
shall be deducted from the amount due the
contractor under the terms of his contract.
105.03 Performance Bond. A performance bond
shall be posted by the contractor. The
amount of bond shall be the full cost of the
installed erosion and sediment control
measures. The bond shall not be released
until the erosion and sediment control
measures have performed satisfactorily as
determined by the engineer for a period of
three years. The bond may be used to pro-
vide for the installation of the control meas-
ures if not done by the contractor and
sediment runoff is occurring as a result.
105.04 Penalties for Violations. Penalties for viola-
tions of the ordinance may be assessed by
proper authority on recommendation of the
engineer. The kind of penalty and severity
of penalty shall be specified and may consist
of:
1. Fines
2. Stop orders
3. Corrective action order
END-
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13
Woods
Property linos
Storm drains
Sod waterways
100-year flood
plain limits
Streets
Diversion dikes
Debris basins
(Sediment basins)
Silt traps
Paved chutes
Figure 2. Pictorial Map of Development Plan Showing Erosion and Sediment Control Measures. [48]
Side Swale or Channel-
Rear Drainage Swale;
Protective Slopes -
Front Drainage Swale
Drainage Divide
Possible locations of rear drainage
easements to proper outfall
Drainage Divides-
Rear Slopes to
Drainage Easement
Rear Drainage Easement
to proper outfall
Protective Slopes-7 side Swale or Channel-
Rear Drainage Swales-
Figure 3. Examples of Providing Proper Drainage Location. [50]
-------
14
Photo 1. Sediment and Runoff Control Measures Should Have Been Provided Along the
Subdivision Road (Top Photo) and Ski Slope (Bottom Photo).
-------
USDA Soil Conservation Service
Photo 2. Accelerated Erosion Occurred Because the Removal of Vegetative Cover was not Followed by a Timely Completion of Proper
Grading Operations.
Photo 3. An Example of Erosion of a
Steeply Sloping Fill in an Area of Steep
Topography. (Lake Co.)
:' "V
California Division of Resource Conservation
-------
6
Photo 4. Deep Erosion Along an Unlined
Interceptor Ditch. (Santa Cruz Co.)
California Division of Resource Conservation
California Division of Resource Conservation
Photo 5. The Building of Piers (Right Photo) for the New Auburn-Forest Hill Road Bridge Across the North Fork of the American River Shows
a Poor Construction Practice (Left Photo) of Disposing Waste Material by Dumping it Down the Hill. Considerable Fine-Grained Sediment
was Transported Downstream Along the American River. (Placer Co.)
-------
Photo 6. This Cleared Vegetation is Piled
Too Close to Adjacent Trees Thus Risking
Fire and Insect Infestation. (El Dorado Co.)
California Division of Resource Conservation
Photo 7. A Sudden Rainfall Would Cause
Erosion and Rapid Downstream Transport of
This Stockpiled Material. (Lake Tahoe)
I
Placer County Department of Public Works
USDA Soil Conservation Service
Photo 8. Inspection of Vegetated Cut
Slope.
-------
19
ASSESSMENT OF NEED FOR
EROSION AND SEDIMENT CONTROL
-------
21
SELECTION OF EROSION AND
SEDIMENT CONTROL PRACTICES
The process for the selection of erosion control prac-
tices involves the following:
1. Answering the questions in Table I - Checklist
for site evaluation.
2. Considering the factors affecting accelerated
erosion in Table 2 - Factors in the assessment of
the site.
3. Selecting the temporary or permanent erosion
and sediment control practices as shown in Ta-
ble 3 - Relating sources of sediment or causes of
accelerated erosion to erosion control practices.
-------
22
Table 1. Checklist for Site Evaluation.
DEVELOPMENT SITE CONDITIONS
co
6-1
O
(B
PH
pi
K
H-
§
l-l
O
i-q
Pi
EH
P-i
1
MING OP DETEIMEHTAl EFFECTS
B
1. Are there areas where soil conditions indicate that
erosion is a possibility?
2. Will erosion occur as a result of any or all proposed
alternatives?
3. Will adjacent and nearby streams, ponds, and lakes be
affected by project construction?
4. Is there the potential for flooding in natural and
manmade waterways and' channels from the increased
runoff caused by changed soil and surface conditions?
5. Will the development disturb areas in or near stream
channels?
6. Do the proposed roads have long stretches of excessive
grade?
7. Will the drainage to streets and from streets to storm
sewers or other runoff disposal systems cause water to
erode the land or flood property further down gradient?
1. Can areas of exposed soil be protected from erosion
by the establishment of vegetative cover and by the
diversion of runoff?
2. Can sediment from construction activities be contained
on or near the project?
3. Will special erosion control and sediment collection
measures be required to protect adjacent properties?
4. Will construction sequence, method of operations or
season of work have an effect on control measures?
5. Does the adjoining property require special erosion
control or sediment collection methods?
6. Can lots be graded without mass grading techniques?
7. Are underground utilities provided for?
8. Can trees and other vegetation be protected?
9. Are paved and other impervious areas held to the
minimum?
10. Are onsite temporary storage of rainfall included?
11. Is fire protection included with sufficient and proper
ingress and egress?
12. Can the maintenance of all erosion control practices
be adequately provided?
13. Is the design storm frequency adequate?
14. Can vegetation be allowed to remain in some areas?
YES
NO
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23
Table 2. Factors in the Assessment of a Site.
List of Factors
Assessment of Impact
.of Factors on the Site
(Statement Heeded)
Soil and Geology
Soil - Physical & Chemical Character-
Geologic Conditions istics
Groundwater Occurrence & Movement
Slope stability
Seismic Factor
Climate and Precipitation
Start and End of Rainy Season
Intensity and Duration of Storms
Occurrence of Summer Storms
Seasonal Temperature
Frost-Free Period
Wind Erosion
Snow Melt Runoff
Rainfall Runoff Before and After
Development
Topography
Slope Angle
Slope Aspect
Slope Length
Density and Capacity of Drainageways
Suitability of Sites for Sediment
Basins
Vegetative Cover
Type and Location of Native Plants
Fire Hazard
Establishing Vegetative Cover
Adequacy of Existing Erosion Control
Features
Type of Development
Cluster or High Density Structures
Single Family or Low Density Structures
Percent Open Space and Impervious
Surfaces
Manner of Development
Percent Grade and Layout of Roads
Density of Roads
Distribution of Open Space
Structures Affecting Erodible
Areas
Number of Culverts, Stream Crossings
Size of areas, duration and time of
year that are left bare
-------
24
Table 3. Relating Sources of Sediment or Causes of Accelerated Erosion to Erosion Control Practices.
Section
10
20
30
40
50
60
70
80
90
100
^^Sources of Sediment or
^^Siijauses of Accelerated
^^»^^ Erosion
Erosion ^^^^^^
and Sediment ^^N*SiNl(|^
Control Practices ^^^^^
Protection of Trees
Vegetative Measure
Protective Covering of
Mulch and Other Materials
Temporary Diversion Dike
Permanent Diversion Dike
Interceptor Ditch
Slope Drain
Diversion
Interceptor Dike
Drainage Dip
Side Ditch
Op en- Top Culvert
Vegetative Lining
Flexible Lining
Rigid Lining
Grade Control Structure
Channel Realignment
Culvert
Paved Ford
Bridge
Sediment Trap
Sediment Detention Basin
Energy Dissipator
Loss ol
Trees
P
Bare
Cut and
Fill Slopes
and Graded
Areas
T,P
T
T
P
P
T,P
T,P
Unpro-
tected
Road
Surfaces
T
T
T
T
T,P
T,P
Sensi-
tive
Water-
courses
T,P
T
P
P
P
P
P
T,P
P
T,P
T,P
T,P
T,P
Hote:
T: temporary erosion control practices which would prevent
erosion during construction or before construction is
completed.
P: permanent erosion control practices which would permanently
stay on the project area for erosion control.
-------
25
DESCRIPTION OF EROSION
AND SEDIMENT CONTROL PRACTICES
-------
27
Section 10
PROTECTION OF TREES
-------
29
11.00 Damaging Construction Activities
1. Equipment impacting trunk, limbs, and
roots of trees.
2. Compacting soil over feeder roots.
3. Stockpiling of soil and .construction
material on root zone.
4. Installing structures which change
groundwater table.
5. Trenching across roots.
6. Improper selection of trees for removal.
12.00 Deterniining Which Trees are to be
Removed [41]
1. Trees with shallow root systems may
blow over easily if they have been grow-
ing in a close stand.
2. Trees which are sensitive to disease and
rot should be removed. Diseased and
damaged trees should be identified and
appropriately marked.
13.00 Required Practices During Construction
[211 [57]
1. Protective fencing or barriers erected
along drip line of tree (See Figure 4).
2. All tree limbs damaged during building
or land leveling, or removed for any
other reason, be sawed flush to tree
trunks and painted with a good grade
of "tree paint".
3. Tree trunks and exposed roots dam-
aged during equipment operations be
painted immediately with a good grade
of "tree paint".
4. Boards and signs not be nailed to trees
during building operations.
5. Care for serious injury be prescribed by
a forester or licensed tree expert.
6. If fill must be placed over root zone,
install porous zone for aeration. (See
Figure 5)
7. Tunneling be preferred over trenching.
(See Figure 6)
8. Avoid construction which changes the
groundwater table.
9. Diseased and damaged trees previously
identified be removed.
10. To decrease insect infestation, dust be
held to a minimum.
-------
30
Figure 4. Protective Fencing. [57]
tile and gravel will allow
air circulation to root zone under a fill
Figure 5. Tree Protection by Subdrainage Structures. [57]
trenching that would probably kill the tree
tunneling under tree will preserve
many of the important feeder roots
Figure 6. Tunneling vs. Trenching. [57]
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31
Section 20
ESTABLISHMENT OF PROTECTIVE VEGETATION
-------
33
21.00 GRASS, LEGUMES, SHRUBS
21.10 PLANT CHARACTERISTICS
1. The type of plants used in establishing
vegetative protection for erosion control
shall have the following characteristics:
a. Must be self-sustaining.
b. Require little or no maintenance.
c. Not increase the fire hazard.
2. The "Regional Guide for Grass,
Legumes, Shrubs", Section 21.30, lists
the type of vegetation which have the
above characteristics for use throughout
California.
3. Because of local variations in climate,
soils, and seed availability, it is recom-
mended that additional information be
obtained from on-site studies and from
agencies including the Resource Conser-
vation Districts and the County Engi-
neer.
21.20 FIRE HAZARDOUS PLANTS [9]
The use of fire hazardous plants for erosion
control purposes, particularly in developed
areas, shall be avoided. These plants which
are listed below are not included in the "Re-
gional Guide for Plants, Legumes, and
Shrubs".
1. Chamise (greasewood)
2. Sage (Salvia)
3. Blue Gum (Eucalyptus globulus)
4. Dwarf rosemary (Rosmarinus offici-
nalis prostrate)
5. Bamboo clumps (Bambusa, et at)
6. Cypress (Cupressus)
7. Laurel sumac
8. Sugar sumac
9. Lemonade berry sumac
10. Scrub oak
11. Toyon
12. Holly-leaved cherry
13. Cheat grass
21.30 REGIONAL GUIDE FOR GRASS,
LEGUMES, SHRUBS [13][28][36][43]
This section provides for determining exam-
ple types of vegetation that are suitable for
any area in the State of California. The pro-
cedure is as follows:
1. Locate the problem area in one of seven
regions (I to VII) as shown in Figure 7.
2. Refer to Tables 4 to 10 which describes
the type of vegetation, amount of seed,
and fertilizer for each region.
a. Compare seed mixtures, if required,
in relation to elevation, rainfall, and
soil type.
b. Substitutions may be made within
each mixture.
c. Consider effectiveness, temporary
or permanent establishment, cost,
and aesthetic values.
d. Add quantity of needed fertilizer.
3. If the problem area lies near or on a
regional boundary, the listed types of
plants from both regions may be consid-
ered.
4. Seeding rates assume broadcast seeding.
If drilled the seeding rate may be re-
duced to one-half of recommended
rates.
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USD A Soil Conservation Service
Photo 9. This Subdivision Road Fill was Seeded to Intermediate Wheatgrass, and the Grass is Effectively Stabilizing this Roadside.
Elevation is 7,000 Feet, and the Material is Decomposed Granite. (El Dorado Co.)
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35
I CENTRAL VALLEY
H FOOTHILLS OF SACRAMENTO VALLEY
IE CENTRAL COAST AND FOOTHILLS
OF SAN JOAQUIN VALLEY
SOUTHERN CALIFORNIA < 3,000'
NORTH COAST
HIGH ELEVATION > 3,000'
DESERT
NOTE : ILLUSTRATION PREPARED BY
CALIFORNIA DIVISION OF RESOURCE CONSERVATION
AND BURGESS L. KAY (U. C. AT DAVIS)
Figure 7. Location Map for Regional Guide for Grass, Legumes, Shrubs.
-------
TabU 4. Regional Guide for Gnus, Legumes, Shrubs for Region ICentral Valleys.
(Annual Precipitation: 5" to 22")
TYPE VEGETATION
Barley 2/
Italian or
Wimmera Ryegrass _3/
Wild Oats
Australian Saltbush 4Y
Saltgrass 5J
Red Brome
PURE LIVE SEED* (Ib/acre)
NON ALKALINE SOILS
I/
Mixture No. 1
200
I/
Mixture No. 2
50
..
If
Mixture No. 3
200
4-6
ALKALINE SOILS IN SAN JOAOUIN VALLEY
Saline
Mixture No. 4
4-6
Mixture No. 5
rhizomes
Non-Saline
Mixture No. 6
50
I/ Provides first year protection but will have a weedy appearance if not landscaped with shrubs; useful for
temporary erosion control.
2J Grows faster than Italian ryegrass.
3J Italian ryegrass provides better ground cover due to greater number of seeds.
_4/ This is a low growing shrub and may be direct seeded (best seeded without oats because of competition).
5j Must be planted from rhizomes.
NOTE: Oats and ryegrass under arid conditions will grow adequately as a grass. Filaree (Erodium cicutarium) is
very suitable, but the seed is not commercially available.
4.D i . , /,,. \ Pure Live Seed (Ibs)
*Bag seed required (Ibs) - r^^.^,^ fA^4m»l'
Germination (decimal) x Purity (decimal)
Fertilizer: 1) Type: 16-20-0.
2) For less than 15" annual precipitation use 250 Ibs/acre.
3) For greater than 15" annual precipitation use up to 500 Ibs/acre.
Chart prepared by California Division of Resource Conservation using data from 13/, 28/. 36/. 43/.
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Table 5. Regional Guide for Grots, Legumes, Shrubs for Region IIFoothills of the Sacramento Valley.
TYPE VEGETATION
Blando Brome I/
California
PoDDies
Lupine 4/
Wilton Rose Clover 3/ 4/
Crimson Clover 3/ _4/
Lana Woolypod Vetch 4/
Palestine Orchardgrass
Smilo
PURE LIVE SEED* (Ibs/acre)
Entire Region
fixture No.l
40
2/
Mixture TTo.2
5
2
5
20
2
10-20
Above 1000' Elev.
Mixture No. 3
20
2-4
I/ Italian or Wimmera ryegrass may substitute for part of total, but
because it will not reseed itself, the ryegrass alone is useful only
for temporary erosion control.
_2/ This mixture to be used when appearance is a major consideration.
3/ Bur clover and other medics should be substituted for clovers in basic
soils (pH 7.0 and above).
4/ Legume inoculation by U.C. Pellet method recommended and costs about
.10 per pound.
Note: Lana Vetch has unfavorable aspects, because it is an excellent feed
for wild animals, and its vines may create fire hazards. However^ it
does provide fast effective erosion control.
Fertilizer: 1) Type: 16-20-0.
2) Use 250-500 Ibs/acre for the entire region, lesser amount in areas
of lowest rainfall.
*Bag seed required (Ibs)
Pure Live Seed (Ibs)
Germination (decimal) x Purity (decimal;
Chart prepared by California Division of Resources Conservation using data from 13/, 2&J, 36/. 43/.
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38
Table 6. Regional Guide for Grots, Legumes, Shrubs for Region IIICentral Coast and Foothills of the Son Joaquin Valley.
(.Annual Precipitation: 7" to 40")
(Elevation: 100' - 2,500')
TYPE VEGETATION
Red Brome
Blando Brome 6/
Hykon Rose Clover 2/
Crimson Clover 2/
California Poppies
Lupine 2/
Shrubs (Optional) 4/
Lana Woolypad Vetch 2/
Italian Ryegrass
PURE LIVE SEED* (Ib/acre)
Annual . , , .
'recipitatior
<15"
40 I/
Nictitation
5-15"'
Mixture No. 2
40
37
fixture UTo.3
5
20
10
2
5
10-20
Precipitation
Limitation
Mixture No. 4~
50
_!/ May use blando brome if unavailable.
_2/ Legume innoculation by U.C. Pellet method recommended and costs about 10 cents
per pound.
3/ Less erosion protection but more color.
4/ Shrubs for aesthetics and long term erosion control, California buckwheat,
Australian saltbush (California buckwheat is considered a fire hazard in
some areas).
jj/ To be used only for temporary protection during intermediate stages of
construction.
6/ Resource Conservation Districts recommend 18# per acre for flat-sloping agricultural
conditions.
NOTE: a) Although it is desirable to plant poppies for aesthetic reasons, they
will not grow in the first and second alternative mixtures. The
reason is that the grasses are too competitive. The Division of
Highways has had such an experience along Interstate 80.
b) Spanish broom spreads undesirably.
Fertilizer: 1) Type: 16-20-0.
2) Use 250-500 Ibs/acre for the entire region.
.._. , . , /n, x Pure Live Seed (Ibs)
*Bag seed required (Ibs) = n .«... /.Q'.mo1
Germination (decimal) x Purity (decimal)
Chart prepared by California Division of Resources Conservation using data from 13/,
» 43/.
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39
Table 7. Regional Guide for Grass, Legumes, Shrubs for Region IVSouthern California.
(Elevation Below 3000 Feet)
PURE LIVE SEED*(lb/acre)
TYPE VEGETATION
Mixture No. 1 IMI vi-11 r<= Nn. 2
Blando Brome L/
Australian Saltbush
-lllll ^^
Sweet Alyssum
Other Plants 3/
I/ Bed Brome may substitute; either may be considered
a fire hazard and unsightly.
2/ This alternative is a mixture of shrubs and flowers
and would avoid fire hazard of annual grass.
_3/ These plants may be added: African daisy, Spanish
broom, California buckwheat (may be fire hazard),
Lupine, California poppies, alfalfa.
Note
a)
b)
c)
d)
Wild oats are an unsightly grass.
Bur clover or other annual medics may perform
satisfactorily.
Field observations have shown that alfalfa will
grow under less moisture conditions. Alfalfa
is seen as a desirable plant by the Division of
Highways because of its deep-rooted nature,
giving slope stability; it may be unsightly.
For irrigated slopes, Baccharus piluaris
(Coyote Brush) is used extensively in Southern
California coastal areas.
Fertilizer:
1) Type: 16-20-0.
2) For seed mixture No. 1 use 200-400 Ibs/acre.
3) For seed mixture No. 2 use 250-500 Ibs/acre.
*Bag seed required fib*) =
*>ure
Seed (Ibs)
GerAd:tULtim decimal x Purity ecma
Chart prepared by California Division of Resource Conservation using data from
13/, 28/, 367, 437.
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40
Table 8. Regional Guides for Grass, Legumes, Shrubs for Region VNorth Coast.
(Annual Precipitation: 35K to 100")
TYPE VEGETATION
Palestine or Berber
Orchardgrass
Blando Brome
Mr. Barker Subclover I/
Highlands Bentgrass
PURE LIVE SEED* (Ib/acre)
Entire
Region
14txture No.l
20
10
20
North of
Garberville
Mixture No ..2
10
20
20
I/ Crimson clover may substitute up to 50% for color9 and it
should be inoculated by the U.C. Pellet method.
Note: a) Tall fescues grow too tall but tolerates mowing.
For this region, soils are too acid for Bur Clover.
*Bag seed required (Ibs) -
Live Seed (Ibs)
Germination (decimal) x Purity (decimal)
Fertilizer: l) Type: 16-20-0.
2) Use 500 Ibs/acre for the entire region.
Chart prepared by California Division of Resource Conservation using data
from 13/, 28/, 36/, 43/
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41
Table 9. Regional Guide for Grass, legumes, Shrubs for Region VIHigh Elevation
Above 3000 Feel.
(Annual Precipitation: 10m to>40tr)
TYPE VEGETATION
Potomac Orchardgrass _£/
Sherman Big Orchardgrass
Durar Hard Fescue
Wheatgrass 4/
PURE LIVE SEED* (Ib/acre)
Annual Pre-
cipijajpn
I/
Mixture No.l
20
20
Annual Precipitation
2/
Mixture No. 2
20
20
2/
Mixture No. 3
20
20
I/ Potomac variety available in quantity. Avoid I iestine and
Akaroa.
2/ Fescue and orchardgrass may be interchanged.
3/ Potomac orchardgrass for this region is prefer? 3d over Akarja
because it is cold-tolerant.
4/ Preferred wheatgrass: Topar pubescent, Luna pubescent, and
Sodar streambank. Less preferred due to tall growth: Oahe,
Greenar, Tegmar, Amur intermediate, Norden crested.
Note: a) Although the Modoc Plateau is climatically different
from the west side of the Sierras, the recommended
plants are essentially the same. Bitter Brush (Purshia)
may be applied in the Modoc Plateau on some soils.
b) In the Owens Valley area there is a zone which requires
a different type of vegetation,;but because the scale
of the map is small, the area is too narrow to dif-
ferentiate.
c) Cheat Grass (Bromus tectorum) is a serious fire hazard
and is so considered by the Agricultural Research
Service. Furthermore, because it is an annual grass
it survives with difficulty in the granitic soils where
the seeds must blow and fall into cracks in order to
germinate.
d) Bottle Brush Squirrel Tail is all right, but the seed
is not commercially available. Ryegrass definitely
will not grow except as temporary cover.
e) For information on shrubs to be applied in Region VI,
refer to Section 21.40 "Shrubs for the Lake Tahoe Area and
other Regions with Similar Climatic Conditions."
*Bag seed required (Ibs) =
Pure Live Seed (Ibs)
Germination (decimal; x i-urity (decimal;
Fertilizer: l) Type: 16-20-0.
2) For poorly-drained shallow soils 01 well-drained
soils use 250 Ibs/acre every spring until established.
3) For poorly-drained deep soils use 250 Ibs/acre. Initial
application may be sufficient.
Chart prepared by California Division of Resource Conservation using data from 3-3_/, 28/t
36/, 43/.
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42
Table 10. Regional Guide for Grass, Legumes, Shrubs for Region VIIDesert.
Region VII - Desert
(Annual Precipitation: < 10")
TYPE VEGETATION
Four Wing Saltbush I/
Indian Ricegrass 2J
PUKE LIVE SEED* (Ib/acre)
Entire Region
Mixture No.l
5-10
Sandy Soils
Mixture No. 2
5-10
I/ This native shrub available commercially. Spot
seed or drill.
2/ Seeds in short supply; difficult to establish
stands. Drill.
Note: G-alleta would be acceptable for the sandy washes
or alluvial fans in the desert region if the
seed is available.
*Bag seed required (Ibs)
Pure Live Seed (Ibs)
Germination (decimal) x Purity (decimal;
Chart prepared by California Division of Resource Conservation using data
from 13/, 28/, 36/, 43/.
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43
21.40 SHRUBS FOR THE LAKE TAHOE
AREA AND OTHER REGIONS WITH
SIMILAR CLIMATIC CONDITIONS
[19]
21.41 GENERAL
6. Slow-release type fertilizers are recom-
mended.
7. Sulfur is lacking under Sierran soil con-
ditions; therefore, the addition of sulfur
in fertilizer is needed.
The establishment of shrubs in addition to
grass in the Lake Tahoe area is preferred
over grass alone in order to reduce the long-
term erosion damage and to promote the aes-
thetic value of natural vegetation. As a
group, shrubs are more adaptable then
grasses in this region because of the cool cli-
mate, sterile subsoils, and a short growing
season.
Shrubs established concurrently with grass
for erosion control may result in excessive
competition for moisture and nutrients,
thereby inhibiting the early stage of shrub
growth. Yet, there is the continuing need to
protect the soil from erosion using grass until
shrubs attain adequate size.
The task of establishing shrubs involves the
problems of collecting native seeds (seed
from desired species may not be available),
how to reduce the germination time (Pine-
mat Manzanita under natural conditions
takes about two years), developing "cut-
tings", fertilizer considerations, and the tim-
ing necessary to avoid frost damage
(Appendix 11B. Freeze-Free Chart).
21.42 PLANTING CONSIDERATIONS *
1. Stepped slopes are preferred for estab-
lishing shrubs by direct seeding.
2. Hydromulching after shrubs have been
planted creates no problems.
3. Plants from one gallon cans compared to
2" peat-pots has higher survival rates.
4. Machines may be used to dig the holes
for planting (See Photo 10).
5. Willow wattling on cut slopes provides
erosion control as well as willow growth.
However, the cost is high ($5 to $10 per
square yard), and there is always the
potential danger of concentrated water
flowing from the wattling causing deep
ruts. This method is described in refer-
ence No. 33.
21.43 DATA ON SHRUBS [19]
1.
2.
3.
4.
Ceanothus (Squaw Carpet) and Penste-
mon newberri have moderate to high
survival rate of transplants on benches.
It can be grown at low elevation such as
in the Sacramento Valley and planted in
the spring at Lake Tahoe even though
light frost may still be expected.
Cornus stolonifera (American dog-
wood) has a survival rate of uprooted
cuttings from 6% to 16%.
Purshia tridentata has good germination
(75%) with seeds treated with thiourea.
Salix (Willow) has a survival rate of un-
rooted cuttings from 14% to 29%. The
survival rates indicate that these species
can be planted in much drier sites than
where they grow naturally. The low cost
of planting this type of material makes
even a 25% survival level an attractive
revegetation method.
21.50
LEGUME INOCULATION BY U.C. PEL-
LET METHOD [58]
21.51 GENERAL
1. Legumes, if not properly inoculated, will
reduce the percent germination and,
consequently, the effectiveness of seed
mixtures utilizing legumes.
i
2. Legumes live in a symbiotic relationship
with certain nitrogen-fixing bacteria
(Rhyzobium).
3. Other plants adjacent to legumes also
benefit from the availability of nitrogen.
4. To ensure optimum nitrogen fixation
legume seeds should be inoculated with
a desirable strain of bacteria.
5. Legume inoculation by the U.C. Pellet
Method results in each seed pellet con-
sisting of a legume seed, the bacteria
-------
44
inoculant, an adhesive, and a protective
coating material.
6. The cost of inoculation is about ten cents
per pound.
21.52 INOCULANT
1. A fresh, good quality peat inoculant,
specifically made for the legume to be
planted, can be obtained where the seed
is purchased (check expiration date on
package.)
2. Use four times as much inoculant as is
recommended on package in order to
overcome the abundant but ineffective
"wild" bacteria present in many Califor-
nia soils.
21.53 ADHESIVE
1.
Use gum arabic containing no preserva-
tive, technical grade powder, or gran-
ules fine enough to pass an 8-mesh
screen.
Do not use after 24-48 hours have
elapsed since dissolving.
2.
21.54 PROTECTIVE COATING ON SEED
1. Ground calcium carbonate has been
found to be the best material and is mar-
keted in containers labeled calcium car-
bonate, Calcite, Enamel White, or 280
Whiting.
2. Eighty percent of ground calcium car-
bonate should pass a 200-mesh screen.
21.55 PREPARATION
1. Dissolve four pounds of gum arabic in
one gallon of water. It dissolves more
rapidly in hot water but do not boil.
2. Cool gum arabic solution, add appropri-
ate amount of peat inoculant and stir to
a smooth slurry. (Do not leave mixed for
more than % hour before adding calcium
carbonate).
3. Pour the seed into a cement mixer.
4. Add gum inoculant mixture and rotate
mixer until all the seed is wet before add-
ing the calcium carbonate. Run mixer at
high speed.
5. Add calcium carbonate without stop-
ping mixer and let mixer run until seed
is pelleted. The seed is now ready to
plant, but it is better to let the seed sea-
son for a day.
6. The quantities of ingredients vary with
seed size as shown in Table 11.
21.56 PLANTING
1. The bacteria will survive in sufficient
numbers for only three weeks or so.
2. It is best to plant immediately after pel-
leting and within two weeks prior to the
winter rainy season.
-------
Photo 10. Digging Holes for Shrubs and Trees for Slope Stabilization and Beautification. (San joaquin Co.
USDA Soil Conservation Service
Table 11. Seed Type vs. Inoculant Quantity. [58]
Seed Type
Vetch
Subterranean, rose
and crimson clover
Alfalfa, bur clover
Seed Amount
100 Ibs.
100 Ibs.
100 Ibs.
Gum Arabic Solution
21/2 quarts
5 quarts
5 quarts
Calcium Carbonate
30 Ibs.
50 Ibs.
40 Ibs
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46
21.60 COMMON AND SCIENTIFIC NAMES OF PLANTS
COMMON NAME
African daisy
Alfalfa
Barley
Bermuda Grass
Brome
Blando
Red
Bur Clover
California buckwheat
California poppy
Crimson clover
Dogwood, American
Fescue, hard (Durar)
Highland bentgrass
Lupine
Manzanita
Oak
Orchardgrass, Palestine
Penstemon
Pinemat manzanita
Ricegrass, Indian
Rose clover
Hykon
Wilton
SCIENTIFIC NAME
Arcotis staechadifolia
var. grandis
Medicaga sativa
Hordeum spp
Cynodon Dactylan
Bromus spp
B. mollis
B. tectorum
Medicago hispida
Eriogonum fasiculatum
Eschscholzia californica
Trifolium incarnation
Com us stolonifera
Fesiuca ovina duriuscula
Agrostis tenuis
Lupin us spp
Arctostaphylos spp
Quercus spp
Dactylis glomerata
Penstemon spp
Arctostaphylos nevadensis
Oryzopsis hymenoides
Trifolium hirtum
T. hirtum, var
T. hirtum, var
COMMON NAME
Ryegrass, Italian
Salt bush
Australian
Four wing
Salt grass
Sherman Big Bluegrass
Smilo
Spanish broom
Squaw carpet
Subclover
Sweet alyssum
Vetch, lana woolypod
Wheatgrass
Crested (Nordan)
Intermediate (Amur,
Greenar)
Oahe
Pubescent (Luna, Topar)
Streambank (Sodar)
Western
White Buck Brush
Wild Oats
Willow
SCIENTIFIC NAME
Lolium multiflorum
Atriplex spp
A. semibaccata
A. canescens
Distichlys spicata
Poa ampla
Oryzopsis miliacea
Spartium junceum
Ceanothus prostratus
Trifolium subterraneum
Alyssum marithna
Vilia dasycarba
Agropvron spp
A. desertorum
A. intermedium
A. trichophorum
A. Riparium
A. smithii
Ceanothus cuneatus
Avena fatua
Salix spp
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47
22.00 SEEDING METHODS
22.10 GROUND PREPARATION
1. Seed shall be placed on mineral soil. [6]
2. Seed shall be covered by soil or mulch.
[6]
3. Soil surface shall be roughened to a
depth of 2" so that the seed will remain
in place. [6]
4. In clayey soil, seed must be % inch below
ground surface. [13]
5. In sandy soil, seed must be l/2 inch to 1
inch below ground surface. [13]
6. Seed must be evenly distributed.
7. Seeding shall not be performed when, in
the opinion of the inspector or engineer,
weather or ground conditions are unsuit-
able for this operation.
8. Stepped cup slopes shall conform to the
specifications in Section 23.
22.20 MANUAL BROADCASTING [13]
1. Breast seeders are very inexpensive.
2. Labor cost per acre is 2 to 3 hours times
cost/hour.
3. To be used on:
a. Cut and fill slopes where seed is
raked into soil.
b. Fills where straw is punched into
slope.
c. Rocky fill slopes where first rains
cover seeds.
d. Rocky cut slopes to be seeded with
shrubs.
e. Benches or stepped slopes where
natural sloughing of soil will cover
the seed.
22.30 DRILLING
1. The grain drill with grass seed attach-
ment places both the seed and fertilizer
at proper depth and at approximately 4
inch intervals.
2. Drill shall go across the slope, not up
and down the slope. To be used on slopes
less than or equal to 3:1 (horizontahver-
tical).
3. When drilling the seed and fertilizer re-
quirements in Section 21.30 may be re-
duced up to 50 percent.
22.40 HYDROSEEDING HYDROMULCHING
1. GENERAL
a. Hydroseeding/hydromulching is
the process of spraying seed, mulch,
and fertilizer using a jet of water ap-
plied under pressure (Photo 11).
b. Shall be used on steep slopes too dif-
ficult to manual broadcast or drill
and on serrated cuts where it is in-
tended to wash seed into cracks and
crevices. [55]
c. Hydromulching shall not be used
under conditions of high tempera-
tures and winds unless irrigated be-
cause it would blow away.
d. Surface of slope shall have been be
roughened to a depth of 2 inches.
2. Hydroseeding
a. Seeds may be applied without fiber
when using a gear pump. [13]
b. Seeds shall be applied with fiber
when using a recirculating centrifu-
gal pump. [13]
c. When fiber is used to ensure an even
suspension of seed, a maximum of
150 pounds of fiber per 1,500 gallons
of water is recommended. [55]
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48
d. If a slurry or water carrier is used,
erosion control materials shall be
applied with a photo-sensitive dye
which will produce a green color
when sprayed upon the ground. The
color shall disappear within 2 or 3
days after being applied and shall
not stain concrete or painted sur-
faces, nor injure plant or animal life
when applied at the manufacturer's
recommended application rate.
3. Hydromulching [55]
a. Fiber shall be applied to the slopes at
a continuous and uniform rate,
forming a fiber mat thickness of I/
16" minimum and 1/8" maximum.
[6]
b. The application rate of fiber shall be
a minimum of 2,000 Ibs/acre. See
Section 35.06, Wood Fiber.
c. Frost heave will damage fiber mat:
proper surface and subsurface drain-
age measures shall be used to mini-
mize the occurrence of frost heave.
[27]
d. The amount of seeds may be in-
creased above that recommended in
Regional Guide for Plants,
Legumes, Shrubs, to compensate for
losses due to suspension of seed in
fibers.
e. Material which inhibits germination
or growth shall not be present in the
mixture.
f . Mixing shall be performed in a tank,
with a continuous agitation system
of sufficient operating capacity to
produce a homogeneous slurry of fi-
ber, seed, fertilizer, and water in the
designated unit proportion.
g. With the agitation system operation
at part speed, water shall be added to
the tank.
h. The seed shall be added first; then
fertilizer shall be added, and then
the fiber. (If a centrifugal pump and
recirculation is employed, fiber is
added before seed). [12] [55]
i. The fiber shall not be added until the
tank is at least one-third filled with
water.
j. The mixture shall be agitated at full
speed when the tank is half-filled
with water.
k. All fiber shall be added by the time
the tank is two-thirds to three-
fourths full.
1. Maximum permissible time of mix of
fertilizer and seed shall be one hour
in order to prevent deterioration of
seed.
m. The application of seed to serrated
slopes shall be done in two separate
operations:
1. The first operation shall mix
water and seed with just enough
fiber to ensure an even suspen-
sion of seed, but not more than
150 pounds per 1,500 gallon
mix. This shall be spread with
the intent of washing the seed
into the cracks and crevices on
slope.
2. The second operation shall ap-
ply fiber mulch material and
fertilizer at the minimum rate of
2,000 pounds of fiber per acre.
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49
California Department of Transportation
Photo 11. Hydroseeding-Hydromulching Operations at Luther Pass in El Dorado County, Highway 89.
-------
50
22.50 SPOT SEEDING OF SHRUBS [34]
1. Spot seeding of shrubs is the application
of seeds by hand in regular intervals,
called seed spot basins (Figure 8).
2. The high cost of seeds of many shrubs
makes spot seeding relatively more eco-
nomical compared to broadcasting
which results in a higher mortality of
seeds.
3. Procedure for Spot Seeding:
a. Dig a 4inch deep hole with a hand
pick or trowel (Figure 8). If com-
pacted, soil should be pulverized
with a shovel or soil auger.
b. Place one gram (0.03 ounce) of ni-
trogen as a slow-release fertilizer
containing phosphorous and sulfur
in the bottom of the hole.
c. Replace and firm the soil in the hole,
leaving a slight depression, depend-
ing on the size of the seeds to be
planted (Table 12).
d. Place 3-100 seeds in the planting
depression (Figure 9) and cover
with pulverized soil and firm soil.
1. If irrigation is available for ger-,
mination and during the first
season, seeding rate can be re-
I duced by one half (Figure 9).
j
2. Better to plant more spots than
to increase the number of seeds
per spot.
3. The sowing rate to provide ade-
.quate stocking of seed spots de-
pends on the germinability and
seed size.
e. Remove any loose, excess soil so it
will not blow or wash into the seed-
ing holes.
f. On slopes, pockets with slight back-
slope help prevent seed spot from be-
ing covered by loose soil from above
(Figure 10). Backslope concentrates
water so it is available to the seed-
lings later.
g. In rocky surfaces, place seed in
depressions or crevices which ac-
cumulate soil of fine rock fragments.
h. Effective weed control shall be ac-
complished by herbicides or sheet
mulch (Figure 11) or wood chip
mulch (Figure 12).
i. Instructions for using herbicides are
the following:
1. Apply a contact herbicide (e.g.,
diquat or diquat dibromide,
paraquat, etc.) after seeding,
but before seedling emergence
and when the weeds are less
than 3 inches high.
2. When applying contact herbi-
cides, carefully read and follow
the governmental recommenda-
tions and safety precautions
giveri on the container label.
3. Spray in a circle 3 to 4 feet in
diameter around each seed spot.
4. If seedlings have emerged, in-
vert an empty can over them
before spraying.
5. A second application may be
needed if new weeds emerge.
6. Two applications will usually
give adequate control for the en-
tire growing season on nonirri-
gated plantings.
-------
51
4'-
SPOT SEEDING HOLE
LEVEL
V8?1/2'\
I '".' ' ' ' ' | SEEDING DEPTH APPROX
1 I2-3X SEED DIAMETER
I /
5" 1 /
\ !
\ 1
\ 1
\ I
\ i
\ / FERTILIZER
Figure 8. Planting Seeds in a Seed Spot
Basin Provides for Proper Fertilizer Place-
ment, Seeding Depth, and Moisture Ac-
cumulation. [34]
Figure 9. Approximate Number of Seeds
to Plant in Each Seed Spot Depending on
Seed Size and Germinability Under Non-
Irrigated Conditions. [34]
lOOh
10% Germinability
Seed Size -in.
SPOT SEEDING
SLOPE
Figure 10. A Pocket Formed in the Slope
Helps to Accumulate Water Near the Seed-
ing Spot and to Prevent Loose Soil Above
From Covering the Spot. [34]
-------
52
PAPER MULCH.FLAT SURFACE
Figure 11. Sheet Mulch on Soil Surface with Opening Over Seed Spot for Weed Control and
Reduction of Evaporation from the Soil. [34]
. 3"OPENING
OVER SEEDINC
HOLE
COLLAR SEED. HOLE
WOOD CHIP MULCH BASIN-)
COLLAR 4"x4"xs"
ULCH-2"AI COLLAR
^FERTILIZER
Figure 12. Two Methods of Planting Seeds in a Collar to Hasten Germination
and Control Weeds. [34]
COLLAR SEED. HOLE
WOOD CHIP MULCH BASIN 2
21/2" 3(l/2" ^MULCH
Table 12. Depth of Seeding Depression, Soil Depth Over Seed and Depth of Depression for Moisture for Various Seed
Sizes. [34]
Seed
diameter
(inch)
<1/16
1/16 -1/8
1/8 - 1/4
1/4 - 1/2
Seeds
Per*
hole
30
20
10
5
Depth of
seeding depression
below surface,
(inch)
1/4 - 3/8
3/8 - 1/2
1/2 - 3/4
7/8 - 1
Depth of
soil
over seed,
(inch)
1/8
1/8 - 1/4
1/4 - 3/8
1/2
Depth of
depression
for water,
(inch)
1/8 - 1/4
1/4
1/4 - 3/8
3/8 - 1/2
*Based on 50% germinability (See Figure 9).
-------
53
23.00 STEPPING OF CUT SLOPES [4][45] [61]
23.10 PURPOSE AND DESCRIPTION
Stepping provides for the development of
vegetation on soft rock cut slopes which nor-
mally cannot support vegetative cover. Such
soft rock cut slopes occur frequently along
roadcuts and mining quarries. See Photos 12
and 13.
The effectiveness of vegetating steep slopes is
greatly increased by the stepping of cuts.
Stepping cut slopes is the construction of
square steps along the slope of a cut (Figure
13). The steps are cut by a dozer as the exca-
vation proceeds downward. The two meth-
ods of stepping of cut slopes are scarifying
(Photo 12) and serrating (Photo 13). The
main difference between scarifying and ser-
rating is that the widths of the steps in scari-
fying are 8" to 10" and in serrating are 2' to
4'.
The flat portions of the steps prevent seed
and mulch from blowing or washing away.
The gradual crumbling of the steps covers
the seed with soil and provides protection
against loss of seed and also adds moisture
retention. Stepping should not be performed
on unstable cut slopes (See Photo 14).
The cost of stepped slopes is not substantially
greater than normal slope preparation meth-
ods because of the following:
1. Slopes are not fine graded.
2. No substantial increase in excavation
; due to midpoint of steps placed on slope
line.
3. Steps are level and are relatively easy to
check.
4. Easier to correct grading errors on steps
compared to grading errors on smooth
slope construction.
23.40 SCARIFYING
23.41 GENERAL
1. Scarifying is the construction of approxi-
mately 10" width horizontal steps on the
entire slope of a cut. (Photo 12).
2.
3.
A special blade on a dozer with a series
of 10" square grooves and held at the
angle of the cut scarifies the slope.
Scarifying is limited to medium to highly
cohesive soils rather than loose, granular
soils or where ripping is required.
23.42 SPECIFICATIONS FOR SCARIFYING
1. Scarifying shall be applied on cuts in
cohesive soil or in soft rock which can
be excavated without ripping.
2. The steps shall be approximately
square with horizontal dimensions of
8" to 10".
3. The approximate midpoint of the hori-
zontal tread of the step shall be con-
structed on staked slope line.
4. Steps shall be approximately horizon-
tal; however, they may parallel the
roadway grade if it is less than 2 per-
cent.
5. Steps shall have vertical back slopes
with the shelves being within +5 per-
cent horizontal.
6. Excavation of each step shall be in the
opposite direction from the preceding
one to minimize build-up of loose
material at the ends of steps.
7. Loose material which collects at the
end of steps shall be removed and the
ends blended into the natural ground.
8. Scarifying shall not be allowed in the
zone of the lowest steps because loose
material tends to fall out of the slope.
9. Scaling need not be performed on the
stepped slope except for removal of
material which may fall into the ditch-
line or roadway or rock fragments
larger than 1/3 the shelf width.
10. In excavating material that weathers
rapidly, the seeding and mulching op-
erations shall be delayed until approxi-
mately half of the step width has been
filled with slough material to prevent
smothering the seed.
-------
54
23.50 SERRATING [4] [61]
23.51 GENERAL
1. Seriating is the construction of a con-
tinuous series of large horizontal steps
on rippable soft rock cut slopes (Photo
13).
2. Serrations are practical only for slopes
consisting of soft rock ("rock which can
be excavated by ripping").
3. Serrations are not feasible in cuts con-
sisting of rock which requires blasting.
4. Serrations are not practical in cuts con-
sisting of soft rock which is laminated in
comparatively thin layers so oriented
that the strike is approximately parallel
to the roadway centerline and with the
dip approximating the staked slope line.
5. Serrations are of little value on slopes
flatter than 2:1 ratio. (horizontal:verti-
cal)
23.52 SPECIFICATIONS FOR SERRATING
1. Cuts in soft rock, as shown on the plans
or designated by the engineer, shall be
excavated to shape the cut face to a
stepped pattern in reasonably close
conformity with the typical cross-sec-
tion shown on the plans. (Figure 13)
2. The steps may vary from 2 to 4 feet
vertically, with the horizontal dimen-
sions being a function of the staked
slope ratio.
3. The approximate midpoint of the hori-
zontal tread of the step shall be con-
structed on the staked slope line.
4. The first step shall begin immediately
below the soft-rock line and continue
to the bottom slope.
5. Serrations shall be approximately hori-
zontal; however they may parallel the
roadway grade if it is less than 2 per-
cent.
6. Serrations shall have vertical back
slopes with the shelves being within -f
5 percent of horizontal.
7. Excavation of each step shall be in the
opposite direction from the preceding
one to minimize build-up of loose
material at the ends of steps.
8. Loose material which collects at the
end of steps shall be removed and the
ends blended into the natural ground.
9. Where rock too hard to rip is encoun-
tered within a cut the slope shall be
blended into the rock.
10. Scaling need not be performed on the
stepped slopes except for removal of
material wich may fall into the ditch-
line or roadway or rock fragments
larger than one-third the shelf width.
11. It may be desirable to require that the
outer edge of the step be knocked off
(cambered) during construction to
reduce the sharp geometric lines on the
slope and provide loose material which
may support native growth.
12. In hard material that weathers slowly,
seeding and mulching shall be per-
formed immediately after construction.
13. In excavated material that weathers
rapidly, the seeding and mulching op-
erations shall be delayed until approxi-
mately half of the step width has been
filled with slough material to prevent
smothering the seed.
14. On both stepped cut faces and smooth
cut faces, every reasonable attempt
shall be made by the designer to pro-
vide sufficient right-of-way (or grad-
ing easement) to permit each cut to be
rounded (longitudinally and vertical-
ly) enough to eliminate plane cut sur-
faces. (Figure 14).
-------
^-:''&
Photo 12. Scorifying of Cut Slopes. (I 80, Placer Co.)
California Division of Resource Conservation
-------
56
California Division of Resource Conservation
Perry Y. Amimoto, California Division of Mines and Geology
Photo 13. Serrating of Cut Slopes. (ISO, Applegate, Placer Co.)
-------
57
Perry Y. Amimoto, California Division of Mines and Geology
Photo 14. This Landsliding of a Serrated Cut Slope Occurred Because the Foundation Material was Unstable Serpentine. (Lake Co.)
-------
58
I. Staked slope line for soft rock variable slope ratio
2. Step rise: Height (variable 2to 4 feet)
3. Step tread: Width (stoked slope ratio X step rise)
4. Step termini; Width (1/2 step tread width)
5. Overburden area. Variable slope ratio
6. Slope rounding
Hinge Point
Figure 13. Typical Section for Serrated Stepped Slopes in Soft Rock. [61]
THIS
NOT THIS
t i / !
1 \
\ \V
N V.1
\ ^r
Roadway
Original ground contour
Final grade contour
Figure 14. Rounded Cut Faces on Serrated Slopes.
-------
24.00 TOPSOIL SPECIFICATION
Topsoil would provide for vegetation growth
on severe cases of rock or hard pan (Photo
15).
Topsoil should not be applied to a cut slope
exceeding 2:1.
24.10 SPECIFICATIONS
1. It shall be obtained from well-drained
arable land and shall be reasonably free
from subsoil, refuse, roots, heavy or stiff
clay, stones larger than one inch in size,
coarse sand, noxious seeds, sticks, brush,
litter, and other deleterious substances.
[38]
2. Topsoil shall not be placed when exces-
sively moist.
3. When the topsoil is liVolv to slin down-
slope it snould be placed on well-rough-
ened surface scarified to a minimum
depth of 3 inches. [21]
4. Average depth of 1 foot. Minimum
depth of 6 inches. [42]
5. The topsoil shall be properly compacted.
6. Topsoil shall meet gradation and chemi-
cal requirements of Table 13. [42]
25.00 PLANTING PERIOD AND IRRIGA-
TION CRITERIA
25.10 PLANTING PERIOD
1. Planting should generally follow im-
mediately after the completion of grad-
ing and before a hard crust has formed
on the ground surface.
2. Seeds may be applied at any time during
summer or fall. Loss of seeds to birds or
insects is minimized by covering the
seeds with soil or mulch.
3. Mulch protection shall be provided for
seeds that are subject to erosion.
4. Mulch applied during midsummer shall
not be allowed to deteriorate by dessica-
tion or wind.
5. For germination by rainfall, legumes
59
shall be planted within two weeks of the
start of the rainy season.
6. The potential for frost damage should be
considered (See Appendix 1 IB, Freeze-
Free Chart).
25.20 TEMPORARY IRRIGATION
1. The higher cost of establishing vegeta-
tion by irrigation may be offset by the
following advantages:
a. Vegetative growth established dur-
ing summer provides protection
against erosion during winter.
b. Greater probability of establishing
good growth due to summer temper-
ature and controlled moisture input.
c. Less loss of seed to birds, rodents,
etc.
d. Savings in mulch protection meas-
ures normally used during the win-
ter.
2. Temporary irrigation systems should
consider the following.
a. Automatic timers preferred over
manual operation. [40]
b. The ground surface must be con-
tinually moist until the rainy season
starts.[401
c. Mulch protection is required when
summer rains are a threat and when
the expected vegetative development
is insufficient to protect erodible
soil.
d. The water should be applied fre-
quently but of such intensity that
excessive runoff does not occur.
e. Drainageways must be constructed
to carry excess runoff away safely.
f. Water leaks between irrigation pipe
joints may cause concentrated run-
off; therefore, the maintenance
schedule should include a frequent
inspection of leaks. [40]
g-
Water shall be free of chemicals and
other substances harmful to the
growth of grass.
-------
USDA Soil Conservation Service
California Division of Resource Conservation
Photo 15. Topsoil Placed on Slopes Along this Freeway Helped to Produce the Lush Vegetation. (Nevada Co.)
-------
61
Table 13. Soil and Chemical Requirements. [42]
FRACTION
GRAVEL
SAND
SILT
CLAY
PARTICLE SIZE (mm) PERCENT
MIN
LARGER THAN 2.0
2.0 - .05
.05 - .002
LESS THAN .002 10$
OF SAMPLE
MAX
20$
65$
80$
35$
TOPSOIL CHEMICAL PROPERTIES REQUIREMENTS
PROPERTY
pH*
ESP+
EC#
*pH NEGATIVE LOGARITHM
MIN
5.5
-
OF THE HYDROGEN ION CONCENTRATION
MAX
8.5
10.0
4.0
+ESP EXCHANGEABLE SODIUM PERCENTAGE
#EC ELECTRICAL CONDUCTIVITY, MILLIMHOS PER CM 6 25 C
-------
63
Section 30
SURFACE PROTECTION WITH
MULCHES AND OTHER MATERIALS
-------
65
31.00 PURPOSE
Protective coverings and mulches are used to
prevent erosion from rainfall impact and
runoff and from the action of wind on dis-
turbed soil such as slopes of cut (smooth-
faced or stepped) and fill including stockpile,
and incompleted fill.
Protective coverings and mulches are sub-
stances including straw, wood products,
chemicals and other materials which prevent
erosion of soil by reducing the effects of rain-
fall impact and runoff and providing a suita-
ble environment for the development of
vegetative cover.
32.00 MULCH QUALITY FOR ESTABLISH-
ING VEGETATION
Mulches to be used for establishing vegeta-
tive growth shall have the following quali-
ties:
1. Able to prevent soil erosion until perma-
nent vegetation is established.
2. Sufficiently porous to allow water to en-
ter.
3. Provide cover adequate to conserve soil
moisture.
4. Capable of minimizing soil temperature
changes.
5. Not toxic to vegetative growth.
33.00 FACTORS AFFECTING THE EFFEC-
TIVENESS OF MULCHES
The physical factors affecting the effective-
ness of mulches include the following:
f. Steepness and length of slope.
2. Soil type and condition.
3. Rate and time of mulch application.
4. Climate
5. Runoff control measures.
34.00 CONTROL OF WIND EROSION
Chemical mulches used to control wind ero-
sion are described in Section 35.08Chemi-
cal Mulch.
35.00 LIST OF PROTECTIVE COVERINGS
AND MULCHES
A list of coverings and mulches including an
estimate of the effectiveness is summarized
in Table 14. The state-of-the-art relating to
the type and method of application of cover-
ings and mulches continually change. There-
fore, the specifications shown in this section
may have been superseded. However, the in-
formation will provide, at the least, an ade-
quate overview of the various materials and
techniques.
-------
66
Table 14. List of Protective Coverings and Mulches.
TYPE MULCH
"PI n Q-J--I r» ^»Vieae>~t"
Straw Alone
Punched Straw
Net-Anchored
Straw
Tackifiers with
Straw
Wood Chip,
Sawdust
Gravel , Stones
Mulch Blanket
Wood Fiber
Washed Dairy
Waste
Wood Chips and
Asphalt
Chemical Mulch
Wood Fiber and
Chemical Mulch
Wood Excelsior
Mat
Fiberglass
Fiberglass and
Asphalt
Jute
Jute and Straw
Sod
Building Block
EFFECTIVENESS
IN IMMEDIATE
EROSION PROTECTION
Hirrh
nign
Medium
Medium
High
High
Medium
High
Medium
Medium
Medium
Medium-High
Medium-High
High
High
Medium
High
Medium-High
High
High
High
EFFECTIVENESS
IN ESTABLISHING
VEGETATION
Medium
High
High
Medium-High
Medium
Medium
Medium
Medium
Medium
Medium
None-Low
High
High
Medium
High
Medium-High
High
High
High
COMMENT
f pmnnT'aT'v u ^p * mulch n!PO
tection for shrubs.
For flat slopes and nonwindy
areas.
Ideal for vegetating fill.
Retains straw on slope.
Straw glued with tackifiers
prevents its blowing away.
For flat slopes, stepped
slopes, seed spot basins.
Provides for mechanical
protection and veget-
ative growth.
Binder dissolved leaving
fiber mat with net.
Applied on roughened
surface.
Equivalent to wood fiber.
Good use of timber waste.
Chemical film increases
cohesion but reduces
porosity.
Improved retention of
fiber on slope and
improved germination.
Covered by net and stapled
in steep or windy 'areas.
Available in loose or matted
form.
May be difficult to mow.
Slope must be smooth.
Slope may be rough.
Some maintenance required.
Stabilizes steep slopes and
provides for vegetation.
SECTION
7K oi
35.022
35.023
35.024
35.025
35.03
35.04
35.05
35.06
35.07
35.032
35.08
35.08
35.09
35.10
35.10
35.11
35. ll/
35.024
35.12
35.13
-------
67
35.01 PLASTIC SHEET [27]
1. Plastic sheets of polyethylene may be
used to:
a. Temporarily protect exposed soil.
(See Photo 16).
b. Protect shrubs during early stages of
growth (see Figure 11).
c. Reduce evaporation and possibly
provide an insulating air layer which
reduces soil temperature.
2. Durability of polyethylene as measured
from a test was:
a. White, clear, orange (1 mil): 6
months
b. Black (1 mil): 12 months
c. Black (3 mil): > 12 months
3. Perforated white polyethylene (1 mil)
provided 10 to 18 degrees cooler soil
temperatures and better growth on a
seeded plot during hot, sunny days.
4. The plastic sheets must be anchored to
prevent wind damage.
5. There may be a potential problem of ani-
mals eating the plastic sheets.
California Division of Resource Conservation
Photo 16. Plastic Sheets Placed on Road Fill Before Paving Prevented Erosion. (El Dorado Co.)
-------
68
35.02 STRAW AND HAY
35.021 GENERAL
1. Types of straw include oat, barley,
wheat, rice.
2. Types of hay include tame, wild.
3. Straw shall be free of mold.
4. A fine-stemmed baled mulch is pref-
erable to a loose mulch for mechanical
spreading.
5. Straw, free from seeds, should be ap-
plied where the establishment of cer-
tain species is desirable and where
competition from "wild" species may
hinder development of planted varie-
ties. Rice straw is best choice. [14] [27]
6. Wild or tame hay may prove effective
in aiding the establishment of native
mixtures of grasses.
7. Straw and hay shall be anchored on
slopes steeper than 3:1.
8. On level areas use beater-type spread-
ers.
9. On steeper slopes use blower-type
spreaders. :
10. Maximum thickness of straw blanket
must be such that the mineral soil
shall be visible beneath the straw
when viewed from above.
11. On small sites, straw may be packed
into the ground with a round blade or
spade.
12. If stable bedding straw is used, 3 tons
per acre should be applied.
35.022 STRAW ALONE (No anchoring)
1. Shall be limited to slopes not exceeding
I 3:1. (Photo 17)
! ' ' '
\2. Is not advisable in windy areas, /
3. Shall be applied at a rate of 2 tons per
acre.
35.023 PUNCHED STRAW [38]
1. Straw shall be applied at 4 tons per
acre, half of which will be punched in.
[14]
2. Straw shall be of sufficient length so as
to be securely anchored and at the same
time extend 2 to 3 inches above surface
after being punched.
3. Straw shall be incorporated into soil
with a roller equipped with straight
studs, made of approximately 7/8 inch
steel plate, placed approximately 8
inches apart and staggered. [38]
4. Roller studs shall not be less than 6
inches long nor more than 6 inches
wide and shall be rounded to prevent,
withdrawing the straw from the soil.
[38]
5. The roller shall be of such weight as to
incorporate the straw sufficiently into
the soil so that it will not support com-
bustion, and will leave a uniform sur-
face.
35.024 NET-ANCHORED STRAW
1. Netting is usually available in rolls 4
feet wide and up to 300 feet long. [41]
2. Straw shall be applied at a rate of 1 % to
2 tons per acre.[41] (Photo 18).
3. Straw shall not be less than 6 inches
long. [27]
4. Staple the paper, jute, cotton or plastic
netting to the soil surface according to
manufacturer's recommendations.
35.025 TACKIFIERS WITH STRAW
1. The liquid tackifier spray is injected
into the stream of straw or hay mulch
as it comes out of the mechanical
spreader, or it may be applied after the
straw is in place.
2. Straw shall be applied at a rate of 2 tons
per acre, and the straw shall not be less
than 6 inches long. [27] [60]
-------
Photo 17. Straw Applied Without Anchoring.
U5DA Soil Conservation Service
Photo 18. Net-Anchored Straw.
USDA Soil Conservation Service
3. When asphalt emulsion is used a rapid
setting emulsion is reauired, and the
straw shall be anchored with asphalt
emulsion at the rate of about 200 gal-
lons per 1 ton of straw. Problems may
result if asphalted straw blows offsite.
[27] [60]
4. Organic and plastic glues are effective
tackifiers. Generally, organic glues at-
tract and hold moisture and improve
germination while plastic glues may in-
hibit germination if not carefully ap-
plied. [17]
5. Table 15, "Effect of Tackifier
Products on Wind Stability of Barley
Straw", shows the results of various
experimental tests. It indicates that
the addition of fiber significantly im-
proves the performance of organic and
plastic glues. [17]
-------
70
Table 15. Effect of Tackifier Products on Wind Stability of Barley Straw. [17]
PRODUCT
No Tackifier
Asphalt
Emulsion
Organic
Glues
Plastic
Glues
\
None
SS-1 Asphalt
SS-1 Asphalt
SS-1 Asphalt
Terratack I
Terratack II
Ecology MB
Aero spray 70
Curasol AH
Soil Seal
SBR-Dow+MC
SBR-Amsco
SBR-Amsco+MC
Chemical
(rate/ac)
200 gal
400 gal
600 gal
40 Ib
89 Ib
44 Ib
88 Ib
85 Ib
58 Ib
87 Ib
127 Ib
142 Ib
50 gal
100 gal
50 gal
100 gal
45 gal
90 gal
180 gal
100 gal
54 gal
60 gal
53 gal
106 gal
59 gal
Piber
(ib/ac)
250
250
146
294
70
146
146
159
125
250
136
135
135
250
75
75
152
84
Water
(gpa)
»-»
1600
3200
728
1470
329
679
679
742
665
500
1000
500
1000
500
1000
2000
1000
357
395
317
639
355
Wind speed at which 50$ of
straw was blown away
(mean value of 4 trials)
9
40
80
84++
69
82
82
84++
83
84
84
84++
68
17
22
44
54
38
64
76
76
56
84
53
84+
68
Note 1. 84+ ~ Very stable at 84 mph.
2. 84++ = Superstable at 84 mph.
3. Barley straw broadcast at 2,000 Ib/acre.
-------
71
35.03 WOOD CHIPS AND SAWDUST
35.031 GENERAL
1. Wood chips and sawdust as mulch is a
good use of timber waste.
2. Wood chips and sawdust should be
used only on flat slopes or steep slopes
which are scarified or serrated.
3. Wood chips may also be used as mulch
for the protection of shrubs.
4. An additional 5 to 10 pounds of nitro-
gen fertilizer per ton of wood chips or
sawdust is needed to compensate for
the loss of available nitrogen for plant
growth. [27]
35.032 WOODCHIPS [38]
1. Wood chips shall be manufactured
from any clean, green softwood.
2. Chips shall be produced by machinery
equipped with knives or blades which
cut rather than shred or break the
material.
3. Chips shall be graded so that substan-
tially all chips are from 1/2 to 3 inches
in length, 1/2 inch to 1 1/2 inches in
width and from 1/3 inch to 1/2 inch in
thickness.
4. Chips produced from tree trimmings
with significant quantities of leaves or
small twigs shall not be acceptable.
5. Wood chips and bark mulches shall be
applied 2 to 3 1/2 inches in depth.
6. Bark mulches may consist of a screened
grind from 1/2 inch to fines, with most
particles 1/50 to 1/8 inch. [27]
7. The lowering of soil pH by wood chips
or bark can be corrected by the addi-
tion of 10 pounds of lime per cubic yard
of wood residue. [27]
35.033 SAWDUST
1. Applied to a depth of 2 inches.
2. Shall be millrun sawdust, chips, shav-
ings. [27]
3. Resaw (fine) sawdust is not acceptable
because it packs tightly, retarding aera-
tion and infiltration. [27]
35.04 GRAVEL AND STONES
35.041 GENERAL
1. Gravel and stones provide long-term
protection against erosion and allow in-
filtration of rainfall for vegetative
growth. (Photo 19).
2. Gravel is also very effective against
wind erosion.
3. Use of gravel is limited to low to mod-
erately steep slopes.
35.042 APPLICATION
1. Fine gravel (1/12 to 1/4 inch diame-
ter) shall be applied at 20 tons per acre.
[27]
2. Medium gravel (1/4 to 1/2 inch diame-
ter) shall be applied at a rate of approx-
imately 50 tons per acre. [27]
3. Coarse gravel (1/2 to 1 1/2 inches in
diameter) shall be applied at a rate of
approximately 100 tons per acre. [27]
4. Gravel (3/4 to 2 inches in diameter)
shall be applied to a 2-inch depth. [42]
-------
Perry Y. Amimoto, California Division of Mines and Geology
Photo 19. Protection of Cut Slope Using Gravel. (Humboldt Co.)
-------
73
35.05 MULCH BLANKET
35.051 GENERAL
1. Mulch blankets are formed as thin
sheets and are composed of cellulose
fibers bonded to a water soluble binder
and meshed with a plastic or cotton net.
2. The mesh openings are 1/4 inch by 1/4
inch and the rolls have a width of 75
inches and a length of 500 yards.
3. When the mulch blankets are saturated
by rain the water soluble binder dis-
solves and the fibers loosen to form a
mulch cover.
4. The mulch blankets may be used along
drainages as well as along slopes of cut
and fill.
5. The blankets are unrolled and stapled
over seeded soil.
35.052 APPLICATION
1. Blankets may be applied down or
across slope.
2. Sufficient overlap should be provided
between rolls to allow for shrinkage.
3. Stapling should be placed according to
manufacturer's instructions.
4. At the top of the slope runoff must be
prevented from flowing beneath the
blanket.
5. Blankets shall be placed loosely and be
in continuous contact with the soil sur-
face.
6. When unrolling blanket across slope
the uphill overlaps shall be on top.
35.06 WOOD FIBER
35.061 GENERAL
1. Wood fibers consist of short cellulose
fibers produced from wood chips.
(Waste paper fibers may not be a satis-
factory substitute.) [12]
2. The fiber disperses into a uniform slur-
ry when mixed with water and the slur-
ry is hydraulically sprayed on slopes
(Photo 11).
3. An advantage of wood fiber mulch is
that a mixture of fertilizer, seed, and
wood fiber can be applied hydraulically
in one operation.
4. Another advantage is that seeding can
be done on slopes too steep to vegetate
by other means.
5. The wood fiber forms a porous mulch
which provides a water-holding
capacity for successful germination
while providing protection against soil
erosion.
35.062 APPLICATION [1] [5] [12] [15] [27] [55]
1. The application of wood fiber is de-
scribed in Section 22.40 - Hydroseed-
ing/Hydromulching.
2. The wood fiber shall be applied in the
following amounts depending on the
type of wood fiber: ;
a. Alder or Aspen: 3,000 Ibs/acre
b. Hemlock : 2,000 Ibs/acre
3. The amount of wood fiber that may be
decreased and still have the same effec-
tiveness when the wood fiber is com-
bined with chemical mulch is described
in Section 35.08, CHEMICAL
MULCH.
4. Information on the effectiveness of
wood fiber as a function of slope,
precipitation, and the amount of wood
fiber is provided in Table 16.
-------
Table 16. Test* of Wood Fiber Mulch Conducted Along California Highway* and in Hie Lake Tahoe Area. [15]
WOOD FIBER
Ibs/acre
3,000
2,000
1,000
2,000
1,000
3,000
2,000
1,000
DATE
Feb. 1973
to
Apr. 1973
»
tt
Apr. 1973
n
Apr. 1973
to
June 1973
rf
tt
LOCATION
App legate
Hwy 180
n
«i
Luther Pass
(Lake Tahoe)
It
King bury Grade
(Lake Tahoe)
«
tr
SLOPE
(HORIZ.:VERT.)
1:1
~-(cut)
R
n
1.5:1
(cut)
n
1.5:1 "
(fill & benched cuts)
n
n
PRECIPITATION
2.66"
(in 2 days) .
it
n
Very little.
«
Hone effective.
re
ti
Seedling No.
(per sq./ft. )
131
99
30
15
7
Few seedlings on
benched cuts
only.
n
n
Remarks
80$ of fiber retained.
Fiber washed from slope.
60$ of fiber retained.
Fiber washed from slope.
40$ of fiber retained.
Fiber washed from slope.
Seed and fiber remained in
place. Very little rain.
n
90$ of fiber remained on fill.
50$ " « " "' cut.
Windy site. Fiber blew away.
75$ of fiber remained on fill.
25% " " " w cut.
Windy site. Fiber blew away.
10^ of fiber remained on fill.
5% n " » « cut.
Windy site. Fiber blew away.
-------
75
35.07 WASHED DAIRY WASTE [12]
35.071 GENERAL
1. Washed dairy waste (WDW) is ma-
nure which has been washed from
milking parlors and pens.
2. WDW is applied with a hydroseeder.
3. The washed manure is screened to
remove most of the liquid and the result
is odorless and does not attract flies.
4. It is nearly as effective as wood fiber
and can be produced cheaply.
5. WDW is not commercially available at
this time.
35.072 APPLICATION
1. WDW shall be applied with a hy-
droseeder at a rate of 2,500 pounds per
acre in a slurry with water (3,000 gal-
lons per acre).
35.08 CHEMICAL MULCH
35.081 GENERAL
1. Chemical mulches are organic or plas-
tic and are sprayed on soils, forming a
crust. [37]
2. At the present state of the art most
chemical mulches are best applied as:
a. Temporary erosion control against
rain and wind, especially dust con-
trol.
b. Combination with wood fiber and
chemical mulch to reduce erosion
and develop vegetation.
3. Chemical mulches reduce the porosity
of soil, and this tends to inhibit the
growth of vegetation, especially under
conditions of low rainfall. [27] [37]
4. The crust formed by the chemical
mulch may be damaged by rodents,
deer and people traffic, and frost heave.
Proper traffic control would reduce the
damage to the crust by people and ani-
mals. The control of surface and sub-
surface drainage would decrease the
potential for frost heave which dam-
ages the crust.
5. If vegetation is to be established on
slopes using chemical mulch, wood fi-
ber must be added to hold the seed and
fertilizer. Information in Table 17
shows that chemical mulch without
wood fiber produced no seedlings. [16]
6. Compared to wood fiber alone, the
combination of wood fiber and chemi-
cal mulch would require less wood fiber
for equal effectiveness in erosion con-
trol.
35.082 APPLICATION
1. In vegetating a slope (unless extremely
steep and rocky), the seeds should be
applied first ,(see Section 22.40 Hy-
droseeding/Hydromulching), and then
covered with chemical mulch. [11]
2. For controlling wind erosion using
chemical mulch, refer to tests shown in
Table 18.
-------
76
Table 17. Erosion Control Tests With Chemical Mulch and Wood Fiber. [16]
Chemical Mulch
Soil Bond
kerospray 70
Crust-500
Ecology Control
Ibs/acre aj
200
200 plus fiber
120
120 plus fiber
180
110
110 plus fiber
200
100
100 plus fiber
200
300
Germination of Ryegrass
(seedlings/sq.ft. ) b/
0
5
0
4
0
0
8
0
0
4
0
0
Soil loss
(tons/acre)
12
10
12
13
8
16
12
45
12
25
28
aj Wood fiber (hemlock) was added at 1400 Ib/acre.
b_/ Slope of tests at 2:1.
Table 18. Experimental Tests of Chemical Mulches for Control of Wind Erosion Conducted by USDA, Agricultural Research
Service. [S\
Material aj
ORTHO Soil Mulch
Soil erosion Con-
trol Resin Ad-
hesive Z-3876
Anionic Asphalt
Emulsion
AGRI-MULCH
Technical Protein
Colloid 5-V
Elvanol 50-42
Aquatain
G-eon 652
Chemical Composition
Liquid, asphalt emulsion
Liquid, resin with main
component polyvinyl alcohol
Liquid, asphalt emulsion
Liquid, 63 percent
petroleum asphalt
Granular, protein colloid
15-16 percent U
Powder, polyvinyl alcohol
Liquid, sodium polypectate,
glycerin, and ammonia
Liquid, vinylchloride-
vinylidene chloride latex
Dilution
Ratio b/
1:1
1:2
1:1
1:1
1:10
1:80
1:5-5
1:20
Total Volume
(gal /acre)
1.,.362 -
1,712
2,452
1,907
128 ,
j
123
441
351
a/ These materials were effective in reducing wind erosion for at least 180 days
under agricultural conditions.
b/ Material to water ratio.
-------
77
35.09 WOOD EXCELSIOR
35.091 GENERAL
1. Wood excelsior consists of curled wood
fibers with approximate dimensions of
.02" X -04" X 8". (See Photo 20).
2. The fibers are randomly intertwined
and the resulting reinforcement pro-
vides an effective mulch material for
slopes and drainages.
3. Wood excelsior must be anchored by
staples or tackifier or netting on steep
slopes, drainages, and in windy areas.
4. Excelsior is available in rolls (4' X
180') with paper or plastic netting to
facilitate easier anchoring.
35.092 APPLICATION
1. Wood excelsior should be applied at 2
tons per acre. [27]
2. Wood excelsior applied with a mulch
blower should be anchored when slopes
exceed 3:1.
3. Asphalt emulsion when used for an-
choring should be applied at 200 gal-
lons per acre.
4. The mineral soil beneath the excelsior
should be visible when viewed from
above to allow vegetative growth.
Perry Y. Amimoto, California Division of Mines and Geology
Photo 20. Woods Excelsior Covered with Netting. (Nevada Co.)
X
w.«-,\
-
-------
78
35.10 FIBERGLASS
35.101 GENERAL
1. Fiberglass is made of inorganic materi-
als and will not rot, corrode, or burn.
2. It has the appearance similar to "angel
hair" used in Christmas decorations.
3. Fiberglass is available as matting in
rolls 1/2 inch thick and as loose materi-
al which is applied from compressed air
equipment.
4. Fiberglass matting is used as mulch
blankets, filters, and erosion checks.
5. Fiberglass as loose material provides an
effective mulch, especially when tacked
by asphalt or other tackifiers.
6. This type of mulch may not be pre-
ferred when the grass is to be mowed
due to possible inability of a mower to
cut fiberglass mixed with grass.
35.102 APPLICATION
1. Fiberglass as loose material may be ap-
plied as a mulch with compressed air
equipment at the rate of 35 pounds per
150-200 square yards.
35.11 JUTE
35.111 GENERAL
1. Jute netting is constructed of jute fibers
which are woven into a heavy jute mesh
with 1-inch by 1-inch spacings (Photo
21).
2. It is available in rolls 4 feet wide, 225
feet long, and weighs about 90 pounds.
3. Jute netting is principally used as ero-
i sion control on slopes of cut and fill and
1 along drainages.
4. Properly installed jute netting provides
high protection as mulch in establish-
ing vegetation.
5. Jute netting must remain in close con-
tact with the ground surface over the
entire slope to prevent erosion beneath
it.
35.112 APPLICATION OF JUTE NETTING
FOR DRAINAGEWAYS [21]
1. All trash and large stones shall be
removed from the site, and footprints,
ruts, tracks, etc., must be eliminated for
a smoothly graded channel.
2. The technique of jute installation is
shown on Figure 15.
3. At any point, erosion stops may be in-
stalled to check water flow and soil ero-
sion that may begin under the matting,
Spacings of erosion stops vary from 25
to 100 feet.
4. Where diversion terraces outlet into
waterway, the netting for the outlet is
laid first, so the netting in the main
channel will overlap the outlet strip.
5. To insure complete and continuous
contact between jute and ground sur-
face, the slope must be rolled after sta-
pling and seeding.
-------
79
5o/7 Conservation Service
Photo 21. Jute Netting on Cut Slope. (San Joaquin County)
-------
80
B.
A. Bury the top end of the jute strips In a
trench 6 Inches or more In depth.
Tamp the trench full of soil
Secure with row of staples,
10 inch spacing, *» inches
down from the trench.
x»i
**^» r*. "^^^J**
wR5S^xw
C. Overlap--Bury upper end of lower
strip as in 'A' and 'B1. Overlap
end of top strip A inches and staple
Erosion stopFold of jute
buried in slit trench and
tamped, double row of
staples.
inch
overlap of
jute strips
where two or
more strip
widths are
requi red.
Staples on
3' to 4'
centers.
Place staples
4 to 10 feet
apart.
TYPICAL STAPLES
#8 Gauge Wire
I
1
Figure 15. Detail for Stabilizing Waterway with Jute Thatching. [21]
-------
81
35.12 SOD [21]
35.121 GENERAL
1. Sod is applied where a quick cover is
needed to provide a vegetative filter
strip or to protect stockpiled material
or line a drainageway. (Photo 22).
2. Sod is expensive, but it may provide an
economical alternative in small areas of
onsite grading and where downstream
damages from sedimentation and tur-
bidity is high.
3. Cultivated sod is preferred over native
or pasture sod.
4. Sod should be free of weeds and un-
desirable coarse, weedy grasses.
5. Sod should be of uniform thickness, ap-
proximately 3/4 inch plus or minus 1/4
inch at time of cutting. (Excludes top
growth.)
6. Sod should have a compact root mat to
assure mechanical strength and to as-
sure early and firm anchoring to soil
surface. Broken pads and torn or unev-
en ends will not be acceptable.
\ i
7. Only moist, fresli sod should be used.
Sod should be harvested, delivered, and
installed within a period of 36 hours.
8. Site should be graded as needed to per-
mit the use of conventional equipment
for fertilizing and soil preparation.
35.122 SOIL PREPARATION
1. Fertilizers and other materials should
be added in accordance with soil test
information.
2. Harrow or disc the fertilizer and other
materials into the soil to a depth of 4
inches. Continue tillage until a reason-
able uniform, fine, firm seedbed condi-
tion has been attained. On sloping land,
the final harrowing or discing opera-
tion should be on the contour, where
feasible.
35.123 SOD PLACEMENT
1. Sod strips should be laid from the bot-
tom up, on the contour, and never up
and down the slope. On steep slopes,
the use of ladders will facilitate the
work and prevent damage to the sod.
During periods of high temperature,
lightly irrigate the underlying soil
slopes immediately prior to laying the
sod.
2. Place sod strips with tight joints, and
stagger the ends of joints.
3. Roll and tamp sod immediately, follow-
ing placement, to eliminate irregulari-
ties and to insure solid contact of root
mat and soil surface below. Do not
overlap sod. All joints should be butted
tight in order to prevent voids which
would cause air drying of the roots.
4. On sloping sites, secure sod to surface
soil with wood pegs, wire staples, or
split shingles (8 to 10 inches long by
3/4 inch wide).
5. Surface water cannot always be com-
pletely diverted from flowing over the
face of the slope, but a capping strip of
heavy jute or plastic netting properly'
secured along the crown of the slope
will provide extra protection against
lifting and undercutting of sod. This
same technique can be used to anchor
sod in water-carrying channels and
other critical areas. Use wire staples
only to anchor jute or plastic netting in
channel work.
6.
Immediately following installation, sod
should be watered until moisture pene-
trates the soil layer beneath sod to a
depth of 4 inches. Maintain optimum
moisture until the start of the rainy sea-
son.
7. If it becomes evident that portions of
the sodded areas have not rooted, these
areas shall be replaced with sod of the
same grass composition as originally
specified. Resodding shall be com-
pleted by the contractor within 7 days
following notification for repair by the
engineer (representing the permit-issu-
ing authority).
-------
USDA Soil Conservation Service
Photo 22. Sodded Storm Drain.
-------
83
35.13 BUILDING BLOCKS
Erodible soil on steep slopes may be stabil-
ized with building blocks. The holes in the
»
V* V
^-
blocks will allow vegetative growth because
of the protection against erosion provided
by the blocks. The blocks are aesthetically
pleasing as shown in Photo No. 23.
«. * ^ <. v
rik" * *. v>- «»iC
C *" %, -
,
^
. % ^
^
*
...«*-:%
*-^.rfi*
, 'HOaM **~ \*. «- ' * -
^^^fe; X^ *--."*'"
*> m"
m a*;-^W- -
&'
^,-
*
! 9%
Photo 23. Slope Protection with Building Blocks Placed in ai
Space Within the Blocks as Shown in Lower Photo. (Los Ang
. ....
Photo 23. Slope Protection with Building Blocks Placed in an Attractive Manner. Eventually, Vegetation Will Fill the
ithin the Blocks as Shown in Lower Photo. (Los Angeles Co.)
-------
85
Section 40
PROTECTION OF SLOPES AND
OTHER GRADED AREAS FROM RUNOFF
-------
87
41.00 TEMPORARY DIVERSION DIKE
A temporary diversion dike is a ridge of soil
constructed at the top of cut or fill slopes to
divert overland flow from small areas and
prevent their runoff on the slopes. The daily
construction of temporary diversion dikes
during construction will greatly reduce ero-
sion from unexpected runoff. (Photo 24, Fig-
ure 16).
41.10 DESIGN CONSIDERATION [41] [57]
1. Minimum ridge height: 1.5 feet.
2. Minimum top width: 2 feet.
3. Maximum side slopes: 2:1.
4. Material shall consist of compacted soil
except as in item 7.
5. All diversion dikes must have a positive
grade draining to a stabilized outlet.
6. Runoff must be diverted to a stabilized
undisturbed area, a prepared level
spreader, or into a slope protection
structure (culvert, downdrain, etc.)
7. In wooded areas, where top of slope ac-
cess is limited, diversion dikes can be
constructed as a dozer finishes the slope
by carrying soil unslope and dumping it
at crest. Soil compaction of the dike is
not possible in this instance.
Photo 24. Embankment Erosion That
Would Have Been Prevented by the Use of
Diversion Dikes. (Yolo Co.)
Perry Y. Amimoto, California Division of Mines and Geology
-------
88
Figure 16. Temporary Diversion Dike. [41]
-------
89
42.00 PERMANENT DIVERSION DIKE
A permanent diversion dike is a ridge of non
-credible material usually applied on roads
to prevent roadway drainage from flowing
over the road fill (Photo 25).
42.10 DESIGN CONSIDERATION
1. A permanent diversion dike should be
resistant to erosion from concentrated
runoff and be of sufficient height to pre-
vent overtopping.
2. Permanent diversion dikes are generally
constructed of asphalt.
3. The dikes should have nonerodible dis-
charge outlets or outlets with energy dis-
sipating structures.
*
" i.«.
Placer County Department of Public Works
Photo 25. The Permonent Dikes on Each Side of the Road Guide the Runoff to a Drain Outlet. (Placer Co.)
-------
9i
43.00 INTERCEPTOR DITCH
Interceptor ditches are permanent structures
located on top of a cut slope that divert
drainage away from the slope of the cut
(Photo 26).
43.10 DESIGN CONSIDERATION
1. The interceptor ditches should convey
the design flood from the tributary area
above the cut.
2. The interceptor ditches should be pro-
tected against erosion by lining and also
protected against clogging by vegetative
debris which should be removed regular-
ly.
3. The discharge area should be non-erodi-
ble or have energy dissipating structures.
4. The interceptor ditch should be com-
pleted before the cut is made to the final
grade.
California Division of Resource Conservation
Photo 26. Erosion Control of a Cut Slope by a Lined Interceptor Ditch and Revegetation. (Nevada Co.)
-------
91
44.00 SLOPE DRAIN
Slope drains (down drains) are temporary or
permanent conduits which convey drainage
from slopes to stable points of discharge be-
low. The drains may be a flexible down
drain, pipe drop, or chute (flume).
The drains should be installed immediately
after completion of the cut or fill and before
revegetation of the slopes. Photo 27 shows
the erosion of a fill which could have been
prevented by a slope drain.
Perry Y. Amimoto, California Division of Mines and Geology
Photo 27. Lack of a Slope Drain and an Energy Dissipator Caused the Erosion of this Road Fill. (Humboldt Co.)
-------
92
44.10 FLEXIBLE DOWN DRAIN [57]
A flexible down drain is a flexible conduit of
heavy duty fabric or other material which is
to be used as a temporary slope drain. (Fig-
ure 17)
44.11 DESIGN CONSIDERATION
1. The flexible down drain is placed on a
firm foundation such as undisturbed soil
or well compacted fill.
2. The diameter should be sufficient to con-
vey the maximum runoff expected dur-
ing the life of the drain.
3. Flexible conduit should be secured to ex-
tension collar with securing straps of
fabric, metal, etc., secure in at least one
corrugation of extension collar.
4. Down drains should be anchored with
metal "T" pins spaced every twenty feet
to eliminate dragging and wind whip-
ping.
5. Down drain should convey water to a
stabilized outlet.
44.12 MAINTENANCE
1. Inspect for damage or clogging after
each storm.
2. In below-freezing weather, check to en-
sure that sides of collapsed down drain
are not frozen together.
3. Do not allow placement of any material
on collapsed down drain.
4. Anchors should be resecured as neces-
sary.
-------
93
Perry Y. Amimoto, California Division of Mines and Geology
Figure 17. Flexible Downdrain. [57]
-------
94
44.20 PIPE DROP [21]
Pipe drops are temporary or permanent
pipes placed on cut or fill slopes as outlets for
diversion dikes and interceptor ditches.. (Fig-
ure 18).
DESIGN CONSIDERATION
1. Pipe drops shall have a capacity ade-
quate to carry the design flood.
2. A water depth of 1.8 times the pipe di-
ameter above the pipe inlet invert is re-
quired for full pipe flow.
3. The dike height above the pipe inlet in-
vert shall be adequate to contain a water
elevation sufficient for full pipe flow plus
an allowance of at least 0.5 feet for free-
board.
4. The pipe shall be of the required strength
and durability.
5. The pipe shall be imbedded in the em-
bankment to a depth that will prevent
movement of the pipe.
6. Measures to prevent soil erosion shall be
installed at the inlet and outlet.
44.30 CHUTE (FLUME) [41]
A chute or flume is a high-velocity, open
channel for conveying water to a lower level
without erosion. (See Photos 28 and 29).
44.31 DESIGN CONSIDERATION
1. The structure shall be placed on a firm
foundation such as undisturbed soil or
well compacted fill.
2. Specific design considerations are shown
in Figure 19 - Chute (Flume) and Table
19 - Dimensions for Chute shown in
Figure 19.
max. water
surface
2 min.
Undisturbed soil
or compacted fill
PROFILE
min slope 1.0%
max slope 3:1
slope
Riprap is 6 layer
of 4* min. rock(or
rubble with 3"sand
bedding
Figure 18. Pipe Drop. [21]
-------
95
USDA Soil Conservation Service
California Division of Resource Conservation
USDA Soil Conservation Service
Photo 28. Slope Drain (Down Drain) Systems. Upper Left Photo Shows Intake to a Pipe Drop Protected by a Sediment Trap. Lower Left
Photo Shows Erosion Caused by Poor Design in Which the Flow Exceeded the Capacity of the Corrugated Channel. Photo on Right Shows
a Temporary Asphalt-Lined Chute.
-------
96
Perry Y. Amimoto, California Division of Mines and Geology
Photo 29. A Metal Chute (Flume) Protecting Road Fill.
-------
97
Top of earth dike &
top of I ining
Slope varies, not
.steeper than 1.5:1
& not flatter than
20:1
Dimen-
sion
1.5'
Energy dissipator is
concrete building blocks
L, f_ »J on edge anchored to I ining
Undisturbed-soi I or
compacted fill
Place 3" layer of sand
for drainage under outlet as shown
for ful I width of structure
Riprap Is layer of
rocks or rubble
Toe of slope
Size Group
B
2.0'
10"
PLAN VIEW
mm
SECTION B-B
Notes: ~~
1. Lining shall be Portland Cement concrete, bituminous concrete or comparable
material.
2. Some type of energy dissipator, such as the one shown above, must be used to
prevent erosion at the outlet.
3. The size is designated with a letter and a number, such as A-6, which means
Size Group A with a 6 ft. bottom width (b). For structure dimensions, see
table in upper right hand corner.
U. S. DEPARTMENT OF AGRICULTURE
SOIL CONSERVATION SERVICE
College Park, Md.
GRADE STABILIZATION
STRUCTURE
(Chute or Flume)
MD-SCS DESIGN
STANDARD
G.S.S.-1
Figure 19. Chute (Flume). [41]
-------
98
Table 19. Dimensions for Chute Shown in Figure 19. [41]
The chutes or flumes are divided into two size groups as follows:
Size Group A
1. The height of the dike
2. The depth of flow down
3. The length of the inlet
Size Group B
1. The height of the dike
2. The depth of flow down
3. The length of the inlet
Each size group has various
Bottom
Size I/ Width, b,
(feet)
A-2 2
A-4 4
A-6 6
A-8 8
A-10 10
_!/ The size is designated
or flume in Size Group
If a minimum of 75% of the
the life of the structure,
at the entrance (H) equals 1.5 feet.
the chute (d) equals 8 inches.
and outlet sections (li) equals 5 feet.
at the entrance (H) equals 2 feet.
the chute (d) equals 10 inches.
and outlet sections (L) equals 6 feet.
bottom widths and allowable drainage areas as shown below:
Maximum . Bottom
Drainage Size I/ Width, b
Area (acres) (feet)
5 B-4 4
8 B-6 6
11 B-8 8
14 B-10 10
18 B-12 12
with a letter and a number, such as A-6
A with a 6 foot bottom.
drainage area will have a good grass or
the drainage areas listed above may be
Maximum
, Drainage
Area (acres)
14
20
25
31
36
which means a chute
woodland cover throughout
increased by 50%.
-------
99
45.00 DIVERSION
I
A diversion is a temporary or permanent
structure consisting of a channel or ditch and
a ridge constructed across a sloping land sur-
face on the contour or with predetermined
grades to intercept and divert surface runoff
before it gains suffcient volume and velocity
to create erosion. The water is collected and
conveyed laterally along the diversion at
slow velocity and discharged into a protected
area or outlet channel. See Photo 30.
45.10 DESIGN CONSIDERATION [21] [23]
1. The number of diversions and the
physical extent and spacing is depend-
ent upon the land slope, soil, and run-
off.
2. Diversions should not be established on
slopes exceeding 15%. [23]
3. The dimensions of a diversion are
shown in Figure 20. - Diversions.
4. All ditches or gullies which must be
crossed will be filled and compacted
prior to or as part of the construction.
5. Vegetation is to be removed and the
base thoroughly disced before place-
ment of fill.
6. Permanent diversions are not applica-
ble below areas that produce large
amounts of sediment unless land treat-
ment practices or structural measures
designed to prevent damaging accumu-
lations of sediment in the channels have
been installed with or before the diverr
sions. !
7. For permanent diversions, a filter strip
of close growing grass shall be main-
tained above the channel. The width of
the filter, measured from the center of
the channel, shall be one-half of the
channel width plus fifteen feet. The di-
version ridge and channel are to be
seeded to grass to prevent soil erosion.
8. Permissible velocities should be as
shown in Appendix II D, Allowable
Velocities for Unlined Earth Channels.
Higher velocities may be allowed if
adequate vegetation can be established
before runoff flows in the diversions.
9. Diversions shall have the capacity so as
to convey the design flow as estimated
by hydrologic methods such as shown
in Appendix II D.
10. The shape of the channel cross section
shall be such that the diversion can be
maintained with modern equipment.
11. The downslope ridge is to include a set-
tlement factor during design.
12. Diverted runoff should outlet into a
stabilized undisturbed area, a prepared
level spreader, or into a slope protec-
tion structure.
-------
100
State Water Resources Control Board
USDA Soil Conservation Service
Photo 30. Diversions Should b« Constructed in the Large Graded Area Shown in the Top Photo and Lined, if Necessary, as Shown in the
Lower Photo.
-------
101
Top width 4 ft. min.
Height 1.5* min. unless otherwise noted on the plans (measured from the slope toe
of the ridge).
Side slopes 3M maximum (flat enough to allow construction traffic to cross if
desired).
Grade 0.5% to 1.0%
Spacing 20Oto300 feet between diversions. (The steeper the slope, the closer
the spacing should be).
Filter strip 1/2 of channel width plus 15 feet.
FOR USE ON DRAINAGE AREAS OF 5 ACRES OR LESS. LARGER AREAS REQUIRE A
DIVERSION DESIGN.
figure 20. Diversion.
-------
103
Section 50
ROADWAY
PROTECTION
-------
105
51.00 INTERCEPTOR DIKE [41]
An interceptor dike is a temporary ridge of
compacted soil constructed normal to the
slope or graded right-of-way and is used to
intercept and convey surface water at
nonerosive velocities to an adequate and sta-
ble outlet (Figure 21).
It is a temporary structure which may be
designed for construction traffic to cross. It
should be inspected after each rain and re-
paired before the next storm.
51.10 DESIGN CONSIDERATIONS
1. Minimum ridge height: 1.5 feet.
2. Minimum top width: 2 feet.
3. Maximum side slopes: 2.1 (Horizontal-
Vertical) .
4. Maximum allowable spacing between
dikes ranges from 200 to 300 feet. Spac-
ings may also be determined by Tables
21 and 22 on cross drain spacings.
5. Dike material shall consist of compacted
soil.
6. Interceptor dikes should have a positive
grade draining to a stabilized outlet. :
7. Diverted runoff shall outlet to a stabil-
ized undisturbed area, a prepared level
spreader, or into a slope protection
structure (culvert, down drain, etc.)
8. Interceptor dikes can be installed by a
road grader or angle blade dozer.
Figure 21. Interceptor Dike. [41]
-------
106
52.00 DRAINAGE DIP [29]
A drainage dip or intercepting dip is a tem-
porary or permanent structure constructed
across a graded right-of-way and is designed
to reduce erosion by intercepting storm run-
off and diverting it where it can be disposed
of with minimal erosion. They are broad and
shallow and are designed to allow vehicles to
pass over them during and after construction
activities. (Figure 22)
52.10 DESIGN CONSIDERATIONS
1. A minimum of 50 feet on the uphill ap-
proach slope is required. (Figure 23)
2. A minimum of 15 feet on the slope leav-
ing the dip is necessary to minimize the
vehicle jolt and to prevent wheel tracks
from channeling flood water down the
roadway.
3. Where outsloped, spillway openings two
feet wide on the bottom shall be left
through the raised shoulder.
4. Inslope drainage is conveyed to the
downhill side of the road through a cul-
vert.
5. Dips are not recommended on roads ex-
ceeding 10 percent grade.
6. Dip is installed below outcurves, above
incurves, and through fills and elsewhere
as needed on outsloped or insloped sec-
tions of the road.
7. The centerline or hydraulic bottom is at
an angle of 45-60 degrees with the cen-
terline of the road to minimize vehicle
jolt and so that the hydraulic bottom will
have a grade of about two percent more
than the original grade of the road.
8. A raised shoulder or berm is necessary to
retain the water under control until it
reaches the hydraulic bottom of the dip.
9. Slow-curing asphalt mix is commonly
used for forming berms, outlets, and
spillways.
-------
107
MIN.C*
ENTIRELY IN
SOLID OROUNO
CROSSXSECTION ON
Figure 22. Drainage Dip. [29]
-------
/,45°IF POSSIBLE BUT
NOT LESS THAN 30°
SHOULDER BERM-18 HIGH
METAL SPILLWAY TO BE USED WHERE DIP DOES NOT
DISCHARGE UPON ROCK, CENTER SPILLWAY ON HYDRAULIC
"BOTTOM a FLUME TO DISCHARGE ON ROCK OR OTHER
PROTECTION.
PLAN
OR.G.NAL R_OAD_GRADE_ __^_
Z(DEPTH BELOW HORIZONTAL)
PROFILE-UPPER SIDE
NOTES:
I. CROSS GRADE OF DIP MUST BE 2% GREATER THAN THE ORIGINAL ROAD GRADE
2. DISTANCE "X" AS FOLLOWS:
ROAD GRADE FROM 0% TO 5% "X1 = 50 FT.
ROAD GRADE ABOVE 5% ADD 5 FT. FOR EACH U IN EXCESS OF 5%
3. DISTANCE "Z" AS FOLLOWS:
THIS IS A MAXIMUM OF k INCHES ON A ROAD GRADE OF 5% OR LESS,
DECREASING TO ZERO ON A 10% GRADE
DIP TO BE ROUNDED FOR RIDING COMFORT
4. DIP NOT RECOMMENDED FOR ROAD GRADES OVER 10%
Figure 23. Drainage Dip (Profile). [29]
-------
109
53.00 SIDE DITCH
Side ditches adjoin the shoulder of a road
and prevent uncontrolled runoff on the road-
ways (Photo 31).
Side ditches, which are either lined or un-
lined, should have the capability to provide
capacity for runoff, resist erosion, and[ pre-
vent sedimentation. (Photo 32) ~
53.10 LINED SIDE DITCH
1. For lined side ditches using rock, con-
crete, or vegetation, refer to Section 60,
Channel Protection.
2. The "Planning Manual" by the Califor-
nia Division of Highways has design de-
tails on concrete lined side ditches. [35]
53.20 UNLINED SIDE DITCH
1. For limiting water velocities on unlined
side ditches, refer to Appendix II D,
"Allowable Velocities for Unlined Earth
Channels." Higher velocities may be al-
\
lowed if adequate vegetation can be es-
tablished before runoff flows in the side
ditch.
2. For unlined but vegetated side ditches,
with the flat area two feet or more in
width, provide greater traffic safety, per-
mit more effective seeding, and less
maintenance than V-bottom ditches.
3. Water velocities may be retarded by ero-
sion checks or dams. Spacing of checks
as a function of grade is shown on Table
20, "Spacing of checks in roadside dit-
ches".
54.00 OPEN-TOP CULVERT
Open-top culverts are culverts without the
enclosure, and thereby serve to intercept
road surface runoff as well as convey collect-
ed runoff across the roadway.
54.10 DESIGN CONSIDERATION
The design of open-top culverts is described
,in Section 81.90, Open-Top Culvert. I
-------
110
California Divition of Resource Conservation
"- "f
4, - iV.SKJ* .'
USDA Soil Conservation Service
Photo 31. Lined Side Ditches. Rock-Lined in Upper Photo and Asphalt-lined in Lower Photo.
-------
Ill
California Division of Resource Conservation
'-*H, '
'"«SS^X
^HlC*' ' i
\
&*; - ^
1
USDA Soil Conservation Service
Photo 32. Erosion and Sediment Problems of Unlined Side Ditches. Upper Photo Shows Erosion Along the Roadside, and the Lower
Photo Shows a Culvert Filled With Sediment.
-------
Table 20. Spacing of Check* in Roadside Ditches. [29]
Percent
ditch
grade
3
4
5
6
7
8
9
10
11
12
13
14
15
Distance between checks
2$
Feet
150
75
50
37
30
24
21
18
16
15
13
12
11
Checks
Final
Feet
_
150
75
50
37
30
24
21
18
16
15
13
12
18 inches high
ditch grade
4$
Feet
_
-
150
" 75
50
37
\ 30
\ 24
--21
18
16
15
13'
<>*
Feet
-
-
150
75
50
37
30
24
21
18
16
15
2fo
Feet
* 100
50
33 ^
25
20
16
14
12
11
10
9
8
7
Checks 12
.Final
3^
Feet
_
100
50
33
25
20
16
14
12
11
10
9
8
inches high
ditch grade
4fo
Feet
_
loo
50
33
25
20
16
14
12
11
10
9
5%
Feet
_
_
100
50
33
25
20
16
14
12
11
10
-------
113
Section 60
CHANNEL PROTECTION
-------
115
61.00 VEGETATIVE LINING
Vegetative lining consists of grass or woody
plants which line the waterways. Vegetative
lining reduces the erosion along the channels
and provides for the filtration of sediment.
Also, vegetative lining gives an aesthetically
pleasing appearance, and improves wildlife
habitat (See Photos 33 and 34).
61.10 GRASS LINING
1. The type of grass to line the channels
may be based on native grasses along the
streambanks and drainageways within
the project area or on the types of vegeta-
tion listed in Section 20, Establishment
of Protective Vegetation.
2. Sod may be used if vegetative protection
is immediately required. Sod application
is described in Section 35.12.
3. The slopes of the streambanks or drain-
ageways shall not exceed 4:1 if the grass
is to be mowed [57].
4. The design velocity shall not exceed four
feet per second. [57]
5. Jute netting, fiberglass netting, and
mulch blankets described in Section 30,
Surface Protection with Mulches and
Other Materials, may be used to provide
temporary erosion control until vegeta-
tion is established.
i
Photo 33. Grass-Lined Diversion Terrace Which Prevents Sediment From Entering Storm Sewer.
USDA Soil Conservation Service
-------
116
USDA Soil Conservation Service
J/
/
««
*. < <
»
Photo 34. This Channel is Lined With Grass on the Left Bank and With Rock on the Right Bank.
-------
117
61.20 LINING WITH WOODY PLANTS [52]
1. The procedure for establishing woody
plants is the following:
a. Plant native tree willows in silt
deposit and at an approximate spac-
ing of 3' by 3'.
b. Plant either rooted plants or cut-
tings made from healthy young wil-
low trees.
c. Keep young trees within one foot of
normal water line of stream.
2. Maintenance
a. Cut trees when they reach six to
eight inches in diameter. Leave three
foot stumps.
b. Replace plants that die or get
washed out.
c. Keep channel clear of debris. Rein-
force weak points.
62.00 FLEXIBLE LINING
Flexible linings are formed of individual
pieces of materials such as rock, gabions, and
old tires. Flexible linings have the advantage
of adjusting to differential settlement along
the lined channel while still providing pro-
tection against erosion along the channels.
62.10 ROCK LINING
1. The minimum rock diameter when ran-
domly-placed on rock-lined drainages
may be determined by Appendix II D,
Allowable Velocities for Unlined Earth
Channels (See Photo 34).
2. Information on the specifications of
shape, specific gravity, soundness, and
resistance to abrasion of rock are in the
USDA - Soil Conservation Service, Na-
tional Engineering Handbook. [49]
-------
118
Perry Y. Amimoto, California Division of Mines and Geology
-
Y-C/^-
^>* *r, l
"*>^5
Photo 35. Gabion Employed for Slope Protection. (Mendocino Co.)
-------
119
62.20 GABIONS [18]
\
Gabions are rock-filled, galvanized steel
wire cages which when wired together form
large, flexible, permeable protective blocks.
(See Photo 35).
Relatively small rock fragments or gravel 4
to 8 inches in diameter can be used to form
a coherent structure capable of streambank
protection.
Flexibility of gabions permits them to with-
stand differential settlement without frac-
ture.
Permeability of gabions prevents hydrostatic
heads from developing behind structure.
62.30 OLD TIRES [2]
Old tires, joined together by steel cables or
bands, can form an effective protective lining
against erosion of a streambank (Photo 36).
Not only do the tires provide streambank
protection, but after they collect silt and
become permanently imbedded, the tires
protect the roots of vegetative cover.
The advantages of old tires as protective lin-
ing are low cost of installation and maintain-
ing the aesthetic view of vegetative cover
along streambanks.
Approximately 5,000 tires per acre will be
needed. Panels of tires measuring eleven tires
across and six tires high have been lowered
by A-frame onto the streambank (Photo
37).
Old tires should not be used if siltation and
revegation within the tires are not likely to
occur.
-------
U.S. Bureau of Indian Affairs
Photo 36. Old Tires Used for Streambank Protection. The Lower Photo Shows How Well Vegetation Has Grown Within the Tires.
-------
121
.
"-.fete-
U.S. Bureau of Indian Affairs
Photo 37. Old Tires Lifted by A-Frames and Lowered Onto the Streambank.
-------
122
63.00 RIGID LININGS
Rigid linings are nonflexible material which
are used to line the channels. Rigid linings
provide the maximum flow capacity due to
its low roughness coefficient. Asphalt, con-
crete, grouted rock, sacked concrete and soil
cement form rigid linings.
63.10 DESIGN CONSIDERATIONS
1. Rigid linings require a firm, highly com-
pact, stable foundation and careful con-
struction.
2. Rigid linings must be carried below
channel bottom to prevent undercutting
unless riprap protection is provided
along the toe.
3. When smooth channel linings, such as
concrete, are to be constructed, the de-
signer should consider the increased run-
off rate likely to occur downstream.
4. Rigid channels should be protected
against destruction by frost action, uplift
pressures or by water overtopping the
channel sides or leaking through the
joints and washing away the supporting
soil.
-------
123
Section 70
GRADE CONTROL AND
REALIGNMENT OF CHANNELS
-------
125
71.00 CHANNEL GRADE CONTROL
Grade control measures are structures which
reduce and maintain the channel gradients.
By reducing the channel gradient, the runoff
velocities decrease, thus preventing erosion
. at higher flows. Such structures include
check dams, drop structures, and erosion
stops (erosion checks).
71.10 CHECK DAMS [57]
1. General
a. Check dams are structures used to
stabilize the grade and control head
cutting in natural or artificial chan-
nels (Photos 38 and 39).
b. Check dams prevent excessive ero-
sion by reducing flow velocities in
watercourses and by providing par-
tial lined channel sections or struc-
tures that can withstand high flow
velocities.
c. Formal design is generally required.
2. Specification
a. Overfall structures of concrete, met-
al, rock, gabions, wood, etc., may be
used in the construction of check
dams.
b. Site should be in a reasonable
straight channel section.
c. Site and foundation conditions and
aesthetic considerations are impor-
tant factors in material selection.
d. Channel grade above and below the
structure should be evaluated to de-
termine if erosion, sediment deposi-
tion or flooding will be a problem.
-------
126
Perry Y. Amimofo, California Division of Mines and Geology
Photo 38. Check Dams. Upper Photo Shows Check Dam in on Unlined Channel.
USDA Soil Conservation Service
-------
127
»
: .j
V
^
\ _ .-. V ~"
'"~~
'
USDA Soil Conservation Service
Photo 39. Check Dam Constructed of Concrete Building Blocks.
-------
128
71.20 DROP STRUCTURES [491
1. General
a. Drop structures are weir structures
in which water flow passes through
a weir opening, drops to an approxi-
mately level apron or stilling basin,
then passes into the downstream
channel.
b. Drop structures are used to control
gradient in natural or constructed
channels, control tail water at the
outlet of a spillway or conduit and
serve as reservoir spillways.
c. The drop spillway may be more cost-
ly than some other types of struc-
tures where the required discharge
capacity is less than 100 cfs and the
total head or drop is greater than 8
or 10 feet.
2. Specification
a. Detailed specifications on drop
structures are in the USDA Na-
tional Engineering Handbook, Sec-
tion 11. [49]
71.30 EROSION STOP (EROSION CHECK)
[57]
1. General
a. Erosion stops consist of porous, mat
-like material installed in a slit
trench that is oriented perpendicular
to the direction of flow in a ditch or
swale.
b. Provides positive grade control of
shallow, unlined drainageways.
c. Prevents formation of rills and gul-
lies by permitting subsurface water
migration without the removal of
soil particles.
d. They can also be used on critical
slopes where severe sheet flow prob-
lems may occur.
e. Material - flexible, porous, long-
lived mats of fiberglass, plastic, jute,
etc.
2. Specification
a. Installed immediately downstream
from every tributary discharge
point.
b. Installed at each point of change in
gradient (steep to shallow and shal-
low to steep).
c. Installed at 20 - 75 foot centers de-
pending on slope, soil type, etc.
d. Installed at least three inches below
the maximum depth at any existing
rill or gully and eight to twelve
inches deep in newly-graded areas.
e. Lateral extent to an elevation at least
six inches above the design flow ele-
vation to protect against rill forma-
tion during intense runoff events.
f. Anchor with staples in bottom and
on vertical side of slit trench on 24-
inch centers.
g. Trench must be backfilled and com-
pacted, reseed disturbed area.
h. A cap strip should extend two feet
upstream and downstream of the
erosion check. Stagger staple on six
to nine inch centers along the ero-
sion check.
i. Install immediately after final grad-
ing and before seeding.
j. Inspect for erosion and replace or re-
pair where necessary.
72.00 CHANNEL REALIGNMENT
Channel realignment is a structural measure
which alters the existing course of a water-
way. Channel realignment is instituted when
the stability of the natural channel is not
feasible under existing or new runoff.
o
72.10 DESIGN CONSIDERATIONS [62]
1. When channel changes are necessary,
the existing channel for one-half mile or
more upstream should be examined with
particular attention given to the material
-------
within the channel and its susceptibility
to erosion, in order to attempt prediction
of the reaction after construction.
2. The engineer should attempt to dupli-
cate the hydraulic properties of the natu-
ral stream in the relocated section.
3. Since significant steepening of the chan-
nel grade will usually result in degrada-
tion, every effort should be made to
approximate the slope of the natural
channel through the channel relocation,
and eliminate the possibility of supercrit-
cal flow. For long channel relocations,
this might be accomplished to some ex-
tent by the introduction of artificial
channel meanders.
129
4. Another possible solution for channel
relocations of small streams carried un-
der the highway in a drainage structure
is to place the stream on its natural slope
upstream and downstream of the struc-
ture. The additional drop created by the
shortening of the natural channel can be
taken up in the design of the drainage
structure.
5. In some cases, it may be desirable to
build a drop structure in the relocated
channel of streams to avoid severe steep-
ening of the channel slope. However, use
of drop structures should be approached
with caution because of their vulnerabili-
ty to damage at times of unusual flood-
ing and because of the hydrologic effect
on aquatic life.
-------
131
Section 80
INSTALLATION OF CULVERTS,
PAVED FORDS, BRIDGES
-------
133
81.00 CULVERTS
A culvert is a conduit used to provide free
passage of surface drainage water under a
highway, canal, or other embankment. The
conduits are usually constructed of corrugat-
ed metal or reinforced concrete pipes. Open-
top culverts consisting of box-like frames in-
stalled flush with the road surface are used
on very low traffic, unpaved roads.
81.10 DESIGN CONSIDERATIONS
1. The factors to consider in the design of
culverts are culvert alignment, culvert
grade, culvert capacity, debris control,
and energy dissipation. Failure to prop-
erly consider these factors are primarily
responsible for the failure of culverts
(Photo 40).
2. The "California Culvert Practice", a
manual published by the California Di-
vision of Highways, is suggested as a ref-
erence for the design of culverts. [32]
3. Formal design of peak runoff values is
required. Use accepted methods or
method in Appendix II C, Determining
Rate of Rainfall Runoff.
81.20 CULVERT ALIGNMENT [29]
1. First principle of culvert alignment is to
provide the water with a direct entrance
and a direct exit.
2. Avoid sharp turns at the inlet channel as
it may cause erosion or blocking of the
inlet by debris.
3. Abrupt changes in line of flow which
tends to retard velocity should be avoid-
ed.
4. Realignment of a natural channel to per-
mit installation of culverts at right an-
gles to road centerline is likely to cause
erosion problems.
5. A sharp turn in the inlet channel is also
likely to result in blocking the inlet by
deposition or debris.
6. Examples of suggested culvert-channel
alignment configurations are shown in
Figure 24.
81.30 CULVERT GRADE
1. The culvert grade should be at least one
or two percent more than the channel or
waterway entering the culvert.
2. Generally, a ten percent grade will pre-
vent deposition of a sediment ranging
from fine sands to rocky materials.
3. Figures 25 to 26 show the proper layout
of culverts as a function of the ground
slope and type of culvert.
81.40 CULVERT CAPACITY
1. Many drainage structures are designed
for ten-year flood stages (Figure 27, En-
trance Head vs. Flood Stage).
2. When higher stages above the 10-year
flood state occurs, then the full capacity
of the culvert may no longer be con-
trolled solely by the size of the entrance.
3. The design for full capacity must consid-
er the culvert grade, culvert capacity, in-
let and outlet velocities, head, and
freeboard.
-------
134
C. Forrest Bacon, California Division of Mines and Geo/
ogy
Photo 40. Culvert Pipe Plugged With Sediment Causing Overtopping and Roadway Washout. (Siskiyou Co.)
-------
135
Old
Chonn
Domi
New Channel
(a) and (b) Channel Changes Improve Alignment
Pavement
or TrocN
(c)
Dam
Old Channel
\ s^^"Re!ocafion
*" * **
(e) Stream should pass
under the road at first
opportunity.
(f) Broken-back align-
ment. Desirable in some
cases.
Figure 24. Culvert Alignment. [29]
-------
136
Final grad
after settlement
(o)"Camber"under high fills
Paved spillway
(e) Hillside grades; erosion prevention
WRONG
x Sediment
Improved grade
Stream grade
(b) Anticipating Sedimentation
WRONG
Reduced
waterway,
Sediment
Possible erosion*
(c) Change from channel grade may
cause sedimentation or erosion
Water
WRONG
Reduced waterway
(d) Culvert placed below proper grade;
waterway Is reduced.
Transition
Joint
*Pipe spillway
(g) Hillside grades; erosion prevention (g) "NOTE: From the transition joint in the
pipe spillway a smaller diameter pipe
i ; will handle the required volume because
the gradient has been increased. Refer
to Pipe Drop, Sec. kk.2Q, ,
Rip-rap
(h) Cantilever
Figure 25. Guidelines on Culvert Grades. [29]
-------
137
METHOD No.
I k to I Slope
Side Slope
0% to 30%
Method 1. Where side slopes are from
0 to 30 percent, lay pipe along the
natural ground slope in the drainage
course. This method will also be used
on steeper slopes where a running stream
is encountered and where installation
cost would prohibit the use of either
of the two following methods.
METHOD No.2
Pipe placed on
10% grade
Side Slope
31% to 50%
Method 2. Where side slopes are from
31 to 50 percent, lay the pipe through
the fill on a grade of 10 percent and
carry the water down the fill slope in
a method where running streams interfere
with the installation or where the pipe
can be laid on a skew to carry the water
along the natural ground from the lower
edge of the pipe to the original drain-
age channel. The most economical method
should be used; in some cases it will be
cheaper to protect the lower portions of
the fill from wash than to extend the
pipe to the toe of the slope.
METHOD No. 3
Side Slope
51% 8 Over
Method 3. Where side slopes are in
excess of 50 percent, either lay pipe
through the fill on a 10 percent grade
and protect the lower portion of the
fill from wash by a hand-placed rock
wall, or skew the pipe so the discharge
will fall on the natural ground and be
carried to the original channel in open
ditch.
Figure 26. Additional Guidelines for Culverts Under Fills. [29]
-------
138
IOO-Year stage
10-Year stage
(a) Current Practice: Frequent flood just fills the entrance
100-Year stage.
(b) Balanced Design: Infrequent flood submerges entrance
Figure 27. Entrance Head vs. Flood Stage. [32]
Perry Y. Amimoto, California Division of Mines and Geology
Photo 41. Spillway of Culvert Lined With Cemented Rock. (Yolo Co.)
-------
139
81.50 DEBRIS CONTROL DEVICE [32]
1. Debris control measures should be con-
sidered an essential part of culvert de-
sign, to be developed prior to
construction.
2. Debris barrier types should be selected
and adapted in accordance with the ex-
pected debris such as floating debris
(limbs, logs, refuse, tules) and detritus
(clay, silt, sand, gravel, boulders, large
rock fragments).
3. Debris control devices should be cleaned
and regularly maintained.
81.60 CULVERT RISER
1. Culvert risers permit inlet areas of cul-
verts to serve as temporary or permanent
sediment traps in the same manner as
sediment detention basins. (Figure 28).
2. As the runoff water pools up behind the
embankment, the sediment settles out.
3. Culvert risers may consist of a perforat-
ed metal pipe attached to the inlet of the
drainage culvert and extending upward.
4. For the proper design of risers, see Sec-
tion 90, Sediment Traps and Detention
Basins.
5. Seep collars should be included in cul-
vert design if it is determined that the
failure hazard by annular seepage is
high.
Figure 28. Culvert Riser. [31]
-------
140
81.70 DROP INLET [29]
1. Drop inlets reduce the discharge velocity
from the culverts by lowering the culvert
flowline gradient and by energy dissipa-
tion.
2. Drop inlets reduce the erosion along the
inlet channels.
3. They serve as catch basins when water is
collected from a flat area without a defi-
nite channel.
4. Sidewalls may be of masonry, prefabri-
ated metal, prefabricated concrete pipe,
or cast-in-place concrete.
5. Precast concrete or prefabricated metal
manholes may be substituted for built-in
drop inlets.
6. Drop inlets may be rectangular or circu-
lar (Figure 29).
7. A riser and debris barrier above the inlet
may be necessary (Figure 29).
8. Periodic cleaning and inspection after
each storm will be necessary.
DROP INLET FOR USE WITH
STANDARD PIPE CULVERTS
\
May be circular \
Metal debris riser placed over entrance in debris basin
20
Culvert Pipe
0s Inside Diameter of Culvert
Pipe ( minimum 18")
PLAN
oulder
ELEVATION
Figure 29. Drop Inlet. [29]
-------
141
81.80 DISCHARGE APRON [29]
1. Discharge aprons are energy dissipators
which are used to reduce the velocity of
water flowing from a culvert or a paved
ford.
2. A hand-placed rock discharge apron is
often installed (see Figure 30). Individ-
ual rock pieces must be large enough to
remain in position under a heavy flow of
water (minimum diameter of 6 inches).
At least two layers of rock are placed to
provide sufficient depth to prevent un-
dercutting.
3. Heavier or continuous flows should dis-
charge onto a concrete or prefabricated
metal apron.
4. A concrete discharge apron from a
paved ford is shown in Figure 32, Paved
Ford.
5. Periodic inspections required for signs of
scour.
6. Refer to California Culvert Practice
(reference No. 32) for the design of con-
crete discharge aprons.
-------
142
ROCK APROt
CORRUGATED PIPE
FILLED WITH GRAVEL
-
;k^:> :/*
m^:^^' J&'*;&& -.-;.'''
*^S^^^i>;-^^^^*l'i'^rV-.:V/?*"-C'"'''--," - **£%$.
e*l£-«*K VS«f/ fSSSKF*-'^ "j3Ll '-'* .-' .'-'* -*.i-- ! -^'-'--:^
i" ^.-V-: -^-^:-'v^.'iv^ "..
/V/ry K Ami mo to, California Division of M'^ts and Geology
METAL APRON
Figure 30. Discharge Aprons.
-------
143
81.90 OPEN-TOP CULVERT [29]
Open-top culverts consist of boxlike frames
which are installed across the road flush with
the surface of the ground. Open-top culverts
may form temporary or permanent struc-
tures and are suitable for removing surface
water from lightly used, unpaved roads on
steep grades (Figure 31).
Except on highly-erodible soils or during
very wet weather, open-top culverts are not
usually required on grades of six percent or
less. Open-top culverts are generally ineffec-
tive on roads under continuous or seasonally
recurrent use where cleaning is sporadic.
81.91 DESIGN CONSIDERATIONS
1. Open-top culverts can be constructed
with lumber, logs, discarded highway
quadrails,
steel, etc.
or commercial corrugated
2. Open-top culverts are installed on a flow
-line gradient of 1/2 to 1 inch per foot
of length.
3. Channel is kept narrow to permit self-
cleaning with a minimum flow of water,
and to provide the least discomfort to
traffic.
4. Distances between open-top culverts
should be based on TabTe 21, Cross-
drain spacing for low to moderately
steep topography, and Table 22, Cross-
drain spacing for very steep topography.
5. If the required spacing is less than thirty
feet, the road should be paved with grav-
el or crushed rock. [46]
-------
144
END VIEW
NOTE: Materials other than lumber, such as logs, discarded highway
guardrails, or commercial corrugated steel may also be used.
Cut bonk
Toe of slope
Ditch (when required)
METHOD OF INSTALLATION
Figure 31. Open-Top Box Culvert. [29]
-------
Table 21. Grose-Drain Spacing* for Low to Moderate-
ly Steep Topography. [29]
145
ROAD GRADE
(Percent)
2-5
6-10
11-15
16-20
Spacing between
op en- top culverts
(feet)
300-500
200-300
100-200
100-
Note: Distances between culverts should be further .
decreased if the road surface material is highly
erodible.
Table 22. Cross-Drain Spacing* for Very Steep Topography. [46]
Forest soil groups in order of (1) decreasing coarseness and increasing
getachability of soil on road surfaces and (2) major parent materials
in each group
Group 1
Group 2 Group 3 Group 4
decreasing coarseness
and . of road surface soil
increasing detachability
Group 5
Group 6
hard sediments
shale (hard)
slate
argillite
rhyolite
rhyolite porphyry
limestone (hard)
basalt
basalt
porphyry
guartzite
conglomerate
gravel
granite
sandstone
gneiss
schist
sand
glacial silt
shale (soft)
andesite
andesite
porphyry
limestone
(soft)
loess
Crbss-drain spacinqs required to prevent rill or gully erosion
deeper than 1 inch on secondary 'logging roads
Road
grade 1
(percent)"
Soil group on which r6ad is located or built
Group 1
Group 2
; Group 3 ' :
Cross-drain spacing
Group 4
(feet)
Group 5
Group 6
167
154
137
135
105
95
4
6
8
152
144
137
139
131
124
'122
114
107
120
112
105
90
82
75
80
72
65
12
14
119
108
106
95
89
78
87
76
57
46
48
37
Table is based on location of road in the upper one-third of north-facing slopes having steepness
of 80 percent.
INSTRUCTIONS:
To determine cross-drain spacings for other positions on slope, different exposures, and sidehill
slope steepness less than 80 percent, apply the following instructions.
1. If road is located in the middle one-third of a slope, space 18 feet closer than shown;
If it is in the bottom third of a slope, space 36 feel; i-lnsaT-.
2. If road is located an an east or west exposure, space cross drains 8 feet closer than shown.
If road is on a south slope, space 16 feet closer.
3. For each 10 percent decrease" in steepness of the sidehill slope from a gradient of 80 percent
space cross drains 5 feet closer, than shown. »
-------
146
82.00 PAVED FORDS [29]
Paved fords are nonerodible road pavements
placed across a stream channel and permits
waterway crossing without causing erosion.
Fords are frequently used on roads subject to
flash floods, seasonal storm runoff peaks, or
frequent heavy passage of debris. This type of
crossing is less expensive than raising the
grade of the roao and installing a bridge or
culvert (Photo 42).
82.10 DESIGN CONSIDERATIONS
1. A type of paved ford with specifications
is shown in Figure 32.
2. The downstream side of paved fords re-
quires energy dissipators such as riprap
or concrete aprons.
Perry Y. Amimoto, California Division of Mines and Geology
Photo 42. A Paved Ford. (Tulare Co.)
-------
147
^.'. '.:..;...>?.;-: ;^£^?»
>'R. ^V^A^i^
:-?«8^«^i^;^;f^ife
' '-^mliiia^^^^
Cut away to show apron
Length of paved section (L)
depends on local requirements
Flow
PAVED ROADWAY
CONCRETE APRON
Stream Bed
Stone Paving
Low water drain pipe optional
Cut off to fit
local conditions
SECTION
drain
Into solid x ' V. 2" Drain
material thru cutoff
Rgure 32. Paved Ford. [29]
-------
148
83.00 BRIDGES
Bridges provide protection against erosion
and sediment deposition along waterways by
maintaining full, unobstructed flow in the
channel and by keeping road grade above
stream level (Photo 44).
83.10 DESIGN CONSIDERATIONS
The design of bridges requires information
on the foundation, hydrology, and sediment
debris hazard.
?'-' -
.- . .
Jf
'
-
California Department of Forestry
Photo 43. A Pipe-Arch Bridge.
-------
149
Section 90
SEDIMENT TRAPS
AND DETENTION BASINS
-------
151
91.00 SEDIMENT TRAPS
Sediment traps are vegetative or structural
measures which trap sediment at on-site
construction areas to prevent clogging of
drainage control structures and reduce sedi-
ment runoff. Types of sediment traps include
filter berms, sandbag or straw-bale barriers,
filter inlet, vegetative filter strip, culvert ris-
er. Photo 44 shows the need for sediment
traps.
91.10 FILTER BERM [57]
1. General
a.
b.
The filter berm is a temporary sedi-
ment trap and consists of a ridge of
gravel or crushed rock constructed
across a graded right-of-way. See
Figure 33.
Filter berms retain sediment on-site
by retarding and filtering runoff
while at the same time allowing con-
struction traffic to proceed along the
right-of-way.
c. Filter berms are also applicable for
use in drainage ditches prior to road-
way paving and establishment of
permanent ground cover. '
d. After each storm remove trapped
sediment and clean out or replace
clogged filter material.
\
2. Specifications
a. Height: 1.5 to 2.0 feet (uniform top
elevation)
b. Top Width: 3 to 5 feet.
c. Side Slopes: 3:1 or flatter.
d. Spacing: 200 to 300 feet (steeper
-lopes require closer spacing.)
e. Material: Coarse (3/4" to 3"), well
graded gravel or crushed rock. Fines
less than 5 percent.
91.20 SANDBAG OR STRAW BALE BARRI-
ERS [57]
1. General
a. Sandbag or straw bale barriers are
temporary sediment traps which re-
tain sediment on-site by retarding
and filtering storm runoff and are
used at storm drain inlets, drainage-
ways, and across rights-of-way. See
Figure 34.
b. Dikes of sandbags or straw bales
constructed across a right-of-way
or immediately below the site of con-
struction activities should have a
low spillway-embankment section
of sand and gravel filter that serves
as a filter outlet.
c. The barriers must be installed so
that runoff cannot escape freely un-
der the straw bales or sandbags.
2. Specifications
a. Straw bales bound with nylon or
wire are more durable than twine-
bound bales.
b. Straw bales should be anchored to
the ground with steel rods, fence
posts, rebars, wood pickets, etc. Two
anchors per bale are required.
Graded R.O.,VV.
s - 3:1 or Flatter
Figure 33. Filter Berm. [57]
-------
152
c. Sandbags exceeding two bags in
height may require anchoring with
steel rods, rebars, etc.
91.30 FILTER INLET [57]
1. General
a. A filter inlet is a temporary sediment
trap consisting of gravel or crushed
rock placed at storm sewer curb in-
let structures. See Figure 35.
b. Filter inlets retain sediment on-site
by retarding and filtering storm run-
off before it enters the storm or sew-
er system.
c. Trapped sediment should be
removed and the clogged filter
material cleaned out or replaced af-
ter each storm.
2. Specifications
;
a. Concrete building blocks placed in
throat of inlet. Filter material placed
between blocks and street in the gut-
ter section. See Figure 35.
b. All filter material should be coarse
(3/4" to 3"), well graded gravel or
crushed rock. Fines less than five
percent.
91.40 VEGETATIVE FILTER STRIP
1. General
a. A vegetative filler strip is a tempo-
rary or permanent sediment trap
which consists of an area of vegeta-
tive cover through which storm wa-
ter must flow before it enters
streams, storm sewers, conduits, etc.
b. As the water containing suspended
solids flows through the vegetative
filter strip, some of the sediment is
removed by "filtering" and by depo-
sition as the flow velocity is reduced.
c. Vegetative filter strips are naturally
occurring or man-made.
d. Tall, dense stands of grasses form
the best sediment traps.
2. Specifications
a. Naturally occurring vegetation may
suffice. Light fertilizing may en-
hance the growth.
b. Man-made grasses may be provided
by sod or by planting.
c. Minimum width of vegetative filter
strips:
Above Diversions: 15' plus 1/2 of
channel width. [21]
Along Live Streams: 100' minimum
(Recommended by California De-
partment of Fish and Game in log-
ging areas.)
91.50 CULVERT RISER
1. The culvert riser is described in the
chapter on culverts.
2. The chapter on sediment detention ba-
sins should help in the safe storage de-
sign of culvert risers.
92.00 SEDIMENT DETENTION BASIN
A sediment detention basin is a reservoir
which retains high flows sufficiently to cause
deposition of transported sediment. Sedi-
ment basins may be either temporary or per-
manent structures which prevent off-site
transportation of sediment generated from
construction activities. See Photos 45,46 and
Figure 36.
92.10 DESIGN CONSIDERATIONS
1. The design of the sediment basin shall be
based on the total drainage area lying
upstream and on the future use of such
lands.
2. The spillway overflow from a debris ba-
sin should not increase the down stream
sediment loads.
3. Vegetation should be planted on slopes
of embankments composed of erodible
soil.
-------
153
4. Beyond certain limitations on the height
of the dam and the storage capacity of
the reservoir, the design of the sediment
basin will come under the jurisdiction of
the California Division of Safety of
Dams (See Table 23).
5. For basins which also serve as perma-
nent water storage consideration should
be given to the prevention of "algae
bloom" which is aesthetically unsightly.
92.11 STORAGE [57]
1. The site should be selected to provide
adequate storage.
2. Storage capacity shall be the volume be-
low the pipe spillway crest or emergency
spillway crest.
3. Consideration should be given to plan
for periodic cleanout in order to main-
tain the capacity requirements.
4. The maximum allowable level of depos-
ited sediment before cleanout shall be
determined and given in the design data
as a distance below the top of the riser.
92.12 PIPE SPILLWAY [20] [57]
1. The combined capacity of the pipe and
emergency spillways will be designed to
handle the design flood.
2. Runoff will be figured by an acceptable
^ \hydrologic procedure, and should be
based on drainage area conditions ex-
pected to prevaiWuring the anticipated
1 effective life of the structure.
/ \
/ i
3. The pipe spillway will consist of a per-
forated vertical pipe or box-type riser
joined to a horizontal pipe conduit
(barrel) which will extend beyond the
downstream toe of the embankment.
4. The horizontal pipe conduit (barrel)
will be a minimum of 12 inches in di-
ameter.
5. The riser is a minimum of 30 inches in
diameter and has a cross-sectional area
of at least 1.5 times the cross-sectional
area of the horizontal pipe conduit.
6. The crest elevation of the riser shall be
such that full flow will be generated
before there is discharge through emer-
gency spillway and at least one foot be-
low crest of emergency spillway.
7. If no emergency spillway is provided,
the crest elevation of riser must be at
least three feet below crest of emer-
gency spillway.
8. The upper 1/2 to 2/3 of the riser shall
be perforated with 1-1/2 to 4 inch
holes, 10 to 12 inches on center and
staggered.
9. The antivortex device can increase vol-
ume of discharge by as much as 50 per-
cent.
10. An approved antivortex device is a
thin, vertical plate normal to the cen-
terline of the dam and firmly attached
to the top of the riser. The plate dimen-
sions are:
Height = diameter of barrel
Length = diameter of riser plus 12
inches
11. The riser shall have a base attached
with a watertight connection and shall
have sufficient weight to prevent flota-
tion of the riser. Three recommended
methods are:
a. A square concrete base 18 inches
thick with the riser embedded six
inches in the base. Each side of base
will be diameter of standpipe plus
24 inches.
b. A 1/4 inch minimum thickness
steel plate welded all around the
base of the riser to form a water-
tight connection. The plate shall be
square with each side equal to two
times the riser diameter. The plate
shall have two feet of stone, gravel,
or tamped earth placed on it to pre-
vent flotation.
c. Properly anchored guy wires may
be substituted for the anchor block.
-------
154
12. The trash rack consisting of #4 bars, 6
inches on center shall be welded across
the top of riser.
13. At least one seepage ring is required
and each ring shall be rectangular with
each side a minimum of barrel diameter
plus 24 inches.
92.13 EMERGENCY SPILLWAY [20] [57]
1. The emergency spillway should be de-
signed for 1.5 maximum design flow.
Two recommended designs are:
a. Discharge over top of dam or em-
bankment. Spillway must be lined
with 3 inch thick gunite or 4 inch
concrete reinforced with 6x6-
10/10 wire mesh, extending to a
minimum of 3 feet down the up-
stream face of embankment. Spill-
way will be minimum of 18 inches
deep with 1 1/2:1 side slopes.
b. Earth spillways must be installed on
undisturbed soil (not on fill) by
grading. Side slopes will not be
steeper than 2:1. Embankment and
spillway channel must be protected
by vegetation, rock riprap, etc. The
maximum allowable velocity in exit
channel shall be 6 feet per second.
92.14 FREEBOARD [49]
1. Freeboard is the vertical distance
between the elevation of the water sur-
face in the pond when spillway is dis-
charging at designed depth and the
elevation of the top of the dam after all
settlement has taken place.
2. Minimum freeboard shall be 1.0 foot for
sediment basins where the maximum
length of pond is less than 660 feet.
92.15 EMBANKMENT [49]
1. The embankment shall have top widths
based on the following:
Height Top
of dams width
under 10' 8'
10'-15' 10'
15-20' 12'
20-25' 14'
2. Side slopes shall be no steeper than 2:1.
92.20 CONSTRUCTION [23] [20]
92.21 SITE PREPARATION
1. The foundation area reservoir area shall
be cleared of all trees, stumps, roots,
brush, boulders, sod, and debris.
2. All topsoil containing excessive amounts
of organic matter shall be removed.
92.22 BORROW AREAS
1. All borrow areas outside the pool shall
be graded, seeded, and left in such a
manner that they are well drained and
protected from erosion.
92.23 EMBANKMENT
1. The embankment material shall be taken
from borrow areas as stated on plans.
2. The material shall be free of all sod,
roots, woody vegetation, large rock (ex-
ceeding 6 inches in diameter,) and other
debris.
3. The embankment should be constructed
to an elevation which provides for an-
ticipated settlement to design elevation
(allow 10% for settlement).
4. The foundations for embankment shall
be scarified prior to placement of fill.
5. Placement of fill material shall be started
at the lowest point of the foundation and
shall be placed in 6 inch maximum lifts
which are to be continuous over entire
length of fill and approximately horizon-
tal.
6. The satisfactory compaction is usually
achieved when the entire surface of the
fill is traversed by at least one pass of the
loaded hauling equipment or through
use of a roller.
92.24 PIPE SPILLWAY
1. The barrel shall be placed on a firm
foundation to the lines and grades shown
on the plans.
-------
155
2. Backfill material shall be placed around
the barrel in 4 inch layers and each layer
shall be thoroughly compacted with suit-
able hand-operated equipment to at
least 2 feet above the top of the pipe and
seepage rings before heavy equipment is
operated over it.
92.25 VEGETATIVE PROTECTION
1. A protective vegetative cover shall be es-
tablished on all exposed surfaces of the
embankment, spillway, and borrow area
to the extent practical.
92.26 PROTECTION OF SPILLWAY DIS-
CHARGE AREA
1. All areas subject to discharges from pipe
spillway and emergency spillway must
be protected with vegetation, rock, rip-
rap, etc.
92.30 SEDIMENT CLEANOUT AND DIS-
POSAL
1. The sediment should be removed when-
ever the storage capacity has been re-
duced to unsafe, improperly functioning
levels.
2. The sediment must be disposed of in
such a manner that will prevent its re-
turn to the sediment basin or movement
into downstream areas during subse-
quent runoff.
USDA Soil Conservation Service
Photo 44. A Sediment Trap Would Have Allowed This Storm Sewer System to Collect Runoff Without Excessive Sediment Load.
-------
156
~7rrn
* ~-!»^Storm sewer structure
Gutter
Anchor with two stakes
driven into the ground
Temporary barrier of hay bales to prevent sediment-laden water from entering
incomplete storm sewer system.
Flow
Top View
Bales of straw staked down
Provide sand and gravel filter outlet
at lower area along with" straw bales
Front view
Semi -pervious barrier of hay bales with more pervious embankment of sand and
gravel for spillway.
Figure 34. Temporary Barrier of Straw Bales to Prevent Sediment-Laden Water from Entering Incomplete Storm Sewer. [57]
-------
157
Plywood top
Building block laid in throat-
web horizontal
Sand & gravel filter
Figure 35. Sand and Gravel Filter Protecting Intake Area of Incomplete Storm Sewer System. [56]
-------
158
USDA Soil Conservation Service
Photo 45. Sediment Detention Basin.
-------
159
Table 23. Design Limitations and Jurisdiction of Dams in California. [39]
Cond-
ition
1
2
3
4
5
DESIGN
HEIGHT
(ft)
<6
No limit
<15
>25
No limit
STORAGE
(acre~ft)
No limit
<15
No limit
>15
>50
USE OP DAM
Impound or divert
water.
Impound or divert
water.
Underground per-
colation.
Impound or divert
water.
Impound or divert
water.
Jurisdiction by the
California Division
of Safety of Dams
No (sec. 6003)
No (sec. 6003)
No (sec. 6004)
Yes (sec. 6002a)
Yes (sec. 6002b)
-------
160
ANTI-VORTEX PLATE
RISER
ENERGY DISSIPATOR
NATURAL1 GROUND
ANTI-SEEP COLLAR
GRAVEL CONE
MINIMUM DESILTING BASIN STANDARD
/" / s~ '
, ' ' -C '
RIPRAP "
6" MIN. f
SIZE [
! . ". /' j
|__- _.
j
2"
l\ "
f
F
|SS* X
1
pl~^~
l=-A .
V
^
^
-
-,
7(12" DIA.MIH.)
/
/ i
C___i 1 OFFSET
h -_©"
(WHITE OR >t"CONCRETE
6x6-10/10 HIRE MESH
SBCTIOH A-A
OUNITE OR CONCRETE AT THE
OVERFLOW IS TO EXTEND 3' MIH.
DOWN EACH FACE OF THE DIKE.
-S'MIN.
DISCHARGE TO PAVED
STREET OR APPROVED
DRAINAGE COURSE
ix PAVED CHANN:
NOTE!
SEEPAGE
RING 3-
BASE IN
COMPETENT MATERIAL
COMPACTION REPORTS ARE TO BE SUBMITTED
ON EACH DIKE PRIOR TO FINAL APPROVAL
<ft BARS g 6" C.C.WELDED
2. ACROSS TOP OF STAHDPIPE
, 30" DIAMETER STANDnPE
«« PERFORATIONS 12" 0/C STAGGERED
I) PROPERLY ANCHORED GUY WIRES
MAY BE SUBSTITUTED FOR THE
ANCHOR BLOCK.
21 SEE SECTION 92.15 FOR
RECOMMENED WIDTH OF
EMBANKMENT.
Figure 36. Schematic Design of Sediment Detention Basins. [20] [56]
-------
161
Perry Y. Amimoto California Division of Mines and Geology
Photo 46. Sediment Detention Basin Used to Protect the Culvert and Roadway. (Tulare Co.)
-------
163
Section 100.
DISSIPATING THE ENERGY
OF RUNOFF WATER
-------
165
100.00 ENERGY DISSIPATORS
Energy dissipators are used at all outlets
discharging on credible soil. The energy dis-
sipator may be used temporarily during
construction or may be a permanent feature
of drainage control measures. Common
types of energy dissipators are level spread-
er, discharge apron, drop inlet, hydraulic
jump.
101.00 LEVEL SPREADER [41]
Level spreaders are energy dissipators
which are used at diversion outlets to con-
vert channel flow into sheet flow. See Fig-
ure 37.
Level spreaders must be constructed in un-
disturbed soil and outlet onto an area stabil-
ized with vegetation. Design considerations
are shown hi Figure 37.
102.00 HYDRAULIC JUMP
The hydraulic jump is a permanent, con-
crete structure used to dissipate the energy
of concentrated runoff flowing down very
steep slopes. (Photo 47).
An advantage is that this structure occupies
a smaller area than other methods.
A disadvantage is that unless continually
maintained, sediment deposits in the struc-
ture will decrease the effectiveness of the
hydraulic jump.
Formal design is required. Reference
should be made to standard engineering
handbooks.
103.00 DISCHARGE APRONS
Discharge aprons are covered in Section
81.80 as part of the discussion on culvert
appurtenances.
104.00 DROP INLET
Drop inlets are covered in Section 81.70 as
a culvert appurtenance.
-------
166
Undisturbed Slope
Undisturbed soil stabilized by
existing vegetation. Repair areas
damaged during construction with sod.
3:1 or
Flatter
mm-
SECTION A-A
Channel Grade 0.0%
grade O.&to l.(
6' min
compacted diversion
fld9e PLAN VIEW
Level 1ip above
undisturbed, stabilized
area
Undisturbed Soil
Stabilized by
Existing Vegetation
FLOW (Q)vs SPREADER LENGTH (L)
Figure 37. Level Spreader. [22] [57]
Q
(cfs)
Up to 10
1 0 - 20
2IX- 30
31 - 40
41 - 50
L
(ft)
15
20
26
36
44
-------
167
California Division of Resource Conservation
Ay - . "^ *3 ^H^^^» Jk.-*
M^m^L
Photo 47. A Hydraulic Jump Typ« Energy Dissipator Device Used to Prevent Erosion Along a Road
Drainage.
-------
168
GLOSSARY
A glossary of terminology relating to erosion and
sediment control practices and ordinances is includ-
ed here to help the unfamiliar. Also, in the chapter
on vegetative measures, a cross-index relates the
common names versus the scientific names of
grasses, legumes, and shrubs.
ACID SOIL - A soil with a preponderance of hydro-
gen ions, and probably of aluminum proportion to
hydroxyl ions. Specifically, soil with a pH value
less than 7.0. For most practical purposes, soil
with a pH value less than 6.6. The pH values
obtained vary greatly with the method used;
consequently, there is no unanimous agreement on
what constitutes an acid soil. The term is usually
applied to the surface layer or to the root zone
unless specified otherwise.
ACRE-FEET - An engineering term used to denote
a volume one acre in area and one foot in depth.
ALKALI SOIL - (1) A soil with a high degree of
alkalinity (pH of 8.5 or higher) or with a high
exchangeable sodium content (15 percent or more
of the exchange capacity) or both. (2) A soil that
contains sufficient alkali (sodium) to interfere
with the growth of most crop plants.
ANGLE OF REPOSE - Angle between the horizon-
tal and the maximum slope that a soil or other
material assumes through natural processes.
ANNUAL PLANT (ANNUALS) - A plant that
completes its life cycle and dies in one y«ar or less. :
APPLICANT - A person, partnership, corporation
or public agency requesting permission to engage
in land disturbance activity.
APRON - A floor or lining to protect a surface from
erosion, for example, the pavement below chutes,
spillways, culverts, or at the toes of dams.
ASPECT - The direction that a slope faces.
BEDLOAD - The sediment that moves by sliding,
rolling, or bounding on or very near the
streambed; sediment moved mainly by tractive
forces and at velocities less than the surrounding
flow.
BEDROCK - The more or less consolidated
inplace either on or beneath the surface of tjie
earth.
BENCH - A relatively level step excavate
earth material on which fill is to be pi
BORROW - Earth material acquired from an off-
site location for use in grading on a site.
BROADCAST SEEDING - Scattering seed on the
surface of the soil. Contrast with drill seeding
which places the seed in rows in the soil.
CHANNEL - A natural stream that conveys water;
a ditch or channel excavated for the flow of water.
CHANNEL STABILIZATION - Erosion preven-
tion and stabilization of velocity distribution in
channel using drops, revetments, vegetation, and
other measures.
CHECK DAM - Small dam constructed in a gully
or other small watercourse to stabilize the grade
and control head cutting.
CHUTE - A high-velocity, open channel for con-
veying water to a lower level without erosion.
CLAY - (1) Mineral soil grains less than 0.002 mil-
limeter in equivalent diameter. (2) A soil textural
class. (3) (Engineering) A fine-grained soil that
has a high plasticity index in relation to the liquid
limits.
CLEARING - The removal of vegetation, struc-
tures or other objects.
COMPACTION - The densification of a fill by me-
chanical means.
CRITICAL AREA - A severely credible area.
CUT - An excavation. The difference between a
point on the original ground and a designated
point of lower elevation on the final grade. Also,
the material removed in excavation.
DAM - A barrier to confine or raise water for stor-
age or diversion, to create a hydraulic head, to
prevent gully erosion, or for retention of soil, rock,
or other debris.
DEBRIS - A terni applied to the loose material
arising from the disintegration of rocks and vege-
tative material; transportable by streams, ice, or
floods.
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169
DIKE - A berm of earth or other material construct-
ed to confine or control surface water in an estab-
lished drainage system
DIVERSION - A diversion is a temporary or per-
manent structure consisting of a channel or ditch
and a ridge constructed across a sloping land sur-
face on the contour or with predetermined grades
to intercept and divert surface runoff before it gains
sufficient volume and velocity to cause erosion.
DRAINAGE - The removal of excess surface water
or groundwater from land by means of surface or
subsurface drains.
DRAINAGE WAY - Natural depression in the
earth's surface such as swales, ravines, draws, and
hollows in which surface waters collect as a result
of rain or melting snow but at other times are
destitute of water.
DRAINAGE PATTERN - The configuration or
arrangement of streams within a drainage basin or
other area.
DRIP LINE - An imaginary line of the ground sur-
face that corresponds to the farthest lateral exten-
sion of the branches of a tree.
DRILL SEEDING - Planting seed with a drill in
relatively narrow rows, generally less than a foot
apart. Contrast with broadcast seeding.
DROP-INLET SPILLWAY - Overfall structure in
which the water drops through a vertical riser
connected to a discharge conduit.
DROP STRUCTURE - A structure, for dropping
water to a lower level and dissipating its surplus
energy; a fall. A drop may be vertical or inclined.
EARTH MATERIAL - Any rock, natural soil or
fill and/or any combination thereof.
EASEMENT (CONSTRUCTION, DRAINAGE,
PLANTING, SLOPE) - A right to use or control
the property of another for designated purposes.
CONSTRUCTION EASEMENT - An easement
to permit the full development of the construc-
tion prism.
DRAINAGE EASEMENT - An easement for
directing the flow of water.
PLANTING EASEMENT - An easement for re-
shaping roadside areas and establishing, main-
taining, and controlling plant growth thereon.
SLOPE EASEMENT - An easement for cuts or
fills.
ENERGY DISSIPATOR - A device used to reduce
the excess energy of flowing water.
ERODIBLE - Susceptible to erosion.
EROSION - The wearing away of the land surface
by running water, wind, ice, or other geological
agents, including such processes as gravitational
creep.
EROSION AND SEDIMENT CONTROL PLAN
- A plan which fully indicates necessary land
treatment and structural measures, including a
schedule of the timing for their installation, which
will effectively minimize soil erosion and sediment
yield. Such measures may be in accordance with
standards shown in this Erosion and Sediment
Control Handbook.
EXCAVATION - Any activity by which earth,
sand, gravel, rock, or any other similar material is
dug into, cut, quarried, uncovered, removed, dis-
placed, relocated or bulldozed and shall include
the conditions resulting therefrom.
EXISTING GRADE - The grade prior to grading.
FILL - A deposit of earth material placed by artifi-
cial means; any act by which earth, sand, gravel,
rock, or any other material is placed, pushed,
dumped, pulled, transported, or moved to a new
location above the natural surface of the ground
or on top of the stripped surface and shall include
the conditions resulting therefrom. The difference
in elevation between a point on the original
ground and a designated point of higher elevation
on the final grade.
FILTER BLANKET - A layer of sand and /or
gravel designed to prevent the movement of fine-
grained soils.
FILTER STRIP - Strip of vegetation that retards
flow of runoff of water, causing deposition of
transported material, thereby reducing sediment
flow.
FINISH GRADE - The final grade of the site which
conforms to the approved plan.
FLOOD PLAIN - The relatively flat area adjoining
the channel of a natural stream which has been or
may be hereafter covered by flood water. (
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170
FLUME - A device constructed to convey runoff of
water on steep grades.
GERMINATION - Sprouting; beginning of growth.
GRADE - The vertical location of the ground sur-
face.
GRADE CONTROL STRUCTURE - A structure
for the purpose of stabilizing the grade of a water-
course, thereby preventing further headcutting or
lowering of the channel grade.
GRADIENT - Change of elevation, velocity, pres-
sure, or other characteristics per unit length of
slope.
GRADING - Any stripping, cutting, filling, stock-
piling, or any combination thereof and shall in-
clude the land in its cut or fill condition.
GROUNDWATER - Phreatic water or subsurface
water in the zone of saturation.
GULLY - A channel or miniature valley cut by
concentrated runoff but through which water
commonly flows only during and immediately af-
ter heavy rains or during the melting of snow* The
distinction between gully and rill is one of depth.
A gully is sufficiently deep that it would not be
obliterated by normal tillage operations, whereas
a rill is of lessor depth and would be smoothed by
ordinary farm tillage.
HEAVING - The partial lifting of plants out of the
ground, frequently breaking their roots, as a result
of freezing and thawing of the surface soil during
the winter. x
HERBICIDES - Chemicals used to control or eradi-
cate vegetation.
HYDRAULIC GRADIENT - The slope of the hy-
draulic grade line. The slope of the free surface of
water flowing in an open channel.
HYDRAULIC JUMP - Sudden rise in water level
from a flow stage below critical depth to flow stage
above critical depth, during which the velocity
passes from supercritical to subcritical.
INNOCULANT - A peat carrier impregnated with
bacteria which form a symbiotic relationship ena-
bling legumes to utilize atmospheric nitrogen.
Most of our legumes require specific bacteria.
INTERCEPTOR DITCH - Interceptor ditches are
permanent structures located on top of a cut slope
that divert drainage away from the slope of the
cut.
KEY - A designed compacted fill placed in a trench
excavated in earth material beneath the toe of a
proposed fill slope.
LAND DISTURBANCE - Any activity involving
the clearing, grading, filling, and any other activ-
ity which causes land to be exposed to the danger
of erosion.
LEGUME - A member of the legume or pulse fam-
ily, Leguminosae. The fruit is a "legume" or pod
that opens along two sutures when ripe. Flowers
are usually papilionaceous (butterflylike). Leaves
are alternate, have stipules, and are usually com-
pound. Includes many valuable food and forage
species, such as the peas, beans, peanuts, clovers,
alfalfas, sweet clovers, lespedezas, vetches, and
kudzu. Practically all legumes are nitrogen-fixing
plants.
LEVEL SPREADERS - A shallow excavation at
the outlet end of a diversion with a level section
for the purpose of diffusing the diversion outflow.
LINING - A protective covering over all or part of
the perimeter of a reservoir or a conduit to prevent
seepage losses, withstand pressure, resist erosion,
and reduce friction or otherwise improve condi-
tions of flow.
MULCH - A natural or artificial layer of material
placed on exposed earth to provide more desirable
moisture and temperature relationships for plant
growth. It is also used to control the occurrence
of unwanted vegetation.
OUTLET - Point of water disposal from a stream,
river, lake, tidewater, or artificial drain.
PERENNIAL PLANT - A plant that normally
lives for three or more years.
PERMEABILITY - Capacity for transmitting a
fluid. It is measured by the rate at which a fluid
of standard viscosity can move through material
in a given interval of time under a given hydraulic
gradient.
PERMEABLE - Having a texture that permits wa-
ter to move through it.
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171
PERMIT - A certificate issued to perform work.
PERMIT - ISSUING AUTHORITY - The local
government within the territory of which the
proposed construction and maintenance of land
fills, excavations, cuts, clearing of vegetation or
revegetation is located, which government has the
authority and obligation to enforce the standards
established by this Ordinance.
pH - A numerical measure of the acidity or hydro-
gen ion activity of a soil. The neutral point is pH
7.0. All pH values below 7.0 are acid and all above
7.0 are alkaline.
REVETMENT - Facing of stone or other material,
either permanent or temporary, placed along the
perimeter of a stream to stabilize the bank and to
protect it from the erosive action of the stream.
RILL EROSION - An erosion process in which
numerous small channels only several inches deep
are formed; occurs mainly on recently cultivated
soils.
RUNOFF - The surface water flow or rate of flow
over a given watershed after a fall of rain or snow
melt.
SALINE SOIL - A soil containing sufficient soluble
salts to impair its productivity but not containing
excessive exchangeable sodium. This name was
formerly applied to any soil containing sufficient
soluble salts greater than 3,000 parts per million.
SAND - (1) A soil particle between 0.05 and 2.0
millimeters in diameter. (2) Any one of five soil
separates: very coarse sand, coarse sand, medium
sand, fine sand, and very fine sand. (3) A soil
textural class.
!
SCARIFY - To abrade, scratch, or modify the sur-
face, for example, to break the surface of the soil
with a narrow-bladed implement.
SCOUR - To abrade and wear away. Used to de-
scribe the wearing away of terrace or diversion
channels or streambeds.
s
SEDIMENT - Solid material, both mineral and or-
ganic, that is in suspension, is being transported,
or has been moved from its side of origin by air,
water, gravity, or ice and has come to rest on the
earth's surface either above or below sea level.
SEDIMENT DETENTION BASIN - A sediment
detention basin is a reservoir which retains flows
sufficiently to cause deposition of transported
sediment.
SEDIMENT LOAD - The quantity of sediment,
measured in dry weight, or by volume, trans-
ported through a stream cross section in a given
time. Sediment load consists of both suspended
load and bedload.
SEDIMENT POOL - The reservoir space allotted to
the accumulation of submerged sediment during
the life of the structure.
SEDIMENTATION- The process ,by which
mineral or organic matter is removed from its
site of origin, transported, and deposited by
water, wind, or gravity.
SEED PURITY - The percentage of the desired
species in relation to the total quantity, including
other species, weed seed, and foreign matter.
SEEPAGE - (1) Water escaping through or emerg-
ing from the ground along an extensive line or
surface as contrasted with a spring where the wa-'i
ter emerges from a localized spot. (2) The process i
by which water percolates through the soil.
SHEET EROSION - The removal of a fairly uni-
form layer of soil from the surface by runoff water.
SHEET FLOW - Water, usually storm runoff, flow-
ing in a thin layer over the'ground surface1. Syno-
nym: overland flow.
SIDE SLOPES - The slope of the sides of a canal,
dam, or embankment. It is customary to name the
horizontal distance first, as 1.5 or 1, or frequently
1-1/2:1, meaning a horizontal distance of 1.5 feet
to 1 foot vertical. ' i
SILT - (1) A soil separate consisting of particles
between 0.05 and 0.002 millimeter in equivalent
diameter. (2) A soil textural class.
SITE - Any lot or parcel of land or contiguous com-
bination thereof, under the same ownership,
where grading is performed or permitted.
SLASH - The branches, bark, tops, cull logs, and
broken or uprooted trees on the ground after log-
ging.
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172
SLIP - The downslope movement of a soil mass
under wet or saturated conditions; a microland-
slide that produces a microrelief in soils.
SLOPE - An inclined ground surface, the inclination
of which is expressed as a ratio of horizontal dis-
tance to vertical distance. The face of an embank-
ment or cut section.
SLOPE DRAINS - Permanent or temporary devices
that are used to carry water down cut or embank-
ment slopes. May be pipe, half sections, paved or
special plastic lining.
SOD - A closely-knit ground cover growth primar-
ily of grasses.
SOIL - The unconsolidated mineral and organic
material on the immediate surface of the earth.
STILLING BASIN - An open structure or excava-
tion at the foot of an overfall, chute, drop, or
spillway to reduce the energy of the descending
stream.
STRIPPING - Any activity which significantly dis-
turbs vegetated or otherwise stabilized soil surface
including clearing and grubbing operations.
SWALE - A low lying stretch of land which gathers
or carries surface water runoff.
TOP SOIL - Surface soils and subsurface soils which
presumably are fertile soils and soil material, ordi-
narily rich in organic matter or humus debris.
Topsoil is usually found in the uppermost soil
layer called the A horizon.
TERRACE - A relatively level step constructed in
the face of a graded slope surface for drainage and
maintenance purposes.
WATER TABLE - The upper surface of groundwa-
ter or that level below which the soil is saturated
with water; locus of points in soil water at which
the hydraulic pressure is equal to atmosphere
pressure.
WATERCOURSE - A permanent stream; intermit-
tent stream; river; brook; creek; channel or ditch
for water, whether natural or man-made.
WATERSHED - All the land and water within the
confines of a drainage divide.
WATERWAY - A natural course or constructed
channel for the flow of water.
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173
BIBLIOGRAPHY
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'^
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174
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\
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PHYSICAL AND CLIMATIC FACTORS
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179
APPENDIX I: ESTIMATING EROSION AND SEDIMENT LOSSES
A. Summary of Methods in Appendix I for Com-
puting the Rate of Erosion and Sediment Yield.
B. Sheet Erosion Computation
1. Sediment Predictive Yield
2. Pacific Southwest Interagency Committee
Method (PSIAC)
C. Roadway Erosion Computation
1. Road Density vs. Sediment Production
2. Surface Area of Cut and Fill
D. Downstream Sediment Delivery Computation
1. Meyer-Peter and Muller Method
Summary of Methods in Appendix I for Com-
puting the Rate of Erosion and Sediment Yield.
Table 24, "Summary of methods in Appendix I
for computing erosion and sediment yield",
shows the alternative methods and the factors
used in estimating erosion.
On-site erosion is considered separately from
downstream sediment delivery, because the
amount of sediment transported does not occur
simultaneously with erosion. In some areas,
considerable erosion may take place before the
eroded material is transported downstream.
An estimate of potential on-site erosion for a
development is the sum of the sheet erosion and
roadway erosion methods.
B. Sheet Erosion Computation
1. Sediment Predictive
Method [8]
Yield - Flaxman
a. This method computes sediment yield
on an average annual rate in acre-ft per
square mile per year.
b. The formula is derived from the analysis
of numerous watersheds in the western
United States (See Figure 38). A con-
venient nomograph is included for com-
putation.
c. The following field data is required:
Slope (X2):
Use weighted average, such as (con-
tour intervals)/average width
between contours.
Aggregation Index (X<):
Percent of soil 2 microns or finer in
size of 2-inch depth soil sample. Use
2.
(+) if pH is alkaline and (-) if pH
is acid or neutral (7.0).
Soil Particle Size (X3):
Percent of soil particles coarser than
one millimeter in the surface 2 inches
of the soil.
Precipitation/Temperature Ratio (Xi):
Average annual precipitation
(inches) divided by average annual
temperature (degrees F). Use ratio of
0.0 where vegetation is stripped for
development. In areas of considerable
snowpack, the precipitation/temper-
ature ratio may be increased as de-
scribed in reference No. 8 due to the
effect of snow in reducing the rate of
erosion.
Sediment Yield (Y):
Volume sediment in acre-feet per
square mile per year.
Pacific Southwest Interagency Committee
Method (PSIAC) [24]
a. This method shown on Table 25 com-
putes erosion on a qualitative basis and
is very useful for making preliminary
estimates or checking other methods.
b. The analysis involves a consideration of
twelve factors including soils, hydrolo-
gy, topography, etc.
c. The erosion is computed numerically in
acre-feet per year per square mile. A
sample computation is shown on the
bottom of Table 25.
C. Roadway Erosion Computation
1. Road Density vs. Sediment Production
-------
180
a. This method shown in Figure 39 com-
putes roadway erosion on the basis of
road density (the number of miles of
road per square mile).
b. The chart is based on data from the
north coastal lake Tahoe, and San
Francir-o Bay areas of California.
c. This method is to oe used only in areas
of steep topography, moderately erodi-
ble soil, and moderate rainfall, and is
used when aesincg a rough estimate.
2. Surface Area of Cut aac Fill
a. This method of computing erosion
shown in Figures 40, 41, and 42 com-
bines roadway and ground slope dimen-
sions with a judgement of depth of
erosion.
b. By considering tie width of roadway,
maximum height of cut and fill, and the
ground slope the surface area of cut and
fill is determined from the chart in acres
per mile of road.
c. An assumption is made as to the average
depth of erosion along the surface area
of cut and fill and this depth times the
surface area gives a value of roadway
erosion in acre-feet per mile of road.
d. This method is not only useful for es-
timating the volume of on-site erosion
during the construction activity but also
is useful for estimating the area needing
revegetation.
D. Downstream Sediment Delivery
1. Meyer-Peter and Muller Method
a. This method computes the downstream
sediment delivery as the bedload frac-
tion of sediment transport (Figure 43)
and does not include suspended load.
b. The comt utation -f b?dload would help
to solve problems such as the design
capacity of sediment detention basins
and the amouru of sediment deposition
along stream channels.
c. A chart for the graphical computation
of the Meyer-Peter and Muller method
is included, and it should be used as an
approximation of the method because of
several assumptions.
d. To use the chart:
1. Determine (d), the depth of flow
in feet.
2. Determine (S), slope of hydraulic
gradient.
2. Use (d) and (S) to find (&), the
sediment transport in tons per day
per foot of channel width.
4. Multiply bottom width of channel
in feet to obtain bedload dis-
charge.
e. The explanation of the terms in the
equation are: '
gs = bedload discharge in tons per day
per foot of channel width.
Q = total water discharge in cubic feet
per second.
Qs = water discharged transporting a
specific bedload, in cubic feet per
second. ,,
= particle size at which 90% of
the bed material is finer in milli-
meters.
ns = Manning "n" value for the
streambed.
d = depth of flow in feet.
S = slope of hydraulic gradient in
feet per foot.
Dm = effective size of bed material in
millimeters.
-------
Table 24. Summary of Methods in Appendix I for Computing Erosion and Sediment Yield.
GROUND SLOPE ,
ANNUAL PRECIPITATION
ANNUAL TEMPERATURE
SOIL TYPE
ROAD DENSITY
SLOPE CUT AND PILL
ROAD WIDTH & GRADIENT
HYDRAULIC GRADIENT
RATE OP RUNOFF
DEPTH OP PLOW
SURFACE GEOLOGY
GROUND COVER
LAND USE
ON-SITE EROSION
SHEET EROSION
SEDIMENT PRE-
DICTIVE YIELD
Appendix I, B,l
X
X
X
X
,,
PSIAC
Appendix I, B,2
X
X
X
X
X
X
X
X
X
ROADWAY EROSION
" ROAD DENSITY
Appendix I, C,l
X
. ,v , - -
SURFACE AREA
OP CUT & PILL
Appendix I; C,2
X
X
X
DOWNSTREAM SEDIMENT
DELIVERY
MYER-PETER MULLER
Appendix I, D,l
X
X
X
X
00
-------
182
OJ
u
s
<0
5*
> o
E P
E <
P K
1
M ^
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: i
^ if?
K *
< Z
« o
5 §
^m
m
^
m
«
»
* -
*
rlOO £
a.
r 90
> "
-so :
M
«
.
170 :
- 60 ;
»
.
«
.
-50
m
- "»o ^
]
" * "
1 30 ' :
' *
* >
-zo: ;
1 / -
:
^'10 1
. m
m
r o.o .
»
i r
- O.I
*
- 0.2 /
" t
°x
I *
7-0.4
'
-0.5
- 0.6
t
0.7
-0.8
70.9
*
-1.0
-0
'
^
4
m
4
M
<
«
4
4
1
4PI
*
, 3
*
«
:
* m
- *
*
' * "
0 mt
* *
* ~
* "!
*,-
EXAMPLE *
Ysl.14 "
m
i
i
i
a
^8
-5.0
4.0
n
- 3.0
m
^2.0
«
>
»
-j.O
! **
P »
r
'.
t
- O.O
f^
c
1
ft
u*
3
>? CO
x w
i s
z ^
2 Q
fc LU
fc Ctt ^^
tiJ X
K 2
(9 III
< ^
100 -3
90 :
80 -
70 -
60 -
"SO -
W v <
40 \
30 -j
20 -1
ip..4
-" j
- * "
~~~ IO '
.*" " '
-20-
- *
.'* -3° :
.*' -40 !
* -
, -50 -
* 2
-60 -
0 -j
- I0 ":
?o-
..
*
30 -
A
4O -
Tw t
1 1
: 50 -
M»
: 60 -
: 70 -,
'- 80 -,
90
' 100 -
»
SEDIMENT PREDICTIVE YIELD EQ:
log (Y-HOO) -6.63792-2.13712 log (X,+ IOO)
+0.06284 log (X^-IOO)-O.OI6I6 log (X3+IOO)
4-0.04073 log(X4+IOO
Equation by E. M. Floxman, U.S.D.A. Soil Conservation Service 22/
klAfM/Mir/inh hit U U G«nt*K IICHA Qnil Pnncaruntinn Qaruifa
Figure 38. Sediment Predictive Yield. [8]
-------
Table 25. Sediment Yield Computation Using the PSIAC Method. [24]
Sediment Yield
High
**
Moderate
**
&
Low
A
a. Harine shales
and related mud-
stones and silt-
stones.
a. Rocks of medium
hardness
b. Moderately
weathered
c. Moderately frac-
tured
(0)
a. Massive, hard
formations
B
a. Fine textured;
easily dispersed;
saline-alkaline ;
high sh rink-swell
characteristics .
b. Single grain silts
and fine sands
(5)
a. Medium textured
soil
b. Occasional rock
fragments
c. Caliche layers
(0)
a. High percentage
of rock fragments
c. High in organic
matter
C
(10)
a. Storms of several
days ' duration
with short periods
of intense rain-
fall.
b. Frequent intense
convective storms
c . Freeze-thaw
(5)
a. Storms of moder-
ate duration and
intensity
b. Infrequent con-
vective storms
(0)
a. Humid climate with
rainfall of low
b. Precipitation in
form of snow
c. Arid climate, low
intensity storms
d. Arid climate j rare
D
im
a. High peak flows
per unit area
b. Large volume of
flow per unit
area
(5)
a. Moderate peak
flows
b. Moderate volume
of flow per unit
area
CO)
a. Low peak flows
per unit area
runoff per unit
area
c. Rare runoff
events
E
(20)
a. Steep upland slopes
(in excess of 30 Z)
High relief; little
or no floodplain
development
(10)
a. Moderate upland
slopes (less than
20%)
b . Moderate fan or
floodplain develop-
ment
(0)
a. Gentle upland
slopes (less than
5%)
b. Extensive alluvial
plains
V
UO)
Ground cover does
not exceed 20%
a. Vegetation sparse;
little or no
litter
b. No rock in surface
(0)
Cover not exceed-
ing 40%
a. Noticeable litter
b. If trees present
understory not
well developed
(-10)
a. Area completely
protected by veg-
etation, rock
fragments, litter
Little opportunity
for rainfall to .
reach erodible
material
G
(10)
a. More than 50%
cultivated
b. Almost all of
area Intensively
grazed
c. All of area re-
cently burned
(0)
a. Less than 25%
cultivated
b. 502! or less re-
cently logged
c. Less than 50% .In-
tensively grazed
d. Ordinary road and
other construction
(-10)
a. No cultivation
b. No recent logging
grazing
H
UPLAND EROSION
(25)
a. More than 50% of
the area char-
acterized by rill
and gully or
landslide erosion
a. About 25% of the
area character-
ized by rill and
guLly or land-
slide erosion
b. Wind erosion with
deposition in
stream channels
(0)
a. No apparent signs
of erosion
CHANNEL EROSION &
«|PTrfKT TRANSPORT _
a. Eroding banks con-
tinuously or at
frequent intervals
with large depths and
long flow duration
b. Active headcuts and
degradation in trib-
utary channels
a. Moderate flow depths,
medium flow duration
with occasionally
eroding banks or bed
(0)
a. Wide shallow channels
with flat gradients,
short flow duration
b. Channels in massive
rock, large boulders
or well vegetated
c. Artificially controlled
channels
* THE NUMBERS IN SPECIFIC BOXES INDICATE VALUES TO BE ASSIGNED APPROPRIATE CHARACTERISTICS.
THE SMALL LETTERS a, b, c, REFER TO INDEPENDENT CHARACTERISTICS TO WHICH FULL VALUE MAY BE ASSIGNED.
** IF EXPERIENCE SO INDICATES, ISTESPOLATION BETWEEN THE 3 SEDIMENT YIELD LEVELS MAY BE MADE.
In most instances high values for the A through G factors should
correspond to high values for the H and/or I factors.
PSIAC is an abbreviation for the Pacific Southwest Interagency
Committee.
R,
ating Table
Sediment Yield
Rating
>100
75 - 100
50 - 75
25 - 50
0-25
AF/sq
3.0
1.0 -
0.5 -
0.2 -
<0.2
.mi.
'
3.0
1.0
0.5
AN EXAMPLE OF THE USE OF THE RATING CHART IS AS FOLLOWS:
A watershed of 15 square miles in western Colorado has the following
characteristics and sediment yield levels:
A
B
C
D
E
F
G
H
I
Factors
Surface geology
Soils
Climate
Runoff
Topography
Ground cover
Land use
Upland erosion
Channel erosion
Sediment Yield Level
Marine shales
Easily dispersed, high shrink-
swell characteristics
Infrequent convective storms,
freeze-thaw occurrence
High peak flows; low volumes
Moderate slopes
Sparse, little or no litter
Intensively grazed
More than 50% rill and gully
erosion
Occasionally eroding banks and
bed but short flow duration
Rating
10
10
7
5
10
10
10
25
5_
Total 92
This
total rating of
92 would indicate that the sediment
between 1.0 and 3.0 AF/sq.mi. based on Rating Table.
yield is
CO
u>
-------
184
RELATIONSHIP BETWEEN ROAD DENSITY AND SEDIMENT PRODUCTION
7
8 10 12
ROAD DENSITY
Miles Per Square Mile
Figure 39. Road Density and Sediment Production. [30]
-------
185
200
100
90
80
70
60
SO
40
V)
£30
O
20
<
UJ
o:
UJ
§ 9
V) 8
7
6
5
SLOPE OF CUT AND FILL
(HORIZ.:VERT.)
VERTICAL HEIGHT OF
CUT AND FILL IN FEET
1.5=1 2,|
i i iii
WIDTH OF ROAD; 20FEET
ROAD GRADIENT: 0%
ROAD LENGTH : I MILE
i i i i i
6 7 8 9 10 20 30 40 50 60 7O8090IOO 200
GROUND SLOPE IN PERCENT CHART BY PERRY v. AMIMOTO
DIVISION OF MINES AND GEOLOGY
Figure 40. Surface Area of Cut and Fill Per Mile of Road in Acres. (Road Width of 20 Feet)
-------
186
200
100
90
80
70
60
50
40
UJ
tc
O
20
Ul
pc
UJ
~> 9
« 8
7
6
5
4
SLOPE OF CUT AND FILL
(HORIZ.: VERT)
VERTICAL HEIGHT
CUT AND FILL I
ROAD GRADIENT : 0 %
: 60 FEET
MILE
i I t i i
6 7 8 9 IO 20 30 40
GROUND SLOPE IN PERCENT
5O 60 708090100 200
CHART BY PERRY Y. AMIMOTO
DIVISION OF MINES ANDGEOUOGY
Figure 41. Surface Area of Cut and Fill Per Mile of Road in Acres. (Road Width of 60 Feet)
-------
187
zoo
100
90
BO
70
60
50
40
UJ 30
a: 30
o
20
UJ
cc.
IL)
o
SLOPE OF CUT AND
FILL(HORIZ. :VERT.)
&
&\J
'W-'
VERTICAL HEIGHT OF '<>o \ Vs.
CUT AND FILL IN FEET « \ M\/
\ \ /\
WIDTH OF ROAD: 100FEET
ROAD GRADIENT : 0 %
ROAD LENGTH : I MILE
i
i i
5 6 7 8 9 10 20 30 40 SO 60 7O 809OIOO
GROUND SLOPE IN PERCENT
200
CHART 8Y PERRV Y. AMIMOTO
DIVISION OF MINES AND GEOLOGY
Figure 42. Surface Area of Cut and Fill Per Mile of Road in Acres. (Road Width of 100 Feet)
-------
188
I0,000r
.10.09.08.07.06 .05 .04 .03 .02
1,000
J 100
o
£
O
o
o
4)
a
in
c
o
ce
2
UJ
2
O
UJ
Assumptions
1-0 m m
r ,5mm
.3 .4 .9 .6 .7 .8 .9 I. 2.
DEPTH OF FLOW (d) IN FEET u.
ri_v« \u) IIM rtc.'
3.
.01
.009
.008
.007
.006
.005
.004
.003
.002
.001
.0009
.0008
.0007
.0006
.0005
.0004
.0003
.0002
.0001
Meyer-Peter and Muller Equation: 9,= 1.606 [i.306 &) (-^?dS-0.627oJ?
Figure 43. Meyer-Peter and Muller Method.
5. 6. 7. 8. 9. 10.
COMPUTER ANALYSIS AND
CHART BY PERRY Y.AMIMOTO
DIVISION OF MINES AND GEOLOGY
20.
-------
189
APPENDIX II. CLIMATE, RUNOFF, ALLOWABLE VELOCITIES
A. Estimating Start and End of Rainy Period
B. Freeze-Free Period
C. Detenccii.-..:;: Rate of Rainfall Runoff
D. Allowable Velocities for Unlined Earth Chan-
nels
A. Estimating Start and End of Rainy Period
Table 26. "Estimating start and end of rainy
period," may be used as a guide to
determine the earliest start and lat-
est finish of construction activities.
For example, if at Escondido the decision is
made to limit construction activities to the time
when the rainfall is less than one inch (for two-
week periods), the allowable construction period
would be from March 29 to November 22.
B. Freeze-free Charts
Freeze-free charts are useful for irrigated seed
or shrubs which are grown during the period
when the plants are susceptible to frost damage.
The charts indicating the occurrence of the
dates of freezing temperatures in California are
shown in Figures 44 to 47.
C. Determining Rate of Rainfall Runoff [35]
The California Division of Highway's nomo-
graph (Figure 48) provides an estimate of the
rate of rainfall runoff in watersheds of less than
5 square miles and where reliable rainfall inten-
sity and runoff records are unavailable.
This method is based on the rainfall intensity to
be expected for given regions during a 60-
minute period on an average of once in 100
years.
The following criteria should be considered
when using the nomograph:
1. If the basin is not pear-shaped or if the road-
way drainage systems are present, the time
of concentration changes and the correct
runoff is obtained by entering the chart with
a computed time of concentration.
2. Using the full time of concentration for the
entire area of drainage does not necessarily
result in the maximum possible design peak
discharge.
3. Table 27 shows values of coefficient of run-
off - "C".
4. Various shorter storm durations, combined
with the area contributing during each
shorter time of concentration, should be in-
vestigated sisee the resultant higher intensi-
ties over partial areas may produce larger
dis:!ie ges See California Culvert Practice
and FHWA Highway Engineering Circular
No. 12.
5. The highest runoff factor and the shortest
time of concentration resulting from the an-
ticipated developed condition during the de-
sign life of the project should be used.
D. Allowable Velocities for Unlined Earth Chan-
nels [51]
Figure 49, "Allowable Velocities for Unlined
Earth Channels," provides a means of deter-
mining whether a channel or a discharge area
should be lined or unlined.
The factors used to determine allowable velocit-
ies are:
1. Soil Type (Uniform Soil Classification
System)
2. D75 -Particle Size
3. Channel Configuration
4. Flood Frequency and Design Flow
The allowable velocities for unlined earth chan-
nels assumes no protection against erosion by
vegetation along the waterway. There may be a
conside>fvu;y/f.- for higher design velocities if ade-
quate vegetation can be established before runoff
is permitted within the channel.
-------
Table 26. Estimating Start and End of Rainy Period.
LOCATION
NORTH COASTAL AND
SIERRA NEVADA RANGE
CENTRAL AND SOUTH COASTAL.
CENTRAL VALLEY, N.E. CALIFORNIA
ARID AND
DESERT REGIONS
.16 0.00
.06 0.00
Note:
I. Data is mean precipitation for two
week periods in California. 59/
2. Chart designed by Perry Y. Amimoto,
Division of Mines and Geology.
.5- 1.0"
.25"-.5"
-------
191
Figure 44. Average Dates of First Frost in Autumn. [7] [53]
-------
192
'NOV. I
IOV.I5
Figure 45. Earliest Date of First Frost in Autumn. [7] [53]
-------
193
MAR.
EB.I5
Figure 46. Average Date of Last Frost in Spring. [7] [53]
-------
194
JUNE I
HAY IS1
MAY I ,
APR. 15
APR. I
APR.I
MAR. 15
MAR.15
Figure 47. Latest Date of Last Frost in Spring. [7] [53]
-------
EXAMPLE:
A culvert site in the Imperial Valley is 3 miles downstream and 900 ft. lower than the most
remote point on the watershed. The tributary basin has an area of 2.0 square miles and an
average ratio of coefficient of runoff to precipitation is estimated at .60.
5000
-tooo
£ looo
o ~
(X
500
MO
5
ex
50
a
II
E ~
to
10
9 ^j,,,
Miles.
Most
Pemote
Point
in Time
The line through H = 900 ft., L = 3 mi.. Geographical Classification (G = Q), A = 2 sq. mi.
and C = .60 intersects Q = 1700 second-feet the required design discharge.
Incidentally, the flow results from a 41 minute storm of 2.2 inches per hour.
il
c o
c o.
0 o
o «
Feet
I - 5000
<"- -1000
0.1- _
-zoo
GEOGRAPHICAL
CLASSIFICATION
s-
10-
100 -
500-
2 jqste
5000-
loooo
O *
O
o
a
^
i
-10
I-10
to
-so
-100
too
-SCO
-1000
§1-2000
«*-,
o
*-
* -5000
O .
V .
a
-10000
Acres" Sq. Mi.
10000-
5000-
looo-
500-
US,
-.10
o
o
100-
50-
Figure 48. Determining the Rate of Rainfall Runoff Using the California Division of Highways Nomograph. [35]
ui
-------
196
Table 27. Value* of Coefficient of Runoff"C". [25]
Land Use
IMPROVED
UNIMPROVED
Surface Condition
Roof Surfaces
A.C. or P.C.C. Pavement, patios,
driveways, streets, sidewalks
Landscaped areas
Gravel walks, roadways
SLOPE
SUB-
DRAIN-
AGE
VEGE-
TATIVE
COVER
DRAIN-
AGE
CONDI-
TTHNT
JLJ.ULM
Above 30$
~LQ% - 30%
$% - 10*
0 - 5*
Bare rock or very thin soil.
Impervious clays, shallow
soils .
Well drained soils.
Deep sand, volcanic ash.
None c-r very sparse.
Less than 2Q% covered with
substantial growth.
About 50$ covered with
heavy growth.
9Q% covered with heavy
growth, deep humus layer.
Smooth soil, slick rock,
drainage flow continuous.
Roughened soil or rocks
Drainage flow arrested,
large lakes, ponds, marshes.
Drainage flow interrupted,
many ponds, lakes, marshes.
»C"
.90
.85
.25
-30
.32
.2lj
.17
.11
lit
.10
.07
.05
.lit
.10
.07
.05
.11
.09
.07
.05
Example Computation
20 acre tract
3 acres roof @ .90
10 acres A.C. Pave. @ .85
7 acres landscaped @ .25
C=3 x .90 + 10 x .85 + 7 x .25= 0.65
20
20$ Slope ,2k
Well drained soil .07
Fair cover \ .07
No ponds .07
0= .Lt5
Derived from Placer County "Land Development Manual" 257
-------
FREQUENCY OF DESIGN FLOW
Ittni.i'H'l
145678
Flood Frequency in Percent Chonce
' 16 14 12 |0 8 6
Curve Radius - Water Surfoci Width
Cotangent of Slope Angle
(Z)
5 6 7
Water Deoth in Feet
MOM-SCOURING VELOCITIES FOR VARIOUS EARTH MATERIALS
SOIL
Stiff clay, high cohesion
Lean to moderately co-
healve clays; stlty or
sandy clays.
Colloidal alluvial silts;
micaceous or diatomaceous
silts; organic silts and
clays with high LL.
Non-colloidal r luvial
silts; sandy or clayey
silts; organic silts with
low LL.
Silty sands or gravelly
silty sands containing
more than SZ fines .
Clayey sand or gravelly
clayey sands containing
more than Si fines.
Clayey gravels or clayey
sandy gravels containing
more than 57. fines.
Silty gravels or silty
sandy gravels containing
more than SX fined.
Clean sands and gravels
or sand-gravel mixtures
containing less than 5Z
fines.
SOIL
CLASSI-
FICATION
GROUP
CH
. CL,
CL
CL
HH,OH
MH.OH
MH.OH
ML.OL
ML.OL
SM
SM
SC
SC
SC
GC
GC
GC
CM
GH
GW
GF
SW
SP
PI
Above
20
7-10
10-20
Above
JO
Below
10
10-20
Above
20
Below
HO
10-20
Below
10
10-20
7-10
10-20
Above
20
7-10
10-2^
Above
20
Below
10
10-20
-
.
-
VELOCITY (FT. /SEC.)
CLEAR
WATER
4.5
Curve 1
2.5
4.0 '
Curve 1
2.5
3.5
Curve I
2.5
Curve 1
2.5
Curve 1
2.5
4.0
Curve 1
Curve 1
or 4.0
Curve 1
or 5.0
Cv « 1
SJTo1
Curve 1
Curve 1
Curve 1
Curve 1
SUSPENDED
LOAD
6.0
Curve 2
4.0
5.5
Curve 2
4.0
5.0
Curve 2
4.0
Curve 2
4.0
Curve 2
4.0
6.0
Curve 2
Curve 2
or 5.5
Curve 2
or 6.5
Curve 2
SSTTj*
Curve 2
Curve 2
Curve 2
Curve 2
BEDLOAD
3.5
*
2.5
3.5
*
2.5
3.0
*
2.5
*
2.5
*
2.5
3.5
*
*
or 5.0
*
or 6.0
*
*
or 5.5
*
130
Enter chart with 675 particle size
to determine non-scouring velocity
Grain Size in Inches
DESIGN VELOCITIES FOR UNLINED EARTH CHANNELS
TYPE OF FLOW
Sustained Plow
Intermittent
Flood Flow
SOIL GROUP
Non-Cohesive
Cohesive
Non-Cohesive
Cohesive
ALLOWABLE DESIGN VELOCITY
Chare value x D x A x B
Tabular value x D x A
Chart value x D x A x fc
Tabular value x D x A x F
*Use curve number 1 if the bed load con-
centration is leas than the capacity of
the stream or If the size of the bed
load material is larger than the 875
size of the channel materials. Use
curve number 2 if the bed load concen-
tration is equal to the capacity of the
stream or if the size of the bed load
material ia smaller than the 075 size
of the channel materials.
Note:
In no case should the allowable velocity
be exceeded by the 107. chance discharge
regardless of the frequency of. occurrence
of the design flow.
Figure 49. Allowable Velocities for Unlined Earth Channels. [51]
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
REPORT NO.
EPA 4 40/3-78-003
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
"Erosion and Sediment Control Handbook"
5. REPORT DATE
y. 1977
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Perry Y. Amimoto
8. PERFORMING ORGANIZATION REPORT NO
9. PERFORMING ORGANIZATION NAME AND ADDRESS
California Department of Conservation
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AND PERIOD COVERED
Nonpoint Sources Branch, Water Planning Div.
U.S. Environmental Protection Agency
Washington, D.C. 20460 /
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This handbook provides the procedures by which physical and
climatic data and erosion control practices can be considered
in making an assessment of the site for determining the need
for an erosion control plan and for preparing an erosion control
plan.
The required content of an erosion and sediment control plan is
presented in a chapter including a Model Erosion Control
Ordinance. An orderly set of procedures is provided to serve as
a regulatory function in approving applications for proposed
developments and as a means of applying information from chapters
on Erosion Control Practices.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Construction, sediment, pollution,
management
Pollution Control
Nonpoint Sources
Water Pollution
-1302.2
8. DISTRIBUTION STATEMENT
For Public distribution by the State
of California
19. SECURITY CLASS (ThisReport)
21. NO. OF PAGES
20. SECURITY CLASS (Thispage)
22. PRICE
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION is OBSOLETE
*U.S. GOVERNMENT PRINTING OFFICE: ,978-260-880/63
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ACKNOWLEDGMENTS
The State of California and the California Associa-
tion of Resource Conservation Districts gratefully
appreciate the effort by Robert E. Thronson, Project
Officer for EPA, to publish this handbook.
Special recognition is made to B.L. Kay of the
University of California at Davis for his significant
contribution on the descriptions of mulches and
vegetation for use throughout California. Also grate-
ful appreciation is made to A.T. Leiser of the Univer-
sity of California at Davis for providing information
on the planting of shrubs in the Lake Tahoe region.
Agencies and persons that have contributed to or
have reviewed the report include the following:
United States Department of Agriculture, Soil
Conservation Service
Environmental Quality Committee of the Califor-
nia Engineers Association
California Resource Conservation Commission
United States Environmental Protection Agency
California Division of Highways
California Department of Forestry
States of Washington, Utah, New Jersey, Mary-
land, Pennsylvania, Hawaii, and New Mexico
Elliot M. Flaxman, United States Department of
Agriculture, Soil Conservation Service, Port-
land, Oregon
Tahoe Regional Planning Agency, South Lake
Tahoe, California
County of Placer, Department of Public Works,
Auburn, California
The author appreciates the information provided
by many firms associated with the products men-
tioned in this handbook. However, the use of trade,
firm, or corporation names in this publication is for
the information and convenience of the reader.. It
does not constitute an official endorsement or ap-
proval of any product or service to the exclusion of
others that may be suitable.
The final preparation of illustrations and charts
was provided by the California Division of Mines
and Geology, Sacramento.
Back Cover - Placer County Department of Public Works
California Department of Fish and Game
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EROSION
-
SEDIMENT
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