EPA-908/3-80-001 A
Volume 1: Assessment of Nonpoint Sources
UPPER EAGLE VALLEY
NONPOINT SOURCE ASSESSMENT
AND CONTROL PLAN
FEBRUARY 1980
PREPARED FOR
U.S. Environmental Protection Agency
Region VIII
BY
ENGINEERING-SCIENCE, INC
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UPPER EAGLE VALLEY
NONPOINT SOURCE ASSESSMENT
AND
CONTROL PLAN
Volume 1: Assessment of Nonpoint Sources
Prepared for the
U.S. Environmental Protection Agency
February 1980
by
Engineering-Science
125 West Huntington Drive
Arcadia, California 91006
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DISCLAIMER
.This.report has been reviewed by the U.S. Environmental Protection Agency,
and approved for publication. Approval does not signify that the contents
necessarily reflect the views and policies of the U.S. Environnental Protection
Agency, nor does mention of. trade names or ccnmercial products constitute endorse-
ment or reccnmendation for use.
Document is available to the public through the National Technical
Information Service, Springfield, Virginia 22161.
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TABLE OF CONTENTS
Page
Acknow1edgment
SECTION I INTRODUCTION 1
SECTION II BACKGROUND 2
SECTION III OBJECTIVES 5
SECTION IV STUDY AREA OVERVIEW 6
Water Quality Assessment 7
Water Quality Problems
Runoff Conditions 13
Summary 1^
SECTION V SOIL EROSION
Erosion Processes 15
Study Area Experience 21
Predicting Soil Erosion 27
SECTION VI URBAN RUNOFF 30
Processes 30
Sampling Program 37
Assessment ^0
SECTION VII NONPOINT SOURCE CONTROL 49
Pollutants from Construction 50
Pollutants from Areas of Human Activity 60
Control Techniques 70
REFERENCES 72
APPENDIX A WATER QUALITY DATA 75
APPENDIX B EXAMPLE GRADING ORDINANCE 88
ii
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LIST OF FIGURES
So.
Title
Page
1
Change in Slope Coefficient with Change in
19
Slope Percentage
2
Change in Vegetative Cover Coefficient with
19
Change in Vegetative Cover Percentage
3
Effect of Watershed Size on Sediment Delivery
20
Ratio
4
Weekly Water and Sediment Discharge during
22
Spring Runoff in Gore Valley
5
Solids Accumulation for Different Land Use as a
32
Function of Time
6
Percentage of Pollutants Removed During Runoff
34
7
Concentrations of Lead in Snovmelt Runoff in
36
Denver, Colorado
Plates may be
found in pocket at end of Volume I:
Plate 1
Study Area Overview
Plate 2
Water Quality
Plata 3
Vegetation and Soil Disturbance
Plate 4 Runoff Factors and Influences
111
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LIST OF TABLES
No.
Tide
Page
1
Selected Colorado Water Quality Criteria
9
2
Gore Valley Annual Water and Sediment Yields
23
3
Gore Valley Drainage Basin Areas
23
4
Sediment Yield Rates from 1-70 Construction Sites
26
5
Example Sediment Yield Calculation
29
6
Loading Rates—Ranges of Reported Data, and Values
35
used in Colorado for Comparable Land Uses
7
Water Quality Characteristics of Urban Runoff
38
8
Urban Runoff Water Quality Measurements in
39
Colorado Mountain Resorts
9
Summary of In-Stream Water Quality Data Obtained
42
Spring 1978, Upper Eagle Valley, Colorado
10
Land Use Distribution of Runoff Sampling Point
45
Tributary Areas
11
Estimated 1978 Average Daily Pollutant Loads-
48
Gore Valley
12
Estimated Annual Average Gore Creek In-Stream
71
Concentrations
iv
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AO30WIEDGMEHT
The project officers for Che U.S. Environmental Protection
Agency were Messrs. Robert Doyle, Thomas Elaore, and Richard
Claggett. Their continuing support and active participation in
the conduct of this study was instrumental in its successful
completion. The author would also like to acknowledge the im-
portant guidance provided by the Management Team.
This report was authored by Mr. Phillip J. Morris, Chief
Environmental Analyst, and the manuscript prepared by Money
Stapleton, Sam Ellsworth, Leda Davidson, and Selen McGehee.
v
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Site preparation ex-
poses large areas of
soil to wind and water
erosion
Runoff from construc-
tion sites washes soil
into nearby streams
Silt deposited in
stream beds smothers
vegetation and kills
aquatic life
vi
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Sediment reduces the
effectiveness of storm
drainage and flood
control structures
Pollutants are de-
posited on roads and
parking lot by
vehicles
Pollutants from vehicles are washed
off by snowmelt and rainfall
vii
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Sand, ash and deicing
chemicals are washed
off into drainage
ditches and streams
during snowmelt
Leachate from mine
tailings ponds finds
its way into Cross
Creek
Unrestricted dumping
into drainage ways lead
to stream pollution
viii
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Dumping of waste oil, paint and other materials
on stream banks directly pollutes the stream
Construction debris, such as this along 1-70,
may be a source of pollution for many years
ix
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Improperly stored hazardous and toxic materials
contribute to runoff pollution
An accidental spill from this container would
flow into Gore Creek
x
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SECTION I
IHTaODUCTION
The quality and quantity of water determines stream uses. A stream
may be used as a domestic water supply, to support recreation, for crop
irrigation, or to maintain a habitat for fish or other wildlife. The
quality of water in a stream depends upon the amount of pollutants
entering the stream, and the capacity of the stream to cleanse itself.
The sources of pollutants entering a stream can be divided into two
types which are called point sources and non-point sources. Point
sources are facilities where a collected and controlled water supply has
been used before being discharged to a stream. An industrial plant is
an example. Notr-point sources are diffuse and generally uncontrolled
such as rainfall runoff or seepage from groundwater. This study is
primarily concerned with existing and potential non-point sources of
water pollution in the Upper Eagle Valley of Colorado. See Plate 1.
1
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SECTION II
BACKGROUND
This study Is la large measure a consequence of planning and In-
vestigations carried out under the requirements of Sections 201 and 208
of che U.S. Clean Water Act, and the National Environmental Policy Act
(1TEPA). Planning under Section 201 Is called facility planning and has
the objective of determining what wastewater treatment facilities would
best meet che future population demands of an area served by a public
agency, and meet the water quality standards. Subsequent steps under
section 201 involve the design and construction of needed facilities.
Thus section 201 is concerned with publicly owned poiac sources of
pollution. Section 208 othe Clean Water Ace requires che development
and annual revision of areawlde vacer quality aanagemenc plans which
consider all types of pollution sources. These areawlde plans establish
regional strategies whereby cne water quality goals of an area are
achieved and maintained.
The Town of Vail and the Upper Eagle 7alley Sanitary District
provide sewage service to the study area. A facility plan addressing
the needs of this area was completed in 1976. The U.S. Environmental
Protection Agency (EPA) coopleced an Environmental Impact Statement
(EIS) on che facilities recommended in che facility plan later chat same
year. AC the same ciae, the development of an areawlde water quality
management plan was proceeding. This plan was being developed by che
North West Colorado Council of Governments (NVCCCG) for an area of
Colorado which covers the counties of Eagle, Grand, Jackson, Plcian,
Routt, and Summic.
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The SIS concluded, supported la part by preliminary results from
cha ongoing areawide planning prograa, that Che proposed facilities
would reduce poiac source pollucioa discharges to Gore Creek, and Eagle
itiver and improve she water quality. The SIS went on to state that
there are Indications as to the general significance of current non—
poiac sources or pollution, and chat increases ia non-point pollution
attendant wich further development in the valley could threaten the
maintenance of water quality achieved through improvements in the
quality of poiac source discharges. See .References 1 and 2. As a con-
ditioa of approval of the facilities plan aad subsequent EPA funding of
design and construction, EPA required chac the cown of Tail and che
Upper Eagle Valley Sanitary District participate la an EPA study of
aoa-poiat source problems aad their potential solutions. EPA sigaed
agreements with a number of agencies calling for their participation in
this study, aad foe che agencies to actively pursue iapleaeatation of
the non-point source control recommendations of this study. Agreements
were signed wich che Town of Vail, Town of Miatura, Upper Eagle Valley
Sanicacion Discricc, Vail Water and Sanicacion District, Eagle County,
NWCCOG, and the State of Colorado.
This study was funded and organized by EPA in lace fall of 1977. A
management ceam was established co guide EPA aad ics contractor
Engineering-Science, Inc. in the conduct of this study, and so co-
ordinate che accivieies of and periodic reviews by che members. The
Membership of che management team is:
Mr. John Dobsoa
Mayor
Town of Vail
Mr. Terrel J. Miager
Town Manager
Town of Vail
Mr . Dennis Murphy
Environmental Health
Officer
Town of Vail
Mr. Erik Edeen
Environmental Healch
Officer
Eagle Councy
Mr. Terryl Kaighc
Councy Planner
Eagle County
Mr • John V. Aaaco
President
Upper Eagle Valley
Sanicacion District
Mr. Thomas Elmore
208 Coordinator
MWCCOG
Mr. Kan Webb
Colorado Water Quality
Control Commission
Mr. Gary 3roetzman
State 208 Coordinator
Governor's Office
3
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Mr. Harold SI. Bellua
Mayor
Town of Miaeura
Mr. Jla Collln.3
Manager
tipper Eagle Valley
Sanitation District
Mr. Ernie Jfuaa
District Ranger
CJ. S• forest service
Mr. Sob Manzaaarea
town Manager
Town of Miatura
Mr. Larr? Burdieic
President
Vail Water ana Sani-
tation Discrice
Mr. Richard Claggett
Project Officer
U.S. EPA Sagion Till
He. Keith Troxei
Chairman, Eagle Count?
Soard of Consaissloaera
Mr. Kant Sase
Manager
Vail Water and Sani-
tation District
Mr. Phillip J. Morris
Project Manager
tngineeritig-Scieoca,
Inc.
4
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SECTION III
OBJECTIVES
The objectives of this study are:
A. Detailed identification of existing aon-point source pollution
problems within the Upper Eagle Valley. Source categories to
be considered include, but are not limited to, urban runoff,
construction activity (highway and urban development), highway
runoff and mining activities•
3. Detailed identification of potential aon-point source pollution
problems within Upper Eagle Valley.
C. Development of sice specific solutions for problems identified
in objectives A and B that are needed to significantly reduce
non-point source pollution and to meet water quality standards.
D. Development of recommended management systems, model regula-
tions and guidelines for use by local agencies to implement
solutions to aon-point source pollution problems.
E. Assessment of existing land use policies and plans and recom-
mend any changes which would mitigate aon-point source pollu-
tion problems.
All recommendations for actions by local agencies oust be compat-
ible with established water management and recreation objectives, and
should be developed in consultation with the public and public agencies
to assure a high degree of public acceptance. This study will build on
the results and recommendations of the North West Colorado Council of
Governments' Areawide Water Quality Management Plan.
5
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SECTION IV
STUDY AS£A 0VEVI2V
The 3cad7 area is abouc 100 miles west of Denver and la the Upper
Eagle Valley of Sagle Councy, Colorado. The study area boundaries are
defined by the drainage basins of the Eagle River and its tributaries
for the reach from Gilman to Avon, and has an area of 246 square ailes ¦
The topography of the area Is typical of mountainous areas with the
majority of the study area having elevations between 3,000 and 12,000
feet, with 30-40 percent of the area dominated by slopes greater than 40
percent. The annual average precipitation in tne study area is about 2S
laches of which wo-thirds falls as snow. Although there is ample pre-
cipitation for vegetation, seasonal temperature norms result in a grow-
ing season that Is only about 100 days long. Nevertheless, forestlands
dominate the area below timberline (about 12,000 feet), and above the
valley floors. The slopes facing a northerly direction have the most
vigorous growths of aspen and evergeen forests, while southerly facing
slopes are sparcer and more often dominated by shrubs and grasses.
There are tvo major tributaries to the Sagle River as it passes
through che study area. These are Gore Creek and Cross Creek. The
drainage basin of Gore Creek has an area of 105 square miles, and che
Cross Creek basin has an area of 34 square miles. These basins are 43
percent and 17 percent, respectively, of che total study area. The
remainder of the study area drains directly to the Eagle River or is
drained by several minor tributaries- Channel slopes vary between 1 and
14 percent on Gore Creek, 3 and 10 percent on Cross Creek, and 1 to 2
percent on the tagle River. The peak flow3 In the streams of the study
area occur during snownelc runoff In lace spring. The aoachly discharge
for che lagle River during water year 1973 at Gypsum, 25 miles down-
stream of the study area, indicates chac abouc 7 5 percent of che total
annual discharge occurs during May, June, and July. See Place 1.
6
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The majority of the study area, 38 percent, is in the Vhite River
National Forest. The remainder is within the jurisdiction of iagla
County and the Towns of Vail and Hiatura. The area is served by later-
state Highway 1-70 and U.S. 24, and by the Denver, Rio Grande and West-
ern Railroad. Light aircraft and commuter flights are expected to use
the airport at Sagle-Vail. Virtually all development is confined by
terrain to the Gore Creek and Eagle River valley floors. Upstream of
the confluence of Gore Creek and Eagle River, ehe valley floors are
narrow, about 3,000 feet wide. However, Che Sagle Valley widens con-
siderably downstream of Gore Creek.
Development of recreation facilities stimulated growth in che area
beginning in 1972. The growth in permanent population betveen 1968 and
1978 was almost 12 percent per year. The increase in average daily pop-
ulation during che same years was nearly 10 percent per year. The aa-
joricy of this growth has occurred in the Gore Valley. Future growth i3
expected co be centered in che Avon area. References 1 and 2.
Gore Creek, Cross Creek, and che Sagle River are all used for domescic
water supply. Groundwater supplies are used to a limited extent mostly be-
cause of che abundance of surface wacer, and partially because groundwacers
are hard. The alluvial aquifers of che valleys are fast in that percola-
tion races are high in subsurface soils. Vater levels in wells near
streams fluctuate in response to changes in scream wacer levels. Aluvial
groundwater aquifers are recharged by infiltration from che ground surface
and screams during snowmelc runoff. These aquifers discharge co streams
during normal or low flow periods. A significant portion of annual stream
flow aay come from infiltration of groundwater into streams.
WAIZH QUALITY ASSESSMENT
The wacer quality in che area has been investigated on a number of
occasions in che lasc 10 years. The aosc recenc was in support of che
NWCCOC's areavide water qualicy management planning. See References 3
and 4. The conclusions of chese invescigacions aust be modified co some
extent to account for new '
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Wacer quality standards are related to the water use goala estab-
lished for a scream. For example, If a scream is only going co be used
for agriculture, then Its quality does aoc have Co be as good as it
would have co be If It were also co be used for doaesclc vaeer supply.
The recommended use goals for ehe screams of Che scudy area ara body
contact recreation, domestic water supply, cold water blocs and agri-
culture. See Reference 2. All screams except Cross Creek would be
classed for Class I cold vacer bloca. Cross Creek would be classed for
Class 2 cold water bloca which 3lmply means scream conditions or wacer
quallcy may exceed Class 1 criteria, thus ancldegradacloa policies are
in effect until special criteria can be established.
The Colorado Vacer Quallcy Control CoBimtssioc has established
general wacer quallcy criceria chac would Insure chat che wacer quallcy
of screams peralt che uses for which goals have been established. See
Reference 5. At some ciae in the future, the Colorado Vacer Quallcy
Concrol Comission will hold hearings on che recommended use goals for
the study area's screams, and establish numerical standards for wacer
quality. The general criteria adopted by the Cotzniaslon will be modi-
fied as appropriate based upon these hearings, and adopted as wacer
quallcy scandards for che area's screams. Vacer quallcy criceria se-
lected from che Commission's criteria for various stream uses are given
in table 1. Aside from chese numerical criceria, che Commisssion had
adopced an ancidegradacion policy for existing high quality waters.
Numerical criceria have eoc been established for suspended solids (SS),
tocal dissolved solids (TDS) or for fecal screpcococcus (tS). These
parameters have been investigated during past wacer quallcy investi-
gations in che study area. Therefore, some criceria Is desirable in
order co assess che resulcs of chese lnvesclgaclons• Vacer Quality
Commissioo working papers have suggested chac suspended solids con-
centrations be limited to a 20 co 30 percent Increase foe screams
classed for vacer supply and agricultural uses. The cricaria would be
applied as streams pass through an "impact" area where nan-induced
changes ara affecting suspended sediaenc concentrations. Suspended
solids can adversely affect water treatment facilities by thwarting
disinfection processes, and can adversely affect high quality aquatic
3
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TA3LZ 1. Selected Colorado Water Quality Criteria
Parameter
elm I«
3047 unuc:
raeraaeioa
4CW
aucply Agriculture
Pfrvalcal (af/1 unlui aoead)
OlMol*«d oxygen, tlnlmnm
j3 (leindard vales)
lamparaeure, niiumn
TaHe 'iataLi (uj/1 snicta
aocad)
(solobl*)'1
Arsealc
iarlum
SasylXios
Giromlua
Capper
iron
Lud
Sagnaaese
Karcury
Molybdenum
Mlekal
Selealwa
Silver
tiailim
(Irani
line
Otaar Toxicants (mg/l -jnlui
aacad)
» (unlooiied *a
CSlariaa (cataj. residual)
Cyanide
Hleraee (u 3iersg«n)
Sluice (*a 31;rs?«a)
Suli'de V4J HjJ)
7 for ipawn
4.3 - 9
:o*c
100
20
10
0.4
100
10
1,000 (eaeal)
4
1,000
0.03
30
20
0.1
ls
30
30
0.02
0.002
0.003
0.03
0.002
(uadlisoclited)
4.3 - 3
2
J - 9
30
1.000
10
30
1,000
100
100
10
100
:oo
300(soluaie) -
30
30
2
10
30
10
1
0.05
100
:oo
uo
200
20
2,000
100
10
laarsaoic llaarala (mg/1
unleaa aoeea)
CUociie
Sajneslum
Sulfate
230
123
230
ilological
?eeal coLiiaraa ?er
100 aiHUitras
200
1,000
1,000
1 Tin icuaci: liie jcaodaria far :axic seeala »r« far
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biota. Therefore, a criteria of 25 mg/1 and a 20 percent change in
concentration will be used to assess water quality in this study. The
U.S. drinking water standard of 500 mg/1 ICS will also be used, as will
the former Colorado standard of 20 FS/100 ml.
These standards were compared with available water quality data,
and violations noted. The results of this comparison are displayed on
Plate 2. Violations were noted whenever the standards established for
this assessment were equalled or exceeded.
The frequency and distribution of violations as veil as observa-
tions by previous investigators suggest several trends and conclusions.
The screams of the area are generally low in hardness. Values of hard-
ness infrequently exceed 100 mg/1 except in the Eagle River below Gore
Creek. Beaver Creek is also an exception wherein normal hardness levels
frequently exceed 100 mg/1. Hardness is important as it dictates the
allowable concentrations of several toxic metals in the State criteria.
The pH of the screams varies routinely between 7 and 3.5 and frequently
up to a pH of 10. The levels of dissolved oxygen are generally about 7
mg/1 during the summer and increase to as much as 12 ag/l during the
winter months* These levels are characteristic of mountain streams
where channel slopes promote turbulent flow and aeration. Violations of
DO standards have been recorded in Gore Creek at its mouth and in the
vicinity of the Bighorn subdivision east of Vail. DO levels below 4
mg/1 were measured, however such results appear atypical compared to
other investigations.
Except for alack Gore Creek and Mill Creek, the tributaries of Gore
Creek have high quality water. Slack Gore Creek has had high levels of
suspended solids for the last several years, particularly during spring
runoff. As a consequence, levels in Gore Creek have been increased.
One sample from Mill Creek contained cadmium in excess of standards.
3acteria levels in Gore Creek have frequently exceeded criteria for body
contact water recreation. Toxic levels of un-ioaized ammonia in the
lower reches of Gore Creek below Vail are frequent and well documented.
The remaining violations on Core Creek involved the toxic aetals lead,
cadmium and manganese. The violation of the nitrite standard in Gore
Creek near its confluence with 31ack Gore Creek is unusual in that
10
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aitriee Is usually quickly oxidized co less toxic nitrate in veil
aerated streams.
The tributaries to the Eagle River except Cross, Gore, and 3aaver
Creeks have good vater quality. Gore Creek has been discussed. Beaver
Creek has high but acceptable hardness, alkalinity and total dissolved
solids levels especially during spring snowmelt runoff. Sigh concen-
trations of iron, cadmium and sanaganese have been measured in Cross
Creek above the New Jersey Zinc mining area. The vater quality in the
Eagle River as it flows into the study area is generally good altho'ugh
occasional problem with toxic aetals and bacterial contamination have
been recorded. Betveen Cross Creek and Avon the vater quality is
severely degraded, though data and investigations indicate that the
quality has improved in recenc years particularly betveen Cross Creek
and Gore Creek. Nevertheless, as late as 1976, violations of standards
have been recorded for suspended sediment, cadmium, iron, lead, man-
aganese, zinc, fecal collfora and fecal sterptococcus downstream of Gore
Creek.
WATER QUALITY PR0BL21S
The construction of Interstae Route 70 through the Black Gore Creek
basin is the cause of high suspended sediment levels in Black Gore Creek
and consequently in Gore Creek. Highway construction and urban develop-
ment in the Gore Valley have independently contributed to high suspended
sediment levels in Gore Creek. The toxic levels of un-ionized ammonia
in the lower reaches of Gore Creek are caused by discharges from the
Vail sewage treatment plant. The plant also contributes to the bac-
terial count in Gore Creek, however non-point sources appear to be the
sajor contributors. These non-point sources are principally runoff from
wildlife and range areas, urban runoff and possibly old, failed, or
abandoned septic tank and leach field systems. This latter source is
the possible explanation for the high nitrite level (0.03 og/1), and
high fecal coliforn and sterptococcus counts (each 315 MPM/100 al)
measured in Gore Creek upstream of Black Gore Creek, but downstream of
the camoground identified on Plate 1. The violations of criteria for
cadmium, lead and nanganese in Gore Creek all occurred during spring
II
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runoff. High background concentrations for these metals are probably
normal for Gore Creek and derives from soils and geology of the basin.
However, urban runoff may be an additional contributor particularly in
Che case of lead.
The Eagle Hiver water quality problems near Gilman and upstream are
principally due to occasionally high concentrations of lead, mercury,
iron and manganese. These concentrations are due in part to natural
background sources, but are apparently increased by mining activities at
Climax on the East Pork Zagle River. The one recorded instance of
bacterial criteria violation on the Sagle liver or its tributaries up-
stream of the study area was on Turkey Creek upstream of Che Bed Cliff
water intake. Tbe violation occurred during late summer low stream flow
and probably represents the effects of nearby stock gTaaiag. The viola-
tions of criceria for iron, cadmium and manganese in Cross Creek above
Bacde Mountain School and upscream from Che New Jersey Zinc tailings
pond cannot be dismissed as natural background. Concentrations of iron
and aanganese are highest during low flow in Cross Creek and lowest
during high flow. Iastream concentrations appear to be influenced by a
relatively constant inflow. Data from Reference 4 indicates the water
in the Sew Jersey Zinc tailings pond has very high concentrations of
iron and manganese. Seepage from these ponds or some other activiey
associated with the mining operations is the likely source. The tail-
ings pond data indicate very low concentrations of cadmium. Levels of
cadmium were 5 g/1 which exceeds water quality criceria, buc does not
appear to be high enough for seepage to materially affect Cross Creek
wacer quality. Cadmium levels in Cross Creek are therefore more likely
a result of background contributions.
The major water quality problems in the Eagle River from the New
Jersey Zinc mining area to the Gore Creek, and in Cross Creek below
Battle Mountain School are caused by discharges and seepage of metals
and chemicals from the tailings ponds. This conclusion has been veil
documented by other investigations. See References 1, 2 and 3. These
parts of the streams also exhibit high bacterial counts which exceed
criteria. There is no clear explanation for these observances. The Red
Cliff sewage collection and treatment system does not operate properly
12
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and frequently discharges dilu.ce raw 3ewage co che Eagle River. This
syscem may be a possible source. Most of che high bacterial counts
occurred during low flow periods in. ehe Eagle River which suggests a
point source discharge is the main contributor. However, che highest
bacterial count was for fecal streptococci, 365 KPN/LOO si, aad occurred
during spring snowmelt runoff.
the seasonal variations and general Increase in pollucant levels in
3«aver Creek froa upstream to dovsstreaa suggest chat che alkalinity,
hardness and total dissolved solids concentrations are caused by che
erosion of exposed evaporite formations within che lower Seaver Creek,
drainage basin.
Ihe water quality in the Eagle River below Gore Creek reflects che
effects of the upstream water quality problems Just discussed. Metals
concentrations are reduced by che dilution afforded by flow3 from Gore
Creek., but 3till exceed criteria. Suspended sediment in Gore Creek
increases the levels in che Eagle River. Ammonia levels appear equally
influenced by Gore Creek and upstream Eagle River concentrations as are
levels of tocal dissolved solids. Bacterial councs appear to be in-
fluenced primarily by levels upstream in the EagleRiver and other con-
tributions Co the Eagle Stiver below Gore Creek.
XraCFf CONDITIONS
The large aajoricy of previous investigations were concerned with
normal flow conditions and did not address snowmelt or rainfall runoff
conditions. Reference 3 does contain recent (1976) data which were
obtained during spring snowmelt runoff as indicated by high stream
flows. The data are sparse and few clear trends are apparent. Gore
Creek had higher turbidity chan at low flow periods, and the Eagle River
upstream from Cross Creek had Lower concentrations of toxic metals.
Also, the Eagle River below Gore Creek had higher turbidity and levels
of suspended sedinents, but lower concentrations of toxic metals than
during low flow conditions.
13
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SUMMARY
Historic data and water quality assessments perforaed by previous
Investigators support the contention that ooa-poiat sources of poLlution
are significant contributors to che water quality problems of the study
area. Except for the seepage from Che New Jersey Ziac tailings ponds,
the aon-poiat sources are related to snowoelt runoff, rainfall runoff,
or both. One suspected case of seepage from a failed 3epcic system on
the upper reach of Gore Creek was documented; however, much more inten-
sive field investigation of existing or abandoned septic systems la che
study area would b« required to determine if this source of non-point
pollution is coomon. Both natural and aan-induced non-point sources of
pollution exist in the study area. Levels of cadmium and fecal bacteria
appear co be influenced by natural phenomena and conditions. However,
concentrations of lead in Sore Creek cannoc be adequately explained by
natural background. Turbidity and high levels of suspended solids, and
to some extent total dissolved solids, are che result of erosion from
construction areas.
More detailed examinations of conditions in the study area per-
taining to construction site erosion and urban stormvater runoff con-
tributions follow.
14
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SECTION V
SOIL EROSION
The forces of wind and water, sometimes aided by nan, cons candy
work co dislodge, move and redeposic sail. This wearing away of Che
land surface is called erosion and is a oacural continuing process.
A discussion of erosion processes based upon material from References
7, 3 and 9 follows. Most erosion research has been concerned vich rain-
fall and stream erosion processes, and how chey are acceleraced by che
actions of man. Liccle research has been done on snovmelc runoff erosion.
Regardless, che discussion will provide a framework for understanding
what has and is happening in che study area, and what nay happen in
che future.
EROSION PROCESSES
When raindrops hie a soil surface, che impace can decach and splash
soil particles inco che air. On level ground, che particles are gen-
erally distributed uniformly around che point of iapacc, but on slopes
there is a net downslope transport of particles. If rain has been fall-
ing for some time, the soil surface will be vet resulting in some water
seeping into che soil, and che rest running downslope. The film of vacer
running over a soil surface doesn't have enough eaergy co decach soil
particles from che soil oass, but can pick up loose parcicles oa che sur-
face or particles detached by raindrops. This process is called sheec
erosion. The film of vacer flowing over an irregular soil surface divides
or gathers inco rivulets which have enough energy to loosen and detach
soil. Rivulets become larger and cause rill and gulley erosion, and
finally, the flow in storm swollen streams causes stream bank erosion.
The portion of rainfall which seeps inco che ground may trigger mass
soil movements. Soil slopes are stable most of che time because cne fric-
tion and cohesion forces between soil particles are greacer cnan che
15
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forces of gravity. When coo much vacer seeps into soil, friction and
cohesion forces are reduced to the point that gravity causes some of the
soil mass to move downslope. A. very slow movement is called soil creep,
and a fast movement is a landslide. If the amount of water In the soil
Is very high, the soil mass becomes very liquid once movement begins and
mudflovs may result. In any case, these mass movements make the soil
much more susceptible to other erosion processes, or may directly deposit
large quantities of sediment Into flowing streams.
When rain falls on vegetation instead of a bare ground surface, its
erosion force is reduced. Trees, shruos and grasses absorb most of the
energy of falling raindrops, and the root system of vegetation acts as a
reinforcing binder. Other types of ground cover, both natural and arti-
ficial, can be effective in reducing rainfall erosion. Ground cover also
slows Che flow of water over Che ground surface reducing che erosive
forces of overland flow, and promotes the seepage of surface water into
che ground. In some situations, increased water seepage may increase
the chances for mass soil movements, but che consequences are not as
great because a vegetation cover still provides a large measure of pro-
tection from ocher erosion processes.
The cerm suspended sediment refers co che soil particles suspended
in flowing water. It also implies a process chac must occur sooner or
later, tnat being the deposition of soil or sedimentation. It may occur
very near a soil particle's original location, or it may occur hundreds
or thousands of miles away. If che flow velocicy of a scream decreases,
perhaps because che slope ic is flowing over decreases, ic will no longer
have enough curbulent force to keep che larger soil particles in. susoen-
slon and chey will seccle ouc. The flow of wacer may continue co move
these particles along che ground surface, buc not as suspended sediment.
Thus, che cocal amount of sediment transported by a stream consists of
suspended sediment, and material moving along cne scream beo vmch is
called bed load. If a scream's velocity decreased further or flows into
a quiec body of wacer, more if noc all suspended sediaenc will settle ouc.
Some bodies of wacer such as large lakes or reservoirs may have wind or
cemoeracure caused currents vnicn prevent che settling ouc o£ finer
particles. Conversely, a stream's velocity may increase over some dis-
tance of increased channel slope, and the oea load will oe rasuspeaaea.
-------
In any case, che erosion process is one of continual pickup, transport
and deposition.
The erosion processes of melting snow are similar to rainfall after
it has fallen, but does not include the erosive force of impacting rain-
drops. As the surface of the snow cover melts, water percolates through
the snow to the ground surface and flows along che ground. Thick snow
covers insulate the soil mass so that freezing is usually limited to
shallow depths which favors the absorption of thawing water and melting
snow by the soil. The snow melting process is usually slow and the quan-
tity of overland flow is small compared to rainfall runoff. This further
reduces the erosive potential of snowmelt runoff. However, certain cir-
cumstances can cause serious erosion during snowmelt. If in tne fall,
rains have increased che water content of che soil and hard freezes occur
before the first significant snowfall, che frozen soil layer may be deep.
During snowmelt, the water would run off racher than being absorbed caus-
ing greater erosion. Warm spring weacher, 3priag rain, or boch, could
greatly accelerate snovmelc and create strongly erosive overland flows.
When the soil surface is disturbed and the protective vegetative
cover aestroyed, erosion is greatly accelerated because loosened and de-
tached soil particles are exposed co erosive forces. Construction activ-
ities often involve removing che vegecative cover and the topsoil exposing
the subsurface layers. Subsoils generally have a range of particle sizes
larger than surface soils, and often contain no re sand, silc and gravel.
Thus these soils are less cohesive and are more susceptible to erosion.
They also sore readily absorb water and are more susceptible to mass
movement. Thus construction activities, and co a similar extent farming,
destroy the vegetative cover and disrupc che soil resulting in greatly
accelerated erosion and transport of sediment co streams and lakes. When
construction is complete, landscaping or natural revegetation begins co
restore che area and che race of erosion diminishes. In some climates,
cms "healing" process may cake only a few months, in others several years.
There are many formulas for calculating cne amounc of soil erodea
from an area. They are based Largely on resulcs from researcn on sneec
and rill erosion of agricultural lands caused by rainfall. The formula
used in chis scudy was caiten from Reference 10. Ic is given below :o
further demonscrace cne iaoortance of some of che faccors affecting
17
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erosion. The modificacions made Co che equation co make it applicable
co che study area are explained in a later seccioa of this report. The
equation is:
E - 3RPSC
where
2 » Erosion in cons per acre per year
B - Basic erosion race in cons per acre per year
determined from field measurements
R ¦ Erodibilicy coefficienc
P ¦ Precipicacion coefficienc
S ¦ Slope coefficienc
C ¦ Vegetative cover coefficient
The formula states chat an erosion rate is equal co a basic erosion race
modified by various factors. When one or sore of che modification
factors increases, then the erosion race will increase. Figures 1 and 2
show how che coefiiciencs for slope and vegetative cover depend on slope
and vegecacive cover percentages. For example, Figure 1 indicaces chat
if the average slope were 30 percenc, che basic erosion rate would be
aiulciplied by a coefficienc of 15. If che saae slope is covered 50 per-
cent by vegetation, che vegetative cover coefficienc would be 0.067, which
is multiplied times che basic erosion race. The nec effect, in this ex-
amole, of vegetative cover and slope is 15 times 0.067 or 1.00.
An adjustment has been aade in Figure 1, shown by a dotted line, co
account for increases in erosion races above that expected for only stieec
and rill erosion. This adjustment is an upper liaic vfu.cn incorporates
gulley erosion and mass movement effeccs for cue and fill construction
slopes based upon information in References 7, 3 and 11.
Soc all eroded material from a runoff event necessarily ends up in
a scream. As was mentioned earlier, soil particles suspended m runoff
nay be deposited ac intermediate locations along a slope. Thus calcula-
tions of che amount of sediment coming from a particular drainage area
muse account for cnis efface by modifying che erosion race oy a sedimenc
celivery ratio. The result is called cue seaimenc yield. Reference 7
gives a number of equacions and graohs relating cr.e sediment delivery
racio princisally co che size of cne drainage area. Figure 3 from this
18
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FIGURE 1. CHANGE IN SLOPE COEFFICIENT
WITH CHANGE IN SLOPE PERCENTAGE
40
_ 30
£ 20
u
ia i
! ' ~1U
X
C "3
err:
\iTZ
~C - "
3 ! I:
C -
1 b Z .
1 • 1
-<
w ^ 1
;
JSLDFE^a OfJiiliTC
F tfiBR£^=CtfigBaStbV£S£f£EHECOVEEEeOEFnUENT
—y^H-CHANGE-IN-VEGETAm^-COVER-PERCENTAGE--
30
SO
1 00
0
20
VEGETATIVE COVER, percantage
-------
FIGURE 4. WEEKLY WATER AND SEDIMENT DISCHARGE
DURING SPRING RUNOFF IN GORE VALLEY
6 000
a ooo
4 000
2.000
11 II 1 1 1 1 III
PIA1 - 1 45S TONS
A-
1 1 1
-
..
i i i—i—i i r i i—r~r
r\
I I I I I t I
i i i I—i i i—r-1—r
——» stomtHi
aoo
BOO
400
2 000
1.200
0 000
I 000
• 000
a ooo
4 000
2.000
hH
b/4 5/18
a/151 a-23
5/29 6/12
7/10 7/24
4/20
5/l?|V3l I 6/14 I 6/201 7/12 1 7/20
4/27 5/11 5/25 0/8 8/22 7/8 5/10 5/24 8/7 8/21 7/5 7/19 8/2 5/B 5/22 6/5 8/19 7/3 7/17
WEEKS ENDING WEEKS ENDING WEENS ENDING
1974 1975 1976
-------
reference is an example of a graph of chis relationship. This graph and
other available data and equations are based on information for rainfall
erosion in non-mountainous areas. The equations which include the effect
of slope on the delivery ratio indicate chat the delivery ratios for
streams of the study area tributary to the Eagle River vary between 0.6
and 1.0. In other words, 60 to 100 percent of eroded material is trans-
ported out of a drainage area by its streams. Sediment delivery ratios
for the study area drainage basins are probably closer to 100 percent
than 60 percent because the slopes of the terrain are high, and because
the sustained overland flow during snowmelt promotes the transport of
sediment once it is suspended.
Background information oa erosion processes has been presented,
and how it relates to the study area conditions has been generally dis-
cussed. The application of this information to the study area experience
is next.
STUDY AREA EXPEDIENCE
Large increases in suspended sediments were observed in 31ack Gore
and Gore Creeks shortly after the construction of Interstate Route 70
began in Vail pass. Subsequently, U.S. Geological Survey stream flow
and sediment monitoring stations were established on Black Gore and Gore
Creeks. Their locations are shown on Plate 1. The data from these
stations are summarized in Figure 4 and Tables 2 and 3. See also Plate 3.
About 80 percent of annual erosion occurs during snowmelt in late spring,
and is the reason why only this period is shown in Figure 4 for the tnree
water years. Annual yields of water and sediment are given in Table 2,
and the drainage area for the two monitoring stations is given in Table
3. The Black Gore Creek basin is a subbasin of the Gore Creek basin and
is about 36 percent of its area. Also, the Gore Creek station is
4.2 miles downstream of the 31ack Gore Creek station.
21
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TABLE 2. Gore Valley Annual Water and Sediment Yields
1
Monitoring Locations
Wacer Year
(12 nonths ending
September 30)
Gore Creek
at Vail
Black Gore Creek
Water
Acre-feet
Sediment
Tons
Wacer
Acre-feet
Sediment
Tons
1974
76,869
3,586
24,624
4,697
1975
72,289
2,661
19..423
1,711
1976
54,160
1,151
15,952
664
Source: U.S. Geological Survey Wacer Resource Reports for Colorado.
TABLE 3. Gore Valley Drainage Basin Areas
Monitoring
Location
Area Drained
Acres
Sauare Miles
Black Gore
Gore at Vail
12,160
35,200
19.6
55.0
23
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There are several general observations worth remarking on before
beginning a detailed examination of the data. Both the peak weekly and
annual discharges of sediment from Black Gore Creek into Gore Creek de-
creased drastically year to year after 1974. A decreasing trend can
also be noted for the amount of water discharged; however, not enough
to fully explain the decrease in sediment discharge. The peaks in
weekly sediment discharge from Black Gore Creek correlate well 'with
several peaks in the records for Gore Creek clearly showing the impact
of erosion in the Black Gore Creek basin on Gore Creek. This impact
was magnified in 1974 because the peak water and sediment discharges in
both Gore Creek and Black Gore Creek all occurred at the same time. In
later years, the peak sediment discharge in Gore Creek occurred two-
to-four weeks after peaks for Black Gore Creek. Black Gore Creek dis-
charged a total of 4,697 tons of suspended sediment to Gore Creek in
1974. However, 4.2 miles downstream at the Gore Creek station, only
3,586 tons were discharged. Where did more than 1,100 tons of sediment
go? The monitoring stations measured only suspended sediment. Since
the stream bed slopes decrease by a factor of more than four near, but
downstream from the Black Gore Creek station, the reduced water velocity
would allow sediment to settle out. Thereafter, sediment would be trans-
ported as bed load, and not be detected at the Gore Creek monitoring
station. Moving from the general to the specific, the data will next
be analyzed to determine estimates of normal and accelerated sediment
yields, erosion control effectiveness, and times to recovery.
Certain data indicate that the normal sediment yield for the Gore
Valley is probably very low, that is, considerably less than 1.0 tons per
acre per year. See Plate 3. Reference 12 presents data obtained from
the Fraser Experimental Forest indicating an annual sediment yield of
from 0.001 - 0.0215 tons per acre. The vegetative cover and average
slopes of the basins studied are very similar to those of Gore Valley.
However, the highest measured sediment yield, 0.0215 tons per acre,
is from a watershed where about one-half the timber was logged over a
two year period two years before tne eight years of records used to
calculate the sediment yield. A direct estimate of normal sediment
yield can be determined from data in Tables 2 and 3. Figure 4 indi-
cates that 1976 was a more normal year than previous years although
24
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still affeccad by erosion from construction sites. By subtracing the
Black Gore Creek sediment discharge in 1976 from that measured at Gore
Creek, the amount of sediment discharged by remainder of the Gore 3asin
can be determined. Thus 487 cons were discharged from 23,040 acres or
0.0211 tons per acre, which is consistent with other reported data. A
value of 0.02 tons per acre per year for the normal sediment yield m
Gore Valley will be used.
The equation for determining sediment yield is the same as the
equation for erosion with a modification accounting for the sediment
delivery ratio. This equation is:
Y » (D)(E) = (D)(BRPSC)
where :
Y = sediment yield in tons per acre per year
D ° sediment delivery ratio
B, R, P, S, C. = as previously defined
The sediment delivery ratio will be assumed to be 1.0, or very nearly
so, such that the erosion rate and sediment yield are essentially similar.
This assumption is largely justified on the basis that che primary ob-
jective is to be able to predict sediment yields from construction sites,
and these sices are going to be located fairly close to streams. The
erodibility coefficient is dependent on soil characteristics, and
Reference 3 indicates that a coefficient of 0.34 is appropriate. The
average slope in the Gore Valley is about 25 percent, and from Figure 1,
the slope coefficient is 13.3. Ic is estimated that 90 percent of the
area is covered by vegetation or equivalent cover, therefore, the vege-
tative cover coefficient is 0.01. There is no direct data which can
be used to estimate che value of che precipitation coefficient. How-
ever, since ic is che only unknown in che sediment yield equation, tne
equation can be used to determine its value. The value of P, the pre-
cipitation coefficient, determined in this way is 22. References 7 and
S indicate chat che value of this coefficient for rainfall is 50 or
somewhat less. Reference 13 indicates chat snowmelt is 40 percent as
25
-------
efficient as rainfall in producing erosion. Thus a precipitation co-
efficient for snow would be on the order of 20 or less. The value of
22 determined above appears reasonable particularly considering most
but not all annual precipitation is in the form of snow.
A. general prediction equation can now be developed for the Gore
Vallejr by combining constants and incorporating a coefficient, A, for
accelerated erosion. This equation, which predicts sediment yield, in
tons per acre per year, is:
y = 0.15 SCA
The values for S and C are given in Figures 1 and 2. The value of A is
1.0 for undisturbed land areas.
The normal sediment yields predicted by the equation vary from
0.002 tons per acre per year for a five percent slope with 100 percent
cover, to 0.114 tons per acre for a 40 percent slope with 60 percent
cover. The similarities in terrain, soils, and weather indicate that
this equation is applicable to other portions of the study area as well
as to the Gore Valley.
Actual construction site sediment yields, the effectiveness of
erosion control measures, and recovery times can also be estimated from
the Black Gore Creek sediment data together with information on the con-
struction schedules for 1-70 from Reference 14. Heavy construction be-
gan in the Vail Pass area of the 31ack Gore Creek watershed in early
spring of 1974. Estimates of area disturbed during the 1974, 1975, and
1976 construction seasons were developed from the plans and bid schedules
of Reference 14. The results of these calculations are given in Table 4.
TA3LE 4. Sediment Yield Rates from 1-70
Construction Sites
Sediment Yield Rate Factor Increase Estimated Time
Water Year tons/acre/yr in Sediment Yield to Recovery, Years
1974 60 3,000 5-6
1975 14 700 4-5
1976 4 200 3-4
26
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The factor increase in sediment yield for 1974 is higher than the
2,000-2,500 expected. This is probably because there was considerable
earth moving by construction equipment prior to and during peak snowmelt, and
because of extensive gulley erosion of cut and fill slopes. Sediment
yields decreased substantially during subsequent years as erosion control
measures were installed which both reduced initial erosion rates and pro-
moted the recovery of disturbed areas. The estimated recovery times are
based on the assumptions that installed erosion control systems will be
maintained and residual problems will be corrected. It is projected that
by the end of 1981, when the area should be more or less recovered, about
6,600 tons of sediment more than the normal 2,000 tons expected will have
been discharged from the Black Gore Creek basin from 1974 to 1981. 1976
is the first year that a complete erosion control plan was in full force.
Compared to the sediment yield during 1974, erosion control measures were
effective in reducing sediment yields by about 93 percent. This is with-
in the 90 to 95 percent range expected from Reference 15 information. If
erosion control had been as effective from the onset of construction,
about 1,000 tons more than normal would have been discharged during the
eight years.
An accelerated erosion coefficient of 15 is inferred frotn the data.
However, it should be applicable only to highway and road construction
where long cut and fill slopes are characteristic. For construction
characteristic of urban development, a coefficient of 10 should be usea.
The following section of this report will summarize the information
so far developed and illustrate how estimates of sediment yield may be
obtained.
PREDICTING SOIL EROSION
There are three basic equations to be used to predict sediment yield
in the study area. These equations are:
Condition Equation
Natural
y °
0.15
SC
(1)
Road construction
y =
2.25
sc
(2)
Site construction
y =
1.5
SC
(3)
27
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These equations incorporate all che constants and coefficients previously
derived excepc the slope and cover coefficients wnich must be determined
from Figures 1 and 2. An example of how these equations are used follows.
A project is proposed for a four-acre site with an average slope
of 15 percent. Construction of the access road and site preparation for
structures and parking areas are scheduled to begin in April. Road and
parking area paving are scheduled for August after underground utilities
are in place and when the need for heavy construction equipment traffic
is over. The main building envelopes for all units are to be completed
by September and 30 percent of the units finished and ready for use.
The remaining project work would be completed the following year.
Review of project plans indicates that, of the total four acres,
0.3 acres will be cut and fill slopes of 50 percent slope resulting from
access road construction, and an additional 1.2 acres will be disturbed
during site preparation for structures and parking areas.
The current sediment yield from the site is determined from equa-
tion 1 for 15 percent slope and 90 percent cover.
y = 0.15 sc
= (0.15)(8.5)(0.01) (4)
° C0TJS Per 7®ar
The sediment yield the first year will be che tocal from undisturbed
areas, road construction areas, and site preparation areas. The calcula-
tion is summarized in Table 5. The results indicate that the increased
sediment yield would amount to nearly 32 tons the first year. In the
second year, only the roadway cut and fill slopes will contribute as the
remaining disturbed area has been paved, landscaped and sodded or built
upon. Therefore, with an 85 percent annual recovery race, the roadway
slopes will yield (0.15)(17.09) or 2.56 tons, and the total sice will
yield abouc 2.6 cons.
Assuming an erosion control plan fully implemented would reduce che
seaiment yield 90 percent, che yield for che first year would be 3.2
tons, and for the second 0.3 cons.
28
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TABLE 5. Example Sediment'Yield Calculation
Area
Condition
Equation
Constant
(1)
Area,
Acres
(2)
Slope,
%
(3)
Slope
Coef.
(4)
Cover,
2
(5)
Cover
coef.
(6)
Sediment
yield, tons
columns
(1) (2) (4) (6)
Natural
0.15
2.5
15
8.5
90
0.01
0.03
Road
2.25
0.3
50
26
0
0.974
17.09
Site
1.5
1.2
15
8.5
0
0.974
14.90
Total 32.02
29
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SECTION VI
URMiN RUNOFF
Pollutants contained in urban runoff can cause serious water quality
problems in lakes and streams, but the problem has been the subject of
comprehensive research for only about seven years. Organic and inorganic
substances and disease-causing organisms are found m runoff waters, and
most but not all of these pollutants are made or manufactured by man
himself. They are part of his urban inheritance. In sufficient concen-
tration, these pollutants threaten aquatic and wildlife, and man's health
and welfare. Experiments conducted in eight U.S. cities in 1971 provided
comprehensive data which quantified the amount and type of pollutants on
city streets. Nearly a ton of material per mile of street was found on
the average. See Reference 16. These results stimulated many questions
about the sources for this material, its accumulation on streets, and the
processes resulting in deposition in screams and lakes. Not all these
questions have been answered satisfactorily, and pernaps never will. But
much has been learned. The remainder of this section will discuss what
is known about urban runoff wacer quality both generally and in the study
area specifically.
PROCESSES
Materials accumulate on the land surface of urban areas in a number
of ways. Part of what accumulates settles out from the air. Dust and
many air pollutants which are not gases are examples of atmospheric
fallout. Many times, these fine particles are resuspended by wind and
air currents only to be deposited elsewhere. Litter is an important
contributor to the urban pollutant load, as are pets, vegetation, and
accidental or intentional spills of materials ana wastes. Sometimes man
places materials on surfaces for good reasons, but they end up adding
to the pollution load. Sand and chemicals spread on icy streets are ex-
amples. The automobile itself is considered a prime source of surface
30
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pollutants. Soot and chemicals, such as lead, in the form of small par-
ticles are emitted from exhausts. Tires which contain small amounts of
metal and other inorganic compounds wear on road surfaces creating fine
debris; and the drippings of oil, grease, brake, transmission and cooling
fluids all contribute to the pollutant load. In short, there are many
sources for the materials deposited on the urban landscape.
Surface pollutants which may be washed off by storm water accumulate
at a decreasing rate until some maximum pollutant load is reached. Much
of the research on pollutant rates is for accumulation on impervious
surfaces such as streets, parking lots, sidewalks, and roofs. Figure 5
from Reference 16 illustrates how pollutants accumulate on the streets of
various types of land use areas. The data used to construct the curves
in Figure 5 are scattered and the curves only show general trends. There
is also general dispute over whether there are real differences between
the pollutant loads for different land uses. See References 17 and 18.
There probably are differences in loadings for different pollutants and
land uses. The information now available is probably inconclusive be-
cause it doesn't give sufficient weight to the differences in climate
among the areas where data were obtained, and the categories of land use
are too general to adequately describe the range, type and magnitude of
human activities they represent. In any event, the general trend of
pollutant buildup with time as shown in Figure 5 appears valid.
The first few days after a storm has washed accumulated pollutants
away, a new pollutant load is accumulating at a fairly rapid rate. As
the pollutant load accumulates, the rate of accumulation decreases as the
total pollutant load approaches some upper limit. Why should there be
an upper limit to the amount of pollutants accumulating on impervious
surfaces? The currently accepted explanation is based upon the under-
standing that vehicles and traffic are a major source of pollutants and
a cause of ground level air turbulence which picks up street pollutants,
whatever their source, and redistributes them elsewhere. Nearly one-
half of the pollutant meterials are particles less than 100 microns in
diameter. However, the rate at which these processes remove material
depends on the amount of material present. Thus, with a relatively con-
stant rate of deposition, the rate of removal increases as the pollutant
materials accumulate day by day until the rate of removal is nearly the
31
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FIGURE 5. SOLIDS ACCUMULATION FOR DIFFERENT
LAND USE AS A FUNCTION OF TIME
35
1100
6
1200
1000
o
o
800
800
o
200
ELAPSED TIME SINCE LAST CLEANING 8T SWEEPING OR RAIN, days
-------
same as che race of deposition. The nee result Is that after a tew weeks,
the accumulacad pollutant load remains nearly constant. Perhaps more im-
portant, within two or three days of pollutant washoff by a rain storm,
about one-half Che cotal pollutant load has already accumulated.
Ranges of loading rates for various pollutants for predominantly
residential areas are given in Table 6. For comparison, loadings rates
used in other studies for Colorado locations are also given. See
References 19 through 21. The ratio of the upper limit to the lower
limit of the ranges varies from two for cotal nitrogen to 60 for sus-
pended solids. These variabilities are an indication of the difficulty
of predicting urban runoff water quality.
Most of the research on pollutant washoff has been concerned vitn
che effects of rainfall, and indicates that the percentage of pollutants
removed depends mostly on total flow from an area. See References 8 and
16. The equation for determining the percentage of pollutants removed
is given below.
p = ioo ( l- eiCRT )
where:
P a Percentage of pollutants removed
K = A constant
R = Runoff rate in inches per acre per hour
T B Duration of runoff in hours
A graph of this equation for low runoff rates is given in Figure 6. The
value of K used in making this graph was 4.6, a well accepted value for
runoff from impervious surfaces. However, predictions of pollution con-
centrations using only runoff from impervious surfaces may be in error
because they do not include che additional dilution from pervious area
runoff. Some research indicates the value of X for an area including
pervious and impervious areas would be significantly less than 4.6, and
may also vary pollutant to pollucant. In any case, snowmelc runoff from
urban areas is dominaced by runoff from impervious surfaces, and a value
of 4.6 for X appears reasonable if somewhac conservacive.
33
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GURE 6. PERCENTAGE OF POLLUTANTS
REMOVED DURING RUNOFF
90*.
755
0 1
0 2
0
0 1
RUNOFF RATE, in /hr
-------
TABLE 6. Loading Races—Ranges of Reported Data, and
Values Used in Colorado for Comparable
Land uses
Constituent
Ranges of
Loading
lbs/ac/day
Aspen
lbs/ac/day
Denver
lb/ac/day
Steamboat
Springs
lb/ac/day
Suspended Solids
0.5 - 3
0.87
300
0.03 - 0.35
0.032
0.35
0.136
COD
0.23 - 0.76
0.23
Total Nitrogen
0.01 - 0.02
0.052
Total Phosphorus
0.002 - 0.01
0.011
Total Lead
0.004 - 0.02
0.0015
The runoff race during snowmelc is very low in the study area and
averages abouc 0.01 inch per hour with peaks of about 0.02 inches per
hour. Assuming chat Che average duracion of snowmelc runoff eacn day
is four Co six hours, Figure 6 indicaces about 20-40 percent of the pol-
lutants would be washed off. However, Figure 5 indicates similar rates
of pollutant accumulation. The implication of this observation is thac
che amounc of pollutants in several days of snowmelt runoff would be
higher than in the same quantity of runoff from a single rain storm.
The concentration of pollutants in urban runoff has been measured m
a number of investigations. Measurements of pollutant concentration and
total pollutant discharged during rain storm runoff events have snown
evidence of a first flush effect. That is, pollutant concentrations are
highest during early runoff and rapidly decrease thereafter, and by the
time the runoff flow rate peaks, the majority of pollutant load chat will
be washed off has already been discharged. The lower runoff rates cnar-
acteristic of snowmelt do not appear co have a strong first flush effect.
Figure 7 shows how the concentration of lead in a storm drain flow varied
during a snowmelt event in Denver m February 1977. The total runoff for
this event was about 0.011 inches per acre with a peak runoff rate of
about 0.004 mcnes per hour. The absence of first-flush efrects are apparent.
35
-------
FIGURE 7. CONCENTRATIONS OF LEAD IN
SNOWMELT RUNOFF IN DENVER, COLORADO
i
N,
•
V
•
\
\
\
>
\
/
/
\
\
v»»
/
•
t
\
LUSH 3EH
* V 1 Of)
0 1 2 3 4 3 3
0URAT1ON OF RUNOFF, hours
-------
The water quality characteristics of urban runoff as reported in
Reference 8 are given in Table 7. Measured water quality in Aspen,
Steamboat Springs, and Upper Eagle Valley is given in Table 8. The run-
off water quality data for the Upper Eagle Valley in Table 8 is a brief
summary of an extensive sampling program. This program and its results
will be discussed in greater detail later in this report. A comparison
of Tables 7 and 8 does not reveal strong differences. Suspended sedi-
ment concentrations are of similar magnitudes but tend to be somewhat
higher for the ski resort areas. Phosphorus and BOD tend to be somewhat
lower, and lead concentrations appear to trend toward higher values in
Table 8.
In general, the processes controlling pollutant buildup and washoff
in the study area are somewhat different than the more generally under-
stood rainfall-runoff processes, but the end result is very similar. That
is, the pollutant concentrations in urban runoff are similar. The
duration of impact on receiving streams during spring snowmelt is probably
much longer and less likely to exhibit the shock loading characteristics
of rainfall runoff. In an attempt to gain a clearer understanding of
snowmelt runoff characteristics and impacts, an extensive sampling pro-
gram was conducted m the study area during March and April of 1978.
This program and its results will be discussed next.
SAMPLING PROGRAM
Information available from other investigations of urban runoff proc-
esses, characteristics, and impacts indicate these factors depend on the
characteristics of the locale of interest. An urban runoff water quality
sampling program was planned and executed to obtain data which would be
specific to the area, and provide a more firm basis for assessing the
significance of non-point source pollution.
Teams of local agency and EPA personnel were organized and trained in
sampling and measurement techniques. The teams were assigned specific
sampling locations, and performed sampling when notified that a runoff
event was beginning. Samples were obtained both in-stream and from run-
off discharges to streams. There were five m-strearn'sampling locations
on Gore Creek; one on Black Gore Creek; and three on the Eagle River
37
-------
TAIll.K 7. Watur QuallLy Characteristics of
Urban Itunoff
Durhjin, NorLli Carolina Cincinnati. Ohio _ Tulsa, Oklahoma MJWA
Rangt; (iiifj/1) Uanne (»>n/l) Kan^e (mn/1) Ra>>ne (n^TYj
Low High Mejn Low IILfili Mean Low High Mean Low High
(Jilt)
_
__
2
84
19
8
18
11.8
1
700
CUD
20
1042
170
20
610
99
42
138
85.5
5
3100
Total solids
194
8620
1440
-
-
-
199
2242
54 5
4 50
14,600
VolaLile biia-
jtuiided i>ul ids
5
970
122
1
290
53
_
_
12
1600
i>u:>|>eiided ^oliJb
27
7J40
1223
5
J 200
210
84
2052
367
2
11,300
I'll
-
-
-
5.3
8.7
7.5
6.
a
6.
k
7.4
_
Total PO4
0.2
16
0.82
0.07
4.3
0.8
0.
54
3.
49
1.15
0.1
125
NO j
-
-
-
0.1
1. 5
0.4
_
_
_
_
_
Chlorides
-
-
-
-
-
-
2
46
11 .5
2
25,000
I'l)
0. L
2.86
0.46
-
-
-
-
--
_
0
1.9
Ca
0.1
Jl
4.8
-
_
_
--
_
_
Cu
0.04
0.50
0. 15
-
_
__
_
_
fe
1.3
58. 7
12
-
-
_
_
_
Mg
4.6
24
10
-
-
_
.
_
M11
0. 12
J. 2
0.67
-
_
_
A Ike
24
124
56
10
210
59
_
Focal conforms
(fl 101) ml)
100
200,000
2J,000
-
-
-
10
18,000
420
55
J 12xl06
Kout'tcij: KeFuruiu'esi 21— 24.
-------
TABLE 8. Urban Kuiiaff UldLer Quality Measurements
In Colorado Mountain ResorLs
ConsiJ Lucent
Aspen
S no wine It
Range, mg/1
Steamboat Springs
Snownielt 0.33 In. Raiu
ing/1 Range, mg/1
Upper Eagle Valley
Snownielt
Range, mg/1 Median, nig/1
Suspended Solids 1,269 - 1,970
ToLal Dissolved Solids 52 - 520
biochemical Oxygen Demand 22 - 125
Chemical Oxygen Demand 365 - 605
Total Nitrogen 2.7 - 4.8
Total Phosphorus
ToLai Lead
2,130
160
39
480 - 3,300
4 - 8.5
16 - 120
0.05 - 0.20
24 - 3,220
98 - 3,630
J - 9
9.91 - 13.85
0.055 - 5.76
0.019 - 2.25
214
346
7
2.62
0. 156
0.16
-------
Seven discharges to Gore Creek, including Che Vail Sewage Treatment Plane dis-
charge, and one Co che Eagle River were sampled. The locations of these sam-
pling ooincs is shown on Plate 4. Samples were collected on March 3, 9, 28,
29, and 30; and on April 27, 1978 and analyzed by EPA laboracories. In some
cases, estimates of flow rates for discharges to streams vera obcamed.
Water quality measurements included temperature, pH, conductivity, dissolved
oxygen, total organic carbon, five-day biochemical oxygen demand, total
suspended solids, total dissolved solids, nitrate plus nitrite, ammonia-
nitrogen, total Kjeldahl nitrogen, total phosphorus, oil and grease, total
lead, and total and fecal coliform counts. The samples taken on April
27 were also analyzed for total cadmium and total selenium. The data
obtained are given in Appendix A of this report, and its significance
is discussed below.
ASSESSMENT
The water quality daca will first be examined for trends in in-stream
water quality and the contributions discharges to the Gore Creek and
Eagle River make to these trends. Next, the quality of runoff discharges
will be examined, again in an effort to disclose trends and significance.
However, there are cwo pieces of information, one regarding stream flow in
March and April, and the other concerning a pollution episode, to be
presented before a discussion of in-stream water quality can proceed.
The sampling program in March and April of 1978 was conducted during
early snowmelt according to preliminary flow data for Gore Creek at Vail.
See Reference 26. About 9 cubic feec per second was flowing m che
Gore Creek at Vail during March 8 and 9 sampling. This corresponds to
winter low flows. In late March, flow was measured as 21, 26, and 36
cubic feet per second on March 28, 29, and 30. Flow on April 27 was 80
cubic feet per second, and a peak flow of 300 to 400 cubic feet per
second was expected in June. Most of the snow in the valley floors had
melted by late May.
A pollution episode occurred during late March which was reflected
in che sampling data and resulted in an outbreak of giardiasis, an
intestinal disease. A sanitary sewer became blocked, and backed up sewage
40
-------
overflowed Into Gore Creek upstream of the Vail water system intake. The
chlorine disinfection system for the water supply was apparently not com-
pletely effective because of high turbidity or suspended solids. The
level of suspended solids in the Creek at chat time ranged from 5.6 to
14 milligrams per litre (mg/1). The water quality data for samples ob-
tained near the water system intake were clearly elevated from values
observed during early March and late April for fecal coliform bacteria,
BOD, and ammonia nitrogen, indicators of sewage pollution. The BOD
data clearly show this effect in Figure A-l, as does the ammonia data in
Figure A-3.
The water quality of Gore Creek and the Eagle River degrades as these
streams flow through the study area. Furthermore, the primary reason for
this degradation is non-point source pollution. This is also likely to
be the case in the future despite improvements in the quality of point
source discharges if no corrective actions are taken. Water quality would
continue to exceed criteria for aquatic life and water supplies. These
conclusions are presented here at the outset to challenge the reader to
examine the data and arrive at his own conclusions. The basic data is
given in Appendix A as are some graphs of selected data. Much data and
several graphs are also included on Plate 4. The following discussion of
in-stream water quality trends will be taken largely from the summary of
data presented in Table 9.
The water quality in Gore Creek above where it is joined by Black
Gore Creek is very good. Aquatic life water quality criteria for pH and
lead content were exceeded each on two occasions, but overall quality is
good.
Black Gore Creek wacer quality reflects the influences of 1-70
construction and operation. Lead and pH criteria were exceeded most of
the time. Compared to Gore Creek headwaters, the levels of total organic
carbon (TOC) on the average in Black Gore Creek were four times higher,
BOD5 levels were 50 percent higher, total suspended solids (TSS) levels
were six times higher, total dissolved solids (IDS) levels were more than
three times higher and nitrate plus nitrite (NO3+NO2) levels were five
times higher. The high lead concentrations, 20 to 300 percent above
standards, are most probably from washoff of pollutants from the highway,
41
-------
TABLE 9. Summary of In-SLreant Water Quality DaLu
Obtained SprLng 1978, Upper Eagle Vailey
Colorudo
U-.Cc, uglily r*ruclcr Cora Uaadoacar,. Black Core Creak, Uora at Eagla tagle *l„r above Eagle »1«, below Eagle liver below
mj\ ....Uaa ullmwlac Station CC-1 Station BGC-2 River. Station CC-14 Hlnturu. fetation ER-11 Mlntura, Station Hl-lJ Cora, Slatlou W-1S
lujlciuej Mlgli Lou Avo. Ulgli Lou Ave High Low Ave. High Lou Avo. digit Low Ava. High Lou Avi
T«-u>pcrulure *C
4
0
J
4
0
1.2
a
0
4.7
6
0
3
4
2
3 4
7
1
3
pU (b.U )
10
).a
a.a
9.5
a.6
9 1
a.7
7 a
tt.2
a.2
7.4
7.6
a.2
7.6
a
a.s
7.9
a 4
DO
10
4
9.7
10.1
10 7
9.9
10 2
11.1
7 4
9.7
10.5
10.1
10.3
10 4
9.4
10
10.7
9 4
10.0
TOC
5
tt
1 J
4.0
25
3 6
1> 9
26
4.0
14.4
a »
4.4
6.9
12
3
a.4
14
6. i
10
HODj
0
/
0.2
0 4
0.8
0.4
0 6
12
2a
4.2
3.a
1.0
1 9
1.6
0,6
0.9
1.5
0.9
1.1
TSS
4
4
0 4
2.4
22
4.6
1) o
100
12
34
27
6.5
16.6
26
7.4
16.4
19
a 4
14.1
TUS
62
41
5*.?
21B
114
179
306
126
222
260
24a
24ft
248
23H
245
2 34
216
224
0.
16
0 0}
o 134
1.11
0.19
0.72
0.7*
0.6
0.65
0 23
0.14
0.19
0.27
0 17
0.23
0.46
0.34
0.41
Hllj-M
0
06
<0 01
<0.01
<0 01
0.14
0.02
0 09*
0.05
0.12
0 04
0.04
0 01
o.oz
0 07
O.03
0 040
UN
0
tt
<0 Qi
<0.04
0.25
<0.02
0.1]
3 0
0 19
1.2
0.46
0 J2
0.37
0.45
0.24
0.32
0 52
O 34
0.43
Tuln1 HIirogett
0
25
<0 Itt
<0.20
I 16
<0.20
0 U6
1.6
1.1
i a
0.69
0.4a
0 57
0.72
0.42
0.44
0.46
0 79
0.44
Tuidl fltobpttoruu
<0.00*
<0 00)
1.0
0.16
u.ia
0.02}
<0.004
0 014
0.47
0,005
0 022
0.103
0 07
0 046
Tuul lend, iiga/L
7
<4
<5
15
<5
tt
14
<5
7
20
10
16.2
47
15
25
IB
10
14
tcial lull. I/1UO bl
<2
<7
170
a
10)*
ia
<2
6
4
<2
<2
19
4
10
't»Lludofl dalo fur March id, 29, and 30.
Source. Rcfoscn^c 24.
-------
and che high NO3+NO2 levels are probably caused by che vashoff of fer-
tilizers. TOC, BOD, TSS, and TDS are consequences of construction.
The water quality of Gore Creek as it enters che Eagle River is
lower by far Chan che high quality of che headwacers- The pH has been
lowered somewhat, but so has the level of dissolved oxygen (DO), and the
ceaperacure is somewhac elevaced. None of chese parameters exceeded
criceria; however, a low DO level of 7.3 ng/1 was measured. The DO
criceria during spawning season is 7.0 mg/1. Average TOC levels ac
Scacion GC-3, Bighorn, were 11.6 mg/1 refleccing che merging of Black
Gore and Upper Gore Creeks. However, levels ac che Eagle River were
25 percent higher. Average BOD levels immediacely upscream of che Vail
STP were 1.16 mg/1, a faccor of cwo higher chan ac Bighorn, buc were
2.55 mg/1 immediacely downstream of che Vail ST? discharge. However,
BOD levels increased by anocher faccor of two by che time che Eagle
River was reached. See Figure A-l. The total increase in 30D levels
from Bighorn co che Eagle River was by a factor of abouc 8.5. If che
Vail STP discharge were eliminated, the increase would have been by a
factor of nearly four. Thus che concribucion from the Vail STP is sig-
nificant, buc che large majority of BOD added Co Gore Creek appears to
come from non-point sources. An identical analysis of data for NO2+NO3,
ammonia, TKN, pnosphorus, and fecal coliforms (rC), excluding ammonia and
FC data for late March, leads to the same conclusion except for ammonia
and in some instances NO2+NO3 where during low flow conditions, contribu-
tions from the STP appear to dominate. See also Figures A-2, A-3, and
A-4 in the appendix.
Concentrations of lead in che downstream portions of Gore Creek are
generally higher than in the headwaters. Figure A-5 shows a generally
Increasing trend, but more importantly indicates a number of peaks and
valleys. The peaks appear to reflect non-point source discharges, and
the valleys may indicate that the lead concentrations are for undissolved
lead which is settling out.
Total suspended and dissolved solids levels both increase as the
Creek flows through the Gore Valley. These trends are also apparent in
the grapns of Plate 4, and in Figures A-5 and A-7."' The TSS data for
early March low flow conditions suggest chat significant contributions are
43
-------
made by Black Core Creek, che '/ail ST?, and runoff from che vest Vail area.
The STP contribution in lace Marcn is of much lass imDortance. The hign
suspended sediment levels of April 2 7 appear relaced Co che increase flow
in Gore Creek. Although the upstream concentrations ao not cnange dras-
tically, downstream concentrations are higher by factors of from four to
ten. The dramatic rise between stations GC-3 and GC-6 is probably the
resuspension of bed load deposits caused by increased flow with sedimen-
tation again occurring between stations GC-6 and GC-12. The TDS data
indicate substantial increases in average concentrations, but Figure A-7
indicates the amount of increase is strongly related to flow. In early
March, concentrations increased by a factor of five but by late April,
concentrations increased by a factor of 3. Increased flows in Gore Creek
dilute concentrations of TDS, but the quantity of TDS still increases.
For example, about 160 lb/sec flowed by station GC-14 on March 9, and
although the concentration had decreased by a factor of 2.2 by April 27,
a total of 630 lbs/sec was carried by the stream.
The water quality of the Eagle River also changes as it flows
through the study area. Vater temperatures were similar to those found
m Gore CreeK, and the pH is generally lower but increases slightly
through che study area. DO levels are also corapanble, buc che range
becween high and low extremes was less than in Gore Creek. The levels of
BOD, TSS, TDS, and lead are all lower m the Eagle River below Gore Creek
tnan upstream levels; however, 30D concentrations appear to reflect
contributions from Gore Creek. The decreases in TSS ana TDS levels are
small, about 5 percent, but the trend is consistent. Upstream lead
concentrations are very high and on one occasion approached the water
supply criterion of 50 ygm/1. There is a substantial drop in lead con-
centrations downstream of Gore Creek and probably reflects the dilution
by Gore Creek waters. However, concentrations were still more chan three
times che criterion for aquatic life. Similar affects and trends are to
be expected for other metals such as iron, manganese, and zinc.
The remaining constituents listed in Table 9 all increase in concen-
tration as the Eagle River flows through the area. However, ammonia,
TXM, total nitrogen and fecal colifonns all decrease prior to Gore Creek,
and thereafter are higner tnan in the upstream Dart of che Eagle River.
44
-------
However, Gore Creek flows, as in Che case of lead, dilute coneentrations
of metals and chemicals associated with mining near Cross Creek.
Snovmelt runoff samples were obtained from culverts discharging to
streams. Data were available on the land uses in the drainage area of
some of these culverts and is shown in Table 10. The areas represent the
urbanized portion of the Town of Vail. The low flows from the culverts
and high concentrations of pollutants in the discharges indicate rela-
tively high pollutant loads on impervious surfaces. Attempts to calcu-
late surface loadings are fruitless because of insufficient data on
changes in flow and concentration with time. Apparently reasonable assump-
tions were made for sampling point CU-8 for >iarch 8, and the results
for total nitrogen and BOD loadings were in reasonable agre_aent *ith
data reported for Steamboat Springs in Table 6. However, the result
for total phosphorus loading was over 50 percent higher and for suspended
solids was higher by a factor of four. The same assumptions concerning
the variation of runoff characteristics with time were made for sampling
point CTJ-7NE on March 3. Results indicated that total nitrogen loadings
TABLE 10. Land Use Distribution of Runoff
Sampling Point Tributary Areas
Sampling Points
7ME 71IW 7SE
7SU
8
9
10
Suburban (1-4 D.U./ac), acres
0
0
0.3
0
0.3
0
0
Urban (>8 D.U./ac.), acres
3.2
3.0
1.3
2.3
1.5
1.4
10.9
Commercial, acres
1.1
1.6
1.9
2.3
2.8
3.8
4.8
Open Space, acres
0.5
0.7
1.8
0.2
0.2
0
1.6
Total Acres
4,3
5.2
5.2
4.3
4.8
5.2
17.3
Percent Impervious, %
45
48
48
65
87
67
30
45
-------
were four cimes higher Chan for sampling pome CU-8 and Steamboat Springs,
and the phosphorus loading results were seven times lower than for Sceam-
boad Springs. These exercises do indicate chac che Loading for suspended
and dissolved solids are probably very high with loading rates of from
5 Co 60 lbs/acre of impervious surfaces. These high loading races are
probably the resulc of applying 392 cons of volcanic ash and enree cons
of sales to Vail streets during the winter of 1977-1978. Deicing chemicals
applied by private owners further add Co che load. The impact on water
quality in Gore Creek is discernable in che data plotted in Figures A-6
and A-7.
The pollucanc levels in culvert discharges have a number of trends
related to the sampling periods of early or late March or late April.
The trend for TDS concentrations is che clearest example wherein the peak
concentrations for all the culvert discharge samples were found in che
early March samples. Levels in samples from lace March and April were
progressively lower. The daca for suspended solids behaves in an iden-
tical manner. Peak levels of ammonia tend Co occur in late March or
April data, as is the case for nitrates plus nitrites data. Maximum 30D,
tocal nitrogen, and TOC levels cend to occur m either lace April or
early March daca. Concentrations of oil and grease are highest in early
March, and so are che concencracions of lead co a large extent chough
a few peak concencracions occurred in lace March or April. So clear
crends are apparent in the data for che remaining water quality param-
eters. These trends strongly suggest chac roadways and parking areas are
the major contributors of pollutants in the early snowmelt season, and
that most of chese pollucants are dissolved or very fine particles.
Later in che season, soluble pollucants from pervious areas, and washoff
of litter, garbage, and wastes from sidewalks, commercial areas, and
parking areas probably become more significant.
Samples from culvercs taken m early and late March had snown high
concentrations of tocal lead. Concencracions of total lead Lnclude boch
dissolved and undissolved lead, but runoff data during snowmelc in Denver
indicate that virtually all che lead is undissolved. See Reference 13.
Thus samples chac were obtained from Gore Creek may be misleading because
some lead particles may Mve settled ouc or may be transported as bed
load. The daca from in-scream samples snow lowesc concencracions during
46
-------
early March and highesc concentrations during Late April. The concentra-
tions of tocal lead in the Vail ST? discharge have an identical trend,
and concentrations are very similar to values for Gore Creek. This is
an indication that lead concentrations are high m the Vail water system,
but still within drinking water standards. The high concentrations of
lead in runoff samples prompted the analysis of April samples for cadmium
and selenium. The criteria for selenium are 10 yg/1 for water supplies,
20 Ugm/1 for agricultural waters, and 50 ygm/l for aquatic life. All
samples contained less than 10 ygm/1 of total selenium. The criteria
for cadmium are 10 ygm/l for water supplies and agricultural waters, and
0.4 ugm/1 for aquatic life. The sample obtained from Gore Creek at
station GC-3 contained 14 ugm/1 total cadmium which exceeds all criteria.
Two other in-stream samples exceeded the aquatic life criteria as did all
samples from runoff. The similarities in the concentrations in runoff
and in-stream samples indicates that cadmium is a background constituent.
Average daily pollutant loads for the Gore Valley watershed were
estimated using an annual mass balance approach. Data obtained during
the Spring of 1978 on instream quality and stream flows combined with
historic trend data were used to estimate the annual quantity of various
pollutants discharged. It was assumed that the quantity of a pollutant
discharged was simply the sum of the products of the loading rates for
each type of land use times the area of each land use. The pollutant
loads thus determined are more properly pollutant yields for various
land uses; however, this approach is adequate for a first order estimate.
The results are given in Table 11. A comparison of estimated urban and
suburban pollutant loads with data on Table 6 indicates that loads
for total nitrogen and total phosphorus are higher than anticipated,
while estimated loads for other pollutants appear consistent.
In summary, snowmelt runoff has an adverse impact on stream water
quality in the Gore Valley which is greater than point discharges. The
Vail ST? is an important source of ammonia and bacteria; however, its
contribution of other pollutants is important only during the winter low
47
-------
TABLE 11. Estimated 1978 Average Daily Pollutant
Loads-Gore Valley, lbs/ac/day
Suspended
Land Use Sediments
Total
Dissolved
Solids
BOD
Total
Phosphorus
Total
Nitrogen
Total
Lead
Highway construction 5.3
45
0.12
0.003
0.055
0.005
Urban construction 6.4
45
0.12
0.003
0.55
0.005
Suburban 3.0
12
0.30
0.03
0.35
0.0035
Urban 3.0
20
0.35
0.03
0.45
0.004
Range 0.11
1.0
0.006
0.006
0.009
0.00013
Forest 0.11
0.75
0.003
0.0008
0.003
0.00013
flow period until the onset of snowmelt. The major non-point source con-
tributions m early 1978 in the Gore Valley were the construction areas
in the Black Gore Creek basin and West Vail, and urban runoff from the
Town of Vail. The Eagle River is adversely impacted by contributions
from the New Jersey zinc tailings ponds which contribute metals and chem-
icals. These pollutants are diluted by Gore Creek flows; however, organic
and nutrient materials m Gore Creek elevate the concentrations of these
constituents in the Eagle River. The major conclusion is that withouc
non-pome source control, water quality criteria for aquatic life and
water supplies are not likely to be met in the UDper Eagle Valley.
48
-------
SECTION VII
NONPOIOT SOURCE CONTROL
The previous section of this report concluded that without aoapoint
source controls for soil erosion, urban runo£f, and mining activities,
water quality criteria for aquatic life and water supplies are not
likely to be met in the Upper Eagle Valley. The question is, "what
nonpoint source control practices are appropriate for the study area?"
Thi3 section of the report will present some answers to that question
by first examining the policies of the NVCCOG Areawide Water Quality
Management Plan (NVCCOG Plan), then reviewing the ordnances and regula-
tions of the local agencies controlling land use, then reviewing
practices recommended or implemented in other areas of the United
States and finally by recommending specific practices and programs
which appear most appropriate for the Upper Eagle Valley.
The following discussion is divided into two parts successively
addressing nonpoint sources from construction activities and urban run-
off. Further, each part of the discussion i3 divided into the four
major types of control strategies which are explained below.
Limit the Generation of Pollutants — if the amount of pollutants
generated can be reduced or controlled, then less will be carried
off by runoff.
Limit the Entry of Pollutants into Runoff ~ once pollutants are
generated, there are ways to control their becoming mixed into
runoff.
Limit Entry of Polluted Runoff into Streams — polluted runoff
can be controlled, treated, or diverted so that it doesn't
pollute streams.
a Preserve Streams —~ even if polluted runoff enters a stream,
there are ways by which the effects can be minimized.
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No one policy, strategy, or management practice is concerned vith
only one part of the problem, because many parts are interrelated.
However, the approach described above should provide several poiat3 of
view which together will provide a good overview.
POLLUTANTS FROM CONSTRUCTION
The NWCCOG Plan has two policies which deal directly with the
problem of pollution generated by construction activities. See Ref-
erence 2. These are:
Policy 5 - The surface and ground waters of the region shall be
protected by maintaining permanent vegetative cover and
by controlling disturbances to vegetation.
Policy 6 - The surface and ground waters of the region shall be
protected from all land use and development activities
involving soil disturbance and earth movement which
would cause significant degradation of water quality or
would impair currently designated uses of the region's
water.
Among the practices recommended under Policy 5 - Vegetation, are
two which limit the generation of pollutants. One recommended practice
is to avoid disturbing or removing vegetation just before or during the
winter season. This is because disturbed areas, unless artificially
stabilized or protected, would have little protection from erosive
forces during spring snowoelt. Stabilization of disturbed areas, using
procedures developed by the U.S. Forest Service, the Colorado Forest
Service, and the U.S. Soil Conservation Service, is another recocnnended
practice. The most direct method of reducing the generation of pollu-
tants, limiting the area disturbed in sensitive areas, is also recom-
mended. Sensitive areas are, in this sicuation, areas of easily
erodible soils or areas with moderate to steep slopes, or both.
Two approaches to limiting the generation of pollutants are recom-
mended under Policy 6 - Soil Disturbance and Zarth Movement. The first
approach recommended is to require erosion control plans cor areas with
significant erosion potential by reason of soil or slope conditions or
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Che amount of area disturbed. This approach does noc direcdy influ-
ence che generation of pollutants, but rather indirectly encourages
good planning as a way of avoiding the costs of erosion control. Sug-
gested techniques which can be used to control the generation, pickup,
transmittal of pollutants are given. The second approach recommended
is to limit the heights of cuts and fills on moderate to steeply slop-
ing lands. However, it is also recommended that such restrictions not
be established until experience is obtained in using this form of con-
trol on development activities. No suggestions are made as to how to
get this experience.
The Town of Vail zoning ordnance specifies the percent of a lot
which may be covered by building(s). See Reference 27. This limitation
varies from 20 percent for single family residential zones to 55 percent
for high density residential zones. If a portion of the lot has a slope
of 40 percent or sore, the percentage limitation drops to 15 percent for
low density residential zones. The allowable building coverage for pub-
lic accommodations (hotels and motels) is 55 percent, but coverage up to
80 percent is permissible for core commercial areas, and there is appar-
ently no adjustment for areas of moderate to steep slopes. Residential
areas are also allowed 10 percent for driveways and parking. Separate
restrictions on minimum lot sizes and gross floor area of buildings per
100 square feet of buildable area are given. Buildable area is defined
as an area free of flooding, avalanches, or with a slope less than 40
percent. A site grading and drainage plan is required for developments
and subdivisions primarily for purposes of insuring the protection of
off-site property owners* However, on "hillsides, excessive grading
should not be permitted . . ." (Mote: the word "should" is used rather
than "shall" or "will", and the term excessive is not defined.) A. land-
scaping plan is also required indicating what vegetation is to be re-
tained and what is to be removed and replaced, primarily so that the
amount of Che performance bond for making sure landscaping and mainte-
nance are carried ouc can be determined. Guidance is provided chac Che
removal of vegetation "generally should be limited to removal of those
essential for development of the site." Although it is not clearly
stated, it aust be assumed chat any performance bond will be limited to
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che period of construction, a perpetual performance bond being imprac-
tical. Therefore, it appears there is no guarantee that installed
landscaping will be maintained.
In fact, the Town of Vail zoning ordinance contains few standards
which limit the generation of pollutants during construction. Vir-
tually any portion of a development 3ite may be disturbed at any time,
and no provision for stabilizing disturbed areas is included. Inter-
pretation of existing ordinances by an environmentally sensitive staff
of administrators and the cooperation by responsible developers rather
than stated policies or specific regulations appears to be che main
factor controlling construction activities.
The Eagle County Zoning Ordinance allows a somewhat higher percent-
age of lot coverage than the Town of Vail for low density residential
zones, and comparable percencages for high density and commercial
zones. See Reference 28. Minimum loc sizes and allowable floor area
ratios are also similar with Eagle County having somewhat lower minimum
loc sizes and allowable floor area ratios. However, the Eagle County
ordinance includes slope development limitations which require an in-
crease in minimum lot size and a decrease in the maximum floor area
ratio with increases in slope up to 30 percent. For greater slopes,
development is not permitted except under a special use permit. The
slope developmenc limitations' primary effect is to reduce development
density which in turn reduces the area likely to be disturbed during
construction. Grading and drainage plans are required by the Eagle
County Subdivision Regulations, and a landscaping plan is required for
subdivisions of three or more units, or where there is a potential for
damage to vegetation. See Reference 29. A minimum requirement of
landscaping plans is provision for revegetation of areas disturbed.
The Design and Improvement Standards of Che Subdivision Regulations
recognize che special problems of locating and constructing streets and
roadways in areas of slopes greater than 20 percent, and require grad-
ing and revegecacion plans as a way of insuring scable slopes and mini-
mum erosion. The standards also contain a provision requiring the
applicant co demonstrate chat his proposed development "does not result
in reasonably avoidable degradation of streams." They also state, "in
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no case will a development be allowed to affect either the point, the
magnitude, the depth or the velocity of drainage flows upstream or
downstream from said development." In general, the Eagle County regu-
lations reflect an awareness that development conditions may pose
problems which should be resolved during project planning, review, and
approval. However, there are no limitations on time, duration, or ex-
tent of construction activities, and minimal requirements for disturbed
area stabilization or revegetation.
Both Eagle County and the Town of Vail require Environmental Impact
Reports for any proposed project which may significantly affect the
environment both during construction or on a continuing basis. See
References 27 and 28. Such reports, if properly prepared, can be very
useful in disclosing undesirable effects in subject areas not covered,
or minimally covered, by zoning and subdivision regulations. Further,
in discussing ways to minimize or eliminate unwanted effects, condi-
tions co project approval may be suggested and adopted. A good EIR,
however, is not a good substitute for good planning which recognizes
environmental constraints.
It is generally recognized that the first step in reducing the
generation of pollutants during construction is to carefully plan the
time and extent of vegetation removal and soil disturbance, and limit
the length of time surfaces are left exposed. See References 2, 30 -
34. Limitations on the percent of land chat can be covered by build-
ings, roadways, parking lots, etc., is one way to influence the amount
of land that has to be disturbed to construct the project. One of the
strictest land use ordinances in the nation, adopted by the Tahoe
Regional Planning Agency (TRPA), establishes land coverage percentage
limitations based upon land capability as established by conditions of
soil, 3lope, geology, and climate. See Reference 35. The general
provisions limit land coverage (anything that prevents normal precipi-
tation from directly reaching the land surface) to one co 30 percent
depending on land capability. Tourist commercial districts have a 35
percent limitation if for residential uses, and 50 percent for other
uses. General Commercial Districts are limited to 70 percent land
coverage. All other zoning districts must comply with the general
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provisions. Limitations on the cine, extent and duration of vegetation
removal and grading are contained in the TUPA. Grading Ordinance. See
Reference 36. Several key provisions of this ordinance of interest to
this review are:
0 An information report and grading plan as well as a revegetation
and stabilization plan are required.
0 Appropriate barriers shall be provided around all native
vegetation proposed for retention and entry by vehicles
during construction is prohibited.
° Grading and filling are prohibited from October 15 through
May 1.
0 No solid or liquid waste materials including earthen materials
will be discharged, or deposited in such a way as to cause
indirect discharge, into Lake Tahoe or any of its tributaries.
0 Sediment or other material deposited in Lake Tahoe, its flood
plains or its tributaries will not exceed that which would have
been deposited if the land had been left in its natural state.
A permit is required before any grading, filling or clearing of
vegetation except when the excavation proposed does not exceed four
feet or the fill three feet at their deepest points, and the area does
not exceed 200 square feet. Excavations for basements and footings for
a building are excluded from permit requirements, as is clearing of
vegetation from an area not exceeding 1,000 square feet. Work by
public agencies or exploratory excavations are also excluded.
The land coverage and grading restrictions used in the Tahoe region
are representative of the types of controls employed to control pollu-
tion of streams and lakes- They are perhaps some of the most restric-
tive regulations to be found in this country. This is because they are
intended to help protect a unique national visual resource, Lake Tahoe,
which is famous for the clarity of its waters.
The zoning and subdivision ordinances, regulations, and standards
of the Town of Vail and Zagle County are reasonable regarding minimus
lot sizes, densities, and lot coverage. They are weak in providing
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standards co control the generation of pollutants resulting from con-
struction activities. Grading ordinances and erosion control plans are
common or strongly recommended practice in other areas with erosion
problems, see References 2, 30, 36, 37 and 38; and it is recommended
such ordinances be adopted by land use agencies within the Upper Eagle
Valley. The major provisions that can be identified at this time are:
0 Prohibit grading and filling activities before May 15, or
until the site is clear of snow, and after September 15 for
elevations below 9,000 feet*
" Require all graded and or exposed areas to be revegetated
and or stabilized as soon as possible, but no later than
September 15.
* Require a grading plan specifying the time, location, and
extent of grading, and che time and methods for stabilizing
exposed areas.
The administrative guidelines given under Policies 5 and 6 of the
NVCCOG Plan recommend vegetation disturbance and erosion control plans
which would include many of the provisions usually found in a grading
ordinance; however, some provisions, such as water quality objectives,
may be more properly made a part of land use or subdivision ordinances.
More specific recommendations will emerge from the following discus-
sions .
Practices to limit the entry of pollutants into runoff are not spe-
cifically addressed except by listings under Policies 5 and 6 of the
NVCCOG Plan. The two most common practices, neither of which are spe-
cifically addressed in Eagle County or Town of Vail ordinances or regu-
lations, are to divert the upslope runoff around the construction site,
and onsite detention of precipitation falling on the site. See Refer-
ences 15, 30, 31, 32 and 37. Runoff diversion is usually accomplished
by the construction of barriers, dikes, and diversion channels, and are
installed before any vegetation removal or grading takes place onsite.
Onsite detention provides for percolation of runoff into the ground and
an opportunity for suspended soil particle co settle out before the
runoff is discharged off-site. One other practice sometimes mentioned
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is co stockpile soil in a Location and in a manner which minimize ero-
sion. The approach is co consider che stockpile as a separate 3ice
within che construction site and to protect it by runoff diversions and
employ settling basins. These practices are normally carried out under
the provisions of a grading and erosioa control plan.
Most policies and practices are aimed at controlling the amount of
polluted runoff leaving a construction site by che methods discussed
above. This is largely because it is easier to control at the source
than afterward. The basic method of controlling the entry of polluted
runoff into streams it to divert che flow either to a vegetated area
where the vegetation slows the flow, traps sediments and allows some of
che water to percolate into the ground, or to an off-sice sedimentation
basin where settling occurs before waters are discharged to a stream.
Of these wo methods, the second is usually preferred because trapped
sedimencs can and should be occasionally cleaned ouc. This is not
possible with che first method and large amounts of sediment may
smother vegetation and eliminate its effectiveness as a sediment crap.
For runoff flows which are not heavily polluced, 20-40 mg/1 of
suspended sedimencs, flow over vegecaced areas is an economical and
effective technique. For this reason, natural drainage ways, tiaCural
depressions such as swales, draws or hollows which only carry wacer
during snow melt or rains, should be preserved. Therefore ic is re-
commended chat grading or filling and site development be prohibited
within nacural drainage ways or, ac the minimum carefully controlled.
If polluted runoff enters a stream either by direcc discharge or
by overland flow, the impact on the stream can be reduced by preserving
the stream's ability to accommodate che polluced flows wich minimum
impacc. This is accomplished by preserving the stream channel and
bordering riparian or streamside vegetation and associated wetlands.
The importance of streams and their associated environments is recog-
nized in Policy 3-Encroachmenc, of the MWCCOG Plan. The practices
recommended under this policy include scream channel setbacks, flood-
plain restrictions, wetland protection, strict controls on stream
channel modifications, and che acquisition of stream environment zones
through land purchase, easements, purchase of development rights, or
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land exchanges. Some of those practices have been and are being used
in che Upper Eagle Valley. For example che Town of Vail has purchased
important wetlands on Gore Creek- Both the Town of Vail and Eagle
County include stream setback and floodplain restrictions in their
subdivision and zoning ordinances and regulations. See References 27
and 29. Eagle County requires chat a strip of land at least thirty
feet in width measured from che high water nark on each side be pre-
served in its natural state. Some circumstances may require a greater
width. Footpaths, bridges, fences, irrigation or flood control and
erosion works as well as underground utilities may be located within
these scream setbacks* The Town of Vail requires a setback of fifty
feet from the center of the Gore Creek stream channel or thirty feet
from the center of other stream channels. It is further staced thac
nacural creek or scream channels may not be rechanneled or changed.
The Tahoe Basin Water Quality Management Plan strongly restricts
development wichin scream environment zones. See Reference 39. These
zones are defined by a combination of minimum buffer zones, flood-
plains, riparian vegecacion, and alluvial (wacer deposited) soils. The
minimum buffer zones, measured from the center of che channel, are:
(1) Twenty-five feet for drainage ways and first order streams.
A. drainage way is a topographic depression which conveys
surface water to major or minor streams during storms and
snowmelt periods. A first order stream is any mappable, USGS
7.5 minute series, unbranched tributary.
(2) Fifty feet for minor (second order) screams. Second order
streams are formed by the combined flows of cwo or more un-
branched first order streams.
(3) One hundred feet for major streams (third order or higher).
Scream environmenc zones are defined by ooundaries ocher Chan
minimum buffer zones in che Tahoe Basin Wacer Quality Management Plan.
The boundary is defined as the limit furchesc from che scream or drain-
age way of eicher che 100-year flood plain, che limit of riparian
vegetation, the limit of alluvial soil cypes, or che minimum buffer
width. In much of che Upper Eagle Valley, such a definition would
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exclude most of the developable area, che alluvial plains, from most
types of development.
The stream secback requirements for Eagle County and Town of Vail
cannot be directly compared because the Town of Vail setback distance
is measured from the center of the scream channel. If a thirty-foot
channel width is assumed for the West Vail reach of Gore Creek, a third
order stream, che following setbacks from the channel centerline would
result.
Town of Vail - Fifty feet
Eagle County - Fifty feet
Tahoe 3asin - One hundred feet
A similar result would be obtained if a tributary to Gore Creek were
used in the comparison. That is che Tahoe minimum buffer widths would
be about twice those of Eagle County and the Town of Vail. Administra-
tive guidelines suggested under Policy 3 of che NWCCOG Plan recommend
setbacks ranging from 25 to 150 feet. It is not clear whecher chese
recommendacions are for secbacks from che channel cencerline or from
the high water mark.
Flood plain development restrictions, aimed at protecting life and
property, are another means of protecting screamside environments. For
example, Eagle County divides the 100 year floodplain, that land area
flooded by a storm that happens on the average of one time every 100
years, into high and low hazard areas. See Reference 29. High hazard
areas are where flood flows with velocities equal to or greater Chan
three feec per second or flood wacer depchs equal co or greacer Chan
one foot may occur, and chese areas are reserved for open space. Low
hazard areas are che remainder of che floodplain, velocities less Chan
chree feec per second and depchs less Chan one fooc, wherein che area
can be used for any purpose qoc requiring permanent structures, che
storage or processing of hazardous materials, solid waste disposal
sices, onsice sanitary waste disposal (such as septic tanks). Gen-
erally che floodplain rescriccions and stream secback requiremencs or
local agencies in che Upper Eagle Valley represenc a reasonable and
prudenc compromise becveen che requiremencs of public safecy and
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welfare, and Che limited supply of economically developable land. It
would appear imprudent, for example, to increase scream setback re-
quirements so as to force development in areas of steeper slope and
greater erosion potential. Rather, it appears a more realistic
approach is to limit the generation and pickup of pollutants at the
source. However, it is recommended that a minimum setback requirement
of twenty feet from the centerline of a drainage way plus restrictions
on grading and filling within a drainageway as previously discussed
would be of considerable value in protecting the streams of the Upper
Eagle Valley.
The previous discussions recommended that specific water quality
standards be incorporated into land use or subdivision ordinances,
drainage ways be protected from development or construction activity,
and grading ordinances be adopted' A suggested wording for a water
quality standard is:
Mo development, land use, enterprise, or human activity will be
allowed to affect the water quality or point, magnitude, depth, or
velocity of drainage from said development, Land use, enterprise,
or human activity except as provided as follows:
a. Construction activities governed by the Grading Ordinance
may exceed the Basic Water Quality Criteria (BWQC) by a
factor of two for one rain-storm event occurring during
one construction year, or
b. A net water quality benefit to any perennially flowing
stream, or property which drainage flows traverse, can be
demonstrated.
The Basic Water Quality Criteria for surface flows from any site
of development, land use, enterprise, or human activity are:
Total Suspended Solids - 25 mg/1
Total Dissolved Solids - 100 mg/1
Total Nitrogen as Nitrogen -1.0 mg/1
Oil and Grease - 2.0 mg/1
These Basic Water Quality Criteria may be adjusted based upon
actual measurements and calculation which demonstrate, to the
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satisfaction of the Environmental Health Officer of the Town/
County, that the average water quality of drainage from the site
of development, land use, enterprise, or human activity in its
natural state exceeds the Basic Mater Quality Criteria. In no
caae will the allowable water quality of drainage from the site of
development, land use, enterprise, or human activity be of worse
quality than the quality of drainage entering said sites if said
quality exceeds the Basic Mater Quality Criteria.
The wording suggested for protection of drainage ways, which is
recommended to be made a part of design and review standards, is:
Any site, lot, parcel or portions thereof which is situated in a
drainage way shall not be considered as a buildable area suitable
for development. A drainage way is that area twenty feet on
either side of the centerline of a topographic depression which
conveys a surface water flow of one cubic foot per second during
storms of two-year frequency or during snowmelt periods.
A suggested grading ordinance, based upon actual and recommended
ordinances from References 36 and 37, but tailored to conditions in the
Upper Eagle Valley is presented in Appendix B.
POLLUTANTS FROM AREAS OF HUMAN ACTIVITY
Four of the ten NWCCOG Plan Policies address the problem of pollu-
tion generated within areas of human activity. These are:
Policy 4- The surface and ground waters of the region shall be
protected by public investments in roads, water sup-
plies, sewage treatment systems, and other public
facilities and services which would encourage land use
and development activities in locations where water
quality impacts will be minimized. Conversely, such
investments shall be made to discourage land use and
development activities in locations where severe water
quality impacts aiay be caused. Such public investment
policies shall also recognize the protection of flood-
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plains, geologic hazards, wildlife habitats, wetlands,
shorelines and prime agricultural land.
Policy 7- The surface and ground waters of the region shall be pro-
tected from land use activities creating impervious cover
conditions which would cause a long-term reduction of the
quality and quantity of natural groundwater recharge from
precipitation.
Policy 8- The surface and ground waters of the region shall be pro-
tected from land use activities which would alter che
drainage patterns, velocities, volumes, and physical,
chemical and biological characteristics of scorn water
runoff which would cause significant degradation of water
quality or would Impair the currenc or designated uses of
the region's waters.
Policy 10-The surface and ground water resources of the region
shall be protected from the uses of pesticides, ferti-
lizers, algacides, road salts, and ochec chemicals which
would temporarily or permanently cause a significant
deterioration in water quality conditions or impair the
current or designated uses of these waters.
The intent of policy 4 - Public Facilities and Services is to in-
fluence the location of land use and development activities so as to
minimize water quality impacts, and the administrative guidelines cite
Policy 3 - Encroachment administrative guidelines. Thus the pollution
generating potential of public facilities and services themselves are
indirectly addressed, mostly in a policy objective under Policy 3 -
Encroachment which states in part; "to regulate...solid waste disposal,
construction of sewage treatment systems, storage or processing of
materials potentially injurious to water quality, and all other land use
activities in locations which would be detrimentalA somewhat more
specific administrative guideline recognizing the pollutanc generating
characteristics of public facilities, such as roadways and corporate
yards, and che importance of locating these facilities so as to minimize
water quality impacts vould appear reasonable.
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It is noc known if proposed County, Town or special district facil-
ities are subject to the same review for conformance co County or Town
design or improvement standards as are private sector proposals and
applications. For example, it appears chat proposed projects by Eagle
County or the Town of Vail are exempt from the EIR requirements of the
respective agencies* These local agencies must comply with State and
Federal laws and regulations which in many cases establish standards and
procedures with which the agencies must comply. However, local agencies
retain considerable control and descretion over their activities. Many
states and municipalities in the county have so-called mini-NEPA laws
patterned after the National Environmental Policy Act which, among other
requirements, established the EIS/EIR process- Many of these laws and
ordinances restrict or exempt its application to the governing public
agencies' projects. It should be remembered; however, that the original
application of the first mini-NEPA law, the California Environmental
Quality Act (CEQA) was only to proposed public agency projects. Court
decisions and amendments extended it two years later to private sector
projects requiring agency permits or entitlements. It is recommended
that the requirements for EIK's be removed from the Eagle County and
Town of Vail subdivision and zoning ordinances, and be embodied in a
separate ordinance applicable to any project requiring the descretionary
funding, approval, permit or entitlement by the governing body.
Policy 7 - Impervious Cover, recognizes that percolation is prefer-
able to surface runoff in protecting the quality and quantity of ground
water. It fails co explicitly recognize that Impervious cover, par-
ticularly surfaces for vehicle travel and parking, are a primary source
of pollutants through the deposition and washoff process discussed in
Section VI of this report. The administrative guidelines of this
policy recommend the regulation of impervious cover particularly in
areas with ground water of regional importance.
The previous discussion in chis section of Che report on pollutants
from construction reviewed and assessed local agency ordinances and
regulations which concrol the degree of impervious cover allowed for
various types of land use. The general approach is to limit the area of
impervious cover, but there are situations when impervious cover is
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preferable over existing conditions of use. For example, che Anchorage
208 Plan recommends the paving of dirt roads, streets and parking areas,
although for Anchorage, the water quality benefits alone seldom justify
the cost. See Reference 38. Further, maintenance of roadways is im-
portant because it was found that streets in poor condition generate
total solids loadings 2-1/2 times as great as streets in good condi-
tions. Many of the heavily traveled streets and highways in the Study
Area are new or are well maintained by the Colorado State Department of
Highways. Therefore, the maintenance problems typical of older roadways
are not widespread at this time.
The administrative guidelines of Policy 8 - Storm Water, recommend
that the hydrologic characteristics of future developments should be
similar to pre-development characteristics. Further, storm water dis-
charges from future developed areas over five acres should be regulated
by 3torm discharge permits, similar to National Pollution Discharge
Elimination System (NPDES) permits, where effluent requirements would be
established on the basis of periodic storm discharge quality monitoring.
It is also recommended that further studies, such as this study, should
be undertaken to determine the feasibility of requiring water quality
impacts reports for future developments of over 25 units or greater than
five acres of impervious cover.
The policy on storm water fails to recognize that 70 to 80 percent
of annual runoff, and a higher percentage of annual pollutant load,
occurs during snownelt, at least in the Upper Eagle Valley. This fail-
ure is understandable given the data available at the time the NWCCOG
Plan was prepared. The maintenance of hydrologic characteristics, as
recommended under Policy 8, is desirable because it implies a degree of
onsite detention to achieve chis goal, and because it would minimize
downstream or offsite accelerated channel or drainage way erosion.
Storm water discharge permits would have little direct effect in reduc-
ing the generation of pollutants, and implies that the development plan-
ning criteria of the land use agency are ineffective. Monitoring of
3tom water and snowmelc discharge quality can give valuable information
to guide planning for future developemnt. However, the requirement for
water quality impact reports would be redundant for local agencies which
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require environmental impact reports- The general test for the need to
prepare an SIR, potential adverse environmental impacts, is also more
appropriate than the criteria suggested for water quality impact re-
ports .
Pesticides, fertilizers and other chemicals are addressed in Policy
10. Because the uSe of pesticides, herbicides and fertilizers has not
been documented nor the impact of such use on water quality, the admin-*
istrative guidelines recommend, for the interim, that the use of these
substances be strictly Limited in flood plain, unstable and aquifer
areas. Other areas of the region should have the use of pesticides,
herbicides and fertilizers managed.
The administrative guidelines on the use of deicing chemicals are
fairly explicit and recognize the importance of this source, or gen-
erator, of pollutants. These guidelines are:
0 Plowing rather than sanding, salting or other chemical applica-
tion should be emphasized during early storm periods.
9 Salt and other chemicals should be applied only when removal of
snow and ice cannot be accomplished by blading, plowing, or
sanding.
* Sand and chemical application rates should be determined to re-
flect the lowest limits of chemical usage.
° Measures should be taken to avoid use of sand and chemicals in
and adjacent to environmentally sensitive areas including
streams, lakes, ponds, wetlands, potential aquifers and flood-
prone areas.
9 Chemically treated or sanded snow and ice should not be dumped
where melt can flow directly into surface waters.
All of these guidelines represent good practice and should be fol-
lowed. The last guideline deals more specifically with the entry and
transport of pollutants from melting disposed snow and ice than with the
generation of pollutants. However, it is better to discuss it here.
The Municipality of Anchorage discovered that waste snow collected at
five dump sites had dissolved solids contents and iron and lead concen-
trations exceeding criteria for drinking water and aquatic life, and had
concentrations of oil and grease up to 710 mg/1. See Reference 38.
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Limited 3tream sampling did not conclusively link, runoff from snow dis-
posal sices co instream violations of water quality criteria. In the
Anchorage 208, a formalized site selection procedure with monitoring of
surface discharges and aquifer quality was recommended. Common practice
in the study area is to dump wasted snow and ice directly into streams
or on stream banks. The snownelt runoff quality monitoring of culvert
discharges conducted in the spring of 1978 indicated very poor quality,
and it is reasonable to assume snow removed from roadways and parking
areas contains significant quantities of pollutants. It is therefore
recommended that the dumping of removed snow and ice in streams, drain-
age ways and on adjacent land be prohibited. It is further recommended
that dump sites be located where the melt will infiltrate into the soil
instead of flowing into streams, and where the ground waters will not be
adversely affected.
Two of the previously discussed NWCCOG Plan policies contain pro-
visions which limit the entry of pollutants into runoff. The Policy
8-Storm Mater administrative guidelines on maintenance of hydrologic
characteristics is of value in influencing this aspect of the pollution
process. Land development usually results in an increase in the depth
and velocity of runoff from a site because of topographic changes and
drainage facilities designed to promote the rapid removal of storm
waters, and because of the Increase in impervious areas* In maintaining
hydrologic characteristics, velocity control is accomplished which In
turn minimized the suspension of pollutants in runoff flows. Eagle
County currently prohibits changes in hydrologic characteristics, where-
as the Town of Vail requires the submittal of a drainage plan for pro-
posed developments. The TRPA Subdivision Ordinance requires that sub-
divisions shall be planned, designed, constructed and maintained so as
to provide a system by which water within a subdivision will be removed
without causing harm or damage co the natural environment, or to pro-
perty or persons within the subdivisions or in ocher areas. Further,
subdivisions will al30 be designed, constructed and operated in such a
way to assure that waters are drained in such a manner that they will
not cause erosion outside the subdivision to any greater extent than
would occur in the absence of the subdivision or improvement.
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Ic Is useful co discuss the measures that can be taken co minimize
or eliminate changes in Che hydrologic characteristics of a site after
it is developed. The basic approach generally recommended is onsice
detention. See References 34, 37, 38, and 39. Its purpose is twofold
in chat temporary detention promotes infiltration and reduces the
quantity of surface runoff, and the remaining runoff is discharged at a
controlled race (lower flows over longer periods of time). Another
advantage of onsite detention is chat it gives a chance for pollutants
suspended in runoff to settle out, and reduces the amount discharged
offsice. The three main methods of onsice decention are (1) rooftop
ponding, (2) plaza, parking lot, tennis court, etc. ponding, and (3)
open space and grassed area ponding. Each of chese methods is augmented
with measures co improve infiltration such as pervious pavements, infil-
tration trenches, and roof dripline crenches. These mechods in some
cases may require modifications to che building code. However, there is
a significant body of experience with these mechods, and various ways in
which they may be implemented, to demons erace chac che NWCCOG admiais-
tracive guideline on preservacion of hydrologic conditions is feasible
and should be implemented in che study area.
The administrative guideline on the storage and handling of toxic
substances under Policy 10-Pescicides, Fertilizers and Other Chemicals
recognizes an important element of nonpoint pollution control. The
guideline states in part:
0 Toxic subscances should not be stored on potential aquifer
recharge areas and unstable slopes- Restrictions should be
extended to floodprone and other hazardous areas.
* Storage of toxic subscances should be continuously monitored
throughout che remainder of the Region.
" All materials should be kepc in containers and/or under cover,
well protected from precipitation and stormwacer flows.
0 All storage areas should be kept clean of spilled material.
9 Eandling and moving of materials should be limited as much as
possible.
66
-------
One does not have to look very hard in the Upper Eagle Valley to find
numerous instances of hazardous material stored in locations or in ways
that could pollute runoff. The zoning and subdivision regulations of
land use regulatory agencies in the Upper Eagle Valley contain frequent
references to the use and storage of hazardous and toxic substances.
For example, the Town of Vail*3 development standards for gasoline
service stations require that "all storage of goods shall be completely
within a structure." Uses which may involve the use or stroage of toxic
materials are not permitted in Greenbelt and Open Space Districts. See
Reference 27. Eagle County has included several performance standards
for industrial and commercial land uses in its zoning ordinance which
address the storage of hazardous materials, and specifically state, "no
water pollutant shall be emitted by the manufacturing or other proc-
essing". See Reference 28. The Subdivision Regulations state that
flood hazard areas should not be used for "storage or processing of
materials that in times of flooding are buoyant, flammable, explosive,
or otherwise potentially injurious to human, animal, or plant life, or
should not be used for solid waste disposal sites." See Reference 29.
Emphasis added. The NUCCOG administrative guideline recognizes that the
manner in which activities involving the use, processing or storage of
hazardous materials are performed is as important as zoning and land use
restrictions on where such activities can take place. Subdivision
regulations and zoning ordinances, however, are not effective enforce-
ment mechanisms for insuring that toxic substances are stored and
handled properly. Such enforcement mechanisms are normally found under
a public health code. Accidental spills or intentional dumping of
hazardous materials in streams or drainage courses is easily documented
in the Upper Eagle Valley- A. hazardous substance spill prevention and
containment ordinance patterned after similar EPA regulations may be an
effective approach. However, closer examination of public health codes
and stricter enforcement of existing laws and ordinances may be all that
is necessary.
Policy 9-Domestic, Municipal, Industrial Waste deals primarily with
the control of point source pollution to protect ground water and sur-
face water quality. However, it also addresses a very important non-
point pollution source which must be carefully controlled to prevent
67
-------
offsite transport of pollutants either by runoff or by percolation to
ground waters. Two policy objectives under this policy clearly stac£
the problem.
9 To regulate development of solid vasce disposal sites includng
residuals from wastewater treatment in accordance with sound
conservation practices, giving consideration to potential
pollution problems inherent in proposed sites.
0 To recognize the sensitivity of regional and local ground
water aquifers to pollution from waste discharges or seepage
from waste disposal sites.
Fortunately, there are no solid waste disposal sites within the
study area. Any future sites which may be proposed within the study
area will probably have to meet requirements established in the near
future by the State under the Federal Resource Conservation and Recovery
Act.
There are certain types of human activities which generate pol-
lutants, but are not generally addressed in local agencies' plans and
policies because they are more likely to occur in the study area on
lands controlled by federal agencies such as the U.S. Forest Service.
These activities include logging, off-road recreational vehicle use,
hiking and camping. The White River National Forest is likely co ex-
perience increased pressure for recreational uses. Hikers, for example,
create solid wastes, sanitary wastes, and damage vegetation cover so
that soil erosioo is accelerated. The Forest Service has a difficult
task in deciding between use and abuse. The local governmental agencies
in the Upper Eagle Valley have a direct interest in the consequences of
chat decision.
Controlling the entry of pollutants into runoff is usually accom-
plished by simple "housekeeping". Private land owners are usually ex-
pected, or required through liccer concrol ordinances, co keep cheir
property free of litter, and not deposit litter, leaves, etc. into
street gucters or drainage channels where they may be picked up by scorn
or snowmelt flows. The greatest "housekeeping" burdens, however, gen-
erally fall on public agencies such as street departments or public
68
-------
works departments. They often are responsible for litter collection,
street sweeping, catch basin cleaning, and cleaning of drainage ways.
Few of these activities, however, occur in the study area to any extent
for various practical reasons, and none are addressed in NWCCOG Plan
policies, policy objectives, or administrative guidelines. Street
sweeping is limited except for spring cleanup of highway sanding
materials by the Colorado Department of Highways, because a relatively
small percentage of the developed areas have curbs and gutters. Catch
basins are uncommon, and drainage ways and stream channels are usually
presumed the responsibility of the property owner. One recent analysis
of the effectiveness of street sweeping in Anchorage, Alaska, indicated
that a sweeping frequency of twice a month is effective in removing
about 25 percent of suspended solids, coliform, and phosphate from rain-
fall runoff pollutant loads. Effectiveness in reducting nitrogen
compounds, chemical oxygen demanding or biochemical oxygen demanding
substances was only about 10 percent. Sweeping once a month was com-
pletely ineffective, but a doubling of frequency to four times a month
roughly doubled effectiveness. See Reference 34. However, this evalua-
tion was for rainfall runoff. Under snowmelt runoff conditions, runoff
is characteristically of lower volume and velocities so that initially,
dissolved and very fine materials are picked up and washed off into
streams. There is little that can be done to control the entry of these
types of materials into snowmelt runoff once they have been generated.
The entry of larger and less soluble materials can be effectively con-
trolled and should be as they represent perhaps 50 percent or more of
the total available pollutant load. See Reference 16. A suggestion
made earlier in this report, and a recommendation included in the
Anchorage 208 Plan, is to conduct a spring and fall cleanup campaign.
The spring campaign would begin when pavements are essentially free of
ice and snow, but not necessarily dry, and include intensive street and
parking lot sweeping, catch basin cleanout, litter pickup, road main-
tenance and repair, and clean out of storm drainage ways. The campaign
should be repeated in the fall before first snow to remove materials,
debris and litter before it becomes trapped under snow cover, and be-
comes a source of pollution next spring. Such campaigns 3hould concen-
trate on developed areas with intense uses, and if spearheaded and
59
-------
coordinated by public agendas, should result la significant partici-
pation by enlightened private interests.
Policy 3 - Encroachment, Policy 5 - Vegetation Disturbance, and
Policy 8 - Storm Water each contain important elements which address the
methods of controlling the entry of polluted runoff into streams, and of
preserving a stream's capacity to absorb and recover from the impact3
from polluted discharges* The NWCCOG Plan policies and administrative
guidelines as well as local agency regulations are more fully discussed
under pollution from construction.
The two most important methods are maintenance of grassed or vege-
tated drainage ways and streamside areas and diversion. See References
33, 34, 37, 38, and 39. The former method recognizes the effectiveness
of vegetated areas in trapping pollutants and promoting infiltration.
Diversion to holding ponds or land treatment areas or to storm water
treatment facilities is difficult to accomplish in already developed
areas, but can be incorporated into newly developing areas at minimal
cost if holding/percolation ponds or land treatment is incorporated
during area planning. Diversion and treatment, structural control, is
generally the most costly method. The earlier recommendations pertain-
ing to the preservation of drainage ways through set-backs and limits on
development are again suggested.
CONTROL TECHNIQUES
The previous discussion has focused on a review of existing and
recommended policies, ordinances, and regulations of local and regional
government agencies in the study area in light of approaches and experi-
ences available from other parts of the United States. The general con-
clusion is that the best approach is to control the generation of off-
site transport of pollutants at the source. Once pollutants leave a
site in runoff, it is much more difficult and expensive to minimize im-
pacts on streams and other bodies of water. The question remains, how-
ever, "what are the physical techniques that planners, engineers, con-
tractors, and others can use to control non-point source pollution?"
Volume 2 of this report attempts to answer this question by explaining
70
-------
various techniques, cheir effectiveness, and their advantages and
disadvantages.
An estimate was made of the effectiveness of a non-point source
control program in improving in-stream water quality at station GC-U on
Gore Creek, near its confluence with the Eagle River. The results are
given in Table 12. Admittedly optimistic estimates of the effectiveness
of various control techniques were used in order to provide a "best
attainable" estimate of water quality. The results indicate that a
control program could possibly reduce suspended sediments and total dis-
solved solids concentrations to near pre-development levels, and that
concentrations of 300 and total Nitrogen could be significantly reduced.
However, Phosphorus and Lead concentrations would remain relatively
high. Phosphorus is not of great concern in running streams, but Lead
is a toxic metal for aquatic life. However, elevated concentrations of
Lead appear to be strongly influenced by background conditions.
TABLE 12. Estimated Annual Average Gore Creek In-Stream
Concentrations, mg/1 at Station GC-14
Total
Suspended Dissolved Total Total Total
Sediments Solids Bod Phosphorus Nitrogen Lead
1958 conditions
(Predevelop-
ment)
1978 conditions
1978 conditions
with controls
11 70
22 110
12 86
0.26 0.09
1.8 0.21
1.12 0.13
0.30 0.009
1.55 0.019
0.61 0.015
71
-------
REFERENCES
1. Anon., "Final Environmental Impacc Statement - Upper Eagle Valiey
and Vail Wastewater Facilities Plan," U.S. Environmental Protection
Agency Report EPA-908/5-77-003, October, 1977.
2. Anon., "Draft Areawide Water Quality Management Plan for Eagle,
Grand, Jackson, Pitkin, Routt and Summit Counties," prepared by
Comarc Design Systems, Wallace McHarg Roberts & Todd, North West
Colorado Council of Governments for the North West Colorado
Council of Governments, March, 1978.
3. Bntton, Linda J., "A Water-Quality Inventory of Surface Water in
Eagle, Grand, Jackson, Pitkin, Routt, and Summitt Counties, Colo-
rado," USGS Preliminary Report prepared in coopration with the
North West Colorado Council of Governments, 1977.
4. Giles, T. F., Brogden, R. E., "Water-Quality Data for the Eagle
River Valley in the Vicinity of Eagle and Vail, West-Central
Colorado," USGS Open-file report 76-812, 1976.
5. "Proposed Water Quality Standards for Colorado," by the Colorado
Water Quality Control Commission, November 17, 1977, effective
July 20, 1978.
6. Rice, L., "Hydrology-Water Quality Impact Study of Avon-Beaver
Creek, Colorado," report prepared by Leonard Rice Consulting Water
Engineers for Vail Associates, Inc., June, 1974.
7. Vanoni, V.A., Sedimentation Engineering, prepared by the ASCE Task
Committee for the Preparation of the Manual on Sedimencation of the
Sedimentation Commitcee of the Hydraulics Division, published by
the American Society of Civil Engineers, 345 East 47th Street, New
York, New fork 10017, 1975.
8. Overton, D.E., Meadows, M.S., Stormwater Modeling, Academic Press
Inc., Ill Fifth Avenue, Mew York, New York 10003, 1976.
9. Linsley, R.K, Hydrology for Engineers, second edition, McGraw-Hill,
Inc., New York.
10. Falletti, D., Russell, R.L., "Hydrology Report, Meadow Montain
Management Unit, Holy Cross District, White River National Forest,"
U.S. Department of Agriculture Forest Service Rocky Mountain Region,
circa 197 5.
11. Terzagni, K., Peck, R.3., Soil Mechanics m Engineering Practice,
John Wiley i Sons, New York, New Yorx.
12. Leaf, C.F., "Sediment Yields from Central Colorado Snow Zone,"
Journal of the Hydraulics Division, American Society of Civil
Engineers, V.96 Hyl, January 1970.
72
-------
L3. Flaxman, E.M., "Predicting Sediment Yield in Western United States,"
Journal of the Hydraulics Division, American Society of Civil Engi-
neers, Vol. 98 HY12, December 1972.
14. Sorrentmo, C.T., Personal communication, Colorado State Department
of Highways, July 13, 1978.
15. Hotes, F.L., Ateshian, K.H., Sheikh, B., "Comparative Costs of Erosion
and Sediment Control, Construction Activities," U.S. EPA Report
EPA-430/9-73-016, by Engineering-Science, Inc., under contract No.
68-01-0755, July 1973.
16. Sartor, J.D., Boyd, G.3., "Water Pollution Aspects of Street Surface
Contaminants," EPA Report R2-72-081, November 1972.
17. Bradford, W.L., "Urban Stormwater Pollutant Loadings: A Statistical
Summary Through 1972," Journal of Water Pollution Control Federation,
April 1977.
18. Urbonas, B., Tucker, L.S., "Stormwater Quality—What is the Problem?"
Urban Water Resources Research Council session on Urban Runoff
Quality—Measurement and Analysis, ASCE Convention, October 1977.
19. ."Urban Runoff Management Plan," by Wright-McLaughlin
Engineers for City of Aspen, Colorado, August 1973.
20. , "Steamboat Spring Facilities Plan," Vol 1, May 1976.
21. Colston, N.W., "Characterization and Treatment of Urban Land Runoff,"
Environmental Protection Technology Series, EPA-670/2-74-096,
December 1974.
22. Weibel, S.R., Anderson, R.J. Woodward, R.L., "Urban Land Runoff
as a Factor in Stream Pollution," J. WPCF 26, No.7, July 1964.
23. , "Stormwater Pollution from Urban Land Activity,:
prepared by AVCO Economic Systems Corporation, Water Pollution
Control Research Series, Federal Water Quality Administration
Report No. 11034 FKL, July 1970.
24. , "Water Pollution Aspects of Urban Runoff," prepared
by APWA, Water Pollution Control Research Series, Federal Water
Quality Administration Report No. WP-20-15, January 1969.
25. Fox, R.L., "Laboratory Analysis of Upper Eagle Valley Water Quality
Samples," U.S. EPA Region VII Surveillance and Analysis Division,
March-July 1978.
26. Livingston, R.K., Personal communication of Preliminary Stream Dis-
charge, Sediment Concentrations and Water Quality Data, Water
Resources Division, U.S. Geological Survey, May 17, 1978.
73
-------
27. Anon., Zoning Ordinance, Town of Vail, Colorado, adopted
, revised.
28. Anon., Zorftng Resolution - Eagle Councy Colorado, adopced
September 16, 1974, revised.
29. Anon., Eagle County Colorado Subdivision Regulations, adopted
June 24, 1976.
30. Anon., "An Interim Guide for Erosion and Sediment Control in
Urbanizing Areas of Colorado," U.S. Department of Agriculture
Soil Conservation Service, Denver, Colorado, undated.
31. Anon., "Standards and Specifications for Soil Erosion and
Sediment Control in Developing Areas," Water Resources Adminis-
tration, Maryland Department of Natural Resources, Maryland
Department of Agriculture, College Park., Maryland, July 1975
32. Anon., "Control of Sediments Resulting from Highway Construc-
tion and Land Development," U.S. EPA Office of Water Programs,
Washington, D.C., September, 1971.
33. Anon., "Handbook of Best Management Practices," Council of Bay
Area Resource Conservation Districts, Concord, California,
October, 1977.
34. Anon., "Study of Storm Water Quality Management - Urbanized
Areas of Anchorage, Alaska," prepared by Woodward-Clyde Con-
sultants for the Department of the Army, Alaska District, Corps
of Engineers, September, 1978.
35. Anon., "Tahoe Regional Planning Agency Land Use Ordinance,
Ordinance No. 4," Revised June 29, 19 78.
36. Anon., "Grading Ordinance - An Ordinance Establishing Minimum
Standards and Providing Regulations for the Construction and
Maintenance of Land Fills, Excavations, Cuts and Clearing of
Vegetation; Providing for the Revegetation of Cleared Areas;
and Providing for Other Matters Properly Pertaining Thereto,"
Tahoe Regional Planning Agency, Ordinance No. 16, aaopted
February 10, 1972.
37. Anon., Taggart, W. C., McLaughlin, R. C., "Runoff Management
Plan - Snowmass at Aspen," prepared by Wright-McLaughlin En-
gineers for Snowmass Corporation, Benedict Land & Cattle Co.,
February, 1975.
38. Anon., "Draft Water Quality Management Plan, 208 Plan," prepared
by the Municipality of Anchorage, Alaska, with the assistance of
the Alaska District, U.S. Army Corps of Engineers, November, 1978.
39. Anon., "Lake Tahoe Basin Water Quality Management Plan," Volume
2 - Handbook of 3est Management Practices, Tahoe Regional Planning
Agency, January 1978.
40. Anon. "Subdivision Ordinance", Tahoe Regional Planning Agency
Ordinance November 7, adopted March 22, 1972.
74
-------
APPENDIX A
WATER QUALITY DATA
75
-------
UI'PER liACI.li VAI.LIiY
Station
Alr/Wacer
pit
CO l id .
DO
flow
r-Pb
Number
DuLti
Hour a
Teui|) (C*)
s.u.
Uiulioa/cm
u>8/l
1/bui.
Pg/l
CC-l
J/B
1015
2/4
a. l
67
10.3
<5
3/9
1030
2/0
7.a
73
10.1
<5
3/28
1030
8/3
a.4
60
10.0
5
3/29
1015
15/4
9.5
68
10
<5
3/30
1015
U/3
8.9
75
10.4
<5
4/2 7
1030
5/4
10
54
9.7
7
BCC-2
3/8
1200
J/3
a.6
iai
10.4
<5
3/9
1130
a/o
8.6
226
10.7
9
3/2»
111*
9/4
9.3
253
9.9
7
3/29
1100
15/4
9.5
249
10.2
7
3/JO
1050
15/4
9.2
237
10.2
7
4 m
1010
8/4
9.5
56
10.0
15
CC-3
3/U
1300
a/2
a.a
141
10.6
<5
1/9
1230
9/0
a.2
158
10.4
<5
cr>
3/28
1145
9/4
9.4<
226
9.2
<5
3/29
1130
11/4
9.4
20)
10.0
7
3/30
1130
14/4
-
175
9.9
5
4/27
1115
5/3
-
125
10.2
6
Cu-5
3/29
1325
19/4
8.7
246
a.6
13
3/JO
1105
lb/8
7.9
-
-
19
CC-6
3/U
1400
7/4
a.u
215
9.6
<5
3/9
1 JJO
7/5
7.8
215
9.9
<5
1/28
1230
10/6
9.4
2J9
9.6
<5
J/29 .
1210
15/6
9.4
215
10.0
5
3/29
1340
19/9
9.2
194
8.9
-
3/JO
1129
15/6
a.i
158
-
5
3/10
1200
14/4
a.9
201
9.1
5
4/2 7
1145
5/3
-
107
9.5
11
Cu-7 NtC
3/U
1455
7/5
a
572
-
0.090
2250
bt
3/9
1320
7/10
7.0
264
7.7
0.126
1J40
i»U
3/28
1234
15/0
8.4
114
7.8
0.063
160
NU
3/29
1140
16/9
7.0
150
9.0
140
NU
3/ 10
1147
15/9
a.5
132
-
100
Cu-8
J/b
14 JO
7/b
a
264
7.9
3.78
180
3/9
11 JO
4/9
6.9
308
8.4
1.89
140
3/28
1105
16/9
a.2
308
4.3
56
3/29
1125
1J/I0
a.a
308
7.0
90
3/30
1 2 JO
16/11
u.o
3J4
-
220
4/27
1120
a/a
a.5
JJ9
5.7
115
¦:k quality data - makcii, anul, 1978
l-Cd IOC UODi 1SS TUS NO^'NOj Nllj-N 1KN 1-K 06C Col Iformu (100 mlf T-N
Mg/1 mg/1 rag/l wg/l ug/l og/1 wg/l wg/l uig/1 Wb/1 Total Iccal u>g/l
_
1.5
0.7
0.8
62
0.16
0.06
<0.02
<0.005
<1
2
<2
<0.18
_
2.5
0.4
0.4
58
0.16
<0.01
<0.02
<0.005
-
6
<2
<0.18
5.1
0.4
4.4
52
0.15
<0.01
<0.05
<0.005
-
11
<2
<0.2
5.7
0.4
3.2
62
0.1)
<0.01
<0.05
<0.005
-
17
<2
<0.18
_
S.tt
4.0
46
0.14
<0.01
0.11
<0.005
-
-
-
0.25
<5
1.1
0.2
2.4
42
0.07
<0.01
0.11
<0.005
-
6
<2
0.18
1.6
0.7
4.6
160
0.19
<0.01
<0.02
0.006
-
2
<2
<0.21
4.6
0.6
10
218
0.24
<0.01
0.02
0.010
-
18
<2
0.26
_
25
0.8
20
196
1.03
<0.01
O.li
0.020
-
44
<2
1.16
_
22
0.7
19
198
1.08
<0.01
0.16
0.015
-
68
<2
1.24
_
17
-
22
188
1.11
<0.01
0.25
0.017
-
-
-
1.36
<5
21
0.4
19
114
0.67
<0.01
0.24
0.014
-
52
<2
0.91
_
6.6
0.6
7.8
118
0.20
<0.01
<0.02
<0.005
-
4
<2
<0.22
_
6.1
0.6
14
1J 2
0.22
<0 01
0.15
0.005
-
22
<2
0.37
_
15
0.8
10
146
0.71
<0.01
0.08
0.010
-
25
<1
0.79
-
16
0.7
10
136
0.71
<0 01
0.21
0.014
-
17
<2
0.92
_
11
-
13
114
0.67
<0.01
0.30
0.015
-
44
<2
0 92
14
11
0.4
15
80
0.37
<0.01
' 0.26
0.016
-
30
<2
0.63
_
26
1.3
28
186
0.75
0.04
0.34
0.087
2.8
100
<2
1.09
-
49
-
39
324
1.95
0.05
0.39
0.055
1.2
78
<2
2.34
_
0.5
2.6
126
0 19
<0.01
<0.02
<0.005
<1
<4
<0.21
_
2.6
0.4
6.8
132
0.21
<0.01
<0.02
0.006
-
8
<2
<0.23
20
2.0
6.8
136
0.52
0.31
0.80
0.095
-
3600
200
1.J2
20
1.6
5.6
130
0.55
0.24
0.66
0.073
-
4100
88
1.21
_
18
1.8
9.4
134
0.54
0.18
0.44
0.070
-
800
50
0.98
_
15
-
10
114
0.56
0.19
0.56
0.075
-
-
-
1.12
_
13
_
14
130
0.58
0.25
1.14
0.105
-
-
-
1.72
6
19
0.7
104
96
0.30
0.01
0.70
0.111
1.8
330
2
1.00
-
J9
>13
3220
3610
0 35
0.06
13.5
0.093
48.9
170*
21*
1J.85
-
103
> 6
1990
2310
0.29
0.06
11.0
0.135
-
iJO*
33*
11.29
-
16
11
134
222
0 21
0.19
1.08
0.120
-
23*
< 2
1.29
-
6.0
4.3
37a
492
0.15
0.12
1.65
0.130
-
3500*
< 2
l.B
-
a.7
-
214
224
0.13
0.10
1.12
0.090
-
2400*
< 2
1.25
-
22
7.9
170
J46
0.72
0.15
1.9
0.820
7.4
1600
4
2.62
-
15
5.1
186
384
0.86
0.02
1.1
0.061
-
1100*
5*
1.96
-
35
7.0
36
228
0.88
0.16
0.90
0.300
-
140
<4
1.78
-
28
>6.5
161
282
1.62
0.15
1.79
0.700
-
180
3
3.41
-
24
-
198
352
0.63
0.17
1.26
0.440
-
-
-
1.89
6
J7
17
180
156
0 73
0.26
3.5
1.44
5.1
9500
8
4.23
-------
UPPliK KACI.Ii VAI.LIiY WATER QUALITY DATA - MAKCII, Al'KIL, 1978
(Continued)
Station
Alr/Uuter
I'M
Co ltd.
IX)
now
T-Pb
T-Cd
IOC
HOD5
TSS
TDS N02
'NOj
Nllj-N
Nuutbcf
Date
Hours
Temp (C#)
S.U.
timlios/ca
rag/ I
1/eec
Mg/1
Mg/1
mg/1
mg/1
mg/1 1
mg/1 mg/1
mg/1
Cu-9
J/8
13,5
2/5
7.7
194
7.4
3.78
700
20
>12
1010
1160
0.22
0.71
3/9
1145
8/2
7.0
194
11.3
620
-
43
> 7
1215
1450
0.25
0.38
3/2B
1120
12/7
8.3
132
8.0
250
-
19
19
510
690
0.26
0.27
3/29
1105
15/7
12.4
123
5.0
290
-
4.0
14
294
360
0.11
0.45
3/30
1253
-
8.1
114
-
180
-
9.1
-
230
302
0.08
0.19
4/27
1 JOO
8/6
8.6
20J
5.5
1450
8
1.6
31
620
156
0.34
0.27
Cu-10
3/8
1315
J/2
7.7
264
8.7
3.78
240
-
-
10
506
710
0.14
0.13
3/9
1215
6/2
7.0
264
9.3
3.78
240
-
18
>7
468
618
0.16
0.14
3/28
1140
10/5
8.7
176
8 0
200
-
19
5.9
212
334
0.22
0.35
J/29
1 J40
13/6
6.2
141
9.3
K
130
-
15
6.9
179
310
0.30
0. 32
J/JO
1317
10/9
8.0
-
-
1.89
60
-
11
-
218
284
0.15
0.21
4/27
1320
8/4
-
339
7.5
17
<5
51
1.0
50
120
0.11
0.01
^JCC-11
3/8
1017
-5/0
8.8
205
-
4
-
3.0
1.3
1.6
212
0.31
<0.005
3/B
1245
-2/2.5
8.7
238
8.4
<5
-
5.1
0.9
9.8
240
0.18
<0.01
3/9
1840
J/0
7.0
308
10.4
<5
-
2.4
1.4
6.8
242
0.20
<0.01
J/9
1345
8/4
7.0
264
10.3
10
-
7.7
1.4
28
248
0.15
<0.01
3/28
1015
8/2
8.4
220
9.4
10
-
24
1.5
12
18U
0.45
0.01
3/29
1360
10/7
7.9
229
10.0
7
-
21
0.6
12
168
0.53
<0.01
3/30
135 J
10/9
8.5
-
-
9
-
19
1. 3
15
148
0.54
0 14
4/27
1115
10/5
T
147
8.0
10
<5
11
0. 9
62
110
0.33
<0.01
SIP-llA
3/8
164 5
7/10
7.2
616
5 5
5
-
1J
20
30
398
4.56
6.51
3/9
1100
0/10
6.8
616
7.0
26.3
<5
-
40
23
76
414
4.72
9.60
3/28
10J5
14/12
7.7
528
5.9
5
-
19
16
46
380
4.40
7.60
3/29
1 2 JO
16/13
7.8
572
7
9
-
9.5
49
100
394
3.20
9.20
3/30
1415
20/16
7.6
616
-
11
-
14
J7
6J
370
3.80
7 00
4/27
1020
10/10
7.7
565
4.0
10
-
7.6
4.1
11
288
2.40
0.14
CC-12
3/8
1215
-2/2
9.0
308
7.3
-
5
-
5.1
2.3
14
272
0.41
0.48
3/9
1025
3/0
7.0
352
9.4
-
<5
-
5.3
3.3
13
268
0.60
0 60
3/28
1000
8/2
8.6
194
10.0
-
18
-
22
2.3
12
184
0 56
0.15
J/29
124 5
10/7
8.9
251
9 5
-
<5
-
19
3.1
12
178
0.58
0.22
3/JO
1 J40
10/9
8.5
229
-
-
5
-
19
2.9
12
160
0.60
0.25
4/27
1000
10/5
7.9
1 2 J
8.0
-
9
<5
9.9
1.4
48
116
0.34
<0.01
C.i-13
J/8
1525
7/4
8.2
2J8
8.9
7.57
400
-
20
14
780
996
0.30
0.08
3/9
1300
7/2
7.0
264
7.1
11. «1»
560
-
23
>7
1580
1620
0.41
0.05
3/28
1315
15/12
7.1
81
6.7
-
23o
-
12
2.6
lu50
1090
0.24
0.11
3/29
1005
12/10
8.6
194
7.5
-
80
-
11
3.3
184
318
0.39
0.12
3/JO
1126
28/15
7.9
109
2.0
-
120
-
8.0
-
448
550
0.29
0.20
4/27
1220
5/8
7.8
282
7.4
-
170
6
44
39
210
216
0.78
0.35
1KN t-r OfcG Col1forms(100 mlf T-N
mg/1 mg/1 Bg/i Total Fecal mg/1
9.8
6.4
3.76
2.0i
1.41
6.0
2.8
2.8
2.21
1.50
1.40
0.60
5.76
2.68
0.500
0.400
0.240
0.95
0.180
0.156
0.215
0.154
0.140
0.072
0.20 <0.005
0.17
<0.02
0.34
0.20
0.39
0.81
0.45
9.15
16.9
14.1
17.7
14.5
0.016
0.010
0.018
0.030
0.022
0.060
0.062
3. J4
3.62
4.30
6.10
5 84
1.25 1.58
0.85
1.3
0.46
0.54
0.98
0.42
3.1
3.4
4.45
1.28
3.41
3.7
34.1
13 5
11.4
17.8
19.4
9.2
3.4
<1
1
1300*
3300*
24000*
24 000*
9200*
2100*
1300*
490*
7900*
9200*
5400*
170*
670
24
80
220
1200
490
660
520
4900O*
79000*
13000*
54000*
79000*
0 183
0.220
0 135
0.165
0.140
0.062
0.117
0.169
0.200
0.110
0.200
0.284
17.7
44.1
740
3960
1700
4100
3600
2 50
49*
13*
8*
8*
<2*
<2*
4*
<2*
79*
230*
130*
<2
20
<2
8
a
76
15
22
<4
10.02
6.65
4 .02
2.16
1.51
6.34
2.98
2.96
2.45
1.80
1.55
0.91
0.53
0.35
0.22
0.49
0.65
0.91
1.35
0. 78
11000* 13.71
14000* 21.62
70O*
24000*
18.5
20.9
2800* 18.3
54000* 17000* 3.65
8
28
70
22
53
10
33*
7900*
7900* 13*
- 160000* 16O00O*
1.5 -
5.8 24000* <2«
11.4 24000* 2*
1.26
1.9
1.02
1.12
1.58
0.76
3.4
3.81
4.69
1.67
3.7
4.18
-------
UlU'EK EAGLE VALL1£Y WATEK QUALITY DATA - MARCH, AI'RIL, 1978
(Continued)
Stdtlau
Numbei
Dace
Hour a
Alr/Ualor
Temp (C*)
pU
S.U.
Cond.
Iimtioa/co
U0
og/1
Flow
1/aec
T-Pb
lig/1
T-Cd
Pg/1
T0C
mg/1
B0Ds
mg/1
TSS
ng/1
TDS N02»NOa
mg/1 mg/1
Nllj-N
mg/1
TKH
ng/1
T-P OLG
mg/1 «*/!
Col 1 forma (100 ulf T-N
Total Fecal mg/1
CC-14
3/8
1030
-1/0
8.6
351
11.1
<5
_
8.1
12
33
306
0.60
0.11
3.0
1.00
<1
12000
170
3.6
3/9
1220
10/3
6.7
352
10.5
-
<5
-
6.0
4.0
16
282
0.77
0.14
1.1
0.320
-
1600
8
1.81
3/28
1330
14/8
B.O
301
9.6
-
6
-
26
3.2
19
230
0.69
0.13
0.87
0.305
-
830
9
1.56
3 /29
1235
12/6
7.8
273
9.5
-
1
_
22
4.1
26
212
0.74
0.14
0.87
0.235
-
2600
13
1.51
3/J0
1055
14/5
8.3
246
10.0
-
7
-
21
-
12
176
0.71
0.0J
0.39
0.157
-
-
-
1.10
4/27
1235
5/6
7.8
192
7.3
-
14
6
4.0
2.8
100
126
0.36
0.02
0.96
0.260
""
560
130
1.32
fcb-15
3/tt
1200
5/0
7.5
3J3
10.2
_
10
_
5.4
1.4
9.6
266
0.14
0.04
0.34
0.005
<1
96
2
o.4a
3/0
1025
5/0
8.2
334
10.5
-
20
-
4.5
1.2
6.5
268
0.15
0.05
0. 3J
0.013
~
60
18
0.48
3/28
1255
14/6
8.0
306
10.1
-
15
-
8.9
3.8
19
254
0.22
0.02
0. 32
0.025
-
<2
<2
0.54
3/29
1135
12/4
7.6
316
10.5
-
17
-
8.0
1.0
21
254
0.22
0.04
0.42
<0.005
<2
<2
0.64
3/JO
1200
15/5
7.7
308
10.2
-
19
-
7.7
-
27
248
0.23
0.04
0.46
0.025
~
~
~
0.69
Cu-16
3/9
1155
J/2
tt.l
123
9.3
0.631
500
_
27
>7
885
662
0.22
0.08
2.6
0.141
12.
5 170*
<2*
2.82
3/28
1120
12/3
7.8
aa
9.6
0.378
120
-
2.2
2.2
78
178
0.89
0.18
1.13
0.145
1.
5 2300*
3 J*
2.02
3/29
1105
13/2
7.6
53
11.0
0.421
60
-
2.0
1.0
48
134
0.42
0.12
0.85
0.106
2 79*
<2*
1.27
3/JO
12 30
13/2
8
70
11.3
0.505
24
-
4.0
-
24
98
0.31
0.11
0.63
0.105
-
-
0.94
EK-17
3/tt
1230
2/4
8.2
317
9.8
15
J.O
0.6
7.4
238
0.17
0.02
0.26
<0.005
<1
16
<4
0.43
3/9
1055
8/2
8.2
308
10.1
-
25
-
10
1.6
8.4
246
0.17
0.04
0.25
0.018
-
24
4
0.42
3/28
1055
10/4
8.1
356
10.0
-
16
-
12
0 6
18
240
0.26
0.02
0.35
0.017
-
4
<2
0.61
3/29
1040
10/4
7.9
317
10.5
-
21
-
8.0
0.6
22
258
0.27
0.01
0.27
0.047
-
<2
<2
0.54
3/JO
1410
20/-
7.6
304
9.5
-
47
-
9.0
-
26
244
0.27
0.02
0.45
0.025
—
-
""
0.72
tK-18
3/9 \
1125
10/1
8.3
290
10.7
_
15
_
6.1
1.5
8.4
234
0.34
0.07
0.52
0.103
<1
160
4
0.86
3/28'
1020
13/2
tt.9
J26
10.0
-
10
-
-
0.9
15
216
0.40
0.05
0.46
0.070
<1
170
10
0.86
3/29
1015
10/2
8.3
301
10.0
-
18
-
14
1.0
16
230
0.44
0.04
0.35
0.095
—
350
19
0. 79
3/30
1J4 5
16/7
7.9
297
9.5
-
13
-
10
-
19
218
0.46
0.03
0.39
0.077
83
8
0.85
a. HaicerJal uiuly^lb by Hllllpure Filtration except. when * Id shown, then by Hoai Piobable Number metltocj.
b. Flow 6bC ln«t(c,
c. Ulidccions refer to four culveiiu at sampling point CC-7.
The baui|tlc*d obtained Apt 11 27, 1^78 were aiao aitulyzed for toLal uelenlum. All concentrations were below
the detect lou llali of the anaiyulu method uaed. 10 |ig/t.
-------
GORE CREEK, BIOCHEMICAL OXYGEN DEMAND
12 oig/l
-MARCH I
MARCH 29
MARCH 28
MARCH 30
APRIL 21
OC-II
6C-12
ac-H
OC-I
6C-3
GC-S
STATION
-------
GORE CREEK, NITRATE PLUS NITRITE
STATION
-------
GORE CREEK, AMMONIA-NITROGEN
I 0
o e
o a
o i
5. 0 8
3E
> 0 t>
Z
+
JP 0 4
z
0 3
0 2
0 I
i—i—i i i i i i i r
MARCH 0. 26. 20. 30
\
GC-3
MARCH 8
MAR 29
GC-B GC-II
STATION
GC-12
6C-I4
NOI€ LIMIIED NHj - HH^~ 0*1* WERE *V*ll*BLE FROM (HE *PRIL 27 S*MPLINQ RUN THESE 0*1* INOIC*IED MO INCREASE IN CONCENIRM ION EXCEPT
FOR STATIOH OC-M >H ICH INCRE*SEP FROM 0 01 «ig/l 10 0 02 ag/l FOR THIS RE*SON. 1HESE DAT* WERE NOT PLOTTED
-------
0
1
CO
CI
n
GORE CREEK, TOTAL PHOSPHORUS
5
MARCH
4
3
/s
'// ~
<—/—MARCH 29
7
MARCH 30
MARCH 26
APRIL 27
o
BC-14
ac-e
fiC-l I
OC-12
ec-i
6C-3
STATION
-------
GORE CREEK, TOTAL LEAD
MARCH
APRIL 27
/ MARCH 30
MARCH
MARCH 29
MARCH 8
GC-I GC-3 GC-8 QC-II 6C-I2 GC-14
STATION
-------
GORE CREEK. TOTAL SUSPENDED SOLIDS
100
CO
o
Z3
MARCH 30
I I I I I I
APRIL 21
MARCH 8
MARCH 20
MARCH 28
MARCH 0
GC-I
GC-3
GC-8
QC-II
GC-I 2
GC-I 4
STATION
-------
£T>
I
CO
C~i
GORE CREEK, TOTAL DISSOLVED SOLIDS
MARCH 8 (306 rag/1)
MARCH
MARCH 28
200
MARCH 29
MARCH 30
ISO
APRIL 21
100
so
60-14
GC-12
GC-I I
QC-3
GC-I
STATION
-------
GORE CREEK AT VAIL
TOTAL DISSOLVED SOLIDS AND FLOW, OCTOBER 1974 TO SEPTEMBER 1975
400
200
iao
300
ISO
MO
170
240
100
200
TOS
80
160
80
120
00
20
40
J
FLOW
OCf NOV DEC t AH ft# MAR APR HAY iUN IUI A 00 SEP
1974 —«-{-•— 18)5
MONTHS
-------
BLACK GORE CREEK NEAR VAIL
TOTAL DISSOLVED SOLIDS AND FLOW, OCTOBER 1974 TO SEPTEMBER 1975
zoo
250
180
iao
200
MO
I 20
ISO
TOS
100
so
100
eo
40
FLOW
I —| 1 1
oci
NOV
OfC
FEB
MAR
HAY
IUN
1974 —j-i— I 9)5
MONTHS
-------
APPENDIX 3
EXAMPLE GRADING ORDINANCE
33
-------
APPENDIX B
EXAMPLE GRADING ORDINANCE
Section 1.00 Findings
The County Board of Commissioner3/Town Council finds that in order
to effectuate the adopted Areawide Water Quality Plan prepared by
the Northwest Colorado Council of Governments and to protect the
water quality of the streams flowing through the County/Town and
their beneficial uses, it is necessary to adopt this ordinance
establishing minimum standards and providing regulations for the
construction and maintenance of landfills, excavations, cuts and
clearing of vegetation, providing for revegetation of cleared
areas, and providing for other matters properly relating thereto.
Section 2.00 General Provisions
2.10 Compliance
Construction and maintenance of any Landfills, excavations
and cuts and clearing of vegetation and the revegetation
of cleared areas shall be in compliance with the terms of
this Ordinance. Permits shall be required as provided in
this Ordinance, and such permits shall be granted or de-
nied in conformity with the provisions of this Ordinance.
2.20 Interpretation and Severability
The provisions of this Ordinance shall be liberally con-
strued to effectuate their purposes. If any section,
clause, provision or portion of this Ordinance is adjudged
unconstitutional or invalid by a court of competent juris-
diction, the remainder of this Ordinance shall not be
affected thereby.
2.30 Short Title
This Ordinance may be cited and referred to as the
"Grading Ordinance."
Section 3.00 Definitions
For the purposes of this Ordinance, certain terms or words used
therein shall be interpreted as follows: Words in the present
tense include the future; words in the singular number include
the plural number, and words in the plural number include the
singular number. The word "shall" is mandatory, not permissive,
unless the context indicates that a directory meaning is intended.
Accelerated Erosion - The removal of the surface of Che land
through the combined action of man's activities and the
89
-------
natural processes at a rate greater than would occur
because of the natural process alone.
Area of Instability - An area where there is a foreseeable risk of
soil or rock movement.
Clearing of Vegetation - Total or partial removal of naturally
occurring vegetation on an area of land.
County - Eagle County.
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.
Earth-moving Activity - Any construction or other activity which
disturbs the surface of the land including, but not
limited to, excavations, embankments, Land development,
subdivision development, mineral extraction and the
moving, depositing or storing of soil, rock or earth.
Embankment or Fill - A deposit of soil, rock, or other material
placed by man.
Erosion - The natural process by which the surface of the land is
worn away by the action of water, wind or chemical action.
Excavation - A cavity formed by digging, quarrying, uncovering,
displacing, or relocating soil or rock.
Flood Plain - Areas adjoining a water course, lake or other body
of water that have been or may be covered by flood waters.
Flood Water - Waters from water courses or bodies of water chat
temporarily Inundate the land in flood plains¦
Fill - Any rock, soil, gravel, sand, or other material deposited
by man.
Grading - Cutting through or otherwise disturbing the layers of
the soil mantle so as to permanently change the existing
Landform.
Person - An individual, partnership, corporation, business asso-
ciation, or group of individuals, and any governmental
entity.
Sediment - Soils or other materials transported by surface water
as a product of erosion.
Sedimentation - The process by which sediment is deposited on
stream bottoms.
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Stabilization - The proper placing, grading and/or covering of
soil, rock or earth to insure their resistance to erosion,
sliding, or other movement•
Surface Water - Waters falling upon, arising from the naturally
spreading over lands and produced by rainfall, melting
snov or springs•
Town - Town of Vail/Minturn.
Water Course - A running stream of water; a natural stream, in-
eluding rivers, creeks, runs and riverlets. It may some-
times be dry but must flotf in a definite channel.
Section 4.00 Permit Procedure
4.10 When Required
No person shall commence or perform any grading or filling
or clearing of vegetation without having first obtained a
permit from the County/Town.
4.11 Exceptions
All other applicable provisions of this section shall
apply, but a permit shall not be required if the work
complies with any of the following conditions:
(1) The excavation does aot exceed four (4) feet in ver-
tical depth at its deepest point measured from che
original surface and does not exceed 200 square feet
in area.
(2) The fill does not exceed three (3) feet in vertical
depth at its deepest point measured from the natural
ground surface and the fill material does aoc cover
more than 200 square feet.
(3) Exploratory excavations not to exceed an aggregate
area of 200 square feet.
(4) An excavation below finished grade for basements and
footings of a building authorized by a valid building
permit. This excavation does not affect the require-
ment of a grading permit for any fill made with Che
material from such excavation.
(5) Clearing of vegetation which does not exceed 1,000
square feet in area on slopes less than 30 percent.
(6) Work by a public agency in accordance with plans
approved by the Agency.
(7) The water quality impact analysis of an Environmental
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Impact Report demonstrates to the satisfaction of the
Environmental Health Officer of the County/Town that
the proposed grading, filling, excavations and clear-
ing of vegetation performed in accordance with any
other permit, condition or entitlement in accordance
with EIR-recommended mitigation measures Issued by
the County/Town will not result in the degradation of
a water course or its beneficial use.
4.12 Even though an activity is not required to obtain a
permit under the exceptions described herein, the person
undertaking the activity shall comply with the other
provisions of the Ordinance.
4.20 Application
4.21 Applications required by this Ordinance shall include an
Information Report, a Grading Plan and a Restabilization
and Revegetation Plan as herein described or as required
by Sections 6.00 and 7.00 of this Ordinance.
4.22 Information Report
Applicants for a grading permit pursuant to the provisions
of this ordinance shall furnish an Information Report pre-
pared by a person or firm qualified by training and ex-
perience to have expert knowledge of the subject. The
County/Town shall determine the adequacy of the report and
may require the submission of further information where
necessary. The information required supplements and/or
replaces the information required by the County/Town
Zoning Ordinance and Subdivision Regulations. The report
shall provide information as follows, except to the extent
that the County/Town determine that such information is
not applicable to the project.
(1) A statement of the land capabilities of the property
on which the grading is to be performed, including
soil name, soil group, hydrologic group, slope, run-
off potential, soil depth, erosion potential, and
natural drainage.
(2) A statement of the credentials of the person or
persons who drew up the plans and made the certifi-
cations required by this ordinance.
(3) Accurate contours at two (2) foot intervals for
slopes up to 15 percent and five (5) foot intervals
for slopes over 15 percent showing the topography of
the ground to be graded and filled or cleared and the
topography of the fifteen (15) feet adjacent to such
area ¦
(4) A subsurface soil and geological report including
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subsurface investigations, as may be required in
Section 5.00 of this ordinance.
(5) An accurate plot plan showing the exterior boundaries
of the property on which the grading is to be per-
formed.
(6) Elevations, dimensions, including quantity, location,
and extent of proposed grading.
4.30 Application Review
4.31 Any person proposing to perform grading, filli'ng or
clearing of vegetation requiring a permit as herein de-
scribed shall submit an Information Report, Grading Plan
and Revegetation Plan as required by Sections 4.20, 6.00,
and 7.00 at least thirty (30) days prior to the regularly
scheduled meeting of the Planning Commission at which the
applicant wishes to be heard.
4.32 The Planning Commission may defer the hearing of the
application for a Grading Permit upon recommendation of
the Planning Commission staff or the Environmental Health
Officer of the County/Town that the application for a
permit for proposed grading, filling or clearing of vege-
tation should be reviewed by other governmental agencies
wherein the quality or beneficial uses of water courses
within the affected jurisdictions may be adversely
affected.
4.33 The application for a Grading Permit is for an activity
governed by the County/Town Zoning Ordinance or Subdi-
vision Regulation, Planning Commission review will be in
accordance with those regulations and ordinances.
Section 5.00 Required Additional Investigations and Reports
5.10 General Requirements of Subsurface Investigations
For the purposes of preparing the soil and geological
report, subsurface investigations shall be performed
throughout the area to sufficiently describe the existing
conditions.
5.20 Specific Requirements of Subsurface Investigations
In particular, subsurface investigations shall be con-
ducted where stability will be lessened by proposed
grading or filling or where any of the following con-
ditions are discovered or proposed:
(1) At fault zones where past land movement is evident.
(2) At zones of crapped water or high water table.
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(3) At historic landslides or where che topography is
indicative of historic landslides.
(4) At adversely sloped bedding planes, short-range
folding, overturned folds, and other geologic
formations of similar importance.
(5) At locations where a fill slope is to be placed above
a cut slope.
(6) At proposed cuts exceeding twenty (20) feet in
height, unless in extremely competent rock.
(7) Locations of proposed fills exceeding twenty (20)
feet in height.
(8) Where side hill fills are to be placed on existing
slopes steeper than fifteen (15) percent.
(9) Wherever groundwater from either the grading project
or adjoining properties is likely to substantially
reduce the subsurface stability.
Where any of the particular problem areas listed above or
other weaknesses are found, the subsurface investigation
shall be of sufficient intensity to describe che problem
thoroughly. The person or firm making che report shall
3ubmit a written report of their findings and recommenda-
tions •
Section 6.00 Grading Plan
6 .10 Plan Required
The applicant shall submit a grading plan which shall
demonstrate chac che proposed grading and filling acti-
vities will noc cause surface runoff from che sice Co
exceed the water quality criteria of che Councy/Town.
Such plan shall be certified by a person or firm
qualified, as determined by the County/Town, in che
subjeccs of erosion and sedimentation control. The
Grading Plan shall include as a minimum che following
information:
(1) A description of equipment and methods to be employed
in processing and disposing of soil and other mater-
ial chac is removed from che grading sice, including
che location of disposal sices.
(2) A map showing che locacion and type of all erosion
control and drainage measures, or other protective
devices to be constructed in connection with, or as a
part of, che proposed work, cogecher with a aap
showing che drainage area and estimated runoff of che
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area served by any drains and proposed method of
runoff disposal.
(3) A schedule showing when each scage of the project
will be completed, including estimated starting and
completion dates, hours of operation, and days and
weeks of operation.
(4) A soil stabilization report including final ground
cover, landscaping, and erosion control, and re-
quirements for 3table cut and fill slopes based upon
stability analysis.
(5) A signed certification by a person qualified by
training or experience to prepare such plans that the
water quality criteria of the County/Town will noc be
exceeded.
Section 7.00 Revegetation and Slope Stabilization
7.10 Plan Required
The applicant shall submit a slope stabilization and
revegetation plan which shall include a complete descrip-
tion of the existing vegetation, the vegetation to be re-
moved and its disposal, the vegetation to be planted, and
slope stabilization measures to be installed.
7.20 Submittal of Plan
The revegetation and slope stabilization plan shall be
submitted with the grading plan unless the revegetation
plan is a part of an application for clearing of vegeta-
tion which doe3 not include or contemplate grading or
filling.
Section 8.00 Inspections
8<10 Inspection at Reasonable Times
All construction or work for which a permit is required
shall be subject to inspection at reasonable times by
authorized employees of the permit-issuing authority or
agency.
8.20 General Inspections
The permit-issuing authority or agency may make any in-
spections of any construction work deemed necessary to
ascertain compliance with the provisions of this ordinance
and other ordinances which the permit-issuing authority or
agency enforces.
8.30 Notification
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The permittee or his agent shall notify the permit-issuing
authority at least two (2) working days in advance of the
start of the grading operation.
8.40 Changed Conditions
If the inspector finds the soil or other conditions other
than as stated in the application for a grding permit, he
may refuse to approve further work until approval is ob-
tained for a revised garding plan which will conform to
the existing conditions-
8.50 Inspection of Concealed Work
Whenever any work on which inspections are required by
this Ordinance is covered or concealed by additional work
without first having been inspected, the permit-issuing
authority may require, by written notice, that such work
be exposed for examination. The work of exposing and
recovering shall not entail expense to the permit-issuing
authority.
Section 9.00 Standards of Grading, Filling and Clearing
9.10 Permit Duration
9.11 Time Limit
All grading, filling, clearing of vegetation, or other
disturbance of the soil shall be completed by September
15.
9.12 Extension
An extension of the permit may be granted upon a showing
by the permittee that the work was delayed by reasons be-
yond his control or that an extension will not increase
the risk of environmental damage caused by the grading,
filling or clearing of vegetation.
9.20 General Criteria for Grading, Filling and Clearing
Operations
All grading, filling, and clearing operations, whether or
not a permit is required under this Ordinance, shall be
designed
(1) To preserve, match or blend witn the natural contours
and undulations of the land.
(2) To retain trees and other native vegetation, to sta-
bilize hillsides, retain moisture, reduce erosion,
silcation and nutrient runoff and preserve the
natural scenic beauty.
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(3) To minimize scars from cues and fills.
(4) To reduce Che amount of cues and fills and to round
off sharp angles ae the top and coe and sides of all
necessary cue and fill slopes.
(5) To limit development on steep or hazardous terrain.
(6) To take into consideration geologic hazards and
adverse soil conditions and their effect on the
fucure stability of the development.
(7) So that all cleared slopes, including ski slopes,
cuts and fills and other areas vulnerable to erosion
3hall be stabilized.
(8) So that construction, clearing of vegetation, or dis
turbances of the soil be limited to those areas of
proven stability.
(9) So that the natural geologic erosion of hillsides,
slopes, graded areas, cleared area, filled areas or
streambanks will not be exceeded.
9.30 Discharge Prohibitions (manmade)
9.31 Direct Discharge
No solid or liquid waste materials including soil, silt,
clay, sand, and other organic or earthen materials shall
be discharged into the Eagle River or any of its tribu-
taries or onto lands within the 100-year flood plain of
any tributary.
9.32 Mo material shall be placed within the 100-year flood
plain of any tributaries to the Eagle River or in any
other location from which it would be susceptible to
erosion and/or deposition into said waters.
9 .33 Temporary Control
Approved temporary erosion and sedimentation control de-
vices, facilities and measures shall be required during
construction.
9.40 Dust Control
Whenever the native ground cover is removed or disturbed,
or whenever fill material is placed on the site, the
exposed surface shall be treated to the extent necessary
to eliminate dust arising from che exposed material. Dust
control methods must be approved by the permit-issuing
authority.
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9.50 Weather Conditions
9.51 Seasonal Prohibition on Grading
Grading and filling shall be prohibited daring the period
from September 15 through May 15, excepc as otherwise pro-
vided by this ordinance.
9.60 Scheduling of Operations
All grading and filling operations shall proceed according
to a work schedule included in the grading plan. The
schedule shall be drawn up to limit to the shortest pos-
sible period of time that soil is exposed and unprotected.
9.70 Disposal of Cleared Vegetation
Vegetation removed during clearing operations shall be
disposed of by chipping all or some of the cleared vegeta-
tion and stockpiling on the site for use as mulch or com-
post, or disposal in the manner and to a location approved
by the permit-issuing authority.
9.80 Disposal of Removed Earthen Materials
Earthen materials removed during operations hereunder
shall be disposed of as follows:
(1) Stockpiling all or some of the topsoil on the site
for use on areas to be revegetated.
(2) Disposal of the earthen material at a location
approved by the County/Town.
9.90 Cuts
9.91 Maximum Slope
The maximum cut slope shall be determined on the basis of
the risk of instability or soil erodibility as shown by
the soil report and other available information.
9.92 Slope Material
If the material of the slope is of such composition and
character as to be unstable under the maximum moisture
content anticipated, the County/Town shall require such
measures as are necessary to insure the stability of the
slope. Such measures aay include, but are not limited to,
reduction of the slope angle and mechanical stabilization
of the slope.
9.93 Setbacks
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Tops of cue slopes shall noc be made nearer co a property
line Chan three (3) feet, plus one-fifth of the height of
che cut, but need not exceed a horizontal discance of cen
(10) feet. Top of any cut shall be a minimum distance of
six feet measured horizontally from any fill slope.
(1) Building foundations shall be set back from the top
of a slope a minimum distance of six feet for all cut
slopes steeper than the ratio of two horizontal to
one vertical.
(2) The setbacks given in this subsection are minimum and
may be increased if considered necessary for safety
or stability or to prevent possible damage from
water, soil, or debris.
9.94 Mechanical Stabilization
Where mechanical stabilization or containment of che slope
by other than the use of native material is employed, the
stabilization devices shall be at least partially screened
by vegetation.
9.100 Fills
9.101 Maximum Slope
The maximum fill slope shall be determined on Che basis of
the risk of instability or soil erodibility as shown by
the soil report and other available information.
9.102 Fill Material
No organic material, such as vegetation or rubbish, or any
other macarial not subject co proper compaction or other-
wise not conducive to its stability shall be permitted in
fills. No rock or similar irreducible material with a
maximum dimension greater chan eighc (8) inches shall be
buried or placed in che cop six feet of fills.
9.103 Borrowing
Borrowing for fill is prohibited unless a grading permic
has been issued cherefor.
9.104 Compaction
Each layer of aacerial for fill shall be compacted to
relative compaction of not less than 90 percent as cer-
tified by applicant to che peraic-issuing authority.
9.105 Moisture Content
Ac che cime of compaccion, che moiscure content of the
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fill material shall be such that Che specified relative
compaction may be obtained with the equipment being used.
9.106 Setbacks
The top and bottom of fill slopes shall be so located that
no portion of the fill slope will be closer than ten feet
to any adjacent property line. In addition the toes of
fill slopes shall not be nearer to any adjacent property
line than one-half the height of the fill, but need not
exceed a horizontal distance of twenty feet.
The setbacks given in this section are minimum and may be
increased if necessary for safety or stability or to pre-
vent damage from water, soil, or debris.
9.110 Interceptors
Paved or riprapped or equivalently stabilized interceptors
shall be installed at the top of all cut and filled slopes
where there is a surface runoff potential.
9.120 Erosion Control and Revesecatlon Performance 3ond
An Erosion Control and Revegetation Performance Bond shall
be posted. The amount of bond shall be the estimated cost
of the erosion control measures and revegetation as deter-
mined by the County/Town. The bond shall noc be released
until the required vegetation has survived satisfactorily
for three years. The permit-issuing authority shall
either call or release the bond not later than the end of
six years.
9.130 Plant Material Protection Methods
9.131 Restriction of Vehicles to Graded Areas
There shall be no excavation on the sice before the
perait-issuing authority has approved the location of the
stake-out of the drives, parking sites, building sices,
and other areas to be graded or filled. Construction
equipment shall be limited to the actual area to be graded
according to the approved plan3. No vehicles of any kind
shall pass over areas co be left in their natural state
according to the approved plans.
9.132 Tree Suffer Zone
No grading or operation of heavy equipment shall take
place within the area bounded by the drip line of any tree
on or off the property. This does not apply to those
trees which are within the actual construction area and
are to be removed according co the Tree Removal Plan and
the Tree Removal Permit.
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9.133
Protection Barriers
During construction the permittee shall provide appro-
priate barriers arounc. all native vegetacion proposed for
retention.
9.134 Responsibility of Contractor
The permittee shall be fully responsible for any damage
caused to existing trees or other vegetation. He shall
carry the responsibility both for his own employees and
for all subcontractors from the first day of construction
until the notice of completion if filed.
9.140 Wlnterizatlon
All exposed soil areas shall be stabilized at the earliest
possible time upon the completion of grading, filling, or
vegetation removal operations during any construction sea-
son, but no later than October 1. The County/Town may re-
quire wlnterization to be completed at an earlier time.
Section 10.00 Variances
The County/Town may grant modifications from the provisions of
this ordinance in specific instances or circumstances where,
owing to special conditions, a literal enforcement will result
in unnecessary hardship. Such action shall not be contrary to
the public interest nor the purpose of this ordinance. No
variance shall be granted if the effect will be to nullify the
objectives of this ordinance.
Section 11.00 Violation
Violation of any provision of this Ordinance is a misdemeanor.
Each day's violation shall constitute a separate offense.
Section 12 .00 Effective Date
This Ordinance shall be effective 60 days after its adoption.
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TECHNICAL REPORT DATA
fPteme read Inttrucnont on [he reverse before complennfl
1 REPORT NO 3.
EPA-908/3-80-001A
3 RECIPIENT'S ACCESSION NO
4. TITI.S ANO SUBTITLE
Upper Eagle Valley Nonpoint Source
Assessment and Control Plan
Volume 1- Assessment of Nonooint Snurr^
s report oats
February 1980
3. PERFORMING ORGANIZATION CODE
7 AUTWOAIS)
Mr Phi Hi n ,1 Mnrric
a. performing organization report no
9 PERPORMING ORGANIZATION NAME ANO AOOHSSS
Engineering - Science
125 West Huntington Drive
Arcadia, California 91006
10 PROGRAM ELEMENT NO
Final
11 CONTRACT/GRANT NO
68-01-4611
13. SPONSORING AGENCY NAME ANO ADDRESS
U.S. Environmental Protection Agency
1860 Lincoln Street
Denver, Colorado
13 TYPE OP REPORT ANO PERtOO COVEREO
14 SPONSORING AGENCY COOE
is. supplementary notes
ia abstract
The quality and quantity of water determines stream uses. A stream may be used
as a domestic water supply, to support recreation, for crop irrigation, or to main-
tain a habitat for fish or other wildlife. The quality of water in a stream deoends
upon the amount of pollutants entering the stream, and the capacity of the stream
to cleanse itself. The sources of pollutants entering a stream can be divided into
two types which are called point sources and nonpoint sources. Point sources are
facilities where a collected and controlled water supply has been used before beinq
discharged to a stream. An industrial plant is an example. Nonpoint sources are
diffuse and generally uncontrolled such as rainfall runoff or seepage from ground-
water. This study is primarily concerned with existing and potential nonpoint
sources of water pollution in the Upper Eagle Valley of Colorado.
17 KEY WORDS ANO DOCUMENT ANALYSIS
1 DESCRIPTORS
b IDENTIFIERS/OPEN ENDED TERMS
c. cosati Field/Group
Nonpoint Sources
Water Pollution Control
Water Runoff
Snowmelt
Runoff
Storm Water Drainage
SMrm Water Runoff
Upper Eagle Valley, Co.
8est Management Practices
18 OISTHI8UTIQN STATEMENT
Distribution Unlimited
19 SECURITY CLASS /Thu Rtporr}
l!nr1a«i fipri
21 NO OP PAGES
lid
30. SECURITY CLASS /Thu page)
Unclassified
11 PRICE
iPk Farm 2230-1 (Rav. 4-77) PQCvioua iOi tiOn i J o BjOUTt
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