U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2012–5214

Prepared in cooperation with Routt County, the Colorado Water Conservation Board, 

and the City of Steamboat Springs

Water-Quality Assessment and Macroinvertebrate 

Data for the Upper Yampa River Watershed, Colorado, 

1975 through 2009
COVER: Yampa River at Steamboat Springs, Colorado, looking downstream. Steamflow is an 

estimated 104 cubic feet per second.

Photograph by Nancy J. Bauch, U.S. Geological Survey, taken February 10, 2011.
Water-Quality Assessment and 

Macroinvertebrate Data for the Upper 

Yampa River Watershed, Colorado, 

1975 through 2009

By Nancy J. Bauch, Jennifer L. Moore, Keelin R. Schaffrath, and Jean A. Dupree

Prepared in cooperation with Routt County, the Colorado Water Conservation Board, 

and the City of Steamboat Springs

Scientific Investigations Report 2012–5214

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2012

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as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner.

Suggested citation:

Bauch, N.J., Moore, J.L., Schaffrath, K.R., and Dupree, J.A., 2012, Water-quality assessment and macroinvertebrate 

data for the Upper Yampa River watershed, Colorado, 1975 through 2009: U.S. Geological Survey Scientific Investigations 

Report 2012–5214, 129 p.
iii

Contents

Abstract...........................................................................................................................................................1

Introduction.....................................................................................................................................................2

Purpose and Scope ..............................................................................................................................4

Study Area..............................................................................................................................................4

Hydrology and Water Resources ..............................................................................................6

Geology..........................................................................................................................................9

Methods of Data Compilation, Review, and Analysis ..............................................................................9

Data Sources and Water-Quality Database...................................................................................11

Data Quality Assurance.....................................................................................................................11

Data Aggregation................................................................................................................................13

Censored Values .................................................................................................................................13

Water-Quality Standards...................................................................................................................16

Temporal Trend Analysis ...................................................................................................................17

Water-Quality Assessment.........................................................................................................................18

Streams.................................................................................................................................................18

Physical Properties ...................................................................................................................18

Dissolved Solids and Major Ions.............................................................................................38

Nutrients......................................................................................................................................41

Trace Elements and Uranium...................................................................................................45

Coliform Bacteria.......................................................................................................................55

Suspended Sediment ................................................................................................................55

Lakes and Reservoirs.........................................................................................................................56

Groundwater........................................................................................................................................61

Physical Properties ...................................................................................................................61

Dissolved Solids and Majors Ions...........................................................................................67

Nutrients......................................................................................................................................73

Trace Elements...........................................................................................................................76

Macroinvertebrate Data.............................................................................................................................83

Synthesis of Water-Quality Data in the Upper Yampa River Watershed............................................85

Summary........................................................................................................................................................87

Acknowledgments.......................................................................................................................................90

References Cited..........................................................................................................................................91

Appendix 1. U.S. Environmental Protection Agency STORET edit-checking procedure of 

low and high values for selected water-quality properties and constituents from 

the Upper Yampa River watershed water-quality database. ..................................................95

Appendix 2. Selected Colorado Department of Public Health and Environment in-stream 

water-quality standards for stream segments in the Upper Yampa River watershed, 

Colorado...........................................................................................................................................97

Appendix 3. Description of selected stream sampling sites in the Upper Yampa River 

watershed, Colorado, with type of water-quality data collected, period of waterquality record, and number of samples collected, 1975 through 2009.. ..............................100

Appendix 4. Description of selected lake and reservoir sampling sites in the Upper Yampa 

River watershed, Colorado, with type of water-quality data collected, period of 

water-quality record, and number of sample days, 1985 through 2009...............................110
iv

Appendix 5. Description of selected groundwater sampling sites in the Upper Yampa 

River watershed, Colorado, with geologic unit description, type of waterquality data collected, period of water-quality record, number of samples 

collected, and constituents with exceedances of Colorado Department of Public 

Health and Environment water-quality standards for groundwater, 1975 through 

1989 and 1998.... ............................................................................................................................112

Appendix 6. Description of stream sites in the Upper Yampa River watershed, Colorado, 

that have macroinvertebrate data, and period of water-quality record and number 

of sample days, 1975 through 2008............................................................................................126

Figures

1. Location of the Upper Yampa River watershed, Colorado.....................................................3

2. Land cover in the Upper Yampa River watershed, Colorado, 2001.......................................5

3. Location of selected stream-water sampling sites and active, water year 2010, 

streamgage stations, Upper Yampa River watershed, Colorado..........................................7

4. Mean monthly streamflow for 2005 through 2008 for selected streamgage 

stations in the Upper Yampa River watershed, Colorado ......................................................9

5. Geology of the Upper Yampa River watershed, Colorado....................................................11

6. Distribution of specific conductance, pH, acid neutralizing capacity, and 

concentrations of dissolved sulfate and dissolved manganese in stream water, 

by subwatershed, Upper Yampa River watershed, Colorado, 1975 through 2009 ...........26

7. Distribution of specific conductance, and concentrations of unfiltered sulfate, 

unfiltered total phosphorus, and total recoverable iron at Yampa River at Milner 

(site 151), by month, Upper Yampa River watershed, Colorado, 1975 through 2007 ........27

8. Location of water-quality sampling sites with exceedances of Colorado 

Department of Public Health and Environment in-stream water-quality standards 

for physical properties (pH, water temperature, dissolved oxygen), dissolved 

solids, and unfiltered sulfate and U.S. Environmental Protection Agency 

recommended concentrations for total phosphorus, Upper Yampa River watershed, 

Colorado, 1975 through 2009 ......................................................................................................29

9. Daily Maximum Temperature (DM), Maximum Weekly Average Temperature 

(MWAT), and daily average streamflow with exceedances of Colorado 

Department of Public Health and Environment (CDPHE) in-stream water-quality 

standards for water temperature for June–September DM, June–September 

MWAT, October–May DM, and October–May MWAT for Yampa River at Steamboat 

Springs (site 153), Upper Yampa River watershed, Colorado, 2002 though 2005..................35

10. Major cation and anion percentages and water type for water-quality samples 

collected from selected stream sites, by subwatershed, Upper Yampa River 

watershed, Colorado, 1975 through 2009................................................................................41

11. Concentrations of flow-adjusted unfiltered total phosphorus in Yampa River at 

Steamboat Springs (site 153), Upper Yampa River watershed, Colorado, 1997 

through 2008 ................................................................................................................................45

12. Location of water-quality sampling sites with exceedances of Colorado 

Department of Public Health and Environment in-stream water-quality standards 

for trace elements, Upper Yampa River watershed, Colorado, 1975 through 2009 ................. 54

13. Streamflow and concentrations of suspended sediment and unfiltered total 

phosphorus in Elkhead Creek above Long Gulch (site 40), Upper Yampa River 

watershed, Colorado, July 1995 through September 2003...................................................57
v

14. Depth profiles of specific conductance, pH, water temperature, and dissolved 

oxygen concentrations for Stagecoach Reservoir and Steamboat Lake, Upper 

Yampa River watershed, Colorado, July 25, 2006 ..................................................................59

15. Location of groundwater wells completed in selected geologic units, Upper 

Yampa River watershed, Colorado, 1975 through 1989 and 1998........................................62

16. Specific conductance in groundwater samples from selected geologic units 

in the Upper Yampa River watershed, Colorado, 1975 through 1986..................................67

17. Major cation and anion percentages and water type for groundwater samples 

from selected geologic units in the Upper Yampa River watershed, Colorado, 

1975 through 1984 .......................................................................................................................73

18. Location of stream sites with macroinvertebrate data, Upper Yampa River 

watershed, Colorado, 1975 through 2008................................................................................84

Tables

1. Summary of active, water year 2010, streamgage stations in the Upper Yampa 

River watershed, Colorado..........................................................................................................8

2. Reservoirs in the Upper Yampa River watershed, Colorado, with active storage 

capacity of 4,000 acre-feet or more...........................................................................................9

3. Number of sample sites, period of water-quality record, and number of waterquality and biological samples collected by various organizations at selected 

site types in the Upper Yampa River watershed, Colorado, 1975 through 2009 ...............12

4. Summary of procedures used to aggregate data for selected physical 

properties, streamflow, or water-quality constituents for streams, Upper 

Yampa River watershed, Colorado...........................................................................................14

5. Colorado Department of Public Health and Environment Section 303(d) list of 

impaired waters and monitoring and evaluation list for the Upper Yampa River 

watershed, Colorado, 2012........................................................................................................17

6. Number of stream sites and samples with water-quality data for the Upper 

Yampa River watershed and subwatersheds, Colorado, by physical properties 

or constituent group,1975 through 2009..................................................................................19

7. Period of water-quality record and number of water-quality samples collected 

per year from streams, by physical properties or constituent group, Upper Yampa 

River watershed and subwatersheds, Colorado, 1975 through 2009 .................................20

8. Summary statistics for selected physical property water-quality data and 

Colorado Department of Public Health and Environment in-stream water-quality 

standards for stream sampling sites in the Upper Yampa River watershed and 

subwatersheds, Colorado, 1975 through 2009 .......................................................................24

9. Results of Seasonal Kendall trend analysis for selected physical properties 

or water-quality constituents at three stream sites in the Upper Yampa River 

watershed, Colorado, 1997 through 2008................................................................................28

10. Stream water-quality sites with data in exceedance of Colorado Department 

of Public Health and Environment in-stream water-quality standards for selected 

physical properties and water-quality constituents and U.S. Environmental 

Protection Agency recommended concentrations for total phosphorus, Upper 

Yampa River watershed, Colorado, 1975 through 2009.........................................................30

11. Number of sample days with water temperature at Yampa River at Steamboat 

Springs (site 153) not meeting Colorado Department of Public Health and 

Environment in-stream water-quality standards, July 26, 2002, through 

April 13, 2005................................................................................................................................37
vi

12. Summary statistics for dissolved solids and selected major ion water-quality 

data and Colorado Department of Public Health and Environment in-stream 

water-quality standards for stream sampling sites in the Upper Yampa River 

watershed and subwatersheds, Colorado, 1975 through 2009 ...........................................39

13. Summary statistics for selected nutrient water-quality data and Colorado 

Department of Public Health and Environment in-stream water-quality standards 

for stream sampling sites in the Upper Yampa River watershed and subwatersheds, 

Colorado, 1975 through 2009 .....................................................................................................43

14. Summary statistics for selected trace element and uranium water-quality data 

and Colorado Department of Public Health and Environment in-stream waterquality standards for stream sampling sites in the Upper Yampa River watershed 

and subwatersheds, Colorado, 1975 through 2009................................................................46

15. Summary statistics for selected coliform bacteria water-quality data and 

Colorado Department of Public Health and Environment in-stream water-quality 

standards for stream sampling sites in the Upper Yampa River watershed and 

subwatersheds, Colorado, 1975, 1976, and 1989 through 2009............................................56

16. Summary statistics for suspended-sediment water-quality data for stream 

sampling sites in the Upper Yampa River watershed and subwatersheds, 

Colorado, 1975 through 2003 .....................................................................................................58

17. Summary statistics for selected water-quality data and Colorado Department 

of Public Health and Environment in-stream water-quality standards for sampling 

sites in Lake Elbert and Long Lake Reservoir, Upper Yampa River watershed, 

Colorado .......................................................................................................................................58

18. Concentrations of selected physical properties and constituents in nearsurface and near-bottom water-quality samples, Stagecoach Reservoir 

and Steamboat Lake, Upper Yampa River watershed, Colorado, July 25, 2006 ...............60

19. Period of water-quality record and number of water-quality samples collected 

per year from groundwater wells, by physical properties or constituent group, 

Upper Yampa River watershed Colorado, 1975 through 1989 and 1998.............................63

20. Number of wells sampled and groundwater-quality samples collected from 

selected geologic units in the Upper Yampa River watershed, Colorado, 

1975 through 1989 and 1998.......................................................................................................63

21. Summary statistics for selected physical property water-quality data and 

exceedances of Colorado Department of Public Health and Environment 

water-quality standards for groundwater in the Upper Yampa River watershed, 

Colorado, 1975 through 1989 and 1998 ....................................................................................64

22. Summary statistics for dissolved solids and selected major ion water-quality 

data and exceedances of Colorado Department of Public Health and Environment 

water-quality standards for groundwater in the Upper Yampa River watershed, 

Colorado, 1975 through 1989 and 1998 ....................................................................................68

23. Summary statistics for selected nutrient water-quality data and exceedances of 

Colorado Department of Public Health and Environment water-quality standards 

for groundwater in the Upper Yampa River watershed, Colorado, 1975 through 

1989 and 1998 .....................................................................................................................................74

24. Summary statistics for selected trace element water-quality data and exceedances 

of Colorado Department of Public Health and Environment water-quality standards 

for groundwater in the Upper Yampa River watershed, Colorado, 1975 through 1989 

and 1998 ..............................................................................................................................................77

25. Trace elements with Colorado Department of Public Health and Environment 

water-quality standards for groundwater and presence or absence of exceedances

for samples collected in the Upper Yampa River watershed, Colorado, 1975 through

1989 and 1998 .....................................................................................................................................83
vii

Conversion Factors, Abbreviations, and Datum

Multiply By To obtain

acre-foot (acre-ft) 1,233 cubic meter (m3)

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)

foot (ft) 0.3048 meter (m)

inch per year (in/yr) 25.4 millimeter per year (mm/yr)

square meter (m2) 10.76 square foot (ft2)

square mile (mi2) 2.590 square kilometer (km2)

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:

°F=(1.8×°C)+32

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 

(NAVD 88).

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83) 

or the North American Datum of 1927 (NAD 27).

Altitude, as used in this report, refers to distance above the vertical datum.

Water year, as used in this report, refers to the period October 1–September 30 and is 

designated by the year in which it ends.

Specific conductance is given in microsiemens per centimeter at 25 degrees Celsius (μS/cm).

Concentrations of chemical constituents in water are given in either milligrams per liter (mg/L) 

or micrograms per liter (μg/L). A value of 1 mg/L equals 1 part per million; a value of 1 μg/L 

equals 1 part per billion.

Additional Abbreviations, Acronyms, and Symbols

AMLE adjusted maximum likelihood estimation

ANC acid neutralizing capacity

CaCO3 calcium carbonate

CDOA Colorado Department of Agriculture

CDPHE Colorado Department of Public Health and Environment

col/100 mL colonies per 100 milliliters

DM daily maximum temperature

E. coli Escherichia coli

HCO3

– bicarbonate

HH human health

MCL maximum contaminant level

MWAT maximum weekly average temperature

N nitrogen

NH3 un-ionized ammonia

NH4

+ ammonium

P phosphorus

ROS regression of ordered statistics

SMCL secondary maximum contaminant level

STORET STOrage and RETrieval 

TVS table value standard

USEPA U.S. Environmental Protection Agency

USGS U.S. Geological Survey

UYRW Upper Yampa River watershed

WS water supply

< less than
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Water-Quality Assessment and Macroinvertebrate 

Data for the Upper Yampa River Watershed, Colorado, 

1975 through 2009

By Nancy J., Bauch, Jennifer L. Moore, Keelin R. Schaffrath, and Jean A. Dupree

capacity to neutralize inputs of acidic water than streams with 

drainage basins underlain by sedimentary rocks. The spatial distribution of dissolved solids and major ions was similar to that 

for specific conductance. Values and concentrations also tended 

to be lower during snowmelt runoff than other times of the year.

Many concentrations of dissolved nitrite and nitrate and 

unfiltered total ammonia in stream-water samples were less than 

laboratory detection levels; however, about 14 percent of the 

samples with unfiltered total phosphorus data had concentrations that exceeded federal recommendations. A statistically 

significant upward trend in unfiltered total phosphorus concentrations at a Yampa River site in Steamboat Springs may reflect 

population growth and land-use changes that have occurred 

upstream from the site.

About two-thirds of the concentration data for many trace 

elements in stream-water samples also were less than laboratory 

detection levels. Maximum concentrations of the various trace 

elements occurred in main-stem Yampa River subwatersheds 

and seemed to depend on the lithology of the rocks underlying 

a subwatershed. Some sites were not in attainment of state 

aquatic-life standards for dissolved copper, dissolved selenium, 

and total recoverable iron and water-supply standards for dissolved iron and manganese.

Concentrations of the bacterium Escherichia coli in five 

stream samples collected from 1994 through 2003 were greater 

than the state recreation standard. High values could be due to 

recreational users of a stream, wildlife, and (or) livestock.

Water-quality data for Lake Elbert, Long Lake Reservoir, 

Stagecoach Reservoir, Steamboat Lake, and Elkhead Reservoir 

for various periods of time since 1985 were summarized or 

analyzed. Lake Elbert and Long Lake Reservoir were very 

dilute and have little capacity to neutralize inputs of acid. 

Anoxic conditions (dissolved oxygen concentrations less than 

0.5 milligrams per liter) at depth were indicated for Stagecoach 

Reservoir and Steamboat Lake during July 2006 and for 

Elkhead Reservoir on some days from July 1995 through 

August 2001. The trophic status of Elkhead Reservoir ranged 

from oligotrophic to eutrophic.

A total of 816 groundwater-quality samples collected from 

328 wells during 1975 through 1989 and 1998 were analyzed 

for this study. The sampled wells are concentrated in the middle 

latitudes of the UYRW. About 66 percent of the wells with 

Abstract

A study was initiated in 2009 by the U.S. Geological 

Survey (USGS), in cooperation with Routt County, the 

Colorado Water Conservation Board, and the City of Steamboat 

Springs, to compile and analyze historic water-quality data 

and assess water-quality conditions in the Upper Yampa River 

watershed (UYRW) in northwestern Colorado. Water-quality 

data for samples collected by federal, state, and local agencies 

for various periods from 1975 through 2009 were compiled 

and assessed for streams, lakes, reservoirs, and groundwater in 

the UYRW, including the Elkhead Creek subwatershed and the 

Yampa River watershed that is upstream from Elkhead Creek. 

For selected physical-property and chemical-constituent data 

for samples collected from surface-water sites and groundwater wells in the UYRW, this report: (1) characterizes available 

data through statistical summaries, (2) analyzes the spatial and 

temporal distribution of water-quality conditions, (3) identifies 

temporal trends in water quality, where possible, (4) provides 

comparisons to federal and state water-quality standards and 

recommendations, and (5) identifies factors affecting the quality of water. In addition, the availability and characteristics of 

macroinvertebrate data collected in the UYRW are described.

Water-quality data were compiled for 211 stream sites 

located throughout much of the watershed. A total of 5,861 

stream-water samples with data for physical properties, dissolved solids, major ions, nutrients, trace elements, uranium, 

coliform bacteria, and suspended-sediment concentrations collected from 1975 through 2009 were analyzed. The amount of 

data collected varied by year and site.

Values of specific conductance and values and concentrations for other water-quality constituents depended, in part, 

on the geology underlying a stream’s drainage basin. Specific 

conductance values were lower in areas with igneous and 

metamorphic rocks than in areas with sedimentary rocks. 

Water temperature for main-stem Yampa River sites increased 

in a downstream direction; water temperatures in one Yampa 

River site exceeded Colorado Department of Public Health and 

Environment (CDPHE) water-quality standards for protection of 

aquatic life. Streams with drainage basins underlain by igneous 

and metamorphic rocks tended to have softer water and a lower 
2 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

water-quality data were sampled only once. Samples were 

collected from wells that tap aquifers in 12 named geologic 

units and geologic units that have not been identified. More 

groundwater samples were collected from wells completed in 

the unknown geologic units, Mesaverde Group, and terrace 

alluvium than from wells completed in other geologic units.

Analysis of groundwater data for physical properties 

indicates that specific conductance was lower in samples collected from igneous and metamorphic rocks and sedimentary 

rocks of nonmarine origin than sedimentary rocks of marine or 

marine-nonmarine origin. Values of pH not meeting CDPHE 

groundwater standards were most commonly collected from the 

flood-plain alluvium and unknown geologic units. The CDPHE 

water-supply standard for dissolved sulfate in groundwater was 

exceeded in concentrations from about one-half of the samples 

collected, most commonly for samples collected from the terrace alluvium, Mesaverde Group, and unknown geologic units.

All dissolved nitrite concentrations were well below 

CDPHE maximum contaminant level (MCL) for nitrite in 

groundwater, and fewer than 5 percent of dissolved nitrate 

plus nitrite concentrations were greater than the CDPHE MCL 

for nitrate. Almost all dissolved and unfiltered total phosphorus concentrations in groundwater samples were less than 

0.1 milligram per liter.

More than 80 percent of samples collected for some trace 

elements had concentrations that were less than or equal to 

laboratory detections levels. Exceedances of CDPHE waterquality standards were rare for most trace elements. Only 

one or two samples each had concentrations of dissolved 

arsenic, beryllium, copper, lead, molybdenum, and selenium that exceeded human-health standards, MCLs, and (or) 

agricultural-use standards. Less than 4 percent of the samples 

had dissolved cadmium concentrations that exceeded the 

CDPHE MCL for cadmium in groundwater. Agricultural-use 

standards were exceeded for about 13 percent of dissolved 

boron samples and less than 1 percent of dissolved zinc samples. Exceedances of CDPHE secondary maximum contaminant levels were detected for about 10 percent of dissolved 

iron samples and more than one-half of dissolved manganese 

samples. These samples with exceedances were collected from 

the Mancos Shale, valley-fill deposits, and unknown geologic 

units (dissolved iron) and terrace alluvium, Mesaverde Group, 

and unknown geologic units (dissolved manganese).

Macroinvertebrate community and population data were 

available for 66 stream sites in the UYRW for various periods from 1975 through 2008. A summary of results from one 

study of Yampa River sites in Steamboat Springs indicates 

that changes observed in community characteristics between 

2005 and 2008 may be due to upstream effects or large-scale 

environmental factors rather changes in water quality within 

the stream reach.

Synthesis of water-quality data indicates that the values 

and concentrations of many physical properties and constituents 

in surface-water samples for the UYRW are likely controlled 

primarily by geology, streamflow, and land use. The quality of 

groundwater in the UYRW is a function of various physical and 

geochemical processes, including precipitation, the depositional 

environment of the aquifer sediments, type of sediments that 

groundwater moves through, dissolution of soluble minerals in rocks and soils, and ion exchange reactions. Constituents that are issues of concern for aquatic life, human health, 

or suitability of water for various uses include those on the 

CDPHE 2012 303(d) (federal Clean Water Act Section 303d) 

list of impaired waters or monitoring or evaluation list for surface water. Other constituents in stream water or groundwater 

that are or could be issues of concern include those that commonly have concentrations that exceed standards or that could 

affect technical qualities of water. This could include unfiltered 

sulfate, unfiltered total phosphorus, and dissolved copper in 

stream water; pH, unfiltered nitrate plus nitrite, and dissolved 

copper in groundwater; and hardness, dissolved solids, iron, 

and manganese in stream water and groundwater. Analysis of 

stream-water and groundwater data for changes in water quality 

over time was limited because of the absence of long-term data 

collection in the Upper Yampa River Watershed.

Introduction

The Yampa River, the largest primarily free-flowing tributary to the Colorado River in the Upper Colorado River basin 

(Blinn and Poff, 2005), is a highly valued resource known for 

its biological diversity, largely unaltered natural condition, and 

generally high water quality. The Upper Yampa River watershed (UYRW) (fig. 1), defined for this study as the Elkhead 

Creek subwatershed and the Yampa River watershed upstream 

from Elkhead Creek in northwestern Colorado, is undergoing increased land and water development to support growing 

municipal demands, recreational tourism, and second-home 

development that present water-quality challenges. A plan 

for the Yampa River watershed was developed in 2002 for 

the Colorado Department of Public Health and Environment 

(CDPHE) and the Yampa River Basin Partnership 

(Montgomery Watson Harza, 2002). The main goals of the 

plan were to address water-quality concerns and provide for 

the maintenance of high quality water in the Yampa watershed. 

State and local stakeholders that rely on and manage the water 

resources of the watershed are interested in an assessment of 

water quality to aid in the preservation and management of 

the UYRW. Stakeholders have specifically expressed a need 

for a compilation and evaluation of the available historic 

UYRW water-quality data to assess the effects of growth and 

associated land-use changes on water quality, identify spatial 

and temporal gaps within available water-quality data, and 

evaluate spatial and temporal trends in water quality. In 2009, 

the U.S. Geological Survey (USGS), in cooperation with 

Routt County, the Colorado Water Conservation Board, and 

the City of Steamboat Springs, initiated a study to compile 
Introduction 3

Figure 1. Location of the Upper Yampa River watershed, Colorado.

"

"

"

"

"

"

Yampa

Oak

Creek

Steamboat

Springs

Hayden

Phippsburg

Milner

MOFFAT

ROUTT

JACKSON

GRAND

RIO

BLANCO

GARFIELD ARFIELD Bear River

Grassy Creek

DryCreek

YampaRiver

First Creek

WolfCr

Mad Cr

OakCr

Trout Creek

Ch mi ney

Creek

Walton Creek

Foidel Creek

Elk River

Yampa River

Yampa River

LostDogCr

Fish Creek

Service Creek

MorrisonCreek

BushyCr

Sage Creek

Fish Cr

Elkhead Cr

Little

Morrison

Creek

Elkhead CreekElkhead Creek

Elkhead

Reservoir

Pearl

Lake

Fish Creek

Reservoir

Steamboat

Lake

Stillwater

Reservoir

Yamcolo

Reservoir

Lake

Catamount

Stagecoach

Reservoir

Yamcolo

Reservoir

Long Lake

Reservoir

Lake

Elbert

Sarvis

Creek

Wilderness

Flat Tops

Wilderness

Mount

Zirkel

Wilderness

Flat Top 

Mountains

Williams Fork

Mountains

Elkhead Mountains

Park Range Park Range

Gore Range

Continental

Divide

Continental

Divide

Chuck Lewis

State Wildlife

Area (SWA)

0 5 10 MILES

0 5 10 KILOMETERS

Yampa River

subwatershed 1

Yampa River

subwatershed 2

Elk River

subwatershed

Yampa River

subwatershed 3

Yampa River

subwatershed 4

Elkhead Creek

subwwatershed

Active coal

mining area

Yampa

coal field

Yampa

coal field

Yampa

coal field

Yampa

coal field

Base from U.S. Geological Survey digital data,

1:100,000, Universal Transverse Mercator, 

Zone 13 North, North American Datum of 1983

Yampa coal field boundary and location of 

active mine from U.S. Geological Survey Energy Data

http://certmapper.cr.usgs.gov/geoportal/catalog/main/home.page

40°30'

40°45'

107°15'

107°00'

106°45'

40°15'

40°00'

" DENVER

Upper Yampa River 

watershed

COLORADO
4 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

water-quality and macroinvertebrate data and assess waterquality conditions in the UYRW. Specific objectives of the 

study were to:

• Develop and maintain a web-accessible water-quality 

database that provides agencies, researchers, consultants, and interested stakeholders with equal access to 

historic and current water-resources information;

• Evaluate available water-resources data for uniformity 

and suitability to meet the needs of water- and landresource managers and decision makers as well as the 

public and other stakeholders, and perform and publish 

an assessment of water-resource conditions;

• Design and implement regional water-quality monitoring strategies to effectively fill identified data gaps 

by reducing duplication of effort while still meeting a 

broad base of data-collection objectives; and 

• Upon implementation of the monitoring program, periodically assess the new data to update factors affecting 

water-resource conditions.

Purpose and Scope

The purpose of this report is to describe and provide an 

analysis of water-quality data collected in the UYRW by federal, state and local agencies from 1975 through 2009. Waterquality data include physical properties (specific conductance, 

pH, water temperature, dissolved oxygen, hardness, and acid 

neutralizing capacity), streamflow, dissolved solids, major 

ions, nutrients, trace elements, uranium, coliform bacteria, and 

(or) suspended sediment for streams, lakes, reservoirs, and 

(or) groundwater wells. Methods used to analyze these data 

are described. For selected physical properties and waterquality constituents in the UYRW, this report: (1) characterizes 

available data through statistical summaries, (2) evaluates the 

spatial and temporal distribution of water quality, (3) identifies 

temporal trends in water quality, where possible, (4) provides 

comparisons to federal and state water-quality standards and 

recommendations, and (5) identifies factors affecting the quality of water. In addition, the availability and characteristics of 

macroinvertebrate data collected in the UYRW are described.

Study Area

The UYRW drains approximately 1,800 square miles of 

the Yampa River watershed west of the Continental Divide 

in northwestern Colorado (fig. 1) (U.S. Geological Survey, 

2010). The boundaries of the watershed extend from the 

Williams Fork and Flat Top Mountains in the southwestern 

and southern portions of the watershed, respectively, to the 

Gore and Park Ranges and the Continental Divide to the east 

and to the Elk River and Elkhead Creek drainages to the north 

and west, respectively. Altitudes in the watershed range from 

more than 12,000 feet (ft) (above North American Vertical 

Datum of 1988) in the Flat Top Mountains and Park Range to 

6,400 ft near the confluence of the Yampa River with Elkhead 

Creek west of the town of Hayden. The UYRW is almost 

entirely contained within Routt County, with small portions in 

Grand, Garfield, Jackson, Moffat, and Rio Blanco Counties.

Human activity in the UYRW began at least 1,000 

years ago when the Native Americans used the Yampa River 

valley for summer hunting (http://yampavalley.info/centers/

history_%2526_genealogy, accessed June 2012). Trappers of 

European origin came to the valley around 1820. Development of the valley was sparked with the 1861 discovery of 

gold at Hahns Peak (not shown on fig. 1) in the northern Elk 

River subwatershed. The vast coal resources in the region 

and the potential for grazing lands were noted by Ferdinand 

Hayden during a 1874 survey across northwestern Colorado 

(Mehls and Mehls, 1991). Initially, coal was mined for local 

use; larger-scale production began in 1909 with improved 

transportation to and from Steamboat Springs. For the greater 

part of the past century, ranching, including hay and wheat 

production, and mining were the economic bases of the valley. 

More recently, recreational-based tourism (skiing, fishing, 

hunting, rafting, camping, among others) and second-home 

development became important economic drivers. These 

accounted for approximately 45 percent of the total jobs in 

Routt County during 2008 (State Demography Office, 2010a). 

The Steamboat Springs Ski Resort attracts skiers from around 

the world. During the 2008–2009 ski season, the number of 

skier days (skier day is one individual visiting a ski area for 

skiing or snowboarding for any part of one day) at Steamboat 

Ski Resort was 959,603 (C. Bannister, Colorado Ski Country 

USA, oral commun., 2010). Agriculture and coal mining 

each accounted for only about 2.5 percent of the total jobs 

during 2008.

The population of Routt County during 2008 was 

estimated to be 22,931 (State Demography Office, 2010b). 

The largest township is Steamboat Springs (12,280); and 

the next largest is Hayden (1,672). About 34 percent of the 

population in the county lived in unincorporated areas. From 

2000 through 2008, the population of Routt County grew by 

more than 16 percent and was largely driven by recreationrelated tourism.

The dominant land cover in the UYRW is forest, which 

accounts for about 57 percent of the total land area (fig. 2) 

(LaMotte, 2008). Other prominent land covers are shrub/scrub 

(about 26 percent) and grassland/pasture (about 13 percent). 

Barren; developed; developed, open space; cultivated crops; 

water; and wetlands account for about 4 percent of the land 

cover. Approximately 49 percent of the land in Routt County 

is publicly owned (Montgomery Watson Harza, 2002). This 

includes three national forests (Arapaho, Routt, and White 

River), Bureau of Land Management lands, and lands held by 

agencies of the state of Colorado (State Land Board, Division 

of Wildlife, and State Parks). Vegetation is diverse throughout the watershed. Alpine areas are predominantly evergreen 

and aspen forest, whereas areas around Steamboat Springs 
Introduction 5

Figure 2. Land cover in the Upper Yampa River watershed, Colorado, 2001.

"

"

"

Elk River

subwatershed

Yampa River

subwatershed 1

Yampa River

subwatershed 3

Elkhead Creek

subwatershed

Yampa River

subwatershed 4 Yampa River

subwatershed 2

Steamboat

Springs

Yampa

Hayden

Oak Creek

107°15'

107°00'

106°45'

40°45'

40°30'

40°00'

40°15'

EXPLANATION

Water

Developed, open space

Developed

Barren (rock/sand/clay)

Forest

Shrub/scrub

Grassland/pasture

Cultivated crops

Wetlands

Base from U.S. Geological Survey, (LaMotte, 2008),

National Land Cover Database 2001,

Albers Conical Equal Area, 1983

0 5 10 MILES

0 5 10 KILOMETERS

Elkhead Creek

Elk River

Yampa River

Trout Creek

Yamp

River
6 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

are subalpine and generally have Douglas fir, ponderosa pine, 

and aspen. Areas south from Steamboat Springs, around the 

town of Yampa, in the lower Elk River valley, and in the lower 

Yampa River valley are semiarid with shrubs, grassland, and 

rangeland (fig. 2), which are grazed.

Variation of temperature and precipitation in the 

UYRW is typical of that found in mountainous and semiarid regions of Colorado. Annual temperatures in the towns 

of Steamboat Springs and Hayden range from an average 

minimum temperature of 0.9 and 4.7° Fahrenheit (F), respectively, during January to an average maximum temperature 

of 82.6 and 85.6 °F, respectively, during July (High Plains 

Regional Climate Center, 2010). Frost-free days typically 

occur during late June through early September in Steamboat 

Springs and early June through mid-September in Hayden 

(http://www.cmg.colostate.edu/gardennotes/749.pdf, accessed 

June 2012). Almost 24 inches per year (in/yr) of precipitation 

falls on average in Steamboat Springs and 17 in/yr falls in 

Hayden. Much of the precipitation falls as snow throughout 

the winter months, which melts during spring. Snowfall averages 166 in/yr in Steamboat Springs and 107 in/yr in Hayden. 

Hydrology and Water Resources

The Yampa River originates in the Flat Top Mountains 

as the Bear River, flows northward to the town of Yampa, 

and becomes the Yampa River in town where Chimney Creek 

converges with the Bear River (fig. 1). Major tributaries to the 

Yampa River include Oak Creek, upstream from Steamboat 

Springs; the Elk River, downstream from Steamboat Springs; 

and Elkhead Creek, downstream from Hayden. Minor tributaries include Fish Creek east of Steamboat Springs, Fish Creek 

southwest of Steamboat Springs, Trout Creek, Foidel Creek, 

and Sage Creek. Streams in the Mount Zirkel, Flat Tops, 

and Sarvis Creek Wilderness Areas have been classified as 

outstanding waters by the CDPHE (Colorado Department of 

Public Health and Environment, 2009a, 2010).

The USGS and the Colorado Division of Water 

Resources currently (1

water year 2010) operate 13 streamgage 

stations in the UYRW (fig. 3, table 1). Streamflow data have 

been collected during different periods of record at the 13 

sites, beginning as early as 1904. Real-time streamflow data 

for the USGS stations are available at http://co.water.usgs.gov/

infodata/surfacewater.html (accessed June 2012). Real-time 

data for the Colorado Division of Water Resources stations 

are available at http://www.dwr.state.co.us/SurfaceWater/data/

division.aspx?div=6 (accessed June 2012). The USGS also 

collected streamflow data at 36 additional stations for various 

periods of record between 1913 and 2008.

Streamflow in the UYRW is dominated by snowmelt, 

with increasing flows in April, maximum flows in May 

and June, and decreasing flows in July. Streamflow from 

August through March is often dominated by base flow from 

1

A water year is the 12-month period from October 1 to September 30. It is 

designated by the year in which it ends.

groundwater discharge. Mean monthly streamflow for 2005 

through 2008 for two sites on the Yampa River and one site 

on Elk River show the seasonal pattern of streamflow in the 

watershed (fig. 4). Mean monthly streamflow was lowest at 

Yampa River at Steamboat Springs (site 153) and highest at 

Yampa River above Elkhead Creek (site 146). Low streamflow 

during August at Yampa River at Steamboat Springs (site 153) 

could be of concern because of the possible effects of low 

streamflow on fish (higher water temperature and lower dissolved oxygen) and on river rafting.

Development of water resources in the UYRW has 

focused on irrigation, municipal and industrial diversions, 

and state-sponsored reservoir development (Colorado Water 

Conservation Board, 2009). Irrigation has changed little since 

the late 1800s. There have been only small increases in the 

amount of acreage irrigated since the construction of new 

ditches and storage systems. The first substantial municipal 

water system in the UYRW was developed during the 1950s 

at Steamboat Springs. The City of Steamboat Springs and 

the Mt. Werner Water and Sanitation District divert most of 

their municipal water supplies directly from Fish Creek east 

of Steamboat Springs. When flow in the creek is insufficient 

for supply, water can be released from Fish Creek Reservoir 

for augmentation (Colorado Water Conservation Board, 

2009). The two public suppliers also can withdraw water from 

alluvial wells adjacent to the Yampa River. The wells, however, are not a preferred source of municipal water because 

the quality of the water is not as good as that of the surfacewater supplies. Surface water is the primary water source for 

the Towns of Hayden and Oak Creek. Groundwater is the 

primary water source for the Towns of Phippsburg and Yampa 

and part of the source for Hayden (Topper and others, 2003; 

U.S. Environmental Protection Agency, 2010b). 

Two small ditches (maximum water right of 43 cubic 

feet per second, ft3

/s) divert water from the UYRW into the 

Colorado River basin (Colorado Water Conservation Board, 

2009). One ditch diverts water from the outlet works of 

Yamcolo Reservoir (fig. 1), and the other diverts water from 

the headwaters of Service Creek. The Steamboat Springs Ski 

Resort diverts water from an alluvial well near the Yampa 

River just upstream from Steamboat Springs for making artificial snow, typically from October through January (Colorado 

Water Conservation Board, 2009). A portion of the artificial 

snowpack is consumptively used during winter and spring; the 

remaining portion returns to the stream during spring snowmelt. Concerns about the water supply in the watershed are 

growing with the possibility of future large-scale diversions 

and increased water demands.

Eight reservoirs in the UYRW can each store 

4,000 acre-feet of water or more (table 2). In addition to storage, the water is used for irrigation, recreation, and municipal 

and industrial purposes. The largest reservoirs are Stagecoach 

Reservoir, Steamboat Lake, and Elkhead Reservoir (table 2). 

Because reservoirs in the watershed are small compared to other 

reservoirs in the Upper Colorado River basin and are located 

primarily in the headwaters of the Yampa River, streamflow in 

the Yampa River is largely free-flowing.
Introduction 7

Figure 3. Location of selected stream-water sampling sites and active, water year 2010, streamgage stations, Upper Yampa 

River watershed, Colorado.

Elkhead

Reservoir

Pearl

Lake

Fish Creek

Reservoir

Steamboat

Lake

Stillwater

Reservoir

Lake

Catamount

Stagecoach

Reservoir

Yamcolo

Reservoir

Long Lake

Reservoir

Lake

Elbert

Elkhead

Reservoir

Pearl

Lake

Fish Creek

Reservoir

Steamboat

Lake

Stillwater

Reservoir

Lake

Catamount

Stagecoach

Reservoir

Yamcolo

Reservoir

Long Lake

Reservoir

Lake

Elbert

Yampa River 

subwatershed 1

Yampa River 

subwatershed 3

Yampa River 

subwatershed 2

Elk River

subwatershed

Yampa River 

subwatershed 4

Yampa River 

subwatershed 1

Yampa River 

subwatershed 3

Yampa River 

subwatershed 2

Elk River

subwatershed

Elkhead Creek

subwatershed

Yampa River 

subwatershed 4

Lost DogCr

Fish Creek

Service Creek

MorrisonCreek

BushyCr

Sage Creek

FishCr

Bea r River Bea r River

Trout Creek

Oak Cree kOak Cree k

Foidel Creek

Grassy Cr

Dry Cre ek

Elkh e a d Cr Elkh e a d Cr

Yampa River

Yampa River

Yamp a Ri ver Yamp a Ri ver

First CreekFirst Creek

Elk River Elk River

Little

Morrison

Creek

Wolf Cr

#

#

#

#

#

#

#

#

#

#

#

#

# #

#

#

#

#

#

##

#

#

##

#

#

#

# #

##

#

#

#

#

#

#

#

#

#

# #

#

#

#

#

##

#

#

#

#

#

#

#

#

###

#

#

#

#

#

##

#

#

#

#

#

#

#

#

#

#

#

#

##

#

#

##

#

#

#

#

#

#

#

##

#

#

#

#

##

## #

#

#

# #

#

#

#

#

#

#

#

#

#

#

#

#

#

# #

#

#

#

#

# # #

#

#

##

#

#

#

# # # #

#

#

#

# #

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

#

1

2

3

4

5

6

7

14

15

16

18

19

20

21

23

25

26

27

28

29

30

31

32, 127 32, 127

33

34, 149 34, 149

35

36

37

38

39

40

41

42

43

44

45

47

48

50, 67

51

52

55 74

75

55

56

57

58

59

60

61

62 63, 64

65

66

68

69

70

71

72

73

74

75

76

77

78

79

80, 110

81

82

83

84

123

129

169

171

84

85

86

87

88

89

90

91

92

93

94

95

97

98, 99

100

102

103

104

106

107

109

112

114

115

116

117

118

119

120

121

122

138, 139, 158

122

123

125

126

128

129

131

137

138, 139, 158

140, 150

142

143

145

146

147

148 151

152

155

156

160

162

165

177

162

164

165

167

169

170

171

173 22, 24

101, 141, 154, 168

105 113

134

177

179

Base from U.S. Geological Survey digital data, 

1:100,000, Universal Transverse Mercator, 

Zone 13 North, North American Datum of 1983

Enlargement of 

Steamboat Springs area

40o00'

0 5 10 MILES

0 5 10 KILOMETERS

Yampa coal field boundary and location of 

active mine from U.S. Geological Survey Energy Data

http://certmapper.cr.usgs.gov/geoportal/catalog/main/home.page

40°15'

40°30'

40°45'

107°15'

107°00'

106°45'

#

#

#

#

#

#

#

###

#

#

#

#

#

#

#

#

#

#

#

#

#

# #

#

#

#

#

#

#

#

Spring Creek

Fish Creek

Butcher knife Cr

Soda Creek

Yampa R

Prie st Creek

Burgess Creek

9

10 12

46

49

53

54

108 111

124

130

132

133

136

144

153

172

174

176

178 8

9

10

11

12

13

46

49

53

54

96

108 111

124

130

132

135 133

136

144

153

159

17

161

163

166 172

174

175

176

178 8

157

EXPLANATION

# Streamwater sampling site and site 

 number (appendix 3)

# Streamwater sampling site, streamgage 

 station, and site number (table 1, 

 appendix 3)

# Streamgage station and site number

 (table 1, appendix 3)

4

147

177

Yampa

coal field

Yampa

coal field

Yampa

coal field

Active coal

mine area

Steamboat

Springs
8 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009 Table 1. Summary of active, water year 2010, streamgage stations in the Upper Yampa River watershed, Colorado. [USGS, U.S. Geological Survey; CODWR, Colorado Division of Water Resources; WY, water year. USGS information from the USGS National Water Information System (NWIS), http://waterdata.usgs.gov/nwis. CODWR information from http://www.dwr.state.co.us/SurfaceWater/data/division.aspx?div=6. A water year is defined as a 12-month period beginning October 1 and ending September 30 of the following year. A water year is designated as the year in which it ends.] Site number (See figure 3) USGS or CODWR streamgage station identifier USGS or CODWR streamgage station name Agency collecting data Period of streamflow record 177 MORBSCCO Morrison Creek below Silver Creek CODWR 4/22/2009–WY 2010, seasonal1 147 09237450 Yampa River above Stagecoach Reservoir, CO USGS 10/1/1988–WY 2010 158 09237500 Yampa River below Stagecoach Reservoir, CO USGS 10/1/1939–9/30/1944, 10/1/1956–9/30/1972, 10/1/1984–WY 2010 142 YAMABVCO2 Yampa R above Lake Catamount nr Steamboat Springs CODWR 10/1/2003–WY 2010 49 09238900 Fish Cr at Upper Sta nr Steamboat Springs, CO USGS 10/1/1966–9/30/1972, 5/1/1982–WY 2010 123 WLTNCKCO3 Walton Creek near Steamboat Springs, CO. CODWR 10/1/1965–WY 2010 153 09239500 Yampa River at Steamboat Springs, CO USGS 10/1/1904–9/30/1906, 3/1/1910–WY 2010 178 09240020 Yampa River below Soda Creek at Steamboat Spgs, CO USGS 6/25/2008–WY 2010, seasonal4 179 WILBSLCO Willow Creek below Steamboat Lake CODWR 10/1/1978–WY 2010 33 09242500 Elk River near Milner, CO USGS 10/1/1904–9/30/1906, 10/1/1909–9/30/1927, 4/1/1990–WY 2010 146 09244490 Yampa River above Elkhead Creek near Hayden, CO USGS 3/16/2004–WY 2010 40 09246200 Elkhead Creek above Long Gulch, near Hayden, CO USGS 8/10/1995–WY 2010 43 09246500 Elkhead Creek near Craig, CO USGS 1/1/1910–12/31/1918, 7/11/2008–WY 2010 1Site is operated seasonally from late April through October.

2Site is located at or near Colorado Department of Public Health and Environment site 12807.3Site also is USGS site 09238500.4Site is operated seasonally from May through August.
Methods of Data Compilation, Review, and Analysis 9

Geology

The UYRW is underlain by rocks of Precambrian age to 

unconsolidated Quaternary alluvium (fig. 5) (Tweto, 1979). 

The oldest rocks are in the eastern one-third (western side of 

Gore and Parks Ranges) of the watershed. These mountainous 

areas are underlain by igneous (granitic and mafic) rocks and 

metamorphic (gneiss, schist, and migmatite) rocks. Permian and 

Triassic sedimentary rock (sandstone, shale, siltstone) occupy a 

small portion of the area north from Steamboat Springs (fig. 5). 

The western two-thirds of the watershed is underlain by sedimentary rocks of Cretaceous age and sedimentary and igneous 

rocks of Tertiary age. Dominant Cretaceous rock types include 

sandstones and shale, and major coals beds composing the 

UYRW portion of the Yampa coal field (fig. 1). Tertiary rocks 

include sandstones and shales. Broad valleys and small rounded 

hills are present in areas with less resistant shales, and ridges 

and mesas are present in areas with more resistant sandstones. 

The Tertiary basalts and intrusive and volcanic rocks form the 

Flat Top Mountains in the southern portion of the watershed 

and the area north from Steamboat Lake. The youngest formations include the unconsolidated surficial deposits and rocks 

of Quaternary age, including landslide and valley-fill deposits, 

glacial drift, gravels, and alluvium. Landslide deposits are most 

common in the Flat Tops Mountains. Glacial drift, primarily 

from Pinedale and Bull Lake glaciations, occurs on the western 

side of the Gore and Park Ranges. The youngest gravels and 

alluvium are located primarily along the Yampa and Elk Rivers.

Cretaceous and Tertiary sedimentary rocks contain soluble 

materials and trace elements, including arsenic, barium, boron, 

iron, manganese, nickel, selenium, and strontium. Formations 

that are seleniferous include the Lewis Shale, Williams Fork 

Formation and Iles Formation of the Mesaverde Group, and 

Mancos Shale (Butler and others, 1996; Stephens and Waddell, 

1998). Major coal deposits in the Yampa coal field occur in the 

Upper Cretaceous Williams Fork and Iles Formations in northwestern Colorado (Johnson and others, 2000). In the eastern 

part of the coal field that is in the UYRW, the principal coal 

beds in the middle coal group of the Williams Fork Formation 

are, in ascending order, Wolf Creek, Wadge, and Lennox (Bass 

and others, 1955). The coal deposits were formed in alternating mixed marine and nonmarine environments at the western 

edge of the Late Cretaceous Western Interior Seaway. Most 

sulfur in the deposits is in the form of organic sulfur rather than 

pyritic sulfur and sulfate sulfur (Affolter, 2000). High contents 

of strontium, barium, and phosphorus are found in the Iles 

Formation compared to other Cretaceous coals in the Colorado 

Plateau (Arizona, Colorado, New Mexico, and Utah) (Affolter, 

2000). Similarly, high contents of arsenic and manganese are 

found in the Lennox and Wolf Creek coal beds of the Williams 

Fork Formation. Currently (2012), one underground coal mining operation, at the Twentymile Mine, is active in the UYRW 

portion of the Yampa coal field (fig. 1).

More than 150 hot springs are located in the Steamboat 

Springs area (Frazier, 2000). Thermal waters for the springs 

probably are meteoric waters that have been heated at depths of 

12,000 to 15,000 ft (Lund, 2006). Heated water most likely rises 

to the surface from a network of faults and fractures that cross 

the region. Chemical constituents in the springs include sodium, 

chloride, sulfate, bicarbonate, and lithium.

Methods of Data Compilation, 

Review, and Analysis

Various methods of data compilation, review, and analysis of water-quality data were used to assess water-quality conditions in the UYRW. Data from several sources were compiled into a web-accessible UYRW water-quality database. 

Figure 4. Mean monthly streamflow for 2005 through 2008 

for selected streamgage stations in the Upper Yampa River 

watershed, Colorado.

Table 2. Reservoirs in the Upper Yampa River watershed, 

Colorado, with active storage capacity of 4,000 acre-feet or more.

[ac-ft, acre feet. Multiple purpose means irrigation, recreation, municipal, and 

industrial uses. Data from Colorado Water Conservation Board (2009)]

Reservoir

(see figure 1)

Active storage

capacity

(ac-ft)

Purpose1

Stillwater Reservoir 5,175 Irrigation

Fish Creek Reservoir 4,042 Municipal

Pearl Lake 5,657 Fishery and recreation

Steamboat Lake 23,064 Fishery and recreation

Elkhead Reservoir 10,422 Multiple

Lake Catamount 7,422 Fishery and recreation

Yamcolo Reservoir 8,028 Irrigation

Stagecoach Reservoir 30,000 Multiple 1

In addition to storage.

5,000

4,000

3,000

2,000

1,000

0

January

February

March

April

May

June

July

August

September

October

November

December

Month

Mean monthly streamflow,

in cubic feet per second

2005 through 2008

Site name and number

Yampa River at Steamboat Springs, 

 CO (153)

Elk River near Milner, CO (33)

Yampa River above Elkhead Creek 

 near Hayden, CO (146)

EXPLANATION
10 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

"

"

"

Elk River

subwatershed

Yampa River

subwatershed 1

Yampa River

subwatershed 3

Elkhead Creek

subwatershed

Yampa River

subwatershed 2

Yampa River

subwatershed 4

Steamboat

Springs

Yampa

Hayden

Oak Creek

Kl

Xg

Km

Kw

Tbp

Kls

Kls

Ki

Km

Tbp

Ki

Tbp

Xfh

Tf Xfh

Kw

Qd

Ki

Tw

Ki

Xfh

Xg

Km

Ql

Ql

Qd

Tbb

Km

Ql

Xb

Xfh

Km

Kl

Xb

Qd

Km

Tv

Qd

Ql

Kl

Tbb

Xfh

Xfh

Qg

Xfh

Qdo

Qd

Tbp

Xb

Xb

Xg

Qg

Ql

Tv

Qd

Km

Kl

Tui

Qa

Qa

Qa

Tbp

Qa

Qd

Tbp

TRcc

Qgo

Qd

Tbp

Tui

Qd

Tbp

Qdo

Km

Tbp

Tbp

Mz

Xg

Qd

Ki

Qg

Qd

Ql

Xb

Xfh

Kw

Qdo

Ql

Xm

Qg

Qd

Km

Tbp

Qg

Xfh

Km

Km

Xb

Tui

KJds

Qg

Xfh

Tbb

Qg

Xg

Tui

Xg

Qa

Ql

Qdo

Xg

Qd

Ki

Qg

Xg

Kw

Km

Tbp

Tbp

TRPr

Qg

Yg

Yg

Ql

Ql

KJds

Xfh

Tui

Tui

Xg

Tv

Qd

Tbb

Tbb

KJds

KJds

KJds

Qa Mz

Xfh

Xg

Tbp

Km

KJds

Kls

Tui

Tbb

Xfh

TRcc

Mz

Tui

Tv

KJds

Tbb

Tbb

Qgo

Km

Tc

KJde

KJds

Xg

Tbp

Tbp

Tbp

Tui

Tui

Tui

Qd

Km

TRcc Xg

Qdo

Qdo

Tbp

Tui

Tui TRPr

Xfh

TRPr

Tbb

Xfh

Kl

KJds

Xfh

Tc

Tv

TRPr

TRPr

TRcc

TRcc

TRcc

Xb

Xg

Tui

Xg

Tbb

Tbp

KJds

KJds

KJds

Tbb

KJds

Tui

TRcc

Qdo

Xg

Xg

TRcc

TRch

Xb

Kw

Yampa River

Base from U.S. Geological Survey, 

Stoeser and others, 2005,

1:100,000 to 1:1,000,000, 

North American Datum of 1983

Yampa

coal field

0 5 10 MILES

0 5 10 KILOMETERS

Trout Creek

Elkhead Creek

Elk River

Yampa River

107°15'

107°00'

106°45'

40°45'

40°30'

40°00'

40°15'
Methods of Data Compilation, Review, and Analysis 11

Data Sources and Water-Quality Database

Data summarized and analyzed in this study were collected and reported by the U.S. Environmental Protection 

Agency (USEPA), U.S. Department of Agriculture Forest 

Service, USGS, Colorado Department of Agriculture (CDOA), 

Colorado Department of Public Health and Environment 

(CDPHE), Colorado Division of Wildlife Riverwatch 

Program, and the City of Steamboat Springs (data collected 

by GEI Consultants, Inc.) (table 3). Data originally were 

obtained in an electronic format from the USGS National 

Water Information System, USEPA STOrage and RETrieval 

(STORET) Data Warehouse, and GEI Consultants, Inc., and 

were merged to form the UYRW water-quality database 

(http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml). The 

database primarily contains data for physical properties and 

chemical constituents in samples collected from surface water 

(streams, canals, diversions, lakes, and reservoirs), groundwater (wells, springs, and seeps), mining discharges (tunnel, 

shaft, or mine), and wastewater-treatment-plant discharges, 

including effluent, during most years from 1944 through 2009. 

However, the year 1975 was chosen as the starting year for 

data analysis because major development of coal resources in 

the watershed began that year (Colorado Geological Survey, 

2005). Data for water-quality constituents are reported as 

filtered (through a 0.45 micron filter, described as “dissolved”) 

or unfiltered. Data can also be reported as total (for example, 

total nitrogen, which includes all forms of nitrogen) or total 

recoverable (which involves incomplete digestion of particulate matter in the laboratory).

Data Quality Assurance

After data for selected physical properties and chemical 

constituents were retrieved from the UYRW water-quality 

database, a number of quality-assurance procedures were 

applied to the data. The USEPA has established low and high 

values for 190 water-quality properties and constituents as an 

edit-checking procedure for data entered into STORET since 

November 1993 (National Park Service, 2001). Low and high 

values for 63 physical properties and chemical constituents 

were used for edit-checking of water-quality data retrieved 

from the UYRW database (appendix 1). Using the edit-checking procedures, temperature values of –17.8 and 90 degrees 

Celsius (°C) and a dissolved oxygen concentration of 779 milligrams per liter (mg/L) were deleted. Trace-element data 

greater than the high values were not deleted. Trace elements 

can occur in very high concentrations in areas with historical 

mining activities or in areas with naturally high mineralization 

because of geology. For a given individual sample with dissolved- and unfiltered-concentration data, the dissolved concentration was checked against the unfiltered concentration. 

Both data values would be marked for deletion if the dissolved 

Figure 5 (above and facing). Geology of the Upper Yampa River 

watershed, Colorado.

Quality-assurance checks and data aggregation steps were 

applied to pertinent data retrieved from the online database. 

The resulting physical-property and chemical constituent data 

were summarized statistically, displayed spatially in figures, 

analyzed, and interpreted. Data were analyzed for temporal 

trends and compared to state of Colorado and federal waterquality standards and recommendations. The following discussion describes methods used to process, evaluate, and interpret 

water-quality data for the UYRW.

EXPLANATION

Quaternary modern alluvium

Quaternary gravels and alluvium

Quaternary older gravels and alluviums

Quaternary glacial drift of Pinedale and Bull Lake Glaciations

Quaternary older glacial drifts

Quaternary landslide deposits

Tertiary Browns Park Formation

Tertiary Wasatch Formation

Tertiary Coalmont Formation

Tertiary Fort Union Formation

Tertiary basalt flows and tuff, breccia, and conglomerate of 

 late-volcanic bimodal suite

Tertiary volcanic rocks

Upper Tertiary intrusive rocks of 20 million years before present (Ma)

Cretaceous Laramie Formation-shales, claystone, sandstone, and 

 major coal beds

Cretaceous Lewis Shale

Cretaceous Williams Fork Formation-sandstone, shale, and major coal beds

Cretaceous Dakota Sandstone

Cretaceous Iles Formation-sandstone and shale. 

Cretaceous Mancos Shale

Cretaceous and Jurassic Dakota, Burro Canyon, Morrison, Wanakah, 

 and Entrada formations

Cretaceous and Jurassic Dakota, Morrison, and Sundance formations

Jurassic Morrison Formation and Sundance Formation (shale and siltstone), 

 and Entrada Sandstone

Triassic Chugwater Formation

Triassic Chinle and Chugwaters Formations

Triassic and Permian rocks

Mesozoic rocks

Precambrian bioitite gneiss, schist, and migmatite

Precambrian felsic and hornblende gneisses

Precambrian granitic rocks of 1,400 Ma

Precambrian granitic rocks of 1,700 Ma

Precambrian mafic rocks of 1,700 Ma

Water

Yampa coal field

Mega Annum (millions of years before present)

Qg

Qgo

Qd

Qdo

Ql

Tbp

Tw

Tc

Tf

Tbb

Tv

Tui

Kl

Kls

Kw

Kd

Ki

Km

KJde

KJds

Jms

TRch

TRcc

TRPr

Mz

Xb

Xfh

Yg

Xg

Xm

Ma

Qa
12 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009 Table 3. Number of sample sites, period of water-quality record, and number of water-quality and biological samples collected by various organizations at selected site types in the Upper Yampa River watershed, Colorado, 1975 through 2009. [No., number; --, no data] Organization collecting samples Site type Streams Lakes and reservoirs Groundwater wells Macroinvertebrates No. of sites Period of water-quality record No. of samples No. of sites Period of water-quality record No. of sample days1 No. of sites Period of water-quality record No. of samples No. of sites Period of water-quality record No. of sample days City of Steamboat Springs (GEI Consultants, Inc.)

8 2007–2008 32 -- -- -- -- -- -- 4 2005, 

2007–2008

212

Colorado Department of Agriculture3 -- -- -- -- -- -- 6 1998 6 -- -- --Colorado Department of Public 

Health and Environment3

56 1975–2007 866 4

4 1990, 2006 4 -- -- -- 37 51997–2008 61

Colorado Division of Wildlife 

Riverwatch Program3

14 1990–2004 1,046 -- -- -- -- -- -- -- -- --

U.S. Environmental 

Protection Agency3

2 2000–2001 4 1 1985 1 -- -- -- -- -- --

U.S. Forest Service3 3 1975, 

1978–79

35 -- -- -- -- -- -- -- -- --

U.S. Geological Survey6 128 1975–2009 3,878 37 1975–76, 

1978–79, 

1983, 

1985–2009

364 322 71975–1989 81,574 25 1975 25

Total 211 5,861 42 369 328 1,580 66 98

1Samples collected at multiple depths on the same day are counted as one sample day.2Four samples were collected on each sample day at a site.3Data retrieved from U.S. Environmental Protection Agency’s STOrage and RETrieval (STORET) Data Warehouse.4Two sites in Stagecoach Reservoir are at the same location and are counted as one site, as are two sites in Steamboat Lake. For each body of water, samples collected near the top and bottom of the water 

column at the same location have different site identification numbers in the Upper Yampa River watershed database but are counted as one site in this table.

5No data for 1999, 2002, 2004, and 2007.6Data retrieved from the National Water Information System (NWIS).7No data for 1985.8Count consists of 810 samples with water-quality data and 764 samples with water-level data only. Count of water-quality samples does not include multiple (14) water-quality samples collected on one day 

from selected wells.
Methods of Data Compilation, Review, and Analysis 13

concentration was greater than the unfiltered concentration 

by more than 10 percent. All dissolved and unfiltered data 

retrieved from the UYRW database met this edit-check procedure. An ion charge balance was calculated for individual 

samples with sufficient data (calcium, magnesium, sodium, 

potassium, alkalinity, chloride, and sulfate concentrations) to 

calculate the balance. All charge balances were within 10 percent, and no data were deleted. One dissolved iron concentration for a particular site was 100-times greater than the next 

highest concentration at the site and was excluded from this 

study. Twelve measurements of instantaneous discharge with a 

value of 0 were deleted.

Many of the reported concentrations for water-quality 

constituents showed concentrations of 0. According to Hem 

(1992), concentrations of 0 can imply that the amount of a 

constituent present in a sample was less than a detection level 

and that the analytical procedure could not detect a concentration less than the detection level. For 427 individual analyses 

of stream-water samples, constituent concentrations with a 

value of 0 were converted to the minimum detection level for 

the constituent of interest. Most (311 of 427) reported concentrations of 0 in stream-water samples were for trace elements, 

but 0 was also reported for nutrients (108), major ions (5), 

and dissolved uranium (3). Constituent concentrations for 438 

individual analyses of groundwater samples were converted 

from a 0 value to the lowest detection level; values of 0 were 

reported for trace elements (353) or nutrients (85). A total 

of 801 individual analyses of stream-water samples and 620 

individual analyses of groundwater samples resulted in a data 

remark code of M (presence of constituent verified but not 

quantified); these data were excluded from the analysis for 

this study.

For a large portion of the water-quality data, limited 

metadata and (or) quality-assurance data were available. 

Therefore, it is possible that some data may contain errors 

that were not detected during the quality-assurance review. 

Assumptions regarding water-quality collection methods and 

laboratory analytical techniques used by different data sources 

were made based on available information. No distinctions 

between water-quality data collection methods and laboratory analytical techniques were made when metadata were 

unavailable to support these distinctions. Disparities between 

data from different sources that resulted from differences 

in water-quality collection methods and laboratory analytical techniques could affect the precision and accuracy of 

the statistical results. Although the effect of methodological 

differences could not be quantified in this analysis, robust 

statistical methods were used to limit the influence of outliers 

on statistical results of the analysis. It has been documented 

for USGS trace-element data that dissolved concentrations 

of arsenic, boron, beryllium, cadmium, chromium, copper, 

lead, mercury, and zinc collected before 1992 may have been 

contaminated during sample collection and field processing (USGS, 1991). An in-depth review of these data for this 

study could not be conducted because field quality-assurance 

data were not available for analysis. For all data that could 

not be quality assured, it is assumed that measurements made 

at the time of sampling and results from laboratory analyses 

are of good quality. These data are used as reported in the 

UYRW database.

Data Aggregation

Data on physical properties and chemical constituents 

were compiled from the various sources, each with differing 

laboratory methods and sampling and reporting conventions. 

For many physical properties and chemical constituents, data 

were available under one or more parameter codes for the 

same property or constituent. Equivalent parameter codes for 

different physical properties and chemical constituent groups 

were combined for data-analysis purposes by using the data 

aggregation groups summarized in table 4. Measurement 

or concentration data for the first parameter code listed in 

the table for each constituent were preferred for analysis. If 

these data were not available, data for the second parameter 

code listed were used. This aggregation continued for each 

parameter code in a constituent group, resulting in a single 

constituent name with one reporting convention. All of the 

aggregated nitrate data, for example, are in the form of nitrate 

as nitrogen instead of nitrate as nitrate. Procedures used to 

aggregate nutrient data follow those used by Mueller and 

others (1995).

In natural waters, ammonia nitrogen can be in the 

form of aqueous ammonia (un-ionized ammonia, NH3) or 

ammonium (NH4

+

). In most natural waters (pH less than 

9.24), ammonia nitrogen occurs as ammonium rather than 

un-ionized ammonia (Hem, 1992). For the USGS and other 

federal and state agencies, the sum of un-ionized ammonia 

concentrations and ammonium ions is reported as “ammonia” 

or “total ammonia.” In this report, the sum is reported as 

“total ammonia.”

Censored Values

Computing summary statistics for the water-quality data 

presented in this report were complicated by the presence of 

multiple detection or reporting levels for censored data for many 

chemical constituents. Censored data for this study are data 

reported as “less than” a particular laboratory detection level or 

reporting level. When water-quality results were reported with 

censored (below laboratory detection or reporting level) values, 

estimates of percentile values, including the 50th percentile or 

median, were calculated using the Kaplan-Meier, adjusted maximum likelihood estimation (AMLE), or regression of ordered 

statistics (ROS) methods following the recommendations of 

Helsel (2005). The Kaplan-Meier method was used when less 

than 50 percent of the data were censored values. When censored values were 50 to 80 percent, the ROS method was used 

when there were fewer than 50 samples or when there were 50 

or more samples and the distribution of data was not normal. 
14 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009 Table 4. Summary of procedures used to aggregate data for selected physical properties, streamflow, or water-quality constituents for streams, Upper Yampa River watershed, Colorado.—Continued [No., number; μS/cm, microsiemens per centimeter at 25 degrees Celsius; °C, degrees Celsius; mg/L, milligrams per liter; CaCO3, calcium carbonate; Ca, calcium; Mg, magnesium; ft3/s, cubic feet per second; S, sulfur; N, nitrogen; NO2, nitrite; *, constituent computed from procedure listed for nitrite, as N; NO3, nitrate; NH3, un-ionized ammonia; NH4

+, ammonium; P, phosphorus; PO4, phosphate; μg/L; micrograms 

per liter; Fe, iron; col/100 mL; colonies per 100 milliliters; m-TEC MF, membrane-Thermotolerant Escherichia coli Membrane Filtration; M-FC MF, Membrane-Fecal Coliform Membrane Filtration. Procedures used to aggregate nutrient data follow those used by Mueller and others (1995)]

Physical property or 

constituent (reporting units) Physical property or constituent name Parameter code1 No. of samples

Physical properties and streamflow

Specific conductance (μS/cm) Specific conductance, water, unfiltered, μS/cm at 25 °C 00095 3,890

Specific conductance, water, unfiltered, field, μS/cm at 25 °C 00094 415

pH (standard units) pH, water, unfiltered, field, standard units 00400 3,104

pH, water, unfiltered, laboratory, standard units 00403 36

Hardness (mg/L as CaCO3

) Hardness, water, mg/L as CaCO3 00900 1,615

Hardness,water, total, Ca Mg calculated, mg/L as CaCO3 46570 787Hardness, water, filtered, calculated, mg/L as CaCO3 00906 32

Acid neutralizing capacity (mg/L as CaCO3

) Acid neutralizing capacity, water, unfiltered, fixed endpoint (pH 4.5) titration, field, mg/L as CaCO3 00410 476

Acid neutralizing capacity, water, unfiltered, fixed endpoint (pH 4.5) titration, laboratory, mg/L as CaCO3 90410 716Acid neutralizing capacity, water, unfiltered, mg/L as CaCO3 00431 1,052

Streamflow (ft3/s) Discharge, instantaneous, ft3/s 00061 3,665

Discharge, ft3/s 00060 18Flow, estimated, stream, ft3/s 74069 1

Dissolved solids

Dissolved solids, (mg/L) Residue, water, filtered, sum of constituents, mg/L 70301 989

Residue on evaporation, dried at 180 °C, water, filtered, mg/L 70300 754

Major ions

Bicarbonate, dissolved (mg/L) Bicarbonate, water, unfiltered, fixed endpoint (pH 4.5) titration, field, mg/L P00440 160

Bicarbonate, water, filtered, inflection-point titration method (incremental titration method), field, mg/L P00453 24

Sulfate, dissolved (mg/L) Sulfate, water, filtered, mg/L 00945 1,018

Sulfate, water, dissolved, as S, mg/L 78462

(multiplied by 3.0)

2

Chloride, dissolved (mg/L) Chloride, water, filtered, mg/L 00940 1,014

Chloride, dissolved in water, mg/L 00941 2

Nutrients

Nitrite, unfiltered (mg/L as N) Nitrite, water, unfiltered, mg/L as N 00615 34

Nitrite, water, unfiltered, mg/L as NO2 71855

(multiplied by 0.30446)

61

Nitrate, dissolved (mg/L as N) Nitrate plus nitrite, water, filtered, mg/L as N, minus 2nitrite, filtered, mg/L as N 00631 1,092

00613 628

Nitrate, water, filtered, mg/L as N 00618 4

Nitrate, unfiltered (mg/L as N) Nitrate plus nitrite, water, unfiltered, mg/L as N, minus 2nitrite, unfiltered, mg/L as N 00630 1,155

* 95

Nitrate, water, unfiltered, mg/L as NO3 71850

(multiplied by 0.2259)

62
Methods of Data Compilation, Review, and Analysis 15

Table 4. Summary of procedures used to aggregate data for selected physical properties, streamflow, or water-quality constituents for streams, Upper Yampa River watershed, Colorado.—Continued[No., number; μS/cm, microsiemens per centimeter at 25 degrees Celsius; °C, degrees Celsius; mg/L, milligrams per liter; CaCO3, calcium carbonate; Ca, calcium; Mg, magnesium; ft3/s, cubic feet per second; S, sulfur; N, nitrogen; NO2, nitrite; *, constituent computed from procedure listed for nitrite, as N; NO3, nitrate; NH3, un-ionized ammonia; NH4

+, ammonium; P, phosphorus; PO4, phosphate; μg/L; micrograms 

per liter; Fe, iron; col/100 mL; colonies per 100 milliliters; m-TEC MF, membrane-Thermotolerant Escherichia coli Membrane Filtration; M-FC MF, Membrane-Fecal Coliform Membrane Filtration. Procedures used to aggregate nutrient data follow those used by Mueller and others (1995)]

Physical property or 

constituent (reporting units) Physical property or constituent name Parameter code1 No. of samples

Nutrients—Continued

Total ammonia, unfiltered (mg/L as N) Ammonia, water, unfiltered, mg/L as N 00610 184

Ammonia + ammonium as N, total NH3 + NH4

+ in water, mg/L 82230 843

Orthophosphate (mg/L as P) Orthophosphate, water, filtered, mg/L as P 00671 836

Orthophosphate, water, unfiltered, mg/L as P 70507 16Phosphate, water, unfiltered, mg/L as PO4 00650

(multiplied by 0.3261)

2

Trace elements

Aluminum, total recoverable (μg/L) Aluminum, water, unfiltered, recoverable, μg/L 01104 51

Aluminum, water, unfiltered, recoverable, μg/L 01105 304

Chromium, dissolved (μg/L) Chromium (VI), water, filtered, μg/L 01032 21

Chromium, water, filtered, μg/L 01030 133

Chromium, total recoverable (μg/L) Chromium, water, unfiltered, recoverable, μg/L 01034 172

Chromium, water, unfiltered, recoverable, μg/L 01118 59

Copper, total recoverable (μg/L) Copper, water, unfiltered, recoverable, μg/L 01042 724

Copper, water, unfiltered, recoverable, μg/L 01119 253

Iron, total recoverable (μg/L) Iron, total recoverable in water as Fe μg/L 00980 690

Iron, water, unfiltered, recoverable, μg/L 01045 1,339

Lead, total recoverable (μg/L) Lead, water, unfiltered, recoverable, μg/L 01051 281

Lead, water, unfiltered, recoverable, μg/L 01114 264

Manganese, total recoverable (μg/L) Manganese, water, unfiltered, recoverable, μg/L 01055 1,228

Manganese, water, unfiltered, recoverable, μg/L 01123 268

Nickel, total recoverable (μg/L) Nickel, water, unfiltered, recoverable, μg/L 01067 186

Nickel, water, unfiltered, recoverable, μg/L 01074 26

Silver, total recoverable (μg/L) Silver, water, unfiltered, recoverable, μg/L 01077 88

Silver, water, unfiltered, recoverable, μg/L 01079 84

Zinc, total recoverable (μg/L) Zinc, water, unfiltered, recoverable, μg/L 01092 650

Zinc, water, unfiltered, recoverable, μg/L 01094 32

Coliform bacteria

Escherichia coli (col/100 mL) Escherichia coli, modified m-TEC MF method, water, col/100 mL 90902 21

Escherichia coli, m-TEC MF method, water, col/100 mL 31633 101

Fecal coliform (col/100 mL) Fecal coliform, M-FC MF (0.7 micron) method, water, col/100 mL 31613 127

Fecal coliform, M-FC MF (0.7 micron) method, water, col/100 mL 31625 153Fecal coliform, M-FC MF (0.45 micron) method, water, col/100 mL 31616 119 1Parameter codes are from the U.S. Geological Survey National Water Information System (NWIS) and the U.S. Environmental Protection Agency Data STOrage and RETrieval (STORET) Data Warehouse.

2Values less than the detection level and missing values were not included in the calculation.
16 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

For 50 or more samples and a normal distribution, the AMLE 

method was used. When 80 percent or more of the data were 

censored values, the median value was not computed; only the 

minimum and maximum values are reported in summary tables. 

Data from 11 analyses with a concentration reported as “greaterthan” a particular concentration were excluded from this study. 

Some water-quality results that are less than laboratory detection levels were reported as “estimated” (E) values rather 

than censored values. Because of improvements in laboratory 

analytical techniques, a chemist is able to report an estimated 

concentration when a compound meets all criteria for identification, but the concentration value is less than the laboratory 

reporting level (Childress and others, 1999).

Water-Quality Standards

In-stream water-quality standards for surface water in 

the state of Colorado have been established by the CDPHE to 

protect the beneficial uses of surface water, including protection of cold- and warm-water aquatic life, recreation, water 

supply, and agriculture (Colorado Department of Public Health 

and Environment, 2009a, 2010). The standards are applied to 

stream segments and water bodies on the basis of water-use 

classification (appendix 2) (Colorado Department of Public 

Health and Environment, 2009a, 2010). Water-quality standards can vary between segments of different streams and 

between different segments on the same stream. For this study, 

the authors assigned a stream segment to each stream site 

on the basis of the segment descriptions in the water-quality 

standards table for the Upper Colorado River basin (Colorado 

Department of Public Health and Environment, 2010). Instream water-quality standards have not been established for 

all physical properties and chemical constituents.

Two types of numeric water-quality standards, fixed values 

and table values standards (TVSs), have been established by 

the CDPHE. Fixed values are maximum contaminant levels 

(MCLs), secondary maximum contaminant levels (SMCLs), 

and a recreation-based standard (appendix 2). The MCLs and 

SMCLs apply to drinking water from public water systems. 

An MCL is a legally enforceable standard for drinking water; 

an SMCL is a nonenforceable guideline for contaminants that 

may have cosmetic (skin or tooth discoloration), aesthetic 

(taste, odor, and color), or technical (corrosion and staining) 

effects. For streams, lakes, or reservoirs in the UYRW that are 

not drinking-water supplies, the MCLs are used in this study as 

guidelines for interpreting water quality. Table value standards, 

established for aquatic-life protection, are calculated values 

based on published formulas and include acute and chronic 

classifications. Except for temperature, an acute standard is a 

value that is not to be exceeded by a constituent concentration in 

a single sample or by an average concentration for all samples 

collected during a one-day period. A chronic standard is a value 

not to be exceeded by a concentration in a single representative sample or by an average concentration for all samples 

collected during a 30-day period. Two types of TVSs have 

been established by CDPHE for water temperature. The Daily 

Maximum Temperature (DM) is the highest 2-hour average 

water temperature recorded for a given 24-hour period, and the 

Maximum Weekly Average Temperature (MWAT) is the maximum average of multiple, equally spaced daily water temperature measurements collected over 7 consecutive days (Colorado 

Department of Public Health and Environment, 2009a). The 

TVS for total ammonia varies depending on fish species, pH, 

and water temperature. Table value standards for trace elements 

vary depending on stream hardness. Hardness-dependent TVSs 

were calculated using the mean of available hardness data that 

corresponds to the trace-element data. If these hardness data 

were not available, the median hardness value for the site, other 

sites on the same stream, or sites on nearby streams was used.

The CDPHE has not established an in-stream waterquality standard for total phosphorous. The USEPA, however, 

has recommended that total phosphorous concentrations be 

less than 0.1 mg/L for streams that do not flow directly into 

lakes and reservoirs and less than 0.05 mg/L for streams that 

do flow directly into lakes and reservoirs to control eutrophication of the water bodies (U.S. Environmental Protection 

Agency, 2000). Unfiltered total phosphorus data for the 

UYRW are compared to the USEPA recommended concentrations to provide an environmentally relevant context to 

concentrations of total phosphorus in steams. Streams used in 

the comparison are those with standards for other nutrients.

For this study, determination of attainment or 

nonattainment of a standard for a stream site is based on the 

15th and 85th percentiles of the data for pH, the 15th percentile 

of the data for dissolved oxygen, the 85th percentile of data for 

dissolved and unfiltered constituents, and the 50th percentile 

of the data for total recoverable constituents (Water Quality 

Control Division, 2002) in samples with more than two data 

points. As required under Section 303(d) of the federal Clean 

Water Act, the CDPHE established the 303(d) list of impaired 

waters and monitoring and evaluation list (table 5) (Colorado 

Department of Public Health and Environment, 2012).

Water-quality standards for groundwater in the state of 

Colorado have been established by the CDPHE to protect 

the beneficial uses of groundwater (Colorado Department of 

Public Health and Environment, 2009b). Water-quality data 

for groundwater in the UYRW are compared to standards for 

agricultural use in livestock watering and “domestic uses,” 

which are existing or potential future uses of groundwater 

for household or family uses, including drinking, gardening, 

municipal, and (or) farm uses (Colorado Department of Public 

Health and Environment, 2009b). Standards for domestic 

uses include human-health (HH) standards and SMCLs. HH 

standards have been established to protect the public from 

acute and chronic effects from exposure to contaminated water 

(Colorado Department of Public Health and Environment, 

2009b). Many HH standards are MCLs. Comparison of waterquality data to groundwater standards is used as a guideline for 

interpreting water quality but is not used for legally enforceable purposes.
Methods of Data Compilation, Review, and Analysis 17

Table 5. Colorado Department of Public Health and Environment Section 303(d) list of impaired waters and monitoring and evaluation 

list for the Upper Yampa River watershed, Colorado, 2012.

[--, no listing; Mn, manganese; Se, selenium; Hg, mercury; FCA, fish consumption advisory; USFS, U.S. Department of Agriculture Forest Service; Fe, iron; 

dis, dissolved; Zn, zinc; DO, dissolved oxygen; E. coli, Escherichia coli; trec, total recoverable; Pb, lead. Data from Colorado Department of Public Health and 

Environment (2012). Description of stream segments are in Colorado Department of Public Health and Environment (2010)]

Stream

segment Segment description Segment portion

Clean Water Act 

Section 303(d)

impairment

Monitoring and 

evaluation list 

parameter

2a Mainstem of the Yampa River from Wheeler Creek 

to Oak Creek

Yampa River below 

Stagecoach Reservoir

-- Mn, Se

2b All lakes and reservoirs tributary to the Yampa River, 

Elkhead Creek, and the Little Snake River

Elkhead Reservoir, 

Lake Catamount

Aquatic life use

(Hg FCA)

--

2c Yampa River, from Oak Creek to Elkhead Creek All -- Water temperature

3 All tributaries to Yampa River, except for specific 

listings on USFS land

Bushy Creek Sediment --

3 All tributaries to Yampa River, except for specific 

listings on USFS land

Walton Creek -- Mn

3 All tributaries to Yampa River, except for specific 

listings on USFS land

Little Morrison Creek -- Fe (dis), Zn

4 Little White Snake Creek, source to Yampa River All -- DO

8 Elk River source to Yampa River Elk River below 

Morin Ditch

E. coli --

8 Elk River including tributaries and wetlands from 

the source to Yampa River

Lost Dog Creek -- Hg

13b Foidel Creek and tributaries, Fish Creek, Middle 

Creek and tributaries

Fish Creek -- E. coli

13d Dry Creek including all tributaries and wetlands 

from the source to the Yampa River

Below Seneca 

sample location 8

(WSD5)

Se --

13d Dry Creek including all tributaries and wetlands 

from the source to the Yampa River

All Fe (trec)

(snowmelt season)

--

13d Dry Creek including all tributaries and wetlands 

from the source to the Yampa River

Dry Creek below 

Routt County Road 53

-- E. coli, Pb

13e Sage Creek, Grassy Creek and tributaries Sage Creek below 

Routt County Road 51D

Se --

15 Mainstem of Elkhead Creek and tributaries Calf 

Creek and 80A Road on the Dry Fork of Elkhead 

Creek, to confluence with the Yampa River

Elkhead Creek Aquatic life

(provisional)1

--

1

Listing is based on macroinvertebrate data rather than water-quality data.

Temporal Trend Analysis

Trend analyses were performed with the TIBCO 

Spotfire® S+program using the USGS library package 

ESTREND (Schertz and others, 1991). Analyses were conducted on selected physical properties and chemical constituents for stream sites with at least 10 years of quarterly data 

for a period of record ending after 2000 and with less than 

10-percent censored data. Selected physical properties and 

chemical constituents were analyzed by using the seasonal 

Kendall test (Hirsch and others, 1982; Helsel and Hirsch, 

2002). The seasonal Kendall test, a nonparametric rank-based 

procedure, was used to analyze water-quality data for monotonic changes in concentrations with time. Seasonality in 

water-quality data are accounted for by comparing data for different seasons; for example, data for January through March 

are compared only with data for January through March, April 

through June with April through June, and so forth. Because of 

the strong correlation that exists between many water-quality 

constituents and streamflow, most water-quality data were 

flow-adjusted prior to testing for trends, using the streamflow 

measured at the time of sample collection. Flow adjustment 

removes that variability in concentration that is related to 

natural changes in streamflow, allowing for trends caused 

by other means, such as human activities, to be more readily 

identified. When flow-adjustment was applied to the data, the 

data were regressed against streamflow, and the residuals of 

the resulting equation were used in the seasonal Kendall test. 

Most often, the best flow-adjustment procedure is to regress 

the log-transformed constituent data against log-transformed 

streamflow (D.K. Mueller, U.S. Geological Survey, oral 

commun., 2010).

A trend was determined to be present when the p-value of 

the statistical test was less than 0.05. The smaller the p-value, 

the stronger the evidence is to reject the null hypothesis that 

there is no relation between concentration and time: that no 

trend exists (Helsel and Hirsch, 2002). A trend in an upward 

direction was identified when a constituent concentration 
18 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

increased more often over time than it decreased. The estimated trend, in percent per year, is reported from the model 

calculations. The trend slope is an estimate of the yearly 

change in a value or concentration for the tested time period 

and is presented as a percentage of the median value per year 

or concentration per year. Trend results differ depending on 

the time period used in the trend analysis. Trends that are identified for a particular constituent at a site for one time period 

may not be identified when another time period is used. A 

trend also may be statistically significant but not environmentally significant. For example, a statistically significant upward 

trend with a rate of change of 0.5 mg/L per year for a constituent may have little environmental relevance if the average 

concentration is 100 mg/L.

Water-Quality Assessment

This section summarizes water-quality data for streams, 

lakes, reservoirs, and groundwater in the UYRW. General 

information on physical properties and chemical constituents 

are presented first, followed by detailed analyses of waterquality data for physical properties, major ions, nutrients, trace 

elements, uranium, coliform bacteria, and (or) suspended sediment for selected streams, lakes, reservoirs, and groundwater. 

Streams

For this study, water-quality data from the UYRW database were compiled for 211 stream sites from January 1975 

through September 2009. A total of 176 site locations were 

unique; some stream sites from different agencies had the 

same physical location (fig. 3, appendix 3). Site names in 

appendix 3 are from the UYRW water-quality database; site 

names used in the body of this report are shorter versions 

of those in appendix 3. Because streams in the UYRW can 

have distinct water-quality characteristics based on location in the watershed, the watershed was divided into six 

subwatersheds for data analysis: Yampa River and tributaries upstream from Chuck Lewis State Wildlife Area (Yampa 

River subwatershed 1), Yampa River and tributaries from 

Chuck Lewis State Wildlife Area to Elk River confluence 

(Yampa River subwatershed 2), Elk River and tributaries 

(Elk River subwatershed), Yampa River and tributaries from 

Elk River confluence to Town of Hayden (Yampa River 

subwatershed 3), Yampa River and tributaries from Town 

of Hayden to Elkhead Creek confluence (Yampa River 

subwatershed 4), and Elkhead Creek and tributaries (Elkhead 

Creek subwatershed) (fig. 1). The Yampa River subwatershed 

3 contains a large portion of the Yampa coal field that is in the 

UYRW (fig. 1).

For the UYRW and each subwatershed, the number of 

stream sites and number of samples with water-quality data 

for 1975 through 2009 are summarized in table 6. Counts are 

included for physical properties and chemical constituents 

discussed in this report. The greatest number of sites sampled 

are in the Yampa River subwatershed 1, and the fewest are 

in the Elkhead Creek subwatershed. About 29 percent (62 of 

211) of the sites are main-stem Yampa River sites. No sites 

were sampled in a large area in the northern one-third of the 

watershed or in some areas in the southern part of the watershed (fig. 3).

A total of 5,861 samples were collected from streams 

in the UYRW (table 6). Most samples have data for physical 

properties (97 percent) and streamflow (63 percent). Fewer 

data are available for dissolved solids (30 percent), major 

ions (33 percent), nutrients (37 percent), and trace elements 

(41 percent). The greatest number of samples was collected in 

Yampa River subwatershed 1 and the fewest in Yampa River 

subwatershed 4. Data were collected every year at only one 

site, Yampa River at Steamboat Springs (site 153), in Yampa 

River subwatershed 2 (appendix 3). The largest yearly gaps in 

data collection occurred in Yampa River subwatershed 4. For 

the UYRW and most subwatersheds, more samples were collected from May through July than in other months of the year. 

About 13 percent (27 of 211) of the sites had data for more 

than 50 samples; almost one-half (96 of 211) had data for 5 or 

fewer samples. Because of this large difference in sampling 

frequency at some sites, some results may be biased by data 

for sites with a high sample count (appendix 3). The CDPHE 

has an active sampling program, but the CDPHE data in 

STORET and in the UYRW water-quality database were only 

available through 2007.

Physical Properties

Physical properties analyzed for this study include specific conductance, pH, water temperature, dissolved oxygen, 

hardness, and acid neutralizing capacity (ANC). These data 

are summarized in table 8. A total of 5,660 samples from 

209 stream sites have data for physical properties from 1975 

through 2009 (table 6). The greatest number of samples analyzed for physical properties was collected during the 1990s. 

The greatest number of samples with data for physical properties were collected in Yampa River subwatershed 1, and the 

fewest were in Yampa River subwatershed 4.

Specific conductance is the ability of a substance to 

conduct an electric current (Hem, 1992). In water, it is proportional to the concentration of major dissolved constituents 

(bicarbonate, calcium, chloride, fluoride, magnesium, potassium, silica, sodium, and sulfate). The weathering of minerals 

in soil and bedrock is a primary source of major dissolved 

constituents to water. Atmospheric deposition can be a substantial source of dissolved chloride and sulfate particularly 

in areas with crystalline bedrock, which typically has low 

chlorine and sulfur content (Mast, 2007). 

Specific conductance in the UYRW was measured in 

4,305 samples from 1975 through 2009 and ranged from 2 to 

10,000 microsiemens per centimeter at 25° Celsius (μS/cm) 

with a median of 315 μS/cm (table 8). Lower specific conductance values (less than 200 μS/cm) were most common in the 
Water-Quality Assessment 19

Table 6. Number of stream sites and samples with water-quality data for the Upper Yampa River watershed and subwatersheds, Colorado, by physical properties or constituent group,1975 through 2009.[No., number; --, no data]

Physical properties 

or constituent group

Upper Yampa

River watershed

Subwatershed

Yampa River and tributaries 

upstream from Chuck Lewis 

State Wildlife Area

(Yampa River

subwatershed 1)

Yampa River and tributaries 

from Chuck Lewis State 

Wildlife Area to 

Elk River confluence

(Yampa River

subwatershed 2)

Elk River

and tributaries

(Elk River

subwatershed)

Yampa River and

tributaries from 

Elk River confluence

to Town of Hayden

(Yampa River

subwatershed 3)

Yampa River and

tributaries from Town 

of Hayden to Elkhead 

Creek confluence

(Yampa River

subwatershed 4)

Elkhead Creek

and tributaries

(Elkhead Creek

subwatershed)

No. of

sites

No. of

samples

No. of

sites

No. of

samples

No. of

sites

No. of

samples

No. of

sites

No. of

samples

No. of

sites

No. of

samples

No. of

sites

No. of

samples

No. of

sites

No. of

samples

Physical properties 209 5,660 55 1,932 52 1,063 23 620 49 1,358 16 204 13 483Streamflow (instantaneous) 139 3,684 35 801 35 795 15 467 35 1,060 11 137 8 424Dissolved solids 110 1,743 28 429 13 166 17 200 33 647 10 101 9 200Major ions 130 1,921 28 473 26 220 17 220 39 697 11 106 8 205Nutrients 164 2,162 33 538 44 302 21 222 46 756 12 128 8 216Trace elements 145 2,427 42 1,022 25 253 19 193 39 708 11 156 9 95Uranium 14 51 4 21 1 4 4 12 4 13 1 1 -- --Coliform bacteria 89 432 20 108 33 175 8 36 18 32 4 12 6 69Suspended sediment 65 1,079 17 261 14 66 10 101 12 399 5 92 7 160Total number of sites and samples 211 5,861 55 1,971 52 1,097 23 629 51 1,452 16 225 14 487
20 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Table 7. Period of water-quality record and number of water-quality samples collected per year from streams, by physical properties 

or constituent group, Upper Yampa River watershed and subwatersheds, Colorado, 1975 through 2009.—Continued

[--, no data]

Physical properties 

or constituent group

Number of water-quality samples collected

1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991

Upper Yampa River watershed

Physical properties 194 231 76 63 103 137 177 145 125 47 93 169 159 137 186 170 280

Streamflow, instantaneous 118 193 26 49 59 103 133 77 63 29 73 149 145 123 171 143 162

Dissolved solids 45 52 37 44 67 88 146 60 76 37 62 63 41 36 28 17 33

Major ions 50 56 37 46 67 89 148 61 77 38 63 64 41 36 32 15 34

Nutrients 137 156 36 46 64 109 146 79 76 38 63 64 41 35 46 27 37

Trace elements 82 101 36 47 77 109 88 95 59 37 51 52 33 32 22 22 79

Uranium -- -- -- -- 8 -- 8 6 4 -- -- -- -- -- -- -- --

Coliform bacteria 56 69 -- -- -- -- -- -- -- -- -- -- -- -- 18 8 19

Suspended sediment 42 137 23 45 57 98 69 65 37 13 29 69 42 39 34 19 32

Yampa River and tributaries upstream from Chuck Lewis State Wildlife Area

(Yampa River subwatershed 1)

Physical properties 47 40 16 10 27 14 22 14 14 14 22 54 49 48 47 55 124

Streamflow, instantaneous 24 23 -- 1 2 7 -- -- -- 2 9 45 41 41 38 38 49

Dissolved solids 10 9 6 3 13 12 19 11 11 14 19 20 22 20 16 8 17

Major ions 10 9 6 4 10 12 20 11 11 14 19 21 22 20 16 7 17

Nutrients 21 27 6 4 10 12 20 11 12 14 19 21 22 19 30 18 25

Trace elements 20 17 6 4 14 11 13 11 11 13 14 16 15 16 16 17 44

Uranium -- -- -- -- 4 -- 4 3 3 -- -- -- -- -- -- -- --

Coliform bacteria 15 15 -- -- -- -- -- -- -- -- -- -- -- -- 18 8 14

Suspended sediment 17 21 -- 6 13 -- -- -- -- -- -- 42 39 39 28 16 25

Yampa River and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence

(Yampa River subwatershed 2)

Physical properties 47 75 9 6 5 7 10 31 42 10 20 55 49 26 59 31 56

Streamflow, instantaneous 29 46 -- -- -- -- 5 6 19 10 19 52 49 26 59 32 46

Dissolved solids 2 -- -- -- -- -- 5 3 15 5 10 8 1 -- 1 -- 5

Major ions 2 1 -- -- -- -- 5 3 16 6 11 8 1 -- 5 -- 5

Nutrients 31 54 -- -- -- -- 5 5 14 6 11 8 1 -- 5 -- 5

Trace elements 6 11 -- -- -- -- -- 6 12 6 4 1 -- -- -- -- 13

Uranium -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

Coliform bacteria 21 38 -- -- -- -- -- -- -- -- -- -- -- -- -- -- 5

Suspended sediment 8 22 -- -- -- -- -- 6 12 3 5 1 -- -- 5 -- 4

Elk River and tributaries

(Elk River subwatershed)

Physical properties 16 23 10 2 7 11 13 12 9 1 2 6 8 15 29 36 30

Streamflow, instantaneous 11 17 1 -- -- -- -- -- 4 1 2 6 8 15 29 36 31

Dissolved solids 4 6 -- -- 4 6 6 3 4 -- -- -- -- -- -- 3 3

Major ions 4 6 -- -- 4 6 6 3 4 -- -- -- -- -- -- 3 4

Nutrients 10 9 -- -- 4 6 6 3 4 -- -- -- -- -- -- 3 4

Trace elements 8 6 -- -- 4 6 6 3 -- -- -- -- -- -- -- 2 2

Uranium -- -- -- -- 2 -- 2 1 -- -- -- -- -- -- -- -- --

Coliform bacteria 5 11 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

Suspended sediment 6 17 1 -- -- -- -- -- -- -- -- -- -- -- -- 3 3

Yampa River and tributaries from Elk River confluence to Town of Hayden

(Yampa River subwatershed 3)

Physical properties 68 72 36 35 48 68 90 65 52 21 47 46 43 41 40 35 44

Streamflow, instantaneous 43 91 25 32 47 66 83 57 37 15 41 38 37 34 34 28 26

Dissolved solids 25 34 31 32 39 46 81 42 42 18 33 35 18 16 11 6 8

Major ions 30 36 31 32 43 47 82 43 42 18 33 35 18 16 11 5 8

Nutrients 64 57 30 32 40 58 80 54 42 18 33 35 18 16 11 6 3

Trace elements 41 57 30 33 47 58 47 63 36 18 33 35 18 16 6 3 3

Uranium -- -- -- -- 2 -- 2 2 1 -- -- -- -- -- -- -- --

Coliform bacteria 11 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

Suspended sediment 7 64 22 29 34 64 44 46 25 10 24 26 3 -- 1 -- --
Water-Quality Assessment 21

Table 7. Period of water-quality record and number of water-quality samples collected per year from streams, by physical properties 

or constituent group, Upper Yampa River watershed and subwatersheds, Colorado, 1975 through 2009.—Continued

[--, no data]

Physical properties 

or constituent group

Number of water-quality samples collected

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

Upper Yampa River watershed

Physical properties 360 285 296 262 242 263 182 219 176 298 159 118 97 70 55 63 20 3

Streamflow, instantaneous 233 150 140 161 126 132 137 187 155 119 90 91 76 56 4 4 4 3

Dissolved solids 25 14 9 18 69 124 41 88 52 198 88 46 19 3 7 4 4 2

Major ions 25 14 9 18 69 124 41 89 61 199 89 49 31 8 55 63 20 3

Nutrients 31 11 13 19 69 126 41 89 61 199 89 42 23 8 55 63 20 3

Trace elements 122 106 124 108 127 139 65 61 47 184 87 56 31 8 55 63 20 2

Uranium -- -- -- -- -- -- -- -- -- -- -- 5 17 -- 3 -- -- --

Coliform bacteria 18 4 4 2 7 10 9 22 14 63 45 10 3 4 4 20 20 3

Suspended sediment 19 -- -- 8 22 28 24 54 23 14 12 25 -- -- -- -- -- --

Yampa River and tributaries upstream from Chuck Lewis State Wildlife Area

(Yampa River subwatershed 1)

Physical properties 202 173 184 142 101 102 54 51 38 93 60 36 31 15 18 15 -- --

Streamflow, instantaneous 102 50 37 49 30 30 29 33 27 19 21 19 22 13 -- -- -- --

Dissolved solids 10 2 -- -- 12 33 3 11 12 74 35 2 5 -- -- -- -- --

Major ions 10 2 -- -- 12 33 3 11 12 74 35 4 15 -- 18 15 -- --

Nutrients 20 2 -- -- 12 34 3 11 12 74 35 4 7 -- 18 15 -- --

Trace elements 99 93 109 87 61 70 22 22 16 74 43 20 15 -- 18 15 -- --

Uranium -- -- -- -- -- -- -- -- -- -- -- 2 5 -- -- -- -- --

Coliform bacteria 14 -- -- -- -- -- -- 8 -- 7 9 -- -- -- -- -- -- --

Suspended sediment 15 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

Yampa River and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence

(Yampa River subwatershed 2)

Physical properties 60 32 49 42 42 38 38 31 26 31 25 17 19 20 8 24 20 3

Streamflow, instantaneous 57 32 49 42 18 22 27 29 24 17 17 16 16 16 4 4 4 3

Dissolved solids 4 3 -- -- 6 21 5 9 7 18 12 5 5 3 3 4 4 2

Major ions 4 3 -- -- 6 21 5 9 7 18 13 5 7 4 8 24 20 3

Nutrients 4 3 -- -- 6 21 5 9 7 18 13 5 7 4 8 24 20 3

Trace elements 8 3 -- -- 28 20 21 8 5 18 13 5 7 4 8 24 20 2

Uranium -- -- -- -- -- -- -- -- -- -- -- 1 3 -- -- -- -- --

Coliform bacteria 4 3 -- 1 4 4 7 4 15 11 4 3 4 4 20 20 3

Suspended sediment -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

Elk River and tributaries

(Elk River subwatershed)

Physical properties 28 23 14 11 17 31 20 63 44 46 29 38 12 1 9 4 -- --

Streamflow, instantaneous 28 23 14 11 11 15 19 62 44 19 20 30 9 1 -- -- -- --

Dissolved solids 5 4 4 2 11 18 1 36 13 27 11 22 3 -- 4 -- -- --

Major ions 5 4 4 2 11 18 1 37 21 27 11 23 3 -- 9 4 -- --

Nutrients 5 4 4 1 11 19 1 37 21 27 11 16 3 -- 9 4 -- --

Trace elements 2 3 4 2 11 19 1 17 15 27 11 28 3 -- 9 4 -- --

Uranium -- -- -- -- -- -- -- -- -- -- -- 1 3 -- 3 -- -- --

Coliform bacteria -- -- -- -- 1 3 -- -- -- 10 6 -- -- -- -- -- -- --

Suspended sediment 4 -- -- -- -- -- -- 35 19 -- -- 13 -- -- -- -- -- --

Yampa River and tributaries from Elk River confluence to Town of Hayden

(Yampa River subwatershed 3)

Physical properties 49 43 35 36 38 59 46 45 32 55 5 1 5 24 18 16 -- --

Streamflow, instantaneous 36 36 28 29 24 31 38 36 29 22 -- -- -- 17 -- -- -- --

Dissolved solids 6 5 5 6 13 28 8 11 4 33 5 1 5 -- -- -- -- --

Major ions 6 5 5 6 13 28 8 11 4 33 5 1 5 3 18 16 -- --

Nutrients 2 1 5 6 13 28 8 11 4 33 5 1 5 3 18 16 -- --

Trace elements 2 1 5 6 13 28 16 9 3 33 5 1 5 3 18 16 -- --

Uranium -- -- -- -- -- -- -- -- -- -- -- 1 5 -- -- -- -- --

Coliform bacteria -- -- -- -- -- -- 1 3 2 12 3 -- -- -- -- -- -- --

Suspended sediment -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
22 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Elk River subwatershed and headwater tributaries in Yampa 

River subwatershed 2 (fig. 6A). The underlying geology of 

these two subwatersheds is composed mostly of igneous and 

metamorphic rocks (fig. 5) that are resistant to weathering. 

Less weathering results in fewer dissolved constituents and 

low specific conductance in stream water. Specific conductance values greater than 1,000 μS/cm were most common in 

Yampa River subwatersheds 3 and 4 (fig. 6A). Cretaceous-age 

sedimentary rocks underlying these subwatersheds (fig. 5) are 

susceptible to weathering, which results in an increase in dissolved constituents and specific conductance in stream water. 

Although the Elkhead Creek subwatershed is also underlain by sedimentary rocks, the median specific conductance 

(305 μS/cm) for this subwatershed is much lower than that for 

Yampa River subwatersheds 3 and 4 (802 and 1,008 μS/cm, 

respectively). Differences in sedimentary rocks underlying 

the subwatersheds could account for some of the difference 

in specific conductance values (fig. 5). Also, processes in 

Elkhead Creek Reservoir could reduce specific conductance 

at stream sites (sites 41 and 42) just downstream from the 

reservoir outlet from what would occur naturally. Median 

specific conductance for these sites was about 100 μS/cm 

lower than the median value for site 40, upstream from the 

reservoir. Throughout the UYRW, specific conductance typically was lowest during snowmelt runoff when dilute waters 

dominate streamflow and were greater during most other times 

of the year when groundwater dominates streamflow. This is 

illustrated by the monthly distribution of specific conductance 

values measured at Yampa River at Milner (site 151) (fig. 7A). 

This pattern is present for many dissolved constituents 

in water.

Specific conductance data for three sites met the statistical requirements for trends testing (see “Temporal Trend 

Analysis” subsection). A statistically significant (p-value 

0.03) trend in a downward direction was identified for specific 

conductance at Yampa River at Steamboat Springs (site 153) 

for 1997 through 2008 (table 9). The rate of change in specific 

conductance was small, less than 3 percent per year (magnitude about 6 μS/cm per year). The median specific conductance at the site was 264 μS/cm.

The pH represents the effective concentration (activity) of hydrogen ions in water and is measured as the negative logarithm of the hydrogen ion activity (Hem, 1992). 

Pure water has a pH of 7. A value lower than 7 is considered 

acidic, and a value higher than 7 is considered alkaline or 

basic. Stream water not influenced by human activities 

typically has a pH that ranges from 6.5 to 8.5. The pH of a 

water-quality sample can be affected by biological activity in a stream, geology, precipitation, and human activities. 

Diurnal fluctuations in pH (lowest in the morning, highest 

in the late afternoon) result when algae take up dissolved 

carbon dioxide through photosynthesis during the day, which 

decreases the concentration of carbonic acid dissolved in 

water (increasing pH), and release carbon dioxide through 

respiration at night (decreasing pH) (Hem, 1992). Values 

of pH decrease in the presence of sulfide-bearing minerals (including pyrite) in rocks and soils as water and oxygen react with sulfur to form sulfuric acid. This can occur 

naturally in areas with mineralized bedrock or in areas with 

hard-rock mining. Hard-rock and coal mining can result in 

acidic drainage to a stream. The solubility and biological 

Table 7. Period of water-quality record and number of water-quality samples collected per year from streams, by physical properties 

or constituent group, Upper Yampa River watershed and subwatersheds, Colorado, 1975 through 2009.—Continued

[--, no data]

Physical properties 

or constituent group

Number of water-quality samples collected

1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991

Yampa River and tributaries from Town of Hayden to Elkhead Creek confluence

(Yampa River subwatershed 4)

Physical properties 8 3 -- 9 11 35 38 13 -- -- -- -- -- -- -- 4 17

Streamflow, instantaneous 4 3 -- 15 10 37 38 14 -- -- -- -- -- -- -- -- --

Dissolved solids 1 -- -- 8 9 24 35 1 -- -- -- -- -- -- -- -- --

Major ions 1 -- -- 9 10 24 35 1 -- -- -- -- -- -- -- -- --

Nutrients 6 3 -- 9 10 33 35 6 -- -- -- -- -- -- -- -- --

Trace elements 2 3 -- 9 10 34 22 12 -- -- -- -- -- -- -- -- 17

Uranium -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

Coliform bacteria 2 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

Suspended sediment -- -- -- 10 10 34 25 13 -- -- -- -- -- -- -- -- --

Elkhead Creek and tributaries

(Elkhead Creek subwatershed)

Physical properties 8 18 5 1 5 2 4 10 8 1 2 8 10 7 11 9 9

Streamflow, instantaneous 7 13 -- 1 -- -- -- -- 3 1 2 8 10 7 11 9 10

Dissolved solids 3 3 -- 1 2 -- -- -- 4 -- -- -- -- -- -- -- --

Major ions 3 4 -- 1 -- -- -- -- 4 -- -- -- -- -- -- -- --

Nutrients 5 6 -- 1 -- -- -- -- 4 -- -- -- -- -- -- -- --

Trace elements 5 7 -- 1 2 -- -- -- -- -- -- -- -- -- -- -- --

Coliform bacteria 2 5 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

Suspended sediment 4 13 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
Water-Quality Assessment 23

availability of nutrients and trace elements and some chemical processes are pH dependent. A pH less than 4 and greater 

than 10 can affect the survivability of aquatic organisms 

(http://extension.usu.edu/files/publications/publication/nr_

wq_2005-19.pdf, accessed June 2012).

For the UYRW, pH was measured in 3,140 samples from 

1975 through 2009 at 184 sites. Values ranged from 2.1 to 

9.8, and the median was 8.1 (table 8). Median pH was highest in the Yampa River subwatershed 1 and Elkhead Creek 

subwatershed (8.3 and 8.2, respectively) and lowest (7.6) in 

the Elk River subwatershed (fig. 6B). About 84 percent of pH 

values were between 6.5 and 8.5. Individual values greater 

than 8.5 were more common than individual values less than 

6.5. Many high values occurred during summer afternoons. 

Values greater than 8.5 also were more common in samples 

from Yampa River subwatershed 3 than from the other subwatersheds. Fewer than 3 percent of sites had pH values that 

were not in attainment of the CDPHE aquatic-life standard for 

pH (fig. 8, table 10). These data were collected at four sites 

in Yampa River subwatershed 2 and one site in the Elk River 

subwatershed. Data for the four sites with pH not in attainment 

of the 6.5 standard were collected before 1988; current (2010) 

data were not available to evaluate pH at these sites. Nonattainment of the 9.0 standard for Yampa River above Elk 

River (site 145) was based on the three values collected at 

the site; collections dates were from 1999 through 2002. For 

pH and other water-quality constituents, the Yampa River at 

Steamboat Springs (site 153) was the only site with data that 

met the requirements for temporal trend analysis. No statistically significant (p-value 0.41) trend in pH was identified at 

the site for the period 1997 through 2008 (table 9).

Water temperature is an important property that controls 

biological and chemical reaction rates. Temperature often 

directly affects dissolved oxygen levels and life cycles of 

aquatic organisms (Hem, 1992). Water-temperature data in 

the UYRW database are instantaneous measurements made 

when a water-quality sample was collected. Water temperature was measured for 5,187 samples from 1975 through 

2009 and ranged from –3 to 30.4 °C with a median of 7.5 °C 

(table 8). The Elk River subwatershed had the lowest median 

water temperature and the Yampa River subwatershed 4 had 

the highest, which are likely due to differences in the altitude 

and climate of sites where water temperatures were measured. 

Most (41 of 55) temperature values less than 0 °C were measured from November through February. All values greater 

than 25 °C were measured from June through August. Median 

values of water temperature for main-stem Yampa River sites 

were highest for Yampa River subwatersheds 3 and 4 and 

lowest for Yampa River subwatersheds 1 and 2 because of the 

inflow of streams in the latter two subwatersheds that drain 

high altitude, colder areas of the UYRW. The Yampa River at 

Steamboat Springs (site 153) was the only site with sufficient 

instantaneous water temperature data for temporal trend analysis; a statistically significant trend was not identified for 1997 

through 2008 (table 9).

The Yampa River at Steamboat Springs site (site 153) also 

was the only site with a continuous record of water temperature; 

measurements were made at 15-minute intervals for most days 

from July 26, 2002, through April 13, 2005. Values greater than 

the June through September acute DM and chronic MWAT 

cold-water aquatic-life standards at this site occurred most 

often from mid-July through August during 2002, 2003, and 

Table 7. Period of water-quality record and number of water-quality samples collected per year from streams, by physical properties 

or constituent group, Upper Yampa River watershed and subwatersheds, Colorado, 1975 through 2009.—Continued

[--, no data]

Physical properties 

or constituent group

Number of water-quality samples collected

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

Yampa River and tributaries from Town of Hayden to Elkhead Creek confluence

(Yampa River subwatershed 4)

Physical properties 11 5 2 1 1 -- -- -- 2 18 6 -- 12 6 -- 2 -- --

Streamflow, instantaneous -- -- -- -- -- -- -- -- -- -- -- -- 11 5 -- -- -- --

Dissolved solids -- -- -- -- -- -- -- -- 1 15 -- 6 1 -- -- -- -- --

Major ions -- -- -- -- -- -- -- -- 1 15 6 -- 1 1 -- 2 -- --

Nutrients -- -- -- -- -- -- -- -- 1 15 6 -- 1 -- 1 2 -- --

Trace elements 11 5 2 1 1 -- -- -- 1 16 6 -- 1 1 -- 2 -- --

Uranium -- -- -- -- -- -- -- -- -- -- -- -- 1 -- -- -- -- --

Coliform bacteria -- -- -- -- -- -- -- -- -- 5 5 -- -- -- -- -- -- --

Suspended sediment -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

Elkhead Creek and tributaries

(Elkhead Creek subwatershed)

Physical properties 10 9 12 30 43 33 24 29 34 55 34 26 18 4 2 2 -- --

Streamflow, instantaneous 10 9 12 30 43 34 24 27 31 42 32 26 18 4 -- -- -- --

Dissolved solids -- -- -- 10 27 24 24 21 15 31 19 16 -- -- -- -- -- --

Major ions -- -- -- 10 27 24 24 21 16 32 19 16 -- -- 2 2 -- --

Nutrients -- 1 4 12 27 24 24 21 16 32 19 16 -- -- 2 2 -- --

Trace elements -- 1 4 12 13 2 5 5 7 16 9 2 -- -- 2 2 -- --

Coliform bacteria -- 1 4 2 5 3 4 4 8 14 11 6 -- -- -- -- -- --

Suspended sediment -- -- -- 8 22 28 24 19 4 14 12 12 -- -- -- -- -- --
24 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Table 8. Summary statistics for selected physical property water-quality data and Colorado Department of Public Health and 

Environment in-stream water-quality standards for stream sampling sites in the Upper Yampa River watershed and subwatersheds, 

Colorado, 1975 through 2009.—Continued

[No., number; μS/cm; microsiemens per centimeter at 25 degrees Celsius; --, no water-quality standard; °C, degrees Celsius; mg/L, milligrams per liter; CaCO3, 

calcium carbonate. Number of significant figures for individual constituents may vary because data are from different sources and analytical periods. Waterquality standards are from Colorado Department of Public Health and Environment (2009a, 2010). See table 10 for sites in the Upper Yampa River watershed 

and subwatersheds with data for physical properties exceeding in-stream water-quality standards. Descriptions of stream segments are in Colorado Department 

of Public Health and Environment (2010)]

Physical property

(reporting units)

No. of

sites

No. of

samples

No. of

censored

values1

Minimum

value2

Median

value

Maximum

value

In-stream

water-quality

standard

No. of sites with

data not in attainment

of standard

Upper Yampa River watershed

Specific conductance (μS/cm) 191 4,305 33 2 315 10,000 -- --

pH (standard units) 184 3,140 0 2.1 8.1 9.8 6.5–9.0 5

Water temperature (°C) 191 5,187 0 –3 7.5 30.4 (3) 41

Oxygen, dissolved (mg/L) 171 2,797 0 1.2 9.8 17.8 55.0, 6.0

(minima)

2

Hardness (mg/L as CaCO3) 142 2,434 2 4 162 4,000 -- --

Acid neutralizing capacity

(mg/L as CaCO3)

134 2,244 1 2 136 660 -- --

Yampa River and tributaries upstream from Chuck Lewis State Wildlife Area

(Yampa River subwatershed 1; stream segments 2a, 2c, 3, 4, 5, 6, 7)

Specific conductance (μS/cm) 46 958 0 29 425 1,179 -- --

pH (standard units) 51 1,171 0 6.3 8.3 9.4 6.5–9.0 0

Water temperature (°C) 50 1,582 0 –3 8.0 28.0 (

3

) --4

Oxygen, dissolved (mg/L) 51 1,293 0 1.2 9.8 15.0 6.0

(minima)

2

Hardness (mg/L as CaCO3) 41 1,018 0 25 190 1,550 -- --

Acid neutralizing capacity 

(mg/L as CaCO3)

41 989 0 4 152 420 -- --

Yampa River and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence

(Yampa River subwatershed 2; stream segments 2c, 3, 20a)

Specific conductance (μS/cm) 48 968 30 2 57 750 -- --

pH (standard units) 39 288 0 5.6 7.8 9.7 6.5–9.0 4

Water temperature (°C) 42 1,003 0 –0.2 6.0 26.6 (

3

) 41

Oxygen, dissolved (mg/L) 38 299 0 4.0 10.0 17.8 6.0

(minima)

0

Hardness (mg/L as CaCO3) 26 218 1 4.3 48 320 -- --

Acid neutralizing capacity 

(mg/L as CaCO3)

21 187 0 2 60 240 -- --

Elk River and tributaries

(Elk River subwatershed; stream segments 8, 20a)

Specific conductance (μS/cm) 22 570 3 16 80 750 -- --

pH (standard units) 22 233 0 6.0 7.6 9.4 6.5–9.0 1

Water temperature (°C) 23 613 0 –0.3 5.7 25.5 (

3

) --4

Oxygen, dissolved (mg/L) 22 200 0 6.9 9.9 13.8 6.0

(minima)

0

Hardness (mg/L as CaCO3) 17 209 1 4 21 120 -- --

Acid neutralizing capacity 

(mg/L as CaCO3)

15 133 1 4 30 86 -- --

Yampa River and tributaries from Elk River confluence to Town of Hayden

(Yampa River subwatershed 3; stream segments 2c, 11, 12, 13a, 13b, 13c, 13e, 13f, 20a)

Specific conductance (μS/cm) 48 1,196 0 49 802 6,360 -- --

pH (standard units) 48 1,105 0 2.1 8.1 9.8 6.5–9.0 0

Water temperature (°C) 48 1,314 0 –0.2 8.9 28.6 (

3

) --4

Oxygen, dissolved (mg/L) 38 668 0 3.0 9.7 16.0 55.0, 6.0

(minima)

0

Hardness (mg/L as CaCO3) 37 679 0 20 260 3,000 -- --

Acid neutralizing capacity 

(mg/L as CaCO3)

37 667 0 8.2 162 660 -- --
Water-Quality Assessment 25

2004; and a few exceedances occurred during early September 

(figs. 9A, 9B). The June through September chronic MWAT 

was exceeded on the greatest number of sample days (table 11). 

Although some water temperature values were greater than the 

June through September standards, this does not necessarily 

mean that the values were not in attainment of the standards for 

regulatory purposes because streamflow was lower than normal 

during the measuring period. Water temperature may exceed 

the standards when streamflow is less than critical low flows 

calculated from CDPHE formulas (Colorado Department of 

Public Health and Environment, 2009a). Critical low flows were 

not calculated for this study. Water temperatures also did not 

meet the October through May acute DM and chronic MWAT 

cold-water standards, primarily during October (figs. 9C, 9D; 

table 11). In total, the DM and MWAT standards were exceeded 

on 16 and 26 percent of all sample days, respectively, possibly due to reduced streamflow during drought conditions and 

from upstream hydrologic modifications, streams depths that 

are less than those normally observed during summer, and (or) 

changes in the river channel. The stream segment Yampa River 

from Oak Creek to Elkhead Creek, including Yampa River at 

Steamboat Springs (site 153), is on the CDPHE 2012 monitoring and evaluation list for water temperature (table 5) (Colorado 

Department of Public Health and Environment, 2012). Increases 

in water temperature on the main stem of the Yampa River 

during summer in combination with low streamflow and low 

dissolved oxygen concentrations can result in reduced habitat 

availability for fish species and can create less than optimal 

resource conditions.

Dissolved oxygen is the measurement of the oxygen in 

water that is available to fish and aquatic life. It varies with 

temperature, altitude, and water depth and is affected by 

many factors, such as photosynthesis, respiration activity, and 

inputs from point and nonpoint sources. Dissolved oxygen 

often has seasonal as well as diurnal variations. Concentrations are typically higher when water temperatures are colder 

(Hem, 1992).

Table 8. Summary statistics for selected physical property water-quality data and Colorado Department of Public Health and 

Environment in-stream water-quality standards for stream sampling sites in the Upper Yampa River watershed and subwatersheds, 

Colorado, 1975 through 2009.—Continued

[No., number; μS/cm; microsiemens per centimeter at 25 degrees Celsius; --, no water-quality standard; °C, degrees Celsius; mg/L, milligrams per liter; CaCO3, 

calcium carbonate. Number of significant figures for individual constituents may vary because data are from different sources and analytical periods. Waterquality standards are from Colorado Department of Public Health and Environment (2009a, 2010). See table 10 for sites in the Upper Yampa River watershed 

and subwatersheds with data for physical properties exceeding in-stream water-quality standards. Descriptions of stream segments are in Colorado Department 

of Public Health and Environment (2010)]

Physical property

(reporting units)

No. of

sites

No. of

samples

No. of

censored

values1

Minimum

value2

Median

value

Maximum

value

In-stream

water-quality

standard

No. of sites with

data not in attainment

of standard

Yampa River and tributaries from Town of Hayden to Elkhead Creek confluence

(Yampa River subwatershed 4; stream segments 2c, 12, 13d)

Specific conductance (μS/cm) 15 150 0 72.2 1,008 10,000 -- --

pH (standard units) 13 122 0 6.5 8.0 8.8 6.5–9.0 0

Water temperature (°C) 16 200 0 –0.3 9.5 25.2 (3) --4

Oxygen, dissolved (mg/L) 11 123 0 4.5 9.2 14.0 55.0, 6.0

(minima)

0

Hardness (mg/L as CaCO3) 11 104 0 23 540 4,000 -- --

Acid neutralizing capacity 

(mg/L as CaCO3)

12 145 0 12 230 590 -- --

Elkhead Creek and tributaries

(Elkhead Creek subwatershed; stream segments 14, 15, 20b)

Specific conductance (μS/cm) 12 463 0 100 305 912 -- --

pH (standard units) 11 221 0 7.3 8.2 9.5 6.5–9.0 0

Water temperature (°C) 12 475 0 –0.1 8.7 30.4 (3) --4

Oxygen, dissolved (mg/L) 11 214 0 4.7 10.1 14.5 55.0, 6.0

(minima)

0

Hardness (mg/L as CaCO3) 10 206 0 47.4 128 331 -- --

Acid neutralizing capacity 

(mg/L as CaCO3)

8 123 0 48.6 114 219 -- --

1

Censored values can be expressed as values less than the laboratory reporting level.

2

For some constituents with censored data, the minimum censored value is greater than the minimum detected value that is shown.

3

See appendix 2 for Colorado Department of Public Health and Environment temperature standards for cold- and warm-water streams.

4

Only one site, Yampa River at Steamboat Springs (site 153) in stream segment 2c, had data for the continuous monitoring of temperature. The temperature 

standards only were applied to temperature data for this site. See figure 9 and table 11 for exceedances of the standards.

5

Water-quality standard varies by stream segment. See Colorado Department of Public Health and Environment (2010).
26 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Figure 6. Distribution of (A) specific conductance, (B), pH, (C) acid neutralizing capacity, and concentrations of 

(D) dissolved sulfate and (E) dissolved manganese in stream water, by subwatershed, Upper Yampa River watershed, 

Colorado, 1975 through 2009. 

73 125 128 429 80 185

10,000

1,000

100

10

1

0.1

D

E

400

397

300

200

100

0

184 156 394 109 88

Concentration of dissolved sulfate,

in milligrams per liter

Concentration of

dissolved manganese,

in micrograms per liter

Specific conductance,

in microsiemens per centimeter

at 25 degrees Celsius

pH,

in standard units

Acid neutralizing capacity,

in milligrams per liter

5,000

4,000

3,000

2,000

1,000

0

A

12

11

10

9

8

7

6

5

4

3

2

700

600

500

400

300

200

100

0

958 968 570 1,196 150 463

1,171 288 233 1,105 122 221

989 187 133 667 145 123

CDPHE water-quality

standard range for

aquatic-life protection CDPHE 

water- quality

standard

Subwatershed

Subwatershed

Yampa River

subwatershed 1

Yampa River

subwatershed 2

Yampa River

subwatershed 3

Yampa River

subwatershed 4

Elk River

subwatershed

Elkhead Creek

subwatershed

Yampa River

subwatershed 1

Yampa River

subwatershed 2

Yampa River

subwatershed 3

Yampa River

subwatershed 4

Elk River

subwatershed

Elkhead Creek

subwatershed

B

C

Number of samples

Colorado Department of Public

 Health and Environment

Data values outside the 10th 

 and 90th percentiles

123

Percentiles

90th

75th

25th

50th

10th

EXPLANATION

CDPHE
Water-Quality Assessment 27

Figure 7. Distribution of (A) specific conductance, and concentrations of (B) unfiltered sulfate, (C) unfiltered total phosphorus, and 

(D) total recoverable iron at Yampa River at Milner (site 151), by month, Upper Yampa River watershed, Colorado, 1975 through 2007.

Percentiles

90th

75th

25th

50th

10th

EXPLANATION

Number of samples

Data less than detection limit

10

9 10 13 14 10

0

500

1,000

1,500

2,000

2,500

Concentration of

total recoverable iron, in micrograms per liter

Colorado Department of Public Health and Environment

 chronic water-quality standard for aquatic-life protection

Month

0.00

0.05

0.10

0.15

0.20

0.25

0.30

Concentration of

unfiltered total phosphorus,

in milligrams per liter

C

D

0

10

20

30

40

50

60

Concentration of unfiltered sulfate,

in milligrams per liter

B

Specific conductance,

in microsiemens per centimeter

at 25 degrees Celsius

400

300

200

100

0

A 11 10 9 14 9 15 10

16 10 17 12 16 11 15 12 13 12 15 14

14 10 18 14 14 10 13 11 14 11 15 15

16 9 17 12 14 10 14 10 11 12 14 13

U.S. Environmental Protection Agency

recommended concentration

Jan. Feb. March April May June July Aug. Sept. Oct. Nov. Dec.
28 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009 Table 9. Results of Seasonal Kendall trend analysis for selected physical properties or water-quality constituents at three stream sites in the Upper Yampa River watershed, Colorado, 1997 through 2008. [No., number; p-value, significance of trend; μS/cm; microsiemens per centimeter at 25 degrees Celsius; --, trend not statistically significant; °C, degrees Celsius; mg/L, milligrams per liter; CaCO3, calcium carbonate; P, phosphorus; μg/L, micrograms per liter; col/100 mL, colonies per 100 milliliters. Results that are statistically significant are shown in bold type. See figure 3 and appendix 3 for location of sites and additional site information] Physical property or constituent (reporting units) Period of water-quality record (calendar year) No. of samples/ No. of censored values Flow adjustment p-value Trend direction Trend slope Magnitude of trend slope (percent/year) Magnitude of trend slope (units/year) Median value Yampa River above Stagecoach Reservoir (site 147 in Yampa River subwatershed 1, Yampa River and tributaries upstream from Chuck Lewis State Wildlife Area) Specific conductance (μS/cm) 1990–2003 167/0 Yes 0.77 None -- -- -- 452 Elk River near Milner, CO (site 33 in Elk River subwatershed, Elk River and tributaries) Specific conductance (μS/cm) 1990–2003 162/0 Yes 0.08 None -- -- -- 122 Yampa River at Steamboat Springs (site 153 in Yampa River subwatershed 2, Yampa River and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence) Specific conductance (μS/cm) 1997–2008 127/0 Yes 0.03 Down –0.028 –2.7 –6.0 264 pH (standard units) 1997–2008 55/0 Yes 0.41 -- -- -- -- 8.2 Water temperature (°C) 1997–2008 125/0 Yes 0.17 -- -- -- -- 6.0 Hardness (mg/L as CaCO3

) 1997–2008 49/0 Yes 0.09 -- -- -- -- 116

Dissolved solids (mg/L) 1997–2008 44/0 Yes 0.03 Down –0.030 –3.0 –3.9 153Calcium, dissolved (mg/L) 1997–2008 49/0 Yes 0.07 -- -- -- -- 30.0Magnesium, dissolved (mg/L) 1997–2008 49/0 Yes 0.08 -- -- -- -- 9.84Sodium, dissolved (mg/L) 1997–2008 49/0 Yes 0.40 -- -- -- -- 8.20Potassium, dissolved (mg/L) 1997–2008 49/0 Yes 0.26 -- -- -- -- 1.74Sulfate, dissolved (mg/L) 1997–2008 48/0 Yes 0.06 -- -- -- -- 27.4Chloride, dissolved (mg/L) 1997–2008 48/0 Yes 0.06 -- -- -- -- 3.64Silica, dissolved (mg/L) 1997–2008 48/0 Yes 0.77 -- -- -- -- 9.72Total phosphorous, unfiltered (mg/L as P) 1997–2008 48/3 Yes 0.04 Up 0.031 3.1 0.001 0.036Iron, total recoverable (μg/L) 1997–2008 48/0 Yes 0.53 -- -- -- -- 255Manganese, dissolved (μg/L) 1997–2008 48/0 Yes 0.17 -- -- -- -- 17.4Manganese, total recoverable (μg/L) 1997–2008 48/0 Yes 0.03 Down –0.047 –4.6 –2.6 45.6Escherichia coli (col/100 mL) 1997–2008 47/4 No 0.06 -- -- -- -- 2.7
Water-Quality Assessment 29

Figure 8. Location of water-quality sampling sites with exceedances of Colorado Department of Public Health and 

Environment in-stream water-quality standards for physical properties (pH, water temperature, dissolved oxygen), dissolved 

solids, and unfiltered sulfate and U.S. Environmental Protection Agency recommended concentrations for total phosphorus, 

Upper Yampa River watershed, Colorado, 1975 through 2009.

# #

#

#

#

##

#

#

#

#

#

#

#

#

#

#

# #

#

#

11

17

40

43

153

63 65

66

70

76

81

115

135

138,139,158

140

140

145

147

149 154 163

Base from U.S. Geological Survey digital data,

1:100,000, Universal Transverse Mercator, 

Zone 13 North, North American Datum of 1983

Water-quality standard 

or recommended concentration

0 5 10 MILES

0 5 10 KILOMETERS

166#

Aquatic-life

standard

Water-supply standard 

or recommended 

concentration

pH

Water temperature

Dissolved oxygen

Dissolved solids

Unfiltered total phosphorus

Unfiltered sulfate

EXPLANATION

Streamwater sampling site

 and site number

Sample collected before 1996

Sample collected during and after 1996

Pearl

Lake

Streamboat

Lake

Lake

Elbert

Fish Creek

Reservoir

Lake

Catamount

Yamcolo

Reservoir

Stillwater

Reservoir

Long Lake

Reservoir

Long Lake

Reservoir

Stagecoach

Reservoir

Elk

River

Ma d Creek

Yampa R

Fish CreekFish Creek

Service Creek

Walton CreekWalton Creek

Morrison Creek

Bushy Cr

Yampa Riv er Yampa Riv er

Little

Morrison

Creek

Bear River

Trout Creek

Foidel Cree k

Grassy Cre ek

Fish Creek

Sage Creek

Wolf Cr

YampaRiverYampaRiver

Dry Creek

Elkhead Cr

Elkhead

Reservoir

First CreekFirst Creek

Oak Creek

Lost Dog Cr

Chimney CreekChimney Creek

Yampa River

subwatershed 4

Yampa River

subwatershed 1

Yampa River

subwatershed 3

Yampa River

subwatershed 2

Elk River

Elkhead Creek subwatershed

subwatershed

40°30'

40°15'

40°00'

40°45'

107°15'

107°00'

106°45'

Steamboat

Springs
30 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009 Table 10. Stream water-quality sites with data in exceedance of Colorado Department of Public Health and Environment in-stream water-quality standards for selected physical properties and water-quality constituents and U.S. Environmental Protection Agency recommended concentrations for total phosphorus, Upper Yampa River watershed, Colorado, 1975 through 2009.—Continued [No., number; Min., minimum; Max., maximum; WS, water supply; SMCL, secondary maximum contaminant level; USEPA, U.S. Environmental Protection Agency; <, less than. Subwatershed definitions: Yampa River subwatershed 1, Yampa River and tributaries upstream from Chuck Lewis State Wildlife Area; Yampa River subwatershed 2, Yampa River and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence; Elk River subwatershed, Elk River and tributaries; Yampa River subwatershed 3, Yampa River and tributaries from Elk River confluence to Town of Hayden; Yampa River subwatershed 4, Yampa River and tributaries from Town of Hayden to Elkhead Creek confluence; Elkhead Creek subwatershed, Elkhead Creek and tributaries. Water-quality standards are from Colorado Department of Public Health and Environment (2009a, 2010); standards are for protection of aquatic life, unless otherwise stated. Recommended concentrations for total phosphorus are from U.S. Environmental Protection Agency (2000). Nonattainment of a standard is based on the 15th, 50th, or 85th percentile value shown in the table. See appendix 3 for additional site information. Descriptions of stream segments are in Colorado Department of Public Health and Environment (2010)] Site no. (see figures 8, 12) Site name in Upper Yampa River watershed water-quality database Site identifier Stream segment Subwatershed Period of water-quality record (calendar year) No. of samples No. of censored values1 Min. value Max. value Percentile value (percentile) In-stream water-quality standard or recommended value pH (standard units) 11 BURGESS CREEK AB SKI AREA NR STEAMBOAT SPGS, CO. 402802106471000 3 Yampa River subwatershed 2 1975–76 6 0 6.2 7.4 6.4 (15th) 6.5 53 FISH CREEK NEAR STEAMBOAT SPRINGS, CO 09239000 3 Yampa River subwatershed 2 1975–76 6 0 6.0 6.8 6.0 (15th) 6.5 76 NORTH FORK ELK RIVER NEAR HINMAN PARK, CO. 404620106462200 20a Elk River subwatershed 1975–76 3 0 6.2 7.1 6.4 (15th) 6.5 81 NORTH FORK WALTON CREEK NR RABBIT EARS PASS, CO. 09238300 3 Yampa River subwatershed 2

21975–87 10 0 5.6 8.3 6.4 (15th) 6.5

145 YAMPA RIVER ABV ELK RIVER 402936106565000 2c Yampa River 

subwatershed 2

21999–2002 3 0 9.2 9.2 9.2 (85th) 9.0

Water temperature (degrees Celsius)

153 YAMPA RIVER AT STEAMBOAT 

SPRINGS, CO

09239500 2c Yampa River

subwatershed 2

32002–05 31,802 0 0.0 31.3 --3 --3

Dissolved oxygen (milligrams per liter)

66 LITTLE WHITE SNAKE CK @ HWY 131 12897 4 Yampa River 

subwatershed 1

2001, 

2006–07

4 0 2.2 6.2 3.8 (15th) 6.0 (minima)

70 MARTIN C AB DAM SITE NR OAK 

CREEK, CO

401729106514601 3 Yampa River 

subwatershed 1

1986–88 14 0 5.0 11.6 5.7 (15th) 6.0 (minima)

Dissolved solids (milligrams per liter)4

115 TROUT CK NR. MOUTH 12876 13f Yampa River 

subwatershed 3

21996–2004 17 0 160 680 636 (85th) 500 WS (SMCL)

Sulfate, unfiltered (milligrams per liter)

66 LITTLE WHITE SNAKE CK @ HWY 131 12897 4 Yampa River 

subwatershed 1

2001, 

2006–07

4 0 210 290 285 (85th) 250 WS (SMCL)

115 TROUT CK NR. MOUTH 12876 13f Yampa River 

subwatershed 3

21996–2007 22 0 49 310 298 (85th) 250 WS (SMCL)

Total phosphorus, unfiltered (milligrams per liter)5

17 COW CR. NR STEAMBOAT 

SPRINGS,CO.

402836106550100 3 Yampa River 

subwatershed 2

1982 3 0 0.053 0.921 0.674 (85th) 0.1 (USEPA recommended)

40 ELKHEAD CREEK ABOVE LONG 

GULCH, NEAR HAYDEN, CO

09246200 15 Elkhead Creek 

subwatershed

1995–2003 83 20 <0.010 0.923 0.132 (85th) 0.05 (USEPA recommended)

43 ELKHEAD CREEK NEAR CRAIG, CO 09246500 15 Elkhead Creek 

subwatershed

21975–78 6 1 <0.01 0.17 0.11 (85th) 0.1 (USEPA recommended)
Water-Quality Assessment 31

Table 10. Stream water-quality sites with data in exceedance of Colorado Department of Public Health and Environment in-stream water-quality standards for selected physical properties and water-quality constituents and U.S. Environmental Protection Agency recommended concentrations for total phosphorus, Upper Yampa River watershed, Colorado, 1975 through 2009.—Continued[No., number; Min., minimum; Max., maximum; WS, water supply; SMCL, secondary maximum contaminant level; USEPA, U.S. Environmental Protection Agency; <, less than. Subwatershed definitions: Yampa River subwatershed 1, Yampa River and tributaries upstream from Chuck Lewis State Wildlife Area; Yampa River subwatershed 2, Yampa River and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence; Elk River subwatershed, Elk River and tributaries; Yampa River subwatershed 3, Yampa River and tributaries from Elk River confluence to Town of Hayden; Yampa River subwatershed 4, Yampa River and tributaries from Town of Hayden to Elkhead Creek confluence; Elkhead Creek subwatershed, Elkhead Creek and tributaries. Water-quality standards are from Colorado Department of Public Health and Environment (2009a, 2010); standards are for protection of aquatic life, unless otherwise stated. Recommended concentrations for total phosphorus are from U.S. Environmental Protection Agency (2000). Nonattainment of a standard is based on the 15th, 50th, or 85th percentile value shown in the table. See appendix 3 for additional site information. Descriptions of stream segments are in Colorado Department of Public Health and Environment (2010)]

Site no. 

(see

figures 8, 

12)

Site name in

Upper Yampa River

watershed water-quality database

Site identifier Stream segment Subwatershed

Period of 

water-quality 

record

(calendar 

year)

No. of

samples

No. of

censored

values1

Min.

value

Max.

value

Percentile

value

(percentile)

In-stream water-quality

standard or

recommended value

Total phosphorus, unfiltered (milligrams per liter)5—Continued

63 LITTLE MORRISON CK @ RD 18A 12896 3 Yampa River 

subwatershed 1

22001–07 7 0 0.06 0.13 0.12 (85th) 0.05 (USEPA recommended)

65 LITTLE MORRISON CREEK NEAR 

STAGECOACH, CO.

401634106502200 3 Yampa River 

subwatershed 1

1975–76 4 0 0.12 0.51 0.36 (85th) 0.05 (USEPA recommended)

66 LITTLE WHITE SNAKE CK @ HWY 131 12897 4 Yampa River 

subwatershed 1

2001, 

2006–07

4 0 0.09 0.56 0.40 (85th) 0.1 (USEPA recommended)

115 TROUT CK NR. MOUTH 12876 13f Yampa River 

subwatershed 3

21996–07 22 0 0.02 0.40 0.13 (85th) 0.1 (USEPA recommended)

135 YAMPA R, BL KOA CAMPGROUNDS 

NR STEAMBOAT SPGS, CO.

403017106525800 2c Yampa River 

subwatershed 2

1975–76 4 0 0.11 0.18 0.16 (85th) 0.1 (USEPA recommended)

138 YAMPA R. BLW STAGECOACH RES. 12808 2a Yampa River 

subwatershed 1

1996–99 14 0 0.03 0.13 0.12 (85th) 0.1 (USEPA recommended)

139 YAMPA R. D/S STAGECOACH 

RES. DAM

12808P 2a Yampa River 

subwatershed 1

22000–07 21 0 0.04 0.15 0.11 (85th) 0.1 (USEPA recommended)

140 YAMPA R. N. OF HAYDEN 

@ CALIFORNIA PARK RD

12802 2c Yampa River 

subwatershed 3

21996–99 13 0 0.03 0.26 0.12 (85th) 0.1 (USEPA recommended)

145 YAMPA RIVER ABOVE ELK RIVER 

NEAR MILNER, CO.

402932106564900 2c Yampa River 

subwatershed 2

1975–76 9 0 0.03 0.17 0.16 (85th) 0.1 (USEPA recommended)

147 YAMPA RIVER ABOVE STAGECOACH 

RESERVOIR, CO

09237450 2a Yampa River 

subwatershed 1

1988–92 24 0 0.02 0.20 0.11 (85th) 0.05 (USEPA recommended)

147 YAMPA R. U/S STAGECOACH RES 

@ CR16

12809 2a Yampa River 

subwatershed 1

21999–07 22 1 <0.01 0.10 0.08 (85th) 0.05 (USEPA recommended)

149 YAMPA RIVER AT ELK RIVER 

JUNCTION NR MILNER, CO.

402902106580000 2c Yampa River 

subwatershed 2

1975–76 4 0 0.09 0.15 0.15 (85th) 0.1 (USEPA recommended)

154 YAMPA RIVER BELOW DIVERSION, 

NEAR HAYDEN, CO.

09244410 2c Yampa River 

subwatershed 3

1975–82 81 0 0.01 0.24 0.12 (85th) 0.1 (USEPA recommended)

158 YAMPA RIVER BELOW STAGECOACH 

RESERVOIR, CO

09237500 2a Yampa River 

subwatershed 1

1988–92 24 0 0.03 0.30 0.18 (85th) 0.1 (USEPA recommended)

163 YAMPA RIVER BELOW STEAMBOAT 

II SEWAGE PLANT, CO.

403002106545500 2c Yampa River 

subwatershed 2

1975–76 4 0 0.09 0.24 0.20 (85th) 0.1 (USEPA recommended)
32 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009 Table 10. Stream water-quality sites with data in exceedance of Colorado Department of Public Health and Environment in-stream water-quality standards for selected physical properties and water-quality constituents and U.S. Environmental Protection Agency recommended concentrations for total phosphorus, Upper Yampa River watershed, Colorado, 1975 through 2009.—Continued [No., number; Min., minimum; Max., maximum; WS, water supply; SMCL, secondary maximum contaminant level; USEPA, U.S. Environmental Protection Agency; <, less than. Subwatershed definitions: Yampa River subwatershed 1, Yampa River and tributaries upstream from Chuck Lewis State Wildlife Area; Yampa River subwatershed 2, Yampa River and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence; Elk River subwatershed, Elk River and tributaries; Yampa River subwatershed 3, Yampa River and tributaries from Elk River confluence to Town of Hayden; Yampa River subwatershed 4, Yampa River and tributaries from Town of Hayden to Elkhead Creek confluence; Elkhead Creek subwatershed, Elkhead Creek and tributaries. Water-quality standards are from Colorado Department of Public Health and Environment (2009a, 2010); standards are for protection of aquatic life, unless otherwise stated. Recommended concentrations for total phosphorus are from U.S. Environmental Protection Agency (2000). Nonattainment of a standard is based on the 15th, 50th, or 85th percentile value shown in the table. See appendix 3 for additional site information. Descriptions of stream segments are in Colorado Department of Public Health and Environment (2010)] Site no. (see figures 8, 12) Site name in Upper Yampa River watershed water-quality database Site identifier Stream segment Subwatershed Period of water-quality record (calendar year) No. of samples No. of censored values1 Min. value Max. value Percentile value (percentile) In-stream water-quality standard or recommended value Copper, dissolved (micrograms per liter) 45 ENGLISH CREEK ABOVE MOUTH, NEAR CLARK, CO 404727106453700 20a Elk River subwatershed

21999–2003 7 4 60.566 3.21 2.24 (85th) 2.02 (acute)/1.61 (chronic)

49 FISH CR AT UPPER STA NR STEAMBOAT SPRINGS, CO 09238900 3 Yampa River subwatershed 2 1984–85 3 1 <1 4 4 (85th) 1.72 (acute)/1.39 (chronic)101 SAGE CREEK NEAR HAYDEN, CO. 402918107094400 13e Yampa River 

subwatershed 3

1975–76 3 1 <2 550 400 (85th) 140 (acute)/75 (chronic)

123 WALTON CREEK NEAR STEAMBOAT 

SPRINGS, CO.

09238500 3 Yampa River 

subwatershed 2

1984–85 3 1 <1 7 6 (85th) 2.26 (acute)/1.78 (chronic)

Iron, dissolved (micrograms per liter)

63 LITTLE MORRISON CK @ RD 18A 12896 3 Yampa River 

subwatershed 1

22001–07 7 0 130 570 318 (85th) 300 WS (chronic, SMCL)

166 Yampa River Library CDOWRW-12 2c Yampa River 

subwatershed 2

1991–92 4 0 193 1,001 962 (85th) 300 WS (chronic, SMCL)

170 Yampa River Stagecoach Res CDOWRW-8 2a Yampa River 

subwatershed 1

1990–92, 

2004

16 0 31 667 651 (85th) 300 WS (chronic, SMCL)

Iron, total recoverable (micrograms per liter)

16 CHIMNEY CREEK AT TRAPPER, CO. 400612106524800 5 Yampa River 

subwatershed 1

1975–76 4 0 740 1,400 1,150 (50th) 1,000 (chronic)

17 COW CR. NR. STEAMBOAT 

SPRINGS,CO.

402836106550100 3 Yampa River 

subwatershed 2

1982 4 0 1,500 3,700 2,650 (50th) 1,000 (chronic)

51 FISH CREEK AT MOUTH NEAR 

MILNER, CO.

402530106585700 13b Yampa River 

subwatershed 3

1975–76, 

1982

10 0 370 37,000 6,350 (50th) 1,000 (chronic)

117 TROUT CREEK ABOVE MILNER, CO. 402720106591200 13f Yampa River 

subwatershed 3

1982 4 0 6,000 24,000 9,350 (50th) 1,000 (chronic)

164 Yampa River East Br CDOWRW-13 2c Yampa River 

subwatershed 3

1998 7 0 11 9,636 2,728 (50th) 1,000 (chronic)
Water-Quality Assessment 33

Table 10. Stream water-quality sites with data in exceedance of Colorado Department of Public Health and Environment in-stream water-quality standards for selected physical properties and water-quality constituents and U.S. Environmental Protection Agency recommended concentrations for total phosphorus, Upper Yampa River watershed, Colorado, 1975 through 2009.—Continued[No., number; Min., minimum; Max., maximum; WS, water supply; SMCL, secondary maximum contaminant level; USEPA, U.S. Environmental Protection Agency; <, less than. Subwatershed definitions: Yampa River subwatershed 1, Yampa River and tributaries upstream from Chuck Lewis State Wildlife Area; Yampa River subwatershed 2, Yampa River and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence; Elk River subwatershed, Elk River and tributaries; Yampa River subwatershed 3, Yampa River and tributaries from Elk River confluence to Town of Hayden; Yampa River subwatershed 4, Yampa River and tributaries from Town of Hayden to Elkhead Creek confluence; Elkhead Creek subwatershed, Elkhead Creek and tributaries. Water-quality standards are from Colorado Department of Public Health and Environment (2009a, 2010); standards are for protection of aquatic life, unless otherwise stated. Recommended concentrations for total phosphorus are from U.S. Environmental Protection Agency (2000). Nonattainment of a standard is based on the 15th, 50th, or 85th percentile value shown in the table. See appendix 3 for additional site information. Descriptions of stream segments are in Colorado Department of Public Health and Environment (2010)]

Site no. 

(see

figures 8, 

12)

Site name in

Upper Yampa River

watershed water-quality database

Site identifier Stream segment Subwatershed

Period of 

water-quality 

record

(calendar 

year)

No. of

samples

No. of

censored

values1

Min.

value

Max.

value

Percentile

value

(percentile)

In-stream water-quality

standard or

recommended value

Manganese, dissolved (micrograms per liter)

63 LITTLE MORRISON CK @ RD 18A 12896 3 Yampa River 

subwatershed 1

22001–07 7 0 29 83 75 (85th) 50 WS (chronic, SMCL)

83 OAK CK D/S TOWN OF OAK CREEK 

@ CR 27

12892 6 Yampa River 

subwatershed 1

1999–2007 14 0 14 100 52 (85th) 50 WS (chronic, SMCL)

91 Oak Creek Decker Pk CDOWRW-80 6 Yampa River 

subwatershed 1

1991–92 13 0 31 116 81 (85th) 50 WS (chronic, SMCL)

115 TROUT CK NR. MOUTH 12876 13f Yampa River 

subwatershed 3

21996–07 22 0 11 75 68 (85th) 50 WS (chronic, SMCL)

122 WALTON CR. NEAR MOUTH 

@ HWY 40

12894 3 Yampa River 

subwatershed 2

1999, 

2006–07

5 0 16 130 72 (85th) 50 WS (chronic, SMCL)

124 WALT [Walton Creek 10m above 

Hwy 40 bridge]

WALT 3 Yampa River 

subwatershed 2

2007–08 4 0 12 133 84 (85th) 50 WS (chronic, SMCL)

129 YAMPA ABOVE OAK CREEK 

CONFLUENCE

000088 2a Yampa River 

subwatershed 1

1988–93 22 4 616 160 78 (85th) 50 WS (chronic, SMCL)

138 YAMPA R. BLW STAGECOACH RES. 12808 2a Yampa River 

subwatershed 1

1996–99 14 1 <4 220 180 (85th) 50 WS (chronic, SMCL)

139 YAMPA R. D/S STAGECOACH 

RES. DAM

12808P 2a Yampa River 

subwatershed 1

22000–07 21 0 50 210 170 (85th) 50 WS (chronic, SMCL)

140 YAMPA R. N. OF HAYDEN 

@ CALIFORNIA PARK RD

12802 2c Yampa River 

subwatershed 3

21996–99 13 1 <4 68 58 (85th) 50 WS (chronic, SMCL)

143 YAMPA RIVER AB OAK CREEK NR 

STEAMBOAT SPGS, CO.

402356106500000 2a Yampa River 

subwatershed 1

1975–76 4 1 <10 60 60 (85th) 50 WS (chronic, SMCL)

143 YAMPA R. ABV OAK CREEK 12811 2a Yampa River 

subwatershed 1

1996–2002 30 0 5 120 87 (85th) 50 WS (chronic, SMCL)

153 YAMPA RIVER AT STEAMBOAT 

SPRINGS, CO

09239500 2c Yampa River 

subwatershed 2

21975–2009 68 2 63.5 130 76 (85th) 50 WS (chronic, SMCL)

153 YAMPA R. @ 5TH ST. BRIDGE IN 

STEAMBOAT

12806 2c Yampa River 

subwatershed 2

21996–2007 37 1 <4 120 72 (85th) 50 WS (chronic, SMCL)
34 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009 Table 10. Stream water-quality sites with data in exceedance of Colorado Department of Public Health and Environment in-stream water-quality standards for selected physical properties and water-quality constituents and U.S. Environmental Protection Agency recommended concentrations for total phosphorus, Upper Yampa River watershed, Colorado, 1975 through 2009.—Continued [No., number; Min., minimum; Max., maximum; WS, water supply; SMCL, secondary maximum contaminant level; USEPA, U.S. Environmental Protection Agency; <, less than. Subwatershed definitions: Yampa River subwatershed 1, Yampa River and tributaries upstream from Chuck Lewis State Wildlife Area; Yampa River subwatershed 2, Yampa River and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence; Elk River subwatershed, Elk River and tributaries; Yampa River subwatershed 3, Yampa River and tributaries from Elk River confluence to Town of Hayden; Yampa River subwatershed 4, Yampa River and tributaries from Town of Hayden to Elkhead Creek confluence; Elkhead Creek subwatershed, Elkhead Creek and tributaries. Water-quality standards are from Colorado Department of Public Health and Environment (2009a, 2010); standards are for protection of aquatic life, unless otherwise stated. Recommended concentrations for total phosphorus are from U.S. Environmental Protection Agency (2000). Nonattainment of a standard is based on the 15th, 50th, or 85th percentile value shown in the table. See appendix 3 for additional site information. Descriptions of stream segments are in Colorado Department of Public Health and Environment (2010)] Site no. (see figures 8, 12) Site name in Upper Yampa River watershed water-quality database Site identifier Stream segment Subwatershed Period of water-quality record (calendar year) No. of samples No. of censored values1 Min. value Max. value Percentile value (percentile) In-stream water-quality standard or recommended value Manganese, dissolved (micrograms per liter)—Continued 158 Yampa River Below Stagecoach CDOWRW-81 2a Yampa River subwatershed 1 2004 5 0 54 216 180 (85th) 50 WS (chronic, SMCL) 166 Yampa River Library CDOWRW-12 2c Yampa River subwatershed 2 1991–92 8 0 13 94 86 (85th) 50 WS (chronic, SMCL) 168 YAMPA RIVER NEAR HAYDEN, CO. 09244400 2c Yampa River subwatershed 3 1979 3 0 20 60 54 (85th) 50 WS (chronic, SMCL) 171 Yampa River SWA Br CDOWRW-10 2a Yampa River subwatershed 1 1991–92 15 0 11 144 83 (85th) 50 WS (chronic, SMCL) Selenium, dissolved (micrograms per liter) 22 DRY CK @ HAYDEN 12852 13d Yampa River subwatershed 4

22001–05 7 2 <1 120 52 (85th) 18.4 (acute)/4.6 (chronic)

59 GRASSY CREEK NEAR MOUNT 

HARRIS, CO.

09244300 13e Yampa River 

subwatershed 3

1975–76, 

1982

5 3 <1 34 25 (85th) 18.4 (acute)/4.6 (chronic)

59 GRASSY CK @ RD. 27A 12853 13e Yampa River 

subwatershed 3

2001, 

2004–07

7 1 <1 42 26 (85th) 18.4 (acute)/4.6 (chronic)

98 SAGE CK @ RD. 27 12851 13e Yampa River 

subwatershed 3

2001, 

2004–07

7 1 <1 290 188 (85th) 18.4 (acute)/4.6 (chronic)

101 SAGE CREEK NEAR HAYDEN, CO. 402918107094400 13e Yampa River

subwatershed 3

1975–76 5 1 <1 52 24 (85th) 18.4 (acute)/4.6 (chronic)

112 STOKES GULCH NEAR HAYDEN, CO. 09244470 13d Yampa River

subwatershed 4

1978–81 5 0 24 300 166 (85th) 18.4 (acute)/4.6 (chronic)

158 Yampa River Below Stagecoach CDOWRW-81 2a Yampa River

subwatershed 1

2004 3 0 2.2 7.9 6.5 (85th) 18.4 (acute)/4.6 (chronic)

1Censored values can be expressed as values less than the laboratory reporting level.2Sample collection did not occur during every year in the period of record.3Continuous monitoring (15-minute intervals) of water temperature only occurred at Yampa River at Steamboat Springs (site 153). Temperature measurements were collected on most sample days from 

July 26, 2002, through April 13, 2005. See figure 9 and table 11 for temperature standards and the number of exceedances of the standards.

4For stream segments with dissolved solids data, the standard has being applied to stream segments that have standards for unfiltered sulfate and chloride.5For stream segments with unfiltered total phosphorus data, the recommendation has been applied to stream segments that have a standard for unfiltered nitrate.6Minimum censored value is greater than minimum detected value.
Water-Quality Assessment 35

Figure 9. Daily Maximum Temperature (DM), Maximum Weekly Average Temperature (MWAT), and daily average streamflow 

with exceedances of Colorado Department of Public Health and Environment (CDPHE) in-stream water-quality standards for water 

temperature for (A) June–September DM, (B) June–September MWAT, (C) October–May DM, and (D) October–May MWAT for Yampa 

River at Steamboat Springs (site 153), Upper Yampa River watershed, Colorado, 2002 though 2005. Daily maximum water temperature, in degrees Celsius 

Date

0

5

10

15

20

25

30

1,000

2,000

3,000

4,000

5,000

Colorado Department of Public Health and 

 Environment DM water-quality standard, 

 June−September (21.2° Celsius)

Daily average streamflow

Maximum 2-hour average water temperature 

 for a 24-hour period (DM), June–September 

July 26

July 12

July 10

Sept. 4

Sept. 4

Aug. 17

Dates near standard line indicate first and last days with 

water temperature greater than the standard

1/1/2002

7/1/2002

1/1/2004

1/1/20057/1/2005

1/1/2006

0

5

10

15

20

25

0

1,000

2,000

3,000

4,000

5,000

Date

Aug. 1

Sept. 10

Sept. 9

Aug. 24

July 3

July 9

Colorado Department of Public Health 

 and Environment MWAT water-quality 

 standard, June−September (17.0° Celsius)

Daily average streamflow

Maximum 7-day average of daily water 

 temperature (MWAT), June−September

Dates near standard line indicate first and last days 

with water temperature greater than the standard

A

B

EXPLANATION

EXPLANATION

Maximum weekly average temperature, 

in degrees Celsius

Daily average streamflow, 

in cubic feet per second

Daily average streamflow, 

in cubic feet per second

1/1/2003

7/1/2003

7/1/2004

1/1/20027/1/20021/1/20041/1/20057/1/20051/1/20061/1/20037/1/20037/1/2004

0
36 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Figure 9. Daily Maximum Temperature (DM), Maximum Weekly Average Temperature (MWAT), and daily average streamflow 

with exceedances of Colorado Department of Public Health and Environment (CDPHE) in-stream water-quality standards for water 

temperature for (A) June–September DM, (B) June–September MWAT, (C) October–May DM, and (D) October–May MWAT for Yampa 

River at Steamboat Springs (site 153), Upper Yampa River watershed, Colorado, 2002 though 2005.—Continued

0

5

10

15

20

25

30

0

1,000

2,000

3,000

4,000

5,000

Oct. 1*

Oct. 10*

Oct. 23

Oct. 1

April 12–13

April 26–May 4*

C

0

5

10

15

20

25

0

1,000

2,000

3,000

4,000

5,000

Date

Oct. 14

Oct. 1

May

31*

Oct. 30

Oct. 1

April

29*

Oct. 18

Oct. 1

D

Maximum weekly average temperature, 

in degrees Celsius

Daily average streamflow, 

in cubic feet per second

Daily average streamflow, 

in cubic feet per second

Daily maximum water temperature,

in degrees Celsius 

Date

1/1/20027/1/20021/1/20041/1/20057/1/20051/1/20061/1/20037/1/20037/1/2004

1/1/20027/1/20021/1/20041/1/20057/1/20051/1/20061/1/20037/1/20037/1/2004

Colorado Department of Public Health and 

 Environment DM water-quality standard, 

 October−May (21.2° Celsius)

Daily average streamflow

Maximum 2-hour average water temperature 

 for a 24-hour period (DM), October–May

Dates near standard line indicate first and last days with 

water temperature greater than the standard. *Exceedance

did not occur every day between the dates shown.

EXPLANATION

Colorado Department of Public Health 

 and Environment water-quality standard, 

 October−May (9.0° Celsius)

Daily average streamflow

Maximum 7-day average of daily water 

 temperature (MWAT), October–May

Dates near standard line indicate first and last days with 

water temperature greater than the standard. *Exceedance

did not occur every day between the dates shown.

EXPLANATION

May 14
Water-Quality Assessment 37

Dissolved oxygen in the UYRW was measured for 2,797 

samples from 1975 through 2009 and ranged from 1.2 to 

17.8 mg/L with a median of 9.8 mg/L (table 8). Median dissolved oxygen concentrations were between 9.8 and 10.1 mg/L 

for each subwatershed, except Yampa River subwatershed 4. 

In this subwatershed, the median dissolved oxygen concentration was lower (9.2 mg/L) and the median water temperature was higher than those in any other subwatershed in the 

watershed. The lowest dissolved oxygen concentrations (less 

than 5.0 mg/L) in the watershed generally occurred during 

late June through August when streamflow was lower and 

water temperatures were higher than at other times of the year. 

The CDPHE standard for dissolved oxygen was met at about 

99 percent of sites with data available for comparison to the 

standard, indicating adequate conditions for aquatic life. Two 

sites in this study, Little White Snake Creek (site 66, stream 

not named on fig. 3) and Martin Creek (site 70, stream not 

named on fig. 3), had concentrations that were not in attainment of the CDPHE standard (table 10). Little White Snake 

Creek is on the CDPHE 2012 monitoring and evaluation list 

for dissolved oxygen (Colorado Department of Public Health 

and Environment, 2012). Data for this site were available for 

2001, 2006, and 2007. Determination of nonattainment of the 

standard for Martin Creek was based on data collected from 

1986 through 1988.

Hardness generally is measured by the presence of the 

cations calcium and magnesium in water and is reported in 

terms of an equivalent concentration of calcium carbonate. 

Hardness can affect the anthropogenic uses of water and the 

toxicity of metals to aquatic life. Metal toxicity can increase as 

hardness decreases (Santore and others, 2001). Waters draining igneous rocks generally contain little hardness because 

of the absence of calcium and magnesium cations in the 

water. Waters draining sandstones and shales, as well as other 

sedimentary rocks that contain carbonate, have harder water. 

Additionally, additives from municipal water treatment, agricultural fertilizers, and applications of chemicals for winter 

road maintenance can increase hardness in water.

In the UYRW, hardness was measured for 2,434 samples 

from 1975 through 2009 and ranged from 4 to 4,000 mg/L 

with a median of 162 mg/L (table 8). Hardness generally 

was lowest (softer water) in the Elk River subwatershed and 

Yampa River subwatershed 2, where igneous and metamorphic 

rocks underlie much of the land surface, and highest (harder 

water) in Yampa River subwatersheds 3 and 4 (table 8), where 

sedimentary rocks predominate. Hardness was generally 

higher when streamflow was primarily base flow from groundwater than during snowmelt runoff.

Acid neutralizing capacity (determined on an unfiltered water sample) and alkalinity (determined on a filtered 

sample) measure the ability of a water sample to neutralize 

inputs of acid from precipitation, wastewater, or mine drainage (Rounds, 2006). Bicarbonate and carbonate are the main 

buffering materials. Water with low ANC is susceptible to pH 

change with the addition of acidic water; water with high ANC 

is buffered and resists pH change. Waters with high ANC 

occur in areas with sedimentary rocks and carbonate-rich 

materials.

In the UYRW, ANC was measured for 2,244 samples 

collected at 134 sites, most commonly for Yampa River 

subwatersheds 1 and 3. Values for ANC ranged from 2 to 

660 mg/L with a median of 136 mg/L (table 8). Lower values 

typically occurred during snowmelt runoff than others times 

of the year. As with hardness, the Elk River subwatershed and 

Yampa River subwatershed 2 had the lowest median ANC, 

and the Yampa River subwatersheds 3 and 4 had the highest median ANC because of the underlying geology (figs. 5, 

6C). In the Rocky Mountains, contaminants in precipitation, 

including sulfuric and nitric acids, pose a threat to alpine and 

subalpine ecosystems, such as Mount Zirkel and Flat Tops 

Wilderness areas in the UYRW (fig. 1), because water, local 

soil types, and bedrock have little capacity to buffer acidic 

inputs (Turk and Spahr, 1991). As the accumulated snowpack 

melts, a pulse of strong acids can be released into the aquatic 

system (Campbell and Turk, 1989).

Table 11. Number of sample days with water temperature at Yampa River at Steamboat Springs (site 153) not meeting Colorado 

Department of Public Health and Environment in-stream water-quality standards, July 26, 2002, through April 13, 2005.

[°C, degrees Celsius; DM, Daily Maximum Temperature; MWAT, Maximum Weekly Average Temperature. Water-quality standards are from Colorado Department 

of Public Health and Environment (2009a, 2010). Continuous (15-minute interval) temperature data were available for July 26, 2002 through April 13, 2005. See 

figure 3 for location of site]

In-stream 

water-quality standard

(°C)

Number of

sample days

Number of sample days

not meeting standard

Percentage of sample days

not meeting standard

(percent)

21.2 (cold, acute DM, June–September) 311 113 36

17.0 (cold, chronic MWAT, June–September) 305 151 50

13.0 (cold, acute DM, October–May) 578 32 5.5

9.0 (cold, chronic MWAT, October–May) 608 88 14
38 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Dissolved Solids and Major Ions

In most natural waters, dissolved solids are composed of 

commonly occurring major ions such as calcium, magnesium, 

sodium, potassium, bicarbonate, carbonate, sulfate, chloride, 

fluoride, and silica. For this study, dissolved solids are materials dissolved in water that pass through a 0.45-micron filter. 

Most dissolved ions originate when water reacts with mineral 

assemblages in rocks and soils near the land surface (Hem, 

1992). The amount and composition of dissolved solids can be 

used to identify sources of and changes in water chemistry at 

different times of the year.

In the UYRW, dissolved solids were measured in 

1,743 samples collected from 1975 through 2009 (tables 6, 

7). Concentrations ranged from 6.5 to 9,280 mg/L, and the 

median was 216 mg/L (table 12). Among the subwatersheds, 

the median concentration was highest for Yampa River 

subwatershed 4, which likely resulted from the weathering 

of sedimentary rocks that underlie the subwatershed, and the 

lowest for the Elk River subwatershed, an area that drains 

relatively non-reactive igneous and metamorphic rocks. 

Because values of dissolved solids and specific conductance 

in water are proportional, the spatial distribution of dissolved solids concentrations in the UYRW is similar to that 

of specific conductance (fig. 6A). Tributaries to the Yampa 

River in subwatershed 2 and the Elk River, the major tributary 

to the Yampa River in Yampa River subwatershed 3, carried fewer dissolved solids than tributaries in Yampa River 

subwatersheds 1 and 4. The 85th percentile concentration of 

dissolved solids for one site, Trout Creek near the mouth (site 

115), in Yampa River subwatershed 3 was greater than the 

nonenforceable SMCL of 500 mg/L (table 10). High dissolved 

solids concentrations can limit the use of water for municipal 

and agricultural uses and can affect aquatic life.

Major ions in water are a product of the interaction of 

groundwater and aquifer materials, lithology, soils, and human 

activity. In this section, major ions are dissolved concentrations unless stated otherwise. A total of 1,921 samples 

analyzed for major ions were collected in the UYRW from 

1975 through 2009 at 130 stream sites (tables 6, 7). The most 

sites sampled and the most samples collected were in Yampa 

River subwatershed 3; the fewest sites and fewest samples 

were recorded for the Elkhead Creek subwatershed and Yampa 

River subwatershed 4, respectively (tables 6, 7).

A total of 172 samples had sufficient data for calcium, 

magnesium, potassium, sodium, bicarbonate, chloride, 

fluoride, and sulfate to determine the ionic composition of 

water. For most subwatersheds, the primary cations in solution 

were calcium or calcium plus magnesium, and the primary 

anions were bicarbonate or bicarbonate plus sulfate (fig. 10). 

The most diverse water type was for streams in Yampa River 

subwatershed 4. Hubberson and Watering Trough Gulches (not 

named in figure 3) near Hayden (sites 61 and 125, respectively), which are underlain by the Williams Fork Formation, 

had a calcium plus magnesium and bicarbonate plus sulfate 

water type. Stokes Gulch (not named in figure 3) near Hayden 

(site 112), underlain by the Lewis Shale, had a sodium plus 

potassium plus magnesium and sulfate water type. In the 

Williams Fork aquifer of the Mesaverde Group, the dissolution of calcite and dolomite from limey shales, limestones, and 

dolomitic limestones is a source of calcium and magnesium 

(Robson and Stewart, 1990). In areas with marine shales, such 

as the Lewis Shale, the exchange of calcium and magnesium 

ions in solution with sodium ions on the clay minerals in 

sodium-rich marine shales is the principal source of sodium in 

the groundwater (Robson and Stewart, 1990).

Median dissolved sulfate concentrations were highest 

in Yampa River subwatersheds 3 and 4 (fig. 6D, table 12) 

because of the prevalence of sedimentary rocks in the subwatersheds. Attainment of the CDPHE water-supply standard 

for unfiltered sulfate was not met at about 4 percent (2 of 52) 

of the sites sampled. One site not in attainment was on Little 

White Snake Creek (site 66) in Yampa River subwatershed 

1, and the other site was on Trout Creek (site 115) in Yampa 

River subwatershed 3 (fig. 8, table 10). Both sites have drainage basins that overlie sedimentary rocks. The CDPHE has 

not established a sulfate standard for many stream segments 

in Yampa River subwatershed 3 and a few segments in the 

Yampa River subwatersheds 1 and 4 because of naturally high 

concentrations of sulfate.

All unfiltered chloride concentrations in the UYRW 

were 76 mg/L or less. The concentrations were well below the 

CDPHE water-quality standard of 250 mg/L (table 12).

Concentrations of major ions and dissolved solids typically were lower during snowmelt runoff in May and June than 

at other times of the year, as illustrated by monthly dissolved 

sulfate concentrations for Yampa River at Milner (site 151) 

(fig. 7B). This seasonal variation in concentrations is primarily 

because of the water source and increased volume of streamflow. Snowmelt typically is lower in dissolved materials than 

groundwater inflow to streams because snowmelt runoff has 

little soil and (or) rock interaction compared to groundwater. 

Because of the strong influence of snowmelt runoff on water 

quality, it is difficult to identify other natural and human factors that may affect major ion and dissolved solids concentrations. Typically, major ion and dissolved solids concentrations 

increase steadily through the summer and fall as inflow from 

groundwater becomes the major source of water to a stream.

Only one site, Yampa River at Steamboat Springs (site 

153), had sufficient dissolved solids and major ion data for 

temporal trend analysis. A statistically significant (p-value 

0.03) downward trend in dissolved solids concentrations was 

identified for data collected from 1997 through 2008 (table 9).

The rate of changed was small, about 3 percent per year (magnitude about 3.9 mg/L per year). The median dissolved solids 

concentration at the site was 153 mg/L. A similar downward 

trend was identified for specific conductance at the site. No 

statistically significant (p-values 0.06–0.77) trends were 

identified for calcium, magnesium, sodium, potassium, sulfate, 

chloride, and silica concentrations in stream water at Yampa 

River at Steamboat Springs (site 153).
Water-Quality Assessment 39

Table 12. Summary statistics for dissolved solids and selected major ion water-quality data and Colorado Department of Public Health 

and Environment in-stream water-quality standards for stream sampling sites in the Upper Yampa River watershed and subwatersheds, 

Colorado, 1975 through 2009.—Continued

[No., number; WS, water supply; SMCL, secondary maximum contaminant level; --, no water-quality standard; <, less than. All constituent values are reported 

in milligrams per liter. Number of significant figures for individual constituents may vary because data are from different sources and analytical periods. Waterquality standards are from Colorado Department of Public Health and Environment (2009a, 2010). See table 10 for sites in the Upper Yampa River watershed 

and subwatersheds with data for dissolved solids and major ions not in attainment of in-stream water-quality standards. Descriptions of stream segments are in 

Colorado Department of Public Health and Environment (2010)]

Constituent No. of

sites

No. of

samples

No. of

censored

values1

Minimum

value2

Median

value

Maximum

value

In-stream

water-quality standard

No. of sites with

data not in attainment

of standard

Upper Yampa River watershed

Dissolved solids 110 1,743 1 6.5 216 9,280 3,4500 WS (SMCL) or none 1

Calcium, dissolved 75 1,064 0 1.4 39.5 480 -- --

Magnesium, dissolved 75 1,066 0 0.2 15.1 810 -- --

Sodium, dissolved 65 1,022 0 0.6 18 1,400 -- --

Potassium, dissolved 65 1,019 0 0.2 2.2 19 -- --

Bicarbonate, dissolved 28 184 0 14 147 550 -- --

Sulfate, dissolved 69 1,020 16 0.65 64.6 6,200 -- --

Sulfate, unfiltered 52 833 67 <3 36 4,300 4250 WS (SMCL) or none 2

Chloride, dissolved 66 1,016 18 <0.1 3.9 240 -- --

Chloride, unfiltered 16 101 5 <0.002 6 76 4250 WS (SMCL) or none 0

Fluoride, dissolved 68 992 172 <0.001 0.2 1.0 -- --

Silica, dissolved 66 1,012 0 0.009 8.8 28 -- --

Yampa River and tributaries upstream from Chuck Lewis State Wildlife Area

(Yampa River subwatershed 1; stream segments 2a, 2c, 3, 4, 5, 6, 7)

Dissolved solids 28 429 0 43 260 1,130 3,4500 WS (SMCL) or none 0

Calcium, dissolved 8 84 0 21 53.7 130 -- --

Magnesium, dissolved 8 84 0 7.1 19.7 36 -- --

Sodium, dissolved 6 74 0 3.5 12 32 -- --

Potassium, dissolved 6 74 0 0.4 2.2 4.5 -- --

Bicarbonate, dissolved 3 7 0 160 211 257 -- --

Sulfate, dissolved 6 73 6 <5 55 250 -- --

Sulfate, unfiltered 22 389 3 <3 45 340 4250 WS (SMCL) or none 1

Chloride, dissolved 6 74 0 0.4 2.4 14 -- --

Chloride, unfiltered 10 46 2 <1 4 76 4250 WS (SMCL) or none 0

Fluoride, dissolved 6 74 5 <0.001 0.2 0.6 -- --

Silica, dissolved 6 74 0 6.9 19 28 -- --

Yampa River and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence

(Yampa River subwatershed 2; stream segments 2c, 3, 20a)

Dissolved solids 13 166 1 6.5 89.4 471 3500 WS (SMCL) 0

Calcium, dissolved 19 157 0 1.4 12.1 100 -- --

Magnesium, dissolved 19 157 0 0.2 2.7 18 -- --

Sodium, dissolved 11 125 0 0.7 2.6 30 -- --

Potassium, dissolved 11 125 0 0.2 0.9 4.9 -- --

Bicarbonate, dissolved 3 26 0 15 111 157 -- --

Sulfate, dissolved 12 125 4 0.65 5.0 160 -- --

Sulfate, unfiltered 6 61 17 <3 14 54 250 WS (SMCL) 0

Chloride, dissolved 12 125 3 <0.1 1.1 12 -- --

Fluoride, dissolved 12 123 61 0.03 0.08 0.9 -- --

Silica, dissolved 12 120 0 2.4 8.9 18 -- --

Elk River and tributaries

(Elk River subwatershed; stream segments 8, 20a)

Dissolved solids 17 200 0 12.7 29.6 180 3500 WS (SMCL) 0

Calcium, dissolved 10 130 0 1.9 5.9 29 -- --

Magnesium, dissolved 10 130 0 0.3 1.2 10.6 -- --

Sodium, dissolved 10 130 0 0.6 1.6 9.2 -- --

Potassium, dissolved 10 130 0 0.2 0.8 4.7 -- --

Bicarbonate, dissolved 3 10 0 14 38.5 78 -- --

Sulfate, dissolved 10 128 0 0.73 3.2 53 -- --

Sulfate, unfiltered 7 90 38 <3 7 50 250 WS (SMCL) 0

Chloride, dissolved 10 128 15 <0.1 0.3 4.6 -- --

Chloride, unfiltered 1 7 1 2 4 4 250 WS (SMCL) 0

Fluoride, dissolved 9 101 60 <0.1 <0.1 0.4 -- --

Silica, dissolved 10 129 0 1.7 7.0 14.7 -- --
40 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Table 12. Summary statistics for dissolved solids and selected major ion water-quality data and Colorado Department of Public Health 

and Environment in-stream water-quality standards for stream sampling sites in the Upper Yampa River watershed and subwatersheds, 

Colorado, 1975 through 2009.—Continued

[No., number; WS, water supply; SMCL, secondary maximum contaminant level; --, no water-quality standard; <, less than. All constituent values are reported 

in milligrams per liter. Number of significant figures for individual constituents may vary because data are from different sources and analytical periods. Waterquality standards are from Colorado Department of Public Health and Environment (2009a, 2010). See table 10 for sites in the Upper Yampa River watershed 

and subwatersheds with data for dissolved solids and major ions not in attainment of in-stream water-quality standards. Descriptions of stream segments are in 

Colorado Department of Public Health and Environment (2010)]

Constituent No. of

sites

No. of

samples

No. of

censored

values1

Minimum

value2

Median

value

Maximum

value

In-stream

water-quality standard

No. of sites with

data not in attainment

of standard

Yampa River and tributaries from Elk River confluence to Town of Hayden

(Yampa River subwatershed 3; stream segments 2c, 11, 12, 13a, 13b, 13c, 13e, 13f, 20a)

Dissolved solids 33 647 0 10 321 5,650 3,4500 WS (SMCL) or none 1

Calcium, dissolved 23 429 0 6.6 78 480 -- --

Magnesium, dissolved 23 431 0 1.5 37 310 -- --

Sodium, dissolved 23 429 0 1.9 32 540 -- --

Potassium, dissolved 23 425 0 0.5 3.4 19 -- --

Bicarbonate, dissolved 11 116 0 21 160 510 -- --

Sulfate, dissolved 26 429 6 1.8 170 2,300 -- --

Sulfate, unfiltered 13 248 9 <3 30 4,300 4250 WS (SMCL) or none 1

Chloride, dissolved 23 424 0 0.3 6.5 59 -- --

Chloride, unfiltered 4 47 2 <0.002 12 53 4250 WS (SMCL) or none 0

Fluoride, dissolved 26 430 10 <0.001 0.2 1.0 -- --

Silica, dissolved 23 423 0 0.2 8 18 -- --

Yampa River and tributaries from Town of Hayden to Elkhead Creek confluence

(Yampa River subwatershed 4; stream segments 2c, 12, 13d)

Dissolved solids 10 101 0 60 709 9,280 3,4500 WS (SMCL) or none 0

Calcium, dissolved 8 78 0 33 110 280 -- --

Magnesium, dissolved 8 78 0 13 72 810 -- --

Sodium, dissolved 8 78 0 11 54 1,400 -- --

Potassium, dissolved 8 79 0 2.1 5 12 -- --

Bicarbonate, dissolved 4 17 0 144 360 550 -- --

Sulfate, dissolved 8 80 0 46 360 6,200 -- --

Sulfate, unfiltered 3 26 0 8 57 3,800 4250 WS (SMCL) or none 0

Chloride, dissolved 8 80 0 3.4 12.5 240 --

Chloride, unfiltered 1 1 0 13 13 13 4

250 WS (SMCL) or none 0

Fluoride, dissolved 9 81 1 <0.001 0.3 0.6 -- --

Silica, dissolved 8 80 0 0.1 8.1 19 -- --

Elkhead Creek and tributaries

(Elkhead Creek subwatershed; stream segments 14, 15, 20b)

Dissolved solids 9 200 0 68 202 635 3500 WS (SMCL) 0

Calcium, dissolved 7 186 0 13 31 71 -- --

Magnesium, dissolved 7 186 0 3.8 12.3 39.3 -- --

Sodium, dissolved 7 186 0 3.6 19.0 77.5 -- --

Potassium, dissolved 7 186 0 0.76 1.6 4.5 -- --

Bicarbonate, dissolved 4 8 0 72 167 232 -- --

Sulfate, dissolved 7 185 0 11.3 52.2 347 -- --

Sulfate, unfiltered 1 19 0 17 82 130 250 WS (SMCL) 0

Chloride, dissolved 7 185 0 0.3 3.0 12 250 WS (SMCL) 0

Fluoride, dissolved 6 183 35 0.081 0.13 0.3 -- --

Silica, dissolved 7 186 0 0.009 9.9 16.1 -- -- 1

Censored values can be expressed as values less than the laboratory reporting level.

2

For some constituents with censored data, the minimum censored value is greater than the minimum detected value that is shown.

3

For stream segments with dissolved solids data, the standard has been applied to stream segments that have standards for unfiltered sulfate and chloride.

4

Water-quality standard varies by stream segment. See Colorado Department of Public Health and Environment (2010).
Water-Quality Assessment 41

Figure 10. Major cation and anion percentages and water type for water-quality samples collected from selected 

stream sites, by subwatershed, Upper Yampa River watershed, Colorado, 1975 through 2009.

Nutrients

Nutrients (nitrite, nitrate, ammonia, phosphorus, and 

orthophosphate) in stream water provide essential food for 

plants and animals. They can occur naturally in water from 

the weathering and erosion of rocks and soils, breakdown of 

organic matter, and atmospheric deposition but also can result 

from human activities. These activities can include application of fertilizers, runoff from agricultural and urban areas, 

soil erosion, effluent from the wastewater-treatment process, 

seepage from septic tanks, detergents, animal waste, and 

combustion of fuels such as coal, petroleum, and wood. Nitrite 

typically is found in low concentrations in streams, often at 

concentrations near laboratory detection levels, because it 

is unstable in aerated water. High levels of nitrite generally 

indicate pollution through disposal of sewage or organic waste 

(Hem, 1992). Nitrate is a more stable species of nitrogen 

in aerated water. It can be found in low concentrations in 

streams and lakes because it is readily consumed by aquatic 

plants but can also occur at high concentrations because of 

natural sources or human activities. Excessive concentrations 

of nitrate in drinking water may cause methemoglobinemia, 

commonly known as blue baby syndrome, in small children 

(Hem, 1992). Ammonia occurs in water as ammonium (NH4+) 

and (or) un-ionized ammonia (NH3). Ammonium is the form 

of ammonia that is the available nutrient; un-ionized ammonia 

is the form that can be toxic to fish in excessive concentrations. Toxicity varies depending on species and is pH and 

Chloride + Fluoride +Sulfate

Calcium + magnesium

100

80

60

40

20

0

100

80

60

40

20

0

Sulfate

Calcium Chloride + Fluoride

Percentage of milliequivalents per liter

Bicarbonate

100

100

80

80

60

60

40

40

20

20

0

0

Sodium + potassium

100

100

80

80

60

60

40

40

20

20

0

0

PERCENT

Magnesium

20

0

40

60

80

100

20

0

40

60

80

100

PERCENT

EXPLANATION

Yampa River subwatershed 4

Yampa River subwatershed 3

Yampa River subwatershed 2

Elkhead Creek subwatershed

Yampa River subwatershed 1

Elk River subwatershed

PERCENT

100 80 60 40 20 0 0 20 40 60 80 100
42 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

temperature dependent (toxicity increases as pH and temperature increase), with pH having a larger effect on toxicity 

that temperature. Phosphorous often adsorbs to the surface 

of sediment and organic particles, which reduces concentrations of phosphorus in streams. The presence of phosphorus in 

surface water can indicate that erosion and sediment transport 

are occurring (Mueller and others, 1995).

An increase in the supply of nutrients, especially nitrates 

and phosphates, to surface water from natural and (or) artificial sources can result in eutrophication. In eutrophic water, 

high concentrations of nutrients can stimulate excessive algal 

growth. As algae die and decompose, dissolved oxygen is 

consumed, and the amount of dissolved oxygen available 

for aquatic life is reduced or depleted. Eutrophication in 

surface water can result in habitat loss, toxic algal blooms, 

reduction in biodiversity, taste and odor issues, pH fluctuations, and clogged municipal water intake pipes (Wetzel, 1983; 

Murphy, 2007a).

In the UYRW, 2,162 samples with nutrient (nitrogen 

and phosphorus) data were collected from 164 stream sites 

(table 6). The spatial and temporal distribution of sample 

collection was similar to that for physical properties and 

major ions. More sites were sampled and more samples were 

collected in Yampa River subwatersheds 1 and 3 than in other 

subwatersheds; the fewest sites sampled and fewest samples 

collected were in the Elkhead Creek subwatershed and Yampa 

River subwatershed 4, respectively (table 6).

Dissolved nitrite was measured for 628 samples collected from 1981 through 2009; concentrations ranged from 

less than 0.001 to 0.39 mg/L as nitrogen (N) with a median of 

0.002 mg/L as N (all nitrite, nitrate, and total ammonia data 

that are discussed are in the nitrogen form, as N) (table 13). 

Concentrations of dissolved nitrite in 85 percent of all 

samples, and in every sample collected from 2002 through 

2009, were 0.01 mg/L or less. Although 9 of 628 individual 

samples had concentrations of unfiltered nitrite greater than 

the CDPHE aquatic-life standard of 0.05 mg/L, attainment 

of the standard was met for all sites. The 85th percentile 

concentration for each site with three or more samples of 

unfiltered nitrite data was less than or equal to 0.02 mg/L. 

Temporal trends testing could not be performed using nitrite 

data because more than 10 percent of the nitrite concentrations 

were censored and did not meet the statistical requirements for 

trends testing.

Dissolved nitrate was measured for 1,096 samples 

collected from 1975 through 2009. Concentrations ranged 

from less than 0.005 to 90 mg/L with a median of 0.07 mg/L 

(table 13). For many sites, more than 50 percent of the data 

were censored. All samples collected after 1988 had dissolved 

nitrate concentrations of 1.5 mg/L or less. Median concentrations were highest in the Yampa River subwatersheds 3 

and 4 (table 13). A total of 37 samples collected in these two 

subwatersheds before 1989 were the only UYRW samples 

with dissolved nitrate concentrations greater than 5 mg/L. The 

85th percentile concentration of unfiltered nitrate data for each 

site in the UYRW with three of more samples was in attainment of the CDPHE MCL for unfiltered nitrate of 10 mg/L 

(appendix 2). Attainment also was met for sites with an the 

agricultural-use standard of 100 mg/L. Statistical requirements 

for trends testing of dissolved and unfiltered nitrate data were 

not met. More than 10 percent of the dissolved data were 

censored, and there were an insufficient number of data values 

for unfiltered nitrite.

Unfiltered total ammonia was analyzed for 1,027 samples 

collected from 1975 through 2009. Concentrations ranged 

from less than 0.01 to 2.3 mg/L with a median of 0.02 mg/L 

(table 13). More than 60 percent of the data were censored 

values. Higher concentrations (greater than 0.2 mg/L) were 

detected in only 10 percent of the samples, and most (85 percent) of these were collected before 1996. From 1996 through 

2009, about 50 percent of the concentrations greater than 

0.1 mg/L were detected in the Yampa River just downstream 

from Stagecoach Reservoir (sites 138, 158), most commonly 

during October through February. The maximum unfiltered 

total ammonia concentration of 2.3 mg/L also was detected 

at this location. Denitrification processes occurring within 

the reservoir could be contributing to the increase in ammonia downstream from the reservoir outlet. Unfiltered total 

ammonia concentrations in four samples, all collected during 

1975 or 1976 at three sites, exceeded the calculated CDPHE 

aquatic-life standard for each sample, which was 0.48 or 

0.68 mg/L. No comparison was made to the 85th percentile 

concentration for a site, because the standard for a sample 

varies depending on the pH and water temperature of the 

sample. Unfiltered total ammonia data could not be tested 

for temporal trends because more than 10 percent of the data 

were censored.

Unfiltered total phosphorous was measured for 1,581 

samples collected at 144 sites. Only about 15 percent of samples had concentrations that were less than detection levels. 

Detected concentrations ranged from 0.003 to 3.9 mg/L, and 

the median was 0.044 mg/L (table 13). For the subwatersheds, 

the median concentration was lowest (0.009 mg/L) for the 

Elk River subwatershed and highest (0.06 mg/L or more) for 

Yampa River subwatersheds 1, 3 and 4. Concentrations greater 

than 1.0 mg/L were measured in samples from Yampa River 

subwatersheds 3 and 4, which could result from naturally high 

concentrations in some sedimentary rocks. The Wadge and 

Wolf Creek coal beds of the Mesaverde Group in the UYRW 

portion of the Yampa coal field (primarily in Yampa River 

subwatershed 3 and 4) have very high contents of phosphorus 

(30 times greater than the average value for Cretaceous-age 

coal) because of ash deposits (Affolter, 2000). A seasonal pattern in unfiltered total phosphorus concentrations was evident 
Water-Quality Assessment 43

Table 13. Summary statistics for selected nutrient water-quality data and Colorado Department of Public Health and Environment 

in-stream water-quality standards for stream sampling sites in the Upper Yampa River watershed and subwatersheds, Colorado, 1975 

through 2009.—Continued

[No., number; mg/L, milligrams per liter; N, nitrogen; <, less than; --, no water-quality standard; MCL, maximum contaminant level; TVS, table value standard; 

P, phosphorus; E, estimated; nc, not computed. Number of significant figures for individual constituents may vary because data are from different sources and 

analytical periods. Water-quality standards are from Colorado Department of Public Health and Environment (2009a, 2010); standards are for aquatic-life 

protection, unless otherwise stated. See table 10 for sites in the Upper Yampa River watershed and subwatersheds with data for nutrients not in attainment of 

in-stream water-quality standards. Descriptions of stream segments are in Colorado Department of Public Health and Environment (2010). Collection of samples 

for nitrite analysis began in 1981]

Constituent

(reporting units)

No. of

sites

No. of

samples

No. of

censored

values1

Minimum

value2

Median

value

Maximum

value

In-stream

water-quality

standard

No. of sites 

with data not in 

attainment of 

standard

Upper Yampa River watershed

Nitrite, dissolved (mg/L as N) 42 628 457 <0.001 0.002 0.39 -- --

Nitrite, unfiltered (mg/L as N) 9 95 36 <0.0009 0.002 0.4 0.05 0

Nitrate, dissolved (mg/L as N) 93 1,096 360 <0.005 0.07 90 -- --

Nitrate, unfiltered (mg/L as N) 120 1,217 701 0.007 0.06 48 310 (MCL),

100 (agriculture)

0

Total ammonia, unfiltered (mg/L as N) 87 1,027 635 <0.01 0.02 2.3 3TVS or none 0

Total phosphorus, unfiltered (mg/L as P) 144 1,581 243 E 0.003 0.044 3.9 40.05, 0.1 5,618

Orthophosphate, dissolved (mg/L as P) 53 854 367 <0.001 0.01 0.22 -- --

Yampa River and tributaries upstream from Chuck Lewis State Wildlife Area

(Yampa River subwatershed 1; stream segments 2a, 2c, 3, 4, 5, 6, 7)

Nitrite, dissolved (mg/L as N) 2 101 83 <0.01 nc 0.04 -- --

Nitrite, unfiltered (mg/L as N) 4 41 16 <0.0009 0.002 0.04 0.05 0

Nitrate, dissolved (mg/L as N) 11 144 83 0.01 0.04 5 -- --

Nitrate, unfiltered (mg/L as N) 33 477 330 0.007 0.08 1.4 310 (MCL),

100 (agriculture)

0

Total ammonia, unfiltered (mg/L as N) 23 406 239 <0.01 0.03 2.3 3TVS or none 0

Total phosphorus, unfiltered (mg/L as P) 33 467 51 <0.005 0.07 0.75 40.05, 0.1 5,78

Orthophosphate, dissolved (mg/L as P) 5 107 25 <0.01 0.02 0.21 -- --

Yampa River and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence

(Yampa River subwatershed 2; stream segments 2c, 3, 20a)

Nitrite, dissolved (mg/L as N) 17 130 101 <0.001 0.002 0.02 -- --

Nitrite, unfiltered (mg/L as N) 1 9 5 <0.01 <0.01 0.02 0.05 0

Nitrate, dissolved (mg/L as N) 26 180 89 <0.005 0.02 0.9 -- --

Nitrate, unfiltered (mg/L as N) 27 155 66 0.01 0.08 0.68 10 (MCL) 0

Total ammonia, unfiltered (mg/L as N) 22 116 70 <0.01 0.01 1.9 TVS 0

Total phosphorus, unfiltered (mg/L as P) 37 242 28 <0.005 0.034 0.921 40.05, 0.1 55

Orthophosphate, dissolved (mg/L as P) 10 107 45 <0.001 0.009 0.07 -- --

Elk River and tributaries

(Elk River subwatershed; stream segments 8, 20a)

Nitrite, dissolved (mg/L as N) 8 93 63 <0.001 <0.001 0.03 -- --

Nitrite, unfiltered (mg/L as N) 2 9 6 0.001 <0.01 0.01 0.05 0

Nitrate, dissolved (mg/L as N) 13 121 23 <0.005 0.05 0.95 -- --

Nitrate, unfiltered (mg/L as N) 15 118 80 0.01 0.05 0.88 10 (MCL) 0

Total ammonia, unfiltered (mg/L as N) 9 98 78 <0.01 nc <1 TVS 0

Total phosphorus, unfiltered (mg/L as P) 20 200 76 E 0.003 0.009 0.32 40.05, 0.1 0

Orthophosphate, dissolved (mg/L as P) 10 112 55 <0.001 0.001 0.031 -- --

Yampa River and tributaries from Elk River confluence to Town of Hayden

(Yampa River subwatershed 3; stream segments 2c, 11, 12, 13a, 13b, 13c, 13e, 13f, 20a)

Nitrite, dissolved (mg/L as N) 8 122 62 <0.001 0.01 0.14 -- --

Nitrite, unfiltered (mg/L as N) 1 35 9 <0.0009 0.002 0.017 0.05 0

Nitrate, dissolved (mg/L as N) 29 373 76 <0.005 0.2 32 -- --

Nitrate, unfiltered (mg/L as N) 35 401 199 0.01 0.07 17 310 (MCL),

100 (agriculture)

0

Total ammonia, unfiltered (mg/L as N) 25 356 213 <0.01 0.02 0.83 3TVS or none 0

Total phosphorus, unfiltered (mg/L as P) 37 418 41 <0.005 0.06 2.5 40.05, 0.1 53

Orthophosphate, dissolved (mg/L as P) 18 278 82 <0.001 0.01 0.2 -- --
44 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

for Yampa River at Milner (site 151). The median concentration was highest for April, which was likely a result of the 

initial flush of snowmelt that contains phosphorus bound to 

sediments (fig. 7C). This pattern is likely present for other 

streams in the UYRW.

Concentrations of unfiltered total phosphorus in about 

14 percent (190 of 1,363) of individual samples were greater 

than USEPA recommended concentrations to control downstream eutrophication. This count excludes some stream 

segments in Yampa River subwatersheds 1, 3, and 4 because 

of naturally occurring high concentrations of phosphorus. A 

total of 59 samples from 7 sites (5 unique site locations) had 

unfiltered total phosphorus concentrations greater than 0.05 

mg/L, the recommended concentration for streams that directly 

flow into lakes and reservoirs. Concentrations in 131 individual 

samples from 31 sites (29 unique site locations) were greater 

than the recommended concentration of 0.1 mg/L for streams 

that do not directly flow into lakes and reservoirs. Fifty-one percent of concentrations greater than the recommendations were 

in samples collected during March, April, and May before and 

at the beginning of snowmelt runoff because phosphorus sorbs 

to particulate material. The 85th percentile concentration of total 

phosphorus data for 18 sites (17 unique site locations) exceeded 

the recommended concentrations of 0.05 or 0.1 mg/L; three of 

the streams flow directly into reservoirs (fig. 8, table 10). Data 

for eight of the sites were collected after 1994.

Unfiltered total phosphorus data for one site, Yampa 

River at Steamboat Springs (site 153), met the statistical 

requirements for trends testing. A statistically significant 

(p-value 0.04) trend in an upward direction was identified for 

unfiltered total phosphorus concentrations at the site for 1997 

through 2008 (fig. 11, table 9). The rate of change was small, 

Table 13. Summary statistics for selected nutrient water-quality data and Colorado Department of Public Health and Environment 

in-stream water-quality standards for stream sampling sites in the Upper Yampa River watershed and subwatersheds, Colorado, 1975 

through 2009.—Continued

[No., number; mg/L, milligrams per liter; N, nitrogen; <, less than; --, no water-quality standard; MCL, maximum contaminant level; TVS, table value standard; 

P, phosphorus; E, estimated; nc, not computed. Number of significant figures for individual constituents may vary because data are from different sources and 

analytical periods. Water-quality standards are from Colorado Department of Public Health and Environment (2009a, 2010); standards are for aquatic-life 

protection, unless otherwise stated. See table 10 for sites in the Upper Yampa River watershed and subwatersheds with data for nutrients not in attainment of 

in-stream water-quality standards. Descriptions of stream segments are in Colorado Department of Public Health and Environment (2010). Collection of samples 

for nitrite analysis began in 1981]

Constituent

(reporting units)

No. of

sites

No. of

samples

No. of

censored

values1

Minimum

value2

Median

value

Maximum

value

In-stream

water-quality

standard

No. of sites 

with data not in 

attainment of 

standard

Yampa River and tributaries from Town of Hayden to Elkhead Creek confluence

(Yampa River subwatershed 4; stream segments 2c, 12, 13d)

Nitrite, dissolved (mg/L as N) 3 3 2 <0.001 <0.001 0.39 -- --

Nitrite, unfiltered (mg/L as N) 1 1 0 0.4 0.4 0.4 0.05 0

Nitrate, dissolved (mg/L as N) 7 83 6 <0.005 0.18 90 -- --

Nitrate, unfiltered (mg/L as N) 6 36 11 0.01 0.07 48 310 (MCL), 100 

(agriculture)

0

Total ammonia, unfiltered (mg/L as N) 6 31 19 <0.01 0.02 0.31 3TVS or none 0

Total phosphorus, unfiltered (mg/L as P) 11 56 3 <0.01 0.08 3.9 40.05, 0.1 0

Orthophosphate, dissolved (mg/L as P) 4 66 24 <0.001 0.01 0.22 -- --

Elkhead Creek and tributaries

(Elkhead Creek subwatershed; stream segments 14, 15, 20b)

Nitrite, dissolved (mg/L as N) 4 179 146 E 0.003 nc 0.032 -- 0

Nitrate, dissolved (mg/L as N) 7 195 83 <0.005 0.06 1.5 -- --

Nitrate, unfiltered (mg/L as N) 4 30 15 0.01 0.06 0.52 10 (MCL) 0

Total ammonia, unfiltered (mg/L as N) 2 20 16 <0.01 nc 0.15 TVS 0

Total phosphorus, unfiltered (mg/L as P) 6 198 44 0.004 0.02 0.923 40.05, 0.1 52

Orthophosphate, dissolved (mg/L as P) 6 184 136 E 0.009 <0.01 <0.18 -- -- 1

Censored values can be expressed as values less than the laboratory reporting level.

2

For some constituents with censored data, the minimum censored value is greater than the minimum detected value that is shown.

3

Water-quality standard varies by stream segment. See Colorado Department of Public Health and Environment (2010).

4

Recommended concentration. See U.S. Environmental Protection Agency (2000). For stream segments with data for unfiltered total phosphorus, the recommended concentration has been applied to stream segments that have a standard for unfiltered nitrate.

5

Number of sites with 85th percentile concentration greater than the U.S. Environmental Protection Agency recommended concentration.

6

Seventeen unique site locations.

7

Seven unique site locations.
Water-Quality Assessment 45

about 3.1 percent per year (magnitude about 0.001 mg/L per 

year). The median concentration of unfiltered total phosphorus at the site was 0.036 mg/L. The upward trend may reflect 

population growth and related land-use changes that have 

occurred upstream from the Steamboat Springs site.

Trace Elements and Uranium

For this study, trace elements are metallic and nonmetallic elements that generally occur in small (less than 1 mg/L) 

concentrations. Many trace elements are essential nutrients 

required by biota in small amounts, but substantial concentrations of trace elements can be toxic to aquatic life and possibly to wildlife, livestock, and people (Adriano, 2001). Some 

trace elements can bioaccumulate in biota and bioconcentrate 

in the food chain. Trace-element type and concentration in 

water are often directly related to natural sources such as soils, 

geology, geochemical conditions, and the presence of thermal 

springs. Streams in mineralized areas may contain high natural 

background concentrations of metals from the oxidation and 

weathering of minerals in rocks and soils. Common anthropogenic sources of trace elements in water are the deposition 

of metals released to the atmosphere from industrial activities 

and combustion, industrial water releases (particularly acidic 

mine drainage), and urban runoff.

Trace-element data for 2,427 samples collected from 

1975 through 2009 at 145 sites in the UYRW are discussed 

in this report (tables 6, 7). Fifteen trace elements in the 

total recoverable form and (or) dissolved form are included 

(table 14). “Total recoverable” refers to that portion of a 

water and suspended-sediment sample measured by the total 

recoverable analysis procedure. Samples for trace-element 

analysis were collected almost every year in Yampa River 

subwatersheds 1 and 3. The fewest trace-element samples 

were collected in the Elkhead Creek subwatershed (table 7).

More than two-thirds of the concentrations of dissolved 

and total recoverable cadmium, lead, nickel, and silver; 

dissolved chromium, copper, selenium, and zinc; and total 

dissolved and recoverable mercury were less than detection 

levels. Concentrations greater than 1,000 micrograms per 

liter (μg/L) were reported for total recoverable aluminum, 

iron, manganese, and zinc and dissolved iron, manganese, 

and strontium. Maximum concentrations of total recoverable 

aluminum, cadmium, and nickel; dissolved and total recoverable copper, iron, lead, manganese (fig. 6E), and mercury; 

and dissolved arsenic, boron, chromium, selenium, strontium, and zinc were detected in samples from Yampa River 

subwatersheds 3 and (or) 4. Maximum concentrations of total 

recoverable arsenic, chromium, strontium, and zinc were 

detected in samples from Yampa River subwatershed 1, and 

the maximum concentration of dissolved iron was in a sample 

from Yampa River subwatershed 2. These differences can 

likely be attributed to lithologic conditions in the subwatersheds. For example, iron can be associated with sedimentary 

and iron-rich igneous intrusive rocks (Colorado Department 

of Public Health and Environment, 2008). Data collected by 

the Seneca Coal Company indicate that the weathering and 

erosion of iron-containing lithologic formations and related 

soils contributes to elevated total recoverable iron concentrations in streams in the Grassy Creek area of Yampa River 

subwatershed 3. The mean content of manganese in the Wolf 

Creek coal bed in the eastern portion of the Yampa coal field 

was almost three times the mean content in other Cretaceous 

coal beds in the Yampa coal field (Brownfield and others, 

1999). About 75 percent (89 of 118) of the samples analyzed 

Figure 11. Concentrations of flow-adjusted unfiltered total phosphorus in Yampa 

River at Steamboat Springs (site 153), Upper Yampa River watershed, Colorado, 

1997 through 2008.

1997 1999 2001 2003 2005 2007 2009

Year

0.02

0.04

0.06

0.08

0.10

0.12

Concentration of flow-adjusted

unfiltered total phosphorus,

in milligrams per liter

0
46 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009 Table 14. Summary statistics for selected trace element and uranium water-quality data and Colorado Department of Public Health and Environment in-stream water-quality standards for stream sampling sites in the Upper Yampa River watershed and subwatersheds, Colorado, 1975 through 2009.—Continued [No., number; --, no water-quality standard; <, less than; E, estimated; nc, not computed; TVS, table value standard; tr, trout; WS, water supply; SMCL, secondary maximum contaminant level; FRV, final residue value; sc, sculpin. All constituent values are reported in micrograms per liter. Number of significant figures for individual constituents may vary because data are from different sources and analytical periods. Water-quality standards are from Colorado Department of Public Health and Environment (2009a, 2010); standards are for aquatic-life protection, unless otherwise stated. Table value standards vary with stream hardness. See table 10 for sites in the Upper Yampa River watershed and subwatersheds with data for trace elements not in attainment of in-stream water-quality standards. Descriptions of stream segments are in Colorado Department of Public Health and Environment (2010)] Constituent No. of sites No. of samples No. of censored values1 Minimum value2 Median value Maximum value In-stream water-quality standard No. of sites with data not in attainment of standard Upper Yampa River watershed Aluminum, dissolved 70 588 368 6 21 570 -- -- Aluminum, total recoverable 57 355 34 <1 310 83,000 -- -- Arsenic, dissolved 86 602 362 E 0.133 0.69 13 340 (acute) 0 Arsenic, total recoverable 25 31 17 <1 <1 3 30.02, 7.6 (chronic) 0 Boron, dissolved 25 459 35 <10 60 630 750 (agriculture) 0 Cadmium, dissolved 113 1,006 957 E 0.013 nc <3 3TVS(tr) (acute), TVS (acute, chronic), none

0

Cadmium, total recoverable 33 262 208 <0.02 0.02 9.2 --4 --4Chromium, dissolved 36 154 144 <0.1 nc 50 3TVS (16 acute, 11 chronic) or none 0Chromium, total recoverable 37 231 127 E 0.568 1.5 400 3100 (chronic) or none 0

Copper, dissolved 108 960 711 E 0.175 1.0 550 3TVS (acute, chronic) or none 4Copper, total recoverable 102 977 337 E 0.403 2 510 3200 (acute) or none 0

Iron, dissolved 125 1,183 89 4 59 6,020 3300 WS (chronic, SMCL) or none 3 (WS)Iron, total recoverable 123 2,029 13 <10 420 190,000 31,000, 1,035, existing quality (chronic) 

or none

5

Lead, dissolved 108 925 883 0.04 nc 290 3TVS (acute, chronic) or none 0

Lead, total recoverable 96 545 432 E 0.03 0.46 300 3100 (chronic) or none 0

Manganese, dissolved 128 1,328 137 0.348 28 2,100 3TVS (acute, chronic),

50 WS (chronic, SMCL), none

518 (WS)

Manganese, total recoverable 102 1,496 143 E 2.2 70 4,100 3200 (chronic) or none 0

Mercury, total, dissolved 67 397 379 0.008 nc 1.2 30.01 FRV6 (chronic) or none 0

Mercury, total recoverable 93 657 554 <0.0005 nc 2.1 32.0 (acute) or none 0

Nickel, dissolved 45 135 108 <1 nc <30 3TVS (acute, chronic) or none 0Nickel, total recoverable 51 212 154 <1 2.4 280 3100, 200 (chronic) or none 0

Selenium, dissolved 108 846 689 E 0.07 nc 300 3TVS (18.4 acute, 4.6 chronic) or none 7

7

Silver, dissolved 62 636 633 <0.008 nc <3 3TVS (acute, chronic),

TVS(tr) (chronic), none

0

Silver, total recoverable 39 172 166 <0.2 nc <50 --4 --4

Strontium, dissolved 9 90 0 13 305 5,500 -- --Strontium, total recoverable 3 28 0 30 300 400 -- --Zinc, dissolved 122 1,036 708 E 0.546 1.8 960 3TVS (acute, chronic), TVS(sc) 

(chronic), none

0

Zinc, total recoverable 96 682 358 E 1.2 8.5 1,430 32,000 (chronic) or none 0

Uranium, natural, dissolved 14 51 18 0.059 1 170 830 (WS) 0
Water-Quality Assessment 47

Table 14. Summary statistics for selected trace element and uranium water-quality data and Colorado Department of Public Health and Environment in-stream water-quality standards for stream sampling sites in the Upper Yampa River watershed and subwatersheds, Colorado, 1975 through 2009.—Continued[No., number; --, no water-quality standard; <, less than; E, estimated; nc, not computed; TVS, table value standard; tr, trout; WS, water supply; SMCL, secondary maximum contaminant level; FRV, final residue value; sc, sculpin. All constituent values are reported in micrograms per liter. Number of significant figures for individual constituents may vary because data are from different sources and analytical periods. Water-quality standards are from Colorado Department of Public Health and Environment (2009a, 2010); standards are for aquatic-life protection, unless otherwise stated. Table value standards vary with stream hardness. See table 10 for sites in the Upper Yampa River watershed and subwatersheds with data for trace elements not in attainment of in-stream water-quality standards. Descriptions of stream segments are in Colorado Department of Public Health and Environment (2010)]

Constituent No. of sites No. of samples No. of censored values1 Minimum value2 Median value Maximum value In-stream water-quality standard No. of sites with data not in attainment of standard

Yampa River and tributaries upstream from Chuck Lewis State Wildlife Area

(Yampa River subwatershed 1; stream segments 2a, 2c, 3, 4, 5, 6, 7)

Aluminum, dissolved 19 196 156 6 nc 570 -- --

Aluminum, total recoverable 18 81 17 <1 105 2,500 -- --Arsenic, dissolved 22 188 98 <1 <1 5 340 (acute) 0Arsenic, total recoverable 14 19 8 <1 1 3 30.02, 0.02–10, 7.6 (chronic) 0

Boron, dissolved 1 10 0 10 25 30 750 (agriculture) 0Cadmium, dissolved 35 307 281 <0.02 nc 2 3TVS(tr) (acute), TVS (chronic), none 0Cadmium, total recoverable 19 152 124 <0.3 nc 7.4 --4 --4Chromium, dissolved 8 28 27 <1 nc <20 3TVS (16 acute, 11 chronic) or none 0Chromium, total recoverable 11 57 50 <1 nc 400 --4 --4Copper, dissolved 33 330 258 <1 1.5 <20 3TVS (acute, chronic) or none 0

Copper, total recoverable 38 534 140 <0.6 1.9 32 --4 --4Iron, dissolved 36 321 22 <10 71 1,008 3300 WS (chronic, SMCL) or none 2Iron, total recoverable 41 915 2 10 480 8,970 31,000 or none 1

Lead, dissolved 31 282 274 <0.08 nc 17 3TVS (acute, chronic) or none 0Lead, total recoverable 34 202 161 <1 nc <200 --4 --4Manganese, dissolved 37 397 14 <1 37 450 3TVS (acute, chronic),

50 WS (chronic, SMCL), none

910

Manganese, total recoverable 38 746 35 <2.8 76 1,217 --4 --4

Mercury, total, dissolved 15 64 61 <0.1 nc <0.5 30.01 FRV6 (chronic) or none 0

Mercury, total recoverable 30 184 183 <0.0005 nc <0.5 32.0 (acute) or none 0Nickel, dissolved 8 24 14 <1 <1 9 3TVS (acute, chronic) or none 0

Nickel, total recoverable 14 57 39 <1 2 <100 --4 --4Selenium, dissolved 31 236 206 <0.2 nc 7.9 3TVS (18.4 acute, 4.6 chronic) or none 1Silver, dissolved 20 208 207 <0.2 nc 2 3TVS (acute), TVS(tr) (chronic), none 0Silver, total recoverable 21 67 65 <0.2 nc <50 --4 --4Strontium, dissolved 1 12 0 240 285 400 -- --Strontium, total recoverable 2 20 0 280 315 400 -- --Zinc, dissolved 31 290 197 <0.6 3.1 700 3TVS (acute, chronic),

TVS(sc) (chronic), none

0

Zinc, total recoverable 35 201 138 <2 5.2 1,430 4-- --4Uranium, natural, dissolved 4 21 7 0.88 1 170 830 (WS) 0
48 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009 Table 14. Summary statistics for selected trace element and uranium water-quality data and Colorado Department of Public Health and Environment in-stream water-quality standards for stream sampling sites in the Upper Yampa River watershed and subwatersheds, Colorado, 1975 through 2009.—Continued [No., number; --, no water-quality standard; <, less than; E, estimated; nc, not computed; TVS, table value standard; tr, trout; WS, water supply; SMCL, secondary maximum contaminant level; FRV, final residue value; sc, sculpin. All constituent values are reported in micrograms per liter. Number of significant figures for individual constituents may vary because data are from different sources and analytical periods. Water-quality standards are from Colorado Department of Public Health and Environment (2009a, 2010); standards are for aquatic-life protection, unless otherwise stated. Table value standards vary with stream hardness. See table 10 for sites in the Upper Yampa River watershed and subwatersheds with data for trace elements not in attainment of in-stream water-quality standards. Descriptions of stream segments are in Colorado Department of Public Health and Environment (2010)] Constituent No. of sites No. of samples No. of censored values1 Minimum value2 Median value Maximum value In-stream water-quality standard No. of sites with data not in attainment of standard Yampa River and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence (Yampa River subwatershed 2; stream segments 2c, 3, 20a) Aluminum, dissolved 8 47 24 <30 34 170 -- -- Aluminum, total recoverable 6 10 0 56 505 2,600 -- -- Arsenic, dissolved 13 67 57 <1 nc 2 340 (acute) 0 Arsenic, total recoverable 4 5 4 <1 nc 1 0.02 (chronic) 0 Boron, dissolved 3 25 24 <10 nc 40 750 (agriculture) 0 Cadmium, dissolved 13 152 142 E 0.013 nc <2 TVS(tr) (acute), TVS (chronic) 0 Cadmium, total recoverable 4 5 5 <0.3 <0.3 <0.3 -- -- Chromium, dissolved 11 45 43 <0.1 nc <10 TVS (16 acute, 11 chronic) 0 Chromium, total recoverable 2 5 1 3 5.5 <10 -- -- Copper, dissolved 12 143 85 E 0.26 1.1 45.8 TVS (acute, chronic) 2 Copper, total recoverable 13 60 21 1.1 2.8 26.9 -- -- Iron, dissolved 21 106 1 17 80 6,020 300 WS (chronic, SMCL) 1 Iron, total recoverable 15 187 0 20 308 3,700 1,000 (chronic) 1 Lead, dissolved 12 139 119 E 0.04 nc 17 TVS (acute, chronic) 0 Lead, total recoverable 12 26 23 <1 nc <200 -- -- Manganese, dissolved 22 184 23 1.3 16 133 TVS (acute, chronic), 50 WS (chronic, SMCL) 105 Manganese, total recoverable 13 131 5 5 60 203 -- -- Mercury, total, dissolved 9 81 77 0.008 nc <0.5 0.01 FRV6 (chronic) 0 Mercury, total recoverable 9 43 39 <0.1 nc <0.5 -- -- Nickel, dissolved 6 20 16 <1 <1 6 TVS (acute, chronic) 0 Nickel, total recoverable 5 16 15 3 nc <50 -- -- Selenium, dissolved 13 146 122 E 0.07 nc <6 TVS (18.4 acute, 4.6 chronic) 0 Silver, dissolved 9 119 118 <0.008 nc 1 TVS (acute), TVS(tr) (chronic) 0 Silver, total recoverable 4 5 5 <0.2 <0.2 <0.2 -- -- Strontium, dissolved 2 24 0 13 23.5 43 -- -- Zinc, dissolved 21 174 101 <0.6 2.1 587 3TVS (acute, chronic), TVS(sc) (chronic) 0 Zinc, total recoverable 10 25 13 <2 13.2 40 -- -- Uranium, natural, dissolved 1 4 3 <1 <1 1 830 (WS) 0
Water-Quality Assessment 49

Table 14. Summary statistics for selected trace element and uranium water-quality data and Colorado Department of Public Health and Environment in-stream water-quality standards for stream sampling sites in the Upper Yampa River watershed and subwatersheds, Colorado, 1975 through 2009.—Continued[No., number; --, no water-quality standard; <, less than; E, estimated; nc, not computed; TVS, table value standard; tr, trout; WS, water supply; SMCL, secondary maximum contaminant level; FRV, final residue value; sc, sculpin. All constituent values are reported in micrograms per liter. Number of significant figures for individual constituents may vary because data are from different sources and analytical periods. Water-quality standards are from Colorado Department of Public Health and Environment (2009a, 2010); standards are for aquatic-life protection, unless otherwise stated. Table value standards vary with stream hardness. See table 10 for sites in the Upper Yampa River watershed and subwatersheds with data for trace elements not in attainment of in-stream water-quality standards. Descriptions of stream segments are in Colorado Department of Public Health and Environment (2010)]

Constituent No. of sites No. of samples No. of censored values1 Minimum value2 Median value Maximum value In-stream water-quality standard No. of sites with data not in attainment of standard

Elk River and tributaries

(Elk River subwatershed; stream segments 8, 20a)

Aluminum, dissolved 12 107 40 11.1 34 260 -- --Aluminum, total recoverable 10 67 8 E 19.0 112 6,612 -- --Arsenic, dissolved 13 83 64 E 0.133 nc 2 340 (acute) 0Arsenic, total recoverable 2 2 2 <1 <1 <1 0.02 (chronic) 0Boron, dissolved 1 1 1 <16 <16 <16 750 (agriculture) 0Cadmium, dissolved 18 155 152 <0.02 nc <2 TVS(tr) (acute), TVS (chronic) 0Cadmium, total recoverable 3 21 18 <0.3 nc 2.9 -- --Chromium, total recoverable 2 24 23 <1 nc <20 -- --Copper, dissolved 18 154 108 E 0.175 0.71 5.3 TVS (acute, chronic) 1Copper, total recoverable 15 98 46 E 0.403 1 20 -- --Iron, dissolved 17 127 1 E 6.4 54 420 300 WS (chronic, SMCL) 0Iron, total recoverable 19 182 3 14 150 10,030 1000 (chronic) 0Lead, dissolved 18 152 143 E 0.04 nc 13 TVS (acute, chronic) 0Lead, total recoverable 15 98 65 E 0.03 0.31 <200 -- --Manganese, dissolved 18 156 55 0.348 2.8 650 TVS (acute, chronic),

50 WS (chronic, SMCL)

0

Manganese, total recoverable 15 110 26 E 2.2 10 960 -- --Mercury, total, dissolved 9 42 41 <0.1 nc <0.5 0.01 FRV6 (chronic) 0

Mercury, total recoverable 14 94 86 E 0.009 nc <0.5 -- --Nickel, dissolved 4 10 10 <1 nc <2 TVS (acute, chronic) 0Nickel, total recoverable 7 27 23 <1 nc <100 -- --Selenium, dissolved 12 88 86 <1 nc <5 TVS (18.4 acute, 4.6 chronic) 0Silver, dissolved 12 105 105 <0.2 nc <1 TVS (acute), TVS(tr) (chronic) 0Silver, total recoverable 4 17 17 <0.2 nc <50 -- --Strontium, dissolved 1 1 0 20.1 20.1 20.1 -- --Strontium, total recoverable 1 8 0 30 65 110 -- --Zinc, dissolved 18 158 120 E 0.546 1.05 52 3TVS (acute, chronic),

TVS(sc) (chronic)

0

Zinc, total recoverable 15 98 66 E 1.20 3.6 100 -- --Uranium, natural, dissolved 4 12 4 0.059 0.499 6 830 (WS) 0
50 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009 Table 14. Summary statistics for selected trace element and uranium water-quality data and Colorado Department of Public Health and Environment in-stream water-quality standards for stream sampling sites in the Upper Yampa River watershed and subwatersheds, Colorado, 1975 through 2009.—Continued [No., number; --, no water-quality standard; <, less than; E, estimated; nc, not computed; TVS, table value standard; tr, trout; WS, water supply; SMCL, secondary maximum contaminant level; FRV, final residue value; sc, sculpin. All constituent values are reported in micrograms per liter. Number of significant figures for individual constituents may vary because data are from different sources and analytical periods. Water-quality standards are from Colorado Department of Public Health and Environment (2009a, 2010); standards are for aquatic-life protection, unless otherwise stated. Table value standards vary with stream hardness. See table 10 for sites in the Upper Yampa River watershed and subwatersheds with data for trace elements not in attainment of in-stream water-quality standards. Descriptions of stream segments are in Colorado Department of Public Health and Environment (2010)] Constituent No. of sites No. of samples No. of censored values1 Minimum value2 Median value Maximum value In-stream water-quality standard No. of sites with data not in attainment of standard Yampa River and tributaries from Elk River confluence to Town of Hayden (Yampa River subwatershed 3; stream segments 2c, 11, 12, 13a, 13b, 13c, 13e, 13f, 20a) Aluminum, dissolved 23 172 111 8 18 <250 -- -- Aluminum, total recoverable 15 119 9 <1 1,500 68,000 -- -- Arsenic, dissolved 26 162 78 0.4 1 13 340 (acute) 0 Arsenic, total recoverable 4 4 2 <1 <1 2 30.02, 7.6 0 Boron, dissolved 12 345 8 <10 60 630 750 (agriculture) 0 Cadmium, dissolved 33 265 260 <0.02 nc <3 3TVS(tr) (acute), TVS (acute, chronic), none

0

Cadmium, total recoverable 4 81 58 <0.02 0.03 9.2 --4 --4Chromium, dissolved 14 44 39 <0.8 nc 50 3TVS (16 acute, 11 chronic), none 0Chromium, total recoverable 14 80 30 <0.8 6 54 3100 (chronic) or none 0

Copper, dissolved 32 218 207 <1 nc 550 3TVS (acute, chronic) or none 1Copper, total recoverable 23 182 110 <0.6 3.0 510 3200 (acute) or none 0

Iron, dissolved 37 446 45 4 50 2,300 3300 WS (chronic, SMCL) or none 0Iron, total recoverable 32 522 8 <10 460 190,000 31,000, 1,035,

existing quality (chronic) or none

3

Lead, dissolved 34 237 234 <0.08 nc <30 3TVS (acute, chronic) or none 0

Lead, total recoverable 22 158 139 <1 nc 300 3100 (chronic) or none 0Manganese, dissolved 37 394 29 <4 50 1,500 3TVS (acute, chronic),

50 WS (chronic, SMCL), none

3

Manganese, total recoverable 23 331 71 <2.8 120 4,100 3200 (chronic) or none 0Mercury, total, dissolved 24 130 126 <0.01 nc 1.2 30.01 FRV6 (chronic) or none 0

Mercury, total recoverable 26 214 154 <0.0005 0.06 2.1 -- --Nickel, dissolved 19 51 51 <1 nc <30 3TVS (acute, chronic) or none 0

Nickel, total recoverable 18 62 62 <1 nc <100 3200 (chronic) or none 0Selenium, dissolved 38 247 178 <0.4 <1 290 3TVS (18.4 acute, 4.6 chronic) or none 114Silver, dissolved 14 119 118 <0.06 nc <3 3TVS (acute, chronic),

TVS(tr) (chronic), none

0

Silver, total recoverable 7 46 42 <0.2 nc <50 -- --Strontium, dissolved 3 38 0 290 1,020 5,500 -- --Zinc, dissolved 38 289 208 <0.6 1.1 280 3TVS (acute, chronic),

TVS(sc) (chronic), none

0

Zinc, total recoverable 22 261 103 <2 20 1,000 32,000 (chronic) or none 0

Uranium, natural, dissolved 4 13 4 <1 1 4 830 (WS) 0
Water-Quality Assessment 51

Table 14. Summary statistics for selected trace element and uranium water-quality data and Colorado Department of Public Health and Environment in-stream water-quality standards for stream sampling sites in the Upper Yampa River watershed and subwatersheds, Colorado, 1975 through 2009.—Continued[No., number; --, no water-quality standard; <, less than; E, estimated; nc, not computed; TVS, table value standard; tr, trout; WS, water supply; SMCL, secondary maximum contaminant level; FRV, final residue value; sc, sculpin. All constituent values are reported in micrograms per liter. Number of significant figures for individual constituents may vary because data are from different sources and analytical periods. Water-quality standards are from Colorado Department of Public Health and Environment (2009a, 2010); standards are for aquatic-life protection, unless otherwise stated. Table value standards vary with stream hardness. See table 10 for sites in the Upper Yampa River watershed and subwatersheds with data for trace elements not in attainment of in-stream water-quality standards. Descriptions of stream segments are in Colorado Department of Public Health and Environment (2010)]

Constituent No. of sites No. of samples No. of censored values1 Minimum value2 Median value Maximum value In-stream water-quality standard No. of sites with data not in attainment of standard

Yampa River and tributaries from Town of Hayden to Elkhead Creek confluence

(Yampa River subwatershed 4; stream segments 2c, 12, 13d)

Aluminum, dissolved 6 47 27 8 12 <250 -- --Aluminum, total recoverable 5 41 0 130 2,200 83,000 -- --Arsenic, dissolved 6 43 18 <1 1 4 340 (acute) 0Boron, dissolved 4 66 0 50 80 590 750 (agriculture) 0Cadmium, dissolved 8 47 43 <0.02 nc <2 3TVS(tr) (acute),

TVS (acute, chronic), none

0

Chromium, dissolved 1 1 1 <0.8 <0.8 <0.8 3TVS (16 acute, 11 chronic), none 0Chromium, total recoverable 6 29 3 <0.8 4 30 3100 (chronic) or none 0

Copper, dissolved 7 42 27 1.1 1.9 60 3TVS (acute, chronic) or none 0Copper, total recoverable 5 55 6 <0.6 5.9 250 3200 (acute) or none 0

Iron, dissolved 8 107 14 <10 40 1,718 3300 WS (chronic, SMCL) or none 0

Iron, total recoverable 10 145 0 50 690 190,000 31,000, existing quality

(chronic) or none

0

Lead, dissolved 7 38 37 <0.08 nc 290 3TVS (acute, chronic) or none 0

Lead, total recoverable 5 12 11 <1 nc <200 3100 (chronic) or none 0Manganese, dissolved 8 109 2 5 30 2,100 3TVS (acute, chronic),

50 WS (chronic, SMCL), none

0

Manganese, total recoverable 7 119 0 20 80 3,300 3200 (chronic) or none 0

Mercury, total, dissolved 5 22 21 <0.01 nc <0.5 30.01 FRV6 (chronic) or none 0Mercury, total recoverable 8 64 40 <0.0005 0.08 <0.5 -- --Nickel, dissolved 3 10 10 <1 nc <2 3TVS (acute, chronic) or none 0

Nickel, total recoverable 2 6 5 <50 nc 280 3200 (chronic) or none 0

Selenium, dissolved 7 47 23 <0.4 1 300 3TVS (18.4 acute, 4.6 chronic) or none 2Silver, dissolved 3 26 26 <0.2 nc <0.5 3TVS (acute, chronic),

TVS(tr) (chronic), none

0

Zinc, dissolved 7 43 18 <0.6 10 960 3TVS (acute, chronic), TVS(sc), none 0

Zinc, total recoverable 6 50 6 <2 40 890 32,000 (chronic) or none 0Uranium, natural, dissolved 1 1 0 4 4 4 830 (WS) 0

Elkhead Creek and tributaries

(Elkhead Creek subwatershed; stream segments 14, 15, 20b)

Aluminum, dissolved 2 19 10 <15 46 190 -- --Aluminum, total recoverable 3 37 0 50.5 390 9,063 -- --Arsenic, dissolved 6 59 47 <1 nc <5 340 (acute) 0Arsenic, total recoverable 1 1 1 <1 <1 <1 0.02 (chronic) 0Boron, dissolved 3 12 2 <10 20 60 750 (agriculture) 0Cadmium, dissolved 6 80 79 <0.04 nc <2 TVS(tr) (acute), TVS (chronic) 0
52 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009 Table 14. Summary statistics for selected trace element and uranium water-quality data and Colorado Department of Public Health and Environment in-stream water-quality standards for stream sampling sites in the Upper Yampa River watershed and subwatersheds, Colorado, 1975 through 2009.—Continued [No., number; --, no water-quality standard; <, less than; E, estimated; nc, not computed; TVS, table value standard; tr, trout; WS, water supply; SMCL, secondary maximum contaminant level; FRV, final residue value; sc, sculpin. All constituent values are reported in micrograms per liter. Number of significant figures for individual constituents may vary because data are from different sources and analytical periods. Water-quality standards are from Colorado Department of Public Health and Environment (2009a, 2010); standards are for aquatic-life protection, unless otherwise stated. Table value standards vary with stream hardness. See table 10 for sites in the Upper Yampa River watershed and subwatersheds with data for trace elements not in attainment of in-stream water-quality standards. Descriptions of stream segments are in Colorado Department of Public Health and Environment (2010)] Constituent No. of sites No. of samples No. of censored values1 Minimum value2 Median value Maximum value In-stream water-quality standard No. of sites with data not in attainment of standard Elkhead Creek and tributaries (Elkhead Creek subwatershed; stream segments 14, 15, 20b)—Continued Cadmium, total recoverable 3 3 3 <0.3 <0.3 <0.3 -- -- Chromium, dissolved 2 36 34 E 0.507 nc 5.5 TVS (16 acute, 11 chronic) 0 Chromium, total recoverable 2 36 20 E 0.568 1.32 10.0 -- -- Copper, dissolved 6 73 26 E 0.856 1.7 <5 TVS (acute, chronic) 0 Copper, total recoverable 8 48 14 <1 2.23 23.1 -- -- Iron, dissolved 6 76 6 6 30.5 620 300 WS (chronic, SMCL) 0 Iron, total recoverable 6 78 0 30 428 17,690 1,000 (chronic) 0 Lead, dissolved 6 77 76 E 0.048 nc <5 TVS (acute, chronic) 0 Lead, total recoverable 8 49 33 E 0.539 1.09 <200 -- -- Manganese, dissolved 6 88 14 <1 10 100 TVS (acute, chronic), 50 WS (chronic, SMCL)

0

Manganese, total recoverable 6 59 6 8.46 37 523 -- --Mercury, total, dissolved 5 58 53 <0.01 nc <0.5 0.01 FRV6 (chronic) 0

Mercury, total recoverable 6 58 52 <0.011 nc <0.5 -- --Nickel, dissolved 5 20 7 <1 2 3 TVS (acute, chronic) 0Nickel, total recoverable 5 44 10 E 1.31 2.85 <50 -- --Selenium, dissolved 7 82 74 <0.4 nc <5 TWS (18.4 acute, 4.6 chronic) 0Silver, dissolved 4 59 59 <0.1 nc <2 TVS (acute), TVS(tr) (chronic) 0Silver, total recoverable 3 37 37 <0.2 nc <1 -- --Strontium, dissolved 2 15 0 130 270 503 -- --Zinc, dissolved 7 82 64 <0.6 2.1 28 TVS (acute, chronic) 0Zinc, total recoverable 8 47 32 <2 9.5 68.8 -- -- 1Censored values can be expressed as values less than the laboratory reporting level.

2For some constituents with censored data, the minimum censored value is greater than the minimum detected value that is shown.3Water-quality standard varies by stream segment. See Colorado Department of Public Health and Environment (2010).4No data were available for stream segment(s) listed in appendix 2 that have a Colorado Department of Public Health and Environment water-quality standard for the constituent of interest.5Sixteen unique site locations.6Final Residue Value (FRV) is the maximum allowed concentration of total mercury in water that will present bioaccumulation or bioconcentration of methylmercury in edible fish tissue (Colorado 

Department of Public Health and Environment, 2009a).

7Six unique site locations.8Uranium level in surface water used for water supply shall be maintained at the lowest practical level. The maximum allowed concentration in water used for supply is 30 micrograms per liter, unless 

naturally occurring concentrations are greater (Colorado Department of Public Health and Environment, 2009a).

9Nine unique site locations.10Four unique site locations.11Three unique site locations.
Water-Quality Assessment 53

for dissolved and total recoverable strontium had concentrations greater than the 60 μg/L, which is the median strontium 

concentration for major rivers in North America (Hem, 1992). 

Concentrations greater than 60 μg/L were present in samples 

from every subwatershed except Yampa River subwatershed 

4, and no strontium data were available for this subwatershed (table 14). The Wadge and Wolf Creek coal beds in the 

Yampa coal field have high contents of strontium (30 times 

greater than the average value for Cretaceous-age coal) 

(Affolter, 2000).

Seasonal variation in trace-element concentrations was 

evident for total recoverable concentrations of aluminum, 

copper, iron, and zinc for Yampa River at Milner (site 151) 

(fig. 7D), which is likely representative of other sites. The 

highest 5 to 10 percent of the concentration values of all four 

trace elements were detected in April and May. Concentrations were elevated during the initial pulse of snowmelt runoff, 

and to a lesser extent later in the snowmelt period, as a result 

of particulate-phase trace elements binding to sediment as 

material is washed off the land surface. The seasonal variation in total recoverable manganese concentrations was less 

evident. The seasonal pattern in dissolved iron concentrations 

was similar to that of total recoverable iron. For other dissolved trace elements, a seasonal pattern in concentrations was 

not visually discernible. Sufficient data for trend testing were 

available only for total recoverable iron and dissolved and 

total recoverable manganese for Yampa River at Steamboat 

Springs (site 153). No statistically significant trends (p-values 

0.53, 0.17) were identified for total recoverable iron or dissolved manganese for data collected from 1997 through 2008. 

A statistically significant downward trend (p-value 0.03) was 

identified for concentrations of total recoverable manganese 

in samples collected from 1997 through 2008 (table 9). The 

rate of change was small, 4.6 percent per year (magnitude of 

2.6 μg/L per year). The median concentration of total recoverable manganese at the site was 45.6 μg/L.

Concentrations of dissolved cadmium, manganese, 

selenium, and silver; dissolved and total recoverable arsenic, 

chromium, copper, lead, nickel, and zinc; and total recoverable iron and mercury were compared to CDPHE standards 

for the protection of aquatic life (table 14, appendix 2). Dissolved boron concentrations were compared to the CDPHE 

agricultural-use standard. Concentrations of total dissolved 

mercury were compared to the final residue value, which is the 

maximum allowed concentration of total mercury in water that 

will present bioaccumulation or bioconcentration of methylmercury in edible fish tissue (Colorado Department of Public 

Health and Environment, 2009a). Although concentrations of 

some trace elements in individual samples were greater than 

the CDPHE standards, about 90 percent (130 of 145) of stream 

sites with trace element data were in attainment of standards 

for dissolved boron, cadmium, manganese, and silver; dissolved and total recoverable arsenic, chromium, lead, mercury, 

nickel, and zinc; and total recoverable copper because the 

50th (total recoverable) and 85th (dissolved) percentiles of the 

concentration data for a trace element at a particular site were 

less than the respective standard.

A total of 15 sites (14 unique site locations) with data for 

dissolved copper, total recoverable iron, and (or) dissolved 

selenium were not in attainment of the respective CDPHE 

aquatic-life standards (fig. 12, table 10). All data for 11 of 15 

sites were collected before 1999. Attainment of the standard for dissolved copper was not met for four sites (fig. 12, 

table 10). The two sites in the Yampa River subwatershed 2 

and the one site in the Elk River subwatershed naturally have 

low hardness; mean hardness for the three sites was 15 mg/L 

or less. Because aquatic-life standards for many trace elements are hardness dependent, extremely low hardness for a 

sample results in a smaller value for the standard compared to 

a sample with harder water. The CDPHE aquatic-life standard 

for total recoverable iron was not met for five sites, all data 

at these sites were collected before 1999 (fig. 12, table 10). 

Nonattainment of the standard prior to 1999 may not be a 

current issue of concern; attainment of the standard was met 

for all sites that had total recoverable iron data collected 

after 1998. Individual samples with total recoverable iron 

concentration greater than the standard were most commonly 

collected from March through May when increased sediment 

load would be carried in streams with the flush of snowmelt 

runoff. The CDPHE chronic aquatic-life standard for dissolved 

selenium of 4.6 μg/L was not met for seven sites (six unique 

site locations); the acute standard of 18.4 μg/L was not met for 

six of the seven sites (fig. 12, table 10). All sites but one are 

in Yampa River subwatersheds 3 and 4, portions of which are 

underlain by seleniferous Lewis Shale.

Attainment of the CDPHE water-supply standards for 

dissolved iron and (or) dissolved manganese were not met at a 

total of 19 sites overall (17 unique site locations). Three sites 

in Yampa River subwatersheds 1 or 2 were not in attainment 

of the CDPHE water-supply standard for dissolved iron, and 

18 sites (16 unique sites) in Yampa River subwatershed 1, 2, 

or 3 were not in attainment of the water-supply standard for 

dissolved manganese (fig. 12, table 10). Elevated concentrations of dissolved iron and manganese could be the result of 

lithologic conditions or possible reduction-oxidation processes 

that may occur in groundwater. Iron is the fourth most abundant element in the Earth’s crust (Lutgens and others, 2012). 

It is associated with a variety of minerals in igneous and sedimentary rocks and is present in organic materials. Manganese 

commonly is in the same minerals as iron (Driver and others, 

1984). As a result, large amounts of iron and manganese can 

be common in surface water and groundwater.

Two nonreservoir stream segments in the UYRW are on 

the state of Colorado 2012 303(d) list of impaired waters for 

nonattainment of aquatic-life standards because of trace element contamination (Colorado Department of Public Health 
54 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Figure 12. Location of water-quality sampling sites with exceedances of Colorado Department of Public Health and 

Environment in-stream water-quality standards for trace elements, Upper Yampa River watershed, Colorado, 1975 

through 2009. 

#

#

#

#

#

#

#

## #

##

# ##

#

#

#

#

#

#

#

# ##

#

#

#

16

17

45

49

51

63 83 91

101

115

117

122

124

129

140

143

153

164

166

168

171

138,139,158

22

112

59

98

170

123

Base from U.S. Geological Survey digital data,

1:100,000, Universal Transverse Mercator, 

Zone 13 North, North American Datum of 1983

0 5 10 MILES

0 5 10 KILOMETERS

166#

Water-Quality Standard

Aquatic-life

standard

Water-supply

standard

Dissolved copper

Total recoverable iron

Dissolved selenium

Dissolved iron

Dissolved manganese

EXPLANATION

Streamwater sampling site

 and site number

Sample collected before 1996

Sample collected during and after 1996

Steamboat

Springs

Pearl

Lake

Streamboat Lake

Lake

Elbert

Fish Creek

Reservoir

Long Lake

Reservoir

Lake Catamount

Yamcolo

Reservoir

Stillwater

Reservoir

Stillwater

Reservoir

Long Lake

Reservoir

Long Lake

Reservoir

Stagecoach

Reservoir

Lost Dog Creek

Elk

River

Ma d Creek

Yampa River

Fish CreekFish Creek

Service Creek

Walton Creek

Morrison Creek

Bushy Cr

Yampa Riv er Yampa Riv er

Little

Morrison

Creek

Bear River

Trout Creek

Foidel Cree

Gr

k

assy Cre ek

Fish Creek

Sage Creek

Wolf Cr

YampaRiverYampaRiver

Dry Creek

Elkhea d CrElkhea d Cr Elkhead

Reservoir

First CreekFirst Creek

Oak Creek

Yampa River

subwatershed 4

Yampa River

subwatershed 1

Yampa River

subwatershed 3 Yampa River

subwatershed 3

Yampa River

subwatershed 3

Yampa River

subwatershed 2

Elk River

subwatershed

Elkhead Creek

subwatershed

40°30'

40°15'

40°00'

40°45'

107°15'

107°00'

106°45'
Water-Quality Assessment 55

and Environment, 2012). All or a portion of segment 13d for 

Dry Creek is listed for total recoverable iron (snowmelt season) or selenium, and a portion of Sage Creek in segment 13e 

is listed for selenium (table 5) . Elkhead Creek is provisionally 

listed for aquatic life (table 5) (Colorado Department of Public 

Health and Environment, 2012). Portions of four stream segments are on the state of Colorado monitoring and evaluation 

list for dissolved iron and lead, manganese, mercury, selenium, 

or zinc contamination (table 5) (Colorado Department of 

Public Health and Environment, 2012).

Uranium, a radiochemical, is a human carcinogen that 

also can be harmful to kidneys (U.S. Environmental Protection 

Agency, 2012a). Water-quality samples collected from streams 

in the UYRW were infrequently analyzed for uranium. Dissolved uranium data were available for only 51 samples 

collected at 14 sites, most commonly in Yampa River subwatersheds 1 and 3 and the Elk River subwatershed (table 7). 

Detected concentrations of dissolved uranium ranged from 

0.059 to 170 μg/L (table 14). About 35 percent of the uranium 

data were censored at detection levels of 1 or 5 μg/L. Attainment of the CDPHE water-supply standard of 30 μg/L was 

met for all sites with uranium data; the 85th percentile of the 

concentration data for each of the 12 sites with uranium data 

was less than 30 μg/L.

Uranium is an important source of radon gas, another 

human carcinogen. The potential for radon in indoor air 

increases with higher concentrations of uranium in rocks 

(U.S. Environmental Protection Agency, 2012b). The USEPA 

has assigned Garfield, Moffat, and Rio Blanco Counties to the 

radon-potential category of 1, signifying a high potential for 

elevated indoor radon levels (U.S. Environmental Protection 

Agency, 2010a). Routt County is in the radon-potential category of 2 and has a moderate potential for elevated indoor 

radon levels. In the UYRW database, no water-quality data for 

radon were available for analysis.

Coliform Bacteria

Coliforms are bacteria present in the digestive tracts of 

warm-blooded animals and in soil and vegetation. The bacteria 

are not likely to cause illness themselves, but their presence in 

water indicates that disease-causing pathogens could also be in 

the water. Total coliform consists of a large group of different 

types of bacteria. Fecal coliforms are bacteria that are present 

in the feces and intestines of warm-blooded animals. Their 

presence in water indicates recent contamination by animal 

waste or sewage. Escherichia coli (E. coli) are a subgroup of 

fecal coliform bacteria and are the only coliform group with a 

CDPHE water-quality standard for recreational use of water. 

The numeric value of the standard varies by stream segment. 

Potential sources of fecal coliform in the UYRW include, but 

are not limited to, recreational water users, wildlife, livestock, 

and septic systems. Concentrations of fecal coliforms are typically affected by, but not limited to, temperature, salinity, light 

intensity, rainfall, and streamflow (Chigbu and Sobeler, 2007).

In the UYRW, data for coliform bacteria (total, fecal, 

and E. coli) were available for 432 samples collected from 89 

stream sites (table 6) during 1975 and 1976 and 1989 through 

2009 (table 7). Samples were collected most frequently and 

from the greatest number of stream sites in Yampa River 

subwatershed 2. The fewest samples and sites were in Yampa 

River subwatershed 4.

Total coliform data were available for 119 samples 

collected during 1975 and 1976 at 43 sites, primarily in 

Yampa River subwatershed 2. Concentrations ranged from no 

detection to 18,000 colonies per 100 milliliters (col/100 mL) 

(table 15); about 80 percent (95 of 119) of the concentrations 

were less than 400 col/100 mL. Most (20 of 24) concentrations of 400 col/100 mL or more were detected in samples 

from Yampa River subwatershed 2. Fecal coliform data were 

available for 399 samples collected from 88 sites in multiple subwatersheds (table 15). Collection dates were during 

1975,1976, and most years from 1989 through 2008. About 

95 percent (378 of 399) of the fecal coliform concentrations 

were less than 200 col/100 mL. Water-quality standards have 

not been established for total and fecal coliform.

A total of 122 samples collected at 6 sites from 1991 

through 2009 were analyzed for E. coli. Concentrations ranged 

from less than 1 to 733 col/100 mL, and the median was 

18 col/100 mL (table 15). Recent (2000 through 2009) E. coli

data are from samples collected at Elk River near Milner, 

Colo. (site 33), Fish Creek at Upper Station (site 49),Yampa 

River at Steamboat Springs (site 153), and two Elkhead Creek 

sites (sites 40, 42). The 2010 CDPHE recreation standard for 

E. coli of 126 col/100 mL was exceeded in five samples collected during 1994, 1999, 2001, and 2003. Two samples were 

from Yampa River at Steamboat Springs (site 153), and three 

samples were from two Elkhead Creek sites (sites 40, 42). The 

Yampa River in the vicinity of Steamboat Springs is heavily 

used for recreation during summer, and the Elkhead Creek 

subwatershed has a high percentage of rangeland and pasture. 

No sites with an E. coli standard of 205 or 630 col/100 mL 

were sampled. Attainment of the E. coli standard is based on 

the geometric mean of representative stream samples. For 

this study, an insufficient number of E. coli samples were 

collected to calculate geometric means for comparison to the 

standard of 126 col/100 mL. Comparison of individual E. coli

concentrations to the standard, however, can give a general 

indication of water quality in streams where the bacteria are 

present. Portions of three stream segments in the UYRW are 

on the CDPHE 303(d) list of impaired waters or monitoring 

and evaluation list for E. coli (table 5) (Colorado Department 

of Public Health and Environment, 2012).

Suspended Sediment

Suspended sediment or suspended solids are very fine 

particles suspended in water for a substantial time period without settling. This includes silt and soil from erosion and storm 

and urban runoff; remains from the breakdown of terrestrial 
56 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Table 15. Summary statistics for selected coliform bacteria water-quality data and Colorado Department of Public Health and 

Environment in-stream water-quality standards for stream sampling sites in the Upper Yampa River watershed and subwatersheds, 

Colorado, 1975, 1976, and 1989 through 2009.

[No., number; --, no standard; <, less than. All coliform values are reported in colonies per 100 milliliters. Water-quality standards are from Colorado Department 

of Public Health and Environment (2009a, 2010). Descriptions of stream segments are in Colorado Department of Public Health and Environment (2010)]

Coliform bacteria No. of

sites

No. of

samples

No. of

censored

values1

Minimum

value

Median

value

Maximum

value

In-stream

water-quality

standard

No. of samples with 

data exceeding 

standard

Upper Yampa River watershed

Total coliform 43 119 12 0 60 18,000 -- --

Fecal coliform 88 399 52 0 14 2,100 -- --

Escherichia coli 6 122 5 <1 18 733 2

126/100 5

Yampa River and tributaries upstream from Chuck Lewis State Wildlife Area

(Yampa River subwatershed 1; stream segments 2a, 2c, 3, 4, 5, 6, 7)

Total coliform 9 29 2 <1 20 750 -- --

Fecal coliform 20 102 29 <1 4 560 -- --

Yampa River and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence

(Yampa River subwatershed 2; stream segments 2c, 3, 20a)

Total coliform 19 59 4 <1 92 18,000 -- --

Fecal coliform 32 150 11 0 15 1,800 -- --

Escherichia coli 2 64 6 <1 12 177 126/100 2

Elk River and tributaries

(Elk River subwatershed; stream segments 8, 20a)

Total coliform 5 16 5 <1 4 1,700 -- --

Fecal coliform 8 34 7 <1 2 1,200 -- --

Escherichia coli 1 6 0 7 22 108 126/100 0

Yampa River and tributaries from Elk River confluence to Town of Hayden

(Yampa River subwatershed 3; stream segments 2c, 11, 12, 13a, 13b, 13c, 13e, 13f, 20a)

Total coliform 7 7 0 0 96 200 -- --

Fecal coliform 18 32 2 0 13 133 -- --

Yampa River and tributaries from Town of Hayden to Elkhead Creek confluence

(Yampa River subwatershed 4; stream segments 2c, 12, 13d)

Total coliform 1 1 0 210 210 210 -- --

Fecal coliform 4 12 0 2 14 261 -- --

Elkhead Creek and tributaries

(Elkhead Creek subwatershed; stream segments 14, 15, 20b)

Total coliform 2 7 1 <1 24 190 -- --

Fecal coliform 6 69 3 <1 29 2,100 -- --

Escherichia coli 3 52 0 1 21 733 126/100 3 1

Censored values can be expressed as values less than the laboratory reporting level.

2

No Escherichia coli data were available for stream segments with standards of 205 or 630 colonies per 100 milliliters.

and aquatic biota; and wastes from industry and watertreatment plants (Murphy, 2007b). The amount and size of 

suspended sediment in water are affected by streamflow. More 

and larger suspended material can be carried in water with 

a higher streamflow than with a lower streamflow (fig. 13). 

Because phosphorus adsorbs to the surface of sediment, phosphorus concentrations are higher when suspended-sediment 

concentrations are higher (fig. 13). In the UYRW, a total of 

1,079 suspended-sediment samples were collected from 65 

sites during most years from 1975 through 2003 (tables 6, 7). 

Sample collection occurred after 1992 only in the Elk River 

and Elkhead Creek subwatersheds. Suspended-sediment concentrations typically were lowest from August through February when streamflow was lowest. Concentrations typically 

were higher during May in the Elk River and Elkhead Creek 

subwatersheds and during April in other subwatersheds. The 

highest concentrations (greater than 2,000 mg/L) were in samples collected from streams in areas with sedimentary rocks, 

especially Yampa River subwatersheds 3 and 4 (table 16).

Lakes and Reservoirs

The UYRW water-quality database contains data for 42 

lake and reservoir sites in 30 bodies of water for 369 sample 

days for the period 1975 through 2009 (table 3). Sites with 

different names and identifiers in the database but with the 

same latitude and longitude are counted as one site. Samples 
Water-Quality Assessment 57

collected at multiple depths on the same day are counted as 

a one sample day. For 26 of the lake and reservoir sites in 16 

bodies of water, data were collected for a maximum of 4 sample days, all before 1986; about one-half of these sites were 

described as potholes or ponds. Data also were available for 

16 sites and 327 samples collected on 180 sample days from 5 

lakes and reservoirs for the period 1983 through 2009 (appendix 4). The analysis of lake and reservoir data was restricted 

to these five water bodies because data collection was long 

term (greater than 10 years) and (or) occurred after 1994. Lake 

Elbert and Long Lake Reservoir (fig. 1), high-altitude lakes in 

and near the Mount Zirkel Wilderness Area north and east of 

Steamboat Springs, are long-term data-collection sites. Samples analyzed for this study were collected from Lake Elbert 

on 74 sample days from 1985 through 2009 and from Long 

Lake Reservoir on 64 sample days from 1985 through 2005. 

Samples were collected in Stagecoach Reservoir on 43 sample 

days at 5 sites during 1990 through 1992 and July 2006. Data 

for Steamboat Lake were available for only one sample day in 

July 2006. Samples were collected in Elkhead Reservoir on 18 

days at 8 sites from July 1995 through August 2001.

Lake and reservoir sites were grouped for analysis on 

the basis of site and data similarities. Data for Lake Elbert 

and Long Lake Reservoir were analyzed together. Analysis 

of data for Stagecoach Reservoir was limited to samples 

collected on July 25, 2006, at one site. These data were 

compared to data collected in Steamboat Lake on the same 

day. Water quality of Elkhead Reservoir was analyzed in 

detail by Kuhn and others (2003) and is summarized later in 

this subsection.

Lake Elbert and Long Lake Reservoir were sampled 

two-to-five times per year during the open-water season, and 

grab samples were collected manually from the shore at locations with little or no vegetation (Mast and others, 2005). One 

sample per day for each reservoir was analyzed for this study. 

Both lakes were very dilute. Median specific conductance values for near-surface samples were 10.6 μS/cm for Lake Elbert 

and 18.3 μS/cm for Long Lake Reservoir (table 17). All values 

were 34 μS/cm or less, which reflects the igneous-rock composition in the drainage basins of the water bodies. Specific 

conductance in both water bodies typically was lower during 

snowmelt runoff when lake water was diluted than during 

summer when groundwater discharge had a greater effect on 

water chemistry. Median values of pH near the water surface 

were similar (7.1 and 7.2) for the two water bodies. On three 

samples days for Long Lake Reservoir, values of pH in three 

near-surface water samples were less than the CDPHE waterquality minimum standard of 6.5 for aquatic-life protection. 

Two samples from Long Lake Reservoir had dissolved oxygen 

concentrations equal to 0.2 mg/L. Hardness, ANC, and sulfate 

concentrations were slightly higher in Long Lake Reservoir 

than in Lake Elbert, reflecting differences in biogeochemistry 

of the two water bodies and the quality of the shallow groundwater system underlying the water bodies (Mast and others, 

2005). Low ANC (17.9 mg/L or less) indicates that both water 

bodies are sensitive to acidic deposition. A statistically significant decrease in sulfate concentrations in Lake Elbert has been 

observed for the period 1985 through 2008 (Mast and others, 

2011). This decrease has been driven by reductions in sulfur 

dioxide emissions from a nearby upwind power plant and a 

related decrease in atmospheric deposition of sulfate (Mast 

and others, 2011). Most (123 of 136) nitrate concentrations in 

near-surface samples from both water bodies were less than 

detection levels. Mast and others (2005) report that the Lake 

Elbert and Long Lake Reservoir watersheds are less sensitive to atmospheric deposition of nitrogen than reservoirs in 

the Front Range of Colorado because of a greater capacity for 

nitrogen assimilation. Unfiltered total phosphorus concentrations in water samples from both water bodies were 0.02 mg/L 

or less. Water-supply standards for dissolved manganese and 

dissolved iron were exceeded on one and two sample days, 

respectively, for Long Lake Reservoir.

Depth-profile measurements for July 26, 2006, for one 

site near the dam in Stagecoach Reservoir and one site in 

Steamboat Lake were compiled for specific conductance, pH, 

water temperature, and dissolved oxygen (figs. 14A, 14B). 

Samples also were collected near the water surface and near 

the bottom of the water column for analysis of other physical 

properties, major ions, nutrients, trace elements, and chlorophyll a. Values for selected physical properties and constituents in the near surface and near bottom samples are shown in 

table 18.

Figure 13. Streamflow and concentrations of suspended 

sediment and unfiltered total phosphorus in Elkhead Creek above 

Long Gulch (site 40), Upper Yampa River watershed, Colorado, 

July 1995 through September 2003.

0.01

0.1

1

10

100

1,000

10,000

Concentrations of suspended sediment

and unfiltered total phosphorus,

in milligrams per liter

Year

Streamflow

Suspended sediment

Unfiltered total phosphorus

EXPLANATION

Streamflow,

in cubic feet per second

1995

0.01

0.1

10

100

1,000

10,000

1

1996

1997

19981999

2000

2001

2002

2003

2004
58 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Table 16. Summary statistics for suspended-sediment water-quality data for stream sampling sites in the Upper Yampa River 

watershed and subwatersheds, Colorado, 1975 through 2003.

[No., number. All suspended-sediment values are reported in milligrams per liter. Number of significant figures for suspended-sediment data may vary because 

data are from different sources and analytical periods.]

Watershed or subwatershed No. of

sites

No. of

samples

No. of

censored 

values1

Minimum 

value

Median 

value

Maximum

value

Upper Yampa River watershed 65 1,079 11 0 40 11,300

Subwatershed

Yampa River and tributaries upstream from Chuck Lewis State 

Wildlife Area (Yampa River subwatershed 1)

17 261 0 0 33 2,340

Yampa River and tributaries from Chuck Lewis State Wildlife 

Area to Elk River confluence (Yampa River subwatershed 2)

14 66 0 0 7 676

Elk River and tributaries (Elk River subwatershed) 10 101 11 0 4 565

Yampa River and tributaries from Elk River confluence to 

Town of Hayden (Yampa River subwatershed 3)

12 399 0 0 85 11,300

Yampa River and tributaries from Town of Hayden to Elkhead 

Creek confluence (Yampa River subwatershed 4)

5 92 0 8.3 90 10,200

Elkhead Creek and tributaries (Elkhead Creek subwatershed) 7 160 0 1 16 2,197 1

Censored values can be expressed as values less than the laboratory reporting level.

Table 17. Summary statistics for selected water-quality data and Colorado Department of Public Health and Environment in-stream 

water-quality standards for sampling sites in Lake Elbert and Long Lake Reservoir, Upper Yampa River watershed, Colorado.

[No., number; μS/cm; microsiemens per centimeter at 25 degrees Celsius; --, no water-quality standard; mg/L, milligrams per liter; nd, not determined; CaCO3, 

calcium carbonate; WS, water supply; N, nitrogen; <, less than; nc, not computed; P, phosphorus; μg/L, micrograms per liter; TVS, table value standard. 

Samples from Lake Elbert were collected from 1985 through 2009. Samples from Long Lake Reservoir were collected from 1985 through 2005. Summary 

statistics are calculated from samples collected near the water surface. Water-quality standards are from Colorado Department of Public Health and Environment 

(2009a, 2010); standards are for aquatic-life protection, unless otherwise stated. Descriptions of stream segments are in Colorado Department of Public Health 

and Environment (2010)]

Physical property 

or constituent 

(reporting units)

No. of 

sample 

days

No. of 

censored 

values1

Minimum 

value

Median 

value

Maximum 

value

In-stream

water-quality 

standard

No. of sample

days with data 

exceeding standard

Lake Elbert (stream segment 1b)

Specific conductance (μS/cm) 34 0 7.2 10.6 13.3 -- --

pH (standard units) 28 0 6.7 7.1 7.6 6.5–9.0 0

Dissolved oxygen (mg/L) 25 0 5.9 6.5 7.5 6.0 nd2

Hardness (mg/L as CaCO3) 71 0 2.6 3.4 5.1 -- --

Acid neutralizing capacity (mg/L as CaCO3) 29 0 2.6 3.5 4.4 -- --

Sulfate, dissolved (mg/L) 73 0 0.307 0.504 0.700 250 (WS) 0

Nitrate, dissolved (mg/L as N) 73 70 <0.006 nc 0.014 10 0

Total phosphorus, unfiltered (mg/L as P) 35 5 30.001 <0.005 0.02 -- --

Iron, dissolved (μg/L) 31 1 <3 20 98 300 (WS) 0

Iron, total recoverable (μg/L) 30 0 20 85 370 1,000 0

Manganese, dissolved (μg/L) 32 12 <1 1 4 TVS, 50 (WS) 0

Long Lake Reservoir (stream segment 2b)

Specific conductance, laboratory (μS/cm) 38 0 14.0 18.3 34.0 -- --

pH (standard units) 32 0 6.2 7.2 8.2 6.5–9.0 3

Dissolved oxygen (mg/L) 10 0 0.2 6.4 7.4 6.0 nd2

Hardness (mg/L as CaCO3) 63 0 5.4 7.5 15.8 -- --

Acid neutralizing capacity (mg/L as CaCO3) 39 0 2.1 6.1 17.9 -- --

Sulfate, dissolved (mg/L) 63 0 0.892 1.3 2.5 250 (WS) 0

Nitrate, dissolved (mg/L as N) 63 53 <0.007 nc 0.11 10 0

Total phosphorus, unfiltered (mg/L as P) 2 0 0.017 0.018 0.02 -- --

Iron, dissolved (μg/L) 42 0 44 140 400 300 (WS) 2 (WS)

Manganese, dissolved (μg/L) 42 3 <1 4 150 TVS, 50 (WS) 1 (WS) 1

Censored values can be expressed as values less than the laboratory reporting level.

2

The number of exceedances of the water-quality standard could not be determined. Application of the dissolved oxygen standard is dependent on depth 

of water. Sample depth was not recorded for most samples with dissolved oxygen data.

3

The minimum censored value is greater than the minimum detected value. 
Water-Quality Assessment 59 Figure 14. Depth profiles of specific conductance, pH, water temperature, and dissolved oxygen concentrations for (A) Stagecoach Reservoir and (B) Steamboat Lake, Upper Yampa River watershed, Colorado, July 25, 2006. 7 8 9 10 8070

605040302010

Specific conductance,

in microsiemens per

centimeter at 25 degrees Celsius

pH,

in standard units

68 70 72 74

807060504030201

00

0

Depth below water surface,

in feet

B

7 8 9 10

120100

80604020

350 400 450 500

120

100

8060402

00

Depth below water surface,

in feet

A

0

120100

80604020

Stagecoach Reservoir

0 0

6 12 18 24 0 2 4 6 8 10 12 14

120100

8060402

0

0

0 6 12 18 24

8070605040302010

0 2 4 6 8 10 12 14

8070605040302010

Water temperature,

in degress Celsius

Concentration of dissolved oxygen,

in milligrams per liter

Steamboat Lake

0 0
60 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Vertical stratification within the water column was 

evident for specific conductance, pH, water temperature, and 

dissolved oxygen (fig. 14). Specific conductance was much 

higher for Stagecoach Reservoir than for Steamboat Lake. 

Most of the watershed for Stagecoach Reservoir overlies 

sedimentary rocks, which contribute dissolved materials to 

surface water (fig. 5). The watershed for Steamboat Lake 

primarily overlies igneous and metamorphic rocks that are 

more resistant to weathering and dissolution (fig. 5). Water 

clarity, as measured by Secchi depth transparency (Wetzel, 

1983), was lower in Stagecoach Reservoir (4.4 ft) than in 

Steamboat Lake (7.9 ft). This is probably due to an increased 

amount of particulate matter in Stagecoach Reservoir as 

compared to Steamboat Lake. Water column pH was lower 

(about 7.2–7.5) in Steamboat Lake than in Stagecoach Reservoir (7.9–9.1) (fig. 14). No exceedances of the CDPHE 

water-quality standard for pH of 6.5–9.0 were observed. Water 

temperature at the site near the dam in each reservoir was 

similar at the surface (about 22 °C) and lower (less than 6 °C) 

at depth in Stagecoach Reservoir than in Steamboat Lake (8.4 

°C or greater) (fig. 14). Anoxic conditions (dissolved oxygen 

concentrations less than 0.5 mg/L) at depth were indicated for 

both bodies of water (fig. 14). Loss of oxygen primarily is due 

to oxygen consumption at the sediment-water interface where 

bacterial decomposition of sediment organic matter is greatest and to the use of oxygen by aquatic organisms in the water 

column (Wetzel, 1983).

Concentrations of chemical constituents in both bodies of 

water were lower near the water surface than near the bottom 

of the water column (table 18). Concentrations of unfiltered 

nitrate less than detection levels in near-surface samples 

probably indicate biological uptake of the nutrient. Hardness, 

ANC, unfiltered sulfate, and total phosphorus in near-surface 

and near-bottom samples were higher in Stagecoach Reservoir, 

probably because of sedimentary rocks in the reservoir drainage basin. Concentrations of dissolved and total recoverable 

iron were higher in Steamboat Lake than in Stagecoach Reservoir, which could be attributed to the hydrologic interactions 

of water with igneous and metamorphic rocks in the reservoir 

drainage basin. Chlorophyll a was an order of magnitude 

higher in Stagecoach Reservoir than in Steamboat Lake. With 

only one sample, it is not possible to explain this difference in 

chlorophyll a concentration.

The quality of water in Elkhead Reservoir was studied by 

Kuhn and others (2003) from July 1995 through August 2001. 

Information presented in this paragraph on the water quality of the reservoir is from Kuhn and others (2003). Results 

from the study indicate seasonal changes in water quality for 

many physical properties and chemical constituents. Depthprofile measurements showed that the reservoir was stratified 

during summer and late winter and mixed during spring and 

fall. Minimum values of specific conductance (138 to 169 

μS/cm) occurred during snowmelt inflow, and maximum 

values (424 to 610 μS/cm) occurred during early spring prior 

to snowmelt runoff. Values of pH indicate neutral to slightly 

alkaline conditions. Median pH near the water surface ranged 

from 7.2 to 8.0. Water temperature was lowest (about 0 °C) 

during winter and warmest (about 20 °C) during summer. 

During stratification, median dissolved oxygen concentrations were about 7.1 and 7.2 for samples from near the water 

surface and 4.8 to 5.6 mg/L for near-bottom samples. Some 

concentrations in near-bottom samples were less than 0.5 

Table 18. Concentrations of selected physical properties and constituents in near-surface and near-bottom water-quality samples, 

Stagecoach Reservoir and Steamboat Lake, Upper Yampa River watershed, Colorado, July 25, 2006.

[mg/L, milligrams per liter; CaCO3, calcium carbonate; <, less than; N, nitrogen; P, phosphorus; μg/L micrograms per liter]

Physical property or constituent

(reporting units)

Stagecoach Reservoir Steamboat Lake

Sample depth

(feet) Value Sample depth(feet) Value

Hardness (mg/L as CaCO3) 0 170 3 29

104 200 68 30

Acid neutralizing capacity (mg/L as CaCO3) 0 150 3 34

104 180 68 35

Sulfate, unfiltered (mg/L) 0 46 3 <3

104 62 68 4

Nitrate, unfiltered (mg/L as N) 0 <0.02 3 <0.02

104 0.35 68 0.08

Total phosphorus, unfiltered (mg/L as P) 0 0.04 3 0.02

104 0.14 68 0.09

Iron, dissolved (μg/L) 0 <10 3 140

104 17 68 540

Iron, total recoverable (μg/L) 0 28 3 230

104 37 68 810

Manganese, dissolved (μg/L) 0 <2 3 2

104 160 68 110

Selenium, dissolved (μg/L) 0 <1 3 <1

104 1.1 68 <1

Chlorophyll a (μg/L) 0 8,200 3 800
Water-Quality Assessment 61

mg/L and indicate anoxic conditions. Water transparency was 

greatest after snowmelt because of the settling of suspended 

sediment. Concentrations of most nutrients in near-surface 

and near-bottom samples were highest during snowmelt 

inflow. Total phosphorus concentrations were highest at 

depth during July and September. Median concentrations of 

chlorophyll a were 1.1 μg/L or less at all sites. The trophic 

state of the reservoir ranged from oligotrophic (nutrient poor) 

to eutrophic (nutrient rich). Concentrations of nitrogen and 

phosphorous in 52 percent of samples indicate that phosphorus was the limiting nutrient; concentrations in 9 percent of 

samples indicate that nitrogen was the limiting nutrient. Fish 

consumption advisories for mercury have been established for 

Elkhead Reservoir and Lake Catamount, south of Steamboat 

Springs (http://www.cdphe.state.co.us/wq/FishCon/, accessed 

June 2012) (table 5).

Groundwater

Water-quality data for groundwater in the UYRW were 

available for 328 wells (table 3). Six wells were sampled by the 

CDOA during 1998, and 322 wells were sampled by the USGS 

from 1975 through 1989 (fig. 15, table 3, appendix 5). The sampled wells are concentrated in the middle latitudes of the watershed. About 39 percent (128 of 328) of the wells were located in 

the Yampa coal field (fig. 15). A total of 1,580 samples were collected—6 by the CDOA and 1,574 by the USGS. For the USGS 

wells, 810 samples had water-quality data and 764 samples had 

data only for water-level measurements. About 59 percent (479 

of 816) of the water-quality samples were collected from wells 

located in the Yampa coal field. Each CDOA well and about 

66 percent (212 of 322) of the USGS wells with water-quality 

data were sampled once. Samples with water-quality data most 

often were collected during 1975, 1978, and 1988 (table 19). 

All water-quality samples for groundwater, with the exception 

of one, had data for physical properties. The fewest data were 

available for organic carbon, stable isotopes (carbon, hydrogen, 

oxygen, sulfur), and radiochemical constituents (potassium-40, 

tritium) (table 19). Analysis of groundwater-quality data for 

this study focuses on one sample per day for physical properties, dissolved solids, major ions, nutrients, and trace elements. 

Multiple water-quality samples collected on the same day at a 

site are not included in the analysis.

For all CDOA wells and about 30 percent (97 of 322) of 

the USGS wells, no aquifer or geologic unit information was 

provided with the well-construction information. In this report, 

these wells are grouped in the category “unknown geologic 

units” (table 20). Wells with a geologic unit description tap 

aquifers in 12 geologic units, most commonly the flood-plain 

alluvium and Mesaverde Group (table 20). Water-quality samples most often were collected from aquifers in the unknown 

geologic units, Mesaverde Group, and terrace alluvium. Most 

(88 percent or more) of the samples collected from the unknown 

geologic units and the Mesaverde Group were from wells 

located in the Yampa coal field (table 20). The oldest geologic 

units with water-quality data presented in this report are the 

Precambrian erathem and the Jurassic Curtis Formation of the 

San Rafael Group. In ascending order, the stratigraphy of the 

Upper Cretaceous- and Tertiary-age formations with waterquality data are the Mancos Shale, Mesaverde Group (Iles and 

William Fork Formations), Lewis Shale, Fort Union Formation, and Browns Park Formation. The Upper Cretaceous and 

Eocene series represents rocks from particular time periods, 

but no information on individual geologic units is available 

from the aquifer descriptions. The Mancos Shale predominately is mudrock that formed in the marine environment of the 

Western Interior Seaway (Hettinger and Kirschbaum, 2002). 

It grades into the Mesaverde Group which consists of marine 

and nonmarine deposits of sandstone, shale, and coal beds that 

formed with the regression and transgression of the Western 

Interior Seaway (Brownfield and others, 1999). The Lewis 

Shale is composed of shale, siltstone, and smaller amounts of 

sandstone that formed in an offshore marine environment. The 

Tertiary Fort Union Formation is composed of sandstones, 

conglomerates, shales, and coal (Colson, 1969). The Browns 

Park Formation includes riverine sandstone, conglomerates, 

and siltstone that eroded from nearby mountains and volcanic 

ash (Covay and Tobin, 1981). Flood-plain and terrace alluvium 

and valley fill are Quaternary unconsolidated deposits of gravel, 

sand, silt, and clay along streams and in valleys and are derived 

from rock and soil erosion.

The quality of groundwater is a function of various physical and geochemical processes, including precipitation, the 

depositional environment and type of aquifer sediments that 

groundwater moves through, groundwater age, dissolution of 

soluble minerals in rocks and soils, ion exchange reactions, 

and reduction-oxidation processes. Reports with information 

on groundwater quality in the UYRW include Brodgen and 

Giles (1977), Covay and Tobin (1981), Robson and Stewart 

(1990), and Topper and others (2003). Additional reports are 

listed in Driver and others (1984).

Physical Properties

Data for physical properties of groundwater were available for 815 water-quality samples collected from 328 wells 

(table 19). Water temperature and specific conductance data 

were the most common, and dissolved oxygen concentrations were the least common (table 21). Specific conductance ranged from 50 to 15,900 μS/cm with a median of 

1,170 μS/cm (table 21). Median specific conductance was 

lowest (163 μS/cm) in samples from the Precambrian erathem, 

a geologic unit with igneous and metamorphic rocks (fig. 5, 

table 21). Specific conductance also typically was lower in 

samples from the Browns Park Formation than from the Lewis 

and Mancos Shales and Mesaverde Group (fig. 16), probably 

reflecting the riverine depositional environment of the Browns 

Park Formation and the marine or marine-nonmarine depositional environment of the latter three geologic units. Values of 

pH in UYRW groundwater samples ranged from 5.3 to 12.3, 

and the median was 7.6. About 14 percent (94 of 676) of pH 
62 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Figure 15. Location of groundwater wells completed in selected geologic units, Upper Yampa River watershed, Colorado, 1975 

through 1989 and 1998.

Fish Creek

Bear River

Grassy Creek

Dry Creek

YampaRiver

Elkhead Cr Elkhead Cr

First Cree k

Wolf Cr

Mad Creek

Oak Cr eek

Trout Creek

Ch mi ney Creek

Walton Creek

Foidel Creek

Elk River Elk River

Yampa River

Yampa River

Lost Dog Cr

Fish Creek

L

Service Creek

ittle Morrison Cr

BushyCreek

Morrison Cre ek

Sage Creek

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Reservoir

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187 186

185 182 184 183

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286 285 279 273

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369

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368 370

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AREA B

AREA C

AREA A

AREA D

Enlargement 

of AREA A

Enlargement

of AREA B

Enlargement

of AREA D

Enlargement

of AREA C

0 5 10 MILES

0 5 10 KILOMETERS

EXPLANATION

(! Unknown geologic units !( Alluvium, terrace !( Alluvium, flood plain

!( Valley-fill deposits !( Browns Park Formation !( Fort Union Formation

!( Eocene series

!( Upper Cretaceous series (! Lewis Shale

(! Mesaverde Group (! Mancos Shale

(! Curtis Formation of 

 San Rafael Group

(! Precambrian erathem

Geologic unit with aquifers that wells tap and site number

 (appendix 5)

107°00'

106°45'

107°15'

40°45'

40°30'

40°15'

40°00'

Yampa

coal field

Yampa

coal field

Yampa

coal field

Active coal

mining area

Steamboat

Springs
Water-Quality Assessment 63

Table 19. Period of water-quality record and number of water-quality samples collected per year from groundwater wells, by physical 

properties or constituent group, Upper Yampa River watershed Colorado, 1975 through 1989 and 1998.

[--, no data]

Physical properties

or constituent group

Number of water-quality samples collected

1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1998 Total

Upper Yampa River watershed

Physical properties 145 10 19 146 91 45 57 47 29 2 -- 3 22 1121 72 6 815

Dissolved solids 56 5 18 45 39 42 57 47 29 2 -- 3 22 1121 72 6 564

Major ions 56 5 18 45 61 43 57 47 29 2 -- 3 22 1121 72 6 587

Nutrients 56 5 18 45 35 43 55 47 29 -- -- 3 22 1120 10 6 494

Trace elements 56 5 18 46 84 43 57 47 29 2 -- 3 22 1121 72 4 609

Radiochemical -- -- -- -- -- 9 35 18 -- -- -- -- -- 22 4 -- 88

Organic carbon -- -- -- -- 1 -- 1 -- -- -- -- -- -- -- 4 -- 6

Stable isotopes -- -- -- -- -- -- -- -- -- -- -- -- -- 23 4 -- 27

Total number of samples 145 10 19 147 91 45 57 47 29 2 -- 3 22 1121 72 6 1

Count does not include multiple (14) samples collected on one day from selected wells.

Table 20. Number of wells sampled and groundwater-quality samples collected from selected geologic units in the Upper Yampa River 

watershed, Colorado, 1975 through 1989 and 1998.

[No., number; --, no data]

Geologic unit near 

well screen Geologic time Primary lithology No. of wells No. of groundwaterquality samples1

Alluvium, flood plain Quaternary Unconsolidated material 75 85

Alluvium, terrace Quaternary Unconsolidated material 23 122

Browns Park Formation Tertiary Sandstone 29 29

Curtis Formation of San Rafael Group Jurassic Sandstone, shale 1 1

Eocene series Tertiary Shale, sandstone 1 2

Fort Union Formation Tertiary Sandstone, shale, coal 1 1

Lewis Shale Cretaceous Shale, sandstone 14 19

Mancos Shale Cretaceous Shale, sandstone 23 26

Mesaverde Group Cretaceous Sandstone, shale, coal 46 142

Precambrian erathem Precambrian Crystalline rocks 2 2

Upper Cretaceous series Cretaceous Sandstone, shale, coal 3 3

Valley-fill deposits Quaternary Unconsolidated material 7 10

Unknown -- -- 103 374

Total number of wells and groundwater-quality samples 328 816 1

Count does not include multiple (14) water-quality samples collected on one day from selected wells.

values did not meet the CDPHE SMCL (table 21) (Colorado 

Department of Public Health and Environment, 2009b). Values 

less than the standard minima of 6.5 were not as common as 

values greater than the standard maxima of 8.5 (table 21). 

Values less than the standard minima were measured in 

14 samples from 13 wells, most commonly in 14 percent of 

samples from the flood-plain alluvium and 14 percent of wells 

completed in the valley-fill deposits. Values of pH greater than 

standard maxima were measured in 80 samples from 38 wells, 

most commonly in 16 percent of samples from unknown 

geologic units and 29 percent of wells from the Mesaverde 

Group. Less than 4 percent of wells in the Yampa coal field 

had sample pH less than 6.5. About 80 percent of all wells 

with sample pH greater than 8.5 were in the Yampa coal field. 

Water temperature ranged from 2 to 50 °C with a median of 

10.5 °C (table 21). Dissolved oxygen data were available for 

116 samples from 33 wells, and concentrations ranged from 0 

to 10 mg/L (table 21). High values of ANC in some samples 

from the sedimentary rock units indicate that the sample water 

was well buffered.

Reduction-oxidation (redox) processes can be an 

extremely valuable tool in interpreting water-quality data and 

assessing the susceptibility or vulnerability of an aquifer to 

contamination. Redox processes, including dissolved oxygen 

reduction and nitrate, iron, manganese, and sulfate reduction, 

affect water chemistry and water quality in all groundwater 

systems. Groundwater with dissolved oxygen concentrations 

greater than or equal to 0.5 mg/L (oxic conditions) can be 

more susceptible to nitrate contamination than other groundwater. Groundwater with dissolved oxygen concentrations 
64 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009 Table 21. Summary statistics for selected physical property water-quality data and exceedances of Colorado Department of Public Health and Environment water-quality standards for groundwater in the Upper Yampa River watershed, Colorado, 1975 through 1989 and 1998.—Continued [No., number; Min., minimum; Max., maximum; μS/cm, microsiemens per centimeter at 25 degrees Celsius; --, no water-quality standard; SMCL, secondary maximum contaminant level; °C, degrees Celsius; mg/L, milligrams per liter; CaCO3, calcium carbonate; ne, no exceedance. Number of significant figures for individual constituents may vary among the geologic units because data are from different sources and different analytical periods. Water-quality standards are from Colorado Department of Public Health and Environment (2009b] Physical property (reporting units) Total no. of wells Total no. of samples Total no. of censored values Min. value Median value Max. value Water-quality standard Exceedances of water-quality standard No. of wells No. of samples Year(s) Range of values not meeting standard Upper Yampa River watershed Specific conductance (μS/cm) 264 715 0 50 1,170 15,900 -- -- -- -- -- pH (standard units) 257 676 0 5.3 7.6 12.3 6.5 minima (SMCL) 13 14 11975–84 5.3–6.4 8.5 maxima (SMCL) 38 80 11975–89 8.6–12.3 Water temperature (°C) 327 731 0 2 10.5 50 -- -- -- -- -- Dissolved oxygen (mg/L) 33 116 0 0 1.4 10 -- -- -- -- -- Hardness (mg/L as CaCO3

) 201 574 0 4.9 330 7,000 -- -- -- -- --

Acid neutralizing capacity (mg/L as CaCO3

) 165 264 0 19 260 2,760 -- -- -- -- --

Alluvium, flood plain

Specific conductance (μS/cm) 43 45 0 77 370 1,850 -- -- -- -- --pH (standard units) 40 42 0 5.8 7.2 9.4 6.5 minima (SMCL) 5 6 1978 5.8–6.4

8.5 maxima (SMCL) 6 6 1978 8.7–9.4

Water temperature (°C) 75 84 0 4 11 30 -- -- -- -- --Dissolved oxygen (mg/L) 1 1 0 4.6 4.6 4.6 -- -- -- -- --Hardness (mg/L as CaCO3

) 15 16 0 19 170 550 -- -- -- -- --

Acid neutralizing capacity (mg/L as CaCO3

) 14 15 0 19 191 522 -- -- -- -- --

Alluvium, terrace

Specific conductance (μS/cm) 23 121 0 50 974 2,700 -- -- -- -- --pH (standard units) 23 88 0 7.0 7.6 8.5 6.5 minima (SMCL) 0 0 ne ne

8.5 maxima (SMCL) 0 0 ne ne

Water temperature (°C) 23 84 0 3 11 22 -- -- -- -- --Hardness (mg/L as CaCO3

) 22 43 0 140 440 1,100 -- -- -- -- --

Acid neutralizing capacity (mg/L as CaCO3

) 22 87 0 110 180 580 -- -- -- -- --

Browns Park Formation

Specific conductance (μS/cm) 28 28 0 50 455 1,475 -- -- -- -- --pH (standard units) 27 27 0 6.4 7.5 9.2 6.5 minima (SMCL) 1 1 1978 6.4

8.5 maxima (SMCL) 1 1 1978 9.2

Water temperature (°C) 28 28 0 5 9 22 -- -- -- -- --Hardness (mg/L as CaCO3

) 14 14 0 10 180 428 -- -- -- -- --

Acid neutralizing capacity (mg/L as CaCO3

) 7 7 0 150 210 700 -- -- -- -- --

Curtis Formation of San Rafael Group

Specific conductance (μS/cm) 1 1 0 430 430 430 -- -- -- -- --pH (standard units) 1 1 0 7.3 7.3 7.3 6.5 minima (SMCL) 0 0 ne ne

8.5 maxima (SMCL) 0 0 ne ne

Water temperature (°C) 1 1 0 38 38 38 -- -- -- -- --Hardness (mg/L as CaCO3

) 1 1 0 180 180 180 -- -- -- -- --

Acid neutralizing capacity (mg/L as CaCO3

) 1 1 0 210 210 210 -- -- -- -- --
Water-Quality Assessment 65

Table 21. Summary statistics for selected physical property water-quality data and exceedances of Colorado Department of Public Health and Environment water-quality standards for groundwater in the Upper Yampa River watershed, Colorado, 1975 through 1989 and 1998.—Continued[No., number; Min., minimum; Max., maximum; μS/cm, microsiemens per centimeter at 25 degrees Celsius; --, no water-quality standard; SMCL, secondary maximum contaminant level; °C, degrees Celsius; mg/L, milligrams per liter; CaCO3, calcium carbonate; ne, no exceedance. Number of significant figures for individual constituents may vary among the geologic units because data are from different sources and different analytical periods. Water-quality standards are from Colorado Department of Public Health and Environment (2009b]

Physical property

(reporting units)

Total no.

of wells

Total

no. of

samples

Total no. of

censored

values

Min.

value

Median

value

Max.

value

Water-quality

standard

Exceedances of water-quality standard

No. of

wells

No. of

samples Year(s)

Range of values 

not meeting

standard

Eocene series

Specific conductance (μS/cm) 1 1 0 800 800 800 -- -- -- -- --pH (standard units) 1 1 0 8.3 8.3 8.3 6.5 minima (SMCL) 0 0 ne ne

8.5 maxima (SMCL) 0 0 ne ne

Water temperature (°C) 1 2 0 16 16 16 -- -- -- -- --Hardness (mg/L as CaCO3

) 1 1 0 12 12 12 -- -- -- -- --

Acid neutralizing capacity (mg/L as CaCO3

) 1 1 0 366 366 366 -- -- -- -- --

Fort Union Formation

Specific conductance (μS/cm) 1 1 0 1,125 1,125 1,125 -- -- -- -- --pH (standard units) 1 1 0 6.5 6.5 6.5 6.5 minima (SMCL) 0 0 ne ne

8.5 maxima (SMCL) 0 0 ne ne

Water temperature (°C) 1 1 0 14 14 14 -- -- -- -- --Hardness (mg/L as CaCO3

) 1 1 0 390 390 390 -- -- -- -- --

Acid neutralizing capacity (mg/L as CaCO3

) 1 1 0 75 75 75 -- -- -- -- --

Lewis Shale

Specific conductance (μS/cm) 9 11 0 470 1,200 4,000 -- -- -- -- --pH (standard units) 9 11` 0 6.9 8.0 9.0 6.5 minima (SMCL) 0 0 ne ne

8.5 maxima (SMCL) 1 1 1978 9.0

Water temperature (°C) 14 19 0 9 12 21 -- -- -- -- --Hardness (mg/L as CaCO3

) 6 6 0 24 370 630 -- -- -- -- --

Acid neutralizing capacity (mg/L as CaCO3

) 6 7 0 189 255 1,190 -- -- -- -- --

Mancos Shale

Specific conductance (μS/cm) 23 25 0 75 766 3,800 -- -- -- -- --pH (standard units) 23 24 0 6.1 7.4 8.7 6.5 minima (SMCL) 1 1 1978 6.1

8.5 maxima (SMCL) 1 1 1975 8.7

Water temperature (°C) 21 24 0 5 10 15 -- -- -- -- --Hardness (mg/L as CaCO3

) 13 14 0 10 225 1,800 -- -- -- -- --

Acid neutralizing capacity (mg/L as CaCO3

) 12 13 0 82 340 1,800 -- -- -- -- --

Mesaverde Group

Specific conductance (μS/cm) 45 133 0 225 1,390 6,000 -- -- -- -- --pH (standard units) 42 129 0 5.3 7.4 11.5 6.5 minima (SMCL) 5 5 11977–84 5.3–6.4

8.5 maxima (SMCL) 12 17 11977–83 8.6–11.5

Water temperature (°C) 45 138 0 3 10 50 -- -- -- -- --Dissolved oxygen (mg/L) 46 57 0 0.0 1.6 10.0 -- -- -- -- --Hardness (mg/L as CaCO3

) 40 128 0 6 450 3,250 -- -- -- -- --

Acid neutralizing capacity (mg/L as CaCO3

) 39 54 0 74 430 2,760 -- -- -- -- --
66 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009 Table 21. Summary statistics for selected physical property water-quality data and exceedances of Colorado Department of Public Health and Environment water-quality standards for groundwater in the Upper Yampa River watershed, Colorado, 1975 through 1989 and 1998.—Continued [No., number; Min., minimum; Max., maximum; μS/cm, microsiemens per centimeter at 25 degrees Celsius; --, no water-quality standard; SMCL, secondary maximum contaminant level; °C, degrees Celsius; mg/L, milligrams per liter; CaCO3, calcium carbonate; ne, no exceedance. Number of significant figures for individual constituents may vary among the geologic units because data are from different sources and different analytical periods. Water-quality standards are from Colorado Department of Public Health and Environment (2009b] Physical property (reporting units) Total no. of wells Total no. of samples Total no. of censored values Min. value Median value Max. value Water-quality standard Exceedances of water-quality standard No. of wells No. of samples Year(s) Range of values not meeting standard Precambrian erathem Specific conductance (μS/cm) 2 2 0 103 163 223 -- -- -- -- -- pH (standard units) 2 2 0 7.1 7.6 8.0 6.5 minima (SMCL) 0 0 ne ne 8.5 maxima (SMCL) 0 0 ne ne Water temperature (°C) 2 2 0 5 6 7 -- -- -- -- -- Hardness (mg/L as CaCO3

) 1 1 0 40 40 40 -- -- -- -- --

Acid neutralizing capacity (mg/L as CaCO3

) 1 1 0 49 49 49 -- -- -- -- --

Upper Cretaceous series

Specific conductance (μS/cm) 3 3 0 880 890 6,000 -- -- -- -- --pH (standard units) 3 3 0 7.3 7.4 8.1 6.5 minima (SMCL) 0 0 ne ne

8.5 maxima (SMCL) 0 0 ne ne

Water temperature (°C) 3 3 0 9 12 13.5 -- -- -- -- --Hardness (mg/L as CaCO3

) 2 2 0 25 188 350 -- -- -- -- --

Acid neutralizing capacity (mg/L as CaCO3

) 1 1 0 378 378 378 -- -- -- -- --

Valley-fill deposits

Specific conductance (μS/cm) 7 8 0 135 380 1,450 -- -- -- -- --pH (standard units) 7 8 0 6.1 7.1 7.5 6.5 minima (SMCL) 1 1 1975 6.1

8.5 maxima (SMCL) 0 0 ne ne

Water temperature (°C) 7 10 0 9 13 20 -- -- -- -- --Hardness (mg/L as CaCO3

) 7 7 0 58 170 820 -- -- -- -- --

Acid neutralizing capacity (mg/L as CaCO3

) 7 7 0 61 122 475 -- -- -- -- --

Unknown geologic units

Specific conductance (μS/cm) 78 336 0 122 1,325 15,900 -- -- -- -- --pH (standard units) 78 332 0 6.6 7.8 12.3 6.5 minima (SMCL) 0 0 ne ne

8.5 maxima (SMCL) 17 54 11975–89 8.6–12.3

Water temperature (°C) 103 339 0 2 10 37 -- -- -- -- --Dissolved oxygen (mg/L) 16 58 0 0.3 1.2 7.4 -- -- -- -- --Hardness (mg/L as CaCO3

) 78 339 0 4.87 300 7,000 -- -- -- -- --

Acid neutralizing capacity (mg/L as CaCO3

) 53 68 0 33 372 700 -- -- -- -- --

1Exceedances did not occur in every year of the period of record.
Water-Quality Assessment 67

less than 0.5 mg/L (anoxic, reducing conditions) can be more 

susceptible to contamination from sulfate, iron, manganese, 

and other water-quality constituents (Jurgens and others, 

2009). For the UYRW, there were insufficient data to relate 

concentrations of nitrate, arsenic, and other chemical constituents in groundwater to redox conditions. Less than 3 percent 

(23 of 816) of groundwater samples could be classified as 

oxic or anoxic using the redox framework devised by Jurgens 

and others (2009) to classify and assess redox conditions 

in groundwater.

Dissolved Solids and Majors Ions

Dissolved solids data were available for 564 groundwater 

samples collected from 191 wells (table 22). Concentrations 

ranged from 46 to 8,490 mg/L with a median of 812 mg/L. 

Among the geologic units with more than one sample, the 

median concentration was lowest (255 mg/L) for samples from 

the valley-fill deposits and highest (894 mg/L) for samples 

from the Mesaverde Group.

Major ion data were available for 559 groundwater 

samples collected from as many as 186 wells. A total of 

184 samples with data for the cations calcium, magnesium, 

sodium, and potassium and the anions bicarbonate, chloride, fluoride, and sulfate were used to calculate water type 

for geologic units with multiple samples. Calcium and (or) 

calcium plus magnesium or a mixture of these with sodium 

were the dominant cations (fig. 17). Sodium was more common in groundwater from the Mesaverde Group than the other 

major geologic units. Bicarbonate was the dominant anion, 

but many samples also had sulfate, particularly those from the 

terrace alluvium and the Mesaverde Group (fig. 17). Calcium 

and magnesium can come from the dissolution of calcite 

and dolomite from limey shales, limestones, and dolomitic 

limestones, and sodium can come from cation exchange reactions with calcium and magnesium ions (Robson and Stewart, 

1990). Dissolution of carbonate minerals is likely the source 

of bicarbonate; sulfate may occur because of the dissolution 

of gypsum and oxidation of the minerals pyrite and marcasite 

(Robson and Stewart, 1990). Insufficient leaching of materials 

in soil from the lack of precipitation in a semiarid climate may 

cause sulfate to remain near the land surface (Hem, 1992).

Dissolved sulfate concentrations ranged from less than 

1 to 4,000 mg/L with a median of 220 mg/L (table 22). For 

the geologic units with multiple samples, the median dissolved sulfate concentration was lowest (5.9 mg/L) for samples 

from the Browns Park Formation and highest (315 mg/L) for 

samples from the terrace alluvium. Concentrations in almost 

one-half (250 of 554) of the samples analyzed for dissolved 

sulfate were greater than the CDPHE SMCL of 250 mg/L for 

groundwater (table 22) (Colorado Department of Public Health 

and Environment, 2009b). Between about 47 and 57 percent of 

samples collected from the terrace alluvium, Mesaverde Group, 

and unknown geologic units had dissolved sulfate concentrations that did not meet the standard. Wells with concentrations 

exceeding the standards were commonly completed in unknown 

geologic units (mostly in the Yampa coal field) and terrace alluvium, about 54 and 64 percent of wells, respectively. All terrace 

alluvium wells were in one small area (Area A on fig. 15) in the 

UYRW downstream from Sage Creek.

The range in dissolved chloride concentrations of 0.5 

to 5,000 mg/L was similar to that for dissolved sulfate, but 

the median chloride concentration of 10 mg/L was much 

lower than that for sulfate (table 22). For the geologic units 

with more than one sample, median concentrations were 6.3 

mg/L or less from samples from the flood-plain alluvium, 

Browns Park Formation, and valley-fill deposits. Median 

Figure 16. Specific conductance in groundwater samples from selected geologic units in the Upper 

Yampa River watershed, Colorado, 1975 through 1986.

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

Specific conductance.

in microsiemens per centimeter 

at 25 degrees Celsius

Geologic unit

45 121 28 11 25 133

Percentiles

90th

75th

25th

50th

10th

EXPLANATION

Number of samples

Data values outside the

 10th and 90th percentiles

133

Flood-plain

alluvium

Terrace

alluvium

Browns

Park

Formation

Lewis

Shale

Mancos

Shale

Mesaverde

Group
68 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009 Table 22. Summary statistics for dissolved solids and selected major ion water-quality data and exceedances of Colorado Department of Public Health and Environment water- quality standards for groundwater in the Upper Yampa River watershed, Colorado, 1975 through 1989 and 1998.—Continued [No., number; Min., minimum; Max., maximum; --, no water-quality standard; <, less than; SMCL, secondary maximum contaminant level; MCL, maximum contaminant level; ne, no exceedance. All constituents are reported in milligrams per liter. Number of significant figures for individual constituents may vary among the geologic units because data are from different sources and different analytical periods. Water-quality standards are from Colorado Department of Public Health and Environment (2009b)] Constituent Total no. of wells Total no. of samples Total no. of censored values1 Min. value Median value Max. value Water- quality standard Exceedances of water-quality standard No. of wells No. of samples Year(s) Range of values not meeting standard Upper Yampa River watershed Dissolved solids 191 564 0 46 812 8,490 -- -- -- -- -- Calcium, dissolved 186 559 0 1.3 73 2,800 -- -- -- -- -- Magnesium, dissolved 186 559 2 <0.1 33 470 -- -- -- -- -- Sodium, dissolved 185 558 0 2.2 150 1,300 -- -- -- -- -- Potassium, dissolved 186 559 0 0.3 3.8 1,500 -- -- -- -- -- Bicarbonate, unfiltered 158 208 0 0 372 3,360 -- -- -- -- -- Sulfate, dissolved 185 554 1 <1 220 4,000 250 (SMCL) 71 250 21975–89 260–4,000 Chloride, dissolved 185 554 0 0.5 10 5,000 250 (SMCL) 8 15 1975–82 280–5,000 Fluoride, dissolved 184 557 0 0.1 0.4 15 4 (MCL) 4 5 21975–89 4.1–15 Silica, dissolved 184 557 1 30.3 11 150 -- -- -- -- -- Alluvium, flood plain Dissolved solids 14 15 0 46 289 1,140 -- -- -- -- -- Calcium, dissolved 14 15 0 5.6 47 80 -- -- -- -- -- Magnesium, dissolved 14 15 0 1.1 15 90 -- -- -- -- -- Sodium, dissolved 14 15 0 2.2 17 240 -- -- -- -- -- Potassium, dissolved 14 15 0 0.5 2.0 3.2 -- -- -- -- -- Bicarbonate, unfiltered 14 15 0 23 233 637 -- -- -- -- -- Sulfate, dissolved 14 15 0 3.8 49 370 250 (SMCL) 1 1 1975 370 Chloride, dissolved 14 15 0 1.8 6.3 61 250 (SMCL) 0 0 ne ne Fluoride, dissolved 14 15 0 0.1 0.3 2.3 4 (MCL) 0 0 ne ne Silica, dissolved 14 15 0 7.0 13 20 -- -- -- -- -- Alluvium, terrace Dissolved solids 22 44 0 205 733 2,110 -- -- -- -- -- Calcium, dissolved 22 44 0 31 96 270 -- -- -- -- -- Magnesium, dissolved 22 44 0 14 46 120 -- -- -- -- -- Sodium, dissolved 22 44 0 22 73 230 -- -- -- -- -- Potassium, dissolved 22 44 0 2.5 4.7 10 -- -- -- -- -- Bicarbonate, unfiltered 22 39 0 140 210 490 -- -- -- -- -- Sulfate, dissolved 22 44 0 42 315 1,200 250 (SMCL) 14 25 1978–79 280–1,200 Chloride, dissolved 22 44 0 8.7 42 200 250 (SMCL) 0 0 ne ne Fluoride, dissolved 22 44 0 0.2 0.7 1.2 4 (MCL) 0 0 ne ne Silica, dissolved 22 44 0 8.2 14 23 -- -- -- -- --
Water-Quality Assessment 69

Table 22. Summary statistics for dissolved solids and selected major ion water-quality data and exceedances of Colorado Department of Public Health and Environment waterquality standards for groundwater in the Upper Yampa River watershed, Colorado, 1975 through 1989 and 1998.—Continued[No., number; Min., minimum; Max., maximum; --, no water-quality standard; <, less than; SMCL, secondary maximum contaminant level; MCL, maximum contaminant level; ne, no exceedance. All constituents are reported in milligrams per liter. Number of significant figures for individual constituents may vary among the geologic units because data are from different sources and different analytical periods. Water-quality standards are from Colorado Department of Public Health and Environment (2009b)]

Constituent Total no. of wells Total no. of samples Total no. of censored values1 Min. value Median value Max. value Water- quality standard Exceedances of water-quality standard No. of wells No. of samples Year(s) Range of values not meeting standard

Browns Park Formation

Dissolved solids 7 7 0 203 329 813 -- -- -- -- --Calcium, dissolved 7 7 0 3.7 59 87 -- -- -- -- --Magnesium, dissolved 7 7 0 0.2 6.7 15 -- -- -- -- --Sodium, dissolved 7 7 0 6.3 13 340 -- -- -- -- --Potassium, dissolved 7 7 0 0.7 2.0 9.3 -- -- -- -- --Bicarbonate, unfiltered 7 7 0 180 250 720 -- -- -- -- --Sulfate, dissolved 7 7 0 4.6 5.9 110 250 (SMCL) 0 0 ne neChloride, dissolved 7 7 0 1.9 4.1 91 250 (SMCL) 0 0 ne neFluoride, dissolved 7 7 0 0.1 0.2 15 4 (MCL) 1 1 1978 15Silica, dissolved 7 7 0 10 18 60 -- -- -- -- --

Curtis Formation of San Rafael Group

Dissolved solids 1 1 0 263 263 263 -- -- -- -- --Calcium, dissolved 1 1 0 51 51 51 -- -- -- -- --Magnesium, dissolved 1 1 0 13 13 13 -- -- -- -- --Sodium, dissolved 1 1 0 27 27 27 -- -- -- -- --Potassium, dissolved 1 1 0 1.3 1.3 1.3 -- -- -- -- --Bicarbonate, unfiltered 1 1 0 260 260 260 -- -- -- -- --Sulfate, dissolved 1 1 0 23 23 23 250 (SMCL) 0 0 ne neChloride, dissolved 1 1 0 1.5 1.5 1.5 250 (SMCL) 0 0 ne neFluoride, dissolved 1 1 0 0.1 0.1 0.1 4 (MCL) 0 0 ne neSilica, dissolved 1 1 0 17 17 17 -- -- -- -- --

Eocene series

Dissolved solids 1 1 0 476 476 476 -- -- -- -- --Calcium, dissolved 1 1 0 3.8 3.8 3.8 -- -- -- -- --Magnesium, dissolved 1 1 0 0.6 0.6 0.6 -- -- -- -- --Sodium, dissolved 1 1 0 190 190 190 -- -- -- -- --Potassium, dissolved 1 1 0 1.3 1.3 1.3 -- -- -- -- --Bicarbonate, unfiltered 1 1 0 446 446 446 -- -- -- -- --Sulfate, dissolved 1 1 0 42 42 42 250 (SMCL) 0 0 ne neChloride, dissolved 1 1 0 7.3 7.3 7.3 250 (SMCL) 0 0 ne neFluoride, dissolved 1 1 0 2.7 2.7 2.7 4 (MCL) 0 0 ne neSilica, dissolved 1 1 0 8.4 8.4 8.4 -- -- -- -- --
70 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009 Table 22. Summary statistics for dissolved solids and selected major ion water-quality data and exceedances of Colorado Department of Public Health and Environment water- quality standards for groundwater in the Upper Yampa River watershed, Colorado, 1975 through 1989 and 1998.—Continued [No., number; Min., minimum; Max., maximum; --, no water-quality standard; <, less than; SMCL, secondary maximum contaminant level; MCL, maximum contaminant level; ne, no exceedance. All constituents are reported in milligrams per liter. Number of significant figures for individual constituents may vary among the geologic units because data are from different sources and different analytical periods. Water-quality standards are from Colorado Department of Public Health and Environment (2009b)] Constituent Total no. of wells Total no. of samples Total no. of censored values1 Min. value Median value Max. value Water- quality standard Exceedances of water-quality standard No. of wells No. of samples Year(s) Range of values not meeting standard Fort Union Formation Dissolved solids 1 1 0 717 717 717 -- -- -- -- -- Calcium, dissolved 1 1 0 100 100 100 -- -- -- -- -- Magnesium, dissolved 1 1 0 34 34 34 -- -- -- -- -- Sodium, dissolved 1 1 0 61 61 61 -- -- -- -- -- Potassium, dissolved 1 1 0 4.3 4.3 4.3 -- -- -- -- -- Bicarbonate, unfiltered 1 1 0 91 91 91 -- -- -- -- -- Sulfate, dissolved 1 1 0 180 180 180 250 (SMCL) 0 0 ne ne Chloride, dissolved 1 1 0 95 95 95 250 (SMCL) 0 0 ne ne Fluoride, dissolved 1 1 0 0.3 0.3 0.3 4 (MCL) 0 0 ne ne Silica, dissolved 1 1 0 32 32 32 -- -- -- -- -- Lewis Shale Dissolved solids 6 6 0 252 743 1,360 -- -- -- -- -- Calcium, dissolved 6 6 0 4.3 90 160 -- -- -- -- -- Magnesium, dissolved 6 6 0 3.1 35 67 -- -- -- -- -- Sodium, dissolved 5 5 0 13 63 570 -- -- -- -- -- Potassium, dissolved 6 6 0 0.8 2.0 4 -- -- -- -- -- Bicarbonate, unfiltered 5 5 0 230 311 1,450 -- -- -- -- -- Sulfate, dissolved 6 6 0 30 118 290 250 (SMCL) 1 1 1975 290 Chloride, dissolved 6 6 0 3.4 34 83 250 (SMCL) 0 0 ne ne Fluoride, dissolved 6 6 0 0.2 0.4 3 4 (MCL) 0 0 ne ne Silica, dissolved 6 6 0 8.8 12 22 -- -- -- -- -- Mancos Shale Dissolved solids 12 13 0 121 689 3,290 -- -- -- -- -- Calcium, dissolved 12 13 0 2.2 65 360 -- -- -- -- -- Magnesium, dissolved 12 13 0 1.2 24 210 -- -- -- -- -- Sodium, dissolved 12 13 0 5.6 94 1,000 -- -- -- -- -- Potassium, dissolved 12 13 0 1.1 2.6 5.6 -- -- -- -- -- Bicarbonate, unfiltered 12 13 0 100 415 2,200 -- -- -- -- -- Sulfate, dissolved 12 13 0 7.7 100 1,700 250 (SMCL) 2 2 1975, 1978 420, 1,700 Chloride, dissolved 12 13 0 1.8 12 350 250 (SMCL) 3 3 1975, 1978 300–350 Fluoride, dissolved 12 13 0 0.1 0.3 5.1 4 (MCL) 2 2 1975 4.8, 5.1 Silica, dissolved 12 13 0 6.3 13 150 -- -- -- -- --
Water-Quality Assessment 71

Table 22. Summary statistics for dissolved solids and selected major ion water-quality data and exceedances of Colorado Department of Public Health and Environment waterquality standards for groundwater in the Upper Yampa River watershed, Colorado, 1975 through 1989 and 1998.—Continued[No., number; Min., minimum; Max., maximum; --, no water-quality standard; <, less than; SMCL, secondary maximum contaminant level; MCL, maximum contaminant level; ne, no exceedance. All constituents are reported in milligrams per liter. Number of significant figures for individual constituents may vary among the geologic units because data are from different sources and different analytical periods. Water-quality standards are from Colorado Department of Public Health and Environment (2009b)]

Constituent Total no. of wells Total no. of samples Total no. of censored values1 Min. value Median value Max. value Water- quality standard Exceedances of water-quality standard No. of wells No. of samples Year(s) Range of values not meeting standard

Mesaverde Group

Dissolved solids 40 128 0 133 894 6,560 -- -- -- -- --Calcium, dissolved 41 129 0 1.8 89 960 -- -- -- -- --Magnesium, dissolved 41 129 2 <0.1 53 420 -- -- -- -- --Sodium, dissolved 41 129 0 3.7 190 930 -- -- -- -- --Potassium, dissolved 41 129 0 48 6.3 1,500 -- -- -- -- --Bicarbonate, unfiltered 39 55 0 90 518 3,360 -- -- -- -- --Sulfate, dissolved 41 126 0 1.2 260 2,900 250 (SMCL) 15 64 21975–86 260–2,900Chloride, dissolved 41 126 0 1.2 9.5 1,900 250 (SMCL) 2 3 21976–80 280-1,900Fluoride, dissolved 40 128 0 0.1 0.4 3.1 4 (MCL) 0 0 ne neSilica, dissolved 41 129 0 0.3 10 35 -- -- -- -- --

Precambrian erathem

Dissolved solids 1 1 0 64 64 64 -- -- -- -- --Calcium, dissolved 1 1 0 9.2 9.2 9.2 -- -- -- -- --Magnesium, dissolved 1 1 0 4.2 4.2 4.2 -- -- -- -- --Sodium, dissolved 1 1 0 3.2 3.2 3.2 -- -- -- -- --Potassium, dissolved 1 1 0 1.4 1.4 1.4 -- -- -- -- --Bicarbonate, unfiltered 1 1 0 60 60 60 -- -- -- -- --Sulfate, dissolved 1 1 0 2.7 2.7 2.7 250 (SMCL) 0 0 ne neChloride, dissolved 1 1 0 4.2 4.2 4.2 250 (SMCL) 0 0 ne neFluoride, dissolved 1 1 0 0.2 0.2 0.2 4 (MCL) 0 0 ne neSilica, dissolved 1 1 0 8.6 8.6 8.6 -- -- -- -- --

Upper Cretaceous series

Dissolved solids 1 1 0 569 569 569 -- -- -- -- --Calcium, dissolved 1 1 0 87 87 87 -- -- -- -- --Magnesium, dissolved 1 1 0 33 33 33 -- -- -- -- --Sodium, dissolved 1 1 0 70 70 70 -- -- -- -- --Potassium, dissolved 1 1 0 2.6 2.6 2.6 -- -- -- -- --Bicarbonate, unfiltered 1 1 0 461 461 461 -- -- -- -- --Sulfate, dissolved 1 1 0 110 110 110 250 (SMCL) 0 0 ne neChloride, dissolved 1 1 0 19 19 19 250 (SMCL) 0 0 ne neFluoride, dissolved 1 1 0 0.3 0.3 0.3 4 (MCL) 0 0 ne neSilica, dissolved 1 1 0 11 11 11 -- -- -- -- --
72 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009 Table 22. Summary statistics for dissolved solids and selected major ion water-quality data and exceedances of Colorado Department of Public Health and Environment water- quality standards for groundwater in the Upper Yampa River watershed, Colorado, 1975 through 1989 and 1998.—Continued [No., number; Min., minimum; Max., maximum; --, no water-quality standard; <, less than; SMCL, secondary maximum contaminant level; MCL, maximum contaminant level; ne, no exceedance. All constituents are reported in milligrams per liter. Number of significant figures for individual constituents may vary among the geologic units because data are from different sources and different analytical periods. Water-quality standards are from Colorado Department of Public Health and Environment (2009b)] Constituent Total no. of wells Total no. of samples Total no. of censored values1 Min. value Median value Max. value Water- quality standard Exceedances of water-quality standard No. of wells No. of samples Year(s) Range of values not meeting standard Valley-fill deposits Dissolved solids 7 7 0 82 255 1,050 -- -- -- -- -- Calcium, dissolved 7 7 0 16 49 200 -- -- -- -- -- Magnesium, dissolved 7 7 0 4.5 11 77 -- -- -- -- -- Sodium, dissolved 7 7 0 3.6 23 34 -- -- -- -- -- Potassium, dissolved 7 7 0 0.3 1.7 5 -- -- -- -- -- Bicarbonate, unfiltered 7 7 0 74 149 557 -- -- -- -- -- Sulfate, dissolved 7 7 0 1.7 34 420 250 (SMCL) 1 1 1975 420 Chloride, dissolved 7 7 0 0.5 4 21 250 (SMCL) 0 0 ne ne Fluoride, dissolved 7 7 0 0.1 0.2 0.7 4 (MCL) 0 0 ne ne Silica, dissolved 7 7 0 11 14 26 -- -- -- -- -- Unknown geologic units Dissolved solids 78 339 0 89 845 8,490 -- -- -- -- -- Calcium, dissolved 72 333 0 1.3 66 2,800 -- -- -- -- -- Magnesium, dissolved 72 333 0 0.3 26 470 -- -- -- -- -- Sodium, dissolved 72 333 0 9.9 160 1,300 -- -- -- -- -- Potassium, dissolved 72 333 0 0.8 3.4 170 -- -- -- -- -- Bicarbonate, unfiltered 47 62 0 0 470 732 -- -- -- -- -- Sulfate, dissolved 71 331 1 <1 240 4,000 250 (SMCL) 38 156 21975–89 260–4,000 Chloride, dissolved 72 331 0 1.4 9.1 5,000 250 (SMCL) 3 9 21975–82 350–5,000 Fluoride, dissolved 72 332 0 0.1 0.4 4.3 4 (MCL) 1 2 1988, 1989 4.1, 4.3 Silica, dissolved 70 331 1 3

1 10 38 -- -- -- -- -- 1Censored values can be expressed as values less than the laboratory reporting level.

2Exceedances did not occur in every year of the period of record.3The minimum censored value is greater than the minimum detected value that is shown. 
Water-Quality Assessment 73

concentrations of 12 and 34 mg/L in the Mancos and Lewis 

Shales, respectively, probably reflect the marine origin of the 

formations. Concentrations of dissolved chloride in about 

2.7 percent (15 of 554) of samples did not meet the CDPHE 

SMCL of 250 mg/L for groundwater (table 22) (Colorado 

Department of Public Health and Environment, 2009b). Most 

(9 of 15) exceedances were in samples from wells with no 

geologic unit description; three exceedances each were in 

samples from the Mancos Shale and Mesaverde Group.

Dissolved fluoride concentrations generally were much 

lower than concentrations for the other major ions studied. Concentrations of dissolved fluoride ranged from 0.1 to 15 mg/L, 

and the median was 0.4 mg/L (table 22). Five of 557 dissolved 

fluoride concentrations did not meet the CDPHE MCL of 

4 mg/L for groundwater (table 22) (Colorado Department of 

Public Health and Environment, 2009b).

Nutrients

Nutrient data were available for 494 groundwater 

samples (table 19) collected from 189 wells. Dissolved nitrate 

plus nitrite data were the most common (473 samples), and 

total unfiltered phosphorus data were the least common (42 

samples) (table 23). Data for dissolved nitrite only were 

available for wells in the Mesaverde Group and unknown 

geologic units. Most (112 of 142) dissolved nitrite concentrations were less than laboratory detection levels (table 23). All 

concentrations were 0.26 mg/L or less, well below the CDPHE 

MCL of 1 mg/L of nitrite in groundwater and the agriculturaluse standard for livestock watering of 10 mg/L (table 23) 

(Colorado Department of Public Health and Environment, 

2009b). Data for dissolved nitrate plus nitrite were most common for samples from wells with no geologic unit description 

Figure 17. Major cation and anion percentages and water type for groundwater samples from selected 

geologic units in the Upper Yampa River watershed, Colorado, 1975 through 1984.

0 20 40 60 80 100

Calcium + magnesium

PERCENT

Sulfate

Chloride + Fluoride

Percentage of milliequivalents per liter

Sodium + potassium

Bicarbonate

Magnesium

PERCENT

Chloride + Fluoride + Sulfate

EXPLANATION

Mancos Shale

Lewis Shale

Alluvium, terrace

Mesaverde Group

Alluvium, flood plain

Browns Park Formation

Calcium

PERCENT

100

100

100

80

80

80

60

60

60

100

80

60

40

20

0

40

40

40

20

20

20

0

0

0

100

80

60

40

20

80

80

60

60

40

40

20

20

0

0

100

100

0

100

80

60

40

20

0

100 80 60 40 20 0
74 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009 Table 23. Summary statistics for selected nutrient water-quality data and exceedances of Colorado Department of Public Health and Environment water-quality standards for groundwater in the Upper Yampa River watershed, Colorado, 1975 through 1989 and 1998.—Continued

[No., number; Min., minimum; Max., maximum; N, nitrogen; <, less than; MCL, maximum contaminant level; Ag, Agriculture; ne, no exceedance; E, estimated; --, no water-quality standard; P, phosphorus. All constituents are reported in milligrams per liter. Number of significant figures for individual constituents may vary among the geologic units because data are from different sources and different analytical periods. Water-quality standards are from Colorado Department of Public Health and Environment (2009b)]

Constituent Total no.

of wells

Total no.

of samples

Total no.

of censored

values1

Min.

value

Median

value

Max.

value

Waterquality 

standard

Exceedances of water-quality standard

Standard No. of wells No. of samples Year(s) Range of values not meeting standard

Upper Yampa River watershed

Nitrite, dissolved, as N 27 142 112 <0.01 <0.01 0.26 1 (MCL), 10 (Ag) ne 0 0 ne neNitrate plus nitrite, dissolved, as N 182 467 128 <0.01 E 0.11 37 10 (MCL)2, 100 (Ag) MCL 13 21 31975–89 12–37Total ammonia, dissolved, as N 29 144 0 0.03 0.45 5.6 -- -- -- -- -- --Total phosphorus, dissolved, as P 68 278 54 <0.01 0.02 0.76 -- -- -- -- -- --Total phosphorus, unfiltered, as P 42 42 10 <0.01 0.02 0.33 -- -- -- -- -- --Orthophosphate, dissolved, as P 180 375 134 <0.01 E 0.03 2.4 -- -- -- -- -- --

Alluvium, flood plain

Nitrate plus nitrite, dissolved, as N 14 15 0 0.01 0.81 18 10 (MCL)2, 100 (Ag) MCL 1 1 1976 18Total phosphorus, unfiltered, as P 8 8 3 <0.01 0.02 0.08 -- -- -- -- -- --Orthophosphate, dissolved, as P 14 15 5 <0.01 0.03 0.09 -- -- -- -- -- --

Alluvium, terrace

Nitrate plus nitrite, dissolved, as N 22 45 0 0.11 1.5 20 10 (MCL)2, 100 (Ag) MCL 1 3 1979 18, 20Total ammonia, dissolved, as N 1 1 0 1.3 1.3 1.3 -- -- -- -- -- --Total phosphorus, dissolved, as P 22 44 0 0.01 0.05 0.23 -- -- -- -- -- --Orthophosphate, dissolved, as P 22 26 7 <0.01 0.04 0.43 -- -- -- -- -- --

Browns Park Formation

Nitrate plus nitrite, dissolved, as N 7 7 0 0.04 0.34 13 10 (MCL)2, 100 (Ag) MCL 1 1 1978 13Orthophosphate, dissolved, as P 7 7 1 <0.01 0.03 0.31 -- -- -- -- --

Curtis Formation of San Rafael Group

Nitrate plus nitrite, dissolved, as N 1 1 0 0.13 0.13 0.13 10 (MCL)2, 100 (Ag) ne 0 0 ne neOrthophosphate, dissolved, as P 1 1 1 <0.01 <0.01 <0.01 -- -- -- -- -- --

Eocene series

Nitrate plus nitrite, dissolved, as N 1 1 0 0.02 0.02 0.02 10 (MCL)2, 100 (Ag) ne 0 0 ne neTotal phosphorus, unfiltered, as P 1 1 0 0.03 0.03 0.03 -- -- -- -- -- --Orthophosphate, dissolved, as P 1 1 0 0.09 0.09 0.09 -- -- -- -- -- --

Fort Union Formation

Nitrate plus nitrite, dissolved, as N 1 1 0 37 37 37 10 (MCL)2, 100 (Ag) MCL 1 1 1975 37Orthophosphate, dissolved, as P 1 1 0 0.49 0.49 0.49 -- -- -- -- -- --

Lewis Shale

Nitrate plus nitrite, dissolved, as N 5 5 0 0.02 1.1 15 10 (MCL)2, 100 (Ag) MCL 2 2 1975 12, 15Total phosphorus, dissolved, as P 1 1 1 <0.03 <0.03 <0.03 -- -- -- -- -- --Total phosphorus, unfiltered, as P 5 5 1 <0.01 0.02 0.22 -- -- -- -- -- --Orthophosphate, dissolved, as P 5 5 3 <0.01 <0.01 0.43 -- -- -- -- -- --

Mancos Shale

Nitrate plus nitrite, dissolved, as N 12 13 0 0.01 0.34 17 10 (MCL)2, 100 (Ag) MCL 1 1 1978 17Total phosphorus, unfiltered, as P 2 2 0 0.01 0.06 0.12 -- -- -- -- -- --Orthophosphate, dissolved, as P 12 13 5 <0.01 0.03 0.12 -- -- -- -- -- --
Water-Quality Assessment 75

Table 23. Summary statistics for selected nutrient water-quality data and exceedances of Colorado Department of Public Health and Environment water-quality standards for groundwater in the Upper Yampa River watershed, Colorado, 1975 through 1989 and 1998.—Continued[No., number; Min., minimum; Max., maximum; N, nitrogen; <, less than; MCL, maximum contaminant level; Ag, Agriculture; ne, no exceedance; E, estimated; --, no water-quality standard; P, phosphorus. All constituents are reported in milligrams per liter. Number of significant figures for individual constituents may vary among the geologic units because data are from different sources and different analytical periods. Water-quality standards are from Colorado Department of Public Health and Environment (2009b)]

Constituent Total no.

of wells

Total no.

of samples

Total no.

of censored

values1

Min.

value

Median

value

Max.

value

Waterquality 

standard

Exceedances of water-quality standard

Standard No. of wells No. of samples Year(s) Range of values not meeting standard

Mesaverde Group

Nitrite, dissolved, as N 3 3 2 <0.01 <0.01 0.03 1 (MCL), 10 (Ag) ne 0 0 ne neNitrate plus nitrite, dissolved, as N 40 120 13 <0.0.1 0.12 14 10 (MCL)2, 100 (Ag) MCL 1 1 1978 14Total ammonia, dissolved, as N 4 4 0 0.11 0.8 1.8 -- -- -- -- -- --Total phosphorus, dissolved, as P 10 44 9 <0.0.1 0.01 0.07 -- -- -- -- -- --Total phosphorus, unfiltered, as P 9 9 2 <0.01 0.03 0.33 -- -- -- -- -- --Orthophosphate, dissolved, as P 40 82 18 <0.01 0.06 0.98 -- -- -- -- -- --

Precambrian erathem

Nitrate plus nitrite, dissolved, as N 1 1 1 <0.1 <0.1 <0.1 10 (MCL)2, 100 (Ag) ne 0 0 ne neOrthophosphate, dissolved, as P 1 1 0 0.06 0.06 0.06 -- -- -- -- -- --

Upper Cretaceous series

Nitrate plus nitrite, dissolved, as N 1 1 0 1.9 1.9 1.9 10 (MCL)2, 100 (Ag) ne 0 0 ne neOrthophosphate, dissolved, as P 1 1 0 0.03 0.03 0.03 -- -- -- -- -- --

Valley-fill deposits

Nitrate plus nitrite, dissolved, as N 7 7 0 0.01 0.32 8.8 10 (MCL)2, 100 (Ag) ne 0 0 ne neTotal phosphorus, unfiltered, as P 4 4 0 0.03 0.02 0.09 -- -- -- -- -- --Orthophosphate, dissolved, as P 7 7 3 <0.01 0.03 0.12 -- -- -- -- -- --

Unknown geologic units

Nitrite, dissolved, as N 103 139 110 <0.01 <0.01 0.26 1 (MCL), 10 (Ag) ne 0 0 ne neNitrate plus nitrite, dissolved, as N 70 250 114 <0.01 0.06 27 10 (MCL)2, 100 (Ag) MCL 5 11 1988–89 13–27Total ammonia, dissolved, as N 103 139 0 0.03 0.45 5.6 -- -- -- -- -- --Total phosphorus, dissolved, as P 103 189 45 <0.01 0.02 0.76 -- -- -- -- -- --Total phosphorus, unfiltered, as P 13 13 4 <0.01 0.02 0.12 -- -- -- -- -- --Orthophosphate, dissolved, as P 68 215 91 <0.01 0.03 2.4 -- -- -- -- -- --

1Censored values can be expressed as values less than the laboratory reporting level.2The MCL of 10 mg/L is for nitrate, as N.3Exceedances did not occur in every year of the period of record.
76 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

(250 samples) and the Mesaverde Group (120 samples) 

(table 23). Median concentrations were 0.81 mg/L or less for 

all geologic units with two of more samples except for the terrace alluvium (1.5 mg/L) and Lewis Shale (1.1 mg/L). About 

4.5 percent (21 of 467) of samples with nitrate plus nitrite data 

had concentrations that exceeded the CDPHE MCL standard 

of 10 mg/L for nitrate (table 23) (Colorado Department of 

Public Health and Environment, 2009b). About one-half of the 

concentrations greater than 10 mg/L were detected in samples 

collected before 1980, and others were collected during 1988 

and 1989 (table 23). About 24 percent of the wells with sample 

concentrations exceeding the standard were in the Yampa 

coal field. No nitrate plus nitrite concentrations exceeded the 

agricultural-use standard for livestock watering of 100 mg/L.

Data for dissolved total phosphorus were available 

for well samples with no aquifer or geologic unit description (189 samples) and those from the terrace alluvium, 

Mesaverde Group (44 samples each) and Lewis Shale (1 

sample) (table 23). Unfiltered total phosphorus data were 

available for only 42 samples from the flood-plain alluvium, 

Eocene Series, Lewis and Mancos Shales, Mesaverde Group, 

valley-fill deposits, and unknown geologic units (table 23). 

Concentrations of dissolved and unfiltered total phosphorus were 0.33 mg/L or less, except for a concentration of 

0.76 mg/L in a sample from a well (site 355) in an unknown 

geologic unit. About 95 percent of the concentrations were 

less than 0.1 mg/L. The CDPHE has not established waterquality standards for dissolved and unfiltered total phosphorus 

in groundwater.

Trace Elements

Trace-element data were available for 609 samples from 

190 wells (table 19). Samples had concentration data for the 

dissolved constituents and total recoverable iron, listed in 

table 24 and discussed in this report, and concentration data 

for total recoverable copper, dissolved lithium, unfiltered 

and total recoverable manganese, and dissolved vanadium, 

which are not listed in table 24 and are not discussed in this 

report. More than 500 samples had concentration data for dissolved boron, iron, manganese, selenium, and zinc; the fewest 

samples (22) were available for dissolved antimony (table 24).

More than 80 percent of the data for dissolved antimony, 

arsenic, beryllium, cadmium, chromium, cobalt, copper, lead, 

mercury, molybdenum, nickel, selenium, and silver were less 

than or equal to laboratory detection levels (table 24). Low 

concentrations are generally due to small occurrences in soils 

and rocks and (or) low solubility of the elements (Driver 

and others, 1984). All concentrations of dissolved antimony, 

barium, chromium, cobalt, mercury, nickel, and silver met 

CDPHE HH standards, MCLs, SMCLs, and (or) agriculturaluse standards for groundwater (table 25). Concentrations of 

dissolved arsenic, beryllium, copper, lead, molybdenum, and 

selenium in one or two samples for each constituent were 

greater than HH standards, MCLs, and (or) agricultural-use 

standards. Only one sample collected from the flood-plain 

alluvium at site 238 had an arsenic concentration greater than 

the MCL for arsenic of 10 μg/L. The MCL for dissolved beryllium was exceeded in two samples from one well (site 329) 

in an unknown geologic unit. Only one sample collected from 

site 358 in the valley-fill deposit exceeded the agricultural-use 

standard for copper of 200 μg/L. The HH and agricultural-use 

standards for dissolved lead were exceeded in one sample 

from the Mesaverde Group at site 286 near the mouth of 

Middle Creek. The HH standard for dissolved molybdenum 

was exceeded in one sample from the Mancos Shale at site 

467 just northwest of Steamboat Springs. Only one sample 

collected from site 378 in the terrace alluvium exceeded the 

agricultural-use standard for selenium of 20 μg/L. The MCL 

for dissolved cadmium was exceeded in less than 4 percent 

(13 of 329) of samples; 3 samples from the Mesaverde Group 

near Foidel Creek and 10 samples from unknown geologic 

units near Fish Creek and in the area between Grassy and 

Sage Creeks in the Yampa coal field. Four of the samples had 

concentrations that exceeded the cadmium agricultural-use 

standard of 10 μg/L. All dissolved cadmium samples but one 

were from wells in the Yampa coal field.

The highest concentrations (3,600 μg/L or more) were 

detected for dissolved aluminum and boron, dissolved and 

total recoverable iron, and dissolved manganese, strontium, 

and zinc (table 24). All dissolved aluminum concentrations were less than the CDPHE agricultural-use standard 

for livestock watering of 5,000 μg/L. The CDPHE has not 

established a drinking-water standard for dissolved aluminum 

in groundwater. Boron concentrations in about 13 percent 

(70 of 539) of samples exceeded the agricultural-use standard 

of 750 μg/L. Almost 84 percent of these samples were collected from the terrace alluvium. All zinc concentrations were 

less than the CDPHE SMCL of 5,000 μg/L; fewer than one 

percent of samples had zinc concentrations that exceeded the 

agricultural-use standard of 2,000 μg/L. The CDPHE has not 

established groundwater standards for total recoverable iron 

and dissolved strontium. Iron and manganese are discussed in 

the following paragraphs.

Dissolved iron data were available for 574 samples from 

every lithology listed in table 20. Most samples were collected 

from the unknown geologic units (329 samples), Mesaverde 

Group (127 samples) and terrace alluvium (65 samples) 

(table 24). The highest median concentration per geologic unit 

with more than one sample was for samples from the valleyfill deposits (140 μg/L), and the lowest (less than 10 μg/L) 

was for samples from the Browns Park Formation. Individual 

samples with concentrations greater than 2,000 μg/L were 

collected from unknown geologic units (5 samples) and 

Mesaverde Group (3 samples); one sample each was collected 

from the flood-plain alluvium, Mancos Shale, and valley-fill 

deposits. The CDPHE SMCL for dissolved iron of 300 μg/L 

was exceeded in about 10 percent (60 of 574) of samples collected (table 24). Samples with exceedances were most commonly collected from wells in the Mancos Shale, valley-fill 

deposits, and unknown geologic units, between 33 to 43 percent of wells for each grouping. Concentrations exceeding the 
Water-Quality Assessment 77

Table 24. Summary statistics for selected trace element water-quality data and exceedances of Colorado Department of Public Health and Environment water-quality standards for groundwater in the Upper Yampa River watershed, Colorado, 1975 through 1989 and 1998.—Continued[No., number; Min., minimum; Max., maximum; <, less than; Ag, Agriculture; ne, no exceedance; nc, not computed; MCL, maximum contaminant level; SMCL, secondary maximum contaminant level; --, no water-quality standard; HH, human health. All constituents are reported in micrograms per liter. Number of significant figures for individual constituents may vary among the geologic units because data are from different sources and analytical periods. Water-quality standards are from Colorado Department of Public Health and Environment (2009b)]

Constituent Total no. of wells Total no. of samples Total no. of censored values1 Min. value Median value Max. value Water-quality standard Exceedances of water-quality standard No. of wells No. of samples Year(s) Range of values not meeting standard

Upper Yampa River watershed

Aluminum, dissolved 68 327 166 <5 8 4,500 5,000 (Ag) 0 0 ne neAntimony, dissolved 22 22 18 <1 nc 1 6 (MCL) 0 0 ne neArsenic, dissolved 176 446 248 <1 <1 160 10 (MCL), 100 (Ag) 1 1 1975 160Barium, dissolved 24 215 0 14 69 680 2,000 (MCL) 0 0 ne neBeryllium, dissolved 24 215 207 <0.5 nc 6 4 (MCL) 1 2 1988, 1989 4.5, 6.0

100 (Ag) 0 0 ne ne

Boron, dissolved 128 539 4 210 190 4,700 750 (Ag) 24 70 1979–81 760–4,700Cadmium, dissolved 96 329 284 <1 nc 23 5 (MCL) 13 13 1977, 1988–89 6–23

10 (Ag) 4 4 1977, 1989 11–23

Chromium, dissolved 48 251 234 <5 nc <25 100 (MCL, Ag) 0 0 ne neCobalt, dissolved 33 224 209 <2 nc 23 50 (Ag) 0 0 ne neCopper, dissolved 78 273 241 <2 nc 300 1,000 (SMCL) 0 0 ne ne

200 (Ag) 1 1 1975 300

Iron, dissolved 186 574 69 <3 40 39,000 300 (SMCL) 45 60 31975–89 340–39,000

5,000 (Ag) 2 3 1980, 1981 5,100–39,000

Iron, total recoverable 42 105 0 70 2,400 590,000 -- -- -- -- --Lead, dissolved 71 313 296 <1 nc 120 50 (HH), 100 (Ag) 1 1 1977 120Manganese, dissolved 183 548 57 <1 60 3,600 50 (SMCL) 90 284 31975–89 55–3,600

 200 (Ag) 44 141 31975–89 210–3,600

Mercury, dissolved 140 215 201 <0.1 nc 2 10 (Ag) 0 0 ne neMolybdenum, dissolved 135 395 328 <1 nc 74 35 (HH) 1 1 1978 74Nickel, dissolved 49 242 230 <2 nc 50 100 (HH), 200 (Ag) 0 0 ne neSelenium, dissolved 184 594 439 <1 <1 27 50 (MCL) 0 0 ne ne

20 (Ag) 1 1 1979 27

Silver, dissolved 25 216 189 <1 nc <30 50 (HH) 0 0 ne neStrontium, dissolved 50 241 0 7 560 10,000 -- -- -- -- --Zinc, dissolved 156 514 138 <3 20 4,500 5,000 (SMCL) 0 0 ne ne

2,000 (Ag) 3 4 1975, 1978 2,200–4,500

Alluvium, flood plain

Aluminum, dissolved 1 1 0 140 140 140 5,000 (Ag) 0 0 ne neAntimony, dissolved 2 2 2 <1 <1 <1 6 (MCL) 0 0 ne neArsenic, dissolved 13 14 8 <1 <1 160 10 (MCL), 100 (Ag) 1 1 1975 160Boron, dissolved 5 5 2 <20 40 700 750 (Ag) 0 0 ne neCadmium, dissolved 6 6 6 <2 <2 <2 5 (MCL), 10 (Ag) 0 0 ne neCobalt, dissolved 2 2 2 <2 <2 <2 50 (Ag) 0 0 ne neCopper, dissolved 4 4 0 12 20 40 1,000 (SMCL), 200 (Ag) 0 0 ne neIron, dissolved 14 15 2 <10 40 2,500 300 (SMCL) 3 3 31975–80 340–2,500

5,000 (Ag) 0 0 ne ne
78 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009 Table 24. Summary statistics for selected trace element water-quality data and exceedances of Colorado Department of Public Health and Environment water-quality standards for groundwater in the Upper Yampa River watershed, Colorado, 1975 through 1989 and 1998.—Continued [No., number; Min., minimum; Max., maximum; <, less than; Ag, Agriculture; ne, no exceedance; nc, not computed; MCL, maximum contaminant level; SMCL, secondary maximum contaminant level; --, no water-quality standard; HH, human health. All constituents are reported in micrograms per liter. Number of significant figures for individual constituents may vary among the geologic units because data are from different sources and analytical periods. Water-quality standards are from Colorado Department of Public Health and Environment (2009b)] Constituent Total no. of wells Total no. of samples Total no. of censored values1 Min. value Median value Max. value Water-quality standard Exceedances of water-quality standard No. of wells No. of samples Year(s) Range of values not meeting standard Alluvium, flood plain—Continued Iron, total recoverable 1 1 0 12,000 12,000 12,000 -- -- -- -- -- Lead, dissolved 3 3 3 <2 <2 <2 50 (HH), 100 (Ag) 0 0 ne ne Manganese, dissolved 14 15 6 <10 30 620 50 (SMCL) 6 7 31975–80 60–620 200 (Ag) 3 3 1975, 1978 450–620 Mercury, dissolved 13 13 13 <0.1 nc <0.5 10 (Ag) 0 0 ne ne Molybdenum, dissolved 13 13 8 <1 <1 15 35 (HH) 0 0 ne ne Nickel, dissolved 2 2 2 <2 <2 <2 100 (HH), 200 (Ag) 0 0 ne ne Selenium, dissolved 13 14 10 <1 nc 2 50 (MCL), 20 (Ag) 0 0 ne ne Strontium, dissolved 4 4 0 110 150 410 -- -- -- -- -- Zinc, dissolved 13 13 0 20 80 1,500 5,000 (SMCL), 2,000 (Ag) 0 0 ne ne Alluvium, terrace Arsenic, dissolved 22 22 1 <1 1 3 10 (MCL), 100 (Ag) 0 0 ne ne Boron, dissolved 22 88 0 170 1,300 4,700 750 (Ag) 20 65 1978, 1979 800–4,700 Cadmium, dissolved 15 15 15 <2 <2 <2 5 (MCL), 10 (Ag) 0 0 ne ne Chromium, dissolved 22 34 20 <5 10 20 100 (MCL, Ag) 0 0 ne ne Copper, dissolved 1 1 1 <2 <2 <2 1,000 (SMCL), 200 (Ag) 0 0 ne ne Iron, dissolved 22 65 32 <10 20 1,700 300 (SMCL) 2 2 1979 360, 1,700 5,000 (Ag) 0 0 ne ne Manganese, dissolved 22 67 7 <10 70 3,600 50 (SMCL) 19 38 1978, 1979 60–3,600 200 (Ag) 10 13 1978, 1979 210–3,600 Mercury, dissolved 19 19 19 <0.1 <0.1 <0.1 10 (Ag) 0 0 ne ne Selenium, dissolved 22 81 5 <1 4 27 50 (MCL) 0 0 ne ne 20 (Ag) 1 1 1979 27 Zinc, dissolved 22 66 20 <3 15 40 5,000 (SMCL), 2,000 (Ag) 0 0 ne ne Browns Park Formation Arsenic, dissolved 7 7 2 <1 1 3 10 (MCL), 100 (Ag) 0 0 ne ne Boron, dissolved 6 6 1 <20 40 520 750 (Ag) 0 0 ne ne Cadmium, dissolved 4 4 4 <2 <2 <2 5 (MCL), 10 (Ag) 0 0 ne ne Copper, dissolved 3 3 0 16 27 <0.1 1,000 (SMCL), 200 (Ag) 0 0 ne ne Iron, dissolved 7 7 4 <10 <10 50 300 (SMCL), 5,000 (Ag) 0 0 ne ne Manganese, dissolved 7 7 6 <10 nc 110 50 (SMCL) 1 1 1978 110 200 (Ag) 0 0 ne ne Mercury, dissolved 7 7 7 <0.1 <0.1 <0.1 10 (Ag) 0 0 ne ne Molybdenum, dissolved 7 7 6 <1 nc 20 35 (HH) 0 0 ne ne Nickel, dissolved 1 1 1 <2 <2 <2 100 (HH), 200 (Ag) 0 0 ne ne Selenium, dissolved 7 7 6 <1 nc 6 50 (MCL), 20 (Ag) 0 0 ne ne Zinc, dissolved 6 6 0 20 270 830 5,000 (SMCL), 2,000 (Ag) 0 0 ne ne
Water-Quality Assessment 79

Table 24. Summary statistics for selected trace element water-quality data and exceedances of Colorado Department of Public Health and Environment water-quality standards for groundwater in the Upper Yampa River watershed, Colorado, 1975 through 1989 and 1998.—Continued[No., number; Min., minimum; Max., maximum; <, less than; Ag, Agriculture; ne, no exceedance; nc, not computed; MCL, maximum contaminant level; SMCL, secondary maximum contaminant level; --, no water-quality standard; HH, human health. All constituents are reported in micrograms per liter. Number of significant figures for individual constituents may vary among the geologic units because data are from different sources and analytical periods. Water-quality standards are from Colorado Department of Public Health and Environment (2009b)]

Constituent Total no. of wells Total no. of samples Total no. of censored values1 Min. value Median value Max. value Water-quality standard Exceedances of water-quality standard No. of wells No. of samples Year(s) Range of values not meeting standard

Curtis Formation of San Rafael Group

Arsenic, dissolved 1 1 0 1 1 1 10 (MCL), 100 (Ag) 0 0 ne neBoron, dissolved 1 1 0 30 30 30 750 (Ag) 0 0 ne neIron, dissolved 1 1 0 20 20 20 300 (SMCL), 5,000 (Ag) 0 0 ne neManganese, dissolved 1 1 0 20 20 20 50 (SMCL), 200 (Ag) 0 0 ne neMercury, dissolved 1 1 1 <0.1 <0.1 <0.1 10 (Ag) 0 0 ne neMolybdenum, dissolved 1 1 0 5 5 5 35 (HH) 0 0 ne neSelenium, dissolved 1 1 1 <1 <1 <1 50 (MCL), 20 (Ag) 0 0 ne neStrontium, dissolved 1 1 0 560 560 560 -- -- -- -- --Zinc, dissolved 1 1 1 <20 <20 <20 5,000 (SMCL), 2,000 (Ag) 0 0 ne ne

Eocene series

Arsenic, dissolved 1 1 1 <1 <1 <1 10 (MCL), 100 (Ag) 0 0 ne neCobalt, dissolved 1 1 1 <2 <2 <2 50 (Ag) 0 0 ne neIron, dissolved 1 1 0 80 80 80 300 (SMCL), 5,000 (Ag) 0 0 ne neManganese, dissolved 1 1 1 <10 <10 <10 50 (SMCL), 200 (Ag) 0 0 ne neMercury, dissolved 1 1 1 <0.5 <0.5 <0.5 10 (Ag) 0 0 ne neMolybdenum, dissolved 1 1 1 <1 <1 <1 35 (HH) 0 0 ne neSelenium, dissolved 1 1 1 <1 <1 <1 50 (MCL), 20 (Ag) 0 0 ne ne

Fort Union Formation

Arsenic, dissolved 1 1 0 1 1 1 10 (MCL), 100 (Ag) 0 0 ne neIron, dissolved 1 1 0 830 830 830 300 (SMCL) 1 1 1975 830

5,000 (Ag) 0 0 ne ne

Manganese, dissolved 1 1 0 40 40 40 50 (SMCL), 200 (Ag) 0 0 ne neSelenium, dissolved 1 1 0 3 3 3 50 (MCL), 20 (Ag) 0 0 ne ne

Lewis Shale

Arsenic, dissolved 6 6 4 <1 <1 2 10 (MCL), 100 (Ag) 0 0 ne neBoron, dissolved 1 2 0 190 285 380 750 (Ag) 0 0 ne neCadmium, dissolved 1 1 1 <1 <1 <1 5 (MCL), 10 (Ag) 0 0 ne neChromium, dissolved 1 1 0 10 10 10 100 (MCL, Ag) 0 0 ne neCobalt, dissolved 1 1 1 <2 <2 <2 50 (Ag) 0 0 ne neCopper, dissolved 1 1 0 190 190 190 1,000 (SMCL), 200 (Ag) 0 0 ne neIron, dissolved 6 6 0 20 45 1,600 300 (SMCL) 1 1 1975 1,600

5,000 (Ag) 0 0 ne ne

Lead, dissolved 1 1 1 <2 <2 <2 50 (HH), 100 (Ag) 0 0 ne neManganese, dissolved 6 6 3 <10 15 310 50 (SMCL) 2 2 1975 60, 310

200 (Ag) 1 1 1975 310

Mercury, dissolved 6 6 5 <0.5 nc 1 10 (Ag) 0 0 ne neMolybdenum, dissolved 5 5 3 <1 <1 7 35 (HH) 0 0 ne neSelenium, dissolved 6 7 3 <1 1 13 50 (MCL), 20 (Ag) 0 0 ne neZinc, dissolved 6 7 0 20 50 1,700 5,000 (SMCL), 2,000 (Ag) 0 0 ne ne
80 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009 Table 24. Summary statistics for selected trace element water-quality data and exceedances of Colorado Department of Public Health and Environment water-quality standards for groundwater in the Upper Yampa River watershed, Colorado, 1975 through 1989 and 1998.—Continued [No., number; Min., minimum; Max., maximum; <, less than; Ag, Agriculture; ne, no exceedance; nc, not computed; MCL, maximum contaminant level; SMCL, secondary maximum contaminant level; --, no water-quality standard; HH, human health. All constituents are reported in micrograms per liter. Number of significant figures for individual constituents may vary among the geologic units because data are from different sources and analytical periods. Water-quality standards are from Colorado Department of Public Health and Environment (2009b)] Constituent Total no. of wells Total no. of samples Total no. of censored values1 Min. value Median value Max. value Water-quality standard Exceedances of water-quality standard No. of wells No. of samples Year(s) Range of values not meeting standard Mancos Shale Arsenic, dissolved 12 13 9 <1 <1 2 10 (MCL), 100 (Ag) 0 0 ne ne Boron, dissolved 9 9 0 30 130 1,000 750 (Ag) 1 1 1978 1,000 Cadmium, dissolved 3 3 3 <2 <2 <2 5 (MCL), 10 (Ag) 0 0 ne ne Cobalt, dissolved 1 1 1 <2 <2 <2 50 (Ag) 0 0 ne ne Copper, dissolved 5 5 2 <2 22 100 1,000 (SMCL), 200 (Ag) 0 0 ne ne Iron, dissolved 12 13 2 <10 80 3,100 300 (SMCL) 4 4 1978 310–3,100 5,000 (Ag) 0 0 ne ne Manganese, dissolved 12 13 6 <10 20 230 50 (SMCL) 3 3 1978 80–230 200 (Ag) 1 1 1978 230 Mercury, dissolved 10 11 11 <0.1 nc <0.5 10 (Ag) 0 0 ne ne Molybdenum, dissolved 10 11 5 <1 1 74 35 (HH) 1 1 1978 74 Nickel, dissolved 4 4 4 <2 <2 <2 100 (HH), 200 (Ag) 0 0 ne ne Selenium, dissolved 12 13 10 <1 <1 5 50 (MCL), 20 (Ag) 0 0 ne ne Strontium, dissolved 9 9 0 70 330 3,900 -- -- -- -- -- Zinc, dissolved 10 11 1 <20 220 4,500 5,000 (SMCL) 0 0 ne ne 2,000 (Ag) 2 3 1975, 1978 2,200–4,500 Mesaverde Group Aluminum, dissolved 46 58 11 <2 10 520 5,000 (Ag) 0 0 ne ne Antimony, dissolved 16 16 12 <1 <1 1 6 (MCL) 0 0 ne ne Arsenic, dissolved 39 82 26 <1 1 7 10 (MCL), 100 (Ag) 0 0 ne ne Boron, dissolved 33 119 0 30 130 1,000 750 (Ag) 2 3 1980, 1981 760–1,000 Cadmium, dissolved 22 45 42 <1 nc 13 5 (MCL), 10 (Ag) 3 3 1977 11–13 Cobalt, dissolved 1 1 1 <2 <2 <2 50 (Ag) 0 0 ne ne Copper, dissolved 21 24 11 <2 11 44 1,000 (SMCL), 200 (Ag) 0 0 ne ne Iron, dissolved 41 127 10 <3 50 39,000 300 (SMCL) 8 11 31975–82 460–39,000 5,000 (Ag) 1 2 1980, 1981 24,000, 39,000 Iron, total recoverable 46 53 0 70 1,400 590,000 -- -- -- -- -- Lead, dissolved 18 45 44 <1 nc 120 50 (HH), 100 (Ag) 1 1 1977 120 Manganese, dissolved 38 110 11 <1 60 3,000 50 (SMCL) 14 56 31977–86 60–3,000 200 (Ag) 8 39 31977–86 220–3,000 Mercury, dissolved 39 81 71 <0.1 nc 2 10 (Ag) 0 0 ne ne Molybdenum, dissolved 33 69 46 <1 1 34 35 (HH) 0 0 ne ne Nickel, dissolved 11 12 12 <2 <2 <2 100 (HH), 200 (Ag) 0 0 ne ne Selenium, dissolved 41 128 104 <1 nc 7 50 (MCL), 20 (Ag) 0 0 ne ne Silver, dissolved 1 1 1 <1 <1 <1 50 (HH) 0 0 ne ne Strontium, dissolved 2 2 0 190 495 800 -- -- -- -- -- Zinc, dissolved 35 102 13 <3 20 2,200 5,000 (SMCL) 0 0 ne ne

2,000 (Ag) 1 1 1975 2,200
Water-Quality Assessment 81

Table 24. Summary statistics for selected trace element water-quality data and exceedances of Colorado Department of Public Health and Environment water-quality standards for groundwater in the Upper Yampa River watershed, Colorado, 1975 through 1989 and 1998.—Continued[No., number; Min., minimum; Max., maximum; <, less than; Ag, Agriculture; ne, no exceedance; nc, not computed; MCL, maximum contaminant level; SMCL, secondary maximum contaminant level; --, no water-quality standard; HH, human health. All constituents are reported in micrograms per liter. Number of significant figures for individual constituents may vary among the geologic units because data are from different sources and analytical periods. Water-quality standards are from Colorado Department of Public Health and Environment (2009b)]

Constituent Total no. of wells Total no. of samples Total no. of censored values1 Min. value Median value Max. value Water-quality standard Exceedances of water-quality standard No. of wells No. of samples Year(s) Range of values not meeting standard

Precambrian erathem

Arsenic, dissolved 1 1 1 <1 <1 <1 10 (MCL), 100 (Ag) 0 0 ne neCopper, dissolved 1 1 1 <2 <2 <2 1,000 (SMCL), 200 (Ag) 0 0 ne neIron, dissolved 1 1 0 660 660 660 300 (SMCL) 1 1 1978 660

5,000 (Ag) 0 0 ne ne

Manganese, dissolved 1 1 0 110 110 110 50 (SMCL) 1 1 1978 110

200 (Ag) 0 0 ne ne

Mercury, dissolved 1 1 1 <0.1 <0.1 <0.1 10 (Ag) 0 0 ne neMolybdenum, dissolved 1 1 1 <1 <1 <1 35 (HH) 0 0 ne neSelenium, dissolved 1 1 1 <1 <1 <1 50 (MCL), 20 (Ag) 0 0 ne neStrontium, dissolved 1 1 0 20 20 20 -- -- -- -- --Zinc, dissolved 1 1 0 260 260 260 5,000 (SMCL), 2,000 (Ag) 0 0 ne ne

Upper Cretaceous series

Arsenic, dissolved 1 1 1 <1 <1 <1 10 (MCL), 100 (Ag) 0 0 ne neIron, dissolved 1 1 0 20 20 20 300 (SMCL), 5,000 (Ag) 0 0 ne neManganese, dissolved 1 1 0 60 60 60 50 (SMCL) 1 1 1975 60

200 (Ag) 0 0 ne ne

Selenium, dissolved 1 1 0 3 3 3 50 (MCL), 20 (Ag) 0 0 ne ne

Valley-fill deposits

Arsenic, dissolved 6 6 6 <1 <1 <1 10 (MCL), 100 (Ag) 0 0 ne neCopper, dissolved 1 1 0 300 300 300 1,000 (SMCL) 0 0 ne ne

200 (Ag) 1 1 1975 300

Iron, dissolved 7 7 1 <10 140 3,100 300 (SMCL) 3 3 1975 1,300, 3,100

5,000 (Ag) 0 0 ne ne

Lead, dissolved 1 1 1 <2 <2 <2 50 (HH), 100 (Ag) 0 0 ne neManganese, dissolved 7 7 3 <10 20 70 50 (SMCL) 1 1 1975 70

200 (Ag) 0 0 ne ne

Mercury, dissolved 4 4 4 <0.5 <0.5 <0.5 10 (Ag) 0 0 ne neMolybdenum, dissolved 4 4 3 <1 <1 2 35 (HH) 0 0 ne neSelenium, dissolved 7 7 5 <1 <1 4 50 (MCL), 20 (Ag) 0 0 ne neZinc, dissolved 4 4 0 20 25 170 5,000 (SMCL), 2,000 (Ag) 0 0 ne ne
82 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009 Table 24. Summary statistics for selected trace element water-quality data and exceedances of Colorado Department of Public Health and Environment water-quality standards for groundwater in the Upper Yampa River watershed, Colorado, 1975 through 1989 and 1998.—Continued [No., number; Min., minimum; Max., maximum; <, less than; Ag, Agriculture; ne, no exceedance; nc, not computed; MCL, maximum contaminant level; SMCL, secondary maximum contaminant level; --, no water-quality standard; HH, human health. All constituents are reported in micrograms per liter. Number of significant figures for individual constituents may vary among the geologic units because data are from different sources and analytical periods. Water-quality standards are from Colorado Department of Public Health and Environment (2009b)] Constituent Total no. of wells Total no. of samples Total no. of censored values1 Min. value Median value Max. value Water-quality standard Exceedances of water-quality standard No. of wells No. of samples Year(s) Range of values not meeting standard Unknown geologic units Aluminum, dissolved 103 268 155 <1 7 4,500 5,000 (Ag) 0 0 ne ne Antimony, dissolved 4 4 4 <1 <1 <1 6 (MCL) 0 0 ne ne Arsenic, dissolved 66 291 189 <1 <1 8 10 (MCL), 100 (Ag) 0 0 ne ne Barium, dissolved 103 215 0 14 69 680 2,000 (MCL) 0 0 ne ne Beryllium, dissolved 24 215 207 <0.5 nc 6 4 (MCL) 1 2 1988, 1989 4.5, 6.0 100 (Ag) 0 0 ne ne Boron, dissolved 51 309 1 210 150 1,400 750 (Ag) 1 1 1978 1,400 Cadmium, dissolved 45 255 213 <1 nc 23 5 (MCL) 10 10 1988–89 6–23 10 (Ag) 1 1 1989 23 Chromium, dissolved 25 216 214 <5 nc 18 100 (MCL, Ag) 0 0 ne ne Cobalt, dissolved 103 218 203 <2 nc 23 50 (Ag) 0 0 ne ne Copper, dissolved 41 233 226 <2 nc <50 1,000 (SMCL), 200 (Ag) 0 0 ne ne Iron, dissolved 62 329 18 <3 40 5,100 300 (SMCL) 22 34 31975–89 340–5,100 5,000 (Ag) 1 1 1981 5,100 Iron, total recoverable 20 51 0 280 4,000 190,000 -- -- -- -- -- Lead, dissolved 103 263 247 <1 nc <50 50 (HH), 100 (Ag) 0 0 ne ne Manganese, dissolved 72 318 14 <1 60 2,600 50 (SMCL) 42 174 31975–89 55–2,600 200 (Ag) 21 84 31975–89 210–2,600 Mercury, dissolved 39 71 68 <0.1 nc <0.5 10 (Ag) 0 0 ne ne Molybdenum, dissolved 60 283 255 <1 nc <50 35 (HH) 0 0 ne ne Nickel, dissolved 31 223 211 <2 nc <50 100 (HH), 200 (Ag) 0 0 ne ne Selenium, dissolved 71 332 293 <1 nc 11 50 (MCL), 20 (Ag) 0 0 ne ne Silver, dissolved 103 215 188 <1 nc <30 50 (HH) 0 0 ne ne Strontium, dissolved 26 217 0 7 680 1,000 -- -- -- -- -- Zinc, dissolved 58 303 103 <3 9 1,200 5,000 (SMCL), 2,000 (Ag) 0 0 ne ne 1Censored values can be expressed as values less than the laboratory reporting level.

2The minimum censored value is greater than the minimum detected value that is shown. 3Exceedances did not occur in every year of the period of record.
Macroinvertebrate Data 83

dissolved iron SMCL were slightly more common in samples 

from wells in the Yampa coal field (28 percent of wells) than 

samples from wells not in the coal field (20 percent of wells). 

Only three samples, two from a well in the Mesaverde Group 

and one from a well in an unknown geologic unit, had concentrations that exceeded the dissolved iron agricultural-use 

standard of 5,000 μg/L.

Data for total recoverable iron were available for only 

105 samples (table 24). A total of 51 and 53 samples were 

from unknown geologic units and the Mesaverde Group, 

respectively, and one sample was from the flood-plain alluvium. Median concentrations for samples from unknown 

geologic units and the Mesaverde Group were 4,000 and 

1,400 μg/L, respectively. Concentrations greater than 

10,000 μg/L were detected in samples from wells in unknown 

geologic units, the Mesaverde Group, and the flood-plain alluvium near Fish, Trout, and Grassy Creeks in the Yampa coal 

field. Reducing conditions in the subsurface in the coal field 

area could be causing the high concentrations of dissolved and 

total recoverable iron. The CDPHE has not established a total 

recoverable iron standard for groundwater.

Dissolved manganese data were available for all geologic units, especially unknown geologic units (318 samples), 

Mesaverde Group (110 samples), and terrace alluvium (67 

samples) (table 24). Median concentrations were 30 μg/L or 

less for samples from the flood-plain alluvium, Browns Park 

Formation, and Lewis and Mancos Shales; the median for the 

Browns Park Formation was the lowest at less than 10 μg/L. 

Median dissolved manganese concentrations for the terrace 

alluvium (70 μg/L), Mesaverde Group, and unknown geologic 

units (60 μg/L each) were greater than the CDPHE SMCL 

for manganese of 50 μg/L, as were single concentrations in 

samples from the Upper Cretaceous series (60 μg/L), valleyfill deposits (70 μg/L), and Precambrian erathem (110 μg/L) 

(table 25). In total, the CDPHE SMCL for dissolved manganese was exceeded in concentrations from more than one-half 

(284 of 548) of the samples. Between 51 and 57 percent of 

samples each from the terrace alluvium, Mesaverde Group 

and unknown geologic units had concentrations greater than 

the SMCL (table 24). Samples from most (86 percent) of the 

wells in the terrace alluvium had concentrations greater than 

the standard. Exceedances also were common for wells in the 

Mesaverde Group (37 percent of wells) and unknown geologic 

units (58 percent of wells). Wells with concentrations exceeding the SMCL were concentrated in the Yampa coal field 

(58 percent of wells) and not in noncoal field areas (26 percent of wells). About 26 percent of groundwater samples also 

had dissolved manganese concentrations that exceeded the 

CDPHE agricultural-use standard (table 24).

Analysis of concentration data for groundwater samples 

indicates that water from wells in the flood-plain alluvium and 

Browns Park Formation would be more suitable for domestic or 

agricultural use than water from wells in the Lewis and Mancos 

Shales and Mesaverde Group. Suitability of water from wells 

in the Curtis Formation, Eocene series, Fort Union Formation, 

Precambrian erathem, Upper Cretaceous series, and valley-fill 

deposits for domestic or agricultural use could not be determined because too few data were available for analysis.

Macroinvertebrate Data

Data for macroinvertebrate communities and population were available for 66 stream sites (62 unique site locations) in the UYRW for various periods of time between 

1975 and 2008 (fig. 18, appendix 6). Data consist of counts 

of the number of individuals within a given taxa. About 38 

percent (25 of 66) of sites were sampled once by the USGS 

during August and September 1975. These data are available at http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml, 

accessed June 2012). The CDPHE collected macroinvertebrate data at 37 sites during most years from 1997 through 

2008. Sample collection occurred during April and July 

through October, and three or fewer samples were collected 

at each site. Data were made available to this study from 

the state of Colorado Ecological Data Application System 

(Chris Theel, Colorado Department of Public Health and 

Environment, written commun., 2009). Most of the data 

were included in an Ecological Monitoring and Assessment 

Program report (Beyea and Theel, 2007). Data on macroinvertebrate communities and population have also been 

collected by GEI Consultants, Inc., for the City of Steamboat 

Table 25. Trace elements with Colorado Department of Public 

Health and Environment water-quality standards for groundwater 

and presence or absence of exceedances for samples collected 

in the Upper Yampa River watershed, Colorado, 1975 through 1989 

and 1998.

[--, no water-quality standard. Number in parentheses after “Yes” is number of 

samples with exceedances of the water-quality standard)

Constituent

Exceedance of water-quality standard

Maximum

contaminant

level 

Humanhealth

Secondary

maximum

contaminant

level

Agriculturaluse

Aluminum -- -- -- No

Antimony No -- -- --

Arsenic Yes (1) -- -- Yes (1)

Barium No -- -- --

Beryllium Yes (2) -- -- No

Boron -- -- -- Yes (70)

Cadmium Yes (13) -- -- Yes (4)

Chromium No -- -- No

Cobalt -- -- -- No

Copper -- -- No Yes (1)

Iron -- -- Yes (60) Yes (3)

Lead -- Yes (1) -- Yes (1)

Manganese -- -- Yes (284) Yes (141)

Mercury -- -- -- No

Molybdenum -- Yes (1) -- --

Nickel -- No -- No

Selenium No -- -- Yes (1)

Silver -- No -- --

Zinc -- -- No Yes (4)
84 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Figure 18. Location of stream sites with macroinvertebrate data, Upper Yampa River watershed, Colorado, 1975 through 2008.

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Grassy Creek

Dry Creek

First Creek

Trout Creek

Elk River Lost Dog Cr

Fish Cr

Walton Creek

Bushy Cr

Yampa River

Morrison Creek

Chimney CreekChimney C

B

reek

ear River

Littl e Mo rrison

Creek

Mad Creek

Oat Creek

Fish Creek

Foidel Creek

Sage Creek

Wolf Creek

Yampa River

Elkhead Cr Elkhead Cr

Elkhead

Reservoir

Elkhead

Reservoir

Pearl

Lake

Steamboat

Lake

Stillwater

Reservoir

Stillwater

Reservoir

Lake

Catamount

Stagecoach

Reservoir

Stagecoach

Reservoir

Yamcolo

Reservoir

Yamcolo Reservoir

Lake

Elbert

Fish Creek

Reservoir

Long Lake

Reservoir

6

7

180

22

27

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185 43

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137

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150

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152

154

155

162

169

Service Creek

Yampa River

Yampa River 

subwatershed 1

Yampa River 

subwatershed 2

Elk River

subwatershed

Elkhead Creek

subwatershed

Yampa River 

subwatershed 4

Yampa River 

subwatershed 2

Elk River

subwatershed

Elkhead Creek

subwatershed

Yampa River 

subwatershed 4

Yampa River 

subwatershed 3

Base from U.S. Geological Survey digital data,

1:100,000, Universal Transverse Mercator, 

Zone 13 North, North American Datum of 1983

Enlargement of 

Steamboat Springs area

0 5 10 MILES

0 5 10 KILOMETERS

107°15'

107°00'

106°45'

40°00'

40°15'

40°30'

40°45'

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Walton Creek

ButcherknifeCree k

SpringCreek

Soda Creek

Fish CreekFish Creek

Burgess CreekBurgess Creek

Priest Creek

Yampa River 133

153 176

54

136

10

133

153 176

175 54

136

174 10

EXPLANATION

# Macroinvertebrate sampling site

 and site number (appendix 6)

6

Steamboat

Springs

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#
Synthesis of Water-Quality Data in the Upper Yampa River Watershed 85

Springs. Population data for various taxa were available for 

four sites on the Yampa River within the city limits for one 

day each during the middle of September 2005 and 2007, and 

late August 2008 (GEI Consultants, Inc., 2007, 2008). Data 

were collected to determine whether changes in the macroinvertebrate community occurred throughout the study reach 

or over time. Macroinvertebrate data from the CDPHE and 

GEI Consultants, Inc., are available at the Colorado Data 

Sharing Network website http://www.coloradowaterdata.org/

awqmsportal.html (accessed June 2012), which is a project of 

the Colorado Water Quality Monitoring Council.

Detailed analysis of the macroinvertebrate data was 

beyond the scope of this report. However, results of macroinvertebrate sampling at four Yampa River sites within 

the Steamboat Springs city limits from the 2008 GEI 

Consultants, Inc., report are summarized in this paragraph 

(GEI Consultants, Inc., 2008). For the 2008 sampling effort, 

density (number of individuals per square meter) was the highest at the most downstream site. Insects were the most commonly collected taxa throughout the study reach. Water mites, 

crustaceans, snails, and clams occurred in small numbers in 

the reach. Segmented worms (Family Naididae) increased 

in density from upstream to downstream and represented, 

on average, about 43 percent of the individuals collected at 

the most downstream site. Naid worms are more tolerant of 

organic pollution than beetles and caddisflies, the dominant 

taxon at the upstream sites (GEI Consultants, Inc., 2008). 

Most of the macroinvertebrates collected in the study reach, 

however, were tolerant of diverse environmental conditions. 

Many of the changes in community characteristics during the 

years from 2005 through 2008 occurred throughout the study 

reach. This may indicate that changes in community characteristics throughout the reach are due to upstream effects or 

large-scale environmental factors rather than changes in water 

quality within the reach (GEI Consultants, Inc., 2008).

Synthesis of Water-Quality Data in the 

Upper Yampa River Watershed

The assessment of water quality of streams, lakes, reservoirs, and groundwater in the UYRW was based on data collected at selected sites for various periods from 1975 through 

2009. Data were retrieved from the UYRW water-quality 

database (http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml, 

accessed June 2012). A number of quality-assurance procedures were applied to the data. For a large portion of the 

water-quality data, however, limited metadata and (or) qualityassurance data were available. For these data, it is assumed 

that measurements made at the time of sampling and results 

from laboratory analyses are of good quality.

The number of sites sampled in the UYRW and the 

amount of data collected varied spatially and temporally. 

Results of the assessment indicate that the quality of surface 

water is likely controlled by three primary factors: geology, 

streamflow, and land use. The quality of groundwater is a 

function of various physical and geochemical processes, 

including precipitation, the depositional environment of 

aquifer sediment, type of sediments that groundwater moves 

through, dissolution of soluble minerals in rocks and soils, and 

ion exchange reactions.

The water quality of surface water in the UYRW 

depends in large part on the geology underlying the drainage basin for a stream or water body, which, in turn, affects 

the quality of groundwater discharging to surface water. 

Drainage basins in the eastern one–third of the UYRW, most 

commonly those in Yampa River subwatershed 2 and the 

Elk River subwatershed, are underlain primarily by igneous 

and metamorphic rocks that are resistant to the weathering action of water. With less weathering, a small amount of 

dissolved constituents may be present in surface water and 

groundwater. Median values of specific conductance, hardness, ANC, dissolved solids, and suspended sediment for 

stream samples from Yampa River subwatershed 2 and the Elk 

River subwatershed were lowest for all subwatersheds in the 

UYRW. Water samples from high-altitude lakes and reservoirs in these two subwatersheds also had very low values 

for specific conductance (maximum value of 34 μS/cm) and 

hardness and ANC (maximum values of 17.9 mg/L or less). 

Low ANC values for streams and water bodies in the eastern 

one-third of the watershed and other areas such as the Flat 

Tops Wilderness area indicate that some surface waters in 

the UYRW are sensitive to inputs of acidic deposition from 

precipitation, primarily because the water, soil types, and 

rocks have little capacity to buffer acidic inputs. Groundwater 

samples from two wells in Yampa River subwatershed 2 that 

tap in the Precambrian erathem, a geologic unit composed of 

igneous and metamorphic rocks, had the lowest median specific conductance (163 μS/cm) for the sampled geologic units 

in the UYRW.

Drainage basins in the western two-thirds of the watershed, including Yampa River subwatersheds 3 and 4 and the 

Elkhead Creek subwatersheds, are underlain primarily by 

Cretaceous- and Tertiary-age sedimentary rocks (primarily 

sandstones and shales) deposited in marine and nonmarine 

environments. The sedimentary rocks are more susceptible to 

the weathering action of water than igneous and metamorphic 

rocks, which can result in a large amount of dissolved constituents in surface water and groundwater in areas with sedimentary rocks. Materials weathered from sedimentary rocks also 

can contain a large amount of trace elements. Median values 

of specific conductance, hardness, ANC, dissolved solids, 

and suspended sediment for stream samples from Yampa 

River subwatersheds 3 and 4 were highest for all subwatersheds in the UYRW. Median values of specific conductance 

for samples from wells completed in the sedimentary Lewis 

Shale and the Mesaverde Group, primarily in Yampa River 

subwatersheds 3 and 4, were 1,000 μS/cm or more. These high 

values can occur in surface water and groundwater because of 

natural conditions.
86 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Differences in specific conductance and median concentrations of dissolved constituents (dissolved solids, sulfate, 

chloride, and others) in groundwater from the sedimentary 

geologic units with more than one sample reflect differences 

in the depositional environment of aquifer sediments, type 

of sediments that groundwater moves through, dissolution of 

soluble minerals in rocks and soils, and ion exchange reactions. Specific conductance was typically lower in samples 

from wells in the Browns Park Formation than in samples 

from wells in other sedimentary geologic units, as were 

median concentrations of dissolved solids, and dissolved 

sulfate and chloride. This most likely is due to the riverine 

depositional environment of the Browns Park Formation, 

rather than a marine or marine-nonmarine environment, and 

the absence of shale. The highest median concentrations of 

dissolved sulfate and chloride were in samples from wells 

completed in the terrace alluvium. These wells are located in 

one small area of the UYRW downstream from Sage Creek. 

Elevated sulfate and chloride concentrations could result from 

insufficient leaching of material from the alluvium because of 

the semi-arid climate. Elevated sulfate concentrations could 

also occur naturally because of geochemical processes involving gypsum and oxidation of other minerals in the subsurface.

Values of pH in stream water and groundwater samples 

less than the CDPHE standard minima were not as common in 

the UYRW as in other mountain watersheds in Colorado. Unlike 

the UYRW, low pH values in stream water and groundwater 

in other mountain areas can occur naturally from mineralized 

bedrock and (or) result from acidic drainage in hard-rock mining areas (Runkel and others, 2007). Mineralized bedrock and 

hard-rock mining are not common in the UYRW. In the Yampa 

coal field, primarily in Yampa River subwatersheds 3 and 4, all 

pH values in stream-water samples with the exception of one 

were greater than 7.1, and about 96 percent of well samples had 

pH values greater than 6.5. The absence of acidic coal-mine 

drainage in the UYRW when compared to other areas in the 

country is likely because of the low sulfur content of Colorado 

coal (Wentz, 1974). With a low amount of sulfur, sulfuric acid is 

unlikely to form in streams and groundwater. Stream water and 

groundwater in the Yampa coal field also have a high capacity to 

buffer inputs of acidic water.

Attainment of CDPHE water-quality standards for surface water was met for many stream water sites. Attainment 

of the aquatic-life standard was not met at 15 sites for dissolved copper, total recoverable iron, or dissolved selenium. 

Only one or two groundwater samples had concentrations 

of dissolved arsenic, lead, molybdenum, and beryllium that 

exceeded CDPHE standards, and concentrations of dissolved 

cadmium exceeded the standard in less than 4 percent of 

samples. Exceedances of standards for dissolved iron and 

manganese were more common. Attainment of CDPHE stream 

water-quality standard for these two trace elements was not 

met at 3 and 18 sites, respectively. The CDPHE SMCLs for 

dissolved iron and manganese in groundwater were exceeded 

in about 10 and more than 50 percent of samples, respectively. 

Elevated concentrations of dissolved iron and manganese can 

be common in surface water and groundwater. Iron is associated with a variety of minerals in igneous and sedimentary 

rocks and is present in organic materials. Many of the minerals with iron also have manganese. Iron and manganese in 

groundwater are probably affected by reduction-oxidation 

processes. Portions of five stream segments in the UYRW are 

on the CDPHE 2012 303(d) lists for impairment or monitoring 

or evaluation for trace element contamination, specifically for 

total recoverable iron, lead, manganese, mercury, selenium, 

and (or) zinc.

Changes in streamflow drive seasonal variability in specific conductance and other properties and constituents. Values 

of specific conductance, for example, were lowest during 

snowmelt runoff when there was increased dilution and little 

interaction between water and soil or rock and higher during 

most other times of the year when streamflow is lower and 

base flow from groundwater is the major source of water in a 

stream. Concentrations of constituents that bind to particulate 

matter, such as phosphorus and iron, can be higher during the 

initial phase of snowmelt runoff as material that is washed off 

the land surface drains into streams. Similarly, concentrations 

of suspended sediment were highest during snowmelt runoff.

In the UYRW, as in other mountainous watersheds in 

Colorado, land and water use and changes in the uses can also 

affect water quality of a stream, including water temperature 

and the presence of total phosphorus and E. coli. One issue 

of concern related to these changes is water temperature in 

the main stem of the Yampa River. Many temperature values 

measured at the Yampa River at Steamboat Springs (site 153) 

from 2002 through 2005, particularly those measured during late July and early August, were not in attainment of the 

CDPHE June–September or October–May standards for 

cold water. Higher water temperature could be the result of 

reduced streamflow during drought but also could result from 

reduced streamflow due to upstream hydrologic modifications 

and changes in the river channel. The Yampa River from the 

confluence with Oak Creek downstream to the confluence with 

Elkhead Creek is on the CDPHE 2012 303(d) monitoring and 

evaluation list due to high water temperature, which can stress 

aquatic life. Aquatic life can also be affected by large amounts 

of nutrients that promote excessive algal growth (eutrophication) and deplete oxygen levels in a water body.

Concentrations of unfiltered total phosphorus greater than 

laboratory detections levels were detected in samples collected 

from streams throughout the watershed. Sources of phosphorus to streams in the UYRW can include some sedimentary 

rocks (coal beds in the Mesaverde Group), urban and agricultural runoff, wastewater-treatment-plant effluent, and animal 

waste. About 14 percent of samples had individual values of 

unfiltered total phosphorus that were greater than USEPA recommendations to prevent eutrophication. These samples were 

collected in Yampa River subwatersheds 1, 2, and 3 and the 
Summary 87

Elkhead Creek subwatershed. There was a statistically significant upward trend in flow-adjusted concentrations of unfiltered total phosphorus for Yampa River at Steamboat Springs 

(site 153) for 1997 through 2008. From 2000 through 2008, 

the population of Routt County grew by more than 18 percent 

and was largely driven by recreation-related tourism, including 

second-home development and conversion of undeveloped or 

agricultural land to urban land.

The bacterium E. coli, which can come from recreational 

water users, wildlife, livestock, and septic systems, was 

detected at concentrations greater than the CDPHE waterquality standard in five samples collected from three sites 

during 1994, 1999, 2001, and 2003. Three stream segments 

are on the CDPHE 2012 303(d) list of impaired waters or the 

monitoring and evaluation list for E. coli.

Many of the physical properties or constituents analyzed for this study probably would not be issues of concern 

for aquatic life, human health, or agricultural use of surface 

water and groundwater; concentrations at many sites were 

less than laboratory detections levels or less than CDPHE 

water-quality standards. Exceedances of standards for some 

constituents also probably would not be issues of concern 

because exceedances were based on older data (data collected 

before 20 years ago), although recent data are not available 

for verification. For example, data for four of five sites not 

in attainment of the CDPHE total recoverable iron standard 

for streams were collected before 1983. Periods of exceedances are listed in tables 10 and 21–24. Exceedances for some 

constituents, arsenic in groundwater, for example, may occur 

for only one or a few samples and may represent very localized water-quality conditions. Constituents that are issues of 

concern for aquatic life, human health, or suitability of water 

for various uses include those on the CDPHE 2012 303(d) list 

of impaired waters or monitoring or evaluation list for surface 

water. Other constituents in stream water or groundwater that 

are or could be issues of concern include those that commonly 

have concentrations that exceed standards or that could affect 

technical qualities of water. This could include unfiltered 

sulfate, unfiltered total phosphorus, and dissolved copper in 

stream water; pH, unfiltered nitrate plus nitrite, and dissolved 

copper in groundwater; and hardness, dissolved solids, iron, 

and manganese in stream water and groundwater.

This assessment of water-quality data for streams and 

groundwater in the UYRW illustrates the need for consistent 

(throughout a year and for many years) long-term data collection at key sites for temporal trend analysis and to identify 

emerging changes in water quality. Only three stream sites 

in the UYRW had sufficient (10 years or more of at least 

quarterly data collection ending after 2000 and less than 

10 percent censored data) long-term data to test for temporal 

trends in specific conductance. Trend analysis of data for other 

constituents, including other physical properties, dissolved 

solids, selected major ions, total phosphorus, and some trace 

elements, could be conducted for only one site because of data 

requirements. Few stream sites had data for 10 years or more. 

For many sites, there were yearly gaps in data collection. 

Analysis of water-quality data for groundwater was restricted 

to data collected from 1975 through 1989 and during 1998. 

No groundwater-quality data were in the UYRW water-quality 

database for 1990 through 1997, and there were no recent 

data (collected after 1998) in the database. About 66 percent 

of wells were sampled only once. Additional information on 

dissolved oxygen concentrations in groundwater and geologic units and aquifers that wells tap would be helpful for 

assessment of groundwater quality. Data on dissolved oxygen 

concentrations are needed for determining reduction-oxidation

processes in groundwater; the concentration data only were 

available for 10 percent of wells sampled. Comparison of 

groundwater-quality data to geologic units and aquifers that 

wells tap was restricted to about 70 percent of wells. Wellcompletion information of this type was not available for 

about 30 percent of wells with water-quality data.

Summary

The Yampa River is a highly valued resource known for 

its biological diversity, largely unaltered natural condition, 

and generally high water quality. The Upper Yampa River 

watershed (UYRW, the Elkhead Creek subwatershed and the 

Yampa River watershed upstream from Elkhead Creek) is 

undergoing increased land and water development to support growing municipal demands, recreational tourism, and 

second-home development that present water-quality challenges. In response to the needs of stakeholders in the UYRW, 

the U.S. Geological Survey, in cooperation with Routt County, 

the Colorado Water Conservation Board, and the City of 

Steamboat Springs, initiated a study in 2009 to compile waterquality and macroinvertebrate data for the UYRW and assess 

water-quality conditions. For selected physical properties 

and chemical constituents in samples collected from streams, 

lakes, reservoirs, and groundwater wells in the UYRW, this 

report: (1) characterizes available data through statistical 

summaries, (2) evaluates the spatial and temporal distribution 

of water-quality conditions, (3) identifies temporal trends in 

water quality, where possible, (4) provides comparisons of the 

data to federal and state water-quality standards and recommendations, and (5) identifies factors affecting the quality 

of water. In addition, the availability and characteristics of 

macroinvertebrate data collected in the UYRW are described.

The UYRW drains approximately 1,800 square miles 

west of the Continental Divide in northwestern Colorado. 

The watershed extends from the Williams Fork and Flat 

Top Mountains to the Gore and Park Ranges and from the 

Continental Divide to, and including, the Elkhead Creek 

subwatershed. The UYRW is almost entirely contained within 

Routt County, with small portions in Grand, Garfield, Jackson, 

Moffat, and Rio Blanco Counties.
88 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Water-quality data for selected physical properties and 

chemical constituents in samples collected by federal, state, 

and local agencies from streams, lakes, reservoirs, and groundwater wells in the UYRW for various periods from 1975 

through 2009 are assessed. The data used in the assessment are 

available in a web-based repository at http://rmgsc.cr.usgs.gov/

cwqdr/Yampa/index.shtml. A number of quality-assurance 

procedures were applied to the data. For a large portion of the 

water-quality data, however, limited metadata and (or) qualityassurance data were available. For all data that could not be 

quality assured, it is assumed that measurements made at the 

time of sampling and results from laboratory analyses are of 

good quality.

Stream water-quality data collected by seven federal, 

state, or local agencies from 1975 through 2009 were compiled for 211 sites (176 unique site locations). Because streams 

in the UYRW can have distinct water-quality characteristics 

based on location in the watershed, the watershed was divided 

into six subwatersheds for data analysis:

• Yampa River and tributaries upstream from Chuck Lewis 

State Wildlife Area (Yampa River subwatershed 1);

• Yampa River and tributaries from Chuck Lewis State 

Wildlife Area to Elk River confluence (Yampa River 

subwatershed 2);

• Elk River and tributaries (Elk River subwatershed);

• Yampa River and tributaries from Elk River confluence 

to Town of Hayden (Yampa River subwatershed 3);

• Yampa River and tributaries from Town of Hayden 

to Elkhead Creek confluence (Yampa River 

subwatershed 4); and

• Elkhead Creek and tributaries (Elkhead Creek 

subwatershed).

A total of 5,861 stream-water samples were included in 

the assessment; data were collected from 1975 through 2009 

for physical properties, dissolved solids, major ions, nutrients, 

trace elements, uranium, coliform bacteria, and suspended 

sediment. Data were collected every year at only one mainstem site on the Yampa River. Physical-property data were 

available for almost all samples. Samples for dissolved solids, 

major ions, nutrients, and trace elements also were commonly 

collected. About 13 percent of sites had data for more than 50 

samples; in contrast, almost one-half of sites had data for five 

or fewer samples.

Physical properties in stream water analyzed for this 

study included specific conductance, pH, water temperature, 

dissolved oxygen, hardness, and acid neutralizing capacity. 

Specific conductance, which is proportional to the concentration of major dissolved constituents in water, was commonly 

low (less than 200 microsiemens per centimeter at 25 degrees 

Celsius (μS/cm)) in headwater tributaries with drainage basins 

that overlie igneous and metamorphic rocks that are resistant to the weathering action of water. Values greater than 

1,000 μS/cm were most common in areas with sedimentary 

rocks that are susceptible to weathering. There was a statistically significant downward trend in specific conductance at the 

site 153 (Yampa River at Steamboat Springs).

The pH of a water sample is a measure of how acidic 

or alkaline the water is. Median pH values were lowest in 

the Elk River subwatershed and highest in Yampa River 

subwatershed 1 and the Elkhead Creek subwatershed. Fewer 

than 3 percent of pH values were outside the acceptable range 

established by the Colorado Department of Public Health and 

Environment (CDPHE) for protection of aquatic life. Water 

temperature varied depending on the altitude of a site and 

climate at the site. Water temperature for main-stem Yampa 

River sites increased in a downstream direction. For Yampa 

River at Steamboat Springs (site 153), water temperature 

on some days did not meet CDPHE acute and chronic coldwater standards for aquatic-life protection for the periods of 

June through September and October through May. This was 

the only site in the UYRW with a continuous record of water 

temperature. Dissolved oxygen is the measurement of the 

oxygen in water that is available to aquatic life. Concentrations of dissolved oxygen in UYRW streams were inversely 

related to water temperature. About 99 percent of sites met the 

CDPHE aquatic-life standard for dissolved oxygen. Streams 

with drainage basins underlain by igneous and metamorphic 

rocks tended to have softer water and a lower capacity to neutralize inputs of acidic water than streams with drainage basins 

underlain by sedimentary rocks.

The spatial distribution of dissolved solids and major 

ions (calcium, magnesium, sodium, potassium, bicarbonate, 

carbonate, sulfate, chloride, fluoride, and silica) in UYRW 

stream water was similar to that for specific conductance. All 

but about 4 percent of sites were in attainment of the CDPHE 

water-supply standard for unfiltered sulfate. Concentrations 

of major ions and dissolved solids in streams were typically 

lower during snowmelt runoff in May and June than at other 

times of the year primarily because of the water source and 

increased volume of streamflow. There was a statistically 

significant downward trend in dissolved solids concentrations 

at Yampa River at Steamboat Springs (site 153).

Nitrogen and phosphorus are essential nutrients for plants 

and animals, but high concentrations can cause excessive 

algal growth in surface waters. About 85 percent of dissolved 

nitrite concentrations in streams throughout the watershed were 

0.01 milligram per liter (mg/L) or less, and attainment of the 

CDPHE standard for aquatic-life protection was met for all 

sites. More than 50 percent of dissolved nitrate concentrations 

were reported as less than laboratory detection levels (censored). Median concentrations were highest in Yampa River 

subwatersheds 3 and 4. All sites with data for unfiltered nitrate 

were in attainment of CDPHE standards for drinking water or 

agricultural use. More than 60 percent of unfiltered total ammonia concentrations in stream samples were less than detection 

levels. Less than one percent of samples had concentrations 
Summary 89

that exceeded the CDPHE aquatic-life standard; these samples 

were collected during 1975 or 1976. Median concentrations 

of unfiltered total phosphorus were highest in Yampa River 

subwatersheds 1, 3, and 4. Total phosphorus concentrations 

greater than federal recommendations to control downstream 

eutrophication were detected in about 14 percent of samples 

collected from more than 29 sites. A statistically significant 

upward trend in unfiltered total phosphorus concentrations was 

identified for Yampa River at Steamboat Springs (site 153). This 

trend may reflect population growth and land-use changes that 

have occurred upstream from the site.

Many trace elements are essential nutrients required by 

biota in small amounts, but substantial concentrations of trace 

elements can be toxic to aquatic life and possibly to wildlife, 

livestock, and people. For UYRW stream sites, about twothirds of the concentration data for dissolved and total recoverable cadmium, lead, nickel, and silver; dissolved chromium, 

copper, selenium, and zinc; and total dissolved and recoverable mercury were less than detection levels. Concentrations 

greater than 1,000 micrograms per liter (μg/L) were detected 

for total recoverable aluminum, iron, manganese, and zinc, 

and dissolved iron, manganese, and strontium. Maximum concentrations of the various trace elements occurred in Yampa 

River subwatersheds 1, 2, 3, or 4 and seemed to depend on the 

lithology of the rocks underlying the subwatershed. Seasonal 

variation in concentrations was evident for total recoverable 

aluminum, copper, iron, and zinc. There was a statistically significant downward trend in total recoverable manganese at site 

153. Some sites were not in attainment of CDPHE aquatic-life 

or water-supply standards for dissolved copper, iron, manganese, and selenium and for total recoverable iron.

Concentrations of the bacterium E. coli in five stream 

samples collected from 1994 through 2003 exceeded the 

CDPHE recreation standard of 126 colonies per 100 milliliters. Exceedances could be due to recreational users of a 

stream, wildlife, and (or) livestock.

The amount and size of suspended sediment in water are 

affected by streamflow. In the UYRW, suspended-sediment 

concentrations typically were lowest from August through 

February when streamflow was lowest and higher during 

April or May. The highest concentrations were in streams with 

watersheds underlain by sedimentary rocks.

Water-quality data for Lake Elbert, Long Lake Reservoir, 

Stagecoach Reservoir, Steamboat Lake, and Elkhead Reservoir 

for various time periods were analyzed or summarized for this 

study. Water in Lake Elbert and Long Lake Reservoir was very 

dilute; all values for specific conductance from 1985 through 

2005 (Long Lake Reservoir) or through 2009 (Lake Elbert) 

were 34 μS/cm or less. The reservoirs have little capacity to 

neutralize inputs of acidic water. Exceedances of CDPHE 

standards for pH and dissolved iron and manganese were 

rare and only occurred on as many as 5 sample days for Long 

Lake Reservoir. Stagecoach Reservoir and Steamboat Lake 

were vertically stratified during July 2006. Dissolved oxygen 

concentrations less than 0.5 mg/L at depth indicate anoxic 

conditions. Measurements of dissolved oxygen in Elkhead 

Reservoir from July 1995 through August 2001 indicate 

anoxic conditions were present in the reservoir at times during stratification. Trophic status of the reservoir ranged from 

oligotrophic to eutrophic; phosphorus was the limiting nutrient 

in more samples (52 percent) than nitrogen (9 percent).

A total of 816 groundwater-quality samples collected 

from 328 wells during 1975 through 1989 and 1998 were 

analyzed for this study. The sampled wells are concentrated 

in the middle latitudes of the watershed. About 66 percent of 

the wells with water-quality data were sampled only once. 

Samples were collected most often during 1975, 1978, and 

1988. Analysis of groundwater data focuses on one sample 

per day for physical properties, dissolved solids, major ions, 

nutrients, and trace elements. Data indicate that these wells 

tap aquifers in 12 geologic units, most often the flood-plain 

alluvium and Mesaverde Group. Well-construction information was not available for about 30 percent of wells. Wells 

without this information are grouped for this study as tapping 

“unknown geologic units.” More groundwater samples were 

collected from wells completed in the unknown geologic units, 

Mesaverde Group, and terrace alluvium than from wells completed in the other geologic units.

Analysis of physical-property data for groundwater 

indicates that specific conductance was lower in samples collected from igneous and metamorphic rocks and sedimentary 

rocks of nonmarine origin than sedimentary rocks of marine 

or marine-nonmarine origin. Values of pH less than the lower 

bound of the CDPHE secondary maximum contaminant level 

(SMCL) for groundwater were not as common as values 

greater than the upper bound. Samples with pH values not 

meeting the standard were most commonly collected from 

the flood-plain alluvium (values less than 6.5) and unknown 

geologic units (values greater than 8.5). The acid neutralizing 

capacity of water in samples from the sedimentary rock units 

indicate that water in these rock units is well buffered.

Median dissolved solids concentrations were lowest 

for samples collected from valley-fill deposits and highest 

for samples collected from the Mesaverde Group. Dominant 

cations were calcium and (or) calcium plus magnesium of a 

mixture of these with sodium. Bicarbonate was the dominant 

anion, but many samples also had sulfate. Median dissolved 

sulfate concentrations were lowest in samples collected from 

the Browns Park Formation and highest in samples collected 

from the terrace alluvium. About one-half of the dissolved 

sulfate samples had concentrations that were greater than the 

CDPHE SMCL. Exceedances were most common for samples 

collected from wells in the terrace alluvium, Mesaverde 

Group, and unknown geologic units.

All dissolved nitrite concentrations in groundwater samples were well below CDPHE maximum contaminant level 

(MCL). Median concentrations of dissolved nitrate pus nitrite 

for all geologic units were 1.5 mg/L or less. About 4.5 percent 
90 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

of samples had concentrations greater than the CDPHE MCL 

for nitrate. Almost all dissolved and unfiltered total phosphorus concentrations were less than 0.1 mg/L.

Concentrations of many trace elements in groundwater 

samples were low; more than 80 percent of the samples collected for dissolved antimony, arsenic, beryllium, cadmium, 

chromium, cobalt, copper, lead, mercury, molybdenum, nickel, 

selenium, and silver had concentrations less than or equal to 

laboratory detection levels. All concentrations of dissolved 

antimony, barium, chromium, cobalt, mercury, nickel, and 

silver met CDPHE human-health (HH) standards, MCLs, 

SMCL, and (or) agricultural-use standards for groundwater. 

Only one or two groundwater samples each had concentrations 

of dissolved arsenic, beryllium, copper, lead, molybdenum, 

and selenium that exceeded CDPHE HH standards, MCLs, 

SMCL, and (or) agricultural-use standards. Concentrations 

of dissolved cadmium greater than the CDPHE MCL were 

detected in less than 4 percent of samples. All samples but one 

were from wells in the Yampa coal field.

The highest trace element concentrations (3,600 μg/L or 

more) in groundwater were detected for dissolved aluminum 

and boron, dissolved and total recoverable iron, and dissolved 

manganese, strontium, and zinc. All dissolved aluminum concentrations were less than the CDPHE agricultural-use standard for livestock watering. The agricultural-use standard for 

dissolved boron was exceeded in about 13 percent of samples, 

most commonly for the terrace alluvium. All zinc concentrations 

were less than the CDPHE SMCL; fewer than one percent of 

samples had zinc concentrations that exceeded the agriculturaluse standard. Standards have not been established for dissolved 

strontium and total recoverable iron in groundwater.

Median concentrations of dissolved iron in geologic units 

with more than one sample were lowest for samples collected 

from the Browns Park Formation and highest for samples 

collected from valley-fill deposits. Concentrations of dissolved iron exceeded the CDPHE SMCL in about 10 percent 

of samples, most commonly those collected from valley-fill 

deposits and the Mancos Shale. Only three samples, two collected from the Mesaverde Group and one collected from an 

unknown geologic unit, had a dissolved-iron concentration 

that exceeded the CDPHE agricultural-use standard. Elevated 

concentrations (greater than 10,000 μg/L) of total recoverable 

iron were detected in samples from wells located in the Yampa 

coal field. Reducing conditions in the subsurface in the coal 

field area could be causing the high concentrations of iron.

The most exceedances of a CDPHE standard for trace 

elements in groundwater were for dissolved manganese; more 

than one-half of the samples had concentrations that exceeded 

the SMCL for groundwater. These samples were most commonly collected from the terrace alluvium, Mesaverde Group, 

and unknown geologic units. More than one-half of the 

exceedances were for wells in the Yampa coal field. About 

26 percent of groundwater samples also had dissolved manganese concentrations that exceeded the CDPHE agriculturaluse standard.

Macroinvertebrate community and population data were 

available for 66 stream sites in the UYRW for various periods 

of time between 1975 and 2008. A summary of results from 

one study of Yampa River sites in Steamboat Springs indicates 

that species tolerant of organic pollutants were more common 

at downstream sites than at upstream sites. However, changes 

observed in community characteristics between 2005 and 

2008 may be due to upstream effects or large-scale environmental factors rather than changes in water quality within the 

stream reach.

Synthesis of water-quality data indicates that the values 

and concentrations of many physical properties and constituents in surface-water samples for the UYRW are likely 

controlled primarily by geology, streamflow, and land use. The 

quality of groundwater in the UYRW is a function of various 

physical and geochemical processes, including precipitation, 

the depositional environment of the aquifer sediments, type 

of sediments that groundwater moves through, dissolution of 

soluble minerals in rocks and soils, and ion-exchange reactions. Constituents that are issues of concern for aquatic life, 

human health, or suitability of water for various uses include 

those on the CDPHE 2012 303(d) list of impaired waters or 

monitoring or evaluation list for surface water. Other constituents in stream water or groundwater that are or could be issues 

of concern include those that commonly have concentrations 

that exceed standards or that could affect technical qualities 

of water. This could include unfiltered sulfate, unfiltered total 

phosphorus, and dissolved copper in stream water; pH, unfiltered nitrate plus nitrite, and dissolved copper in groundwater; 

and hardness, dissolved solids, iron, and manganese in stream 

water and groundwater. Analysis of stream-water and groundwater data for changes in water quality over time was limited 

because of the absence of long-term data collection in the 

UYRW. Consistent long-term data collection of many years is 

needed at key sites for temporal trend analysis of water-quality 

data and to identify emerging changes in water quality.

Acknowledgments

The authors thank Judith Thomas for her assistance 

with compilation of water-quality data into the UYRW 

water-quality database, and Barbara C. Ruddy for her work 

in preparing the land cover and geology maps for this report. 

Technical assistance was provided by Kenneth J. Leib and 

David K. Mueller. Technical reviews were provided by 

Peter B. McMahon, Allan D. Druliner, and Lisa D. Miller. 

Editorial review was provided by Ruth Larkin. Manuscript 

preparation was provided by Joy Monson, Loretta Ulibarri, 

and Carol Wilkinson. All of the personnel identified above are 

USGS employees.
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Appendix 1 95

Appendix 1. U.S. Environmental Protection Agency STORET edit-checking procedure of low and high values for selected 

water-quality properties and constituents from the Upper Yampa River watershed water-quality database.—Continued

[°C, degrees Celsius; μS/cm, microsiemens per centimeter at 25 degrees Celsius; mg/L, milligrams per liter; CaCO3, calcium carbonate; HCO3

–

, 

bicarbonate; N, nitrogen; PO4, phosphate; P, phosphorus; μg/L, micrograms per liter; m-FC, membrane-Fecal Coliform; col/100 mL, colonies per 

100 milliliters; NO3, nitrate. Data are from National Park Service (2001)]

Parameter

code1

Parameter code name for 

water-quality property or constituent (reporting units)1

Low

value

High

value

P00010 Water temperature (°C) –2 37.0

P00094 Specific conductance (μS/cm) 1.0 60,000.0

P00095 Specific conductance (μS/cm) 1.0 60,000.0

P00300 Oxygen, dissolved (mg/L) 0.0 30.0

P00400 pH (standard units) 0.9 12.0

P00403 pH, lab (standard units) 0.9 12.0

P00410 Alkalinity, total (mg/L as CaCO3) 0.0 1,000.0

P00440 Bicarbonate (mg/L as HCO3

–

) 0.0 450.0

P00600 Nitrogen, total (mg/L as N) 0.0 100.0

P00610 Ammonia, total (mg/L as N) 0.0 20.0

P00615 Nitrite, total (mg/L as N) 0.0 5.0

P00625 Ammonia plus organic nitrogen, total (mg/L as N) 0.0 50.0

P00630 Nitrite plus nitrate, total (mg/L as N) 0.0 55.0

P00650 Phosphate, total (mg/L as PO4) 0.0 30.0

P00665 Phosphorus, total (mg/L as P) 0.0 10.0

P00900 Hardness, total (mg/L as CaCO3) 0.0 5,000.0

P00915 Calcium, dissolved (mg/L) 0.0 1,000.0

P00925 Magnesium, dissolved (mg/L) 0.0 1,000.0

P00930 Sodium, dissolved (mg/L) 0.0 5,000.0

P00935 Potassium, dissolved (mg/L) 0.0 1,000.0

P00940 Chloride, dissolved (mg/L) 0.0 22,000.0

P00945 Sulfate, total (mg/L) 0.0 2,500.0

P00946 Sulfate, dissolved (mg/L) 0.0 2,500.0

P00950 Fluoride, dissolved (mg/L) 0.0 15.0

P00955 Silica, dissolved (mg/L) 0.0 2,000.0

P01000 Arsenic, dissolved (μg/L) 0.0 5,000.0

P01002 Arsenic, total (μg/L) 0.0 5,000.0

P01005 Barium, dissolved (μg/L) 0.0 2,000.0

P01007 Barium, total (μg/L) 0.0 2,000.0

P01010 Beryllium, dissolved (μg/L) 0.0 2,000.0

P01012 Beryllium, total (μg/L) 0.0 2,000.0

P01020 Boron, dissolved (μg/L) 0.0 5,000.0

P01022 Boron, total (μg/L) 0.0 5,000.0

P01025 Cadmium, dissolved (μg/L) 0.0 500.0

P01027 Cadmium, total (μg/L) 0.0 500.0

P01030 Chromium, dissolved (μg/L) 0.0 2,000.0

P01032 Chromium, hexavalent (μg/L) 0.0 2,000.0

P01034 Chromium, total (μg/L) 0.0 2,000.0

P01040 Copper, dissolved (μg/L) 0.0 2,000.0

P01042 Copper, total (μg/L) 0.0 5,000.0

P01045 Iron, total (μg/L) 0.0 56,000.0

P01046 Iron, dissolved (μg/L) 0.0 56,000.0

P01049 Lead, dissolved (μg/L) 0.0 1,000.0

P01051 Lead, total (μg/L) 0.0 1,000.0
96 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Appendix 1. U.S. Environmental Protection Agency STORET edit-checking procedure of low and high values for selected 

water-quality properties and constituents from the Upper Yampa River watershed water-quality database.—Continued

[°C, degrees Celsius; μS/cm, microsiemens per centimeter at 25 degrees Celsius; mg/L, milligrams per liter; CaCO3, calcium carbonate; HCO3

–

, 

bicarbonate; N, nitrogen; PO4, phosphate; P, phosphorus; μg/L, micrograms per liter; m-FC, membrane-Fecal Coliform; col/100 mL, colonies per 

100 milliliters; NO3, nitrate. Data are from National Park Service (2001)]

Parameter

code1

Parameter code name for 

water-quality property or constituent (reporting units)1

Low

value

High

value

P01055 Manganese, total (μg/L) 0.0 5,000.0

P01056 Manganese, dissolved (μg/L) 0.0 5,000.0

P01065 Nickel, dissolved (μg/L) 0.0 2,000.0

P01067 Nickel, total (μg/L) 0.0 2,000.0

P01075 Silver, dissolved (μg/L) 0.0 5,000.0

P01077 Silver, total (μg/L) 0.0 5,000.0

P01090 Zinc, dissolved (μg/L) 0.0 25,000.0

P01092 Zinc, total (μg/L) 0.0 25,000.0

P01105 Aluminum, total (μg/L) 0.0 20,000.0

P01106 Aluminum, dissolved (μg/L) 0.0 20,000.0

P01145 Selenium, dissolved (μg/L) 0.0 100.0

P22703 Uranium, natural, dissolved (μg/L) 0.0 500.0

P31613 Fecal coliform, membrane filter, m-FC agar, 44.5 °C, 24 hour (col/100 mL) 0.0 10,000,000.0

P31616 Fecal coliform, membrane filter, m-FC broth (col/100 mL) 0.0 10,000,000.0

P70300 Residue, total filtrable, dried at 180 °C (mg/L) 0.0 4,000.0

P70507 Phosphorus, orthophosphate, total (mg/L as P) 0.0 10.0

P71850 Nitrate nitrogen, total (mg/L as NO3) 0.0 65.0

P71890 Mercury, dissolved (μg/L) 0.0 10.0

P71900 Mercury, total (μg/L) 0.0 10.0 1

Parameter codes and parameter code names for water-quality properties or constituents are from the U.S. Geological Survey National Water 

Information System (NWIS) and the U.S. Environmental Protection Agency Data STOrage and RETrieval System (STORET) Data Warehouse.
Appendix 2 97

Appendix 2. Selected Colorado Department of Public Health and Environment in-stream water-quality standards for stream segments in the Upper Yampa River watershed, Colorado.—Continued[mg/L, milligrams per liter; °C, degrees Celsius; DM, daily maximum temperature; MWAT, maximum weekly average temperature; SMCL, secondary maximum contaminant level; N, nitrogen; MCL; maximum contaminant level; TVS, table value standard; P, phosphorus; μg/L, micrograms per liter; tr, trout; FRV, Final Residue Value; sc, sculpin; CaCO3, calcium carbonate; ≥, greater than or equal to; col/100 mL, colonies per 100 milliliters. Water-quality standards are from Colorado Department of Public Health and Environment (2009a, 2010), unless otherwise stated. Descriptions of segments are in Colorado Department of Public Health and Environment (2010). Recommended total phosphorus levels are from U.S. Environmental Protection Agency (2000). Stream segments with no water-quality data in the Upper Yampa River watershed database or outside of the Upper Yampa River watershed boundary as defined for this report are not included in this table]

Physical property or constituent 

(units)

In-stream water-quality standard Stream segment Type Value1

Physical properties

pH (standard units) Aquatic life 6.5–9.0 allDissolved oxygen (mg/L) Aquatic life 6.0 1b, 2a–2c, 3–8, 11, 12, 13a–13c, 13f, 14, 20a

5.0 13d, 13e, 15

Water temperature 

(°C) (streams)

Aquatic life cold (June–Sept) 21.2 (acute, DM2) 2a, 3, 5, 6, 8, 11, 13a, 20a

17.0 (chronic, MWAT3)

Aquatic life cold (Oct–May) 13.0 (acute, DM2)

9.0 (chronic, MWAT3)

Aquatic life cold (Apr–Oct) 23.8 (acute, DM2) 2c, 4, 7, 12, 13b, 13c, 13f, 14

18.2 (chronic, MWAT3)

Aquatic life cold (Nov–Mar) 13.0 (acute, DM2)

9.0 (chronic, MWAT3)

Aquatic life warm (Mar–Nov) 28.6 (acute, DM2) 13d, 13e, 15

27.5 (chronic, MWAT3)

Aquatic life warm (Dec–Feb) 14.3 (acute, DM2)

13.7 (chronic, MWAT3)

Water temperature (°C) 

(lakes and reservoirs)

Aquatic life cold (Apr–Dec) 21.2 (acute, DM2) 1b, 2b

17.0 (chronic, MWAT3)

Aquatic life cold (Jan–Mar) 13.0 (acute, DM2)

9.0 (chronic, MWAT3)

Aquatic life cold (Apr–Dec) 23.8 (acute, DM2) 2b4,5

18.2 (chronic, MWAT3)

Aquatic life cold (Jan–Mar) 13.0 (acute, DM2)

9.0 (chronic, MWAT3)

Dissolved solids and major ions

Dissolved solids (mg/L) Water supply (SMCL)6 500 1b, 2a–2c, 3, 4, 6, 8, 13a, 13c (June–Feb), 13f, 14, 15, 20aSulfate, unfiltered (mg/L) Water supply (SMCL) 250 1b, 2a–2c, 3, 4, 6, 8, 13a, 13c (June–Feb), 13f, 14, 15, 20aChloride, unfiltered (mg/L) Water supply (SMCL) 250 1b, 2a– 2c, 3, 4, 6, 8, 13a, 13c (June–Feb), 13f, 14, 15, 20a

Nutrients

Nitrite, unfiltered (mg/L as N) Aquatic life 0.05 allNitrate, unfiltered (mg/L as N) Water supply (MCL) 10 1b, 2a–2c, 3, 4, 6, 8, 13a, 13c (June–Feb), 13f, 14, 15, 20a

Agriculture 100 5, 7, 11, 12, 13b, 13c (March–May), 13d, 13e

Total ammonia (mg/L as N) Aquatic life TVS (acute, chronic) or none 1b, 2a–2c, 3, 5–8, 13a–13f, 14, 15, 20aTotal phosphorus (mg/L as P) Recommended7 0.05 2a, 3, 15 (Streams that flow directly into lake or reservoir)

0.1 2a, 2c, 3, 4, 6, 8, 13a, 13c (June–Feb), 13f, 14, 15, 20a (Streams that do not flow 

directly into lake or reservoir)
98 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009 Appendix 2. Selected Colorado Department of Public Health and Environment in-stream water-quality standards for stream segments in the Upper Yampa River watershed, Colorado.—Continued [mg/L, milligrams per liter; °C, degrees Celsius; DM, daily maximum temperature; MWAT, maximum weekly average temperature; SMCL, secondary maximum contaminant level; N, nitrogen; MCL; maximum contaminant level; TVS, table value standard; P, phosphorus; μg/L, micrograms per liter; tr, trout; FRV, Final Residue Value; sc, sculpin; CaCO3, calcium carbonate; ≥, greater than or equal to; col/100 mL, colonies per 100 milliliters. Water-quality standards are from Colorado Department of Public Health and Environment (2009a, 2010), unless otherwise stated. Descriptions of segments are in Colorado Department of Public Health and Environment (2010). Recommended total phosphorus levels are from U.S. Environmental Protection Agency (2000). Stream segments with no water-quality data in the Upper Yampa River watershed database or outside of the Upper Yampa River watershed boundary as defined for this report are not included in this table] Physical property or constituent (units) In-stream water-quality standard Stream segment Type Value1 Trace elements Arsenic, dissolved (μg/L) Aquatic life 340 (acute) all Arsenic, total recoverable (μg/L) Aquatic life 0.02 (chronic) 1b, 2a–2c, 3, 6, 8, 13a, 13c (June–Feb), 13f, 14, 15, 20a 0.02–10 (chronic) 8

4

7.6 (chronic) 5, 7, 13b, 13c (March–May)

100 (chronic) 811, 12, 13d, 13e

Boron, dissolved (μg/L) Agriculture 750 allCadmium, dissolved (μg/L) Aquatic life TVS(tr) (acute) 1b, 2a–2c, 3, 5–8, 13a–3c, 13f, 14, 15, 20a

TVS (acute) 13d, 13e

TVS (chronic) 1b, 2a–2c, 3, 5–8, 13a–13f, 14, 15, 20a

Cadmium, total recoverable (μg/L) Aquatic life 5 (acute) 8

4

10 (chronic) 811, 12

Chromium, dissolved (μg/L) Aquatic life TVS (16 acute, 11 chronic) 1b, 2a–2c, 3, 5–8, 13a–13e, 14, 15, 20aChromium, total recoverable (μg/L) Aquatic life 50 (acute) 8

4

100 (chronic) 11, 12

Copper, dissolved (μg/L) Aquatic life TVS (acute, chronic) 1b, 2a–2c, 3, 5–8, 13a–13e, 14, 15, 20aCopper, total recoverable (μg/L) Aquatic life 200 (chronic) 8

4

200 (acute) 11, 12

Iron, dissolved (μg/L) Water supply (SMCL) 300 (chronic) 1b, 2a–2c, 3, 4, 6, 8, 13a, 13c (June–Feb), 13f, 14, 15, 20aIron, total recoverable (μg/L) Aquatic life 1,000 (chronic) 1b, 2a–2c, 3, 5–8, 13a, 13b (not Middle Creek), 13c, 13f, 14, 15, 20a

1,035 (chronic) 13b (Middle Creek)

existing quality (chronic) 13d, 13e

Lead, dissolved (μg/L) Aquatic life TVS (acute, chronic) 1b, 2a–2c, 3, 5–8, 13a–13e, 14, 15, 20aLead, total recoverable (μg/L) Aquatic life 50 (acute) 8

4

100 (chronic) 11, 12

Manganese, dissolved (μg/L) Aquatic life TVS (acute, chronic) 1b, 2a–2c, 3, 5–8, 13a–13f, 14, 15, 20a

Water supply (SMCL) 50 (chronic) 1b, 2a–2c, 3, 6, 8, 13a, 13c (June–Feb), 13f, 14, 15, 20a

Manganese, total recoverable 

(μg/L)

Aquatic life TVS (acute, chronic) 8

4

200 (chronic) 11, 12

Water supply (SMCL) 50 (chronic) 8

4

Mercury, total, dissolved (μg/L) FRV9 0.01 (chronic) 1b, 2a–2c, 3, 5–8, 13a–13e, 14, 15, 20aMercury, total recoverable (μg/L) Aquatic life 2.0 (acute) 4Nickel, dissolved (μg/L) Aquatic life TVS (acute, chronic) 1b, 2a–2c, 3, 5–8, 13a–13e, 14, 15, 20aNickel, total recoverable (μg/L) Aquatic life 100 (chronic) 8

4

200 (chronic) 11, 12

Selenium, dissolved (μg/L) Aquatic life TVS (18.4 acute, 4.6 chronic) 1b, 2a–2c, 3, 5–8, 13a–13e, 14, 15, 20a
Appendix 2 99

Appendix 2. Selected Colorado Department of Public Health and Environment in-stream water-quality standards for stream segments in the Upper Yampa River watershed, Colorado.—Continued[mg/L, milligrams per liter; °C, degrees Celsius; DM, daily maximum temperature; MWAT, maximum weekly average temperature; SMCL, secondary maximum contaminant level; N, nitrogen; MCL; maximum contaminant level; TVS, table value standard; P, phosphorus; μg/L, micrograms per liter; tr, trout; FRV, Final Residue Value; sc, sculpin; CaCO3, calcium carbonate; ≥, greater than or equal to; col/100 mL, colonies per 100 milliliters. Water-quality standards are from Colorado Department of Public Health and Environment (2009a, 2010), unless otherwise stated. Descriptions of segments are in Colorado Department of Public Health and Environment (2010). Recommended total phosphorus levels are from U.S. Environmental Protection Agency (2000). Stream segments with no water-quality data in the Upper Yampa River watershed database or outside of the Upper Yampa River watershed boundary as defined for this report are not included in this table]

Physical property or constituent 

(units)

In-stream water-quality standard Stream segment Type Value1

Trace elements—Continued

Silver, dissolved (μg/L) Aquatic life TVS (acute) 1b, 2a–2c, 3, 5–8, 13a–13f, 14, 15, 20a

TVS(tr) (chronic) 1b, 2a–2c, 3, 5–8, 13a–13c, 13f, 14, 15, 20a

TVS (chronic) 13d, 13e

Silver, total recoverable (μg/L) Aquatic life 100 (acute) 84Zinc, dissolved (μg/L) Aquatic life TVS (acute) 1b, 2a–2c, 3, 5–8, 13a–13f, 14, 15, 20a

TVS(sc) (chronic) 2a, 2c, 3, 8, 13a (hardness less than 113 mg/L CaCO3)

TVS (chronic) 1b, 2b, 5–7, 13b–13f, 14, 15, 20a; 2a, 2c, 3, 8, 13a (hardness ≥ 113 mg/L CaCO3)

Zinc, total recoverable (μg/L) Aquatic life 2,000 (acute) 84

2,000 (chronic) 104, 11, 12

Radiochemical

Uranium, natural, dissolved (μg/L) Water supply 1130 all

Coliform bacteria

Escherichia coli (col/100 mL) Recreation 12126/100 1b, 2a–2c, 3, 6, 8, 13a–13d, 13f, 14, 15, 20a

12205/100 85, 712630/100 84, 11, 12, 13e

1Table value standards for trace elements vary with hardness (Colorado Department of Public Health and Environment, 2009a, 2010).2Daily maximum temperature (DM) is the highest 2-hour average water temperature recorded during a given 24-hour period (Colorado Department of Public Health and Environment, 2009a).3Maximum weekly average temperature (MWAT) is the maximum average of multiple, equally spaced, daily temperatures over 7 consecutive days with a minimum of three data points spaced equally throughout 

the day (Colorado Department of Public Health and Environment, 2009a).

4Temperature standard applies to lakes and reservoirs with a surface area greater than or equal to 100 acres surface area (Colorado Department of Public Health and Environment, 2009a).5April–December temperature WAT (weekly average temperature) for stream segment 2b: Stagecoach Reservoir, 21.4 °C; Steamboat Lake, 21.6 °C (Colorado Department of Public Health and Environment, 2010).6For stream segments with dissolved solids data, the standard has been applied to stream segments that have standards for unfiltered sulfate and chloride.7For stream segments with total phosphorus data, the recommendation has been applied to stream segments that have a standard for unfiltered nitrate.8No data were available for the constituent of interest in the steam segment(s) listed.9Final residue value (FRV) is the maximum allowed concentration of total mercury in water that will present bioaccumulation or bioconcentration of methylmercury in edible fish tissue (Colorado Department of 

Public Health and Environment, 2009a).

10No data for total recoverable zinc were available for segment 4.11Uranium level in surface water used for water supply shall be maintained at the lowest practical level. The maximum allowed concentration in water used for supply is 30 micrograms per liter, unless naturally 

occurring concentrations are greater (Colorado Department of Public Health and Environment, 2009a).

12Attainment of the Colorado Department of Public Health and Environment water-quality standard is based on the geometric mean of the data. 
100 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Appendix 3. Description of selected stream sampling sites in the Upper Yampa River watershed, Colorado, with type of water-quality 

data collected, period of water-quality record, and number of samples collected, 1975 through 2009.—Continued

[No., number; USFS, U.S. Department of the Agriculture Forest Service; PP, physical properties; D, discharge; CB, coliform bacteria; SS, suspended sediment; 

CDPHE, Colorado Department of Public Health and Environment; DS, dissolved solids; MI, major ions; N, nutrients, TE, trace elements; CODOW, Colorado 

Division of Wildlife Riverwatch Program; USGS, U.S. Geological Survey; DOC, dissolved organic carbon; CSS, City of Steamboat Springs; U, uranium; USEPA, 

U.S. Environmental Protection Agency. Subwatershed definitions: Yampa River subwatershed 1, Yampa River and tributaries upstream from Chuck Lewis State 

Wildlife Area; Yampa River subwatershed 2, Yampa River and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence; Elk River subwatershed, 

Elk River and tributaries; Yampa River subwatershed 3, Yampa River and tributaries from Elk River confluence to Town of Hayden; Yampa River subwatershed 4, 

Yampa River and tributaries from Town of Hayden to Elkhead Creek confluence; Elkhead Creek subwatershed, Elkhead Creek and tributaries. Sites with the same 

site number are considered to be at the same location. Sites with name in bold are streamgage stations; see table 1 for additional information on these sites. The 

Upper Yampa River water-quality database is available at http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml]

Site no.

(see figure 3) Site name in Upper Yampa River watershed water-quality database Sourceof data

Site

identifier Latitude

1 BEAR R. #2 13 MI SW YAMPA USFS 11057702 40.05

2 BEAR R. #3 10MI SW YAMPA USFS 11057703 40.067

3 BEAR R. @ RD. 8 CDPHE 12898 40.157

4 BEAR RIVER #1 USFS 11057701 40.033

5 Bear River Miller CODOW CDOWRW-6 40.08

6 BEAR RIVER NEAR TOPONAS, CO USGS 09236000 40.044

7 BEAVER CREEK NEAR HAHNS PEAK, CO. USGS 404610106545600 40.769

8 BTKN-DWN [Butcherknife Creek 15m above Yampa St] CSS BTKN-DWN 40.484

9 BURGESS C TRIB BL SKI AREA NR STEAMBOAT SPGS, CO USGS 402745106473600 40.462

10 BURGESS CK NEAR MOUTH @ HWY 40 CDPHE 12893 40.452

11 BURGESS CREEK AB SKI AREA NR STEAMBOAT SPGS, CO. USGS 402802106471000 40.467

12 BURGESS CREEK BL SKI AREA NR STEAMBOAT SPGS, CO. USGS 402720106481500 40.456

13 BUTCHERKNIFE CREEK NR MOUTH AT STEAMBOAT SPG,CO. USGS 402944106495900 40.496

14 CHENEY CREEK NEAR MILNER,CO. USGS 402908107014000 40.486

15 CHIMNEY CK @ RD. 8 CDPHE 12899 40.158

16 CHIMNEY CREEK AT TRAPPER, CO. USGS 400612106524800 40.103

17 COW CR. NR. STEAMBOAT SPRINGS,CO. USGS 402836106550100 40.477

18 CREEK ROUTT USGS 403333106504900 40.559

19 DEEP CREEK AT HAHNS PEAK, CO. USGS 404845106571400 40.812

20 DILL GULCH NEAR HAYDEN, CO USGS 402605107181500 40.435

21 DILL GULCH TRIBUTARY 0.2MI AB MOUTH -S132 USGS 402558107182101 40.433

22 DRY CK @ HAYDEN CDPHE 12852 40.492

22 DRY CREEK AT HWY 40 AT HAYDEN, CO USGS 402938107160101 40.494

23 DRY CK AT HAYDEN NR YAMPA VALLEY AIRPORT CDPHE 12852A 40.481

24 DRY CREEK ABOVE SEWAGE PLANT AT HAYDEN, CO. USGS 402939107160100 40.494

25 DRY CREEK BELOW SEWAGE PLANT AT HAYDEN, CO. USGS 402952107161600 40.498

26 ELK R.@ RD. 64A CDPHE 12868 40.752

27 ELK R. NEAR MOUTH @ CR44 CDPHE 12860 40.546

28 ELK RIVER AB. GLEN EDEN CDPHE 12865 40.716

29 ELK RIVER ABOVE CLARK, CO USGS 09240900 40.743

30 ELK RIVER AT CLARK, CO. USGS 09241000 40.717

31 ELK RIVER BELOW SOUTH FORK AT HINMAN PARK, CO. USGS 404506106492800 40.752

32 ELK RIVER NEAR MILNER CDPHE 000154 40.483

33 ELK RIVER NEAR MILNER, CO. USGS 09242500 40.515

33 ELK R. @ RD. 42 CDPHE 12861 40.515

34 ELK RIVER NEAR MOUTH USGS 402914106580400 40.487

34 ELK RIVER NEAR MOUTH AT US 40 BRIDGE, CO. USGS 402913106580400 40.487

35 ELKHEAD CR 1.5 MILES BELOW NORTH FORK CDPHE ELKHEAD03 40.65

36 ELKHEAD CR AT HWY 40 BRIDGE CDPHE ELKHEAD01 40.667

37 ELKHEAD CR BELOW ELKHEAD RES CDPHE ELKHEAD02 40.55

38 ELKHEAD CREEK USEPA WCOP99-0512 40.660

39 ELKHEAD CREEK USEPA WCOP99-0565 40.620

40 ELKHEAD CREEK ABOVE LONG GULCH, NEAR HAYDEN, CO USGS 09246200 40.592

40 ELKHEAD CREEK ABOVE ELKHEAD RESERVOIR, CO. USGS 403530107191300 40.592

41 ELKHEAD CREEK BELOW ELKHEAD RESERVOIR, CO USGS 403318107230100 40.555

42 ELKHEAD CREEK BELOW MAYNARD GULCH, NEAR CRAIG, CO USGS 09246400 40.545

43 ELKHEAD CREEK NEAR CRAIG, CO USGS 09246500 40.531

43 ELKHEAD CK NR CRAIG @ HWY 40 CDPHE 12840 40.531

43 ELKHEAD CREEK NEAR MOUTH USGS 403152107260700 40.531
Appendix 3 101

Appendix 3. Description of selected stream sampling sites in the Upper Yampa River watershed, Colorado, with type of water-quality 

data collected, period of water-quality record, and number of samples collected, 1975 through 2009.—Continued

[No., number; USFS, U.S. Department of the Agriculture Forest Service; PP, physical properties; D, discharge; CB, coliform bacteria; SS, suspended sediment; 

CDPHE, Colorado Department of Public Health and Environment; DS, dissolved solids; MI, major ions; N, nutrients, TE, trace elements; CODOW, Colorado 

Division of Wildlife Riverwatch Program; USGS, U.S. Geological Survey; DOC, dissolved organic carbon; CSS, City of Steamboat Springs; U, uranium; USEPA, 

U.S. Environmental Protection Agency. Subwatershed definitions: Yampa River subwatershed 1, Yampa River and tributaries upstream from Chuck Lewis State 

Wildlife Area; Yampa River subwatershed 2, Yampa River and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence; Elk River subwatershed, 

Elk River and tributaries; Yampa River subwatershed 3, Yampa River and tributaries from Elk River confluence to Town of Hayden; Yampa River subwatershed 4, 

Yampa River and tributaries from Town of Hayden to Elkhead Creek confluence; Elkhead Creek subwatershed, Elkhead Creek and tributaries. Sites with the same 

site number are considered to be at the same location. Sites with name in bold are streamgage stations; see table 1 for additional information on these sites. The 

Upper Yampa River water-quality database is available at http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml]

Site no.

(see figure 3) Longitude Subwatershed Type of water-quality data collected1

Period of waterquality record

(calendar year)

No. of

samples

1 –107.067 Yampa River subwatershed 1 PP,D,CB,SS 1975 6

2 –107.033 Yampa River subwatershed 1 PP,D,CB,SS 1975, 1978–79 24

3 –106.902 Yampa River subwatershed 1 PP,D,DS,MI,N,TE 2

2000–07 9

4 –107.117 Yampa River subwatershed 1 PP,CB,SS 1975 5

5 –106.97 Yampa River subwatershed 1 PP,D,TE 1990–99 131

6 –107.072 Yampa River subwatershed 1 PP,D,N,TE,DOC 2

1975–86, 2005 46

7 –106.916 Elk River subwatershed PP,D,N,TE,DOC 1975 1

8 –106.834 Yampa River subwatershed 2 PP,MI,N,TE,CB 2007–08 4

9 –106.794 Yampa River subwatershed 2 PP,D,N 1976 3

10 –106.810 Yampa River subwatershed 2 PP,D,DS,MI,N,TE,CB 1999 1

11 –106.787 Yampa River subwatershed 2 PP,D,N,CB,SS 1975–76 8

12 –106.805 Yampa River subwatershed 2 PP,D,CB,SS 1975–76 5

13 –106.821 Yampa River subwatershed 2 PP,D,N,CB 1975–76 5

14 –107.028 Yampa River subwatershed 3 D,CB 1975 1

15 –106.9 Yampa River subwatershed 1 PP,DS,MI,N,TE 2

2001–07 17

16 –106.881 Yampa River subwatershed 1 PP,D,DS,MI,N,TE,DOC,CB,SS 1975–76 6

17 –106.918 Yampa River subwatershed 2 PP,D,DS,MI,N,TE,SS 1981–82, 2005 10

18 –106.848 Yampa River subwatershed 2 PP,MI,TE 1976 1

19 –106.954 Elk River subwatershed PP,D,N,TE,DOC 1975 1

20 –107.305 Yampa River subwatershed 4 PP,D,DS,MI,N,TE,SS 1981–82 4

21 –107.306 Yampa River subwatershed 4 PP,D,DS,MI,N,TE 1982 1

22 –107.265 Yampa River subwatershed 4 PP,DS,MI,N,TE,U,CB 2

2001–05 7

22 –107.267 Yampa River subwatershed 4 PP,D 2005 2

23 –107.236 Yampa River subwatershed 4 PP,MI,N,TE 2007 2

24 –107.268 Yampa River subwatershed 4 PP 1975 2

25 –107.272 Yampa River subwatershed 4 PP,D,N,CB 1975 4

26 –106.759 Elk River subwatershed PP,DS,MI,N,TE,CB 2001–02 13

27 –106.909 Elk River subwatershed PP,DS,MI,N,TE 1999 1

28 –106.916 Elk River subwatershed PP,DS,MI,N,TE 1996–97 11

29 –106.855 Elk River subwatershed PP,D 2

1987–2003 99

30 –106.916 Elk River subwatershed PP,D,DS,MI,N,TE,DOC,SS 2

1975–2003 148

31 –106.825 Elk River subwatershed PP,D,DS,MI,N,TE,DOC,CB,SS 1975–76 6

32 –106.979 Elk River subwatershed PP,DS,MI,N,TE,U 1979–82 21

33 –106.954 Elk River subwatershed PP,D,DS,MI,N,TE,DOC,CB,SS 1975–76, 1989–2005 180

33 –106.954 Elk River subwatershed PP,DS,MI,N,TE,U,CB 2

2001–07 25

34 –106.968 Elk River subwatershed PP,D,DS,MI,N,DOC 1999–2000 2

34 –106.968 Elk River subwatershed PP,N,CB 1975 2

35 –107.317 Elkhead Creek subwatershed PP,DS 1979 1

36 –107.283 Elkhead Creek subwatershed PP,DS,TE 1979 1

37 –107.383 Elkhead Creek subwatershed PP,TE 1979 1

38 –107.291 Elkhead Creek subwatershed PP,MI,N,TE,DOC 2000 2

39 –107.271 Elkhead Creek subwatershed PP,MI,N,TE,DOC 2001 2

40 –107.321 Elkhead Creek subwatershed PP,D,DS,MI,N,TE,DOC,CB,SS 1995–2004 143

40 –107.321 Elkhead Creek subwatershed PP,D,DS,MI,N,TE,DOC,CB,SS 2

1975–83 10

41 –107.384 Elkhead Creek subwatershed PP,D,SS 2

1997–2003 10

42 –107.398 Elkhead Creek subwatershed PP,D,DS,MI,N,TE,DOC,CB,SS 1995–2005 143

43 –107.436 Elkhead Creek subwatershed PP,D,DS,MI,N,TE,DOC,SS 2

1975–83, 2005 9

43 –107.436 Elkhead Creek subwatershed PP,DS,MI,N,TE,CB 2

1999–2007 19

43 –107.436 Elkhead Creek subwatershed PP,D,DS,MI,N,DOC 1999 1
102 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Appendix 3. Description of selected stream sampling sites in the Upper Yampa River watershed, Colorado, with type of water-quality 

data collected, period of water-quality record, and number of samples collected, 1975 through 2009.—Continued

[No., number; USFS, U.S. Department of the Agriculture Forest Service; PP, physical properties; D, discharge; CB, coliform bacteria; SS, suspended sediment; 

CDPHE, Colorado Department of Public Health and Environment; DS, dissolved solids; MI, major ions; N, nutrients, TE, trace elements; CODOW, Colorado 

Division of Wildlife Riverwatch Program; USGS, U.S. Geological Survey; DOC, dissolved organic carbon; CSS, City of Steamboat Springs; U, uranium; USEPA, 

U.S. Environmental Protection Agency. Subwatershed definitions: Yampa River subwatershed 1, Yampa River and tributaries upstream from Chuck Lewis State 

Wildlife Area; Yampa River subwatershed 2, Yampa River and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence; Elk River subwatershed, 

Elk River and tributaries; Yampa River subwatershed 3, Yampa River and tributaries from Elk River confluence to Town of Hayden; Yampa River subwatershed 4, 

Yampa River and tributaries from Town of Hayden to Elkhead Creek confluence; Elkhead Creek subwatershed, Elkhead Creek and tributaries. Sites with the same 

site number are considered to be at the same location. Sites with name in bold are streamgage stations; see table 1 for additional information on these sites. The 

Upper Yampa River water-quality database is available at http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml]

Site no.

(see figure 3) Site name in Upper Yampa River watershed water-quality database Sourceof data

Site

identifier Latitude

44 ELKHEAD CREEK NEAR ELKHEAD, CO. USGS 09245000 40.670

45 ENGLISH CREEK ABOVE MOUTH, NEAR CLARK, CO USGS 404727106453700 40.791

46 FISH [Fish Creek below Hwy 40 and 10m above pedestrian bridge] CSS FISH 40.466

47 FISH C TRIB BL LONG LK, NR BUFFLAO PASS, CO. USGS 09238710 40.477

48 FISH CK @ RD. 27 CDPHE 12854 40.356

49 FISH CR AT UPPER STA NR STEAMBOAT SPRINGS, CO USGS 09238900 40.475

49 FISH CK AT STEAMBOAT CDPHE 12874 40.475

50 FISH CR TRIB AB LONG LK, NR BUFFALO PASS, CO. USGS 09238700 40.473

51 FISH CREEK AT MOUTH NEAR MILNER, CO. USGS 402530106585700 40.425

51 FISH CREEK AT ROAD 179 CDPHE 12854A 40.423

52 FISH CREEK NEAR MILNER, CO. USGS 09244100 40.334

53 FISH CREEK NEAR STEAMBOAT SPRINGS, CO USGS 09239000 40.465

54 FISH CREEK NR MOUTH AT STEAMBOAT SPRINGS, CO. USGS 402759106493100 40.466

54 FISH CK NEAR MOUTH @ HWY 40 CDPHE 12870 40.467

55 FOIDEL CREEK AT MOUTH NEAR OAK CREEK, CO USGS 09243900 40.390

55 FOIDEL CK @ RD. 33 CDPHE 12856 40.390

56 FOIDEL CREEK NEAR OAK CREEK, CO USGS 09243800 40.346

57 GRANITE C NR BUFFALO PASS, CO. USGS 09238770 40.493

58 GRASSY CREEK AT GRASSY GAP, CO. USGS 402330107082000 40.392

59 GRASSY CREEK NEAR MOUNT HARRIS, CO. USGS 09244300 40.447

59 GRASSY CK @ RD. 27A CDPHE 12853 40.447

60 HARRISON CREEK AT MOUTH NR BLACKTAIL MTN, CO. USGS 402056106471600 40.349

61 HUBBERSON GULCH NEAR HAYDEN, CO. USGS 09244464 40.391

62 L. MORRISON C AB DAM SITE NR OAK CREEK, CO USGS 401540106502801 40.261

63 LITTLE MORRISON CK @ RD 18A CDPHE 12896 40.273

64 LITTLE MORRISON CREEK @ CR 16 CDPHE 12896A 40.271

65 LITTLE MORRISON CREEK NEAR STAGECOACH, CO. USGS 401634106502200 40.276

66 LITTLE WHITE SNAKE CK @ HWY 131 CDPHE 12897 40.241

67 LONG LAKE INLET NEAR BUFFALO PASS, CO. USGS 09238705 40.474

68 LOST DOG CREEK ABOVE MOUTH, NEAR CLARK, CO USGS 404750106454200 40.797

69 MAD CREEK NEAR STEAMBOAT SPRINGS, CO. USGS 09242000 40.566

69 MAD CK @ CHRISTINA SWA CDPHE 12863 40.565

70 MARTIN C AB DAM SITE NR OAK CREEK, CO USGS 401729106514601 40.291

71 MD FK FISH C NR BUFFALO PASS, CO. USGS 09238750 40.498

72 MID FK FISH CR TRIB BL FISH CR RESERVOIR, CO USGS 09238800 40.497

73 MIDDLE C AB DAM SITE NR OAK CREEK, CO USGS 401608106513001 40.269

73 MIDDLE CREEK @ CR 16 CDPHE 12809B 40.269

74 MIDDLE CK., SAMPLE #7 USGS 402354106584400 40.398

74 MIDDLE CK @ 33 RD. CDPHE 12855 40.397

75 MIDDLE CREEK NEAR OAK CREEK, CO USGS 09243700 40.386

76 NORTH FORK ELK RIVER ABOVE MOUTH, NEAR CLARK, CO USGS 404620106461900 40.772

76 NORTH FORK ELK RIVER NEAR HINMAN PARK, CO. USGS 404620106462200 40.772

77 NORTH FORK ELK RIVER ABV AGNES CREEK, NR CLARK, CO USGS 405057106451000 40.849

78 NORTH FORK ELK RIVER ABV TRAIL CREEK, NR CLARK, CO USGS 404950106462700 40.831

79 NORTH FORK ELKHEAD CREEK NEAR ELKHEAD, CO. USGS 09245500 40.681

80 NORTH FORK OF FOIDEL CREEK AT MOUTH, CO USGS 402007107050400 40.335

81 NORTH FORK WALTON CREEK NR RABBIT EARS PASS, CO. USGS 09238300 40.396

82 OAK CR AT NAT FOREST BOUNDARY ABOVE TOWN CDPHE OAK01 40.217
Appendix 3 103

Appendix 3. Description of selected stream sampling sites in the Upper Yampa River watershed, Colorado, with type of water-quality 

data collected, period of water-quality record, and number of samples collected, 1975 through 2009.—Continued

[No., number; USFS, U.S. Department of the Agriculture Forest Service; PP, physical properties; D, discharge; CB, coliform bacteria; SS, suspended sediment; 

CDPHE, Colorado Department of Public Health and Environment; DS, dissolved solids; MI, major ions; N, nutrients, TE, trace elements; CODOW, Colorado 

Division of Wildlife Riverwatch Program; USGS, U.S. Geological Survey; DOC, dissolved organic carbon; CSS, City of Steamboat Springs; U, uranium; USEPA, 

U.S. Environmental Protection Agency. Subwatershed definitions: Yampa River subwatershed 1, Yampa River and tributaries upstream from Chuck Lewis State 

Wildlife Area; Yampa River subwatershed 2, Yampa River and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence; Elk River subwatershed, 

Elk River and tributaries; Yampa River subwatershed 3, Yampa River and tributaries from Elk River confluence to Town of Hayden; Yampa River subwatershed 4, 

Yampa River and tributaries from Town of Hayden to Elkhead Creek confluence; Elkhead Creek subwatershed, Elkhead Creek and tributaries. Sites with the same 

site number are considered to be at the same location. Sites with name in bold are streamgage stations; see table 1 for additional information on these sites. The 

Upper Yampa River water-quality database is available at http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml]

Site no.

(see figure 3) Longitude Subwatershed Type of water-quality data collected1

Period of waterquality record

(calendar year)

No. of

samples

44 –107.285 Elkhead Creek subwatershed PP,D,DS,MI,N,TE,DOC,CB,SS 3

1975–96 141

45 –106.761 Elk River subwatershed PP,D,DS,MI,N,TE,DOC,SS 2

1999–2003 14

46 –106.829 Yampa River subwatershed 2 PP,MI,N,TE,CB 2007–08 4

47 –106.688 Yampa River subwatershed 2 PP,D,DS,MI,N,SS 1985–95 40

48 –107.104 Yampa River subwatershed 3 PP,DS,MI,N,TE,CB 2001 4

49 –106.787 Yampa River subwatershed 2 PP,D,DS,MI,N,TE,CB,SS 1982–2004 166

49 –106.783 Yampa River subwatershed 2 PP,DS,MI,N,TE 1996–97 10

50 –106.680 Yampa River subwatershed 2 PP,D 1985–87 8

51 –106.983 Yampa River subwatershed 3 PP,D,DS,MI,N,TE,DOC,SS 2

1975–82, 2005 16

51 –106.986 Yampa River subwatershed 3 PP,MI,N,TE 2006–07 4

52 –107.139 Yampa River subwatershed 3 PP,D,DS,MI,N,TE,DOC,SS 2

1975–82, 2005 18

53 –106.821 Yampa River subwatershed 2 PP,D,N,CB,SS 1975–76 8

54 –106.826 Yampa River subwatershed 2 PP,D,N,CB 1975, 2005 4

54 –106.825 Yampa River subwatershed 2 PP,D,DS,MI,N,TE,CB 2

1999–2002 5

55 –106.995 Yampa River subwatershed 3 PP,D,DS,MI,N,TE,DOC,SS 1975–2001, 2005 290

55 –106.996 Yampa River subwatershed 3 PP,DS,MI,N,TE,CB 2

2001–07 7

56 –107.085 Yampa River subwatershed 3 PP,D,DS,MI,N,TE,DOC,SS 4

1975–2001 226

57 –106.693 Yampa River subwatershed 2 PP,D,MI,N,SS 1985–95 65

58 –107.139 Yampa River subwatershed 3 PP,D,DS,MI,N,TE,DOC,SS 2

1975–82 22

59 –107.146 Yampa River subwatershed 3 PP,D,DS,MI,N,TE,DOC,SS 2

1975–82 21

59 –107.146 Yampa River subwatershed 3 PP,DS,MI,N,TE,U,CB 2

2001–07 7

60 –106.788 Yampa River subwatershed 1 PP,D,CB,SS 1975–76 4

61 –107.271 Yampa River subwatershed 4 PP,D,DS,MI,N,TE,DOC,SS 1978–82 41

62 –106.842 Yampa River subwatershed 1 PP,D,SS 1986–88 17

63 –106.839 Yampa River subwatershed 1 PP,DS,MI,N,TE 2

2001–07 7

64 –106.839 Yampa River subwatershed 1 PP,D,DS,MI,N,TE 2000 1

65 –106.840 Yampa River subwatershed 1 PP,D,N,CB,SS 1975–76 5

66 –106.943 Yampa River subwatershed 1 PP,DS,MI,N,TE 2

2001–07 4

67 –106.680 Yampa River subwatershed 2 PP,D,MI,N,SS 1986–95 51

68 –106.762 Elk River subwatershed PP,D,DS,MI,N,TE,U,DOC,SS 2

1999–2006 21

69 –106.889 Elk River subwatershed PP,D,DS,MI,N,TE,DOC,CB,SS 1975–76, 2003 12

69 –106.889 Elk River subwatershed PP,DS,MI,N,TE 1996–98, 2006–07 16

70 –106.863 Yampa River subwatershed 1 PP,D,SS 1986–88 17

71 –106.692 Yampa River subwatershed 2 PP,D,MI,N,SS 1985–95 61

72 –106.699 Yampa River subwatershed 2 PP,D,MI,N,SS 2

1985–94 15

73 –106.859 Yampa River subwatershed 1 PP,D,SS 1986–88 16

73 –106.859 Yampa River subwatershed 1 PP,D,DS,MI,N,TE 2000 1

74 –106.979 Yampa River subwatershed 3 PP,D 2005 1

74 –106.980 Yampa River subwatershed 3 PP,DS,MI,N,TE,CB 2001, 2006–07 8

75 –106.993 Yampa River subwatershed 3 PP,D,DS,MI,N,TE,DOC,SS 1975–2001 243

76 –106.773 Elk River subwatershed PP,D,DS,MI,N,TE,U,DOC,SS 2

1999–2006 23

76 –106.773 Elk River subwatershed PP,D,CB,SS 1975–76 4

77 –106.753 Elk River subwatershed PP,D,DS,MI,N,TE,SS 1999–2000 11

78 –106.775 Elk River subwatershed PP,D,DS,MI,N,TE,SS 1999–2000 11

79 –107.287 Elkhead Creek subwatershed PP,D,CB,SS 1975–76 4

80 –107.085 Yampa River subwatershed 3 PP,D,DS,MI,N 1983 2

81 –106.650 Yampa River subwatershed 2 PP,D,DS,MI,N,TE,DOC 2

1975–87 10

82 –107.067 Yampa River subwatershed 1 PP,DS,TE 1979 1
104 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Appendix 3. Description of selected stream sampling sites in the Upper Yampa River watershed, Colorado, with type of water-quality 

data collected, period of water-quality record, and number of samples collected, 1975 through 2009.—Continued

[No., number; USFS, U.S. Department of the Agriculture Forest Service; PP, physical properties; D, discharge; CB, coliform bacteria; SS, suspended sediment; 

CDPHE, Colorado Department of Public Health and Environment; DS, dissolved solids; MI, major ions; N, nutrients, TE, trace elements; CODOW, Colorado 

Division of Wildlife Riverwatch Program; USGS, U.S. Geological Survey; DOC, dissolved organic carbon; CSS, City of Steamboat Springs; U, uranium; USEPA, 

U.S. Environmental Protection Agency. Subwatershed definitions: Yampa River subwatershed 1, Yampa River and tributaries upstream from Chuck Lewis State 

Wildlife Area; Yampa River subwatershed 2, Yampa River and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence; Elk River subwatershed, 

Elk River and tributaries; Yampa River subwatershed 3, Yampa River and tributaries from Elk River confluence to Town of Hayden; Yampa River subwatershed 4, 

Yampa River and tributaries from Town of Hayden to Elkhead Creek confluence; Elkhead Creek subwatershed, Elkhead Creek and tributaries. Sites with the same 

site number are considered to be at the same location. Sites with name in bold are streamgage stations; see table 1 for additional information on these sites. The 

Upper Yampa River water-quality database is available at http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml]

Site no.

(see figure 3) Site name in Upper Yampa River watershed water-quality database Sourceof data

Site

identifier Latitude

83 OAK CK D/S TOWN OF OAK CREEK @ CR 27 CDPHE 12892 40.276

84 OAK CK NEAR MOUTH @ CR 14 @ SYDNEY PEAK HORSE RANCH CDPHE 12891A 40.390

85 OAK CREEK AB OAK CREEK DRAIN NEAR OAK CREEK, CO. USGS 401725106575600 40.290

86 OAK CREEK ABOVE ROUTT, CO. USGS 401741106574600 40.295

87 OAK CREEK AT CR 35 BELOW HAYBRO, CO USGS 402121106543201 40.356

88 OAK CREEK AT P AND M COAL MINE OAK CREEK COLO CDPHE OAK02 40.3

89 OAK CREEK AT WHITECOTTON RD CDPHE OAK03 40.333

90 OAK CREEK BELOW TOWN OF OAK CREEK CDPHE 000153 40.332

91 Oak Creek Decker Pk CODOW CDOWRW-80 40.27

92 Oak Creek Habro Br CODOW CDOWRW-9 40.31

93 OAK CREEK NEAR OAK CREEK, CO. USGS 09238000 40.244

94 OAK CREEK NEAR STEAMBOAT SPRINGS, CO. USGS 402356106503000 40.399

94 OAK CK @ 22 RD ABV YAMPA R CDPHE 12891 40.399

95 PHILLIPS CREEK NEAR YAMPA, CO. USGS 400759106532500 40.133

96 PRIEST C BL SKI AREA NR STEAMBOAT SPRINGS, CO. USGS 402600106473600 40.433

97 S. FORK ELK R. @ TRAIL 1169 NR FR 443 CDPHE 12869 40.751

98 SAGE CK @ RD. 27 CDPHE 12851 40.484

99 SAGE CR AB HADEN STATION USGS 402855107101501 40.482

100 SAGE CREEK ABOVE SAGE CREEK RES, NR HAYDEN, CO. USGS 09244415 40.384

101 SAGE CREEK NEAR HAYDEN, CO. USGS 402918107094400 40.488

101 SAGE CR @ HWY 40 USGS 402917107094501 40.488

102 SAGE CREEK NEAR MOUNT HARRIS, CO. USGS 402522107134100 40.423

103 SCC87-CREEK USGS 402358107054601 40.399

104 SENECA NORTH USGS 402940107074200 40.494

105 SENECA NORTHEAST USGS 402915107074500 40.487

106 SMUIN GULCH NEAR HAYDEN, CO USGS 402829107193700 40.475

107 SMUIN TRIB. CREEK NEAR HAYDEN, CO USGS 402845107185100 40.479

108 SODA CREEK NR MOUTH AT STEAMBOAT SPRINGS,CO. USGS 402920106501900 40.489

108 SODA [Soda Creek abv second pedestrian bridge from confl with Yampa R 

in Little Toots Park

CSS SODA 40.488

109 SOUTH FORK OF FOIDEL CREEK ABOVE MINE, CO USGS 401847107063400 40.313

110 SOUTH FORK OF FOIDEL CREEK AT MOUTH, CO USGS 402008107050200 40.336

111 SPRING CREEK NR MOUTH AT STEAMBOAT SPRINGS, CO. USGS 402857106494000 40.482

112 STOKES GULCH NEAR HAYDEN, CO. USGS 09244470 40.468

113 TOW CREEK NEAR MOUTH AT US 40 BRIDGE, CO. USGS 402908107025100 40.486

114 TROUT CK @ RD. 27 CDPHE 12876H 40.312

115 TROUT CK NR. MOUTH CDPHE 12876 40.460

116 TROUT CREEK ABOVE FOIDEL CREEK NEAR MILNER, CO. USGS 402416106580800 40.404

117 TROUT CREEK ABOVE MILNER, CO. USGS 402720106591200 40.456

118 TROUT CREEK BELOW FOIDEL CREEK NEAR MILNER, CO. USGS 402536106582700 40.427

119 TROUT CREEK NEAR MILNER, CO. USGS 402816107003800 40.471

120 TROUT CREEK NEAR OAK CREEK, CO USGS 401816107011000 40.304

121 TROUT CREEK NEAR PHIPPSBURG, CO. USGS 09243000 40.151

122 WALTON CR. NEAR MOUTH @ HWY 40 CDPHE 12894 40.270

123 WALTON CREEK NEAR STEAMBOAT SPRINGS, CO.6 USGS 09238500 40.408

124 WALTON CREEK NR MOUTH AT US 40 BRIDGE, CO. USGS 402700106485400 40.450

124 WALTON CREEK @ HWY 40 CDPHE 12894A 40.450

124 WALT [Walton Creek 10m above Hwy 40 bridge] CSS WALT 40.45
Appendix 3 105

Appendix 3. Description of selected stream sampling sites in the Upper Yampa River watershed, Colorado, with type of water-quality 

data collected, period of water-quality record, and number of samples collected, 1975 through 2009.—Continued

[No., number; USFS, U.S. Department of the Agriculture Forest Service; PP, physical properties; D, discharge; CB, coliform bacteria; SS, suspended sediment; 

CDPHE, Colorado Department of Public Health and Environment; DS, dissolved solids; MI, major ions; N, nutrients, TE, trace elements; CODOW, Colorado 

Division of Wildlife Riverwatch Program; USGS, U.S. Geological Survey; DOC, dissolved organic carbon; CSS, City of Steamboat Springs; U, uranium; USEPA, 

U.S. Environmental Protection Agency. Subwatershed definitions: Yampa River subwatershed 1, Yampa River and tributaries upstream from Chuck Lewis State 

Wildlife Area; Yampa River subwatershed 2, Yampa River and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence; Elk River subwatershed, 

Elk River and tributaries; Yampa River subwatershed 3, Yampa River and tributaries from Elk River confluence to Town of Hayden; Yampa River subwatershed 4, 

Yampa River and tributaries from Town of Hayden to Elkhead Creek confluence; Elkhead Creek subwatershed, Elkhead Creek and tributaries. Sites with the same 

site number are considered to be at the same location. Sites with name in bold are streamgage stations; see table 1 for additional information on these sites. The 

Upper Yampa River water-quality database is available at http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml]

Site no.

(see figure 3) Longitude Subwatershed Type of water-quality data collected1

Period of waterquality record

(calendar year)

No. of

samples

83 –106.964 Yampa River subwatershed 1 PP,D,DS,MI,N,TE,CB 2

1999–2007 14

84 –106.843 Yampa River subwatershed 1 PP,MI,N,TE 2006–07 4

85 –106.966 Yampa River subwatershed 1 PP,D,N,TE,DOC,CB,SS 1975–76, 2005 7

86 –106.963 Yampa River subwatershed 1 PP,D,DS,MI,N,TE,DOC,SS 1975–76 5

87 –106.909 Yampa River subwatershed 1 PP,D 2005 2

88 –107.033 Yampa River subwatershed 1 PP,DS,TE 1979 1

89 –106.967 Yampa River subwatershed 1 PP,DS,TE 1979 1

90 –106.96 Yampa River subwatershed 1 PP,DS,MI,N,TE,U 1979–92 74

91 –106.95 Yampa River subwatershed 1 PP,TE 5

1991–2000 92

92 –106.95 Yampa River subwatershed 1 PP,TE 5

1991–99 110

93 –107.015 Yampa River subwatershed 1 PP,D,DS,MI,N,TE,DOC,SS 2

1975–81, 2005 13

94 –106.842 Yampa River subwatershed 1 PP,D,N,TE,DOC 1975, 2005 2

94 –106.842 Yampa River subwatershed 1 PP,D,DS,N,TE,U,CB 2

1996–2004 25

95 –106.891 Yampa River subwatershed 1 PP,D,TE 1975, 2005 2

96 –106.794 Yampa River subwatershed 2 PP,D,N 1976 3

97 –106.731 Elk River subwatershed PP,DS,MI,N,TE,CB 2001 6

98 –107.170 Yampa River subwatershed 3 PP,DS,MI,N,TE,U,CB 2001, 2004–07 7

99 –107.171 Yampa River subwatershed 3 PP,D,DS,MI,N,TE 1979 2

100 –107.193 Yampa River subwatershed 3 PP,D,DS,MI,N,TE,DOC,SS 1981–83 28

101 –107.163 Yampa River subwatershed 3 PP,D,MI,N,TE,DOC,CB,SS 1975–76, 2005 20

101 –107.163 Yampa River subwatershed 3 PP,D,DS,MI,N,TE 1979 3

102 –107.229 Yampa River subwatershed 3 PP,D,MI,N,TE,DOC 1975–76 5

103 –107.097 Yampa River subwatershed 3 PP,DS,MI,N,TE 1988 3

104 –107.129 Yampa River subwatershed 3 PP,DS,MI,N,TE 1986 1

105 –107.130 Yampa River subwatershed 3 PP,DS,MI,N,TE 1986 1

106 –107.328 Yampa River subwatershed 4 PP,D,DS,MI,N,TE,SS 1981–82 6

107 –107.315 Yampa River subwatershed 4 PP,D,DS,MI,N 1981 6

108 –106.839 Yampa River subwatershed 2 PP,D,N,CB 1975–76, 2005 6

108 –106.84 Yampa River subwatershed 2 PP,MI,N,TE,CB 2007–08 4

109 –107.110 Yampa River subwatershed 3 PP,D,DS,MI,N 1983 2

110 –107.084 Yampa River subwatershed 3 PP,D,DS,MI,N 1983 1

111 –106.828 Yampa River subwatershed 2 PP,D,N,CB 1975–76, 2005 6

112 –107.247 Yampa River subwatershed 4 PP,D,DS,MI,N,TE,DOC,SS 1978–82 39

113 –107.048 Yampa River subwatershed 3 D,CB 1975 1

114 –107.009 Yampa River subwatershed 3 PP,DS,MI,N,TE 2001 4

115 –106.989 Yampa River subwatershed 3 PP,DS,MI,N,TE,U 2

1996–2007 22

116 –106.969 Yampa River subwatershed 3 PP,D,N,TE,DOC 1975, 2005 2

117 –106.987 Yampa River subwatershed 3 PP,D,DS,MI,N,TE,SS 1981–82 11

118 –106.975 Yampa River subwatershed 3 PP,D,DS,MI,N,TE,DOC,SS 1975, 2005 2

119 –107.011 Yampa River subwatershed 3 PP,D,DS,MI,N,DOC,CB 1975, 1979, 2005 6

120 –107.020 Yampa River subwatershed 3 PP,D,DS,MI,N 1981 7

121 –107.132 Yampa River subwatershed 3 PP,D,DS,MI,N,TE,DOC 1975 1

122 –106.816 Yampa River subwatershed 2 PP,D,DS,MI,N,TE,CB 1999, 2006–07 5

123 –106.787 Yampa River subwatershed 2 PP,D,DS,MI,N,TE,SS 1982–87 45

124 –106.816 Yampa River subwatershed 2 PP,D,N,CB 1975, 2005 4

124 –106.816 Yampa River subwatershed 2 PP,DS,MI,N,TE,CB 2001–02 3

124 –106.815 Yampa River subwatershed 2 PP,MI,N,TE,CB 2007–08 4
106 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Appendix 3. Description of selected stream sampling sites in the Upper Yampa River watershed, Colorado, with type of water-quality 

data collected, period of water-quality record, and number of samples collected, 1975 through 2009.—Continued

[No., number; USFS, U.S. Department of the Agriculture Forest Service; PP, physical properties; D, discharge; CB, coliform bacteria; SS, suspended sediment; 

CDPHE, Colorado Department of Public Health and Environment; DS, dissolved solids; MI, major ions; N, nutrients, TE, trace elements; CODOW, Colorado 

Division of Wildlife Riverwatch Program; USGS, U.S. Geological Survey; DOC, dissolved organic carbon; CSS, City of Steamboat Springs; U, uranium; USEPA, 

U.S. Environmental Protection Agency. Subwatershed definitions: Yampa River subwatershed 1, Yampa River and tributaries upstream from Chuck Lewis State 

Wildlife Area; Yampa River subwatershed 2, Yampa River and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence; Elk River subwatershed, 

Elk River and tributaries; Yampa River subwatershed 3, Yampa River and tributaries from Elk River confluence to Town of Hayden; Yampa River subwatershed 4, 

Yampa River and tributaries from Town of Hayden to Elkhead Creek confluence; Elkhead Creek subwatershed, Elkhead Creek and tributaries. Sites with the same 

site number are considered to be at the same location. Sites with name in bold are streamgage stations; see table 1 for additional information on these sites. The 

Upper Yampa River water-quality database is available at http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml]

Site no.

(see figure 3) Site name in Upper Yampa River watershed water-quality database Sourceof data

Site

identifier Latitude

125 WATERING TROUGH GULCH NEAR HAYDEN, CO. USGS 09244460 40.382

126 WAYS GULCH AT HAHNS PEAK, CO SITE 1A USGS 404756106555100 40.799

127 WEST FORK ELK RIVER NR MOUTH AT US 40 BRIDGE,CO. USGS 402903106584100 40.484

128 WOLF CREEK NEAR HAYDEN, CO. USGS 402832107080200 40.476

128 WOLF CREEK AT HWY 40 CDPHE 12802C 40.476

129 YAMPA ABOVE OAK CREEK CONFLUENCE CDPHE 000088 40.383

130 YAMPA R 0.5 MI DSTRM STP BELOW STMBT SPRGS. USGS 403015106523000 40.504

131 YAMPA R AB DAM SITE NR OAK CREEK, CO USGS 401609106525201 40.269

132 YAMPA R AT 13TH ST BRIDGE AT STEAMBOAT SPRINGS, CO USGS 402922106502701 40.489

133 YAMPA R AT JAMES BRN BR BLW STEAMBOAT SPRINGS, CO USGS 402946106512601 40.496

133 YMP-7 [Yampa River 100m above James Brown Bridge] CSS YMP-7 40.496

134 YAMPA R AT US HWY 40 CDPHE 12802B 40.495

135 YAMPA R BL KOA CAMPGROUNDS NR STEAMBOAT SPG, CO. USGS 403017106525800 40.505

136 YAMPA R. @ CR 14 FISHING ACCESS CDPHE 12806D 40.475

137 YAMPA R. ABV. PHIPPSBURG CDPHE 12814 40.227

138 YAMPA R. BLW STAGECOACH RES. CDPHE 12808 40.287

139 YAMPA R. D/S STAGECOACH RES. DAM CDPHE 12808P 40.288

140 YAMPA R. N. OF HAYDEN @ CALIFORNIA PARK RD CDPHE 12802 40.502

141 YAMPA R. NR MOUNT HARRIS BLW HWY 40 BRIDGE CDPHE 12805 40.488

142 YAMPA R. U/S LAKE CATAMOUNT @ CR187 CDPHE 12807 40.341

143 YAMPA RIVER AB OAK CREEK NR STEAMBOAT SPGS, CO. USGS 402356106500000 40.399

143 YAMPA R. ABV OAK CREEK CDPHE 12811 40.399

144 YAMPA RIVER AB SEWAGE PLANT BL STEAMBOAT SPG,CO. USGS 402934106505400 40.493

145 YAMPA RIVER ABOVE ELK RIVER NEAR MILNER, CO. USGS 402932106564900 40.492

145 YAMPA RIVER ABV ELK RIVER USGS 402936106565000 40.493

146 YAMPA RIVER ABOVE ELKHEAD CREEK NEAR HAYDEN, CO USGS 09244490 40.518

147 YAMPA RIVER ABOVE STAGECOACH RESERVOIR, CO USGS 09237450 40.269

147 YAMPA R. U/S STAGECOACH RES @ CR16 CDPHE 12809 40.269

148 YAMPA RIVER ABOVE TOW CREEK OIL FIELD, CO. USGS 402902107043600 40.484

149 YAMPA RIVER AT ELK RIVER JUNCTION NR MILNER, CO. USGS 402902106580000 40.484

150 YAMPA RIVER AT HAYDEN USGS 403007107155001 40.502

150 YAMPA RIVER AT HAYDEN, CO. USGS 403006107154800 40.502

151 YAMPA RIVER AT MILNER, CO. USGS 402840107004200 40.478

151 YAMPA RIVER AT MILNER CDPHE 000038 40.479

152 YAMPA RIVER AT PHIPPSBURG, CO. USGS 401418106562200 40.238

153 YAMPA RIVER AT STEAMBOAT SPRINGS, CO USGS 09239500 40.483

153 YAMPA R. @ 5TH ST. BRIDGE IN STEAMBOAT CDPHE 12806 40.483

153 Yampa River 5th St Br CODOW CDOWRW-607 40.48

154 YAMPA RIVER BELOW DIVERSION, NEAR HAYDEN, CO. USGS 09244410 40.488

155 YAMPA RIVER BELOW HAYDEN, CO. USGS 402930107174200 40.492

155 YAMPA R. WEST OF HAYDEN @ HWY 40 CDPHE 12802A 40.492

156 YAMPA RIVER BELOW MORGAN CREEK NEAR HAYDEN, CO. USGS 403051107124500 40.514

157 YAMPA RIVER BELOW OAK CREEK NR STEAMBOAT SPG,CO. USGS 402544106493600 40.429

158 Yampa River Below Stagecoach CODOW CDOWRW-81 40.28

158 YAMPA RIVER BELOW STAGECOACH RESERVOIR, CO USGS 09237500 40.285

159 YAMPA RIVER BELOW STEAMBOAT II SEWAGE PLANT, CO. USGS 403002106545500 40.501

160 YAMPA RIVER BELOW TROUT CREEK AT MILNER, CO. USGS 402854107020500 40.482

161 YAMPA RIVER BELOW WALTON CREEK, CO. USGS 402737106493700 40.460
Appendix 3 107

Appendix 3. Description of selected stream sampling sites in the Upper Yampa River watershed, Colorado, with type of water-quality 

data collected, period of water-quality record, and number of samples collected, 1975 through 2009.—Continued

[No., number; USFS, U.S. Department of the Agriculture Forest Service; PP, physical properties; D, discharge; CB, coliform bacteria; SS, suspended sediment; 

CDPHE, Colorado Department of Public Health and Environment; DS, dissolved solids; MI, major ions; N, nutrients, TE, trace elements; CODOW, Colorado 

Division of Wildlife Riverwatch Program; USGS, U.S. Geological Survey; DOC, dissolved organic carbon; CSS, City of Steamboat Springs; U, uranium; USEPA, 

U.S. Environmental Protection Agency. Subwatershed definitions: Yampa River subwatershed 1, Yampa River and tributaries upstream from Chuck Lewis State 

Wildlife Area; Yampa River subwatershed 2, Yampa River and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence; Elk River subwatershed, 

Elk River and tributaries; Yampa River subwatershed 3, Yampa River and tributaries from Elk River confluence to Town of Hayden; Yampa River subwatershed 4, 

Yampa River and tributaries from Town of Hayden to Elkhead Creek confluence; Elkhead Creek subwatershed, Elkhead Creek and tributaries. Sites with the same 

site number are considered to be at the same location. Sites with name in bold are streamgage stations; see table 1 for additional information on these sites. The 

Upper Yampa River water-quality database is available at http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml]

Site no.

(see figure 3) Longitude Subwatershed Type of water-quality data collected1

Period of waterquality record

(calendar year)

No. of

samples

125 –107.281 Yampa River subwatershed 4 PP,D,DS,MI,N,TE,DOC,SS 1978–81 27

126 –106.931 Elk River subwatershed PP,D,MI,N,TE,DOC 1975 1

127 –106.979 Yampa River subwatershed 3 PP,D,N,CB 1975, 2005 5

128 –107.134 Yampa River subwatershed 3 PP,D,N,TE,DOC 1975 3

128 –107.134 Yampa River subwatershed 3 PP,MI,N,TE 2006–07 4

129 –106.817 Yampa River subwatershed 1 PP,DS,MI,N,TE,U 1975-93 101

130 –106.876 Yampa River subwatershed 2 PP,N,CB 1976 2

131 –106.882 Yampa River subwatershed 1 PP,D,SS 1986–88 17

132 –106.841 Yampa River subwatershed 2 PP 2005 1

133 –106.857 Yampa River subwatershed 2 PP 2005 1

133 –106.857 Yampa River subwatershed 2 PP,MI,N,TE,CB 2007–08 4

134 –107.158 Yampa River subwatershed 3 PP,MI,N,TE 2006–07 4

135 –106.883 Yampa River subwatershed 2 PP,D,N,CB 1975–76 5

136 –106.824 Yampa River subwatershed 1 PP,DS,MI,N,TE 1999 1

137 –106.941 Yampa River subwatershed 1 PP,D,DS,MI,N,TE,U,CB 1996–2004 34

138 –106.829 Yampa River subwatershed 1 PP,D,DS,MI,N,TE 1996–99 14

139 –106.827 Yampa River subwatershed 1 PP,DS,MI,N,TE,CB 2

2000–07 21

140 –107.264 Yampa River subwatershed 3 PP,DS,MI,N,TE,CB 2

1996–99 13

141 –107.158 Yampa River subwatershed 3 PP,DS,MI,N,TE 1999 1

142 –106.808 Yampa River subwatershed 1 PP,DS,MI,N,TE,CB 1999 1

143 –106.834 Yampa River subwatershed 1 PP,D,DS,MI,N,TE,DOC,CB,SS 1975–76, 2005 6

143 –106.834 Yampa River subwatershed 1 PP,D,DS,MI,N,TE,CB 1996–2002 30

144 –106.849 Yampa River subwatershed 2 PP,D,N,CB,SS 1975–76, 2005 11

145 –106.948 Yampa River subwatershed 2 PP,D,N,TE,CB,DOC 1975–76 10

145 –106.948 Yampa River subwatershed 2 PP,D,DS,MI,N,DOC 2

1999–2005 5

146 –107.400 Yampa River subwatershed 4 PP,D 2004–05 13

147 –106.881 Yampa River subwatershed 1 PP,D,DS,MI,N,TE,CB,SS 1988–2005 202

147 –106.881 Yampa River subwatershed 1 PP,DS,MI,N,TE,CB 2

1999–2007 22

148 –107.077 Yampa River subwatershed 3 PP,D,N,CB 1975 3

149 –106.967 Yampa River subwatershed 2 PP,D,N,CB 1975–76 5

150 –107.265 Yampa River subwatershed 3 PP,D,TE 1979 1

150 –107.264 Yampa River subwatershed 3 PP,D,MI,N,TE,DOC,CB 1975–76, 2005 10

151 –107.012 Yampa River subwatershed 3 PP,D,N,CB 1975, 2005 5

151 –107.013 Yampa River subwatershed 3 PP,DS,MI,N,TE,U,CB 8

1975–2007 179

152 –106.940 Yampa River subwatershed 1 PP,D,N,TE,DOC,CB,SS 1975–76, 2005 7

153 –106.832 Yampa River subwatershed 2 PP,D,DS,MI,N,TE,DOC,CB,SS 1975–2009 358

153 –106.832 Yampa River subwatershed 2 PP,DS,MI,N,TE,U,CB 8

1996–2007 38

153 –106.83 Yampa River subwatershed 2 PP,D,TE 1998–2000 17

154 –107.160 Yampa River subwatershed 3 PP,D,DS,MI,N,TE,DOC,CB,SS 2

1975–2005 158

155 –107.296 Yampa River subwatershed 4 PP,D,DS,MI,N,TE,DOC,CB 1975–76, 2005 8

155 –107.296 Yampa River subwatershed 4 PP,DS,MI,N,TE,CB 2000–02 18

156 –107.213 Yampa River subwatershed 3 PP,D,N,CB 1975 3

157 –106.827 Yampa River subwatershed 2 PP,D,N,TE,DOC,CB,SS 1975–76, 2005 10

158 –106.82 Yampa River subwatershed 1 PP,D,MI,N,TE 9

1991–2004 134

158 –106.831 Yampa River subwatershed 1 PP,D,DS,MI,N,TE,DOC,CB,SS 1984–2005 263

159 –106.916 Yampa River subwatershed 2 PP,D,N,CB 1975–76 5

160 –107.035 Yampa River subwatershed 3 PP,D,N,TE,DOC,CB 1975–76, 2005 9

161 –106.828 Yampa River subwatershed 2 PP,N,CB 1975–76 6
108 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Appendix 3. Description of selected stream sampling sites in the Upper Yampa River watershed, Colorado, with type of water-quality 

data collected, period of water-quality record, and number of samples collected, 1975 through 2009.—Continued

[No., number; USFS, U.S. Department of the Agriculture Forest Service; PP, physical properties; D, discharge; CB, coliform bacteria; SS, suspended sediment; 

CDPHE, Colorado Department of Public Health and Environment; DS, dissolved solids; MI, major ions; N, nutrients, TE, trace elements; CODOW, Colorado 

Division of Wildlife Riverwatch Program; USGS, U.S. Geological Survey; DOC, dissolved organic carbon; CSS, City of Steamboat Springs; U, uranium; USEPA, 

U.S. Environmental Protection Agency. Subwatershed definitions: Yampa River subwatershed 1, Yampa River and tributaries upstream from Chuck Lewis State 

Wildlife Area; Yampa River subwatershed 2, Yampa River and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence; Elk River subwatershed, 

Elk River and tributaries; Yampa River subwatershed 3, Yampa River and tributaries from Elk River confluence to Town of Hayden; Yampa River subwatershed 4, 

Yampa River and tributaries from Town of Hayden to Elkhead Creek confluence; Elkhead Creek subwatershed, Elkhead Creek and tributaries. Sites with the same 

site number are considered to be at the same location. Sites with name in bold are streamgage stations; see table 1 for additional information on these sites. The 

Upper Yampa River water-quality database is available at http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml]

Site no.

(see figure 3) Site name in Upper Yampa River watershed water-quality database Sourceof data

Site

identifier Latitude

162 YAMPA RIVER BELOW YAMPA, CO. USGS 401048106544800 40.180

162 Yampa River Willow Cabin Br CODOW CDOWRW-7 40.18

162 YAMPA R. BLW YAMPA @ CR21 CDPHE 12815 40.183

163 YAMPA RIVER BL SEWAGE PLANT BL STEAMBOAT SPG,CO. USGS 402958106515200 40.499

163 YAMPA R 0.2 MI BL STP BL STEAMBOAT SPRINGS, CO. USGS 402958106515201 40.499

164 Yampa River East Br CODOW CDOWRW-13 40.48

165 Yampa River Hunt Creek CODOW CDOWRW-3260 40.22

166 Yampa River Library CODOW CDOWRW-12 40.48

167 Yampa River N of Stagecoach CODOW CDOWRW-3476 40.29

168 YAMPA RIVER NEAR HAYDEN, CO. USGS 09244400 40.489

169 YAMPA RIVER NR SIDNEY, COLO. USGS 402230106493000 40.375

169 YAMPA R. D/S LAKE CATAMOUNT @ HWY 131 CDPHE 12806F 40.375

170 Yampa River Stagecoach Res CODOW CDOWRW-8 40.26

171 Yampa River SWA Br CODOW CDOWRW-10 40.39

172 Yampa River Treehouse CODOW CDOWRW-11 40.48

173 Yampa River West Br CODOW CDOWRW-14 40.49

174 YMP-1 [Yampa River 200m above confl Walton Creek] CSS YMP-1 40.449

175 YMP-2 [Yampa River 35m above confl Fish Creek] CSS YMP-2 40.466

176 YMP-3A [Yampa River 70m above pedestrian bridge and hot spring 

outflow in Weiss Park]

CSS YMP-3A 40.481
Appendix 3 109

Appendix 3. Description of selected stream sampling sites in the Upper Yampa River watershed, Colorado, with type of water-quality 

data collected, period of water-quality record, and number of samples collected, 1975 through 2009.—Continued

[No., number; USFS, U.S. Department of the Agriculture Forest Service; PP, physical properties; D, discharge; CB, coliform bacteria; SS, suspended sediment; 

CDPHE, Colorado Department of Public Health and Environment; DS, dissolved solids; MI, major ions; N, nutrients, TE, trace elements; CODOW, Colorado 

Division of Wildlife Riverwatch Program; USGS, U.S. Geological Survey; DOC, dissolved organic carbon; CSS, City of Steamboat Springs; U, uranium; USEPA, 

U.S. Environmental Protection Agency. Subwatershed definitions: Yampa River subwatershed 1, Yampa River and tributaries upstream from Chuck Lewis State 

Wildlife Area; Yampa River subwatershed 2, Yampa River and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence; Elk River subwatershed, 

Elk River and tributaries; Yampa River subwatershed 3, Yampa River and tributaries from Elk River confluence to Town of Hayden; Yampa River subwatershed 4, 

Yampa River and tributaries from Town of Hayden to Elkhead Creek confluence; Elkhead Creek subwatershed, Elkhead Creek and tributaries. Sites with the same 

site number are considered to be at the same location. Sites with name in bold are streamgage stations; see table 1 for additional information on these sites. The 

Upper Yampa River water-quality database is available at http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml]

Site no.

(see figure 3) Longitude Subwatershed Type of water-quality data collected1

Period of waterquality record

(calendar year)

No. of

samples

162 –106.914 Yampa River subwatershed 1 PP,D,TE 1975, 2005 3

162 –106.91 Yampa River subwatershed 1 PP,D 1990–99 131

162 –106.915 Yampa River subwatershed 1 PP,D,DS,MI,N,TE,CB 1999–2002 14

163 –106.865 Yampa River subwatershed 2 PP,D,N,CB 1975 3

163 –106.865 Yampa River subwatershed 2 PP,D,N,CB 1976 2

164 –107.15 Yampa River subwatershed 3 PP,D,TE 1990–96, 1998 49

165 –106.94 Yampa River subwatershed 1 PP,TE 1993 1

166 –106.84 Yampa River subwatershed 2 PP,TE 1991–92, 1996 23

167 –106.8 Yampa River subwatershed 1 PP 1993 1

168 –107.160 Yampa River subwatershed 3 PP,D,DS,MI,N,TE 1975, 1979, 2005 6

169 –106.826 Yampa River subwatershed 1 PP 2005 1

169 –106.825 Yampa River subwatershed 1 PP,DS,MI,N,TE,CB 1999 1

170 –106.88 Yampa River subwatershed 1 PP,D,MI,N,TE 9

1990–2004 150

171 –106.83 Yampa River subwatershed 1 PP,D,TE 1991–98 147

172 –106.83 Yampa River subwatershed 2 PP,D,TE 1991, 1996 15

173 –107.29 Yampa River subwatershed 4 PP,TE 2

1990–2001 45

174 –106.820 Yampa River subwatershed 2 PP,MI,N,TE,CB 2007–08 4

175 –106.830 Yampa River subwatershed 2 PP,MI,N,TE,CB 2007–08 4

176 –106.828 Yampa River subwatershed 2 PP,MI,N,TE,CB 2007–08 4

1

When multiple sample were collected at a site, all types of water-quality data listed may not be available for each sample.

2

Samples were not collected every year in the period of record.

3

Samples were not collected in 1978.

4

Samples were not collected in 1984.

5

Samples were not collected in 1997.

6

Site also is Colorado Division of Water Resources streamflow gage WLTNCKCO. See table 1 for additional information.

7

Site also is Colorado Division of Water Resources streamflow gage YAMABVCO. See table 1 for additional information.

8

Samples were not collected in 2005.

9

Samples were not collected in 2001.
110 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Appendix 4. Description of selected lake and reservoir samlping sites in the Upper Yampa River watershed, Colorado, with type of 

water-quality data collected, period of water-quality record, and number of sample days, 1985 through 2009.

[No., number; USGS, U.S. Geological Survey; PP, physical properties; N, nutrients; CHL, chlorophyll; MI, major ions; TE, trace elements; OC, organic carbon; 

SI, stable isotopes; CDPHE, Colorado Department of Public Health and Environment; CB, coliform bacteria. Subwatershed definitions: Yampa River subwatershed 1, Yampa River and tributaries upstream from Chuck Lewis State Wildlife Area; Yampa River subwatershed 2, Yampa River and tributaries from Chuck 

Lewis State Wildlife Area to Elk River confluence; Elk River subwatershed, Elk River and tributaries; Elkhead Creek subwatershed, Elkhead Creek and tributaries. The Upper Yampa River water-quality database is available at http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml]

Site name in Upper Yampa River 

watershed water-quality database

Source

of data Site identifier Latitude Longitude Subwatershed

ELKHEAD RESERVOIR SITE 1A USGS 403507107214900 40.585 –107.364 Elkhead Creek subwatershed

ELKHEAD RESERVOIR SITE 1B USGS 403506107214500 40.585 –107.363 Elkhead Creek subwatershed

ELKHEAD RESERVOIR SITE 2A USGS 403439107223800 40.577 –107.378 Elkhead Creek subwatershed

ELKHEAD RESERVOIR SITE 2B USGS 403437107223300 40.577 –107.376 Elkhead Creek subwatershed

ELKHEAD RESERVOIR SITE 2C USGS 403435107222900 40.576 –107.375 Elkhead Creek subwatershed

ELKHEAD RESERVOIR SITE 3A USGS 403336107230700 40.560 –107.386 Elkhead Creek subwatershed

ELKHEAD RESERVOIR SITE 3B USGS 403333107230100 40.559 –107.384 Elkhead Creek subwatershed

ELKHEAD RESERVOIR SITE 3C USGS 403331107225500 40.559 –107.383 Elkhead Creek subwatershed

LAKE ELBERT USGS 403803106422500 40.634 –106.708 Yampa River subwatershed 2

LONG LAKE RESERVOIR USGS 402833106412400 40.476 –106.691 Yampa River subwatershed 2

STAGECOACH RES, NR PHIPPSBURGH, 

250M W OF DAM

CDPHE STAGE01 40.285 –106.835 Yampa River subwatershed 1

STAGECOACH RESERVOIR,

NR PHIPPSBURGH,INLET SIDE

CDPHE STAGE02 40.276 –106.860 Yampa River subwatershed 1

STAGECOACH RESERVOIR AT DAM, 

COLORADO

USGS 401707106495800 40.285 –106.833 Yampa River subwatershed 1

STAGECOACH RESERVOIR NEAR 

INLET, NR OAK CREEK, CO.

USGS 401628106515500 40.274 –106.866 Yampa River subwatershed 1

STAGECOACH RESERVOIR NR DAM 

[UPPER and LOWER]

CDPHE 12812A, 12812B 40.285 –106.835 Yampa River subwatershed 1

STEAMBOAT LAKE NR DAM [UPPER 

and LOWER]

CDPHE 12866A, 12866B 40.793 –106.949 Elk River subwatershed
Appendix 4 111

Appendix 4. Description of selected lake and reservoir samlping sites in the Upper Yampa River watershed, Colorado, with type of 

water-quality data collected, period of water-quality record, and number of sample days, 1985 through 2009.—Continued

[No., number; USGS, U.S. Geological Survey; PP, physical properties; N, nutrients; CHL, chlorophyll; MI, major ions; TE, trace elements; OC, organic 

carbon; SI, stable isotopes; CDPHE, Colorado Department of Public Health and Environment; CB, coliform bacteria. Subwatershed definitions: Yampa River 

subwatershed 1, Yampa River and tributaries upstream from Chuck Lewis State Wildlife Area; Yampa River subwatershed 2, Yampa River and tributaries from 

Chuck Lewis State Wildlife Area to Elk River confluence; Elk River subwatershed, Elk River and tributaries; Elkhead Creek subwatershed, Elkhead Creek and 

tributaries. The Upper Yampa River water-quality database is available at http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml]

Site name in Upper Yampa River 

watershed water-quality database

Type of water-quality 

data collected

Period of waterquality recordNo. of 

sample days1

ELKHEAD RESERVOIR SITE 1A PP 7/12/1995–8/2/2001 18

ELKHEAD RESERVOIR SITE 1B PP,N,CHL 7/12/1995–8/2/2001 18

ELKHEAD RESERVOIR SITE 2A PP 7/12/1995–8/2/2001 18

ELKHEAD RESERVOIR SITE 2B PP,N,CHL 7/12/1995–8/2/2001 18

ELKHEAD RESERVOIR SITE 2C PP 7/12/1995–8/2/2001 18

ELKHEAD RESERVOIR SITE 3A PP 7/12/1995–8/2/2001 18

ELKHEAD RESERVOIR SITE 3B PP,N,CHL 7/12/1995–8/2/2001 18

ELKHEAD RESERVOIR SITE 3C PP 7/12/1995–8/2/2001 18

LAKE ELBERT PP,MI,N,TE,OC,CHL,SI 7/18/1985–9/9/2009 74

LONG LAKE RESERVOIR PP,MI,N,TE,OC,CHL,SI 7/16/1985–8/11/2005 64

STAGECOACH RES, NR PHIPPSBURGH,

250M W OF DAM

PP,MI,N,TE,CHL 10/10/1990 1

STAGECOACH RESERVOIR,

NR PHIPPSBURGH,INLET SIDE

PP,MI,N,TE,CHL 10/10/1990 1

STAGECOACH RESERVOIR AT DAM,

COLORADO

PP,TDS,MI,N,TE,OC,CB 4/26/1990–11/7/1992 20

STAGECOACH RESERVOIR NEAR

INLET,NR OAK CREEK, CO.

PP,TDS,MI,N,TE,OC,CB 4/26/1990–11/7/1992 20

STAGECOACH RESERVOIR NR DAM 

[UPPER and LOWER]

PP,MI,N,TE,CHL 7/25/2006 1

STEAMBOAT LAKE NR DAM [UPPER 

and LOWER]

PP,MI,N,TE,CHL 7/25/2006 1

1

Number of days in which water samples were collected at the site for a lake or reservoir. Samples collected on the same day but at different times or depths in 

the lake or reservoir are counted as one sample day.
112 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Appendix 5. Description of selected groundwater sampling sites in the Upper Yampa River watershed, Colorado, with geologic unit 

description, type of water-quality data collected, period of water-quality record, number of samples collected, and constituents with 

exceedances of Colorado Department of Public Health and Environment water-quality standards for groundwater, 1975 through 1989 

and 1998.—Continued

[No., number; CDPHE, Colorado Department of Public Health and Environment; USGS, U.S. Geological Survey; PP, physical properties; --, water-quality 

standard not exceeded; DS, dissolved solids; MI, major ions; N, nutrients; TE, trace elements; Fe, iron; Mn, manganese; NO3+NO2, nitrate plus nitrite; Zn, zinc; 

Sul, sulfate; Cd, cadmium; Ar, arsenic; R, radiochemical; Chl, chloride; Bo, boron; Pb, lead; SI, stable isotopes; OC, organic carbon; Fl, fluoride; Be, beryllium; 

Cu, copper; Se, selenium; Mo, molybdenum; CDOA, Colorado Department of Agriculture. The Upper Yampa River water-quality database is available at 

http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml]

Site no.

(see figure 15)

Site name in Upper Yampa River watershed 

water-quality database

Source 

of data Site Identifier Latitude Longitude

180 SB00208529DAD1 USGS 400637106563601 40.110 –106.944

181 SB00208521CDD1 USGS 400716106555901 40.121 –106.934

182 SB00208518DDC1 USGS 400809106574301 40.136 –106.963

183 SB00208514CCB1 USGS 400819106541001 40.139 –106.903

184 SB00208517CBA USGS 400845106572001 40.146 –106.956

185 SB00208511CAB1 USGS 400921106534601 40.156 –106.897

186 SB00208510ADC1 USGS 400930106542101 40.158 –106.906

187 SB00208306DBC1 USGS 401007106442101 40.169 –106.740

188 SB00308635CCD1 USGS 401053107005201 40.181 –107.015

189 SB00308528ACC1 USGS 401210106555401 40.203 –106.932

190 SB00308528ACC2 USGS 401210106555601 40.203 –106.933

191 SB00308516CCD1 USGS 401330106562001 40.225 –106.939

192 SB00308016CDB1 USGS 401340107030201 40.228 –107.051

193 SB00308517DBB1 USGS 401349106565501 40.230 –106.949

194 SB00308517ADC1 USGS 401352106564201 40.231 –106.944

195 SB00308517ADD2 USGS 401355106563501 40.232 –106.944

196 SB00308517ADD1 USGS 401355106563601 40.232 –106.944

197 SB00308509BDC1 USGS 401418106560301 40.238 –106.935

198 SB00308618BBA1 USGS 401425107052301 40.240 –107.090

199 SB00308503ADB1 USGS 401551106541201 40.264 –106.904

200 SB00308605ACB1 USGS 401552107035301 40.264 –107.065

201 SB00408531DDC1 USGS 401611106575001 40.270 –106.964

202 SB00408530ACD1 USGS 401729106575701 40.291 –106.966

203 SB00408729ADA1 USGS 401735107104201 40.293 –107.179

204 SB00408622CCC1 USGS 401754107020501 40.298 –107.035

205 SB00408622CDB1 USGS 401801107015101 40.300 –107.031

206 SB00408724DBD USGS 401804107062101 40.301 –107.106

207 SB00408724BCB USGS 401826107070401 40.307 –107.118

208 SB00408619BBD USGS 401837107054501 40.310 –107.096

209 SB00408620AAA1 USGS 401842107032201 40.312 –107.057

210 SB00408614DCC1 USGS 401847107003101 40.313 –107.009

211 SB00408614CDD FOIDEL MIDDLE CRK 8 USGS 401847107003301 40.313 –107.011

212 SB00408517CCB1 USGS 401857106573101 40.316 –106.959

213 SB00408713AAD US GOVT USGS 401904107060800 40.318 –107.103

214 SB00408713DAA USGS 401904107060801 40.318 –107.103

215 SB00408616CBA FOIDEL MIDDLE CRK 3 USGS 401912107031300 40.320 –107.054

216 SB00408616CBA USGS 401912107031301 40.320 –107.054

217 SB00408618BDA USGS 401922107050701 40.323 –107.086

218 SB00408416BBB1 USGS 401931106492301 40.325 –106.824

219 SB00408612CBD1 USGS 401935106595401 40.326 –106.999

220 SB00408710CCD1 USGS 401939107091201 40.327 –107.154

221 SB00408611DCC USGS 401941107002001 40.328 –107.006

222 SB00408709CBC DALE WELDON USGS 401950107103300 40.331 –107.176

223 SB00408407DBB1 USGS 401959106510101 40.333 –106.851

224 SB00408407BDB1 USGS 402007106513001 40.335 –106.859

225 SB00408610BAD USGS 402015107014501 40.337 –107.030

226 SB00408610BAD FOIDEL-MIDDLE CREEK 4 USGS 402015107015500 40.337 –107.033

227 SB00408512AAD1 USGS 402023106515201 40.340 –106.865

228 SB00508634CAB1 USGS 402041107013301 40.345 –107.026

229 SB00508433DBB1 USGS 402049106485501 40.347 –106.816
Appendix 5 113

Appendix 5. Description of selected groundwater sampling sites in the Upper Yampa River watershed, Colorado, with geologic unit 

description, type of water-quality data collected, period of water-quality record, number of samples collected, and constituents with 

exceedances of Colorado Department of Public Health and Environment water-quality standards for groundwater, 1975 through 1989 

and 1998.—Continued

[No., number; CDPHE, Colorado Department of Public Health and Environment; USGS, U.S. Geological Survey; PP, physical properties; --, water-quality 

standard not exceeded; DS, dissolved solids; MI, major ions; N, nutrients; TE, trace elements; Fe, iron; Mn, manganese; NO3+NO2, nitrate plus nitrite; Zn, zinc; 

Sul, sulfate; Cd, cadmium; Ar, arsenic; R, radiochemical; Chl, chloride; Bo, boron; Pb, lead; SI, stable isotopes; OC, organic carbon; Fl, fluoride; Be, beryllium; 

Cu, copper; Se, selenium; Mo, molybdenum; CDOA, Colorado Department of Agriculture. The Upper Yampa River water-quality database is available at 

http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml]

Site no.

(see figure 15) Geologic unit description Type of water-quality data collected1

Period of waterquality record 

(calendar year)

No. of 

sample 

days

No. of

samples2

Constituent with 

exceedance of CDPHE 

water-quality standard3

180 Alluvium, flood plain PP 1978 1 1 --

181 Mancos Shale PP, DS, MI, N, TE 1978 1 1 --

182 Curtis Formation of 

San Rafael Group

PP, DS, MI, N, TE 1978 1 1 --

183 Alluvium, flood plain PP 1978 1 1 --

184 Unknown PP, DS, MI, TE 1981 1 1 --

185 Mancos Shale PP, DS, MI, N, TE 1978 1 1 Fe, Mn

186 Alluvium, flood plain PP, DS, MI, N, TE 1978 1 1 --

187 Browns Park Formation PP 1978 1 1 --

188 Mancos Shale PP, DS, MI, N, TE 1978 1 1 --

189 Browns Park Formation PP 1978 1 1 --

190 Browns Park Formation PP 1978 1 1 --

191 Browns Park Formation PP, DS, MI, N, TE 1978 1 1 --

192 Alluvium, flood plain PP, DS, MI, N, TE 1975 1 1 --

193 Browns Park Formation PP 1978 1 1 --

194 Browns Park Formation PP 1978 1 1 --

195 Browns Park Formation PP 1978 1 1 --

196 Alluvium, flood plain PP 1978 1 1 --

197 Mancos Shale PP, DS, MI, N, TE 1978 1 1 NO3

+NO2, Zn

198 Alluvium, flood plain PP 1978 1 1 pH

199 Unknown PP 1975 1 1 --

200 Alluvium, flood plain PP 1975 1 1 --

201 Unknown PP, DS, MI, N, TE 1975, 1978 2 2 --

202 Unknown PP, DS, MI, N, TE 1975 2 2 Sul, Fe, Mn

203 Unknown PP 1975 1 1 --

204 Alluvium, flood plain PP 1975 1 1 --

205 Mesaverde Group PP, DS, MI, N, TE 1978 1 1 --

206 Mesaverde Group PP, DS, MI, N, TE 1977, 1980 2 2 Sul, Mn (2)

207 Mesaverde Group PP, DS, MI, N, TE 1977, 1980 2 2 Fe, Mn

208 Mesaverde Group PP, DS, MI, N, TE 1977, 1980 3 3 Mn (2)

209 Unknown PP 1975 1 1 --

210 Mesaverde Group PP, DS, MI, N, TE 1977 1 1 Mn

211 Unknown PP, DS, MI, N, TE 1975 1 1 pH

212 Alluvium, flood plain PP 1975 1 1 --

213 Unknown PP, DS, MI, N, TE 1975–76 2 2 Sul (2), Fe (2), Mn

214 Mesaverde Group PP, DS, MI, N, TE 1977, 1980 2 2 Sul (2), Fe (2), Cd, Mn

215 Unknown PP, DS, MI, N, TE 1975 1 1 pH

216 Mesaverde Group PP, DS, MI, N, TE 1977 1 1 --

217 Mesaverde Group PP, DS, MI, N, TE 1977 1 1 pH, Fe, Mn

218 Browns Park Formation PP 1978 1 1 --

219 Mesaverde Group PP, DS, MI, N, TE 1980 1 1 pH

220 Alluvium, flood plain PP 1975 1 1 --

221 Unknown PP, DS, MI, N, TE 1980 1 1 Mn

222 Mancos Shale PP, DS, MI, N, TE 1975 1 1 Sul

223 Browns Park Formation PP, DS, MI, N, TE 1978 1 1 --

224 Browns Park Formation PP 1978 1 1 --

225 Mesaverde Group PP, DS, MI, N, TE 1977 1 1 Mn

226 Valley-fill deposits PP, DS, MI, N, TE 1975 1 1 Fe, Mn

227 Browns Park Formation PP 1978 1 1 --

228 Unknown PP, DS, MI, N, TE 1975 2 2 Mn

229 Alluvium, flood plain PP 1978 1 1 --
114 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Appendix 5. Description of selected groundwater sampling sites in the Upper Yampa River watershed, Colorado, with geologic unit 

description, type of water-quality data collected, period of water-quality record, number of samples collected, and constituents with 

exceedances of Colorado Department of Public Health and Environment water-quality standards for groundwater, 1975 through 1989 

and 1998.—Continued

[No., number; CDPHE, Colorado Department of Public Health and Environment; USGS, U.S. Geological Survey; PP, physical properties; --, water-quality 

standard not exceeded; DS, dissolved solids; MI, major ions; N, nutrients; TE, trace elements; Fe, iron; Mn, manganese; NO3+NO2, nitrate plus nitrite; Zn, zinc; 

Sul, sulfate; Cd, cadmium; Ar, arsenic; R, radiochemical; Chl, chloride; Bo, boron; Pb, lead; SI, stable isotopes; OC, organic carbon; Fl, fluoride; Be, beryllium; 

Cu, copper; Se, selenium; Mo, molybdenum; CDOA, Colorado Department of Agriculture. The Upper Yampa River water-quality database is available at 

http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml]

Site no.

(see figure 15)

Site name in Upper Yampa River watershed 

water-quality database

Source 

of data Site Identifier Latitude Longitude

230 SB00508433DBB GLEN BARBER USGS 402050106475500 40.347 –106.799

231 SB00508636BDD1 USGS 402056106590901 40.349 –106.986

232 SB00508622DCC1 USGS 402106107011801 USGS 402106107011801 40.352 –107.022

233 SB00508630CCC1 USGS 402112107050801 40.353 –107.086

234 SB00508636BAA2 USGS 402113106590501 40.354 –106.985

235 SB00508629CDD1 USGS 402114107034300 40.354 –107.063

236 SB00508629CDD2 USGS 402114107034301 40.354 –107.063

237 SB00508629DCC1 USGS 402118107033101 40.355 –107.059

238 SB00508526CCC1 USGS 402120106535201 40.356 –106.898

239 SB00408525DDD1 USGS 402121106515301 40.356 –106.865

240 SB00508629DDB USGS 402124107031801 40.357 –107.056

241 SB00508625DDB1 USGS 402128106583901 40.358 –106.978

242 SB00508525DAD1 USGS 402132106515001 40.359 –106.864

243 SB00508527ACC1 USGS 402146106543401 40.363 –106.910

244 SB00508627BCA1 USGS 402149107013801 40.364 –107.028

245 SB00508627BBC1 USGS 402156107015201 40.366 –107.032

246 SB00508527ABC1 USGS 402157106543101 40.366 –106.909

247 SB00508025AAC1 USGS 402157106583801 40.366 –106.978

248 SB00408529BAC1 USGS 402158106570701 40.366 –106.953

249 SB00508628ABB1 USGS 402202107022101 40.367 –107.040

250 SB00508809CDB1 USGS 402202107160801 40.367 –107.270

251 SB00508627BAA USGS 402204107012201 40.368 –107.023

252 SB00508628BAA1 USGS 402204107022801 USGS 402204107022801 40.368 –107.042

253 SB00508627BAB1 USGS 402205107013201 40.368 –107.026

254 SB00508621CDD USGS 402209107023101 40.369 –107.043

255 SB00508622DCC1 USGS 402212107011801 USGS 402212107011801 40.370 –107.022

256 SB005087019CDA2 USGS 402217107113601 40.371 –107.194

257 SB00508719CDA1 USGS 402222107113001 40.373 –107.192

258 SB00508719ABA2 USGS 402231107111601 40.382 –107.188

259 SB00508719ABA1 USGS 402231107111602 40.382 –107.188

260 SB00508720BBA2 USGS 402231107111612 40.382 –107.179

261 SB00508717BCC1 USGS 402231107111616 40.392 –107.179

262 SB00508717ADC1 USGS 402231107111617 40.392 –107.166

263 SB00508719ABB1 USGS 402231107111630 40.382 –107.189

264 SB00508719ABB2 USGS 402231107111631 40.382 –107.189

265 SB00508719ABB3 USGS 402231107111632 40.382 –107.189

266 SB00508719ABB4 USGS 402231107111633 40.382 –107.189

267 SB00508719DBA3 USGS 402231107111634 40.375 –107.188

268 SB00508719DBA5 USGS 402231107111636 40.375 –107.188

269 SB00508719DBA6 USGS 402231107111637 40.375 –107.188

270 SB00508718CAC1 USGS 402231107111646 40.388 –107.196

271 SB00508719CCB3 USGS 402231107111653 40.376 –107.194

272 SB00508719CDC2 USGS 402231107111657 40.369 –107.195

273 SB00508621BCC USGS 402236107025301 40.377 –107.049

274 SB00508523ADC1 USGS 402237106530701 40.377 –106.886

275 SB00508620BCB USGS 402239107040301 40.377 –107.068

276 SB00508820ACA1 USGS 402244107165001 40.379 –107.281

277 SB00508822BBC1 USGS 402250107151801 USGS 402250107151801 40.381 –107.256

278 SB00508822BBC1 USGS 402250107151802 USGS 402250107151802 40.381 –107.256

279 SB00508621AAA USGS 402257107015301 40.382 –107.032

280 SB00508420BAB1 USGS 402259106501501 40.383 –106.838
Appendix 5 115

Appendix 5. Description of selected groundwater sampling sites in the Upper Yampa River watershed, Colorado, with geologic unit 

description, type of water-quality data collected, period of water-quality record, number of samples collected, and constituents with 

exceedances of Colorado Department of Public Health and Environment water-quality standards for groundwater, 1975 through 1989 

and 1998.—Continued

[No., number; CDPHE, Colorado Department of Public Health and Environment; USGS, U.S. Geological Survey; PP, physical properties; --, water-quality 

standard not exceeded; DS, dissolved solids; MI, major ions; N, nutrients; TE, trace elements; Fe, iron; Mn, manganese; NO3+NO2, nitrate plus nitrite; Zn, zinc; 

Sul, sulfate; Cd, cadmium; Ar, arsenic; R, radiochemical; Chl, chloride; Bo, boron; Pb, lead; SI, stable isotopes; OC, organic carbon; Fl, fluoride; Be, beryllium; 

Cu, copper; Se, selenium; Mo, molybdenum; CDOA, Colorado Department of Agriculture. The Upper Yampa River water-quality database is available at 

http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml]

Site no.

(see figure 15) Geologic unit description Type of water-quality data collected1

Period of waterquality record 

(calendar year)

No. of 

sample 

days

No. of

samples2

Constituent with 

exceedance of CDPHE 

water-quality standard3

230 Unknown PP, DS, MI, N, TE 1975 1 1 --

231 Mesaverde Group PP, DS, MI, N, TE 1975, 1978 3 3 --

232 Lewis Shale PP 1975 1 1 --

233 Unknown PP, DS, MI, N, TE 1975 2 2 --

234 Mesaverde Group PP, DS, MI, N, TE 1980 1 1 --

235 Mesaverde Group PP, DS, MI, N, TE 1975 1 1 --

236 Mesaverde Group PP, DS, MI, N, TE 1975, 1977 2 2 pH, Cd

237 Mesaverde Group PP, DS, MI, N, TE 1975 2 2 --

238 Alluvium, flood plain PP, DS, MI, N, TE 1975 2 2 Ar

239 Browns Park Formation PP 1978 1 1 --

240 Mesaverde Group PP, DS, MI, N, TE 1975 2 2 Sul

241 Unknown PP 1975 1 1 --

242 Browns Park Formation PP 1978 1 1 --

243 Alluvium, flood plain PP 1978 1 1 --

244 Lewis Shale PP 1975 1 1 --

245 Lewis Shale PP, DS, MI, N, TE 1975 2 2 Fe, Mn

246 Alluvium, flood plain PP 1975 1 1 --

247 Unknown PP 1975 1 1 --

248 Mancos Shale PP 1978 1 1 --

249 Alluvium, flood plain PP, DS, MI, N, TE 1975 2 2 Mn

250 Alluvium, flood plain PP 1975 1 1 --

251 Alluvium, flood plain PP, DS, MI, N, TE 1976, 1980 3 3 NO3

+NO2, Fe, Mn (2)

252 Mesaverde Group PP, DS, MI, N, TE 1975 1 1 --

253 Lewis Shale PP, DS, MI, N, TE 1975 2 2 Mn

254 Mesaverde Group PP, DS, MI, N, TE 1976–77, 1980 3 3 pH (2), Cd

255 Valley-fill deposits PP, DS, MI, N, TE 1975 1 1 --

256 Mesaverde Group PP 1978 1 1 --

257 Unknown PP, DS, MI, N, TE 1975 2 2 Sul, Fe, Mn

258 Mesaverde Group PP, DS, MI, N, TE, R 1980–81 4 4 Sul (4), Fe (2), Mn (3)

259 Mesaverde Group PP, DS, MI, N, TE, R 1980–83 9 9 Sul (2)

260 Mesaverde Group PP, DS, MI, N, TE, R 1980–83 9 9 pH (2), Mn (6)

261 Unknown PP, DS, MI, N, TE, R 1980–82 7 7 Mn (6)

262 Unknown PP, DS, MI, N, TE, R 1980–82 5 5 Fe (2), Mn (5)

263 Unknown PP, DS, MI, N, TE 1981 1 1 Sul, Mn

264 Unknown PP, DS, MI, N, TE 1981 1 1 Sul, Mn

265 Unknown PP, DS, MI, N, TE 1981 1 1 Sul, Mn

266 Unknown PP, DS, MI, N, TE 1981 1 1 Sul, Mn

267 Unknown PP, DS, MI, N, TE, R 1980–83 9 9 Sul (4), Fe, Mn (8)

268 Unknown PP, DS, MI, N, TE, R 1980–82 6 6 pH (5), Chl (6), Fe, Mn

269 Unknown PP, DS, MI, N, TE, R 1982–83 7 7 pH (4), Sul (5), Chl (2)

270 Unknown PP, DS, MI, N, TE, R 1980–83 12 12 Sul (4), Mn (2)

271 Unknown PP, DS, MI, N, TE, R 1981–82 6 6 Sul (6), Fe, Mn (6)

272 Unknown PP, DS, MI, N, TE, R 1980–82 6 6 Fe (2), Mn (4)

273 Mesaverde Group PP, DS, MI, N, TE 1976–77, 1980 3 3 Sul, Chl (2), Bo

274 Browns Park Formation PP 1978 1 1 --

275 Mesaverde Group PP, DS, MI, N, TE 1976–77 2 2 --

276 Unknown PP, DS, MI, N, TE, R 1980–81 4 4 Fe, Mn (3)

277 Mesaverde Group PP, DS, MI, N, TE 1975 1 1 Fe, Zn

278 Unknown PP 1975 1 1 --

279 Mesaverde Group PP, DS, MI, N, TE 1976–77, 1980 3 3 pH (2)

280 Browns Park Formation PP 1978 1 1 --
116 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Appendix 5. Description of selected groundwater sampling sites in the Upper Yampa River watershed, Colorado, with geologic unit 

description, type of water-quality data collected, period of water-quality record, number of samples collected, and constituents with 

exceedances of Colorado Department of Public Health and Environment water-quality standards for groundwater, 1975 through 1989 

and 1998.—Continued

[No., number; CDPHE, Colorado Department of Public Health and Environment; USGS, U.S. Geological Survey; PP, physical properties; --, water-quality 

standard not exceeded; DS, dissolved solids; MI, major ions; N, nutrients; TE, trace elements; Fe, iron; Mn, manganese; NO3+NO2, nitrate plus nitrite; Zn, zinc; 

Sul, sulfate; Cd, cadmium; Ar, arsenic; R, radiochemical; Chl, chloride; Bo, boron; Pb, lead; SI, stable isotopes; OC, organic carbon; Fl, fluoride; Be, beryllium; 

Cu, copper; Se, selenium; Mo, molybdenum; CDOA, Colorado Department of Agriculture. The Upper Yampa River water-quality database is available at 

http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml]

Site no.

(see figure 15)

Site name in Upper Yampa River watershed 

water-quality database

Source 

of data Site Identifier Latitude Longitude

281 SB00508915CAB USGS 402303107215701 40.384 –107.366

282 SB00508913ACC USGS 402316107182301 40.388 –107.307

283 SB00508416DBB1 USGS 402324106485701 40.390 –106.816

284 SB00508515CBA1 USGS 402324106545501 40.390 –106.916

285 SB00508613ACC FOIDEL-MIDDLE CRK 5 USGS 402327106590000 40.391 –106.984

286 SB00508613ACC USGS 402327106590001 40.391 –106.984

287 SB00508816CAB1 USGS 402327107161301 40.391 –107.271

288 SB00508515ADC1 USGS 402329106541001 40.391 –106.903

289 SB00508518ACA1 USGS 402334106574601 40.393 –106.963

290 SB00508518ACA USGS 402336106574400 40.393 –106.963

291 SB00508417BCB RICHARD RUBISH USGS 402338106503600 40.394 –106.844

292 SB00508912CCD1 USGS 402344107195001 40.396 –107.331

293 SB00508613ABB FOIDEL MIDDLE CRK 6 USGS 402346106590000 40.396 –106.984

294 SB00508613ABB USGS 402346106590001 40.396 –106.984

295 SB00508514BBB1 USGS 402349106535201 40.397 –106.898

296 SB00508516AAA1 USGS 402351106482201 40.397 –106.807

297 SB00508808CDC USGS 402356107171701 40.399 –107.289

298 SB00508511CCC1 USGS 402357106535801 40.399 –106.900

299 SB00508511CCC BETTY PUGH USGS 402358106535900 40.399 –106.900

300 SCL287 USGS 402359107054401 40.400 –107.096

301 SCI287 USGS 402359107054402 40.400 –107.096

302 SCW287 USGS 402359107054403 40.400 –107.096

303 SCU287 USGS 402359107054404 40.400 –107.096

304 SCS1487-62 USGS 402401107054701 40.400 –107.097

305 SCS2487-63 USGS 402401107054702 40.400 –107.097

306 SCS3487-64 USGS 402401107054703 40.400 –107.097

307 SB00508612DBB1 USGS 402414106585701 USGS 402414106585701 40.404 –106.983

308 SB00508807CBB1 USGS 402415107184401 40.404 –107.313

309 SB00508509ADC GARY BRENNEMAN USGS 402423106552500 40.406 –106.924

310 SB00508407ABD1 USGS 402436106510101 40.410 –106.851

311 SBL287 USGS 402437107051701 40.410 –107.089

312 SBI287 USGS 402437107051702 40.410 –107.089

313 SBW287 USGS 402437107051703 40.410 –107.089

314 SBU287 USGS 402437107051704 40.410 –107.089

315 SB00500508BBC1 USGS 402438106572001 40.411 –106.956

316 SB00508612BAC USGS 402440106591001 40.411 –106.987

317 SSL287 USGS 402454107071601 40.415 –107.122

318 SSI287 USGS 402454107071602 40.415 –107.122

319 SSW287 USGS 402454107071603 40.415 –107.122

320 SSU487 USGS 402454107071604 40.415 –107.122

321 SSU187 USGS 402454107071605 40.415 –107.122

322 SSD487 USGS 402454107071606 40.415 –107.122

323 SZL287 USGS 402455107073001 40.415 –107.126

324 SZI287 USGS 402455107073002 40.415 –107.126

325 SZW487 USGS 402455107073003 40.415 –107.126

326 SZU287 USGS 402455107073004 40.415 –107.126

327 SSS1487-59 USGS 402456107071101 40.416 –107.120
Appendix 5 117

Appendix 5. Description of selected groundwater sampling sites in the Upper Yampa River watershed, Colorado, with geologic unit 

description, type of water-quality data collected, period of water-quality record, number of samples collected, and constituents with 

exceedances of Colorado Department of Public Health and Environment water-quality standards for groundwater, 1975 through 1989 

and 1998.—Continued

[No., number; CDPHE, Colorado Department of Public Health and Environment; USGS, U.S. Geological Survey; PP, physical properties; --, water-quality 

standard not exceeded; DS, dissolved solids; MI, major ions; N, nutrients; TE, trace elements; Fe, iron; Mn, manganese; NO3+NO2, nitrate plus nitrite; Zn, zinc; 

Sul, sulfate; Cd, cadmium; Ar, arsenic; R, radiochemical; Chl, chloride; Bo, boron; Pb, lead; SI, stable isotopes; OC, organic carbon; Fl, fluoride; Be, beryllium; 

Cu, copper; Se, selenium; Mo, molybdenum; CDOA, Colorado Department of Agriculture. The Upper Yampa River water-quality database is available at 

http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml]

Site no.

(see figure 15) Geologic unit description Type of water-quality data collected1

Period of waterquality record 

(calendar year)

No. of 

sample 

days

No. of

samples2

Constituent with 

exceedance of CDPHE 

water-quality standard3

281 Unknown PP, DS, MI, N, TE 1980 1 1 Sul, Fe

282 Unknown PP, DS, MI, N, TE 1980 1 1 --

283 Alluvium, flood plain PP 1978 1 1 --

284 Browns Park Formation PP 1978 1 1 --

285 Unknown PP, DS, MI, N, TE 1975 1 1 Fe

286 Mesaverde Group PP, DS, MI, N, TE 1977 1 1 Chl, Pb

287 Unknown PP, DS, MI, N, TE, R 1980–81 4 4 Sul (4), Fe (3), Mn (4)

288 Browns Park Formation PP 1978 1 1 --

289 Mesaverde Group PP 1978 1 1 --

290 Unknown PP, DS, MI, N, TE 1975 1 1 --

291 Unknown PP, DS, MI, N, TE 1975 1 1 Chl

292 Unknown PP 1975 1 1 --

293 Unknown PP, DS, MI, N, TE 1975 1 1 Sul, Mn

294 Mesaverde Group PP, DS, MI, N, TE 1977 1 1 pH, Sul

295 Browns Park Formation PP 1978 1 1 --

296 Alluvium, flood plain PP 1978 1 1 --

297 Unknown PP, DS, MI, N, TE 1976–77 2 2 pH, Sul (2), Fe

298 Browns Park Formation PP 1978 1 1 --

299 Unknown PP, DS, MI, N, TE 1975 1 1 --

300 Unknown PP, DS, MI, N, TE 1987–89 9 9 Sul (9), Fe (3), Mn (9)

301 Unknown PP, DS, MI, N, TE 1987–89 9 9 Sul (7), Mn (2)

302 Unknown PP, DS, MI, N, TE, R, SI 1987–89 9 9 pH (2), Sul (8), Mn (2)

303 Unknown PP, DS, MI, N, TE, OC, R, SI 1987–89 10 11 pH (5), Sul

304 Unknown PP, DS, MI, N, TE, OC, R, SI 1988–89 9 11 Sul (9), NO3

+NO2, Cd, 

Mn (9)

305 Unknown PP, DS, MI, N, TE 1988 4 4 Sul (4), Cd, Mn (4)

306 Unknown PP, DS, MI, N, TE 1987–88 5 5 Sul (5), Mn (5)

307 Mesaverde Group PP, DS, MI, N, TE 1975 1 1 Fe

308 Lewis Shale PP 1978 1 1 --

309 Unknown PP, DS, MI, N, TE 1975 1 1 --

310 Browns Park Formation PP 1978 1 1 --

311 Unknown PP, DS, MI, N, TE 1987–89 12 12 Cd, Fe, Mn (8)

312 Unknown PP, DS, MI, N, TE 1987–89 13 15 Sul (3), NO3

+NO2, Cd, 

Mn (13)

313 Unknown PP, DS, MI, N, TE, R, SI 1987–89 14 15 Mn (10)

314 Unknown PP, DS, MI, N, TE, R, SI 1987–89 12 12 Sul, Mn (8)

315 Browns Park Formation PP 1975 1 1 --

316 Unknown PP, DS, MI, N, TE 1980 1 1 --

317 Unknown PP, DS, MI, N, TE 1987–89 10 12 Sul (10), Fe (2), Mn (10)

318 Unknown PP, DS, MI, N, TE 1987–89 9 9 Sul (9), Cd

319 Unknown PP, DS, MI, N, TE, R, SI 1987–89 9 9 pH, Sul (9), Fe (2), Mn (9)

320 Unknown PP, DS, MI, N, TE, R, SI 1987–89 10 12 Sul (10), Cd, Mn (2)

321 Unknown PP, DS, MI, N, TE, R, SI 1987–89 9 9 pH (8), Sul (5)

322 Unknown PP, DS, MI, N, TE, OC, R, SI 1987–89 9 9 pH (9)

323 Unknown PP, DS, MI, N, TE 1987–89 9 9 pH, Cd

324 Unknown PP, DS, MI, N, TE 1987–89 10 12 pH (7)

325 Unknown PP, DS, MI, N, TE, R, SI 1987–89 6 6 pH (2), Sul (2), Fe, Mn (2)

326 Unknown PP, DS, MI, N, TE, R, SI 1987–89 9 9 pH (3), Fl (2)

327 Unknown PP, DS, MI, N, TE 1987–88 4 4 Sul (4), NO3

+NO2, Cd, 

Mn (4)
118 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Appendix 5. Description of selected groundwater sampling sites in the Upper Yampa River watershed, Colorado, with geologic unit 

description, type of water-quality data collected, period of water-quality record, number of samples collected, and constituents with 

exceedances of Colorado Department of Public Health and Environment water-quality standards for groundwater, 1975 through 1989 

and 1998.—Continued

[No., number; CDPHE, Colorado Department of Public Health and Environment; USGS, U.S. Geological Survey; PP, physical properties; --, water-quality 

standard not exceeded; DS, dissolved solids; MI, major ions; N, nutrients; TE, trace elements; Fe, iron; Mn, manganese; NO3+NO2, nitrate plus nitrite; Zn, zinc; 

Sul, sulfate; Cd, cadmium; Ar, arsenic; R, radiochemical; Chl, chloride; Bo, boron; Pb, lead; SI, stable isotopes; OC, organic carbon; Fl, fluoride; Be, beryllium; 

Cu, copper; Se, selenium; Mo, molybdenum; CDOA, Colorado Department of Agriculture. The Upper Yampa River water-quality database is available at 

http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml]

Site no.

(see figure 15)

Site name in Upper Yampa River watershed 

water-quality database

Source 

of data Site Identifier Latitude Longitude

328 SSS2487-60 USGS 402456107071102 40.416 –107.120

329 SSS3487-61 USGS 402456107071103 40.416 –107.120

330 SB00508804DBC1 USGS 402459107154901 40.416 –107.264

331 SB00508505ADD1 USGS 402514106561501 40.421 –106.938

332 SB00508603ADC1 USGS 402515107005401 40.421 –107.016

333 SB00508601BDA1 USGS 402517106590701 40.421 –106.986

334 SB00508904BBA1 USGS 402526107231601 40.424 –107.388

335 SB00608531CCC1 USGS 402535106582301 USGS 402535106582301 40.426 –106.974

336 SB00608531CCC1 USGS 402535106582501 USGS 402535106582501 40.426 –106.974

337 SB00608932DDB USGS 402535107234401 40.426 –107.396

338 SB00508503BBB1 USGS 402545106481901 40.429 –106.806

339 SB6N87W34DDB1 USGS 402545107073901 40.429 –107.128

340 SB00608431DDB1 USGS 402551106505201 40.431 –106.848

341 SB00608833DBB USGS 402600107160001 40.433 –107.267

342 SB00608836BDC1 USGS 402609107124801 40.436 –107.214

343 SB00608734ADA1 USGS 402620107072928 40.437 –107.127

344 SB00608734ADA2 USGS 402620107072929 40.437 –107.128

345 SB00608734ADB3 USGS 402620107072930 40.437 –107.128

346 SB00608734ACA1 USGS 402620107072932 40.438 –107.131

347 SB00608734ACA2 USGS 402620107072933 40.437 –107.130

348 SB00508703DAC1 USGS 402620107072935 40.418 –107.128

349 SB00608722DDD1 GW-S21,NW OF FLY ASHPIT USGS 402620107072939 40.456 –107.128

350 SB00608734DDB1 USGS 402620107072950 40.430 –107.129

351 SB00608734DDB2 USGS 402620107072951 40.430 –107.125

352 SB00508703DAA1 USGS 402620107072952 40.420 –107.119

353 SB00508711BDB1 USGS 402620107072953 40.408 –107.119

354 SB00508711BDB2 USGS 402620107072955 40.408 –107.119

355 SB00608734BAB1 AW-1SENECA USGS 402620107072956 40.441 –107.138

356 SB00608731BBB JIM ROWLEY USGS 402627107115900 40.441 –107.200

357 SB00608433BAD CYRIL BARBER USGS 402631106485700 40.442 –106.816

358 SB00608727DCA USGS 402633107080101 40.442 –107.134

359 SB00608429DDD LOY ARDREY USGS 402639106493600 40.444 –106.827

360 SB00608728DCA1 USGS 402641107090201 40.445 –107.151

361 SB00608828DAD1 USGS 402643107153301 40.445 –107.260

362 SB00608625DBC1 USGS 402646106585501 40.446 –106.983

363 SB00608625DBD ARNOLD LIESKE USGS 402647106585000 40.446 –106.981

364 SB00608625BDB1 USGS 402709106591201 40.452 –106.987

365 SB00608930BAB1 USGS 402709107252501 40.452 –107.424

366 SB00608625BAC1 USGS 402710106591401 40.453 –106.988

367 SB00608720AAC1 USGS 402804107095201 40.468 –107.165

368 SB00608623ABA1 USGS 402809106595501 40.469 –106.999

369 SB00608509DDD1 USGS 402810106551001 USGS 402810106551001 40.469 –106.920

370 SB00608623BBA1 USGS 402815107003001 40.471 –107.009

371 SB00608813ADD2 USGS 402842107120001 40.478 –107.201

372 SB00608815BDC1 USGS 402843107150601 40.479 –107.252

373 SB00608815BCD1 USGS 402843107151201 40.479 –107.254

374 SB00608813ADD1 USGS 402845107115901 40.479 –107.200

375 SB00608814ADA1 USGS 402852107125801 40.481 –107.217

376 SB00608813ABC1 USGS 402857107122601 40.482 –107.208
Appendix 5 119

Appendix 5. Description of selected groundwater sampling sites in the Upper Yampa River watershed, Colorado, with geologic unit 

description, type of water-quality data collected, period of water-quality record, number of samples collected, and constituents with 

exceedances of Colorado Department of Public Health and Environment water-quality standards for groundwater, 1975 through 1989 

and 1998.—Continued

[No., number; CDPHE, Colorado Department of Public Health and Environment; USGS, U.S. Geological Survey; PP, physical properties; --, water-quality 

standard not exceeded; DS, dissolved solids; MI, major ions; N, nutrients; TE, trace elements; Fe, iron; Mn, manganese; NO3+NO2, nitrate plus nitrite; Zn, zinc; 

Sul, sulfate; Cd, cadmium; Ar, arsenic; R, radiochemical; Chl, chloride; Bo, boron; Pb, lead; SI, stable isotopes; OC, organic carbon; Fl, fluoride; Be, beryllium; 

Cu, copper; Se, selenium; Mo, molybdenum; CDOA, Colorado Department of Agriculture. The Upper Yampa River water-quality database is available at 

http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml]

Site no.

(see figure 15) Geologic unit description Type of water-quality data collected1

Period of waterquality record 

(calendar year)

No. of 

sample 

days

No. of

samples2

Constituent with 

exceedance of CDPHE 

water-quality standard3

328 Unknown PP, DS, MI, N, TE 1987–88 5 5 Sul (5), NO3+NO2 (3), Cd, 

Mn (5)

329 Unknown PP, DS, MI, N, TE, OC, R, SI 1987–89 10 12 Sul (10), NO3

+NO2 (5), 

Be (2), Cd, Mn (10)

330 Unknown PP, DS, MI, N, TE 1975 2 2 Sul, Mn

331 Browns Park Formation PP, DS, MI, N, TE 1978 1 1 NO3

+NO2

332 Mesaverde Group PP, MI, N, TE 1980 1 1 pH

333 Alluvium, flood plain PP 1978 1 1 pH

334 Unknown PP, DS, MI, N, TE 1975 2 2 Sul, Fe, Mn

335 Alluvium, flood plain PP 1978 1 1 pH

336 Alluvium, flood plain PP 1978 1 1 pH

337 Unknown PP 1975 1 1 --

338 Browns Park Formation PP 1978 1 1 pH

339 Mesaverde Group PP, DS, MI, N, TE 1977 1 1 pH, Sul

340 Browns Park Formation PP 1977 1 1 --

341 Unknown PP, DS, MI, N, TE 1976–77 3 3 pH (2), Fe

342 Mesaverde Group PP, DS, MI, N, TE 1978 1 1 NO3

+NO2

343 Mesaverde Group PP, DS, MI, N, TE, R 1980–81, 1983 6 6 Sul (6), Bo (2), Fe, Mn (5)

344 Mesaverde Group PP, DS, MI, N, TE, R 4

1980–86 12 12 pH, Sul (12), Mn (11)

345 Mesaverde Group PP, DS, MI, N, TE, R 4

1980–86 13 13 pH, Sul (13), Mn (12)

346 Mesaverde Group PP, DS, MI, TE 1984 1 1 Sul

347 Mesaverde Group PP, DS, MI, N, TE, R 4

1979–86 14 14 pH (3), Sul (14), Mn (5)

348 Mesaverde Group PP, DS, MI, N, TE 1979–80 2 2 pH (2)

349 Unknown PP, DS, MI, N, TE 1980 1 1 Sul, Mn

350 Mesaverde Group PP, DS, MI, N, TE, R 1979–82 6 6 Sul

351 Mesaverde Group PP, DS, MI, N, TE, R 1979–82 5 5 pH, Sul (4), Fe (2), Mn (5)

352 Mesaverde Group PP, DS, MI, N, TE, OC, R 1979–83 10 10 pH

353 Unknown PP, DS, MI, N, TE, R 1979–82 6 6 --

354 Unknown PP, DS, MI, TE 1979 1 1 pH

355 Unknown PP, DS, MI, N, TE, R 1980–83 8 8 pH, Sul (6), Fe (4), Mn (8)

356 Unknown PP, DS, MI, N, TE 1975 1 1 Mn

357 Valley-fill deposits PP, DS, MI, N, TE 1975 1 1 --

358 Valley-fill deposits PP, DS, MI, N, TE 1975 2 2 Sul, Cu

359 Valley-fill deposits PP, DS, MI, N, TE 1975 1 1 --

360 Unknown PP 1975 1 1 --

361 Lewis Shale PP, DS, MI, N, TE 1975 2 2 --

362 Alluvium, flood plain PP 1975 1 1 --

363 Unknown PP, DS, MI, N, TE 1975 1 1 Fe, Mn

364 Unknown PP, DS, MI, N, TE 1975 2 2 --

365 Unknown PP, DS, MI, N, TE 1975 1 1 --

366 Mesaverde Group PP 1978 1 1 --

367 Lewis Shale PP 1975 1 1 --

368 Mesaverde Group PP 1978 1 1 --

369 Mancos Shale PP, DS, MI, N, TE 1978 1 1 Fe

370 Unknown PP 1975 1 1 --

371 Lewis Shale PP, DS, MI, N, TE 1978–79 3 3 --

372 Lewis Shale PP 1979 1 1 --

373 Lewis Shale PP 1975 1 1 --

374 Lewis Shale PP 1975 1 1 --

375 Lewis Shale PP, DS, MI, N, TE 1975 1 1 NO3

+NO2

376 Unknown PP 1975 1 1 --
120 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Appendix 5. Description of selected groundwater sampling sites in the Upper Yampa River watershed, Colorado, with geologic unit 

description, type of water-quality data collected, period of water-quality record, number of samples collected, and constituents with 

exceedances of Colorado Department of Public Health and Environment water-quality standards for groundwater, 1975 through 1989 

and 1998.—Continued

[No., number; CDPHE, Colorado Department of Public Health and Environment; USGS, U.S. Geological Survey; PP, physical properties; --, water-quality 

standard not exceeded; DS, dissolved solids; MI, major ions; N, nutrients; TE, trace elements; Fe, iron; Mn, manganese; NO3+NO2, nitrate plus nitrite; Zn, zinc; 

Sul, sulfate; Cd, cadmium; Ar, arsenic; R, radiochemical; Chl, chloride; Bo, boron; Pb, lead; SI, stable isotopes; OC, organic carbon; Fl, fluoride; Be, beryllium; 

Cu, copper; Se, selenium; Mo, molybdenum; CDOA, Colorado Department of Agriculture. The Upper Yampa River water-quality database is available at 

http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml]

Site no.

(see figure 15)

Site name in Upper Yampa River watershed 

water-quality database

Source 

of data Site Identifier Latitude Longitude

377 SB00608817BBC1 USGS 402857107174201 40.482 –107.296

378 SB00608717BAD1 USGS 402858107102501 40.483 –107.174

379 SB00608514BBC1 USGS 402902106470401 40.484 –106.785

380 SB00608717BAA1 USGS 402902107101801 40.484 –107.172

381 SB00608614ABA1 USGS 402904106595701 40.484 –107.000

382 SB00608011AAA1 USGS 402906107040801 40.485 –107.069

383 SB00608912DDD1 USGS 402906107185401 40.485 –107.316

384 SB00608509DDD1 USGS 402907106550300 USGS 402907106550300 40.485 –106.918

385 SB00608615BAA1 USGS 402908107011901 40.486 –107.023

386 SB00608708CCD1 USGS 402908107103701 40.486 –107.178

387 SB00608609DCD1 USGS 402912107020901 40.487 –107.036

388 SB00608707DCC1 USGS 402912107112401 40.487 –107.191

389 SB00608611DDD1 USGS 402913107051501 40.487 –107.088

390 SB00608708CCD2 USGS 402913107103701 40.487 –107.178

391 SB00608811DDC1 USGS 402913107132101 40.487 –107.223

392 SB00508612DBB1 USGS 402914106585701 USGS 402914106585701 40.487 –106.983

393 SB00608712DDA USGS 402916107061601 40.488 –107.105

394 SB00608808DCB1 USGS 402917107170101 40.488 –107.284

395 SB00608509DAD1 USGS 402920106550701 40.489 –106.919

396 SB00608809CBD1 USGS 402920107154301 40.489 –107.263

397 SB00608708CBD1 USGS 402921107104001 40.489 –107.178

398 SB00608708CBD2 USGS 402922107104001 40.489 –107.178

399 SB00608511CAD1 USGS 402924106532301 40.490 –106.890

400 SB00608707DBC1 USGS 402924107112001 40.490 –107.190

401 SB00608707DBC2 USGS 402924107112201 40.490 –107.190

402 SB00608609DAB1 USGS 402929107015901 40.491 –107.034

403 SB00608707DAB1 USGS 402929107110301 40.491 –107.185

404 SB00608807DBB1 USGS 402929107181701 40.491 –107.305

405 SB00608707DAA1 USGS 402930107105101 40.492 –107.181

406 SB00608707DAA2 USGS 402930107105201 40.492 –107.182

407 SB00608911DBB1 USGS 402930107203001 40.492 –107.342

408 SB00608508CAB1 USGS 402931106565501 40.492 –106.949

409 SB00608609DBA1 USGS 402931107020901 40.492 –107.036

410 SB00608911ACC1 USGS 402931107203001 40.492 –107.342

411 SB00608707ADC1 USGS 402932107110101 40.492 –107.184

412 SB00608707DBB1 USGS 402932107112001 40.492 –107.190

413 SB00608808CAB USGS 402932107171801 40.492 –107.289

414 SB00608707ADC2 USGS 402933107110201 40.492 –107.185

415 SB00608707ADC3 USGS 402933107110701 40.492 –107.186

416 SB00608707ADC4 USGS 402933107110702 40.492 –107.186

417 SB00608707ACD1 USGS 402933107111301 40.492 –107.188

418 SB00608707ACC1 USGS 402933107112201 40.492 –107.190

419 SB00608707ACD2 USGS 402934107111301 40.493 –107.188

420 SB00608707ADD1 USGS 402935107105301 40.493 –107.182

421 SB00608707ACD3 USGS 402937107111401 40.494 –107.188

422 SB00608809ACD1 USGS 402938107155201 40.494 –107.265

423 SB00608912ADA1 USGS 402938107185201 40.494 –107.315

424 SB00608512BCA1 USGS 402941106523101 40.495 –106.876

425 SB00608809ADA1 USGS 402942107152501 40.495 –107.258

426 SB00608809ACA1 USGS 402942107154401 40.495 –107.263

427 SB00608510ACA1 USGS 402944106541301 40.496 –106.904
Appendix 5 121

Appendix 5. Description of selected groundwater sampling sites in the Upper Yampa River watershed, Colorado, with geologic unit 

description, type of water-quality data collected, period of water-quality record, number of samples collected, and constituents with 

exceedances of Colorado Department of Public Health and Environment water-quality standards for groundwater, 1975 through 1989 

and 1998.—Continued

[No., number; CDPHE, Colorado Department of Public Health and Environment; USGS, U.S. Geological Survey; PP, physical properties; --, water-quality 

standard not exceeded; DS, dissolved solids; MI, major ions; N, nutrients; TE, trace elements; Fe, iron; Mn, manganese; NO3+NO2, nitrate plus nitrite; Zn, zinc; 

Sul, sulfate; Cd, cadmium; Ar, arsenic; R, radiochemical; Chl, chloride; Bo, boron; Pb, lead; SI, stable isotopes; OC, organic carbon; Fl, fluoride; Be, beryllium; 

Cu, copper; Se, selenium; Mo, molybdenum; CDOA, Colorado Department of Agriculture. The Upper Yampa River water-quality database is available at 

http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml]

Site no.

(see figure 15) Geologic unit description Type of water-quality data collected1

Period of waterquality record 

(calendar year)

No. of 

sample 

days

No. of

samples2

Constituent with 

exceedance of CDPHE 

water-quality standard3

377 Alluvium, flood plain PP 1975 1 1 --

378 Alluvium, terrace PP, DS, MI, N, TE 1979 5 5 Bo (3), Mn (2), Se

379 Alluvium, terrace PP 1978 1 1 --

380 Alluvium, terrace PP, DS, MI, N, TE 1978–79 6 6 Sul (2), Fe, Mn (3)

381 Alluvium, flood plain PP 1978 1 1 pH

382 Alluvium, flood plain PP 1975 1 1 --

383 Alluvium, flood plain PP 1975 1 1 --

384 Unknown PP 1975 1 1 --

385 Alluvium, flood plain PP 1975 1 1 --

386 Alluvium, terrace PP, DS, MI, N, TE 1978–79 8 8 Bo, Mn

387 Alluvium, flood plain PP 1978 1 1 pH

388 Alluvium, terrace PP, DS, MI, N, TE 1978–79 6 6 NO3

+NO2 (3), Mn

389 Alluvium, flood plain PP 1975 1 1 --

390 Alluvium, terrace PP, DS, MI, N, TE 1978–79 6 6 Bo (3), Mn (2)

391 Lewis Shale PP 1978 1 1 pH

392 Unknown PP 1975 1 1 --

393 Mesaverde Group PP, DS, MI, N, TE 1975 1 1 --

394 Alluvium, flood plain PP 1975 1 1 --

395 Mancos Shale PP 1978 1 1 --

396 Alluvium, flood plain PP 1978 1 1 --

397 Alluvium, terrace PP, DS, MI, N, TE 1978–79 6 6 Sul, Bo (4), Mn

398 Alluvium, terrace PP, DS, MI, N, TE 1978–79 5 5 Sul, Bo (4), Mn (3)

399 Browns Park Formation PP, DS, MI, N, TE 1978 1 1 pH

400 Alluvium, terrace PP, DS, MI, N, TE 1978–79 5 5 Bo (4), Mn (2)

401 Alluvium, terrace PP, DS, MI, N, TE 1978–79 6 6 Sul, Bo (4), Mn

402 Mesaverde Group PP 1978 1 1 pH

403 Alluvium, terrace PP, DS, MI, N, TE 1978–79 4 4 Sul (2), Bo (2), Mn (2)

404 Alluvium, flood plain PP 1975 1 1 --

405 Alluvium, terrace PP, DS, MI, N, TE 1978–79 5 5 Sul (2), Bo (4), Mn (3)

406 Alluvium, terrace PP, DS, MI, N, TE 1978–79 6 6 Sul (2), Bo (4), Mn

407 Upper Cretaceous series PP 1978 1 1 --

408 Alluvium, flood plain PP 1975 1 1 --

409 Alluvium, flood plain PP 1975 1 1 --

410 Alluvium, flood plain PP 1975 1 1 --

411 Alluvium, terrace PP, DS, MI, N, TE 1978–79 5 5 Bo (3), Mn (2)

412 Alluvium, terrace PP, DS, MI, N, TE 1978–79 5 5 Sul (2), Bo (4)

413 Alluvium, flood plain PP, DS, MI, N, TE 1975 2 2 Sul, Fe, Mn

414 Alluvium, terrace PP, DS, MI, N, TE 1978–79 5 5 Bo (2), Mn (2)

415 Alluvium, terrace PP, DS, MI, N, TE 1978–79 5 5 Sul (2), Bo (3), Mn (3)

416 Alluvium, terrace PP, DS, MI, N, TE 1978–79 5 5 Sul (2), Bo (3), Fe, Mn (4)

417 Alluvium, terrace PP, DS, MI, N, TE 1978–79 5 5 Sul (2), Bo (4), Mn (2)

418 Alluvium, terrace PP, DS, MI, N, TE 1978–79 6 6 Sul (2), Bo (3)

419 Alluvium, terrace PP, DS, MI, N, TE 1978–79 6 6 Sul (2), Bo (4), Mn (2)

420 Alluvium, terrace PP, DS, MI, N, TE 1978–79 6 6 Bo (2)

421 Alluvium, terrace PP, DS, MI, N, TE 1978–79 5 5 Sul (2), Bo (4), Mn

422 Alluvium, flood plain PP 1978 1 1 --

423 Alluvium, flood plain PP 1975 1 1 --

424 Mancos Shale PP 1978 1 1 --

425 Alluvium, flood plain PP 1978 1 1 --

426 Alluvium, flood plain PP 1978 1 1 --

427 Unknown PP 1975 1 1 --
122 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Appendix 5. Description of selected groundwater sampling sites in the Upper Yampa River watershed, Colorado, with geologic unit 

description, type of water-quality data collected, period of water-quality record, number of samples collected, and constituents with 

exceedances of Colorado Department of Public Health and Environment water-quality standards for groundwater, 1975 through 1989 

and 1998.—Continued

[No., number; CDPHE, Colorado Department of Public Health and Environment; USGS, U.S. Geological Survey; PP, physical properties; --, water-quality 

standard not exceeded; DS, dissolved solids; MI, major ions; N, nutrients; TE, trace elements; Fe, iron; Mn, manganese; NO3+NO2, nitrate plus nitrite; Zn, zinc; 

Sul, sulfate; Cd, cadmium; Ar, arsenic; R, radiochemical; Chl, chloride; Bo, boron; Pb, lead; SI, stable isotopes; OC, organic carbon; Fl, fluoride; Be, beryllium; 

Cu, copper; Se, selenium; Mo, molybdenum; CDOA, Colorado Department of Agriculture. The Upper Yampa River water-quality database is available at 

http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml]

Site no.

(see figure 15)

Site name in Upper Yampa River watershed 

water-quality database

Source 

of data Site Identifier Latitude Longitude

428 SB00608507BCB1 USGS 402946106582101 40.496 –106.973

429 SB00608911BAD1 USGS 402948107203801 40.497 –107.345

430 SB00608509BBC1 USGS 402949106491801 40.497 –106.822

431 SB00608811BAC1 USGS 402949107135201 40.497 –107.232

432 SB00608708BBA1 USGS 402954107103501 40.498 –107.177

433 SB00608708BAB1 USGS 402957107103301 40.499 –107.176

434 SB00608802DDD1 USGS 402959107131101 40.500 –107.220

435 SB00608904CDD1 USGS 402959107222701 40.500 –107.375

436 HS-13 USGS 402960107112401 40.500 –107.191

437 SB00608704DCA1 USGS 403003107224201 40.501 –107.379

438 SB00608503CCC USGS 403004106550001 40.501 –106.917

439 SB00608406CCA1 USGS 403005106512101 40.501 –106.856

440 SB00708503CAD1 USGS 403012106542201 40.503 –106.907

441 SB00608804DBD1 USGS 403014107154701 40.504 –107.264

442 SB00608505DAD1 USGS 403015106561001 40.504 –106.937

443 SB00608501CBC1 USGS 403017106523701 40.505 –106.878

444 SB00608503ADC1 USGS 403025106540101 40.507 –106.901

445 SB00708506CAA1 USGS 403025106575201 40.507 –106.965

446 SB00608705BDD1 USGS 403031107101701 40.509 –107.172

447 SB00608801ADC1 USGS 403031107121601 USGS 403031107121601 40.509 –107.205

448 SB00608801ADC1 USGS 403032107115701 USGS 403032107115701 40.509 –107.205

449 SB00608703ACA1 USGS 403035107075401 40.510 –107.132

450 SB00608904BAB1 USGS 403041107230601 40.511 –107.386

451 SB00608803BAA1 USGS 403047107150701 40.513 –107.253

452 SB00708433CBC1 USGS 403106106492001 40.518 –106.823

453 SB00708731BCB1 USGS 403125107115701 40.524 –107.200

454 SB00708433ABD1 USGS 403127106483501 40.524 –106.810

455 SB00708532BCB1 USGS 403129106570801 40.525 –106.953

456 SB00708827CBC1 USGS 403132107152501 USGS 403132107152501 40.526 –107.258

457 SB00708433BBB1 USGS 403136106491401 40.527 –106.821

458 SB00709025DDD USGS 403143107254501 40.529 –107.430

459 SB00709025CAC1 USGS 403156107262501 40.532 –107.441

460 SB00708428CAD1 USGS 403202106485601 40.534 –106.816

461 SB00708428CBB1 USGS 403205106492001 40.535 –106.823

462 SB00708428CBA1 USGS 403207106490601 40.535 –106.819

463 SB00708525ACC1 USGS 403210106520801 40.536 –106.869

464 SB00708426BCD1 USGS 403211106465401 40.536 –106.782

465 SB00708428ACD1 USGS 403211106484001 40.536 –106.812

466 UNKNOWN USGS 403218106532601 40.538 –106.891

467 SB00708526ACB1 USGS 403219106531101 40.539 –106.887

468 SB00709025BBD1 USGS 403219107263800 40.539 –107.445

469 SB00708525BAD1 USGS 403224106521501 40.540 –106.871

470 SB00708924DDD1 USGS 403233107185801 40.542 –107.317

471 SB00708920CCC1 USGS 403235107243001 40.543 –107.409

472 SB00708525ABD1 USGS 403242106520301 40.545 –106.868

473 SB00708920DCB USGS 403245107235801 40.546 –107.400

474 SB00708523DBB USGS 403258106531300 USGS 403258106531300 40.549 –106.888

475 SB00708924ADD USGS 403303107185600 USGS 403303107185600 40.551 –107.316

476 SB00708829CCD1 USGS 403318107172501 40.555 –107.291

477 SB00708614DAB1 USGS 403351106594201 40.564 –106.996
Appendix 5 123

Appendix 5. Description of selected groundwater sampling sites in the Upper Yampa River watershed, Colorado, with geologic unit 

description, type of water-quality data collected, period of water-quality record, number of samples collected, and constituents with 

exceedances of Colorado Department of Public Health and Environment water-quality standards for groundwater, 1975 through 1989 

and 1998.—Continued

[No., number; CDPHE, Colorado Department of Public Health and Environment; USGS, U.S. Geological Survey; PP, physical properties; --, water-quality 

standard not exceeded; DS, dissolved solids; MI, major ions; N, nutrients; TE, trace elements; Fe, iron; Mn, manganese; NO3+NO2, nitrate plus nitrite; Zn, zinc; 

Sul, sulfate; Cd, cadmium; Ar, arsenic; R, radiochemical; Chl, chloride; Bo, boron; Pb, lead; SI, stable isotopes; OC, organic carbon; Fl, fluoride; Be, beryllium; 

Cu, copper; Se, selenium; Mo, molybdenum; CDOA, Colorado Department of Agriculture. The Upper Yampa River water-quality database is available at 

http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml]

Site no.

(see figure 15) Geologic unit description Type of water-quality data collected1

Period of waterquality record 

(calendar year)

No. of 

sample 

days

No. of

samples2

Constituent with 

exceedance of CDPHE 

water-quality standard3

428 Alluvium, flood plain PP 1975 1 1 --

429 Unknown PP 1975 1 1 --

430 Mancos Shale PP 1978 1 1 --

431 Unknown PP 1975 1 1 --

432 Alluvium, flood plain PP 1975 1 1 --

433 Alluvium, flood plain PP, DS, MI, N, TE 1978 1 1 Fe, Mn

434 Alluvium, flood plain PP 1975 1 1 --

435 Alluvium, flood plain PP 1975 1 1 --

436 Unknown PP, DS, MI, N, TE 1978 1 1 Bo

437 Alluvium, flood plain PP 1975 1 1 --

438 Alluvium, flood plain PP 1975 2 2 --

439 Alluvium, flood plain PP 1978 1 1 --

440 Alluvium, flood plain PP, DS, MI, N, TE 1975 2 2 Mn

441 Alluvium, flood plain PP 1975 1 1 --

442 Unknown PP 1975 1 1 --

443 Alluvium, flood plain PP, DS, MI, N, TE 1975 1 1 Mn

444 Unknown PP 1975 1 1 --

445 Alluvium, flood plain PP, DS, MI, N, TE 1975 2 2 --

446 Alluvium, flood plain PP 1975 1 1 --

447 Alluvium, flood plain PP 1978 1 1 --

448 Valley-fill deposits PP, DS, MI, N, TE 1975, 1978 3 3 Fe

449 Unknown PP 1975 1 1 --

450 Alluvium, flood plain PP 1975 1 1 --

451 Alluvium, flood plain PP 1975 1 1 --

452 Alluvium, flood plain PP, DS, MI, N, TE 1978 1 1 pH

453 Alluvium, flood plain PP 1975 1 1 --

454 Precambrian Erathem PP 1978 1 1 --

455 Mancos Shale PP, DS, MI, N, TE 1975 2 2 pH, Chl, Fl

456 Lewis Shale PP, DS, MI, N, TE 1975 1 1 Sul, NO3

+NO2

457 Browns Park Formation PP 1978 1 1 --

458 Unknown PP 1975 1 1 --

459 Alluvium, flood plain PP 1975 1 1 --

460 Alluvium, flood plain PP 1978 1 1 --

461 Browns Park Formation PP, DS, MI, N, TE 1978 1 1 --

462 Browns Park Formation PP, DS, MI, N, TE 1978 1 1 Fl

463 Alluvium, flood plain PP 1978 1 1 --

464 Precambrian Erathem PP, DS, MI, N, TE 1978 1 1 Fe, Mn

465 Alluvium, flood plain PP 1978 1 1 --

466 Unknown PP, DS, MI, N, TE 1978 1 1 Sul

467 Mancos Shale PP, DS, MI, N, TE 1978 1 1 Fe, Mn, Mo

468 Unknown PP 1975 1 1 --

469 Mancos Shale PP 1978 1 1 --

470 Upper Cretaceous series PP 1978 1 1 --

471 Eocene series PP, DS, MI, N, TE 1975 2 2 --

472 Mancos Shale PP 1978 1 1 --

473 Alluvium, flood plain PP 1975 1 1 --

474 Mancos Shale PP, DS, MI, N, TE 1975 1 1 Chl, Fl

475 Upper Cretaceous series PP, DS, MI, N, TE 1975 1 1 Mn

476 Unknown PP 1975 1 1 --

477 Mancos Shale PP 1978 1 1 --
124 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Appendix 5. Description of selected groundwater sampling sites in the Upper Yampa River watershed, Colorado, with geologic unit 

description, type of water-quality data collected, period of water-quality record, number of samples collected, and constituents with 

exceedances of Colorado Department of Public Health and Environment water-quality standards for groundwater, 1975 through 1989 

and 1998.—Continued

[No., number; CDPHE, Colorado Department of Public Health and Environment; USGS, U.S. Geological Survey; PP, physical properties; --, water-quality 

standard not exceeded; DS, dissolved solids; MI, major ions; N, nutrients; TE, trace elements; Fe, iron; Mn, manganese; NO3+NO2, nitrate plus nitrite; Zn, zinc; 

Sul, sulfate; Cd, cadmium; Ar, arsenic; R, radiochemical; Chl, chloride; Bo, boron; Pb, lead; SI, stable isotopes; OC, organic carbon; Fl, fluoride; Be, beryllium; 

Cu, copper; Se, selenium; Mo, molybdenum; CDOA, Colorado Department of Agriculture. The Upper Yampa River water-quality database is available at 

http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml]

Site no.

(see figure 15)

Site name in Upper Yampa River watershed 

water-quality database

Source 

of data Site Identifier Latitude Longitude

478 SB00708912AAA1 USGS 403504107182701 40.584 –107.308

479 SB007086006DCD1 USGS 403516107042501 40.588 –107.074

480 SB00708505CAA1 USGS 403536106564701 40.593 –106.947

481 SB00708829BCC USGS 403537107162901 40.594 –107.275

482 SB00808933ABD IVAN KAWCAK USGS 403646107223700 40.613 –107.378

483 SB00808529DDD1 USGS 403702106591901 40.617 –106.989

484 SB00808629DAD1 USGS 403711107030101 USGS 403711107030101 40.620 –107.051

485 SB00808629DAD1 USGS 403712107030201 USGS 403712107030201 40.620 –107.051

486 SB00808623CCD1 USGS 403754107002301 40.632 –107.007

487 SB00808520DAC1 USGS 403810106563001 40.636 –106.942

488 SB00808923ADA1 USGS 403820107200001 40.639 –107.334

489 SB00808622BCD1 USGS 403821107013501 40.639 –107.027

490 SB00808519BBA1 USGS 403843106581501 40.645 –106.971

491 SB00808613DDC1 USGS 403843106583501 40.645 –106.977

492 SB00808517DCA1 USGS 403855106563401 40.649 –106.943

493 SB00808517DBC1 USGS 403903106564301 40.651 –106.946

494 SB00808517BDD W C WINTER USGS 403912106565000 40.653 –106.948

495 SB00908527BBC1 USGS 404259106542301 40.716 –106.907

496 SB00908527BBB1 USGS 404302106545201 40.717 –106.915

497 SB00908522CDD USGS 404309106543001 40.719 –106.909

498 SB00908523CCB1 USGS 404318106534201 USGS 404318106534201 40.722 –106.896

499 SB00908513CDC1 USGS 404402106521001 40.734 –106.870

500 SB00908513DAD1 USGS 404414106515101 40.737 –106.865

501 SB00908518ABC1 USGS 404446106574501 40.746 –106.963

502 WS-027CDOA CDOA WS-027 40.19 –106.91

503 WS-029CDOA CDOA WS-029 40.48 –107.02

504 WS-031CDOA CDOA WS-031 40.5 –107.18

505 WS-032CDOA CDOA WS-032 40.49 –107.3

506 WS-033CDOA CDOA WS-033 40.56 –106.89

507 WS-034CDOA CDOA WS-034 40.19 –106.92
Appendix 5 125

Appendix 5. Description of selected groundwater sampling sites in the Upper Yampa River watershed, Colorado, with geologic unit 

description, type of water-quality data collected, period of water-quality record, number of samples collected, and constituents with 

exceedances of Colorado Department of Public Health and Environment water-quality standards for groundwater, 1975 through 1989 

and 1998.—Continued

[No., number; CDPHE, Colorado Department of Public Health and Environment; USGS, U.S. Geological Survey; PP, physical properties; --, water-quality 

standard not exceeded; DS, dissolved solids; MI, major ions; N, nutrients; TE, trace elements; Fe, iron; Mn, manganese; NO3+NO2, nitrate plus nitrite; Zn, zinc; 

Sul, sulfate; Cd, cadmium; Ar, arsenic; R, radiochemical; Chl, chloride; Bo, boron; Pb, lead; SI, stable isotopes; OC, organic carbon; Fl, fluoride; Be, beryllium; 

Cu, copper; Se, selenium; Mo, molybdenum; CDOA, Colorado Department of Agriculture. The Upper Yampa River water-quality database is available at 

http://rmgsc.cr.usgs.gov/cwqdr/Yampa/index.shtml]

Site no.

(see figure 15) Geologic unit description Type of water-quality data collected1

Period of waterquality record 

(calendar year)

No. of 

sample 

days

No. of

samples2

Constituent with 

exceedance of CDPHE 

water-quality standard3

478 Unknown PP 1975 1 1 --

479 Mancos Shale PP, DS, MI, N, TE 1975, 1978 3 3 Zn (2)

480 Mancos Shale PP, DS, MI, N, TE 1978 1 1 Sul, Chl, Fe, Mn

481 Unknown PP 1975 1 1 --

482 Fort Union Formation PP, DS, MI, N, TE 1975 1 1 NO3

+NO2, Fe

483 Alluvium, flood plain PP 1978 1 1 --

484 Alluvium, flood plain PP 1975 1 1 --

485 Alluvium, flood plain PP, DS, MI, N, TE 1978 1 1 --

486 Alluvium, flood plain PP, DS, MI, N, TE 1975 2 2 --

487 Mancos Shale PP, DS, MI, N, TE 1978 1 1 Bo

488 Unknown PP 1975 1 1 --

489 Alluvium, flood plain PP 1975 1 1 --

490 Mancos Shale PP 1978 1 1 --

491 Mancos Shale PP 1978 1 1 --

492 Mancos Shale PP 1978 1 1 --

493 Alluvium, flood plain PP 1978 1 1 pH

494 Valley-fill deposits PP, DS, MI, N, TE 1975 1 1 pH, Fe

495 Mancos Shale PP 1978 1 1 pH

496 Alluvium, flood plain PP 1978 1 1 pH

497 Alluvium, flood plain PP 1978 1 1 --

498 Alluvium, flood plain PP, DS, MI, N, TE 1978 2 2 pH (2)

499 Alluvium, flood plain PP 1978 1 1 pH

500 Alluvium, flood plain PP 1978 1 1 --

501 Browns Park Formation PP, DS, MI, N, TE 1978 1 1 Mn

502 Unknown PP, DS, MI, N 1998 1 1 --

503 Unknown PP, DS, MI, N, TE 1998 1 1 --

504 Unknown PP, DS, MI, N, TE 1998 1 1 --

505 Unknown PP, DS, MI, N, TE 1998 1 1 --

506 Unknown PP, DS, MI, N, TE 1998 1 1 --

507 Unknown PP, DS, MI, N 1998 1 1 -- 1

When multiple samples were collected at a site, all types of water-quality data listed may not be available for each sample.

2

Count does not include samples with water-level measurements only.

3

Number in parentheses is number of exceedances. Except for pH, all standards are for dissolved water samples.

4

Sample collection did not occur in every year of the period of record.
126 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Appendix 6. Description of stream sites in the Upper Yampa River watershed, Colorado, that have macroinvertebrate data, and period 

of water-quality record and number of sample days, 1975 through 2008.—Continued

[No., number; USGS, U.S. Geological Survey; CDPHE, Colorado Department of Public Health and Environment; CSS, City of Steamboat Springs. Subwatershed 

definitions: Yampa River subwatershed 1, Yampa River and tributaries upstream from Chuck Lewis State Wildlife Area; Yampa River subwatershed 2, Yampa River 

and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence; Elk River subwatershed, Elk River and tributaries; Yampa River subwatershed 3, Yampa 

River and tributaries from Elk River confluence to Town of Hayden; Yampa River subwatershed 4, Yampa River and tributaries from Town of Hayden to Elkhead Creek 

confluence; Elkhead Creek subwatershed, Elkhead Creek and tributaries. Sites with the same site number are considered to be at the same location]

Site no.

(see figure 18) Site name Source of data Site identifier

6 BEAR RIVER NEAR TOPONAS, CO USGS 09236000

7 BEAVER CREEK NEAR HAHNS PEAK, CO. USGS 404610106545600

10 BURGESS CK NEAR MOUTH @ HWY 40 CDPHE 12893

180 Bushy Creek above Cty Rd 16 CDPHE 12885

22 DRY CK @ HAYDEN CDPHE 12852

27 ELK R. NEAR MOUTH @ CR44 CDPHE 12860

30 ELK RIVER AT CLARK, CO. USGS 09241000

33 ELK RIVER NEAR MILNER, CO. USGS 09242500

38 ELKHEAD CREEK CDPHE WCOP99-0512

39 ELKHEAD CREEK CDPHE WCOP99-0565

40 ELKHEAD CREEK ABOVE ELKHEAD RESERVOIR, CO. USGS 403530107191300

181 Elkhead Creek above First Creek CDPHE 12849A

182 Elkhead Creek above Rippy property CDPHE 12846A

183 Elkhead Creek at County Rd. 76 CDPHE 12843

184 Elkhead Creek at Rippy property CDPHE 12846

185 Elkhead Creek below Elkhead Reservoir CDPHE 12843A

43 ELKHEAD CREEK NEAR CRAIG, CO USGS 09246500

43 ELKHEAD CK NR CRAIG @ HWY 40 CDPHE 12840

44 ELKHEAD CREEK NEAR ELKHEAD, CO. USGS 09245000

186 First Creek east of USFS/State boundary CDPHE 12849

54 FISH CK NEAR MOUTH @ HWY 40 CDPHE 12870

58 GRASSY CREEK AT GRASSY GAP, CO. USGS 402330107082000

59 GRASSY CREEK NEAR MOUNT HARRIS, CO. USGS 09244300

59 GRASSY CK @ RD. 27A CDPHE 12853

187 Grassy Creek at Rd 27 STL CDPHE 12853A

69 MAD CK @ CHRISTINA SWA CDPHE 12863

81 NORTH FORK WALTON CREEK NR RABBIT EARS PASS, CO. USGS 09238300

83 OAK CK D/S TOWN OF OAK CREEK @ CR 27 CDPHE 12892

85 OAK CREEK AB OAK CREEK DRAIN NEAR OAK CREEK, CO. USGS 401725106575600

93 OAK CREEK NEAR OAK CREEK, CO. USGS 09238000

94 OAK CK @ 22 RD ABV YAMPA R CDPHE 12891

95 PHILLIPS CREEK NEAR YAMPA, CO. USGS 400759106532500

98 SAGE CK @ RD. 27 CDPHE 12851

188 Sage Creek in canyon on Rd 37 CDPHE 12851B

101 SAGE CREEK NEAR HAYDEN, CO. USGS 402918107094400

102 SAGE CREEK NEAR MOUNT HARRIS, CO. USGS 402522107134100

115 TROUT CK NR. MOUTH CDPHE 12876

116 TROUT CREEK ABOVE FOIDEL CREEK NEAR MILNER, CO. USGS 402416106580800

121 TROUT CREEK NEAR PHIPPSBURG, CO. USGS 09243000

122 WALTON CR. NEAR MOUTH @ HWY 40 CDPHE 12894

189 Wolf Creek at 52 Rd CDPHE 12855

128 WOLF CREEK NEAR HAYDEN, CO. USGS 402832107080200

133 YMP-7 [Yampa River 100m above James Brown Bridge] CSS1 YMP-7

136 YAMPA R. @ CR 14 FISHING ACCESS CDPHE 12806D

137 YAMPA R. ABV. PHIPPSBURG CDPHE 12814

138 YAMPA R. BLW STAGECOACH RES. CDPHE 12808

139 YAMPA R. D/S STAGECOACH RES. DAM CDPHE 12808P

140 YAMPA R. N. OF HAYDEN @ CALIFORNIA PARK RD CDPHE 12802

141 YAMPA R. NR MOUNT HARRIS BLW HWY 40 BRIDGE CDPHE 12805

142 YAMPA R. U/S LAKE CATAMOUNT @ CR18 CDPHE 12807
Appendix 6 127

Appendix 6. Description of stream sites in the Upper Yampa River watershed, Colorado, that have macroinvertebrate data, and period 

of water-quality record and number of sample days, 1975 through 2008.—Continued

[No., number; USGS, U.S. Geological Survey; CDPHE, Colorado Department of Public Health and Environment; CSS, City of Steamboat Springs. Subwatershed 

definitions: Yampa River subwatershed 1, Yampa River and tributaries upstream from Chuck Lewis State Wildlife Area; Yampa River subwatershed 2, Yampa River 

and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence; Elk River subwatershed, Elk River and tributaries; Yampa River subwatershed 3, Yampa 

River and tributaries from Elk River confluence to Town of Hayden; Yampa River subwatershed 4, Yampa River and tributaries from Town of Hayden to Elkhead Creek 

confluence; Elkhead Creek subwatershed, Elkhead Creek and tributaries. Sites with the same site number are considered to be at the same location]

Site no.

(see figure 18) Latitude Longitude Subwatershed Period of water-quality record(month/year)

No. of

sample days

6 40.044 –107.072 Yampa River subwatershed 1 8/1975 1

7 40.769 –106.916 Elk River subwatershed 9/1975 1

10 40.452 –106.810 Yampa River subwatershed 2 4/2001, 8/2001 2

180 40.201 –106.826 Yampa River subwatershed 2 9/2006 1

22 40.492 –107.265 Yampa River subwatershed 4 4/2003 1

27 40.546 –106.909 Elk River subwatershed 4/2001, 8/2001 2

30 40.717 –106.916 Elk River subwatershed 8/1975 1

33 40.515 –106.954 Elk River subwatershed 8/1975 1

38 40.660 –107.291 Elkhead Creek subwatershed 8/2000 1

39 40.620 –107.271 Elkhead Creek subwatershed 8/2001, 7/2008 2

40 40.592 –107.321 Elkhead Creek subwatershed 9/1975 1

181 40.755 –107.133 Elkhead Creek subwatershed 7/2008 1

182 40.676 –107.271 Elkhead Creek subwatershed 7/2008 1

183 40.592 –107.321 Elkhead Creek subwatershed 7/2008 1

184 40.669 –107.285 Elkhead Creek subwatershed 7/2008 1

185 40.539 –107.411 Elkhead Creek subwatershed 7/2008 1

43 40.531 –107.436 Elkhead Creek subwatershed 9/1975 1

43 40.531 –107.436 Elkhead Creek subwatershed 8/2001, 7/2008 2

44 40.670 –107.285 Elkhead Creek subwatershed 9/1975 1

186 40.731 –107.147 Elkhead Creek subwatershed 8/2005 1

54 40.467 –106.825 Yampa River subwatershed 2 4/2001, 8/2001 2

58 40.392 –107.139 Yampa River subwatershed 3 9/1975 1

59 40.447 –107.146 Yampa River subwatershed 3 9/1975 1

59 40.447 –107.146 Yampa River subwatershed 3 4/2003 1

187 40.390 –107.148 Yampa River subwatershed 3 4/2003 1

69 40.565 –106.889 Elk River subwatershed 10/1997, 9/1998, 7/2008 3

81 40.396 –106.650 Yampa River subwatershed 2 8/1975 1

83 40.276 –106.964 Yampa River subwatershed 1 4/2001, 8/2001 2

85 40.290 –106.966 Yampa River subwatershed 1 8/1975 1

93 40.244 –107.015 Yampa River subwatershed 1 8/1975 1

94 40.399 –106.842 Yampa River subwatershed 1 4/2001, 8/2001 2

95 40.133 –106.891 Yampa River subwatershed 1 8/1975 1

98 40.484 –107.170 Yampa River subwatershed 3 4/2003 1

188 40.404 –107.224 Yampa River subwatershed 3 7/2008 1

101 40.488 –107.163 Yampa River subwatershed 3 9/1975 1

102 40.423 –107.229 Yampa River subwatershed 3 9/1975 1

115 40.460 –106.989 Yampa River subwatershed 3 9/1998 1

116 40.404 –106.969 Yampa River subwatershed 3 8/1975 1

121 40.151 –107.132 Yampa River subwatershed 3 8/1975 1

122 40.270 –106.816 Yampa River subwatershed 2 4/2001, 8/2001 2

189 40.547 –107.113 Yampa River subwatershed 4 4/2003 1

128 40.476 –107.134 Yampa River subwatershed 4 9/1975 1

133 40.496 –106.857 Yampa River subwatershed 2 9/2005, 9/2007, 9/2008 23

136 40.475 –106.824 Yampa River subwatershed 1 4/2001, 8/2001 2

137 40.227 –106.941 Yampa River subwatershed 1 9/1998, 4/2001, 8/2001 3

138 40.287 –106.829 Yampa River subwatershed 1 8/1998 1

139 40.288 –106.827 Yampa River subwatershed 1 4/2001, 8/2001 2

140 40.502 –107.264 Yampa River subwatershed 3 4/2001, 8/2001 2

141 40.488 –107.158 Yampa River subwatershed 3 4/2001, 8/2001 2

142 40.341 –106.808 Yampa River subwatershed 1 4/2001, 8/2001 2
128 Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009

Appendix 6. Description of stream sites in the Upper Yampa River watershed, Colorado, that have macroinvertebrate data, and period 

of water-quality record and number of sample days, 1975 through 2008.—Continued

[No., number; USGS, U.S. Geological Survey; CDPHE, Colorado Department of Public Health and Environment; CSS, City of Steamboat Springs. Subwatershed 

definitions: Yampa River subwatershed 1, Yampa River and tributaries upstream from Chuck Lewis State Wildlife Area; Yampa River subwatershed 2, Yampa River 

and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence; Elk River subwatershed, Elk River and tributaries; Yampa River subwatershed 3, Yampa 

River and tributaries from Elk River confluence to Town of Hayden; Yampa River subwatershed 4, Yampa River and tributaries from Town of Hayden to Elkhead Creek 

confluence; Elkhead Creek subwatershed, Elkhead Creek and tributaries. Sites with the same site number are considered to be at the same location]

Site no.

(see figure 18) Site name Source of data Site identifier

143 YAMPA RIVER AB OAK CREEK NR STEAMBOAT SPGS, CO. USGS 402356106500000

143 YAMPA R. ABV OAK CREEK CDPHE 12811

145 YAMPA RIVER ABOVE ELK RIVER NEAR MILNER, CO. USGS 402932106564900

147 YAMPA R. U/S STAGECOACH RES @ CR16 CDPHE 12809

150 YAMPA RIVER AT HAYDEN, CO. USGS 403006107154800

151 YAMPA RIVER AT MILNER CDPHE 000038

152 YAMPA RIVER AT PHIPPSBURG, CO. USGS 401418106562200

153 YAMPA RIVER AT STEAMBOAT SPRINGS, CO USGS 09239500

153 YAMPA R. @ 5TH ST. BRIDGE IN STEAMBOAT CDPHE 12806

154 YAMPA RIVER BELOW DIVERSION, NEAR HAYDEN, CO. USGS 09244410

155 YAMPA RIVER BELOW HAYDEN, CO. USGS 402930107174200

162 YAMPA R. BLW YAMPA @ CR21 CDPHE 12815

169 YAMPA R. D/S LAKE CATAMOUNT @ HWY 131 CDPHE 12806F

174 YMP-1 [Yampa River 200m above confl Walton Creek] CSS1 YMP-1

175 YMP-2 [Yampa River 35m above confl Fish Creek] CSS1 YMP-2

176 YMP-3A [Yampa River 70m above pedestrian bridge and hot spring

outflow in Weiss Park]

CSS1 YMP-3A
Appendix 6 129

Appendix 6. Description of stream sites in the Upper Yampa River watershed, Colorado, that have macroinvertebrate data, and period 

of water-quality record and number of sample days, 1975 through 2008.—Continued

[No., number; USGS, U.S. Geological Survey; CDPHE, Colorado Department of Public Health and Environment; CSS, City of Steamboat Springs. Subwatershed 

definitions: Yampa River subwatershed 1, Yampa River and tributaries upstream from Chuck Lewis State Wildlife Area; Yampa River subwatershed 2, Yampa River 

and tributaries from Chuck Lewis State Wildlife Area to Elk River confluence; Elk River subwatershed, Elk River and tributaries; Yampa River subwatershed 3, Yampa 

River and tributaries from Elk River confluence to Town of Hayden; Yampa River subwatershed 4, Yampa River and tributaries from Town of Hayden to Elkhead Creek 

confluence; Elkhead Creek subwatershed, Elkhead Creek and tributaries. Sites with the same site number are considered to be at the same location]

Site no.

(see figure 18) Latitude Longitude Subwatershed Period of water-quality record(month/year)

No. of

sample days

143 40.399 –106.834 Yampa River subwatershed 1 8/1975 1

143 40.399 –106.834 Yampa River subwatershed 1 9/1998, 4/2001, 8/2001 3

145 40.492 –106.948 Yampa River subwatershed 2 8/1975 1

147 40.269 –106.881 Yampa River subwatershed 2 4/2001, 8/2001 2

150 40.502 –107.264 Yampa River subwatershed 3 9/1975 1

151 40.479 –107.013 Yampa River subwatershed 3 4/2001, 8/2001 2

152 40.238 –106.940 Yampa River subwatershed 1 8/1975 1

153 40.483 –106.832 Yampa River subwatershed 2 8/1975 1

153 40.483 –106.832 Yampa River subwatershed 2 9/1998, 4/2001 2

154 40.488 –107.160 Yampa River subwatershed 3 9/1975 1

155 40.492 –107.296 Yampa River subwatershed 3 9/1975 1

162 40.183 –106.915 Yampa River subwatershed 1 4/2001, 8/2001 2

169 40.375 –106.825 Yampa River subwatershed 1 4/2001, 8/2001 2

174 40.449 –106.820 Yampa River subwatershed 2 9/2005, 9/2007, 9/2008 2

3

175 40.466 –106.830 Yampa River subwatershed 2 9/2005, 9/2007, 9/2008 2

3

176 40.481 –106.828 Yampa River subwatershed 2 9/2005, 9/2007, 9/2008 2

3

1

Data collected by GEI Consultants, Inc.

2

Four samples were collected on the same day.

Publishing support provided by:

Denver Publishing Service Center, Denver, Colorado

For more information concerning this publication, contact:

Director, USGS Colorado Water Science Center

Box 25046, Mail Stop 415

Denver, CO 80225

(303) 236-4882

Or visit the Colorado Water Science Center Web site at:

http://co.water.usgs.gov/

This report is available at: http://pubs.usgs.gov/sir/2012/5214
Bauch and others—Water-Quality Assessment and Macroinvertebrate Data for the Upper Yampa River Watershed, Colorado, 1975–2009—SIR 2012–5214