Prepared in cooperation with the 

Colorado Department of Public Health and Environment 

Effect of Drought on Streamflow and 

Stream-Water Quality in Colorado, 

July through September 2002 

Scientific Investigations Report 2006–5322 

U.S. Department of the Interior 

U.S. Geological Survey 
Effect of Drought on Streamflow and 

Stream-Water Quality in Colorado,

July through September 2002

By Daniel T. Chafin and A. Douglas Druliner

Scientific Investigations Report 2006–5322

U.S. Department of the Interior

U.S. Geological Survey

Prepared in cooperation with the

Colorado Department of Public Health and Environment
U.S. Department of the Interior

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

Mark D. Myers, Director

U.S. Geological Survey, Reston, Virginia: 2007

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Suggested citation:

Chafin, D.T., and Druliner, A.D., 2007, Effect of drought on streamflow and stream-water quality in Colorado, July 

through September 2002: U.S. Geological Survey Scientific Investigations Report 2006–5322, 134 p.
iii

Contents

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

Introduction.....................................................................................................................................................1

Purpose and Scope .............................................................................................................................2

Methods .................................................................................................................................................2

Ranking by Percentiles ..............................................................................................................2

 Colorado Water-Quality-Standard Exceedances .................................................................8

Effect of Drought on Streamflow ................................................................................................................8

Effect of Drought on Water Quality.............................................................................................................8

Yampa and White River Basins .........................................................................................................8

Upper Colorado River Basin .............................................................................................................11

Rio Grande Basin ...............................................................................................................................13

Gunnison River Basin ........................................................................................................................13

Dolores River Basin ...........................................................................................................................16

San Juan River Basin ........................................................................................................................17

South Platte River Basin ...................................................................................................................18

Arkansas River Basin ........................................................................................................................21

Statewide Overview ...........................................................................................................................24

Summary........................................................................................................................................................26

References Cited..........................................................................................................................................28

Appendix........................................................................................................................................................29

Figures

1–7. Maps showing:

 1. River basins in Colorado sampled for this study.....................................................2

 2. Percentiles of mean annual flow in Colorado for water year 2002

 relative to mean annual flow during 1978–2002......................................................9

 3. Percentiles of mean summer (July–September) flow in Colorado

 for 2002 relative to mean summer flow during 1978–2002 ..................................10

 4. Sampling sites in the Yampa, White, and Upper Colorado River Basins ..........12

 5. Sampling sites in the Rio Grande, Gunnison, Dolores, and San Juan

 River Basins................................................................................................................15

 6. Sampling sites in the South Platte River Basin.....................................................19

 7. Sampling sites in the Arkansas River Basin..........................................................22
iv

Tables

1. Colorado stream sites where water-quality samples were collected

during July through September 2002.........................................................................................3

2. Average percentiles and results for summer 2002 drought water-quality

data from sites in the Yampa and White River Basins, relative to historical

data from July through September, 1978–2002......................................................................11

3. Average percentiles and results for summer 2002 drought water-quality

data from sites in the Upper Colorado River Basin, relative to historical

data from July through September, 1978–2002......................................................................14

4. Average percentiles and results for summer 2002 drought water-quality

data from sites in the Rio Grande Basin, relative to historical data from

July through September, 1978–2002. .......................................................................................16

5. Average percentiles and results for summer 2002 drought water-quality

data from sites in the Gunnison River Basin relative to historical data

from July through September, 1978–2002...............................................................................17

6. Average percentiles and results for summer 2002 drought water-quality

data from sites in the Dolores River Basin relative to historical data from

July through September, 1978–2002. .......................................................................................18

7. Average percentiles and results for summer 2002 drought water-quality

data from sites in the San Juan River Basin, relative to historical data

from July through September, 1978–2002...............................................................................18

8. Average percentiles and results for summer 2002 drought water-quality

data from sites in the South Platte River Basin relative to historical data

from July through September, 1978–2002...............................................................................20

9. Average percentiles and results for summer 2002 drought water-quality

data from sites in the Arkansas River Basin relative to historical data

from July through September, 1978–2002...............................................................................23

10. Summary of characterization of percentiles for properties and constituents

in drought samples collected from sites in Colorado during summer 2002

compared to 1978–2002. ............................................................................................................25

11. Water-quality data for the Yampa and White River Basins, showing

2002 drought values, Colorado water-quality exceedances, and percentiles

relative to historical data for selected properties and constituents from July

through September, 1978–2002.................................................................................................30

12. Water-quality data for the Upper Colorado River Basin, showing 2002

 drought values, Colorado water-quality exceedances, and percentiles

relative to historical data for selected properties and constituents from

July through September, 1978–2002. .......................................................................................40

13. Water-quality data for the Rio Grande Basin showing 2002 drought values,

Colorado water-quality exceedances, and percentiles relative to historical

data for selected properties and constituents from July through September,

1978–2002. ....................................................................................................................................84

14. Water-quality data for the Gunnison River Basin showing 2002 drought

values, Colorado water-quality exceedances, and percentiles relative

to historical data for selected properties and constituents from July through

September, 1978–2002................................................................................................................88
v

Multiply By To obtain

Volume

liter (L) 0.2642 gallon (gal)

Mass

gram (g) 0.03527 ounce, avoirdupois (oz)

Streamflow

cubic meters per second (m3/s) 35.31 cubic feet per second (ft3/s)

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 1927 (NAD 27).

Abbreviations or Terms

as N as quantified, as measured nitrogen

as P as quantified, as measured phosphorus

col/100 mL colonies per 100 milliliters

μg/L micrograms per liter

μS/cm microsiemens per centimeter at 25 degrees Celsius

mg/L milligrams per liter

Q% percentile

SU standard units (pH)

Conversion Factors and Datums

15. Water-quality data for the Dolores River Basin showing 2002 drought

values, Colorado water-quality exceedances, and percentiles relative

to historical data for selected properties and constituents from July

through September, 1978–2002.................................................................................................95

16. Water-quality data for the San Juan River Basin showing 2002 drought

values, Colorado water-quality exceedances, and percentiles relative

to historical data for selected properties and constituents from July

through September, 1978–2002.................................................................................................98

17. Water-quality data for the South Platte River Basin showing 2002 drought

values, Colorado water-quality exceedances, and percentiles relative to

historical data for selected properties and constituents from July through

September, 1978–2002..............................................................................................................104

18. Water-Quality data for the Arkansas River Basin showing 2002 drought

values, Colorado water-quality exceedances, and percentiles relative to

historical data for selected properties and constituents from July through

September, 1978–2002..............................................................................................................118

Abstract

During 2002, Colorado experienced the State’s worst 

drought since 1977. In 2003, the U.S. Geological Survey 

entered into cooperative agreement with the Colorado Department of Public Health and Environment to evaluate the general 

effects of drought on the water quality of streams in Colorado 

during summer 2002 by analyzing a water-quality data set 

obtained during summer 2002 in cooperation with a variety of 

State and local governments. Water samples were collected at 

148 stream sites in Colorado and were measured or analyzed 

for field properties, major ions, nutrients, organic carbon, bacteria, and dissolved and total recoverable metals.

Mean annual streamflow was analyzed at 134 sites in 

Colorado, and mean summer (July–September) streamflow for 

2002 was determined for 146 sites for water years 1978–2002. 

Mean annual streamflow for 2002 had an average percentile 

of 29.4 and mean summer streamflow for 2002 had an average percentile of 7.6 relative to 1978–2002. These results 

indicate that streamflow in Colorado was substantially less 

than median streamflow for the period and that the effect of 

drought on streamflow was greater during summer 2002 than 

during water year 2002 (October 1, 2001, through September 30, 2002).

Few measured constituent concentrations or values were 

elevated or depressed on a widespread basis during summer 

2002. Specific conductance was elevated (in the upper quartile 

relative to historical data) in five of the seven basins that had 

sufficient data for characterization, indicating that specific 

conductance likely was affected by drought in those basins. 

Chloride concentrations were elevated in three of five basins 

with sufficient data and indicate that chloride concentration 

generally was affected by drought in those basins. Sulfate 

concentration was elevated in four of six basins with sufficient 

data. The widespread elevation of specific conductance and 

concentrations of chloride and sulfate indicates that salinity 

generally was affected by drought in Colorado streams during 

July–September 2002, likely because streamflow at most sites 

was dominated by base flow of ground water, which usually 

has substantially greater salinity compared to runoff from precipitation. Total-recoverable iron and manganese concentrations were depressed (in the lower quartile of historical data) 

in the Arkansas River Basin, which likely was due to reduced 

land-surface washoff of sediment containing oxyhydroxides of 

these metals.

Of the 246 water samples collected at 148 sites during 

the summer of 2002, constituents in 115 exceeded Colorado 

water-quality standards. Constituents that exceeded waterquality standards were pH (all 9.0 standard unit exceedances; 

9 samples), chloride (1 sample), sulfate (9 samples), dissolved 

ammonia (10 samples), dissolved nitrite nitrogen (3 samples), 

E. coli (Escherichia coli) bacteria (34 samples, 20 in Arkansas River Basin), fecal-coliform bacteria (18 samples, all in 

Arkansas River Basin), dissolved copper (1 sample), dissolved 

iron (3 samples), total-recoverable iron (3 samples), dissolved 

manganese (13 samples), dissolved selenium (10 samples), 

and dissolved zinc (1 sample). Of these 115 exceedances, 

historical data were sufficient to conclude that 21 probably 

were affected by drought, that 39 probably were not affected 

by drought, and that 55 were of indeterminate nature. 

Specific conductance indicates that the San Juan River 

Basin (average percentile 95.2) experienced the greatest 

effects of drought on water quality during summer 2002 

compared to other basins in Colorado, followed by the Upper 

Colorado (90.0) and Dolores River (85.7) Basins. The South 

Platte River Basin (70.9) experienced the least effect of 

drought, and the Yampa and White River Basin group (73.7) 

had the second smallest effect. The Gunnison River (82.1) and 

Arkansas River (81.2) Basins had intermediate drought effects. 

The Rio Grande had insufficient data to rank the relative effect 

of drought on salinity.

Introduction

During 2002, Colorado experienced the State’s worst 

drought since 1977 (Kuhn, 2005). To determine the effects 

of the 2002 drought on streamflow and stream-water quality 

in the State during the summer months, a variety of State and 

local governments cooperated with the U.S. Geological Survey 

(USGS) to collect water-quality samples at 148 stream sites 

in the nine major river basins in Colorado (fig. 1). In 2003, 

the U.S. Geological Survey, in cooperation with the Colorado Department of Public Health and Environment, began 

Effect of Drought on Streamflow and Stream-Water 

Quality in Colorado, July through September 2002

By Daniel T. Chafin and A. Douglas Druliner
to examine these data. Water samples were analyzed for field 

properties, major ions, nutrients, organic carbon, bacteria, and 

dissolved metals at all sites, although individual constituents in 

these categories varied among basins. Results of the analyses 

were reported in Crowfoot, Payne, and O’Neill (2003) and in 

Crowfoot, Boulger, and O’Neill (2003). 

Purpose and Scope 

This report presents water-quality data collected at 

148 sites on rivers and creeks in Colorado during drought 

conditions for the period July–September 2002. The report 

summarizes water-quality data for 2002 relative to data from 

1978 through 2001 and percentiles of constituent concentrations during summer 2002 relative to historical data for each 

site for the months of July through September during 1978 

through 2001. In addition, the report presents exceedances 

of Colorado water-quality standards for constituents sampled 

during summer 2002. 

Methods 

Between July 11, 2002, and September 30, 2002, 

148 stream sites (table 1) were sampled by the equal-widthincrement method (U.S. Geological Survey, 1998) to obtain 

representative water-quality samples. Water samples were collected twice at 98 of these sites for a total of 246 samples. 

Water samples collected at these sites are hereinafter 

referred to as “drought samples.” Individual drought samples 

were measured for field properties (dissolved oxygen, pH, 

specific conductance, and water temperature) and collected 

for laboratory analysis and were processed, preserved, and 

shipped according to standard guidelines (U.S. Geological Survey, 1998). All samples were shipped to the USGS 

National Water-Quality Laboratory in Lakewood, Colorado, for laboratory analyses. Data are reported by basin in 

tables 11–18 in the Appendix at the back of this report. 

Ranking by Percentiles 

The primary tool used to evaluate concentrations of 

constituents in water-quality samples collected during summer 2002 was ranking by percentile. Percentiles were 

calculated for each water-quality constituent for each site 

sampled during the 2002 drought by using the population of 

all samples for each site from July through September for 

1978 through 2002 that had 20 or more samples (including 

the samples collected during the drought). Percentiles calculated for fewer than 20 samples were not considered to be 

statistically reliable. Percentiles were calculated only for the 

months of July–September to maintain a common basis for 

comparison among years so that the effects of drought during 

July–September 2002 could be assessed. Data collected prior 

to 1978 were not included, primarily to preclude comparison 

0

0 50 100 KILOMETERS

50 100 MILES

ARKANSAS

RIVER BASIN

SOUTH PLATTE

RIVER BASIN

YAMPA

RIVER BASIN

WHITE

RIVER BASIN

SAN JUAN

RIVER BASIN

UPPER COLORADO

RIVER BASIN

GUNNISON

RIVER BASIN

DOLORES

RIVER

BASIN

RIO GRANDE

BASIN

Figure 1. River basins in Colorado sampled for this study.

   Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
Site

number in

figures 4–7

U.S. Geological

Survey

station number

U.S. Geological Survey station name

Yampa River Basin (figure 4)

1 09238900 Fish Creek at upper station near Steamboat Springs

2 09239500 Yampa River at Steamboat Springs

3 09242500 Elk River near Milner

4 09246400 Elkhead Creek below Maynard Gulch near Craig

5 09247600 Yampa River below Craig

6 09249750 Williams Fork at mouth

7 09251000 Yampa River near Maybell

8 09260050 Yampa River at Deerlodge Park

White River Basin (figure 4)

9 09303000 North Fork White River at Buford

10 09304000 South Fork White River at Buford

11 09304200 White River above Coal Creek near Meeker

12 09304800 White River below Meeker

13 09306200 Piceance Creek below Ryan Gulch near Rio Blanco

14 09306222 Piceance Creek at White River

15 09306242 Corral Gulch near Rangely

16 09306255 Yellow Creek near White

17 09306290 White River below Boise Creek near Rangely

18 09306305 White River below Taylor Draw Reservoir near Rangely

19 395650107435600 White River above Dry Creek

Upper Colorado River Basin (figure 4)

20 09019000 Colorado River below Lake Granby

21 09022000 Fraser River at upper station near Winter Park

22 09023750 Fraser River below Buck Creek at Winter Park

23 09025010 Fraser River below Vasquez Creek at Winter Park

24 09027100 Fraser River at Tabernash

25 09033100 Ranch Creek below Meadow Creek near Tabernash

26 09033300 Fraser River below Crooked Creek at Tabernash

27 09034250 Colorado River at Windy Gap near Granby

28 09038500 Williams Fork below Williams Fork Reservoir

29 09040500 Troublesome Creek near Troublesome

30 09041090 Muddy Creek above Antelope Creek near Kremmling

31 09041400 Muddy Creek below Wolford Mountain Reservoir near Kremmling

32 09057700 Blue River at mouth near Kremmling

33 09058000 Colorado River near Kremmling

34 09063000 Eagle River at Red Cliff

35 09066510 Gore Creek at mouth near Minturn

36 09067005 Eagle River at Avon

37 09069000 Eagle River at Gypsum

Table 1. Colorado stream sites where water-quality samples were collected during July through September 2002.

Introduction 
Site

number in

figures 4–7

U.S. Geological

Survey

station number

U.S. Geological Survey station name

Upper Colorado River Basin (figure 4)—Continued

38 09070500 Colorado River near Dotsero

39 09071750 Colorado River above Glenwood Springs

40 09073300 Roaring Fork River above Difficult Creek near Aspen

41 09081000 Roaring Fork River near Emma

42 09081600 Crystal River above Avalanche Creek near Redstone

43 09083800 Crystal River below Carbondale

44 09085000 Roaring Fork River at Glenwood Springs

45 09087600 Colorado River at New Castle

46 09095300 Dry Fork at upper station near De Beque

47 09095500 Colorado River near Cameo

48 09105000 Plateau Creek near Cameo

49 09106150 Colorado River below Grand Valley diversion near Palisade

50 09106500 Colorado River at Grand Junction

51 09153000 Colorado River near Fruita

52 09163500 Colorado River near Colorado-Utah state line

53 390318108273200 Colorado River at 32 Road near Clifton

54 390521108373300 Colorado River at Redlands Parkway near Grand Junction

55 392511106164000 East Fork Eagle River near Red Cliff

56 393143107465200 Colorado River near Rifle

57 394220106431500 Eagle River below Milk Creek near Wolcott

58 400453105554200 Fraser River at Highway 40 at Granby

Rio Grande Basin (figure 5)

59 08220000 Rio Grande near Del Norte

60 08246500 Conejos River near Mogote

61 08251500 Rio Grande near Lobatos

62 374900106545100 Rio Grande above Deep Creek near Creede

Gunnison River Basin (figure 5)

63 09112200 East River below Cement Creek near Crested Butte

64 09112500 East River at Almont

65 09113980 Ohio Creek above mouth near Gunnison

66 09114500 Gunnison River near Gunnison

67 09119000 Tomichi Creek at Gunnison

68 09128000 Gunnison River below Gunnison Tunnel

69 09135950 North Fork of Gunnison River below Leroux Creek near Hotchkiss

70 09144250 Gunnison River at Delta

71 09146020 Uncompahgre River near Ouray

72 09146200 Uncompahgre River near Ridgway

73 09149500 Uncompahgre River at Delta

74 09152500 Gunnison River near Grand Junction

Table 1. Colorado stream sites where water-quality samples were collected during July through September 2002.­—Continued

   Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
Site

number in

figures 4–7

U.S. Geological

Survey

station number

U.S. Geological Survey station name

Gunnison River Basin (figure 5)—Continued

75 383103106594200 Gunnison River at County Road 32 below Gunnison

76 383126106475600 Tomichi Creek below Chetopa Creek near Parlin

77 383604106312400 Quartz Creek below Pitkin

78 384624107570701 Gunnison River at 2200 Road bridge at Austin

79 384950106544200 East River above Slate River near Crested Butte

80 385224106590100 Coal Creek above mouth at Crested Butte

81 385240106583600 Slate River above Coal Creek near Crested Butte

82 385325106581200 Washington Gulch below Woods Creek at Mount Crested Butte

83 385408106543600 East River above Crested Butte

Dolores River Basin (figure 5)

84 09166500 Dolores River at Dolores

85 09169500 Dolores River at Bedrock

86 09171100 Dolores River near Bedrock

87 09172500 San Miguel River near Placerville

88 09177000 San Miguel River at Uravan

San Juan River Basin (figure 5)

89 09349800 Piedra River near Arboles

90 09352900 Vallecito Creek near Bayfield

91 09354500 Los Pinos River at La Boca

92 09359020 Animas River below Silverton

93 09361500 Animas River at Durango

94 09363200 Florida River at mouth at Bondad

95 09366500 La Plata River at Colorado-New Mexico state line

96 09370000 Mancos River near Mancos

97 09371492 Mud Creek at State Highway 32 near Cortez

98 09371520 McElmo Creek above Trail Canyon near Cortez

99 09372000 McElmo Creek near Colorado-Utah state line

100 370907107530401 Animas River at Weaselskin Bridge near La Posta

101 371319107515001 Animas River near Carbon Junction

102 371500107004601 San Juan River below Pagosa Springs

South Platte River Basin (figure 6)

103 06713500 Cherry Creek at Denver

104 06714000 South Platte River at Denver

105 06719505 Clear Creek at Golden

106 06720500 South Platte River at Henderson

107 06733000 Big Thompson River at Estes Park

108 06734900 Olympus tunnel at Lake Estes

109 06735500 Big Thompson River near Estes Park

110 06736000 North Fork Big Thompson River at Drake

Table 1. Colorado stream sites where water-quality samples were collected during July through September 2002.­—Continued

Introduction   
Site

number in

figures 4–7

U.S. Geological

Survey

station number

U.S. Geological Survey station name

South Platte River Basin (figure 6)—Continued

111 06741510 Big Thompson River at Loveland

112 06741530 Big Thompson River at Interstate 25 near Loveland

113 06752260 Cache la Poudre River at Fort Collins

114 06752280 Cache la Poudre River above Boxelder Canyon near Timnath

115 06753990 Lonetree Creek near Greeley

116 06754000 South Platte River near Kersey

117 06758500 South Platte River near Weldona

118 06764000 South Platte River at Julesburg

119 09013000 Alva B. Adams Tunnel at East Portal near Estes Park

120 393948105053501 Bear Creek below Estes Road at Lakewood

121 402114105350101 Big Thompson River below Moraine Park near Estes Park

122 402533105124300 Big Thompson River below Sulzer Gulch near Loveland

123 402535105105700 Buckhorn Creek at County Road 24 near Loveland

124 402554105202100 Big Thompson River above North Fork of Big Thompson at Drake

125 403048105042701 Fossil Creek at College Avenue at Fort Collins

Arkansas River Basin (figure 7)

126 07086000 Arkansas River at Granite

127 07096000 Arkansas River at Canon City

128 07097000 Arkansas River at Portland

129 07099200 Arkansas River near Portland

130 07099400 Arkansas River above Pueblo

131 07099970 Arkansas River at Moffat Street at Pueblo

132 07103700 Fountain Creek near Colorado Springs

133 07103780 Monument Creek above North Gate Boulevard at U.S. Air Force Academy

134 07103970 Monument Creek above Woodmen Road at Colorado Springs

135 07104905 Monument Creek at Bijou Street at Colorado Springs

136 07105500 Fountain Creek at Colorado Springs

137 07105530 Fountain Creek below Janitell Road below Colorado Springs

138 07105800 Fountain Creek at Security

139 07106000 Fountain Creek near Fountain

140 07106300 Fountain Creek near Pinon

141 07109500 Arkansas River near Avondale

142 07119700 Arkansas River at Catlin Dam near Fowler

143 07120500 Arkansas River near Rocky Ford

144 07123000 Arkansas River at La Junta

145 07124000 Arkansas River at Las Animas

146 07124200 Purgatoire River at Madrid

147 07126500 Purgatoire River at Ninemile Dam near Higbee

148 07133000 Arkansas River at Lamar

Table 1. Colorado stream sites where water-quality samples were collected during July through September 2002.­—Continued

   Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
with data that were collected during earlier droughts, including the last one, which ended in 1977. This restriction also 

minimized comparison of 2002 data with data that were collected before construction of major reservoirs in the 1960s and 

1970s. For major ions, percentiles were calculated only for 

chloride and sulfate because they are the only major ions for 

which Colorado water-quality standards have been established. 

Percentiles also were calculated for mean annual and mean 

summer streamflow during 2002 relative to 1978–2002 to 

evaluate the effect of drought on streamflow.

The percentile for a specific observation in a data set is 

defined as the percentage of the number of observations in 

the data set that have values less than or equal to that of the 

specific observation (Helsel and Hirsch, 1992). For example, if 

a pH value of 7.4 in a data set is ranked at the 30th percentile, 

then about 30 percent of the ranked pH values are less than 

or equal to 7.4. Percentiles were calculated using the Weibull 

formula as described by (Helsel and Hirsch, 1992):

Q% = 100 × R/(N+1) (1) 

where

Q% is the value of the percentile for a given 

observation,

R is the whole-number, high rank of the 

observation (ascending order),

and

N is the number of observations in the ranked 

data set

Calculation of percentiles for censored data sets—those 

having some observations reported as “less than” (<) a 

threshold concentration—required recensoring to a common 

basis when the threshold concentration varied among censored 

observations or when uncensored concentrations were less 

than one or more censored concentrations. Recensoring was 

required because of the inability to distinguish ranks given the 

varying thresholds for censored data. For example, dissolved 

cadmium concentrations of <0.1, <1, and <50 μg/L (micrograms per liter) cannot be distinguished by rank because 

the actual concentrations reported as <1 μg/L and <50 μg/L 

might be smaller than the actual concentration reported as 

<0.1 μg/L. Therefore, the smaller two of these concentrations would require recensoring to <50 μg/L, as would any 

uncensored concentration less than 50 μg/L (Helsel, 1990). In 

this example, if only one or two observations were reported 

as <50 μg/L, the drought sample was censored at a smaller 

threshold concentration, and the <50 μg/L observations was 

discarded from the data set (assuming at least 20 observations 

remained) to allow better resolution of the percentile for the 

drought sample; then recensoring would be done to the largest censored concentration that remained. Recensoring was 

not necessary when the drought sample had a concentration 

that exceeded the largest censored concentration or when the 

censored drought sample was unambiguously the smallest 

concentration. 

Assigning ranks to censored or tied values involves 

some ambiguity. This ambiguity is illustrated in the following 

generic example with eight observations, which shows how 

“low ranks” and “high ranks” may be assigned to such values. 

The low and high ranks bound the possible range of ranks that 

might be associated with censored values: 

Value High rank Low rank

<1 3 1

<1 3 1

<1 3 1

1 4 4

2 5 5

3 7 6

3 7 6

4 8 8

Using high ranking as previously described, ties (censored, recensored, or uncensored) in some data sets resulted 

in drought-sample percentiles that assumed the maximum 

possible rank for the tied data. For example, if a hypothetical drought sample and 94 historical samples for a site had a 

dissolved-iron concentration of <10 μg/L and only 4 historical 

samples exceeded this concentration, the resulting droughtsample percentile of 95 percent would spuriously indicate an 

elevated drought-sample concentration when, as far as the 

data can indicate, the true drought-sample concentration could 

fall anywhere in the lowest 95 percent of the data. Similarly, 

in some cases, ties of uncensored observations spuriously 

indicate elevated drought-sample values or concentrations. 

For example, if a drought sample and 10 historical samples 

for a site had a pH of 8.1, 82 historical samples had lower pH, 

and 6 historical samples had higher pH, then the calculated 

drought-sample percentile would be 93 percent when, in fact, 

the true drought-sample pH (which hypothetically could be 

indicated by values reported with greater precision) might rank 

anywhere between a percentile of 83 and 93 percent (inclusive). In cases where tied ranks caused uncertainty in calculated percentiles, the possible percentile range was calculated 

by using both low and high ranks, and the possible percentile 

range was reported and flagged by footnotes indicating the 

type of ties in tables 11–18 (at the back of this report).

To determine the effect of drought on the water quality of individual basins, a mean percentile was calculated for 

each constituent with a calculated percentile for all sites in 

the basin. For sites with more than one drought sample, only 

the most recent sample was used to compute the average 

percentile for that constituent for that basin. Also, the mean 

percentile was used in place of percentile ranges for individual 

samples when calculating basin constituent percentiles. The 

constituent was concluded to be “elevated” in concentration or 

value when the mean percentile was equal to or greater than 75 

(that is, was in the upper quartile of the data). The

Introduction   
constituent was concluded to be “depressed” when the mean 

percentile was less than 25 (that is, was in the lower quartile 

of the data). The constituent was considered to be “medial” 

when the mean percentile was between 25 and 74.9 (that is, 

was in the interquartile range of the data). Basins with fewer 

than three sites with calculated constituent percentiles were 

not rated. In cases where tied observations caused a range in 

possible percentile for one or more sites, the mean (midpoint) 

of the range(s) was used to calculate mean percentile for the 

basin. In cases where the conclusion of average effect was 

an “elevated” or “depressed” value or concentration and the 

uncertainty associated with the percentile range(s) indiciated the possibility of another conclusion, the conclusion was 

designated as “tentative” and identified as such in tables 2–9 

in the “Effect of Drought on Water Quality” section and in 

table 10 in the “Statewide Overview” section.

 Colorado Water-Quality-Standard Exceedances 

Water-quality data collected during July through September 2002 were compared to regulatory standards promulgated 

by the State of Colorado (Colorado Department of Public 

Health and Environment, 2005) to determine which constituents had concentrations or values that exceeded regulatory 

standards. Because prolonged exceedances are required before 

there is a legal violation of the water-quality standard, the 

designation of exceedances in this report are not be considered 

as actual legal violations of water-quality standards.

Most dissolved-metal concentrations in samples were 

compared to standards based on water hardness (a function 

of dissolved calcium and magnesium concentrations). The 

standard for un-ionized ammonia was applied by calculating 

the fraction of un-ionized ammonia in each sample, using total 

dissolved-ammonia concentration, water temperature, and 

pH. Water-quality exceedances for drought samples at each 

site were compared to historical exceedances for each site 

for July–September 1978 through 2001 to determine whether 

the drought-sample exceedances might have been affected by 

drought. Exceedances for samples collected during the drought 

are assumed to be affected by the drought: (1) if there is a total 

of 6 or more historical samples at the same site as the drought 

sample, all of which show no exceedances and the maximum 

historical value is one-half or less of the value of the lowest 

drought exceedance; or (2) if there are 10 or more historical 

samples at the same site with no more than 10 percent exceeding the standard.

Effect of Drought on Streamflow 

To determine the effect of the 2002 drought on streamflow in Colorado for the 25-water-year period 1978 through 

2002, percentiles were calculated for mean annual streamflow 

and mean summer (defined as July 1 through September 30) 

streamflow, using equation 1. (Mean annual streamflow is 

based on water year, which begins on October 1 and ends on 

September 30 of the following year.) 

Mean annual streamflow was analyzed at 134 sites in 

Colorado for years 1978–2002 (fig. 2). Forty-one of these 

sites also were sampled during the 2002 drought. Mean annual 

streamflow for 2002 had an average percentile of 29.4 percent 

during this period, indicating that overall streamflow in Colorado was substantially less than median percentile streamflow 

for the period. Twenty sites (15 percent) had the smallest mean 

annual streamflow during 2002, and only 16 sites (12 percent) 

had percentiles for 2002 that exceeded median streamflow 

during 1978–2002. These data indicate substantial drought 

conditions during water year 2002.

Mean summer (July–September) streamflow for 2002 

(fig. 3) was determined for 146 sites in Colorado, and percentiles averaged 7.6 percent when compared to summer streamflow for 1978–2002 for 134 sites across Colorado. Fifty-two 

of these sites were sampled during the 2002 drought. During 

2002, 116 sites (79 percent) had the smallest mean summer streamflow for 1978–2002, and only 3 sites (2 percent) 

had percentiles for 2002 that exceeded median streamflow 

for the period. Furthermore, because mean summer streamflow for 2002 had a substantially smaller average percentile 

(7.6 percent) than did mean annual streamflow for 2002 

(29.4 percent), one can conclude that the effect of drought on 

streamflow was greater during summer 2002 than during water 

year 2002.

Effect of Drought on Water Quality

Results of water-quality sampling during 2002, calculated percentiles (Q%), number (N) of 1978–2002 samples 

(including only drought samples for 2002), and Colorado 

water-quality exceedances are shown by river basin in tables 

11–18 in the Appendix at the back of this report. Percentiles 

are not reported for major ions except chloride and sulfate 

or for any property or constituent that did not have at least 

20 samples at a site. Columns showing percentile and number 

of samples were omitted for properties or constituents with no 

reported percentile in each table. The following sections discuss results for the following river basins (fig. 1): (1) Yampa 

and White (combined); (2) Upper Colorado; (3) Rio Grande; 

(4) Gunnison; (5) Dolores; (6) San Juan; (7) South Platte; and 

(8) Arkansas. Finally, a statewide overview section discusses 

general results for all of these basins, including properties or 

constituents for which results were too infrequent for discussion by basin.

Yampa and White River Basins 

Drought samples were collected at 8 sites in the Yampa 

River Basin and at 11 sites in the White River Basin (table 11, 

fig. 4). Because both basins are adjacent, independent tributaries of the Green River, samples collected in these basins 

 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
Base from U.S. Geological Survey digital data

1:100,000 Lambert Conformal Conic projectionStandard parallels 33oN and 45oNCentral meridian 105o30'W

EXPLANATION

Percentiles of surface-water statio

3.8 to 7.711.5 to 23.126.9 to 38.542.3 to 49.950.0 to 84.6

Fountain FourmileCr

River

Cr

Creek

Horse

Rush

Big

Creek Creek Sandy

Black Squirrel

Creek

Purgatoire

River

River

River

St

R

Apishapa

Huerfano Charles

Chalk Cr

John Martin Reservoir

0

0 50 100 KILOMETERS

50 100 MILES

Cache Poudre

River

South Platte

River

La

St Vrain

Thompson R Big Cr

Cr

Box Creek Creek Elder Cr Creek

Kiowa Beaver

Bijou

Cr Clear

CherryCr

South

Platte

River

Boulder

Little

Yampa

Williams

River River

Blue

Eagle

Fork

River

River

RoaringFork Colorado River

Piceance

Roan

Cr

Cr

White

Elkhead Elk

SnakeR CrRiver

Dillon

Res

Blue

Mesa

Res

Leadville

Salida

Cañon City

Fountain

Pueblo

Walsenburg

Trinidad

La Junta

Lamar

Limon

Las Animas

Kit Carson

Colorado

Springs

Julesbu

Fort Morgan

Fort Collins

Estes Park Greeley

Boulder

Golden Denver

Castle Rock

Craig

Meeker

Rifle

Glenwood Springs

Grand Junction

Dinosaur

Granby

Dillon

Steamboat Springs

Delta

Montrose

Telluride Creede

Pagosa

Springs

SilvertonDurango Cortez

Gunnison

Saguache

Alamosa

Gunnison

San

River

R

Animas

River

Mc Elmo

Mancos

Miguel

Dolores

Tomichi

Rio

Grande

Saguache

Taylor

Conejos River

R

R

Cr

Cr Cr

R

Los San Juan Piedra

River

Pinos

R

R

Disappointment

Cr

Figure 2. Percentiles of mean annual flow in Colorado for water year 2002 relative to mean annual flow during 1978–200
Base from U.S. Geological Survey digital data

1:100,000 Lambert Conformal Conic projectionStandard parallels 33oN and 45oNCentral meridian 105o30'W

EXPLANATION

Percentiles of surface-water stations

3.8 to 7.711.5 to 23.126.9 to 38.542.3 to 49.950.0 to 76.9

Fountain

FourmileCr

River

Cr

Creek Horse

Rush

Big

Creek

Creek

Sandy

Black Squirrel Creek

Purgatoire

River

River

River

St

R

Apishapa

Huerfano

Charles

Chalk Cr

John Martin Reservoir

0

0 50 100 KILOMETERS

50 100 MILES

Cache

Poudre River

South

Platte

River

La

St

Vrain

Thompson

R

Big

Cr

Cr

Box

Creek

Creek

 Elder Cr

Creek

Kiowa

Beaver

Bijou

Cr Clear

CherryCr

South Platte River

Boulder

Little

Yampa

Williams

River

River

Blue

Eagle

Fork

River

River

RoaringFork

Colorado

River

Piceance

Roan

Cr

Cr

White

Elkhead

Elk

SnakeR

Cr

River

Dillon

Res

Blue

Mesa

Res

Leadville

Salida

Cañon City

Fountain

Pueblo

Walsenburg

Trinidad

La Junta

Lamar

Limon

Las Animas

Kit Carson

Colorado

Springs

Julesburg

Fort Morgan

Fort Collins

Estes Park Greeley

Boulder

Golden Denver

Castle Rock

Craig

Meeker

Rifle

Glenwood Springs

Grand Junction

Dinosaur

Granby

Dillon

Steamboat Springs

Delta

Montrose

Telluride Creede

Pagosa

Springs

SilvertonDurango Cortez

Gunnison

Saguache

Alamosa

Gunnison

San

River

R

Animas

River

Mc Elmo

Mancos

Miguel

Dolores

Tomichi

Rio

Grande

Saguache

Taylor

Conejos

River

R

R

Cr

Cr Cr

R

Los

San Juan

Piedra

River

Pinos R

R

Disappointment

Cr

Figure 3. Percentiles of mean summer (July–September) flow in Colorado for 2002 relative to mean summer flow during 197
were jointly interpreted. Average percentile for properties 

and constituents (table 2) indicate medial values or concentrations for all properties or constituents with sufficient 

data—including field properties, dissolved major and minor 

constituents (chloride, fluoride, silica, and sulfate), most dissolved and total-recoverable nutrients, and dissolved boron 

and iron. Thus, it appears that drought conditions did not have 

a substantial influence on concentrations of these constituents. 

Dissolved organic carbon and dissolved metals (manganese, 

selenium, and zinc) had fewer than three useful percentiles and 

could not be characterized. Total-recoverable metals were not 

sampled in these two basins.

Only two drought samples exceeded Colorado waterquality standards (table 11). On July 29, 2002, the pH at site 2 

was 9.3 SU, exceeding the upper standard for aquatic life, 

recreational use, and domestic water supply of 9.0 standard 

units. Eleven historical samples had a maximum pH of 8.9. 

Because of the potential diurnal fluctuation of pH at these sites 

and variable measurement time (Chafin, 2002), it is uncertain 

if this exceedance was affected by drought. On September 4, 

2002, the dissolved manganese concentration at site 8 was 

65 μg/L, exceeding the drinking-water standard of 50 μg/L; 

five historical samples showed a maximum concentration of 

7.2 μg/L. In summary, only the dissolved manganese exceedance at site 8 was drought affected. 

Upper Colorado River Basin 

Drought samples were collected at 39 sites in the 

Colorado River Basin (table 12 in Appendix, fig. 4). Average 

percentile for properties and constituents (table 3) indicate 

elevated specific conductance and elevated concentrations of 

chloride, fluoride (tentative), and sulfate relative to nondrought 

Property or constituent Average Q% Number of sites Result

Oxygen, dissolved 44.0 12 Medial

pH 50.4 12 Medial

Specific conductance 73.7 17 Medial

Temperature, water 54.1 17 Medial

Chloride, dissolved 70.2 9 Medial

Fluoride, dissolved 69.2 7 Medial

Silica, dissolved 42.0 6 Medial

Sulfate, dissolved 69.4 9 Medial

Nitrogen, ammonia, dissolved 38.7 8 Medial

Nitrogen, organic plus ammonia, dissolved 55.0 6 Medial

Nitrogen, organic plus ammonia, total recoverable 71.5 3 Medial

Nitrogen, nitrite plus nitrate, dissolved 35.8 10 Medial

Nitrogen, nitrite, dissolved 48.9 7 Medial

Phosphorus, dissolved 58.9 7 Medial

Phosphorus, total recoverable 72.1 3 Medial

Phosphorus, orthophosphate, dissolved 49.0 8 Medial

Carbon, organic, dissolved 60.0 1 ID

Boron, dissolved 48.5 4 Medial

Iron, dissolved 42.3 4 Medial

Manganese, dissolved 41.3 2 ID

Selenium, dissolved 81.0 1 ID

Zinc, dissolved 40.4 2 ID

Table 2. Average percentiles and results for summer 2002 drought water-quality data from sites in the Yampa and White River Basins, 

relative to historical data from July through September, 1978–2002.

[Q%, percentile; Medial, average Q% between 25 and 74.9; ID, insufficient number of sites (fewer than 3) to determine result]

Effect of Drought on Water Quality 11
Little

Yampa

Williams

River

River

Blue

Eagle

Fork

River

River

Roaring

Fork

Colorado

River

Piceance

Roan

Cr

Cr

White

Elkhead

Elk

Snake

R

Cr

River

Dillon

Reservoir

70

70

40

40

13

13

106°

106°

107°

107°

108°

108°

41°

41°

39°

39°

40°

40°

109°

109° Yampa River 

White River BUpper Colora

Grand Junction

SOUTH

PLATTE

DENVE

C O L O R A D O 

GUNNISON RIVER

COLORADO RIVER

Puebl

ARK

Craig

Rifle

Glenwood

Springs

Grand

Junction

Dinosaur

Granby

Dillon

Meeker

Steamboat

Springs

0 25 50 75 MILES0 25 50 75 KILOMETERS

Base from U.S. Geological Survey digital dataAlbers Equal-Area Conic projectionStandard parallels 37°30'N and 40°30'NCentral meridian 105°30'WNorth American Datum of 1927

EXPLANATION

Water-quality samp site—Number is sit number in table 1

31142

7

6

5 4 3 2

1

8

18

17

16

14

13

12

11

10

20

21

22

23

55

57

34

35

36 38

44

46

47

48

49 53 50 54

51 52

56

45

43 41

42

40

39 37

24

25

26

27

28

29

32

33

31

30

58

19

9

15

Figure 4. Sampling sites in the Yampa, White, and Upper Colorado River Basins.
conditions. All other constituents with sufficient data (field 

properties, silica, dissolved and total-recoverable nutrients, 

dissolved iron, and dissolved manganese) indicate medial 

values or concentrations. Other dissolved metals and the only 

total-recoverable metals sampled (iron and manganese) had 

too few sites and associated percentiles for characterization.

Drought samples collected in the basin had water-quality 

exceedances for pH and concentrations of chloride, sulfate, 

nitrite nitrogen, dissolved iron, dissolved manganese, and 

dissolved selenium (table 12). pH exceeded the upper standard of 9.0 at sites 24, 25, 26, and 27. Out of 85 historical 

pH measurements at site 24, 28 showed pH exceedances; no 

historical exceedances were measured at site 25 (13 samples), 

site 26 (8 samples), or site 27 (6 samples); therefore, drought 

probably did not cause the exceedance at site 24, but the 

data are insufficient to assess drought effect for sites 25–27 

because of the potential diurnal fluctuation of pH at these 

sites and variable measurement time. The chloride standard 

of 250 mg/L was exceeded only at site 57 on September 4, 

2002 (292 mg/L); six historical samples showed a maximum 

concentration of 120 mg/L. Thus, historical samples and 

elevated average percentile for chloride in this basin indicate 

that drought may have caused the exceedance at site 57. 

The sulfate water-supply standard of 250 mg/L was 

exceeded at sites 37 (256 and 310 mg/L), 46 (1,910 mg/L), 50 

(338 mg/L), and 53 (259 mg/L). Sites 51, 52, and 54 also had 

sulfate concentrations in excess of 250 mg/L, but no sulfate 

standards have been established for these reaches. Historical 

samples showed sulfate exceedances for 2 out of 29 samples at 

site 37 (maximum 260 mg/L); 15 out of 15 samples at site 46 

(maximum 1,860 mg/L); zero out of 6 samples at site 50 (maximum 240 mg/L); and zero out of 3 samples at site 53 (all in 

1994; maximum 180 mg/L). Historical samples and elevated 

sulfate concentration in this basin indicate that the greater 

exceedance at site 37 and the exceedance at site 50 were likely 

affected by drought; the exceedance at site 53 appears to have 

been affected by drought, but the data are insufficient to allow 

a more definitive conclusion. 

Other drought samples collected in the basin for which 

samples exceeded water-quality standards were nitrite nitrogen, dissolved iron, dissolved manganese, and dissolved 

selenium. Nitrite nitrogen exceeded the chronic standard of 

0.05 mg/L at site 57 (0.081 and 0.117 mg/L). Six historical 

samples from 2000 through 2001 showed no exceedances; 

however, because the 2002 concentrations at this site exceeded 

the historical samples by 5 to 8 times, these exceedances likely 

are affected by drought. 

Dissolved iron exceeded the chronic standard of 300 μg/L 

at site 26 (339 and 383 μg/L); one of seven historical samples 

exceeded this standard (maximum 354 μg/L). Medial concentrations of iron in this basin and these historical data strongly 

indicate that this exceedance is not affected by drought. 

Dissolved manganese exceeded the hardness-based chronic 

standard of 50 μg/L at sites 30 (60 and 115 μg/L) and 31 

(250 μg/L); 2 of 26 historical samples from site 30 showed 

exceedances (68 and 83 μg/L), and 3 of 19 samples from site 

31 showed exceedances (maximum 342 μg/L). Therefore, the 

exceedances at site 30 probably were affected by drought, but 

the exceedance at site 31 probably was not. Dissolved selenium exceeded the chronic standard of 4.6 μg/L at sites 51 

(6.3 μg/L), 52 (8.8 and 11 μg/L), and 54 (5.8 μg/L); this standard was exceeded by 3 of 6 historical samples from site 51 

(maximum 6 μg/L), by 27 of 45 samples from site 52 (maximum 16 μg/L), and by 3 of 6 samples from site 54 (maximum 

6 μg/L), indicating that the dissolved selenium exceedances at 

these sites were not affected by drought. In summary, the data 

indicate drought-affected exceedances only for chloride at site 

57, sulfate at sites 37 and 50, nitrite at site 57, and dissolved 

manganese (chronic standard) at site 30.

Rio Grande Basin 

Drought samples were collected at four sites in the Rio 

Grande Basin (table 13 in Appendix, fig. 5). Average percentiles for properties and constituents (table 4) only indicate a 

medial percentile for water temperature. All other properties 

and constituents had too few data to calculate percentiles for 

basinwide characterization.

The only water-quality exceedance for this basin was for 

dissolved zinc at site 59 (54 μg/L) (table 13), which exceeded 

the acute and chronic standards of 49.3 μg/L and 49.7 μg/L. 

Only two historical samples (1984) were analyzed for dissolved zinc, and they did not exceed these hardness-based 

standards. Therefore, these data are insufficient to indicate 

whether this dissolved zinc exceedance was affected by 

drought. 

Gunnison River Basin 

Drought samples were collected at 21 sites in the Gunnison River Basin (table 14 in Appendix, fig. 5). Average 

percentiles for properties and constituents (table 5) indicate 

elevated specific conductance and elevated concentrations of 

dissolved chloride, dissolved silica, and dissolved sulfate. All 

other constituents with sufficient data—including other field 

properties and most dissolved and total-recoverable nutrients—indicated medial values or concentrations. Fluoride, 

total-recoverable organic plus ammonia nitrogen, and dissolved metals had too few percentiles for calculation. Totalrecoverable metals were not sampled in this basin before 2002; 

and, therefore, no percentiles could be calculated. 

Drought samples collected in the basin for which samples 

exceeded water-quality standards were sulfate, E. coli bacteria, total-recoverable iron, dissolved manganese, and dissolved selenium (table 14). Sulfate exceeded the water-supply 

standard of 480 mg/L at site 74 on September 24, 2002, and 

12 of 55 historical samples (maximum 670 mg/L) exceeded 

this standard. No sulfate standards have been established 

for sites 69 and 73, which showed concentrations from 

608 to 743 mg/L. E. coli bacteria exceeded the standard of 

126 col/100 mL (colonies per 100 milliliters) at sites 69 

Effect of Drought on Water Quality 13
Property or constituent Average Q% Number of sites Result

Oxygen, dissolved 33.3 13 Medial

pH 63.6 15 Medial

Specific conductance 90.0 24 Elevated

Temperature, water 66.1 23 Medial

Chloride, dissolved 95.0 14 Elevated

Fluoride, dissolved 80.1 5 Elevated1

Silica, dissolved 32.7 10 Medial

Sulfate, dissolved 81.6 11 Elevated

Nitrogen, ammonia, dissolved 37.1 10 Medial

Nitrogen, organic plus ammonia, dissolved 68.0 5 Medial

Nitrogen, organic plus ammonia, total recoverable 71.2 5 Medial

Nitrogen, nitrite plus nitrate, dissolved 55.8 11 Medial

Nitrogen, nitrite, dissolved 48.9 10 Medial

Phosphorus, dissolved 56.7 10 Medial

Phosphorus, total recoverable 63.5 6 Medial

Phosphorus, orthophosphate, dissolved 48.1 10 Medial

Carbon, organic, dissolved 87.5 1 ID

Cadmium, dissolved 44.5 2 ID

Chromium, dissolved 50.0 1 ID

Copper, dissolved 66.4 2 ID

Iron, dissolved 51.6 5 Medial

Iron, total recoverable 70.0 2 ID

Lead, dissolved 47.7 2 ID

Manganese, dissolved 73.9 5 Medial

Manganese, total recoverable 93.7 2 ID

Molybdenum, dissolved 63.6 1 ID

Nickel, dissolved 47.7 1 ID

Selenium, dissolved 95.8 1 ID

Silver, dissolved 46.7 2 ID

Zinc, dissolved 30.4 2 ID

Table 3. Average percentiles and results for summer 2002 drought water-quality data from sites in the Upper Colorado River Basin, 

relative to historical data from July through September, 1978–2002.

[Q%, percentile; Medial, average Q% between 25 and 74.9; elevated, average Q% greater than or equal to 75; ID, insufficient number of sites (fewer than 3) to 

determine result; text in bold type highlights elevated average percentiles]

1

 Tentative result because of possible range of Q% for two sites (table 3); minimum values in ranges result in average Q% of 71.7

(medial result).

14 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
Blue

Mesa

Res

Grand

Junction

Delta

Montrose

Telluride Creede

Pagosa

Springs

Silverton

Cortez Durango

Gunnison

Saguache

Alamosa

San

River

River

River

Mc Elmo

Mancos

Miguel

Dolores

Tomichi

Rio

Grande

Saguache

Taylor

Conejos

R

R

R

Cr

Cr

Cr

R

Los

Juan

San

Piedra

Pinos

R

R

R

Disappointment

Cr

Grand Junction

SOUTH

PLATTE

RIVER

DENVER

C O L O R A D O 

GUNNISON RIVER

COLORADO RIVER

Pueblo ARKANSAS RIVE

Base from U.S. Geological Survey digital dataAlbers Equal-Area Conic projectionStandard parallels 37°30'N and 40°30'NCentral meridian 105°30'WNorth American Datum of 1927

Animas

0 25 50 75 MILES0 25 50 75 KILOMETERS

77

77

76

75

68 67

88

87

72

71

92 62

61

60

102

101

100

89

91

93

94 95

96

99 98

97

84 90

59

86

85

69

78

73

70

74

66

65

64

63

83 82 81

80

79

Gunnison Rive

88

Dolores River 

90

San Juan River 

61

Rio Grande Ba

EXPLANATION

Water-quality sampling  is site number in table 1

39°

39°

38°

37°

38°

37°

109°

108°

107°

106°

106° 107°

109° 108°

550

550

285

285

160

160

160

666

50

Figure 5. Sampling sites in the Rio Grande, Gunnison, Dolores, and San Juan River Basins.
(580 and 210 col/100 mL), 72 (210 col/100 mL), 73 (280 

and 210 col/100 mL), and 82 (800 col/100 mL); however, 

the effect of drought cannot be determined for these sites 

because of insufficient historical data. The chronic standard 

of 1,500 μg/L for total-recoverable iron was exceeded at 

sites 71 (4,050 μg/L) and 72 (2,640 μg/L); two of two 2001 

historical samples for site 71 exceeded this standard (maximum 6,520 μg/L), and two of three historical samples for 

site 72 exceeded this standard (maximum 19,900 μg/L). The 

hardness-based, chronic standard for dissolved manganese 

was exceeded at site 67 on August 7, 2002 (57 μg/L); zero 

of nine historical samples exceeded this standard (maximum 

35 μg/L). The hardness-based chronic dissolved selenium 

standard of 4.6 μg/L was exceeded at site 70 on August 8 

(5.0 μg/L) and September 11, 2002 (7 μg/L). The fixed chronic 

standard of 6.0 μg/L was exceeded at site 74 on September 

24, 2002 (8 μg/L). For site 70, 6 of 13 historical samples for 

the seasonal period of record and 31 of 50 samples for site 74 

exceeded these standards (maximum 8 and 25 μg/L, respectively). In summary, the only exceedance that was affected by 

drought was dissolved manganese (chronic standard) at site 

67. The data indicate that the exceedances for sulfate, total 

iron, and dissolved selenium were not affected by drought.

Dolores River Basin 

Drought samples were collected at five sites in the Dolores River Basin (table 15 in Appendix, fig. 5). Average percentiles (table 6) indicate that specific conductance was elevated 

and that water temperature had medial values. pH, chloride, 

fluoride, silica, and sulfate had too few sites for basin characterization, although all had high average percentiles, indicating 

elevated levels for the available data.

Property or constituent Average Q% Number of sites Result

Oxygen, dissolved 38.2 1 ID

pH 94.6 1 ID

Specific conductance 62.9 1 ID

Temperature, water 26.6 3 Medial

Chloride, dissolved 97.1 1 ID

Fluoride, dissolved 97.1 1 ID

Silica, dissolved 2.9 1 ID

Sulfate dissolved 68.6 1 ID

Nitrogen, ammonia, dissolved 40.3 1 ID

Nitrogen, organic plus ammonia, dissolved 65.4 1 ID

Nitrogen, organic plus ammonia, total recoverable 56.8 1 ID

Nitrogen, nitrite plus nitrate, dissolved 45.5 1 ID

Nitrogen, nitrite, dissolved 50.0 1 ID

Phosphorus, dissolved 10.8 1 ID

Phosphorus, total recoverable 4.1 1 ID

Phosphorus, orthophosphate, dissolved 10.0 1 ID

Bacteria, fecal coliform 40.9 1 ID

Iron, dissolved 29.6 1 ID

Manganese, dissolved 86.0 1 ID

Table 4. Average percentiles and results for summer 2002 drought water-quality data from sites in the Rio Grande Basin, relative to 

historical data from July through September, 1978–2002.

[Q%, percentile; medial, average Q% between 25 and 74.9; elevated, average Q% greater than or equal to 75; depressed, average Q% less than 25; ID, insufficient number of sites (fewer than 3) to determine result]

16 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
E. coli bacteria was the only constituent showing a waterquality exceedance in this basin: site 87 exceeded the standard 

of 126 col/100 mL on August 6, 2002 (210 col/100 mL). However, because there are no historical samples for this constituent at this site, no conclusion can be made about the effect of 

drought on this exceedance. 

San Juan River Basin 

Drought samples were collected at 14 sites in the San 

Juan River Basin (table 16 in Appendix, fig. 5). Average 

percentiles (table 7) indicate that specific conductance and 

concentrations of chloride, fluoride, and sulfate were elevated 

and likely were affected by drought. pH and water temperature values and silica concentrations indicated medial values. 

Dissolved and total-recoverable nutrients had too few sites 

for characterization. Metals were sampled too infrequently to 

allow calculation of reliable percentiles.

Drought samples exceeded water-quality standards for 

sulfate, E. coli bacteria, and dissolved iron (table 16). The 

sulfate standard of 250 mg/L was exceeded at site 102 on 

September 6, 2002 (419 mg/L); no historical samples exist for 

this constituent at this site. The standard of 126 col/100 mL 

for E. coli bacteria was exceeded at site 94 on August 2, 

2002 (140 col/100 mL), at site 95 on September 4, 2002 

Property or constituent Average Q% Number of sites Result

Oxygen, dissolved 35.5 4 Medial

pH 70.8 5 Medial

Specific conductance 82.1 9 Elevated

Temperature, water 47.5 9 Medial

Chloride, dissolved 79.0 3 Elevated

Fluoride, dissolved 77.8 1 ID

Silica, dissolved 75.9 3 Elevated1

Sulfate, dissolved 84.4 3 Elevated

Nitrogen, ammonia, dissolved 35.8 3 Medial

Nitrogen, organic plus ammonia, dissolved 48.6 3 Medial

Nitrogen, organic plus ammonia, total recoverable 50.0 1 ID

Nitrogen, nitrite plus nitrate, dissolved 44.0 3 Medial

Nitrogen, nitrite, dissolved 41.9 3 Medial

Phosphorus, dissolved 49.9 3 Medial

Phosphorus, total recoverable 64.3 3 Medial

Phosphorus, orthophosphate, dissolved 36.8 3 Medial

Cadmium, dissolved 48.1 1 ID

Copper, dissolved 76.9 1 ID

Iron, dissolved 27.9 2 ID

Lead, dissolved 46.2 1 ID

Manganese, dissolved 25.6 1 ID

Selenium, dissolved 68.3 2 ID

Silver, dissolved 93.3 1 ID

Zinc, dissolved 42.3 1 ID

Table 5. Average percentiles and results for summer 2002 drought water-quality data from sites in the Gunnison River Basin relative to 

historical data from July through September, 1978–2002.

[Q%, percentile; Medial, average Q% between 25 and 74.9; elevated, average Q% greater than or equal to 75; ID, insufficient number of sites (fewer than 3) to 

determine result; text in bold type highlights elevated average percentiles]

1

 Tentative result because of possible range of Q% for one site (table 5); minimum value in range results in average Q% of 74.7 (medial result).

Effect of Drought on Water Quality 17
(380 col/100 mL), at site 97 (220 and 260 col/100 mL) 

August 7 and September 18, 2002, at site 98 on September 

10, 2002 (540 col/100 mL), and at site 99 on August 7 and 

September 10, 2002 (220 and 1,100 col/100 mL); no historical data exist for this constituent at any of these sites, so the 

effect of drought cannot be assessed. The monthly dependent, chronic standard of 1,286 μg/L for dissolved iron at 

site 92 was exceeded on July 31, 2002, with a concentration 

of 1,900 μg/L. Seven historical samples show zero exceedances for dissolved iron (maximum 1,200 μg/L), although the 

maximum historical value is more than half of the drought 

exceedance. In summary, it is unknown if any of the standard 

exceedances were affected by drought. 

South Platte River Basin 

Drought samples were collected at 23 sites in the South 

Platte River Basin (table 17 in Appendix, fig. 6). Average 

percentiles (table 8) indicated medial values and concentrations for field properties, most dissolved and total-recoverable 

nutrients, dissolved organic carbon, and some dissolved trace 

metals (copper, iron, manganese, and silver). Too few sites 

had reliable percentiles to allow characterization of dissolved 

organic plus ammonia nitrogen, total-recoverable organic 

carbon, total-recoverable iron, dissolved lead, and dissolved 

nickel.

Drought samples exceeded water-quality standards for 

pH, dissolved ammonia, dissolved nitrite, dissolved copper, 

and dissolved manganese (table 17). The upper standard of 

9.0 SU for pH was exceeded at sites 108 (9.1) and 109 (9.1) 

on September 9, 2002, and at site 119 (9.3) on September 10, 

2002; historical samples for site 108 (maximum pH of 8.2) 

show 1 out of 47 pH measurements was above the acceptable 

range, but that measurement was below the 6.5 standard; zero 

of 6 historical samples for site 109 exceeded the pH standard (maximum 7.8); 2 of 58 historical samples for site 119 

(maximum 8.5) had pH less than the 6.5 standard, but none 

exceeded the upper standard. Therefore, although all three of 

the upper-standard pH exceedances appear to be affected by 

drought, the problem of diurnal variation in pH and variable 

measurement times (Chafin, 2002) preclude a valid basis for 

comparing drought and historical measurements, so no causative conclusion can be made. 

The reach-specific chronic standard for dissolved ammonia was exceeded in drought samples at sites 104, 106, 108, 

109, 116, and 122 (table 17). Sites 104, 106, 108, and 122 also 

exceeded their reach-specific chronic standards for ammonia 

more than two-thirds of the time during the seasonal period of 

record, and site 116 exceeded the standard about one-half of 

the time. The effect of drought on site 109 is uncertain because 

one ammonia concentration in six exceeded the standard during the seasonal period of record. These results indicate that 

the chronic ammonia exceedances in the South Platte River 

Basin during 2002 were not directly affected by drought. 

Property or constituent Average Q% Number of

sites Result

pH 88.8 2 ID

Specific conductance 85.7 5 Elevated

Temperature, water 36.8 5 Medial

Chloride, dissolved 95.0 2 ID

Fluoride, dissolved 82.0 2 ID

Silica, dissolved 95.0 2 ID

Sulfate dissolved 86.5 2 ID

Table 6. Average percentiles and results for summer 2002 

drought water-quality data from sites in the Dolores River Basin 

relative to historical data from July through September, 1978–2002.

[Q%, percentile; medial, average Q% between 25 and 74.9; elevated, average 

Q% greater than or equal to 75; ID, insufficient number of sites (fewer than 3) 

to determine result; text in bold type highlights elevated average percentiles]

Property or constituent Average Q% Number of 

sites Result

pH 43.8 4 Medial

Specific conductance 95.2 6 Elevated

Temperature, water 53.3 7 Medial

Chloride, dissolved 86.0 4 Elevated

Fluoride, dissolved 92.9 3 Elevated

Silica, dissolved 41.8 4 Medial

Sulfate, dissolved 88.2 6 Elevated

Nitrogen, ammonia,

dissolved 30.6 1 ID

Nitrogen, organic plus

ammonia, total

recoverable 26.1 1 ID

Nitrogen, nitrite plus 

nitrate, dissolved 94.7 1 ID

Phosphorus, dissolved 34.8 1 ID

Phosphorus, total

recoverable 27.4 1 ID

Table 7. Average percentiles and results for summer 2002 

drought water-quality data from sites in the San Juan River Basin, 

relative to historical data from July through September, 1978–2002.

[Q%, percentile; medial, average Q% between 25 and 50; elevated, average 

Q% greater than or equal to 75; ID, insufficient number of sites (fewer than 3) 

to determine result; text in bold type highlights elevated average percentiles]

18  Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
Cache Poudre

River

South Platte

River

La

St. Vrain

Thompson R Big

Cr

Cr Creek Box

Creek

 Elder Cr

Creek

KiowaBeaver

Bijou

Clear Cr

Cherry

Cr

South

Platte

River

Boulder

70

34

25

25

76

76

70

36

285

0 25 50 75 MILES0 25 50 75 KILOMETERS

EXPLANATION

Water-quality sam site—Number is s number in table 1

117

117

116

115

112 111

106

103

120

104

105

113 114

125

122 123

110, 124

107

121

119

108,109

118

Julesburg

Fort

Morgan

Fort Collins

Estes

Park

Greeley

Boulder

Golden

DENVER

Castle Rock

41°

40° 40°

39°

106°

106°

105°

105°

104°

104°

103°

103°

39°

Grand Junction

SOUTH PLAT

DEN

C O L O R A D O 

GUNNISON RIVER

COLORADO RIVER

Pue

A

Base from U.S. Geological Survey digital data Albers Equal-Area Conic projectionStandard parallels 37°30'N and 40°30'NCentral meridian 105°30'WNorth American Datum of 1927

Figure 6. Sampling sites in the South Platte River Basin.
Property or constituent Average Q% Number of sites Result

Oxygen, dissolved 43.7 12 Medial

pH 53.0 12 Medial

Specific conductance 70.9 13 Medial

Temperature, water 56.3 15 Medial

Chloride, dissolved 74.9 9 Medial

Silica, dissolved 66.7 7 Medial

Sulfate, dissolved 59.3 9 Medial

Nitrogen, ammonia, dissolved 43.7 11 Medial

Nitrogen, organic plus ammonia, dissolved 83.9 1 ID

Nitrogen, organic plus ammonia, total recoverable 35.2 6 Medial

Nitrogen, nitrite plus nitrate, dissolved 68.2 12 Medial

Nitrogen, nitrite, dissolved 60.2 7 Medial

Phosphorus, dissolved 46.2 8 Medial

Phosphorus, total recoverable 46.0 9 Medial

Phosphorus, orthophosphate, dissolved 53.4 10 Medial

Carbon, organic, dissolved 58.8 3 Medial

Carbon, organic, total recoverable 25.9 1 ID

Copper, dissolved 62.3 5 Medial

Iron, dissolved 33.4 10 Medial

Iron, total recoverable 42.0 2 ID

Lead, dissolved 48.5 1 ID

Manganese, dissolved 63.5 6 Medial

Nickel, dissolved 50.0 1 ID

Silver, dissolved 45.9 4 Medial

Table 8. Average percentiles and results for summer 2002 drought water-quality data from sites in the South Platte 

River Basin relative to historical data from July through September, 1978–2002.

[Q%, percentile; Medial, average Q% between 25 and 74.9; elevated, average Q% greater than or equal to 75; ID, insufficient number of sites 

(fewer than 3) to determine result]

20 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
Dissolved nitrite nitrogen exceeded the reach-specific 

standard of 1.0 at site 106 on August 13, 2002 (1.21 mg/L); 

one of 22 historical samples exceeded the standard (maximum 

1.1 mg/L), making it likely that the drought-sample exceedance was affected by drought. Dissolved copper exceeded 

the hardness-based acute and chronic standards at site 110 on 

August 6, 2002 (1.9 μg/L); six historical samples showed no 

exceedances, but four of these samples had reported concentrations of less than 2 μg/L; therefore, no conclusion can be 

reached about the effect of drought on the dissolved copper 

exceedances at site 110. The drinking-water standard for 

dissolved manganese was exceeded at site 120 on August 22 

(69 μg/L) and September 16, 2002 (63 μg/L), but there are 

no historical data for manganese for this site, so the effect of 

drought cannot be determined. 

In summary, the 2002 drought appears to have caused 

an exceedance for nitrite at one site when compared to the 

seasonal period of record for all sites. 

Arkansas River Basin 

Drought samples were collected at 23 sites in the Arkansas River Basin (table 18 in Appendix, fig. 7). Percentiles for 

specific conductance (table 9) indicated elevated values for 

specific conductance and sulfate concentration; concentrations of total-recoverable iron and manganese (tentative) were 

depressed. Dissolved oxygen, pH, most dissolved and totalrecoverable nutrients, fecal-coliform bacteria, dissolved cadmium, iron, lead, manganese, and zinc, and total-recoverable 

cadmium, chromium, and zinc indicated medial values and 

concentrations. Too few sites had reliable percentiles for totalrecoverable organic plus ammonia nitrogen; dissolved arsenic, 

chromium, copper, nickel, selenium, and silver; and totalrecoverable copper, mercury, and nickel.

Drought samples indicate water-quality exceedances for sulfate, E. coli bacteria, fecal-coliform bacteria, 

total-recoverable iron, dissolved manganese, and dissolved 

selenium (table 18). Sulfate exceeded the reach-specific 

standard of 1,078 μg/L at sites 144 (1,080 μg/L) and 145 

(1,590 μg/L); historical samples showed no exceedances in 

5 samples at site 144 (maximum 940 μg/L) and 1 exceedance 

in 10 samples at site 145 (maximum 1,440 μg/L). Historicalsample exceedances are inconclusive indicators of drought 

effect on sulfate exceedance at site 144; however, elevated 

average percentile for sulfate in this basin indicates that 

drought could have caused some exceedances of water-quality 

standards and probably did so for the drought samples 

collected at sites 144 and 145.

Most sites (16 of 23) had samples with E. coli colonies 

that exceeded the standard of 126 col/100 mL (maximum 

3,900 colonies per 100 mL); however, all historical samples 

were collected in 2001 and no more than three samples 

were collected at each site. Therefore, no conclusion can be 

made about the effect of drought on these E. coli exceedances. Most sites (14 of 23) also had drought samples with 

fecal-coliform colonies that exceeded the general standard of 

200 col/100 mL. More than one-half of the samples collected 

at these sites historically had exceedances that generally were 

substantially larger than drought samples (except for site 143, 

which had no historical data, and for site 131, which had 

one exceedance in seven historical samples and for which 

drought-sample colonies substantially exceeded the maximum 

historical count by 3 to 25 times). Therefore, exceedances of 

water-quality standards for fecal coliform for 14 of 18 samples 

collected in this basin probably were not affected by drought 

conditions.

The reach-specific chronic standard of 2,690 μg/L for 

total-recoverable iron was exceeded at site 140 (3,840 μg/L); 

historical data for the seasonal period of record show 

11 exceedances in 18 samples (maximum 54,100 μg/L), indicating that the drought-sample exceedance was not affected by 

drought conditions—a conclusion supported by the depressed 

average percentile for total-recoverable iron. 

The chronic dissolved manganese standard of 50 μg/L 

was exceeded at sites 130 (162 μg/L), 131 (141 μg/L), 133 

(52 μg/L), 141 (71 μg/L), 143 (115 μg/L), and 145 (133 μg/L); 

historical samples show one exceedance out of 14 samples 

at site 130 (maximum 80 μg/L), zero out of 12 at site 131 

(maximum 30 μg/L); 23 out of 45 at site 133 (maximum 

150 μg/L); zero out of 9 at site 141; and zero out of 10 at site 

145 (maximum 30 μg/L). There are no historical data for site 

143. These data indicate that the drought-sample exceedance 

at site 133 was not affected by drought conditions, whereas 

those at sites 130, 131, 141, and 145 probably were, and those 

at site 143 are indeterminate.

The acute and chronic standards for dissolved selenium 

were exceeded at site 131 (28 μg/L); the variable chronic 

standard also was exceeded at sites 135 (15 μg/L) and 136 

(14 μg/L). Historical data indicate no exceedances for site 131 

(11 samples; maximum 6 μg/L) and 135 (4 samples; maximum 9 μg/L); site 136 had one exceedance out of 25 samples 

(maximum 7 μg/L). These data indicate that exceedances at 

sites 131 and 136 probably were affected by drought, but the 

effect at site 135 is uncertain. 

In summary, drought conditions probably contributed to 

exceedances of water-quality standards for sulfate at site 144 

and site 145. Fourteen of 18 exceedances in fecal-coliform 

colonies probably were not affected by drought, but two 

exceedances (site 131) possibly were affected by drought and 

two (site 143) could not be assessed for cause. The chronic 

standard for total-recoverable iron at site 140 probably was not 

affected by drought. The chronic dissolved manganese exceedance at site 133 probably was not affected by drought conditions, whereas those at sites 130, 131, 141, and 145 probably 

were, and the exceedance at site 143 cannot be assessed for 

cause. Exceedances in dissolved selenium at sites 131 (acute 

and chronic) and 136 (chronic) probably were affected by 

drought, but the chronic exceedance at site 135 could not be 

characterized.

Effect of Drought on Water Quality 21
Arkansas

Fountain Fourmile Cr

River

Creek

Creek

Horse

Rush

Big

Creek Creek Sandy

Black Squirrel

Creek

Purgatoire

River

River

River

St.

R

Apishapa

Huerfano Charles

Chalk Cr

John Martin

Reservoir

106°

105°

104°

104° 105°

106°

103°

103°

39°

38°

37°

39°

39°

Base from U.S. Geological Survey digital data Albers Equal-Area Conic projectionStandard parallels 37°30'N and 40°30'NCentral meridian 105°30'WNorth American Datum of 1927

0 25 50 75 MILES0 25 50 75 KILOMETERS

EXPLANATION

Water-quality sampling site—Number is site number in table 1

142

142 141

140

139

138 137 135 136

132

134

133

131

130 129

128

127

126

143

144

145 148

147

146

Gran

GUNN

COLORA

Leadville

Salida

Cañon City

Fountain

Pueblo

Walsenburg

Trinidad

La Junta

Lamar

Limon

Las Animas

Kit Carson

Colorado

Springs

25

70

50

50

40

24

24

350

285

Figure 7. Sampling sites in the Arkansas River Basin.
Property or constituent Average Q% Number of sites Result

Oxygen, dissolved 55.5 10 Medial

pH 64.9 11 Medial

Specific conductance 81.2 20 Elevated

Temperature, water 63.8 19 Medial

Fluoride, dissolved 49.6 6 Medial

Sulfate dissolved 86.7 6 Elevated

Nitrogen, ammonia, dissolved 25.1 5 Medial

Nitrogen, organic plus ammonia, total recoverable 46.9 1 ID

Nitrogen, nitrite plus nitrate, dissolved 54.7 6 Medial

Phosphorus, total recoverable 47.9 4 Medial

Phosphorus, orthophosphate, dissolved 51.4 4 Medial

Bacteria, fecal coliform 48.7 6 Medial

Arsenic, dissolved 31.0 1 ID

Cadmium, dissolved 48.2 4 Medial

Cadmium, total recoverable 47.6 4 Medial

Chromium, dissolved 95.7 1 ID

Chromium, total recoverable 51.8 5 Medial

Copper, dissolved 46.4 1 ID

Copper, total recoverable 62.8 1 ID

Iron, dissolved 25.6 7 Medial

Iron, total recoverable 20.4 6 Depressed

Lead, dissolved 46.8 5 Medial

Manganese, dissolved 42.6 5 Medial

Manganese, total recoverable 24.4 6 Depressed1

Mercury, total recoverable 47.6 1 ID

Nickel, dissolved 79.3 1 ID

Nickel, total recoverable 89.3 1 ID

Selenium, dissolved 87.7 2 ID

Silver, dissolved 48.3 1 ID

Zinc, dissolved 59.6 6 Medial

Zinc, total recoverable 28.3 6 Medial

1

 Tentative result because of possible range of Q% for four sites (table 18 in Appendix); maximum values in ranges result in average Q% of 25.6 

(medial result).

[Q%, percentile; medial, average Q% between 25 and 74.9; elevated, average Q% greater than or equal to 75; depressed, average Q% less than 25; 

ID, insufficient number of sites (fewer than 3) to determine result; text in bold type highlights depressed or elevated average percentiles]

Table 9. Average percentiles and results for summer 2002 drought water-quality data from sites in the Arkansas River 

Basin relative to historical data from July through September, 1978–2002.

Effect of Drought on Water Quality 23
Statewide Overview

A summary of characterization of percentiles for all 

drought samples collected in Colorado during summer 2002 

(table 10) indicates that few measured properties or constituents were elevated or depressed in concentration or value 

on a widespread basis. Specific conductance was elevated 

in five of the seven basins (or basin groups) that had sufficient data for characterization (that is, those not showing 

“ID” or “--” in table 10); although specific conductance was 

medial in the Yampa and White and the South Platte River 

Basins, large average percentiles of 73.7 (table 2) and 70.9 

(table 8) indicate that specific conductance likely was affected 

by drought in those basins. For the 95 sites for which a 

specific-conductance percentile could be calculated, the average percentile of 81.8 indicates substantial elevation on a statewide basis. Similarly, chloride concentrations were elevated 

in three of five basins with sufficient data; although chloride 

concentration was medial in the Yampa and White and the 

South Platte River Basins, above-median average percentiles 

of 70.2 (table 2) and 74.9 (table 8) indicate that chloride concentration generally was affected by drought in those basins, 

too (average percentile of 83.7 for 43 sites). Sulfate concentration was elevated in four of six basins with sufficient data; 

the Yampa and White and the South Platte River Basins had 

medial concentrations; an above-median average percentile 

of 69.4 (table 2) in the Yampa and White River Basin group 

indicates some increase in sulfate concentration there; sulfate 

concentration was slightly increased in the South Platte River 

Basin (average percentile equals 59.3; table 8). All basins 

that exhibited elevated concentrations of chloride and sulfate 

also exhibited elevated specific conductance. The widespread 

elevation of specific conductance and concentrations of chloride and sulfate indicates that salinity generally was affected 

by drought in Colorado streams during July through September 2002, undoubtedly because streamflow at most sites was 

dominated by base flow of ground water, which usually has 

considerable salinity compared to runoff from precipitation 

(Winter and others, 1999).

Fluoride concentrations were elevated in two (tentative 

in Upper Colorado; San Juan) of four basins with sufficient 

data to characterize, and two of the other basins (Yampa/White 

and Arkansas) had medial concentrations. Both basins with 

elevated concentrations of fluoride had elevated specific conductance and concentrations of chloride and sulfate, which is 

consistent with a ground-water source for fluoride; however, 

the Arkansas River Basin had medial concentrations of fluoride despite having elevated specific conductance and sulfate 

concentrations. The reasons for this apparent contradiction 

cannot be readily determined but may be the result of basin 

geology, an artifact of sampling-site distribution, or both.

Dissolved and total-recoverable nutrients (nitrogen and 

phosphorus) showed medial (and near medial) concentrations 

in the five basins with sufficient data to characterize. However, dissolved ammonia concentrations were below median 

concentrations (average percentile less than 50) in the five 

basins with sufficient data to characterize; the Arkansas River 

Basin nearly had depressed average percentile (25.1; table 9). 

The widespread below-median concentration of dissolved 

ammonia indicates that drought affected the ammonia concentrations. The overall pronounced consistency of medial 

concentrations of nutrients probably is the result of nutrient 

uptake by aquatic plants upstream from most sites that were 

sampled—which tends to keep nutrient concentrations low 

during summer, low-flow conditions (Sprague and others, 

2002). This mechanism would explain why reduced dilution of 

nutrients did not cause elevated nutrient concentration at some 

sites that receive sewage-wastewater effluent. 

Dissolved organic carbon could be characterized only 

for the South Platte River Basin, which had medial concentrations. E. coli bacteria could not be characterized for any basin. 

Fecal-coliform bacteria could be characterized only for the 

Arkansas River Basin, which had medial percentiles.

Dissolved and total-recoverable concentrations of 

metals—except those for dissolved iron and manganese—

could only be characterized for one constituent each in four 

separate basins: the Arkansas River Basin had medial concentrations of cadmium (dissolved and total-recoverable), totalrecoverable chromium, dissolved lead, and zinc (dissolved 

and total-recoverable); the Yampa and White River Basin 

had medial concentrations of dissolved boron; and the South 

Platte River Basin had medial concentrations of dissolved 

copper and silver. Dissolved iron showed medial concentrations in the Yampa and White, Upper Colorado, South Platte, 

and Arkansas Basins. Dissolved manganese showed medial 

concentrations in the Upper Colorado, South Platte, and 

Arkansas Basins. Total-recoverable iron and manganese could 

only be characterized for the Arkansas River Basin, which had 

depressed concentrations of both constituents (tentative for 

manganese). 

Medial concentrations of all of these metals except for 

copper, iron, and manganese result from the fact that most 

historical and drought samples had censored, recensored, or 

low (near-censored) concentrations, probably due to limitations of source and solubility. Medial concentrations of dissolved copper, iron, and manganese possibly resulted from the 

fact that these metals are abundant enough in drainage basins 

(from natural and anthropogenic sources) to dissolve into the 

runoff component of streamflow in concentrations similar to 

those found in ground water; if so, the greater dominance of 

ground-water base flow during drought conditions would not 

be expected to shift concentrations substantially compared to 

historical summer periods when runoff contributed a larger 

fraction of streamflow. 

The depressed concentrations of total-recoverable iron 

and manganese in the Arkansas River Basin during drought 

conditions of 2002 probably were the result of reduced landsurface washoff of sediment containing oxyhydroxides of 

these metals; the relatively low average percentile of 28.3 

for total-recoverable zinc indicates the same effect, although 

censored and recensored concentrations of total-recoverable 

zinc for many drought and historical samples could preclude 

24 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
River basin

Property or constituent

Yampa

 and 

White

(table 2)

Upper

Colorado 

(table 3)

Rio

Grande 

(table 4)

Gunnison 

(table 5)

Dolores 

(table 6)

San

Juan

(table 7)

South

Platte

(table 8)

Arkansas

(table 9)

Oxygen, dissolved Medial Medial ID Medial -- -- Medial Medial

pH Medial Medial ID Medial ID Medial Medial Medial

Specific conductance Medial Elevated ID Elevated Elevated Elevated Medial Elevated

Temperature, water Medial Medial Medial Medial Medial Medial Medial Medial

Chloride, dissolved Medial Elevated ID Elevated ID Elevated Medial --

Fluoride, dissolved Medial Elevated1 ID ID ID Elevated -- Medial

Silica, dissolved Medial Medial ID Elevated1 ID Medial Medial --

Sulfate, dissolved Medial Elevated ID Elevated ID Elevated Medial Elevated

Nitrogen, ammonia, dissolved Medial Medial ID Medial -- ID Medial Medial

Nitrogen, organic plus ammonia, dissolved Medial Medial ID Medial -- -- ID --

Nitrogen, organic plus ammonia,

total recoverable Medial Medial ID ID -- ID Medial ID

Nitrogen, nitrite plus nitrate, dissolved Medial Medial ID Medial -- ID Medial Medial

Nitrogen, nitrite, dissolved Medial Medial ID Medial -- -- Medial --

Phosphorus, dissolved Medial Medial ID Medial -- ID Medial --

Phosphorus, total recoverable Medial Medial ID Medial -- ID Medial Medial

Phosphorus, orthophosphate, dissolved Medial Medial ID Medial -- -- Medial Medial

Carbon, organic, dissolved ID ID -- -- -- -- Medial --

Bacteria, fecal coliform -- -- ID -- -- -- -- Medial

Boron, dissolved Medial -- -- -- -- -- -- --

Cadmium, dissolved -- ID -- ID -- -- -- Medial

Cadmium, total recoverable -- -- -- -- -- -- -- Medial

Chromium, total recoverable -- -- -- -- -- -- -- Medial

Copper, dissolved -- ID -- ID -- -- Medial ID

Iron, dissolved Medial Medial ID ID -- -- Medial Medial

Iron, total recoverable -- ID -- -- -- -- ID Depressed

Lead, dissolved -- ID -- ID -- -- ID Medial

Manganese, dissolved ID Medial ID ID -- -- Medial Medial

Manganese, total recoverable -- ID -- -- -- -- -- Depressed1

Nickel, dissolved -- ID -- -- -- -- ID ID

Silver, dissolved -- ID -- ID -- -- Medial ID

Zinc, dissolved ID ID -- ID -- -- -- Medial

Zinc, total recoverable -- -- -- -- -- -- -- Medial

Table 10. Summary of characterization of percentiles for properties and constituents in drought samples collected from sites in 

Colorado during summer 2002 compared to 1978–2002.

[Medial, average basin percentile between 25 and 74.9; elevated, average basin percentile greater than or equal to 75; depressed, average basin percentile 

less than 25; ID, insufficient number (less than 3) of sites to calculate average percentile; --, constituent not measured in drought samples or had insufficient 

number (fewer than 20) of historical and drought samples at any site to calculate percentile. Constituents for which there were too few or no drought samples 

for all study river bains are not included in this table; text in bold highlights depressed or elevated average percentiles]

1

 Tentative (borderline) result; see table listed in column heading for details.

Effect of Drought on Water Quality 25
the ability of average percentile to indicate depressed concentration.

In total, 115 exceedances of 2002 Colorado water-quality 

standards were identified in the 246 drought samples collected at 148 sites. Constituents showing exceedances of water 

quality-standards were pH (all 9.0 exceedances; 9 samples), 

chloride (1 sample), sulfate (9 samples), dissolved ammonia 

(10 samples), dissolved nitrite nitrogen (3 samples), E. coli

bacteria (34 samples, 20 in the Arkansas River Basin), fecalcoliform bacteria (18 samples, all in the Arkansas River 

Basin), dissolved copper (1 sample), dissolved iron (3 samples), total-recoverable iron (3 samples), dissolved manganese 

(13 samples), dissolved selenium (10 samples), and dissolved 

zinc (1 sample). Of these 115 exceedances, historical data 

were sufficient to conclude that 21 probably were affected 

by drought, 39 probably were not affected by drought, and 

55 were of indeterminate nature (that is, were considered to 

be possibly or apparently affected by drought, or data were 

insufficient for judging). Excluding all of the exceedances 

of E. coli and fecal-coliform bacteria (52) because of their 

overrepresentation in the Arkansas River Basin, 19 of the total 

63 exceedances probably were affected by drought, 25 probably were not, and 19 were of indeterminate nature. Therefore, based on the first two categories, about 38 percent of the 

exceedances probably would have occurred under nondrought 

conditions. However, eight dissolved manganese exceedances 

were affected by drought compared to two that were considered not to be affected by drought, and sulfate showed five 

exceedances that were affected by drought and two that were 

not affected by drought. Overall, the data indicate that most 

water-quality exceedances probably were not drought related 

but that drought affected concentrations of some constituents 

(especially dissolved manganese and sulfate) were enough to 

cause local exceedances of water-quality standards.

Specific-conductance values indicate that the San Juan 

River Basin (average percentile 95.2; table 7) experienced 

the greatest effects of drought on water quality during summer 2002 compared to other basins in Colorado, followed by 

the Upper Colorado (90.0; table 3) and Dolores River (85.7; 

table 6) Basins. The South Platte River Basin (70.9; table 8) 

experienced the least effect of drought, and the Yampa and 

White River Basin group (73.7; table 2) had the second smallest drought effect. The Gunnison River (82.1; table 5) and 

Arkansas River (81.2; table 9) Basins showed an intermediate 

drought effect. The Rio Grande Basin had insufficient data to 

determine the relative effect of drought on water quality.

Summary

During 2002, Colorado experienced the State’s worst 

drought since 1977. To determine the effects of this drought 

on the water quality of streams in the State during the summer 

of 2002, a variety of State and local governments cooperated with the U.S. Geological Survey to collect water-quality 

samples at 148 stream sites in all major river basins in 

Colorado. Water samples were analyzed for field properties, 

major ions, nutrients, organic carbon, bacteria, and dissolved 

metals at all sites, although individual constituents in these 

categories varied among basins. At some sites, water samples 

also were analyzed for total-recoverable metals. In 2003, the 

U.S. Geological Survey, in cooperation with the Colorado 

Department of Public Health and Environment, analyzed these 

data to determine the general effects of drought on the water 

quality of streams in Colorado during summer 2002. This 

report summarizes streamflow for 2002 relative to the 1978 

through 2001 period and presents percentiles of concentrations 

of water-quality constituents from the summer of 2002 relative 

to historical data for each site for the months of July through 

September during 1978 through 2001. Exceedances of Colorado water-quality standards for constituents sampled during 

summer 2002 are included.

Mean annual streamflow was analyzed at 134 sites in 

Colorado for water years 1978–2002. Mean annual streamflow 

for 2002 had an average percentile of 29.4 percent during this 

period, indicating that streamflow in Colorado during 2002 

was substantially less than median percentile streamflow for 

1978–2002. Mean summer (July–September) streamflow for 

2002 was analyzed for 146 sites in Colorado, and percentiles 

averaged 7.6 percent when compared to summer streamflow 

for 1978–2002 for 134 sites across Colorado. Because mean 

summer streamflow for 2002 had a substantially smaller average percentile (7.6 percent) than did mean annual streamflow 

for 2002 (29.4 percent), the effect of drought on streamflow 

was greater during summer 2002 than during water year 2002.

Drought samples were collected at 8 sites in the Yampa 

River Basin and at 11 sites in the White River Basin. Average 

percentiles (for July–September 1978–2002) for constituents 

collected in both basins indicate medial (in interquartile range 

of 25–75) values or concentrations for all constituents with 

sufficient data—including field properties, chloride, fluoride, silica, and sulfate, most dissolved and total-recoverable 

nutrients, and dissolved boron and iron. The only exceedances 

of 2002 Colorado water-quality standards were for pH (upper 

standard of 9.0 SU) at one site and for dissolved manganese at 

another.

Drought samples were collected at 39 sites in the Upper 

Colorado River Basin. Average percentiles for properties and 

constituents indicate elevated (in upper quartile range of 75 or 

greater) specific conductance and elevated concentrations of 

chloride, fluoride (tentative), and sulfate. All other constituents with sufficient data (field properties, silica, dissolved and 

total-recoverable nutrients, dissolved iron and manganese) 

indicate medial values or concentrations. 

Drought samples from the Upper Colorado River Basin 

had water-quality exceedances for pH and concentrations of 

chloride, sulfate, nitrite nitrogen, dissolved iron, dissolved 

manganese, and dissolved selenium. pH exceeded the upper 

standard of 9.0 SU five times at four sites; the effect of the 

drought on these exceedances is unknown. The chloride 

standard of 250 mg/L was exceeded once at one site, and the 

26 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
exceedance was likely a result of the drought. The sulfate standard of 250 mg/L was exceeded five times at four sites, and 

three of the exceedances were likely an effect of the drought. 

Nitrite nitrogen exceeded the chronic standard of 0.05 mg/L 

twice at one site, and the exceedances were likely affected by 

drought. Dissolved iron exceeded the chronic standard of 300 

μg/L twice at one site and the exceedances were not affected 

by drought. Dissolved manganese exceeded the hardnessbased chronic standard of 50 μg/L three times at two sites; two 

exceedances at one site were affected by drought. Dissolved 

selenium exceeded the chronic standard of 4.6 μg/L four times 

at three sites; historical data indicate that these exceedances 

were not affected by drought.

Drought samples were collected at four sites in the Rio 

Grande Basin. Average percentiles for properties and constituents only indicate result for medial water temperature, but all 

other properties and constituents had too few percentiles for 

characterization. The only water-quality exceedance for this 

basin was for dissolved zinc in one sample at one site; it is 

unknown if this sample was affected by drought. 

Drought samples were collected at 21 sites in the Gunnison River Basin. Average percentiles for properties and 

constituents indicate elevated specific conductance and 

elevated concentrations of dissolved chloride, dissolved silica, 

and dissolved sulfate. All other constituents with sufficient 

data—including other field properties and most dissolved 

and total-recoverable nutrients—indicated medial values or 

concentrations. Drought samples collected in the basin had 

water-quality exceedances for sulfate (one sample, one site), 

E. coli bacteria (four samples, three sites), total-recoverable 

iron (two samples, two sites), dissolved manganese (one 

sample, one site), and dissolved selenium (three samples, two 

sites). The only exceedance that likely was affected by drought 

was dissolved manganese.

Drought samples were collected at five sites in the 

Dolores River Basin. Average percentiles indicate that specific 

conductance was elevated and that temperature was medial. 

pH, chloride, fluoride, silica, and sulfate had too few sites for 

basin characterization, although all had high average percentiles, indicating elevated levels. E. coli bacteria was the only 

constituent showing a water-quality exceedance (one sample, 

one site) and it is unknown if the exceedance was affected by 

drought. 

Drought samples were collected at 14 sites in the San 

Juan River Basin. Average percentiles indicate that specific 

conductance and concentrations of chloride, fluoride, and 

sulfate were elevated, whereas pH and temperature values 

and silica concentrations had medial values. Dissolved and 

total-recoverable nutrients had too few sites for characterization. Metals were sampled too infrequently to allow calculation of reliable percentiles. Drought samples had water-quality 

exceedances for sulfate (one sample, one site), E. coli bacteria 

(seven samples, five sites), and dissolved iron (one sample, 

one site). It is unknown if any of the exceedances were 

affected by drought.

Drought samples were collected at 23 sites in the South 

Platte River Basin. Average percentiles indicated medial 

values and concentrations for field properties, most dissolved 

and total-recoverable nutrients, dissolved organic carbon, and 

some dissolved trace metals (copper, iron, manganese, and 

silver). Too few sites had reliable percentiles to allow characterization of dissolved organic plus ammonia nitrogen, totalrecoverable organic carbon, total-recoverable iron, dissolved 

lead, and dissolved nickel.

Drought samples exceeded water-quality standards for 

pH (9.0 standard units; 3 samples, three sites), dissolved 

ammonia (10 samples, six sites), dissolved nitrite (1 sample, 

one site), dissolved copper (1 sample, one site), and dissolved 

manganese (2 samples, one site). Historical data indicate that 

the single nitrite exceedance likely was affected by drought.

Drought samples were collected at 23 sites in the 

Arkansas River Basin. Average percentiles indicate elevated 

specific conductance values and elevated sulfate concentration; 

concentrations of total-recoverable iron and manganese (tentative) were depressed. Dissolved oxygen, pH, most dissolved 

and total-recoverable nutrients, fecal-coliform bacteria, some 

dissolved metals (cadmium, iron, lead, manganese, and zinc), 

and some total-recoverable metals (cadmium, chromium, and 

zinc) indicated medial values and concentrations. Too few 

sites had reliable percentiles for total-recoverable organic plus 

ammonia nitrogen, some dissolved metals (arsenic, chromium, 

copper, nickel, selenium, and silver), and some total-recoverable metals (copper, mercury, and nickel). Drought samples 

indicate water-quality exceedances for sulfate (2 samples, 

2 sites), E. coli bacteria (20 samples, 16 sites), fecal-coliform bacteria (18 samples, 14 sites), total-recoverable iron 

(1 sample, 1 site), dissolved manganese (6 samples, 6 sites), 

and dissolved selenium (3 samples, 3 sites). Drought conditions probably caused exceedances of water-quality standards 

for sulfate at two sites, fecal coliform at one site, manganese at 

four sites, and selenium at two sites. 

Percentiles for all drought samples collected in Colorado 

during summer 2002 indicate that few measured constituents 

were elevated or depressed in concentration or value on a 

widespread basis. Specific conductance was elevated at five 

of the seven basins (or basin groups) that had sufficient data 

for characterization. Similarly, chloride concentrations were 

elevated in three of five basins with sufficient data, indicating 

that chloride concentration generally was affected by drought 

in those basins. Sulfate concentration was elevated in four 

of six basins with sufficient data. All basins that exhibited 

elevated concentrations of chloride and sulfate also exhibited 

elevated specific conductance. The widespread elevation of 

specific conductance and concentrations of chloride and sulfate indicates that salinity generally was affected by drought 

in Colorado streams during July through September 2002— 

undoubtedly because streamflow at most sites was dominated 

by base flow of ground water, which usually has considerable 

salinity compared to runoff from precipitation.

Fluoride showed elevated concentrations in two of four 

basins with sufficient data to characterize (Upper Colorado 

Summary 27
(tentative); San Juan). Both basins with elevated concentrations of fluoride exhibited elevated specific conductance and 

elevated concentrations of chloride and sulfate, which is consistent with a ground-water source for fluoride. Dissolved and 

total-recoverable nutrients (nitrogen and phosphorus) showed 

medial (and near-medial) concentrations in all basins with 

sufficient data to characterize. Dissolved and total-recoverable 

concentrations of metals were mostly medial and could for the 

most part only be characterized for individual basins. Percentiles for concentrations of total recoverable iron and total 

recoverable manganese in the Arkansas Basin were depressed. 

In total, 115 of the 246 water samples collected at 

148 sites in the summer of 2002 exceeded Colorado waterquality standards. Constituents that exceeded water-quality 

standards were pH (all exceeding 9.0; 9 samples), chloride 

(1 sample), sulfate (9 samples), dissolved ammonia (10 samples), dissolved nitrite nitrogen (3 samples), E. coli bacteria 

(34 samples, 20 in Arkansas River Basin), fecal-coliform 

bacteria (18 samples, all in Arkansas River Basin), dissolved 

copper (1 sample), dissolved iron (3 samples), total-recoverable iron (3 samples), dissolved manganese (13 samples), 

dissolved selenium (10 samples), and dissolved zinc (1 sample). For these 115 exceedances, historical data were sufficient to conclude that 21 probably were affected by drought, 

39 probably were not affected by drought, and 55 were of 

indeterminate nature. Overall, the data indicate that some 

water-quality exceedances probably would have occurred 

during July through September 2002 without drought but that 

drought probably affected concentrations of some constituents 

(especially dissolved manganese and sulfate) enough to locally 

cause exceedances of water-quality standards.

Specific-conductance values indicate the San Juan 

River Basin (average percentile 95.2) experienced the greatest effects of drought on water quality during summer 2002 

compared to other basins in Colorado, followed by the Upper 

Colorado (90.0) and Dolores River (85.7) Basins. The South 

Platte River Basin (70.9) experienced the least effect of 

drought, and the Yampa and White River Basin group (73.7) 

had the second smallest effect. The Gunnison River (82.1) and 

Arkansas River (81.2) Basins had intermediate drought effects. 

The Rio Grande Basin had insufficient data to rank the relative 

effect of drought on salinity.

References Cited

Chafin, D. T., 2002, Evaluation of trends in pH in the Yampa 

River, northwestern Colorado, 1950–2000: U.S. Geological 

Survey Water-Resources Investigations Report 2002–4038, 

41 p.

Colorado Department of Public Health and Environment, 

2005, Water quality regulations: Web site accessed October 

2005 at http://www.cdphe.state.co.us/regulations/wqccregs/

index.html

Crowfoot, R.M., Boulger, R.W., and O’Neill, G.B., 2003, 

Water resources data, Colorado, water year 2002—

Volume 2. Colorado River Basin: U.S. Geological Survey 

Water-Data Report CO–02–2, 623 p.

Crowfoot, R.M., Payne, W.F., and O’Neill, G.B., 2003, Water 

resources data, Colorado, water year 2002—Volume 1. 

Missouri River Basin, Arkansas River Basin, and Rio 

Grande Basin: U.S. Geological Survey Water-Data Report 

CO–02–1, 609 p.

Helsel, D. R., 1990, Less than obvious—Statistical treatment 

of data below the detection limit: Environmental Science 

and Technology, v. 24, no. 12, p. 1766–1774

Helsel, D.R., and Hirsch, R.M., 1992, Statistical methods in 

water resources: New York, Elsevier, 529 p. 

Kuhn, Gerhard, 2005, Historic perspective of statewide 

streamflows during the 2002 and 1977 droughts in Colorado: U.S. Geological Survey Scientific Investigations 

Report 2005–5174, 84 p.

Sprague, L.A., Kimbrough, R.A., and Ranalli, A.J., 2002, 

What happens to nutrients in offstream reservoirs in the 

lower South Platte River Basin?: U.S. Geological Survey 

Fact Sheet 044–02, 6 p.

U.S. Geological Survey, 1998, National field manual for the 

collection of water-quality data: U.S. Geological Survey 

Techniques of Water-Resources Investigations, book 9, 

chap. A4, variously paginated.

Winter, T.C., Harvey, J.W., Franke, O.L., and Alley., W.M., 

1999, Ground water and surface water—A single resource: 

U.S. Geological Survey Circular 1139, 79 p.

28  Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
Appendix

This appendix contains data tables in support of the findings for this study.
Conc Q% N Value Q% N

1 7-29-2002 1415 3.0 6.2 ID 5 7.5 ID 8

9-3-2002 1130 2.4 7.9 ID 5 7.6 ID 8

2 7-29-2002 1540 65.0 8.2 ID 9 9.3 ID 12

3 7-30-2002 850 54.0 8.3 ID 11 8.1 ID 11

9-3-2002 1400 8.3 7.8 ID 11 8.2 ID 11

4 7-30-2002 1100 1.9 7.3 ID 19 8.8 ID 19

5 7-30-2002 1520 57.0 9.8 1

66.7–71.4 20 8.8 173.9–91.3 22

6 7-30-2002 1400 20.0 6.9 1

14.3–19.0 20 8.4 159.1–63.6 21

9-3-2002 1655 2.9 7.6 42.9 20 8.0 9.1 21

7 7-31-2002 850 48.0 6.6 2.2 45 8.4 1

39.1–54.3 45

9-4-2002 910 4.0 8.4 60.9 45 8.2 1

15.2–28.3 45

8 7-31-2002 1020 70.0 7.0 ID 7 8.4 ID 8

9-4-2002 1130 4.2 8.6 ID 7 8.4 ID 8

9 7-29-2002 1230 140.0 8.2 1

26.1–30.4 22 8.6 96.0 24

9-9-2002 1400 119.0 8.1 1

17.4–21.7 22 8.5 176.0–92.0 24

10 7-29-2002 1425 119.0 8.2 1

45.5–50.0 21 8.6 172.0–84.0 24

9-9-2002 1555 122.0 8.2 1

45.5–50.0 21 8.6 172.0–84.0 24

11 7-30-2002 1250 24.0 7.3 13.0 22 8.6 1

82.5–92.2 102

9-10-2002 1035 12.0 8.2 1

43.5–47.8 22 8.3 133.0–49.5 102

12 7-30-2002 1505 205.0 7.7 5.6 35 8.6 1

83.3–92.2 101

9-10-2002 1400 180.0 7.9 1

13.9–16.7 35 8.4 159.8–74.5 101

13 9-11-2002 1155 8.6 9.0 1

54.3–56.5 45 8.3 138.8–71.4 48

14 7-31-2002 900 3.0 8.9 64.1 38 8.8 1

78.6–95.2 41

15 9-11-2002 1049 0.4 9.0 89.3 27 7.9 1

32.1–60.7 27

16 7-31-2002 1107 1.6 8.4 27.6 28 8.5 1

10.3–20.7 28

17 7-31-2002 1400 176.0 7.8 27.5 39 8.5 1

53.2–72.3 46

9-10-2002 1715 176.0 7.7 17.5 39 8.3 1

6.4–27.7 46

18 7-31-2002 1600 180.0 7.2 ID 16 8.5 ID 16

9-10-2002 1944 176.0 7.8 ID 16 8.4 ID 16

19 7-30-2002 1030 266.0 8.1 ID 9 8.6 ID 9

9-9-2002 1750 290.0 8.1 ID 9 8.6 ID 9

Yampa River Basin

White River Basin

Site number

in table 1

and fig. 4

Sampling

date

Sampling

time

Discharge,

in ft

3

/s

Oxygen, dissolved, in mg/L pH, in standard units

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of droughtsample constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25 ̊Celsius; 

 ̊C, degrees Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type 

indicate 2002 Colorado water-quality exceedances; c, chronic water-quality exceedance]

Table 11.  Water-quality data for the Yampa and White River Basins, showing 2002 drought values, Colorado water-quality

exceedances, and percentiles relative to historical data for selected properties and constituents from July through September,

1978–2002.

30 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
1 7-29-2002

9-3-2002

2 7-29-2002

3 7-30-2002

9-3-2002

4 7-30-2002

5 7-30-2002

6 7-30-2002

9-3-2002

7 7-31-2002

9-4-2002

8 7-31-2002

9-4-2002

9 7-29-2002

9-9-2002

10 7-29-2002

9-9-2002

11 7-30-2002

9-10-2002

12 7-30-2002

9-10-2002

13 9-11-2002

14 7-31-2002

15 9-11-2002

16 7-31-2002

17 7-31-2002

9-10-2002

18 7-31-2002

9-10-2002

19 7-30-2002

9-9-2002

Site number

in table 1

and fig. 4

Sampling

date

Value Q% N Value Q% N

25 1

30.8–41 38 16.5 89.5 37 9 2.7 0.5

24 28.2 38 11.5 1

23.7–26.3 37 8 2.5 0.5

199 31.3 63 24.0 1

96.8–98.4 62 86 22.7 7.2

147 90.7 42 16.0 1

46.5–53.5 42 64 19.2 4.0

229 97.7 42 16.6 55.8 42 98 28.3 6.6

343 57.9 26 22.5 59.3 27 130 30.7 12.5

373 1

60.2–61.2 102 25.0 96.1 102 120 29.7 11.4

684 1

83.2–85.1 100 24.0 190.3–94.2 102 240 48.9 29.0

1,040 99.0 100 19.9 1

62.1–63.1 102 240 44.1 32.1

866 93.9 65 18.5 1

25.6–31.1 89 250 49.0 30.2

1,350 98.5 65 13.9 6.7 89 350 78.9 37.0

956 93.9 48 22.5 1

63.5–65.4 51 260 59.9 27.3

972 98.0 48 16.1 1.9 51 290 62.6 31.8

374 96.0 74 16.5 90.8 75 190 59.9 10.7

397 98.7 74 15.5 1

85.5–86.8 75 -- -- --

336 1

96.9–98.4 63 17.3 87.5 63 180 52.5 10.8

287 50.0 63 16.8 84.4 63 -- -- --

570 98.6 145 22.5 98.6 143 290 87.9 16.4

576 99.3 145 15.1 1

61.8–62.5 143 -- -- --

785 94.8 133 22.7 98.6 138 380 102.0 31.9

891 99.3 133 19.2 1

82.7–83.5 138 420 107.0 37.5

1,620 39.4 65 13.7 18.6 85 480 62.1 77.7

4,330 94.4 70 15.0 1

17.8–23.8 100 400 13.6 88.9

1,390 22.4 48 12.2 1

13.7–15.1 72 550 100.0 71.2

3,720 80.0 54 21.5 1

70.6–71.8 84 690 22.7 152.0

843 90.0 79 23.7 93.9 130 350 83.7 35.2

1,030 98.8 79 21.7 74.0 130 -- -- --

930 ID 16 23.9 ID 16 350 77.8 36.9

966 ID 16 20.2 ID 16 -- -- --

418 ID 9 15.0 ID 9 220 66.8 12.0

400 ID 9 16.0 ID 9 -- -- --

Yampa River Basin—Continued

Hardness,

total,

in mg/L

as CaCO3

Magnesium,

dissolved,

in mg/L

Calcium,

dissolved,

in mg/L

Specific conductance, in μS/cm Temperature, water, in o

C

White River Basin—Continued

Table 11.  Water-quality data for the Yampa and White River Basins, showing 2002 drought values, Colorado water-quality

exceedances, and percentiles relative to historical data for selected properties and constituents from July through September,

1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of droughtsample constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25 ̊Celsius; 

 ̊C, degrees Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type 

indicate 2002 Colorado water-quality exceedances; c, chronic water-quality exceedance]

Appendix 31
1 7-29-2002

9-3-2002

2 7-29-2002

3 7-30-2002

9-3-2002

4 7-30-2002

5 7-30-2002

6 7-30-2002

9-3-2002

7 7-31-2002

9-4-2002

8 7-31-2002

9-4-2002

9 7-29-2002

9-9-2002

10 7-29-2002

9-9-2002

11 7-30-2002

9-10-2002

12 7-30-2002

9-10-2002

13 9-11-2002

14 7-31-2002

15 9-11-2002

16 7-31-2002

17 7-31-2002

9-10-2002

18 7-31-2002

9-10-2002

19 7-30-2002

9-9-2002

Site number

in table 1

and fig. 4

Sampling

date

Conc Q% N Conc Q% N

0.6 1.2 11 0.2 ID 8 -- -- --

0.6 1.2 10 0.3 ID 8 -- -- --

1.4 7.7 -- -- -- -- -- -- --

1.6 4.3 62 1.7 ID 11 -- -- --

1.8 7.5 85 3.9 ID 11 -- -- --

1.6 20.5 107 4.4 ID 19 0.2 ID 19

2.8 29.9 116 12.4 81.0 20 0.3 1

66.7–95.2 20

3.0 54.7 266 6.3 ID 18 -- -- --

3.7 146.0 417 11.6 ID 18 -- -- --

4.7 95.1 219 30.6 90.9 43 -- -- --

6.2 154.0 232 126.0 97.7 43 0.5 1

95.3–97.7 42

4.8 102.0 187 75.3 ID 9 0.4 ID 8

4.9 95.6 197 62.9 ID 9 -- -- --

1.0 2.8 98 0.4 ID 11 -- -- --

-- -- -- -- -- -- -- -- --

1.0 2.2 130 0.5 ID 10 -- -- --

-- -- -- -- -- -- -- -- --

1.7 11.3 197 5.8 95.8 94 -- -- --

-- -- -- -- -- -- -- -- --

2.0 28.1 231 10.7 38.9 94 0.3 1

61.5–92.3 25

2.8 38.8 245 13.0 1

48.4–49.5 94 0.4 96.2 25

2.7 194.0 471 16.9 45.0 39 0.7 1

25.0–40.0 39

5.1 989.0 1,970 169.0 91.7 35 3.4 94.4 35

1.8 109.0 398 12.7 46.4 27 0.3 28.6 27

3.8 746.0 1,290 109.0 48.3 28 1.9 55.2 28

2.4 49.0 217 14.7 76.7 29 -- -- --

-- -- -- -- -- -- -- -- --

2.8 74.2 237 22.7 ID 5 -- -- --

-- -- -- -- -- -- -- -- --

1.0 2.9 122 0.6 ID 1 -- -- --

-- -- -- -- -- -- -- -- --

Yampa River Basin—Continued

White River Basin—Continued

A Chloride, dissolved, in mg/L Fluoride, dissolved, in mg/L lkalinity,

laboratory,

in mg/L

as CaCO3

Sodium,

dissolved,

in mg/L

Potassium,

dissolved,

in mg/L

Table 11.  Water-quality data for the Yampa and White River Basins, showing 2002 drought values, Colorado water-quality

exceedances, and percentiles relative to historical data for selected properties and constituents from July through September,

1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of droughtsample constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25 ̊Celsius; 

 ̊C, degrees Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type 

indicate 2002 Colorado water-quality exceedances; c, chronic water-quality exceedance]

32 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
1 7-29-2002

9-3-2002

2 7-29-2002

3 7-30-2002

9-3-2002

4 7-30-2002

5 7-30-2002

6 7-30-2002

9-3-2002

7 7-31-2002

9-4-2002

8 7-31-2002

9-4-2002

9 7-29-2002

9-9-2002

10 7-29-2002

9-9-2002

11 7-30-2002

9-10-2002

12 7-30-2002

9-10-2002

13 9-11-2002

14 7-31-2002

15 9-11-2002

16 7-31-2002

17 7-31-2002

9-10-2002

18 7-31-2002

9-10-2002

19 7-30-2002

9-9-2002

Site number

in table 1

and fig. 4

Sampling

date

Conc Q% N Conc Q% N Conc Q% N

5.8 ID 8 1.5 ID 8 -- <0.015 ID 7

5.3 ID 8 1.3 ID 8 -- 0.01 ID 7

-- -- -- -- -- -- -- 0.01 ID 7

3.3 ID 11 10.1 ID 11 -- <0.015 ID 7

2.3 ID 11 24.0 ID 11 -- <0.015 ID 7

6.6 ID 19 61.3 ID 19 -- <0.04 ID 19

1.5 ID 19 51.6 57.1 20 -- <0.04 ID 8

14.4 ID 18 94.0 ID 18 -- <0.04 ID 11

12.9 ID 18 135.0 ID 18 -- 0.06 ID 11

5.8 72.7 43 195.0 93.2 43 565 <0.04 24.2–62.5 23

6.9 1

84.1–86.4 43 276.0 97.7 43 859 <0.04 24.2–62.5 23

13.3 ID 9 193.0 ID 9 -- <0.04 ID 7

11.4 ID 9 209.0 ID 9 -- <0.04 ID 7

18.4 ID 11 90.4 ID 11 -- <0.02 24.3–56.5 22

-- -- -- -- -- -- -- <0.02 24.3–56.5 22

14.9 ID 10 48.6 ID 10 -- <0.02 24.5–63.6 21

-- -- -- -- -- -- -- <0.02 24.5–63.6 21

17.3 ID 11 106.0 97.8 89 -- <0.04 24.5–90.9 21

-- -- -- -- -- -- -- <0.04 24.5–90.9 21

14.0 1

7.7–23.1 25 192.0 96.6 88 -- <0.04 24.0–80.0 24

16.6 80.8 25 224.0 98.9 88 -- <0.04 24.0–80.0 24

11.8 7.5 39 425.0 50.0 39 1,120 <0.04 23.2–74.2 30

-- -- -- 473.0 52.8 35 2,980 <0.04 24.2--70.8 23

21.2 1

37.0–40.7 26 363.0 21.4 27 -- <0.04 ID 17

7.9 1

31.0–34.5 28 839.0 62.1 28 -- <0.04 ID 19

10.5 6.9 28 220.0 86.7 29 -- <0.04 22.9–91.2 33

-- -- -- -- -- -- -- <0.04 22.9–91.2 33

9.9 ID 4 234.0 ID 5 -- 0.02 ID 16

-- -- -- -- -- -- -- <0.04 ID 16

16.3 ID 1 93.9 ID 1 -- <0.015 ID 9

-- -- -- -- -- -- -- <0.015 ID 9

Yampa River Basin—Continued

White River Basin—Continued

Silica, dissolved, in mg/L as SiO2

Nitrogen, ammonia, dissolved, in

mg/L as N

Solids, dissolved,

residue on

evaporation at

180 o

C, in mg/L

Sulfate, dissolved, in mg/L as SO4

Table 11.  Water-quality data for the Yampa and White River Basins, showing 2002 drought values, Colorado water-quality

exceedances, and percentiles relative to historical data for selected properties and constituents from July through September,

1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of droughtsample constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25 ̊Celsius; 

 ̊C, degrees Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, 

insufficient number of samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in 

bold type indicate 2002 Colorado water-quality exceedances; c, chronic water-quality exceedance]

Appendix 33
1 7-29-2002

9-3-2002

2 7-29-2002

3 7-30-2002

9-3-2002

4 7-30-2002

5 7-30-2002

6 7-30-2002

9-3-2002

7 7-31-2002

9-4-2002

8 7-31-2002

9-4-2002

9 7-29-2002

9-9-2002

10 7-29-2002

9-9-2002

11 7-30-2002

9-10-2002

12 7-30-2002

9-10-2002

13 9-11-2002

14 7-31-2002

15 9-11-2002

16 7-31-2002

17 7-31-2002

9-10-2002

18 7-31-2002

9-10-2002

19 7-30-2002

9-9-2002

Site number

in table 1

and fig. 4

Sampling

date

Conc Q% N Conc Q% N Conc Q% N

0.13 ID 7 -- -- -- 0.072 ID 7

0.23 ID 7 -- -- -- 0.090 ID 7

0.42 ID 7 0.73 ID 8 <0.013 ID 9

0.29 ID 7 -- -- -- <0.013 ID 7

0.23 ID 7 -- -- -- <0.013 ID 7

-- -- -- 0.55 ID 19 0.030 ID 19

-- -- -- 0.54 ID 16 <0.05 ID 8

0.33 ID 11 -- -- -- <0.05 ID 11

0.33 ID 11 -- -- -- <0.013 ID 11

0.46 ID 12 -- -- -- <0.1 2

3.8–92.3 25

-- -- -- 0.59 44.0 24 <0.1 2

3.8–92.3 25

-- -- -- 0.39 ID 6 <0.05 ID 9

0.28 ID 6 -- -- -- <0.05 ID 9

0.11 2

4.5–68.2 21 -- -- -- <0.1 24.3–91.3 22

-- -- -- 0.13 ID 16 <0.1 2

4.3–91.3 22

0.11 2

4.8–76.2 20 -- -- -- <0.1 24.5–90.9 21

-- -- -- 0.11 ID 16 <0.1 2

4.5–90.9 21

0.18 81.0 20 -- -- -- <0.1 2

4.5–90.9 21

-- -- -- 0.20 ID 17 <0.1 2

4.5–90.9 21

-- -- -- 0.46 1

70.0–73.3 29 <0.1 24.0–92.0 24

-- -- -- 0.52 83.3 29 <0.1 2

4.0–92.0 24

0.35 28.6 27 -- -- -- <0.1 2

2.5–42.5 39

0.69 61.9 20 -- -- -- <0.05 2

3.1–34.4 31

0.29 ID 17 -- -- -- 0.280 42.9 20

0.66 ID 19 -- -- -- <0.05 4.8 20

0.37 81.8 32 -- -- -- <0.05 2

3.3–56.7 29

-- -- -- 0.88 1

85.2–88.9 26 <0.05 23.3–56.7 29

0.46 ID 15 -- -- -- 0.030 ID 16

-- -- -- 0.53 ID 15 <0.05 ID 16

0.12 ID 8 -- -- -- <0.013 ID 9

-- -- -- 0.18 ID 8 <0.013 ID 9

Yampa River Basin—Continued

White River Basin—Continued

Nitrogen, nitrite plus nitrate, dissolved,

in mg/L as N

Nitrogen, organic plus ammonia,

total recoverable, in mg/L as N

Nitrogen, organic plus ammonia,

dissolved, in mg/L as N

Table 11.  Water-quality data for the Yampa and White River Basins, showing 2002 drought values, Colorado water-quality

exceedances, and percentiles relative to historical data for selected properties and constituents from July through September,

1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of droughtsample constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25 ̊Celsius; 

 ̊C, degrees Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, 

insufficient number of samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold 

type indicate 2002 Colorado water-quality exceedances; c, chronic water-quality exceedance]

34 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
1 7-29-2002

9-3-2002

2 7-29-2002

3 7-30-2002

9-3-2002

4 7-30-2002

5 7-30-2002

6 7-30-2002

9-3-2002

7 7-31-2002

9-4-2002

8 7-31-2002

9-4-2002

9 7-29-2002

9-9-2002

10 7-29-2002

9-9-2002

11 7-30-2002

9-10-2002

12 7-30-2002

9-10-2002

13 9-11-2002

14 7-31-2002

15 9-11-2002

16 7-31-2002

17 7-31-2002

9-10-2002

18 7-31-2002

9-10-2002

19 7-30-2002

9-9-2002

Site number

in table 1

and fig. 4

Sampling

date

Conc Q% N Conc Q% N Conc Q% N

<0.002 ID 7 0.002 ID 7 0.006 ID 2

<0.002 ID 7 0.005 ID 7 0.008 ID 2

0.002 ID 7 0.077 ID 7 0.121 ID 8

<0.002 ID 7 0.008 ID 7 0.019 ID 6

<0.002 ID 7 0.004 ID 7 0.009 ID 6

<0.008 ID 19 -- -- -- 0.032 ID 19

<0.008 ID 8 -- -- -- 0.063 ID 16

<0.008 ID 11 <0.06 ID 11 <0.06 ID 11

<0.002 ID 11 0.005 ID 11 0.033 ID 11

<0.008 ID 13 <0.06 2

3.6–89.3 27 0.040 157.7–61.5 25

<0.008 ID 13 -- -- -- 0.044 65.4 25

<0.008 ID 7 -- -- -- 0.035 ID 7

<0.008 ID 7 <0.06 ID 6 0.040 ID 7

<0.01 2

4.3–87.0 22 -- -- -- 0.022 ID 17

<0.01 2

4.3–87.0 22 0.017 63.6 21 0.023 ID 17

<0.01 2

4.5–90.9 21 0.013 81.0 20 0.016 ID 17

<0.01 2

4.5–90.9 21 -- -- -- 0.011 ID 17

<0.01 2

4.5–90.9 21 0.058 90.5 20 0.056 ID 18

<0.01 2

4.5–90.9 21 -- -- -- 0.024 ID 18

<0.01 2

4.2–91.7 23 -- -- -- 0.053 170.0–73.3 29

<0.01 2

4.2--91.7 23 -- -- -- 0.053 170.0–73.3 29

<0.008 67.7 30 0.030 50.0 27 0.060 ID 10

<0.02 2

4.2–79.2 23 <0.05 24.8–57.1 20 0.058 ID 10

0.005 ID 15 <0.06 ID 15 0.198 ID 2

<0.008 ID 15 <0.06 ID 16 0.024 ID 4

<0.01 2

2.9–85.3 33 <0.06 22.9–97.1 33 0.030 31.0 28

<0.01 2

2.9–85.3 33 -- -- -- 0.166 79.3 28

0.007 ID 16 <0.06 ID 15 <0.06 ID 16

<0.008 ID 16 -- -- -- 0.026 ID 16

<0.002 ID 9 0.014 ID 8 0.035 ID 9

<0.002 ID 9 -- -- -- 0.023 ID 9

Yampa River Basin—Continued

White River Basin—Continued

Nitrogen, nitrite, dissolved, in

mg/L as N

Phosphorus, total recoverable,

in mg/L as P Phosphorus, dissolved, in mg/L as P

Table 11.  Water-quality data for the Yampa and White River Basins, showing 2002 drought values, Colorado water-quality

exceedances, and percentiles relative to historical data for selected properties and constituents from July through September,

1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of droughtsample constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25 ̊Celsius; 

 ̊C, degrees Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, 

insufficient number of samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold 

type indicate 2002 Colorado water-quality exceedances; c, chronic water-quality exceedance]

Appendix 35
1 7-29-2002

9-3-2002

2 7-29-2002

3 7-30-2002

9-3-2002

4 7-30-2002

5 7-30-2002

6 7-30-2002

9-3-2002

7 7-31-2002

9-4-2002

8 7-31-2002

9-4-2002

9 7-29-2002

9-9-2002

10 7-29-2002

9-9-2002

11 7-30-2002

9-10-2002

12 7-30-2002

9-10-2002

13 9-11-2002

14 7-31-2002

15 9-11-2002

16 7-31-2002

17 7-31-2002

9-10-2002

18 7-31-2002

9-10-2002

19 7-30-2002

9-9-2002

Site number

in table 1

and fig. 4

Sampling

date

Conc Q% N Conc Q% N

<0.007 ID 7 -- -- -- -- 3 -- --

<0.007 ID 7 -- -- -- -- 3 -- --

0.056 ID 7 6.2 ID 2 -- 25 20 --

<0.007 ID 7 -- -- -- -- 14 -- --

<0.007 ID 7 -- -- -- -- 7 -- --

<0.02 ID 19 6.9 ID 10 7.4 14 21 <20

0.010 ID 8 5.5 ID 9 -- 28 52 --

<0.02 ID 11 -- -- -- -- 23 -- --

<0.007 ID 11 -- -- -- -- 12 -- --

<0.02 2

4.8–85.7 20 -- -- -- -- 40 -- --

<0.02 2

4.8–85.7 20 -- -- -- -- 28 -- --

<0.02 ID 7 4.4 ID 3 -- 40 93 --

<0.02 ID 7 5.7 ID 3 -- 18 -- <20

0.013 1

47.8–69.6 22 -- -- -- -- 25 -- --

0.01 1

34.8–43.5 22 -- -- -- -- 8 -- --

<0.01 2

4.5–63.6 21 -- -- -- -- 27 -- --

<0.01 2

4.5–63.6 21 -- -- -- -- 11 -- --

0.041 95.5 21 -- -- -- -- 32 -- --

0.01 1

45.5–68.2 21 -- -- -- -- 15 -- --

0.02 1

68.0–84.0 24 4.5 ID 13 -- 12 -- <20

0.03 88.0 24 6.6 ID 13 -- 24 -- <20

0.03 1

40.0–60.0 39 6.1 ID 11 -- 15 -- 2

0.02 1

24.2–39.4 32 10.1 ID 11 -- 15 -- 3

0.02 ID 16 7.0 60.0 24 -- 8 -- --

<0.02 ID 18 11.4 ID 19 -- 12 -- --

<0.02 2

2.9–91.2 33 -- -- -- -- 28 -- --

<0.02 2

2.9–91.2 33 -- -- -- -- 26 -- --

<0.02 ID 16 -- -- -- -- 18 -- --

<0.02 ID 16 -- -- -- -- 17 -- --

0.008 ID 9 -- -- -- -- 20 -- --

<0.007 ID 9 -- -- -- -- 18 -- --

Yampa River Basin—Continued

White River Basin—Continued

Carbon, organic, dissolved, in mg/L Phosphorus, orthophosphate,

dissolved, in mg/L as P Aluminum,

dissolved,

in μg/L

Bacteria, fecal

coliform, in

colonies per

100 mL

Bacteria,

E. coli ,

in colonies per

100 Ml

Carbon,

organic, total

recoverable,

in mg/L

Table 11.  Water-quality data for the Yampa and White River Basins, showing 2002 drought values, Colorado water-quality

exceedances, and percentiles relative to historical data for selected properties and constituents from July through September,

1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of droughtsample constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25 ̊Celsius; 

 ̊C, degrees Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, 

insufficient number of samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold 

type indicate 2002 Colorado water-quality exceedances; c, chronic water-quality exceedance]

36 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
1 7-29-2002

9-3-2002

2 7-29-2002

3 7-30-2002

9-3-2002

4 7-30-2002

5 7-30-2002

6 7-30-2002

9-3-2002

7 7-31-2002

9-4-2002

8 7-31-2002

9-4-2002

9 7-29-2002

9-9-2002

10 7-29-2002

9-9-2002

11 7-30-2002

9-10-2002

12 7-30-2002

9-10-2002

13 9-11-2002

14 7-31-2002

15 9-11-2002

16 7-31-2002

17 7-31-2002

9-10-2002

18 7-31-2002

9-10-2002

19 7-30-2002

9-9-2002

Site number

in table 1

and fig. 4

Sampling

date

Conc Q% N Conc Q% N

-- -- -- -- -- -- -- 74 ID 3 --

-- -- -- -- -- -- -- 221 ID 3 --

-- -- -- -- <0.1 -- 1.4 -- -- -- 370

-- -- -- -- -- -- -- 69 ID 3 --

-- -- -- -- -- -- -- 74 ID 3 --

-- -- -- -- <0.04 -- 1.7 14 ID -- --

-- -- -- -- <0.2 -- 0.6 -- -- -- 190

-- -- -- -- -- -- -- 10 ID 10 --

-- -- -- -- -- -- -- 8 ID 10 --

-- -- -- -- -- -- -- <10 2

4.5–27.3 21 --

-- -- -- -- -- -- -- -- -- -- --

-- -- -- -- <0.2 -- 0.7 -- -- -- 330

-- -- -- -- <0.04 -- 1.7 <10 ID 1 --

-- -- -- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- 6 ID 5 --

-- -- -- -- -- -- -- 9 ID 4 --

-- -- -- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- 18 ID 5 --

-- -- -- -- -- -- -- -- -- -- --

-- -- -- -- 0.20 -- 0.7 15 ID 17 --

-- -- -- -- <0.04 -- 1.8 23 ID 17 --

2 210 1

35–37.5 39 0.13 <0.8 2.6 14 50.0 23 --

7 700 83.3 35 0.05 <0.8 3.1 <30 2

4.3–60.9 22 --

-- 100 13.6–17.9 27 -- -- -- -- -- -- --

7 650 1

62.1–65.5 28 -- -- -- 11 ID 14 --

-- -- -- -- -- -- -- 17 70.8 23 --

-- -- -- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- <10 ID 3 --

-- -- -- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- 6 ID 1 --

-- -- -- -- -- -- -- -- -- -- --

Yampa River Basin—Continued

White River Basin—Continued

Arsenic,

dissolved,

in μg/L

Iron, total

recoverable,

in μg/L

Iron, dissolved, in μg/L Copper,

dissolved,

in μg/L

Chromium,

dissolved,

in μg/L

Cadmium,

dissolved,

in μg/L

Boron, dissolved, in μg/L

Table 11.  Water-quality data for the Yampa and White River Basins, showing 2002 drought values, Colorado water-quality

exceedances, and percentiles relative to historical data for selected properties and constituents from July through September,

1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of droughtsample constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25 ̊Celsius; 

 ̊C, degrees Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, 

insufficient number of samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold 

type indicate 2002 Colorado water-quality exceedances; c, chronic water-quality exceedance]

Appendix 37
1 7-29-2002

9-3-2002

2 7-29-2002

3 7-30-2002

9-3-2002

4 7-30-2002

5 7-30-2002

6 7-30-2002

9-3-2002

7 7-31-2002

9-4-2002

8 7-31-2002

9-4-2002

9 7-29-2002

9-9-2002

10 7-29-2002

9-9-2002

11 7-30-2002

9-10-2002

12 7-30-2002

9-10-2002

13 9-11-2002

14 7-31-2002

15 9-11-2002

16 7-31-2002

17 7-31-2002

9-10-2002

18 7-31-2002

9-10-2002

19 7-30-2002

9-9-2002

Site number

in table 1

and fig. 4

Sampling

date

Conc Q% N

-- -- -- -- -- -- -- --

-- -- -- -- -- -- -- --

<1 26.6 ID 9 88.1 <0.01 -- --

-- -- -- -- -- -- -- --

-- -- -- -- -- -- -- --

0.1 23.7 ID 7 -- -- -- --

<1 15.4 ID 15 71.3 <0.01 -- --

-- -- -- -- -- -- -- --

-- -- -- -- -- -- -- --

-- -- -- -- -- -- -- --

-- -- -- -- -- -- -- --

<1 4.6 ID 7 50.4 <0.01 -- --

<0.08 65c ID 7 -- -- -- --

-- -- -- -- -- -- -- --

-- -- -- -- -- -- -- --

-- -- -- -- -- -- -- --

-- -- -- -- -- -- -- --

-- -- -- -- -- -- -- --

-- -- -- -- -- -- -- --

<1 32.1 ID 10 -- -- -- --

0.1 21.9 ID 10 -- -- -- --

0.1 47.8 47.8 22 -- 0.01 7.6 5.2

<0.2 1.3 2

4.3–65.2 22 -- <0.06 10.3 1.2

-- -- -- -- -- -- -- --

-- 1.5 ID 14 -- -- 27.3 1.0

-- -- -- -- -- -- -- --

-- -- -- -- -- -- -- --

-- -- -- -- -- -- -- --

-- -- -- -- -- -- -- --

-- -- -- -- -- -- -- --

-- -- -- -- -- -- -- --

Yampa River Basin—Continued

White River Basin—Continued

Nickel,

dissolved,

in μg/L

Molybdenum,

dissolved,

in μg/L

Mercury,

dissolved,

in μg/L

Manganese,

total

recoverable,

in μg/L

Manganese, dissolved, in μg/L Lead,

dissolved,

in μg/L

Table 11.  Water-quality data for the Yampa and White River Basins, showing 2002 drought values, Colorado water-quality

exceedances, and percentiles relative to historical data for selected properties and constituents from July through September,

1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of droughtsample constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25 ̊Celsius; 

 ̊C, degrees Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, 

insufficient number of samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in 

bold type indicate 2002 Colorado water-quality exceedances; c, chronic water-quality exceedance]

38 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
1 7-29-2002

9-3-2002

2 7-29-2002

3 7-30-2002

9-3-2002

4 7-30-2002

5 7-30-2002

6 7-30-2002

9-3-2002

7 7-31-2002

9-4-2002

8 7-31-2002

9-4-2002

9 7-29-2002

9-9-2002

10 7-29-2002

9-9-2002

11 7-30-2002

9-10-2002

12 7-30-2002

9-10-2002

13 9-11-2002

14 7-31-2002

15 9-11-2002

16 7-31-2002

17 7-31-2002

9-10-2002

18 7-31-2002

9-10-2002

19 7-30-2002

9-9-2002

Site number

in table 1

and fig. 4

Sampling

date

Conc Q% N Conc Q% N

-- -- -- -- -- -- --

-- -- -- -- -- -- --

<2 ID 10 <0.1 <24 ID 9

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- <1 ID 5

<2 ID 17 <0.2 <24 ID 13

-- -- -- -- -- -- --

-- -- -- -- -- -- --

0.7 1

69.0–72.4 28 -- -- -- --

1.0 1

75.9–86.2 28 -- -- -- --

<2 ID 7 <0.2 <24 ID 7

-- -- -- -- 1.0 ID 7

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- <24 ID 6

-- -- -- -- 1.0 ID 6

<2 ID 14 <1 <20 2

4.2–83.3 23

<2 ID 17 <2 <20 2

4.3–69.6 22

-- -- -- -- -- -- --

-- -- -- -- <24 ID 14

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

Yampa River Basin—Continued

White River Basin—Continued

Zinc, dissolved, in μg/L Silver,

dissolved,

in μg/L

Selenium, dissolved, in μg/L

Table 11.  Water-quality data for the Yampa and White River Basins, showing 2002 drought values, Colorado water-quality

exceedances, and percentiles relative to historical data for selected properties and constituents from July through September,

1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of droughtsample constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25 ̊Celsius; 

 ̊C, degrees Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, 

insufficient number of samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in 

bold type indicate 2002 Colorado water-quality exceedances; c, chronic water-quality exceedance]

Appendix 39

1

 Possible percentile range because of uncensored ties in data.

2

 Possible percentile range because of censored or recensored ties in data.
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.

40 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002

Conc Q% N

20 8-1-2002 1300 40 9.0 ID 2

21 7-15-2002 1415 7.5 8.0 15.4 25

9-4-2002 1030 2.7 7.3 1

3.8–7.7 25

22 7-15-2002 1330 14 7.9 1

1.3–3.8 77

9-4-2002 1115 5.7 7.9 1

1.3–3.8 77

23 7-15-2002 1230 16 7.4 1

2.4–3.7 81

9-4-2002 1415 11 8.3 1

20.7–28.0 81

24 7-15-2002 1015 11 8.9 1

42.7–46.3 81

9-4-2002 1230 11 9.0 1

47.6–52.4 81

25 7-15-2002 1115 3.8 8.6 ID 15

9-4-2002 1315 3.7 10.4 ID 15

26 7-17-2002 1115 23 9.5 ID 10

9-6-2002 1130 17 10.8 ID 10

27 8-1-2002 1130 119 9.0 ID 9

28 8-8-2002 1315 234 6.6 ID 10

9-11-2002 1215 214 6.1 ID 10

29 8-8-2002 1215 9.1 9.9 ID 2

9-11-2002 1300 7.9 7.8 ID 2

30 7-29-2002 1200 3.0 8.5 1

84.8–89.1 45

9-10-2002 1300 0.8 6.4 4.3 45

31 7-29-2002 1330 21 8.9 1

60.0–64.0 24

9-10-2002 1130 223 8.6 48 24

32 8-8-2002 1100 257 10.0 ID 5

9-11-2002 1115 62 8.6 ID 5

33 7-30-2002 1115 919 7.0 1

13.0–17.4 22

34 7-30-2002 1035 8.7 7.2 ID 9

35 7-30-2002 1330 22 7.5 4.3 22

9-3-2002 1215 12 8.2 17.4 22

36 7-30-2002 1555 58 6.8 ID 18

9-3-2002 1620 32 7.7 ID 18

37 7-31-2002 1735 97 7.8 1

5.9–11.8 33

9-4-2002 1320 74 10.5 97.1 33

Oxygen, dissolved, in mg/L

Site number

in table 1

and fig. 4

Sampling date

Sampling

time

Discharge,

in ft

3

/s
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

Appendix 41

Conc Q% N

Oxygen, dissolved, in mg/L

Site number

in table 1

and fig. 4

Sampling date

Sampling

time

Discharge,

in ft

3

/s

38 8-1-2002 0900 982 7.4 ID 14

9-5-2002 1500 596 9.6 ID 14

39 8-1-2002 1130 1,040 7.1 9.1 32

9-6-2002 0910 746 8.4 1

54.5–63.6 32

40 7-29-2002 1350 24 8.2 ID 12

9-3-2002 1700 13 7.8 ID 12

41 7-29-2002 1610 237 8.1 ID 11

9-4-2002 0910 308 9.4 ID 11

42 7-30-2002 0905 70 8.7 ID 12

9-4-2002 1205 44 8.8 ID 12

43 7-30-2002 1035 45 9.4 ID 6

9-4-2002 1455 30 9.3 ID 6

44 7-30-2002 1320 392 11.0 ID 16

9-5-2002 0945 445 10.6 ID 16

45 7-31-2002 0915 1,460 8.0 ID 2

9-6-2002 1035 1,180 8.4 ID 2

46 8-2-2002 1340 <0.01 9.3 ID 16

47 8-1-2002 1300 1,440 7.2 1

2.4–4.9 40

9-3-2002 1030 1,270 7.9 1

34.1–41.5 40

48 8-1-2002 1000 8.7 7.4 7.7 25

9-5-2002 1030 16 7.8 30.8 25

49 7-31-2002 0930 75 7.1 ID 4

50 7-31-2002 1645 256 -- -- --

51 8-1-2002 1515 1,050 8.2 ID 1

52 8-1-2002 0910 1,280 6.6 1

1.9–5.6 53

9-17-2002 0940 2,520 7.4 1

35.2–46.3 53

53 7-31-2002 1145 216 10.2 ID 1

54 8-1-2002 1145 992 7.4 ID 1

55 7-30-2002 0840 1.4 7.5 ID 7

56 7-31-2002 1200 1,460 9.1 ID 2

9-5-2002 1325 1,190 9.5 ID 2

57 7-31-2002 1515 72 7.1 ID 8

9-4-2002 1015 57 10.4 ID 8

58 7-16-2002 1315 14 8.0 ID 6

9-5-2002 0915 9.4 8.5 ID 6
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

42 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002

20 8-1-2002

21 7-15-2002

9-4-2002

22 7-15-2002

9-4-2002

23 7-15-2002

9-4-2002

24 7-15-2002

9-4-2002

25 7-15-2002

9-4-2002

26 7-17-2002

9-6-2002

27 8-1-2002

28 8-8-2002

9-11-2002

29 8-8-2002

9-11-2002

30 7-29-2002

9-10-2002

31 7-29-2002

9-10-2002

32 8-8-2002

9-11-2002

33 7-30-2002

34 7-30-2002

35 7-30-2002

9-3-2002

36 7-30-2002

9-3-2002

37 7-31-2002

9-4-2002

Site number

in table 1

and fig. 4

Sampling date

Value Q% N Value Q% N

7.6 ID 2 61 ID 12

8.0 1

30.8–38.5 25 74 165.6–71.9 63

8.0 1

30.8–38.5 25 108 98.4 63

8.4 1

94.0–96.4 82 85 182.1–83.3 83

8.1 1

62.7–80.7 82 108 98.8 83

8.1 1

69.0–78.2 86 75 184.1–86.4 87

8.4 1

90.8–94.3 86 96 98.9 87

8.7 1

48.9–56.8 107 115 97.7 87

9.1 1

68.2–73.9 107 133 98.9 87

8.7 ID 15 160 96.2 25

9.2 ID 15 154 92.3 25

9.1 ID 10 132 ID 11

9.1 ID 10 143 ID 11

9.1 ID 7 120 1

23.6–27.3 54

7.5 ID 10 121 1

84.6–86.2 64

8.1 ID 10 133 98.5 64

8.3 ID 2 559 ID 2

8.5 ID 2 555 ID 2

8.4 1

40.4–66.0 46 664 77.1 47

8.1 1

6.4–14.9 46 589 166.7–68.8 47

8.3 1

56.0–76.0 24 719 92.0 24

8.0 1

12.0–16.0 24 722 96.0 24

8.4 ID 5 232 ID 5

8.5 ID 5 255 ID 5

8.4 1

91.7–95.8 23 220 156.9–58.8 50

8.5 ID 9 247 94.2 51

9.0 1

87.5–91.7 23 364 188.0–92.0 24

8.9 1

79.2–83.3 23 466 96.0 24

8.6 ID 18 297 92.1 37

8.6 ID 18 416 97.4 37

8.5 1

68.6–82.9 34 1,050 91.2 33

8.5 1

68.6–82.9 34 1,360 97.1 33

pH, in standard units Specific conductance, in μS/cm
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

Appendix 43

Site number

in table 1

and fig. 4

Sampling date

38 8-1-2002

9-5-2002

39 8-1-2002

9-6-2002

40 7-29-2002

9-3-2002

41 7-29-2002

9-4-2002

42 7-30-2002

9-4-2002

43 7-30-2002

9-4-2002

44 7-30-2002

9-5-2002

45 7-31-2002

9-6-2002

46 8-2-2002

47 8-1-2002

9-3-2002

48 8-1-2002

9-5-2002

49 7-31-2002

50 7-31-2002

51 8-1-2002

52 8-1-2002

9-17-2002

53 7-31-2002

54 8-1-2002

55 7-30-2002

56 7-31-2002

9-5-2002

57 7-31-2002

9-4-2002

58 7-16-2002

9-5-2002

Value Q% N Value Q% N

pH, in standard units Specific conductance, in μS/cm

8.3 1

75.0–80.0 39 420 147.7–50.5 110

8.6 97.5 39 621 99.1 110

8.5 1

81.0–90.5 41 618 62.8 42

8.4 1

59.5–78.6 41 932 97.7 42

7.9 ID 12 77 85.7 55

7.8 ID 12 90 94.6 55

8.3 ID 11 392 ID 16

8.1 ID 11 327 ID 16

7.8 ID 12 519 96.6 57

7.7 ID 12 655 98.3 57

8.4 ID 6 633 ID 10

8.4 ID 6 658 ID 10

8.6 93.0 42 702 91.4 115

8.5 1

83.7–90.7 42 653 81.0 115

8.2 ID 2 1,060 ID 2

8.3 ID 2 1,330 ID 2

9.0 ID 16 3,850 ID 16

8.5 1

64.8–80.3 70 1,100 95.5 178

8.4 1

47.9–63.4 70 1,210 198.3–98.9 178

8.6 1

46.4–75.0 27 769 86.6 66

8.6 1

46.4–75.0 27 774 188.1–89.6 66

8.5 ID 7 1,070 1

91.7–93.8 47

8.3 ID 4 1,470 94.7 18

8.4 ID 4 1,240 ID 7

8.3 1

51.6–67.2 63 1,400 185.7–87.1 69

8.2 1

26.6–50.0 63 1,600 197.1–98.6 69

8.2 ID 1 1,350 ID 14

8.3 ID 4 1,180 ID 7

8.2 ID 8 164 ID 8

8.5 ID 2 1,070 ID 2

8.5 ID 2 1,290 ID 2

8.8 ID 8 1,090 ID 8

8.6 ID 8 1,500 ID 8

8.4 ID 6 150 ID 6

8.1 ID 6 168 ID 6
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

44 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002

20 8-1-2002

21 7-15-2002

9-4-2002

22 7-15-2002

9-4-2002

23 7-15-2002

9-4-2002

24 7-15-2002

9-4-2002

25 7-15-2002

9-4-2002

26 7-17-2002

9-6-2002

27 8-1-2002

28 8-8-2002

9-11-2002

29 8-8-2002

9-11-2002

30 7-29-2002

9-10-2002

31 7-29-2002

9-10-2002

32 8-8-2002

9-11-2002

33 7-30-2002

34 7-30-2002

35 7-30-2002

9-3-2002

36 7-30-2002

9-3-2002

37 7-31-2002

9-4-2002

Site number

in table 1

and fig. 4

Sampling date

Value Q% N

14.5 ID 12 24 7.5 1.3

13.0 98.4 63 23 5.3 2.3

6.0 1

23.4–28.1 63 33 7.4 3.7

14.0 98.8 83 26 6.4 2.5

10.0 1

83.3–88.1 83 37 9.3 3.4

16.0 98.9 87 25 6.6 2.1

14.0 1

95.5–96.6 87 33 8.3 3.0

16.0 1

76.1–78.4 87 38 10.8 2.7

16.0 1

76.1–78.4 87 48 13.9 3.3

17.0 1

61.5–65.4 25 -- -- --

18.0 76.9 25 -- -- --

18.0 ID 11 52 16.0 2.9

15.0 ID 11 59 17.9 3.4

19.5 1

92.7–94.5 54 51 16.2 2.7

10.0 1

70.8–83.1 64 52 16.4 2.7

15.0 98.5 64 59 18.6 3.0

18.0 ID 2 190 63 7.5

16.0 ID 2 190 63 7.2

17.0 1

40.0–46.0 49 320 85 24.8

17.0 1

40.0–46.0 49 240 63 20.1

12.0 1

44.0–52.0 24 330 85 29.1

14.0 76.0 24 320 81 29.0

15.0 ID 5 98 31 5.0

17.0 ID 5 120 36 6.2

16.0 1

78.8–80.8 51 98 30 5.3

14.5 1

77.4–81.1 52 130 31 13.6

17.5 96.0 24 180 57 9.7

14.5 92.0 24 230 72 12.1

20.0 97.4 37 150 42 10.6

14.5 68.4 37 200 58 14.4

24.0 97.1 34 400 123 21.6

18.5 1

85.7–88.6 34 490 152 25.4

Temperature, water, in o

C

Hardness,

total, in mg/L

as CaCO3

Magnesium,

dissolved,

in mg/L

Calcium,

dissolved, in

mg/L
[ft3

/s, cubic feet per second; Conc, concentration; Q% percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

Appendix 45

Site number

in table 1

and fig. 4

Sampling date

38 8-1-2002

9-5-2002

39 8-1-2002

9-6-2002

40 7-29-2002

9-3-2002

41 7-29-2002

9-4-2002

42 7-30-2002

9-4-2002

43 7-30-2002

9-4-2002

44 7-30-2002

9-5-2002

45 7-31-2002

9-6-2002

46 8-2-2002

47 8-1-2002

9-3-2002

48 8-1-2002

9-5-2002

49 7-31-2002

50 7-31-2002

51 8-1-2002

52 8-1-2002

9-17-2002

53 7-31-2002

54 8-1-2002

55 7-30-2002

56 7-31-2002

9-5-2002

57 7-31-2002

9-4-2002

58 7-16-2002

9-5-2002

Value Q% N

Temperature, water, in o

C

Hardness,

total, in mg/L

as CaCO3

Magnesium,

dissolved,

in mg/L

Calcium,

dissolved, in

mg/L

18.0 1

80.2–87.4 110 150 45 8.5

18.0 1

80.2–87.4 110 230 67 16.0

20.5 97.7 42 160 49 9.3

18.0 1

58.1–62.8 42 250 71 16.7

14.7 96.5 56 30 9.5 1.6

11.6 1

63.2–64.9 56 -- -- --

17.0 ID 16 190 58 9.6

9.5 ID 16 -- -- --

13.1 1

49.2–50.8 58 220 75 8.6

13.8 1

54.2–55.9 58 -- -- --

14.5 ID 10 310 95 16.3

16.3 ID 10 -- -- --

18.5 95.8 117 270 83 15.0

12.0 1

16.9–20.3 117 -- -- --

18.6 ID 2 210 64 12.0

15.2 ID 2 270 79 16.5

24.3 ID 16 1,100 46 228.0

22.0 1

96.0–98.0 200 220 66 14.4

17.5 1

36.3–40.8 200 250 73 16.7

20.5 1

71.6–74.6 66 250 29 41.8

16.5 1

22.4–25.4 66 270 40 41.6

22.8 1

77.1–79.2 47 230 67 15.1

-- -- -- 430 116 34.9

24.3 ID 7 450 121 34.9

23.5 1

88.7–93.0 70 520 139 42.2

18.0 1

15.5–19.7 70 600 171 42.4

23.3 ID 14 380 106 27.4

23.1 ID 7 440 119 33.3

9.5 ID 8 88 21 8.8

20.2 ID 2 210 64 12.8

17.9 ID 2 260 77 16.7

23.0 ID 8 250 74 16.0

13.5 ID 8 320 93 20.1

21.0 ID 6 -- -- --

10.0 ID 6 -- -- --
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

46 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002

20 8-1-2002

21 7-15-2002

9-4-2002

22 7-15-2002

9-4-2002

23 7-15-2002

9-4-2002

24 7-15-2002

9-4-2002

25 7-15-2002

9-4-2002

26 7-17-2002

9-6-2002

27 8-1-2002

28 8-8-2002

9-11-2002

29 8-8-2002

9-11-2002

30 7-29-2002

9-10-2002

31 7-29-2002

9-10-2002

32 8-8-2002

9-11-2002

33 7-30-2002

34 7-30-2002

35 7-30-2002

9-3-2002

36 7-30-2002

9-3-2002

37 7-31-2002

9-4-2002

Site number

in table 1

and fig. 4

Sampling date

0.69 2.1 -- 26 --

-- -- -- -- --

-- -- -- -- --

-- -- -- -- --

-- -- -- -- --

-- -- -- -- --

-- -- -- -- --

-- -- -- -- --

-- -- -- -- --

-- -- -- -- --

-- -- -- -- --

1.4 6.1 -- 55 --

2.0 7.5 -- 61 --

1.1 5.5 58 -- --

-- 3.1 -- 57 --

1.7 3.3 -- 62 --

5.6 45 -- 229 --

5.5 45 -- 222 --

2.9 33 246 -- --

2.4 33 195 -- --

2.5 33 132 -- --

2.4 33 139 -- --

1.8 5.3 -- 73 --

1.9 6.3 -- 82 --

1.9 6.2 71 -- --

1.0 2.8 -- 130 107

1.5 8.8 -- 123 102

1.8 11.3 -- 141 122

1.1 5.1 -- 101 88

1.3 7.7 -- 120 99

3.9 84 -- 138 120

4.0 102 -- -- 148

Acidneutralizing

capacity,

in mg/L

as CaCO3

Potassium,

dissolved, in

mg/L

Sodium,

dissolved, in

mg/L

Alkalinity,

laboratory, in

mg/L as CaCO3

Alkalinity,

onsite, in

mg/L as

CaCO3
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

Appendix 47

Site number

in table 1

and fig. 4

Sampling date

38 8-1-2002

9-5-2002

39 8-1-2002

9-6-2002

40 7-29-2002

9-3-2002

41 7-29-2002

9-4-2002

42 7-30-2002

9-4-2002

43 7-30-2002

9-4-2002

44 7-30-2002

9-5-2002

45 7-31-2002

9-6-2002

46 8-2-2002

47 8-1-2002

9-3-2002

48 8-1-2002

9-5-2002

49 7-31-2002

50 7-31-2002

51 8-1-2002

52 8-1-2002

9-17-2002

53 7-31-2002

54 8-1-2002

55 7-30-2002

56 7-31-2002

9-5-2002

57 7-31-2002

9-4-2002

58 7-16-2002

9-5-2002

Acidneutralizing

capacity,

in mg/L

as CaCO3

Potassium,

dissolved, in

mg/L

Sodium,

dissolved, in

mg/L

Alkalinity,

laboratory, in

mg/L as CaCO3

Alkalinity,

onsite, in

mg/L as

CaCO3

2.2 25 -- 91 --

2.4 41 -- 114 --

2.5 63 -- 94 --

3.1 97 -- 121 --

0.37 1.8 -- 28 --

-- -- -- -- --

1.2 4.0 -- 109 --

-- -- -- -- --

1.5 16.4 -- 111 --

-- -- -- -- --

1.7 12.0 -- 197 --

-- -- -- -- --

1.7 40 -- 150 --

-- -- -- -- --

3.8 125 -- 120 --

4.1 160 -- 137 --

3.6 581 -- 326 274

4.1 131 -- 130 --

3.8 142 -- 133 --

7.6 81 -- 325 --

7.0 75 -- 320 --

4.0 125 -- 132 --

4.9 144 -- 135 --

4.1 95 -- 153 --

4.4 113 -- 161 138

5.3 132 -- 182 156

4.4 135 -- 160 --

3.8 84 -- 152 --

0.84 1.6 -- 86 --

3.8 125 -- 126 --

4.1 154 -- 138 --

3.9 123 -- 126 108

4.6 182 -- 141 136

-- -- -- -- --

-- -- -- -- --
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

48 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002

20 8-1-2002

21 7-15-2002

9-4-2002

22 7-15-2002

9-4-2002

23 7-15-2002

9-4-2002

24 7-15-2002

9-4-2002

25 7-15-2002

9-4-2002

26 7-17-2002

9-6-2002

27 8-1-2002

28 8-8-2002

9-11-2002

29 8-8-2002

9-11-2002

30 7-29-2002

9-10-2002

31 7-29-2002

9-10-2002

32 8-8-2002

9-11-2002

33 7-30-2002

34 7-30-2002

35 7-30-2002

9-3-2002

36 7-30-2002

9-3-2002

37 7-31-2002

9-4-2002

Site number

in table 1

and fig. 4

Sampling date

Conc Q% N Conc Q% N

0.47 ID 2 -- -- --

9.1 89.3 27 -- -- --

10.1 92.9 27 -- -- --

9.3 88.9 26 -- -- --

10.6 96.3 26 -- -- --

5.9 79.2 23 -- -- --

7.1 95.8 23 -- -- --

7.9 92.0 24 -- -- --

9.9 96.0 24 -- -- --

2.5 ID 15 -- -- --

2.0 ID 15 -- -- --

6.5 ID 10 0.22 ID 9

7.9 ID 10 0.3 ID 9

2.5 ID 7 0.18 ID 7

1.4 ID 6 -- -- --

1.3 ID 6 -- -- --

6.7 ID 2 -- -- --

6.9 ID 2 -- -- --

3.3 89.6 47 0.23 81.3 47

3.5 91.7 47 0.25 83.3 47

3.9 92.0 24 0.19 20.0 24

4.3 96.0 24 0.21 96.0 24

6.3 ID 2 -- -- --

6.4 ID 2 -- -- --

5.4 95.8 23 0.31 75.0 23

1.1 ID 6 0.1 ID 6

15.4 91.3 22 0.1 1

43.5–95.7 22

20 95.7 22 0.1 1

43.5–95.7 22

6.5 ID 12 0.1 ID 12

9.0 ID 12 0.1 ID 12

129 93.8 31 0.2 1

62.5–90.6 31

165 96.9 31 0.2 1

62.5–90.6 31

Chloride, dissolved, in mg/L Fluoride, dissolved, in mg/L
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

Appendix 49

Site number

in table 1

and fig. 4

Sampling date

38 8-1-2002

9-5-2002

39 8-1-2002

9-6-2002

40 7-29-2002

9-3-2002

41 7-29-2002

9-4-2002

42 7-30-2002

9-4-2002

43 7-30-2002

9-4-2002

44 7-30-2002

9-5-2002

45 7-31-2002

9-6-2002

46 8-2-2002

47 8-1-2002

9-3-2002

48 8-1-2002

9-5-2002

49 7-31-2002

50 7-31-2002

51 8-1-2002

52 8-1-2002

9-17-2002

53 7-31-2002

54 8-1-2002

55 7-30-2002

56 7-31-2002

9-5-2002

57 7-31-2002

9-4-2002

58 7-16-2002

9-5-2002

Conc Q% N Conc Q% N

Chloride, dissolved, in mg/L Fluoride, dissolved, in mg/L

33 90.1 80 -- -- --

46 98.8 80 -- -- --

91 92.7 40 -- -- --

135 97.6 40 -- -- --

0.53 ID 6 0.4 ID 6

-- -- -- -- -- --

3.5 ID 6 0.2 ID 6

-- -- -- -- -- --

7.4 ID 6 0.3 ID 6

-- -- -- -- -- --

4.5 ID 3 0.2 ID 3

-- -- -- -- -- --

55 92.0 74 0.2 ID 7

-- -- -- -- -- --

188 ID 2 -- -- --

237 ID 2 -- -- --

18.3 ID 16 0.3 ID 16

184 96.9 64 -- -- --

210 98.5 64 -- -- --

8.6 88.9 26 -- -- --

7.9 85.2 26 -- -- --

179 ID 9 -- -- --

179 ID 7 -- -- --

77 ID 7 -- -- --

98 1

87.3–88.9 62 -- -- --

112 96.8 62 -- -- --

182 ID 4 -- -- --

60 ID 7 -- -- --

0.41 ID 5 0.1 ID 5

188 ID 2 -- -- --

227 ID 2 -- -- --

198 ID 8 0.1 ID 8

292 ID 8 0.2 ID 8

5.8 ID 6 -- -- --

6.9 ID 6 -- -- --
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

50 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002

20 8-1-2002

21 7-15-2002

9-4-2002

22 7-15-2002

9-4-2002

23 7-15-2002

9-4-2002

24 7-15-2002

9-4-2002

25 7-15-2002

9-4-2002

26 7-17-2002

9-6-2002

27 8-1-2002

28 8-8-2002

9-11-2002

29 8-8-2002

9-11-2002

30 7-29-2002

9-10-2002

31 7-29-2002

9-10-2002

32 8-8-2002

9-11-2002

33 7-30-2002

34 7-30-2002

35 7-30-2002

9-3-2002

36 7-30-2002

9-3-2002

37 7-31-2002

9-4-2002

Site number

in table 1

and fig. 4

Sampling date

Conc Q% N Conc Q% N

4.5 33.3 2 3.2 66.7 2 --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

13.3 ID 9 2.3 ID 9 94

12.9 ID 9 2.8 ID 9 100

8.7 ID 7 3.0 ID 7 --

12.0 ID 6 5.5 ID 6 --

12.8 ID 6 5.9 ID 6 --

29 ID 2 69 ID 2 --

29 ID 2 70 ID 2 --

10.6 83.3 47 116 1

66.7–68.8 47 438

9.3 64.6 47 116 1

66.7–68.8 47 391

8.2 1

40.0–48.0 24 246 92.0 24 517

7.8 20.0 24 237 1

84.0–88.0 24 524

4.8 ID 2 35 ID 2 --

4.9 ID 2 39 ID 2 --

7.1 16.7 23 32 20.8 23 126

6.9 ID 6 11.2 ID 6 --

3.9 17.4 22 53 91.3 22 --

3.9 26.1 22 75 95.7 22 --

5.1 ID 12 48 ID 12 --

5.2 ID 12 83 ID 12 --

6.8 28.1 31 256 87.5 31 --

4.4 6.3 31 310 96.9 31 --

Silica, dissolved, in mg/L as SiO2 Sulfate, dissolved, in mg/L as SO4

Solids,

dissolved,

residue on

evaporation at

180

o

C,

in mg/L
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

Appendix 51

Site number

in table 1

and fig. 4

Sampling date

38 8-1-2002

9-5-2002

39 8-1-2002

9-6-2002

40 7-29-2002

9-3-2002

41 7-29-2002

9-4-2002

42 7-30-2002

9-4-2002

43 7-30-2002

9-4-2002

44 7-30-2002

9-5-2002

45 7-31-2002

9-6-2002

46 8-2-2002

47 8-1-2002

9-3-2002

48 8-1-2002

9-5-2002

49 7-31-2002

50 7-31-2002

51 8-1-2002

52 8-1-2002

9-17-2002

53 7-31-2002

54 8-1-2002

55 7-30-2002

56 7-31-2002

9-5-2002

57 7-31-2002

9-4-2002

58 7-16-2002

9-5-2002

Conc Q% N Conc Q% N

Silica, dissolved, in mg/L as SiO2 Sulfate, dissolved, in mg/L as SO4

Solids,

dissolved,

residue on

evaporation at

180

o

C,

in mg/L

6.1 ID 14 64 33.3 80 --

8.1 ID 14 132 98.8 80 --

6.3 2.4 40 68 24.4 40 358

7.8 31.7 40 137 97.6 40 549

5.2 ID 6 7.9 ID 6 --

-- -- -- -- -- -- --

7.6 ID 6 81 ID 6 --

-- -- -- -- -- -- --

8.5 ID 6 134 ID 6 --

-- -- -- -- -- -- --

12.9 ID 3 133 ID 3 --

-- -- -- -- -- -- --

10.3 ID 7 130 80.0 74 --

-- -- -- -- -- -- --

7.4 ID 2 99 ID 2 --

7.5 ID 2 143 ID 2 --

0.30 ID 16 1,910 ID 16 --

6.4 11.1 53 114 56.9 64 --

5.6 1.9 53 144 89.2 64 --

28 63.0 26 94 92.6 26 --

26 33.3 26 91 85.2 26 --

7.6 ID 9 121 ID 9 --

7.5 ID 7 338 ID 7 --

8.1 ID 7 388 ID 7 --

6.8 4.8 62 437 87.3 62 --

12.9 93.7 62 496 93.7 62 --

7.8 ID 4 259 ID 4 --

8.2 ID 7 370 ID 7 --

4.7 ID 5 5.9 ID 5 --

7.2 ID 2 103 ID 2 --

6.8 ID 2 140 ID 2 --

3.9 ID 8 113 ID 8 --

3.7 ID 8 165 ID 8 --

-- -- -- -- -- -- --

-- -- -- -- -- -- --
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

52 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002

20 8-1-2002

21 7-15-2002

9-4-2002

22 7-15-2002

9-4-2002

23 7-15-2002

9-4-2002

24 7-15-2002

9-4-2002

25 7-15-2002

9-4-2002

26 7-17-2002

9-6-2002

27 8-1-2002

28 8-8-2002

9-11-2002

29 8-8-2002

9-11-2002

30 7-29-2002

9-10-2002

31 7-29-2002

9-10-2002

32 8-8-2002

9-11-2002

33 7-30-2002

34 7-30-2002

35 7-30-2002

9-3-2002

36 7-30-2002

9-3-2002

37 7-31-2002

9-4-2002

Site number

in table 1

and fig. 4

Sampling date

Conc Q% N Conc Q% N

<0.007 ID 2 -- -- --

<0.002 2

4.2–54.2 23 -- -- --

<0.002 2

4.2–54.2 23 -- -- --

<0.002 2

3.3–56.7 29 -- -- --

<0.002 2

3.3–56.7 29 -- -- --

<0.015 2

2.9–88.2 33 -- -- --

<0.015 2

2.9–88.2 33 -- -- --

0.011 41.2 33 -- -- --

0.010 1

35.3–38.2 33 -- -- --

<0.015 ID 15 -- -- --

<0.015 ID 15 -- -- --

0.008 ID 10 0.30 ID 9

<0.015 ID 10 0.28 ID 9

<0.04 ID 8 0.26 ID 8

<0.015 ID 5 0.15 ID 5

0.010 ID 5 0.16 ID 5

<0.015 ID 2 0.34 ID 2

<0.015 ID 2 0.30 ID 2

<0.02 2

2.6–56.4 38 0.53 92.3 38

<0.02 2

2.6–56.4 38 0.37 161.5–64.1 38

0.028 66.7 23 0.33 1

70.8–79.2 23

0.081 87.5 23 0.41 87.5 23

<0.015 ID 2 0.12 ID 2

0.014 ID 2 0.18 ID 2

<0.015 2

4.3–39.1 22 -- -- --

<0.015 ID 9 0.07 ID 9

0.025 86.4 21 0.19 2

4.3–91.3 22

0.010 40.9 21 0.17 2

4.3–91.3 22

0.009 ID 18 0.12 ID 18

0.009 ID 18 0.12 ID 18

0.050 1

85.7–90.5 20 0.22 64.5 30

<0.02 2

4.8–28.6 20 0.21 61.3 30

Nitrogen, ammonia, dissolved, in

mg/L as N

Nitrogen, organic plus ammonia,

dissolved,

in mg/L as N
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

Appendix 53

Site number

in table 1

and fig. 4

Sampling date

38 8-1-2002

9-5-2002

39 8-1-2002

9-6-2002

40 7-29-2002

9-3-2002

41 7-29-2002

9-4-2002

42 7-30-2002

9-4-2002

43 7-30-2002

9-4-2002

44 7-30-2002

9-5-2002

45 7-31-2002

9-6-2002

46 8-2-2002

47 8-1-2002

9-3-2002

48 8-1-2002

9-5-2002

49 7-31-2002

50 7-31-2002

51 8-1-2002

52 8-1-2002

9-17-2002

53 7-31-2002

54 8-1-2002

55 7-30-2002

56 7-31-2002

9-5-2002

57 7-31-2002

9-4-2002

58 7-16-2002

9-5-2002

Conc Q% N Conc Q% N

Nitrogen, ammonia, dissolved, in

mg/L as N

Nitrogen, organic plus ammonia,

dissolved,

in mg/L as N

<0.015 ID 12 0.18 ID 12

<0.015 ID 12 0.20 ID 12

0.013 ID 2 0.16 ID 2

<0.015 ID 2 0.20 ID 2

<0.015 ID 12 0.05 ID 12

<0.015 ID 12 0.09 ID 12

0.016 ID 11 0.13 ID 11

<0.015 ID 11 0.11 ID 11

0.017 ID 12 <0.1 ID 12

0.008 ID 12 0.05 ID 12

0.034 ID 6 0.09 ID 6

0.013 ID 6 0.12 ID 6

0.021 ID 13 0.11 ID 13

<0.015 ID 13 0.12 ID 13

<0.015 ID 2 0.15 ID 2

<0.015 ID 2 0.20 ID 2

<0.04 ID 16 -- -- --

<0.04 ID 17 0.15 ID 17

<0.04 ID 17 0.16 ID 17

<0.04 ID 3 0.43 ID 2

<0.04 ID 3 0.36 ID 2

0.023 ID 1 0.18 ID 1

0.035 ID 1 0.26 ID 1

0.061 ID 1 0.35 ID 1

<0.04 1

2.1–64.6 47 0.29 67.7 30

<0.04 1

2.1–64.6 47 0.33 80.6 30

0.092 ID 1 0.29 ID 1

0.042 ID 1 0.27 ID 1

<0.015 ID 8 0.08 ID 8

<0.04 ID 2 0.15 ID 2

0.030 ID 2 0.18 ID 2

0.026 ID 8 0.26 ID 8

0.014 ID 8 0.27 ID 8

0.014 ID 6 -- -- --

<0.015 ID 6 -- -- --
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

54 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002

20 8-1-2002

21 7-15-2002

9-4-2002

22 7-15-2002

9-4-2002

23 7-15-2002

9-4-2002

24 7-15-2002

9-4-2002

25 7-15-2002

9-4-2002

26 7-17-2002

9-6-2002

27 8-1-2002

28 8-8-2002

9-11-2002

29 8-8-2002

9-11-2002

30 7-29-2002

9-10-2002

31 7-29-2002

9-10-2002

32 8-8-2002

9-11-2002

33 7-30-2002

34 7-30-2002

35 7-30-2002

9-3-2002

36 7-30-2002

9-3-2002

37 7-31-2002

9-4-2002

Site number

in table 1

and fig. 4

Sampling date

Conc Q% N Conc Q% N

0.22 ID 2 -- -- --

-- -- -- 0.055 58.3 23

-- -- -- 0.087 87.5 23

-- -- -- 0.040 43.3 29

-- -- -- 0.030 30.0 29

-- -- -- 0.078 1

61.8–64.7 33

-- -- -- 0.039 29.4 33

-- -- -- 0.312 97.1 33

-- -- -- 0.108 76.5 33

-- -- -- <0.013 ID 15

-- -- -- <0.013 ID 15

0.42 ID 9 0.147 ID 10

0.35 ID 9 0.165 ID 10

0.42 ID 8 <0.05 ID 8

-- -- -- 0.126 ID 5

-- -- -- 0.046 ID 5

-- -- -- <0.013 ID 2

-- -- -- <0.013 ID 2

0.69 91.5 46 <0.013 2

2.6–86.8 37

0.43 63.8 46 <0.013 2

2.6–86.8 37

0.40 76.0 24 0.206 54.2 23

0.49 84.0 24 0.081 25.0 23

-- -- -- 0.150 ID 2

-- -- -- 0.059 ID 2

0.22 1

50.0–58.3 23 0.107 62.5 23

0.06 ID 9 0.012 ID 9

0.42 95.7 22 0.771 91.3 22

0.27 91.3 22 1.12 95.7 22

0.17 ID 15 0.288 ID 18

0.15 ID 15 0.342 ID 18

0.37 74.2 30 0.276 57.1 34

0.26 1

61.3–64.5 30 0.236 42.9 34

Nitrogen, organic plus ammonia,

total recoverable,

in mg/L as N

Nitrogen, nitrite plus nitrate,

dissolved, in mg/L as N
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

Appendix 55

Site number

in table 1

and fig. 4

Sampling date

38 8-1-2002

9-5-2002

39 8-1-2002

9-6-2002

40 7-29-2002

9-3-2002

41 7-29-2002

9-4-2002

42 7-30-2002

9-4-2002

43 7-30-2002

9-4-2002

44 7-30-2002

9-5-2002

45 7-31-2002

9-6-2002

46 8-2-2002

47 8-1-2002

9-3-2002

48 8-1-2002

9-5-2002

49 7-31-2002

50 7-31-2002

51 8-1-2002

52 8-1-2002

9-17-2002

53 7-31-2002

54 8-1-2002

55 7-30-2002

56 7-31-2002

9-5-2002

57 7-31-2002

9-4-2002

58 7-16-2002

9-5-2002

Conc Q% N Conc Q% N

Nitrogen, organic plus ammonia,

total recoverable,

in mg/L as N

Nitrogen, nitrite plus nitrate,

dissolved, in mg/L as N

-- -- -- 0.016 ID 14

-- -- -- <0.013 ID 14

-- -- -- 0.026 ID 11

-- -- -- 0.030 ID 11

0.06 ID 12 0.012 ID 12

0.05 ID 12 0.010 ID 12

0.17 ID 11 0.103 ID 11

0.13 ID 11 0.091 ID 11

0.05 ID 12 0.031 ID 12

0.06 ID 12 0.026 ID 12

0.11 ID 6 0.245 ID 6

0.13 ID 6 0.200 ID 6

0.18 ID 13 0.042 ID 13

0.16 ID 13 0.047 ID 13

-- -- -- 0.031 ID 2

-- -- -- <0.013 ID 2

0.65 ID 16 <0.05 ID 16

-- -- -- <0.05 2

3.8–50 25

-- -- -- <0.05 2

3.8–50 25

-- -- -- <0.05 ID 6

-- -- -- <0.05 ID 6

-- -- -- 0.023 ID 1

-- -- -- 0.204 ID 1

-- -- -- 0.974 ID 1

-- -- -- 0.870 50.9 54

-- -- -- 1.31 92.7 54

-- -- -- 0.301 ID 1

-- -- -- 0.752 ID 1

0.08 ID 8 0.037 ID 8

-- -- -- <0.05 ID 2

-- -- -- <0.05 ID 2

0.40 ID 8 0.894 ID 8

0.34 ID 8 1.11 ID 8

-- -- -- 0.009 ID 6

-- -- -- <0.013 ID 6
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

56 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002

20 8-1-2002

21 7-15-2002

9-4-2002

22 7-15-2002

9-4-2002

23 7-15-2002

9-4-2002

24 7-15-2002

9-4-2002

25 7-15-2002

9-4-2002

26 7-17-2002

9-6-2002

27 8-1-2002

28 8-8-2002

9-11-2002

29 8-8-2002

9-11-2002

30 7-29-2002

9-10-2002

31 7-29-2002

9-10-2002

32 8-8-2002

9-11-2002

33 7-30-2002

34 7-30-2002

35 7-30-2002

9-3-2002

36 7-30-2002

9-3-2002

37 7-31-2002

9-4-2002

Site number

in table 1

and fig. 4

Sampling date

Conc Q% N Conc Q% N

-- -- -- -- -- --

<0.002 2

4.2–83.3 23 0.003 14.0–96.0 24

<0.002 2

4.2–83.3 23 <0.004 14.0–96.0 24

<0.002 2

3.3–83.3 29 0.004 161.9–81.0 20

<0.002 2

3.3–83.3 29 0.003 24.8–57.1 20

0.002 1

45.5–69.7 32 0.031 96.0 24

<0.002 2

3–42.4 32 0.022 92.0 24

0.021 97.1 33 0.113 92.0 24

0.006 1

44.1–50 33 0.123 96.0 24

<0.002 ID 15 0.022 ID 15

<0.002 ID 15 0.021 ID 15

0.005 ID 10 0.082 ID 10

0.004 ID 10 0.08 ID 10

<0.008 ID 8 0.03 ID 8

<0.002 ID 2 0.016 ID 5

0.003 ID 2 0.01 ID 5

<0.002 ID 2 0.099 ID 2

<0.002 ID 2 0.099 ID 2

<0.002 2

2.6–94.9 38 0.008 22.6–97.4 38

<0.002 2

2.6–94.9 38 0.006 22.6–97.4 38

0.004 2

4.2–87.5 23 0.004 129.2–79.2 23

0.004 2

4.2–87.5 23 0.009 129.2–79.2 23

0.003 ID 2 0.004 ID 2

0.003 ID 2 0.004 ID 2

0.002 2

4.2–87.5 23 0.007 4.3 22

<0.002 ID 9 0.003 ID 9

0.016 95.7 22 0.174 91.3 22

0.014 91.3 22 0.25 95.7 22

0.005 ID 18 0.038 ID 18

0.004 ID 18 0.047 ID 18

0.009 2

4.8–71.4 20 0.028 48.5 32

0.008 2

4.8–71.4 20 0.01 115.2–24.2 32

Nitrogen, nitrite, dissolved,

in mg/L as N

Phosphorus, dissolved,

in mg/L as P
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

Appendix 57

Site number

in table 1

and fig. 4

Sampling date

38 8-1-2002

9-5-2002

39 8-1-2002

9-6-2002

40 7-29-2002

9-3-2002

41 7-29-2002

9-4-2002

42 7-30-2002

9-4-2002

43 7-30-2002

9-4-2002

44 7-30-2002

9-5-2002

45 7-31-2002

9-6-2002

46 8-2-2002

47 8-1-2002

9-3-2002

48 8-1-2002

9-5-2002

49 7-31-2002

50 7-31-2002

51 8-1-2002

52 8-1-2002

9-17-2002

53 7-31-2002

54 8-1-2002

55 7-30-2002

56 7-31-2002

9-5-2002

57 7-31-2002

9-4-2002

58 7-16-2002

9-5-2002

Conc Q% N Conc Q% N

Nitrogen, nitrite, dissolved,

in mg/L as N

Phosphorus, dissolved,

in mg/L as P

<0.002 ID 12 0.007 ID 13

<0.002 ID 12 0.004 ID 13

0.002 ID 2 0.009 ID 2

<0.002 ID 2 0.004 ID 2

<0.002 ID 12 <0.004 ID 12

<0.002 ID 12 <0.004 ID 12

0.002 ID 11 0.017 ID 11

0.002 ID 11 0.01 ID 11

<0.002 ID 12 <0.004 ID 12

<0.002 ID 12 <0.004 ID 12

0.003 ID 6 0.004 ID 6

0.004 ID 6 0.002 ID 6

0.002 ID 13 0.008 ID 13

0.002 ID 13 0.003 ID 13

0.002 ID 2 0.009 ID 2

<0.002 ID 2 0.005 ID 2

<0.008 ID 16 -- -- --

<0.008 ID 17 <0.06 ID 19

<0.008 ID 17 <0.06 ID 19

<0.008 ID 3 <0.06 ID 3

<0.008 ID 3 <0.06 ID 3

0.004 ID 1 0.02 ID 1

0.007 ID 1 0.009 ID 1

0.022 ID 1 0.034 ID 1

0.012 51.4 36 <0.06 2

2.1–89.6 47

0.014 62.2 36 <0.06 2

2.1–89.6 47

0.005 ID 1 0.025 ID 1

0.008 ID 1 0.007 ID 1

<0.002 ID 8 0.003 ID 8

<0.008 ID 2 <0.06 ID 2

<0.008 ID 2 <0.06 ID 2

0.081 ID 8 0.115 ID 8

0.117 ID 8 0.15 ID 8

<0.002 ID 6 0.035 ID 6

<0.002 ID 6 0.029 ID 6
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

58 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002

20 8-1-2002

21 7-15-2002

9-4-2002

22 7-15-2002

9-4-2002

23 7-15-2002

9-4-2002

24 7-15-2002

9-4-2002

25 7-15-2002

9-4-2002

26 7-17-2002

9-6-2002

27 8-1-2002

28 8-8-2002

9-11-2002

29 8-8-2002

9-11-2002

30 7-29-2002

9-10-2002

31 7-29-2002

9-10-2002

32 8-8-2002

9-11-2002

33 7-30-2002

34 7-30-2002

35 7-30-2002

9-3-2002

36 7-30-2002

9-3-2002

37 7-31-2002

9-4-2002

Site number

in table 1

and fig. 4

Sampling date

Conc Q% N Conc Q% N

0.013 ID 2 <0.007 ID 2

0.005 ID 12 <0.007 2

4.0–96.0 24

0.004 ID 12 <0.007 2

4.0–96.0 24

0.011 ID 11 <0.007 2

4.3–91.3 22

0.01 ID 11 <0.007 2

4.3–91.3 22

0.046 ID 12 0.024 96.0 24

0.042 ID 12 0.015 88.0 24

0.175 ID 12 0.094 92.0 24

0.159 ID 12 0.101 96.0 24

0.036 ID 9 0.014 ID 15

0.032 ID 9 0.012 ID 15

0.118 ID 10 0.06 ID 10

0.114 ID 10 0.063 ID 10

0.05 ID 8 0.03 ID 8

0.024 ID 6 0.011 ID 5

0.021 ID 6 0.005 ID 5

0.114 ID 2 0.079 ID 2

0.113 ID 2 0.083 ID 2

0.026 76.2 41 <0.007 2

2.6–76.9 38

0.018 59.5 41 <0.007 2

2.6–76.9 38

0.015 2

4.0–88.0 24 <0.007 24.2–45.8 23

0.03 2

4.0–88.0 24 0.004 24.2–45.8 23

0.013 ID 2 <0.007 ID 2

0.008 ID 2 <0.007 ID 2

0.021 62.5 23 <0.007 4.2 23

0.006 ID 9 <0.007 ID 9

0.18 91.3 22 0.148 91.3 22

0.25 95.7 22 0.218 95.7 22

0.046 ID 15 0.029 ID 18

0.055 ID 15 0.038 ID 18

0.068 83.9 30 0.017 27.3 21

0.022 19.4 30 <0.007 4.5 21

Phosphorus, total recoverable, in

mg/L as P

Phosphorus, orthophosphate,

dissolved, in mg/L as P
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

Appendix 59

Site number

in table 1

and fig. 4

Sampling date

38 8-1-2002

9-5-2002

39 8-1-2002

9-6-2002

40 7-29-2002

9-3-2002

41 7-29-2002

9-4-2002

42 7-30-2002

9-4-2002

43 7-30-2002

9-4-2002

44 7-30-2002

9-5-2002

45 7-31-2002

9-6-2002

46 8-2-2002

47 8-1-2002

9-3-2002

48 8-1-2002

9-5-2002

49 7-31-2002

50 7-31-2002

51 8-1-2002

52 8-1-2002

9-17-2002

53 7-31-2002

54 8-1-2002

55 7-30-2002

56 7-31-2002

9-5-2002

57 7-31-2002

9-4-2002

58 7-16-2002

9-5-2002

Conc Q% N Conc Q% N

Phosphorus, total recoverable, in

mg/L as P

Phosphorus, orthophosphate,

dissolved, in mg/L as P

0.029 ID 12 <0.007 ID 13

0.018 ID 12 <0.007 ID 13

0.048 ID 2 <0.007 ID 2

0.029 ID 2 <0.007 ID 2

0.003 ID 12 <0.007 ID 12

<0.004 ID 12 <0.007 ID 12

0.023 ID 11 0.012 ID 11

0.021 ID 11 0.006 ID 11

0.004 ID 12 <0.007 ID 12

0.002 ID 12 <0.007 ID 12

0.008 ID 6 <0.007 ID 6

0.005 ID 6 <0.007 ID 6

0.014 ID 13 <0.007 ID 13

0.012 ID 13 <0.007 ID 13

0.043 ID 2 <0.007 ID 2

0.021 ID 2 <0.007 ID 2

0.023 ID 16 <0.02 ID 16

0.06 ID 13 <0.02 ID 19

0.04 ID 13 <0.02 ID 19

<0.06 ID 2 <0.02 ID 4

<0.06 ID 2 <0.02 ID 4

0.083 ID 1 0.012 ID 1

0.042 ID 1 <0.007 ID 1

0.094 ID 1 0.023 ID 1

0.11 1

32.6–39.1 45 0.01 22.3–58.1 42

1.95 97.8 45 <0.02 2

2.3–58.1 42

0.07 ID 1 0.015 ID 1

0.051 ID 1 <0.007 ID 1

0.006 ID 8 <0.007 ID 8

0.03 ID 2 <0.02 ID 2

<0.06 ID 2 <0.02 ID 2

0.147 ID 8 0.094 ID 8

0.164 ID 8 0.124 ID 8

0.058 ID 6 0.024 ID 6

0.045 ID 6 0.016 ID 6
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

60 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002

20 8-1-2002

21 7-15-2002

9-4-2002

22 7-15-2002

9-4-2002

23 7-15-2002

9-4-2002

24 7-15-2002

9-4-2002

25 7-15-2002

9-4-2002

26 7-17-2002

9-6-2002

27 8-1-2002

28 8-8-2002

9-11-2002

29 8-8-2002

9-11-2002

30 7-29-2002

9-10-2002

31 7-29-2002

9-10-2002

32 8-8-2002

9-11-2002

33 7-30-2002

34 7-30-2002

35 7-30-2002

9-3-2002

36 7-30-2002

9-3-2002

37 7-31-2002

9-4-2002

Site number

in table 1

and fig. 4

Sampling date

Conc Q% N

2.6 ID 2 -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- 12 -- --

-- -- -- 1 -- --

4.2 ID 9 30 -- --

4.3 ID 9 15 -- --

-- -- -- -- -- --

2.6 ID 3 2 -- <20

2.6 ID 3 1 -- <20

-- -- -- 4 -- --

-- -- -- 33 -- --

8.9 1

90.9–95.5 21 20 -- --

-- -- -- 3 -- --

6.7 ID 16 1 -- --

-- -- -- 1 -- --

2 ID 2 1 -- <20

2.1 ID 2 4 -- <20

-- -- -- 19 -- --

1.5 ID 3 2 2 --

1.7 ID 17 <1 3 --

-- -- -- 2 -- --

1.7 ID 4 9 12 --

-- -- -- 14 -- --

1.8 ID 5 10 11 --

2.3 ID 5 9 -- <20

Carbon, organic, dissolved,

in mg/L Bacteria,

E. coli ,

in colonies

per 100 mL

Bacteria,

fecal

coliform, in

colonies per

100 mL

Aluminum,

dissolved,

in μg/L
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

Appendix 61

Site number

in table 1

and fig. 4

Sampling date

38 8-1-2002

9-5-2002

39 8-1-2002

9-6-2002

40 7-29-2002

9-3-2002

41 7-29-2002

9-4-2002

42 7-30-2002

9-4-2002

43 7-30-2002

9-4-2002

44 7-30-2002

9-5-2002

45 7-31-2002

9-6-2002

46 8-2-2002

47 8-1-2002

9-3-2002

48 8-1-2002

9-5-2002

49 7-31-2002

50 7-31-2002

51 8-1-2002

52 8-1-2002

9-17-2002

53 7-31-2002

54 8-1-2002

55 7-30-2002

56 7-31-2002

9-5-2002

57 7-31-2002

9-4-2002

58 7-16-2002

9-5-2002

Conc Q% N

Carbon, organic, dissolved,

in mg/L Bacteria,

E. coli ,

in colonies

per 100 mL

Bacteria,

fecal

coliform, in

colonies per

100 mL

Aluminum,

dissolved,

in μg/L

-- -- -- 11 -- --

-- -- -- 2 -- --

2.3 ID 2 4 -- --

3.6 ID 2 4 -- --

1.1 ID 1 2 2 --

-- -- -- 3 3 --

1.8 ID 2 42 34 --

-- -- -- 34 40 --

0.6 ID 1 31 18 --

-- -- -- 6 12 --

1.2 ID 1 23 19 --

-- -- -- 20 24 --

1.6 ID 3 18 16 --

1.8 ID 3 52 55 <20

1.8 ID 2 40 23 <20

2.9 ID 2 10 -- <20

-- -- -- 100 -- --

-- -- -- 11 -- --

-- -- -- 24 -- --

-- -- -- 100 -- --

-- -- -- 56 -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

3.7 79.2 23 -- -- <20

4.3 87.5 23 -- -- <20

-- -- -- -- -- --

-- -- -- -- -- --

1.8 ID 2 17 10 --

-- -- -- -- -- --

-- -- -- 20 -- --

2 ID 3 11 7 --

-- -- -- 6 -- --

-- -- -- 7 -- --

-- -- -- 13 -- --
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

62 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002

20 8-1-2002

21 7-15-2002

9-4-2002

22 7-15-2002

9-4-2002

23 7-15-2002

9-4-2002

24 7-15-2002

9-4-2002

25 7-15-2002

9-4-2002

26 7-17-2002

9-6-2002

27 8-1-2002

28 8-8-2002

9-11-2002

29 8-8-2002

9-11-2002

30 7-29-2002

9-10-2002

31 7-29-2002

9-10-2002

32 8-8-2002

9-11-2002

33 7-30-2002

34 7-30-2002

35 7-30-2002

9-3-2002

36 7-30-2002

9-3-2002

37 7-31-2002

9-4-2002

Site number

in table 1

and fig. 4

Sampling date

Conc Q% N Conc Q% N

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- <2 ID 8 <2 ID 8

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

78 1 ID 14 1 ID 13

-- -- -- -- -- -- --

29 <2 ID 14 1 ID 12

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- <2 2

4.5–95.5 21 <2 24.8–90.5 20

-- -- -- -- -- -- --

Arsenic, dissolved, in μg/L

Aluminum,

total

recoverable,

in μg/L

Arsenic, total recoverable, in

μg/L
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

Appendix 63

Site number

in table 1

and fig. 4

Sampling date

38 8-1-2002

9-5-2002

39 8-1-2002

9-6-2002

40 7-29-2002

9-3-2002

41 7-29-2002

9-4-2002

42 7-30-2002

9-4-2002

43 7-30-2002

9-4-2002

44 7-30-2002

9-5-2002

45 7-31-2002

9-6-2002

46 8-2-2002

47 8-1-2002

9-3-2002

48 8-1-2002

9-5-2002

49 7-31-2002

50 7-31-2002

51 8-1-2002

52 8-1-2002

9-17-2002

53 7-31-2002

54 8-1-2002

55 7-30-2002

56 7-31-2002

9-5-2002

57 7-31-2002

9-4-2002

58 7-16-2002

9-5-2002

Conc Q% N Conc Q% N

Arsenic, dissolved, in μg/L

Aluminum,

total

recoverable,

in μg/L

Arsenic, total recoverable, in

μg/L

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

64 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002

20 8-1-2002

21 7-15-2002

9-4-2002

22 7-15-2002

9-4-2002

23 7-15-2002

9-4-2002

24 7-15-2002

9-4-2002

25 7-15-2002

9-4-2002

26 7-17-2002

9-6-2002

27 8-1-2002

28 8-8-2002

9-11-2002

29 8-8-2002

9-11-2002

30 7-29-2002

9-10-2002

31 7-29-2002

9-10-2002

32 8-8-2002

9-11-2002

33 7-30-2002

34 7-30-2002

35 7-30-2002

9-3-2002

36 7-30-2002

9-3-2002

37 7-31-2002

9-4-2002

Site number

in table 1

and fig. 4

Sampling date

Conc Q% N Conc Q% N

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- <0.1 ID 8 <0.1 ID 8

-- 0.05 ID 2 -- -- --

-- 0.02 ID 2 -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

80 <0.1 ID 14 <0.1 ID 14

-- -- -- -- -- -- --

60 <0.1 ID 14 <0.1 ID 14

-- -- -- -- -- -- --

-- 0.12 ID 2 -- -- --

-- 0.11 ID 2 -- -- --

-- <0.1 2

4.5–86.4 21 -- -- --

-- <0.1 ID 6 -- -- --

-- 0.1 ID 5 -- -- --

-- -- -- -- -- -- --

-- 0.2 ID 9 -- -- --

-- -- -- -- -- -- --

-- 0.1 2

4.3–82.6 22 0.1 24.5–86.4 21

-- 0.04 2

4.3–82.6 22 -- -- --

Cadmium, total recoverable, in

μg/L Cadmium, dissolved, in μg/L

Boron,

dissolved, in

μg/L
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

Appendix 65

Site number

in table 1

and fig. 4

Sampling date

38 8-1-2002

9-5-2002

39 8-1-2002

9-6-2002

40 7-29-2002

9-3-2002

41 7-29-2002

9-4-2002

42 7-30-2002

9-4-2002

43 7-30-2002

9-4-2002

44 7-30-2002

9-5-2002

45 7-31-2002

9-6-2002

46 8-2-2002

47 8-1-2002

9-3-2002

48 8-1-2002

9-5-2002

49 7-31-2002

50 7-31-2002

51 8-1-2002

52 8-1-2002

9-17-2002

53 7-31-2002

54 8-1-2002

55 7-30-2002

56 7-31-2002

9-5-2002

57 7-31-2002

9-4-2002

58 7-16-2002

9-5-2002

Conc Q% N Conc Q% N

Cadmium, total recoverable, in

μg/L Cadmium, dissolved, in μg/L

Boron,

dissolved, in

μg/L

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- <0.1 ID 6 -- -- --

-- -- -- -- -- -- --

-- 0.1 ID 5 -- -- --

-- -- -- -- -- -- --

-- 0.2 ID 6 -- -- --

-- -- -- -- -- -- --

-- 0.1 ID 3 -- -- --

-- -- -- -- -- -- --

-- <0.1 ID 10 -- -- --

-- 0.02 ID 10 -- -- --

-- 0.04 ID 2 -- -- --

-- <0.04 ID 2 -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- 0.03 ID 19 -- -- --

-- 0.03 ID 19 -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- <0.1 ID 5 -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- 0.2 ID 3 -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

66 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002

20 8-1-2002

21 7-15-2002

9-4-2002

22 7-15-2002

9-4-2002

23 7-15-2002

9-4-2002

24 7-15-2002

9-4-2002

25 7-15-2002

9-4-2002

26 7-17-2002

9-6-2002

27 8-1-2002

28 8-8-2002

9-11-2002

29 8-8-2002

9-11-2002

30 7-29-2002

9-10-2002

31 7-29-2002

9-10-2002

32 8-8-2002

9-11-2002

33 7-30-2002

34 7-30-2002

35 7-30-2002

9-3-2002

36 7-30-2002

9-3-2002

37 7-31-2002

9-4-2002

Site number

in table 1

and fig. 4

Sampling date

Conc Q% N Conc Q% N

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

<0.8 ID 8 <0.8 ID 8

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

<0.8 ID 14 <0.8 ID 14

-- -- -- -- -- --

<0.8 ID 14 <0.8 ID 14

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

<0.8 2

4.5–95.5 21 -- -- --

-- -- -- -- -- --

<0.8 ID 5 -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

<0.8 2

4.5–95.5 21 <0.8 24.5–63.6 21

-- -- -- -- -- --

Chromium, total recoverable, in

μg/L Chromium, dissolved, in μg/L
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

Appendix 67

Site number

in table 1

and fig. 4

Sampling date

38 8-1-2002

9-5-2002

39 8-1-2002

9-6-2002

40 7-29-2002

9-3-2002

41 7-29-2002

9-4-2002

42 7-30-2002

9-4-2002

43 7-30-2002

9-4-2002

44 7-30-2002

9-5-2002

45 7-31-2002

9-6-2002

46 8-2-2002

47 8-1-2002

9-3-2002

48 8-1-2002

9-5-2002

49 7-31-2002

50 7-31-2002

51 8-1-2002

52 8-1-2002

9-17-2002

53 7-31-2002

54 8-1-2002

55 7-30-2002

56 7-31-2002

9-5-2002

57 7-31-2002

9-4-2002

58 7-16-2002

9-5-2002

Conc Q% N Conc Q% N

Chromium, total recoverable, in

μg/L Chromium, dissolved, in μg/L

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

<0.8 ID 3 -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

68 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002

20 8-1-2002

21 7-15-2002

9-4-2002

22 7-15-2002

9-4-2002

23 7-15-2002

9-4-2002

24 7-15-2002

9-4-2002

25 7-15-2002

9-4-2002

26 7-17-2002

9-6-2002

27 8-1-2002

28 8-8-2002

9-11-2002

29 8-8-2002

9-11-2002

30 7-29-2002

9-10-2002

31 7-29-2002

9-10-2002

32 8-8-2002

9-11-2002

33 7-30-2002

34 7-30-2002

35 7-30-2002

9-3-2002

36 7-30-2002

9-3-2002

37 7-31-2002

9-4-2002

Site number

in table 1

and fig. 4

Sampling date

Conc Q% N Conc Q% N

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

0.8 ID 8 1 ID 8

0.9 ID 2 -- -- --

0.7 ID 2 -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

<1 ID 14 22 ID 14

-- -- -- -- -- --

0.8 ID 14 2.7 ID 14

-- -- -- -- -- --

1 ID 2 -- -- --

1.1 ID 2 -- -- --

0.9 2

4.2–87.5 23 -- -- --

<1 ID 6 -- -- --

1.6 ID 5 -- -- --

-- -- -- -- -- --

0.9 ID 9 -- -- --

-- -- -- -- -- --

0.9 2

4.3–39.1 22 1.6 140.9–45.5 21

2.6 87.0 22 -- -- --

Copper, dissolved, in μg/L Copper, total recoverable, in μg/L
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

Appendix 69

Site number

in table 1

and fig. 4

Sampling date

38 8-1-2002

9-5-2002

39 8-1-2002

9-6-2002

40 7-29-2002

9-3-2002

41 7-29-2002

9-4-2002

42 7-30-2002

9-4-2002

43 7-30-2002

9-4-2002

44 7-30-2002

9-5-2002

45 7-31-2002

9-6-2002

46 8-2-2002

47 8-1-2002

9-3-2002

48 8-1-2002

9-5-2002

49 7-31-2002

50 7-31-2002

51 8-1-2002

52 8-1-2002

9-17-2002

53 7-31-2002

54 8-1-2002

55 7-30-2002

56 7-31-2002

9-5-2002

57 7-31-2002

9-4-2002

58 7-16-2002

9-5-2002

Conc Q% N Conc Q% N

Copper, dissolved, in μg/L Copper, total recoverable, in μg/L

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

0.8 ID 6 -- -- --

-- -- -- -- -- --

<1 ID 5 -- -- --

-- -- -- -- -- --

<1 ID 6 -- -- --

-- -- -- -- -- --

<1 ID 3 -- -- --

-- -- -- -- -- --

0.8 ID 10 -- -- --

1.1 ID 10 -- -- --

1.2 ID 2 -- -- --

1.3 ID 2 -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

2.5 ID 19 -- -- --

2.8 ID 19 -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

0.7 ID 5 -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

1.9 ID 3 -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

70 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002

20 8-1-2002

21 7-15-2002

9-4-2002

22 7-15-2002

9-4-2002

23 7-15-2002

9-4-2002

24 7-15-2002

9-4-2002

25 7-15-2002

9-4-2002

26 7-17-2002

9-6-2002

27 8-1-2002

28 8-8-2002

9-11-2002

29 8-8-2002

9-11-2002

30 7-29-2002

9-10-2002

31 7-29-2002

9-10-2002

32 8-8-2002

9-11-2002

33 7-30-2002

34 7-30-2002

35 7-30-2002

9-3-2002

36 7-30-2002

9-3-2002

37 7-31-2002

9-4-2002

Site number

in table 1

and fig. 4

Sampling date

Conc Q% N Conc Q% N

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

339c ID 9 -- -- --

383c ID 9 -- -- --

231 ID 7 -- -- --

<10 ID 2 -- -- --

9 ID 2 -- -- --

45 ID 2 -- -- --

66 ID 2 -- -- --

42 70.8 47 330 1

39.3–50.0 27

32 1

58.3–60.4 47 330 139.3–50.0 27

<10 2

4.0–48.0 24 50 14.5–13.6 21

55 88.0 24 260 95.5 21

7 ID 2 -- -- --

28 ID 2 -- -- --

33 1

45.8–50 23 -- -- --

-- -- -- 90 ID 6

<10 ID 17 10 ID 5

-- -- -- -- -- --

-- -- -- 180 ID 9

-- -- -- -- -- --

7 13.3 29 -- -- --

13 1

26.7–33.3 29 -- -- --

Iron, dissolved, in μg/L Iron, total recoverable, in μg/L
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

Appendix 71

Site number

in table 1

and fig. 4

Sampling date

38 8-1-2002

9-5-2002

39 8-1-2002

9-6-2002

40 7-29-2002

9-3-2002

41 7-29-2002

9-4-2002

42 7-30-2002

9-4-2002

43 7-30-2002

9-4-2002

44 7-30-2002

9-5-2002

45 7-31-2002

9-6-2002

46 8-2-2002

47 8-1-2002

9-3-2002

48 8-1-2002

9-5-2002

49 7-31-2002

50 7-31-2002

51 8-1-2002

52 8-1-2002

9-17-2002

53 7-31-2002

54 8-1-2002

55 7-30-2002

56 7-31-2002

9-5-2002

57 7-31-2002

9-4-2002

58 7-16-2002

9-5-2002

Conc Q% N Conc Q% N

Iron, dissolved, in μg/L Iron, total recoverable, in μg/L

23 ID 14 -- -- --

15 ID 14 -- -- --

<10 ID 5 -- -- --

17 ID 5 -- -- --

-- -- -- 40 ID 6

-- -- -- -- -- --

-- -- -- 50 ID 5

-- -- -- -- -- --

-- -- -- 50 ID 6

-- -- -- -- -- --

-- -- -- 20 ID 3

-- -- -- -- -- --

-- -- -- 40 ID 9

5 ID 2 -- -- --

12 ID 2 -- -- --

7 ID 2 -- -- --

-- -- -- -- -- --

7 ID 19 -- -- --

8 ID 19 -- -- --

<10 ID 5 -- -- --

30 ID 5 -- -- --

<10 ID 2 -- -- --

6 ID 1 -- -- --

<10 ID 1 -- -- --

<10 2

2.2–63.0 45 -- -- --

<10 2

2.2–63.0 45 -- -- --

10 ID 1 -- -- --

<10 ID 1 -- -- --

-- -- -- 510 ID 5

11 ID 2 -- -- --

11 ID 2 -- -- --

25 ID 3 280 ID 3

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

72 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002

20 8-1-2002

21 7-15-2002

9-4-2002

22 7-15-2002

9-4-2002

23 7-15-2002

9-4-2002

24 7-15-2002

9-4-2002

25 7-15-2002

9-4-2002

26 7-17-2002

9-6-2002

27 8-1-2002

28 8-8-2002

9-11-2002

29 8-8-2002

9-11-2002

30 7-29-2002

9-10-2002

31 7-29-2002

9-10-2002

32 8-8-2002

9-11-2002

33 7-30-2002

34 7-30-2002

35 7-30-2002

9-3-2002

36 7-30-2002

9-3-2002

37 7-31-2002

9-4-2002

Site number

in table 1

and fig. 4

Sampling date

Conc Q% N Conc Q% N

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- 20 ID 9

-- -- -- 19.1 ID 9

0.09 ID 8 19.3 ID 7

<0.08 ID 2 6 ID 2

<0.08 ID 2 1.6 ID 2

-- -- -- -- -- --

-- -- -- -- -- --

<1 ID 14 60c 86.2 28

-- -- -- 115c 96.6 28

<1 ID 14 10.3 59.1 21

-- -- -- 250c 90.9 21

<0.08 ID 2 13.7 ID 2

0.13 ID 2 21 ID 2

<0.08 2

4.5–86.4 21 21 37.5 23

<1 ID 6 9.3 ID 6

0.05 ID 5 2 ID 17

-- -- -- -- -- --

<1 ID 9 15.5 ID 10

-- -- -- -- -- --

<1 2

4.3–95.7 22 21 26.7 29

0.07 2

4.3–95.7 22 29 46.7 29

Lead, dissolved, in μg/L Manganese, dissolved, in μg/L
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

Appendix 73

Site number

in table 1

and fig. 4

Sampling date

38 8-1-2002

9-5-2002

39 8-1-2002

9-6-2002

40 7-29-2002

9-3-2002

41 7-29-2002

9-4-2002

42 7-30-2002

9-4-2002

43 7-30-2002

9-4-2002

44 7-30-2002

9-5-2002

45 7-31-2002

9-6-2002

46 8-2-2002

47 8-1-2002

9-3-2002

48 8-1-2002

9-5-2002

49 7-31-2002

50 7-31-2002

51 8-1-2002

52 8-1-2002

9-17-2002

53 7-31-2002

54 8-1-2002

55 7-30-2002

56 7-31-2002

9-5-2002

57 7-31-2002

9-4-2002

58 7-16-2002

9-5-2002

Conc Q% N Conc Q% N

Lead, dissolved, in μg/L Manganese, dissolved, in μg/L

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

<1 ID 6 1.4 ID 6

-- -- -- -- -- --

<1 ID 5 5.6 ID 6

-- -- -- -- -- --

<1 ID 6 7.7 ID 6

-- -- -- -- -- --

<1 ID 3 4.1 ID 3

-- -- -- -- -- --

<1 ID 10 5 ID 11

0.14 ID 10 4.1 ID 11

0.07 ID 2 6.7 ID 2

0.09 ID 2 5.9 ID 2

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

0.05 ID 19 5.4 93.5 45

<0.08 ID 19 37 97.8 45

-- -- -- -- -- --

-- -- -- -- -- --

<1 ID 5 13.8 ID 5

-- -- -- -- -- --

-- -- -- -- -- --

0.12 ID 3 17.8 ID 3

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

74 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002

20 8-1-2002

21 7-15-2002

9-4-2002

22 7-15-2002

9-4-2002

23 7-15-2002

9-4-2002

24 7-15-2002

9-4-2002

25 7-15-2002

9-4-2002

26 7-17-2002

9-6-2002

27 8-1-2002

28 8-8-2002

9-11-2002

29 8-8-2002

9-11-2002

30 7-29-2002

9-10-2002

31 7-29-2002

9-10-2002

32 8-8-2002

9-11-2002

33 7-30-2002

34 7-30-2002

35 7-30-2002

9-3-2002

36 7-30-2002

9-3-2002

37 7-31-2002

9-4-2002

Site number

in table 1

and fig. 4

Sampling date

Conc Q% N Conc Q% N

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- <0.01 <0.01 ID 8

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

88 93.1 28 <0.01 <0.01 ID 14

141 96.6 28 -- -- -- 14

102 81.8 21 <0.01 <0.01 ID 14

296 90.9 21 -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

12.4 ID 6 <0.01 -- -- --

1.9 ID 5 <0.01 -- -- --

-- -- -- -- -- -- --

33 ID 9 <0.01 -- -- --

-- -- -- -- -- -- --

-- -- -- <0.01 <0.01 2

4.8–90.5 20

-- -- -- -- -- -- --

Manganese, total recoverable, in

μg/L

Mercury, total recoverable,

in μg/L

Mercury,

dissolved, in

μg/L
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

Appendix 75

Site number

in table 1

and fig. 4

Sampling date

38 8-1-2002

9-5-2002

39 8-1-2002

9-6-2002

40 7-29-2002

9-3-2002

41 7-29-2002

9-4-2002

42 7-30-2002

9-4-2002

43 7-30-2002

9-4-2002

44 7-30-2002

9-5-2002

45 7-31-2002

9-6-2002

46 8-2-2002

47 8-1-2002

9-3-2002

48 8-1-2002

9-5-2002

49 7-31-2002

50 7-31-2002

51 8-1-2002

52 8-1-2002

9-17-2002

53 7-31-2002

54 8-1-2002

55 7-30-2002

56 7-31-2002

9-5-2002

57 7-31-2002

9-4-2002

58 7-16-2002

9-5-2002

Conc Q% N Conc Q% N

Manganese, total recoverable, in

μg/L

Mercury, total recoverable,

in μg/L

Mercury,

dissolved, in

μg/L

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

2.7 ID 6 <0.01 -- -- --

-- -- -- -- -- -- --

10.6 ID 5 <0.01 -- -- --

-- -- -- -- -- -- --

7.8 ID 6 <0.01 -- -- --

-- -- -- -- -- -- --

3.5 ID 3 <0.01 -- -- --

-- -- -- -- -- -- --

8.9 ID 9 <0.01 -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

20 ID 5 <0.01 -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

39 ID 3 <0.01 -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

76 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002

20 8-1-2002

21 7-15-2002

9-4-2002

22 7-15-2002

9-4-2002

23 7-15-2002

9-4-2002

24 7-15-2002

9-4-2002

25 7-15-2002

9-4-2002

26 7-17-2002

9-6-2002

27 8-1-2002

28 8-8-2002

9-11-2002

29 8-8-2002

9-11-2002

30 7-29-2002

9-10-2002

31 7-29-2002

9-10-2002

32 8-8-2002

9-11-2002

33 7-30-2002

34 7-30-2002

35 7-30-2002

9-3-2002

36 7-30-2002

9-3-2002

37 7-31-2002

9-4-2002

Site number

in table 1

and fig. 4

Sampling date

Conc Q% N Conc Q% N

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- 0.23 ID 8

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

3.6 ID 14 3.6 ID 14

-- -- -- -- -- --

3.0 ID 14 2.8 ID 14

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

24 63.6 21 0.25 2

4.5–90.9 21

-- -- -- -- -- --

-- -- -- <0.06 ID 5

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- <2 ID 18

-- -- -- -- -- --

Nickel, dissolved, in μg/L Molybdenum, dissolved,

in μg/L
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

Appendix 77

Site number

in table 1

and fig. 4

Sampling date

38 8-1-2002

9-5-2002

39 8-1-2002

9-6-2002

40 7-29-2002

9-3-2002

41 7-29-2002

9-4-2002

42 7-30-2002

9-4-2002

43 7-30-2002

9-4-2002

44 7-30-2002

9-5-2002

45 7-31-2002

9-6-2002

46 8-2-2002

47 8-1-2002

9-3-2002

48 8-1-2002

9-5-2002

49 7-31-2002

50 7-31-2002

51 8-1-2002

52 8-1-2002

9-17-2002

53 7-31-2002

54 8-1-2002

55 7-30-2002

56 7-31-2002

9-5-2002

57 7-31-2002

9-4-2002

58 7-16-2002

9-5-2002

Conc Q% N Conc Q% N

Nickel, dissolved, in μg/L Molybdenum, dissolved,

in μg/L

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- 0.33 ID 3

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

78 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002

20 8-1-2002

21 7-15-2002

9-4-2002

22 7-15-2002

9-4-2002

23 7-15-2002

9-4-2002

24 7-15-2002

9-4-2002

25 7-15-2002

9-4-2002

26 7-17-2002

9-6-2002

27 8-1-2002

28 8-8-2002

9-11-2002

29 8-8-2002

9-11-2002

30 7-29-2002

9-10-2002

31 7-29-2002

9-10-2002

32 8-8-2002

9-11-2002

33 7-30-2002

34 7-30-2002

35 7-30-2002

9-3-2002

36 7-30-2002

9-3-2002

37 7-31-2002

9-4-2002

Site number

in table 1

and fig. 4

Sampling date

Conc Q% N Conc Q% N

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

<1 ID 8 <0.3 ID 8

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

6 ID 14 <2 ID 14

-- -- -- -- -- --

5 ID 14 2 ID 14

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- <2 ID 6

-- -- -- <0.3 ID 5

-- -- -- -- -- --

-- -- -- <2 ID 9

-- -- -- -- -- --

1.1 ID 18 <2 2

4.5–95.5 21

-- -- -- -- -- --

Nickel, total recoverable,

in μg/L Selenium, dissolved, in μg/L
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

Appendix 79

Site number

in table 1

and fig. 4

Sampling date

38 8-1-2002

9-5-2002

39 8-1-2002

9-6-2002

40 7-29-2002

9-3-2002

41 7-29-2002

9-4-2002

42 7-30-2002

9-4-2002

43 7-30-2002

9-4-2002

44 7-30-2002

9-5-2002

45 7-31-2002

9-6-2002

46 8-2-2002

47 8-1-2002

9-3-2002

48 8-1-2002

9-5-2002

49 7-31-2002

50 7-31-2002

51 8-1-2002

52 8-1-2002

9-17-2002

53 7-31-2002

54 8-1-2002

55 7-30-2002

56 7-31-2002

9-5-2002

57 7-31-2002

9-4-2002

58 7-16-2002

9-5-2002

Conc Q% N Conc Q% N

Nickel, total recoverable,

in μg/L Selenium, dissolved, in μg/L

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- 2 ID 6

-- -- -- -- -- --

-- -- -- <2 ID 5

-- -- -- -- -- --

-- -- -- <2 ID 6

-- -- -- -- -- --

-- -- -- <2 ID 3

-- -- -- -- -- --

-- -- -- <2 ID 9

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- 0.4 ID 19

-- -- -- 0.8 ID 19

-- -- -- 0.6 ID 7

-- -- -- -- -- --

-- -- -- 0.6 ID 9

-- -- -- 3.8 ID 7

-- -- -- 6.3c ID 7

-- -- -- 8.8c 83.3 47

-- -- -- 11c 95.8 47

-- -- -- 2.6 ID 4

-- -- -- 5.8c ID 7

-- -- -- <2 ID 5

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- 0.4 ID 3

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

80 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002

20 8-1-2002

21 7-15-2002

9-4-2002

22 7-15-2002

9-4-2002

23 7-15-2002

9-4-2002

24 7-15-2002

9-4-2002

25 7-15-2002

9-4-2002

26 7-17-2002

9-6-2002

27 8-1-2002

28 8-8-2002

9-11-2002

29 8-8-2002

9-11-2002

30 7-29-2002

9-10-2002

31 7-29-2002

9-10-2002

32 8-8-2002

9-11-2002

33 7-30-2002

34 7-30-2002

35 7-30-2002

9-3-2002

36 7-30-2002

9-3-2002

37 7-31-2002

9-4-2002

Site number

in table 1

and fig. 4

Sampling date

Conc Q% N Conc Q% N

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

<0.4 ID 8 <1 ID 8 <0.05

-- -- -- <1 ID 2 --

-- -- -- <1 ID 2 --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

0.7 ID 13 <0.1 ID 14 <0.05

-- -- -- -- -- -- --

2.7 ID 12 <0.1 ID 14 <0.05

-- -- -- -- -- -- --

-- -- -- <1 ID 2 --

-- -- -- <1 ID 2 --

-- -- -- <1 2

4.5–90.9 21 --

-- -- -- <0.1 ID 6 --

-- -- -- <1 ID 5 --

-- -- -- -- -- -- --

-- -- -- <0.1 ID 9 --

-- -- -- -- -- -- --

1.0 2

4.5–95.5 21 <0.1 ID 19 <0.3

-- -- -- <1 ID 19 --

Selenium, total recoverable, in

μg/L Silver, dissolved, in μg/L

Silver,

total

recoverable,

in μg/L
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

Appendixx 81

Site number

in table 1

and fig. 4

Sampling date

38 8-1-2002

9-5-2002

39 8-1-2002

9-6-2002

40 7-29-2002

9-3-2002

41 7-29-2002

9-4-2002

42 7-30-2002

9-4-2002

43 7-30-2002

9-4-2002

44 7-30-2002

9-5-2002

45 7-31-2002

9-6-2002

46 8-2-2002

47 8-1-2002

9-3-2002

48 8-1-2002

9-5-2002

49 7-31-2002

50 7-31-2002

51 8-1-2002

52 8-1-2002

9-17-2002

53 7-31-2002

54 8-1-2002

55 7-30-2002

56 7-31-2002

9-5-2002

57 7-31-2002

9-4-2002

58 7-16-2002

9-5-2002

Conc Q% N Conc Q% N

Selenium, total recoverable, in

μg/L Silver, dissolved, in μg/L

Silver,

total

recoverable,

in μg/L

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- <0.1 ID 6 --

-- -- -- -- -- -- --

-- -- -- <0.1 ID 5 --

-- -- -- -- -- -- --

-- -- -- <0.1 ID 6 --

-- -- -- -- -- -- --

-- -- -- <0.1 ID 3 --

-- -- -- -- -- -- --

-- -- -- <0.1 ID 10 --

-- -- -- <1 ID 10 --

-- -- -- <1 ID 2 --

-- -- -- <1 ID 2 --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- <1 2

4.3–87.0 22 --

-- -- -- <1 2

4.3–87.0 22 --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- <0.1 ID 5 --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- <1 ID 3 --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

82 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002

20 8-1-2002

21 7-15-2002

9-4-2002

22 7-15-2002

9-4-2002

23 7-15-2002

9-4-2002

24 7-15-2002

9-4-2002

25 7-15-2002

9-4-2002

26 7-17-2002

9-6-2002

27 8-1-2002

28 8-8-2002

9-11-2002

29 8-8-2002

9-11-2002

30 7-29-2002

9-10-2002

31 7-29-2002

9-10-2002

32 8-8-2002

9-11-2002

33 7-30-2002

34 7-30-2002

35 7-30-2002

9-3-2002

36 7-30-2002

9-3-2002

37 7-31-2002

9-4-2002

Site number

in table 1

and fig. 4

Sampling date

Conc Q% N Conc Q% N

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

2 ID 8 4 ID 8

5 ID 2 -- -- --

2 ID 2 -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

<24 ID 14 10 ID 14

-- -- -- -- -- --

<24 ID 14 2 ID 14

-- -- -- -- -- --

3 ID 2 -- -- --

2 ID 2 -- -- --

2 2

4.3–26.1 22 -- -- --

<24 ID 6 -- -- --

<24 ID 5 -- -- --

-- -- -- -- -- --

16 ID 9 -- -- --

-- -- -- -- -- --

<24 2

4.3–87.0 22 <20 4.8 20

5 2

4.3–87.0 22 -- -- --

Zinc, total recoverable,

in μg/L Zinc, dissolved, in μg/L
[ft3

/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance]

Table 12.  Water-quality data for the Upper Colorado River Basin, showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

1

 Possible percentile range because of uncensored ties in data. 

2

 Possible percentile range because of censored or recensored ties in data. 

Appendix 83

Site number

in table 1

and fig. 4

Sampling date

38 8-1-2002

9-5-2002

39 8-1-2002

9-6-2002

40 7-29-2002

9-3-2002

41 7-29-2002

9-4-2002

42 7-30-2002

9-4-2002

43 7-30-2002

9-4-2002

44 7-30-2002

9-5-2002

45 7-31-2002

9-6-2002

46 8-2-2002

47 8-1-2002

9-3-2002

48 8-1-2002

9-5-2002

49 7-31-2002

50 7-31-2002

51 8-1-2002

52 8-1-2002

9-17-2002

53 7-31-2002

54 8-1-2002

55 7-30-2002

56 7-31-2002

9-5-2002

57 7-31-2002

9-4-2002

58 7-16-2002

9-5-2002

Conc Q% N Conc Q% N

Zinc, total recoverable,

in μg/L Zinc, dissolved, in μg/L

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

<24 ID 6 -- -- --

-- -- -- -- -- --

<24 ID 5 -- -- --

-- -- -- -- -- --

<24 ID 6 -- -- --

-- -- -- -- -- --

<24 ID 3 -- -- --

-- -- -- -- -- --

<24 ID 10 -- -- --

2 ID 10 -- -- --

1 ID 2 -- -- --

2 ID 2 -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

1 ID 19 -- -- --

2 ID 19 -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

<24 ID 5 -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

<24 ID 3 -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --
Conc Q% N Value Q% N

59 9-18-2002 1015 158 8.3 ID 2 7.9 ID 1

60 9-18-2002 1315 33 8.4 ID 1 8.3 ID 1

61 7-11-2002 1130 12 9.5 1

88.2–91.2 33 8.6 151.4–62.2 36

8-15-2002 1030 7 7.6 1

35.3–41.2 33 9.0 191.9–97.3 36

62 9-18-2002 0745 100 8.2 ID 1 7.6 ID 1

Site number

in table 1

and fig. 5

Sampling

time

Discharge,

in ft

3

/s

Sampling

date

Oxygen, dissolved, in mg/L pH, in standard units

59 9-18-2002

60 9-18-2002

61 7-11-2002

8-15-2002

62 9-18-2002

Site number

in table 1

and fig. 5

Sampling

date

Value Q% N Value Q% N

111 ID 2 11.5 1

17.4–21.7 45 36

90 ID 1 11.5 24.4 44 37

461 68.6 34 21.5 1

83.9–87.5 55 84

450 62.9 34 18.5 1

33.9–37.5 55 58

89 ID 1 9.5 ID 1 34

Specific conductance, in μS/cm Temperature, water, in o

C Hardness,

total, in mg/L

as CaCO3

59 9-18-2002

60 9-18-2002

61 7-11-2002

8-15-2002

62 9-18-2002

Site number

in table 1

and fig. 5

Sampling

date

Conc Q% N

11.7 1.71 1.93 4.3 1.37 ID 2

11.7 1.89 1.75 2.7 0.50 ID 1

21 7.8 7.8 64 15.4 85.7 34

12.1 6.7 8.3 70 17.6 97.1 34

10.7 1.71 1.94 3.8 0.89 ID 1

Chloride, dissolved, in mg/L Sodium,

dissolved,

in mg/L

Potassium,

dissolved,

in mg/L

Magnesium,

dissolved,

in mg/L

Calcium,

dissolved, in

mg/L

59 9-18-2002

60 9-18-2002

61 7-11-2002

8-15-2002

62 9-18-2002

Site number

in table 1

and fig. 5

Sampling

date

Conc Q% N Conc Q% N

0.1 ID 2 19.0 ID 2

0.1 ID 1 20 ID 1

0.86 91.4 34 17.8 11.4 34

1.1 97.1 34 8.79 2.9 34

0.1 ID 1 21 ID 1

Fluoride, dissolved, in mg/L Silica, dissolved, in mg/L as SiO2

Table 13.  Water-quality data for the Rio Grande Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3

, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of samples 

(less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado water-quality exceedances; ac, acute and chronic water-quality exceedance]

84 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
59 9-18-2002

60 9-18-2002

61 7-11-2002

8-15-2002

62 9-18-2002

Site number

in table 1

and fig. 5

Sampling

date

Conc Q% N Conc Q% N

9.6 ID 2 82 <0.015 ID 2

2.4 ID 1 74 <0.015 ID 1

51 65.7 34 284 <0.04 2

3.2–77.4 30

53 68.6 34 263 <0.04 2

3.2–77.4 30

6.3 ID 1 69 <0.015 ID 1

Sulfate dissolved, in mg/L as SO4

Nitrogen, ammonia, dissolved,

in mg/L as N

Solids, dissolved,

residue on

evaporation at

180 o

C, in mg/L

59 9-18-2002

60 9-18-2002

61 7-11-2002

8-15-2002

62 9-18-2002

Site number

in table 1

and fig. 5

Sampling

date

Conc Q% N Conc Q% N

0.12 ID 2 0.18 ID 2

0.12 ID 1 0.12 ID 1

0.38 57.7 25 0.64 54.1 36

0.43 65.4 25 0.68 56.8 36

0.10 ID 1 0.15 ID 1

Nitrogen, organic plus ammonia, total

recoverable, in mg/L as N

Nitrogen, organic plus ammonia,

dissolved, in mg/L as N

59 9-18-2002

60 9-18-2002

61 7-11-2002

8-15-2002

62 9-18-2002

Site number

in table 1

and fig. 5

Sampling

date

Conc Q% N Conc Q% N

<0.013 ID 2 <0.002 ID 2

<0.013 ID 1 <0.002 ID 1

<0.05 2

3.0–87.9 32 <0.008 24.8–95.2 20

<0.05 2

3.0–87.9 32 <0.008 24.8–95.2 20

<0.013 ID 1 <0.002 ID 1

Nitrogen, nitrite plus nitrate, dissolved,

in mg/L as N

Nitrogen, nitrite, dissolved,

in mg/L as N

59 9-18-2002

60 9-18-2002

61 7-11-2002

8-15-2002

62 9-18-2002

Site number

in table 1

and fig. 5

Sampling

date

Conc Q% N Conc Q% N

0.036 ID 2 0.051 ID 2

0.015 ID 1 0.025 ID 1

0.011 1

5.4–8.1 36 0.069 8.1 36

0.013 10.8 36 0.061 1

2.7–5.4 36

0.031 ID 1 0.043 ID 1

Phosphorus, dissolved, in mg/L as P Phosphorus, total recoverable,

in mg/L as P

Table 13.  Water-quality data for the Rio Grande Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3

, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of samples 

(less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado water-quality exceedances; ac, acute and chronic water-quality exceedance]

Appendix 85
59 9-18-2002

60 9-18-2002

61 7-11-2002

8-15-2002

62 9-18-2002

Site number

in table 1

and fig. 5

Sampling

date

Conc Q% N

22 ID 1 <0.06 0.18 0.07 <0.8

17 ID 1 <0.06 <0.04 0.06 <0.8

34 57.1 20 <0.06 0.03 <3 <0.8

-- -- -- -- -- -- --

18 ID 1 <0.06 <0.04 0.07 <0.8

Chromium,

dissolved,

in μg/L

Cadmium,

dissolved,

in μg/L

Cobalt,

dissolved,

in μg/L

Beryllium,

dissolved,

in μg/L

Barium, dissolved, in mg/L

59 9-18-2002

60 9-18-2002

61 7-11-2002

8-15-2002

62 9-18-2002

Site number

in table 1

and fig. 5

Sampling

date

Conc Q% N

0.028 ID 2 1.7 2.2 13

0.012 ID 1 1.2 1.8 3

<0.02 2

4.0–16.0 24 -- -- 20

<0.03 2

4.0–16.0 24 -- -- 14

0.025 ID 1 1.6 2.1 11

Carbon,

organic,

dissolved,

in mg/L

Carbon,

organic, total

recoverable,

in mg/L

Bacteria,

E. coli ,

in colonies

per 100 mL

Phosphorus, orthophosphate, dissolved, in

mg/L as P

59 9-18-2002

60 9-18-2002

61 7-11-2002

8-15-2002

62 9-18-2002

Site number

in table 1

and fig. 5

Sampling

date

Conc Q% N

14 ID 1 5 1 --

5 ID 1 2 1 --

-- -- -- 6 5 --

11 40.9 21 -- -- --

7 ID 1 4 1 --

Bacteria, fecal coliform, in colonies per

100 mL Aluminum,

dissolved,

in μg/L

Arsenic,

dissolved,

in μg/L

Arsenic,

total

recoverable,

in μg/L

Table 13.  Water-quality data for the Rio Grande Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3

, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of samples 

(less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado water-quality exceedances; ac, acute and chronic water-quality exceedance]

86 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
1

 Possible percentile range because of uncensored ties in data.

2

 Possible percentile range because of censored or recensored ties in data.

59 9-18-2002

60 9-18-2002

61 7-11-2002

8-15-2002

62 9-18-2002

Site number

in table 1

and fig. 5

Sampling

date

Conc Q% N Conc Q% N

1 -- -- -- 0.34 11.3 ID 2

0.3 -- -- -- <0.08 4 ID 1

-- 7 2

3.7–22.2 26 0.13 20.3 184.0–88.0 24

-- 14 29.6 26 -- 20.3 1

84.0–88.0 24

0.6 -- -- -- <0.08 10.1 ID 1

Lead,

dissolved, in

μg/L

Copper,

dissolved,

in μg/L

Iron, dissolved, in μg/L Manganese, dissolved,

in μg/L

59 9-18-2002

60 9-18-2002

61 7-11-2002

8-15-2002

62 9-18-2002

Site number

in table 1

and fig. 5

Sampling

date

Conc Q% N Conc Q% N

0.5 0.66 <2 ID 2 <1 ID 1

0.2 0.47 <2 ID 1 <1 ID 1

8.1 0.81 <2 2

4.8–95.2 20 <1 24.8–95.2 20

-- -- -- -- -- -- -- --

0.4 0.47 <2 ID 1 <1 ID 1

Molybdenum,

dissolved,

in μg/L

Nickel,

dissolved,

in μg/L

Selenium, dissolved, in μg/L Silver, dissolved, in μg/L

59 9-18-2002

60 9-18-2002

61 7-11-2002

8-15-2002

62 9-18-2002

Site number

in table 1

and fig. 5

Sampling

date

54ac 0.21

<1 0.05

1 1.96

-- --

<1 0.12

Zinc,

dissolved,

in μg/L

Uranium,

dissolved,

in μg/L

Table 13.  Water-quality data for the Rio Grande Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3

, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of samples 

(less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado water-quality exceedances; ac, acute and chronic water-quality exceedance]

Appendix 87
Conc Q% N Value Q% N Value Q% 

63 8-6-2002 0905 79 7.6 114.8–18.5 26 8.2 122.2–33.3 26 323 86.8 

9-3-2002 1740 43 7.3 11.1 26 8.4 159.3–92.6 26 335 94.7 

64 8-6-2002 0900 119 8.1 140.9–50.0 21 8.2 118.2–31.8 21 343 92.6 

9-4-2002 1040 36 8.3 163.6–68.2 21 8.4 154.5–72.7 21 351 95.6 

65 8-6-2002 1330 9.4 7.4 ID 8 8.5 ID 8 382 ID 

9-4-2002 1210 5.2 8.3 ID 8 8.6 ID 8 397 ID 

66 8-7-2002 0905 357 8.4 ID 14 8.2 ID 14 232 87.0 67 8-7-2002 0910 39 7.7 ID 19 8.2 ID 19 377 94.2 

9-4-2002 1350 18 9.9 ID 19 8.6 ID 19 330 171.0–72.5 

68 8-7-2002 1239 482 8.4 112.5–16.7 23 8.4 95.8 23 212 77.1 

9-5-2002 1440 444 8.6 125.0–33.3 23 8.3 91.7 23 218 84.3 

69 8-8-2002 0930 48 7.5 ID 2 8.2 ID 2 1,590 ID 

9-10-2002 1320 44 7.2 ID 2 8.2 ID 2 1,500 ID 

70 8-8-2002 1415 607 10.6 ID 6 8.6 ID 14 794 39.1 

9-11-2002 0910 497 6.9 ID 6 8.1 ID 14 1,010 68.8 

71 8-7-2002 0850 45 8 ID 3 8.0 ID 3 538 ID 72 8-7-2002 1025 69 8.1 ID 14 8.3 ID 16 700 81.7 73 8-13-2002 1000 109 8.6 ID 9 8.2 121.4–75.0 27 1,760 90.4 

9-23-2002 0900 246 8.2 ID 9 8.2 121.4–75.0 27 1,640 72.6 

74 8-13-2002 1300 818 8.5 176.8–78.6 55 8.4 162.7–86.4 58 1,130 69.9 

9-24-2002 1000 1,010 7.6 133.9–37.5 55 8.4 162.7–86.4 58 1,250 82.2 

75 8-7-2002 1035 354 8.4 ID 17 8.3 ID 17 255 ID 

9-5-2002 0830 116 8.1 ID 17 8.2 ID 17 288 ID 

76 8-6-2002 1500 28 9.4 ID 3 8.8 ID 4 290 ID 77 8-6-2002 1140 8.3 7.6 ID 3 8.4 ID 3 198 ID 78 8-8-2002 1230 500 8.5 ID 15 8.2 ID 16 432 ID 79 8-6-2002 1010 43 7.9 ID 2 8.4 ID 2 331 ID 80 8-5-2002 1600 2.6 7.1 ID 2 8.2 ID 2 328 ID 81 8-5-2002 1410 9.2 6.1 ID 16 7.5 ID 16 136 ID 82 8-5-2002 1240 1.8 6.1 ID 2 8.3 ID 2 280 ID 83 8-5-2002 1630 14 6.6 ID 12 8.3 ID 12 385 ID 

Site

number in

table 1

and fig. 5

Sampling

date

Sampling

time

Discharge,

in ft3/s

Oxygen, dissolved, in mg/L pH, in standard units Specific conductance, 

Table 14.   Water-quality data for the Gunnison River Basin showing 2002 drought values, Colorado water-quality exceedances, andpercentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample ent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees Celsius; EEscherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of samples (less thato calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado water-quality exceedanchronic water-quality exceedance]
63 8-6-2002

9-3-2002

64 8-6-2002

9-4-2002

65 8-6-2002

9-4-2002

66 8-7-200267 8-7-2002

9-4-2002

68 8-7-2002

9-5-2002

69 8-8-2002

9-10-2002

70 8-8-2002

9-11-2002

71 8-7-200272 8-7-200273 8-13-2002

9-23-2002

74 8-13-2002

9-24-2002

75 8-7-2002

9-5-2002

76 8-6-200277 8-6-200278 8-8-200279 8-6-200280 8-5-200281 8-5-200282 8-5-200283 8-5-2002

Site

number in

table 1

and fig. 5

Sampling

date

Value Q% N Conc Q

12.0 155.3–57.9 37 150 49 7.8 1.02 3.8 135 2.0 96

14.0 178.9–81.6 37 160 51 9.0 1.18 4.8 135 1.98 9212.7 48.5 67 170 54 8.5 1.04 3.8 150 1.34 I12.0 132.4–42.6 67 180 56 9.3 1.24 4.2 158 1.44 I21.5 ID 9 190 54 13.7 1.91 6.4 199 1.69 I15.5 ID 9 210 58 15.3 2.0 6.8 198 2.3 I13.0 134.2–42.1 75 110 33 6.7 0.91 3.0 104 1.34 I14.5 125.0–26.5 67 190 53 13.3 2.7 8.5 181 4.0 I20.0 169.1–75.0 67 170 47 12.6 2.3 5.7 158 3.8 I12.5 165.7–72.9 69 93 28 5.7 1.53 4.6 90 1.22 I14.0 192.9–98.6 69 100 31 6.2 1.49 4.8 91 1.65 I17.0 ID 16 830 210 74 4.6 73 272 7.2 I22.0 ID 16 760 194 67 5.3 75 271 9.2 I22.0 193.0–95.8 70 330 90 26 3.4 46 143 7.2 I18.0 153.5–62.0 70 -- -- -- -- -- -- -- -13.5 ID 3 250 92 4.3 1.37 11.2 32 4.2 I13.0 129.5–34.4 60 330 111 13.7 2.6 25 138 5.7 I16.0 123.3–30.1 72 800 224 58 3.5 111 269 10.8 8212.0 4.1 72 750 208 55 3.9 106 155 10.0 6220.0 172.7–75.3 76 490 135 37 3.8 64 169 8.9 7215.0 19.1–10.4 76 550 155 41 3.8 74 127 10 8214.7 ID 17 120 36 7.7 1.14 3.9 114 1.51 I11.0 ID 17 150 44 9.1 1.3 4.2 131 1.9 I21.4 ID 3 140 39 9.6 2.4 8.6 149 2.2 I14.8 ID 3 96 28 6.2 0.84 2.0 94 0.34 I17.0 ID 4 180 47 14.7 2.5 19.2 114 6 I14.0 ID 15 160 53 7.7 0.88 2.1 137 0.41 I16.3 ID 2 130 44 4.8 -- -- -- -- -14.9 ID 16 58 19.6 2.2 -- -- -- -- -18.0 ID 2 -- -- -- -- -- -- -- -18.5 ID 12 160 51.1 7.2 0.73 2.2 129 0.55 I

Sodium,

dissolved,

in mg/L

Acidneutralizing

capacity,

in mg/L as

CaCO3

Chloride, diss

Hardness,

total, in mg/L

as CaCO3

Calcium,

dissolved,

in mg/L

Magnesium,

dissolved,

in mg/L

Potassium,

dissolved,

in mg/L

Temperature, water, in oC

Table 14.   Water-quality data for the Gunnison River Basin showing 2002 drought values, Colorado water-quality exceedances, and percrelative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample consnumber of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees Celsius; E. coli, Escherichia 

liliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of samples (less than 20) to calculate percentile; <drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado water-quality exceedances; c, chronic water-quality exceedance]
63 8-6-2002

9-3-2002

64 8-6-2002

9-4-2002

65 8-6-2002

9-4-2002

66 8-7-200267 8-7-2002

9-4-2002

68 8-7-2002

9-5-2002

69 8-8-2002

9-10-2002

70 8-8-2002

9-11-2002

71 8-7-200272 8-7-200273 8-13-2002

9-23-2002

74 8-13-2002

9-24-2002

75 8-7-2002

9-5-2002

76 8-6-200277 8-6-200278 8-8-200279 8-6-200280 8-5-200281 8-5-200282 8-5-200283 8-5-2002

Site

number in

table 1

and fig. 5

Sampling

date

Conc Q% N Conc Q% N Conc Q% N Conc Q% 

-- -- -- 7.1 65.4 25 32 80.8 25 <0.015 23.7–66.7 

-- -- -- 8.2 96.2 25 34 96.2 25 <0.015 23.7–66.7 -- -- -- 8.0 ID 8 28 ID 8 <0.015 ID -- -- -- 9.2 ID 8 27 ID 8 <0.015 ID -- -- -- 19.1 ID 2 14.5 ID 2 <0.015 ID -- -- -- 19.3 ID 2 18.2 ID 2 <0.015 ID -- -- -- 8.6 ID 6 14.6 ID 6 <0.015 ID -- -- -- 20.4 ID 8 17.5 ID 8 0.009 ID -- -- -- 14.4 ID 8 16.1 ID 8 <0.015 ID -- -- -- 10.4 ID 16 17.3 ID 17 <0.015 24.3–69.6 -- -- -- 10.5 ID 16 18.0 ID 17 <0.015 24.3–69.6 -- -- -- 17.7 ID 2 646 ID 2 <0.04 ID -- -- -- 20.4 ID 2 608 ID 2 0.028 ID 

0.3 ID 10 11.8 ID 10 261 ID 11 -- -- 

-- -- -- -- -- -- -- -- -- -- -- 

0.6 ID 3 9.7 ID 3 223 ID 3 <0.015 ID 0.5 ID 13 11.2 ID 13 225 ID 13 <0.015 ID 

-- -- -- 17.5 164.3–67.9 27 743 89.7 28 <0.04 ID 

0.8 170.4–85.2 26 17.5 164.3–67.9 27 702 75.9 28 -- -- 

-- -- -- 11.0 16.9–10.3 57 433 72.4 57 <0.04 22.3–68.2 

-- -- -- 14.7 65.5 57 503 81.0 57 <0.04 22.3–68.2 -- -- -- 10.1 ID 11 15.6 ID 11 <0.015 ID -- -- -- 11.2 ID 11 16.4 ID 11 <0.015 ID -- -- -- 17.4 ID 2 8.0 ID 2 <0.015 ID -- -- -- 9.6 ID 1 8.0 ID 1 <0.015 ID 

0.3 ID 6 10.6 ID 7 94 ID 7 -- -- 

-- -- -- 6.4 ID 0 37 ID 0 <0.015 ID -- -- -- -- -- -- -- -- -- <0.015 ID -- -- -- -- -- -- -- -- -- <0.015 ID -- -- -- -- -- -- -- -- -- <0.015 ID -- -- -- 5.8 ID 4 34 ID 4 <0.015 ID 

Fluoride, dissolved, in mg/L Silica, dissolved, in mg/L as SiO2 Sulfate dissolved, in mg/L as SO4 Nitrogen, ammonia, d

in mg/L as N

Table 14.   Water-quality data for the Gunnison River Basin showing 2002 drought values, Colorado water-quality exceedances, andpercentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample ent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees Celsius; E. Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of samples (less thacalculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado water-quality exceedancewater-quality exceedance]
63 8-6-2002

9-3-2002

64 8-6-2002

9-4-2002

65 8-6-2002

9-4-2002

66 8-7-200267 8-7-2002

9-4-2002

68 8-7-2002

9-5-2002

69 8-8-2002

9-10-2002

70 8-8-2002

9-11-2002

71 8-7-200272 8-7-200273 8-13-2002

9-23-2002

74 8-13-2002

9-24-2002

75 8-7-2002

9-5-2002

76 8-6-200277 8-6-200278 8-8-200279 8-6-200280 8-5-200281 8-5-200282 8-5-200283 8-5-2002

Site

number in

table 1

and fig. 5

Sampling

date

Conc Q% N Conc Q% N Conc Q% N Conc Q% 

0.07 23.7–96.3 26 0.1 23.8–96.2 25 0.049 23.7–40.7 26 0.002 23.7–80.06 23.7–96.3 26 0.08 23.8–96.2 25 0.027 23.7–40.7 26 <0.002 23.7–8

ID ID 18 0.11 ID 17 0.016 ID 18 <0.002 ID ID ID 18 0.08 ID 17 0.011 ID 18 <0.002 ID ID ID 8 0.23 ID 8 <0.013 ID 8 <0.002 ID ID ID 8 0.17 ID 8 <0.013 ID 8 <0.002 ID ID ID 14 0.13 ID 14 0.012 ID 14 <0.002 ID ID ID 16 0.41 ID 16 0.020 ID 16 0.002 ID ID ID 16 0.22 ID 16 <0.013 ID 16 <0.002 ID 

0.11 24.8–95.2 20 -- -- -- <0.013 24.3–65.2 22 <0.002 24.3–9

0.12 24.8–95.2 20 -- -- -- <0.013 24.3–65.2 22 <0.002 24.3–9

ID ID 2 -- -- -- <0.05 ID 2 <0.008 ID ID ID 2 -- -- -- 0.083 ID 2 0.017 ID 

-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 

ID ID 3 0.08 ID 3 0.265 ID 3 <0.002 ID ID ID 13 0.29 ID 13 0.219 ID 13 0.004 ID ID ID 2 -- -- -- 4.0 ID 10 0.013 ID 

-- -- -- -- -- -- -- -- -- -- -- 

0.28 50.0 23 -- -- -- 1.46 68.2 43 0.006 22.9–5

0.27 45.8 23 -- -- -- 1.58 75.0 43 0.005 22.9–5

ID ID 17 0.17 ID 17 0.037 ID 17 <0.002 ID ID ID 17 0.12 ID 17 0.078 ID 17 0.002 ID ID ID 4 0.27 ID 4 <0.013 ID 4 <0.002 ID ID ID 3 0.1 ID 3 0.021 ID 3 <0.002 ID 

-- -- -- -- -- -- -- -- -- -- -- 

ID ID 2 0.11 ID 2 0.023 ID 2 <0.002 ID ID ID 2 0.08 ID 2 0.026 ID 2 <0.002 ID ID ID 16 <0.1 ID 16 0.045 ID 16 <0.002 ID ID ID 2 0.48 ID 2 2.7 ID 2 0.021 ID ID ID 12 0.11 ID 12 <0.013 ID 12 <0.002 ID 

Nitrogen, organic plus ammonia,

dissolved, in mg/L as N

Nitrogen, organic plus ammonia, total

recoverable, in mg/L as N

Nitrogen, nitrite plus nitrate, dissolved,

in mg/L as N

Nitrogen, nitrite

in mg/L 

Table 14.   Water-quality data for the Gunnison River Basin showing 2002 drought values, Colorado water-quality exceedances, and perceto historical data for selected properties and constituents from July through September, 1978–2002.—Continued[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample constitnumber of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees Celsius; E. coli, Escherichia cliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of samples (less than 20) to calculate percentile; <, ldrought-sample measurement; values or concentrations in bold type indicate 2002 Colorado water-quality exceedances; c, chronic water-quality exceedance]
63 8-6-2002

9-3-2002

64 8-6-2002

9-4-2002

65 8-6-2002

9-4-2002

66 8-7-200267 8-7-2002

9-4-2002

68 8-7-2002

9-5-2002

69 8-8-2002

9-10-2002

70 8-8-2002

9-11-2002

71 8-7-200272 8-7-200273 8-13-2002

9-23-2002

74 8-13-2002

9-24-2002

75 8-7-2002

9-5-2002

76 8-6-200277 8-6-200278 8-8-200279 8-6-200280 8-5-200281 8-5-200282 8-5-200283 8-5-2002

Site

number in

table 1

and fig. 5

Sampling

date

Conc Q% N Conc Q% N Conc Q% N

0.003 23.7–92.6 26 0.008 23.8–80.8 25 <0.007 23.7–92.6 26 -- 73 -- 

0.004 23.7–92.6 26 0.008 23.8–80.8 25 <0.007 23.7–92.6 26 -- 4 -- 

<0.004 ID 18 0.011 ID 17 <0.007 ID 18 -- 65 -- <0.004 ID 18 0.005 ID 17 <0.007 ID 18 -- 13 -- 

0.039 ID 8 0.06 ID 8 0.029 ID 8 2.7 75 -- 

0.03 ID 8 0.041 ID 8 0.022 ID 8 2.4 41 -- 

0.004 ID 13 0.016 ID 14 <0.007 ID 14 -- 38 -- 0.027 ID 16 0.043 ID 16 0.014 ID 16 4.7 120 -- 0.011 ID 16 0.022 ID 16 0.005 ID 16 2.8 51 -- 

0.01 154.5–59.1 21 0.017 140.9–45.5 21 0.007 24.3–47.8 22 2.1 <1 -- 0.01 154.5–59.1 21 0.023 159.1–63.6 21 0.008 24.3–47.8 22 2.7 <1 -- 

<0.06 ID 2 0.080 ID 2 <0.02 ID 2 4.8 580 -- 

0.056 ID 2 0.23 ID 2 0.044 ID 2 5.3 210 -- 

-- -- -- -- -- -- -- -- -- -- 52 -- -- -- -- -- -- -- -- -- -- -- -- -- 

<0.004 ID 3 0.16 ID 3 <0.007 ID 3 0.5 6 25 

0.009 ID 13 0.18 ID 13 0.004 ID 13 1.8 210 126 

<0.06 ID 3 0.15 ID 3 <0.02 ID 3 4.9 280 -- 

-- -- -- -- -- -- -- -- -- -- 210 -- 

<0.06 22.1–87.5 47 0.060 131.9–38.3 46 <0.02 22.5–70.0 39 3.8 8 -- 

<0.06 22.1–87.5 47 0.20 89.4 46 <0.02 22.5–70.0 39 4.2 47 -- 

0.01 ID 17 0.021 ID 17 0.006 ID 17 2 65 -- 

0.021 ID 17 0.030 ID 17 0.016 ID 17 2.1 37 -- 

0.05 ID 4 0.068 ID 4 0.039 ID 4 3.1 73 -- 

0.003 ID 3 0.009 ID 3 <0.007 ID 3 1.7 3 -- 

-- -- -- -- -- -- -- -- -- -- 10 -- 

0.003 ID 2 0.010 ID 2 <0.007 ID 2 -- 72 -- 

<0.004 ID 2 0.005 ID 2 <0.007 ID 2 1.3 12 -- <0.004 ID 16 0.002 ID 16 <0.007 ID 16 0.6 21 -- 

0.6 ID 2 0.67 ID 2 0.556 ID 2 -- 800 -- 

<0.004 ID 12 0.006 ID 12 <0.007 ID 12 -- 6 -- 

Phosphorus, orthophosphate,

dissolved, in mg/L as P

Phosphorus, total recoverable,

in mg/L as P Phosphorus, dissolved, in mg/L as P Carbon,

organic,

dissolved,

in mg/L

Bacteria,

E. coli ,

in colonies

per 100 mL

Bacteria, fe

coliform, i

colonies

per 100 mL

Table 14.   Water-quality data for the Gunnison River Basin showing 2002 drought values, Colorado water-quality exceedances, and percentiles rfor selected properties and constituents from July through September, 1978–2002.—Continued[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample constituent; Nand drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, miccalcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; valutype indicate 2002 Colorado water-quality exceedances; c, chronic water-quality exceedance]
63 8-6-2002

9-3-2002

64 8-6-2002

9-4-2002

65 8-6-2002

9-4-2002

66 8-7-200267 8-7-2002

9-4-2002

68 8-7-2002

9-5-2002

69 8-8-2002

9-10-2002

70 8-8-2002

9-11-2002

71 8-7-200272 8-7-200273 8-13-2002

9-23-2002

74 8-13-2002

9-24-2002

75 8-7-2002

9-5-2002

76 8-6-200277 8-6-200278 8-8-200279 8-6-200280 8-5-200281 8-5-200282 8-5-200283 8-5-2002

Site

number in

table 1

and fig. 5

Sampling

date

Conc Q% N Conc Q% N Conc Q% N Conc Q% 

-- -- -- -- -- -- 6 24.0–40.0 24 -- -- -- 

-- -- -- -- -- -- 6 24.0–40.0 24 -- -- -- -- -- -- -- -- -- 8 ID 9 -- -- -- -- -- -- -- -- -- 10 ID 9 -- -- -- 

<0.04 ID 3 0.5 ID 3 33 ID 3 -- <0.08 ID <0.04 ID 3 0.6 ID 3 15 ID 3 -- <0.08 ID 

-- -- -- -- -- -- 9 ID 5 -- -- -- 

<0.1 ID 12 0.8 ID 12 48 ID 8 -- <1 ID 

<0.04 ID 12 0.6 ID 12 26 ID 8 -- 0.09 ID <0.04 ID 6 0.7 ID 6 <10 ID 15 -- 0.04 ID <0.04 ID 6 0.7 ID 6 <10 ID 15 -- 0.11 ID 

0.02 ID 2 2.7 ID 2 7 ID 2 -- <0.08 ID 

<0.04 ID 2 2.8 ID 2 <10 ID 2 -- <0.08 ID 

-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 

0.3 ID 3 2.9 ID 3 -- -- -- 4,050c <1 ID 0.1 ID 13 2.3 ID 13 -- -- -- 2,640c <1 ID 

0.03 ID 7 4.2 ID 7 <10 ID 3 -- 0.06 ID 

-- -- -- -- -- -- -- -- -- -- -- -- 

<0.04 23.8–92.3 25 2.7 61.5 25 <10 22.3–65.1 42 -- <0.08 23.8–88.

0.02 23.8–92.3 25 4 173.1–80.8 25 <10 22.3–65.1 42 -- <0.08 23.8–88.

<0.2 ID 9 <3 ID 9 13 ID 15 -- 3 ID 

<0.04 ID 9 0.5 ID 9 19 ID 15 -- <0.08 ID 

<0.1 ID 2 0.7 ID 2 45 ID 3 -- <1 ID <0.1 ID 2 1 ID 2 76 ID 2 -- 1 ID 

-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 8 ID 2 -- -- -- 

0.3 ID 2 <1 ID 2 7 ID 2 -- <1 ID 0.1 ID 8 0.6 ID 8 17 ID 9 -- 1 ID 

-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 38 ID 2 -- -- -- 

Iron, total

recoverable,

in μg/L

Cadmium, dissolved, in mg/L Copper, dissolved, in μg/L Iron, dissolved, in μg/L Lead, dissolved, 

Table 14.   Water-quality data for the Gunnison River Basin showing 2002 drought values, Colorado water-quality exceedances, and perelative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample cototal number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees Celsius; E. coli, EschmL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of samples (less than 20) to calculate peless than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado water-quality exceedances; c, chronic water-quality 
63 8-6-2002

9-3-2002

64 8-6-2002

9-4-2002

65 8-6-2002

9-4-2002

66 8-7-200267 8-7-2002

9-4-2002

68 8-7-2002

9-5-2002

69 8-8-2002

9-10-2002

70 8-8-2002

9-11-2002

71 8-7-200272 8-7-200273 8-13-2002

9-23-2002

74 8-13-2002

9-24-2002

75 8-7-2002

9-5-2002

76 8-6-200277 8-6-200278 8-8-200279 8-6-200280 8-5-200281 8-5-200282 8-5-200283 8-5-2002

Site

number in

table 1

and fig. 5

Sampling

date

Conc Q% N Conc Q% N Conc Q% N 

-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 

27 ID 3 -- -- -- -- -- <1 ID 3 26 ID 3 -- -- -- -- -- <1 ID 3 

-- -- -- -- -- -- -- -- -- -- -- 

57c ID 11 -- -- -- -- -- <0.1 ID 7 

10.6 ID 11 -- -- -- -- -- <1 ID 7 

1.5 ID 16 -- -- <0.3 ID 9 <1 ID 4 

<2 ID 16 -- -- <0.3 ID 9 <1 ID 4 

88 ID 2 -- -- 4 ID 2 <1 ID 2 94 ID 2 -- -- 3 ID 2 <1 ID 2 

-- -- -- -- -- 5c ID 14 -- -- -- 

-- -- -- -- -- 7c ID 14 -- -- -- 

350 ID 3 422 <0.01 <2 ID 3 <0.1 ID 3 

36 ID 13 198 <0.01 <2 ID 12 <0.1 ID 13 48 ID 6 -- -- 10 121.4–28.6 27 <1 ID 4 

-- -- -- -- -- 12 150.0–71.4 27 -- -- -- 

16.9 79.1 42 -- -- 6 140.4–46.2 51 <1 23.3–93.3 29 

8.4 22.3–48.8 42 -- -- 8c 171.2–80.8 51 <1 23.3–93.3 29 

14.4 ID 15 -- -- <0.3 ID 4 <0.2 ID 7 

25 ID 15 -- -- -- -- -- <1 ID 7 29 ID 3 -- -- -- -- -- <0.1 ID 2 

1.8 ID 2 -- -- -- -- -- <0.1 ID 2 

-- -- -- -- -- 0.5 ID 5 -- -- -- -- -- -- -- -- -- -- -- -- -- -- 

13.8 ID 2 -- -- -- -- -- <0.1 ID 2 

7.3 ID 9 -- -- -- -- -- <0.1 ID 5 

-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 

Manganese, dissolved, in μg/L Selenium, dissolved, in μg/L Silver, dissolved, in μg/L 

Manganese,

total

recoverable,

in μg/L

Mercury,

dissolved,

in μg/L

Table 14.   Water-quality data for the Gunnison River Basin showing 2002 drought values, Colorado water-quality exceedances, and percentiles relatselected properties and constituents from July through September, 1978–2002.—Continued[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample constituent; N, totadrought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms ate; SiO2, silica; SO4, sulfate; ID, insufficient number of samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations Colorado water-quality exceedances; c, chronic water-quality exceedance]

1 Possible percentile range because of uncensored ties in data.2 Possible percentile range because of censored or recensored ties in data.
Table 15.  Water-quality data for the Dolores River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September 1978–2002.

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances]

Value Q% N

84 8-8-2002 1000 58 7.5 8.3 ID 1

85 8-5-2002 1215 2.5 7.4 8.5 1

80.9–95.7 46

9-26-2002 1130 9.5 8.7 8.5 1

80.9–95.7 46

86 8-5-2002 1415 2.1 8.6 8.6 1

95.7–97.9 46

9-26-2002 1445 9.8 7.8 8.5 1

85.1–93.6 46

87 8-6-2002 850 47 7.9 8.3 ID 2

9-25-2002 1230 88 9.2 8.3 ID 2

88 8-6-2002 1130 9.4 7.8 8.3 ID 7

9-25-2002 1645 49 8.1 8.6 ID 7

Oxygen,

dissolved,

in mg/L

Site number

in table 1

and fig. 5

Sampling

date

Sampling

time

Discharge,

in ft

3

/s

pH, in standard units

84 8-8-2002

85 8-5-2002

9-26-2002

86 8-5-2002

9-26-2002

87 8-6-2002

9-25-2002

88 8-6-2002

9-25-2002

Site number

in table 1

and fig. 5

Sampling

date

Value Q% N Value Q% N

385 93.6 46 17.6 1

75.5–77.6 48

545 28.6 76 24.0 1

76.6–81.8 76

1,790 90.9 76 18.5 15.6 76

9,960 87.5 71 24.5 1

79.2–80.6 71

3,990 81.9 71 23.0 1

61.1–68.1 71

398 93.0 56 13.0 1

43.9–52.6 56

367 80.7 56 10.0 1

14.0–19.3 56

1,700 1

92.9–94.6 55 22.0 153.6–71.4 55

1,130 1

80.4–82.1 55 17.5 10.7 55

Temperature, water, in o Specific conductance, in μS/cm C

84 8-8-2002

85 8-5-2002

9-26-2002

86 8-5-2002

9-26-2002

87 8-6-2002

9-25-2002

88 8-6-2002

9-25-2002

Site number

in table 1

and fig. 5

Sampling

date

160 49 8.7 3.1 15.8 113

180 38 22 4.6 43 108

330 94 22 9.7 217 158

430 65 64 100 1,890 100

440 117 35 31.6 641 159

200 67 6.9 1.1 4.9 115

180 61 6.4 0.88 4.7 134

900 214 89 5.0 54 110

600 155 51 3.2 31 156

Hardness,

total, in mg/L

as CaCO3

Calcium,

dissolved,

in mg/L

Magnesium,

dissolved,

in mg/L

Acid-neutralizing

capacity,

in mg/L as CaCO3

Potassium,

dissolved,

in mg/L

Sodium,

dissolved,

in mg/L

Appendix 95
84 8-8-2002

85 8-5-2002

9-26-2002

86 8-5-2002

9-26-2002

87 8-6-2002

9-25-2002

88 8-6-2002

9-25-2002

Site number

in table 1

and fig. 5

Sampling

date

Conc Q% N Conc Q% N

19.9 ID 1 -- -- --

56 24.0 49 0.20 1

48.0–82.0 49

371 98.0 49 0.24 84.0 49

3,130 98.0 49 0.23 78.0 49

1,050 92.0 49 0.26 80.0 49

3.5 ID 2 -- -- --

2.8 ID 2 -- -- --

9.1 ID 3 -- -- --

6.9 ID 3 -- -- --

Chloride, dissolved, in mg/L Fluoride, dissolved, in mg/L

84 8-8-2002

85 8-5-2002

9-26-2002

86 8-5-2002

9-26-2002

87 8-6-2002

9-25-2002

88 8-6-2002

9-25-2002

Site number

in table 1

and fig. 5

Sampling

date

Conc Q% N Conc Q% N

7.6 ID 1 41 ID 1

4.8 74.0 49 21 2.0 49

7.2 94.0 49 180 82.0 49

1.05 2.0 49 187 80.0 49

7.0 96.0 49 264 92.0 49

8.5 ID 2 108 ID 2

7.7 ID 2 100 ID 2

5.8 ID 3 823 ID 3

7.9 ID 3 480 ID 3

Silica, dissolved, in mg/L as SiO2 Sulfate dissolved, in mg/L as SO4

84 8-8-2002

85 8-5-2002

9-26-2002

86 8-5-2002

9-26-2002

87 8-6-2002

9-25-2002

88 8-6-2002

9-25-2002

Site number

in table 1

and fig. 5

Sampling

date

0.008 <0.013 <0.002 67 <0.04 0.7

<0.04 <0.05 <0.008 60 -- --

-- -- -- 32 -- --

0.11 0.05 0.011 17 <0.1 2

<0.04 0.23 0.009 43 <0.07 3.9

<0.04 0.43 <0.008 210 -- --

0.009 0.25 0.002 5 -- --

<0.04 <0.05 <0.008 30 0.03 3.4

0.014 <0.013 <0.002 13 <0.04 4.3

Nitrogen, nitrite

plus nitrate,

dissolved,

in mg/L as N

Nitrogen, nitrite,

dissolved,

in mg/L as N

Cadmium,

dissolved,

in μg/L

Bacteria,

E. coli ,

in colonies

per 100 mL

Copper,

dissolved,

in μg/L

Nitrogen,

ammonia,

dissolved,

in mg/L as N

Table 15.  Water-quality data for the Dolores River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September 1978–2002.­—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances]

96 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
84 8-8-2002

85 8-5-2002

9-26-2002

86 8-5-2002

9-26-2002

87 8-6-2002

9-25-2002

88 8-6-2002

9-25-2002

Site number

in table 1

and fig. 5

Sampling

date

18 <0.08 8.9 <1 <1

<10 -- -- -- --

-- -- -- -- --

<100 <0.3 21 <4 6

<30 <0.2 26 <2 <2

<10 -- -- -- --

7 -- -- -- --

12 0.08 56 <1 7

5 0.05 42 <1 2

Silver,

dissolved,

in μg/L

Zinc,

dissolved,

in μg/L

Iron,

dissolved,

in μg/L

Lead,

dissolved,

in μg/L

Manganese,

dissolved,

in μg/L

Table 15.  Water-quality data for the Dolores River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September 1978–2002.­—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances]

1

 Possible percentile range because of uncensored ties in data.

Appendix 97
Value Q% N Value Q% 

89 8-5-2002 1400 24 7.2 8.4 ID 2 585 96.0 

9-6-2002 1230 6.8 8.8 8.4 ID 2 626 98.0 

90 7-30-2002 1000 27 8.5 7.6 169.7–78.8 32 74 90.0 91 8-2-2002 1000 11 8.9 8.4 ID 6 337 97.6 

9-19-2002 1430 48 8.2 8.7 ID 6 304 95.2 

92 7-31-2002 1030 74 8.1 6.3 ID 2 496 ID 93 8-1-2002 0945 132 7.8 8.1 ID 2 881 ID 

9-3-2002 1015 119 8.6 8.2 ID 2 898 ID 

94 8-2-2002 1230 4.8 7.3 8.6 ID 11 568 ID 

9-4-2002 1600 1.9 6.7 8.6 ID 11 478 ID 

95 8-8-2002 1430 1.8 7.8 8.5 ID 14 911 ID 

9-4-2002 1030 0.93 8.8 8.4 ID 14 889 ID 

96 8-8-2002 1215 7.9 7.0 8.3 ID 2 239 ID 

9-4-2002 1320 1.1 7.4 8.3 ID 2 302 ID 

97 8-7-2002 0945 5.4 6.9 8.3 169.6–91.3 22 2,360 79.4 

9-18-2002 1045 0.81 8.6 8.2 117.4–65.2 22 4,870 97.1 

98 8-7-2002 1130 16 10.0 8.4 177.1–94.3 34 1,890 94.7 

9-10-2002 1115 9.5 7.2 8.2 15.7–22.9 34 2,680 97.4 

99 8-7-2002 1400 4.5 8.1 8.3 160.3–77.8 62 2,660 92.5 

9-10-2002 1430 13 6.7 8.2 131.7–58.7 62 2,760 93.8 

100 8-1-2002 1445 106 8.0 8.3 ID 3 797 ID 

9-3-2002 1545 86 10.3 8.6 ID 3 783 ID 

101 8-1-2002 1215 128 7.8 8.6 ID 2 834 ID 

9-3-2002 1245 118 10.9 8.5 ID 2 858 ID 

102 8-5-2002 1115 16 7.2 8.5 ID 2 943 ID 

9-6-2002 0945 6.6 10.7 8.5 ID 2 1,480 ID 

Site number

in table 1and fig. 5

Sampling

date

Sampling

time

Oxygen,

dissolved,

in mg/L

Discharge,

in ft3/s

pH, in standard units Specific conductance, i

Table 16.  Water-quality data for the San Juan River Basin showing 2002 drought values, Colorado water-quality exceedances, anpercentiles relative to historical data for selected properties and constituents from July through September,1978–2002.[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-samstituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees Cecoli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of samples 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado water-quality ec, chronic water-quality exceedance]
89 8-5-2002

9-6-2002

90 7-30-200291 8-2-2002

9-19-2002

92 7-31-200293 8-1-2002

9-3-2002

94 8-2-2002

9-4-2002

95 8-8-2002

9-4-2002

96 8-8-2002

9-4-2002

97 8-7-2002

9-18-2002

98 8-7-2002

9-10-2002

99 8-7-2002

9-10-2002

100 8-1-2002

9-3-2002

101 8-1-2002

9-3-2002

102 8-5-2002

9-6-2002

Site number

in table 1and fig. 5

Sampling

date

Value Q% N

26.2 96.1 50 220 71 10.5 3.6 33 129 20.2 62.7 50 250 81 12.3 3.7 36 126 12.0 181.1–90.6 52 30 8.8 2.0 0.60 0.97 -- 

20.2 67.4 42 140 42 7.8 3.2 19.1 164 18.1 48.8 42 130 42 6.1 2.6 13.3 143 11.5 ID 9 240 88 5.3 0.88 3.3 -- 17.2 ID 8 350 113 17.4 6.4 46 197 16.0 ID 8 360 115 17.6 6.5 47 188 23.2 ID 11 230 70 12.8 5.7 37 274 23.4 ID 11 170 46 13.1 2.7 40 199 27.7 97.1 22 400 77 49 1.55 44 180 17.7 47.1 22 390 81 46 1.31 45 177 18.4 ID 2 110 34 5.7 0.91 4.2 68 20.7 ID 2 140 41 8.6 1.15 6.9 78 18.5 122.9–28.6 34 1,200 293 125 5.1 119 242 12.7 8.6 34 2,100 376 292 8.6 486 215 22.0 86.8 37 950 210 102 5.0 94 203 19.0 34.2 37 1,400 305 144 7.1 169 207 27.0 98.8 80 1,300 269 163 7.2 174 298 22.3 188.9–90.1 80 1,300 297 142 7.8 184 235 22.0 ID 3 -- -- -- -- -- -- 19.8 ID 3 -- -- -- -- -- -- 19.0 ID 2 -- -- -- -- -- -- 17.3 ID 2 -- -- -- -- -- -- 24.6 ID 2 200 60 12.3 12.7 113 197 17.3 ID 2 280 86 14.9 21 206 265 

Sodium,

dissolved,

in mg/L

Alkalinity,

laboratory

in mg/L as

CaCO3

Calcium,

dissolved,

in mg/L

Magnesium,

dissolved,

in mg/L

Potassium,

dissolved,

in mg/L

Temperature, water, in oC Hardness,

total, in mg/L

as CaCO3

Table 16.  Water-quality data for the San Juan River Basin showing 2002 drought values, Colorado water-quality exceedances, and percenthistorical data for selected properties and constituents from July through September,1978–2002.­—Continued[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample constitunumber of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees Celsius; E. coli, Escherichia coμg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of samples (less than 20) to calculate percentile; <, less than; sample measurement; values or concentrations in bold type indicate 2002 Colorado water-quality exceedances; c, chronic water-quality exceedance]
89 8-5-2002

9-6-2002

90 7-30-200291 8-2-2002

9-19-2002

92 7-31-200293 8-1-2002

9-3-2002

94 8-2-2002

9-4-2002

95 8-8-2002

9-4-2002

96 8-8-2002

9-4-2002

97 8-7-2002

9-18-2002

98 8-7-2002

9-10-2002

99 8-7-2002

9-10-2002

100 8-1-2002

9-3-2002

101 8-1-2002

9-3-2002

102 8-5-2002

9-6-2002

Site number

in table 1and fig. 5

Sampling

date

Conc Q% N Conc Q% N Conc Q% N Conc 

8.2 ID 2 -- -- -- 16.8 ID 2 155 9.0 ID 2 -- -- -- 16.5 ID 2 167 

0.25 64.4 44 -- -- -- 3.7 88.9 44 10.7 

3.3 ID 6 -- -- -- 4.6 ID 5 14.6 3.2 ID 6 -- -- -- 7.3 ID 5 16.1 

0.69 ID 2 -- -- -- 15.2 ID 2 235 

51 ID 2 -- -- -- 9.5 ID 2 167 52 ID 2 -- -- -- 11.4 ID 2 171 11 ID 1 -- -- -- 10.8 ID 1 28 

12.4 ID 1 -- -- -- 6.1 ID 1 25 

22 ID 14 -- -- -- 14.7 ID 14 276 21 ID 14 -- -- -- 13.8 ID 14 263 

0.5 ID 2 -- -- -- 8.7 ID 2 50 0.9 ID 2 -- -- -- 9.2 ID 2 71 

27 92.0 24 0.31 60.0 24 10.3 129.2–33.3 23 1,190 

71 96.0 24 0.43 92.0 24 7.1 4.2 23 2,800 25 92.1 37 0.33 68.4 37 7.8 5.3 37 901 34 97.4 37 0.45 97.4 37 10.7 21.1 37 1,410 35 84.8 65 0.36 30.8 64 12.5 59.1 65 1,370 35 86.4 65 0.45 89.2 64 12.1 53.0 65 1,440 

-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 

25 ID 2 -- -- -- 18.6 ID 2 236 45 ID 2 -- -- -- 20 ID 2 419 

Chloride, dissolved, in mg/L Fluoride, dissolved, in mg/L S Sulfate, d

ilica, dissolved, in mg/L as SiO2

Table 16.  Water-quality data for the San Juan River Basin showing 2002 drought values, Colorado water-quality exceedances, and percentiles refor selected properties and constituents from July through September,1978–2002.­—Continued[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample constituent; N, and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, microcalcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; valuetype indicate 2002 Colorado water-quality exceedances; c, chronic water-quality exceedance]
89 8-5-2002

9-6-2002

90 7-30-200291 8-2-2002

9-19-2002

92 7-31-200293 8-1-2002

9-3-2002

94 8-2-2002

9-4-2002

95 8-8-2002

9-4-2002

96 8-8-2002

9-4-2002

97 8-7-2002

9-18-2002

98 8-7-2002

9-10-2002

99 8-7-2002

9-10-2002

100 8-1-2002

9-3-2002

101 8-1-2002

9-3-2002

102 8-5-2002

9-6-2002

Site number

in table 1and fig. 5

Sampling

date

Conc Q% N Conc Q% N Conc Q% N

<0.015 ID 2 0.12 -- -- -- <0.013 ID 2 

<0.04 ID 2 0.17 -- -- -- <0.05 ID 2 

<0.015 22.8–58.3 35 0.06 <0.1 24.3–47.8 22 0.143 94.7 37 

<0.04 ID 2 0.39 -- -- -- 0.040 ID 5 

<0.015 ID 2 0.30 -- -- -- <0.013 ID 5 

0.043 ID 1 -- 0.13 ID 1 0.058 ID 1 0.036 ID 2 0.07 -- -- -- 0.086 ID 2 0.028 ID 2 0.08 -- -- -- 0.172 ID 2 

<0.04 ID 1 0.44 -- -- -- 0.070 ID 1 <0.04 ID 1 0.24 -- -- -- <0.05 ID 1 <0.04 ID 2 0.33 -- -- -- 0.060 ID 2 <0.04 ID 2 0.18 -- -- -- 0.140 ID 2 

<0.015 ID 2 0.09 -- -- -- <0.013 ID 2 <0.015 ID 2 0.08 -- -- -- <0.013 ID 2 

<0.04 ID 1 0.53 -- -- -- 2.9 ID 2 

-- -- -- -- -- -- -- -- -- -- 

<0.04 ID 1 0.44 -- -- -- 0.36 ID 2 

-- -- -- -- -- -- -- -- -- -- 

<0.04 ID 2 0.45 -- -- -- 0.020 ID 14 

0.16 ID 2 0.65 -- -- -- 1.49 ID 14 

<0.04 ID 3 -- 0.10 ID 3 <0.05 ID 3 <0.04 ID 3 -- 0.20 ID 3 <0.05 ID 3 <0.04 ID 2 -- 0.14 ID 2 0.060 ID 2 <0.04 ID 2 -- 0.19 ID 2 0.200 ID 2 

0.094 ID 2 0.37 -- -- -- 0.064 ID 2 

<0.015 ID 2 0.32 -- -- -- 0.258 ID 2 

Nitrogen, ammonia, dissolved,

in mg/L as N

Nitrogen, organic plus ammonia, total

recoverable, in mg/L as N

Nitrogen, nitrite plus nitrate

dissolved, in mg/L as N

Nitrogen,

organic plus

ammonia,

dissolved,

in mg/L as N

Table 16.  Water-quality data for the San Juan River Basin showing 2002 drought values, Colorado water-quality exceedances, and perceto historical data for selected properties and constituents from July through September,1978–2002.­—Continued[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample consttotal number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees Celsius; E. coli, Eschermilliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of samples (less than 20) to calculate percentileno drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado water-quality exceedances; c, chronic water-quality exceedance]
89 8-5-2002

9-6-2002

90 7-30-200291 8-2-2002

9-19-2002

92 7-31-200293 8-1-2002

9-3-2002

94 8-2-2002

9-4-2002

95 8-8-2002

9-4-2002

96 8-8-2002

9-4-2002

97 8-7-2002

9-18-2002

98 8-7-2002

9-10-2002

99 8-7-2002

9-10-2002

100 8-1-2002

9-3-2002

101 8-1-2002

9-3-2002

102 8-5-2002

9-6-2002

Site number

in table 1and fig. 5

Sampling

date

Conc Q% N Conc Q% N

0.003 ID 2 0.024 ID 2 <0.007 -- 16 -- 

<0.06 ID 2 <0.06 ID 2 <0.02 -- 5 -- 

<0.004 24.3–65.2 22 <0.004 23.2–51.6 30 <0.007 0.5 -- -- 

0.030 ID 2 0.060 ID 5 0.030 5.3 17 <20 0.059 ID 2 0.171 ID 5 0.046 4.5 83 <20 

-- -- -- 0.021 ID 1 <0.007 0.4 8 50 

0.003 ID 2 0.015 ID 2 <0.007 0.7 38 20 0.006 ID 2 0.023 ID 2 <0.007 1.2 36 <20 0.070 ID 1 0.27 ID 1 0.070 5.8 140 30 

<0.06 ID 1 0.100 ID 1 0.010 3.3 90 20 <0.06 ID 14 <0.06 ID 14 <0.02 3.1 21 <20 <0.06 ID 14 <0.06 ID 14 <0.02 2.7 380 <20 

0.002 ID 2 0.006 ID 2 <0.007 -- 71 -- 0.003 ID 2 0.006 ID 2 <0.007 -- 27 -- 0.050 ID 1 0.22 ID 1 0.050 -- 220 -- 

-- -- -- -- -- -- -- -- 260 -- 

<0.06 ID 1 0.030 ID 1 <0.02 -- 61 -- 

-- -- -- -- -- -- -- -- 540 -- 

<0.06 ID 12 0.060 ID 12 <0.02 7.5 220 <20 

0.030 ID 12 1.66 ID 12 0.020 10 1,100 <20 

-- -- -- 0.008 ID 3 <0.02 -- 3 -- -- -- -- 0.017 ID 3 0.010 1.5 4 -- -- -- -- 0.039 ID 2 0.010 -- 9 -- -- -- -- 0.061 ID 2 0.040 1.5 25 -- 

0.107 ID 2 0.149 ID 2 0.086 -- 28 -- 0.141 ID 2 0.191 ID 2 0.121 -- 100 -- 

Phosphorus,

orthophosphate,

dissolved,

in mg/L as P

Phosphorus, dissolved,

in mg/L as P

Phosphorus, total recoverable, in

mg/L as P

Carbon,

organic,

dissolved,

in mg/L

Bacteria,

E. Coli ,

in colonies per

100 mL

Aluminum,

dissolved,

in μg/L

Table 16.  Water-quality data for the San Juan River Basin showing 2002 drought values, Colorado water-quality exceedances, and percentiles relatiselected properties and constituents from July through September,1978–2002.­—Continued[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample constituent; N, totadrought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concent2002 Colorado water-quality exceedances; c, chronic water-quality exceedance]
89 8-5-2002

9-6-2002

90 7-30-200291 8-2-2002

9-19-2002

92 7-31-200293 8-1-2002

9-3-2002

94 8-2-2002

9-4-2002

95 8-8-2002

9-4-2002

96 8-8-2002

9-4-2002

97 8-7-2002

9-18-2002

98 8-7-2002

9-10-2002

99 8-7-2002

9-10-2002

100 8-1-2002

9-3-2002

101 8-1-2002

9-3-2002

102 8-5-2002

9-6-2002

Site number

in table 1and fig. 5

Sampling

date

-- -- 7 -- -- -- -- -- -- -- <10 -- -- -- -- -- -- -- <10 -- -- -- -- -- 

1.1 -- 28 -- <0.08 -- -- -- 0.8 -- 8 -- <0.08 -- -- -- 5.1 10 1,900c 3,170 <1 953 <0.01 <2 <

1.6 -- 30 -- 0.09 -- -- -- 1.5 -- 17 -- 0.07 -- -- -- 1.2 -- <10 -- 0.07 -- -- -- 0.9 -- <10 -- 0.06 -- -- -- 2.0 -- <10 -- <0.08 -- -- -- 1.8 -- <10 -- <0.08 -- -- -- 

-- -- 23 -- -- -- -- -- -- -- 37 -- -- -- -- -- -- -- 30 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- <10 -- -- -- -- -- -- -- -- -- -- -- -- -- 

5.0 -- 19 -- <0.2 -- -- -- 5.9 -- <10 -- <0.2 -- -- -- 

-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 56 -- -- -- -- -- -- -- 43 -- -- -- -- -- 

Manganese,

total

recoverable,

in μg/L

Mercury,

dissolved,

in μg/L

Selenium,

dissolved,

in μg/L

Iron,

dissolved,

in μg/L

Iron, total

recoverable,

in μg/L

Copper,

dissolved,

in μg/L

S

diss

in 

Copper, total

recoverable,

in μg/L

Lead,

dissolved,

in μg/L

Table 16.  Water-quality data for the San Juan River Basin showing 2002 drought values, Colorado water-quality exceedances, and percentiles redata for selected properties and constituents from July through September,1978–2002.­—Continued[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample constituent; Nand drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrcalcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; valubold type indicate 2002 Colorado water-quality exceedances; c, chronic water-quality exceedance]

1 Possible percentile range because of uncensored ties in data.2 Possible percentile range because of censored or recensored ties in data.
Conc Q% N Value Q% N

103 8-5-2002 1400 12 8.5 61.9 20 8.6 1

81.0–85.7 20

9-5-2002 0940 9.0 10.4 90.5 20 8.5 1

71.4–76.2 20

104 8-13-2002 1200 32 16.8 97.6 41 8.4 1

87.8–92.7 40

9-10-2002 0940 211 6.9 1

7.1–9.5 41 7.9 17.3–19.5 40

105 8-15-2002 1020 58 8.4 ID 19 8.3 ID 19

9-12-2002 1430 72 8 ID 19 8.1 ID 19

106 8-13-2002 0900 86 6.8 1

44.0–48.0 24 7.9 172.0–76.0 24

9-10-2002 1340 458 6.4 1

28.0–40.0 24 7.0 4.0 24

107 8-5-2002 1005 47 7.6 ID 8 7.8 ID 8

9-9-2002 0850 22 7.9 ID 8 7.6 ID 8

108 8-5-2002 1245 553 6.9 10.0 49 7.9 1

87.8–89.8 48

9-9-2002 1220 256 7 1

12.0–14.0 49 9.1 98.0 48

109 8-5-2002 1202 71 7.4 ID 8 8.0 ID 8

9-9-2002 1102 49 7.5 ID 8 9.1 ID 8

110 8-6-2002 1317 16 7.2 ID 8 7.9 ID 8

9-10-2002 1322 11 7.9 ID 8 8.0 ID 8

111 8-8-2002 1000 86 7.5 5.3 74 8.0 1

13.5–20.3 73

9-11-2002 1325 38 9.5 65.3 74 8.5 1

77.0–87.8 73

112 8-8-2002 1150 30 7.1 29.2 23 8.4 1

69.6–73.9 22

9-12-2002 0900 3.4 6.4 12.5 23 8.1 1

26.1–47.8 22

113 8-23-2002 1545 36 7.6 1

8.6–15.7 69 8.2 151.4–65.3 71

9-12-2002 1525 9.5 8.2 1

22.9–25.7 69 8.1 136.1–50.0 71

114 8-23-2002 1440 7.4 12.1 1

91.3–92.8 68 8.8 188.6–90.0 69

9-12-2002 1250 3.8 7.6 1

21.7–23.2 68 7.9 17.1–11.4 69

115 8-6-2002 0940 0.11 13.2 ID 18 8.4 ID 17

116 8-8-2002 1030 113 7.6 36.0 36 7.9 1

7.5–12.5 39

9-3-2002 1050 73 10.8 36.0 36 8.1 1

50.0–65.0 39

117 8-2-2002 1145 86 11 90.2 50 8.4 1

61.5–82.7 51

9-17-2002 1125 192 8.9 58.8 50 8.3 1

36.5–59.6 51

118 9-19-2002 1325 18 11 1

78.1–81.3 31 8.4 163.3–80.0 29

119 8-6-2002 0932 551 7 1

9.7–11.3 61 8.4 185.2–91.8 60

9-10-2002 0852 249 7.3 1

16.1–22.6 61 9.3 98.4 60

120 8-22-2002 1200 1.1 9.1 ID 2 8.1 ID 2

9-16-2002 1100 1.5 9.1 ID 2 8.0 ID 2

121 8-7-2002 1040 29 9.5 ID 15 7.2 ID 16

9-4-2002 1030 10 8.7 ID 15 7.4 ID 16

122 8-7-2002 1255 132 7.3 ID 8 8.1 ID 8

9-11-2002 1150 82 8.6 ID 8 8.5 ID 8

123 9-30-2002 1030 0.74 10.1 ID 1 8.3 ID 1

124 8-6-2002 1147 82 7.4 ID 8 8.1 ID 8

9-10-2002 1152 49 8.1 ID 8 8.3 ID 8

125 8-14-2002 1040 <0.01 7.1 ID 2 8.1 ID 2

9-11-2002 1120 0.09 8 ID 2 7.8 ID 2

Site number

in table 1

and fig. 6

Sampling

date

Sampling

time

Discharge,

in ft

3

/s

Oxygen, dissolved,

in mg/L pH, in standard units

Table 17.  Water-quality data for the South Platte River Basin showing 2002 drought values, Colorado water-quality exceedances,

and percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

104 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
103 8-5-2002

9-5-2002

104 8-13-2002

9-10-2002

105 8-15-2002

9-12-2002

106 8-13-2002

9-10-2002

107 8-5-2002

9-9-2002

108 8-5-2002

9-9-2002

109 8-5-2002

9-9-2002

110 8-6-2002

9-10-2002

111 8-8-2002

9-11-2002

112 8-8-2002

9-12-2002

113 8-23-2002

9-12-2002

114 8-23-2002

9-12-2002

115 8-6-2002

116 8-8-2002

9-3-2002

117 8-2-2002

9-17-2002

118 9-19-2002

119 8-6-2002

9-10-2002

120 8-22-2002

9-16-2002

121 8-7-2002

9-4-2002

122 8-7-2002

9-11-2002

123 9-30-2002

124 8-6-2002

9-10-2002

125 8-14-2002

9-11-2002

Site number

in table 1

and fig. 6

Sampling

date

Value Q% N Value Q% N

1,040 75.7 69 27.5 98.6 68 330 104

1,030 71.4 69 18.0 1

15.9–20.3 68 340 106

992 95.2 41 21.5 1

67.4–68.5 91 270 81

704 66.7 41 18.0 1

21.7–23.9 91 180 54

250 95.7 45 15.0 1

65.7–77.6 66 79 23

277 97.8 45 17.0 1

89.6–92.5 66 91 25

944 88.0 24 18.5 1

17.1–18.6 69 220 64

881 56.0 24 20.5 1

45.7–52.9 69 210 62

23 ID 8 16.0 1

90.3–93.5 30 8 2.3

36 ID 8 14.0 1

80.6–87.1 30 12 3.2

47 94.0 49 18.5 96.0 49 19 5.7

57 98.0 49 17.0 1

86.0–90.0 49 23 6.9

48 ID 8 18.5 1

93.8–96.9 31 19 5.9

57 ID 8 17.0 1

71.9–78.1 31 23 7.0

30 ID 8 20.0 ID 8 10 2.9

36 ID 8 15.5 ID 8 12 3.3

281 15.4 77 19.5 1

64.6–69.6 78 120 34

424 38.5 77 18.5 1

54.4–59.5 78 170 45

376 4.3 22 22.0 83.3 23 150 42

774 52.2 22 17.0 1

25.0–29.2 23 310 73

191 54.2 71 20.5 1

92.0–93.3 74 82 24

394 90.3 71 20.5 1

92.0–93.3 74 180 51

650 37.9 65 25.0 1

91.4–92.9 69 280 75

853 40.9 65 21.0 1

55.7–60.0 69 400 106

1,830 ID 18 22.0 ID 18 770 204

1,510 70.7 40 22.3 75.0 47 540 126

1,660 95.1 40 19.0 1

31.3–37.5 47 590 143

1,710 84.6 51 20.5 1

35.7–38.6 69 600 143

1,570 55.8 51 18.5 1

21.4–25.7 69 520 127

2,080 63.3 29 21.0 1

57.1–62.9 34 720 195

52 91.9 61 18.5 95.2 62 22 6.6

60 98.4 61 16.0 1

60.3–68.3 62 23 7.2

897 ID 2 19.0 ID 2 340 102

783 ID 2 16.0 ID 2 290 84

17 ID 16 15.3 ID 16 5 1.48

19 ID 16 13.0 ID 16 6 1.71

51 ID 8 20.5 ID 8 20 6.0

61 ID 8 17.5 ID 8 21 6.5

595 ID 1 13.0 ID 1 280 80

57 ID 8 19.0 ID 8 21 6.1

67 ID 8 15.5 ID 8 24 7.2

1,450 ID 2 17.5 ID 2 620 135

2,150 ID 2 17.0 ID 2 940 192

Specific conductance,

in μS/cm Temperature, water, in o

C Hardness,

total,

in mg/L

as CaCO3

Calcium,

dissolved, in

mg/L

Table 17.  Water-quality data for the South Platte River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

Appendix 105
103 8-5-2002

9-5-2002

104 8-13-2002

9-10-2002

105 8-15-2002

9-12-2002

106 8-13-2002

9-10-2002

107 8-5-2002

9-9-2002

108 8-5-2002

9-9-2002

109 8-5-2002

9-9-2002

110 8-6-2002

9-10-2002

111 8-8-2002

9-11-2002

112 8-8-2002

9-12-2002

113 8-23-2002

9-12-2002

114 8-23-2002

9-12-2002

115 8-6-2002

116 8-8-2002

9-3-2002

117 8-2-2002

9-17-2002

118 9-19-2002

119 8-6-2002

9-10-2002

120 8-22-2002

9-16-2002

121 8-7-2002

9-4-2002

122 8-7-2002

9-11-2002

123 9-30-2002

124 8-6-2002

9-10-2002

125 8-14-2002

9-11-2002

Site number

in table 1

and fig. 6

Sampling

date

17.3 -- 85 -- 208

17.8 -- 85 -- 214

16.2 10.3 97 -- 176

11.6 6.9 69 -- 128

5.6 2.6 16.1 -- 40

6.6 2.8 16.8 -- 44

13.5 12.2 98 -- 165

13.8 9.4 90 -- 152

0.63 0.30 1.45 -- 10

0.92 0.46 2.0 -- 14

1.12 0.49 2.1 -- 21

1.29 0.57 2.2 -- 27

1.11 0.51 2.1 -- 21

1.3 0.58 2.2 -- 27

0.69 0.51 2.2 -- 13

0.81 0.63 2.3 -- 15

8.6 1.13 9.2 -- 63

15.1 1.39 15.9 -- 69

12.3 1.73 15.7 -- 72

31 3.3 40 -- 110

5.6 -- -- 75 --

12.6 -- 10.6 137 --

22 -- -- 139 --

33 -- 39 165 167

62 -- 125 -- 280

55 -- 116 -- 210

57 -- 138 -- 241

60 9.5 170 224 --

50 8.4 132 244 --

57 -- 196 -- --

1.2 0.47 2.1 -- 25

1.33 0.59 2.1 -- 28

22 2.8 56 -- 247

19.3 3.0 51 -- 192

0.36 -- 0.82 -- 6

0.45 -- 1.04 -- 7

1.16 0.65 2.4 -- 22

1.26 0.84 3.1 -- 25

21 -- 21 -- --

1.26 0.88 3.4 -- 23

1.4 0.89 3.6 -- 27

69 2.3 87 -- 314

112 3.4 157 -- 282

Sodium,

dissolved, in

mg/L

Acidneutralizing

capacity,

in mg/L

as CaCO3

Alkalinity, onsite,

in mg/L

as CaCO3

Magnesium,

dissolved,

in mg/L

Potassium,

dissolved, in

mg/L

Table 17.  Water-quality data for the South Platte River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

106 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
103 8-5-2002

9-5-2002

104 8-13-2002

9-10-2002

105 8-15-2002

9-12-2002

106 8-13-2002

9-10-2002

107 8-5-2002

9-9-2002

108 8-5-2002

9-9-2002

109 8-5-2002

9-9-2002

110 8-6-2002

9-10-2002

111 8-8-2002

9-11-2002

112 8-8-2002

9-12-2002

113 8-23-2002

9-12-2002

114 8-23-2002

9-12-2002

115 8-6-2002

116 8-8-2002

9-3-2002

117 8-2-2002

9-17-2002

118 9-19-2002

119 8-6-2002

9-10-2002

120 8-22-2002

9-16-2002

121 8-7-2002

9-4-2002

122 8-7-2002

9-11-2002

123 9-30-2002

124 8-6-2002

9-10-2002

125 8-14-2002

9-11-2002

Site number

in table 1

and fig. 6

Sampling

date

Conc Q% N Conc Q% N

83 ID 19 21 ID 19

83 ID 19 20 ID 19

92 96.2 25 10.8 80.8 25

58 80.8 25 8.8 34.6 25

11.0 ID 17 7.1 ID 17

16.6 ID 17 7.2 ID 17

93 95.7 22 11.1 69.6 22

82 87.0 22 9.1 13.0 22

0.69 ID 8 -- -- --

1.40 ID 8 -- -- --

0.63 83.3 47 -- -- --

0.58 64.6 47 -- -- --

0.60 ID 8 -- -- --

0.56 ID 8 -- -- --

0.77 ID 8 -- -- --

1.41 ID 8 -- -- --

3.9 53.1 31 -- -- --

4.6 65.6 31 -- -- --

5.4 ID 11 -- -- --

13.8 ID 11 -- -- --

-- -- 31 -- -- --

7.2 84.4 31 9.7 97.6 41

-- -- 26 -- -- --

15.8 59.3 26 9.6 83.3 35

46 ID 16 26 ID 16

80 95.0 39 14.2 95.0 39

86 97.5 39 14.0 1

87.5–92.5 39

98 98.0 49 13.9 76.0 49

84 92.0 49 13.4 74.0 49

-- -- 25 25 74.1 26

0.38 2

1.7–84.7 58 -- -- --

0.38 2

1.7–84.7 58 -- -- --

67 ID 2 18.1 ID 2

58 ID 2 11.6 ID 2

<0.3 ID 10 3.1 ID 10

0.33 ID 10 3.8 ID 10

1.00 ID 8 -- -- --

1.57 ID 8 -- -- --

-- -- -- 15 ID 1

1.89 ID 8 -- -- --

2.1 ID 8 -- -- --

23 ID 2 12.4 ID 2

24 ID 2 10.2 ID 2

Chloride, dissolved, in mg/L

Silica, dissolved,

in mg/L as SiO2

Table 17.  Water-quality data for the South Platte River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

Appendix 107
103 8-5-2002

9-5-2002

104 8-13-2002

9-10-2002

105 8-15-2002

9-12-2002

106 8-13-2002

9-10-2002

107 8-5-2002

9-9-2002

108 8-5-2002

9-9-2002

109 8-5-2002

9-9-2002

110 8-6-2002

9-10-2002

111 8-8-2002

9-11-2002

112 8-8-2002

9-12-2002

113 8-23-2002

9-12-2002

114 8-23-2002

9-12-2002

115 8-6-2002

116 8-8-2002

9-3-2002

117 8-2-2002

9-17-2002

118 9-19-2002

119 8-6-2002

9-10-2002

120 8-22-2002

9-16-2002

121 8-7-2002

9-4-2002

122 8-7-2002

9-11-2002

123 9-30-2002

124 8-6-2002

9-10-2002

125 8-14-2002

9-11-2002

Site number

in table 1

and fig. 6

Sampling

date

Conc Q% N Conc Q% N

185 ID 19 -- 0.020 2

4.8–57.1 20

176 ID 19 -- <0.04 2

4.8–57.1 20

166 96.2 25 -- 0.89c 90.3 30

115 57.7 25 -- 0.51c 77.4 30

56 ID 17 -- <0.04 ID 10

62 ID 17 -- <0.04 ID 10

145 56.5 22 -- 4.65c 80.0 24

139 34.8 22 -- 2.71c 60.0 24

1.6 ID 8 28 <0.015 ID 8

1.9 ID 8 <10 <0.015 ID 8

2.3 85.4 47 38 0.047c ID 18

2.4 85.4 47 39 0.012 ID 18

2.4 ID 8 42 0.030c ID 8

2.4 ID 8 43 0.009 ID 8

1.6 ID 8 34 <0.015 ID 8

1.4 ID 8 29 <0.015 ID 8

69 18.8 31 186 0.010 2

1.5–29.4 67

136 53.1 31 283 <0.015 2

1.5–29.4 67

99 ID 11 241 0.035 1

68.2–72.7 21

255 ID 11 553 0.022 54.5 21

-- -- -- -- <0.04 2

1.4–75.0 71

55 93.8 31 242 <0.04 2

1.4–75.0 71

-- -- -- -- <0.04 2

1.5–27.9 67

299 44.4 26 659 <0.04 2

1.5–27.9 67

642 ID 16 -- 0.020 ID 17

440 52.5 39 -- 1.81c 96.6 28

496 72.5 39 -- 0.90c 89.7 28

562 62.0 49 1290 0.011 ID 17

475 44.0 49 1130 <0.015 11.1 17

-- -- -- -- 0.070 60.9 22

2.5 48.2 55 47 <0.015 2

3.3–53.3 29

2.5 48.2 55 46 <0.015 2

3.3–53.3 29

137 ID 2 -- <0.04 ID 2

126 ID 2 -- <0.04 ID 2

1.4 ID 10 -- <0.015 ID 16

1.9 ID 10 -- <0.015 ID 16

2.5 ID 8 39 0.024c ID 8

2.7 ID 8 18 0.022c ID 8

-- -- -- -- <0.04 ID 1

3.1 ID 8 41 0.016 ID 8

3.0 ID 8 48 <0.015 ID 8

491 ID 2 -- <0.04 ID 2

964 ID 2 -- <0.04 ID 2

Solids,

dissolved,

residue on

evaporation

at 180

o

C,

in mg/L

Sulfate, dissolved,

in mg/L as SO4

Nitrogen, ammonia, dissolved, in

mg/L as N

Table 17.  Water-quality data for the South Platte River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

108 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
103 8-5-2002

9-5-2002

104 8-13-2002

9-10-2002

105 8-15-2002

9-12-2002

106 8-13-2002

9-10-2002

107 8-5-2002

9-9-2002

108 8-5-2002

9-9-2002

109 8-5-2002

9-9-2002

110 8-6-2002

9-10-2002

111 8-8-2002

9-11-2002

112 8-8-2002

9-12-2002

113 8-23-2002

9-12-2002

114 8-23-2002

9-12-2002

115 8-6-2002

116 8-8-2002

9-3-2002

117 8-2-2002

9-17-2002

118 9-19-2002

119 8-6-2002

9-10-2002

120 8-22-2002

9-16-2002

121 8-7-2002

9-4-2002

122 8-7-2002

9-11-2002

123 9-30-2002

124 8-6-2002

9-10-2002

125 8-14-2002

9-11-2002

Site number

in table 1

and fig. 6

Sampling

date

Conc Q% N Conc Q% N

-- -- -- 0.51 54.5 21

-- -- -- 0.29 4.5 21

1.9 92.9 27 -- -- --

1.5 1

82.1--85.7 27 -- -- --

0.10 ID 17 -- -- --

0.10 ID 17 -- -- --

6.0 ID 14 -- -- --

3.9 ID 14 -- -- --

-- -- -- 0.13 ID 8

-- -- -- 0.14 ID 8

-- -- -- 0.29 ID 19

-- -- -- 0.34 ID 19

-- -- -- 0.29 ID 8

-- -- -- 0.32 ID 8

-- -- -- 0.21 ID 8

-- -- -- 0.17 ID 8

-- -- -- 0.44 39.4 32

-- -- -- 0.29 9.1 32

-- -- -- 1.2 ID 6

-- -- -- 0.57 ID 6

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- 0.77 ID 17

-- -- -- 3.3 96.4 27

-- -- -- 2.7 89.3 27

-- -- -- 0.88 ID 18

-- -- -- 0.73 42.1 18

-- -- -- 0.47 10.3 28

-- -- -- 0.21 24.2 61

-- -- -- 0.38 1

54.8–56.5 61

0.21 ID 2 -- -- --

0.26 ID 2 -- -- --

0.10 ID 16 0.10 ID 16

0.06 ID 16 0.10 ID 16

-- -- -- 0.26 ID 8

-- -- -- 0.32 ID 8

-- -- -- 0.18 ID 1

-- -- -- 0.31 ID 8

-- -- -- 0.35 ID 8

0.15 ID 2 -- -- --

0.30 ID 2 -- -- --

Nitrogen, organic plus ammonia,

dissolved, in mg/L as N

Nitrogen, organic plus ammonia, total

recoverable, in mg/L as N

Table 17.  Water-quality data for the South Platte River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

Appendix 109
103 8-5-2002

9-5-2002

104 8-13-2002

9-10-2002

105 8-15-2002

9-12-2002

106 8-13-2002

9-10-2002

107 8-5-2002

9-9-2002

108 8-5-2002

9-9-2002

109 8-5-2002

9-9-2002

110 8-6-2002

9-10-2002

111 8-8-2002

9-11-2002

112 8-8-2002

9-12-2002

113 8-23-2002

9-12-2002

114 8-23-2002

9-12-2002

115 8-6-2002

116 8-8-2002

9-3-2002

117 8-2-2002

9-17-2002

118 9-19-2002

119 8-6-2002

9-10-2002

120 8-22-2002

9-16-2002

121 8-7-2002

9-4-2002

122 8-7-2002

9-11-2002

123 9-30-2002

124 8-6-2002

9-10-2002

125 8-14-2002

9-11-2002

Site number

in table 1

and fig. 6

Sampling

date

Conc Q% N Conc Q% N

3.0 71.4 20 0.046 71.4 20

3.7 95.2 20 0.018 14.3 20

9.7 96.8 30 0.344 85.7 27

5.4 90.3 30 0.219 82.1 27

0.150 ID 17 <0.008 ID 10

0.140 ID 17 <0.008 ID 10

5.3 76.0 24 1.21 96.0 24

4.8 64.0 24 0.638 72.0 24

0.127 ID 8 -- -- --

0.098 ID 8 -- -- --

0.034 2

2.0–90.0 49 -- -- --

0.014 2

2.0–90.0 49 -- -- --

0.029 ID 8 -- -- --

0.014 ID 8 -- -- --

0.094 ID 8 -- -- --

0.072 ID 8 -- -- --

0.085 35.6 58 -- -- --

0.128 55.9 58 -- -- --

1.11 52.4 20 -- -- --

3.7 95.2 20 -- -- --

0.016 3.2 61 <0.008 2

1.5–95.5 65

0.107 32.3 61 0.007 2

1.5–95.5 65

0.392 29.3 57 0.010 1

11.9–19.4 66

0.636 48.3 57 0.032 52.2 66

12.4 ID 17 0.146 ID 17

6.0 82.9 40 0.212 93.1 28

7.4 95.1 40 0.288 96.6 28

3.4 51.0 50 0.046 ID 17

3.8 56.9 50 0.024 55.6 17

3.6 91.7 23 0.043 ID 12

<0.013 2

1.7–93.2 58 -- -- --

<0.013 2

1.7–93.2 58 -- -- --

1.03 ID 2 0.015 ID 2

0.650 ID 2 0.005 ID 2

0.190 ID 16 <0.002 ID 16

0.133 ID 16 <0.002 ID 16

0.091 ID 8 -- -- --

0.149 ID 8 -- -- --

0.060 ID 1 <0.008 ID 1

0.363 ID 8 -- -- --

0.546 ID 8 -- -- --

0.880 ID 2 0.004 ID 2

0.990 ID 2 0.020 ID 2

Nitrogen, nitrite plus nitrate, dissolved, in

mg/L as N

Nitrogen, nitrite, dissolved, in mg/L

as N

Table 17.  Water-quality data for the South Platte River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

110 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
103 8-5-2002

9-5-2002

104 8-13-2002

9-10-2002

105 8-15-2002

9-12-2002

106 8-13-2002

9-10-2002

107 8-5-2002

9-9-2002

108 8-5-2002

9-9-2002

109 8-5-2002

9-9-2002

110 8-6-2002

9-10-2002

111 8-8-2002

9-11-2002

112 8-8-2002

9-12-2002

113 8-23-2002

9-12-2002

114 8-23-2002

9-12-2002

115 8-6-2002

116 8-8-2002

9-3-2002

117 8-2-2002

9-17-2002

118 9-19-2002

119 8-6-2002

9-10-2002

120 8-22-2002

9-16-2002

121 8-7-2002

9-4-2002

122 8-7-2002

9-11-2002

123 9-30-2002

124 8-6-2002

9-10-2002

125 8-14-2002

9-11-2002

Site number

in table 1

and fig. 6

Sampling

date

Conc Q% N Conc Q% N

-- -- -- 0.28 1

57.1–71.4 20

-- -- -- 0.22 1

14.3–19.0 20

1.56 96.4 27 1.6 90.3 30

0.86 85.7 27 1.12 87.1 30

<0.06 ID 17 <0.06 ID 17

<0.06 ID 17 <0.06 ID 17

2.2 76.0 24 2.2 73.9 22

1.11 36.0 24 1.47 34.8 22

0.005 ID 8 0.008 ID 8

0.004 ID 8 0.011 ID 8

0.007 2

2.1–42.6 46 0.023 56.0 49

0.005 2

2.1–42.6 46 0.024 58.0 49

0.009 ID 8 0.021 ID 8

0.004 ID 8 0.020 ID 8

0.009 ID 8 0.023 ID 8

0.008 ID 8 0.021 ID 8

0.009 2

1.6–46.0 62 0.077 ID 8

0.017 2

1.6–46.0 62 0.037 ID 8

0.184 ID 13 0.48 ID 6

0.46 ID 13 0.47 ID 6

<0.06 2

1.7–95.0 59 -- -- --

<0.06 2

1.7–95.0 59 -- -- --

0.11 1

80.7–82.5 56 -- -- --

0.10 1

77.2–78.9 56 -- -- --

-- -- -- 0.071 ID 17

-- -- -- 0.79 85.7 27

-- -- -- 0.81 89.3 27

0.049 6.7 44 0.130 ID 18

0.19 1

42.2–46.7 44 0.28 ID 18

-- -- -- 0.024 17.9 27

0.004 2

1.9–57.4 53 0.015 150.8–52.5 58

0.003 2

1.9–57.4 53 0.015 150.8–52.5 58

0.04 ID 2 0.040 ID 2

<0.06 ID 2 0.040 ID 2

<0.004 ID 16 0.007 ID 16

0.002 ID 16 0.006 ID 16

0.03 ID 8 0.047 ID 8

0.061 ID 8 0.084 ID 8

-- -- -- 0.012 ID 1

0.138 ID 8 0.167 ID 8

0.098 ID 8 0.130 ID 8

<0.06 ID 2 <0.06 ID 2

<0.06 ID 2 0.030 ID 2

Phosphorus, dissolved, in mg/L

as P

Phosphorus, total recoverable, in mg/L

as P

Table 17.  Water-quality data for the South Platte River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

Appendix 111
103 8-5-2002

9-5-2002

104 8-13-2002

9-10-2002

105 8-15-2002

9-12-2002

106 8-13-2002

9-10-2002

107 8-5-2002

9-9-2002

108 8-5-2002

9-9-2002

109 8-5-2002

9-9-2002

110 8-6-2002

9-10-2002

111 8-8-2002

9-11-2002

112 8-8-2002

9-12-2002

113 8-23-2002

9-12-2002

114 8-23-2002

9-12-2002

115 8-6-2002

116 8-8-2002

9-3-2002

117 8-2-2002

9-17-2002

118 9-19-2002

119 8-6-2002

9-10-2002

120 8-22-2002

9-16-2002

121 8-7-2002

9-4-2002

122 8-7-2002

9-11-2002

123 9-30-2002

124 8-6-2002

9-10-2002

125 8-14-2002

9-11-2002

Site number

in table 1

and fig. 6

Sampling

date

Conc Q% N Conc Q% N

0.220 1

57.1–61.9 20 4.6 ID 17

0.190 28.6 20 2.9 ID 17

1.5 96.8 30 -- -- --

0.800 83.9 30 25 92.6 26

<0.02 ID 10 -- -- --

<0.02 ID 10 1.4 ID 9

2.0 80.0 24 -- -- --

1.0 1

28.0–32.0 24 11.7 ID 10

<0.007 ID 8 -- -- --

<0.007 ID 8 -- -- --

<0.007 2

4.8–81.0 20 -- -- --

<0.007 2

4.8–81.0 20 -- -- --

<0.007 ID 8 -- -- --

<0.007 ID 8 -- -- --

<0.007 ID 8 -- -- --

<0.007 ID 8 -- -- --

<0.007 2

2.4–63.4 40 -- -- --

0.007 2

2.4–63.4 40 -- -- --

0.162 ID 11 -- -- --

0.414 ID 11 -- -- --

<0.02 2

2.6–87.2 38 -- -- --

<0.02 2

2.6–87.2 38 -- -- --

0.100 1

88.9–91.7 35 -- -- --

0.080 83.3 35 -- -- --

0.040 ID 17 5.3 ID 16

0.540 88.6 34 6.9 96.4 27

0.550 91.4 34 4.3 1

32.1–35.7 27

0.037 8.3 23 -- -- --

0.189 58.3 23 4.3 ID 1

<0.02 ID 16 3.9 ID 6

<0.007 2

3.1–81.3 31 -- -- --

<0.007 2

3.1–81.3 31 -- -- --

0.020 ID 2 2.7 ID 2

<0.02 ID 2 3.3 ID 2

<0.007 ID 16 1.5 ID 10

<0.007 ID 16 1.5 ID 10

0.020 ID 8 -- -- --

0.048 ID 8 -- -- --

0.010 ID 1 2.7 ID 1

0.125 ID 8 -- -- --

0.085 ID 8 -- -- --

<0.02 ID 2 -- -- --

<0.02 ID 2 -- -- --

Carbon, organic, dissolved, in mg/L Phosphorus, orthophosphate, dissolved, in

mg/L as P

Table 17.  Water-quality data for the South Platte River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

112 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
103 8-5-2002

9-5-2002

104 8-13-2002

9-10-2002

105 8-15-2002

9-12-2002

106 8-13-2002

9-10-2002

107 8-5-2002

9-9-2002

108 8-5-2002

9-9-2002

109 8-5-2002

9-9-2002

110 8-6-2002

9-10-2002

111 8-8-2002

9-11-2002

112 8-8-2002

9-12-2002

113 8-23-2002

9-12-2002

114 8-23-2002

9-12-2002

115 8-6-2002

116 8-8-2002

9-3-2002

117 8-2-2002

9-17-2002

118 9-19-2002

119 8-6-2002

9-10-2002

120 8-22-2002

9-16-2002

121 8-7-2002

9-4-2002

122 8-7-2002

9-11-2002

123 9-30-2002

124 8-6-2002

9-10-2002

125 8-14-2002

9-11-2002

Site number

in table 1

and fig. 6

Sampling

date

Conc Q% N

1.2 ID 16 -- -- --

0.3 ID 16 -- -- --

-- -- -- -- -- --

-- -- -- 10 -- 0.08

-- -- -- 20 -- 0.21

-- -- -- 20 -- 0.28

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- <0.2 --

-- -- -- -- 0.1 --

-- -- -- -- 0.2 --

-- -- -- -- 0.3 --

-- -- -- -- 0.3 --

-- -- -- -- 0.3 --

-- -- -- -- 0.1 --

-- -- -- -- 0.1 --

-- -- -- -- 0.6 --

-- -- -- -- 0.6 --

-- -- -- -- 0.7 --

-- -- -- -- 1.0 --

-- -- -- -- -- --

-- -- -- 3 1.0 <0.1

-- -- -- -- -- --

-- -- -- 1 <2 0.10

0.4 ID 16 -- -- --

4.0 88.9 26 -- -- --

1.2 25.9 26 -- -- --

-- -- -- -- -- 0.10

-- -- -- -- -- <0.1

-- -- -- <20 -- 0.03

-- -- -- -- 0.3 --

-- -- -- -- 0.4 --

-- -- -- <20 -- <0.04

-- -- -- <20 -- <0.04

0.3 ID 9 -- -- --

0.2 ID 9 -- -- --

-- -- -- -- 0.2 --

-- -- -- -- 0.3 --

-- -- -- <20 -- <0.04

-- -- -- -- 0.2 --

-- -- -- -- 0.3 --

-- -- -- -- -- --

-- -- -- -- -- --

Carbon, organic, total recoverable, in

mg/L Aluminum,

dissolved,

in μg/L

Arsenic,

dissolved,

in μg/L

Cadmium,

dissolved,

in μg/L

Appendix 113

Table 17.  Water-quality data for the South Platte River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]
103 8-5-2002

9-5-2002

104 8-13-2002

9-10-2002

105 8-15-2002

9-12-2002

106 8-13-2002

9-10-2002

107 8-5-2002

9-9-2002

108 8-5-2002

9-9-2002

109 8-5-2002

9-9-2002

110 8-6-2002

9-10-2002

111 8-8-2002

9-11-2002

112 8-8-2002

9-12-2002

113 8-23-2002

9-12-2002

114 8-23-2002

9-12-2002

115 8-6-2002

116 8-8-2002

9-3-2002

117 8-2-2002

9-17-2002

118 9-19-2002

119 8-6-2002

9-10-2002

120 8-22-2002

9-16-2002

121 8-7-2002

9-4-2002

122 8-7-2002

9-11-2002

123 9-30-2002

124 8-6-2002

9-10-2002

125 8-14-2002

9-11-2002

Site number

in table 1

and fig. 6

Sampling

date

Conc Q% N Conc Q% N

-- -- -- <10 ID 19

-- -- -- 8 ID 19

-- -- -- 35 70.4 26

4.4 ID 8 44 81.5 26

4.3 ID 8 19 ID 18

4.1 ID 8 25 ID 18

-- -- -- 65 ID 18

-- -- -- 41 ID 18

0.6 ID 8 129 ID 8

0.6 ID 8 140 ID 8

0.6 ID 18 86 67.4 45

0.5 ID 18 36 6.5 45

0.6 ID 8 65 ID 8

0.5 ID 8 45 ID 8

1.9ac ID 8 64 ID 8

0.5 ID 8 83 ID 8

1.1 1

35.7–40.5 41 8 23.6–14.3 27

2.2 83.3 41 26 53.6 27

1.6 2

4.8–47.6 20 6 ID 6

2.5 71.4 20 18 ID 6

1.3 31.8 43 18 8.6 34

1.1 27.3 43 32 25.7 34

1.8 1

59.6–63.8 46 24 27.6 28

2.2 80.9 46 12 13.8 28

-- -- -- <10 ID 16

-- -- -- <10 2

2.5–75.0 39

-- -- -- 20 1

77.5–80.0 39

3.3 ID 16 <10 2

2.0–64.0 49

3.5 ID 16 5 2

2.0–64.0 49

3.7 ID 15 <10 ID 18

0.6 2

2.4–95.2 41 36 65.5 57

0.5 2

2.4–95.2 41 13 11.7–3.4 57

1.8 ID 2 28 ID 2

1.2 ID 2 21 ID 2

-- -- -- 68 ID 13

-- -- -- 111 ID 13

1.3 ID 7 53 ID 8

1.7 ID 7 40 ID 8

1.3 ID 1 20 ID 1

0.8 ID 8 44 ID 8

0.7 ID 8 26 ID 8

-- -- -- <10 ID 2

-- -- -- <10 ID 2

Copper, dissolved, in μg/L Iron, dissolved, in μg/L

114 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002

Table 17.  Water-quality data for the South Platte River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]
103 8-5-2002

9-5-2002

104 8-13-2002

9-10-2002

105 8-15-2002

9-12-2002

106 8-13-2002

9-10-2002

107 8-5-2002

9-9-2002

108 8-5-2002

9-9-2002

109 8-5-2002

9-9-2002

110 8-6-2002

9-10-2002

111 8-8-2002

9-11-2002

112 8-8-2002

9-12-2002

113 8-23-2002

9-12-2002

114 8-23-2002

9-12-2002

115 8-6-2002

116 8-8-2002

9-3-2002

117 8-2-2002

9-17-2002

118 9-19-2002

119 8-6-2002

9-10-2002

120 8-22-2002

9-16-2002

121 8-7-2002

9-4-2002

122 8-7-2002

9-11-2002

123 9-30-2002

124 8-6-2002

9-10-2002

125 8-14-2002

9-11-2002

Site number

in table 1

and fig. 6

Sampling

date

Conc Q% N Conc Q% N

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- 0.25 ID 8

-- -- -- 0.23 ID 8

-- -- -- 0.23 ID 8

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- <0.08 ID 8

-- -- -- 0.10 ID 8

-- -- -- <0.08 ID 18

-- -- -- <0.08 ID 18

-- -- -- <0.08 ID 8

-- -- -- <0.08 ID 8

-- -- -- 0.14 ID 8

-- -- -- 0.07 ID 8

-- -- -- 0.10 ID 19

-- -- -- 0.11 ID 19

-- -- -- 0.06 ID 11

-- -- -- 0.11 ID 11

200 1

52.0–56.0 49 -- -- --

210 1

58.0–62.0 49 <1 ID 14

240 1

15.4–21.2 51 -- -- --

250 1

23.1–25.0 51 <1 ID 15

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- 0.06 ID 16

-- -- -- 0.17 ID 16

-- -- -- <0.08 ID 15

-- -- -- 0.04 2

2.9–94.1 33

-- -- -- 0.05 2

2.9–94.1 33

-- -- -- 0.04 ID 2

-- -- -- 0.05 ID 2

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- 0.07 ID 8

-- -- -- 0.08 ID 8

-- -- -- 0.04 ID 1

-- -- -- <0.08 ID 8

-- -- -- 0.05 ID 8

-- -- -- -- -- --

-- -- -- -- -- --

Iron, total recoverable, in μg/L Lead, dissolved, in μg/L

Appendix 115

Table 17.  Water-quality data for the South Platte River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]
103 8-5-2002

9-5-2002

104 8-13-2002

9-10-2002

105 8-15-2002

9-12-2002

106 8-13-2002

9-10-2002

107 8-5-2002

9-9-2002

108 8-5-2002

9-9-2002

109 8-5-2002

9-9-2002

110 8-6-2002

9-10-2002

111 8-8-2002

9-11-2002

112 8-8-2002

9-12-2002

113 8-23-2002

9-12-2002

114 8-23-2002

9-12-2002

115 8-6-2002

116 8-8-2002

9-3-2002

117 8-2-2002

9-17-2002

118 9-19-2002

119 8-6-2002

9-10-2002

120 8-22-2002

9-16-2002

121 8-7-2002

9-4-2002

122 8-7-2002

9-11-2002

123 9-30-2002

124 8-6-2002

9-10-2002

125 8-14-2002

9-11-2002

Site number

in table 1

and fig. 6

Sampling

date

Conc Q% N Conc Q% N

18.9 ID 19 -- -- -- --

13.7 ID 19 -- -- -- --

-- -- -- -- -- -- --

46 50.0 25 -- -- -- --

21 ID 18 -- -- -- --

36 ID 18 -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

3.4 ID 8 <0.01 0.10 ID 8

6.8 ID 8 <0.01 0.21 ID 8

2.0 2

2.0–88.0 49 <0.01 0.16 ID 18

0.7 2

2.0–88.0 49 <0.01 0.32 ID 18

1.5 ID 8 <0.01 0.15 ID 8

1.7 ID 8 <0.01 0.31 ID 8

3.4 ID 8 <0.01 0.11 ID 8

4.7 ID 8 <0.01 0.19 ID 8

9.1 25.0 31 <0.01 0.77 ID 19

16.5 53.1 31 <0.01 1.68 ID 19

19.6 ID 6 <0.01 1.11 ID 11

47 ID 6 <0.01 2.7 ID 11

-- -- -- -- -- -- --

-- -- -- <0.01 1.2 ID 14

-- -- -- -- -- -- 15

-- -- -- <0.01 1.5 ID 15

10.2 ID 16 -- -- -- --

177 97.5 39 -- -- -- --

167 95.0 39 -- -- -- --

40 98.0 49 -- 4.2 ID 16

23 88.0 49 -- 6.3 ID 16

7.9 ID 18 -- -- -- --

1.5 2

1.6–98.4 61 <0.01 0.16 22.9–97.1 34

0.8 2

1.6–98.4 61 <0.01 0.31 22.9–97.1 34

69 ID 2 -- -- -- --

63 ID 2 -- -- -- --

2.9 ID 13 -- -- -- --

4.0 ID 13 -- -- -- --

3.0 ID 8 <0.01 0.16 ID 8

5.1 ID 8 <0.01 0.36 ID 8

14.3 ID 1 -- -- -- --

2.9 ID 8 <0.01 0.22 ID 8

2.9 ID 8 0.01 0.40 ID 8

-- -- -- -- -- -- --

-- -- -- -- -- -- --

Mercury,

dissolved,

in μg/L

Manganese, dissolved, in μg/L Nickel, dissolved, in μg/L

116 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002

Table 17.  Water-quality data for the South Platte River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]
103 8-5-2002

9-5-2002

104 8-13-2002

9-10-2002

105 8-15-2002

9-12-2002

106 8-13-2002

9-10-2002

107 8-5-2002

9-9-2002

108 8-5-2002

9-9-2002

109 8-5-2002

9-9-2002

110 8-6-2002

9-10-2002

111 8-8-2002

9-11-2002

112 8-8-2002

9-12-2002

113 8-23-2002

9-12-2002

114 8-23-2002

9-12-2002

115 8-6-2002

116 8-8-2002

9-3-2002

117 8-2-2002

9-17-2002

118 9-19-2002

119 8-6-2002

9-10-2002

120 8-22-2002

9-16-2002

121 8-7-2002

9-4-2002

122 8-7-2002

9-11-2002

123 9-30-2002

124 8-6-2002

9-10-2002

125 8-14-2002

9-11-2002

Site number

in table 1

and fig. 6

Sampling

date

Conc Q% N

-- -- -- --

-- -- -- --

-- -- -- --

<1 ID 5 18

<1 ID 6 33

<1 ID 6 41

-- -- -- --

-- -- -- --

<1 ID 8 --

<1 ID 8 --

<1 ID 18 --

<1 ID 18 --

<1 ID 8 --

<1 ID 8 --

<1 ID 8 --

<1 ID 8 --

<1 2

2.4–97.6 40 --

<1 2

2.4–97.6 40 --

<1 ID 16 --

<1 ID 16 --

<0.1 2

2.7–86.5 36 --

<0.1 2

2.7–86.5 36 2

<0.1 2

2.5–95.0 39 --

<0.1 2

2.5–95.0 39 3

-- -- -- --

-- -- -- --

-- -- -- --

<1 ID 16 3

<1 ID 16 24

<1 ID 18 4

<1 2

3.8–76.9 25 --

<1 2

3.8–76.9 25 --

<1 ID 2 15

<1 ID 2 4

-- -- -- --

-- -- -- --

<1 ID 8 --

<1 ID 8 --

<1 ID 1 <1

<1 ID 8 --

<1 ID 8 --

-- -- -- --

-- -- -- --

Zinc, dissolved,

in μg/L

Silver, dissolved, in μg/L

Appendix 117

Table 17.  Water-quality data for the South Platte River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

1

 Possible percentile range because of uncensored ties in data.

2

 Possible percentile range because of censored or recensored ties in data.
Conc Q% N

126 7-19-2002 1640 126 6.8 ID 8

8-26-2002 1340 139 7.5 ID 8

127 7-31-2002 1215 171 8.4 ID 8

8-26-2002 1000 175 8.3 ID 8

128 7-31-2002 1345 139 12.9 96.1 50

8-26-2002 1115 150 9.4 70.6 50

129 7-31-2002 915 165 7.6 ID 16

8-26-2002 1300 125 11.0 ID 16

130 7-22-2002 1505 298 10.2 93.3 29

8-27-2002 1110 9.5 6.4 3.3 29

131 7-22-2002 1315 185 9.8 ID 15

8-27-2002 1225 4.4 8.7 ID 15

132 8-21-2002 915 2.9 7.9 1

29.7–47.3 73

133 8-21-2002 1100 2.8 8.0 1

41.5–47.2 52

134 8-21-2002 1230 4.7 8.3 ID 11

135 8-20-2002 1230 6.6 7.6 1

71.2–76.3 58

136 8-20-2002 1035 7.9 6.9 1

23.9–26.1 87

137 8-20-2002 1630 66 7.1 1

56.8–59.3 80

138 8-20-2002 1500 84 6.6 ID 19

139 8-19-2002 1020 73 7.1 ID 12

140 8-19-2002 1300 45 7.1 1

61.3–64.5 30

141 7-24-2002 1130 276 7.5 75.8 32

8-27-2002 1430 103 8.4 1

87.9–90.9 32

142 7-23-2002 1100 23 8.4 ID 13

8-28-2002 1415 5.7 8.9 ID 13

143 7-23-2002 1600 20 8.2 ID 2

8-28-2002 1250 6.4 9.0 ID 2

144 7-23-2002 1245 28 8.2 ID 14

9-4-2002 1515 12 7.3 ID 14

145 7-23-2002 1115 10 8.4 1

72.4–75.9 28

9-4-2002 1045 13 9.0 89.7 28

146 8-28-2002 1400 1.9 6.9 ID 3

147 9-4-2002 1225 0.21 5.8 ID 1

148 9-4-2002 0915 5.8 7.8 ID 4

Site

number in

table 1

and fig. 7

Sampling

date

Sampling

time

Discharge,

in ft

3

/s

Oxygen, dissolved, in mg/L

Table 18.  Water-quality data for the Arkansas River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

118 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
126 7-19-2002

8-26-2002

127 7-31-2002

8-26-2002

128 7-31-2002

8-26-2002

129 7-31-2002

8-26-2002

130 7-22-2002

8-27-2002

131 7-22-2002

8-27-2002

132 8-21-2002

133 8-21-2002

134 8-21-2002

135 8-20-2002

136 8-20-2002

137 8-20-2002

138 8-20-2002

139 8-19-2002

140 8-19-2002

141 7-24-2002

8-27-2002

142 7-23-2002

8-28-2002

143 7-23-2002

8-28-2002

144 7-23-2002

9-4-2002

145 7-23-2002

9-4-2002

146 8-28-2002

147 9-4-2002

148 9-4-2002

Site

number in

table 1

and fig. 7

Sampling

date

Value Q% N Value Q% N

8.3 ID 9 129 65.2 45

7.4 ID 9 105 1

39.1–41.3 45

8.5 ID 9 244 48.0 24

8.2 ID 9 239 44.0 24

8.7 1

79.3–82.8 57 472 181.1–82.4 73

8.5 1

58.6–63.8 57 520 91.9 73

8.2 ID 16 559 ID 16

8.6 ID 16 593 ID 16

8.1 1

36.4–51.5 32 606 95.1 40

8.1 1

36.4–51.5 32 657 97.6 40

8.7 ID 17 651 90.5 20

8.0 ID 17 1,780 95.2 20

8.4 1

84.6–-94.9 77 558 99.3 146

8.3 1

37.7–45.3 52 467 98.9 94

8.6 ID 12 445 95.7 46

8.4 1

52.5–76.3 58 902 98.3 59

8.2 1

51.1–68.5 91 1,040 99.0 195

7.9 1

57.1–75.0 83 751 53.4 102

8.4 1

90.9–95.5 21 788 65.1 108

8.2 ID 12 995 38.5 25

8.4 1

84.4–96.9 31 1,100 156.7–57.9 170

8.1 1

34.3–48.6 34 912 89.1 63

8.2 1

51.4–82.9 34 1,220 96.9 63

8.4 ID 14 1,080 81.8 32

8.2 ID 14 1,900 97.0 32

8.5 ID 2 2,170 ID 2

8.2 ID 2 2,360 ID 2

8.2 ID 16 2,310 77.3 21

8.2 ID 16 2,460 86.4 21

8.1 1

23.3–50.0 29 3,320 182.4–83.0 181

8.1 1

23.3–50.0 29 3,300 180.2–81.3 181

8.7 ID 6 1,070 99.0 95

8.0 ID 1 409 ID 1

8.0 ID 5 3,680 88.9 80

pH, in standard units Specific conductance, in μS/cm

Table 18.  Water-quality data for the Arkansas River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

Appendix 119
126 7-19-2002

8-26-2002

127 7-31-2002

8-26-2002

128 7-31-2002

8-26-2002

129 7-31-2002

8-26-2002

130 7-22-2002

8-27-2002

131 7-22-2002

8-27-2002

132 8-21-2002

133 8-21-2002

134 8-21-2002

135 8-20-2002

136 8-20-2002

137 8-20-2002

138 8-20-2002

139 8-19-2002

140 8-19-2002

141 7-24-2002

8-27-2002

142 7-23-2002

8-28-2002

143 7-23-2002

8-28-2002

144 7-23-2002

9-4-2002

145 7-23-2002

9-4-2002

146 8-28-2002

147 9-4-2002

148 9-4-2002

Site

number in

table 1

and fig. 7

Sampling

date

Value Q% N

21.5 96.3 26 55 14.5 4.58

17.0 92.6 26 46 12.6 3.47

22.5 ID 15 100 29.2 6.72

19.5 ID 15 95 27.6 6.33

27.0 98.7 74 190 52.6 14.8

21.0 1

57.3–60.0 74 200 55.7 15.5

21.0 ID 16 -- -- --

24.0 ID 16 -- -- --

19.0 1

21.7–34.8 45 260 70.7 19.6

20.5 1

63–71.7 45 -- -- --

23.0 85.7 20 270 72.4 21.6

21.0 1

38.1–47.6 20 -- -- --

15.5 1

69.7–73.5 154 200 59.1 12.7

20.5 1

58.8–61.9 96 110 29.4 9.47

21.0 1

53.1–59.2 48 150 47.8 8.23

21.5 1

36.1–39.3 60 330 95.1 21.4

23.0 1

72.2–77.1 204 370 104 27.7

23.5 1

86.9–90.7 106 190 45.7 18.9

27.5 1

90.8–95.4 108 190 48.3 17.9

20.5 1

34.6–38.5 25 280 72 24.6

26.5 1

71.7–76.1 158 330 85.3 27.5

25.0 1

91.3–92.8 68 330 80.5 31.9

24.5 1

87.0–89.9 68 -- -- --

24.5 ID 18 430 108 38.7

31.5 ID 18 -- -- --

30.5 ID 2 810 192 79.2

26.0 ID 2 -- -- --

29.5 89.7 77 960 250 82.8

32.0 94.9 77 -- -- --

26.5 1

73.4–73.9 183 1,300 325 125

22.5 1

38.0–39.1 183 -- -- --

23.5 1

89.0–90.1 90 140 29.4 17.4

22.5 27.3 32 170 51.9 9.93

19.0 1

16.5–20.3 78 1,400 320 156

Calcium,

dissolved, in

mg/L

Magnesium,

dissolved, in mg/L

Temperature, water, in o

C

Hardness, total,

in mg/L as CaCO3

Table 18.  Water-quality data for the Arkansas River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees

 Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

120 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
126 7-19-2002

8-26-2002

127 7-31-2002

8-26-2002

128 7-31-2002

8-26-2002

129 7-31-2002

8-26-2002

130 7-22-2002

8-27-2002

131 7-22-2002

8-27-2002

132 8-21-2002

133 8-21-2002

134 8-21-2002

135 8-20-2002

136 8-20-2002

137 8-20-2002

138 8-20-2002

139 8-19-2002

140 8-19-2002

141 7-24-2002

8-27-2002

142 7-23-2002

8-28-2002

143 7-23-2002

8-28-2002

144 7-23-2002

9-4-2002

145 7-23-2002

9-4-2002

146 8-28-2002

147 9-4-2002

148 9-4-2002

Site

number in

table 1

and fig. 7

Sampling

date

Conc Q% N

0.76 3.2 42 -- -- --

0.68 2.5 34 -- -- --

1.6 10.2 88 7.2 ID 1

1.6 9.4 84 -- -- --

2.8 27 127 9.8 95.0 39

2.8 30 131 -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

3.0 30 -- 10.2 ID 16

-- -- -- -- -- --

3.0 35 -- 11.8 ID 9

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

4.3 59 -- 24 ID 10

-- -- -- -- -- --

4.0 73 -- 25 ID 7

-- -- -- -- -- --

6.6 210 -- 79 ID 1

-- -- -- -- -- --

5.0 174 -- 53 ID 2

-- -- -- -- -- --

4.8 344 -- 90 ID 7

-- -- -- -- -- --

3.3 174 -- 110 ID 4

4.5 12.8 -- 2.89 ID 1

7.0 381 -- 95 ID 2

Chloride, dissolved, in mg/L

Potassium,

dissolved, in

mg/L

Sodium,

dissolved, in

mg/L

Acidneutralizing

capacity, in

mg/L as CaCO3

Table 18.  Water-quality data for the Arkansas River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

Appendix 121
126 7-19-2002

8-26-2002

127 7-31-2002

8-26-2002

128 7-31-2002

8-26-2002

129 7-31-2002

8-26-2002

130 7-22-2002

8-27-2002

131 7-22-2002

8-27-2002

132 8-21-2002

133 8-21-2002

134 8-21-2002

135 8-20-2002

136 8-20-2002

137 8-20-2002

138 8-20-2002

139 8-19-2002

140 8-19-2002

141 7-24-2002

8-27-2002

142 7-23-2002

8-28-2002

143 7-23-2002

8-28-2002

144 7-23-2002

9-4-2002

145 7-23-2002

9-4-2002

146 8-28-2002

147 9-4-2002

148 9-4-2002

Site

number in

table 1

and fig. 7

Sampling

date

Conc Q% N Conc Q% N

0.10 ID 4 -- 19.2 ID 9

0.16 ID 4 -- 15.9 ID 9

0.45 ID 2 -- 24.4 ID 2

0.43 ID 2 -- 25.5 ID 2

0.57 66.7 35 -- 106 78.0 40

0.59 69.4 35 -- 119 90.2 40

-- -- -- -- -- -- --

-- -- -- -- -- -- --

0.58 ID 8 7.2 158 95.5 21

-- -- -- -- -- -- --

0.60 ID 4 6.0 186 ID 13

-- -- -- -- -- -- --

2.7 1

58.8–76.5 33 -- 22.2 98.2 54

1.5 78.6 27 -- 31.5 89.4 46

0.94 ID 13 -- 50 ID 10

1.2 1

25.0–50.0 27 -- 240 98.0 50

1.3 1

25.0–35.0 39 -- 300 96.9 64

1.4 1

10.5–18.4 37 -- 160 145.0–50.0 39

1.3 ID 13 -- 170 ID 12

1.4 ID 8 -- 270 ID 8

1.7 ID 17 -- 290 ID 17

0.80 ID 6 8.1 293 ID 14

-- -- -- -- -- -- --

1.0 ID 3 8.3 369 ID 11

-- -- -- -- -- -- --

1.6 ID 1 9.5 929 ID 1

-- -- -- -- -- -- --

1.2 ID 1 13 1,080 ID 6

-- -- -- -- -- -- --

1.2 ID 3 17.9 1,590 ID 11

-- -- -- -- -- -- --

0.70 ID 4 3.2 76.2 ID 4

0.20 ID 1 8.0 105 ID 1

1.1 ID 1 17.6 1,830 ID 2

Silica,

dissolved, in

mg/L as SiO2

Fluoride, dissolved, in mg/L Sulfate dissolved, in mg/L as SO4

Table 18.  Water-quality data for the Arkansas River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

122 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
126 7-19-2002

8-26-2002

127 7-31-2002

8-26-2002

128 7-31-2002

8-26-2002

129 7-31-2002

8-26-2002

130 7-22-2002

8-27-2002

131 7-22-2002

8-27-2002

132 8-21-2002

133 8-21-2002

134 8-21-2002

135 8-20-2002

136 8-20-2002

137 8-20-2002

138 8-20-2002

139 8-19-2002

140 8-19-2002

141 7-24-2002

8-27-2002

142 7-23-2002

8-28-2002

143 7-23-2002

8-28-2002

144 7-23-2002

9-4-2002

145 7-23-2002

9-4-2002

146 8-28-2002

147 9-4-2002

148 9-4-2002

Site

number in

table 1

and fig. 7

Sampling

date

Conc Q% N

-- <0.04 ID 2 --

-- <0.04 ID 2 --

-- <0.04 ID 2 --

-- <0.04 ID 2 --

-- <0.04 2

3.7–59.3 26 --

-- <0.04 2

3.7–59.3 26 --

-- 0.012 ID 7 0.22

-- 0.011 ID 7 --

395 0.05 ID 9 --

-- 0.04 ID 9 0.21

435 <0.04 ID 6 --

-- 1.65 ID 6 --

-- <0.015 2

3.8–61.5 25 --

-- 0.009 2

4.5–45.5 21 --

-- <0.015 ID 12 --

-- 0.008 ID 19 --

-- 0.009 28.6 41 --

-- 0.039 7.7 38 --

-- 0.20 ID 17 --

-- 0.20 ID 7 --

-- <0.015 ID 15 --

639 <0.04 ID 6 --

-- 0.07 ID 6 --

775 <0.04 ID 6 --

-- <0.04 ID 6 --

1,780 <0.04 ID 2 --

-- 0.12 ID 2 --

1,990 0.04 ID 6 --

-- 0.04 ID 6 --

2,970 0.05 ID 6 --

-- 0.04 ID 6 --

555 <0.015 ID 1 0.24

261 0.17 ID 1 0.55

3,210 0.06 ID 1 --

Solids,

dissolved,

residue on

evaporation at

180

o

C, in mg/L

Nitrogen, ammonia, dissolved, in mg/L as

N

Nitrogen,

organic plus

ammonia,

dissolved, in

mg/L as N

Table 18.  Water-quality data for the Arkansas River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

Appendix 123
126 7-19-2002

8-26-2002

127 7-31-2002

8-26-2002

128 7-31-2002

8-26-2002

129 7-31-2002

8-26-2002

130 7-22-2002

8-27-2002

131 7-22-2002

8-27-2002

132 8-21-2002

133 8-21-2002

134 8-21-2002

135 8-20-2002

136 8-20-2002

137 8-20-2002

138 8-20-2002

139 8-19-2002

140 8-19-2002

141 7-24-2002

8-27-2002

142 7-23-2002

8-28-2002

143 7-23-2002

8-28-2002

144 7-23-2002

9-4-2002

145 7-23-2002

9-4-2002

146 8-28-2002

147 9-4-2002

148 9-4-2002

Site

number in

table 1

and fig. 7

Sampling

date

Conc Q% N Conc Q% N

0.13 ID 2 <0.05 ID 2 <0.008

0.13 ID 2 <0.05 ID 2 <0.008

0.27 ID 2 <0.05 ID 2 <0.008

0.21 ID 2 <0.05 ID 2 <0.008

0.49 56.3 31 0.05 2

3.2–16.1 30 0.004

0.39 46.9 31 0.16 1

41.9–51.6 30 0.005

-- -- -- 0.11 ID 12 0.004

-- -- -- 0.30 ID 12 0.009

0.23 ID 8 0.40 ID 10 0.007

0.28 ID 8 0.24 ID 10 0.003

0.24 ID 2 0.49 ID 6 0.008

2.7 ID 2 1.06 ID 6 0.333

-- -- -- 0.51 1

29.6–33.3 26 --

-- -- -- <0.05 2

4.8–23.8 20 --

-- -- -- 0.80 ID 13 --

-- -- -- 3.2 42.9 20 --

-- -- -- 3.2 95.3 42 --

-- -- -- 5.41 97.6 40 --

-- -- -- 3.13 ID 18 --

-- -- -- 4.16 ID 8 --

-- -- -- 2.28 ID 15 --

0.71 ID 8 1.48 ID 6 0.024

0.79 ID 8 2.77 ID 6 0.095

0.44 ID 2 1.20 ID 6 0.009

0.38 ID 2 2.11 ID 6 0.036

2.0 ID 2 1.22 ID 2 0.014

1.2 ID 2 3.8 ID 2 0.041

0.85 ID 2 2.6 ID 7 0.007

0.81 ID 2 3.1 ID 7 0.027

0.39 ID 2 1.37 ID 6 0.017

0.39 ID 2 1.11 ID 6 0.019

0.31 ID 2 <0.013 ID 4 <0.002

0.95 ID 1 0.53 ID 1 0.054

0.43 ID 1 1.24 ID 2 0.022

Nitrogen, nitrite plus nitrate, in mg/L

as N Nitrogen,

nitrite,

dissolved, in

mg/L as N

Nitrogen, organic plus ammonia,

total recoverable, in mg/L as N

Table 18.  Water-quality data for the Arkansas River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

124 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
126 7-19-2002

8-26-2002

127 7-31-2002

8-26-2002

128 7-31-2002

8-26-2002

129 7-31-2002

8-26-2002

130 7-22-2002

8-27-2002

131 7-22-2002

8-27-2002

132 8-21-2002

133 8-21-2002

134 8-21-2002

135 8-20-2002

136 8-20-2002

137 8-20-2002

138 8-20-2002

139 8-19-2002

140 8-19-2002

141 7-24-2002

8-27-2002

142 7-23-2002

8-28-2002

143 7-23-2002

8-28-2002

144 7-23-2002

9-4-2002

145 7-23-2002

9-4-2002

146 8-28-2002

147 9-4-2002

148 9-4-2002

Site

number in

table 1

and fig. 7

Sampling

date

Conc Q% N Conc Q% N

-- 0.009 ID 2 <0.02 ID 2

-- 0.007 ID 2 <0.02 ID 2

-- 0.033 ID 2 <0.02 ID 2

-- 0.023 ID 2 <0.02 ID 2

-- 0.087 71.1 37 0.01 1

12.5–25.0 23

-- 0.142 84.2 37 0.07 95.8 23

0.025 0.085 ID 4 0.015 ID 8

0.131 0.200 ID 4 0.12 ID 8

-- 0.022 ID 16 <0.02 ID 10

0.011 0.022 ID 16 <0.007 ID 10

-- 0.020 ID 10 <0.02 ID 6

-- 0.23 ID 10 0.12 ID 6

-- <0.06 2

4.0–64.0 24 <0.02 24.0–76.0 24

-- 2.2 ID 4 1.7 ID 19

-- 0.210 ID 11 0.16 ID 11

-- 0.070 ID 11 0.04 ID 19

-- 0.060 1

12.1–18.2 32 0.03 117.1–37.1 34

-- 1.3 58.3 23 1.2 78.8 32

-- 0.76 ID 15 0.66 ID 15

-- 0.80 ID 4 0.73 ID 4

-- 0.47 ID 10 0.22 ID 11

-- 0.33 ID 8 0.10 ID 6

-- 0.31 ID 8 0.19 ID 6

-- 0.153 ID 8 0.03 ID 6

-- 0.037 ID 8 <0.02 ID 6

-- 0.199 ID 2 <0.02 ID 2

-- 0.076 ID 2 <0.02 ID 2

-- 0.119 ID 2 <0.02 ID 6

-- 0.103 ID 2 <0.02 ID 6

-- 0.034 ID 8 <0.02 ID 6

-- 0.029 ID 8 <0.02 ID 6

0.012 0.035 ID 2 0.006 ID 4

0.030 0.172 ID 1 0.017 ID 1

-- 0.024 ID 1 <0.02 ID 1

Phosphorus,

dissolved, in mg/L

Phosphorus, orthophosphate, dissolved,

in mg/L as P

Phosphorus, total recoverable, in

mg/L as P

Table 18.  Water-quality data for the Arkansas River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

Appendix 125
126 7-19-2002

8-26-2002

127 7-31-2002

8-26-2002

128 7-31-2002

8-26-2002

129 7-31-2002

8-26-2002

130 7-22-2002

8-27-2002

131 7-22-2002

8-27-2002

132 8-21-2002

133 8-21-2002

134 8-21-2002

135 8-20-2002

136 8-20-2002

137 8-20-2002

138 8-20-2002

139 8-19-2002

140 8-19-2002

141 7-24-2002

8-27-2002

142 7-23-2002

8-28-2002

143 7-23-2002

8-28-2002

144 7-23-2002

9-4-2002

145 7-23-2002

9-4-2002

146 8-28-2002

147 9-4-2002

148 9-4-2002

Site

number in

table 1

and fig. 7

Sampling

date

Conc Q% N

-- -- 4 <3 ID 2

-- -- 2 2 ID 2

-- -- 3 2 ID 2

-- -- 9 16 ID 2

2.6 4.4 290 230 1

51.9–55.6 26

2.5 3.3 54 100 1

25.9–29.6 26

2.9 -- -- -- -- --

2.7 -- -- -- -- --

2.3 -- 10 5 ID 12

2.5 -- 4 11 ID 12

-- -- 730 700 ID 8

-- -- 1,800 5,500 ID 8

-- -- 930 600 60.6 65

-- -- 300 260 91.3 45

-- -- 40 60 ID 12

-- -- 200 420 44.0 49

-- -- 440 440 1

28.1–31.3 63

-- -- 460 500 38.9 53

-- -- 3,900 4,200 ID 9

-- -- 430 660 ID 4

-- -- 520 940 ID 14

-- -- 270 380 ID 14

-- -- 160 270 ID 14

-- -- 240 210 ID 7

-- -- 86 280 ID 7

-- -- 2,500 3,300 ID 2

-- -- 540 940 ID 2

-- -- 200 120 ID 5

-- -- 68 150 ID 5

-- -- 140 120 ID 11

-- -- 140 290 ID 11

-- 3.8 75 77 ID 1

6.4 8.6 200 110 ID 1

-- -- 100 110 ID 4

Bacteria, fecal coliform, in colonies

per 100 mL Carbon,

organic,

dissolved,

in mg/L

Carbon, organic,

total

recoverable,

in mg/L

Bacteria,

E. coli ,

in colonies per

100 mL

Table 18.  Water-quality data for the Arkansas River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

126 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
126 7-19-2002

8-26-2002

127 7-31-2002

8-26-2002

128 7-31-2002

8-26-2002

129 7-31-2002

8-26-2002

130 7-22-2002

8-27-2002

131 7-22-2002

8-27-2002

132 8-21-2002

133 8-21-2002

134 8-21-2002

135 8-20-2002

136 8-20-2002

137 8-20-2002

138 8-20-2002

139 8-19-2002

140 8-19-2002

141 7-24-2002

8-27-2002

142 7-23-2002

8-28-2002

143 7-23-2002

8-28-2002

144 7-23-2002

9-4-2002

145 7-23-2002

9-4-2002

146 8-28-2002

147 9-4-2002

148 9-4-2002

Site

number in

table 1

and fig. 7

Sampling

date

Conc Q% N

20 40 <2 ID 2 <2

20 50 <2 ID 2 <2

<20 140 <2 ID 2 4

<20 70 <2 ID 2 <13

<20 440 2 1

89.7–93.1 28 1

<20 340 <2 2

3.4–58.6 28 <13

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- <0.6 ID 11 <0.8

-- -- 1.0 ID 5 2

-- -- 1.4 ID 13 1

-- -- 1.7 ID 5 2

-- -- 2.2 ID 17 2

-- -- 3.5 ID 9 3

-- -- 4.0 ID 13 4

-- -- 3.4 ID 8 4

-- -- 3.0 ID 9 4

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

-- -- -- -- -- --

Aluminum,

dissolved,

in μg/L

Aluminum, total

recoverable,

in μg/L

Arsenic, dissolved, in mg/L

Arsenic, total

recoverable,

in μg/L

Table 18.  Water-quality data for the Arkansas River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

Appendix 127
126 7-19-2002

8-26-2002

127 7-31-2002

8-26-2002

128 7-31-2002

8-26-2002

129 7-31-2002

8-26-2002

130 7-22-2002

8-27-2002

131 7-22-2002

8-27-2002

132 8-21-2002

133 8-21-2002

134 8-21-2002

135 8-20-2002

136 8-20-2002

137 8-20-2002

138 8-20-2002

139 8-19-2002

140 8-19-2002

141 7-24-2002

8-27-2002

142 7-23-2002

8-28-2002

143 7-23-2002

8-28-2002

144 7-23-2002

9-4-2002

145 7-23-2002

9-4-2002

146 8-28-2002

147 9-4-2002

148 9-4-2002

Site

number in

table 1

and fig. 7

Sampling

date

Conc Q% N

-- -- 0.1 ID 9

<10 -- 0.1 ID 9

20 -- <0.1 ID 2

10 -- <0.1 ID 2

50 -- <0.1 2

3.1–90.6 31

50 -- <0.1 2

3.1–90.6 31

-- -- -- -- --

-- -- -- -- --

-- -- -- -- --

-- -- -- -- --

-- -- -- -- --

-- -- -- -- --

80 70 -- -- --

270 260 0.03 2

3.3–93.3 29

80 80 <0.1 ID 12

90 80 <0.1 2

3.3–96.7 29

120 120 <0.1 2

2.6–92.3 38

230 220 -- -- --

250 240 -- -- --

240 240 -- -- --

250 250 -- -- --

-- -- -- -- --

-- -- -- -- --

-- -- -- -- --

-- -- -- -- --

-- -- -- -- --

-- -- -- -- --

-- -- -- -- --

-- -- -- -- --

-- -- -- -- --

-- -- -- -- --

-- -- -- -- --

-- -- -- -- --

-- -- -- -- --

Cadmium, dissolved, in mg/L

Boron,

dissolved,

in μg/L

Boron, total

recoverable,

in μg/L

Table 18.  Water-quality data for the Arkansas River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

128 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
126 7-19-2002

8-26-2002

127 7-31-2002

8-26-2002

128 7-31-2002

8-26-2002

129 7-31-2002

8-26-2002

130 7-22-2002

8-27-2002

131 7-22-2002

8-27-2002

132 8-21-2002

133 8-21-2002

134 8-21-2002

135 8-20-2002

136 8-20-2002

137 8-20-2002

138 8-20-2002

139 8-19-2002

140 8-19-2002

141 7-24-2002

8-27-2002

142 7-23-2002

8-28-2002

143 7-23-2002

8-28-2002

144 7-23-2002

9-4-2002

145 7-23-2002

9-4-2002

146 8-28-2002

147 9-4-2002

148 9-4-2002

Site

number in

table 1

and fig. 7

Sampling

date

Conc Q% N Conc Q% N Conc Q% N

0.1 ID 9 -- -- -- -- -- --

0.1 ID 9 -- -- -- -- -- --

0.1 ID 2 -- -- -- -- -- --

<0.1 ID 2 -- -- -- -- -- --

0.1 ID 19 -- -- -- -- -- --

0.1 ID 19 -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

<0.1 2

1.8–91.1 55 -- -- -- 1 160.0–74.3 34

<0.1 2

2.1–89.6 47 <0.8 22.1–95.7 46 <0.8 23.4–86.2 28

<0.1 ID 3 -- -- -- <1 ID 13

<0.1 2

2.0–93.9 48 -- -- -- 2 158.6–72.4 28

-- -- -- -- -- -- 2 1

48.7–56.4 38

<0.1 2

2.6–97.4 37 -- -- -- 1 122.2–36.1 35

<0.1 ID 1 -- -- -- 2 ID 19

-- -- -- -- -- -- 3 ID 5

-- -- -- -- -- -- 4 ID 13

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

Chromium, total recoverable,

in μg/L

Cadmium, total recoverable, in

μg/L Chromium, dissolved, in μg/L

Table 18.  Water-quality data for the Arkansas River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

Appendix 129
126 7-19-2002

8-26-2002

127 7-31-2002

8-26-2002

128 7-31-2002

8-26-2002

129 7-31-2002

8-26-2002

130 7-22-2002

8-27-2002

131 7-22-2002

8-27-2002

132 8-21-2002

133 8-21-2002

134 8-21-2002

135 8-20-2002

136 8-20-2002

137 8-20-2002

138 8-20-2002

139 8-19-2002

140 8-19-2002

141 7-24-2002

8-27-2002

142 7-23-2002

8-28-2002

143 7-23-2002

8-28-2002

144 7-23-2002

9-4-2002

145 7-23-2002

9-4-2002

146 8-28-2002

147 9-4-2002

148 9-4-2002

Site

number in

table 1

and fig. 7

Sampling

date

Conc Q% N Conc Q% N Conc Q% N

1.1 ID 8 1.8 ID 8 51 ID 9

-- -- -- -- -- -- 28 ID 9

0.8 ID 1 1.7 ID 1 15 ID 2

-- -- -- -- -- -- 13 ID 2

1.1 26.1 22 2.7 ID 17 11 1

4.9–7.3 40

-- -- -- -- -- -- 9 2.4 40

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- <10 ID 17

-- -- -- -- -- -- <10 ID 17

-- -- -- -- -- -- <10 ID 13

-- -- -- -- -- -- 25 ID 13

-- -- -- -- -- -- 10 1

18.6–20.3 58

1.4 46.4 27 2.4 62.8 42 44 23.9 45

-- -- -- -- -- -- 40 ID 13

-- -- -- -- -- -- <10 2

1.9–56.6 52

-- -- -- -- -- -- <10 2

1.5–45.5 65

-- -- -- -- -- -- 30 1

38.1–47.6 41

-- -- -- -- -- -- <10 ID 12

-- -- -- -- -- -- <10 ID 8

-- -- -- 10 ID 16 <10 2

4.8–71.4 20

-- -- -- -- -- -- <10 ID 11

-- -- -- -- -- -- <10 ID 11

-- -- -- -- -- -- <10 ID 11

-- -- -- -- -- -- <10 ID 11

-- -- -- -- -- -- <30 ID 2

-- -- -- -- -- -- <30 ID 2

-- -- -- -- -- -- <30 ID 5

-- -- -- -- -- -- <30 ID 5

-- -- -- -- -- -- <30 ID 11

-- -- -- -- -- -- <30 ID 11

-- -- -- -- -- -- <10 ID 4

-- -- -- -- -- -- <10 ID 1

-- -- -- -- -- -- <30 ID 1

Copper, dissolved, in μg/L Copper, total recoverable,

in μg/L Iron, dissolved, in μg/L

Table 18.  Water-quality data for the Arkansas River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

130 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
126 7-19-2002

8-26-2002

127 7-31-2002

8-26-2002

128 7-31-2002

8-26-2002

129 7-31-2002

8-26-2002

130 7-22-2002

8-27-2002

131 7-22-2002

8-27-2002

132 8-21-2002

133 8-21-2002

134 8-21-2002

135 8-20-2002

136 8-20-2002

137 8-20-2002

138 8-20-2002

139 8-19-2002

140 8-19-2002

141 7-24-2002

8-27-2002

142 7-23-2002

8-28-2002

143 7-23-2002

8-28-2002

144 7-23-2002

9-4-2002

145 7-23-2002

9-4-2002

146 8-28-2002

147 9-4-2002

148 9-4-2002

Site

number in

table 1

and fig. 7

Sampling

date

Conc Q% N Conc Q% N

120 ID 9 <1 ID 9 2

110 ID 9 <1 ID 9 1

190 ID 2 <1 ID 2 1

110 ID 2 <1 ID 2 --

650 36.4 21 <1 2

4.3–87 22 2

500 22.7 21 <1 2

4.3–87 22 1

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

90 1.5 64 <0.2 2

2.9–91.2 33 --

1,130 83.3 47 0.2 2

3.4–82.8 28 --

330 ID 13 <0.2 ID 8 --

640 1

8.8–10.5 56 <0.2 23.4–93.1 28 --

340 3.0 66 <0.2 2

2.5–97.5 39 --

150 2.3 42 -- -- -- --

1,000 ID 11 -- -- -- --

1,170 ID 5 -- -- -- --

3,840c ID 19 <0.2 ID 16 --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

Iron, total recoverable, in μg/L Lead, dissolved, in μg/L

Lead, total

recoverable,

in μg/L

Table 18.  Water-quality data for the Arkansas River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

Appendix 131
126 7-19-2002

8-26-2002

127 7-31-2002

8-26-2002

128 7-31-2002

8-26-2002

129 7-31-2002

8-26-2002

130 7-22-2002

8-27-2002

131 7-22-2002

8-27-2002

132 8-21-2002

133 8-21-2002

134 8-21-2002

135 8-20-2002

136 8-20-2002

137 8-20-2002

138 8-20-2002

139 8-19-2002

140 8-19-2002

141 7-24-2002

8-27-2002

142 7-23-2002

8-28-2002

143 7-23-2002

8-28-2002

144 7-23-2002

9-4-2002

145 7-23-2002

9-4-2002

146 8-28-2002

147 9-4-2002

148 9-4-2002

Site

number in

table 1

and fig. 7

Sampling

date

Conc Q% N Conc Q% N

9.5 ID 9 20.4 ID 9 --

10.7 ID 9 22.6 ID 9 --

7.7 ID 2 28.5 ID 2 --

7.7 ID 2 25.4 ID 2 --

18.9 47.5 39 77 1

40.9–45.5 21 --

29 80.0 39 77 1

40.9–45.5 21 --

33 ID 6 -- -- -- --

-- -- -- -- -- -- --

50 ID 16 -- -- -- --

162c ID 16 -- -- -- --

13.2 ID 14 -- -- -- --

141c ID 14 -- -- -- --

10 1

5.3–10.5 56 10.0 1.5 64 <0.01

52c 50.0 47 158 81.3 47 <0.01

40 ID 10 60 ID 13 <0.01

-- -- -- 20.0 1

7.0–12.3 56 <0.01

20 1

46.6–53.4 57 50 16.0–7.5 66 <0.01

40 19.0–31.0 41 40 1

2.7–5.4 36 <0.01

-- -- -- 60 ID 12 <0.01

-- -- -- 60 ID 5 <0.01

-- -- -- 170 ID 19 <0.01

7.4 ID 11 -- -- -- --

71c ID 11 -- -- -- --

12.8 ID 10 -- -- -- --

24 ID 10 -- -- -- --

36 ID 2 -- -- -- --

115c ID 2 -- -- -- --

8.1 ID 6 -- -- -- --

15.4 ID 6 -- -- -- --

43 ID 12 -- -- -- --

133c ID 12 -- -- -- --

8.2 ID 3 -- -- -- --

66 ID 1 -- -- -- --

643 ID 1 -- -- -- --

Manganese, dissolved, in μg/L Manganese, total recoverable,

in μg/L Mercury,

dissolved,

in μg/L

Table 18.  Water-quality data for the Arkansas River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

132 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
126 7-19-2002

8-26-2002

127 7-31-2002

8-26-2002

128 7-31-2002

8-26-2002

129 7-31-2002

8-26-2002

130 7-22-2002

8-27-2002

131 7-22-2002

8-27-2002

132 8-21-2002

133 8-21-2002

134 8-21-2002

135 8-20-2002

136 8-20-2002

137 8-20-2002

138 8-20-2002

139 8-19-2002

140 8-19-2002

141 7-24-2002

8-27-2002

142 7-23-2002

8-28-2002

143 7-23-2002

8-28-2002

144 7-23-2002

9-4-2002

145 7-23-2002

9-4-2002

146 8-28-2002

147 9-4-2002

148 9-4-2002

Site

number in

table 1

and fig. 7

Sampling

date

Conc Q% N Conc Q% N Conc Q% N

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

<0.01 ID 16 -- -- -- -- -- --

0.01 ID 4 2.7 79.3 28 3.9 89.3 27

0.01 ID 12 -- -- -- -- -- --

<0.01 ID 10 -- -- -- -- -- --

<0.01 2

4.8–90.5 20 -- -- -- -- -- --

<0.01 ID 12 -- -- -- -- -- --

0.01 ID 9 -- -- -- -- -- --

0.01 ID 3 -- -- -- -- -- --

0.01 ID 9 -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

-- -- -- -- -- -- -- -- --

Nickel, total recoverable,

in μg/L

Mercury, total recoverable,

in μg/L Nickel, dissolved, in μg/L

Table 18.  Water-quality data for the Arkansas River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

Appendix 133
126 7-19-2002

8-26-2002

127 7-31-2002

8-26-2002

128 7-31-2002

8-26-2002

129 7-31-2002

8-26-2002

130 7-22-2002

8-27-2002

131 7-22-2002

8-27-2002

132 8-21-2002

133 8-21-2002

134 8-21-2002

135 8-20-2002

136 8-20-2002

137 8-20-2002

138 8-20-2002

139 8-19-2002

140 8-19-2002

141 7-24-2002

8-27-2002

142 7-23-2002

8-28-2002

143 7-23-2002

8-28-2002

144 7-23-2002

9-4-2002

145 7-23-2002

9-4-2002

146 8-28-2002

147 9-4-2002

148 9-4-2002

Site

number in

table 1

and fig. 7

Sampling

date

Conc Q% N Conc Q% N

-- -- -- -- 0.1c ID 2

-- -- -- -- <0.1 ID 2

-- -- -- -- <0.1 ID 2

-- -- -- -- <0.1 ID 2

-- -- -- -- <0.2 2

3.4–93.1 28

-- -- -- -- <0.1 2

3.4–93.1 28

-- -- -- -- -- -- --

-- -- -- -- -- -- --

4 ID 13 5 -- -- --

4 ID 13 5 -- -- --

8 ID 13 9 -- -- --

28ac ID 13 32 -- -- --

2 ID 8 1 <0.04 ID 11

<2 ID 4 <2 <1 ID 5

2 ID 8 2 <0.04 ID 13

15c ID 5 13 <0.04 ID 5

14c 96.3 26 13 <0.04 ID 17

6 1

66.7–79.2 23 5 <0.04 ID 9

-- -- -- -- <0.04 ID 13

6 ID 8 6 <0.04 ID 8

7 ID 12 7 <0.04 ID 9

11 ID 10 10 -- -- --

15 ID 10 18 -- -- --

9 ID 12 10 -- -- --

13 ID 12 14 -- -- --

7 ID 2 7 -- -- --

9 ID 2 9 -- -- --

13 ID 7 13 -- -- --

9 ID 7 11 -- -- --

12 ID 12 11 -- -- --

10 ID 12 7 -- -- --

<2 ID 2 <2 -- -- --

1 ID 1 <2 -- -- --

5 ID 2 7 -- -- --

Selenium, dissolved, in μg/L Selenium, Silver, dissolved, in μg/L

total

recoverable,

in μg/L

Table 18.  Water-quality data for the Arkansas River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

134 Effect of Drought on Streamflow and Stream-Water Quality in Colorado, July through September 2002
Table 18.  Water-quality data for the Arkansas River Basin showing 2002 drought values, Colorado water-quality exceedances, and

percentiles relative to historical data for selected properties and constituents from July through September, 1978–2002.—Continued

[ft3/s, cubic feet per second; Conc, concentration; Q%, percentile (percentage of data less than or equal to reported value or concentration) of drought-sample 

constituent; N, total number of historical and drought samples; mg/L, milligrams per liter; μS/cm, microsiemens per centimeter at 25o Celsius; oC, degrees 

Celsius; E. coli, Escherichia coli; mL, milliliter; μg/L, micrograms per liter; CaCO3, calcium carbonate; SiO2, silica; SO4, sulfate; ID, insufficient number of 

samples (less than 20) to calculate percentile; <, less than; --, no drought-sample measurement; values or concentrations in bold type indicate 2002 Colorado 

water-quality exceedances; c, chronic water-quality exceedance; ac, acute and chronic water-quality exceedance]

1

 Possible percentile range because of uncensored ties in data.

2

 Possible percentile range because of censored or recensored ties in data.

126 7-19-2002

8-26-2002

127 7-31-2002

8-26-2002

128 7-31-2002

8-26-2002

129 7-31-2002

8-26-2002

130 7-22-2002

8-27-2002

131 7-22-2002

8-27-2002

132 8-21-2002

133 8-21-2002

134 8-21-2002

135 8-20-2002

136 8-20-2002

137 8-20-2002

138 8-20-2002

139 8-19-2002

140 8-19-2002

141 7-24-2002

8-27-2002

142 7-23-2002

8-28-2002

143 7-23-2002

8-28-2002

144 7-23-2002

9-4-2002

145 7-23-2002

9-4-2002

146 8-28-2002

147 9-4-2002

148 9-4-2002

Site

number in

table 1

and fig. 7

Sampling

date

Conc Q% N Conc Q% N

<0.3 <24 ID 9 40 ID 8

<0.3 <24 ID 9 20 ID 8

<0.3 <24 ID 2 -- -- --

<0.3 <24 ID 2 <20 ID 1

<0.3 <24 2

3.1–78.1 31 -- -- --

<0.3 <24 2

3.1–78.1 31 <20 24.8–14.3 20

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

<0.04 <6 2

2.9–55.9 33 <9 21.6–22.6 61

<0.3 12 71.4 27 20 2

70.2–83 46

<0.04 <6 ID 8 <9 ID 11

<0.04 <6 2

3.4–96.6 28 <9 21.8–21.4 55

<0.04 10 1

81.1–86.5 36 20 118.2–31.8 65

0.04 40 82.5 39 40 1

27.9–41.9 42

0.09 30 ID 10 40 ID 13

0.06 20 ID 6 30 ID 5

0.07 -- -- -- 30 ID 19

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

-- -- -- -- -- -- --

Silver, Zinc, total recoverable, in μg/L

total

recoverable,

in μg/L

Zinc, dissolved, in μg/L

Appendix 135
Chafin, D.T., and Druliner, A.D.—Effect of Drought on Streamflow and Stream-Water Quality in Colorado—Scientific Investigations Report 2006–5322