Water Quality of Storm Runoff and Comparison 

of Procedures for Estimating Storm-Runoff 

Loads, Volume, Event-Mean Concentrations, 

and the Mean Load for a Storm for Selected 

Properties and Constituents for Colorado Springs, 

Southeastern Colorado, 1992

by Paul von Guerard and William B. Weiss

U.S. GEOLOGICAL SURVEY

Water-Resources Investigations Report 94-4194

Prepared in cooperation with the

COLORADO SPRINGS CITY ENGINEERING DIVISION

Denver, Colorado 

1995
U.S. DEPARTMENT OF THE INTERIOR 

BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY 

Gordon P. Eaton, Director

The use of trade, product, industry, or firm names is for descriptive purposes only and does not imply 

endorsement by the U.S. Government.

For additional information write to: Copies of this report can be purchased from:

District Chief U.S. Geological Survey 

U.S. Geological Survey Earth Science Information Center 

Box 25046, MS 415 Open-File Reports Section 

Denver Federal Center Box 25286, MS 517 

Denver, CO 80225 Denver Federal Center

Denver, CO 80225
CONTENTS

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

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

Purpose and scope ...................................................................................................................................................... 2

Description of study area and sampling sites ............................................................................................................. 4

Acknowledgments....................................................................................................................................................... 5

Data-collection techniques, water-quality-sampling procedures, and quality-assurance procedures .................................. 5

Precipitation and flow data-collection techniques ..................................................................................................... 5

Water-quality-sampling procedures ........................................................................................................................... 6

Quality-assurance procedures .................................................................................................................................... 7

Water quality of storm runoff............................................................................................................................................... 7

Procedures for estimating single-storm-runoff loads, volume, and event-mean concentrations ......................................... 10

Single-storm local-regression models ........................................................................................................................ 14

Single-storm regional-regression models ................................................................................................................... 17

Comparison of observed and estimated single-storm-runoff loads, volume, and event-mean concentrations .......... 17

Procedures for adjustment of estimates from single-storm regional-regression models using local data ................. 20

Estimates of a mean load for a storm ........................................................................................................................i.......... 29

Comparison of procedures for estimating storm-runoff loads, volumes, event-mean concentrations, and

the mean load for a storm...................................................................................................................................................... 32

Summary .............................................................................................................................................................................. 33

References cited ................................................................................................................................................................... 35

Supplemental data ............................................................................................................................................................... 37

FIGURES

1. Map showing location of study area and storm-runoff-sampling sites................................................................. 3

2. Diagram showing flowchart for selection of model adjustment procedures......................................................... 24

3. Graph showing observed total-phosphorus, estimated total-phosphorus, and adjusted estimates

of total-phosphorus loads for storm-runoff load at site 2...................................................................................... 26

4. Graph showing observed total ammonia plus organic nitrogen as nitrogen, estimated total ammonia plus 

organic nitrogen as nitrogen, and adjusted estimates of total ammonia plus organic nitrogen as nitrogen 

for storm-runoff event-mean concentrations at site 2............................................................................................ 27

TABLES

1. Description of and selected land-use data for storm-runoff-sampling sites in Colorado Springs............................ 4

2. Summary statistics for selected constituents in storm runoff-sampling sites in Colorado Springs.......................... 8

3. Summary of detections of organic compounds in storm runoff-sampling sites in Colorado Springs...................... 11

4. Summary of single-storm local-regression models for storm-runoff loads and volume

for storm runoff-sampling sites in Colorado Springs................................................................................................ 15

5. Summary of single-storm local-regression models for storm-runoff event-mean concentrations-sampling sites

in Colorado Springs.................................................................................................................................................. 16

6. Ranges of values of each explanatory variable used in single-storm local- and regional-regression models.......... 18

7. Root-mean-square error from comparison of observed storm-runoff loads and volumes and estimated

storm-runoff loads and volumes from single-storm regional-regression models..................................................... 20

8. Summary of residual values for observed minus estimated values of storm-runoff loads, volume, and

event-mean concentrations...........................................................................................................................^........... 21

9. Effect of model-adjustment procedures on root-mean-square error and standard error of estimate for

storm-runoff loads and volume................................................................................................................................. 25

10. Effect of model-adjustment procedures on standard error of estimate for storm-runoff

event-mean concentrations........................................................................................................................................ 25

11. Summary of adjusted models for storm-runoff loads and volume............................................................................ 28

CONTENTS III
12. Summary of adjusted models for storm-runoff event-mean concentrations............................................................. 28

13. Ranges of values of explanatory variables used in development of regression models for mean load

for a storm................................................................................................................................................................. 29

14. Comparison of computed mean load for a storm based on daily mean water discharge and land-use

characteristics estimated mean load for a storm, and average of samples collected during rainfall runoff.............. 30

15. Summary of r2 values and standard error of estimate for regression models used to estimate mean load,

in pounds, of a storm based on daily mean water discharge and land-use characteristics........................................ 31

16. Precipitation and runoff characteristics for samples collected at storm-runoff sites in Colorado Springs............... 38

17. Values for instantaneous water discharge, pH, specific conductance, water temperature, fecal coliform, 

fecal streptococci, residual chlorine, cyanide, oil and grease, and phenols for storm-runoff sites 

in Colorado Springs.................................................................................................................................................. 39

18. Selected volatile-organic compounds for storm-runoff sites in Colorado Springs................................................... 41

19. Chemical oxygen demand, biochemical oxygen demand, specific conductance, alkalinity, dissolved solids,

suspended solids, major ions, nutrients and total-recoverable metals for storm-runoff sites Colorado Springs...... 52

20. Selected acid-base/neutral organic compounds for storm-runoff sites in Colorado Springs.................................... 57

21. Selected pesticide compounds for storm-runoff sampling sites in Colorado Springs.............................................. 64

CONVERSION FACTORS AND RELATED INFORMATION

Multiply By To obtain

cubic foot (ft3)

cubic foot per second (frVs)

foot (ft) 

gallon (gal)

inch (in.) 

mile (mi)

pound (Ib) 

quart (qt)

square mile (mi2)

0.028317

0.028317

0.3048 

3.785

25.4 

1.609

0.454 

0.9464

2.590

cubic meter

cubic meter per second

meter 

liter

millimeter 

kilometer

kilogram 

liter

square kilometer

Degree Fahrenheit (°F) can be converted to degree Celsius (°C) by using the following equation:

°C = 5/9 (°F-32).

Degree Celsius (°C) can be converted to degree Fahrenheit (°F) by using the following equation:

°F = 9/5 (°C + 32).

The following terms and abbreviations also are used in this report:

colonies per 100 milliliters (col/100 mL)

microsiemens per centimeter at 25 degrees Celsius (uS/cm)

milligram per liter (mg/L)

microgram per liter (ng/L)

IV CONTENTS
Water Quality of Storm Runoff and Comparison of 

Procedures for Estimating Storm-Runoff Loads, 

Volume, Event-Mean Concentrations, and the 

Mean Load for a Storm for Selected Properties 

and Constituents for Colorado Springs, 

Southeastern Colorado, 1992

ByPau\ von Guerard ancfWi\\\am B. Weiss

Abstract

The U.S. Environmental Protection Agency 

requires that municipalities that have a population 

of 100,000 or greater obtain National Pollutant 

Discharge Elimination System permits to characterize the quality of their storm runoff. In 1992, 

the U.S. Geological Survey, in cooperation with 

the Colorado Springs City Engineering Division, 

began a study to characterize the water quality of 

storm runoff and to evaluate procedures for the 

estimation of storm-runoff loads, volume and 

event-mean concentrations for selected properties 

and constituents.

Precipitation, streamflow, and water-quality 

data were collected during 1992 at five sites in 

Colorado Springs. Thirty-five samples were collected, seven at each of the five sites. At each site, 

three samples were collected for permitting purposes; two of the samples were collected during 

rainfall runoff, and one sample was collected during snowmelt runoff. Four additional samples 

were collected at each site to obtain a large enough 

sample size to estimate storm-runoff loads, volume, and event-mean concentrations for selected 

properties and constituents using linear-regression 

procedures developed using data from the Nationwide Urban Runoff Program (NURP). Stormwater samples were analyzed for as many as 

186 properties and constituents. The constituents 

measured include total-recoverable metals, volatile-organic compounds, acid-base/neutral organic 

compounds, and pesticides.

Storm runoff sampled had large concentrations of chemical oxygen demand and 5-day biochemical oxygen demand. Chemical oxygen

demand ranged from 100 to 830 milligrams per 

liter, and 5-day biochemical oxygen demand 

ranged from 14 to 260 milligrams per liter. Totalorganic carbon concentrations ranged from 18 to 

240 milligrams per liter. The total-recoverable 

metals lead and zinc had the largest concentrations 

of the total-recoverable metals analyzed. Concentrations of lead ranged from 23 to 350 micrograms 

per liter, and concentrations of zinc ranged from 

110 to 1,400 micrograms per liter.

The data for 30 storms representing rainfall 

runoff from 5 drainage basins were used to 

develop single-storm local-regression models. 

The response variables, storm-runoff loads, volume, and event-mean concentrations were modeled using explanatory variables for climatic,

physical, and land-use characteristics. The r2 for 

models that use ordinary least-squares regression 

ranged from 0.57 to 0.86 for storm-runoff loads 

and volume and from 0.25 to 0.63 for storm-runoff 

event-mean concentrations. Except for cadmium, 

standard errors of estimate ranged from 43 to 

115 percent for storm-runoff loads and volume and 

from 35 to 66 percent for storm-runoff event-mean 

concentrations. Eleven of the 30 concentrations 

collected during rainfall runoff for total-recoverable cadmium were censored (less than) concentrations. Ordinary least-squares regression should 

not be used with censored data; however, censored 

data can be included with uncensored data using 

tobit regression. Standard errors of estimate for 

storm-runoff load and event-mean concentration 

for total-recoverable cadmium, computed using 

tobit regression, are 247 and 171 percent.

Abstract
Estimates from single-storm regionalregression models, developed from the Nationwide Urban Runoff Program data base, were compared with observed storm-runoff loads, volume, 

and event-mean concentrations determined from 

samples collected in the study area. Single-storm 

regional-regression models tended to overestimate 

storm-runoff loads, volume, and event-mean concentrations. Therefore, single-storm local- and 

regional-regression models were combined using 

model-adjustment procedures to take advantage of 

the strengths of both models while minimizing the 

deficiencies of each model.

Procedures were used to develop singlestorm regression equations that were adjusted 

using local data and estimates from single-storm 

regional-regression equations. Single-storm 

regression models developed using model-adjustment procedures had standard errors of estimate 

smaller than the standard errors of estimate for the 

regional-regression equations. Reduction of standard error in percent ranged from -1,980 to -10.

Regression models that had been developed 

from the Nationwide Urban Runoff Program data 

base for estimating the mean load for a storm were 

evaluated. Mean load for a storm was estimated 

for selected constituents. Ninety-percent confidence intervals were computed for each mean load 

estimate. Estimated mean load for a storm was 

compared to mean load of a storm that was computed based on daily mean water discharge and 

land-use characteristics and was compared to the 

mean load from six samples collected during rainfall runoff. Generally, mean load for a storm, computed based on daily mean water discharge and 

land-use characteristics and on mean load from 

samples collected during rainfall runoff, was near 

or within the 90-percent confidence intervals for 

estimates of mean load for a storm.

INTRODUCTION

Urbanization usually increases the impervious 

area of a watershed, which increases storm-runoff rates 

and, subsequently, total volume of storm runoff. Associated with storm runoff are properties and constituents 

that can cause the degradation of water quality locally 

and in receiving waters downstream. Because of concerns about the effects of urban runoff on water quality, 

the Water Quality Act of 1987 contains provisions that 

specifically address storm-runoff discharges. The U.S. 

Environmental Protection Agency, under section 319

of the Water Quality Act of 1987, requires that States 

"assess the nature and extent of nonpoint sources of 

pollution." Section 402(p) of the same act requires that 

municipalities that have a population of 100,000 or 

greater obtain National Pollutant Discharge 

Elimination System (NPDES) permits to improve the 

quality of storm runoff.

Final rules published by the U.S. Environmental 

Protection Agency (1990) require that municipalities 

prepare permit applications to include, among other 

information, the following:

1. Characterization of the quantity and quality of 

storm runoff for three or more major storms 

at selected storm-water-discharge sites that 

represent different combinations of commercial, industrial, and residential land uses.

2. Estimates of annual-pollutant loads and eventmean concentrations for selected constituents 

for the cumulative discharges of storm-runoff 

discharge points in the study area.

In 1992, the U.S. Geological Survey, in cooperation with the Colorado Springs City Engineering Division, began a study to characterize the water quality 

of storm runoff in Colorado Springs and to compare 

techniques for the estimation of storm-runoff loads, 

volume, event-mean concentrations, and mean load 

for a storm for selected properties and constituents.

Purpose and Scope

This report presents water-quality data collected 

during 1992 to characterize the water quality of storm 

runoff in Colorado Springs. These data were collected 

to help meet the requirements of the NPDES permitting 

process. Precipitation, streamflow, and water-quality 

data were collected during 1992 at five sites in Colorado Springs (fig. 1, table 1). This report presents procedures for estimating storm-runoff loads, volume, and 

event-mean concentrations for selected properties and 

constituents at unmonitored sites in Colorado Springs 

and to make a comparison of several procedures for 

estimating storm-runoff loads, volume, and eventmean concentrations. In addition, the report presents 

estimates of a mean load for a storm.

Thirty-five samples were collected, seven at each 

of the five sites. At each site, three samples were collected for NPDES permitting purposes; two of these 

samples were collected during rainfall runoff, and one 

sample was collected during snowmelt runoff. Four 

additional samples were collected at each site to obtain 

a large enough sample size to estimate storm-runoff

Water Quality of Storm Runoff and Comparison of Procedures for Estimating Storm-Runoff Loads, Volume, EventMean Concentrations, and the Mean Load for a Storm for Selected Properties and Constituenta for Colorado Springs, 

Southeastern Colorado, 1992
104°50' 104D 40'

38°50'

Buchannan Street 

Beacon Street

Base from U.S. Geological Survey 

digital data, 1:100,000, 1977 

UTM projection 

Modified by KLH Engineering 

for City of Colorado Springs

4 5 MILES

I I

I I I I ] 

01234 5 KILOMETERS

EXPLANATION

1 STORMWATER RUNOFF 

» SAMPLING SITE

Figure 1. Location of study area and storm-runoff-sampling sites.

INTRODUCTION
Table 1. Description of and selected land-use data for storm-runoff-sampling sites in Colorado Springs

Site 

number Site name

. (fig-1)

1 Sixteenth Hole, Valley-Hi Golf Course

2 Chestnut Street at Douglas Creek

3 Beacon Street at Buchanan Street

4 Wahsatch Street at Cross Lane

5 Walmart at Eighth Street

Latitude 

and 

longitude

38°49'18"

104°45'42"

38°53'47"

104°50W

38°52'40"

104°49'36"

38051'18"

104048'58"

38°49'35"

iwsviy

Drainage-basin 

area 

(square miles)

0.125

.165

.173

.327

.049

Impervious 

area 

(percent)

58.1

37.5

55.9

34.2

40.1

Land use

Commercial

undeveloped

residential

Industrial

undeveloped

residential

commercial

Industrial

commercial

residential

Residential

commercial

public

undeveloped

Undeveloped

commercial

industrial

residential

Percentage 

of total 

drainage 

basin

61.1

23.0

15.9

54.7

35.9

8.5

0.9

79.5

17.8

2.7

79.4

9.3

8.3

3.0

43.0

39.9

10.3

6.8

loads, volume, and event-mean concentrations for 

selected properties and constituents using linearregression procedures developed using data from the 

Nationwide Urban Runoff Program (NURP). Stormwater samples were analyzed for as many as 186 properties and constituents (tables 16-21 in the "Supplemental Data" section at the back of this report). Some 

of the properties and constituents measured include pH, 

specific conductance, water temperature, chemical 

oxygen demand, biochemical oxygen demand, bacteria, dissolved and suspended solids, major ions, nutrients, residual chlorine, total-recoverable metals, oil and 

grease, phenols, volatile-organic compounds, acidbase/neutral organic compounds, and pesticides.

Computed, hereinafter called observed, values 

for storm-runoff loads, volume, and event-mean concentrations are compared by using root-mean-square 

error with the results from regional-regression models 

developed from data collected for the NURP (Ellis and 

others, 1984; Driver and Tasker, 1990). Procedures are 

presented for using local data to adjust estimates from 

single-storm regional-regression models.

Description of Study Area and Sampling Sites

The study area, the city of Colorado Springs, is 

located in and along the eastern slope of the southern

Rocky Mountains (fig. 1). The climate of the study 

area is semiarid. Annual precipitation for 1948-87 at 

the Colorado Springs airport ranged from 8.6 to 25.4 in. 

Mean annual precipitation at the airport was 15.2 in. 

Convective thunderstorms contribute most of the rainfall during May through September. Thunderstorms 

occur an average of 70 days each year (U.S. Geological 

Survey, 1970). Mean air temperatures are about 29°F 

in January and 70°F in July (Hansen and others, 1978).

Soils in the study area tend to be sandy, moderately deep to deep, and well drained to excessively well 

drained. The study area is underlain mainly by sandstone and shale and by alluvial and windlain deposits. 

The landform dominating the study area is the Colorado Piedmont. A more detailed description of the 

study area is discussed in von Guerard (1989). 

Another important aspect of the study area is the rate 

of growth associated with Colorado Springs. Population increased from 45,472 in 1950 to 281,140 in 

1990. Additionally, total area of Colorado Springs

increased from 9.4 mi2 in 1950 to 181.4 mi2 in 1990 

(Christine Lytle, Colorado Springs City Engineering 

Division, written commun., 1992).

Each of the sampling sites, except for site 4, is 

located near the outfall of a drainage basin. Drainagebasin areas range from 0.049 to 0.327 mi2, and a predominant land use can be attributed to each basin 

(table 1). However, all sites have a mixture of land

4 Water Quality of Storm Runoff and Comparison of Procedures for Estimating Storm-Runoff Loads, Volume, EventMean Concentrations, and the Mean Load for a Storm for Selected Properties and Constituents for Colorado Springs, 

Southeastern Colorado, 1992
uses, which is typical of Colorado Springs. For the purposes of this report, a drainage basin is defined by the 

local municipal storm-sewer network and is not necessarily delineated by the topography of the drainage 

basin. Selected descriptive data for the five drainage 

basins are listed in table 1. Except for site 4, all sites 

discharge into another part of the Colorado Springs 

storm-sewer system. Site 4 discharges directly into 

Monument Creek.

Site 1 is in southeastern Colorado Springs 

(fig. 1). The sampling site is in a 60-in. reinforced 

concrete pipe (RCP) and is accessed by a manhole. 

The manhole is located about 200 ft upstream from 

Spring Creek along the southern boundary fence of the 

Valley-Hi Golf Course and is south of the sixteenth 

hole. The sampling site is directly upstream from an 

18-in. side drain entering the RCP from the south.

Site 1 has a drainage-basin area of 0.125 mi2, of which 

58.1 percent is impervious area (table 1). Predominant 

land use in the drainage basin is commercial (table 1) 

and includes retail stores and two automobile dealerships that have repair facilities.

Site 2 is in northwest Colorado Springs (fig. 1). 

The sampling site is in a 72-in. RCP accessed by a manhole. The manhole is located about 100 ft southeast of 

the intersection of Garden of the Gods Road and Chestnut Street and is about 200 ft upstream from Douglas

Creek. Site 2 has a drainage-basin area of 0.165 mi , 

of which 37.5 percent is impervious area (table 1). 

Predominant land use is industrial and includes tool 

and machine forging, computer software, heating and 

air-conditioning manufacturing, and metallurgy 

companies.

Site 3 is located in north-central Colorado 

Springs (fig. 1). The sampling site is in a 48-in. RCP 

and is accessed by a manhole. The manhole is located 

on the northwest corner of Beacon Street at Buchanan 

Street and is about 400 ft east of Monument Creek.

Site 3 has a drainage-basin area of 0.173 mi2, of which 

55.9 percent is impervious area. Land use predominantly is industrial (table 1) and includes auto repair, 

machining, manufacturing, food-processing, welding, 

computer software, metal-fabrication, and paperdistribution companies.

Site 4 is in central Colorado Springs (fig. 1). The 

sampling site is in a 66-in. RCP accessed by a manhole. 

The manhole is about 0.7 mi upstream from Shocks 

Run and 75 ft from the southeast corner of Wahsatch 

Street and Cross Lane. Site 4 has a drainage-basin area

of 0.327 mi2, of which 34.2 percent is impervious area. 

Land use primarily is low-density residential (table 1) 

but includes some commercial businesses.

Site 5 is in southwest Colorado Springs (fig. 1). 

The sampling site is in a 42-in. RCP and is accessed by 

a manhole. The manhole is located about 30 ft 

upstream from a drainage channel leading to Bear 

Creek and is about 300 ft east of the southeast corner 

of a retail store. The sampling site is directly upstream 

from an 18-in. side drain entering the RCP from the 

northwest. Site 5 has a drainage-basin area of

0.049 mi2 of which 40.1 percent is impervious area 

(table 1). Land use in the drainage basin predominantly 

is undeveloped (43 percent); however, commercial 

land use composes 39.9 percent of the drainage-basin 

area (table 1). The undeveloped area is in the upper 

part of the drainage basin and did not contribute runoff 

during the events sampled; therefore, runoff sampled is 

considered to be representative of commercial land use. 

Commercial land use includes two automobile dealerships that have repair facilities, a gas station, and several retail stores.

Acknowledgments

The authors appreciate the support and cooperation provided by Christine Lytle, Leonard Miller, and 

Bruce Thorson of the city of Colorado Springs. The 

authors thank Daniel Bunting, El Paso County 

Regional Floodplain Administrator, for providing precipitation duration data. The authors also thank 

Seth Bacon, Evan Howe, and Dennis Young, student 

employees of the U.S. Geological Survey, for their 

untiring efforts in collecting and processing stormwater samples.

DATA-COLLECTION TECHNIQUES, 

WATER-QUALITY-SAMPLING 

PROCEDURES, AND QUALITYASSURANCE PROCEDURES

Collection of storm-runoff data in the urban 

environment and for the purposes of NPDES requires 

specialized techniques and procedures. The following 

is a description of the data-collection techniques and 

sampling procedures used for this study.

Precipitation and Flow Data-Collection 

Techniques

Two to four precipitation storage gages were 

installed in each drainage basin. These gages were 

inspected at least daily from May 25 to August 16, 

1992, and periodically, thereafter, until the completion

DATA-COLLECTION TECHNIQUES, WATER-QUALITY-SAMPLJNG PROCEDURES, AND QUALITY-ASSURANCE PROCEDURES
of the snowmelt sampling. Precipitation for each 

drainage basin was area weighted using Thiessen polygons (Chow, 1964). In addition to providing total precipitation for each storm sampled, data collected at 

precipitation storage gages were used to determine precipitation conditions for 6 to 72 hours prior to the collection of a sample. To meet NPDES requirements for 

sampled storms, precipitation could not exceed 0.10 in. 

during the 72 hours preceding the collection of samples. For the four additional samples collected for 

selected properties and constituents, precipitation 

could not exceed 0.05 in. during the 6 hours preceding 

sample collection.

The hydraulics of flow in storm-sewer systems is 

extremely complex, and when coupled with the safety 

and logistical problems associated with accessing 

storm sewers, the complex hydraulics make the accurate measurement of storm-water discharge difficult. 

Palmer-Bowles flumes were installed at each site to 

measure flow in the storm sewers (Kilpatrick and others, 1985). The Palmer-Bowles flume causes flow in 

the RCP to be subcritical at the flume approach and 

forces flow through critical depth in the flume throat. 

Kilpatrick and others (1985) developed calibration 

curves for the Palmer-Bowles flumes. These calibration curves are within ±10 percent of measured flow. 

Depth of flow in the RCP was measured using a gaspurge conoflow pressure-regulating system and a 

pressure transducer. Flow depth was recorded using 

dataloggers.

Water-Quality-Sampling Procedures

Thirty samples were collected during rainfall 

runoff, and five samples were collected during snowmelt runoff. Prior to sample collection, all samplecollection bottles were washed using a nonphosphate 

detergent and were rinsed using tap water, 1-percent 

hydrochloric acid solution, and pesticide-grade methanol. Initially, and after each storm was sampled, pumping-sampler-intake lines were cleaned, using the 

procedure just described; in addition, the lines were 

given a final rinse of organic-free water. Glass mason 

jars used for the collection of samples for bacteria analysis were sterilized using an autoclave.

Storm-runoff samples were obtained by manually collecting grab samples and by using automaticpumping samplers. Grab samples were collected for 

pH, bacteria, residual chlorine, total-recoverable cyanide, oil and grease, phenols, and volatile-organic 

compounds. Water temperature was measured from a 

grab sample immediately after collection. Grab 

samples were collected as depth-integrated point samples and were collected using Teflon USDH-81 samplers (Federal Inter-Agency Sedimentation Project, 

written commun., 1992) that were equipped with 1-qt 

glass jars. At all sites and at all flow depths, flow in the 

RCP was turbulent and well mixed.

Composite samples were collected for chemical 

oxygen demand, biochemical oxygen demand, specific 

conductance, alkalinity, dissolved and suspended solids, major ions, nutrients, total-recoverable metals, 

acid-base/neutral organic compounds, and pesticides. 

Composite samples were first collected discretely using 

automatic-pumping samplers equipped with Teflon 

intake lines and four 1-gal glass bottles. The samplers 

were activated by the datalogger when a predetermined 

flow in the RCP was exceeded. After the sampler was 

activated, samples were collected at intervals of 5 to 

30 minutes, depending on the flow in the RCP. Samples were collected until the water level in the RCP 

dropped below the sampler orifice. After the bottles 

were filled, they were capped with Teflon-lined lids, 

put on ice, and transported to a field laboratory for 

flow-weight compositing. Flow-weighted aliquots 

were split from the sample into a stainless-steel Teflonlined churn, using a Teflon cone-splitter that was 

equipped with Teflon tubing. The aliquot needed from 

each discrete sample used for flow weighting was 

determined using an arithmetic weighting formula:

Sv = (QSAMP*TVSR)/TQSC (1)

where

Sv = the aliquot from a particular discrete 

sample;

QS AMP = instantaneous flow when the particular 

discrete sample was collected;

TVSR = the total volume of flow-weighted 

sample needed for processing; and

TQSC = is the sum of instantaneous flows for 

all discrete samples from which aliquots will be drawn.

After compositing, samples were shipped to the 

U.S. Geological Survey National Water-Quality 

Laboratory in Arvada, Colorado, for analysis.

The concentration of the flow-weighted composite sample is used to represent the storm-runoff 

event-mean concentration. Storm-runoff load, in 

pounds, was computed by multiplying the event-mean 

concentration by the volume of storm runoff for the 

storm sampled and by a unit conversion constant.

Water Quality of Storm Runoff and Comparison of Procedures for Estimating Storm-Runoff Loads, Volume, EventMean Concentrations, and the Mean Load for a Storm for Selected Properties and Constituents for Colorado Springs, 

Southeastern Colorado, 1992
Quality-Assurance Procedures

Trip blanks and field-equipment blanks were collected and analyzed for all properties and constituents 

to evaluate potential field contamination. Trip blanks 

are sample bottles filled with water devoid of any 

organic or inorganic constituents. Field and laboratory 

spikes were used to evaluate recovery and potential 

loss of concentration of organic compounds. Field and 

laboratory spikes are sample water spiked with a constituent of a known concentration.

Trip blanks were collected to evaluate any possible contamination occurring during transport of the 

sample from the field to the analytical laboratory. Values and concentrations in trip blanks were almost equal 

to or less than the analytical detection limit for all properties and constituents. Values and concentrations in 

field-equipment blanks were almost equal to or less 

than the analytical detection limits for every property 

and constituent except for chemical oxygen demand 

and total-organic carbon indicating there was little or 

no field contamination.

Field and laboratory spikes for organic compounds were done to evaluate potential analytical 

recoveries and possible degradation of constituents 

from the time of collection to when samples were 

analyzed. Average percent recoveries for volatile 

organic compounds were 43 percent for field spikes 

and 67 percent for lab spikes. The percent recoveries 

of less than 100 percent for the spikes indicate some 

loss of constituent concentration between sample collection and analysis. Average percent recoveries for 

acid-base/neutral organic compounds were 80 percent 

for field spikes and 97 percent for laboratory spikes. 

For pesticide compounds, average percent recoveries 

were 80 percent for field spikes and 82 percent for laboratory spikes. Generally, recovery of constituents was 

less than 100 percent, especially for volatile organic 

compounds. However, percent recovery was greater 

than 100 percent for certain constituents. This large 

percent recovery can be accounted for by the possible 

matrix effects on certain spiked concentrations and by 

the precision of the analytical technique used in the 

analysis (Mary Olsen, U.S. Geological Survey, oral 

commun., 1993).

WATER QUALITY OF STORM RUNOFF

Storm-runoff water-quality data were collected 

at sites that represent commercial (sites 1 and 5), industrial (sites 2 and 3), and residential (site 4) land uses 

(table 1). The water-quality properties and constituents 

collected can be separated into the following major 

categories:

1. Properties pH, specific conductance, temperature, chemical oxygen demand, and biochemical oxygen demand,

2. Bacteria fecal coliform and fecal streptococci,

3. Dissolved and suspended solids and major ions,

4. Nutrients nitrogen and phosphorus,

5. Total-recoverable metals,

6. Total-organic carbon,

7. Organic compounds volatile, acid-base/neutral, 

and pesticides.

Three samples were collected at each site for 

NPDES permitting purposes. Four additional samples 

were collected for selected constituents that also 

were collected for NPDES purposes. The additional 

four samples were collected to provide a large enough 

sample size (seven samples per site) to estimate stormrunoff loads and event-mean concentrations for 

selected constituents using linear-regression procedures developed using data from the NURP. These data 

are summarized in table 2.

Median concentrations of chemical and 5-day 

biochemical oxygen demand were highest for site 4 

(table 2); the median concentration for chemical oxygen demand for site 4 was 330 mg/L and for 5-day 

biochemical oxygen demand was 86 mg/L. Storm runoff generally had a neutral pH. The median value of pH 

for commercial sites was 7.5, for industrial sites was 

7.3, and for the residential site was 7.4. Specific conductance of storm runoff was largest for samples collected during snowmelt runoff. Median specific 

conductance for all samples collected during snowmelt 

runoff was 385 |iS/cm; during rainfall runoff, the 

median specific conductance was 104 jlS/cm. Water 

temperatures ranged from 0.0 (during snowmelt runoff) to 24.5°C (table 17).

The maximum counts of fecal coliform and 

fecal streptococci were measured at sites 1 and 4 

(table 17). Median counts for all samples at sites 1 

and 4 were 4,900 and 17,000 col/100 mL. However, 

largest median counts for bacteria were in samples 

from site 4 at 4,900 col/100 mL for fecal coliform and 

20,500 col/100 mL for fecal streptococci.

Dissolved-solids concentrations ranged from 34 

to 4,240 mg/L (table 19) for all land uses, and the range 

of concentrations was similar for all sites. The largest 

concentrations of dissolved solids were measured from 

snowmelt samples. The largest concentration of suspended solids, 1,400 mg/L, was measured for site 5 

(table 19). The largest median concentration of suspended solids was 826 mg/L at site 5.

WATER QUALITY OF STORM RUNOFF
Water Quality c 

trations, endth

<D *

f

tn

o 0) 3*

Runoff andComparis Load fra Storm £

| S

|a

a?

 o g

 a a

li

a $

tt ni

3 i

|i

if° 1

||

(0 a "Op

if

Table 2. Summary statistics for selected constituents in storm runoff for storm-runoff-sampling sites in 

[mg/L, milligrams per liter, |ig/L, micrograms per liter; -, not available due to censored data]

Colorado Springs

Constituent

Summary 

statistic

Oxygen 

demand, 

chemical 

(high 

level) 

(mg/L)

Oxygen 

demand, 

biochemical, 

5-day 

(mg/L)

Solids, Solids, 

dls- sussolved pended 

(mg/L) (mg/L)

Nitro-

»IIA _ y "i 

iMitrogen, am>m^ 

"gerT **

gen 

(mg/L)

Nitrogen, 

nitrite, 

total, 

as 

nitrogen 

(mg/L)

Sixteenth Hole. Valley-Hi Golf C<

Number of

samples

Minimum

Maximum

Mean

Median

Number of

samples

Minimum

Maximum

Mean

Median

7

100

310

200

180

7

100

420

240

230

5

19

53

34

29

6

14

80

36

31

7 7

63 121

202 524

108 284

93 274

7 7

34 198

256 1280

94 595

63 464

7 7

0.28 0.9

0.98 2.4

0.60 1.8

0.67 1.7

Chestnut Street

7 7

0.23 .90

1.10 2.4

0.49 1.4

0.43 1.1

7

0.02

.11

.05

.04

Nitrogen, 

nitrate 

plus ' 

nitrite, 

total, 

as 

nltrogen

(mg/L)

Mirse f site 11

7

0.40

1.00

.73

.80

Phosihorus,

phorus

7

0.12

.45

.28

.29

phorus, C

dis- ml

solved, to

as rec

phos- era

phorus (ng

(mg/L)

7 7

0.08 <1

.28 

.13

.12 <1

at Douglas Creek (site 21

7

.03

.08

.04'

.04

7

.45

1.10

.80

.87

7

.09

.72

.24

.17

6 7

.06 <1

.21 

.11

.09 

Em Beacon Street at Buchanan Street (site 31

s i

5 3

oi

1?

II

Number of

samples

Minimum

Maximum

Mean

Median

7

120

300

210

200

7

26

74

51

51

7 7

54 101

168 340

100 220

87 220

7 7

0.48 1.6

1.50 4.0

1.01 2.9

.99 2.9

7

.03

.07

.05

.04

7

.66

1.40

.95

1.00

7

.16

.58

.36

.33

7 

.10 <

.51 

.23

.18 
Table 2. Summary statistics for selected constituents in storm runoff for storm-runoff-sampling sites in Colorado Springs-Conti

Constituent

Summary 

statistic

Oxygen 

demand, 

chemical 

(high 

level) 

(mg/L)

Oxygen 

demand, 

biochemical, 

5-day 

(mg/L)

Solids, 

dissolved 

(mg/L)

Solids, 

suspended 

(mg/L)

Nttroammonltrogen 

(mg/L)

Nitrogen,

plus 

organic,

nttro-

(mg/L)

Wnhsatrh Stn

Number of

samples

Minimum

Maximum

Mean

Median

7

190

500

310

330

5

29

140

84

86

6

74

908

229

100

7

116

848

472

512

7

0.16

1.00

0.49

0.39

7

1.6

5.3

3.8

3.8

Nitrogen, 

nitrite, 

total, 

as 

nitrogen 

(mg/L)

Nitrogen, 

nitrate 

plus 

nitrite, 

total, 

as 

nitrogen

(mg/L)

Phosphorus, 

total, 

as 

phosphorus 

(mg/L)

Phosphorus, 

dissolved, 

as 

phosphorus 

(mg/L)

Ca

mi

to

rec

era

set at Cross Lane (site 41

7

.03

.08

.05

.05

7

.36

.88

.59

.47

7

.22

1.20

.75

.72

5

.11

.38

.26

.27

7

<1

2

Walmart at FJyhth Street (site 51

Number of

samples

Minimum

Maximum

Mean

Median

7

160

830

340

260

7

29

260

94

67

6

67

4240

790

110

7

388

1400

846

826

7

.41

3.90

1.30

1.00

7

1.2

7.4

3.3

2.3

7

.03

.31

.09

.06

7

.69

1.80

1.20

1.20

7

.21

1.00

.60

.59

6

.09

.34

.19

.17

7

21

5

2

O
Samples were collected to characterize concentrations of nutrients (nitrogen and phosphorous) in 

storm runoff. Sites 3 and 5 had the largest median concentrations for ammonia as nitrogen and nitrate plus 

nitrite as nitrogen, 1.0 and 1.2 mg/L. Site 4 had the 

largest median concentrations for total ammonia plus 

organic nitrogen as nitrogen, and total and dissolved 

phosphorus at 3.8, 0.72, and 0.27 mg/L.

Generally, concentrations of total-recoverable 

metals were similar for all sites (table 19). Concentrations of total-recoverable lead were largest for sites 2 

and 5 and had a median concentration of 180 flg/L. 

Concentrations of total-recoverable copper, nickel, and 

zinc were largest for sites 2 and 5 and had median concentrations of 18.0,16.0, and 500 ^lg/L.

The largest median concentration of totalorganic carbon was 100 mg/L at site 4. The median 

concentration of total-organic carbon for sites 1, 2, 3, 

and 5 was 52 mg/L.

Each sample collected for volatile-organic compounds (V.OC) was analyzed for 61 constituents. The 

largest number of VOC's detected were 21 at site 4 and 

31 at site 5. The number of VOC's detected, the number of samples collected, and the number of times each 

VOC was detected are listed for each site in table 3. 

Generally, volatile organic compounds were detected 

more often in samples collected during snowmelt runoff than in samples collected during rainfall runoff. A 

possible explanation for the higher number of detections of volatile organic compounds in snowmeltrunoff samples is that these samples were collected at a 

lower temperature than were the samples collected 

during rainfall runoff. Volatile organic compounds 

volatilize at a slower rate at the lower temperatures 

during snowmelt runoff. The volatile organic compounds detected generally were associated with gasoline and other petroleum products.

Each sample collected for acid-base/neutral 

organic compounds was analyzed for 57 constituents. 

The largest number of acid-base/neutral organic compounds detected was 21 at sites 1 and 3 and 26 at site 2. 

The number of acid-base/neutral compounds detected, 

the number of samples collected, and the number of 

times each compound was detected is listed in table 3. 

Except for chlordane in the sample collected at site 4 on 

June 12, concentrations of pesticides were less than the 

analytical detection limits for all samples.

PROCEDURES FOR ESTIMATING 

SINGLE-STORM-RUNOFF LOADS, 

VOLUME, AND EVENT-MEAN 

CONCENTRATIONS

The NPDES permitting process requires the estimation of total annual pollutant loads and event-mean 

concentrations for 12 properties and constituents. The

12 properties and constituents are chemical oxygen 

demand (COD), 5-day biochemical oxygen demand 

(BOD), dissolved solids (DS), suspended solids (SS), 

total nitrogen (TN), total ammonia plus organic nitrogen as nitrogen (TKN), total phosphorus (TP), dissolved phosphorus (DP), total-recoverable cadmium 

(CD), total-recoverable copper (CU), total-recoverable 

lead (PB), and total-recoverable zinc (ZN). In a simplistic assessment, seasonal or annual storm-runoff 

loads, volume, and event-mean concentrations could be 

estimated using mean concentrations of properties and 

constituents from the set of sampled storms. However, 

better estimates of single-storm-runoff loads and eventmean concentrations can result by using multipleregression analysis to relate these response variables to 

climatic, physical, and land-use characteristics (Driver 

and Tasker, 1990). These regression models could be 

used with precipitation data and physical and land-use 

information to estimate single-storm-runoff loads, volume, and event-mean concentrations for individual 

storms at ungaged storm-runoff sites.

The form of the regression equation used for estimating single-storm-runoff loads, volume, and eventmean concentrations is a linear function of the logarithmic-transformed variables:

logY = j logXj+B 2 logX2 + ....

+ B N log XN 

Taking the antilogs, the equation becomes:

(2)

V 1 - Dn R Y -A., B1 Y A- B2 .....A. Y N BN 

, (3) f^

where

Y = estimated storm-runoff load,

volume, or event-mean concentration (response variable); 

BQ, BI, 62, BN = regression coefficients; 

XL X2,..., XN = climatic, physical, or land-use variables (explanatory variables); and 

N = number of climatic, physical, and 

land-use variables in the regression 

model.

A transformation bias is produced when logarithms of the estimated mean response (log of the 

response variable) is retransformed (equation 3). This 

transformation bias usually results in the underestimation of the estimated mean response. However, the 

major part of this transformation bias may be eliminated by multiplying the estimated mean response by a 

correction factor (Duan, 1983):

BCF = - Y 10e< 

n ^

(4)

10 Water Quality of Storm Runoff and Comparison of Procedures for Estimating Storm-Runoff Loads, Volume, EventMean Concentrations, and the Mean Load for a Storm for Selected Properties and Constituents for Colorado Springs, 

Southeastern Colorado, 1992
Table 3. Summary of detections of organic compounds in storm runoff for storm-runoff-sampling sites in Colorado Springs 

[All compounds in micrograms per liter]

Site Constituent

VOLATILE-ORGANIC COMPOUNDS

Sixteenth Hole, Valley-Hi Golf Course (site 1) Benzene, total

Ethyl-benzene, total

Naphthalene, total

Toluene, total

Xylene, water, whole, total recoverable

1,2,4-trimethyl benzene, water, whole, recoverable

1,3,5-trimethyl benzene, water, whole, recoverable

ACID-BASE/NEUTRAL ORGANIC COMPOUNDS

Benzogh-i-perylenel, 12-benzo perylene, total

Benzo-b-flouranthene, total

Bis (2-ethylhexyl) phthalate, total

Chrysene, total

Di-n-butyl phthalat, total

Fluoranthene, total

Indeno (1,2,3-cd) pyrene, total

Phenanthrene, total

Pyrene, total

VOLATILE-ORGANIC COMPOUNDS

Chestnut Street at Douglas Creek (site 2) Naphthalene, total

Toluene, total

Xylene, water, whole, total recoverable

1,2,4-trimethyl benzene, water, whole, recoverable

ACID-BASE/NEUTRAL ORGANIC COMPOUNDS

Anthracene, total

Benzo-a-anthracenel, 2-benzanthracene, total

Benzo-a-pyrene, total

Benzogh-i-perylenel, 12-benzo perylene, total

Benzo-b-fluoranthene, total

Benzo-k-fluoranthene, total

Bis (2-ethylhexyl) phthalate, total

Chrysene, total

Fluoranthene, total

Indeno (1,2,3-cd) pyrene, total

Phenanthrene, total

Pyrene, total

Number 

of 

samples

10

10

10

10

10

10

10

3

3

3

3

3

3

3

3

3

7

7

7

7

3

3

3

3

3

3

3

3

3

3

3

3

Number 

of 

detections

1

1

3

2

3

2

1

1

2

3

2

3

3

1

3

3

3

3

4

2

2

2

2

1

2

2

3

2

3

2

2

3

PROCEDURES FOR ESTIMATING SINGLE-STORM-RUNOFF LOADS, VOLUME, AND EVENT-MEAN CONCENTRATIONS 11
Table 3. Summary of detections of organic compounds in storm runoff for storm-runoff-sampling sites in Colorado Springs 

-Continued

Site Constituent

VOLATILE-ORGANIC COMPOUNDS

Beacon Street at Buchanan Street (site 3) Dichlorobromomethane, total

Naphthalene, total

Toluene, total

Xylene, water, whole, total recoverable

1,2,4-trimethyl benzene, water, whole, recoverable

1,3,5-trimethyl benzene, water, whole, recoverable

ACID-BASE/NEUTRAL COMPOUNDS

Anthracene, total

Benzoa-anthracenel, 2-benzanthracene, total

Benzo-a-pyrene, total

Benzogh-i-perylenel, 12-benzo perylene, total

Benzo-b-flouranthene, total

Benzok-fluoranthene, total

Bis (2-ethylhexyl) phthalate, total

Chrysene, total

Fluoranthene, total

Indeno (1,2,3-cd) pyrene, total

Phenanthrene, total

Pyrene, total

VOLATILE-ORGANIC COMPOUNDS

Wahsatch Street at Cross Lane (site 4) Benzene, total

Ethyl-benzene, total

Naphthalene, total

P-isopropyl toluene, water, whole, recoverable

Toluene, total

Xylene, water, whole, total recoverable

1,2,4-trimethyl benzene, water, whole, recoverable

1,3,5-trimethyl benzene, water, whole, recoverable

ACID-BASE/NEUTRAL ORGANIC COMPOUNDS

Benzo-a-pyrene, total

Benzo-b-fluoranthene, total

Benzok-fluoranthene, total

Bis (2-ethylhexyl) phthalate, total

Chrysene, total

Fluoranthene, total

Phenanthrene, total

Pyrene, total

Number 

of 

samples

8

8

8

8

8

8

3

3

3

3

3

3

3

3

3

3

3

3

8

8

8

8

8

8

8

8

3

3

3

3

3

3

3

3

Number 

of 

detections

1

6

1

2

1

1

1

1

2

1

2

2

3

2

2

1

2

2

1

1

4

1

6

4

3

1

1

1

1

3

1

2

2

2

12 Water Quality of Storm Runoff and Comparison of Procedures for Estimating Storm-Runoff Loads, Volume, EventMean Concentrations, and the Mean Load for a Storm for Selected Properties and Constituents for Colorado Springs, 

Southeestern Colorado, 1992
Table 3. Summary of detections of organic compounds in storm runoff for storm-runoff-sampling sites in Colorado Springs

Site Constituent

Number Number

of of

samples detections

Wahsatch Street at Cross Lane (site 4) 

 Continued

PESTICIDE COMPOUNDS

Chlordane, total

VOLATILE-ORGANIC COMPOUNDS

Walmart at Eighth Street (site 5) Benzene, total

Chloroform, total

Cis-l,2-dichloroethene, water, total

Ethyl benzene, total

N-butyl benzene, water, whole, recoverable

N-propyl benzene, water, whole, recoverable

Naphthalene, total

Toluene, total

Xylene, water, whole, total recoverable

1,1,1-trichloroethane, total

1,2,4-trimethyl benzene, water, whole, recoverable

1,3,5-trimethyl benzene, water, whole, recoverable

ACID-BASE/NEUTRAL ORGANIC COMPOUNDS

Anthracene, total

Bis (2-ethylhexyl) phthalate, total

Di-n-octyl phthalate, total

Di-n-butyl phthalate, total

Fluoranthene, total

N-butyl benzyl phthalate, total

Phenanthrene, total

Pyrene, total

9

9

9

9

9

9

9

9

9

9

9

9

3

3

3

3

3

3

3

3

1

5

1

1

1

1

6

5

4

2

3

1

1

3

1

2

3

2

2

3

PROCEDURES FOR ESTIMATING SINGLE-STORM-RUNOFF LOADS, VOLUME, AND EVENT-MEAN CONCENTRATIONS 13
where

BCF = the bias correction factor,

n = the number of observations in the data set,

and

e,- = least-squares residual for observation i from 

the calibration data set, in log units.

Single-Storm Local-Regression Models

Using data collected for 30 rainfall-runoff 

storms, single-storm local-regression models were 

developed for the Colorado Springs area for estimating 

storm-runoff loads for the 12 NPDES properties and 

constituents and for estimating storm-runoff volume 

and event-mean concentrations for the 12 NPDES 

properties and constituents. The data for 30 storms 

from 5 drainage basins (6 storms in each drainage 

basin) are listed in tables 16 and 19. Data collected 

for snowmelt samples (the November and December 

samples) were not available at the time of this analysis 

and, thus, were not included in the development of the 

local-regression models. Also, techniques for estimating storm-runoff loads, volumes, and event-mean 

concentrations were developed using data for rainfallrunoff conditions (Ellis and others, 1984; Driver and 

Tasker, 1990), and the snowmelt samples represent different hydrologic processes and need to be considered 

separately. The models were developed using ordinary 

least-squares regression, except for total-recoverable 

cadmium (CD). The CD data set had 11 of the 30 analyses reported as less than (censored) values. Ordinary 

least-squares regression should not be used with censored data. However, censored data can be included 

with uncensored data using tobit regression, which is 

similar to least-squares regression, in which the 

parameter estimates are fit using maximum-likelihood 

estimation (Helsel and Hirsch, 1992). Except for two, 

all CD concentrations were 3 |ig/L or less (table 19); 

however, the CD concentration of 21 |lg/L was not 

included in this analysis because it is not considered 

representative of storm runoff in the study area. Stormrunoff loads, volume, and event-mean concentrations 

(response variables) were modeled using the following 

climatic, physical, and land-use characteristics 

(explanatory variables):

1. Total rainfall (TRN), in inches,

2. Total contributing drainage-basin area (DA), in

3. Impervious area (IA), as a percent of total contributing drainage-basin area,

4. Industrial land use (LUI), as a percent of total 

contributing drainage-basin area,

5. Commercial land use (LUC), as a percent of total 

contributing drainage-basin area,

6. Residential land use (LUR), as a percent of total 

contributing drainage-basin area,

7. Nonurban land use (LUN), as a percent of total 

contributing drainage-basin area,

8. Period (in days) preceding collection of a sample 

having less than 0.10 in. of precipitation (DD).

The RSQUARE procedure (Statistical Analysis 

System Institute, Inc., 1990) was used to determine 

which combination of explanatory variables composed 

the most suitable regression model. The RSQUARE 

procedure performs all possible linear regressions for 

all possible combinations of explanatory variables and 

determines the subsets of explanatory variables that

have the largest r2 value (Statistical Analysis System 

Institute, Inc., 1990). For the models to have a hydrologic and physiographic basis, only subset regression 

models including the explanatory variables TRN and 

DA were evaluated. The most suitable regression 

model was selected on the basis of the statistical significance of explanatory variables in the regression, the

values of r2, and checked using other model selection 

criteria (Statistical Analysis System Institute, Inc.,

1990). An r2 value is the proportion of the total variation of the response variable that is explained by the 

explanatory variables. For certain properties and 

constituents, all of the possible regressions included 

explanatory variables that were not significant at the 

5-percent confidence level. Therefore, some regression 

models that were selected as the most suitable included 

explanatory variables that were not significant at the 

5-percent confidence level (tables 4 and 5). However, 

inclusion of these variables in the models improved the

computed r2 and were considered useful predictors of 

the dependent variables. For event-mean concentrations for BOD, the local-regression model was not significant at the 5-percent confidence level (table 5). For 

evaluating all possible regression models (RSQUARE 

procedure) for storm-runoff loads and for event-mean 

concentrations for CD, only uncensored data were used 

(19 of the 30 values for CD were uncensored).

Plots of residual (observed values minus estimated values) compared to estimated values were 

analyzed to evaluate the constant variance (homoscedasticity) of the residuals. Residual plots for all of the 

most suitable models indicate that the variance of the 

residuals generally is constant throughout the entire

14 Water Quality of Storm Runoff and Comparison of Procedures for Estimating Storm-Runoff Loads, Volume, EventMean Concentrations, and the Mean Load for a Storm for Selected Properties and Constituents for Colorado Springs, 

Southeastern Colorado, 1992
PROCEDURES FOESTIMATING SINGLE-STORM-RUNOFF LOADS, VOLUME, AND EVENT-MEAN CONCE

[Bo, the regression coefficient that is the intercept in the regression model; Bj and Bn, regression coefficients; TRN, total rainfall; DA, total contributing drain

LUI, industrial land use; LUC, commercial land use; LUR, residential land use; LUN, nonurban land use; DD, period preceding collection of a sample having 

correction factor; r2, the coefficient of determination; COD, chemical oxygen demand, in pounds; BOD, 5-day biochemical oxygen demand, in pounds; DS, di

solids, in pounds; TN, total nitrogen, in pounds; TKN, total ammonia plus organic nitrogen as nitrogen, in pounds; TP, total phosphorus, in pounds; DP, dissolv

recoverable cadmium, in pounds; CU, total-recoverable copper, in pounds; PB, total-recoverable lead, in pounds; ZN, total-recoverable zinc, in pounds; RUN, 

(*) indicates the explanatory variable is not significant at the 5 percent level; dashes indicate that the variable is not included in the model; In, natural log; NA, n

is:

Y = B0 X1 B1 ...XnBn(BCF)

Response 

variable BO

COD 

BOD 

DS 

SS 

TN 

TKN 

TP 

DP 

CD1 

CU 

PB 

ZN 

RUN

17,167 

1,000 

188,799 

1,812 

0.48 

.0001 

5.98 

1.89* 

-5.09 

.00003 

750 

359 

32.5

'equation form is y = 6

TRN 

(Inches)

0.92 

.64 

.70 

1.36 

.89 

.69 

1.00 

.86 

1.46 

1.06 

1.36 

1.01 

.98

Bo + e InTl

Explanatory variables

DA 

,"" IA + 1 LUI + 1 LUC + 1

miles) (P8"*"*) (Percent) (percent)

2.51 -- ~ 0.63 

0.66 - -0.30 

1.51 - -.66 

.17* 

.05* 2.15 

9.34 - 2.77 4.64 

.24* - -.33 

.39* - -.19 

-.087 .10 

7.56 - 2.32 3.59 

-.78 - -.95 -1.15 

3.20 ~ ~ .58 

7.86 - 2.24 3.80

¥} ¥} ¥}

RN l , JnDA 2 , Jn(IA+l) 3BCF.

T C "T~ C

LUR + 1 LUN + 1 DD 

(percent) (percent) (days)

-0.81 0.86 -- 

 

-1.30 .38 - 

.38 - 

.55 - - 

3.51 - 

----- 

~ 

2.99 - 

-1.16* - - 

-1.70 1.30 - 

2.92 - 

(O
O)

Hi

Table 5. Summary of single-storm local-regression models for storm-runoff event-mean concentrations for storm-runoff-samplin

§»

fa

(O Q.

If

[Bo, the regression coefficient that is the intercept in the regression model; B[ and Bn, regression coefficients; TRN, total rainfall; DA, total contributing draina

LUI, industrial land use; LUC, commercial land use; LUR, residential land use; LUN, nonurban land use; DD, period preceding collection of a sample having 

correction factor; r2, the coefficient of determination; COD, chemical oxygen demand, in milligrams per liter (mg/L); BOD, 5-day biochemical oxygen demand

SS, suspended solids, in mg/L; TN, total nitrogen, in mg/L; TKN, total ammonia plus organic nitrogen as nitrogen, in mg/L; TP, total phosphorus, m mg/L; DP

recoverable cadmium, in micrograms per liter Qig/L); CU, total-recoverable copper, in tlg/L; PB, total-recoverable lead, in tlg/L; ZN, total-recoverable zinc, in 

Runoff am Load fra

II

iparlson ol

1 for Selecl

a*

if

IfS w

8 gO 21

11

II

§ 52

s o"5

oj

II

vaiiauic 13 uui si

Response 

variable

COD

BOD1

DS

SS

TN

TKN

TP

DP

CD2

CU

PB

ZN

LglUUCUlll al UK- J pel

Bo

6,558

115,432

35.5

242,384

.88*

.06

.0055

.0046

-.097*

15

39,346

347

cent ICVGI, uaoi

TRN 

(Inches)

-0.02*

-.35*

-.37

.36*

-.16*

-.28

.02*

-.22*

.26*

.02

.57

.12*

.KfO 1UU11-AIC Ulal i

DA 

(square 

miles)

-2273

-6.64

.04*

-0.57

-.36

-.12*

-1.98

-1.41

-.22

-.43

-.73

-.65

LUG voiiauic la "'

IA + 1 

(percent)

-

-

-

-1.80

-

.49*

-

-

_

-

-1.65

-

Hi iii^iuucu ill UK lliuuci, ill, iiau

Y = B0 X1BI...XnBn(BCF)

Explanatory variables

LUI + 1 LUC + 1 

(percent) (percent)

-.92 -1.46

-2.24 -3.52

-

_

_

_

-.34

-.25

-.148

-.30

_

-.43

141(11 lUg, l^rt, 11U>\ appiicouic, UK 1U1111 UI IC

LUR+1 

(percent)

-

-

--

-

0.35

-

-1.27

.93

_

-

~

LUN + 1 

(percent)

-1.02

-2.59

0.19

~

-.24

-

-.72

-.60

_

-

-

DD 

(days)

.28 

.17

m

I

'regression model significant at the 20 percent level.

^equation form is

y = eBo +elnTRN + eInDA + eInLUC+l

BCF.

I?

II
range of prediction. Because hydrologic data usually 

are skewed when using parametric statistical techniques, such as RSQUARE, data need to be transformed to minimize the heteroscedasticy of residuals 

and to linearize the x,y relation. Response and explanatory variables used in the RSQUARE procedure were 

log transformed (base 10).

The local-regression models for storm-runoff 

loads, volume, and event-mean concentrations and the

corresponding BCF, r2 values, and the standard error of 

estimate are listed in tables 4 and 5. The standard error 

of estimate is an estimate of the standard deviation 

about the regression. The smaller the standard error of 

estimate, the more precise will be the predictions 

(Driver and Tasker, 1990). The standard error of estimate, in percent, was calculated for all the local-regression models using the following equation (Driver and 

Tasker, 1990):

SE = 100 { [e (msex 5.302) -1]}

0.5

(5)

where

2. The process involving the effect of the explanatory variables on the water-quality constituent 

is not well understood.

3. The explanatory variable is a surrogate for another 

variable.

4. The apparent significance of an explanatory variable may be due to chance and, therefore, the 

relation may be spurious.

Use of the local-regression models listed in 

tables 4 and 5 need to be limited to the ranges of climatic, physical, and land-use (explanatory) variables 

listed in table 6. If values outside these ranges are used 

in the local- regression models, the standard errors 

may be considerably larger than the values reported in 

tables 4 and 5. As the local-regression models are 

applied to drainage-basin areas and to storms larger 

than the average drainage-basin area or storm volume 

of the observation sites, the accuracy of estimates of 

storm-runoff loads, volume, and event-mean concentrations decreases.

SE = the standard error of estimate, in percent; 

mse = the mean square error, in log (base 10)

units; and

5.302 = the square of the conversion of log base10 values to natural logs.

The values of r2 that use ordinary least-squares 

regression ranged from 0.57 to 0.86 for storm-runoff 

loads and volume (table 4) and from 0.25 to 0.63 for 

storm-runoff event-mean concentrations (table 5). 

Except for CD, standard errors of estimate range from 

43 to 115 percent for storm-runoff loads and volume 

and 32 to 66 percent for storm-runoff event-mean concentrations (tables 4 and 5). Standard errors of estimate 

for storm-runoff load and event-mean concentration for 

CD were 247 (table 4) and 171 percent (table 5). The 

accuracy of the load, volume, and concentration models cannot be compared on the basis of standard error of 

estimate because the units of the response variable for 

each model are different (Hoos and Sisolak, 1993).

The explanatory variables generally had signs 

(positive or negative) that were hydrologically logical. 

However, occasionally, the signs on individual explanatory variables seem to be counter intuitive. Driver and 

Tasker (1990) list the following explanations for why 

the signs of some regression coefficients (explanatory 

variables) may be counter intuitive:

1. Significant cross-correlation between explanatory 

variables causes multicollinearity problems in 

the local-regression models, however, this is 

accounted for in the RSQUARE procedure.

Single-Storm Regional-Regression Models

Procedures for estimating single-storm runoff 

loads, volume, and event-mean concentrations were 

developed by Ellis and others (1984) and Driver and 

Tasker (1990) for 11 of the 12 properties and constituents required for the permitting process. Regionalregression equations for BOD were not developed. 

Linear-regression equations were developed from data 

collected by the NURP. Equations developed by Ellis 

and others (1984) were developed using NURP data 

collected in the Denver metropolitan area. The Driver 

and Tasker (1990) equations were developed from the 

NURP data base and include sets of equations for three 

geographically distinct regions delineated by mean 

annual rainfall. The Colorado Springs area is included 

in Region 1. Comparison of estimates from these 

regional-regression models with observed storm-runoff 

loads, volume, and event-mean concentrations for 

samples collected in the study area will be useful in 

selecting the most appropriate method for estimating 

single-storm runoff loads, volume, and event-mean 

concentrations.

Comparison of Observed and Estimated 

Single-Storm-Runoff Loads, Volume, and 

Event-Mean Concentrations

Storm-runoff loads, volume, and event-mean 

concentrations estimated from single-storm regionalPROCEDURES FOR ESTIMATING SINGLE-STORM-RUNOFF LOADS, VOLUME, AND EVENT-MEAN CONCENTRATIONS 17
Table 6. Ranges of values of each explanatory values of each explanatory variable used in single-storm 

local- and regional-regression models

[TRN, total rainfall, in inches; DA, total contributing drainage area, in square miles; IA, impervious area, in percent; DRN, 

duration of rainfall, in minutes; COD, chemical oxygen demand; DS, dissolved solids; SS, suspended solids; TN, total nitrogen; 

TKN, total ammonia plus organic nitrogen as nitrogen; TP, total phosphorus; DP, dissolved phosphorus; CD, total-recoverable 

cadmium; CU, total-recoverable copper; PB, total-recoverable lead; ZN, total-recoverable zinc; RUN, volume of runoff in 

cubic feet; dashes, no data available]

Response 

variable

Explanatory 

variable Minimum Maximum Mean Median

Local-regression model for storm-runoff-sampling sites in Colorado Springs

(!)

(!)

(!)

SS

TRN

DA

IA

DRN

0.05

.049

34.2

7.00

0.41

.327

58.1

39.3

0.17

.17

45.2

62.1

0.14

.16

40.1

35.0

Driver and Tasker (1990) regression model

COD

COD

COD

DS

DS

DS

SS

SS

SS

SS

TN

TN

TN

TKN

TKN

TKN

TP

TP

DP

DP

DP

CD

CD

CD

CU

CU

CU

PB

PB

PB

ZN

ZN

ZN

TRN

DA

IA

TRN

DA

IA

TRN

DA

IA

DRN

TRN

DA

IA

TRN

DA

IA

TRN

IA

TRN

DA

IA

TRN

DA

IA

TRN

DA

IA

TRN

DA

IA

TRN

DA

IA

.02

.05

-

.02

.01

11

.03

.05

10

.03

.01

-

.03

.05

0.03

.03

.01

-

.03

0.01

.02

.01

.02

.004

.02

.01

..

1.99

17.50

-

1.23

80.5

98.9

1.99

17.50

2,220

1.99

80.5

-

1.99

80.5

-

1.99

1.99

4.00

-

.93

3.03

-

1.99

4.00

-

1.99

4.00

-

1.99

4.00

.36

1.18

.36

4.92

60.6

.39

1.45

358

.41

6.37

-

.37

4.79

-

0.38

.39

.50

-

.26

0.36

-

.37

.55

~

.39

.47

-

.39

.53

_

.26

.12

-

.28

.12

57

.29

.12

231

.29

.11

.28

.12

0.28

.28

.11

-

.22

0.12

.27

.12

.28

.11

.28

.12

18 Wster Quality of Storm Runoff and Comparison of Procedures for Estimating Storm-Runoff Loads, Volume, EventMean Concentrations, and the Mean Load for a Storm for Selected Propertlea and Constituenta for Colorado Springs, 

Southeastern Colorado, 1992
Table 6. Ranges of values of each explanatory values of each explanatory variable used in single-storm 

local- and regional-regression models-Continued

Response 

variable

RUN 

RUN 

RUN

Explanatory 

variable

TRN 

DA 

IA

Minimum

.02 

.004 

0

Maximum

1.99 

80.5 

98.9

Mean

.36 

2.93 

56.7

Median

.26 

.11 

57

Small basins [Ellis and others (1984)] regression model 

TRN .03 1.99 .35 

DA .09 .63 .20 

IA .60 91 36.7 

Small and large basins [Ellis and others (1984)] regression model 

TRN ~

DA 0.09 24.7 6.1 

IA .6 91 31.8

.12

38

0.20

24

where

'includes storm-runoff load and event-mean concentration for chemical oxygen demand, dissolved solids, suspended solids, 

total nitrogen, total ammonia plus organic nitrogen as nitrogen, total phosphorus, dissolved phosphorus, total-recoverable cadmium, 

total-recoverable copper, total-recoverable lead, total-recoverable zinc, and volume of runoff for RUN.

Includes storm-runoff load for chemical oxygen demand, suspended solids, total nitrogen, total phosphorus, total-recoverable 

lead, total-recoverable zinc, and volume of runoff for RUN.

regression models were compared to observed values \_ 

from data collected at five sites in the study area in 1992 r. n -|2 

(fig. 1, table 1). The response variables estimated by RMSE = 

Driver and Tasker (1990) are storm-runoff loads for 

COD, SS, DS, TN, TKN, TP, DP, CD, CU, PB, and ZN; 

storm-runoff volume, and event-mean concentrations for 

COD, SS, DS, TN, TKN, TP, DP, CD, CU, PB, and ZN. 

The response variables estimated by Ellis and others 

(1984) are storm-runoff loads for COD, SS, TN, TP, PB, 

and ZN and storm-runoff volume. Driver and Tasker 

(1990) developed two sets of single-storm regionalregression models for storm-runoff loads and volume. 

The first set of models was based on a stepwise regression analysis of 13 explanatory variables including TRN, 

DA, IA, land-use, and regional climatic variables. The 

second set of models was based on three explanatory 

variables TRN, DA, and IA. The single-storm 

regional-regression models for storm-runoff event-mean 

concentrations are based on stepwise regression analysis 

of the same 13 explanatory variables used to develop 

models for storm-runoff load and volume. Single-storm 

regional-regression models developed by Ellis and 

others (1984) for storm-runoff loads and volume were 

based on three explanatory variables TRN, DA, and 

IA.

(6)

Comparisons of observed and estimated stormrunoff loads, volume, and event-mean concentrations 

were made using the root-mean-square error (RMSE) of 

estimate from the equation:

RMSE = the root-mean-square error in log units

(base 10);

Oj = ith observed value; 

EJ = ith estimated value from the regionalregression model; and

n = the number of observations in the data set. 

Generally, when compared to observed values, 

the 3-variable models that were developed by Driver 

and Tasker (1990) for estimating storm-runoff loads 

had the smallest RMSE (table 7). For estimates of 

storm-runoff volume, when compared to observed values, the multivariate model developed by Driver and 

Tasker (1990) had the smaller RMSE (table 7).

An evaluation of residuals from a comparison of 

observed and estimated storm-runoff loads, volume, 

and event-mean concentrations can be used to determine the direction of bias of estimated values compared to observed values. Compared to observed 

values, most regional-regression models tended to 

overestimate (negative sign in table 8) storm-runoff 

loads, volume, and event-mean concentrations. However, the direction of bias was not consistent for all 

properties and constituents and runoff volume 

(table 8).

PROCEDURES FOR ESTIMATING SINGLE-STORM-RUNOFF LOADS, VOLUME, AND EVENT-MEAN CONCENTRATIONS 1 9
Table 7. Root-mean-square error from comparison of observed storm-runoff loads and volumes and estimated storm-runoff 

loads and volumes from single-storm regional-regression models

[COD, chemical oxygen demand, in pounds; DS, dissolved solids, in pounds; SS, suspended solids, in pounds; TN, total nitrogen, in pounds; TKN, total 

ammonia plus organic nitrogen as nitrogen, in pounds; TP, total phosphorus, in pounds; DP, dissolved phosphorus, in pounds; CD, total-recoverable 

cadmium, in pounds; CU, total-recoverable copper, in pounds; PB, total-recoverable lead, in pounds; ZN, total-recoverable zinc, in pounds; RUN, volume, in 

cubic feet; dashes indicate not available}

Root-mean-square error In log units

Response variable

COD

DS

SS

TN

TKN

TP

DP 

CD5

CU

PB

ZN

RUN

Regional-regression models from Drlver-Tasker 

(1990)

3-varlable model1

0.353

.396

.463

.256

.960

.598

.637 

.409

.666

.668

.421

-

Multlvarlate model2

0.738

.423

3.70

.669

1.11

1.13

1.12 

.626

1.15

.708

.494

.332

Regional-regression models from Ellis snd 

others (1984)

Small drainage basins3

0.421

~

.490

.336

~

.461

~

.782

.517

.375

Small snd large 

drainage bsslns4

0.384

-

.549

.279

.469

.583

.495

.354

'Equations from table 3 in Driver and Tasker (1990). 

2Equations from table 1 in Driver and Tasker (1990). 

'Equations from table 19 in Ellis and others (1984). 

4Equations from table 20 in Ellis and others (1984). 

5Root-mean-square error computed without censored data.

Differences between the observed and estimated 

storm-runoff loads, volume, and event-mean concentrations can be explained by the following:

1. Hydrologic conditions controlling the detection of 

properties and constituents specific to 

Colorado Springs are not explained by the 

Driver and Tasker (1990) models.

2. Data collected for certain properties and constituents for the NURP studies might not be representative of the Colorado Springs area.

3. Regional-regression models were developed using 

a larger range of drainage-basin areas than the 

drainage-basin areas used for this study 

(tables 1 and 6). Therefore, regional-regression models might be biased and might be 

overestimating storm-runoff loads, volume, 

and event-mean concentrations for smaller 

drainage basins.

Procedures for Adjustment of Estimates from 

Single-Storm Regional-Regression Models 

Using Local Data

When compared to observed data, single-storm 

regional-regression models tended to overestimate 

storm-runoff loads, volume, and event-mean concentrations. As a result, single-storm local-regression 

models would be the preferred method for estimating 

storm-runoff loads, volume, and event-mean concentrations because the single-storm local-regression models were developed using local data based on the 

climatic, physical, and land-use characteristics of the 

Colorado Springs area. However, only a small number 

of observations (30~snowmelt samples not included) 

were available for the development of the single-storm 

local-regression models, and the use of the singlestorm local-regression models need to be limited to 

estimates within the ranges of the explanatory variables 

used to develop the model (table 6). Single-storm 

regional-regression models are based on a large number of observations (65 to 348), and the explanatory 

variables have a wider range than the explanatory vari20 Water Quality of Storm Runoff and Comparison of Procedurea for Estimating Storm-Runoff Loads, Volume, EventMean Concentrations, and the Mean Load for a Storm for Selected Properties and Constituents for Colorado Springs, 

Southeastern Colorado, 1992
Table 8. Summary of residual values for observed minus estimated values of storm-runoff loads, volume, and event-mean 

concentrations

[DTl, regional-regression model from table 1 in Driver and Tasker (1990); DT3, regional-regression model from table 3 in Driver and Tasker (1990); EL19, 

regional-regression model from table 19 in Ellis and others (1984); EL20, regional regression model from table 20 in Ellis and others (1984); DTS, regionalregression model from table 5 in Driver and Tasker (1990); load, storm-runoff loads, in pounds; mg/L, storm-runoff event-mean concentration, in milligrams 

per liter; Hg/L, storm-runoff event-mean concentration, in micrograms per liter, dashes indicate not data available; negative number in the table means the 

estimated value from the regional regression model is greater than the observed value; positive number in the table means the estimated value from the 

regional-regression model is less than the observed value]

Response variable

Chemical oxygen demand (COD)

Dissolved solids (DS)

Suspended solids (SS)

Total nitrogen (TN)

Total ammonia plus organic 

nitrogen as nitrogen (TKN)

Total phosphorus (TP)

Dissolved phosphorus (DP)

Regression 

model

DTl load

DT3 load

E119 load

E120 load

DTS mg/L

DTl load

DT3 load

DTS mg/L

DTl load

DT3 load

E119 load

E120 load

DTS mg/L

DTl load

DT3 load

E119 load

E120 load

DTS mg/L

DTl load

DTS load

DTS mg/L

DTl load

DT3 load

El 19 load

E120 load

DTS mg/L

DTl load

DT3 load

DTS mg/L

Minimum

-2,525

-349

^55

-323

-1,275

-85

-124

-126

27

-1,021

-678

-1,019

^89

0.43

.39

.44

.55

.71

-42

-16

-34

-22

-1.9

.04

.04

-8.3

-9.6

-.95

-4.6

Maximum

1,179

1,188

1,138

12,155

265

226

206

49

2,130

1,064

1,396

1,144

702

79

7.09

12.3

9.52

22

1.5

-.72

-1.2

.95

.22

2.6

2.7

.63

.31

.06

.13

Residual values

75th 

percentlle

-1.4

39

44

60

-28

48

36

-7.4

756

148

372

326

193

8.5

2.8

3.9

2.8

12

-1.4

-1.7

-2.3

-0.12

-.13

.91

.92

-.21

-.06

-.12

-.02

Median

-175

-18

6

11

^33

12.4

-0.05

-62

310

-31

36

22

-82

4.0

2.1

2.6

1.9

5.4

-3.8

-4.0

-10

-.60

-.47

.63

.65

-2.4

-.24

-.31

-.75

Mean

-347

16

-13

20

-443

33

18

^8

448

13

159

87

-34

4.7

1.8

2.2

1.9

4.4

-7.6

-5.0

-12

-3.1

-0.60

.72

.74

-3.1

-1.5

-.33

-1.6

PROCEDURES FOR ESTIMATING SINGLE-STORM-RUNOFF LOADS, VOLUME, AND EVENT-MEAN CONCENTRATIONS 21
Table 8. Summary of residual values for observed minus estimated values of storm-runoff loads, volume, and event-mean 

concentrations-Continued

Response variable

Total-recoverable cadmium 

(CD) 1

Total-recoverable copper (CU)

Total-recoverable lead (PB)

Total-recoverable zinc (ZN)

Volume of runoff (RUN)

Regression 

model

DT1 load

DT3 load

DTSjlg/L

DT1 load

DT3 load

DTSjig/l

DT1 load

DT3 load

E119 load

E120 load

DT5jig/L

DT1 load

DTSload

E119 load

E120 load

DT5jig/L

DT1 cubic feet

E119 cubic feet

EL20 cubic feet

Minimum

-0.02

-.002

-2.8

-.77

-.13

-168

-.66

-.62

-1.1

-.35

-315

-.64

-.69

-.87

-.76

- 51

-31,592

^t8,818

-32,342

Maximum

0.001

.002

.71

-.02

.02

-30

.47

.43

.36

'.63

200

1.1

.95

1.0

1.0

869

51,359

35,965

47,411

Residual valuea

75th 

percentile

-0.0002

.0003

-.07

-.06

-.01

-46

.11

-.002

.03

.07

18

.19

.14

.14

.15

-133

4,483

2,417

4,794

Median

-0.0006

-.00006

-.69

-.09

-.03

-77

-.06

-.09

-.11

-.02

-124

-.009

-.007

-.009

-.006

-288

445

138

964

Mean

-0.002

-.0003

-.82

-.15

-.03

-82

-.08

-.12

-.21

-.003

-90

.02

.03

-.04

-.01

-238

1,439

-4,928

1,028

'Computed using uncensored data.

ables used in the single-storm local-regression models 

(table 6). It would be useful if single-storm local- and 

regional-regression models could be combined to take 

advantage of the strengths of both regression models 

while minimizing the respective deficiencies of the 

regression models.

Hoos (1991) presented a procedure to adjust 

single-storm regional-regression models using local 

data. Hoos and Sisolak (1993) evaluated different 

model-adjustment procedures (MAP's) and established 

criteria for selecting the appropriate MAP. The MAP is 

in the form of a regression analysis. Local data are used 

as the calibration data set. In one MAP (MAP-R-P), 

log-transformed local (observed) data (response variables) are regressed against the log-transformed estimates from the single-storm regional-regression models 

(explanatory variables). The resulting equations are the 

adjusted regression models used to predict storm-runoff 

loads, volume, or event-mean concentrations at an 

unmonitored site. Another form of MAP (MAP-W) is 

simply the weighting of log-transformed estimates from

local- and regional-regression models. The equations 

for the two MAPs for adjusting the regional-regression 

equations are Hoos. and Sisolak, (1993): 

1. MAP-R-P calibration equation:

logO,. = log ! log REi (7)

where

O,- = the observed value of storm-runoff load, 

volume, or event-mean concentration at 

site i;

B0 and Bj = coefficients fitted from a simple linearregression analysis of the calibration data 

set 

(observed data); and

RE,- = the regional estimate; estimated value of 

storm-runoff load, runoff volume, or 

event-mean

concentration from the unadjusted singlestorm regional-regression model at site j.

22 Water Quality of Storm Runoff and Comparison of Procedures for Estimating Storm-Runoff Loads, Volume, EventMean Concentrations, and the Mean Load for a Storm for Selected Properties and Constituents for Colorado Springs, 

Southeastern Colorado, 1992
The adjusted regional-regression model (from 

the detransformation of eq. 7) is then:

AREi = Bl (BCF) (8)

where

= the adjusted single-storm regionalregression estimate. 

2. MAP-W calibration equation:

log O. = { (J x logRE) [ (1-J) x logLOC] } (9)

where

J = { (SEloc 2)/[(SEloc2 ) + (SEreg2) ] } (10)

where

SEloc = the standard error of estimate, in log units 

for the single-storm local-regression 

model;

SEreg = the standard error of estimate, in log units 

as reported in Driver and Tasker (1990) 

for the single-storm regional-regression 

model; and

LOG = estimated value from the single-storm

local-regression equation. 

The weighted single-storm regional-regression 

model (the detransformation of eq. 10) then is:

WE = { (REJ) x (LOC (1 "J) )} xBCF, (11) 

where

WE = adjusted (weighted) single-storm regionalregression estimate.

Selection of the appropriate MAP needs to be 

made based on whether or not observed and estimated 

data are correlated and on if there is a consistent bias 

between the local-data (observed) and estimated-data 

pairs (fig. 2, step 3). Correlation between observed and 

estimated data was evaluated by analyzing the significance of Spearman's rho (Iman and Conover, 1983), 

and bias was determined using the signed-rank test on 

the paired data (Iman and Conover, 1983). If the null 

hypothesis (a significant correlation does not exist 

between observed and estimated values or a consistent 

bias does not exist between observed and estimated 

values) for either test is not rejected at a selected level 

of significance, then correlation between observed data 

and explanatory variables is determined by examining

correlation coefficients, r2 (fig. 2, step 4) (Hoos and 

Sisolak, 1993).

After evaluating Spearman's rho and the signedrank test for the Colorado Springs data set, the appropriate MAPs were selected for adjusting the regionalregression models using local data based on the flow 

chart in figure 2. The RMSE was large for all comparisons between observed values and values estimated 

using single-storm regional-regression equations 

(tables 7,9, and 10). Because observed values and estimated values from single-storm regional-regression 

equations were highly correlated and had a consistent 

direction of bias, MAP-R-P (fig. 2, steps 2 and 3) was 

selected for adjusting storm-runoff-load equations for 

TN, TKN, TP, DP, CU, and PB and for adjusting the 

storm-runoff event-mean concentration equations for 

TP, CU, and PB. Observed and estimated values for the 

remaining storm-runoff loads and event-mean concentrations of the remaining constituents were not highly 

correlated or did not have a consistent direction of bias, 

or both; however, the remaining observed values were 

significantly correlated with some explanatory variables. Therefore, MAP-W (fig. 2, step 3) was selected 

for adjusting storm-runoff-load equations for COD, 

DS, SS, CD, and ZN; for adjusting equations for estimating volume of runoff; and for adjusting event-mean 

concentration equations for COD, DS, SS, TN, TKN, 

DP, CD, and ZN.

When compared to observed storm-runoff loads 

and volume, the three-variable single-storm regionalregression models for storm-runoff loads and the multivariate single-storm regional-regression models for 

storm-runoff volume that were developed by Driver 

and Tasker (1990) had the smallest RMSE of all of the 

single-storm regional-regression models tested. These 

models and the 13-variable single-storm regionalregression models for event-mean concentration were 

adjusted using MAPs.

The MAP's decreased model error in estimating 

storm-runoff loads, volume, and event-mean concentrations, except for the equation for event-mean concentration for CD. Reduction of error, in percent, 

ranged from -1,980 to -10 percent (based on data in 

tables 9 and 10). The effect of MAP's on estimated 

storm-runoff loads and event-mean concentrations can 

be illustrated by plotting observed values, estimates 

from regional-regression models, and estimates from 

regional-regression models adjusted using MAPs. Two 

examples from site 2 are presented, one for each 

MAP MAP-R-P (TP) and MAP-W (TKN) (figs. 3 

and 4). In both cases, the estimates of storm-runoff 

load and event-mean concentration obtained using 

MAP-R-P (fig. 3) and MAP-W (fig. 4) were closer to 

the observed value than the estimate from the regionalregression equation. Adjusted models, developed 

using MAP-R-P and MAP W, for estimating stormrunoff loads, volume, and event-mean concentrations 

are listed in tables 11 and 12.

PROCEDURES FOR ESTIMATING SINGLE-STORM-RUNOFF LOADS, VOLUME, AND EVENT-MEAN CONCENTRATIONS 23
STEP1

STEP 2

Are observed value

and regional-regression

estimate highly

correlated?

YES

STEPS

YES

NO

STEP 4

Are observed 

values and e

variables highly 

correlated?

YES

NO

Use

regional 

model 

as is

Use single factor 

regression on the 

estimated value 

from the singlestorm regionalregression model 

(MAP-R-P)

Use weighted 

combination of 

estimates from 

regional and 

local singlestorm regressionmodels (MAP-W)

Use simple estimator

(for example, MEAN)

or collect additional

data to callibrate a

local regression model

Figure 2. Flowchart for selection of model adjustment procedures (modified from Hoos and Sisolak, 1993).

24 Water Quality of Storm Runoff and Comparison of Procedures for Estimating Storm-Runoff Loads, Volume, EventMean Concentrations, and the Mean Load for a Storm for Selected Properties and Constituents for Colorado Springs, 

Southeastern Colorado, 1992
Table 9. Effect of model-adjustment procedures on root-mean-square error and standard error of estimate for storm-runoff 

loads and volume

[MAP-R-P, observed data regressed against the regional estimate; MAP-W, the weighted combination of local-regression estimate and regional-regression 

estimate; COD, chemical oxygen demand; DS, dissolved solids; SS, suspended solids; TN, total nitrogen; TKN, total ammonia pins organic nitrogen as 

nitrogen; TP, total phosphorus; DP, dissolved phosphorus; CD, total-recoverable cadmium; CU, total-recoverable copper; PB, total-recoverable lead; 

ZN, total-recoverable zinc; RUN, volume; dashes indicate no data]

Root-mean-square error

Response 

variable

COD

DS

SS

TN

TKN

TP

DP

CD3

CU

PB

ZN

RUN

Regional-regression model from Drlver-Tasker (1990)

3-varlable models1

(percent)

97

114

145

68

1,147

238

276

119

308

311

125

-

(log units)

0.353

.396

.463

.256

.960

.598

.637

.409

.666

.668

.421

-

13-varlable models2

(percent) (log units) (percent)

-

_

19

106

109

95

_

116

191

..

89 .332

Standard error of estimate

P-R-P

(log units)

-

0.283

.377

.384

.348

.402

.538

-

-

MAP-W

(percent)

65

59

102

-

-

-

~

81

-

115

29

(log units)

0.258

.237

.366

-

-

~

.308

-

-

.398

.124

'Equations from table 3 in Driver and Tasker (1990). 

Equations from table 1 in Driver and Tasker (1990). 

3Computed without censored data.

Table 10. Effect of model-adjustment procedures on standard error of estimate for storm-runoff event-mean concentrations

[MAP-R-P, local data regressed against the regional estimate; MAP-W, the weighted combination of local-regression estimate and regional-regression 

estimate; COD, chemical oxygen demand; DS, dissolved solids; SS, suspended solids; TN, total nitrogen; TKN, total ammonia plus organic nitrogen as 

nitrogen; TP, total phosphorus; DP, dissolved phosphorus; CD, total-recoverable cadmium; CU, total-recoverable copper, PB, total-recoverable lead; 

ZN, total-recoverable zinc; dashes indicate not applicable]

Root-mean-square error

Response 

variable

COD

DS

SS

TN

TKN

TP

DP

CD2

CU

PB

ZN

1 Reglonel-regresslon model from 

Driver and Tasker (1990)

(percent)

201

69

74

282

2,078

1,398

1,220

86

459

186

121

(log units)

0.553

.272

.286

.643

1.07

.998

.972

.322

.764

.531

.413

Standard error of estimate

MAP-R-P MAP-W

(percent) (log units) (percent)

41

45

 64

40

98

73 0.285

176

238

54 .219

70 .273

44

(log units)

0.172

.188

.253

.168

.356

-

.516

.598

-

.183

'Equations from table 5 in Driver and Tasker (1990). 

2Computed without censored data.

PROCEDURES FOR ESTIMATING SINGLE-STORM-RUNOFF LOADS, VOLUME, AND EVENT-MEAN CONCENTRATIONS 25
Q 

Z 1

2

? 0.5 

Q

0.2

0.1

cc 

O 

I 

t/3 

O

Q.

< 0.05 -

0.02 -

0.01

May

+ 

D

D

D

June

1992 

DATE

July

D

+ D

August

EXPLANATION

+ OBSERVED TOTAL PHOSPHORUS LOAD

X ESTIMATED TOTAL PHOSPHORUS LOAD

D ADJUSTED ESTIMATED TOTAL PHOSPHORUS LOAD

Figure 3. Observed total-phosphorus, estimated total-phosphorus, and adjusted estimates of total-phosphorus 

loads for storm-runoff load at site 2.

26 Water Quality of Storm Runoff and Comparison of Procedures for Estimating Storm-Runoff Loada, Volume, EventMean Concentrations, and the Mean Load for a Storm for Selected Properties and Constituents for Colorado Springs, 

Southeastern Colorado, 1992
O

cc

to

50

20

10

UJ CC

CD HI c

O t 5

CC _l

t CC z s

a w

11 2 CC =

o 2

3 I ' °- -r

O 

<

0.5 -

0.2 -

0.1

D

May

+ 

n

D

l

June July

D

D

August

1992 

DATE

EXPLANATION

+ OBSERVED TOTAL AMMONIA PLUS ORGANIC NITROGEN AS NITROGEN 

X ESTIMATED TOTAL AMMONIA PLUS ORGANIC NITROGEN AS NITROGEN 

D ADJUSTED ESTIMATES TOTAL AMMONIA PLUS ORGANIC NITROGEN AS NITROGEN

Figure 4. Observed total ammonia plus organic nitrogen as nitrogen, estimated total ammonia plus organic 

nitrogen as nitrogen, and adjusted estimates of total ammonia plus organic nitrogen as nitrogen for storm-runoff 

event-mean concentrations at site 2.

PROCEDURES FOR ESTIMATING SINGLE-STORM-RUNOFF LOADS, VOLUME, AND EVENT-MEAN CONCENTRATIONS 27
Table 11. Summary of adjusted models for storm-runoff loads and volume

[MAP-R-P, regression of observed data against regional-regression; MAP-W, weighted combination of local-regression estimate and regional-regression 

estimate; Bo, B1, coefficients fitted from a simple linear regression analysis of the calibration data set (local data base); BCF, the bias correction factor; 

J, weighting factor; COD, chemical oxygen demand loads; DS, dissolved-solids load; SS, suspended-solids load; TN, total nitrogen load; TKN, total 

ammonia plus organic nitrogen load; TP, total phosphorus load; DP, dissolved phosphorus load; CD, total-recoverable cadmium load; CU, total-recoverable 

copper load; PB, total-recoverable lead load; ZN, total-recoverable zinc load; RUN, storm-runoff volume; dashes indicate not applicable; y, response 

variable; RE, estimate from regional regression; LOG, estimate from local regression]

Response 

variable

COD

DS

SS

TN

TKN

TP

DP

CD

CU

PB

ZN

RUN

Model-adjustment procedure

Bo

-

-

0.82

.23

.33

.24

.14

.20

-

MAP-R-P1

B1

-

-

0.71

.61

.91

.82

.77

.69

-

BCF

-

-

1.23

1.40

1.35

1.32

1.42

1.80

-

J

0.27

.35

.23

-

-

-

.85

-

-

.42

.24

MAP-W2

1-J

0.73

.65

.77

-

-

-

.15

-

-

.58

.76

BCF

1.13

1.14

1.24

-

-

-

1.14

-

-

1.18

1.04

'Form of equation is y = BoRBBIBCF.

2Form of equation is y = (REG1) (LOG (I^ BCF.

Table 12. Summary of adjusted models for storm-runoff event-mean concentrations

[MAP-R-P, regression of local data against regional estimate; MAP-W, weighted combination of local-regression estimate and regional-regression estimate; 

Bo, B1, coefficients fitted from a simple linear regression analysis of the calibration data set (local data base); BCF, bias correction factor, J, weighting factor; 

COD, chemical oxygen demand event-mean concentration; DS, dissolved-solids event-mean concentration; SS, suspended-solids event-mean concentration; 

TN, total nitrogen event-mean concentration; TKN, total ammonia plus organic nitrogen event-mean concentration; TP, total phosphorus event-mean 

concentration; DP, dissolved phosphorus event-mean concentration; CD, total-recoverable cadmium event-mean concentration; CU, total-recoverable copper 

event-mean concentration; PB, total-recoverable lead event-mean concentration; ZN, total-recoverable zinc event-mean concentration; dashes indicate not 

applicable; y, response variable; RE, estimate from regional model; LOG, estimate from local model]

Response 

variable

Bo

COD

DS

SS

TN

TKN

TP 0.48

DP

CD

CU 1.52

PB 886,692

ZN

Model-adjustment procedure

MAP-R-P1

B1

-

-

-

-

-0.26

-

.54

-1.69

-

BCP

-

-

-

-

1.2

-

1.16

1.18

-

J

0.33

.18

.24

.33

.28

-

.22

.78

-

.25

MAP-W2

1-J

0.67

.82

.76

.67

.72

-

.78

.22

-

.75

BCF

1.08

1.05

1.14

1.07

1.06

1.10

1.05

--

1.08

'Form of equation is y = Bo x REG81 BCF. 

2Form of equation is y = (REJ) (LOG)*1 * BCF.

28 Water Quality of Storm Runoff and Comparison of Procedures for Estimating Storm-Runoff Loads, Volume, EventMean Concentrations, and the Mean Load for a Storm for Selected Properties and Conatituents for Colorado Springs, 

Southeastern Colorado, 1992
ESTIMATES OF A MEAN LOAD FOR A 

STORM

In addition to developing single-storm regionalregression models for storm-runoff loads, volume, and 

event-mean concentrations, Driver and Tasker (1990) 

developed regression models for estimating the mean 

load for a storm, hereafter called mean load. Mean load 

is the estimate of mean load for a particular drainage 

basin. With the estimate of mean load, seasonal or 

annual loads for a particular drainage basin can be estimated by multiplying the mean load by the average 

number of storms for the season or year. Regression 

models for estimating mean load were based on drainage-basin area, percent of impervious area, mean 

annual rainfall, mean minimum January temperature, 

and a variable (dummy variable) indicating whether 

commercial and industrial land uses exceeded or did 

not exceed 75 percent of the drainage-basin area 

(Driver and Tasker, 1990). Regression models for estimating mean load were developed for COD, DS, SS, 

TN, TKN, TP, DP, CU, PB, and ZN. These regression 

models were developed from the NURP data base and 

are based on rain storms. The range of explanatory 

variables used in the regression models for estimating 

mean load are listed in table 13. In general, use of the 

models to estimate mean load at sites that have characteristics much beyond the range of values listed in

table 13 need to be avoided (Driver and Tasker, 1990). 

Using the Driver and Tasker (1990) models, mean 

loads were estimated for COD, DS, SS, TN, TKN, 

TP, DP, CU, PB, and ZN for sites 1 through 5. A 

90-percent confidence interval was computed for each 

mean load of a storm estimated using the models from 

Driver and Tasker (1990) (table 14). For example, 

there is a 90-percent confidence level that the true mean 

load for TP for all storms at site 1 lies between 0.06 and 

0.87 Ib (table 14). Confidence intervals were not computed for single-storm regression models because 

matrix information was unavailable.

Estimated mean loads from the Driver and 

Tasker (1990) models (MLDT) were compared to 

mean loads estimated for 1992, based on daily mean 

water discharge and land-use characteristics, hereafter 

referred to as MLDWD, and on loads that are the mean 

storm-runoff load of the six storms sampled at each of 

the five sites in 1992 (table 14).

Linear regression was used for estimating mean 

loads based on daily mean water discharge. The most 

suitable regression models for estimating mean load 

from daily mean water discharge were selected using 

the procedures described in the section "Single-Storm

Local-Regression Models." Values of r2 ranged from 

0.59 to 0.84, and standard error of estimate, in percent, 

for the regression models, ranged from 45 to 93 

(table 15).

Table 13. Ranges of values of explanatory variables used in development of regression models for mean load for a storm 

(modified from Driver and Tasker, 1990)

[DA, total contributing drainage area; LA, impervious area; MAR, mean annual rainfall; MJT, mean minimum January temperature; COD, chemical oxygen 

demand; DS, dissolved solids; SS, suspended solids; TN, total nitrogen; TKN, total ammonia plus organic nitrogen as nitrogen; TP, total phosphorus; DP, 

dissolved phosphorus; CU, total-recoverable copper; PB, total-recoverable lead; ZN, total-recoverable zinc]

Response variable 

(mean seasonal 

or mean annual

Explanatory variables

DA 

(square mllea)

IA 

(percent)

MAR 

(Inches)

MJT 

(degrees Fahrenheit)

loaaj

COD

DS

SS

TN

TKN

TP

DP

CU

PB

ZN

Minimum

0.019

.020

.019

.019

.019

.019

.020

.014

.019

.019

Maximum

0.707

.450

.707

.830

.707

.830

.707

.830

.830

.830

Minimum

4

19

4

4

4

4

4

6

4

13

Maximum

100

99

100

100

100

100

99

99

100

100

Minimum

8.38

10.24

8.38

11.83

8.38

8.38

8.38

8.38

8.38

8.38

Maximum

62.00

37.61

49.38

62.00

62.00

62.00

46.18

62.00

62.00

62.00

Minimum

3.2

11.4

3.2

3.2

3.2

3.2

10.8

15.3

3.2

11.4

Maximum

58.7

35.8

50.1

58.7

58.7

58.7

35.8

58.7

58.7

58.7

ESTIMATES OF A MEAN LOAD FOR A STORM 29
Table 14. Comparison of computed mean load for a storm based on daily mean water discharge and land-use characteristics, 

estimated mean load for a storm, and average of samples collected during rainfall runoff

(MLDWD, mean load estimated based on daily mean water discharge and land-use characteristics; MLDT, estimated mean load, from Driver and Tasker 

(1990) models; CI, 90-percent confidence interval; n, number of stonns occurring as rain, January through December 1992; COD, chemical oxygen demand; 

DS, dissolved solids; SS, suspended solids; TN, total nitrogen; TKN, total ammonia plus organic nitrogen as nitrogen; TP, total phosphorus; 

DP, dissolved phosphorus; CU, total-recoverable copper; PB, total-recoverable lead; ZN, total-recoverable zinc]

Response 

variable 

(as load)

Mean load of a storm 

(pounds)

MLDWD

MLDT 

Regression models In Drivar and Tasker (1990)

Estimated Lower CI Upper CI

Mean of six storms 

In 1992 

(pounds)

Sixteenth Hole, Valley-Hi Golf Course 

Sitel 

n-54

COD

DS

SS

TN

TKN

TP

DP

CU

PB

ZN

756

232

927

4.3

2.4

0.73

.28

.03

.54

.57

172

294

168

6.63

2.16

0.31

.20

.12

.28

.42

41

58

18.2

1.24

0.43

.06

.03

.02

.05

.09

430

947

666

19.5

6.68

0.87

.60

.38

.84

1.11

492

201

716

3.7

2.3

0.71

.24

.03

.27

.49

Chestnut Street at Douglas Creek 

Site 2 

n-48

COD

DS

SS

TN

TKN

TP

DP

CU

PB

ZN

523

77

1,349

1.9

.90

.33

.14

.07

.36

1.42

172

400

203

6.04

1.94

.40

.23

.15

.25

.39

41

77

22.1

1.15

.38

.08

.04

.02

.04

.08

430

1,330

809

17.6

6.11

1.12

.72

.47

.77

1.02

217

60

603

1.3

.76

.21

.10

.04

.24

.76

Beacon Street at Buchanan Street 

Site 3 

n-50

COD

DS

SS

TN

TKN

TP

DP

CU

PB

ZN

30 Water Oualitv <

312

71

433

2.0

0.80

.26

.17

.02

.19

.24

>f Storm Runoff and Co

223

424

210

2.9

0.97

.42

.24

.16

.35

.55 

moarlson of Procedures for E

53

81

22.9

0.49

.16

.09

.04

.03

.06

.12 

Btlmatlna Storm560

1,410

837

9.7

3.66

1.17

.74

.49

1.07

1.43 

 Runoff Loads. Volum

92

37

107

1.2

0.40

.16

.12

.007

.03

.12 

a. EventMaan Concentrations, and the Mean Load for a Storm for Selected Properties and Constituents for Colorado Springs, 

Southeastern Colorado, 1992
Table 14. Comparison of computed mean load for a storm based on daily mean water discharge and land-use 

characteristics, estimated mean load for a storm, and average of samples collected during rainfall runoff-Continued

Response

variable 

(as load) MLDWD

Mean load of a atorm 

(pounds) Mean of six storms

MLDT In 1992 

Regression models In Driver and Taeker (1 990) (pounds)

Estimated Lower Cl Upper Cl

Wahsatch Street at Cross Lane 

Site 4

COD 465

DS 117

SS 929

TN 4.7

TKN .74

TP 1.22

DP .36

CU .02

PB .31

ZN .31

COD 339

DS 45

SS 407

TN 0.89

TKN .65

TP .20

DP .09

CU .01

PB .12

ZN .20

n-50

357

1,060

372

10.8

3.42

.88

.40

.30

.54

.80

Walmart at Eighth Street 

SiteS

n-51

76

136

103

3.12

1.02

.16

.13

.07

.12

.17

83.3

173

39.7

2.01

.66

.18

.06

.05

.09

.17

18

27

11.1

0.58

.19

.03

.02

.01

.02

.04

906

4,140

1,510

31.9

10.9

2.5

1.32

.95

1.67

2.13

190

432

416

9.22

3.26

0.46

.40

.22

.36

.45

378

140

747

5.2

.76

1.20

.46

.02

.14

.31

58

26

237

0.64

.27

.15

.05

.005

.06

.11

Table 15. Summary of r2 values and standard error of estimate for regression models used to estimate 

mean load, in pounds, of a storm based on daily mean water discharge and land-use characteristics

[r2, is the coefficient of determination]

Response variable

Chemical oxygen demand

Dissolved solids

Suspended solids

Total nitrogen

Total ammonia plus organic nitrogen

Total phosphorus

Dissolved phosphorus

Total-recoverable copper

Total-recoverable lead

Total-recoverable zinc

r2

0.75

.82

.68

.81

.78

.75

.59

.84

.65

.81

Standard error of estimate

Percent

57

45

83

47

47

66

81

49

93

55

Log units

0.229

.188

.313

.195

.193

.262

.308

.200

.344

.225

ESTIMATES OF A MEAN LOAD FOR A STORM 31
Records of daily mean water discharge were collected at all sites from about June 1 to December 6, 

1992. For periods of missing record, daily mean water 

discharge was estimated using the following equation:

DMWD = 19,941TRN1 -08LUI-1 -26LUC-°-98

LUR-l.78 1>25 (12)

where

DMWD = daily mean water discharge, in cubic feet

per second;

TRN = total rainfall, in inches; 

LUI = industrial land use, in percent; 

LUC = commercial land use, in percent; and 

LUR = residential land use in percent.

For this equation, the value of r2 was 0.77, and 

the standard error of estimate was 78 percent.

Generally, MLDWD were within the 90-percent 

confidence intervals of MLDT (table 14). However, 

estimates of COD, DS, SS, and CU, at selected sites 

were not within the 90-percent confidence intervals 

from Driver and Tasker (1990) mean load equations. 

At sites 1, 2, and 5, estimates of MLDWD for COD 

exceeded the upper 90-percent confidence interval 

(table 14); and at sites 1 and 2, MLDWD for SS 

exceeded the upper 90-percent confidence limit 

(table 14). At sites 3 and 4, estimates of MLDWD for 

DS and CU were less than the 90-percent confidence 

interval, and at site 2, estimates of mean load based on 

daily mean water discharge for ZN exceeded the upper 

90-percent confidence interval (table 14).

At all sites, estimates of MLDWD for COD and 

SS were larger than MLDT (table 14). At all sites, estimates of MLDWD for DS, TN, and CU were less than 

MLDT (table 14). Estimates of MLDWD for TKN, TP, 

DP, PB, and ZN based on daily mean water discharge 

when compared to MLDT had no consistent direction 

of bias (table 14).

Differences between the two types of estimates 

of mean load may be explained by the following:

1. Hydrologic conditions controlling the occurrence 

of properties and constituents, especially COD 

and SS, that are specific to Colorado Springs 

are not accounted for in the Driver and Tasker 

(1990) models.

2. Data collected for certain properties and constituents for the NURP studies may not be representative of the Colorado Springs area.

Generally, the mean load of six storms at each 

site was within the 90-percent confidence interval of 

the Driver and Tasker (1990) mean load equations 

(table 14). The mean load of the six storms exceeded

the upper 90-percent confidence interval for COD and 

SS at site 1 (table 14). The mean load of the six storms 

was less than the lower 90-percent confidence interval 

for DS at sites 2,3,4, and 5; for CU at sites 3,4, and 5; 

and for PB at site 3 (table 14).

The mean load of the six storms at each site compared well with the estimates derived using the Driver 

and Tasker (1990) mean load equations. However, 

these mean loads represent only 6 storms, whereas the 

Driver and Tasker (1990) models were developed using 

between 200 and 1,000 storms that represent drainage 

basins having a wider range of drainage-basin area and 

percent impervious area (table 6). Therefore, the 

Driver and Tasker (1990) mean load equations might 

provide a better estimate of annual and seasonal loads 

for ungaged drainage basins in Colorado Springs.

COMPARISON OF PROCEDURES FOR 

ESTIMATING STORM-RUNOFF LOADS, 

VOLUMES, EVENT-MEAN 

CONCENTRATIONS, AND THE MEAN 

LOAD FOR A STORM

Various procedures for estimating storm-runoff 

loads, volume, and event-mean concentrations have 

been discussed in this report. The following is a more 

concise comparison of the value and limitations of 

these procedures. The procedures discussed include:

1. Single-storm local-regression models for stormrunoff loads, volume, and event-mean concentration (tables 4 and 5).

2. Single-storm regional-regression models for

storm-runoff loads, volume, and event-mean 

concentration (Ellis and others, 1984; 

Driver and Tasker, 1990).

3. Adjustment of single-storm regional-regression 

models for storm-runoff loads, volume, and 

event-mean concentration using local data 

(tables 11 and 12) (Hoos and Sisolak, 1993).

4. Estimates of mean load (table 14).

The use of single-storm local-regression models 

needs to be limited to the ranges of explanatory variables (table 6) used to develop the model. If values outside these ranges are used in the single-storm localregression models, the standard errors may be considerably larger than the values reported in tables 4 and 5. 

As the single-storm local-regression models are 

applied to drainage-basin areas and to storm volumes 

larger than the values from the observation sites, the 

accuracy of estimates of storm-runoff loads, volume, 

and event-mean concentrations decreases.

32 Water Quality of Storm Runoff and Comparison of Procedures for Estimating Storm-Runoff Loads, Voluma, EventMean Concentrations, and the Mean Load for a Storm for Selected Properties and Conetltuents for Colorado Springs, 

Southeastern Colorado, 1992
Single-storm regional-regression models were 

developed using explanatory variables that have a 

wider range than the single-storm local-regression 

models (table 6). When compared to observed data, 

single-storm regional-regression models tended to 

overestimate storm-runoff loads, volumes, and eventmean concentrations (table 8). Model adjustment procedures (MAPs), which use local data to decrease the 

model error, were applied to selected single-storm 

regional-regression models. The MAPs decreased 

model error in estimating storm-runoff loads, volume, 

and event-mean concentrations model error 

decreased from -1,980 to -10 percent (based on data in 

tables 9 and 10).

A prediction of annual or seasonal storm-runoff 

loads, volume, and event-mean concentration at an 

unmonitored site can be obtained by applying the 

single-storm models described to a series of storms and 

producing a synthetic record of storm loads and volume. Values of storm characteristics used as explanatory variables listed in table 6 and in Ellis and others 

(1984) and Driver and Tasker (1990) may be determined for a series of storms from the long-term rainfall 

record for a station near an unmonitored site. The synthesized record of storm loads may be reduced to an 

estimate of mean annual or mean seasonal load by summing loads from each storm, then dividing by the number of years in the period of the synthetic record.

The mean load estimated for individual sites for 

selected constituents generally compared well to mean 

load estimated based on daily mean water discharge 

and land-use characteristics and to the mean load of six 

storms, for each site, sampled in 1992 (table 14). The 

use of the mean load procedure should be limited to the 

range of values of variables used to develop the models 

(table 13). However, the mean load procedure can be 

applied to larger drainage basins by dividing the drainage basin into segments that fall into the range of drainage-basin areas used to develop the mean load model 

and computing the mean load for each drainage-basin 

segment. The mean load for the drainage basin would 

be the sum of the loads computed for each drainagebasin segment. Annual or seasonal loads could be 

computed by multiplying the estimated mean load by 

the average, or total for a specific year, number of 

storms for a drainage basin.

SUMMARY

The U.S. Environmental Protection Agency 

requires that municipalities that have a population of 

100,000 or greater obtain National Pollutant Discharge 

Elimination System permits to control the quality of 

storm runoff. In 1992, the U.S. Geological Survey, in 

cooperation with the Colorado Springs City Engineering Division, began a study to characterize the water 

quality of storm runoff and to compare techniques for 

the estimation of storm-runoff loads, volume, and 

event-mean concentrations for selected properties and 

constituents.

Precipitation, streamflow, and water-quality data 

were collected during 1992 at five sites in Colorado 

Springs. Thirty-five samples were collected, seven at 

each of the five sites. At each site, three samples were 

collected for National Pollutant Discharge Elimination 

System permitting purposes; two of the samples were 

collected during rainfall runoff, and one sample was 

collected during snowmelt runoff. Four additional 

samples were collected at each site to obtain a large 

enough sample size to estimate storm-runoff loads, 

volume, and event-mean concentrations for selected 

properties and constituents using linear-regression procedures developed using data from the Nationwide 

Urban Runoff Program (NURP). Storm-water samples 

were analyzed for as many as 186 properties and constituents. Some of the properties and constituents measured include pH, specific conductance, water 

temperature, chemical oxygen demand, biochemical 

oxygen demand, bacteria, dissolved and suspended solids, major ions, nutrients, residual chlorine, totalrecoverable metals, oil and grease, phenols, volatileorganic compounds, acid-base/neutral organic compounds and pesticides.

Storm runoff sampled had large concentrations 

of chemical oxygen demand and 5-day biochemical 

oxygen demand. Chemical oxygen demand ranged 

from 100 to 830 mg/L, and 5-day biochemical oxygen 

demand ranged from 14 to 260 mg/L. Total-organic 

carbon concentrations ranged from 18 to 240 mg/L. 

The total-recoverable metals lead and zinc had the 

largest concentrations of the total-recoverable metals 

analyzed. Concentrations of lead ranged from 23 to 

350 flg/L, and concentrations of zinc ranged from 

110tol,400|lg/L.

Single-storm local-regression models for estimating storm-runoff loads, volume, and event-mean 

concentrations were developed. Results from these 

models and observed values for storm-runoff loads, 

volume, and event-mean concentrations are compared 

with the results from regional-regression models developed from the Nationwide Urban Runoff Program for 

the purposes of determining which regression models 

provide the best estimates of storm-runoff loads, volume, and event-mean concentrations.

Single-storm local-regression models were 

developed for estimating storm-runoff loads and eventmean concentrations for the 12 National Pollutant Discharge Elimination System properties and constituents 

and for estimating storm-runoff volume. The data for

SUMMARY 33
30 storms representing rainfall runoff from 5 drainage 

basins were used in this analysis. Except for totalrecoverable cadmium, the models were developed 

using ordinary least-squares regression. Because some 

cadmium concentrations were censored (less than values), tobit regression, which is similar to ordinary leastsquares regression, was used to estimate storm-runoff 

load and event-mean concentration for total-recoverable cadmium. The response variables, which are 

storm-runoff loads, volume, and event-mean concentrations, were modeled using climatic, physical, and 

land-use characteristics.

The values of r2 for models that use ordinary 

least-squares regression ranged from 0.57 to 0.86 for 

storm-runoff loads and volume and from 0.25 to 0.63 

for storm-runoff event-mean concentrations. Standard 

errors of estimate ranged from 43 to 115 percent for 

storm-runoff loads and volume and from 32 to 66 percent for storm-runoff event-mean concentrations. 

Standard errors of estimate for storm-runoff load 

and event-mean concentration for total-recoverable 

cadmium were 247 and 171 percent.

Single-storm linear-regression models for estimating storm-runoff loads, volume, and event-mean 

concentrations were developed for 11 of the 12 properties and constituents required for the National Pollutant 

Discharge Elimination System permitting process. 

Regional-regression equations for BOD were not 

developed. Linear-regression equations were developed from data collected by the NURP. Equations were 

developed from the NURP data base and include sets of 

equations for three geographically distinct regions 

delineated by mean annual rainfall. The Colorado 

Springs area is included in Region I. Estimates from 

these regression models were compared with observed 

storm-runoff loads, volume, and event-mean concentrations from samples collected in the study area.

Single-storm regional-regression models tended 

to overestimate storm-runoff loads, volume, and eventmean concentrations observed at the five Colorado 

Springs sites. Because regression models developed 

using local data are based on the climatic, physical, and 

land-use characteristics of the Colorado Springs area, 

single-storm local-regression models would be the 

preferred method for estimating storm-runoff loads, 

volume, and event-mean concentrations. As a result, 

single-storm local-regression models would be the 

preferred method for estimating storm-runoff loads, 

volume, and event-mean concentrations because the 

single-storm local-regression models were developed 

using local data based on the climatic, physical, and 

land-use characteristics of the Colorado Springs area. 

However, only a small number of observations (30) 

were available for the development of the single-storm

local-regression models, and the use of the singlestorm local-regression models needs to be limited to 

estimations within the ranges of the explanatory variables used to develop the model. Although the singlestorm regional-regression models tended to overestimate storm-runoff loads, volume, and event-mean concentrations, these single-storm regional-regression 

models are based on a large number of observations 

(65 to 348), and the explanatory variables have a wider 

range than the explanatory variables used in the singlestorm local-regression models. Single-storm local- and 

regional-regression models were combined using 

model-adjustment procedures to take advantage of the 

strengths of both models while minimizing the respective deficiencies of the models.

When compared to observed storm-runoff loads 

and volume, the adjusted three-variable single-storm 

regional-regression models for storm-runoff loads and 

the multivariate regional-regression model for volume 

of runoff had the smallest root-mean-squared error of 

all of the single-storm regional-regression models 

tested. These models and the single-storm regionalregression models for event-mean concentration were 

adjusted using model-adjustment procedures.

Except for the equation for event-mean concentration of total-recoverable cadmium, all modeladjustment procedures decreased the error for models 

estimating storm-runoff loads, volume, and eventmean concentrations. Reduction of standard error, in 

percent, ranged from -1,980 to -10 percent.

In addition to developing single-storm regionalregression models for storm-runoff loads, volume, and 

event-mean concentrations, regression models for estimating mean load for a storm were developed for ten of 

the National Pollutant Discharge Elimination System 

properties and constituents. With the estimate of the 

mean load, seasonal or annual loads can be estimated 

by multiplying the mean load by the mean number of 

storms for the season or year. These regression models 

were developed from the NURP data base and are 

based on rain storms.

Mean loads were estimated for ten of the 

National Pollutant Discharge Elimination System 

properties and constituents for sites 1 through 5. Estimated mean loads from the regional-regression equations were compared to mean loads estimated for 1992, 

based on daily mean water discharge, and on loads that 

are the mean storm-runoff load of the six storms sampled at each of the five sites in 1992.

Except for selected estimates of chemical oxygen demand, dissolved solids, suspended solids, and 

total-recoverable copper, mean loads based on daily 

mean water discharge were within the 90-percent confidence interval of results from the mean load equa34 Water Quality of Storm Runoff and Comparison of Procedures for Estimating Storm-Runoff Loads, Volume, EventMean Concentrations, and the Mean Load for a Storm for Selected Properties and Constituents for Colorado Springs, 

Southeastern Colorado, 1992
tions. At sites 1,2, and 5, estimates of mean load based 

on daily mean water discharge for chemical oxygen 

demand, and at sites 1 and 2, estimates of mean load 

based on daily mean water discharge for suspended solids exceeded the upper 90-percent confidence intervals. 

At sites 3 and 4, estimates of mean load based on daily 

mean water discharge for dissolved solids and totalrecoverable copper were less than the 90-percent confidence interval.

At all sites, estimates of mean load based on 

daily mean water discharge for chemical oxygen 

demand and suspended solids were larger than mean 

loads estimated by the mean load equations. At all 

sites, estimates of mean load based on daily mean water 

discharge for dissolved solids, total nitrogen, and totalrecoverable copper were smaller than mean loads estimated by the equations. Estimates of mean load for 

total ammonia plus organic nitrogen as nitrogen, total 

phosphorus, dissolved phosphorus, total-recoverable 

lead, and total-recoverable zinc based on daily mean 

water discharge when compared to mean loads estimated by the mean load equations had no consistent 

direction of bias. Generally, the mean load of six 

storms was within the 90-percent confidence interval of 

the mean load equations. The mean load of the six 

storms for each site exceeded the upper 90-percent confidence interval for chemical oxygen demand and suspended solids at site 1. The mean load of the six storms 

was less than the lower 90-percent confidence interval 

for dissolved solids at sites 2, 3,4, and 5; for totalrecoverable copper at sites 3, 4, and 5; and for totalrecoverable lead at site 3.

The mean load of the six storms at each site compared well with the estimates derived using the mean 

load equations. However, these mean loads represent 

only 6 storms, whereas the equations were developed 

using between 200 and 1,000 storms that represent 

drainage basins having a wider range of drainage-basin 

area and percent impervious area. Therefore, the mean 

load equations might provide a better estimate of mean 

loads, and hence annual and seasonal load, for ungaged 

drainage basins in Colorado Springs.

REFERENCES CITED

Chow, Ven Te, 1964, Handbook of applied hydrology; a 

compendium of water-resources technology: New 

York, McGraw-Hill, variously paged.

Driver, N.E., and Tasker, G.D., 1990, Techniques for estimation of storm-runoff loads, volumes, and selected constituent concentrations in urban watersheds in the 

United States: U.S. Geological Survey Water-Supply 

Paper 2363,44 p.

Duan, Naihua, 1983, Smearing estimate A nonparametric 

retransformation method: Journal of the American Statistical Association, v. 78, no. 383, p. 605-610.

Ellis, S.R., Doerfer, J.T., Mustard, M.H., Blakely, S.R., and 

Gibbs, J.W., 1984, Analysis of urban storm-runoff data 

and the effects on the South Plane River, Denver metropolitan area, Colorado: U.S. Geological Survey 

Water-Resources Investigations Report 84-4159, 66 p.

Hansen, W.R., Chronic, John, and Matelock, John, 1978, 

Climatography of the Front Range urban corridor and 

vicinity, Colorado (reprint 1979): U.S. Geological Survey Professional Paper 1019,59 p. (Reprinted in 1979)

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

water resources: New York, Elsevier, 522 p.

Hoos, A.B., 1991, Storm-runoff quality and its relation to 

land use in the Nashville metropolitan area, Tennessee, 

in Jennings, M.E., ed., Symposium proceedings on 

urban hydrology: Bethesda, Md., American Water 

Resources Association, Technical Publication Series, 

TPS-91-4, p. 33.

Hoos, A.B., and Sisolak, J.K., 1993, Procedures for adjusting regional-regression models of urban-runoff quality 

using local data: U.S. Geological Survey Open-File 

Report 93-39, 39 p.

Iman, R.L., and Conover, W.J., 1983, A modern approach to 

statistics: New York, John Wiley, 497 p.

Kilpatrick, F.A., Kaehrle, W.R., Hardee, Jack, Cordes, E.H., 

and Landers, M.N., 1985, Development and testing of 

highway storm-sewer flow measurement and recording 

system: U.S. Geological Survey Water-Resources 

Investigations Report 85-4111,98 p.

Statistical Analysis System Institute, Inc., 1990, SAS/STAT 

user's guide Statistics (Version 6,4th ed.): Gary, 

N.C., 

SAS Institute, Inc., 1661 p.

U.S. Environmental Protection Agency, 1990, National pollutant discharge elimination system permit, permit 

application regulations for storm water discharges; final 

rule: Federal Register, v. 55, no. 222, Code of Federal 

Regulations, title 40, v. 55, no. 222, parts 122,123,124, 

p. 47990-48091.

U.S. Geological Survey, 1970, The national atlas of the 

United States of America, 335 p.

von Guerard, Paul, 1989, Suspended sediment and sedimentsource areas in the Fountain Creek drainage basin 

upstream from Widefield, southeastern Colorado: 

U.S. Geological Survey Water-Resources Investigations Report 88-4136, 36 p.

REFERENCES CITED 35

37
SUPPLEMENTAL DATA

SUPPLEMENTAL DATA 37
Table 16. Precipitation and runoff characteristics for samples collected at storm-runoff sites in Colorado Springs

[--, not available]

Date

Total 

precipitation 

(Inches)

Runoff 

(cubic feet)

Duration of 

runoff 

(minutes)

Peak flow Period that has less than 

(cubic feet 0.10 Inch of precipitation 

per second) (days)

Duration of 

precipitation 

(minutes)

384918104454201 - Sixteenth Hole, Valley-Hi Golf Course (Site 1)

06-03-92

06-23-92

06-26-92

07-02-92

'07-25-92

'08-10-92

'l 1-21-92

0.21

.07

.13

.08

.33

.20

.78

46,100

26,800

14,900

16,400

78,500

45,900

34,600

155

170

125

240

325

395

560

37.1

8.57

16.8

7.19

22.3

20.5

2.99

2.0

2.0

.5

3.0

9.0

7.0

8.0

110

101

50

127

240

-

385347104500601 - Chestnnt Street at Douglas Creek (Site 2)

'05-31-92

06-05-92

'06-19-92

06-27-92

07-29-92

08-03-92

'11-21-92

.22

.15

.29

.10

.23

.08

.25

20,500

11,400

16,400

8,330

23,200

7,920

10,200

545

115

395

70

195

115

620

6.06

12.1

15.2

8.11

20.5

4.92

0.87

3.0

5.0

14.0

.5

5.0

5.0

8.0

100

15

118

25

10

39

-

385240104493601 - Beacon Street at Bnchanan Street (Site 3)

'06-05-92

'06-19-92

06-23-92

06-27-92

08-02-92

08-03-92

'11-11-92

.12

.29

.14

.08

.06

.14

.24

3,470

15,800

5,770

3,960

3,450

7,030

3,620

125

355

210

205

165

265

515

2.78

4.92

1.24

2.59

2.14

3.72

0.50

5.0

8.0

4.0

2.0

5.0

1.0

10.0

15

115

120

~

15

13

-

385118104485801 - Wahsatch Street at Cross Lane (Site 4)

05-26-92

06-03-92

'06-12-92

06-26-92

'07-25-92

07-29-92

'l 1-21-92

.30

.25

.10

.32

.41

.19

.27

10,400

9,400

6,030

41,400

48,900

22,600

6,670

195

160

150

285

285

175

545

3.19

10.2

3.82

15.4

13.9

13.9

0.72

1.0

3.0

3.0

1.0

8.5

4.0

8.0

120

15

15

45

95

10

-

384935104501501 - Walmart at Eighth Street (Site 5)

06-10-92

06-26-92

'07-17-92

'08-03-92

08-04-92

08-05-92

'12-06-92

.10

.05

.15

.10

.05

.17

.15

6,890

1,560

5,990

2,990

1,440

6,400

345

115

60

205

70

70

105

210

8.58

2.87

9.59

5.35

1.92

5.09

0.10

1.0

3.0

9.0

6.0

0.8

1.1

15.0

10

35

7

20

35

35

-

Samples required for storm-water permit.

38 Water Quality of Storm Runoff and Comparison of Procedures for Estimating Storm-Runoff Loads, Volume, EventMean Concentrations, snd the Mean Load for a Storm for Selected Properties and Constituents for Colorado Springs, 

Southeastern Colorado, 1992
Table 17. Values for instantaneous water discharge, pH, specific conductance, water temperature, fecal coliform, fecal streptoc

and grease, and phenols for storm-runoff sites in Colorado Springs

[ft3/s, cubic feet per second; nS/cm, microsiemens per centimeter at 25 degrees Celsius, deg C, degrees Celsius; cols./100 rnL, colonies per 100 milliliters; K, 

Hg/L, micrograms per liter; <, less than; dashes indicate no data]

g o 

 o

m

m

z

2

a

to

Date

07-25-92 

07-25-92

07-25-92

08-10-92

08-10-92

08-10-92

08-24-92

11-21-92

11-21-92

11-21-92

05-31-92

05-31-92

05-31-92

06-19-92

06-19-92

11-21-92

11-21-92

11-21-92

11-21-92

11-21-92 

06-05-92

06-05-92 

06-19-92

06-19-92

06-19-92 

11-11-92

11-11-92

11-11-92

Time

1424 

1442

1553

0910

0955

1050

0825

0935

1311

1540

1330

1430

1535

1731

1830

0920

1050

1220

1345

1635 

1300

1310 

1740

1800

1835 

0805

1020

1245

Instantaneous 

water 

discharge

7.0 

20

2.2

6.2

.31

.18

.40

.40

2.55

.51

.43

1.71

3.10

15.2

.74

.04

.21

.61

.74

.07 

1.0

.50

3.1

4.3

.88 

.15

.43

.09

pH 

(standard 

units)

7.3 

8.7

7.5

6.7

7.5

7.8

-

7.2

8.1

7.7

7.3

6.7

7.8

6.5

7.4

-

7.9

8.3

8.3

8.0 

6.7

6.7 

6.3

7.2

7.2

7.9

7.9

Specific Tempconduct- erature, 

ance water 

(US/cm) (deg C)

Fecal 

coliform 

(cols/100 

mL)

Fecal streptococci 

(colsVIOOmL)

384918104454201 - Sixteenth Hole, Valley-Hi Golf Course (Site 1) 

19.0 

18.5

-

-

-

-

-

380

240

260

385347104500601

385

68

52

~

-

-

390

750

450

19.5

19.0

17.0

15.0

-

3.5

4.5

4.0

-

1,300

K223.000

60,000

1,900

K175

-

K75

-

K22.000

53,000

K103,000

9,100

2,980

-

1,070

Total 

residual 

chlorine 

(mg/L)

0 

0

0

0

0

0

-

0

0

0

- Chestnut Street at Douglas Creek (Site 2)

19.0

15.5

13.5

22.5

20.0

.5

2.0

2.0

2.0

840

K873

K1.150

21,000

23,000

K100

-

K67

-

9,300

K28.000

4,800

K12.000

K13.000

1,950

-

K1.400

-

290 3.5 K50 K1.070 

385240104493601 - Beacon Street at Buchanan Street (Site 3) 

92 20.5 480 27,000

92

135

76

71

-

20.5 

22.0

19.5

20.5 

5.0

4.0

8.0

1,375 

2,900

3,500

K2,100 

K20.000

K3 1,000

7,500 

5,600

K14.000

K15,000 

59,000

-

K36.600

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0
Table 17. Values for instantaneous water discharge, pH, specific conductance, water temperature, fecal coliform, fecal strepto

Water Qualitions, andtf

o <

V O

if StormRi /lean Load

!l

en Q)

 3 

0 Q.

3 °

£1

||

5 5

ll

3 Q. 

<p 5

0) <»

Q. O

J? m

H

» to

qii

llo j

 Q.

«g -*

CO -

ll

S

__ 

<

o I?

O_ 0)

3 o

Q. O

<o ~

tv> 5

Date Time

Instantaneous 

water 

discharge

pH 

(standard 

units)

Specific 

conductance 

(jiS/cm)

Temperature, 

water 

(deg C)

Fecal 

coliform 

(cols/IOO 

mL)

Fecal streptococci 

(cols/IOOmL)

Total 

residual 

chlorine 

(mg/L)

385118104485801 - Wahsatch Street at Cross Lane (Site 4)

06-12-92

06-12-92

07-25-92

07-25-92

07-25-92

08-16-92

11-21-92

11-21-92

11-21-92

11-21-92

11-21-92

1507

1540

1410

1430

1610

2050

1005

1230

1415

1700

1730

3.4

1.3

5.6

10.7

1.3

3.6

.01

.12

.68

.09

.05

7.6

6.7

7.1

7.0

7.4

~

-

7.7

6.9

7.4

7.4

68

91

84

-

-

-

-

23.0

24.5

19.0

20.0

20.5

-

5.5

5.0

1.0

2.0

2.0

384935104501501-

07-17-92

07-17-92

07-17-92

08-03-92

08-03-92

08-03-92

08-16-92

12-06-92

12-06-93

12-06-92

0255

0325

0415

1719

1733

1750

2030

1120

1240

1400

4.7

.14

.08

4.72

.68

.06

-

.01

.04

.01

6.5

7.1

7.8

6.4

6.8

7.2

-

7.2

..

7.8

87

116

146

93

121

174

5850

..

6060

15.5

15.5

15.0

22.0

22.5

22.0

-

0.0

.0

4.0

5,400

Kl 1,000

3,070

K600

K131.000

--

4,900

-

43,000

KIOO.OOO

_

24,000

2,950

1,070

-

K17.000

-

0

0

0

0

-

0

0

0

0

0

Walmart at Eighth Street (Site 5)

~

.1

-

286

143

675

K7.000

K225

K275

~

..

--

31,000

33,000

32,000

12,200

K667

2,000

0

0

0

0

0

0

-

0

0

-
Table 18. Selected volatile-organic compounds for storm-runoff sites in Colorado Springs 

[All constituents in micrograms per liter; <, less than]

Date Time

Aero- Acrylo- Ben- " Bromo 

lein, nitrite, zene, " ' form, 

total total total water, tota| 

whole,

total

Carbon 

tetrachlorlde, 

total

Chlorobenzene, 

total

Chlorodl- Chloro- Chlorobromo- ethane, form, 

methane, total total 

total

384918104454201 - Sixteenth Hole, Valley-Hi Golf Course (Site 1)

07-25-92

07-25-92

07-25-92

07-25-92

08-10-92

08-10-92

08-10-92

'11-21-92

'11-21-92

'11-21-92

Date

07-25-92

07-25-92

07-25-92

07-25-92

08-10-92

08-10-92

08-10-92

'l 1-21-92

'11-21-92

'11-21-92

1424

1442

1500

1553

0910

0955

1050

0935

1311

1540

Methylchloride, 

total

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<20

<20

<20

<20

<20

<20

<20

<20

<20

<20

Cls-1,2- 

dichloroethene, 

water, 

total

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<20 <0.2 <0.2 <0.2

<20 <.2 <.2 <.2

<20 <.2 <.2 <.2

<20 <.2 <.2 <.2

<20 <.2 <.2 <.2

<20 <.2 <.2 <.2

<20 <.2 <.2 <.2

<20 <.2 <.2 <.2

<20 .4 <.2 <.2

<20 <.2 <.2 <.2

Dibromo- DlCls-1 ,3- chloro- bromodl- pro- methane, 

chloro- pene, water, 

pro- water, whole, 

pene, whole, total 

total total recovrecov- ereble

erable

<0.2 <1.0 <0.2

<.2 <1.0 <.2

<.2 <1.0 <.2

<.2 <1.0 <.2

<.2 <1.0 <.2

<.2 <1.0 <.2

<.2 <1.0 <.2

<.2 <1.0 <.2

<.2 <1.0 <.2

<.2 <1.0 <.2

<0.2

<.2

<.2

<.2

<.2

<2

<.2

<.2

<.2

<.2

Dlchlorobromomethene, 

total

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<0.2

<2

<.2

<.2

<.2

<2

<.2

<.2

<.2

<.2

Dl-chlorodl-fluoromethane, 

total

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<2

<0.2 <0.2 <0.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <2

<.2 <.2 <.2

<.2 <.2 <.2

IsoHmr_ propyl- =f <r- £

zene, .. water,

total tota!' Whole' 

recoverable

<0.2 <0.2 <0.2

<.2 <.2 <.2

<.2 <.2 <2

<.2 <.2 <.2

<.2 <.2 <2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

.3 <2 <.2

<.2 <.2 <.2

SUPPLEMENTAL DATA 41
Table 18. Selected volatile organic compounds for storm-runoff sites in Colorado Springs-Continued

Date

Methylbromide, 

total

Methylene 

chloride, 

total

N-butyl- **" P-lsoat = 

'

-sr Toluene, 

total

07-25-92 

07-25-92 

07-25-92

07-25-92

08-10-92 

08-10-92 

08-10-92 

'11-21-92 

'11-21-92 

'11-21-92

<0.2

384918104454201 - Sixteenth Hole, Valley-Hi Golf Course (Site l)-Continned

<0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 

<2

<0.2

<2 0.2

<2

<2 

<2

<2

.6 

.5

<2 

<2

<2 

<2

<2

2.2 

.7

Date

07-25-92

07-25-92

07-25-92

07-25-92

08-10-92

08-10-92

08-10-92

'11-21-92

'11-21-92

'11-21-92

CIs- Trans1,3-dl- 1,3dlchloro- chtoropro- propene, pene, 

total total

<0.2 <0.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

Trl- Tr|-

chloro- J*- V'7'- 

.thui fluoro- chloenf meth- ride«

total f"6; total total

<0.2 <0.2 <0.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <-2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

Tertbutylbenzene, 

water, 

whole, 

recoverable,

total

<0.2

<2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<2

Xylene, 

water, 

whole, 

recoverable, 

total

<0.2

<.2

0.2

<.2

<.2

<.2

<.2

<.2

2.3

.8

1,1-dlchloropropene, 

water, 

whole, 

total

<0.2

<2

<2

<2

<2

<.2

<2

<.2

<2

<2

1,1* "-* V:1 -

^hi«r«_ chloro- tn- eth^t ethy- chlor°-

e'ha"f' ene. ethane, 

t0tal total total

<0.2 <0.2 <0.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<2 <.2 <.2

<.2 <.2 <.2

42 Water Quality of Storm Runoff and Comparison of Procedures for Estimating Storm-Runoff Loads, Volume, EventMean Concentrations, end the Mean Load for a Storm for Selected Propertlea and Constituents for Colorado Springs, 

Southeastern Colorado, 1992
Table 18. Selected volatile organic compounds for storm-runoff sites in Colorado Springs-Continued

Date

1,1,1,2-

tetrachloroethane, 

water, 

whole,

total

1,1,2-trlchloroethane, 

total

1,1,2,2- 

tetrachloroethane, 

total

384918104454201

07-25-92

07-25-92

07-25-92

07-25-92

08-10-92

08-10-92

08-10-92

'11-21-92

'11-21-92

'l 1-21-92

Date

07-25-92

07-25-92

07-25-92

07-25-92

08-10-92

08-10-92

08-10-92

'11-21-92

'11-21-92

'11-21-92

<0.2

<.2

<2

<.2

<2

<.2

<2

<.2

<.2

<.2

1,2,3-trlchloropropane, 

water,

whole,

total

<0.2

<.2

<.2

<.2

<2

<2

<.2

<.2

<.2

<.2

<0.2

<2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

1,2,4-trlchlorobenzene,

total

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

1,2,4-trlmethyibenzene, 

water, 

whole,

recoverable,

total

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

.6

.3

1,2-dibromoethane, 

water, 

whole, 

total

0-chiorobenzene, 

1,2-dlchlorobenzene, 

total

1,2-dlchioroethane, 

total

. ., 0-chloro- ... 1,2-dl- ,-,. _ 1,2-transchloro- I0iuene' dl-chloropropane, > ethylene,

totel S' total

1,2,3-

trichlorobenzene, 

water, 

whole 

recoverable

total

- Sixteenth Hole, Valley-Hi Golf Course (Site l)-Continned

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

1,3-dlchlorobenzene,

total

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<2

<2

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

1,3-dlchloropropane, 

water,

whole,

total

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

1,3,5-trlmethyibenzene, 

water,

recoverable

<0.2

<.2

<.2

<.2

<.2

<.2

<2

<.2

.2

<.2

<0.2 <0.2 <0.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

Para- 2- 

chloro- 1 ,4-dl- chlorotoluene, chloro- ethylwater, benzene, vinylwhole, total ether,

total total

<0.2 <0.2 <1.0

<.2 <.2 <1.0

<.2 <.2 <1.0

<.2 <.2 <1.0

<.2 <.2 <1.0

<.2 <.2 <1.0

<.2 <.2 <1.0

<.2 <.2 <1.0

<.2 <.2 <1.0

<.2 <.2 <1.0

<0.2

<2

<.2

<.2

<.2

<2

<.2

<.2

<.2

<2

2,2-dichloropropane, 

water,

whole,

total

<0.2

<.2

<.2

<2

<.2

<.2

<2

<.2

<.2

<2

SUPPLEMENTAL DATA 43
Table 18. Selected volatile organic compounds for storm-runoff sites in Colorado Springs-Continued

Date

Bromo- Carbo - ChloroAcro- Acrylo- benzene, Bromo- . * Chloro- di- Chloro- ChloroTime lein, nitrite, Benzene. weter, form, uf ,J benzene, bromo- ethane, form, 

total total whole, total cniorrae, tota| methene, total total 

total total total

385347104500601 - Chestnut Street at Douglas Creek (Site 2)

05-31-92

05-31-92

06-19-92

06-19-92

'11-21-92

'11-21-92

'11-21-92

Date

05-31-92

05-31-92

06-19-92

06-19-92

'11-21-92

'11-21-92

'11-21-92

Date

05-31-92

05-31-92

06-19-92

06-19-92

'11-21-92

'11-21-92

'11-21-92

1330 <20 <20 <0.2

1535 <20 <20 <.2

1731 <20 <20 <.2

1830 <20 <20 <.2

1050 <20 <20 <.2

1345 <20 <20 <.2

1635 <20 <20 <.2

Cls-1,2- 

Hi. Cls.-1.3- 

Methyl- a^_ dichlorlde, chloro- «" "S? PT*--

total total

<0.2 <0.2 <0.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

N-butylMethyl- Methy|- benzene» 

' ene water, 

bromide, cn|Orjde whole, 

total ... total recoverable

<0.2 <0.2 <0.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

Dibromochloropropane, 

water, 

whole, 

totalrecovereble

<1.0

<1.0

<1.0

<1.0

<1.0

<1.0

<1.0

N-propyl 

benzene, 

water, 

whole, 

recoverable

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

Dlbromomethane, 

water, 

whole, 

recoverable

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

Nephthalene, 

total

<0.2

<.2

<.2

<.2

.4

.2

.2

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

Dlchlorobromomethane, 

total

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

P-lsopropyltoluene, 

water, 

whole,

recoverable

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<0.2 <0.2 <0.2 <0.2

<.2 <.2 <.2 <.2

<.2 <.2 <.2 <2

<.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2

Isochloro- HeXa" Pr°Py'- 

.. Ethyl- chloro- benzene,

 ,.' benzene, buta- water, tiuoro- tota| d wh

methane, ... 

total total recoyerable

<0.2 <0.2 <0.2 <0.2

<.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2

Sec-

. buty'- Tetrenzene, Styrene, chloro- Toluene, 

wa , ' total ethylene, total 

whole' total recoverable

<0.2 <0.2 <0.2 <0.2

<.2 <.2 <.2 <.2

<.2 <.2 <.2 .4

<.2 <.2 <.2 <.2

<.2 <.2 <.2 .2

<.2 <.2 <.2 <.2

<2 <.2 <.2 .2

44 Water Quality of Storm Runoff and Comparison of Procedures for Estimating Storm-Runoff Loads, Volume, EventMean Concentrations, and the Mean Load for a Storm for Selected Properties and Constituents for Colorado Springs, 

Southeastern Colorado, 1992
Table 18. Selected volatile organic compounds for storm-runoff sites in Colorado Springs-Continued

Date

05-31-92

05-31-92

06-19-92

06-19-92

'11-21-92

'11-21-92

'11-21-92

Dete

05-31-92

05-31-92

06-19-92

06-19-92

'11-21-92

'11-21-92

'11-21-92

Date

05-31-92

05-31-92

06-19-92

06-19-92

'11-21-92

'11-21-92

'11-21-92

Cis-1,3- 

dichloropropene, 

total

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

1,1,1,2

tetrachloroethane, 

weter, 

whole,

totel

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

1,2,3-trlchloropropane, 

water, 

whole,

total

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

Tra"!" Trl- ' . , butyl- xy|8n8' chloro- 1,1-dl- 1,1-di- 1,1,1- 1,3-di- . chloro- Vinyl- . water, /. ., . 

.. chloro- .. _ _,_ benzene, . . pro- chloro- chloro- tri- chloro- .. . fluoro- chlo- . whole, ... ... . . ethyl- water, ' pene, ethyl- ethyl- chloroK. fTi ane" Si »"<>"» *co - «-* "; «; »« .

total total total rec°v- arable wfh«le' total total total erable total

385347104500601 - Chestnut Street at Donglas Creek (Site 2)-Continned

<0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 .4 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <2 <.2

<.2 <.2 <.2 <.2 <.2 .7 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 .3 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 .2 <.2 <.2 <.2 <.2

12-di- 1,2,3-tri1,1,2-trl- V;2'2" b''°mo^ 1,2-dl- 1,2-dl- 1,2-dl- °-<;hloro- 1>2-trans . chk>rochloro- I"** ethane, chloro- chloro- chloro- tolufne' dl-chloro- benz,ene' 

... chloro- . ' . .. water, .. . water, ethane, water, benzene, ethane, propane, ' ethylene,

toU, ** ' whole, tota, tote, toU, "JJ- to.a, Jj£

total erable

<0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

1 '2'J:*ri- 1.3-dl- 1 '3'5;tr|1- Pera- 2- 2,2-di1,2,4-trl- y" 1,3-dl- chloro- y chloro- 1,4-dl- chloro- chlorochloro- water9' chlor°- propane, \^" toluene, chloro- ethyl- propane, 

benzene, whoie' benzene, water, a er' water, benzene, vinyl- water, 

total ' total whole, ' whole, total ether, whole,

erable" total ^ total total total

<0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <1.0 <0.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <1.0 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <1.0 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <1.0 <.2

<.2 .4 <.2 <.2 <.2 <.2 <.2 <1.0 <.2

<.2 .2 <.2 <.2 <.2 <.2 <.2 <1.0 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <1.0 <.2

SUPPLEMENTAL DATA 45
Table 18. Selected volatile organic compounds for storm-runoff sites in Colorado Springs-Continued

Date Time

Af*|*U

A MUl V

Aero- .

leln, total n'tr"

total

Benzene,

*' total

Bromobenzene, Bromowater,

whole,

total

form,

total

Carbontetrachlorlde,

total

Chlorobenzene,

total

Chlorodlbromomethane,

total

Chloroethane,

total

Chloroform,

total

385240104493601 - Beacon Street at Buchanan Street (Site 3)

06-05-92

06-05-92

06-19-92

06-19-92

06-19-92

'll-H-92

'll-H-92

'll-H-92

Date

06-05-92

06-05-92

06-19-92

06-19-92

06-19-92

'11-11-92

l U-ll-92

hl-11-92

Date

06-05-92

06-05-92

06-19-92

06-19-92

06-19-92

'll-ll^

hl-11-92

hl-11-92

1300

1310

1740

1800

1835

0805

1020

1245

Methylchloride, 

total

<0.2

<2

<.2

<2

<2

<2

<.2

<2

Methylbromide, 

total

<0.2

<2

<2

<.2

<2

<2

<.2

<2

<20 <20

<20 <20

<20 <20

<20 <20

<20 <20

<20 <20

<20 <20

<20 <20

Cls-1,2- 

dlchloroethene, 

water,

total

<0.2

<.2

<.2

<.2

<2

<.2

<2

<.2

Methylenechlorlde, 

total

<0.2

<2

<2

<.2

<2

<2

<2

<2

<0.2

<.2

<.2

<2

<2

<.2

<.2

<2

Cls-1,3- 

dlchloropropene,

total

<0.2

<.2

<.2

<.2

<.2

<2

<.2

<2

N-butylbenzene, 

water, 

whole, 

recov-

<0.2

<2

<.2

<2

<2

<.2

<.2

<2

<0.2

<.2

<2

<.2

<.2

<2

<.2

<.2

Dlbromochloropropane, 

water, 

whole,

totalrecoverable

<1.0

<1.0

<1.0

<1.0

<1.0

<1.0

<1.0

<1.0

Npropylbenzene, 

water, 

whole,

recoverable

<0.2

<2

<2

<2

<2

<2

<.2

<.2

<0.2

<2

<2

<.2

<.2

<.2

<.2

<.2

Dlbromomethane, 

water, 

whole,

recoverable

<0.2

<.2

<.2

<.2

<2

<.2

<2

<.2

Naphthalene, 

total

1.0

1.1

<2

.3

.4

.6

<2

.3

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

Dlchlorobromomethane,

total

<0.2

<.2

<.2

<.2

<2

<.2

<.2

.2

P-laopropyltoluene, 

water, 

whole,

recoverable

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

Dichlorodlfluoromethtotal

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

Secbutylbenzene, 

water, 

whole,

recoverable

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<0.2

<2

<.2

<.2

<.2

<.2

<.2

<2

Ethylbenzene, 

total

<0.2

<.2

<2

<2

<.2

<2

<2

<.2

Styrene, 

total

<0.2

<2

<2

<.2

<2

<2

<.2

<2

<0.2

<.2

<.2

<.2

<2

<2

<2

<2

Hexachlorobutadlene, 

total

<0.2

<2

<2

<.2

<2

<.2

<2

<2

Tetrachloroethylene, 

total

<0.2

<2

<2

<2

<.2

<.2

<.2

<.2

<0.2

<2

<.2

<.2

<.2

<2

<2

<2

Isopropylbenzene, 

water, 

whole

recoverable

<0.2

<.2

<.2

<2

<.2

<.2

<.2

<.2

Toluene, 

total

<0.2

<.2

<.2

<.2

<.2

.2

<.2

<.2

46 Water Quality of Storm Runoff and Comparison of Procedures for Estimating Storm-Runoff Loads, Volume, EventMean Concentrations, and the Mean Load for a Storm for Selected Propertlea and Conatltuents for Colorado Springs, 

Southeastern Colorado, 1992
Table 18. Selected volatile organic compounds for storm-runoff sites in Colorado Springs-Continued

Date

Cls-1,3- 

dichioropropane, 

total

Trans1,3-dichioropropene, 

total

Tert- ..

Tri Tri" bUtVl' Xy|ene, Ch|^l n^j,

chioro- chlor°- Vi7'- ben" watef' pro- 1 '1 -* chio^ 

eth I- fiuor°- chl°- zene, whole, H ^ chioro- eth 1- 

meth- ride, water, total, ' ethane,

lota! ane> t0tai Wh0ie' reCOV' whole' t0tal Intel

totai total recov- erabie wh^f' totai 

erabie

1,1,1- 

trltotal

385240104493601 - Beacon Street at Bnchanan Street (Site 3)-Continned

06-05-92

06-05-92

06-19-92

06-19-92

06-19-92

'11-11-92

'll-H-92

'll-H-92

Date

06-05-92

06-05-92

06-19-92

06-19-92

06-19-92

'11-11-92

'll-H-92

'11-11-92

Date

06-05-92

06-05-92

06-19-92

06-19-92

06-19-92

'll-H-92

'11-11-92

'11-11-92

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

1,1,1,2-

tetrachloroethane, 

water, 

whole, 

total

<0.2

<2

<.2

<.2

<.2

<.2

<.2

<.2

1,2,3-trichioropropane, 

water, 

whole, 

total

<0.2

<.2

<2

<.2

<.2

<2

<.2

<.2

<0.2

<.2

<2

<.2

<.2

<.2

<.2

<.2

1,1,2- 

tetrachloroethane, 

total

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

1,2,4-trichlorobenzene, 

total

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 .3 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 .5 <.2 <.2 <.2

1 ,2 di- OVf2'2 bromo- 1,2di- 1,2di- 1^dl- chioro- 1 '2" 

r|lra" ethane, chioro- chioro- chioro- toluene, 'ra"8-01' 

fihflnt water' benzene, ethane, propane, water, _«:'?.r^l 

etfhan1e> whole, total total totai whole, ethty'ene' 

totai totai total total

<0.2 <0.2 <30.2 <0.2 <0.2 <0.2 <0.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2

1,2,4-tri- 1,3,5-tri- 

^y'- 1.MI- chioro^ m*W Jfre- 1.4H«- h,2

*- "bir pPern°- -, £t -7- XT 

~. zTn:, SE 7f' re", Vi"Vl- ±i

^ . e: - -«* total 

rj;.- 

. . 

rr - ts

erabie erabie

<0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <1.0

<.2 <.2 <.2 <.2 <.2 <.2 <1.0

<.2 <.2 <.2 <.2 <.2 <.2 <1.0

<.2 <.2 <.2 <.2 <.2 <.2 <1.0

<.2 <.2 <.2 <.2 <.2 <.2 <1.0

.2 <.2 <.2 <.2 <.2 <.2 <1.0

<.2 <.2 <.2 <.2 <.2 <.2 <1.0

<.2 <.2 <.2 .2 <.2 <.2 <1.0

<0.2

<.2

<.2

<.2

<.2

<2

<.2

<.2

1,2,3-trlchiorobenzene, 

water, 

whole, 

recoverable

<0.2

<.2

<.2

<2

<.2

<.2

<.2

<.2

2,2-dichioropropane, 

weter, 

whole, 

total

<0.2

<2

<.2

<2

<.2

<.2

<2

<.2

SUPPLEMENTAL DATA 47
Table 18. Selected volatile organic compounds for storm-runoff sites in Colorado Springs-Continued

Date Time

Bromo- _ . Chloro- 

. caroon- _ .

Aero- Acrylo- Ben- D Bromo- tetra- r°r°~ h Chloro- Chloroleln, nltrlle, zene, " ' form, chlo- " ?J°~ ethane, form, 

total total total ^^ total ride, "^' ""J1" total total

Wtotal' total ° tS

385118104485801 - Wahsatch Street at Cross Lane (Site 4)

06-12-92

06-12-92

07-25-92

07-25-92

07-25-92

'11-21-92

'11-21-92

'11-21-92

Date

06-12-92

06-12-92

07-25-92

07-25-92

07-25-92

'11-21-92

'11-21-92

'11-21-92

Dste

06-12-92

06-12-92

07-25-92

07-25-92

07-25-92

'11-21-92

'l 1-21-92

'11-21-92

1507

1540

1410

1430

1610

1230

1415

1730

Methylchloride, 

total

<0.2

<2

<.2

<2

<2

<2

<.2

<.2

Methylbromide, 

total

<0.2

<.2

<.2

<2

<2

<2

<.2

<2

<20

<20

<20

<20

<20

<20

<20

<20

Cis-1,2- 

dichloroethene, 

water, 

total

<0.2

<.2

<2

<.2

<.2

<2

<2

<2

Methylenechlorlde, 

total

<0.2

<2

<.2

<2

<2

<2

<2

<2

<20 <0.2 <0.2

<20

<20

<20

<20

<20

<20

<20

Cls-1,3 

dlchloropropane, 

total

<0.2

<2

<2

<2

<2

<2

<2

<2

N-butylbenzene, 

water, 

whole, 

recoverable

<0.2

<2

<2

<2

<.2

<2

<2

<.2

<.2 <2

<2 <2

<.2 <2

<.2 <2

<.2 <.2

.3 <2

<.2 <.2

Dlbromochloropropene, 

water, 

whole, 

total

recoverable

<1.0

<1.0

<1.0

<1.0

<1.0

<1.0

<1.0

<1.0

Npropylbenzene, 

water, 

whole,

recoverable

<0.2

<.2

<2

<2

<.2

<.2

<.2

<.2

<0.2

<2

<2

<.2

<.2

<.2

<.2

<.2

Dibromom ethane, 

water, 

whole, 

recoverable

<0.2

<2

<2

<.2

<2

<.2

<.2

<2

Naphthalene, 

total

0.3

<2

<2

<2

<2

.2

.3

.4

<0.2

<2

<.2

<.2

<.2

<.2

<2

<.2

Dlchlorobromomethane, 

total

<0.2

<2

<.2

<2

<2

<.2

<.2

<.2

P-laopropyltoluene, 

water, 

whole, 

recoverable

0.2

<2

<.2

<.2

<.2

<.2

<2

<2

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

Dlchlorodifluoromethane,

total

<0.2

<.2

<2

<.2

<2

<2

<.2

<.2

butylbenzene, 

water, 

whole,

recoverable

<0.2

<2

<.2

<2

<2

<2

<.2

<.2

<0.2

<.2

<.2

<2

<.2

<.2

<.2

<.2

Ethylbenzene, 

total

0.2

<.2

<.2

<2

<.2

<2

<.2

<.2

Styrene, 

total

<0.2

<2

<2

<2

<2

<2

<2

<2

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

Hexachlorobutadiene, 

total

<0.2

<2

<.2

<.2

<2

<2

<.2

<.2

Tetrachloroethylene, 

total

<0.2

<2

<.2

<.2

<2

<.2

<2

<.2

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

Isopropylbenzene, 

water, 

whole, 

recoversble

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

Toluene, 

total

0.5

.6

<.2

.3

<.2

1.2

1.1

.3

48 Water Quality of Storm Runoff and Comparison of Procedures for Estimating Storm-Runoff Loads, Volume, EventMean Concentrations, and the Mean Load for a Storm for Selected Propertiea and Constituents for Colorado Springs, 

Southeastern Colorado, 1992
Table 18. Selected volatile organic compounds for storm-runoff sites in Colorado Springs-Continued

Date

06-12-92

06-12-92

07-25-92

07-25-92

07-25-92

'11-21-92

'11-21-92

'11-21-92

1119. ) » ',^

tetrachloroethane, 

water, 

whole,

total

06-12-92

06-12-92

07-25-92

07-25-92

07-25-92

'11-21-92

'11-21-92

'11-21-92

Date

06-12-92

06-12-92

07-25-92

07-25-92

07-25-92

'11-21-92

'11-21-92

'11-21-92

Cis-1,3-

dichloropropene,

total

<0.2

<2

<2

<.2

<.2

<.2

<.2

<.2

1,1,2-trlchloroethane, 

total

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

1,2,3-trichloropropane, 

weter, 

whole,

total

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

Trans1,3-dichloropropene,

total

<0.2

<2

<.2

<.2

<.2

<.2

<.2

<.2

1,1,2,2- 

tetrachloroethane, 

total

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

1,2,4-trlchlorobenzene, 

total

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<2

Tert- 1 1 ..

T i Tri" butyi' Xylene, .-I. ~ ^ ^ .,,

chioro- Vinyl- ben- water, cmoro" ^^i. ^J-01'

tifT fiuor°- chi°- "no- whole- « chior°- fhi 

^JjJ1 " meth- ride, water, total JJ|J ethane- ene

tota| f«1!'i total ~^' ^h£ who|e- total total

total recov- erable . .

385118104485801 - Wahsatch Street at Cross Lane (Site 4)-Continued

<0.2 <0.2 <0.2 <0.2 1.5 <0.2 <0.2 <0.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 .3 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 .7 <2 <.2 <.2

<.2 <.2 <.2 <2 .3 <2 <.2 <2

1,2-di- 0- 1,2- 

bromo- ', '7 1,2-di- 1,2-di- chioro- trans-diethane, ^f cj'e°nrf chioro- chioro- toluene, chloroweter, * ethene, propane, weter, ethylwhole, ^e"e.' . ..' total total whole, ene, 

, , . total total . , . , , , totel total total

<0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <2 <.2 <.2 <.2

<.2 <-2 <2 <.2 <2 <.2 <.2

1,2,4-tri- 1,3,5-trimethyi- 1 . . 1,3-di- methyl- Para- 1 ^. 2- 

ben- ', chioro- ben- chioro- ', chiorozene, CJ"or°- propane, zene, toluene, "^ ethyiWater> 7PHP Water' Water' Water- zVnJ Viny'- 

whole, * ' whole, whole, whole, * ' ether,

recov- Ioa totel recov- total Iolal total

erable ereble

0.9 <0.2 <0.2 0.3 <0.2 <0.2 <1.0

<.2 <.2 <.2 <.2 <.2 <.2 <1.0

<.2 <.2 <.2 <.2 <.2 <.2 <1.0

<.2 <.2 <.2 <.2 <.2 <.2 <1.0

<.2 <.2 <.2 <.2 <.2 <.2 <1.0

<.2 <.2 <.2 <.2 <.2 <.2 <1.0

.3 <.2 <.2 <.2 <.2 <.2 <1.0

.2 <.2 <.2 <.2 <2 <.2 <1.0

1,1,1-

trichloroethane,

total

<0.2

<2

<2

<2

<2

<.2

<2

<2

1,2,3-trichlorobenzene, 

water, 

whole, 

recoverable

<0.2

<.2

<.2

<.2

<.2

<2

<2

<2

2-2-dichloropropane, 

water, 

whole, 

total

<0.2

<.2

<.2

<2

<.2

<.2

<.2

<2

SUPPLEMENTAL DATA 49
Table 18. Selected volatile organic compounds for storm-runoff sites in Colorado Springs-Continued

Date Time

Bromo- ^ur^^nn. Chloro- 

. , D ben- D maroon- Ch|oro_ d|. 

Aero- Acryio- Ben- Bromo- tetra- b-n_ bromo_ 

lein, nitriie, zene, form, chlo- .. 

total total total . ' total ride, ,'

tote?' total to taotei

Chioro- Chloroethane, form, 

total total

384935104501501 - Walmart at Eighth Street (Site 5)

07-17-92

07-17-92

07-17-92

08-03-92

08-03-92

08-03-92

'12-06-92

'12-06-92

'12-06-92

Date

07-17-92

07-17-92

07-17-92

08-03-92

08-03-92

08-03-92

'12-06-92

'12-06-92

'12-06-92

Date

07-17-92

07-17-92

07-17-92

08-03-92

08-03-92

08-03-92

'12-06-92

'12-06-92

'12-06-92

0255

0325

0415

1719

1733

1750

1120

1240

1400

Methylchloride, 

total

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<2

<.2

Methylbromide, 

total

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<20 <20 <0.2 <0.2

<20 <20 <.2 <.2

<20 <20 <.2 <.2

<20 <20 <.2 <.2

<20 <20 <.2 <.2

<20 <20 <.2 <.2

<20 <20 <.2 <.2

<20 <20 .3 <.2

<20 <20 <.2 <.2

Di-bromoCis-1,2- Cls-1,3- chlorodi- di- propane,

chioro- chioro- water, 

ethene, pro- whole, 

water, pene, total 

total total recoverable

0.2 <0.2 <1.0

<.2 <.2 <1.0

<.2 <.2 <1.0

<.2 <.2 <1.0

<.2 <.2 <1.0

<.2 <.2 <1.0

<.2 <.2 <1.0

<.2 <.2 <1.0

<.2 <.2 <1.0

-r"- ,4*

Methyl- "" benene, JJJJ zene, 

chloride, ' water, **" ££ «*» 

 =

<0.2 <0.2 <0.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 .4 .3

<2 <.2 <.2

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

Dibromomethane, 

water, 

whole, 

recoverable

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

Naphthalene, 

total

0.2

<.2

<.2

.2

.2

<.2

4.7

1.6

1.1

<0.2 <0.2 <0.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

Di- Di' 

chioro- CM^°- EthyibromK°- fluoro- ben'

meth- meth- ze"e; 

ane, total

... ciriBf total total

<0.2 <0.2 <0.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 .3

55- 5

 rr -T *rr

v*ol» «?"« lotel »««: «'">"> 

 SE

<0.2 <0.2 <0.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <2

<2 <.2 <.2

<.2 <.2 <2

<2 <.2 <.2

<0.2 2.1

<.2 .9

<.2 2.0 

<2 <.2

<2 <.2

<.2 <.2

<.2 <.2

<.2 .7

<2 1.1

Iso-

 propylK?Xa" "enchioro- buta- ze"e'

r- ss: total 

recoverable

<0.2 <0.2

<.2 <.2

<.2 <.2

<2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

Tetrachloro- _ ,

ethyl- Touf"e' 

' total 

ene,

total

<0.2 0.2

<2 <.2

<.2 <.2

<.2 <.2

<.2 .3

<.2 <.2

<.2 .2

<.2 1.7

<.2 .2

50 Water Quality of Storm Runoff and Comparison of Procedures for Estimating Storm-Runoff Loads, Volume, EventMean Concentrations, and the Mean Load for a Storm for Selected Properties and Constituents for Colorado Springs, 

Southeastern Colorado, 1992
Table 18. Selected volatile organic compounds for storm-runoff sites in Colorado Springs-Continued

Date

Cis-1,3- 

dlchloropropene, 

total

Trsns- _ , Trlchloro chloro*

DGnG*

totdl

Tri- Xylene, '

butyl cnloro 1,2-cll chloro vinyl . water, 1,1 -dl _

fluoro- chlo- . whole, chloro- .. M&tu ijriA waier, *f**^t P®ri®, M«U__>K einyi- meth- ride, whole total water ethane, e 

ane. total ' recov- ' total ' 

recov- whole, total

erable total

1,1,1- 

tri384935104501501 - Walmart at Eighth Street (Site 5)-Continued

07-17-92

07-17-92

07-17-92

08-03-92

08-03-92

08-03-92

'12-06-92

'12-06-92

'12-06-92

Date

07-17-92

07-17-92

07-17-92

08-03-92

08-03-92

08-03-92

'12-06-92

'12-06-92

'12-06-92

Date

07-17-92

07-17-92

07-17-92

08-03-92

08-03-92

08-03-92

'12-06-92

'12-06-92

'12-06-92

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

1,1,1,2- 

tetrachloroethane, 

water, 

whole,

total

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

1,2,3-trlchloropropane, 

water, 

whole, 

total

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<0.2 <0.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

sr F

 s? ~

<0.2 <0.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

1,2,4-trlI-2- - Tn-'" chbT -- . WK !r>

total whole' 

recoverable

<0.2 <0.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 .3

<.2 2.8

<.2 .3

<0.2 <0.2 <0.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

<.2 <.2 <.2

1,2-dibromo- 1/? ethane, C^°r°-

5 =

<0.2 <0.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

1,3-di1,3-dl- chlorochloro- proben- pane, 

zene, water, 

total whole, 

total

<0.2 <0.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

<.2 <.2

<0.2 <0.2 <0.2 <0.2

<.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2

<2 <.2 <.2 <.2

.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2

.4 <.2 <.2 <2

4.4 <.2 <.2 <.2

.4 <.2 <.2 <.2

1 MI °- 1 '2' 1,2-dl- ^P"" chloro- trans-dlchloro- cnlor°- toluene, chloroethane, pro" water, ethyltotal "*;",' whole, ene, 

total total

<0.2 <0.2 <0.2 <0.2

<2 <.2 <.2 <.2

<.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2

1,3,5-trlmethyl- Para- 2- 

ben- chloro- ', chlorozene, toluene, c^°" ethylwater, water, " vinylwhole, whole, ^e"e' ether, 

recov- total total 

erable

<0.2 <0.2 <0.2 <1.0

<.2 <.2 <.2 <1.0

<.2 <.2 <.2 <1.0

<.2 <.2 <.2 <1.0

<2 <.2 <.2 <1.0

<.2 <.2 <.2 <1.0

<.2 <.2 <.2 <1.0

.9 <.2 <.2 <1.0

<.2 <.2 <-2 <1.0

<0.2

.7

.3

<.2

<.2

<.2

<.2

<2

<.2

1,2,3-trichlorobenzene, 

water, 

whole, 

recoverable

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

2,2-dichioropropane, 

water, 

whole, 

total

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

'Snowmelt-runnoff sample.

SUPPLEMENTAL DATA 51
Table 19. Chemical oxygen demand, 5-day biochemical oxygen demand, specific conductance, alkalinity, dissolved solids, 

suspended solids, major ions, nutrients, and total-recoverable metals for storm-runoff sites in Colorado Springs

[mg/L, milligrams per liter, nS/cm, microsiemens per centimeter at 25 degrees Celsius; jlg/L, micrograms per liter; lab, laboratory; dashes indicate no data; 

<, less than]

Date Time

Oxygen

demand, 

chemical, 

high 

level

(mg/L)

Oxygen

demand, 

biochemical, 

5-day

(mg/L)

Specific 

conductance 

(US/cm)

Alkalinity, 

lab 

(mg/L)

Solids, 

dissolved 

(mg/L)

Solids, 

suapended 

(mg/L)

Calcium, 

dissolved 

(mg/L)

Magnesium, 

dissolved 

(mg/L)

Potassium, 

dissolved 

(mg/L)

Sodium, 

dissolved 

(mg/L)

384918104454201 - Sixteenth Hole, Valley-Hi Golf Course (Site 1)

06-03-92

06-23-92

06-26-92

07-02-92

07-25-92

08-10-92

11-21-92

Date

06-03-92

06-23-92

06-26-92

07-02-92

07-25-92

08-10-92

11-21-92

Date

06-03-92

06-23-92

06-26-92

07-02-92

07-25-92

08-10-92

11-21-92

1410

2030

1453

1459

1423

0840

0930

Chloride, 

dissolved 

(mg/L)

-

1.0

.1

32

Cadmium, 

totalrecoverabla 

(H9/L)

<1

<1

<1

<1

<1

1

1

100

170

140

210

310

180

270

Sulfate, 

dissolved 

(mg/L)

-

-

21

2.2

27

Chromium, 

totalrecoverable 

(H9/L)

-

-

-

43

20

14

-

53

24

47

29

19

-

Nitrogan, 

ammonia, 

total, 

as 

nltrogan 

(mg/L)

0.98

.88

.28

.73

.28

.67

.41

Copper, 

totalrecoverable 

(H9/L)

10

9

15

13

12

12

17

114

147

107

--

105

133

256

Nitrogen, 

ammonia 

plus 

organic, 

total, 

as 

nitrogen

(mg/L)

1.7

2.2

1.6

2.4

1.5

2.1

.9

Lead, 

totalrecoverable 

(H9/L)

140

23

60

30

170

77

64

-

-

-

-

37

53

52

Nitrogen 

nitrite, 

total, 

aa 

nitrogen 

(mg/L)

0.03

.08

.03

.11

.02

.04

.07

Mercury, 

totalrecoverable 

(H9/L)

--

-

-

0.1

<.l

<.l

63

107

71

202

75

93

143

Nitrogen,

nitrate 

plua 

nitrite, 

total, 

as 

nitrogen 

(mg/L)

0.80

1.00

.52

.97

.40

.98

.46

Nickel, 

totalrecovarable 

(R9/1-)

--

-

-

5

11

9

321

121

372

136

242

524

274

Phosphorus, 

total, 

as 

phosphorus 

(mg/L)

0.14

.29

.33

.36

.29

.45

.12

Selenium, 

total 

(H9/U

-

-

-

<1

1

<2

-

-

9.9

13

14

Phosphorus, 

dissolved, 

as 

phosphorus 

(mg/L)

0.08

.15

.08

.28

.12

.14

.08

Silver, 

totalrecoverable 

(H9/L)

-

-

-

<1

<1

<1

-

-

2.4

2.9

3.6

Antimony, 

totalrecoverable

(ng/L)

~

-

-

-

<10

<10

<10

Thallium, 

total 

(H9/L)

-

--

--

-

<5

<5

<5

--

-

-

1.2

1.9

1.8

Arsenic, 

total

(ng/U

-

-

-

--

2

3

1

Zinc, 

totalrecoverable

(na/L)

180

140

190

190

180

300

250

-

-

--

5.2

5.4

25

Beryllium, 

totalrecoverable 

(HS/L)

-

-

-

<10

<10

<10

Carbon, 

organic, 

total 

(mg/L)

-

-

-

-

32

36

29

52 Water Quality of Storm Runoff and Comparison of Procedures for Estimating Storm-Runoff Loads, Volume, EventMean Concentrations, and the Mean Load for a Storm for Selected Properties and Constituents for Colorado Springs, 

Southeastern Colorado, 1992
Table 19. Chemical oxygen demand, 5-day biochemical oxygen demand, specific conductance, alkalinity, dissolved solids, 

suspended solids, major ions, nutrients, and total-recoverable metals for storm-runoff sites in Colorado Springs-Continued

Date Time

Oxygen

demand, 

chemical 

(high 

level)

(mg/L)

Oxygen

demand, 

biochemical, 

5 day

(mg/l)

Specific 

conductance 

(jiS/cm)

Alkalinity, 

lab 

(mg/L)

Solids, 

dissolved 

(mg/L)

Solids, 

suepended 

(mg/L)

Calcium, 

dissolved 

(mg/L)

Magnesium, 

dissolved 

(mg/L)

Potassium, 

dissolved 

(mg/L)

Sodium, 

dissolved 

(mg/L)

38534710450061 - Chestnut Street at Douglas Creek (Site 2)

05-31-92

06-05-92

06-19-92

06-27-92

07-29-92

08-03-92

11-21-92

Date

05-31-92

06-05-92

06-19-92

06-27-92

07-29-92

08-03-92

11-21-92

Date

05-31-92

06-05-92

06-19-92

06-27-92

07-29-92

08-03-92

11-21-92

1255

1230

1724

1705

1350

2050

0910

Chloride, 

dissolved 

(mg/L)

2.9

--

2.1

--

-

--

130

. Cadmium, 

totalrecoverable

1

2

2

<1

2

<1

1

230

420

280

310

150

100

190

Sulfate, 

dissolved 

(mg/L)

6.4

-

6.6

-

-

-

4.2

Chromium, 

totalracoverable

27

-

51

-

~

-

28

14

39

80

-

34

28

22

Nitrogen, 

ammonia, 

total, 

as 

nitrogen 

(mg/L)

0.43

.24

1.10

.49

.23

.56

.36

Copper, 

totalrecoverable

19

99

74

12

37

18

17

385

63

-

70

85

77

497

Nitrogen,

ammonia 

plus 

organic, 

total, 

as 

nitrogen

(mg/L)

1.0

2.4

2.3

1.3

.90

1.1

1.1

Lead, 

totalrecoverable 

(H9/L)

150

350

290

47

290

86

110

80

-

65

-

--

-

57

Nitrogen 

nitrite, 

total, 

as 

nitrogen 

(mg/L)

0.04

.03

.03

.06

.03

.04

.08

Mercury, 

totalrecoverable

<0.1

-

.1

-

<.l

68

63

121

55

34

60

256

Nitrogen, 

nitrate 

plus 

nitrite, 

total, 

as 

nitrogen 

(mg/L)

0.93

.61

1.10

1.10

.57

.87

.45

Nickal, 

totalrecoverable

8

-

22

-

-

8

396

1280

764

198

832

234

464

Phosphorus, 

total, 

as 

phosphorus 

(mg/L)

0.12

.72

.25

.20

.16

.09

.17

Selenium, 

total

<2

-

<2

-

-

<2

-

14

-

-

-

13

Phosphorus, 

dissolved, 

as 

phosphorus 

(mg/L)

-

0.12

.21

.07

.10

.08

.06

Silver, 

totalrecoverable 

(H9/L)

<1

-

<1

-

-

<'

-

1.1

-

-

-

0.95

Antimony, 

totalrecoverable 

(mg/L)

<10

<10

-

-

<10

Thallium, 

total

(jig/L)

<10

-

<10

-

<10

-

-

3.1

-

-

~

1.8

Arsenic, 

total 

(mg/L)

5

-

8

-

-

-

<1

Zinc, 

totalrecover 

able 

Gig/L)

700

1400

1400

290

550

570

230

~

3.3

-

-

-

77

Beryllium, 

total 

recoverable 

(mg/L)

<10

-

<10

-

~

<10

Carbon, 

organic, 

total 

(mg/L)

48

-

52

-

-

32

SUPPLEMENTAL DATA 53
Table 19. Chemical oxygen demand, 5-day biochemical oxygen demand, specific conductance, alkalinity, dissolved solids, 

suspended solids, major ions, nutrients, and total-recoverable metals for storm-runoff sites in Colorado Springs-Continued

Date Time

Oxygen

demand, 

chemical 

(high 

level)

(mgn.)

Oxygen

demand, 

biochemical, 

5 day

(mgn)

Specific 

conductance 

ftiS/cm)

385240104493601

06-05-92

06-19-92

06-23-92

06-27-92

08-02-92

08-03-92

11-11-92

Date

06-05-92

06-19-92

06-23-92

06-27-92

08-02-92

08-03-92

11-11-92

Date

06-05-92

06-19-92

06-23-92

06-27-92

08-02-92

08-03-92

11-11-92

1240

1735

2044

1712

1845

2055

0759

Chloride, 

dissolved 

(mg/L)

3.4

2.9

-

-

-

42

Cadmium, 

totalrecoverable

(H9/L)

2

2

<1

<1

2

2

1

170

300

200

160

270

120

260

Sulfate, 

dissolved 

(mgn.)

8.5

6.4

-

-

-

5.3

Chromium, 

totalrecoverable

(H9A-)

18

27

-

--

-

8

33

66

42

51

74

26

62

Nitrogen, 

ammonia, 

total, 

as 

nitrogen 

(mg/L)

0.76

1.30

.99

1.50

1.50

.48

.57

Copper, 

totalrecoverable

17

24

13

13

22

12

14

92

101

110

99

133

59

238

Nitrogen,

ammonia 

plus 

organic, 

total, 

as 

nitrogen

(mgn.)

2.9

3.5

2.7

3.7

4.0

1.6

1.8

Lead, 

totalrecoverable

(»gn-)

85

83

23

42

53

97

55

Alkalinity, 

lab 

(mgn.)

Solids, 

dissolved 

(mg/L)

Solids, 

suspended 

(mgn.)

Calcium, 

dissolved 

(mg/L)

Magnesium, 

dissolved 

(mgn.)

Potassium, 

dissolved 

(mg/L)

Sodium, 

dissolved 

(mg/L)

- Beacon Street at Bnchanan Street (Site 3)

40

44

-

-

-

41

Nitrogen 

nitrite, 

total, 

as 

nitrogen 

(mg/L)

.04

.04

.07

.06

.04

.03

.07

Mercury, 

totalrecoverable

<0.1

<.l

-

-

<.l

74

103

87

77

168

54

137

Nitrogen, 

nitrate 

plus 

nitrite, 

total, 

as 

nitrogen 

(mg/L)

0.84

1.00

1.10

1.00

1.40

.66

.68

Nickel, 

totalrecoverable

(H9"-)

12

17

-

6

330

340

101

162

220

272

116

Phosphorus, 

total, 

as 

phosphorus 

(mgn.)

0.30

.58

.27

.46

.44

.16

.33

Selenium, 

total

<2

<2

-

<2

13

13

-

-

-

-

13

Phosphorus, 

dissolved, 

as 

phosphorus 

(mgn.)

0.13

.51

.17

.20

.30

.10

.18

Silver, 

totalrecoverable

(US"-)

<1

1

-

<1

0.86

.91

-

-

-

1.0

Antimony, 

totalrecoverable 

(mg/L)

<20

<10

-

-

<10

Thallium, 

total

<5

<10

-

<10

2.2

3.1

-

~

-

2.6

Arsenic, 

total 

(mgn.)

1

<1

-

-

1

Zinc, 

totalrecoverable

(^9/L)

280

350

160

150

400

340

200

2.9

2.9

-

-

-

-

25

Beryllium, 

total 

recoverable 

(mg/L)

<10

<10

-

-

-

-

<10

Carbon, 

organic, 

total

(mg/L)

68

83

-

52

54 Water Quality of Storm Runoff and Comparison of Procedures for Estimating Storm-Runoff Loads, Volume, EventMean Concentrations, and the Mean Load for a Storm for Selected Properties and Constituents for Colorado Springs, 

Southeastern Colorado, 1992
Table 19. Chemical oxygen demand, 5-day biochemical oxygen demand, specific conductance, alkalinity, dissolved solids, 

suspended solids, major ions, nutrients, and total-recoverable metals for storm-runoff sites in Colorado Springs-Continued

Date Time

Oxygen

demend, 

chemical 

(high 

level)

(mg/L)

Oxygen

demand, 

biochemical, 

5 day

(mg/l)

Specific 

conductance 

OiS/cm)

Alkalinity, 

lab 

(mg/L)

Solids, 

dissolved 

(mg/L)

Solids, 

suspended

Calcium, 

dissolved 

(mg/L)

Magnesium, 

dissolved 

(mg/L)

Potassium, 

dissolved 

(mg/L)

Sodium, 

dissolved 

(mg/L)

385118104485801 - Wahsatch Street at Cross Lane (Site 4)

05-26-92

06-03-92

06-12-92

06-26-92

07-25-92

07-29-92

11-21-92

Date

05-26-92

06-03-92

06-12-92

06-26-92

07-25-92

07-29-92

11-21-92

Date

05-26-92

06-03-92

06-12-92

06-26-92

07-25-92

07-29-92

11-21-92

1945

1405

1504

1619

1408

1401

1010

Chloride, 

dissolved 

(mg/L)

-

-

3.0

-

2.1

-

470

Cadmium, 

totairecoversbie 

(M9/L)

<1

1

2

1

<1

1

<!

250

230

500

360

330

340

190

Sulfete, 

dissolved 

(mg/L)

-

6.5

5.6

-

4.5

Chromium, 

totalrecoverable

-

18

8

-

7

-

-

86

72

140

92

29

Nitrogen, 

ammonia, 

total, 

as 

nitrogen 

(mg/L)

1.00

.53

.72

.27

.16

.35

.39

Copper, 

totairecoversbie 

(M9/L)

9

12

22

15

11

17

8

-

84

-

84

82

110

1740

Nitrogen,

ammonia 

plus 

organic, 

total, 

as 

nitrogen

(mg/L)

5.0

4.9

5.3

3.8

3.1

2.8

1.6

Lead, 

totalrecoverebie 

(Mg/L)

41

120

130

130

57

110

32

84

54

-

40

Nitrogen 

nitrite, 

total, 

as 

nitrogen 

(mg/L)

0.05

.06

.07

.04

.03

.04

.08

Mercury, 

totsirecoversble

-

<0.1

<.l

-

<.l

74

132

60

106

93

908

Nitrogen, 

nitrate 

plus 

nitrite, 

total, 

as 

nitrogen 

(mg/L)

0.38

.88

.83

.47

.37

.83

.36

Nickel, 

totalrecoverable

-

11

4

-

4

116

754

660

848

266

512

148

Phosphorus, 

total, 

as 

phosphorus 

(mg/L)

1.20

.47

1.10

.95

.72

.60

.22

Selenium, 

total

-

-

<2

<1

-

<2

~

20

-

11

-

20

Phosphorus, 

dissolved, 

as 

phosphorus 

(mg/L)

-

0.26

.38

.28

.27

.11

Silver, 

totalrecoverebie

-

<\

<1

~

<'

1.3

1.1

-

1.6

Antimony, 

totalrecoverable 

(mg/L)

-

<10

<10

<10

Thsilium, 

total 

(Mg/L)

-

<10

<5

-

<10

5.6

5.3

-

3.7

Arsenic, 

total 

(mg/L)

~

5

-

3

<1

Zinc, 

totairecoverebie

(M9/L)

110

220

300

310

140

240

110

3.3

-

2.2

-

300

Beryllium, 

totsi 

recoverable 

(mg/L)

-

-

<10

-

<10

-

<10

Carbon, 

organic, 

total 

(mg/L)

-

-

100

~

100

~

18

SUPPLEMENTAL DATA 55
Table 19. Chemical oxygen demand, 5-day biochemical oxygen demand, specific conductance, alkalinity, dissolved solids, 

suspended solids, major ions, nutrients, and total-recoverable metals for storm-runoff sites in Colorado Springs-Continued

Date Time

Oxygen

demand, 

chemical 

(high 

level)

(mg/L)

Oxygen

demand, 

biochemical, 

5 day

(mg/l)

Specific 

conductance 

(US/cm)

Alkalinity, 

lab 

(mg/L)

Solids, 

dissolved 

(mgli.)

Solids, 

auapended 

(mg/L)

Calcium, 

dissolved 

(mg/L)

Magnesium, 

dissolved 

(mg/L)

Potassium, 

dissolved 

(mg/L)

Sodium, 

dissolved 

(mg/L)

384935104501501 - Walmart at Eighth Street (Site 5)

06-10-92

06-26-92

07-17-92

08-03-92

08-04-92

08-05-92

12-06-92

Date

06-10-92

06-26-92

07-17-92

08-03-92

08-04-92

08-05-92

12-06-92

Dste

06-10-92

06-26-92

07-17-92

08-03-92

08-04-92

08-05-92

12-06-92

1625

1712

0250

1717

1729

1700

1115

Chloride, 

dissolved 

(mg/L)

-

-

6.9

6.7

-

2000

Cadmium, 

totalrecoverable 

(WJ/L)

3

1

2

21

1

2

4

160

310

200

390

260

200

830

Suifate, 

dissolved 

(mg/L)

--

-

9.2

15

-

-

190

Chromium, 

totalrecoverable 

(MJ/L)

-

-

35

52

-

88

67

260

35

38

71

29

160

Nitrogen, 

ammonia, 

total, 

as 

nitrogen 

(mg/L)

0.58

.52

.41

1.00

1.70

1.00

3.90

Copper, 

totalrecoverable 

(WJ/L)

18

18

15

26

17

30

70

132

100

122

142

91

7010

Nitrogen,

ammonia 

plus 

organic, 

total, 

as 

nitrogen

(mg/L)

1.2

1.8

2.2

2.3

4.2

3.8

7.4

Lead, 

totalrecoverable 

(WJ/L)

340

85

200

300

120

180

350

51

64

-

219

Nitrogen 

nitrite, 

total, 

as 

nitrogen 

(mg/L)

0.06

.10

.03

.04

.08

.04

.31

Mercury, 

totalrecoverable

(ug/L)

-

~

0.1

.2

.1

93

127

70

138

-

67

4240

Nitrogen, 

nitrate 

piua 

nitrite, 

total, 

as 

nitrogen 

(mg/L)

1.0

.71

.69

1.20

1.80

1.20

1.60

Nickel, 

totalrecoverable 

(MJ/L)

-

-

16

21

-

-

33

1400

388

662

872

516

826

1260

Phosphorus, 

total, 

as 

phosphorus 

(mg/L)

0.21

.41

.59

.35

.63

1.00

1.00

nium, 

total 

(H9/L)

-

-

<2

2

-

-

<2

10

14

-

59

Phosphorus, 

dissolved, 

as 

phosphorus 

(mg/L)

0.14

.34

.19

.24

-

.15

.09

Silver, 

totalrecoverable

(ng/L)

-

-

<1

<1

-

-

<1

1.1

1.4

16

Antimony, 

totalrecoverable 

(mg/L)

-

-

<10

<10

-

-

<10

Thallium, 

total

(ng/L)

-

-

<5

<5

-

<5

2.2

2.7

-

3.2

Arsenic, 

total 

(mg/L)

-

-

5

7

-

-

13

Zinc, 

totsirecoverabie

(ng/L)

500

210

330

630

340

330

730

6.2

4.9

1300

Beryllium, 

total 

recoverable 

(mg/L)

-

-

<10

<10

-

-

<10

Carbon, 

organic, 

total 

(mg/L)

-

~

69

77

-

-

240

56 Water Quality of Storm Runoff and Comparison of Procedures for Estimating Storm-Runoff Loads, Volume, EventMean Concentrations, and the Mean Load for a Storm for Selected Properties and Constituents for Colorado Springs, 

Southeastern Colorado, 1992
 «

III!" m -

Ilslf 5 « £ &

ill

CQ eg

iJll Q> ^ +* ^

ggs

,2=55

<°s| 45 c

ila

0) pS

.poo 

£> o o o

i v v "v

o o o

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o o o

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o o o

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^H ^H {<)

pop 

o o o 1 1 1 1 1 1

V V V

o o o

O -4 O * 1 * 1 * 1 v

0 0 0

* O p p 

S o o O

I v v v

35

oop

3 p p p "9 "9 "9

poo 9 -9 -9

o o o

"9 "9 "9

f<> O O

es * m ^ oo o> 1-1 O O

g 8

<r> O

r- oo

O O

0) P 0) o

I o =5 "

S

c

ills

If!

D aD Q.

0) c

8=-"

o o o

 9 "9 "9

O 0 O

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<=><=><=> "9 "9 "9

p p q

^H wS -^

es es 1-1 .

vo 2

o o o

000

v V v

o o o

"9 "9 "9

O O 0

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O p p

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~ V

O O 0

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- - tS (S o\ o\ o\

O 1-1

. O Z2 O -H

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c"

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w

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Ijl

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eg O

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pop

pop

r*"> r*"> c^ V V V

o o o

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o o o

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0 O O

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O O 0

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o o o

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pop "9 "9 "9

pop "9 "9 "9

pop 

v *"" "v

o o o

"9 "9 "9

(S (S (S o\ o\ o\

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cs ^^ es

00 -i

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SUPPLEMENTAL DATA 57
1s

CM 0.

o |s

6 i

o £ o>~ cu

m

8=5 

~2 

si

o

* i 58!

o

w

P

"5 = 

c fi

Q. **

i

000 9

0 O O

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q q q

o o o'

V V V

O 0 0

"9 "9

u

o

p

a

i, q q p

-9 X? -9

o o o

"9 "9 "9

o o o

-9 -9 X)

q o. p

<n >n >n

V V V

o o o 

i~ o\ od

t-~ oo , 1

0 O ^H

* o"

ill

"E » O

I**!:

5 0.0.

s

till cJ c o **

6 |-

w « a-**

till CM = §.-

E a.

S -

q q q

000 9 -9 -9

o o o

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000

o o o

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o o o

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q q q

q q q

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O 0 O

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S (S (S

^ ON 0V

I I I

,-~ ao r« O O ^H

41OL.&

I

q q q

<ri <ri <n

V V V

q q q

>n >n' >n

V V V

q q q

V) Q O

(S S\ "H

o q q

!-< C*l O

o o o

o * o'

^H -H rH

V V

o o o 

is \d o

°. °. §

2 R S

o o o

? ? ?

v v v

q q q

* S "9

o o o

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000 9 -9 -0

<n * o

>n (S i i

2 E S

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fl i i (S I I I

tri \o i i

58 Water Quality of Storm Runoff and Comparison of Procedurea for Estimating Storm-Runoff Loads, Volume, Event-Mean Concentrations, and the Mean Load for a Storm for Selected Properties and Constituents for Colorado Springs, Southeastern Colorado, 1992
« 2 

*

I O TJ

"

i

i 8.

§£I

Q caIr

Q O.

">. ®

Q 0. 8PoiQ

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"9 "9 "Q

000 "9 "9 "Q

000 "9 "9 "Q S

S

a °. P. P.

pop

 g o o o

v v v

3 p p p

j, "Q "Q "Q

0 0 0

o o o

^ i-< O CO VO -HV

o o o

 9 -9 -9

< < ON i I

CO ^1 C^l S

^ *"*

^3 ^H

I

'Si

p 5.1- c o

nt«S

|«-s l^S:' Q

pop "' S '

000

oddv

pop

odd

o o o -Q "Q

"Q

o o o

 9 -9 -9

000

"0 tf

000 9 -0 -9

o o o -Q -9

P P P *o *o

v v

000

s o( d

0 O O

 9 -9 -9

rt ON rt

CO -H fv|

S i

5

* A

Ill

-

ilmtf

!s8 fe'-ttf A

lfill

00

c 9 o

« £ g 

S 3 « 8 g

I"!

Q.

0) Q

000 9

pop 

>n m m V V V

 9 -9 "Q

0 0 O

odd

V V V

 9 -9 -9

o o o

 9 -9 -9

000 9 -9 "Q

000 9 V -9

O O 0

 9 -9 -9

pop

V *V *V

O O 0

 * vd

V) ^

0

! i

<Y V S1 

S S ^

o c c 

2

311 i

CM c O

o o.

CM" § §.-

000

odd

V V V

o o o 

odd

o o q

>n >n >n

V V V

o o o

 9 -9 "9

000

o o o

 9 "9 "9

000 9 "9 "9

odd 

cs cs cs V V V

000

odd

pop 

>n >n >n 

V V V

pop 

>n >n >n 

V V V

>n o -

O O -H

SUPPLEMENTAL DATA 59
o>

o

Table 20. Selected acid-base/neutral organic compounds for storm-runoff sites in Colorado Springs-Continued

Water Quality ofStorm ions, andtheMean Lot

Runoff andC

ad fora Storm

omparison of

for Selected

If

1. a.

» 3

tt w 

0.0

O m

stimating Stornonstituents for

O -f

2L3J

3 =

wo"

 o.

5."

*£

ume, Event 

ioutheastei

-, ,

of

3 o

o. o

o ^

-1

si

Date

06-05-92 

06-19-92 

11-11-92

Date

06-05-92

06-19-92

11-11-92

Date

06-05-92

06-19-92

11-11-92

Date

06-05-92

06-19-92

11-11-92

Time

1240 

1735 

0759

Benzo- Bena-an- zogh-lAce- Ace- ... _ thra- Benzo- peryl- Benzo- 

. . Anthra- Benzi- . . , V. . ._ ,, 

naph- naph- cene djne cenel, 2- a- enel, 12- b-fluorthylene, thene, . ' ' benz- pyrene, benzo- anthene 

total total anthra- total peryl- total 

cene, ene, 

total total

<5.0 

<5.0 

<5.0

Bis (2-

"SET «S7

ether,

total

<5.0

<5.0

<5.0

Hexachloroethane, 

total

<5.0

<5.0

<5.0

Phenol, 

total

_

<5.0

22.0

23.0

<10.0

Indeno 

(1,2,3-cd) 

pyrene, 

total

38.0

<10.0

<10.0

Pyrene, 

total

32.0

32.0

<5.0

385240104493601 - Beacon Street at Bucnanan Street (Site 3) 

<5.0 5.0 <40.0 <10.0 12.0 31.0 17.0 

<5.0 <5.0 <40.0 10.0 15.0 <10.0 26.0 

<5.0 <5.0 <40.0 <10.0 <10.0 <10.0 <10.0

Di-ethyl- Dl-methylphthalate, phthalate, 

total total

<5.0

<5.0

<5.0

iso- Naphphorone, thalene, 

total total

<5.0 <5.0

<5.0 <5.0

<5.0 <5.0

Benzene- 1 -M|- Dhenv|. 

o-chloro- p"e,nyi

hydrawater *

 - I ±,

 S. *>«"-

erable . . 

erable

<5.0 <5.0

<5.0 <5.0

<5.0 <5.0

<5.0

<5.0

<5.0

N-butyl 

benzyl 

phthalate, 

total

<5.0

<5.0

<5.0

Benzene,

1,2,4-trlchlorobenzene, 

unflltered,

recoverable

<5.0

<5.0

<5.0

Dl-n-octylphthalate, 

total

<10.0

<10.0

<10.0

Nitrobenzene, 

total

<5.0

<5.0

<5.0

Benzene,

1,2-dlchlorowater, 

unfiltered,

recoverable

<5.0

<5.0

<5.0

. 

""or- 

, . 

tota 

14.0 

30.0 

<10.0 

Dl-n-butyl- Fluorphthalate, anthene, 

total total

<5.0

<5.0

<5.0

N-nltrosodl-npropylamine, 

total

<5.0

<5.0

<5.0

Benzene,

1,3-dlchlorowater, 

unflltered,

recoverable

<5.0

<5.0

<5.0

45.0

45.0

<5.0

N-nltrosodlmethylamlne, 

total

<5.0

<5.0

<5.0

Benzene,

1,4-dlchlorowater, 

unflltered,

recoverable

<5.0

<5.0

<5.0

N-nltrosodlphenylamine, 

total

<5.0

<5.0

<5.0

 Hr

<10.0

<10.0

<10.0

<

<

<
ii

i e o 5 ~

..o--- 

2 c 1 « 5

fit*5

l

A-!. -_ 

2 N fl> «

? s g « *.sS2

CM C O

5 'III

 -r 

I E g 75 sit 2

f" c _c *S 

« !* *

 i A 7f_ 2 «lt 

S 1«9 Q

-

o o o 

odd

o o o 

o o o

o o o

 0

o o o

o o o

 55 o o o

^ p p p

g 0 0 O 

O O O

o o o

O O 0

 Q -Q -Q

<N CS (N|

C[\ O\ o\

 t T

^ ^ < *

m O r" f* 

a-s ??

ti .,113 * ** o

.2 §52* 

4 j.?! AJ. .-

o o o

000

0 0 0 

PO f~ 2

pop

^00 "* V "v

pop 

IT! d d

 ^ v V

S

53, p p p odd ^H » t < t

V V V

^ q q p a .- d d r vv

o o o

o d d

V V V

o o o 

d d d

pop

$ \j V

o o o

"9

o o o

 Q

r3 cjJ

B s

" M

£5

ate, 

l

Dl-n-b phthal

Q 0.

0 O O

 0

o o o

O O 0

 Q -Q -Q

pop 

i-« <o

<-> V

o o o

X?

pop

odd

V V V

o o o

 o

0 O O

"0

o p p

r-' d d

"v "v

o o o

CS »T) < 1 

 « M CS

ill «**

i-S « f £ £ S

elif 3

allg!

o c o

Cr

. ^

C C B

« C 0

 af- £

z

A S « £ 3S

*-5

2 -0 0.

ils

000 

rn r-' >n 

(S V

pop 

odd

~ m m 

V V

o o o 

odd

w w wo 

V V V

000 

tf V

O O 0

o o o

 9

o o o

 9 "0 'Q

V) iri uS 

V V V

pop Q V

o o o 

odd

V V V

(N <N

Ov Ov

 i S CS

S s

SUPPLEMENTAL DATA 61
o>

N> Table 20. Selected acid-base/neutral organic compounds for storm-runoff sites in Colorado Springs-Continued

§f » »

Quality of

and theMi

M tfi

§ ff

s ^

2; c

?i

2 3

O Q.

Date

06-12-92

07-25-92

11-21-92

Phenol, Pyrene, 

total total

24.0

9.0

<5.0 <5.0

Benzene

o-chioro 

water 

unfiltered,

recoverable

<5.0

<5.0

<5.0

1,2-dlphenylhydrazlne, 

water, 

totalrecoverable

385118104485801

<5.0

<5.0

<5.0

Benzene,

1,2,4-trlchlorobenzene, 

unfiitered,

recoverable

Benzene,

1,2-dlchlorowater, 

unflltered,

recoverable

Benzene, 1,3-

di-chlorowater, 

unfiltered,

recoverable

Benzene,

1,4-dlchlorowater, 

unflltered,

recoverable

anthracene,

total

- Wahsateh Street and Cross Lane (Site 4)-Continued

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<5.0

<10.0

<10.0

<10.0

8

in of Procedl sted Propertii

3 3

0, 0>

a°

II

c ~

|«

« (0

orm-Runc For Colora

Q. &

o =*

If

w -

f i

7 A

3 c"

Date

06-12-92

07-25-92

11-21-92

Date

2,4-dlchlorophenol, 

total

<5.0

<5.0

<5.0

Time

2,4-dl- 2,4-dlmethyi- nitrophenol, phenol, 

total total

<5.0 <20.0

<5.0 <20.0

<5.0 <20.0

Sa. *«£- ^-

thylene, thene, total' 

total total

2,4,6-trichiorophenol, 

total

<20.0

<20.0

<20.0

Benzl2,4-dlnltrotoluene, 

total

<5.0

<5.0

<5.0

Benzo-aanthracenel, 2- 

benzanthracene,

total

2,6-dlnitrotoluene, 

total

<5.0

<5.0

<5.0

Benzo-apyrene, 

total

3,3-dlchlorobenzl-dln 

total

<20.0

<20.0

<20.0

Benzogh-lperylenei, 12- 

benzoperylene,

total

4-bromo- 4

phenyi- p

phenol, p

e> ether, 

total 

<5.0 

<5.0 

<5.0 

Benzo-b- Benzo-k- 

fluor- fluor- 

anthene, anthene, 

total total 

384935104501501 - Wahnart at Eighth Street (Site 5)

07-17-92

08-03-92

12-06-92

0250

1717

1115

<5.0 <5.0 <5.0

<5.0 <5.0 <5.0

<5.0 <5.0 9.0

<40.0

<40.0

<40.0

<10.0

<10.0

<10.0

<10.0

<10.0

<10.0

<10.0

<10.0

<10.0

<10.0 <10.0 

<10.0 <10.0 

<10.0 <10.0 

p s

 I

ro S
l

Illl if *-

^£

 >>« f SO CB < IfO Q.

*ll

It*"

i-l f * s Sffi

0)§«

. . f s 

as g-s sill

m a!

4)

15Q

O O O

X? X? X?

o o o

x? x? x?

pop

X? X? X>

pop 

o * 

 « 0 0 O 

- r^ vd

o o o 

3 o o ~

g O p p

n in in IT!

-. v V V

p q o

X? X? X?

pop

o o d "v "v "v

q p p

r- oo CM

O O i

IIII2

z!2

i|l

Q.

° 

o o o 

odd

o o o

000

o o o

 9

o o o

O 0 0

 9 V V

o o o

</ ) VO i-< V 

o o o

o o o

000

d d d "v "v "v

o o o

-o

-r 9

OO

o o

ii

6 A 

of g «

Sf"

isitfi

S.8£8S

istfiftf - _e 5 5 4> S % 

S i A --.

i 5 £ S" i i g j: o § t * o

11 hi II

. A m- - j. i *

V CD o

s

1 o

o o o

o o o

 Q -Q -9

o o o

o o o

odd

V V

000

x; ti

o o o

X? X? X?

P Q o

X? "9 X?

X? "0 X?

pop

X? X? X?

p p o

>r> >r> in

V V V

pop

00 CN O

ra ra ra o\

OO CN

00 

Illp

8-- -

o g-g feg

c. 5 5 £ o o £ £ a *

c c -.

4> 4> t £ £ « 

Q. O.£

-! 6 -! 1

sii!

w c 75

ci = o

Ji

1

CM £ §. SS

pop

COv

O O O

dd

CO CO

V V

O O O

X? X? X?

P P P

X? X? X?

o o o

pop

X? X? X?

o o o

pop 

odd

o o o 

dd

04 04 

V V V

p p q

in in vi

V V V

o o o

X? X? X?

oo CN

O O 

SUPPLEMENTAL DATA 63
Table 21. Selected pesticide compounds for storm-runoff sites in Colorado Springs 

[All concentrations in micrograms per liter; <, less than]

Date

BHC 

Alpha,

Aroclor, PCB, total

1016 1221 1232 1242 1248 1254 1260

38491810445201 - Sixteenth Hole, Valley-Hi Golf Course (Site 1)

07-25-92 1423 <0.04 <0.03 <0.1 <1.0 <0.1 <0.1 <0.1

08-10-92 0840 <.04 <.03 <.l <1.0 <.l <.l <.l 

11-21-92 0930 <.04 <.03 <.l <1.0 <.l <.l <.l

Date

07-25-92

08-10-92

11-21-92

Betabenzene, 

hexachloride, 

total

<0.03

<.03

<.03

Chlordane, 

cis, 

water, 

whole,

total

<0.10

<.10

<.10

Chior2T S

« SJ

total

<0.1 <0.10

<.l <.10

<.l <.10

Delta, 

benzene, 

hexachlorlde, 

total

<0.09

<.09

<.09

Dleldrln, 

total

<0.02

<.02

<.02

Endosulfanbeta, 

total

<0.04

<.04

<.04

Endosulfan 1, 

Alpha, 

water, 

whole, 

recoverable

<0.10

<.10

<.10

Endosulfan, 

sulfate, 

total

<0.60

<.60

<.60

Date

07-25-92

08-10-92

11-21-92

Endrin, 

aldehyde, 

total

<0.20

<.20

<.20

Endrin

water, 

unflltered, 

recoverable

<0.06

<.06

<.06

Gamma, 

BHC, 

Lindane, 

total

<0.03

<.03

<.03

Heptachlor, 

total

<0.03

<.03

<.03

Heptachiorepoxide, 

total

<0.80

<.80

<.80

Toxaphene, 

total

<2

<2

<2

P,P' 

DDD, 

total

<0.10

<.10

<.10

p,p'

DDE, 

totsl

<0.04

<.04

<.04

P,P' 

DOT, 

total

<0.10

<10

<10

64 Water Quality of Storm Runoff and Comparison of Procedures for Estimating Storm-Runoff Loads, Volume, EventMean Concentrations, and the Mean Load for a Storm for Selected Properties and Constituents for Colorado Springs, 

Southeastern Colorado, 1992
Table 21. Selected pesticide compounds for storm-runoff sites in Colorado Springs-Continued

Date Time Aldrln, 

total

BHC

Alpha,

total

Aroclor, PCB, total

1016 1221 1232 1242 1248 1254 1260

385347104500601 - Chestnnt Street at Donglas Creek (Site 2)

05-31-92 1255 <0.04 <0.03 <0.1 <1.0 <0.1 <0.1

06-19-92 1728 <.04 <.03 <.l <1.0 <.l <.l 

11-21-92 0910 <.04 <.03 <1 <1.0 <.l <.l

Date

05-31-92

06-19-92

11-21-92

Betabenzene, 

hexachlorlde, 

total

<0.03

<.03

<.03

Chlordane, els, Chlorwater, dane, 

whole, total 

total

<0.10 <0.1

<.10 <.l

<.10 <.l

Chlordane, 

trans, 

water, 

whole, 

total

<0.10

<.10

<.10

Delta, 

benzene, 

hexachlorlde, 

total

<0.09

<.09

<.09

Dleldrln, 

total

<0.02

<.02

<.02

Endosulfanbeta, 

total

<0.06

<.04

<.04

Endosulfan 1, 

Alpha, 

water, 

whole, 

recoverable

<0.10

<.10

<10

Endosulfan, 

sulfate, 

total

<0.60

<.60

<.60

Date

05-31-92

06-19-92

11-21-92

Endrin, 

aldehyde, 

totel

<0.20

<.20

<.20

Endrin

water, 

unflltered, 

recoverable

<0.06

<.06

<.06

Gamma, 

BHC, 

Llndane, 

total

<0.03

<.03

<.03

Heptachlor, 

total

<0.03

<.03

<.03

Heptachlorepoxlde, 

total

<0.80

<.80

<.80

Toxaphene, 

total

<2

<2

<2

P,P' 

DDD, 

total

<0.10

<.10

<.10

p,p'

DDE, 

total

<0.04

<.04

<.04

P,P' 

DOT, 

total

<0.10

<.10

<.10

SUPPLEMENTAL DATA 65
Table 21. Selected pesticide compounds for storm-runoff sites in Colorado Springs-Continued

Date Time Aldrin, 

total

BHC

Alpha,

total

Aroclor, PCB, total

1016 1221 1232 1242 1248 1254 1260

385240104493601 - Beacon Street at Buchanan Street (Site 3)

06-05-92 1240 <0.04 <0.03 <0.1 <1.0 

06-19-92 1735 <.04 <.03 <.l <1.0 

11-11-92 0759 <.04 <.03 <.l <1.0

Date

06-05-92

06-19-92

11-11-92

Betabenzene, 

hexachlorlde, 

total

<0.03

<.03

<.03

Chlordane, els, Chlorwater, dane, 

whole, total 

total

<0.10 <0.1

<.10 <.l

<.10 <.l

Chlordane, 

trans, 

water, 

whole,

total

<0.10

<.10

<.10

Delta, 

benzene, 

hexachlorlde, 

total

<0.09

<.09

<.09

Dleldrln, 

total

<0.020

<.020

<.020

Endosulfanbeta, 

total

<0.04

<.04

<.04

Endosulfan 1, 

Alpha, 

water, 

whole, 

recoverable

<0.10

<.10

<.10

Endosulfan, 

sulfate, 

total

<0.60

<.60

<.60

Date

06-05-92

06-19-92

11-11-92

Endrln, 

aldehyde, 

total

<0.20

<.20

<.20

Endrln

water, 

unflltered, 

recoverable

<0.06

<.06

<.06

Gamma, 

BHC, 

Llndane, 

total

<0.03

<.03

<.03

Heptachlor, 

total

<0.03

<.03

<.03

Heptachlorepoxlde, 

total

<0.80

<.80

<.80

Toxaphene, 

total

<2

<2

<2

P,P' 

DDD, 

total

<0.10

<.10

<.10

p,p'

DDE, 

total

<0.04

<.04

<.04

P,P' 

DOT, 

total

<0.10

<.10

<.10

66 Water Quality of Storm Runoff and Comparison of Procedures for Estimating Storm-Runoff Loads, Volume, EventMean Concentratlona, and the Mean Load for a Storm for Selected Properties and Constituents for Colorado Springs, 

Southeastern Colorado, 1992
Table 21 . Selected pesticide compounds for storm-runoff sites in Colorado Springs-Continued

Date Time Aldrln, 

total

BHC

Alpha, 

total 1<»6 1221

Aroclor, PCB, total

1232 1242 1248 1254 1260

385118104485801 - Wahsatch Street at Cross Lane (Site 4)

06-12-92

07-25-92

11-21-92

1504

1408

1005

<0.040

<.040

<.040

<0.03 <0.1 <1.0

<.03 <.l <1.0

<.03 <.l <1.0

<0.1 <0.1 <0.1

<.l <.l <.l

<.l <.l <.l

<0.1 <0.1

<.l <.l

<.l <.l

Date

06-12-92

07-25-92

11-21-92

Betabenzene, 

hexachlorlde, 

total

<0.03

<.03

<.03

Chlordane, els, 

water, 

whole, 

total

<0.10

<.10

<.10

Chlordane, 

total

0.2

<.l

<.l

Chlordane, 

trans, 

water, 

whole,

total

<0.10

<.10

<.10

Delta, 

benzene, 

hexachlorlde, 

total

<0.09

<.09

<.09

Dieldrln, 

total

<0.02

<.02

<.02

Endosulfanbeta, total

<0.04

<.04

<.04

Endosulfan 1, 

Alpha, 

water, 

whole, 

recoverable

<0.10

<.10

<.10

Endosulfan, 

sulfate, 

total

<0.60

<.60

<.60

Date

06-12-92

07-25-92

11-21-92

Endrln, 

aldehyde, 

total

<0.20

<.20

<.20

Endrln

water, 

unfiltered, 

recoverable

<0.06

<.06

<.06

Gamma, 

BHC, 

Llndane, 

total

<0.03

<.03

<.03

Heptachlor, 

total

<0.03

<.03

<.03

Heptachlorepoxlde, 

total

<0.80

<.80

<.80

Toxaphene, 

total

<2

<2

<2

P,P' 

DDD, 

total

<0.10

<.10

<.10

p,p'

DDE, 

total

<0.04

<.04

<.04

P.P' 

DOT, 

total

<0.10

<.10

<.10

SUPPLEMENTAL DATA 67
Table 21. Selected pesticide compounds for storm-runoff sites in Colorado Springs-Continued

Date Time Aldrin, 

total

BHC

Alpha,

total

Aroclor, PCB, total

1016 1221 1232 1242 1248 1254 1260

384935104501501 - Walmart at Eighth Street (Site 5)

07-17-92 0250 <0.04 <0.03 <0.1 <1.0 <0.1 <0

08-03-92 1717 <.04 <.03 <.l <1.0 <.l < 

12-06-92 1115 <.04 <.03 <.l <1.0 <.l <

Date

07-17-92

08-03-92

12-06-92

Betabenzene, 

hexachloride, 

total

<0.20

<.03

<03

Chlordane, els, 

water, 

whole, 

total

<0.060

<.10

<.10

Chlordane, 

total

<0.030

<.l

<.l

Chlordane, 

trans, 

water, 

whole,

total

<0.030

<10

<10

Delta, 

benzene, 

hexachloride, 

total

<0.80

<.09

<.09

Dleldrln, 

total

<0.02

<.02

<.02

Endosulfanbeta, 

total

<0.10

<.04

<.04

Endoaulfan 1, 

Alpha, 

water, 

whole, 

recoverable

<0.04

<.10

<10

Endosulfan, 

sulfate, 

total

<0.10

<.60

<.60

Date

07-17-92

08-03-92

12-06-92

Endrln, 

aldehyde, 

total

<0.20

<.20

<.20

Endrln

water, 

unfiltered, 

recoverable

<0.06

<.06

<.06

Gamma, 

BHC, 

Llndane, 

total

<0.03

<03

<.03

Heptschlor, 

total

<0.03

<.03

<.03

Heptachiorepoxlde, 

total

<0.80

<.80

<.80

Toxaphene, 

total

<2

<2

<2

P.P' 

DDD, 

total

<0.10

<10

<.10

P.P' 

DDE, 

total

<0.04

<.04

<.04

P.P' 

DOT, 

total

<0.10

<.10

<.10

68 Water Quality of Storm Runoff and Comparison of Procedures for Estimating Storm-Runoff Loads, Volume, EventMean Concentrations, and the Mean Load for a Storm for Selected Properties and Constituents for Colorado Springs, 

Southeastern Colorado, 1992

ir U.S. GOVERNMENT PRINTING OFFICE: 1995 - 673-211 / 00022 REGION HO.