U.S. GEOLOGICAL SURVEY

Water-Resources Investigations Report 

Traveltime Characteristics of Gore Creek 

and Black Gore Creek, Upper Colorado 

River Basin, Colorado

By Jason J. Gurdak, Norman E. Spahr, and Richard J. Szmajter

Denver, Colorado

2002

02 –4037

NATIONAL WATER-QUALITY ASSESSMENT PROGRAM
U.S. DEPARTMENT OF THE INTERIOR

GALE A. NORTON, Secretary

U.S. GEOLOGICAL SURVEY

Charles G. Groat, Director

The use of firm, trade, and brand names in this report is for identification purposes only and does

not constitute endorsement by the U.S. Geological Survey.

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

U.S. Geological Survey

Information Services

Box 25286

Denver Federal Center

Denver, CO 80225

from:

District Chief

U.S. Geological Survey

Box 25046, Mail Stop 415

Denver Federal Center

Denver, CO 80225-0046
FOREWORD

The mission of the U.S. Geological Survey 

(USGS) is to assess the quantity and quality of the 

earth resources of the Nation and to provide information that will assist resource managers and policymakers at Federal, State, and local levels in making sound 

decisions. Assessment of water-quality conditions and 

trends is an important part of this overall mission.

One of the greatest challenges faced by waterresources scientists is acquiring reliable information 

that will guide the use and protection of the Nation’s 

water resources. That challenge is being addressed by 

Federal, State, interstate, and local water-resource 

agencies and by many academic institutions. These 

organizations are collecting water-quality data for a 

host of purposes that include: compliance with permits 

and water-supply standards; development of remediation plans for specific contamination problems; operational decisions on industrial, wastewater, or watersupply facilities; and research on factors that affect 

water quality. An additional need for water-quality 

information is to provide a basis on which regionaland national-level policy decisions can be based. Wise 

decisions must be based on sound information. As a 

society we need to know whether certain types of 

water-quality problems are isolated or ubiquitous, 

whether there are significant differences in conditions 

among regions, whether the conditions are changing 

over time, and why these conditions change from 

place to place and over time. The information can be 

used to help determine the efficacy of existing waterquality policies and to help analysts determine the 

need for and likely consequences of new policies.

To address these needs, the U.S. Congress appropriated funds in 1986 for the USGS to begin a pilot program in seven project areas to develop and refine the 

National Water-Quality Assessment (NAWQA) Program. In 1991, the USGS began full implementation of 

the program. The NAWQA Program builds upon an 

existing base of water-quality studies of the USGS, as 

well as those of other Federal, State, and local agencies. 

The objectives of the NAWQA Program are to:

• Describe current water-quality conditions for a 

large part of the Nation’s freshwater streams, 

rivers, and aquifers.

• Describe how water quality is changing over 

time.

• Improve understanding of the primary natural 

and human factors that affect water-quality

conditions.

This information will help support the development 

and evaluation of management, regulatory, and monitoring decisions by other Federal, State, and local 

agencies to protect, use, and enhance water resources. 

The goals of the NAWQA Program are being 

achieved through ongoing and proposed investigations 

of 59 of the Nation’s most important river basins and 

aquifer systems, which are referred to as study units. 

These study units are distributed throughout the 

Nation and cover a diversity of hydrogeologic settings. 

More than two-thirds of the Nation’s freshwater use 

occurs within the 59 study units and more than twothirds of the people served by public water-supply systems live within their boundaries.

National synthesis of data analysis, based on 

aggregation of comparable information obtained from 

the study units, is a major component of the program. 

This effort focuses on selected water-quality topics 

using nationally consistent information. Comparative 

studies will explain differences and similarities in 

observed water-quality conditions among study areas 

and will identify changes and trends and their causes. 

The first topics addressed by the national synthesis are 

pesticides, nutrients, volatile organic compounds, and 

aquatic biology. Discussions on these and other waterquality topics will be published in periodic summaries 

of the quality of the Nation’s ground and surface water 

as the information becomes available.

This report is an element of the comprehensive 

body of information developed as part of the NAWQA 

Program. The program depends heavily on the advice, 

cooperation, and information from many Federal, 

State, interstate, Tribal, and local agencies and the 

public. The assistance and suggestions of all are 

greatly appreciated.

Robert M. Hirsch

Chief Hydrologist

FOREWORD III
CONTENTS V

CONTENTS

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

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

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

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

Acknowledgments ....................................................................................................................................................... 4

Theory and Methods for Determination of Traveltime and Longitudinal-Dispersion Characteristics.................................. 4

Tracer Theory............................................................................................................................................................... 5

Traveltime .......................................................................................................................................................... 5

Longitudinal Dispersion .................................................................................................................................... 6

Methods Used in the Gore Creek Watershed............................................................................................................... 6

Traveltime .............................................................................................................................................................................. 7

Traveltime Measurements............................................................................................................................................ 7

Estimated Traveltimes.................................................................................................................................................. 8

Traveltime Estimation Example................................................................................................................................... 10

Longitudinal-Dispersion Coefficients.......................................................................................................................... 12

Summary................................................................................................................................................................................ 13

References Cited.................................................................................................................................................................... 14

FIGURES

1. Map showing location of study area and dye injection and sampling sites in the Gore Creek watershed ................. 3

2–4. Graphs showing:

2. Typical dye response curves resulting from an instantaneous upstream injection of tracer .............................. 5

3. Daily mean discharge for Black Gore Creek and Gore Creek during water year 1997..................................... 7

4. Dye response curves, May 21 and September 25, 1997 .................................................................................... 9

TABLES

1. Traveltime sites on Black Gore Creek and Gore Creek, Colorado ......................................................................... 4

2. Traveltime data for the May 20 and 21, 1997, dye injections................................................................................. 8

3. Traveltime data for the September 24–26, 1997, dye injections............................................................................. 9

4. Estimated traveltimes of peak dye concentration in Black Gore Creek and Gore Creek, Colorado....................... 11

5. Estimated traveltimes of peak dye concentration in Gore Creek, Colorado ........................................................... 11

6. Longitudinal-dispersion coefficients (Kx) for selected stream reaches on Black Gore Creek and 

Gore Creek, Colorado.............................................................................................................................................. 13
VI CONTENTS

CONVERSION FACTORS AND ABBREVIATIONS

ADDITIONAL ABBREVIATIONS OR TERMS

mg/L, milligrams per liter

mL, milliliters

Q, discharge

s, seconds

μg/L, micrograms per liter

>, greater than

Multiply By To obtain

foot (ft) 0.3048 meter

foot per second (ft/s) 0.3048 meter per second

square foot per second (ft2/s) 0.0929 square meter per second

mile per hour (mph) 1.609 kilometer per hour

cubic foot (ft3

) 0.02832 cubic meter

gallon (gal) 3.785 liter

cubic foot per second (ft3

/s) 0.02832 cubic meter per second 

cubic foot per second (ft3

/s) 28.32 liter per second

square mile (mi2) 2.59 square kilometer 

pound (lb) 0.454 kilogram
Abstract 1

Traveltime Characteristics of Gore Creek and Black 

Gore Creek, Upper Colorado River Basin, Colorado

By Jason J. Gurdak, Norman E. Spahr, and Richard J. Szmajter

Abstract

In the Rocky Mountains of Colorado, major 

highways are often constructed in stream valleys. 

In the event of a vehicular accident involving 

hazardous materials, the close proximity of highways to the streams increases the risk of contamination entering the streams. Recent population 

growth has contributed to increased traffic volume 

along Colorado highways and has resulted in 

increased movement of hazardous materials, 

particularly along Interstate 70. 

Gore Creek and its major tributary, Black 

Gore Creek, are vulnerable to such contamination 

from vehicular accidents along Interstate 70. Gore 

Creek, major tributary of the Eagle River, drains 

approximately 102 square miles, some of which 

has recently undergone significant urban development. The headwaters of Gore Creek originate in 

the Gore Range in the eastern part of the Gore 

Creek watershed. Gore Creek flows west to the 

Eagle River. Beginning at the watershed boundary 

on Vail Pass, southeast of Vail Ski Resort, Interstate 70 parallels Black Gore Creek and then 

closely follows Gore Creek the entire length of 

the watershed. Interstate 70 crosses Gore Creek 

and tributaries 20 times in the watershed. 

In the event of a vehicular accident 

involving a contaminant spill into Gore Creek or 

Black Gore Creek, a stepwise procedure has been 

developed for water-resource managers to estimate traveltimes of the leading edge and peak 

concentration of a conservative contaminant. An 

example calculating estimated traveltimes for a 

hypothetical contaminant release in Black Gore 

Creek is provided.

 Traveltime measurements were made 

during May and September along Black Gore 

Creek and Gore Creek from just downstream from 

the Black Lakes to the confluence with the Eagle 

River to account for seasonal variability in stream 

discharge. Fluorometric dye injection of 

rhodamine WT and downstream dye detection by 

fluorometry were used to measure traveltime 

characteristics of Gore Creek and Black Gore 

Creek. During the May traveltime measurements, 

discharges ranged from 82 cubic feet per second 

(ft3/s) at Black Gore Creek near Minturn (U.S. 

Geological Survey station number 09066000) to 

724 ft3/s at Gore Creek at mouth near Minturn 

(U.S. Geological Survey station number 

09066510), whereas during the September traveltime measurements, discharges ranged from 

3.6 ft3

/s at Black Gore Creek near Minturn to 

62 ft3/s at Gore Creek at mouth near Minturn. 

Cumulative traveltimes for the peak dye concentration during the May traveltime measurements 

ranged from 3.45 hours (site 1 to site 3) in Black 

Gore Creek to 2.50 hours (site 8 to site 12) in 

Gore Creek, whereas cumulative traveltimes for 

the peak dye concentration during the September 

traveltime measurements ranged from 15.33 hours 

(site 1 to site 3) in Black Gore Creek to 8.65 hours 

(site 8 to site 12) in Gore Creek. During the 

September dye injections, beaver dams on Black 

Gore Creek, between site 1 and the confluence 

with Gore Creek, substantially delayed movement 

of the rhodamine WT. 
2 Traveltime Characteristics of Gore Creek and Black Gore Creek, Upper Colorado River Basin, Colorado

Estimated traveltimes were developed using 

relations established from linear-regression 

methods of relating measured peak traveltime to 

discharge during those measurements, which 

were obtained at Black Gore Creek near Minturn 

and Gore Creek at mouth near Minturn. Resulting 

estimated peak traveltimes for Black Gore Creek 

(sites 1 to 5) ranged from 5.4 to 0.4 hour for 20 to 

200 ft3/s and for Gore Creek (sites 5 to 12), 5.5 to 

0.3 hour for 20 to 800 ft3

/s. 

Longitudinal-dispersion coefficients that 

were calculated for selected stream reaches 

ranged from 17.2 square feet per second at 4 ft3/s 

between sites 2 and 3 to 650 square feet per 

second at 144 ft3/s between sites 7 and 8. Longitudinal-dispersion coefficients are necessary variables for future stream-contaminant modeling in 

the Gore Creek watershed. 

INTRODUCTION

In the Rocky Mountains of Colorado, major 

highways are often constructed in stream valleys. In 

the event of a vehicular accident involving hazardous 

materials, the close proximity of highways to the 

streams increases the risk of contamination entering 

the streams. Such a spill could have a deleterious 

effect on downstream water-quality conditions. 

Recent population growth has contributed to 

increased traffic volume along Colorado highways and 

has resulted in increased movement of hazardous 

materials, particularly along Interstate 70. Vehicular 

accidents involving hazardous materials are more 

likely to occur in variable driving conditions, which 

are particularly common in mountainous regions. Low 

grade highways constructed in stream valleys typically 

become more steep closer to the headwaters and typically traverse a mountain pass. Mountain passes 

present significant driving challenges, as these steeply 

graded and winding roads often are subject to poor 

driving conditions due to wind, snow, and ice.

 Population growth also puts extra demands on 

the quality and quantity of water resources. Mountain 

communities commonly rely on surface water for 

drinking-water supplies. The same streams used for 

drinking water support recreational activities and the 

tourism-based economies of many mountain communities. Local tourism depends heavily on water-related 

recreation, such as fishing and skiing (stream water is 

used in snow-making), which are dependent on water 

quality. 

Water-resource managers must be prepared to 

manage a near-stream hazardous spill because streamflow can quickly carry contaminants to downstream 

communities, where public water supplies could be 

affected. The ability to estimate accurately the downstream rate of travel of a hazardous material plume is 

essential to minimize the effects of spills on downstream water supplies. Protective actions, such as 

closing water-intake valves, may be required before a 

spill reaches a vulnerable downstream point. 

Gore Creek and its major tributary, Black Gore 

Creek, are vulnerable to such contamination because 

Interstate 70 closely parallels these two streams from 

the headwaters on Vail Pass, through the Vail Ski 

Resort, to the confluence with the Eagle River (fig. 1). 

Interstate 70 crosses Gore Creek and tributaries 

20 times in the Gore Creek watershed and can be a 

source of contaminants, such as sand, deicing salts, 

motor-oil, and chemical spills. Thus, because traveltime information was not available for Gore Creek and 

Black Gore Creek to assist water-resource managers in 

the event of a hazardous spill, the U.S. Geological 

Survey (USGS) conducted a traveltime study as a part 

of the Upper Colorado River Basin National WaterQuality Assessment study.

Purpose and Scope

The purpose of this report is to present traveltime and longitudinal-dispersion characteristics for 

11 stream reaches in Black Gore Creek and Gore 

Creek. The results of the traveltime measurements 

were used to estimate the traveltime of potential 

contaminant releases in Black Gore Creek and Gore 

Creek and to calculate longitudinal dispersion coefficients. During May and September 1997, traveltime 

measurements were conducted along Black Gore 

Creek and Gore Creek from a site just downstream 

from the Black Lakes to the confluence with the Eagle 

River (fig. 1) to account for seasonal variability in 

stream discharge. These measurements were 

conducted at 12 sites, over approximately 18.2 miles 

of stream (11.4 miles on Gore Creek and 6.8 miles on 

Black Gore Creek). Table 1 lists traveltime sites and 

their locations on Black Gore Creek and Gore Creek. 
INTRODUCTION 3

Figure 1. Location of study area and dye injection and sampling sites in the Gore Creek watershed.

Study area

Upper

Colorado

River Basin

Upper

Colorado

River Basin

Colorado

109 

108 

107 

40 

Colorado

River

Eagle River

Gunnison

River

39 

38 

106

Gore Creek

Watershed

Middle Creek

Pitkin Creek

Gore

Creek

Red

Sandstone Creek

Big Ho rn C reek

Polk

Creek

Mill Creek

Gore Creek

Black

Gore

Ra nge

Vail Ski Resort

Black 

Lakes

Vail Pass

Interstate 70

 EXPLANATION

Urban areas

Traveltime site

U.S. Geological Survey gaging station 

Dye injection and sampling site

Dye sampling site

0 1 2 3 4 5 MILES

0 1 2 3 4 5 KILOMETERS

9 10

11

12

12

7

6

3

2

5

1

4

8

8
4 Traveltime Characteristics of Gore Creek and Black Gore Creek, Upper Colorado River Basin, Colorado

Study Area

The Gore Creek watershed encompasses 

approximately 102 mi2

 in the Upper Colorado River 

Basin, some of which has recently undergone significant urban development. The headwaters of Gore 

Creek originate in the Gore Range in the eastern part 

of the Gore Creek watershed. Gore Creek flows west 

to the confluence with the Eagle River. Land-surface 

elevation in the Gore Creek watershed ranges from 

13,300 ft in the Gore Range to 7,720 ft at the confluence with the Eagle River. Hydrology of the watershed 

is highly variable because of steep-gradient topography and large seasonal variation in stream discharge. 

Seasonal variation in stream discharge results from 

accumulation of deep snowpack during winter and 

large runoff during spring and summer from melting 

of the snowpack. Stream morphology also is variable, 

with significant downstream changes in bed material, 

channel shape, and ponded features such as natural 

and manmade pools and dams. 

Water quality, biological health, and overall 

esthetic value of Gore Creek are of major concern to 

local residents. Gore Creek has been identified as 

having a healthy and diverse biological community. 

Due to an exceptional brown trout community, the 

Colorado Division of Wildlife has designated the 

lower 4-mile reach of Gore Creek a Gold Medal trout 

fishery. During the past few decades, sections of the 

Gore Creek watershed have been developed for recreation and tourism uses. The population in Eagle 

County has increased by 59 percent between 1990 

(21,928) and 1999 (34,950) (U.S. Bureau of the 

Census, 2000). Much of this growth has occurred near 

Gore Creek and its tributaries. 

Acknowledgments

The authors thank Bob Boulger, Nancy Driver, 

Jeff Foster, and Barbara Ruddy, USGS, for collection 

of dye samples. Acknowledgments also are extended 

to Mary A. Kidd for editorial review, Alene J. Brogan 

for manuscript and layout, and Sharon M. Clendening 

for graphic design. 

THEORY AND METHODS FOR 

DETERMINATION OF TRAVELTIME 

AND LONGITUDINAL-DISPERSION 

CHARACTERISTICS

Traveltime and longitudinal-dispersion characteristics of a stream vary with flow conditions. ThereTable 1. Traveltime sites on Black Gore Creek and Gore Creek, Colorado

[na, not applicable]

Site no. 

(fig. 1) Site name

U.S. Geological 

Survey

station number

Distance 

upstream from 

mouth of Gore 

Creek

(river miles)

Latitude Longitude

1 Black Gore Creek below Black Lake 393307106133200 18.24 39° 33'07" 106° 13'32"

2 Black Gore Creek at Polk Creek 393527106143500 14.81 39° 35'27" 106° 14'35"

3 Black Gore Creek near Minturn 09066000 13.78 39° 25'47" 106° 15'52"

4 Gore Creek at upper station, near Minturn 09065500 11.65 39° 37'33" 106° 16'39"

5 Gore Creek below Black Gore Creek 393737106165900 11.20 39° 37'37" 106° 16'59"

6 Bighorn Creek near Minturn 09066100 10.07 39° 38'24" 106° 17'34"

7 Gore Creek at Bighorn subdivision 393831106181900 9.47 39° 38'31" 106° 18'19"

8 Gore Creek at well field 393844106192100 8.36 39° 38'44" 106° 19'21"

9 Gore Creek at golf course entrance na 6.69 39° 38'32" 106° 21'07"

10 Gore Creek at lower station, at Vail 09066310 4.13 39° 38'28" 106° 23'37"

11 Gore Creek at West Vail exit 393738106251000 2.13 39° 37'38" 106° 25'10"

12 Gore Creek at mouth near Minturn 09066510 0.09 39° 36'37" 106o26'46"
THEORY AND METHODS FOR DETERMINATION OF TRAVELTIME AND LONGITUDINAL-DISPERSION CHARACTERISTICS 5 RHODAMINE WT CONCENTRATION, IN MICROGRAMS PER LITER

0

0 12 3 4 5 6

1

2

3

4

5

6

7

TRAVELTIME, IN HOURS

b

a c

Site A

Site B

Site C

Site D

Dye injected upstream 

from site A

c Trailing edge

b Peak concentration

a Leading edge

fore, traveltime and longitudinal-dispersion 

characteristics for a stream reach are determined by 

measuring the rate of movement and dispersion of a 

substance injected into a stream for a range of flow 

conditions. 

Tracer Theory

A conservative dye tracer, such as rhodamine 

WT, acts as a solute, completely mixing with the 

stream and simulating movement and dispersion of 

water particles. Monitoring the shape and speed of a 

resulting dye-tracer cloud determines movement and 

dispersion of dissolved elements within the stream. 

Therefore, characteristics of dye-tracer clouds, such as 

traveltime and longitudinal-dispersion coefficients, 

reveal the movement and dispersion of potential 

conservative contaminants that may enter a stream 

(Ruddy and Britton, 1989). 

Traveltime

Traveltime measurements are necessary to characterize movement of dissolved contaminants (solutes) 

that may enter a stream. For this study, traveltime is 

defined as elapsed time (in hours) for the travel of a 

solute from the point of injection to the next downstream sampling point. Cumulative traveltime is 

defined as traveltime from injection to any given 

downstream sampling point of interest. Traveltime 

measures elapsed time of travel for a given solute, 

whereas velocity of a solute measures the rate 

(distance per time) of travel. Stream velocity measures 

the rate of downstream travel of water particles in a 

given stream reach. Stream velocity is highly variable 

and is dependent on storage, channel shape, slope, 

morphology, and streambed materials. Ponded 

features, such as manmade or beaver dams, can significantly alter stream velocity. Solute traveltimes can be 

estimated by using stream velocity determined from 

discharge measurements, but this method often 

provides inaccurate results. To more accurately determine traveltime and account for inherent variability in 

stream velocity, dye-tracer techniques are used. 

The shape and speed of a typical dye-tracer 

cloud resulting from an instantaneous injection is 

shown in figure 2, which shows the leading edge, peak 

concentration, and trailing edge. The traveltime for the 

leading edge of a dye tracer is when the cloud first 

reaches a specific point on a stream and, according to 

Jobson (1996), is approximately 89 percent of the peak 

concentration traveltime. Traveltime of the peak 

Figure 2. Typical dye response curves (sites A to D) resulting from an instantaneous upstream injection 

of tracer.
6 Traveltime Characteristics of Gore Creek and Black Gore Creek, Upper Colorado River Basin, Colorado

concentration is when the highest concentration of the 

dye reaches a specific point on a stream. The difference between the traveltime of the trailing edge and 

the leading edge of the curve represents the time of 

passage at a specific point on a stream. Characteristics 

of a conservative dye curve can be applied to estimate 

the traveltime characteristics of other conservative 

solutes in that stream.

Longitudinal Dispersion

Longitudinal dispersion is the process whereby 

a mass of solute introduced into a flowing stream is 

mixed and diluted in the longitudinal, or downstream, 

direction (Nordin and Sabol, 1974). Immediately 

following a slug injection, a dye tracer simultaneously 

disperses in all three dimensions. Complete mixing in 

the vertical direction normally occurs first. Although 

dispersion of a solute typically depends on specific 

stream characteristics and velocity variations, 

complete lateral mixing typically occurs second. 

Dispersion in the longitudinal direction continues infinitely, as it has no boundaries. A typical dye curve as 

shown in figure 2, illustrates longitudinal-dispersion 

effects. As the dye travels downstream, a decrease in 

peak concentration occurs as the cloud spreads and 

disperses longitudinally along the stream reach. 

The longitudinal dispersion of a particular 

stream reach can be described by a longitudinaldispersion coefficient, Kx, with which the degree of 

dispersion can be estimated. Longitudinal-dispersion 

coefficients are independent of concentration and time, 

representing the rate of dilution of a soluble substance 

into a stream by means of mixing in an increasing 

volume of water as the dye cloud lengthens (Nordin 

and Sabol, 1974). Longitudinal-dispersion coefficients 

are estimated by the following equation:

Kx = (U 2

 / 2)d(σt

2

) / (dt) (1)

where

Kx = longitudinal-dispersion coefficient, in square 

feet per second;

U = mean peak velocity of dye cloud, in feet per 

second;

σt

2

 = variance of dye cloud concentration with 

respect to time, in seconds squared; and

dt = change in time, in seconds. 

Equation 1 is assumed to approximate the longitudinal-dispersion coefficient only after adequate 

mixing time is allowed. Immediately following injection, dispersion of the dye occurs at a faster rate than 

the stream velocity. Therefore, calculations for longitudinal-dispersion coefficients are only valid on stream 

reaches that have had adequate mixing time during 

which the dye tracer has uniformly mixed in the lateral 

direction (Fischer, 1973). 

Methods Used in the Gore Creek 

Watershed 

This traveltime study used a fluorometric dye 

injection and downstream dye detection by fluorometry to measure traveltime characteristics of Gore 

Creek and Black Gore Creek. Fluorometry is a widely 

accepted technique for stream traveltime measurements, as it provides simple and accurate stream-tracer 

detection at low concentrations of dye (Wilson and 

others, 1986). A slug of a fluorometric dye, rhodamine 

WT, was instantaneously injected at sites 1, 5, and 8 

during May 1997 and at sites 1, 4, and 8 during 

September 1997. Rhodamine WT is a conservative 

solute that is widely used in dye-tracing studies owing 

to a high detectability, good diffusivity, low sorptivity, 

and environmental safety (Wilson and others, 1986). 

However, the fluorescence of rhodamine WT is 

temperature dependent, resulting in slightly higher 

fluorescence readings at low water temperatures.

At sites downstream from dye-injection points, 

grab samples were collected from the approximate 

center of flow and fluorometry measurements were 

conducted using a Turner Designs Model 10 Fluorometer. Onsite fluorometry measurements aided in 

collecting samples at times that would distribute grab 

samples along the dye-curve profile. The onsite 

measurements were used to determine traveltimes of 

the leading edge and peak concentration of the dye 

cloud. To avoid temperature-dependent variations in 

fluorescence, a portion of each grab sample was 

analyzed at room temperature in the laboratory. More 

thorough descriptions of fluorometry, rhodamine WT, 

dye-tracer theory, and sampling techniques used 

during this study are presented by Wilson and others 

(1986) and Kilpatrick and Wilson (1989).

Average stream velocities between two sites 

were calculated by dividing the distance in river miles 

between sites by the traveltime of the peak dye 
TRAVELTIME 7

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

DISCHARGE, IN CUBIC FEET PER SECOND

Oct Nov Dec Jan Feb Mar Apr May June July Aug Sept

May 20-21 dye

injections

September 24-26 dye

injections

Gore Creek at mouth, near Minturn (site 12)

Black Gore Creek, near Minturn (site 3)

Gore Creek at upper station, near Minturn (site 4)

concentration between the two sites. Discharges for 

Gore Creek and Black Gore Creek were available from 

four USGS streamflow-gaging stations. These gages 

(table 1) are site 3, Black Gore Creek near Minturn 

(09066000); site 4, Gore Creek at upper station, near 

Minturn (09065500); site 10, Gore Creek at lower 

station, at Vail (09066310) (discontinued); and site 12, 

Gore Creek at mouth near Minturn (09066510). Index 

discharge values, required to develop linear-regression 

relationships for estimation of traveltimes, are defined 

as the representative discharge conditions for the 

period of time during the actual dye injections in Gore 

Creek and Black Gore Creek. The two gages used to 

develop index discharge values were sites 3 and 12. 

The variance of the dye cloud was calculated and used 

in estimating longitudinal-dispersion coefficients 

(eq. 1).

 TRAVELTIME

 Spatial and temporal variations in stream 

discharge are apparent by comparison of daily mean 

discharge at three gages along Gore Creek and Black 

Gore Creek (fig. 3). Downstream reaches in the watershed have higher discharge during the same time 

period than upstream reaches. Tributaries other than 

Black Gore Creek (fig. 1) contribute substantial 

streamflow to Gore Creek. Relatively higher discharge 

occurs throughout the basin during May and June and 

represents springtime snowmelt. 

Traveltime Measurements

Average velocity of the peak dye concentration 

during the May traveltime measurements ranged from 

1.20 mph at site 2 on Black Gore Creek to 3.5 mph at 

site 12 on Gore Creek (table 2), whereas during the 

September traveltime measurements, average velocity 

of the peak dye concentration ranged from 0.29 mph at 

sites 2 and 3 on Black Gore Creek to 1.02 mph at site 

12 on Gore Creek (table 3). Although dependent upon 

discharge and the distance between sites, high average 

velocities of peak dye concentration typically translated into short traveltimes. During the May traveltime 

measurements, discharges ranged from 82 ft3

/s at 

Black Gore Creek near Minturn to 724 ft3/s at Gore 

Creek at mouth near Minturn (table 2), whereas during 

the September traveltime measurements, discharges 

ranged from 3.6 ft3/s at Black Gore Creek near 

Minturn to 62 ft3

/s at Gore Creek at mouth near 

Minturn (table 3). Cumulative traveltimes for the peak 

Figure 3. Daily mean discharge for Black Gore Creek and Gore Creek during water year 1997.
8 Traveltime Characteristics of Gore Creek and Black Gore Creek, Upper Colorado River Basin, Colorado

dye concentration during the May traveltime measurements ranged from 3.45 hours (site 1 to site 3) in Black 

Gore Creek to 2.50 hours (site 8 to site 12) in Gore 

Creek (table 2), whereas cumulative traveltimes for the 

peak dye concentration during the September traveltime measurements ranged from 15.33 hours (site 1 to 

site 3) in Black Gore Creek to 8.65 hours (site 8 to site 

12) in Gore Creek (table 3). Cumulative traveltime of 

the centroid, which is the center of mass of the dye 

injection, closely approximated the cumulative traveltime of the peak dye concentration (tables 2 and 3). 

Beaver dams, which may seasonally change in 

size and location, act as major storage basins for 

solutes and potential contaminants. During the 

September dye injections, beaver dams on Black Gore 

Creek between site 1 and the confluence with Gore 

Creek substantially delayed movement of the 

rhodamine WT. For example, traveltime of the peak 

dye concentration from site 1 to site 3 (4.46 river 

miles) was 3.45 hours in May and 15.33 hours in 

September (fig. 4), due in part to the delays caused by 

the beaver dams and lower discharge in September 

than in May. Because of these obstructions on Black 

Gore Creek, the second rhodamine WT injection 

during September was injected at site 4, Gore Creek 

gage at upper station, near Minturn. Due to the change 

in dye-injection location, traveltime measurements 

were not made during the September low-flow conditions from site 3 on Black Gore Creek to the confluence with Gore Creek. However, an estimate of 

traveltime was calculated for the stream reach from 

site 3 to site 5 of Black Gore Creek, and the estimate is 

discussed in the “Estimated Traveltimes” section. 

Estimated Traveltimes

The primary goal of a traveltime study is to 

provide methods to estimate traveltime for a broad 

range of discharges. Traveltime data presented in 

tables 2 and 3 have a limited use because only 

Table 2. Traveltime data for the May 20 and 21, 1997, dye injections

[--, no data; mph, miles per hour; mL, milliliters; Q, discharge; ft3/s, cubic feet per second]

Site no.

(table 1

and

fig. 1)

Distance from 

injection point 

(river miles)

Cumulative traveltime of dye cloud

(hours)

Average velocity 

of peak between 

adjacent sites

(mph)

Variance of dye cloud 

between adjacent 

sites

 (hour, squared)

Leading 

edge Peak Trailing 

edge Centroid

Injection of 100 mL of 20-percent solution rhodamine WT at site 1 at 10:02 a.m. May 21, 1997

(Black Gore Creek near Minturn, site 3, Q = 82 ft3

/s)

1 -- -- -- -- -- -- --

2 3.43 2.45 2.85 3.75 2.96 1.20 0.04

3 4.46 3.03 3.45 4.50 3.52 1.72 0.05

5 7.04 4.18 4.63 6.07 4.79 2.19 0.09

6 8.17 4.53 5.00 6.38 5.15 3.05 0.09

Injection of 100 mL of 20-percent solution rhodamine WT at site 5 at 14:50 p.m. May 20, 1997

(Gore Creek at lower station at Vail, site 10, Q = 532 ft3/s) 

5 -- -- -- -- -- -- -

6 1.13 0.25 0.33 0.57 0.37 3.42 0.002

7 1.73 0.47 0.60 0.88 0.61 2.22 0.004

8 2.84 0.77 1.02 1.60 1.04 2.64 0.01

9 4.51 1.30 1.52 2.17 1.58 3.34 0.02

Injection of 300 mL of 20-percent solution rhodamine WT at site 8 at 10:50 a.m. May 20, 1997

(Gore Creek at mouth near Minturn, site 12, Q = 724 ft3/s)

8 -- -- -- -- -- -- --

9 1.67 0.38 0.48 0.77 0.51 3.48 0.004

10 4.23 1.12 1.28 1.85 1.36 3.20 0.01

11 6.23 1.68 1.92 2.52 1.96 3.13 0.02

12 8.27 2.20 2.50 3.20 2.55 3.50 0.03
TRAVELTIME 9

RHODAMINE WT CONCENTRATION,

 IN MICROGRAMS PER LITER

0

0 5 10 15 20 25

2

4

6

8

10

12

14

TRAVELTIME, IN HOURS

Site 2

site 3 (peak traveltime, 

 15.33 hours)

Site 2

Site 3 (peak traveltime, 

 3.45 hours)

Site 5

Site 6

May 21, 1997

Dye Injection

(sites 2-6)

September 25, 1997

Dye Injection

(sites 2-3)

Figure 4. Dye response curves, May 21 and September 25, 1997.

Table 3. Traveltime data for the September 24–26, 1997, dye injections

[--, no data; mph, miles per hour; mL, milliliters; Q, discharge; ft3/s, cubic feet per second]

Site no. 

(table 1

and

fig. 1)

Distance from 

injection point

(river miles)

Cumulative traveltime of dye cloud

(hours)

Average velocity 

of peak between 

adjacent sites

(mph)

Variance of dye cloud 

between adjacent 

sites

(hour, squared)

Leading 

edge Peak Trailing edge Centroid

Injection of 80 mL of 20-percent solution rhodamine WT at site 1 at 05:25 a.m. September 25, 1997

(Black Gore near Minturn, site 3, Q = 3.6 ft3/s)

1 -- -- -- -- -- -- --

2 3.43 10.08 11.83 20.50 12.91 0.29 3.07

3 4.46 13.50 15.33 22.50 16.20 0.29 3.19

Injection of 80 mL of 20-percent solution rhodamine WT at site 4 at 07:25 a.m. September 26, 1997

(Gore Creek at lower station at Vail, site 10, Q = 44 ft3/s)

4 -- -- -- -- -- -- --

5 0.45 0.32 0.50 0.83 0.52 0.90 0.01

6 1.58 1.50 1.90 2.95 1.99 0.81 0.05

7 2.18 2.35 2.85 4.10 2.96 0.63 0.07

8 3.29 3.80 4.42 6.85 4.70 0.71 0.33

9 4.96 5.65 6.55 9.64 6.86 0.78 0.49

Injection of 100 mL of 20-percent solution rhodamine WT at site 8 at 07:50 a.m. September 24, 1997

(Gore Creek at mouth near Minturn, site 12, Q = 62 ft3

/s)

8 -- -- -- -- -- -- --

9 1.67 1.25 1.79 3.05 1.93 0.93 0.07

10 4.23 3.83 4.67 6.70 4.84 0.88 0.20

11 6.23 5.67 6.65 9.25 6.85 1.01 0.28

12 8.27 7.67 8.65 11.25 8.84 1.02 0.31
10 Traveltime Characteristics of Gore Creek and Black Gore Creek, Upper Colorado River Basin, Colorado

discharge conditions measured during the traveltime 

measurements are represented. Water-resource 

managers could benefit from estimated traveltimes for 

a range of discharges in Gore Creek and Black Gore 

Creek. 

Estimated traveltimes for peak concentration of 

rhodamine WT dye were calculated for discharges 

ranging from 20 to 800 ft3/s for selected stream 

reaches. Estimated traveltimes were developed using 

relations established from linear-regression methods 

by relating measured peak traveltime to discharge 

from sites 3 and 12. Resulting estimated peak traveltimes for Black Gore Creek (sites 1 to 5) ranged from 

5.4 to 0.4 hour for discharges of 20 to 200 ft3/s 

(table 4) and for Gore Creek (sites 5 to 12), 5.5 to 

0.3 hour for discharges of 20 to 800 ft3/s (table 5). The 

discharge ranges of 20 to 200 ft3

/s and 20 to 

800 ft3/s are representative of the index discharge of 

Black Gore Creek and Gore Creek during respective 

dye injection and traveltime measurements. Although 

most hydrologic conditions for Black Gore Creek and 

Gore Creek are included within these ranges, 

discharge during peak spring runoff can be greater 

(fig. 3). Estimated traveltimes are not provided in 

tables 4 and 5 for discharge conditions representative 

of spring runoff (discharge greater than 800 ft3

/s) 

because of limitations in extrapolating beyond the 

range of measured values. 

Traveltime measurements were not conducted 

between site 3 and site 5 on Black Gore Creek during 

September because of the presence of beaver dams. In 

developing estimated traveltimes for this reach (site 3 

to site 5), the average velocity of the peak concentration between the two sites was assumed to equal that 

between site 5 and site 6 during the September traveltime measurements. This assumed average velocity of 

the peak concentration was divided by the actual 

distance (river miles) between site 3 and site 5 to estimate a measured traveltime, which was then used in 

the linear-regression method to develop estimated 

traveltimes between sites 3 and 5 (table 4). The 

assumption that the average velocity of the peak 

concentration between sites 3 and 5 was equal to that 

between sites 5 and 6 results in conservative traveltime 

estimates for use when predicting the rate of downstream travel of a potential contaminant plume originating in upstream reaches of Black Gore Creek.

The estimated traveltimes of the peak dye 

concentrations (tables 4 and 5) will provide waterresource managers with the necessary information to 

best approximate the rate of travel of hazardous spills. 

In the event of a spill, a stepwise procedure has been 

developed for water-resource managers to calculate 

estimated traveltimes of the leading edge and peak 

concentration of that spill. In developing this procedure, the contaminant was assumed to be conservative 

and the rate of spill was instantaneous. During the 

downstream transport of an actual spill, losses of the 

contaminant could occur by adsorption onto the 

streambed, volatilization, photochemical decay, and 

other chemical and physical processes.

Traveltime Estimation Example

Assume a tanker truck crashes and spills its 

cargo into Black Gore Creek, approximately 3 miles 

downstream from Black Lakes on Vail Pass (fig. 1). A 

surface-water diversion for irrigation is located near 

site 8 on Gore Creek. Operators of the water diversion 

want to know when to expect the leading edge and 

peak concentration of the contaminant plume at the 

diversion point so diverting contaminated water can be 

avoided. 

This example involves estimating the traveltime 

along Black Gore Creek from the spill to the mouth of 

Black Gore Creek and the traveltime along Gore Creek 

from the confluence of Black Gore Creek to the site of 

interest. The following steps can be used to determine 

the traveltime of the peak and leading edge of the 

contaminant.

Step 1. Using figure 1 and table 1, determine: (A) the 

location of the spill, (B) the closest study site upstream 

from the spill, and (C) the closest study site to the 

downstream point of interest.

A. Approximate location of spill: 3 miles downstream from Black Lake (from fig. 1)

B. Closest upstream study site from the spill: 

site 1, Black Gore Creek below Black Lake

(from fig. 1)

C. Closest study site to downstream point of 

interest: site 8, Gore Creek at well field

(from fig. 1)

Step 2. Determine traveltime for Black Gore Creek.

A. Determine discharge of Black Gore Creek at 

time of spill. 

Use site 3, Black Gore Creek near Minturn.

Real-time streamflow data can be obtained 

on the internet at the USGS Colorado 
TRAVELTIME 11

Table 4. Estimated traveltimes of peak dye concentration in Black Gore Creek and Gore Creek, Colorado[Discharge from Black Gore Creek near Minturn 09066000 (site 3); traveltime and cumulative traveltime in hours; shaded areas refer to “Traveltime Estimation Example”; --

second]

Site no.

(table 1

and

fig. 1)

Discharge, ft3/s

20 40 60 80 100 

Traveltime Cumulative traveltime Traveltime Cumulative traveltime Traveltime Cumulative traveltime Traveltime Cumulative traveltime Traveltime Cumulative traveltime 

1 -- -- -- -- -- -- -- -- -- -- 2 5.4 5.4 4.0 4.0 3.3 3.3 2.8 2.8 2.6 2.6 

3 1.3 6.7 0.9 4.9 0.7 4.0 0.6 3.4 0.5 3.1 5 1.3 8.0 1.3 6.2 1.2 5.2 1.2 4.6 1.1 4.2 

Table 5. Estimated traveltimes of peak dye concentration in Gore Creek, Colorado

[Discharge from Gore Creek at mouth near Minturn 09066510 (site 12); traveltime and cumulative traveltime in hours; shaded areas refer to “Traveltime Estimation Example”

second]

Site no. 

(table 1 

and

fig. 1)

 Discharge, ft3/s

20 40 60 80 100 

Traveltime Cumulative traveltime Traveltime Cumulative traveltime Traveltime Cumulative traveltime Traveltime Cumulative traveltime Traveltime Cumulative traveltime 

5 -- -- -- -- -- -- -- -- -- -- 

6 2.7 2.7 1.8 1.8 1.4 1.4 1.2 1.2 1.0 1.0 7 1.6 4.3 1.2 3.0 1.0 2.4 0.8 2.0 0.7 1.7 8 2.8 7.1 2.0 5.0 1.6 4.0 1.4 3.4 1.2 2.9 9 4.1 11.2 2.7 7.7 2.1 6.1 1.8 5.2 1.6 4.5 

10 5.5 16.7 3.7 11.4 3.0 9.1 2.5 7.7 2.3 6.8 11 3.5 20.2 2.5 13.9 2.0 11.1 1.7 9.4 1.6 8.4 12 3.7 23.9 2.5 16.4 2.0 13.1 1.7 11.1 1.5 9.9 

Site no. 

(table 1 

and

fig. 1)

 Discharge, ft3/s

300 400 500 600 700 

Traveltime Cumulative traveltime Traveltime Cumulative traveltime Traveltime Cumulative traveltime Traveltime Cumulative traveltime Traveltime Cumulative traveltime 

5 -- -- -- -- -- -- -- -- -- -- 6 0.6 0.6 0.5 0.5 0.4 0.4 0.4 0.4 0.3 0.3 

7 0.4 1.0 0.4 0.9 0.3 0.7 0.3 0.7 0.3 0.6 8 0.7 1.7 0.6 1.5 0.5 1.2 0.5 1.2 0.4 1.0 

9 0.8 2.5 0.7 2.2 0.6 1.8 0.5 1.7 0.5 1.5 

10 1.2 3.7 1.0 3.2 0.9 2.7 0.8 2.5 0.8 2.3 11 0.9 4.6 0.7 3.9 0.7 3.4 0.6 3.1 0.6 2.9 12 0.8 5.4 0.7 4.6 0.6 4.0 0.6 3.7 0.5 3.4 
12 Traveltime Characteristics of Gore Creek and Black Gore Creek, Upper Colorado River Basin, Colorado

NWIS-W Data Retrieval page: 

http://waterdata.usgs.gov/nwis-w/CO/. 

Discharge at Black Gore Creek near 

Minturn gage during time of 

spill = 92 ft3/s.

B. Estimate traveltime for Black Gore Creek.

Using table 4 and the discharge from step 2A, 

estimate the arrival time of the spill’s peak 

concentration at the mouth of Black Gore 

Creek (site 5). If the discharge is not found in 

table 4, interpolate between values that 

bracket the reported streamflow or use the 

higher streamflow value, which will provide a 

conservative traveltime (Vaill, 2000). Round 

92 ft3/s up to 100 ft3

/s for use in table 4. Traveltime from site 1 to 5 at 100 ft3

/s (from table 

4) is 4.2 hours (sum of traveltimes from sites 

1 to 2, 2 to 3, and 3 to 5).

The estimated traveltime of the peak in Black 

Gore Creek: 4.2 hours 

Step 3. Determine traveltime for Gore Creek.

Traveltime estimates for Gore Creek (table 5) 

are based on Gore Creek at mouth near 

Minturn (site 12).

A. Determine discharge of Gore Creek during the 

spill. 

Real-time streamflow data can be obtained 

on the internet at the USGS Colorado 

NWIS-W Data Retrieval page 

(http://waterdata.usgs.gov/nwis-w/CO/)

Discharge at Gore Creek at mouth near 

Minturn (site 12) during time of 

spill = 762 ft3/s.

B. Estimate traveltime for Gore Creek.

Using table 5 and the discharge from step 3A, 

estimate the arrival time of the spill’s peak 

concentration at the site of interest on Gore 

Creek (site 8). Round 762 ft3/s up to 800 ft3/s 

for use in table 5. Traveltime from site 5 to 

site 8 at 800 ft3/s (from table 5) is 1.0 hour 

(sum of traveltimes for sites 5 to 6, 6 to 7, and 

7 to 8).

The estimated traveltime of the peak in Gore 

Creek: 1.0 hour 

Step 4. Determine total traveltime.

Sum the traveltimes for Black Gore Creek 

(step 2B) and Gore Creek (step 3B).

Total traveltime = 4.2 + 1.0 = 

5.2 hours

Step 5. Estimate arrival time of leading edge.

The traveltime of the leading edge indicates 

when the contaminant will first reach a 

specific location. To determine the arrival of 

the leading edge of the contaminant, multiply 

the traveltime of the peak concentration 

(step 4) by 0.89 (Jobson, 1996).

Estimated traveltime of the leading edge: 

5.2 hours * 0.89 = 4.63 

hours

Longitudinal-Dispersion Coefficients 

 Longitudinal-dispersion coefficients were 

calculated for selected stream reaches and are representative of the discharge conditions during traveltime 

measurements (table 6). Selected stream reaches were 

chosen on the basis of adequate mixing time. Because 

the mixing time was not adequate, longitudinal-dispersion coefficients were not calculated for stream 

reaches between the injection site and the first downstream collection site. 

Longitudinal-dispersion coefficients ranged 

from 17.2 ft2/s at 4 ft3/s between sites 2 and 3 to 

650 ft2/s at 144 ft3/s between sites 7 and 8 (table 6). 

The longitudinal-dispersion coefficients presented in 

table 6 provide necessary variables for future streamcontaminant modeling in the Gore Creek watershed.
SUMMARY 13

SUMMARY

In the Rocky Mountains of Colorado, major 

highways are constructed in stream valleys. In the 

event of a vehicular accident involving hazardous 

materials, the close proximity of highways to the 

streams increases the risk of contaminants entering the 

streams. Recent population growth has contributed to 

increased traffic volume along Colorado highways and 

resulted in increased movement of hazardous materials, particularly along Interstate 70. Gore Creek and 

its major tributary, Black Gore Creek, are vulnerable 

to such contamination because Interstate 70 closely 

parallels the course of these two streams from the 

headwaters on Vail Pass to the confluence with the 

Eagle River.

 The primary goals of this traveltime study 

were to determine traveltime and longitudinaldispersion characteristics and to provide methods of 

traveltime estimation in Gore Creek and Black Gore 

Creek for a broad range of discharges. Traveltime 

measurements are necessary to characterize movement 

of contaminants that may enter a stream. This traveltime study used a fluorometric dye injection of 

rhodamine WT and downstream dye detection by fluorometry to measure traveltime characteristics of Gore 

Creek and Black Gore Creek. At sites downstream 

from the dye-injection point, grab samples were 

collected from the approximate center of flow and 

fluorometry measurements were made using a Turner 

Designs Model 10 Fluorometer. 

Average velocity of the peak dye concentration, 

during the May traveltime measurements, ranged from 

1.20 mph at site 2 on Black Gore Creek to 3.5 mph at 

site 12 on Gore Creek, whereas during the September 

traveltime measurements, average velocity of the peak 

dye concentration ranged from 0.29 mph at site 2 on 

Black Gore Creek to 1.02 mph at site 12 on Gore 

Creek. During the May traveltime measurements, 

discharges ranged from 82 ft3/s at Black Gore near 

Minturn to 724 ft3

/s at Gore Creek at Mouth near 

Minturn, whereas during the September traveltime 

measurements, discharges ranged from 3.6 ft3/s at 

Black Gore near Minturn to 62 ft3

/s at Gore Creek at 

Mouth near Minturn. Cumulative traveltimes for the 

peak dye concentration during the May traveltime 

measurements ranged from 3.45 hours (site 1 to site 3) 

in the Black Gore Creek to 2.50 hours (site 8 to 

Table 6. Longitudinal-dispersion coefficients (Kx) for selected stream reaches

 on Black Gore Creek and Gore Creek, Colorado 

[ft3/s, cubic feet per second; mph, mile per hour; ft2/s, square feet per second]

Stream reach, by 

site numbers in 

table 1 and fig. 1

Index 

discharge

(ft3/s)

Mean peak 

velocity of dye 

cloud

(mph)

Longitudinaldispersion

coefficients, Kx

(ft2/s)

2 to 3 4 0.34 17.2

2 to 3 89 2.02 346.5

3 to 5 144 2.03 537.9

5 to 6 11 0.53 24.8

5 to 6 144 2.72 234.7

6 to 7 11 0.77 55.6

6 to 7 144 3.13 293.7

7 to 8 11 0.64 231.8

7 to 8 144 2.58 650.0

8 to 9 11 0.77 172.4

8 to 9 144 3.09 260.6

 9 to 10 50 0.88 128.5

 9 to 10 590 3.01 380.3

10 to 11 50 1.00 159.6

10 to 11 590 3.33 459.2

11 to 12 50 1.03 63.2

11 to 12 590 3.46 484.5
14 Traveltime Characteristics of Gore Creek and Black Gore Creek, Upper Colorado River Basin, Colorado

site 12) in the Gore Creek, whereas cumulative traveltimes for the peak dye concentration during the 

September traveltime measurements ranged from 

15.33 hours (site 1 to site 3) in Black Gore Creek to 

8.65 hours (site 8 to site 12) in Gore Creek. During the 

September dye injections, beaver dams on Black Gore 

Creek, between site 1 and the confluence with Gore 

Creek, substantially delayed movement of the 

rhodamine WT. 

Estimated traveltimes for peak concentration of 

rhodamine WT dye were calculated for discharges 

ranging from 20 to 800 ft3

/s for selected stream 

reaches. Estimated traveltimes were developed by 

using relationships established from linear-regression 

methods by relating measured peak traveltime to 

discharge obtained from two USGS gaging stations 

[Black Gore near Minturn (09066000) and Gore Creek 

at mouth near Minturn (09066510)] during those 

measurements. Resulting estimated peak traveltimes 

for Black Gore Creek (sites 1 to 5) ranged from 5.4 to 

0.4 hour for 20 to 200 ft3/s and for Gore Creek (sites 5 

to 12), 5.5 to 0.3 hour for 20 to 800 ft3/s. 

In the event of a spill into Gore Creek or Black 

Gore Creek, a stepwise procedure has been developed 

for water-resource managers to estimate traveltimes of 

the leading edge and peak concentration of that spill. 

An example calculating estimated traveltimes for a 

hypothetical contaminant release in Black Gore Creek 

is presented in the report.

 Longitudinal-dispersion coefficients were 

calculated for selected stream reaches and are most 

representative of the discharge conditions during 

traveltime measurements. Longitudinal-dispersion 

coefficients ranged from 17.2 ft2

/s at 4 ft3/s between 

sites 2 and 3 to 650 ft2/s at 144 ft3/s between sites 7 

and 8. The coefficients are necessary variables for 

future stream-contaminant modeling in the Gore 

Creek watershed. 

REFERENCES CITED

Fischer, H.B., 1973, Longitudinal dispersion and turbulent 

mixing in open-channel flow, in Annual review of fluid 

mechanics: Palo Alto, Calif., Annual Review, Inc., 

v. 5, p. 59–78.

Jobson, H.E., 1996, Prediction of traveltime and longitudinal dispersion in rivers and streams: U.S. Geological 

Survey Water-Resources Investigations Report 96–

4013, 69 p. 

Kilpatrick, F.A., and Wilson, J.F., Jr., 1989, Measurement of 

time of travel in streams by dye tracing: U.S. Geological Survey Techniques of Water-Resources Investigations, book 3, chap. A9, 27 p.

Nordin, C.F., and Sabol, G.V., 1974, Empirical data on 

longitudinal dispersion in rivers: U.S. Geological 

Survey Water-Resources Investigations Report 20–74, 

332 p.

Ruddy, B.C., and Britton, L.J., 1989, Traveltime and reaeration of selected streams in the North Platte and Yampa 

River basins, Colorado: U.S. Geological Survey WaterResources Investigations Report 88–4205, 56 p.

U.S. Bureau of the Census, 2000, County population estimates for July 1, 1999, and population change for 

April 1, 1990, to July 1, 1999, for Colorado: [U.S. 

Bureau of the Census Web pages] accessed April 4, 

2001, from URL http://www.census.gov/population/estimates/county/co-99-2/99C2_08.txt. 

Vaill, J.E., 2000, Traveltime and dispersion of contaminants 

in the Yampa River from Steamboat Springs to the 

Green River, northwestern Colorado: U.S. Geological 

Survey Water-Resources Investigations Report 99–

4239, 8 p.

Wilson, J.F., Jr., Cobb, E.D., and Kilpatrick, F.A., 1986, 

Fluorometric procedures for dye tracing: U.S. Geological Survey Techniques of Water-Resources Investigations, book 3, chap. A12, 34 p.