WSP09785

• File Number: 8142.600.30.A
• Description: Trinidad Project - Studies - Other Studies - Purgatoire river transit loss study
• State: CO
• Basin: Arkansas
• Water Division: 2
• Date: 1/1/1993
• Author: USGS
• Title: Evaluation of Streamflow Traveltime and Streamflow Gains and Losses Along the Lower Purgatoire River Southeastern Colorado 1984-1992
• Water Supply Pro - Doc Type: Report/Study

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CONTENTS

Abstract........... .............. ...................... ................. .............. ....................... .................. .w................ .................... ........w........ I
Introduction...... ................... .................... ................... ............. .................... ...................... ................... ...................... ........... 2
Purpose and Scope........... .................. ............... ................. .w................ ...................... ...................... .......................... 2
Acknowledgments ............... ................... .............. ...................... .................. ...................... ....................... .................. 2
Description of the Study Area ..................................................................................................................................... 2
Previous Studies.............. .................. ............... .................. ................... .................. ...................... ...................... ........ 5
Generalized Study Approach ............... ................. ...................... .................. ................... ....w........... .......................... 6
Method of Data Presentation..... ................ .............. ...................... ................... ...................... .................. ................... 7
Streamflow Characteristics..... ................. ................... ................ ....w............. .................. .................... ...................... ........... 9
Streamflow Traveltimes ................ .... .............. ................ .................. .................. ......... ............. ................... .......................... 14
Reach I .. .................. .w............. ........,'....... ............... ..................... .................... ................... ......................... ............... 15
Reach 2 ......... ................... .............. ................... ................ ..................... .:w............ ................... ....................... ........... 15
Reach 3 ............. .................. ................... ................ ................. .................. .... ............... ...................... ..w..................... 15
Streamflow Gains and Losses ................. ................ ............ ..................... ................... .................. ................... ...................... 16
.
Reach I ............. ................. ................ ............... .............. ...................... ................... .................. ...................... ............ 17
Reach 2 .. ............. ................. ................... ................. ............... .................... .................... ................ ............................. 17
Reach 3 ..... ................... .............. ................... ............ ..................... .................. ....................... .................. ................... 19
Confidence in Accuracy of Estimates.......... .............. ................. .................... ................... .................. ...................... ............ 22
Summary......... ............... ............... ................. ............... ................ ..w................ ................... ....w............... ........................... 23
References Cited ................ .................. ............... ............... ..................... ................... ................... ..w................. .....w........... 24

FIGURES

I. Map showing locations of surface-water sites and river reaches used in the evaluation of streamflow
traveltime and streamflow gains and losses in the study area..................................................................................... 3
2. Graph showing mean monthly precipitation and mean monthly air temperature near Hoehne, 1947-92 ................. 5
3. Diagram showing explanation of information for a boxplot ...................................................................................... 9
4. Graph showing flow-duration curves for the streamflow-gaging stations, Purgatoire River below
Trinidad Reservoir (site QI) and Purgatoire River at Trinidad (site QIA) comparing two different
periods of streamflow entering the study area, 1957-67 and 1984-92...................................................................... 10
5. Boxplots showing daily mean streamflow for the streamflow-gaging stations (A) Purgatoire River at
Trinidad (site QIA), 1957-67; Purgatoire River below Trinidad Reservoir (site QI), 1984-92; and
(B) Purgatoire River near Las Animas (site Q4), 1957-67 and 1984-92................................................................... 11
6. Boxplots showing daily mean streamflow by season for the streamflow-gaging stations Purgatoire
River below Trinidad Reservoir (site Ql); Purgatoire River near Thatcher (site Q2); Purgatoire River
at Rock Crossing near Timpas (site Q3); and Purgatoire River near Las Animas (site Q4), 1984-92...................... 13
7-9. Graphs showing:
7. Relation of traveltime to instantaneous peak streamflow for two reaches ofthe study area, 1990-94............. 16
8. Example of (A) unadjusted hydrographs and (B) a traveltime-adjusted upstream hydrograph of daily

mean streamflow ................................................................................................................................................ 18
9. Example of selection of streamflow-event periods for analysis of daily streamflow gain and loss .................. 19
10. Boxplots showing daily mean streamflow gains and losses and daily mean streamflow-event gains and
losses for reach 2 of the study area, 1984-92 ......................................................................................................."'''' 20
II. Boxplots showing daily mean streamflow gains and losses and daily mean streamflow-event gains and
losses for reach 3 of the study area, 1984-92 .............................................................................w............................. 22

TABLES

1. Summary of river reaches, streamflow-gaging stations, river distances, drainage areas, and analysis
periods used at selected surface-water sites along the lower Purgatoire River....................................................... 8
2. Percentage of time daily streamflow occurred at selected tributary streams for the upper and middle
reaches of the study area, 1957-67 and 1984-92.................................................................................................... 14
3. Statistical summary of daily streamflow estimates of gains and losses and daily streamflow-event
gains and losses for the middle and lower reaches of the study area, 1984-92...................................................... 21

CONTENTS III