FLOOD01774

• County: Otero
• Community: La Junta
• Title: Analysis of Hydrologic Factors that Affect Grond-Water Levels in the Arkansas River Alluvial Aquifer near La Junta Colorado 1959-99
• Date: 1/1/2000
• Prepared For: La Junta
• Prepared By: USGS
• Floodplain - Doc Type: Educational/Technical/Reference Information

CONTENTS

Abstract ...................................... .............................................................................................................................. .......... I
Introduction........................ ............................ ................................................. ................... ...................... ......................... I
Previous Investigations ................ ... ................. ...................................... .. ................. . ................. ... ................... ... .... 3
Acknowledgments ........ ............................................................................ ................ .................. ............................. 3
Water-Table Conditions in March 1999............................................. ................................................. .................... 3

Water-Table Map................... .................................................... ................................................ .................. ............. 7
Estimate of Ground-Water Storage ........... .................... ................ ............. ... ....................................................... ....... 7
Depth to Water............................................... ............................................................................................................. 7
Historical Water Levels ................................................ ............ ..................................................................................... ....... 7
General Changes in Water Levels....... ............... ........................................................................................................ 9

Regression Characterization................... ............. ............................................................................. ................ 14
Fluctuations in Water Levels.................................................... ........................................................................... IS
Short-Tenn Variation in Water Levels ....... ................................................................................................................. IS
Hydrologic Factors That Affect Ground.Water Levels ......................................................................................................... 15

Surface-Water Conveyances ............... ........... .................... ......................... . ............................. ................. ........ ....... 16
Surface-Water A ppl ications .............................................. .............................. ............................................................. 19
Ground-Water Withdrawals.... ......................................................................... ........................................................... 21
Channel Processes ............................................... ...................................................................................................... 21
Interrelations of Ground-Water Levels and Affecting Factors ............................. ...................................................... 22

Summary.............................................................................. .................................................................................................. 24
References Cited............. ...................... ................ ............. ................................ .............................. .................................... 25

FIGURES
1-3. Maps showing:
1. Location of study area and selected wells ... ............................... .............................. ...................................... 2
2. Generalized water-table contours derived from measurements made March 9 through March 19. 1999......... 6
3. Generalized depth-to-water calculated from measured water table and digital representation

of land-surface elevations ..... .............. .............................. . ............................. .............................. ................. 8
4-6. Hydrographs showing:

4. General trends in ground-water levels............................................................................................................... 14
5. Mean daily and annual total flow in the Fort Lyon Canal ................................................................................. l7
6. Mean daily and annual total flow in the Arkansas River at La Junta ....................................... ........................ 20
7. Comparison of annual-total, daily mean. and instantaneous time-series data for hydrologic

factors in the study area................................. .................................................................................................... 23

TABLES

I. Description of wells used to measure water table, March 9 through March 19, 1999............................................ 4
2. Frequency analysis for calculated depths to water.................................................................................................. 9
3. Summary for Ground Water Site Inventory wells with multiple measurements in and near the study area........... 10
4. Annual values for hydrologic records in the study area.................................................................................. 18
5. Flow-duration statistics for the Fort Lyon Canal and the Arkansas River at La Junta............................................ 19

CONTEIHS III