WSP08083

• File Number: 8220.114.I
• Description: Dolores Participating Project
• State: CO
• Basin: San Juan/Dolores
• Water Division: 7
• Date: 1/1/1977
• Author: USGS
• Title: Field Screening of Water/Soil/Bottom Sediment and Biota Associated with Irrigation Drainage in the Dolores Project and Mancos River Basin - Southwestern Colorado - 1994
• Water Supply Pro - Doc Type: Report/Study

CONTENTS

Abstract..................................................................................................................................................................................1
Introduction...... ....... ....... ........ ......... ... ....... ....... ........ ............ ....... ............. .... ................. ....... ..... ..... ........ ......... .... .................. 2
Background........... ........ ......... ........ ....... ............... .... ............... ....... ..... ..... ....... .......... ....... .......... ..... .............. ... ............ 2
Purpose and Scope ..... ...................... ....... .......... ..... ........................ ..... ........................ ..... ........................... .......... ....... 4
Acknowledgments ........................................................................................................,........................,..................... 4
Description of Study Area... ..... ............ ............ ................. ..... ............................. ................. ..... ......................... .... .......... ..... 5
Dolores Project ............. ............ ............................... ............,......... ................. .......... ............ ....... ... ................. ............ 5
Mancos Project .......... ........ .... ........ .............. ..... ............ ..... ................. ....... ........................... ................. ... .... ............... 6
Fish and Wildlife Resources..... ....... ............... ....... ........................ ................. .................... ......... ..... ............ ..... ..... ..... 6
Sample Collection and Analysis................ ............ .................... ......... .......,......... ...................... ..... ................. ... .............. ..... 7
Water Samples ...... ............. .... ... ....... ............ .....,.... ..... ................... .......... ............ ....... ........ ......... .......... ....... ............... 7
Soil Samples .............. ..... .......... ....... ....... ...................... ..... ... .... ................. ... .................... .... .....,........... ............... ....... 7
Bottom-Sediment Samples ..........................................................................................................,............................... 9
Biota Samples ............ ..... ..... ..... ................... ..... ............ ..... ..... ................... ........................................., ................. ....... 9
Field-Screening Results..... ..... ......... ............... ......................................... .................... ....... .......... ....... ............ ....... ............... 10
Dove Creek Area of the Dolores Project ..................................................................................................................... 11

Water. ............ .............. ... .......... ................... ..... ................... ................. ........ ....... ..... ..... .... ................. ............... II
Soil and Bottom Sediment ..... .................... .... .....,............................ ...................... ............ .................... ............ 13
Biota,..................,................,................."..,..,.....................,.....................................,..............................,..........14
Streams.. ...................... ....... ............... ................................ .... ................. ..... .:... ....... ..... ................. ..... ..... 14
Ponds and Wetlands.................................. ................. .......... .......... .........,......... ................. ..... .......... ....... 14
Montezuma Valley Irrigation Company Area of the Dolores Project...............................................................;......... 17

Water.......... ................. ........................................................ ...................... ... ............ .............. ..... ..... .......... ....... J 7
Biota....... ......................... ....... ....... .......... ....... .................................. .......... ........................ ........ ............ ............ 18
Mancos River Basin.................... ............ ....................................... ........ ......... ........ ............ ......... ..... .......... .......... ....... J 8
Water ...... ................. ......... ..... ............ ... .............. ........ .... .......... ....... ...................... ............ .......... ....... ............... 18
Soil and Bottom Sediment................................................................................................................................. 18
Biota....... ................................ ....... ............. ....... .......... ......... ............ ................. .......... ....... ..... ................. ..... ..... 19
Streams.. ............ ..... ... .............. ............ ..... ..... ............... ..... ............ ..... ......... .......... ....... .......... ............ ..... 19
Ponds and Wetlands... ................. ......... ............. ..................... ....................... ..... ...... .................... ............ 19
Summary ............................................................................................................................................................,................... 21
References Cited.... .... ............. ..... .............. ....... ............. ....... .......... ..................... .......... ....... ..... ..... ....... .................... ............ 22
Supplemental Data............... ..... ..... ............ ............... ......... .......... .......... ..... ......... ..... ........ ....... ....... ... ................... .......... ....... 25

FIGURES

I. Map showing locations of study area and sampling sites........................................................................................... 3
2~. Graphs showing:
2. Selenium concentrations in water samples from streams in the Dove Creek area, April and July 1994........... 12
3. Selenium concentrations in water samples from four streams in the Dove Creek area, J 990 and 1994........... 13
4. Geometric mean selenium concentrations in biota samples collected from streams in the Dove Creek

area, April and July 1994 ................................................................................................................................... IS
5. Geometric mean selenium concentrations in selected biota samples collected from ponds in the Dove

Creek area, June 1994 ...........................................,............................................................................................ 16
6, Selenium concentrations in water samples from streams in the Mancos River Basin, March and

July 1994.................. ........................................... ........ ....... .............. ........... ........................................ ..... ... ....... 19
7. Geometric mean selenium concentrations in selected biota samples collected from streams in the
Mancos River Basin, March and July 1994 ....................................................................................................... 20

CONTENTS III