WSP09693

• File Number: 8220.106
• Description: Animas-La Plata
• State: CO
• Basin: San Juan/Dolores
• Water Division: 7
• Date: 7/1/2000
• Title: Final Supplemental Environmental Impact Statement - Volume 1
• Water Supply Pro - Doc Type: EIS

TABLE OF CONTENTS (continued)

Chapter

Pal!e No.

3 AFFECTED ENVIRONMENT AND ENVIRONMENTAL CONSEQUENCES ....... 3-1

3.1 INTRODUCTION. .. . , . . .. . . , . . , . . . . . . . , .. . . . . . , . . . . . . . . . . . . .. . .. . . . . . 3-1
3.1.1 Structural Components ... . . . . . . . . . . . .. . . . . , , . . . . . . . . .. . . . . . . . . . .. 3-1
3.1.2 Non-Structural Component ......................................,.3-2
3.1.3 Non-Binding End Uses. . . . . . . . . . .. . . . , . . . . . . . . . . .. . . . . . . , .. . . . . . . 3-2
3.1.4 Structure of Sections.. .. . . . . . . . . . . . . .. . . . . . . . . .. , . . . . . . .. . . , . . . . . 3-3
3.2 WATERRESOURCESfHYDROLOGY.......,.......................,.... 3-4

3.2.1 Introduction. . , . . . , . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . 3-4
3.2.2 Evaluation Methodology. . . , . . . . , , . . , . . . . . . . . . . . . . . . . , . . . . . . . . . . . . 3-4
3.2.2. I Methodology .. . . . . . . . . . . . . .. , . , . . . .. . . . . . . . . . . . . . , . . . . . 3-4
3.2.2.1.1 Configuration for Future Conditions Without the

Project ......................,.,......,.,., 3-5
3.2.2.1.2 Configuration for the Refined Alternative 4 ...... . 3-5
3.2.2.1.3 Configuration for Refined Alternative 6 . . . , . . . . . 3-12
3.2,2.2 Significance Criteria.. . . . . .. . . . . . .. , . . . . . . . . . . . . . . .. . . .. 3-14
3.2.3 Affected Environment. .. . . . . .. . . . , . .. . . . . . .. . . . . . . . . . . , .. . . . . . , . 3- I 7
3.2.3.1 Refmed Alternative 4 Structural Component.,. ...,..........3-17
3.2.3.1.1 Animas River .,..,.............,...........3-17
3.2.3.1.2 La Plata River .,............,..............3-18
3.2.3.1.3 Mancos River. . . . . . . . . . . . . . . . . . . . , . . , . . . . . . 3-18
3.2.3.1.4 San Juan River ....,.................,.....,3-18
3.2.3.1.5 Navajo Reservoir . .................... ......3-19
3,2.3.2 Refined Alternative 4 Non-Structural Component. . . . . . , . . . . . . 3-19
3.2.3.2.1 Pine River .....,.........................,3-19
3.2.3.2.2 Florida River. . . . . . . .. . . . . . . . . .. . . . .. . . . . . , 3-19
3.2.3.3 Refined Alternative 6 . . .. . . , , .. . , . .. . , . , . . , .. .. , . , . , . . . . 3-19
3.2.3.3.1 Dolores River. . , . . . . . . . . . . , . . . . . . . , . . . . . . . . 3-19
3.2.3.3.2 McElmo Creek. . .. .. . . . .. . . . . . . . . . .. . . .. . . . 3-20
3.2.4 Environmental Consequences and Mitigation .................,...... 3-20
3.2.4.1 Refmed Alternative 4 .... . . . . , . , . . . . . . . . . . . . . . . . . . . . . . . , 3-20
3.2.4. 1.1 Operation of Structural Components and Delivery
to Non-Binding Uses . . .. . . . . . .. . .. . . . , . . . , .. 3-20
3.2.4.1.2 Water Conveyance Impacts for Non-Binding Uses. 3-28
3.2.4.2 Refined Alternative 6 . . . .. . . . .. . .. , . . . . . . . . . . . .. . . . .. . . . 3-28
3.2.4.3 No Action Alternative ...........................,...... 3-33
3.3 WATER QUALITY ......,...,................,....................... 3-34
3.3.1 Introduction.. . . . . . .. . .. . .. . . . .. . . .. . . .. . .. . , . .. . . .. .. . . .. , . , .. 3-34
3.3.2 Evaluation Methodology .. . .. . . . . , .. . . , . .. .. . . . . . .. . .. . . . . .. , . . . . 3-34
3.3.2.1 Methodology. .. . .. . . . . . .. . .. . . . . . . . . . . .. . . .. . . . . , . . . . . 3-34
3.3.2.1.1 Approach. , . . . .. . .. . , . , .. . .. . .. .. . . . . .. . . . 3-34
3.3.2.1.2 Standards by State .... . . . .. . . . . . . .. . , . . .. .. . 3-35
3.3.2.1.3 Sites with Water Quality Measurements......... 3-37
3.3.2.1.4 Historic Streamflow Data ..,....,....,....... 3-37
3.3.2.1.5 Streamflow Data from the San Juan River
Hydrology Model. . , . , . . . . , . .. . . .. . . . . . . .. . . 3-37
3.3.2.2 Significance Criteria. .. . .. . .. , , . .. . . . , .. . . . , . . . . . . .. . . , . 3-39

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