Alamosa River Watershed Plan

• Document ID: 0001
• County: Rio Grande
• County: Conejos
• County: Costilla
• County: Saguache
• Stream Name: Alamosa River
• Basin: Rio Grande
• Sub-Basin: Alamosa-Trinchera 13010002
• Water Division: 3
• Title: Alamosa River Watershed Restoration Master Plan and Environmental Assessment
• Date: 7/1/2005
• Prepared For: CWCB
• Prepared By: MWH
• Watershed Pro - Doc Type: Planning Report

List of Tables
Table 2 -1. Alamosa River Segment and Subwatershed Characteristics .........................................................................2-3
Table 2 -2. Wightman Fork Alamosa River Segment and Subwatershed Characteristics ........................................... 2-7
Table 2 -3. Comparison of CDPHE and Master Plan Segments for the Alamosa River ............................................ 2-7
Table 2 -4. Alamosa River Channel Geometry Data .......................................................................................................2-10
Table 2 -5. Alamosa Basin Stream Gage Information .................................................................................................... 2-24
Table 2 -6. Tributary Average Flow Estimates ................................................................................................................. 2-28
Table 2 -7. Alamosa River Flood Frequency Data .......................................................................................................... 2-32
Table 2 -8. Senior dater Rights in the Alamosa Watershed .......................................................................................... 2-33
Table 2 -9. USFS appropriated Flows on Alamosa River for Rio Grande National Forest (cfs) ........................... 2-34
Table 2 -10. Priority Numbers Expected to be Fulfilled in a Given Month ............................................................... 2-34
Table 2 -11. Summary of Water Rights abandonments Since April 1997 ..................................................................2-35
Table 2 -12. Untreated Releases from Summitville Site ..................................................................................................2-48
Table 2 -13. Water Quality and Contaminant Loads from Mine Sites and Major Natural Springs .........................2-50
Table 2 -14. Summary of Critical Water Quality Standards for Alamosa River ..........................................................2-62
Table 2 -15. Water Quality Estimates for Period Before Mining and SCMCI Activities .......................................... 2-65
Table 2 -16. Comparison ofPre-Summitville, Summitville, and Post-Remediation Water Quality ...................... 2-75
Table 2 -17. Current Water Quality Conditions and Instream Standards by WQCC Segment ............................... 2-79
Table 2 -18. approximate annual Loads from Contaminant Sources .........................................................................2-89
Table 2 -19. Loads of Metals in 1997 in Alamosa River Reaches .................................................................................2-90
Table 2 -20. approximate Current Annual Contaminant Loads in Alamosa River ...................................................2-91
Table 2 -21. Selected Wells in the Alamosa River Watershed ........................................................................................2-99
Table 2 -22. Selected RGDSS Wells in the Vicinity of Capulin, Colorado ................................................................ 2-101
Table 2 -23. Summary of Terrace Reservoir Valve Repairs ......................................................................................... 2-112
Table 2 -24. Water Quality in Terrace Reservoir Following SCMCI activities ........................................................ 2-115
Table 2 -25. annual Metal Loads in Terrace Reservoir; 1994-1995,1997, and 1998-2003 ................................... 2-118
Table 2 -26. Chemical Composition of Terrace Reservoir Sediment Samples ......................................................... 2-119
Table 2 -27. Alamosa River Sediment Quality Data ...................................................................................................... 2-129
Table 2 -28. acreages Irrigated by Alamosa River by Crop ......................................................................................... 2-154
Table 2 -29. Water Ri hts Avera e Ditch Diversions and Water Sufficienc
g ~ g Y .......................................................... 2-157
Table 2 -30. Stream Segment and Subwatershed Evaluation Criteria ......................................................................... 2-171
Table 2 -31. Stream Segment and Subwatershed Rating ............................................................................................... 2-171
Table 3 -1. Segments Most Impacted by Human activities ............................................................................................. 3-3
Table 3 -2. Universe of All Potential Improvement Projects Upstream of Terrace Reservoir ................................ .. 3-5
Table 3 -3. Universe of All Potential Improvement Projects in Terrace Reservoir Subwatershed ......................... .. 3-6
Table 3 -4. Universe of All Potential Improvement Projects Downstream of Terrace Reservoir ........................... .. 3-7
Table 3 -5. Universe of rill Potential Improvement Projects Covering the Entire Watershed ................................ .. 3-8
Table 3 -6. Projects Eliminated in Initial Screening ........................................................................................................ .. 3-8
Table 3 -7. Summary of Project Evaluation Criteria ....................................................................................................... .. 3-9
Table 3 -8. Pros and Cons of Stabilizing Banks ............................................................................................................... 3-14
Table 3 -9. Pros and Cons of Dead Tree Management .................................................................................................. 3-15
Table 3 -10. Pros and Cons of Modifying Land Use Regulations ................................................................................. 3-15
Table 3 -11. Pros and Cons of Setback Levees ................................................................................................................ 3-16
Table 3 -12. Water Quantity Project Types and Specific Project Examples ............................................................... 3-16
Table 3 -13. Pros and Cons of Purchasing Appropriate Priority Water Rights .......................................................... 3-18
Table 3 -14. Pros and Cons of Filing a New Junior Water Right .................................................................................. 3-18
Table 3 -15. Pros and Cons of Controlled Releases from Terrace Reservoir with Ground Water Backup........... 3-19
Table 3 -16. Pros and Cons of Trade of Direct Flow Diversion Right for Reservoir Storage ................................. 3-21
Table 3 -17. Potential Reservoir Sites ................................................................................................................................ 3-22
Table 3 -18. Pros and Cons of Building New Reservoirs ............................................................................................... 3-22
Table 3 -19. Pros and Cons of Aquifer Storage ............................................................................................................... 3-25
Table 3 -20. Terrace Reservoir Spillway Rehabilitation Alternatives ............................................................................ 3-26
Alamosa River Watershed Restoration Master Plan and Environmental Assessment Page x