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 Figures
Figure 1-1. alamosa River Watershed Overview ..............................................................................................................1-2
Figure 2 -1. average annual Precipitation in alamosa River Watershed ...................................................................... 2-2
Figure 2 -2. Land Ownership in the Alamosa River Watershed .................................................................................... .. 2-4
Figure 2 -3. alamosa River Segments and Subwatersheds ............................................................................................. .. 2-5
Figure 2-4. alamosa River Profile and Segments ........................................................................................................... .. 2-6
Figure 2 -5. alluvial Fan ....................................................................................................................................................... .. 2-9
Figure 2 -6. Preliminary Stream Classification .................................................................................................................. 2-11
Figure 2 -7. Rosgen Stream Classification Methodology ................................................................................................ 2-12
Figure 2 -8. Photo of Burnt Creek and Sediment Load .................................................................................................. 2-13
Figure 2 -9. Photo of Sediment Influences by the Backwater of Terrace Reservoir .................................................. 2-14
Figure 2 -10. Photo of Sediment Deposition in Terrace Reservoir .............................................................................. 2-14
Figure 2 -11. Rating Curve Above Terrace Reservoir ..................................................................................................... 2-15
Figure 2 -12. Rating Curve Below Terrace Reservoir ...................................................................................................... 2-16
Fi ure 2
g -13. Photo Above Irri ation Diversion hoto b Alan Miller
g (P Y ) ..................................................................... 2-17
Figure 2 -14. Photo Below Irrigation Diversion (photo by Alan Miller) ..................................................................... 2-17
Figure 2 -15. Photo Near Capulin at Straightened Channel Section (photo by Alan Miller) .................................... 2-18
Figure 2 -16.100-year Flood Boundary Upstream of Highway 371 ............................................................................ 2-20
Figure 2 -17. 100-year Flood Boundary Downstream of Highway 371 ...................................................................... 2-21
Figure 2 -18. alamosa Basin Stream Gage Locations ..................................................................................................... 2-23
Figure 2 -19. Mean Monthly Streamflow in Wightman Fork ......................................................................................... 2-25
Figure 2 -20. Mean Monthly Streamflow in Upper alamosa River .............................................................................. 2-25
Figure 2 -21. Historical Flow - Alamosa River Near Terrace Reservoir ..................................................................... 2-26
Figure 2 -22. Mean Monthly Flow for alamosa River near Terrace Reservoir ........................................................... 2-26
Figure 2 -23. Flow Duration Curve for Alamosa River (October 1981 to September 2002) ................................... 2-27
Figure 2 -24. Subwatersheds and Precipitation Isohyetals for Runoff Estimates ....................................................... 2-29
Figure 2 -25. Terrace Reservoir Historic Water Storage ................................................................................................. 2-30
Figure 2 -26. average Monthly Surface Area and Evaporation from Terrace Reservoir .......................................... 2-31
Figure 2 -27. alamosa River Flood Frequency Curve ..................................................................................................... 2-32
Figure 2 -28. Diversions compared with Streamflow ...................................................................................................... 2-35
Figure 2 -29. Average Water Usage for Irrigation Years 1992 to 2002 compared to Water Right .......................... 2-37
Figure 2 -30. Rio Grande Compact Delivery Requirements Verses Annual Index Flows ........................................ 2-38
Figure 2 -31. Rio Grande Basin in Colorado .................................................................................................................... 2-39
Figure 2 -32. Photo of Lookout Mountain in Stunner altered Area ............................................................................ 2-41
Figure 2 -33. Hydrothermally altered areas in alamosa River Watershed ................................................................. 2-41
Figure 2 -34. Photo of Summitville Site in 1980 Prior to SCMCI Operations ........................................................... 2-45
Figure 2 -35. Photo of Summitville Site in 1991 During Summitville Operations ..................................................... 2-45
Figure 2 -36. Summitville Drainage Areas and Seeps ...................................................................................................... 2-47
Figure 2 -37. Impacts of SDI release on downstream pH in July 1997 ....................................................................... 2-48
Figure 2 -38. Contaminant Point Sources alamosa River Watershed .......................................................................... 2-51
Figure 2 -39. Photo of Drainage from the Pass-Me-By Mine Portal .......................................................................... 2-52
Figure 2 -40. Photo of Drainage from the Miser Mine ................................................................................................... 2-52
Figure 2 -41. Aerial Photo of Lower Iron Creek ............................................................................................................. 2-54
Figure 2 -42. aerial Photo of alum Creek ........................................................................................................................ 2-54
Figure 2 -43. aerial Photo of Bitter Creek ........................................................................................................................ 2-55
Figure 2 -44. aerial Photo of Wightman Fork ................................................................................................................. 2-55
Figure 2 -45. aerial Photo of Upper Jasper Creek ........................................................................................................... 2-56
Figure 2 -46. Aerial Photo of Upper Burnt Creek ........................................................................................................... 2-56
Figure 2 -47. Photo of "Ferrosinter" Mound in Burnt Creek ........................................................................................ 2-57
Figure 2 -48. Photo of acidic Ecosystem in Burnt Creek .............................................................................................. 2-57
Figure 2 -49. Water pH in Response to Rainfall Event at USGS gages ....................................................................... 2-58
Figure 2 -50. Distribution of Compiled Water Quality Samples by Year and Month ............................................... 2-59
Alamosa River Watershed Restoration Master Plan and Environmental Assessment Page vii