Operational and Water Quality Summary Report for Grand Lake and Shadow Mountain Reservoir 2010 Revision 1 Operational and Water Quality Summary Report for Grand Lake and Shadow Mountain Reservoir 2010 This report was prepared for: Grand County Northern Water U.S. Bureau of Reclamation by: Jean Marie Boyer, PhD., PE, Hydros Consulting Inc. Christine Hawley, M.S., Hydros Consulting Inc. We wish to thank members of the Three Lakes Nutrient Study Technical Committee and external reviewers for their thoughtful review of, and comments on, the draft of this report. Your comments led to valuable insights and helped to produce a more in-depth analysis. December 2, 2011 Revision 1: Replaced Figures 28 and 74 with corrected versions. Issued March 16, 2012 December 2, 2011 Page i Operational and Water Quality Summary Report for Grand Lake and Shadow Mountain Reservoir 2010 Table of Contents I. Introduction ........................................................................................ 1 A. Statement of Problem and Background Information ..................................................................... 1 B. Purpose and Scope of Report ............................................................................................................. 4 II. Three Lakes System Operations ...................................................... 5 III. Factors Impacting Water Clarity ...................................................... 7 IV. Data and Analysis ............................................................................ 10 A. Data Sources ....................................................................................................................................... 10 B. Conditions in Previous Years (2007-2009) .................................................................................... 11 1. Hydrology and C-BT Operations .................................................................................................... 11 2. Lake and Reservoir Water Clarity ................................................................................................ 19 3. Water Clarity During „Stop-Pump‟ Periods ................................................................................. 23 4. Nutrient Loading (2007-2009) ..................................................................................................... 27 5. Meteorology..................................................................................................................................... 33 6. Grand Lake Clarity Standard Assessment (2007-2009).......................................................... 44 C. Conditions in 2010 ............................................................................................................................. 46 1. Hydrology and C-BT Operations .................................................................................................... 46 2. Lake and Reservoir Water Clarity ................................................................................................ 54 3. Conditions at Connecting Channel .............................................................................................. 61 4. Nutrient Loading (2010) ................................................................................................................ 64 5. Meteorology..................................................................................................................................... 70 6. Grand Lake Clarity Standard Assessment (2010) .................................................................... 75 V. Lessons Learned and Recommendations .................................... 77 VI. References ....................................................................................... 80 Appendix A: Three Lakes Clarity Monitoring Program…….…..……….A-1 December 2, 2011 Page ii Operational and Water Quality Summary Report for Grand Lake and Shadow Mountain Reservoir 2010 List of Figures Figure 1. The Three Lakes System ................................................................................................................ 1 Figure 2. Major Watersheds that Contribute Water to the Three Lakes System ................................... 2 Figure 3. Historical Secchi-Depth Measurements for Grand Lake (Data are from various locations in the lake and do not include measurements taken with the use of a view scope.) ................................ 3 Figure 4. Breakdown of Light-Attenuating Constituents in Water ........................................................... 8 Figure 5. Tributary and Pumped Inflows into the Three Lakes System (2007-2009) Tributary Inflows: North Inlet, East Inlet, North Fork of the Colorado River, Stillwater Creek, Columbine Creek, Roaring Fork, and Arapaho Creek. Pumped Inflows: Windy Gap Pipeline and Willow Creek Pump Canal Note: Stop-pump periods are shaded. ............................................................................................. 12 Figure 6. Outflows from the Three Lakes System (2007-2009) Stop-pump periods are shaded. ... 13 Figure 7. Flow between the Three Water Bodies (2007-2009) (Stop-pump periods are shaded. When flow is negative, the direction of flow is reversed) ......................................................................... 13 Figure 8. Farr Pumping Plant Flows (Granby Pump Canal) –2007 ....................................................... 14 Figure 9. Farr Pumping Plant Flows (Granby Pump Canal) –2008 (Shaded box denotes stop-pump period.) .............................................................................................................................................................. 14 Figure 10. Farr Pumping Plant Flows (Granby Pump Canal) –2009 (Shaded box denotes stop-pump period.) .............................................................................................................................................................. 15 Figure 11. Surface Water Elevation for Granby Reservoir (2007-2009) ............................................... 15 Figure 12. Inflows into Grand Lake by Source (2007-2009) Total Average Inflow 316,469 AF/yr.. 18 Figure 13. Inflows into Shadow Mountain Reservoir by Source (2007-2009) Total Average Inflow 332,464 AF/yr ................................................................................................................................................. 18 Figure 14. Inflows into Granby Reservoir by Source (2007-2009) Total Average Inflow 300,325 AF/yr ................................................................................................................................................................. 19 Figure 15. Grand Lake Secchi-Depth Data (All Locations, View-Scope Data) – 2007-2009 ............. 21 Figure 16. Grand Lake Secchi-Depth Data (All Locations, Non- View-Scope Data) – 2007-2009 .... 21 Figure 17. Shadow Mountain Reservoir Secchi-Depth Data (All Locations, View-Scope Data) – 2007-2009 ....................................................................................................................................................... 22 Figure 18. Shadow Mountain Reservoir Secchi-Depth Data (All Locations, Non-View Scope Data) – 2007-2009 ....................................................................................................................................................... 22 Figure 19. Grand Lake Secchi-Depth Data During 2008 Stop-Pump Period (All Locations, View- Scope Data) Stop-pump period is shaded. Inflow and Farr Pumping are also indicated. ................. 24 Figure 20. Shadow Mountain Reservoir Secchi-Depth Data During 2008 Stop-Pump Period (All Locations, View-Scope Data) Stop-pump period is shaded. Inflows are also indicated. ................... 24 Figure 21. Grand Lake Secchi-Depth Data During 2009 Stop-Pump Period (All Locations, View- Scope Data) Stop-pump period is shaded. Inflow and Farr Pumping are also indicated. ................. 26 Figure 22. Shadow Mountain Reservoir Secchi-Depth Data During 2009 Stop-Pump Period (All, Locations, View-Scope Data) Stop-pump period is shaded. Inflows are also indicated. ................... 26 Figure 23. Average Annual Total Phosphorus Load into Grand Lake (2007-2009 Average, Total = 5,844 kg/yr) ..................................................................................................................................................... 29 Figure 24. Average Annual Total Phosphorus Load into Shadow Mountain Reservoir (2007-2009 Average, Total = 11,098 kg/yr) .................................................................................................................... 29 December 2, 2011 Page iii Operational and Water Quality Summary Report for Grand Lake and Shadow Mountain Reservoir 2010 Figure 25. Average Annual Total Phosphorus Load into Granby Reservoir (2007-2009 Average, Total = 16,035 kg/yr) ..................................................................................................................................... 30 Figure 26. Average Annual Total Nitrogen Load into Grand Lake (2007-2009 Average, Total = 123,435 kg/yr) ................................................................................................................................................ 32 Figure 27. Average Annual Total Nitrogen Load into Shadow Mountain Reservoir (2007-2009 Average, Total = 122,999 kg/yr) .................................................................................................................. 32 Figure 28. Average