Overview of Water Resource Issues in the Carson River Watershed

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OVERVIEW OF WATER RESOURCE ISSUES IN THE CARSON RIVER WATERSHED

EDWIN JAMES, P.E. CWSD GENERAL MANAGER 2016 Carson River Watershed • ~ 3,966 square miles • Carson River - 184 miles • Population: Current: 156,000 Predicted: > 300,000 by 2040 • Limited Upstream Storage CWSD History

• CWSD Established by the Court to Negotiate payback of debt on the Watasheamu Dam between the ranchers and Federal Government 1959 • Douglas County and Lyon County join

• Federal Government abandoned Dam Project 1980s

• Nevada Legislator’s changed CWSD’s purpose 1989 • 1989 Carson City Joins

• New Year’s Flood Event 1997

1998 • Carson River Conference - Integrated Watershed Planning Implemented

1999 • Churchill County Joins

2001 • Alpine County California becomes a CWSD Member Structure of CWSD 14 Board Members • 6 counties / 2 states Funding • Property Tax • Grants (State, Fed., & others) Staffing • 2 Full-Time • 3 Part-Time What We Do Balancing Water Supplies

Environmental

Agricultural Domestic Watershed’s Current Water Supply Situation • Fully appropriated • 95 %+ for Agricultural Use • Groundwater basins - over appropriated • Actual GW pumping < Appropriated • Limited Upstream storage • Water quality problems • Runoff Pattern Changes Water Issues

• Perennial Yield vs. System Yield • Wet Water vs. Paper Water • Surface vs. Groundwater • Interbasin Transfers • Water Quality • Use of Reclaimed Water • Critical Management Area • Climate Change Perennial Yield versus System Yield

• What is Perennial Yield • Limitation Regarding Perennial Yield • System Yield • Examples – • Carson City – Eagle Valley • Perennial Yield – 4,900 AF • System Yield – 9,000 AF Wet Water versus Paper Water

Churchill Valley Groundwater Basin Pumpage Inventory 20132013 Actual Committed Ground Pumpage Category Water Resource (AF) (AF) Irrigation 3,938 581 Commercial/ Stock/ Industial 446 54 Quasi- Municipal 6,461 530 Domestic Wells N/A 1,405 Total 10,845 2,570 Perennial Yield = 1,600 AF System Yield = ? Surface Water versus Groundwater

• Groundwater Pumping impacts river flows but there’s more to the story. USGS Upper Carson River Study

• In 2009, USGS completed the study: Analysis of Streamflow Trends, Ground- Water and Surface-Water Interactions, and Water Quality in the Upper Carson River Basin, Nevada and California

Total Groundwater Pumping Upper Carson River Basin USGS Findings

• 1970 – 2005 GW pumping increased from < 8,000 AF/YR to 50,000 AF/YR • Statistical analyses of mean annual streamflow changes were not measurable to Lahontan Reservoir • Decrease in streamflow caused by increase pumping is offset by decrease in irrigation. OTHER MAN MADE AND NATURAL CONSIDERATIONS

• Change in irrigation practices • Laser-Leveling Fields • Sprinkler Application • Changes in runoff patterns • Alpine Federal River Decree

Inter-Basin Transfers

• Inter-Basin Transfers have been happening for a long time in Nevada • Marlette/Hobart System – 1873 • Intertie between Carson City/Dayton • Intertie between Town of Minden & Carson City (Water Quality) Ground Water Quality

USGS Nitrate Study – The Distribution and Modeling of Nitrate Transport in the Carson Valley Alluvial Aquifer, Douglas County, Nevada Ruhenstroth Area - Douglas County

Use of Reclamation Water

• 27 % decrease of Reclaimed Water imported from Lake Tahoe since mid - 1990s.

• 14% decrease of local reclaimed water from the mid - 2000s to present.

• Majority of reclaimed water used for irrigating fields, parks, and golf courses. CRITICAL MANAGEMENT AREAS • Dealing with Critical Management Areas • Sub-basins? • Dealing with over allocated groundwater basins? • Dealing with groundwater sub-basins where water levels are dropping? GROUNDWATER ASSESSMENT

• Overall the groundwater basins in the Watershed are not being over drafted. • There are areas of concern: • Ruhenstroth area • Fish Springs area • Johnson Lane area • Mark Twain area • Stagecoach area • South Silver Springs area • Churchill County area CLIMATE CHANGE

Runoff Changes Monthly Streamflow – East Fork

0.35 East Fork 0.30 0.25 1941-1974 1975-2009 0.20 0.15 0.10

Fraction of Annual Flow Annual of Fraction 0.05 0.00 Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep The Stakeholder Affiliate Group

Nevada Department of Water Resources Tahoe Regional Planning Agency The Nature Conservancy Truckee Meadows Water Authority Stillwater Wildlife Refuge Pyramid Lake Paiute Tribe Washoe Tribe Carson Valley Conservation District Carson River Subconservancy Truckee-Carson Irrigation District City of Fernley Fallon Shoshone Paiute Tribe Questions?