managingwaterinthewest–coloradoriverupdate-southern.ppt

Biased corrected using the Ratio method Lot’s of variablity in any given year Average shows about 10% decrease in annual average inflow * * Define current and future imbalances in water supply and demand within the study area over a 50-year horizon, particularly in light of potential impacts of climate change Assess the risks to Basin resources including water deliveries, hydroelectric power generation, recreation, fish and wildlife and their habitat, water quality, flow and water-dependent ecological systems, and flood control management Develop and evaluate adaptation and mitigation strategies to resolve those imbalances REMIND THEM THAT WE HAVE A WEB SITE: address on last slide Colorado River Update Terry Fulp Deputy Regional Director Bureau of Reclamation, Lower Colorado Region Southern California Water Dialogue July 28, 2010 Colorado River Basin Operation governed by the Law of the River including: Colorado River Compact (1922) Boulder Canyon Project Act (1928) U.S. Mexican Water Treaty (1944) Colorado River Storage Project (1956) Supreme Court Consolidated Decree (1964 and following) Colorado River Basin Project Act (1968) Variable hydrology 60 million acre-feet of storage capacity System operated on a tight margin Water Budget at Lake Mead Given basic apportionments in the Lower Basin, the allotment to Mexico, and an 8.23 maf release from Lake Powell, Lake Mead storage declines Inflow = 9.0 maf (release from Powell + side inflows) Outflow = - 9.6 maf (AZ, CA, NV, and Mexico delivery + downstream regulation and gains/losses) Mead evaporation loss = - 0.6 maf Balance = - 1.2 maf Data based on long-term averages Natural FlowColorado River at Lees Ferry Gaging Station, ArizonaWater Year 1906 to 2009 State of the System (1999-2010) WY Unregulated inflow into Powell % of Average Powell and Mead Storage maf Powell and Mead % Capacity 1999 109 47.59 95 2000 62 43.38 86 2001 59 39.01 78 2002 25 31.56 63 2003 52 27.7