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Western U.S. Observed Hydrology & Vegetation Changes. Earlier Greening. Less Snow, More Rain. Earlier Snowmelt Runoff. Stewart et al., 2005. Less Spring Snowpack. Increasing Temperature. Cayan et al., 2001. Key Challenges for Reclamation.
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Western U.S. Observed Hydrology & Vegetation Changes Earlier Greening Less Snow, More Rain Earlier Snowmelt Runoff Stewart et al., 2005 Less Spring Snowpack Increasing Temperature Cayan et al., 2001
Key Challenges for Reclamation • Understand how climate variability and change can affect Western water supply and demand, and Reclamation delivery of water given operational constraints (i.e. environmental constraints, flood constraints) • Bring science and technology to bear on the needs of water resources managers • Address goals of internal programs and authorizations where climate change is a factor
Reclamation Climate Studies • Climate Change and Water Working Group (CCAWWG): NOAA, USGS, USACE, EPA, NASA, FEMA collaboration • Climate change is occurring; effects differ regionally. • Water resources management could be affected; hydroclimate conditions becoming non-stationary. • Climate change is one of many challenges facing water managers. From USGS Circular 1331 (Brekke et al. 2009) 2009 SECURE Water Act (PL 111-11) Secretarial Order 3289 and 3297 – WaterSMART • Federal agencies that conduct water management have a responsibility to take a lead role in assessing risks to the water resources and to develop adaptation and mitigation strategies • Establishes Landscape Conservation Cooperatives, Climate Science Centers, and Basin Studies http://www.usbr.gov/climate
West-Wide Climate Risk Assessments (WWCRA) - Hydrologic Projections (2011) SECURE Report to Congress, 2011 focus on median changes; future reports have broader scope 112 Transient Climate Projections… http://gdo-dcp.ucllnl.org/downscaled_cmip3_projections/dcpInterface.html 112 Transient Hydrologic Projections covering western U.S.… Analyses of Period-changes in climate and hydrology Peer Review 8 “big basin” VIC hydrology model-apps from Univ. of WA… Technical Report, data-development (TSC 86-68210, March 2011) Data-service, Reclamation and broader public use (Summer 2011) http://www.usbr.gov/WaterSMART/wwcra.html
Change Through Time Colorado River Annual Max Weekly Runoff 2020s 2070s 2050s Temp Precip • Flood Control Implications Annual Min Weekly Runoff Snow • Environmental Flow Implications HUGE CAVEAT – e.g. calibration, validation
annual Dec-Mar Apr-Jul SECURE Report: Westwide Impacts (e.g. annual and seasonal runoff) 2020s-1990s 2050s-1990s http://www.usbr.gov/climate 2070s-1990s