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USGS Congressional Briefing Washington, DC April 27, 2007 Preparing Water Managers for Drought and Climate Change in the Southwest Katharine Jacobs Executive Director Arizona Water Institute
Arizona Water Institute A consortium of Arizona’s universitiesfocused on improving quality of life in Arizona and throughout the world through water research, education and technology… 400 water related faculty/staff 3 state agencies Public and private partners
Data from Woodhouse et al., 2006 Water Resources Research Water-supply planning based on anomalous period Sustained droughts in 1100s and 1500s Virgin runoff (million acre-ft) Data from Meko et al., accepted, Geophysical Res. Tree rings give long-term perspective on water supply and drought Reconstructed Colorado River Flows
Implications of Climate Change • The past is not an analog for the future; even long term and severe droughts of the past are not likely to frame future drought extremes • Lack of stationarity: implications for water management at multiple scales Stott et al. (2000)
Connecting Science and Water Management • Climate change impacts on flows in the Colorado are significant; majority of models project 10-40% reductions in runoff • Temperature affects both supply and demand • Current inflows to Powell at 50% of normal; below normal 7 of last 8 years • Shortage sharing and reoperation rules now being developed
Increasing demand, decreasing supply Arizona Population 1900-2100 • Population growth, changing values and over-allocation mean that future “normal” droughts will have greater impacts and lead to more conflict • Potential for multi-decadal drought emerging as a concern Global Institute of Sustainability, ASU
Climate change impacts on Arizona • Serious implications for water supply and habitat • Central Arizona Project has the lowest priority on the river • The Colorado River supplies almost half of Arizona’s water Multiple-stress context; increasing demands from other basin states National Drought Mitigation Center
Adaptation requires better information • Need to improve monitoring and data collection to identify and respond to regional and local trends, and allow for better early warning systems • Focus on critical or vulnerable systems • Need better data access and retrieval Salt River Project Monitoring Station
Adaptation options • Drought planning and conservation are no-regrets strategies • Conjunctive management offers multiple benefits However, water either comes from the environment or from a current use (impacts) • Effects on groundwater of drought and climate change need more analysis Lower Santa Cruz Replenishment Project
Adaptation: Revise engineering assumptions • Re-evaluate engineering assumptions re: potential for more extreme events and longer-term droughts • Extremes could be of a different nature • Variability may be outside of the range of our experience • Abrupt changes may result in limited time to respond • Connect energy and water Central Arizona Project • Technological solutions: • desalination, • weather modification, • expansion of surface storage • integration of delivery systems
Adaptation: Increased use of forecasting tools • Improve understanding of climate drivers and variability at multiple time scales • Produce better predictive information (based on probabilistic forecasts) Courtesy of Konstantine Georgakakos Improve linkages between large-scale climate models (GCMs) and local conditions through regional hydrologic models.
Adaptation: Decision Support • Impacts are occurring today -- we need to begin adaptation efforts. • Decision support systems need to focus on specific decisions at regional and local scales. • Explain the climate drivers, allowing managers to evaluate the utility and basis of the information. • Encourage adaptive management and institutional flexibility. • Significant new resources are required for adaptation in the near term.
Conclusions • The question for water managers is no longer whether climate change is happening. • The question is what are we going to do about it?