Preparing Water Managers for Drought and Climate Change in the Southwest Katharine Jacobs Executive Director Arizona Water Institute USGS Congressional Briefing Washington, DC April 27, 2007

A consortium of Arizona’s universities focused 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 Arizona Water Institute

Water-supply planning based on anomalous period Data from Woodhouse et al., 2006 Water Resources Research Tree rings give long-term perspective on water supply and drought Reconstructed Colorado River Flows Sustained droughts in 1100s and 1500s Data from Meko et al., accepted, Geophysical Res. Virgin runoff (million acre-ft)

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 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 Arizona Population 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 Technological solutions: desalination, weather modification, expansion of surface storage integration of delivery systems Central Arizona Project

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.

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. Adaptation: Decision Support

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?