C&EE 259A: Selected Topics in Environmental and Water Resources Engineering
Harnessing advances in climate and streamflow prediction and projection to improve Colorado River water management by Dr. Andy W. Wood, NOAA/NWS Colorado Basin River Forecast Center, Salt Lake City, Utah
Tuesday, May 17, 2011
4275 BOELTER HALL
Colorado River water serves a wide range of uses in seven southwestern US states and is central to the economic and social development of the region. The 1922 Colorado River Compact and the Mexican Water Treaty of 1944 together obligated 16.5 million acre feet (maf) of water per year to the river’s stakeholders. We now know that this was an over-allocation of a resource that exhibits significant interannual and decadal variability and has averaged nearer 13.5 maf over the last 3 centuries. Massive reservoirs that offer storage equaling four years of annual river flow have helped to buffer demand from supply variations, but two pressures appear to be drawing this period of unsteady balance to an inexorable close. Steady water rights development has pushed demand to meet supply, and the effects of climate variability appear increasingly to be compounded by those of climate trends. In response, the primary water management agency for the Colorado Basin, the US Bureau of Reclamation, has funded a range of efforts toward understanding the basin’s hydrologic sensitivity in the face of climate change, as well improving the quality of tools and approaches for predicting and managing rivers and reservoirs and the breadth of policy options for managers and stakeholders. This presentation provides insight into the basin’s water management challenge, including findings of climate change analyses performed by Reclamation. A second focus is the activities the NOAA Colorado Basin River Forecast Center (CBRFC), which produces two-year lead streamflow forecasts to support reservoir release decisions. Reclamation is building probabilistic reservoir management tools while CBRFC is currently pursuing a multi-faceted strategy to augment traditional statistical and dynamical (model-based) streamflow predictions. Components of the latter effort include: (a) the incorporation of dynamical climate forecasts; (b) the exploration of new statistical approaches to leverage climate system state information; (c) the establishment of a climate and flow forecasting testbed; and (d) the development of an objective strategy for combining multiple predictions from both dynamical and statistical sources. Continuing challenges include negotiating the management frameworks involving multiple operational agency partners and a reinvention of the forecasting culture within the River Forecast Centers.