In many places in the west, management of water is becoming more intense because systems are because new demands for water are being incorporated into the system, including in-stream flows for ecosystems and recreation. As a result, there is less buffer in the system, and the systems are increasingly sensitive to scarcity related to climate variability and change, more so than when originally designed. Hydro-climatic forecasts are viewed by many as a way to mitigate risks of scarcity by improving forecasts of supply and/or demand, and improving efficiency of use in response to the forecast.

This talk will explore the interaction of climate variability and change with water management in this intensifying water management context, and the potential role for climate information and forecasts in mitigating climate risks in operations and longer-term planning. The combination of increasing climate sensitivity and changing water management polices requires both appropriate hydro-climatic forecasts and also institutions that are able to be adaptive to cope with both anticipated changes and those which are difficult to predict. Characteristics of water management institutions that are likely to be able to cope with the changing policy and climate regimes will be discussed from a case study of the Gunnison basin of western Colorado. The recent history of operations in the basin, including responses to the severe drought of 2002, show that water management institutions in the Gunnison basin have significant adaptive capacity to respond to both policy changes and climate events, and also the capacity to respond to climate forecasts if the appropriate forecasts are available.

Hydro-climate forecasts and other information also have the potential to mitigate risks in longer term planning. For example, planning is underway to °Ère-operate°C USBR reservoirs in the Gunnison basin in order to meet flow needs for four endangered native fishes of the Colorado River, under the Endangered Species Act. Changes to the reservoir operations are considered critical to recovery of the fish, and new operating procedures are likely to be in place for many years, after complete under an Environmental Impact Statement process with will take several years. Climate variability and change have potentially serious implications for meeting the needs of the fish as well as the other authorized purposes of the reservoirs. Some aspects of climate that may challenge the new operating polices are: 1) The effects of multi-year droughts, e.g., periods of 3-7 years of below average snow water equivalent (SWE) and inflows; 2) The effects of decadal-scale periods in which average inflows are below normal, although there may be wet years interspersed; 3) the potential impact of a long-term decrease in reservoir inflows, due to decreases in precipitation and SWE; 3) the potential impact of an earlier spring peak; 4) the opportunity to take advantage of forecasting interannual climate variability to improve the efficiency of reservoir management, both in wet and dry years; 5) the possibility of adaptive management with respect to the effects of climate on water as new understanding about the climate of the region becomes available. These areas of sensitivity suggest areas for research that can mitigate risks of shortage in operational decision-making, but which will also mitigate risks in planning the new operations of the USBR reservoirs on the Gunnison River.