MITIGATING IMPACTS OF A SEVERE SUSTAINED DROUGHT ON COLORADO-RIVER WATER-RESOURCES

We evaluated the effects of institutional responses developed for copi ng with a severe sustained drought (SSD) in the Colorado River Basin o n selected system variables using a SSD inflow hydrology derived from the drought which occurred in the Colorado River basin from 1579-1616. Institutional responses considered are reverse equalization, salinity reduction, minimum flow requirements, and temporary suspension of the delivery obligation of the Colorado River Compact. Selected system va riables (reservoir contents, streamflows, consumptive uses, salinity, and power generation) from scenarios incorporating the drought-coping responses were compared to those from Baseline conditions using the cu rrent operating criteria. The coping responses successfully mitigated some impacts of the SSD on consumptive uses in the Upper Basin with on ly slight impacts on consumptive uses in the Lower Basin, and successf ully maintained specified minimum streamflows throughout the drought w ith no apparent effect on consumptive uses. The impacts of the coping responses on other system variables were not as clear cut. We also ass essed the effects of the drought-coping responses to normal and wet hy drologic conditions to determine if they were overly conservative. The results show that the rules would have inconsequential effects on the system during normal and wet years.