Phase I summary and phase II plan for comparing regulated with unregulated streamflow in the Yakima River at Union Gap, Washington

A preliminary investigation of the effects of reservoir storage and canal diversion on the flow of the Yakima River at Union Gap , Washington indicates that those effects are measurable and substantial--on the average causing a reduction of roughly one-quarter from the unregulated flow. Preliminary computations of the unregulated flow of the Yakima River at Parker (near Union Gap) for the 1978 water year using the U.S. Bureau of Reclamation 's SSARR model indicate, however, that the computed flow figures contain inaccuracies. Further investigation of the model indicates that the inaccuracies can be substantially reduced by data checking and by using additional discharge records to improve the estimation of local inflows. (USGS)