A digital computer flow-routing model was developed for the Potomac River in order to determine the downstream effects of flow releases from the Bloomington and Savage River Reservoirs. Both reservoirs are located above Luke, Maryland approximately 230 miles upstream from Washington, D. C. The downstream effects of reservoir releases were determined by using the unit-response method of flow routing implemented by a diffusion analogy. Results are in the form of unit response coefficients which are used to route flows downstream from Luke. A 24-hour sustained reservoir release input at Luke will result in 35 percent of the flow arriving at Washington, D.C., during the 4th day after the beginning of the release, followed by 61 percent and 4 percent arriving on the 5th and 6th days, respectively. For a 7-day sustained reservoir release, 47 percent of the flow will arrive during the 1st week, and 53 percent will arrive the 2d week. Two methods were used to estimate the amount of water that goes into channel storage between Luke and Washington, D.C., during sustained reservoir releases. Analysis of the flow-routing results indicates channel storage is equivalent to the volume of water releases over a 3.7-day period. Using channel geometry relationships, that volume is equal to 3.2 days ' release. (USGS)
