A flow-routing model was used to simulate 17 water years of daily streamflows at five sites. The sites were Mapleton Depot and Newport, Pennsylvania, on the Juniata River, and Harrisburg and Marietta, Pennsylvania, and Conowingo, Maryland, on the Susquehanna River. The purpose for the simulations was to determine the effects of a new reservoir, Raystown Lake, on the low-flow frequency characteristics of these sites. Raystown Lake is on Raystown Branch Juniata River, a tributary to the Juniata River.
Output from a reservoir-regulation model of Raystown Lake was used as input to the flow-routing models. In addition, a reservoir-routing model was developed for the hydroelectric power dams on the lower Susquehanna River.
Low-flow frequency curves, based on the post-Raystown Lake simulated flows, were compared to similar curves based on pre-Raystown observed data. The comparison indicated that operation of the lake will cause estimated increases in the 7-day 10-year low flows ranging from 420 cfs at Mapleton Depot to 290 cfs at Marietta and Conowingo over the 7-day 10-year low flows for pre-Raystown conditions.
Although inherent modeling errors exist in all of these simulated data, the overall quality of the simulated flows and the low-flow frequency curves is considered good. (Woodard-USGS)
