Base-Flow Characteristics of Streams in the Valley and Ridge, Blue Ridge, and Piedmont Physiographic Provinces of Virginia

摘要: Growth within the Valley and Ridge, Blue Piedmont Physiographic Provinces of Virginia has focussed concern about allocation surface-water flow increased demands on ground-water resources. Thepurpose this report is to (1) describe base-flow characteristics streams, (2) identify regional differences in these characteristics, (3) describe, if possible, potential yields basins basis characteristics. Base-flow are presented for streams Virginia. The provinces separated into five regions: Piedmont/Blue Ridge transition, (4) northern, (5) southern. Different statistics, which represent streamflows predominantly comprised base flow, were determined 217 continuous-record streamflow-gaging stations from historical mean daily discharge 192 partial-record by means correlation measurements. Variability represented a duration ratio developed during investigation. Effective recharge rates also calculated. Median values different statistics range 0.05 cubic foot per second square mile 90-percent streamflow-duration curve 0.61 flow. An excellent estimator transition region southern 50-percent curve, but it tends underestimate remaining regions. variability index ranges 0.07 2.27, with median value 0.55. 33.07 inches year, 8.32 year. Differences exist between discharges regions higher than those Results statistical analysis indicate that can be ranked terms highest lowest as follows: southern, northern. consistently lower relative other regions, whereas northern show opposite pattern. group rankings used designate yield In addition, an approach investigation assigns rank basin according quartiles located. Both procedures Piedmont/ have moderate-to-high low-to-moderate yield.