Virginia StreamStats

StreamStats for Virginia can be used to estimate the magnitude of peak flows for Virginia streams under rural, natural streamflow conditions at the 2-, 5-, 10-, 25-, 50-, 100-, and 200-year recurrence intervals, and under urban conditions at the 1.005-, 1.01-, 1.05-, 1.11-, 1.25-, 1.49-, 2.0-, 2.3-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year recurrence intervals. StreamStats for Virginia may also be used to estimate the magnitude of low flows for Virginia streams under rural, natural streamflow conditions at the 1-, 4-, 7-, and 30-day average 1.11, 1.25, 1.43, 1.67, 2.0, 2.5, 3.3, 5, 10, 20, 50, 100, and 200 year recurrence intervals. In addition to streamflow statistics, basin characteristics for a variety of land cover, elevation, precipitation, soils, streams, and geology are available for download with watershed delineations. The reports below present the equations used to estimate the flow statistics, describe the errors associated with the estimates, and describe the methods used to develop the equations and to measure the basin characteristics used in the equations. Users should familiarize themselves with the reports before using StreamStats to obtain estimates of streamflow statistics for ungaged sites.

• Austin, S.H., Krstolic, J.L., and Wiegand, Ute, 2011, Low-flow characteristics of Virginia streams: U.S. Geological Survey Scientific Investigations Report 2011–5143, 122 p.
• Austin, S.H., Krstolic, J.L., and Wiegand, Ute, 2011, Peak-flow characteristics of Virginia streams: U.S. Geological Survey Scientific Investigations Report 2011–5144, 106 p.
• Austin, S.H., 2014, Methods and equations for estimating peak streamflow per square mile in Virginia’s urban basins: U.S. Geological Survey Scientific Investigations Report 2014–5090, 25 p.

Click on this link to obtain general information on the Virginia application, as well as specific sources and computation methods for basin characteristics. 

NOTE: Virginia StreamStats operates in a unique manner when a delineated basin has drainage area that is in multiple hydrologic regions. Normally in these cases, StreamStats provides flow estimates using the equations for each hydrologic region and then produces final estimates that weight the estimates from each hydrologic region according to the percentage of the region that is in the delineated basin. However, only the regression equations for the hydrologic region with the largest proportion of area within the delineated drainage basin are used to provide flow estimates for Virginia StreamStats.