Geology topics

Ute Wiegand

Publications and source records attributed to Ute Wiegand.

4 recordsLinked to original sources

USGS2011

Low-flow characteristics of Virginia streams

Low-flow annual non-exceedance probabilities (ANEP), called probability-percent chance (P-percent chance) flow estimates, regional regression equations, and transfer methods are provided describing the low-flow characteristics of Virginia streams. Statistical methods are used to evaluate streamflow data. Analysis of Virginia streamflow data collected from 1895 through 2007 is summarized. Methods are provided for estimating low-flow characteristics of gaged and ungaged streams. The 1-, 4-, 7-, and 30-day average streamgaging station low-flow characteristics for 290 long-term, continuous-record, streamgaging stations are determined, adjusted for instances of zero flow using a conditional probability adjustment method, and presented for non-exceedance probabilities of 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.05, 0.02, 0.01, and 0.005. Stream basin characteristics computed using spatial data and a geographic information system are used as explanatory variables in regional regression equations to estimate annual non-exceedance probabilities at gaged and ungaged sites and are summarized for 290 long-term, continuous-record streamgaging stations, 136 short-term, continuous-record streamgaging stations, and 613 partial-record streamgaging stations. Regional regression equations for six physiographic regions use basin characteristics to estimate 1-, 4-, 7-, and 30-day average low-flow annual non-exceedance probabilities at gaged and ungaged sites. Weighted low-flow values that combine computed streamgaging station low-flow characteristics and annual non-exceedance probabilities from regional regression equations provide improved low-flow estimates. Regression equations developed using the Maintenance of Variance with Extension (MOVE.1) method describe the line of organic correlation (LOC) with an appropriate index site for low-flow characteristics at 136 short-term, continuous-record streamgaging stations and 613 partial-record streamgaging stations. Monthly streamflow statistics computed on the individual daily mean streamflows of selected continuous-record streamgaging stations and curves describing flow-duration are presented. Text, figures, and lists are provided summarizing low-flow estimates, selected low-flow sites, delineated physiographic regions, basin characteristics, regression equations, error estimates, definitions, and data sources. This study supersedes previous studies of low flows in Virginia.

Virginia↗

USGS2011

Peak-flow characteristics of Virginia streams

Peak-flow annual exceedance probabilities, also called probability-percent chance flow estimates, and regional regression equations are provided describing the peak-flow characteristics of Virginia streams. Statistical methods are used to evaluate peak-flow data. Analysis of Virginia peak-flow data collected from 1895 through 2007 is summarized. Methods are provided for estimating unregulated peak flow of gaged and ungaged streams. Station peak-flow characteristics identified by fitting the logarithms of annual peak flows to a Log Pearson Type III frequency distribution yield annual exceedance probabilities of 0.5, 0.4292, 0.2, 0.1, 0.04, 0.02, 0.01, 0.005, and 0.002 for 476 streamgaging stations. Stream basin characteristics computed using spatial data and a geographic information system are used as explanatory variables in regional regression model equations for six physiographic regions to estimate regional annual exceedance probabilities at gaged and ungaged sites. Weighted peak-flow values that combine annual exceedance probabilities computed from gaging station data and from regional regression equations provide improved peak-flow estimates. Text, figures, and lists are provided summarizing selected peak-flow sites, delineated physiographic regions, peak-flow estimates, basin characteristics, regional regression model equations, error estimates, definitions, data sources, and candidate regression model equations. This study supersedes previous studies of peak flows in Virginia.

Virginia↗

USGS2009

Annual Maximum Stages and Discharges of Selected Streams in Virginia through 2007

Annual maximum stages and discharges for continuous-record and partial-record streamflow-gaging stations in Virginia are summarized through the 2007 water year. Data are included for over 500 active and discontinued streamflow-gaging stations operated by the U.S. Geological Survey, the Virginia Department of Environmental Quality, and other agencies for which 2 or more years of record are available. Additional information is provided for each station, including a brief description of gage location, drainage area, type of gage, vertical datum if known, method of development of the stage-discharge relation, bankfull stage if known, degree of regulation upstream from each gage, and pertinent remarks about historical data or local conditions that may affect peak flows.

Open-File Report↗

USGS2006

Drainage Areas of Selected Streams in Virginia

Drainage areas were determined for more than 1,600 basins in the three major river basins of Virginia -- the North Atlantic Slope, South Atlantic Slope, and Ohio River Basins. Drainage areas range from 0.004 square mile to 7,866 square miles. A geographic information system was used to digitize and store data associated with the drainage basins. Drainage divides were digitized from digital U.S. Geological Survey 7.5-minute, 1:24,000-scale, topographic quadrangles using procedures recommended by the Subcommittee on Hydrology, Federal Interagency River Basin Committee. Digital drainage basins were quality assured, polygons of the closed drainage basins were generated, and drainage areas were computed.

Open-File Report↗