Browsing by Author "Carr, Jan C."
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- An interactive, computer-based management system for hydrologic dataCarr, Jan C.; Shanholtz, Vernon O.; Dillaha, Theo A. III; Wolfe, Mary Leigh; Stavros, Robert W. (Virginia Agricultural Experiment Station, 1985-04)An automated system has been developed to digitize the continuous traces generated by strip chart recorders. The system is comprised of an electronic digitizer, computer terminal, mainframe computer, and custom designed software. The digitizer is connected to a computer terminal with a cassette tape operating in local mode when a chart is being digitized. After digitization is completed, an interactive processing system consisting of a system controller and a series of Fortran programs is accessed to perform various data management, data error diagnostics, data reduction, data summary, and graphics functions.
- A Model for evaluating the effect of land uses on flood flowsRoss, Burton Blake; Shanholtz, Vernon O.; Contractor, Dinshaw N.; Carr, Jan C. (Water Resources Research Center, Virginia Polytechnic Institute and State University, 1978)A basic problem facing modelers of natural watershed systems has been that of accounting for heterogeneities that generally are present. It has long been recognized that such factors as soil, cover, management, and slope tend to cause heterogeneity in the runoff response...
- A Model for predicting flood hazards due to specific land-use practicesRoss, Burton Blake; Li, Elizabeth A.; Shanholtz, Vernon O.; Carr, Jan C. (Water Resources Research Center, Virginia Polytechnic Institute and State University, 1976)This investigation developed a finite element model for mathematically routing overland and channel flow when rainfall excess is known. To determine rainfall excess, a procedure was developed to subdivide a drainage area into similarly responding units, defined as hydrologic response units. These units were functions of soil texture, soil depth, land use, and hydrology group classification. A computer model, based on the Mein and Larson and Holtan infiltration equations, was developed to generate excess precipitation for each hydrologic response unit. A finite element grid, devised for both the watershed and the main streams, allowed use of the hydrologic response units within an element to obtain weighted rainfall excess values for each element. A one-dimensional finite element scheme, in conjunction with Galerkin's residual method, simulated overland and open channel flow. Hurricane Camille (August, 1969) provided an event by which the model was tested and calibrated on the South River watershed in Augusta County, Virginia. Having the ability to report changes in land use, the finite element procedure allowed several arbitrary land-use changes to be incorporated into the model in order to observe the river's response under flood conditions. The effects of changes in the number and size of the elements in the watershed and in the streams also were observed, along with changes in the size of the time increment.