A GIS Assessment of the Total Loads and Water Quality in the Corpus Christi Bay System
By Ann Marie Quenzer, M.S.E. and David R. Maidment
A method is presented for determining raster maps of mean annual water flow and pollutant loading from the land surface, and for determining the resulting concentrations in receiving water bodies. The method is illustrated by application to the Corpus Christi Bay system in South Texas. A mesh of 100m digital elevation model cells is laid over the drainage area and cell to cell connectivity established to link each land surface cell with a corresponding water body segment. Non-point source constituent loads are determined for each cell as the product of runoff and expected mean concentration, and accumulated down to the bay system. Point source and atmospheric loads are added, water quality computed in each bay system, and compared to observed data. A strong South to North runoff gradient is observed in the study area. The majority of the constituent loading comes from non-point sources, except for oil and grease, which arise mainly from point sources. Nitrogen and phosphorus concentrations in the bay system are reproduced reasonably well provided a decay rate of 0.01-0.02 day-1 is used. Oil and grease are reproduced well as conservative constituents. The computed metals concentrations are low and suggest a significant source in sediment or elsewhere that is presently not accounted for.
A GIS Assessment of the Total Loads and Water Quality in the Corpus Christi Bay System
By Ann Marie Quenzer, M.S.E. and David R. Maidment
The highlighted links that follow are connected to Adobe pdf files of the corresponding material. To view them you must have the Adobe Acrobat Reader 3.0.
View the Report...(1.6MB)
These materials may be used for study, research, and education, but please credit the authors and the Center for Research in Water Resources, The University of Texas at Austin. All commercial rights reserved. Copyright 1998 Center for Research in Water Resources.