INTEGRATED GIS AND HYDROLOGIC MODELING FOR COUNTYWIDE DRAINAGE STUDY

Using geographic information systems (GIS) technology as an underlying platform for hydrologic and hydraulic models provides an effective mechanism for performing large-area surface water and drainage management studies. An early (1984) personal computer (PC)-based application of GIS technology, combining various commercial software packages, was used to develop a surface water management plan (SWMP) for Polk County in central Florida. At the time of the study, no fully featured GIS package designed to support hydrologic/hydraulic modeling existed on PC platforms. Therefore, a combination of technologies was used, including a computer-aided design (CAD) package, a commercial data-base management system, and a raster-based GIS software package. The HEC-1/HEC-2 models were linked to these packages through custom programming in order to perform the required hydrologic/hydraulic analyses. Ten separate scenarios were examined for each of the 784 subbasins comprising the study area, an extensive modeling effort that would not have been possible without the supporting GIS technology.