|Goodrich, David - Dave|
Submitted to: American Water Resources Association Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 9/1/1996
Publication Date: N/A
Interpretive Summary: Geographic information systems (GISs) are computer-based tools that assist in the display and management of spatial information such as can be found on traditional maps. Because of the efficient manner with which they store data, a GIS can help researchers investigate the complex processes that shape the land. Flooding and erosion are significant problems in the southwestern United States, and a great deal of research and effort is directed toward the prediction of floods and their impact on the land and people. This project used both field research and computer programs to estimate characteristics of stream channels important to flood prediction. It was found that a GIS can be effectively used to predict the shape of a channel. This information will benefit other hydrology and flood research projects because it reduces the amount of time spent doing field work.
Technical Abstract: Offering a significant savings in time and labor, geographic information systems (GIS) have improved the efficiency and repeatability of geomorphologic assessment and hydrologic model parameterization. The objective of this study was to couple field measurements, spatial data, and GIS analytical capabilities to improve our understanding of channel geomorphologic processes. A high-resolution GIS database was constructed for the Walnut Gulch Experimental Watershed, and field measurements of channel characteristics (cross-sectional area, width, and depth) were taken at 222 sample points. To characterize the areas contributing runoff to each of the sample points a suite of GIS tools was developed in GRASS and ARC/INFO. A routine capitalizing on the arc-node topology of stream vector data was created to order the extensive channel network on Walnut Gulch. Strong predictive relationships were derived between channel shape variables and watershed characteristics. Channel cross-sectional area and width were found to be significantly related to channel order, upstream watershed size, and maximum contributing flow length within a watershed. The ability to accurately and efficiently model channel characteristics in the southwestern United States offers the potential for improving the performance of hydrologic models as well as aiding the integration of hydrologic models and GIS.