|Semmens, D. - US EPA|
|Miller, S. - UNIVERSITY OF WYOMING|
Submitted to: Federal Interagency Hydrologic Modeling Conference
Publication Type: Proceedings
Publication Acceptance Date: April 2, 2006
Publication Date: July 15, 2006
Citation: Semmens, D., Miller, S.N., Goodrich, D.C. 2006. Towards an automated tool for channel-network characterization, modeling, and assessment. Proc. 3rd Fed. Interagency Hydrologic Modeling Conf., April 2-6, 2006. Reno, Nevada. 2006 CDROM. Interpretive Summary: When water quantity or water quality is of interest, watersheds are a natural organizing unit in our landscape. Watersheds gather rainfall, infiltrated water, and runoff and typically discharge that water at a stream location or into a body of water such as a lake or estuary. The pathways and processes that affect runoff generation from a watershed result from a complex interaction of the climate, topography, soils, land cover, and land use. Much of the water coming out of a watershed is carried through stream channels. Numerous computer models have been developed to estimate how a watershed produces runoff from rainfall and snowfall and how it is carried through channels. Good information on the shape and size of channels is required to address many concerns about runoff, floods and water quality. This information is typically very expensive to collect from ground-based field surveys. A new technology called LIDAR (light detection and ranging) can collect detailed data from airplanes that can be used to describe stream channel shape and size. This paper describes a computer-based tool to aid in acquiring channel information from LIDAR data. A test of this tool was conducted on the USDA-ARS Walnut Gulch Experimental Watershed in southeastern Arizona. The LIDAR-based channel data obtained by the tool was compared to ground-based channel measurements with good results. This tool will further assist in the preparation of watershed computer simulation models and running them.
Technical Abstract: Detailed characterization of channel networks for hydrologic and geomorphic models has traditionally been a difficult and expensive proposition, and lack of information has thus been a common limitation of modeling efforts. With the advent of datasets derived from high-resolution mapping techniques such as LIDAR (light detection and ranging), however, it is possible to resolve a great deal of information useful for hydrologic and geomorphic modeling. A channel-characterization tool is being developed to automate the extraction and reduction of data from high-resolution digital elevation models (DEMs) to derive meaningful information about channel morphology at a reach scale. The tool, with some initial guidance from users, will automate the process of extracting cross-sections, at user-defined intervals, perpendicular to channels throughout a watershed channel network. Channel characteristics derived using the new tool were compared with field measurements in southeastern Arizona. The channel characterization tool was designed to compliment the Automated Geospatial Watershed Assessment (AGWA) tool by facilitating parameterization of the KINEROS2 rainfall-runoff-erosion model. Future versions of the tool will incorporate vegetation characterization along riparian corridors. This information will further assist with hydrologic model parameterization, and can also be combined with geomorphic conditions/indicators and output from the hydrologic models to evaluate channel condition and vulnerability on a reach basis.