What is the effect of LiDAR-derived DEM resolution on large-scale watershed model results?

This paper examines the effect of raster cell size on hydrographic feature extraction and hydrological modeling using LiDAR derived DEMs. LiDAR datasets for three experimental watersheds were converted to DEMs at various cell sizes. Watershed boundaries and stream networks were delineated from each DEM and were compared to reference data. Hydrological simulations were conducted and the outputs were compared. Smaller cell size DEMs consistently resulted in less difference between DEM-delineated features and reference data. However, minor differences been found between streamflow simulations resulted for a lumped watershed model run at daily simulations aggregated at an annual average. These findings indicate that while higher resolution DEM grids may result in more accurate representation of terrain characteristics, such variations do not necessarily improve watershed scale simulation modeling. Hence the additional expense of generating high resolution DEM’s for the purpose of watershed modeling at daily or longer time steps may not be warranted. 2014 Elsevier Ltd. All rights reserved. Software and data availability Name BASINS 4.0 (Better Assessment Science Integrating point & Non-point Sources) with a non-proprietary, open source, free GIS system, MapWindow (www. MapWindow.org) Developer U.S. EPA with AquaTerra Consultants and Idaho State University Contact http://www.aquaterra.com/contact/index.php the effects of LiDAR-derived used for streamflow simula, [email protected] Availability and cost The software is available for free download at USEPA (United States Environmental Protection Agency) website. Mapwindow is an open source programmable GIS (VB, Cþþ, .NET, and Active controls) that supports manipulation, analysis, and viewing of geospatial data and associated attribute data in several GIS data formats.