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.