HR: 1340h
AN: H43E-1673    [Abstracts]
TI: The Comparison of Hydrologic Distributed Models Computed Using Different Digital Elevation Data. An Example in the Umbria Region, Central Italy
AU: Zucca, F
EM: francesco.zucca@unipv.it
AF: Dipartimento di Scienze della Terra, Universita' di Pavia, Via A. Ferrata 1, Pavia, PV 27100, Italy
AU: Zizioli, D
EM: davide.zizioli@manhattan.unipv.it
AF: Dipartimento di Scienze della Terra, Universita' di Pavia, Via A. Ferrata 1, Pavia, PV 27100, Italy
AU: * Taramelli, A
EM: ataram@ldeo.columbia.edu
AF: Lamont Doherty Earth Observatory of Columbia University, Route 9W, Palisades, NY 10964, United States
AU: Reichenbach, P
EM: Paola.Reichenbach@irpi.cnr.it
AF: CNR IRPI, Via della Madonna Alta 126, Perugia, PG 06128, Italy
AU: Ardizzone, F
EM: Francesca.Ardizzone@irpi.cnr.it
AF: CNR IRPI, Via della Madonna Alta 126, Perugia, PG 06128, Italy
AB: The demand for hydrologic prediction tools that utilize information on spatial variations in precipitation and land surface characteristics drive the development of spatially distributed hydrologic models. Several studies have found that spatially distributed hydrological models are sensitive to digital elevation models (DEMs) resolution and vertical accuracy. DEM is a crucial input in hydrologic models. Spatially distributed features, such as number of stream reaches, Strahler order, total length of the stream network and watershed area depend on DEM resolution and quality. This study evaluates the effect of three different DEMs on the spatial distribution of the number of stream reaches (Strahler order), of Horton's parameters variations, of the total length of the stream network and of the watershed area. These components are the main input for hydrologic modelling. Their structure (i.e. number of features) and spatial attributes (length and area) have considerable effect on modelling process and final output. The analysis is carried out in the Umbria region (central Italy) using three different DEMs derived from ASTER data, SRTM data, and a 25m resolution DEM derived from the interpolation of contour lines obtained from 1:25.000 scale topographic maps. The study analyzes the relationship between mean slope and mean elevation for computed watersheds and compares values of the derivatives for each pair of DEMs. Where blue lines derived from topographic maps are available, will be compared with the stream network computed automatically using different algorithms from the three DEMs. The aim of this part of the work is to illustrate how several methods- algorithms of channel extraction (D8, RHO8, LTD) are sensitive both to grid size and different morphological signature proper of each data set. The synthetic drainage networks are also classified in terms of stream ordering. The final overall results will help to translate the error in elevation data set into the error in hydrologic model input and in predictions of the output (i.e. discharge and time lag).
DE: 1804 Catchment
DE: 1819 Geographic Information Systems (GIS)
DE: 1879 Watershed
SC: Hydrology [H]
MN: 2007 Fall Meeting