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Approaches to Continental Scale River Flow RoutingBy Kwabena Asante, David R. Maidment, James S. Famiglietti and Francisco Olivera ABSTRACT Recent concerns about global climate change and a series of large-scale
hydrologic events such as the Mid-West flood of 1993 and the El Nino
of 1997 have focused attention on the need to track the flow of water
through the entire hydrologic cycle. On the land surface, databases
of routing parameters and routing models are required to describe the
movement of runoff generated by Global Circulation Models (GCMs) and
other soil water balance models over the earth´s surface. In this study,
a terrain analysis is performed using 30 arcsecond Digital Elevation
Model (DEM) data to develop a global database of terrain derived routing
parameters. A computationally efficient grid based routing model, called
a source to sink (STS) model, is implemented in this study. It routes
flow directly from the point of generation to the desired observation
point. The STS model also allows for easy interaction with models of
other phases of the hydrologic cycle by incorporating the boundaries
of their modeling units into the definition of its own modeling units.
A continental scale STS model is created and parameterized for each
continent using datasets derived from the terrain analysis. A process
is defined for determining additional velocity and dispersion parameters
from observed flow data. Another continental scale routing model is
developed using the watershed based approach of the Hydrologic Modeling
System (HMS). Hydrologic elements and routing parameters for the HMS
model are derived from the same terrain data used in parameterizing
the STS model. Basin responses from the two models are compared for
various spatial and temporal resolutions and parameter distributions
to determine the implications of their respective conceptual models.
These comparisons show that basin responses in the STS model are relatively
independent of spatial and temporal scale while the HMS model is scale
dependent with regard to both spatial and temporal resolution. Basin
responses for a fine resolution HMS models were successfully duplicated
in a STS model for both the uniform and non-uniformly distributed velocity
and dispersion parameter case. The highlighted links that follow are connected to Adobe pdf files of the corresponding material. To view them you must have the Adobe Acrobat Reader 3.0. View the Report...(2.7MB)
These materials may be used for study, research, and education, but please credit the authors and the Center for Research in Water Resources, The University of Texas at Austin. All commercial rights reserved. Copyright 1997 Center for Research in Water Resources. |
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