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Francisco Olivera, Ph.D., P.E. – Assistant Professor ([email protected])
Srikanth Koka – Graduate Research Assistant ([email protected])
Texas A&M University – Department of Civil Engineering - College Station, Texas
Mississippi River Climate & Hydrology Conference
May 13 – 17, 2002
New Orleans, LA
Network Topologic and
Due to the inherent spatial complexity of large hydrologic systems, for modeling purposes, rather than applying lumped models to represent entire basins, it is better to subdivide them into elementary flow elements organized as networks by virtue of their topologic relations. Likewise, each element should have different hydrologic properties to account for the terrain spatial variability and different hydrologic behavior to account for the different flow processes.
Hydrologic topology is the relation of the flow elements of a system to one another, so that each of them "knows" which other elements are upstream and which are downstream. Establishing the hydrologic topology is fundamental for flow routing as well as for tracking constituent particles transported by water.
Use of vector data, as opposed to raster data, has the advantage that each element represents a real-world flow element and, consequently, sets a better ground for physically-based modeling, not to mention that overall it is more accurate and better suited for modeling large study areas.
Mississippi River System
Downstream Flow Length
(1) Potential Mean Flow (m3/sec) = Weighted Drainage Area (mm Km2/year) , (2) Value for 1999, (3) Value for 2000, (4) Value for 1995
Hydrologic Topology GIS Tools
For every point of the network, the tools:
Mean Annual Precipitation
Longest Flow Path
Weighted Drainage Area
0 – 10 106 mm Km2/year
10 – 100 106 mm Km2/year
802 – 1076 mm/year
100 – 500 106 mm Km2/year
500 – 1000 106 mm Km2/year
1000 – 2711 106 mm Km2/year