TR-20, Project Formulation - Hydrology (1982 Version), Technical Release Number 20. User's Manual

摘要

The TR-20 program provides for hydrologic analyses of a watershed under present conditions and various combinations of land cover/use and structural or channel modifications using single event storm rainfall-frequency data. Output consists of peaks and/or flood hydrographs, their time of occurrence and water surface elevations at any desired cross section or structure. Subarea surface runoff hydrographs are developed from storm rainfall using a dimensionless unit hydrograph, drainage areas, times of concentration, and SCS runoff curve numbers. Instructions to develop, route, add, store, divert, or divide hydrographs are established to convey floodwater from the headwaters to the watershed outlet. Reach routing is by a coefficient (Modified Att-Kin) method with a typical cross section stage - discharge-area curve representing a reach. Reservoir routing is by the storage indication method. In one continuous operation, the program can route through 99 reservoirs and 200 stream reaches using 9 rainfall distributions.