Geomorphologic characteristics and instantaneous unit hydrographs of Indiana watersheds
Abstract
Ten basins in Indiana were selected to study their geomorphologic properties, fractal characteristics and geomorphologic instantaneous unit hydrographs (GIUHs). Horton's laws of stream network were found to be valid for these basins. Drainage maps of these basins were delineated manually and by using two digital elevation models (DEMs). Except for regions where elevation data are unreliable, geomorphologic properties of automatically derived and manually delineated drainage basins are similar. Feder (1988) and Rosso et al. (1991) formulas were used to compute fractal dimensions of the main stream length of the basins. The computed fractal dimensions were found to be comparable to the measured fractal dimensions. The method of Mesa and Gupta (1987) to compute main stream length was modified to be applicable to basins with more than one major channel. Discharge and energy fluxes in the study watersheds were found to follow power law distributions. Exponents of the resulting power laws do not show the universality suggested by Rodriguez-Iturbe et al. (1992). The performance of three GIUH models was evaluated by using them to simulate runoff hydrographs from the study basins. For all of these models, peak flow and time to peak were found to be sensitive to the value of the streamflow velocity. The streamflow velocities of the three models were found to be correlated. A new method of estimating the non-measurable parameters of these models was developed. In this method, parameters were estimated as a function of rainfall and geomorphologic properties of the basin.
Degree
Ph.D.
Advisors
Rao, Purdue University.
Subject Area
Civil engineering|Mechanical engineering
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