||Effects of Channel Characteristics on Time Parameters for Small Watershed Runoff Hydrographs.
Golan, Pinhas ;
Larso, Curtis L. ;
||Minnesota Univ., Minneapolis. Water Resources Research Center.
||WRRC-Bull-31; OWRR-B-007-Minn; 08121,; B-007-Minn(5)
( Watersheds ;
Surface water runoff) ;
Flood routing ;
Mathematical predictions ;
Soil structure ;
Channel flow ;
Computer programming ;
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Most, if not all, parametric methods for predicting peak runoff from small watersheds require some type of time parameter as part of the runoff routing. The effects of watershed characteristics such as length, slope and roughness of the main channel and watershed area on time parameters were investigated in this study. A mathematical model and a computer program were developed for solving the dynamic equations of continuity and momentum to route nonsteady runoff through a channel system. A theoretical equation for computing the time to virtual equilibrium (time required for the rate of runoff at the outlet to become equal to the supply rate) was derived. The results of the research indicate the relative effect of the overland flow on the time to virtual equilibrium of the watershed decreases as the watershed size increases, and vice versa. The time to virtual equilibrium decreases as the supply rate increases and the non-linearity of the runoff process is shown. (WRSIC abstract)