Multiple-regression techniques are commonly used to transfer flood characteristics from gaged to ungaged watersheds. In the arid or semiarid areas of the united states, the standard errors of these regression relations often are quite large. One way to reduce the standard error is to identify basin characteristics that are significant for predicting t-year flood discharges such as 50- or 100-year floods. Recent investigations have identified new characteristics that appear to be promising. Examples of these are main channel sinuosity, hydraulic radius, bank-full channel conveyance, basin shape, time-to-peak of the flood hydrograph, effective drainage area, and percent of the basin in a given hydrologic soil group. The appropriateness of their use and the application of these basin characteristics are discussed. In addition, a few new basin characteristics are suggested that have not yet been investigated. Examples include channel infiltration losses, ratio of main channel width to flood-plain width, stream-network magnitude, channel storage indices, and drainage density.
Abstract