HYDROLOGIC ROUTING OF FLOW IN ARID EPHEMERAL CHANNELS

Abstract

Hydrographs of ephemeral streams in an arid region usually decrease significantly in magnitude, downstream I unless they are augmented by tributary flows. Estimation of outflow hydrographs from a channel reach is essential for the development of water-resources systems. A hydrologic-flow-routing technique for arid ephemeral channels is developed. The hydrologic-routing equations for the movement of flood waves are modified by the inclusion of a nonlinear volumetric transmission loss rate term, which is empirically estimated from the observed inflow-outflow data for a channel reach. The predicted outflow hydrographs match better with the observed than the outflow hydrographs generated through the lumped regression model for ephemeral channels. The hydrologic-flow-routing technique may also be used for ungaged channel reaches through parameterization.