Channel responses to artificial stream capture, Death Valley, California

Abstract

Artificial capture of Furnace Creek Wash by Gower Gulch in 1941 caused channel responses in three separate reaches of this integrated ephemeral stream system: (1) upper Furnace Creek Wash, (2) Gower Gulch channel, and (3) Gower Gulch fan. At the diversion point, vertical erosion had lowered the brink of a 25-m nickpoint by approximately 3.2 m by 1974. Upstream from the nickpoint, Furnace Creek Wash had responded with headward dissection for 2.7 km and removal of debris at a mean rate of about 4 × 10^3 m^3/yr. The mean slope of the Gower Gulch channel had been lowered throughout by erosion due to drastically increased discharge, producing debris at a mean rate of about 2 × 10^3 m^3/yr. Dissection of the upper part of the Gower fan to a maximum depth of 5.7 m and production of debris at a mean rate of about 0.4 × 10^3m^3/yr are attributed to high stream velocities and increased discharge. In the absence of further intervention, evolution of the system during the next few hundred years is likely to be characterized by the following: (1) increasing depth and extent of headward dissection in Furnace Creek Wash and its tributaries upstream from the diversion point and (2) readjustment of the Gower fan profile in response to accumulation of coarse diverted debris.

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