HR: 0800h
AN: H31B-0358    [Abstracts]
TI: Volume and Flood Frequency Characteristics of Ephemeral Streams in the Semi-arid U.S.
AU: * Makowski, A
EM: anna.makowski@dri.edu
AF: Desert Research Institute Division of Hydrologic Sciences, 2215 Raggio Parkway, Reno, NV 89512, United States
AU: Schumer, R
EM: rina.schumer@dri.edu
AF: Desert Research Institute Division of Hydrologic Sciences, 2215 Raggio Parkway, Reno, NV 89512, United States
AU: Boyle, D P
EM: doug.boyle@dri.edu
AF: Desert Research Institute Division of Hydrologic Sciences, 2215 Raggio Parkway, Reno, NV 89512, United States
AB: Large runoff events in the arid and semi-arid regions of the U.S. are generally a result of intense, short-duration (less than 24 hours) precipitation events and frequently result in considerable property damage and loss of life. Urban flood mitigation and channel restoration projects in these areas currently depend on short duration volume frequency relationships derived from precipitation characteristics in the course of performing rainfall-runoff analyses, rather than directly from observed streamflow data as is standard practice for longer durations (>1- day). Until recently, only average daily flows were reported for USGS stream gauges so hydrograph characteristics could not be used to assess rainfall-runoff models or evaluate whether mitigation structures were meeting design specifications. Archived high-temporal resolution streamflow records for 14 uncontrolled ephemeral streams in the Las Vegas region were digitized so that hydrograph characteristics (peak, shape, volume) could be measured. Where possible, flood frequency and volume-frequency-duration analyses were performed for the ephemeral streams. These analyses demonstrate the importance of using partial duration series rather than annual maxima for frequency analyses as well as the significance of using maximum daily flow rather than average daily flow when assessing the hazards posed by ephemeral streams.
DE: 1815 Erosion
DE: 1817 Extreme events
DE: 1821 Floods
SC: Hydrology [H]
MN: 2007 Fall Meeting