HR: 1330h
AN: H42C-1092    [PDF]
TI: Predicting Channel Evolution and Sediment and Contaminant Transport Following the Cerro Grande Fire, New Mexico
AU: * Wilson, C J
EM: cjw@lanl.gov
AF: Los Alamos National Laboratory, EES-2 MS J495, Los Alamos, NM 87545
AU: Canfield, H E
EM: ecanfield@tucson.ars.ag.gov
AF: USDA-ARS, 2000 E. Allen Rd, Tucson, AZ 85719
AU: Crowell, K J
EM: Crowell@lanl.gov
AF: Los Alamos National Laboratory, EES-2 MS J495, Los Alamos, NM 87545
AU: Lane, L J
EM: ljlane2@msn.com
AF: Los Alamos National Laboratory, EES-2 MS J495, Los Alamos, NM 87545
AB: The May 2000 Cerro Grande Fire severely burned the headwaters of many of the canyon streams draining through the Los Alamos National Laboratory (LANL), Los Alamos County and Pueblos in Northern New Mexico. The fire increased observed flood magnitudes and hillslope erosion rates by one to two orders of magnitude above pre-fire conditions. A set of modeling activities was undertaken to predict the potential impacts of post-fire floods on channel and floodplain evolution, and sediment and contaminant transport in the steep streams draining the burn area. A contaminant transport model, Reach6, was developed and coupled to the HEC6T sediment transport model to predict redistribution and offsite transport of contaminated channel and floodplain sediments. Model predictions were tested against observed flood data. In particular, the HEC6T predictions were tested against high-resolution Airborne Laser Swath Mapping (ALSM) topographic data, collected before and after a 1440 cfs flash flood in a canyon contaminated with low levels of legacy Pu. The ALSM data showed the spatial distribution of channel and floodplain scour and deposition throughout the canyon. These data formed the backbone of our model testing process, along with observed sediment and Pu concentration data. Good correlation was found between predicted and observed data for the 1440cfs event, and led to application of the HEC6T model in assessing the effectiveness of remediation and stabilization strategies for Pueblo Canyon. LANL LA-UR-03-6382.
DE: 1815 Erosion and sedimentation
DE: 1821 Floods
DE: 1824 Geomorphology (1625)
DE: 1871 Surface water quality
SC: Hydrology [H]
MN: 2003 Fall Meeting