Flood Control Studies

DEA provides single beam hydrographic surveys, water level observations and Acoustic Doppler Current Profiler (ADCP) flow measurements for flood stage analysis.

DEA runs annual cross-section surveys on the Cowlitz River to monitor sediment transport from Mt. St. Helens runoff. Our cross-section surveys have supported flood analysis of the Willamette Valley, Snake River and the Columbia Basin extending from the Pacific into Idaho and Montana. Detailed surveys of bridges are conducted to document restrictions for model input. Data is organized and compiled for direct entry into US Army Corps of Engineers (USACE) HEC-RAS. Each cross-section is photo documented and a geodatabase of photos is provided to aid modelers with roughness coefficient determinations.