JOIN US SEARCH LOCATIONS CONTACT DEA HOME WHO WE ARE WHAT WE DO SOLUTIONS NEWS MARINE SERVICES :: FLOOD CONTROL AND RESERVOIR CAPACITY STUDIES DEA provides single-beam hydrographic surveys, water level observations, and Acoustic Doppler Current Profiler (ADCP) flow measurements for flood stage analysis. For example, DEA runs annual cross-section surveys on the Cowlitz River to monitor sediment transport from Mt. St. Helens runoff. Our cross-section surveys also have supported flood analysis of the Willamette Valley, the Snake River, and the Columbia Basin extending from the Pacific Ocean into Idaho and Montana. We conduct detailed surveys of bridges to document restrictions for model input. Data is organized and compiled for direct entry into USACE’s HEC-RAS. Each cross-section is photo-documented and a geodatabase of photos is provided to aid modelers with roughness coefficient determinations. Reservoir capacity surveys include the use of high-resolution multibeam sonar for underwater mapping and upland vessel-based laser scanning or aerial mapping for detailed modeling of reservoirs and accurate capacity curve calculations. DEA has also worked on projects that have included comparison to pre-impoundment or earlier mapping efforts for assessment of sediment migration. More Key Contacts :: Related Projects Marine Services Navigation and Nautical Charting Infrastructure Inspection Marine Design and Construction Support Flood Control and Reservoir Capacity Studies Environmental Investigations Marine Geophysical Investigations Geospatial Analysis Mobile Vessel Laser Scanning Hydrographic Surveys Marine Services Projects Who We Are History Core Ideology Leadership Stewardship Locations Contact DEA What We Do Energy Land Development Transportation Water and Environment Surveying and Geomatics Marine Services Solutions Alternative Project Delivery Construction Engineering Energy Development Engineering Landscape Architecture Environmental Planning and Compliance Planning Project Management News Awards Rankings Join Us Our People Current Openings Benefits Subconsultants and Vendors David Evans and Associates, Inc., 2100 S. River Parkway, Suite 100, Portland, OR 97201 :: 800.721.1916 Copyright © 1996-2021 David Evans and Associates, Inc. All rights reserved. :: Terms of Use | Privacy Policy