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Dam and Levee Break Modeling Mapping and Consequence Assessment

Dam and levee failure models help USACE assess risk and enhance decision making in the event of floods and storms.
  • The team evaluated 29 dams and levees, including the East Sidney Dam in New York - Gannett Fleming

    The team evaluated 29 dams and levees, including the East Sidney Dam in New York.

Client
U.S. Army Corps of Engineers, Vicksburg District

Partner(s)
Joint Venture with WEST Consultants

Location
29 locations across the U.S.

Our Role
Modeling, Mapping, Consequence Analyses.

Data
Completed
In Progress
Duration
In Progress
Outcomes
  • Consequence models used to mitigate damage likely to occur from a dam failure
  • Information to assist in flood prevention and mitigation strategies
  • Support to make more-informed infrastructure funding decisions.

Dam and levee failure places populations at risk. However, the latest technology tools can be applied to help decision makers evaluate the contingencies and make more insightful dam safety decisions. Geographic information system (GIS) and other technology were part of a $1.6 million dam failure analysis project for the U.S. Army Corps of Engineers (USACE) Vicksburg District. The USACE assists communities in developing responses to flood risks and hazards, enhancing public safety, and developing emergency actions. 

As part of the USACE Critical Infrastructure Protection and Resilience, Dam Safety and Levee Safety programs, the WEST Consultants-Gannett Fleming Joint Venture (JV) performed GIS based hydrologic & hydraulic (H&H) analyses, consequence assessments, and inundation mapping for 29 dams and levees across the U.S. The USACE used the assessments for effective flood prevention and mitigation planning, forecasting, and preparation.

What We Did

We compiled LiDAR digital terrain data, GIS layers, and historic H&H analyses to perform hydraulic analyses and assess the potential failure mode for the dam or levee. Then, we used HEC-GeoRAS—a set of tools designed to process geospatial data—along with in-house custom GIS tools, to develop HEC-RAS models of more than 1,500 river miles. Additionally, using HEC-FIA, a flood-impact analysis software, we performed consequence assessments based on the results of the dam and levee break scenarios. 

To visualize potential downstream consequences from a dam failure, along with impacted critical infrastructure, we developed inundation mapping products within a GIS environment, covering more than 30,000 square miles.  Also, we designed an automated workflow that included a suite of custom GIS tools to facilitate the development of a river channel bathymetric surface, which would provide more accurate hydraulic models and reduce model development costs. For 3-D visualization, we developed a toolbar to work interactively inside of ArcMap with 3-D line layers and terrain surfaces.  

Key Features

  • The dam failure analyses were simulated under five hydrologic loading conditions 
  • More than 40,000 structures downstream of the various dams were analyzed for potential impacts from the modeled scenarios
  • Gannett Fleming developed custom GIS tools to support modeling and mapping activities, including special mapping algorithms to delineate and cleanup flood boundaries delineated with HEC-GeoRAS
  • As a companion to the USACE’s existing Dam Failure Modeling standard operating procedures (SOP), the JV developed an SOP for levee modeling that will be the future standard for MMC levee breaching analysis and mapping
  • Custom ArcGIS tools were developed to expedite hydraulic model development, digital terrain modeling, and inundation mapping.

Sustainability Features & Outcomes

  • Reduces risks to the public from dam and levee failure 
  • Information to assist in land use planning
  • Helps to perverse water supplies for hydropower, drinking water, fish and wildlife conservation, and recreation 
  • Leads to better flood prevention and emergency planning, thereby safeguarding infrastructure.

Similar Projects: Dams & Levees: Dam Risk & Reliability Assessments, Water/Wastewater: Dams & Levees, Dams & Levees: Emergency Action Plans & EAP Exercises, Engineering, Federal, Dams & Levees: Flood Hazard & Risk Assessment, Information Technology: Geospatial, Information Technology, Dams & Levees: Levees, Dams & Levees: Planning, Federal: Water Resources, Water/Wastewater