• ARWA Sludge Lagoon Dam
  • Brookneal Reservoir Dam
  • Bedford Lake Dam
  • Red Hill Quarry Dam
  • Wildwood Recreation Dam No. 1
  • Brushy Mountain Club Dam
  • South Wales Country Club Dam
  • Wheeler’s Pond Dam
  • Farmwell Hunt Dam

Dam safety

WW Associates personnel have extensive knowledge concerning the recent modifications to the Virginia Dam Safety Regulations.  These modifications include the following regulations:

  • Dam Break Inundation Map – 4VAC50-20-40 (Hazard Potential Classification of Impounding Structures)
  • 4VAC50-20-175 (Emergency Action Plan for High and Significant Potential Hazard Impounding Structures)
  • 4VAC50-20-177 (Emergency Preparedness Plan for Low Hazard Potential Impounding Structures)

Our personnel start with an initial watershed assessment both upstream and downstream of an impoundment structure to collect field data required for hydraulic analysis and flood routing.  Dam break analyses are performed using Department of Conservation and Recreation (DCR) approved HEC-RAS modeling software, evaluating both non-breach and breach discharge scenarios.  The following dam breach scenarios are modeled as a minimum:

  • Sunny day dam break with the starting water surface elevation at the normal water surface elevation of the impounding structure.
  • Dam failure during the required spillway design flood.  An overtopping failure is modeled if the emergency spillway is unable to pass the spillway design flood without overtopping the crest of the dam.  A piping failure is modeled if the emergency spillway has enough capacity to pass the required spillway design flood without overtopping the crest of the dam.
  • Routing the spillway design flood through the dam without any failure.
  • Dam failure during the Probable Maximum Flood

We use the HEC-RAS software to develop inundation limits for each of these scenarios to determine the greatest impact to structures located downstream of the dam.  Based on the results of the model analysis, we develop a Hazard Classification for the dam, establish its required Spillway Design Flood (SDF), and perform an Incremental Damage Analysis (IDA) in accordance with the Dam Safety Regulations.  This information is compiled into an Inundation Report summarizing our findings and subsequently submitted to DCR to demonstrate regulatory compliance on the part of the Owner.