Lake Montclair Property Owners Association owns Montclair dam, a 74 foot tall High Hazard earthen dam on Powells Creek in Prince William County, Virginia. The dam was constructed as a recreational and aesthetic lake for the HOA. The Virginia Department of Conservation and Recreation Office of Dam Safety required that an inundation Study and Spillway Stability Analysis be completed as the first steps to obtain a new Regular Operating Permit.

F&R’s dam services group completed an inundation study and mapping for use in the HOA’s EAP. The Inundation Study confirmed the dam was High Hazard with no allowable spillway reduction. The existing spillway capacity was insufficient and proved to be erodible using SITES analysis of its current configuration that included a beach at the lake front and a parking lot as amenities in the spillway.

F&R performed a Preliminary Engineering Report (PER) with several options. The MPOA selected a concrete cutback protection wall and an increased spillway flow area to meet the required capacity and allowed retention of the amenities.

F&R designed the spillway and managed its construction. The Dam Safety project was completed and the dam received a new Regular Operating Permit.

For our efforts assisting the Shirley Contracting team, F&R was awarded the HCCA’s Excellence in Infrastructure Award.