Upper Potomac River Commission Wins Dam Safety Award
Successful Replacement of Gates that Control Releases from Savage River Reservoir
(RALEIGH, NC – August, 9, 2010) Hazen and Sawyer and the Upper Potomac River Commission (UPRC) have been awarded the 2010 Association of State Dam Safety Official’s Northeast Regional Award of Merit for development and execution of a successful plan to replace the four gates that control releases from the Savage River Reservoir. The Association gives this award annually to individuals or organizations working in the dam safety field that have made outstanding contributions to dam safety on a regional level.
The Savage River Dam is a 180-foot high earth and rockfill dam which impounds a 17,400 acre-foot reservoir in western Maryland. It is classified by the State of Maryland as a High Hazard structure due to the potential for serious damage and probable loss of life in the event of a dam breach. Operated under guidance provided by the U.S. Army Corps of Engineers, the project was constructed in 1952 primarily for flood control and low-flow augmentation in and downstream of the Savage River, a prized native trout stream located on the North Branch of the Potomac River. It is also the source of about 20 percent of the Potomac water used by three major utilities serving the greater District of Columbia area.
Controlled releases from the reservoir are made through four heavy steel gates, two service gates and two emergency gates. In December 2007, the Right Emergency Gate failed to operate and was stuck in the closed position, rendering half of the outlet works inoperable. An engineering investigation found extensive internal corrosion in both of the emergency gates. This damage was hidden from view by the double-skin case steel construction of the gates. The study determined that the gates were at risk of structural failure under high reservoir levels and recommended that all four gates be replaced.
The State of Maryland and the UPRC entered into a Consent Order to address the impaired condition of the existing gates. Under the impetus of this order and with concern for public safety, the UPRC and Hazen and Sawyer developed a plan to maximize the prospects for the completion of the gate replacement project during the 2009-10 late fall-winter months (the only time of year when it is feasible drain the reservoir as required to replace the gates), and for funding as a “shovel-ready” project under the then-pending American Recovery and Reinvestment Act (ARRA).
This proved to be a successful strategy. The project was approved for funding under the ARRA program in time to allow construction to be advertised in July 2009. The gate installation was successfully completed in April 2010.
However, ARRA funding delays narrowed the critical window available for draining the reservoir and installing the new gates in time for re-impounding of the reservoir prior to the onset of the spring snowmelt. Following heavy snowfall in February 2010 and subsequent forecasts for a heavy snowmelt, the UPRC and Allegany County authorized the contractor to accelerate the work in order to complete the critical gate installation sequence prior to the anticipated snowmelt. Working double shifts, the Contractor completed the critical sequence in time to commence re-impoundment on the evening of March 5, 2010, when flow through the reservoir’s outlet tunnel was about 50 cubic feet per second (cfs). By March 8th, tunnel flow had increased to 200 cfs, which would have curtailed further work had the critical gate installation sequence not been completed. On March 13th the reservoir completely refilled, with reservoir inflow peaking at over 7,000 cfs.
Since our founding in 1951, Hazen and Sawyer has focused on two things: providing safe drinking water and controlling water pollution. Our range of services encompasses the planning, design, and construction management of water and wastewater-related projects – from clean water treatment, storage, and distribution to wastewater and stormwater collection, treatment, and reuse.