Occoquan River Dam safety alert sirens to be tested Dec. 13

Residents of the Town of Occoquan and other Prince William and Fairfax residents who live near the Occoquan River will hear siren blasts Thursday at 10 a.m. as Fairfax County Water Authority tests the new sirens it has installed.

The new Occoquan River dam sirens are a warning system is designed to alert residents and businesses downstream in the event of a catastrophic failure of the Occoquan River Dam.  Although the dam is structurally sound and deemed very safe by authorities, the Federal Energy Regulatory Commission recommended the safety alert system and the Town of Occoquan supported the water authority’s siren plan.

At the request of the Town of Occoquan, Congressman Gerry Connolly secured $25,000 in federal funding in fiscal year 2010 as seed money for the project. The remaining cost was borne by the water authority.  The Occoquan River Dam is located approximately one mile upstream from the Town of Occoquan.

Although a serious dam breach is unlikely, the new warning system provides an additional element of safety for the citizens of Occoquan and other residents along the river,” Connolly was quoted as saying in a news release. “In the event of a failure, these sirens can save lives and afford residents in communities like the Town of Occoquan and Belmont Bay time to seek safe shelter.”

Studies show that in the event of a catastrophic dam failure, the first wave of water would reach the Town of Occoquan in 5 to 10 minutes and it would cover most of the town’s historic district in 54-foot-deep water within 20 minutes, depending upon preexisting ground saturation.

Residents and businesses in the impact zone have received a post card in the mail informing them of Thursday morning’s test of the sirens.  More information about the siren and the Dec. 13 test can be found at http://www.occoquandamsiren.com.

According to a statement from the Fairfax County Water Authority, “The structural integrity of the Occoquan Dam is very sound. In fact, through rigorous maintenance and improvements, it is even stronger today than when it was constructed. The dam is approximately 72 feet tall and 70 feet wide at its widest point. It is anchored to the bedrock below the bottom of the dam and to the sides of the reservoir.  It contains more than 100,000 cubic yards of reinforced concrete.”