Recent rainfall has led to at least 2 feet of water flowing over the spillway of the Carvins Cove Dam in Roanoke County.
The Western Virginia Water Authority, which owns the dam, has notified local Emergency Services Coordinators and the National Weather service after issuing a Stage II notification.
What this means is that 2 feet of water over the spillway is a trigger point in the authority’s emergency action plan. It is
an indicator of imminent dam failure, according to WVWA.
Stage II was also reached in late May following heavy rainfall.
The authority wants everyone to be aware that the notification is something they are required to send out. A 2014 study determined the dam would not fail until it reached 14 feet of water over the spillway.
The 80-foot tall dam has a 112-foot wide spillway and impounds 6.42 billion gallons of water at full pond, according to the authority. Water exceeding that capacity goes over the spillway into Carvins Creek.
The WVWA revised its emergency plan for the dam in December 29, including three levels of emergency notification.
According to the authority:
“Stage I is noted when there is not an emergency, failure is unlikely and storm developments are slow in escalation to a potential emergency. The stage indicates a situation is developing such that the dam is not in danger of failing, but if it continues, a failure may be possible.
“Stage II is utilized when potential failure or storm development are quickly accelerating that could result in failure of the dam. 2 feet of water flowing over the spillway is also an initiator of Stage II.
“Stage III indicates an imminent failure or a storm that has reached a point that the failure of the dam has started or is imminent. This stage indicates dam failure is expected or occurring and may result in flooding that will threaten life and/or property downstream of the dam.”
The authority says it will continue to closely monitor the reservoir level, spillway flow and forecasted precipitation and notify emergency personnel and residents of any changes. Stage III is not expected to be reached.