On Saturday, August 22, 2009, at approximately 4:00 p.m., the sewage pump stations at Austin Run (2602 Jefferson Davis Highway) and Potomac Hills (1320 Kingcrest Drive) overflowed due to lightning strikes that disabled the flow transducers at both stations. The transducers control the pumps that move the effluent from the wells to the Aquia treatment center.  

The Austin Run station overflowed approximately 2.5 million gallons into Austin Run and Aquia Creek. The Potomac Hills station overflowed approximately 55,000 gallons, also into Aquia Creek.  The sewage from both stations has been washed downstream due to the rapid flow of water caused by the heavy thunderstorm on Saturday.

The overflow volumes are much higher than normal because the telemetry system for these two stations malfunctioned and did not trigger the station alarms, as they are designed to do during an overflow. The telemetry system monitors flows at the sewage pump stations.

Because the alarms did not activate, Utilities plant operators were unaware of the overflows when they occurred. The overflows were not discovered until Utilities mechanics rebooted the telemetry system at 7 a.m. today, Monday, August 24, after their routine inspection of the telemetry system.

The stations have been repaired and are now operating normally. Staff is also working with the telemetry contractor to determine how to prevent the malfunction from recurring. In addition, staff has spread lime to disinfect the area of the spill.  

The overflows were reported to the Virginia Departmental of Environmental Quality (DEQ) this morning. A written follow-up will be sent to DEQ this week. The Health Department was also notified this afternoon. Staff has notified the Aquia Harbour Homeowners Association because some homeowners have property that abut Aquia Creek.

It is difficult to determine whether the overflows affected bacteria levels in Aquia Creek because it is considered an urban stream, and bacteria levels are always present in an urban stream. In addition, they become elevated after a thunderstorm.