Sunday’s severe rain storms dumped nearly two inches of rain in the area, saturating the ground and along with an additional 2.4 inches of rain during the past 48 hours. The heavy downpour caused flooding in local streams and at the County’s largest water treatment facility.
The Mattawoman Water Reclamation Facility, a 20 million gallon/day (mgd) facility, received 42 mgd during the same period it normally treats 12.5 mgd. Increasing flows necessitated staff taking the ultra-violet (UV) process used for disinfection out of service temporarily to prevent damage that would have taken it out of service for an extended period of time.
A portable pump was set up to convey some of the fully treated, but not disinfected flow into an adjacent stream that flows into Mattawoman Creek; effluent from the plant is normally pumped out into the Potomac River. This was done to quickly bring the UV process back on-line and to prevent additional damage to equipment at the facility.
The UV process was out of service between 7:45 and 11:15 p.m. Thursday night; effluent from the facility, though fully treated and diluted with 70% rainwater, was not disinfected during this time. Samples of the stream were taken both up and down stream of the discharge for analysis. A portion of the flows, which are now fully treated, are still being diverted to the stream to prevent further equipment failures until the flows are reduced to a safe level. A recreational fishing area immediately downstream of the facility has signage posted advising citizens to avoid contact until stream flows return to normal.
All area streams have been impacted by these rain events and have swelled well outside of their normal banks. Rainfall amounts of this magnitude wash many pollutants from ground surfaces into these waters; this creates the potential for health hazards to those coming in contact with the water. Governor O’Malley declared a State of Emergency due to the impacts of these storms.
The Charles County Department of Public Works and the Charles County Department of Environmental Health are strongly advising citizens to avoid contact with these waters until stream flows return to their normal levels. This includes all types of recreational contact and taking or consuming fish caught during this time. As a reminder, the Maryland Department of Environment closes all shellfish harvesting down for at least 48 hours following a rain event of more than one inch. Please contact the Health Department or the Department of Public Works for more information.
