“This, in my opinion, provides a great opportunity not only to help sustain the performance of a system, but also to encourage and recognize the efforts of the watershed group and their partners,” said Margaret Dunn, Stream Restoration, Inc., a non-profit watershed restoration group.
To highlight the importance of ongoing maintenance of passive treatment system, here is the first of what will be several case studies, this one in Armstrong County.
O&M Effort At The Decade-Old NuMine-White Lake Passive Treatment System
The Cowanshannock Creek Watershed Association (CCWA) recently received support to rehabilitate the NuMine-White Lake Passive Treatment System in Cowanshannock Township, Armstrong County.
Continuing the treatment effort at this site is important, as the passive system has enabled White Lake to sustain good quality water with a 6 to 7 pH that contains typically less than ½ mg/L each of iron, manganese, and aluminum.
The site has also historically been instrumental in providing knowledge about passive treatment technology as federal and state agencies have not only conducted research but also contributed to the treatment effort at the site.
For instance, the first passive component, an aerobic wetland, was installed in about 1988 by what is now the Natural Resources Conservation Service with some of the early “groundbreaking” research efforts conducted by the former US Bureau of Mines.
In 2002, the DEP’s Bureau of Abandoned Mine Reclamation (BAMR) placed additional components online. Since that time, the CCWA has been overseeing the system performance and hosting educational field trips at the site for students from the local high school.
Based on available monitoring data, the AMD entering the expanded system typically has a pH of 4 with 15 mg/L of aluminum and relatively low iron and manganese content. After about a decade of changing this acidic drainage to net alkaline water containing only about 1 mg/L of aluminum, the limestone-only vertical flow pond became plugged by aluminum solids and other sediment.
Anne Daymut of the Western PA Coalition for Abandoned Mine Reclamation and member of the watershed association, requested support to rehabilitate the system through the O & M Technical Assistance Program made possible by grants from the DEP Growing Greener Program and the Foundation for Pennsylvania Watersheds and by volunteer efforts.
Through these partnership efforts, in September 2012, the limestone aggregate was washed to remove aluminum solids and other sediment, which was then captured in pumped-water filter bags or the existing sediment pond.
In addition, a new upper level layer of underdrain pipes was re-installed to allow for faster drainage during the monthly system inspection conducted by the CCWA. Pam Meade, John Bohonak, and others from the CCWA were onsite regularly to assist with the renovation.
The CCWA also wishes to express their appreciation for the support of the Armstrong Conservation District and the USDA NRCS throughout the years.
Information about the system including water monitoring will be uploaded, when available, to Datashed.org.
Requesting Maintenance Assistance
For watershed groups interested in participating in the O&M Technical Assistance Program, please contact Stream Restoration Inc. by sending email to: sri@streamrestorationinc.org.