Youghiogheny scan to detect mine drainage
The scan is to be taken in the fall from a helicopter flying 100 feet over the river for the 46 miles from Connellsville to McKeesport.
Technicians will be able to direct electromagnetic waves as deep as 300 feet into formations under the riverbed. Five different frequencies will be used to measure five different depths for a clearer picture of the pollution.
The flight over the river is being funded by a $100,000 grant awarded last week through the state Department of Environmental Protection's Growing Greener program.
The study is headed by Terry Ackman, clean water team leader at the Department of Energy's National Technology Laboratory, located in Bruceton in the South Hills of Allegheny County.
And it has been supported by a wide-ranging coalition, including state environmental officials, county conservation districts and the grassroots Yough River Council.
The Penns Corner Resource Conservation and Development Area - an agency made up of representatives from nine southwestern Pennsylvania counties and affiliated with the U.S. Department of Agriculture - was the official grant applicant.
'(The scan) will save 20 years in determining what's going on in the river,' says Pat Trimble, mayor of Dawson and chairman of the Yough River Council.
The DOE had funded a higher-altitude thermal scan in 1999 that looked for hot spots in river. That flight showed clearly visible thermal plumes, indicating acid mine drainage.
Numerous mines were developed near the banks on both sides of the Youghiogheny River during the heyday of the coal and coke era in the early 20th century. A number of these mines also included tunnels that extended underneath the river. Drainage from the long-abandoned mines is now the source of pollution.
Overlaying old maps of the abandoned mines on the thermal scans pinpointed where much of the drainage is bubbling into the waterway.
But the flight data and overlays couldn't provide detailed information of what lies beneath the riverbed.
While the thermal scan showed where mine drainage flows into the waterway, the new electromagnetic scan will go one step further and show where fresh water dips into contaminated mine voids under the river.
By grouting fissures in the river bed it might be possible to prevent fresh water from flowing into the mine voids. Polyurethane, similar to the expandable material used for insulation around doors and windows, could be used to close off the cracks.
Preventing the flow from becoming contaminated would be easier than treating it afterward, proponents of the idea point out.
Reducing the flow required to dilute the acid mine drainage to an acceptable level would also reduce the amount of water needed to be released from the Yough River reservoir dam, Ackman noted.
Trimble said officials in West Virginia are already experimenting with grouting cracks in the beds of waterways.
Finding all the fissures in the riverbed would be prohibitively expensive at ground level. Once the electromagnetic scan is completed, Ackman said it would be added to layers upon layers of information in a computer database already collected on the river.
The electromagnetic scan of the Youghiogheny isn't scheduled until the late fall. Ackman said he would like to coordinate it with a proposed flyover of Kettle Creek in central Pennsylvania, which also has been affected by acid mine drainage.
While the technology has been used to search for mineral deposits, Ackman said the planned electromagnetic scan of the Yough may be the first time it will be adapted to find sources of pollution in a waterway.