George’s Creek - McDonald Mine Seep
Prepared by Ken Pavol

A quality trout fishery, with plenty of large trout, existed in the North Branch downstream of Westernport beginning around 2001. The trout population was supported primarily through a DNR fingerling trout stocking program, but a number of wild brown trout were also present. The fishery changed sometime after mid-summer in 2005, co-incident with a severe acid mine drainage pollution problem that developed in George’s Creek at the site of the “McDonald seep”.  Up until that time, the McDonald seep was being effectively treated with a small lime doser deployed and maintained by the Bureau of Mines.  A put and take trout fishery, including a youth only area, was managed by DNR downstream. In one day during August 2005, water quality from the McDonald seep deteriorated. Acidity increased by a factor of 10 while flow volume increased to three times the prior volume; in an AMD source that was already producing the worst water quality in an AMD source in Maryland according to MDE.

All fish died in the 4 miles of George’s Creek downstream to the North Branch in a very short time.  Later, a rain event increased flow in George’s Creek to several hundred cfs, while the Army COE withheld water at Jennings Randolph and the Savage River Dams. The relatively undiluted pollution from George’s Creek traveled down the North Branch, leaving evidence of the presence of toxic aluminum in the form of white deposits on rocks for miles downstream.  The high quality trout fishery in the North Branch downstream of George’s Creek virtually disappeared and has only partially recovered.

An adequate lime doser and the capture and removal of metal precipitates from the pollution site are required to address the problem. The technology exists but adequate funding is lacking.  The efficiency of the lime dosing effort at the McDonald seep has been increased and pH in George’s Creek is improved.

     Although water chemistry is improved by lime dosing at the site, the problem of metal deposition in George’s Creek remains. Many tons of precipitated iron is generated as pH is increased through lime dosing. The metals, which are in solution, precipitate as pH is increased above about 4.5.  Under low flow conditions, most of the iron precipitate is deposited on the substrate of George’s Creek, smothering the invertebrate community. During rain events when flow increases, the metal precipitate is mobilized and flows downstream in a wave of extremely turbid water, eventually entering and impacting the North Branch Potomac.  Fish life in George’s Creek is essentially eliminated through a combination of the lack of a forage base and interference with gill function by the heavy sediment load. A few fish occupy the stream near its confluence with the North Branch under low flow conditions when George’s Creek is less turbid. Although progress has been made in terms of improved water chemistry, the huge metal loading persists with no real solution or commitment by MDE to address the problem in sight.

           The MAC initiated contact with MDE urging a commitment to effectively address the AMD pollution issue at the McDonald seep on George’s Creek. Although MDE has responded, they have not yet committed to an overall strategy that will address all aspects of the problem.