COAL RUN

The Problem: The Coal Run discharges are located in South Fayette Township and are about 0.7 miles southwest of the McLaughlin Run discharge and 0.3 mile south of the Bridgeville exit on Washington Ave. Unlike any other discharge, this one emerges from the within the streambed of Coal Run, just 100 feet upstream from the Rt 50/Washington Ave crossing. One discharge is several inches above stream flow at base flow, but quickly is submerged with any runoff. Its reported flow is 910 gpm, but this is not an isolated discharge, like the others, which are measured by flumes, weirs and pipes. It is the discharge-laden stream-flow. 

Nonetheless the iron loading ranks third at 158 kg/day, higher than its closest cousin, Wingfield Pines (114), which lies several hundred yards upstream and across Chartiers Creek. It fouls about 0.2 miles of Coal Run before joining Chartiers. The alkalinity concentrations, 350-450 mg/L are very high values for AMD. Since it was measured during Operation Scarlift (1960's), its flow and iron have been cut in half. It has also become substantially more alkaline. 

The Solution:  Collect the discharges, pipe across Chartiers Creek, and treat with passive system.  However, the discharges are within creekbeds, making treatment design costly and difficult. Land between the discharges and Chartiers Creek is valuable commercial property, making adequate area for passive treatment problematic. With the Wingfield Pines project, iron levels should be below in-stream standard through this segment and Chartiers Creek can better assimilate discharges from Coal Run. Although the discharges are very visible, impact is low, so the interim solution at this time may be to do nothing.

Coal Run was mined in the first decade of the 1900s. Unfortunately the existing maps do not show the full extent of mining, so that the extent of the recharge area and potential mine pool cannot be determined.  Treatment of the discharges is a low priority because of the small impact on Chartiers Creek, because of difficulty collecting discharges and moving to system location, and because ALT's Wingfield project will substantially improve the Upper Segment. 

PRESTO-SYGAN

The Problem: Presto-Sygan discharge is located in South Fayette Township on the west side of Chartiers. It flows from an old stone structure and flow is measured with a flume 30 feet away. The flow ranks 4th. Unlike the other discharges it has the highest amount of aluminum (aluminum hydroxide solids). At 12.9 mg/L with an obvious milky white sediment and turbidity, it has almost four times the aluminum of the second highest other aluminum discharge (McLaughlin). It has the third highest acid loading. Compared to the other discharges, it has the most variable flow and chemistry. 

Comparing these findings with those of Operation Scarlift of forty years ago, it had twice the acidity and two-thirds greater flow. There are many mines that drain to this point giving it the second highest recharge area at 3400 acres, but with the flow measures, the average recharge is comparatively low at .12 gpm/acre. Mine drainage originates near Oakdale at an elevation of 1020 and the discharge is at 830. A large pool would be expected to cover about 200 acres with the top of it at the discharge elevation (830). 

There may be two other pools within the mine complex and almost 2 miles northwest of the discharge pool. One of these pools may discharge to Thoms Run during high flow conditions. A large pipe is located there, but on one visit was not discharging. There is evidence of mine drainage with orange staining which should be monitored in the future. 

The Solution:  PA DEP awarded a $48,000 Growing Greener grant to South Fayette Township to design a  passive treatment system for a 400 gpm discharge to Chartiers Creek.  Work will be performed by Stream Restoration, Inc.