Power Station Background
Since 1995, groundwater seeps into two local streams has been noted at a power station in eastern Pennsylvania. During sampling, elevated levels of iron had been detected, suggesting an acid mine drainage (AMD) condition. In addition, ash-related constituents had also been detected in bedrock groundwater in the area, which were believed to be associated with a nearby retired ash basin. In 2008, the Pennsylvania Department of Environmental Protection (PADEP-Harrisburg Office) requested that the client perform an assessment of groundwater flow and quality in the area to better evaluate the situation.
Groundwater Assessment Project Work
For this project, AGES was subcontracted by a nationally recognized expert, who was under contract to the client. Prior to preparing a groundwater assessment plan, staff from AGES along with the expert, met with representatives of the PADEP (Harrisburg Office) in the field to discuss the approach to the project. Based on the meeting, the objectives of the project were to:
1.) Design and install shallow piezometers to define the groundwater flow field and to obtain water quality data to identify potential sources of possible AMD;
2.) Design and install monitoring wells in the shallow bedrock material to evaluate groundwater quality and flow with respect to the migration of ash-related constituents from a nearby retired ash basin; and
3.) Analyze and evaluate the data obtained from field work to delineate the source(s) of AMD and ash-related constituents.
After the meeting, AGES developed a groundwater assessment plan for the project. The plan was submitted to PADEP and was approved with only minor comments. The field investigation included the installation of 18 piezometers and three (3) bedrock wells, development and hydraulic testing of the piezometers and wells, and two (2) rounds of groundwater sampling.
Based on the results of the investigation, AGES determined that the shallow groundwater flow field in the area was very stable with minimal fluctuation. Shallow groundwater chemical conditions at the site were also fairly stable, with no evidence of AMD-like conditions being observed. Finally, ash-related constituents were not detected in shallow bedrock groundwater. AGES and the expert submitted a report to the PADEP with these results; PADEP is not requiring any further action in the area.
Special Features
1.) Negotiated with the PADEP (Harrisburg Office) on the scope of work and approach to the project.
2.) Prepared a groundwater assessment plan that was reviewed and approved by the PADEP (Harrisburg Office).
3.) Successfully implemented the plan and developed recommendations that allowed for no further action at the site.
