research project details
Project Title: AMD TMDLs and sampling for Bureau of Watershed Conservation
Investigator(s): Brian A. Dempsey
Sponsor: PA Department of Environmental Protection
Environmental Problem Addressed: nonpoint source pollution
Research Project Objectives: Dempsey will lead a team whose purpose is to develop TMDLs for Pennsylvania, including the generation of all documentation necessary for submittal of a TMDL to the U.S. Environmental Protection Agency. The team will conduct water quality sampling and analysis as appropriate to support the development of TMDLs. They will complete modeling analysis for the impaired stream segments. Specific objectives for this study include:
- Conduct a sampling and analysis program to determine seasonal flow and water quality data for ten study areas (106 sample sites) in western Pennsylvania that were affected by AMD;
- Perform TMDL calculations to determine the percent removals of Al, Fe, Mn, and acidity that would be required to comply with water quality criteria at least 99% of the time;
- Critically evaluate the water chemistry data in order to categorize the AMD effects and then propose water-sampling strategies for each AMD category.
Summary:
Implementation of the TMDL strategy requires stream monitoring to assess the nature, concentration, and variability of pollution. Resources are usually inadequate to perform intensive and long-term monitoring on every water body that is affected by AMD. EPA did not provide watershed specific guidelines for conducting stream sampling. Rather, EPA and PADEP negotiated a minimum number of samples that would be used to determine the pollutant loading on water bodies that are affected by AMD. Since resources are limited, it is reasonable to ask whether all of the water bodies that are affected by AMD should be required to receive the same level of data collection. The severity of the pollution from AMD depends on the characteristics of the abandoned mines and of the stream. Therefore, application of the same sampling strategy for every watershed could be inadequate for some conditions and could be wasteful for other conditions.
Scope of Study:
This study was started in March 2000 in association with PADEP. Ten study areas in western Pennsylvania were selected. Preliminary surveys indicated that these streams were affected by AMD. Monitoring locations were selected by PADEP, and many were new sites that had not been previously sampled. Accurate flow measurements did not exist for any of the monitoring locations. Therefore, each site in this study was sampled multiple times, to include a range of seasons and flows. During each sampling trip, the stream flow was measured, and water samples were collected and subsequently analyzed. The parameters used in this study were pH, acidity (hot peroxide procedure), alkalinity, total suspended solids, sulfate, total aluminum, iron, and manganese. Aluminum, iron, manganese, acidity, and pH were target pollutants with respect to the water quality criteria.