The objective of this municipal storm water assessment project was to delineate the storm water infrastructure for a small community in Montana, assess its integrity, and sample water and soil within the system and from surface water contributions to the system during storm events. The primary purpose of this sampling effort was to meet the requirements of the site Record of Decision (ROD) by defining possible contaminant sources. The sampling objective of the study was to measure the quantity and quality of storm water runoff from representative areas of concern where surface water may be impacted by metals contaminated runoff. A secondary objective was to collect baseline data for use in the storm water monitoring program to be implemented following completion of the Superfund remedy.
Specific field investigation activities to address the above objectives included:
• Surface water sampling of main stem and tributary streams and drainages during storm events using automated devices,
• Manual sampling and field parameter measurement of storm water runoff on an opportunistic basis during or following storm events,
• Measurement of stream discharge through direct and indirect methods, and
• Collection of concurrent precipitation data.
The monitoring portion of this project was designed to collect screening and enforcement quality data for use in the remedial design. Specifically, this investigation met the requirements for completion of the surface water remedial design in areas where contaminated runoff may impact surface water. The data was also utilized in the development of a performance monitoring program.