A Framework and Strategies for Determining Reference Conditions for Streams with Legacy Sediments on Military Installations

The Army accomplishes its mission, in part, by training forces at military installations to conduct combat operations on land. It also is charged with meeting requirements of the United States Clean Water Act on those lands. To assist the Army, the U.S. Army Engineer Research and Development Center-Construction Engineering Research Laboratory develops tools to: address the priorities the military mission priorities, meet the requirements of environmental legislation, and support the stewardship of land resources. A critical issue is establishing appropriate baseline reference conditions for evaluating activities involving water resources. This study addresses that issue by developing a framework and strategies for determining reference conditions for streams on military installations with legacy sediments (pollutants which were generated by land uses prior to Army occupancy). Subsequently, a weight of evidence approach is recommended for determining the reference condition for streams with legacy sediments. This includes using a variety of strategies to define reference stream water quality and biotic integrity, plus flow and sediment regime. The resulting framework was successfully applied to Fort Benning, Georgia. With additional data, using a weight of evidence approach with these strategies should permit reference conditions to be determined for other streams with legacy sediments. The original document contains color images.