William E. Asher         Senior Oceanographer         AIRS Department         Applied Physics Laboratory         University of Washington      USGS      (U.S. Geological Survey)      National Water Quality      Assessment Program	Two models have been developed under this project. The first is LakeVOC, which predicts the change in concentration of a volatile organic compound (VOC) in both the epilimnion and hypolimnion of lakes and reservoirs in response to changes in source input and environmental parameters. The second model is StreamVOC, which calculates source apportionment for a particular VOC in a river or stream with multiple discrete and distributed source regions. Our objective is to develop a set of models for predicting how changes in sources and environmental conditions will affect surface water concentrations of volatile organic compounds. These models are designed to allow regulators to easily study the effects of policy, planning, mitigation, and operational strategies on achieving national water quality requirements.