In our ongoing efforts to improve watershed assessments through advances in the analysis of environmental data and in modeling, MapTech has been a leader in developing assessment methodologies and modeling techniques.  MapTech regularly assists the Commonwealth of Virginia in developing new assessment methodologies, e.g., a study was recently conducted to determine if Dissolved Oxygen (DO) and pH violations in lakes and free-flowing streams were caused by natural conditions.   To support the development of aquatic life TMDLs, in watersheds impacted by resource extraction, MapTech developed a biometrics model to relate water quality parameters to the health of the benthic macroinvertebrate community.   MapTech pioneered the development of methodologies for incorporating Bacterial Source Tracking (BST) data into the TMDL process, from assessment to implementation plan development.  Working with the Cadmus Group, MapTech took a prominent role in demonstrating the use of the methodology for EPA┬┤s Region 6.