Biological monitoring and land use data analysis were performed for a small (79,800 acre) watershed in west-central Indiana. A model was developed between Hilsenhoff biotic index and percentage of water (volume) draining through forestland at each sample site (R2.92, P < .002). This water volume model was found to explain more of the variation in biological integrity than USEPA and Ohio EPA habitat assessment methods, as well as, a land use model based upon percentage watershed surface area. Based on this water volume model, maps were created depicting regions within the watershed that had the greatest potential to damage water quality. Land acquisition/conversion projects based upon these maps should improve biological integrity/water quality more efficiently (requiring less land acquisition/conversion, and therefore lowering project costs, while increasing water quality benefits).