USING CONSERVATION DEVELOPMENT CREDITS TO IMPLEMENT THE KALAMAZOO TMDL LOAD ALLOCATION

Net reductions from a variety of nonpoint sources, including existing and new development, are needed to reduce current phosphorus loadings by 43% to the load allocations specified in the TMDL for Lake Allegan and the Kalamazoo River. Planning tools in use for the area do not link land uses or changes in land uses to phosphorus loadings. Currently, planners can neither easily evaluate the net phosphorus load from, for example, a new subdivision, or a facility expansion or retrofit, nor compare the net phosphorus impact of two alternative site proposals. Such capability is necessary to manage new development requirements and incentive programs that will help implement the TMDL.This project illustrated how conservation credits could be generated and implemented through a series of case studies developed in a suite of integrated models specially tailored for this application. The suite includes CH2M HILL's WISE (Watershed Improvement through Statistical Evaluation) with custom-built trading and banking modules, and relies on selected output from EPA's PLOAD model. The case studies show how conservation development practices can lead to a better environmental result—i.e., lower net phosphorus impacts, than traditional site development approaches, and how the suite of tools can be used to develop and evaluate site plan alternatives.