Center for Watershed Protection. 2017. Pollutant Load Reduction Credit Tool. Crediting Framework Product #4 for the project Making Urban Trees Count: A Project to Demonstrate the Role of Urban Trees in Achieving Regulatory Compliance for Clean Water. Center for Watershed Protection, Ellicott City, MD. The Center for Watershed Protection Developed a Pollutant Load Reduction Credit for tree planting. This national credit can be adopted by regulatory agencies who wish to offer a science-based credit that encourages greater use of tree planting for meeting total maximum daily load (TMDL) requirements. The Pollutant Load Reduction Credit Tool allows the user to calculate annual reductions in nutrients and sediment loads for an individual tree and for a tree planting scenario based upon this credit.