Models and Tools

SPARROW modeling: is used to estimate long-term average values of water characteristics, such as the amount of a contaminant that is delivered downstream, based on existing monitoring data, location and strength of contaminant sources, and characteristics of the landscape.

STEPL: The Pollutant Load Estimation Tool (PLET) is replacing the Spreadsheet Tool for Estimating Pollutant Loads (STEPL). PLET uses the same underlying formulas as STEPL, but in a more user-friendly web interface.  The PLET employs simple algorithms to calculate nutrient and sediment loads from different land uses, and the load reductions that would result from the implementation of various best management practices (BMPs).

TNRRAT: The Tennessee Runoff Reduction Assessment Tool (TNRRAT) was designed to help engineers, landscape architects, and other designers to create successful permanent stormwater management designs that protect water quality and meet the Tennessee MS4 Permanent Stormwater Permit requirements.

EPA – Materials and Technical Tools: As part of the materials and technical tools associated with numeric nutrient criteria derivation, N-STEPS has developed an overview of nutrient and response variables, factsheets on available statistical tools, compiled and described models commonly used in nutrient water quality modeling, and provided access to nutrient relevant literature.

NRCS – Revised Universal Soil Loss Equation:  It is a computer model containing both empirical and process-based science in a Windows environment that predicts rill and interrill erosion by rainfall and runoff.  The USDA-Agricultural Research Service (ARS) is the lead agency for developing the RUSLE2 model.  The ARS, through university and private contractors, is responsible for developing the science in the model and the model interface.

Nutrient and Sediment Estimation Tools for Watershed Protection: The purpose of this document is to identify and catalog many of the tools that are currently in use to estimate nitrogen, phosphorus, and sediment losses and to identify the uses for which these tools are most appropriate. Estimation tools can vary widely in terms of the land uses to which they are applicable, the scale at which they can estimate losses, the data requirements, and the sophistication of their estimates.