Mass Loading Methodology — BMP Trains 2020
Overview
This methodology outlines how BMP Trains 2020 computes average annual pollutant mass loading as the product of pollutant concentration and runoff volume. The approach relies on Event Mean Concentrations (EMCs), long-term hydrologic simulations, and land use characteristics, including DCIA, NDCIA, and composite curve numbers (CCN). Runoff calculations are derived from multi-decade rainfall datasets across five meteorological regions, incorporating data from 160 rainfall stations. The methodology follows established hydrologic principles and references Harper and Baker (2007) as well as a 2010 FDEP draft rule, both of which provide detailed runoff coefficients and EMC values used in the BMP Trains model.
Key Components
- Definition and purpose of mass loading
- EMC values and land use variability
- Annual runoff calculations from long-term rainfall simulation
- Hydrologic parameters: DCIA, NDCIA, CCN
- Region-specific runoff coefficients
- Foundational research and regulatory sources