REDPOLL (Regional Estimation of Diffuse POLlution Loads) is a grid-based watershed model developed to estimate spatio-temporal delivered pollution loads across large-scale basins. It is engineered to overcome the limitations of traditional unit-load methods, providing a screening-level evaluation of non-point source (NPS) runoff characteristics in response to dynamic environmental changes.

• Estimation of Land-based Pollution Loads Inflowing into Major Habitats of the Yellow Sea / Korea Marine Environment Management Corporation (KOEM) (2018)

• Spatial Discretization: Partitioning of the target basin into a regular square grid system for localized mass balance and load calculations.

• Explicit Hydrological Simulation: Separately simulates direct runoff, baseflow, and evapotranspiration. For direct runoff, users can choose between the SCS Curve Number (CN) method or the Green-Ampt infiltration model.

• EMC-based Source Loading: Estimates pollutant discharge for each grid cell using land-use specific Event Mean Concentrations (EMC).

• Delivery Ratio Integration: Reflects the reduction of pollutants during the routing process to provide realistic delivered load estimates at the basin scale.

• Temporal Resolution: Operates at a daily time-step (1-day interval) for efficient long-term simulation.