Comments on the Model Recalibration Report, the Hunts Point Model and Tallman Island Model

The runoff coefficient was the primary parameter used in both site-scale and area-wide calibration efforts. This coefficient is directly related to the type of land use and land cover observed within the drainage area. The land use was represented in the model as pervious and impervious surfaces assigned to subcatchment areas within the system. In the 2007 InfoWorks (IW) Model, the runoff coefficients corresponded only to the perviousness of the drainage area surface and dealt with connectivity through initial infiltration losses. The new recalibrated model was updated to use Directly Connected Impervious Area (DCIA) estimates to assign the runoff coefficient for impervious areas within the subcatchment systems, which accounts for the drainage area’s connectivity to the sewer systems.