subcatchment

It is a tidal subcatchment of the Hawkesbury River.

The river has nine subcatchment areas and has a number of tributaries and lakes along the length of the river.

In addition Low Impact Development (LID) and Best Management Practice (BMP) areas on the subcatchment can be modeled to reduce the impervious and pervious runoff.

Spatial variability in all of these processes is achieved by dividing a study area into a collection of smaller, homogeneous watershed or subcatchment areas, each containing its own fraction of pervious and impervious sub-areas.

It is integrated within the subcatchment and allows further refinement of the overflows, infiltration flow and evaporation in Rain Barrels, Vegetative Swales, Porous Pavement, Bio Retention Cell and Infiltration Trench.

SWMM tracks the quantity and quality of the flow generated within each subcatchment, and the flow rate, flow depth, and quality of water in each pipe and channel during a simulation period composed of multiple fixed or variable time steps.

You can have multiple LID's per subcatchment and we have had no issues having many complicated LID sub networks and processes inside the Subcatchments of SWMM 5 or any continuity issues not solvable by a smaller wet hydrology time step.

The hydrology component of SWMM operates on a collection of subcatchment areas divided into impervious and pervious areas with and without depression storage to predict runoff and pollutant loads from precipitation, evaporation and infiltration losses from each of the subcatchment.