Note: There are three sub flow components in the calculation of the groundwater flow from a SWMM 5 Subcatchment.
1st Component: Flow = Groundwater Flow Coef. * (LowerDepth – Aquifer Bottom to Node Invert) ^ Groundwater Flow Exponent
2 nd Component: Flow = SurfaceWater Flow Coef. * (Aquifer Bottom to Water Surface – Aquifer Bottom to Node Invert) ^ SurfaceWater Flow Exponent
3rd Component: Flow = SurfaceWater-Groundwater Flow Coef. * (Aquifer LowerDepth * Aquifer Bottom to Node Invert)
The total flow is the sum of all three components.
via Blogger http://www.swmm5.net/2013/07/swmm5-groundwater-flow-components.html