The Groundwater flow in SWMM 5 is actually made up of three components:
1. A groundwater flow computed from the coefficient a1 and exponent b1
2. A groundwater flow computed from the coefficient a2 and exponent b2 and
3. A Surface Water / Groundwater Interaction coefficient a3
The total Groundwater flow is the sum of the flow from 1, 2 and 3 – normally 2 is the opposite of 1.
