Soakaway pits are excavations in the ground filled with clean granular stone or other void forming material that receives “clean” runoff designed to infiltrate into the native soil. Soakaway pits are designed with an overflow and an optional subdrain feature. Key features for Soakaway pit designs are highlighted in the diagram below.


Parameter Name Description Default Value
Storage Layer
POROSITY Fraction of void space (pores) in the gravel storage layer 0.4
Initial Water Level Depth of water in the storage layer at the start of a model run 0