Open Flows CivilStorm is a fully-dynamic hydraulic modeling application that analyzes complex stormwater systems and solves the St Venant equations. OpenFlows CivilStorm assists engineers working on both complex land development projects and large-scale stormwater management studies to model every aspect of their stormwater systems, including rainfall, runoff, inlet capture and bypass, gravity and pressure piping, detention ponds, outlet structures, open channels, culverts, and more.