HEC RAS 4.1.0: Does Water Quality Routine Consider Storage Areas ? in Hydraulics and Floodplain Modeling Posted December 28, 2012 · Report reply My unsteady RAS model includes a reservoir and a few storage areas am curious to try out the water quality routine in RAS 4.1.0. I know that the computations are based water quality cells, which are mid points between two cross sections. I want to know if there is another way to incorporate a storage area in the model than input its stage vs storage from a DSS? Any insight you can provide is greatly appreciated. Thanks !