RDG prepared a Conditional Letter of Map Revision (CLOMR) for submittal to FEMA.  RDG built a HEC-RAS hydraulic model to evaluate the hydraulic grade line and water surface elevations under flood flow conditions for Refugio Creek.  The results of the modeling effort were used by FEMA to confirm the project was complaint with the National Flood Insurance Program and to issue the CLOMR to the community.

As a subconsultant to Mia Lehrer + Associates, RDG developed detailed conceptual designs for restoring ecological functions and public access to the highly modified Compton Creek, a major tributary to the LA River. 

RDG performed the hydrologic and hydraulic calculations for the Sixth Street Rain Gardens and developed a successful design that responded to the challenges of working with numerous site constraints including two underground culverts (one abandoned and discovered during construction and the existing 6th Street culvert).  Working with the cities of Berkeley and Albany, RDG was ultimately able to reduce localized flooding while also treating urban runoff prior to entering the creek.

RDG worked closely with the Contra Costa County Flood Control District to secure approval to modify the flood control channel.  Using the District's unsteady state HEC-RAS hydraulic model as a base, RDG re-ran the model under varying scenarios to determine the hydraulic effects of the project.

This modeling effort updated the previous HEC-RAS model for Lower Codornices Creek and analyzed the performance of the proposed restoration of Codornices Creek from San Pablo Avenue to 8th Street.

RDG developed a hydraulic model of this 800-ft long step-pool reach to determine flood capacity, velocities, and shear stress of the proposed design.  The results of the modeling, reference reach data collected by RDG, and the latest published research on step-pool systems helped to develop the project design.