The Bijou Area is a complex regional stormwater pump-and-treat system in a Federal Emergency Management Agency (FEMA)-mapped flood zone. While the issues were complex, the system applied standard construction techniques in a series to provide efficient water quality treatment and flood control in an effective and easily maintainable manner. A key component of project was a bypass stormwater double box culvert, which maximized the efficiency of the system. The box culvert conveys upper watershed runoff through the highly developed commercial core directly into Lake Tahoe.
This approach allowed for more effective treatment of the commercial area runoff, which enters the pump-and-treat system. The culvert discharges directly into Lake Tahoe on a barren beach; therefore, the outfall structure would potentially have a visual impact to pedestrians and boaters during normal lake water levels.
Double box culvert system (Bijou Creek Drainage) separates the cleaner offsite run-on (Bijou Creek and upper watershed) from the more polluted onsite runoff (lower watershed). This separation of flows allows for the pump-and-treat system to target the highest constituent loaded runoff for treatment, thus providing better treatment efficiency.
SAGE worked closely with Cardno ENTRIX and the City of South Lake Tahoe to produce a design that had limited vertical presence and would incorporate site sands to match the color and texture of the surrounding beach. The design followed the Tahoe Regional Planning Agency (TRPA) ordinance and satisfied local land use regulations and environmental protection codes.