AgdaPkt 2002-07-15 - Laserfiche WebLink

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IREPORT To the Honorable Mayor and City Council From the City Manager July 15, 2002 Subject Agreement for Professional Consultant Engineering Services for the Hydraulic Analysis of the Redwood Shores Lagoon System. Recommendation Approve an agreement with Camp Dresser McKee, Inc. (CDM) of Walnut Creek, California, for providing consultant engineering services for the Hydraulic Analysis of the Redwood Shores Lagoon System, in an amount not to exceed $49,940. Background The Redwood Shores Peninsula is bounded by the Belmont Slough to the north, San Francisco Bay to the east, Steinberger Slough to the south, and the Bayshore Freeway to the west. The interior waterway (lagoon) is a major focal point of the area and contributes to the area's visual aesthetics, aquatic habitat, and recreation. The lagoon also serves as a stormwater retention pond for the area, storing surface runoff during storm season. The main lagoon is approximately 9,000 feet long. It is in an east to west direction between Marine Parkway and Redwood Shoes Parkway. At the two ends, the lagoon becomes wider, and at mid-length it connects to two smaller lagoons located on either side of Madin Drive. These two lagoons are interconnected under Madin Drive by small diameter culverts. The newly developed Lido area, at the eastern end of Redwood Shores Peninsula, is currently isolated from the central lagoon, with the potential connection through a dredger channel and culverts under Shearwater Parkway. In recent years, the water quality at several locations within the waterway appeared problematic. An initial study has identified two possible factors. One is that the circulation and tidal exchange rate of the lago'~n may not be adequate, the other factor is the sedimentation in the lagoon may reach ~ degree to impact water circulation. To confirm these two possible factors and proceed with needed capital improvement projects, Engineering 8, Construction Services will evaluate the existing lagoon circulation system by performing a hydraulic simulation with computer modeling. Based on the result of the hydraulic simulation, the lagoon volume exchange rate for all waterways will be identified. The consultant will also work With City staff in formulating a program to take soundings in the Lagoon to determine the elevation of the bottom of those waterways where circulation is marginal. Any circulation deficiency will be .input back to the computer model with a proposed improvement. After the final confirmation, all improvement projects will be implemented in a future Capital Improvement Program.