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<br />PART TWO <br />SCOPE OF SERVICES <br />POR W A TEn CJRCULA TION ANALYSES <br />OF REDWOOD SHORES LAGOON <br /> <br />Background <br />During the years 1985 to 2003 CDM performed hydraulic analyses of the Redwood Shores <br />Lagoon- The analyses were performed to determine inlet capacities, culvert sizes, gravity (~utlel <br />sizes, discharge pump station capacities, and circulation rates throughout the Lagoon- <br /> <br />Since the 2003 hydraulic analyses, a hydrographjc sUTVey was perfonned on the entire Lagoon <br />and the results show that silt and other sediments have entered the Lagoon- The survey indicates <br />that at SOme locations the bottom elevation of the Lagoon has been raised between 0.5 an'! 2.5 <br />feet by sediment deposition. <br /> <br />Recent pipe and gate improvements, and sediment removal. have improved círculation within <br />Redwood Shores Lagoon. It is OUT understanding that the City wants to have hydraulic analyses <br />performed to determine the circulation rates with these improvements- <br /> <br />Scope of Services <br />CDM will perform the following tasks: <br /> <br />Task 1 - Modify the Extran Input and Perform Model Simulations <br />Using the information that the City will provide. and the existing SWMM link-node model as <br />shown on the attached Figure 3 from our January 2004 technical memoranda, the following <br />water circulation analyses will be perlonned: <br /> <br />Analysis 9 (Analyses 1 through 8 were in the January 2004 Technical Memorandum) <br />. Sediment in the conduits. The equivalent conduit sizes shown on the attached table. <br />. Belpipes 1 and 2 that are both 48-jnch diameter. <br />. Belpjpe 3 is 25 percent open. <br />. Belpipe 4 is closed. <br />. Pipe 1120 that is 54-inches diameter. <br />. Two new pumps at Marlin Drive. <br />. Pipes 10051 and 10061 are 90 percent blocked. <br /> <br />Analy$is 10 <br />Same as Analysis 9 with the following change: <br />Replace Pipe 15000 with a 30 cfs pump station that pumps water from the Lagoon to <br />Belmont Slough. <br /> <br />Analysis 11 <br />Same as AnaJysis 9 with two or three changes in conduit blockage percentages. The exact <br />conditions for this analysis will be detennined by the City after completion of Analyses 9 and 10. <br /> <br />Task 2 - Meet with the City Staff <br />CDM will meet with the City staff to djscuss the results of AnaJyses 9, 10, and 11. <br /> <br />CDNI <br /> <br />2 <br /> <br />WO6IRFIOO3.dDC <br /> <br />88H <br /> <br />600/S00.d <br /> <br />Z~8-1 <br /> <br />Vll ~mSZ6 <br /> <br />~BBJJ ~nuleM ~aJ-~O~d <br /> <br />~d1S: EO <br /> <br />9HZ-SO <br />