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Capacity and I/I Assessment <br />City of Redwood City (0011239.02)3-13 Woodard & Curran, Inc. <br />Sanitary Sewer Capacity Master Plan November 2023 <br />3.4 INFILTRATION/INFLOW ANALYSIS <br />The Redwood City sanitary sewer is subject to significant amounts of I/I, resulting in high peak flows during wet weather <br />events. In the Main City Area, wet weather peaking factors (ratio of PWWF to average BWF) based on the model- <br />predicted flow for the 10-year design storm range from about 4 to over 20, with an overall average of about 9. Table 3-4 <br />tabulates the average and peak flows by flow meter area and estimated peak RDI/I rates and wet weather peaking <br />factors. Figure 3-6 and Figure 3-7 show bar graphs of peak RDI/I rates and wet weather peaking factors by flow meter <br />area, and Figure 3-8 shows a map of the flow meter areas color-coded by magnitude of wet weather peaking factor. <br />Table 3-4:RDI/I Rates and Peaking Factors by Flow Meter Area <br />Flow Meter <br />Area1 <br />ABWF <br />(mgd) <br />ADWF2 <br />(mgd) <br />Contrib. <br />Area <br />(acres) <br />Peak <br />RDI/I3 <br />(mgd) <br />PWWF3 <br />(mgd) <br />Peak RDI/I <br />rate <br />(gpd/acre) <br />Wet <br />Weather <br />Peaking <br />Factor4 <br />FM01 0.07 0.07 65 0.37 0.48 5,700 7.3 <br />FM02 0.08 0.10 80 0.70 0.84 8,700 11.2 <br />FM03 0.11 0.17 249 1.64 1.85 6,600 16.9 <br />FM045 0.19 0.19 182 1.10 1.40 6,000 7.5 <br />FM05 0.09 0.09 111 1.13 1.24 10,100 13.8 <br />FM06 0.03 0.06 50 0.97 1.04 19,400 30.9 <br />FM07 0.05 0.07 68 0.68 0.76 9,900 14.0 <br />FM08SW5 0.08 0.08 119 0.51 0.65 4,300 7.7 <br />FM09 0.09 0.09 144 1.75 1.90 12,100 21.2 <br />FM10 0.13 0.14 208 1.28 1.50 6,100 11.3 <br />FM115 0.05 0.15 69 2.23 2.41 32,300 45.7 <br />FM12 0.03 0.05 54 0.72 0.79 13,300 27.4 <br />FM13 0.07 0.13 99 1.90 2.06 19,100 28.1 <br />FM145 0.02 0.02 92 0.19 0.22 2,000 11.6 <br />FM155 0.06 0.06 85 1.26 1.38 14,700 24.5 <br />FM17 0.09 0.10 125 1.33 1.49 10,700 15.9 <br />FM185 0.12 0.14 80 0.39 0.61 4,800 5.3 <br />FM195 0.10 0.10 118 0.26 0.43 2,200 4.5 <br />FM20 0.05 0.05 42 0.47 0.56 11,400 11.5 <br />FM215 0.14 0.18 66 0.44 0.73 6,700 5.2 <br />FM225 0.05 0.05 29 0.14 0.24 5,000 4.5 <br />FM235 0.12 0.20 93 0.73 0.99 7,800 8.1 <br />FM24 0.10 0.14 56 0.35 0.56 6,200 5.4 <br />FM255 0.28 0.28 142 0.94 1.42 6,600 5.2 <br />FM265 0.05 0.05 20 0.19 0.28 9,200 5.1 <br />FM275 0.25 0.25 141 1.33 1.74 9,400 7.0 <br />FM285 0.13 0.13 40 0.65 0.88 16,300 6.5 <br />ATTY/RESO.0077/CC RESO SEWER SYSTEM MANAGEMENT PLAN - EXHIBIT A <br />REV: 07-14-25 LF <br /> <br />Page 148 of 317