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<br /> <br />Dam Failure <br /> <br />Table 8-1. San Mateo County Dams with Potential to Endanger Lives and Property <br /> <br /> <br />Name <br /> <br />National <br />ID# <br /> <br /> <br />Water Course <br /> <br /> <br />Owner <br /> <br />Year <br />Built <br /> <br />Dam <br />Type <br />Crest <br />Length <br />(feet) <br /> <br />Height <br />(feet) <br />Storage <br />Capacity <br />(acre-feet) <br />Drainage <br />area <br />(sq. mi.) <br />Extremely High Downstream Hazard <br />Bear Gulch CA00658 Tributary, San <br />Francisco Bay <br />California Water <br />Service Company <br />1896 Earth 730 61 672 0.2 <br />Emerald Lake 1 <br />Lower <br />CA00668 Lower Emerald Lake Emerald Lake <br />Country Club <br />1885 Earth 280 57 45 0.25 <br />Felt Lakea CA00670 Tributary, Los <br />Trancos Creek <br />Stanford University 1930 Earth 590 67 900 0.2 <br />Lower Crystal <br />Spring <br />CA00127 San Mateo Creek SF PUC Water <br />Department <br />1888 Gravity 600 140 57,910 28.71 <br />Pilarcitos CA00128 Pilarcitos Creek SF PUC Water <br />Department <br />1866 Earth 520 103 3,100 3.8 <br />San Andreas CA00129 Tributary, San Mateo <br />Creek <br />SF PUC Water <br />Department <br />1870 Earth 727 107 19,027 4.4 <br />Searsville CA00669 Corte Madera Creek Stanford University 1890 Gravity 260 68 952 14.8 <br />Spencer Lake CA00673 Tributary, San <br />Francisco Bay <br />Town of Hillsborough 1876 Earth 400 87 73 0.2 <br />High Downstream Hazard <br />Coastways c Coastways Ranch <br />Crocker CA00672 Sanchez Creek Town of Hillsborough 1890 Earth 200 45 22 0.26 <br />Laurel Creek CA00901 Laurel Creek City of San Mateo 1969 Earth 287 40 55 0.9 <br />Notre Dame CA00674 Belmont Creek City of Belmont b Earth 210 51 120 0.53 <br />Pomponio Ranch c Private Entity <br />a. Felt Lake is within Santa Clara County, approximately 1,300 feet from San Mateo boundary lines. It has been included here due to its <br />proximity to the county. <br />b. Year built unavailable. <br />c. Coastways and Pomponio Ranch dams are not included in the national inventory <br />Sources: San Mateo County OES 2015; U.S. Army Corps of Engineers National Inventory of Dams 2016; DSOD 2020 <br /> <br />Inundation Mapping <br />A key element for EAPs required for dams in California is a map defining the potential downstream inundation <br />should the dam fail. The DSOD reviews and approves inundation maps prepared by licensed civil engineers and <br />submitted by dam owners for extremely high, high, and significant hazard dams and their critical appurtenant <br />structures. Inundation maps approved by DSOD are a tool used to develop emergency action plans. They provide <br />general information for emergency planning. For this risk assessment, available dam failure inundation mapping <br />prepared by DSOD was combined into a single inundation area. The combined dam failure inundation area is <br />shown in Figure 8-2. Simultaneous failure of all dams is highly unlikely, but the assessment provides information <br />adequate for planning purposes. <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br />8-5