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<br />Atherton Creek
<br />2021 Multijurisdictional Local Hazard Mitigation Plan
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<br />deep flooding with slow velocity—especially when a channel migrates over a broad floodplain, redirecting high
<br />velocity flows and transporting debris and sediment. Flood severity is often evaluated by examining peak
<br />discharges. Peak flows used by FEMA to map floodplains within the planning area are listed in Table 11-6.
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<br />Table 11-6. Summary of Peak Discharges—San Mateo County
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<br />Source/Location
<br />Drainage Area
<br />(square miles)
<br />Discharge (cubic feet/second)
<br />10-Percent 2-Percent 1-Percent 0.2- Percent
<br />16th Avenue Drainage
<br />Southern Pacific Railroad Crossing d d d 490 d
<br />Highway 101 d d d 800 d
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<br />Cordilleras Creek
<br />At Alameda de las Pulgas 2.6 400 730 890 1,300
<br />At Stanford Lane 3.1 460 900 1,120 1,700
<br />At El Camino Real 3.3 470 940 1,170 1,800
<br />Old County Road 3.3 470 620f 680e, f 1,1906
<br />Bayshore Freeway 3.6 525 700g 850g 1,490g
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<br />El Granada Creek
<br />At Reservoir 0.5 160 250 290 370
<br />At Half Moon Bay 0.6 190 300 340 440
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<br />Industrial Branch
<br />At Colma Creek 1.5 490 720 800 970
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<br />19th Avenue Drainage Channel
<br />At South Pacific Railroad Crossing d d d 1,310 d
<br />At Delaware Street d d d 1,330 d
<br />At Bermuda Drive d d d 1,450 d
<br />Highway 101 d d d 1,500 d
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<br />At Railroad 5.0 350a 350a 350a, b 350c
<br />Belmont Creek
<br />At El Camino Real 2.5 570 1,000 1,200 1,400
<br />At Highway 101 2.8 660 1,200 1,400 1,600
<br /> Colma Creek
<br />At F Street 1.7 800 1,200 1,400 1,600
<br />Below Hickey Boulevard Tributary 6.0 1,700 2,900 3,400 4,100
<br />At USGS Gage in Orange Park 10.9 2,400 4,100 4,700 5,700
<br />Below Spruce Branch 12.7 2,500 4,400 5,000 6,100
<br />At San Francisco Bay 16.0 2,900 5,100 5,800 7,000
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<br />Denniston Creek
<br />At Reservoir 3.2 700 1,200 1,400 1,800
<br />Near Sheltercove Drive 3.8 780 1,300 1,600 2,000
<br />At Half Moon Bay 4.0 800 1,400 1,600 2,100
<br /> Easton Creek
<br />At Railroad 0.79 260 410 470 540
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<br />Holly Street Channel
<br />At Highway 101 0.4 240 370h 420h 420h
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