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7.A <br /> Outpatient Center Project, because the Douglas Avenue pumping station hac1����r <br /> limited capacity prior to construction of the Midpoint Technology Park, excess runoff <br /> ponded at the lowest areas adjacent to the freeway, covering roughly two-thirds of the <br /> Midpoint property and all of the Stanford project site, sometimes to depths in excess of <br /> three feet at the lowest spot. To protect the then-proposed Technology Park <br /> improvements, the new buildings on the site were built elevated above the maximum, <br /> 100-year flood elevation. Furthermore, to prevent a worsening of existing flooding <br /> elsewhere within the drainage basin, all parking and landscaped areas were left low to , <br /> maximize the volume of available storm water storage. Upon completion of the <br /> Midpoint Technology Park, water would begin backing up from the Douglas Avenue <br /> pumping station when the rainfall intensity exceeded a one-year storm, and would reach <br /> maximum depths on the Technology Park site of app�oximately 1.2 feet during a 10- <br /> year storm and 2.3 feet during a 100-yea� storm according to calculations provided in <br /> Wagstaff and Associates, Environmental Impact Report for the Stanford Medicine <br /> Outpatient Cenfer Project, June 2006 <br /> Plans to improve the Douglas station's pumping capacity are at a standstill because of <br /> existing flooding problems at the adjacent Fifth Avenue drainage basin and flow <br /> constraints downstream of the Bayfront Canal. <br /> Areas draining to the Broadway, Fifth Avenue, and Dougfas pump stations all discharge <br /> to the Bayfront Canal. In addition, the largest contributor to the Bayfront Canal is the <br /> Atherton Channel. This channel receives storm water runoff from the City of Menlo <br /> Park, the Town of Atherton, and unincorporated areas of San Mateo County. These <br /> areas comprise approximately 5,000 acres of the approximately 6,000 acres draining to <br /> the Bayfront Canal, or about 83% of the contributory area according to <br /> Kennedy/Jenks/Chilton, Storm Drainage, Water Sysfem, and Sanitary Sewers Master <br /> Plan, City of Redwood City, 1986. The canal borders low-lying mobile home parks <br /> north of the freeway, and flows easterly through a bank of tide gates that discharge into <br /> the Westpoint Slough of the San Francisco Bay. When high tides in the slough coincide <br /> with peak upstream storm water discharges, the canal backs up and regularly threatens <br /> the adjacent area. <br /> Approximately $6 million remains available in the city's Capital Improvement Program <br /> fund for the improvement of the Fifth Avenue pump station and drainage area. In 2002, <br /> a 66-inch diameter storm pipe was constru�ted a{ong Fifth Avenue and continued <br /> underneath Highway 101. In 2005, the storm pipe system flowing into the Fifth Avenue <br /> pump station was improved, and in 2007 the pump station outfall structure was <br /> constructed. However, the pipe construction stopped short of the location where a new <br /> pump station was to be built. Construction of the new pump station was halted due to <br /> unsuccessful negotiations with the owner of the Harbor Village Mobile Home Park for <br /> the required easement. <br /> Even if both the Fifth Avenue and the Douglas pump stations were improved, the <br /> ultimate constraint is still the capacity of the Bayfront Canal. At high tides, further <br /> pumping into the canal will cause back-flooding into adjacent areas. Improvement of <br /> the Bayfront Canal is a regional issue, as the canal receives storm water from multiple <br /> jurisdictions. <br /> To address concerns about site access during flooding events which affect Broadway, <br /> the city has researched various water barrier and flow diversion technologies as <br /> temporary immediate options. Water barriers can likely be implemented to maintain an <br />