AgdaPkt 2003-12-01 - Laserfiche WebLink

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io.l A I December 1, 2003 Subject Professional Services Agreement - Drainage Improvements to Garrett Park Recommendation Approve a professional services agreement with Kennedy /Jenks Consultants for design of drainage improvements to Garrett Park. Background In 1970, as part of one of the City's General Improvement Projects for Storm Drain Improvements, the City installed a drainage inlet upstream of the park, with a channel across the park and leading to an underground, 48" diameter pipe. The downstream neighborhood in Redwood City was developed over time, and homes were built immediately adjacent to the 48" pipe. When the original improvements for this channel were installed, the upstream drainage area (which is primarily unincorporated County), was mostly undeveloped. Since then, quite an increase in development has taken place, along with an accompanying increase in the amount of impervious surface. This new development has the impact of creating more storm water runoff. It is estimated that there is an increase of about 30% in the amount of runoff from the original condition. The inlet upstream of Garrett Park clogs with debris occasionally, due to the trash and debris that washes downstream and /or is dumped into the creek. Even with conscientious efforts on the part of the City's maintenance crews, the inlet got plugged during the heavy rains of December 2002. The plugging of the inlet caused the overflow and the subsequent damage to the claimants' properties. After studying the situation, City staff is recommending that modifications be made to the inlet structure, including enlarging the opening and reconstructing the grate, so that, even with the inevitable deposition of debris, the storm water can get into the pipe before overtopping the inlet and washing downstream to the adjacent property. This work will be designed now; advertisement for bid and construction will commence in the spring of 2004. -1-