Community Foundation of Santa Cruz County

Projects

Commercial/Office/Retail

Community Foundation of Santa Cruz County

Description

Recently completed and located at the southeasterly corner of Soquel Drive and Aptos Rancho Road, the new office building and parking lot for Community Foundation of Santa Cruz County was designed to meet LEED (Leadership in Energy and Environmental Design) requirements for post-development storm water runoff rate and quantity mitigation measures. This once undeveloped, 0.65 acre site is now covered with 0.53 acre of impervious surface and 0.12 acre of permeable pavement and landscaping. This increase in impervious surfaces required installation of a retention/detention system to mitigate the increase in storm water runoff rate. Ifland designed a permeable pavement system for the parking spaces and a retention/detention holding basin under a portion of the parking lot. Storm water is collected from the building roof and transmitted to the drain rock bed under the permeable parking lot pavement. The surface runoff from the parking lot will drain through the permeable pavement, into the drain rock bed and will ultimately drain to three 20-foot deep percolation pits. The depth of the pits was found to be necessary once the project geotechnical consultant determined that soil with a good percolation rate was at least 10 feet below the ground surface. Using the County of Santa Cruz Design Criteria, Ifland prepared a drainage study calculating the allowable pre-development runoff, the storage requirements and the percolation rate to assure that the system emptied within 48 hours. The three seepage pits have catch basins over each one with a silt and grease trap for maintaining water quality.

 

The system provides enough retention volume that no runoff will leave the site except by percolation for up to a 2-year, 24-hour storm event. For larger storms, the system will limit the runoff to 5-year predevelopment rates for up to 10-year events. When accumulated runoff from even greater storms exceeds the storage capacity of the system, controlled discharge will occur via an overflow weir.

 

 


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Entrance Plaza
 
Groundwater Recharge
 
Pervious Concrete Parking
   
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