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City of San Mateo Municipal Code.


(a) Implementing stormwater best management practices into the landscape and grading design plans to minimize runoff and to increase on-site rainwater retention and infiltration are required and must be consistent with City stormwater management requirements.

(b) Project applicants shall refer to the local agency or Regional Water Quality Control Board for information on any applicable stormwater technical requirements.

(c) All planted landscape areas are required to have friable soil to maximize water retention and infiltration.

(d) Where physically feasible, landscape areas shall be designed for capture and infiltration capacity that is sufficient to prevent runoff from impervious surfaces (i.e., roof and paved areas) from either: (1) the one-inch, 24-hour rain event; or (2) the 85th percentile, 24-hour rain event, and/or additional capacity as required by any applicable local, regional, State or Federal regulation.

(e) Stormwater projects shall incorporate the following elements to improve on-site stormwater and dry weather runoff capture and use:

(1) Grade impervious surfaces, such as driveways, during construction to drain to vegetated areas.

(2) Minimize the area of impervious surfaces such as paved areas, roof and concrete driveways.

(3) Incorporate pervious or porous surfaces (e.g., gravel, permeable pavers or blocks, pervious or porous concrete) that minimize runoff.

(4) Direct runoff from paved surfaces and roof areas into planting beds or landscaped areas to maximize site water capture and reuse.

(5) Incorporate rain gardens, cisterns, and other rain harvesting or catchment systems.

(6) Incorporate infiltration beds, swales, basins and drywells to capture stormwater and dry weather runoff and increase percolation into the soil.

(7) Consider constructed wetlands and ponds that retain water, equalize excess flow, and filter pollutants.