San Francisco Stormwater Design Guidelines
High-density Residential
Figure 9. High-density Residential
In San Francisco, high-density residential development is classified as 40 or more living units per acre. Some defining characteristics of high-density residential are zero-lot line development, reduced, public open space, and high levels of imperviousness. In this context, the greatest opportunities for stormwater management reside in replacing impervious surfaces with pervious surfaces and adding green space to roofs and interior courtyards. Ample roof space with relatively low pollutant loads provides opportunities for eco-roofs and rainwater harvesting. Interior courtyards can accommodate landscape-based BMPs, permeable paving, and subsurface treatment or capture systems. Sidewalks and streets adjacent to high-density residential development are often the nearest public open spaces available to residents. As such, they are ideal places to site stormwater management BMPs that also improve streetscape aesthetics and provide wildlife habitat, such as biofiltration areas, street trees, green walls, and bioretention bulbouts. All of these measures help to manage stormwater runoff; they also reduce the volumes of stormwater generated by the site in the first place.
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Downspout Discharges to Vegetated Roof to Reduce Runoff
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Vegetated Roof to Reduce Runoff
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Green Wall to Slow Runoff
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Downspout Connected to Dry Well
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PermeablePaving in Pedestrian Areas
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Rain Garden for Bio-Infiltration
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Bio-Retention Planter with Curb Cuts
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Downspout Connected to Large-Scale Cistern for Rainwater Harvesting
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Multi-Purpose Design
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