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8. Manage and maintain the 9. Design a system to capture and treat water irrigation system carefully ,. ~,_ ~U .~ a A poorly maintained irrigation system wastes water, adds to surface runoff, and damages property. ^ Match watering schedule to plant needs, soil type, slope and season. ^ Eliminate leaks and spraying onto sidewalks immediately. ^ Install rain shut-off devices. ^ Upgrade to new technology irrigation controllers that adjust watering schedules to reflect weather conditions or soil moisture and include a rain shut-off device. ^ Refer to applications in the section Conserve Water. Water will be conserved, runoff reduced and your customer may save money on water bills, while protecting the San Francisco Bay watershed. Catching, slowing and retaining water will promote infltration and removal of pollutants, as well as minimize stormwater runoff. It can also add beauty and value to the landscape. Studies indicate that home values and leases of commercial buildings are higher if the building overlooks, or the home is within 300 feet of a water element. ^ Limit grading to protect existing patterns of drainage and retain natural topographic features that slow and store storm flows. ^ Incorporate design measures and treatment controls, such as landscape beds, detention basins, ponds, stormwater wetlands and/or vegetated swales, that are sized to treat at least 85% of average annual runoff. ^ Divert rain water from all down spouts to planters, swales or landscaped areas. Capture and filter runoff from parking lots into islands or planter strips or other treatment controls. Rain is directed into landscape beds. Rock cobble around stormdrains prevents mulch from entering the drain. ^ Design bioswales with flat bottoms of at least 18 inches across, and/or rock cobble at points of concentrated flow. ^ Specify turf alternatives for bioswales. ^ Plant a 24 inch buffer zone between areas receiving spray irrigation and impervious surfaces to keep over- spray and runoff out of stormdrains. stormwater runoff is reduced while water recycled on site fosters the removal of pollutants and encourages biodiversity. Downstream engineering costs are decreased. Property values can be increased. ~Na.4 s 1 s.'~~~r._ . 7 .. .. b ,`, .,~~ ~ ~ ~ ~.~ +~, ?,#f~"s. ~;c ., ''i1+G `~ k' . z~ ,, ; -: ~~~r~,,~~~ M ~ r~ ~, 4kria Site water flows to a bioswale, enhancing on-site infiltration and reducing contaminants. ~ Using Dry Wells to Capture Water from Downspouts Directing roof runoff to dry wells is a good way to reduce the amount of potable water used for landscape irrigation. Use of dry wells can improve stormwater quality, increase groundwater recharge, decrease runoff volume and peak flows, and decrease flooding potential. The captured water can be reused for watering gardens, lawns and trees. To construct a dry well, dig a hole in the ground -sized according to the amount of rooftop runoff received (typically 4 to 5 feet square and 2 to 3 feet deep, with a minimum of I foot soil on top) and fill with an open graded aggregate. The roof downspout is directed to the dry well which allows the water to inf Itrate after a storm. Dry wells must be located at least I 0 feet from any building to protect the foundation. Dry wells are less effective in soils with poor drainage. For more information, see "Roof Runoff Controls, SD-I I;' from the 2003 California stormwater BMP Handbook: New Development and Redevelopment, www.cabmphandbooks.com. c c i 48