WA: Pierce County: Small Rain Garden Technical Guide

Document prepared 8/30/2006 SMALL RAIN GARDEN TECHNICAL GUIDE Intent This technical design guide will help you decide if a rain garden is right for your site. The use of Low Impact Development (LID) techniques, such as rain gardens, can reduce the size of... More

Document prepared 8/30/2006 SMALL RAIN GARDEN TECHNICAL GUIDE Intent This technical design guide will help you decide if a rain garden is right for your site. The use of Low Impact Development (LID) techniques, such as rain gardens, can reduce the size of or entirely eliminate the need for stormwater ponds and conveyance systems. They reduce development costs while providing positive aesthetic and environmental benefits such as pollution treatment and groundwater recharge of stream and aquifers. This guide will be updated periodically as the technology develops. Wood Chip Mulch Above Ponding Elevation 2 to 3 inches depth RAIN GARDEN SECTION Seasonal High Groundwater Elevation 4 1 Engineered Soil (Compost Amended Soil) 18 inch (minimum) Well Draining Soil 12 inch (minimum) Maximum Water Depth 3 inches High Water Elevation Bottom Area of Rain Garden Compost Mulch Below Ponding Elevation 2 to 3 inches depth Rain gardens are shallow, small, heavily vegetated stormwater retention system Less