A self-guided tour of Low Impact Developments in Clark County, WA

More information
For more information on LID types, design standards and examples, see the 2012 LID Technical Guidance Manual for Puget Sound, developed by the Washington State University, Puyallup Research & Extension Center and Puget Sound Partnership.



Above-ground planter – A large box of topsoil with timber sides. A raised bed provides accessibility to plants and is beneficial if there is limited space to grow plants.
Bioretention cells, swales, planters – Shallow, engineered landscape depressions that receive stormwater runoff from an area, with soil media and plants designed for specific pollutant removal; may or may not have underdrains.
Impervious – Not allowing water to pass through the surface material.
Lawn alternative – Low, ornamental perennials, groundcovers and native meadow grasses.
Mulch – A layer of decomposed organic materials used to blanket an area where vegetation is desired. The materials enrich the soil for better plant development while preventing erosion and decreasing evaporation from the ground.
Native plantings and trees – Using native plants reduces the amount of impervious surface and provides increased infiltration and interception of rainfall, wildlife habitat and aesthetic elements.
Permeable pavers – Manufactured modular systems of various materials, sizes and types with gaps between blocks; gaps are filled with permeable material to allow water infiltration.
Pervious concrete – Rigid pavement containing a cementitous material to bind aggregate without fine material; used to create large spaces for water infiltration.
Porous asphalt – Flexible pavement containing a bituminous binder to adhere aggregate without fine material; used to create large spaces for water infiltration.
Rain collection or rain barrels – A tank or barrel used to collect and store rain from roofs and gutters.
Rain garden – A shallow, non-engineered depression with native soil and plants designed to capture stormwater from a small contributing area.
Rainwater harvesting – Collection of surface rainwater for non-potable uses such as irrigation or grey-water flushing.
Site planning and design – A multi-disciplinary approach to site design that locates buildings, roadways and other features away from critical habitat areas and to minimize impervious surfaces and the impacts of development.
Soil amendments – Products such as gypsum and lime that are added to soil to improve its physical qualities, especially its ability to provide nutrition for plants.
Treatment train – A combination of two or more treatment facilities connected in series.
Underdrain – Perforated plastic pipes installed on the bottom of a stormwater feature, which is used to collect and remove excess runoff.
Vegetated swale – A landscape element designed to remove silt and pollution from surface water runoff.It is a drainage course with gently sloped sides, vegetation, compost and/or rock.
Vegetated roofs – An engineered system of a thin layer of soil and plants designed to capture rain on a roof.
Water-efficient plants and Xeriscaping – Landscaping and gardening in ways that reduce or eliminate the need for irrigation.