Urban rainwater land plans help to address the serious set of problems that many urban communities are facing around stormwater management. The rapid conversion of land to urban and suburban areas has profoundly affected how water flows during and following storm events by increasing volumes of water and pollutants entering rivers, lakes, and estuaries. These changes have greatly degraded both water quality and habitat in the majority of urban stream systems.
Current construction practices include removal of natural water-retention features in the landscape (including soil and vegetation) in order to construct buildings, roads and other community infrastructure. Removing these features, which naturally help to moderate absorption into the water table, allows stormwater to release into urban streams in large amounts during short, concentrated periods of time. Most urban areas also have a high percentage of hard-surfaced paved areas, such as parking lots and roads; these surfaces also increase the speed and quantity of the flow of stormwater into streams.
The Clean Water Act, drafted by Congress in 1987, divides stormwater management solutions into two categories: nonstructural and structural. Nonstructural controls are those that help to reduce the volume of development runoff and pollutants. Examples of nonstructural controls include using products that contain less pollutants, improved urban design, diversion of downspouts into porous surfaces, conservation of natural areas, and improved watershed and land use planning. Structural stormwater controls are designed to reduce the volume of water and pollutants released in storms. These strategies include use of rainwater harvesting systems such as rain barrels and cisterns, permeable pavement, infiltration trenches, rain gardens, and roadside bioswales.
Urban rainwater land plans often address not only the stormwater runoff from city roofs and paved surfaces through structural and nonstructural solutions, but address social issues as well. Community engagement strategies, in the form of open discussion meetings and design ‘charrettes’, assist neighborhood residents in understanding the importance of urban stormwater management practices and engage them in helping to define design criteria. These projects often involve careful research of the architectural style of the neighborhood and evaluation of the lifestyles of the residents. Sustainability strategies are also often addressed through the development of short- and long-term maintenance support plans. Some projects address specific neighborhood issues such as high unemployment rates by building in pilot job training/employment programs.