 |
Chagrin River Watershed Partners, Inc. |
|
Low Impact Development
What is Low Impact Development
 |
 |
Low Impact Development (LID) is a design strategy that aims to minimize the impact of development on the local watershed. It works by maintaining and replicating the natural hydrologic patterns that the landscape had prior to development.
Conventional approaches to design and development typically create large areas that are impervious to stormwater. As development occurs, buildings, parking lots, and streets replace or cover the natural soils and vegetation and allow water to run over them at an increased rate. Conventional approaches to stormwater management typically collect the storm water runoff and convey it to a stormwater facility, usually a pond.
LID practices use several integrated design techniques to mimic the natural hydrology of a particular landscape.
- Micro-scale stormwater retention and detention areas
- Reduction of impervious surfaces
- Lengthening of flow paths and runoff time
Preservation of environmentally sensitive areas and site features – such as riparian setbacks, wetlands, steep slopes, mature trees, floodplains, woodlands, and highly permeable soils.
These solutions can be integrated into the infrastructure of a development and have the added bonus of being more cost effective and aesthetically pleasing than traditional, storm water conveyance systems.
Typical Components of a LID Design
Permeable pavements or porous pavements are best suited for low traffic areas such as sidewalks and parking lots. These pavements allow stormwater to infiltrate into the underlying soils thereby promoting recharge and the treatment of pollution as well as reducing the volume of rainfall runoff produced by impermeable sidewalks and parking lots.
Green roofs reduce energy costs, lower the heat island effect, enhance air quality, and conserve valuable land that would otherwise be required for stormwater runoff controls.
Bioretention systems are used to detain runoff water long enough for infiltration and pollution removal to occur. Their design is based upon local soil types, site conditions, and land uses and is quite cost effective.
Grass Buffer Strips reduce runoff velocity and filter particulate matter.
Sand filter provides aeration and drainage of the planting soil and assists in the flushing of pollutants from soil materials.
Grass Swales are primarily used along residential streets and highways. They reduce runoff velocity and act as filtration/infiltration devices. Grass channels are most effective when the flow depth is minimized and the detention time is maximized.
Tree Boxes are primarily used along streets were plantings of shrubs and trees are used on side walks. The shrubs and threes have to be species specific to with stand long periods of drought and flooding typical floodplain species can be used. Tree boxes are useful for controlling flow, reducing stormwater temperature and removing pollutants from the stormwater.
For More Information
For more information about Low Impact Development, visit these websites: Low Impact Development Center, Inc..
Natural Resources Defense Council, Stormwater Strategies - Low Impact Development Approach
LID for Home Owners
Home owners can make a significant contribution to stormwater management in their neighborhoods. They can do this by installing simplistic features such as Rain Gardens and Rain Barrels to their landscape. These stormwater management tools have shown to have a very positive impact on local water quality and quantity management. They have also shown to help in recharging local ground water supplies. To learn more about these tools please click on the links on the right.
|
|