Low-impact development is a term used in the United States to describe a land planning

Land use planning

Land-use planning is the term used for a branch of public policy encompassing various disciplines which seek to order and regulate land use in an efficient and ethical way, thus preventing land-use conflicts. Governments use land-use planning to manage the development of land within their...

 and engineering

Environmental engineering

Environmental engineering is the application of science and engineering principles to improve the natural environment , to provide healthy water, air, and land for human habitation and for other organisms, and to remediate polluted sites...

 design approach to managing stormwater

Stormwater

Stormwater is water that originates during precipitation events. It may also be used to apply to water that originates with snowmelt that enters the stormwater system...

 runoff

Surface runoff

Surface runoff is the water flow that occurs when soil is infiltrated to full capacity and excess water from rain, meltwater, or other sources flows over the land. This is a major component of the water cycle. Runoff that occurs on surfaces before reaching a channel is also called a nonpoint source...

. LID emphasizes conservation

Water conservation

Water conservation refers to reducing the usage of water and recycling of waste water for different purposes such as cleaning, manufacturing, and agricultural irrigation.- Water conservation :Water conservation can be defined as:...

 and use of on-site natural features to protect water quality

Water quality

Water quality is the physical, chemical and biological characteristics of water. It is a measure of the condition of water relative to the requirements of one or more biotic species and or to any human need or purpose. It is most frequently used by reference to a set of standards against which...

. This approach implements engineered small-scale hydrologic controls to replicate the pre-development hydrologic regime

Surface-water hydrology

Surface-water hydrology is a field that encompasses all surface waters of the globe...

 of watersheds

Drainage basin

A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...

 through infiltrating

Infiltration (hydrology)

Infiltration is the process by which water on the ground surface enters the soil. Infiltration rate in soil science is a measure of the rate at which soil is able to absorb rainfall or irrigation. It is measured in inches per hour or millimeters per hour. The rate decreases as the soil becomes...

, filtering

Filtration

Filtration is commonly the mechanical or physical operation which is used for the separation of solids from fluids by interposing a medium through which only the fluid can pass...

, storing, evaporating

Evaporation

Evaporation is a type of vaporization of a liquid that occurs only on the surface of a liquid. The other type of vaporization is boiling, which, instead, occurs on the entire mass of the liquid....

, and detaining runoff close to its source.

LID is similar to sustainable urban drainage systems

Sustainable urban drainage systems

Sustainable Drainage Systems , sometimes known as Sustainable Urban Drainage Systems , are designed to reduce the potential impact of new and existing developments with respect to surface water drainage discharges.-Background:...

(SUDS), a term used in the United Kingdom, water-sensitive urban design

Water-sensitive urban design

Water-sensitive urban design is a land planning and engineering design approach which integrates the urban water cycle, including stormwater, groundwater and wastewater management and water supply, into urban design to minimise environmental degradation and improve aesthetic and recreational...

 (WSUD), a term used in Australia, natural drainage systems a term used in Seattle, Washington and "Onsite Stormwater Management", a term used by the Washington State Department of Ecology.

Alternative to conventional stormwater management practices

A concept that began in Prince George's County

Prince George's County, Maryland

Prince George's County is a county located in the U.S. state of Maryland, immediately north, east, and south of Washington, DC. As of 2010, it has a population of 863,420 and is the wealthiest African-American majority county in the nation....

, Maryland in 1990, LID began as an alternative to traditional stormwater best management practices (BMPs)

Best management practice for water pollution

Best Management Practices is a term used in the United States and Canada to describe a type of water pollution control. Historically the term has referred to auxiliary pollution controls in the fields of industrial wastewater control and municipal sewage control, while in stormwater management ...

 installed at construction projects. Officials found that the traditional practices such as detention ponds

Detention basin

A detention basin is a stormwater management facility installed on, or adjacent to, tributaries of rivers, streams, lakes or bays that is designed to protect against flooding and, in some cases, downstream erosion by storing water for a limited period of a time. These basins are also called "dry...

 and retention basin

Retention basin

A retention basin is used to manage stormwater runoff to prevent flooding and downstream erosion, and improve water quality in an adjacent river, stream, lake or bay. Sometimes called a wet pond or wet detention basin, it is an artificial lake with vegetation around the perimeter, and includes a...

s were not cost-effective and the results did not meet water quality goals. The Low Impact Development Center, Inc., a non-profit water resources research organization, was formed in 1998 to work with government agencies and institutions to further the science, understanding,and implementation of LID and other sustainable environmental planning and design approaches, such as Green Infrastructure and the Green Highways Partnership.

The LID design approach has received support from the U.S. Environmental Protection Agency

United States Environmental Protection Agency

The U.S. Environmental Protection Agency is an agency of the federal government of the United States charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress...

 (EPA) and is being promoted as a method to help meet goals of the Clean Water Act

Clean Water Act

The Clean Water Act is the primary federal law in the United States governing water pollution. Commonly abbreviated as the CWA, the act established the goals of eliminating releases of high amounts of toxic substances into water, eliminating additional water pollution by 1985, and ensuring that...

. Various local, state, and federal agency programs have adopted LID requirements in land development codes and implemented them in public works projects. LID techniques can also play an important role in Smart Growth

Smart growth

Smart growth is an urban planning and transportation theory that concentrates growth in compact walkable urban centers to avoid sprawl and advocates compact, transit-oriented, walkable, bicycle-friendly land use, including neighborhood schools, complete streets, and mixed-use development with a...

 and Green infrastructure

Green infrastructure

Green Infrastructure is a concept originating in the United States in the mid-1990s that highlights the importance of the natural environment in decisions about land use planning. In particular there is an emphasis on the "life support" functions provided by a network of natural ecosystems, with an...

 land use planning.

Typical LID practices and controls

Planning practices include several related approaches that were developed independently by various practitioners. These differently named approaches include similar concepts and share similar goals in protecting water quality.

• Conservation design, also called Conservation Development
• Better Site Design
• Green Infrastructure
  Green infrastructure
  Green Infrastructure is a concept originating in the United States in the mid-1990s that highlights the importance of the natural environment in decisions about land use planning. In particular there is an emphasis on the "life support" functions provided by a network of natural ecosystems, with an...
  
  .

Planners select structural LID practices for an individual site in consideration of the site's land use

Land use

Land use is the human use of land. Land use involves the management and modification of natural environment or wilderness into built environment such as fields, pastures, and settlements. It has also been defined as "the arrangements, activities and inputs people undertake in a certain land cover...

, hydrology

Hydrology

Hydrology is the study of the movement, distribution, and quality of water on Earth and other planets, including the hydrologic cycle, water resources and environmental watershed sustainability...

, soil type, climate

Climate

Climate encompasses the statistics of temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle count and other meteorological elemental measurements in a given region over long periods...

 and rainfall patterns. There are many variations on these LID practices, and some practices may not be suitable for a given site. Many are practical for retrofit

Retrofit

Retrofitting refers to the addition of new technology or features to older systems.* power plant retrofit, improving power plant efficiency / increasing output / reducing emissions...

 or site renovation projects, as well as for new construction. Frequently used practices include:

• Bioretention
  Bioretention
  Bioretention is the process in which contaminants and sedimentation are removed from stormwater runoff. Stormwater is collected into the treatment area which consists of a grass buffer strip, sand bed, ponding area, organic layer or mulch layer, planting soil, and plants...
  
   cells, also known as rain gardens
• Cistern
  Cistern
  A cistern is a waterproof receptacle for holding liquids, usually water. Cisterns are often built to catch and store rainwater. Cisterns are distinguished from wells by their waterproof linings...
  
  s and rain barrels
• Green roof
  Green roof
  A green roof is a roof of a building that is partially or completely covered with vegetation and a growing medium, planted over a waterproofing membrane. It may also include additional layers such as a root barrier and drainage and irrigation systems...
  
  s
• Pervious concrete
  Pervious concrete
  Pervious concrete is a special type of concrete with a high porosity used for concrete flatwork applications that allows water from precipitation and other sources to pass directly through, thereby reducing the runoff from a site and allowing groundwater recharge. The high porosity is attained by a...
  
  , also called "porous pavement", similar to Permeable paving
  Permeable paving
  Permeable paving is a range of materials and techniques for paving roads, cycle-paths, parking lots and sidewalks that allow the movement of water and air around the paving material. Although some porous paving materials appear nearly indistinguishable from nonporous materials, their environmental...
  
  
• Grassed swales, also known as bioswale
  Bioswale
  Bioswales are landscape elements designed to remove silt and pollution from surface runoff water. They consist of a swaled drainage course with gently sloped sides and filled with vegetation, compost and/or riprap...
  
  s.
• Commercially manufactured stormwater management devices that capture pollutants (e.g., media filters) and/or aid in on-site infiltration

Benefits of LID

• Habitat
  Habitat
  * Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
  
   protection
• Improved management of water quantity (e.g. reduced risk of flood
  Flood
  A flood is an overflow of an expanse of water that submerges land. The EU Floods directive defines a flood as a temporary covering by water of land not normally covered by water...
  
  ing)
• Reduction of impervious surface
  Impervious surface
  Impervious surfaces are mainly artificial structures--such as pavements that are covered by impenetrable materials such as asphalt, concrete, brick, and stone--and rooftops...
  
  s and runoff (peak flow volume and rate)
• Groundwater
  Groundwater
  Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock...
  
   recharge through infiltration
  Infiltration (hydrology)
  Infiltration is the process by which water on the ground surface enters the soil. Infiltration rate in soil science is a measure of the rate at which soil is able to absorb rainfall or irrigation. It is measured in inches per hour or millimeters per hour. The rate decreases as the soil becomes...
  
  
• Water quality improvements
• Community value (i.e. increased aesthetics)
• Cost savings.

See also

• Rainwater harvesting
  Rainwater harvesting
  Rainwater harvesting is the accumulating and storing of rainwater for reuse before it reaches the aquifer. It has been used to provide drinking water, water for livestock, water for irrigation, as well as other typical uses. Rainwater collected from the roofs of houses and local institutions can...
  
  
• Sustainable development
  Sustainable development
  Sustainable development is a pattern of resource use, that aims to meet human needs while preserving the environment so that these needs can be met not only in the present, but also for generations to come...
  
  
• Sustainable urban drainage systems
  Sustainable urban drainage systems
  Sustainable Drainage Systems , sometimes known as Sustainable Urban Drainage Systems , are designed to reduce the potential impact of new and existing developments with respect to surface water drainage discharges.-Background:...
  
  
• Water pollution
  Water pollution
  Water pollution is the contamination of water bodies . Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds....
  
  

External links

• Pervious Concrete Blog – Discussion on the latest in Pervious Concrete Technology
• UC Davis Center for Water and Land Use – Provides a map with approximately 40 case studies of LID on the west coast. Also provides a detailed stormwater calculator for development.
• Center for Watershed Protection – Provides practical guidance for runoff reduction
• Low Impact Development Center – A water quality research organization; many links to green infrastructure, LID practices, projects and stormwater resources
• City of Redmond – Low Impact Development examples in a small city
• Case Study: Incorporating LID into Stormwater Management U.S. EPA
• Low Impact Development Urban Design Tools