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Rain garden

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A rain garden is a planted depression that allows rainwater 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...

 from impervious
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...

 urban areas like roofs, driveways, walkways, parking lots, and compacted lawn areas the opportunity to be absorbed. This reduces rain runoff by allowing 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...

 to soak into the ground (as opposed to flowing into storm drain
Storm drain
A storm drain, storm sewer , stormwater drain or drainage well system or simply a drain or drain system is designed to drain excess rain and ground water from paved streets, parking lots, sidewalks, and roofs. Storm drains vary in design from small residential dry wells to large municipal systems...

s and surface water
Surface water
Surface water is water collecting on the ground or in a stream, river, lake, wetland, or ocean; it is related to water collecting as groundwater or atmospheric water....

s which causes erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...

, 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....

, flooding, and diminished 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...

). They can be designed for specific soils and climates. The purpose of a rain garden is to improve water quality in nearby bodies of water. Rain gardens can cut down on the amount of pollution reaching creeks and streams by up to 30%.

Native plants are recommended for rain gardens because they generally do not require fertilizer
Fertilizer
Fertilizer is any organic or inorganic material of natural or synthetic origin that is added to a soil to supply one or more plant nutrients essential to the growth of plants. A recent assessment found that about 40 to 60% of crop yields are attributable to commercial fertilizer use...

 and are more tolerant of one’s local climate, soil, and water conditions, and attract local wildlife such as native birds. The plants — a selection of wetland
Wetland
A wetland is an area of land whose soil is saturated with water either permanently or seasonally. Wetlands are categorised by their characteristic vegetation, which is adapted to these unique soil conditions....

 edge vegetation, such as wildflower
Wildflower
A wildflower is a flower that grows wild, meaning it was not intentionally seeded or planted. Yet "wildflower" meadows of a few mixed species are sold in seed packets. The term "wildflower" has been made vague by commercial seedsmen who are interested in selling more flowers or seeds more...

s, sedges
Cyperaceae
Cyperaceae are a family of monocotyledonous graminoid flowering plants known as sedges, which superficially resemble grasses or rushes. The family is large, with some 5,500 species described in about 109 genera. These species are widely distributed, with the centers of diversity for the group...

, rushes
Juncaceae
Juncaceae, the rush family, are a monocotyledonous family of flowering plants. There are eight genera and about 400 species. Members of the Juncaceae are slow-growing, rhizomatous, herbaceous plants, and they may superficially resemble grasses. They often grow on infertile soils in a wide range...

, fern
Fern
A fern is any one of a group of about 12,000 species of plants belonging to the botanical group known as Pteridophyta. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants...

s, shrub
Shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...

s and small tree
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...

s — take up excess water flowing into the rain garden. Water filters through soil layers before entering the groundwater system. Root systems enhance 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...

, maintain or even augment soil permeability, provide moisture redistribution, and sustain diverse microbial populations involved in biofiltration
Biofilter
Biofiltration is a pollution control technique using living material to capture and biologically degrade process pollutants. Common uses include processing waste water, capturing harmful chemicals or silt from surface runoff, and microbiotic oxidation of contaminants in air...

. Also, through the process of transpiration
Transpiration
Transpiration is a process similar to evaporation. It is a part of the water cycle, and it is the loss of water vapor from parts of plants , especially in leaves but also in stems, flowers and roots. Leaf surfaces are dotted with openings which are collectively called stomata, and in most plants...

, rain garden plants return water vapor
Water vapor
Water vapor or water vapour , also aqueous vapor, is the gas phase of water. It is one state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice. Under typical atmospheric conditions, water vapor is continuously...

 to the atmosphere
Atmosphere
An atmosphere is a layer of gases that may surround a material body of sufficient mass, and that is held in place by the gravity of the body. An atmosphere may be retained for a longer duration, if the gravity is high and the atmosphere's temperature is low...

. A more wide-ranging definition covers all the possible elements that can be used to capture, channel, divert, and make the most of the natural rain and snow that falls on a property. The whole garden can become a rain garden, and all of the individual elements that we deal with in detail are either components of it, or are small-scale rain gardens in themselves.

Restoring aspects of natural water cycle/mitigating the impact of urban development



In developed areas, natural depressions where storm water would pool, are filled in. The surface of the ground is often leveled
Regrading
Regrading is the process of raising and/or lowering the levels of land; such a project can also be referred to as a regrade. Regrading may be done on a small scale or on quite a large scale...

 or paved. Storm water is directed into storm drain
Storm drain
A storm drain, storm sewer , stormwater drain or drainage well system or simply a drain or drain system is designed to drain excess rain and ground water from paved streets, parking lots, sidewalks, and roofs. Storm drains vary in design from small residential dry wells to large municipal systems...

s which often may cause overflows of combined sewer systems or poisoning, erosion or flooding of waterways receiving the storm water runoff. Redirected storm water is often warmer than the 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...

 normally feeding a stream, and has been linked to upset in some aquatic ecosystems primarily through the reduction of dissolved oxygen
Oxygen saturation
Oxygen saturation or dissolved oxygen is a relative measure of the amount of oxygen that is dissolved or carried in a given medium. It can be measured with a dissolved oxygen probe such as an oxygen sensor or an optode in liquid media, usually water.It has particular significance in medicine and...

 (DO). Storm water runoff is also a source of a wide variety of pollutants washed off hard or compacted surfaces during rain events. These pollutants include volatile organic compounds pesticides, herbicides, hydrocarbons and trace metals Rain Gardens are designed to capture the initial flow of storm water and reduce the accumulation of toxins flowing directly into natural waterways through ground filtration. The National Science Foundation
National Science Foundation
The National Science Foundation is a United States government agency that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National Institutes of Health...

, the United States 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...

, and a number of research institutions are presently studying the impact of augmenting Rain Gardens with materials capable of capture or chemical reduction of the pollutants to benign compounds.

Rain gardens are often located near a building’s roof drainpipe (with or without rainwater tank
Rainwater tank
A rainwater tank is a water tank used to collect and store rain water runoff, typically from rooftops via rain gutters...

s). Most rain garden are designed to be an endpoint of drainage with a capacity to percolate all incoming water through a series of soil or gravel layers beneath the surface plantins. A French drain
French drain
A French drain, blind drain, rubble drain, rock drain, drain tile, perimeter drain, land drain or French ditch is a trench covered with gravel or rock that redirects surface and groundwater away from an area...

 may be used to direct a portion of the rainwater to a overflow location for heavier rain events. By reducing peak stormwater discharge, Rain Gardens extend hydraulic lag time and somewhat mimic the natural water cycle displaced by urban development and allow for 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. While Rain Gardens always allow for restored groundwater recharge, and reduced stormwater volumes, they may also increase 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....

 unless remediation
Remediation
Environmental remediation deals with the removal of pollution or contaminants from environmental media such as soil, groundwater, sediment, or surface water for the general protection of human health and the environment or from a brownfield site intended for redevelopment...

 materials are included in the design of the filtration layers .

The primary challenge of rain garden design centers on calculating the types of pollutants and the acceptable loads of pollutants the rain garden's filtration system can handle during storm-water events. This challenge is specifically acute when a rain event occurs after a longer dry period. The initial storm water is often highly contaminated with the accumulated pollutants from dry periods. Rain garden designers have previously focused on finding robust native plants and encouraging adequate biofiltration, but recently have begun augmenting filtration layers with media specifically suited to chemically reduce redox
Redox
Redox reactions describe all chemical reactions in which atoms have their oxidation state changed....

 of incoming polutant streams.

Rain gardens are beneficial for many reasons: improve water quality by filtering runoff, provide localized flood control
Flood control
In communications, flood control is a feature of many communication protocols designed to prevent overwhelming of a destination receiver. Such controls can be implemented either in software or in hardware, and will often request that the message be resent after the receiver has finished...

, aesthetically pleasing, and provide interesting planting opportunities. They also encourage wildlife and biodiversity
Biodiversity
Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...

, tie together buildings and their surrounding environments in attractive and environmentally advantageous ways, and provide significant partial solutions to important environmental problems that affect us all.

A rain garden provides a way to use and optimize any rain that falls, reducing or avoiding the need for irrigation
Irrigation
Irrigation may be defined as the science of artificial application of water to the land or soil. It is used to assist in the growing of agricultural crops, maintenance of landscapes, and revegetation of disturbed soils in dry areas and during periods of inadequate rainfall...

. They allow a household or building to deal with excessive rainwater runoff without burdening the public storm water systems. Rain gardens differ from retention basins, in that the water will infiltrate the ground within a day or two. This creates the advantage that the rain garden does not allow mosquito
Mosquito
Mosquitoes are members of a family of nematocerid flies: the Culicidae . The word Mosquito is from the Spanish and Portuguese for little fly...

es to breed.

History


The first rain gardens were created to mimic the natural water retention areas that occurred naturally before development of an area. The rain gardens for residential use were developed in 1990 in Prince George's County, Maryland
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....

, when Dick Brinker, a developer building a new housing subdivision
Subdivision (land)
Subdivision is the act of dividing land into pieces that are easier to sell or otherwise develop, usually via a plat. The former single piece as a whole is then known in the United States as a subdivision...

 had the idea to replace the traditional best management practices
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 ...

 (BMP) pond with a 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...

 area. He approached Larry Coffman, the county's Associate Director for Programs and Planning in the Department of Environmental Resources, with the idea. The result was the extensive use of rain gardens in Somerset, a residential subdivision which has a 300 – rain garden on each house’s property. This system proved to be highly cost-effective. Instead of a system of curbs
Curb (road)
A curb, or kerb , is the edge where a raised pavement/sidewalk/footpath, road median, or road shoulder meets an unraised street or other roadway.-Function:...

, sidewalk
Sidewalk
A sidewalk, or pavement, footpath, footway, and sometimes platform, is a path along the side of a road. A sidewalk may accommodate moderate changes in grade and is normally separated from the vehicular section by a curb...

s, and gutters
Street gutter
A street gutter is a depression running parallel to a road designed to collect rainwater flowing along the street and divert it into a storm drain. Where a curbstone is present, a gutter may simply be formed by the convergence of the road surface and the vertical face of the sidewalk; otherwise, a...

, which would have cost nearly $400,000, the planted drainage swales cost $100,000 to install. This was also much more cost effective than building BMP ponds that could handle 2-, 10-, and 100-year storm events. Flow monitoring done in later years showed that the rain gardens have resulted in a 75–80% reduction in stormwater runoff during a regular rainfall event.

This is also referred to as Water Sensitive Urban Design (WSUD) in Australia and low impact development
Low impact development
Low-impact development is a term used in the United States to describe a land planning and engineering design approach to managing stormwater runoff. LID emphasizes conservation and use of on-site natural features to protect water quality...

 (LID) in United States , and is cited by the EPA on their website as a success on the Stormwater Case Studies section of their website. This webpage has many links to information on Prince George’s County’s literature on implementing LID in a community.

Some de facto rain gardens predate their recognition by professionals as a significant LID tool. Any shallow garden depression implemented to capture and retain rain water within the garden so as to drain adjacent land without running off a property is at conception a rain garden — particularly if vegetation is maintained with recognition of its role in this function. Vegetated roadside swale
Swale (geographical feature)
A swale is a low tract of land, especially one that is moist or marshy. The term can refer to a natural landscape feature or a human-created one...

s, now promoted 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”, remain the conventional drainage system in many parts of the world from long before extensive networks of concrete sewers became the conventional engineering practice in the industrialized world.

What is globally new about such technology is the emerging rigor of increasingly quantitative understanding of how such tools may make 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...

 possible. This is as true for wealthy developed communities retrofitting 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...

 into built stormwater management systems, as for developing communities seeking a faster and more sustainable development path.

Characteristics



A rain garden requires an area where water can collect and infiltrate
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...

, and plants to maintain infiltration rates, diverse microbe communities, and water holding capacity. Transpiration
Transpiration
Transpiration is a process similar to evaporation. It is a part of the water cycle, and it is the loss of water vapor from parts of plants , especially in leaves but also in stems, flowers and roots. Leaf surfaces are dotted with openings which are collectively called stomata, and in most plants...

 by growing plants accelerates soil drying between storms. This includes any plant extending roots to the garden area.

Simply adjusting the landscape so that downspouts and paved surfaces drain into existing gardens may be all that is needed because the soil has been well loosened and plants are well established. However, many plants do not tolerate saturated roots for long and often more water runs off one's roof than people realize. Often the required location and storage capacity of the garden area must be determined first. Rain garden plants are then selected to match the situation, not the other way around.

Soil and drainage


When an area’s soils are not permeable
Permeability (fluid)
Permeability in fluid mechanics and the earth sciences is a measure of the ability of a porous material to allow fluids to pass through it.- Units :...

 enough to allow water to drain and filter properly, the soil should be replaced. This mixture should typically contain 60% sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...

, 20% compost
Compost
Compost is organic matter that has been decomposed and recycled as a fertilizer and soil amendment. Compost is a key ingredient in organic farming. At its most essential, the process of composting requires simply piling up waste outdoors and waiting for the materials to break down from anywhere...

, and 20% topsoil
Topsoil
Topsoil is the upper, outermost layer of soil, usually the top to . It has the highest concentration of organic matter and microorganisms and is where most of the Earth's biological soil activity occurs.-Importance:...

. Deep plant roots also create additional channels for storm water to filter into the ground. Sometimes a drywell with a series of gravel layers near the lowest spot in the rain garden will help facilitate percolation. However, a drywell placed at the lowest spot can become clogged with silt prematurely turning the garden into an infiltration basin
Infiltration basin
An infiltration basin , is a type of best management practice that is used to manage stormwater runoff, prevent flooding and downstream erosion, and improve water quality in an adjacent river, stream, lake or bay...

 defeating its purpose. Depression-focused recharge of polluted water into wells poses a serious threat and should be avoided. Similarly plans to install a rain garden near a septic system should be reviewed by a qualified engineer. The more polluted the water, the longer it must be retained in the soil for purification. This is often achieved by installing several smaller rain garden basins with soil deeper than the seasonal high water table
Water table
The water table is the level at which the submarine pressure is far from atmospheric pressure. It may be conveniently visualized as the 'surface' of the subsurface materials that are saturated with groundwater in a given vicinity. However, saturated conditions may extend above the water table as...

. In some cases lined 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 with subsurface drainage are used to retain smaller amounts of water and filter larger amounts without letting water percolate as quickly.

Rain gardens are at times confused with 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. Swale
Swale (geographical feature)
A swale is a low tract of land, especially one that is moist or marshy. The term can refer to a natural landscape feature or a human-created one...

s slope to a destination, while rain gardens do not; however, a bioswale may end with a rain garden. Drainage ditches may be handled like bioswales and even include rain gardens in series, saving time and money on maintenance. Part of a garden that nearly always has standing water is a water garden
Water garden
Water gardens, also known as aquatic gardens, are a type of man-made water feature. A water garden is defined as any interior or exterior landscape or architectural element whose primarily purpose is to house, display, or propagate a particular species or variety of aquatic plant...

, wetland
Wetland
A wetland is an area of land whose soil is saturated with water either permanently or seasonally. Wetlands are categorised by their characteristic vegetation, which is adapted to these unique soil conditions....

, or pond, and not a rain garden. Using the proper terminology ensures that the proper methods are used to achieve the desired results.

Plant selection


Plants selected for use in a rain garden should tolerate both saturated and dry soil. Using native plants is generally encouraged. This way the rain garden may contribute to urban habitats for native butterflies
Butterfly
A butterfly is a mainly day-flying insect of the order Lepidoptera, which includes the butterflies and moths. Like other holometabolous insects, the butterfly's life cycle consists of four parts: egg, larva, pupa and adult. Most species are diurnal. Butterflies have large, often brightly coloured...

, bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...

s, and beneficial insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

s.

Well planned plantings require minimal maintenance to survive, and are compatible with adjacent land use. Trees under power lines, or that up-heave sidewalks when soils become moist, or whose roots seek out and clog drainage tiles can cause expensive damage.

Trees generally contribute most when located close enough to tap moisture in the rain garden depression, yet do not excessively shade the garden. That said, shading open surface waters can reduce excessive heating of habitat. Plants tolerate inundation by warm water for less time because heat drives out dissolved oxygen
Oxygen saturation
Oxygen saturation or dissolved oxygen is a relative measure of the amount of oxygen that is dissolved or carried in a given medium. It can be measured with a dissolved oxygen probe such as an oxygen sensor or an optode in liquid media, usually water.It has particular significance in medicine and...

, thus a plant tolerant of early spring flooding may not survive summer inundation.

Australia

  • Healthy Waterways Raingardens Program promotes a simple and effective form of stormwater treatment, and aims to raise peoples’ awareness about how good stormwater management contributes to healthy waterways. The program encourages people to build raingardens at home, and its target is to see 10,000 raingardens built across Melbourne by 2013.
  • Melbourne Water’s database of Water Sensitive Urban Design projects, including 57 case studies relating to rain gardens/bioretention systems. Melbourne Water is the Victorian State Government agency responsible for managing Melbourne's water supply catchments.
  • Water By Design is a capacity building program that supports the uptake of Water Sensitive Urban Design, including rain gardens, in South East Queensland. It was established by the South East Queensland Healthy Waterways Partnership in 2005, as an integral component of the SEQ Healthy Waterways Strategy.

  • The Sydney Metropolitan Catchment Management Authority’s (CMA) Water Sensitive Urban Design (WSUD) Program increases the abilities and resources of individuals and organisations responsible for implementing WSUD; facilitates the exchange of information and embedding of WSUD in policy, practices and on-ground works. Case studies cover projects relating to planning and policy; industrial, greenfield an infill/brownfield sites; roadway retrofits; and educational and capacity building projects.
  • Kingston City Council, in Southern metropolitan Melbourne have designed and constructed a over 130 rain gardens as part of its Water Sensitive Urban Design projects since 2001.
  • Stringy Bark Creek rain garden project in Mount Evelyn, Victoria
    Mount Evelyn, Victoria
    Mount Evelyn is a suburb in Melbourne, Victoria, Australia, 37 km north-east from Melbourne's central business district. Its Local Government Area is the Shire of Yarra Ranges. At the 2006 Census, Mount Evelyn had a population of 9100.-History:...

     is part of a research program coordinated by the University of Melbourne
    University of Melbourne
    The University of Melbourne is a public university located in Melbourne, Victoria. Founded in 1853, it is the second oldest university in Australia and the oldest in Victoria...

     and Monash University
    Monash University
    Monash University is a public university based in Melbourne, Victoria. It was founded in 1958 and is the second oldest university in the state. Monash is a member of Australia's Group of Eight and the ASAIHL....

    . It is putting into practice new approaches to stormwater management, that focus on improving the health of creeks and rivers.

United States of America

  • The National Science Foundation
    National Science Foundation
    The National Science Foundation is a United States government agency that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National Institutes of Health...

    , granted a 2011 SBIR to Dr. Hanbae Yang and ABSMaterials to conduct developmental work and scientific documentation on the range of pollutants which can be controlled using Rain Gardens. The grant support long term column studies with controlled soil media containing Osorb
    Osorb
    Osorb is a swellable, organically-modified silica or glass capable of absorbing volatile organic compounds and other contaminants from water. The glass was discovered by Dr. Paul L. Edmiston and is trademarked by ABSMaterials, Inc.-History of discovery:...

     materials which have been demonstrated to capture and reduce numerous volatile organic compounds. A twin chamber Rain Garden has been built to capture runoff from a 120 space car parking lot and adjoining buildings on the College of Wooster campus. The two chambers are identical in design and plantings with the exception of on chamber being augmented with the volatile compound reducing agents. Column tests conducted in 2010 indicate the augmentation agents increase retention or destruction of pesticides and herbicides from 30% in a normal raingarden to over 90%. Dr. Yang, the lead researcher on the program is a noted environmental engineer and co-designer and developer of Rain Gardens. His graduate work at Ohio State University
    Ohio State University
    The Ohio State University, commonly referred to as Ohio State, is a public research university located in Columbus, Ohio. It was originally founded in 1870 as a land-grant university and is currently the third largest university campus in the United States...

    's OARDC was centered on Rain Garden and led to patented developments in stormwater runoff controls.

http://www.absmaterials.com/rain_gardens/cow-rain-garden
  • Maplewood
    Maplewood, Minnesota
    As of the census of 2000, there were 34,947 people, 13,758 households, and 9,190 families residing in the city. The population density was 2,017.5 people per square mile . There were 14,004 housing units at an average density of 808.5 per square mile...

    , Minnesota
    Minnesota
    Minnesota is a U.S. state located in the Midwestern United States. The twelfth largest state of the U.S., it is the twenty-first most populous, with 5.3 million residents. Minnesota was carved out of the eastern half of the Minnesota Territory and admitted to the Union as the thirty-second state...

     has implemented a policy of encouraging residents to install rain gardens. Many neighborhoods had swales added to each property, but installation of a garden at the swale was voluntary. The project was a partnership between the City of Maplewood, University of Minnesota
    University of Minnesota
    The University of Minnesota, Twin Cities is a public research university located in Minneapolis and St. Paul, Minnesota, United States. It is the oldest and largest part of the University of Minnesota system and has the fourth-largest main campus student body in the United States, with 52,557...

     Department of Landscape Architecture, and the Ramsey Washington Metro Watershed District. A focus group was held with residents and published so that other communities could use it as a resource when planning their own rain garden projects.

  • In Seattle
    Seattle, Washington
    Seattle is the county seat of King County, Washington. With 608,660 residents as of the 2010 Census, Seattle is the largest city in the Northwestern United States. The Seattle metropolitan area of about 3.4 million inhabitants is the 15th largest metropolitan area in the country...

    , a prototype project, used to develop a plan for the entire city, was constructed in 2003. Called SEA Street, for Street Edge Alternatives, it was a drastic facelift of a residential street. The street was changed from a typical linear path to a gentle curve, narrowed, with large rain gardens placed along most of the length of the street. The street has 11% less impervious surface than a regular street. There are 100 evergreen trees and 1100 shrubs along this 3-block stretch of road, and a 2-year study found that the amount of stormwater which leaves the street has been reduced by 98%.

  • 10,000 Rain Gardens is a public initiative in the Kansas City
    Kansas City, Missouri
    Kansas City, Missouri is the largest city in the U.S. state of Missouri and is the anchor city of the Kansas City Metropolitan Area, the second largest metropolitan area in Missouri. It encompasses in parts of Jackson, Clay, Cass, and Platte counties...

    , Missouri
    Missouri
    Missouri is a US state located in the Midwestern United States, bordered by Iowa, Illinois, Kentucky, Tennessee, Arkansas, Oklahoma, Kansas and Nebraska. With a 2010 population of 5,988,927, Missouri is the 18th most populous state in the nation and the fifth most populous in the Midwest. It...

     metro area. Property owners are encouraged to create rain gardens, with an eventual goal of 10,000 individual gardens. Mayor Kay Barnes
    Kay Barnes
    Kay Waldo Barnes is a former two-term mayor of Kansas City, Missouri. She was the Democratic nominee for of the United States House of Representatives in the 2008 election against Republican incumbent Sam Graves.-Biography:...

     took the unconventional advice of Lynn Hinkle to bring widespread use of rain gardens to offset the increasing demand on the city’s stormwater infrastructure.

  • The West Michigan Environmental Action Council has established Rain Gardens of West Michigan as an outreach water quality program. Also in Michigan, the Southeastern Oakland County Water Authority has published a pamphlet to encourage residents to add a rain garden to their landscapes in order to improve the water quality in the Rouge River watershed. In Washtenaw County
    Washtenaw County, Michigan
    Washtenaw County is a county in the U.S. state of Michigan. As of the 2010 census, the population was 344,791. Its county seat is Ann Arbor. The United States Office of Management and Budget defines the county as part of the Detroit–Warren–Flint Combined Statistical Area...

    , homeowners can volunteer for the Water Resources Commissioner’s Rain Garden program, in which volunteers are annually selected for free professional landscape design. The homeowners build the garden themselves as well as pay for landscaping material. Photos of the gardens as well as design documents and drainage calculations are available online.

  • The city of Atlanta, Georgia
    Georgia (U.S. state)
    Georgia is a state located in the southeastern United States. It was established in 1732, the last of the original Thirteen Colonies. The state is named after King George II of Great Britain. Georgia was the fourth state to ratify the United States Constitution, on January 2, 1788...

    , has established a public education project, the Clean Water Campaign (CWC), to encourage residents to learn about stormwater management and to add rain gardens to their properties. They do this through community workshops and an official website.

  • The city of Portland
    Portland, Oregon
    Portland is a city located in the Pacific Northwest, near the confluence of the Willamette and Columbia rivers in the U.S. state of Oregon. As of the 2010 Census, it had a population of 583,776, making it the 29th most populous city in the United States...

    , Oregon
    Oregon
    Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...

    , has established a Clean River Rewards program, to encourage residents to disconnect downspouts from the city’s combined sewer system and create rain gardens. Workshops, discounts on storm water bills, and web resources are offered.

  • The city of Austin
    Austin, Texas
    Austin is the capital city of the U.S. state of :Texas and the seat of Travis County. Located in Central Texas on the eastern edge of the American Southwest, it is the fourth-largest city in Texas and the 14th most populous city in the United States. It was the third-fastest-growing large city in...

    , Texas
    Texas
    Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

    , has established rain gardens as an “Innovative Water Quality Control”, per its Environmental Criteria Manual.


  • The US Fish and Wildlife Service provided a grant to the Wasilla Soil and Water Conservation District for a rain garden as a memorial for Steve Duncan, a long time advocate for soil and water conservation who recently died from cancer. What was to be a 20 feet (6.1 m) by 10 feet (3 m) rain garden, turned into over 100 feet (30.5 m) long by 10–12 feet wide. A brass plaque is being placed in the garden to recognized Steve's work with the local community and to teach kids the importance of water conservation. A story of it aired on Wed. May 20, 2009.

  • Students in the College of Architecture, Design, and Construction at Auburn University
    Auburn University
    Auburn University is a public university located in Auburn, Alabama, United States. With more than 25,000 students and 1,200 faculty members, it is one of the largest universities in the state. Auburn was chartered on February 7, 1856, as the East Alabama Male College, a private liberal arts...

     have just finished putting in rain gardens and bioswales around the Boykin Center in Auburn, Alabama, through a project called Green For Life. The students put many native plants in the rain gardens to help make it look beautiful. The University students also taught the students in the Boykin Center about rain gardens, rain barrels, native plants, and green benefits.

See also

  • 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...

  • Ecohydrology
    Ecohydrology
    Ecohydrology is an interdisciplinary field studying the interactions between water and ecosystems. These interactions may take place within water bodies, such as rivers and lakes, or on land, in forests, deserts, and other terrestrial ecosystems...

  • Low impact development
    Low impact development
    Low-impact development is a term used in the United States to describe a land planning and engineering design approach to managing stormwater runoff. LID emphasizes conservation and use of on-site natural features to protect water quality...

  • 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...

  • Microclimate
    Microclimate
    A microclimate is a local atmospheric zone where the climate differs from the surrounding area. The term may refer to areas as small as a few square feet or as large as many square miles...

  • 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...

  • Surface 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...

  • Urban runoff
    Urban runoff
    Urban runoff is surface runoff of rainwater created by urbanization. This runoff is a major source of water pollution in many parts of the United States and other urban communities worldwide.-Overview:...

  • 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 garden
    Water garden
    Water gardens, also known as aquatic gardens, are a type of man-made water feature. A water garden is defined as any interior or exterior landscape or architectural element whose primarily purpose is to house, display, or propagate a particular species or variety of aquatic plant...

  • Constructed wetland
    Constructed wetland
    A constructed wetland or wetpark is an artificial wetland, marsh or swamp created as a new or restored habitat for native and migratory wildlife, for anthropogenic discharge such as wastewater, stormwater runoff, or sewage treatment, for land reclamation after mining, refineries, or other...


  • Further reading


    • Dunnett, Nigel and Andy Clayden. Rain Gardens: Sustainable Rainwater Management for the Garden and Designed Landscape. Timber Press: Portland, 2007. ISBN 978-0-88192-826-6
    • Prince George’s County. 1993. Design Manual for Use of Bioretention in Stormwater Management. Prince George’s County, MD Department of Environmental Protection. Watershed Protection Branch, Landover, MD.
    • Prince George’s County, 2002. “Bioretention Manual”. Department of Environmental Resources, Landover, MD.
    • Michael L. Clar, Billy J. Barfield, and Thomas P. O’Connor. 2004. “Stormwater Best Management Practice Design Guide, Volume 2: Vegetative Biofilters.” US EPA, National Risk Management Research Laboratory.
    • Kraus, Helen, and Anne Spafford. Rain Gardening in the South: Ecologically Designed Gardens for Drought, Deluge & Everything in Between. Eno Publishers: Hillsborough, NC, 2009. ISBN 978-0-9820771-0-8

    External links