Communities all over the world want to ensure the protection of their water quality while also ensuring they receive maximum benefits from every investment made. Some are conserving, enhancing, or restoring natural areas while also developing green infrastructure like rain gardens, Bioretention facilities, and vegetated roofs that imitate natural systems for the sake of stormwater management.
Green infrastructure is the term used to describe these practices and others that make use of or imitate natural resources in order to manage and treat stormwater runoff. Stormwater is controlled by green infrastructure by using it as a resource instead of waste, being directed either to engineered systems for the purpose of infiltration or being detained so that it enters the sewer system at a much slower rate.
There are a number of common green infrastructure elements that can be found in many communities.
Rain garden is a term normally used to describe areas that have been planted in order to capture and treat rainwater. Sometimes referred to as Bioretention facilities, many communities construct rain gardens adjacent to sidewalks and roadways for the purpose of collecting and managing stormwater. They are landscaped or vegetated depressions created with engineered layers of soil that helps treat stormwater runoff before it infiltrates into the underlying soil.
During rainfall, stormwater runoff flows along the curb line down the street gutter and into the rain garden. The stormwater that has been collected will then be permeated by the engineered sandy soil on the top and then the stone layer on the bottom. It will then seep into the ground in a process that is referred to as infiltration.
Trees and plants will absorb some of the water via evapotranspiration, after which any water still remaining will eventually evaporate once the rainfall has stopped. In heavy rainstorms, stormwater still enters the rain garden but some of the water may get past the inlet and head directly into the catch basin. In the event that the rain garden reaches full capacity, stormwater will overflow and head for the catch basin in the normal manner.
Stormwater green street
Stormwater green streets are planted areas akin to rain gardens that are designed for the collection and management of stormwater that has run off streets and sidewalks. Stormwater green streets are however normally constructed in the roadway and are often bigger than rain gardens, with varying lengths, soil depths, and widths depending on the particular roadway’s individual characteristics.
Permeable pavements make use of a wide array of techniques and materials including porous concrete or permeable pavers to enable water to get in between paving materials and then infiltrate into the earth. Permeable pavements are able to be used in place of the traditional concrete or asphalt, which are impervious to water.
Rain barrels and cisterns
Rain barrels and cisterns are receptacles that are watertight and designed for the capture and storing of stormwater from roofs and other surfaces that water cannot penetrate. Cisterns are frequently bigger than rain barrels and are more commonly installed at commercial properties. Cisterns can be situated either underground, on an elevated stand, or at ground level.
Rain barrels are often found in residential settings and connect to a roof’s existing downspout, allowing stormwater to be reused for the purposes of landscaping and watering plants.
A bioswale, also known as a dry swale, is the name given to a wide and shallow channel with bottom and side slopes that are covered by dense native vegetation. There are natural swales and they can also be constructed with the aim of promoting infiltration, reducing stormwater runoff’s flow velocity, and making the most of the time water spends in the swale to aid in the trapping of silt and particulate pollutants.
Bioswales are in common use around car parks, where pollution from automobiles that runs off of the parking lot can be treated prior to it entering the watershed.
Planter box is the name given to urban rain gardens that have vertical walls and come with bottoms that can be either open or closed. Planter boxes are normally located in downtown areas and are responsible for the collection and absorption of runoff from parking lots, sidewalks, and streets.
Planter boxes are particularly suited for use in areas that may have a limited amount of space and are an effective method of beautifying city streets.
Muller, Inc. has been an industry leader in stormwater management and green infrastructure for over fifteen years. Our certified team of green infrastructure experts has experience installing and maintaining all types of green infrastructure and stormwater best management practices throughout Northern Virginia, Maryland, and Washington, D.C.