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+ | [[File:Stream buffer.PNG|right|thumb|300 px|alt=This image shows a picture of a stream buffer|<font size=3>Typical stream buffer Image Courtesy of Emmons & Olivier Resources, Inc.</font size>]] | ||
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Stormwater runoff from residential, commercial, industrial and agricultural land uses contains pollutants that can contaminate water bodies. Stormwater runoff from impervious surfaces also can increase runoff velocities and contribute to streambank erosion. Swales and buffer strips are a type of stormwater treatment composed of vegetation and a porous subsoil medium. Buffer strips are vegetated areas adjacent to a waterway that prohibit stormwater runoff from flowing directly into a water body. | Stormwater runoff from residential, commercial, industrial and agricultural land uses contains pollutants that can contaminate water bodies. Stormwater runoff from impervious surfaces also can increase runoff velocities and contribute to streambank erosion. Swales and buffer strips are a type of stormwater treatment composed of vegetation and a porous subsoil medium. Buffer strips are vegetated areas adjacent to a waterway that prohibit stormwater runoff from flowing directly into a water body. | ||
The vegetation catches pollutants carried by stormwater, decreases the rate of flow and volume of runoff, and stabilizes the soil on the shoreline or bank, lessening erosion caused by runoff. A swale is a long, vegetated depression often used as a water conveyance system which is also designed to infiltrate water and remove sediment and pollutants from runoff. A swale, therefore, assists in recharging ground water and managing stormwater runoff quantity and quality. This fact sheet provides guidance on the design, implementation and maintenance of vegetated swales and buffer strips and on programs to educate the public and decision makers about installing them. | The vegetation catches pollutants carried by stormwater, decreases the rate of flow and volume of runoff, and stabilizes the soil on the shoreline or bank, lessening erosion caused by runoff. A swale is a long, vegetated depression often used as a water conveyance system which is also designed to infiltrate water and remove sediment and pollutants from runoff. A swale, therefore, assists in recharging ground water and managing stormwater runoff quantity and quality. This fact sheet provides guidance on the design, implementation and maintenance of vegetated swales and buffer strips and on programs to educate the public and decision makers about installing them. | ||
− | ==Benefits / | + | ==Benefits / pollution reduction== |
Properly designed swales and buffers protect and separate a stream, lake or wetland from future disturbance or encroachment and sustain the integrity of stream ecosystem habitats. Maintaining a buffer or swale upstream of surface waters reduces pollutant impacts from sediment, phosphorus, nitrogen and high temperature waters. Additional benefits include ground water recharge, channel protection, erosion control, aquatic and terrestrial riparian habitat, flood control and recreational and educational opportunities. | Properly designed swales and buffers protect and separate a stream, lake or wetland from future disturbance or encroachment and sustain the integrity of stream ecosystem habitats. Maintaining a buffer or swale upstream of surface waters reduces pollutant impacts from sediment, phosphorus, nitrogen and high temperature waters. Additional benefits include ground water recharge, channel protection, erosion control, aquatic and terrestrial riparian habitat, flood control and recreational and educational opportunities. | ||
Swales and buffer, when constructed properly, can remove a series of pollutants from stormwater runoff. Water quality removal rates for are variable and depend on a number of factors including slope, width, and vegetation. The Minnesota Stormwater Manual contains relevant data on pollutant removal efficiencies. | Swales and buffer, when constructed properly, can remove a series of pollutants from stormwater runoff. Water quality removal rates for are variable and depend on a number of factors including slope, width, and vegetation. The Minnesota Stormwater Manual contains relevant data on pollutant removal efficiencies. | ||
− | ==Program | + | ==Program development and implementation== |
Programs designed to facilitate the installation of swales and buffers for water quality protection take into account both the mechanism of implementation and the ideal design characteristics for maximum effectiveness. For additional information on developing a buffer ordinance see the Establishing a Buffer Ordinance fact sheet. The following elements can be implemented in a vegetated swale and buffer initiative. | Programs designed to facilitate the installation of swales and buffers for water quality protection take into account both the mechanism of implementation and the ideal design characteristics for maximum effectiveness. For additional information on developing a buffer ordinance see the Establishing a Buffer Ordinance fact sheet. The following elements can be implemented in a vegetated swale and buffer initiative. | ||
− | ===Awareness | + | ===Awareness campaigns=== |
Awareness campaigns inform businesses, developers, and property owners of the benefits of vegetated swales and buffers. Efforts can contribute to encouraging individuals and organizations to implement buffers on a voluntary basis, educating individuals on proper installation and maintenance. Suggested educational methods include: | Awareness campaigns inform businesses, developers, and property owners of the benefits of vegetated swales and buffers. Efforts can contribute to encouraging individuals and organizations to implement buffers on a voluntary basis, educating individuals on proper installation and maintenance. Suggested educational methods include: | ||
+ | *'''Brochures''' Develop informative brochures, and guidance for specific audiences such as businesses, contractors, developers, homeowners associations and garden clubs. | ||
+ | *'''Signage at municipal installations''' Locate signage at parks, government buildings, and parking lots identifying swales and buffers and explaining their functions and benefits. | ||
+ | *'''Workshops and seminars''' Workshops and seminars can be used to provide needed technical assistance to homeowners, property owners and citizens for establishing a swale or buffer on their property. | ||
− | + | ===Vegetated swale design=== | |
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− | ===Vegetated | ||
Vegetated swales are linear, channel-like surface depressions that can be utilized as conveyance to direct stormwater away from or around a structure, for treatment to remove pollutants from stormwater, to promote infiltration of runoff into the ground and as volume control for stormwater runoff. Vegetated swales can also be landscaped to provide an aesthetic appeal and provide natural habitat within an urban setting. | Vegetated swales are linear, channel-like surface depressions that can be utilized as conveyance to direct stormwater away from or around a structure, for treatment to remove pollutants from stormwater, to promote infiltration of runoff into the ground and as volume control for stormwater runoff. Vegetated swales can also be landscaped to provide an aesthetic appeal and provide natural habitat within an urban setting. | ||
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===Buffer design=== | ===Buffer design=== | ||
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[[File:Recommended buffer zones.PNG|right|thumb|300 px|alt=This ishows a picture of Recommended buffer zones|<font size=3>Recommended buffer zones. Image Adapted from Welsch (1991) by US EPA</font size>]] | [[File:Recommended buffer zones.PNG|right|thumb|300 px|alt=This ishows a picture of Recommended buffer zones|<font size=3>Recommended buffer zones. Image Adapted from Welsch (1991) by US EPA</font size>]] | ||
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**The grass filter should discharge into a wider forest buffer designed to infiltrate and treat remaining runoff, the riparian zone | **The grass filter should discharge into a wider forest buffer designed to infiltrate and treat remaining runoff, the riparian zone | ||
− | ==Maintenance | + | ==Maintenance considerations== |
Maintenance is essential to ensure a swale functions properly over time. Maintenance suggestions include: | Maintenance is essential to ensure a swale functions properly over time. Maintenance suggestions include: | ||
*Regular mowing of grass swales | *Regular mowing of grass swales | ||
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*Aeration or other mitigation to maintain the high pervious quality of the soil | *Aeration or other mitigation to maintain the high pervious quality of the soil | ||
− | ==Typical | + | ==Typical cost== |
The cost of installation of a vegetated swale or buffer strip varies greatly based on width, soil amendments, the use of check dams and vegetation. The cost of the installation of a vegetated swale is estimated at 💲0.50 per square foot, according to a 2004 study done by the Army Corps of Engineers. There will also be costs associated with labor and supplies for necessary maintenance. Financial help may be available through cost share programs and grants to offset the cost of installation. | The cost of installation of a vegetated swale or buffer strip varies greatly based on width, soil amendments, the use of check dams and vegetation. The cost of the installation of a vegetated swale is estimated at 💲0.50 per square foot, according to a 2004 study done by the Army Corps of Engineers. There will also be costs associated with labor and supplies for necessary maintenance. Financial help may be available through cost share programs and grants to offset the cost of installation. |
Stormwater runoff from residential, commercial, industrial and agricultural land uses contains pollutants that can contaminate water bodies. Stormwater runoff from impervious surfaces also can increase runoff velocities and contribute to streambank erosion. Swales and buffer strips are a type of stormwater treatment composed of vegetation and a porous subsoil medium. Buffer strips are vegetated areas adjacent to a waterway that prohibit stormwater runoff from flowing directly into a water body.
The vegetation catches pollutants carried by stormwater, decreases the rate of flow and volume of runoff, and stabilizes the soil on the shoreline or bank, lessening erosion caused by runoff. A swale is a long, vegetated depression often used as a water conveyance system which is also designed to infiltrate water and remove sediment and pollutants from runoff. A swale, therefore, assists in recharging ground water and managing stormwater runoff quantity and quality. This fact sheet provides guidance on the design, implementation and maintenance of vegetated swales and buffer strips and on programs to educate the public and decision makers about installing them.
Properly designed swales and buffers protect and separate a stream, lake or wetland from future disturbance or encroachment and sustain the integrity of stream ecosystem habitats. Maintaining a buffer or swale upstream of surface waters reduces pollutant impacts from sediment, phosphorus, nitrogen and high temperature waters. Additional benefits include ground water recharge, channel protection, erosion control, aquatic and terrestrial riparian habitat, flood control and recreational and educational opportunities.
Swales and buffer, when constructed properly, can remove a series of pollutants from stormwater runoff. Water quality removal rates for are variable and depend on a number of factors including slope, width, and vegetation. The Minnesota Stormwater Manual contains relevant data on pollutant removal efficiencies.
Programs designed to facilitate the installation of swales and buffers for water quality protection take into account both the mechanism of implementation and the ideal design characteristics for maximum effectiveness. For additional information on developing a buffer ordinance see the Establishing a Buffer Ordinance fact sheet. The following elements can be implemented in a vegetated swale and buffer initiative.
Awareness campaigns inform businesses, developers, and property owners of the benefits of vegetated swales and buffers. Efforts can contribute to encouraging individuals and organizations to implement buffers on a voluntary basis, educating individuals on proper installation and maintenance. Suggested educational methods include:
Vegetated swales are linear, channel-like surface depressions that can be utilized as conveyance to direct stormwater away from or around a structure, for treatment to remove pollutants from stormwater, to promote infiltration of runoff into the ground and as volume control for stormwater runoff. Vegetated swales can also be landscaped to provide an aesthetic appeal and provide natural habitat within an urban setting.
Applications
Design considerations The size of the swale including length, width, and depth is dependent upon soil conditions, ground water level, the area discharging stormwater, the amount of impervious area discharging stormwater, and the topography of the contributing area. The recommendations below are from Chapter 12 of the Minnesota Stormwater Manual.
Vegetation Vegetation can range from tall plants and grasses to a short turf grass depending upon the desired application of the swale. Any vegetation used should be water tolerant. Native vegetation is preferred with its ability to uptake water and filter pollutants like phosphorus and sediment. Roots of native vegetation grow deep to stabilize the soil and promote infiltration, and native vegetation does not require irrigation after the first year of establishment.
Review of a cross section of peer-reviewed studies identifies the following buffer characteristics that are most effective at filtering runoff and treating stormwater.
Maintenance is essential to ensure a swale functions properly over time. Maintenance suggestions include:
Typical buffer maintenance activities include:
The cost of installation of a vegetated swale or buffer strip varies greatly based on width, soil amendments, the use of check dams and vegetation. The cost of the installation of a vegetated swale is estimated at 💲0.50 per square foot, according to a 2004 study done by the Army Corps of Engineers. There will also be costs associated with labor and supplies for necessary maintenance. Financial help may be available through cost share programs and grants to offset the cost of installation.