Stormwater Management BMPs

Stormwater best management practices (BMPs) reduce polluted stormwater runoff into our local waterways.

Page updated on Jan 7, 2020 at 10:45 AM

Stormwater-Friendly BMPs and Landscaping Practices

The following list includes both structural and non-structural practices that are commonly recommended to mitigate drainage and erosion concerns. These practices can be used by any property owner and support the City’s Eco-City Clean Waterways initiatives. The practices on this list include structural stormwater best management practices (BMPs) approved for use in meeting stormwater regulations (per the Virginia Stormwater BMP Clearinghouse website), as well as smaller-scale homeowner versions of these practices and stormwater-friendly landscaping activities. Structural BMPs on this list are considered green infrastructure BMPs that strive to replicate the natural water cycle and manage stormwater onsite near its source to reduce impact on water quality, flooding, and stream bank erosion.

Click on the links below for more information on design, installation, maintenance, and additional resources.
Rain Barrels 
Cisterns 
Rain Gardens 
Flow Thru Planter Boxes 
Dry Wells
Infiltration Trench
Permeable Pavement
Green Roofs
Urban Nutrient Management Plans
Conservation Landscaping with Native Plants
Native Tree Planting

Choosing a BMP for an Erosion or Drainage Problem

The following webinar links present the materials from the February 2, 2019 Soak It Up! Stormwater Solutions for Homeowners workshop hosted by the City and the  Northern Virginia Regional Commission.  The webinar discusses the impacts of inadequate stormwater management, conventional solutions, and stormwater best management practice alternatives. For each BMP, the webinar will describe what it is, the function & application, and benefits & limitations. The webinar is intended for homeowners who are considering implementing a BMP for an erosion or drainage problem rather than as a condition of development.

VCAP Funding

Property owners are encouraged to install BMPs on their property to address erosion and drainage issues. The City partners with the  Northern Virginia Soil and Water Conservation District (NVSWCD) to administer the  Virginia Conservation Assistance Program (VCAP) to provide technical assistance and grant funding – pending availability of funds – for applicable projects.

The VCAP Contractor List includes contractors who are familiar with stormwater BMPs and the Virginia Conservation Assistance Program, administered by the  Northern Virginia Soil and Water Conservation District. Note that the City does not endorse any specific company. It is always recommended to ask contractors for a statement of their qualifications and follow up on their references, as well as getting at least three bids for any work to be done. 

Rain Barrels

A rain barrel is a barrel-shaped container placed under your downspout to collect rainwater. You can then use it for watering plants, washing your car, and reducing your water bill. Rain barrels are a simple, efficient, low-cost method for homeowners to collect and recycle water. A rain barrel is a rainwater harvesting BMP when the water is reused. 

rain barrel

Design & Installation

Guidance for voluntary installation by homeowners:

Standards for rainwater harvesting approved for use in meeting stormwater regulations:

Inspection & Maintenance

Inspection and maintenance should be performed at least annually. Determination of whether a rain barrel is properly functioning would include certification of the following:

rain barrel checklist

Resources

Credits for Annual Maintenance

Stormwater Utility Fee credits are available for residential townhome and single-family individual lots with rain barrels and for non-residential and residential condominium properties that use rain barrels as part of rainwater harvesting. Refer to the credit manual for more information.

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Cisterns

Cisterns are tanks used to catch rainwater running off roofs from a downspout. Cisterns are like large rain barrels. You can then save on your water bill by using the collected water for irrigation or other building uses if certain restrictions are met. A cistern is a rainwater harvesting BMP when the water is reused.

Cistern

Design & Installation

Guidance for voluntary installation by homeowners:

  • Cisterns may be purchased commercially.
  • VCAP Contractor List includes contractors who are familiar with stormwater BMPs and the Virginia Conservation Assistance Program, administered by the  Northern Virginia Soil and Water Conservation District. Note that the City does not endorse any specific company. It is always recommended to ask contractors for a statement of their qualifications and follow up on their references, as well as getting at least three bids for any work to be done. 

Standards for rainwater harvesting approved for use in meeting stormwater regulations:

Inspection & Maintenance

Inspection and maintenance should be performed at least annually. Determination of whether a cistern is properly functioning would include certification of the following:

cistern checklist

Resources

Credits for Annual Maintenance

Stormwater Utility Fee credits are available for residential townhome and single-family individual lots with cisterns and for non-residential and residential condominium properties that use cisterns as part of rainwater harvesting. Refer to the credit manual for more information.

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Rain Gardens

Rain gardens are considered micro-bioretention filters that are appropriate for single-family homes and townhouses. Like larger bioretention filters, rain gardens are bowl-shaped planted areas or swales where runoff can collect and be used by plants and/or soak into the ground. During storms, runoff typically ponds 6 to 12 inches above a surface mulch layer and then rapidly filters through a mixture of sand, soil, and organic material.

Often the ground below the rain garden is excavated and filled in with more permeable soil. Plants are selected to tolerate both flooding and drought. The photos below show a rain garden and a bioretention area that have been recently planted. As plants mature the gardens will look fuller.

In some rain gardens and in larger bioretention filters, an underdrain returns filtered stormwater to the storm drain system where infiltration rates are too low. Mosquito prevention is achieved when designed correctly so that the ponded water drains within 24-48 hours, which is shorter than needed for mosquito reproduction.

Rain Garden Bioretention

Design & Installation

Guidance for voluntary installation by homeowners:

Standards for bioretention approved for use in meeting stormwater regulations:

Inspection & Maintenance

Inspection and maintenance should be performed at least annually. Determination of whether a rain garden is properly functioning would include certification of the following: rain garden checklist

Resources

Credits for Annual Maintenance

Stormwater Utility Fee credits are available for residential townhome and single-family individual lots with rain gardens and/or bioretention filters and for non-residential and residential condominium properties with bioretention filters. Refer to the credit manual for more information.

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Flow Thru Planter Boxes

Flow thru planter boxes are considered above-ground rain gardens. Like rain gardens, they are micro-bioretention filters that are appropriate for single-family homes and townhouses. Like larger bioretention filters and rain gardens, flow thru planter boxes provide space where runoff can collect during storms.

Planter boxes receive water from downspouts and allow for water to pond 6 to 12 inches above a surface mulch layer. The water then rapidly filters through a mixture of sand, soil, and organic material. Mosquito prevention is achieved when designed correctly so that the ponded water drains within 24-48 hours, which is shorter than needed for mosquito reproduction. Some runoff is taken up by native plants. Plants are selected to tolerate both flooding and drought. Runoff that filters through the soil media in the planter box is discharged through an underdrain that typically returns filtered stormwater to the storm drain system.

flow thru planter box

Design & Installation

Standards for bioretention approved for use in meeting stormwater regulations:

Inspection & Maintenance

Inspection and maintenance should be performed at least annually. Determination of whether a stormwater planter box is properly functioning would include certification of the following:

flow thru planter box checklist

Resources

Credits for Annual Maintenance

Stormwater Utility Fee credits are available for residential townhome and single-family individual lots with flow thru planter boxes and/or bioretention filters and for non-residential and residential condominium properties with bioretention filters, which may also consider planter box configurations. Refer to the credit manual for more information.

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Dry Wells

A dry well is considered a micro-scale infiltration practice per the Virginia BMP Clearinghouse. It temporarily stores runoff underground in the spaces between clean, washed, uniformly-sized stones until the water infiltrates into the soil. Dry wells can only be installed where a soil infiltration test is performed and only when the test indicates an acceptable infiltration rate. Overflow may be connected to a downspout with an overflow to a splash block or connection to the storm drain system. The design, pretreatment (for example: leaf gutter screens), and maintenance requirements vary depending on the area scale of the installation.

Dry Well

Design & Installation

Approved standards:

Inspection & Maintenance

Inspection and maintenance should be performed at least annually. Determination of whether a dry well or other infiltration practice is properly functioning would include certification of the following:

infiltration and dry well checklist

Resources

Credits for Annual Maintenance

Stormwater Utility Fee credits are available for residential townhome, single-family, condominium and non-residential properties with an infiltration practice that was installed meeting the BMP Clearinghouse design specifications. Refer to the credit manual for more information.

  • Residential self-certification form for SWU Flat Credits
  • Certification form for all other Stormwater Utility Fee infiltration practices 

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    Infiltration Trench

    An infiltration trench is considered a small or conventional-scale infiltration practice per the Virginia BMP Clearinghouse. It is applicable for a variety of applications and for example, offers 1) greater volume of runoff infiltrated and treated on-site compared to a French drain and 2) an opportunity to reduce runoff or ponding in a yard area without losing usable space. Infiltration trenches treat runoff from nearly 100% impervious areas by temporarily storing the water underground in the spaces between clean, washed, uniformly-sized stones and allowing it to infiltrate into the soil. Infiltration trenches can only be installed where soil infiltration tests are performed and only when the tests indicate an acceptable infiltration rate. Multiple pretreatment techniques are required.

    infiltration trench

    Design & Installation

    Approved standards:

    Inspection & Maintenance

    Inspection and maintenance should be performed at least annually. Determination of whether a dry well or other infiltration practice is properly functioning would include certification of the following:

    infiltration and dry well checklist

    Resources

    Credits for Annual Maintenance

    Stormwater Utility Fee credits are available for residential townhome, single-family, condominium and non-residential properties with an infiltration practice that was installed meeting the BMP Clearinghouse design specifications. Refer to the credit manual for more information.

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    Permeable Pavement

    Permeable pavement incorporates three elements: 1) a pervious surface option, (i.e., permeable pavers, pervious concrete, porous asphalt, or cellular grid pavers), 2) a stone reservoir, and 3) an underdrain.  

    Permeable Pavement

    Design & Installation

    Approved standards:

    Inspection & Maintenance

    Inspection and maintenance should be performed at least annually. Determination of whether a permeable pavement is properly functioning would include certification of the following:

    permeable pavement checklist

    Resources

    Credits for Annual Maintenance

    Stormwater Utility Fee credits are available for residential townhome and single-family individual lots with permeable pavement systems that have a clean, washed gravel reservoir, as well as for non-residential and residential condominium properties with permeable pavement systems meeting state standards. Note that the Environmental Management Ordinance requires the installation of permeable surfaced driveways in some instances, which do not have a gravel reservoir and are therefore not eligible for stormwater utility fee credits. Refer to the credit manual for more information.

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    Green Roofs

    Vegetated green roofs typically consist of water proofing, drainage materials, an engineered growth media (soil) that is designed to support plant growth, and plants.

    Green Roof Residential

    Design & Installation

    Standards approved for use in meeting stormwater regulations:

    Inspection & Maintenance

    Inspection and maintenance should be performed at least annually. Determination of whether a vegetated green roof is properly functioning would include certification of the following:

    green roof checklist

    Resources

    Credits for Annual Maintenance

    Stormwater Utility Fee credits are available for residential townhome and single-family individual lots with green roofs, as well as for non-residential and residential condominium properties. Refer to the credit manual for more information.

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    Urban Nutrient Management Plans

    Urban Nutrient Management Plans provide a blueprint for proper use of fertilizers, ensuring that excess fertilizers and nutrients – which can harm water quality – are not readily available for transport to the City’s waterways via stormwater runoff.  An urban nutrient management plan is a plan to manage the amount, placement, timing and application of fertilizer, compost, or other materials containing plant nutrients to reduce nutrient loss to the environment and to produce quality turf and landscape plants. Urban Nutrient Management plans must be prepared by a prepared by a Nutrient Management Planner Certified in Turf and Landscape by the Virginia Department of Conservation and Recreation (DCR).  

    Resources

    Credits for Urban Nutrient Management Plans

    Stormwater Utility Fee credits are available for residential condominium properties. Refer to the credit manual for more information.

    Nutrient Management for All Properties

    Properties who are not eligible for credit can still benefit by testing their soil before applying fertilizer. To find out more, visit:

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    Conservation Landscaping 

    Conservation landscaping can be used to reduce polluted runoff by replacing areas of lawn or bare soil in your yard with native plants. Native plants are best suited to minimize runoff and require less nutrient addition or cultivation, reducing nutrient pollution. Conservation landscaping could also include establishing meadow or forested buffers or vegetated filter strips that intercept runoff and protect waterways.

    Conservation Landscaping

    Design & Installation

    Conservation landscaping can be designed to promote co-benefits like providing wildlife habitat and promoting pollinator health.

    Inspection & Maintenance

    Inspection and maintenance should be performed at least annually. Determination of whether a conservation landscaping practice is properly functioning would include certification of the following:

    conservation landscaping checklist

    Resources

    Credits for Annual Maintenance

    Stormwater Utility Fee credits are available for conservation landscaping practices on residential townhouse and single-family individual lots. Refer to the credit manual for more information.

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    New Native Tree Planting

    Tree planting mitigates the stormwater quality impact of impervious and turf land covers in urban areas. Native trees support native pollinators and wildlife, in particular by providing habitat for caterpillars and food for baby birds. Some native trees are better at this than others, especially native oaks and native cherry trees. Plus, shade trees help contribute to meeting the City's canopy coverage goals.

    Native Tree Planting

    Resources:

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