MS4 Stormwater Management

All tidewater localities and localities with Municipal Separate Storm Sewer System (MS4) permits must regulate and administer stormwater management (runoff volume and water quality) for new development and redevelopment according to the Virginia Stormwater Management Program (VSMP). MS4 permits also establish water quality limits stormwater runoff collected and discharged (to state waters) through the municipal stormwater management (SWM) system of more urbanized areas. A locality’s SWM & water quality requirements are typically found with the zoning ordinance, subdivision ordinance, erosion & sediment control ordinance, Chesapeake Bay ordinance, SWM ordinance, MS4 permits andpolicy documents. SWM efforts to restore hydrologic function to developed lands within the MS4 permitted area can include a variety of green infrastructure practices that protect, restore and work with the natural and nature-based systems that build resiliency into the landscape.

As storm intensity is projected to increase, traditional SWM systems will need to be adapted, to provide more storage, infiltration and treatment of stormwater runoff to minimize flooding and improve water quality. Many localities with traditional SWM systems (culverts, drain pipes, & detention basins) are already experiencing backflow of tidal waters into low-lying pipes and drainage ditches as well as combined sewer overflows. MS4 localities are installing green streets & other green infrastructure practices (e.g. cisterns, rain gardens, bioswales, permeable pavement, bioswales) to control stormwater, reduce flooding and combined sewer overflows and meet water quality goals. In order to meet VSMP water quality and SWM requirements, most new development and redevelopment projects need to use environmental site design techniques and innovative low impact development (LID) or green infrastructure practices.  As water tables rise with sea level rise and high-intensity rainfall events increase, some of these practices may no longer function as designed.

Stafford County: requires LID practices to the maximum extent practicable to meet both water quantity & quality requirements.

James City County: developed a Special Stormwater Criteria policy (SSC) that is applied to new development in protected watersheds. These criteria are more stringent than traditional SWM regulations, with an increased emphasis on site design and source control. Conditions of the criteria can be met if high-priority soils are saved, as to sufficiently maintain the natural recharge of the soil. If natural recharge is impacted, then SSC measures- including the use of on-site BMPs (including rain gardens rain barrels, swales, and pervious pavers), and shared parking agreements, are required.

York County: recently implemented a number of green infrastructure, stream restoration and stormwater retrofit projects in portions of the community subject to recurrent flooding. Instead of simply installing a wet pond, the county stormwater division has created wetlands that store and treat stormwater then slowly release the stormwater to a stream restoration project that included a riparian buffer planting and reconnection of the stream to its floodplain. The projects were funded through the CIP and state stormwater local assistance fund. The newly created marsh areas will be incorporated into local school learning curriculum.

Washington, D.C:  The Water and Sewer Authority has begun issuing environmental impact bonds, an innovative new financing mechanism. Proceeds from the first $25 million bond, sold to private investors, will be used to construct nature-based stormwater management practices in the Rock Creek sewershed. Payments to investors are contingent on the effectiveness of the practices installed, measured in runoff reduction. 

Stafford County Code Sec. 21.5-9. - Technical criteria for regulated land-disturbing activities

(1) Site designs shall minimize the generation of stormwater and maximize pervious areas for stormwater treatment. The use of structural and nonstructural infiltration facilities and low impact development technologies shall be encouraged to provide stormwater quality and quantity control and groundwater recharge.
(2) Natural channel characteristics shall be preserved to the maximum extent practicable.
(5) Stormwater runoff from parking lots shall utilize stormwater management infiltration facilities and/or stormwater management filtering systems.

LID projects eligible through the FEMA Hazard Mitigation Grant Program as a “Minor Localized Flood Reduction” include rain gardens, roadside swales, and infiltration trenches. Vegetative buffers fall under the “soil stabilization” category and can include LID techniques that reduce stream erosion. FEMA policy encourages both green infrastructure and low impact development through their inclusion in a project’s benefit cost analysis, which helps to make these projects more viable.

Many localities fund SWM through a stormwater utility fee and the Capital Improvement plan. Localities can incentivize green infrastructure and on-site stormwater retention through a percent fee reduction for property owners who agree to implement specific GI practices. A one-time credit can also be awarded for the installation of small BMPs, such as rain barrels.

Nonpoint Source Pollution Control Program: administers the CWA 319 grant, which funds projects that reduce NPS pollution and address TMDL requirements.

Virginia Clean Water Revolving Loan Fund Stormwater Loan Program provides funds for local governments to use in the construction of structures and BMPs.

Stormwater Local Assistance Fund: provides funds for stormwater BMPs and stream restoration. Grants range from $100,000-$5,000,000, and recent funding in Virginia has totaled around $23 million annually.

Ex. Hampton using a SLAF grant to retrofit Coliseum Lake (stormwater treatment facility for 362 acre watershed with 80% impervious surface), including changing portion of the lake from open water to wetlands.

Virginia Agricultural BMP cost-share program: provides funds for the voluntary installation of BMPs.

Virginia Conservation Assistance Program: provides reimbursements to property owners for BMP installation, including cistern construction and rain gardens.

National Fish and Wildlife Fund: provides grants and technical assistance through the Chesapeake Bay Stewardship Fund

Stormwater Utility Fees: Ex. Miami-Dade, FL created a stormwater utility fees bond, which fund stormwater infrastructure investments that double as flood mitigation/adaptation.

Localities should require that projects, whenever possible, use green infrastructure to manage runoff on-site. LEED credit can be generated for BMP use, including reforestation, rainwater harvesting, permeable pavement, and constructed wetlands, among others. Localities should require developers to consider sea level rise when siting BMPs, to ensure structures won’t be compromised during their working life. Beyond siting, BMPs need higher levelconstruction standards to protect against intense storm events.

Although localities were required to develop a new stormwater ordinance to comply with the Virginia Stormwater Management Program, localities should consider conducting a thorough code review to ensure that environmental site design and other new stormwater techniques, namely green infrastructure and low impact development, are encouraged for new development and redevelopment. GI/LID should be used to the maximum extent possible on publically-owned lands, and educational and pilot programs should be used to disseminate knowledge to private property owners. To reduce confusion, a locality may consider developing a publication to inform developers of all relevant stormwater regulations. This type of guidance document can also ensure agreement between allordinances.

A common barrier is the complexity of implementing stormwater programs because of overlapping and sometimes conflicting involvement of multiple departments in the land-use decision making process. For example, in our locality interviews, we heard that one department is responsible for overseeing the Bay TMDL, while another department is responsible for conducting watershed studies, and yet another department is responsible for administering the VSMP program for new development, while another department manages existing stormwater facilities and MS4 permit compliance. There is a lack of awareness of what other departments are doing, and actions that have multiple benefits are left unrealized.

One barrier that has often been repeated in locality meetings is the issue of local liability for flood damages. For example, a locality may be hesitant to try and repair a failing stormwater BMP out of concern over liability for future maintenance needs. For more information on local liability, see this white paper from the Virginia Coastal Policy Clinic.

  • Provide one of the largest opportunities to meet TMDL requirements
  • Practices that use environmental site designminimize disturbance and protect natural infrastructure during development result in more resilient landscapes that mimic the natural hydrologic system.
  • Practices that convert impervious surfaces and turf to forested conditions, restore and reconnect streams to their floodplains and/or create wetlands provide the most nutrient and sediment reduction credits possible to meet Chesapeake Bay TMDL and MS4 permit goals while also reducing flooding, restoring critical habitat and increasing the resiliency and adaptive capacity of the landscape.
  • MS4 localities tend to be more urbanized with fewer feasible green infrastructure options and less space to implement those options  
  • Coordinating with multiple stakeholders in different departments is difficult, and achieving multiple benefits of both water quality and quantity are often unrealized.
  • The development community of practice is largely uninformed or trained to plan and implement environmental site design and LID practices on new development to meet new VSMP requirements.
  • Effective SWM requires a dedicated and sustainable source of funding. 
  • Proper maintenance of stormwater BMPs is critical for their continued operation. Common mistakes include mowing wetlands and failing to replant or water vegetation in buffer strips

The Virginia Department of Environmental Quality (DEQ) administers MS4 permits. Within the Commonwealth, all MS4 localities are required to prepare a Chesapeake Bay Total Maximum Daily Load (TMDL) Action Plan, which must be reflected in their MS4 program. This Action Plan must contain both the actions and funding mechanisms that each MS4 community will use to meet the nutrient and sediment load limits established in Phase II of Virginia’s Watershed Implementation Plan (WIP).

MS4 localities and all tidewater localities are required to adopt a Virginia Stormwater Management Program (VSMP), which must include a SWM ordinance regulating land disturbing activities. The VSMP must integrate, as a condition for the approval of new construction and redevelopment plans, local erosion and sediment control, flood insurance and floodplain management and compliance with the Chesapeake Bay Act.

The VSMP promotes the use of low impact development designs, regional and watershed approaches, and nature-based, non-structural means of controlling stormwater. However,

The Program only regulates the stormwater runoff reduction and water quality impacts for new development and redevelopment excluding single family lots with less than an acre of land disturbance. This is especially problematic in developed cities with high residential land use where redevelopment on private properties doesn’t exceed the 1 acre threshold.  In areas subject to the Chesapeake Bay Preservation Act, however, single family residences may be regulated when land disturbance exceeds 2,500 square feet.

With adequate findings from watershed plans or MS4 permit implementation, localities may adopt more stringent ordinances to prevent further degradation of water resources, stream channel erosion, excessive flooding, or depletion of groundwater resources, and to meet TMDL requirements.

A locality may develop comprehensive SWM plans and implement those plans through new development, redevelopment, or community projects.

1: Up to 1,000 points (Activity 530, Flood Protection (FP), Manual pg. 530-6):

Credit for small scale flood control projects that protect insurable buildings, or storage facilities with natural buffers or wetlands.

2: Up to 110 points (Activity 450, Stormwater Management Regulations (SMR), pg. 450-5):

Credit for regulations requiring restrictions on land-disturbing activities over a given size threshold

3: Up to 225 points (Activity 450, Stormwater Management Regulations (SMR), pg. 450-6):

Credit for regulations that plan for stormwater discharge amounts resulting from various sizes of storms.

4: Up to 20 Points (Activity 450, Stormwater Management Regulations (SMR), pg. 450-10):

Credit for regulations that require the maintenance and inspection of stormwater facilities

5: Up to 120 points (Activity 540, Storage Basin Maintenance (SBM), pg. 540-18):

Credit for regulations or policies requiring the annual maintenance of storage basins for stormwater management

6: Up to 350 extra credit points (Activity 420, Natural Functions Open Space (NFOS), pg. 420-13):

Credit for regulations or policies requiring the annual maintenance of storage basins for stormwater management

7: Up to 80 points (Activity 330, Program for Public Information (PPI), pg. 330-12):

Credit for raising public awareness of stormwater issues.

Code of Virginia § 15.2-2114:

Localities can establish a system of service charges to support the local SWM program

Code of Virginia § 62.1-44.15:33:

Localities can adopt more stringent standards in their stormwater management ordinances

9 VAC 25-870-99:

Authorizes the creation of a regional stormwater management plan.

40 CFR §123.25:

Municipal Separate Storm Sewer Management Program (MS4) mandates storm water control.

42 CFR §122.26:

CWA requires municipalities to have a stormwater management plan

Virginia Runoff Reduction Method to determine BMP capacity (Center for Watershed Protection)

National Stormwater Calculator (EPA)

Stormwater Management Handbook (DCR)

Stormwater BMP Clearinghouse: Includes design specifications and standards for approved BMPs in VA

Guidance Document for Chesapeake Bay TMDL Action Plan (DEQ)

Stormwater Management Model Ordinance (DCR)

Guide for Maintaining and Operating BMPs (Chesapeake)

Chesapeake Stormwater Network: Provides tools and regulatory updates for localities

Ambrette, B. and A. W. Whelchel. 2013. Adapting to the Rise: A Guide for Connecticut’s Coastal Communities. The Nature Conservancy, Coastal Resilience Program. Publication 13-5, New Haven, CT.

Atkins. (2015). Flood Loss Avoidance Benefits of Green Infrastructure for Stormwater Management. Environmental Protection Agency, Office of Wetlands, Oceans and Watersheds.

Bitting, J., & Kloss, C. (2008 ). Managing Wet Weather with Green Infrastructure . Low Impact Development Center.

DEQ. (2014). Virginia Nonpoint Source Pollution Management Program Plan. Virginia Department of Environmental Quality, Division of Water.

DEQ. (2015). Virginia’s TMDL Implementation Cost-Share Best Management Practice Guidelines . Virginia Department of Environmental Quality, Office of Watershed Programs, Richmond.

EPA. (2010). Green Infrastructure Case Studies: Municipal Policies for Managing Stormwater with Green Infrastructure . Environmental Protection Agency, Office of Wetlands, Oceans and Watersheds

HRPDC. 2015 Land and Water Quality Protection in Hampton Roads - Phase III

JRA & WEG. (2013). Integrated and Enhanced Stormwater Management & Erosion and Sediment Control. James River Association, Williamsburg Environmental Group.

VA APA. (2014). Managing Growth and Development in Virginia: A Review of the Tools Available to Localities. Virginia Chapter of the American Planning Association.