SWM Regulation Public Comment Period Underway
Vol. 19 No. 2

April 4, 2011

Virginia's proposed stormwater management regulations (view a redline version of the regulation) are one step closer to completion, with the Regulatory Advisory Panel (RAP) meeting for a final time on March 9 and the 30-day public comment period beginning on March 28. This public comment period is critical because the proposed regulations differ significantly from the current regulations. It is important for members of the development community to engage their site/civil engineers to evaluate the effect that the new regulations will have on development projects and to provide comments to the Virginia Department of Conservation and Recreation (DCR) prior to April 27, 2011. (Submittal information is provided at the end of this article.)

The quantity control requirements are not expected to significantly increase (±15%) the size of stormwater facilities because the 10-year Flood Protection requirement (which has not changed) is the primary driver of the overall pond size. (Note also that infiltration practices can be used in A and B soils to reduce the pond size requirement.) Typically, the size of the 2-year orifice will be reduced to meet the 1-year Energy Balance requirement, and the 1-year detention volume will typically be greater than the current 2-year volume detention requirement. Therefore, the resulting ponds will be similar in size to those designed under the current regulations, but they will hold water more often, resulting in more efficient downstream protection at a minimal cost. Additionally, the proposed regulations will satisfy adequate outfall requirements (4VAC50-60-66.A).

The proposed quality control requirements, however, are more stringent than current requirements, which will necessitate additional pollutant removal efforts. The degree of additional effort will vary based on land use, soil type, and existing local regulatory requirements (see Field Notes Vol. 17 No. 8); hence, the number or type of additional SWM/BMP facilities can not be easily calculated on a general scale. This is one of the reasons we suggest engaging your site/civil engineers to analyze your development projects.

We have summarized the proposed regulations below:

Grandfathering (4VAC50-60-48)

  • Sites with a VSMP permit issued after July 1, 2009 shall be covered under that permit criteria for an additional two permit cycles. The current (2009) permit expires June 30, 2014, and each subsequent permit is 5 years; therefore, projects may be grandfathered until June 30, 2024.

  • Sites with a land-disturbing activity approved by the locality by July 1, 2012 (and which have a proffered or conditional zoning plan, preliminary, or final subdivision plat, preliminary or final site plan, or zoning with a plan of development that provides SWM layout), but which have not obtained a VSMP permit by July 1, 2014, shall be grandfathered until June 30, 2019.

  • Projects for which there has been an obligation of locality, state, or federal funding prior to July 1, 2012, and for which DCR has approved a stormwater management plan prior to July 1, 2012, shall be grandfathered until June 30, 2019.

  • Projects with issued governmental bonding or public debt financing by July 1, 2012 are grandfathered.

Land-Disturbing Activities Subject to the Chesapeake Bay Preservation Act (4VAC50-60-51)

  • A stormwater plan and an erosion and sediment control plan must be implemented prior to land disturbance, and the project must conduct long-term maintenance of SWM facilities.

Stormwater Pollution Prevention Plans (4VAC50-60-54)
The U.S. Environmental Protection Agency required DCR to include language in the proposed regulation to require implementation of a stormwater pollution prevention plan including, but not limited to, an erosion and sediment control plan (see below), a stormwater management plan (see 4VAC50-60-55), and a pollution prevention plan (see 4VAC50-60-56) for land-disturbing activities associated with the Chesapeake Bay Preservation Act. Erosion and sediment control plans must include the following requirements:

  • Projects must control stormwater volume and velocity to minimize erosion on the site and downstream.

  • Projects must minimize soil exposure, sediment discharges, soil compaction, and the disturbance of steep slopes during construction.

  • Projects must preserve topsoil where feasible and must provide and maintain natural buffers around surface waters, direct stormwater to vegetated areas, and maximize stormwater infiltration.

  • Projects must initiate stabilization of disturbed areas immediately after any earth-disturbing activities have permanently ceased or have temporarily ceased and will not resume for more than 14 calendar days.

One problem with this proposed stormwater pollution prevention plan requirement is that DCR does not define any terms or concepts therein, such as "steep slopes," "controlling stormwater volume," and "maintaining natural buffers." It is debatable whether current erosion and sediment control plans and regulations meet all of the requirements of this section.

Stormwater Management Plans (4VAC50-60-55)

  • A stormwater management plan must be submitted to the stormwater program administrative authority. Stormwater management plans must include:
    • Contributing drainage areas and existing water bodies;
    • Current land use, soil types, and vegetative cover;
    • Adjoining parcel information; and
    • Proposed land use, drainage patterns, limits of clearing and grading, structures, and stormwater management facilities.

Pollution Prevention Plans (4VAC50-60-66)

  • Projects must minimize the discharge of pollutants from equipment wash waters and the exposure of materials to rain events.

Quality Control (4VAC50-60-63)

  • New development must reduce phosphorus loads to 0.41 lb/ac/yr based on the Virginia Runoff Reduction Methodology (which currently does not include a load from forested land but will be changed in the future to do so).

  • Redevelopment projects disturbing one acre or more with no increase in impervious cover must reduce pre-development phosphorus loads by 20%.

  • Redevelopment projects disturbing less than one acre with no increase in impervious cover must reduce pre-development phosphorus loads by 10%.

  • For redevelopment projects that increase impervious cover, the area of new impervious cover shall be subject to the requirements for new development. The remainder of the site shall be subject to the redevelopment criteria above.

  • Linear projects on previously-developed land that increase impervious cover may reduce pre-development phosphorus loads by 20% in lieu of meeting the requirements on new development.

  • The total load shall not be required to be reduced below the standard for new development (unless a locality adopts a more stringent program).

Water Quality Compliance (4VAC50-60-65)

  • Compliance shall be determined by using the Virginia Runoff Reduction Methodology or equivalent.

  • The following BMPs are specifically approved, as are BMPs found at the Virginia Stormwater BMP Clearinghouse Website and those not listed but reviewed and approved by the Director of DCR:


    Vegetated roofs

    Rooftop disconnection

    Rainwater harvesting

    Soil amendments

    Permeable pavement

    Grass channels

    Bioretention

    Infiltration

    Dry swales

    Wet swales

    Sheet flow to a filter or open space

    Extended detention ponds

    Filtering practices

    Constructed wetlands

    Wet ponds

Quantity Control (4VAC50-60-66)

  • Projects conforming to 4VAC50-60-66 shall be deemed to satisfy the requirements of 4VAC50-30-40-19 (Minimum Standard 19 of the Virginia Erosion and Sediment Control Regulations, often referred to as the Adequate Outfall requirement).

  • Projects discharging to manmade conveyance systems must convey the 2-year, 24-hour storm (after SWM) without erosion of the system, or meet the Energy Balance method (see below).

  • Projects discharging to restored conveyance systems must have had the discharge considered in the design of the restored system, or meet the Energy Balance method (see below).

  • Projects discharging to natural conveyance systems must meet the Energy Balance method (see below).

    Energy Balance:

    Qdeveloped≤ I.F. x Qpre-developed x RVpre-developed / RVdeveloped
    Qdeveloped shall not be required to be less than Qforested x RVforested / RVdeveloped
    Qdeveloped must be ≤ Qpre-developed
    Q = Peak runoff flow rate
    RV = Runoff volume
    I.F. = Improvement Factor = 0.8 for sites > 1 ac
                                        = 0.9 for sites ≤ 1 ac

  • Unless the Energy Balance Method is used, conveyance systems shall be analyzed to a point where:
    • The site's contributing drainage area is less than or equal to 1.0 of the total watershed area; or
    • The site's peak flow rate from the one-year, 24-hour storm is less than or equal to 1.0% of the existing peak flow rate from the 1-year, 24-hour storm.

  • Projects discharging concentrated flow to stormwater conveyance systems that do not currently experience localized flooding during the 10-year, 24-hour storm must confine the peak flow rate from the 10-year, 24-hour storm within the conveyance system.

  • Projects discharging concentrated flow to stormwater conveyance systems that currently experience localized flooding during the 10-year, 24-hour storm must confine the peak flow from the 10-year, 24-hour event within the conveyance system or release a post-development peak flow rate (from the 10-year, 24-hour storm) that is less than the predevelopment peak flow rate.

Offsite Compliance Options Include:
An operator may be allowed (by the stormwater program administrative authority) to use the following offsite compliance options to meet the required phosphorus reductions:

  • A comprehensive watershed stormwater management plan for the local watershed within which a project is located;

  • A locality pollutant loading pro rata share program or similar funding mechanism;

  • The nonpoint nutrient offset program established pursuant to 10.1-602.8:1 of the Code of Virginia; or

  • Additional properties belonging to the same operator within the same HUC or upstream HUC or within the same watershed as determined by the stormwater program administrative authority.

  • Operators shall be allowed to utilize offsite options under the following conditions:
    • Less than 5 acres of land will be disturbed;
    • The post-construction phosphorus load control requirement is less than 10 pounds per year; or
    • At least 75% of the required phosphorus reduction will be achieved on-site.

  • Offsite options shall not be allowed when:
    • The selected offsite option does not achieve the necessary nutrient reductions prior to commencement of the operator’s land-disturbing activity; or
    • Local water quality-based limitations (such as those contained in a municipal separate storm sewer system program plan) are exceeded at the point of discharge.

Comments on the proposed regulations may be submitted prior to 5:00 PM, April 27, 2011, via fax to 804-786-6141, via e-mail to regcord@dcr.state.va.us, or via U.S. mail to:

Regulatory Coordinator
Virginia Department of Conservation and Recreation
203 Governor Street, Suite 302
Richmond, Virginia 23219

We anticipate that the Soil and Water Conservation Board (the Board) will adopt the regulations on May 24, with an expected effective date of October 5, 2011. Other notable dates in the approval process include:

May 17 Target date for regulations to be mailed to the Soil and Water Conservation Board
May 24 Board adoption of final regulations
June 20 - August 5 Administrative Review
August 10 Deadline for submittal to registrar for publication
August 29 Publication in the Virginia Registrar and the beginning of the 30-day final adoption period
September 28 30-day final adoption period closes
October 5 Statutory effective date target

For further information on the development of these regulations, see our Field Notes archives:

Vol. 18 No. 9
Vol. 17 No. 8
Vol. 17 No. 7
Vol. 17 No. 6

Questions can be addressed to Mike Rolband, Jen Brophy-Price, or Bethany Bezak.