Title of Regulation: 4VAC50-60. Virginia Stormwater Management Program (VSMP) Permit Regulations (amending 4VAC50-60-10, 4VAC50-60-20, 4VAC50-60-30, 4VAC50-60-40; adding 4VAC50-60-53, 4VAC50-60-56, 4VAC50-60-63, 4VAC50-60-65, 4VAC50-60-66, 4VAC50-60-72, 4VAC50-60-74, 4VAC50-60-76, 4VAC50-60-85, 4VAC50-60-93, 4VAC50-60-96, 4VAC50-60-102, 4VAC50-60-104, 4VAC50-60-106, 4VAC50-60-108, 4VAC50-60-112, 4VAC50-60-114, 4VAC50-60-116, 4VAC50-60-118, 4VAC50-60-122, 4VAC50-60-124, 4VAC50-60-126, 4VAC50-60-128, 4VAC50-60-132, 4VAC50-60-134, 4VAC50-60-136, 4VAC50-60-138, 4VAC50-60-142, 4VAC50-60-154, 4VAC50-60-156, 4VAC50-60-157, 4VAC50-60-158, 4VAC50-60-159; repealing 4VAC50-60-50, 4VAC50-60-60, 4VAC50-60-70, 4VAC50-60-80, 4VAC50-60-90, 4VAC50-60-100, 4VAC50-60-110, 4VAC50-60-120, 4VAC50-60-130, 4VAC50-60-140, 4VAC50-60-150).

Statutory Authority: §§ 10.1-603.2:1 and 10.1-603.4 of the Code of Virginia.

Public Hearing Information:

June 30, 2009 - 7 p.m. - Hungry Mother State Park, Hemlock Haven Conference Center, 380 Hemlock Haven Lane, Marion, VA

July 1, 2009 - 7 p.m. - Augusta County Government Center, Board of Supervisors Meeting Room, 18 Government Center Lane, Verona, VA

July 7, 2009 - 7 p.m. - City of Manassas, City Council Chambers, 9027 Center Street, Manassas, VA

July 9, 2009 - 7 p.m. - City of Hampton, City Council Chambers, 22 Lincoln Street, 8th Floor, Hampton, VA

July 14, 2009 - 7 p.m. - Virginia General Assembly Building, 910 Capitol Street, Senate Room B, Richmond, VA

Public Comments: Public comments may be submitted until 5 p.m. on August 21, 2009.

Agency Contact: David C. Dowling, Policy, Planning, and Budget Director, Department of Conservation and Recreation, 203 Governor Street, Suite 302, Richmond, VA 23219, telephone (804) 786-2291, FAX (804) 786-6141, or email david.dowling@dcr.virginia.gov.

Basis: The Virginia Stormwater Management Program was created by Chapter 372 of the 2004 Virginia Acts of Assembly (HB1177). This action transferred the responsibility for the permitting programs for Municipal Separate Storm Sewers (MS4s) and construction activities from the State Water Control Board and DEQ to the Virginia Soil and Water Conservation Board and Department of Conservation and Recreation. This federally authorized program is administered in accordance with requirements set forth in the federal Clean Water Act (33 USC § 1251 et seq.) as well as the Virginia Stormwater Management Act (§ 10.1-603.1 et seq. of the Code of Virginia).

Subdivision 2 of § 10.1-603.2:1 of the Code of Virginia authorizes the Virginia Soil and Water Conservation Board to delegate to the department or an approved locality the implementation of the Virginia Stormwater Management Program.

Section 10.1-603.3 of the Code of Virginia (as it will read effective July 1, 2009) requires establishment of stormwater management programs by localities. The board must amend, modify, or delete provisions of the Virginia Stormwater Management Program (VSMP) Permit Regulations to allow localities to implement local stormwater management programs.

Additionally, enactment clause 2 of the Chapter 18 of the 2009 Virginia Acts of Assembly stipulates that the regulation that establishes local program criteria and delegation procedures and the water quality and water quantity criteria, and that is referenced in subsections A and B of § 10.1-603.3 of this act, shall not become effective prior to July 1, 2010.

Subsection E of § 10.1-603.3 of the Code of Virginia further stipulates minimum requirements for a local stormwater program.

Section 10.1-603.4 of the Code of Virginia also provides additional authority and guidance to the board in the development of regulations, including authority to develop criteria associated with local program administration and implementation, criteria to control nonpoint source pollution, and establishment of statewide standards for stormwater management from land-disturbing activities. It should also be noted that localities may adopt more stringent criteria than the minimum criteria developed by the board through this regulatory process.

HB 2168 of the 2009 Legislative Session (in a July 1, 2009, effective date) establishes a new § 10.1-603.8:1 of the Code of Virginia containing a process for approving stormwater management offsets in the Chesapeake Bay watershed and grants the board the necessary authority to develop a future program in the remainder of the state.

Also, requirements set forth in the federal Clean Water Act (33 USC § 1251 et seq.), formerly referred to as the Federal Water Pollution Control Act or Federal Water Pollution Control Act Amendments of 1972, P. L. 92-500, as amended by P. L. 95-217, P. L. 95-576, P. L. 96-483, and P. L. 97-117, or any subsequent revisions thereto, and its attendant regulations set forth in 40 CFR Parts 122, 123, 124 and 125 requires states to establish a permitting program for the management of stormwater for municipal separate storm sewer systems (MS4s) and construction activities disturbing greater than or equal to an acre.

Purpose: Controlling stormwater runoff and its impacts is a serious issue facing the Commonwealth and its local governments. Citizens are complaining about flooding caused by increased amounts of stormwater runoff and the runoff is also reported as a contributor to excessive nutrient enrichment in numerous rivers, lakes, and ponds throughout the state, as well as a continued threat to estuarine waters and the Chesapeake Bay. Numerous studies have documented the cumulative effects of urbanization on stream and watershed ecology. Research has established that as impervious cover in a watershed increases, stream stability is reduced, habitat is lost, water quality becomes degraded, and biological diversity decreases largely due to stormwater runoff.

We recognize that impervious areas decrease the natural stormwater purification functions of watersheds and increase the potential for water quality impacts in receiving waters. Additionally, runoff from managed turf is recognized as an additional significant source of pollutants.

Uncontrolled stormwater runoff has many cumulative impacts on humans and the environment including:

• Flooding - Damage to public and private property,

• Eroded Streambanks - Sediment clogs waterways, fills lakes and reservoirs, and kills fish and aquatic animals,

• Widened Stream Channels - Loss of valuable property,

• Aesthetics - Dirty water, trash and debris, foul odors,

• Fish and Aquatic Life - Impaired and destroyed,

• Impaired Recreational Uses - Swimming, fishing, boating,

• Threatens Public Health - Contamination of drinking water, fish/shellfish,

• Threatens Public Safety - Drownings occur in flood waters, and

• Economic Impacts – Impairments to fisheries, shellfish, tourism, and recreation-related businesses.

Additionally, development can dramatically alter the hydrologic regime of a site or watershed as a result of increases in impervious surfaces. The impacts of development on hydrology may include loss of vegetation, resulting in decreased evapotranspiration; soil compaction; reduced groundwater recharge; reduced stream base flow; increased runoff volume; increased peak discharges; decreased runoff travel time; increased frequency and duration of high stream flow; increased flow velocity during storms; and increased frequency of bank-full and over-bank floods.

It is believed that these proposed regulations will work to minimize the cumulative impacts of stormwater on humans and the environment and moderate the associated hydrologic impacts. If not properly managed, stormwater can have significant economic impacts and the stream restoration costs to fix the problems after the fact are very costly.

A 2007 EPA Office of the Inspector General report entitled "Development Growth Outpacing Progress in Watershed Efforts to Restore the Chesapeake Bay"; Report No. 2007-P-00031; September 10, 2007, noted that "new development is increasing nutrient and sediment loads at rates faster than loads are being reduced from developed lands." The Chesapeake Bay Program Office estimated that impervious surfaces in the Bay watershed grew significantly – by 41% – in the 1990s. Meanwhile, the population increased by only 8%. Because progress in reducing loads is being offset by increasing loads from new development, greater reductions will be needed to meet the bay goals as well as to address stream impairments across the Commonwealth. The Chesapeake Bay Program Office estimated that loads from developed and developing lands increased while loads from agriculture and wastewater facilities decreased. Currently, 32% of the phosphorus loads and 28% of the sediment loads to the bay watershed are attributed to urban and suburban sources, making it one of the most significant contributors to the bay's poor health.

The Commonwealth needs to employ all possible strategies in its tool box to address water quality improvements on a statewide basis in both agricultural and urban settings, including making marked improvements in its stormwater regulations. The proposed stormwater regulations are a necessary and critical part of the Commonwealth's overall nutrient reduction strategies and the criteria included in the proposed regulations will slow nutrient and sediment increases, and where possible, contribute to water quality improvements. Improved stormwater management through these regulations will have numerous benefits including reductions in flood risk, avoidance of infrastructure costs through the use of LID practices, improved aquatic life, and enhancement of recreational and commercial fisheries.

This regulatory action is essential to protect the general health, safety, and welfare of the citizens of the Commonwealth from the potential harm of unmanaged stormwater through the establishment of criteria that further protect the quality and manage the quantity of stormwater runoff to state waters, criteria for the administration of a local stormwater management program, processes and procedures for board approval of a qualifying local program, and local program oversight and implementation criteria for the board and the department.

Substance: The key provisions of this regulation:

1. Establish that in order to protect the quality of state waters and to control nonpoint source pollution, a local program shall apply the minimum technical criteria and statewide standards established in Part II for stormwater management associated with land-disturbing activities. In general, since 2005 when the board took over the federal stormwater permit program, the current water quality technical criteria for construction activity statewide are as follows:

• Sites between 0 and 15% imperviousness for new development, all stormwater runoff goes virtually untreated.

• New development above the 16% imperviousness threshold requires a postdevelopment pollutant load of 0.45 lbs/acre/year Phosphorus.

• A 10% reduction in the predevelopment load is required on redevelopment sites.

New statewide water quality technical criteria that are being proposed for construction activity are as follows:

• For new development, a 0.28 lbs/acre/year phosphorus standard is established.

• On prior developed lands, total phosphorus loads shall be reduced to an amount at least 20% below the predevelopment phosphorus load.

• If a wasteload allocation for a pollutant has been established in a TMDL and is assigned to stormwater discharges from a construction activity, control measures must be implemented to meet the WLA.

• A qualifying local program may establish more stringent standards.

• Compliance with the water quality criteria shall be determined utilizing the Virginia Runoff Reduction Method.

• BMPs listed in Table 1 of Part II or those available on the Virginia Stormwater BMP Clearinghouse shall be utilized to reduce the phosphorus load.

• A locality may establish use limitations on specific BMPs (such as wet ponds or certain infiltration practices).

We believe that most projects can achieve the required reductions on site. However, if the water quality technical criteria cannot be met onsite, offsite controls in part or in whole will be allowed by a qualifying local program in accordance with a department-approved comprehensive watershed stormwater management plan. Offsite reductions shall be equal to or greater than those required on the land-disturbing site.

If no comprehensive watershed stormwater management plan exists, the criteria may still be allowed to be met offsite if:

• The local program allows for offsite controls;

• The applicant demonstrates to the satisfaction of the local program that offsite reductions equal to or greater than those that would otherwise be required for the site are achieved;

• The development's runoff will not result in flooding or channel erosion impacts downstream of the site or any offsite treatment area;

• Offsite controls are located within the same Hydrologic Unit Code or the adjacent downstream Hydrologic Unit Code to the land-disturbing site;

• Verification has been received as to the legal right to use the offsite property; and

• A maintenance agreement for the stormwater facilities is developed.

If allowed by the qualifying local program, reductions required for a site may be achieved by the payment of a pro rata fee sufficient to fund improvements necessary to adequately achieve those reductions.

A local program may also waive the water quality requirements through the granting of an exception in accordance with Part III provided that:

• The exception is the minimum necessary to afford relief.

• Reasonable and appropriate conditions are imposed to preserve the intent of the Act.

• Granting will not confer on the permittee any special privileges denied to others under similar circumstances.

• The exception requests are not based upon conditions or circumstances that are self-imposed or self-created.

• Economic hardship alone is not sufficient reason to grant an exception.

Additionally, HB2168 of the 2009 Session, effective July 1, 2009, created a new section numbered 10.1-603.8:1, relating to stormwater nonpoint nutrient offsets that stipulates that a permit-issuing authority may allow compliance with stormwater nonpoint nutrient runoff water quality criteria through the use of the permittee's acquisition of nonpoint nutrient offsets in the same tributary.

2. Establish in Part II water quantity criteria to address channel protection and flood protection. This language clarifies and expands on current requirements found in Minimum Standard 19 in the Erosion and Sediment Control Regulations (4VAC50-30).

Channel protection shall be achieved through one of the following:

• Stormwater released into a manmade conveyance system from the two-year 24-hour storm shall be done so without causing erosion of the system.

• Stormwater released into a restored stormwater conveyance system, in combination with other existing stormwater runoff, shall not exceed the design of the restored system nor result in instability of the system.

• Stormwater released to a stable natural stormwater conveyance shall not cause the system to become unstable from the one-year 24-hour storm discharge and it shall provide a peak flow rate from the one-year 24-hour storm that is less than or equal to the predevelopment peak flow rate as ascertained by the energy balance equation.

• Stormwater released to an unstable natural stormwater conveyance shall provide a peak flow rate from the one-year 24-hour storm that is less than or equal to the forested peak flow rate as ascertained by the energy balance equation.

Flood protection shall be achieved through one of the following:

• The postdevelopment peak flow rate from the 10-year 24-hour storm is confined within a manmade conveyance system.

• The postdevelopment peak flow rate from the 10-year 24-hour storm is confined within a restored stormwater conveyance system.

• The postdevelopment peak flow rate from the 10-year 24-hour storm is confined within a natural stormwater conveyance that currently does not flood.

• The postdevelopment peak flow rate from the 10-year 24-hour storm shall not exceed the predevelopment peak flow rate from the 10-year 24-hour storm based on forested conditions in a natural stormwater conveyance where localized flooding exists.

• A local program may adopt alternative flood design criteria that achieve equivalent results.

If either of the following conditions are met, the channel protection and flood protection criteria do not apply:

• The site's contributing drainage area is less than or equal to one percent of the total watershed area draining to the point of discharge.

• The development of the site results in an increase in the peak flow rate from the one-year 24-hour storm that is less than one percent of the existing peak flow rate from the one-year 24-hour storm generated by the total watershed area draining to the point of discharge.

3. Establish the minimum criteria and ordinance requirements (where applicable) for a board-authorized qualifying local program (Part III A) or for a board-authorized department-administered local stormwater management program (Part III B), which include but are not limited to administration, plan review, issuance of coverage under the General Virginia Stormwater Management Program (VSMP) Permit for Discharges of Stormwater from Construction Activities, inspection, enforcement, reporting, and recordkeeping.

A local program shall provide for the following:

a. Identification of the authority or authorities issuing permit coverage, reviewing plans, approving plans, conducting inspections, and carrying-out enforcement.

b. Any technical criteria differing from those set out in the regulations.

c. Plan submission and approval procedures.

d. Project inspection and monitoring processes.

e. Procedures for long-term inspection and maintenance of stormwater management facilities.

f. Enforcement.

g. An ordinance that incorporates the components outlined in items a through f above is required.

h. A local program shall report specified information to the department.

i. A local program may require performance bonds or other financial surety.

A local program shall require stormwater management plans that include the following elements:

• Location of points of discharge, receiving waters, predevelopment and postdevelopment conditions.

• Contact information.

• Project narrative.

• Location and design of stormwater management facilities.

• Hydrologic characteristics and structural properties of the soils utilized during facility installation.

• Hydrologic and hydraulic computations of the predevelopment and postdevelopment runoff conditions for the required design storms.

• Calculations verifying compliance with the water quality and quantity requirements.

• A site map that includes the specified elements.

• Plans shall be appropriately signed and sealed by a professional.

The regulation establishes timelines for establishing plan and application completeness, for plan review and approval, and for plan modifications. It also establishes applicant notification requirements.

Establish that coverage under the construction general permit shall be authorized in accordance with the following:

• The applicant must have an approved stormwater management plan.

• The applicant must have submitted proposed right-of-entry agreements or easements granted from the owner to the local program for the purposes of inspection and maintenance of stormwater management facilities as well as maintenance agreements, including inspection schedules, for such facilities.

• An approved general permit registration statement.

• The required fee form and total fee.

Inspections shall be conducted as follows:

• The local program or its designee shall inspect the land-disturbing activity during construction.

• At the termination of the project and prior to bond or surety release of the performance bond or surety, construction record drawings for the permanent stormwater facilities shall be submitted to the local program.

• The owner of the stormwater management facilities shall conduct inspections in accordance with the inspection schedule in the recorded maintenance agreement and shall submit the inspection report to the local program.

• The local program shall develop a board-approved inspection schedule.

Information shall be reported on a fiscal year basis by the local program to the department by October 1 annually as follows:

• Information regarding permanent stormwater facilities completed during the fiscal year.

• Number of permitted projects inspected by acreage categories.

• Number and type of enforcement actions taken.

• Number of exceptions granted or denied.

4. Establish a Schedule of Civil Penalties as guidance for a court as required by law.

5. Establish in Part III D the procedures the board will utilize in authorizing a locality to administer a qualifying local program. The application package shall include the following:

• The local program ordinance(s);

• A funding and staffing plan based on the projected permitting fees; and

• The policies and procedures, including but not limited to, agreements with Soil and Water Conservation Districts, adjacent localities, or other entities, for the administration, plan review, permit issuance, inspection and enforcement components of the program.

The department shall operate a program in any locality in which a qualifying local program has not been adopted in accordance with a board-approved schedule.

6. Establish in Part III C the criteria the department will utilize in reviewing a locality's administration of a qualifying local program. The review shall consist of the following:

• An interview between department staff and the qualifying local program administrator or his designee;

• A review of the local ordinance(s) and other applicable documents;

• A review of a subset of the plans approved by the qualifying local program and consistency of application including exceptions granted;

•· An accounting of the receipt and of the expenditure of fees received;

• An inspection of regulated activities; and

• A review of enforcement actions and an accounting of amounts recovered through enforcement actions.

7. Make changes to definitions in Part I by deleting unnecessary definitions; establishing abbreviations for commonly used terms; and adding needed definitions.

Issues: The primary advantage of this proposed regulatory action is enhanced water quality and management of stormwater runoff in the Commonwealth. Citizens are complaining about flooding caused by increased amounts of stormwater runoff and the runoff is also a contributor to excessive nutrient enrichment in numerous rivers, lakes, and ponds throughout the state, as well as a continued threat to estuarine waters and the Chesapeake Bay. The water quality and quantity criteria proposed by this regulatory action will improve upon today's stormwater management program and assist the Commonwealth in reducing nutrient pollution and meeting Chesapeake Bay restoration goals. The regulations will have numerous benefits including reductions in flood risk, avoidance of infrastructure costs through the use of LID practices, improved aquatic life, and enhancement of recreational and commercial fisheries.

The implementation of local stormwater management programs will also have benefits for the regulated community. Today, construction activity operators must go to two sources in order to receive needed Erosion and Sediment Control (locality) and Stormwater (department) approvals. The development of locality-run qualifying local programs will allow for both approvals to be received from a singular source, thus improving efficiency as well as saving time for the developer. Even in localities where the department administers the local stormwater management program, the program envisioned by these proposed regulations will allow for greater customer service and oversight over today's more limited program.

As the board is also proposing a regulatory action related to permit fees (Part XIII) as a compliment to this regulatory action, and as the permit fees proposed by that regulatory action are based on projected costs associated with program administration based on actual data for performing specified management activities, this regulatory action is not projected to have an adverse financial impact upon localities administering qualifying local programs or upon the department in administering local stormwater management programs or in its oversight of qualifying local programs.

The primary disadvantage of this regulatory action will be increased compliance costs in some instances for construction site operators. Those costs are further discussed in the economic impact portion of this document.

The Department of Planning and Budget's Economic Impact Analysis:

Summary of the Proposed Amendments to Regulation. The Virginia Stormwater Management Program was created by Chapter 372 of the 2004 Virginia Acts of Assembly (HB1177). This action transferred the responsibility for the permitting programs for Municipal Separate Storm Sewers (MS4s) and construction activities from the State Water Control Board and the Department of Environmental Quality to the Virginia Soil and Water Conservation Board and the Department of Conservation and Recreation. This federally-authorized program is administered in accordance with requirements set forth in the federal Clean Water Act (33 USC § 1251 et seq.) as well as the Virginia Stormwater Management Act (§ 10.1-603.1 et seq.).

The Virginia Soil and Water Conservation Board (Board), with the assistance of the Virginia Department of Conservation and Recreation (DCR), proposes a comprehensive revision of Virginia's regulations regarding the control and treatment of stormwater runoff from land development activities. The Board proposes to amend the technical criteria applicable to stormwater discharges from construction activities, establishes minimum criteria for locality-administered stormwater management programs (qualifying local programs) and Department of Conservation and Recreation (Department) administered local stormwater management programs, as well as authorization procedures and review procedures for qualifying local programs, and amends the definitions section applicable to all of the Virginia Stormwater Management Program (VSMP) regulations.

With regard to technical criteria applicable to stormwater discharges from construction activities, revised water quality and water quantity requirements are proposed to be included in Part II of the regulations. Water quality requirements include a 0.28 lbs/acre/year phosphorus standard for new development, a requirement that total phosphorus loads be reduced to an amount at least 20% below the predevelopment phosphorus load on prior developed lands, and a requirement that control measures be installed on a site to meet any applicable wasteload allocation. Water quantity requirements include both channel protection and flood protection criteria. This action would also establish the minimum criteria and ordinance requirements (where applicable) for a Virginia Soil and Water Conservation Board (Board) authorized qualifying local program (Part IIIA) or for a Board-authorized Department-administered local stormwater management program (Part IIIB) which include, but are not limited to, administration, plan review, issuance of coverage under the General Virginia Stormwater Management Program (VSMP) Permit for Discharges of Stormwater from Construction Activities, inspection, enforcement, reporting, and recordkeeping. Part IIID establishes the procedures the Board will utilize in authorizing a locality to administer a qualifying local program. Part IIIC establishes the criteria the Department will utilize in reviewing a locality's administration of a qualifying local program.

Finally, this proposed action would make changes to definitions in Part I, which is applicable to the full body of the VSMP regulations. Unnecessary definitions are proposed to be deleted, needed definitions are proposed to be added, and many existing definitions are proposed to be updated.

Note: most of the following analysis was directly taken from a report produced by Professor Kurt Stephenson of Virginia Tech and Bobby Beamer of BBeamer LLC.¹

Result of Analysis. The benefits exceed the costs for one or more proposed changes. The costs likely exceed the benefits for one or more other proposed changes.

Estimated Economic Impact. The Board proposes modifications to the existing stormwater water quantity and quality requirements that will be applied to every land disturbing activity not exempted by state law (§ 10.1-603.8 B).² Land disturbing activity subject to this regulation generally includes disturbances of 2,500 square feet or more in the Chesapeake Bay Preservation Act areas and disturbances of an acre or more elsewhere in the state (with some smaller areas included when a part of a larger common plan of development or sale).

The proposed regulations establish statewide water quality design criteria for land disturbing activities. For new land development projects, water quality plans must be designed so that the total phosphorus load shall not exceed 0.28 pounds per acre per year (4VAC50-60-63). The phosphorus load criterion was derived from Chesapeake Bay Tributary Strategies and reductions needed to achieve Bay-wide nutrient reductions derived from the Chesapeake Bay 2000 Agreement. The 0.28/lb/yr phosphorus design criteria represents the average per acre edge of field loading from agriculture, forest and mixed open land uses (estimated from Chesapeake Bay Program watershed model) if the 2005 tributary strategies input deck was fully implemented (DCR 2008). For development that occurs on prior developed land, the designs must allow for the total phosphorus loads to be reduced by 20% below predevelopment levels. While the Chesapeake Bay Tributary Strategies called for phosphorus reductions exceeding 40%, a lower water quality criteria for redevelopment was chosen 1) to achieve additional load reductions from urban areas over existing regulations, and 2) to avoid higher barriers to redevelopment. No explicit sediment or nitrogen water quality design criteria were established because it was determined that the stormwater management practices used to achieve the necessary phosphorus reductions would also result in reductions of nitrogen, sediment, and other potential pollutants.

Compliance is determined by implementing control practices outlined in 4VAC50-60-65. The revisions provide three general ways to reduce phosphorus loads: 1) managing land use conversion (forest, turf, and impervious cover), 2) reducing runoff volumes, and 3) treatment of stormwater runoff. An initial list of best management practices that can be used to achieve the phosphorus criteria are listed in 4VAC50-60- 65 B. Other BMPs available to comply with the stormwater requirements are listed on the new Virginia Stormwater BMP Clearinghouse website (http://www.vwrrc.vt.edu/swc). The removal efficiency of each BMP includes phosphorus removal from treating the pollutant concentration in the stormwater as well as the percent removal achieved by preventing runoff from occurring (based upon 1 inch of rainfall, 90% storm). The addition of the runoff reduction potential of individual stormwater control practices reflects a substantive change over the existing regulation. Similar to existing practice, the calculation of phosphorus loads is based primarily on the "simple method" (see Virginia Stormwater Handbook) that relates phosphorus load to total impervious surface. The simple method calculation, however, is modified by adding phosphorus loading coefficients for turf and forest land cover. To assist in determining compliance, DCR has also developed an Excel stormwater compliance spreadsheet.

Water quantity control requirements (4VAC50-60-66) establish minimum standards for downstream flood protection and stream channel protection. The proposed regulation establishes different criteria based on the condition of the existing stormwater conveyance systems. Four general classifications of conveyance systems are identified: 1) man-made conveyance systems, 2) restored streams (designed to restore natural steam channels), 3) stable natural stream channels, and 4) unstable natural stream channels. For stream channel protection, general water quantity criteria are (4VAC50-60-66 B):

• Man-made conveyance: stormwater releases following land disturbing activity conveys postdevelopment peak flow from 2-year, 24-hour storm without causing erosion.

• Restored stream channel: runoff following land disturbing activity will not exceed design of the restored stormwater conveyance system or result in instability of that system.

• Stable natural stream channel: will not become unstable as a result of the peak flow from the 1-year, 24-hour storm and provides a developed peak flow rate equal to the pre-developed flow rate times the pre-developed runoff volume divided by the developed runoff volume.

• Unstable natural steam channel: runoff following a land-disturbing activity shall be released into a channel at or below a peak developed flow rate based on the 1-year 24-hour storm where the developed peak flow rate is equal to the peak flow rate from the site in a forested condition times the volume of runoff from the site in a forested condition divided by the developed runoff volume.

For flood protection, general water quantity criteria are (4VAC50-60-66 C):

• Man-made conveyance must confine the post development peak flow rate from the 10-year, 24-hour storm.

• Restored stream channel: Peak flow rate from the 10-year, 24-hour storm following the land disturbance will be confined within the system.

• Natural stream channel that does not currently flood during a 10-year, 24-hour storm: Post development peak flow from the 10-year, 24-hour storm is confined within the system.

• Natural steam channel where localized flooding exists during a 10-year, 24-hour storm: Post development peak flow rate for 10-year, 24-hour storm shall not exceed predevelopment peak flow from the area under forested conditions.

These criteria do not have to be met under certain conditions where the land disturbance is small relative to the size of the drainage area or results in small contributions to overall peak flow (4VAC50-60-66 D). It is also possible that runoff volume reduction achieved through the implementation of water quality control practices would be sufficient to reduce or avoid the need for water quantity controls.

The proposed regulation allows, in certain situations, water quality and quantity objectives to be met offsite from the disturbed site. Section 4VAC50-60-65F and G allow land disturbers to meet water quality criteria off-site. Specifically, the proposed regulations provide that off-site controls "shall achieve the required pollutant reductions either completely off-site in accordance with the plan or in a combination of on-site and off-site controls." In localities with an approved comprehensive watershed management plan (4VAC50-60-96), offset activities can occur within the same Hydrologic Unit Code (HUC)³ or any locally designated watershed. Without such a plan, offsite controls may be allowed, but must be located within the same HUC or adjacent downstream HUC to the land disturbing site (4VAC50-60-65 G 4). In addition, water quantity objectives could also be met offsite if a locality has a Board approved watershed stormwater management plan and equivalent off-site reductions are demonstrated. In areas with approved watershed plans, localities are also permitted to develop a pro rata fee program. Such a program allows land disturbers to pay a per unit fee ($ per pound of P) to meet all or a portion of a regulatory requirement. Fee funds must be used, by Virginia Code requirements (§ 15.2-2243), to fund actions to achieve equivalent results offsite. Local programs administered by DCR would not have fee system and must confine water quality offset activities within, or adjacent to, the impacted HUC. Additionally, the regulations also provide for a request for an exception that may be granted by a local program in accordance with 4VAC50-60-122.

Linear (road) projects are also subject to the water quality and quantity requirements (VAC 50-60-76). Unless exempt from § 10.1-603.8 B, linear development projects shall "control postdevelopment stormwater runoff in accordance with a site-specific stormwater management plan or a comprehensive watershed stormwater management plan developed in accordance with these regulations."

The proposed regulations also require a stormwater management plan for land disturbing activities. The plan applies the water quality and quantity technical criteria to the land disturbance (4VAC50-60-93).

Program Administration and Permitting: The proposed regulation establishes the requirements for local governments that are required to assume the primary authority to administer the provisions of the proposed regulations as well as for those localities that may elect to administer a program (4VAC50-60-104). DCR's aim is to encourage local governments (counties, cities, and towns) that are not required to administer a program to voluntarily assume this responsibility. Local governments developing a qualifying program must administer the stormwater program in accordance with general criteria outlined in Part III A. In general, a local qualifying program must provide:

• technical criteria to be used in the qualifying local program;

• procedures for the submission and approval of stormwater management plans (4VAC50-60-108)

• assessment and collection of fees;

• inspection and monitoring of land disturbing activities (generally 4VAC50-60-114);

• procedures and policy for long-term inspection and maintenance of stormwater facilities (4VAC50-60-124);

• reporting and record keeping (4VAC30-60-126); and

• enforcement (4VAC30-60-116).

If the local government elects not to administer a program, DCR is required to assume the basic responsibilities of program implementation and administration described above (Part III B).

The regulations also define state oversight responsibilities for the Board and DCR. Section 4VAC50-60-159 describes the general procedure and requirements the Board must use for authorizing a locality to administer a stormwater management program. Once a locality is approved to administer a stormwater management program, section 4VAC50-60-157 describes Board oversight of that program. The Board must review all administered stormwater programs a minimum of once every 5 years (including those administered by DCR). The review will generally consist of reviewing approved site development plans, inspection and enforcement activities, and fee accounting practices. The Board is authorized to pursue corrective actions for noncompliant local programs.

Summary of the estimated economic impact

The proposed revisions to Virginia stormwater regulations will likely produce improvements in the condition of receiving waters. The new emphasis on reducing runoff volumes can produce important benefits related to the condition of aquatic habitat by reducing the energy pulses produced during storm events. New water quantity control requirements also provide benefits in terms of additional flood protection and in-stream aquatic protection. Acknowledging and accounting for the runoff reduction potential of many types of stormwater control practices will increase compliance options and increase the effectiveness of state stormwater regulations.

The proposed regulatory revisions also impose more stringent stormwater water quality criteria. The proposed stormwater regulatory revisions will produce additional reductions in phosphorus and other effluent loads produced from urban land conversion (land use change to impervious cover and turf). Achieving additional improvements in the quality of stormwater will impose new costs on land development activities. In development case examples, the new water quality and quantity standards could be achieved on the development site. The cost of incremental reductions in nutrient loads from the application of stormwater controls, however, is high relative to other nutrient removal options. Uncertainties exist over the long-term cost and effectiveness of many stormwater control practices. The cost of achieving additional nutrient reductions in highly urban settings and other areas with site specific constraints is still uncertain but potentially high. The off-site and pro-rata provisions in the regulation offer opportunities to lower costs and enhance benefits to affected watersheds if properly implemented. The total incremental costs to the state of implementing additional stormwater control practices to meet the proposed regulatory changes could not be estimated at this time.

The proposed revisions apply the same water quality and quantity criteria across the entire state. New proposed stormwater water quality criteria was based on estimates of the nutrient reductions needed to achieve reductions called for in the Chesapeake Bay Tributary Strategies. Economic efficiency of the proposed regulation could be improved by applying differential water quality criteria in watersheds across the state based on the relative water quality benefits that can be achieved.

The proposed regulation will produce improvements in the stormwater permitting structure and will strengthen the administrative tools localities need to implement stormwater programs. While the proposed changes will increase the number and type of control practices that can be used, these changes will also increase the sophistication and resources needed for stormwater design and program administration. The greater expected use of smaller scale distributed practices could increase the costs of local stormwater management, particularly in terms of ensuring the long-term maintenance and performance of stormwater control practices over time. The local and state government cost to administer local stormwater programs will increase (rough estimates range between $13 and $17.5 million, but estimates are not final). State agency cost (DCR) for overall program administration will be a minimum of $3 million per year (estimates are not yet final). These costs are expected to be partially to fully covered by additional fees imposed on land disturbing permit applicants.

Further detail on estimated costs and benefits can be found in the Stephenson and Beamer report, which is Appendix C in the Agency Background Document associated with this proposed action.

Businesses and Entities Affected. The general public and businesses throughout the Commonwealth benefit from additional stream channel and flood protection. Commercial and recreational fisheries benefit from improved water quality. Cleaner waters also benefit tourism–based businesses.

The proposed regulation revises water quality and quantity control requirements for land disturbing activities. As such, the proposed regulations will directly impact private land developers, public land developers, businesses, and homeowners. Virginia residents will also likely pay for the higher costs associated with local stormwater program requirements.⁴

Public agencies (such as state colleges and universities, state agencies, and municipalities) involved in public works and construction projects will also be required to comply with these requirements.

The direct expenditures (costs) associated with implementing the proposed stormwater requirements may increase upon the current demand for stormwater design and construction services. The comprehensive nature of the regulations and the additional technical requirements will necessitate the greater use of environmental consultants and engineers to design stormwater plans and oversee the implementation of stormwater practices. Businesses providing construction and earthmoving services will also be impacted.

Localities Particularly Affected. All Virginia localities are significantly affected by the proposed amendments.

Projected Impact on Employment. Since the comprehensive nature of the regulations and the additional technical requirements will necessitate the greater use of environmental consultants and engineers to design stormwater plans and oversee the implementation of stormwater practices, there will likely be more demand for their services and some increase in the value of associated firms.

Effects on the Use and Value of Private Property. Since the comprehensive nature of the regulations and the additional technical requirements will necessitate the greater use of environmental consultants and engineers to design stormwater plans and oversee the implementation of stormwater practices, there will likely be more demand for their services and some increase in the value of associated firms. Cleaner water may also add to the profitability of some commercial fisheries. Also, increased demand for stormwater design and construction services may result higher value in some associated firms.

Private land developers across the state may face increased land development costs associated with these new regulations in many situations. A portion of those costs will be passed down to buyers of newly constructed properties, homeowners and businesses. Although maintenance of stormwater control facilities should be conducted under today's regulations, many commercial property owners and some residential property owners across the state may still face higher long-term costs associated with maintenance of stormwater control facilities because of the potential for the installation of a greater number of these facilities to meet the proposed requirements and higher maintenance costs associated with some types of BMPs. Virginia residents will also likely pay for the higher costs associated with local stormwater program requirements.

Small Businesses: Costs and Other Effects. Numerous small businesses, particularly those involved in aquaculture and tourism, will benefit from improved water quality. Those and other firms will benefit from reduced flooding risk. As mentioned above, stormwater design and construction services and environmental consultants and engineers will likely encounter greater demand for their services.

On the other hand, private land developers will face increased land development costs associated with these amended regulations, and a portion of those costs will be passed down to buyers of newly constructed properties including small businesses.

Small Businesses: Alternative Method that Minimizes Adverse Impact. The proposed revisions apply the same water quality and quantity criteria across the entire state. New proposed stormwater water quality criteria was based on estimates of the nutrient reductions needed to achieve reductions called for in the Chesapeake Bay Tributary Strategies. Economic efficiency of the proposed regulation could be improved by applying differential water quality criteria in watersheds across the state based on the relative water quality benefits that can be achieved. In other words, there are areas of the state where the environmental benefit of a 0.28 lbs/acre/year phosphorus standard for new development is likely significant, and other parts of the Commonwealth where a less stringent standard would not produce a significant adverse impact. The costs for meeting the standard appear to be significant everywhere. Thus, costs could likely be significantly reduced without significantly reducing total benefit by applying differential water quality criteria in watersheds across the state based on the relative water quality benefits that can be achieved.

Real Estate Development Costs. The proposed regulatory revisions impose more stringent stormwater water quality criteria. The proposed stormwater regulatory revisions will produce additional reductions in phosphorus and other effluent loads produced from urban land conversion (land use change to impervious cover and turf). Achieving additional improvements in the quality of stormwater will impose new costs on land development activities.

Legal Mandate. The Department of Planning and Budget (DPB) has analyzed the economic impact of this proposed regulation in accordance with § 2.2-4007.04 of the Administrative Process Act and Executive Order Number 36 (06). Section 2.2-4007.04 requires that such economic impact analyses include, but need not be limited to, the projected number of businesses or other entities to whom the regulation would apply, the identity of any localities and types of businesses or other entities particularly affected, the projected number of persons and employment positions to be affected, the projected costs to affected businesses or entities to implement or comply with the regulation, and the impact on the use and value of private property. Further, if the proposed regulation has adverse effect on small businesses, § 2.2-4007.04 requires that such economic impact analyses include (i) an identification and estimate of the number of small businesses subject to the regulation; (ii) the projected reporting, recordkeeping, and other administrative costs required for small businesses to comply with the regulation, including the type of professional skills necessary for preparing required reports and other documents; (iii) a statement of the probable effect of the regulation on affected small businesses; and (iv) a description of any less intrusive or less costly alternative methods of achieving the purpose of the regulation. The analysis presented above represents DPB's best estimate of these economic impacts

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¹ Stephenson, K. and B. Beamer. December 31, 2008. "Economic Impact Analysis of Revisions to the Virginia Stormwater Regulation."

² Exemptions under this regulation include land disturbing activities generally associated with agricultural, forest, and mining activities (§ 10.1-603.8 B). Road projects may also be exempted if certain minimal impacts can be demonstrated.

³ Hydrologic Unit Code or "HUC" means a watershed unit established in the most recent version of Virginia's 6th Order National Watershed Boundary Dataset. Sixth order HUC range in size from 10,000 to 40,000 acres. See http://www.dcr.virginia.gov/soil_&_water/hu.shtml

⁴ For localities with stormwater utilities, the increase in cost for stormwater control facilities long-term maintenance may be paid for by higher fees. Other localities would have to cover the higher costs through existing local and state revenue sources.

Agency's Response to the Department of Planning and Budget's Economic Impact Analysis. The Department of Conservation and Recreation (DCR) has reviewed the economic impact analysis (EIA) of the Virginia Soil and Water Conservation Board's proposed amendments to Parts I, II, and III of the Virginia Stormwater Management Program (VSMP) Permit Regulations (4VAC50-60) prepared by the Department of Planning and Budget (DPB) and generally concurs with the assessment while offering the following specific observations and or qualifications.

First, DCR agrees with the assertion of DPB that the "proposed revisions to the Virginia stormwater regulation will likely produce improvements in the condition of receiving waters" and that the "revisions will produce additional reductions in phosphorus and other effluent loads produced from urban land conversion (land use change to impervious cover and turf)." DCR notes that these "proposed regulations will work to minimize the cumulative impacts of stormwater on humans and the environment and moderate the associated hydrologic impacts. If not properly managed, stormwater can have significant economic impacts and the stream restoration costs to fix the problems after the fact are very costly." DCR also notes that "[t]he Commonwealth needs to employ all possible strategies in its tool box to address water quality improvements on a statewide basis in both agricultural and urban settings, including making marked improvements in its stormwater regulations. The proposed stormwater regulations are a necessary and critical part of the Commonwealth's overall nutrient reduction strategies and the criteria included in the proposed regulations will slow nutrient and sediment increases, and where possible, contribute to water quality improvements. Improved stormwater management through these regulations will have numerous benefits including reductions in flood risk, avoidance of infrastructure costs through the use of LID practices, improved aquatic life, and enhancement of recreational and commercial fisheries." DCR also notes that a wealth of additional information regarding the potential benefits of this regulatory action are presented in the detailed Agency Statement document (TH-02 form) accompanying this regulatory action.

Second, DCR wants to provide qualifications to DPB's statements regarding the proposed statewide 0.28 pounds per acre per year water quality phosphorus standard. The EIA recognizes that the 0.28 water quality standard that would be imposed by the proposed regulations was calculated based upon the nutrient reductions needed to meet Virginia's Chesapeake Bay goals. The EIA goes on to state that "[e]conomic efficiency of the proposed regulation could be improved by applying differential water quality criteria in watersheds across the state based on the relative water quality benefits that can be achieved." DCR notes that discussions occurred during the development of the proposed regulations surrounding the possibility of setting different water quality standards for the bay and nonbay areas of the Commonwealth, and DCR remains committed to further examining and discussing the appropriate use of this standard as the regulatory process moves forward. In drafting the proposed regulations, however, a statewide standard was believed to have merit for several reasons:

• Stormwater quality is a recognized problem statewide. Impaired waters are not only prevalent in the Chesapeake Bay, but have also been identified throughout the state. Total maximum daily loads have been established on stream segments throughout the state, including nonbay watersheds, to address these impairments. Additionally, studies have reportedly shown that nutrient loadings to Virginia's rivers draining to the Ohio and Mississippi basins may contribute to those basins' hypoxia episodes.

• While the 0.28 lbs/acre/year phosphorus standard was established not only to meet specified bay goals, but also as the target level necessary to minimize nutrient impacts on Virginia's aquatic systems and to maintain the health of aquatic communities.

• Phosphorus is an "indicator pollutant," meaning that targeting its removal will also lead to reductions in nitrogen, sediment, and other potential pollutants that plague the Commonwealth's waters statewide.

• The 0.28 lbs/acre/yr phosphorous load addresses the reductions needed by new development to maintain predevelopment phosphorous loads associated with non-urban land. The end result is "no-net increase" in phosphorous from new development, which helps assure that development will not further impact streams statewide.

• Additionally, stormwater additions to western streams may have even greater impacts due to the greater sensitivity of cold and cool water ecosystems (such as trout streams) to nutrient enrichment, sedimentation, turbidity, and dissolved oxygen reductions. These systems also contain some of Virginia's most ecologically sensitive and rare aquatic communities.

• Establishment of a statewide standard also simplifies and standardizes compliance calculations across jurisdictions, ensuring that no locality has a competitive development advantage and facilitating implementation for both permit applicants and local program administrators.

Third, the EIA observes that "[t]he cost of incremental reductions in nutrient loads from the application of stormwater controls, however, is high relative to other nutrient removal options." It is recognized that, to date, the Commonwealth has focused its efforts on sources that yield reductions at the lowest cost per pound. Efforts employed so far have been successful in helping to address nutrient removal goals for these sources, notably point sources (wastewater treatment and industrial facilities) and agriculture. Achieving the Commonwealth's water quality goals, however, requires that a comprehensive approach of addressing all nutrient pollution sources be utilized. These goals will not be achieved by allowing further degradation in stormwater quality and local receiving waterbodies and attempting to fully mitigate this damage through reductions achieved elsewhere. Moreover, while gains continue to be made in addressing other pollutant sources, contributions from stormwater runoff continue to increase.

Among other sources noted in the Department's Agency Background Document, a 2007 EPA Office of the Inspector General report entitled "Development Growth Outpacing Progress in Watershed Efforts to Restore the Chesapeake Bay"; Report No. 2007-P-00031; September 10, 2007, noted that "new development is increasing nutrient and sediment loads at rates faster than loads are being reduced from developed lands." The Chesapeake Bay Program Office estimated that impervious surfaces in the bay watershed grew significantly – by 41% – in the 1990s. Meanwhile, the population increased by only 8.0%. Because progress in reducing loads is being offset by increasing loads from new development, greater reductions will be needed to meet the bay goals as well as to address stream impairments across the Commonwealth. The Chesapeake Bay Program Office estimated that loads from developed and developing lands increased while loads from agriculture and wastewater facilities decreased. Currently, 32% of the phosphorus loads and 28% of the sediment loads to the bay watershed are attributed to urban and suburban sources, making it one of the most significant contributors to the bay's poor health. In order for the Commonwealth's waters to be adequately protected, this trend cannot continue, and all sources must be addressed.

Finally DCR reiterates that "[t]hese proposed regulations are thus a necessary part of the overall reduction strategies. We believe that a substantial amount of work done to date shows that proper site planning and designing for stormwater controls early in the development process will ease many difficulties involved with requiring appropriate stormwater controls. These improved stormwater regulations are necessary to protect the public interest. For example, stormwater itself is increasingly being recognized as a resource that should be retained on site and used for irrigation, groundwater recharge, and other beneficial uses. On the other hand, damages to aquatic resources, stream channels, and downstream properties from poorly managed stormwater are significant and are difficult to correct if development has taken place without the necessary design controls."

Summary:

The amendments provide technical criteria applicable to stormwater discharges from construction activities; establish minimum criteria for locality-administered stormwater management programs (qualifying local programs) and Department of Conservation and Recreation administered local stormwater management programs, as well as authorization procedures and review procedures for qualifying local programs; and revise the definitions section applicable to all of the Virginia Stormwater Management Program (VSMP) regulations.

With regard to technical criteria applicable to stormwater discharges from construction activities, revised water quality and water quantity requirements are proposed to be included in Part II of the regulations. Water quality requirements include a 0.28 lbs/acre/year phosphorus standard for new development, a requirement that total phosphorus loads be reduced to an amount at least 20% below the predevelopment phosphorus load on prior developed lands, and a requirement that control measures be installed on a site to meet any applicable wasteload allocation are added. Water quantity requirements include both channel protection and flood protection criteria.

This action would also establish the minimum criteria and ordinance requirements (where applicable) for a Virginia Soil and Water Conservation Board authorized qualifying local program (Part III A) or for a board-authorized department-administered local stormwater management program (Part III B) which include, but are not limited to, administration, plan review, issuance of coverage under the General Virginia Stormwater Management Program Permit for Discharges of Stormwater from Construction Activities, inspection, enforcement, reporting, and recordkeeping. Part III D establishes the procedures the board will utilize in authorizing a locality to administer a qualifying local program. Part III C establishes the criteria the department will utilize in reviewing a locality's administration of a qualifying local program.

Finally, this proposed action would make changes to definitions in Part I, which is applicable to the full body of the VSMP regulations. Unnecessary definitions are proposed to be deleted, needed definitions are proposed to be added, and many existing definitions are proposed to be updated.

Part I
Definitions, Purpose, and Applicability

4VAC50-60-10. Definitions.

The following words and terms used in this chapter have the following meanings unless the context clearly indicates otherwise.

"Act" means the Virginia Stormwater Management Act, Article 1.1 (§ 10.1-603.1 et seq.) of Chapter 6 of Title 10.1 of the Code of Virginia.

"Adequate channel" means a channel watercourse or wetland that will convey the designated frequency storm event without overtopping the channel bank nor its banks or causing erosive damage to the channel bed or, banks, or overbank sections of the same.

"Administrator" means the Administrator of the United States Environmental Protection Agency or an authorized representative.

"Applicable standards and limitations" means all state, interstate, and federal standards and limitations to which a discharge or a related activity is subject under the Clean Water Act (CWA) (33 USC § 1251 et seq.) and the Act, including effluent limitations, water quality standards, standards of performance, toxic effluent standards or prohibitions, best management practices, and standards for sewage sludge use or disposal under §§ 301, 302, 303, 304, 306, 307, 308, 403 and 405 of CWA.

"Approval authority" means the Virginia Soil and Water Conservation Board or their designee.

"Approved program" or "approved state" means a state or interstate program that has been approved or authorized by EPA under 40 CFR Part 123 (2000).

"Aquatic bench" means a 10- to 15-foot wide bench around the inside perimeter of a permanent pool that ranges in depth from zero to 12 inches. Vegetated with emergent plants, the bench augments pollutant removal, provides habitats, conceals trash and water level fluctuations, and enhances safety.

"Average land cover condition" means a measure of the average amount of impervious surfaces within a watershed, assumed to be 16%. Note that a locality may opt to calculate actual watershed-specific values for the average land cover condition based upon 4VAC50-60-110.

"Average monthly discharge limitation" means the highest allowable average of daily discharges over a calendar month, calculated as the sum of all daily discharges measured during a calendar month divided by the number of daily discharges measured during that month.

"Average weekly discharge limitation" means the highest allowable average of daily discharges over a calendar week, calculated as the sum of all daily discharges measured during a calendar week divided by the number of daily discharges measured during that week.

"Best management practice (BMP)" or "BMP" means schedules of activities, prohibitions of practices, including both a structural or nonstructural practice, maintenance procedures, and other management practices to prevent or reduce the pollution of surface waters and groundwater systems from the impacts of land-disturbing activities. BMPs also include treatment requirements, operating procedures, and practices to control plant site runoff, spillage or leaks, sludge or waste disposal, or drainage from raw material storage.

"Bioretention basin" means a water quality BMP engineered to filter the water quality volume through an engineered planting bed, consisting of a vegetated surface layer (vegetation, mulch, ground cover), planting soil, and sand bed, and into the in-situ material.

"Bioretention filter" means a bioretention basin with the addition of a sand filter collector pipe system beneath the planting bed.

"Board" means the Virginia Soil and Water Conservation Board.

"Bypass" means the intentional diversion of waste streams from any portion of a treatment facility.

"Channel" means a natural stream or manmade waterway watercourse with defined bed and banks that conducts continuously or periodically flowing water.

"Constructed wetlands" means areas intentionally designed and created to emulate the water quality improvement function of wetlands for the primary purpose of removing pollutants from stormwater.

"Comprehensive stormwater management plan" means a plan, which may be integrated with other land use plans or regulations, that specifies how the water quality and quantity components of stormwater are to be managed on the basis of an entire watershed or a portion thereof. The plan may also provide for the remediation of erosion, flooding, and water quality and quantity problems caused by prior development.

"Construction activity" means any clearing, grading or excavation associated with large construction activity or associated with small construction activity.

"Contiguous zone" means the entire zone established by the United States under Article 24 of the Convention on the Territorial Sea and the Contiguous Zone (37 FR 11906).

"Continuous discharge" means a discharge which occurs without interruption throughout the operating hours of the facility, except for infrequent shutdowns for maintenance, process changes, or other similar activities.

"Control measure" means any best management practice or other method used to prevent or reduce the discharge of pollutants to surface waters.

"Co-operator" means an operator to of a VSMP permit that is only responsible for permit conditions relating to the discharge for which it is the operator.

"CWA" means the federal Clean Water Act (33 USC § 1251 et seq.), formerly referred to as the Federal Water Pollution Control Act or Federal Water Pollution Control Act Amendments of 1972, Public Law 92-500, as amended by Public Law 95-217, Public Law 95-576, Public Law 96-483, and Public Law 97-117, or any subsequent revisions thereto.

"CWA and regulations" means the Clean Water Act (CWA) and applicable regulations promulgated thereunder. For the purposes of this chapter, it includes state program requirements.

"Daily discharge" means the discharge of a pollutant measured during a calendar day or any 24-hour period that reasonably represents the calendar day for purposes of sampling. For pollutants with limitations expressed in units of mass, the daily discharge is calculated as the total mass of the pollutant discharged over the day. For pollutants with limitations expressed in other units of measurement, the daily discharge is calculated as the average measurement of the pollutant over the day.

"Department" means the Department of Conservation and Recreation.

"Development" means a tract of land developed or to be developed as a unit under single ownership or unified control which is to be used for any business or industrial purpose or is to contain three or more residential dwelling units land disturbance and the resulting landform associated with the construction of residential, commercial, industrial, institutional, recreation, transportation, or utility facilities or structures.

"Direct discharge" means the discharge of a pollutant.

"Director" means the Director of the Department of Conservation and Recreation or his designee.

"Discharge," when used without qualification, means the discharge of a pollutant.

"Discharge of a pollutant" means:

1. Any addition of any pollutant or combination of pollutants to surface waters from any point source; or

2. Any addition of any pollutant or combination of pollutants to the waters of the contiguous zone or the ocean from any point source other than a vessel or other floating craft which is being used as a means of transportation.

This definition includes additions of pollutants into surface waters from: surface runoff that is collected or channeled by man; discharges through pipes, sewers, or other conveyances owned by a state, municipality, or other person that do not lead to a treatment works; and discharges through pipes, sewers, or other conveyances, leading into privately owned treatment works. This term does not include an addition of pollutants by any indirect discharger.

"Discharge Monitoring Report" or "DMR" means the form supplied by the department, or an equivalent form developed by the operator and approved by the board, for the reporting of self-monitoring results by operators.

"Draft permit" means a document indicating the board's tentative decision to issue or deny, modify, revoke and reissue, terminate, or reissue a permit. A notice of intent to terminate a permit, and a notice of intent to deny a permit are types of draft permits. A denial of a request for modification, revocation and reissuance, or termination is not a draft permit. A proposed permit is not a draft permit.

"Drainage area" means a land and water area on a land-disturbing site from which runoff flows to a common outlet point.

"Effluent limitation" means any restriction imposed by the board on quantities, discharge rates, and concentrations of pollutants which are discharged from point sources into surface waters, the waters of the contiguous zone, or the ocean.

"Effluent limitations guidelines" means a regulation published by the administrator under § 304(b) of the CWA to adopt or revise effluent limitations.

"Environmental Protection Agency (EPA)" or "EPA" means the United States Environmental Protection Agency.

"Existing permit" means for the purposes of this chapter a permit issued by the permit-issuing authority and currently held by a permit applicant.

"Existing source" means any source that is not a new source or a new discharger.

"Facilities or equipment" means buildings, structures, process or production equipment or machinery that form a permanent part of a new source and that will be used in its operation, if these facilities or equipment are of such value as to represent a substantial commitment to construct. It excludes facilities or equipment used in connection with feasibility, engineering, and design studies regarding the new source or water pollution treatment for the new source.

"Facility or activity" means any VSMP point source or treatment works treating domestic sewage or any other facility or activity (including land or appurtenances thereto) that is subject to regulation under the VSMP program.

"Flood fringe" is the portion of the floodplain outside the floodway, usually associated with standing rather than flowing water, which is covered by floodwater during the 100-year discharge.

"Flooding" means a volume of water that is too great to be confined within the banks or walls of the stream, water body or conveyance system and that overflows onto adjacent lands, thereby causing or threatening damage.

"Floodplain" means any land area adjoining a channel, river, stream, or other water body that is susceptible to being inundated by water. It includes the floodway and flood fringe areas.

"Floodway" means the channel of a river or other watercourse and the adjacent land areas, usually associated with flowing water, that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than one foot or as otherwise designated by the Federal Emergency Management Agency.

"General permit" means a VSMP permit authorizing a category of discharges under the CWA and the Act within a geographical area.

"Grassed swale" means an earthen conveyance system which is broad and shallow with erosion resistant grasses and check dams, engineered to remove pollutants from stormwater runoff by filtration through grass and infiltration into the soil.

"Hazardous substance" means any substance designated under the Code of Virginia and 40 CFR Part 116 (2000) pursuant to § 311 of the CWA.

"Hydrologic Unit Code" or "HUC" means a watershed unit established in the most recent version of Virginia's 6th Order National Watershed Boundary Dataset.

"Illicit discharge" means any discharge to a municipal separate storm sewer that is not composed entirely of stormwater, except discharges pursuant to a VPDES or VSMP permit (other than the VSMP permit for discharges from the municipal separate storm sewer), discharges resulting from fire fighting activities, and discharges identified by and in compliance with 4VAC50-60-1220 C 2.

"Impervious cover" means a surface composed of any material that significantly impedes or prevents natural infiltration of water into soil. Impervious surfaces include, but are not limited to, conventional roofs, buildings, streets, parking areas, and any conventional concrete, asphalt, or compacted gravel surface that is or may become compacted.

"Incorporated place" means a city, town, township, or village that is incorporated under the Code of Virginia.

"Indian country" means (i) all land within the limits of any Indian reservation under the jurisdiction of the United States government, notwithstanding the issuance of any patent, and including rights-of-way running through the reservation; (ii) all dependent Indian communities with the borders of the United States whether within the originally or subsequently acquired territory thereof, and whether within or without the limits of a state; and (iii) all Indian allotments, the Indian titles to which have not been extinguished, including rights-of-way running through the same.

"Indirect discharger" means a nondomestic discharger introducing "pollutants" to a "publicly owned treatment works (POTW)."

"Infiltration facility" means a stormwater management facility that temporarily impounds runoff and discharges it via infiltration through the surrounding soil. While an infiltration facility may also be equipped with an outlet structure to discharge impounded runoff, such discharge is normally reserved for overflow and other emergency conditions. Since an infiltration facility impounds runoff only temporarily, it is normally dry during nonrainfall periods. Infiltration basin, infiltration trench, infiltration dry well, and porous pavement shall be considered infiltration facilities.

"Inspection" means an on-site review of the project's compliance with the permit, the local stormwater management program, and any applicable design criteria, or an on-site review to obtain information or conduct surveys or investigations necessary in the enforcement of the Act and this chapter.

"Interstate agency" means an agency of two or more states established by or under an agreement or compact approved by Congress, or any other agency of two or more states having substantial powers or duties pertaining to the control of pollution as determined and approved by the administrator under the CWA and regulations.

"Karst features" means sinkholes, sinking and losing streams, caves, large flow springs, and other such landscape features found in karst areas.

"Land disturbance" or "land-disturbing activity" means a manmade change to the land surface that potentially changes its runoff characteristics including any clearing, grading, or excavation associated with a construction activity regulated pursuant to the federal Clean Water Act CWA, the Act, and this chapter.

"Large construction activity" means construction activity including clearing, grading and excavation, except operations that result in the disturbance of less than five acres of total land area. Large construction activity also includes the disturbance of less than five acres of total land area that is a part of a larger common plan of development or sale if the larger common plan will ultimately disturb five acres or more.

"Large municipal separate storm sewer system" means all municipal separate storm sewers that are either:

1. Located in an incorporated place with a population of 250,000 or more as determined by the 1990 decennial census by the Bureau of Census (40 CFR Part 122 Appendix F (2000));

2. Located in the counties listed in 40 CFR Part 122 Appendix H (2000), except municipal separate storm sewers that are located in the incorporated places, townships or towns within such counties;

3. Owned or operated by a municipality other than those described in subdivision 1 or 2 of this definition and that are designated by the board as part of the large or medium municipal separate storm sewer system due to the interrelationship between the discharges of the designated storm sewer and the discharges from municipal separate storm sewers described under subdivision 1 or 2 of this definition. In making this determination the board may consider the following factors:

a. Physical interconnections between the municipal separate storm sewers;

b. The location of discharges from the designated municipal separate storm sewer relative to discharges from municipal separate storm sewers described in subdivision 1 of this definition;

c. The quantity and nature of pollutants discharged to surface waters;

d. The nature of the receiving surface waters; and

e. Other relevant factors.

4. The board may, upon petition, designate as a large municipal separate storm sewer system, municipal separate storm sewers located within the boundaries of a region defined by a stormwater management regional authority based on a jurisdictional, watershed, or other appropriate basis that includes one or more of the systems described in this definition.

"Linear development project" means a land-disturbing activity that is linear in nature such as, but not limited to, (i) the construction of electric and telephone utility lines, and natural gas pipelines; (ii) construction of tracks, rights-of-way, bridges, communication facilities and other related structures of a railroad company; and (iii) highway construction projects.

"Local stormwater management program" or "local program" means a statement of the various methods employed by a locality or the department to manage the quality and quantity of runoff resulting from land-disturbing activities and shall include such items as local ordinances, permit requirements, policies and guidelines, technical materials, plan review, inspection, enforcement, and evaluation consistent with the Act and this chapter. The ordinance shall include provisions to require the control of after-development stormwater runoff rate of flow, the proper maintenance of stormwater management facilities, and minimum administrative procedures.

"Locality" means a county, city, or town.

"Major facility" means any VSMP facility or activity classified as such by the regional administrator in conjunction with the board.

"Major modification" means, for the purposes of this chapter, the modification or amendment of an existing permit before its expiration that is not a minor modification as defined in this regulation.

"Major municipal separate storm sewer outfall (or major outfall)" or "major outfall" means a municipal separate storm sewer outfall that discharges from a single pipe with an inside diameter of 36 inches or more or its equivalent (discharge from a single conveyance other than circular pipe which is associated with a drainage area of more than 50 acres); or for municipal separate storm sewers that receive stormwater from lands zoned for industrial activity (based on comprehensive zoning plans or the equivalent), with an outfall that discharges from a single pipe with an inside diameter of 12 inches or more or from its equivalent (discharge from other than a circular pipe associated with a drainage area of two acres or more).

"Manmade" means constructed by man.

"Manmade stormwater conveyance system" means a pipe, ditch, vegetated swale, or other conveyance constructed by man.

"Maximum daily discharge limitation" means the highest allowable daily discharge.

"Maximum extent practicable" or "MEP" means the technology-based discharge standard for municipal separate storm sewer systems established by CWA § 402(p). MEP is achieved, in part, by selecting and implementing effective structural and nonstructural best management practices (BMPs) and rejecting ineffective BMPs and replacing them with effective best management practices (BMPs). MEP is an iterative standard, which evolves over time as urban runoff management knowledge increases. As such, the operator's MS4 program must continually be assessed and modified to incorporate improved programs, control measures, BMPs, etc., to attain compliance with water quality standards.

"Medium municipal separate storm sewer system" means all municipal separate storm sewers that are either:

1. Located in an incorporated place with a population of 100,000 or more but less than 250,000 as determined by the 1990 decennial census by the Bureau of Census (40 CFR Part 122 Appendix G (2000));

2. Located in the counties listed in 40 CFR Part 122 Appendix I (2000), except municipal separate storm sewers that are located in the incorporated places, townships or towns within such counties;

3. Owned or operated by a municipality other than those described in subdivision 1 or 2 of this definition and that are designated by the board as part of the large or medium municipal separate storm sewer system due to the interrelationship between the discharges of the designated storm sewer and the discharges from municipal separate storm sewers described under subdivision 1 or 2 of this definition. In making this determination the board may consider the following factors:

a. Physical interconnections between the municipal separate storm sewers;

b. The location of discharges from the designated municipal separate storm sewer relative to discharges from municipal separate storm sewers described in subdivision 1 of this definition;

c. The quantity and nature of pollutants discharged to surface waters;

d. The nature of the receiving surface waters; or

e. Other relevant factors.

4. The board may, upon petition, designate as a medium municipal separate storm sewer system, municipal separate storm sewers located within the boundaries of a region defined by a stormwater management regional authority based on a jurisdictional, watershed, or other appropriate basis that includes one or more of the systems described in subdivisions 1, 2 and 3 of this definition.

"Minor modification" means, for the purposes of this chapter, minor modification or amendment of an existing permit before its expiration as specified in 4VAC50-60-640. Minor modification for the purposes of this chapter also means other modifications and amendments not requiring extensive review and evaluation including, but not limited to, changes in EPA promulgated test protocols, increasing monitoring frequency requirements, changes in sampling locations, and changes to compliance dates within the overall compliance schedules. A minor permit modification or amendment does not substantially alter permit conditions, substantially increase or decrease the amount of surface water impacts, increase the size of the operation, or reduce the capacity of the facility to protect human health or the environment.

"Municipal separate storm sewer" means a conveyance or system of conveyances otherwise known as a municipal separate storm sewer system, including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, manmade channels, or storm drains:

1. Owned or operated by a federal, state, city, town, county, district, association, or other public body, created by or pursuant to state law, having jurisdiction or delegated authority for erosion and sediment control and stormwater management, or a designated and approved management agency under § 208 of the CWA that discharges to surface waters;

2. Designed or used for collecting or conveying stormwater;

3. That is not a combined sewer; and

4. That is not part of a publicly owned treatment works.

"Municipal separate storm sewer system" or "MS4" means all separate storm sewers that are defined as "large" or "medium" or "small" municipal separate storm sewer systems or designated under 4VAC50-60-380 A 1.

"Municipal Separate Storm Sewer System Management Program" or "MS4 Program" means a management program covering the duration of a permit for a municipal separate storm sewer system that includes a comprehensive planning process that involves public participation and intergovernmental coordination, to reduce the discharge of pollutants to the maximum extent practicable, to protect water quality, and to satisfy the appropriate water quality requirements of the CWA and regulations and the Virginia Stormwater Management Act and attendant regulations, using management practices, control techniques, and system, design and engineering methods, and such other provisions that are appropriate.

"Municipality" means a city, town, county, district, association, or other public body created by or under state law and having jurisdiction over disposal of sewage, industrial wastes, or other wastes, or an Indian tribe or an authorized Indian tribal organization, or a designated and approved management agency under § 208 of the CWA.

"National Pollutant Discharge Elimination System (NPDES)" or "NPDES" means the national program for issuing, modifying, revoking and reissuing, terminating, monitoring and enforcing permits, and imposing and enforcing pretreatment requirements under §§ 307, 402, 318, and 405 of the CWA. The term includes an approved program.

"Natural channel design concepts" means the utilization of engineering analysis and fluvial geomorphic processes to create, rehabilitate, restore, or stabilize an open conveyance system for the purpose of creating or recreating a stream that conveys its bankfull storm event within its banks and allows larger flows to access its floodplain.

"Natural stormwater conveyance system" means the main channel of a natural stream, in combination with the floodway and flood fringe, which compose the floodplain.

"Natural stream" means a tidal or nontidal watercourse that is part of the natural topography. It usually maintains a continuous or seasonal flow during the year and is characterized as being irregular in cross-section with a meandering course. Constructed channels such as drainage ditches or swales shall not be considered natural streams.

"New discharger" means any building, structure, facility, or installation:

1. From which there is or may be a discharge of pollutants;

2. That did not commence the discharge of pollutants at a particular site prior to August 13, 1979;

3. Which is not a new source; and

4. Which has never received a finally effective VPDES or VSMP permit for discharges at that site.

This definition includes an indirect discharger that commences discharging into surface waters after August 13, 1979. It also includes any existing mobile point source (other than an offshore or coastal oil and gas exploratory drilling rig or a coastal oil and gas developmental drilling rig) such as a seafood processing rig, seafood processing vessel, or aggregate plant, that begins discharging at a site for which it does not have a permit; and any offshore or coastal mobile oil and gas exploratory drilling rig or coastal mobile oil and gas developmental drilling rig that commences the discharge of pollutants after August 13, 1979.

"New permit" means, for the purposes of this chapter, a permit issued by the permit-issuing authority to a permit applicant that does not currently hold and has never held a permit of that type, for that activity, at that location.

"New source," means any building, structure, facility, or installation from which there is or may be a discharge of pollutants, the construction of which commenced:

1. After promulgation of standards of performance under § 306 of the CWA that are applicable to such source; or

2. After proposal of standards of performance in accordance with § 306 of the CWA that are applicable to such source, but only if the standards are promulgated in accordance with § 306 of the CWA within 120 days of their proposal.

"Nonpoint source pollution" means pollution such as sediment, nitrogen and phosphorous, hydrocarbons, heavy metals, and toxics whose sources cannot be pinpointed but rather are washed from the land surface in a diffuse manner by stormwater runoff.

"Nonpoint source pollutant runoff load" or "pollutant discharge" means the average amount of a particular pollutant measured in pounds per year, delivered in a diffuse manner by stormwater runoff.

"Operator" means the owner or operator of any facility or activity subject to regulation under the VSMP program. In the context of stormwater associated with a large or small construction activity, operator means any person associated with a construction project that meets either of the following two criteria: (i) the person has direct operational control over construction plans and specifications, including the ability to make modifications to those plans and specifications or (ii) the person has day-to-day operational control of those activities at a project that are necessary to ensure compliance with a stormwater pollution prevention plan for the site or other permit conditions (i.e., they are authorized to direct workers at a site to carry out activities required by the stormwater pollution prevention plan or comply with other permit conditions). In the context of stormwater discharges from Municipal Separate Storm Sewer Systems (MS4s), operator means the operator of the regulated MS4 system.

"Outfall" means, when used in reference to municipal separate storm sewers, a point source at the point where a municipal separate storm sewer discharges to surface waters and does not include open conveyances connecting two municipal separate storm sewers, or pipes, tunnels or other conveyances which connect segments of the same stream or other surface waters and are used to convey surface waters.

"Overburden" means any material of any nature, consolidated or unconsolidated, that overlies a mineral deposit, excluding topsoil or similar naturally occurring surface materials that are not disturbed by mining operations.

"Owner" means the Commonwealth or any of its political subdivisions including, but not limited to, sanitation district commissions and authorities, and any public or private institution, corporation, association, firm or company organized or existing under the laws of this or any other state or country, or any officer or agency of the United States, or any person or group of persons acting individually or as a group that owns, operates, charters, rents, or otherwise exercises control over or is responsible for any actual or potential discharge of sewage, industrial wastes, or other wastes or pollutants to state waters, or any facility or operation that has the capability to alter the physical, chemical, or biological properties of state waters in contravention of § 62.1-44.5 of the Code of Virginia, the Act and this chapter.

"Peak flow rate" means the maximum instantaneous flow from a prescribed design storm at a particular location.

"Percent impervious" means the impervious area within the site divided by the area of the site multiplied by 100.

"Permit" means an approval issued by the permit-issuing authority for the initiation of a land-disturbing activity or for stormwater discharges from an MS4. Permit does not include any permit that has not yet been the subject of final permit-issuing authority action, such as a draft permit or a proposed permit.

"Permit-issuing authority" means the board, the department, or a locality that is delegated authority by the board to issue, deny, revoke, terminate, or amend stormwater permits under the provisions of the Act and this chapter with a qualifying local program.

"Permittee" means the person or locality to which the permit is issued, including any operator whose construction site is covered under a construction general permit.

"Person" means any individual, corporation, partnership, association, state, municipality, commission, or political subdivision of a state, governmental body (including but not limited to a federal, state, or local entity), any interstate body or any other legal entity.

"Planning area" means a designated portion of the parcel on which the land development project is located. Planning areas shall be established by delineation on a master plan. Once established, planning areas shall be applied consistently for all future projects.

"Point of discharge" means a location at which stormwater runoff is released.

"Point source" means any discernible, confined, and discrete conveyance including, but not limited to, any pipe, ditch, channel, tunnel, conduit, well, discrete fissure, container, rolling stock, concentrated animal feeding operation, landfill leachate collection system, vessel, or other floating craft from which pollutants are or may be discharged. This term does not include return flows from irrigated agriculture or agricultural stormwater runoff.

"Pollutant" means dredged spoil, solid waste, incinerator residue, filter backwash, sewage, garbage, sewage sludge, munitions, chemical wastes, biological materials, radioactive materials (except those regulated under the Atomic Energy Act of 1954, as amended (42 USC § 2011 et seq.)), heat, wrecked or discarded equipment, rock, sand, cellar dirt and industrial, municipal, and agricultural waste discharged into water. It does not mean:

1. Sewage from vessels; or

2. Water, gas, or other material that is injected into a well to facilitate production of oil or gas, or water derived in association with oil and gas production and disposed of in a well if the well used either to facilitate production or for disposal purposes is approved by the board and if the board determines that the injection or disposal will not result in the degradation of ground or surface water resources.

"Pollutant discharge" means the average amount of a particular pollutant measured in pounds per year or other standard reportable unit as appropriate, delivered in a diffuse manner by stormwater runoff.

"Pollution" means such alteration of the physical, chemical or biological properties of any state waters as will or is likely to create a nuisance or render such waters (a) harmful or detrimental or injurious to the public health, safety or welfare, or to the health of animals, fish or aquatic life; (b) unsuitable with reasonable treatment for use as present or possible future sources of public water supply; or (c) unsuitable for recreational, commercial, industrial, agricultural, or other reasonable uses, provided that (i) an alteration of the physical, chemical, or biological property of state waters, or a discharge or deposit of sewage, industrial wastes or other wastes to state waters by any owner which by itself is not sufficient to cause pollution, but which, in combination with such alteration of or discharge or deposit to state waters by other owners, is sufficient to cause pollution; (ii) the discharge of untreated sewage by any owner into state waters; and (iii) contributing to the contravention of standards of water quality duly established by the State Water Control Board, are "pollution" for the terms and purposes of this chapter.

"Post-development" "Postdevelopment" refers to conditions that reasonably may be expected or anticipated to exist after completion of the land development activity on a specific site or tract of land.

"Pre-development" "Predevelopment" refers to the conditions that exist at the time that plans for the land development of a tract of land are approved by submitted to the plan approval authority. Where phased development or plan approval occurs (preliminary grading, roads and utilities, etc.), the existing conditions at the time prior to the first item being approved or permitted submitted shall establish pre-development predevelopment conditions.

"Prior developed lands" means land that has been previously utilized for residential, commercial, industrial, institutional, recreation, transportation or utility facilities or structures, and that will have the impervious areas associated with those uses altered during a land-disturbing activity.

"Privately owned treatment works (PVOTW)" or "PVOTW" means any device or system that is (i) used to treat wastes from any facility whose operator is not the operator of the treatment works and (ii) not a POTW.

"Proposed permit" means a VSMP permit prepared after the close of the public comment period (and, when applicable, any public hearing and administrative appeals) that is sent to EPA for review before final issuance. A proposed permit is not a draft permit.

"Publicly owned treatment works (POTW)" or "POTW" means a treatment works as defined by § 212 of the CWA that is owned by a state or municipality (as defined by § 502(4) of the CWA). This definition includes any devices and systems used in the storage, treatment, recycling, and reclamation of municipal sewage or industrial wastes of a liquid nature. It also includes sewers, pipes, and other conveyances only if they convey wastewater to a POTW treatment plant. The term also means the municipality as defined in § 502(4) of the CWA, that has jurisdiction over the indirect discharges to and the discharges from such a treatment works.

"Qualifying local stormwater management program" or "qualifying local program" means a local program that is administered by a locality that has been authorized by the board to issue coverage under the VSMP General Permit for Discharges of Stormwater from Construction Activities (4VAC50-60-1170).

"Recommencing discharger" means a source that recommences discharge after terminating operations.

"Regional administrator" means the Regional Administrator of Region III of the Environmental Protection Agency or the authorized representative of the regional administrator.

"Regional (watershed-wide) stormwater management facility" or "regional facility" means a facility or series of facilities designed to control stormwater runoff from a specific watershed, although only portions of the watershed may experience land development.

"Regional (watershed-wide) stormwater management plan" or "regional plan" means a document containing material describing how runoff from open space, existing development and future planned development areas within a watershed will be controlled by coordinated design and implementation of regional stormwater management facilities.

"Restored stormwater conveyance system" means a stormwater conveyance system that has been designed and constructed using natural channel design concepts, including the main channel, floodway, and flood fringe.

"Revoked permit" means, for the purposes of this chapter, an existing permit that is terminated by the board before its expiration.

"Runoff coefficient" means the fraction of total rainfall that will appear at a conveyance as runoff.

"Runoff" or "stormwater runoff" means that portion of precipitation that is discharged across the land surface or through conveyances to one or more waterways.

"Sand filter" means a contained bed of sand that acts to filter the first flush of runoff. The runoff is then collected beneath the sand bed and conveyed to an adequate discharge point or infiltrated into the in-situ soils.

"Runoff characteristics" include, but are not limited to, velocity, peak flow rate, volume, time of concentration, and flow duration, and their influence on channel morphology including sinuosity, channel cross-sectional area, and channel slope.

"Runoff volume" means the volume of water that runs off the site of a land-disturbing activity from a prescribed design storm.

"Schedule of compliance" means a schedule of remedial measures included in a permit, including an enforceable sequence of interim requirements (for example, actions, operations, or milestone events) leading to compliance with the Act, the CWA and regulations.

"Secretary" means the Secretary of the Army, acting through the Chief of Engineers.

"Severe property damage" means substantial physical damage to property, damage to the treatment facilities that causes them to become inoperable, or substantial and permanent loss of natural resources that can reasonably be expected to occur in the absence of a bypass. Severe property damage does not mean economic loss caused by delays in production.

"Shallow marsh" means a zone within a stormwater extended detention basin that exists from the surface of the normal pool to a depth of six to 18 inches, and has a large surface area and, therefore, requires a reliable source of baseflow, groundwater supply, or a sizeable drainage area, to maintain the desired water surface elevations to support emergent vegetation.

"Significant materials" means, but is not limited to: raw materials; fuels; materials such as solvents, detergents, and plastic pellets; finished materials such as metallic products; raw materials used in food processing or production; hazardous substances designated under § 101(14) of CERCLA (42 USC § 9601(14)); any chemical the facility is required to report pursuant to § 313 of Title III of SARA (42 USC § 11023); fertilizers; pesticides; and waste products such as ashes, slag and sludge that have the potential to be released with stormwater discharges.

"Single jurisdiction" means, for the purposes of this chapter, a single county or city. The term county includes incorporated towns which are part of the county.

"Site" means the land or water area where any facility or activity is physically located or conducted, a parcel of land being developed, or a designated planning area of a parcel in which the land development project is located. Areas channelward of mean low water in tidal Virginia shall not be considered part of a site.

"Site hydrology" means the movement of water on, across, through and off the site as determined by parameters including, but not limited to, soil types, soil permeability, vegetative cover, seasonal water tables, slopes, land cover, and impervious cover.

"Small construction activity" means:

1. Construction activities including clearing, grading, and excavating that results in land disturbance of equal to or greater than one acre, or equal to or greater than 2,500 square feet in all areas of the jurisdictions designated as subject to the Chesapeake Bay Preservation Area Designation and Management Regulations adopted pursuant to the Chesapeake Bay Preservation Act, and less than five acres. Small construction activity also includes the disturbance of less than one acre of total land area that is part of a larger common plan of development or sale if the larger common plan will ultimately disturb equal to or greater than one and less than five acres. Small construction activity does not include routine maintenance that is performed to maintain the original line and grade, hydraulic capacity, or original purpose of the facility. The board may waive the otherwise applicable requirements in a general permit for a stormwater discharge from construction activities that disturb less than five acres where stormwater controls are not needed based on a "total maximum daily load" (TMDL) approved or established by EPA that addresses the pollutant(s) of concern or, for nonimpaired waters that do not require TMDLs, an equivalent analysis that determines allocations for small construction sites for the pollutant(s) of concern or that determines that such allocations are not needed to protect water quality based on consideration of existing in-stream concentrations, expected growth in pollutant contributions from all sources, and a margin of safety. For the purpose of this subdivision, the pollutant(s) of concern include sediment or a parameter that addresses sediment (such as total suspended solids, turbidity or siltation) and any other pollutant that has been identified as a cause of impairment of any water body that will receive a discharge from the construction activity. The operator must certify to the board that the construction activity will take place, and stormwater discharges will occur, within the drainage area addressed by the TMDL or equivalent analysis.

2. Any other construction activity designated by the either the board or the EPA regional administrator, based on the potential for contribution to a violation of a water quality standard or for significant contribution of pollutants to surface waters.

"Small municipal separate storm sewer system" or "small MS4" means all separate storm sewers that are (i) owned or operated by the United States, a state, city, town, borough, county, parish, district, association, or other public body (created by or pursuant to state law) having jurisdiction over disposal of sewage, industrial wastes, stormwater, or other wastes, including special districts under state law such as a sewer district, flood control district or drainage district, or similar entity, or an Indian tribe or an authorized Indian tribal organization, or a designated and approved management agency under § 208 of the CWA that discharges to surface waters and (ii) not defined as "large" or "medium" municipal separate storm sewer systems or designated under 4VAC50-60-380 A 1. This term includes systems similar to separate storm sewer systems in municipalities, such as systems at military bases, large hospital or prison complexes, and highway and other thoroughfares. The term does not include separate storm sewers in very discrete areas, such as individual buildings.

"Source" means any building, structure, facility, or installation from which there is or may be a discharge of pollutants.

"Stable" means, in the context of channels, a channel that has developed an established dimension, pattern, and profile such that over time, these features are maintained.

"State" means the Commonwealth of Virginia.

"State/EPA agreement" means an agreement between the regional administrator and the state that coordinates EPA and state activities, responsibilities and programs including those under the CWA and the Act.

"State project" means any land development project that is undertaken by any state agency, board, commission, authority or any branch of state government, including state-supported institutions of higher learning.

"State Water Control Law" means Chapter 3.1 (§ 62.1-44.2 et seq.) of Title 62.1 of the Code of Virginia.

"State waters" means all water, on the surface and under the ground, wholly or partially within or bordering the Commonwealth or within its jurisdiction, including wetlands.

"Stormwater" means precipitation that is discharged across the land surface or through conveyances to one or more waterways and that may include stormwater runoff, snow melt runoff, and surface runoff and drainage.

"Stormwater conveyance system" means any of the following, either within or downstream of the land-disturbing activity: (i) a manmade stormwater conveyance system, (ii) a natural stormwater conveyance system, or (iii) a restored stormwater conveyance system.

"Stormwater detention basin" or "detention basin" means a stormwater management facility that temporarily impounds runoff and discharges it through a hydraulic outlet structure to a downstream conveyance system. While a certain amount of outflow may also occur via infiltration through the surrounding soil, such amounts are negligible when compared to the outlet structure discharge rates and are, therefore, not considered in the facility's design. Since a detention facility impounds runoff only temporarily, it is normally dry during nonrainfall periods.

"Stormwater discharge associated with construction activity" means a discharge of pollutants in stormwater runoff from areas where land-disturbing activities (e.g., clearing, grading, or excavation); construction materials or equipment storage or maintenance (e.g., fill piles, borrow area, concrete truck washout, fueling); or other industrial stormwater directly related to the construction process (e.g., concrete or asphalt batch plants) are located.

"Stormwater discharge associated with large construction activity" means the discharge of stormwater from large construction activities.

"Stormwater discharge associated with small construction activity" means the discharge of stormwater from small construction activities.

"Stormwater extended detention basin" or "extended detention basin" means a stormwater management facility that temporarily impounds runoff and discharges it through a hydraulic outlet structure over a specified period of time to a downstream conveyance system for the purpose of water quality enhancement or stream channel erosion control. While a certain amount of outflow may also occur via infiltration through the surrounding soil, such amounts are negligible when compared to the outlet structure discharge rates and, therefore, are not considered in the facility's design. Since an extended detention basin impounds runoff only temporarily, it is normally dry during nonrainfall periods.

"Stormwater extended detention basin-enhanced" or "extended detention basin-enhanced" means an extended detention basin modified to increase pollutant removal by providing a shallow marsh in the lower stage of the basin.

"Stormwater management facility" means a device that controls stormwater runoff and changes the characteristics of that runoff including, but not limited to, the quantity and quality, the period of release or the velocity of flow.

"Stormwater management plan" means a document document(s) containing material for describing how existing runoff characteristics will be maintained by a land-disturbing activity and methods for complying with the requirements of the local program or this chapter.

"Stormwater Management Program" means a program established by a locality that is consistent with the requirements of the Virginia Stormwater Management Act, this chapter and associated guidance documents.

"Stormwater management standards" means the minimum criteria for stormwater management programs and land-disturbing activities as set out in Part II (4VAC50-60-40 et seq.) of this chapter.

"Stormwater Pollution Prevention Plan" (SWPPP) or "plan" means a document that is prepared in accordance with good engineering practices and that identifies potential sources of pollution that may reasonably be expected to affect the quality of stormwater discharges from the construction site or its associated land-disturbing activities. In addition the document shall describe and ensure the implementation of best management practices, and shall include, but not be limited to the inclusion of, or the incorporation by reference of, an erosion and sediment control plan, a post-construction stormwater management plan, a spill prevention control and countermeasure (SPCC) plan, and other practices that will be used to reduce pollutants in stormwater discharges from land-disturbing activities and to assure compliance with the terms and conditions of this chapter. All plans incorporated by reference into the SWPPP shall be enforceable under the permit issued.

"Stormwater retention basin" or "retention basin" means a stormwater management facility that includes a permanent impoundment, or normal pool of water, for the purpose of enhancing water quality and, therefore, is normally wet, even during nonrainfall periods. Storm runoff inflows may be temporarily stored above this permanent impoundment for the purpose of reducing flooding, or stream channel erosion.

"Stormwater retention basin I" or "retention basin I" means a retention basin with the volume of the permanent pool equal to three times the water quality volume.

"Stormwater retention basin II" or "retention basin II" means a retention basin with the volume of the permanent pool equal to four times the water quality volume.

"Stormwater retention basin III" or "retention basin III" means a retention basin with the volume of the permanent pool equal to four times the water quality volume with the addition of an aquatic bench.

"Subdivision" means the same as defined in § 15.2-2201 of the Code of Virginia.

"Surface waters" means:

1. All waters that are currently used, were used in the past, or may be susceptible to use in interstate or foreign commerce, including all waters that are subject to the ebb and flow of the tide;

2. All interstate waters, including interstate wetlands;

3. All other waters such as intrastate lakes, rivers, streams (including intermittent streams), mudflats, sandflats, wetlands, sloughs, prairie potholes, wet meadows, playa lakes, or natural ponds the use, degradation, or destruction of which would affect or could affect interstate or foreign commerce including any such waters:

a. That are or could be used by interstate or foreign travelers for recreational or other purposes;

b. From which fish or shellfish are or could be taken and sold in interstate or foreign commerce; or

c. That are used or could be used for industrial purposes by industries in interstate commerce.

4. All impoundments of waters otherwise defined as surface waters under this definition;

5. Tributaries of waters identified in subdivisions 1 through 4 of this definition;

6. The territorial sea; and

7. Wetlands adjacent to waters (other than waters that are themselves wetlands) identified in subdivisions 1 through 6 of this definition.

Waste treatment systems, including treatment ponds or lagoons designed to meet the requirements of the CWA and the law, are not surface waters. Surface waters do not include prior converted cropland. Notwithstanding the determination of an area's status as prior converted cropland by any other agency, for the purposes of the Clean Water Act, the final authority regarding the Clean Water Act jurisdiction remains with the EPA.

"Total dissolved solids" means the total dissolved (filterable) solids as determined by use of the method specified in 40 CFR Part 136 (2000).

"Total maximum daily load" or "TMDL" means the sum of the individual wasteload allocations for point sources, load allocations (LAs) for nonpoint sources, natural background loading and a margin of safety. TMDLs can be expressed in terms of either mass per time, toxicity, or other appropriate measure. The TMDL process provides for point versus nonpoint source trade-offs.

"Toxic pollutant" means any pollutant listed as toxic under § 307(a)(1) of the CWA or, in the case of sludge use or disposal practices, any pollutant identified in regulations implementing § 405(d) of the CWA.

"Unstable" means, in the context of channels, a channel that is not stable.

"Upset" means an exceptional incident in which there is unintentional and temporary noncompliance with technology based permit effluent limitations because of factors beyond the reasonable control of the operator. An upset does not include noncompliance to the extent caused by operational error, improperly designed treatment facilities, inadequate treatment facilities, lack of preventive maintenance, or careless or improper operation.

"Variance" means any mechanism or provision under § 301 or § 316 of the CWA or under 40 CFR Part 125 (2000), or in the applicable effluent limitations guidelines that allows modification to or waiver of the generally applicable effluent limitation requirements or time deadlines of the CWA. This includes provisions that allow the establishment of alternative limitations based on fundamentally different factors or on § 301(c), § 301(g), § 301(h), § 301(i), or § 316(a) of the CWA.

"Vegetated filter strip" means a densely vegetated section of land engineered to accept runoff as overland sheet flow from upstream development. It shall adopt any natural vegetated form, from grassy meadow to small forest. The vegetative cover facilitates pollutant removal through filtration, sediment deposition, infiltration and absorption, and is dedicated for that purpose.

"Virginia Pollutant Discharge Elimination System (VPDES) permit" or "VPDES permit" means a document issued by the State Water Control Board pursuant to the State Water Control Law authorizing, under prescribed conditions, the potential or actual discharge of pollutants from a point source to surface waters and the use or disposal of sewage sludge.

"Virginia Stormwater Management Act" or "Act" means Article 1.1 (§ 10.1-603.1 et seq.) of Chapter 6 of Title 10.1 of the Code of Virginia.

"Virginia Stormwater Management Handbook" means a collection of pertinent information that provides general guidance for compliance with the Act and associated regulations and is developed by the department with advice from a stakeholder advisory committee.

"Virginia Stormwater Management Program (VSMP)" or "VSMP" means the Virginia program for issuing, modifying, revoking and reissuing, terminating, monitoring and enforcing permits, and imposing and enforcing requirements pursuant to the federal Clean Water Act CWA, the Virginia Stormwater Management Act, this chapter, and associated guidance documents.

"Virginia Stormwater Management Program (VSMP) permit" or "VSMP permit" means a document issued by the permit-issuing authority pursuant to the Virginia Stormwater Management Act and this chapter authorizing, under prescribed conditions, the potential or actual discharge of pollutants from a point source to surface waters. Under the approved state program, a VSMP permit is equivalent to a NPDES permit.

"VSMP application" or "application" means the standard form or forms, including any additions, revisions or modifications to the forms, approved by the administrator and the board for applying for a VSMP permit.

"Wasteload allocation" or "wasteload" or "WLA" means the portion of a receiving surface water's loading or assimilative capacity allocated to one of its existing or future point sources of pollution. WLAs are a type of water quality-based effluent limitation.

"Water quality standards" or "WQS" means provisions of state or federal law that consist of a designated use or uses for the waters of the Commonwealth and water quality criteria for such waters based on such uses. Water quality standards are to protect the public health or welfare, enhance the quality of water, and serve the purposes of the State Water Control Law (§ 62.1-44.2 et seq. of the Code of Virginia), the Virginia Stormwater Management Act (§ 10.1-603.1 et seq. of the Code of Virginia), and the federal Clean Water Act CWA (33 USC § 1251 et seq.).

"Water quality volume" means the volume equal to the first 1/2 inch of runoff multiplied by the impervious surface of the land development project.

"Watershed" means a defined land area drained by a river or stream, karst system, or system of connecting rivers or streams such that all surface water within the area flows through a single outlet. In karst areas, the karst feature to which the water drains may be considered the single outlet for the watershed.

"Wetlands" means those areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas.

"Whole effluent toxicity" means the aggregate toxic effect of an effluent measured directly by a toxicity test.

4VAC50-60-20. Purposes.

The purposes of this chapter are to provide a framework for the administration, implementation and enforcement of the Virginia Stormwater Management Act (Act) and to delineate the procedures and requirements to be followed in connection with VSMP permits issued by the board or its designee pursuant to the Clean Water Act (CWA) and the Virginia Stormwater Management Act, while at the same time providing flexibility for innovative solutions to stormwater management issues. The chapter also establishes the board's procedures for the authorization of a qualifying local program, board and department oversight authorities for an authorized qualifying local program, the board's procedures for utilization by the department in administering a local program in localities where no qualifying local program is authorized, and the components of a stormwater management program including but not limited to stormwater management standards.

4VAC50-60-30. Applicability.

This chapter is applicable to:

1. Every private, local, state, or federal entity that establishes a stormwater management program or a MS4 program;

2. The department in its oversight of locally administered programs or in its administration of a local program;

2. 3. Every state agency project regulated under the Act and this chapter; and

3. 4. Every land-disturbing activity regulated under § 10.1-603.8 of the Code of Virginia unless otherwise exempted in § 10.1-603.8 B.

Part II
Stormwater Management Program Technical Criteria

4VAC50-60-40. Applicability Authority and applicability.

This part specifies technical criteria for every stormwater management program and land-disturbing activity.

Pursuant to the Virginia Stormwater Management Act (§ 10.1-603.2 et seq. of the Code of Virginia), the board is required to take actions ensuring the general health, safety, and welfare of the citizens of the Commonwealth as well as protecting the quality and quantity of state waters from the potential harm of unmanaged stormwater. In addition to other authority granted to the board under the Stormwater Management Act, the board is authorized pursuant to §§ 10.1-603.2:1 and 10.1-603.4 to adopt regulations that specify minimum technical criteria for stormwater management programs in Virginia, to establish statewide standards for stormwater management from land-disturbing activities, and to protect properties, the quality and quantity of state waters, the physical integrity of stream channels, and other natural resources.

In accordance with the board's authority, this part establishes the minimum technical criteria and stormwater management standards that shall be employed by a state agency in accordance with an implementation schedule set by the board, or by a qualifying local program or department-administered local stormwater management program that has been approved by the board, to protect the quality and quantity of state waters from the potential harm of unmanaged stormwater runoff resulting from land-disturbing activities.

For those localities required to adopt a local stormwater management program pursuant to § 10.1-603.3 of the Code of Virginia, until a local program is approved by the board, the technical criteria required shall be that found at 4VAC50-60-1180 through 4VAC50-60-1190.

4VAC50-60-50. General. (Repealed.)

A. Determination of flooding and channel erosion impacts to receiving streams due to land-disturbing activities shall be measured at each point of discharge from the land disturbance and such determination shall include any runoff from the balance of the watershed which also contributes to that point of discharge.

B. The specified design storms shall be defined as either a 24-hour storm using the rainfall distribution recommended by the U.S. Department of Agriculture's Natural Resources Conservation Service (NRCS) when using NRCS methods or as the storm of critical duration that produces the greatest required storage volume at the site when using a design method such as the Modified Rational Method.

C. For purposes of computing runoff, all pervious lands in the site shall be assumed prior to development to be in good condition (if the lands are pastures, lawns, or parks), with good cover (if the lands are woods), or with conservation treatment (if the lands are cultivated); regardless of conditions existing at the time of computation.

D. Construction of stormwater management facilities or modifications to channels shall comply with all applicable laws and regulations. Evidence of approval of all necessary permits shall be presented.

E. Impounding structures that are not covered by the Impounding Structure Regulations (4VAC50-20) shall be engineered for structural integrity during the 100-year storm event.

F. Pre-development and post-development runoff rates shall be verified by calculations that are consistent with good engineering practices.

G. Outflows from a stormwater management facility or stormwater conveyance system, shall be discharged to an adequate channel.

H. Proposed residential, commercial, or industrial subdivisions shall apply these stormwater management criteria to the land disturbance as a whole. Individual lots in new subdivisions shall not be considered separate land-disturbing activities, but rather the entire subdivision shall be considered a single land development project. Hydrologic parameters shall reflect the ultimate land disturbance and shall be used in all engineering calculations.

I. All stormwater management facilities shall have an inspection and maintenance plan that identifies the owner and the responsible party for carrying out the inspection and maintenance plan.

J. Construction of stormwater management impoundment structures within a Federal Emergency Management Agency (FEMA) designated 100-year floodplain shall be avoided to the extent possible. When this is unavoidable, all stormwater management facility construction shall be in compliance with all applicable regulations under the National Flood Insurance Program, 44 CFR Part 59.

K. Natural channel characteristics shall be preserved to the maximum extent practicable.

L. Land-disturbing activities shall comply with the Virginia Erosion and Sediment Control Law (§ 10.1-560 et seq. of the Code of Virginia) and attendant regulations.

M. Flood control and stormwater management facilities that drain or treat water from multiple development projects or from a significant portion of a watershed may be allowed in Resource Protection Areas defined in the Chesapeake Bay Preservation Act, provided that (i) the local government has conclusively established that the location of the facility within the Resource Protection Area is the optimum location; (ii) the size of the facility is the minimum necessary to provide necessary flood control, stormwater treatment, or both; and, (iii) the facility must be consistent with a stormwater management program that has been approved by the board.

4VAC50-60-53. General requirements.

The physical, chemical, biological, and hydrologic characteristics and the water quality and quantity of the receiving state waters shall be maintained, protected, or improved in accordance with the requirements of this part. Objectives include, but are not limited to, supporting state designated uses and water quality standards. All control measures used shall be employed in a manner that minimizes impacts on receiving state waters.

4VAC50-60-56. Applicability of other laws and regulations.

Nothing in this chapter shall be construed as limiting the applicability of other laws and regulations, including, but not limited to, the CWA, Virginia Stormwater Management Act, Virginia Erosion and Sediment Control Law, and the Chesapeake Bay Preservation Act, except as provided in § 10.1-603.3 I of the Code of Virginia and all applicable regulations adopted in accordance with those laws, or the rights of other federal agencies, state agencies, or local governments to impose more stringent technical criteria or other requirements as allowed by law.

4VAC50-60-60. Water quality. (Repealed.)

A. Compliance with the water quality criteria may be achieved by applying the performance-based criteria or the technology-based criteria to either the site or a planning area.

B. Performance-based criteria. For land-disturbing activities, the calculated post-development nonpoint source pollutant runoff load shall be compared to the calculated pre-development load based upon the average land cover condition or the existing site condition. A BMP shall be located, designed, and maintained to achieve the target pollutant removal efficiencies specified in Table 1 to effectively reduce the pollutant load to the required level based upon the following four applicable land development situations for which the performance criteria apply:

1. Situation 1 consists of land-disturbing activities where the existing percent impervious cover is less than or equal to the average land cover condition and the proposed improvements will create a total percent impervious cover which is less than the average land cover condition.

Requirement: No reduction in the after disturbance pollutant discharge is required.

2. Situation 2 consists of land-disturbing activities where the existing percent impervious cover is less than or equal to the average land cover condition and the proposed improvements will create a total percent impervious cover which is greater than the average land cover condition.

Requirement: The pollutant discharge after disturbance shall not exceed the existing pollutant discharge based on the average land cover condition.

3. Situation 3 consists of land disturbing activities where the existing percent impervious cover is greater than the average land cover condition.

Requirement: The pollutant discharge after disturbance shall not exceed (i) the pollutant discharge based on existing conditions less 10% or (ii) the pollutant discharge based on the average land cover condition, whichever is greater.

4. Situation 4 consists of land disturbing activities where the existing percent impervious cover is served by an existing stormwater management BMP that addresses water quality.

Requirement: The pollutant discharge after disturbance shall not exceed the existing pollutant discharge based on the existing percent impervious cover while served by the existing BMP. The existing BMP shall be shown to have been designed and constructed in accordance with proper design standards and specifications, and to be in proper functioning condition.

C. Technology-based criteria. For land-disturbing activities, the post-developed stormwater runoff from the impervious cover shall be treated by an appropriate BMP as required by the post-developed condition percent impervious cover as specified in Table 1. The selected BMP shall be located, designed, and maintained to perform at the target pollutant removal efficiency specified in Table 1. Design standards and specifications for the BMPs in Table 1 that meet the required target pollutant removal efficiency will be available at the department.

Table 1*

Water Quality BMP*	Target Phosphorus Removal Efficiency	Percent Impervious Cover
Vegetated filter strip Grassed Swale	10% 15%	16-21%
Constructed wetlands Extended detention (2 x WQ Vol) Retention basin I (3 x WQ Vol)	20% 35% 40%	22-37%
Bioretention basin Bioretention filter Extended detention-enhanced Retention basin II (4 x WQ Vol) Infiltration (1 x WQ Vol)	50% 50% 50% 50% 50%	38-66%
Sand filter Infiltration (2 x WQ Vol) Retention basin III (4 x WQ Vol with aquatic bench)	65% 65% 65%	67-100%

*Innovative or alternate BMPs not included in this table may be allowed at the discretion of the local program administrator or the department. Innovative or alternate BMPs not included in this table which target appropriate nonpoint source pollution other than phosphorous may be allowed at the discretion of the local program administrator or the department.

4VAC50-60-63. Water quality criteria requirements.

In order to protect the quality of state waters and to control nonpoint source pollution, the following minimum technical criteria and statewide standards for stormwater management shall be applied to the site of a land-disturbing activity. The local program shall have discretion to allow for application of the criteria to each drainage area of the site. However, where a site drains to more than one HUC, the pollutant load reduction requirements shall be applied independently within each HUC unless reductions are achieved in accordance with a comprehensive watershed stormwater management plan in accordance with 4VAC50-60-96.

1. New development. The total phosphorus load of new development projects shall not exceed 0.28 pounds per acre per year, as calculated pursuant to 4VAC50-60-65.

2. Development on prior developed lands. The total phosphorus load of projects occurring on prior developed lands shall be reduced to an amount at least 20% below the predevelopment total phosphorus load. However, the total phosphorus load shall not be required to be reduced to below 0.28 pounds per acre per year unless a more stringent standard has been established by a qualifying local program.

3. Compliance with 4VAC50-60-65 shall constitute compliance with subdivisions 1 and 2 of this section.

4. TMDL. In addition to the above requirements, if a specific WLA for a pollutant has been established in a TMDL and is assigned to stormwater discharges from a construction activity, necessary control measures must be implemented by the operator to meet the WLA in accordance with the requirements established in the General Permit for Discharges of Stormwater from Construction Activities or an individual permit, which address both construction and postconstruction discharges.

4VAC50-60-65. Water quality compliance.

A. Compliance with the water quality criteria set out in subdivisions 1 and 2 of 4VAC50-60-63 shall be determined by utilizing the Virginia Runoff Reduction Method or another methodology that is demonstrated by the qualifying local program to achieve equivalent or more stringent results and is approved by the board.

B. The BMPs listed in Table 1 or the BMPs available on the Virginia Stormwater BMP Clearinghouse website shall be utilized as necessary to effectively reduce the phosphorus load in accordance with the Virginia Runoff Reduction Method. Design specifications for the BMPs listed in Table 1 can be found at http://www.vwrrc.vt.edu/swc.

TABLE 1 BMP Pollutant Removal Efficiencies
Practice	Removal of Total Phosphorus by Runoff Volume Reduction (RR, as %) (based upon 1 inch of rainfall --90% storm)	Removal of Total Phosphorus by Treatment -- Pollutant Concentration Reduction (PR, as %)	Total Removal of Total Phosphorus (TR, as %)
Green Roof 1	45	0	45
Green Roof 2	60	0	60
Rooftop Disconnection 1	25	0	25
Rooftop Disconnection 2	50	0	50
Rain Tanks/ Cisterns 1	actual volume x .75	0	actual volume x .75
Soil Amendments 1	50	0	50
Soil Amendments 2	75	0	75
Permeable Pavement 1	45	25	59
Permeable Pavement 2	75	25	81
Grass Channel 1	10	15	23
Grass Channel 2	20	15	32
Bioretention 1	40	25	55
Bioretention 2	80	50	90
Infiltration 1	50	25	63
Infiltration 2	90	25	93
Dry Swale 1	40	20	52
Dry Swale 2	60	40	76
Wet Swale 1	0	20	20
Wet Swale 2	0	40	40
Sheet Flow to Conserved Open Space 1	0	50	50
Sheet Flow to Conserved Open Space 2	0	75	75
Extended Detention Pond 1	0	15	15
Extended Detention Pond 2	15	15	28
Filtering Practice 1	0	60	60
Filtering Practice 2	0	65	65
Constructed Wetland 1	0	50	50
Constructed Wetland 2	0	75	75
Wet Pond 1	0	50	50
Wet Pond 2	0	75	75

C. BMPs differing from those listed in Table 1 shall be reviewed and approved by the director in accordance with procedures established by the BMP Clearinghouse Committee and approved by the board.

D. A qualifying local program may establish use limitations on specific BMPs following the submission of the proposed use limitation and written justification to the department.

E. Where the land-disturbing activity only occurs on a portion of the site, the local program may review the stormwater management plan based upon the portion of the site that is proposed to be developed, provided that the local program has established guidance for such a review. Such portion shall be deemed to include any area left undeveloped pursuant to any local requirement or proffer accepted by a locality. Any such guidance shall be provided to the department.

F. If a comprehensive watershed stormwater management plan has been adopted pursuant to 4VAC50-60-96 for the watershed within which a project is located, then the qualifying local program may allow offsite controls in accordance with the plan to achieve the postdevelopment pollutant load water quality technical criteria set out in subdivisions 1 and 2 of 4VAC50-60-63. Such offsite controls shall achieve the required pollutant reductions either completely offsite in accordance with the plan or in a combination of onsite and offsite controls.

G. Where no plan exists pursuant to subsection F of this section, offsite controls may be used to meet the postdevelopment pollutant load water quality technical criteria set out in subdivisions 1 and 2 of 4VAC50-60-63 provided:

1. The local program allows for offsite controls;

2. The applicant demonstrates to the satisfaction of the local program that offsite reductions equal to or greater than those that would otherwise be required for the site are achieved;

3. The applicant demonstrates to the satisfaction of the local program that the development's runoff and the runoff from any offsite treatment area shall be controlled in accordance with 4VAC50-60-66;

4. Offsite controls must be located within the same HUC or the adjacent downstream HUC to the land-disturbing site; and

5. The applicant demonstrates to the satisfaction of the local program that the right to utilize the offsite control area and any necessary easements has been obtained and maintenance agreements for the stormwater management facilities have been established pursuant to 4VAC50-60-124.

H. Alternatively, the local program may waive the requirements of subdivisions 1 and 2 of 4VAC50-60-63 through the granting of an exception pursuant to 4VAC50-60-122.

4VAC50-60-66. Water quantity.

A. Channel protection and flood protection shall be addressed in accordance with the minimum standards set out in this section, which are established pursuant to the requirements of subdivision 7 of § 10.1-603.4 of the Code of Virginia.

B. Channel protection. Concentrated stormwater flow from the site and offsite contributing areas shall be released into a stormwater conveyance system and shall meet one of the following criteria as demonstrated by use of accepted hydrologic and hydraulic methodologies:

1. Concentrated stormwater flow to manmade stormwater conveyance systems. The point of discharge releases stormwater into a manmade stormwater conveyance system that, following the land-disturbing activity, conveys the postdevelopment peak flow rate from the two-year 24-hour storm without causing erosion of the system.

2. Concentrated stormwater flow to restored stormwater conveyance systems. The point of discharge releases stormwater into a stormwater conveyance system that (i) has been restored and is functioning as designed or (ii) will be restored. The applicant must demonstrate that the runoff following the land-disturbing activity, in combination with other existing stormwater runoff, will not exceed the design of the restored stormwater conveyance system nor result in instability of the system.

3. Concentrated stormwater flow to stable natural stormwater conveyance systems. The point of discharge releases stormwater into a natural stormwater conveyance system that is stable and, following the land-disturbing activity, (i) will not become unstable as a result of the discharge from the one-year 24-hour storm, and (ii) provides a peak flow rate from the one-year 24-hour storm calculated as follows or in accordance with another methodology that is demonstrated by the local program to achieve equivalent results and is approved by the board:

Q_Developed* RV_Developed ≤ Q_{Pre-Developed} * RV_{Pre-Developed}, where

Q_Developed = The allowable peak flow rate of runoff from the developed site.

Q_{Pre-Developed} = The peak flow rate of runoff from the site in the predeveloped condition.

RV_{Pre-Developed} = The volume of runoff from the site in the predeveloped condition.

RV_Developed = The volume of runoff from the developed site.

4. Concentrated stormwater flow to unstable natural stormwater conveyance systems. Where the point of discharge releases stormwater into a natural stormwater conveyance system that is unstable, stormwater runoff following a land-disturbing activity shall be released into a channel at or below a peak flow rate (Q_Developed) based on the one-year 24-hour storm, calculated as follows or in accordance with another methodology that is demonstrated by the local program to achieve equivalent or more stringent results and is approved by the board:

Q_Developed* RV_Developed ≤ Q_Forested * RV_Forested, where

Q_Developed = The allowable peak flow rate from the developed site.

Q_Forested = The peak flow rate from the site in a forested condition.

RV_Forested = The volume of runoff from the site in a forested condition.

RV_Developed = The volume of runoff from the developed site.

C. Flood protection. Concentrated stormwater flow shall be released into a stormwater conveyance system and shall meet one of the following criteria as demonstrated by use of accepted hydrologic and hydraulic methodologies:

1. Concentrated stormwater flow to manmade stormwater conveyance systems. The point of discharge releases stormwater into a manmade stormwater conveyance system that, following the land-disturbing activity, confines the postdevelopment peak flow rate from the 10-year 24-hour storm within the manmade stormwater conveyance system.

2. Concentrated stormwater flow to restored stormwater conveyance systems. The point of discharge releases stormwater into a stormwater conveyance system that (i) has been restored and is functioning as designed or (ii) will be restored. The applicant must demonstrate that the peak flow rate from the 10-year 24-hour storm following the land-disturbing activity will be confined within the system.

3. Concentrated stormwater flow to natural stormwater conveyance systems. The point of discharge releases stormwater into a natural stormwater conveyance system that currently does not flood during the 10-year 24-hour storm and, following the land-disturbing activity, confines the postdevelopment peak flow rate from the 10-year 24-hour storm within the system.

4. Concentrated stormwater flow to natural stormwater conveyance systems where localized flooding exists during the 10-year 24-hour storm. The point of discharge releases a postdevelopment peak flow rate for the 10-year 24-hour storm that shall not exceed the predevelopment peak flow rate from the 10-year 24-hour storm based on forested conditions.

5. A local program may adopt alternate flood protection design criteria that (i) achieve equivalent or more stringent results, (ii) are based upon geographic, land use, topographic, geologic, or other downstream conveyance factors, and (iii) are approved by the board.

D. One percent rule. If either of the following criteria are met, subsections A and B of this section do not apply:

1. Based on area. Prior to any land disturbance, the site's contributing drainage area to a point of discharge from the site is less than or equal to 1.0% of the total watershed area draining to that point of discharge; or

2. Based on peak flow rate. Based on the postdevelopment land cover conditions prior to the implementation of any stormwater quantity control measures, the development of the site results in an increase in the peak flow rate from the one-year 24-hour storm that is less than 1.0% of the existing peak flow rate from the one-year 24-hour storm generated by the total watershed area draining to that point of discharge.

E. Increased volumes of sheet flow resulting from pervious or disconnected impervious areas, or from physical spreading of concentrated flow through level spreaders, must be identified and evaluated for potential impacts on down gradient properties or resources. Increased volumes of sheet flow that will cause or contribute to erosion, sedimentation, or flooding of down gradient properties or resources shall be diverted to a detention facility or a stormwater conveyance system that conveys the runoff without causing down gradient erosion, sedimentation, or flooding. If all runoff from the site is sheet flow and the conditions of this subsection are met, no further water quantity controls are required.

F. For purposes of computing predevelopment runoff from prior developed sites, all pervious lands on the site shall be assumed to be in good hydrologic condition in accordance with the U.S. Department of Agriculture's Natural Resources Conservation Service (NRCS) standards, regardless of conditions existing at the time of computation. Predevelopment runoff calculations utilizing other hydrologic conditions may be utilized provided that it is demonstrated to and approved by the local program that actual site conditions warrant such considerations.

G. Predevelopment runoff characteristics and site hydrology shall be verified by site inspections, topographic surveys, available soil mapping or studies, and calculations consistent with good engineering practices in accordance with guidance provided in the Virginia Stormwater Management Handbook and by the qualifying local program.

H. Except where the compliance options under subdivisions B 4 and C 4 of this section are utilized, flooding and channel erosion impacts to stormwater conveyance systems shall be analyzed for each point of discharge in accordance with channel analysis guidance provided in Technical Bulletin # 1, Stream Channel Erosion Control, or in accordance with more stringent channel analysis guidance established by the qualifying local program and provided to the department. Such analysis shall include estimates of runoff from the developed site and the entire upstream watershed that contributes to that point of discharge. Good engineering practices and calculations in accordance with department guidance shall be used to evaluate postdevelopment runoff characteristics and site hydrology, and flooding and channel erosion impacts.

If the downstream owner or owners refuse to give permission to access the property for the collection of data, evidence of this refusal shall be given and arrangements made satisfactory to the local program to provide an alternative method for the collection of data to complete the analysis, such as through the use of photos, aerial surveys, "as built" plans, topographic maps, soils maps, and any other relevant information.

4VAC50-60-70. Stream channel erosion. (Repealed.)

A. Properties and receiving waterways downstream of any land-disturbing activity shall be protected from erosion and damage due to changes in runoff rate of flow and hydrologic characteristics, including but not limited to, changes in volume, velocity, frequency, duration, and peak flow rate of stormwater runoff in accordance with the minimum design standards set out in this section.

B. The permit-issuing authority shall require compliance with subdivision 19 of 4VAC50-30-40 of the Erosion and Sediment Control Regulations, promulgated pursuant to Article 4 (§ 10.1-560 et seq.) of Chapter 5 of Title 10.1 of the Code of Virginia.

C. The permit-issuing authority may determine that some watersheds or receiving stream systems require enhanced criteria in order to address the increased frequency of bankfull flow conditions (top of bank) brought on by land-disturbing activities. Therefore, in lieu of the reduction of the two-year post-developed peak rate of runoff as required in subsection B of this section, the land development project being considered shall provide 24-hour extended detention of the runoff generated by the one-year, 24-hour duration storm.

D. In addition to subsections B and C of this section permit-issuing authorities, by local ordinance may, or the board by state regulation may, adopt more stringent channel analysis criteria or design standards to ensure that the natural level of channel erosion, to the maximum extent practicable, will not increase due to the land-disturbing activities. These criteria may include, but are not limited to, the following:

1. Criteria and procedures for channel analysis and classification.

2. Procedures for channel data collection.

3. Criteria and procedures for the determination of the magnitude and frequency of natural sediment transport loads.

4. Criteria for the selection of proposed natural or man-made channel linings.

4VAC50-60-72. Design storms and hydrologic methods.

A. Unless otherwise specified, the prescribed design storms are the one-year, two-year, and 10-year 24-hour storms using the site-specific rainfall precipitation frequency data recommended by the U.S. National Oceanic and Atmospheric Administration (NOAA) Atlas 14. Partial duration time series shall be used for the precipitation data.

B. All hydrologic analyses shall be based on the existing watershed characteristics and the ultimate development condition of the subject project.

C. The U.S. Department of Agriculture's Natural Resources Conservation Service (NRCS) synthetic 24-hour rainfall distribution and models, including, but not limited to TR-55 and TR-20; hydrologic and hydraulic methods developed by the U.S. Army Corps of Engineers; or other standard hydrologic and hydraulic methods, shall be used to conduct the analyses described in this part.

D. The local program may allow for the use of the Rational Method for evaluating peak discharges or the Modified Rational Method for evaluating volumetric flows to stormwater conveyances with drainage areas of 200 acres or less.

4VAC50-60-74. Stormwater harvesting.

In accordance with § 10.1-603.4 of the Code of Virginia, stormwater harvesting is encouraged for the purposes of landscape irrigation systems, fire protection systems, flushing water closets and urinals, and other water handling systems to the extent such systems are consistent with federal, state, and local regulatory authorities.

4VAC50-60-76. Linear development projects.

Unless exempt pursuant to § 10.1-603.8 B of the Code of Virginia, linear development projects shall control postdevelopment stormwater runoff in accordance with a site-specific stormwater management plan or a comprehensive watershed stormwater management plan developed in accordance with these regulations.

4VAC50-60-80. Flooding. (Repealed.)

A. Downstream properties and waterways shall be protected from damages from localized flooding due to changes in runoff rate of flow and hydrologic characteristics, including but not limited to, changes in volume, velocity, frequency, duration, and peak flow rate of stormwater runoff in accordance with the minimum design standards set out in this section.

B. The 10-year post-developed peak rate of runoff from the development site shall not exceed the 10-year pre-developed peak rate of runoff.

C. In lieu of subsection B of this section, localities may, by ordinance, adopt alternate design criteria based upon geographic, land use, topographic, geologic factors or other downstream conveyance factors as appropriate.

D. Linear development projects shall not be required to control post-developed stormwater runoff for flooding, except in accordance with a watershed or regional stormwater management plan.

4VAC50-60-85. Stormwater management impoundment structures or facilities.

A. Construction of stormwater management impoundment structures or facilities within tidal or nontidal wetlands and perennial streams is not recommended.

B. Construction of stormwater management impoundment structures or facilities within a Federal Emergency Management Agency (FEMA) designated 100-year floodplain is not recommended.

C. Stormwater management wet ponds and extended detention ponds that are not covered by the Impounding Structure Regulations (4VAC50-20) shall be engineered for structural integrity and spillway design for the 100-year storm event.

D. Construction of stormwater management impoundment structures or facilities may occur in karst areas only after a geological study of the area has been conducted to determine the presence or absence of karst features that may be impacted by stormwater runoff and BMP placement.

E. Discharge of stormwater runoff to a karst feature shall meet the water quality criteria set out in 4VAC50-60-63 and the water quantity criteria set out in 4VAC50-60-66. Permanent stormwater management impoundment structures or facilities shall only be constructed in karst features after completion of a geotechnical investigation that identifies any necessary modifications to the BMP to ensure its structural integrity and maintain its water quality and quantity efficiencies. The person responsible for the land-disturbing activity is encouraged to screen for known existence of heritage resources in the karst features. Any Class V Underground Injection Control Well registration statements for stormwater discharges to improved sinkholes shall be included in the SWPPP.

4VAC50-60-90. Regional (watershed-wide) stormwater management plans. (Repealed.)

This section enables localities to develop regional stormwater management plans. State agencies intending to develop large tracts of land such as campuses or prison compounds are encouraged to develop regional plans where practical.

The objective of a regional stormwater management plan is to address the stormwater management concerns in a given watershed with greater economy and efficiency by installing regional stormwater management facilities versus individual, site-specific facilities. The result will be fewer stormwater management facilities to design, build and maintain in the affected watershed. It is also anticipated that regional stormwater management facilities will not only help mitigate the impacts of new development, but may also provide for the remediation of erosion, flooding or water quality problems caused by existing development within the given watershed.

If developed, a regional plan shall, at a minimum, address the following:

1. The specific stormwater management issues within the targeted watersheds.

2. The technical criteria in 4VAC50-60-40 through 4VAC50-60-80 as needed based on subdivision 1 of this section.

3. The implications of any local comprehensive plans, zoning requirements, local ordinances pursuant to the Chesapeake Bay Preservation Area Designation and Management Regulations adopted pursuant to the Chesapeake Bay Preservation Act, and other planning documents.

4. Opportunities for financing a watershed plan through cost sharing with neighboring agencies or localities, implementation of regional stormwater utility fees, etc.

5. Maintenance of the selected stormwater management facilities.

6. Future expansion of the selected stormwater management facilities in the event that development exceeds the anticipated level.

4VAC50-60-93. Stormwater management plan development.

A. A stormwater management plan for a land-disturbing activity shall apply these stormwater management technical criteria to the entire land-disturbing activity.

B. Individual lots or planned phases of developments shall not be considered separate land-disturbing activities, but rather the entire development shall be considered a single land-disturbing activity.

C. The stormwater management plan shall consider all sources of surface runoff and all sources of subsurface and groundwater flows converted to surface runoff.

4VAC50-60-96. Comprehensive watershed stormwater management plans.

A. Local programs may develop comprehensive watershed stormwater management plans to be approved by the department that meet the water quality objectives, quantity objectives, or both of this chapter:

1. Such plans shall ensure that offsite reductions equal to or greater than those that would be required on each contributing land-disturbing site are achieved within the same HUC or within another locally designated watershed. Pertaining to water quantity objectives, the plan may provide for implementation of a combination of channel improvement, stormwater detention, or other measures that are satisfactory to the local program to prevent downstream erosion and flooding.

2. If the land use assumptions upon which the plan was based change or if any other amendments are deemed necessary by the local program, the local program shall provide plan amendments to the board for review and approval.

3. During the plan's implementation, the local program shall account for nutrient reductions accredited to the BMPs specified in the plan.

4. State and federal agencies may participate in comprehensive watershed stormwater management plans where practicable and permitted by the local program.

B. If the qualifying local program allows for a pro rata fee in accordance with § 15.2-2243 of the Code of Virginia, then the reductions required for a site by this chapter may be achieved by the payment of a pro rata fee sufficient to fund improvements necessary to adequately achieve those requirements in accordance with that section of the Code of Virginia and this chapter.

Part III
Local Programs

4VAC50-60-100. Applicability. (Repealed.)

This part specifies technical criteria, minimum ordinance requirements, and administrative procedures for all localities operating local stormwater management programs.

Part III A
Local Programs

4VAC50-60-102. Authority and applicability.

If a locality has adopted a local stormwater management program in accordance with the Virginia Stormwater Management Act (§ 10.1-603.2 et seq. of the Code of Virginia) and the board has deemed such program adoption consistent with the Virginia Stormwater Management Act and these regulations in accordance with § 10.1-603.3 F of the Code of Virginia, the board may authorize a locality to administer a qualifying local program. Pursuant to § 10.1-603.4, the board is required to establish standards and procedures for such an authorization.

This part specifies the minimum technical criteria and the local government ordinance requirements for a local program to be considered a qualifying local program. Such criteria include but are not limited to administration, plan review, issuance of coverage under the Virginia Stormwater Management Program (VSMP) General Permit for Discharges of Stormwater from Construction Activities, inspection, and enforcement.

4VAC50-60-104. Technical criteria for qualifying local programs.

A. All qualifying local programs shall require compliance with the provisions of Part II (4VAC50-60-40 et seq.) of this chapter unless an exception is granted pursuant to 4VAC50-60-122 and shall comply with the requirements of 4VAC50-60-460 L.

B. When a locality operating a qualifying local program has adopted requirements more stringent than those imposed by this chapter in accordance with § 10.1-603.7 of the Code of Virginia or implemented a comprehensive stormwater management plan, the department shall consider such requirements in its review of state projects within that locality in accordance with Part IV (4VAC50-60-160 et seq.) of this chapter.

C. Nothing in this part shall be construed as authorizing a locality to regulate, or to require prior approval by the locality for, a state project.

4VAC50-60-106. Qualifying local program administrative requirements.

A. A qualifying local program shall provide for the following:

1. Identification of the authority authorizing coverage under the VSMP General Permit for Discharges of Stormwater from Construction Activities, the plan reviewing authority, the plan approving authority, the inspection authority, and the enforcement authority;

2. Technical criteria to be used in the qualifying local program;

3. Procedures for the submission and approval of plans;

4. Inspection and monitoring of land-disturbing activities covered by a permit for compliance;

5. Procedures or policies for long-term inspection and maintenance of stormwater management facilities; and

6. Enforcement.

B. A locality shall adopt an ordinance(s) that incorporates the components set out in subsection A of this section and consent to follow procedures provided by the department for the issuance, denial, revocation, termination, reissuance, transfer, or modifications of coverage under the VSMP General Permit for Discharges of Stormwater from Construction Activities.

C. A qualifying local program shall report to the department information related to the administration and implementation of the qualifying local program in accordance with 4VAC50-60-126.

D. A qualifying local program may require the submission of a reasonable performance bond or other financial surety and provide for the release of such sureties in accordance with the criteria set forth in § 10.1-603.8 of the Code of Virginia.

4VAC50-60-108. Qualifying local program stormwater management plan review.

A. A qualifying local program shall require stormwater management plans to be submitted for review and be approved prior to commencement of land-disturbing activities.

B. A qualifying local program shall approve or disapprove a stormwater management plan and required accompanying information according to the following:

1. Stormwater management plan review shall begin upon submission of a complete plan. A complete plan shall include the following elements:

a. The location of all points of stormwater discharge, receiving surface waters or karst features into which the stormwater discharges, and predevelopment and postdevelopment conditions for drainage areas, including final drainage patterns and changes to existing contours;

b. Contact information including the name, address, and telephone number of the property owner and the tax reference number and parcel number of the property or properties affected;

c. A narrative that includes a description of current site conditions and proposed development and final site conditions, including proposed stormwater management facilities and the mechanism, including an identification of financially responsible parties, through which the facilities will be operated and maintained during and after construction activity;

d. The location and the design of the proposed stormwater management facilities;

e. Information identifying the hydrologic characteristics and structural properties of soils utilized with the installation of stormwater management facilities;

f. Hydrologic and hydraulic computations of the predevelopment and postdevelopment runoff conditions for the required design storms;

g. Good engineering practices and calculations verifying compliance with the water quality and quantity requirements of this chapter;

h. A map or maps of the site that depicts the topography of the site and includes:

(1) All contributing drainage areas;

(2) Receiving surface waters or karst features into which stormwater will be discharged;

(3) Existing streams, ponds, culverts, ditches, wetlands, and other water bodies;

(4) Soil types, geologic formations, forest cover, and other vegetative areas;

(5) Current land use including existing structures, roads, and locations of known utilities and easements;

(6) Sufficient information on adjoining parcels to assess the impacts of stormwater from the site;

(7) The limits of clearing and grading, and the proposed drainage patterns on the site;

(8) Proposed buildings, roads, parking areas, utilities, and stormwater management facilities; and

(9) Proposed land use with tabulation of the percentage of surface area to be adapted to various uses, including but not limited to planned locations of utilities, roads, and easements.

i. 50% of the required fee in accordance with 4VAC50-60-820, and the required fee form must have been submitted.

2. Elements of the stormwater management plans shall be appropriately sealed and signed by a professional in adherence to all minimum standards and requirements pertaining to the practice of that profession in accordance with Chapter 4 (§ 54.1-400 et seq.) of Title 54.1 of the Code of Virginia and attendant regulations.

3. Completeness of a plan and required accompanying information shall be determined by the qualifying local program, and the applicant shall be notified of any determination, within 15 calendar days of receipt.

a. If within those 15 days the plan is deemed to be incomplete based on the criteria set out in this subsection, the applicant shall be notified in writing of the reasons the plan is deemed incomplete.

b. If a determination of completeness is made and communicated to the applicant within the 15 calendar days, an additional 60 calendar days from the date of the communication will be allowed for the review of the plan.

c. If a determination of completeness is not made and communicated to the applicant within the 15 calendar days, the plan shall be deemed complete as of the date of submission and a total of 60 calendar days from the date of submission will be allowed for the review of the plan.

d. The qualifying local program shall act within 45 days on any plan that has been previously disapproved and resubmitted.

4. During the review period, the plan shall be approved or disapproved and the decision communicated in writing to the person responsible for the land-disturbing activity or his designated agent. If the plan is not approved, the reasons for not approving the plan shall be provided in writing. Approval or denial shall be based on the plan's compliance with the requirements of this chapter and of the qualifying local program.

5. If a plan meeting all requirements of this chapter and of the qualifying local program is submitted and no action is taken within the time specified above, the plan shall be deemed approved.

C. Notwithstanding the requirements of subsection A of this section, if allowed by the qualifying local program, an initial stormwater management plan may be submitted for review and approval when it is accompanied by an erosion and sediment control plan, preliminary stormwater design for the current and future site work, fee form, and 50% of the fee required by 4VAC50-60-820. Such plans shall be limited to the initial clearing and grading of the site unless otherwise allowed by the qualifying local program. Approval by the qualifying local program of an initial plan does not supersede the need for the submittal and approval of a complete stormwater management plan and the updating of the SWPPP prior to the commencement of activities beyond initial clearing and grading and other activities approved by the local program. The initial plan shall include information detailed in subsection B of this section to the extent required by the qualifying local program and such other information as may be required by the qualifying local program.

D. Each approved plan may be modified in accordance with the following:

1. Modifications to an approved stormwater management plan shall be allowed only after review and written approval by the qualifying local program. The qualifying local program shall have 60 calendar days to respond in writing either approving or disapproving such requests.

2. Based on an inspection, the qualifying local program may require amendments to the approved stormwater management plan to address the noted deficiencies and notify the permittee of the required modifications.

4VAC50-60-110. Technical criteria for local programs. (Repealed.)

A. All local stormwater management programs shall comply with the general technical criteria as outlined in 4VAC50-60-50.

B. All local stormwater management programs which contain provisions for stormwater runoff quality shall comply with 4VAC50-60-60. A locality may establish criteria for selecting either the site or a planning area on which to apply the water quality criteria. A locality may opt to calculate actual watershed specific or locality wide values for the average land cover condition based upon:

1. Existing land use data at time of local Chesapeake Bay Preservation Act Program or department stormwater management program adoption, whichever was adopted first;

2. Watershed or locality size; and

3. Determination of equivalent values of impervious cover for nonurban land uses which contribute nonpoint source pollution, such as agriculture, forest, etc.

C. All local stormwater management programs which contain provisions for stream channel erosion shall comply with 4VAC50-60-70.

D. All local stormwater management programs must contain provisions for flooding and shall comply with 4VAC50-60-80.

E. All local stormwater management programs which contain provisions for watershed or regional stormwater management plans shall comply with 4VAC50-60-110.

F. A locality that has adopted more stringent requirements or implemented a regional (watershed-wide) stormwater management plan may request, in writing, that the department consider these requirements in its review of state projects within that locality.

G. Nothing in this part shall be construed as authorizing a locality to regulate, or to require prior approval by the locality for, a state project.

4VAC50-60-112. Qualifying local program authorization of coverage under the VSMP General Permit for Discharges of Stormwater from Construction Activities.

A. Coverage shall be authorized by the qualifying local program under the VSMP General Permit for Discharges of Stormwater from Construction Activities in accordance with the following:

1. The applicant must have an approved initial stormwater management plan or an approved stormwater management plan for the land-disturbing activity.

2. The applicant must have submitted proposed right-of-entry agreements or easements from the owner for purposes of inspection and maintenance and proposed maintenance agreements, including inspection schedules, in accordance with 4VAC50-60-124.

3. The applicant must have an approved registration statement for the VSMP General Permit for Discharges of Stormwater from Construction Activities.

4. The applicant must have submitted the required fee form and total fee required by 4VAC50-60-820.

5. Applicants submitting registration statements deemed to be incomplete must be notified within 15 working days of receipt by the qualifying local program that the registration statement is not complete and be notified (i) of what material needs to be submitted to complete the registration statement, and (ii) that the land-disturbing activity does not have coverage under the VSMP General Permit for Discharges of Stormwater from Construction Activities.

B. Coverage or termination of coverage shall be authorized through a standardized database or other method provided by the department. Such database shall include, at a minimum, permit number, operator name, activity name, acres disturbed, date of permit coverage, and site address and location as well as date of termination.

C. Coverage information pertaining to the VSMP General Permit for Discharges of Stormwater from Construction Activities shall be reported to the department in accordance with 4VAC50-60-126 by the qualifying local program.

D. The applicant shall be notified of authorization of permit coverage by the qualifying local program.

4VAC50-60-114. Inspections.

A. The qualifying local program or its designee shall inspect the land-disturbing activity during construction for compliance with the VSMP General Permit for Discharges of Stormwater from Construction Activities.

B. The person responsible for the development project or their designated agent shall submit to a qualifying local program a construction record drawing for permanent stormwater management facilities, appropriately sealed, and signed by a professional in accordance with all minimum standards and requirements pertaining to the practice of that profession pursuant to Chapter 4 (§ 54.1-400 et seq.) of Title 54.1 of the Code of Virginia and attendant regulations, certifying that the stormwater management facilities have been constructed in accordance with the approved plan. The qualifying local program shall have the construction record drawing and certification on file prior to the release of the portion of the performance bond or surety associated with the stormwater management facility.

C. The owners of stormwater management facilities shall be required to conduct inspections in accordance with an inspection schedule in a recorded maintenance agreement, and shall submit written inspection and maintenance reports to the qualifying local program upon request. Such reports, if consistent with a board-approved inspection program established in subsection D of this section, may be utilized by the qualifying local program if the inspection is conducted by a person who is licensed as a professional engineer, architect, certified landscape architect, or land surveyor pursuant to Article 1 (§ 54.1-400 et seq.) of Chapter 4 of Title 54.1 or who holds a certificate of competence from the board. The reports, if so utilized, must be kept on file with the qualifying local program

D. A qualifying local program shall establish an inspection program that ensures that the stormwater management facilities are being maintained as designed. Any inspection program shall be:

1. Approved by the board prior to implementation;

2. Established in writing;

3. Based on a system of priorities that takes into consideration the purpose and type of the facility, ownership and the existence of a recorded maintenance agreement and inspection schedule, the contributing drainage area, and downstream conditions;

4. Demonstrated to be an enforceable inspection program that meets the intent of the regulations and ensures that each stormwater management facility is inspected by the qualifying local program or its designee, not to include the owner, except as provided in subsection C of this section, at least every five years; and

5. Documented by inspection records.

E. Inspection reports shall be generated and kept on file in accordance with 4VAC50-60-126 for all stormwater management facilities inspected by the qualifying local program.

4VAC50-60-116. Qualifying local program enforcement.

A. A qualifying local program may incorporate the following components:

1. Informal and formal administrative enforcement procedures including:

a. Verbal warnings and inspection reports;

b. Notices of corrective action;

c. Consent special orders and civil charges in accordance with subdivision 7 of § 10.1-603.2:1 and § 10.1-603.14 D 2 of the Code of Virginia;

d. Notices to comply in accordance with § 10.1-603.11 of the Code of Virginia;

e. Special orders in accordance with subdivision 7 of § 10.1-603.2:1 of the Code of Virginia;

f. Emergency special orders in accordance with subdivision 7 of § 10.1-603.2:1 of the Code of Virginia; and

g. Public notice and comment periods pursuant to 4VAC50-60-660.

2. Civil and criminal judicial enforcement procedures including:

a. Schedule of civil penalties set out in subsection D of this section;

b. Criminal penalties in accordance with § 10.1-603.14 B and C of the Code of Virginia; and

c. Injunctions in accordance with §§ 10.1-603.12:4, 10.1-603.2:1 and 10.1-603.14 D 1 of the Code of Virginia.

B. A qualifying local program shall develop policies and procedures that outline the steps to be taken regarding enforcement actions under the Stormwater Management Act and attendant regulations and the local ordinance.

C. A qualifying local program may utilize the department's Stormwater Management Enforcement Manual as guidance in establishing policies and procedures.

D. A court may utilize as guidance the following Schedule of Civil Penalties set by the board in accordance with § 10.1-603.14 A of the Code of Virginia. The range contained within the schedule reflects the degree of harm caused by the violation, which is site-specific and may vary greatly from case to case, as may the economic benefit of noncompliance to the violator. Each day of violation of each requirement shall constitute a separate offense. Assignment of the degree of harm is a qualitative decision subject to the court's discretion. The court has the discretion to impose a maximum penalty of $32,500 per violation per day in accordance with § 10.1-603.14 A of the Code of Virginia.