Final Regulation

Title of Regulation: 9VAC25-870. Virginia Stormwater Management Program (VSMP) Regulation (amending 9VAC25-870-10, 9VAC25-870-51, 9VAC25-870-66, 9VAC25-870-103, 9VAC25-870-148; adding 9VAC25-870-52).

Statutory Authority: §§ 62.1-44.15:25 and 62.1-44.15:28 of the Code of Virginia.

Effective Date: November 14, 2018.

Agency Contact: Jaime Robb, Department of Environmental Quality, 1111 East Main Street, Suite 1400, P.O. Box 1105, Richmond, VA 23218, telephone (804) 698-4416, or email jaime.robb@deq.virginia.gov.

Summary:

Pursuant to Chapters 154 and 155 of the 2018 Acts of Assembly, the amendments authorize any rural Tidewater locality, in order for land-disturbing activities that disturb an area of 2,500 square feet or more but less than one acre to comply with the water quantity technical criteria in the Stormwater Management Act, to (i) adopt a tiered approach to manage water quantity based on the percentage of impervious cover in the watershed; and (ii) require a licensed professional retained by the applicant to submit a set of plans and supporting calculations that bear a certification and are signed and sealed by the licensed professional and accept such plans in satisfaction of the local plan review requirements.

Pursuant to Chapter 630 of the 2018 Acts of Assembly, the amendments require a Virginia Stormwater Management Program (VSMP) Authority to recommend that the Department of Environmental Quality terminate coverage under a General Permit for Discharges of Stormwater from Construction Activities within 60 days of receiving a complete notice of termination from the operator of the construction activity. Additional provisions specify that such permit coverage shall be deemed terminated 90 days after the receipt by the VSMP authority of a complete notice of termination and requires any VSMP authority receiving incomplete notice to inform the operator within a reasonable time and provide a detailed list of the missing elements.

Part I
Definitions, Purpose, and Applicability

9VAC25-870-10. 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 2.3 (§ 62.1-44.15:24 et seq.) of Chapter 3.1 of Title 62.1 of the Code of Virginia.

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

"Agreement in lieu of a stormwater management plan" means a contract between the VSMP authority and the owner or permittee that specifies methods that shall be implemented to comply with the requirements of a VSMP for the construction of a single-family residence; such contract may be executed by the VSMP authority in lieu of a stormwater management plan.

"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 State Water Control Board or its 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.

"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" or "BMP" means schedules of activities, prohibitions of practices, maintenance procedures, and other management practices, including both structural and nonstructural practices, to prevent or reduce the pollution of surface waters and groundwater systems.

"Board" means the State Water Control Board.

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

"Channel" means a natural or manmade waterway.

"Chesapeake Bay Preservation Act" means Article 2.5 (§ 62.1-44.15:67 et seq.) of Chapter 3.1 of Title 62.1 of the Code of Virginia.

"Chesapeake Bay Preservation Act land-disturbing activity" means a land-disturbing activity including clearing, grading, or excavation that results in a land disturbance equal to or greater than 2,500 square feet and less than one acre in all areas of jurisdictions designated as subject to the Chesapeake Bay Preservation Area Designation and Management Regulations (9VAC25-830) adopted pursuant to the Chesapeake Bay Preservation Act.

"Chesapeake Bay Preservation Area" means any land designated by a local government pursuant to Part III (9VAC25-830-70 et seq.) of the Chesapeake Bay Preservation Area Designation and Management Regulations and § 62.1-44.15:74 of the Chesapeake Bay Preservation Act. A Chesapeake Bay Preservation Area shall consist of a Resource Protection Area and a Resource Management Area as defined in the Chesapeake Bay Preservation Area Designation and Management Regulations (9VAC25-830).

"Chesapeake Bay watershed" means all land areas draining to the following Virginia river basins: Potomac River Basin, James River Basin, Rappahannock River Basin, Chesapeake Bay and its small coastal basins, and York River Basin.

"Common plan of development or sale" means a contiguous area where separate and distinct construction activities may be taking place at different times on different schedules.

"Comprehensive stormwater management plan" means a plan, which may be integrated with other land use plans or regulations, that specifies how the water quality components, quantity components, or both 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 June 15, 1972).

"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 BMP, stormwater facility, or other method used to minimize the discharge of pollutants to state waters.

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

"Clean Water Act" or "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 published in the Code of Federal 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 Environmental Quality.

"Development" means land disturbance and the resulting landform associated with the construction of residential, commercial, industrial, institutional, recreation, transportation, or utility facilities or structures or the clearing of land for nonagricultural or nonsilvicultural purposes. The regulation of discharges from development, for purposes of this chapter, does not include the exemptions found in 9VAC25-870-300.

"Direct discharge" means the discharge of a pollutant.

"Director" means the Director of the Department of Environmental Quality 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 state 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 state permit" means a document indicating the board's tentative decision to issue or deny, modify, revoke and reissue, terminate, or reissue a state individual or general permit. A notice of intent to deny a state individual or general permit is a type of draft state permit. A denial of a request for modification, revocation and reissuance, or termination is not a draft state permit.

"Drainage area" means a land area, water area, or both from which runoff flows to a common 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" or "EPA" means the United States Environmental Protection Agency.

"Erosion and Sediment Control Law" means Article 2.4 (§ 62.1-44.15:51 et seq.) of Chapter 3.1 of Title 62.1 of the Code of Virginia.

"ESC" means erosion and sediment control.

"Existing state permit" means for the purposes of this chapter a state permit issued by the board and currently held by a state 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 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.

"Flood fringe" means the portion of the floodplain outside the floodway that is usually covered with water from the 100-year flood or storm event. This includes, but is not limited to, the flood or floodway fringe designated by the Federal Emergency Management Agency.

"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 the area adjacent to a channel, river, stream, or other water body that is susceptible to being inundated by water normally associated with the 100-year flood or storm event. This includes, but is not limited to, the floodplain designated by the Federal Emergency Management Agency.

"Flood-prone area" means the component of a natural or restored stormwater conveyance system that is outside the main channel. Flood-prone areas may include, but are not limited to, the floodplain, the floodway, the flood fringe, wetlands, riparian buffers, or other areas adjacent to the main channel.

"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 100-year flood or storm event without cumulatively increasing the water surface elevation more than one foot. This includes, but is not limited to, the floodway designated by the Federal Emergency Management Agency.

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

"Hazardous substance" means any substance designated under the Code of Virginia or 40 CFR Part 116 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 unless specifically identified as another order.

"Illicit discharge" means any discharge to a municipal separate storm sewer that is not composed entirely of stormwater, except discharges pursuant to a separate VPDES or state permit (other than the state permit for discharges from the municipal separate storm sewer), discharges resulting from firefighting activities, and discharges identified by and in compliance with 9VAC25-870-400 D 2 c (3).

"Impervious cover" means a surface composed of material that significantly impedes or prevents natural infiltration of water into soil.

"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)."

"Inspection" means an on-site review of the project's compliance with the permit or the state permit, the VSMP, and any applicable design criteria, or an on-site review to obtain information or conduct surveys or investigations necessary in the implementation or 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 area" means any land area predominantly underlain at the surface or shallow subsurface by limestone, dolomite, or other soluble bedrock regardless of any obvious surface karst features.

"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 clearing, grading, or excavation, except that the term shall not include those exemptions specified in § 62.1-44.15:34 of the Code of Virginia.

"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 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.

"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);

2. Located in the counties listed in 40 CFR Part 122 Appendix H, 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.

"Layout" means a conceptual drawing sufficient to provide for the specified stormwater management facilities required at the time of approval.

"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; (iii) highway construction projects; (iv) construction of stormwater channels and stream restoration activities; and (v) water and sewer lines. Private subdivision roads or streets shall not be considered linear development projects.

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

"Localized flooding" means smaller scale flooding that may occur outside of a stormwater conveyance system. This may include high water, ponding, or standing water from stormwater runoff, which is likely to cause property damage or unsafe conditions.

"Main channel" means the portion of the stormwater conveyance system that contains the base flow and small frequent storm events.

"Major facility" means any 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 state permit before its expiration that is not a minor modification as defined in this regulation.

"Major municipal separate storm sewer 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.

"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);

2. Located in the counties listed in 40 CFR Part 122 Appendix I, 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.

"Minimize" means to reduce or eliminate the discharge of pollutants to the extent achievable using stormwater controls that are technologically available and economically practicable.

"Minor modification" means, for the purposes of this chapter, minor modification or amendment of an existing state permit before its expiration for the reasons listed at 40 CFR 122.63 and as specified in 9VAC25-870-640. 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 state permit modification or amendment does not substantially alter state 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 9VAC25-870-380 A 1.

"Municipal Separate Storm Sewer System Management Program" or "MS4 Program" means a management program covering the duration of a state 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 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" or "NPDES" means the national program for issuing, modifying, revoking and reissuing, terminating, monitoring and enforcing state 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 based on 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 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; however, channels designed utilizing natural channel design concepts may 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 separate VPDES or state 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 separate VPDES or state 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 state permit issued by the board to a state permit applicant that does not currently hold and has never held a state permit of that type, for that activity, at that location. An application for a new permit issued pursuant to this chapter, 9VAC25-880, or 9VAC25-890 shall not be subject to §§ 62.1-44.15:3 A and 62.1-44.15:4 D of the Code of Virginia.

"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, 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.

"Oil and gas exploration, production, processing, or treatment operations or transmission facilities" means all field activities or operations associated with exploration, production, or treatment operations, or transmission facilities, including activities necessary to prepare a site for drilling and for the movement and placement of drilling equipment, whether or not such field activities or operations may be considered to be construction activity. (33 USC § 1362(24))

"Operator" means the owner or operator of any facility or activity subject to the Act and this chapter. 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 state permit or VSMP authority 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" or "VSMP authority permit" means an approval to conduct a land-disturbing activity issued by the VSMP authority for the initiation of a land-disturbing activity after evidence of general permit coverage has been provided where applicable.

"Permittee" means the person to whom the state permit or VSMP authority permit is issued, including any owner or operator whose construction site is covered under a state construction general permit.

"Person" means any individual, corporation, partnership, association, state, municipality, commission, or political subdivision of a state, governmental body, including a federal, state, or local entity as applicable, any interstate body or any other legal entity.

"Point of discharge" means a location at which concentrated 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 groundwater 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 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.

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

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

"Publicly owned treatment works" 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.

"Qualified personnel" means a person knowledgeable in the principles and practices of erosion and sediment and stormwater management controls who possesses the skills to assess conditions at the construction site for the operator that could impact stormwater quality and quantity and to assess the effectiveness of any sediment and erosion control measures or stormwater management facilities selected to control the quality and quantity of stormwater discharges from the construction activity. For VSMP authorities this requires the use of a person who holds a certificate of competency from the board in the area of project inspection for ESC and project inspection for SWM or combined administrator for ESC and combined administrator for SWM as defined in 9VAC25-850-10 or a combination of ESC and SWM qualifications from these two areas.

"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.

"Revoked state permit" means, for the purposes of this chapter, an existing state 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.

"Runoff characteristics" includes maximum velocity, peak flow rate, volume, and flow duration.

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

"Rural Tidewater locality" means any locality that is (i) subject to the provisions of the Chesapeake Bay Preservation Act (§ 62.1-44.15:67 et seq. of the Code of Virginia) and (ii) eligible to join the Rural Coastal Virginia Community Enhancement Authority established by Chapter 76 (§ 15.2-7600 et seq.) of Title 15.2 of the Code of Virginia.

"Schedule of compliance" means a schedule of remedial measures included in a state 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.

"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 land-disturbing activity is physically located or conducted, including adjacent land used or preserved in connection with the facility or land-disturbing activity. 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, 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 an approved "total maximum daily load" (TMDL) that addresses the pollutant(s) pollutants 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) pollutants 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) pollutants 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. As of the start date in Table 1 of 9VAC25-31-1020, all certifications submitted in support of the waiver shall be submitted electronically by the owner or operator to the department in compliance with this subdivision and 40 CFR Part 3 (including, in all cases, 40 CFR Part 3 Subpart D), 9VAC25-870-370, and Part XI (9VAC25-31-950 et seq.) of the Virginia Pollutant Discharge Elimination System (VPDES) Permit Regulation. Part XI of 9VAC25-31 is not intended to undo existing requirements for electronic reporting. Prior to this date, and independent of Part XI of 9VAC25-31, permittees may be required to report electronically if specified by a particular permit.

2. Any other construction activity designated by 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 9VAC25-870-380 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.

"State" means the Commonwealth of Virginia.

"State 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 state permit.

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

"State permit" means an approval to conduct a land-disturbing activity issued by the board in the form of a state stormwater individual permit or coverage issued under a state general permit or an approval issued by the board for stormwater discharges from an MS4. Under these state permits, the Commonwealth imposes and enforces requirements pursuant to the federal Clean Water Act and regulations, the Act, and this chapter. As the mechanism that imposes and enforces requirements pursuant to the federal Clean Water Act and regulations, a state permit for stormwater discharges from an MS4 and, after June 30, 2014, a state permit for conducting a land-disturbing activity issued pursuant to the Act, are also types of Virginia Pollutant Discharge Elimination System (VPDES) Permits. State permit does not include any state permit that has not yet been the subject of final board action, such as a draft state permit. Approvals issued pursuant to this chapter, 9VAC25-880, and 9VAC25-890 are not issuances of a permit under § 62.1-44.15.01 of the Code of Virginia.

"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 a combination of drainage components that are used to convey stormwater discharge, either within or downstream of the land-disturbing activity. This includes:

1. "Manmade stormwater conveyance system" means a pipe, ditch, vegetated swale, or other stormwater conveyance system constructed by man except for restored stormwater conveyance systems;

2. "Natural stormwater conveyance system" means the main channel of a natural stream and the flood-prone area adjacent to the main channel; or

3. "Restored stormwater conveyance system" means a stormwater conveyance system that has been designed and constructed using natural channel design concepts. Restored stormwater conveyance systems include the main channel and the flood-prone area adjacent to the main channel.

"Stormwater discharge associated with construction activity" means a discharge of 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 management facility" means a control measure 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(s) document containing material for describing methods for complying with the requirements of the VSMP or this chapter. An agreement in lieu of a stormwater management plan as defined in this chapter shall be considered to meet the requirements of a stormwater management plan.

"Stormwater Pollution Prevention Plan" or "SWPPP" means a document that is prepared in accordance with good engineering practices and that identifies potential sources of pollutants that may reasonably be expected to affect the quality of stormwater discharges. A SWPPP required under a VSMP for construction activities shall identify and require the implementation of control measures, and shall include, but not be limited to the inclusion of, or the incorporation incorporate by reference of an approved erosion and sediment control plan, an approved stormwater management plan, and a pollution prevention plan.

"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 CWA, the final authority regarding the CWA jurisdiction remains with the EPA.

"SWM" means stormwater management.

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

"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.

"TMDL Action Plan" means the scheduled steps of activities that the MS4 operator will take to address the assumptions and requirements of the TMDL wasteload allocation. TMDL action plans may be implemented in multiple phases over more than one state permit cycle.

"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.

"Upset" means an exceptional incident in which there is unintentional and temporary noncompliance with technology based state 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, or in the applicable federal 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.

"Virginia Erosion and Sediment Control Program" or "VESCP" means a program approved by the board that has been established by a VESCP authority for the effective control of soil erosion, sediment deposition, and nonagricultural runoff associated with a land-disturbing activity to prevent the unreasonable degradation of properties, stream channels, waters, and other natural resources and shall include such items where applicable as local ordinances, rules, permit requirements, annual standards and specifications, policies and guidelines, technical materials, and requirements for plan review, inspection, enforcement where authorized in the Erosion and Sediment Control Act and its attendant regulations, and evaluation consistent with the requirements of the Erosion and Sediment Control Act and its attendant regulations.

"Virginia Erosion and Sediment Control Program authority" or "VESCP authority" means an authority approved by the board to operate a Virginia Erosion and Sediment Control Program. An authority may include a state entity, including the department; a federal entity; a district, county, city, or town; or for linear projects subject to annual standards and specifications, electric, natural gas and telephone utility companies, interstate and intrastate natural gas pipeline companies, railroad companies, or authorities created pursuant to § 15.2-5102 of the Code of Virginia.

"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.

"Virginia Stormwater Management Act" means Article 2.3 (§ 62.1-44.15:24 et seq.) of Chapter 3.1 of Title 62.1 of the Code of Virginia.

"Virginia Stormwater BMP Clearinghouse Website" means a website that contains detailed design standards and specifications for control measures that may be used in Virginia to comply with the requirements of the Virginia Stormwater Management Act and associated regulations.

"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" or "VSMP" means a program approved by the board after September 13, 2011, that has been established by a VSMP authority to manage the quality and quantity of runoff resulting from land-disturbing activities and shall include such items as local ordinances, rules, permit requirements, annual standards and specifications, policies and guidelines, technical materials, and requirements for plan review, inspection, enforcement, where authorized in the Act and associated regulations, and evaluation consistent with the requirements of the SWM Act and associated regulations.

"VSMP authority" means an authority approved by the board after September 13, 2011, to operate a Virginia Stormwater Management Program or the department. An authority may include a locality as set forth in § 62.1-44.15:27 of the Code of Virginia; state entity, including the department; federal entity; or, for linear projects subject to annual standards and specifications in accordance with subsection B of § 62.1-44.15:31 of the Code of Virginia, electric, natural gas, and telephone utility companies, interstate and intrastate natural gas pipeline companies, railroad companies, or authorities created pursuant to § 15.2-5102 of the Code of Virginia. Prior to approval, the board must find that the ordinances adopted by the locality's VSMP authority are consistent with the Act and this chapter including the General Permit for Discharges of Stormwater from Construction Activities (9VAC25-880).

"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 Act (§ 62.1-44.15:24 et seq. of the Code of Virginia), and the CWA (33 USC § 1251 et seq.).

"Water quantity technical criteria" means standards that establish minimum design criteria for measures to control localized flooding and stream channel erosion.

"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 water 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.

9VAC25-870-51. Chesapeake Bay Preservation Act land-disturbing activity.

A. In order to protect the quality of state waters and to control the discharge of stormwater pollutants from land-disturbing activities, runoff associated with Chesapeake Bay Preservation Act land-disturbing activities shall be regulated by localities subject to the Chesapeake Bay Preservation Act or, in the case of state and federal agency projects, the department. In regulating such land-disturbing activities in accordance with subsection B of this section, localities shall have the same authority and responsibilities as set forth in these regulations for VSMP authorities.

B. After June 30, 2014, such land-disturbing activities shall not require completion of a registration statement or require coverage under the General Permit for Discharges of Stormwater from Construction Activities but shall be subject to the following technical criteria and program and administrative requirements:

1. An erosion and sediment control plan consistent with the requirements of the Virginia Erosion and Sediment Control Law and regulations must be designed and implemented during land disturbing activities. Prior to land disturbance, this plan must be approved by either the VESCP authority or the department in accordance with the Virginia Erosion and Sediment Control Law and attendant regulations.

2. A stormwater management plan consistent with the requirements of the Virginia Stormwater Management Act and regulations must be designed and implemented during the land-disturbing activity. The stormwater management plan shall be developed and submitted in accordance with 9VAC25-870-55. Prior to land disturbance, this plan must be approved by the VSMP authority.

3. Exceptions may be requested in accordance with 9VAC25-870-57.

4. Long-term maintenance of stormwater management facilities shall be provided for and conducted in accordance with 9VAC25-870-58.

5. Water quality design criteria in 9VAC25-870-63 shall be applied to the site.

6. Water quality compliance shall be achieved in accordance with 9VAC25-870-65.

7. Channel protection and flood protection shall be achieved in accordance with 9VAC25-870-66 or as permitted by subsection B of 9VAC25-870-52.

8. Offsite compliance options in accordance with 9VAC25-870-69 shall be available to Chesapeake Bay Preservation Act land-disturbing activities.

9. Such land-disturbing activities shall be subject to the design storm and hydrologic methods set out in 9VAC25-870-72, linear development controls in 9VAC25-870-76, and criteria associated with stormwater impoundment structures or facilities in 9VAC25-870-85.

9VAC25-870-52. Chesapeake Bay Preservation Act land-disturbing activities in rural Tidewater localities.

A. Acceptance of signed and sealed plans in lieu of local plan review. In lieu of a local plan review or retaining a local certified plan reviewer, a rural Tidewater locality may accept plans and supporting calculations for erosion and sediment control and stormwater management for any land-disturbing activity equal to or greater than 2,500 square feet but less than one acre if the following criteria are met:

1. The plans are prepared and submitted by a professional licensed to engage in practice in the Commonwealth under Chapter 4 (§ 54.1-400 et seq.) or 22 (§ 54.1-2200 et seq.) of Title 54.1 of the Code of Virginia and who shall hold a certificate of competence in the appropriate subject area, as provided in § 62.1-44.15:30 of the Code of Virginia; and

2. The plan and supporting calculations are appropriately signed and sealed by the professional with a certification that states: "This plan is designed in accordance with applicable state law and regulations."

B. Tiered approach to water quantity technical criteria compliance.

1. A rural Tidewater locality may adopt the following tiered approach to water quantity management based on the percent impervious cover of the watershed in accordance with this subsection for land-disturbing activities that disturb an area of 2,500 square feet or more but less than one acre:

a. For less than 5.0% impervious cover, apply the Virginia Erosion and Sediment Control Regulation Minimum Standard 19 in effect prior to July 1, 2014, adopted by the board pursuant to Article 2.4 (§ 62.1-44.15:51 et seq.) of Chapter 3.1 of Title 62.1 of the Code of Virginia, for the protection of downstream properties and waterways from sediment deposition, erosion, and damage due to increases in volume, velocity, and peak flow rate of stormwater runoff for the stated frequency storm of 24-hour duration.

b. For 5.0% or more impervious cover but less than 7.5%, detain and release over a 24-hour period the expected rainfall resulting from the one year, 24-hour storm, which practices shall be exempt from any flow rate capacity and velocity requirements for natural or man-made channels.

c. For 7.5% impervious cover or more, apply the water quantity technical criteria in accordance with 9VAC25-870-66.

2. The establishment and conduct of the tiered approach by the locality pursuant to this section shall be subject to review by the department.

3. Prior to the adoption and implementation of the tiered approach to water quantity management, the local governing body shall:

a. Develop a watershed map that includes the following:

(1) The boundaries of the locality and each watershed located partially or wholly within the locality based on the most recent version of Virginia's 6th order National Watershed Boundary Dataset;

(2) The percentage of impervious cover within each watershed. Data provided by the Virginia Geographic Information Network (VGIN) shall be sufficient for the initial determination of impervious cover percentage at the time of the initial adoption of the map; and

(3) The locations at which the governing body expects or proposes that development should occur and may indicate the projected future percentage of impervious cover based on proposed development. The governing body may designate certain areas within a watershed in which it proposes that denser-than-average development shall occur and may designate environmentally sensitive areas in which the water quantity technical criteria in 9VAC25-870-66 shall apply.

b. After the watershed map has been developed, the governing body may then approve and adopt the map by a majority vote of its membership and publish it as the official watershed map of the locality. No official watershed map shall be adopted by the governing body or have any effect until it is approved by an ordinance duly passed by the governing body of the locality after a public hearing, preceded by public notice as required by § 15.2-2204 of the Code of Virginia. Within 30 days after adoption of the official watershed map, the governing body shall file the watershed map in the office of the clerk of the circuit court.

4. At least once per year, the governing body shall by majority vote make additions to or modifications of the official watershed map to reflect actual development projects. The governing body shall change the indication on the map of the impervious cover percentage within a watershed where the percentage has changed and shall update the map and supporting datasets with actual development project information, including single-family housing projects and any projects covered by the General VPDES Permit for Discharges of Stormwater from Construction Activities and administered by the department for opt-out localities pursuant to § 62.1-44.15:27 of the Code of Virginia. The governing body may incorporate into the official watershed map the most recent VGIN data, including data on state and federal projects that are not reviewed or approved by the locality. The governing body shall keep current its impervious cover percentage for each watershed located within the locality, as reflected in the official watershed map, and shall make the map and such percentages available to the public.

5. The locality shall notify the department and update the official watershed map within 12 months of the approval of the development plan for any project that exceeds the percent impervious cover percentage of the watershed in which it is located and causes the impervious cover percentage for the watershed to increase such that the watershed percent impervious cover is categorized by the next higher tier pursuant to subdivision B 1 of this section.

6. No official watershed map or its adopting or amending ordinance shall take precedence over any duly adopted zoning ordinance, comprehensive plan, or other local land-use ordinance, and in the case of a conflict, the official watershed map or ordinance shall yield to such land-use ordinance.

9VAC25-870-66. 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 § 62.1-44.15:28 of the Code of Virginia or as permitted in accordance with § 62.1-44.15:27.2 of the Code of Virginia. Nothing in this section shall prohibit a locality's VSMP authority from establishing a more stringent standard in accordance with § 62.1-44.15:33 of the Code of Virginia especially where more stringent requirements are necessary to address total maximum daily load requirements or to protect exceptional state waters. Compliance with the minimum standards set out in this section shall be deemed to satisfy the requirements of subdivision 19 of 9VAC25-840-40 (Minimum standards; Virginia Erosion and Sediment Control Regulations).

B. Channel protection. Concentrated stormwater flow shall be released into a stormwater conveyance system and shall meet the criteria in subdivision 1, 2, or 3 of this subsection, where applicable, from the point of discharge to a point to the limits of analysis in subdivision 4 of this subsection.

1. Manmade stormwater conveyance systems. When stormwater from a development is discharged to a manmade stormwater conveyance system, following the land-disturbing activity, either:

a. The manmade stormwater conveyance system shall convey the postdevelopment peak flow rate from the two-year 24-hour storm event without causing erosion of the system. Detention of stormwater or downstream improvements may be incorporated into the approved land-disturbing activity to meet this criterion, at the discretion of the VSMP authority; or

b. The peak discharge requirements for concentrated stormwater flow to natural stormwater conveyance systems in subdivision 3 of this subsection shall be met.

2. Restored stormwater conveyance systems. When stormwater from a development is discharged to a restored stormwater conveyance system that has been restored using natural design concepts, following the land-disturbing activity, either:

a. The development shall be consistent, in combination with other stormwater runoff, with the design parameters of the restored stormwater conveyance system that is functioning in accordance with the design objectives; or

b. The peak discharge requirements for concentrated stormwater flow to natural stormwater conveyance systems in subdivision 3 of this subsection shall be met.

3. Natural stormwater conveyance systems. When stormwater from a development is discharged to a natural stormwater conveyance system, the maximum peak flow rate from the one-year 24-hour storm following the land-disturbing activity shall be calculated either:

a. In accordance with the following methodology:

Q_Developed = I.F.*(Q_{Pre-developed}* RV_{Pre-Developed})/RV_Developed

Under no condition shall Q_Developed be greater than Q_{Pre-Developed} nor shall Q_Developed be required to be less than that calculated in the equation (Q_Forest * RV_Forest)/RV_Developed; where

I.F. (Improvement Factor) equals 0.8 for sites > 1 acre or 0.9 for sites = 1 acre.

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

RV_Developed = The volume of runoff from the site in the developed condition.

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

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

Q_Forest = The peak flow rate of runoff from the site in a forested condition.

RV_Forest = The volume of runoff from the site in a forested condition; or

b. In accordance with another methodology that is demonstrated by the VSMP authority to achieve equivalent results and is approved by the board.

4. Limits of analysis. Unless subdivision 3 of this subsection is utilized to show compliance with the channel protection criteria, stormwater conveyance systems shall be analyzed for compliance with channel protection criteria to a point where either:

a. Based on land area, the site's contributing drainage area is less than or equal to 1.0% of the total watershed area; or

b. Based on peak flow rate, the site's peak flow rate from the one-year 24-hour storm is less than or equal to 1.0% of the existing peak flow rate from the one-year 24-hour storm prior to the implementation of any stormwater quantity control measures.

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 acceptable hydrologic and hydraulic methodologies:

1. Concentrated stormwater flow to stormwater conveyance systems that currently do not experience localized flooding during the 10-year 24-hour storm event: The point of discharge releases stormwater into a stormwater conveyance system that, following the land-disturbing activity, confines the postdevelopment peak flow rate from the 10-year 24-hour storm event within the stormwater conveyance system. Detention of stormwater or downstream improvements may be incorporated into the approved land-disturbing activity to meet this criterion, at the discretion of the VSMP authority.

2. Concentrated stormwater flow to stormwater conveyance systems that currently experience localized flooding during the 10-year 24-hour storm event: The point of discharge either:

a. Confines the postdevelopment peak flow rate from the 10-year 24-hour storm event within the stormwater conveyance system to avoid the localized flooding. Detention of stormwater or downstream improvements may be incorporated into the approved land-disturbing activity to meet this criterion, at the discretion of the VSMP authority; or

b. Releases a postdevelopment peak flow rate for the 10-year 24-hour storm event that is less than the predevelopment peak flow rate from the 10-year 24-hour storm event. Downstream stormwater conveyance systems do not require any additional analysis to show compliance with flood protection criteria if this option is utilized.

3. Limits of analysis. Unless subdivision 2 b of this subsection is utilized to comply with the flood protection criteria, stormwater conveyance systems shall be analyzed for compliance with flood protection criteria to a point where:

a. The site's contributing drainage area is less than or equal to 1.0% of the total watershed area draining to a point of analysis in the downstream stormwater conveyance system;

b. Based on peak flow rate, the site's peak flow rate from the 10-year 24-hour storm event is less than or equal to 1.0% of the existing peak flow rate from the 10-year 24-hour storm event prior to the implementation of any stormwater quantity control measures; or

c. The stormwater conveyance system enters a mapped floodplain or other flood-prone area, adopted by ordinance, of any locality.

D. 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 stormwater management 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.

E. For purposes of computing predevelopment runoff, 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 VSMP authority that actual site conditions warrant such considerations.

F. Predevelopment and postdevelopment 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. Guidance provided in the Virginia Stormwater Management Handbook and on the Virginia Stormwater BMP Clearinghouse Website shall be considered appropriate practices.

9VAC25-870-103. Requirements for Chesapeake Bay Preservation Act land-disturbing activities.

A. Localities subject to the Chesapeake Bay Preservation Act shall regulate runoff associated with Chesapeake Bay Preservation Act land-disturbing activities in accordance with the following:

1. After June 30, 2014, such land-disturbing activities shall not require completion of a registration statement or require coverage under the General Permit for Discharges of Stormwater from Construction Activities but shall be subject to the technical criteria and program and administrative requirements set out in 9VAC25-870-51.

2. A local or VSMP authority permit, as applicable, shall be issued permitting the land-disturbing activity.

3. The locality shall regulate such land-disturbing activities in compliance with the:

a. Program requirements in 9VAC25-870-104;

b. Plan review requirements in 9VAC25-870-108 with the exception of subsection D of 9VAC25-870-108 or as allowed in subsection A of 9VAC25-870-52;

c. Long-term stormwater management facility requirements of 9VAC25-870-112;

d. Inspection requirements of 9VAC25-870-114 with the exception of subdivisions A 3 and A 4 of 9VAC25-870-114;

e. Enforcement components of 9VAC25-870-116;

f. Hearing requirements of 9VAC25-870-118;

g. Exception conditions of 9VAC25-870-122 excluding subsection C of 9VAC25-870-122 which is not applicable; and

h. Reporting and recordkeeping requirements of 9VAC25-870-126 with the exception of subdivision B 3 of 9VAC25-870-126.

B. A locality subject to the Chesapeake Bay Preservation Act shall adopt an ordinance that incorporates the components of this section.

C. In accordance with subdivision A 5 of § 62.1-44.15:28 of the Code of Virginia, a locality's VSMP authority may collect a permit issuance fee from the applicant of $290 and an annual maintenance fee of $50 for such land-disturbing activities.

9VAC25-870-148. Virginia stormwater management program administrative requirements.

A. A VSMP shall provide for the following:

1. Identification of the authority accepting complete registration statements and of the authorities completing plan review, plan approval, inspection, and enforcement;

2. Submission and approval of erosion and sediment control plans in accordance with the Virginia Erosion and Sediment Control Law and attendant regulations and the submission and approval of stormwater management plans;

3. Requirements to ensure compliance with 9VAC25-870-54, 9VAC25-870-55, and 9VAC25-870-56;

4. Requirements for inspections and monitoring of construction activities by the operator for compliance with local ordinances;

5. Requirements for long-term inspection and maintenance of stormwater management facilities;

6. Collection, distribution to the state if required, and expenditure of fees;

7. Enforcement procedures and civil penalties where applicable;

8. Policies and procedures to obtain and release bonds, if applicable; and

9. Procedures for complying with the applicable reporting and recordkeeping requirements in 9VAC25-870-126.

B. A locality's VSMP authority shall adopt and enforce an ordinance(s) ordinance that incorporate(s) incorporates the components set out in subdivisions 1 through 5 and 7 of subsection A of this section. Other VSMP authorities shall provide supporting documentation that incorporates the components set out in subdivisions 1 through 5 of subsection A of this section in a format acceptable to the department.

C. Notice of termination of general permit coverage.

1. A VSMP authority shall recommend that the department terminate coverage under a General VPDES Permit for Discharges of Stormwater from Construction Activities (Construction General Permit) within 60 days of receiving a complete notice of termination from the operator of the construction activity.

2. Coverage under a Construction General Permit shall be deemed to be terminated 90 days after the receipt by the VSMP authority of a complete notice of termination from the operator of the construction activity.

3. If a VSMP authority receives a notice of termination of a Construction General Permit that it determines to be incomplete, the VSMP authority shall, within a reasonable time, inform the operator of the construction activity of such incompleteness and provide the operator with a detailed list itemizing the elements of information that are missing from the notice.

DOCUMENTS INCORPORATED BY REFERENCE (9VAC25-870)

Virginia Runoff Reduction Method: Instructions & Documentation, March 28, 2011

Virginia Erosion and Sediment Control Regulation Minimum Standard 19 in effect prior to July 1, 2014