(a) The requirements and standards of this section shall apply to all new developments and redevelopment projects. The intent of these regulations is to minimize the discharge and transport of pollutants to storm drain systems and prevent the deterioration of water quality.
(b) All new developments and redevelopment projects within the Town watershed shall include stormwater management plans and comprehensive drainage plans as described in this section. These plans shall be subject to the review and approval of the Director.
(c) The following activities shall be exempt from the requirements of this section, except that no activity over 150 square feet shall be exempt from the requirement to provide an Erosion and Sediment Control Plan and to control management of the discharge of sediment or any other form of water pollution that may leave any parcel or site.
(1) Agricultural land management activities;
(2) Additions or modifications to existing detached single-family dwellings of a size less than 1,000 square feet shall not be required to detain storm water and discharge it at a reduced rate unless the municipal system is inadequate to handle such flow; and
(3) Activities that result in impervious surface area of less than 3,000 square feet, regardless of the ratio of impervious surface area to total site area, However, a phased construction project shall be measured by the size of all planned or contemplated phases. Each phase may be required to meet the requirements of this article.
(d) All new development and redevelopment subject to the provisions of this article shall be required to obtain a stormwater permit unless exempted under the provisions of Section 934.20(c). The Director shall issue a stormwater management permit for plans that meet the requirements of this section and any other requirements of this article. No Town building permit shall be issued without the submission of a stormwater permit issued under the provisions of this article.
(e) Technical, administrative or procedural matters may be modified by the Director as needed to meet the objectives and policies defined in this article, so long as such modifications are not contrary to or beyond the intent of the objectives and policies included in this article.
(f) Uniform requirements shall be applied to each regulated project site. These requirements shall be based upon the criterion that post development stormwater peak runoff rates of flow must not exceed the pre-development peak runoff rates of flow, a peak runoff rate of flow reduction of ten percent (10%) from the pre-existing peak runoff rate of flow must be achieved.
(g) For construction that results in impervious area of 3,000 square feet or more, a stormwater management and comprehensive drainage plan will be required in order to qualify for a stormwater permit. The plan shall include the following information:
(1) Descriptive information:
A. Title block with:
(i) Development name.
(ii) Owner.
(iii) Design firm.
(iv) Legend .
(v) North arrow.
(vi) Vicinity map.
(vii) Scale.
(viii) Sheet numbers.
(ix) Date.
B. Topographical features:
(i) Original contours at intervals no greater than two vertical feet.
(ii) Existing drainage components, i.e., streams, ponds, pipes, etc.
(iii) Property boundary lines.
(iv) Existing streets, buildings, and utilities.
(v) 100 year flood plain.
(vi) Off-site drainage entering site.
(vii) Original drawing no larger than 24-inch x 36-inch and at a scale from 1 inch equals 10 feet to 1 inch equals 50 feet.
C. Site plans:
Provide an Existing Condition and a Proposed Condition Site Plans
(i) Existing and proposed structures, roads, buildings, paved areas and trees.
(ii) Existing and proposed stormwater management system and components including sizes, lengths, pertinent elevations, etc.
(iii) Where and how proposed stormwater management system will be connected to existing systems.
(iv) Location and grade of all swales including cross sections.
(v) Location and design of all other Best Management Structures/Implementations.
(vi) Sediment and Erosion Control measures are required. Refer to the most current edition of the West Virginia Department of Environmental Protection Sediment and Erosion Control manual for acceptable means and methods.
(vii) Existing and proposed ground cover.
(viii) Detail and note the following for pre-existing and proposed areas of the project: Total impervious area & Total Green space. Note the percent change in both on the Proposed Site Plan and Storm Water Permit form.
(ix) Control release facilities showing cross-sections and profiles.
(iix) Provide methods for protecting existing trees and shrubs, if there are no trees or woody shrubs present on the site provide a minimum of one tree or 3 woody shrubs per 700 square feet or less of green space.
(iiix) Provide methods to be used to protect native soils and prevent compaction of soils.
D. Final as-built drawings:
(i) Show location, length, sizes, and pertinent elevations of the stormwater management system.
(ii) All impervious areas shall be accurately depicted.
(iii) Failure to provide final as-built drawings within three months of substantial project completion will cause the utility to prepare these drawings. The responsible party shall be charged for this service. The Director may extend this time as deemed necessary.
(2) Design standards.
A. Flow rates shall be calculated by use of the Rational Method unless sufficient justification for use of another method is approved by the Director.
B. The minimum "time of concentration" to be used in the calculations shall be six (6) minutes.
C. The ABT & Grigg Method shall be used to determine the volume necessary for detention. Detention structures shall be designed in such a manner that the post-construction peak runoff rate of flow shall be equal to or less than the pre-construction peak runoff rate of flow for 2-year/24-hour, 10-year/24-hour and 25-year/24-hour storms. In all projects, a peak runoff rate of flow reduction of 10% from the pre-existing peak runoff rate of flow must be achieved.
D. All sites must maintain at least 10% of the entire project in green space, further minimizing impervious surface is encouraged.
E. Projects impacting ecologically sensitive areas may be denied a permit to construct in those areas. Plans must demonstrate how these areas are to be protected.
F. Projects shall reduce or avoid hydromodification of drainage and stream channels. Projects applying to channelize or pipe drainage and/or streams will be required to provide off site mitigation or payment in lieu will be applied at a 1:2 ratio for that portion.
G. Provide methods for protecting existing trees and shrubs, if no trees or woody shrubs are present on the site, provide one tree or 3 woody shrubs per 700 square feet of green space. If it can be demonstrated that keeping existing trees and/or shrubs is not practical to the site design, provide one tree or 3 woody shrubs per 700 square feet of green space. If the green space of said project is under 300 square feet provide one tree or 3 woody shrubs.
If providing the minimum is not practical the permitee will be required to provide off site mitigation or payment in lieu will be applied at a 1:3 ratio for that portion.
H. Provide methods to be used to protect native soils and prevent compaction of soils.
(3) Design backup.
A. Calculations of volumetric runoff and peak runoff rate of flow for both pre-development and post-development.
B. Calculations for stormwater detention/retention facility and other system elements.
C. Operation and Maintenance Manual for private stormwater control facilities
(4) Sedimentation and erosion control measures are required. Refer to the most current edition of The West Virginia Department of Environmental Protection Sedimentation and Erosion Control Manual for acceptable means and methods.
(h) Starting July 2015 For any new development or redevelopment disturbing an area of an acre or greater a Stormwater Management and Comprehensive Drainage Plan must be developed that will keep and manage on site the first one inch of rainfall from a 24- hour storm preceded by 48 hours of no measureable precipitation. Runoff volume reduction can be achieved by canopy interception, soil amendments, evaporation, rainfall harvesting, engineered infiltration, extended filtration and/or evapotranspiration and any combination of the aforementioned practices. This first one inch of rainfall must be 100% managed with no discharge to surface waters, except when the permitee chooses to implement the conditions in paragraph 4 below. This can be achieved through on site utilization of practices to include dry swales, bio-retention, rain tanks and cisterns, soil amendments, roof top disconnections, permeable pavement, porous concrete, permeable pavers, reforestation, grass channels, green roofs and other practices that alone or combined will capture the first one inch of rainfall runoff volume. Extended filtration practices that are designed to capture and retain up to one inch of rainfall may discharge volume in excess of the first inch through an under drain system. An Underground Injection Control permit may be required when certain conditions are met.
(1) The following additional water quality requirements, as applicable:
a) A project that is a potential hot spot with reasonable potential for pollutant loading(s) must provide must provide water quality treatment for associated pollutants before infiltration. (such as petroleum hydrocarbons at a vehicles fueling station)
b) A project that is a potential hot spot with reasonable potential for pollutant loading(s) that cannot implement adequate preventative or water quality treatment measures to ensure compliance to ensure compliance with groundwater and/or surface water quality standards, must properly convey stormwater to a NPDES-permitted waste water treatment facility or via a licensed waste hauler to a permitted treatment and disposal facility.
(2) Incentive Standards; A reduction of 0.2 inches from the one inch runoff reduction standard may be applied to any of the following types of development. Reductions are additive up to a maximum reduction of 0.6 inches for a development that meets four or more of the criteria.
a) Redevelopment
b) Brownfield Redevelopment
c) High Density (>7 units per acre)
d) Vertical Density, (floor to area ratio (FAR) of 2 or>18 units per acre)
e) Mixed Use and Transit Oriented Development (within 1/2 mile of transit)
(NOTE: For projects that cannot meet the runoff reduction requirement of the 0.4" after incentives have been applied, two alternatives are available: Off site mitigation or payment in lieu will be applied at a 1:2 ratio for that portion .)
(3) The Stormwater Permit Application shall include:
A. Title Block With:
(i) Development name.
(ii) Owner.
(iii) Design firm.
(iv) Authorized registered professional engineer stamp, signature and date.
(v) Legend.
(vi) North arrow.
(vii) Vicinity map.
(viii) Scale.
(ix) Sheet numbers.
(x) Date.
(xi) Revision numbers and dates.
B. Topographical features:
(i) Original and proposed contours at intervals no greater than 2 vertical feet.
(ii) Existing drainage components, i.e., streams, ponds, pipes, etc.
(iii) Property boundary lines.
(iv) Existing streets, buildings, and utilities.
(v) 100 year flood plain.
(vi) Off-site drainage entering site.
(vii) Original drawing no larger than 24-inch x 36-inch and at a scale from 1 inch equals 10 feet to 1 inch equals 50 feet.
C. Site plan:
(i) Existing and proposed structures, roads, buildings, paved areas.
(ii) Existing and proposed stormwater management system and components including sizes, lengths, pertinent elevations, etc.
(iii) Where and how proposed stormwater management system will be connected to existing systems.
(iv) Location, design and grade of all BMPs including cross sections profiles with elevations of critical components.
(v) Sedimentation and erosion control measures are required. Refer to the most current edition of The West Virginia Department of Environmental Protection Sedimentation and Erosion Control Manual for acceptable means and methods.
(vi) Existing and proposed ground cover.
(vii) Control release facilities showing cross-sections and profiles.
D. Narrative and Calculations
(i) Narrative of storm water management system
(ii) Table of BMPs with target treatment volumes for drainage areas (one inch capture), volume provided, sizing and summary of performance of proposed storm water measures.
(iii) Watershed delineation for pre & post-development conditions using the Rational method, with travel times of 6 minutes (time of concentration), Cn numbers used use coefficients noted in Star City Design Manual for each drainage area pre & post, land use pre & post, peak discharge rates pre & post and soil types, if applicable, for each drainage area.
(iv) Results of soil test pits and/or borings, infiltration tests and groundwater and bedrock elevations, if applicable.
(v) Detailed Hydraulic calculations for outlet orifices, weirs, spillways, culverts, channel sizing, etc.
(vi) Show the relationship of the construction project to 303d/TMDL waters. Note the Monongahela River is impaired for fecal coliform and Popenoe Run is impaired for fecal coliform and chlorides.
(vii) Provide methods for protecting existing trees & shrubs, note the addition of trees & shrubs in landscaping plan.
(viii) Provide methods to be used to protect native soils and prevent compaction of soils.
E. Supporting Documents
(i) Maintenance Agreement, signed by all parties and recorded
(ii) Maintenance plan for each type of BMP
(iii) Documentation of other required Permits: WVDEP, WVDOT, Army Corps of Engineers, WVDHHR etc.
(iv) Documentation of "right to enter” for all storm water discharges that are not tapped directly into the Town storm system or blue lined stream.
F. Final as-built drawings:
(i) Submitted in AutoCAD DXF or DWG file format.
(ii) Show all revised contours and appropriate "spot elevations".
(iii) Show location, length, sizes, and pertinent elevations of the stormwater management system.
(iv) All impervious areas shall be accurately depicted.
(v) Failure to provide final as-built drawings within three months of substantial project completion will cause the utility to prepare these drawings. The responsible party shall be charged for this service. The Director may extend this time as deemed necessary.
(4) Applicable design standards:
Star City Design Guidance Manual - current edition (new)
WV Stormwater Design Guidance Manual -current edition
(5) Required sedimentation and erosion control measures:
WV DEP Sedimentation and Erosion Control Manual - current edition
(i) All development and/or redevelopment projects shall minimize the impact to the water environment by applying structural and/or non-structural management practices selected to address site-specific conditions. The minimum requirement for runoff water quality treatment shall be a reduction of 80% of the average post-development total suspended solids and a reduction of 40% of the average post-development phosphorus load.
(j) No construction shall be performed in a manner that will negatively impact the water environment in the vicinity of construction or in other areas, regardless of whether this impact is manifested by flow restrictions, increased runoff, diminishing channel or floodplain storage capacity, harm to aquatic life or any other manifestation of negative impact.
(k) New construction or reconstruction shall be permitted only after temporary or permanent erosion and sediment control management practices have been placed and are operational to the satisfaction of the Director. The Director may halt construction, void a permit, or take other enforcement actions consistent with this section upon a finding of inadequate erosion and sediment control management practices upon a site or property subject to the provisions of this section.
(l) All active construction sites shall be inspected by the owner no less than weekly and within 24 hours after a 0.25 inch rain event to ensure and verify effective erosion and sediment control. The owner shall maintain records of these inspections. The Director may halt construction on properties that do not provide satisfactory proof of compliance with this requirement.
(m) The owner of a completed new development and/or redevelopment construction shall submit to the Director within thirty (30) ninety (90) days of substantial project completion an "as- built" plan of the stormwater management facilities located upon the property/site.
(n) Waivers for Providing Stormwater Management.
(1) Unless waived by the Director, every applicant shall provide for stormwater management as required by this section. Request for waiver must be submitted in a form prescribed by the Director.
(2) The Director may not waive the minimum requirements for stormwater management of water quality protection.
(3) Any requirements beyond those described in Section 934.20(i) may be waived by the Director, if the Director finds that meeting the minimum on-site stormwater management requirements is not feasible due to the unique natural or existing physical characteristics of a site. A determination that requirements of this regulation cannot be met on site may not be based on the difficulty or cost of implementing measures, but must include multiple criteria that would rule out an adequate combination of the practices set forth to meet these regulations. In instances where alternatives to complete on site management of the first inch of rainfall are chosen, technical justification as to the infeasibility of on site management must be documented. To be eligible for a waiver, the applicant must also demonstrate to the satisfaction of the Director that the waiver will not result in any of the following impacts to downstream waterways:
(A) Deterioration of existing culverts, bridges, dams and other structures;
(B) Degradation of biological functions or habitat;
(C) Accelerated stream bank or streambed erosion; or
(D) Increased threat of flood damage to public health, life and/or property.
(4) Where compliance with the full requirements for on-site stormwater management is waived, the applicant shall satisfy stormwater management requirements by accomplishing a mitigation measure approved by the Director. Mitigation measures may include, but are not limited to, the following:
(A) Alternative means for on-site management of stormwater discharges that have been established in a stormwater management plan that has been approved by the Director.
(B) The creation of appropriately designed and constructed stormwater management facility or drainage improvements on other properties, public or private, that currently lack stormwater management facilities.
(i) These alternatives are available in combination or alone for up to 0.6 inches of the original 1-inch at a ratio of 1 to 1.5, than that which would be afforded by the waived on-site practices. If it is proven infeasible to manage on site a portion of all the remaining 0.4-inches, off site mitigation or payment in lieu will be applied at a 1:2 ratio for that portion. There must be a legally obligated entity responsible for the long- term operation and maintenance of the off-site practice. The Director shall, to the maximum extend practical, ensure that the benefits arising from the off-site practice shall be realized in the same basin/watershed as the waived management practice.
(C) The purchase and donation of privately owned lands to the City or the grant of an easement to the City, to be dedicated to preservation, reforestation, and/or the creation of green space, wetlands, or permanent buffer areas to protect water quality and aquatic habitat.
(o) Fee in Lieu of Stormwater Management Practices. Where the Director waives all or part of the minimum stormwater management requirements, and the applicant does not complete an approved mitigation project, the applicant shall be required to pay a fee in lieu of stormwater management practices, in an amount as determined by the Director. This amount shall be 1.5 times for the first 0.6-inches and 2 times the cost for remaining 0.4-inches of stormwater management and based on the cubic feet of storage required for stormwater management of the development in question. All of the monetary contributions shall be credited to an appropriate stormwater capital improvements program project, and shall be made by the applicant prior to the issuance of any stormwater permit for the development.
(Passed 10-11-16.)