(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 greater than or equal to 1.0 acres including projects less than 1.0 acres that are part of a larger common plan of development or sale within the City 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 Executive Director.
(c) Agricultural land management activities shall be exempt from the requirements of this section. It shall also be noted that no activity shall be exempt from the management of the discharge of sediment or any other form of water pollution that may leave any parcel or site.
(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 this article. The Executive Director shall issue a stormwater management permit for plans that meet the requirements of this section and any other requirements of this article. No City 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 Executive 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. In redevelopment projects, a peak runoff rate of flow reduction of ten percent (10%) from the preexisting peak runoff rate of flow must be achieved. However, no reduction shall be required beyond the peak runoff rate of flow that would occur from the parcel in its natural, undeveloped state.
(g) Site design for all new and redeveloped properties shall include management measures that keep and manage on site the first one inch of rainfall from a 24-hour storm preceded by 48 hours of no measurable precipitation. This first inch shall be 100% managed on site with no discharge to surface waters except when an alternative approach is approved by the Executive Director, which includes:
(1) Stormwater is treated before release to surface waters via extended or engineered infiltration. Extended filtration practices that are designed to capture and manage up to one inch of rainfall may discharge through an underdrain system.
(2) Provide payment in lieu of onsite retention with funds collected used for stormwater projects only.
(h) Incentives exist for certain types of development can either reduce existing impervious surfaces or at least create less “accessory” impervious surfaces. As such, a reduction of 0.2 inches from the one inch runoff reduction standard shall be applied to any of the following type of development:
(1) Redevelopment.
(2) Brownfield redevelopment.
(3) High density (>7 units per acre)
(4) Vertical density (Floor to Area Ratio (FAR) of 2 or > 18 units per acre).
(5) Mixed use and transit oriented development (within ½ mile of transit).
Reductions are additive up to a maximum of 0.75 inches for a project that meets four or more criteria. In no case shall be reduction be greater than 0.75 inches.
(i) For projects requiring a stormwater permit, plans submitted to the Executive Director shall include the following information:
(1) Descriptive information:
A. Title sheet.
1. Project name.
2. Owner.
3. Design firm.
4. Legend.
5. West Virginia registered professional engineer stamp, signature and date.
6. Vicinity map with North arrow.
7. Scale.
8. Sheet numbers.
9. Date.
B. Topographical features:
1. Original contours at intervals no greater than two vertical feet.
2. Existing drainage components, i.e., streams, ponds, pipes, etc.
3. Property boundary lines.
4. Existing streets, buildings and utilities.
5. 100 year flood plain.
6. Off-site drainage entering site.
7. Original drawing either 22 inch x 34 inch or 11 inch x 17 inch and at a scale from 1 inch equals 10 feet to 1 inch equals 50 feet.
C. Site Plan.
1. Existing and proposed structures, roads, buildings, paved areas.
2. Existing and proposed stormwater management system and components including sizes, lengths, pertinent elevations, etc.
3. Where and how proposed stormwater management system will be connected to existing systems.
4. Location and grade of all swales including a typical cross section.
5. Location and design of all other Best Management Structures/Implementations.
6. 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.
7. Existing and proposed ground cover.
8. Total impervious area.
9. Control release facilities showing cross-sections and profiles.
D. Final as-built drawings:
1. Show location, length, sizes, and pertinent elevations of the stormwater management system.
2. 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 Executive Director may extend this time as deemed necessary.
Stormwater Management and Surface
(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 Executive Director.
B. The minimum “time of concentration” to be used in the calculations shall be six (6) minutes.
C. Detention volumes shall be calculated using modeling software or an approved calculation similar to the Abt and Grigg Method. 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 and 50 year/24-hour storms. In redevelopment projects, a peak runoff rate of flow reduction of 10% from the pre-existing peak runoff rate of flow must be achieved. However, no reduction shall be required beyond the peak runoff rate of flow that would occur from the parcel in its natural, undeveloped state.
(3) Design backup. Provide information on the following for review by the Executive Director:
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 information for private stormwater control facilities.
(4) Sedimentation and erosion control measures are requried. Refer to the most current edition of The West Virginia Department of Environmental Protection Sedimentation and Erosion Control Manual for acceptable means and methods.
(j) 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.
(k) 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.
(l) 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 Executive Director. The Executive 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.
(m) 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 Executive Director may halt construction on properties that do not provide satisfactory proof of compliance with this requirement.
(n) The owner of a completed new development and/or redevelopment construction shall submit to the Executive Director within thirty (30) days of substantial project completion as “as-built” plan of the stormwater management facilities located upon the property/site.
(o) For redevelopment projects for existing public streets or parking lots with construction beginning after October 31, 2016 that are greater than 5,000 square feet, runoff reduction practices shall be employed.
(p) Fee in Lieu of Stormwater Management Practices. Where approved by the Executive Director, the applicant shall be required to pay a fee in lieu of stormwater management practices, in an amount as determined by the Executive Director. This amount shall be approximately equal to the cost 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.
(Ord. 09-16. Passed 12-22-16.)