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(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 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 Director.
(c) The following activities shall be exempt from the requirements of this section, except 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.
(1) Agricultural land management activities;
(2) Additions or modifications to existing detached single-family dwellings.
(3) Activities that result in impervious surface area of less than one (1) acre 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 Management and Comprehensive Drainage Permit unless exempted under the provisions of Section 920.20(c). The Director shall issue a stormwater Management and Comprehensive Drainage Permit for plans that meet the requirements of this section and any other requirements of this article. No City grading permit, or building permit which includes work subject to the provisions of this section, shall be issued without the approval of a stormwater Management and Comprehensive Drainage Permit issued under the provisions of this article, unless the Director has issued a formal Determination stating that a stormwater Management and Comprehensive Drainage Permit is not required. Processing of the application for a stormwater Management and Comprehensive Drainage Permit shall be coordinated with other City permits as provided in Section 920.22.
(1) Any work for which a stormwater Management and Comprehensive Drainage Permit is required, shall implement the measures required by the stormwater Management and Comprehensive Drainage Permit as the first item of work to be performed, before any other aspect of the construction is begun.
(2) In the event that a stormwater Erosion and Sediment Permit is also required, the measures required by the Erosion and Sediment Permit shall be implemented first, and the measures required by the Management and Comprehensive Drainage Permit shall be implemented simultaneously, if possible, or immediately thereafter, so that no other aspect of the construction is begun until all stormwater permit requirements have been implemented.
(3) In the event that unique site conditions require some other aspect of the construction to be accomplished prior to implementation of the measures required by the stormwater Management and Comprehensive Drainage Permit, the Permittee shall be required, as a condition of the Permit, to provide and maintain temporary and/or phased measures so that the intent of this section is accomplished. In such cases, site work shall be planned and prioritized so that implementation of the full measures of the Permit shall be accomplished as soon as possible.
(4) Any permit issued under the provisions of this article shall be posted at the subject site during the time that such work is being performed, in such manner and at such place on such premises as the same may be readily seen and inspected by the agents of the City. In the event that any such permit so posted shall be removed, lost or destroyed, a duplicate thereof shall immediately be applied for from the Director.
(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. 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) For construction that results in impervious area of one (1) acre or more and less than if the ratio of impervious surface area to total site area is less than seventy-five percent (75%), 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:
1. Development name
3. Design firm
6. Vicinity map
8. Sheet numbers
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 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:
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 cross sections.
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, pertinent elevations of the stormwater management system.
2. All impervious areas shall be accurately depicted.
3. 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. 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 Manuel for acceptable means and methods.
(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 method for determining the volume necessary for detention may be chosen by the Applicant, but such choice shall remain subject to the approval of the Director. 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 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.
D. Beginning on July 1, 2013, detention structures that have not been approved for construction 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 50-year/24-hour storms. In redevelopment projects, a peak runoff rate of flow reduction of 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.
(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.
(h) 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.
(i) 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.
(j) The user of a completed new development and/or redevelopment construction shall submit to the Director within thirty (30) days of substantial project completion an "as-built" plan of the stormwater management facilities located upon the property/site.
(k) Waivers for Providing Stormwater Management.
(1) Every applicant shall provide for stormwater management as required by this article unless a waiver of these requirements is granted by the Director. A written request for waiver must be submitted to the Director in a form that he/she prescribes.
(2) The Director may not waive the minimum requirements for stormwater management of water quality protection.
(3) Any requirements beyond those described in Section 920.20(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, or that the property owner would suffer an undue hardship if required to meet the full requirements of this regulation. 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. This alternative facility must provide a level of stormwater control that is equal to or greater than that which would be afforded by the waived on-site practices and 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 extent 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.
Any mitigation measure shall provide a level of environmental protection and/or improvement that is, in the sole discretion of the Director, approximately equal to or greater than that which would have been provided by the waived practice.
(l) 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 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.
(m) Impervious areas measured for determining the requirements of this section, or for assessing compliance with the requirements of this section, shall be determined using the highest combination of proposed/constructed impervious area plus any additional proposed/actual disturbed area in excess of the proposed/constructed impervious footprint.
(n) Disturbed areas measured for determining the requirements of this section, or for assessing compliance with the requirements of this section, shall include areas for which vegetative cover has been, or will be, altered, reduced, or eliminated and for which a change in runoff characteristics may be reasonably determined.
(Ord. 13-13. Passed 6-6-13.)