(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 Utility.
(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) Construction of a detached single family dwelling that is not part of a larger development and/or additions or modifications to and existing detached single family dwelling.
(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 section. The Utility 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 Utility 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 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 3.000 square feet or more and less than 25,000 square feet, and if the ratio of impervious surface area to total site area is less than 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;
2. Owner;
3. Design firm;
4. Legend;
5. North arrow;
6. Vicinity map;
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 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 Utility 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 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 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:
(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) For construction that results in impervious area of 25,000 square feet and greater or, if the ratio of impervious surface area to total site area is greater than 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;
2. Owner;
3. Design firm;
4. Authorized registered professional engineer stamp, signature, and date;
5. Legend;
6. North arrow;
7. Vicinity map;
8. Scale;
9. Sheet numbers;
10. Date;
11. Revision numbers and dates.
(b) Topographical features:
1. Original and proposed 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 l-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. 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;
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. Submitted in Autocadd DXF or DWG file format;
2. Show all revised contours and appropriate "spot elevations";
3. Show location, length, sizes, pertinent elevations of the stormwater management system;
4. All impervious areas shall be accurately depicted;
5. 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 Utility 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 Utility.
(b) The minimum "time of concentration" to be used in the calculations shall be six 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 of flow rate for 2-year/24-hour, 10-year/24-hour and 25-year/24-hour storms. In redevelopment projects, a peak runoff 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.
(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.
(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 flood plain 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 Utility. The Utility may halt construction, void a permit, or take other enforcement actions consistent with this ordinance upon a finding of inadequate erosion and sediment control management practices upon a site or property subject to the provisions of this article.
(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 Utility 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 Utility within 30 days of substantial project completion and "as-built" plans of the stormwater management facilities located upon the property/site.
(N) 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 Utility. A written request for waiver must be submitted to the Utility in a prescribed form.
(2) The Utility may not waive the minimum requirements for stormwater management of water quality protection.
(3) On-site storm water management requirements may be waived by the Utility if the Utility 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 Utility 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 Utility. 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 Utility.
(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 Utility 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 of Weirton or the grant of an easement to the City of Weirton, 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 Utility, approximately equal to or greater than that which would have been provided by the waived practice.
(O) Fee in lieu of stormwater management practices. Where the Utility 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 Utility. 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. 1743, passed 3-11-13)
Statutory reference:
Municipal public works, see W. V. Code §§ 8-16-5
Sewage works and stormwater works, see W. V. Code § 16-13-2, 16-13-22