The purpose of these requirements is to provide criteria in addition to other ordinances, rules, regulation, and law to control and minimize the adverse impacts of stormwater runoff from new development and redevelopment.

(Ord. passed 10-17-2011)

   Development shall comply with the requirements of this section if any:

   (A)   New residential or nonresidential development or redevelopment disturbs more than one acre of land; and/or

   (B)   Nonresidential development that adds more than 22,000 square feet of disturbed area.

(Ord. passed 10-17-2011)

   (A)   For areas inside the water supply watershed, development shall be in accordance with §§ 153.260 through 153.262. For areas of the county that are within one mile of and drain to waters classified as High Quality Waters, development shall be in accordance with 15A NCAC 02H .1006.

   (B)   All other areas of the county are subject to Phase II Post-Construction Stormwater Requirements as established in North Carolina Session Law 2006-246. A stormwater permit issued by North Carolina Department of Environment and Natural Resources (NCDENR), Division of Water Quality is required for new development and redevelopment activities that will result in a cumulative disturbance of one or more acres of land.

   (C)   This section outlines stormwater requirements for new development and redevelopment. Redevelopment is defined as any development on previously-developed land, other than a rebuilding activity that results in no net increase in built-upon area and provides equal or greater stormwater control than the previous development. The requirements of this section are not intended to modify or repeal any other ordinance, rule, regulation, or other provision of law. The requirements of this section are in addition to the requirements of any other ordinance, rule, regulation, or other provision of law. For additional information, please see NCDENR’s Stormwater BMP Manual.

(Ord. passed 10-17-2011)

   (A)   Prior to submission of a conceptual plan, the Developer shall consult with the following to determine if an initial conference will be necessary:

      (1)   County Engineer; and

      (2)   Planning Department.

   (B)   If the scope of the proposed development, in the opinion of the County Engineer or Planning Department, is such that an initial conference will be beneficial prior to the development of plans and specifications, the developer or his or her engineer shall present, at the time of this conference, conceptual schematic or layout of the proposed stormwater management system.

(Ord. passed 10-17-2011)

   (A)   A preliminary subdivision plat or site plan (except for minor site plans as defined by this chapter) for a commercial or residential subdivision shall include a stormwater management statement, submitted as part of the required conceptual plan.

   (B)   A stormwater management statement shall include the following:

      (1)   Development name and location;

      (2)   Developer/owner and consultant contact information;

      (3)   Site description including the following:

         (a)   Vicinity map;

         (b)   USGS Topographic Map and the county’s Soil Survey indicating area of development; and

         (c)   Description of all water courses, impoundments, and wetlands on or adjacent to the site or into which stormwater directly flows.

      (4)   Statement noting whether the site is located within the conservation zoning or a watershed district;

      (5)   Impervious area calculations;

      (6)   A description of the proposed stormwater management system including:

         (a)   Best Management Practices (BMPs) and preliminary sizes and locations, including post development drainage map delineating the flows diverted to each BMP;

         (b)   Description and concept for diversion of off-site stormwater; and

         (c)   Pre-development and post-development discharges for the 10-year and 25-year storms. If the increase in the pre-development discharge is less than 10%, then an additional may not be required unless deemed necessary by the DRB.

      (7)   Downstream analysis, if required:

         (a)   Provide topography with the following identified:

            1.   Drainage areas for the development;

            2.   Drainage areas for downstream drainage structures; and/or

            3.   Provide photographs of downstream structures.

         (b)   For existing streams and ditches, the analysis should focus on increases in velocity and flooding within the stream;

         (c)   For existing culverts, the analysis should focus on increases in headwater and flooding at the structure;

         (d)   Identify the point at which the drainage area of the development or redevelopment becomes less than 10% of the total watershed;

         (e)   All negative impacts of existing improvements and developments shall be identified, if there are no negative impacts, the analysis specifically state and demonstrate that there are not adverse impacts in the increase in site runoff; and

         (f)   If downstream measures are found to be inadequate, detention or other improvements will be required to minimize downstream impacts.

(Ord. passed 10-17-2011)

   Stream buffers/setbacks shall be required water features as noted in the following table:

 

 

(Ord. passed 10-17-2011)

   (A)   All structural stormwater best management practices (BMPs) shall meet the minimum design requirements of this section, as well as those established in the most current edition of the North Carolina Department of Environment and Natural Resources, Division of Water Quality’s Stormwater Best Management Practices Manual. The use of environmentally friendly water quality controls, such as storm drain trays and pervious tree surrounds, are encouraged.

   (B)   All structural stormwater BMPs shall be designed to be aesthetically pleasing or the extent that the BMP type allows, and as defined by compliance with this chapter, and shall not include fencing unless approved by the County Engineer. Fencing may be permitted or required due to site conditions and/or under special circumstances where the public health and safety is a reasonable concern. The following are examples of site conditions which may necessitate fencing: within 50 feet of public right(s)-of-way, driveway, or parking area, and/or if the structural BMP is three or more feet deep.

      (1)   All fences shall meet the requirements of this chapter, as applicable.

      (2)   In cases where chain link fencing is permitted, such fencing shall be coated.

   (C)   (1)   Drought tolerant species of vegetation and warm weather grasses shall be utilized on the BMPs.

      (2)   Vegetation shall be required around perimeter slopes but shall not be planted on the structural BMP dam.

      (3)   Plantings shall be in a single row when medium sized trees are used and shall be in two rows when small trees and shrubs are utilized.

   (D)   Side slopes shall be stabilized with vegetation and with a slope no steeper than 3:1 ratio.

   (E)   As-built drawings shall be submitted to the county for review prior to issuance of a certificate of occupancy for the site.

(Ord. passed 10-17-2011)

   (A)   General. When stormwater control measures are installed voluntarily or are required by this chapter but not by the state, such as through the downstream analysis process, the following criteria shall be adhered to. As required by this section, the operation and maintenance agreement shall be submitted with the final plat or site plan as part of the submittal materials, as applicable. Failure to comply with the requirements of this section, or maintain those improvements required by this section, shall be deemed a violation of this chapter.

   (B)   Operation and maintenance agreement required. The permit applicant(s) shall enter into the binding operation and maintenance agreement (O&M agreement) between all the interests in the development. This Agreement shall require the owner(s)/applicant(s) to maintain, repair, and if necessary, reconstruct the stormwater control structure in accordance with the operation management plan or manual, as provided. The owner(s) shall file the operation and maintenance agreement with the county’s Register of Deeds. The obligations incurred as part of the required O&M agreement by owner(s) and applicant(s) are appurtenant and run with the property, and shall be binding upon all subsequent owners, successors, and assigns of the project or any parcel thereof.

   (C)   Operation and maintenance plan required. An operation and maintenance plan or manual shall be provided by the owner(s) for each stormwater control structure, indicating what operation and maintenance actions are needed, what specific quantitative criteria will be used for determining when those actions are to be taken and, consistent with the operations maintenance agreement, who is responsible for those actions. The plan shall clearly indicate the steps that will be taken for restoring a stormwater control structure to design specifications if a failure occurs.

   (D)   Landscaping and grounds maintenance. Landscaping and grounds management shall be the responsibility of the owner(s). However, vegetation shall not be established or allowed to mature to the extent that the integrity of the control structure is diminished or threatened, or to the extent of interfering with any easement or access to the stormwater control structure.

   (E)   Repair or reconstruction. Except for general landscaping and grounds management, the owning entity shall notify the county’s Engineer and the state’s Department of Environment and Natural Resources (NCDENR) prior to any repair or reconstruction of the stormwater control structure. All improvements shall be made consistent with the approved plans and specifications of the stormwater control structure and the operation and maintenance plan or manual. After notification by the owner(s), the County Engineer shall inspect the completed improvements and shall inform the owner(s) of any required additions, changes, or modifications and of the time period to complete the improvements.

   (F)   Amendments to plans and specifications.

      (1)   Minor amendments. Amendments to the plans and specifications of the stormwater control structure and/or the operation and maintenance plan or manual shall be approved by the County Engineer, provided that the changes do not involve a change in the size or location of the structure. Proposed changes shall be prepared by a professional state engineer or landscape architect (to the extent that the G.S. Chapter 89A allows) and submitted to and reviewed by the County Engineer.

         (a)   If the County Engineer approves the proposed changes, the owner(s) of the stormwater control structure shall file sealed copies of the revisions with the Administrator and County Engineer.

         (b)   If the County Engineer disapproves the changes, the proposal may be revised and resubmitted as a new proposal.

      (2)   Major amendments. Proposed changes shall be prepared by a professional state engineer or landscape architect (to the extent that the G.S. Chapter 89A allows) and submitted to, and reviewed by the County Engineer and NCDENR. Amendments to the plans and specifications of the stormwater control structure and/or the operation and maintenance plan or manual that involve a change in the size or location shall be approved by the County Engineer and NCDENR.

   (G)   Revision of plan required if found to be inadequate. If the County Engineer finds that the operation and maintenance plan or manual is inadequate for any reason, the Administrator shall notify the owner(s) of any required changes. Once the revised plan or manual has been deemed adequate, the owner(s) shall prepare and file copies of the revised agreement with the county’s Register of Deeds, the County Engineer, and the Administrator of this chapter.

   (H)   Inspection by County Engineer. The stormwater control structure shall be inspected by the County Engineer, after the owner(s) notifies the Administrator that all work has been completed and prior to issuance of a certificate of occupancy (CO). At this inspection, the owner(s) shall provide:

      (1)   The signed deed, related easements, and survey plat for the stormwater control structure ready for filing with the county’s Register of Deeds; and

      (2)   A certification sealed by a professional state engineer or landscape architect (to the extent that the G.S. Chapter 89A allows) stating that the stormwater control structure is complete and consistent with the approved plans and specifications.

   (I)   Annual inspection required.

      (1)   All stormwater control structures shall be inspected at least once on an annual basis to determine whether the controls are performing as designed and intended. It shall be the responsibility of the property owner(s) to ensure such inspection is performed. Records of inspections shall be maintained on forms approved or supplied by NCDENR. Annual inspections shall begin within one year of the filing date of the deed for the stormwater control structure.

      (2)   In the event that the County Engineer discovers the need for corrective action or improvements, he or she shall notify the Administrator who shall notify the owner(s) of the needed improvements and the date by which the corrective action is to be completed. All improvements shall be made consistent with the plans and specifications of the stormwater control structure and the operation plan or manual. After notification by the owner(s), the County Engineer shall inspect and approve the completed improvements.

(Ord. passed 10-17-2011)

   The following guidelines shall be used for street and local drainage within the development of a subdivision:

   (A)   Proposed stormwater channels shall be designed in accordance with the most current edition of the North Carolina Erosion and Sediment Control Planning and Design Manual;

   (B)   Channels shall provide positive drainage. The minimum slope shall be 0.5%;

   (C)   The minimum pipe diameter allowed, including driveway pipe, is 15 inches;

   (D)   Acceptable pipe materials outside of NCDOT right-of-way include Class III reinforced concrete pipe and HOPE, PASHTO M294 — corrugated exterior/smooth interior pipe (Type S). No HOPE end treatments are allowed. Reinforced concrete pipe/headwall shall be used for all end treatments. Pipe shall be installed according to the manufacturer’s requirements. Corrugated metal pipe is not allowed. Pipe inside NCDOT right-of-way shall be in accordance with Subdivision Roads Minimum Construction Standards published by NCDOT;

   (E)   Minimum cover for all pipes located outside traffic areas is one-half foot. Minimum cover for all pipes located in proposed traffic areas is one foot;

   (F)   At utility crossings, the minimum vertical separation between storm drainage and water and sanitary sewer lines shall be 24 inches or in accordance with 15A NCAC 2T .0305, whichever is more stringent;

   (G)   Storm structures are required where there is a change in pipe size, a change in grade, or changes in horizontal alignment greater than 45 degrees. All structures shall allow for access to the storm drainage system with a removable lid or grate;

   (H)   All local drainage systems shall be designed to convey the ten-year design storm;

   (I)   The minimum design storm frequency for cross drainage for streets shall be in accordance with the current edition of Subdivision Roads Minimum Construction Standards published by NCDOT; and

   (J)   All curb and gutter shall meet NCDOT, Division of Highways standards. Curb inlet and storm drainage design shall be in accordance with requirements outlined in NCDOT’s Best Management Practices for Construction and Maintenance Activities.

(Ord. passed 10-17-2011)

   (A)   In addition to the construction plan requirements for water and sewer, stormwater management plans showing grading and drainage shall be submitted. One complete set of development plans signed and sealed by a professional state land surveyor or engineer or state registered landscape architect shall be submitted.

   (B)   The following information shall be provided on the site specific stormwater management plans:

      (1)   Erosion control measures and details;

      (2)   Detailed topographic information. A minimum of two-foot contours is required. Vertical datum shall be provided;

      (3)   Storm sewer profiles or design tables indicating the top of structure, invert elevations, and pipe slope;

      (4)   The 100-year floodplain boundaries and elevations from the most recent FIRM;

      (5)   All jurisdictional wetland boundaries on-site;

      (6)   All proposed stormwater management facilities;

      (7)   All existing stormwater management facilities should be shown. Existing structures shall be labeled with invert, size, and material;

      (8)   Construction detail for improvements; and

      (9)   Drainage easements.

   (C)   (1)   With the construction drawings, a revised stormwater management statement shall be submitted, if required.

      (2)   A copy of submittal for stormwater permit and the submittal for erosion control plan, if required, shall be submitted.

(Ord. passed 10-17-2011)

   (A)   Certification shall be provided by a professional state land surveyor or engineer, or registered landscape architect, for the “as-built” plans.

   (B)   The certification to be made is provided by this chapter, and should be sealed signed and dated and submitted with “as-built” drawings and the final plat.

(Ord. passed 10-17-2011)