A) General. The purpose of this chapter is to protect, maintain and enhance the public health, safety, environment and general welfare by establishing minimum requirements and procedures to control the adverse effects of increased post-development stormwater runoff and nonpoint and point source pollution associated with new development. It has been determined that proper management of construction-related and post-development stormwater runoff will minimize damage to public and private property and infrastructure; safeguard the public health, safety, and general welfare; and protect water and aquatic resources.
(a) Reference to stormwater BMP design manual. The stormwater administrator shall use the policy, criteria, and information, including technical specifications and standards, in the stormwater BMP design manual as the basis for decisions about stormwater permits and about the design, implementation and performance of structural and nonstructural stormwater best management practices (BMPs).
The stormwater BMP design manual includes a list of acceptable stormwater treatment practices, including specific design criteria for each stormwater practice. Stormwater treatment practices that are designed, constructed, and maintained in accordance with these design and sizing criteria will be presumed to meet the minimum water quality performance standards of the Phase II laws.
(b) Relationship of stormwater BMP design manual to other laws and regulations. If the specifications or guidelines of the stormwater BMP design manual are more restrictive or apply a higher standard than other laws or regulations, that fact shall not prevent application of the specifications or guidelines in the stormwater BMP design manual.
(c) Changes to standards and specifications. If the standards, specifications, guidelines, policies, criteria, or other information in the stormwater BMP design manual are amended subsequent to the submittal of an application for approval pursuant to this chapter but prior to approval, the new information shall control and shall be utilized in reviewing the application and in implementing this chapter with regard to the application.
High-density projects shall implement stormwater control measures that comply with each of the following standards:
(a) The measures shall control and treat runoff from the first inch of rain. Runoff volume drawdown time shall be a minimum of 48 hours, but not more than 120 hours.
(b) All structural stormwater treatment systems used to meet these requirements shall be designed to have a minimum of 85 percent average annual removal for total suspended solids (TSS);
(c) Stormwater shall not leave the project site at a rate greater than the predevelopment discharge rate for the ten-year, 24-hour storm;
(a) Function of BMPs as intended. The owner of each structural BMP installed pursuant to this chapter shall maintain and operate it so as to preserve and continue its function in controlling stormwater quality and quantity at the degree or amount of function for which the structural BMP was designed.
(b) Annual maintenance inspection and report. The person responsible for maintenance of any structural BMP installed pursuant to this chapter shall submit to the stormwater administrator an inspection report from one of the following persons performing services only in their area of competence: a qualified registered North Carolina professional engineer, surveyor, landscape architect, soil scientist, aquatic biologist, or person certified by the North Carolina Cooperative Extension Service for stormwater treatment practice inspection and maintenance. The inspection report shall contain all of the following:
(1) The name and address of the land owner;
(2) The recorded book and page number of the lot of each structural BMP;
(3) A statement that an inspection was made of all structural BMPs;
(4) The date the inspection was made;
(5) A statement that all inspected structural BMPs are performing properly and are in compliance with the terms and conditions of the approved maintenance agreement required by this chapter; and
(6) The original signature and seal of the engineer, surveyor, or landscape architect.
All inspection reports shall be on forms supplied by the stormwater administrator. An original inspection report shall be provided to the stormwater administrator beginning one year from the date of as-built certification and each year thereafter on or before the date of the as-built certification.