15A NCAC 02H .1017. POST-CONSTRUCTION PRACTICES

(a)  Requirements for Post-Construction Practices.

(1)           Permittees, delegated programs, and regulated entities must require stormwater controls for a project that disturbs one acre or more of land, including a project that disturbs less than one acre of land that is part of a larger common plan of development or sale.  Whether an activity or project that disturbs less than one acre of land is part of a larger common plan of development shall be determined in a manner consistent with the memorandum referenced as "Guidance Interpreting Phase 2 Stormwater Requirements" from the Director of the DWQ of the DENR to Interested Parties dated 24 July 2006.  The stormwater controls shall be appropriate to the project's level of density as follows:

(A)          Low Density Option.  A project that is located within any of the coastal counties is a low density project if it meets the low density requirements of Rule .1005 of this Section.  A project that is not located within any of the coastal counties is a low density project if it contains no more than 24 percent built-upon area or no more than two dwelling units per acre.  Low density projects must use vegetated conveyances to the maximum extent practicable to transport stormwater runoff from the project.  On-site stormwater treatment devices such as infiltration areas, bioretention areas, and level spreaders may also be used as added controls for stormwater runoff. A project with an overall density at or below the low density thresholds, but containing areas with a density greater than the overall project density, may be considered low density as long as the project meets or exceeds the requirements of this Subparagraph (1)(A) and locates the higher density development in upland areas and away from surface waters and drainageways to the maximum extent practicable.

(B)          High Density Option.  A project that is located within any of the coastal counties is a high density project if it meets the high density requirements of Rule .1005 of this Section.  A project that is not located within any of the coastal counties is a high density project if it contains more than 24 percent built-upon area or more than two dwelling units per acre.  High density projects must use structural stormwater management systems that will control and treat runoff from the first one inch of rain.  The structural stormwater management system must also meet the following design standards:

(i)            Draw down the treatment volume no faster than 48 hours, but no slower than 120 hours.

(ii)           Discharge the storage volume at a rate equal to or less than the predevelopment discharge rate for the one-year, 24-hour storm.

(iii)          Remove an 85 percent average annual amount of Total Suspended Solids.

(iv)          Meet the General Engineering Design Criteria set out in Rule .1008(c) of this Section.

(v)           Wet detention ponds designed in accordance with the requirements of Item (6) of this Paragraph may be used for projects draining to Class SA waters.

(2)           Permittees, delegated programs, and regulated entities must require built-upon areas to be located at least 30 feet landward of all perennial and intermittent surface waters.  For purposes of Paragraph (a), a surface water shall be present if the feature is shown on either the most recent version of the soil survey map prepared by the Natural Resources Conservation Service of the United States Department of Agriculture or the most recent version of the 1:24,000 scale (7.5 minute) quadrangle topographic maps prepared by the United States Geologic Survey (USGS).  Relief from this requirement may be allowed when surface waters are not present in accordance with the provisions of 15A NCAC 02B .0233(3)(a).  In addition, an exception to this requirement may be pursued in accordance with Paragraph (c) of this Rule.

(3)           Permittees, delegated programs, and regulated entities must implement or require a fecal coliform reduction program that controls, to the maximum extent practicable, the sources of fecal coliform. At a minimum, the program shall include the development and implementation of an oversight program to ensure proper operation and maintenance of on-site wastewater treatment systems for domestic wastewater.  For municipalities, this program may be coordinated with local county health departments.

(4)           Permittees, delegated programs, and regulated entities must impose or require recorded restrictions and protective covenants to be recorded on the property in the Office of the Register of Deeds in the county where the property is located prior to the issuance of a certificate of occupancy in order to ensure that development activities will maintain the project consistent with approved plans.

(5)           Permittees, delegated programs, and regulated entities must implement or require an operation and maintenance plan that ensures the adequate long-term operation of the structural best management practices (BMP) required by the program.  The operation and maintenance plan must require the owner of each structural BMP to submit a maintenance inspection report on each structural BMP annually to the local program.

(6)           For areas draining to Class SA waters, permittees, delegated programs, and regulated entities must:

(A)          Use BMPs that result in the highest degree of fecal coliform die-off and control to the maximum extent practicable sources of fecal coliform while still incorporating the stormwater controls required by the project's density level.

(B)          Implement a program to control the sources of fecal coliform to the maximum extent practicable, including a pet waste management component, which may be achieved by revising an existing litter ordinance, and an on-site domestic wastewater treatment systems component to ensure proper operation and maintenance of such systems, which may be coordinated with local county health departments.

(C)          Meet the requirements of Rule .1005(a)(2) of this Section.

(7)           For areas draining to Trout Waters, permittees, delegated programs, and regulated entities must:

(A)          Use BMPs that avoid a sustained increase in the receiving water temperature, while still incorporating the stormwater controls required for the project's density level.

(B)          Allow on-site stormwater treatment devices such as infiltration areas, bioretention areas, and level spreaders as added controls.

(8)           For areas draining to Nutrient Sensitive Waters, permittees, delegated programs, and regulated entities must:

(A)          Use BMPs that reduce nutrient loading, while still incorporating the stormwater controls required for the project's density level. In areas where the Department has approved a Nutrient Sensitive Water Urban Stormwater Management Program, the provisions of that program fulfill the nutrient loading reduction requirement. Nutrient Sensitive Water Urban Stormwater Management Program requirements are found in 15A NCAC 02B .0200.

(B)          Implement a nutrient application management program for both inorganic fertilizer and organic nutrients to reduce nutrients entering waters of the State.

(9)           For post-construction requirements, a program will be deemed compliant for the areas where it is implementing any of the following programs:

(A)          Water Supply Watershed I (WS-I) – 15A NCAC 02B .0212;

(B)          Water Supply Watershed II (WS-II) – 15A NCAC 02B .0214;

(C)          Water Supply Watershed III (WS-III) – 15A NCAC 02B .0215;

(D)          Water Supply Watershed IV (WS-IV) – 15A NCAC 02B .0216;

(E)           Freshwater High Quality Waters (HQW) – Rule .1006 of this Section;

(F)           Freshwater Outstanding Resource Waters (ORW) – Rule .1007 of this Section;

(G)          The Neuse River Basin Nutrient Sensitive Waters (NSW) Management Strategy – 15A NCAC 02B .0235;

(H)          The Tar-Pamlico River Basin Nutrient Sensitive (NSW) Management Strategy – 15A NCAC 02B .0258; or

(I)            The Randleman Lake Water Supply Watershed Nutrient Management Strategy – 15A NCAC 02B .0251.

(10)         In order to fulfill the post-construction minimum measure program requirement, a permittee, delegated program, or regulated entity may use the Department's model ordinance, design its own post-construction practices based on the Department's guidance on scientific and engineering standards for BMPs, incorporate the post-construction model practices described in this act, or develop its own comprehensive watershed plan that is determined by the Department to meet the post-construction stormwater management measure required by 40 Code of Federal Regulations § 122.34(b)(5) (1 July 2003 Edition).

(11)         Nothing in this Paragraph (a) shall limit, expand, or alter the requirement that a discharge fully comply with all applicable State or federal water quality standards.

(b)  Exclusions from Post-Construction Practices.  The post-construction practices required by Paragraph (a) of this act shall not apply to any of the following:

(1)           Development in an area where the requirements of Paragraph (a) of this act are applicable that is conducted pursuant to one of the following authorizations, provided that the authorization was obtained prior to the effective date of the post-construction stormwater control requirements in the area and the authorization is valid, unexpired, unrevoked, and not otherwise terminated:

(A)          A building permit pursuant to G.S. 153A-357 or G.S. 160A-417;

(B)          A site-specific development plan as defined by G.S. 153A-344.1(b)(5) and G.S. 160A-385.1(b)(5);

(C)          A phased development plan approved pursuant to G.S. 153A-344.1 for a project located in the unincorporated area of a county that is subject to the requirements of Paragraph (a), if the Commission is responsible for implementation of the requirements of Paragraph (a), that shows:

(i)            For the initial or first phase of development, the type and intensity of use for a specific parcel or parcels, including at a minimum, the boundaries of the project and a subdivision plan that has been approved pursuant to G.S. 153A-330 through G.S. 153A-335.

(ii)           For any subsequent phase of development, sufficient detail so that implementation of the requirements of Paragraph (a) to that phase of development would require a material change in that phase of the plan.

(D)          A vested right to the development under G.S. 153A-344(b), 153A-344.1, 160A-385(b), or 160A-385.1 issued by a local government that implements Paragraph (a); or

(E)           A vested right to the development pursuant to common law.

(2)           Redevelopment as defined in Rule .1015 of this Section.

(c)  Exceptions.  The Department or an appropriate local authority, pursuant to Article 18 of G.S. 153A or Article 19 of G.S. 160A, may grant exceptions from the 30-foot landward location of built-upon area requirement as well as the deed restrictions and protective covenants requirement as follows:

(1)           An exception may be granted if the application meets all of the following criteria:

(A)          Unnecessary hardships would result from strict application of the act;

(B)          The hardships result from conditions that are peculiar to the property, such as the location, size, or topography of the property;

(C)          The hardships did not result from actions taken by the petitioner; and

(D)          The requested exception is consistent with the spirit, purpose, and intent of this act; will protect water quality; will secure public safety and welfare; and will preserve substantial justice. Merely proving that the exception would permit a greater profit from the property shall not be considered adequate justification for an exception.

(2)           Notwithstanding Item (1) of this Paragraph, exceptions shall be granted in any of the following instances:

(A)          When there is a lack of practical alternatives for a road crossing, railroad crossing, bridge, airport facility, or utility crossing as long as it is located, designed, constructed, and maintained to minimize disturbance, provide maximum nutrient removal, protect against erosion and sedimentation, have the least adverse effects on aquatic life and habitat, and protect water quality to the maximum extent practicable through the use of BMPs.

(B)          When there is a lack of practical alternatives for a stormwater management facility; a stormwater management pond; or a utility, including, but not limited to, water, sewer, or gas construction and maintenance corridor, as long as it is located 15 feet landward of all perennial and intermittent surface waters and as long as it is located, designed, constructed, and maintained to minimize disturbance, provide maximum nutrient removal, protect against erosion and sedimentation, have the least adverse effects on aquatic life and habitat, and protect water quality to the maximum extent practicable through the use of BMPs.

(C)          A lack of practical alternatives may be shown by demonstrating that, considering the potential for a reduction in size, configuration, or density of the proposed activity and all alternative designs, the basic project purpose cannot be practically accomplished in a manner which would avoid or result in less adverse impact to surface waters.

(3)           Reasonable and appropriate conditions and safeguards may be imposed upon any exception granted.

(4)           Local authorities must document the exception procedure and submit an annual report to the Department on all exception proceedings.

(5)           Appeals of the Department's exception decisions must be filed with the Office of Administrative Hearings, under G.S. 150B-23.  Appeals of a local authority's exception decisions must be made to the appropriate Board of Adjustment or other appropriate local governing body, under G.S. 160A-388 or G.S. 153A-345.

 

History Note:        Authority G.S. 143-214.1; 143-214.7; 143-215.1; 143-215.3(a)(1);

Eff. July 3, 2012.