Subpart C. Overlay Districts

The purpose of the Water Supply Watershed Protection Overlay District (WSWP) is to define the area of water supply watersheds within the County. The intent of the overlay district is to manage the uses of land and structures encompassed by water supply watersheds within the County in order to maintain the high quality of surface water in these watersheds; this being accomplished by enforcing standards that limit the impact from existing or potential sources of contamination through the regulation of average lot size and development intensity.

1. Scope. Land use within the WSWP overlay district must comply with all the requirements of both the underlying general use district and the applicable Water Supply Watershed overlay district classification. If a use or class of use is not specifically indicated as being permitted in a watershed area, such use or class of use is prohibited.
2. Establishment. This incorporates by reference the “Official Water Supply Watershed Map for Henderson County,” hereinafter “Official Water Supply Watershed Map,” and subsequent amendments thereto, showing all water supply watershed areas designated by the North Carolina Environmental Management Commission, hereinafter NCEMC. The Official Water Supply Watershed Map shall be maintained by the Planning Director and kept in the Planning Department. The water supply watershed map shall also be shown on and become part of the Official Zoning Map for the County. The rules of interpretation for the boundaries of the map (see §42-239.3 (Interpretation of Boundaries of the Water Supply Watershed Map)) apply. In addition, where any WSWP overlay district boundaries lie at a scaled distance of more than 25 feet from any parallel lot line, the location of these map boundaries shall be determined by using the scale of the map.
3. Application of Regulations.
   1. General Application. No structure or land shall hereafter be used and no development shall take place in the WSWP overlay district except in conformity with the regulations herein specified for the watershed sub-district in which it is located. All development must minimize built-upon surface area; direct stormwater away from surface waters; and incorporate best management practices to minimize water quality impacts. No area required for the purpose of complying with the provisions of this Article shall be included in the area required for another building.
   2. Exceptions.
      
      1. Existing Development. Existing development shall be subject to the regulations contained in §42-294 (Nonconforming Lots). Expansions to structures classified as “existing development” must meet the requirements of this subsection; however, the built-upon area of the existing development is not required to be included in density calculations.
      2. Lots Created as Part of Any Ordinance. Any lot or parcel created as part of any subdivision that is exempt from the requirements of this Chapter shall be subject to the land use requirements (including impervious surface requirements) of this subsection, except that such lot or parcel must meet the minimum stream buffer requirements of §42-250 (Perennial and Intermittent Surface Water Buffers) to the maximum extent practicable.
      3. Cemetery Lots. The division of a tract into plots or lots used as a cemetery.
4. Sub-Districts and Sub-District Regulations.
   1. General. The regulations of this subsection shall apply uniformly to each class or kind of structure or land located within any of the enumerated sub-district classifications. Within the sub-districts as established below, the requirements set forth in this subsection shall be complied with in addition to any other applicable general or special requirements of this Chapter.
   2. Impact on Water Quality and Public Health. No activity, situation, structure or land use shall be allowed within a WSWP overlay sub-district that poses a threat to water quality and/or the public health, safety and welfare. Such conditions may arise from inadequate on-site sewage systems which utilize ground absorption; inadequate sedimentation and erosion control measures; the improper storage or disposal of junk, trash or other refuse within a buffer area; the improper management of stormwater runoff; or any other situation found to pose a threat to water quality. The Water Quality Administrator shall monitor land use activities within the watershed areas to identify situations that may pose a threat to water quality. Where such activities are found, the Water Quality Administrator shall take any appropriate action or proceeding to restrain, correct or abate the condition and/or violation.
   3. Water Supply Watershed Protection Sub-Districts and District Purposes. Sub-districts include:
      
      1. WP-WS-I North Fork of Mills River and Bradley Creek Watershed Overlay Sub-District. The intent of the sub-district is to provide maximum protection for water supplies within essentially natural and undeveloped watersheds in public ownership by allowing only low- intensity uses. Impacts from nonpoint source pollution shall be minimized.
      2. WP-WS-II-CA Mills River Critical Area Watershed Overlay Sub-District. The intent of the sub-district is to maintain a predominately undeveloped land use intensity pattern allowing only very low-density developments.
      3. WP-WS-II-BW Colt Creek and Mills River Balance of the Watershed Overlay Sub- Districts. The purpose of the sub-district is to maintain predominately undeveloped land use intensity. Projects in this sub-district must, to the maximum extent practicable, minimize built-upon surface area; direct stormwater away from surface waters; and incorporate best management practices to minimize water quality impacts.
      4. WP-WS-III-CA Lower Mills River Critical Area Watershed Overlay Sub-District. The purpose of the sub-district is to maintain a predominantly undeveloped land use intensity pattern.
      5. WP-WS-III-BW Lower Mills River Balance of Watershed Overlay Sub-District. The intent of the sub-district is to maintain predominantly underdeveloped land use intensity. Projects in this sub-district must, to the maximum extent practicable, minimize built-upon surface area; direct stormwater away from surface waters; and incorporate best management practices to minimize water quality impacts.
      6. WP-WS-IV-CA Upper French Broad River Critical Area Watershed Overlay Sub-District. Only new development activities that are required by this Chapter to submit a soil erosion and sedimentation control plan because one or more acres of land have been disturbed are required to meet the provisions of this Chapter related to water supply watershed when located in a WS-IV watershed. New development activities within this sub-district that do not require a soil erosion and sedimentation control plan are not required to meet the water supply watershed provisions of this sub-district.
      7. WP-WS-IV-PA Upper French Broad River Protected Area Watershed Overlay Sub-District. The intent of the WP-WS-IV-PA Upper French Broad River watershed overlay sub-district is to provide protection for water quality while accommodating moderate to high land use intensity. Development projects undertaken within this sub-district may qualify for an exemption from the density and built-upon limits as set out in this section if the project meets the criteria outlined in §42-60 (Water Supply Watershed Protection Overlay District (WSWP) D (Sub-Districts and Sub-District Regulations) (6) Sedimentation and Erosion Control Exemption. For projects implementing a natural drainage and filtering system within the low-density option the built-upon limitations indicated herein below shall apply. If stormwater runoff is filtered naturally and is not passed by gutters, drains, pipes, paved swales or other similar conduits, qualification for a natural drainage and filtering system bonus shall not impose a more stringent requirement than the provisions of this Chapter regulating the subdivision of land, or the North Carolina erosion and sedimentation control permit requirements.
   4. Water Supply Watershed Protection Sub-District Regulations on Density, Built-Upon Area, Setbacks, and Stormwater.
      
      1. Low Density Option.
         1. Engineered Stormwater Controls. Not required.
         2. Average Lot Size. Average lot size shall apply to single-family development and shall be calculated excluding road right-of-way as per Table 2.14.
         3. Maximum Percent Built-Upon Limits. Maximum percent built-upon limits shall apply to multifamily residential and nonresidential development as per Table 2.14. For the purpose of calculating built-upon area, total project area shall include total acreage in the tract on which the project is to be developed.
         4. Perennial and Intermittent Surface Water Buffers. 30 feet (See §42-250 (Perennial and Intermittent Surface Water Buffers).
      2. High-Density Option. Where new development exceeds average lot size requirements or percent built-upon area under the low-density option, the development shall be considered high-density.
         1. Engineered Stormwater Controls. High-density projects are required to control runoff from the first inch of rainfall over a 24-hour period. Stormwater controls shall adhere to the requirements of §42-239 (Stormwater Management Regulations) and §42-240 (Structural and Nonstructural Stormwater BMPs Maintenance).
         2. Maximum Percent Built-Upon Limits. New high-density development shall not exceed the prescribed percent built-upon area as per Table 2.14.
         3. Perennial and Intermittent Surface Water Buffers. The requirements of §42-250 (Perennial and Intermittent Surface Water Buffers) shall apply and shall be expanded to a minimum of 100 feet landward of all perennial surface waters.
         4. Total Suspended Solids Removal Requirement. Stormwater controls shall be designed to remove 85% of TSS.

      Table 2.14. Water Supply Watershed Protection Sub-District Regulations on Density and Built-Upon Area
      Sub-District	Low-Density Option		High-Density Option	Natural Drainage & Filtering Bonus
      	Average Lot Size	Maximum Percent Built-Upon Limits	Maximum Percent Built-Upon Limits
      WP-WS-I	Not Applicable	Not Applicable	Not Applicable	Not Applicable
      WP-WS-II-CA	80,000 sq ft.	6%	24%	Not Applicable
      WP-WS-II-BW	40,000 sq ft.	12%	30%	Not Applicable
      WP-WS-III-CA	40,000 sq ft.	12%	30%	Not Applicable
      WP-WS-III-BW	20,000 sq ft.	24%	50%	Not Applicable
      WP-WS-IV-CA	20,000 sq ft.	24%	50%	Not Applicable
      WP-WS-IV-PA	20,000 sq ft. (14,250 sq ft.)	24% (36%)	70%	Yes (Low-Density Option)

   5. Water Supply Watershed Protection Sub-District Permitted Uses. Table 2.15 outlines specifically prohibited uses within each sub-district. Table 2.16 provides specifically permitted uses within each sub-district, with additional standards required as a result of water supply watershed designation. Any proposed permitted use herein must also be permitted by the underlying general use district(s) (See §42-61 (Table of Permitted and Special Uses).
      

      Table 2.15. Water Supply Watershed Protection Sub-District Prohibited Uses
      Use Type	WP WS Sub-District PR = Prohibited
      	I*	II CA	II BW	III CA	III BW	IV CA	IV PA
      LandFills	PR	PR		PR		PR
      Landfills, Discharging	PR		PR
      Landfill, Leachate Discharging	PR				PR
      Nonresidential Development	PR
      Residential Development	PR
      Sites for land application of new residuals or petroleum contaminated soils	PR	PR		PR		PR
      *Note: The only uses permissible in the WP-WS-I district are noted in Table 2.16, Water Supply Watershed Protection Sub-District Permitted Uses with additional standards

       

      Table 2.16. Water Supply Watershed Protection Sub-District Permitted Uses Additional Standards for Permitted Uses
      Use Type	WP WS Sub-District P=Permitted, PAS=Permitted with Additional Standards
      	I	II CA	II BW	III CA	III BW	IV CA	IV PA
      Agriculture, Subject to provisions of the Food Security Act of 1985 and Food, Agriculture, Conservation and trade Act of 1990 and all rules and regulations of the Soil and Water Conservation Commission.	PAS	PAS		PAS		PAS
      Agriculture, Subject to provisions of the Food Security Act of 1985 and the Food, Agriculture, Conservation and Trade Act of 1990.			PAS		PAS		PAS
      Power Transmission Lines	P
      Restricted Road Access	P
      Silviculture, Subject to the provisions of the Forest Practices Guidelines Related to Water Quality.	PAS	PAS	PAS	PAS	PAS	PAS	PAS
      Water Withdrawal, Treatment and Distribution Facilities	P

   6. Sedimentation and Erosion Control Exemption.
      
      1. Qualifying Criteria. Development projects undertaken within a WP-WS-IV-PA Upper French Broad River watershed overlay sub-district may qualify for an exemption from the density and built-upon limits as set out in this section if the project meets all of the following criteria:
         1. Requirement for Sedimentation and Erosion Control Plan. The development project does not require a sedimentation and erosion control plan and permit under the rules and regulations promulgated by the North Carolina Sedimentation Control Commission.
         2. Nonresidential. The development is nonresidential.
         3. Initial Development Activity. The development is the initial development activity on the project site or tract and is not an expansion of any improvements already existing on the project site or tract having a built- upon area as defined in this subsection.
      2. Evaluation of Criteria. In evaluating whether the development project meets the criteria listed above for the sedimentation and erosion control exemption, the following rules shall apply:
         1. Exemption Limitations. The exemption shall not be available to nonresidential subdivisions, nonresidential cluster development(s) or nonresidential development projects being developed in phases.
         2. Residential Developments. The exemption shall not be available for single-family or any other residential development projects, including general home occupations.
         3. Discontinuance of Construction. If construction of the development project is discontinued for a period of time in excess of 180 consecutive calendar days, any further construction shall be considered an expansion to improvements already existing on the project site or tract. Any such further construction shall meet the requirements of this subsection. However, only the built-upon area of said further construction and the remainder of the project site or tract shall be used in the density calculations.
         4. Damage and Destruction. Any exempted development project may be repaired/reconstructed if damaged or destroyed. Any such reconstruction or repair shall not be considered an expansion of an improvement already existing, provided that the repair/reconstruction restores the building or built-upon area to substantially the same condition and built-upon area as before any such damage or destruction. To the extent that any such repair/reconstruction enlarges the impervious surface associated with the building or built-upon area being repaired/reconstructed, the repair/reconstruction shall be considered an expansion to an exempted development project and shall be required to meet the density and built-upon limits contained in this subsection in accordance with subsection c.
      3. Exempted Expansions. Expansions to development projects which were exempted under the terms listed above shall not be exempted from the terms of this section. All such expansions shall be required to meet the requirements of this section. However, only the built-upon area of the expansion and the undeveloped area of the project site or tract shall be used in the density calculations.
5. Mixed-Use Development. In cases where both residential and nonresidential uses are proposed for one (1) lot in single ownership, such mixed-use developments may be permitted without further subdivision of the lot. However, each use must adhere to its respective density/built-upon area requirements. For purposes of this subsection, home occupations shall, be considered as residential uses.
6. Existing Development.
   1. Existing Development. Existing development may be continued and maintained subject to the provisions provided herein. Expansions to structures classified as “existing development” must meet the requirements of this section; however, only the built-upon area of the expansion and the undeveloped area of the lot are used in the built-upon calculations.
   2. Existing Vacant Lots. Existing vacant lots are lots for which plats or deeds have been recorded as of May 23, 1994 in the office of the Register of Deeds of Henderson County. An existing lot may be used for any of the uses allowed in the watershed area in which it is located provided that where the lot size is less than the minimum specified in this subsection; the Water Quality Administrator is authorized to issue a permit.
   3. Use of Land. Uses of land existing at the time of the initial adoption of watershed regulations for a particular area and where such use of the land is not permitted to be established hereafter in the watershed area in which it is located may be continued in accordance with this Chapter (see Article VIII Subpart B (Water Supply Watershed Protection)).
   4. Reconstruction of Buildings or Built-upon Areas. Any existing building or built-upon area not in conformance with the restrictions of this subsection that has been damaged or removed may be repaired and/or reconstructed, provided that the following are complied with:
      
      1. Repair or reconstruction is initiated within 12 months and completed within two (2) years of such damage.
      2. The total amount of space devoted to built-upon area may not be increased unless stormwater control that equals or exceeds the previous development is provided.