(A) Purpose and Intent
The intent of the Watershed Protection Overlay is to ensure the availability of public water supplies at a safe and acceptable level of water quality for present and future residents of the Town and the surrounding region. Watershed protection measures allowed by this section include:
(1) Restriction of land uses allowed within water supply basins;
(2) Impervious area and density limitations; and
(3) Engineered stormwater control measures and the best management practices as listed in the Department of Environmental Quality State Design Manual.
(B) Applicability
(1) Designated Watersheds
The Watershed Protection Overlay is an overlay district to be applied to all lands lying within the watershed of a public water supply. The boundaries of the Watershed Protection Overlay shall be shown on the Town of Cary Official Zoning Map. The Watershed Protection Overlay consists of three sub-areas:
(a) Swift Creek Watershed;
(b) Jordan Lake Watershed; and
(c) Jordan Lake Watershed Critical Water Quality Area.
(2) Applicability to Development Activity
(a) The following types of development activity are exempt from the requirements of this Section 4.4.6:
1. Development existing prior to June 30, 1993;
2. Development on vacant lots inside of PDs approved prior to June 30, 1993;
3. Development on vacant lands in subdivisions platted prior to June 30, 1993, unless such lands have undergone a zoning change after June 30, 1993 and new development is required to submit a development plan; and
4. Redevelopment provided there is no increase in the total amount of impervious surface for a lot or development site.
(b) The requirements of this Section 4.4.6 shall apply to the following:
1. Vacant land that is rezoned from its designation in place on June 30, 1993;
2. New lands added to a planned development after June 30, 1993, even if the original planned development was approved prior to June 30, 1993;
3. Development in a planned development if the development had to be amended after June 30, 1993, to accommodate the development;
4. Any expansions to existing development in place as of June 30, 1993 (provisions are only applied to the addition, not the impervious surface in place on June 30, 1993).
(3) Sedimentation and Erosion Control
Responsible control of erosion and sedimentation is crucial to the protection of stormwater quality and the continued proper function of the measures required in this section. Requirements pertaining to sedimentation and erosion control are addressed in Section 14.4 of this Ordinance.
(C) Procedures for Development Approval
(1) Development Review
All development within the Watershed Protection Overlay shall demonstrate compliance with the requirements of this Section 4.4.6 at the time of approval of a development plan. Applicants complying with the standards of this section must also satisfy all other applicable requirements and obtain all other necessary approvals or permits under this Ordinance.
(2) Protection Measures Prerequisite to Certificate of Occupancy
A Certificate of Occupancy shall not be issued for any development in the Watershed Protection Overlay until all of the watershed protection measures required by this section have been approved and are in place on the property.
(D) Overview of High Density and Low Density Development Options
There are two (2) development options in the Watershed Protection Overlay, a Low Density Option and a High Density Option, each with different provisions related to either the Swift Creek Watershed or the Jordan Lake Watershed as well as to sub-areas within either watershed.
(1) Impervious Surfaces
The maximum allowable amount of impervious surface within a proposed development is limited based upon the Low or High Density Option, and differs from Watershed to watershed as depicted in Table 4.4-5.
(2) Calculation of Impervious Surfaces
Calculation of impervious surface area shall include the pavement area of all existing and proposed internal public and private streets, one-half (1/2) of the width of roadways on the perimeter of the project, driveways, rooftops, parking lots, patios, and all other impervious surfaces. For the purpose of calculating the impervious surface of roadways on the perimeter of a project, the ultimate pavement cross section of the roadway based on the Comprehensive Transportation Plan and any sidewalk(s) or greenway(s) along the perimeter roadway will be included in the calculation. For purposes of calculating the percentage of impervious area coverage, the total project area shall be regarded as the actual area of the property plus the area within the rights-of-way of the internal and perimeter streets included in the calculation of impervious area.
(3) Residential Density
In addition to limitations on the amount of impervious surface, the Low and High Density Development Options limit the gross residential densities of projects based upon the watershed where they are proposed, with higher densities allowed under the High Density Option as depicted in Table 4.4-5.
(4) Runoff Control
Engineered stormwater control measures intended to contain the runoff from the first one (1) inch of rainfall are required in any development utilizing the High Density Option in either watershed.
(E) Restrictions on Allowed Uses
The uses allowed within the Watershed Protection Overlay are the same as the uses permitted in the general use zoning district within which the land is located, pursuant to Table 5.1-1. However, the following uses are allowed within the overlay district only if they comply with the performance standards set forth in this Section 4.4.6.
(1) Swift Creek Watershed and the Jordan Lake Watershed
(a) All industrial service uses;
(b) All waste-related uses;
(c) Uses producing and/or storing toxic and/or hazardous materials; and
(d) Any use discharging sewage, industrial waste and/or non-process industrial waste.
(2) Jordan Lake Watershed Critical Water Quality Area
All uses set forth in paragraph (1) above; and all agricultural uses.
(F) Limitations on Impervious Surface Area and Density
(1) Low Density Option
Maximum impervious surface limits for the Low Density Option are set forth in the table below. Separate regulations are provided for the Jordan Lake and Swift Creek areas. The Jordan Lake regulations recognize two sub-areas, the Critical Area and the remainder of the watershed; while the Swift Creek regulations distinguish between three (3) different sub-areas: New Suburban, New Urban, and Existing Urban development. These sub-areas are depicted on the Town's Official Zoning Map.
Suburban-New | Urban-New | Existing Urban | ||
Residential | Non-Residential | Residential | Non-Residential | Residential and Non- Residential
|
Swift Creek Watershed
| ||||
Suburban-New | Urban-New | Existing Urban | ||
Residential | Non-Residential | Residential | Non-Residential | Residential and Non- Residential
|
Swift Creek Watershed
| ||||
Two and one-half (2.5) dwelling units per acre not to exceed twelve (12) percent impervious surface area. | Twelve (12) percent | Six (6.0)
dwelling units per acre east of Holly Springs
and Jones Franklin Roads, Greater than six (6.0) units per acre west of Holly Springs and Jones Franklin Roads, not to exceed twelve (12) percent,
impervious surface area. | Twelve (12) percent | The impervious surface of the underlying zoning of the property not to exceed
twelve (12) percent
impervious surface area. |
Jordan Lake Watershed
| ||||
Impervious surfaces shall not exceed twenty-four (24) percent of the project area, or two (2)
dwelling units
per acre; or three (3)
dwelling units
per acre and thirty-six (36) percent
impervious surface area
for projects containing streets built without curbs and gutters. | ||||
Jordan Lake Watershed Critical Area
| ||||
Non-residential and multi-family residential development's impervious surface ratios shall not exceed twenty-four (24) percent. Residential density (other than multi-family) shall not exceed two (2) dwelling units per acre. | ||||
(2) High Density Option
High Density Option development proposals may be approved, provided that the development applications are consistent with the following standards:
Suburban-New | Urban-New | Existing Urban | |||
Residential | Non-Residential | Residential | Non-Residential | Residential and Non-Residential | |
Swift Creek Watershed
| |||||
Suburban-New | Urban-New | Existing Urban | |||
Residential | Non-Residential | Residential | Non-Residential | Residential and Non-Residential | |
Swift Creek Watershed
| |||||
Maximum Impervious Surface Limits | Two and one- half (2.5)
dwelling units per acre not to exceed
thirty (30) percent
impervious surface area. | The impervious area allowed under the underlying general use zoning districts, not to exceed
thirty (30) percent
. | Six (6.0)
dwelling units per acre east of Holly Springs
and Jones Franklin Roads. Greater than six (6.0) units per acre west of Holly Springs and Jones Franklin Roads, not to exceed seventy (70) percent
impervious surface area. | The impervious area allowed under the underlying general use zoning districts, not to exceed
seventy (70) percent
. | The impervious area allowed under the underlying general use zoning districts, not to exceed
seventy (70) percent
. |
Sewer | Required | ||||
Impoundment and Maintenance | Required to contain and treat the runoff from the first one (1) inch of rainfall and to achieve a minimum of eighty-five (85) percent average annual removal for Total Suspended Solids (TSS). Public or private maintenance. [Other SCMs besides impoundments may be available; consult the Department of Environmental Quality State Design Manual.] | ||||
Jordan Lake Watershed
| |||||
Where new development exceeds the Low Density Option Standards above, stormwater control measures shall be used to control and treat runoff from the first inch of rainfall and to achieve a minimum of eighty-five (85) percent average annual removal for Total Suspended Solids (TSS). Development shall not exceed seventy (70) percent impervious surface area. | |||||
Jordan Lake Watershed Critical Area
| |||||
Where proposed development exceeds the Low Density Option Standards above, stormwater control measures are required to control and treat runoff from the first inch of rainfall and to achieve a minimum of eighty-five (85) percent average annual removal for Total Suspended Solids (TSS). Development shall not exceed fifty (50) percent impervious surface area. | |||||
(G) Engineered Stormwater Control Measures
(1) Ownership and Design Requirements
Stormwater control measures shall be owned by a property owner's association, or, for non-residential or multi-family development, the owner of the property. All stormwater control measures shall be designed by either a North Carolina registered professional engineer or landscape architect, to the extent that the N.C. General Statutes allow. Other stormwater systems shall be designed by a North Carolina registered professional with qualifications appropriate for the type of system required; these registered professionals are defined as professional engineers, landscape architects, to the extent that the N.C. General Statutes allow and land surveyors, to the extent that the design represents incidental drainage within a subdivision, as provided in N.C. General Statutes.
(2) Measures Required for High-Density Option
(a) All development under the high-density option shall use engineered stormwater control measures as a primary treatment system. Engineered stormwater control measures shall be designed for specific pollutant removal according to modeling techniques approved by the North Carolina Department of Environmental Quality. Specific requirements for these systems shall be in accordance with the State’s Minimum Design Criteria and Cary’s Standard Engineering Details and Specifications Manual.
(b) SCM’s that control stormwater on a runoff volume basis may be used in lieu of an SCM designed for specific pollutant removal in accordance with Section 4.4.6(G)(2)(a) provided that the post development volume of stormwater leaving the site is equal to or less than the predevelopment volume for the ninetieth (90th) percentile storm.
(3) Ground Cover Required
In addition to the vegetative filters required in Cary’s Standard Engineering Details and Specifications Manual, all land areas outside of the engineered stormwater control measures shall be provided with a ground cover sufficient to restrain erosion within fifteen (15) days after any land disturbance. Upon completion of the stormwater control measure, a permanent ground cover shall be established and maintained as part of the maintenance plan described in Section 4.4.6(G)(8) below.
(4) Legal Description Required
A legal description of the area containing the stormwater control measure shall be prepared and filed consistent with Section 4.4.6(G)(8) as a separate deed with the appropriate County’s Register of Deeds along with any easements necessary for general access to the stormwater control measure. The deeded area shall include sufficient area to perform inspections, maintenance, repairs and reconstruction. The deeded area shall include, but is not limited to detention pond, vegetative filters, all pipes and water control structures, berms and dikes.
(5) Computation of Total Built-Upon Area
Qualifying areas of the stormwater control measure may be considered pervious when computing total built-upon area. However, if the measure is used to compute the percentage built-upon area for one (1) site, it shall not be used to compute the built-upon area for any other site or area.
(6) Stormwater Control Measures
Stormwater Control Measures (SCM) including Regional SCM’s designed following the State Design Manual and Cary’s Standard Engineering Details and Specifications Manual, properly constructed, with all required financial assurances and maintenance agreements in place may be regarded as adequate to satisfy the requirements of the entire upstream contributory drainage basin.
(7) Establishment of a Dedicated Maintenance Account
Owners of a privately owned and maintained stormwater control measure shall establish, collect, and retain funds in a segregated account equal to ten (10) percent of the stormwater control measure’s original cost of construction as determined by a licensed Professional Engineer. Such funds shall be used solely for the purposes of maintaining, repairing, replacing, and reconstructing the owner’s stormwater control measures. The required funds shall be collected and retained in the segregated account within five (5) years from the date of the Certificate of Watershed Compliance.
(8) Certificate of Watershed Compliance
(a) Easement and Maintenance Agreement
For all development built under the high-density development option, the owner shall enter into a binding Stormwater Control Structure Access and Easement Agreement (Easement and Maintenance Agreement) with the Town. Said Easement and Maintenance Agreement shall require the owning entity to inspect, maintain, repair and, if necessary, reconstruct the stormwater control measure in accordance with the operation and maintenance plan or manual provided by the owner. The owner of the stormwater control measure shall file the Easement and Maintenance Agreement with the appropriate County’s Register of Deeds.
(b) The Stormwater Manager shall inspect the stormwater control measure after the owning entity notifies the Stormwater Manager that all construction-related work has been completed. At this inspection, the owning entity shall provide the following documents for the Stormwater Manager’s review:
1. The executed deed, related easements, maintenance agreement, and survey plat for the stormwater control measure ready for filing with the appropriate County’s Register of Deeds;
2. A certification sealed by a qualified professional stating that the stormwater control measure is complete and complies fully with the approved plans and specifications; and
3. Reproducible as built plans and/or record drawings showing the stormwater control measures.
(c) If deficiencies are found in the documents required by Section 4.4.6(G)(8)(b), the Stormwater Manager shall direct the owning entity to correct the deficiencies, make improvements, and/or correct the documents and submit proof of the corrections and/or improvements to the Stormwater Manager.
(d) Upon the Stormwater Manager’s approval of the documents, the owning entity shall file the Easement and Maintenance Agreement and survey plat with the appropriate Counties’ Register of Deeds and provide proof of recordation to the Stormwater Manager.
(f) A Certificate of Occupancy shall not be issued for the final building within the permitted development until the Stormwater Manager has issued the Certificate of Watershed Compliance.
(9) Maintenance and Inspections
(a) An operation and maintenance plan or manual shall be provided by the developer for each stormwater control measure, 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 who is responsible for those actions. The plan shall clearly indicate the steps that will be taken for restoring a stormwater control measure to design specifications if a failure occurs.
(b) The owner of each stormwater control measure shall submit a Maintenance Inspection Report annually on the anniversary date of the Certificate of Watershed Compliance to the Stormwater Manager. A qualified professional, licensed in the state of North Carolina, shall conduct the inspection. Records of inspection shall be maintained on forms approved or supplied by Cary and shall be provided to the Stormwater Manager in a timely manner.
(c) In the event the annual inspection reveals the need for corrective action or improvements, the Stormwater Manager shall notify the owning entity 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 measure and the operation and maintenance plan or manual as provided by Section 4.4.6(G)(9)(a). After all corrective actions have been taken, the qualified professional shall re-inspect the stormwater control measure and certify that the appropriate corrective actions have been taken.
(d) Landscaping and grounds management shall be the responsibility of the owning entity. However, vegetation shall not be established or allowed to mature to the extent that the integrity of the stormwater control measure is diminished or threatened, or to the extent of interfering with any easement or access to the stormwater control measure.
(e) Except for general landscaping and grounds management, the owning entity shall notify the Stormwater Manager prior to any repair or reconstruction of the stormwater control measure. All improvements shall be made consistent with the approved plans and specifications of the stormwater control measure and the operation and maintenance plan or manual. After all repairs have been completed, the owning entity shall engage the services of a qualified professional, licensed in the state of North Carolina, to inspect said improvements and to issue a report to the Stormwater Manager. The owning entity shall perform all additions, changes, or modifications noted in the inspection report supplied by the qualified professional in a timely manner.
(f) The Stormwater Manager retains the right to perform inspections, deemed necessary by the Stormwater Manager, on any stormwater control measure.
(g) Amendments to the plans and specifications of the stormwater control measure and/or the operation and maintenance plan or manual shall be submitted to the Stormwater Manager for review. Proposed changes shall be prepared by a qualified professional.
1. If the Stormwater Manager approves the proposed changes, the owning entity of the stormwater control measure shall file sealed copies of the revisions with the Office of the Stormwater Manager.
2. If the Stormwater Manager disapproves the changes, the proposal may be revised and resubmitted as a new proposal. If the proposal has not been revised and is essentially the same as that already reviewed, it shall be returned to the applicant.
(h) If the Stormwater Manager finds that the operation and maintenance plan or manual is inadequate for any reason the Stormwater Manager shall notify the owning entity of any required changes and the owning entity shall prepare and file copies of the revised agreement first with the appropriate County’s Register of Deeds. The owning entity shall then file a copy certified by the Register of Deeds with the Stormwater Manager.
(10) Appeals of any order, requirement, decision, or determination made by the Stormwater Manager pursuant to this Section 4.4.6(G) may be made to and decided by the Zoning Board of Adjustment.
(H) Clustered Development Option
Clustering of development in the Watershed Protection Overlay may be allowed as an optional configuration in either Low Density or High Density developments on a project-by-project basis. Clustering shall follow the procedures and standards set forth in Section 8.4, and is subject to the following additional criteria:
(1) The overall density and/or impervious surface coverage of the project may not exceed the density and/or impervious surface coverage allowed under either the Low Density or the High Density option. At a minimum, lot sizes shall conform to the standards of the TR district (see Chapter 6) for residential cluster development projects; however the total number of lots shall not exceed the number of lots allowed for residential subdivision development under any Chapter 4 zoning district; and
(2) Impervious surfaces shall be designed and sited to minimize stormwater runoff impacts on the receiving waters and to minimize the concentration of stormwater flow; and
(3) The remaining undeveloped portion of the tract shall remain in an undisturbed vegetated or natural state. Where the development has an established property owner's association, the title to the open space area shall be conveyed to the association. Where a property owner's association has not been established, a maintenance agreement shall be filed with the County's Register of Deeds.
(I) Modifications and Variances
Requests for relief from the requirements of this Section 4.4.6 shall be decided either by the Zoning Board of Adjustment or by the Environmental Management Commission, depending on the watershed and the type of standard from which relief is sought.
(1) Variances Granted by the Environmental Management Commission
The Environmental Management Commission shall have the sole authority to grant major variances from the provisions of this Section 4.4.6 for properties in the Jordan Lake Watershed and Jordan Lake Watershed Critical Area. For purposes of this section, a major variance is a variance from the minimum statewide watershed protection or Jordan Rules (contained in 15A NCAC Chapter 2B) that results in (a) the relaxation, by factor greater than five percent (5%) of any buffer, density or built upon area requirement under the high density option; (b) any variation in the design, maintenance or operation requirements of a wet detention pond or other approved stormwater management system; or (c) relaxation by a factor greater than ten percent (10%), of any management requirement under the low density option.
(2) Modifications Granted by the Zoning Board of Adjustment
The Zoning Board of Adjustment shall have primary, but not sole, authority to grant modifications from the provisions of this Section 4.4.6 for properties in the Swift Creek Watershed, pursuant to this Sub-section.
(a) In the Swift Creek Watershed, the Zoning Board of Adjustment may modify the standards of Section 4.4.6(F), Limitations on Impervious Area and Density, where using perimeter or adjacent roadways in the impervious surface calculation causes a development to exceed the allowed impervious surface percentage.
(b) In the Swift Creek Watershed, the Zoning Board of Adjustment may modify the standards of Section 4.4.6(F), Limitations on Impervious Area and Density, to allow impervious surface ratios greater than twelve (12) percent but less than twenty-four (24) percent. However, requests for relief greater than twenty-four (24) percent shall be forwarded for review and decision by the Environmental Management Commission.
(3) Recommendation by Zoning Board of Adjustment to the Environmental Management Commission
If an application calls for the granting of a modification as listed in paragraph (2b) or paragraph (1) above that requires a decision by the Environmental Management Commission, the Zoning Board of Adjustment shall first reach a recommendation on the modification in accord with the requirements of Section 3.19. If the Zoning Board of Adjustment decides in favor of granting the modification, the Zoning Board of Adjustment shall prepare a preliminary record of the hearing as soon as possible and forward it to the Environmental Management Commission. The preliminary record of the hearing shall include:
(a) The modification application;
(b) The hearing notices;
(c) The evidence presented;
(d) Motions, offers of proof, objections to evidence, and rulings on them;
(e) Proposed findings and exceptions;
(f) The proposed decision, including all conditions proposed to be added to the permit.
(4) Decision by the Environmental Management Commission
(a) Approval
If the Commission approves the variance as proposed or with additional conditions, the Commission shall prepare a decision and send it to the Zoning Board of Adjustment. The Zoning Board of Adjustment shall prepare a final decision in accordance with the Commission's decision.
(b) Disapproval
If the Commission denies the variance as proposed the Commission will prepare a decision and send it to the Zoning Board of Adjustment. The Zoning Board of Adjustment shall prepare a final decision in accordance with the Commission's decision.
(J) Violations; Enforcement
This Section 4.4.6 shall be enforced by the Town Manager or designee. Any person or association who fails to comply with any provision of this Section 4.4.6, or who fails to submit a report, or who submits a fraudulent or false report, shall be in violation of this Ordinance for each occurrence or non-compliance.