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HomeMy WebLinkAboutORD-2010-048 Upper Eno Watershed Critical Area - Zoning Ordinance~~~~- ~2or~~ ~ ~~ AN ORDINANCE AMENDING THE ORANGE COUNTY ZONING ORDINANCE WHEREAS, on June 27, 2006 the Board of County Commissioners adopted the Efland-Mebane Small Area Plan which contains a recommendation to re-evaluate the Critical Area watershed line associated with Seven Mile Creek, and WHEREAS, County staff has analyzed the Upper Eno Watershed and the Critical and Protected areas contained therein, and WHEREAS, the Board of County Commissioners desires to continue protection of water supply watersheds to a greater standard than is required by State of North Carolina Rules, NOW THEREFORE BE IT ORDAINED by the Board of Commissioners of Orange County, North Carolina, that Sections 4.2.27 and 6.23.3, and Article 22 the Orange County Zoning Ordinance is hereby amended by adding (indicated by underlined language in red) and deleting (indicated by stricken through language in red) text as contained in this Attachment and which will amend the boundaries of the watershed overlay districts depicted on the official Zoning Atlas. ~, A Upon motion of Commissioner - ~ ~'~~~-~~ ,seconded by Commissioner ~-c~'~~~'U--.~ the foregoing Zoning ,~ Ordinance amendments were adopted this the ~ day of ~.. ~, !' ~1;~ , 2010 and shall become effective upon adoption. ~' i` Proposed Amendments to Section 4.2.27 of the Zoning Ordinance Attachment 1 (additions are underlined, deletions are in strike-through text) *4.2.27 WATERSHED PROTECTION OVERLAY DISTRICTS "Amended 1/1/94 a) Intent The purpose of the Prod-Watershed Protection Overlay Districts is to prevent significant future water quality deterioration in existing or potential future drinking water reservoirs which receive stormwater runoff from land within Orange County. Protection of all water supplies within the State in accordance with minimum standards was mandated by the Watersupply Watershed Protection Act passed by the General Assembly in 1989. The quality of water in drinking water reservoirs can be affected by human activities including farming, ebstFUMieR construction of highways and roads, subdivision development, industrial development, and other land-disturbing activities. Types of water pollutants resulting from these activities include sediment, bacterial contamination, heavy metals, synthetic organic compounds and low-level radioactivity. The intent of the etwed-Watershed Protection Overlay Districts is to apply a set of regulations involving land use and in some cases, structural best management practices which protect the watersheds by reducing the pollution from future development which enters drinking water supplies. Land use management practices involve minimum lot size and impervious surface restrictions, since impervious surfaces such as roads, roof tops and driveways are a major source of pollution. Structural best management practices allow for more intensive land use by providing for temporary detention of stormwater runoff so that pollutants may settle. b) Application Criteria The °rn�ed-Watershed Protection Overlay Districts as established in Article 4.27.2.1 4.2.27 overlay other zoning districts established in this Ordinance. The new use of any land or new structure within any r°,-�ed- Watershed Protection Overlay District shall comply with the use regulations applicable to the underlying zoning district as well as the requirements of the applicable Watershed Protection Overlay District. A Watershed Protection Overlay District will be applied to the Orange County portion of watershed which have been classified as WS-II, WS-III or WS-IV watersheds by the North Carolina Environmental Management Commission in its implementation of the Watersupply Watershed Protection Act of 1989. In accordance with the State Mandate, thirteen (13) Watershed Protection District Overlays, as listed in the following table, are hereby established. Areas designated as "Critical Area" under the Orange County designation are hereby established using the following criteria: 1 • The land area in the Upper Eno watershed (straight line distance) within one-half mile of the normal pool elevation (NPE) or nearest available contour line used for the calculation, of an existing Class I or Class II reservoir or proposed water supply reservoir designated for protection or the ridgeline of the sub-watershed, whichever is less; and • The land area within one-half mile on each side for an upstream distance of 2.5 miles (straight line distance) of any fifth order or higher stream flowing into a Class I reservoir, or the ridgeline of the sub- watershed, whichever is less; and • The land area within one-half mile on each side of a fourth order or higher stream flowing between any Class II and Class I reservoir; and • The land area within one-half mile on each side for an upstream distance of 1.5 miles (straight line distance) of a third or fourth order stream flowing directly into any Class I reservoir; and • The land area within one-half mile on each side for an upstream distance of 1.0 mile (straight line distance) of a third or fourth order stream flowing into a fourth order or higher stream that is within 1.0 miles (straight line distance) of a Class I reservoir; and • Any isolated areas within the overall critical area boundary that drain into any of the streams listed above. • Areas designated as Transition Areas on the Land Use Element Map of the Orange County Comprehensive Plan are excluded from designation as a Critical Area, except for land areas located within one-half mile from the normal pool elevation of a Class I reservoir. • The land area north of the centerline of West Ten Road and west of the centerline of the Interstate 85/U.S. 70 Connector is excluded from designation as a Critical Area except for land areas located within one- half mile from the normal pool elevation of a Class I reservoir. The designation of "Protected" applies to areas of watersheds classified as WS-II, WSIII, or WS-IV outside of areas designated as "Critical Area." 2 DISTRICT GENERAL LOCATION UNIV-CA University Lake Critical One-half mile from the normal pool elevation Area Overlay District of University Lake, or to the ridgeline of the watershed, whichever is less. UNIV-PW University Lake Protected The portion of the drainage basin of Watershed Overlay University Lake not covered by UNIV-CA. District CANE-CA Cane Creek Critical Area One-half mile from the normal pool elevation Overlay District of Cane Creek Reservoir, or to the ridgeline of the watershed, whichever is less. CANE-PW Cane Creek Protected The portion of the drainage basin of Cane Watershed Overlay Creek Reservoir not covered by CANE-CA. District U-ENO-CA Upper Eno Critical Area One-half mile from the normal pool elevation. Overlay District or to the ridgeline of the watershed, whichever is less, of the following Class I reservoirs: Corporation Lake (538' actual NPE, 540' contour line used) and Lake Ben Johnson (515' NPE and contour line used). One-half mile (straight line measurement) from the normal pool elevation, or to the ridgeline of the watershed, whichever is less of the following Class II reservoirs: Lake Orange (615' NPE and contour line used) and West Fork on the Eno (643' NPE, 640' contour line used) ; and the land area within one-half mile (straight line measurement) on each side of other streams designated for protection. These protected streams include portions of: Eno River, Seven Mile Creek, West Fork of the Eno River, East Fork of the Eno River, Rocky Run, Stream ID 1625, Stream ID 1498, Dry Run Creek, Crabtree Creek, and Stream ID 2109. — some• nn the West Fork of the Upper Enn nnrJ Seven Mile GFeeh, nr to the ririnnliRe 9f the vvv�� watershed, mhinhe"e�r i'G (Source of elevation data: Atlantic Technologies Ltd. 1998 planimetric project approved by Orange County GIS). U-ENO-PW Upper Eno Protected The portion of the Upper Eno drainage basin Watershed Overlay r a n g a Ge rn e r ati e n Lake, W est Perk of +Rh,e, Upper Gen and Seven Mile Greek not covered by U-ENO-CA. 3 L-ENO-PW Lower Eno Protected The Orange County portion of the Eno River Watershed Overlay Watershed within ten miles of the City of District Durham Emergency Water Intake east of US 501 (Roxboro Road). LITTLE-PW Little River Protected The portion of drainage basin of the Little Watershed Overlay River Reservoir which is located in Orange District County. BACK-PW Back Creek Protected The portion of the drainage basin of Back Watershed Overlay Creek which is located in Orange County. District HYCO-PW South Hyco Creek The portion of the drainage basin of South Protected Watershed Hyco Creek which is located in Orange Overlay District County. FLAT-PW Flat River Protected The portion of the drainage basin of the Flat Watershed Overlay River which is located in Orange County. District HAW-PW Haw River Protected The portion of the drainage basin for the Watershed Overlay Haw River which is located in Orange District County. JORDAN- Jordan Lake Protected The Orange County portion of the Jordan PW Watershed Overlay Lake Watershed which extends five miles District from the normal pool elevation of the impoundment. Proposed Amendments to Section 6.23.3 of the Zoning Ordinance (additions are underlined, deletions are in strike-through text) 6.23.3 STORMWATER INFILTRATION AND DETENTION As a watershed becomes more developed, the amount of impervious surface increases, causing a decrease in the rate at which stormwater runoff which can be absorbed into the soil. This results in more stormwater flowing directly into streams and other water bodies. Because this direct runoff has not been filtered through the soil, pollutants from the air and land surface enter streams and increase the potential for pollution of drinking water supplies. The effects of stormwater pollution on drinking water supplies can be minimized by one of two general approaches. First, the amount of stormwater runoff which reaches drinking water supplies can be controlled by assuring that there is adequate ground area into which water can be absorbed. This type of non-structural control is achieved through limitations on impervious surface. A second approach is to collect stormwater run-off in engineered ponds so that pollutants may settle. The water is then slowly released and contains fewer impurities when it reaches the water supply reservoir. The watershed protection standards adopted by Orange County utilize a combination of these two approaches. a) Non-Structural stormwater Control The first inch of stormwater run-off shall be controlled to the extent possible through on-site infiltration and through the use of methods which rely on natural soil properties for absorption and treatment. In order to promote infiltration of stormwater runoff into the soil and minimize direct and immediate runoff into streams and water supply impoundments, the maximum percentage of the total lot area which may be covered with an impervious surface shall be specified. This limit is referred to as the "impervious surface ratio". Impervious surface calculations for an individual development shall be cumulative for original construction and any subsequent additions. One-half of the width of any of any existing or proposed road adjacent to an individual lot shall be included as impervious surface for that lot, except in the case where an existing road was contained within a dedicated public right-of-way at the time that the watershed regulations were first applied to the watershed within which the development is located. Infiltration techniques not only remove both suspended and dissolved pollutants, but they require less maintenance, reduce flooding, promote groundwater recharge and help maintain stream flow during dry periods. Where on-site infiltration methods are utilized, areas for such purposes shall be designated on the plat and shall remain undisturbed both during and after construction. Undisturbed areas for infiltration of run-off shall also be located downslope from impervious surfaces and shall not include areas characterized by floodplains, highly erodible or 5 impervious soils, steep slopes or previously disturbed areas. Areas designated as suitable for septic tank nitrification fields may not be used for stormwater infiltration purposes. Run-off from roads, parking lots, and/or sidewalks shall be directed to undisturbed areas through use of berms, grassed diversion ditches or swales, or other acceptable means to reduce run-off velocity and filter out pollutants. b) Structural Measures Non-structural methods may not adequately control the first inch of stormwater runoff due to the amount of impervious surface proposed to be developed, and other factors such as soil type, slope, presence of floodplains and erodible soils, and/or lack of vegetative cover. In such cases, structural detention ponds, which capture stormwater for slow release through an outlet, are required. Where required, detention ponds shall be constructed in accordance with Appendix A. c) Impervious Surface and Detention Pond Requirements For all protected watersheds, there is a absolute limit on the percentage of lot area which can be covered with impervious surfaces. In some cases, detention ponds are required when the proposed impervious surface ratio exceeds a specified percentage, which is below the absolute limit. Impervious surface and detention pond requirements are as follows: 1. Residential Development 6 Amended 1/4/94; 8/21/01 DISTRICT IMPERVIOUS SURFACE/DETENTION POND REQUIREMENTS (RESIDENTIAL) UNIV-CA 6% impervious surface limit. UNIV-PW EXCEPT for all lots which existed prior to 4/2/90, which are subject to impervious surface limits as provided in the following Table (entitled Sliding Scale for Residential Impervious Surface Ratios — Univ, Cane, and Little). * BMPs cannot be used to satisfy watershed impervious surface requirements. CANE-CA 6% impervious surface limit. CANE-PW EXCEPT for lots smaller than two acres which existed U ENG-SA prior to 1/1/94, which are subject to impervious surface limits as provided in the following Table (entitled Sliding Scale for Residential Impervious Surface Ratios—Univ, Cane, and Little). * BMPs cannot be used to satisfy watershed impervious surface requirements. U-ENO-CA 6% impervious surface limit. EXCEPT for lots smaller than two--five acres which existed prior to X946/1/2010 for date of amendment ado tion , which are subject to impervious surface limits as provided in the following Table (entitled Sliding Scale for Residential Impervious Surface Ratios--Upper Eno). * BMPs cannot be used to satisfy watershed impervious surface requirements. LITTLE-PW 6% impervious surface limit. EXCEPT for lots which existed prior to 1/1/94, which are subject to impervious surface limits as provided in the following Table (entitled Sliding Scale for Residential Impervious Surface Ratios - Univ, Cane. and Little). * BMPs cannot be used to satisfy watershed impervious surface requirements. FLAT-PW 12% impervious surface limit for new and existing lots. HYCO-PW * BMPs cannot be used to satisfy watershed impervious surface requirements. U-ENO-PW 12% impervious surface limit for existing and new lots BACK-PW outside of Transition Areas as designated in the Orange County Land Use Plan. * BMPs cannot be used to satisfy watershed impervious surface requirements. 30% impervious surface limit for developments which exceed a density 1 du/acre within Transition Areas as designated in the Orange County Land Use Plan. 7 DISTRICT IMPERVIOUS SURFACE/DETENTION POND REQUIREMENTS (RESIDENTIAL) Structural BMPs are required if impervious surface exceeds 12%. L-ENO-PW 24% impervious surface limit with curb and gutter. 36% impervious surface limit without curb and gutter. BMPs cannot be used to satisfy watershed impervious surface requirements. HAW-PW 24% impervious surface limit. JORDAN-PW BMPs cannot be used to satisfy watershed impervious surface requirements. .....~ ~ ~ n~a~~uaaoaa ur u~c .~iv~ uma«~ manaycmGni rrugram ror ~nnaa wnnm ine rveuse never aasm are auowea. SLIDING SCALE FOR RESIDENTIAL IMPERVIOUS SURFACE RATIOS- SLIDING SCALE FOR RESIDENTIAL Univ Cane and Little IMPERVIOUS SURFACE RATIOS- UpperEno Lot Size ISR Square Lot Size ISR Square (Acres) Feet - -�- 6+Ac 5.0 Acres Feet 6.0 5.0 13,068 5.0 or more 6_0 13,068 5.9 5.1 13,107 4=9 6_2 13.234 5.8 5.2 13,138 4=8 6_4 13,381 5.7 5.3 13,159 4=7 6_6 13,512 5.6 5.4 13,172 4-6 6_8 13.625 5.5 5.5 13,177 4_5 7_0 13.721 5.4 5.6 13,172 44A 7_2 13,880 5.3 5.7 13,159 4_3 7_4 13,861 5.2 5.8 13,138 4_2 7_6 13.904 5.1 5.9 13,107 4_1 7_8 13.930 5.0 6.0 13,068 4_0 8_0 13,939 4.9 6.2 13,234 3=9 8_2 13,930 4.8 6.4 13,381 3_8 8_4 13.904 4.7 6.6 13,512 3=7 8_6 13.861 4.6 6.8 13,625 3_6 8_8 13.800 4.5 7.0 13,721 3_5 9_0 13.721 4.4 7.2 13,880 3_4 9_2 13.625 4.3 7.4 13,861 3_3 T44 13.512 4.2 7.6 13,904 3_2 9_6 13.382 4.1 7.8 13,930 3=1 9_8 13.234 3_0 10.0 13.068 4.0 8.0 13,939 2_9 10.2 12,885 3.9 8.2 13,930 2_8 10.4 12,685 3.8 8.4 13,904 2_7 10.6 12,467 3.7 8.6 13,861 2_6 10.8 12,232 3. 8.8 13,800 2_5 11.0 11.979 3.5 5 9.0 13,721 2_4 11.2 11,709 3.4 9.2 13,625 2_3 11.4 11,421 3.3 9.4 13,512 2_2 11.6 11,116 3.2 9.6 13,382 10. 2_1 11.8 10,794 3.1 13,234 2_p 12.0 10.454 3.0 10.0 13,068 1_9 12.2 10.097 2.9 10.2 12, 85 1_8 12.4 9.723 2.8 10.4 12,6685 1_7 12.6 9,331 2.7 10.6 12,467 1_g 12.8 8,921 2. 10.8 12,232 1_5 13.0 8,494 2.5 5 11.0 11,979 1_4 13.2 8.050 2.4 11.2 11,709 1_3 13.4 7,588 2.3 11.4 11,421 1_2 13.6 7,109 2.2 11.6 11,116 1_1 13.8 6.612 2.1 11.8 10,794 1_0 14.0 6.098 2.0 12.0 10,454 0_9 14.2 5.567 1.9 12.2 10,097 0_8 14.4 5,018 1.8 12.4 9,723 p_7 14.6 4,452 1.7 12.6 9,331 0 1. _6 14.8 3.868 12.8 8,921 0.5 15.0 3,267 1.5 5 13.0 8,494 1.4 13.2 8,050 1.3 13.4 7,588 1.2 13.6 7,109 1.1 13.8 6,612 1.0 14.0 6,098 0.9 14.2 5,567 0.8 14.4 5,018 0.76 14.6 4,452 0.6 14.8 3,868 0.5 15.0 1 3,267 9 Non-Residential Development Amended 1 /4/94: 10/19/99: 8/21 /01 DISTRICT IMPERVIOUS SURFACE/DETENTION POND REQUIREMENTS (NON-RESIDENTIAL) UNIV-CA Same as Residential (See previous Table) UNIV-PW CANE-CA 5-acre minimum lot size, with potential of up to five lots as small as two acres for lots of record October 19, 1999 (Amended 10-19-99); AND 6% impervious surface limit. * BMPs cannot be used to satisfy watershed impervious surtace requirements. U-ENO-CA 2-acre minimum lot size AND 6% impervious surface limit. * BMPs cannot be used to satisfy watershed impervious surtace re uirements. CANE-PW 5-acre minimum lot size with potential of up to five lots as small as two acres for lots of record October 19, 1999 (Amended 10-19-99); AND 50% ISR for all fire stations and solid waste collection centers; AND 12% ISR for all other non-residential uses; AND on-site infiltration of the first inch of stormwater runoff; AND a limit of 1.0% of the watershed for non-residential use (139 acres in CANE-PW). * BMPs cannot be used to satisfy watershed impervious surtace requirements. LITTLE-PW 2-acre minimum lot size AND 50% ISR for all fire stations and solid waste collection centers; AND 12% ISR for all other non-residential uses; AND on-site infiltration of the first inch of stormwater runoff; AND a limit of 1.0% of the watershed for non-residential use (139 acres in CANE-PW). * BMPs cannot be used to satisfy watershed impervious surtace re uirements. .+...r a oa ..•a•n.aaou up u•c .~~~~ mwaun mi7nd~tlllltlfll rfO9fafil iOf L8f10S WIif11O L(le IVBU$@ 1'iIVB~ K831~1 8fE 9110W@(1. 10 U-ENO-PW 70% BACK-PW ISR in Commercial and/or Industrial Nodes as designated in the Land Use Element of the Comprehensive Plan (high-density option) with structural BMPs if ISR > 12%; AND 50% ISR for all fire stations and solid waste collection centers outside of Commercial and/or Industrial Nodes as designated in the Land Use Element of the Comprehensive Plan, with structural BMPs if ISR > 12%; AND 12% ISR for all other non-residential uses outside of Commercial and/or Industrial Nodes as designated in the Land Use Element of the Comprehensive Plan (* BMPs cannot be used to satisfy watershed impervious surface requirements); AND on-site infiltration of the first inch of stormwater runoff; AND A limit of 1,151 acres of non-residential use throughout U-ENO-PW (5.0%) and 163 acres throughout BACK-PW (1%). HYCO-PW 50% ISR for all fire stations and solid waste collection centers; FLAT-PW AND 12% ISR for all other non-residential uses; AND on-site infiltration of the first inch of stormwater runoff; AND a limit of 1 % of the watershed for non-residential use (37 acres in HYCO-PW, 66 acres in FLAT-PW). * BMPs cannot be used to satisfy watershed impervious surface requirements. L-ENO-PW 70% impervious surface, with structural BMPs required when impervious surface exceeds: 24% (w/ curb and gutter); or 36% w/o curb and utter . HAW-PW 24% impervious surface limit. JORDAN-PW *BMPs cannot be used to satisfy watershed impervious surface requirements. v.nr a a.a manuaa~aa air un: aaaiunwaaCa m7fn0~ClllClll rlo9lilm Wl Lal10S WIIDIfI ills N@US@ 1"11V21 tS83111 8l8 8110WCC. 11 3. Modifications of the Impervious Surface Ratio Modifications of the Impervious Surface Ratios my be requested through one of the following provisions: a) Through variance procedures of the Board of Adjustment, as described in Article 6.23.11 b. b) Through approval and recordation of a conservation agreement, as provided in Article 4 of Chapter 121 of the N.C. General Statutes, between Orange County and a land owner that prohibits development of land in a protected watershed in perpetuity. In such cases, a modification of the required impervious surface ratios may be approved administratively but only to the extent that additional land in the same watershed is conserved or protected from development. In such instances, the land which will be subject to a conservation agreement must be adjacent to the land proposed for development and for which a modification of the impervious surface ratios is sought. As an example, a person owning a 40,000 square foot lot and subject to a 12 percent impervious surface ratio would be limited to 4,800 square feet of impervious coverage. If the person's plans called for 5,500 square feet of coverage (a difference of 700 square feet), the recording of a conservation easement on 5,833 square feet of contiguous property would satisfy the impervious surface ratio requirements. (12% of 5,833 square feet is 700 square feet.) The conservation easement shall describe the property restricted in a manner sufficient to pass title, provide that its restrictions are covenants that run with the land and, in form, be approved by the County Attorney. The conservation easement shall, upon its recording, be in the place of a first priority lien on the property (excepting current ad valorem property taxes) and shall remain so unless, with the approval of Orange County, it is released and terminated. Orange County shall require the priority of the conservation easement to be certified by and attorney-at-law, licensed to practice law in the State of North Carolina and approved to certify title to real property by a lending institution (bank or savings and loan association) doing business in Orange County. Orange County approval of a release or termination of the conservation agreement shall be declared on the document releasing or terminating the agreement. The document shall be signed by the Orange County Manager, upon approval of the Orange County Board of Commissioners. No such document shall be effective to release or terminate the conservation agreement until it is filed for registration with the Register of Deeds of Orange County. 12 Proposed Amendments to Article 22 of the Zoning Ordinance (additions are underlined, deletions are in strike-through text) ARTICLE 22 DEFINITIONS Critical Area, County Designated - The land area within one-half mile of the normal pool elevation (or designated elevation) of an existing Class II water supply reservoir, or the ridgeline of the watershed whichever is less and the land area within one-half mile of the normal pool elevation (or designated elevation) of a proposed water supply reservoir designated for protection or the ridgeline of the watershed, whichever is less; and the area within one-half mile of streams flowing into Class I reservoirs, as designated for protection within the Zoning Ordinance Amended 1/4/94 Critical Area, State Required - The land area within one-half mile of the normal pool elevation of water supply iMPGURdmepAreservoirs in which an intake is located (i.e., Class I reservoirs), or the ridgeline of the watershed, whichever is less. Reservoir, Class I - A body of water, such as a pond or lake confined by a dam or other barrier to be used for public water supply from which water flows by gravity or is pumped directly to a treatment plant or to a small intervening storage basin and thence to a treatment plant. Reservoir, Class II - A body of water, such as a pond or lake confined by a dam or other barrier to be used for public water supply from which water flows by gravity or is pumped to a Class I reservoir prior to final entrance to a water treatment plant. Stream Order - A ranking of the relative sizes of streams within a watershed based on the nature of their tributaries. The smallest unbranched tributary is called first order, the stream receiving the tributary is called second order, and so on. Amended 1/4/94 Watersupply Watershed (or Protected Watershed) Land that drains to existing reservoirs which are public water supplies or potential reservoir sites or stream intakes which have been designated for protection. All such lands have been classified by the Environmental Management Commission as WS-11, WS-III or WS-IV watersheds and require protection in accordance with the State Mandate. 13