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HomeMy WebLinkAboutZTA201200012 PresentationZTA 2012 - 12 Critical Slopes Board of Supervisors November 712012 Current Situation • All slopes of 25% or greater are defined as Critical Slopes. • Disturbance of Critical Slopes requires a special exception. • Certain activities are exempt from critical slopes regulations. Key Concepts • Proposal only affects the development areas. • No expansion of areas designated as critical slopes. • All critical slopes retain protection. • Protection is tiered. • Creation of an overlay district designating "Preserved" and "Managed" • "Preserved" slopes may not be disturbed except for exempt activities. • "Managed" slopes may be disturbed by right, subject to applicable performance standards. • Certain activities would be exempt from the applicable critical slopes regulations in both the Preserved and Managed areas. Factors which tends to designate an area as Preserved or Managed: Preserved Areas Managed Areas • The slopes are part of a system of The contiguous area of critical slopes associated with a water feature. slopes is limited or fragmented. • The slopes are part of a hillside system. • The slopes are identified as a resource in the Open Space Plan. • The slopes are identified as a resource in the Comprehensive Plan. • The slopes may be of significant value to the Entrance Corridor District. • The slopes are a contiguous area of 10,000 square feet or more or a close grouping of slopes less than 10,000 square feet. • The slopes are shown to be preserved by a prior County action. • The slopes are not associated with a water feature. • The slopes are not natural. • The slopes have been significantly disturbed prior to June 1, 2012. • The slopes are located within previously approved single family residential lots. • The slopes are shown to be disturbed by a prior County action. E %MAPLE Of 8 CUT and FILL SLOPE wens n� wxme wen.. eel RI CAII RW pn w kuiing be+rlox Flow LEVEL BUILDING SITES 8M CREATED OR STEEP SLOPES wv nL ...nom.. i� _�J -°- EXAMPLES OF RETAINING WALL DESIGNS TO AVOID AND PROMOTE Avo ;d Promote YN 11v RETAFING WALL HEIGHT W�- 17 -aJ. Uy ■■ 10 .—p you m Lon Ini � / _d N'�_+_�Im �1■ u..: :i w W B ,4&d4ou 1u -IRatlpe 6U, I: C. M � M X L pmnil NdKm"wm*wl Exempt Activities Potentially Include -Road Construction. * - Sanitary Water and Sanitary Sewer facilities. - Stormwater facilities. - Public Utilities. * -The establishment of the first dwelling on previously approved residential lots. * - Public and Private recreation, such as trails. - Accessory uses on previously developed residential lots such as, gardens, sheds, driveways, decks and patios. - Expansion of an existing structure. Next Steps in the Zoning Text Amendment Process - Receive Citizen Advisory Council input. - Hold an Open House with notification being mailed to affected property owners in the development areas -Hold a work session with the Planning Commission to review public input received at the Open House and to determine if the proposed zoning text amendment is ready to be scheduled for public hearings or if additional work is required. Goals for this Evening (1) Receive feedback on the concept of "Managed" and "Preserved" areas instead of the existing one size fits all requirements. (2) Receive feedback on criteria used to designate areas as either "Managed" or "Preserved ". (3) Receive feedback on the maps prepared by County Staff showing "Managed" and "Preserved" areas. (4) Discuss development standards for "Managed" critical slopes; and (5) Discuss exempt activities. Draft — 7/10/13 3.1 Definitions Critical slopes: Slopes other than managed slopes or preserved slopes of twenty -five (25) percent or greater as determined by reference to either current topographic mapping available from the county or a more accurate field survey certified by a professional surveyor or engineer. Slopes of twenty -five (25) percent or greater created as the result of lawfully approved development shall not be considered critical slopes. (Added 7- 11 -12) Managed Slopes: The term Managed Slopes means any slope shown as a Managed Slope on a map adopted by the Albemarle County Board of Supervisors. Preserved Slopes: The term Preserved Slopes means any slope shown as a Preserved Slope on a map adopted by the Albemarle County Board of Supervisors. Critical Slopes Overlay District 30.7.1 Purpose and Intent • The purpose of this section is to establish as an overlay district property within the development areas of Albemarle County which have steep slopes and for which additional development design care and consideration must be given, prior to the development occurring. The intent of this district is also to establish development design standards, which will protect the integrity of the steep slope areas, resulting in development, which will enhance and preserve the character and beauty of the steep slope areas of the county. This section recognizes that not all steep slopes have the same limitations for development. Therefore, two categories of steep slopes are established; Preserved and Managed. Preserved slopes are those slopes that have characteristics that warrant their preservation by the prohibition of disturbance except in the limited circumstances set out in this ordinance. The characteristics of Preserved slopes are: • The slopes are a contiguous area of 10,000 square feet or more or a close grouping of slopes less than 10,000 square feet. • The slopes are part of a system of slopes associated with a water feature. • The slopes are part of a hillside system. • The slopes are identified as a resource in the Open Space Plan. • The slopes are identified as a resource in the Comprehensive Plan. • The slopes may be of significant value to the Entrance Corridor District. • The slopes are shown to be preserved by a prior County action. Proposed Overlay District Regulations • Managed Slopes are those where development may occur provided that design standards are met to mitigate the impacts caused by the disturbance of the slopes. The characteristics of Managed Slopes are:The contiguous area of critical slopes is limited or fragmented. • The slopes are not associated with a water feature. • The slopes are not natural. • The slopes have been significantly disturbed prior to June 1. 2012. • The slopes are located within previously approved single family residential lots. • The slopes are shown to be disturbed by a prior Countv action. 30.7.2 Permitted Uses A. Managed Slopes 1. Uses permitted by right in the underlying zoning district shall be permitted by right in the Critical Slopes overlay district provided that the disturbance to establish such use complies with the County Code and the design standards contained in 30.7.3. 2. Any lot or parcel of record which was lawfully a lot of record on DATE OF ADOPTION may establish the first single - family detached dwelling unit on such lot or parcel; provided the parcel does not contain adequate land area outside of managed slopes for the location of such structure. For the purposes of this section, the term "lawfully a lot of record" shall also apply to any lot shown on a subdivision plat approved prior to DATE OF ADOPTION, provided such plat has not expired. Any disturbance to establish the first single- family detached dwelling shall comply with the design standards contained in 30.7.3. B. Preserved Slopes 1. The following uses are permitted by right on Preserved Slopes provided that the disturbance complies with the County Code and the design standards contained in ,�n_TR. a. Any structure which was lawfully in existence prior to DATE OF ADOPTION maybe expanded, enlarged, extended, modified and /or reconstructed. For the purposes of this section, the term "lawfully in existence" shall also apply to any structure for which a site development plan was approved or a building permit was issued prior to DATE OF ADOPTION, provided such plan or permit has not expired. b. Any lot or parcel of record which was lawfully a lot of record on DATE OF ADOPTION may establish the first single - family detached dwelling unit on such lot or parcel; provided the parcel does not contain adequate land area in Proposed Overlay District Regulations outside of preserved slopes for the location of such structure. For the purposes of this section, the term "lawfully a lot of record" shall also apply to any lot shown on a subdivision plat approved prior to DATE OF ADOPTION, provided such plat has not expired. c. Public facilities necessary to allow the use of the parcel provided that any of the following factors apply: 1. The disturbance avoids impacts on other protected resources such as stream buffers or floodplain. 2. The alignment is consistent with facilities included in the Comprehensive Plan. 3. The disturbance is necessary to provide interconnection required by the County Code or the regulations of other agencies. 4. Literal enforcement of the provision will result in unnecessary hardship. 5. The exceptional narrowness, shallowness, size or shape of a specific piece of property at the time of the effective date of this ordinance, the strict application of the terms of this ordinance would effectively prohibit or unreasonably restrict the use of the property. d. Public or Private pedestrian and cycling trails. e. Accessory uses to dwellings lawfully in existence prior to DATE OF AIInDTInAI 2. The following uses shall be permitted by special use permit. a. Private facilities such as accesways, utility lines and appurtenances and stormwater management facilities necessary to allow the use of the parcel 30.7.3 Design Standards a. The maximum height for a single retaining wall, measured from grade to grade, shall be 6 feet. When the overall retained height would exceed 6 feet, the retaining wall shall be broken into multiple stepped walls. Proposed Overlay District Regulations A minimum horizontal distance of 3 feet shall be maintained between each individual wall in the stepped wall system, and shall be landscaped with screening shrubs planted on 10 foot centers. 2. Retainine walls may be incorporated into the desien of a structure so that th become part of the structure. Retaining walls incorporated into the design of a structure shall not be subject to limitations in height. b. Cuts and fills shall be rounded off to eliminate sharp angles at the top, bottom and side of regraded slopes. c. The toe of the fill slope shall not be located within 10 feet horizontally of the top of an existing or proposed cut slope. d. Tops and bottoms of cut and fill slopes shall be set back from existing and proposed property lines a distance at least equal to the lesser of three feet plus 1/5 of the height of the cut or fill, or 10 feet. e. Cut and fill slopes shall not be steeper than 2:1 (fifty (50) percent). Where the slope is to be mowed, the slope shall be no steeper than 3:1 (thirty three (33) percent. f. Reverse slope benches or diversion shall be provided whenever the vertical interval (height) of any 2:1 (fifty (50) percent) slope exceeds 20 feet; for 3:1 (thirty three (33) percent) slope it shall be increased to 30 feet and for 4:1 (twenty- five (25) percent) to 40 feet. Benches shall be located to divide the slope face as equally as possible and shall convey the water to a stable outlet. 1. Benches shall be a minimum of six feet wide to provide. 2. Benches shall be designed with a reverse slope of 6:1 (seventeen (17) percent) or flatter to the toe of the upper slope and with a minimum of one foot in depth. Bench gradient to the outlet shall be between 2 percent and 3 percent, unless accompanied by appropriate design and computations. 3. The flow length within a bench shall not exceed 800 feet unless accompanied by appropriate design and computations. g. Surface water shall be diverted from the face of all cut and /or fill slopes by the use of diversions, ditches and swales or conveyed downslope by the use of a designed structure. The face of the slope shall not be subject to any concentrated flows of surface water such as from natural drainage ways, graded swales, downspouts, etc. h. Subsurface drainage shall be provided where deemed necessary by the County Engineer to intercept seepage that would otherwise adversely affect slope stability or create excessively wet site conditions. 30.7.6 Amendment of Critical Slopes Overlay District Proposed Overlay District Regulations 1. The delineation of the critical slopes overlay district may be revised, amended and modified by the board of supervisors after application is made by the owner in accord with the provisions of section 33 provided that the application includes field run topography prepared by a licensed engineer, surveyor or landscape architect indicating that the area does not include slopes of 25% or greater. or, 2. The delineation of the critical slopes overlay district may be revised, amended and modified by the board of supervisors after application is made by the owner in accord with the provisions of section 33. 35.1 FEES. Each applicant shall pay the following applicable fees, provided that neither the county nor the county school board shall be required to pay any fee if it is the applicant: b. Zoning map amendments: 1. Less than 50 acres; application and first resubmission: $2500.00 2. Less than 50 acres; each additional resubmission: $1250.00 3. 50 acres or greater; application and first resubmission: $3500.00 4. 50 acres or greater; each additional resubmission: $1750.00 5. Deferral of scheduled public hearing at applicant's request: $180.00 6. No fee shall be reauired for applications submitted in accord with section 30.7.6(a). j. Required notice: 1. Preparing and mailing or delivering up to fifty (50) notices: $200.00, except for uses under sections 5.1.47 and 5.2A, or applications submitted in accord with section 30.7.6(a), for which there shall be no fee. 2. Preparing and mailing or delivering, per notice more than fifty (50): $1.00 plus the actual cost of first class postage. No fee shall be required for applications submitted in accord with section 30.7.6(a) 3. Published notice: cost based on a cost quote from the publisher, except for farmers' markets under section 35.1(c)(7) and (8) or applications submitted in accord with section 30.7.6(a) for which there shall be no fee. Proposed Overlay District Regulations ATTACHMENT B I" Critical Slopes Roundtable 12/9/09 Topics - Redefine Critical slopes as 45% not 25% - 25% is ideal for walkout basements - Give consideration for slopes between 25% and 45% based on erosion hazard. - Slopes near streams could receive regulation. - Treat slopes differently based on proximity to streams. - Treat slopes differently based on area. (10 sq. ft. of contiguous slopes is different than 10,000 sq. ft. of contiguous slopes.) - Are critical slope regulations necessary at all? - Albemarle County Regulations are different than other jurisdictions. - Use Open Space as reference for regulation. - Maps should be updated so that slopes are easily identifiable. - Field survey should always trump County GIS. - Clarify waiver criteria. Criteria should be less subjective. - Reduce post construction standards in handbooks. - Establish cost /benefit analysis for phasing projects. (Time project may remain open) - Standards should be technical only. - Aesthetics should be addressed by means other than Critical Slopes regulations. - Phasing mass grading plan makes phasing of project more difficult. - Protect slopes based on environmental and aesthetic standards and all other slopes may be disturbed. - Establish post development standards. - Existing Erosion and Sediment Control standards address disturbance. No additional regulation needed to address construction period. Post development standards could include length /height of slopes and retaining walls. Design standards should allow for a purely administrative process. Update Open Space Plan. - The size of the critical slopes should determine the level of regulation. - If stream quality can be improved by disturbing slopes then the disturbance should be permitted. - Goals and regulations for critical slopes should match. - Realize that critical slopes have to be impacted to get from one place to another. - Adopt separate critical slope regulations for wireless facilities. - Establish minimum area before slopes are considered critical. (10,000 square feet was suggested). - Location standard for regulation and not minimum size standard. - Past problem has been no connection between waiver and changes or conditions requested by Planning Commission. - To promote development in Development Areas remove all critical slope regulations except those slopes associated with streams buffers. - Evaluate past waivers to see if consistent issues exist. - Base Critical Slopes regulations on science. - Clarify definitions of criteria — created slopes, aesthetic value. - Clarify who makes determination of value slopes and evaluates request against review criteria. ATTACHMENT B Insure appeal route exists. - Define what a stream is in the development areas. - Any regulation should result in an improved outcome. WPO plan and E &S plans are required. Current process does not achieve anything. Regulations should distinguish between created and natural slopes. Critical Slopes waivers should be administrative. - By -right projects are turned into something else solely due to presence of critical slopes. This results in a significant investment in time. - Process and criteria are too complicated. 2nd Critical Slopes Roundtable 2/17/10 Topics - Develop a decision tree (standards) for waivers. - More defined administrative checklist - Conditions should be tied to waivers. So that review is beneficial. (Mitigation) - If an intermittent stream is placed in a culvert does a system still exist? - Waiver process encourages developments to minimize impacts. - Fact that majority of requests are granted does not mean process isn't beneficial - Add predictability /consistency to decision making. - Investigate additional areas for administrative flexibility - Don't completely sacrifice critical slopes in development areas - Establish threshold - water resources are primary threshold - Critical slopes associated with water systems are not waiver able. - Use a system concept. Contiguous areas are a system. - Criteria. Demonstrate that biological quality is better post development than pre - development. - Off site /on site off sets at greater than 1:1 - Criteria. Geology, restabilization possibilities. - Criteria. Areas to keep as non - waiver able such as recreation and open space. - Criteria. Green infrastructure. - Criterion should make outcome of waiver easily predictable. - Identify types of slopes totally taken off table. - Make one type of process easier and another type impossible. - Don't establish process that pushes development into RA because process is difficult in DA. - Redefine Critical Slopes based on soils and geology. - Rank slopes on value. - Don't base on slope. Small areas of steep slopes and larger areas of shallower slopes to be protected. - Buffers on maps don't equal good buffers on the ground. - Establish a baseline /snapshot on existing slopes. ATTACHMENT B Calculate how much area would be given to development if any changes are adopted. Tie waiver to improvement in water quality. - Re- evaluate exemptions. Particularly sewer lines. Tallahassee, fla — canopy tree streets Utilize streamwatch data - Establish post development standards. Problem of allowing development access to areas where development wouldn't occur without waiver. Base waiver on existing and post development water quality. Area outside of determined area should be open for development but only with detailed set of conditions establishing post development standards. - Standards for critical slopes waivers should be easier in DA than RA. - RA critical slopes are a system themselves. RA waivers should have many more considerations. - Recognize that competing goals exist in DA but not in RA. - Make development in RA more difficult than in DA. - Expand evaluation of critical slopes to include RA. Recognize that DA and RA are very different. RA has rare and special features. - Best development is redevelopment. Way to mitigate critical slope impacts is redevelopment. - Investigate trading nonpoint source credits. - Consider original intent of critical slopes. - Require impact statement by developer with County field verification. - Provide incentives to protect critical slopes. All critical slopes should be protected without possibility of waiver. Consider things both within the Comp plan and outside of Comp Plan. - Evaluate waiver process to verify that all steps in the process are necessary and not just bureaucratic steps. Make sure environment is still protected by quantitative, output oriented standards Steep slopes modulate density of construction and provide visual interest. While vacancy rates are high focus on redevelopment. Return to exec summary ATTACHMENT C Comprehensive Plan Statements about Critical Slopes Reasons to protect steep slopes (slopes of 25% or greater) in the Development Area, as indicated in the Comprehensive Plan: 1. To prevent siltation, sedimentation, and extensive erosion (p. 107) 2. To prevent landslides or sloughing of soil (p. 107) 3. To prevent excessive stormwater runoff and surface water and groundwater pollution that can occur from excessive stormwater runoff (p. 107) 4. To retain environmental systems of streams and woods (p. 108) 5. For an aesthetic resulting from the relationship of buildings to landforms and vegetation (p. 142) 6. For good urban design which respects the existing natural and cultural landscape and creates new urban open spaces (p. 142) 7. To retain wooded areas that are valued by residents and that provide shade, windbreaks, buffers, and visual breaks (p. 142) 8. To protect viewsheds that are valued by residents (p. 106 of NM — actual quote: Viewshed impacts should be considered when designing buildings on steep slopes). 9. To protect and enhance riparian corridors. Stream buffer widths should be adjusted based on the presence of wetlands, floodplains, adjacent critical slopes and /or erodible slopes using guidance from the Open Space Plan and other watershed considerations. (p. 37 Water Resources) Which slopes should be protected? 1. Large contiguous areas of critical slopes especially along stream valleys, where the slopes overlay with other significant resources. (Open Space Plan) 2. Slopes that are identified for preservation to enhance the quality of life in the Development Areas (p. 106 of NM) Actual quote: The County recognizes that not all steep slopes should be preserved from development in the Development Areas. Significant features identified for preservation in the Open Space Plan, as well as other environmentally sensitive areas, should be mapped during the Master Planning process. As described in Section 4 (of the NM) the first map created should identify particular areas of steep slopes, forested land, streams and stream valleys to be preserved to enhance the quality of life in the Development Areas. ATTACHMENT C Return to exec summary Attachment D Background on Critical Slopes and Management Strategies After mapping the critical slope resources of the development areas staff considered what the typical impacts are to critical slopes. Slopes are cut and filled to achieve a level surface for roads, parking and buildings. Below are diagrams providing a basic example of what occurs during the development of critical slopes. EXAMPLE Of a CUT a Fed FILL SLOPE 1a3tt is I grade ur ne nomia or Uu OF fo r Fill - � f - W ROW SoIrt EJLa k`rF'g "- inn How LEVEL B U ILIDINO SITES are CREATED orb TEE P SLOPES WT 1.k Y 21 1' -- -- 1 - _ � r rli OPTP" ice. ARi M As can be seen from the above diagrams the creation of a flat area can result in the creation of slopes steeper than previously existed. Based on staff research and the comments made at the Roundtables staff opinion is that the resulting character of development on critical slopes is important to the community and consistent with best planning practices. FILL SLOPES BLENDED WITH NATURAL STEEP HILLSIDE Rw" edge* of td W 4�+w Rotl nd too Arlo aodo m ni I'm m owns w[hiMreLF#s�6e 15YWtlinWJnFtlNrsiCRbfi w Shin natural eenbDLI . f7 aril DL4iGRAM II -Z: LANDFORM GRADED SLOPES cLivea • , v.nwn.. �� oair.■ ■urn.N , • , f r' emu. - - - - - - -• ti r y r - rl Rn, mw Lop and or oh" - � t� - r �� s y• l . L4ntliOnn �+ - - r - --~_--- To•E� -1 L.naf- I!-d,g P.. EXAMPLES of PREFERREWNoT PREFERRED GRADING TECHNIQUES - Rounded transiion - ;Varied slope Preferred #founded tramItion - 1+�reeEl �oqe Preferred RDsmct rraturai Preferred - Abrupt transition - Uniform slope Not Preferred - Arirupt transiton Unrform slope Grade large tree terrace Ay -i t 5rwrui icd "d Preferred EXAMPLES OF RETAINING WALL DESIGNS TO AVOID AND PROMOTE Avoid -promote To achieve the desired grading character the use of development standards should be implemented. By using development standards the disturbance of "Managed" critical slopes can be processed administratively. Developers will know what standards to use and can incorporate those standards into their designing and planning processes at the beginning of the project layout. Neither the developer nor the citizens of the County will have to wonder if the development of a certain area will be permitted or what it will look like. Some areas will not be permitted to be developed while others may be developed with known standards. Some types of development standards that could be developed include: (These standards were taken directly from other jurisdictions and the specific requirements may not be appropriate for Albemarle County. The standards are provided to give an example of the types of regulations that might be used to achieve the desired character of development.) - Finished slopes of all cuts and fills shall not exceed thirty three (33) percent, unless the applicant can demonstrate that steeper slopes can be stabilized and maintained adequately to the satisfaction of (Municipality) - No retaining wall shall exceed the height prescribed in Section — (Section of Municipal Ordinance regulating fences and walls) of the Zoning Ordinance, and there shall be at least 10 feet between stepped retaining walls. All retaining walls require a certification by a professional engineer that the wall was constructed in accordance with approved plans and applicable building codes. - No trees with a diameter at breast height (DBH) of eight (8) inches or more shall be removed from steep slope areas unless in accord with Section _ (Section of municipal zoning ordinance regulating forestry). - No tree or other vegetation determined to be of specimen quality as determined by a registered landscape architect or which generally falls within the parameters of the following table shall be removed from steep slope areas. The examples of specimen trees included in the following table are intended to provide guidelines and examples of what constitutes a specimen tree and are not considered all inclusive for the purpose of defining a specimen tree. Examples OfPotentLal Specimen Trees uficies min.size H] s ies Min, iu Species Size (DBH} Apple 24" Locust 30" Sassafras 20.. Ash 32" maple 32'" Sycamore 36" $tech 32" Oak 32" Tulip Poplar 36" IV Osage Qnwge 24" Watout 30" Elm 3U" Pine 30 -- Hickary 32" Hemlock 3U "' Spruce 30 -- - Tops and bottoms of cut and fill slopes shall be set back from existing and proposed property lines a distance at least equal to the lesser of three feet plus 1/5 of the height of the cut or fill or 10 feet. - Tops and bottoms of cut and fill slopes shall be set back from structures a distance that will ensure the safety of the structure in the event of the collapse of the cut or fill slopes; generally, such distance will be considered to be six feet plus 1/5 the height of the cut or fill but need not exceed 10 feet. Nevertheless, a structure may be built on a slope or at the toe of a slope if it is designed to retain the slope and to withstand the forces exerted on it by the retained slope. - A minimum horizontal distance of 3 feet shall be maintained between each individual wall in the stepped wall system, and shall be landscaped. - Retaining walls could be incorporated into the design of the structure so that they become part of the structure. - Gravity retaining walls could be used, regardless of the height, provided that landscaping and irrigation is installed in the face of the wall. - The transition between manufactured slopes and natural topography should be blended to avoid harsh angular lines. Landscaping on manufactured slopes adjacent to natural topography should be similar to the vegetation on the natural slopes. (With guidance from the recently approved database of native plant species). - The maximum height for a single retaining wall, measured from grade to grade, shall be 10 feet. When the overall retained height would exceed 10 feet, the retaining wall shall be broken into multiple stepped walls, with no individual wall height exceeding 6 feet. RETAINING WALL HEIGHT Max V - L.n41■ DLl '■ 14' -n, Atipim GLIB COM. I9d 1�11� 6C '�w mwz d' - Dimis 0 U 10' - MaIL016 0U. I� Caro. Ind ■■ I■M■F gg � MIN $hula ydll Muff 6 &Lapped well - Cut and fill slopes that are to be stabilized with grasses shall not be steeper than 2:1. When slopes exceed 2:1, special design and stabilization consideration are required and shall be adequately shown on the plans. (Note: Where the slope is to be mowed, the slope should be no steeper than 3:1, although 4:1 is preferred because of safety factors related to mowing steep slopes.) - Reverse slope benches or diversion shall be provided whenever the vertical interval (height) of any 2:1 slope exceeds 20 feet; for 3:1 slope it shall be increased to 30 feet and for 4:1 to 40 feet. Benches shall be located to divide the slope face as equally as possible and shall convey the water to a stable outlet. Soils, seeps, rock outcrops, etc., shall also be taken into consideration when designing benches. A. Benches shall be a minimum of six feet wide to provide for ease of maintenance. B. Benches shall be designed with a reverse slope of 6:1 or flatter to the toe of the upper slope and with a minimum of one foot in depth. Bench gradient to the outlet shall be between 2 percent and 3 percent, unless accompanied by appropriate design and computations. C. The flow length within a bench shall not exceed 800 feet unless accompanied by appropriate design and computations; see Standard and Specifications for Diversion on page 5B.1 - Surface water shall be diverted from the face of all cut and /or fill slopes by the use of diversions, ditches and swales or conveyed downslope by the use of a designed structure, except where: A. The face of the slope is or shall be stabilized and the face of all graded slopes shall be protected from surface runoff until they are stabilized. B. The face of the slope shall not be subject to any concentrated flows of surface water such as from natural drainage ways, graded swales, downspouts, etc. C. The face of the slope will be protected by special erosion control materials, sod, gravel, riprap, or other stabilization method. - Subsurface drainage shall be provided where necessary to intercept seepage that would otherwise adversely affect slope stability or create excessively wet site conditions. - Slopes shall not be created so close to property lines as to endanger adjoining properties without adequately protecting such properties against sedimentation, erosion, slippage, settlement, subsidence, or other related damages. It is recognized that certain activities should be permitted even in "Protected" areas. These activities potentially include: - Road Construction. - Sanitary Water and Sanitary Sewer facilities. - Stormwater facilities. - Public Utilities. - Public and Private recreation, such as trails. - Accessory uses on previously developed residential lots such as, gardens, sheds, driveways, decks and patios. - Expansion of an existing structure. - The establishment of the first dwelling on previously approved residential lots. These are examples of the general types of activities that may be permitted in "Protected" areas. Standards for determining when alternatives exist should be developed. Return to exec summary