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HomeMy WebLinkAbout03.0 BOCC Staff Report 06.17.1996BOCC 6/17/96 PROJECT INFORMATION AND STAFF COMMENTS REQUEST: Preliminary Plan review for the Levitt Subdivision. APPLICANT: Thomas Levitt PLANNER: Land Design Partnership ENGINEER: High Country Engineering, Inc. Zancanella & Associates LOCATION: A tract of land located in portions of Sections 28 & 29, T7S, R87W of the 6th P.M.; located in Missouri Heights, approximately 0.5 mile west of the Eagle County line in southeastern Garfield County. SITE DATA: 79.455 Acres WATER: Central well SEWER: Individual sewage disposal systems ACCESS: Fender Lane (Eagle County), County Road 102 (Garfield County); easements EXISTING ZONING: A/R/RD ADJACENT ZONING: A/R/RD I. RELATIONSHIP TO THE COMPREHENSIVE PLAN The proposed subdivision lies within District F - Rural Areas/Severe Environmental Constraints and District B - Subdivisions/Rural Serviceable Areas 0.5 to 1 Mile Radius; Minor Environmental Constraints, as designated by the Garfield County Comprehensive Plan's Management Districts Map (1984 Plan). The subject property is located in the Medium Density Residential (6 to 9 acres/dwelling unit) and Low Density Residential (10+ acres/dwelling unit) Proposed Land Use Districts, as designated by the Garfield County Comprehensive Plan for Study Area I (1995 Plan). II. DESCRIPTION OF THF ROPO AL. A. Site Description: The property is located on the slopes and crest of a mesa on the north side of the Roaring Fork Valley, in an area known as Missouri Heights. The property can be thought of as two (2) different physiographic provinces. The first province, consisting chiefly of the southern half and the western sixth (1/6) of the property can be described as very steep, where slopes are in excess of 40%, with some slopes in excess of 60%. The second province, where the homesites are proposed to be located, consists of the mesa crest, where slopes are typically quite gentle. The buildable portion of the property slopes gently east to west, from approximately 7040 feet to 6900 feet, an average slope of 6.0%. The vegetation varies from pinion juniper dominating the steeper slopes, to sage and annual grasses existing on the mesa top. See vicinity map attached on page B. Proposal: The applicant proposes to subdivide the 79.455 acre tract into 13 parcels, ranging in size from 4.0 acres to 9.1 acres, with a gross density of 6.1 acres/dwelling unit. Two (2) lots within the proposed subdivision would be allowed accessory dwelling units and three (3) lots would be allowed up to four (4) head of livestock. The individual lots are proposed to be served by a shared, central well system with 120,000 gallons of storage and individual sewage disposal systems are proposed for waste water treatment. An exaggerated cul-de-sac is planned to access the thirteen (13) individual lots and provide open space to the residents. See sketch map attached on page C. Adjacent Land Uses: The adjacent land uses are predominantly residential, with some larger parcels in the vicinity. Additionally, some agricultural land uses exist in the vicinity. TEL REVIEW AGENCY/PUBLIC COMMENTS A. Colorado Department of Health: Did not note any violations or discrepancies with state guidelines regarding ISDS or drinking water. States that a project of five (5) or more acres total (disturbed) area will need a storm water construction permit. See letter, page B. Roaring Fork School District RE -1: Requests impact fees, or land in lieu of impact fees, for the subdivision. See letter, pages . Staff notes that, typically, the county collects a school impact fee of $200.00, per lot, prior to final approval. C. Colorado State Forest Service: Conducted a site inspection on March 22, 1996, and concluded that the proposed homes be located 100 feet from the edge of the slope. This recommendation was based on National Fire Protection Standards with the intent of protecting homes from convective and radiant heat originating from a wildfire below a structure. The site analysis further recommended the implementation of defensible space around all structures. Discussions with the local fire district concluded with the opinion that the road system is sufficient for wildfire control purposes. See letter, page D. Carbondale & Rural Fire Protection District: Commented that access throughout the subdivision appears to be adequate for fire apparatus; noted some concern that the end fire hydrant, supplied from the water storage tank would be able to supply 1000 gallons per minute, as proposed; the developer would be required to pay impact fees of $235, per lot ($3055 total), due prior to recording a final plat. See letter, page E. Colorado Geological Survey: Commented that the steep slopes are an important constraint to development of the property as they are subject to the potential for downslope movement; noted that particular care should be taken when siting individual sewage disposal systems and the siting of surface and sub -surface drainage systems and recommends a minimum setback of 25 feet from the topographical break. Additionally, the Survey notes its concern for the underlying Eagle Valley Evaporite Formation, which is susceptible to dissolution, possibly creating ground failure and sink holes. Recommends that each building site be investigated by a shallow geophysical survey to better characterize the Eagle Valley Formation. See letter, pages F. Division of Water Resources: Indicates that the Basalt Water Conservancy District contracts would be sufficient to prevent injury to decreed water rights; recommends that no approval occur until the developer has District contracts for the proposed wells and has obtained valid permits for the proposed uses; states that, with sufficient storage, it appears that the wells can supply adequately the proposed uses and that the long-term adequacy of any groundwater source may be subject to fluctuations due to hydrologic and climatic trends. See letter, pages G. Adjacent Landowner: The attorney for Sirous Saghatoleslami, an adjacent landowner, has commented indicating opposition to the placement of the water storage tank as being unnecessarily conspicuous. See letter, page IV. MAJOR ISSUES AND CONCERNS A. Soils: There are three (3) predominant soil types on-site, each with their own characteristics affecting development potential and the siting of building envelopes and ISD systems. The three (3) soil types and their chief characteristics are as follows: #43 - Forelle/Brownsto Complex: This soil comprises the top of the ridge, where the homesites are proposed. The soil is generally deep and well -drained, found on slopes between 6 and 12%. Constraints to building site development potential varies from moderate to severe due to slope and the potential for cutbanks to cave in the Brownsto unit. Constraints to location of ISDS facilities is considered moderate to severe because of slope and the Forelle unit is further hindered by slow percolation. #55 - Gypsum land-Gypsiorthids Complex: This soil complex formed from parent material that was high in gypsum content (Eagle Valley Evaporite) and constitutes the lower slopes of the property. This part of the site is not slated for development but, due to its limitations, should be considered as it does underlie the soils comprising the buildable portions of the property. Constraints to building site development and placement of ISD systems are considered severe, chiefly because of depth to bedrock and slope. The Eagle Valley Evaporite, which underlies the property and forms the characteristic tan and brown slopes on the north side of the Roaring Fork Valley, is susceptible to erosion and subsidence as it is prone to dissolution. Staff suggests that special consideration is needed to determine the severity of this problem in and on this property. Hepworth-Pawlak Geotechnical has evaluated the letter submitted by the Colorado Geological Survey (CGS) and the severity of the threat caused by the underlying Eagle Valley Evaporite and, in summary, discounts the recommendation made by the CGS as to requiring subsurface exploration. See letter, pages #106 - Tridell/Brownsto Complex: This soil complex occupies the upper slopes of the property and tends to be deep and well to excessively -well drained. Constraints to building site development are considered to be severe due to slope and the tendency for cutbanks to cave. Constraints to location of 1SD systems are considered severe due to slope and that the soil tends to be a poor filter. The geotechnical study suggests that, underlying the soils on the property, basalt flows between 50 and 200 feet thick may be encountered and that sound basalt will be encountered at typical basement depths. Basalt is an igneous rock, formed when basaltic lava was extruded at the surface and cooled into solid rock. Basalt is a very dense rock and, unless it is cut by a system of joints, it tends to have very little permeability. In areas where there is a joint system, these joints can have positive and negative effects on the hydraulic characteristics of the underlying water table and, in a worst case scenario, "piping" of effluent water can occur, which could have negative effects on groundwater. Staff recommends that all septic systems be engineered, based on site-specific ISDS locations, at the time of building permit application. Water: The proposal specifies the use of a shared well to supply water to the subdivision. At this time, two (2) wells have been drilled and only one (1) well has been pump -tested. The pump test was conducted on March 19, 1996, at a pumping rate of 20 GPM, for a 24-hour period. The pump -tested well was completed to a depth of 320 feet and the static water level was found to be approximately 255 feet below the surface, an available drawdown of 65 feet. As stated, the well was pump -tested for 24 hours with drawdown for the testing period calculated to be 1.9 feet, showing a continuous drawdown with no stabilization over the time of the pump test. Upon completion of the pump test, recharge characteristics were also gathered for a 24 hour time period, indicating the well did not recover at a greater rate than it was pumped, which suggests that water pumped during the test was from storage in the underlying aquifer and the current recharge rate of the aquifer is less than the pump test flow. See pump test letter dated April 2, pages . Measurements taken on March 26, indicated the well recovered to a level that was approximately four (4) inches higher than the initial, static water level, indicating that there was no permanent depression in the aquifer. See supplemental pump test letter, pages . It is the opinion of the engineers conducting the test that there is a substantial reservoir to supply water to the subdivision and, further, that the well is capable of supplying the subdivision's needs. The engineers recommend that a homeowner's association take prudent steps in designating a well monitoring program to manage the water resource and further state that "Annual water volumes pumped from the aquifer will need to be matched or remain less than the annual recharge to the aquifer system." This information, although difficult to assess, should be taken very seriously in an effort to effectively manage the water resource, especially as the Missouri Heights area develops. Staff would suggest this recommendation be specifically described within the homeowner's covenants. The original, hydrogeologic study conducted by Minion Hydrologic and bound within the preliminary plan submittal analyzed existing water data from well completion reports of wells drilled in the area, as well as the site specific geology of the general area of this proposed subdivision. Although it is staffs opinion that this study is relevant, it did not include or evaluate an actual pump test; therefore, staff would tend to rely more on the actual information presented in the pump test as to the adequacy of the water supply. The engineers have submitted revised calculations indicating an annual water diversion requirement of 12.70 acre-feet, of which 3.98 acre-feet would be consumed. At time of buildout of the subdivision, instantaneous demand for water would be greater than can be provided by the well alone, requiring the necessity for on-site storage, as well as water for fire -fighting purposes. The applicant proposes the installation of a 120,000 gallon water storage tank to meet these water demands. The water service line is proposed to be an eight (8) inch, non -looped line that would be required to have either a fire hydrant or a blow -off valve at its terminus. The engineers further recommend the addition of another well to provide mechanical reliability to the system and constructed at 50% build -out of the subdivision. An additional well has been drilled; however, it has not been pump -tested and staff cannot comment on its ability to adequately perform this function. Both the water storage tank and the well would be located off of the subdivision site and would require easements across the adjacent parcels. These easements must be sufficient to allow access and maintenance of the facilities and staff recommends minimum easements of 20 feet, for the water supply line, wellhead and storage tank. Staff notes that an adjacent property owner has objected to the proposed location and construction of the tank as being too conspicuous. The letter is included in the review/comment section of this report, page Legal Water Supply: The applicant has recently been issued a water allotment contract from the Basalt Water Conservancy District for 14.9 acre feet of water, per year. The engineers have calculated that annual diversions of groundwater would total approximately 12.7 acre feet. Therefore, it appears the water allotment contract should be sufficient to prevent injury to decreed water rights. See Basalt contract, pages Water Quality: A water quality analysis of inorganic chemicals and volatile organic chemicals was conducted on water samples from the pump -tested well, with the results concluding that all tested parameters were within mandatory, state standards. See water quality letter, page This water information has been developed for a total of 23 individual residential units and 12 livestock units, which includes eight (8) units that would not be constructed as a part of this proposal, but are "reserved" by the Levitt Family Trust, which owns the land upon which property the well and storage tank would be located. In staffs interpretation, the additional eight (8) [residential] units should be considered as a second phase and staff recommends that any approval of the Levitt Subdivision proposal shall not be construed as approval of a later subdivision proposal or phase. C. Access/Roads: Access to the property is proposed to be along easements from County Road 102, across adjacent property, to the applicant's tract. Access and maintenance easements are in place for the access across the adjacent property north and east of the subject tract; however, at this time, no agreement regarding the maintenance of Harmony Lane has been approved by all affected parties. It appears that Harmony Lane is a public road that is privately maintained by the current users of the road, who request that the applicant contribute, on a pro -rata basis, to the continued maintenance of the road. The applicant has agreed to upgrade that portion of Harmony Lane between Wind River Road and CR 102 to a consistent platform width and a chip/seal surface, to be largely consistent with Garfield County Secondary Access standards. See letter and Road Maintenance Agreement, pages The Planning Commission recommended conditional approval of the Preliminary Plan pursuant to the applicant having, in place, a signed agreement for the maintenance of Harmony Lane at the time of the Board's hearing. If this signed agreement has been completed, it has not been submitted for review. The thirteen (13) lots that would be created by this subdivision would require a Rural Access road standard throughout the subdivision, which includes a right-of-way of 50 feet, 11 foot travel lanes, six (6) foot shoulders and either a gravel or chip/seal surface. This internal road would be accessed via off-site roads known as Whitecioud Road and Wind River Road, which provide access to Harmony Lane and eventually CR 102/Fender Lane. At the intersection of Harmony Lane and CR 102, Harmony Lane would provide access to approximately 26 lots. There appears to be no accepted method to mitigate the impacts to the existing roads, as it appears Garfield County does not have the authority to require the applicant to upgrade the affected, off-site roads. However, the applicant has offered to improve Harmony Lane to a standard largely consistent with Rural Access standards. See letter pages . Although this provision may be difficult to enforce, staff sees the proposal as a proactive approach in mitigating certain road impacts and suggests it be a condition of approval. The Preliminary Plan submittal indicates the shoulders of the roadway within the subdivision are proposed to be two (2) feet in width, which may be approved in mountainous areas. The Planning Commission, with a finding that the subdivision is within mountainous terrain, approved the two (2) foot shoulders. The length of the road is significantly longer than the 600 feet normally allowed for a cul-de-sac design (approx. 3000 feet); however, longer cul-de-sacs may be allowed if it can be proven that fire protection and emergency egress and access is provided as part of the longer design. Access to lots 1, 2 and 3 would be along a secondary road that would be required to be built to Semi -Primitive standards with a 40 foot right-of-way, two (2) 8 foot travel lanes, and two (2) foot shoulders. According to the County Subdivision Regulations, all roads should be dedicated to the public; however, repair, maintenance and snow removal is the responsibility of the Homeowners Association. D. Fire Protection: The applicant proposes the installation of a 120,000 gallon water storage tank that would be capable of supplying 1000 gallons of water for a two (2) hour period, for fire -fighting purposes. A total of three (3) fire hydrants are planned, spaced approximately 800 feet apart and plumbed into an eight (8) inch service line. It would appear that this amount of water, in conjunction with adequate roads should be sufficient in the event of a fire. There was originally some speculation by the Fire District that the 1000 GPM could be supplied at the terminal fire hydrant, as originally proposed. The engineers have suggested the upgrade from a six (6) inch water line to an (8) inch line to provide the 1000 GPM flows. As part of its review, the District requests $235.00, per lot ($3055 total), be paid to the District in impact fees, prior to recording a final plat. In its review letter, the Colorado State Forest Service, (CSFS) using recommendations made by the National Fire Protection Association (NFPA) and published in the 1991 edition of Protection of Life and Property From Wildfire, recommends a minimum, slope setback of 100 feet. Currently, the developer proposes a minimum slope setback, for all lots located along the slope, of 50 feet. Staffhas discussed the CSFS recommendations to better understand the criteria used to determine the necessity of the specified 100 foot setback and was referred to the following diagram (excerpted from the above noted publication): Staffhas attempted to determine the specific analysis used by the CSFS to make this setback recommendation; however, at this time, there appears to be no mathematical explanation for the recommendation. The recommendation may seem extreme and perhaps arbitrary; however, considering that the CSFS would be regarded as the expert in this domain, staff will defer to its recommended setback of 100 feet. F. Lot Size: All lots conform to the two (2) acre minimum lot size as stipulated by the A/R/RD zone district. However, the lots on the southern and western portions of the property consist chiefly of steep slopes (>40%), which restrains the buildable portions of these lots. Subdivision Regulations specify certain requirements regarding setbacks, slope, and minimum size of building envelopes. Given the proposed building envelopes, it appears all lots can meet applicable setback and slope requirements; however, if the Commission enforces the CSFS recommended setback of 100 feet, then the affected lots may need to be re -drafted. It should be noted that, gross estimates indicate that approximately 40 acres of the entire 79.5 acre tract are of less than 40% slope. Therefore, effective density of the 13 proposed lots would be approximately 3 acres per dwelling unit. G. Open Space Easements/Detention Pond: The proposal specifies deeding the open space to the residents of the subdivision; however, it appears that this open space land will actually be sold as portions of four (4) different lots. In fact, the Subdivision Application Form indicates a total of zero (0) acres within the development area be preserved as Public/Quasi-Public or Open Space/Common Area. The arrangement where the area within the cul-de-sac is deeded to the public would require that specific covenants be drafted to ensure unimpeded public access, and should further specify maintenance responsibilities. The open space would consist of approximately 0.5 acre of irrigated lawn area. A storm water detention pond is proposed for the western -most portion of the open space area, planned to straddle the property line between lots 9 and 10. The pond is designed to retain a volume of 5,063 cubic feet, the expected runoff volume from the 25 -year storm. Once the retention volume is exceeded by storm events of higher magnitude, the water is designed to drain directly from the overflow into the existing drainage on the western end of the property. Staff recommends this drainage be lined with an appropriate material (concrete; rip -rap; etc.) to ensure that no erosion occurs, which could possibly result in further down -cutting or slope instability within and along the drainage. This recommendation is supported within the Colorado Geological Survey letter. Additionally, it will be necessary to draft specific covenants regarding maintenance of the detention pond and attendant facilities. H. Aesthetics: Currently, no County regulations exist regarding setback requirements from ridges; therefore, adherence to CSFS recommendations would have two outcomes. First, this placement would help protect homes in the event of a fire moving up the ridge and, second, would decrease the visual impact caused by a line of homes constructed at or near the ridge, which could be quite visible from many points in the Roaring Fork valley. Compatibility with the Comprehensive Plan: Section 4:33 of the Subdivision Regulations requires review of a subdivision application based on compatibility with various planning criteria, including the Comprehensive Plan. The following section addresses the compatibility, or lack of compatibility, with the Plan. Agriculture: Housing: The subdivision is potentially compatible with agricultural land uses as the majority of adjacent land uses are residential. Existing, platted subdivision lots currently exist within a five mile radius of the proposed subdivision, with current build -out estimated at an average of 49%. Conventional zoning, not PUD, is being employed. There are no provisions for low and moderate income housing (stated) within the subdivision application information. The subdivision is situated away from incompatible, non-residential uses such as light industry and commercial centers. Recreation/Open Space: The proposed development includes provision for open space. Transportation: County regulations do not have any provision for off-site improvements to County roads. The applicant is limiting traffic to one intersection. Roadway design is targeting a specific, projected traffic load. Roadway design has been conducted in consideration for potential emergencies. Water and Sewer Service: It does appear that a legal, physical water supply exists. The development could not feasibly connect to any existing community water/sewer system. Soils on-site are constrained in their use for ISDS. Environment: There are slopes on the parcel which are in excess of 25%. Mitigation of erosion by development of the property is required. Mitigation of slope hazards may be necessary. V. SUGGESTED FINDINGS 1. That proper publication and public notice and posting were provided as required by law for the hearing before the Board of County Commissioners. 2. That the hearing before the Planning Commission was extensive and complete, that all pertinent facts, matters and issues were submitted and that all interested parties were heard at the hearing. 3. That the proposed subdivision of land is in general compliance with the recommendations set forth in the Comprehensive Plan for the unincorporated area of the County. 4. That the proposed subdivision of land conforms to the Garfield County Zoning Resolution. 5. That all data, surveys, analyses, studies, plans and designs as are required by the State of Colorado and Garfield County have been submitted and, in addition, have been found to meet all requirements of the Garfield County Subdivision Regulations. VI. RECOMMENDATION The Planning Commission, at its May 8, 1996 meeting, recommended APPROVAL of the application, pursuant to the following conditions: 1. That all representations of the applicant, either within the application or stated at the public hearings before the Planning Commission and the Board of County Commissioners shall be considered conditions of approval, unless stated otherwise by the Planning Commission and the Board of County Commissioners. 2. The Homeowner's Association shall be incorporated in accordance with Colorado Revised Statute requirements. 3. The applicant shall prepare and submit a Subdivision Improvements Agreement addressing all on-site improvements, prior to the submittal of a final plat. 4. The applicants shall submit improvement plans for all roads, bridges, utilities, fire protection, improvements, signage and drainage structures prior to the submittal of the final plat. 5. That all utilities shall be placed underground. 6. That all cut slopes created during construction shall be revegetated with native grasses, shrubs and trees with adequate weed control. All revegetation shall be in accordance with the applicant's revegetation plan. Revegetation and landscaping shall be included in the Subdivision Improvements Agreement. In addition, adequate security shall remain in place for a period of two (2) years to guarantee the survival of all plantings. That the applicant shall demonstrate that procedures are established for the maintenance of all roadways and bridges, including snow removal, through the Homeowner's Association. 8. That the applicant shall pay $200 per lot in School Impact Fees prior to the approval of the Final Plat. 9. That the following plat notes shall be included on the Final Plat: "The minimum defensible space distance shall be 30 feet on level terrain, plus appropriate modification to recognize the increased rate of fire spread at sloped sites. The methodology described in "Protection of Life and Property From Wildfire, 1991 Edition," (NFPA) shall be used to determine defensible space requirements for the required defensible space within building envelopes in areas exceeding five (5) percent grade, except that the slope setback shall be a minimum of 50 feet, for all lots. "Prior to issuance of a building permit, the owner of each lot shall prepare and submit a soils and foundation report and an I. S.D.S. design prepared and certified by a professional engineer. All improvements shall be constructed in accordance with such measures, which shall be a condition of the building permit." "Access to the Levitt Subdivision shall only be allowed from Harmony Lane and shall not be allowed from Sunset Lane." 10. The Basalt Water Conservancy District Allotment Contract and the water rights associated with the wells, together with well permits, shall be transferred by the developer to a homeowner's association which shall have the power and the duty to enforce compliance by lot owners with the terms and conditions of the water contract. 11. That the applicants shall prepare and submit protective covenants, articles of incorporation and other Homeowner's Association documents, including by-laws, will be submitted for review by the County Attorney prior to the approval of the Final Plat. 12. That the plat and covenants will provide that there will be no resubdivision of the lots. 13. Based upon the determination, by the Planning Commission, that the internal subdivision roadway is in mountainous terrain, all roadways shall be constructed in accordance with the design standards in effect at the time of submittal of the Final Plat, except that the roadway shoulders will be two (2) feet in width. 14. The Final Plat shall identify building sites that are in conformance with the recommendations of the geotechnical report conducted by Hepworth-Pawlak Geotechnical and be less than 40% slope. 15. That adequate easements for wells, waterlines and other attendant facilities and utilities shall be provided on the Final Plat. 16. That 10 foot front lot line easements, on each lot, shall be provided for utility purposes. 17. The applicant shall provide road signage in accordance with the Uniform Manual of Traffic Control. These should be included in the Subdivision Improvements Agreement. 18. Prior to the approval of the Final Plat, the applicant shall submit approved plans (by Colorado Department of Health) for the proposed community water system. 19. The restrictive covenants shall include the "Aspen Glen" provisions regarding lighting, fire places and dog restrictions and further mandate specific procedures for monitoring the water supply consistent with the recommendations made by the engineer and contained within the engineer's letters dated April 2, 1996 and April 29, 1996. 20. That the applicant will improve Harmony Lane, from Wind River Road to County Road 102, to Secondary Access standards including a chip/seal surface. This provision shall be contained within the Subdivision Improvements Agreement. 21. The construction of the overflow from the proposed detention pond will be done in a manner to affirmatively mitigate erosion that may be caused by the apparatus or anticipated water flows. 22. Approval of this subdivision Preliminary Plan does not construe approval for any later phases or associated developments on or off the subject property. 23. The applicant shall submit the appropriate impact fees directly to the Carbondale and Rural Fire Protection District and provide the Planning Department a copy of the receipt, prior to Final Plat approval. 24. That Accessory Dwelling Units shall only be allowed on lots 12 and 13 and livestock shall only be allowed on lots 11, 12 and 13. These provisions and limitations shall be stated within the protective covenants. 25. That the applicant shall agree upon and enter into a maintenance agreement, for maintenance of Harmony Lane, with the Harmony View Subdivision Homeowner's Association, prior to approval of the Preliminary Plan by the Board of County Commissioners.