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HomeMy WebLinkAbout3.0 PC Staff Report 09.14.2005Exhibits for Public Hearing held on September 14, 2005 #t r. Exhibit A Mail Receipts B Proof of Publication C Left Intentionally Blank D Garfield County Zoning Regulations of 1978, as amended E Garfield County Comprehensive Plan of 2000, as amended F Application G Staff Memorandum H Email from CDOT dated 6/23/05 , I Memorandum from the Road and Bridge Department dated 6/28/05 J Letter from the Colorado State Forest Service dated 6/24/05 K Letter from the Colorado Geologic Survey dated 6/23/05 L Letter from the Division of water resources dated 6/30/05 M Letter from Steve Anthony dated 7/7/05 N Letter from Christina Burke dated 7/24/05 0 Letter from Michael Gross dated 8/08/05 P Email memo from the Town of Silt dated 7/6/05 Q Letter from Dana Yerian dated 7/5/05 R Letter from Resource Engineering dated 7/11/05 S Memo from the County Environmental Health Manager dated September 6, 2005 3.3 i'GGoy4 L 5,14 s. 144 (/ - c . 4 4y,) 1- 1. Sht la -V) sy 3) Tom` )47-175,) 54 . d . ?coy, /2",.tie4 ( 2,6 X g-oa- - C i G 74.75-7 �. /- 3' n 6010..4441 1. rig ""' Arb S � " �► 3- f'-nd �~ 611 1444 4.4- 5 c. U) 14/4- 44k 3,- Po% A- 4 4 14e (v tAded ,mo 44 -� ?•ir-Lv� r - 5y)7J rtr e4.04 Pig 6giss ft ita co6i‘ 4/4- 5- 4414, ,J;(4/1 /ii --z-5-? t -A4-? /27 - id: i2).- 4 7 4-/, P o‘44.9 1 EXHIBIT I G PC 09/14/05 FJ PROJECT INFORMATION AND STAFF COMMENTS REQUEST Preliminary Plan review for Peach Valley Vistas Kelly Lyon Gamba & Associates East of Silt, North of I-70 at Davis Point 54.88 acres Central Water System ISDS CR 235 and Davis Point Road A/R/RD A/R/RD APPLICANT / OWNER REPRESENTATIVE LOCATION PROPERTY SIZE WATER SEWER ACCESS EXISTING ZONING SURROUNDING ZONING 1 I. GENERAL PROJECT INFORMATION A. General Property Description The subject property is located lh miles east of Silt just east and adjacent to Davis Point Road, north of I-70 and south of CR 214. The cre property consists primarily of gently sloping open cultivated hay fields on the northern half of the property and a small vineyard on the southern portion of the property. The Ware & Hines Ditch and the Lower Cactus Valley Ditch traverse the west and south portions of the property. The Ware and Hines Ditch which runs southward along the western lot line has made a significant cut into the lower portion of the property and eventually drains into the Colorado River. This cut has been graded and the ditch run-off has been more formally channeled through the lower portion of the property to a culvert under the Lower Valley Cactus Ditch and out to the Colorado River. The Lower Valley Cactus Ditch runs just inside the southern boundary of the property. Two wetland areas have been delineated on the lower -eastern portion of the property. Established vegetation of the property is relatively minimal but characterized by a few stands of large mature cottonwood trees on the southern portion of the nearer to the grape vineyard. B. Proposal The Applicant proposes to subdivide the 58.88 -acre property into twenty-five (25) lots; twenty-four of those lots are approximately 1.00 acres in size leaving the balance of the property in Lot 25 containing 18.5 acres using the County's cluster subdivision process. The Applicant has proposed a Yield Plan showing 24 lots and a Cluster Plan showing 25 lots. Domestic water is to be provided from a central water supply system that includes 2 wells and an 80,000 gallon storage tank with a water treatment system. Waste water will handled with Individual Sewage Treatment Systems (ISTS) on each lot. Irrigation water will be provided to all the lots via shares from the property owners ditch shares in the ware & Hines Ditch. Access to each of the lots will be provided by in internal looped cul- de-sac road within a 50 -foot right-of-way from Davis Point Road (CR 235). Significant site characteristics of the property including the Ware & Hines Ditch "drainage cut", two wetland areas, and natural storm water drainages have been placed into either "Drainage and Soil Conservation Easements" or "Wetlands Preservation and Drainage Conveyance Easements /Areas of No Disturbance." Both ditches (Ware & Hines and Lower Valley Cactus Ditch) are located within their own easements. Both 2 wells are located within maintenance and access easements and the water storage tank for the water system has been located in an easement with access provided to the Applicant on an adjacent property to the west to take advantage of higher elevation. C. Background As you may recall, on July 13th, 2004, the Applicant presented the sketch plan to the Planning Commission where the Commission determined that the property / design was well suited to the "cluster" development option offered by the County's Subdivision regulations. At that meeting, the Applicant stated they intended to submit an official "yield plan" and "cluster plan" under the County' s cluster regulations which is the subject of the present proposal. II. REFERRAL AGENCIES / DEPARTMENTS Staff referred the application to the following State agencies and / or County departments for their review and comment. Comments received are briefly mentioned below or are more comprehensively incorporated within the appropriate section of this memorandum. a. Town of Silt: Provided comments related to ISDS, trails, affordable housing, and out-of-town taps for both water and sewer. (Exhibit P) b. County Road and Bridge Department: The Applicant shall deed a 30 -foot ROW from the center line of CR 235 and CR 214 along the entire length of the subdivision to the County. All fences, structures, trees and brush that encumber this ROW will be removed back to the new ROW by the developer prior to final plat; a driveway access permit will issued with conditions specific to the driveway access will be issued upon final approval by the BOCC; and a stop sign will be installed at the driveway access entrance to CR 235. (Exhibit I) c. Burning Mountain Fire Protection District: No Comments received. d. RE -2 School District: No Comments received. e. Colorado State Forest Service: Wildfire hazard is low to moderate and can be mitigated with defensible space measures (Exhibit J) f. Colorado Department of Transportation: An access permit would be required at County Road 235/ US 6 intersection (Exhibit H) g. Colorado Division of Wildlife: No Comments received. h. Colorado Department of Public Health and Environment: No Comments received. i. Colorado Division of Water Resources: No material injury (Exhibit L). j. Colorado Geologic Survey: Recommends against approval of this subdivision until the concerns outlined by CGS have been addressed (Exhibit K) k. Garfield County Vegetation Manager: No comments received. 1. Resource Engineering: Provided comments regarding rockfall, septic constraints, soil issues, water quality, and traffic issues. See Exhibit (R) m. County Environmental Health Manager: Provided comments regarding the proposed ISDS plan (See Exhibit S). 3 III. GENERAL RELATIONSHIP TO THE COMPREHENSIVE PLAN The property is located within Study Area 2 which designates the property as "Outlying Residential" on the proposed land use designation map. This designation indicates residential development is appropriate for this property at a density of 1 unit per 2 acres which is also consistent with the underlying zoning of ARRD. As a result, the residential use and density are all consistent with and conform to the Comprehensive Plan land use map. However, due to the soil constraints on the property, the proposed ISDS for the project does not appear to be compatible with or conform to the Goals, Objectives, or Policies of the Comprehensive Plan regarding waste water disposal found in Section 7: Water & Sewer Services of the Plan. Namely, the proposal has not demonstrated how 1) the proliferation of ASDS on individual sites has been carefully reviewed in terms of soil constraints and drainage characteristics of each site and 2) to ensure that the provision of legal, adequate, dependable, cost effective and environmentally sound sewer and water services for new development. IV. APPLICABLE ZONING REGULATIONS IN ARRD ZONE DISTRICT The following is an analysis of the proposed development with the required zoning regulations of the ARRD zone district. A. Proposed Uses The Applicant proposes single-family residential development on all of the 25 lots which is contemplated as a "use by right" in the A/R/RD zone district and is therefore consistent with the underlying zone district. For other uses, the Applicant should consult Section 3.02 of the Zoning Resolution. B. Common Dimensional Requirements ➢ Lot Size / Slope: The Applicant proposes the 58.88 -acre property be subdivided into 25 developable lots that comply with the 2 -acre minimum lot size. However, several of the lots are encumbered by raw water ditches, wetlands, storm water drainages, and well easements. The Applicant should be aware that every lot will need to have a building area ("building envelope") of at least 1 contiguous acre with slopes less than 40% pursuant to Section 5.04.02(2) of the Zoning Resolution. ➢ Maximum Lot Coverage: Fifteen percent (15%) ➢ Minimum Setback: o Front yard: (a) arterial streets: seventy-five (75) feet from street centerline or fifty (50) feet from front lot line, whichever is greater; (b) 4 local streets: fifty (50) feet from street centerline or twenty-five (25) feet from front lot line, whichever is greater; o Rear yard: Twenty-five (25) feet from rear lot line; o Side yard: Ten (10) feet from side lot line, or one-half (1/2) the height of the principal building, whichever is greater. Maximum Height of Buildings: Twenty-five (25) feet C. Supplementary Lot Area Regulations Generally speaking, Section 5.04.02(2) requires that all lots must have at least a 1 - acre building envelope that contains slopes less than 40%. Smaller envelopes may be approved by the Board so long as slope is adequately addressed. Note, while the minimum lot size in the ARRD zone district is 2 acres, one of the benefits offered to developers for developing under the "cluster subdivision regulations" is that lots may be as small as 1 acre. In light of this, Staff finds that the proposed envelopes which are slightly less than 1 -acre, have met the requirements related to slope and recommend the Board approved the smaller envelopes. V. YIELD PLAN & CLUSTER PLAN REVIEW As required in the Cluster Subdivision Regulation (pursuant to Section 4:11 of the Subdivision Regulations) the following section provides an analysis of the proposed Yield Plan which is a site plan intended to demonstrate the realistic number of residential lots possible based on the County's conventional development parameters in the ARRD zone district. This exercise is critical to determine the number of "bonus lots" that the Planning Commission can award to the developer to be incorporated in the Cluster Plan. The Yield Plan analysis represents the first of a two-step process required by the Cluster Subdivision Regulation. A. Proposed Yield Plan The Applicant proposes a Yield Plan (included as Sheet Y-1 of the submittal) which shows a site plan that includes twenty-four lots that are approximately 2 -acres in size. This 5 plan also includes a central access road of the correct right-of-way width to serve the lots. The plan also preserves identified wetlands and drainage course that have been placed in protective easements throughout the site plan. During the sketch plan review, Staff required the Applicant to demonstrate the practical feasibility of the internal road alignment to accommodate a gully crossing on the southwest portion of the property. The Applicant provided additional information on this issue which ultimately indicated that it is possible from both an engineering perspective and a cost analysis perspective as indicated by the road cost estimate and a proposed road profile. Basically, while the cut and fill required for the crossing will be much more expensive, the benefit of reaching an additional lot will generate funds to cover the additional cost. Based on a review of the applicable zoning and subdivision regulations as well as a site visit, Staff finds the proposed Yield Plan is possible and could reasonably yield 24 residential lots. B. Proposed Cluster Plan The Applicant submitted a Cluster Plan that shows a site plan based on a minimum lot size of one (1) acre. This plan includes twenty-four (24) 1 -acre lots and a twenty-fifth lot containing 18.5 acres. The twenty-four (24) 1 - acre lots have been clustered together on the southern half of the property that preserves an agricultural open space area of otherwise developable land in Lot 25. This plan must specifically address the following criteria: (1) A calculation of total developable land, based on land area contained in legal and allowable lots as defined, in a proposed Yield analysis. The acreage of total developable land in the Yield Plan is 52.86 acres. (2) A calculation of developable land reserved for greenbelt or common open space, as a percentage of total developable land. The acreage of total developable land (as a percentage) reserved for the agricultural open space in the Yield Plan is 6 approximately 35%. C. Bonus Lots Based on the 24 possible lots in the Yield Plan and due to the percentage of otherwise developable land being placed in agricultural open space, the Applicant requests approval for one additional lot based on the calculation below: (1) For preserving otherwise developable lands, as determined in the Clustering Option as defined by Garfield County, placed in a Common Open Space or Greenbelt designation amounting to twenty-five percent (25%) or more of the otherwise developable tract or parcel of land being subdivided, development applicants shall be entitled to one additional developable lot, or one additional developable lot for every sixteen (16) or more otherwise developable lots, whichever is greater, or, if the next threshold is met: Staff finds the Cluster Plan qualifies for 1 bonus lot for having placed at least 25% in agricultural open space. D. Cluster Plan Development Components A proposed Cluster Plan is required to include a narrative description directly relating to the preserved open space which includes the following: (1) A description of the land to be included in common open space or greenbelt. Staff Response The Applicant proposes to designate 18.51 acres as a greenbelt which is currently used for hay production. It will remain in an agricultural use as producing hay fields. The Applicant also proposes a 6.55 -acre portion of the property (the southwest corner) as common open space. (2) Ownership and proposed management of the common open space or greenbelt. Staff Response The greenbelt lot (Lot 25) will be deed restricted to prohibit further development and be held in private ownership while the common open space parcel will be conveyed to the Homeowners Association. (3) A weed control and erosion management strategy for the common open space or greenbelt. Staff Response The' Applicant has inventoried weeds (Canada Thistle, Russian Knapweed, and Cheatgrass) on the property as well as put together a management plan that addresses weed control on all of the lots including the greenbelt lot (Lot 25) and the common open space parcel. Weed management on the common open space parcel will be delegated to the Homeowners Association and weed management on the greenbelt lot will be privately managed according to the provisions in the protective covenants. 7 (4) Intended uses allowed in the common open space or greenbelt, and amenities and structures to be placed there, if any. Staff Response The Applicant proposes to designate Lot 25 (containing 18.51 acres) as a greenbelt which is currently used for hay production. It will remain in an agricultural use as good producing hay fields. The Applicant also proposes a 6.55 -acre portion of the property (the southwest corner) as common open space. VI. APPLICABLE SUBDIVISION REGULATIONS The following section addresses common subdivision components that are required as part of the Preliminary Plan for the Cluster Plan. A. Water Regarding potable domestic water, the Applicant proposes to provide water to all the lots in the development by a central water supply system. Physically, this system includes the provision of water from two existing and permitted wells that will be treated and pumped up to a 80,000 gallon water storage tank on an adjacent property which will then will gravity feed water to all the lots. The County typically uses a water usage calculation of 100 gallons per person per day for a household of 3.5 persons or a total of 350 gallons a day per household. These two wells, augmented by an approved West Divide Water Conservancy Contract, may produce up to a maximum of 13.665 acre feet per year. A helpful calculation is provided here for legal water usage: ➢ 13.665 acre feet / yr = 4,452,712.92 gallons/ yr (or 494 gallons per lot per day) The proposed 80,000 gallon water tank is proposed to be located within an existing easement on the adjacent property to the west at an elevation sufficient to provide pressure for a gravity feed system. Staff suggests this easement be transferred to the Homeowners Association. The Applicant shall be required to obtain a "road cut / bore permit" from the County Road and Bridge Department to bring the lines across CR 235 (Davis Point Road). This permit would accommodate water lines sending treated water from the subdivision up to the tank and also lines carrying the stored water back to the lots within the subdivision. Additionally, the water lines will also cross the Ware and Hines Ditch which will require approval from that ditch company for the crossing. Water Quality The water quality in this area of the County tends to be of a poorer quality. Resource Engineering stated that "water quality of the wells indicates that several parameters exceed primary and secondary drinking water standards." Based on quality testing, the Applicant proposes a water treatment system consisting if a packed tower aeration unit and a GAC unit to mitigate radon and toluene to levels below the Maximum Containment Levels (MCL). The water system report also suggests that water softeners and Reverse Osmosis (R) systems be installed in each house. Should the Board approve this proposal, Staff suggests a plat be placed on the final plat requiring all lots shall have RO systems be installed as part of the building permit process. 8 Because this water system will serve at least 15 residences or 25 persons, it is considered to be a Community Water Supply by Colorado Department of Public Health and Environment (CDPHE) which requires approval of the system. Should the Board approve this subdivision; Staff recommends this approval by CDPHE be considered a condition of approval. Irrigation Water For irrigation water, the Applicant indicated that no irrigation water would be provided from the domestic system. The Applicant owns shares in the Ware & Hines Ditch which he intends to deed to the Homeowners Association. In this way, individual lot owners would be entitled to shares / portion of shares from the Ware & Hines Ditch and distributed by the Association. Physically, water storage of the irrigation water would be either from a pond located on Lot 25 or individual tanks and booster pumps on each lot. This low-pressure raw water irrigation system will be constructed by the Applicant as part of the subdivision improvements secured in the SIA. The plans for this raw water distribution system are located on Sheet C4 of the plan set. No pond was illustrated on the plan set delivered to the County and was not reviewed by the Division of Water Resources regarding water rights required to fill the pond. The Division of Water Resources stated the proposed domestic water supply system will not cause material injury to decreed water rights; however, they could not comment on the physical or legal adequacy of the irrigation system stating the Applicant wito provide additional information to the Division of Water Resources regarding the proposed raw water irrigation system. As a result, the proposal has not demonstrated that is can provide irrigation water which is required by Section 9:51 of the Subdivision regulations. B. Waste Disposal The Applicant proposes that each lot will install Individual Sewage Disposal Systems (ISDS) to handle waste water which has been illustrated in the ISDS Operation and Maintenance Plan submitted in the application (Appendix L). This plan is important to this development due to the fact that all but one of the lots is 1 -acre in size with some lots being further limited by constraints such as wells, wetlands, and ditches. The Plan contains a Conceptual ISDS Map which shows a 3,200 sq. ft. house foot print on each lot. The map also shows how typical ISDS can be accommodated on each lot with leach -fields, setbacks from wells, structures, property lines, etc. While it appears that this plan is consistent with the CDPHE's ISDS regulations enforced by the County, there are several significant issues related to extremely low permeability, high groundwater, loading, adequate space, cost, and practical feasibility of ISDS on such small lots which are provided here outlined by the County Environmental Health Manager (See Exhibit S): 1. The percolation test data on page 199 of the Preliminary Plan Report (Appendix L) indicates percolation rates of 240 minutes per inch (mpi), 240 mpi and 213 mpi recorded at three test holes spread across the subject property. These percolation test results are consistent with the soil boring logs found in Appendix F. According to the soils information contained in Appendix G, soil types 4, 29, 30 and 34, located on 18-19 of the proposed lots, are moderately to severely limited for urban uses. These limitations are based on moderate to low permeability and shrink/swell potential. Although this data may not be representative of each individual site, the location of the test holes along with the soil 9 survey information suggests that similar percolation test results could be expected across a large area of this subdivision. 2. In many ISDS design review programs across Colorado, the 240 mpi soils on this site would be considered unsuitable soils for ISDS at least on lots this size. I spoke to Andy Schwaller and he indicated that this issue is addressed in Garfield County by requiring an engineer's design for any parcel with such soils. Although this may not be the most appropriate solution to this issue, this requirement is consistent with the State ISDS Guidelines. 3. Soil boring data in Appendix F indicates the presence of bedrock and groundwater at 2 feet and 10 feet respectively in test holes 3 and 4. Both holes appear to be in the area of the proposed development. Again, the limited number of holes may not represent actual conditions across the entire development, .but these tests do indicate that additional lots could be limited or restricted by subsurface conditions. 4. The ISDS calculations included in Appendix L do not include the water -use appliance factor as required by the Garfield County Building Department (I confirmed this requirement with Andy S.). The Building Department requires an additional 60% factor be added to leach field area calculations to accommodate the use of garbage disposals and other water -use appliances used in typical residential developments. As such, the additional factor would increase a system with 240 mpi soils from 2789 to 4462 square feet, approximately 10% of a 1 -acre lot. Based on the proposed ISDS map, additional leach field area requirements could preclude a number of these systems from being built based solely on available area and mandatory setback requirements. 5. The information submitted regarding the use of Infiltrator Systems, Inc. chamber units for leach fields has several flaws. Required areas aside, the proposal calls for a 126 unit leach field with 9 rows of 14 units laid out in a bed configuration. The plan also calls for a total trench width of 3.42 feet created by separation between rows. The plan also indicates that each unit is 6 feet by 3 feet for a total square footage of 18 square feet per unit. The CDPHE Water Quality Control Division issued a letter several years ago giving Infiltrator Systems, Inc. only 15.5 square feet of open bottom area credit for a standard chamber unit (not the 20.5 feet indicated in the proposal). I confirmed with Andy S. that Garfield County uses this number. I also confirmed with Mr. Eric Berquist of Infiltrator Systems, Inc. that this number has not changed. Based on 15.5 square feet per unit, the minimum number of chambers required by state and local policy for the example provided and the square footages stated in #4 above would be 180 and 288 units respectively. Furthermore, the actual footprint of the Infiltrator chamber is 18.75 square feet so the associated excavation for these systems would be 3375 and 5400 square feet. Also, assuming these systems could fit on the properties, the cost for Infiltrator units (based on Gamba and Associates information) would increase from the suggested $3528.00 to $5040.00 or $8064.00. 6. It is reasonable to assume that individual systems in poor soils will inevitably be used (or abused) in a manner that may result in leach field failure. The limitations imposed on many of the lots, either by site features or yet to be determined building locations, may preclude a large number of these lots from installing a replacement leach field except in the original location. This situation could be extremely problematic due to existing soil limitations and soil saturation when failure occurs. 10 7. To avoid problems with mandatory separation to bedrock and groundwater requirements and to maintain the most optimum soil conditions to promote soil treatment of effluent, it is important to keep leach fields as shallow as possible and at a consistent depth. The ISDS Map included in the preliminary plat proposal shows that a number of leach fields, particularly those closest to Davis Point Road, will be installed in areas with an elevation change of 4-10 feet across the designated leach field area. According to the ISDS guidance on the Garfield County website, leach fields are typically installed at about 4 feet deep to take advantage of gravity flow from the tank to the leach field. As such, some of these fields may require up to 14 foot excavations in areas. This creates possible conflicts with the groundwater and bedrock separation requirements and is far from optimal in terms of promoting effluent treatment in the soil. 8. Although it is not generally a consideration of the platting of a subdivision, installation of leach fields in such difficult soils can be a formidable challenge. Once these soils are disturbed, what structural characteristics that may have existed are, for the most part, no longer existent. Furthermore, if the soils are wet or subjected to vehicular traffic, substantial smearing and/or compaction will take place thereby reducing the already marginal permeability. Because the proposed leach fields would require such large excavations, it may be difficult to excavate without driving equipment into the excavations. Serious consideration should be given at this stage and must be given by the individual system designers and installers as to the location and configuration of the leach field along with the necessary space to operate equipment. As a result, the County Environmental Health Manager proposed the following recommendations: A. More percolation tests and profile hole inspections should be done prior to preliminary plat submittal to get a better handle on soil conditions of each lot. Should soil conditions be relatively consistent as currently described, then consideration should be given to alternative system design, pretreatment of wastewater before discharge, use of open space for absorption area, clustering systems, increasing lot sizes, etc. B. Consideration should be given to require that an appropriate area be reserved on each platted lot for leach field replacement. Prohibitions for use of these areas should include construction of buildings, animal corrals or pens, vehicular traffic and anything else that may result in soils compaction or changing of original soil characteristics. Some sort of recorded documentation on the deeds to the property should include these restrictions. C. Initial and any subsequent site grading should avoid all areas where leach fields are planned to maintain original grades and soil conditions. D. If this subdivision is approved, a detailed, specific ISDS management plan should be required of the applicant and subsequent homeowners to assure that these systems are systematically and properly inspected and maintained on a regular basis. Further, the HP Geotech soils report indicates that soils in the area have slow percolation rates. As a result, they state that percolation rates that fall outside the 5 to 60 minute per inch shall 11 require engineered systems. This could be handled as a plat note and requirement of building permit when the actual ISDS location is known. Should the Board approve the subdivision, Staff suggests this be considered as a condition of approval. Resource Engineering also reviewed the wastewater plan in Exhibit R which also stated that the percolation rates are very slow. Further due to the shallow ground water and slow percolation rates, a plat note should be added that states that all ISDS systems shall be designed by a registered professional engineer. C. Roads /Access The access to the subdivision will come from a main entrance off of CR 235 which is located approximately 1,000 feet south of the intersection of CR 214 and CR 235. An internal public road is proposed to provide access to each of the 25 lots. This road is configured in a looped design with a short cul-de-sac spur to the south. Using the TTT Trip Generation manual, 25 residential lots will generate approximately 239.68 trips at 9.57 trips per dwelling which requires that all internal roads be designed to the "secondary road" standard pursuant to Section 9:35 of the Subdivision Regulations. This road type requires a 50 -foot right-of-way, two 11 -foot driving lanes, 6 -foot shoulder widths, 6 -foot ditch widths, and a chip seal or gravel driving surface. The cul-de-sac is less that 600 linear feet and complies with the required standard. It appears the proposed internal roads have been designed to this standard. This internal road and cul-de-sac will also be required to be dedicated to the public but maintained by the Homeowners Association and memorialized on the final plat as a plat note. It should be noted, the road at the main entrance, will cross the Ware and Hines Ditch. This crossing will need to be adequately engineered and will need to be approved by the Ware and Hines Ditch Company. County Road & Bridge Comments (Exhibit I) The Garfield County Road & Bridge Dept. has no objection to this subdivision with the following requests: 1) That the Applicant provides a 30 -foot ROW from the center line of CR 235 and CR 214 along the entire length of the subdivision will be deeded to Garfield County. All fences, structures, trees and brush that encumber this ROW will be removed back to the new ROW at the Applicant's expense prior to final plat; 2) The Applicant obtain a driveway access permit with conditions specific to the driveway access will be issued upon final approval by the BOCC; and 3) The Applicant shall install a stop sign at the driveway access entrance to CR 235. The sign and installation will be as required in the MUTCD (Manual on Uniform Traffic Control Devices). Traffic Generation & the CDOT State Highway Access Code The 25 residences will generate approximately 240 trips. The trips counted at the intersection of 6&24 coming down CR 235 in the summer of 2002 were 307. As a result, this development will cause a 78% increase in the trips coming down CR 235 to its intersection with 6&24. This is a significant issue for the County because the CDOT State Highway Access Code requires 12 intersection improvements when 20% or greater increases in traffic volumes occur onto state roads at the cost to the County. As a matter of background, the State Highway Access Code Section 2.6(6) Changes in Land Use and Access Use, contains the following language: Vehicular use and operation of local roads where they connect to (access) a state highway is the responsibility of the appropriate local authority. The local authority should maintain such state highway access locations in conformance with the Code to the extent feasible and practicable within statutory and public funding limitations. The local authority may fund any necessary improvements by obtaining contributions from the primary users of the access or as off-site subdivision improvements necessary for the public safety pursuant to sections 30-28-133 and 133.1, C.R.S., and sections 31-23-201 to 227, C.R.S., or other available public funds and local requirements. CDOT reviewed the proposal and provided the following comments (Exhibit H): "The main access would be Garfield County Road 235. County Road 235 does access onto US 6. It appears this site will increase traffic by more than 20 percent on CR 235 intersection, therefore, an access permit would be required at County Road 235/ US 6 intersection. The County has the choice to be the permittee / applicant or have the developer be the permittee for the access permit." In a verbal conversation with CDOT, they indicated that they envision significant improvements to this intersection due to the lack of sight distance to the west because of Davis Point. At the drafting of this memorandum, CDOT did not make any specific determinations as to the extent of specific improvements. Note, the Town of Silt as well as a variety of neighbors to this property cite this intersection as being severely problematic. Based on this, the Applicant has not demonstrated how this permit will or can be obtained and therefore has not demonstrated how they have dealt with their off-site road impacts. D. Floodplain Issues / Drainage The property is not located in a regulated floodplain. The western portion of the southern half of the property contains steep slopes that will, once developed, impact the historic and direction of drainage on and off of the property. This is specifically related to a significant gully located on the southwestern portion of the property which is the result of run-off released from the Ware & Hines Ditch. This tail -water has been focused into a water course that enters a 24" culvert that runs underneath Lower Cactus Valley Ditch, Highway 6&24, then out to the Colorado River. The Applicant has recently (within the last two years) re -graded and re-contoured this gully to better accommodate the water course to deal with significant erosion and sediment control problems. Gamba & Associated prepared a drainage plan that concludes the post -development run-off will not exceed historic run-off except in two sub -basins. The Applicant has proposed two drainage ponds which are identified on Sheet 3 of the Drainage Plan which show Pond 1 located on the southern portion of Lots 11 and 12 and Pond 2 and the southern portion of Lots 14 and 15. Both ponds are to be improved with outlet structures. The development plan proposes a storm sewer (Sheet C6 of the plan set) that indicates how storm -water run-off is conveyed via 24" culverts from the drainage flow from the internal road to the drainage ponds. 13 In addition, the Applicant proposes an 800 foot long north — south drainage swale / berm located on the far eastern property and a 650 foot long east to west drainage swale / berm located along the southern edge of Lot 25. Both of these swales are intended to protect specific lots in a 100 -year event as described in the drainage report. All of the proposed swales and detention ponds are located within described drainage easements on the preliminary plan. The Colorado Geologic Survey commented on drainage (Exhibit K) stating the following: The wetland area in the east -central part of the property appears to be a spring and is not recharged from surface flow. On the Yield Plan (sheet No. Y1) there are 40 foot wide Drainage Easements proceeding in a southerly direction from the wetlands area. These drainage easements are not shown on the Preliminary Final Plat (sheet No. P2). There are building envelopes platted in the middle of the drainage easements in lots 10 and 11 as shown on sheet No. 1. The preliminary plat should show these drainage easements. Building envelopes should avoid drainage easement areas. E. Fire Protection The property is located in the Burning Mountain Fire Protection District. As mentioned earlier, the development is proposed with a central water supply system with an 80,000 gallon water tank. The water plan layout proposes an 8" main located within the internal road profile that will also connect to five fire hydrants located at approximately 400-500 feet increments along the road with a sixth hydrant located on the west side of Lot 25 adjacent to Davis Point Road approximately 300 feet north of the main entrance to the subdivision. The Colorado State Forest Service visited the site and indicated (Exhibit J) that the property maintains a fire hazard of low to moderate. Wildfire hazards can be mitigated with defensible space clearing and thinning and use firewise construction when feasible. In addition, the grass and weeds must be dealt with to reduce the accumulation of 1 -hour fuels which are fuels that are 1/4 inch or less in diameter and respond quickly to changes in their environment. This can be mitigated by regular mowing / re -seeding to reduce the intensity or possibility of a grass fire. F. Wildlife The Application contains two maps showing mapped wildlife areas on the property (Appendix J). Specifically, the property is located within Mule Deer Resident Population and Sever Winter Range as well as being located within Elk Winter Range and Winter Concentration Range. The Application was referred to the Division of Wildlife however no comments were received. G. Soils / Geology / Radiation The Applicant submitted soils information in the context of a HP Geotech report which indicates that soils on the property vary with regard to suitability for home site development. However, the report identified rockfall hazards at the base of Davis Point Mesa and steep slope hazards along the ravine that cuts through the southwestern portion of the property carrying the tail water from the Ware and Hines Ditch. It appears that Lots 1, 2 and 19 are located in the rockfall hazard zone identified by the CTL report which requires mitigation. The CTL report indicates that the ravine and the Ware and Hines Ditch actually provide effective rockfall mitigation. However, the report further explains that "if the water in the ravine and the ditch was to be piped and the ravine and ditch filled in, the rockfall hazard boundaries would change and additional mitigation would be required such as impact barriers and/ or catchment 14 structures. If development will be in rockfall hazard areas then a more detailed rockfall hazard evaluation will be needed to develop design level mitigation recommendations." In addition, the slopes of the ravine should be backfilled or roadways and structures should be set back from the top of the ravine's sides a horizontal distance equal to at least the vertical height of the sides. The Applicant has not addressed mitigation of the identified hazard. Section 5.16.03 of the Zoning resolution provides Guidelines for Development in Rock fall Areas. Decrease of a rock fall hazard to an acceptable level may be an acceptable mitigation technique if supported by qualified technical evidence. Methods may involve, among others: (1) Stabilization of rocks by bolting gunite application (cementing), outright removal of unstable rocks (scaling), cribbing or installation of retaining walls; (2) Slowing or diverting the moving rocks by rock fences, screening, channeling, and dams or by concrete barriers or covered galleries; or (3) Installation of physical barriers against rock impact around vulnerable structures More specifically, soils limitations in the area include some limited shrink -swell potential, low strength, slow permeability, some slope issues, depth to bedrock, exposed bedrock, slumping and creeping, and stoney soils. The CTL report specifically makes the following conclusions: 1. We did not observe any geologic conditions or geologic hazards that would preclude development of this site for the intended single family residential use. An area of potential rockfall hazard and potentially unstable slopes along ravine banks will need to be avoided or mitigation will be needed. The subsoil conditions are generally favorable for the proposed residential development. 2. Our exploratory borings penetrated a 1 to 2 feet thick layer of organic, sandy clay "topsoil" above silty to sandy clays. In our TH-1 the clays were underlain by claystone bedrock at a depth of 21 feet. In ourTH-3 the topsoil was underlain by sandstone to a depth of 20 feet. The sandstone may be bedrock or could be a large colluvial block from rockfall from Davis Point Mesa above the site to the west. Free ground water was found in our exploratory borings TH-1, TH-2 and TH- 4 at depths varying from 8 to 18 feet deep during our field investigation. 3. In general, we judge the native, silty to sandy clays to vary from a low expansion potential to a high compression potential. We judge the sandstone to be non- compressible and non -expansive. 4. We anticipate spread footings placed on native soils will be the recommended foundation type on lots where non -expansive clays and sandstone bedrock are exposed at foundation elevations. Where footings will be supported by moderately to highly compressible clays, it may be recommended to sub -excavate below the bottom of footings and backfill the sub -excavation with densely compacted structural fill. Where expansive clays occur at foundation elevations, footings with a minimum deadload may be recommended. We recommend design level soils and foundation investigations on a 15 lot by lot basis to determine the appropriate foundation type for individual buildings and to develop design level criteria. 5. Preliminary data indicates concrete slabs -on -grade floors placed on the slightly compressible clays will perform satisfactorily if the soils below slabs are not wetted. Where moderately to highly compressible clays occur at floor sub -grade elevations we will likely recommend to remove and replace 1 to 2 feet of the clays below floor slabs with structural fill similar to that below footings. Where expansive clays occur below floor slabs, slabs can likely bear on 1 to 2 feet of structural fill or structurally supported floors with crawl spaces below may be recommended. 6. Control of surface drainage is important to the performance of foundations, interior and exterior slabs -on -grade and roadways and access drives. Surface drainage should be designed to provide rapid removal of surface runoff away from buildings and off of roads. Water should not be allowed to pond adjacent to buildings, roadways or access drives. Should the Board approve this proposal, Staff suggests that based on these limitations, that the following plat note be required to provide disclosure to the potential lot purchasers that foundations and septic systems will need to have site specific analysis and engineering. "Foundations and Individual Sewage Disposal Systems shall be engineered by a Professional Registered Engineer within the State of Colorado." The Colorado Geologic Survey reviewed the proposal and provided comments regarding erosion, rockfall, soils / subsurface, and a fill in their letter attached as Exhibit K and which comments are included here: 1. Rockfall. The Geologic Evaluation by CTL Thompson outlines an area of existing rockfall hazard in the southwest corner of the property. They also outline a larger area of rockfall hazard "...without the existing ditch or after filling ravines." Rockfall mitigation must accompany any building within these zones. A rockfall analysis model, such as CRSP, must be conducted before approval of building lots in the rockfall hazard zone in order to determine the impact pressures of probable rockfall in the area and to design mitigation. There are areas within the property that do not have rockfall hazard and it would be less costly to simply move the lots platted within the rockfall hazard area to safe areas. 2. Erosion. The loess in the southwest part of the property is conducive to piping, which is the removal of soluble or easily eroded layers beneath the ground surface by running water. There is evidence of piping at the ground surface adjacent to the drainage from the Ware and Hines ditch (noted as the ravine in the southwest part of the site by CTL Thompson). Piping was evident up to 70 feet from the edge of the ravine. The depth of the piping is undetermined and there is the potential for void spaces beneath the ground surface that are not evident from surface inspections. The area in the vicinity of Lots 16, 17 and 18 is conducive to piping and should be inspected by a geotechnical engineer before actual construction begins to insure that there are no voids that could undermine a foundation. If any void 16 spaces are encountered, then the Geotech engineer will need to determine if mitigation is possible in this area. In the Geologic Evaluation and Preliminary Geotechnical Investigation, CTL Thompson states, "Some areas along the side of the ravine exhibit evidence of "recent" or "active" instability." The banks along the side of the ravine are experiencing severe erosion. Setbacks from these banklmay ave to be up to T57Tfee 1 in order to avoid erosion problems due to piping. Setbacks that are large enough to avoid erosion hazards may not leave enough room on Lots 16-18 for building envelopes. I recommend against building in this area without mitigation. 3. Soils/Subsurface. Some of the soil units described in the NRCS Soil information report indicate that the soils are poorly suited to home site development. This is mostly due to the potential for swelling soils. Due to the low number (four) of exploratory borings for foundation analysis, site- specific geotechnical investigations are recommended to determine if any mitigation is necessary to mitigate against swelling soils. 4. Fill. There are areas in the east part of the property that have existing man-made fill according to the Geologic Evaluation and Preliminary Geotechnical Investigation by CTL Thompson, Inc. All fill must be removed and reworked into structural fill per standard geotechnical specifications prior to construction. In conclusion, the southern part of the property has more geologic hazards than the north part of the property, yet all the development is planned for the south part. There is ample room in the north part of the property for building lots that are free from most of the geologic hazards discussed in this letter. If the developer wishes to continue with thp") development of the southern portion of the property, then extensive mitigation will be necessary to mitigate the numerous geologic hazards. I recommend against approval of this subdivision until the concerns outlined in this letter are addressed. H. Vegetation The Applicant submitted a Vegetation Management Plan as part of preliminary plan that addresses weed management, topsoil disturbance issues, and revegetation of disturbed areas in the development of the site. Also, during the sketch plan review, Staff suggested that development of the property be sensitive to and try to preserve the mature cottonwoods on the property. The Applicant shall provide the following items for approval as part of the final plat submittal application to the Building and Planning Department: a. A weed management plan needs to be submitted to deal with the mapped and inventoried noxious weeds for the property. b. The Applicant shall provide a calculation of the amount of disturbed area (in acres) as a result of the installation of infrastructure with the final plat application so that an adequate revegetation security can be established in a form acceptable to the County Attorney's Office to ensure the revegetation of the disturbed area. This shall be incorporated in the Subdivision Improvements Agreement (SIA). 17 c. Provide a soil management plan that includes provisions for salvaging on-site topsoil, a timetable for eliminating topsoil or aggregate piles, and a plan that provides for soil cover if any disturbances or stockpiles will sit exposed for a period of 90 days or more. I. Easements There are a number of easements depicted throughout the property which are intended to delineate and protect areas for drainage, utility, access, wetlands, and well and appurtenant water system components. The Applicant will need to delineate, legally describe, and convey all easements shown on the plat to the Homeowners Association. This dedication needs to be in a form acceptable to the County Attorneys Office and transfer shall occur at the time of recording the final plat. Other easements shall include any access and maintenance easements that need to be provided from the two ditch companies that have ditches that run through the property including the Ware and Hines Ditch and the Lower Cactus Valley Ditch. Lastly, as mentioned above, the County Road and Bridge Department has requested the Applicant deed a 30 -foot from center line right-of-way along the property boundaries that front CR 235 and CR 214. This shall be shown on the final plat. J. Assessment / Fees The property is located in Traffic Study Area 6 which requires a $210 per ADT traffic impact fee be paid to the County. This will be figured at the time of final plat. The Applicant could expect to pay an approximate preliminary Traffic Impact Fee of $44,892.00 of which lh shall be paid at final plat and included as a component of the Subdivision Improvement Agreement (SIA). The development is also located in the RE -2 School District which requires a $200 per lot School Site Acquisition Fee for a total of $ 4,800.00 to be paid at final plat and included as a component of the Subdivision Improvement Agreement (SIA). VII. STAFF RECOMMENDATION In the initial review, Staff ultimately found that the project was possible with a very strong and lengthy set of conditions and therefore recommended approval. Based on a closer analysis and a new significant review conducted by the County Environmental Health Manager, Staff finds that there are simply too many significant issues that 1) either haven not been fully addressed, or 2) cannot be addressed with the present design. At this time, Staff cannot recommend approval of the proposal finding that while the affect of the project' s design results in clustering lots while preserving 18 acres for agricultural use, the property is ill-suited for such a proposal. Other designs could work, but the proposed design does not adequately address the significant number of site constraints identified on the property resulting in the right project in the wrong place. Staff recommends the Planning Commission recommend denial to the Board of County Commissioners for the Preliminary Plan for the Peach Valley Vistas Subdivision with the following findings: 1. That the hearing before the Planning Commission was extensive and complete; all pertinent facts, matters and issues were not submitted; and that all interested parties were heard at the 18 hearing. 2. That the application is not in compliance with the standards set forth in Section 4:00 of the Garfield County Zoning Resolution of 1978, as amended and standards set forth in Section 4.00 of the Garfield County Subdivision Regulations of 1984, as amended and more specifically included here: a. Domestic Water Quality (Requires significant treatment that should not be passed onto the lot purchasers.) b. Adequacy of Irrigation Water (Not proven to be physically or legally adequate and therefore does not satisfy Section 9:51of the Subdivision Regulations of 1984.) c. Rockfall Hazard (Inadequate analysis on mitigation of lots identified to be located rockfall hazard zones and therefore does not satisfy Section 5.16.03 of the Subdivision Regulations of 1984.) d. Steep / Unstable Slopes on Drainage Cut from Ware & Hines Ditch (Inadequate analysis on mitigation of lots identified to be located in close proximity to steep / unstable slopes and therefore does not satisfy Section 5.14.06 of the Subdivision Regulations of 1984.) e. Intersection of State Highway 6&24 and Davis Point Road (Inadequate demonstration of ability to obtain a proper state highway access permit and effectively mitigate off-site road impacts from the development.) f. Soil / Septic Constraints (Inadequate analysis demonstrating that ISDS is the most suitable method to dealing with wastewater on 1 -acre lots with issues related to extremely low permeability, system cost, system space needs, and groundwater loading and therefore does not satisfy Section 4:92(D) of the Subdivision Regulations of 1984.) 3. That the proposed preliminary plan is not in the best interest of the health, safety, morals, convenience, order, prosperity and welfare of the citizens of Garfield County. 19 • • Fred Jarman From: Roussin, Daniel[Daniel.Roussin@DOT.STATE.CO.US] Sent: Thursday, June 23, 2005 8:53 AM To: Fred Jarman Cc: Drayton, Devin Subject: Peach Valley Vista EXHIBIT Fred - Thank you for the opportunity to review Peach Valley Vista Preliminary Plan. The development consist of 25 single family homes just east of Silt. The main access would be Garfield County Road 235. County Road 235 does access onto US 6. It appears this site will increase traffic by more than 20 percent on CR 235 intersection, therefore, an access permit would be required at County Road 235/ US 6 intersection. The County has the choice to be the permittee/ applicant or have the developer be the permittee for the access permit. If you have any questions, please contact me. Thanks Dan Roussin Region 3 Permit Manager 222 South 6th Street, Room 100 Grand Junction, CO 81501 970-248-7021 970-248-7294 Fax 1 • • GARFIELD COUNTY Building & Planning Department Review Agency Form Name of application: Peach Valley Vistas Sent to: Garfield County Road & Bridge Dept. Date Sent: June 16, 2005 Comments Due: July 6, 2005 o EXHIBIT Garfield County requests your comment in review of this project. Please notify the Planning Department in the event you are unable to respond by the deadline. This form may be used for your response, or you may attach your own additional sheets as necessary. Written comments may be mailed, e-mailed, or faxed to: Garfield County Building & Planning Staff contact: Fred Jarman 109 8th Street, Suite 301 Glenwood Springs, CO 81601 Fax: 970-384-3470 Phone: 970-945-8212 General Comments: Garfield County Road & Bridge Dept. has no objection to this subdivision with the following requests. A 30 -foot ROW from the center line of Cr. 235 and Cr. 214 along the entire length of the subdivision will be deeded to Garfield County. All fences, structures, trees and brush that encumber this ROW will be removed back to the new ROW at the sub dividers expense prior to final platt. . A driveway access permit will issued with conditions specific to the driveway access will be issued upon final approval by the BOCC. A stop sign will be installed at the driveway access entrance to Cr. 235. The sign and installation will be as required in the MUTCD (Manual on Uniform Traffic Control Devices). Name of review agency: Garfield County Road and Bridge Dept By: Jake B. Mall Date 6/28/2005 Revised 3/30/00 June 24, 2005 Fred Jarman Garfield County Building and 108 8th Street, Suite 201 Glenwood Springs, Colorado RE: Peach Valley Vistas Mr. Jarman: • JUN 2 7 2005 GA,RFIE.LD COUNTY BUIL0iNG & PLANNING Planning Department 81601 SERVICE State Services Building 222 S. 6th Street, Room 416 Grand Junction, Colorado 81501 Telephone: (970) 248-7325 T have ...,iced the Prclimin. Plan ut itted f the 7_ .rt_ _ 1 T i i i. _ r 24th. ' � ��•���� �' � .7.: j � i.�.. submitted 'v >,_i, yen property, .�%, G,illi 1 -visited the :�tLC. Vi: Jl1 iIG t:`t , 2005. Kelly Lyon and Brit McLin, the Burning Mountains Fire Protection District's fire chief were present during my site review of the property. I have the following comments regarding wildfire hazard on this proposal. The majority of the lots will be located in, what is now, an irrigated hay field, or a grape orchard, or an open meadow. Only the lots located on the eastern edge of the proposed subdivision will incorporate a slight slope (5--10 %). This slope is covered in grass, hay, and weeds. In terms of wildfire mitigation, the area must be mowed to keep it at a low height. An alternate to mowing would be to plow the unwanted ground cover and re -seed with a local grass seed mix to promote lower wildfire hazard and a healthier ecosystem. Overall, the wildfire hazard on this property is low to moderate. Each lot will have irrigation running to it and an 80,000 -gallon water storage tank will be located within the proposed subdivision. The fire chief has approved the water situation on the property, which also will include at least 4 fire hydrants. My specific recommendations to further mitigate wildfire hazard on this property would be to incorporate defensible space clearing and thinning as outlined in Colorado State Forest Service publication 6.302, "Creating Wildfire Defensible Zones" and use firewise construction when feasible. Copies of these publications were left with the applicant. Also, the grass and weeds must be dealt with to reduce the accumulation of one-hour euels. one-hour tueis are 1/4 inch or cess in diameter and respond . ery quickly to changes in their environment. Mowing or re -seeding can be done to reduce the intensity or possibility of a grass fire in the proposed subdivision. The landowner should manage the weed infestation by preventing the spread and improving the health of the land. Thank you for the opportunity to review this proposal. Please call me with any questions at 970-248- 7325. Kamie Fuller -Long Forester Cc: Kelly Lyon, Chief Brit McLin • • Fred Jarman EXHIBIT From: Gleason, Andy [Andy.Gleason@state.co.us] Sent: Thursday, June 23, 2005 2:22 PM To: Fred Jarman Subject: Land Use Review- Peach Valley Vistas June 23, 2005 Legal: WSWS1, T6S, R92W Fred Jarman Garfield County Planning Dept 108 8th St. Suite 201 Glenwood Springs, CO 81601 Re: Peach Valley Vistas CGS Review No. GA -05-0009 Dear Mr. Jarman; In response to your request and in accordance with Senate Bill 35 (1972), I visited the site and reviewed the site plan on June 21, 2005. The site consists of approximately 54.8 acres and the proposed subdivision would split the existing property into 25 residential lots. Water service will be centralized and sanitation services will be by individual sewage disposal systems. Included in the review package were a preliminary plan report by Gamba & Associates, Inc. (3- 25-05), a preliminary plan, drainage map, water layout map, ISDS map, and a yield plan by Gamba & Associates, Inc. (3-24-05), a Geologic Evaluation and Preliminary Geotechnical Investigation by CTL Thompson, Inc. (2-20-03), a Subgrade Investigation and Pavement Design report by CTL Thompson Inc. (2-20-03), a NRCS Soil Information report and a Drainage Report by Gamba & Associates, Inc. (3-14-05). The following are concerns I have with the development. 1. Rockfall. The Geologic Evaluation by CTL Thompson outlines an area of existing rockfall hazard in the southwest corner of the property. They also outline a larger area of rockfall hazard "...without the existing ditch or after filling ravines. " Rockfall mitigation must accompany any building within these zones. A rockfall analysis model, such as CRSP, must be conducted before approval of building lots in the rockfall hazard zone in order to determine the impact pressures of probable rockfall in the area and to design mitigation. There are areas within the property that do not have rockfall hazard and it would be less costly to simply move the lots platted within the rockfall hazard area to safe areas. 2. Erosion. The loess in the southwest part of the property is conducive to piping, which is the removal of 6/23/2005 • Page 2 of 3 soluble or easily eroded layers beneath the ground surface by running water. There is evidence of piping at the ground surface adjacent to the drainage from the Ware and Hines ditch (noted as the ravine in the southwest part of the site by CTL Thompson). Piping was evident up to 70 feet from the edge of the ravine. The depth of the piping is undetermined and there is the potential for void spaces beneath the ground surface that are not evident from surface inspections. The area in the vicinity of Lots 16, 17 and 18 is conducive to piping and should be inspected by a geotechnical engineer before actual construction begins to insure that there are no voids that could undermine a foundation. If any void spaces are encountered, then the Geotech engineer will need to determine if mitigation is possible in this area. In the Geologic Evaluation and Preliminary Geotechnical Investigation, CTL Thompson states, "Some areas along the side of the ravine exhibit evidence of "recent" or "active" instability." The banks along the side of the ravine are experiencing severe erosion. Setbacks from these banks may have to be up to 150 feet in order to avoid erosion problems due to piping. Setbacks that are large enough to avoid erosion hazards may not leave enough room on Lots 16-18 for building envelopes. I recommend against building in this area without mitigation. 3. Drainage. The wetland area in the east -central part of the property appears to be a spring and is not recharged from surface flow. On the Yield Plan (sheet No. Y1) there are 40 foot wide Drainage Easements proceeding in a southerly direction from the wetlands area. These drainage easements are not shown on the Preliminary Final Plat (sheet No. P2). There are building envelopes platted in the middle of the drainage easements in lots 10 and 11 as shown on sheet No. 1. The preliminary plat should show these drainage easements. Building envelopes should avoid drainage easement areas. 4. Soils/Subsurface. Some of the soil units described in the NRCS Soil information report indicate that the soils are poorly suited to home site development. This is mostly due to the potential for swelling soils. Due to the low number (four) of exploratory borings for foundation analysis, site-specific geotechnical investigations are recommended to determine if any mitigation is necessary to mitigate against swelling soils. 5. Fill. There are areas in the east part of the property that have existing man-made fill according to the Geologic Evaluation and Preliminary Geotechnical Investigation by CTL Thompson, Inc. All fill must be removed and reworked into structural fill per standard geotechnical specifications prior to construction. In conclusion, the southern part of the property has more geologic hazards than the north part of the property, yet all the development is planned for the south part. There is ample room in the north part of the property for building lots that are free from most of the geologic hazards discussed in this letter. If the developer wishes to continue with the development of the southern portion of the property, then extensive mitigation will be necessary to mitigate the numerous geologic hazards. I recommend against approval of this subdivision until the concerns outlined in this letter are addressed. If you have any further questions or concerns, please contact me at (303) 866-3350, or andy.gleason@state.co.us Sincerely, 6/23/2005 • • Page 3 of 3 Andy Gleason Geologist The information contained within this email is intended for the addressed recipients only. Any other use of this information is prohibited. 6/23/2005 STATE OF COLO OFFICE OF THE STATE ENGINEER Division of Water Resources Department of Natural Resources 1313 Sherman Street, Room 818 Denver, Colorado 80203 Phone (303) 866-3581 FAX (303) 866-3589 www.water.state.co.us JUL 0 5 2005 BUILDING & Fred Jarman Garfield County Planning Dept 108 8th St Ste 201 Glenwood Springs CO 81601 N NG June 30, 2005 Re: Peach Valley Vistas Subdivision Preliminary Plan Section 1, T6S, R92W, 6TH PM W. Division 5, W. District 39 EXHIBIT L. Bill Owens Governor Russell George Executive Director Hal D. Simpson, P.E. State Engineer Dear Mr. Jarman: We have reviewed the above -referenced proposal to subdivide a parcel of approximately 54.88 acres into 25 residential lots with one single-family dwelling on each lot. The applicant proposes to supply domestic water through two existing wells (Permit Nos. 61981-F and 61982- F). Sewage disposal is to be through individual septic systems. Irrigation water will be provided through shares in the Ware and Hines Ditch. The submittal included a copy of the Domestic Water Supply System report by Gamba & Associates, Inc., copies of Well Permit Nos. 61981-F and 61982-F, and a copy of approved West Divide Water Conservancy District (the District) Water Allotment Contract No. 020530PVV(a). No information was provided regarding the Ware and Hines Ditch. Permit No. 61981-F was issued on November 15, 2004 for the Lyon Well No. 1 for a maximum pumping rate of 14 gpm. Permit No. 61982-F was issued on November 15, 2004 for the Lyon Well No. 2 for a maximum pumping rate of 27.25 gpm. The two wells in combination are permitted to withdraw an average of 13.665 acre-feet annually for fire protection, ordinary household purposes inside 25 single-family dwellings, irrigation of not more than 3000 square feet of home gardens and lawns per residential site and watering of 25 head of non-commercial domestic animals, with total irrigation not to exceed 1.72 acres of home gardens and lawns. A Well Construction and Test Report for the Lyon Well No. 1 was received on July 5, 2002 under previously issued Permit No. 239419. A Well Construction and Test Report for the Lyon Well No. 2 was received on October 21, 2002 under previously issued Permit No. 243224. No Pump Installation and Test Reports have been received for these wells. The applicant should submit Pump Installation and Test Reports to our office to complete the files for these permits. The April 6, 2005 report by Gamba & Associates, Inc. indicates that the Lyon Well No. 1 produced 27.25 gallons per minute over twenty-four hours on September 30, 2002 and October 1, 2002, that the drawdown was 4.43 feet and that the 97% recovery occurred within 60 minutes. The report also indicates that the Lyon Well No. 2 produced 14 gallons per minute over twenty-four hours on June 3-4, 2002, that the drawdown was 78.7 feet and that the 89% recovery occurred within 60 minutes. If the Lyon Well No. 1 continues to produce at this rate, the water supply should be physically adequate. Fred Jarman Peach Valley Vistas Page 2 June 30, 2005 The report by Gamba & Associates, Inc. indicates that total annual water diversions and consumption for the development will be 13.665 acre-feet and 5.012 acre-feet, respectively. The approved contract from the District is for 5.26 acre-feet of water. Based on the above, and pursuant to CRS 30-28-136(1)(h)(I), it is our opinion that the proposed domestic water supply will not cause material injury to decreed water rights, so long as the applicant obtains and maintains valid well permits. However, due to a lack of information, we are unable to comment on the legal and physical adequacy of the irrigation water supply. If you or the applicant has any questions concerning this matter, please contact Cynthia Love at this office for assistance. Sincerel Craig M. Lis, P. . Water Resource Engineer CML/CJL/Peach Valley Vistas.doc cc: Alan Martellaro, Division Engineer, Division 5 James Lemon, Water Commissioner, District 39 EXHIBIT MEMORANDUM To: Fred Jarman From: Steve Anthony Re: Comments on the Peach Valley Vistas Preliminary Plan Date: July 6, 2005 Thanks for the opportunity to review the preliminary plan. My comments are as follows: Noxious Weeds The applicant has provided a noxious weed inventory, however they have not provided a follow-up plan for the inventoried noxious weeds. A copy of the Garfield County Weed Management Plan is not a substitute for a written commitment to weed management. Common area weed management is not addressed. Who will be responsible for weed management on roadsides, common open space and undeveloped lots? Revegetation The applicant has not provided a revegetation plan that includes a plant materials list for review. Please quantify the area, in terms of acres, to be disturbed and subsequently reseeded on road cut and utility disturbances. This information will help determine the amount of security that will held for revegetation. Staff recommends a revegetation security once this information is provided. Soil Plan It is requested that the applicant provide a Soil Management Plan that includes: Provisions for salvaging on-site topsoil. A timetable for eliminating topsoil and/or aggregate piles. A plan that provides for soil cover if any disturbances or stockpiles will sit exposed for a period of 90 days or more. Christine Burke P.O. Box 346 Silt, CO 81652 July 24, 2005 Garfield County Planning and Zoning Commission 108 8th Street Glenwood Springs, CO 81601 RECEIVED AUG 0 ). 2005 GARFIELD COUNTY BUILDING & PLANNING RE: Preliminary Plan Review for Peach Valley Vistas Subdivision proposed by Kelly and Michael Lyon Family, LLC Dear Commissioners: I am writing to express my concerns about the proposed Peach Valley Vistas housing development. You have already seen the engineering reports about water quality problems with the well water, and the potential for flooded basements because of the agricultural irrigation. However, the issue which concerns me the most relates to additional traffic on Davis Point Road. Davis Point Road is a narrow, winding rural road with no center line, no shoulders, no sidewalks, and extremely poor visibility at its intersection with Highway 6. In its current state, it cannot safely support the increased number of vehicles, bicycles, and pedestrians that would use the road if the new houses were built. A driver who is on Davis Point road, wishing to turn left (east) onto Highway 6, cannot see the traffic that is coming from the town of Silt to the west. To make the left turn, one must inch out onto the highway as far as possible, and then "floor it" in order to avoid being struck by the vehicle that has suddenly appeared from behind the retaining wall, going 55 miles per hour. Similarly, a vehicle that is on the highway headed east from Silt cannot see one that is turning onto the highway from Davis Point—until the last moment when it emerges. Blinding sun in the morning and the evening makes the situation even worse. Unless the road is improved significantly, the new residents of Peach Valley Vistas would not have a safe way to drive, walk, or bike to work or to school. The developer proposes to make a significant change in the population density of the neighborhood. That developer should be made responsible for road improvements including sidewalks, a safer intersection at Davis Point and Highway 6, and a bus stop on Highway 6 near the intersection. I have enclosed some photos to illustrate the problems. Sincerely, CJI ni`� dc_sz Christine Burke Peach Valley Resident enclosures Traveling south on Davis Point Road On Davis Point Road at the intersection with Highway 6—trying to see the traffic coming from Silt On Davis Point Road at the intersection with Highway 6 Headed east from Silt on Highway 6 Photos taken by Christine Burke on July 24, 2005., and submitted to the Garfield County Planning and Zoning Commission. RECEIVED AUG 0 8 2005 GARFIELD COUNTY BUILDING & PLANNING Planning Commission Garfield County, Colorado 108 8t` Street, Suite 201 Glenwood Springs, CO 81601 RE: Preliminary Plan Review for Peach Valley Vistas Subdivision Proposed by Kelly and Michael Lyon Family, LLC Dear Commissioners: b a EXHIBIT PO Box 346 Silt, CO 81652 August 8, 2005 I own property and reside at 3467 County Road 214 in Garfield County, directly across the road from the proposed subdivision. I have lived there for 18 years. For 14 of those years I commuted daily to and from Glenwood Springs, driving through the property already subdivided by the Lyon LLC (hereinafter Lyon) as well as the other Lyon subdivisions adjacent to the Town of Silt. The proposed Preliminary Plan should be denied for the following reasons: 1. The proposal is in sharp contrast to the residentiaUagricultural character of the neighborhood. The average size residential property within a %2 mile radius of the proposed subdivision (not including the Lyon property) is 8.8 acres. The cluster development proposed by Lyon would drastically change the density of housing in the area. 2. The proposal would dramatically increase vehicular and pedestrian traffic on Peach Valley and Davis Point Roads, both of which are already unsafe. Approximately 40 residences now depend on Davis Point Road as primary access to Highway 6, Interstate 70, and the communities of Silt and New Castle. 4 of these residences are part of a previous Lyon subdivision of the former Nelson property. The proposed subdivision will increase the number of residences dependent on Davis Point Road by 60%. If the subdivision is built as planned, over 43% of the total residences dependent on Davis Point Road will be attributed to Lyon. The intersection of Davis Point Road (County Rd 235) and Highway 6 is recognized as a high hazard situation by the Colorado Department of Transportation (personal Page 1 of 4 communication with Jim Nall, Region 3 Traffic and Safety Program Manager). The sight distance for traffic attempting to turn onto Highway 6 from Davis Point is substandard, and the angle of the intersection makes it difficult to enter and exit. The position of the sun creates very dangerous conditions at commuting time (morning and evening) for weeks at a time every year. The proposed subdivision will make conditions worse and increase the probability of serious accidents. There is no safe pedestrian access to the new Coal Ridge high school or to Silt from the proposed subdivision. The increase in population and pedestrian/bicycle traffic justifies construction of a path parallel to the entire length of Davis Point Road and both east and west along Highway 6. 3. The proposed subdivision plan would transfer liability for a serious erosion problem and possible violation of the federal Clean Water Act from Lyon to Garfield County residents in the Homeowners Association. Between the time Lyon was granted the Exemption and the present application, a substantial amount of earthwork was conducted in and adjacent to a watercourse at the south end of the 54 -acre parcel. This is the 6.55 acres identified as OS -2 on the plat and proposed as "common open space." Lyon placed fill material, including soil and concrete debris, in a channel carrying water from a spill structure on the Ware & Hinds Ditch. This channel begins at the outfall of a culvert under County Road 235, passes beneath the Lower Cactus Valley ditch, then enters a wetland north of Highway 6 &24 and ultimately the Colorado River. Before the earthwork by Lyon, the area was characterized by steep banks and heavy brush. It was unattractive, but stable. The modifications performed by Lyon have created a hazard, and the Army Corps of Engineers has no record of a permit for the work. The Geologic Evaluation and Preliminary Geotechnical Evaluation included in the plan documents states: "some areas along the side of the ravine exhibit evidence of recent or active instability." The Colorado Geologic Survey observed that the "banks along the side of the ravine are experiencing severe erosion. Setbacks from these banks may have to be up to 150 feet in order to prevent erosion problems due to piping." County Road 235 is inside the 150 -foot limit. Lyon's attempts at controlling the modified channel have been a complete failure. Erosion continues out of control in the loose soil. Ponds created by Lyon in the channel were almost immediately filled with sediment. In the spring of 2005, Lyon resorted to placing concrete erosion barriers in the stream bed. The concrete has been undermined and is lying in the channel, with erosion continuing on both sides. The channel continues headcutting toward the county road, and threatens to undermine the road at a location which would be very expensive to fix. Lyon proposes to deed this area and its associated problems to the Homeowner's Association, which will be "responsible for repair and maintenance of this parcel." The proposed plan would conveniently transfer ownership Page 2 of 4 of the problem to lot purchasers. Garfield County must not take any action to facilitate this shift of liability to innocent people buying lots from Lyon. 4. The irrigation water supply plan is inadequate and results in injury to other water rights. At the time Lyon was granted an Exemption for the 4 lots west of Davis Point Road, lot purchasers were sold shares in the Ware & Hinds Ditch, which lies east of the road. All 4 lots lie uphill from the ditch. Pumping ditch water up to the lots sold by Lyon without benefit of a plan for augmentation/change of place of use and a permanent dry -up of an equal amount of acreage below the ditch is illegal and an expansion of use of the Ware & Hinds water rights. Now Lyon proposes to convey shares in the Ware & Hinds Ditch to homeowners in Peach Valley Vistas. Lyon has not identified how many shares will be allocated to each lot or reconciled the acreage being served below the ditch with the acreage served on lots in the Exemption. Unless Lyon can demonstrate that equivalent acreage below the Ware & Hinds Ditch is permanently removed from irrigation pursuant to a plan approved by the Colorado Department of Water Resources and adjudicated by the District Court, other water rights are injured by Lyon's expansion of historical irrigated acreage. Again, Lyon proposes to transfer a liability to unwitting buyers of lots in Peach Valley Vistas. Suggested Terms and Conditions The Proposal should be denied for the reasons already stated. If the Planning Commission decides to conditionally approve the preliminary plan, the following conditions should be considered, at a minimum: 1. Lot size should be at least 8 acres to conform to the average density of the area. The number of units should be reduced to fit the safe building site. 2. Lyon must be responsible for upgrades of the Highway 6/Davis Point Road and the Davis Point/Peach Valley Road intersections. 3. Lyon must be responsible for a safe pedestrian route connecting Peach Valley Road with the path already constructed east of Silt. 4. Lyon must be required to obtain a District Court decree identifying the acreage and amounts of water involved in the change of use of Ware & Hinds Ditch rights proposed for this subdivision, specifically referencing the acreage served on lots already developed by Lyon under the previous Exemption. 5. Lyon must be required to get professional help in controlling the erosion problem on the 6.55 -acre open space, and to complete the erosion control and any other mitigation prior to selling any lots in Peach Valley Vistas. Page 3 of 4 6. Lyon must be required to obtain all relevant state and federal permits and provide proof of compliance to Garfield County and adjacent landowners on request. C: Lyon Family Ltd Fred Jarman Michael Erion Very truly yours, 6.(-i Michael R. Gross Page 4 of 4 GARFIELD COUNTY Building & Planning Department Review Agency Form EXHIBIT Date Sent: June 16, 2005 Comments Due: July 6, 2005 **Please note that the (complete??) application was send on an electronic disk to the Town on June 16, 2005; however, no hard copy was received by the Town until 7/6/05. Name of application: Peach Valley Vistas Subdivision Sketch Plan Sent to: Town of Silt Garfield County requests your comment in review of this project. Please notify Kit Lyon in the event you are unable to respond by 11/22/00. This form may be used for your response, or you may attach your own additional sheets as necessary. Written comments may be mailed, e-mailed, or faxed to: Garfield County Building & Planning Staff contact: Fred Jarman 108 8th Street, Suite 201 Glenwood Springs, CO 81601 Fax: 970-384-3470 Phone: 970-945-8212 E-mail: unknown General comments: The Town of Silt Planning & Zoning Commission was unable to review this application at their regular meeting of July 5, 2005 due to the fact that the full application was not received until July 6, 2005. On February 19, 2002, the Planning & Zoning Commission discussed the following points regarding this proposed subdivision sketch plan (boldened comments are staff comments related to the preliminary plan): 1) The Individual Sewage Disposal Systems (ISDS) that are proposed have been shown to pollute groundwater. A better alternative may be to require Individual Sewage Treatment Systems (ISTS); 2) Putting 23 single-family homes adjacent to Davis Point Road begs the obvious question: Will Davis Point and Highway 6 be improved to handle this increased traffic? The retaining wall on Highway 6 was recently built to mitigate the falling mountain, but has made the intersection increasingly dangerous for motorized and non -motorized traffic. Did this developer receive a CDOT access permit as is required when there is a 20% increase in traffic at an intersection with a state highway? 3) The Town of Silt has received pressure to build trails on its border due to specific growth the Town has experienced, such as the new medical clinic and the post office. Might Garfield County require this developer to construct off-site improvements in order to service their own developments? The Town of Silt has been thrust into the position of providing a trail down to the new high school; this development would necessarily increase the need for a trail on Highway 6. 4) Might the developer consider a clustering of the lots in order to provide more common open space? It is very encouraging that the clustering idea has been proposed at preliminary. 5) Might the developer contact Garfield County Housing Authority to determine if the Authority could be of any assistance in providing affordable housing? 6) This developer contacted the Town with regards to receiving town services (water and sewer); the Silt Board of Trustees did not approve the request, stating that this property was not appropriate for town development (annexation), but that the developer could negotiate with the town for out-of-town taps. No further contact has been made by this developer. The Town of Silt appreciates the opportunity to comment on a subdivision that is within the Town's area of influence. Should you have any questions about these comments, please do not hesitate to call, Monday through Friday, from 8 a.m. to 5 p.m. Sincerely, Janet G. Steinbach, Community Development Director EXHIBIT F, P JUL 0 8 2005 GARFIELD C. �rY BUILDING & PLANi iNG Fred Jarmen Garfield County Building and Planning 108 8th Street Suite 201 Glenwood Springs, Co 81601 Dana Yerian 3550 County Road 214 Silt, Co 81652 876-5735 July 5, 2005 RE: Preliminary plan review for Peach Valley Vistas Subdivision Dear Sir; I have reviewed the application and associated documents pertaining to this proposed subdivision and have the following concerns and questions. 1. Davis Point road (235 Road) is a very narrow road with the Ware and Hinds ditch running parallel to it at the point where the entrance to the subdivision is planned. Vehicles have landed in that ditch at that area in the past. My fear is if that portion of the ditch is not covered completely down to the south culvert going under 235 road, and the road not widened (preferably from end to end) or at the ver least, turning lanes installed at the entrances, the possibilities of someone lrunning o in o e ditch o avoid an oncoming car turning in or pulling out of the entrance are cause tor great concern. This narrow road is a considerable problem with the traffic flows as they are, let alone with the addition of 50 more vehicles. 2. While talking about the Ware and Hinds ditch my next concern is to address the JTegaf usage, the monitoring of, and the metering of this water distributed by underground irrigation line to each property. The traditional method of allocation is based on one share per acre, however this method has not been adhered to. What method is used by the developer needs to be known, and in legal form so the ditch company can assess the property owner and the parcels plus the "large lot" and should require metering to assure accurate allotments. If this ditch is left open through out any part of this proposed subdivision the developer should assure the ditch company in writing that they assume every and all liabilities for any problem arising from said open irrigation ditch. 3. It has my assumption that after a parcel of land is subdivided whether by exemption or by other means it is no longer dividable. It appears I may have been wrong, however I'm sure there must have been some "fine print" I did not catch in my interpretation of the county codes and regulations since this application is being considered. But if this should ha will put a lot of thought into preservingllot # 25 with some kind of deed restriction as an Agricultural Easement or something to keep it from ever being subdividable again. 4. Even though these preliminary plans, specifications, and information were compiled by engineers I do hope you take great effort ir1establishing requirements for engineered foundations, irrigation and domestic water systems, engineered septic s ste and storm draina e with particular concern for 5. 0 er items I did not see addressed, and hopefully did not overlook: a. tNlamtenance tf all systems and common use areas. b. rest con'trooanimal control, and weed control c. Concern of current land owners privacy and quality of life. This subdivision will create more noise, more traffic and congestion, and more crime in an area that has already been impacted by too much development. 6. Please consider also that the county assessor's office is presently considering the property values in this area as high and is changing assessments accordingly. Therefore please do not make any decisions or allow just anything to happen on tha *ha*=ruse the property owners in that area to dispute or otherwise contest the present assesse vd- a—Tues Sincerely, ®. . . '.®RESOURCE . ••.•• ■ ■■■■ E N G I N E E R I N G I N C. Mr. Fred Jarman Garfield County Building and Planning Department 108 Eighth Street, Suite 201 Glenwood Springs CO 81601 b a EXHIBIT July 11, 2005 RE: Review of the Preliminary Plan Submittal for the Peach Valley Vistas Subdivision Dear Fred: At the request of Garfield County, Resource Engineering, Inc. (RESOURCE) has reviewed the preliminary plan submittal for the proposed Peach Valley Vistas Subdivision located at the intersection of County Roads 214 and 245 near Silt. The submittal includes a spiral bound package dated April 6, 2005 and engineering drawings (9 sheets) stamped and dated June 6, 2005. We reviewed the technical issues related to water rights and water supply, wastewater, drainage, soils/ geology wetlands, and traffic/road. Our comments are presented below. WATER RIGHTS AND WATER SUPPLY The 25 lot subdivision is proposed to be served by a central water system utilizing at least two wells, a treatment system, an 80,000 gallon storage tank, and a distribution system with provision for fire flow. Lyon Well No. 1 and No. 2 have been drilled and tested. The in-house water demand is conservatively estimated at 10,000 gallons per day (7 gpm). The two wells appear to be adequate to meet this demand. The water quality of the wells indicates that several parameters exceed primary and secondary drinking water standards. A central water treatment system is proposed to address the water quality issues with the well water. The Burning Mountain Fire Protection District serves the project area. Fire Chief Brit McLin, has outlined requirements for the project. These requirements have been included in the water system design. The proposed central potable water system must be reviewed and approved by the CDPHE. In accordance with GARCO regulations, such approval is required prior to Final Plat. The legal water supply is based on well permit Nos. 61981-F and 61982-F issued by the Division of Water Resources pursuant to West Divide Water Conservancy District water allotment contract No. 020530PVV(a). The contract should be conveyed to the HOA and the convenants should identify that the HOA must maintain this contract for the potable water supply. A central raw water irrigation system is proposed for the project. A portion of the Ware and Hines Ditch shares owned by the Applicant will be conveyed to the HOA. The balance of the water rights will be used for continued irrigation of agricultural lands on Lot 25. Consulting Engineers and Hydrologists 909 Colorado Avenue W Glenwood Springs, CO 81 601 '9z (870) 945-6777 E. 9P JUL 1-1 2005 Mr. Fred Jarman Page 2 WASTEWATER July 11, 2005 Individual sewage disposal systems (ISDS) are proposed for the subdivision. Lots 1-24 are generally one acre lots. The Gamba and Associates analysis indicates that ISDS systems can physically be arranged on the lots to meet setback requirements. The percolation tests indicateLvery slow percolating soirsl Due to the tight site constraints, shallow ground water and slow percolating soils, a plat note should be added that requires a S systems to be designed by a registered professional engineer. The density of ISDS stems should be evaluated in terms of the resultin• pollutant load Although the water system includes a treatment . - a wi remove ISDS pollutants, there is a potential impact to others. Th an ysls should be done • •• .. Plat and s•ecificall address whether individual sewage treatment systems ISTS should be constructed to reduce effluent concentrations of nitrogen, osphorus, and BOD. DRAINAGE There are two minor drainages and a ditch wasteway which traverse the project. Off-site and on-site drainage contribute to the water in these flow paths. The drainage analysis adequately analyzes the 25 year and 100 year flood flow events. Adequately sized culverts and detention ponds are proposed for the project. The sediment and erosion control plan (including revegetation) should be included in the Final Plat submittal. Appropriate drainage easements have been included on the proposed plat. SOILS/GEOLOGY Site constraints include high groundwater, rockfall from the hills to the west and soils which are subject to differential movement when loaded or wetted. Based on these conditions, we recommend that a plat note be added requiring that individual site specific geotechnical investigations and foundation design be submitted with the building permit application. The limits of the rockfall hazard • • • • - • • - • • • - • layout map to compare the location of the building envelopes for Tots 13 through 18 wi h the hazard boundary. We recommend that building envelopes should be located outside of both rockfall hazard boundaries delineated by CTL Thompson. WETLANDS Jurisdictional wetlands have been delineated and shown on the plat map. The proposed plan avoids wetland areas. The sediment and erosion control plan referenced above should include measures to protect the wetlands from construction activities. RESOURCE ■•EEE E N G I N E E R I N G INC Mr. Fred Jarman July 11, 2005 Page 3 TRAFFIC/ROAD The average daily trip (ADT) for the project was calculated at 255 vehicle trips. This requires the internal road system to be designed as a secondary access including a 50 foot right-of-way with two 11 foot lanes and 4 foot shoulders (30 feet paved). The proposed design provides two 12 foot lands and 3 foot shoulders (30 feet paved). The subdivision has a single point of ingress/egress for traffic. An emergency secondary point of ingress/egress should be provided. The traffic pattern to and from the subdivision area will generally be along County Road 235 to its intersection with Highway 6 and 24. The County's 2002 vehicle trip count for County Road (CR) 245 was 307 vehicles per day. Conservatively assuming only half of the proposed subdivision traffic uses the CR 235/Hwy 6 & 24 intersection, the highway access traffic would increase by more than 20 percent. According to CDOT access regulations, the County (or the Applicant in this case) would need to obtain a new highway access permit. Due to the limited sight distance at the CR 235/Hwy 6 & 24 intersection, improvements would likely be required. Consistent with a similar situation at Miller Lane/Hwy 6 & 24 intersection (Mamm's View Subdivision), the applicant should identify any improvements required by CDOT and they should be included in the proposed project. ENGINEERING DRAWINGS The engineering drawings are generally adequate for preliminary plan. The details for water system, drainage structures, and erosion/sediment control measures should be included at final plat. Please call if you have any questions or need additional information. Sincerely, RESOURCE ENC, INEERING, INC. ff , Michael J. on, P.E. Water Re ource Engineer MJE/mmm 885-35.0 E:\Client\885\fj peach valley vistas sub prelim plat 885.doc Mr. Mike Gamba RESOURCE NCINEEPING INC Garfield County Public Health Memorandum 902 Taughenbaugh,#1 Rifle, CO 8165 PH (970) 625-520 FX (970) 625-48 EXHIBIT 1 S To: Fred Jarman, Senior Planner From: Jim Rada, Environmental Health Manager Date: September 6, 2005 Subject: Peach Valley Vistas Subdivision Preliminary Plan Application, ISDS Issues I have reviewed the proposal for the above referenced subdivision as it pertains to the proposed drinking water and individual sewage disposal system (ISDS) plans. I do not have specific experience to qualify me to review the water system proposal. However, because a subdivision this size requires CDPHE approval for the water system, the CDPHE engineers should thoroughly review the proposal and give any necessary plan change requirements to the landowner and the County prior to final plat approval. Although I am not a licensed professional engineer, I do have extensive experience and credentials that qualify me to review ISDS plans, particularly as they relate to state and local regulations. That said, I want to outline some of the issues I have identified with the referenced proposal. 1. The percolation test data on page 199 of the Preliminary Plan Report (Appendix L) indicates percolation rates of 240 minutes per inch (mpi), 240 mpi and 213 mpi recorded at three test holes spread across the subject property. These percolation test results are consistent with the soil boring logs found in Appendix F. According to the soils information contained in Appendix G, soil types 4, 29, 30 and 34, located on 18-19 of the proposed lots, are moderately to severely limited for urban uses. These limitations are based on moderate to low permeability and shrink/swell potential. Although this data may not be representative of each individual site, the location of the test holes along with the soil survey information suggests that similar percolation test results could be expected across a large area of this subdivision. 2. In many ISDS design review programs across Colorado, the 240 mpi soils on this site would be considered unsuitable soils for ISDS at least on lots this size. I spoke to Andy Schwaller and he indicated that this issue is addressed in Garfield County by requiring an engineer's design for any parcel with such soils. Although this may not be the most appropriate solution to this issue, this requirement is consistent with the State ISDS Guidelines. LJV11U1L1U11, 41UJJ LUG G11UiG UG VG1VL7111G11 L, UUL L11GJG LGJLJ UV 111U1GaLG LllaL aUUILlV11G1.1 IV LZ, 3. Soil boring data in Appendix F indicates the presence of bedrock and groundwater at 2 feet and 10 feet respectively in test holes 3 and 4. Both holes appear to be in the area of the proposed development. Again, the limited number of holes may not represent actual conditions across the entire development, but these tests do indicate that additional lots could be limited or restricted by subsurface conditions. 4. The ISDS calculations included in Appendix L do not include the water -use appliance factor as required by the Garfield County Building Department (I confirmed this requirement with Andy S.). The Building Department requires an additional 60% factor be added to leach field area calculations to accommodate the use of garbage disposals and other water -use appliances used in typical residential developments. As such, the additional factor would increase a system with 240 mpi soils from 2789 to 4462 square feet, approximately 10% of a 1 -acre lot. Based on the proposed ISDS map, additional leach field area requirements could preclude a number of these systems from being built based solely on available area and mandatory setback requirements. 5. The information submitted regarding the use of Infiltrator Systems, Inc. chamber units for leach fields has several flaws. Required areas aside, the proposal calls for a 126 unit leach field with 9 rows of 14 units laid out in a bed configuration. The plan also calls for a total trench width of 3.42 feet created by separation between rows. The plan also indicates that each unit is 6 feet by 3 feet for a total square footage of 18 square feet per unit. The CDPHE Water Quality Control Division issued a letter several years ago giving Infiltrator Systems, Inc. only 15.5 square feet of open bottom area credit for a standard chamber unit (not the 20.5 feet indicated in the proposal). I confirmed with Andy S. that Garfield County uses this number. I also confirmed with Mr. Eric Berquist of Infiltrator Systems, Inc. that this number has not changed. Based on 15.5 square feet per unit, the minimum number of chambers required by state and local policy for the example provided and the square footages stated in #4 above would be 180 and 288 units respectively. Furthermore, the actual footprint of the Infiltrator chamber is 18.75 square feet so the associated excavation for these systems would be 3375 and 5400 square feet. Also, assuming these systems could fit on the properties, the cost for Infiltrator units (based on Gamba and Associates information) would increase from the suggested $3528.00 to $5040.00 or $8064.00. 6. It is reasonable to assume that individual systems in poor soils will inevitably be used (or abused) in a manner that may result in leach field failure. The limitations imposed on many of the lots, either by site features or yet to be determined building locations, may preclude a large number of these lots from installing a replacement leach field except in the original location. This situation could be extremely problematic due to existing soil limitations and soil saturation when failure occurs. 7. To avoid problems with mandatory separation to bedrock and groundwater requirements and to maintain the most optimum soil conditions to promote soil treatment of effluent, it is important to keep leach fields as shallow as possible and at a consistent depth. The ISDS Map included in the preliminary plat proposal shows that a number of leach fields, particularly those closest to Davis Point Road, will be installed in areas with an elevation change of 4-10 feet across the designated leach field area. According to the ISDS guidance on the Garfield County website, leach fields are typically installed at about 4 feet deep to take advantage of gravity flow from the tank to the leach field. As such, some of these fields may require up to 14 foot excavations in areas. This creates possible conflicts with the groundwater and bedrock separation requirements and is far from optimal in terms of promoting effluent treatment in the soil. 8. Although it is not generally a consideration of the platting of a subdivision, installation of leach fields in such difficult soils can be a formidable challenge. Once these soils are disturbed, what structural characteristics that may have existed are, for the most part, no longer existent. Furthermore, if the soils are wet or subjected to vehicular traffic, substantial smearing and/or compaction will take place thereby reducing the already marginal permeability. Because the proposed leach fields would require such large excavations, it may be difficult to excavate without driving equipment into the excavations. Serious consideration should be given at this stage and must be given by the individual system designers and installers as to the location and configuration of the leach field along with the necessary space to operate equipment. Recommendations 1. More percolation tests and profile hole inspections should be done prior to preliminary plat submittal to get a better handle on soil conditions of each lot. Should soil conditions be relatively consistent as currently described, then consideration should be given to alternative system design, pretreatment of wastewater before discharge, use of open space for absorption area, clustering systems, increasing lot sizes, etc. 2. Consideration should be given to require that an appropriate area be reserved on each platted lot for leach field replacement. Prohibitions for use of these areas should include construction of buildings, animal corrals or pens, vehicular traffic and anything else that may result in soils compaction or changing of original soil characteristics. Some sort of recorded documentation on the deeds to the property should include these restrictions. 3. Initial and any subsequent site grading should avoid all areas where leach fields are planned to maintain original grades and soil conditions. 4. If this subdivision is approved, a detailed, specific ISDS management plan should be required of the applicant and subsequent homeowners to assure that these systems are systematically and properly inspected and maintained on a regular basis. Thank you for your consideration of my professional opinion of the material as submitted. I will gladly speak with you at your convenience concerning any questions you may have about my position on these matters. 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