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HomeMy WebLinkAbout4.0 Staff Report PC 03.11.98REOT]EST: APPLICANT: ENGIITIEERS: LOCATION: SITE DATA: WATER: SEWER: ACCESS: ZOITTING: PROJECT INT'ORMATION A}ID STAFF COMMENTS PC 3fiit98 Preliminary Plan for the Los Amigos PUD filings 6 thru 10 Los Amigos Ranch Partnership Schmueser Gordon Meyer, Inc. A parcel of land located in portions of Sections 35 and 36, T65, R89W; portions of Sections 31,32 and 33 of T65, R88W; portions of sections 5 and 6 T7S, R88W of the 6th p.M.: more practically described as a tract of land located approximately two (2) miles southeast of Glenwood Springs offof C.R. 114. 1703.058 acres Central water ISDS County Road 114 Planned Unit Development I.RELATIONSHIP TO TIIE COMPREIIF'NSIYE PLAN The PUD is located in the existing subdivision classification for Study Area I of the 1995 Comprehensive Plan. The Plan recognized the original PUD approved and modified in l98l and 1996. -t- IL DESCRIPTION OF TIIE PROPOSAL A. Site Description: The property is located south of Glenwood Springs, in the southwest portion of Spring Valley. Elevations range from 6400 to 7175 feet. The site is generally situated on the upland portion of a ridge that slopes from the north to the south to the Roaring Fork river valley approximately 800 ft, with slopes ranging from 4oh to over 9002. The steeper slopes have vegetation consisting primarily of pinion/juniper trees and sagebrush/grasses. The upland area consists of some fairly gentle rolling terrain, with slopes generally less than 10%. Portions of the upland area is existing agricultural lands. A vicinity map is shown on the enclosed plan map. B. Project Description: The proposed subdivision includes five (5) separate filings of the approved Los Amigos PUD. Filings 6-10 consist of 168 single family lots on a total of 1703.058 ac. of land, of which975.927 ac. is Open Space. There are four Rural Residential lots totaling 223.6 ac. or an average of 55.9 ac. in size. The remaining 164 single family lots cover an area of 503.6 ac. with an average lot size of 3.1 ac. each. The remainng 4.6 ac. of land is identified on the PUD plan a Neighborhood Commercial area. This area is shown on the Preliminary Plan as "presently non-developable neighborhood commercial", and the application states that the area is be designated as an area subject to future subdivision review. All of the lots will be served by the existing central water supply system that presently has 320,000 gallon storage tank and will have a 150,000 gallon storage tank added at a future date. The applicants state that there will the fire flows will exceed 500 gpm for the entire project. All of the lots are to utilize individual sewage disposal systems (ISDS), except the commercial lot located adjacent to CR I14. At this time the commercial lot will not be subdivided and will not be developed until central sewage disposal is available to the lot, Primary access to the area will be from the extension of the existing private road, Los Amigos Drive, and then there are seven shorter cul-de-sacs accessing a number of the proposed lots. Los Amigos drive will be extended almost three miles further back along the ridge. The cul-de-sacs and loop roads range in length just over 500 ft. to over 3,000 ft. in length.. There are proposed emergency access easements to adjoining fields, offof some of the longer cul-de-sacs and loops. REYIEW AGENCY COMMENTS 1. Division of Water Resources: The Division noted that the proposed water supply appears to be adequate, and injury to decreed water rights will not occur, as long as the water company operates pursuant to the decreed water rights and plan for III. .-' 2OL 2. J. 4. 5. 6. 7. augmentation-which are leased from the Los Amigos Ranch Parbrership. (See letterpes.+jJ3_) Colorado Department of Public Health and Environment: The department has not responded within the 21 days allowed by statute, therefore the CDPIIE is deemed to have approved the method of sewage disposal proposed for the subdivision. Roaring Fork School District RE-l: The District has previously determined that the proposed school site is adequate to meet the land requirerqpnts for a school site, as opposed to paying cash in lieu of land. (See letter pg. ,* ) Division of Wildlife: The DOW previously acknowledged that the development has tried to design around deer and elk ranges, but there is need to recognize that there are other types of wildlife impacts. Suggestions were made regarding methods for dealing with other types of wildlife. It qv recommend predefined building envelopes for certain lots. (See letter pgs.616 Carbondale & Rural Fire Protection District: The District states that portions of the development are in the Glenwood Springs Fire District and other areas are in no district. They recommend that the overlapping boundaries be resolved to allow the Carbondale District to protect the entire project and those portions not in any district be annexed to the District. They also recommended that the fire hydrant spacing be modified, which has been agreed to by the developer's representative. The District in a previous letter noted that they will be requiring the developers to pay impact fees directly to the District, at the time of platting lots. (See letter pg./ZaA Bureau of Land Management: The BLM expressed some concems about the potential for use conllicts between the public and private land. They have also noted the needto consider big game movement through the development. There are federal minerals underlying portions of the developmgnt, that need to be considered in any future subdivision action. (See letter pgs. /7 ) Colorado State Forest Service: An agency representative previously went on site with a local fire department representative and the applicant's representative and concluded that the proposed development can be protected from wildfire. A number of recommendations were made in a prior letter regarding the site improvements, ridge line setbacks and construction materials for structures. tncluded with the lefter were the NFPA 299 standards for the Protection of the Life and Property from Wildfire. A subsequent letter stated thatthe previous comments are still valid. (See letters and attachments pgs. eO -;l)b-)' Wright Water Engineers. tnc.: WWE was hired by the County to assist in the review of the Los Amigos Ranch Preliminary Plan. They noted a number of issues that 8. -'3- needed to be resolved before the County approved the previous Preliminary plan proposal for Filings 5A-11.. A number of issues were identified related to the water supply system, wastewater, drainage, roads, geologic hazards and some details in the plans that needto be clarified or corrected. (See letterpgs. frt' 2q ) WWE has reviewed the new application for Filings 6-10 and notid a number of issues related to the lots removed from the previous application, the rural lots, drainage and the use of ISDS for all of the lots. These comments will be incomorated into the other staff comments included in this staffreport. (See letter pgs. -3u3q ) ry. A. Zoning: The Los Amigos PUD zone district text and PUD Plan were amended by ResolutionNo. 96-34. As a condition of approval for the amendments, the applicant was required to dedicate at least the equival ent of 25Yo of each subdivision tothe Los Amigos homeowners association. Filings 6-10 is a total of 1703.058 ac. in size, with 970.708 ac. (56%) of Open Space. Filing 6 includes lots that had been previously designated "presently non-developable single-family residential" and an area designated "piesently non-developable neighborhood commercial". . It will be necessary to either merge the non- developable residential lots into some of the proposed lots or to amend the pUD to merge the lots with the Open Space. The PUD amendment can be accomplished by requesting approval of minor amendment to the PUD Plan. The non-developabll neighborhood commercial needs to be plaffed as separate lot in the fust final plat and has a plat note stating "the lot will not be developed until a preliminary plan and finalplat for the fi.rther subdivision of the lot is approved ty the Board of County Commissioners.,' B. Comprehensive Plan Compliance: The 1995 Garfield County Comprehensive plan identifies the Los Amigos PUD as an existing subdivision. and the plID was found to be in general conformity with the Comprehensive Plan when it was amended in 1996. C. Soils/Topography: The applicant's geologic report for this portion of the development "did not identifu any geologic conditions or potential geologic hazards that would prevent development of the site for the intended single familyiesidential use. We recommend we perform detailed soils and foundation investigations on a site specific basis to determine subsurface conditions and provide foundation recommendations." Consistent with this recommendation, the Board of County Commissioners required that the following plat note be placed on all subsequent plats, as a part of the pIlD amendment approved: --y - D. "Prior to the issuance of a building permit, the owner of each lot shall prepare and submit a soils and foundation report, a grading and drainage plan, and a geologically acceptable building site prepared and certified by a professional engineer. All improvements shall be constructed in accordance with such engineering recorrmendations, which shall be a condition of Los Amigos Ranch Architectural Control Committee approval and the building permit." WWE engineers noted in their letter, that RR Lot 3 appears to have a very limited building lot area, based upon the geologic report. After further discussion with the applicant, it was agreed that the final plat for RR Lot 3 will include a building envelope designated by registered professional geotechnical engineer and a plat note requiring the submittal of foundation design stamped by a professional geotechnical engineer with the building permit application. Road/Access: The proposed subdivision is accessed by Los Amigos Drive, which is being built to minor collector standards and will handle up to 250 single family dwellings. The applicants have proposed to build Los Amigos Drive as a minor collector with a 60 ft. row and 12 ft. driving lanes, up to Station 143+15.38. The rest of Los Amigos Drive will be built to Secondary Access standard with a 60 ft. ROW, with 1i ft. driving lanes. All other roads will be built to Rural Access standards with a 50 ft. ROW and 11 ft. wide driving lanes. All of the roads will have a chip and seal surface. All roads need to have names assigned to them, that are not used elsewhere in the County. Staffsuggests that the applicants not use "cedar" or "pinion" for any of the proposed streets names. Fire Protection: The Carbondale and Rural Fire Department reviewed the project and stated that the proposed amount of water appeared to be adequate and that the roads were adequately sized to accommodate emergency services equipment. The District had asked previously that the fire hydrant spacing be reduced to 500 ft. to comply with the Uniform Fire Code standards. The revised application was reviewed by the Fire District and hydrant spacing was agreed to by the developer. Any final plat application should include a letter from the District approving the hydrant spacing. It was also noted that a portion of the development is located in the Glenwood Springs Rural Fire Protection district. This section is located on the north end of the development and is only accessible from CR 114, [t has been proposed to deannex the portion of the in the Glenwood district and annex it to the Carbondale district. Water: As a part of the PUD amendment approval, the applicant was required to set forth the method of transferring the legal ownership and control of the water E. F. G. distribution facilities and water rights to the Los Amigos Homeowners Association. An agreement was submitted and approved by the Board of County Commissioners at the time of Final Plat approval of Filing 5 All new lots will have to be included in the same homeowners association. WWE has noted that RR Lots 1-4 are proposed to have individual wells for the sotuce of domestic water. They expressed concern about the use of wells for RR Lots 1-3, given the history of wells in the area and the proposed use of ISDS by the lots above the lots. They recommend that the " developer hetp facilitate the shortest connection possible to the central water system with easements". Staffconcurs with the recommendation and would add that the issue needs to be resolved prior to the approval of a Preliminary Plan by the Board of county commissioners. Wastewater: The residential lots in the application are proposed to use individual sewage disposal system (ISDS). Section 492 requires that "evidence of the result of soil percolation tests and produce excavations to determine maximum seasonal ground water level and depth to bedrock shall be provided". Additionally, the ptID resolution of approval contained the following condition of approval: 5. The (44) lots along "Road A" (.os Amigos Drive to the water tank) which could potentially drain into the Spring Valley Aquifer, all lots along Los Amigos Drive that currently lie within the Spring Valley Sanitation District, all lots depicted upon the puD plan as "High Density,' single family lots, and all lots depicted upon the PUD Plan as "Multi-Family" units shall be serviced by central sewer provided by the Spring Valley Sanitation District. Given the economic inefficiencies and impracticalities associated with extending and maintaining central sewer service to the remaining westerly single family lots in the P[ID, Applicant shall be allowed to service said remaining lots with individual sewage disposal systems (ISDS), subject to the roltowing conditions: (A) Applicant shall provide to the Board all information neederd by the Board to review the environmental and health impacts presented by ISDS service, which shall also be forwarded to the Colorado Department of Health, Water Quality Control Division for their review and recommendation. (B) The Board finds that the Colorado Department of Health has made a favorable recommendation regarding the proposed method of sewage disposal as required by C.R.S. 30-28-136(l)(g). The analysis provided for the review of the environmental and health impacts presented in the application did not provide any calculable basis for determ-ining potential downstream water quality impact. After discussions with the applicant and -6 F. his engineers, additional information was submitted for review by wwE. wwE noted that the additional analysis is based "upon existing data and reasonable engineering assumptions". They further state that the u"t*l conditions may vary significantly from the assumptions and it would be prudent to require the apilicant to implement a long term water quality monitoringprogram. Staff concurs that a monitoring progrirm would be appropriate, particularly given the recent presentations about the potential contamination of the Roaring Fork River by ammonia, due to non-point sources, such as individual sewage disposal systems. This is an issue that has been brought to the fore front in recent weeks and needs to be addressed. Staff recofilmends that the applicant be required to develop a proposed water quality management plan prior to the public hearing before the Board of County commissioners, that can be reviewed and found to be acceptable by wwE. Additionally, the applicant needs to propose the method of mitigatilg *y .rbr"quent water quality impacts, should the monitoring establish that the Los Amigos development is contributing to any water quality degradation identified as a result of the monitoring. Road Impacts: The applicant was required to make certain improvements to the intersection of the subdivision's main entrance and County Road t 14 and to pay a road impact fee at the time of final plat. The impact fee is to be based on the most current analysis of the cost of improvements to 114 from the Auburn Ridge apartments road intersection to Highway 82 and an analysis of the proportionate share of those expenses attributed to the Los Amigos PUD for those road improvements. The only study available dealing with those specific parameters, isthe analysis submitted by the applicant's engineer at the euo afprovat. The subsequent analysis done by the County used a different basis for establishing and cannot be used to establish a road impact fee for this pUD. The pUD apfroval established a $200/lot road impact fee for this development. Drainage: WWE noted that the application had noted some minor increase the amount of surface runofffrom the project, but had not proposed any mitigation for the increases. The applicants have reviewed the issue again and recommended on site detention of the surface runoffin certain drainages. Th... is no calculation of the amount of detention :uea is required, based upon calculations. The subdivision regulations require the calculation of the runoffand inclusion of the calculations in the application. WWE noted that the proposed locations appear to be correct, but there is a need for the calculations prior to the submittal of u n"a plat. Stafffeels that the calculations need to be provided to and accepted as being correct by WWE prior to the approval of the Preliminary Plan by the Board of County Commissioners. G. G.PUD Requirements : The applicant was required to include the following plat notes on any final plat: 1. Prior to the issuance of a building permit, the owner of each lot shall prepare and submit a soils and foundation report, a grading and drainage plan, and a geologically acceptable building site prepared and certified by a professional engineer. All improvements shall be constructed in accordance with such engineering recommendations, which shall be a condition of Los Amigos Ranch Architectural Control Committee approval and the building permit. 2. The owner of each lot utilizing an individual sewage disposal system (ISDS) shall obtain site specific percolation tests to determine whether a standard septic system is acceptable or an engineered system is appropriate or required. Each ISDS shall be designed to minimize tree removal and changes to the natural contours of the land. 3. The recommendations of the Colorado State Forester and the Fire Chief as set forth in the Supplemental Declarations dated September 28,1992 et. seq. shall be followed in the construction of all structures. 4. All lots designated to lie within the Spring Valley Sanitation District shall obtain central sewer service pursuant to agreement with the District. 5. Open hearth solid-fuel buming fireplaces are not allowed. 6. Each dwelling unit is allowed one dog. Subdivision/Phasing: Section 4:34 of the Garfield County Subdivision Regulations states that Preliminary Plan "approval shall be valid for a period not to exceed one (1) year from the date of Board approval, or conditional approval, unless an extension of not more that one (1) year is granted by the Board prior to the expiration ofthe period of approval..... Developments of over one hundred (100) lots may be phased over a period of time not to exceed fifteen (15) years. Any phasing must be approved by the Board at Preliminary Plan." The applicants phasing plan approved as a part of modified PIID required the submission of a Preliminary Plan for Phase 2, which is the remainder of the PUD, less the High Density single family area, by l2l3ll99. The present application meets that part of the phasing plan, but it represents an acceleration of the plan, which has created some problems with the subdivision regulation requirements. The proposed subdivision phasing plan for the submittal of a Final Plat does not appear to be consistent with the one year validity period for a Preliminary Plan. The proposed phasing plan states that the "completion of development per subdivision H. '-$ - III. improvement agreements" will occur by 1213112002. The previously noted language in Section 4:34 of the Subdivision Regulations requires the submission of a final plat within one (1) of Preliminary Plan approval. The Phasing Plan needs to be tied to the submission of a Final Plat within one (1) year of the approval of the Preliminary Plan. The applicant appears to be relying more on the outside phasing of the PUD, which may conflict with the Subdivision requirements. There needs to be new phasing plan submitted that complies with Section 4:34 ofthe Garfield Count Subdivision Regulations. As noted previously the fi.lther subdivision of the non-developable neighborhood commercial in Filing 6, needs to be noted on the plat in terms of the intent to divide further and only after the submittal and approval of a preliminary plan prior to the submittal of a new plat. RECOMMENDED FINDINGS: That the proper publication, public notice and posting were provided as required by law for the hearing before the Planning Commission; and That the hearing before the Planning Commission was extensive and complete, that all pertinent facts, matters and issues were submitted and that all interested parties were heard at that hearing; and C. That the proposed subdivision of land is in general compliance with the recommendations set forth in the Comprehensive Plan for the unincorporated area of the County; and That the proposed subdivision of land conforms to the Garfield County Zonrng Resolution; and That all data, surveys, analysis, studies, plans and designs as are required by the State of Colorado, and Garfield County, have been submitted and, in addition, have been found to meet all requirements of the Garfield County Subdivision Regulations. RECOMMEI\DATION The Planning Commission recommend approval ofthe proposed Los Amigos Ranch , Filings 6-10, subject to the following conditions: A. B. D. E. IV. o/- --/ 1.All representations of the applicant, either within the application or stated at the public hearings before the Planning Commission shall be considered conditions of approval unless otherwise stated by the Planning Commission. The Homeowner's Association shall be included as a part of the Los Amigos HOA and incorporated into it in accordance with the Colorado Revised Statutes. The protective covenants, articles of incorporation and other Homeowner's Association documents including by-laws will be submitted for review by the County Attomey prior to the approval of the Final Plat. The applicant shall pay $200 per lot in Road Impact Fees prior to the approval of the Final Plat. Priorto the approval ofthe Preliminary Plan by the Board of County Commissioners, the applicant shall provide documentation from the Glenwood Springs and Rural Fire Protection District approving the interior road design and fire protection plan prior to the submittal of a Final Plat or a letter stating that the District will accept the deannexation of the properfy in their district, subject to it being annexed into the Carbondale and Rural Fire Protection District. All recommendations of the Colorado State Forest Service regarding wildfue protection will be incorporated into the covenants, including the design guidelines identified in the NFPA 299 standards for the Protection of the Life and Property from Wildfire. That the residential lots in Filing No. 6, designated as "presently non-developable single family" lots will either be merged with adjoining lots in the filing or a request for minor amendment to the PUD Plan will be made to merge the lots in question with the open Space designation in the PUD. The lot shown as',presently non- developable neighborhood commercial" will be included on the Filing 6 final plat and noted as a lot subject for fi.rther subdivision and that no development will occur on the lot until a Preliminary Plan for the lot is submitted and approved by the Board of County Commissioners. That RR Lots 1-3 shall include easements for water and access purposes that are the shortest connection possible, on the applicable plat. Further that RR Lot 3 shall have a building envelope designated on the appropriate plat, that has been identified as being buildable by a registered geotechnical engineer. That prior to the approval of the Board of County Commissioners of the Preliminary Plan for Los Amigos Filings 6-10, the applicant shall develop a ground water quality monitoring plan and mitigation plan, to be reviewed and recommended for approval by the County's consulting engineer. 2. J. 4. 5. 7. 8. 9.That prior to the approval of the preliminary plan by the Board of County Commissioners, the applicant will submit to the County, the calculations for the projected surface runofffrom the project. The proposed design ofthe detention ponds shall be based upon the calculations. The applicant is required to include the following plat notes on any final plat: 1.Prior to the issuance of a building permit, the owner of each lot shall prepare and submit a soils and foundation report, a grading and drainage plan, and a geologically acceptable building site prepared and certified by a professional engineer. All improvements shall be constructed in accordance with such engineering recommendations, which shall be a condition of Los Amigos Ranch Architectural control committee approval and the building permit. The owner of each lot utilizing an individual sewage disposal system (ISDS) shall obtain site specific percolation tests to determine whether a standard septic system is acceptable or an engineered system is appropriate or required. Each ISDS shall be designed to minimize tree removal and changes to the natural contours of the land. The recommendations of the Colorado State Forester and the Fire Chief as set forth in the Supplemental Declarations dated September 28,1992 et. seq. shall be followed in the construction of all structures. All lots designated to lie within the Spring Valley Sanitation District shall obtain central sewer service pursuant to agreement with the District. Open hearth solid-fuel buming fireplaces are not allowed. Each dwelling unit is allowed one dog. That a new phasing plan, consistent with Section 4:34 of the Garfield County Subdivision Regulations, be submitted and accepted by the Board of County Commissioners prior to preliminary plan approval -ll 10. 2. 3. 4. 5. 6. STAIE Or COLOIUDO OTFICE OF THE STATE ENCTNEER Division of Water Resources Department of Natural Resources 1313 Sherman Street, Room 818 Denver, Colorado 80203 Phone (303) 866-3581 FAX (303) 866-3s89 February 18, 1998 Roy Romer Cowmor lames S. Lochhead Executive Direclor Hal D. Simpson State EngineerMr. Mark Bean Garfield County Planning Department 109 8th Street, Suite 303 Glenwood Springs, CO 81601 RE:Los Amigos Ranch PUD, Filings 6, 7, 8, I &10 Sections 5 & 6, T7S, R88W, 6th P.M. Sections 31 & 32, TOS, R88W, 6th P.M. Sections 35 & 36, TOS, R89W, 6th P.M. Water Division 5, Water District 38 Dear Mr. Bean: We have reviewed the subject preliminary plan, which proposes to create a total of 168 single-family dwellings on727 .13 acres located in filings 6 through 10. The proposed water supply is to be provided through a central system operated by the Red Canyon Water Company (Company). A letter of commitment from the Company, dated February 9, 1996, was included in the submittal material. We previously commented on a proposal which included the subject development in our letter of January 26, 1998. The only difference between the submittals appears to be that Filing 5A has been omitted and that portions of Filings 10 and 1 t have been included in Filing 6 as open space and presently non-developable parcels. The net effect has been a reduction of single-family dwellings by ten and elimination of the commercial development. Therefore, our previous comments still apply, and are repeated below. A letter from Mr. Loyal E- Leavenworth, Cated November 24, 1997, indicated that to date final plat approvals within the Los Amigos Ranch PUD totals 47 single family lots and 96 multi- family units. This proposal results in a total of 321 units. At full buildout, the PUD is projected to include a total of 327 single-family homes and 96 apartments. Total annual water demand at buildout will be 194 acre-feet, and consumptive use will be approximately 68 acre-feet. The 68 acre-feet of depletions are to be augmented pursuant to a plan for augmentation, which was approved by the Division 5 Water Court in case no. 87CW155. The PUD is cunently supplied by two wells, known as the Rancho Los Amigos Well No. 6 (permit no. 40906-F) and the Los Amigos Ranch Well No. 5 (permit no. 18147). Well No. 6 is decreed in Division 5 Water Court case nos. W-3873, W-3893, and 94CW36 for 300 gallons per minute for municipal use. Well No. 5 is decreed in case no. W-2156 for 300 gallons per minute for municipal, commercial, domestic and industrial uses. The water rights used to supply this PUD are owned by the Los Amigos Ranch Partnership, are leased to the Company for a period of 50 years with a 49-year renewal option. J/T A report dated November 17, 1997, prepared by Schmueser Gordon Meyer, tnc., indicated that Well No. 5 had been test pumped at 110 gallons per minute, and Well No. O had been test pumped at 400 gallons per minute. The combined yield of the two wells exceeds the estimated required peak day pumping rate at buildout of 335 galtons per minute. \ Pursuant to Section 30-28-136(1)(hxl), C.R.S., the proposed water supply appears adequate, and injury to decreed water rights will not occur, as long as the Company operates pursuant to the decreed water rights and plan for augmentation, which are leased from the Los Amigos Ranch Partnership. Should you have further questions or @mments regarding the water supply for this project, please contact Craig Lis at this office. Sincerely, Mr. Mark Bean February 18, 1998 SPUCMULos Amigos Ranch Flag 6-1O.doc Orlyn Bell, Division Engineer Joe Bergquist, Water Commissioner page 2 Steve Lautenschlager Assistant State Engineer - /5- [vru\ltlu I-vl\t\ gvllvvL ulJl rnA NU. V lUU.{CVaqU \{;.: Mark Bearr Garticld County Planning Department 109 8th Street, Suite 303 Glcnwood Springs, CO 81601 llc: Los Amigoe Rrnch - Filings 6 through l0 f)ear Mark: Los Amigos Ranch ltas included a l3 acre schoot site in its plan. This mccts thc District's rcquircmcnts for land dedicatiou for a subdivision of this size. Tlrank you for thc opportunity to provide cotnments on this preliminary plan. Pleasc tlon't ltcsitatc to call if you have any questions. Shannon Pclland Financc Dircctor W - /4- vv. vv tul . ""+reibphone (e70) ?19:9s.9;'*, Fcbruary 23. l99t STATE OF COLORADO Roy Romer, Goveraor DEPARTMENT OF NATT]RAL RESOT]RCES DIVISION OF WILDLIFE AN EQUAL OPPORTI.JNITY EMPLOYER John Mumma, Dircctor 6060 Broadwav Denvcr. Colorado 8o216 Telephone: (3O3) 297 - | 192 50633 Highway 6 &?4 Glenwood Springs, CO El6Ot 303-945-7228 oAffi€LrJ L,-ji-::ri ForlVildlfe- For Peopb January 5, 1998 Mark Bean Garfield County Planning Deparrnent 109 8th Streer, Suite 303 Glenwood Springs, CO 81601 RE: Comments on Los Amigos Ranch, Filings 5A-11 Dear Mark, While Los Amigos Ranch has gone a long way in trymg to avoid severe deer and elk winter ranges in their development, the Division of Wildtife would like o make some recommendations to Ery and improve the ability of homeowners to enjoy wildlife on their property, help avoid human/wildlife conflicts and help migration of wildlife onto severe winter ranges reserved by t os Amigos Ranch. First, the wildlife statement, irrcluded in the development plan by Greg Boecker gives a general list of the wildlife located on or near the development. It would be helpful to all new owners of this property for Los Amigos Rarch or the developer o provide a small brochure or leafler advising what wildlife species may be encountered and how to avoid potential wildlife related problems. Many owners moving into the area may not be aware of the possibility of coyotes killlng pets, bears searching out food inside vehicles and building, 66rrntain lion sightirgs in areas where their children may be playurg and damage to ornamentals by deer and elk. An informed owner has the abiliry to avoid or reduce these problems. Secondly, while this rurch is considered as less than ideal bear habitat and density of bears is considered low, bear proof garbage containers should be required. Carelessly handled trash auracts wildlife problems. Those species of wildlife generally considered least desirable when near housing (bears, skunks, coyotes and racoors) are aEacted to trash. Population densities of these species usually increase r#[sn fuutrrens do a poor job of trash management. Third, the Los Amigo Rarch Plan states that any ferrces built will be less than 42 irrches tall and will rcI define a propeny boundary but onty used o fence a building envelope. To facilitate the flow of alt wildlife throqh this property, we recorlmend that several los have buildirs ervelopes defined before approvd. These building envelopes should avoid crossing draws deer and elk may use to reach severe winrcr range. We recommerd that los on opposhe sides of a draw have building envelopes that leave as much of the draw open as possible. Predeftned building envelops are recomrnended for the following loa: . /t- DEPARTMENT OF NATURAL RESOURCES. Iemcr l.ochhcrd. Exccutivc Ditcsor WILDLIFE COMMISSION, Arnold Salazar. Ch:irrnen o Rcbcccr Frrr*, Vicc Chrirnun o Mrrk lrVrllcy, Sccr?rry Rcv. Icssc t-. Boyd. Jr., Mcmbcr o lemcs R. [.ong, Mcmbcr o Cherlcr D. L-cwis. Mcrnbcr r lolrn S[rlp, Mcmbcr o [,ouir Switl, Mcotbcr January 5, 1998 Page2 Filing 6 - Lots 5, 6,7 ,9, 33 and 37. Filing 7 - Lots 34,36,38, 40, 42,43, M,47 and 48. Filing 8 - lots 9, 10, 11, 16, and 17. Fillng 9 - Lots 2,4,6,42,44 and 46. Thank you for the opporunity to comment. Sincerely,*ryv 4, Larry L.breen District Wildlife Manager -/0 -''' Garbondale & Rural Fire Protection District - 300 Meadorcod Ddve o 81623 9632491 963{569 February 18, 1998 rEB A 0 p9E GAI+€LO COI.0ITY Mark Bean Garfield County Planner 109 Eighth Street, Suite 303 Glenwood Springs, CO 81601 RE: Los Amigos Ranch PreliminarT Plan, Filing 6 Through Filing 10 Mark: I have reviewed the prelimrnary plan application for Los Amigos Ranch. There is very little change in the plan from the prwious submittal from a fire protection standpoint. I would offer the following comments. Annexation I met wrth Cneg Boecker to discuss annexation rnto the fire district. We have recommended that the developer petrtionthe Glenwood Springs Rural Fire Protection District (GSMPD) for exclusion of ther area that is currently within the development. The area excluded by the GSRFPD along with the areas outside either district could then be included into the Carbondale & Rural Fire Protection District. This should take place before the recording of final plats. Water Svstem I have met with Greg Boecker to review fire hydrant locations and spacing. We have agreed on a design that is appropriate for the development based upon the lot locations and density. Please call if you have any questions. Bill Gavette Fire Marshal cc: Crreg Boecker .2/'1 r (Darbondale ( & ,t\ Rural Fire Proteetion Distrlot 300 Meadorcod Drirn Carbondale, CO 81623 (970) 96+2€1 Fax (970) 963{s69 January 5, 1998 Mark Bean Garfield County Planner 109 Eighth Street, Suile 303 Glenwood Springs, CO 81601 RE: Los Amigos Ranch PreliminarT plan, Filings 5A-ll I have reviewed the preliminary plan application and have recently visited the site with Vince Urbina of the Colorado State Forest Service and Greg Boecker. I would offer the following comments. Fire Protection Jurisdiction The northern portion of filing 6 and the northern half of filing 7 currently fall outside the boundaries the Carbondale & Rural Fire Protection District and are not withln any fire protection district. I have discussed this wrth Crreg Boecker and have recommended that these areas be annexed into the fire district prior through the petition process prior to final plat. F,ling 8 with the exception of lots 2,3 and4 and all of filing 9 appear to be wrthin the boundaries of the Glenwood Springs Fire Protection District. Two likely scenarios exist for providing service to these areas. One would be for the Carbondale & Rural Fire District to providi servicelhrough an agreement with the Glenwood Springs Fire Protection District. The other would require the transfer of legal jursdiction between the two distrias ttrough an exchsior/inclusion process. Representatives of the two districts are scheduled to meet and discuss this issue. Access The road layout is essentially unchange from the sketch plan. Access throughout the subdivision appears to be adequate. Water SuPplies The proposed water system generally appears to be adequate for the development.I would recommend that the fire hydrant spacing be reduced to 500 feet in accordancl with APPENDIX III-B of the Uniform Fire Code. Impact Fees The development is subject to impact fees adopted by the District. Fees are subject to penodic rwiew by the distria. Fees are based upon the per lot rmpact fee adopted by the Orsirict at the time of recording of final plat or at the time of execution of an agreement between the developer and the distria. Please call if you have any questions. |ry'"'ilt?(O -,'(nltzikHe,,Ul Bill Gavette Fire Marshal cc: Greg Boecker -/ g- United States Department of the Interior BUREAU OF LAND MANAGEMENT Glenwood Springs Resource Area 50629 Highway 6 and24 P.O. Box 1009 Glenwood Springs, Colorado 81602 IN REPLY REFER TO: January 5, 1998 Mr. Mark Bean Garfield Counry Planning Department 109 Sth Street - Suite 303 Glenwood Springs, Colorado 81601 Dear Mr. Bean: In response to your request for comments regarding the proposed Los Amigos Ranch, Filing 54-11 project, Ioffer the following statements for your scheduled January 14, 1998 planning commission review. I am attaching copies of previous correspondence pertaining to the Los Amigos Ranch puD. Although itappears that these filings do not abut public lands, *" *ould still anticipat" -thut u development of this magnitudewill create detrimental impacts. of specific concern to the BLM is the potential for increases in oHV use onadjacent public lands and the loss of big game winter range on private lands. The loss of habitat will force more animals onto the remaining public lands in the area, resulting in a decline inhabitat condition until the big game populations are reduced to where they are in balance with the availablehabitat' Again, we would like to point out the necessity of providing migratory corridors for big game animalsallowing movement between open space areas and other public and undeveloped private lands. under Colorado statutes, it is a landowner's responsibility to consrrucr, and maintain in good condition, a lawfulfence protecting their property in order to recover any damages from trespass livestock. we would also recommend for larger scale projects such as this one, that the developers/contractors be requiredto provide locations on-site for temporary camping facilities for those construction workers having no permanentresidence' We would also encourage the developirs and contractors to consider providing some tempoffyquarters on-site or at commercial facilities as a component of their compensation packag" fo. ,o*" of theirseasonal employees. We feel this is a reasonable mitigauon measure that would reduce crowding, trash,saniution and enfcrcement prcblems in public campgrounds anil orr disperserl camping areas on other publiclands. Thank you for the opportunity to comment. If there are any questions, please contact Leonard Coleman of thisoffice at 947-2814. Sincerely, Michael S. Mottice Area Manager 7/U.q_1 7/t-/4 -rffi'oi7Jl$01 Attachements ,?/?- Ci.1t^,*-Lurtlsi A. Vince Urbina Assistant District Forester Bill Gavette - Carbondale FPD Guy Meyer - Garfield County Sheriff's Office Greg Boecker ,rp1 5$$9& SERVTCE I .---/- State Servic$ Buildin! tl]l*reuo@LrNTYc*"1'r'":;:*:Hi*T#li January 29, 1 998 _- Telephone: (970) 24&7325 Mark Bean Garfield County Planning Department 109 8th Street, Suite 303 Glenwood Springs, CO 81601 Re; Los Amigos Ranch, Filing 6-10 Wildfire Hazard Review Mark, I received this new preliminary plan from your office on January 28th. Because it appeared to be very similar to the original application that I reviewed, I called your office to find out what had changed from the previous application. Stella informed me that there had been some water problems and that the overall development had been downsized. After our discussion I could see there was no need to change my comments addressed in the original letter of December 13, 1997. Therefore, I stand by my recommendations of that first letter dated December 31, 1997. This application did reference Exhibit E6 as having more information on wildfire issues. This exhibit was not included in either of my documents. I would like to have if for my files if that is possible. Please feel free to call me with any questions. Sincerely, CC: *Z/O- ffiil 0,a tsYd GfiiFi€t0 COUNry state services Building December 31, 1gg7 GLAFF}€LI) Mark Bean Garfield County Planning Department 109 8th Street, Suite 303 Glenwood Springs, CO 81601 Re: Los Amigos Ranch, Filing 5A-1 1 Wildfire Hazard Review Mark, 222 S. 6th Streel Room 416 Grand Junction. Colorado 815O1 Telephone: (97O) 248-7325 I read through the application and visited the sitc r,vith G:'cg Boecker and Bill Gavette of the Carbondale Fire Department. As you know, it is a large development so I will limit my comments to generalities rather than specific lot recommendations. Access to the property is from County Road 1 14. The road into the older filings is a two-lane paved surface with drainage ditches on either side of the road that are mostly devoid of woody vegetation. lwas told that these roads meet the existing county standard. In the plan there are drawings of the proposed typical roads for the development. Los Amigos Drive, which services the majority of all filings, currently meets the National Fire Protection Association (NFPA) 299 standard for the Protection of Life and Property from Wildfire. The 299 standard calls for 12 foot lanes with 4 foot shoulders for a total traveled way of 32 foot. The fact that the drainage ditches are cleared of woody vegetation adds to the overall effectiveness of Los Amigos Drive as a fuel break and an escape route for local residents. lt would be a good idea to keep the woody vegetation out of these drainage swales. The cul-de-sacs are shown as coming on to Los Amigos Drive at a right angle. This is desirable for visibility and access. The 299 standard recommends a 50 foot radius for cul-de-sacs. The plans show a 45 foot cul-de-sac radius but it looks like there will also be a shoulder which doesn't appear to be counted in the overall measurement. The Carbondale Fire Department should have the final word on the proposed cul-de-sac diameters. The road drawing for the Rural Residential lots (r.e., Filing 8) does not show much detail. I recommend incorporating a turn around at the end of this access road for emergency service vehicles. We drove through the development on an existing farm road and several historical ranch roads. The main road and cul-de-sacs were staked and mowed to see where they will be put situated. I don't foresee any problems with steep grades. Greg did show us several existing and proposed "fire lanes". These all help with egress in the event of a catastrophic fire. All in all, the road system looks good. ? 7 /- LOS AMIGOS. PAGE 2A high percentage of the lots are situated along the southwest edge of a bench above Highway 82. This bench is not visible from the highway. The slopes leading up to this bench are steep and support primarily pinyon/juniper trees with little to no vegetation(i.e., grass, forbes and shrubs) in the under story. These pinyon/juniper stands would be rated as a severe wildfire hazard by Colorado State Forest Service (CSFS) standards because of the slope steepness and density of the conifers. For this reason, I recommend that all structures be situated a minimum of 5O feet from the ridge line (see enclosed NFPA 299 Figure 3-2.4d. Greg had already intended to require this stipulation before lmentioned anything about the potential problem, because he understands the potentially dangerous situation. The existing vegetation on these lots can be grass, sage and pinyonijuniper in various combinations. Most grassy lots would be rated as a low wildfire hazard. Sage/grass lots can be a low to medium hazard. Lots that are better than half conifer would be a severe wildfire hazard. Even though there are some lots rated as severe, the fact that these lots are not on steep slopes and we are dealing with pinyon/juniper vegetation leads me to believe that the wildfire hazard can be readily mitigated by incorporating defensible space principles. My wildfire mitigation recommendations are as follows. 7)For a distance of 10 feet around all structures establish and maintain vegetation at 6 inches or less (i.e., mowed lawn). No woody vegetation should be allowed to remain within this perimeter, either from existing stands or proposed landscaping. ln addition, flammable materials should not be stored in this zone. 2) For a minimum distance of 30 feet around all structures thin existing trees so that the edges of tree crowns are no closer than 1O feet at maturity. As the slope percentage increases the minimum defensible space distance will increase (see enclosed chart). For example, homes on 1Oo/o slopes should have a minimum defensible space distance of 35 feet uphill and to the sides, and 37 feet downhill. Homes on 2Qa/o slopes need a minimum of 4O feet uphill and to the sides, and 47 feet downhill. ln addition, the lower branches should be pruned off to eliminate ladder fuels which can allow a fire to burn from ground level to lower tree branches. These branches should be removed up to half the total height or 10 f eet whichever is least. When removing trees as part of the defensible space process, try to leave a mix ofyoung and old trees (i.e., unevenaged stand). An unevenaged forest is healthier than an evenaged forest. 3/ All dead wood within 100 f eet of structures should be removed. Greg mentioned that non-combustible roofing material would be required. That's agood idea. Feel free to call me with any questions about my comments. S-incglely, [t_1\,^/u\- IJJ\-/w-.* A. Vince Urbina Assistant District Forester Bill Gavette - Carbondale FD Guy Meyer - Garfield County Sheriff's Office Greg Boecker cc: 27-- Water Engineers, lnc. 818 Colorado Ave. P.O. Box 219 Glenwood Springs. Cotorado g 1602 19701 945-77ss rEL 1970) 945-92t0 FAX {303) 893-r 608 DENVER D|RECT UNE January 9, 1998 Mark Bean Garfield County Planning Office Regulatory Office & Personnel 109 Eighth Street, Suite 303 Glenwood Springs, Colorado 81601-3303 RE: Los Amigos Ranch - Preliminary plat Review Dear Mark: At the request of Garfield County, Wright Water Engineers, Inc. (WWE) has reviewed thepreliminary plat submittal for Los Amigos Ranch Filings 54 through 11 dated November 26, 1997 prepared by Schmueser Gordon Meyer. In addition, we reviewed the preliminary plan Application notebook dated November 20, 1997 . The following presents are coilrments on water supply, wastewater, drainage, roads, geological hazards, and miscellaneous design details. SUMMARY From a technical standpoint, the preliminary plan submittal is generally in conformance with County regulations and standard of practice for engineering design. However, there are a few major concerns such as adequacy of the proposed sewage disposal system and several minor items that should be resolved, addressed, and/or revised as app.opriaie prior to approval or as part of an approval of the submittal. WATER STJPPLY The quantity calculations for in-house water supply is based on 80 gallons per day per person and 3.5 people per single-family residence. For planning purposes, 100 gallons per person per day is typically used. In addition, larger homes which include guest residences or "in-law" residences will often house up to 5 or 5.5 people per day. Acrual water usage could be more than what was estimated. The preliminary plan application report states rhat the water supply will be chlorinated and a 30-minute contact time will be achieved through 460 feet of a24- inch line. This 30-minute contact time will be met as long as the rotal flow from the chlorination building is less than 370 gallons per minute. DURA TGO 19701 259-74t tDEI.JVER l J0ll,r80. r i00 /7v EOU|DER . t3A3l 473-9500 Mark Bean Garfield Counry Planning Office January 9, 1998 Page 2 o Well No. 6 should be located and shown on the Master Water plan Sheet. o We recofirmend the water line minimum depth of cover be at least six feet, andpreferably seven feet, rather than the 5.5 feei proposed. o The minimum operating pressure on the design analysis for the water system is 20psi. This is low for a single-family residenCe and will require boostei pumps forindividual lots. The water system analysis includes water service for the four rural lots; however,service line connections to these lots, especially to Lots 2, 3, and 4 would eitherrequire a separate easement through the adjacent single-family lots or a very longservice line. We recommend easements be added to adjaient lots that would accommodate the shortest route for water service lines to serve these four rural lots. The storage tank sizing appears to be adequate for the proposed population. o We understand that the Carbondale & Rural Fire Protection District will bereviewing the drawings and the hydraulic computations for fue flow requirements, hydrant spacing, cul-de-sac lengths, and the hydrant detail. In some cases, thehydrant spacing appears to be in excess of the proposed 800-foot spacing that is discussed in the report. WASTEWATER o The typical trench section shows the depth of cover to be 5.5 feet. This will probably be acceptable for sewer lines with steep slopes. The profiles on Sheets S1 through 54, however, show areas where cover is less than 5.5 feet and should be adjusted to maintain the minimum cover. o Twenty-one exploratory test pits were excavated to evaluate the subzurface conditions. In many of the exploratory pits, practical refusal was encountered at less than six feet due to a hard, dense rock formation. Percolation tests were performed adjacent to some of the pits and percolation rates were within acceptable ranges. However, according to County standards, areas with bedrock less than eight leet deep require a mound or other engineered system. Based on the rezuls and locations of the test pits, this appears to be the case for the majoriry of the lots. Site specific analyses will determine the rype of sysrem for each lot. -?+- Mark Bean Garfield County Planning Office January 9, 1998 Page 3 Easements should be provided for sewer mains that are outside of the road right-of-way. For example, Lots 40,3, and 5 on Drawing 51, Lots 1 and 52 on Drawing 52, and Lot 1 on Drawing 54. BOCC Resolution No. 96-34 requires central sewer for certain lots and allows ISDSfor the remaining lots subject to the applicant submitting an analysis of environmental and health impacts for review by the BOCC and the C-olorado Deparunent of Health. We did not find such an analysis in the submittal. Resolution No. 96-34 also conditions use of ISDS on a favorable recommendation from the state regarding the proposed method of sewage disposal. The existing Spring Valley Sanitation District (SVSD) wastewater treatrnent plant has a permitted capacity of 52,000 gpd. Data presented in the submittal show that existing development sewer demands total 51,840 gpd and there is no existing capaciry to serve the proposed Filings 5A through 11. The approved Site Application for the proposed expansion of the SVSD treatrnent faciliry to serve an additional 110,000 gpd expires February 26, lggg. It is our understanding that plans and specifications for the expansion have not been submitted to the State and the approval will likely expire. The Site Application approval dated February 26, 1997 required the svsD, in accordance with State policy, to develop a service area to include all existing and future development adjacent to existing sewer service (Item 6). It is our understanding that this requirement was appealed due to financial hardship. This provision of the site Application approval was subsequently removed. The SVSD stated in a letter dated November 25, lgg7 that the District can and will serve those portions of the Los Amigos submittal proposed for central sewer. However, until the District obtains a Discharge to Groundwater Permit (i.e., demonstrates that the existing facility is operating in compliance with applicable standards) and obtains approval for the design plans and specifications and a Discharge to Groundwater Permit for the proposed expansion (and new site application if existing approval expires), we do nor believe the District can demonstrate the ability ro serye the proposed project. DRAINAGE o The drainage calculations reference 18 drainage elements. However, they iue not identified or labeled on any of the drawings. '75- Mark Bean Garfield Counry Planning Office January 9, 1998 Page 4 The culvert sizings are all based on inlet control which is acceptable. However, amaximum headwater to depth ratio should be held at 1.5. This may affect culvertsize. Drainage Elements No. 15 and 1g both appear to be undersized. The impervious coverage used for the drainage calculations assumes a building footprint, including driveways and garages, of 3,500 square-feet. Based on existing development, we believe this should be closer to 5,000 to 7,000 square-feet. Subdivision Regulation Section 9:43 sutes that "new developments, where they create runoff in excess of historic levels, detention ditches and ponds may be required to retain up to the 100-year stonn. " Existing conditions foi ttris site were not calculated so there is no analytical comparison as to whether or not there are downstream impacts from this development. We recommend that this analysis be conducted to determine if detention is required. Due to the concentration of flows in areas that may be highly erodible, we recommend the use of BMPs to minimize the impacts of erosion due to development. In areas where culverts are proposed under the new roads, we recommend the following. First, culvert outlets should be protected with riprap. This is especially important on the steeper culverts. Secondly, we recorlmend that the discharge be directed into a drainage easement which will carry flows along the property lines or into existing swales. In areas where there are no existing swales,-the flow should be re-disbursed so as to minimize the impacts of concentrated flow which could cause erosion below the property. The ditch sizing calculations should be revised to reflect the following items. First, channels with slopes that are steep enough to create critical depth shoutO be sized for critical depth and not for super-critical depth. Secondly, velocity should be considered and appropriate channel linings andior energy dissipation included in the design. The Drainage Master Plan Sheet LAD and the Drainage Element Worksheer in the calculations do not correlate at all locations. For example, the culverts for basins 6, 8, and 10 are not shown. The plan is missing several culverts that are noted in the calculations and also includes several culverts that are not noted in the calculations. These should be corrected to match each other and flows and culvert sizes verified. " 26- Mark Bean Garfield County Planning Office January 9, 1998 Page 5 a ROADS There are several culverts located at low points in the roadway, but are not located in the swale centerline of the topography immediately adjacent to the road. These should be re-evaluated to ensure that flows will reach the culvert. Two examples include a culvert located at Station 47 +10 on [os Amigos Drive and a culvert located on West Road at Station 36+90. The side slopes used to size the roadside ditches are all atZ L However, this does not match the typical ditches shown on the road cross sections. This should be resolved. There is a worksheet for a circular channel flow in the calculations. However, it is not clear what this pertains to. The major swales shown on the drawings should be evaluated for depth of flow relative to the proposed building sites immediately adjacent to it. Drainage easements should be added where applicable. The entire subdivision is served by a single road access off of County Road 114. We recommend adding a second access road. Road B is shown with a vehicle trips per day of 230 which would put it in the category of secondary access versus rural access as proposed in the submittal. The cross-section used for the rural access shows a 2-foot distance between the shoulder and the center of the flow line of the adjacent ditch. However, counry regulations require 6-foot minimum ditch width which would make this dimension 3 feet. o There are several radii that are less than those noted in the county regulatioru. o There are several stretches of road that exceed 8 percent grades as noted report. However, we did not see any that were over 10 percent, which maximum allowed in the Counry Regulations. o There are at least five cul-de-sacs that exceed the 600-foot lengXh and several dead- ends. This exceeds the County's standards for cul{e-sacs and dead-end streets. in the is the z' z7- Mark Bean Garfield County Planning Office January 9, 1998 Page 6 There are several intersections off of Los Amigos Road that occur on tight curves. Sight distances should be addressed. Access to rural l-ot 4 is not defined on the drawings. Responsibility and design standards for constnrction of the access to rural Lots I ,2, atd,3 should be clarified and defined. A cost estimate analysis for repair of County Road 114 was prepared by Schmueser Gordon Meyer in April 1996. The estimate appears to be reasonable for the stated assumptions. This estimate is for a one-time cost and should, ideally, be done after construction of improvements are complete. However, with the proposed extended phasing, intermittent repair work could be needed which is not included in the cost anaiysis. The submittal states that a left-turn lane was constructed at County Road 114 and Los Amigos Road. As constructed drawings should be submiued for review. GEOLOGICAL HAZARDS There are several hazard areas noted in the submitted reports. One is a landslide area and the others are a series of faults. The report recommends that building sites not be located near these areas. We recommend the faults and the landslide areas be shown on the site plan, including any recommended setbacks for proposed buildings. The landslide areas (two are noted in the Lincoln-DeVore report) are discussed as being fairly stable. However, there is a possibility that the proposed culverts will concentrate surface runoff and affect the drainage in these gullies which could, inturn' affect the stability. We suggest that this scenario be reviewed by the geotechnical engineers. The stability of these areas are of concern, especially where they leave the project site and could potentially effect neighboring properti;s. The Lincoln-DeVore report references the palisades topography and recommeuds that setbacks be required from any of the palisade formations. This information should be identified and transferred to a site plan with appropriate setbacks shown. The soils report, done by Hepworth-Pawlak, identifies a Basalt formation which in many locations is within 6 feet of the ground surface. This may affect the ability to install a standard ISDS system. Mark Bean Garfield County Planning Office January 9, 1998 Page 7 DETAILS Revise water/sewer crossing to include crossings with new sewer. Service line details should show property lines. The water service should include a marker post. Recommend bedding under the base of standard manholes. Hydrant placement note should be revised since there is no curb and gutter on this project. Also need to label depth of bury (or cover). Label side slopes and/or width of drainage outlet swale. L,abel pavement sections (i.e., depths of materials, etc.) of road sections. Please call if you have any questions or need additional information. Very truly yours, WRTGHT WATER ENGINEERS, INC. PMB/MJE/dIf 921-M7.U0 Peggy M. Bailey, P.E. Senior Water Resources Mi -7?- Water Engineers, lnc. 818 Colorado Ave. P.O. 8ox 219 Glenwood Springs. Cotorado 81602 l97ol 945-7755 TEL 19701 945-9210 FM (3031 893-r608 DENVER DtRECI',UNE March 4, L998 Mark Bean Garfield County Plenning Office Regulatory Office & Personnel 109 Eighth Srreer, Suite 303 Glenwood Springs, Colorado 81601-3303 RE: Los Amigos Ranch - Preliminary Plat Review Drainage Submittal Dear Mark: At the request of Garfield Counry, Wright V/ater Engineers, Inc. flMWE) has reviewed the revised preliminary plat submittal for Los Amigos Ranch, Filings 6 through 10 dated February 9, 1998. The revised zubmittal generally differs from the original zubmittal in that it eliminate5 the proposed lots that would have been served by the Spring Valley Sanitation District and responds to the issues raised in review of the original zubmittal. SIIVIMARY In general, the revised submittal addresses the concerns noted in the our January 9, 1998 letter. There were, however, several items still unresolved that were discussed at a meeting with County staff on February 13, 1998. A meeting was scheduled with the applicant on February 24, 1998 with Dean Gordon and David Kou of Schmueser Gordon Meyer; Greg Boecker, owner's representative; Michael Erion and Peggy Bailey; and Mark Bean. At this 6ggting, w€ discussed several unresolved iszues which are noted below. The plat still shows lots in the Spring Valley Sanitation District, but includes a note saying that they are "not developable." We discussed if this would be acceptable to the Counry. It was suggested at the meeting that these lots be merged with the adjacent lots rather than noting them as being undevelopable. This seemed to be acceptable to the applicant. There appears to be some unresolved iszues regarding fire protection jurisdictional areas. [n particular, the applicant must annex a portion of the site into the Carbondale Rural and Fire Protection District and, secondly, there is an area that is within the Glenwood Springs Fire Protection District. We understand that it is the applicant's intent to have the entire site within the Carbondale Rural and Fire Prorcction District t. ) AJRA JCO t9701 259-741t'-fu-DENVE,? rl0ll .l8Gr 700 8our-oER - t3031 473-95co Mark Bean Garfield County Planning Office March 4, 1998 Page 2 J. 4. prior to final plat. At this 6ggting, a letter was zubmitted from the fire deparhent stating that the road design and hydrant spacing of the project is acceptabi" to th" Carbondale Rural and Fire Protection District. If Glenwood Springs Fire Protection District seryes a portion of the project, they should also commint on the project. The effects of development otr drainage has still not been completely addressed. The applicant stated in their resubmittal that post-develop flows will increase but, the amount is negligible. It was our recorlmendation that the applicant address the impacts of these increased flows on off-site conveyance facilities such as channels and culverts. A follow up zubminal was made on February 27, lggS addressing drainage related iszues and is discussed later in this report. We discussed rural lot 3 in that most of the lot is covered by either landslide area or fault lines. Our recommendation was to require a building envelope for this lot because it appears that not much of the lot is available for development. The applicant, however, feels that it is possible to construct a home on the landslide area based on work that has been performed by their geotechnical engineers. Mark Bean zuggested that they include some language about development of this lot requiring a geotechnical engineer to review and sign off on the location of any proposed stmctures. We discussed access and utilities for rural lots I through 3 and made the point that the access and utility corridor for lots 2 arfi 3 is very long. Dean stated that this is not a technical issue and should not be of our concern. However, we believe that wells are a poor choice for these rural lots given the history of wells in this area and given the number of ISDS system that will be installed in this area. Therefore, it is our recommendation that the developer help facilitate the shortest connection possible to the central water system with easements. We discussed the requirement of BOCC Resolution No. 96-34 requesting an analysis of environmental and health impacts which has not been submitted. In particular, we were interested in seeing a mass balance analysis tracing the migration of nitrates and, in particular, a discussion should be made regarding the impact these ISDS systems will have on existing wells adjacent to the project. This has been addressed in a subsequent subminal dated March 3, 1998 and is addressed later in this report. 5. 6. o 3r Mark Bean Garfield County planning Off,rce March 4, 1998 Page 3 DRAINAGE Schmueser Gordon Meyer submitted a letter report dated February ZT,lgggaddressing drainageissues related to the development of Los Amigos Ranch. This letter is in response to ogrrecommendation that an analysis be conducted to evaluate the impacts of development on runoffat and below the project site. of particular concern is the dbwnstream drainage facilities,including open channels and culverts, that may be impacted by increased flows from thisdevelopment. The Schmueser Gordon Meyer letter report proposes the use of on-site detention ponds for maintaining historic flow rates under developed conditions. The drawing LAD, Drainage MasterPlan, was modified to include six detention ponds located in four orainige [35ins, all wittrin theproperry boundaries of Los Amigos. The letter report commits to performing drainagecalculations and fiml design of the detention facilities ai the final design. In summary, we believe that the proposed concept of on-site detention ponds as shown on the revised Drainage Master Plan will meet County criteria and wiil address the particular concernsof impacts to off-site culverts and channels. County Subdivision Rigulations require computations of expected flows and design of the proposed facilities at pretiminary zubmittal. The letter report did not include any computations. Ho*er.r, the concept appears reasonable and can likely be implemented as shown with relatively few modifications at the final submittal. The responsibiiities for maintenance of the ponds need to be specified. In reviewing this zubminal, wwE performed a field inspection of the facilities downstream of the noted design points and the Los Amigos properry. Our f,reld investigation is summarized asfollows: 1. Drainage Basin 2 is the largest basin and appears to contain much of the Los Amigos properry. Runoff drains off of Los Amigos properry through an open channel and into a 60-inch CMP under Highway 82. The op"n channel betnreen the Los Amigos properry and the culvert is approximately 1,500 feet long. It is a poorly defined channel with a scattering of large boulders characteristic of a debrisflow fan. There are several homes on this debris fan. The 60-inch culvert includes a headwall and is clean with no sediment or trash in the pipe. WWE believes that the most serious concern about drainage Basin 2 is -the potential impacts on this debris flow fan. Schmueser Gordon Meyer is proposing two detention ponds in this basin ro maintain historic flow rates under developed conditions. These ponds are located above the steep canyon area and on the flaner portions of the project site. ?1k Mark Bean Garfield County Planning Off,rce March 4, 1998 Page 4 Drainage Basin 3 drains to a 24-inch culvert that crosses under County Road 114.This culvert is in very poor condition with the end sections having been severelydamaged. In addition, this culvert discharges down below County Road 114 to anarea that is currently under construction and shows no sign of an existing or trewdminage ditch to convey flows away from this 24-inch culvert. This culveft hasno direct impact to the Los Amigos development. However, it is important thatexisting flows be maintained under developed conditions due to the downsrre2m conditions. Drainage Basin 4 is tributary to an lS-inch diameter CMP also draining under Counry Road 114. We were unable to locate the inlet to this pipe, but tie outletis visible from the road. Flows exit the culvert and drop ri timt 5 to 10 feetbefore hitting the ground and flow tfuough a man-made ditch which traverses through a hayfield. It is unlikely that development or increased flows from the development will have any negative impact 6l dlninage in this area. However, dueto the potential erosion from the "drop" outlet at the lg-inch culvert, we recommend they implement rhe design of the detendon pond as shown. Basin 1 drains through a24-nchCMP under the frontage road parallel to Highway82. This culvert also drains a poorly defined ctrannet with evidence of debrisflows. We recommend that they proceed with design of the detention pond as shown. We recommend that Los Amigos proceed with the final design of their proposed detentionfacilities as shown on the revised Drainage Master Plan. Tne Oralnag" i{r.,., plan showsseveral ponds in the upper reaches of the drainage basins. The final design should include acheck to see that there is sufficient drainage area flowing to these pondi to create enoughdetention volume that is needed for maintaining historic flow rates. There are also severaldetention basins shown within private lots. Therefore, final design should include the appropriate easements for deenrion, access, and maintenance. ISDS IIEALTH AI.ID ENVIRONMENT ANALYSIS We received a lener repon to Greg Boecker from Resource Engineering dated March 3, l99g rysardin8 ISDS impaca. This report is in response to the requiremenr in tt" BOCC ResolutionNo. 96-34 Condirion of Approval No. 5(A). 2. 3. 4. - 33- Mark Bean Garfield County Planning Office March 4, 1998 Page 5 The Resource Fngineering report indicates that there is no impact to the Spring Valley aquifer and it is highly unlikely that the Los Amigos ISDS systems will contaminate the groundwater and wells in the Roaring Fork Valley. This analysis is based on available data and reasonable engineering assr:mptions. However, if actual conditions vary significantly from the assumptions, the potential impacts may be more or tgss rhan identified ir, tn. anaiy5i5. In addition, thecumulative imFact of groundwater with a nitrate level of 4 mgll diluted in the Roaring Forkvalley groundwater may be siguificaut if the existing nitrate concentrations are high. Theiefore, we recommend that the applicant develop a baseline and long-tenn water quality monitoring planprior to final plat. The plan should include a threshold limit or trigger it which mitigatlon ofpotential impacts would be reErired. If you have any questions or wish to discuss this in detail, please feel free to call. Very tnrly yours, WRIGHT WATER ENGINEERS, INC. PMB/MJE/dIf v21447.040 Senior Water Resources Engineer Michael - 3+-