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HomeMy WebLinkAbout5.0 Staff Report BOCC 04.13.98"X/- "il +, jB,' REQUEST: BOCC PROJECT INT'ORMATION AI\[D STAFF COMMENTS 4n3t98 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 APPLICANT: ENGIITIEERS: LOCATION: SITE DATA: WATER: SEWER: ACCESS: ZOMNG: I.RELATIONSHIP TO TIIE COMPREHENSIVE 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 1981 and 1996. DESCRIPTION OF TIIE PROPOSAL l II. -f- A.Site Description: The properfy 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 4o/o to over 90o/o. The steeper slopes have vegetation consisting primarily of pinion/jturiper 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. Project Description: The proposed subdivision includes five (5) separate filings of the approved Los Amigos PLID. Filings 6-10 consist of 168 single family lotspn-q total of 1703.058 ac. of land, of which975.927 ac. is open Space. There u..@gr\ 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 remainng4.6 ac. of land is identified on the PIID 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 114. 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. REVIEW AGENCY COMMENTS 1. Division of Water Resources: The Division noted that the proposed water supply appears to be adequate, and uUury to decreed water rights will not occur, as long as the water company operates pursuant to the decreed water rights and plan for augrnentatioq which are leased from the Los Amigos Ranch Partnership. (See letterpi'.lst t4 ) B. III. -) t-6 2. 4. 5. 6. 7. Colorado Department of Public Health and Environment: The department has not responded within the2l 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 requirements for a school site, as opposed to paying cash in lieu of land. (See letter pg. 15 ) 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. . They recommend predefined building envelopes for certain lots. (See letter pgs/L-/ 8) 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./?+J0) Bureau of Land Management: The BLM expressed some concerns about the potential for use conflicts between the public and private land. They have also noted the need to consider big game movement through the development. There are federal minerals underlying portions of the development, that need to be considered in any future subdivision action. (See letter pgs. Jl ; 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 wildfue. A number of recommendations were made in a prior letter regarding the site improvements, ridge line setbacks and construction materials for structures. Included with the letter were the NFPA 299 standards for the Protection of the Life and Propertv from Wildfire. A subsequent letter stated that the previous comments are still valid. (See letters and attachments pgs. JaC Y I Wright Water Engineers.lnc.: 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 needed to be resolved before the County approved the previous Preliminary Plan proposal for Filings 5A-1 1.. A number of issues were identified related to the water supply system, wastewater, drainage, roads, geologic hazards and some details in the 8. -3' plans that need to be clarified or corrected. (See letter pgs. J5- f / ) WWE has reviewed the new application for Filings 6-10 and noted 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 were incorporated into the other staff comments included in this staff report. (See letter pgs. ,r?'3L ) Since the Planning Commission meeting, WWE and the applicant's engineers have had a number of discussions and produced some additional documentation to deal with the drainage and ISDS impact issues. Enclosed is a lettgr summarizing the WWE response to the applicant's proposals. (See pgs. -*_3_81 ry. MAJOR ISSIIES AI\{D CONCERNS A. Zontng: The Los Amigos PUD zone district text and PUD Plan were amended by Resolution No. 96-34. As a condition of approval for the amendments, the applicant was required to dedicate at least the equivalent of 25Yo of each subdivision to the 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 "presently 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 PLID Plan. The non-developable neighborhood commercial needs to be platted 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 final plat for the further subdivision of the lot is approved by the Board of County Commissioners." Comprehensive Plan Compliance: The 1995 Garfield County Comprehensive Plan identifies the Los Amigos PUD as an existing subdivision. and the PI-ID was found to be in general conformity with the Comprehensive Plan when it was amended in 1996. 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 family residential 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 recorlmendation, the Board of County Commissioners required that the following plat note be placed on all subsequent plats, as a part of the PUD amendment approved: B. C. 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 recorlmendations, 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 arrd 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 11 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, It has been proposed to deannex the portion of the in the Glenwood district and annex it to the Carbondale district. E. -5- G. 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 distribution facilities and water.ights 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 source of domestic water. They expressed concem 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 help 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 4.92 requies 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 PUD resolution of approval contained the following condition of approval: 5. The (44) lots along "Road A" (Los Amigos Drive to the water tank) which could potentially drain into the Spring Valley Aquifer, all lots along Los Amigos Drive that curently lie within the Spring Valley Sanitation District, all lots depicted upon the PIID Plan as "High Densit;r" single family lots, and all lots depicted upon the PLID Plan as "Multi-Family" units shall be serviced by central sewer provided by the Spring Valley Sanitation District. Qv-eq_tb_e, economic inefficiencigs and impracticalities associated with exlen_ding and mafitairiing cintrai iewEr seivicelo the remaining weiterly single A-ity tots i-r the PIID, Applicant shall be allowed to service said remaining lo.tq wlth individual sewage disposal systems (ISDS), subject to the following ' (A) Applicant shall provide to the Board all information needed 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(1)(g). -b' F. F. The first analysis provided for the review of the environmental and health impacts presented in the application did not provide any calculable basis for determining potential downstream water quality impact. After discussions with the applicant and 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 actual conditions may vary significantly from the assumptions and it would be prudent to require the applicant to implement a long term water quality monitoring program. Qtatr*a the Planning Commission concurred that a monitoring program would be appropriate, particularly gi".; the recent presentations about thg pqtential contamination of the Roaring Fork Ri,_u.__t by ammonia, due to non-point sources, such as individual sewage disposal sYslenis) p-e applicant proposed to submit further information at the Planning Commidsion meeting that would either support the need for an improved design of the ISD systems proposed for the development or..a proposed mitigation plan for potential contamination of the down gradient wells.r The applicant submitted the enclosed report to the County, which WWE used as''a basis for the previously noted letter. WWE agreed with the assumptions and calculations in the report and will be recommending some additional comments regarding the design standards and maintenance plan at the hearing. Road Impacts: The applicant was required to make certain improvements to the intersection of the subdivision's main entrance and County Road 114 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 PIID for those road improvements. The only study available dealing with those specific parameters, is the analysis submitted by the applicant's engineer at the PIID approval. The subsequent analysis done by the Coturty used a different basis for establishing and cannot be used to establish a road impact fee for this PUD. The PIID approval established a S200/lot road impact fee for this development. Drainage: WWE noted that the application had noted some minor increase the amount of surface nurofffrom 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 runoff in certain drainages. llhere is no calculation of the amount of detention area is required, based upon calculations. The subdivision regulations require the calculation of the runoffand inclusion of the calculations in the application. WWE had noted that the proposed locations appear to be correct, but there is a need for the calculations prior to the submittal of a final plat. Additional calculations were submitted by the applicant and found to be acceptable by WWE. G. -1- G. PUD Requfuements : 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 burning 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 (i) 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 of the 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 P[ID, 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 H. proposed phasing plan states that the "completion of development per subdivision 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 neerds 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 of the Garfield Count Subdivision Regulations. As noted previously the further 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. III. RECOMMENDEDFINDINGS: C. That the proper publication, public notice and posting were provided as required by law for the hearing before the Board of County Commissioners; and That the hearing before the Board of County Commissioners was extensive and complete, that all pertinent facts, matters and issues were submitted and that all interested parties were heard at that hearing; and 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 Courty 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. A. B. D. E. -?- ry. RECOMMENDATION The Planning Commission recommended approval of the proposed Los Amigos Ranch , Filings 6-10, subject to the following conditions: 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. 2. The Homeowner's Association shall be included as a part of the Los Amigos HOA and incoqporated 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. 3. The applicant shall pay $200 per lot in Road Impact Fees prior to the approval of the Final Plat. the app and Rural Fire Protection District letter stating that the District ,the deannexation of the property in their district, subject to it being annexed into the and Rtual Fire Protection District. All recommendations of the Colorado State Forest Service regarding wildfre 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 PtrD. 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 a minor modification of the PLID Plan be approved by the Board of County Commissioners as a part of the approval of the Preliminary Plan. 4. 5. 6. the approval of the Preliminary Plan by the Board of documentation from "rg.,Se interior road design and fire protection plan or a 7.That RR Lots 1-3 shall include easements for water and access purposes that are the shortest connection possible consistent with sound environmental conditions and constraints, 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. Commissioners, the applicqnl shall develop a mdwater quality monitoring plan, or in the altemative, develop a new lon and recommended for approval The applicant is required to include the following plat notes on any final plat: 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 tee 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 burning fireplaces are not allowed. Each dwelling unit is allowed one dog. - ll- C water by th l. 2. 3- 4. 5. 6. That prior to the approval of the preliminary plan by the Board of County 8. 11. 12. 13. That a new phasing plan, consistent with Section 4:34 of the Garfreld County Subdivision Regulations, be submitted and accepted by the Board of county Commissioners prior to preliminary plan approval That the applicant comply with all of the recommendations of the Division of Wildlife noted in a letter dated 3llll98. At the time of each Final Plat, a properly formatted computer disks will be provided to the County that will transfer the plat information to the County Assessor's CAD system and the County Geographic Information System 1Dolt 0,t.1 L tDgrua ln-*^"o 4'g@'' l1 . 12. -fl- STATE OF COLOTUDO OITICE OF THE STATE ENGINEER Division of Water Resources Department of Natural Resources 1313 Sherman Street, Room 918 Denver, Colorado 80203 Phone (303) 866-3581 FAX (303) 865-3589 February 18, 1998 Mr. Mark Bean Garfield County Planning Department 109 8th Street, Suite 303 Glenwood Springs, CO 81601 RE:Los.Amigos Ranch PUD, Filings 6,7,8, 9 &10 Sections 5 & 6, T7S, R88W,6th P.M.' Sections 31 & 32, T65, R88W, 6th P.M. Sections 35 & 36, T65, 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 on 727 .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 11 have been included in Filing 6 as open space and presently nondevelopable 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, dated 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 augmentatjon, which was approved by the Division 5 Water Court in case no. 87CW155. The PUD is cunently supplied by fwo wells, known as the Rancho Los Amigos Well f.fo. 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 industnal uses. The water nghts 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 40-year renewal option. Roy Romer Govemor lames S. Lochhead Executive Oirector Hal D. Simpson State Enginee, ' /!t' Mr. Mark Bean February 18,1998 A report dated November 17,1997, prepared by Schmueser Gordon Meyer, lnc., indicated thatWell No.5 had been test pumped at 110 gallons perminute, and Well No.6 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 gallons per minute. \ Pursuant to Section 30-28-136(1XhXl), 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 ftom he 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, Steve Lautenschlager Assistant State Engineer SPUCMULoS Amigos Ranch Flag 6-1O.doc Odyn Bell, Division Engineer Joe Bergquist, Water Commissioner -/q- )ir Fcbrusry 23, 1998 Mark Bcan Garficld County Planuing Department 109 8th Strect, Suite 303 . Glcnwood Springs, CO 81601 Re: Lou Amigoa Rrnch - Filings 6 through l0 f)ear Mark: Los Amigos Ranch has included a l3 acrc school site in its plan. This mccts thc District's rcquircmcnls for land dcdication for a subdivision of this size. Thank you for thc opportunity to provide cornrnents on this preliminary plan. Pleaso tlon't hcsitatc to call if you lrave any questions. *wWq Financc Dircctor . ..5- .'r,i ..,:i.jr. rnil.t tm.f.L Sf*roaarnr-:.rrorl|AFroxsrAlt'irEm Oj*rrrmnr'' i... Sl{ANltOx:rEu^O)algpaafrcrpr -' /5- ..vtutlalY I v.... ,v..vYs y ay a STATE OF COLORADO Roy Romer, Governor DEPARTMENT OF NATI]RAL RESOURCES DIYISION OF WILDLIFE AN EQUAL OPPORTI,JNITY EMPLOYER Iohn Mumma, Dircctor 6O6O Broadwav Dcuvcr. Colorado E0216 Tclephone: (3O3) 297 -l 192 50633Highway6&24 Glcowood Springs, CO El6Ol 30.3-945-7228 e' tl UJ iltlr 0 5 lg?t OAff€LU rlL,..;J: ForWfunfe- Far Peopb January 5, 1998 Mark Bean Garfield County planning Department 109 8th Street, Suite 303 Glenwood Springs, CO 81601 RE: Comments on Los Amigos Ranch, Filings 5A-tl Deu Mark, While Los Amigos Ranch has gone a long way in Erymg to avoid severe deer and elk winter ranges in rheir developmed, the Division of Wildlife would like o make some recommendations o ury and improve the abiliry of homeowners to enjoy wildlife on their property, help avoid human/wildlife conflica and help migration of wildlife onto severe winter leng€S reserved by L-os Amigos Ranch. First, the wildlife statemefl iDcluded 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 [.os Amigos Rarrch or the developer to provide a small brochue or leaflet advising what wildlife species may be encountered and how to avoid potential wildlife relatd problems. Many owners moving ino the area IDay not be aware of the possibility of coyotes kiling pets, bears searching out food inside vehicles and building, mor:main lion sightings in areas where their children may be playrng and damage o ornamentals by deer and elk. An informed owner has the ability o avoid or reduce these problems. Secondly, wille ttris rarch is corsidered as less than ided bear habitat and density of bears is considered low, bear proof garbage conrainers should be required. Carelessly handled 6rsh atrracts wildlife probleur. Those species of wildlife generally considered least desirable when near horsing (bears, skilnlcs, coyots ard racoons) are artraoed ro trash. Popularion densities of these species usually increasc when humans do a poor job of uash management. Third, the Los Amigo Rarrh Plan sarcs that any ferrces built will be less trar 42 irrches tall and wil Dot define a properry boundary but only used o fence a building envelope. To facilitarc the flow of all wildlife ttrough tris properry, we recommerd that several lots have buil.ling erwelopes defurcd before approval. Thesc building envelopes should avoid crossing draws deer urd elk may usc to reach scvere winter pngc. We recommend that los on opposia sides of a draw tuve building envelopes that leave as much of the draw open as possible. Predefined building envelops are recornmended for the fotlowing loa: - /6- DEPARTMET{T OF NATIJR L RESOURCES. Jenrcr Lochhcrd. Excantivc Dircoor WILDLIFE COMMISSION, Arnold Srlezar, Chrirmu o Rcbccce Pnnt. Vicc Chrinnrn o Mrrt LrVrllcy, Sccrarry Rcv. Icssc t-. tloyrl. Jr.. Mcmbcr. Jrmo R. L,ong, Mcmbcr r Chrrlcr D. I-errrir. Mcmbcr r John Sollp, Mcnrbcr. Louir Swii. Mcdllcf January 5, 1998 Page2 Filing 6 - I-ots 5, 6, 7, 9, 33 and,37. Filttrg 7 - Lots 34,36,38, 40, 42,43, M,47 and 48. Fihng 8 - I-ots 9, 10, 11, 16, and 17. Filtng 9 - I.ots 2,4,6,42,44 and 46. Thank you for the opporumity to comment. Sincerely,*rys( 4,** Larry L.breen District Wildlife Manager -n- STATE OF COLORADO Roy Romer, Governor DEPARTMENT OF NATURAL RESOURCES DIVISION OF WILDLIFE AN EQUAL OPPORT1NITY EMPLOYER John Mumma, Director 6060 Broadway Denver, Colorado 80216 Telephone: (303) 297 -1192 50633Highway6&24 Glenwood Springs, CO E1601 303-945-'1228 For Wildltfe- For People March 11, 1998 Mark Bean Garfield Counry Planning Department 109 8th Street, Suite 303 Glenwood Springs, CO 81601 Comments on Los Amigos Ranch, Filings 5A-11 Dear Mark, Since my letter dated January 5, 1998, I have had a chance to discuss my recommendations with Greg Boecker. After reviewing a beuer map of the area, I have altered some of my recommendations. This leuer is a follow-up attempt to clariff some misundersumdings. Greg Boecker was concerned about what was meant by bear proof garbage containers. Certain companies build garbage containers with heavy duty lids and openings that Iook like a mailbox letter drop, however, other designs of containers that preclude bear entry are acceptable. Garages or small sheds with doors and windows closed are usually bear proof. If any trash is to be stored outside of an enclosed building, other than on the same day it is set out on the curb for pickup, bear proof containers should be required. I recommended that several lots have predefined building envelopes 0o preclude fencing of areas near draws that deer and elk would use to move to critical winter range. After reviewing a beuer map, I have dropped several of these lots from this list. However, there is still some confusion. Los Amigos covenants allow fences of less ttran forty-two inches to fence a building envelope but not a property boundary. p61 this reason, if no building envelope is required, a landowner may construe his building envelope to include all but a few feet from the property boundary. Due to the wording of Los Amigos covenants, I would still like tro recommend predefined building envelopes on the following lots: Filing6-Loa6and7. Filing 7 - Lots 34, 36, 38, 40,42,43,47 and 48. Filing 8 - Lots 9, 10 and 11. Filing 9 - Lots 2, 4 and 6. Thank you for the oppornrnity to comment. Singqrely, ^ ,L4 \X6t4l1 Cll**ts-1-' Larry L. @reen District lVitotire Manager -lt' DEPARTMENT OF NATURAL RESOURCES, James l.ochhead, Executive Director WILDLIFE COMMISSION, Arnold Salazar, Chairman o Rebecca Frank, Vice Chairman o Mark [,eValley, Secretary Bemard L. Black, Member . James R. Long, Member o Charles D. kwis, Member . louis Swift, Member l,tAR t a 1e9&, Garbondale & Rural Fire Protection Distrlct - February 18, 1998 G^I+i€LO CO(SITY Mark Bean Garfield County Planner 109 Eighth Street, Suite 303 Glenwood Springs, CO 81601 RE: Los Amigos Ranch Preliminary Ptan, Filing 6 Through Filing l0 Mark: I have reviewed the prelimrnary plan application for Los Amigos Ranch. There is very little change in the plan from the prorious submittal from a fire protection standpornt. I would offer the following comments. Annexation I met wrth Crreg Boecker to discuss annexation into the fire district. We have recommended that the developer petition the Glenwood Springs Rural Fire Protection District (GSRFPD) for exclusion of their area that s currently within the development. The area excluded by the GSRFPD along with the areas outside either distna could then be rncluded into the Carbondale & Rural Fire Protection District. Ths should take place before the recording of final plats. Water Svstem I have met with Crreg 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. BillGavette Fire lvfarshal cc: Creg Boecker 300 Meadoruaod Drivc -l?- ffiBe0p98 | ('- Carbondale & Rural Fire Protection Distrlet - 300 illeariotrood Dlnru Carbondale, CO &6An (970) 9632.191 Fax (970) 963{5e January 5, 1998 Mark Bean Garfield County Planner 109 Eighth Street, Suite 303 Glenwood Springs, CO 81601 RE: Los Amigos Ranch Preliminary Plan, Filings 5A-11 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 fiting 7 currently fall outside the boundaries the Carbondale & Rural Fire Protection District and are not withrn any fire protection district. I have discussed this with Greg Boecker and have recommended that these areas be anno(ed into the fire district prior through the petition process prior to final plat. Fiiing 8 with the exception of lots 2,3 and 4 and all of filing 9 appear to be within the boundaries of the Glenwood Springs Fire Protection Distnct. Two likely scenarios exist for providing sewice to these areas. One would be for the Carbondale & Rural Fire District to provide service through an agreement with the Glenwood Springs Fire kotection District. The other would require the transfer of legal jurisdiaion between the two distrias ttrough an exchsion/inchsion process. Representatives of the turo districts are scheduled to meet and discuss ths ssue. Access The road layout is essentially unchange from the sketch plan. Access throughout the subdivision appears to be adequate. Water Supplies The proposed water systern generally appean to be adequate for the development. I would recommend that the fire hydrant spacing be reduced to 500 feet in accordance with APPEI{DIX III-B of the Uniform Fre Code. Imoact Fees The development is subject to impact fees adopted by the Distnct. Fees are subject to penodic rwiewby the distria. Fees are based upon the per lot rmpact fee adopted by the District at the time of recording of final plat or at the time of execution of an agreement between the developer and the district. Please call if you have any questions. BruM Biil Gaverte Fire Vlarshal cc: Greg Boecker -;la- a United States Department of the Interior BUREAU OF LAND MANAGEMENT Clenwood Springs Resource Area 50629 Highway 6 and 24 P.O. Box l0O9 Glenwood Springs, Colorado 81602 January 5, 1998 Mr. Mark Bean Garfield County 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 5A-11 project, I offer the following s[atements for your scheduled January 14, 1998 planning commission review. I am attaching copies of previous correspondence pertaining to the Los Amigos Ranch PUD. Although it appears that these filings do not abut public lands, we would still anticipate that a development of this magnitude will create detrimental impacts. Of specihc concern to the BLM is the potential for increases in OIfV use on adjacent public lands and the loss of big game winter range on private lands. The loss of habitat will force more animals onto the remaining pubiic lands in the area resulting in a decline in habitat condition until the big game populauons are reduced to where they are in balance with the available habitat. Again, we would like to point out the necessity of providing migratory corridors for big game animals allowing movement between open space areas and other public and undeveloped private lands. Under Colorado statutes, it is a landowner's responsibility to construct, and maintain in good condition, a lawful fence protecting their property in order to recover any damages from trespass livestock. We would also recommend for larger scale projecs such as this one, that the developers/contractors be requircd to provide locations on-site for temporary camping facilitres for those construction workers having no permanent residence. We would also encourage the developers and contractors to consider providing some temporary quarters on-site or at commercial facilities as a component of their compensation package for some of their seasonal employees. We feel this is a reasonable mitigation measure that would reduce crowding, trash, saniedon and enfcrcement prcblems in public campgrounds and on dispersed camping areas on other public lands. Thank you for the opportuniry to comment. If there are any questions, pleasc contact Leonard Coleman of this office at 947-2814. Sincerely, IN REPLY REFER TO 7rud-l 7//"/4 Michael S. Mottice Area Manager Attachements -21 - t\'LL*-Lu,tf,**l A. Vince Urbina Assistant District Forester cc:Bill Gavette - Carbondale FPD Guy Meyer - Garfield County Sheriff's Office Greg Boecker t - State Servlces Building Eilm*.ocoLhrrYc-"'f i"*":*:ffiffi r,,,i * Telephone (970) 24*7325 SER\[CE January 29, 1 998 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 28tn. 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, 13tN 5 t 1998 Sf 0,atg,Eg qA#iELD cou'JTY state services Building December 31, 1997 qiuTiELt) Mark Bean Garfield County Planning Department 109 8th Street, Suite 303 Glenwood Springs, CO 81601 Re: Los Amigos Ranch, Filing 5A-11 Wildfire Hazard Review 222 S.6th Street Room 416 Grand Junction. Colorado 81501 Telephone: (97O) 24&7325 Mark, ! read through the application and visited the sitc w'ith Grcg 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. I was told that these roads meet the existing county standard. ln 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 tor 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 agpear 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 Bural 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. ? 73- LOS AMIGOS - PAGE 2 A 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 3-2.4b). Greg had already intended to require this stipulation before I mentioned anything about the potential problem, because he understands the potentially dangerous situation. The existing vegetation on these lots can be grass, sage and pinyon/juniper in various combinations. Most grassy lots would be rated as a low wildfire hazard. Sage/grass lots can be a tow 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. 1) For a distance of 1O 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 10 feet at maturity. As the slope percentage increases the minimum defensible space distance will increase (see enclosed chart). For example, homes on 1Oolo slopes should have a minimum defensible space distance of 35 feet uphill and to the sides, and 37 feet downhill. Homes on 2Oo/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 of young and old trees (i.e., unevenaged stand). An unevenaged forest is healthier than an evenaged forest. 3/ All dead wood within 100 feet of structures should be removed. Greg mentioned that non-combustible roofing material would be required. That's a good idea. Feel free to call me with any questions about my Comments. Sincglely, A. Vince Urbina Assistant District Forester Bill Gavette - Carbondale FD Guy Meyer - Garfield CountY Sheriff's Office Greg Boecker CC: 2.'{ - Water Engineers, lnc. SlSColoradoAve. P.O. Box 219 Glenwood Springs. Colorado 81602 19701e45-7755 reL 1970l, 945-92t0 FPX {3031 893-t 608 DENVER DIRECT 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 - plgliminary Plat Review Dear Mark: At the request of Garfield County, Wright Water Engineers, Inc. (WWE) has reviewed the preliminary plat submittal for Los Amigos Ranch Filings 5A through 11 dated November 26, i997 prepared by Schmueser Gordon Meyer. In addition, we reviewed the Preliminary Plan Application notebook dated November 20,1997. The following presents are comments on water supply, wastewater, drainage, roads, geological hazards, and miscellaneous design details. SUMMARY From a technical standpoint, the preliminary plan zubmittal is generally in conforrrance with Counry 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 appropriate prior to approval or as part of an approval of the subminal. WATER STIPPLY 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 that the water supply will be chlorinated and a 30-minute contact time will be achieved through 460 feet of aZS inch line. This 30-minure contact time will be met as long as the total flow from the chlorination building is less than 370 gallons per minute. DEtJvER Ii0ll,r80-r ;00 aJRA JGO t9701 259'7qt t/?r 8O{JrrER - 1303l. 471'9500 rri .. .r' Mark Bean Garfield County Planning Office January 9, 1998 Page 2 r Well No. 6 should be located and shown on the Master Water Plan Sheet. We recommend the water line minimum depth of cover be at least six feet, and preferably seven feet, rather than the 5.5 feet proposed. The minimum operating pressure on the design analysis for the water system is 20 psi. This is low for a single-family residence and will require booster pumps for individual 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 either require a separate easement through the adjacent single-family lots or a very long service line. We recommend easements be added to adjacent lsts that would accommodate the shonest route for water service lines to serve these four rural lots. o The storage tank sizing appears to be adequate for the proposed population. o We undersund that the Carbondale & Rural Fire Protection District will be reviewing the drawings and the hydraulic computations for flue flow requirements, hydrant spacing, cul-de-sac lengths, and the hydrant detail. In some cases, the hydrant 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 51 through 54, however, show areas where cover is less than 5.5 feet and should be adjusted to maintain the minimum cover. o Twenry-one exploratory test pits were excavated to evaluate the zubzurface 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 qrithin acceptable ranges. However, according to County standards, areas with bedrock less than eight feet deep require a mound or other engineered system. Based on the rezults and locations of the test pirs, rhis appears to be the case for the majoriry of the lots. Site specific analyses will determine the rype of system for each lot. -7b- Mark Bean Garfield County Planning Offrce January 9, 1998 Page 3 Easements should be provided for sewel 62ins 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 ISDS for the remaining lots subject to the applicant submitting an analysis of environrnental and health impacts for review by the BOCC and the Colorado Deparment 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 th9 proposed method of sewage disposal. The existing Spring Valley Sanitation District (SVSD) wastewater treatment 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 existrng capaciry to serye the proposed Filings 5A through 11. The approved Site Application for the proposed expansion of the SVSD treament faciliry to serve an additional 110,000 gpd expires February 26, L998. 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 25,1997 that the District can and will serye those portions of the Los Amigos zubminal proposed for central sewer. However, until the District obtains a Discharge to Groundwater Permit (i.e., demonstrates that the existing faciliry 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 not believe the District can demonstrate the abiliry to serve the proposed project. DRAINAGE o The drainage calculations reference 18 drainage elements. However, they are oot identified or labeled on any of the drawings. t/l ,- Mark Bean Garfield County Planning Office Ianuary 9, 1998 Page 4 The culvert sizings are all based on inlet control which is acceptable. However, a maximum headwater to depth ratio should be held at 1.5. This may affect culvert size. Drainage Elements No. 15 and 18 both appear to be undersized. The impervious coverage used for the drainage calcuiations 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 states 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 stoun. " Existing conditions for this 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 1tri5 enelysis 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 recolrmend the following. First, culvert outlets should be protected with riprap. This is especially important on the steeper culverts. Secondly, we recorrmend 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 properry. The ditch sizing calculations should be revised to reflect the following items. First, channels with slopes that are steep enough to create critical depth should be sized for critical depth and not for zuper-critical depth. Secondly, velociry should be considered and appropriate channel linings and"/or energy dissipation included in the design. The Drainage Master Plan Sheet LAD and the Drainage Element Worksheet in the calculatiors 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. - zg- rt Mark Bean Garfield County Planning Office January 9, 1998 Page 5 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 Los Amigos Drive and a culvert located on West Road at Station 36+90. The side slopes used to size the roadside ditches are all at?: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 ciicular 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 benreen the shoulder and the center of the flow line of the adjacent ditch. However, county regulations require 6-foot minimum ditch width which would make this dimension 3 feet. There are several radii that are less than those noted in the county regulations. There are several stretches of road that exceed 8 percent grades as noted in the report. However, we did not see any that were over 10 percent, which is the maximum allowed in the Counry Regulations. There are ar least five cul-de-sacs that exceed the 600-foot lengh and several dead- ends. This exceeds the Counry's standards for culde-sacs and dead<rd streets. '2 zT Mark Bean Garfield County Planning Office January 9, 1998 Page 6 There are several intersections off of Los Amigos Road thet occur on tight curves. Sight distances should be addressed. Access to rural Lot 4 is not defined on the drawings. Responsibility and design standards forconstructionof the access to rural Lots 1,2, and 3 shouldbe clarified and defined. A cost estimate analysis for repair of County Road 114 was prepared by Schmueser Gordon Meyer in April L996. 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, interminent repair work could be needed which is not included in the cost anaiysis. The submittal states that a left-turn lane was constnrcted at County Road 114 and Los Amigos Road. As constnrcted drawings should be submined for review. GEOLOGICAL IIAZARDS o 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. o 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 ttrese gullies which could, in turn, affect the stability. We suggest that this scenario be reviewed by the geotechnical engineers. The stability of these areas are of concern, especially wherc they leave the project site and could potentially effect neighboring properties. e The Lincoln-DeVore report references the palisades topography and recommends that serbacks be required from any of the palisade formations. This information should be idenrified and transferred to a site plan with appropriate setbacks shown. o The soils report, done by Hepworth-Pawlak, identifies a Basait formation which in many locations is within 6 feet of the ground surface. This may affect the abiliry to insull a standard ISDS system. -30 - Mark Bean Garfield County Planning Offrce January 9, 1998 Page 7 DETAILS Revise water/sewer crossing to include gles5ings 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. Hydraut 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. I-abel pavement sections (i.e., depths of materials, etc.) of road sections. Please call if you have any questions or need additional information. Very tnrly yours, WRIGIIT WATER ENGII\EERS, INC. PMB/MIE/dIf y2L-M7.W . -boJ ^rr. sq.rvJ , r Senior Water Resources Engineer Mi -31 . IEEE Wright Water Engineers, tnc. 818 ColoradoAve P.O. Box 219 Glenwood Spnngs. Cotorado 8 t602 (9701 945-7755 TEL (9701 945-921O FM [303] 893-r 608 DENVER DTREo, UNE March 4, L998 Mark Bean Garfield Couury Planning Offlrce Regulatory OfFrce & Personnel 109 Eighth Street, Suite 303 Glenwood Springs, Colorado 81601-3303 RE: Los Amigos Ranch - plgliminary plat Review Drainage submittal Dear Mark: At the request of Garfield Counry, Wright Water Engineers, Inc. (WWE) has reviewed the revised preliminery plat submittai for Los Amigos Ranch, Filings 6 through 10 dated February 9, 1998. The revised zubminal generally dffiers from the originat zubmittal in that it eliminates 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 zubminal. fl-TMMARY In general, the revised zubmittal addresses the concerns noted in the our January 9, 199g letter. There were, however, several items still unresolved that were discussed at a 6ssring with Counry staff on February 13, 1998. A meeting was scheduled with the applicant on Fe6nrary24, 1998 with Dean Gordon and David Kotz of Schmueser Gordon Miier; Greg Boeckei, owner's representative; Michael Erion and Peggy Bailey; and Mark Bean. At this 6ssring, we discussed several unresolved iszues which are noted below. 1. The plat still shows lots in the Spring Valley Sanitation District, but includes a notc saying that they are 'not developable. " We discussed if this would, be acceptable to the County. It was zuggesrcd at the meeting that these lots be merged with the adjacent lots rather thau noting them as being undevelopable. This seemed to bc acceptable to the applicant. ?- There appears to be some unresolved iszues regarding Fue protection jurisdictional areas. ln particular, the applicant must annex a portion of the site into the Carbondale Rural and Fire Protection District and, secondly, therc is an area that is wirhin the Glenwood Springs Fire Protection District. We understad rhar it is the applicant's intent to have the entire site within the Carbondale Rural and Fire Protection District DURATGO 19701 259-74t tDENVES /303t .r8Gt 700 -3?- EourDER - t3031 173,5no Mark Bean Garfield County Plenning Office March 4, 1998 Page 2 J. 4. prior to final plat. At this meering, a letter was zubmitted from the fue deparment stating that the road design and hydrant spacing of the project is acceptable to the Carbondale Rurai and Fire Protection District. If Glenwood Springs Fire Protection District serves a portion of the project, they should also comment on the project. The effects of developmetrt on dpinage has still not been completely addressed. The applicant stated in their resubmittal that postdevelop flows will increase but, the amount is negligible. It was our recommendatiou that the applicant address the impacts of these increased flows on off-site cooveyance facilities zuch as channels and culverts. A follow up zubminal was mede on February 27, 1998 addressing drainage related iszues aud 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 developmeil. The applicant, however, feels that it is possible to constmct a home on the landslide area based on work that has been performed by their geotechnisal engineers. Mark Bean suggested 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 strlrctures. We discussed access and utilities for rural lots I through 3 and made the point that the access and utiliry corridor for lots 2 and 3 is very long. Dean stated that this is not a technical issue and should not be of our concem. However, we believe that wells are a poor choice for ttrese 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 4a analySis of environmental and heaith impacts which hes se1 been submined. [n particular, we were inrerested in seeing a mass balance analysis racing the migration of nitrates and, in panicular, a discussion should be made regarding the impact these ISDS systeuui will have on exisring wells adjacent to the project. This has [ggn addressed in a subsequent zubminal dated March 3, 1998 and is addressed larer in this report. 5. 6. o3y Mark Bean Garfield County Planning Office March 4, 1998 Page 3 DRAINAGE Schmueser Gordon Meyer submitted a lener report dated February 27, L998 addressing drainage issues related to the development of Los Amigos Ranch. This letter is in response to our recommendation that xa aneiy5i5 be conducted to evaluate the impacu of development oo runoff at and below the project site. Of particular concern is the downstreem 6lainage facilities, including open channels and culverts, that may be impacted by increased flows from this development. The Schmueser Gordon Meyer lefter report proposes the use of on-site detention ponds for maintaining historic flow rates under developed conditions. The drawing LA,D, Drainage Master PIan, was modified to include six detention ponds located in four drainage [x5ins, all wirhin the properfy boundaries of Los Amigos. The letter report commits to performing drainage calculations and fiaal design of the detention facilities ar rhe fiml desigl. ln summary, we believe that the proposed concept of on-site derention ponds as shown on the revised Drainage Master Plan will meet County criteria and will address the particular concernsof impacts to off-site culverts and channels. Counry Subdivision Regulations require computations of expected flows and design of the proposed facilities at preliminary zubminal. The letter report did not include any computations. However, the concept appears reasonable and can likely be implemented as shown with relatively few modificarioDs at rhe finat submirtal. The responsibilities 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 field investigation is summarized as follows: 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 atr open channel and into a 60-inch CMP under Highway 82. The open channel between the Los Amigos properry and the culvert is approximarely 1,500 feet long. It is a poorly defined channel with a scattering of large boulders characteristic of a debris flow 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 locared above the steep canyon area and on the flatrcr portions of the project site. 12 1f Mark Bean Garfield County Ptanning Off,ice March 4, 1998 Page 4 Drainage Basin 3 drains to a 24-inch culvert that crosses under Counry Road 114. This culvert is in very poor condition with the end sections having been severely damaged. In addition, this culvert discharges down below Counry Road 114 to an area that is currently under constnrction and shows no sign of an sxi5ting or new drainage ditch to cotrvey flows away from this 24-inch culvert. This culvert has no direct impact to the Los Amigos development. However, it is important that existing flows be maintained under developed condirions due to the downstream conditions. Drainage Basin 4 is tributary to an 18-inch diameter CMP also draining under Counry Road 114. We were rrnable to locate the inlet to this pipe, but the outlet is visible from the road. Flows exit the culvert and drop at least 5 to 10 feet before hining the ground and flow through 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 on drainage in this area. However, dueto the potential erosion from the "drop" outlet at the l8-inch culveft, we recommend they implemenr the design of rhe detention pond as shown. Basin 1 drains through a 24-iuch CMP under the frontage road parallel to Highway 82. This culvert also drains a poorly defined channel with evidence of debris flows. We recommend that they proceed with design of the derention pond as shown. Vle recommend that Los Amigos proceed with the frnal design of their proposed detention facilities as shown on the revised Drainage Master Plan. The Drainage Master Plan shows several ponds in the upper reaches of the drainage basins. The final design should include a check to see that there is suff,rcient drainage area flowing to rhese ponds to create enough detention volume thar is needed for maintaining Nstoric flow rates. There are also several dercntion basins shown within private lots. Therefore, final design should include the appropriate easements for detention, access, and maintenance. ISDS MALTH fu\D ENYTRONMENT AT.{ALYSIS V/e received a lener repon to Greg Boecker from Resource Engineering dared March 3, 1998 rcgarding ISDS impacts. This report is in rcsponse to the requirement in the BOCC Resolution No. 96-34 Condition of Approval No. 5(A). 2. 3. 4. Mark Beau Garfield County Planning Office March 4, 1998 Page 5 The Resource Engineering report indicates that there is no impact to the Spring Valley aErifer 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 asnrmptions. However, if acural conditions vary significantly from the assumptions, the potential impacts may be more or lsss then identified in the enalysis. In addition, the cumulative impact of groundwater with a nitrate level of 4 mgll diluted in the Roaring Fork valley groundwater rny be significant if the existing nirate concentrations are high. Therefore, we recommend that the applicant develop a baseline and long-teun water quatity monitoring plan prior to final plat. The plan should include a threshold limit or trigger at which mitigation of potential impacts would be rcquircd. If you bave any Erestions or wish to discuss this in detail, please feel free to call. Very tnrly yours, WRIGIIT WATER ENGINEERS, INC. PMB/MIEidIf 92t{47.W Senior Water Resources Engineer Michael -36' -'09' 9,S (THU) l3 : 2l l{R IGHT 1YATER GLN1Y00D TEL:9709459210 P,00t TO: FROM: DATE: RE: MEMORAhIDIJM Mark Bean, Garfield County Planning Office Wright Water Engineers, Inc- Pe9gy M. Bailey and Michael Erion April 9, 1998 l,os Amigos P1s[iminery PIan Review DR4 F7 We are in receipt of additional drainage analysis and ISDS analysis for rhe proposed I-os Amigos project. We reviewed the following documenc. o I-os Amigos Ranch prcliminery Plan, Filings 6 tkough 10, Stormwater Dercnti-o! Analysis, April 1998, prepared by SGM. o Memorandum o W'WE dated April 8, l99E from Dave KoE, P.E. with SGM. r [.os Amigos Ranch P.U.D. Individual Wastewater Treatment Systems Groundwarer Impact dated April 6, 1998, prepared by Resource Engineering. . April 8, 1998 letter to WWE from Rcsourcc Engineering. o April 9, l99t Ietter to WWE from Resource Engineering. The following are our courmcnts. Drainage Andysis Iu general, wc found the updated drainage analysis including detailed calculations for detention pond sizing and operation to be accepable for preliminary plan submittal. The applicanr is proposing the use of four detention ponds locatcd in the upper reaches of thc four suFareas within the site. Volumcs havc bccn calculated fes maintaining historic runoff, under dcveloped conditions, for storms up to and including the lOGyear flood event. Calculadons indicare that all post-development flows will be at or less than existing condirions. The detention ponds tbat were submicted were a gcnedc computer gencratcd pond configrrrarion developed to fit in all four basins. Although thc calculatioru indicate that this pond will work in each basin, the final plans shall include a detailed grading plan with srags-storage volume -3?- *rL l:'L8(THU) l3:21 lIRIGHT IYATER GLNlvooD TEL:9709459210 P.002 MEMO TO: Mark Bean April 9, 1998 Page 2 relationships developed based on the acnral topography. SGM and he is in agreement with our comment- We reviewed this with Dave Korz wirh We believe the data zubmitted fulfills Condition No. Recommendation. the Planning Commission ISDS Impact Andysis The Resource Engineering report concludes that their analysis, together with the commitmenr to construct and maintain qualiry ISDS systems wirh desigu st ndards and management plan, indicates that there will be no adverse impacr to groundwater Eraliry. Based on our review, we generally concur with rhe Resource Engineering conclusioru. The analysis includes a numbcr of engineering assr'-ptions and judgment. We reviewed the analysis making mote conservative assumptions h aII cases and found that the Resource Eugineering analysis would result iu a custulative total nitrate concentration of less than 7 mgll. This is less rhan rhe Sa:e and EPA standard of 1O mg/I. Given the applicabilicy of watcr quality sandards and pollurana rlpicatly associared with sepric tanlc/leachfield effluent, the primary polluant of regulatory concern expecred ro be associated with septic rank/leachfield effluent is nitrate, Niuate is rypically selected as the limiring pollutant from the regulatory perspective for several reasons including: (1) pollutants associated with septic tank/leachfield conamination are cornmonly loown to be niraE and viral/bacterial contaminants; (2) nitrate is hown to be highly mobile in subsurface environments, while viral/bacterial consminants are more easily absorbed onto soils; (3) the regulatory limir for nitate is low relative to typical nitrate loadings in septic sysrem effluent; and (4) niuate concentrations are quite low in rurdeveloped and uncontarninarcd strcam sysems. We believe this recent dctailed analysis fulfills the submittal rcquirements of BOCC Resolution No. 96-34, Paragraph 5. WWE previously rccornmended a monitoring and mitigation plan in the absence of a detailed quantitatiye analysis. With this additional analysis, rhe stringent design standfids, and the maintenance plan, we believlthe applicant has developed an acceptable alrernative approach as outlined in Condition No- A of the Planning Commi.csion Recommendation- WWE will have additional deuiled courments on the design standards and rnainrenance plan. PMBMJETdIf 92L-M7.W g* '38 '