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HomeMy WebLinkAboutHIGHLAND MEADOWS GENERAL AND REPORTS PART 2 LEGAL.pdfDRAINAGE AND SLOPE :STABILITY ANALYSIS ' --HIGHLAND MEADOWS AND. VAIL VILLAGE WEST-SUBDIVISIONS !t :, Developed for the Town of Vail, Colorado Job No. 1845.OO1 August 17,1982 -CL.\\'CO|\I I} ENGINEERI NG ASSOCIATES. INC. SUITE 2O7 VILLAGE PLAZ,A Gr-ENlr'OOD SPR|NCS. CO 8t60t ,-rre{r1s;;4fi...*- I '{ ' o*rl, AND s'opE srasr,,rry o"o?,*HIGHLAND MEADOWS AND VAIL VILLAGE WEST SUBDIVISIONS TABLE OF CONTENTS SUMI'IARY BAcKGRouNo ...:.. " PREvrous soiii 'il; ' ;;;ftidi ' ffioRil : :EXISTING SUBSURFACE DRAINAGE COr,rOitrOr.rS.ExrsTrNG suRFAcE DRATNAGE conoriiows.... LIST OF FIGURES FIGURtr FIGURE FTGURE FIGURE F IGU RE . . . .. POCKET AT BACK . POCKET AT.BACK APPENDIX REPORT oN GEoLOGIC HAZARDS INVESTIGATIoN AND SUBDIV],SION EVALUATTON, HIGHLAI,ID T4EADO}IS SUBDIVISIONS AND VAIL VTLLAGE t{EsT, FTLING L & 2 By LTNCOLN DEVoRE:. PAGES I. II. III.rv. It SLOPE STABILITY 1-4 5-L2 13-rs 16-I7 18 -20 2L-23 24 25 26 >rF- Proj. *O rrnr.oo]. Page I DRAINAGE AI.ID SLOPE STABITITY ANALYSIS HTGHLAND I\IEADOI{S SUBDMSIONS . AND VAIL VILLAGE WEST SUBDIVISIONS SUI4}IARY AND RECOI4MENDATIONS @ This report has been prepur"d u.,d-". contract to the Tovrn of Vail to evaluate the curient subdivisio" iiv""lsi iaentify critical problem.areas, verify construction'of piannea drainage facir-ities, .identify areas of possibre'fiiqn density housing, conduct additionar |eologic i"ireiiig"tion ana provide a cost estimate of recommended improvements ior Highrand Meadows, Highland-_M??d9y:_Filing No. 2, Vail Villige West Fi1ing No. 1 and Vail Village lvest Filing No. 2. Extensive soils and geotechni_ca1 investigations were completed on the Highland Meadows subdivisions as a part of_their pratting during the period extendinj riom rizz through 1978. No soils or geotechnicll investigatiois have been located covering the Vail Village West Subdivisions Lincoln Devore, Soils and Geotechnical Engineers, have prepared the PreLirrinary Report on Geologic Hazards rnvestigations - and subdi-vision Evaluation contiined in the Appendix to this report as a consultant to clayconrb Engineering associates, rnc.The Lincorn DeVore report is i compilition of-previous available studies and independent evaluationl on the pari of Lincoln Devore Recommended surface and subsurface drainage improvements and slope stabilization measures are illustral,ed oi Claycomb Engineering Associates Figure 1, Existing and Recommended Facilities. VaiI Village lrtest Filing No. I The Preliminary Geologic Hazard l4ap by Lincoln DeVore rrrustrates that a substantial nunber of lots in the undeveloped portion of vair Village west Filing No. I are in a metastable area wher€ extreme caution should be taken rirhen units are constructed. very thorougfrly designed mitigation neasures will be necessary for,lhese roli ivrricrr ihould foilorn' detailed s.o---tec;rnical investigations of each building. The nearly.veitical road cuts on Arpine Drive and sierra trail shourd be iut back at shallower slopes and/or retaining walls installed. Due to Ene metastable condition of nuch of this area, the design of _tfe.slopg cut and/or walls should be very thorough, ancl-preceded DY detailed geotechnic studies. I. ,l Proj Page o .N 2 o. 1845.001 The majority of the developed lots in Vail Village West are on stable areas as indicated on the Lincoln Devore maps. Surface drainage improvements should consist of roadside ditches, .curb and gutter, or paved swaLes along the roads. The anticipated repaving of Gore Creek Drive should consist of total pavement section reconstruction,as the current pavement exhibits characteristics of total base failure. Hveem tests are currently being conducted by Lincoln Devore for pavernent design prr.po".r. subsurface drainage improvements are recommended throughout the portions of the Filing that are designated as netastable,vrith an outfall to Gore Creek. These drains vrill not, in themselves, provide stability for the area, but will provide a positive outfaLl for subsequent individual unit drains and retaining wa1l drains, while generally removing excess subsurface f lorv. The landslide on LoE 22, Vail Vi11a9e West Filing No. I (Bitetto Lot) clearly illustrates the hazards associated with construction in the area when proper precaution reLated to slope stability are not observed. Re DeVore Hazard Map illustrates one o ower na zar Vail Village West Filing No. 2 The Prel-j-minary Geologic Hazard Map by Lincoln Devore illustrates that a portion of Lots 4L..43 anc'. 4.,5 through 50 are in a high hazard zone. Virtually all of Lot 44 is in the high hazard zone. The remaining lots are in a low hazard zone. Surface drainage facilities are recommended to properly drain Gore Creek Drive, consisting of roadside ditches,curb and gutter, or paved swales. The anticipated repairing of Gore Creek Drive should consist of total pavement replacement. construction on any lot near lhe lxetastable slope shorr.l-d be precedeci by a detailed geotechnical study and include thorough mitigating measures. Undercutting of the me'.-astable slope could cause slides extending into.the subdivisions above VaiI Village Vlest Filing No. 2. : t. I 3 *l''i, 'F :l' ;l .l I *l nl *l .:{:l proj. No. I845.OOl page 3 Highland l,ieadows several geotechnical studies have been completed on the subdivisions. These studies iecorunenaed caution in deveJ.opment of the area, ia""tiiying stable, metastable,and high hazard zones. suuarainlge systems lrere recommended bv certain of the studies ana'Joniideied-i, i-.i"airion of approval by the Colorado stall Geologist and Eagle County. o1ly a portion of the subsurfaee clrainage system shovrn on the Preliminary plan and tne Construction plans has been installed at tiis time. ?he installed system has removed part of the subsurface flow and reduced the areas of- instability to some extent. rt :_s q"."tion".ii"if-Lhe system instarred is sufficient io aear wiln the area wide problems. Portions of the building areas (that is, areas not identified _as open space) appear to impinge ," iiigi, hazard zones. Reference to the Lincoln Devorl gizara lrap wirr illustrate the areas. rt is recommended that the area wide subdrai.ns be instarled in accordance with the original plans under the direction of a Registered Geotechnicil Engin"er. Consideration should be given to^ expanding the open space designation on those rots where the high hizard zone extends outside the Present open space area . Specific improvements such a.s reopening the inlet to the ctt l vert on vermont Road between Tracts B and c shourd ar so be accomp.li.qhed. Asjhr.rilt rlra.wings should. t,e piepared of the subdrains in Highland pteadornrs ancl easementl" of,tarneC for the subcirains to Frevent Luirciing operations cutting the subdrain lines. General .cut-sl-ope instability characterized by slumps and slides 1n lhe exposed cut slopes is evident tirroughout the second filing of Highrand Meadows. AlL of the shlmp and slide areas are in rocations where sub-surface flow is evident at free flowing water (springs) or saturated soil during the spring of the year. The- soils and geological reports prepared during the preriminary phases of Highr.lnd l.teado;rs Firing *i noted that cut slopes and other construction areas could only be ::l:idereg srable when dry. Caurions about possiLle :_"lly':=.dy9 t9 instabiriiy of cur-a"a-iiii 5r"JJ!'ror. hland Filin indicated if the areas were satu."t.Jl -r;; ;;i;-iiff"r.r,"" Proj . No. 1845.001 Page 4 between the individual reports is in the degree of the verbage indicating the extent of the hazards when soil_s 'are exposed to excess rnoisture. The su:face drainage plan for the seconcl filing has tended to accentuate.the subsurface drainage conditions since the surface drainage pattern criss-crosses the slope as drainage is carried in the roadside ditches. This criss-crossing effect has tended to prolong the exposure of surface runoff to the subsoil, allowing rnere infiltration and thereby increasi.ng the available ground e/ater. In addition, the surface drainage pattern has concentrated flows into specific areas whiLe the natural drainage pattern consisted for the most part of diffuse overland flow directly to Gore Creek. fn particular, at the intersectj-on of Tahoe Drive and Alpine Drive, directly above the Bitetto property, being LoL 22, Vail Village West Filing ril, the drainage area has been increased from a historic basin of less than five acres, to a present drainage basin of approximately 24 acres. Very few subsurface drainage facrlities were installe<i as a part of the subdivision construction. OnIy a very small portion of the subdrainage for Lots 7 c I illustrated on the Prel-iminary Plan was actually installed. The facilities installed were at the location of active springs encounter:ed during construction. It is our. opinion, following review of the available soils and geologj-cal information, reviel.r of the construction drawings for the subdivisions, and site observations, that virtually all areas presently indicating instability can be arrested by proper drainage of both the surface and subsurface areas followed by corrective action such as recompaction of fi11s or construction of retaining wal1s. There is no evidence of extensive very recent landside areas wi-thin the subdivisions. The available evidence indicates that with proper area r'ride drainage of both the surface and subsurface, development of the majcrity of the lots will be possible with a degree of risk which is normally associated with typical mountainside development. Lots 7, 8 & 9 are particulary impacted by subsurface drainage at this time and installation of an area subdrain is imperative, along with very thorough individual lot geotechnical analysis, if these lots are to be developed. Lots 1 through 6 are located partially in a high hazard zone, In several instances, the building envelope F Pro j . tlo. 184 5. 0Ol Page 5 3:."'l:* :l-:l: I:.gTd plat_exrends inro rhe area defined l: ":ign, :: :.'d, :n.li""h" -o.ii;;;;: nii"ir,iilJ;=8":i#l: ll ll'S,,::: ., l:^'::i; :iilJ: " :;;.i";::':T:li:il, o5i'ii = !n.ii i:" ?:" :l^. I ^ uI:_..o.ra 1 ly a;";;J-;i;-.;;;:' if;l."i.il ]::i::i: ::1, ":^!_,: I ni,iia- I.i.I-"i' ir,:' ;;inr"H i 38ii" ""u ::::::I::?t-::F":ls for tn"-J","i"p,""I.I'tii"ij recommended,that these lots be-.;;i;ewed by the Town ro l;j:::*1,' j^ ll:^:":::"!ir, u. i r i.i'[Iiiuiiln "!i":ig. :adesuatell, reflecr trre gehoer;";;";;;;*iiir.f;l"Iilli Iefg1: ro rhe previous nulJ-o1ng areas are Thi s replat vras processed Comparison of the Highland park building layout on :l:.:i:tlTl:::y^:l:" to the Lincorn Devore iazard Map '-rq y clearly illustrates those units th.t -.. planned, or in Highland park Highland park is a resubdivision of Lots 26 throueh 42 of Hishland rrreadows. rt is in ""-"r"i a;i il."JiiJi"",Geotech:ricar Enqineer ror tne -l:ighi.rJ-ri""iJrl'iliu, Robert Thompsonl recommendea against developing. subsequent soils a1d- geologic reports wer6 more favorable to the area, with the result th"t pluiting ot tfrai-porilon ot Highland l.leadows rvas; approvla Uy Eagle County. The replat submittal of the area Geologic Reports and states that outside the high hazard zones.through the Torsn of Vail. some cases under constructi.on, in high tr"i"ra zone=.The Town should consider submitting ih" Highr.rra--p"rL layout to the original soils and Geotecfrnicii errgirr."."for review and comment. Based on the avair-able information, the basis for approval by the Town of the proposea project rnay have been somewhat faurty' rt certainry appear! tiat re-siting of certain units is.appropriate and possiL:-y erimination of some units if suitable Lower hazaid localions are not avai-lable. A suitable surface drainage outfalt from the west end of Vermont Road must also be developed. Area tiide Considerations The landslide on the.Bitetto property, Lot 22. vaiL.virlage west lil1"n l, clearly irlustrares'thL polential for siope fairures rn even moderate hazard zones if construction does not foll0w the recommendations of qualified Ceotechnicai rrrgirr."r". Proj. No. The provisions continue to be addition, a r ulrement ehould be evelopment t repar sed on analysis rts be ear e conati.tions o I should b6 n9 at the appropriate -E6 for designs a8 those that ::":::.r?:i :::::::_:?.consider densiry uansfers fron the Erom tne :';:;':""t";" ";:j.'?:::^":.1. :: ?. g'o:p "? ;;i;i:;iii:.v s i tes,3"T::"":? *":::.::p:i^"li:! iriustrates the n,orjI"i'Jj degree of hazard on the site.B:sed on this lnaiysis map, i il :. i J: : *' u " * - lI " : : I : :'. J J - ;; ", -;;; *r, iln i 1.. = i, I 1." i J " I i " I " f ;the lowest hazard areas. Another suggestion that a page 6 of ordinance 15, Series applied to all lots in of the sed r845.001 1982 should study area .on all future In H. I :| t tI t il iol be .?nacted that lhat ttrey have hazard are av,rare o .rnd subdi.vision. i all be ideE s and ma rlor convenance it_em or ordinance PYlghases of lots to indicate The following recommendations are macie to recluce the p'obabiritv of future siruarions devetopi"g-"iiirJ, .o those addressed by this ."oo.i. - ' A statement should be added verbage to be signed by the Engrneer for the subdivision has reviewed the final p:ai an<1 finds thern in aceordance recommenda tions . ' Similar analysis to this reporr may be appropriate for other portions of the T;;;-";'vair. -i".;l;;iiy a comprehensive hazard map could be develoil;-;;;-.the entire Town. ttre provi.i;;; of ordinance 16,Series of 1982 should if,en uu-"ppii"a ro alJ- unj.ts rocated in moderate to hi;h ;";;;; zonos. t. 2. r Par to t-he Final plat- soils and ceotechnical to the effect that- he and construction plans wi+-h his e 1l! .J :} '.|,: .'. $ <.) proj. No. 1845.001 An ordinan.u m.y_li t".::3:rtrequiring purchases of property to indicat" h;i'-;;"i=ntl,r. reviewed the hazard reports uld.-T?ppi.,g-.piril"ble ro a piece of property, lot, or un.it. H.riiJ-i.ports such as avaranche and flood pli:r--;;;;I "ir,ooro be incLuded as werr as geotogic. . These ;;;";r= might be made avail.abte to ootenti.r prr"n.!;;'i" a central loeation Uy tire Town of Vail. The requirenent tht soils and geological reports be Dases on the results or tesfs- lJii,r"..a in the :f.t.l:?-o{ thg year-, or project"o lo conditions of sarurated soirs, should b"-;;;i;"; to arr areas v,rhere appropriate, A combination of factors have influenced the above recommendarions. ^_Il: u*.r"..ri";j:;; -;;;p.ri"-Jlii", o,both Iand and imorovements :.r, i-t," Town of VaiI means lli:..:"'".1"_'s" borrar i;;";; *.i u. associated with rarrures in hazard zones. iin"Jrpurchasers_of pr:operty are commonly froln_outside tf,"--v.ii area, and often from outside the unj.red*1.!:.:.., -;;";";;"not be expccted ro be knowleclgeable about tfre clifraie, geology, etc. of the area. FuIl ais"rosure ;;1;;'st-udies by qualified people should be made ""uifuifJ"io ttrcrn prior to the purchase of property. The Town of Vail should make it clear to all parties utilizing this report that it is not an in-dep+-h anatysis of lots on an 'naiviouJr- ;;"i;.^..tr=IJ,,uu".c,to a large extent, on pr",riou"-r"rX by other soils and Geological Enqineers. Neither t.ie Town or the consuttant tein i1 p1"1""r;";;ni;".rins Associates and ::ffiil":::"i;"":" be responsible, _for i"Ji"ij,"i=i"t consrructed by "i;::"t:"::t:;"o5:;:i$*L:.:i;l;:":".properti.es. AII of the ,""o.*..,aitions contained herei.n shoutd be viewed ;;-i;;";;at _ reconmendarions and not consh-rued as a requirement-. that the Town, or any other party, construct the facilities or forlow the recommendati.ons . 3. 't il I ;ict_, 1j ii id ,i ,-tD ,+ ':, 1 rl ::' I ttl -.i: I :s. I I ! {l Proj. No. tB45.OOl Page 8 Lincoln DeVore, Soils and Geotechnical Engineers, have worked as a Consul:"!: to CfaYcoiU EngineerLng Associates in preparation of this report. The following material Engineering for review pri-,to Claycomb 1982 : Plans, roads, v/ater and sheets. As-builts was provided ro July B, Highland Meadotr/s Construction sewer, noted as as_builts, 2L dated l-5-gO. tlighland Meadows, construction plans, ro.tds, v/c.tter and sewer, Filing 2, as-Uuiiis,-lO sheets, date of as-builts, I-5_Bo, l-lo_go, ti_to_lg, prints. Mylar sepj_a, EIIiott Ranch Subdivision plat, sheet 1.. Itylar sepia, Highland Meadows Fiting #2. plat, 2 sheets ntylar sepia, Resubdivision, Lots 2g_4O, Vail Village west #2, plat, I sheet. MyJ-ar sepi.r , tlighland Me.1dows, plat, 2 sheets . Mylar sepia, Vail ViIIage i{est, Filing *2, plat 2 sheets. Mylar sep:'.a, Vail Viltage West, Filing #1, p1at, ]sheet. l*lylar sepia, Matterhorn Village, Fiting *1, plat_,1 Sheet. Sketch plan submittal, Highland Me.rdows *2. Letter rePorL by Terra Task to Doug Bitetto, 3_5_82. !:.:jf. report by Vloodward-Clyde, Consultants to Town of vai t, rega rrling Bitet-to pioperrty dated 3_lg-82. Preliminary Engineering Geology .rnd Subsoil rnvestigation, Highlani Meadoii sunairri."iorr, Filing #2 by Chen and Associates, ,June 30, l97g. The following items vrere received by Claycomb Engineering Associates, 7-A-BZ. a. : 1 k l. ProJ. No. IB45.0OI Page 9 HighJ.and lteadows Filing *2 topo showing Vait Village lt::! Filing 3 roads i"-piu".,'1,,-= 1ss., 2,rntervals. No date or i..orit of who ,upp-a. Yiil T"=: R,rdge::l?, 1,,= 50,, lro dare of ftiehr or record of who rnapped Sheets, L,2, &7 of ?, -Highlands Meadows Filing *2 Pretiminary ptan submirtii-uy-rx'dua. #l Preliminary plan #2 Utility ptan #7 Typicat cross Sections sheets.2,3,4,5,6 & Il, of lt, Highrand Meadovrs Preliminary ptan submit_tal-;; ;A;;A #2 Preliminary plan *3 Grading and Drainage plan #4 Utility Layour #5 Landscape ptAn *6 Typical Cross Sections flI Preliminary ArchlCeeture by llarold Engstrom, AIA Specifications for. Construcr_ion (not titled as such)Highland Meadows fit ing . #2 . M;t, 'fgZS, -"i.""rra-iy' schmidt-Tiago Constr,rciior,' c;;;n;. Preliminary Subsoil and Vail l{est Filing }Io. g,IO, L9?2. Geological Investigation,Chen and Associates, October Engineering Geologyr Highland l,lendowsr Novembpr llf r I?,l, by Charlus.ti. noUinson anJ assoctates, Inc.v./ithout figures (rig,lre" s"il""qJ""ary received). ceotechnical site evaluation, Lot 22, Vail Villaoe I,Iest piling I, Chcn ancl. a""".i.uio", -jrriy-t-,'i;;;:. ?:ttt rcports by l,Joodwar<l_Clycle Coneultants of compacLion tests and observ.iion of base course placement and utility trench -"o*pu"tion in Highland Meadows Firinq 2 and Hignr,ina-r.t;iaor" fr". s-"ifJiil.,16, I9B0 to N5vember fgl fggO. Vail Village West, Filing #3, plat Speci. fications for Construction ( not titled as such)Hiqhland I'teadows, May, igig) executed by schmidr-Tiago Constructioi' c".piny. Numerous items of correspondence relative subdivisions. .T 3 .f I 1i ls * . t:i '.1 *:;l '+l il proj . lro. 1845 . 0Ol page l0 Material received from Leroy Tobler g_3_g2. aa ' Letter frorn Tobler commenti.ng on draft report letter included *:p__?f t".;ii;;";i subarains in hiJrrrana Meadows and.Highla"a f.f."aJrs.Filing 2. A copy of ierrer to Tim 6"ra;; ""-i6_sr_29 was also incruded.ab' pages 2 and -3 0f retter irom charles Robinson to Dave Ermore ("" -g?i: "" p.g. i-ii"sing), retative Matterhorn Village buiJiJirlon Frling No.2. ac. Xerox copies of large Robinson Maps, Figures 2 & 3. ad . Surnmerl ee l virrage "riiilt;; .3-24-7s' resarding Matterhorn ac. Chen and O.:::i_.a."s^daily reports, Lglg. Reports numbered I through gr, uut with numerou" ,u.tor"missins, sucrr-asi#3 .-rrrouji,-zr. o;i;-;#ii|, rz_rz,30,34-36, 39 & 4l "r" -f"i,road compaction. AII other reporrs are forutirii any rereience to site "o,,ai;I"::"?:l:i.u litl"jil.n"" af' sutnmerree t:l:t:: 3-lB-75, regarding Matterhorn Village Filing No. 2. ag' summerree t:!!ti: 3-72-75, regarding Ftar-terhorn VilJ.age Filing #2. ah. Robinson letter, 3_Lg_75, regarding Mat_terhorh Vi.IJage Filing #2. --: ai. Richards Eng.ineers Iettar, 4_4_75, regarding t!at:rerhorn Village nif int' *i. aj. Chen and Associatns prelirninaly EnSinegfinS cc.ology if i;i;:i1 rnvestisati;;; ;ltt"rho'n virrige, .rury ak Water and Mineral. ConsuLtants, Inc., Environmental S3ltll", ijr r.li, T". t.'noin-vi; i";;' suba iv i sio", "rj i i"g :::: i::::I;l;1t;r.t, resardins vermonr Road rocation ff;;,.1;:';:;u:;::tt' resardins waterline compaction, r-i ak. a1.Chen letter, 6-5-79,across Vermont Creek legarding Vermont Road fill j-n Highland Meadows. i .: I a il '{l am. an. KKBNA letter, lO_31_79 to Tirn springs near Lot Za, HigfrfaiJ proj. No. t845.OOI Page ll Garton regardino Meadows r,ifing *2. sumrnerLee report,. preLirninary SoiI and Foundation i l: ";:;ffi l?" i rT"l3.,r,o," vi i r lii' suua i.'., i " io,,, -ii:. ine ao' summerree, supplenentar subsurface rnvestigation and SLope Stability- enafysis, -lf.it"rr,orn Village Subdivision, Filing l,ro. -i, -'ieptemU"r 24, 1g74. ap. Part 2, physical and Vegetation.being ,,Thompson, s preliminary plat Site Characteristics, Soils, Geology lloted in Tobler letrer of Z_3-g2 -is report included in Vail Ridge submittal... handwritten memo to Tom Everett,to utility trench comp.rction. aq. ar. as. Thompson letter, LZ_L6_73 to peak One Company regarding Vail West Ridge Wright Mcl,auqhlih 1O-2-80, relJted Photographs supplied by Leroy Tobler. Alpine Drive Sq/itchbaek :-i?-9o - Lookins downhilt a+_ Lor ?-.1^u, - Looking ar- sl.ope failure ]-n cut slope.rrith rock toe t rr .t\rv-ou . - LooKtng at repaired slope protection. 11-80 - Closeup looking at repaired slone. Circle an<l Tahoe Drive int_eyssslie.- Looking at slope failure Road from Vermont Road - Looking southwesterly ;rlong Alpine. ::}";_Tl;cellaneous information received betwee n 7_L4_82 at. Individual soils reports on Lots 26_42, Highland !:.i3;;, by ilerry Klus and Associate" a"i.d"r.rovember au. Letter from L.R. Ladwigr Colorado regarding Highland Meadows, dated 25. Sequoia 5- 19-80 AJ.pine 9-10-B 1 Geological Survey,l-13-78 Proj. No. t845.OOl page 12 av. |;:i5t: letrer resardins Highrand Meadows dated alr. Chen letter regarding cut slope failure, Hiqhland Meadows Filins #2, g:ts_tg,-ifupi;;-;;ii"-.-,..,Switchback). _Clren letter regarding .ui slope failure Hishrand Meadois r,iiinJ-Iz]-Eli_eo' t"".ViJIage trest FilinS *1i. ordinance #16, series Lggz, Tovrn of Vail . Denton Associates, fnc. ]etter regarding Highland Park, dated 4-24-AI. -- --: Memorandum to pranning and Environmentar commission from Department of coilmunity--o""Iiopment,/peter patten regarding Highland park ctat_id-S_i+_er KI(BNA dat-ed L2-2-77 adjacent 22, vaj-r L-24 by Subdivision (west ), Lot Highland Meadovls to ay. az ba. bb. h€ b9. Prints of Highland park drawings, sheets Denton Associates,. dated 4_27_g;'. Linco.l-n Devore letter report, regarding rnvestigation at Landslide, v.ii'virfu9.22, Fillng l, 7-30-82 CTl/Thompson, Inc. letter to regarding Highland Meadows. ::::;"i;1;:_;H'""ement Asreement, rrishrand Meadow.s, Subdivision fmprovements Agreement,Filin9 No. 2, 3ot"d LI-22_it) Protective Covenants, Highlanrl Mcadows, with Supplernental planned_Dev6lop.".,l-n"gufations. The Robert.w. Thompson, fnc. prlriminary ceotechnical Investigation, Vail_tlest_Ridg- er"p"rty Ctated .ruty lf, 1973, reviewed JuIy 2a.-igZ!,-"r"" received from Leroy Tobler at the Aufust 13, i6eZ r".ri"r-r""ti"f. J j f iI!:'t|"' 1a4s'oor B.BACKGROUND OF STUDY AREA The prelimin prepared ir, .vo""ill.oii"r5?; :* l:.qll:lu.Meadows subdivision v,as ;iifii i:', 1"".'| ;^ u:sr " -cJu,,ivt;Ji::;:i" i:.:.ff:'Ir:j;i;l:J;:. " ::: _ :l: -"iii i ili'i" i;"i:I".':.i "ff i5, i t;;_ ft; . :1iF*d;n"'nfii= iiiii:::;i:r ll'::.::!:.;;-;Iv^iru.n",^r_r:r is Ju,ie so, ,e7s. A :::::::-.i;i'"ii, iii";:;:,:",1l -I;*;_T!?To"e" and Jsso"iat e s . rhe /tssoclates. oric Rrdge. consrru"ili:l itp"tiJ"t5i. unarl'es s' Robinson and by chen and Assoc.,t:: "f.in"-i".i=tr to the development as Va'l ;;qi":s ti r;:3i::i : :' ;i. ;s ;; ;ryt i+. ;!:t'i.'T'u:. ff"*::' ::.. :l_" pr"'..i"g i:'i";f"u"':1,:J:"..11 Fg' ;;;;-;";:*ed subsequint rtovember 19, fgAf f"fiorf"-i'.'i""qfne actual acceoEance is a..t.j" 11-tion by the coirractor, schmiatllly_checklist .ta "orr""ti.rJ--;:?i:0""'rv br:en repratieJ ;iil;;i::;' ""*';rij,jl':i:irj3";:;" "' ' 'Tho Highrand-. I\te'ldov's 5rling #2.-subdivision is .a reprat of Vair iiii":;"y;"irirt"t.'nn-f i, t"g"t;;!' with " p;;l;;n'it .n. proposed i F i* :i i ; r iii :; :i" ii 1 6j* l, " $il,;,ii5li;:: r: {:irii" ., i: I i]: i: :i i ii: i ltiiry ; l.ij "€j+Tiiiry; : ", il:" fu ,iti:,lrt i,, ";;.'i:,,1::"t;iii#':pg:i" i"'-inf'porrion or tne froposea ; : " : :: ; - ; i ;: ; : " ;;" ;: i :i'1,1' o:l : :l:ij lxii " : "d ji. i:, iiii i: "$" ", " ";;":;H:l:i:..:: .:nr:'..i ;: ;;;i;" iit ::rri;. ;; ;; h jt"iili;{;l'i:i ;l::'!i,ii:*'i::;Ls'll, *j-9. ji:. i:;i:r i"?ll'.,-'"r the'lp r u tl"'r" "ii".i5""ll5 i3;": ?l:":i -ilru; : r '.q e c-:^...: r r - - o.- ou r rt arau,ilsi:li':r:'"l5i:,:.;;i" tUirj"i.::"i;!: =l gr, I:# .;;:"1:I-l?"9. ure ioaJ-;";;;,;:;i:" :og utirify iie,,cn backrirr ptr,.Jri-..*"_oy. chen and Associates-in tglg. __ii"ru.l" course l;1.;*:;^F::lr, l::.;;:,":;.il;8. *,:;;::j.:f x:r"=u.r_c: yao in ll:.i;li ?{ i:ii; havins u"". .iiJ*:d :o. i;;';;;,";i""":";f"'":rH-", ;rl; jllj: ior-r-Jiincountv' tnt uenfi".r reti"i-i" iu..o November "": contrac.;;;";:iri.i:l?:H.checklist a',a .orru"frve action by t" r xi] lI v.i-rragc r'resr, Filing No. l, -yu" recorded in Eagre countv iorr.,^-' very few. records "ii"i'oi an. subdivision "rui.l.!1.:ni"o;:;i:.":::;g:;;; ;;y extensive J#r:i:$i"e .,,J' ;il:'tX"' rB4s'ool VaiI Villaqe west, Filing No. 2, rras recorded in.Eagle County in 1965 and alJo predated .*i".rJir. subdivision requrrements bv Ea-ole countv' Lot; 29 tiri"rgi-i6'*"t" reprarted in 1968. i?::1":::"1':?':::""1-:l?::-:.'ult:te and sridins, tosether :iiii;":: ;i;ii":"' ;:::^::;iil::ii igi:'":::.;liullnhj"::::::with sinee ::l:r?"::,:inlj:":.::*:ii'ili_;q. d:":"::;:;::i";"n:l:J"ff:construction was "o*pr"iet.--ii.': L"s (-:ensEructron period and surfaced on ttre gitetto 1..,r_ r.,*i^*,.I9.,":,problem in the region ;:lfil'i, :",;::. ".":i:j" i::; "::i.:-i!";i."1?":;*uil,'li, ijil"fi"..niJ.ing #1, where a slide .*1";;;-i r's .Lot 22 of Vail.Village wes of ttighlana u"oJor= Fi.lin.-. *, --r tI:: M:-' Bitetto's lot ""[" i"I ::,?: ::. :?u^l;? ::";. ijil "; ^ E"Iiu'fil" "i; " u;l;;I; ;_*:; :lu."n:;:u' u Little evidence of crrt .tr ri r r ^r __ _tand Meador" suta,f.,i-":^:..I:ll."r"pe sturnping is evident in fli;liils il::sfl: :::lj:i:;:l"l;::i:,. !!r"::l3i?s"iij't::ff;t :::Highrand Meado!,rs :-"oic:*iJ-;;.;':;"''r'ne construction drawings toi system was to uo .o.rr.ructed .i..r,'iflitsiv-e sub5urface at"i""6i --' I !1olli.'"::;i l::'?:. ":;:;:,-:iiT "i;"3' i"ll,ii"i:*:":::"%: : j"::: i ; = ";i$" i; :; ::: *^ :li: : :ii: i:'.: "ii':::"Ili, ""lii'.f l='j system was to be constr""t.J* i-:;,, s'rLerr.'rve subsurface drainage and the instal rati:;t':i""",:;j'.-rl:-tri:ns. both ;;;;;;;" trench drains :;_H:l: sffir:ff=:"t.:,:-"li!iF.:: :it- i;:::.::"til":;.,3 ex,en, ?t -!h" road right-or-r.y. --i;i;;;'-r'qe or sanr'tarY--sevrer easements inoicates lt,"i'"!""rar or ."- -^^-'l::i ::petied by Mr. r,"r"v-r"Ei"i indicates trrat"sev.r"i-:; .;:':::::i:: :"pqri9d uy Mr. Leroy ro sewer line) shor+n r::.1*:r^:*-:.:t:l"t* sulirair"_i'o. part of a subdrains when they are locat"d or"t*tt to be eassments for these or the r""J"rioit-or-r"",- r-r^---.til3"^:f l?"lt,."y sevrer easements sewer line ) shor+n on the cJ;;.;;:.-i;;-ni:;:';..ll,lll.rf$".ri:": '}i.tt:;:';l".] tFlir,f,"ii:" *l- :n:., i.'luv-:..r occurrerl on Lot 22,::i:.";l li':"x:::"ii*;i,,i i, ""ti': 3:iii":ilii .;::fiff:"t",l"i,,'l j :; :i1i:'L":il:':i:s"il::::'l:;l_i:i_ :;ilu"l.i;" ]"fu " *l;;l:li",:..outr.ine of the sriae'"rJJ i:"i;;:.;l,l"ll.i?l;,"t1: 19t:9 with devastating =,.,iit""ir-o I'r'roe' llrst documented in partiarry ";;;r;;;d housp rrnrn i.^".I.:::l^ 9, re82, knockins a \r^ Construction cut -v. - _r nave been Ieft small slumps in these slopes al.ong ro.rcl s J_n a near vertical slopes is visible. in Vail Vitlaqe configurationl West FiIino Evidence oi The nreas slope a'.able iay be T::::l.I^"I_ylil vi.i.1ase rlest Filing #2 is ?:li:::: i?..-o:::,^i:::I'lF il;;"";:#'i'xi,l""i;"':; ::::t:il:::= arrhoush :;;; ;;;";;r;1";'j":'::i of recent cons idered l1:::::_ pe_conaitio"-;;-;;;';;"il:i; ;;as a total failure of a road surface. into narginally Gore Creek Drivl .:il \r * prr o"Jl ' t l" ' l 84 s ' oo l PREVIOUS SOILS AND GEOLOGICAL REPORTS .,.j5:i":;ff ';i::::: ir:i,!H':;:'I"?i:,:,ff:""red,real ins v,irh the Prcl iminary Subsurface and Geolog: iXirt]"n') i"est Firins #3, ..."I'iii"i:";:l:::ll'El?l;"I"ii, IIJ SuppI enen ta 1 inalysis, 11a:--()ct . 2.1 , ]-9? 1 .ore1 irninary Geotecirnica I Property, R.l{. Thompson, :-:Ii::1":ntal Geolosy or >_ur:o1v.ts j.on, FiI ing No.lnc. , ll'cvernber l-g, 1g73. Prelirnin.try Soil and Found.at:.on I:vi l- 1 a ge sus.i i "i. io"- "l iiII':,:t"^ r nvest i ga" ion,,r1;1 11 *'rlrnrn ),'ov. is, i;;i;'-rcn F:-linc ^\Io' 2, ':-hcma! ;:-;;r;";;:::"t" Subsr.rrja.ce fnvestiqatj-on ani :erhorn \rillage suioivi=i;;; i:::"i;?3:ion vair lvesr Ridse , tn:,_,^t:*, a" rhorn Vi,,. lage z, ,.r3 r- !: .rnd l.iineral 6onsultants, 5lo_ce Si.rbilitrz l-iiing )lc. Z, iJ;rg r n,:,:r ing .jcclogy, i.1-t:l .1.ssr)c;.a-_,,s, i nc. Ilt gh l anC l.lercorvs, Chi.lrIes -'i ovenle:- 2U, ,.9 j7.S. Rcbi nson :,'-s l i -r :_ _-,..,ri:1_ ! :.:,5i n.r::1nE csology anci Sub_sorL .;; ; ";;i',1.;l;; r ;i th i a ;J :: "' c ";-"i iu'cd j. v i s i o;r,ES, June 30, |-gj,a. rcports have al-so- b:::. preparec re I,rt-ive .-,5e lancisicle !'ait Village t.:est tiling *I as follows: C--.,tc:h;tical Si te Evalua--ion, Lot Firin3 *r, che_-i -anci a""""i.-i.I":";,i;, r]"rtjrJ]rlase rresr LeLter ;eport, gitetto prcperr.y Tcrra Task, March 5, lgAZ.Letter report, Dc consuIran'.", -,i.rlltrSiiltlSallopo"v, Lioodward-cryde ;::=!; :';i, il;";i:oi:::1,:."3;::: :.;:,;ti; . vi lrase wesr, ..t i{. t ..''. !i I YI : -: ,;::::-of sone of the daily re: '.,... -fi:r'ct i'n r est i ns,iurins i oi60ilJ"t;:H :I"ffilnl"nnl,l:;:::..=.''"il:'^'"Dorts o::_i:'=:nnl -i"oi:" os irrri-';I#..-rorrns and the - 'r r rr - '.'- ''o;rn;1't i on tesrs pr'rrfoiiea >y :.ro,ra,.1,.arirEr.yn" consr.l tants o"' ;'D':r'or"?;il';:::":.::.::o;il:jf ;;oi'J,"l;:l"J!..ooo, and .l I ;il:'.X"' r84s ' o01 Although the i :::yj:iIi:iit ": i!.::!::i: " ;i: iirg_=iln,tnjn:":::ii,",;b<, ivis ion reas make s im i.L ar na suusui r"""''ii. i,i.';:;::"i:.jji:iI:: :i:. fi"i:::i:: :;":i;l:::the follorving excerpes:hen , I972, aqe I age 5 -':ti'-: 5 I O'7? ?rin r.u .-ar. !1 ].!,'1978 ir:.lts_r. F I . rtc .. "Soils have saturated. subsurface ll:^.""oency ro stump -:'l]. necessirares good orarnage throughout the rvh en surface and property. wash, vrhen these ;-; :::J:lnt.jo*t^t:.: unconsor idared slope I:;:- il:l.a ted . tenir ;;-;;;;;.;io'T".lJ 3::::l:::. _ rhis -.i"*ir"g';il":l; T:::saturated areas are ciai.iea. i .);)tIt5()n i.-: - l "f t. is reconmcnded mrnrmum depth, on no steeper than I snould be nacle fo;ernbanlirilents.,, "Cut siopes heigh+- over cond i t ions . tha|_ aLI cuts be j<epC to a l?: ?.0": -of to to 1B feet and _r ..l. Aoegua +-e provision.surfaee drainagc through road shou Lcl be sr-.rbi e most of the ..1:- ea are ininirnaL . ,, at I: i at 2O feet ',;hs:'e grounCwa+*er and. subsurface rjr6 j;.16gs sta'oi.!.iry of much of ilie " f m-o:-ovement of surlaee r.ri 1l inprove the slope P rci)os e(i devqlOprnent-. " lihenever ground rrai.er cul verts or perv j.ous control in fi I tra tion sluffing of the cut.eonsidered be ca us_o of L Ls encountered in a CU.-,Dlanj<ets should be used to r-nto fil, I and t_o prevent Buttressing shouJ.d be sJ.ope stability problems.,, "Previous blankets may_ be ncjedcd beneath other fills on the DroDerty it aa.rers" groundvrater conrjitions ora on"orncered <luring construction. ,, "ff seepage is en sron.. in",+rr-.i r. ---"?Ytt'tred in cuts, the risk :*:i:, ll,.l"p_i t: ty i s i""i""""a I"..;: ;:"":.1 'I"Xi.i3l'u hctwov.'- i+ .iE :- drain.rge shouid be provicied for .i.-.",]illi l;:," I^",;.^ t l^-rj . l:, -I t i n i i i i; il":::?;::::;:, ;?ii':.::.::?1"::::^F:g: ;:;-i;;=i;':;:'3::0.n. xj_r I ".1::.:::,1 I. .:1""t - t19 i'i'.'.*o jlo ":;,. ;::: ,'I::-:lPa. lining of drainage ditches rrir-h tmpervious membrances such as asphalt or concrct() to prevent ar(las urhor" -i "eumu Li.l ted surf(-rce rrater can. percolat-e ctown inco tne subsurface soil st_rata. lr," "irl,i I i t_y of I'1J ::]l"yi:t rype stopes can ::Iec:ed by induction of gl9:"d water into areas ;il: 'rNo' r84s ' ool be drasticallv subsurface vratir or _of. potentiaf siope ?:,1i:y"A ilrat subsurface probably be required rocated in colfuvial soil faiLure planes. ft is oralnage sys terns r.ri 11 around. alL structures areas . ,, Thr' various reDo:-f c F^r -!.:--.ncjicare an"_",.f iipoi.rs relative the Bitetto rea. Ttris serv"==ullt of a spring- surfacing ta r ernent s - """" =," r iij"!i::?i :"': ::::iljT ne various subdivrston reports. Lot aLso cle.:rlv r^'i t_hin the sI ide of the accuiacy of the seepage inctuOed in i..ltliI""3"Iilt"ff ::;i--':u..*::1..:l ehe repcrts ror t-he i!d:"l:l"l soils ";;;;;;"""""in5"tt or the repcrts ror t-he l:,i:il of ttre year. Thereforc - *I^"tI.1|.1-iewec r,rere ccnducted l.n :h". iuil of t5e yr -"- :s\Jr'\'J:y Enat,were. revieweC \,rere ccnducie ::::.ai-,io:rJ^*;;; Jilj;".I155"or3:i;_"lt^,',-,:il;:i"",joll,,race i,ater :j:di^.io:rs *".a lar,--- - r,rer erore, tlle miniinu;r s,:bsrrrface cs.ervarion. Mosr ;::::::":-f^u.11v_5i," J;iiil";,,JiJ, rr.ro cs.ervation. tqost -*"ssr q;(r qui-Lncl the.drilling and fiel<l :cbebre ccnaiticn:.i:T: I.?*^::""p.ecific_p;;1";;;""s or the :cbebte ccnditicn--'-*+s€ r.cine "" "f.:::fic_projectj.ons of the i::,::=T::;tl-",ill".i: ::';:":::=:,9!::l'.:i: _:;;i;; and earry :,:.^:"=-:nonths v,rren trJ ""ii""Ili=3,.1:Ji:t the sprins and eariy ::;:::.:"." $/ater. The rgz+-sr*i":i::"::_:c-c-ttensive surrace and :ibsu:fece vrater. -- *. iii+'="r"ii.iYlJ"!! ." e:rtinsive =urr""l ::l lcl','ing caut j.on, tee report does inclu.je the I t , t il il , I9'l I "Nore of the ro.io t i""," ";, :;;:nf ' ;:_:";::: ter ed - r-i rn bedrock wit-hin ._n. ""ii^";:;rr-Y:'- t|I?: boulders lrere presen-...3nccunr_c:-.o oi, prof ii.e . alic,. none "i ii"'eist pirs ii: i, if i : : I T: " i: iT !:', : : #:ii f . iiliii*;'*:i. ; =i;:i:;;t r:::i l^d-'1" t". . ". Jpu g J- :t:lln:. ccu rci crev e r op run-off lo.ioatll= during the spring thaw .na-},..r,y ::..11.:tl<lit:on to cau t_ ions abour_;.;ti:',:'.: in L,1err cr.tions .=bo"a.9="tttd rtaterr aL1 the reports are ' ;,. j l j :.' ;;ii :.' ?3"*:ij:::":::i" :i:t i:iii. i: ='n: : . *l:jt?'i" i" ."., :rie. rh;rt , -, -ir",""iji"ir_"jn.;::::, but _the basic ihome remains l;ii:".:i:"i":;.'io""'llo"::t;:H.l?:g?:'i= ."g iiigfi."a r,readows *2 ';:;:;t;:;] r ocar srua1r ." rlig."o'i""o'"-"ort"i,.,t="Lti,r""*"rt""i"ul.'- 'i-*-ta:- I '.*trtotu.i i:",.::i:. Hazards rnvestigat:.on ancl ;;.;-ii." ;I^"'"::1?_DeVore as a pirt of rhis ]-.nil'",iol::?::. 1r,.!nis -reFort incrudes the ":t ln-r".r inc. [,:-nco]y_ ogvore r"p"ii'i"Ii=.liin "ir :,s ij3;3t::l:_!fi"jls o" oii-ine previous 3; ;;"i::::, :"i:r::-;;;;.i;;;;i;; :ffi ;:ffii;::,::"i:Ti:::r t! l'..,ii'-" l>y LincoJ.n D,--Vore o= ; -;;--4r'r' 6r'rcr uuldrvision anarysii : : i ;. I ;r ;:;, :A:;iL*#:" ;:irfi" i"ii:lii ;. "x;: ":;":i' -;;;';Ji" . reports avaifable as oy Lrncoln De\rorc. ,'it .,^'",_ scorogy. drawing o" oii-ine previou -. rr elcl invest j.satiJ""-'"Ii*e.=t uorinol Proj. tro. LrJ45.00t Page lB IV. EXISTIT;G SUBST,RFACE Dfu\T}iAG: CONDTTTOIIS Considerable evid v .rrea in thc r"j":; 3:.;:::"i:::^rlow e'xisrs throushour the st udy .rrea in thc -' va -up.'ur'.ace f row L'xists throughout t 1'.',.1,""9 "..io..""'n"':I":j":5'::::, ^ :o^uf:, ".'"i !i sround areas . prev iou s repo !' r s 1.3". "Ji$i' "':';:' "i'i,?i; " "r,,ff"t ] r, eround areas .by rhe fact rhat trre stuiil; ;#: (icrno rr,r-; __ -, ?r._ vrere hamf,erect by the fact that - '"'t-t'su "t*" ::_these. spots, lul_ ur..u-i,lii.,ve.ir. Lincorn ;.;::"::"9;:irHr"Ii.ll"l.l*g.1!1;5";il g." tine or ihe ir idil,io' ":":i. ": l.:*il; *ii3ti":: ":HiEi *;' :::;;o:s,i:ii ;:::ir:i"g: ana seeps--- ts4cv't-tJusrf ma1l1d springs "na =iEp"';5 ;;;i"clher_i"ai""IJiy: cuFFeDrly visibr" or inaiJ;;";..;y veserarion or ye.i:.. Lincotn DeVore;" _pr"iiiii.i, oo.. during rhe ciry tin" oi i-fre,. l.-l?l-pir.ation or ar.r pr"i.i".ii;";::.::o!lIf::: Dr.rrnase Map present other indicatori An ext ens j. ve :::':::t:ti;";i;; il3":;5"::":i:i:i?:- =y:,er. r,as inciicareci on +_he rl:e sir516- con"i,sf.J;;-r;;:.";:::..1".t plans for Highlara-lr"..ra""I.s..ve:-at cross i;;.:o of undertJrainl _uene"f; ;ii s,".nitary ser.rcrs anrr : i:a;' "" ;x" j:j;;';; j ;i::if; :"il::: :r :j. :::g.:;;:.*Fi.-: "' "" -hc s.r.rita.y "",,,..",";;"'in-;il'r."i"j" that arr the subdr;i;"-;";;;;il' --il.'t.:-:o "rL cr.i.rug. systern ho= i--:^:tt:^ll:t! o1t1 .= sn:ar.r amounr o4 "::"r'. T<>bIcr has su:pl ieci infc::nat .--,iry installec. ge inforrnect,c ,,.;--:"_?l :l't" loca..-ion of drains :;; - ;;,' I. "'ir:'3"'"1Ii;,"::" ; li:iTii"F"iii:^ : il ;ff :ffi : ;:il" ";": :: ;il :!';;;':,;:1.:i;1.:9". jrijil'F;F.i i:i: ::":tH. = ;it:' i":::::il;.: th3 suo_cirains i - -r v qs"' r,d:) ricen ccnstructcd. ttre f ocai;;;="-. ,,,.,i. . r*,ic:r "..;]iotifil'"lrlr.x*,::3i:;^:::,:i;, shorvn cn Fisu:e :-. ..1j.. 'rcbic:r "....a"iiri.'=Lit..]il-1??t:t ar-e also shorvn ";-Fi;;.':_li:-9iilano r,readc.,,,-s is about . ,, ,r"Il]l rnstallei in Lcrs :,- l, "is .:_li:-g,-ilnna r,t""J", .'.': 'rrcrL L jre sucqrain insttrrlei in Lcts z, o,-,.-'^._ i..=i-";;;";;': ;;":3:;_:. ii: I.:.:_e u"p. - -i[is ,"._.,y b.':': ::.:=:;;.'i,ll ii;, ;:;:r-:#: j:l ;i:l?F;f ",.jl.ll"x.I"oi,= ......- ^ 1,:_rber ri, ir:^ ! sr-iii'.,irene<-ltion by Robert Thoinpson in J r_. ,--.),rt ilre <iririrr Lc,. ,,arou: -ii';'.-;".o. ,] l'1,;- c-r. y sui-.,-1 i..'tins c.ri iecl fcr cn ih; pra-1-i:t 1?"s t-he scu--,r i rnc ot [,or e ? . ;'tt'--t:I pJ'an of Fi-1 :ng :l :. ;,, = . i"i" t l.?::, ;;'. ;:i. 1. ;::;, :1^ :.1=''; "i';1 "',lI. oi3l, !,, f t "i,.,-":::;.3:on i::C j_.iJtes rhet thesc-.lY' --t- , '! 5. Iir. TobJ ':''' L:rck of a piannacr <,,.i-\^ Fa i - -..-:""n . \tero not- insta rled, ;::, ;i,,;l: ;i:i;iii:"::':r, lit;:ii:l ::":* ff:;;e;jijj;:"1 a pianned subCr.rin systen in the or- l.nsta ILed. tate;.ient in tl_re 1978 ","-_ :.".?"9 filing rnay be report l;;;.:i::: t;;.. ;.;;.'ni',.liit'iJo"|""" rePort .r'u. "'"-JJ"i" .'i"ll'ro;rs, hc..,.,eve::, cv.i crrrnr,., ^-.^::f"terec.. " Thc current :.::):tllrfua"'fiov ,;:l:: j"',., ;;,;"':;;:"'31,tI""1.":":::::lierec ' . " rhc current :';:):llrface fro..r. ! v re\:ris(i r-xEenslve aroas of scepage or illi, rl!..n1";o""lo*"r1"::^l":i: lI-*u., and Assocj.ares was :l,r I of the yca:- , ----- irvr'\ iJy \'nen and.Associ.ates rras done .,r:ace _rio* ;;;;;.::" :I:l:.1:-the concru"i""_ii.I-ii..ro lil::l:.::,'i; J;;;.::" :;:.':;:.1:" concrusio" a;;;-ii.lil "" .=:::11 i nc j.c,rre f nat trre snri n^ ^ j":-?f the current conditions r!r.,r,.._-: _ r.r-.,w e._.:r.scs. cbservari.o.:. of .nu_"urioii li".o.il .''' i i ;..l.lii'.]r' !r.'15i.' l;. : o:l:?^ ;l l-lo . v"o i """a i'J r""s are "' . i. ". * J ii -.i i i r.'."';.' i;, ; oii:3. "i" Ii:, J:l:. ";;. tii "* ;: ,lt:" "i ;j.' i:,"ii 3jril""5::;i:::^:"ll: ::lofr=. incrucre descriprions of the '-::.^i,'J' scl I s . ,.- . 'l i1 Dt:trtOf C eneottnt-cred and t-- ssoLr r.F r/rr-r.\ri i -. !r^ _ _ he -georogy of the area ::3"::^^t:'.j-1"-:ooulai*-iIii";; ;:;.lii^;, T:, leolcgy .-,nd spcc j fic h.riirri a""ig""iiJni of soil 't, ^ i;;lll;::..:;il; ;:-?jii.:::'T,1.":,..1o u'ou ;mav be sumnarizc.d in ':1,',..tVr,1 i, rrric:( rn3r)t I,: gf .i;;.-;::^:":;:.1:lI ;:ffi:;::.roj...".;;:]n1 ".;rte:-iat :one .2o, t_c'Loui in oep:h _.r,-,ir.iyin9 thc - ')rr,' rrrrrlrocf:. .fht soi t ,nn,.,i io g=r,"ralf i, "o.rri "r.s of a san,ly, Proj Page IVo r9 1845. ool iiiiirrlJrli,ii.tl-t:iT:.I:g eravels. to bourder size rock rrasmenrs.gra<iu.rrry ;;;;--- rntrltrates into ttr" ""ii-iorrii"'' ancr nigrares Ir:q" ir6""i".*J:;:ii:i::;" ;i;.::*;"i;ii6,:j"*: ::i:$j;.e very sr'rduallv throuqh,'^s'riie-;;";;";;., l., :iglificanf-portion of rhis ;:ii::;3-: i:;:,.the.soi1 iur'.;-;no misrJtes aon,l tn. mountain *rrouehout*.iJ-""ir"i,,rtn:";.,:.f;r'.}"1,.:"ttJ;;;-.;*#nry sattrrat_eJ nave a Iimited ti necessary to. u'allt'iit=iui'iiii, -i*"r months' since-the soils areas t.-,.ho., ^__ ursror;;-;i;;ri"..:;:ii.u::".o*t: t_":l:a -"i iiii-r" :r :: i: ii:i";r i:d: li:, F":;*i;: il, *r,::,:::, oii:'"::ff ;j?' " or springs simol w , t = o i u _. i - " Jr. r,": J, i::"1"; :. " i ". - r i l;. ;H*' : :" =: " :: l;., k;r*: :il: l:, The condition discussed in th r:t t u r-d.L to the ar :n::. lo "ou,.,."iiul:' .'fd 'u'rr-"o,lii:::-ii]::"5:'::ir'in"tXo"t";1tt" ;;. 5ir" Ii":li" ;:n;i:":";:; ::"3'::;:;x ji4" ii'*ii:ii:1":' i#*;,f "":,1.'iil;;::*ii-tf l#llF;tiJ{l5iiiir;F' : ; : : : : ; ; ;,' - ='- l, ii i" J " flJ' i i' ii, n' "::,' ;. t*" j:i"': "u t " i: :i r: i: ..,.iili"i3::';i:::_i:reviousry icenriried in r_he Hi< .; =,. : i:'l t = ;:t'i" : "i,, :iir i', l iiti" ;ii.i t;q';i" l:i iili ,'l:3 il".., js+,i-iiiL5s i.ili: r)r:L:!nri- r .^::,-] l1rage nesr F!ling :1, clp^,-t., - \ , 1 i :; r ;" j$ff tii*'i:f r::j, J,.1:113i ';ii* i: t+r* :l*i. ) M rr ci sreep cur is opnn"J. __*". / Proj. No. 1845.0O1 t,age 20 V. EXTSTTI,IG SURFACE DRATNAGE CONDTTIONS The h!s16riq ::::_":.d-;;";i;r:::":i:,i;;i"??: pattern for the study area dra ina ge ba s i n s trtt"" Jr,Jrt'"i;. tj.:Y^:i th minirnum concentrarion of pat i.ern i. "i.Jrihrougllout the rna jority. ot ii,""'"i-i". This drain.rqe :: 1 y- :": - i" ;;"-; . ;I",';jr':";.:l,.l".ntl-".t":t_1en "i -.Jp" llr:; l",i:S "5;" :r,- o "u ri I;;' ;:j;iil, :i;:i:U"${iifi^::iii;= i ", : i;f i:j;r ;:i*r J :; i :n :i;ri;iii:.ii^ -:i$l : il"; l: r. ""* :d ",l tn" ; r and controlling erosion. ..,.^-, l.?:,.:ructio;r of rhe roa,l syste ju:cirvisions has servci ',c intercel. il, th:. Higirland Meadows l i..i, it :;.."';;l -'::. "" J " ;;' ;":;l:"::".3' i i l: :. ::::l ;:-:'ii;:.: "': ,,: ! '.p::e ra. i"", ;:; ";;:: t"tr!"1":::^1.^f "log;;;;;.";..e :i..lji:. ir#.1*y#;i-i;iii. i=:"t"";"i:?;:;:* ;::,"""" ;:;;, , .,, ..n. "o::ff =: :.i" ii; ti{;:i: ::li:".5}i::. i, ilr1 ;; u f,:*." "; - '1,,,, - ro. -i "i ; -,,1J;;.:Jt,,:*:,: :;ff ' ::'ii":"1 ):::';i::ilr;i:;"".f::; ci co acres,uniro fn"-ni;li.iiti"3r"r_l:"";":::;Xi.l;Ji;:;;. . ,:]-.1="if j.c rir-aina_:e facit. jties : :l:: \"'iriase r'rest irri."-ii -lii-'"t: constructcd . . ;;:ac snowi";tr,L-1t:::-;r P,rat. A i "-1ss, , 2, ::"lt^::tt ot .i ':'r ,"1.':.''-o."1!"]!o.;i; ;::tinff'";::.1: i.a?;".; : concour ;:,.. . '.;;,j''-:''1".".'a" - .rl" t",]ii^nv. 'oti"iJ" ii'I:"st'ruct:on or ,i.,n ;. ?. .n. "..ui.l;'r:1,j:l"i:i:ii:;:!;"::liI;ff"li:ii"H:'; ;;,:l - s^ :, ;::.;: | ;i i i,' i'; ;'; ffi , i.liH; :i", it i";:" [Til3,]'n i"';,", : a..,, -,.,.-l 'Jng- the rc r : r ; : . : : ; . : ii i : r " j:,t:iji.:",;, i i#:irii *$:,. i,'::;' ':t"rt;;;i::. cn rne prerj-rninar" ;l'::" e'Lininated t-wo of ti,,r-" ;*;r:i,,;t:'tn;: ;il.fiilll,it;ff"ki::'i:::.:i:*:.r; r .-.. ". =., : I l. = I i : :: o _, ;ili: i; ii.. ii*' :?i. Il =.,1:, : X;ij': iI j: * t". " [:l :i,,iil:ii:;:: "o""t.u"i"a-ii"Hishrand "".a.,]l' Filins #2 has il:. r ; i ; ;ijff j.. ::j :: : : ; :*:rr ;",;i* tii*:ii:i:: i'rfj::r= ii." Proj. No. Ig45.OOr Page 21 ?he affect of rre hi srori" io,,i.""T::..t'l:;:?.i:l:rttr,"X.rl."ji"injt".,fi;J:?.j:"- ro"vs ' Areas which *.ru. pio''i;;;iy sub jict to a -iJrotivery smalr rainase basin ro repleni;;-;;;;;;loun,t flows- experience continuar l"'ir'lS" ru":;i;3;.T"loll., :::::i;:- !!. appear rvhere they rvere nor rev iou s I y evid en : - erevious iy ;.,i:1i:#SI" "lii.o:::il"'ff:.llr."o,,o ;.::S:;.':::t.?"^ti::::. ^_I.l:-"1nli,l.,". j.on or rrow to the ntersecrion of A).pine orive ;;;-;il;;";;1,":.#;"y.:; ,lli, o" .::.:j:ii",:3" ji;.::. ;:" l:; :*jF::_ i"i- i.,o I illll "iouu subs rades :'e continuously saturatecl *i.ran -.o.. r\..t- ldlrusrqe' Road- subgrades o:rs secrio," or ni.r r "iJ.-.'";;;;,;":ii)::.3'l:"::;.t:.:i:""i:?j::".ro*'s. This may contribute-i"-iiri srope instabilirv. gduceo orveyed .0.: rii:-,,;"r;: i]t'riri' and iac3e i,'est Filings rnprovc.J a n<!of f ]oi". are snrall thc sides of thrr adequate to carry the flow f rorn the through Vaj-l Villaqe ruled our_ due to iack geologic hazard of li:uj""::"::"::li^:^'1.:g_:: surrece drainase sy,stcn has I l" ^, " !' ji': "S ;: i ::n :. : ;:: : :T; - ;; ;;, ;; ";:i:'":Ii:;l .l: :.0,1.., I u.t. iro I..i ll^t ln, : li :!: ;.' I;;;: l. ;;';. : i i : :n ", il::i 1 i -^^a_r-1 aionq thei!. south l"unciii. -..r vcrrr vrlrag,, irest tc the iinot ,, ..,,, r 'aF+ r,-.r -- rr ras been ints'reepted i I . : i: i " o :i : I :, :^,: l: ._ : I ! l, " J ii " "u:" ii'r, ii i.'l,_l .,u" ll tc the sinsle curverr under v"i"""i il;; ji.il:.f 3n'i'y scattc:-cc secticns cf 'roadside iitch exist t_hrotrgh the rru:"1 ViL rage riest subiivisio"; ;;; few cuiverts exist beneath :.:i:vcways. 'i\^,o culverr-s, u, iriu"trat.ed _on ii!uio :, c.rrry f row '-rccuinulated in che critches u""""ti- core creek orive. lrost c3 f cas ....",* i.,ii..li, ;.li"i i^::i:_..44.:k - ;;:. :," or al pine Dr j. ve to oore .i t i sl sl 11 | ii":';" "o'3:";:i;: :::j:i::.F!^;i:ii: ;;.i':iff :::::' :! 3"Ii,".. ,, i,", p..,,,ie"j- i?-L."' ;;:'j:;.;"ori3;"".11::_"j] --:,111.=. rnsra i reo al .;i;;;;;" . "^il;tch sysien is e gu.:ntilies .i.i0"3""1"1,';.i"1:.?'':3, :.:::l " J , ' po u oi "l,u;;':: '; i;;;ji;:: :: :::o^:?1 s"tJ..i.J-=i"ir'."I ;;;i;=.i"':"8.: lo*s io .i,"-".r""i;;';;;:.;;'i"?3""I1:i"":i;: Ccnsi.deration has ceen given t_o br:-n,cinq :si-+ i aq ^€ ^c _ . r1.,.i19 lJo. r. .Inis alternative has been .-.'^"asenents, tooograpiric con=taoi.lr-" - -1 hA f r.'"1e ur>oer p"i.i";-Ji'5rr'i"g'"il;:'i constraints, and th,,o .--, '.'.-ruiveri sircuici b. cxt€.nd!=c aiong _the 10t line betrrecn Lots 47 . !;,;: |ir.li..i"i":;:;in_".101"."'iepr rJ.ow ri".-ii," curverr benear.h .-- llows for the r0 year-(roc probabili.ty) and the 100 year (rs l::;::iit:{1.,:.::::" period srorir Lrvents hlve been carcurar-sn !y :,^ .,',,,, ::n3Lneertng I\SsOCiateS, fnC. .tnd ".re StrOWn on FigUfe 3.'..".^-10y" '/ere ce rcr rated utirizing the soil con""..ruaion service .,, -.ly .or rainf aI I derived events anrl snov,rme l t- f t6ss ,.,u"""rdiod b.rsc(r on g.rug.l recorrr an.lysis ir. -!i,.-iigh mount.ri. l:;:''Y"'r84s'ool area of Colorado ceologicar surve\, and the procedurr the rJnired state. puuricaii;;-G,": presented in the u.s. r shorvs the calcui_:.Tt t,-"Jri'.ll:';i;.:"fi":i;:'.1.v or Froods in carcuratJJ-t;-;:;i.::3 i|B";::I:fJl:-""tJit".'J'.uiu"'.'l"tu";l li:'." l- .The surface rrrnotf control I i:'iiiii* ;; ;;:;:i::ff . x:, jit* :ir j::' ii, ;$:::" t:'",:r.:iil:;t: il::.t3;:i|]" ;:,llstoric ci"i""i,' rlol''s and return, tro*.'JJ'il;t"; I con s r r u c t i o., o i"J::i " :j*: ii;if i: fii!: ir, "i":13*I;;;";; :;; !0" o" li;iii:r:;":':lt::::ii:"'io-,,*i',lo'nl=",.'l:;:nnoJ:t.t""ijj"i."iu!". r and il';ti=, it*#;;,;iihf ti, li*r'*i'. iii; ::; t": i^;",";:;;:ii:'r.. | ; i" ; I'.', .r;'J. " ..#. ; *; ;i !: id;" if " iiii'i:;i: :i: :$'i, iii:im' | ..;;,;' ii ini' lX!",,:: ll"::ol;. #:. ::l l; ;:" 1* i::::.i:ll, ii,ujJo."' " ',',;::-=":i^:i::"1;':;"';ffi'?:ii:l:" i. i]?': has occured in Hishranci ....a,rua as an outl-€ . ; r i i;' : = . i l" 0","; iiri i: i til, i:"" I : ":i : l, ;ffi . ;: :;'i i -iiip: i' " i,, ;:: : ;.;;j, :i:;:ri';i!:, ;i: ;:::;:"i!i.;inj f t" :; j i. :: ;:jl , l: ::_ i.i" ='li -.,'i.' 13 ::.: ";;":" ::,., .:: r ! i";:".':i; veriioi,.._ Rcad ...._ ::' c:<posad .,o -i. -i; ;;;';;uloil.t:.1:: c b.nsati u.i*".i'i"oa -_l: r::ea:s ro .1...1 .,,,i.' ! l, i ":" ;!:j:,;;N:, l;gi;t j;:";' ; ;"':;;l' ;'l:,' i"';' -li;r ; 1 $i : *: : ;. ;:;*: i : : ;n tJ+j* 1g fu il - : i; : : i " ;ii!, :'ii,. : ": ".., ..,.,ioir.,i'",1 0*?i. Road to core creek. -";;;;;;, fr.: no.ood rrom tl l:i;i::::t ;;;; i"':.1;. tln".n'lo"::j'"*.l Panch i"uiiJT=f:: Iff'n:3d ;.:^":ltsron was "r,"'.ui-o."r;i;";:i";^-3^u location "t eil:.ofI il"'i"n ;::;.l:.':::I:i;"==":;: ::'Iiij";;jrl::==t on'r," -p'I ii:'' i i : i;.#i;;; irnprovemen. = ;;;;i:e;"*:;."i:"i$ii.:::ii'ii.. illi 'ri"' 184s . o0r , ur. sLoPE sTABrLr.rY I The Lincoln I /#iffi *?Filitr*ilii"'*'#iili,ii=,:i.:i:il""ii.""= ffi*$l*l1+git***{*ffi" ; l : ; l ; j' :il 1: ;:: r i " o l lni"JJn' :.';ll " n op" o n j -o",,IJi ::;.:::I. .li," u The prima : rit dcn.: by ciloL':: l'. ; ::: j, ; : ; i ; " :;, ; i " ^ i: : : :.1 i " 3.J:,:. o: . : :* :.. : i, :l .* ". ) The ma jo:-i sucstantt. ;"^::' *-he tiiqhlar a r e, o c a . "'..' 5j ;;"i::" :i:iff "$::i;iJ ::.;:i: " riii, r i!, l,': ) l'1os'- are.rs ,.,r,.' 6,rr--: - - !v rtrs'(l- stable soiis s ubs ui.- f ,-r c ; .1i3r, ".l.lii.".t. to s J. ope in s t a b i r i ty .r. r exces s r) :?!: r0_i4, 22_2t), rB, 3s.r..ail Vr l_l-ac ,;: 1 r as J -;;:: -l'::l- i' iii,,;',-i.lt^ 3l; ll ; " *.i: - lS i,lou3?r'" :.'"::i:" :;!''.t;'.' ='; " ;3;. t ";i, r., i_t", :;; :";:;i., : : i:i;: ;::, :"o.a r ".iI! " ;;,';.;i;" n"r.rrrii. 1: :;i. : ^' inl'oi"vi siors cr ;:: : :. j3::+l ll. :.""injiiin;n;""jin;":; Ti:;;:;isiir"t '4 ) i.ra "Iopes ..t'-hroush ro il'i.if"uiii:t"",i11:t::.,',r the back or Lois .11 I:;fiiril"5:tt::, u"' i-=^,,ju*-rj'jt Piline ::o' z and Lots ,rr, ai-"i;' o, l;;.=r.i"iriiilji;i:: :":i:;o":'.;::a .;;"."moniror:ed for sjgls of fairuJ::a tr, stourJ'ie care,futly 5) il*:^"lo?. movemenr is eyiden r.a noe Dri ve :i: :* ",;5":::if: li; ";l;;:ij:"* llii ry* :f i:fi t:, ti.'r",,o,lidu ;;;;;l;"ii'j;:::.t:::"*ll;:;*ji:' I I Proj. No. l.g45.Oor Page 24 6) reduce future movement to acceptable linrits, except at the Alpine Drive srditchback.- R;;;al ancl recompaction of the filr in rhe switchback area-i'l'ro"o^.ended al0ng with subsurface drainage rn".=rrro"] Tir e magnitude of movement of orher fill stofie" ,to"iJ-ie monj.tored by setting i:::ii:;""1"i:::,inrth; ;;;uJit ana "u'.,"vinj-ii.ii Cut slope fa.ilures in th,: form of slumps or slides are evj.dent ar thc Alpine Oii".-i*itchback, the Sequoia Drir,.e cul-de-sac, the 1:lg. ori".Zi"quoia Drive inteisection and on Lot 22, vail Virtase w"si-rlring uo. i. -..;;;;"s ground t?ater is eviCent in ejch f"if u.". are<1 . FoIior..iing the Lnstallation of arca l*iae suOCiainage facilities, these :::H.;i:"iroi repairec and monitoiea rci-e.,,iJL'.o or rera i n i ns,,u i, = "i:*:i;r::; :; l. =.i,llil.;i ":;.,::jiii, "f" r,vilrage lfest Filing N6i i-i;-treatee by a separate reporr. Significant poi.tions of ;iighland l,teaCows, Highland Meadows ;2 and Hylanci park ar.e _.riai -;;;;s defined by Lincorn Devore as possible so-r.iii".ti""-zones v,.hich are a fo:-m of soil c.eep' only a p"rti""-li"aiu ..to. -riJ"--"iua.ui.r,.,g" calrec for on the construction plans has .een instar.r.e,l in Lhis ai:ec-r . The exi st i"g ii"Iuiied sirsrem may not- be i;;ii:]."r to a!.rc_-st this area wic.le rnovemenr to accep+-able The ciegrees of stabj i ity of all of :h.: s-,i:c11.; erea j_s l:scusseC in the '.ir:o1:i :"f,"io i:t,rroit-. ?he stability conditlcn of vj.rtually r11 slopes riray be sunnarrzed as foll-orvs_: existing s topes and moderate lreight- cut areas at slopes f ""='tfron L t/Z:l and moderate height fill areas.at srtpes r.=u-than r r/2:L will rernain gcnerally stable if exceis suUsurface fLoiy does noc ex j-st. This staternent is cased on tne .trssumpti.on of I)rogez' rni tial construc+_ion. Excess - subsurfale flow rnay renCer any of the above .""tio"=J slopes unstable. The existing near ve:.tical cut slopes on Alpine Drive and Sierra Tr..ril in Vail vif.fage w.li oifirrg I shoul<! oe ccnsidereci u'st'-rbre. cort6"t irr! -o"tion should be taken :.:":i::ing of .u.l_i:e t-rre siopes Uaex aL 2t 1 and/or Lnstarlins retaining v;aIrs. i'o "rope.-.i;;9-;i;ine prive are of p.rrticular eoncern, as they exist in in aiea n.tppea as metastable by Lincol,n Devore. 7) t :: .:. , { L 'jl .rVl iI33'rI"' 1B4s'oo1 fl) A system of *z ina ,r.11 .-"19:rdrains throu_ghou*,. Higlrland Meadolvs Firino ritrr co,nji!.Yrrrase lJest Fiting r is;;;;;.;l High rand :rtooerl9- the - underdrai onry r.rirJ .ni?'= .u"a uJJii;-"':-:v"f:l r'"p"";o""?;'"to"n +-hroug:1out sa=iu druir;-;;;;.-?tt.addit-ionar clrains. Nor inciivirlual o,t?- 1fea, b.rt i;;"co' lntercept subsur"'ece fiJw rhar ari iur-i-'r.ror"g'".uJ."i;:" -^li :;ilt ";".:".:;:i::,,'j;: s.ui:c:.rin ;;:;H"3J'?ili'lirol_l3"n""tuJ-.o-*rl. centra systems be-connecfJo -ao".nt.t'^:::t anci site ar.:inafe--- i iiiii= tir liii :; il {: "i:,::i"* +i t- : :f * i, i :iill'.re_ente.r the irrustraauc o,9r?lncr w.rtei-;;:;"o on the grou;rd _surface to e* i .,. i,,! -; ;. "i.::H::li. ;;i; lii : i :i. ;" :;:itr;r.i, ;i::., i" l2 A surface dra i neq roacside -aii"i"!"1"";i:i:, ::":- ::::.j9" surf:ce runoff rOaCside ditches-.- "r er=rr: Lnac renoves surf recoirnended . "o. -.o_I_rlinize sa curat ion of rcco::rnended . Thi -"+--:..'42.s, 5d curat ion of road f ills cne subdrui, .=,,r"ri-"I::.:, rvj_11 born serve ds a n.rr;^the subdruin ,ysl* srJeel;i rvr'lt bo.lh serve u= " poition ' ". "'* u' J Ji " t i J t' r' iI, il-d. .t I "., i i: :.t -" : - t,, no i e - J y ; r # : rh e fror l3 portion of ;; ; il:; : ? ;i i: ::: I I I ::' : l: -' ii; ;i.";. io"'3f '" iJ.il;il;;:;iiff,.J,,e e"so. i;;;; ;i;";:.i:.;-ii3..,ll ;;:r;::!""ended Facilrties Sor:rc lccal lzeC sIur,,r::i h., jhr __st j.t t be c:::pecre.l"':11:n anri 14r7si : i-: r o* = "".;;;;;:. ";;;;i3:. jjj: : i?" :i ";' :?" ini"Sxl!,u i,,;il: ;:i;'i.;::ll'^'n"n-uii ;"I.;; .J";:.Ii]'.:i::i":,:::; '*.:r.r-i-<i "" .-,.i."" i,..ii"i"", ==I:;.i; :"::- _ il"_". -o".,]r.""""" :E;. ;',;:;;i ;;:.":;;:;.:l::::"1::r:^ii:"ff '..uj,l "u"n ii;!:;:i lif oj;: !. i; ii: : i;ilt: j, ;: $;. : *;i;. ;;" " "' : .l " 5' i I i . I : ? ; ; . _ : I i . " i " " J i i " g'' i ii*'.u nt,t = " I :o" i :, . :". ini.i I ". l;" t a)z U) o UJ (, =(r o cc, fl 3 ct c F \r$o q |,)rt @ Cr) |'U tr f,g lt -\'.'. /;q- -Jzzi .'4 :i: /l I i Wm W t),", t',1t, \|fl fl(t;;d ir\\\=-= ,r& .N ft{l iii\\ $i:\i /tl ///, t# ,D -'t !t. t I ,l i l DRAINAGE AND SLOPE STABILITY ANALYSIS HIGHLAfUD MEADOW$ AND I I VAIL VILLAGE WEST SUtsDIVISIONS Developed for the Town of Vail, Colorado I -r|i' i Job No. frugust 1845.OO 1 17, 1982 (:1...\\'(:otil, llN(;lNttllltl N(; .\ss()clATli.s. l.\(1. , sL'I'l'li ?()7 \'11.1,.,\(;tl Fl-AZl\ (; l.liN\l'Ool) SI>ltl.\..(;S, C() 8t(ioi "a:cf.fk.:rf..**_ DRAr NAcUI8"il33"#ll3*3'IIDANALYSO VAIL VILLAGE WEST SUBDIVISIONS TABLE OF CONTENTS . POCKET AT BACK PAGES { I. SUMI'IARY ... L-7 II. BACKGROUND ... 8-15 rrr. .pREvrous sorls AND GEoLocrcAL REpoRTs.. l6..Itl ' r rv. ExrsrrNc SUBSURFACE DRATNAGE coNDrrrolls.lg-20 V. EXISTTNG SURFACE DRAINAGE CONDITIONS.. .. 2L-23 VI. SLOPE STABILITY 2!,-26 LIST OF FIGURES . . . .. POCKET AT BACK ,FIGURE I FIGURD 2 .t FIGURE 3 FIGURE 4 L . FIGURE 5 27 2i:^ 29 ' APPENDIX REPORT ON GEOLOGIC HAZARDS INVESTIGATION AND SUBDIVISIUN EVALUATION, HIGHLAIJD I,,IEADOVIS SUBDIVISIONS AND VAIL VILLAGE T.]EST, FTLING I & 2 BY LINCOLN DEVORE. { Proj. no. rO.oor Page I DRAINAGE A}ID SLOPE STABILITY ANALYSIS HIGHLAND I'IEADOI{S SUBDIVISIONS . AND VAIL VILLAGE WEST SUBDIVISIONS SUI4,IIARY AND RECOI4MENQ4qIoNS 'r. A. B. Basis of Report This report has been prepared under. contract to the Tovrn of Vail to'evaluate the current subdivision layouts, identify critical problem areas, verify construction of planned drainage -facilities, identify areas of possible high density_ housin6, conduct additional geologic investigation and provide a cost-estimate of recommended improvements for Highland Meadows, Highland Meadows Filing No. 2, Vail Village west Filing No. 1 and VaiI Vitl-age I'lest Filing No. 2. Extensive soils and geotechnical investigations were completed on the Highland Meadows Subdivisions as a Part "i iit.it platting durinq the period extending from 1972 through lg7B. No soils or geotechnical investigations have been located covering the Vail Village west subdivisions' Lincoln Devore, soils and GeOteChnical Engineers, have prepared the Preliminary Report on Geologic Hazards Investigations and Subdivision Sviluation contiined in the Appendix to this report as a consultant to Claycornb Engineering Associates, Inc. The Lincoln DeVore report is I compilation of previous available studies and independeirt evaluations on the part of Lincoln DeVore. Recommended Surface and Subsurface drainage improvements and slope stabilization measures are illustrated on claycomb Engineering Associates Figure l, Existing and Recommended Facilities. The Preliminary Geologic Hazard l4ap by Lincoln.Devore illustrates that a substantial nur.rber of lots in the undeveloped portion of VaiI Village West Filing No. 1 are in a metastable area where extreme caution should be taken r,rhen units are constructecl . Very thoroughly designed nitigation rileasures will be necessary for th."" tols w5ich should follow detailed geo- technical investigations of. each builcling. The nearly vertical road cuts on elpine Drive aird Sierra Trail should be cut back at shallower slopes and/or retaining vralls installed. Due to the metastable condition of nruch of this'area, the design of the siope cut and/or vralls should be very thorough, and preceded by detailed geotechnic studies. o No. I Proj . Page 2 845.00r The majority of the developed lots in VaiI Village West are on stable areas as indicated on the Lincoln Devore maps. Surface drainage improvennents should consist of roadside ditches, curb and gutter, or paved swales along the roads. The anticipated repav-i-ng of Gore Creek Drive should consist of total pavement section reconstruction' as the current pavement exhibits characteristics of total base failure. Hveem tests are currently being conducted by Lincoln Devore for pavennent design purposes. Subsurface drainage improvements are reconmended throughout the portions of the Filing that are designated as metastable, vritb an outfall to Gore Creek. These drains vrill not, in ttremselves, provide stability for the area, but wiII provide a positive outfall for subsequenL individual unit drains and retaining wall drains, while generally removing excess subsurface florv. The landslide on Lot 22, Vail Village West Filing No. 1 (Bitetto Lot) clearly illustrates the hazards associated with construction in the area when proper precaution related to slope stability are not observed. Referral to the Lincoln DeVore Hazard Map illustrates that Lot 22 ts actually in one' of the lower hazard zones. VaiI Vi}laqe I^lest Filinq No. 2 The Preliminary Geologiq HazarC l'lap by Lincoln Devore illustrates that a portion of Lots 4L"43 antl 45 through 50 are in a high hazard zone. Virtually all of Lot 44 is in the high hazard zone. The remaining lots are in a 1ow hazard zone. Surface drainage facilities are recommended to properly drain Gore Creek Drive, consisting of roadside ditches, curb and gutter, or paved swales. The anticipated repairing of Gore Creek Drive should consist of total pavement replacement. Construction on any lot near +-ho netastable slope shottl-d be precedeci by a detailed geotechnical study and include thorough mitigating measures. Undercutting of the metastable slope could cause slides extending into the subdivisions above VaiL Village vJest Filing No. 2. D. Proj. No- 1845.00I Page 3 Hiqhland l-ieadows several geotechnical studies have been completed on the "rrUai.ririon=. These studies reconrnended caution in a"v.rop*.nt of the area, identifying stable, metastable, ""a-tiStt hazard "or,.". Subclrainlge systems were recommended [y-""ri"in of the studies and considered as a condition o? upptottal by the Colorado State Geologist and Eagle CountY only a portion of the subsurface drainage'system shovrn on ine- pr"iiminary plan and the Construction Plans has been installed at this time. The installed system bas ie*",r"a part of the subsurface flow and reduced the areas oi in=talility to sorne extent. It is questionnable li lf-," "y"t.^- installed is suf ficient to deal with the area wide problems. Portions of the building areas (that is, areas not identified as open =p."6) aPpear to impinge on high hazard zones. Reference to'the Linboln DeVore Hazard l'1ap wilI illustrate the areas. It is recommended that the area wide subdrains be installed in accordance with the original plans under the direction -i a neqistered Geotechnicil Enginttr' Consideration should 6e given to expanding the oPen space -designation on those lots where the i-tigtt tir.rd zone extends outside the present oPen sPace area. Specific improvements sr-rch a-s reoPenr-nt the-rnlet to the ctr].ver:t on Vermont Road Lretween Tracts B and C shoulcl a'f so be accomnlished' n5-frrrilt clrar'rin95 shor-rLc'l' be prepargd gf the subdrains in uighland l,ieadows and easements o!:+-a-ined- for the subcirains t6 prbvent.Luil6ing operations cutting the subdrai n .l rnes.' liighland l,leadows, Filing l'lo. 2 General cut-slope instability characterized by slumps and "iiJlo in the "if"".a cut sl6pes is evident throughout the- - - second f iling "i'ui-gttf"nd I'teabows' All of the slurnp,and slide areas are in locations where sub-surface flovr is evident at free flowing r.+ater (sprinqs) or saturated soil during the spring of the Year. The soils and geological reports prepared-during the preliminary Ph;;;;-6i-iigrtrana.tleiaovts Piling #2 noted that futl "rof.t-tna oin"t conitruction areas courd only be considered stable when dry. Cautions about possible failures due to instability of cut and fill slopes were inclicatecl if the areas were saturated' The only differencc F o ,1 t Proj. No Page 4 84s.001 between the individual reports is in the degree of the verbage indicating the extent of the hazards vrhen soils are exposed to excess moisture. The surface drainage plan for the second filing has tended to accentuate the subsurface drainage conditions since the surface drainage pattern criss-crosses the slope as drainage is carried in the roadside ditches. This criss-crossing effect has tended to prolong the exposure of surface runoff to the subsoil, allowing rncre infiltration and thereby increasing the available ground water' In ad<lition, the surface drainage pattern has concentrated flows into specific areas whil-e the natural drainage pattern consisted for the most part of diffuse overland flow directly to Gore Creek. In parti.cular, at the intersection of Tahoe Dri-ve and Alpine Drive, directly above the Bitetto property' being Loiu 22, Vail Village West Filing ii1, the drainage area has beetr increased from a historic basin of less than five acres, to a present drainage basin of approximately 24 acres Very few subsurface drainage fac:-Iities were installe<-r as a part of the subdivision construction. OnIy a very small portion of the subdrainage for Lots 7 & I illustrated on the Preliminary Plan was actually installed. The facilities installed \{ere at the location of active springs encountered during construction. It is our opinion, following review of the available soils and geological information, reviet^r of the construction draw:-ngs for the subdivisions, and site observations, that virtually aI1 areas presently indicating instabj-lity can be arrested by proper drainage of both the surface and subsurface areas followed by corrective action such as recompaction of filIs or construction of retaining wa11s. There is no evidence of extensive very recent landside areas within the subdivisions. The available evidence indicaLes that with proper area r.ride drainage of both the surface and subsurface, development of the rnajority of the lots wilt be possible vTith a degree of risk whi"n is normally associated with typical mountainside development. Lots 7, B & 9 are particulary impacted by subsurface drainage at this time and installation of an area subdrain is imperative, along witl'r very thorough individual lot geotechnical analysis, if these lots are to be developed. Lots I through 6 are located partially in a high hazard zone. In several insLances, the building envelope Proj. rolurs.ool Page 5 F. defined on the record plat extends into the area defined as high hazard on LincoLn De\torc's Preliminary Geologic Hazard Zone. In fact, these envelopes overlap, or in the case of Lot 4 are totally covered by. areas that were illustrated as high hazard zones on the original soils and geotechnical reports for tire development. It is recommended that these lots be reviewed by the Town to determine if the currently defined buiJ-ding envelopes adequateJ.], refLect the geologic hazards of the area- Highland Park Highland Park is a resubdivision of Lots 26 through 42 of Highland I'leadows. It is in an area that the original Geotechnical Engineer for the llighland Meadows Area, Robert Thompson, recommended against developing- Subsequent soils and geologic reports were more favorable to the area, with the result that platting of that portion of Highland }leadows rvas approved by Eagle County. The replat submittal of the area refers to the previous Geologic Reports and states that h'uilding areas are outside the high hazard zones. This replat was processed through the Torvn of Vail. Comparison of the Highland Park buildinq layout on the Preliminary PIan to the Lincoln DeVore Hazard Map clearly illustiates those units that are planned, or in some cases under construction, in high hazard zones- The Town should consider submitting the Highland Park layout to the original soils and Geotechnical Engi-neers for review and comment. Based on the avaitable information, the basis for approval by the Town of the proposed proiect may have been somewhat flulty. It certainly appears that re-siting of certain units is apf-:ropriate. and possibly elimination of some units if suitlble lower hazard locations are not available. A suitable surface drainage outfall from the west end of Vermont Road must also be developed. Area lfide Considerations The Landslide on the Bitetto property, Lot 22, YaiL Village west Filing 1, clearly illustrates the potential for slope failures in evin moderate-hazarcl zones if construction does not follow the reconunendations of qualified Geotechnj-cal Engineers ' G. H. , Pro j. "o.Qrou. out page 6 The provisj.ons of ordinance 16, Series of 1982 should continue to be applied to all lots in the study area. In addition, a requirement should be imposed on all future development that individual lot geotechnical reports be prepared based on analysis done during the spring of the year or the conditions of fully saturated soils should be considered for design standards. Subdrains should be reguired for all buildings regardless of conditions at the time of .the soils analysis. It r,ray also be appropriate to revise the wor:ding of the ordinance to altovr ior aesigns that "float" '*'ith laterial movement as well as those that lrithstand laterial load. rf the Town desires to consider dqnsity transfers from the present lot configuration to a group of multi-family sites,a map can be developed which illustrates t-he progressive degree of hazard on the site. Based on this analysis map,units could b. transferred from the highest hazard area to the lowest hazard areas. Another suggestion is that a convenance it-em or ordinance be enacted that requi.res alr purchases of lots to indicate thal they have been provided wittr copies of the geologic hazard reports and maps prior to pur-hase of the rots and are ar'rare of the degree of hazard to their partieurar 10t and subdivision. The following recommendations are macle to recluce the probability of future situations developing s.i,milar to those addressed by this report. I. A statement should be added verbage to be signed by the Engineer for the subdivision has revicwed the final ptat and f i ncls them in accor&an<:e recommen<lations. to the Final Plat- soils and Geotechnical to the effect that he and construct-ion plans $ri+_h his Simj-Iar analysis to this report may be appropriate for other portions of the Town of Vail. --frroi,rt,rallv a comprehensive hazard map .could be developed for the entire Torpn. The provisions of ordinance 16,Series of 1982 should. then be appJ.ieci to all. units located in moderate to high hazaicj zones. !!i H. Proj. "o.Qas.oor Page 7 3. An ordinance may be in order requiring purchases of property to indicate that they have reviewed.the trazlra reports and mapping applicable to a piece of propcrty, lot, or'unit. Hazard rePorts such as -aval.tt"ho and flood pJ-ain zones should be included as well as geologic. These report-s might be made available to potential purchases in a central Iocation by the Town of VaiI. 4. The reguirement tht soils and geoloqical .reports be bases on the results of tests conducted in the spring of the year, or projected to conditions of saturated soils, should be applied to all areas lthere aPProPria te . A combination of factors have influenced the above recommendations. The extremely high property values of both land and improvements in the Town of Vail means that very large -aollar losses may be associated with failures in hazard zones. Since purchasers of property are commonly from outside the Vail area, and often from outside the United'States. t-hey cannot be pxpected to be knowledgeable about the climate, geology, etc' . of the area. Full disclosure of the studies by qualified people should be made avail-able to them prior to the purchase of propertY. Qualification of this RePort The Town of VaiI should make it clear to all parties utili.zing this report that it is not an in-depth analysis of .l-ots on an individual basis' It is based, to a large extent, on previous vrork by other soils and Geological Engineers. NeiLher the Town or the Consultant team of Claycomb Engineering Associates and Lincoln DeVore can be responsible for indi-vidual lot conditions, the construct j-on previously designed and constructed by others, or the development of these properties. AII of the recommendations contained tet"j-.r should be viewed as just that - recommendations and not const-rued as a requirement- that the Town, or any other Party, construct the facilit.ies or follow the recommendations . l"i. No. l84s.ool Page 8 z' II. BACKGROUND A.Background of This Repoit this report has been prepared in conformance with a contract with the Town of Vail dated JuIy Z, LgB2, which included the following primary work items: a. evaluating the existing subdivision layouts,b. identifying the cpitical problem areas,c. verifying the construction of drainage facilities,d. identifying areas requiring additional drainage improvements, 9. identifying areas of possible high density housing,f. conducting additional geological investigations, S. preparing a report of the analysis,b. preparing a cost estimate of recommended improvements. The scope of work for this study was restricted primarily to Highland Meadows and Highland Meadows piling l{o. 2. An initial pretiminary Draft of the Report titled "Drainage and Slope Stability Analysis, Higirland Meadows subdivisions, " was submitted to the Town oi Vail on July 15,1982. The draft was intended to document initial concluiions and supply that information to i.nvolved parties such that they cotitd respond accordingly. .On July 27, ]-g€'2, a meeting was held at the Town of Vail Public Works Buitding to review the draft report. Those attending the meeting are noted below: John Eberle - Town of Vail BilI Andrews- Town of Vail Leroy Tobler - Contra Engineering (For Ralph Mock - Chen and Associates Jenna Kauer - For Tim Garton Elmer Claycomb - Claycomb Engineering Ernie Freggiaro - Claycomb nngineering Numerous items of additional information were made availabre to claycomb Engineering Associates at this meeting.Tle_-Primary outcome of the meeting \,vas a decision by the Town .?l_Y"ii-to expand the scope of llork to include VaiI village west Filings No. I & 2. fhe submittal dates for a draft version of the expanded report was set on August I0, LgA2. A l9viey meeting aaie of eugust 13 was also established, with rormaL submission to the Tohrn Councit on August lZ, 1982. KKBNA) Associates Associates t)"r. *". I84s.ool Page 9 Lincoln DeVore, Soils and Gcotechnical Engineers, have worked as a Consultant to Claycomb Engineering Associates in preparation of this report. . Thc following material was provided to Claycomb - Engineering for review prior to July B, L982'. i:l!i:,LT:3u::""::ffilil::';l li*=.:.'"i::;":i::' ""u - b. . Highland Meadows, construction plans, roads, \^/.a ter and sewer, Filing 2, as-brrilts, lO sheets, date of s-builts, 1-5-80, l-10-BO, L2-L6-79, prints. c. Mylar sepia, Elliott Ranch Subdivision Plat, sheet l. . d. Mylar sepia, Highland Meadows Fiting #2, Plat, 2 sheets. . e. I'lytar sepia, Resubdivision, Lots 29-40, VaiI Village' West #2, plat, I sheet t. Mylar sepia, tligh)-and Meadows, plat, 2 sheets. s. :il:ll":"pia, vail ViIIase i^test, Filins #2, plat 2 h. Mylar sepia, VaiI Villagc West, Filing *1, plat, I sheet i. Mylar sepia, Matterhorn Village, Filing #I, plat,l sheet. j. Sketch plan submittal, Highland Meadows *2. k. Letter report by Terra Task to Doug Bitetto, 3-5-82. I. Letter report by VJoodwar<i-Clyde, Consultants to Town of Vail, regarding tsitetto property dated 3-18-82.' m. Preliminary Engineering ceology .rnd Subsoil Investigation, Highland Meadows Subdivision, Filing *2 by Chen and Associates, June 30, 1978. The following items were received by Claycomb Engineering Associates, 7-A-82 Proj. No. 1845.00I Page 10 n. Highland l'leadows Fif ing #2 topo showing Vail Village West Filing 3 roa<is in place, I" = IOO', 2'intervals. No date or record of who mapped. o. VaiI l.lest Ridge topo, l" = 5O', no date of flight or record of who mapped. p. Sheets , L,2, A7 of 7, Ilighlands l.leadows Filing #2 Preliminary PIan submittal by KKBNA. #l Preliminary Plan *2 Utirity Plan #7 Typical Cross Sections q. Sheets 2,3,4,5,6 & 11, of ll_, Highland Meadows Preliminary PIan submittal by KKBTIA *2 Prelirninary Plan *3 Grading and Drainage Plan #4 Utility Layout *5 Landscape Plan #6 Typical Cross Sections #I1 Preliminary Architecture by Harold Engstrom, AIA r. Specifications for Construction (not titled as such)Highland Meadows Filing #2, Muy, Lg1g, executed by Schmidt-Tiago Construction Company. s. Preliminary Subsoil and Geological Investigation,Vail Uest Filing No. 3, Chen and Associates, October 10, L972. t. Engineering Geology, Highland I'leadows, November 28,L977, by Charles S. Robinson and Associates, Inc.without figures (Figures subsequently recei-ved). u. Geotechnical site evaluation, Lot 22, Vail ViIlage l{est Filin9 I, Chen and Associates, July 3, l9gO. v. Daj-ly reports by l"toodward-C1yde Consultants of compaction tcsts and observation of base course placement and util j.ty trench comp.rction in Ilighland Meadows Filing 2 and Highland Meador^/s from September 16, 1980 to November 19, 1980. w. VaiI Village tlest, Filing #3, plat. x. Specifications for Construction (not titled as such )tlighl.and l'!eadows, l'layr I979, executed by Schmidt-Tiago Construction Company. y. Numerous it-erns of correspondenee relative subdivisions. n?"r. "". r84s.oor Page lI Material received from Leroy Tobler B-3-82. aa. Letter from Tobler commenting on draft report- letter ' included map of location of subdrains in Highland Meadows and !{ighland }leadows Filing 2. A copy of letter to Tirn carton on lO-31-79 was also incLuded. ab. Pages 2 and 3 of letter from Charles Robinson to Dave Elmore (no date as page I missing), relative' Matterhorn Village Subdivision Filing No.2. ac. .Xerox copies of J.arge Robinson Maps, Figures 2 & 3. ad. Summerlee letter, 3-24-'15, regarding Matterhorn Village Filing No. 2. ac. Chen and Associates daily reports, L9'79. Reports numbered 1 through BI, but with numerous numbers missing, such as #3 through 21. only numbers 22-27, 30,34-36, 38 & 4I are for road compaction. All other reports are for utility trenches. OnIy #38 has any reference to site conditions related to roads. af. Summerlee letter, 3-18-75, regarding Matterhorn Village Fiting No. 2. ag. Summerlee letter, 3-12-75, regarding !'tatterhorn Vill-age Filing #2. ah. Robinson letter, 3-19-75, regarding t{atterhorn Village Filing #2. ai. Richards Engineers letter , 4-4-75, regarding ltatterhorn Village Filing *2. aj. Chen and Assoej-ates Preliminary Engineering Geology and Subsoil. Investigation, Matterhorn ViIlage, July 13, r979 . ak. Water and l"lineral Consultants, f nc . , Environmental Geology of the Matterhorn Village Subdivision, Filing No.2, ll-19-73 aj. Chen letter, 7-24-79, rcAarding Vermont Road location near Station 20+OO. ak. Chen lett-er, 7-3-79, regarding waterline compaction, Highland Meadows af. Chen letter, 6-5-79, regarding Vermont Roacl fill across Vermont Criek in Highland Meadows. Proj. No. 1845.00I Page L2 am. KKBNA letter, lO-31-79 to Tirn carton regarding springs near Lot 24, Highland Meadows Filing #2. an. Summerlee report, Preliminary Soil and Foundation Investigation, Matterhorn Village Subdivision, F'iling *2, .November 15, I973. ' ao. Summerlee, Supplemental Subsurface In.zestigation and Slope Stability Analysj-s, Matterhorn Village Subdivision, Filing No. 2, September 24, I974. ap. ParL 2, Physical Site Characteristics, Soils, Geology and Vegetation. tioted in Tobler letter of 7-3-82 as being "Thompson's report included in VaiI Ridge Prelininary Plat submittal." aq. Thompson letter, L2-16-73 to Peak One Company regarding Vail West Ridge. ar. Wright Mcl,aughlin handwritten memo to Tom Everett,IO-2-80, related to utility trench compaction. as. Photographs supplied by Lerolf Tobler. tlii:;'":';:"il:;"l3iil". at Lot 2s. 5-19-BO - Looking at slope failure in cut slope.lO-80 - Looking at repaired slope with rock toe ii:;3tt:"t"ror"uo roqkins at repaired srope. Seguoia Circle and Tahoe Drive interseetion 5-19-80 - Looking at slope failure. A1pine Road from Vermont Road 9-10-BI - Looking southwesterly along Alpine. Other misccllaneous information received between 7-L4-82 and 8-7-82: at. .Individual soils reports on Lots 26-42, Highland Meadows, by Jerry Klug and Associates dated blovember 5. ]980 . au. Letter from L.R. Ladwig, Colorado Geological Survey,regarding Hj.ghland I'teadows, dated I'13-78. Proj. No. 1845.OOr Page 13 av. Robinson letter regarding Highland Meadows dated L2-L-77 . aw. Chen letter regarding cut slope failure, Highland Meadows FiIing #2, 9-L4-79, (Alpine Drive switchback). ax. Chen lettcr regarding cut slope failure adjacent to Highland Meadows Filing *2, 6-4-80 (Lot 22, VaiI Vil J.age llest Filing iI ) . ay. Ordinance #16, series LgF;z, Tov/n of Vail . I az. Denton Associates, Inc. letter regardi.ng Highland Park, dated 4-24-AL ba. Memorandum to Planning and Environmental Commission from Department of Community Devclopment/Peter Patten regarding Highland Park dated 5-f4-81. bb. Prints of Highland Park drawings, sheets L-24 by Denton Associates, dated 4-27-Al . bc. Lincoln DeVore letter report, r:egarding Subdivision Investigation at tandsLide, Vail Village (West). Lot 22, Filing l, 7-30-82. bd. CTl/Thompson, Inc. Ietter to KKBNA dated 12-2-?7 regardi-ng Highland Meadows. be. Subdivision fmprovement Agreement, Highland Meadows,dated LI-23-7A. bf. Subdivision Improvements Agreement, Highland Meadovrs Filing No. 2, dated IL-22-78. bg. Protective Covenants, Highland Meadows, vrith Supplemental Planned Development Regulations. The Robert t{. Thompson, Inc. Preliminary Geotechnical Investigation, Vail ltest Ridge Property dated .July ll, 1973 , reviewed July 24, 1973, liras received from Leroy Tobler at the August 13, 1982 review meeting. o Proj. No. 1845.OOI Page 1q B. BACKGROUND OF STUDY AREA The preliminary plan for the Highrand l4e.:dows subdivision was prepared in November of lgzz and revised in January of l97B for - submitta.l. to the Eagle county commissioners. t?re ?inal prat wcrs recordcd in Eagl.e county in June of 1979. The construction plans for the project were prepared in l97B by KKBNA. The only specifically noted date on any of the prans is .rune 3o, rgzg. A soll-s report is referred. to by R.w. Thompson and Associat-es. The Engineering Georogy Report was by charlei s. Robinson and J\ssociates. original reports refer to the development ars vail Ri,dge. construction of the roads was observed and testing provided by chen and Associates in 1979. _Additional compaction teit3-ng was piovided by lrtoodward-clyde in 198o.. The proieci was ultimat,riy accepted by the Town of Vair since it had-bein annexed subsequint to the plat'ting.in-EagJ-e.county. The actual acceptance is aatea llovember 19, 1981 forlowing a lengthy clrecklist and corrective action'by the contractor, Schrnidtlti-ago. t,ots 26 through 42 have s-ubsequentry b<:en repratted as Highrana parx through th6 Town of Vail. . The Highland.r{eadows riling #2 subdivision is a reprat of Vail - Village l^lest Filing t3, together with a portion-of the proposed -' Matterhorn Vilrage Firing No. 2. The vair vitrage l,lest Fiiing #3 area tvas platted in May of Lg73. The roads.ppuir to have been 'rough cut prioi to the time of pratting r"'hich *u= a common practice l-".!h9.9ar1y vail Virlage wesr Sunaiviiions. The soils report for vail virrage "rest riring *3 was prepared by chen and Associates. loils and geology reports for thl portior, 6f the propose<1 'Matterhorn Village Firing #2 which became a part of Highland Meadows *2 were prepared by Water and Minerai Consultants, Thomas E' summonree and charles s. Robinson. The prerirninary pran for the resubdivision of Vair Virrage west inro Hig;1ana-ueaaows Filing #2 was submitr-ed to the county rvith a date of June 30, 1g7B by KKBNA.The soils report for the replat was by chen and Associates. The final prans for the project^by KKBNA are also <lated June 30, rgla.Tlfe as-buirt <rrawing! ror the project are aui."J-o."ember 1979 and January 1980. The ioad constricrion and "iiiiiy-trench backfirr was tested by Chen and Associates in 1979. The base course pracemcnt on the road was observe<1 and testeJ: by-vlooaward-clyde in .scptcmber throuqh November of r9go. The pr"j".i. was accepted by the Toun of vaii, having been annexed to the To*n since the tirne of p-latting in Eagle counti. the approval retter is dated November - 18, 19lJl, foll6wing a Iengr-hy ctrecXtist ancl corrective action by the contractor, schmidt_Ti.ql. . .YliI Villagc tJest, Filing No in 1963. Very few records exisr.c:srqn, as the project pre-dates rcqur raments in Eagte County. !,.was recorded in Eag1e County of the subdivision pl.rnning and any extensive subdivision Proj . No. 1U45. OOr Page 15 Vail village lr'est, Filing No. 2, was recorded in Eagle County in I965 and also predated extensive subdivision requirements by 'Eagle County. Lots 29 through 40 were replatted in 1968. Continual problems of slope slumpi.ng and sliding, together with localized areas of road settlmenet have occurrcd in the second filing of ltig)rland Meadows during the construction period and since construction was completed. The largest problem in the region surfaced on the Bitetto lot, which is Lot 22 of vail virlage west Filing #1, where a slide extends f rom I\1r. Bit-etto's lot onto Lot 15 of Highland Meadows Filing #2 and into the right-of-wny and paved surface of AlPine Drive ' Little evj.dence of cut or fill slope slurnping is evidenL in the Highland Meadows Subdivision itself. The construction drawings for Highland Meadows indicate that an extensive subsurface drainage system \rr'as to be constructed including both separate t-rench drains and the installation of subdrains in al-l seh/er trenches. fhe as-built drawings for the project do not indicate the actual extent of these subdrains, nor do there appear to be easements for these subdrains when they are located outside of sanitary se\rer easements or the road right-of-way. fnformation strpplied by Mr. Leroy Tobler indicates that several of the scparate subdrains (not part of a sewer line) shown on the construction plans were not installed. The largest slope faiture in the study area occurred on LoL 22,Vail Vil]age West- Filing #I. This slide, first documented in 1980, moved with devastating swiftness on March B, L982, knocking a partially compJ-eted house from its foundation. The approximate outline of the slide area is indicated on Fiqure I. Construction cut slopes al.ong roads in Vail Village West Filing No. I have been left in a near vertical configuration. Evidence of small slumps in these slopes is visible. . The -m.r jority of Vail Village VJest Filing -+2 is on the f lat arcas adlacent to Gore Creek and has shown little sign of recent slope failures although some structures have cut into marginally stable slopes. The condition of the asphalt on core Creek Drive may be ,considered as a total failure of a road surface. Proj. Page III. PREVIOUS SOILS AND GEOLOGICAL REPORTS Numerous reports have previously been prepared dealing with the subject subdivisions including the following: ,... Preliminary Subsurface and Geological Investigation, VaiI (Village) Viest Filing #3, Chen and Associates, October lO, r9"12. PreLiminary ceotechnical fnvestigation Vail West Ridge property, R.l'1. Thompson, Inc. 1973. .... Environmental Geology of the Matterhorn ViIIage Subdivision, Filing No, 2, Water and l4ineral ionsultants, f nc . , November l-9, I973 . .... Prelirninary Soil and Foundation Investigation, Matterhorn Village Subdj.vision Filing No. 2, Thomas E. Summerlee,Nov. 15, I973, .... Supplemental Subsurface Investigation and Slope Stability Analysis, Matterhorn Village Subdivision. Filing No. 2,Oct. 24, 1974. .... Engineering Geology, Highland Meadorvs, Charles S. Robinson and Associates, Inc. November 28, .197j. .. Prelirninary Engineering ceology and Sub-soil . Investigation, Highland Meadows Subdivision, Filing #2, . Chen and Assocj-ates, .Iune 30, l_978. ' several reports have also been prepared rerative the landside of Lot 22 of VaiI Village trlest Filing *t as follows: Geotechnical- Site Evaluation, Lot 22, Vail Village tfest _ Filing #1, Chen and Associates, July 3, 1978. ... Letter report, Bitetto propcrty Terra Task, I'larch 5, LgA2. .... Letter report, Doug Bit-etto property, Woodward-Clyde Consultants, March l8th, 1992. .... Subsurface Investigation at L,andside, Vail Village West,LoL 22, Filing #1, Lincoln DeVore, 7-3,0-82. - copies of some of the daily report forms by chen an<1 Assoeiates for compaction testing during igZg-have been supplied. However,ntlmerous reports are missing. copies of dai.ly i"port forms and the I:.:ylt".of compacrion resrs performed by l,foodwara-CfyAe Consultant!otlrrn9 the construction phase through September, october: and Novc'mbcr of l9B0 werre .rlio supplied No. 1C l845.OOr Although the individual reports vary in the specific recommendations, ;ii reports dia)'ing wiin tne overall subdivision areasnnakesimi}arstat^ementsrelat-ivetheimportanccofsurface ;;;-;";;;rface drainage as noted in the forlowing excerpts: Proj. No Page L t "Soils have the tendency to slump when r"i"iut"a- This nece=sitates good surface and subsurface drainage throughout the Property' "The natural soils, unconsolidated slope wash' when saturated tend to slump and move a"*"ti"pu. This slumping should stop when these saturatld areas are drained"' "It is recommended that all cuts be kept to a minimum depth, on tlte order of 1O to 15 feet and no "t""pur ttran I I/2zL' Adequate provision stroura Le made for surface drainage through road embankrnents . " "Cut slopes should be stable at 1:l at 20 feet height over most of the area where groundwater conditions are minimal .'' "Improvement of surface and subsurface drainage wili improve the slope stability of much of the proposed develoPment. " Whenever ground water is encountered in a cut' culverts or pervious blankets should be used to control infiltration into fill and to Prevent. "f r.tf f ittg of the cut. Buttressing should be consideie,l because of slope stability problems"' "Previous blankets may be needcd beneath other fitts on t-he Property if adverse groundwater conditions are .?t"ou-.te"ted dur ing construction ' " "If seepage is encount'ered in cuts' the risk of sJ-ope inslabil ity is increased ' we do not' anticipate that leepage will be encountered' tror.u.i, it if is, ltability investigations should be conriucted to determine if the seeP<-lg'i ,ilt oarr"rsel-y af f ect the cut ' Good surface Jiuin"g" strould. be provided for aII cuts'" "Possibl,e Iining of drainage. ditches with impcrvior:s membrances such as asphal't or concrete to Prevent areas where accumulated surface water can Percolate dowll into the ""U""tf""e soil st-rata' The stability of 1845.001 chen , L972, Page I Page 5 a Page 6 Robinson, L977 Page. I Page 9 bage Io chen, 1978 Poge 7 SurF"T(-rIee,1973 Paqc u Proj. No Page 16 r845.001 colluvial type slopes can be drastically affected by induction of subsurface waLer or ground water into areas of potential slope failure planes.. It is believed that suhsurface drainage systems will probably be required around all structures located in colluvial soil areas. " The various reports relative the Bitetto lot also clearry indicate the existence of a spring surfacing within the slicle area. ltri- s serves as a graphic ilrustration of the accuracy of the s,tatements concerning subsurface dra.inage or seepage incluaed in the various subdivision reDorts. _ ft may be well to note that alt of the reports for the subdivision soils and geology that were reviewed were conclucted in the fall of the year. Therefore, the minimum subsurfabe water conditions were encountered during the drilling and field observation. Most reports make no specific projections of the probable condi-tions to be expected during the spring and. earry surnmer months when the soirs are subject to extensive surface- and subsurface water. The 1974 sumrnerlee report does include the following caution: Surmnerlee , I9'l 4 Page 3 "None of the test pits encountered firm bedrock formation, although some large boul_ders were present within the soii profile. Al_so, none of the test pits . encountered the ground water table. Ilowever, the test pits were excavated during t-he clry surrmer months of the year and perched ground water tables or isolated ground water scepage springs could clevelop in many locations during the spiing thaw and heavy run-of f period. ,, rn addition to cautions about ground water, alr the reports are consistent in their cautions about building designs, rimiting cut and fill areas, and other gener.rl constraints. The clegree oi restraint varies from repoit to report, but the b.esic theme remains the same. That is, the ilighland Mea,lows ancl Hightand l,le.rdows *2 subdivisions are rocated on potenti.arl-y unstabri to metastabr-e soils, r.vith local sma1l to llrge areas of unstable soils intermi xed . Thc appc'ndi,x of this report incrucres the comprete preliminary Y.Ti:-on Geo_logic Hazards rnvestigarion and sub;ivision An.rrysi's cornPl eted bv Lincoln DeVore as a part of this project for the Town of . V'r i I ' Tire Lincorn DeVore report dear-s with th6 speci f ics of .::l+t_and.geology, drawing o. oII the previous reporrs available as wcr I as f ierd investi"g.rtions and test borings by Lincotn DeVore . Proj. No Page l9 IV. EXISTING SUBST'RFACE DRAINAGE CONDITIONS 1845 . OOI considerable evidence of subsurface flow exists throughout the study area i-n the form of springs, secps, or moist ground areas.Previous reports have mapped some of these spots, but were hampered by the fact that the studies rrere done cluring the dry time of the year. Lincoln Devore's Prerirninary subsurface Drainage Map present a compiration of arr previously mapped springs and seeps as well as springs and seeps currently visibLe or: indicated by vegetation or other indicators. An extensive subsurface drainage sysr.am was indicated on the preliminary plan and the construction prans for Highland Meadows.'Ihe system consisted of underdrains beneath a1l sanitary sewers and severar cross lot interceptors in areas of known high giound water. ?he locations of these proposed interceptor drains are shown on Claycomb Engineering Figure I. Leroy Tobler has supplied i.nformation on the rocation of drains actual-ly instalred. tle informed us that all the subdrains beneath the sanitary sewers were installed, but that only a small amount of separate sub drainage system has been constructed. The locations of the sub-drains as defined by Mr. Tobler are also shown on Figure l. Mr. Tobrer stated that the subdrain instarled in Lots 3, 4, 4s of Highland Meadows is about 3 I/2 feet deep. This may be contracted with the recommendation by Robert rhompson 1n his letter of December 16, L973 that the drain be ',about 15, deep.,, - The onry subdrains called for on t-he preliminary plan of Filing 2 were to be along the souih rine of Lots 7 & B. r'1r. Tobrer,s information indicates that these rines lvere not- instalrcd.The rack of a planned sub<rrain system in the second firing may be due to ttre statement in the lgz8 chen report that "we do not - -anticipate that seepage will be encoun+-ered..,' The current \conditions, however, evidence extensive areas of seepage or .subsur f ace f Low. The fact that the field work by chen and Associates was done in the fall of the year may explain the conclusion that litt1e subsurf'rce flow exists. obiervations of the current condi.tions clearly indicate that the spring of t-he year condj.tions are considerably different than thoie anticiirated by the soils rcport. ,-__ Eu"l of.thc previous soils reports inclucle descriptions of the t-yp(-'s of soi Is encountered and the . geology of .the .lrea . I'lr e Lincoln DeVore report in the appendix reviews details of soil types, geology and specific hazarO designations. . Tl. rather complex gebtogy of the area may be summarized in sitnl;Iicr terms as folIows. Tlrc area generally consists of a rel.rtivcly thicl< mantle of slope w.1sh, ancicnt_ landsliclc or coIl.uviaI material some 20, to lOO, in depth ovcrlaying the sattclstotrc bedrock. The soil. mantle gcneral ).y eonsist-s of a sandy, Proi. No. r845.00f Pag6 20 silty clay with intermixed gravels to boulder size rock fragments' Surface moisture infiltratei into the soil mantle and migrates giaau.-,f fy down the slopes' The north facing.sJ'opes accumulate very i;;g; sn3w packs during the v"inter months which are released gradually through spriig snowmelt' A significant portion of.this water soaks into thl soil l.yu. and migrates down the mountain side.Asaresult,thesurficia}soilsarecornmonlysaturated throughout the spring and early sunrmer months' Since the soils have a Iimited r?""ifii""ibifiti/, a considerable period of time is necessary for underground flow to rnove from the upper mountain areas to the Iocation of Gore Creek' Therefore' the period of saturation extends well beyond the snowmelt season. The occurrence oi spri.ngs simpry indicate-s a location whsre a relatively pervious strata of soil surfaces The condition discussed in the previous paragraph is totally natural to the arei and will continue to occur until steps are taken to counteract the natural phenomena. T'he inslall'ation of subdrains in the Highland Meadows subdivision have apparently ..i".pii"ited this .ia in some locations. Si-rnilar measures should lurt.i." in Highland Meadows Fiting *2 :-t the continual slumping and sliding of cut slopes and filt slopes is to be reduced. As ,.rot"a in tie soils reports. so long as the soils are subject to saturation, slumPing ind sliding may be exPected to continue to occur The condi.tions previously identified in the Highland.Meadows subdivisions extend on into !h. upper Portions of Vail Village west, Filing No. L 6,2, along Alpine Drive and.sierra Trail. The slope failuie on Lot 22, Yail village west Filing #I' clearly 'ilLustrates the potential problem. Available geologic information indicates that a similar event could occur on other lots in uPper vail ViIIage West Filing No. 1& 2 if a steep cut is oPened' v. proj. No. l845.O0l Pale 2I EXISTING SURFACE DRAINAGE CONDITTONS The historic natural drainage pattern for the study area c.on.sisted of diffuse overland flow v/ith rninimum concentration of drainage basins throughout the majority of the site. This drainage - pattern is crearly indicated by inspection of topographic maps.Only one larger drainage basin through llighland Meadows, traversing Tracts A and B, has a well defined valrey section with concentrated , f1ow. Dense vegetation consisting of spiuce and aspen arong with dense uncergrowth serve to retard the surface flow,- allowing a signifi,cant amount of infiltration and controlling erosion. ' construction of the road system in the Highrand Meadows subdivisions has served to intercept the diffuse overrand flow and :o.nvey it to specific curvert locations as illustrated on Figure 3. Areas that hjstorically, based on topographic map interpretation, had just a few acres or lriuuiary driinage basin,now have rarge tributary basins. specific examples are the ,.intersection of Alpine Drive and Tahoe Drive in Firing #2 where 24 acres are presently tributary to a point that historically i.rad a drainage basin of three or four acres. The culvert bene;rih vermont Road at Lot r in Highland Meadows F.iring #2 has a currenr drainage basin of 80 acres whire the hi-storic balin was approximately 5 - - acres . No specific drainage facilities were constructed as a part of 'the Vail Village West !.iling #3 plat. A 1,,=IO0' , 2, contour interval map showing the rough cut roads prior to construction of Highland Meadows #2 does not show any roabside ciitches arong most . of the rough cut roads. The rough cut roads alrowed much of the surface frow to cross over the roads, therefore having little affect on the naturar drainage pattern. The preliminJry plat- for Highland Meadows tsi1in9 #2 indicated roiidsicle ditches clp-turing flows along the road system and cul,verts discharging thoie froivs into Vail Virrage l{est Irili-ng #1 and 2. The finar construction plbns and actual constructed facirit ies eliminated t-wo of the curverts shown.on the preliminary plan, thereby concentrating Bo acres of basin to the culvert bcneath Vermont Road at Lot r. rt appears that this may have been done since no easements or adequate facilities existed through vail virrage r{esr riiing #r and 2 ro accomnodate flows from the upstream <rreas. The resur.t of the drainage facilities construcied in Highland t.teacrows Firing #2 has 'been to concentrate the f r.ows in areas noi previousry subject to such quantities. surface drainage facirities such as curverts are ,nomi.nally adequate to carry tte it_lO year flow. Proj. No. 1845.001 page Zz The affecf- of concentrating runoff into areas differing from the historic routes has a substantial impact on the subsurface flows. Areas which $rere prcviously subject to a relatively small drainage basin to replenish underground flows experience continual vretting, Springs may be expectcd to appear where they were not previously evident. Previously stable areas may become unstabledue to additional moisture. The concentration of flow to the intersection of Alpine Drive and Tahoe Drive may very well be a contrj,buting factor to the Bitetto lot landside. Road subgrades are continuously saturated when roadside drainage ditches traverse Iong sections of hills j.de without culverts to remove the surface f_Iows. fhis may contt:ibute to fill slope instability. The Highland }leadows Filing li2 surface drainage system has reduced the surface drainage problems through Vail Village West Filings *I & 2 by reducing the offsite tributary basins. The historic natural drainage that entered the Vail Vi-I1age West filings alI along their south boundaries has been intercepted and conveyed to the single culvert under Vgrmont Road at Lot I. Only scattered sections of roadside ditch exist through the VaiI Village Vlest subdivisions and few culverts exist beneath driveways. Two culverts, as illustrated on Figure 3, carry flow accumulated in the ditches beneath core Creek Drive. Most areas flow dj-rectl1' across Gore Creek Drive or Alpine Drive to Gore Creek. Localized flooding may result when flow crossing a street at a random point encounters a house. Adequate surface drainage for both Vail Village West Filings can be provided if the roadside ditch system is improved and culverts installed at driveways. The quantities of flow are small enough'that improved ditches, paved swales along the sides of the r6ads or curb and guttered sections r.vould also be adequate to carry flows to the culverts beneath Gore Creek Drive. Consideration has been gj-ven to bringing the flow from the intersection of Alplne Drive and Tahoe Drive through VaiI Village Wust Filing No. 1. This'alternative has been ruled out due to lack of easements, topographic constraints, and the geologic hazard of the upper portion of Filipg No. I. A culvert should be ext-ended along the lot line between Lots 47 and 48 of the 2nd Filing to intercept flow fron the culvert beneath Alpine Drive at Vermont Road. Flows for the lO year (1OB probability) ancl the lOO year (ft probability) return period sLorm events have been calculated by Clayconrb Engineering Associates, Inc. and are shown on Figure 3.The flows were carcul.ated utirizing the soil .conservation service ncthod for rainfall derived events and snowmelt flows were calcttlnted based on gauge rccord analysis in the high mountain Proj . No. 1845 . OOI Page 23 area of Colorado and the procedures presented in the U.S.Geological survey pubrication Magnitude ancl prequency of Froods in .the united states, Part 9, colorado River Basin. A lable on Figure I shows the calculated capacity of the existing curverts and the calculated I0 year and IOO year flows. The surface runoff contror facilities recommended by craycomb Engineering Associates are ilrustrated on Fi.gure J.. rmprovements to minimize the concentration of frows and return frows as nearly as possible to historic drainage routes are normarJ-y recomrnended'by our st-af f . Ho'dever, extensive acquisition of easements and construction of drainage facilities through Vail village west I and -2 would be required since none now exist. Due to these limitations, an alternate solution consisting of a combination gtorm sewer/underdrain from the vicinity of ite Alpine Drive .rnd Tahoe Drive intersection to the present culvert ar- Lot r on Vermont Road is recommended. - By raying the storm drain in a graver medium it will serve the dual purp6=. of a storm sewer and an underdrain along with a subdrain pipe. T'he surface drainage facitities through ltighland Meadows are generally satisfaciory. Less extensive concentration of frows has occured in IIighland Meadows than in the 2nd filing. A well defined naturar channel serves as an outret for rnuch of the area. . This natural channel traverses the core of the streamside development. The finar details of grading around the st-reamside project will be very important to prevent possible damage from this rarge drainagl basi-n. fhe intet to the curvert in Traet c beneath vermont Road must be exposed as it is novr covered with trash and fill rnateri,al that appears to have been removed from the construction sites.This trasl 1"d spoils shourd be cleanerr out of the road fj_rr area and the fiJ.l rcvegetated. A satisfactory drainage pat-h and facilitjes, together with app:opriate easements, is needed from the west end of Vermont Road to Gore creek. Runoff from the r,rest end of Vermont Road flows into Lhe Elr.iot,t Ranch suuJivis:_on and has previoursy done damage in the area. The rocation of Erl.iott Ranch subdivision was shovrn as Nationar. Forest on the prerimin.rry plat and no provisions for offsite drainage were pro,rid"d. Generar 3:"tJ?t drainage improvements should be made in the area of rots 12, 13, L5 and 16. Proj. ltro. I845.OOr P.rge 24 VI SLOPE STABILITY The Lincoln DeVore report contained in the appendix deals extensivcly with slope stability in the study area. The Preliminary Geologic Map, Preliminary Subsurface Drain.tge Map and Preliminary ceologic Hazards Map indicate the combined results of the studies by previous soils and geological engineers and the independent observations by Lincoln Devore. By super irnposing these maps onto Claycomb Engineering's Figure 1, Existing and Recomrnended Facilities, the extent of impact by each geologic feature may be observed on the building envelope areas.and on eixisting structures. (tne existing structures shown are only those illustrated on available topographic maps and do not represent all e-xi st ing structures. ) The primary conclusions of the Lincoln DeVore study and the work done by Claycomb Engineering Assoc j_ates may be sumrnarized as follow: f) The majority of the Highland Meadows Subdivisions and a substantial portion of the Vail Village l.test subdivision are Jocated on potentially unstable to meta- stable soils 2l 3) Most areas are subject to slope instability if excess subsurface fLow exists. Lots 10-14,22-28,38, 39,40,44,45,4'1 ,48 and 49 in Vail Vi11a9e West Filing No. 1 and lots 42-50 in Vail Village West Filing tlo. 2 are all in an area designated by Lincoln Devore as metastable where extreme caution should be exercis-d in design of buildings. The provj-sions of Ordinance 16, Series of l9B2 should continue to apply to these lots, with very thorough design of mitigation meas ul:e s reguirecl . Cut, .slopes into the steep hillside at the b.rck of Lots 41 through 5O in Vail ViIIage t{esr Filing Lro. 2 and Lots 46-48 in Filing flo. I should be avoided or even prohibited. Existing cut slopes, such as tlrose on Lots 4I , 42 and 43, Vail Village llcst *2, should be carefully monitored for signs of failurc. PiJ-l slope movement is evidenL along much of AJ_pine Drive,Tahoe Drive and Sequoia Drj.ve in the form of longitudial cracks appearing in pavement surfaces less than 2 years old. The area wide subdrainage systeJn recommended may 4) s) Proj Page r845. OOI reduce fut-ure movement to acceptable limits, except at the Alpine Drive Switchback. Removal and recompaction of the fiLl in the Switchbaek area is recommended along vrith subsurface drainage measures. I'he magnitude of movement of other fill slopes should be monitored by setting reference points in the asphalt and surveying their location at int ervals . Cut slope faiLures in the form of slumps or stides are evident at thc Alpine Drive Sk/itchback, the Sequoia Drive cul-de-sac, the Tahoe Drive/Sequoia Drive intersection and on Lot 22, Vail Village l{est Filing No. I. Excess ground water is evident in each failure area. Following the installation of arca wide subdrainage facilities, these areas should be repaired and monj_tored for evidence of movement. If movement persists, then installation of retaining rqalls is suggested. Treatment of Lot 22, yaiJ- Village West Fiting No. I is treated by a separate report. Significant portions of Highland Meadows, Highland Meadows #2 and Hyland Park are with areas defined by Lincoln DeVore as possible solifluction zones which are a form of soil creep. Only a portion of the area wide subdrainage called for on the construction plans has been instarled in this area. The existing installed system may not- be sufficient to arrest this area wide movement- to acceptable limits The degrees of stability of aII of the study area is discussed in the Lincoln DeVore Reporr. The stability condition of virtually all slopes may be summarized as follows: existing slopes and moderate height cut areas at slopes 1ess than L I/2:1 and moderate height fiII areas at slopes less than I I/Z:l will remain generally stable if excess subsurface flow does not exist. This stat-ement is based on the assumption of proper initial construction. Excess subsurface flow mav render any of the above mentioned slopes unstable. The existing near vertical cut slopes on Alpine Drive and Sierra Trail in VaiI Village tvesr Filing I ihoulrl be considered unstable. corrective action shoul-d be taken consisting of cutting the slopes back at 2zI and/ or instarring retaining walls. itre slopes along Alpine Drive are of particular concern,, as. they exist in an aiea mapped as metastable by Linco]_n DeVore. NO 6) 7) 8) e) ro) o Proj Page . No. 2e r845.00t 1r) L2. 13 A system of underdrains throughout Highland Meadows Filing #2 and Vail Village lJest Filing I is recommended, along with completing the underdrain system proposed for Highland Meadows and adding some additional drains. Not only wj-11 these drains serve t_o intercept subsurface flow throughout the area, but they will serve as the outlet for individual building subdrains. It should be a requirement that all building subdrains be connected to t-he centra subdrain system and that all roof and site drainaqe systems be connected to the area wide surface clrainage system. Otherwise, water collected by an indivicluat building system will be reLeased on the ground surface to re-enter the ground water cycle. The recommended sytem is illustrated on Claycomb Engineering Associ_ates, Figure l,Exist-ing and . Recommended Facilities. A surface drainage system that removes surface runoff frorr.roadside ditches to minimize saturation of road fi1ls i,.,recommended. fhis system will both serve as a portion of the subdrain system and the surface runoff systam. The recommended facilities are illustrated on Cliycomb Engineering Associates Fi.gure l, Existing and Recommended Facilities Some localize<l slumping and raveling of slopes should still be expected even after installation of the subdrain system recommended in this report. This will occur during the actual spring snowmelt perj.od and during rainstorms.The only adverse effect expected from these occurrances would be accumulation of soil in the ditches. If such accumulations are objectionable (that is, of such quanity that a normal good ditch cleaning program does not suffice) then small. retaining walls such as shown in Figure 5 may be installed. Thr:se walls would actually be to catch debris and sloughing from the sropes, rather than t-rue rcta ining wa I I s . ?t uLAYuoM ErNcI;r1il,3*";y"ru" rNG. . GLEI{WOOD SPRINGS. COLORADOEI6OI (303) e45€676 cxe*xo.FtauRFl] or crrcur^teo "v3,Lil- one 7-14 - 3I CHECTCD 3V sc^Lc l't=20t HoRlZ. .l,,t /O, VERT. I a / / -,./ --- q a t{ .? c.rl \. - ..rr Croro|ll^rrr OtaS xl57NA *trNoe TIE BACKS \ FOR RAILR4,O CqT SIOPE. THAT I5 A,PEilENCING SURFICIAL SLUMP'N6 ROAO TIE M'NOR RETA'N'N6 SLOUEHINC 'NTO MAE HErcHT 2' $,ALL TO D'TCH t 9e" F.oex pltL FILTER FABRIC wttH ON TOP. TYPICAL DETAIL . RAILROAD TIE MINOR RETAINING WALt TO INTERCEPT SLOUGHING cAurl0N:- THrs rs Nor A RETATNTNG wALL ro HoLD THE sLopE, rr .rs A STRUCTURE TO INTERCEPT SURFICIAL SLOUGHING BEFORE IT ENTERS ROADSIDE DITCH. FIGURE 7-t4-82 29