HomeMy WebLinkAboutGLEN LYON GENERAL LEGALI
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Appenorx
ENVIRONI'IENTAL III1PACT REPORT
GLEN LYON
VAIL, COLORADO
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PAR"T IV APTjINDiCES,
This matenial is i:nesented Lo stlppor^l f indings and
concluslons conta irred in the Envi r-onmetrLal Irnpact Repont
I'on Glen L-yon. It pnovides rrrone baclcgrorlnd infLrr'fi-lation
on subject.s summal^izecl in tire mairr nepoi't, dated
Septemben, 1977.
Appendix A Geologic SuPPlement
Appendi;< B Snow Avalanche Hazand Supplernent
Appendi.x C Ain C-lualit5z Supplement
Appentlix D Wat.er Q.uaiilry Supplernent
Appendix E -I'ral'l.ic Count Data
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APF'ENDIX A
GEOLOGIC SUPf]LEMI-NT
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Geologic Su1;5:1ement, A pp€:r(li){
REGIONAI_ GEOLOGY AND Gtr.Ot..OGIC HISTOJIY
The intent of l-lris supplemcnt is to cle::cnibe tlre negi..irral geolo!.y
and lrniel'ly neview tire geologic histony oi= Lhe Gor.e Crec:l< Valli,..7,
This additional infonrnatlon may pr^cvide a rnone con-rljlete urri,irri-st;rnclii,.,j 'of the geologic setting ol' lhe pnopos:ed dcvoloprnent, Gien l_yon, whi.clt ir
discussed in the rnain body of the rcpor^t, I'Envinonr nerri:.rl iml:acl [:(clror.i:.,
Glen Lyon, Vilil, Colonadott. As a beqirrning to Lhe iilscussion, a
nevie\./ of the Genenal sLi'a.tignaphic; secli.on, Figr rne 1 , rnigirt lrr: lre lp'-
ful. l-lris chant will. senvc as a r-efer^ence i'on itre cliscussron.
Tiris stnatignaphic section is an annangernent of geologic nocl< r-rnits
inlo chnonologric sequcnce, oiclen nocks on the bobtonr and younqer- or)(:-rl
ori top. Pnecambnian, Paieozoic, Mesozoic and Cenc:oic Ena.s are
ti-r'r pnincipai time subciivisions, and each is then funtiien subdirzide',c
irrt.i> Peniods. A geologic time scale is ne-pr ocjuced to Ll're le i.t of. ttte
ser:tion and shows; the nelatir.ze time irrvolvcd; note tirc exir.erne lerrgth
of the PaLeozoic fna (343 Miilion Yeans) \r',/hen compa.ned to th:: younllt:r.
Mesozoic (155 Millton Yeans) and the Ceno;:oic (7O Million year.s).
Sedimerrts of the Stnatignaphic Sectioi., vany greatly in depositionai
envinonment' , r'angi.ng 1=nom ancient continental floodpiains and desenls
to beaclres and rnanine sandbans ar-rd li.rnes'cor1e banks. l-he iirre gnapl-r
to the nigirt of the section depicts tl-re tnarrsitiorrs, with geologic time.,
fnom marine conciiLions to conti.rrenta_l and vi.se vensa. Genenaliy,
the chai'rges fnom donrinantly manlne conditiorrs to coniinental ,.arer'c !l-r.:
nesult o{' mounta in-bui Id ir, g episocles, e.g., Ancesthal trront Rangc:(late Pennsylvanian Peniod) and the lv4ocJenn Roc!-.ies (iate cne{-aceous Peniod). As we tnavei on oun jour.ney thnough geologic time, noLe
par^ticulanly Lhe thickness of the stnatigraplric units and Hrein sedi-
mentany chanacLen. Manine condition-s ane favonabie fcn Lhe accurnurla.i-ion
of gneat thicknesses of sedlment, wleeneas urnden continental cc-,nditions
enosion dominates and littie sedimenL is penmanenfl5z accurnulale:cJ .
Indeed, note the pnepondcnance of unconfot-mlties (ancient enosional
sttnfaces, shown as wavy lines be'orrreen stnaliqnaphic units) duning ti.mes
of pnedominanlly continenbal conditionc. Ginora the rlool6gic unil_s of
,|'Depositional Envinonment: sedimentany nocl<s ane composed on nock
fnagments of vanious sizes that have been consolidatecJ b-y depositional
pnocesses (wind' waten, ice, gnavity) in par.ticulan unique envinonnrents;
these depositionai envinonments in the gr-rologic past ane the same that
ane seell today; exampies ane: mor.lnti:in stnearrrs; sc1t1d dunes, qlacien,
manine beacl'r, mantne delta, bnacl<ish bay, estuany; cl'rar nacteni stics
seen in sedirnentany nocl<s, then, ane a dinect nesponse to its uniclue
depositional envinonment.
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Ma.oon F crmr.lLc.
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2CO-3CC'
250-500'
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o-125'
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i-r,eorrs ro.ke, siltrfone5,
co..loar!,.ai. - i1,r,J ...n(l!tones
t):r.k .r.1.i,1e .:l1rl!, srl!!ronc
n :d l-rndsLone
Nh.rne sillstoff , slile
D.!.k ma.ine 5\ele
M3^f jr;rl m.rr ine sancstohe
lr1i rci.al mari4d siltrtone,
clayslone, s:1,,.1-,io^c t limeeia-ro
Non-ma.i^a s.lrrd!,tono
tlon-nla.ine 5illst(ino
l\ion- ma.16e s<rndslonc,
olonre.aae and sili.lsde
Pennsyl./anL1n
-310 Ni. Y,A.-
M i. !,i:j:trppir.n
Minlvnr Fonnrarion Ma.inc and mf,.YJi.3t m.arh\s
sarlCston.j, siltefcrle, con_
glomerale and iLrnestcne
Celd€n f:o.rr).itioi a-200,Dark r.a.inc sr6lc llmesloie
Lcrdville L Lmestc^c o- 195'M.r.9 inal marine s*_rnd ahd
ClEfTee Fo.nr..rtion o-130,F:uvial s.lnclsto^cs and rnrrlinrt
nT arine doloriiile
Siluria,r IRODED
OrJovicind Harding San.l5ronc o-501 r,rercli to ma.ginrl ma.ino
570 M. Y.A. --
Pcc.lc5s Fo.'r.r!ion
S!r\r.,tch S.^dslone th in Gc.r.h :rJndlto^es dJT d
ri,.r<rinnl mdrine dolonrlle
Mcti'noq)hlc
'Mll llon5 of Ycnrs AC<J
FIG. 1
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the lower. Paleozoic Ena cutcr-op (a;:,;.,e;rn at -re s_t l^l.irce) in ane_as
west of the Gone cneel< Vallcy nean lvlinttrrn, the <Jis,,cussion o1= gcologic
histony begi.ns in the mlcjdle to lerte paleo:.zoic Ena i Pcnnsvivan iai-r
Feniod).
Duning tfre rrrictclLe e.nd lirte Palco.::rtc Er^a (s:.:e stniitie naphic se:ction)
the pneserrt l.ocaLion c-'f Vail w;lr; f lanked or-r tirr: east a|rd northeast by
the Ancestr..:l Fnont l:lange and orj ti-,e \,/i].si: norLflw(,,5i l-r52 the Eagl e
(on ,\4anoo,n) Basir-r. AL: tlris tirne, enoded rro.ienial f i'orn ihe highiands
rvas being cannicd to tl-re wcst [:52 sti^eams and dc.:posit:ecl a.t the basin
margin. -l-hi-s aircestnal highlancl exlendec_i froil lhc appnoxim;:Le posi-
tion of the Gor^e Range, on the rrves,;1, to tlte east: slope of thc pnesent
fnont nange.. AL the b;rsin mar'gin these clas,;ic seclim';n';s (sarrds-;tones,
silbstone..', conglomer aites; and clays) rnixed rryith limestones ancj evapo-
nitr.:s (954r:;urn) o1= the shal.low nrarine ba.sin. With tire passage of time,
col,iinued upli'it of the Ancestnal [:r"or;t Rang;<,: and i.nci eased enosion
pnociuced gr^eat r" edges o1' se<ii.rrrent c><tending i'nom tfrc highland irrto
the basi.n. Ccnoomitanlly, lhe marine seras of the basin receded
fnonr the region towarnci the nonLhwest. wiLh ilrc netneat of Hre seas,
vast aneas of the clastic rvedge and the corrLinuously enoding highiand
wene exposecl to atmr,:spher.ic oxideltiorr and tlr... fennous rninenals in
the claslic sedimentany werJge becarne oxicJizecl , pnocl,-t.ing ned and
ona;rr;e hues. The sccjiments thr.rs fonm,ed ane pnesentiy cla.ssified
the Minlunn Fonmation and the ovenlying Manoon Forrnation. These
two for-mations compni se tlre bednock of the pnesent Gor^e Cneek
Valley and undenlie tlre pr.oposed Glen Lyon clevelopmer-rt sile.
Continuing the histony of gerc,iogic events, clunirrg the eanly Mesozoic
Ena this anea conttnued as a bnoao' uplanci clranactenizecl by streams and
clesents. Unden these concJitions, enoded matenial di<J not accumuleite
in gneat lhicl<nesses as in the pnevious basi.n seLting, but menely
slrifted as a thin veneen fnom one loc.rle to anothen. In Lhe late
Mesozoic Ena (Cnetaceous Penio<J), seas once again netunned to the
negion. By tl-ris time the geogr-aplry o1= Llre negion had changed con-
siclenably. -Fhe Ancesti.al (Paleozoic) Fnont Range had been leveled
and inundated by a gneat Cr.etaceous seawa-y wlrich rn,as fonming in
centnal CoionacJo and wl-rich extendecl fnom nonthenn Wyoming thr^ough
New Mexico. To the west, in easler^n Utah and westenn Colonaclo,
a gJn,.:lt mourrtainous land mass was also fonrning and pr ovided enoded
matenial fon Llre cnetaceous basin. -T'tre thic!< undenlyinq paleozoic
manine and continental sediments (Mintunn ancl Manoon) and the thin
Mesozoic corrlinental seclimenls wene now covened by ricl< cnetaceous
rnanirre and r-I1anginal marine sediments. T()wa nd the end of the Meso-
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zoic Ena (late Crcta.ceous Penioci) thc rr.,;lr.i.r:r: {r..,.\^/,:iy r^etnc.rtccJ f no r-i-r the at'ea, fon tlre late stagcs of Lhe Cr^r,t;rceours \/!/i.! s a ti.me of l-nernen-
dou.s nrountain-brri lding activity. Dunirrgl t[ris; tin.rc the gneai Roct<y
Moti, ri.;iLrr t'spinet' was fot^nrr.lcl . A .gnc;,r{_ ccni:incnt.rl ;artrcl ma..:s flankecJ
tl-rer F*ocl<ies on borh the ea:;L ar^rci \ /esi- ilild pr.rsr-rr:i-j rnanine seas l.an
1=nom tl-iis region. l-he Cope fla_nqe v!/a:r cnt: of lj-:.. rnorlrtain masses
1'onmed duning ti.ris nrountt;in buildinq Lt\..(. j rl ancj ca,i tt.n()lli:.il l_;r,il;sequent geologic events in tlre Gone cr.eek Vallr:y. corri-i.rrr-,e d n-:i--.ur-r,air-r-.building duning tfre eanly cenozoic L-r^il r^csi-rl;.,.ci in c.rlensLvi: c.r.osi.orr wkr'ich ci\./entually si-ri1-;pecJ Cre,t.tceOus aln,J o'al-ict. ir4r::;czoi.c secJIr-;-ir:nt:; atrcJ utllmate).y exposecJ the undei^iylng up;- .. parleo::rtic s;ircliments (fvlintur n and Manoon Fonrnaticns),
The late Cenozoic; ti r.a (Qua.ter-r.:an..),. Pepiocl) is cl.ra5.acte,:r^i z_c,cl b.z
rnounte'i-in valley qi.rciar_tiorr ra,rhicl^r p r,.::,d 1rc iiqJ tire lapilgjcaJ).: we see today. Valley glacicr-s, oniginatino higrr in il-ic Gr;r'e Rangr, acivanced
a'.nd retneated malry tinres, .pnodri....i.ng at least llirc::: deposillonal e,,,ents,and deposited s1s1'1inal till along the rvaills an:.r ,.,a1icy floor. of Gone
Cneel< Valie5z.
The pnesent glaciatr:cl, on ,u, shapecJ, vai.1e5, pr.oiile ,was foi.mecJ at this time as glaciens adve.nced ciovr.,n re valle_.,.,. These glacier.s
scouned arrd Itplucl<eci'r nock fr,aqments,: iroi-n the vallr:y I'ioo; ancr walls, and cannied this matenial in thr.ee diffenent ;:-:i,:.6ss in i,",giacien3 |) at the base of tire glacier^, 2) at the ir.ont, on leading
edge of tlre glacier., and G) along the lalenal ed!r.i; of the giacien.
When the giacien netneated up-valley c.lur^inq war rrr.-climate cpisodc,s,tiris l66ser, fnagmental matenial lvas delrosited on the valley floon
and walls as glacial til1, on mone particulai^ly as monaines.
With the retunn of warnren clirrraLe and re final neL;^cat of re glaciens, stneams entening Gone Cneel< fr^om the glaciated valley wails, cannying tnerngnCous armounts of nraterial, cleposiL,: ;j this
sedimerrt as alluviunr" fans, for^ming on Ure vallcy f1oon. Otten times unstable, unconsolidatcd matenial in the.se fianking dnalnage
basins would begin to slide down the dnaLir-rzrges, inconponatinq n,cck,
mud and debris as it rnoved, and eventually spr-cad out oven flre fan
and deposit this debnis flow rrratenial . Toclay, steep glaciated valleys
ancl lange amounts of metastable (not fully stable - capable of down-
slope movement), unconsoiidated matenial on .re vailey walls, the
nesult of long peni.ods of exposune to wca renirrg anci qlaciatiorr,
have combined to pnoduce potential hazar-cl aneas rarhich inflrrence
man's acttvities in the Gone Vallev.
'Allr-rviurn: fnaqmeni-ed matenial cannicd by slneams (fiuvial pnocesses)
floon:;.and deposi Lcd on valley
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t SITF: GE o LoGY - !--,e9n?g:_!:leg.lt=
I l" l'e bcdnocl< geology of the site consisi:s ol' the fu'iiri! .rnri I:: o i^nra l-ioi'r
I (Pennsirlvanian ;rgo) and [s descnibeci a: I'c,llow:;:
A,lecliutrr l-o coi.rnse-gnai rred qnay ti) r-eclclislr irrcr.,'n sai-r.ir; L.rnc ,
congl.omen.itic sandston::, thirr becjs o{-' reCCi5-.-l,i brov,,t1 :riltslone
and -sandy anii silQv slrale elncl pr^or-r-:ir-:---itl p inl<isir.-gi.ary to gi..ry
limesr.one beds. (Robi.n:.,on, igTii)'r
Near" t.l-ie Gien Lyon site the b..,.;;^oci< s,L.r.at.a dip ai irl: t-c,rx i rrra l::1y 15 ci;:qr.ees
to the nonLfreast" The Minttrr^r'r Forn^itrl-iot1 v/as ci.positeli r'lr ,,.inE tire
eanly Lo late Perrnsylvania.ln Period (see Generali:ied 5 tnati <1n;rplt;:
Sectiotr) nlong lhe eas;t flanl< o{' the [:rgl.o (Ma.r'oori) Basi.n l'r^or-r r nrate; iai
enoded fnorrr the Ancestnal Fnorrt Ra,r^,ge, locatcci eirsl ol' t-l-,,.: sLte. Tirase
clastic sediments (cla.ys, sllts, edntj:; an:-i conglorrrcr^.j1t€s) ionme cj a sodi.-
mentary wcdge appnoximately 6, OOO l-ect thicl< tnrlr i c.:l-r iirteniirrgcnecl r.vil-h
manine liirrestones ancl evaporiles (gyr-rs;Ltm) as it thinnecl l_orv:ir^d Lhe
nor ihwest. The cion-rinant clay miirer..j.ls in the srl-lCstol-te-c, shales arrd
mL.rdstcres of Lhe Mi,riur.n a.r^e illlLe, nlixe.J-layer ciiry rrrrnenals arrd
chlor^ite (the highly exparrsi'"<: clay, rnor-iLn ioril..<.,;r ii - i:: absLirL on sfi.r.-c)
(Boggs, 1966).* The resi:;iar.r';c limest<-,ne uniLs; cif Lhe Mir:Lur^n t=on n"r
neat-l5u ventical cliffs l-ri.ghen on the vailey wall aborze tire site. Rut for.
the most pant the site is underlaln by nonnesisl-ant sharles, siltsone: :.j,
claystonlrs and sandslotles. The higl-r cnodabii.:Ly' ol' l-his bedr.ocl< arrd
subsequenL geologic events associated rvith giaiciatiorr have produced r,
mosaic oF unconsolidated rnatenial (sunl'lciai geologic deposits) whiclr
mantles Lhe valley walls. J lrls unconso li cjate cl rnatcnial , vvl^re n fcLlnd
on steep slopes , is subject to nrass-'rra'rsti ng (cnr,rvi Ly induced sl ipprr.gr:
on flow downslope), but nates r1-ray vany ccnsicjenably fnom veny slow
to naoid.
SITE GFCI-OGY - Sunficial Deposits
Overlying the MinLunn sandsLone, silts;tones, conglomenates ::nd lime-
stones is a complex mosaic o{- sunlFic:ial geologic r_rniLs (Robinson,
1976). This sunl'icieri mal-enial is pninranily unconso lidal-ed, Lrnstnal-il=ied
s"Geologlic Hazancls and Resounces in Eagle Counl-yrj by Chanles S.
Roblnson and Associates, lnc. (197O)
4ttPeti^ology of MitlLunn Fonm:rLion, Eas;l--Centnal Eagle CounLy, Colonadorl
by Sam Lioggs, Jr., Bulletin of the Amcrnlcan z\ssociatiorr oF petnolcrum
Gcologists, U.50 n.7 (1906), p. 1399.
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E collttvium" irnC othen :;,1ii i menl-.ri y pnoclucts of' mas-c-yy"rsting clcposited ' clLll^lng Llre: (f,-L.ralennany per.iod (late cenozcic Er-.a). [:on ct:i.,vc rriencc,the folk.rr,vinr; clcscript.iorrs of the sunficial geologic uniLs ane sepanated
into those losale6 on tlre steep slopes and r"hose loca t.e cl on modcnale
Lo gentie slopes (See Sunl.icial Gcotogy ,Vap).
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te ge*Q-lgrti*lln !l:t-l*
9!_.-,,i15E]^v_-_l]g1:f1iil,1:-"_-pct!p_1ex: a compl.:x of slope tailr.rne,s, such
a,s ciebni.s sllde t;, l-r rucif iovr.s, ctr:bni-s florn,s, landslides, et-c. ; the
sc)unce rna.tenial lrene is tire [:rr.:. r rnsylvanlarr Mintur-ir Fonnra:.i.i.on arrcJ
Quatr:.r^nany mor.aini: deposits.
_Q:, {-g ngly:qgll_-l\/j ! ri l : cr nco nso 1 i cia Le d ma re r i a I de nivo d
\ "/€ratller.ing oF ivlintr:nn bedr^ocl< nraLenial; ver.y slo,.v
dorrlinates oven r^aci<1 .
S'l:!g_i_,lg-n,.1::Qe!ll!._9ljgas._r Fine ccllu,,.'ium ro boulder. rJepog;its including
monainal deposit.:; th;.i.i- have f ailed and rrrcved clownslope; the s;ournce
rna'cei^ial hene is the unc-lenlyi.ng Mi.ni:urn For.mation.
nal*' i=lg. j-!gng_-.!J'-.!!::_
ci !y11 !:_e_n T ry_f , lly yt gl Fiili cone slr:rped cJeposit of alluvial and colluvial
secli.n'renlr; rviricfr are depositerc gu a tnibutany stream upon entening a langen str.eanl valley of hlgher orden.
found at the base
aneas cf fine-gnained slope wash deposits
steep slopes.
_4t,"!g1rrgl)1-:.lljly:logra.51hicJloodpltin: fluvial-glacial m.lrenial deposited
ir;rd newonked by the watens ol" Gone Cneek.
The Cenozoic histony of Gone Cneel< Valley, bcing dominated by exlenslve
weatlrening and stneanr and glacial er-osion, hers pnociuced signiFicant
amounts of u ttconsol idated, metasta.ble sedin-rcnts which mantle the steeD vallcy walls. z\s in most mounLlin arcas, the geologic pnocesscs ot weatherir:q, tnanspontation and nedeposiLion of sediment ane qulte evi.dent hene. In mountainous aneas nock weerLhening pnocess na_{.es ane much
incneased, and physical weathering seems to dominate over chemicai.
oOolluviunr: nock fna(lffrenLs and gnains (wicle gnain-size nange) canried
by :]5;f:f5:jf (fluvia1-gr-avitlz pnocesses) usuaily on st-eepen stopes and
deposited in pocl<ets as unsonted matenial at the base of slopes on valley floon mangins.
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MounL,.iir buii.'rlir I ilctivil)./ pnocluces rrr,Lny joinLs, fnacl,ures ancl l'aul ts
in t.hc rr.rcl< sl.i ..irjiLrne r,rrhicir o[)ens tirc i-cdnoc'-l< to .rccelenated weathenlng
proc€'.'-ri:/,:.r. A.ri.r,.,i;'.:ti11 lr;1. r;....;rnpl-ry, in1'Iuence-s t;1e iocai climate pnoducing
gnci:i-iri" i.iiil'tpci';'i {:'.i nai .';i.rri :.rirr.l grcarl-at- an.lounts oF pr^ecIpitrtion.
Motrrr'r..1 ',ir Lcrpr:rr,'.,f i^,5, ai ', e)'l .uses ri)irl^ri rock anea to weathening pnocesses.
A ttcj rirc,'r ri.;li1-1 ..,,-,,.,.';,:.{:ir-'r'. pnocl!rces or.!l .'.r ,iJ acids and c,Lses whicl-r chemically
weatJ-r.,:i' L-rc c-iri-r. I .. L nc i '{:,r'cl.:i c'' ri wcal-he.:t.iit.; p-:t'Oces;s rates, which pnovide
loos,.':, t^"rns;; ,r^ I - ;rir: nti.r irr r. iiil , occui. orr 1-he stee;; valley wails. These
steep riic'ui'rlain : i'-.;cr. rtrlr,'vicie the gr^ircii.ent essentiat 1"on fluvial and
gnavity l-ne,'.:l-r;.r t-, i .; i-r':, t-() acl- irr l;r -'.nspot-Li n91 tlrc UnconsoliClated matenial.
J-l.la d\,/r-ii'. rirics .l wr,jrJ.l-her'irrll i,.; .C enosion !^t 3 r^e have :r'Linost preclr-rcJed
tkx: c-i,.,. ..:lo|:r'r.,i,-;l- oi' '.r'e1i--il::Fin::i,i scii.s, Bt-rL lhIs i:; not to say tlri.Lt tlre
uncc r . . . r l l cl ;.' L :: c] c,.;1.l.1;'',,iurrr Lar:l<s :,:oil-1il-l:: pr-.opent:,cs, it is just- that the
coltu\l jrrrn l^r,,:s r,ct L:er.: it si:'.lrk: Fct^ Lhe L[l'rrt: (sev;:nal ['runcll^ed yeans?)
r,ecos:;:,r''),' fon L.ir:: cji': vc l.L'.,]-;r'nrr-ri of rareil.-.cf. iined soil hor,izons . This is a
coi-rc{it|otr typ i. c:-r I r-li' tt-rcr-rirtalir arcas.
An al-trncla.i-,ce o1' rncvelri.'ie m--rteni.:-1 (fr'r:nr inc!^cased weather.ing) and
suffi cicttt- graci. ;,l.s f:ir" Lrai. , )ol^t.:Lion (sl,cc'r slopes) pr.oduce nei.ocation
of ryr,ri't-ia.1:: aiL ,^..ie s c,f s1.c,, ;;-.gpsas: ri 11696itud: tlr-rt t-he pnoceSS Of
enoslon, wl'rLch r ,,,-.r.'i11i/ ccciii'.:l on Lhe g.-.:o1oglc scalc of time, begins
to inl'iti,:rrce lrtan's aclivil-iers 'rv[th gne;.'i- n anci c]reaten frequency. This
nrear,s ,.-;irt scil 6,1.3;i.r;gic rlr,{.r,nii:ls anci topognapl'ry h:.vc a ternponal
Qualit5r i.o Llrp rn ra.,l": iclr r-equi;,::s t ecogi-rir-[otr pnion to development of
human I'iabi Lar{-ions .
€ggll,r|"lll="':l:
In mour]tainoLr,s aneas the r ijles of weathening, tnanspor.tatlon and
deposition have been rrsleplted up'r Lo --quch an extent thab they occun
on a hisboi'ic tinre scale (wilhin the ral')ge of an incJividuails lifeti.me)
nathen Lhan on a ocologic Lime scale. Rccognltion oF these pnoc.sses
and th.ein erl'ecL on clevelopnlent_ can be ciassified into thnee ar^eas:
1) locat-ion of clevclopment on meLast;.,ble matenial sounce aneas
capr;11)1.a 01= movenlenl- cJowrrslope,
2> locatiorr of clevelopmenb withirr the tnatlspontation path oF matenial
capalrle of movcmcnt,
3) locaLion ol' dcvelopmerrt aL l-he sitr: oF matenial nedeposition.
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Thcse pnc)c,r:r-res combine to fonm situations r,n here metastable geologlc
nratenial c,.rn become mobile elncl move along a tnanspontaticn paLh Lo
a sta.ble sii-cr of redcpo:r;tion. When tlris occuns wlth such higlr fne-
q'-.!e ncy on iriten:;ity thaL lrumarr life on pnopeFty is endangened, it is
cal1ed ;r geclogic hazand. PoLential gcologic hazancls (See l\atunal
Ha..:;nds Map) or, 'Lhe Glen Lyon site (er.clusive of l-rydnologic and
s no,,..r l..valanclre) a r^e:
1) clubr^is s.iicJes irnd othet' slope falh:res associated witlr stecp slopes ,
2) ciebr is fl.c'uv or. f-looci-r<r la Lc d de1.,,.,sition on the clebnls fan, and
3) hydi^ccorr-,praci.ion o1-- rrsoil't on tlre coiluvial wedge on the debnls fhrt.
De'.'i^is s;iicJe.s arrr-l othen slope iail"rne:; on vcny sl.eep slopes carr occun,
bu[: 1.',: probali:,i1i L1z oF a nalunal--occuning slicie on this site is r^clati'velV
low" Addition"rlly, l-hese slicle-s ane a-qinc-iated v,/ith slopes so steep
thal: rj:v,-.:Iopment ther^e wc.Lrlcl be imp:-ar;::ical basi-:r,l on slope a.lone.
Tl-ris bnoacl gr-or.rplng o1= siope {=ailuncs ir-rcludes a nange of t5rpes fnom
vcny slorv brrt conLinuous mc;.ss-wastl, 13 Lypes, such as soil cneep, to
rapid but lnft^equent mass-wa.sting types such as landslides (See Chant
of l\u1ass-\.A/a:,li.ng 1'y1;es, trig. 4 .). Slope iailune s can occur oir slope-s
i .\F f-r! iit..''nar)i Debt'is Slidos, wf tene;.:; slope failu'n*; of the
Qunlennany Coliuvium ane less likel;r. Tlris latten unlt s;eems le s
susce;-:l-ii:1"e to rrrovei'rtent. ./'\ t any nal-e r the geologic hazand associatecl
witir debi^i.s slick:s and slopc l"ailunes on stcep slopes nanks low, based
on boLh inl'r'eguerrcy of evcnt and rnaqni.tude of evenL. No evlclences of
Ia16 -.;cale. ql66p fri lr rnr:c i ci rk'ncg 6{: SUffiCic.rrt SCale tO affeCt lvr vr, r.v., L,,vJ
the pnoposed development ;,lan, wene obsenved. In all likelihood,
what has been obsen.,zed on Lhe steep slopes of the site ane oiden siope
failunes wlrich occunrccl di.lrlng kre Q.ual-ennany, when climates wene
coolen and these slopes wer.e langely Fr^ee oF extensive stabilizing
vegeta.Li.on.
The geologic hazancJ associal-ed with dcbnis flow on Flood-related deposi-
tion o, r the debnis fan menited r11one conceFn and cJemanded mone sLudy.-The wond 'rlonnentrr is cl'ten used as a genenal Lenm fon these t5zpes o1'
,hazands. By 'rtonrenttr we nlean nelatively swift-rrroving waten, sedi-
ment- and debni.s usually moving down a distnlct dnainageway on channel .
The nernge of possible tonnenLs l'onms and theln depositional pnoducts
ls :;hown in trigure 5, trGeomonphic Pnocesses and lhein Pnoductsrr.
Debr is blows ane nelatively waten dei'icienL matenial flows wlrich consist
oF mud, nocl< and debnis. They ane somew,hat nigid flows [n whlch
the sedinrent ancj debnis l'cnrn a matniz. They flow in sunges at
nelal-ively low velocli:ies ( d20 mph.), but are capable oF pnoducing
gneat damag;e. Movement 01" r-r're tastable matenial is usualty it-titiated
by lrearlz nain stor^rns on sudcjen spning tharws, Thus, the necessany
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c}[il:.;:r1;3 wIi $Ti;\jG TYprS
M:!tcrials acctjnr(ri: l-(' conttililor-l '
by we&th.)rin'r .n{i t ,'nrr '-:T'r' i-t. t r.'r\
into n)cr:r:,tii1)1. |.j.: ritorl in
ca+.ciifi r,r1t ba:iin .rirovl) d.ainaq'r'
ln situ !^.,eat hcai,.! p|oduces
iii. i. r,,'r. rn:ttcri,rlj tn !tcc,.,
slop.r.j.
Rapid Sl),.ir-i.t M.rlt
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En rnar...; l'low on slicje dolvnslopa';
pnoiiL, ,i srnall-scal. scars or^
lange-sriale avnl.ar )clre paths.
Lamininn, vis-
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str!ctuned
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Trrrsulrlnt, l(,!s
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no structLlr'.'d
rnalss; concln_
uous flow do"vr'
drarn.\9e
cf:,rrrnel.
r'tF€-,i..t.^b, tr Ll | 1l./
cl€:l)oliited tn
trr, r:,!; ,r:; .r l('l)r-'.
aaLLuvlhL \\lvce'-
nt 1).r.,c of :,lot)a
f:rltN
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shccl $.
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FIG. 4
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ingne(J:.cints 1'o n a debnis flov,, t.o occun ane: 1) signil'icant quantities
o1' rnr.. tasl-irble nratenirl pos i t,i,..,rre cl in a dnainage basin il1 such a way.
that Ll'rc r.clea.se of the matc:i''ial i"ringes on a 'rLniggcringrr event, and
2) LnL',.,,.i'-tction of e>{cess werten intc Lhe metastable sediment by cithen
Fapid snoln,rnelt or irrte:nse na.in1'a11, thercby neducing its irrtennal co-
hre s lc'r-r ,, ircl !rtniggl':i^irtg" a slide.
A ha:-;ii.cis si:udV cJone fon lhe Towr of \/ail showeci tha,t a pontion of
the G)lr.:n Lyo,r -p, .,,;,cnty was cl.;r.sslfled ." * 1-sr.ze 1 1 , Debnis Flow
Ha::ald. l-c:vo I 1 ltas called a,.n anea oi rnode natc h:iza-nd wlrene pnop-
enly cj.rryiir.go was possible i:rirL loss of I i. t'e was unii[(ely. l],ebnis flows
werc ci: i'l-ir.::d in this st.udy i.r-s; "larninan flow(s) of stnuctut^ed mud,
det .is arrd rock n1.i:;:r.rr In i:his area of trrodenate hazanrl , debnis
f'L:,s c.rri caLtse damagc to *ctnuctu'nes by 'rei'osion, relocai:ion, inundatiorr
tr,' : rrd arr'i soil i .: rd l*ocl( inrpact.'r Obviously, mor',,: detailecl sh;dy
r.vas t^equ 1., 'ed .
A t^tirr;r' ,^,rieans, .: natt'nal ha;lLt'ci: con-s.;Ltartl, was €rlr :.,.rlccJ by the de-
rvelc[x:n, Andnew Nornis, on the neconrt'nend.rtion of The John Ryan
Cc r,^' 1--,;-.rry' and THi( As-sociaL{-'::;, bo evaluatc Ll re pnobablc nisk associdfed
wiLh Cebr^is i'lowE; a"ncl othen lrazeri'ds on the Glerr Lyon site. Means
conducled hi.s Fiel.d invesl-igaLions on At-rgust g and 10, 1977 and was
acL'.irir^rpanic, ..i by Arrcly NoFi^i:;, t.he deveiopen, Mear's exal-I1iried botl-r
Rbc!<pc.irrt Culch and Panl< Meadov,rs Gulch fo v' debnis flow hazand antl
found tlrenr sigrri.f icarrtly differi :it. Means fi::und tlrat tlre Rockpolnt
Gulch cli ainage was Lhe site of a nathen substarrl-ial, bul ancient debnis
flornr. Irr negard to pr":sent haz:r.ncl levels thene , he concludes, trRock-
poitrt. br;.;in appeerns to be stable wi.th nesltccl- to debnis flows at the
pnescrrt time'r, and r'. . . the r"e is tro evidence ibn pnesent debnis flow
potential.tr (Mean:; nepont, attached to bhis discussion, p. 6). Means
concludes that the langen P.'.nl< Mealdows Gulch dnai.6ags basin I'is
only rmar'ginally si.able'. " In Lhis basin Means Found that Lhe uppen
bas.;in, localrrrJ belween the el.evations of 9,2OO Feet and 1O'2OO feet [s
'r panLicu1..r.r'1y suscepti.ble to sheet nuno{'f ol' mud and vr'aten cjuning an
intens;e rainfaii'r, and that the lowen basin, below tl-re elevalion of
9r2OO fect "is the sounce oF the majority o1- i-he nock debnis.'r The
Natur .rl Ftazands Map sl'tows the loc.rLion and maximum extent of the
Iangest pnobable clebnis flow. Atthough Means coulclrr't pnecisely assign
a def irlite pnobabiliLy to such an event, he concluded that the annual
pnobabilitlz was rnost lil<cly less Lhan 1"/.. An event wilh thls low
pnobabiiity and low impact pnessunes (1OO lbs./ft.Z See Mitigati.on
Measur^es.) is of such low magniLude that land use alt-enaLions
otrRapicl Mi-r.s;s-w;rsting F)nocesscs, Vai1,
Towrr of Vait by Anthun lvlear s, Apnil
Colonadort pnepaned Fon Lhe
1o.77
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i; , -r l: r'1 ll: -a :t
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QoAr'vt
lll t?l i l0$
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I ii ii hc:tl\ruT Ck(n, Avilenci',
Iir i, [furr,'Ci.i; oe,!twcr['|"
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fiot l nor,t,,,,l,l,,Fil
rqt.:r-t!! 4..' :r.t ''-r\q#o,itrl
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FIG.5
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in the pnopo.sed developnnent plan are Llnnecoss;rnv. Rut, etzcn r"ri t-h
tlr,: occunrence of such an untikcly event, ol-hen mitiilatiot'i mei':;ul'es
ane requircd to pnoLect pl^openLy.
Tonnents anrj mass-wasting pnoccrsses deposit mater^ial in a nelatitrely
riundc r-cor;rpactcdtr State. These acl-ive pl^ocL.s--;eJ prcclucc co nr1.,); rni tive ly
rryoungrr mat-enial ,,vhich has not had Lhe opponlunity to natunally coml)acl
and con:;olidate li.l<e oldcrn sur"ii"ial rn;1te l i:ii. l-'le t^e traLunal cc-nrpacl'iotr
is a function of seciin-renL ager. -f l-ris cha', r'ac l.erisl.ic of Lhe sunf icial
marterials or1 Lhe Glen Lyon site has implic;rlions fot^ tl-re clevelrlpl'rrerr i
plan (See Mitigalion lvicasures).
In summany, th:: initlal concerr. of Andy I'IonnLs, the de'"ueloper', John
Ryan and TFll( Associ.ales fon thc pnesetrce atrd magnitucle of geologic
hazands on the Glen Lyon site was soon tt',rrlslated into <Jctalled site
studie,s conclucted by A r.thu r. Menrs, a nalu na-l hazards ccnsLlll-anL. His
fi.elcl investigations conflnmcd the pr e:sencer of clebnis f-lorr',, slo;lo fa.ilune,
anC soil stabili.ty hazi,rr^ds., brrt. with nisk levels much lo'rve n th;.n suspectcd.
Tlre nisk levels of l-hese hazands wene detey'mined to be low enough to
justifly the contitruance of the pnopose..l larid-use scheme, with only veny
minon and neascnable mitiqation nreasunes.
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I DEBRIS FLCi'i lrilTl Sil0i{ AriALAl,lC}lE llrrZ,liil
Ai'l,AL'iSIS lliTll ASS0Cii.,Iil LAii!-l.lSl
P,EC0iii{[illAT I CiiS
PREPARED OF:
lirt, Alnnrw I'loti,.rt s,
GonE Cnrrr Assoc I/\TES
GeoiOgi.c Surpp're:i'r :1. rrl, Appeniii.:< A
Anrnun L liEnns
Auousi 1977
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I. SLT,1i''\i{Y OF STUDY
Debris f loros ocr:ur in thc l:rrk lie:r r,lr_r1,, cir;rinage b;rsin abovc r_r
porLion of Core Creek r\ssc.rciates propt:r:ty in \rrti.1, CoJ.oratjo (Irigu::e J_) .
Thc f.l.or,,s can rcach tl:c upper part: of Lhe dcb::is fan, as inclicaLed otr
).1ap 1, a1l-hough the estim;iLed a..nnua.l. probabi.l-j t:1' of s;uch cvcjnt!; is
1 percenL or less (thc re:urn peliod is 1C0 yc,;rr$ ol: nore). Below Lhc
indicatcjd haz't',rd a1'ea the probabi llt-y of d.bris f Lorv occ,,rrre,.nc.: is
rrcgligible and can be ciisrcgardecl .
Debrij f lorvs do noL jlrcscnt z hazard rl.n the Rocill-ioint d:-elnl1,c
basin.
Snoir aval.rnchcs occr,t. in the parli l,icadovr drainage b:rsin '1,. f
arc lii.rif ed in arcal ey.t(: L and oo not i.f !ccL It.opc,sed dcr,clop;nc.rt cn
rlie debris fan. rn addition, one snrall srrora avali:ncjre area hiis been
ide'l-ified appi:oximately 200 to 300 f t_ct ioest of llockpoint Gulch
bctr";een elev.rtions of appro>:i.rnate1-y 8300 and Bi50 f eer:. This aval.:rnc,i;:
moves at 1ow vclocities ar.l produces s;nal.l to noderaLe irLpacr pr:es:jr.rl: cs.
II, RICO}J],IE}IDATIONS
The f r.,llorqing reconmlendatioris consi.dcr the physic;rl clraracLer-
istlcs of the dcbris flovi ar.td snoiv avalnnche nrocessps arrrl ll)e antic.i-
pated use of thc property iD and ncar: tlle- potcnLia1 hazar<'i areas,
1. Residential br,ii.ldings ccrnsLructeci in the debris f 1ow
hazard areu (lfap 1) shouid be prote ctccl againsI the
f orces prodr.rccd b1' a moving debr js f lorv 5 f eet high,
having a unit rvcight of 1?5 fbs/f 13, f lor+ing at a veloc ir..'
of 5 fr/scc. The lorvcr 5 fceE of r,rphill building w:rlls
or f oundations (includ ing wir.rdou's) should be designccl t <_r
r.ritlrst:rn<1 :r cl;,nnrnic Prcssr,u:c- of 100 lbslf t2,
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2.Stable, old debris 1:iL' deposits c'n bcconic unstab.le through
inproper use, procluce l.ocalizccl soil nrovements and small-
slldcs, and possi.bly c:ausc damrg;c to foundalions or other
struclures. To nrininize tlris problern, decp cuts into thc
debrj,s fan, within and belorv t:he dcbris fl.ow hazarcl area,
should bc avoiclcci. SiLc-.spccif ic_soii_$tab j.f ity test.s
shou.ld be requircd aL consEructioD sites so Ehat quantiLa_
Eive data arc av;riJ,abf e with rvhich to assess loca1 grouncl
stabilit)'. Furtherntore, j.t: is strongly rccolnmencied thnt
lat.,''n watering over broacl areas be <liscouralged because
water-sa1-(lrated soils are nore susceptible to shear fail_
ures and slides.than dry soils.
A drainage p1-an shouJ.d be incorporated into f i.na1 planning
of the deveJ.oprnent (one rvas previously reconnended by l{ydro_
Triad, Lrd., in I974). Ilowever, debris flow deposiLs on
the uppcr.' fan can gr:ea cly alter the constt:ucted drainage
channels by sedimentittion, and rcsulL in a random disper_
sion of any subsequent flood waters, Thcrefore, to
ninimize r,rater f f ood darlage bcl ol,, i,he dcbris f 1ow areil , lhe
responsibilicy for cleaning debris from the upper fan area
should be assumed by some specif :ic group, homeorqner,s
associaEion, disLr:ict, or govel-nnlcnt, !o insure ntainEcnance
of a function:r1 drainagc system.
If consLrucEion within thc linil-ecl snow ava_lanche area is
necessilry' br,r:ildi'gs should be rlc.sig'ed to r,/lthsitand the
dynamic pressurcs rcsult ing f rorn avll.anche impact. I\rithin
Zotre rr (IIrp J-), Lhc lorvcr r-2 f cct of uprrirr buirding rv:r1rs
1
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( i n c 1 r r i.l -i- i r i; rvinrlc,r:r;) shorL ill L', clesigncd to resist iI prcs:jurc
of 300 lbsi/j:t2. lr:. ir.ont: i tlt0 lor.;cr B fcet shoulci bc
clesilircrcl to rcsi.i.;L a l)lrr.r:r:ruir() of 200 1.bslli.t2. Both
rcquirtrr.lrts it..liiuii'.i:: tlrc lril j i,1i Dg r.ra J-L i.s perpendi cular to
tlte av31.:rrrchc f 1ol;. 'i'li.c, l: (:t il I I.i. r- c cl p.Lus{lr.lres .rnd loads
could i)e redtrctril iI a cl:i f]f (,]-l;1t building orienEation with
respccL i c-i f low i.l; r.rs:ecl , lt(i\ri,rli.lr:, inCj.v:irlua1 corrsr-rlting is
requir:ecl to del-(,i:nrini: tlier l.o:rcis arii clj:rcnsions.
IIi. C1]0L0GIC COlitiI:iT.tl];s Alii) ,fliu i)iillii.i rir Ir,ol^i ]tlr0ct:ss
The area $ Lud j e-d i:; locntccj :,:; j nd j.ca ied cn Figure 1. Tr+o
intermitLenL streans riischargc \.:i., i:l: an(l/or dcb::is onto l l-r e property
f rorr srnall drainagc basins on tho. nnr t.lr-r.;r,s L f acing valley wal1 of
Gore Crr':ek. Thesc s:nall dr:ainagc baL:ir-L.s \!'et:rr narl.C Park }leadorv Gulch
and RockpoirrE gulch in a prerriotrs s t.uciy bi' I1y<iro-Triad, Ltd., (I974) .
These nanes are rct.tiincd f or u:;r: 1n tllc pt:crsent stildy,
Ttie Park l'{e:rdor" ald llocl.lpoi'nt dr::tinate basins 1ie enrirely
\^/iEhin a complex of l;edjnte ntaly rock rrr: !,-s knor'rrr cdllectively as the
Iflnturn Irormati-on. This f or:natic,rrL consists c)f a mediirn to vcrv
coarse-grail)ed Sr:ty to redCish-br:oi.lir sAprlcrnn,. r-rTrro lnnroreric sandstone
with fhln beds of recid:islr-bro,,,'l sllLstcne, sj.rndy and sil.ty shalc, and
pt:omj-nent pinkish-gray to gray lj-ncstorr,-: bcds (Robinson, 1975). l^lithin
the Park lleadorv Gul-ch drainirg€, unconsol.irlati:d and unst-abl.e deposiEs
resul.t fronr localizcd rreatlrcr.lng, erosion, and mass-wilsling of tlle
bedroclc units. Thls produccs rnud<ly soils '"vith a high clay content.
Ovcr a pcr:iod of yc:11-s the deposits of nii.rii,. rock, i]nd clcbris slide
shorE distanccs to posiEions of rclativc stability. 'llhcse relatively
stablc, or rrurotastilbl.c" positious cxisl \v.ithill thc b:rsin ol1 areas of
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1oca1.ly rcduced gradicnt, anrl cspc,cially w i Lliin clrrrnncls, Ilos I of this
gradurl movcmcnt r)ccurs durir:r: 1,rt_e spring, ;,nd car1.y sulnmcr \./lrcn LItc
snowpack is melfing and the soil is mobil.e bccause of a high rv;tter con-
tcnt. 0vcr a pcriocl of years the .,".".r,rr:y conil j !ions rlcvclop f or
a potcntialJy largc rcleasc of dcbrjs during an intcnsc rainfall
even f .
AlEhough accumulaled deblis is ;r r-ecessarl' condition for
debris flow initiarion at \rai1., it is prol:abIy not o sufficienl condi-
tion alone. Excess water musl also be present to ptovide the lubr:ica-
<rL) r.'- trcbris ritobil icy'. The cxccss .watcr n)ay res'.rl.t f ro:l
a very rapid snor,rmcli runoff during a pcriod of hot spring wcather,
or from an intense rainfall. centered over a snal.1 area of the basin,
WiLh the combination of avallablc \,rater-saturated debris
resting jn netastable posirions and sufficic:rL frce waLcr addcd to it,
debris f lorss will begin, First, soil ancl roclt rcil1 slide, f1ow, and
avalanche from previously netastable (now unstarblc) posi.tions lnto Lhe
central gullies and accunulate to depths of several feet or more, This
will occur primari.ly in Ehe debrj.s flow sourcc area (Figure ]). These
new gul1y accumulations r+i11 dam the f .l or,' of r"/ater until thev become
resaluraEed. Debris f lor"'s will begin in tlrc main gullies rvhen
amounts of water sufficient to reduce intcrna1 friction of the debr:ls
is added Lo it, Ifltcn this occurs, debris r.'i1.1 rnove do'"vn Ehe gul1y as
a disrir-rct surge or plug, producing very high inscanEencous peak
discharges.
Field invcsfi lrfionq of
basins wclc made on i\ugust 9 and
d if f erenccs exis t bc Lr.,'ccu the two
tlic Pcrh Mc:rclorv and Ilockl;oint drilinagc
I0, I977 .rLrd shorvc'd tlrat signif iccnE
basins ir-r terrls of tllcir relacive
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susceptibilities to dcbris f .[ow folmati<-rn, ltockpoinE besin a1t1>cars
to be stable with respcct to debris flows aC the prcsenL time. A very
sma1l rrolume of meEasLable dcbris l,ras found. Alt:houglr an ancient
flow reached Gorc Creeh, Llrcr-e is no eviduncc for prcscnE debr:is flow
potential. Furthr,.rmorc, the old ch:rnne1 crn adcquate.ly serve to
convey fLood watel:S lhrough tlre property j.t"rt,J Gore Creek.
Par:k Meadow dririnagc l>as j rr is crnl.y "rnarginll.ly" sEablc.
Active soil creep is procecding on a najority of che 30o to 40" slopes
raithi-n the basin. rn some loczrtions boulder:s have been transpor:ted
into the main channcl and there is evidence thaE othcr rocks and boul-
ders are located in meLastable positions. The lower basin, below
approxi rate ly 9200 feet (2800m) elevation is Ehe source of rhe nrajority
of the rocic debris (Irigurc+ 1). The upper basin, Iocated between the
elevaEions of 9200 feer and 10200 feet (28C0 to 2100m), is parLicularly
suscePLibie to sheet runoff of nud and r^'"rer: clurins :rn i:rtcnse rainfall.
Much of this matel'lal r,zill run off as viscous slurries, will f1ow down
the nain channel and encounter rocks and debris in the lower basin,
All of this material can combine, mlx, and n:ovc d or,vn the channel onEo
the upper: part of the debris f :rn as a debris f l_ow. It is not possible
to assign a clef jnirt: probability to thc occtrrrcncc of tIe srrclr ;.]n ovnnf .
b'it iE is doubuful tlraL Ehe probability is aiiy greatcr than that of the
design nragnitude storrn (defi:recl prcviously by }lydro-Triad as having an
annual probabilit.y of 1 pcrccnt). The irrob:rbiriry of a large clebris
f low event pray be less than 1 per:cc:nt.
IV. SNOI.J AVi\I-ANCliliS
Snor":tvalauclrcs r:c cu r
rlra inage btrsin, llorurrvcr, dtrc
at nrany l.oc:rt j ons wif h jr.r tlre Park Mcadow
co thc topogral'lh-ic conf ilirrr:ation of the
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b:rsin, vegcLafjon covcr, and expr:cf i.d srtor,rltacli concl:if ions, a ltrrgc,
cohesive slab will not be simult:urcrously rel.eilsecl from:r largc trrca of
the basiu. llecause of this, avalanches r"'il.l be snral.I and uil1 genc:ra111'
sEop in the cenEral gulJ-y. During cxLrcn)e conclitions avalanches may
reach the rnouth of fhe Park lleadoi.i Gulr:h at an clevation of apprroxj -
mately 8300 fcet. They rviJ,l not corrstittrte a ltazarrl on tlrc debris f air.
A smal]- avalanche area was also idenLificd appro>:imately
200 to 300 feer r,'esc of Roclipolnt Culch (llap 1). The avalanche rvill
begin in and just beiow thc aspen f oLc'st on slopcs of 30o to 32" as
either a wet snorr avalanclre (a point or r{et slab releasc) or as a dr:y
slab avalanche. Even duriug extrerne conditions avalanche clcpth will
be small and rnaximum velocity r,zilf not e:<eeed 20 mph on steep slopes.
The avalanche rvill stop after c'oissing Llte open meadow belovr the
starLing zone and peneEratj-ng approxinately 60 teet into Lhe next
aspen s tand.
Arthur I. Ilears, PIi
Gunnison, Colorado
August 24, 7977
REFERNNCES
llydro-Triad, Ltrl ., 1974. Dr:rina1lc :rnd flood 1>1nin str"rdies;, Core Crcrck
Propcrlics, Vail, Colorarlo. (Iicpr>rC prc|itrcd for Seracusc-
Lar^rl.er ancl Partners, Bp, )
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Mears, A. I., 1976. Gu jdtrl:t:re:; arrrl ruc:t.hods l'()r clct;)r'-l-ed s;norn' avrtlatnche
hazarrl ilrvcstigrtion in Color:tdo. Colo. Ccol. Srrr:v, 13ulL 38,
125p. , I)cnver.
Ilears, A. I., and l^1, P, Rogcrs, ( j.n prcp. ). Guidelines and criceria
f or the an.ilys is of haz;rrd f Lon torrcnts -in srna1l nlountain
waterslreds.
Robinson and Assoc'.irtes, J.975. Folio of gcoJ.ogic land-use m:rps, Eagle
County, Co1oradcl .
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APPENDIX B
I
SNOW AVAI-ANCHE HAZARD SUPPLEMENT
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Avalanche [-la;:and Supplement, Appendix B
SNOW AVA LANCI'IE H,A\ZAI1D SUPPLE/\AENT
In montane Colonerdo, snow avalanches ai^e the most widespt-erad and
senious of the natunarl hazancis. Rect^c.rl-ionai pncssunes and nesulbant
development, rnostl5r confined 1-o the vallelr f,Loor's, have bnought manrs
activibies lnto aneas wlrich expcrience snow aval-atrches. Avalanches,
as used hene, have been defi.rred as 'rs;now and/or ice falling-, flowing
on sliding napidly clcwn a slol-rc unden tlre for-ce ot gnaLvit5z.'r1 In
addition, the INSTAAR report .'jLresses Lhe magnil-ude of the snow
avalanche prOblem wl, en il- cgncludes, Itv;henever sllow Ocquns On steep
slopes the pgssibi.lity of an avalanclre is presenL.rrz
Genenal Aya1an$e S,eLttngs and Types.
Snow avalanches can occun in ti're Vail anea in sevc:nal natunal settings
and take sevenal differ ent fonnrs, deperrding on tlre mechani.cal propentles
tresent at the time of initiati.on. Snow avalanclres can occul in u,,'e ll
defined gullies on channels whi.ch consi.st of an uppen tree-less elehn,ent basin wher.e snow accumulates and begins to flcr'v',/ on slide; a middle
r?tnilgkrr ot chute, the steep slope down rvhich the avalanche moves and
gJins vetoci\t; and a lowen nullout zone , usually an anea of lessen slope
on Lfle valley floon whene the snowrs encrgy is dissipated and the
avalanche eventualiy cotnes to nest. Snow aValancht:s can also Occun On
unconfined (non-channeli.zed), nelati.vely bannen' steep slopes, and on
unconfined, modenately timbened, steep slopes.
Genenally, snow aval;:nches can be classified into haro types, :]gq
avalancl.teg and loose snow g]snchei: Slab avalairches ane usually
the pnoduct of veny cold temperatunes ancl stnong wlnds. They possess
gneaten intennal cohesion than loose snow avalanclres and develop
fnac tunes on shean zones along whi.ch movemetrt takes place an,:j which
can exbend down-slope greal dlstances. This fnactune or shean zone is
usually the nesult of localizecl incompeterrce due to clepth hoanr on a
bunied sun cnust. Slab a''zalanches are usjually charactenized by lange
'lttEvaluation of Lhe Snow Avalanche Hazarnd ln the
Eagle Count5r, Colonado" by INSTAAR, Utrivensily
lr4adole, A. Means, et al (1973), p. 2.
-Ibid, p. 2.
bgp$--!gg5 is a t5zpe of tempenatune gnadient metamonphism in which
extnemely cold ain LempenaLttnes pnoduce a steep tempenatune gnadient
in the snow coven. This tempenatune gn.rdient causes a necnystalliza-
tion pnocess to ta[<e plarce in the snow coven whicl, nesults in necJuced
internal colreslon.
Valley of Gone Creek,
oF Colonado, R.
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stanllng zones. Finally, they can be Funthen subdivided acconding to
cohesive pnopentle s of tte post-avalanche snow condition in the nunouL
zone. I1' the snow nemains babulan and slab-llke in tlre runout zone, iLrs
called a hald sl?b avalarrche, and. if this chanacten is lost, it's called
a so1't slab avalanche.
Loose snow avalanches possess less intei^nal cohesion and have smallen
startii-rg zones. These avalanches form unden conditlons of less cold
tervrpei ;Ltunes and liLtle wind. Loose snow avalanches seem to begin as
loc;z',lized failunes at a point high on a steep slope and move downslope
ir-rcr,': 'ponating acJclitional snow and ga[ning greaten velocit5z as they move.
Evcrrturally, the loose snow avalanche fonms a lobe fnont which spneads
ouL and dissiprrtes enengy at it tenminus. As in slab avalanches, loose
avalanches can be subdivided funthen into dny on.powden avalanches and
u/gl-a\rap!ghe:. It shoulcl be emphasized Lhat the subtypes of slab
avalanches (soft and hand) and loose snow avalanches (dny ard we t)
repnesent end points on a spectnum of possible ph5zsical conditions, with
rr"rany intenmediate positi.ons possible. Also, Lhe mechanical pnopenties
of an avalanche can change duning the avalanche event, e.9.r slab to
powde r. avalanche. Table 1 displays the chanactenistlcs which distinguish
dny on powden avalanches fnonr wet avalanches.
A connelation beLween the uatunal setting of the avalanche (avalanche
chute on unconfined slope-barnen on timl:ened) and the avalanche $rpe
based on mecha.nical pnopenties, seem Lo be lacking. Slope aspect,
snow stonm t5rpe, snow pack metamonphism, and local weathen conditions
affecb avalanche type mone than natunal se[ting.
Assessing Avalanclre Hazand Risk
The common measunes of avalanche nisl< ane netuln interval and impact
_prg:slllg. In the absence of long-tenm histonical neconds, such as in
Eunope, neturn intenvals ane slatisti.cally estimated using tnee-ning
analyses on dendnochnonoiogy, based on the assumption that tnees
damaged by avalanches ttnespondtt by adding nesponse wood, which can
be detected with a tnee bone sample, This method dates past avalanche
events, but its use is limited by the age of the tnee sampled and an
inability to constnuct long-tenm ovenlapping tnee-ning pnofiles. Dendo-
chnonology is of little hetp in neliably delenmining long netunn intervals
gneaten than say 50 to 60 yeans, because of the diminished sample size.
Impact pnessunes ane usually calculated by two methods. The finst
rrelies on a calculaLiorr ol' the maximum pnessune necessany to pnoduce
the bnoken Lnees seen at the avalanche si.te. Tl're second nelies on a
calculation of the volume of snow most lil<ely to be neleased. Then an
assumption is macle about the type of avalanche most likely to occun
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I Dny on Powden Wet
I - usually fonm during napid - usually fonm duning spning thaw.
accul'r'lulation of snow, as dun-
r ing a stonm.
I - intennal cohesion can be ne- - inLennal cohesion can be neduced
I duced by depth hoar'. by melt waten.
I - fluidized, low der-rsity (1o-2o - nigid, high densit5z (3oo-4oo ug/m3)
I Xg/rng) mixh.rne of snow and air. mixtune of snow and waten.
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-velocities up to 2OO mph (nange - velocities up to 70 mph (nange
I fnom 1OO to 17O mph in Vail.) fnom 30 to 50 mph in Vail).
I
- tunbulent f,low, such as flowing - flows as a compnessible solicl .
I waten on ain.I
- tnavels high above the gnound - tnavels lorv to bhe gnound ( ft.
I (2O fL. avenage, but up to 12O ft.) avenage)
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- impact pnessunes usually lange - impact pnes:iunes usually nange
I fncm looo to 2ooo lbs-fft.z, but fnom 2ooo to 35oo lbs/t('
t can neach 4ooo lbs,zft2 in the
nunout zone.
t - nunout distances nange fnom 650 - nunout disbances nange Fnom 50
to 1350 ft. to 5OO ft.
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Table 1
Loose Snow Avalernches
AVALANCHE RISK MEASUREMENT SCHEME
-(o 15
RED
( HIGH HAZARD)
-,
- (,2
BLUE
6t.
an €
UJ
E,f a a
UJ E
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=
(. Vai( Moadoua (fou&a)
Z.A\oyzz 'A't'P' VaaTw (Wd)
z .CL ubtnoau,, W{eria\, old AuUl G^lpr.)
*.lvuVexra\o ((orser )
5 .(wilqv, Q',&-w,vler, 6, lhq { u r6,a!o"lw\
6.6i'rq"Af.hor /Faudo'r) I' I
WH ITE
( LOW HAZARD )
! (MEDIUM HAZARD)?-hot hToir* cculoh Ava l lnc,ha
100
RETURN INTERVAL (years)
200
FIG. 1
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' and its physical and mechanical pnopenties. The avalanche velocitles
and ultlmately the avalanche impact pressunes along the slope and [n
Lhe nunout zone can then be deter-mined. These two cniterla, netunn
intenval and impact pressune, ffidy be used in combination as one measune
of the maqnitudc of the avalanclre hazarnd risk. The Town of Vall has
j-adopted'l de facto, l-his rrcasune o1" risl<, modified aflen the Swiss systern
and has iden[ifiecl ned (high nisl<), blue (medir-rm nlsk), and white (low
nis[<) zones. (See Figur.e 1 Avalanche R i-sk Measunement Scheme.).
Avalanche Hazands*of Gone _Cr^eek rqelley
GenenaLly, avalanche hazands of the Gone Cneek Valtey can be gnouped
lntu sevenal bnoad "niskrr categories accor^dlng to the degnee of nisk
anticipated and the amount of specil"ic avalanche infonmation known.
La Chapelles surr'ntanizes these categonies as red and blue zones, which
are the classiflcations given to tfre majon gullies between the junction of
Gone and Black Gone Cneeks and the Clubhouse Slide. Ant Means
concludes that these rtconstitule the maion avalanche hazand in this
valley. rtu Most of bhe avalanche chutes have been examined in delail
and assigned to nisk categonies based on estimated netunn intenval
and impact pnessune. Anothen categony called, by La Chapelle, "zones of avalanche influence - mone detailed studies nequired" has been applied
to avalanche chutes principalty on the nonth-tacing slopes, which lack
detailed sLudies but still presenl- a significant avalanche hazand based
upon tennaln analysis, catchment basin size and chanacten, and pensonal
expenience of long-time Vail irrhabitants. In aneas unmanked by discnete
avalanche chutes, the categony rrzone of avalanche inflr-rence - mone
detailed sh-ldies requinei" has been applied to steep, nonth-facing slopes
on which sma.ll to medium avalanches can occun. On these slopes snow
may accumulate in small openirrgs ln the Fonest on in open fonest stands,
and upon nelease move nelatlveiy shont distances down-slope thnough the
tnees. This is the cunnent avalanche hazand classiflcation of the Glen
Lyon pnopen$r. Tlre finai nemaini.ng categony, which La Chapelle calls
rracceptable residuai nisk" has been applied to veny low avalanche hazand
aneas, which which whlle not entinely avalanche fnee, pnesent such low
nisk that avalanche dangen lrmenge(s) inlo tlre backgnound nisks of
societ5l.tt7
4Avalanclre Mapping and Zoning Pnoblems
Edwand R. La Chapelle (July 'l 976), p.
vlDro. , p. 2.
Qxsraan (1e7G) p. 19.
7La Chapelle (1976) p. 3.
at Vail, Colonadott by
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APPENDiX C
AIR QUALITY SUPPLEMENT
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Ain Q.ualiLy Supplemerrt, Appendix C
AIR QUALITY
The climatological chanacte nistics 'of the Gone Vatley dinectly influence
the air quality of that anea. Meteonological and ain qualiLy data con-
tlnues to be gathened, and studies ane underway which. should funthen
define the panamebens ol= ai.n quality in the Gone Valley. These studies
ane due to be completed duning the fall of this ye.ln.
The infonmation pnesented here is a compilation of the most necent
studies and data available. New data was not specifically galhened fon
this nepont. The conclusion of sevenai studies cunnently undenw,ay,
panticular'ly a sterck sanrpling stucJy, should add some detai.: necessany
fon adopting appnopniate mitlgatlor measunes fon ai.n qualit5r irnpnovement
ln the Vail area.
Genenally the ne ane two diffenent $zpes of ain movement in the Gone
Valley: those associated with negional aln masses, which have a pne-
vailitrg west to east dinection, and those associated wlth local diunnal
ain pattenns consisting of upslope and downslope wlnds.
Climatologicai data has been gathened in Vail fon wind and temperature
for 1977. RecenL wind data was obtained fnom a monitonlng station
located at the Town of Vail City Hall fnom Novemben, 1976 thnough
Manch, 1977. Tabies 1 and 2 summanize thi.s data.
Table 1
Wind Dinectlon
(Measuned fnom the Nonth)
Month Maximum Minimum
Genenal
Dinection
Nov. t76
Dec. t76
Jan. t77
Feb. t7-7
Mar, 177
3550
350c|
350()
3500
3550
.50
2c.0
100
100
50
Avenage
157.90
14s,10
198.30
182.50
fig.40
SE
SE
SW
S
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Maxinrum
Table 2
Speed in MPH
Minimum Mont:lr
Nov. '76
Dec. r76
Jan. t77
Feb. t77
Mar. 177
Nov. 176
Dec. r76
Jan. t77
Feb. t77
Mar. t77
20
17
l5
20
1
1
o
o
Avenage
4.2
Z+.U
3.8
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Thi-e matenlal shorvs tl']at stnong winds associated wi.th stnong negi.onal - ,ain mass movenrents ane pnincipally fnom the west and nonthwest.;4, a)':-ta-',
T'he daity diunnal pafter^n conslsrs genenauy of upslope ;;a.;;';- ao*'lL'o
'the clay and downslope wincls in the everring and eaniy monning houns.l
The latten occurs Ll'rnoughou! the year^f with weaken winds ge nenally
occunning in the monning and increasing in the aftenrroon.
Table 3 iilustnates necenl tempenabune data fon the 176-177 tlrne
peniod.
Table 3
-I-a rn nz: n: tsr ry.a /FOr )
Month Monthlv Maxlmum
510
449
560
520
Montlrly Minlrnum
^^o -12.ro
-40
1o _40
Avenage
25.60
19.50
19.50
ae qo
25.70
4oe
netenned
Mantha
I lDaytime neFens to the hours oF appnoximately g a.m. to
5 p.m.
tflir infonmation is slpponted by bhe cli.matological data
in the nepont, 'rAin Quality Anaiysis - Vail, Colonado'r,
Wood, F.A. Flowand, W.E. Manlatt, July, 1976.
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The pneviously discus.sed climat.ological data, low wind speeds and
cool tempenal-unes Logethen wiLh low mixing heighbs, combine to pno-
vlde the conclitions which seem Lo occun most fnequently when state
and/or fedenal ain quality stanciancjs ane exceeded.
The disl:enslon of poli.u l"ants is often limited to the lowen
pontion of the almo:;phere by meteonological conditions and
the mixlng lreiglrl is cJefined as-; Lhre disLance above whlch
little dispension occun-s. -fempenatune invensions ane fne-
quently tfre del-ennrinarrts of Llre effective mixing height.
An ain Lemoenatur'e invension occuns when wanm ain is
undenlain by colder^ ain nean the sunface. Since the colden
ain is nrone dense, the con'igunation is quite sbable. Pol-
lutants may be tr^apped by a tempenatune invension and this
condition is panticular.ly sevene in mountain valleys since
honizontal disperslon is limited by valley walls. Veny
shallow mixing lreights have been obsenved ln tvestenn
Colonado mountarin valley (Howand, 1976).o
Data was collected in the finst thnee months of wirrten, 1977 nelated
to invenslon occunnence, fnequency, height, and clunatlon i.n Vail.
Duning the thnee months, on the a.venage thene we r',e only thnee days
pen month without tempenahrne invensions.
Table 4
Invension Occunnence
Month Days _wiLhou! invensi_on pjegelt
3
2
Avenage 3,/month
I Januany
Febnuany
t Manch
I
r The tollowing Lable illustnales lhat 'rnvension heights can be veny low
I and that the mean dunaLion oF in,,'ensions is appnoximately 15 houns.
3'tAin Qualib5z Analysis, Vail, Colonadott, Mantha Wood, E. A. Howand,
W.E. Manlatt, July, 1976.I
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Tablc 5
Invension CharacLenistics
r Invension Djrnation* Maximum l-l'eight** MjfLlf!'I-l-'leiglrt** A,zglg-ge-te-!gE**
I Mean Std. Dev. Mean Std. Dev. Mean Std. Dev. Meatr Std. Dev.
t?: i: ;t .;!:J;"
368 64
350 53
355 30
156 34
112 38
136 s9
2BO 44
273 34
2A4 23
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The heights of inversions appeat^ l-o be lowesL duning the veny late monn-
ing, aftennoon and eanly evening houns.
The following table illustnates the fact that mosl lnvensions begi.n in
the late aftennoon and eanly evening houns and end in the late monn-
ing and eanly aftennoon houns.
I O.lJL(t t
Invension Onset and Bneal<up
Month Invension Onset %Invension Bneak-up %
Januany 4 p.m.-7:3O p..m, 85% 10 a.m.*3:3O p.m. 59%
Febnuany 4 p.m.-7:3O p.m. 79% 'l O a.m.-3:3O p.m. 79%
Manch 4 p.m.-7:3O p.m. gO% 10 a.m.-3:3o p.m. eO%
I -. At centain times oF the yean, the ain qualit)z of Lhe Gone Vailey is
I tf6"9;below the desinable Fedenal and State standands. This occuns most
frequently in the winten monLhs when invensions occun most often.
I In the summen, when Ure tempenatunes of the valley sunfaces ane
I highen, l-he dunation of invensions is shonten. Fedenal and,/on State
Ain Qualilry Standands ane mone frequently appnoached on exceeded
I duning invenslons in lhe winlen monLl"ls.
I Fedenal and S tate ain quali,by standands for panticulates ane pnesented
I in the following table.
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Table 7
Ai.n Qualib5r Standands fon Panticulates
Fedenal and S Late
(micnognams pen cubic meten) mg,/m3
Fedenal S tate of
ffi Eeconclar"v'.* Colonado
Annual median avenage 75 60 41
I Maximum 24'hour 26'A 15O 15O
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Notes: * The pnimany ;tanciand is to pnotect health.** The secondany sbandanci is to protect welFane.
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APPENDIX D
WATER QUALI-TY SUPPLEMENT
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Waten Q.uality Suppletrrent, Appcrrclix D
WATER QUALITY
RunotF from developed "trnban" aneas cannies pollutants which come fnom
rool=tops, gultens, pavement, ard othen lmpenvious sunfaces. These
polluLants, when cannied dinectly to a stneam, panticulanly at times of
low flow, contnibute to a detenionation in waten qua1it5r. As pneviously
discussed, snowmelL on the valley occuns pnion to the rrnegion-wicle
snownnelbtr and entens the stneam when it is at a lowen flow, theneby
having a gneaten impact. The degnee of this impact [s also gr eai:ly ln-
fluenced by the tirne intenval fnom the last nunoff. The Gone Vall.ey is
subject to longen intenvals than sorne aneas in that colcJ witrten months
may pne\/enL nunoff fon sevenal monlhs. A Lypi,cal example cf nunofF
chanactenistlcs is shown in Figune 1. The specific land use assoc;.ated
witlr centain t5zpes of development is also a ver y signiFicant delermining
faclon.
Estimates of pollutants in sunface nunoff fon a melnopolitan ar-ea
I shown in the next table. They should not be dinectly connelated
I the conditions at Va[I.
Table 1
RUNOFF CHARACTERISTICS OF SEPARATE STORM RUNOFF1
(Values in Millignams pen Liten)
EO
Pollutant
Suspended Solids
BOD5
coD
Total Volati.te Solids
Suspended Volatile Sotids
Phosphonous as P
Total Nitnogen
Chlonides
lttUrban Runo l'f Management Planrr, Cit5z of
McLaughlin Engineens, August 1973.
Unban Anea with
25 Pencenl- ImDenviousness
300
20
150
110
BO
o.7
e.l
100
Aspen, Wnight
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BU}.!OFF C${ARACTE!q8$T!CS
ll0
0.5
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}.
t/l
e
o
z I
F (.,
o z
7
o
z
()
X o
0
I u,lt StNCt
l0 20.
t \5I li/'ll.ltAt[ (i<'yJ
Increase of U0D and C0D
In Sol lds Sanrplcs wl th
E I apscd T inrc s I ncc las t
concentratlons
I nc reased
tlalnfal| ( l2)
F!G. 1
I
- In this neport fon Aspenf all of the above except chloridcs wclc
I found in vanyirrg amounts in the sur^face nunofl'. The following t;.:.ble
I lusti^ates the concentnal-ions estlmated l'on Aspen. These a,lso :';hould
not be dinectly connelated to Vail.
I Table 2
Pnobable Aspen Pollutant Loacl to Roanlrrg Fonk Rir"zen
in One Flour fnom Runoff Res'ulling
fnom a Mean Annual Stonm Havlng a l:nequency of
Occunnence of Once Each 2.3 Yeansx
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I Pollutant
I 333'
Kjelclahl Nitnogetr
Pollulani:s in l Flr.rtr n Concenl-r'i-','tion
Settleable and Suspencled 34,OOO lbs. 1562 n1g./l-iten
34O lbs.
7BO lbs.
53 lbs.
1DE rrrrr./l ifon rgv || r!,/ |_rev.
2BO mg,/i-iten
19.4 mg,/L-iten
I Phosphates 26 lbs. 956 mgl|-iLer
t Total coli.fonm Bactenia e+oxtold B8xlolcr
I *Designing tneatment fon the 2.3-yean fnequency stonm nllrtoff is
expected to include BO to 90 pencent of those pollutants which woulcl
I be tneated by designing fon the 1OO-yean fnequency stonrn nunofi.
I Based on 6000 equlvalenl- populalion, I Ac-ft. nunoff.s
I In addition to the above, heavy rneLals ane also pollubanLs which ane
often cannied to stneams by unban nunoff. The metals conslst of zinc,
I coppen, lead, nlcl<el and mencuny.I
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APP[.:I.JDIX E
TRAF:FIC CCLII..I-T DATA
I Tnal=fic Count. Appendix E
I
A m;rnLral Lnaifilc ccunt was penl=onmed fon the South Fnontage Road
I at Mattenlronn Cincle on Fniday, August 12, 1977, The methodology r usecl by the Colonac.lo Di.vision of Highways fon a manual tnaffic count is as foi [ows:'F
I a. Cou,tt Lwo-way tnaftic between B a.m. to 4 p.m.
I b. Multiply (a) by two fon the 24-houn volume.
c. Multiply (b) by a facton, depending on week of
I yean and noad t)pe. Sevenal noad types ane illustnated:
Ro,:tl T)4ce
I 6 Ccnsistent, low volume
(e.9., rrfanm-to-manket , a cit5z stneet)
7 Low volume (less than 75O vehicles pen day)I necr,eational
3 High volume, milclly necneational
I (I-7O at Vail, on a fnontage noad)
d. Resulting figune is the Avenage Annual Daily Tnaffic
t Estimate (ADT).
I Exhibit No. E-1 contain-s the wonk sheet used fon counting the vehi.cles
I and thein classification. Exhibit Nos. E-2 and E-s summanize the
tnafFic movement obsenvations at the T-intensection of the South
I Frontage Road and Mattenhonn Cincle -- a location nean the planned
t entnance to SD4. Tlrene ane six possible movements. The langest
numben obsenved was 1,O93 vehicles moving fnom the west to the east.
t Exhibit Nos. E-4 and E-5 pnesent a sepanate count of motoncycles
and bicycles not included in the vehicle count of automobiles and
t tnucks. Of the 2,713 vehicles counted duning the eight houn peniod,
I an additional 74 bicycles wene obsenved -- 2.7 pencent of the vehicle
count.
I
xMn. Richand Cutlen and Mn. Lynn Dudley, Colonado Division of
I Highways, Pianning and Reseanch Division, Tnafl"ic Investigations
I Section. This tnaffic sunvey was conducted by Jody Bishop and
Gina Bengenon, the John Ryan Company
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Exhi bi t I'lo. E-l
Traffic l4overnent Data
Matterhorn Entrance on Sou'rh Frontclge Road
Autonlobi.l es and Trucks
Vail, Colorado
lil --i6pe ri-iptr i-q iiqrsutt*--- f Tire-gl-E,Y
-9 - tu - 1t
- 1?
-t -2
-J
-+
Tota I
Notc: Nuntbcrs
8
l0
12
'I
2
.)
tt I
145 .l34
12?
.l48
157
'I 15
_9t
L, C93
877 17 83 26 92 27 1?B
32 163 24 147 38 127
?q- 150
200 957
9
1A
1 /'!
'I 1
ll
42
L6
53
24
JI
32
34
l-9_
263
9
lo
l6
t5
l0
12
94
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F.
t--
c
inside circles rcflect tYPe of traffic movcments
Lrl J (J
E.
(J
-z
d.
l:
Source: Iighl-hour
B a.n. to
traffic cotlnt, FriCay Atlgust 12' 1977 '
4 p.m.
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Exhibit l'lo. E-2
Cal cul at'i on Sheet
For Sumnrary Figures
Mattet ltlrn Circle and South Frontage Road
Vai1, Colorado
Type of tTtrrrr.r Cnrrr-,t
-L'i:!ii.,
. . -, - ._ :-'- .-,:.:-.
@ e67
fo\ 94
|,u5u E,,#
t/
N
FRONTAGE ROAD
ul J cl E
z
o I
[rJ
F.F
E
/a 6
I,058
@r,olr f @t#/
1 ,167
I no?
\ @ r,oe3 \€ r,fff
96
200
Note: Numbers inside circles reflect type of traffic movements.
Source: Eight-hour traffic count, Fri day, August 12, 1977, B a.m. to 4 p.m.
_37_
Cd
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for
Matterhorn
Exhibit iio. E-3
Calculation Sheet
Average Daily Traffic
Circle and South Frontage Road
Vail, Colorado
Secti on
n-f1
B-B
c-c
Tota I
8-Hou r
Count
I,058 + l,lBg
2,247
I,.|67 + 'l,356
2,523
296 + 357
ocJ
24-Hour
Fac tor llus.]
2
/.
2
Time
of Year
Factor
Road Type ADT
E st i nate
3,l gl
? r.Q?
966
Base
ADT
4,494
5,04e
I ,306
.71
(Group No. )
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967
Source: Eight-hour traffic count, Friday, August 12, 1977,8 a.rn. to 4 p.m.
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FROr.rrl.Gt_
5
(J
z ct o :E o:
H
F-g
'l ,058 I,.l67
I,l89 .l,093
AM
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Exhi bi t llo. E-4
Traffic Movernent Data
lrlatterhorn Entrance on South Frontage Road
Mo torcYcl es
Vai I , Colorado
Time of Day
Tvoe of Traff ic l4overnent
lf tu '1 t u -1
8
t0 I
12
I
-9 - t0 - lt
-12
-t -2
-L
0101 0l0l 0l0l 0103
0]03 0001 0.l03 q.o9_0.
_0- 0_ g 13
n
0
1
n
n
0,
t_
L
1 I
4
n
t_
:=Total
Note: Nutnbers
1--
t-.g
insidc circlcs reflect type of traffic movements
NTAGE ROAD/^\<----t
UJ J O
z
O l:&t!
Source: E ight- hour
B a.m. to
traffic count, Fricia,v, August 12, 1977,
4 p.m.
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Exhibit No. E-5
Traffic ltlovement Data
l.latterhorn Entrance on South Frontage Road
Bi cycl es
Vajl, Colorado
T'ime .of Day
Tvoe of Traffic Movement
Tr------Ti
00501 1032'l 00213 10223
00222 r0401 00324 00007
2021 sL
3
1
I
4
2
0
7
2
20
I
2
3
4
AM
9
t0
1t
12
Tota'l
Note: Numbers
F l-g
inside circles reflect type of traffic movements
OUTH FRONTAGE ROAD
ul J (.)
d.
()
z.E o _r
Source: Eight-hour I a.fl. to
traffic count, Friday, August 12, 1977,
4 p.m.
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Recorded
Rece Dtion
o'clock-- M.,
Recorder.
THts DBno, Made rhis 10th oay or Febrr.:ary
betwe€n $qr9 C4e9k Associates, A Rhode Isl_and LurrrEed .YarEnershiD
,le 8q
Colorado, of the second part,
WITN ESSETH ' That the said part! of the first part, for and in consideration of thesumof 00.00 00.00------ ______DoLLARS,
to the said par!r of the first part in h and paid by the !Bid part y of the s€cond part, the receipt whereof
is hereby confessed and acknowledged, ha remised, released, sold, conveyed and eUIT CLAIMED, and by these
presents dogg remise' release, sell, convey and QUIT CLAIM unto the said part y ofthe second part, iES heirs;
succ€ssors and assigns, forever, all the right, title, interest, claim and demand which the said part ofthe first psrt
ha s in and to the following described lot or parcel of land situate, lying and being in the county
nf Eagle and State ofColorado, to wit:
Glen Lyorr Subdivision :
Ttact J
Tlact A
Ttact C
Tfact B
Tfact G
TracE F
Ttact E
slso known as Btreet and number n/a
To HAVE AND To HoLD the same, together with all end singular th€ appurtenances and privilege! thereunto
belonging or in anywise thereunto appertaining, and all thc estate, right, title, interest and claim whatsoever, of the
said part) ofthe first part,eitherin laworequity, totheonly properuse, benefit and behoofofthe said part y of
t he second par t, sucget$EP,ff"""i gn" forever,
IN \rylrNEss wHEREOR The said part ofthe first part ha hereunto set igg hand
*Jtht , County of and state of
{flS9ta"'rtrL$Ffirst part, and the Tcrwn.of Vail, a t4-n'ricinal
colDoraEron
and state of
W*;b-w6
and geal the day and year first rbove written.a Rhode Island
Signed, Sealed and Delivered in the presence of
E. i(ates, Ceneral ParLner
smre or&g$t#*,*d
County of
The foregoing instrum€nt was ecknowledged before me this 22th day of February 1.,
whose legal address is 75 S. Frontage Rd. l{., Vail, Colorado
of the County of F:glg
88, uv'Henry E. I(ates, Ceneral Partr,er for nerEy b. KaEes, General_ partner for c;ore creek AssociaEes,
nv commissronrElm"* LttitSS ltew";gpitness my hand and orricial sear.
SEA LI
t sEALI
SEALI
SEALI
a Rhorh
No,933. eulr cL^ | ir rrEED.
-
AMEND}4ENT TO
PROTECTIVE COVENANTS
OF
GLEN LYON SUBDIVISION
This Arnendment to Protective Covenants of Glen Lyon
Subdivision is executed as of this day of , L987, by the
undersigned as the ovmers of at LeaT757.'of tffirface area of
the privately-onned land included within the boundaries of Glen
Lyon- ("Glen Lyon Subdivision") as set forth on the Amended Plat
for Glen Lyon-subdivision recorded July 18, L978 in Book 272 aE
Page 370 in the records of Eagle County, Cotorado.
RECITALS
AMENDMENT
For good and valuable consideration the owners hereby amend
the Declaration as follows:
1. Paragraph 1.4 is amended by the addition of a new
paragraph to read as follows:
"Pedescrian bridges, ski lifts, lift maze lines, ski
trails and related equipment and structures may be
constructed on TracE J, Tract H and the Stream Tract."
2. The second paragraph of Paragraph 1.4 is hereby amended
in its entirety to read as follows:
By Protective Covenants of Glen Lyon Subdivision
("Coveirants") recorded April 4, 1978 i; Book 268 at Page 598, of
the records of Eagle County, Colorado, Owner (as that term is
defined in the Covenants) imposed certain restrictions on certain
real property located in Eagle County, Colorado known as Glen
Lyon Subilivision. Pursuant to Paragraph 18 of the Covenants, the
Covenants may be amended by the wriiten consent of 757" of the
owners of the surface area of Glen Lvon Subdivision. The
undersigned represent at least 752 of such surface area and
desire to amend the Covenants as set forth below.
"Except for the structures which may be placed on Tract
J, Tract H-and the Stream Tract, no other sEructure, either
temporary or permanent, shall be erected, gonsEructed or
perfoitteii to iemain on the Subject Tracts."
-
3. This Amendment to Covenants may be executed in several
counterparts which when taken Eogether shall constitute a single
instrument and Ehis Aurendment shall become effective uPon the
recordaEion in the records of Eagle County, Colorado of
counterparts executed by the owners of at least 757" of t}:,e
surface area of Glen Lyon Subdivision.
Executed as of the date first above written.
LOT OR TRACT OWNER:
STATE OF
COUNTY OF
Subdivision sras acknowledged before me this
1987, by
ss.
The foregoing Amendment to ProtecEive Covenants
)
day
to Glen Lyon of,
, as Ehe
er dicaEed
!'Iitness my hand and official seal .
My cormission expires:
Notaiy Tublic
OWNER:LOT OR TRACT
STATE OF
COI]NTY OF
ss.
The foregoing Amendment
Subdivision was acknowledged
1987, by
Covenants to Glen LYon to Protective
before me this day of _,
yon '
CID L
dicated
above.
er(s ot or
Witness my hand and official seal .
My cormission expires: