|
UL
<br />DEPARTMENT OF NATURAL RESOURCES
<br />a
<br />t
<br />b �
<br />105 °i S'
<br />39'30 m
<br />PLATE -2
<br />Geo logit hazards are related to normal geologic processes.
<br />Hazards result frome the aa!M " interaction betwom the geologic!
<br />physi "611 coadittams ad m". The pm'poso of this hazard see*
<br />Is to identify problem Lrw, to provent the creation of now hazard
<br />areas or increasing time roo associated with existing areal, men!
<br />to assist plaonomrs to making rational lined -muse decisions. Mapping
<br />:emits used in this stt* eroily conform to the definitions pro-
<br />vided by Rogers, at lei. (1971). More informal ow on geologic
<br />`azard identification and mitigation procedures can be found in
<br />Ulne soma reference.
<br />Designation as a 'geologic hazard area' does n nece ssarily
<br />Haan that developmant can not take place or that high risks are
<br />lrplied. Identification only means that the prob ability exists
<br />that conditions in the aria could have am adverse impact on land -
<br />use. The mapping scale limits the size of identifiable hazard areas,
<br />some areas will contain small zoos of other hazards. More than one
<br />hazard commonly occur together, but for map clarity only the least pre.
<br />..71 "rat h :t:3rr? i - s .! slit.t t: .i. Tl".;'T, .. to m.•1,I i�, ` it * :x - '� 1
<br />project an a site - specific basis with full appreciation of the
<br />overlap and gradational nature between hazard areas. Every hazardous
<br />process should be reviewed during an investigation in any one geologic
<br />hazard area.
<br />This nap and legend were designed as reference meateriai for
<br />county planners and only as guides for mare detailed site- specific
<br />studies. These products represent generalized conditions over a
<br />broad zone and serve only to familiarize the site planner with the
<br />types and extent of hazardoas processes that he might encounter.
<br />Information provided in these products should not be used as the
<br />basis for engineering design but only as information that should
<br />e included i a review of proposed land -use changes.
<br />awl :•
<br />[E]
<br />5 1,1 :V 1 At /?lf BRIS -� aq
<br />0
<br />Fi ' , E_SQ1lJ ATT
<br />Lath 4jr'E ,.`r;A Areas wihere active sicpo failures can be
<br />identified. Evidence for shoe movement includes
<br />both geologic and physiographic features. A msocky
<br />terrain, steep scarps, disrupted vegetation, and de-
<br />ranged drainage patterns might be present. Slope
<br />aspect, gradient, ground Poisture conditions, and
<br />vegetation all affect landslide activity.
<br />Boundaries are generally distinct. Conditions
<br />leading to landsliding can occur outside the
<br />areas and are influenced by both natural processes
<br />and man. Risks resulting from landslides include
<br />damage to housing, utilities, and lines of commvni-
<br />cation.
<br />UNSTA6LE -SLGPE AREA Slope areas that have been failure zones in the
<br />recent geologic past, possibly under different clima-
<br />tic conditions. Evidence for present day activity
<br />is missing or uncertain. physiographic features are
<br />similar to those in l- andslide areas but more subdued.
<br />The same surficial processes and conditions that
<br />7US influence landsliding also influence unstable slope
<br />areas.
<br />Boundaries are generally easy to identify. These
<br />areas can be considered in 'metastable equilibrium'
<br />and any changes in present conditions, either natural
<br />or man - made, can reactivate failure activity.
<br />nT "cNTALLY- 4itSTAnLE Areas with all the sane geologic and physio-
<br />LG graphic characteristics of areas that have failed but
<br />that show no sign of past or present failure activity.
<br />Soil creep might be the only activity recognized'.
<br />Slope aspect and angle, composition, moisture condi-
<br />r + + ^ �+ �
<br />*ions, vegetation, etc. all influence the stability
<br />of these areas,
<br />1 p u are difficult to choose. Areas were
<br />outlined based on an understanding of the causes of
<br />mass wasting and instability. Risks are uncertain in
<br />:hcse areas, slight changes in cc^-Jitior,s could be
<br />catastrophic or cause only minor damage. The slope
<br />conditions give no indication of - what to expect.
<br />3^Cf`s1b "`A Areas where free - falling, rolling, sliding, or
<br />bounding rocks from cliffs, steep slopes, or overhangs
<br />can occur. Individual rockfalls occur very rapidly,
<br />are nearly unpredictable, and affect only limited
<br />areas per each event. Talus at the base of fractu! -od
<br />[ Rf or jointed bedrock cliffs is an indication of rockfa�i
<br />activity.
<br />The lower boundary on these areas is difficult
<br />to Dick. The rollout zone for rockfalls is a function
<br />of relief, slope shape and gradient, type of materials
<br />on slope, size and shape of blocks, and the presence
<br />of obstructions. The risks in these areas involve
<br />impact from the moving rocks to structures. Mitigaticr.
<br />procedures are usually expensive and not completely
<br />safe.
<br />Areas where futore flooding can be expected.
<br />Criteria used for identification Included tvi of
<br />Past floods, vegetation and drainage develop-
<br />meat. Climatic conditions, the ty" and frequency
<br />of storms and their intensity and duration, as well
<br />as geomorphic conditions influence the flood hazard.
<br />Soundaries are generalized, especially in areas
<br />*Glare the land surface has bean disturbed by constrvc-
<br />tion or agriculture. Risks associated with flooding
<br />Include inundation, sedimant deposition, chalmial
<br />erosion, and possibly shi fts in channel iositiona.
<br />All minor 4rall art potential areas for flash
<br />'foods. Individual mitigsti'on procedures are usually
<br />!ntffectlyt, flood- tontrol structures are more
<br />efficient.
<br />Areas subject to romal stream deposition and
<br />_`eposltion f9tam irfrequ -.rat debris /a:udflow events.
<br />raneraily a triangular shaped landform, lbcattd in
<br />porting fluid can't carry its sediment load. Areas
<br />were outlined based on their shape, position in
<br />drainages, and by the type of material present. Fan
<br />areas need a source of sediment, usually from high
<br />erosive sails, a drainage pathway. and the reduction
<br />in gradient an that pathway.
<br />lowndaries are distinct, with a small section of
<br />the contributing drainage included with each area.
<br />Risks involve frequent inundation, at the least minor
<br />,lopositional damage, and possibly major damage from
<br />the impact of moving debris. Some mitigation r.et. "gods
<br />can reduce the risks.
<br />Areas whitre surficial materials are s'uscepitble t-,
<br />erosion. Several variables affect erosion potential
<br />eluding: (1) soil type; (2) rainfall intensity &Md dura-
<br />tion; (3) infiltration rates; (4) length of slope:
<br />5) mngle of slope; and (6) surface r.•agh;ntss (vegetat'c -n,
<br />c nstructic,n, ate.). ^;xse areas ;vere s ".bdivlded into
<br />ly and low eMs s.
<br />High erosive soils were evaluated 4y tht ;resente of
<br />rills and gullies and by high K values (x.25), given to
<br />each soil type by the U.S. Soil Conservation Service
<br />(U.S.S.C.S.). Slope angle and vegetation ware also
<br />suo)ectivaly considered. Risks from these areas inclu=
<br />loss of topsoil, dissected terrain, and increased sedi-
<br />mint loads in streams.
<br />Low erosive -sails areas are either underlain by
<br />thin soils, by resistant materials, or are areas of de;osi -
<br />tion. Areas in floodplains can r"i .e sediment durinr,
<br />flooding. The flat - topped mesas usually are protected by
<br />erosion resistant gravels. Thin eolluvial soils over
<br />indurated bedrock show a low erosior. ct-ntial. Kiska
<br />ralat_ed to low erosive soils include excavation P"Jblers,
<br />drainage problems, high "water tables, and possibly
<br />flooding.
<br />Boundaries for erosive -soils areas are very - y eaeeral-
<br />ized, usually overlapping with swelling -soils ar^was.
<br />>tneralization is necessary because ernsicn is relates
<br />to how much man disturbs the envirorrent. Climate,
<br />topography, vegetation, and land -use are the Tajor con-
<br />trols on erosion hazards.
<br />Areas underlain by soils or soft bedrock which
<br />experience change in volume, either swelling or shrink-
<br />ing, with changes in moisture conditions. Certain clay
<br />T;inerals, like montmorillonite, are very susceptible to
<br />swelling and units composed primarily of this mintrai
<br />=an have very high swelling potentials. gypsum and
<br />other sulfates also experience volume charges and art
<br />considered in this hazard category. The amount and tare
<br />of mineral present in the soil, initial density, charges
<br />in moisture content, the load on the soil, and time all
<br />zffect 'the amount of possible swelling. Two subareas
<br />ire I dentified.
<br />High swell - potential areas were cncsen based cn
<br />'Inforr.ation from U,S.S.C.S. mapping, Bedrock units ha`
<br />are known to have swelling problems, and areas of ooc-
<br />:ern texture or deep desiccation crack;, ^g. r:reas w^er�
<br />- < e as :lue to v+^ellinq pressures -,-?re also inc':uee�.
<br />t s»tii is usually greater than percent. Severe
<br />aana "3e to all structures can result if these areas are
<br />not investigated.
<br />Low sweli- potential areas were outlined mainly from
<br />U.S-S.C.S. mapping and information in other sources.
<br />Percent swell is less than S percent. Risks include
<br />minor cracking of roads, sidewalks, plaster walls, and
<br />possibly misfit of doors and windows.
<br />Boundaries for swelling soils areas are vary
<br />general and should not be considered precise. Swelling
<br />soils and erosive soils commonly exist together, with
<br />slope conditions and vegetation controlling which hazard
<br />Is more severe. Identification and proper oena+ggineet'ing
<br />"esign unually can minimize the risks in swe111mg »soi1P
<br />areas.
<br />E
<br />RD
<br />SMELL'' -SOILS AREAS
<br />Sh
<br />J� If
<br />38'22"30•
<br />105'15 Rf
<br />ac ,
<br />'' op
<br />OP o o' Sass from U.S. Geological Survey, 1959.
<br />'OP
<br />+ "e Phaterevised, 1916.
<br />REFERENCg3
<br />Latmpiris, N., Unpubl. maps, Geologic hazards
<br />and natural resources of Frenront County,
<br />Colorado: available from County Land -
<br />Use Board, Canon City, Colo.
<br />'lagers, at al., 1974, Guidelines and
<br />criteria for identification and land -
<br />use controls of geologic - hazard and
<br />mineral resource areas: Colo. :eol.
<br />NM
<br />f
<br />LL VLI vV
<br />Im m m =mon o Mine Permit Boundary
<br />N
<br />o lobo. 2000 x.000 n
<br />SCALE: T' 20 -�
<br />GEOLOGIC-HAZARD a• OF H E t
<br />CANON CITY' QU
<br />by Bruce W. Beach
<br />SCALE 12A000
<br />1000 a 1000 2000 low +000 5000 6000 7000 FEET
<br />5 0 1 K1lOWTE,
<br />CONTOUI N ERVAL 20 FEET
<br />Of I WAM
<br />111
<br />Numerous small alluvial /debris fan areas
<br />LJ occur at the base of most slopes.
<br />l�l Corrosive soils.
<br />�} Flood hazard difficult to evaivate
<br />because of dale andJor housing
<br />--� construction.
<br />sr* and subsidence 'TaZar3 -way e%i 3 t
<br />1
<br />'oath of this li x.
<br />CANON CM QUADRANGLE �;u -
<br />C.OLORADO- FREMONT Go
<br />S MINUTE SERIES (TOPOGRAPHIC)
<br />i 105'0730'
<br />[' IRS. 7lCC -! .:.�•. '4t 7 38*30
<br />r F
<br />,
<br />XAZAM AAEAS
<br />Potenttatly
<br />Unstable -Slope Unstoble -Slit Alluvial Erosive Saails Swelling Soils
<br />Landslide Area Area Area Rackfall Area Flood Area Debris -Fan Area High Erosion Area Low Erosio Area High Swell Art A rta
<br />Selective siting
<br />of buildi++g CAA
<br />reduce risk.
<br />i
<br />Trrination canals increase risk.
<br />OFH
<br />3
<br />A8C0F
<br />3 A4C DE F
<br />3 g F
<br />3A8EFGH
<br />2 8 C 0 E F ra H
<br />IF ,CE
<br />3 OEH
<br />2 0 p
<br />ASCUF
<br />litigation is
<br />Careful siting
<br />Design and site
<br />Mitigotiow case
<br />fiery few slopes
<br />Extensive work
<br />Good drainage
<br />Excavation might
<br />Proper design
<br />Proper can aaad
<br />iir
<br />expensive. Main-
<br />and engineering
<br />investigations
<br />be expensive.
<br />(<3%) leave peer
<br />and mitigation
<br />design will
<br />be expensive &M
<br />construction can
<br />maintenance cam
<br />.ensity
<br />tenance costs
<br />can reduce risk.
<br />can reduce risk.
<br />Mirror problem:
<br />irainage.
<br />can reduce risk.
<br />reduce risk.
<br />difficult.
<br />redwA risk.
<br />rsdice risk.
<br />1
<br />high.
<br />0 18
<br />C H E F G'
<br />1 1 DE H n n s �►
<br />-wei
<br />w probie . l'uiiying
<br />and loss¢i'ew
<br />protleim. ILIgnt
<br />)
<br />of t ^p50i 1 - ,an '
<br />3� cas i,,nal tit
<br />oeial
<br />-
<br />3
<br />A8 CD f'
<br />2
<br />A8CDFH
<br />2
<br />aCDf
<br />3
<br />A8t0EF
<br />8 u
<br />A$E FG:k
<br />ev l
<br />eloip oc�erst
<br />3
<br />2
<br />5C0E FGft
<br />f
<br />9CEF
<br />3 s3 EH
<br />2 DEH
<br />Low
<br />Good engineering
<br />Remedial con-
<br />Site iovestiga-
<br />Selective
<br />:"ery low slopes
<br />Cost! nits ati
<br />Y 9
<br />Good drain age
<br />May be subject
<br />P roper design
<br />Proper care &Ad
<br />tensi y
<br />can hel redact
<br />p
<br />st ti d
<br />rucon an
<br />bons required.
<br />s iting can re-
<br />f<3t) have poor
<br />necessary.
<br />desi;n can reduce
<br />to flooding near
<br />and fewn tructien
<br />maintenance sae
<br />risk.
<br />engineering may
<br />duce risk.
<br />'Drainage.
<br />risk.
<br />flood areas.
<br />can reduce risk.
<br />reduce risk.
<br />be necessary.
<br />31
<br />A 6 C D E F H
<br />3 JA
<br />a C D F H
<br />2 A 3 C O F
<br />3 1
<br />A 8 C D E r
<br />4.
<br />D E F 5
<br />2 A 9 E t G H
<br />18 F
<br />1
<br />C O E d
<br />1 I C E F it
<br />2 f DEN
<br />1 D f li
<br />Costs increase
<br />Proper design
<br />Good pIamIaq
<br />Engineering and
<br />Good drainage
<br />High maintenance
<br />Drainage design
<br />Subject to floods
<br />High maintenance
<br />Minor damiagle
<br />Roads
<br />for design and
<br />and maintenance
<br />can reduce risk
<br />design can reduce
<br />structures can
<br />costs.
<br />and maintenance
<br />if located near
<br />costs.
<br />,
<br />road cracking.
<br />construction.
<br />can reduce risk.
<br />risk.
<br />reduce risk.
<br />can reduce risk,
<br />flood area.
<br />2 A8CDEF
<br />!A$CDFH
<br />1
<br />A5 C0Fit
<br />2 f A 1C0E F
<br />1 I t
<br />I ABEFGH
<br />2
<br />EC1) EFG H
<br />0EFH
<br />2
<br />10 EH
<br />1
<br />OtN
<br />Occasional
<br />Engineering and
<br />Good planning
<br />Careful sItiwa
<br />Looks in water
<br />igh maintenance
<br />High maintenance
<br />May be difficult
<br />Good design
<br />Few problems.
<br />Utilities
<br />damage. Good
<br />design can reduce
<br />can reduce risk.
<br />can reduce risk.
<br />fiats can In-
<br />sts.
<br />costs.
<br />and expensive to
<br />rekRecas risk
<br />design can reduce risk. create risk.
<br />risk.
<br />I A 8 E H I I A 8 F - 0 — FA - 8 F IT _ A5 E t
<br />Open Span
<br />Recreation
<br />Minor problems.
<br />No problem.
<br />No problems.
<br />Selective siting
<br />of buildi++g CAA
<br />reduce risk.
<br />Mlmor problems.
<br />Trrination canals increase risk.
<br />one steeperground
<br />tin affected by
<br />Ind lance 1 iota
<br />i tiH
<br />0 H
<br />3A8CDEF
<br />3A3C0F
<br />2
<br />ASCUF
<br />2
<br />AtCDEF
<br />2' 9EF
<br />Industrial
<br />Mitigation is
<br />Engineering and
<br />Maintenance
<br />Main
<br />High alatatetmanco
<br />and
<br />;. nercial
<br />Development
<br />expensive but may
<br />make project
<br />passible.
<br />design should be
<br />required.
<br />and good design
<br />can reduce risk.
<br />cost may be hi
<br />Costs. Desig"
<br />can reduce risk.
<br />i i A80EFH l A0DFH
<br />fl A8DF
<br />1 I As Df l0 T A M
<br />Airnor preble . 1rri4at10n can
<br />miawrr trouble
<br />1.214 a areas cage
<br />Trrination canals increase risk.
<br />one steeperground
<br />tin affected by
<br />Ind lance 1 iota
<br />i tiH
<br />0 H
<br />stgrae of Risk
<br />H! git 3
<br />icderata
<br />2
<br />re tt e f "" is _ "a • ` -e d" st Division of Minerals and Geolog:
<br />iflu ha -.ard% :r#iditi *nil f .ri � 4i €r%ca ha = ar� rd ds���
<br />a, local relief can affect hazard. 'star; can vary sons
<br />3. --d9 rem of slope (angle) air "ects �emavimq vegetation can increase
<br />' hazard. - ask.
<br />v. Nerstaecirlo or 1 "aditua �x'+nsiry 3ftd ^iuvnlnfnfwt ..t
<br />MAP 6
<br />GEOLOGIC- HAZARDS MAP
<br />I Northfield Mine Project
<br />Northfield Partners, LLC
<br />P.O. Box 260678
<br />Littleton. CO 80163 -0679
<br />:n zOVP
<br />oe.r.�ea o +, a,nz
<br />excavate.
<br />ASE6H
<br />1
<br />BE6H
<br />0
<br />19 F6M
<br />i tiH
<br />0 H
<br />sk must be
<br />aluated for
<br />tential losses.
<br />Recreational uses
<br />can be affected
<br />by rill and gaily
<br />Off -read use by
<br />vehicles can
<br />increase risk.
<br />Light -wetot
<br />structures can
<br />be dangerous.
<br />No problem.
<br />erosion.
<br />A B E F G H
<br />2 19 C O E F G H
<br />0 18 C F H
<br />21
<br />D E H
<br />0
<br />D E H
<br />gh maintenance
<br />sts.
<br />Drainage design
<br />and maintenance
<br />Few problems.
<br />Good ergimwriP
<br />and design can
<br />Mirror problem:
<br />can reduce risk.
<br />reduce risk.
<br />S E F G H
<br />1
<br />B C tl E F G H
<br />0 18
<br />C H E F G'
<br />1 1 DE H n n s �►
<br />-wei
<br />w probie . l'uiiying
<br />and loss¢i'ew
<br />protleim. ILIgnt
<br />)
<br />of t ^p50i 1 - ,an '
<br />3� cas i,,nal tit
<br />DEPAR'1'MF.,NT OF NA7'U12�
<br />re tt e f "" is _ "a • ` -e d" st Division of Minerals and Geolog:
<br />iflu ha -.ard% :r#iditi *nil f .ri � 4i €r%ca ha = ar� rd ds���
<br />a, local relief can affect hazard. 'star; can vary sons
<br />3. --d9 rem of slope (angle) air "ects �emavimq vegetation can increase
<br />' hazard. - ask.
<br />v. Nerstaecirlo or 1 "aditua �x'+nsiry 3ftd ^iuvnlnfnfwt ..t
<br />MAP 6
<br />GEOLOGIC- HAZARDS MAP
<br />I Northfield Mine Project
<br />Northfield Partners, LLC
<br />P.O. Box 260678
<br />Littleton. CO 80163 -0679
<br />:n zOVP
<br />oe.r.�ea o +, a,nz
<br />
|