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Home My WebLink About1.05 Preliminary planst PRELIMINARY PLAN FOR THE MAHAN SUBDIVISION BEING THE w1/2 SW1/4 NE1/4 OF SECTION 9, TOWNSHIP 7 SOUTH RANGE 89 WEST OF THE 6TH P.M., GARFIELD COUNTY, COLORADO BLM FOUND REBAR & CAR -- NW CORNER OF THE 5W1/4 NE1/4 OF SECTION 9 210 •"' POINT ' 1- L. BLM OF BEGINNING LOT 1 UND REBA & CkP #12083 1 ,/ /. L=127.9 R-101. L=7' C Denis Hines 0897 County Road 126 Glenwood Springs, CO 81601 D' 100' 0 U1 CO Sharon Stephenson 0430 County Road 126 Glenwood Springs, CO 81601 Fri L= R= CL BRG- 24 K 483 ASEMENT AT 'AGE 421 5 BUIL RAGE 1G CABIN STORAGE & TANK �- NTERLIN K 483 0' UT1LIT T PAGE 4 EASEM NT L= ' 7.93' R 122.27' =50'34'3 C EN - BR WATER TANK PRING BOX AVIS WELL LINES (TYP 7' WA R Iv 4NTEN AS ESCRI L= R= 0= C L BRG A CE EASE D 300' E MIMI NM MINIMMB SCALE -1 INCH = 100 FEET Kathleen S. Harris 0987 County Road 126 Glenwood Springs, CO 81601 tO /L 24' ROAD EASEMENT_ BOOK 535 AT PAGE 602 ( POINT OF BEGINNING LIT 2 FOUND REBAR & ALUMINUM CAP CENTER 1/4 CORNER OF SEC. 9 BLN 8 0 c'0 SURVEYO'S CERTIFICATE I, DON A. BAGENT, DO HEREBY CERTIFY THAT I AM A REGISTERED LAND SURVEYOR LICENSED UNDER THE LAWS OF THE STATE OF COLORADO, THAT THIS PLAT IS A TRUE, CORRECT AND COMPLETE PLAT OF THE MAHAN PROPERTIES, SUBDIVISION EXEMPTION PLAT AS LAID OUT, PLATTED, DEDICATED AND SHOWN HEREON, THAT SUCH PLAT WAS MADE FROM AN ACCURATE SURVEY OF SAID PROPERTY BY ME AND UNDER MY DIRECT SUPERVISION AND CORRECTLY SHOWS THE LOCATION AND DIMENSIONS OF THE LOTS, EASEMENTS AND STREETS OF SAID SUBDIVISION AS THE SAME ARE STAKED UPON THE GROUND IN COMPLIANCE WITH APPLICABLE REGULATIONS GOVERNING THE SUBDIVISION OF LAND. IN WITNESS WHEREOF, I HAVE SET MY HAND AND SEAL THIS DAY OF , A.D., 2005. 8,, • DON A. BAGENT REGISTERED LAND SURVEYOR P.L.S. #26950, FOR AND ON " BEHALF OF SCARROW & WALKER, INC. ;31. 269 - Ci'' W 65 '.97 \ 1 FOUND REBAR & ALUM. CAP L.S. #16842 Kenneth Green 65 Favre Lane El Jebel, CO 81623 24' ROAD EASEMENT BOOK 483 AT PAGE 421 Richard & Jennifer Chavez 4703 County Road 117 Glenwood Springs, CO 81601 NOTES 1) BASIS OF BEARINGS FOR THIS SURVEY IS A BEARING OF N.01'02'01"W. BETWEEN THE CENTER 1/4 CORNER OF SECTION 9, AND THE NORTHWEST CORNER OF THE SW1/4 NE1/4 OF SECTION 9 AS SHOWN HEREON. 2) DATE OF SURVEY: JANUARY, 2004. 3) THIS MAP WAS PREPARED WITHOUT BENEFIT OF A CURRENT TITLE COMMITMENT AND DOES NOT REPRESENT A TITLE SEARCH BY THIS SURVEYOR OR SCARROW & WALKER, INC. OF THE PROPERTY SHOWN TO DETERMINE OWNERSHIP, COMPATIBILITY WITH ADJOINING PARCELS, CR EASEMENTS OR ENCUMBRANCES OF RECORD AFFECTING THIS PARCEL. ALL SUCH INFORMATION SHOWN HEREON ARE ACCORDING TO (SCHEDULE B -SECTION 2 --EXCEPTIONS) OF A TITLE COMMITMENT ISSUED BY STEWART TITLE OF GLENWOOD SPRINGS ORDER NO. 13613-G, SAID COMMITMENT WAS FURNISHED BY THE CLIENT. 4) EASEMENT AND RIGHT OF WAY FOR POWER LINE EASEMENT AS SAME CROSSES THE NORTHEASTERLY PORTION OF SUBJECT, ACCORDING TO ABOVE TITLE COMMITMENT. 5) TOPOGRAPHIC INFORMATION SHOWN IS FROM U.S.G.S. QUADRANGLE MAP. BOUNDARY DESCRIPTION W1 /2 SW1/4 NE1/4 OF SECTION 9, TOWNSHIP 7 SOUTH, RANGE 89 WEST OF THE SIXTH PRINCIPAL MERIDIAN, GARFIELD COUNTY, COLORADO. PROPERTY DESCRIPTION LOT #1 A PARCEL OF LAND SlTUA1ED IN THE W1/2 SW1/4 NE1/4 OF SECTION 9, TOWNSHIP 7 SOUTH, RANGE 89 WEST OF THE SIXTH PRINCIPAL MERIDIAN, GARFIELD COUNTY, COLORADO; SAID PARCEL BEINU MORE PARTICULARLY DESCRIBED AS FOLLOWS: BEGINNING AT A POINT ON THE NORTHERLY LINE OF THE SW1/4 NE1/4 OF SAID SECTION 9; WHENCE THE CENTER 1/4 CORNER OF SAID SECTION 9, BEING A REBAR AND ALUMINUM CAP PROPERLY MARKED, BEARS S.24'39'51 "W, 1513.29 FEET; THENCE 5.00'53'29"E. 757.36 FEET, TO A POINT ON THE CENTERLINE OF AN EXISTING ROAD EASEMENT AS RECORDED IN BOOK 477 AT PAGE 372 OF THE GARFIELD COUNTY CLERK AND RECORDERS OFFICE; THENCE ALONG SAID CENTERLINE THE FOLLOWING; NINE (9) COURSES; 1) 79.55 FEET ALONG A CJRVE TO THE RIGHT HAVING A RADIUS OF 109.69 FEET, A CENTRAL ANGLE OF 072'18" (CHORD BEARS N.83'57'34"W. 77.82 FEET); 2) N,64'32'22"W. 113.78 FEET; 3) 107.93 FEET ALONG A CURVE TO THE RIGHT HAVING A RADIUS OF 122.27 FEET, A CENTRAL ANGLE OF 50'3439" (CHORD BEARS N 44'09'29"W. 104.46 FEET); 4) N.29'20'24"W. 101,86 FIET; 5) 124.41 FEET ALONG A CURVE TO THE LEFT HAVING A RADIUS OF 989.34 FEET, A CENTRAL ANGLE OF 07'1218" (CHORD BEARS N.38'04'27"W. 124.33 FEET); 6) 118.70 FEET ALONG A CURVE TO THE RIGHT HAVING A RADIUS OF 88.06 FEET, A CENTRAL ANGLE OF 77'13'45" (CHORD BEARS N.11'58159"W. 109.92 FEET); 7) N.18°41'21"E. 154.37 FET; 8) 127.96 FEET ALONG A CURVE TO THE LEFT HAVING A RADIUS OF 101.60 FEET, A CENTRAL ANGLE OF 72'0938" (CHORD BEARS N,14°00'07"W. 119.67 FEET); 9) N.46'45'08"W. 103.62 FEET, TO A POINT ON THE NORTHERLY LINE OF SAID SW1/4 NE1/4; THENCE LEAVING SAID CENTERLINE AND ALONG SAID NORTHERLY LINE S.89°46'05"E. 445.47 FEET TO THE POINT OF BEGINNING. SAID PARCEL CONTAINING 5.66 ACRES, MORE OR LESS. PFOPERTY DESCRIPTION LOT #2 A PARCEL OF LAND SITUATED IN THE W1/2 SW1/4 NE1/4 OF SECTION 9, TOWNSHIP 7 SOUTH, RANGE 89 WEST OF THE SIXTH PRINCIPAL MERIDIAN, GARFIELD COUNTY, COLORADO; SAID PARCEL BEING MORE PARTICULARLY DESCRIBED AS FOLLOWS: BEGINNING AT THE CENTE! 1/4 CORNER OF SAID SECTION 9, BEING A REBAR AND ALUMINUM CAP PROPERLY MARKED; THENCE N.01'02'01"W. ALONG THE NORTH SOUTH CENTERLINE OF SAID SECTION 9, 1378.11 FEET TO THE NORTHWEST CORNER OF THE SW1/4 NE1/4 OF SAID SECTION 9; THENCE S.89'46'05"E. ALONG THE NORTHERLY LINE OF;AID SW1/4 NE1/4, TO A POINT ON THE CENTERLINE OF AN EXISTING ROAD EASEMENT AS RECORDED IN BOOK 477 AT PAGE 372 OF THE GARFIELD COUNTY CLERK AND RECORDERS OFFICE; THENCE ALONG SAID CENTERLINE THE EOLLOWItG NINE (9) COURSES; 1) S.46'45'08"E. 103.62 FET; 2) 127.96 FEET ALONG ACURVE TO THE RIGHT HAVING A RADIUS OF 101.60 FEET, A CENTRAL ANGLE OF 72'0938" (CHORD BEARS S.14'00'07"E. 119.67 FEET); 3) S.18°41'21 "W. 154.37 FET; 4) 118.70 FEET ALONG A2URVE TO THE LEFT HAVING A RADIUS OF 88.06 FEET, A CENTRAL ANGLE OF 77'1345" (CHORD BEARS S.11'58'59"E. 109.92 FEET); 5) 124,41 FEET ALONG A-URVE TO THE RIGHT HAVING A RADIUS OF 989.34 FEET, A CENTRAL ANGLE OF 07'1218" (CHORD BEARS S.38°04'27"E. 124.33 FEET); 6) S.29'20'24"E. 101.86 FET; 7) 107.93 FEET ALONG ACURVE TO THE LEFT HAVING A RADIUS OF 122.27 FEET, A CENTRAL ANGLE OF 50'339" (CHORD BEARS S.44'09'29"E. 104.46 FEET); 8) S.64'32'22"E. 113.78 =ET; 9) 79.55 FEET ALONG A',URVE TO THE LEFT HAVING A RADIUS OF 109.69 FEET, A CENTRAL ANGLE OF 07'1218" (CHORD BEARS S.83'57'34"E. 77.83 FEET, TO A POINT ON THE EAST LINCOF SAID W1/2 SW1/4 NE1/4 OF SECTION 9; THENCE LEAVING SAID CENTERLINE AND ALONG SAID EAST LINE S.00'53'29"E. 621.51 FEET TO THE SOUTHWESI'CORNER OF SAID W1/2 SW1/4 NE1/4 OF SECTION 9; THENCE N.89'39'06"W. AiNG THE EAST WEST CENTERLINE OF SAID SECTION 9 652.97 FEET TO THE POff OF BEGINNfNG. SAID PARCEL CONTAINING 15.06 ACRES, MORE OR LESS. 20 FOOT WTYR LINE AND MAINTENANCE EASEMENT A 20 FOOT STRIP OF LAI`[ FOR THE PURPOSE OF AN EXISTING WATER LINE AND MAINTENANCE EASEMENT, )CATED IN THE W1/2SW1/4NE1/4 OF SECTION 9, TOWNSHIP 7 SOUTH, RAN( 89 WEST OF THE SIXTH PRINCIPAL MERIDIAN, GARFIELD COUNTY, COLOR)°, THE CENTERLINE OF SAID EASEMENT BEING MORE PARTICULARLY DESCIBED AS FOLLOWS; BEGINNING AT AN EXISTIN WELL WHENCE THE CENTER 1/4 CORNER OF SAID SECTION 9 BEING A REBA AND ALUMINUM CAP PROPERLY MARKED, BEARS S.23'16'13"W. 504.17 FEE -THENCE N.64'21'15"E. 59.92 FEET; THENCE N.09'55'11"W. 46.47 FEET;THENCE N.31'25'53"E. 140.52 FEET; THENCE N.57'34'021. 71.81 FEET; HENCE N.45'43'04"E. 37.21 FEET TO A POINT IN THE CENTERLINE OF A 6000T EASEMENT AS DESCRIBED IN BOOK 577 AT PAGE 372 IN THE RECORDS CF -lE GARFIELD COUNTY CLERK AND RECORDERS V CI\ITY MAP SCAB I\ CH = 2000 FEET PLAT NOTES 1. Control of noxious weeds is the responsibilit/ of the property owners 2. line (1) Hog will be allowed for each residen-lal unit and the dog shall be required to be con -Fined within the owners property boundarie_, 3. No open hearth solid -fuel fireplaces wilt be allowed anywhere within an exemption. One C1) new solid -fuel burning stove as defined by CRS'. 25-7-401, et seq , and the regulations promulgated there under, will be allowed in any dwelling unit. All dwelling units will be allowed an unrestricted number of natural gas burninc stoves and appliances, 4. All exterior lionting shall be the minimum amoant necessary and that all exterior lighting be directed inward and downward, towards the intrior of lots subdivision, except that provisions may be made to allow for safety lighting that goes beyond the property boundaries 5. Colorado is a "Right -to -Farm" State pursuant to CRS. 35-3-101, et seq Landowners, residents and visitors must be prepared to accept the activities, sights, sounds and smells of Garfield County's agricultural operations as a normal and necessary aspect of living in a County with a strong rural character and a healthy 'arching sector, Those with an urban sensitivity may perceive such activities, sights, sounds and smells only as inconvenience, eyesore, noise and odor. However, State law and County policy privide that ranching, farming or other agricultural activlties and operations within Garfield Count shall not be considered to be nuisances so long as operated in conformance with the law and r a non --negligent manner. therefore, all must be prepared to encounter noise, odor, lights, mu., dust, smoke chemicals, machinery or public roads, livestock on public, storage and disposal of r>_nure, and the application by spraying or otherwise of chemical fertilizers, soil amendments, herbirdes, and pesticides, and one or more of which may naturally occur as a part of a legal and nor -negligent agricultural operations, 6. All owners of land, whether ranch or resic nce. have obligations under State law and County regulations with regard to the maintenance o fences and irrigation ditches, ccn ironing weeds keeping livestock and pets under control, using property in accordance with zoning, and other aspects of using and maintaining property. Re idents and landowners are encouraged to learn about these rights and responsibilities and a t as good neighbors and citizens of the county. A good introductory source of such Information is "A Guide to Rural Living & Small Scale Agriculture" put out by the Colorado State lniversity Extension Office in Garfie'sd County, LAND USE BREAKDOWN EXISTING )NING - TOTAL DE'_OPMENT AREA - TOTAL NI3ER OF LOTS PROPOSED - TOTAL Nl3ER OF DWELLING UNITS PROPOSED - TOTAL NIBER OF NON-RESIDENTIAL FLOOR SPACE - TOTAL NIBER OF INDIVIDUAL DWELLING UNITS PROPOSEFOR EACH STRUCTURE TOTAL NI3ER OF OFF STREET PARKING SPACES TOTAL PFOSED DENSITY A -R -RD 20,72 ACRES TWO TWO N.A. ONE N.A. 20.72 ACRES ENI EE CHS HALE - MOUNTAIN CROSS E 821/2 GRAND AVENUE GUW009 SPINGS, COLORADO (g) 945-5544 \I D NEEDING EXEMPTION CER TI FIGATE THIS PLAT APPROVED BY RESOLUTION C THE BOARD OF COUNTY COMMISSIONERS AT GARFIELD COUNTY, COLORADO THIS DAY OF A.D. 2005. IN FILING WITH THE CLERK AND ECORDER OF GARFIELD COUNTY, SUCH APPROVAL IN NO WAY IMPLIES THAT TH- INFORMATION SHOWN HEREIN IS TRUE AND ACCURATE BUT DOES INDICATE THAT TPS PLAT IS EXEMPT FROM AND NOT SUBJECT TO REGULATION L'NDER GARFIELD COUNT SUBDIVISION REGULATIONS AT THE TIME OF ITS FILING. CHAIRMAN WITNESS MY HAND AND SEAL OF THE RUNTY OF GARFIELD. ;TTEST: COUNTY CLERK COUNTY SU'VEYOR'S CERT FICATE APPROVED FOR CONTENT AT FORM ONLY AND NOT THE ACCURACY OF SURVEYS, CALCULATIONS OR DRAF,NG. PURSUANT TO C.R.S. 1973, 38-51-101 AND 102 (REVISED). BY: GAF1ELD COUNTY SURVEYOR GTE: CLERK AND RE- ORDER'S CERTIFICATE THIS PLAT WAS FILED FOR RECORD IN OFFICE OF THE CLERK AND RECORDER OF GARFIELD COUNTY AT O'CLOCK __ _M., ON THE DAY OF , A.D. 205, AND IS DULY RECORDED IN BOOK , PAGE , RECEPTION NO. CLERK<ND RECORDER BY:, EPUTY NOTICE: ACOORDU TO COLORADO LAW, YOU MUST COMMENCE ANY LEGAL ACTION BASED UPON ANY DEFECT IN THIS `.RVEY WITHIN THREE (3) YEARS AFTER YOU DISCOVER SUCH DEFECT, IN NO EVENT MAY ANY ACTIONIASEC UPON ANY DEFECT IN THIS SURVEY BE COMMENCED MORE THAN TEN (10) YEARS FROMHE DATE OF CERTIFICATION SHOWN HEREON. SCARRO W & WALKER INCORPORATED Registered Land Surveyors 818 Colorado Avenue Glenwood Springs, Colorado 81601 (970) 945-8664 a> E G escriotion of revisions date ci C . . job number : 08.1/7 drawing number : 03117 coord file number : 031/7 era' dls drawn by: O p PREPARED FOR. JAMES & ROBERTA MAHAN 1fiIRAN- PROPERTYES 0648 County Rd 126 Glenwood Springs, CO 8160> (970) ,945-031.9 (OWNERS / APPLICANTS) MouNTr��N cRoss \ � El�1GINEERING, INC. December 07, 2005 Mr. Fred Jarman Garfield County Planning 108 8t1 Street, Suite 201 Glenwood Springs, CO 81601 CIVIL AND [NVIRONMENTAL CONSULTING AND DESIGN RE: Technically Incomplete Response to Preliminary Plan for Mahan Subdivision Dear Fred: Attached are two (2) copies of the following items, submitted in response to your letter dated June 10, 2005, concerning the determination of the Preliminary Plan submittal for the Mahan Subdivision being "Technically Incomplete": 1. Preliminary Plan map title has been corrected. 2. Preliminary Plan map has departing property lines included. 3. Report prepared by HP Geotech has been included. 4. Figure 3 and supporting pages from the SCS Soil Survey show the project location and the corresponding soils types. These pages are intended to be an amendment to the previously submitted drainage report. 5. Figure 4 and supporting pages from the SCS Soil Survey show the project location and the corresponding plant associations and major tree masses. These pages are intended to be an amendment to the previously submitted drainage report. Please continue to review the application in light of the additional information attached. Feel free to call if any of the above needs clarification or if you have any questions or comments. Sincerely, Mountai r, Cross Eng ering, Inc. i ris Hale, PE C: Mrs. Roberta Mahan Attachments REC DEC 0 3 2005 826 1/2 Grand Avenue • Glenwood Springs, CO 81601 PH: 970.945.5544 * FAX: 970.945.5558 • www.mountaincross-eng.com 06/22/05 SOLE MORE Chris Hale IWO rri Dradwtan A. 501-OQE FIGURE 3 SCS Soils Mahan Subdivision MOUNTAIN CROSS ENGINEERING, INC. Civil and Environmental Consulting and Design 826 1/2 Grand Avenue Glenwood Springs, CO 81601 ph 970.945.5544 fx 970.945.5558 www.mountaIntross.eng.com a,I osieetos SCALE 1' • 300' IMMO Chris Fiats oro iU DrwbnPton 501-001 FIGURE 4 Vegetation Mahan Subdivision MOUNTAIN CROSS ENGINEERING, INC. Civil and Environmental Consulting and Design 826 112 Grand Avenue Glenwood Springs, CO 81601 ph 970.945.5544 fx 970.945,5558 wwvw.mountaincross-eng.com �:. Unite::: States Departrnent o44 AcrIc.i urs Soy Soriserva Ior Seov;cc ,r coo, v,i'tr Unced States Departnen' c4 the InteYlo'. Bureau C' _aric f1ar;agenen a c tr,e ,o;oradc Agr,c.:c 'a 7i..?Jerfrr&fn Station Soil Survey of Aspen -Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties s.. ..I.?,;:„._.__i...._:_...<---------:;:..:4 Aeber-uvw'sarr Area �oioracc ;imy loan-;. 12 to 25 percent slopes. Tnis dee la ainec s., is tars arc adianias i tori ec s. 'derived cOrlirantis _r- Dara eonsrec.-iced - ato and sna'c Eiev"atio'r is C 0C is .80C feet aieraoe a=nr.Ua Oreclpitaticr 7 2 to Inones ting µ,-,-ace ann a al" temberatar_ ;a 42 to 48 aegrees arc a Jerage frost -free period is 85 to 105 says '-yoicaliy the surface Jaye" is raadisn brown cern arcs 6 incites tnick Tne uppe' 2 inches of the sJosol is ;: ire sandy icaFr The lower 15, inches is sa.nav clay iOa" Tele sJostraturi to a ceptr of SC friaries or mOre sal lay cam The sol is ncinnalcareous, to a beau- o' ep'.io' •rdnes and oaicareous vie:OA Inat deotr. aG u Ir tris unit are sinal. areas of Empeareoc and s..oris ma: are similar to the Aim;, sal' but are ca:;afeous witnir a eectr a' IC incr'es Included areas make ..p aoout 20 percent of Ire tota' acreage. ce-nneaollity is moderate it the Aimy Avaiiabia water capacity is mar. The effective rooting aepti. is 60 inches or more Runoff is medium.. aria tlnl.e nazarc of wale' erosion is moderate. Tnis unit is used as rangeland Tne potential. p'iant community is mainly. bluebuncn wheatgrass. Indian ricegrass. bott'ieorush squirreitalii Douglas rabbitbrusr. ane '4yaming bid sagebrush. Prairie junegrass. needieandthread. and Sandberg bluegrass also are included The average annual pr;ocluctior of air-dry vegetation is about 950 pounds per acre. If the range .dor=aitrer deteriorates.. Wyoming big sagebrush. Douglas raboitorus'n cneatgrass. and.annuaweeds increase in abundance.. Range seeding may be needed if the range is in poor condition. The suitability of this unit for range seeding is leo Tee ma'n limitation is the slope Brusn management improves deteriorated areas O` tango that are producing more woody shrubs than were present in . the potentia plant community 4r areas where brush is rerriovea by prescribed burning or by Crtemical or rnecrrianicai metnods. the hazard of erosion may increase if tris unit is used for homesite aeveiopment tne -.Mair limitation is the slope This map unit•is in capaoliity suaciass Vie. nonirrigated. It is it the Rolling Loam ranee site. 8—Ansel-Anvik association, 12 to 25 percent slopes. This map unit is or fans foot siopes and n-iountalnsides. Elevation is 7,500 to 9.500 feet. The aysrage annual precipitation is 18 to 22 inches tine average anriva air temperature is 35 me 40 degrees F. and ire average frost -free period is 70 to 80 gays This unr is aoout 7C percent Anse sol' and 20 p`'rcerr: Anvii< sol' Tne Anse sol` is or fans arc foot S.Ocie's and ire Artivrk so€': is or fans and rriountainsir s �rii, are ar._ .a eas o S'1C.In, arc C,o7T1,c. aco�. V C scent o' Ire Iota acreage Tne Anse so; is deep arc J='e; ana.ried It formed in aliuviJet ae ivec oomrriantry hcrn In-iateria of mixed mineralogy Typicaliv toe s irtaCe. I:aye' iigrr'. Drown sr dray loan- aoout 22 inches thick Tne upae` 25 inches of the s,osoi is stony clay ioa`` Trie owe par tt a ceatr a' SC mores is cay loam Permeaollity is moderately slow ii the .Arise SO1. Avaliaoie water capacity is nigr. Tire effective rooting Deign is OC 'nolle_ o- more flu: -oft fhe nazarc o' water erosion Is macerate Toe Anvil, sal is Cees and wet crannied i:- Torn;ec ir a,1.J`Jlurr anc colluvium derived COm na.'r'i - from materna of mixed mirieraiogy_ i ypicaily tree surface 'aye is grayish orowr loam aoout 12 'ncnes hick.. Tne subsurface layer leant gray loan- aoout £ merles thick. Tne subsoil is cobbiy clay loam about 24 inches thick Tne substratum to a ceptr: of 6C inches is co.bbiy clay loam. Permeaoillty is moderate in the Anvik sol:- Available water capacity also is moderate The effective rooting depth 60 inches or. more Runoff is medium. and the hazard of water erosion is moderate This unit is used as` woodland (fig. 3: or as wildlife ,habitat. it is well suited to the production of .Gougias fir. Based on a site inaex of.91 it. can proauoa about 8.70C cubic feet. or 52.200 board feet iinternationa'l rule). of merchantable timber per acre trod` a fully stocked stand of even -ages trees 1'00 years old Tnis unit is poorly suited to htimeslte development. The main limitations are the Slope and tne hazard o' slumping in areas where excavations Or road cuts are mace. This map unit is in capability subclass vie. nonirrigated11 is it the Spruce -Fir woodiand site. 9—Ansel-Anvfk association, 25 to 45 percent slopes. This map unit is oh fans. foot siopes. and mountainsides Elevator is 7.500 to 9.500 feet The average annuali precipitator is IE to 22 incnes the average annual air.. temperature is 35 mg 40 degrees F. and Inc average frost -free period is 70 to 80 days. This unit is about 70 percent Anse soil arc 2C percent Anvik sol`. Tne Anse` soil is on tans and toot slopes. and the Anvik soil is or fans and mountainsides inc uaed in this unit are srn.al areas of Skyiick.. Sligtind. ant Gothic soilsincivaec areas €mice uC about IC percent of tne mama acreage Tee Arise sol: is deep arc wel. drained i" formed in ali+uviurr derived dominantly: fro': materia' of mixed mineralogy Typically file surface iaye' Is rant orownisr gray loan-. aoout. 2° 'ncn es t^4c Trie upper 25- inches 20 Soil Survey Figure 3.—A wooded area of Ansel-Anvik association. 12 to 25 percent slopes. of the subsoil is stony clay loam. The lower part to a depth of 60 inches is clay loam, Permeability is moderately slow in the Ansel soil. Available water capacity is high. The effective rooting depth is 60 inches or more Runoff is rapid, and the nazard of water erosion is moderate Or severe on the steeper slopes The Anvik soli is deep and well drained_ it formed in alluvium and coliuvium derived dominantly from material of mixed mineraiogy. Typicaiiy the surface 'ayes �s grayish DrotNn loam about 12 inches thick. The subsurface iayer=. light.t gray ioarn about 6 inches thick. The subsoil is cobbiy clay loam about 24 inches thick. The substratum, to a depth of 60 inches is cobbly clay loam Permeability is moderate in the Anvik soli. Availabie water capacity aISC is moderate The effective rooting neotb is 60 inches or more Runoff is rabid. and the Hazard of water erosion.. moderate or severe or the steeper slopes Thi unit i5 •SBO as woodland c as wildlife n.abi.a . is suited to the product=or Douglas fir eased on a site index of 85. it can produce about 7.700 cubic feet. or 46.200 board feet (international rule). of merchantable timber per acre from a fully stocked stand of even -aged trees 100 years old. The main concern in producing and harvesting timber is the slope Applying conventional harvest methods is difficult because of mis iimiltation. This units poorly suited to nomesite development. The main limitations are the slope and the nazard of siumpinc ;n: areas where excavations or road cuts are made. This map unit IS in capability subclass Vlle. nonirndated it is in the Spruce -Fir woodland site. 10—Anvik-Skylick-Sligting association. 10 to 25 percent slopes. This map unit is on fang and mountainsides Elevation is. 7.500 to 9.500 feet The average annual precipitation is 1i8 to 22 'Hones me average annual air temperature is 38 to 40 degrees T and the average frost -free period is 70 to 80 days. This unit is about 30 percent Anvik. soi 30 percent Skylick so?I. anis 30 Percent Siioting soil 50 Soil S;rvey;: s 18 to 20 incriec.. .re averaoe ann; a air temperature re is 37 to 3`9 degrees F. and the average 'ost- re& oec00 s 50 to 70 days. Typically. the surface layer s light orownisr pray silty clay loam about 6 monies thick. The nex: ,ayes is clay about 9 inches thick. The substratums clay about 18 inches thick over shale. The depth to calcareous snaie ranges from 20 to 40 inches. The soil is caicareous throughout. Included in this unit are small areas of Forsey. Cochetopa. Antrobus. Anvik, Skyiick, and Sliating soils. Included areas make up about 15 .percent of,the total acreage. Permeability is sidw in the iyers soil, Available water capacity is low. The effective Footing depth is 20 to 40 inches. Runoff is rapid. and the'hazard of water erosion is moderate to severe on the steeper slopes. + This unit is used as:rangeland,; watershed. or wildlife' habitat. The potentia{ plant community is mainly Thurber fescue. Idaho fescue'. and neediegrasses. Other plants that characterize this ste are slender wheatgrass.. nodding brome; and silver sagebrush. The average annual production of air-dry vegetation, is about 2.500 pounds per .acre If -the range condition deteriorates. silver sagebrush and Kentucky bluegrass increase in abundance, This unit is..poorly suited to homesite development. Theimain lirnitations are the shrink -swell potential anal the slope. This man unit is in capability subclass Vile. nonirrigated. It is in the Subalpine Loam range site. 63—Jerry loam, 12 to 25 percent slopes. This deep. well drained soil is on alluvial fans and hills- It formed in alluvium derived dominantly from sandstone and snaie. Elevation Is 7.500 to 9.500 feet. Tne average annual precipitation is 1,8 to 20 inches the average annual air temperature is 37 to 40 degrees F. and the average frost -free period is 70 to 80 days Typically the surface Sayer is dark grayisr: brown cam aboutinches thick. The subsoil is chancery clay loam about 23 :cones thick. The suostrat .arc to a depth 0` 50 Inches Is very chancery clay loam inciubed .n this unit are small areas of Showalter Morvai. Cochetopa. Trideli anc Fugues soils Inciuded areas make up about 15 percent of the total acreage. Permeability is moderate In the Jerry soil. Avaiia'oie water capacity also is mooerate The effective rooting depth is 60 inches or more Runoff is rapid and the nazard of water erosion is moderate This unit is user as rangeianc Tne potential plant community .s mainly mountain brome. elk sedge mountain sn.owberry Gambel oak. arc Saskatoon: sery°:ceoerry Other plants that orcaracterize this sire are slender wheatgrass o ceed!eOrassesan:d western wneatgr ass : he average an.nua' prOCucticri vegetation .s about 2.000 pounds ocr acre. If the 'anger:. condition deteriorates rabbitbrush. Kentucky bluegrass'; Canada thistle. arc downy bromegrass increase abundance This unit is poorly suited to homesite developrnment The main limitations are the shrink -swell potentia: and the slope. This map unit is in capability subclass we.. nonirrigated. It is in the Brushy Loam range si.te 64—Jerry loam, .25 to 65 percent slopes. This deep,_ well drained soil is on ailuviai.fans and hills. It fo;,medri alluvium derived dominantly from sandstone aria shale. Elevation is 7.500 to' 9'500 feet. The average annual precipitation is.'18 to 20 inches, 'the average annual air' temperature is37 to 40 degrees F. and the average' :. frost -free period is 70 to 80 days. • Typically, the surface layer. Is dark grayish brown loam about 11 inches thick. The subsoil is chancery clay loam about 23 ihches thick. The substratum to depth of 60 inches is very chaihnery clay Ilam. Included•in this unit are small areas of Showalter, ... Morval. Cochetopa,' Tridell, and Fughes 'soils..I.ncluded . areas make up about 15 percent of the total acreage;i:, Permeability is moderate in the Jerry soil. A�ai!able;` water capacity'also is moderate. The effective rooting.; depth. is 60 inches or more. 'Runoff is very rapid. the hazard of water erosion is moderate. This unit is used as rangeland.. The potential plant community is mainly mountain brome. 'elk sedge. mountain snowberry, Gambel oak. and Saskatoon serviceberry. Other plants that characterize this site are slender wheatgrass. needleorass. and western wheatgrass. The average annual production of air-dry' vegetation is about 2.000 pounds per acre. If the ,ani condition deteriorates. rabbitbrush. Kentucky bluegrass. Canada thistle, and downy bromegrass increase ,n abundance. This unit :s poorly suited to ,omesitc development: The math limitations are the shrink -swell cote tial and the slope. This mac unit is in capability subclass Vile nonirrigated. it is in the Brushy Loam range sfTe 65—Jerry-Milleriake loan's. 1 to 6 percent slopes This map unit is on alluvial fans and valley side s}ore' Elevation is 7.500 to 9,500 feet. The average annuali. orecioitatior is 18 to 20 inonies the average an"'.Jai a' temperature ,s 37 to 40 degrees F and we average frost -free period is 75 tc 85 dais. This unit ,s about OC percent . erry sGi' and 41: percent Milieriake SOii 160 Soil Survey 6.--2i:.GS:A`5 ,N: WOODLAND JN.._:`S.:C_Z's so__s t.._ __--_arc w od:and _17--s_str _ . _t_... s__-.aclefer_ az- - are - Sc:_ na,.,e and Range or woodland sate map symbol -Kind of year Cry we'ig:nt Lb/acre Ci-.araoneristic ve _____..n 2 Lcany Slopes #3'.;.3-;- Favorable _,200 .:ae ooun_a_r,mahcgany .5 Acree ;Ncrrr.a". 900 -Antelope __:er'nruso 15 Unfavorable 530. Western, wneatgrass---- :0 e nea:ass 'Sa_satoo setv;ceberry s B1'.1e-botc:n u.n,eatgrass .n.dian cegrass— N,o',:n,ta:n c g `sage ' 3, 4, 5 !Mountain Lowe #225 _av0rable 1,800 ;Slender•wneatgrass Acree Nc:mal 500 ;Nodding bromegrass ;0nfavcrable' ;000 iNestern wheatrass fLettermar. neadlegrass- I iNcunta"_n big'sage dabo fescue ' ', Saskatoon.'servlceberry 6, 7 ;P.ollin:g Loam #298 Favorable , I '_,LOC.'S'luebuncb wheat -grass :5 Almy I !Normal 950 :Needleandthrea..; 10 t , 'Cnfavcrable 650 -Sandberg bluegrass 10 0 -[ :0 • _0 .0 • 8r, 9*: Ansel Spruce-_i- Nyom'_ng big sagebrush 10 IBottlebruen sguirreltail 5 :ndian __cegrass 5° !Favorable 300 Sedge :5 Normal 25C 'Slender wheatg-ass 15 !Unfavorable 175 1Boxleaf myrtle 10 Dwarf blueberry :0 eartleaf arnica 10 Anvik Spruce-__- !Favorable Norma: ;Unfavorable 107, s, Anvik Aspen 300 Elk sedge 15 250 ',Slender wheatarass 15 75 Sexieaf myrtle Dwarf bluetoerry ..ear_lea_ arnica No .,_o..,egrass- Favc_ao_e 3,5:0 ___Ge_ fescue Norm,: -5_ry ,,.._avc_an_e - 2,0 _cane fescue Nod.dLng z__.^.'ec ass uu,.: _cnarass Se=_ded wheangrass SAV_ _ck Amen evo aD__ 3,:-,C0 Thurber __s.....----- Norm.a_ 3,300 a__y zangrass ...".favorable :0 Idano _esc.:e Bea_c_c «n.ea as_ Alpe-- Normal See f.,, _octe a_ er.n Nodding c_cm.ev_ass M'.: _tong_ ass 0 _`e so _,e C Ncc..Lng ororn g_a_s :0 :0 10 _0 5 5 :0 0 '0 3 1.0 166 So0 S:,; -e -BL_ _.--?<: :x =\. 2NC=RS70;R _R:;. ,-- - Soil name a..^.c Range or woodland s_=e Cnaraccerisc_c vegelarion :raw sym:ool y.= -.-of gear we gcc 62, 64 ecry :Brscy Lca.r, #2:8 , 66', .terry iSrusny Loam f2 rr,l acre r _. Favorable3,C,C0 ,iarr.ze_ oak :r Kora_ 2,0.0,C Elk sedge • 0c ravcra^v_e 1,300 -!3oun e c scowcerry Mc _a_.. w_cce Saskatoon -servicebe__y :letterman neen_egrass . avcrar_e Norm.al Un'avorab_e' ,;G'.. Ser.be_ 2,0-0C Elk setae 1,500N:d n e snowbe__y Sas:iatcor..seroeberrs ----- Le==ermar. r.aealecrass M ier.-aKe Sony a'7. 0.23-7 Favorable 2,000 31:aec.:c.c'. wnea_grass Norma: 1,200 .Saskatcor serv_ceberr_i-- _ :5 - c_avc_an_e. COO Mo, _air :c sate 10 Tcanc 'esc°3e ' :0 Needegress _...._L.. __cgcrass a ,ccelcpe bi.__erbr•.:si: 68 -Mountain 5•waCe #245 Favorable 3,000 `Bash. w::drye 20- Jodero ;Norr,a: . 2,500 Nesters whea=grass 15 :U^`_avarab_e 2,006 3as:- ..:a sagebrush _5 •Noun=air. arome :0 65----------------- irour:ta'_r. Meecuw #240 Kilgore 72 Koc a _ Kcibar ,wee-^, __ay Loam_ Lex _avc_ac_e 4,000 •Tufted ,:a_ crass Norma: 3,000 Sedge ,Un`_avcrab:e 2,000 Cinque`_ci_ _cvcc No_c-a_ Unfavorable SOalnlne _..,a.. 0350 See f•osino:e a: end Df Favcradle •.3as_n wild -ye Rush ---------- - ZS 30 10 10 2,10C .'Aes=ern whoa grase 30 60C Letterman neer- ass_ 18 Letterman:,400 Wyoming n - sager -as_ la Vii'.:==..ngro I - ,20: KC 14cna_ , 3__r'.eg__.ss 5 Sas a_ccr. ser,ceber V.,__sea_ wye:..__------------- i "ries-..__.. w.._ _. 'cOg sage ----I M..__ .Ss Small _es„_---------- -i -0 - 'esti_--------- --------k • his �E rO w.cea� ass ---- >5,- ..__-j.._a 5 {"Flooding" and less than; estimated} TABLE 16. --SOIL AND WATER FEATURES "water table" and terms such as "rare,- "brief," and "apparent" are explained in the text. The symbol < means > means more than- Absence of an entry indicates that the feature is not a concern or that data were not Flooding I High water table Bedrock Risk of corrosion Soil name and Hydro- I map symbol E logic I Frequency { Duratiorr [Months Depth group f I- I I I i I Potential I I Kind Months IDepihlHard- I frost 'Uncoated ICnncrete I I 1 ness 1 action 1 steel I i Et I 1, 2 C (None I >6.0 Acree ' I. I 1 3, 4, 5 C 'None >6.0 Acree 1 1 6, 7 0 INone >6.0 Almy A*, 9*_ I .I Ansel R [None- --- >6.0 I Anvik B (None -e --- I >6:0 I 10*, 11*: I I Anvik B (None --- I >6.0 1 Skylick N !None I >6.0 f ,' Sligting C INone [. >6.0 17*: l Arlo-- C [None >6,0 Ansari B (None - l >6.0 Rock outcrop. I I I 1 I I 1.1*: I I I I Atencio- -----I A 'None I I >6.0 I I E I A7.eltine---- I B (None' i >6.0 1 14*: I I - I Callings---- I C [None ' I.>6.0 I Yeljack I R INone. I "y- I >6.0 1 15*, 16*: I I I I Charcol. I B INone I --- I >6.0 1 Hard -----I C INone --- i >6.0 I See footnote at end of table. I In I I I 1 I >60 [Low [High ILow. 1 1 1 I I I - I >60 --- ILow 'High !Moderate. I I I I h I I >60 [Low [High [Low. 1 I I I I I 1 I >60 'Moderate ---'Moderate ILow. 1 1 1 I. >60 IModerat.e---I Moderate ILow. I I I i •>60 IModerate---IModerate ILow. 1 I >60 [Moderate ---[Moderate ILow- ' I >60 --- IModerate---IMndecate 'Moderate. I I I I I I I 1 20-40 soft ILow [High [Low. I I I I I --- 10-20 Hard ILow--------[High ILow. I I I I I I E I I i I I I I I I I --- >60 I - ILow----------'High ILow. I I 1 >60 I [Low (High ILow. I I I I I I I I --- >60 I [Moderate ---!Moderate ILow- ' 1 I E >60 I !Moderate---IModetate 1T.,ow. I I I I I I 1 >60 ---Moderate [Moderate_ l I I 1 >60 I IModerate---[Moderate [Low. I I I f opeiolo3 `BeN wnsdiC0-uedSV TABLE 16 ---SOIL AND WATER FEATURES --Continued Flooding I High water table I Bedrock I I Risk of corrosion Soil name and I Hydro- I I I I I I I I { Potential I I map symbol I logic I Frequency I' Duration (Months I Depth,( Kind (Months IDepthlHard- frost (Uncoated (Concrete group I - I.' �I I I I I I ness l action I steel I --- I I 42* I l Ft I I I In ! I I 1 1 D !Occasional - Brief Mar -Sep 10.6-2.0IApparent lMar-Sep t >60 Fluvaguents I i • I. 43*, 44*: I f Forelle I R (None 1 Brownstn- I 45, 46, 97 I R INone Forsey I 1 • 1 48 I C INone Fughes I I 1 49, 50 I B INone Goslin I I ! 1 51, 52, 53 I C [None Gothic I 54 I 13 INone Grotte 55*: Gypsum land. I 1 Gypsiorthida 56, 57---- 7pson I I 1 58 .---- I C INone Irrawaddy I 1 D INone--- ( H INone 59, 60, 61, 62----I C Tyers 64 Jerry 65*, 66*, 67x: Jerry Millerlake 68 ,lode r o L INone 1 C !None 1 R I Narie I R INone 1 See footnote at end of table_ >6.0 I >6.0 I --- I >6.0 I I ! >6.0 I I ! >6.0 I I I I >6.0 >6.0 >60 >60 >60 >60 >60 >60 >60 >6.0 10-40 Soft I I i >6..0 --- >60 I --- 1 I ! >6.0 ---- 20-40 Hard 1 I I I E 1 >6.0 20-40 Soft I { I I I I [ >6.0 I I >60 1 --- >6.0 I .! >60 --- I . >6.0 I I >60 I --- I I V >6.0 --- I ! >60 I 1 1 High IHigh------ILow. I I I I Low !High (LOW_ 1 Low (High €Low. 1 Moderate ---(High }Moderate. 1 1 Moderate ----(Moderate 1 ILow_ 1 1 Low 1 1 ModerateIHigh (Low. I 1 1 Low---- 1High------Low_ 1 I I 1 1 1 Low !High IHigh_ 1 Moderate---IHigh !Moderate. I i 1 Moderate ---(High Mow. ! I I i Moderate ---(Moderate 1 1 Moderate ---!High (Low_ I I 1 I 1 Moderate ---(High ILow- 1 Moderate---IHigh ILow- I 1 Moderate---IHighIT,ow. I I 1 opeioloo `saiv wnsao-uedsy DEC -06-2005 13:46 H—F-ECrTECH GLgaStech HEPWORTH - PAWLAK GEOTECHNICAL 1-icpworth-Pawlaic l3eotc•c;^.sr >:1, Inc. 5020 County Ro:xd 154 Glenwood Springs, Coln:r.:i .l60I Phone: 970-945-7988 Fax 970-915.8454 email: hpgeofohmeoreeh,corl PRELIMINARY GEOTECHNICAL ENGINEERING STUDY PROPOSED MAHAN SUBDIVISION BLACK DIAMOND MINE ROAD (COUNTY ROAD 126) GARFIELD COUNTY, COLORADO JOB NO. 105 897 DECEMBER 5, 2005 PREPARED FOR: JAMES AND ROBERTA MAHAN P.U. BOX 3574 SOUTH PADRE ISLAND, TEXAS 78597 BUILDING f'L Parker 303-841,7119 • Colorado Springs 719-633-5562 * Silverihorne 970-468.1989 P.02/21 DEC -06-2005 13:46 H-- 'iEOTECH P.03/21 TABLE OF CONTENTS PURPOSE AND SCOPE OF STUDY - I - PROPOSED DEVELOPMENT -1 - SITE CONDITIONS GEOLOGIC SETTING - 2 - SITE GEOLOGY -3 - FIELD EXPLORATION - 4 - SUBSURFACE CONDITIONS - -5 - GEOLOGIC SITE ASSESSMENT -5 - PRELIMINARY DESIGN RECOMMENDATIONS - 7 - FOUNDATIONS -7 FLOOR SLABS - 8 - UNDERDRAIN SYSTEM - 8 - SITE GRADING - 9 - SURFACE DRAINAGE - 9 - LIMITATIONS - 9 - REFERENCES - Ii - FIGURE 1- LOCATION OF EXPLORATORY BORINGS FIGITRE 2- LOGS OF EXPLORATORY BORINGS FIGURE 3- LEGEND AND NOTES FIGURES 4 through 6- SWELL -CONSOLIDATION TEST RESULTS TABLE 1 -SUMMARY OF LABORATORY TEST RESULTS DEC -06-20055 13;46 H aEDTECH PURPOSE AND SCOPE OF STUDY This report presents the results of a preliminary geotechnical study for the proposed Mahan Subdivision to be located off Black Diamond Mine Road (County Road. 126) in Garfield County, Colorado. The project site is shown on Figure 1. The purpose of the study was to evaluate the geologic and subsurface conditions and their impact on the project. The study was conducted in accordance with our proposal for geotechnical engineering services to James and Robert. Mahan, dated August 22, 2005. •A field exploration program consisting of a geologic reconnaissance and exploratory borings was conducted to obtain information on the site and subsurface conditions. Samples of the subsoils obtained during the field exploration were tested in the laboratory to determine their classification, compressibility or swell and other engineering characteristics. The results of the field exploration and laboratory testing were analyzed to develop recommendations for project planning and preliminary design. This report summarizes the data obtained during this study and presents our conclusions and recommendations based on the proposed development and subsurface conditions encountered. PROPOSED DEVELOPMENT The proposed development will consist of a two lot subdivision as shown on Figure 1. Lot 1, treated to the east of Black Diamond Mine Road will be 5.66 acres in size and Lot 2 to the west of the road will be 15.06 acres in size. The development will consist of single family homes. Private driveways will access the building sites_ We asstu.nle the residences will be typical of the area and be two stories of wood frame construction over a crawlspace or with a basement level. The development will he serviced with individual wells and septic disposal systems. if development plans change significantly from those described, we should be notified to re-evaluate the recommendations presented in this report. Job No. 105 597 tr.cf-‘ P.04/21 DEC -06-2005 13 46 H- EOTECH -2- SITE CONDITIONS P.e5/21 The proposed subdivision consists of 20.72 acres that will be divided into two lots. There is an existing art studio/office and residence on Lot 1. and a cabin, storage building and framed dugout on Lot 1. The terrain on the property is variable with strong to moderately steep slopes down to the east at grades up to about 16%, There was about 3 to 4 inches of snow cover at the time of our field exploration. Vegetation consists of scattered evergreen trees, scruboak, grass and weeds. GEOLOGIC SETTING The project area is located on the southeast limb of the Grand Hogback Monocline roughly 31/2 miles south of Glenwood Springs. The Grand Hogback monoeline is a first order structure that defines the boundary between the Carbondale evaporite collapse center to the east of the project site and the Piceance Basin to the west, The Piceance Basin is a structural feature formed between the White River uplift and the t ! ncompahg re uplift, during the Laramide orogeny about 40 to 70 million years ago (Kirkham and others, 2002). The Carbondale evaporite collapse center is a roughly circular region with a diameter of about 20 miles that has subsided as much as 4,000 feet within the last 10 million years (Kirkham and Others, 2002). There is no definitive evidence of deformation during post - glacial times, about the past 15,000 years within the collapse center (Widmann and Others, 1998) and no potential impacts of the collapse center on the project site are expected. Landslide deposits are mapped in the project area and vary in age from currently active to as old as early Pleistocene (Kirkham and Others, 1996). Landslide complexes have developed throughout the area as a result of deformation in the Grand Hogback monocline and stream erosion that produced the modern topography throughout about the last 14 million years_ Types of landslides in the project arca include rotation:l.landslides, translational landslides, complex slump earth flows and extensive slope-fhii.11re complexes. Jobb No. W5 897 cagbach DEC-06-2ee5 13:47 H- lEOTECH The project area is underlain by the Cretaceous -age Mancos Shale Formation- The Mancos Shale consists of light to. dark gray, carbonaceous shale with thin beds of bentonite, siltstone, and sandstone. The bedding in the Mancos Shale strikes northwest and dips at about 55° down to the southwest beneath the project area. Previous geologic mapping in the area shows a system of northwest trending, bedding plane, flexural slip faults projected through the project area. These faults arc the result of structural lowering of the Grand Flogback along the margins of. the Carbondale cvaporite collapse center during the Late Cenozoic, within about the last 10 million years, and are - not considered capable of generating large earthquakes (Kirkham and Others, 2002). Geologically young faults not associated with evaporite tectonics and considered capable of generating large earthquakes are relatively distant from the proposed development site (Widmann and Others, 1998). The closest faults with known or suspected movement during the Late Pleistocene, within about the last 130,000 years, are located in the Rio Grande rift about 50 to 70 miles to the east of the project site and include the north and south sections of the Sawatch fault zone, the Frontal fault, the Mosquito fault and the Williams Fork Mountain fault. The northwest -trending, Late Pleistocene Cini.aron fault located near the boundary of the Gutmison and Uncompahgre uplifts is located about 60 miles to the southwest of the project site. SITE GEOLOGY STREAM CHANNEL ALLUVIUM Stream channel alluvium in the project area is mostly confined to ephemeral drainages. These alluvial deposits locally consist of poorly to well sorted, stratified, interbedded pebbly sand, sandy silt and sandy gravel. Clasts consist of subr untied basalt and Mancos Shale derived cobbles and boulders. Job No. 105 897 P.O6/21 DEC -06-2005 13:47 H—r 'EOTECH -4- COLLUVIUM P.07/21 Colluvium found on hillsides throughout the northern part of the project area ranges from clast-supported, pebble to boulder size fragments in a sandy clay matrix to matrix - supported gravelly, clayey, sandy silt. Clasts are typically angular to subangular and consist mainly of Mancos Shale derived cobbles and boulders. LANDSLIDE DEPOSITS The hillside in the project area is dominated by a large, hill slope -failure complex. This landslide is a geologic feature that probably developed during the late Pleistocene, within about the last 60,000 years. The landslide deposits in the project area consist of unsorted, ungratified clay, silt, sand, gravel and rock debris. Clasts are derived from the Mancos Shale Formation in the project area as well'as from basalt gravels deposited upslope to the north and west of the project site. Judging from surface observations in the field, it appears that most of the hill slope -failure complex has been dormant for a relatively Iong time and the potential for major landslide reactivation in the project area appears to be low. FIELD EXPLORATION The field exploration for the project was conducted on November 16, 2005. Two exploratory borings were drilled at the Iocations shown on. Figure 1 to evaluate the subsurface conditions. The borings were advanced with 4 inch diameter continuous flight auger powered by a truck -mounted CME -45B drill rig. The borings were logged by a representative of Hepworth-Pawlak Geotechnical, Inc. Samples of the subsoils were taken with a 2 inch T.D. spoon sampler. The witpler was driven into the subsoils at various depths with blows from a 140 pound hammer falling 30 inches. This test is similar to the standard penetration test described by ASTM.Method D-1586. The penetration resistance values are an indication of the relative density or consistency of the subsoils. Depths at which the samples were taken and the penetration Job No. 105 897 Gtech DEC -06-2005 13:47 H -P ':1OTECH resistance values are shown on the Logs of Exploratory Borings, Figure 2. The samples were returned to our laboratory for review by the project engineer and testin .. SUBSURFACE CONDITIONS Graphic logs of the subsurface conditions encountered at the site are showy on Figure 2. The subsoils consist of about % to 1 foot of topsoil overlying stiff to very stiff. sandy clay with scattered gravel increasing with depth. Relatively dense, clayey sandy gravel containing basalt fragments up to boulder size and clay layers was encountered beneath the day at depths of 8 and 9 feet. Drilling in the basalt rock materials withauger equipment was difficult due to the size and hardness of the rock and clrfUinl; refusal was encountered in the deposit in Boring 1. Laboratory testing performed on samples obtained from the borings included natural moisture content, density and liner than sand size gradation analyses. Results of swell consolidation testing performed on relatively undisturbed drive samples of the clay soils, presented on figures 4 through 6, generally indicate low compressibility under existing moisture conditions and light loading and low to moderate expansion potential when wetted under a constant light surcharge with swelling pressures up to about. 8,000 psf. The laboratory testing is summarized in Table 1. No free water was encountered in the borings at the time of drilling or when checked 1 day later and the subsoils were moist. GEOLOGIC SITE ASSESSMENT The proposed development area is not i npacted by rockfall or snow avalanche hazards. Conditions of a geologic nature that should be considered in project planning and design are landslides, construction induced slope instability, expansive soils, and earthquakes. Job No. 05 897 Gtech P.08/21 DEC -06-2005 13:48 H—r -EOTECH -b- LANDSLIDES Previous mapping shows that the proposed development area is located on .landslide deposits. No ground cracks or other evidence of recent pound movements were observed during our field reconnaissance. Based on our field observations and regional .studies, it is reasonable to infer that the likelihood of large scale landslide reactivation during a reasonable service life for the residence is low. Although the probability of landslide reactivation is low, the property cannot be considered risk free. The prospecl:ivc homeowner should be aware of this risk. If this risk is unacceptable to the prospective homeowner, it should be possible to design the foundation for small scale hillside creep movements, A structural engineer familiar with foundations designed to resist differential ground movements should be consulted to review possible mitigation options. CONSTRUCTION -INDUCED SLOPE INSTABILITY We do not expect any major problems with construction induced slope instability at the project site for goading typically associated with residential construction on slopes less than 40%. However, deep cuts into the deposits at the project site could have a risk of construction -induced slope instability if grading for the proposed structure is not engineered properly. Slope stability issues are discussed further in the Site Grading section of this report. EXPANSIVE SOILS Laboratory testing of samples acquired during our field exploration indicate that the natural soils on the property are expansive in some areas, Expansive soils, when dry, provide acceptable support, but under conditions of post -construction wetting, they can undergo relatively large differential heaving. When the proposed building locations have been determined, a site specific geotechnical study should be conducted to evaluate the expansion potential of the natural soils at the building sites and develop criteria. for foundation designs. Expansive soil conditions are discussed further in the Preliminary Design Recommendations Foundation section of this report, Jab No. i 05 897 P.09/21 DEC -06-2085 13:48 H -F -OTECH P.10/21 7 EARTHQUAKE CONSIDERATIONS The project area could experience earthquake related ground shaking. IIistoric earthquake ground shaking in the region has been moderately strong, but has not exceeded Modified Mercalli Intensity VI (Kirkham and Rogers, 1985). Modified Mercalli Intensity VI ground shaking should be expected during a reasonable exposure time for the proposed development, but the probability for stronger ground shaking is low., Intensity VI ground shaking is felt by most people and causes general alarm, but results in negligible damage to stnictures of good design and construction. structures should be designed to withstand moderately strong grournd shaking with little or no damage and not to collapse under stronger ground shaking. The U.S. Geological Survey National Seismic Hazard Map indicates that a peak ground acceleration of 0.06g has a 10% exceedence probability for a 50 year exposure time at the project site (Frankel and Others, 2002). This corresponds to a statistical recurrence time of 475 years. The region is in the 1997 Uniform Building Code, Seismic Risk Zone l . Based on our current understanding of the earthquake potential in this part of Colorado, we see no reason to increase the previously accepted seismic risk zone for the region. PRELIMINARY DESIGN RECOMMENDATIONS The conclusions and recommendations presented below are based on the proposed development, subsurface conditions encountered in the exploratory borings and our experience in the area. The recommendations are suitable for planning and preliminary design but a site specific study should be conducted for the design of each building. FOUNDATIONS Bearing conditions will vary depending on the specific location of the building on the property, Based on the nature of the proposed construction spread footings bearing on the natural subsoils should be suitable at the building sites. We expect the footings can be sized for an allowable bearing pressure in the range of 2,000 psf to 3,000 psf. Expansive Job N:,. 105 597 �h DEC -86-2885 13:48 H -P -OTECH S P.11/21 clays encountered in building areas may need to be removed or the footings designed to impose a minimum dead load pressure to limit potential heave. Boulders in the subsurface soils could be difficult to excavate and result in an irregular bearing surface. Foundation walls should he designed to span local anomalies and to resist lateral earth loadings when acting as retaining structures. Below grade areas and retaining walls should be protected from wetting and hydrostatic loading by use of an underdrain system. The footings should have a minimum depth of 36 inches for frost protection. FLOOR SLABS Slab -on -grade construction should be feasible for bearing on the natural. soils. There could be some post construction slab movement at sites with expansive clays. Subexcavating the clays and placing granular structural fill could be used to reduce the heave potential. To reduce the effects ofsome differential movement, floor, slabs should be separated from all bearing walls and columns with expansion, joints. Floe slab control joints should be used to reduce damage due to shrinkage cracking. A minimum 4 inch thick layer of free -draining gravel should underlie basement level slabs to facilitate drainage. U,,NDERDRAIN SYSTEM Although free water was not encountered in the exploratory borings, it has been our experience in the area and where clay soils are present that local perched groundwater can develop during times of heavy precipitation or seasonal runoff. An underdrain system should be provided to protect below -grade construction, such as retaining walls, erawlspace and basement areas from wetting and hydrostatic pressure buildup. The drains should consist of drainpipe surrounded above the invert level with free -draining granular material. The drain should be placed at each level of excavation and at least 1 foot below lowest adjacent finish grade and sloped at a minimum 1% to a suitable gravity outlet. Job No. 105 897 DEC -06-2005 13:49 H -r 'EOTECH _9 - SUE GRADING The risk of construction -induced slope instability at the site appears low provided cut and fill depths are limited. Cut depths for the building pads and driveway access should not exceed about 10 feet Fills should be limited to about 10 feet deep, especially in steeper sloping areas. Structural fills should be compacted to at least 95% of the maximum standard Proctor density near optimum moisture content. Prior to fi11 placement, the subgrade should be carefully prepared by removing all vegetation and topsoil. The on- site soils excluding oversized rock and topsoil should be suitable for use in embankment fills. Permanent wreathed cut and fill slopes should be graded at 2 horizontal to I vertical or flatter and protected against erosion by revegetation, rock riprap rpt other means. This office should review site grading plans for the project prior to construction. SURFACE DRAINAGE The grading plan for the development en the property should consider runoff from steep uphill slopes through the project and at individual sites. Water should not be allowed to pond which could impact slope stability and foundations_ To limit infiltration into the bearing soils next to buildings, exterior'backfill should be well compacted and have a positive slope away from the building for a distance of at least 10 feet. Roof' downspouts and drains should discharge well beyond the limits of all backfill and landscaut, irrigation should be restricted. LIMITATIONS This study has been conducted according to generally accepted geotechnical engineering princililes and practices in this area at this time. We make no warranty either express or impii„d. The conclusions and recommendations submitted in this report are based upon. the data obtained from the field reconnaissance, review of published geologic reports, the exploratory borings located as shown on Figure 1, the proposed type of construction and • our experience in the area. Our services do not include determining the presence, prevention or possibility of mold or other biological contaminants (MOBC) developing in Job No. 105 897 Gt P.12/21 DEC --06-2005 13:49 H -F -OTECH - 10 - P.13/21 the future. If the client is concerned about MOBC, then a professional in this special field of practice should be consulted. Our findings include interpolation and extrapolation of the subsurface conditions identified at the exploratory borings and variations in the subsurface conditions may not become evident until excavation is performed. if conditions encountered during construction appear different from those desc:ibed in this report, we should be notified so that re-evaluation of the recommendations may be made. This report has been prepared for the exclusive use by our client for planning and preliminary design purposes. We are not responsible for technical interpretations by others of our information. As the project evolves, we should provide continued consultation, conduct additional evaluations and review and monitor the implementation of our recommendations. Significant design changes may require additional analysis or modifications to the recommendations presented herein. We recommend on-site observation of excavations and foundation bearing strata and testing of structural fill::by a representative of the geotechnical engineer. Respectfully Submitted, HEPWORTH - PAWLAK GEOTECHNICAL, INC. Jord.y Z. Adamson, Jr., P Reviewed by: Steven L. Pawlak, P.E. JZA/ksw cc: Mountain Cross Engineering, Inc, -- Attn: Chris Hale Job No. 105 897 systecrl DEC -06-2005 13:49 H—P 'OTECH -11- REFERENCES Frankel, A.D. and Others, 2002, Documentation for the 2002 Update of the National Seismic Hazard. Maps: X.S. Geological Survey Open File Report 02-4200, Kirkham,, R.M. and Others, 2002, Evaporite Tectonism in the Lower Roaring Fork River Valley, West -Central Colorado, in Kirkham, R.M.., Scott, R.B. and Adkins, 1 W eds., Late Cenozoic Evaporite Tectonism and Volcanism in West 0,?nt,ral Colorado: Geological Society of America Special Paper 366, Boulder, Colorado. Kirkham, R.M. and Others, 1996, Geologic Map of the Cattle Creek Quadrangle, Garfield County, Colorado: Colorado Geological Survey Open File Report 96-1. Kirkham, R.M., and Rogers, 'W.P., 1985, Colorado Earthquake Data and Interpretations 1867 to 1985: Colorado Geological Survey Bulletin 46. Widmann, B.L. and. Others, 1998, Preliminary Quaternary Fault and Fold Map and, Data Base of Colorado: Colorado Geological Survey Open File Report 98-8, • Job No. 105 897 P.14/21 DEC -06-2005 13:49 H -r 'EOTECH P.15/21 i 6860 6840 6820 • BORING 2 / ROAD EASEMENT 1 6800 BLACK DIAMOND MINE ROAD FRAMED DUGOUT STORAG BUILDING • • BORING 1. \ EXISTIN CABIN% \ .RESIDE E LOT 1 ART STUDIO OFFICE LOT 2 1 6860 \ _ CENTERLINE 10' UTILITY EASEMENT 6840 6820 PROPERTY BOUNDARY 6800 6800 6800 APPROXIMATE SCALE 1" = 180' LOCATION OF EXPLORATORY BORINGS Figure 1 ..111.6....,. DEC -06-2005 13:50 N 10 15 20 H -P .c'OTECH BORING 1 ELEV. - 6858' 13112 WC GI 16.8 OD= 105 -200=92 16/12 WC=14.7 CD= 113 -20092 20/6,10/0 WC=20.6 DD= 102 -200=57 98/12 BORING 2 ELEV.,- 6828' r r ' 2$/12 ' WC=14,2 r DD=118 v, 32/12 5 WC =18,7 ti•'� DD=112 2'Y -200=91 n g• 32/12 :1 '.i- i 29/12 P.16/21 25 25 105 897 Note: Explanation of symbols is shown on Figure 3. LOGS OF EXPLORATORY BORINGS DEC -06-2005 13:50 LEGEND: -7 r i H -P -OTECH TOPSOIL_; sandy clay, organics, roots, firm, moist, dark brown, P.17/21 CLAY (CL); sandy, scattered gravel increasing with depth, stiff to very stiff, moist, grayish brown, medium plasticity. GRAVEL (GC); clayey, sandy, with cobbles and boulders, clay layers, medium dense to dense. moist, browns, basalt rock fragments. Relatively undisturbed drive sample; 2 -inch I.D. California liner sample. 13/12 Drive sample blow Count; indicates that 13 blows of a 140 pound hammer falling 30 inches were required to drive the California sampler 12 inches. T Practical drilling refusal. NOTES: 1. Exploratory borings were drilled on November 16, 2005 with 4 -inch diameter continuous flight power auger. 2. Locations of exploratory borings were measured approximately by pacing from features shown on tie site plan provided. 3. Elevations of exploratory borings were obtained by interpolation between contours shown on the site plan provided and checked by instrument level. 4. The exploratory boring locations and elevations should be considered accurate only to the degree implied by the method used. 5. The lines between materials shown on the exploratory boring logs represent the approximate boundaries between material types and transitions may be gradual. 6. No free water was encountered in the borings at the time of drilling or when checked 1 day later. Fluctuation in water level may occur with time, 7. Laboratory Testing Results: WC = Water Content (%) DD = Dry Density (pcf) -200 = Percent passing No. 200 sieve 105 897 worth—Pawfak Geotechnical 111111110041, LEGEND AND NOTES DEC -06-2005 13:50 Compression Expansion % Compression - Expansion % 1 0 1 2 1 0 1 2 H -r ;EOTECH P.18/21 Moisture Content = 16,8 percent Dry Density 105 pcf Sample of: Slightly Sandy Clay Prom: Boring 1 at 2 z Feet Expanslo upon wetting 0.1 .0 10 APPLIED PRESSURE - ksf Moisture Content = 14.7 Dry Density = 113 Sample of: Slightly Sandy Clay From: Boring 1 at 5 Feet peroent pcf 100 Expansion upon wetting 0.1 105 897 1.0 10 APPLIED PRESSURE - ksf 100 SWELL -CONSOLIDATION TEST RESULTS Figure 4 DEC --06--2005 13:50 H -r ' EOTECH Compression Expansion 3 Compression - Expansion % 1 0 1 2 3 4 2 1 0 1 2 Moisture Content = 20.6 Dry Density = 102 Sample of: Sandy Clay with Gravel From: Boring 1 at 10 Feet .1 1.0 10 APPLIED PRESSURE - ksf Moisture Content = 14.2 Dry Density = 118 Sample of: Sandy Clay From: Boring 2 at 5 Feet percent pcf P.19/21 100 Expansion upon wetting 0.1 1.0 10 APPLIED PRESSURE - ksf HeGegteCh • yYOd Geo i�f11G0! n 100 SWELL -CONSOLIDATION TEST RESULTS DEC -06-2005 13:51 H—P -OTECH Compression - Expansion % 1 1 3 Moisture Content = 18.7 percent Dry Density = 112 pcf Sample of: Slightly Sandy Clay From: Boring 2 at 10 Feet Expansion upon wetting 0.1 1.0 10 APPLIED PRESSURE • ksf SWELL -CONSOLIDATION TEST RESULTS P.20/21 100 Figure 6 TZ'd 1±101 HEPWGRTi- PAW LAK GEOTECHNICAL, INC. TABLE 1. SUMMARY OF LABORATORY TEST RESULTS SAMPLE LOCATION BORING I DEPTH NATURAL NATURAL MOISTURE i DRY CONTENT r_JENSlTY • GRADATION GRAVEL r SAND (°) PERCENT i PING Ivo. 200 SIEVE ATIERBERG LIMITS LIQUID LIMIT Job No, 105 897 PLASTIC INDEX r UNCONFINED COMPRESSIVE SrR eG !4 46 PS :"-__6.8 92 MINIM ME 112 30 10 10 10 20. 6 20.6 14 2. 14.2 SOIL OR BEDROCK TYt'E Slightly Sandy Clay Slightly Sandy Clay Sandy Clay with Gravel Sandy Clay Slightly Sandy Clay -4- E m