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HomeMy WebLinkAboutpitkin.planning.246726100011 DOCUMENT LAYOUT THIS FILE MAY OR MAY NOT CONTAIN ALL OF THE INFORMATION LISTED BELOW IN THE FOLLOWING ORDER Summary Sheet Resolution for the BOCC and/or P&Z Ordinance for the BOCC and/or P&Z Determination for the Hearing Officer Administrative Determination Staff Memo Application Public Notice,Acceptance Letter, Referral(s) Letter Site Plan Miscellaneous Plat(s) 2467-261-00-011 6/25/1976 1976 Weaver Area of State Interest-Alluvid Fan 1581 Lower River Rd Lot 14 Aspen River Valley Ranch Weater.Dr.W.R. 4 . 11/22/1976 BOCC No 76-144#189617 No No t ' GF:2467-261-00 Now Lot 14AAspen River Valley Ranch Special Review 1041 Hazard Review i 1/5/2011 FF BOX#189 .eccsded.ot 12:28 P.M. , Decembe4o 1976 Julie Hane, Recorder ption Number: PITKIN COUNTY COMMISSIONERS 8QOK320 PAC 671 RESOLUTION NO. 76 - Re: Weaver Building Permit - Area of State Interest - Alluvial Fan WHEREAS, Dr. W.R. Weaver has applied to Pitkin County Commissioners for permiGsion to build a single-family dwelling on Lot 14 of Aspen River Valley Ranch consisting of 35- acres of land which is zoned AF-2, Agricultural Forestry, and is more fully described as Exhibit "A" attached to this resolution, and WHEREAS, the building site is located in an alluvial fan as described on the Colorado State University Environmental Resource Analysis maps and is designated by Pitkin County as an area of STate Interest by the Pitkin County Land Use Code, and WHEREAS, the applicant is requesting that the Pitkin County Commissioners pursuant to Section 5.40.06 c. of the Land Ulse Code find the followings that . . . hazard conditions do not present a significant hazard to the public health, safety, or to property at the specific location within the hazard area boundary for the particular proposed use. and WHEREAS, on June 28, 1976 a public hearing was held before the Pitkin County Commissioners to consider the issuance of a building permit in a designated area of state concern, and WHEREAS, Mr. Weaver engaged the firm of Lincoln-DeVore, consulting engineering geologists, to evaluate the alluvial fan hazard, and their reports dated May 10, 1976 and June 11, 1976 is attached hereto and made a part of this resolution (Exhibits "B" and • "C"); and K 000001 euuK 320 r;�C 672 � •1 WHEREAS, the Colorado Geological Survey has review the Lincoln-DeVore Geologic Hazard Investigation by letter dated June 25, 1976, and recommended that a building permit be issued to Mr. Weaver subject to the constraints and mitigative techniques described in the Lincoln-DeVore report. NOW, THEREFORE BE IT RESOLVED, that the Pitkin County Commissioners hereby find that the hazard conditions present on Mr. Weaver's building site do not present a significant hazard to the public health or safety pursuant to Section 5.40.06 c. of the Land Use Code and grant the building permit subject to the following conditions: 1. That this resolution, the Lincoln-DeVore report dated June 11, 1976, the Colorado Geologic Survey letter of June 25, 1976 be recorded in the Clerk and Recorder's Office. 2. The building permit be issued subject specifically to the contraints and mitigative measures described , in the Lincoln-DeVore report and those described in the House Investigation Report dated May 10, 1976 by Joseph R. Infuscelli of Lincoln-DeVore. 3. It is recommended that nothing requiring irrigation (i.e. , lawns, gardening, or other landscaping) be placed around the house, in order to protect the property from water damage by promoting good sur- face drainage around the house structure. 4. This resolution and accompanying documents shall be attached to the building permit. DATE: Z Z 2 ATTEST: PITKIN COUNTY BOARD OF COMMISSIONERS lerk & Recorder seph- wa s, Jr. hairman tlk ti 1 r 000002 � n ' ., $OOK�rw� P,t6�s IJ EXHIBIT A A parcel of land being parts of Tracts 70, 71 and 72 and being located in Section 23 and 26, Township 8 South, Range 86 West of the 6th Principal Meridian. Said parcel is more fully described as follows: Beginning at A.P. 2 of said Tract 71; thence N 89°48 ' 20" E. , 369. 22 feet along the Northerly line of said Tract 71; thence South, 2523. 42 feet; thence S 15038147" E. , 1475. 78 feet to a point on the Southerly line of said Tract 72; thence N 86030153" W. , 585. 20 feet along said Southerly line; thence N 05°22 ' 04" W. , 2276. 03 feet; thence N 00033105" E. , 590. 00 feet; thence N 01°18 ' 52" E. , 1051. 96 feet to the point of beginning. Said parcel contains 36. 2015 acres, more or less. J3:;73 f ' i I O Dale Keach and Harold Smith, from the F.A.A. , mentioned that the meter at the airport showed that the lights had only been used for 46 hours in the past year. Gould added that she feared that the lead-in lights would cause Aspen Airways and Rocky Mountain Airways to revert to their old flight paths. The flight paths had been recently changed, which she and the residents of Woody Creek considered a notable improvement. It was noted that the problem is greatest when the ceiling is low and visibility is poor. A short discussion followed on whether the use of these lights would increase with increased use of the airport. Shellman asked if Gould and Anderson would be interested in serving on a committee which would investigate the problem of controlling the usage of the airport by private planes. Both expressed an interest, but Anderson added that aviation experts should be included in the committee. VFR Edwards suggested that the minimumJceiling for usage of the area by small i planes be raised. Shellman moved that the permit be extended for sixty days subject to compliance with the conditions of the existing permit, satisfaction of the complaints by Gould and Anderson, and the establishment of satisfactory controls on the use of the lights. These controls should specify that the lights be used only at the request of a pilot and for periodic main- tenance. Kinsley seconded the motion and it was unanimously approved. It was also requested that a meeting be set with Mr. Martin of the F.A.A. office in Denver. Weaver - 1041 A 1041 House Bill Hearing was held concerning the alluvial fan condition Hearing on the property of Dr. W.R. Weaver. Weaver has requested permission to + build a single-family dwelling on lot 14 of the Aspen River Valley Ranch, which consists of approximately 35 acres of land zoned AF-2. This area is - designated as an area of state interest by Pitkin County. i A report was presented by the firm of Lincoln-DeVore, consulting engineers, i which evaluated the alluvial fan hazard. Shellman commented that the geological work done for this case was very good. He also asked if this were the only factor being considered before the issuance of a building permit. Hal Clark, of the Planning Office, replied that an effort was be- Commissioners Meeting June 28, 1976 - Page 3 000004 ( 0/ ing made to shorten the procedures involved in this application. He added that following this 1041 Hearing the applicant must also satisfy the build- ing permit review procedures. It was noted that the proceedings in the Land Use Code 5.40.06(C) , second phrase, should be included in another section. A motion was made by Kinsley to grant an exemption based on 5.40.06(C) "that. . .the hazard conditions do not present a significant hazard to the public health, safety or to property at the specific location within the hazard area boundary for the particular proposed use", and that the condi- tions in the Planning Office are fulfilled. This motion was unanimously approved. Discussion followed this motion as to the most effective method of notifying the future purchasers of this land about measures necessary to pro- tect the property and structure from water damage, specifically damage from water flow coming down Cerise Gulch and surface drainage surrounding the house. It was recommended that nothing requiring irrigation (i.e. lawns, gardening or other landscaping) be placed around the house. A resolution will be drawn up by the Planning Office which will be recorded, and a copy will be attached to the building permit in an effort to notify future land- owners of the problem. Rubey Estates- A detailed submission by the Rubey Estates Subdivision was presented to _Detailed Submission the Commissioners. Chuck Brandt and Bob Rubey were present to represent the estate. Brandt reviewed the previous discussions concerning the subdivision and outlined the three specific areas of dissention between the Commissioners and the developer. The first item was the option price. The Commissioners had proposed $500 to hold the property for 18 months, and the trustees have countered with an offer of $1,000; the Commissioners accepted the latter offer. The Commissioners had also requested dedication of an easement along i f the Salvation Ditch for future trail use, contingent upon permission by The Salvation Ditch Company and dedication of the other links between the Red Mountain Road and the Hunter Creek Trail. Both of these conditions must be fulfilled before any trail development will be done on the Rubey Subdivi- sion land. The third item of dissention was the request by the _Commissioners Meeting June 28, 1976 - Page 4 t t OJ0005 � p p MEMORANDUM TO: Pitkin County Commissioners FROM: Planning Staff (HC) RE: Land Use Code HB 1041 Hearing Section 5.40.06 - Alluvial Fan DATE: June 25, 1976 This is a request by Dr. W.R. Weaver for permission to build a single- family dwelling on Lot 14 of Aspen River Valley Ranch consisting of 35+ acres of land which is zoned AF-2. The building site is located in an alluvial fan which is designated by Pitkin County as an area of State Interest. The applicant is requesting that the Pitkin County Commissioners pursuant to Section 5.4O.O6c find the following: 1. that. . .hazard conditions do not present a significant hazard to the public health, safety, or to property at the specific location within the hazard area boundary for the particular proposed use. Mr. Weaver has engaged the firm of Lincoln-DeVore, consulting engineers, to evaluate the alluvial fan hazard. Lincoln—DeVore has referred their report to the Colorado Geological Survey for analysis and comment. As of this writing we have not received the written comments of the Colorado Geologic Survey which are in transit to us. However, Dave Shelton the project reviewing officer of the Geologic Survey has analyzed the report and recommended verbally to us the following: 1. He believes it to be an excellent, professional analysis of the alluvial fan hazard. 2. The building permit should be issued conditioned upon the hazard mitigation suggestions outlined in the Lincoln—DeVore report. 3. In addition, construction supervision of these mitigation measures should be performed by a licensed Colorado Engineer. The Planning Office recommends issuance of the building permit upon receipt and acceptance of the comments of the Colorado Geologic Survey, and conditioned upon the requirements suggested by Lincoln-DeVore. Attached is the applicant's application; soils report; and an alluvial fan analysis of the property. 000006 MEMORANDUM TO: Pitkin County Commissioners FROM: Planning Staff (HC) RE: Land Use Code HB 1041 Hearing Section 5.40.06 - Alluvial Fan DATE: June 10, 1976 This is a request by Dr. W. R. Weaver for pi- mission to build a single- family dwelling on Lot 14 of Aspen River Val ey Ranch consisting of 35 + acres of land which is zoned AF-2. The building site is located in an alluvial fan which is designated by Pitkin County as an area of State Interest. The applicant is requesting that the Pitkin County Commissioners pursuant to Section 5.40.06c find the following: 1. that . . . hazard conditions do not present a significant hazard to the public health, safety, or to property at the specific location within the hazard area boundary for the particular proposed use. Mr.Weaver has engaged the firm of Lincoln-DeVore, consulting engineers, to evaluate the alluvial fan condition. We have asked Lincoln-DeVore to refer their report to the Colorado Geological Survey for analysis and comment. As of this writing we have not received the comments of the Colorado Geologic Survey. Should the report by Colorado Geologic • Survey recommend approval of the alluvial fan report and the issuance of the building permit, the Planning Office recommends approval of the request. Any mitigation techniques suggested by the report should be included as conditions of permit issuance and enforced through the office of the Building Inspector. Attached is the applicant's application and a soils report on the property which is in addition to the required alluvial fan analysis. Q(�QUo7 5.40. 06 APPLICATION Board of County Commissioners Pitkin County, Colorado Gentlemen: Dr. W. R. Weaver submits the following application pursuant to Section 5. 40. 06 of the Pitkin County Land Use Code to exclude the land described in Exhibit A, attached hereto; (the land) from a designation as an "Area of State Interest" and as grounds therefor states: 1. Applicant has made application for a building per- mit for one single family dwelling on the land. 2 . Applicant has been advised (1) that the Building Inspector would not issue the building permit because the building site was within an alluvial fan, (2) that as a result such land is designated as an "Area of State Interest" , (3) that an opinion of a qualified engineer to the effect that no hazard exists in constructing the proposed dwelling if certain steps are taken would be required to support an application to modify the map designating the land as an area of state interest. 3. Applicant has such an opinion and has attached hereto a copy thereof as Exhibit B. 4. There exists no valid reason to include the land within the designation of "an area of state interest" in light of the expert opinion attached as Exhibit B. 5. To require applicant to make the requisite filings ,under the special review provisions of the code would support no part of the Land Use policies expressed therein and would create a severe hardship on applicant in that: (1) He has scheduled construction of the proposed dwelling based on his belief that the building permit would be immediately forthcoming, and has already completed his water well and building excavation. (2) To make all filings suggested by the special review proceedings would take several months to process thereby disrupting all pre-established building schedules: (3) To be required to process an application through 000008 Board of County Commissioners May 14 , 1976 Page 2 the special review provisions of the Code will significantly add to applicant' s expense of develop- ment. Your favorable consideration of this application will be appreciated. , Very truly yours, Dr.�v. R. Weaver Dated May 14 , 1976 000009 EXHIBIT A A parcel of land being parts of Tracts 70, 71 and 72 and being located in Section 23 and 26, Township 8 South, Range 86 West of the 6th Principal Meridian. Said parcel is more fully described as follows : Beginning at A.P. 2 of said Tract 71; thence N 89048120" E. , 369. 22 feet along the Northerly line of said Tract 71; thence South, 2523. 42 feet; thence S 15138147" E. , 1475. 78 feet to a point on the Southerly line of said Tract 72; thence N 86030153" W. , 585. 20 feet along said Southerly line; thence N 05°22 ' 04" W. , 2276. 03 feet; thence N 00033 ' 05" E. , 590. 00 feet; thence N 01018 ' 52" E. , 1051. 96 feet to the point of beginning. Said parcel contains 36. 2015 acres, more or less. 0000 Q L THE LINC©LN-DeVORE TESTING aBORATO4Ply % 73I0 GI••�..•w MEMSERi A.S.T.M. Gowpe D.Monle, P.E. ��••••�srl+,.. C.1..L IIe01 A.S.C.E. fr3ane CEC ACI •...,c.l.,.e. nue n7-,ta EXHIBIT B S'il V Ice F Ev, May 10, 1976 n Air. William Weaver Snowmass, CO 81654 C M;. Res House Investigation Weaver Residence Pitkin County I` Woody Creek, CO hU qn Dear Mr. Weavers c l I°" Personnel of this Laboratory have inspected the foundation excavation at the above referenced . G,< ,e, site to determine subsurface soil conditions. We have also H Y reviewed the Structural Engineering report submitted to •you by Mr. Roger Hocking of Eldorado Engineering of Glenwood Springs . Recommendations and comments for this site are F a shovm belows °t Soil classifications Soils on this site were found to consist «, „a of red-brown angular silty c-f GRAVEL with a trace of clay containing weathered rock fragments up to 12 inches in dia- meter locally derived from the Maroon Formation to the north C "'"pe' of the site. This soil appears to be low expansive in nature. C. ° Man-made fill: None - soils are native to the site. C Moisture conditions at time of inspections Low to moderately How 0°mp moist. R° �Q1m��ti22Lt..'P, r� mm��dgds The foundation design recommended by I1r. }locking tikes the on-site soils into direct consider- EE ation. Due to the nature and depth of the .rear foundation e cuts, it is imperative that the design parameters mentioned Glen' nqe' by Mr. Hocking be followed. Also if there are any changes A" 'd°Randn'I in design concept, vie suggest that Mr. Hocking be made nnolly Ee . >hmen aware of these changes. 9 ie y� Lee F. mail 00001 �. V Air. William Weaver Page 2 Voids jeneath foundation walls Not required. Reinfo cinei The reinforcing recommended by Mr. Hockings' report appears to be quite adaquate . Additional #5� rebar should be placed at 45e at any steps in the foundation wall, and all reinforcing should have a minimum lap of 15" - Floor slabs on grade should be ' positively separated from all structural portions of the building and allowed to float freely . Non bearing parti- ;, tions resting on slabs on grade should be constructed with a void space , at the bottom preferably, to allow for freeaoF of movement without affecting the roof or floor above . Bear- ing partitions should have their own foundations. If base- ment type construction, or multi-level structure, stairway between floors should not be constructed as a rigid connect- tion, but should allow for vertical movement in the floor slab. Drainage and�rad.in�and�rad.inn Surface grading should be constructed in such a manner that all runoff moisture is removed from the vicinity of the structure as quickly as possible . Roof drains , if any, should be carried across backfilled areas and allowed to discharge well away from the building. Watcr • should not be allowed to stand or pond in areas of backfill. To aid in keeping water from reach- ing•the soil beneath the building, all backfill should be treated. 1 . Backfill around the building or in utility trenches leading to the building should be mechanically compacted at the optimum moisture content of the soil to a density of 90% of maximum Proctor density, ASTM D-698. With this method, no backfill may be jetted, ponded or puddled. 2. The site and fill material may be presoaked for j a minimum of three weeks prior to construction I until water has entered the soil for a depth 'of at least 3 feet. j` 3. If a perimeter drain is used, this construction .::would remove the necessity for compaction except ' in utility trenches leading to the buildin ;. 00001.4 Mr. William Weaver Page 3 All concrete in contact with clay soils should be made using Type II or Type II LA Cement. Remarks► 1 ) A peripheral foundation drain is highly recom- mended on this site due to both the perennial runoff in the area and also due to the drainage system which lies to the north. A diagram of a typical French drain is enclosed for your utilization. Respectfully submitted, THE LINCOLN DEVORE TESTING LAHO TORY Joseph R. Infasce li JRIAme Enclosure 0000]3 4 (%TES s 11imension of pipe to foundation s same with either footing or \ stem wall only. Place pipe as ihown at the highest point in ce.,r..crcta the line, then grade to outfall. Ner+v6 Ser. ;ize of perforated pipe sand filter cries with amount of seepage ':pected . 411diameter is most common. i 54ND Krl,ree ' ,'' • ., V F N SOME CASES-ONLY o 'D � 'INOR AMOUNTS OF WATER, THE LPE MAY BE ELIMINATED ENTIRELY. rAx!0.raw °c op 9° o eD ° cK DBwrrM ° u o b '•_ 1p ° ° 0 0 Dimension 'D1 depends on pipe n n P YVo • o dyoo size and could be expressedt Pipe + 61' + 211 , normally. N.rci B=P'VWM 18" i+ n ..here pipe is not used, gravel p'^""T'R P06Y ck"&MD A."Iµs'r limension should be computed as if seer^4E LOSS. M N. a 41, pipe were used. s ' No SGe.�E FILL DATAt .Gravel size depends on size of j pipe perforationst 85% gravel > 2 x diameter of ? perforation. C."PkCTWO .Sand filter must depend on e ~^^"`s°" native soil & must follow the Terzaghi-vicksburg Criteria: 0 7 1. 151y. filter 4 + '., • : ` : Sne.o 15% base " 2. 15% Filter < 4 0 0 ° F 85% Base IF ORHDCNr 0 OR tack 00 . ° n °ic"'N 3 . 50% Filter o 12 to 58 °v PcececNTED 50% Base �-n ' R►t M.rfi e.R.t+Id' This is required for stability and length of filter life. TyPlc-L. FLG1N&TCC GeAry . .Conditions can vary considerably, "�- Ar U006D+M4K. F60vw^TIIN and each site may be variable a£, 000014 ova , to quality of rand or gravel /cic� rec+uir :1. TYI'ICAhL SECTICNS LINCOL"-D, a;)FE T.ISPING L'.RO1�.TGhI I nflf•l2]1 i • fnn r rlr c nr.r.^+n L.nn 9 5. 40. 06 APPLICATION Board of County Commissioners Pitkin County, Colorado Gentlemen: Dr. W. R. Weaver submits the following application pursuant to Section 5. 40. 06 of the Pitkin County Land Use Code to exclude the land described in Exhibit A, attached hereto; (the land) from a designation as an "Area of State Interest" and as grounds therefor states: 1. Applicant has made application for a building per- mit for one single family dwelling on the land. 2 . Applicant has been advised (1) that the Building Inspector would not issue the building permit because the building site was within an alluvial fan, (2) that as a result such land is designated as an "Area of State Interest" , (3) that an opinion of a qualified engineer to the effect that no hazard exists in constructing the proposed dwelling if certain steps are taken would be required to support an application to modify the map designating the land as an area of state interest. 3. Applicant has such an opinion and has attached hereto a copy thereof as Exhibit B. 4 . There exists no valid reason to include the land within the designation of "an area of state interest" in light of the expert opinion attached as Exhibit B. 5. To require applicant to make the requisite filings under the special review provisions of the code would support no part of the Land Use policies expressed therein and would create a severe hardship on applicant in that: (1) He has scheduled construction of the proposed dwelling based on his belief that the building permit would be immediately forthcoming, and has already completed his water well and building excavation. (2) To make all filings suggested by the special review proceedings would take several months to process thereby disrupting all pre-established building schedules. (3) To be required to process an application through 000015 Board of County Commissioners May 14 , 1976 Page 2 the special review provisions of theeofldevelop- significantly add to applicant' s expense ment. Your favorable consideration of this application will be appreciated. Very truly yours, 1 i Dr. . R. Weaver Dated May 14 , 1976 000OI6 THE LINCOLN-DeVORE TESTING LABORATQ�(tY 800 PACE 678 MEMBER A.S.T.M. George D.Morns, P.E. 1000 W. Fillmore A.S.C.E. Colorado Springs, Colorado CEC 303-6332--3593 ACI a►an! 116 19716 DATE RECEIVED ASSIGNED TO DATE RE"L.:" -3 ROUTE Soil Testing Mr. William Weaver - -• ieowsnns, Colorado 81694 — — Foundation 22.�. .y Evaluation de,, Lott at fsMa �1�1i.— itk� 92 Materials Tests Dear Me Meaverr Concrete At Your re,quest, personnel Batch Design of the Laboratery have eusminsd a proposed building site located in the *urtbeast 1/4 of Section 26, Township a South, Asphalt Mix Design Mange $6 Most of the Sth wrineipal XOrifian is within Couaty, Colorado. this property is about two miles seat of the voml- Geologlc Sanity of (014) Saowmmas, Colorsde, and oovetots of about 34 Interpretation acres of land situated at the South of Cerise "lab on the north side of the valley of the Mating work liver. Groundwater Hydrology whysiegraphivallyt the by property NOT be described as a 4ebris�lo An (or allenial bw of moderate steer at the time of the field investigation, Registered a large excavation for the foundation of a reaideatial strae- Professional tare was located en the eppor part of the fan. an this Engineers property bee been designated as a geoiogia hazard area by Geologists within County Dudes the provisions of Colorado house sill 1041 (Title 240 Article $Set, Colorado ltevised Statutes 1973 Colorado as amended) and Section Se41.42i of the witkis County Land Coronae,Colorado use Cade due to the presence of the debris fan, the purpose of this investigation was to determise the degree of hazard Pueblo, actually present on the site and to present satiable matbods Colorado for the mitigation of the hen&rd. investigttive techniques included om-site inspeetioa, the collection of surface, and Rack Springs, sabosrfees density test samples, the secavatisa and legging Wyoming of a test pit, lmberatery testing of veil sesples, analysis Glenwood Springs of 4mta, aerial phetographo, &rid geologic litoraturst add a bydrelogic study of the Cerise, Gulch beeline Montrose sodroek in this vicinity Gunnison, Colorado Consists of the Karam and State Drifts formations of lets !l! 000017 Mr. Williaar'�roaeos �t� June 11, 1976 BOOK 320 FACE 679 3 Pemnsylvanias and Perwiam age (about 310 million to 230 million years bstoro the present). !keno two forsotto w consist or awe than 4*000 toot of roddiab-arlorod siltatoeos, clapstarac, and AdMJA (soot&Uin* the feldspar miaorals) assistance. The two formatia w inaluO* the eoquesoo of sod woks exposed an the Mountainside above and to the nsrtb of the property is gmoctiam. aagimming about 70 to 75 willies years before tbo present, much of wasters Morth America was uplifted from a sear-sea level "mitten by a series of crustal movements known as the I&ISM! formiq a sort of mountains wbick were the immuaiato aneeatoro of tbo prosont-day soutbers Reeky Mawntaiia. Thin pro- go" brought the Norman and State arid" rooks from their far via" doeply-buriod position to one Weak clues to the ground surface. To uplift of the mountains was aosounpasied by aom- eiderable folding and breaking of the rocket with sae result of this deformation being Us development at the Castle Creak fault system (wlrioh now rums also** and eastrols the position of, the MOSSLs* Pork valley in Us vicinity at the site) . following the Lasamido orro*esy, there was a period of oroaiea and volcanic ac- tivity in whisk, the mountains were wars darn to a gentlo upland. Then, about too to twelve millioa year* *gat uplift was roamed to form me models Soutborn !tacky m wntains. dais rosow" up- lift wns 000ao"aied by the formation of the Colorado River *"- toes imeludin* the Rearing Pork lbws# wbiab quickly eroded a wilsy into the ease of fractured and altered rook within the Castle Crook fault now. by the begiaml of the glacial period* ('lee Ages•) of to Pll istoo"M *peaks about 1 willies years apt the Roaring Park valley had developed to measly its present form am apfoasamae. The valley at this Is"- tuft was act directly affected by the Pleistocene alpine *inners themselvur bawaver* a eubutantial thickness of outwash Material and alluvium wan dopoetted in the bottom of the valley as flood- plain and *tire" terrace deposits. Us cod of the last glacial period* Most 10*Oo0 year* ago* marked the end of widespread deposition at oodioasts on the valley floor end opened a period Of general orseioa wbiah "a oaatinu*d, with a raw short bracket to the present day. d water product of this period of arumiea has bass the miser depositional feature knows me the Okla b . Debris room are, formed is and and aomi-acid climates A" #lasb Else" induced by sedden, violent precipitation events sweep large quantities of &oil* rack, and other material down stay► "Was and casywas and dump that materiel in a farshaped heap mess the mouth at the gully ar easy" at the saga at the larger valleys no debris fan present on the property at Coriee Ouleb Is build of material derived free the Marcos and state aridge oo�oa_8 rr�f Mr. Willi" war `"� BOA20 {'AJ80 Jame Its 1976 VW* I arossatieao, No is **armed Of angrlar rook fragments raging fret less then an inch to several test in diasatsr, is a silty end sandy matrix scataiaisng a little slay, carts of the flow are waakly sweated with slay and a gwmtity of metal= carbon- ate to tors a variety of A test pit excavated iota the tan at a point just north of the existiag tousdatioa osp- vatien revealed the preoesreo of six distinct layers within the uppesmeot 6.1 foot of the flows. These layers tdssaribOd is a lop spread" to this rorort)aro believed to repreeeat dagacits loft by iadividual debris flow, sad raps in thiaaaeas trees 0.6 to 1,7 teat, tsaoatb tha 6,I-foot towel is a layer of boulders with diameters of several foot, probably representing as older flow of largo magnitude. the total area of the debris tea to an rho order of 267500000 square toot, As the teat pit was located abort two-tbirde Of the way between the tear and the apex of the tan, the oeasured thi.dtaeas Of the flow deposits in the test pit am be taken as a somewhat conservative first ap- proximation to tho everage thidtsese of the deposits Over tbo satire tea. Multiplying deposit thimikasesoe by the total area of the too, it ado be oesa that the velamo Of the last few debris tea deposits rampas foss about 196509000 sable dust (for the 0.6- feet deposit) to about 4s6759,000 eubic toot (for the 1.7-fiat deposit), Maine an average is-plane unit wigbt for the debris flow material of about ng pouads pro cubic tout (detarwtwd from On-site dsaeity tests) , it ores be soon that the weight of the deposits rapes from about $01,050 tugs to about 22ls075 tons. Carlos dalah, whiab boa supplied the material ter the debris tea, drains a total area of about 7" sores, This basis sea be sabdivided late five subboolas, labelled a threogh s en the attashcd map and suomary sheoN. Chased prO- lilo slopes range free eligrbtly mars tboa 33% is the upper parts of the basis to a little eves 0% on the tan itselt, store an the sarromadLay billeideds are indicated by the eaatoor lines an the attached maps sod range or to almost vertical. Altbemgh the slopes withia the Main, are fairly tbickty vegetated with acres troec and various waiters, the slopes are sufficiently stoop that me vegetation ssuld prevent the mass wasting of tar" quan- tities of datritus from the exposed bodrodt and weathered bed- radt, tine-grain" material ie aaatiaseally being w►abad late the channel of Cosisa irlch by rwtt waters, and larger 600M No boulders are likowiso being added to the pile by a eombima- ticn of water effects treat wedging, and gravity fall and move- mast, Tbis louvre material is pcuriediaally flusbad from the Nrlab by flasb floods to @Arun the debris flows tba wolves. A bydrologis study of the 000019 004 bens. lriiliom Neawr bOU9320 PAMUv-L crane 11� lied ► 4 boola was perfeeswod using notheds developed by the w9la 8*11 Co wervatim Services with values ter both assweslt sod rais- fail rwoff being input. It was tiasewred that a sse-bear rainators having a rocurreace interval of 100 years gave a mz- Imns design flood, with a peak flaw of 'ti cubic tort per **cased Ming attained at a time of 0.7 hears attar the beginning of emess precipitation, Details of the hydrologic* analysis are given so the amsery sheets attached to this ropert. Altbosgb larger floods have bo ms and will be, esperieseed is Carlo* oulobs the *anima 100-rear flood repr000nts a reasonable desip flood frequency interval for this site. The total velum of water resulting free seek a flood to appresinately 1,2156000 cubie trot. svideace was found so the site to suggest that at least sue such flood (and debris flow) has occurred hate since the beginning of xottlemat. !rhos the flood velama pl- estated slew is compared to the vol- es of the various debris flow dopssites it ass be readily sees that each debris flow vast oweist of frog two-thirds to these-gwrters solid naterial and frou One-third to one-quarter water by veto** Tberofurss the actual peak flow wbicb should be axed for doeiga perpsees es this rite will be about throes er foot tines the meant conpted by the hydrologic assysis--abort 19100 to 10450 cable fort per reseed. he the hgdraulie properties of the veil- and rook-laden debris flow are different than those of a water flood of *goal aagaitudos the flow vales* "a be takes an only approsiostims to analysing the actual behavior of the debris flow. As the abomel of Cerise llsleb leaves the montains and otters the valley, its Orients- tuft abreptiy ohanyes from seuthwast-flewisy to soetboest-flowing. is the process of makisy this 906 tarns the channel flow along the extresemerthoastern edge of the fang turning a deep gaily. Me golly is evidently a very nedern features having developed slow the last major dobris flow. its the mitigation of debris flow basards requires wither the diversions dnwnimgs or obumoliaa ties of the flows it is apparost that any nitigatim uerk nut be dono at ens near the point where the Channel emorges frog ito sobyou and +rakes the two, Ties presence of the iaciaed channel is the gully an the gas **"**to that a combination of diversion and cbanmolisation techniques would be the Wort desirable niti gatios option. at a peiat Jett inside the gamy" of Cerise South (asat point 3 on the attached map) * the channel is three toot wide at the bases is foer foot loops and 000020 J*" lit 1074 OUQK320 PAC E682 bas bank elopes of about 0.4/1. Assuming a profile elope of about a% am an •n* valuo at 0.05s the Maturing ogeation for flow so open channels indicates that this channel we acaomsdnto a now of about 210 eruble feet per seemed. A short diotwwo dowastropar, after the obannel bas berm its turn toward the sostlaast, the erhsmol prepos is about six fat wide at the base, is about f+eor feet dsop, and has bank siepee Of about 1.5/1. Again assuming slope and •a« values of ha azd 0.05$ the Ma"4019 sgoatien indicates that this ohannel will take about 'flu cable feet pee, soMomd. !iris lower ehaamcl is, howovea, incised within a gaily with a depth (Dmola- sico of the inner abaarel) of abort eight foot. lire Masel" egaatiom iadfosteo that this obaramel sad gaily will handle a flow of about 2,100 ease foot pot seosni, it is apgoreatrt that a 100- year debris flow am mmot be oortainod within the bank* of the ex"ting sha n" la the oenyon sbore the fan, but that the sears flies Sam be hold within the banks of the gully on the fan itself. U* key to the control of dabris flows OR this fen appears to in- volve the diversion and turning of the debris flow into the gully. 04 the basis Of this the best a meet economical structure to mitigate, the hazard ap- : nd pears to be a protested earth erbaakesot. lbie t sbozld Present an almost-vorrtioal armored face, to approaching flows, and Should be eoastruotord with a grossest-ohaped plan to tarn flows Into the gully. fte aumoting of the upstream taco man be dome by OGUV MMAM (ruck-filled wire baskots) for this portion of the onbembe nt. !be, embankment should be a mialsom of about 12 foot high (esaeutord from the ON serfsce) Is front of the oanyen north, and should be tapered down to ground level after the flew bus base turned and contained in the gully# the additional height of the embankment to necessary to o"taia local high flow levels due to backwater and other interference offsets associated with the terming of the flaw. it should be pointed out that, it tbois strracturo to built, it will also be necessary to eonstroct egoal" eewtzel works in the obanmol and gully itself. 9ro be specific, It will be necessary to protect the gully wall directly beneath the embeakmant to avoid undercutting that structure. Ibis use be does by armoring the gully wall with gobisns carried do" to s level below the channel bottom. A specific desiga tog the pro- toetivo structures dorseribed above can be provided on request, It s noted at the time at the field iavestivatiom that the normal flow of Cerisoo folorb bad been diverted hoar the head of the ism late an abandoned obzfmosl. This channel is being used to conduct the water into a small pond located slightly to the north and west of the proposed bazee. If it is desired to maintain this ,pond► a moans meet be previded to 000duet the noraml flow of the 6al4h tbrougb the ftbaskment whale unn2i Mg. Milliam�i ver '"' • rr��ryryn� June il, 1976 BouK320 PnE663 cgs Preventing debris flow free taking the rase route. This out be does by meaw of a ssall-diau*tsr culvert placed in tM embaskaost at tM diverst" plat. !Iris installation abould be designed as a dam outlet, and should be constructed with setoff Sollars and othor appropliato features to prevent piping erosion within the embask*+at. Finally, it east be reoegnised that a aster debris flow, even if contained by the meant, will cocoa aiinifiaaat damage to the protective works. At a minimus, the Channel and eebaaheoat will have to be cleaned out after every flow. It is likely that repairs to the entire mitigation system will haw to be $ado. The mpease of maintaining the mitigation wefts east be as$esed as one of the costs of developing this site. Kentiaa ebosld be made of another goslogio problem wbiab is present as the site. Whom frog- moats of soil and roost are deposited by debris flows, they are eutorssaly laid dswa in a very lasso grain framowork--s "skolotoa" soil $tractors. This vorylesre $treaters is held together by the coasatiag actiost of wall quantities of clay and mdcium carbonate wbicb ago present between the individual soil and molt grains. Nbon the soil is soaked by water, the astural comsat softeas sad dissolvesr if the roil is loaded ft.e. by the woigbt of a boaso) „ the Cement fails and tbo sell collapoes--tbe pboaceesse know as bvdresawanatIM. Debris flow derived from the iatrson formation are notorious for their bydroeoajoativo tendencies. AesordiM1y, the soil of the debria fea was tested by the metbod of eibbs and Mlland(ti.s. suroaa of Acclamation snr. hone. 2*9 P. 22-24I, in which the in-place density of the sell is compared to the liquid limit of the soil. Results of the toots performed spa soil sasa- plas free tbis site indicate that the soil is indeed 1t1►dreasorpec- tive. Xatorprotatioa of the results suggests that the sail is capable of sottlLag by at least 1249% of its height. This foot suggests that pro- Stations should be taken to aware that the soils sadertyiag the fouadatica of the bouse sever booms saturated. Careful attes- tisa sbeuld be paid to surf&** drainage to a" that all prootpita- tion drains quickly from around the Muss. Algol it is not ree a- mended that 140110, gardens, or ethor landscaping reptiviag irrt- gaties be placed around the brew. It cal► be advisable to car- fouM the bane with an impermeable layer of same sort to anboace surfaso draleago and prevent water infiltration. Care should be taken in the placement of water and wastewater lines to make saro tbat no leakage occars► it there is a possibility of leakage, stops should he taken to control and limit the penetration of water Late the soil* finally+ it is suggested that the founds- ties design be reviewed by the structural engineer to sae if it 0,00022 itr. lsilliam N�ieaver "" .Tugs 11* 1976raff e ,....__..._ emataiss scftielost stool to bri4e over any local eollapsd areas ritheot damagLaw the strustcrs. It is believed that all pertinent POLO" saceenmw the prsplem hoes* ON the aet&ss Galoh da►ris fan have boss oevored is this report. It gsac- time arias or sthor informatics Le dosired* pleas* feel free to anstast the TAUMMtery at any time. Very truly yours* Li�X Oxo is legist 000"e D. n ertis* V.S. st %* of Colorado 2051 W.,4 'e, 4-4<4 Joseph R. Iafasaa li trolessiosal 8eolegist Q00023 "V:1; .�h\•�`��/-.SKI vt.f _� �.f�.tt i.j?�fi. ..i\`��/j�-;�! ,1 ,:, ,�;P ;�.t! .a-- - .i,�._�� _ . •%// FT v:�r..f'lf�. Y,{ 'r/ !r� � '/`�1 t- +• / '{1`' J � 77 ` � -l r{ �i?�1., r - � � 1T•ri` 'i��'�i� �J ,�' tr \w./'`/'� 'f r 9 ;• t,1�( FIl it rr, i.+ XI m1a ,r i �� I{il flt, 1 u; \4 •: ,12! 1 '„y `t•.r � �"^'f t�ti _ ���3 -_ �y (rl �O �1�1,y.-��-r \� '� j � l� \\ ��", \ . Au =�sr rj -'1: :'.� � .-W lam\ C'RANOE _ �QRYj C�. 'f•�r�,`•; _�.- � � A. }1r tEy� { �� . '`^•.,�, ref �kzT�),�- 5' L--.-� e`�ft ��``^. e�/J%'�l ,i �'...'*.'� �� - rF(�' �:�r�Jl 1r���,.`� •. i�F . I = 2000, i,4:k DEBRIS FAN STUDY THE LINCOLN-DeVOREYTESTING LABORATORY WEAVER PROPERTY (Cerise Gulch) CALORADO Colorado springs, Pueblo, Glenwood WYOMING Rock S�ri PITKIN COUNTY COLORADO Springs,Montrose,Gwmison. • `■' V� BOOK320 PAGERSG ,J oM ri rn � I iu M z � M F'1 010 o Ln m f ago O O $ V N M N -+ M m N 0 3 0 u 41 O '� E" .0 O c: rn a CN m �'+ v lf't r O r I I N O x 0 1+ 1a CO u1 'Vl N .0 .0 Of ui d I `r' I o A 0 N d' M N N Z N C4 m r M m Cl� lfl Ln H �z] W OO 0 0 M a �ryND-+; O i-�Z lf1 M i mI co C) CO co CO co m y O S4 H W� � E tr ° E U U UI U I Ir Cv 04 O m o f �n of O z m 0 a' No o H 0V C I � x m o 0 I EU,a (V l0 O Ir- co co O .0 r CD N O M I r ra p ri U Q 00 00 O O .10 ,..� 0 ++,o O 0 m m O O CO 0 O l0 w Ln r F •..{ d, M � a C7 x O o 0 0 o Q C0 O N mfu En I ,4 o o o of of z o O o , a r M to 001 �M-I' I HO I F of Ohl r — of m j C4 U)ti �I O M 4-4 CO r r 0 H a H 14 UI I 060025 007 ' 1J m vl � y tT N i i U �O V. I I H LnO M a m � u j I N N rOi O ! j 0 .3GV ul i 1 H bl a j, j CQ O A ow o ! j Na E , H H H E F a w al 0 r4 Lk o vl ID � O m � as� MHO o i o m a� i' z m o 44 a S m O E+ to O o k r r r 0 F Z O O o 0 4 o 00 a} I I ri U 04 H I r N N Ln E+ O r O N r G +i � N H j 4J E- O O O o m a F n Ll o ro H � Q H O CDj 4J O O 7 O to O z w r n o O U a r r r H � E 0 o O E j m W i i j m a d of b co 0 o to 0 OH r1 N tell N O O E Q N a W Hz l �- a 000026 n PRECIPITATION DERIVATION: 500K3z0 j'AGCB Values from USDC-NOAA Atlas #2, Precipitation-Frequency Atlas of the Western United States, Vol. III (Colorado) : 24-hr, storm: 2-yr. = 1. 2", 50-yr. = 2.4" , 100-yr. = 2 . 7" , 6-hr. storm: 2-yr. = 0, 9" , 50-yr. = 1. 8" , 100-yr. = 2 . 0" Y100 (1-hr. ) _ . 494 + . 755 (2 . 0 x (2. 0/2 . 7) ) = 1. 61" Y2 (1-hr. ) _ . 011 + , 942 (0. 9 x (0, 9/1. 2) ) = 0. 65" From log curve from Y2 to Y100 , Y50 ( 1-hr. ) i j TEST PIT LOG: Test pit excavated and logged on 06/02/76 . Located north of excavation. 0. 0 ' - 0. 7 ' Angular siltstone & sandstone fragments (up to 1. 5" diameter) in micaceous silty matrix. Color brownish-black (5YR2/1) . Contains some grayish-black cinder material, apparently road base; also some organic matter. Dry and strong. SM-ML. 0. 7 ' - 1. 3 ' Some angular fragments of siltstone & sandstone (up to 3" diameter) in a slightly plastic, consolidated silt matrix. Color dark reddish-brown (IOR3/4) , Contains some minor cal- cium carbonate; moist (water content 11. 80%) . ML-CL. 1. 3 ' - 2 . 3 ' Angular siltstone & sandstone cobbles semi-cohesive silt matrix, Color moderate tbrown (5YR4/4) . Slightly moist (water content 9, 80%) . ML-CL. 2. 3 ' - 3. 3 ' Plastic, consolidated silt, some siltstone & sandstone gravel (up to 3 " diameter) , Cohesive, some carbonate cement. Color moderate reddish brown (lOR4/6) . Moist. ML-CL. 3 . 3 ' - 5. 0 ' Less-cohesive silt with siltstone and sandstone gravel (minot) . Color dark reddish brown (10R3/4) . Moist, shows evidence of i soil development . ML, 5. 0 ' - 6. 1 ' Cohesive, plastic silt, some angular ravel. reddish-brown (10R4/6) . Moist (water g C . moderate tains small fragments of carbonizedwood. ML 105%5/) ; con- 6. 1' Total depth. Bottom on angular Maroon & State Bridge boul- ders (up to 3 ' diameter) . SHEET 3 OF 3 ITHE LINCOLN-DeVORE TESTING LABORATORYORADO:Colorado Springs, Pueblo Glenwood WYOWNG;Rock Springs, ngs,Montrose, Guredson. ODU027 ` Cw ..1 RI eoQK 32U RICHARD D. LAMM GOVERNOR JOHN W. ROLD off, Director COLORADO GEOLOGICAL SURVEY DEPARTMENT OF NATURAL RESOURCES ROOM 703 Pik 8l 8pJ16Q1N6—.845.slitt 4-, 9TRF&1� 1313 .�H EI�i��nN Jflctcl DtIVVER, COLORADO 80203 PHONE 892-2611 June 25, 1976 Mr. Hal Clark Aspen/Pitkin Planning Office 130 South Galena Aspen, CO 81611 Dear Mr. Clark: RE: WEAVER PROPERTY GEOLOGIC HAZARD INVESTIGATION We have reviewed the engineering geologic investigation by the Lincoln-DeVore Testing Laboratory for the Weaver Property at the mouth of Cerise Gulch. This investigation very clearly states the geologic constraints associated with the debris fan on which the proposed house construction is located. The calculations, evaluation, and recommendations of this report appear reasonable to us. As is made clear in the report, this debris fan is active, and thus if construction is to take place, remedial measures will be required. These mitigative procedures recommended by the Lincoln-DeVore report for the 100-year flow appear to be reasonable. As with any statistical analysis as this one, there is a probability of exceeding the design storm and flow. We believe that if the recommendations of the report are adhered to by Mr. Weaver that this area can be developed. We also recommend that the County and owner provide for the transmittal to future owners of the site the conditions under which this structure will be constructed. This way the risk will be known to all potential buyers and the cost of maintenance associated with a large debris flow will be more clearly understood. If we can be of further assistance, please contact our office. Sincerely, J�6- M� David C. Shelton Engineering Geologist cc: Lincoln-DeVore Testing Laboratory Mr. William Weaver Land Use Commission DCS/jp 00028 GEOLOGY STORY OF THE PAST . . . KEY TO THE FUTURE