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HomeMy WebLinkAboutbocc.res.186.1999111111111111111111111111111111111111111III 1111111111111 438010 11/24/1999 12:09P RESOLUTI DAVIS SILVI 1 of 20 R 0.00 0 0 00 N 0 00 PITKIN COUNTY CO RESOLUTION OF THE BOARD OF COUNTY COMMISSIONERS OF PITKIN COUNTY, COLORADO, FINDING A TAKING AND GRANTING 1041 HAZARD REVIEW, CONCEPTUAL SUBMISSION AND SCENIC OVERLAY APPROVAL TO THE NEWFOUNDLAND LODE Resolution No. 99- 18'6 RECITALS 1. Win Win, LLC ("Applicant") has requested development approval following a staff determination that a previous approval had not been common law vested and that application of current Code standards would result in a taking. The approval sought is to construct a single-family residence following a takings determination by the Pitkin County Board of County Commissioners ("BOCC"). 2. The property is located at the base of Aspen Mountain adjacent to the Hoag Subdivision on Ute Avenue, and is described as the Newfoundland Lode Mining Claim, M.S. 5190. 3. The property contains approximately 10 acres and is zoned AFR-10. 4. The BOCC granted Scenic Foreground Overlay, General Submission and 1041 Hazard Review approval to construct a single family residence on the Newfoundland Lode, pursuant to Resolution No. 91- 87. 5. The BOCC subsequently granted an extension of vested rights pursuant to Resolution No. 94-198. 6. The vested rights expired on October 25, 1997. 7. The County Zoning Officer issued a notice of violation in 1996 for excavation of the building envelope on the Newfoundland Lode without permits. Section 7-20-030(E)(2) of the Land Use Code provides that "no land use approvals or building or other development permits shall be issued with respect to the property where the violation is believed to exist during the period of such violation." This outstanding violation has not been remedied. 8. The BOCC heard the Applicant's request at its regularly scheduled meeting of October 27, 1999, at which time evidence and testimony were presented with respect to this application. Resolution No. 99- ! ?(e Page 2 11111 111111 11111E111 IIIII 11111111 IIIII 11111111 438010 11/24/1999 12:09P RESOLUTI DAVIS SILVI 2 of 20 R 0.00 D 0.00 N 0.00 PITKIN COUNTY CO 9. The BOCC finds that the application of Code criteria does constitute a taking of all reasonable use and economic return from the subject property, since there are no developable areas on the subject property that avoid slopes in excess of 30%, or are located outside of severe wildfire hazard and potential avalanche hazard areas. 10. The BOCC further finds that the property owner has a reasonable investment backed expectation to some residential development of the property. 11. The BOCC finds that the property is not appropriate for any use other than residential and that this application proposes development in the best possible location, given the hazards identified on the property. NOW, THEREFORE, BE TT RESOLVED by the BOCC that it does hereby grant 1041 Hazard Review and Conceptual Submission approval for the Newfoundland Lode, subject to the following conditions, which shall run with the land and be binding on all successors in interest: 1. This resolution repeals and replaces BOCC Resolution Nos. 91-87 and 94-198. 2. The Applicant shall submit a 24" by 36" 1041 site plan to the Community Development Department for approval and recording, prior to submission of any building permit applications. The site plan shall also be submitted in digital format for integration into the County's GIS system. The site plan shall comply with the provisions of Section 5-70-040 of the Land Use Code. 3. Prior to issuance of any permits and within a reasonable amount of time, the Applicant shall: A. Pay $1,560 (8 hours at $185/hour) to the Community Development Department to satisfy the time spent inspecting and responding to the Code violations. B. Submit a financial security in an amount and form acceptable to the County Attorney's Office for remediation of the existing violation. If the site is not developed in accordance with the development approval and the violation remedied within 24 months of the date of this approval, the BOCC may use the security to remediate the violation on the property This does not limit the BOCC from choosing other additional remedies to address this or other violations of the Code. 4. Prior to submittal of any building permits, the Applicant shall: A. Obtain an access permit from the County Engineer to extend the driveway to the residence and to construct a portion of the required fire turnaround, if necessary. B. Submit documentation that a fire hydrant was installed as part of the excavation for the driveway, as required. If a hydrant is not in place, the Applicant shall install a hydrant prior to issuance of any building permits. C. Provide documentation that the proposed residence complies with the recommendations made in the following reports: Dr. Nicholas Lampiris' letter of March 21, 1990, Chen 111111 11111 111111 IIIII Mill III 11111 IIII IIII Resolution No.99-14 438010 11/24/1999 12:09P RESOLUTI DAVIS SILVI Page 3 3 of 20 R 0.00 D 0.00 N 0 00 PITKIN COUNTY CO Northern's letter of April 18, 1990, Dr. Arthur Mears' letter of August 2, 1990 and report dated September 1990, Schmueser Gordon Meyer's report of September 25, 1990, and Design Structures' letter of October 15, 1990 (attached as Exhibits B-F). D. Submit a drainage and erosion control plan for review and approval by the County Engineer. The plan shall address means of controlling drainage and erosion during as well as following construction. The Applicant shall comply with the recommendations made by Schmueser Gordon Meyer in the "Gordon Miller Residence Drainage Report" dated September 25, 1990 (attached as Exhibit E). E. Submit a revegetation plan for review and approval by Land Management. The plan shall include an estimate of the cost of the revegetation (labor and plants). F. Submit an improvements agreement to address erosion, rockfall and drainage issues associated with the proposed access, excavation and construction stages of the development. The improvements agreement shall be reviewed and approved by the County Attorney, County Engineer and Community Development Director. G. Obtain Board of Adjustment approval for necessary setback variances. H. File a fireplace/woodstove permit with the Community Development Department. I. Submit a plan depicting the design and location for the required avalanche hazard warning signs, for review and approval by the Zoning Officer. J. Submit documentation that the property will be served by the City of Aspen Water Department. K. Submit documentation that the property will be served by the Aspen Consolidated Sanitation District. L. Submit a fugitive dust control plan for review and approval by the Environmental Health Department. The Applicant shall ensure that mud and dirt is not carried out onto surrounding roads by vehicle traffic from the site during construction. M. Demonstrate proof of insurance to protect neighboring properties from potential water flow and rockfall damage during construction of the residence to the satisfaction of the County Attorney. 5. Prior to issuance of any building permits, the Applicant shall: A. Post avalanche hazard warning signs along the driveway, as approved by the Zoning Officer. B. Submit financial security in a form acceptable to the County Attorney to ensure the successful revegetation of the property pursuant to the approved Revegetation Plan. Land Management shall specify the required amount of the financial security. The financial security shall be held for a minimum of one full growing season after the revegetation is completed, unless Land Management specifies a longer term. C. Submit financial security in a form acceptable to the County Attorney to ensure compliance with the improvements agreement. The County Engineer and Community Development Director shall specify the required amount of the financial security. 6. All areas disturbed by construction shall be revegetated to limit water consumption and additional runoff within one growing season of project completion. 7. No development activity, including grading, landscaping, and vegetation removal or disturbance shall occur outside the building envelope, with the exception of driveway and utility extension and maintenance and the performance of wildfire mitigation required as part of this approval. Native Resolution No. 99-11,(P Page 4 11E11 11111 111111 11111 111111 11111 11111 III IIIII 1111 438010 11/24/1999 12:09P RESOLUTI DAVIS SILVI 4 of 20 R 0.00 D 0 00 N 0.00 PITKIN COUNTY CO vegetation shall be maintained outside the building envelope (except for actions necessary to comply with the required wildfire mitigation). 8. No expansion of the approved square footage of the residence shall be permitted in the future. Development on the property is limited to a 5,930 square foot residence, all inclusive, and a 750 square foot garage. 9. The Applicant shall install an automatic fire sprinkler system in the residence, and shall comply with the codes and requirements of the Aspen Fire Protection District, including provision of an adequate fire turnaround and installation of a fire hydrant. 10. The Applicant shall comply with the following landscaping and wildfire defensible space mitigation standards to the satisfaction of the Colorado State Forest Service, prior to issuance of a Certificate of Occupancy for the residence: A. Brush, debris, and non -ornamental vegetation shall be removed within a minimum 10 foot perimeter around the structure. B. Vegetation shall be reduced to break up the vertical and horizontal continuity of the fuels a minimum of 45 feet uphill and to the sides of all structures. C. Spacing between clumps of brush and vegetation within the perimeter shall be a minimum of two times the height of the fuel. Maximum diameter of the clumps shall not exceed 10 feet. All measurements shall be from the edges of the crowns of the fuel. D. All branches from trees and brush within the perimeter shall be pruned to a height of 10 feet above the ground and ladder fuels from around trees and brush shall be removed. E. Tree crown separation within the perimeter shall have a minimum of 10 feet between the edges of the crowns. F. All branches which extend over the roof eaves shall be trimmed and all branches within 15 feet of the chimneys shall be removed. G. The density of fuels within a 100 foot perimeter of all structures shall be reduced. H. All deadfall within the 100 foot perimeter shall be removed. I. Low vegetation shall be maintained within a 10 foot perimeter around all structures. J. The Applicant shall be responsible for the continued maintenance of the defensible space vegetation requirements. 11. The Applicant shall comply with the following additional wildfire mitigation standards: A. An exterior sprinkler system shall be installed. B. Roofs shall have a Class A, non-combustible roof system. Wood shake/shingle roof coverings and flat roofs (up to a 3:12 pitch) are prohibited in all wildfire hazard areas. C. Vents shall be screened with corrosive resistant wire mesh with mesh 14 inch maximum. D. Roofs and gutters shall be kept clear of debris. E. Yards shall be kept clear of all litter, slash, and flammable debris. F. All flammable materials shall be stored on a parallel contour a minimum of 15 feet away from any structure. G. Weeds and grasses within the 10 foot perimeter shall be maintained to a height not more than 6 inches. H. Firewood/wood piles shall be stacked on a parallel contour a minimum of 15 feet away from the structure. I. Swimming pools shall be accessible to Fire Department vehicles. 111111 11111 111111 11111 111111 11111 11111 III 11111 1111 1111 Resolution No. 99- )74 438010 11/24/1999 12:09P RESOLUTI DAVIS SILVI Pages 5 of 20 R 0.00 D 0 00 N 0.00 PITKIN COUNTY CO J. Fences shall be kept clear of brush and debris. K. Wood fences shall not connect to the structure. L. Any outbuildings or additional structures shall adhere to the same standards as structures. M. Fuel tanks shall be installed underground with an approved container. N. Propane tanks shall be installed according to NFPA 48 standards and on a contour away from the structure with standard defensible space vegetation mitigation around anyabove- ground tank. Any wood enclosure around the tank shall be constructed with materials approved for 2 hour fire -resistive construction on the exterior side of the walls. O. Each structure shall have a minimum of one 10 pound approved ABC fire extinguisher placed in a visible and accessible location. P. Addresses shall be clearly marked with 2 inch non-combustible letters and shall be clearly visible at the primary point of access from the public or common access road and installed on a non-combustible post. Q. All utility lines shall be buried within the driveway or the utility easement. 12. The Applicant shall comply with the following 3ructural design and construction options: A. Projections (Heat Traps): 1) Projections at the roof line (which include but are not limited to eaves, cornices, soffits and roofs over open decks) shall be sheathed with materials approved for 1 hour fire -resistive construction. a) For projections below the roof line (including, but not limited to, exterior balconies, decks, porches, cantilevered floor projections, and bay windows, which extend over a flat or slopes surface) the open space between grade and the underside of projections below the roof line shall be enclosed by solid, vertical walls. These walls shall be constructed with materials approved for 1 hour fire -resistive construction on the exterior side of the wall and shall extend from the top of grade to the underside of the floor decking or walls of the projection. b) An alternative construction method for such projections would require use of noncombustible building materials, or heavy timber or log wall construction, if the underside of the projecting portion is covered with materials approved for one hour fire resistive construction and if there are no inside angles of less than 75 degrees. Areas below such projections shall be void of vegetative or other combustible materials. These areas below projections shall be protected from accumulation of vegetative materials by placement of a vegetative barrier covered with rocks or gravel or by coverage with concrete or stone. There shall be no storage of combustible materials under projections. The walls underneath projections shall be constructed with materials approved for 1 hour fire -resistive construction on the exterior side of the wall. Window openings in walls below projections shall be tempered glass. Doors shall be noncombustible or 1 3/4" solid wood. B. Windows and Glass: Glazed openings shall be provided with close -able, solid, exterior non-flammable shutters or shall be tempered glass. Resolution No. 99- ) Page 6 IIIIII11111 ������ (111111111111111IBM 11111 IIII IIII 438010 11/24/1999 12:09P RESOLUTI DAVIS SILVI 8 of 20 R 0.00 D 0.00 N 0.00 PITKIN COUNTY CO C. Exterior Walls and Siding: Siding and exterior wall construction shall have a minimum 1 hour fire -resistive rating ground level to roof line. Exterior doors shall be noncombustible or 1 3/4" solid wood. D. Foundations: Foundations, skirting and crawl space openings shall be fully enclosed and constructed with materials approved for 1 hour fire -resistive construction on the exterior side of the walls and shall extend from the top of grade to the underside of the floor decking or walls. E. Stilt Construction: The underside of decks and structures with stilt foundations shall be fully enclosed and constructed with materials approved for 1 hour fire -resistive construction on the exterior side of the walls and shall extend from the top of grade to the underside of the floor decking or walls. 13. All trash/garbage shall be contained in approved bear proof garbage containers. 14. The Applicant shall comply with the following standards for development within avalanche hazard areas: A. The foundation shall be designed by a certified engineer. B. Structural avalanche defenses shall be designed by a certified engineer to withstand avalanche impact forces. C. The owner shall bear the costs of any avalanche control meaures that may be required to mitigate the hazard. 15. The Applicant shall comply with the following standards for development on slopes of greater than 15%: A. Adequate mechanical support shall be provided for cut slopes. B. Adding water which may decrease slope stability shall be avoided. C. Adding weight to the top of the slope shall be avoided. D. Disturbed slopes must be contoured so that they can be revegetated. E. Steepening of existing slopes shall be avoided. F. Confine cuts, fills, grading and excavation to the minimum area needed for construction. 16. The exterior of the residence shall be finished in earth tones, which blend with the colors of the natural surrounding environment. Roof materials, gutters, downspouts, flashing, etc. shall be non - reflective and of earthtone colors. 17. Any exterior lighting on the residence shall be down -lighting and shall comply with the Code regulations in effect at the time of building permit issuance. Landscape and driveway lighting shall be prohibited. 18. If mine waste, waste rock or mine dumps are encountered during excavation of the property, the Applicant shall contact the Environmental Health Department. 19. For any free market residential structure of 5,000 gross square feet or greater, the Applicant shall comply with Section 4.01.01(B) of the Pitkin County Road Management and Maintenance Plan, 1111111111111111111111111111111111111111111111111111111 Resolution No. 99- / p 4o 438010 11/24/1989 12:09P RESOLUTI DAVIS SILVI Page7 7 of 20 R 0.00 D 0 00 N 0.00 PITKIN COUNTY CO which requires the Applicant to provide construction trip and residential trip generation studies. The Applicant shall comply with this provision as it is in effect at the time of building permit issuance to the satisfaction of the County Engineer. 20. The Applicant shall adhere to all material representations made in the application and in the public meetings. 21. The vested rights for this approval shall expire on October 27, 2002. APPROVED AND ADOPTED on the 27th day of October, 1999. PUBLISHED AFTER,,IDOPTION FOR VESTED REAL PROPERTY RIGHTS in the Aspen Times Weekly on thee/day of /VD l/ , 1999. ATTEST: yneIR Dean, Clerk to the BOCC APPROVED AS TO CONTENT: fi2WA 19 // 9. 99 Cindy Houben Community Development Director PID #2737-183-00-001 Exhibits A. Legal Description B. Nicholas Lampiris leter dated 3/21/90 C. Chen Northern's letter dated 4/18/90 D. Arthur Mears' letter dated 8/3/90 E. Arthur Mears' report dated 9/90 F. Schmueser Gordon Meyer's report dated 9/25/90 G. Design Structure's letter dated 9/25/90 BOARD OF COUNTY COMMISSIONERS, PITKIN COUNTY, COLORADO APPROVED AS TO FORM: John Ely Coun Attorney IIIIII IIIII Bill IIIII Ell IIIII III lilt Ill Iil l 438010 11/24/1999 12:09P RESOLUTI DAVIS SILVI 8 of 20 R 0.00 D 0 00 N 0.00 PITKIN COUNTY CO Exhibit "A" 4: 9f-/p- Legal Description: The Newfoundland Lode Mining Claim, M.S. 5190; excluding that portion of Newfoundland M.S. 5190 ouverlapping Hoag Subdivision, City of Aspen, Colorado, Lot 3. Starting at point #3, S 04 degrees 49'48" W 227.9 feet, - thence N 55 degrees 48'50".W 33.54 feet; thence N 65 degrees 31'10" W 37.97 feet; to rebar and plastic cap #9184 leaving line N 59 degrees 54' E 134.21 feet. k: f? •.Nicnotas Lampins, rn.u. CONSULTING G£OLOG7st 0793 VALLEY ROAD CARBONDALE. COLORADO 81673 p031963.3603 (7t moues) Jahn R. Wedum 616 East Hyman, Suite 102 Aspen CO 81611 RE: Newfoundland Claim Dear Randy: Exhibit B I have completed my geologic investigation for purposes of House Bill 1041 of the building site on the Newfoundland.. Mining Claim on the north -facing slope of Aspen Mountain..:•, above Ute Avenue as shown on the accompanying map. This is along the southern edge of the Town of Aspen within the Aspen 7 1/2 minute quadrangle, Pitkin County, Colorado. There is a proposed driveway to another homesite beyond the 'proposed site which is on a steep, conifer -covered hillside. There is no bench or.other break'in slope near the site and. the cnly other feature of note is an old portal into the mountainside which can be seen about two hundred feet east of the building site and below it. The geology of the site consists of a thin veneer of colluvial deposits containing angular blocks of limestone, sandstone and some granitic rocks. The matrix is mostly silty sand. This surficial deposit has been mapped by Bruce Bryant, 1971, as a talus deposit but I believe that the tern colluvium is mare accurate at this location. The underlying bedrock.ceuld not be determined because of lack of nearby outcrops, but is probably the Cambrian ace Sawatch Quartzite or one of the Lower Paleozoic carbonate units. Because of the steep attitude of bedrock units in t`is area and the faulting present, the bedrock could even be the Precambrian age quartz manzonite. At'.any rate, the appearance of the rocks within the colluvium indicates that the'bedrock is near surface. Snow sliding and minor rock fal.i is a possibility cn this property but there are two well established chutes on either side of the site which should contain most of these hazardous events. These paths can be well seen and their relationship,. to the site evaluated from across the valley in the Smuggler area. 11111111111111111111111111111111 IIIII III IIIII Ill It 438010 11/24/1999 12:09P RESOLUTI DAVIS SILVI 9 of 20 R 0.00 D 0 00 N 0.00 PITKIN COUNTY CO 1111111111111111111111111111111111 11111111111111111 1111 438010 11/24/199S 12:09P RESOLUTI DAVIS SILVI 10 of 20 R 0 00 0 0.00 N 0.00 PITKIN COUNTY CO k : 99-04 This, in addition to the extensive tree cover above the Site, should minimize the potential hazard to the site; nevertheless, the rear foundation wall should be designed' to protrude at least six feet above finished grade and be without doors cr windows an this upslope-facing side of the home. It should be strong enough. to withstand farces of at least 200 pounds per square foot, or the equivalent if the building can be designed to be prow -shaped up the hilh, thereby reducing the:forces potentially affecting the proposed home. Slope stability is the most important consideration for this ' site because of the steepness. There is n., indication of -long term instability on this site. .The °pistol -butting" of .some trees is probably due to down hill snow pressure rather than instability of the.colluvium, but a factor of safety analysis is 'efinitely in order. The nearness of bedrock to the surface is a positive factor because presumably the foundation can be anchored to it. Positive drainage around the home will be important and natural vegetation not requiring watering is advised to further insure stability of the site. Obviously, soils' engineering will be an important aspect of this project. The faulting mapped in the area has been inactive for ' thousands of years with nn evidence in the field of recent. movement. The above -referenced portal trends well east of the site but subsurface maps of the area should be evaluated 'to' be sure there is no near -surface tunnel or stope directly under the site. I believe that water and waste disposal systems will be available from municipal sources. In order to prevent the possible accumulation of radon gas, adequate sub -floor ventilation should be provided ir, the construction of the home. If there are further quettions., please do not hesitate to contact me. Sincerely, 12-1.4 Nicholas Lampiris Consulting Geologist ,e : ff" /t6 1111111 Hill 1111111111I 1111111111111111 III 01111 III 1111 438010 11/24/1999 12:09P RESOLUTI DAVIS SILVI 11 of 20 R 0 00 0 0.00 N 0.00 PITKIN COUNTY CO Exhibit C --.Apr`! 18, 1990 Randy Wader 616 East Hyman, Suite 102 Aspen CO 81611-1981 . Subject: Review cf Soil and Geologic Corziitions, Newfoundland Parcel, Pitkin County, Colorado.. _ Job No. 4 319 90 As requested, we are .prov'.ding cuimrsrts regarding the soil and geologic contiticaz at the subject :Ate based on cur experience in the area. Chen Northern previously conducted geotes±nical studies en the adjacent let 2, Hoag Subdivision, for feasibility and foundation design of a prcposed residence and reported our fitdirgs under Jai No. 4 275 89. Aresidence is proposed at the lower end of the Newfa:rrdlarii Par which will use a carmen driveway with int 3. The hillside terrain is consistent in the a -ea and we expect the subsoil and geologic conditions are also similar to those identified cn Lot 3. The proposed building site lies within a potential avalanche zone and could be impacted by debris flaws. • Eased cn our experience in the area, development on the property appears feasible from a geotec± nical viewpoint. There is a risk of construction induced slope instability. A design level geotec'.^.nical study should be conducted to &dress the site stability, foundation, drainage and grading for the proposed bui .dim. The site should be evaluated for avalanche and debris flow risk andany monied mitigation. We are available to conduct the subsoil study at ycur request. If you have any questions or if we can be of further assistance, ploan let us know. Sincerely, CHE N-NORTHERN, LNC. Steven L. Pawlak, P.E. SIP/ec ♦acne, dnc (H n4 Taadcon:m —/n Exhibit D ARTHUR 1. MEARS, P.E., INC. Nanrtni Hazards Canuiuu<u 222 Lag Cothk A... G...:.-. Colo..& 81230 303-641.3214 August 3, 1990 Mr. John Wedum Wedum Design and Development 616 E. Hyman Ave. Aspen, CO 81612 Dear Mr. Wedum: At your request, I conducted a site inspection of the lot identified as „Newfoundland MS 5190' above 'Jte Avenue on August 2, 1990. The purpose of this site inspect n was to evaluate the potential for snow avalanches at the build_ag site and to consider the feasibility of avalanche mitigation. AVALANCHE -HAZARD POTENTIAL Inspection of the terrain and vegetation at and above the building site indicates the proposed construction area is within range of sma:3 avalanches that fl a through the trees and can impact the proposed building. Charazteristic avalanche damage near the site consists of bent and deformed main stems of fir trees, broken trees, and vegetative debris align,.1 downslope. Small avalanches may reach the site at 10-year return periods, on the average. However, even during design -:magnitude ("lo0-year") avalanche conditions, avalanches will be small and will not possess great destructive energy. AVALANCHE MITIGATION Avalanche mitigation at this site is feasible and can be achieved through "direct protection" of t'le building. This would be accomplished by reinforcing the uphill wall/roof system for avalanche static and dynamic loads. The magnitudes, directions,. and areas affected by these loads cannot be determined at the present time. Loading characteristics can be determined given final architectural details about building size, shape, and orientation. The building should be designed to eliminate or minimize activity on the uphill side. Reinforcement of the building for avalanche loads would stop the avalanche at the uphill side of the building and therefore would reduce the hazard on the driveways below the site which are now exposed to avalanches. .j�ncerely, ( .O.(4 4. \ 11ee Arthur I. Mears, P.E. Avalanche -control emit eer IIIIII IIIII IIIIII IIIII IIIIII IIII"II'I III "I'll III IIII 438010 11/24/1999 12:09P RESOLUTI DAVIS SILVI 12 of 20 R 0.00 D 0 00 N 0 00 PITKIN COUNTY CO it: 99-i*b Exhibit E IIIIII 11111 IIIIII 1111111111 11111 11111III 111111 III IIII 438010 11/24/1999 12:09P RESOLUTI DAVIS SILVI 13 of 20 R 0 00 D 0.00 N 0.00 PITKIN COUNTY CO '.SNOW—AfALANCEE LOADING ANALYSIS PROPOSED BUILDING AT "NEWFOUNDLAND MS 5190" UTE AVENUE, NEAR ASPEN, COLORADO Prepared For Mr. John Wedum Prepared By Arthur I. Mears, P.E., Inc. Gunnison, Colorado September, 1990 R:99-in. OBJECT=VES AND LISITATICNS This analysis'cf snow -avalanche loads was requested by Mr. John Wedum of Wedum Design and Development. The proposed building analyzed in this report is located on the lot identified as "Newfoundland MS 5190," above U':e Avenue, near Aspen, Colorado. The objectives of this study are: a. Computation of design -magnitude ("100-year") avalanche velocities and pressure potentials at the building site; b. Calculation of forces on exposed building surfaces at the above -described lot; c. Description of the avalanche loads and effects of the avalanche on the structure; and d. Description of the change in avalanche hazard resu.'ting from the proposed project. . This analysis considers snow avalanches and snow -avalanche loads only. Other geological and/or meteorological process and the interaction of such processes on the proposed structure have not been considered. In particular, design snow loads which usually are applied in design at this location must be added to the avalanche loads given here. The loads computed depend on building location, size, shape, and orientation as specified in the John Wedum drawings which were drawn on September 18, 1990. Significant changes tc these plans may invalidate the loads given in this report. 2 DESIGN -AVALANCHE CHARACTERISTICS The design avalanche, or event with an estimated return period of 100 years (a constant 1% annual probability), will begin on the steep, northeast -facing slope approximately 400 feet above the building site, at an elevation of 8,500 feet. Although this slope supports a continuous ccnifer forest, the spacing of trees in the forest is not sufficiently close to anchor the snowpack prevent avalanche release. Damage to t ees above and at the site indicates avalanches have occurred in the past. The design avalanche was computed by application of statistical and dynamic mciels as described in Mears (1989) and Mears (in prep.). The design -avalanche parameters used in load computations are: velocity = 11.0 m/s (25 mph);•flow density = 400 kg/m3 (25 lbs/ft3); flow depth = 1.0 m (3.3 ft). Soil and vegetative debris, including tree trunks, may be entrained in the avalanche debris and complicate loading characteristics, as discussed 4.n Section 3. IIIIII IIIII IIIIII IIIII IIIIII IIIII IIIII III IIIIII III IIII 438010 11/24/1988 12:08P RESOLUTI DAVIS SILVI 14 of 20 R 0.00 D 0 00 N 0.00 PITKIN COUNTY CO X: 99-'fl 3 AVALANCL LOADS AND LOAaDING c3IRACTISSTICS Building surfaces exposed to avalanches and receiving avalanche loads are ;hown as surfaces "A" through "Y" on Figure 1. goof surfaces "A," "B." and "0" receive impact (deflection) loads as the avalanche flaw direction is changed by the roof and receive depositional loads as the compressed avalanche debris is deposited on the roof. The deflection and depositional loads are not simultaneous, however. The design case on these surfaces will be a static depositional load which is trapezoidal in cross section as shown on Figure 2. This load may persist for the entire snow season, a period which may extend from December through April at this location. The "elevator wedge." surfaces "V" and "W" are vertical surfaces that receive avalanche impact loads. As shown in Figure 2, unit loads on the elevator wedge have been resolved into 3 components which are normal (P3), horizontal shear (P4), and vertical shear (Ps). These are impact loads which will increase over the entire 10-foot height cf the wedge from zero tb the maximum specified in Figure 2 in 0.2-to-0.4 seconds. Because they increase quickly, the strains produced by these loads may be greater than those resulting from an equivalent static load of equal magnitude, a fact that should be considered by the structural engineer in final design. The guide walls "X" and "Y" are intended to protect the sloping glass surface "C," as the avalanche expands laterally on the roof. As shown on Figure 2, the guide walls receive a uniform, horizontal impact load (P6), as specified. These horizontal loads are assumed to be constant to the top cf the guide walls which decrease in height in the downhill direction (north). These loads also increase from zero to maximum in 0.2-to-0.4 seconds and probably also must be treated as impact loads because they may produce strains in excess of those resulting from an equivalent static load. All of the impact loads specified in this report have been computed ass.ning the avalanche is a homogeneous "fluid" of a density of 400 kg/m3 (25 lbs/ft3) at the instant of impact. In fact, the avalanche will probably contain small rocks, tree trunks, and other solid material which can produce point loads that may exceed the average loads given in this report. However, the loading surface areas for these point loads will be small (less than 1 ft2), therefore would not precipitate general structural failure. They may, however, produce localized damage to the surface receiving impact, a fact that should be considered in design and maintenance. 1 IIIIN 11111 111111 11111 111111 11111 11111 III 111111 III 1111 438010 11/24/1999 12:09P RESOLUTI DAVIS SILVI 15 of 20 R 0.00 D 0 00 N 0 00 PITKIN COUNTY CO R : 99-ir4 4 CHANGE 2:7 AVALANCHE HAZARD In general avalanche "hazard" will increase in proportion to the number of persons exposed to the avalanche process. The proposed project, similar to other projects planned and/or built in avalanche areas throughout the United States, Canada, and Europe, will draw an increased number of persons into avalanche terrain, therefore may increase the overall hazard. The persons one wishes to protect simply may not be in the specially -design building when the avalanche occurs. They would be exposed to avalanches if they were above the building or in the forest on the sides of the building. However, the proposed project does not plan exposed living areas or decks in the avalanche areas. Furthermore, this project will stop avalanches before .they reach the access road. Therefore the exposure to avalanches below the building and on the road will be reduced as a result of this project. • Because there may be a small increase in overall avalanche hazard simply because more people may be in avalanche terrain after building construction, this increase can be minimized if residents educate themselves about the avalanche'phenomena and heed all official avalanche warnings and advisories. Such self education is recommended for all those who plan to live in avalanche terrain. • Report submitted by, E Arthur I. Mears, P.E. Avalanche -control engineer 1111111111111111111111111111111111111111111111111111111 438010 11/24/1999 12:09P RESOLUTI DAVIS SILVI 18 of 20 R 0 00 D 0.00 N 0.00 PITKIN COUNTY CO Roof rfaces A. ?. and D P Q:41 /8b 7-1 = 300 fzs/ft` 15ft ..� P2 = 150 lbt (Static loads) Surfaces V and W (elevator wedre) P3 = 23o lbs/ft2 P4 = 130 lbs/ft2 P5 = 130 lbs/ft2 (P3, P. and'P5 are impact loads) P5 is vertical (upward) shear acting on surfaces V and W. L Guide Walls X and Y t { c P P6 = 100 lbs/ft2 P6 is a uniform, impact load acting td the upper edge of the Guide walls, which are variable in height. FIGURE 2. Directions and magnitudes of avalanche loads on,.'arious exposed building surfaces. These avalanche loads are in addition to other loads (including snow loads) usually considered in design at this location. See text for limitations and additional discussion. �` V 'CONSULTING £NGiN£EP.S L /°TORSI is 01-4 - > —JN 6-1 Paz ENO =.,o — a Paz 8-1 —n n �O- m neinW61 d'm O.Z —mm —N� CIc ▪ 61 � • e 0 c.l Cr wm —sN _.. ,. CD o de• co September 25, 1990 Exhibit F Mr. Randy Wedum 616 East Hyman Avenue, Suite 102 Aspen, Co. 81611 RE: Gordan Killer Residence Drainaze Report Dear Randy: This letter is in follow-up to•your request for a drainage report for the Cordon'Hiller Property, also known as the Newfoundland H.S. 5190 Mining Claim, off of Ute Avenue in Aspen. This report is based on our discussion of September 19, 1990, the schematic building plans which you provided to me at that time, a site visit on September 24, 199c and the review of a drainage plan for the Hoag Snbdivision, Lot 3, located Just to the west of. this building site. It is my understanding that this drainage report is being requested in order to verify that off -site drainage -will not impact the proposed structure and -that drainage passing through the building site can be directed and controlled 1: an appropriate !I? -Ire:. Based predominantly on my field inspection'of September 24, 1990, I do not anticipate that off -site drainage represents a significant hazard to the proposed building envelope. During my site inspection I noted that there are no on -site gullies which would appear to direct a significant storm flow into the building area. The area is generally well vegetated including numerous large fir trees and gives no evidence of even seasonal drainage'lmpacts. In addition, as noted in Nick Lampiris's letter to you of March 21, 1990, there exists two large chutes, one on either side of the building site, which would tend to contain the more significant snowelide and rockfall events. As a result, drainage which may impact tie Miller .Parcel will generally tend to be sheet flow from the areas immediately above the site. The storm drainage plan prepared for the Hoag Subdivision, Lot 3, by Tim Beck of High Country Engineering, provides several applicable conditions for a site nearly identical to the Hiller Property. comparable calculations for upslope drainage area, soil type, and run-off coefficients indicate that drainage impacting the Miller Residence should be in the range of 0.7 of a cubic foot per second (cfs) in a 100 year storm event. Because the upslope area is well vegetated and topography would not encourage a concentrated flow impacting the site, a debris flow event is tighly unlikely. For purposes of design, however, I would be inclined tc utilize a debris flo•:. bulking factor of 50% resulting in a total 100 year storm flow of 1.05 cfs. Even with these conservative assumptions, a 1.05 cfs flow does not represent a significant concern. 1512 Grand Avenue, Suite 212 • Glenwood Springs, Colorado 81601 • (303) 945-1004 99-/tl �' September 25, 1990 C, Mr. Randy Wed �o Page 2 Paz Y 1.4 an d Mitigation Recommendations SO- B 4/3 Generally speaking, desired mitigation of the potential storm run- d z off impacting this site comprises a series of wales that will S UM m direct the flow around the structure to the uphill aide of•the entry O EM N B drive. The proposed awale south of the uphill building wall, as m ahown on your plans delivered to me on September 9, 1990, is more N amde than adequate to intercept a 1 cfs flow. I would recommend that this m • swale•be continued around. the structure utilizing a triangular 0=1N m section 4 feet wide by 1 foot deep on both sides of the building, • This Swale should be revegetated utilizing erosion control matting,' " ▪ N topsoil and seeding with native plant types that would not interfere m o with storm flows through the Swale. min maim — a " As you had noted on the building plan, design•will entail retaining walls immediately above the road. I would suggest including a catct basin above the retaining walls on each side of the structure to intercept storm flows before they over -top the wall. Flows would be routed behind the wall and then through the bottom of the wall to the uphill side of the road. Along the uphill side of the road where the driveways would be crossing, I would recommend tte Dlacementof 18° diameter culvert crossings connecting to the borrow ditch on the uphill side of the road. These culvert sizes are Significantly larger than the flow would require but smaller culverts can be more easily plugged and rose a maintenance problem. As a final note, the borrow ditch on the uphill side of tte new roadway should be carried downslope as far as necessary to avoid Impacts to adjacent properties. Where appropriate an additional culvert crossing to the south side of Ute Avenue may be needed. I trust that this report will be adequate for County review purposes, feel free to contact me if I may provide further information or additional detail regarding design. Respectfully submitted, SCHMUESER GORDON MEYER, INC. Yay w rHammond, P.E. Principal -Aspen Office JH/ja90203 DESIGN � - .1 r Z um.wc S CC z 0 =wI— S - 5d _om ▪ 0 CCm MIMMI as 6/ — N -m mc um.�m vm N� .\e Go INN ass• o o amm • N STRUCTURES, INC. ,2•'99/K 25 September 1990 Wedum Design Developmcnt 616 E. Hyman Suite 102 Aspen, Colorado 81611 • Attn: Randy Wedum - Re: Gordon Miller Building Envelope • Ger. tlemer.: • WRiam M. Newell. RE hrdd•rn Exhibit G We have reviewed the proposed house to be located on the Newfoundland Parcel, Aspen, Colorado. During our review and design of structural framing we reviewed the requirements for soil conditions and avalanche and debris flow agai:.st the building. We have designed concrete foundation/retaining walls to resist the lateral forces imposed by the slope of the soil against the building and the avalanche and det:is flow forces. We have provided drawings showing the required reinforcement of the proposed walls. We have also designed the roof of the house to resist a 300 psf live load as required for avalanche. We feel that constructed, noted above. the proposed building is capable of being and that it will withstand the imposed loads Please contact us if you have any questions or comments. Sincerely, DESIGN STRUCTURES, INC. William H. Newell, P.E. President ' WILLIAM H. NEWELL 1660 Sevrnlernll• Sure! • Suite 200 • Deriver, Colorado R0202 • 13031 623-4927 • FAX (3031 62345