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Home My WebLink AboutGeotechnical Engineering StudyGEOTECHNICAL ENGINEERING STUDY PROPOSED FOUR SEASONS RESORT VAIL ROAD AND SOUTH FRONTAGE ROAD WEST VAIL, COLORADO JOB NO. 105 291 JUNE 22, 2005 PREPARED FOR: VAIL DEVELOPMENT, LLC ATTN: DOUGLAS G. HIPSKIND 50 SOUTH SIXTH STREET SUITE 1480 MINNEAPOLIS, MINNESOTA 55402 t TABLE OF CONTENTS PURPOSE AND SCOPE OF STUDY .............................................. .............................. - I - PROPOSED CONSTRUCTION ....................................................... .............................. - 1 - SITECONDITIONS ......................................................................... ............................... 2- FIELD EXPLORATION ................................................................... .............................. - 2- SUBSURFACE CONDITIONS ........................................................ .............................. - 3- ENGINEERING ANALYSIS ........................................................... ............................... 3 - DESIGN RECOMMENDATIONS ................................................... .............................. - 4- FOUNDATIONS........................................................................... ............................... 4- FOUNDATION AND RETAINING WALLS ............................................................. 5 - FLOORSLABS ............................................................................ ............................... 7- UNDERDRAIN SYSTEM ............................................................ .............................. - 7- SITEGRADING .........................................................................................................- SURFACEDRAINAGE ............................................................... ............................... 9- LIMITATIONS................................................................................. ............................... 9- FIGURE 1 - LOCATION OF EXPLORATORY BORINGS FIGURES 2 through 5 - LOGS OF EXPLORATORY BORINGS FIGURE 6 - LEGEND AND NOTES FIGURES 7 through 15 - GRADATION TEST RESULTS TABLE 1- SUMMARY OF LABORATORY TEST RESULTS TABLE 2 — SUMMARY OF GROUNDWATER LEVELS PURPOSE AND SCOPE OF STUDY This report presents the results of a subsoil study for the proposed Four Seasons Resort to be located at the southwest corner of Vail Road and South Frontage Road West, Vail, Colorado. The project site is shown on Figure 1. The purpose of the study was to develop recommendations for the foundation design. The study was conducted in accordance with our proposal for geotechnical engineering services to Vail Development, LLC dated April 5, 2005. A field exploration program consisting of exploratory borings was conducted to obtain information on the subsurface conditions. Samples of the subsoils obtained during the field exploration were tested in the laboratory to determine their classification and other engineering characteristics. The results of the field exploration and laboratory testing were analyzed to develop recommendations for foundation types, depths and allowable pressures for the proposed building foundation. This report summarizes the data obtained during this study and presents our conclusions, design recommendations and other geotechnical engineering considerations based on the proposed construction and the subsurface conditions encountered. PROPOSED CONSTRUCTION The above grade portion of the proposed building footprint will cover most of the property as shown on Figure 1. The proposed building will be multiple stories above ground with below ground parking located primarily below the north half of the building. The existing hotel and gas station facilities will be removed prior to the new construction. Ground floors will be slab -on- grade. Grading for the structure, particularly the below ground parking area, will be relatively extensive, with cut depth of roughly 30 to 40 feet. Temporary dewatering and excavation shoring will be required for the foundation construction. We assume moderate to relatively heavy foundation loadings carried by perimeter walls and interior columns. Job No. 105 291 tech I$ -2- If building loadings, location or grading plans change significantly from those described above, we should be notified to re- evaluate the recommendations contained in this report. SITE CONDITIONS The site is currently occupied by an existing hotel and gas station. These buildings and related facilities will be removed prior to the new construction. The property is bordered by Vail Road, South Frontage Road West and West Meadow Drive to the east, north and south, respectively. The ground surface is relatively flat and slightly irregular due to previous site grading and landscaping, generally with a gentle slope down to the south. There is about 20 feet of elevation difference across the property. The buildings are surrounded by asphalt and concrete pavement, and landscaped areas. FIELD EXPLORATION The field exploration for the project was conducted between April 25 and June 6, 2005. Eighteen exploratory borings were drilled at the locations shown on Figure 1 to evaluate the subsurface conditions. Boring 1 was advanced with 33/4 -inch I.D. hollow stem augers powered by a truck - mounted Longyear BK -51 HD drill rig. Borings 2 through 17 were advanced with 4 -inch diameter continuous flight augers powered by truck- mounted CME- 45B and Longyear BK -51HD drill rigs. Borings 2, 9 and 15 were advanced past initial auger refusal with 6 -inch diameter, rotary/percussion casing advancer (ODEX) powered by a truck - mounted CME -55 drill rig. Boring 18 was advanced the entire depth with the ODEX system. The borings were logged by representatives of Hepworth - Pawlak Geotechnical, Inc. Slotted PVC pipe, 1' /2 or 2 -inch diameter, was installed in Borings 1, 2, 3, 6, 9, 10, 12 to 16, and 18 for groundwater level monitoring. Samples of the subsoils were taken with I% inch and 2 inch I.D. spoon samplers. The samplers were 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 Job No. 105 291 c99tiech s -3- and the penetration resistance values are shown on the Logs of Exploratory Borings, Figures 2 through 5. The samples were returned to our laboratory for review by the project engineer and testing. SUBSURFACE CONDITIONS Graphic logs of the subsurface conditions encountered at the site are shown on Figures 2 through 5. The subsoils generally consist of about 3 to 11 feet of typically granular fill overlying relatively dense, stratified silty sand and gravel containing occasional zones of cobbles and boulders. Silty sand lenses, varying from 2 to 11 feet thick, were occasionally encountered in the borings. A shallow depth of topsoil was encountered above the fill in lawn areas at Borings 1, 9, 10, and 13 through 15. Asphalt or concrete pavement was encountered above the fill in the remaining borings, except at Boring 3. Drilling in the dense granular soils with hollow stem and solid flight auger equipment was difficult due to the cobbles and boulders and drilling refusal was encountered at relatively shallow depths in the deposit at Borings 4, 7, 8, 11 and 17. Laboratory testing performed on samples obtained from the borings included natural moisture content, gradation analyses and Atterberg limits. Results of gradation analyses performed on small diameter drive samples (minus 1'/2 inch fraction) of the coarse granular subsoils are shown on Figures 7 through 17. Atterberg limits tests indicate that the existing fill soils have low plasticity. The laboratory testing is summarized in Table 1. Groundwater was measured in the deeper borings between the depths of 20 and 31 feet. The subsoils above the water level were slightly moist to moist. A summary of the groundwater level measurements is presented on Table 2. ENGINEERING ANALYSIS The natural granular soils encountered below the existing fill are suitable for support of spread footings with moderate bearing capacity and relatively low settlement potential. Job No. 105 291 WJ s« -4- The proposed relatively deep cuts will tend to increase the risk of construction - induced slope instability. We expect that excavations for below grade areas will require shoring to maintain cut slope stability. Due to the extensive cuts, underpinning of nearby buildings or facilities may also be needed depending on the relative bearing elevations. The building foundation walls will need to be designed to resist appropriate lateral earth (backfill) pressures. The proposed lower level of the parking garage is near to below the existing groundwater level. Excavation dewatering will likely be needed for construction in the dry. An underdrain system should be provided to protect below grade areas of the building against groundwater level rise or the below grade area should be designed to resist buoyancy forces. DESIGN RECOMMENDATIONS FOUNDATIONS Considering the subsurface conditions encountered in the exploratory borings and the nature of the proposed construction, we recommend the building be founded with spread footings bearing on the natural granular soils. The design and construction criteria presented below should be observed for a spread footing foundation system. 1) Footings placed on the undisturbed natural granular soils should be designed for an allowable bearing pressure of 4,000 psf. Based on experience, we expect settlement of footings designed and constructed as discussed in this section will be about 1 inch and essentially occur during construction. We should conduct a settlement analysis when design foundation loads have been determined. 2) The footings should have a minimum width of 24 inches for continuous walls and isolated pads. 3) Exterior footings and footings beneath unheated areas should be provided with adequate soil cover above their bearing elevation for frost protection. Job No. 105 291 G4 � -5- Placement of foundations at least 48 inches below exterior grade is typically used in this area. 4) Continuous foundation walls should be reinforced top and bottom to span local anomalies such as by assuming an unsupported length of at least 12 feet. Foundation walls acting as retaining structures should also be designed to resist lateral earth pressures as discussed in the "Foundation and Retaining Walls" section of this report. 5) All existing fill, debris from prior site development, topsoil and any loose or disturbed soils should be removed and the footing bearing level extended down to the relatively dense natural granular soils. Silt and sand soils may need to be subexcavated and backfilled with compacted sand and gravel or with concrete. The exposed soils in footing areas should then be moisture treated and compacted. If water seepage is encountered, the footing areas should be dewatered before concrete placement. 6) A representative of the geotechnical engineer should observe all footing excavations prior to concrete placement to evaluate bearing conditions. 7) AN IOC seismic soil type of C can be assumed for the foundation placed in the relatively dense granular soils. FOUNDATION AND RETAINING WALLS Foundation walls and retaining structures up to about 12 feet tall which are laterally supported and can be expected to undergo only a slight amount of deflection should be designed for a lateral earth pressure computed on the basis of an equivalent fluid unit weight of at least 50 pcf for backfill consisting of the on -site granular soils. Cantilevered retaining structures up to about 12 feet which are separate from the building and can be expected to deflect sufficiently to mobilize the full active earth pressure condition should be designed for a lateral earth pressure computed on the basis of an equivalent fluid unit weight of at least 40 pcf for backfill consisting of the on -site granular soils. Foundation walls and retaining structures greater than 12 feet tall should be designed for a uniform lateral earth pressure in psf of 24 and 18 times the wall height in feet for the restrained Job No. 105 291 Gt M condition and active condition, respectively. Backfill should not contain debris, vegetation, topsoil or oversized rock. All foundation and retaining structures should be designed for appropriate hydrostatic and surcharge pressures such as adjacent footings, traffic, construction materials and equipment. The pressures recommended above assume drained conditions behind the walls and a horizontal backfill surface. The buildup of water behind a wall or an upward sloping backfill surface will increase the lateral pressure imposed on a foundation wall or retaining structure. An underdrain should be provided to prevent hydrostatic pressure buildup behind walls. Backfill should be placed in uniform lifts and compacted to at least 95% of the maximum standard Proctor density at a moisture content near optimum. Backfill in pavement and walkway areas should be compacted to at least 95% of the maximum standard Proctor density. Care should be taken not to overcompact the backfill or use large equipment near the wall, since this could cause excessive lateral pressure on the wall. Some settlement of deep foundation wall backfill should be expected, even if the material is placed correctly, and could result in distress to facilities constructed on the backfill. A higher compaction level of 98% of the standard Proctor density could be used to help reduce the settlement risk. We recommend granular soils for backfilling foundation walls and retaining structures because their use results in lower lateral earth pressures and the backfill will help the subsurface drainage. Subsurface drainage recommendations are discussed in more detail in the " Underdrain System" section of this report. Granular wall backfill should contain less than 15% passing the No. 200 sieve and have a maximum size of 6 inches. The lateral resistance of foundation or retaining wall footings will be a combination of the sliding resistance of the footing on the foundation materials and passive earth pressure against the side of the footing. Resistance to sliding at the bottoms of the footings can be calculated based on a coefficient of friction of 0.50. Passive pressure of compacted backfill against the sides of the footings can be calculated using an equivalent fluid unit Job No. 105 291 G99beCh -7- weight of 400 pcf for dry backfill and 250 pcf for submerged backfill conditions. The coefficient of friction and passive pressure values recommended above assume ultimate soil strength. Suitable factors of safety should be included in the design to limit the strain which will occur at the ultimate strength, particularly in the case of passive resistance. Fill placed against the sides of the footings to resist lateral loads should be compacted to at least 95% of the maximum standard Proctor density at a moisture content near optimum. FLOOR SLABS The natural on -site soils, exclusive of existing fill and topsoil, are suitable to support lightly loaded slab -on -grade construction. To reduce the effects of some differential movement, floor slabs should be separated from all bearing walls and columns with expansion joints which allow unrestrained vertical movement. Floor slab control joints should be used to reduce damage due to shrinkage cracking. The requirements for joint spacing and slab reinforcement should be established by the designer based on experience and the intended slab use. A minimum 4 inch layer of free - draining gravel should be placed beneath lower parking level slabs to facilitate drainage. This material should consist of minus 2 inch aggregate with at least 50% retained on the No. 4 sieve and less than 2% passing the No. 200 sieve. All fill materials for support of floor slabs should be compacted to at least 95% of maximum standard Proctor density at a moisture content near optimum. Required fill can consist of the on -site granular soils devoid of debris, vegetation, topsoil and oversized rock. UNDERDRAIN SYSTEM Groundwater was encountered near the expected depths of the excavation and it has been our experience in the area that local perched groundwater can develop during times of heavy precipitation or seasonal runoff. Frozen ground during spring runoff can create a perched condition. We recommend below -grade construction, such as retaining walls and Job No. 105 291 -8- the below ground parking area, be protected from wetting and hydrostatic pressure buildup by an underdrain system. As an alternative, the structure could be designed to be watertight and resist potential hydrostatic pressure uplift. The underdrain should be comprehensive and consist of an underslab free - draining gravel layer that is connected to perimeter and interior lateral drains. The perimeter drain should consist of drainpipe placed in the bottom of the wall backfill 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 I% to a suitable gravity outlet. The interior lateral drains should consist of a perforated pipe placed in gravel filled trenches on about 20 to 25 foot centers that connects to the underslab gravel and sloped to a minimum ' /2% to the perimeter drain system. The pipe invert of the perimeter and interior lateral drains should be at least 2 feet below the lower finished floor level. Free - draining granular material used in the underdrain system should contain less than 2% passing the No. 200 sieve, less than 50% passing the No. 4 sieve and have a maximum size of 2 inches. The drain gravel backfill should be at least Met deep. A drainage mat should be placed against the backside of the foundation wall that connects to the perimeter drain gravel. A sump and pump system should be provided to remove the drain water as needed. SITE GRADING Excavation for the below grade parking area is proposed to be relatively extensive and there is a risk of construction - induced slope instability. Temporary cut slopes steeper than about 1'/2 horizontal to 1 vertical should be supported with shoring or stabilized. Possible methods of shoring consist of soldier pile and timber lagging, soil nailing and micro piles. Soil nailing and tiebacks should be feasible where there is adequate distance or easement back from the face of the excavation wall for nail or anchor embedment of the reinforcement. The subsoils are stratified alluvial deposits and layers of higher silt fraction could limit the effectiveness of the nails or anchors. The excavation shoring should be designed and built by qualified engineers and contractors that specialize in the selected methods and that are familiar with the subsurface conditions in the area. For Job No. 105 291 preliminary design, the natural granular soils can be assumed to have an internal friction angle of 34 degrees, a cohesion of 0 psf and a moist unit weight of 130 pcf. We should review the proposed grading and excavation shoring plans prior to construction. SURFACE DRAINAGE The following drainage precautions should be observed during construction and maintained at all times after the building has been completed: 1) Inundation of the foundation excavations and underslab areas should be avoided during construction. 2) Exterior backfill should be adjusted to near optimum moisture and compacted to at least 95% of the maximum standard Proctor density in pavement and slab areas and to at least 90% of the maximum standard Proctor density in landscape areas. 3) The ground surface surrounding the exterior of the building should be sloped to drain away from the foundation in all directions. We recommend a minimum slope of 6 inches in the first 10 feet in unpaved areas and a minimum slope of 3 inches in the first 10 feet in paved areas. Free - draining wall backfill should be capped with about 2 feet of finer grained soils to reduce surface water infiltration. 4) Roof downspouts and drains should discharge well beyond the limits of all backfill. LIMITATIONS This study has been conducted in accordance with generally accepted geotechnical engineering principles and practices in this area at this time. We make no warranty either express or implied. The conclusions and recommendations submitted in this report are based upon the data obtained from the exploratory borings drilled at the locations indicated 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 the future. If the client is Job No. 105 291 G 9teCh 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 described 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 design purposes. We are not responsible for technical interpretations by others of our information. As the project evolves, we should provide continued consultation and field services during construction to review and monitor the implementation of our recommendations, and to verify that the recommendations have been appropriately interpreted. 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. Trevor L. Knell, P.E. Reviewed by: Steven L. Pawlak, P.E. TLK/ksw cc: Alpine Engineering — Attn: Jim McNeil The John Hardy Group — Attn: Peter Speth Job No. 105 291 BORING 6 / BORING 1 •i X PROPOSED ABOVE— GROUND % BUILDING FOOTPRINT BORING 18 r� i Y j , jjj � • x, 1/j $g � BORIMIG 17 GORING 136RING 2 £f r �/ • e • i; BORING 15 a� - • �'O._- • BORING 7 E iij ■■ EXISTING `� p HOTEL e � � .. • vpi BORING 11 BORING 3 t BORING 8' BORING 9 BORING 16 —� _ 'r �' BONG 4 i" µ EXISTING GAS;, g STATION l f BORING 10 w ORING 5 k • VAIL ROAD1` Note: Site plan provided by Alpine Engineering, Inc. Not for construction, for boring APPROXIMATE SCALE: location reference only. 1" = 60 105 291 -A;t eeh LOCATION OF EXPLORATORY BORINGS Figure 1 HEPWORTH-PAWLAK GEOTECHNICAI BORING 6 BORING 7 BORING 8 BORING 9 BORING 10 ELEV. =8160' ELEV.= 8165.5' ELEV. =8168' ELEV. =8165' ELEV= 8167.5' 8170 LL- 8170 17/6,6/6 (4) 0 >> (4) 8130 (4) w 12/12 16/12 +4 =30 28/12 _ 12/12 18/72 IT +4 =50 —200 =8 8160 8120 WC =9.7 8160 (3) — 0 27 Q• 24 1 / 2 40/12 •:. 7/6,20/2 PI =8 WC =6.7 0• 7/12 32/8,10/0 +4 =11 — 200 =10 0 +4 =39 r 200 =13 a 4' -I 18/6,10/2 8150 42/12 8150 4• 35/12 1 WC =3.5 • ' ' — 200 =11 8140 �:, J 16/6,30/4 a� a� c 0 0 813( W 812( 1, W$ 22/12 Lower floor level elevation - 8125' ?:.L 20/6,10/1 70/12 Note: Explanation of symbols is shown on Figure 6. M H " 105 291 LOG OF EXPLORATORY BORINGS Figure 3 HEPWORTH•PAWLAK GEOTECHNICAL 8140 38/12 LL- 17/6,6/6 0 >> 8130 w 12/12 +4 =30 28/12 _ —200 =7 +4 =50 —200 =8 _ 8120 70/12 Note: Explanation of symbols is shown on Figure 6. M H " 105 291 LOG OF EXPLORATORY BORINGS Figure 3 HEPWORTH•PAWLAK GEOTECHNICAL BORING 1 BORING 2 BORING 3 BORING 4 BORING 5 ELEV. =8162' ELEV. =8166' ELEV= 8168.5' ELEV.= 8171.5' ELEV. =8171' 8175 8175 (7)' (6)s 7/12 8165 (4) WC =20.6 8165 40/12 — 200 -43 O: LL =36 12/12 PI =12 18/12 33/12 ° 45/12 8155 1 WC =5.4 'o' WC =1.7 30/12 8155 +4 =40 — 200 =16 0 +4 =55 ,q: WC =7.6 • — =0 200 1 • 76/12 •Q: — 200 =14 —200 o • 0., 50/12 85/10 q' O� 8145 8145 a� a� 14/12 c - 200 =62 o 0 w L 8135 8125 8115 8105 2/12 65/12 36/12 +4 =10 - -200 -7 33/12 +4 =43 — 200 =10 22/12 WC =8.9 +4 =46 — 200 =10 50/12 Lower level floor elevation = 8125' 0 r 0 8135 w 8125 8115 8105 Note: Explanation of symbols is shown on Figure 6. 105 291 GgRedh LOG OF EXPLORATORY BORINGS Figure 2 HEPWORTH-PAWLAK GEOTECHNICAL BORING 11 BORING 12 BORING 13 BORING 14 BORING 15 ELEV. =8166' ELEV. =8158' ELEV. =8164' ELEV.= 8162.5' ELEV.= 8154.5' 8170 8170 8160 20/6,10/0 8160 J24/12 WC-6.9 27/12 +4 =36 (3) 50/12 200 =14 /6,10/0 18/6,50/6 12/12 27/12 8150 .4• 13/6,55/3 20/6,10/3 4� 18/12 51/12 WC =6.6 4' �• 41/6,10/0 - +4 =25 200 11/12 • 18/12 •• WC =5.5 - =15 •Q� WC =4.3 . +4 =22 67/12 8140 Q; +4 =31 - 200 =30 .0 8140 � -2oo =s 17/12 I Q� WC =12.5 0° —_ 4• — a +4-26= -200 =8 - 50/4 - a o •• Q� 38/12 0 • 0 8130 +4 =18 0. 8130 o Ld -2oo =8 w .4' Lower level floor elevation 8125• o° ° 20/12 .4' 70/9 q� +4 =10 +4 =55 -200 =8 8020 -200 =9 q' - 8020 - +4 =17 Q' o -200 =5 Q; o: 28/9,10/0 8110 q: 8110 E8100 8100 Note: Explanation of symbols is shown on Figure 6. H 105 291 �;� LOG OF EXPLORATORY BORINGS Figure 4 }i EPWORTH- PAWLAK GEOTECNNICAL 8165 8155 8145 a� f 8135 0 v a� 8125 — 8115 8105 BORING 16 BORING 17 BORING 18 ELEV.= 8162.5' ELEV.= 8163.5' ELEV. =8162' 3 (4) ) (4) 60/12 0 20/3 5/12 WC-24.4 — 200 =48 12/12 WC =28.7 — 200 =75 LL =25 PI =3 Lower Floor level elevation = 8125' 28/12 +4 =40 — 200 =11 22/12 12/12 +4 =27 —200 =5 Note: Explanation of symbols is shown on Figure 6. 8165 8155 8145 a� a> I 8135 c 0 0 a� 8125 8115 8105 105 291 �"'� LOG OF EXPLORATORY BORINGS Figure 5 HEPWORTH•PAWLAK GEOTECHNICA4. LEGEND: ® ASPHALT or CONCRETE( *); number in parentheses next to log indicates thickness in inches. ®FILL; silty to clayey sand and gravel with cobbles, possible small boulders at Boring 14, firm, moist, dark brown to brown. SAND (SM); slightly silty to silty, scattered gravel to gravelly, sandy silt layers at Boring 16, medium dense, moist to wet below the groundwater level, brown. SAND AND GRAVEL (SM —GM); stratified, silty, with scattered cobbles, medium dense to dense, moist to wet below the groundwater level, brown. GRAVEL (GM); sandy, with gravelly sand lenses, silty, with cobbles and boulders, medium dense to dense, moist to wet below the groundwater level, brown. Relatively undisturbed drive sample; 2 -inch I.D. California liner sample. Drive sample; standard penetration test (SPT), 1 3/8 inch I.D. split spoon sample, ASTM D -1586. 7/12 Drive sample blow count; indicates that 7 blows of a 140 pound hammer falling 30 inches were required to drive the California or SPT sampler 12 inches. Indicated 1h or 2 —inch diameter, slotted PVC pipe installed in the boring to the depth shown. Depth of free water measured in the boring on June 13, 2005. A water level summary is provided in Table 2. —1 Depth at which boring caved following drilling. TDepth of practical drilling refusal with solid flight and hollow stem augers. Borings 2, 9, 15 and 18 were advanced to the bottom boring depth using rotary /percussion casing advancer (ODEX). NOTES: 1. Boring 1 was drilled on April 26, 2005 with 3 -Y4—inch I.D. hollow stem auger. Borings 2 through 17 were drilled on April 25 to 29, and May 12, 2005 with 4 —inch diameter continuous flight power auger. Borings 2, 9 and 15 were advanced past auger refusal with 6 —inch diameter, rotary /percussion casing advancer (ODEX) on June 3, 6 and 8, 2005. Boring 18 was drilled using only ODEX on June 6, 2005. 2. Locations of exploratory borings were measured approximately by pacing from features shown on the 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. Water level readings shown on the logs were made at the time and under the conditions indicated. Fluctuations in water level may occur with time. 7. Laboratory Testing Results: WC = Water Content ( % ) LL = Liquid Limit ( % ) +4 = Percent retained on the No. 4 sieve PI = Plasticity Index ( % ) —200 = Percent passing No. 200 sieve 105 291 I '' I LEGEND AND NOTES I Figure 6 HEPWORTH-PAWLAK GEOTECHNICAL. HEPWORTH - PAWLAK GEOTECHNICAL, INC. TABLE 1 Job No. 105 291 SUMMARY OF LABORATORY TEST RESULTS Paae 1 of 3 SAMPLE LOCATION NATURAL MOISTURE CONTENT % NATURAL DRY DENSITY c GRADATION PERCENT PASSING NO. 200 SIEVE ATTERBERG LIMITS UNCONFINED COMPRESSIVE STRENGTH PSF SOIL TYPE BORING NO. DEPTH K GRAVEL ( %) SAND � %� LIQUID LIMIT % PLASTIC INDEX % 1 5 and 10, combined 5.4 40 44 16 Silty sand and gravel 20 62 Sandy silt 2 10 1.7 55 35 10 Slightly silty sandy gravel 40 10 83 7 Slightly silty sand with ravel 50 43 47 10 Slightly silty sand and ravel 3 15 7.6 31 55 14 Silty sand and gravel 30 8.9 46 44 10 Slightly silty sand and ravel 4 5 20.6 43 36 12 Clayey sand and gravel fill 6 15 and 20, combined 3.5 11 Slightly silty sandy gravel 7 5 9.7 27 28 8 Clayey gravelly sand fill 8 10 6.7 11 79 10 Slightly silty sand with ravel HEPWORTH - PAWLAK GEOTECHNICAL, INC. TABLE 1 Job No. 105 291 SUMMARY OF LABORATORY TEST RESULTS Paae 2 of 3 SAMPLE LOCATION NATURAL MOISTURE CONTENT % NATURAL DRY DENSITY c GRADATION PERCENT PASSING NO.200 SIEVE ATTERBERG LIMITS UNCONFINED COMPRESSIVE STRENGTH PSF SOIL TYPE BORING NO. DEPTH ft GRAVEL N SAND %1 LIQUID LIMIT % PLASTIC INDEX % 9 40 50 42 8 10 14' /z and 19' /z, combined 39 48 13 I1 5'/2 and 10y2, combined 6.9 36 50 14 12 15 4.3 31 60 9 20 12.5 26 66 8 13 20 5.5 22 48 30 40 10 81 9 14 15 and 20, combined 6.6 25 60 15 30 18 74 8 15 30 55 37 8 34 to 35 17 78 5 HEPWORTH - PAWLAK GEOTECHNICAL, INC. TABLE 1 Job No. 105 291 SUMMARY OF LABORATORY TEST RESULTS Paae3of3 SAMPLE LOCATION NATURAL MOISTURE CONTENT % NATURAL DRY DENSITY c GRADATION PERCENT PASSING NO. ATTERBERG LIMITS UNCONFINED COMPRESSIVE STRENGTH PSF SOIL TYPE BORING NO. DEPTH ft GRAVEL N SAND N LIQUID LIMIT % PLASTIC INDEX % 16 15 24.4 48 Very silty clayey sand 20 26.7 75 25 3 Sandy clayey silt 18 30 40 49 11 Slightly silty sand and ravel 50 27 68 5 Slightly silty gravelly sand HEPWORTH - PAWLAK GEOTECHNICAL, INC. TABLE 2 Job No. 105 291 SUMMARY OF GROUNDWATER LEVELS DEPTH TO GROUNDWATER (ft) Borine No. April 27 April 28 April 29 May 16 June 3 June 10 June 13 1 25 24'/2 25 22 21 2 P/z 21V2 2 Not drilled Not drilled Dry (auger) Backfilled Backfilled Buried redrilled 25'/2 (redrilled) 3 Not drilled In progress 30 29 28 28'/2 28'/2 4 Not drilled Not drilled Dry (auger) Backfilled Backfilled Backfilled Backfilled 5 Not drilled Not drilled Not drilled Not drilled Backfilled Backfilled Backfilled 6 26 24'/2 25 25 24 24 24 7 Dry (auger) Dry (auger) Dry (auger) Backfilled Backfilled Backfilled Backfilled 8 Not drilled Not drilled Dry (auger) Backfilled Backfilled Backfilled Backfilled 9 Not drilled Not drilled Dry (auger) Dry (auger) Dry (auger) 27 (redrilled) 27'/2 (redrilled) 10 Not drilled 32 31 30 29'/2 30 30 11 Not drilled Dry (auger) Dry (auger) Backfilled Backfilled Backfilled Backfilled 12 20 20 20 19 18'/2 19 19 13 29'/2 29%2 29'/2 29 28 28'/2 28%2 14 27'/2 27 27'/2 27 26 26'/2 26 15 Dry (auger) Dry (auger) Dry (auger) Dry (auger) Dry (auger) 18 (redrilled) 18 (redrilled) 16 16 25 24'/2 25 25 25 25 17 Not drilled Not drilled Dry (auger) Backfilled Backfilled Backfilled Backfilled 18 Not drilled Not drilled Not drilled Not drilled Not drilled 25'/2 (ODEX) 25%2 (ODEX) a July 19, 2005 Vail Development, LLC Attn: Douglas G. Hipskind 50 South Sixth Street Suite 1480 Minneapolis, Minnesota 55402 Job No. 105 291 Subject: Additional Recommendations, Proposed Four Seasons Resort, Vail Road and South Frontage Road West, Vail, Colorado Gentlemen: As requested by Horon Lee, S.E. with Niskian Menninger, we are providing additional recommendations for foundations and shoring at the subject site. The recommendations presented in this letter are in response to Mr. Lee's email dated June 27, 2005. We previously performed a geotechnical engineering study for the project and presented our findings in a report dated June 22, 2005, Job No. 105 291. Groundwater: It has been our experience in the area that the groundwater level could fluctuate and temporarily rise, mainly during seasonal runoff. A design groundwater elevation of 8140 feet appears reasonable for hydrostatic pressure and buoyancy calculations based on the current boring data. Long term monitoring of the groundwater level could be performed if a more accurate forecast is required. Mat Foundations: A soil subgrade modulus of 150 tcf (tons per cubic foot) should be used for design of the mat foundation. Soft wet sand and silt soils at design subgrade level should be removed and replaced with compacted structural fill, the same as that recommended for spread footings. Foundation Walls and Shoring: In our previous report, we recommended that foundation walls taller than 12 feet should be designed for a uniform lateral earth pressure in psf of 24 times the height of the wall in feet for the restrained condition. We understand that the excavation cuts will be supported with temporary shoring and the building will need to be designed for the full lateral earth pressure. The recommended lateral earth pressure diagram, shown on Figure 1, has been revised from our previous recommendations to account for the near surface condition. The pressure (Pa) was calculated using the following formula for tall, restrained walls: Pa = 0.65kaH, where ka = ytan2(45 -y /2). The formula assumes the on -site granular soils as backfill with the following properties: a moist unit weight (y) of 130 pcf, an internal friction angle (9) of 34 degrees and cohesion of zero. y Vail Development, LLC July 19, 2005 Page 2 We understand that a permanent shoring system cannot be used at the site due to property limit constraints. Typical temporary shoring systems used in the area consist of soldier pile and lagging with tiebacks, and soil nails. The soldier piles can be driven or drilled and set in place. We understand that soil nail walls will not be allowed to extend into town right -of -way. The shoring should be designed and installed by a contractor familiar with the subsurface conditions in the area. The groundwater level and boulders encountered in the subsoils will likely impact shoring construction. If you have any questions or need further assistance, please call our office. Sincerely, HEPWORTH — PAWLAK GEOTECHNICAL, INC. Trevor L. Knell, P.E. Reviewed by: Steven L. Pawlak, P.E. TLK/ksw attachment Figure I — Lateral Earth Pressure Diagram cc: Niskian Menninger — Attn: Horon Lee, S.E. Alpine Engineering, Inc. — Attn: Jim McNeil The John Hardy Group — Attn: David Brooks, Peter Speth Job No. 105 291 Gg&bech I PRESSURE IN PSF RESTRAINED WALL EARTH LOADING (NO HYDROSTATIC LOADING) H = HEIGHT OF WALL IN FEET (GREATER THAN 12 FEET) N TS I105 291 I GEPWOR H—P W AK I LATERAL EARTH PRESSURE DIAGRAM I Figure 1 I January 4, 2007 Tom Kassmel Town of Vail — Public Works Department 1309 Elkhorn Drive Vail, CO 81657 Re: FOUR SEASONS RESORT — VAIL, CO Layton Construction Job Number 06320 Subject: Partial Dewatering Permit Building Permit # B06 -0196 Dear Tom: Layton't CONSTRUCTING WITH INTEGRITY We are in receipt of your email dated January 3, 2007 and offer the following in response: 1. Dewatering work schedule - Enclosed. 2. Traffic control plan- No traffic control will be needed for mobilization of the drill rigs. _ 3. Updated dewaterina plan — Enclosed. Plans have been modified to show Discharge Line #2 connecting to Discharge Line #6 and flow to Spraddle Creels. Please do not hesitate to call me at (801) 563 -4360 with questions and/or concerns. Respectfully, La ton Construction Company Doug Carley Project Manager Enclosure DC /dc Cc: Dave Brooks Mark Reed °�� Layton Construction Company, Inc. 9090 South Sandy Parkway Sandy, LIT 84070 801.568.9090 Fax 801.569.5450 www.laytoncompanies.com , 1 Description ID moo 1010 Pre -Plan Work • Dur Date 10d 04JAN07 D25 17JAN07 11 11 V1 1: 15 22 29 1 05 12 19 26 02 1 1 1 Pre -Plan Work: EI- Mobilize Equipment to Site `-Bt- Surveying „. Electrical Distribution : Demobilization 1000 Mobilize Equipment to Site 2d 16JAN07 17JAN07 1020 Surveying 3d 18JAN07 22JAN07 1030 Electrical Distribution 20d 31JAN07 27FEB07 1040 Demobilization 2d 26MAR07 27MAR07 1050 Well Drilling 6d 23JAN07 30JAN07 1�04 Well Drilling %% Set Pumps Install Discharge Pipe Wells Established & Operational 1170 Set Pumps 3d 31 JAN07 02FEB07 1060 Install Discharge Pipe 3d 05FEB07 07FEB07 1070 Wells Established & Operational 2d 08FEB07 09FEB07 1180 Special Use Permit Executed 0 06FEB07 ........'. Special Use Permit Executed Lease Agreement Executed Full Dewatering Permit Issued Well Drilling -Set Pumps ....... ....... . Install Discharge Pipe 911 Wells Established & Operationaf 1190 Lease Agreement Executed 0 06FE807 1200 Full Dewatering Permit Issued 0 06FEB07 1080 Well Drilling 12d 23FEB07 12MAR07 1210 Set Pumps 4d 07MAR07 12MAR07 1090 Install Discharge Pipe 5d 13MAR07 19MAR07 1100 Wells Established & Operational 4d 20MAR07 23MAR07 1110 Well Drilling 5d 31JAN07 06FEB07 L.� jj Well Drilling Set Pumps %% Install Dishcarge Pipe Wells Established & Operational 1220 Set Pumps 2d 05FEB07 06FEB07 1120 Install Dishcarge Pipe 3d 07FEB07 09FEB07 1130 Wells Established & Operational 2d 12FEB07 13FEB07 1140 Well Drilling 12d 07FEB07 22FEB07 Well Drilling ^Set Pumps % Install Discharge Pipe « „. Wells Established & Operational 1230 Set Pumps 5d 15FEB07 21 FEB07 - 1150 Install Discharge Pipe 6d 22FEB07 01MAR07 1160 Wells Established & Operational 4d 02MAR07 07MAR07 Start date 04JAN07 Layton Construction Company FOUR SEASONS RESORT - VAIL DEWATERING PRELIMINARY SCHEDULE Early bar ® Progress bar Critical bar Summary bar Q Start milestone point Q Finish milestone point Finish date 27MAR07 Data date 04JAN07 Run date 04JAN07 Pa a number 1A 0 Primavera Systems, Inc. l� r November 17, 2006 Koechlein Consulting Engineers, Inc. Consulting Geotechnical Engineers 12364 W. Alameda Pkwy • Suite 115 • Lakewood, CO 80228 -2845 www.KCE- Denver.com Tom Kassmel Town of Vail Public Works 1309 Elkhorn Drive Vail, CO 81657 LAKEWOOD AVON /SILVERTHORNE (303) 989 -1223 (970) 949 -6009 (303) 989 -0204 FAX (970) 949 -9223 FAX Subject: Dewatering /Settlement Estimate Review Proposed Four Seasons Resort Vail Road and South Frontage Road West Vail, Colorado Job No. 06 -130 As requested we reviewed the information provided for the dewatering for the subject site and settlement estimates for adjacent buildings. The purpose of this letter is to provide our conclusions in regards to the proposed dewatering and settlement calculations. Hepworth- Pawlak Geotechnical (H -P) performed a subsurface investigation and presented the results in the report Geotechnical Engineering Study, Job No. 105 291, dated June 22, 2005. The subsurface conditions generally consisted of 3 to 11 feet of granular fill underlain by relatively dense, stratified silty sand and gravel containing occasional zones of cobbles and boulders. Silty sand lenses, varying from 2 to 11 feet thick, were occasionally encountered. The proposed dewatering system has been prepared by Griffin Dewatering, LLC (Griffin). The locations of the dewatering wells are shown on Coggins & Sons drawing XBS -2, Sheet 2 of 8, dated 8/28/06. Griffin has also shown well configuration and estimated ground water elevations on a Cross Section Well Schematic drawing. Griffin has indicated an approximate static ground water elevation of 8140, well screens would be installed from approximate elevation 8145 to elevation 8100, and ground water would be lowered to an elevation of 8107. The proposed shoring system has been designed by Coggins & Sons, Inc. We reviewed Griffins dewatering plans and calculations and H -P settlement calculations. H -P estimated ground settlement for adjacent buildings based on the ground water being lowered 40 feet and the dense granular soil conditions encountered in their borings. They also assumed an average compression potential of 0.1 % in their analysis. Their analysis estimates that a settlement potential of '/z inch could occur. H -P also stated that their analysis is only for soil compressibility and any material removed or "dredged" during dewatering has not been I- Tom Kassmel November 17, 2006 Job No. 06 -130 Page 2 of 2 KOECHLEIN CONSULTING ENGINEERS, INC. Consulting Geotechnica! Engineers considered. We are in agreement with their method of calculating settlement and in general agreement with their settlement calculations. Since different assumptions can be made for soil criteria that would influence dewatering and settlement calculations, we have the following concerns for this site: 1. Greater depths of dewatering may occur in localized areas for vaults, grease pits, elevator pits, and the permanent dewatering system, which could influence a building in the proximity of these structures. The location and elevation of these structures should be indicated on plans so that the influence on adjacent buildings could be evaluated. 2. Localized subsurface conditions such as the layers of silty sand could influence settlement. The location and depth of these layers should be logged as the wells are installed and as the soils are excavated. 3. Subsoil conditions beneath buildings could be different than the subsoil conditions encountered beneath the site. This would influence the soil criteria assumed beneath buildings. 4. The dewatering is based on estimated ground water flow conditions and not on pump tests. The ground water cone of depression beneath adjacent buildings could be different than what is being assumed. 5. Wells will be naturally developed and not gravel packed with filter medium so some loss of ground is a possibility. 6. A monitoring program of buildings for settlement and sediment measurements of pumped water is planned. What is the alternate plan by the development team if monitoring indicates loss of ground or settlement of adjacent buildings? 7. Is a permanent dewatering system planned for the building? Will the long term dewatering influence settlement beneath adjacent buildings? If so, what is the design layout, and elevation of the pipes, sumps, etc.? If we can be of further service, please contact us. KOECHLEIN CONSULTING ENGINEERS, INC. �J William P President Reviewed By: Scott B. Myers, P.E. Senior Engineer (4 copies sent) cc: Jehn Water Consultants I' LETTER OF TRANSMITTAL TO: Town of Vail - Public Works 1309 Elkhorn Drive Vail, CO 81657 Phone: 970 - 479 -2198 Fax: 970 - 479 -2166 We are sending you: ❑ Attached ❑ Under separate cover via ❑ Shop Drawings ❑ Prints ❑ Plans Layton CONSMUCTNVG WITH INTEGRITY DATE: 2/2/2007 JJOB NO.: 06320 ATTENTION: Tom Kassmel RE: Four Seasons Resort - Vail CO Building Permit #: B06 -0196 1/31/2007 1 Amended De;Tvatering Monitoring Plan (Final) ❑ Reviewed the following items: ❑ Specifications ❑ Copy of Letter ❑ Change Order ❑ Samples ❑ Other NO. DATE COPIES DESCRIPTION ❑ As Requested 1/31/2007 1 Amended De;Tvatering Monitoring Plan (Final) ❑ Reviewed ❑ Revise and Resubmit copies ❑ Please Complete and Return ❑ FOR YOUR REVIEW & SIGNATURE ❑ Prints Returned After Loan to Us ❑ FOR BIDS DUE ❑ PLEASE INITIAL EACH PAGE OF EACH CONTRACT ❑ For Approval ❑ No Exception Taken ❑ Resubmit copies for approval 121 For Your Use ❑ Make Corrections Noted ❑ Submit copies for distribution ❑ As Requested ❑ Returned for Corrections ❑ Return corrected prints ❑ For Review & Comment ❑ Rejected ❑ Reviewed ❑ Revise and Resubmit copies ❑ Please Complete and Return ❑ FOR YOUR REVIEW & SIGNATURE ❑ Prints Returned After Loan to Us ❑ FOR BIDS DUE ❑ PLEASE INITIAL EACH PAGE OF EACH CONTRACT ❑ PLEASE RETURN PLANS AND SPECIFICATIONS BY REMARKS: ITom - Attached is the final dewatering plan agreed to with Scorpio in connection with their easement. Please replace this document with the corresponding two pages submitted previously. Please call me if you have any questions. CC: File SIGNED: Doug Carley TJ Brink - HB Development Project Manager Dave Brooks - JHG Direct Ph: 801- 563 -4360 Bill Hardin - Zachry Construction Direct Fx: (801) 569 -5450 Layton Construction - MR, MC, MS Email: dcarley@layton- const.com Layton Construction Co., Inc. 9090 South Sandy Parkway Sandy, Utah 84070 801/ 568 -9090 Fax 801/ 569 -5450 AA/EEO Amended Plan to Monitor Dewatering Operations Four Seasons Resort — Vail, CO January 26, 2007 Layton Construction Dewatering will be monitored in the following ways at the site: Monitoring Activity #1 — Monitoring and settlement points will be established on each building on any adjacent properties, including the Scorpio Condominium Building and the 9 Vail Road Condominium Building. These points will be surveyed on a regular basis to determine if movement is taking place. These measurements will be done at regularly scheduled intervals, of every three days for the first three weeks of dewatering and then weekly if no significant movement has occurred. Significant movement shall be defined as any movement of more than one fourth of one inch. Monitoring Activity #2 - Monitoring of ground surface monuments on the outside of the shoring wall, as well as, monitoring points on the face of the shoring wall itself shall be established. Surveying of these points will take place on the same time schedule as surveying the settlement points on each building, see above. Monitoring Activity #3 — Four piezometers will be installed inside the proposed limits of excavation to measure the hydraulic head of groundwater. The actual location of the piezometers will be subject to approval by the developer and Town of Vail. These measurements will be done at regularly scheduled intervals, of once a day, unless results and/or conditions warrant more frequent testing. Monitoring Activity #4 — Upon completion of installation of the wells and the submersible pumps, the discharge from the wells will be checked by means of a Rossum Sand Tester. A port will be installed in all major discharge lines to allow the Rossum Sand Tester to be installed and moved from discharge line to discharge line. The port for the Rossum Sand Tester will be installed toward the end of each discharge header to monitor a group of wells based on one sample. According to the Environmental Health Office with the Town of Vail, Bill Carlson and as provided in the Groundwater discharge permit information, the required not to exceed measurements for discharge water into Spraddle Creek storm sewer system are as follows: - Over any 7 day period, the average particulate measurement must be less than 45 mg/liter. - Over any 30 day period, the average particulate measurement must be less than 30 mg/liter. If the results exceed the aforementioned values, the Rossum Sand Testers will be moved to individual wells for further testing. Attached is the proposed dewatering well locations, discharge locations, and port locations for the Rossum Sand Tester and flowmeters. Final locations will be coordinated with the Town of Vail. Also, Rossum Sand Tester procedures and a typical cross section on how this device connects to the discharge header are attached hereto for reference. Notwithstanding the foregoing, for the wells connected to Discharge Header #2 and for Well #'s 1 and 2 on Discharge Header #1, measurements shall be taken at the discharge line of each well twice per day during the first three weeks of dewatering operations, and then once per day thereafter if no significant turbidity is detected in the discharged water. Significant turbidity shall mean particulate measurement of any sample exceeding 30 mg/l. If significant turbidity is encountered, then the affected well shall be immediately adjusted to reduce its pumping rate to a level such that the turbidity of the discharge water falls below 30mg/l. All test results for the Rossum Sand Tester shall be noted in a log to be maintained by well(s), discharge lines and date and time of test. In the event that any Rossum Sand Tester measurement exceeds aforementioned values, then the well or wells so affected shall be temporarily shut down and a plan of action will be implemented in cooperation with the Town of Vail before such wells shall be reactivated. Monitoring Activity #5 - Monitoring of the nearby ground surface will also take place. Visual inspection to spot any ground movement will take place twice a day during the first three weeks of dewatering and then such inspection shall be once a day, unless conditions warrant more frequent visual inspection. If substantial settlement of the adjacent ground surface is observed using any of the above monitoring methods, the dewatering process will be fully and /or partially stopped and a plan of action will be implemented in cooperation with the Town of Vail to deal with the situation prior to the stopped dewatering activities being resumed. January 3, 2007 Tom Kassmel Town of Vail — Public.Works Department 1309 Elkhorn Drive Vail, CO 81657 Re: FOUR SEASONS RESORT — VAIL, CO Layton Construction Job Number 06320 Subject: Dewatering Discharge Line #2 Building Permit # B06 -0196 Dear Tom: Layton CONSTRUCTING W1M INTEGRITY Layton Construction is in receipt of a letter from Peak Land Consultants dated Sept. 27, 2006 in which they recommend not to use the 2'x2' inlet box and 12" CMP storm sewer at the southwest :comer of the Four Season site because it appeared to be undersized to. .handle a 25 year event and the added discharge flow coming from Discharge Line #2. I have confirmed with Alpine Engineering that the existing 2'x2' inlet actually captures.. -any; surface flow but if there is. a storm event and the dewatering system is pumping, it is . likely that the inlet will surcharge from the combined flows. To avoid this risk, Griffin Dewatering will manifold Discharge Line 2 to Discharge Line 6 and take the flow to Spraddle Creek at the SE corner, of the Four Seasons site. The dewatering drawings have been revised to incorporate this change. Respectfully, Layton Construction Company Doug arley Project Manager DC/dc Cc: T] Brink Dave Brooks Mark Reed Mike Colligan i l Layton Construction Company, Inc. 9090 South Sandy Parkway Sandy, UT 84070 801.568.9090 Fax 801.569.5450 www.laytoncompanies.com TOWN Department of Public Works & Transportation 1309 Elkhorn Drive Vail, CO 81657 970 - 479 -2158 Fax: 970 - 479 -2166 www.vailgov.com MEMO To: Doug Carley, Layton Construction From: Tom Kassmel, Town Engineer Re: Four Season, Dewatering Permit Date: 11/29/06 The Town of Vail has completed the review and peer review of the dewatering plan. The following are the remaining comments that must be addressed and the required conditions for dewatering. Comments: 1. A valid CDOT utility permit will be required. The permit must not refer to the lease agreement unless the lease agreement is signed and a copy submitted to the Town of Vail. 2. The discharge of line #2 needs to be verified. The Town would prefer it to be pumped to Spraddle Creek. 3. Provide an updated construction schedule for dewatering Conditions: 1. The subsurface soil conditions on the site shall be logged as the dewatering wells are installed, a copy of the logs shall be provided to the Town of Vail and the developer's Geotechnical/Dewatering consultant for review. 2. Prior to commencing dewatering, a pump test shall be completed to verify that the flowrate is within the estimated ground water flow. 3. An action plan shall be developed prior to commencing dewatering in the event excessive turbitity or settlement is encountered. What is Plan 'B'? 4. Logs of the monitoring activity shall be made available to the Town of Vail upon request. LETTER OF TRANSMITTAL TO: Colorado Inspection A enc P.O. Box 1618 ( Q E Eagle, CO 81631 D Phone: 970- 328 -17 n NOV 07 2006 Fax: 970 - 328 -179 TOWN OF VAIL We are sending you: El Attached ❑ Under separate cover via Layton 1h COASrRVC?WG W/7N INMG171711 -M& DATE: 11/7/2006 JJOB NO.: 6320 ATTENTION: Matt Royer RE: Four Seasons Resort - Vail CO Building Permit #: B06 -0196 ❑ Returned for Corrections ❑ Return corrected prints ❑ For Review & Comment ❑ Rejected ❑ Reviewed the following items: ❑ Shop Drawings ❑ Prints ❑ Plans ❑ Specifications ❑ Copy of Letter ❑ Change Order ❑ Samples ❑ Other 1 ❑ For Approval ❑ No Exception Taken ❑ Resubmit copies for approval 21 For Your Use ❑ Make Corrections Noted ❑ Submit copies for distribution ❑ As Requested ❑ Returned for Corrections ❑ Return corrected prints ❑ For Review & Comment ❑ Rejected ❑ Reviewed ❑ Revise and Resubmit copies ❑ Please Complete and Return ❑ FOR YOUR REVIEW & SIGNATURE ❑ Prints Returned After Loan to Us ❑ FOR BIDS DUE ❑ PLEASE INITIAL EACH PAGE OF EACH CONTRACT ❑ PLEASE RETURN PLANS AND SPECIFICATIONS BY REMARKS: Matt - Attached is a copy of the revised and extended Ground Water Discharge Permit from State of Colorado. Please insert behind the Ground Water Permit tab in the G & E Permit Booklet. Please call if you have any questions. V CC: File SIGNED: Doug Carley Dave Brooks - JHG Project Manager Tom Kassmel - TOV Direct Ph: 801- 563 -4360 Warren Campbell - TOV Direct Fx: (801) 569 -5450 Leonard Sandoval - TOV Email: dcarley (a)lavton- const.com Layton Construction Co., Inc. 9090 South Sandy Parkway Sandy, Utah 84070 801/ 568 -9090 Fax 801/ 569 -5450 AA/EEO STATE OF COLORADO Bill Owens, Governor Dennis E. Ellis, Executive Director Dedicated to protecting and improving the health and environment of the people of Colorado 4300 Cherry Creek Dr. S. Denver, Colorado 80246 -1530 Phone(303)692 -2000 TDD Line (303) 691 -7700 Located in Glendale, Colorado http://www.cdphe.state.co.us October 31, 2006 Laboratory Services Division 8100 Lowry Blvd. Denver, Colorado 80230 -6928 (303) 692 -3090 Douglas Hipskind, Vice Manager _Vail Development, LLC 50 S. 6th Street, Ste 1480 Minneapolis, MN 55402 RE: Amended Certification, for the Colorado Wastewater Discharge Permit System Permit Number: COG-700000, Facility Number: COG - 072206 Dear Mr. Hipskind: pF • COQ O * 1876 f Colorado Department of Public Health and Environment Enclosed please find a copy of the amended Certification, which was issued under the Colorado Water Quality Control Act. You are legally obligated to comply with all terms and conditions of the permit and certifications. Please read the amendment and if you have any questions, contact me at (303) 692 -3531. Should you have questions on the amendment fee, please call (303) 692 -3529. Sincerely, WE I • Loretta Houk Water Quality Protection Section WATER QUALITY CONTROL DIVISION Enclosure xc: Regional Council of Government Eagle County, Local County Health Department Mark Kadnuck/Andy Poirot, D.E., Technical Services Unit, WQCD Permit File Permit Fees /lh amd -cert Permit No. COG- 070000 Facility No. COG - 072206 Page I AMENDMENT TO CERTIFICATION AUTHORIZATION TO DISCHARGE UNDER THE CDPS INDUSTRIAL GENERAL PERMIT FOR CONSTRUCTION DEWATERING OPERATIONS (SIC No: 1629) Category 27, Subcategory 5, General Permits, Current fee $358.00 for 1 year per CRS 25 -8 -502 Amendment fee is 25% of $358 = $89.50 This permit specifically authorizes, Vail Development, LLC c% Four Seasons Resort Douglas Hipskind 50 South 6't' Street Minneapolis, MN 55402 (612) 313 -0123 with the facility contact of James McNeil, P.E., Principal, Alpine Engineers, Incorporated (970) 453 -6064 to discharge from the Four Seasons Resort Project, located in the NE %4 of Section 7, TSS, R80 W (Longitude 106'23'30" Latitude 39 °38'45 ' ), in Vail, Eagle County, Colorado (81657); from the discharge points identif ed as Outfalls 00IA -002A, as shown in figures 1 -3 of the permit and further identified and described in this table. Estunated FiD1it Rate OOIA -002A Discharges of treated groundwater prior to entering Gore Creek. Max = 5500 gpm ea. The discharges are to Gore Creek, Segment 8 of the Eagle River Sub- basin, Upper Colorado River Basin, found in the Classifications and Numeric Standards for the Upper Colorado River Basin (5 CCR 1002 -33); last update effective March 2, 2006 Segment 8 is classified for the following uses: Recreation, Class ]a; Aquatic Life, Class 1 (Cold); Agriculture; Water Supply. Salinity (TDS) monitoring of the discharge will be required. Phosphorus monitoring of the discharge will not be required. Antidegradation review does not apply to this permit because no parameters limited by water quality standards other than pH are expected. Refer to page 4 of the permit for applicable limitations and to page 5 for monitoring requirements. The permittee shall implement and maintain the Best Management Practices (BMP) for the prevention of erosion and the control ofsolid and liquid pollutants due to the discharge. BMPs include various options, such as: modification of the pipe discharge structure to dispersefows; containment of water by hay bales or other comparable structures; the use ofgeocloth, filter fabric, or plastic sheeting for protection of containment structures; rip -rap; and/or any other approved methods. /f groundwater contamination is encountered, then the permittee is to contact the Division and, if appropriate, the owner of the collection system receiving the discharge. Since the discharge of contaminated groundwater is not covered under this permit, the permittee shall immediately apply for a groundwater remediation certification, which will include appropriate requirements foradditional discharge monitoring and on -site environmental response capabilities. The permittee shall provide the Division with any additional monitoring data on the permitted discharge collected for entities other than the Division. This will be supplied to the Division within 48 hours of the receipt of the data by the permittee. This amendment changes the flow to 5500 gpm All correspondence relative to this facility should reference the specifc facility number, COG - 072206. Raymond Nalepa October 27, 2006 AMENDED AND EFFECTIVE• OCTOBER 30 2006 EXPIRATION: MAY 17, 2007 This facility permit contains 19 pages. Revised 1013112006 Revised /0/3//2006 LETTER OF TRANSMITTAL TO: Town of Vail - Public Works 1309 Elkhorn Drive Vail, CO 81657 Phone: 970 - 479 -2198 Fax: 970 - 479 -2166 We are sending you: ❑ Attached ❑ Under separate cover via ❑ Shop Drawings ❑ Prints ❑ Plans ❑ Copy of Letter ❑ Change Order ❑ Samples Layton 00NSTR110"NO W1THMTECRI1Y DATE: 2/2/2007 JJOB NO.: 06320 ATTENTION: Tom Kassmel RE: Four Seasons Resort - Vail CO Building Permit #: B06 -0196 1/31/2007 1 Amended Dewatering Monitoring Plan (Final) ❑ Reviewed the following items: ❑ Specifications ❑ Other NO. DATE COPIES I DESCRIPTION ❑ As Requested 1/31/2007 1 Amended Dewatering Monitoring Plan (Final) ❑ Reviewed ❑ Revise and Resubmit copies ❑ Please Complete and Return ❑ FOR YOUR REVIEW & SIGNATURE ❑ Prints Returned After Loan to Us ❑ FOR BIDS DUE ❑ PLEASE INITIAL EACH PAGE OF EACH CONTRACT ❑ For Approval ❑ No Exception Taken ❑ Resubmit copies for approval 21 For Your Use ❑ Make Corrections Noted ❑ Submit copies for distribution ❑ As Requested ❑ Returned for Corrections ❑ Return corrected prints ❑ For Review & Comment ❑ Rejected ❑ Reviewed ❑ Revise and Resubmit copies ❑ Please Complete and Return ❑ FOR YOUR REVIEW & SIGNATURE ❑ Prints Returned After Loan to Us ❑ FOR BIDS DUE ❑ PLEASE INITIAL EACH PAGE OF EACH CONTRACT ❑ PLEASE RETURN PLANS AND SPECIFICATIONS BY REMARKS: Tom - Attached is the final dewatering plan agreed to with Scorpio in connection with their easement. Please replace this document with the corresponding two pages submitted previously. Please call me if you have any questions. CC: File SIGNED: Doug Carley TJ Brink - HB Development Project Manager Dave Brooks - JHG Direct Ph: 801- 563 -4360 Bill Hardin - Zachry Construction Direct Fx: (801) 569 -5450 Layton Construction - MR, MC, MS Email: dcarlev@lavton- const.com Layton Construction Co., Inc. 9090 South Sandy Parkway Sandy, Utah 84070 801/ 568 -9090 Fax 801/ 569 -5450 AA/EEO Amended Plan to Monitor Dewatering Operations Four Seasons Resort — Vail, CO January 26, 2007 Layton Construction Dewatering will be monitored in the following ways at the site: Monitoring Activity #1 — Monitoring and settlement points will be established on each building on any adjacent properties, including the Scorpio Condominium Building and the 9 Vail Road Condominium Building. These points will be surveyed on a regular basis to determine if movement is taking place. These measurements will be done at regularly scheduled intervals, of every three days for the first three weeks of dewatering and then weekly if no significant movement has occurred. Significant movement shall be defined as any movement of more than one fourth of one inch. Monitoring Activity #2 - Monitoring of ground surface monuments on the outside of the shoring wall, as well as, monitoring points on the face of the shoring wall itself shall be established. Surveying of these points will take place on the same time schedule as surveying the settlement points on each building, see above. Monitoring Activity #3 — Four piezometers will be installed inside the proposed limits of excavation to measure the hydraulic head of groundwater. The actual location of the piezometers will be subject to approval by the developer and Town of Vail. These measurements will be done at regularly scheduled intervals, of once a day, unless results and/or conditions warrant more frequent testing. Monitoring Activity #4 — Upon completion of installation of the wells and the submersible pumps, the discharge from the wells will be checked by means of a Rossum Sand Tester. A port will be installed in all major discharge lines to allow the Rossum Sand Tester to be installed and moved from discharge line to discharge line. The port for the Rossum Sand Tester will be installed toward the end of each discharge header to monitor a group of wells based on one sample. According to the Environmental Health Office with the Town of Vail, Bill Carlson and as provided in the Groundwater discharge permit information, the required not to exceed measurements for discharge water into Spraddle Creek storm sewer system are as follows: - Over any 7 day period, the average particulate measurement must be less than 45 mg/liter. - Over any 30 day period, the average particulate measurement must be less than 30 mg/liter. If the results exceed the aforementioned values, the Rossum Sand Testers will be moved to individual wells for further testing. Attached is the proposed dewatering well locations, discharge locations, and port locations for the Rossum Sand Tester and flowmeters. Final locations will be coordinated with the Town of Vail. Also, Rossum Sand Tester procedures and a typical cross section on how this device connects to the discharge header are attached hereto for reference. Notwithstanding the foregoing, for the wells connected to Discharge Header #2 and for Well #'s 1 and 2 on Discharge Header #1, measurements shall be taken at the discharge line of each well twice per day during the first three weeks of dewatering operations, and then once per day thereafter if no significant turbidity is detected in the discharged water. Significant turbidity shall mean particulate measurement of any sample exceeding 30 mg/1. If significant turbidity is encountered, then the affected well shall be immediately adjusted to reduce its pumping rate to a level such that the turbidity of the discharge water falls below 30mg/l. All test results for the Rossum Sand Tester shall be noted in a log to be maintained by well(s), discharge lines and date and time of test. In the event that any Rossum Sand Tester measurement exceeds aforementioned values, then the well or wells so affected shall be temporarily shut down and a plan of action will be implemented in cooperation with the Town of Vail before such wells shall be reactivated. Monitoring Activity #5 - Monitoring of the nearby ground surface will also take place. Visual inspection to spot any ground movement will take place twice a day during the first three weeks of dewatering and then such inspection shall be once a day, unless conditions warrant more frequent visual inspection. If substantial settlement of the adjacent ground surface is observed using any of the above monitoring methods, the dewatering process will be fully and/or partially stopped and a plan of action will be implemented in cooperation with the Town of Vail to deal with the situation prior to the stopped dewatering activities being resumed. January 3, 2007 Tom Kassmel Town of Vail — Public.Works Department 1309 Elkhorn Drive Vail, CO 81657 Re: FOUR SEASONS RESORT — VAIL, CO Layton Construction Job Number 06320 Subject: Dewatering Discharge Line #2 Building Permit # B06 -0196 Dear Tom: Layton CCNSTRUCTMG WITH INTEGRITY Layton Construction is in receipt of a letter from Peak Land Consultants dated Sept. 27, 2006 in which they recommend not to use the 2'x2' inlet box and 12" CMP storm.sewer at the southwest :corner of the Four Season site because it appeared to be undersized to. handle a 25 year event and the added discharge flow coming from Discharge Line #2. I have confirmed with Alpine Engineering that the existing 2'x2' inlet actually captures.. any. surface flow but if there is a storm event and the dewatering system is pumping, it is likely that the inlet will surcharge from the combined flows:' To avoid this risk, Griffin Dewatering will manifold Discharge Line 2 to Discharge Line 6 and take the flow to Spraddle Creek at the SE corner, of the Four Seasons site. The dewatering drawings have been revised to incorporate this change. Respectfully, Layton Construction Company Doug arley Project Manager DC/dc Cc: TJ Brink Dave Brooks Mark Reed Mike Colligan 4) Layton Construction Company, Inc. 9090 South Sandy Parkway Sandy, UT 84070 801.568.9090 Fax 801.569.5450 www.laytoncompanies.com tll �l�l Department of Public Works & Transportation 1309 Elkhorn Drive Vail, CO 81657 970 - 479 -2158 Fax: 970 - 479 -2166 www.vailgov.com MEMO To: Doug Carley, Layton Construction From: Tom Kassmel, Town Engineer Re: Four Season, Dewatering Permit Date: 11/29/06 The Town of Vail has completed the review and peer review of the dewatering plan. The following are the remaining comments that must be addressed and the required conditions for dewatering. Comments: 1. A valid CDOT utility permit will be required. The permit must not refer to the lease agreement unless the lease agreement is signed and a copy submitted to the Town of Vail. 2. The discharge of line #2 needs to be verified. The Town would prefer it to be pumped to Spraddle Creek. 3. Provide an updated construction schedule for dewatering Conditions: 1. The subsurface soil conditions on the site shall be logged as the dewatering wells are installed, a copy of the logs shall be provided to the Town of Vail and the developer's Geotechnical/Dewatering consultant for review. 2. Prior to commencing dewatering, a pump test shall be completed to verify that the flowrate is within the estimated ground water flow. 3. An action plan shall be developed prior to commencing dewatering in the event excessive turbitity or settlement is encountered. What is Plan'B'? 4. Logs of the monitoring activity shall be made available to the Town of Vail upon request. STATE OF COLORADO Bill Owens, Governor Dennis E. Ellis, Executive Director Dedicated to protecting and improving the health and environment of the people of Colorado 4300 Cherry Creek Dr. S. Denver, Colorado 80246 -1530 Phone (303) 692 -2000 TDD Line (303) 691 -7700 Located in Glendale, Colorado http://www.cdphe.state-co-us October 31, 2006 Laboratory Services Division 8100 Lowry Blvd. Denver, Colorado 80230 -6928 (303) 692 -3090 Douglas Hipskind, Vice Manager _Vail Development, LLC 50 S. 6th Street, Ste 1480 Minneapolis, MN 55402 RE: Amended Certification, for the Colorado Wastewater Discharge Permit System Permit Number: COG-700000, Facility Number: COG - 072206 Dear Mr. Hipskind: of cot_o He / O • J876 Colorado Department of Public Health and Environment Enclosed please find a copy of the amended Certification, which was issued under the Colorado Water Quality Control Act. You are legally obligated to comply with all terms and conditions of the permit and certifications. Please read the amendment and if you have any questions, contact me at (303) 692 -3531. Should you have questions on the amendment fee, please call (303) 692 -3529. Sincerely, Loretta Houk Water Quality Protection Section WATER QUALITY CONTROL DIVISION Enclosure xc: Regional Council of Government Eagle County, Local County Health Department Mark Kadnuck/Andy Poirot, D.E., Technical Services Unit, WQCD Permit File Permit Fees /lh amd -cert