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HAGGERTY MULTI-FAMILY
Project # 250389.01/.02
Bozeman, Montana
FEBRUARY 2026
DRAINAGE REPORT FOR HAGGERTY MULTI-FAMILY CERTIFICATION I hereby state that this drainage report has been prepared by me or under my supervision and meets the standard of care and expertise which is usual and customary in this community of professional engineers. The analysis has been prepared utilizing procedures and practices specified by the City of Bozeman and within the standard accepted practices. Robert Egeberg, P.E. Date 2/27/2026
February 2026 Project No. 250389.01/.02 DRAINAGE REPORT HAGGERTY MULTI-FAMILY BOZEMAN, MONTANA 59715 SITE NARRATIVE The purpose of this drainage report is to present a summary of calculations to quantify the stormwater runoff for the Haggerty Multi-Family project (referred to in this document as “the project”). The proposed project includes two new residential buildings with 5 units in each building for a total of 10 units. All design criteria and calculations are in accordance with the City of Bozeman Design and Construction Standards, dated October 2024. The site stormwater improvements have been designed with the intent of meeting the current drainage regulations for the City of Bozeman. LOCATION The development site is one lot located on the south side of Haggerty Lane in Bozeman, Montana. The legal description of the property is: MINOR SUB 16B, S08, T02 S, R06 E, LOT 2A1, ACRES 0.468, REARR ELKS CLUB PROPERTY. EXISTING SITE CONDITIONS The project location is currently an undeveloped lot with native grass and vegetation. The existing area generally slopes southeast to northwest at 4.6% towards Haggerty Lane. The nearest storm drain inlet is located adjacent to the site on Haggerty Lane. The total area of the site is 20,373 square feet (0.468 acres). The project site is bordered by the Bozeman Softball Complex to the south and commercial properties to the east and west. PROPOSED CONDITIONS The proposed project includes the construction of two new multi-story buildings with an asphalt drive aisle, concrete sidewalks, pervious pavers, and landscaped areas. The new improvements area will be treated as two basins. Runoff from most of the building roof areas will be collected via downspouts and conveyed to an underground gravel storage system located in the center of the proposed drive aisle. Outflow from the site
Drainage Report Page 2 of 6 FEBRUARY 2026 will be limited to the pre-development flowrate. Runoff exits the storage system through an 8” perforated pipe and into an outlet control structure. A new 12” storm drain connects the outlet structure to the existing inlet on Haggerty Lane. HYDROLOGY The modified rational method was used to determine peak runoff rates and volumes since all basins within the project are under 5 acres. The rational formula provided in the City of Bozeman Design and Construction Standards was used to calculate the peak runoff rates on-site, time of concentration, rainfall intensities, etc. For asphalt, roof areas, and concrete surfaces, a runoff coefficient of 0.95 was assumed, for landscape surfaces, a runoff coefficient of 0.15 was assumed, and for gravel surfaces, a runoff coefficient of 0.70 was assumed. The project proposes the construction of an underground gravel detention system to manage the on-site runoff. All hydrology calculations have been provided in Appendix B of this report. A. Pre-Development Basins For the following sections, please refer to Appendix A – Exhibit A of this report which shows and labels the existing drainage basins for the project. Existing basins were evaluated to include areas that contribute runoff to the site. This includes a portion of the neighboring property to the east of the site and the Bozeman Softball Complex to the south of the site. Existing Basin A On-site and Off-site Existing Basin A has 26,387 square feet of unimproved area and 374 square feet of gravel area. Runoff generated in this basin flows from southeast to northwest towards Haggerty Lane. Existing Basin A has a peak flow of 0.30 cfs for the 10-year storm event. Existing Basin B Off-site Existing Basin B has 1,419 square feet of unimproved area, 799 square feet of gravel area, and 50,692 square feet of lawn area. Runoff generated in this basin flows from the softball field complex southeast to northwest towards the project site and ultimately to Haggerty Lane. Existing Basin B has a peak flow of 0.24 cfs and a water quantity storage requirement of 1,201 cubic feet for the 10-year storm event. Existing Basin C Off-site Existing Basin C has 1,691 square feet of unimproved area, 689 square feet of gravel, and 1,230 square feet of lawn area. Runoff generated in this basin flows from southeast
Drainage Report Page 3 of 6 FEBRUARY 2026 to northwest to the property directly east of the project site and ultimately into Haggerty Lane. Existing Basin C has a peak flow of 0.06 cfs for the 10-year storm event. B. Post-Development Basins For the following sections, please refer to Appendix A – Exhibit B of this report, which shows and labels the post-development basins. A geotechnical report was completed in January 2026 by Allied Engineering and is included in Appendix D. Infiltration rates have not been included in the required detention storage volume calculations to be conservative. Peak flows were calculated for the 10-year storm event for each basin and the 100-year storm event was also evaluated, see Appendix B. Basin 1 Basin 1 has 1,184 square feet of concrete, 1,811 square feet of permeable pavers, 2,843 square feet of asphalt, 7,797 square feet of roof area, and 1,651 square feet of landscape area. This basin also includes 799 square feet of gravel area, 50,692 square feet of lawn area, and 1,149 square feet of unimproved area from the existing Basin B (off-site) that will contribute runoff to the site. Runoff within Basin 1 flows into the proposed drive aisle and enters the gravel storage pit via the surface through the permeable pavers. Within the gravel pit, a perforated underdrain pipe brings water to an overflow structure where it is then released to the existing inlet on Haggerty Lane at the allowable pre-development flowrate. Proposed Basin 2 has water exiting the property without storage, so Basin 1 is sized to limit the flow from Basins 1 and 2 to pre-development flowrates. Therefore, the combined flowrate from Basin 1 and 2 matches the combined pre-development flowrate. Basin 1 has a peak flow of 1.80 cfs and a water quantity storage requirement of 781 cf for the 10-year storm. Basin 2 Basin 2 has 3,196 square feet of concrete, 240 square feet of permeable pavers, 1,549 square feet of gravel area, 1,428 square feet of roof area, and 4,617 square feet of landscape area. This basin also includes 689 square feet of gravel area, 1,230 square feet of lawn area, and 1,691 square feet of unimproved area from the existing Basin C (off-site) that will contribute runoff to the site. Runoff within Basin 2 sheet flows towards the east and west property boundaries of the site and then flows along the boundaries. Runoff from Basin 2 ultimately enters Haggerty Lane as it has historically. Basin 2 has a peak flow of 0.44 cfs. REQUIRED STORAGE VOLUME CALCULATIONS Underground Gravel Storage System
Drainage Report Page 4 of 6 FEBRUARY 2026 The 10-year peak flow from Basin 1 is detained by the proposed underground storage system. Basin 1 has a total area of 68,196 square feet (1.57 acres) and has a runoff coefficient of 0.47, and a required water quantity storage of 781 cubic feet. Using a void space of 30%, the gravel pit has a total storage volume of 1,020 cubic feet, making the system adequate to meet the storage requirements. Required Volume = 781 cubic ft Gravel Pit Dimensions = 170 ft X 4 ft X 5 ft X 0.30 = 1,020 cubic feet HYDRAULICS All storm drainage pipes were sized to handle peak flow resulting from the minor storm event with a minimum slope to maintain a full-flow velocity of at least 2.5 feet per second while limiting the full flow velocity to a maximum of 12 feet per second. See Appendix C for hydraulics calculations. Water Quality The City of Bozeman has a requirement to capture or reuse the runoff generated from the first 0.5 inches of rainfall from a 24-hour storm. We meet this requirement by detaining the water quality volume in the underground gravel system. Stormwater systems need to be maintained, per the recommendations in the Operations and Maintenance Manual, see Appendix C. A. Calculations WQV = ((P x Rv x A) / 12) x 43,560 Where: WQV=Water Quality volume P=Water Quality Rainfall Depth, inches (0.5-inches) Rv=The Unitless Runoff Coefficient, Rv=0.5+0.9(I) I=the percent impervious cover draining to the facility A=total site area draining to the structure Basin 1 Water Quality Volume = 0.5in x 0.22 x 1.57 ac x (1ft/12in) x 43,560ft/ac = 615 cf Stormwater Storage Drawdown Time The required water quantity storage for the proposed gravel pit is 781 cubic feet and the allowable discharge rate is 0.21 cfs.
Drainage Report Page 5 of 6 FEBRUARY 2026 Drawdown time = (781 cf/0.21 cfs) x (1 hr/3600 sec) = 1.04 hours Therefore, the proposed gravel pit drains in 1.04 hours and is well within the 72-hour maximum drain-down time. OUTLET STRUCTURE The orifice outlet structure at the north side of the drive aisle will control flow from the gravel pit to the existing inlet on Haggerty Lane. The proposed orifice was defined with the following equation: Q= C x A x (2 x g x h)0.5 Q = flow cfs C = discharge coefficient A = open area (square feet) g = gravity constant h = head water depth (ft) 0.21 cfs = 0.6 x 0.0308 x (2 x 32.2 x 2) 0.5 CONCLUSION Runoff generated from Basin 1 will be captured and detained on-site in the underground gravel storage system proposed for the development of the project site. The detention system has been designed to store the minor storm event while releasing a portion of the storm event at the pre-development peak flow rate. There is one planned outlet structure. During the large storm event, the underground storage system will overflow into the larger weir within the overflow structure and discharge into the proposed outflow pipe. Runoff from the outflow pipe flows to the existing inlet in Haggerty Lane and discharges to the north side of Haggerty Lane as it has historically. In the case of the large storm event, no runoff will impact the existing or proposed structures of the Haggerty Multi-Family project.
Drainage Report Page 6 of 6 FEBRUARY 2026 APPENDICES Appendix A – Stormwater Basins Appendix B – Hydrology Calculations Appendix C - Hydraulic Calculations Appendix D – O&M Plan Appendix E – Geotechnical Report
HAGGERTY MULTI-FAMILY
Project # 250389.01/.02 APPENDIX A STORMWATER BASINS
HAGGERTY MULTI-FAMILY
Project # 250389.01/.02 APPENDIX B HYDROLOGY CALCULATIONS
Input parameters in light blue 10year design storm26,387 0.61 0.20 1.00 0.20 0.20 0.121152374 0.01 0.801.000.800.800.00687126,761 0.61 0.13*Input values for Runoff Coefficients (C) from 'Runoff Coefficients' tabTotal QuantityRainfallRainfallRunoff Volume Discharge VolumePeak FlowDuration, tIntensity, i= Cwd x SAj x i x t= d x t=C*I*A(min)(in/hr)(ft3) (ft3) (ft3/sec)0 0.00 0.00 0.00 0.0053.87148.640.000.50102.83217.380.000.36152.29263.860.000.29201.84282.680.000.24251.56299.580.000.20301.38318.010.000.18351.22328.000.000.16401.09334.910.000.14451.00345.660.000.13500.91349.500.000.12550.84354.880.000.11600.79364.100.000.101200.41377.930.000.051800.29400.970.000.043600.17470.100.000.027200.10553.060.000.0114400.07785.350.000.01Water Quantity Storage: 785 ft3Peak Flow: 0.30 ft3/sToC 14.5 minWater Quality Storage:Where: P = 0.5inchesRv = 0.0626I = 0.01A = 0.61acres0Water Quality Storage: 70 ft3 Water Quality Storage70 ft3Total Required Storage 785 ft3P(10-yr, 24 hr) 1.7FLOW∆ ELEV FLOWVELOCITYTIME OF FLOW TYPELENGTH (FT)(FT)SLOPE (%)n(FT/S)CONC. (MIN)SHEET FLOW351.23.4%0.150--4.7SHALLOW CONC.2049.44.6%--0.359.8414.5 Linear Interpolationx14.5y0.30x010y00.362x115y10.293A = total site area draining to the structure, in acresThese are the volumes that must be mitigated470.10553.06785.35WQV = Water Quality Volume, in acre-feetP = Water Quality Rainfall Depth, inches (0.5-inches) Rv = the unitless runoff coefficient, Rv = 0.05 + 0.9(I) 349.50354.88364.10377.93400.97I = the percent impervious cover draining to the facility, in decimal282.68299.58318.01328.00334.91345.66= Runoff Volume - Discharge Volume(ft3)0.00148.64217.38263.86Total Quantity Total QuantityTotal QuantityTotal QuantitySite DetentionPercolation Discharge Rate:TotalsFrequency Factor (Cf)C x CfCalculation Value (C') =(C x Cf) < or = 1C' x A (Acres)Unimproved AreaGravelPre-DevelopedTime of ConcentrationBasin A (10 YR)RUNOFF CALCULATIONSTotal Required Storage:Surface TypeArea (ft2)Area (Acres)Runoff Coefficient (C)*
Input parameters in light blue 100year design storm26,387 0.61 0.20 1.25 0.25 0.25 0.151441374 0.01 0.801.251.001.000.00858926,761 0.61 0.16*Input values for Runoff Coefficients (C) from 'Runoff Coefficients' tabTotal QuantityRainfallRainfallRunoff Volume Discharge VolumePeak FlowDuration, tIntensity, i= Cwd x SAj x i x t= d x t=C*I*A(min)(in/hr)(ft3) (ft3) (ft3/sec)0 0.00 0.00 0.00 0.0056.09292.370.000.97104.45427.280.000.71153.61519.940.000.58202.89554.980.000.46252.46590.510.000.39302.18627.960.000.35351.92645.240.000.31401.72660.600.000.28451.57678.370.000.25501.44691.330.000.23551.33702.370.000.21601.24714.370.000.201200.61702.850.000.101800.41708.610.000.073600.22760.460.000.047200.14967.860.000.0214400.101355.000.000.02Water Quantity Storage: 1,355 ft3Peak Flow: 0.61 ft3/sToC 13.8 minWater Quality Storage:Where: P = 0.5inchesRv = 0.0626I = 0.01A = 0.61acres0Water Quality Storage: 70 ft3 Water Quality Storage70 ft3Total Required Storage 1,355 ft3P(100-yr, 24 hr) 2.34FLOW∆ ELEV FLOWVELOCITYTIME OF FLOW TYPELENGTH (FT)(FT)SLOPE (%)n(FT/S)CONC. (MIN)SHEET FLOW351.23.4%0.150--4.0SHALLOW CONC.2049.44.6%--0.359.8413.8x13.8y0.61x010y00.712x115y10.578 Linear InterpolationI = the percent impervious cover draining to the facility, in decimalA = total site area draining to the structure, in acresThese are the volumes that must be mitigatedTime of ConcentrationPre-Developed760.46967.861355.00WQV = Water Quality Volume, in acre-feetP = Water Quality Rainfall Depth, inches (0.5-inches) Rv = the unitless runoff coefficient, Rv = 0.05 + 0.9(I) 678.37691.33702.37714.37702.85708.61519.94554.98590.51627.96645.24660.60Site Detention= Runoff Volume - Discharge Volume(ft3)0.00292.37427.28Total Quantity Total QuantityTotal QuantityTotal QuantityC' x A (Acres)Unimproved AreaGravelTotalsBasin A (100-YR) RUNOFF CALCULATIONSTotal Required Storage:Surface TypeArea (ft2)Area (Acres)Runoff Coefficient (C)*Frequency Factor (Cf)C x CfCalculation Value (C') =(C x Cf) < or = 1
Input parameters in light blue 10year design storm1,419 0.03 0.20 1.00 0.20 0.20 0.006515799 0.02 0.801.000.800.800.01467450,692 1.16 0.151.000.150.150.17455952,910 1.21 0.20Total QuantityRainfallRainfallRunoff Volume Discharge VolumePeak FlowDuration, tIntensity, i= Cwd x SAj x i x t= d x t=C*I*A(min)(in/hr)(ft3) (ft3) (ft3/sec)0 0.00 0.00 0.00 0.0053.87227.260.000.76102.83332.380.000.55152.29403.440.000.45201.84432.210.000.36251.56458.050.000.31301.38486.240.000.27351.22501.510.000.24401.09512.080.000.21451.00528.520.000.20500.91534.390.000.18550.84542.610.000.16600.79556.710.000.151200.41577.850.000.081800.29613.080.000.063600.17718.790.000.037200.10845.630.000.0214400.071200.800.000.01Water Quantity Storage: 1,201 ft3Peak Flow: 0.24 ft3/sWater Quality Storage:Where: P = 0.5inchesRv = 0.0734I = 0.03A = 1.21acresUnimproved Area0Water Quality Storage: 162 ft3 Water Quality Storage162 ft3Total Required Storage 1,201 ft3P(10-yr, 24 hr) 1.7FLOW∆ ELEV FLOWVELOCITYTIME OF FLOW TYPELENGTH (FT)(FT)SLOPE (%)n(FT/S)CONC. (MIN)SHEET FLOW701420.0%0.410--9.0SHALLOW CONC.30051.7%--0.1925.8434.8x34.8y0.24x030y00.270x135y10.239 Linear InterpolationI = the percent impervious cover draining to the facility, in decimalA = total site area draining to the structure, in acres"I" if statementsThese are the volumes that must be mitigatedTime of ConcentrationPre-Developed718.79845.631200.80WQV = Water Quality Volume, in acre-feetP = Water Quality Rainfall Depth, inches (0.5-inches) Rv = the unitless runoff coefficient, Rv = 0.05 + 0.9(I) 528.52534.39542.61556.71577.85613.08403.44432.21458.05486.24501.51512.08Site Detention= Runoff Volume - Discharge Volume(ft3)0.00227.26332.38Total Quantity Total QuantityTotal QuantityTotal QuantityUnimproved AreaGravelLawnTotalsBasin B (10 YR)RUNOFF CALCULATIONSTotal Required Storage:Surface TypeArea (ft2)Area (Acres)Runoff CoefficienFrequency Factor (Cf)C x CfCalculation Value (C') C' x A (Acres)
Input parameters in light blue 100year design storm1,419 0.03 0.20 1.25 0.25 0.25 0.008144799 0.02 0.801.251.001.000.01834350,692 1.16 0.151.250.190.190.21819952,910 1.21 0.24Total QuantityRainfallRainfallRunoff Volume Discharge VolumePeak FlowDuration, tIntensity, i= Cwd x SAj x i x t= d x t=C*I*A(min)(in/hr)(ft3) (ft3) (ft3/sec)0 0.00 0.00 0.00 0.0056.09447.040.001.49104.45653.310.001.09153.61794.980.000.88202.89848.570.000.71252.46902.890.000.60302.18960.150.000.53351.92986.570.000.47401.721010.060.000.42451.571037.220.000.38501.441057.040.000.35551.331073.920.000.33601.241092.280.000.301200.611074.660.000.151800.411083.470.000.103600.221162.750.000.057200.141479.860.000.0314400.102071.800.000.02Water Quantity Storage: 2,072 ft3Peak Flow: 0.49 ft3/sWater Quality Storage:Where: P = 0.5inchesRv = 0.0734I = 0.03A = 1.21acresUnimproved Area0Water Quality Storage: 162 ft3 Water Quality Storage162 ft3Total Required Storage 2,072 ft3P(100-yr, 24 hr) 2.34FLOW∆ ELEV FLOWVELOCITYTIME OF FLOW TYPELENGTH (FT)(FT)SLOPE (%)n(FT/S)CONC. (MIN)SHEET FLOW701420.0%0.410--7.7SHALLOW CONC.30051.7%--0.1925.8433.5x33.5y0.49x030y00.533x135y10.470 Linear InterpolationI = the percent impervious cover draining to the facility, in decimalA = total site area draining to the structure, in acres"I" if statementsThese are the volumes that must be mitigatedTime of ConcentrationPre-Developed1162.751479.862071.80WQV = Water Quality Volume, in acre-feetP = Water Quality Rainfall Depth, inches (0.5-inches) Rv = the unitless runoff coefficient, Rv = 0.05 + 0.9(I) 1037.221057.041073.921092.281074.661083.47794.98848.57902.89960.15986.571010.06Site Detention= Runoff Volume - Discharge Volume(ft3)0.00447.04653.31Total Quantity Total QuantityTotal QuantityTotal QuantityC' x A (Acres)Unimproved AreaGravelLawnTotalsBasin B (100 YR)RUNOFF CALCULATIONSTotal Required Storage:Surface TypeArea (ft2)Area (Acres)Runoff CoefficienFrequency Factor (Cf)C x CfCalculation Value (C')
Input parameters in light blue 10year design storm1,691 0.04 0.20 1.00 0.20 0.20 0.007766689 0.02 0.801.000.800.800.0126551,230 0.03 0.151.000.150.150.0042363,610 0.08 0.02*Input values for Runoff Coefficients (C) from 'Runoff Coefficients' tabTotal QuantityRainfallRainfallRunoff Volume Discharge VolumePeak FlowDuration, tIntensity, i= Cwd x SAj x i x t= d x t=C*I*A(min)(in/hr)(ft3) (ft3) (ft3/sec)0 0.00 0.00 0.00 0.0053.8728.630.000.10102.8341.870.000.07152.2950.820.000.06201.8454.440.000.05251.5657.700.000.04301.3861.250.000.03351.2263.170.000.03401.0964.500.000.03451.0066.570.000.02500.9167.310.000.02550.8468.350.000.02600.7970.120.000.021200.4172.790.000.011800.2977.220.000.013600.1790.540.000.007200.10106.520.000.0014400.07151.250.000.00Water Quantity Storage: 151 ft3Peak Flow: 0.06 ft3/sWater Quality Storage:Where: P = 0.5inchesRv = 0.221I = 0.19A = 0.08acres0Water Quality Storage: 33 ft3 Water Quality Storage33 ft3Total Required Storage 151 ft3P(10-yr, 24 hr) 1.7FLOW∆ ELEV FLOWVELOCITYTIME OF FLOW TYPELENGTH (FT)(FT)SLOPE (%)n(FT/S)CONC. (MIN)SHEET FLOW361.33.6%0.410--10.5SHALLOW CONC.480.6611.4%--0.184.5515.0x15.0y0.06x015y00.056x120y10.045 Linear InterpolationI = the percent impervious cover draining to the facility, in decimalA = total site area draining to the structure, in acresThese are the volumes that must be mitigatedTime of ConcentrationPre-Developed90.54106.52151.25WQV = Water Quality Volume, in acre-feetP = Water Quality Rainfall Depth, inches (0.5-inches) Rv = the unitless runoff coefficient, Rv = 0.05 + 0.9(I) 66.5767.3168.3570.1272.7977.2250.8254.4457.7061.2563.1764.50Site Detention= Runoff Volume - Discharge Volume(ft3)0.0028.6341.87Total Quantity Total QuantityTotal QuantityTotal QuantityC' x A (Acres)Unimproved AreaGravelLawnTotalsBasin C (10-YR)RUNOFF CALCULATIONSTotal Required Storage:Surface TypeArea (ft2)Area (Acres)Runoff CoefficienFrequency Factor (Cf)C x CfCalculation Value (C')
Input parameters in light blue 100year design storm1,691 0.04 0.20 1.25 0.25 0.25 0.009707689 0.02 0.801.251.001.000.0158191,230 0.03 0.151.250.190.190.0052953,610 0.08 0.03*Input values for Runoff Coefficients (C) from 'Runoff Coefficients' tabTotal QuantityRainfallRainfallRunoff Volume Discharge VolumePeak FlowDuration, tIntensity, i= Cwd x SAj x i x t= d x t=C*I*A(min)(in/hr)(ft3) (ft3) (ft3/sec)0 0.00 0.00 0.00 0.0056.0956.310.000.19104.4582.290.000.14153.61100.140.000.11202.89106.890.000.09252.46113.730.000.08302.18120.940.000.07351.92124.270.000.06401.72127.230.000.05451.57130.650.000.05501.44133.140.000.04551.33135.270.000.04601.24137.580.000.041200.61135.360.000.021800.41136.470.000.013600.22146.460.000.017200.14186.400.000.0014400.10260.960.000.00Water Quantity Storage: 261 ft3Peak Flow: 0.09 ft3/sWater Quality Storage:Where: P = 0.5inchesRv = 0.221I = 0.19A = 0.08acres0Water Quality Storage: 33 ft3 Water Quality Storage33 ft3Total Required Storage 261 ft3P(100-yr, 24 hr) 2.34FLOW∆ ELEV FLOWVELOCITYTIME OF FLOW TYPELENGTH (FT)(FT)SLOPE (%)n(FT/S)CONC. (MIN)SHEET FLOW361.33.6%0.410--8.9SHALLOW CONC.510.6611.3%--0.174.9813.9x13.9y0.12x010y00.137x115y10.111 Linear InterpolationI = the percent impervious cover draining to the facility, in decimalA = total site area draining to the structure, in acresThese are the volumes that must be mitigatedTime of ConcentrationPre-Developed146.46186.40260.96WQV = Water Quality Volume, in acre-feetP = Water Quality Rainfall Depth, inches (0.5-inches) Rv = the unitless runoff coefficient, Rv = 0.05 + 0.9(I) 130.65133.14135.27137.58135.36136.47100.14106.89113.73120.94124.27127.23Site Detention= Runoff Volume - Discharge Volume(ft3)0.0056.3182.29Total Quantity Total QuantityTotal QuantityTotal QuantityC' x A (Acres)Unimproved AreaGravelLawnTotalsBasin C (100-YR)RUNOFF CALCULATIONSTotal Required Storage:Surface TypeArea (ft2)Area (Acres)Runoff CoefficienFrequency Factor (Cf)C x CfCalculation Value (C')
Input parameters in light blue 10year design storm1,184 0.03 0.95 1.00 0.95 0.95 0.03- 1,811 0.04 0.20 1.00 0.20 0.20 0.012,843 0.07 0.95 1.00 0.95 0.95 0.067,797 0.18 0.95 1.00 0.95 0.95 0.171,651 0.04 0.15 1.00 0.15 0.15 0.01799 0.02 0.70 1.00 0.70 0.70 0.0150,692 1.16 0.15 1.00 0.15 0.15 0.171,419 0.03 0.20 1.00 0.20 0.20 0.0168,196 1.570.47Rate DischargeLength (ft) Width (ft) (in/hr) (cfs)00.21Total QuantityRainfallRainfallRunoff Volume Discharge VolumePeak FlowDuration, tIntensity, i= Cwd x SAj x i x t= d x t=C*I*A(min)(in/hr)(ft3) (ft3) (ft3/sec)0 0.00 0.00 0.00 0.005 3.87 540.78 62.63 1.8010 2.83 790.90 125.26 1.3215 2.29 959.98 187.89 1.0720 1.84 1028.45 250.52 0.8625 1.56 1089.93 313.16 0.7330 1.38 1157.01 375.79 0.6435 1.22 1193.34 438.42 0.5740 1.09 1218.49 501.05 0.5145 1.00 1257.62 563.68 0.4750 0.91 1271.59 626.31 0.4255 0.84 1291.15 688.94 0.3960 0.79 1324.69 751.57 0.37120 0.41 1374.99 1503.15 0.19180 0.29 1458.84 2254.72 0.14360 0.17 1710.36 4509.44 0.08720 0.10 2012.19 9018.87 0.051440 0.07 2857.31 18037.75 0.03Water Quantity Storage: 781 ft3Peak Flow: 1.80 ft3/sWater Quality Storage:Where: P = 0.5inchesRv = 0.2165I = 0.19 A = 1.57 acresWater Quality Storage: 615 ft3 Water Quality Storage615 ft3Total Required Storage 781 ft3P = Water Quality Rainfall Depth, inches (0.5-inches) RoofAsphaltPaversLawn (Offsite)Gravel (Offsite)Landscape-----I = the percent impervious cover draining to the facility, in decimalA = total site area draining to the structure, in acresThese are the volumes that must be mitigated---------------WQV = Water Quality Volume, in acre-feet776.78781.22754.92717.44Rv = the unitless runoff coefficient, Rv = 0.05 + 0.9(I) 693.94645.28602.21573.12-----(ft3)0.00478.14665.64772.09777.93Total Quantity Total QuantityTotal QuantityTotal QuantitySite Detention= Runoff Volume - Discharge VolumePercolation Discharge Rate:Infiltration AreaC' x A (Acres)ConcreteBasin 1 (10-YR) RUNOFF CALCULATIONSTotal Required Storage:Surface TypeArea (ft2)Area (Acres)Runoff Coefficient (C)*Frequency Factor (Cf)C x CfCalculation Value (C') =(C x Cf) < or = 1Unimproved Area (Offsite)Totals
Input parameters in light blue 100year design storm1,184 0.03 0.95 1.25 1.19 1.00 0.03- 1,811 0.04 0.20 1.25 0.25 0.25 0.012,843 0.07 0.95 1.25 1.19 1.00 0.077,797 0.18 0.95 1.25 1.19 1.00 0.181,651 0.04 0.15 1.25 0.19 0.19 0.01799 0.02 0.70 1.25 0.88 0.88 0.0250,692 1.16 0.15 1.25 0.19 0.19 0.221,419 0.03 0.20 1.25 0.25 0.25 0.0168,196 1.570.53Rate DischargeLength (ft) Width (ft) (in/hr) (cfs)01.190Total QuantityRainfallRainfallRunoff Volume Discharge VolumePeak FlowDuration, tIntensity, i= Cwd x SAj x i x t= d x t=C*I*A(min)(in/hr)(ft3) (ft3) (ft3/sec)0 0.00 0.00 0.00 0.0056.091063.73357.003.55104.451554.55714.002.59153.611891.671071.002.10202.892019.171428.001.68252.462148.431785.001.43302.182284.672142.001.27351.922347.552499.001.12401.722403.452856.001.00451.572468.073213.000.91501.442515.233570.000.84551.332555.413927.000.77601.242599.074284.000.721200.612557.158568.000.361800.412578.1112852.000.243600.222766.7625704.000.137200.143521.3351408.000.0814400.104929.86102816.000.06Water Quantity Storage: 841 ft3Peak Flow: 3.55 ft3/sWater Quality Storage:Where: P = 0.5inchesRv = 0.2165I = 0.19A = 1.57acresWater Quality Storage: 615 ft3 Water Quality Storage615 ft3Total Required Storage 841 ft3I = the percent impervious cover draining to the facility, in decimalA = total site area draining to the structure, in acresThese are the volumes that must be mitigated---------------WQV = Water Quality Volume, in acre-feetP = Water Quality Rainfall Depth, inches (0.5-inches) Rv = the unitless runoff coefficient, Rv = 0.05 + 0.9(I) ------------------------------820.67591.17363.43142.67----------= Runoff Volume - Discharge Volume(ft3)0.00706.73840.55Infiltration AreaTotal Quantity Total QuantityTotal QuantityTotal QuantitySite DetentionPercolation Discharge Rate:LandscapeGravel (Offsite)Lawn (Offsite)Unimproved Area (Offsite)TotalsC' x A (Acres)ConcretePaversAsphaltRoofBasin 1(100-YR)RUNOFF CALCULATIONSTotal Required Storage:Surface TypeArea (ft2)Area (Acres)Runoff Coefficient (C)*Frequency Factor (Cf)C x CfCalculation Value (C') =(C x Cf) < or = 1
Input parameters in light blue 10year design storm1,428 0.03 0.951.000.950.950.0313,196 0.07 0.951.000.950.950.0701,549 0.04 0.701.000.700.700.025240 0.01 0.201.000.200.200.0014,617 0.11 0.151.000.150.150.016689 0.02 0.701.000.700.700.0111,230 0.03 0.151.000.150.150.0041,691 0.04 0.201.000.200.200.00814,640 0.340.17Total QuantityRainfallRainfallRunoff Volume Discharge VolumePeak FlowDuration, tIntensity, i= Cwd x SAj x i x t= d x t=C*I*A(min)(in/hr)(ft3) (ft3) (ft3/sec)0 0.00 0.00 0.00 0.0053.87192.500.000.64102.83281.540.000.47152.29341.730.000.38201.84366.100.000.31251.56387.990.000.26301.38411.870.000.23351.22424.800.000.20401.09433.750.000.18451.00447.680.000.17500.91452.660.000.15550.84459.620.000.14600.79471.560.000.131200.41489.470.000.071800.29519.310.000.053600.17608.850.000.037200.10716.290.000.0214400.071017.140.000.01Water Quantity Storage: 1,017 ft3Peak Flow: 0.44 ft3/sWater Quality Storage:Where: P = 0.5inchesRv = 0.491I = 0.49 A = 0.34 acresWater Quality Storage300 ft3Total Required Storage 1,017 ft3P(10-yr, 24 hr) 1.7FLOW∆ ELEV FLOWVELOCITYTIME OF FLOW TYPELENGTH (FT)(FT)SLOPE (%)n(FT/S)CONC. (MIN)SHEET FLOW2514.0%0.100--2.4SHALLOW CONC.18284.4%--0.34 8.98
11.4x
11.4y 0.44x010y0
0.469x115y1
0.380 Linear InterpolationPaversLandscapeTime of ConcentrationPre-DevelopedGravel (Offsite)Lawn (Offsite)Unimproved Area (Offsite)Site DetentionC' x A (Acres)Roof AreaConcreteBasin 2 (10-YR)RUNOFF CALCULATIONSTotal Required Storage:Surface TypeArea (ft2)Area (Acres)Runoff Coefficient (C)*Frequency Factor (Cf)C x CfCalculation Value (C') =(C x Cf) < or = 1TotalsGravelTotal Quantity Total QuantityTotal QuantityTotal Quantity447.68452.66459.62471.56= Runoff Volume - Discharge Volume(ft3)0.00192.50281.54341.73These are the volumes that
must be mitigated608.85716.291017.14WQV = Water Quality Volume, in acre-feet366.10387.99411.87424.80433.75P = Water Quality Rainfall Depth, inches (0.5-inches) 489.47519.31I = the percent impervious cover draining to the facility, in decimalA = total site area draining to the structure, in acresRv = the unitless runoff coefficient, Rv = 0.05 + 0.9(I)
Input parameters in light blue 100year design storm1,428 0.03 0.951.251.191.000.0333,196 0.07 0.951.251.191.000.0731,549 0.04 0.701.250.880.880.031240 0.01 0.201.250.250.250.0014,617 0.11 0.151.250.190.190.020689 0.02 0.701.250.880.880.0141,230 0.03 0.151.250.190.190.0051,691 0.04 0.201.250.250.250.01014,640 0.340.19Total QuantityRainfallRainfallRunoff Volume Discharge VolumePeak FlowDuration, tIntensity, i= Cwd x SAj x i x t= d x t=C*I*A(min)(in/hr)(ft3) (ft3) (ft3/sec)0 0.00 0.00 0.00 0.0056.09378.660.001.26104.45553.390.000.92153.61673.390.000.75202.89718.780.000.60252.46764.790.000.51302.18813.290.000.45351.92835.670.000.40401.72855.570.000.36451.57878.580.000.33501.44895.370.000.30551.33909.670.000.28601.24925.210.000.261200.61910.290.000.131800.41917.750.000.083600.22984.900.000.057200.141253.510.000.0314400.101754.920.000.02Water Quantity Storage: 1,755 ft3Peak Flow: 0.89 ft3/sWater Quality Storage:Where: P = 0.5inchesRv = 0.491I = 0.49 A = 0.34 acresWater Quality Storage:300 Water Quality Storage300 ft3Total Required Storage 1,755 ft3P (100 yr, 24 hr) 2.34FLOW∆ ELEV FLOWVELOCITYTIME OF FLOW TYPELENGTH (FT)(FT)SLOPE (%)n(FT/S)CONC. (MIN)SHEET FLOW2514.0%0.100--2.1SHALLOW CONC.18284.4%--0.348.9811.1x11.1y0.89x010y00.922x115y10.748 Linear InterpolationA = total site area draining to the structure, in acresThese are the volumes that must be mitigatedTime of ConcentrationPre-Developed1253.511754.92WQV = Water Quality Volume, in acre-feetP = Water Quality Rainfall Depth, inches (0.5-inches) Rv = the unitless runoff coefficient, Rv = 0.05 + 0.9(I) I = the percent impervious cover draining to the facility, in decimal895.37909.67925.21910.29917.75984.90718.78764.79813.29835.67855.57878.58= Runoff Volume - Discharge Volume(ft3)0.00378.66553.39673.39Total Quantity Total QuantityTotal QuantityTotal QuantitySite DetentionGravel (Offsite)Lawn (Offsite)Unimproved Area (Offsite)TotalsC' x A (Acres)Roof AreaConcreteGravelPaversLandscapeBasin 2 (100 YR)RUNOFF CALCULATIONSTotal Required Storage:Surface TypeArea (ft2)Area (Acres)Runoff Coefficient (C)*Frequency Factor (Cf)C x CfCalculation Value (C') =(C x Cf) < or = 11/1
BARDO BOZEMAN
Project # 250389.01/.02 APPENDIX C HYDRAULIC CALCULATIONS HAGGERTY MULTI-FAMILY
Circular Pipe Flow - 96% Fulln0.013ConcreteMannings Roughness Coefficient% Full0.96Partial Flowd12.00inchesPipe DiameterS0.026ft/ftPipe SlopeR0.283ft2Hydraulic RadiusA0.77ft2AreaQ6.11cfsFlow Capacity 2743gpmV7.89fpsVelocity2.00 ft
0.6
0.7854ft2
32.2ft/s25.35 cfs
2.00 ft
0.6
0.0308ft2
32.2ft/s20.21 cfs
Outlet Orifice (Opening)Head Water Depth (h):Discharge Coeff. (Cd):Open Area (A):Open Area (A):Gravity (g):Flow (Q) = C ∙ A ∙ (2 ∙ g ∙ h) ^ (0.5)Gravity (g):Flow (Q) = C ∙ A ∙ (2 ∙ g ∙ h) ^ (0.5)Hydraulic CalculationsOutlet OrificeHead Water Depth (h):Discharge Coeff. (Cd):
Project # 250389.01/.02 APPENDIX D O&M PLAN HAGGERTY MULTI-FAMILY
February 2026 Project No. 250389.02 STORM DRAINAGE FACILITY MAINTENANCE PLAN HAGGERTY MULTI-FAMILY BOZEMAN, MONTANA 59715 OVERVIEW NARRATIVE The purpose of this maintenance plan is to outline the necessary details related to ownership, responsibility, and cleaning schedule for the storm drainage facilities for Haggerty Multi-Family. This plan has been completed in accordance with City of Bozeman Design and Construction Standards, dated October 2024. The site stormwater improvements have been designed with the intent to meet the current City of Bozeman drainage regulations for the entire site to the extent feasible. Specific site information and criteria are described below: OWNERSHIP OF FACILITIES Haggerty Infill LLC Haggerty Infill LLC will own all stormwater facilities which includes the permeable pavers, gravel detention basin, trench drains, manholes, and piping within the site boundary. INSPECTION THRESHOLDS FOR CLEANING Trench Drains/Manholes If sediment fills 60 percent of the sump or comes within 6 inches of a pipe, clean sump with a vacuum. Permeable Pavers If 50% of the joints between blocks are filled with debris, schedule a cleaning.
CLEANING Trench Drains/Manholes To clean grate of structure, remove and dispose of debris clogging the grate. To clean the structure, use vacuum to remove sediment and debris. Permeable Pavers Use a JetVac to clean the joints between pavers. INSPECTION, MAINTENANCE, AND REPLACEMENT SCHEDULE Trench Drains/Manholes • Inspection: Every 6 months and after storm events larger than 0.5 inches of precipitation. • Maintenance: Clean grate of structure and vacuum sediment and debris out of the sump every 5 years or as needed based on inspection. • Design Life/Replacement Schedule: 50 years Permeable Pavers • Inspection: Every 12 months and after storm events larger than 0.5 inches of precipitation. • Design Life/Replacement Schedule: 50 years RESPONSIBLE PARTY Haggerty Infill LLC Haggerty Infill LLC will be responsible for the inspection, maintenance, and replacement of all stormwater facilities located within the project limits. I agree to the above inspection, maintenance, and replacement schedule detailed above. Signature: __________________________________________ Haggerty Infill LLC Representative
Project # 250389.01/.02 APPENDIX E GEOTECHNICAL REPORT HAGGERTY MULTI-FAMILY
UPDATED
GEOTECHNICAL
REPORT
219 Haggerty Lane
(406) 582 -022132 Discovery Dr, Bozeman, MT 59718 www.alliedengineering.com
January 2026
Bozeman, Montana
Civil • Geotechnical • Water Resources • Land Surveying • Construction Services
Corporate Office
32 Discovery Dr.
Bozeman, MT 59718
Ph: (406) 582-0221
www.alliedengineering.com
SAM UEI: LYARYWD1YSZ1 CAGE: IGHU7
January 21, 2026
Haggerty Infill LLC
c/o: Jackson Bruff
402 E. Main Street, Suite 3
Bozeman, MT 59715
Email: jsbruff@gmail.com
RE: Updated Geotechnical Report for 219 Haggerty Lane
Bozeman, Montana
Dear Mr. Bruff:
Enclosed please find our updated geotechnical report for 219 Haggerty Lane, located east of
downtown Bozeman, Montana.
As per our scope of work, this report presents our geotechnical assessment of the project site and
provides recommendations pertaining to foundation design, seismic site classification, allowable
bearing and lateral earth pressures, estimated foundation settlements, wall backfill materials and
compaction recommendations, foundation-related fill materials, utilities, surface and subsurface
drainage, asphalt pavement section materials and design thickness, and general site earthwork.
This report was prepared for use by all associated parties during the planning, design, and
construction phases of this project. It is important that the Design Team and all Contractors
involved with site work are provided with copies of this report, so they are informed of the site
conditions found at our exploration locations and our geotechnical and construction
recommendations.
We appreciate the opportunity to perform these services. Please call if you have any questions.
Sincerely,
Allied Engineering Services, Inc.
____________________________________ ____________________________________
Craig Madson, PE Jessi Ellingsen, EI
President / Geotechnical Engineer Geotechnical Engineer
enc: Updated Geotechnical Report
P:\2022\22-097 219 Haggerty Lane Geotechnical Investigation and Report\05 Design\Geotech\Rewrite - December 2025\Report\22-097 - Cover Letter.docx
i
TABLE OF CONTENTS
TABLE OF CONTENTS ..................................................................................................................................... i
INTRODUCTION ............................................................................................................................................. 1
PROJECT DESCRIPTION AND BACKGROUND ................................................................................................. 1
SCOPE OF WORK ........................................................................................................................................... 1
GEOLOGY ...................................................................................................................................................... 2
EXPLORATIONS AND SUBSURFACE CONDITIONS ......................................................................................... 2
Subsurface Explorations ........................................................................................................................... 2
Subsurface Conditions .............................................................................................................................. 3
Groundwater Conditions .......................................................................................................................... 3
Laboratory Testing .................................................................................................................................... 4
FOUNDATION, SLAB, AND DRAINAGE RECOMMENDATIONS ....................................................................... 4
Seismic Design Factors.............................................................................................................................. 4
Foundation Design .................................................................................................................................... 4
Foundation Support .................................................................................................................................. 4
Design Bearing Pressures ......................................................................................................................... 5
Interior Concrete Slabs ............................................................................................................................. 5
Modulus of Subgrade Reaction Under Slabs ............................................................................................ 6
Lateral Earth Pressures ............................................................................................................................. 6
Foundation Wall Backfill ........................................................................................................................... 6
Subsurface Drainage ................................................................................................................................. 7
Vapor Barrier and Damp-Proofing ............................................................................................................ 7
Surface Drainage Recommendations ....................................................................................................... 7
Exterior Concrete Slabs ............................................................................................................................ 7
FOUNDATION-RELATED FILL MATERIAL RECOMMENDATIONS .................................................................... 8
Excavated Foundation Soils ...................................................................................................................... 8
Sandy (Pit Run) Gravel .............................................................................................................................. 8
Crushed (Road Mix) Gravel ....................................................................................................................... 8
Clean Crushed Rock .................................................................................................................................. 8
FILL PLACEMENT AND COMPACTION ........................................................................................................... 8
PAVEMENT SECTION RECOMMENDATIONS ................................................................................................. 9
GENERAL CONSTRUCTION RECOMMENDATIONS ...................................................................................... 10
Topsoil Stripping and Re-Use .................................................................................................................. 10
Moisture Sensitivity of Fine-Grained Soils .............................................................................................. 10
Support of Utility Lines ........................................................................................................................... 10
Trench Backfill ........................................................................................................................................ 10
Cold/Winter Weather Construction ....................................................................................................... 11
ii
Sediment Control .................................................................................................................................... 11
AESI FUTURE INVOLVEMENT ...................................................................................................................... 11
LIMITATIONS ............................................................................................................................................... 11
REFERENCES ................................................................................................................................................ 13
SUPPLEMENTAL INFORMATION
• List of Tables
o Table 1. Compaction Recommendations (Application vs. Percent Compaction)
o Table 2. Recommended Pavement Section
• List of Figures
o Figure 1 – Vicinity Map
o Figure 2 – Quadrangle Map
o Figure 3 – Test Pit and Borehole Location Map
o Figure 4 – Geology Map
o Figure 5 – Groundwater Map
o Figure 6 – Foundation Detail
• List of Appendices
o Appendix A – Borehole and Test Pit Logs
o Appendix B – Laboratory Testing Results
o Appendix C – Limitations of Your Geotechnical Report
www.alliedengineering.com
INTRODUCTION
This report and attachments provide our geotechnical recommendations for the future development
proposed at 219 Haggerty Lane on the east side of Bozeman, Montana. The information contained
herein is based on an investigation of the property’s topographical and subsurface conditions, a review
of geologic maps and literature for the project area, and our experience with other similar
developments in the area. The purpose of this report is to provide a description of the site’s soil and
groundwater conditions as well as recommendations for the design and construction of future
developments proposed for the property.
PROJECT DESCRIPTION AND BACKGROUND
The 0.468-acre, rectangular-shaped property is located on the southwest side of Haggerty Lane
approximately 0.12 miles south of the intersection with East Main Street. The property is situated in the
Southwest One-Quarter of Section 8, Township 2 South, Range 6 East, Principal Meridian Montana,
Gallatin County, Montana. See Figures 1 and 2 for site location maps.
The lot is currently undeveloped with grades dropping to the northeast at approximately five percent.
The property is bound to the northwest by a commercial office building, the northeast by Haggerty Lane,
the southeast by a commercial condominium building, and the southwest by the City of Bozeman
Softball Complex. Site vegetation consists primarily of native grasses with a few large trees near the
southeast corner of the property.
We originally completed a geotechnical report for this property (for a different client) in July 2022 when
the proposed improvements included a single 5-story building. Two 30-foot boreholes were completed
as part of the original investigation. We understand that plans for development on the property have
since changed, necessitating a rewrite of the previous report that is tailored toward the new
development. Based on the latest plans, the proposed improvements now include two 3-story
townhouse buildings supported by slab-on-grade foundations. One additional test pit was completed on
the northeast side of the property as part of the additional investigation (see Figure 3 for details). A
monitor well was installed to a depth of 9.0 feet in the test pit to allow for future groundwater
monitoring.
SCOPE OF WORK
Our Scope of Services for this project included:
Review of previous geotechnical work, geology maps, site plans, and other site information.
Completion of one additional test pit within the proposed development site. The locations of all
subsurface explorations (including the previous 2 boreholes) are provided in Figure 3.
Installation of one monitoring well to allow for future groundwater monitoring (by Sanbell).
Laboratory testing of select samples from the test pit exploration.
Foundation support recommendations and allowable bearing criteria.
Associated anticipated settlements.
Haggerty Infill LLC
January 21, 2026
Updated Geotechnical Report – 219 Haggerty Lane
Project No. 22-097.01
32 Discovery Drive . Bozeman, Montana 59718 . Ph: (406) 582-0221 . Fax: (406) 582-5770 Page 2
Minimum foundation depth for frost protection.
Lateral earth pressures for cantilevered and braced wall conditions.
Site-specific seismic classification.
Surface and subsurface drainage recommendations.
Backfill material and compaction recommendations.
Asphalt pavement section materials and design thickness.
Interior/exterior slab support.
General site earthwork, utilities, and construction recommendations.
The results of the above scope of work are summarized in this geotechnical report. The purpose of the
report is to inform the Owner, Builder, Engineer, and Architect of the subsurface conditions
encountered in our explorations; and to present geotechnical recommendations for consideration and
implementation during the planning, design, and construction of the proposed improvements.
GEOLOGY
The geologic map for the area prepared by Lonn and English in 2002 indicates the site is underlain at
depth by the Sixmile Creek Formation, gravelly facies (Tscg). An excerpt of this mapping is provided on
Figure 4. Tscg can be described as, “predominantly light brown to light gray, poorly stratified, poorly
sorted tuffaceous siltstone containing 10 to 50 percent fluvial channel conglomerates”. Generally, this
material is overlain by younger fluvial deposits consisting of layers of silt, clay, sand, and some gravel.
EXPLORATIONS AND SUBSURFACE CONDITIONS
Subsurface Explorations
Subsurface conditions were investigated on June 27 and 28, 2022 and December 16, 2025, under the
directions of Jessi Ellingsen, EI, a staff geotechnical engineer with Allied Engineering Services. Two
boreholes were originally completed on the property using a Mobile B-61 truck mounted drill rig
provided by O’Keefe Drilling of Butte, Montana. One additional test pit exploration was completed in
December of 2025 using a CAT 305 Mini Excavator provided by ND Sitework. The boreholes and test pit
were spatially situated across the lot to provide coverage of the proposed improvements.
During drilling, soil and subsurface moisture conditions were visually characterized, measured, and
logged using split-spoon samples taken at regular intervals. Blow counts noted on the borehole logs
attached consist of the blows required to drive a 2-inch O.D. split spoon sampler in three, 6-inch
increments using a 140-pound hammer dropped 30 inches. The final 12 inches of driving are added
together and recorded as the blow counts (N). The blow counts are used to evaluate the consistency,
density, and shear strength of the soil. Blow counts of more than 50 in any 6-inch increment is deemed
as sampler refusal. All blow counts provided on the logs are uncorrected for overburden pressures.
During the test pit excavation, the relative densities of the exposed soil profiles were estimated based
on the ease or difficulty of digging, probing of the test pit walls, and the overall stability of the
completed excavations.
Copies of our borehole and test pit logs are provided in Appendix A. The logs provide assorted field
information, such as soil depths and descriptions, groundwater conditions, relative density data, and a
sketch of the soil stratigraphy. Please be aware that the detail provided in the logs cannot be
summarized in a paragraph; therefore, it is important to review the logs in conjunction with this report.
Haggerty Infill LLC
January 21, 2026
Updated Geotechnical Report – 219 Haggerty Lane
Project No. 22-097.01
32 Discovery Drive . Bozeman, Montana 59718 . Ph: (406) 582-0221 . Fax: (406) 582-5770 Page 3
Following completion of the fieldwork, the borehole and test pit locations were backfilled and cleaned
up to the extent possible. Each was staked with a wooden lath that identified it accordingly.
Subsurface Conditions
Soil conditions across the site generally consist of organic topsoil overlying variable, alternating Tertiary-
aged layers of sandy silt/clay, sand, and clayey gravel.
In the boreholes completed back in 2022, we encountered approximately 2.0 feet of topsoil overlying
stiff to hard, brown, moist, sandy clay. The sandy clay deposits extended to depths of 4.0 to 9.0 feet and
were underlain by medium dense to dense, brown, wet, clayey gravel with sand and abundant 1.5-inch
minus rock fragments. The wet clayey gravel extended to depths of 12.0 to 14.0 feet. Below the wet
clayey gravel in BH-1, we encountered wet clayey sand that extended from 14.0 to 19.0 feet. This clayey
sand layer was not present in BH-2. Below the wet, clayey gravel and/or wet clayey sand (beginning at
depths of 12.0 to 19.0 feet) soil conditions transitioned to stiff to hard, brown, moist, sandy clay.
Atterberg Limits testing of the sandy clay from BH-2 showed that it was marginally fat. The sandy clay
extended to the bottom of both boreholes at a depth of 31.0 feet. No random fill was encountered in
the borehole explorations (located in the center of the lot).
In the test pit exploration completed near the front edge of the lot (adjacent Haggerty Lane), we
encountered 0.5 feet of topsoil overlying dark brown, very stiff, sandy clay with scattered 8-inch-minus
gravels and cobbles. It appeared this layer of mixed clay with gravel may be random fill from previous
construction of Haggerty Lane. Below the fill (from 2.5 to 3.5 feet), we found a 1.0-foot-thick layer of
loose, rusty brown, very moist, clean sand. At 3.5 feet in depth, the material transitioned to medium
dense, very moist to wet, clayey sandy gravel with abundant 8-inch-minus sub-rounded cobbles and
scattered 18-inch boulders. We encountered a perched water table in this gravel layer (from 5.0 to 7.0
feet). At 7.0 feet, soil conditions transitioned to stiff, brown, very moist, silty sandy clay. This clay layer
appears to be creating the perched water table in the overlying gravel layer. The silty sandy clay
extended to the bottom of the test pit at 9.0 feet.
Any random fill that is encountered during construction should be removed from under the building
foundation footprint and in all exterior areas that will receive asphalt surfacing, concrete slabs, or
embankment fill in order to avoid undesirable settlements.
Groundwater Conditions
At the time of our original explorations in late June 2022, a perched groundwater table was encountered
from 11.0 to 19.0 feet in BH-1 and 10.3 to 12.0 feet in BH-2. When we dug the test pit on the lower side
of the lot in mid-December 2025, we found the perched water table from 5.0 to 7.0 feet. We suspect the
perched water table sits on or within the native clayey gravel and native clayey sand layers and is
underlain by less pervious sandy clay.
Note that groundwater levels in the valley are generally highest in the late spring to early summer
(following the spring melt) and can also rise during irrigation season in July, August, and September. At
this site, we suspect perched groundwater zones exist throughout the year but may become more
prevalent during the melt.
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January 21, 2026
Updated Geotechnical Report – 219 Haggerty Lane
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Laboratory Testing
Sack samples were taken from the explorations for moisture content testing and Atterberg Limit testing,
(in accordance with ASTM D2216 and ASTM D4318, respectively). All laboratory results are provided in
Appendix B.
Four Atterberg Limit tests were performed on select sack samples (BH-1 from 4.0 to 6.0 feet, BH-1 from
7.0 to 9.0 feet, BH-2 from 12.0 to 14.0 feet, and TP-1 at 8.0 feet). The testing indicated that the upper
sandy clay (above the clayey gravel layer) is a lean clay while the deeper sandy clay (below the clayey
gravel layer) is more plastic with one sample testing as marginally fat. Fat clays can be problematic due
to the potential for shrink and swell with moisture changes which can impact overlying foundations and
slabs. In this case, given the depth to the fat clay (about 12 feet), and its already elevated moisture
content, we do not anticipate issues.
FOUNDATION, SLAB, AND DRAINAGE RECOMMENDATIONS
Seismic Design Factors
Bozeman lies within a seismically sensitive area and as a result, the buildings will need to be structurally
designed according to the appropriate earthquake loading parameters. Based on our on-site
explorations and knowledge of the underlying geology, the seismic site class for this project should be
Site Class D if using ASCE 7-16 for design or the Default Site Class if using ASCE 7-22 for design.
Site-specific seismic loading and response spectrum parameters can be obtained from a web-based
platform provided by the USGS Earthquake Hazards Program. The link to the web page is as follows:
https://earthquake.usgs.gov/hazards/designmaps/ where the user is directed to three different
interfaces that can be used to obtain seismic information. The user will need to specify the design code
reference document (ASCE 7-16 or ASCE 7-22), site soil classification (see above), risk category, and site
location using GPS coordinates. Please recognize that the site soil classification varies based on the
design code reference document being used (ASCE 7-16 or ASCE 7-22).
Foundation Design
We understand the buildings will be supported on traditional slab-on-grade foundations with frost walls
and footings. Due to the dropping grade across the lot, it is possible the south end of the structure may
be partially buried.
Any random fill is that is encountered should be removed from under building foundation footprints and
in all exterior areas that will receive asphalt surfacing or concrete slabs in order to avoid undesirable
settlements. For frost protection, the bottom of exterior footings should bear at least 4.0 feet below the
lowest adjacent exterior finished grade.
Foundation Support
As noted earlier, we encountered some variability in the soils found at the site, which can lead to the
potential for some non-uniform settlements under typical foundation loads, particularly under multi-
story structures. For this reason, we recommend mass over-excavating and supporting the
foundations on a 3.0-foot-thick section of geogrid-reinforced, compacted structural fill. This will
provide a uniform bearing surface and help distribute the load under foundations which should
consequently minimize the risk of differential settlement.
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January 21, 2026
Updated Geotechnical Report – 219 Haggerty Lane
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The over-excavation should extend outward from the edge of footings a minimum of 3.0 feet to ensure
proper load transfer. It should also encompass exterior elements such as staircases, roof overhangs,
patios, etc.
Prior to the placement of structural fill, the native subgrade should be compacted to a dense, unyielding
condition and covered with an 8-ounce nonwoven geotextile fabric (e.g., Mirafi 180N). Any soft and/or
wet spots identified in the subgrade should be completely removed and replaced with compacted
granular structural fill. We ask that we be involved with the foundation excavation to view the subgrade
soils prior to placing fabric, geogrid, and structural fill.
The 3.0-foot section of structural fill should be reinforced with three layers of geogrid (Tensar HX5.5)
at 12-inch vertical spacings. The first layer of geogrid should be placed directly on top of the nonwoven
fabric followed by the first 12 inches of compacted structural fill (1.5-inch-minus crushed road mix
gravel). Overlap all geogrid seams by a minimum of 2.0 feet and zip-tie or wire-tie together.
Structural fill within the geogrid-reinforced section under foundations should consist exclusively of 1.5-
inch-minus crushed road mix gravel to ensure proper interlock with the grid. If additional structural fill is
needed below the geogrid-reinforced section to build up to footing grade, it may consist of 3-inch-minus
pit run gravel. The additional structural fill (if needed) does not require geogrid-reinforcement.
Structural fill should be placed in thin horizontal lifts and compacted to at least 98 percent of its
Standard Proctor density per ASTM D698.
Please refer to Figure 6 for a detail showing our foundation recommendations.
Note that it may also be possible to chase the material directly from under footings rather than
excavating the entirety of the building footprint. In that case, we recommend extending the horizontal
extents of the over-excavation to 3.0 feet beyond edge of footing (all sides) as measured at the bottom
of the over-excavation. However, depending on the number of interior footings, this may not be a cost
effective option. This might also be a good reason to consider utilizing a crawlspace foundation, which
would eliminate the cost of bringing structural fill up throughout the interior footprint of the building.
Design Bearing Pressures
An appropriate bearing pressure for design assuming our recommendations are followed is 2,000
pounds per square foot (psf). Total settlements are estimated to be under one inch with minimal
differential settlements, assuming continuous strip footings that are 3.0 feet wide or less. Allowable
bearing pressures during earthquakes may be increased by 50 percent.
Interior Concrete Slabs
The interior slab of the building(s) shall be underlain by at least 6 inches of clean crushed rock overlying
granular structural fill used to build up from the geogrid-reinforced section at footing grade. If footings
are chased individually, we recommend a minimum of 6 inches of crushed drainage rock and 12 inches
of structural fill under lightly loaded interior slabs.
Structural fill under the interior of the building should be placed in thin uniform lifts and compacted to
at least 98 percent of its Standard Proctor Density. Clean crushed rock should be vibratory compacted to
a dense, unyielding condition using a large roller.
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Updated Geotechnical Report – 219 Haggerty Lane
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Modulus of Subgrade Reaction Under Slabs
Assuming our interior slab support recommendations are followed, the subgrade reaction modulus (k)
can be assumed to be 200 pounds per cubic inch (pci). This design value assumes the slab will be
underlain by at least 6 inches of clean crushed rock overlying compacted granular structural fill as noted
above.
Lateral Earth Pressures
All foundation walls that will be fixed at the top prior to the placement of backfill should be designed for
an “at rest” equivalent fluid pressure of 60 pounds per cubic foot (pcf). In contrast, cantilevered
retaining walls may be designed for a lower, “active” equivalent fluid pressure of 45 pcf, provided either
some slight outward rotation of the wall is acceptable upon backfilling, or the wall is constructed in such
a way that accommodates the expected rotation. These “at rest” and “active” design values are only
applicable for walls that will have backfill slopes of less than ten percent and will not be externally
loaded by surface pressures applied above and/or behind the wall. These lateral earth pressures also
assume proper subsurface drainage provisions (e.g., footing drains) are installed to prevent the
development of hydrostatic pressures (for any retaining wall applications or buried portions of the
foundation wall).
Lateral forces from wind, earthquakes, and earth pressures on the opposite side of the structure will be
resisted by passive earth pressure against the buried portion of the foundation wall and by friction at
the bottom of the footing. Passive earth pressures in compacted backfill should be assumed to have an
equivalent fluid pressure of 280 pcf, while a coefficient of friction of 0.35 should be used between cast-
in-place concrete and the granular structural fill. Actual footing loads (not factored or allowable loads)
should be used for calculating frictional resistance to sliding along the base of the footing. Please be
aware that the friction coefficient has no built-in factor of safety; therefore, an appropriate safety factor
should be selected and used in all subsequent calculations for each load case.
The lateral earth pressures summarized above are for static conditions and should be factored
accordingly to represent seismic conditions. We recommend adding an additional 15 pcf of equivalent
fluid pressure to the static “active” and “at-rest” cases to represent the seismic component. The seismic
component of the lateral earth pressure may be assumed to be an inverted triangular pressure
distribution with the resultant located at one third H from the top of the wall where H is the height of
the wall.
Foundation Wall Backfill
Exterior wall backfill can consist of any excavated foundation soil, other than topsoil, provided it is not
overly moist, highly plastic, or too rocky in composition. Interior foundation wall backfill should consist
exclusively of import structural fill. The native soils may require drying to re-use as exterior backfill.
All select backfill materials should be placed in multiple thin lifts and properly compacted to the
appropriate design specification. Exterior wall backfill should be compacted to 95 percent of its Standard
Proctor Density, while structural fill placed under footings and in the interior of the building should be
compacted to 98 percent of ASTM D698. Foundation walls intended to be braced should not be
backfilled until the bracing (such as floor joists) is in place to prevent unintended rotation/deflection of
the wall. To prevent damaging foundation walls during the backfilling process, only hand-operated
compaction equipment is recommended within 3.0 feet of walls that are not buried on both sides. To
Haggerty Infill LLC
January 21, 2026
Updated Geotechnical Report – 219 Haggerty Lane
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minimize the potential for future settlement problems, the level of care (with respect to the selection of
dry backfill materials and the compactive effort that is used) should be increased significantly in those
areas that will receive concrete/asphalt surfacing or that will support a retaining wall. Finally, the re-use
of topsoil as backfill should be limited to the uppermost four to six inches in landscaped areas.
Subsurface Drainage
For slab-on-grade foundations, perimeter footing drains are not necessary unless the exterior grade will
extend above the top of slab (for example, if there was a buried parking garage). However, footing
drains should be installed behind crawlspace and basement walls. Footing drains should consist of 4-inch
perforated PE pipe bedded in crushed rock and completely wrapped in a nonwoven drainage fabric (e.g.,
Mirafi 180N or equivalent). These drains should either daylight to the ground surface or be routed to a
sump with a pump.
Vapor Barrier and Damp-Proofing
To control moisture vapor, we recommend installing a heavy-duty vapor barrier directly under interior
slabs. We recommend a vapor barrier with a water vapor transmission rate of 0.006 or lower as
established by ASTM E96, such as a Stego 15-mil Vapor Barrier. The vapor barrier should be installed as
per the manufacturer recommendations and ASTM E1643, ensuring it is properly attached to
footings/walls and sealed at the seams.
Buried foundation walls should be damp-proofed with an acceptable commercial product as per the
requirements of the International Building Code (IBC 2024). Basement walls should be waterproofed.
Surface Drainage Recommendations
No water should be allowed to accumulate against or flow along any exposed foundation walls.
Concrete or asphalt surfacing that abuts the foundation should be designed with a minimum grade of 2
percent away from the structure, and adjacent landscaped areas should have a slope of at least 5
percent within 10 feet of the wall (see the IBC building codes). To further reduce the potential for
moisture infiltration along foundation walls, backfill materials should be well-compacted and the upper
4 to 6 inches of backfill should consist of low permeability topsoil. Except for the locations that will be
surfaced by concrete or asphalt, finished grades next to foundation walls should be set no less than 6
inches below the top of the sill plate.
We suggest caution in utilizing retention ponds intended to infiltrate storm drainage. The native soils are
not conducive to infiltration. If a retention pond with infiltration is used, we suggest an overflow to
route excess stormwater that cannot infiltrate.
Exterior Concrete Slabs
Lightly loaded exterior concrete slabs should be supported by a minimum of 6 inches of clean crushed
rock overlying 6 inches of granular structural fill. Depending on site grading, the gravel section will either
bear on non-organic, native soils or on embankment fill material that is placed above the stripped
subgrade surface to raise design elevations.
Traffic loaded exterior slabs should be underlain by a minimum of 6 inches of clean crushed rock and 18
inches of granular structural fill placed over non-organic, compacted/unyielding subgrade.
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Prior to placing any embankment fill or structural fill, both of which must be adequately compacted, the
subgrade surface should be proof-rolled to confirm its stability. If any soft or wet areas are identified,
they should be over-excavated and replaced with compacted structural fill.
FOUNDATION-RELATED FILL MATERIAL RECOMMENDATIONS
Excavated Foundation Soils
All topsoil should be stripped and stockpiled for re-use during site reclamation. On-site soils suitable for
re-use as site fill or backfill should be separated from wet, rocky, or otherwise unsuitable soils during
excavation. The suitability of the non-organic excavated soils will depend on their rockiness, plasticity,
natural moisture content, and ability to be re-compacted. The driest soils containing an even mixture of
soil matrix and smaller rock fragments should be selected for use as compacted fill, while the wettest
and rockiest soils should either be hauled off-site or used for general site grading in non-critical
locations. Depending on the time of year, some of the native soil that is excavated may be wet of
optimum and will require drying prior to re-use. This may necessitate the import of dry fill material if
work is conducted during the wet or winter season when drying is not an option.
Sandy (Pit Run) Gravel
Sandy (pit run) gravel is a granular structural fill alternative for placement under exterior slabs,
pavements, and behind foundation walls. This material shall be non-plastic, well-graded, mixture of
clean sand and gravel with 100 percent of its fragments passing a 3-inch screen and less than 10 percent
of its particles (by weight) finer than the No. 200 sieve. In addition to these material and gradation
recommendations, it should meet all other applicable specifications as presented in Section 02234 of
the Montana Public Works Standard Specifications (MPWSS) for uncrushed, sub-base course gravel.
Crushed (Road Mix) Gravel
Crushed (road mix) gravel is another granular structural fill alternative for placement under and/or
behind footings, slabs, and walls. This material shall be non-plastic, well-graded, mixture of clean sand
and gravel that is processed (crushed) such that 100 percent of its fragments pass a 1.5-inch screen and
less than 5 percent of its particles (by weight) are finer than the No. 200 sieve. In addition, it should
meet all other specifications as presented in Section 02235 of the MPWSS for crushed, base course
gravel. Note that only 1.5-inch-minus crushed road mix gravel should be used within the geogrid
reinforced section to ensure proper interlock.
Clean Crushed Rock
The primary uses for clean crushed rock include placement under concrete slabs and behind
foundation/retaining walls for drainage-related purposes. Crushed rock shall consist of a clean
assortment of angular fragments with 100 percent passing a one-inch screen and less than 1 percent (by
weight) finer than the No. 100 sieve. Over 50 percent of the rock particles must have fractured faces.
FILL PLACEMENT AND COMPACTION
All fill materials should be placed in multiple thin, uniform, horizontal lifts and compacted to an
unyielding condition. The “loose” thickness of each layer of fill prior to compaction should not exceed 9
inches for self-propelled rollers, 6 inches for remote-controlled trench rollers, and 4 inches for plate
compactors. The moisture content of any fill material to be compacted should be within 2 percent of its
optimum value.
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January 21, 2026
Updated Geotechnical Report – 219 Haggerty Lane
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Special attention must be paid to the proper compaction of structural fill materials along the edges and
in the corners of the foundation excavation. These areas are usually “tight and confined” and, as a
result, cannot be adequately compacted with large equipment. There are two options available for
dealing with this issue. Either small compactors must be used that are able to “hug” the side of the
excavation or the limits of the excavation must be increased such that compaction of the entire
minimum width of structural fill can be achieved with larger equipment.
Table 1 provides our compaction recommendations for general site applications. These
recommendations apply to all fill materials and are presented as a percentage of the maximum dry
density of the material being placed as defined by ASTM D698. A common misconception is that clean
crushed rock does not require compaction. However, this material does require compaction with a
vibratory plate or smooth drum roller.
Table 1. Compaction Recommendations (Application vs. Percent Compaction)
APPLICATION PERCENT COMPACTION
Structural Fill Under Footings and Interior Slabs 98
Structural Fill Used for Interior Foundation Wall Backfill 98
Exterior Foundation Wall Backfill and Retaining Wall Backfill 95
Structural and Embankment Fill Under Exterior Slabs and Pavements
95
Trench Backfill under Paved Areas and Concrete Slabs 95
Asphalt Pavement (Rice Density) 93
Trench Backfill and Site Grading in Non-Critical, Landscaped Areas 92
Clean Crushed Rock N/A - Vibratory Compaction
PAVEMENT SECTION RECOMMENDATIONS
Assuming the subgrade soil is dry and stable (i.e., the upper 8 inches of native soil can be compacted to
95 percent of ASTM D698), we recommend the pavement section outlined in Table 2.
Please recognize that this section is only applicable to stable subgrade conditions (no rutting,
deflecting, etc). If the subgrade is wet of optimum, it will need to be scarified, dried, and re-worked to
achieve adequate compaction to a stable condition prior to placing sub-base gravel. Soft spots should be
removed and replaced with compacted structural fill. Fabric shall be added if widespread soft
conditions are found as approved by the Engineer.
Table 2. Recommended Pavement Section
MATERIAL COMPACTED THICKNESS (IN)
Asphalt 3
Base Course Gravel 6
Sub-Base Course Gravel 15
315 lb. Woven Geotextile Fabric (Mirafi 600X) Only if Subgrade Conditions are Soft
Stable Subgrade Soils (Less Topsoil) Upper 8 inches compacted to 95%
TOTAL SECTION DESIGN THICKNESS 24
Should widespread moderately unstable subgrade conditions (minor rutting and deflecting, very moist
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subgrade, etc.) be found across the site, we should be notified so that we can analyze the situation and
modify our recommendations if needed. We suggest incorporating a bid item within the contract
documents in the event unstable subgrade conditions are encountered. We should be retained during
the construction of parking areas to evaluate the severity of any unstable conditions encountered and
the use of higher strength fabrics or increasing the sub-base section.
The sub-base and base course materials that comprise the granular parts of the pavement section shall
consist of 3-inch-minus uncrushed sandy (pit run) gravel and 1.5-inch-minus crushed (road mix) gravel,
respectively. Both gravel courses shall meet the material and gradation specifications presented in
MPWSS, Sections 02234 and 02235. Under normal circumstances, the gravel products should be placed
in lifts not exceeding 12 inches in thickness (depending on the size of the compactor) and compacted to
at least 95 percent of the maximum dry density as defined in ASTM D698.
GENERAL CONSTRUCTION RECOMMENDATIONS
Topsoil Stripping and Re-Use
The site is generally covered by 0.5 to 2.0 feet of organic silt/clay topsoil. All organic soils must be
adequately stripped from within the building foundation footprints and in all exterior areas that will
receive asphalt surfacing, concrete slabs, or embankment fills. Final site grading (in landscape areas) and
the reclamation of the disturbed construction areas are the only recommended re-uses of this organic
material.
Moisture Sensitivity of Fine-Grained Soils
The fine-grained soils (silt/clay) that underlie the site are moisture-sensitive materials that can be
problematic during construction. Some drying and re-working of the material may be required to enable
the soils to be workable and suitable for earthwork construction. Assuming the materials can be
properly dried, these soils should be workable and suitable for earthwork construction. However, with
only minor increases in moisture content, compaction of these soils can be difficult until they are
adequately dried. The air drying of fine-grained soils requires time, warm weather, and often
scarification. For this reason, exposed soils should be protected against precipitation and infiltration.
Excavated and fill surfaces should never be left in a rough condition with undrained depressions. In
addition to becoming hard to compact in wet conditions, fine-grained soils are susceptible to erosion
and frost heave.
Support of Utility Lines
Exterior utility lines (water, sewer, and dry utilities) may require Type 2 bedding for support. We
recommend a bid item be included in case Type 2 bedding is deemed necessary by the Engineer. We
suggest proper bedding of all utilities following the specifications found in the Montana Public Works
Standard Specifications.
Trench Backfill
Trench backfill can consist of any native material (except materials containing significant organics) that is
not overly wet or rocky. Due to the presence of perched groundwater tables in places, we recommend
that a bid item be included that allows the import of backfill material where needed. We recommend
that trench backfill be compacted to a minimum of 95 percent of ASTM D698 under pavement/slab
areas and 92 percent in landscaped areas.
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Updated Geotechnical Report – 219 Haggerty Lane
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Cold/Winter Weather Construction
If earthwork construction will occur during the cold/winter weather season, the Contractor shall take all
necessary precautions to prevent the soils from freezing and/or from being contaminated with snow.
Exposed subgrade and fill materials (under footings, slabs, walls, and pavements) should be adequately
covered with concrete insulation blankets to prevent frost penetration and to protect them from snow.
All soils that are used for fill under/around foundation components or pavements and slabs should be
relatively dry, free of intermixed snow and frozen clods, and must not be placed when it is snowing. Fill
materials or foundations should not be placed over frozen soils, which may be in a “frost-heaved
condition”, or over layers of snow.
When earthwork proceeds during non-optimal times of the year, we recommend that it be performed
expeditiously to minimize the amount of time that the foundation excavation is open and exposed to
the elements. In addition, positive drainage must be established away from the excavation to prevent
the entry of surface water runoff and the saturation of the underlying soils. Please be aware that
carelessness with respect to any of the above-referenced items can potentially lead to foundation
settlement problems in the spring when the frost thaws and/or the snow melts. Finally, cold weather
concrete practices and methods should be implemented when conditions dictate.
Sediment Control
Prior to beginning any earthwork construction at the site, adequate sediment control measures must be
in place to prevent disturbed soils/sediment from being carried down slope and off the site via surface
water runoff. According to Montana State Law, all surface waters must be fully protected from the
introduction of sediment by construction-related activities. Sediment protection barriers will need to be
placed at all established drainages, waterways, ponds, wetlands, storm water catch basins, etc., that lie
within or adjacent to the project area. In addition to protecting these elements, we also believe it is a
responsible practice to install a continuous barrier along the down slope side of the construction limits,
especially on sloping sites. This minimal level of effort will help keep disturbed soils as close to the
source area as possible and prevent them from being washed off the property.
AESI FUTURE INVOLVEMENT
We suggest that we be retained during design and construction to ensure that the recommendations
provided herein are properly implemented. We ask that we be allowed to view the foundation
excavation prior to placing fabric, geogrid, and structural fill.
LIMITATIONS
This report provides our geotechnical-related recommendations for 219 Haggerty Lane located in
Bozeman, Montana. Please be advised that this report is only applicable for the above-referenced
project and shall not be used for other nearby projects. Since geotechnical-related conditions can
change in a short distance, we recommend that all properties be evaluated on a site-specific basis.
The recommendations presented herein are primarily based on observation and evaluation of the site’s
surface and subsurface conditions, along with review and interpretation of geologic maps, and previous
engineering experience within the project area. If during earthwork construction, soil and groundwater
conditions are found to be inconsistent with those described in the report, we should be advised
immediately so the situation can be analyzed, and recommendations can be modified as needed.
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January 21, 2026
Updated Geotechnical Report – 219 Haggerty Lane
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Please be aware that our work does not constitute a guarantee against geotechnical issues arising from
a multitude of potential issues ranging from poorly performed earthwork to the presence of soil
conditions that were not observed or interpreted by our explorations or research.
All individuals associated with this project should consult this report during the planning, design, and
construction of the site improvements. It should be made available to other parties for information on
factual data only and not as a warranty of actual subsurface conditions such as those interpreted herein.
We appreciate the opportunity to perform our geotechnical services. Please call if you have questions.
Sincerely,
Allied Engineering Services, Inc.
Craig Madson, PE
President / Geotechnical Engineer
Jessi Ellingsen, EI
Geotechnical Engineer
Haggerty Infill LLC
January 21, 2026
Updated Geotechnical Report – 219 Haggerty Lane
Project No. 22-097.01
32 Discovery Drive . Bozeman, Montana 59718 . Ph: (406) 582-0221 . Fax: (406) 582-5770 Page 13
REFERENCES
1. American Society of Civil Engineers, 2016. “Minimum Design Loads and Associated Criteria for
Buildings and Other Structures” ASCE/SEI 7-16.
2. American Society of Civil Engineers, 2022. “Minimum Design Loads and Associated Criteria for
Buildings and Other Structures” ASCE/SEI 7-22.
3. American Society of Testing and Materials, 2024. “Standard Practice for Selection, Design,
Installation, and Inspection of Water Vapor Retarders Used in Contact with Earth or Granular Fill
Under Concrete Slabs” ASTM E1643.
4. American Society of Testing and Materials, 2021. “Standard Test Methods for Laboratory
Compaction Characteristics of Soil Using Standard Effort (12,400 ft-lb)” ASTM D698.
5. American Society of Testing and Materials, 2019. “Standard Test Methods for Laboratory
Determination of Water (Moisture) Content of Soil and Rock by Mass” ASTM D2216.
6. American Society of Testing and Materials, 2018. “Standard Test Methods for Liquid Limit, Plastic
Limit, and Plasticity Index of Soils” ASTM D4318.
7. American Society of Testing and Materials, 2017. “Standard Test Methods for Water Vapor
Transmission of Materials” ASTM E96.
8. International Code Council, 2024. “International Building Code”.
9. Lonn, J. and English, A., 2002. “Preliminary Geologic Map of the Eastern Part of the Gallatin Valley
Montana”, MBMG Open-File Report 457.
10. Montana Contractors Association, April 2021. “Montana Public Works Standard Specifications”
Seventh Edition.
11. Slagle, S.E., 1995. “Geohydrologic Conditions and Land Use in the Gallatin Valley, Southwestern
Montana, 1992-93”, USGS Water-Resources Investigations Report 95-4034.
P:\2022\22-097 219 Haggerty Lane Geotechnical Investigation and Report\05 Design\Geotech\Rewrite - December 2025\Report\22-097.01 -
219 Haggerty Lane - Geotechnical Report.docx
LIST OF FIGURES
FFiigguurree 11 –– VViicciinniittyy MMaapp
FFiigguurree 22 –– QQuuaaddrraannggllee MMaapp
FFiigguurree 33 –– TTeesstt PPiitt && BBoorreehhoollee LLooccaattiioonn MMaapp
FFiigguurree 44 –– GGeeoollooggyy MMaapp
FFiigguurree 55 –– GGrroouunnddwwaatteerr MMaapp
FFiigguurree 66 –– FFoouunnddaattiioonn DDeettaaiill
FIGURECivil Engineering
Geotechnical EngineeringLand Surveying
32 DISCOVERY DRIVE . BOZEMAN, MT 59718PHONE (406) 582-0221 . FAX (406) 582-5770www.alliedengineering.com
219 HAGGERTY LANE
VICINITY MAP
BOZEMAN, MONTANA
1
N
FIGURECivil Engineering
Geotechnical EngineeringLand Surveying
32 DISCOVERY DRIVE . BOZEMAN, MT 59718PHONE (406) 582-0221 . FAX (406) 582-5770www.alliedengineering.com
219 HAGGERTY LANE
QUADRANGLE MAP
BOZEMAN, MONTANA
2
N
FIGURECivil Engineering
Geotechnical EngineeringLand Surveying
32 DISCOVERY DRIVE . BOZEMAN, MT 59718PHONE (406) 582-0221 . FAX (406) 582-5770www.alliedengineering.com
219 HAGGERTY LANE
TEST PIT & BOREHOLE LOCATION MAP
BOZEMAN, MONTANA
3
BH-2
BH-1
N
LEGEND
TP-1
MW-1
FIGURECivil Engineering
Geotechnical EngineeringLand Surveying
32 DISCOVERY DRIVE . BOZEMAN, MT 59718PHONE (406) 582-0221 . FAX (406) 582-5770www.alliedengineering.com
219 HAGGERTY LANE
GEOLOGY MAP
BOZEMAN, MONTANA
4
N
LEGEND
FIGURECivil Engineering
Geotechnical EngineeringLand Surveying
32 DISCOVERY DRIVE . BOZEMAN, MT 59718PHONE (406) 582-0221 . FAX (406) 582-5770www.alliedengineering.com
219 HAGGERTY LANE
GROUNDWATER MAP
BOZEMAN, MONTANA
5
N
3.0' MIN4.0' MINNATIVE SUBGRADE3.0' MIN6" MIN6" MIN12" SPACING BETWEEN LAYERS OF GEOGRIDCivil EngineeringGeotechnical EngineeringLand Surveying32 DISCOVERY DRIVEBOZEMAN, MT 59718PHONE (406) 582-0221FAX (406) 582-5770www.alliedengineering.com219 HAGGERTY LANEFOUNDATION DETAILBOZEMAN, MONTANAFIG. 6219 HAGGERTY LANENOT TO SCALE
LIST OF APPENDICES
AAppppeennddiixx AA –– BBoorreehhoollee aanndd TTeesstt PPiitt LLooggss
AAppppeennddiixx BB –– LLaabboorraattoorryy TTeessttiinngg RReessuullttss
AAppppeennddiixx CC –– LLiimmiittaattiioonnss ooff YYoouurr GGeeootteecchhnniiccaall RReeppoorrtt
APPENDIX A
BBoorreehhoollee aanndd TTeesstt PPiitt LLooggss
DEPTH (FT)GEOLOGYLOGDESCRIPTIONOF MATERIALS
SAMPLESN(UNCOR)BLOWS/FTMOISTURECONTENTOTHER FIELD ORSAMPLEINFORMATION
2.0
32 DISCOVERY DRIVE
BOZEMAN, MT 59718
FAX (406) 582-5770
PHONE (406) 582-0221 LOG OF BORING
PROJECT: 219 Haggerty Lane JOB #: 22-097 DATE: 06/27/22 PAGE: 1 OF 1
LOCATION: 45.67596, -111.01615 ELEVATION: N/A DEPTH: 31.0'GW: 11.0'
DRILL TYPE: Hollow Stem Auger FIELD ENGINEER: JGE/ZWL BORING: BH-1
DRILLER: Bridger with O'Keefe CASING/HAMMER/SAMPLER: 8"/4.25"/140#SSS
{0.0' - 2.0'}: TopsoilStiff; dark brown; clayey SILT with organicsand roots; moist.
{2.0' - 9.0'}: Sandy ClayStiff to hard; brown; sandy lean CLAY;moist.
·Traces of cream/gray present from 2.0'to 4.0'.
·Occasional 1"-minus sub-rounded rockfrom 7.0' to 9.0'.
{9.0' - 14.0'}: Clayey GravelMedium dense to dense; brown with tracesof red and yellow; clayey GRAVEL withsand; wet.
·Primarily 1.5"-minus sub-angular rockfragments.
·Groundwater encountered at 11.0'.
·Perched water table from approximately11.0' to 19.0'.
{14.0' - 19.0'}: Clayey SandStiff; brown; clayey SAND; wet.
·50/50 mix of sand and clay.
·Located within the perched water table.
{19.0' - 31.0'}: Sandy ClayVery stiff to hard; brown; sandy CLAY;moist.
·Below the perched water table.
S1-A @0.0'-2.0'18.1%GENERAL NOTES:1. Grinding at 9.0'.2. Groundwater encountered at11.0'.3. Perched water table fromapproximately 11.0' - 19.0'.4. Composite A taken from 0.0' -31.0'.
·SSS - 2.0'' O.D. Split SpoonSample
·The beginning and endingdepths of the individual soillayers are approximate.
End of Boring
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
20.0
22.0
24.0
26.0
28.0
30.0
32.0
S1-B @2.0'-4.0'21.0%
S1-C @4.0'-6.0'19.3%
Geotechnical EngineeringLand SurveyingCivil Engineering
S1-D @7.0'-9.0'17.1%
S1-E @9.0'-11.0'14.2%
S1-F @12.0'-14.0'16.3%
S1-G @14.0'-16.0'34.5%
S1-H @19.0'-21.0'25.9%
S1-I @24.0'-26.0'23.6%
S1-J @29.0'-31.0'26.8%
5/5/5(10)
4/6/9(15)
5/13/21(34)
7/6/11(17)
15/16/13(29)
15/19/16(35)
4/5/7(12)
7/12/15(27)
11/32/49(81)
9/14/19(33)
LAB TESTING RESULTS:
Atterberg Limits from 4.0' to 6.0'PL = 19.7, LL = 26.8, PI = 7.0Soil Classification = CL (Lean Clay)
Atterberg Limits from 7.0' to 9.0'PL = 17.1, LL = 34.6, PI = 17.5Soil Classification = CL (Lean Clay)
S2-B @2.0'-4.0'25.6%
S2-C @4.0'-6.0'8.9%
Geotechnical EngineeringLand SurveyingCivil Engineering
S2-D @7.0'-9.0'14.7%
S2-E @9.0'-11.0'16.0%
S2-F @12.0'-14.0'35.6%
S2-G @14.0'-16.0'25.8%
S2-H @19.0'-21.0'33.7%
S2-I @24.0'-26.0'40.5%
S2-J @29.0'-31.0'31.7%DEPTH (FT)GEOLOGYLOGDESCRIPTIONOF MATERIALS
SAMPLESN(UNCOR)BLOWS/FTMOISTURECONTENTOTHER FIELD ORSAMPLEINFORMATION
2.0
32 DISCOVERY DRIVE
BOZEMAN, MT 59718
FAX (406) 582-5770
PHONE (406) 582-0221 LOG OF BORING
PROJECT: 219 Haggerty Lane JOB #: 22-097 DATE: 06/28/22 PAGE: 1 OF 1
LOCATION: 45.67613, -111.01605 ELEVATION: N/A DEPTH: 31.0'GW: 10.3'
DRILL TYPE: Hollow Stem Auger FIELD ENGINEER: JGE BORING: BH-2
DRILLER: Bridger with O'Keefe CASING/HAMMER/SAMPLER: 8"/4.25"/140#SSS
{0.0' - 2.0'}: TopsoilMedium stiff; dark brown; clayey SILT withorganics and roots; moist.
{2.0' - 4.0'}: Sandy ClayStiff; brown; sandy CLAY; moist.
{4.0' - 12.0'}: Clayey GravelMedium dense to dense; brown with tracesof red and yellow; clayey GRAVEL withsand; moist to wet.
·Minor clay content from 4.0' to 6.0'.
·Very clayey from 6.0' to 12.0'.
·Primarily 1.5"-minus sub-angular rockfragments.
·Groundwater encountered at 10.3'.
·Perched water table from approximately10.3' to 12.0'.
{12.0' - 31.0'}: Sandy ClayStiff to hard; brown; sandy fat CLAY; moistto very moist.
·Below the perched water table.
S2-A @0.0'-2.0'20.0%General Notes:1. Grinding at 10.0'.2. Groundwater encountered at10.3'.3. Perched water table fromapproximately 10.3' - 12.0'.4. Composite B taken from 0.0' -31.0'.5. Shelby Tube taken from 14.0' -15.0'.
·SSS - 2.0'' O.D. Split SpoonSample
·The beginning and endingdepths of the individual soillayers are approximate.
End of Boring
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
20.0
22.0
24.0
26.0
28.0
30.0
32.0
3/3/5(8)
3/4/6(10)
17/22/10(32)
9/24/17(41)
12/8/6(14)
2/4/8(12)
5/9/13(22)
7/13/15(28)
6/11/15(26)
9/15/18(33)
LAB TESTING RESULTS:
Atterberg Limits from 12.0' to 14.0'PL = 25.4, LL = 50.9, PI = 25.5Soil Classification = CH (Fat Clay)
DEPTH (FT)
SAMPLES
% WATER
CONTENTDESCRIPTION OF MATERIALSCivil EngineeringGeotechnical EngineeringWater Resource EngineeringLand Surveying32 Discovery DriveBozeman, MT 59718Phone (406) 582-0221Fax (406) 582-5770www.alliedengineering.com424681053451108642LAB TESTING RESULTS:Atterberg Limits at 8.0'PL = 26.1, LL = 46.2, PI = 20.2Soil Classification = CL (Lean Clay)2Surface Elevation: ~4,823'Backhoe Type: CAT 305 E2 Mini Exc.Job Number: 22-097.01Total Depth: 9.0'Groundwater Depth: 5.0'Backhoe Operator: Nick (ND Sitework)Logged By: JGE (AESI)Project: 219 Haggerty LaneDate: December 16, 20253{0.0' - 0.5'}: Organic Topsoil:Soft; dark brown; organic sandy SILT/CLAYwith roots and occasional gravels; moist.·Roots to ±18".{0.5' - 2.5'}: Clay with Gravel (Fill?):Very stiff; dark brown; sandy CLAY withscattered sub-rounded 8"-minus cobbles; moist.·May be fill.·Material contains some organics.·Pocket Pen @ 1.0' = 2.25 to 2.75 tsf.{2.5' - 3.5'}: Sand:Loose; rusty brown with abundant rust-coloredmottling; clean medium-grain SAND; very moist.·Caves easily when prodded.{3.5' - 7.0'}: Clayey Sandy Gravel:Medium dense; brown; clayey sandy GRAVELwith abundant 8"-minus sub-rounded cobblesand scattered 18" boulders; very moist to wet.·Clayier with depth (first foot is fairly clean).·Wetter with depth.·GW encountered at 5.0'.·Significant seepage entering at 6.0'.·Perched water table from 5.0' to 7.0'.·Some caving in this layer.{7.0' - 9.0'}: Silty Sandy Clay:Stiff; brown; silty sandy CLAY; very moist.·Pocket Pen at 8.0' = 1.0 - 1.5 tsf.·GW is flowing on top of this layer (perchedwater table).12Horizontal Distance in FeetTest Pit Designation: TP-1 Location:Front of Lot;See Test Pit Location Map;45.67625, -111.01587S1-A@1.5'20.6%S1-B@3.0'12.9%S1-C@4.0'14.1%S1-D@8.0'31.3%Perched water table from 5.0' to 7.0'GENERAL NOTES:1. MW-1 installed to a depth of 9.0'.2. TP-1 was located on the low side ofthe lot (adjacent to Haggerty Lane).
APPENDIX B
LLaabboorraattoorryy TTeessttiinngg RReessuullttss
MOISTURE CONTENT DETERMINATION (ASTM D-2216)
Project: 219 Haggerty Lane
Project Number: 22-097Sample Identification: See Below
Soil Classification: Varies
Date Sampled: 6/27/2022 and 6/28/2022
Date Tested: 6/30/2022 and 7/5/2022
Tested By: JGE
Sample Identification:S1-A S1-B S1-C S1-D S1-E S1-F S1-G S1-H S1-I S1-J
Exploration Location:BH-1 BH-1 BH-1 BH-1 BH-1 BH-1 BH-1 BH-1 BH-1 BH-1
Sample Depth (ft):0.0 - 2.0 2.0 - 4.0 4.0 - 6.0 7.0 - 9.0 9.0 - 11.0 12.0 - 14.0 14.0 - 16.0 19.0 - 21.0 24.0 - 26.0 29.0 - 31.0
Container Number:EE U HH Y M P GG S Q AA
Weight of Container:48.87 51.12 48.27 50.87 50.61 49.25 48.25 50.45 50.91 49.00
Container + Wet Soil:200.77 181.70 146.32 141.12 134.16 111.42 103.03 190.15 175.82 163.37
Container + Dry Soil:177.52 159.00 130.48 127.92 123.77 102.69 88.97 161.38 152.00 139.17
Weight of Water:23.25 22.70 15.84 13.20 10.39 8.73 14.06 28.77 23.82 24.20
Weight of Dry Soil:128.65 107.88 82.21 77.05 73.16 53.44 40.72 110.93 101.09 90.17
Moisture Content:18.1%21.0%19.3%17.1%14.2%16.3%34.5%25.9%23.6%26.8%
Sample Identification:S2-A S2-B S2-C S2-D S2-E S2-F S2-G S2-H S2-I S2-J
Exploration Location:BH-2 BH-2 BH-2 BH-2 BH-2 BH-2 BH-2 BH-2 BH-2 BH-2
Sample Depth (ft):0.0 - 2.0 2.0 - 4.0 4.0 - 6.0 7.0 - 9.0 9.0 - 11.0 12.0 - 14.0 14.0 - 16.0 19.0 - 21.0 24.0 - 26.0 29.0 - 31.0
Container Number:B LL UU F NN E L OO H TT
Weight of Container:31.57 31.06 30.98 31.72 30.89 31.64 31.71 31.10 31.58 30.91
Container + Wet Soil:88.82 86.13 110.29 123.32 148.23 94.67 99.47 116.82 97.97 113.82
Container + Dry Soil:79.29 74.89 103.79 111.58 132.01 78.13 85.56 95.19 78.82 93.86
Weight of Water:9.53 11.24 6.50 11.74 16.22 16.54 13.91 21.63 19.15 19.96
Weight of Dry Soil:47.72 43.83 72.81 79.86 101.12 46.49 53.85 64.09 47.24 62.95
Moisture Content:20.0%25.6%8.9%14.7%16.0%35.6%25.8%33.7%40.5%31.7%
Reviewed By:
32 Discovery DriveBozeman, MT 59718
Phone (406) 582-0221
Fax (406) 582-5770
MOISTURE CONTENT DETERMINATION (ASTM D2216)Project: 219 Haggerty Lane Project Number: 22‐097.01Sample Identification: See BelowSoil Classification: Varies Date Sampled: 12/16/2025 Date Tested: 12/16/2025 Tested By: JGE Sample Identification: S1‐AS1‐BS1‐CS1‐D Exploration Location: TP‐1TP‐1TP‐1TP‐1 Sample Depth (ft):1.5 3.0 4.0 8.0 Container Number:R ZZ BB GG Weight of Container: 50.50 49.38 48.29 48.18 Container + Wet Soil: 299.17 339.70 352.70 267.47 Container + Dry Soil: 256.61 306.59 314.99 215.22 Weight of Water:42.56 33.11 37.71 52.25 Weight of Dry Soil: 206.11 257.21 266.70 167.04 Moisture Content: 20.6% 12.9% 14.1% 31.3% Sample Identification: Exploration Location: Sample Depth (ft): Container Number: Weight of Container: Container + Wet Soil: Container + Dry Soil: Weight of Water: Weight of Dry Soil: Moisture Content: Reviewed By:32 Discovery DriveBozeman, MT 59718Phone (406) 582‐0221Fax (406) 582‐5770
ATTERBERG LIMITS DETERMINATION (ASTM D-4318)
Project: 219 Haggerty LaneProject Number: 22-097Sample Identification: S1-C from 4.0' - 6.0'
Soil Classification: Lean CLAY (CL)
Date Sampled: June 27, 2022
Date Tested: July 6, 2022Tested By: Zach Liley
Test Results
Plastic Limit:19.7
Liquid Limit:26.8
Plasticity Index:7.0
Reviewed By:_________________
A-Line
CL
ML or OL
CH
MH or OH
CL-ML
ML
0
10
20
30
40
50
60
0 10 20 30 40 50 60 70 80 90 100Plasticity IndexLiquid Limit
PLASTICITY CHART
32 Discovery Drive
Bozeman, MT 59718
Phone (406) 582-0221
Fax (406) 582-5770
ATTERBERG LIMITS DETERMINATION (ASTM D-4318)
Project: 219 Haggerty LaneProject Number: 22-097Sample Identification: S1-D from 7.0' - 9.0'
Soil Classification: Lean CLAY (CL)
Date Sampled: June 27, 2022
Date Tested: July 6, 2022Tested By: Zach Liley
Test Results
Plastic Limit:17.1
Liquid Limit:34.6
Plasticity Index:17.5
Reviewed By:_________________
A-Line
CL
ML or OL
CH
MH or OH
CL-ML
ML
0
10
20
30
40
50
60
0 10 20 30 40 50 60 70 80 90 100Plasticity IndexLiquid Limit
PLASTICITY CHART
32 Discovery Drive
Bozeman, MT 59718
Phone (406) 582-0221
Fax (406) 582-5770
ATTERBERG LIMITS DETERMINATION (ASTM D-4318)
Project: 219 Haggerty LaneProject Number: 22-097Sample Identification: S2-F from 12.0' - 14.0'
Soil Classification: Fat CLAY (CH)
Date Sampled: June 28, 2022
Date Tested: July 6, 2022Tested By: Zach Liley
Test Results
Plastic Limit:25.4
Liquid Limit:50.9
Plasticity Index:25.5
Reviewed By:_________________
A-Line
CL
ML or OL
CH
MH or OH
CL-ML
ML
0
10
20
30
40
50
60
0 10 20 30 40 50 60 70 80 90 100Plasticity IndexLiquid Limit
PLASTICITY CHART
32 Discovery Drive
Bozeman, MT 59718
Phone (406) 582-0221
Fax (406) 582-5770
ATTERBERG LIMITS DETERMINATION (ASTM D4318)
Project: 219 Haggerty Lane Project Number: 22-097.01 Sample Identification: S1-D at 8.0'
Soil Classification: Lean Clay (CL)
Date Sampled: 12/16/2025
Date Tested: 1/14/2026Tested By: JSH
Test Results
Plastic Limit:26.1
Liquid Limit:46.2
Plasticity Index:20.2
Reviewed By:_________________
A-Line
CL
ML or OL
CH
MH or OH
CL-ML
ML
0
10
20
30
40
50
60
0 10 20 30 40 50 60 70 80 90 100Plasticity IndexLiquid Limit
PLASTICITY CHART
32 Discovery Drive
Bozeman, MT 59718
Phone (406) 582-0221
Fax (406) 582-5770
APPENDIX C
LLiimmiittaattiioonnss ooff YYoouurr GGeeootteecchhnniiccaall RReeppoorrtt
LIMITATIONS OF YOUR GEOTECHNICAL REPORT
GEOTECHNICAL REPORTS ARE PROJECT AND CLIENT SPECIFIC
Geotechnical investigations, analyses, and recommendations are project and client specific. Each project
and each client have individual criterion for risk, purpose, and cost of evaluation that are considered in
the development of scope of geotechnical investigations, analyses and recommendations. For example,
slight changes to building types or use may alter the applicability of a particular foundation type, as can a
particular client’s aversion or acceptance of risk. Also, additional risk is often created by scope‐of service
limitations imposed by the client and a report prepared for a particular client (say a construction
contractor) may not be applicable or adequate for another client (say an architect, owner, or developer
for example), and vice‐versa. No one should apply a geotechnical report for any purpose other than that
originally contemplated without first conferring with the consulting geotechnical engineer. Geotechnical
reports should be made available to contractors and professionals for information on factual data only
and not as a warranty of subsurface conditions, such as those interpreted in the exploration logs and
discussed in the report.
GEOTECHNICAL CONDITIONS CAN CHANGE
Geotechnical conditions may be affected as a result of natural processes or human activity. Geotechnical
reports are based on conditions that existed at the time of subsurface exploration. Construction
operations such as cuts, fills, or drains in the vicinity of the site and natural events such as floods,
earthquakes, or groundwater fluctuations may affect subsurface conditions and, thus, the continuing
adequacy of a geotechnical report.
GEOTECHNICAL ENGINEERING IS NOT AN EXACT SCIENCE
The site exploration and sampling process interprets subsurface conditions using drill action, soil sampling,
resistance to excavation, and other subjective observations at discrete points on the surface and in the
subsurface. The data is then interpreted by the engineer, who applies professional judgment to render
an opinion about over‐all subsurface conditions. Actual conditions in areas not sampled or observed may
differ from those predicted in your report. Retaining your consultant to advise you during the design
process, review plans and specifications, and then to observe subsurface construction operations can
minimize the risks associated with the uncertainties associated with such interpretations. The conclusions
described in your geotechnical report are preliminary because they must be based on the assumption that
conditions revealed through selective exploration and sampling are indicative of actual
Allied Engineering Services, Inc. ● 32 Discovery Drive. Bozeman, Montana 59718 ● Ph: (406) 582‐0221 Page 2
Final explorations logs developed by the consultant are based upon interpretation of field logs (assembled
by site personnel), field test results, and laboratory and/or office evaluation of field samples and data.
Only final exploration logs and data are customarily included in geotechnical reports. These final logs
should not be redrawn for inclusion in Architectural or other design drawings, because drafters may
commit errors or omissions in the transfer process.
To reduce the likelihood of exploration log misinterpretation, contractors should be given ready access to
the complete geotechnical report and should be advised of its limitations and purpose. While a contractor
may gain important knowledge from a report prepared for another party, the contractor should discuss
the report with Allied Engineering and perform the additional or alternative work believed necessary to
obtain the data specifically appropriate for construction cost estimating purposes.
OWNERSHIP OF RISK AND STANDARD OF CARE
Because geotechnical engineering is much less exact than other design disciplines, there is more risk
associated with geotechnical parameters than with most other design issues. Given the hidden and
variable character of natural soils and geologic hazards, this risk is impossible to eliminate with any
amount of study and exploration. Appropriate geotechnical exploration, analysis, and recommendations
can identify and reduce these risks. However, assuming an appropriate geotechnical evaluation, the
remaining risk of unknown soil conditions and other geo‐hazards typically belongs to the owner of a
project unless specifically transferred to another party such as a contractor, insurance company, or
engineer. The geotechnical engineer’s duty is to provide professional services in accordance with their
stated scope and consistent with the standard of practice at the present time and in the subject geographic
area. It is not to provide insurance against geo‐hazards or unanticipated soil conditions.
The conclusions and recommendations expressed in this report are opinions based our professional
judgment and the project parameters as relayed by the client. The conclusions and recommendations
assume that site conditions are not substantially different than those exposed by the explorations. If
during construction, subsurface conditions different from those encountered in the explorations are
observed or appear to be present, Allied Engineering should be advised at once such that we may review
those conditions and reconsider our recommendations where necessary.
RETENTION OF SOIL SAMPLES
Allied Engineering will typically retain soil samples for one month after issuing the geotechnical report. If
you would like to hold the samples for a longer period of time, you should make specific arrangements to
have the samples held longer or arrange to take charge of the samples yourself.
conditions throughout a site. A more complete view of subsurface conditions is often revealed during
earthwork; therefore, you should retain your consultant to observe earthwork to confirm conditions
and/or to provide revised recommendations if necessary. Allied Engineering cannot assume responsibility
or liability for the adequacy of the report’s recommendations if another party is retained to observe
construction.
EXPLORATIONS LOGS SHOULD NOT BE SEPARATED FROM THE REPORT