Loading...
HomeMy WebLinkAboutDrainage Report V1 (2)�E IDIAN> APPROVED DATE 03/02/22 FILE NUMBER: Fa-2021-oo51 THE LAND GROUP Seasons at Meridian 2700 E. Overland Road Meridian, ID 83642 Storm Water Management & Engineered Drainage Report Engineer The Land Group, Inc. 462 Eaglealdaho 83616 Drive, Ste. 100 el? NAL G\ST st Shore Ph:208.939.4041 0 , Prepared By: Riley Langan, El s09/28/20210 Reviewed By: James W. Gute, PE �qT f o f 0 J September 281h, 2021 9 W'G TLG Project No. 120124 462 East Shore Drive, Suite 100, Eagle, Idaho 83616 208.939.4041 thelandgroupinc.com CUEIDR IAy Seasons at Meridian 2700 E. Overland Road, Meridian, ID 83642 Storm Water Management & Engineered Drainage Report APPROVED DATE 03/02/22 FILE NUMBER: FP- 21- 11 Description The proposed construction is a multi -family apartment complex on a 15.875-Acre parcel located at 2700 E. Overland Road in Meridian, ID. The site consists of 10 multi-plex units, a clubhouse, maintenance room and complex pool area. Landscaping, paved drive isles and parking areas will be constructed throughout the site. All stormwater runoff will be infiltrated and treated on -site by seepage beds. Existing Condition Currently, the site is undeveloped and consists of cultivated farmland. Stormwater falling on the undeveloped area infiltrates in place. The general topography of the site is gradually sloping from northeast to southwest. All geotechnical considerations were investigated by Atlas Technical Consultants and detailed in the Geotechnical Report dated October 19th, 2020 (File No. 13201400g). Referenced report is attached in Appendix C. For construction purposes, groundwater depth is estimated to remain greater than 15 feet below ground surface throughout the year. On -Site Proposed Condition The proposed site development includes 14 tributary drainage areas shown in Appendix A. Generally, collection, routing, and treatment of storm drainage from the project is as follows: 1. Roadways and parking areas sheet flow to catch -curbs where they are conveyed to curb inlets. 2. Rooftop gutters collect and convey drainage to a seepage bed. 3. Stormwater landing on landscaping areas shall infiltrate in place. 4. Drainage flows through the catch basins/gutters into a storm drain piping network, and sand & grease traps prior to being conveyed into seepage beds for final disposal via infiltration to the native soils underlying the project site. ACHD Proposed Condition The proposed right-of-way development includes 3 tributary drainage areas shown in Appendix A. Generally, collection, routing and treatment of storm drainage from the project is as follows: 1. Roadways slope to catch -curbs where they are conveyed to curb inlets. 2. Drainage flows through the catch basins into a storm drain piping network, and sand & grease traps prior to being conveyed into seepage beds for final disposal via infiltration to the native soils underlying the project site. Peak Rate of Discharge and Storage Volume Peak storm discharge and required storage volume was determined using the Rational Method, with a 100-year storm return period. An infiltration rate of 8 inches per hour was used to determine the percolation rate. Poorly graded gravel with sand sediments were experienced throughout the site and typically provide free -drainage into native subsoils. Drainage calculations are attached in Appendix B. THE LAND 462 East Shore Drive, Suite 100, Eagle, Idaho 83616 208.939.4041 thelandgroupinc.com LE GROUP Seasons at Meridian 2700 E. Overland Road, Meridian, ID 83642 Storm Water Management & Engineered Drainage Report APPROVED DA EI 03/02/22 endix A Drainage Basin Map THE LAND GROUP APPROVED Chi OMM2 FU MMBFA:-a \ 1 l \ 1 I/ I R/ ` VfiV R/W R/W\ AREA A 14,002 sf 0.321 ac i AREA B \ 24,581 sf 0.564 ac Exhibit -Storm Drainage Watershed Map Horizontal Scale: 1" = 150' 0 150, 300' ONSITE SUB -BASIN LEGEND: PO3MOLl9 MFA=],891-SF MffRJX]USMFA= M,77 F Mev El ffRNWSOPFA=4,596SF I MPEOMOUS MEA=11,fi9S�F PEfIOX]IISMFA=2q 47 IMffNMW5 MIFA= N,d]55F MG9 PEOMOLlS An. SE 27, = IMPEPMOUSMFA 1].1549 ERVIWS01✓FA=12,1965F IMff6M0U5 MFA=24,3185F MA10 Pp1M01k MFA = 7.BI6-SF IMPFRNOOS An. -50.1605E -d ffflMWSOPFA=12,d91-SF IMffflM0U5 MEA =38,fi3]-SF M.FA11 OUS A =15.9. IFNERJNMIO MFA=50.2905F IMPAfi Ke MEA= 8,1425E IMPEIrv10U3MFA=35,]91hY IMff 12 MFA = EOMOUS8.9- INMIISMFA = d],6105f MPAfi ffflMOLIS MFA =2,4305F IMPEPMOUSMEA =10,943 4965E INMOUS MFA 35.I52-SF MA] PEflM0U5 MFA =6,5865F IMff flMOLIS MFA =10.1309 FENVMIISMFA=12,p905F IMff RM0U0 MFA = 24,O66SF ACHD SUB -BASIN LEGEND: = I-F PEIMpIS01EA= 3.5]45F I-0111SARB 12,37e5F IMffRM0U5 MFA=21,0005F 11MOO5 MFA=-22. F MffRVUS - = 22,2665E 0 =THE LAND GROUP _ W Z O H y aa�ts Ca Z W Z W Cc= CM CA CC Z Z A Z Cn Cs L o0 Cyr �m Revisions 1. Project 1 120124 Date of Issuance: 09/28/2021 Storm Drainage Watershed Map if 1 �I Seasons at Meridian 2700 E. Overland Road, Meridian, ID 83642 Storm Water Management & Engineered Drainage Report APPROVED DA EI 03/02/22 endix B Storm Drainage Calculations THE LAND GROUP �E IDIAN-- APPROVED DATE 03/02/22 FIEF NUMBER PP-�...-oos. e rv"" i at Meridian - Area 1 us Area = Area = FArea = FArea = C Coefficient = Drainage System Characteristics System Infiltration Rate = Swale Top Area = Swale Bottom Area = Swale Depth = Swale Volume = Inf Trench Width = Inf Trench Length = Inf Trench Depth = Storage Volume of trench = Total Volume = Infiltration Area = Infiltration Rate = 38,772 sf 7,694 sf 46,466 sf 1.07 acres 0.83 8.00 in./hr - sf - sf 0.00 ft - cf 7.00 ft 125.00 ft 9.00 ft 3150 cf 3,150 cf 875 sf 583 cf/hr Drainage Calculations Basin Developed Volume Prepared By: Riley Langan Date:09/28/2021 Project #: 120124 Storage Volume Required (100-yr Storm) (based on Zone "A" IDF Curve, 100-yr Return Period) Intensity Time (min) Time (sec):1 (in/hr) Q dev. (cfs) V dev. (cf) V inf. (cf) Vs (cf) 10 ........................................................................... 600 3.11 2.74 ..................................................................................................................................................................................................................................................... 1,644 97 1,547 15 900 2.62 2.31 2,077 146 1,931 20 1,200 2.28 2.01 2,410 194 2,216 30 1,800 1.82 1.60 ................................................................................................................................................................................................................................ 2,886 292 2,594 40 .................................................................................................... 2,400 1.37 1.21 ..................................................................................................................................................................................................................................................... 2,896 389 2,508 50 .......................................................................................................... 3,000 1.17 1.03 .................................................................................................................................................................................................' 3,092 486 2,606 60 .......................................................................................................... 3,600 1.15 1.01 ................................................................................................................................................................................................. 3,647 583 120 .......................................................................................................... 7,200 0.66 0.58 ..................................................................................................................................................................................................................................................... 4,186 1,167 3,019 180 .......................................................................................................... .10,800 0.48 0.42 ..................................................................................................................................................................................................................................................... 4,567 1,750 2,817 360 ........................................................................................................... 21,600 0.30 0.26 ......................................................................................................................,.....................................................................e.................................................... 5,708 3,500 2,208 720 43,200 1 0. 9 0.17 ............................................................................................................................................................................................... 7,230 7,000 230 1...440 86 400 0.12 0.11 9,133 14,000 -4,867 System Checks Maximum Runoff Developed = 3,064 cf Total Volume Provided = 3,150 cf System OK (Excess Capacity) System Recovery Maximum Runoff = 3,064 cf Other Sources = 0 cf Percolation Volume = 3,064 cf Recovery Time = 5.3 hours System Summary: 7.00 ft wide x 9.00 ft deep x 125.00 ft long Sand & Grease Trap: 1500-Gal 1000-Gal Trap Size 1000-Gal 7.08 sf Maximum Discharge = 2.74 cfs System OK (Excess Capacity) Velocity = 0.39 fps Number of Traps (in parallel) = 1 CD Seasons at Meridian SeepageBedSizing 120124.xlsx �E IDIAN-- APPROVED DATE 03/02/22 FIEF NUMBER PP-�...-oos. e rv"" i at Meridian - Area 2 us Area = Area = FArea = FArea = C Coefficient = Drainage System Characteristics System Infiltration Rate = Swale Top Area = Swale Bottom Area = Swale Depth = Swale Volume = Inf Trench Width = Inf Trench Length = Inf Trench Depth = Storage Volume of trench = Total Volume = Infiltration Area = Infiltration Rate = 70,475 sf 20,072 sf 90,547 sf 2.08 acres 0.78 8.00 in./hr - sf - sf 0.00 ft - cf 24.00 ft 76.00 ft 8.00 ft 5837 cf 5,837 cf 1,824 sf 1,216 cf/hr Drainage Calculations Basin Developed Volume Prepared By: Riley Langan Date:09/28/2021 Project #: 120124 Storage Volume Required (100-yr Storm) (based on Zone "A" IDF Curve, 100-yr Return Period) Intensity Time (min) Time (sec):1 (in/hr) Q dev. (cfs) V dev. (cf) V inf. (cf) Vs (cf) 10 ........................................................................... 600 3.11 5.07 ..................................................................................................................................................................................................................................................... 3,040 203 2,837 15 900 2.62 4.27 3,842 304 3,538 20 1,200 2.28 3.71 4,457 405 4,052 30 1,800 1.82 2.97 ................................................................................................................................................................................................................................ 5,337 608 4,729 40 .................................................................................................... 2,400 1.37 2.23 ..................................................................................................................................................................................................................................................... 5,357 811 4,546 50 .......................................................................................................... 3,000 1.17 1.91 .................................................................................................................................................................................................' 5,718 1,013 4,705 60 .......................................................................................................... 3,600 1.15 1.87 ................................................................................................................................................................................................. 6,745 1,216 120 .......................................................................................................... 7,200 0.66 1.08 ..................................................................................................................................................................................................................................................... 7,742 2,432 5,310 180 .......................................................................................................... .10,800 0.48 0.78 ..................................................................................................................................................................................................................................................... 8,445 3,648 4,797 360 ........................................................................................................... 21,600 0.30 0.49 ............................................................................................................................,.....................................................................e.................................................... 10,557 7,296 3,261 720 43,200 1 0. 9 0.31 ............................................................................................................................................................................................... 13,372 14,592 -1,220 1...440 86 400 0.12 0.20 16,891 29,184 -12,293 System Checks Maximum Runoff Developed = 5,529 cf Total Volume Provided = 5,837 cf System OK (Excess Capacity) System Recovery Maximum Runoff = 5,529 cf Other Sources = 0 cf Percolation Volume = 5,529 cf Recovery Time = 4.5 hours System Summary: 24.00 ft wide x 8.00 ft deep x 76.00 ft long Sand & Grease Trap: 1500-Gal 1000-Gal Trap Size 1000-Gal 7.08 sf Maximum Discharge = 5.07 cfs Not OK (Insufficient Capacity) Velocity = 0.72 fps Number of Traps (in parallel) = 1 CD Seasons at Meridian SeepageBedSizing 120124.xlsx �E IDIAN-- APPROVED DATE 03/02/22 FIEF NUMBER PP-�...-oos. e rv"" ; at Meridian - Area 3 us Area = Area = FArea = FArea = C Coefficient = Drainage System Characteristics System Infiltration Rate = Swale Top Area = Swale Bottom Area = Swale Depth = Swale Volume = Inf Trench Width = Inf Trench Length = Inf Trench Depth = Storage Volume of trench = Total Volume = Infiltration Area = Infiltration Rate = 24,318 sf 12,190 sf 36,508 sf 0.84 acres 0.70 8.00 in./hr - sf - sf 0.00 ft - cf 10.00 ft 70.00 ft 8.00 ft 2240 cf 2,240 cf 700 sf 467 cf/hr Drainage Calculations Basin Developed Volume Prepared By: Riley Langan Date:09/28/2021 Project #: 120124 Storage Volume Required (100-yr Storm) (based on Zone "A" IDF Curve, 100-yr Return Period) Intensity Time (min) Time (sec):1 (in/hr) Q dev. (cfs) V dev. (cf) V inf. (cf) Vs (cf) 10 ..................................................................... 600 3.11 1.82 ..................................................................................................................................................................................................................................................... 1,094 78 1,016 15 900 2.62 1.54 1,383 117 1,266 20 1,200 2.28 1.34 1,604 156 1,449 30 1,800 1.82 1.07 ................................................................................................................................................................................................................................ 1,921 233 1,687 40 ...................................................................... 2,400 1.37 0.80 ..................................................................................................................................................................................................................................................... 1,928 311 1,617 50 ...................................................................... 3,000 1.17 0.69 .................................................................................................................................................................................................' 2,058 389 1,669 60 ...................................................................... 3,600 1.15 0.67 ................................................................................................................................................................................................. 2,427 467 120 ...................................................................... 7,200 0.66 0.39 ..................................................................................................................................................................................................................................................... 2,786 933 1,853 180 ...................................................................... ,10,800 0.48 0.28 ..................................................................................................................................................................................................................................................... 3,039 1,400 1,639 .................................... 360 ................................... 21,600 0.30 0.18 ......................................................................................................................,.....................................................................e.................................................... 3,799 2,800 999 720 43,200 1 0. 9 0.11 ............................................................................................................................................................................................... 4,813 5,600 -787 1 440 86 400 0.12 0.07 6,079 11,200 -5,121 System Checks Maximum Runoff Developed = 1,961 cf Other Sources = cf Total Volume Provided = 2,240 cf System OK (Excess Capacity) System Recovery Maximum Runoff = 1,961 cf Other Sources = 0 cf Percolation Volume = 1,961 cf Recovery Time = 4.2 hours System Summary: 10.00 ft wide x 8.00 ft deep x 70.00 ft long Sand & Grease Trap: 1500-Gal 1000-Gal Trap Size 1500-Gal 9.71 sf Maximum Discharge = 1.82 cfs System OK (Excess Capacity) Velocity = 0.19 fps Number of Traps (in parallel) = 1 CD Seasons at Meridian SeepageBedSizing 120124.xlsx �E IDIAN-- APPROVED DATE 03/02/22 FIEF NUMBER PP-�...-oos. e rv"" at Meridian - Area 4 us Area = Area = FArea = FArea = C Coefficient = Drainage System Characteristics System Infiltration Rate = Swale Top Area = Swale Bottom Area = Swale Depth = Swale Volume = Inf Trench Width = Inf Trench Length = Inf Trench Depth = Storage Volume of trench = Total Volume = Infiltration Area = Infiltration Rate = 38,637 sf 12,491 sf 51,128 sf 1.17 acres 0.77 8.00 in./hr - sf - sf 0.00 ft - cf 10.00 ft 100.00 ft 8.00 ft 3200 cf 3,200 cf 1,000 sf 667 cf/hr Drainage Calculations Basin Developed Volume Prepared By: Riley Langan Date:09/28/2021 Project #: 120124 Storage Volume Required (100-yr Storm) (based on Zone "A" IDF Curve, 100-yr Return Period) Intensity Time (min) Time (sec):1 (in/hr) Q dev. (cfs) V dev. (cf) V inf. (cf) Vs (cf) 10 ........................................................................... 600 3.11 2.80 ..................................................................................................................................................................................................................................................... 1,679 111 1,568 15 900 2.62 2.36 2,122 167 1,955 20 1,200 2.28 2.05 2,462 222 2,240 30 1,800 1.82 1.64 ................................................................................................................................................................................................................................ 2,948 333 2,615 40 .................................................................................................... 2,400 1.37 1.23 ..................................................................................................................................................................................................................................................... 2,959 444 2,515 50 3,000 1.17 1.05 3,159 ................i.....................................................................' 556 2,603 60 .......................................................................................................... 3,600 1.15 1.03 ................................................................................................................................................................................................. 3,726 667 120 .......................................................................................................... 7,200 0.66 0.59 ..................................................................................................................................................................................................................................................... 4,277 1,333 2,943 180 .......................................................................................................... .10,800 0.48 0.43 ..................................................................................................................................................................................................................................................... 4,666 2,000 2,666 360 ........................................................................................................... 21,600 0.30 0.27 ......................................................................................................................,.....................................................................e.................................................... 5,832 4,000 1,832 720 43,200 1 0. 9 0.17 ............................................................................................................................................................................................... 7,387 8,000 -613 1...440 86 400 0.12 0.11 9,331 16,000 -6,669 System Checks Maximum Runoff Developed = 3,059 cf Total Volume Provided = 3,200 cf System OK (Excess Capacity) System Recovery Maximum Runoff = 3,059 cf Other Sources = 0 cf Percolation Volume = 3,059 cf Recovery Time = 4.6 hours System Summary: 10.00 ft wide x 8.00 ft deep x 100.00 ft long Sand & Grease Trap: 1500-Gal 1000-Gal Trap Size 1000-Gal 7.08 sf Maximum Discharge = 2.80 cfs System OK (Excess Capacity) Velocity = 0.40 fps Number of Traps (in parallel) = 1 CD Seasons at Meridian SeepageBedSizing 120124.xlsx �E IDIAN-- APPROVED DATE 03/02/22 FIEF NUMBER PP-�...-oos. e rv"" at Meridian - Area 5 us Area = Area = FArea = FArea = C Coefficient = Drainage System Characteristics System Infiltration Rate = Swale Top Area = Swale Bottom Area = Swale Depth = Swale Volume = Inf Trench Width = Inf Trench Length = Inf Trench Depth = Storage Volume of trench = Total Volume = Infiltration Area = Infiltration Rate = 35,790 sf 8,142 sf 43,932 sf 1.01 acres 0.81 8.00 in./hr - sf - sf 0.00 ft - cf 10.00 ft 110.00 ft 7.00 ft 3080 cf 3,080 cf 1,100 sf 733 cf/hr Drainage Calculations Basin Developed Volume Prepared By: Riley Langan Date:09/28/2021 Project #: 120124 Storage Volume Required (100-yr Storm) (based on Zone "A" IDF Curve, 100-yr Return Period) Intensity Time (min) Time (sec):1 (in/hr) Q dev. (cfs) V dev. (cf) V inf. (cf) Vs (cf) 10 ........................................................................... 600 3.11 2.54 ..................................................................................................................................................................................................................................................... 1,526 122 1,404 15 900 2.62 2.14 1,929 183 1,745 20 1,200 2.28 1.86 2,238 244 1,993 30 1,800 1.82 1.49 ............................................................................................................................................................................................................................... 2,680 367 2,313 40 .................................................................................................... 2,400 1.37 1.12 .................................................................................................................................................................................................................................................... 2,689 489 2,200 50 .......................................................................................................... 3,000 1.17 0.96 ................................................................................................................................................................................................' 2,871 611 2,260 60 3,600 1.15 0.94 .......................................................................................................................................... 3,386 733 120 .......................................................................................................... 7,200 0.66 0.54 .................................................................................................................................................................................................................................................... 3,887 1,467 2,420 180 10,800 0.48 0.39 .............................................................................................................................................................................................. 4,240 2,200 2,040 360 ........................................................................................................... 21,600 0.30 0.25 ...........................................................................................................................................................................................e.................................................... 5,300 4,400 900 720 43,200 1 0. 9 0.16 ............................................................................................................................................................................................... 6,714 8,800 -2,086 1...440 86 400 0.12 0.10 8,480 17,600 -9,120 System Checks Maximum Runoff Developed = 2,653 cf Total Volume Provided = 3,080 cf System OK (Excess Capacity) System Recovery Maximum Runoff = 2,653 cf Other Sources = 0 cf Percolation Volume = 2,653 cf Recovery Time = 3.6 hours System Summary: 10.00 ft wide x 7.00 ft deep x 110.00 ft long Sand & Grease Trap: 1500-Gal 1000-Gal Trap Size 1000-Gal 7.08 sf Maximum Discharge = 2.54 cfs System OK (Excess Capacity) Velocity = 0.18 fps Number of Traps (in series) = 2 CD Seasons at Meridian SeepageBedSizing 120124.xlsx �E IDIAN-- APPROVED DATE 03/02/22 FIEF NUMBER PP-�...-oos. e rv"" at Meridian - Area 6 us Area = Area = FArea = FArea = C Coefficient = Drainage System Characteristics System Infiltration Rate = Swale Top Area = Swale Bottom Area = Swale Depth = Swale Volume = Inf Trench Width = Inf Trench Length = Inf Trench Depth = Storage Volume of trench = Total Volume = Infiltration Area = Infiltration Rate = 18,274 sf 2,438 sf 20,712 sf 0.48 acres 0.86 8.00 in./hr - sf - sf 0.00 ft - cf 10.00 ft 50.00 ft 7.00 ft 1400 cf 1,400 cf 500 sf 333 cf/hr Drainage Calculations Basin Developed Volume Prepared By: Riley Langan Date:09/28/2021 Project #: 120124 Storage Volume Required (100-yr Storm) (based on Zone "A" IDF Curve, 100-yr Return Period) Intensity Time (min) Time (sec):1 (in/hr) Q dev. (cfs) V dev. (cf) V inf. (cf) Vs (cf) 10 600 3.11 1.27 765 56 709 15 900 2.62 1.07 966 83 883 20 1,200 2.28 0.93 1,121 111 1,010 30 1,800 1.82 0.75 ................................................................................................................................................................................................................................ 1,342 167 1,176 40 .................................................................................................... 2,400 1.37 0.56 ..................................................................................................................................................................................................................................................... 1,347 222 1,125 50 .......................................................................................................... 3,000 1.17 0.48 .................................................................................................................................................................................................' 1,438 278 1,160 60 3,600 1.15 0.47 .......................................................................................................................................... 1,696 333 120 7,200 0.66 0.27 1,947 667 1,280 180 ......................................................................................................................... 10,800 0.48 0.20 .................................................................................................................................................................................................................................................... 2,124 1,000 1,124 360 ......................................................720 ......... 21,600 0.30 0.12 ............................................................................................................................,.....................................................................e.................................................... 2,655 2,000 655 :. 43 200 0.19 0.08 ................................................................................................................................................................................................ 3,363 4,000 -637 1...440 86 400 0.12 0.05 4,248 8,000 -3,752 System Checks Maximum Runoff Developed = 1,363 cf Total Volume Provided = 1,400 cf System OK (Excess Capacity) System Recovery Maximum Runoff = 1,363 cf Other Sources = 0 cf Percolation Volume = 1,363 cf Recovery Time = 4.1 hours System Summary: 10.00 ft wide x 7.00 ft deep x 50.00 ft long Sand & Grease Trap: 1500-Gal 1000-Gal Trap Size 1000-Gal 7.08 sf Maximum Discharge = 1.27 cfs System OK (Excess Capacity) Velocity = 0.18 fps Number of Traps (in parallel) = 1 CD Seasons at Meridian SeepageBedSizing 120124.xlsx �E IDIAN-- APPROVED DATE 03/02/22 FIEF NUMBER PP-�...-oos. e rv"" at Meridian - Area 7 us Area = Area = FArea = FArea = C Coefficient = Drainage System Characteristics System Infiltration Rate = Swale Top Area = Swale Bottom Area = Swale Depth = Swale Volume = Inf Trench Width = Inf Trench Length = Inf Trench Depth = Storage Volume of trench = Total Volume = Infiltration Area = Infiltration Rate = 48,130 sf 6,585 sf 54,715 sf 1.26 acres 0.86 8.00 in./hr - sf - sf 0.00 ft - cf 11.00 ft 100.00 ft 9.00 ft 3960 cf 3,960 cf 1,100 sf 733 cf/hr Drainage Calculations Basin Developed Volume Prepared By: Riley Langan Date:09/28/2021 Project #: 120124 Storage Volume Required (100-yr Storm) (based on Zone "A" IDF Curve, 100-yr Return Period) Intensity Time (min) Time (sec):1 (in/hr) Q dev. (cfs) V dev. (cf) V inf. (cf) Vs (cf) 10 ........................................................................... 600 3.11 3.36 ..................................................................................................................................................................................................................................................... 2,015 122 1,893 15 900 2.62 2.83 2,546 183 2,363 20 1,200 2.28 2.46 2,955 244 2,710 30 1,800 1.82 1.97 ................................................................................................................................................................................................................................ 3,538 367 3,171 40 .................................................................................................... 2,400 1.37 1.48 ..................................................................................................................................................................................................................................................... 3,551 489 3,062 50 .......................................................................................................... 3,000 1.17 1.26 .................................................................................................................................................................................................' 3,790 611 3,179 60 .......................................................................................................... 3,600 1.15 1.24 ................................................................................................................................................................................................. 4,471 733 120 .......................................................................................................... 7,200 0.66 0.71 ..................................................................................................................................................................................................................................................... 5,132 1,467 3,665 180 .......................................................................................................... .10,800 0.48 0.52 ..................................................................................................................................................................................................................................................... 5,598 2,200 3,398 360 ........................................................................................................... 21,600 0.30 0.32 ........................................................................................................................,.....................................................................e.................................................... 6,998 4,400 2,598 720 43,200 1 0. 9 0.21 :............................................................................................................................................................................................... 8,864 8,800 64 1...440 86 400 0.12 0.13 11,196 17,600 -6,404 System Checks Maximum Runoff Developed = 3,737 cf Total Volume Provided = 3,960 cf System OK (Excess Capacity) System Recovery Maximum Runoff = 3,737 cf Other Sources = 0 cf Percolation Volume = 3,737 cf Recovery Time = 5.1 hours System Summary: 11.00 ft wide x 9.00 ft deep x 100.00 ft long Sand & Grease Trap: 1500-Gal 1000-Gal Trap Size 1000-Gal 7.08 sf Maximum Discharge = 3.36 cfs System OK (Excess Capacity) Velocity = 0.47 fps Number of Traps (in parallel) = 1 CD Seasons at Meridian SeepageBedSizing 120124.xlsx �E IDIAN-- APPROVED DATE 03/02/22 FIEF NUMBER PP-�...-oos. e rv"" i at Meridian - Area 8 us Area = Area = FArea = FArea = C Coefficient = Drainage System Characteristics System Infiltration Rate = Swale Top Area = Swale Bottom Area = Swale Depth = Swale Volume = Inf Trench Width = Inf Trench Length = Inf Trench Depth = Storage Volume of trench = Total Volume = Infiltration Area = Infiltration Rate = 11,645 sf 4,546 sf 16,191 sf 0.37 acres 0.74 8.00 in./hr - sf - sf 0.00 ft - cf 10.00 ft 50.00 ft 4.50 ft 900 cf 900 cf 500 sf 333 cf/hr Drainage Calculations Basin Developed Volume Prepared By: Riley Langan Date:09/28/2021 Project #: 120124 Storage Volume Required (100-yr Storm) (based on Zone "A" IDF Curve, 100-yr Return Period) Intensity Time (min) Time (sec):1 (in/hr) Q dev. (cfs) V dev. (cf) V inf. (cf) Vs (cf) 10 600 3.11 0.85 513 56 457 15 900 2.62 0.72 648 83 565 20 1,200 2.28 0.63 752 111 641 30 1,800 1.82 0.50 ................................................................................................................................................................................................................................ 900 167 734 40 2,400 1.37 0.38 904 222 681 50 .......................................................................................................... 3,000 1.17 0.32 .......................................................................................................................................................................................' 965 278 687 60 .......................................................................................................... 3,600 1.15 0.32 ....................................................................................................................................................................................... 1,138 333 120 .......................................................................................................... 7,200 0.66 0.18 ........................................................................................................................................................................................................................................... 1,306 667 639 180 .......................................................................................................... .10,800 0.48 0.13 ........................................................................................................................................................................................................................................... 1,425 1,000 425 360 ........................................................................................................... 21,600 0.30 0.08 ..................................................................................................................,.....................................................................e.................................................... 1,781 2,000 -219 720 43,200 1 0. 9 0.05 :............................................................................................................................................................................................... 2,256 4,000 -1,744 1...440 86 400 0.12 0.03 2,850 8,000 -5,150 System Checks Maximum Runoff Developed = 804 cf Total Volume Provided = 900 cf System OK (Excess Capacity) System Recovery Maximum Runoff = 804 cf Other Sources = 0 cf Percolation Volume = 804 cf Recovery Time = 2.4 hours System Summary: 10.00 ft wide x 4.50 ft deep x 50.00 ft long Sand & Grease Trap: 1500-Gal 1000-Gal Trap Size 1000-Gal 7.08 sf Maximum Discharge = 0.85 cfs System OK (Excess Capacity) Velocity = 0.06 fps Number of Traps = 2 CD Seasons at Meridian SeepageBedSizing 120124.xlsx �E IDIAN-- APPROVED DATE 03/02/22 FIEF NUMBER PP-�...-oos. e rv"" at Meridian - Area 9 us Area = Area = FArea = FArea = C Coefficient = Drainage System Characteristics System Infiltration Rate = Swale Top Area = Swale Bottom Area = Swale Depth = Swale Volume = Inf Trench Width = Inf Trench Length = Inf Trench Depth = Storage Volume of trench = Total Volume = Infiltration Area = Infiltration Rate = 27,454 sf 8,920 sf 36,374 sf 0.84 acres 0.77 8.00 in./hr - sf - sf 0.00 ft - cf 20.00 ft 40.00 ft 7.00 ft 2240 cf 2,240 cf 800 sf 533 cf/hr Drainage Calculations Basin Developed Volume Prepared By: Riley Langan Date:09/28/2021 Project #: 120124 Storage Volume Required (100-yr Storm) (based on Zone "A" IDF Curve, 100-yr Return Period) Intensity Time (min) Time (sec):1 (in/hr) Q dev. (cfs) V dev. (cf) V inf. (cf) Vs (cf) 10 ........................................................................... 600 3.11 1.99 ..................................................................................................................................................................................................................................................... 1,194 89 1,105 15 900 2.62 1.68 1,508 133 1,375 20 1,200 2.28 1.46 1,750 178 1,572 30 1,800 1.82 1.16 ................................................................................................................................................................................................................................ 2,096 267 1,829 40 .................................................................................................... 2,400 1.37 0.88 ..................................................................................................................................................................................................................................................... 2,103 356 1,748 50 .......................................................................................................... 3,000 1.17 0.75 .................................................................................................................................................................................................' 2,245 444 1,801 60 .......................................................................................................... 3,600 1.15 0.74 ................................................................................................................................................................................................. 2,648 533 120 .......................................................................................................... 7,200 0.66 0.42 ..................................................................................................................................................................................................................................................... 3,040 1,067 1,973 180 .......................................................................................................... .10,800 0.48 0.31 ..................................................................................................................................................................................................................................................... 3,316 1,600 1,716 360 ........................................................................................................... 21,600 0.30 0.19 ...................................................................................................................,.....................................................................e.................................................... 4,145 3,200 945 720 ........................................... . 43,200 1 0. 9 0.12 .....................................................................,.....................................................................,.................................................... 5,251 6,400 -1,149 1..440 8 6,400 0 12 0.08 6,632 12,800 -6,168 System Checks Maximum Runoff Developed = 2,115 cf Total Volume Provided = 2,240 cf System OK (Excess Capacity) System Recovery Maximum Runoff = 2,115 cf Other Sources = 0 cf Percolation Volume = 2,115 cf Recovery Time = 4.0 hours System Summary: 20.00 ft wide x 7.00 ft deep x 40.00 ft long Sand & Grease Trap: 1500-Gal 1000-Gal Trap Size 1000-Gal 7.08 sf Maximum Discharge = 1.99 cfs System OK (Excess Capacity) Velocity = 0.14 fps Number of Traps = 2 CD Seasons at Meridian SeepageBedSizing 120124.xlsx �E IDIAN-- APPROVED DATE 03/02/22 FIEF NUMBER PP-�...-oos. e rv"" at Meridian - Area 10 us Area = Area = FArea = FArea = C Coefficient = Drainage System Characteristics System Infiltration Rate = Swale Top Area = Swale Bottom Area = Swale Depth = Swale Volume = Inf Trench Width = Inf Trench Length = Inf Trench Depth = Storage Volume of trench = Total Volume = Infiltration Area = Infiltration Rate = 58,168 sf 7,876 sf 66,044 sf 1.52 acres 0.86 8.00 in./hr - sf - sf 0.00 ft - cf 12.00 ft 120.00 ft 8.00 ft 4608 cf 4,608 cf 1,440 sf 960 cf/hr Drainage Calculations Basin Developed Volume Prepared By: Riley Langan Date:09/28/2021 Project #: 120124 Storage Volume Required (100-yr Storm) (based on Zone "A" IDF Curve, 100-yr Return Period) Intensity Time (min) Time (sec):1 (in/hr) Q dev. (cfs) V dev. (cf) V inf. (cf) Vs (cf) 10 ........................................................................... 600 3.11 4.06 ..................................................................................................................................................................................................................................................... 2,435 160 2,275 15 900 2.62 3.42 3,077 240 2,837 20 1,200 2.28 2.97 3,570 320 3,250 30 1,800 1.82 2.37 ............................................................................................................................................................................................................................... 4,274 480 3,794 40 .................................................................................................... 2,400 1.37 1.79 .................................................................................................................................................................................................................................................... 4,290 640 3,650 50 3,000 1.17 1.53 ...........................................................................................................................................................................' 4,580 800 3,780 60 3,600 1.15 1.50 .......................................................................................................................................... 5,402 960 120 7,200 0.66 0.86 6,200 1,920 4,280 180 .......................................................................................................... .10,800 0.48 0.63 .................................................................................................................................................................................................................................................... 6,764 2,880 3,884 360 ........................................................................................................... 21,600 0.30 0.39 .................................................................................................................................................................................................e.................................................... 8,455 5,760 2,695 720 ...................................................1...440 43,200 1 0. 9 0.25 ......................................................:.....................................................................,......................................................................................................................... 10,709 11,520 -811 86 400 0.12 0.16 13,528 23,040 -9,512 System Checks Maximum Runoff Developed = 4,442 cf Total Volume Provided = 4,608 cf System OK (Excess Capacity) System Recovery Maximum Runoff = 4,442 cf Other Sources = 0 cf Percolation Volume = 4,442 cf Recovery Time = 4.6 hours System Summary: 12.00 ft wide x 8.00 ft deep x 120.00 ft long Sand & Grease Trap: 1500-Gal 1000-Gal Trap Size 1000-Gal 7.08 sf Maximum Discharge = 4.06 cfs System OK (Excess Capacity) Velocity = 0.29 fps Number of Traps = 2 CD Seasons at Meridian SeepageBedSizing 120124.xlsx �E IDIAN-- APPROVED DATE 03/02/22 FIEF NUMBER PP-�...-oos. e rv"" at Meridian - Area 11 us Area = Area = FArea = FArea = C Coefficient = Drainage System Characteristics System Infiltration Rate = Swale Top Area = Swale Bottom Area = Swale Depth = Swale Volume = Inf Trench Width = Inf Trench Length = Inf Trench Depth = Storage Volume of trench = Total Volume = Infiltration Area = Infiltration Rate = 58,240 sf 15,940 sf 74,180 sf 1.70 acres 0.79 8.00 in./hr - sf - sf 0.00 ft - cf 10.00 ft 135.00 ft 9.00 ft 4860 cf 4,860 cf 1,350 sf 900 cf/hr Drainage Calculations Basin Developed Volume Prepared By: Riley Langan Date:09/28/2021 Project #: 120124 Storage Volume Required (100-yr Storm) (based on Zone "A" IDF Curve, 100-yr Return Period) Intensity Time (min) Time (sec):1 (in/hr) Q dev. (cfs) V dev. (cf) V inf. (cf) Vs (cf) 10 ........................................................................... 600 3.11 4.18 ..................................................................................................................................................................................................................................................... 2,507 150 2,357 15 900 2.62 3.52 3,168 225 2,943 20 1,200 2.28 3.06 3,675 300 3,375 30 1,800 1.82 2.44 ............................................................................................................................................................................................................................... 4,401 450 3,951 40 .................................................................................................... 2,400 1.37 1.84 .................................................................................................................................................................................................................................................... 4,417 600 3,817 50 3,000 1.17 1.57 ...........................................................................................................................................................................' 4,715 750 3,965 60 3,600 1.15 1.54 .......................................................................................................................................... 5,561 900 120 7,200 0.66 0.89 6,384 1,800 4,584 180 .......................................................................................................... .10,800 0.48 0.64 .................................................................................................................................................................................................................................................... 6,964 2,700 4,264 360 ........................................................................................................... 21,600 0.30 0.40 .................................................................................................................................................................................................e.................................................... 8,705 5,400 3,305 720 ...................................................1...440 43,200 1 0. 9 0.26 ......................................................:.....................................................................,......................................................................................................................... 11,026 10,800 226 86 400 0.12 0.16 13,928 21,600 -7,672 System Checks Maximum Runoff Developed = 4,661 cf Total Volume Provided = 4,860 cf System OK (Excess Capacity) System Recovery Maximum Runoff = 4,661 cf Other Sources = 0 cf Percolation Volume = 4,661 cf Recovery Time = 5.2 hours System Summary: 10.00 ft wide x 9.00 ft deep x 135.00 ft long Sand & Grease Trap: 1500-Gal 1000-Gal Trap Size 1000-Gal 7.08 sf Maximum Discharge = 4.18 cfs System OK (Excess Capacity) Velocity = 0.29 fps Number of Traps = 2 CD Seasons at Meridian SeepageBedSizing 120124.xlsx �E IDIAN-- APPROVED DATE 03/02/22 FIEF NUMBER PP-�...-oos. e rv"" at Meridian - Area 12 us Area = Area = FArea = FArea = C Coefficient = Drainage System Characteristics System Infiltration Rate = Swale Top Area = Swale Bottom Area = Swale Depth = Swale Volume = Inf Trench Width = Inf Trench Length = Inf Trench Depth = Storage Volume of trench = Total Volume = Infiltration Area = Infiltration Rate = 47,618 sf 8,985 sf 56,603 sf 1.30 acres 0.83 8.00 in./hr - sf - sf 0.00 ft - cf 10.00 ft 115.00 ft 9.00 ft 4140 cf 4,140 cf 1,150 sf 767 cf/hr Drainage Calculations Basin Developed Volume Prepared By: Riley Langan Date:09/28/2021 Project #: 120124 Storage Volume Required (100-yr Storm) (based on Zone "A" IDF Curve, 100-yr Return Period) Intensity Time (min) Time (sec):1 (in/hr) Q dev. (cfs) V dev. (cf) V inf. (cf) Vs (cf) 10 ........................................................................... 600 3.11 3.36 ..................................................................................................................................................................................................................................................... 2,015 128 1,887 15 900 2.62 2.83 2,546 192 2,354 20 1,200 2.28 2.46 2,954 256 2,699 30 1,800 1.82 1.97 ................................................................................................................................................................................................................................ 3,537 383 3,154 40 .................................................................................................... 2,400 1.37 1.48 ..................................................................................................................................................................................................................................................... 3,550 511 3,039 50 .......................................................................................................... 3,000 1.17 1.26 .................................................................................................................................................................................................' 3,790 639 3,151 60 .......................................................................................................... 3,600 1.15 1.24 ................................................................................................................................................................................................. 4,470 767 120 .......................................................................................................... 7,200 0.66 0.71 ..................................................................................................................................................................................................................................................... 5,131 1,533 3,598 180 .......................................................................................................... .10,800 0.48 0.52 ..................................................................................................................................................................................................................................................... 5,597 2,300 3,297 360 ........................................................................................................... 21,600 0.30 0.32 .................................................................................................................................................................................................e.................................................... 6,997 4,600 2,397 720 43,200 1 0. 9 0.21 :............................................................................................................................................................................................... 8,863 9,200 -337 1...440 86 400 0.12 0.13 11,195 18,400 -7,205 System Checks Maximum Runoff Developed = 3,704 cf Total Volume Provided = 4,140 cf System OK (Excess Capacity) System Recovery Maximum Runoff = 3,704 cf Other Sources = 0 cf Percolation Volume = 3,704 cf Recovery Time = 4.8 hours System Summary: 10.00 ft wide x 9.00 ft deep x 115.00 ft long Sand & Grease Trap: 1500-Gal 1000-Gal Trap Size 1000-Gal 7.08 sf Maximum Discharge = 3.36 cfs System OK (Excess Capacity) Velocity = 0.24 fps Number of Traps = 2 CD Seasons at Meridian SeepageBedSizing 120124.xlsx �E IDIAN-- APPROVED DATE 03/02/22 FIEF NUMBER PP-�...-oos. e rv"" at Meridian - Area 13 us Area = Area = FArea = FArea = C Coefficient = Drainage System Characteristics System Infiltration Rate = Swale Top Area = Swale Bottom Area = Swale Depth = Swale Volume = Inf Trench Width = Inf Trench Length = Inf Trench Depth = Storage Volume of trench = Total Volume = Infiltration Area = Infiltration Rate = 35,752 sf 14,276 sf 50,028 sf 1.15 acres 0.74 8.00 in./hr - sf - sf 0.00 ft - cf 10.00 ft 95.00 ft 8.00 ft 3040 cf 3,040 cf 950 sf 633 cf/hr Drainage Calculations Basin Developed Volume Prepared By: Riley Langan Date:09/28/2021 Project #: 120124 Storage Volume Required (100-yr Storm) (based on Zone "A" IDF Curve, 100-yr Return Period) Intensity Time (min) Time (sec):1 (in/hr) Q dev. (cfs) V dev. (cf) V inf. (cf) Vs (cf) 10 ........................................................................... 600 3.11 2.63 ..................................................................................................................................................................................................................................................... 1,577 106 1,472 15 900 2.62 2.21 1,993 158 1,835 20 1,200 2.28 1.93 2,313 211 2,102 30 1,800 1.82 1.54 ................................................................................................................................................................................................................................ 2,769 317 2,452 40 .................................................................................................... 2,400 1.37 1.16 ..................................................................................................................................................................................................................................................... 2,779 422 2,357 50 3,000 1.17 0.99 2,967 ................i.....................................................................' 528 2,439 60 .......................................................................................................... 3,600 1.15 0.97 ................................................................................................................................................................................................. 3,499 633 120 .......................................................................................................... 7,200 0.66 0.56 ..................................................................................................................................................................................................................................................... 4,017 1,267 2,750 180 .......................................................................................................... .10,800 0.48 0.41 ..................................................................................................................................................................................................................................................... 4,382 1,900 2,482 360 ........................................................................................................... 21,600 0.30 0.25 ...........................................................................................................................................................................................e.................................................... 5,477 3,800 1,677 720 43,200 1 0. 9 0.16 ............................................................................................................................................................................................... 6,938 7,600 -662 1...440 86 400 0.12 0.10 8,764 15,200 -6,436 System Checks Maximum Runoff Developed = 2,866 cf Total Volume Provided = 3,040 cf System OK (Excess Capacity) System Recovery Maximum Runoff = 2,866 cf Other Sources = 0 cf Percolation Volume = 2,866 cf Recovery Time = 4.5 hours System Summary: 10.00 ft wide x 8.00 ft deep x 95.00 ft long Sand & Grease Trap: 1500-Gal 1000-Gal Trap Size 1000-Gal 7.08 sf Maximum Discharge = 2.63 cfs System OK (Excess Capacity) Velocity = 0.19 fps Number of Traps = 2 CD Seasons at Meridian SeepageBedSizing 120124.xlsx E APPROVED DATE: 03/02/22 , FILE NUMBERFc-zo I, D57 Pervious at Meridian - Area 14 us Area = Area = FArea = FArea = C Coefficient = Drainage System Characteristics System Infiltration Rate = Swale Top Area = Swale Bottom Area = Swale Depth = Swale Volume = Inf Trench Width = Inf Trench Length = Inf Trench Depth = Storage Volume of trench = Total Volume = Infiltration Area = Infiltration Rate = Drainage Calculations Basin Developed Volume Prepared By: Riley Langan 24,064 sf Date:09/28/2021 12,098 sf Project #: 120124 36,162 sf 0.83 acres 0.70 8.00 in./hr - sf - sf 0.00 ft - cf 10.00 ft 100.00 ft 5.00 ft 2000 cf 2,000 cf 1,000 sf 667 cf/hr Storage Volume Required (100-yr Storm) (based on Zone "A" IDF Curve, 100-yr Return Period) Intensity Time (min) Time (sec) (in/hr) Q dev. (cfs) V dev. (cf) V inf. (cf) Vs (cf) 10 ................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................. 600 3.11 1.80 1,083 111 972 15 900 2.62 1.52 1,368 167 1,202 20 ......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... 1,200 2.28 1.32 1,588 222 1,366 30 ................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................. 1,800 1.82 1.06 1,901 333 1,568 40 ................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................. 2,400 1.37 0.80 1,908 444 1,464 50 3,000 1.17 0.68 2,037 556 1,482 .........................................................fio...........................................................................3..600.........................................1.15 .........................................................................................................................:......................... r...................................;..............................................................:...............................................................' ............................................0.67 .............................................2,403 ..403.................. r.......................................:.....................................................................�.................... .......................667...................... ...736.. 120 ................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................. 7,200 0.66 0.38 2,758 1,333 1,425 180 ................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................. 10,800 0.48 0.28 3,009 2,000 1,009 360 ......................................................720....................................................,..................43 21,600 0.30 0.17 ,.1.1.............................................4...764..............................................8..000......................e..............3...2.3.C............. 3,761 4,000 -239 .......................................................................................................................................................................................;................................................................................................................................................................................ 200........................................0.19.............................................o ................................................. ............................... 1,440 86,400 0.12 0.07 6,017 16,000 -9,983 System Checks Maximum Runoff Developed = 1,736 cf Total Volume Provided = 2,000 cf System OK (Excess Capacity) System Recovery Maximum Runoff = 1,736 cf Other Sources = 0 cf Percolation Volume = 1,736 cf Recovery Time = 2.6 hours System Summary 10.00 ft wide x 5.00 ft deep x 100.00 ft long Sand & Grease Trap: 1500-Gal 1000-Gal Trap Size 1000-Gal 7.08 sf Maximum Discharge = 1.80 cfs System OK (Excess Capacity) Velocity = 0.13 fps Number of Traps = 2 CD Seasons at Meridian Seepage Bed Sizing 120124.xlsx L �1E IDIAN — ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method APPROVED is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These 03/02/22 p4TE blish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. FILE NUMBER:Fc-s 1s Ds7 Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Seasons at Meridian 2 Is area drainage basin map provided? (map must be included with stormwater calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 4 Enter number of storage facilities (25 max) 5 Area of Drainage Subbasin (SF or Acres) SF Acre. 6 Determine the Weighted Runoff Coefficient (C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 user Calculate min io Min- 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc 9 Calculate the Post -Development peak discharge (QPeak) i QPeak 2.58 0.72 in hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) MEr 959 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm 1 (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) V" 599 ft 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 96 fts Primary Treatment/Storage Basin V 863 fts Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 959 ft' YES flirk to Chnw Mnra Siihhacinc F-1 Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 Subbasin 6 7 8 9 10 12,376 1,625 0.32 0.95 0.20 0.86 Estimated Runoff Coefficients for Various Surface Type of Surface Runoff Coefficients "I Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 0.07 1 0. Average: 2-6% 0.09 0.12 0.15 0. Steep:>6% 0.13 0.18 0.23 0. Adapted from ASCE G:\2020\120124\CAD\Calcs and Reports\Storm\SD Report Supporting Documents\Seasons at Meridian ACHD SD Calcs 120124.xism Version 10.5, November 2018 9/28/2021,9:28 AM 1 E IDIAN — ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method APPROVED is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These DATE 03/02/22 blish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. FILE NUMBER: ra-zozvoon ost-Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Seasons at Meridian, Facility 2 2 Is area drainage basin map provided? YES (map must be included with storm water calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient(C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 user Calculate min 10 Min- 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 2.58 1.22 in hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 1,640 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) Vrr 1,025 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 164 ft' Primary Treatment/StorageBasin V 1,476 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 1,640 ft' Clirk to Shnw MnrP Snhhacinc F-1 Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 Subbasin 6 7 8 9 10 21,006 3,574 0.56 0.95 0.20 0.84 Estimated Runoff Coefficients for Various Surfao Type of Surface Runoff Coefficients "F Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 0.07 0.11 0. Average: 2-6% 0.09 0.12 0.15 0. Steep:>6% 0.13 0.18 0.23 0. Adapted from ASCE G:\2020\120124\CAD\Calcs and Reports\Storm\SD Report Supporting Documents\Seasons at Meridian ACHD SD Calcs 120124.xlsm 9/28/2021, 9:28 AM Version 10.5, November 2018 1 E IDIAN — ACHD Calculation Sheet for Finding Peak Discharge/Volume - Rational Method APPROVED is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These DATE 03/02/22 blish a minimum requirement. The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. FILE NUMBER: ra-zozvoon ost-Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Seasons at Meridian, Facility 3 2 Is area drainage basin map provided? YES (map must be included with storm water calculations) 3 Enter Design Storm (100-Year or 25-Year With 100-Year Flood Route) 100 5 Area of Drainage Subbasin (SF or Acres) SF Acre 6 Determine the Weighted Runoff Coefficient(C) C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 7 Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10 user Calculate min 10 Min- 8 Determine the average rainfall intensity (i) from IDF Curve based on Tc i 9 Calculate the Post -Development peak discharge (QPeak) Qpeak 2.58 1.34 in hr cfs 10 Calculate total runoff vol (V) (for sizing primary storage) V 1,800 ft V = Ci (Tc=60)Ax3600 11 Calculate Volume of Runoff Reduction Vrr Enter Percentile Storm I (95th percentile = 0.60 in) 95th 0.60 in Enter Runoff Reduction Vol (95th Percentile=0.60-in x Area x C) Vrr 1,125 W 12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs 13 Volume Summary Surface Storage: Basin Basin Forebay V 180 ft' Primary Treatment/StorageBasin V 1,620 ft' Subsurface Storage Volume Without Sediment Factor (See BMP 20 Tab) V 1,800 ft' Clirk to Shnw MnrP Snhhacinc F-1 Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 Subbasin 6 7 8 9 10 22,268 7,686 0.69 0.95 0.20 0.76 Estimated Runoff Coefficients for Various Surfao Type of Surface Runoff Coefficients "F Business Downtown areas 0.70-0.95 Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 Multi -family 0.60-0.75 Residential (rural) 0.25-0.40 Apartment Dwelling Areas 0.70 Industrial and Commercial Light areas 0.80 Heavy areas 0.90 Parks, Cemeteries 0.10-0.25 Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 Unimproved areas 0.10-0.30 Streets Asphalt 0.95 Concrete 0.95 Brick 0.95 Roofs 0.95 Gravel 0.75 Fields: Sandy soil Soil Type Slope A B C D Flat: 0-2% 0.04 0.07 0.11 0. Average: 2-6% 0.09 0.12 Steep:>6% 0.13 0.18 0.23 0. Adapted from ASCE G:\2020\120124\CAD\Calcs and Reports\Storm\SD Report Supporting Documents\Seasons at Meridian ACHD SD Calcs 120124.xlsm 9/28/2021, 9:28 AM Version 10.5, November 2018 CUEIDR IAN,-- �� HD Calculation Sheet for Sizing Seepage Bed With Optional Chambers APPROVED t is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the In methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in 03/02/22 exceed these calculations in order to be accepted. DATE t pulls information from the "Peak QV" tab FILE NUMBER' PP-2o21-11 ost-Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Seasons at Meri 2 Enter number of Seepage Beds (25 max) 3 Design Storm 4 Weighted Runoff Coefficient C 5 Area A (Acres) 6 Approved discharge rate (if applicable) 7 Is Seepage Bed in Common Lot? No Bed A 1 100 0.86 0.32 acres 0.00 cfs V 1,198 Linkto: Q'V Q Vz Q,V3 QV TR55 ft3 25%Sediment 8 Set Total Design Width of All Drain Rock W 10.0 ft 9 Set Total Design Depth of All Drain Rock D 3.3 ft Rock Only, Do Not Include Filter Sand Depth or Cover 10 Void Ratio of Drain Rock Voids 0.4 0.4 for 1.5"-2" drain rock and 3/4" Chips 11 Design Infiltration Rate (8 in/hr max) Perc 8.00 in/hr 12 Size of WQ Perf Pipe (Pert 180°) Dia pipe 18 in 13 Size of Overflow Perf Pipe (Perfs 360°), REQD if Q100>3.3 cfs in 14 Calculate Total Storage per Foot Spf 20.0 ft3/ft 15 Calculate Design Length L 0 60 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 60 ft 17 Variable Infiltration Window W SWW 10.0 ft 18 Time to Drain 2.7 hours 90%volume in 48-hours minimum 19 Length of WQ & Overflow Perf Pipes 60 ft 20 Perf Pipe Checks. Qperf>= Qpeak; where Qperf=CdxAxJ(2xgxH) upnonai morage Lnamoers This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume, Without Rock, Per Manuf 45.90 ft3 6 Chamber Storage Volume, With Rock, Per Manuf 74.90 ft3 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ft2 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90%volume in 48-hours minimum G:\2020\120124\CAD\Calcs and Reports\Storm\SD Report Supporting Documents\Seasons at Meridian ACHD SD Calcs 120124.x1sm 9/28/2021, 9:28 AM Version 10.0, May 2018 CUEIDR IAN,-- �� HD Calculation Sheet for Sizing Seepage Bed With Optional Chambers APPROVED t is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the In methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in 03/02/22 exceed these calculations in order to be accepted. DATE t pulls information from the "Peak QV" tab FILE NUMBER:ost-Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Seasons at Meri 2 Enter number of Seepage Beds (25 max) 3 Design Storm 4 Weighted Runoff Coefficient C 5 Area A (Acres) 6 Approved discharge rate (if applicable) 7 Is Seepage Bed in Common Lot? No Bed B 1 100 0.84 0.56 acres 0.00 cfs V 2,050 Link to: Q•v Q,Vz� Q,V3 QV TR55 ft3 25%Sediment 8 Set Total Design Width of All Drain Rock W 10.0 ft 9 Set Total Design Depth of All Drain Rock D 7.0 ft Rock Only, Do Not Include Filter Sand Depth or Cover 10 Void Ratio of Drain Rock Voids 0.4 0.4 for 1.5"-2" drain rock and 3/4" Chips 11 Design Infiltration Rate (8 in/hr max) Perc 8.00 in/hr 12 Size of WQ Perf Pipe (Pert 180°) Dia pipe 18 in 13 Size of Overflow Perf Pipe (Perfs 360°), REQD if Q100>3.3 cfs in 14 Calculate Total Storage per Foot Spf 34.8 ft,/ft 15 Calculate Design Length L 0 60 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 60 ft 17 Variable Infiltration Window W SWW 10.0 ft 18 Time to Drain 4.6 hours 90%volume in 48-hours minimum 19 Length of WQ & Overflow Perf Pipes 60 ft 20 Perf Pipe Checks. Qperf>= Qpeak; where Qperf=CdxAxV(2xgxH) Optional Storage Chambers This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume, Without Rock, Per Manuf 45.90 ft3 6 Chamber Storage Volume, With Rock, Per Manuf 74.90 ft3 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ftz 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90%volume in 48-hours minimum G:\2020\120124\CAD\Calcs and Reports\Storm\SD Report Supporting Documents\Seasons at Meridian ACHD SD Calcs 120124.xism 9/28/2021, 9:28 AM Version 10.0, May 2018 L �1E IDIAN — HD Calculation Sheet for Sizing Seepage Bed With Optional Chambers APPROVED t is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the In methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in DATL 03/02/22 exceed these calculations in order to be accepted. t pulls information from the "Peak QV" tab FILE NUMBER: re-2r21-.11 ost-Development Flows (for pre -development flows, increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Seasons at Meri 2 Enter number of Seepage Beds (25 max) 3 Design Storm 4 Weighted Runoff Coefficient C 5 Area A (Acres) 6 Approved discharge rate (if applicable) 7 Is Seepage Bed in Common Lot? No Bed C 1 100 0.76 0.69 acres 0.00 cfs V 2,250 Linkto: Qv Qvz� QV3 QV TR55 ft 25%Sediment 8 Set Total Design Width of All Drain Rock W 6.0 ft 9 Set Total Design Depth of All Drain Rock D 10.0 ft Rock Only, Do Not Include Filter Sand Depth or Cover 10 Void Ratio of Drain Rock Voids 0.4 0.4 for 1.5"-2" drain rock and 3/4" Chips 11 Design Infiltration Rate (8 in/hr max) Perc 8.00 in/hr 12 Size of WQ Perf Pipe (Pert 180°) Dia pipe 18 in 13 Size of Overflow Perf Pipe (Perfs 360% READ if Q100>3.3 cfs in 14 Calculate Total Storage per Foot Spf 28.2 ft3/ft 15 Calculate Design Length L 0 80 ft Override Value Required for Chambers 16 Variable Infiltration Window L SWL 80 ft 17 Variable Infiltration Window W SWW 6.0 ft 18 Time to Drain 6.3 hours 90%volume in 48-hours minimum 19 Length of WQ & Overflow Perf Pipes 80 ft 20 Perf Pipe Checks. Qperf>= Qpeak; where Qperf=CdxAxJ(2xgxH) upnonai morage Lnamoers This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 ft3 3 Installed Chamber Width Cw 4.25 ft Installed Chamber Depth Cd 2.50 ft Installed Chamber Height Ch 7.12 ft 4 Chamber Void Factor 5 Chamber Storage Volume, Without Rock, Per Manuf 45.90 ft3 6 Chamber Storage Volume, With Rock, Per Manuf 74.90 ft3 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ft2 9 Volume Infiltration Vperc 0 ft3/hr 10 Time to Drain hours 90%volume in 48-hours minimum G:\2020\120124\CAD\Calcs and Reports\Storm\SD Report Supporting Documents\Seasons at Meridian ACHD SD Calcs 120124.x1sm 9/28/2021, 9:28 AM Version 10.0, May 2018 �E IDR IAN,-- �� ACHD Calculation Sheet for Sand/Grease Traps APPROVED ksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the DATE 03/02/22 lation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must fllE NUMBER: —D .005 s that meet or exceed these calculations in order to be accepted. Trap Velocity Calculation User input in yellow cells. 1 Project Name Seasons at Meridian, S&G-A Enter number of Sand/Grease Traps 1 Number of Peak Flow Baffle Throat Velocity Is the Vault Size Spacing width Area (ft2) 0.5 fps Velocity S/G Traps Q-cfs inch inch max. ok? 1000 G 1 0.715612 20 51 7.08 0.10 Reference for Throat widths (inch) ADS Boise Lar-ken WQU, Vault BMP 16 1000 G 48.0 50.5 n/a 1500 G 60.0 61.5 n/a WQU1000 n/a n/a 60 WQU1500 n/a n/a 60 G:\2020\120124\CAD\Calcs and Reports\Storm\SD Report Supporting Documents\Seasons at Meridian ACHD SD Calc9/2ZV204 lkr28 AM Version 10.0, May 2018 �E IDR IAN,-- �� ACHD Calculation Sheet for Sand/Grease Traps APPROVED ksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the DATE 03/02/22 lation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must fllE NUMBER: —D .005 s that meet or exceed these calculations in order to be accepted. User input in yellow cells. 1 Project Name Seasons at Meridian, S&G-B Enter number of Sand/Grease Traps 1 Number of Peak Flow Baffle Throat Velocity Is the Vault Size Spacing width Area (ft2) 0.5 fps Velocity S/G Traps Q-cfs inch inch max. ok? 1000 G 1 1.224286 20 51 7.08 0.17 Reference for Throat widths (inch) ADS Boise Lar-ken WQU, Vault BMP 16 1000 G 48.0 50.5 n/a 1500 G 60.0 61.5 n/a WQU1000 n/a n/a 60 WQU1500 n/a n/a 60 G:\2020\120124\CAD\Calcs and Reports\Storm\SD Report Supporting Documents\Seasons at Meridian ACHD SD Calc9/2ZV204 lkr28 AM Version 10.0, May 2018 �E IDR IAN,-- �� ACHD Calculation Sheet for Sand/Grease Traps APPROVED ksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the DATE 03/02/22 lation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must fllE NUMBER: —D .005 s that meet or exceed these calculations in order to be accepted. User input in yellow cells. 1 Project Name Seasons at Meridian, S&G-C Enter number of Sand/Grease Traps 1 Number of Peak Flow Baffle Throat Velocity Is the Vault Size Spacing width Area (ft2) 0.5 fps Velocity S/G Traps Q-cfs inch inch max. ok? 1000 G 1 1.344005 20 51 7.08 0.19 Reference for Throat widths (inch) ADS Boise Lar-ken WQU, Vault BMP 16 1000 G 48.0 50.5 n/a 1500 G 60.0 61.5 n/a WQU1000 n/a n/a 60 WQU1500 n/a n/a 60 G:\2020\120124\CAD\Calcs and Reports\Storm\SD Report Supporting Documents\Seasons at Meridian ACHD SD Calc9/2ZV204 lkr28 AM Version 10.0, May 2018 Seasons at Meridian 2700 E. Overland Road, Meridian, ID 83642 Storm Water Management & Engineered Drainage Report APPROVED DA EI 03/02/22 endix C Geotechnical Report THE LAND GROUP L �1E IDIAN APPROVED DATE: 03/02/22 FILE NUMBER: FP-zozvoon y V GEOTECHNICAL INVESTIGATION PROPOSED MIXED -USE DEVELOPMENT 2700 East Overland Road Meridian, ID PREPARED FOR: Mr. Blake Morgan Morgan Holdings, LLC 2223 Avenida de la Playa, Suite 350 La Jolla, CA 92037 PREPARED BY: Atlas Technical Consultants, LLC 2791 South Victory View Way Boise, ID 83709 bber 19, 2020 B201400g CUEIDR IAyrati APPROVEDDATE 03/02/22 y m FIEF NUMBER: FP-��21-oos1 October 19, 2020 Atlas No. B201400g Mr. Blake Morgan Morgan Holdings, LLC 2223 Avenida de la Playa, uite 350 La Jolla, CA 92037 Subject: GeotechnicalInvestigation Proposed Mixed -Use Development 2700 East Overland Road Meridian, ID Dear Mr. Morgan: In compliance with your instructions, Atlas has conducted a soils exploration and foundation evaluation for the above referenced development. Fieldwork for this investigation was conducted on October 5, 2020. Data have been analyzed to evaluate pertinent geotechnical conditions. Results of this investigation, together with our recommendations, are to be found in the following report. We have provided a PDF copy for your review and distribution. Often, questions arise concerning soil conditions because of design and construction details that occur on a project. Atlas would be pleased to continue our role as geotechnical engineers during project implementation. If you have any questions, please call us at (208) 376-4748. Respectfully submitted, Weston Jorgenson, GIT taff Geologist Monica aculles, PE enior Geotechnical o��SSor, NSFoN�/yF Q� 14919 10-19-20 '11��9TF 0 F �� SAOV/ Page 1 CUEIDR IAy APPROVED DATE: 03/02/22 FILE NUMBER: Fa- D -DDs1 CONTENTS 1. INTRODUCTION................................................................................................................. 1 1.1 Project Description..................................................................................................... 1 1. Authorization.............................................................................................................. 1 1.3 Scope of Investigation................................................................................................ 1 2. SITE DESCRIPTION........................................................................................................... 2 .1 Site Access................................................................................................................ RegionalGeology....................................................................................................... .3 General Site Characteristics....................................................................................... .4 Regional Site Climatology and Geochemistry............................................................. 3 SEISMIC SITE EVALUATION............................................................................................ 3 3.1 Geoseismic Setting.................................................................................................... 3 3. Seismic Design Parameter Values............................................................................. 3 4. SOILS EXPLORATION............ .................................................................................. 4.1 Exploration and Sampling Procedures........................................................................ 4 4. Laboratory Testing Program....................................................................................... 4 4.3 Soil and Sediment Profile........................................................................................... 5 4.4 Volatile Organic Scan................................................................................................. 5 5. SITE HYDROLOGY............................................................................................................ 5 5.1 Groundwater.............................................................................................................. 5 5. Soil Infiltration Rates.................................................................................................. 6 6. FOUNDATION AND SLAB DISCUSSION AND RECOMMENDATIONS ............................ 6 6.1 Foundation Design Recommendations....................................................................... 7 6. Foundation Drain Recommendations......................................................................... 8 6.3 Floor Slab-on-Grade................................................................................................... 8 7. PAVEMENT DISCUSSION AND RECOMMENDATIONS................................................. 7.1 Flexible Pavement Sections....................................................................................... 9 7. Pavement Subgrade Preparation..............................................................................10 7.3 Common Pavement Section Construction Issues......................................................10 8. CONSTRUCTION CONSIDERATIONS ........................................................................ 8.1 Earthwork..................................................................................................................10 8. Dry Weather..............................................................................................................11 8.3 Wet Weather.............................................................................................................11 8.4 Soft Subgrade Soils...................................................................................................11 8.5 Frozen Subgrade Soils..............................................................................................1 8.6 Structural Fill.............................................................................................................1 8.7 Backfill of Walls.........................................................................................................13 8.8 Excavations...............................................................................................................14 Atlas No. B 01400g Page I i Copyright © 0 0 Atlas Technical Consultants CUEIDR IAy C APPROVED oaTe osiozizz GroundwaterControl.................................................................................................14 fllE NUMBER: Fa-zozi-oo51 ERALCOMMENTS....................................................................................................15 10. REFERENCES.................................................................................................................16 TA of me Table 1 — Seismic Design Values................................................................................................4 Table— Groundwater Data.......................................................................................................6 Table 3 — Soil Bearing Capacity..................................................................................................7 Table 4 — AASHTO Flexible Pavement Specifications.................................................................9 APPENDICES Appendix I Warranty and Limiting Conditions Appendix II Vicinity Map Appendix III Site Map Appendix IV Geotechnical Investigation Test Pit Log Appendix V Geotechnical General Notes Appendix VI AASHTO Pavement Thickness Design Procedures Appendix VI Important Information About This Geotechnical Engineering Report Atlas No. B 01400g Page I ii Copyright © 0 0 Atlas Technical Consultants CUEIDR IAy APPROVED I DATE 03/02/22 FILE NUMBF R: FP-zozvoon RODUCTION This report presents results of a geotechnical investigation and analysis in support of data utilized in design of structures as defined in the 015 International Building Code (IBC). Information in support of groundwater and stormwater issues pertinent to the practice of Civil Engineering is included. Observations and recommendations relevant to the earthwork phase of the project are also presented. Revisions in plans or drawings for the proposed development from those enumerated in this report should be brought to the attention of the soils engineer to determine whether changes in the provided recommendations are required. Deviations from noted subsurface conditions, if encountered during construction, should also be brought to the attention of the soils engineer. 1.1 Project Description The proposed development is in the southern portion of the City of Meridian, Ada County, ID, and occupies a portion of the SVV'/4SE'/4 of Section 17, Township 3 North, Range 1 East, Boise Meridian. This project will consist of construction of several 3-story, multi -family apartment structures and a series of retail structures to be developed on approximately 15.885 acres. Total settlements are limited to 1 inch. Loads of up to 4,000 pounds per lineal foot for wall footings, and column loads of up to 50,000 pounds were assumed for settlement calculations. Additionally, assumptions have been made for traffic loading of pavements. Retaining walls are not anticipated as part of the project. Atlas has not been informed of the proposed grading plan. 1.2 Authorization Authorization to perform this exploration and analysis was given in the form of a written authorization to proceed from Mr. Blake Morgan of Morgan Holdings, LLC to Elizabeth Brown of Atlas Technical Consultants (Atlas), on August 5, 0 0. Said authorization is subject to terms, conditions, and limitations described in the Professional Services Contract entered into between Morgan Holdings, LLC and Atlas. Our scope of services for the proposed development has been provided in our proposal dated August 18, 0 0 and repeated below. 1.3 Scope of Investigation The scope of this investigation included review of geologic literature and existing available geotechnical studies of the area, visual site reconnaissance of the immediate site, subsurface exploration of the site, field and laboratory testing of materials collected, and engineering analysis and evaluation of foundation materials. The scope of work did not include design recommendations specific to individual structures. Atlas No. B 01400g Page11 Copyright © 0 0 Atlas Technical Consultants CUEIDR IAy APPROVED DATE 03/02/22 EaENUMBER: FP-zoz,-oo5 E DESCRIPTION Access Access to the site may be gained via Interstate 84 to the Eagle Road exit. Proceed south on Eagle Road and immediately turn west on Overland Road. Travel west on Overland Road approximately 0.3 mile to the site, which is situated to the north of the roadway. The location is depicted on site map plates included in the Appendix. 2.2 Regional Geology The project site is located within the western Snake River Plain of southwestern Idaho and eastern Oregon. The plain is a northwest trending rift basin, about 45 miles wide and 00 miles long, that developed about 14 million years ago (Ma) and has since been occupied sporadically by large inland lakes. Geologic materials found within and along the plain's margins reflect volcanic and fluvial/lacustrine sedimentary processes that have led to an accumulation of approximately 1 to km of interbedded volcanic and sedimentary deposits within the plain. Along the margins of the plain, streams that drained the highlands to the north and south provided coarse to fine-grained sediments eroded from granitic and volcanic rocks, respectively. About million years ago the last of the lakes was drained and since that time fluvial erosion and deposition has dominated the evolution of the landscape. The project site is underlain by "Gravel of Sunrise Terrace" as mapped by Othberg and Stanford (1993). The Sunrise terrace is the third terrace above the modern Boise River in the eastern Boise Valley, composed of sandy pebble and cobble gravel, and is about 115 feet above river level. Quaternary faulting has probably truncated and tilted this terrace along with older surfaces. The surface of this deposit is mantled with 3-7 feet of loess containing a weakly to moderately developed duripan. Based on stratigraphic correlation the Sunrise terrace may be correlative with the Wilder terrace further to the west. 2.3 General Site Characteristics The site to be developed is approximately 15.885 acres in size. Currently, the site exists as an agricultural field. At the present time, vegetation on the site is limited to weeds and grasses along the north, east, and south property edges. The site is relatively flat and level. Regional drainage is north and west toward the Boise River. Stormwater drainage for the site is achieved by percolation through surficial soils. The site is situated so that it is unlikely that it will receive any drainage from off -site sources. Stormwater drainage collection and retention systems are not in place on the project site, but currently exist within the vicinity of the project site in the form of curbs, gutters, and drain inlets on Overland Road. Atlas No. B 01400g Pagel Copyright © 0 0 Atlas Technical Consultants CUEIDR IAy rgionalSite APPROVEDDATE 03/02/22 FIIF NUMBER: FP-D21-s1 Climatology and Geochemistry ccor ing to the Western Regional Climate Center, the average precipitation for the Treasure Valley is on the order of 10 to 1 inches per year, with an annual snowfall of approximately 0 inches and a range from 3 to 49 inches. The monthly mean daily temperatures range from 1°F to 950F, with daily extremes ranging from roughly - 5°F to 111 OF. Winds are generally from the northwest or southeast with an annual average wind speed of approximately 9 miles per hour (mph) and a maximum of 6 mph. Soils and sediments in the area are primarily derived from siliceous materials and exhibit low electro-chemical potential for corrosion of metals or concretes. Local aggregates are generally appropriate for Portland cement and lime cement mixtures. Surface water, groundwater, and soils in the region typically have pH levels ranging from 7. to 8. . 3. SEISMIC SITE EVALUATION 3.1 Geoseismic Setting Soil on site are classed as Site Class D in accordance with Chapter 0 of the American Society of Civil Engineers (ASCE) publication ASCE/SEI 7-10. Structures constructed on this site should be designed per IBC requirements for such a seismic classification. Our investigation did not reveal hazards resulting from potential earthquake motions including: slope instability, liquefaction, and surface rupture caused by faulting or lateral spreading. Incidence and anticipated acceleration of seismic activity in the area is low. 3.2 Seismic Design Parameter Values The United States Geological Survey National Seismic Hazard Maps ( 008), includes a peak ground acceleration map. The map for % probability of exceedance in 50 years in the Western United States in standard gravity (g) indicates that a peak ground acceleration of 0.180 is appropriate for the project site based on a Site Class D. The following section provides an assessment of the earthquake -induced earthquake loads for the site based on the Risk -Targeted Maximum Considered Earthquake (MCER). The MCER spectral response acceleration for short periods, SMs, and at 1-second period, SMI, are adjusted for site class effects as required by the 015 IBC. Design spectral response acceleration parameters as presented in the 015 IBC are defined as a 5% damped design spectral response acceleration at short periods, SDs, and at 1-second period, SDI• The USGS National Seismic Hazards Mapping Project includes a program that provides values for ground motion at a selected site based on the same data that were used to prepare the USGS ground motion maps. The maps were developed using attenuation relationships for soft rock sites; the source model, assumptions, and empirical relationships used in preparation of the maps are described in Petersen and others (1996). Atlas No. B 01400g Page13 Copyright © 0 0 Atlas Technical Consultants L 1E IDIAN — APPROVED �� 03/02/22 DATL_NUMBER:/02/ 2 s, Table 1 — Seismic Design Values PLE Site Class D "Stiff Soil' Ss 0. 91 (g) S1 0.10 (g) Fa 1.567 F .39 SMs 0.456 Smi 0. 44 Sys 0.304 Sol 0.163 4. SOILS EXPLORATION " Exploration and Sampling Procedures Field exploration conducted to determine engineering characteristics of subsurface materials included a reconnaissance of the project site and investigation by test pit. Test pit sites were located in the field by means of a Global Positioning System (GPS) device and are reportedly accurate to within fifteen feet. Upon completion of investigation, each test pit was backfilled with loose excavated materials. Re -excavation and compaction of these test pit areas are required prior to construction of overlying structures. In addition, samples were obtained from representative soil strata encountered. Samples obtained have been visually classified in the field by professional staff, identified according to test pit number and depth, placed in sealed containers, and transported to our laboratory for additional testing. Subsurface materials have been described in detail on logs provided in the Appendix. Results of field and laboratory tests are also presented in the Appendix. Atlas recommends that these logs not be used to estimate fill material quantities. aboratory Testing Program Along with our field investigation, a supplemental laboratory testing program was conducted to determine additional pertinent engineering characteristics of subsurface materials necessary in an analysis of anticipated behavior of the proposed structures. Laboratory tests were conducted in accordance with current applicable American Society for Testing and Materials (ASTM) specifications, and results of these tests are to be found in the Appendix. The laboratory testing program for this report included: Atterberg Limits Testing — ASTM D4318 and Grain Size Analysis — ASTM C117/C136. Atlas No. B 01400g Page14 Copyright © 0 0 Atlas Technical Consultants CUEIDR IAy APPROVED DATE 03/02/22 FIEF NUMBER: FP- 21- 11 lil and Sediment Profile TT2"ile below represents a generalized interpretation for the project site. Note that on site soils strata, encountered between test pit locations, may vary from the individual soil profiles presented in the logs, which can be found in the Appendix. The materials encountered during exploration were quite typical for the geologic area mapped as Gravel of Sunrise Terrace. Lean clays encountered at ground surface across the site. These fine-grained soils were brown to light brown, dry to slightly moist, and ranged from medium stiff to very stiff. Below these surficial materials, various silt and sand mixtures were encountered. These soils were noted to be gray to tan to light brown, dry to slightly moist, very stiff to hard/loose to dense, and contained fine to coarse -grained sand. Fine to coarse gravel was also noted within these soils in test pit 3. Weak to moderate calcium carbonate cementation was noted throughout this soil horizon. At depth, poorly graded gravel with sand sediments were exposed. Poorly graded gravels were light brown to brown to gray, dry to slightly moist, and dense to very dense. Fine to coarse - grained sand, fine to coarse gravel, and 1 -inch minus cobbles were noted throughout. Weak to strong calcium carbonate cementation was noted generally within the upper few feet of these gravels. Competency of test pit sidewalls varied little across the site. In general, fine grained soils remained stable while more granular sediments readily sloughed. However, moisture contents will also affect wall competency with saturated soils having a tendency to readily slough when under load and unsupported. 4.4 Volatile Organic Scan No environmental concerns were identified prior to commencement of the investigation. Therefore, soils obtained during on -site activities were not assessed for volatile organic compounds by portable photoionization detector. Samples obtained during our exploration activities exhibited no odors or discoloration typically associated with this type of contamination. No groundwater was encountered. 5. SITE HYDROLOGY Existing surface drainage conditions are defined in the General Site Characteristics section. Information provided in this section is limited to observations made at the time of the investigation. Either regional or local ordinances may require information beyond the scope of this report. 5.1 Groundwater During this field investigation, groundwater was not encountered in test pits advanced to a maximum depth of 16. feet bgs. Soil moistures in the test pits were generally dry to slightly moist throughout. In the vicinity of the project site, groundwater levels are controlled in large part by residential and commercial irrigation activity and leakage from nearby canals. Maximum groundwater elevations likely occur during the later portion of the irrigation season. Atlas No. B 01400g Page 15 Copyright © 0 0 Atlas Technical Consultants 1E IDIAN - APPROVED DATE: 03/02/22 previously performed 7 geotechnical investigations within 0.50 mile of the project site. FILE NUMBER: F-D21-17 lion from these investigations has been provided in the table below. Table 2 - Groundwater Data r- Date 60M July 006 Approximate . from Site (mile) 0.3 from Site -- West Depth'Direction (feet .. Not Encountered to 13.7 August 004 0.3 West Not Encountered to 15.0 October 005 0.4 Southwest Not Encountered to 16.5 June 017 0. 0 Southwest Not Encountered to 15. June 006 0.45 South Not Encountered to 1 .4 February 017 0. 0 East Not Encountered to 15.7 December 017 0.45 East 17.5 to 17.9 Based on evidence of this investigation and background knowledge of the area, Atlas estimates groundwater depths to remain greater than approximately 15 feet bgs throughout the year. ,oil infiltration Kates Soil permeability, which is a measure of the ability of a soil to transmit a fluid, was not tested in the field. Given the absence of direct measurements, for this report an estimation of infiltration is presented using generally recognized values for each soil type and gradation. Of soils comprising the generalized soil profile for this study, lean clay soils generally offer little permeability, with typical hydraulic infiltration rates of less than inches per hour. Sandy silt soils will commonly exhibit infiltration rates from to 4 inches per hour and silty sand sediments usually display rates of 4 to 8 inches per hour. Poorly graded gravel sediments typically exhibit infiltration values in excess of 1 inches per hour. Varying degrees of calcium carbonate cementation were noted within manv of the soils encountered. If Dresent. cementation may reduce these values to near zero It is recommended that infiltration facilities constructed on the site be extended into native non - cemented poorly graded gravel with sand sediments. Excavation depths ranging from 8.3 to greater than 1 .4 feet bgs should be anticipated to expose these poorly graded gravel with sand sediments. Because of the high soil permeability, ASTM C33 filter sand, or equivalent, should be incorporated into design of infiltration facilities. An infiltration rate of 8 inches per hour should be used in design. Actual infiltration rates should be confirmed at the time of construction. FOUNDATION AND SLAB DISCUSSION AND RECOMMENDATIONS Various foundation types have been considered for support of the proposed structures. Two requirements must be met in the design of foundations. First, the applied bearing stress must be less than the ultimate bearing capacity of foundation soils to maintain stability. Second, total and differential settlement must not exceed an amount that will produce an adverse behavior of the superstructure. Atlas No. B 01400g Page16 Copyright © 0 0 Atlas Technical Consultants IDS IAN;- APPROVED DATE: 03/02/22 FILE NUMBER FP- 21-1, a settlement is usually exceeded before bearing capacity considerations become t; thus, allowable bearing pressure is normally controlled by settlement considerations. Considering subsurface conditions and the proposed construction, it is recommended that the structures be founded upon conventional spread footings and continuous wall footings. Total settlements should not exceed 1 inch if the following design and construction recommendations are observed. 6.1 Foundation Design Recommendations Based on data obtained from the site and test results from various laboratory tests performed, Atlas recommends the following guidelines for the net allowable soil bearing capacity: Table 3 - Soil Bearing Capacity Footing Depth Ab I rZI Ill 551 —net Allowable boil Subgrade CompactionCapacity Footings must bear on competent, undisturbed, 1,500lbs/ft native lean clay soils or compacted structural fill. Not Required for Native Existing organics and disturbed zone (plow depths) Soil A /3 increase is allowable must be completely removed from below foundation for short-term loading, elements.' An excavation depth of approximately 951% for Structural Fill which is defined by 1.0 foot bgs should be anticipated to expose proper seismic events or bearing soils. designed wind speeds. Footings must bear on competent, undisturbed, native cemented sandy silt or silty sand soils or Not Required for Native compacted structural fill. Existing lean clay soils Soil must be completely removed from below foundation 500 Ibs/ft elements.' Excavation depths ranging from roughly 95% for Structural Fill 1.3 to .1 feet bgs should be anticipated to expose proper bearing soils. 'It will be required for Atlas personnel to verify the bearing soil suitability for each structure at the time of construction. 'Depending on the time of year construction takes place, the subgrade soils may be unstable because of high moisture contents. If unstable conditions are encountered, over -excavation and replacement with granular structural fill and/or use of geotextiles may be required. The following sliding frictional coefficient values should be used: 1) 0.35 for footings bearing on native lean clay or sandy silt/silty sand soils and ) 0.45 for footings bearing on granular structural fill. A passive lateral earth pressure of 349 pounds per square foot per foot (psf/ft) should be used for sandy silt/silty sand soils. For compacted sandy gravel fill, a passive lateral earth pressure of 496 psf/ft should be used. Footings should be proportioned to meet either the stated soil bearing capacity or the 015 IBC minimum requirements. Total settlement should be limited to approximately 1 inch, and differential settlement should be limited to approximately '/2 inch. Objectionable soil types encountered at the bottom of footing excavations should be removed and replaced with structural fill. Atlas No. B 01400g Page l7 Copyright © 0 0 Atlas Technical Consultants CUEIDR IAy APPROVED DATE 03/02/22 ely loose or soft areas that are encountered in the footings subgrade will require over - FILE NUMBER: FP-zozvoon Ln and backfilling with structural fill. To minimize the effects of slight differential movement that may occur because of variations in the character of supporting soils and seasonal moisture content, Atlas recommends continuous footings be suitably reinforced to make them as rigid as possible. For frost protection, the bottom of external footings should be 30 inches below finished grade. 6.2 Foundation Drain Recommendations Considering the presence of shallow cemented soils across the site, Atlas recommends that foundation drains be installed. The drains should be placed at the footing elevation, sloped at least percent, and be directed to suitable discharge points at least 10 feet away from the structures. Discharge points should be protected to prevent erosion. 6.3 Floor Slab -on -Grade Plow zones with organic materials were encountered in portions of the site. Atlas recommends that the organic materials be removed. If plow zones remain after organic materials have been removed, the exposed subgrade must be compacted to at least 95 percent of the maximum dry density as determined by ASTM D1557. Atlas personnel must be present during excavation to identify these materials. Organic, loose, or obviously compressive materials must be removed prior to placement of concrete floors or floor -supporting fill. In addition, the remaining subgrade should be treated in accordance with guidelines presented in the Earthwork section. Areas of excessive yielding should be excavated and backfilled with structural fill. Fill used to increase the elevation of the floor slab should meet requirements detailed in the Structural Fill section. Fill materials must be compacted to a minimum 95 percent of the maximum dry density as determined by ASTM D1557. A free -draining granular mat should be provided below slabs -on -grade to provide drainage and a uniform and stable bearing surface. This should be a minimum of 4 inches in thickness and properly compacted. The mat should consist of a sand and gravel mixture, complying with Idaho Standards for Public Works Construction (ISPWC) specifications for 3/4-inch (Type 1) crushed aggregate. The granular mat should be compacted to no less than 95 percent of the maximum dry density as determined by ASTM D1557. A moisture -retarder should be placed beneath floor slabs to minimize potential ground moisture effects on moisture -sensitive floor coverings. The moisture -retarder should be at least 15-mil in thickness and have a permeance of less than 0.01 US perms as determined by ASTM E96. Placement of the moisture -retarder will require special consideration with regard to effects on the slab -on -grade and should adhere to recommendations outlined in the ACI 30 .1 R and ASTM E1745 publications. Upon request, Atlas can provide further consultation regarding installation. Atlas No. B 01400g Page18 Copyright © 0 0 Atlas Technical Consultants 1 E IDS IAN,_— APPROVED DATE: 03/02/22 FILE NUMBER: FP-2021-1111 EMENT DISCUSSION AND RECOMMENDATIONS ATla�s made assumptions for traffic loading variables based on the character of the proposed construction. The Client shall review and understand these assumptions to make sure they reflect intended use and loading of pavements both now and in the future. Based on experience with soils in the region, a subgrade California Bearing Ratio (CBR) value of 4 has been assumed for near -surface clay soils on site. The following are minimum thickness requirements for assured pavement function. Depending on site conditions, additional work, e.g. soil preparation, may be required to support construction equipment. These have been listed within the Soft Subgrade Soils section. 7.1 Flexible Pavement Sections The American Association of State Highway and Transportation Officials (AASHTO) design method has been used to calculate the following pavement sections. Calculation sheets provided in the Appendix indicate the soils constant, traffic loading, traffic projections, and material constants used to calculate the pavement sections. Atlas recommends that materials used in the construction of asphaltic concrete pavements meet requirements of the ISPWC Standard Specification for Highway Construction. Construction of the pavement section should be in accordance with these specifications and should adhere to guidelines recommended in the section on Construction Considerations. Table 4 — AASHTO Flexible Pavement Specifications JrDriveways and Parking Driveways and Park! Pavement Section Component L Light Duty ModerateFW Asphaltic Concrete .5 Inches 3.0 Inches Crushed Aggregate Base 4.0 Inches 4.0 Inches Structural Subbase 10.0 Inches 1 .0 Inches Compacted Subgrade See Pavement Subgrade See Pavement Subgrade Preparation Section Preparation Section 'It will be required for Atlas personnel to verify subgrade competency at the time of construction. Asphaltic Concrete: Asphalt mix design shall meet the requirements of ISPWC, Section 810 Class III plant mix. Materials shall be placed in accordance with ISPWC Standard Specifications for Highway Construction. Aggregate Base: Material complying with ISPWC Standards for Crushed Aggregate Materials. Structural Subbase: Granular structural fill material complying with the requirements detailed in the Structural Fill section of this report except that the maximum material diameter is no more than /3 the component thickness. Gradation and suitability requirements shall be per ISPWC Section 801, Table 1. Atlas No. B 01400g Page19 Copyright © 0 0 Atlas Technical Consultants 1 E IDS IAN,_— �J rvemenit APPROVED DATE: 03/02/22_ FILE NUMBER:F-D2111 Subgrade Preparation Plow zones with organic materials were encountered across the site. Atlas recommends that the organic materials be removed. If plow zones remain after organic materials have been removed, the exposed subgrade must be compacted to at least 95 percent of the maximum dry density as determined by ASTM D698. Atlas personnel must be present during excavation to identify these materials. 7.3 Common Pavement Section Construction Issues The subgrade upon which above pavement sections are to be constructed must be properly stripped, inspected, and proof -rolled. Proof rolling of subgrade soils should be accomplished using a heavy rubber -tired, fully loaded, tandem -axle dump truck or equivalent. Verification of subgrade competence by Atlas personnel at the time of construction is required. Fill materials on the site must demonstrate the indicated compaction prior to placing material in support of the pavement section. Atlas anticipated that pavement areas will be subjected to moderate traffic. Subgrade clayey and silty soils near and above optimum moisture contents may pump during compaction. Pumping or soft areas must be removed and replaced with structural fill. Fill material and aggregates, in support of the pavement section must be compacted to no less than 95 percent of the maximum dry density as determined by ASTM D698 for flexible pavements and by ASTM D1557 for rigid pavements. If a material placed as a pavement section component cannot be tested by usual compaction testing methods, then compaction of that material must be approved by observed proof rolling. Minor deflections from proof rolling for flexible pavements are allowable. Deflections from proof rolling of rigid pavement support courses should not be visually detectable. Atlas recommends that rigid concrete pavement be provided for heavy garbage receptacles. This will eliminate damage caused by the considerable loading transferred through the small steel wheels onto asphaltic concrete. Rigid concrete pavement should consist of Portland Cement Concrete Pavement (PCCP) generally adhering to ITD specifications for Urban Concrete. PCCP should be 6 inches thick on a 4-inch drainage fill course (see Floor Slab -on -Grade section), and should be reinforced with welded wire fabric. Control joints must be on 1 -foot centers or less. 8. CONSTRUCTION CONSIDERATIONS Recommendations in this report are based upon structural elements of the project being founded on competent, native lean clay, sandy silt, or silty sand soils, or compacted structural fill. Structural areas should be stripped to an elevation that exposes these soil types. 8.1 Earthwork Excessively organic soils, deleterious materials, or disturbed soils generally undergo high volume changes when subjected to loads, which is detrimental to subgrade behavior in the area of pavements, floor slabs, structural fills, and foundations. It is recommended that organic or disturbed soils, if encountered, be removed to depths of 1 foot (minimum), and wasted or stockpiled for later use. Atlas No. B 01400g Page110 Copyright © 0 0 Atlas Technical Consultants �E IDR IAy Lg-- APPROVED DATE 03/02/22 FIEF NUMBER: FP-2o21-11 depths should be adjusted in the field to assure that the entire root zone or disturbed w depths) or topsoil are removed prior to placement and compaction of structural fill materials. Exact removal depths should be determined during grading operations by Atlas personnel, and should be based upon subgrade soil type, composition, and firmness or soil stability. If underground storage tanks, underground utilities, wells, or septic systems are discovered during construction activities, they must be decommissioned then removed or abandoned in accordance with governing Federal, State, and local agencies. Excavations developed as the result of such removal must be backfilled with structural fill materials as defined in the Structural Fill section. Atlas should oversee subgrade conditions (i.e., moisture content) as well as placement and compaction of new fill (if required) after native soils are excavated to design grade. Recommendations for structural fill presented in this report can be used to minimize volume changes and differential settlements that are detrimental to the behavior of footings, pavements, and floor slabs. Sufficient density tests should be performed to properly monitor compaction. For structural fill beneath building structures, one in -place density test per lift for every 5,000 square feet is recommended. In parking and driveway areas, this can be decreased to one test per lift for every 10,000 square feet. 8.2 Dry Weather If construction is to be conducted during dry seasonal conditions, many problems associated with soft soils may be avoided. However, some rutting of subgrade soils may be induced by shallow groundwater conditions related to springtime runoff or irrigation activities during late summer through early fall. Solutions to problems associated with soft subgrade soils are outlined in the Soft Subgrade Soils section. Problems may also arise because of lack of moisture in native and fill soils at time of placement. This will require the addition of water to achieve near -optimum moisture levels. Low -cohesion soils exposed in excavations may become friable, increasing chances of sloughing or caving. Measures to control excessive dust should be considered as part of the overall health and safety management plan. 8.3 Wet Weather If construction is to be conducted during wet seasonal conditions (commonly from mid -November through May), problems associated with soft soils must be considered as part of the construction plan. During this time of year, fine-grained soils such as silts and clays will become unstable with increased moisture content, and eventually deform or rut. Additionally, constant low temperatures reduce the possibility of drying soils to near optimum conditions. 8.4 Soft Subgrade Soils Shallow fine-grained subgrade soils that are high in moisture content should be expected to pump and rut under construction traffic. During periods of wet weather, construction may become very difficult if not impossible. The following recommendations and options have been included for dealing with soft subgrade conditions: Atlas No. B 01400g Page111 Copyright © 0 0 Atlas Technical Consultants CUEIDR IAy APPROVED DATE 03/02/22 FILE NUMBER: FP- 21- 11 rack -mounted vehicles should be used to strip the subgrade of root matter and other leleterious debris. Heavy rubber -tired equipment should be prohibited from operating directly on the native subgrade and areas in which structural fill materials have been placed. Construction traffic should be restricted to designated roadways that do not cross, or cross on a limited basis, proposed roadway or parking areas. • Soft areas can be over -excavated and replaced with granular structural fill. • Construction roadways on soft subgrade soils should consist of a minimum -foot thickness of large cobbles of 4 to 6 inches in diameter with sufficient sand and fines to fill voids. Construction entrances should consist of a 6-inch thickness of clean, -inch minimum, angular drain -rock and must be a minimum of 10 feet wide and 30 to 50 feet long. During the construction process, top dressing of the entrance may be required for maintenance. • Scarification and aeration of subgrade soils can be employed to reduce the moisture content of wet subgrade soils. After stripping is complete, the exposed subgrade should be ripped or disked to a depth of 1'/2 feet and allowed to air dry for to 4 weeks. Further disking should be performed on a weekly basis to aid the aeration process. • Alternative soil stabilization methods include use of geotextiles, lime, and cement stabilization. Atlas is available to provide recommendations and guidelines at your request. 8.5 Frozen Subgrade Soils Prior to placement of structural fill materials or foundation elements, frozen subgrade soils must either be allowed to thaw or be stripped to depths that expose non -frozen soils and wasted or stockpiled for later use. Stockpiled materials must be allowed to thaw and return to near -optimal conditions prior to use as structural fill. The onsite, shallow clayey and silty soils are susceptible to frost heave during freezing temperatures. For exterior flatwork and other structural elements, adequate drainage away from subgrades is critical. Compaction and use of structural fill will also help to mitigate the potential for frost heave. Complete removal of frost susceptible soils for the full frost depth, followed by replacement with a non -frost susceptible structural fill, can also be used to mitigate the potential for frost heave. Atlas is available to provide further guidance/assistance upon request. 8.6 Structural Fill Soils recommended for use as structural fill are those classified as GW, GP, SW, and SP in accordance with the Unified Soil Classification System (USCS) (ASTM D 487). Use of silty soils (USCS designation of GM, SM, and ML) as structural fill may be acceptable. However, use of silty soils (GM, SM, and ML) as structural fill below footings is prohibited. These materials require very high moisture contents for compaction and require a long time to dry out if natural moisture contents are too high and may also be susceptible to frost heave under certain conditions. Therefore, these materials can be quite difficult to work with as moisture content, lift thickness, and compactive effort becomes difficult to control. Atlas No. B 01400g Page11 Copyright © 0 0 Atlas Technical Consultants 1E IDIAN - APPROVED DATE: 03/02/22 FILE NUMBER: FP-2021-0011 materials already placed. Following placement, silty soils must be protected from degradation resulting from construction traffic or subsequent construction. Recommended granular structural fill materials, those classified as GW, GP, SW, and SP, should consist of a 6-inch minus select, clean, granular soil with no more than 50 percent oversize (greater than 3/4-inch) material and no more than 1 percent fines (passing No. 00 sieve). These fill materials should be placed in layers not to exceed 1 inches in loose thickness. Prior to placement of structural fill materials, surfaces must be prepared as outlined in the Construction Considerations section. Structural fill material should be moisture -conditioned to achieve optimum moisture content prior to compaction. For structural fill below footings, areas of compacted backfill must extend outside the perimeter of the footings for a distance equal to the thickness of fill between the bottom of foundation and underlying soils, or 5 feet, whichever is less. All fill materials must be monitored during placement and tested to confirm compaction requirements, outlined below, have been achieved. Each layer of structural fill must be compacted, as outlined below: Below Structures and Rigid Pavements: A minimum of 95 percent of the maximum dry density as determined by ASTM D1557. Below Flexible Pavements: A minimum of 9 percent of the maximum dry density as determined by ASTM D1557 or 95 percent of the maximum dry density as determined by ASTM D698. The ASTM D1557 test method must be used for samples containing up to 40 percent oversize (greater than 3/4-inch) particles. If material contains more than 40 percent but less than 50 percent oversize particles, compaction of fill must be confirmed by proof rolling each lift with a 10-ton vibratory roller (or equivalent) until the maximum density has been achieved. Density testing must be performed after each proof rolling pass until the in -place density test results indicate a drop (or no increase) in the dry density, defined as maximum density or "break over" point. The number of required passes should be used as the requirements on the remainder of fill placement. Material should contain sufficient fines to fill void spaces, and must not contain more than 50 percent oversize particles. 8.7 Backfill of Walls Backfill materials must conform to the requirements of structural fill, as defined in this report. For wall heights greater than .5 feet, the maximum material size should not exceed 4 inches in diameter. Placing oversized material against rigid surfaces interferes with proper compaction, and can induce excessive point loads on walls. Backfill shall not commence until the wall has gained sufficient strength to resist placement and compaction forces. Further, retaining walls above .5 feet in height shall be backfilled in a manner that will limit the potential for damage from compaction methods and/or equipment. Atlas No. B 01400g Page113 Copyright © 0 0 Atlas Technical Consultants CUEIDR IAy APPROVED DATE 03/02/22 mmended that only small hand -operated compaction equipment be used for compaction FIEF NUMBER: FP-21-oo11 III within a horizontal distance equal to the height of the wall, measured from the back face of the wall. Backfill should be compacted in accordance with the specifications for structural fill, except in those areas where it is determined that future settlement is not a concern, such as planter areas. In nonstructural areas, backfill must be compacted to a firm and unyielding condition. 8.8 Excavations Shallow excavations that do not exceed 4 feet in depth may be constructed with side slopes approaching vertical. Below this depth, it is recommended that slopes be constructed in accordance with Occupational Safety and Health Administration (OSHA) regulations, Section 19 6, Subpart P. Based on these regulations, on -site soils are classified as type "C" soil, and as such, excavations within these soils should be constructed at a maximum slope of 1'/2 feet horizontal to 1 foot vertical (11/2:1) for excavations up to 0 feet in height. Excavations in excess of 0 feet will require additional analysis. Note that these slope angles are considered stable for short-term conditions only, and will not be stable for long-term conditions. During the subsurface exploration, test pit sidewalls generally exhibited little indication of collapse; however, sloughing of plow zone materials and native granular sediments from test pit sidewalls was observed. For deep excavations, native granular sediments cannot be expected to remain in position. These materials are prone to failure and may collapse, thereby undermining upper soil layers. This is especially true when excavations approach depths near the water table. Care must be taken to ensure that excavations are properly backfilled in accordance with procedures outlined in this report. 8.9 Groundwater Control It may be possible to discharge dewatering effluent to remote portions of the site, to a sump, or to a pit. This will essentially recycle effluent, thus eliminating the need to enter into agreements with local drainage authorities. Should the scope of the proposed project change, Atlas should be contacted to provide more detailed groundwater control measures. Special precautions may be required for control of surface runoff and subsurface seepage. It is recommended that runoff be directed away from open excavations. Silty and clayey soils may become soft and pump if subjected to excessive traffic during time of surface runoff. Ponded water in construction areas should be drained through methods such as trenching, sloping, crowning grades, nightly smooth drum rolling, or installing a French drain system. Additionally, temporary or permanent driveway sections should be constructed if extended wet weather is forecasted. Atlas No. B 01400g Page114 Copyright © 0 0 Atlas Technical Consultants �E IDR IAy L APPROVED DATE 03/02/22 FILE NUMBER: FP-2021-0011 NERAL COMMENTS a�cf—on the subsurface conditions encountered during this investigation and available information regarding the proposed development, the site is adequate for the planned construction. When plans and specifications are complete, and if significant changes are made in the character or location of the proposed structure, consultation with Atlas must be arranged as supplementary recommendations may be required. Suitability of subgrade soils and compaction of structural fill materials must be verified by Atlas personnel prior to placement of structural elements. Additionally, monitoring and testing should be performed to verify that suitable materials are used for structural fill and that proper placement and compaction techniques are utilized. Atlas No. B 01400g Page115 Copyright © 0 0 Atlas Technical Consultants CUEIDR IAy APPROVED DATE 03/02/22 FILE NUMBER: FP-21-11 IFERENCES me�ncan Association of State Highway and Transportation Officials (AASHTO) (1993). AASHTO Guide for Design of Pavement Structures 1993. Washington D.C.: AASHTO. American Concrete Institute (ACI) ( 015). Guide for Concrete Floor and Slab Construction: ACI 30 .1 R. Farmington Hills, MI: ACI. American Society of Civil Engineers (ASCE) ( 013). Minimum Design Loads for Buildings and Other Structures: ASCE/SE I 7-10. Reston, VA: ASCE. American Society for Testing and Materials (ASTM) ( 017). Standard Test Method for Materials Finer than 75-um (No. 00) Sieve in Mineral Aggregates by Washing: ASTM C117. West Conshohocken, PA: ASTM. American Society for Testing and Materials (ASTM) ( 014). Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates: ASTM C136. West Conshohocken, PA: ASTM. American Society for Testing and Materials (ASTM) ( 01 ). Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Standard Effort: ASTM D698. West Conshohocken, PA: ASTM. American Society for Testing and Materials (ASTM) ( 01 ). Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort: ASTM D1557. West Conshohocken, PA: ASTM. American Society for Testing and Materials (ASTM) ( 017). Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System): ASTM D 487. West Conshohocken, PA: ASTM. American Society for Testing and Materials (ASTM) ( 017). Standard Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils: ASTM D4318. West Conshohocken, PA: ASTM. American Society for Testing and Materials (ASTM) ( 011). Standard Specification for Plastic Water Vapor Retarders Used in Contact with Soil or Granular Fill Under Concrete Slabs: ASTM E1745. West Conshohocken, PA: ASTM. Desert Research Institute. Western Regional Climate Center. [Online] Available: <http://www.wrcc.dri.edu/> ( 0 0). International Building Code Council ( 015). International Building Code, 015. Country Club Hills, IL: Author. Local Highway Technical Assistance Council (LHTAC) ( 017). Idaho Standards for Public Works Construction, 017. Boise, ID: Author. Othberg, K. L. and Stanford, L. A., Idaho Geologic Society (1993). Geologic Map of the Boise Valley and Adjoining Area, Western Snake River Plain, Idaho. (scale 1:100,000). Boise, ID: Joslyn and Morris. U.S. Department of Labor, Occupational Safety and Health Administration. CFR 9, Part 19 6, Subpart P: Safety and Health Regulations for Construction, Excavations (1986). [Online] Available: <www.osha.gov> ( 0 0). U.S. Geological Survey ( 0 0). National Water Information System: Web Interface. [Online] Available: <http://waterdata.usgs.gov/nwis> ( 0 0). U.S. Geological Survey. ( 009). Seismicity of Idaho 1990- 006. [Online] Available: <http://earthquake.usgs.gov/earthquakes/states/Idaho/seismicity.php> ( 0 0). U.S. Geological Survey. ( 011). U.S. Seismic Design Maps: Web Interface. [Online] Available: <https://earthquake.usgs.gov/designmaps/us/application.php> ( 0 0). Atlas No. B 01400g Page116 Copyright © 0 0 Atlas Technical Consultants CUEIDR IAy C APPROVED DATE 03/02/22 FILE NUMBER: FP-2,21-11 [Appendix I WARRANTY AND LIMITING CONDITIONS Atlas warrants that findings and conclusions contained herein have been formulated in accordance with generally accepted professional engineering practice in the fields of foundation engineering, soil mechanics, and engineering geology only for the site and project described in this report. These engineering methods have been developed to provide the client with information regarding apparent or potential engineering conditions relating to the site within the scope cited above and are necessarily limited to conditions observed at the time of the site visit and research. Field observations and research reported herein are considered sufficient in detail and scope to form a reasonable basis for the purposes cited above. Exclusive Use This report was prepared for exclusive use of the property owner(s), at the time of the report, and their retained design consultants ("Client"). Conclusions and recommendations presented in this report are based on the agreed -upon scope of work outlined in this report together with the Contract for Professional Services between the Client and Materials Testing and Inspection ("Consultant"). Use or misuse of this report, or reliance upon findings hereof, by parties other than the Client is at their own risk. Neither Client nor Consultant make representation of warranty to such other parties as to accuracy or completeness of this report or suitability of its use by such other parties for purposes whatsoever, known or unknown, to Client or Consultant. Neither Client nor Consultant shall have liability to indemnify or hold harmless third parties for losses incurred by actual or purported use or misuse of this report. No other warranties are implied or expressed. Report Recommendations are Limited and Subject to Misinterpretation There is a distinct possibility that conditions may exist that could not be identified within the scope of the investigation or that were not apparent during our site investigation. Findings of this report are limited to data collected from noted explorations advanced and do not account for unidentified fill zones, unsuitable soil types or conditions, and variability in soil moisture and groundwater conditions. To avoid possible misinterpretations of findings, conclusions, and implications of this report, Atlas should be retained to explain the report contents to other design professionals as well as construction professionals. Since actual subsurface conditions on the site can only be verified by earthwork, note that construction recommendations are based on general assumptions from selective observations and selective field exploratory sampling. Upon commencement of construction, such conditions may be identified that require corrective actions, and these required corrective actions may impact the project budget. Therefore, construction recommendations in this report should be considered preliminary, and Atlas should be retained to observe actual subsurface conditions during earthwork construction activities to provide additional construction recommendations as needed. Since geotechnical reports are subject to misinterpretation, do not separate the soil logs from the report. Rather, provide a copy of, or authorize for their use, the complete report to other design Atlas No. B 01400g Page117 Copyright © 0 0 Atlas Technical Consultants �E IDR IAy Ld-- APPROVED DATE 03/02/22 FILE NUMBER: FP- 21- 11 nals or contractors. Locations of exploratory sites referenced within this report should lidered approximate locations only. For more accurate locations, services of a professional land surveyor are recommended. This report is also limited to information available at the time it was prepared. In the event additional information is provided to Atlas following publication of our report, it will be forwarded to the client for evaluation in the form received. Environmental Concerns Comments in this report concerning either onsite conditions or observations, including soil appearances and odors, are provided as general information. These comments are not intended to describe, quantify, or evaluate environmental concerns or situations. Since personnel, skills, procedures, standards, and equipment differ, a geotechnical investigation report is not intended to substitute for a geoenviron mental investigation or a Phase II/III Environmental Site Assessment. If environmental services are needed, Atlas can provide, via a separate contract, those personnel who are trained to investigate and delineate soil and water contamination. Atlas No. B 01400g Page118 Copyright © 0 0 Atlas Technical Consultants v E_ 80 00 dca APPROVED o Of E A LL DATE: 03/02/22 'a m a)o o U) N p N V : I,ENUMBER: Fa-zDVDD51 m : 0 o X CD o O m rn Z .X Z C 4WD o W O .� O W a3 N o c � m Q w a > Z J Q J a) 75 CD 21 co O U a N 2 M O o N m Z N ro N 5_CL4ERD-_R D Oa 31tlQb3A0"I3 N da �7bvlda 0_9 C41�( .f Lu O � v O Lu 0 / W W N-EAGLE_RD fl S_EA-GLE_RD SzEA.GL"E_RDCL mDo Ln Ln Sw.� OA �� w J Z ce W h In FL-17M a d o c tj Z _ Y 5 o UJ _,,� E_1S_T_5T w rw j S 1S ISi 49 u.i LLi # {7 1� �35 mi 13 01 fF 1 <1 f �. - If �1• W-TwW.m.0 1 E IDS IAN,_- APPROVED L Liendix IV GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log #: TP-1 Latitude: 43.59 8894 Date Advanced: October 5, 0 0 Longitude:-116.3607975 Excavated by: Turn of the Century Homes Depth to Water Table: Not Encountered Logged by: Weston Jorgenson, GIT Total Depth: 16. feet bgs D7ept 7bgs)bgs) eld Description and USCS Soil and Sample Sample Depth Qp i Lab Lesj1D Lean Clay (CL): Brown, dry to slightly moist, 0.0-1.6 medium stiff to very stiff. 1.0-4.0 --Organics noted to 0. foot bgs. --Plow zone noted to 1.0 foot bgs. Sandy Silt (ML): Gray, dry to slightly moist, very stiff to hard, with fine to medium -grained 1.6-6.1 sand. 3.5-4.5 --Weak calcium carbonate cementation noted throughout. Silty Sand (SM): Light brown, slightly moist, dense, with fine to coarse -grained sand. 6.1-8.7 --Weak calcium carbonate cementation noted throughout. --Fine to coarse gravel noted below 8.0 feet. Poorly Graded Gravel with Sand (GP): Gray, 8.7-16. slightly moist, dense, with fine to coarse - grained sand, fine to coarse gravel, and 8- inch-minus cobbles. Notes: See Site Map for test pit location. Atlas No. B 01400g Page 1 1 Copyright © 0 0 Atlas Technical Consultants 1 E IDS IAN,_— APPROVED DATE: 03/02/22 fIIENUMBER: F-o2,-11 j GEOTECHNICAL INVESTIGATION TEST PIT LOG Test it Log #: TP- Latitude: 43.5933110 Date Advanced: October 5, 0 0 Longitude:-116.3617500 Excavated by: Turn of the Century Homes Depth to Water Table: Not Encountered Logged by: Weston Jorgenson, GIT Total Depth: 11.9 feet bgs Depth Field Description and USCS Soil and �&77ple Depth Qp Lab .. bgs) Test ID Lean Clay (CL): Brown, dry to slightly moist, 0.0-1.4 medium stiff to very stiff. 1.0-3.0 --Organics noted to 0. foot bgs. --Plow zone noted to 1.0 foot bgs. Silty Sand (SM): Gray, slightly moist, dense, 1.4-7.3 with fine to medium -grained sand. --Weak to moderate calcium carbonate cementation noted throughout. Poorly Graded Gravel with Sand (GP): Light brown to gray, slightly moist, dense to very 7.3-11.9 dense, with fine to coarse -grained sand, fine to coarse gravel, and 10-inch-minus cobbles. --Moderate calcium carbonate cementation noted from 7.3 to 10.8 feet bgs. Notes: See Site Map for test pit location. Atlas No. B 01400g Page Copyright © 0 0 Atlas Technical Consultants 1 E IDS IAN,_— APPROVED DATE: 03/02/22 fIIENUMBER: F-o2,-11 j GEOTECHNICAL INVESTIGATION TEST PIT LOG Test it Log #: TP-3 Latitude: 43.59 6134 Date Advanced: October 5, 0 0 Longitude:-116.3618 7 Excavated by: Turn of the Century Homes Depth to Water Table: Not Encountered Logged by: Weston Jorgenson, GIT Total Depth: 1 .5 feet bgs Depth Field Description and USCS Soil and �&77ple Depth Qp Lab .. bgs) Test ID Lean Clay (CL): Brown, dry to slightly moist, 0.0-1.3 medium stiff to very stiff. GS 0.5-1.0 1.0- A --Organics noted to 0. foot bgs. .0 --Plow zone noted to 1.0 foot bgs. Silty Sand with Gravel (SM): Tan to brown, dry to slightly moist, medium dense to dense, with fine to coarse -grained sand and fine to coarse 1.3-5. gravel. --Weak to moderate calcium carbonate cementation noted throughout. --Thin clay layers noted from .5 to 5.0 feet bgs. Poorly Graded Gravel with Sand (GP): Light brown to gray, dry to slightly moist, dense, with 5. -1 fine to coarse -grained sand, fine to coarse .5 gravel, and 8-inch-minus cobbles. --Weak to moderate calcium carbonate cementation noted from 5. to 8.4 feet bgs. Notes: See Site Map for test pit location. Atlas No. B 01400g Pagel 3 Copyright © 0 0 Atlas Technical Consultants 1 E IDS IAN,_— APPROVED DATE: 03/02/22 fIIENUMBER: F-o2,-11 j GEOTECHNICAL INVESTIGATION TEST PIT LOG Test it Log #: TP-4 Latitude: 43.59 304 Date Advanced: October 5, 0 0 Longitude:-116.3603033 Excavated by: Turn of the Century Homes Depth to Water Table: Not Encountered Logged by: Weston Jorgenson, GIT Total Depth: 11.0 feet bgs Depth Field Description and USCS Soil and �&77ple Depth Qp Lab .. bgs) Test ID Lean Clay (CL): Brown, dry to slightly moist, 0.0-1.3 medium stiff to very stiff. 1.0- --Organics noted to 0.3 foot bgs. .0 --Plow zone noted to 1.0 foot bgs. Silty Sand with Gravel (SM): Light brown to tan, dry to slightly moist, loose to medium 1.3-6.3 dense, with fine to medium -grained sand. --Weak to moderate calcium carbonate cementation noted from 3. to 6.3 feet bgs. Poorly Graded Gravel with Sand (GP): Light brown to gray, dry to slightly moist, dense to very dense, with fine to coarse -grained sand, 6.3-11.0 fine to coarse gravel, and 8-inch-minus cobbles. --Weak to moderate calcium carbonate cementation noted from 6.3 to 8.3 feet bgs. Notes: See Site Map for test pit location. Atlas No. B 01400g Pagel 4 Copyright © 0 0 Atlas Technical Consultants 1 E IDS IAN,_— APPROVED DATE: 03/02/22 fIIENUMBER: F-o2,-11 j GEOTECHNICAL INVESTIGATION TEST PIT LOG Test it Log #: TP-5 Latitude: 43.5913198 Date Advanced: October 5, 0 0 Longitude:-116.3599593 Excavated by: Turn of the Century Homes Depth to Water Table: Not Encountered Logged by: Weston Jorgenson, GIT Total Depth: 10. feet bgs Depth Field Description and USCS Soil and �&77ple Depth Qp Lab .. bgs) Test ID Lean Clay (CL): Brown, dry to slightly moist, 0.0-1.5 stiff to very stiff. 1.5-3.0 --Organics noted to 0. foot bgs. --Plow zone noted to 1.0 foot bgs. Silty Sand (SM): Light brown to gray, dry to slightly moist, dense, with fine to medium- 1.5-6.9 grained sand. --Weak to moderate calcium carbonate cementation noted from 1.9 to 6.9 feet bgs. Poorly Graded Gravel with Sand (GP): Light brown to gray, dry to slightly moist, dense to very dense, with fine to coarse -grained sand, 6.9-10. fine to coarse gravel, and 1 -inch-minus cobbles. --Weak calcium carbonate cementation noted from 6.9 to 9.5 feet bgs. Notes: See Site Map for test pit location. Atlas No. B 01400g Pagel 5 Copyright © 0 0 Atlas Technical Consultants 1 E IDS IAN,_— APPROVED DATE: 03/02/22 fIIENUMBER: F-o2,-11 j GEOTECHNICAL INVESTIGATION TEST PIT LOG Test it Log #: TP-6 Latitude: 43.5915580 Date Advanced: October 5, 0 0 Longitude:-116.3615800 Excavated by: Turn of the Century Homes Depth to Water Table: Not Encountered Logged by: Weston Jorgenson, GIT Total Depth: 1 .4 feet bgs Depth Field Description and USCS Soil and �&77ple Depth Qp Lab .. bgs) Test ID Lean Clay (CL): Brown, dry to slightly moist, 0.0-1.4 stiff to very stiff. 1.5- --Organics noted to 0. foot bgs. .5 --Plow zone noted to 1.0 foot bgs. Silty Sand (SM): Light brown to gray, dry to slightly moist, loose to medium dense, with 1.4-5.4 fine to medium -grained sand. --Weak to moderate calcium carbonate cementation noted from . to 5.4 feet bgs. Poorly Graded Gravel with Sand (GP): Light brown, dry to slightly moist, dense to very 5.4-1 dense, with fine to coarse -grained sand, fine .4 to coarse gravel, and 8-inch-minus cobbles. --Moderate to strong calcium carbonate cementation noted throughout. Notes: See Site Map for test pit location. Atlas No. B 01400g Pagel 6 Copyright © 0 0 Atlas Technical Consultants 1 E IDS IAN,_— APPROVED DATE: 03/02/22 fIIENUMBER: F-o2,-11 j GEOTECHNICAL INVESTIGATION TEST PIT LOG Test it Log #: TP-7 Latitude: 43.5907768 Date Advanced: October 5, 0 0 Longitude:-116.3609789 Excavated by: Turn of the Century Homes Depth to Water Table: Not Encountered Logged by: Weston Jorgenson, GIT Total Depth: 11.0 feet bgs Depth miF lield Description and USCS Soil and�&Ta`Mple Depth Qp Lab ..111L bgs) Test ID Lean Clay (CL): Light brown to brown, dry to 0.0- slightly moist, stiff to very stiff. 0- .1 --Organics noted to 0. foot bgs. .5 --Plow zone noted to 1.0 foot bgs. Silty Sand (SM): Light brown to gray, dry to slightly moist, dense, with fine to medium- .1-6.3 grained sand. --Weak calcium carbonate cementation noted throughout. Poorly Graded Gravel with Sand (GP): Brown to light brown, dry to slightly moist, dense, with 6.3-11.0 fine to coarse -grained sand, fine to coarse gravel, and 6-inch-minus cobbles. --Weak to moderate calcium carbonate cementation noted from 6.3 to 9.8 feet bgs. Notes: See Site Map for test pit location. Atlas No. B 01400g Pagel 7 Copyright © 0 0 Atlas Technical Consultants 1 E IDS IAN,_— APPROVED DATE: 03/02/22 FILE NUMBER: FP-z Iz Ds7 Appendix V GEOTECHNICAL GENERAL NOTES UnifiedJM Soil Classification Major Divisions Symbol Soil Descriptions Coarse- Grained Soils < Gravel & Gravelly Soils < 50% coarse GW Well -graded ravels; ravel/sand mixtures with little or no fines GP Poorly -graded ravels; ravel/sand mixtures with little or no fines GM Silty gravels; poorly -graded ravel/sand/silt mixtures GC Clayey gravels; poorly -graded gravel/sand/clay mixtures 50% passes No. 00 sieve Sand & Sandy Soils > 50% coarse fraction SW Well -graded sands; gravelly sands with little or no fines SP Poorl - raded sands; gravelly sands with little or no fines SM Silt sands; poorly -graded sand/gravel/silt mixtures SC Clayey sands; poorly -graded sand/gravel/clay mixtures Fine- Grained Soils > 50% Silts & Clays LL < 50 ML Inorganic silts; sandy, gravelly or clayey silts CL Lean clays; inorganic, gravelly, sandy, or silty, low to medium - plasticitylays OL Organic, low -plasticity clays and silts passes No. 00 sieve Silts &Clays LL > 50 MH Inorganic, elastic silts; sandy, gravelly or clayey elastic silts CH Fat clays; high -plasticity, inorganic clays OH Organic, medium to high -plasticity clays and silts Highly Organic Soils PT Peat, humus, hydric soils with high organic content tive Density and Consistency Coarse -Grained Soils SPT Blow Counts N) Very Loose: < 4 Loose: 4-10 Medium Dense: 10-30 Dense: 30-50 Very Dense: > 50 Fine -Grained Soils SPT Blow Counts N Very Soft: < Soft: -4 Medium Stiff: 4-8 Stiff: 8-15 Very Stiff: 15-30 Hard: > 30 Particle Boulders: Size > 1 in. Cobbles: 1 to 3 in. Gravel: 3 in. to 5 mm Coarse -Grained Sand: 5 to 0.6 mm Medium -Grained Sand: 0.6 to 0. mm Fine -Grained Sand: 0. to 0.075 mm Silts: 0.075 to 0.005 mm Clays: < 0.005 mm a Moisture — Description Content and Cementation Classification Field Test Dry Absence of moisture, dry to touch Slightly Moist Damp, but no visible moisture Moist Visible moisture Wet Visible free water Saturated Soil is usually below water table Description Field Test Weak Crumbles or breaks with handling or slight finger pressure Moderate Crumbles or breaks with considerable finger pressure Strong Will not crumble or break with finger pressure GS Acronym List grab sample LL Liquid Limit M moisture content NP non -plastic PI Plasticity Index Qp penetrometer value, unconfined compressive strength, tsf V vane value, ultimate shearing strength, tsf Atlas No. B 01400g Pagel 8 Copyright © 0 0 Atlas Technical Consultants CUEIDR IAy APPROVED DATE 03/02/22 FILE NUMBER: Fa-2o21-oo51 pendix VI AASHTO PAVEMENT THICKNESS DESIGN PROCEDURES Pavement Section Design Location: Proposed Mixed -Use Development, Light Duty Average Daily Traffic Count: 400 All Lanes & Both Directions Design Life: 0 Years Percent of Traffic in Design Lane: 50% Terminal Seviceability Index (Pt): .5 Level of Reliability: 95 Subgrade CBR Value: 4 Subgrade Mr: 6,000 Calculation of Design-18 kip ESALs Daily Growth Load Design Traffic Rate Factors ESALs Passenger Cars: 140 .0% 0.0008 993 Buses: 0 .0% 0.6806 0 Panel & Pickup Trucks: 55 .0% 0.01 5,951 -Axle, 6-Tire Trucks: 4 .0% 0.1890 6,705 Emergency Vehicles: 1.0 .0% 4.4800 39,731 Dump Trucks: 0 .0% 3.6300 0 Tractor Semi Trailer Trucks: 0 .0% .3719 0 Double Trailer Trucks 0 .0% .3187 0 Heavy Tractor Trailer Combo Trucks: 0 .0% .9760 0 Average Daily Traffic in Design Lane: 00 Total Design Life 18-kip ESALs: 53,380 Actual Log (ESALs): 4.7 7 Trial SN: .48 Trial Log (ESALs): 4.7 8 Pavement Section Design SN: .61 Design Depth Structural Drainage Inches Coefficient Coefficient Asphaltic Concrete: .50 0.4 n/a Asphalt -Treated Base: 0.00 0. 5 n/a Cement -Treated Base: 0.00 0.17 n/a Crushed Aggregate Base: 4.00 0.14 1.0 Subbase: 10.00 0.10 1.0 Special Aggregate Subgrade: 0.00 0.09 0.9 Atlas No. B 01400g Pagel 9 Copyright © 0 0 Atlas Technical Consultants CUEIDR IAy APPROVED DATE 03/02/22 FILE NUMBER: Fa-2o21-oo51 HTO PAVEMENT THICKNESS DESIGN PROCEDURES Pavement Section Design Location: Proposed Mixed -Use Development, Heavy Duty Average Daily Traffic Count: 400 All Lanes & Both Directions Design Life: 0 Years Percent of Traffic in Design Lane: 50% Terminal Seviceability Index (Pt): .5 Level of Reliability: 95 Subgrade CBR Value: 4 Subgrade Mr: 6,000 Calculation of Design-18 kip ESALs Daily Growth Load Design Traffic Rate Factors ESALs Passenger Cars: 105 .0% 0.0008 745 Buses: 0 .0% 0.6806 0 Panel & Pickup Trucks: 75 .0% 0.01 8,115 -Axle, 6-Tire Trucks: 15 .0% 0.1890 5,14 Emergency Vehicles: .0 .0% 4.4800 79,46 Dump Trucks: 1 .0% 3.6300 3 ,193 Tractor Semi Trailer Trucks: .0% .3719 4 ,071 Double Trailer Trucks 0 .0% .3187 0 Heavy Tractor Trailer Combo Trucks: 0 .0% .9760 0 Average Daily Traffic in Design Lane: 00 Total Design Life 18-kip ESALs: 187,7 7 Actual Log (ESALs): 5. 74 Trial SN: 3.06 Trial Log (ESALs): 5. 78 Pavement Section Design SN: 3.07 Design Depth Structural Drainage Inches Coefficient Coefficient Asphaltic Concrete: 3.00 0.4 n/a Asphalt -Treated Base: 0.00 0. 5 n/a Cement -Treated Base: 0.00 0.17 n/a Crushed Aggregate Base: 4.00 0.14 1.0 Subbase: 1 .00 0.10 1.0 Special Aggregate Subgrade: 0.00 0.09 0.9 Atlas No. B 01400g Page 130 Copyright © 0 0 Atlas Technical Consultants `(E III DIA\ APPROVED J DAM 03/02/22 eolechnicol Fig euMet�: F_zoz,,os, Engineering Report The Geoprofessional Business Association (GBA) has prepared this advisory to help you — assumedly a client representative — interpret and apply this geotechnical-engineering report as effectively as possible. In that way, you can benefit from a lowered exposure to problems associated with subsurface conditions at project sites and development of them that, for decades, have been a principal cause of construction delays, cost overruns, claims, and disputes. If you have questions or want more information about any of the issues discussed herein, contact your GBA-member geotechnical engineer. Active engagement in GBA exposes geotechnical engineers to a wide array of risk -confrontation techniques that can be of genuine benefit for everyone involved with a construction project. Understand the Geotechnical-Engineering Services Provided for this Report Geotechnical-engineering services typically include the planning, collection, interpretation, and analysis of exploratory data from widely spaced borings and/or test pits. Field data are combined with results from laboratory tests of soil and rock samples obtained from field exploration (if applicable), observations made during site reconnaissance, and historical information to form one or more models of the expected subsurface conditions beneath the site. Local geology and alterations of the site surface and subsurface by previous and proposed construction are also important considerations. Geotechnical engineers apply their engineering training, experience, and judgment to adapt the requirements of the prospective project to the subsurface model(s). Estimates are made of the subsurface conditions that will likely be exposed during construction as well as the expected performance of foundations and other structures being planned and/or affected by construction activities. The culmination of these geotechnical-engineering services is typically a geotechnical-engineering report providing the data obtained, a discussion of the subsurface model(s), the engineering and geologic engineering assessments and analyses made, and the recommendations developed to satisfy the given requirements of the project. These reports may be titled investigations, explorations, studies, assessments, or evaluations. Regardless of the title used, the geotechnical-engineering report is an engineering interpretation of the subsurface conditions within the context of the project and does not represent a close examination, systematic inquiry, or thorough investigation of all site and subsurface conditions. Geotechnical-Engineering Services are Performed for Specific Purposes, Persons, and Projects, and At Specific Times Geotechnical engineers structure their services to meet the specific needs, goals, and risk management preferences of their clients. A geotechnical-engineering study conducted for a given civil engineer will not likely meet the needs of a civil -works constructor or even a different civil engineer. Because each geotechnical-engineering study is unique, each geotechnical-engineering report is unique, prepared solely for the client. Likewise, geotechnical-engineering services are performed for a specific project and purpose. For example, it is unlikely that a geotechnical- engineering study for a refrigerated warehouse will be the same as one prepared for a parking garage; and a few borings drilled during a preliminary study to evaluate site feasibility will not be adequate to develop geotechnical design recommendations for the project. Do not rely on this report if your geotechnical engineer prepared it: • for a different client; • for a different project or purpose; • for a different site (that may or may not include all or a portion of the original site); or • before important events occurred at the site or adjacent to it; e.g., man-made events like construction or environmental remediation, or natural events like floods, droughts, earthquakes, or groundwater fluctuations. Note, too, the reliability of a geotechnical-engineering report can be affected by the passage of time, because of factors like changed subsurface conditions; new or modified codes, standards, or regulations; or new techniques or tools. If you are the least bit uncertain about the continued reliability of this report, contact your geotechnical engineer before applying the recommendations in it. A minor amount of additional testing or analysis after the passage of time - if any is required at all - could prevent major problems. Read this Report in Full Costly problems have occurred because those relying on a geotechnical- engineering report did not read the report in its entirety. Do not rely on an executive summary. Do not read selective elements only. Read and refer to the report in full. You Need to Inform Your Geotechnical Engineer About Change Your geotechnical engineer considered unique, project -specific factors when developing the scope of study behind this report and developing the confirmation -dependent recommendations the report conveys. Typical changes that could erode the reliability of this report include those that affect: • the site's size or shape; • the elevation, configuration, location, orientation, function or weight of the proposed structure and the desired performance criteria; • the composition of the design team; or • project ownership. As a general rule, always inform your geotechnical engineer of project or site changes - even minor ones - and request an assessment of their impact. The geotechnical engineer who prepared this report cannot accept for problems that arise because the geotechnical ed about developments the engineer otherwise ATE: U3/UL/LL ndings" Related in This Report ILENUNIBEIR FP-z Iz Ds7 al Opinions begins, geotechnical engineers explore a site's subsurface using various sampling and testing procedures. Geotechnical engineers can observe actual subsurface conditions onl at those specific locations where sampling and testing is performed. The data derived from that sampling and testing were reviewed by your geotechnical engineer, who then applied professional judgement to form opinions about subsurface conditions throughout the site. Actual sitewide-subsurface conditions may differ - maybe significantly - from those indicated in this report. Confront that risk by retaining your geotechnical engineer to serve on the design team through project completion to obtain informed guidance quickly, whenever needed. This Report's Recommendations Are Confirmation -Dependent The recommendations included in this report - including any options or alternatives - are confirmation -dependent. In other words, they are not final, because the geotechnical engineer who developed them relied heavily on judgement and opinion to do so. Your geotechnical engineer can finalize the recommendations onl after observing actual subsurface conditions exposed during construction. If through observation your geotechnical engineer confirms that the conditions assumed to exist actually do exist, the recommendations can be relied upon, assuming no other changes have occurred. Thegeotechnical engineer who prepared this report cannot assume responsibilit or liabilit for confirmation -dependent recommendations if ou fail to retain that engineer to perform construction observation. This Report Could Be Misinterpreted Other design professionals' misinterpretation of geotechnical- engineering reports has resulted in costly problems. Confront that risk by having your geotechnical engineer serve as a continuing member of the design team, to: • confer with other design -team members; • help develop specifications; • review pertinent elements of other design professionals' plans and specifications; and • be available whenever geotechnical-engineering guidance is needed. You should also confront the risk of constructors misinterpreting this report. Do so by retaining your geotechnical engineer to participate in prebid and preconstruction conferences and to perform construction - phase observations. Give Constructors a Complete Report and Guidance Some owners and design professionals mistakenly believe they can shift unanticipated -subsurface -conditions liability to constructors by limiting the information they provide for bid preparation. To help prevent the costly, contentious problems this practice has caused, include the complete geotechnical-engineering report, along with any attachments or appendices, with your contract documents, but be certain to note conspicuousl that ou've included the material for information purposes onl . To avoid misunderstanding, you may also want to note that "informational purposes" means constructors have no right to rely on the interpretations, opinions, conclusions, or recommendations in the report. Be certain that constructors know they may learn about specific project requirements, including options selected from the report, onl from the design drawings and specifications. Remind constructors that they may perform their own studies if they want to, and be sure to allow enough time to permit them to do so. Only then might you be in a position to give constructors the information available to you, while requiring them to at least share some of the financial responsibilities stemming from unanticipated conditions. Conducting prebid and preconstruction conferences can also be valuable in this respect. Read Responsibility Provisions Closely Some client representatives, design professionals, and constructors do not realize that geotechnical engineering is far less exact than other engineering disciplines. This happens in part because soil and rock on project sites are typically heterogeneous and not manufactured materials with well-defined engineering properties like steel and concrete. That lack of understanding has nurtured unrealistic expectations that have resulted in disappointments, delays, cost overruns, claims, and disputes. To confront that risk, geotechnical engineers commonly include explanatory provisions in their reports. Sometimes labeled "limitations;' many of these provisions indicate where geotechnical engineers' responsibilities begin and end, to help others recognize their own responsibilities and risks. Read these provisions closel . Ask questions. Your geotechnical engineer should respond fully and frankly. Geoenvironmental Concerns Are Not Covered The personnel, equipment, and techniques used to perform an environmental study - e.g., a "phase -one" or "phase -two" environmental site assessment - differ significantly from those used to perform a geotechnical-engineering study. For that reason, a geotechnical-engineering report does not usually provide environmental findings, conclusions, or recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Unanticipated subsurface environmental problems have led to project failures. If you have not obtained your own environmental information about the project site, ask your geotechnical consultant for a recommendation on how to find environmental risk -management guidance. Obtain Professional Assistance to Deal with Moisture Infiltration and Mold While your geotechnical engineer may have addressed groundwater, water infiltration, or similar issues in this report, the engineer's services were not designed, conducted, or intended to prevent migration of moisture - including water vapor - from the soil through building slabs and walls and into the building interior, where it can cause mold growth and material -performance deficiencies. Accordingly, proper implementation of the geotechnical engineer's recommendations will not of itself be sufficient to prevent moisture infiltration. Confront the risk of moisture infiltration by including building -envelope or mold specialists on the design team. Geotechnical engineers are not building -envelope or mold specialists. GEOPROFESSIONAL Iff:VA AFM BUSINESS - ASSOCIATION Telephone: 301 /565-2733 e-mail: info@geoprofessional.org wwwgeoprofessional.org Copyright 2019 by Geoprofessional Business Association (GBA). Duplication, reproduction, or copying of this document, in whole or in part, by any means whatsoever, is strictly prohibited, except with GBA's specific written permission. Excerpting, quoting, or otherwise extracting wording from this document is permitted only with the express written permission of GBA, and only for purposes of scholarly research or book review. Only members of GBA may use this document or its wording as a complement to or as an element of a report of any kind. Any other firm, individual, or other entity that so uses this document without being a GBA member could be committing negligent or intentional (fraudulent) misrepresentation.