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HomeMy WebLinkAboutCC - Storm Drainage Calcs CJK! ENGINEERING P . C . Civil Engineering * Project Management DRAINAGE CALCULATIONS FOR: DRIFTWOOD TOWNHOMES SUB Meridian, Idaho May 28, 2026 �SS�ONAI fop fN �o� vCENSfpy�. 23 os-2d-z6 or�o My S. f Prepared for: Brighton Development 126ol W. Explorer Drive Suite 200 Boise, ID 83713 (208)-378-4000 Prepared by: CK Engineering, P.C. Jeremy Foster, P.E. 6700 W. State St. Boise, ID 83714 (208)-639-1992 CK Engineering 6700 W.State St,Boise,ID 83714 208.639.1992 CK ENGINEERING Drainage Narrative for DRIFTWOOD TOWNHOMES SUBDIVISION Driftwood Townhomes Subdivision consists of 2 existing drainage areas and 16 new drainage areas.The existing drainage areas are handled by Existing Storm Drain Pond #1 that was sized to handle Wind Drift St drainage, drainage over the existing pond area itself and portions of the future Driftwood Townhomes area. DA#2-#11 are new drainage areas directed to Existing Storm Drain Pond #1, DA#1 is directed to Storm Tech #1, Drainage Area #8 is directed to Seepage Bed #1, and DA#12-DA#16 are directed to Storm Tech #2. All drainage facilities will be private. Please see the attached Drainage Exhibit. The geotechnical report that was referenced is from Atlas Technical Consultants, LLC on March 9, 2021. Design percolation rates varied across the sight from 2.4 inches/hr to 8 inches/hr. Based on the location of the test pits in relation to the drainage facilities, the appropriate rate was used to size the drainage facilities. Please see the attached geotech report. GW varied across the site. Please see the attached GW Report from Natural Resource Solutions, LLC on November 14, 2022. Existing Storm Drain Pond #i: ACHD Stormwater spreadsheet was utilized to calculate the runoff volume for the pond and calculate the required pond volume. This pond has a provided pond volume of 11,86o CF from a total design drainage area of 162,109 SF. The Existing DA#1 and Existing DA#2 handle the runoff from Wind Drift St. and the Existing Pond Area. The remaining Drainage areas (DA#2 — DA#11) that contribute to the pond from Driftwood Sub along with the 2 existing Drainage Areas total to 159,645 SF. Existing Storm Drain Pond #1 is sized to handle the runoff that will be directed to it from these new drainage areas. Storm Tech #1: Drainage Area #1 will be directed to Storm Tech #1. ACHD Stormwater spreadsheet was used to calculate the too year runoff volume for this facility. ADS Stormtech Calculators were used to take the required runoff volume and calculate the required number of chambers. 1,895 CF of storage is required which will need 21, SC-800 chambers to give a provided storage volume of 2017.18 CF. Please see the attached calculations for the required volume, sand and grease trap sizing and chambers calculations. Seepage Bed #1: Drainage Area #8 will collect stormwater runoff into a single CB#8 and will go through a l000 gallon sand and grease trap into a seepage bed that was designed using ACHD stormwater spreadsheets and methodology to calculate a required storage volume. Seepage Bed #1 is required to have a storage CK ENGINEERING 6700 W.State St Boise,ID 83714 208.639.1992 CK ENGINEERING volume of 1,159 CF. A bed 15'Wx4'Dx45'L provides the storage required to handle the too year runoff volume and will drain go% of the volume in 48 hours. Storm Tech #2: Drainage Areas #12-#16 will be directed to Storm Tech #2. ACHD Stormwater spreadsheet was used to calculate the too year runoff volume for this facility. ADS Stormtech Calculators were used to take the required runoff volume and calculate the required number of chambers. 2,078 CF of storage is required which will need 23, SC-800 chambers to give a provided storage volume Of 2,192.69 CF. No sand and grease trap is required as this will receive roof and rear lot drainage. Please see the attached calculations for the required volume and chambers calculations. Attached: 1. Storm drain calculations 2. 11x17 colored drainage area exhibit 3. Geotechnical Engineering Report from Atlas Technical Consultants, LLC. 4. GW Monitoring Report from Natural Resource Solutions. End of Narrative. EK ENGINEERING 6700 W.State St Boise,ID 83714 208.639.1992 EK ENGINEERING DRAINAGE CALCULATIONS CK ENGINEERING 6700 W.State St Boise,ID 83714 208.639•1992 ACHD Calculation Sheet for Finding Peak Discharge/Volume-Rational Method NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology.These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. Calculate Post-Development Flows(for pre-development flows,Increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name DRIFTWOOD TOWNHOMES-DAL Storm Techsl 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm(100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities(25 max) Click to Show More Subbasins Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 S 6 7 8 9 30 5 Area of Drainage Subbasin(SF or Acres) SF 26,540 Acres 0.61 6 Determine the Weighted Runoff Coefficient(C) 0.90 C=[(C1xA1)+(C2xA2)+(CnxAn)I/A Weighted Avg 0.90 7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 User Calculate min [lo wn Estimated Runoff Coefficients for Various Surfact � __-- Type of Surface Runoff Coefficients"( Determine the average rainfall Intensity(1)from IDF Curve based on Tc 1 258 r Business Downtown areas 0.70-0.95 9 Calculate the Post-Development peak discharge(QPeak) Oar„ SAI 0S Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 30 Calculate total runoff Vol(V)(for sizing primary storage) v 1,895 Multi-family 0.60-0.75 V=Cl(Tc=60)Ax3600 Residential rural 0.25-OAO 11 Calculate Volume of Runoff Reduction Vrr Apartment Dwelling Areas 0.70 Industrial and Commercial Enter Percentile Storm 1(95th percentile=0.60 in) 95th 0.60 in Light areas 0.80 Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) V 2,184 h' Heavy areas 0.90 Parks,Cemeteries 0.10-0.25 0.00 cfS 12 Detention:Approved Discharge Rate to Surface Waters(if applicable) Playgrounds 0.20-0.35 Railroad yard areas 0.20-0.40 13 Volume Summary Unimproved areas 0.10-0.30 Surface Storage:Basin streets Basin Forebay V 190 ft' Asphalt 0.95 Concrete 0.95 Primary Treatment/StorageBasin V 1,706 ft' Brick 0.95 Subsurface Storage Roofs 0.95 Volume Without Sediment Factor(See BMP 20 Tab) V 1,895 fts Gravel 0.75 Fields:Sandy soil Soil Type slope A B E D Flat:O-2% 0.04 0.07 0 Average:2-6% 0.09 0.12 0. Stee :Nr% 0.13 0.18 0. Adapted from ASCE D:\BRIGHTON CORP\Settlers Park Sub\Documents\DRAINAGE CALLS\townhomes drainage talcs\DRIFTWOOD\DRIFTWOOD-BEDg1 05-27-26 5/27/2026,4:45 PM Version 10.0,May 2018 ACHD Calculation Sheet for Sand/Grease Traps NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. User input in yellow cells. 1 Project Name DRIFTWOOD TOWNHOMES-DA1 Storm Tech01 2 Enter number of Sand/Grease Traps(25 max) 1 Number of Peak Flow Baffle Throat 1 Velocity Is the Vault Size Spacing width Area(ftZ) 0.5 fps Velocity S/G Traps Q-cfs inch inch max. okT 1000 G 1 1.41 20 48 6.67 0.21 Reference for Throat widths(inch) Boise ADS Vault Lar-ken WQU, 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 D:\BRIGHTON CORP\Settlers Park Sub\Documents\DRAINAGE CALCS\townhomes drainage calcs\DRIFTW00D\DRIFTW00D-BED#105-27- 26 5/27/2026,4:46 PM Version 10.0,May 2018 AADSDRIFTWOOD Storm Tech#1 STORMTECH CHAMBERS User Inputs Results Chamber Model: SC-800 System Volume and Bed Size Outlet Control Structure: Yes Project Name: DRIFTWOOD SUB Installed Storage Volume: 2017.18 cubic ft. Engineer: N/A Storage Volume Per Chamber: 50.60 cubic ft. Project Location: Idaho Number Of Chambers Required: 21 Measurement Type: Imperial Number Of End Caps Required: 6 Chamber Rows: 3 Required Storage Volume: 1895 cubic ft. Maximum Length: 57.50 ft. Stone Porosity: 40% Maximum Width: 15.85 ft. Stone Foundation Depth: 6 in. Approx.Bed Size Required: 911.34 square ft. Stone Above Chambers: 6 in. Design Constraint Dimensions: (22 ft.x 57 ft.) Average Cover Over Chambers: N/A. System Components Amount Of Stone Required (0%Overage): 87 cubic yards (Cubic yard to ton factor:1.4): 121.05 tons Volume Of Excavation(Not Including 127 cubic yards Fill): Total Non-woven Geotextile Required: 317 square yards Woven Geotextile Required(excluding 21 square yards Isolator Row): Woven Geotextile Required(Isolator 35 square yards Row): Total Woven Geotextile Required: 56 square yards Impervious Liner Required: 0 square yards EMBEDMENT STONE SHALL BEA CLEAN.CRUSHED AND ANGULAR GRANULAR WELL-GRADEDSdUAGGREGATE MIXTURES c16%FINES WI STONE TH AN AASHTO M48 DESIGNATION BETWEEN NO AND#57 COMPACT IN 6'(150 mm)MAX LIFTS TO 95%STANDARD PROCTOR DENSITY SEE THE TABLE OF ACCEPTABLE FILL MATERIALS CHAMBERS SHALL MEET THE REQUIREMENTS OF ASTM F208 POLYPROPLENE(PP)CHAMBERS CHAMBERS SHALL BE DESIGNED IN ACCORDANCE WITH ASTM F2787 OR ASTM F2922 POLYETHYLENE(PE)CHAMBERS STANDARD PRACTICE FOR STRUCTURAL DESIGN OF THERMOPLASTIC CORRUGATED WALL STORMWATER COLLECTION CHAMBERS' ADS GEOSYNTHETICS 601T NON-WOVEN GEOTEXTILE ALL AROUND CLEAN CRUSHED, PAVEMENT LAYER(DESIGNED ANGULAR STONE BY S17E DESIGN ENGINEER) 1 i ��'� �lyira`•�� a,��i �#o � `� 1s. e IyQOn 4p pySyll�h„�.4 �apuy, I(dTl{■ �/�p a4u 11 al a_npT{nw f(� µdtyp�X iq�uu,�a u4s•i J/O�aA p�%�T011�h1(y 1 (375 mm)IAN• (2A.)MAX 6(150 mL.)MIN 37 PERIMETER STONE IBM mm) EXCAVATION WALL (CAN BE SLOPED OR VERTICAL) t DEPITEDTH OF STONE NINER6'(150 DETERMINED IF BY 517E DESIGN ENGINEER C(750 mm)MIN 12'OW—)MIN SC SDOENDCAP (75 r)MIN 51'(1295 mm) 12'(000mm)MIN SITE DESIGN ENGINEER IS RESPONSIBLE FORE14SURING THE REQUIREDBEARING CAPACITY OF SUBGRADE SOILS 'MINIMUM COVER TO BOTTOM OF FLEXIBLE PAVEMENT FOR UNPAVED INSTALLATIONS WHERE RUTTING FROM VEHICLES MAYOCCUR INCREASE COVER TO 2,r(6W mm) ACHD Calculation Sheet for Finding Peak Discharge/Volume-Rational Method NOTE:This worksheet Is Intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology.These calculations shall establish a minimum requirement.The Engineers methodology must result in facilities that meet or exceed these calculations In order to be accepted. Calculate Post-Development Flows[for pre-development flows,Increase number of storage facilities to create new tab) User Input in yellow cells. 1 Project Name DRIFTWOOD TOWNHOMES-DA8-SD BED pl 2 Is area drainage basin map provided? YES [map must be included with stormwater calculations) 3 Enter Design Storm(100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities(25 max) Click to Show More Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 6 7 8 9 30 5 Area of Drainage Subbasin(SF or Acres) SF 21,800 Acres 0.50 6 Determine the Weighted Runoff Coefficient(C) 0.67 C=[(CSxAl)+(C2xA2)+(CnxAn)]/A Weighted Avg 0.67 7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 User Calculate min [10 Min. Estimated Runoff Coefficients for Various Surface Type of Surface Runoff Coefficients"( 8 Determine the average rainfall intensity(1)from IDF Curve based on Tc 1 2.58 2.58 InJhr Business Downtown areas 0.70-0.95 9 Calculate the Post-Development peak discharge(QPeak) 00.1, 0.87 ds Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 30 Calculate total runoff vol(V)(for sizing primary storage) 1,159 ft Multi-family 0,50.0.75 V=CI(Tr-60)Ax36W Residential(rural) 0.25-0,40 11 Calculate Volume of Runoff Reduction Vrr Apartment Dwelling Areas o.70 Industrial and Commercial Enter Percentile Storm I(95th percentile=0.60 in) 95th 0.60 in Light areas 0.80 Enter Runoff Reduction Vol(95th Percentile=0.604n x Area x C) V„ 724 'ft Heavy areas 0.90 12 Detention:Approved Discharge Rate to Surface Waters(if applicable) Parks Cemeteries 0_10-0.25 0.00 cgs Playgrounds 0.20-0.35 Railroad yard areas_ 0.20-0.40 13 Volume Summary Unimproved areas 0.10-0.30 Surface Storage:Basin Streets Basin Foreba V 116 ft$ Asphalt 0.95 Y Concrete 0.95 Primary Treatment/Storage Basin V 1,043 It, Brick 0.95 Subsurface Storage Roofs 0.95Gravel 0.75 Volume Without Sediment Factor(See BMP 20 Tab) V 1,159 fts Fields:Sandy sal Soil type Slope A B C D Flat:0-2Y 0.04 0.07 Average:2-69i 0.09 0.12 See :>69L 0.13 0.18 Adapted from ASCE D:\BRIGHTON CORP\Settlers Park Sub\Documents\DRAINAGE CALCS\Townhomes Drainage Calcs\DRIFTWOOD\DRIFTWOOD BEOa2 05-27-26 5/28/2026,8:26 AM Version 10.0,May 2018 ACHD Calculation Sheet for Sand/Grease Traps NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology. These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. User input in yellow cells. 1 Project Name DRIFTWOOD TOWNHOMES-DA8-SO BED#1 2 Enter number of Sand/Grease Traps(25 max) 1 Number of Peak Flow Baffle Throat Velocity Is the Vault Size Spacing width Area(fe) 0 55 fps Velocity S/G Traps Q-cfs inch inch max. ok? 1000 G 1 0.87 20 48 6.67 0.13 Reference for Throat widths(inch) Boise ADS Vault Lar-ken WQU, BMP 16 1000 G 48.0 50.5 n/a 1500 G 60.0 61.5 n/a QU1000 n/a n/a 60 QU1500 n/a n/a 60 D:\BRIGHTON CORP\Settlers Park Sub\Documents\DRAI NAG E CALCS\Townhomes Drainage Calcs\DRIFTWOOD\DRIFTWOOD BED#2 05• 27-26 5/28/2026,8:26 AM Version 10.0,May 2018 ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology.These calculations shall establish a minimum requirement.The Engineer's methodology must result in facilities that meet or exceed these calculations In order to be accepted. Note this spreadsheet pulls information from the"Peak Q,V"tab Calculate Post-Development Flows(for pre-development Rows,Increase number of storage facilities to create new tab) User Input in yellow cells. 1 Project Name DRIFTWOOD TOWNHOMES-DAB-SO BED#1 2 Enter number of Seepage Beds(25 max) 1 3 Design Storm 100 4 Weighted Runoff Coefficient C 067 Link to; [QV QV TR55 5 Area A(Acres) 050 acres 6 Approved discharge rate(if applicable) 000 cfs 7 Is Seepage Bed in Common Lot? Yes V 1,159 it' 0%Sediment 8 Set Total Design Width of All Dram Rock W 15 0 ft 9 Set Total Design Depth of All Drain Rock D 40 ft Rock Only,Do Not Include Filter Sand Depth or Cover 10 Void Ratio of Dram Rock Voids ❑34 0.4 for 1 5"-2"drain rock and 3/4"Chips 11 Design Infiltration Rate(8 in/hr max) Perc 800 in/hr 12 Size of WQ Perf Pipe(Perf 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 257 It'jft 15 Calculate Design Length L 45 ft Override Value Required Jar Chambers 16 Variable Infiltration Window L SWL 45 ft 17 Variable Infiltration Window W SWW ISO ft 18 Time to Drain 2 3 hours 90%volume in 48-hours minimum 19 Length of WQ&Overflow Perf Pipes 45 92 ft 20 Perf Pipe Checks.Qperf>=Qpeak. where Qperf=CdxAxV(2xgxH) Optional Storage Chambers Note:This assumes chambers are organized in a rectangular layout. 1-StormTech, 1 Type of Chambers SC740 2 Volume to Store V 0 fts 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 ft,/Unit 6 Chamber Storage Volume,With Rock,Per Manuf 74.90 fts/Unit 7 Total Number of Units Required 0 ea 8 Area of Infiltration Aperc ftz 9 Volume Infiltration Vperc 0 fts/hr 10 Time to Drain hours 90%volume in 48-hours minimum D:\BRIGHTON CORP\Settlers Park Sub\Documents\DRAINAGE CALCS\Townhomes Drainage Calcs\DRIFTWOOD\DRIFTWOOD BEDg2 05-27-26 5/28/2026,8:27 AM Version 10.0,May 2018 ACHD Calculation Sheet for Finding Peak Discharge/Volume-Rational Method NOTE:This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the Engineer's calculation methodology.These calculations shall establish a minimum requirement.The Engineers methodology must result in facilities that meet or exceed these calculations in order to be accepted. blculate Post-Development Flows{for pre-development flows,Increase number of storage facilities to create new tab) User input in yellow cells. 1 Project Name Driftwood- Stormlech a2 (Chambers Required Storage Volume) 2 Is area drainage basin map provided? YES (map must be included with stormwater calculations) 3 Enter Design Storm(100-Year or 25-Year With 100-Year Flood Route) 100 4 Enter number of storage facilities(25 max) Click to Show More Subbasins Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin DA 12 DA 13 DA 14 DA 15 DA 16 6 7 8 9 10 5 Area of Drainage Subbasin(SF or Acres) SF 5,082 5,52S 6,166 6,167 6,162 Acres 0.67 6 Determine the Weighted Runoff Coefficient(C) 0.90 0.90 0.90 0.90 0.90 C=[(C1xA1)+(C2xA2)+(CnxAn)j/A Weighted AvgJ 0.90 7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default SO User calculate min [10 Minim Estimated Runoff Coefficients for Various Surfact - Type of Surface Runoff Coefficients"( 8 Determine the average rainfall Intensity(1)from IDF Curve based on Tc I 2.S8 2.58 In r Business Downtown areas O 70-0.95 V Calculate the Post-Development peak discharge(QPeak) Qi a* 1.SS cis Urban neighborhoods 0.50-0.70 Residential Single Family 0,35-0.50 10 Calculate total runoff vat(V)(for sizing primary storage) V 2,078 ft Mu1ti-famil 0.60-0.75 V=Ci(Tc=60)Ax3600 Residential rural 0.25-0,40 11 Calculate Volume of Runoff Reduction Vrr Apartment Dwelling Areas 0.70 Industrial and Commercial Enter Percentile Storm 1(95th percentile=0.60 in) 95th 0.60 in Light areas 0.80 Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) V•; 1,299 ft, Heavy areas 0.90 12 Detention:Approved Discharge Rate to Surface Waters(if applicable) 000 cis Parks,cemeteries 0,10-0.25 Playgrounds 0.20-0.35.. Railroad yard areas 0.20-0.40 13 Volume Summary Unimproved areas 0,10-0.30 Surface Storage:Basin streets Asphalt 0.95 Basin Farebay V 208 its Concrete 0.95 Primary Treatment/StorageBasin V 1,870 fta Brick 0.95 Subsurface Storage Roofs 0.95 Gravel Volume Without Sediment Factor(See BMP 20 Tab) V 2,078 Ad ffa Fields:Sandy soil Soil Soll Type Slope A B C O Flat:G-211 0.04 c 0.11 0. Average:2.6% o.09 0.12 0.15 0 Stee :>6% 0.13 0.18 0.23 0 Adapted from ASCE D:\BRIGHTON CORP\Settlers Park Sub\Documents\DRAINAGE CALCS\townhomes drainage talcs\DRIFTWOOD\DRIFTWOOD_REQUIRED STORAGE VOLUME_CHAMBERS_w27/2826,1:59 PM Version 10.0,May 2018 AADS DRIFTWOOD- Storm Tech#2 -CHAMBERS User Inputs Results Chamber Model: SC-800 System Volume and Bed Size Outlet Control Structure: Yes Project Name: DRIFTWOOD SUB Installed Storage Volume: 2192.69 cubic ft. Engineer: N/A Storage Volume Per Chamber: 50.60 cubic ft. Project Location: Idaho Number Of Chambers Required: 23 Measurement Type: Imperial Number Of End Caps Required: 6 Chamber Rows: 3 Required Storage Volume: 2078 cubic ft. Maximum Length: 64.61 ft. Stone Porosity: 40% Maximum Width: 15.85 ft. Stone Foundation Depth: 6 in. Approx.Bed Size Required: 987.85 square ft. Stone Above Chambers: 6 in. Design Constraint Dimensions: (18 ft.x 75 ft.) Average Cover Over Chambers: -2575.00 ft. System Components Amount Of Stone Required (0%Overage): 94 cubic yards (Cubic yard to ton factor:1.4): 130.68 tons Volume Of Excavation(Not Including 138 cubic yards Fill): Total Non-woven Geotextile Required: 344 square yards Woven Geotextile Required(excluding 21 square yards Isolator Row): Woven Geotextile Required(Isolator 40 square yards Row): Total Woven Geotextile Required: 60 square yards Impervious Liner Required: 0 square yards EMBEDMENT STONE SHALL SEA CLEAN.CRUSHED AND ANGULAR GRANULAR WELLI)RADEOSOUAGGREGATE MIXTURES c%%FINES STONE WITH AN AASHTO M43 DESIGNATION BETWEEN#SAND N57 COMPACT IN 6'(150 mm)MAX GIFTS TO 95%STANDARD PROCTOR DENSITY SEE THE TABLE OF ACCEPTABLE FILL MATERIALS CHAMBERS SHALL MEET THE REQUIREMENTS OF ASTM F2418 POLYPRCPLENE(PP)CHAMBERS CHAMBERS SHALL BE DESIGNED IN ACCORDANCE WITH ASTM F2787 OR ASTM F2922 POLYETHYLENE(PE)CHAMBERS 'STANDARD PRACTICE FOR STRUCTURAL DESIGN OF THERMOPLASTIC CCRRUGATED WALL STORMWATER COLLECTION CHAMBERS' ADS GEOSYNTHETICS 601T NON-MOVEN GEOTEXTILE ALL AROUND CLEAN CRUSHED, PAVEMENT LAYER(DESIGNED ANGLIAR STONE BY SITE DESIGN ENGINEER) 1 { .•aM7'1'"NAM 1 by //An8ys411�h� n �eb> 1 7IX �snli onll II cnp./(per 1 IL Mp N A�bp�AO Gu /� Oonll�b nB�Auy< (375 mm)MIN' (24.)MAX 6'(150 mm)MIN 33" PERIMETER STONE (838 mm) EXCAVATION WALL (CAN BE SLOPED OR VERTICAL) DEPTH OF STONE TO BE DETERMINED BY SITE DESIGN ENGINEER 6'(150 mm)MN 12'PW—)MN SC-8W END CAA (75 mm)MN 51'(1295 mm) 12.(30Dmm)MIN SITE DESIGN ENGINEER IS RESPONSIBLE FOR ENSURING THE REOUIREO BEARING CAPACITY OF SUBGRADE SOILS 'MNIMUM COVER TO BOTTOM OF FLEXIBLE PAVEMENT FOR UNPAVED INSTALLATIONS WHERE RUTTING FROM VEHICLES MAY OCCUR INCREASE COVER TO 2.1'(6W mm) CK ENGINEERING DRAINAGE EXHIBIT CK ENGINEERING 6700 W.State St Boise,ID 83714 208.639•1992 1 1 C 1 : 1 1 T �'lllfflillllil r ■�., ``FB I5=7 �I► � r l♦ �`W4`w I lom ��� 11 • fsI' : 22 If '° �w1����/�i �/%AK rl4iml, zee " �♦ r , , E■III■� ■�I■�1♦■ � ' 1 - �� 1��' ��IN / ..��� ��� Ij / I �'---- I ,OV ►� 1/ t- t • lid / / ■.�±�_ ==i �11 '= III ' ;��Iinl11* IIIY - � f /■I■ I - Irr.cT1 = - §�■ .11. _ 1 /r1 1 — ' 1 / � , %.�.JI r' ► ;.IrS ��'�heir Elm nllll ! 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IIL im rN rw N 1 .0 is 11 i_ !■Ap " ,I �n� a■i , i �" ➢ 1;,. 4 -- �I Ll o Lice � ,a�■1 ',��Il�; / -D— ',-�;,.'�----- I— I`.; 7 .... � i//////////.%//////// ////////I�iiiiii>•iiiiiii�////////%I ///� �/ 1 i MIN®R :�� / _fifififirl" h e.� A ��� /// �� -- -----------------------�,�� 9101 00r.,r. - 1 CK ENGINEERING GEOTECHNICAL REPORT CK ENGINEERING 6700 W.State St Boise,ID 83714 208.639•1992 !1F Ik GEOTECHNICAL INVESTIGATION MIXED-USE DEVELOPMENT 870 Ustick Road Meridian, ID PREPARED FOR: Mr. Rod Givens Alturas Construction, LLC 500 East Shore Drive, Suite 100 Eagle, ID 83616 PREPARED BY: Atlas Technical Consultants, LLC March 9, 2021 2791 South Victory View Way B210474g Boise, ID 83709 urn 1111 2791 South Victory View Way Boise, ID 83709 (208)376-4748 1 oneatlas com March 9, 2021 Atlas No. B210474g Mr. Rod Givens Alturas Construction, LLC 500 East Shore Drive, Suite 100 Eagle, ID 83616 Subject: Geotechnical Investigation Mixed-Use Development 870 Ustick Road Meridian, ID Dear Mr. Givens: 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 February 25 and 26, 2021. 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. �SS�ONAL FNc Respectfully submitted, 4�o�C \CENSf0 14898 3/9/2021 0 F OF Clinton Wyllie, PG Elizabeth Brown, ETH Staff Geologist Geotechnical Services Distribution: Jon Wardle, Brighton Development(PDF Copy) Page 1 CONTENTS 1. INTRODUCTION................................................................................................................. 1 1.1 Project Description..................................................................................................... 1 1.2 Authorization.............................................................................................................. 1 1.3 Scope of Investigation................................................................................................ 1 2. SITE DESCRIPTION........................................................................................................... 2 2.1 Site Access................................................................................................................ 2 2.2 Regional Geology....................................................................................................... 2 2.3 General Site Characteristics....................................................................................... 2 2.4 Regional Site Climatology and Geochemistry............................................................. 3 3. SEISMIC SITE EVALUATION ............................................................................................ 3 3.1 Geoseismic Setting .................................................................................................... 3 3.2 Seismic Design Parameter Values............................................................................. 3 4. SOILS EXPLORATION....................................................................................................... 4 4.1 Exploration and Sampling Procedures........................................................................ 4 4.2 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 5.2 Soil Infiltration Rates .................................................................................................. 6 5.3 Infiltration Testing....................................................................................................... 6 6. FOUNDATION AND SLAB DISCUSSION AND RECOMMENDATIONS............................ 7 6.1 Foundation Design Recommendations....................................................................... 7 6.2 Crawl Space Recommendations ................................................................................ 9 6.3 Floor Slab-on-Grade................................................................................................... 9 7. PAVEMENT DISCUSSION AND RECOMMENDATIONS................................................... 9 7.1 Flexible Pavement Sections......................................................................................10 7.2 Common Pavement Section Construction Issues......................................................10 8. CONSTRUCTION CONSIDERATIONS .............................................................................11 8.1 Earthwork..................................................................................................................11 8.2 Dry Weather..............................................................................................................12 8.3 Wet Weather.............................................................................................................12 8.4 Soft Subgrade Soils...................................................................................................12 8.5 Frozen Subgrade Soils..............................................................................................13 8.6 Structural Fill.............................................................................................................13 8.7 Backfill of Walls.........................................................................................................14 8.8 Excavations...............................................................................................................15 Atlas No 13210474g Page I i Copyright U 2021 Atlas Technical Consultants 8.9 Groundwater Control.................................................................................................15 9. GENERAL COMMENTS....................................................................................................16 10. REFERENCES.................................................................................................................17 TABLES Table 1 —Seismic Design Values................................................................................................4 Table 2—Groundwater Data.......................................................................................................6 Table 3—Infiltration Test Results................................................................................................7 Table 4—Soil Bearing Capacity..................................................................................................8 Table 5—AASHTO Flexible Pavement Specifications...............................................................10 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 Design Appendix VI Important Information About This Geotechnical Engineering Report Atlas No. 13210474g Page Iu Copyright©2021 Atlas Technical Consultants 1. INTRODUCTION This report presents results of a geotechnical investigation and analysis in support of data utilized in design of structures as defined in the 2018 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 northern portion of the City of Meridian, Ada County, ID, and occupies a portion of the SE'/4SW% of Section 36, Township 4 North, Range 1 West, Boise Meridian. Atlas previously conducted a subsurface geotechnical investigation on a portion of this site in April 2004. This project will consist of construction of a mixed-use development comprised of commercial structures in the southeastern portion of the site and residential structures in the remainder of the site. The site to be developed is approximately 9.001 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. Rod Givens of Alturas Construction, LLC to Monica Saculles of Atlas Technical Consultants(Atlas), on February 23, 2021. Said authorization is subject to terms, conditions, and limitations described in the Professional Services Contract entered into between Alturas Construction, LLC and Atlas. Our scope of services for the proposed development has been provided in our proposal dated February 19, 2021 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. Atlas No B210474g Page 1 1 Copyright©2021 Atlas Technical Consultants 2. SITE DESCRIPTION 2.1 Site Access Access to the site may be gained via Interstate 84 to the Ten Mile Road exit. Proceed north on Ten Mile Road approximately 2.8 miles to its intersection with Ustick Road. From this intersection, proceed east on Ustick Road approximately 1.5 miles to Venable Lane. The site occupies the northwestern corner of this intersection. The location is depicted on site maps 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 200 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 2 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 2 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 the "Gravel of Whitney Terrace" as mapped by Othberg and Stanford (1993). Sediments of the Whitney terrace consist of sandy pebble and cobble gravel. The Whitney terrace is the second terrace above modern Boise River floodplain, is thickest toward its eastern extent, and is mantled with 2-6 feet of loess. 2.3 General Site Characteristics The site to be developed is approximately 9.001 acres in size. Currently, the site exists as bare land. The surrounding properties consist of existing residential and commercial properties. Vegetation on the site consists of native weeds and grasses. The site is relatively 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 are planned as part of the development. Atlas No. 6210474g Page 12 Copyright©2021 Atlas Technical Consultants �T�131. 2.4 Regional Site Climatology and Geochemistry According to the Western Regional Climate Center, the average precipitation for the Treasure Valley is on the order of 10 to 12 inches per year, with an annual snowfall of approximately 20 inches and a range from 3 to 49 inches. The monthly mean daily temperatures range from 21'F to 95°F, with daily extremes ranging from roughly -250F 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 62 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 7.2 to 8.2. 3. SEISMIC SITE EVALUATION 3.1 Geoseismic Setting Soils on site are classed as Site Class D in accordance with Chapter 20 of the American Society of Civil Engineers (ASCE) publication ASCE/SEI 7-16. 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 (2008), includes a peak ground acceleration map. The map for 2% probability of exceedance in 50 years in the Western United States in standard gravity (g) indicates that a peak ground acceleration of 0.199 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 2018 IBC. Design spectral response acceleration parameters as presented in the 2018 IBC are defined as a 5%damped design spectral response acceleration at short periods, SDs, and at 1-second period, So,. 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 B210474g Page 13 Copyright r'2021 Atlas Technical Consultants Table 1 —Seismic Design Values Seismic Design Parameter Design Value Site Class D"Stiff Soil' Ss 0.292(g) Si 0.106(g) Fa 1.566 Fv 2.387 SMs 0.457 SM, 0.254 Sys 0.305 SD1 0.169 4. SOILS EXPLORATION 4.1 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 pits sites were selected by Mr. Jon Wardle of Brighton Development and provided to Atlas via a site map. Actual 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. 4.2 Laboratory 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. B210474g Page 14 Copyright @ 2021 Atlas Technical Consultants 4.3 Soil and Sediment Profile The profile 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 Whitney Terrace. Lean clay soils were observed at ground surface. These soils were dark brown, slightly moist to moist, and medium stiff to very stiff,with fine-grained sand. Organics were noted to depths of up to 2.2 feet bgs. Sandy silt soils were found beneath lean clays in test pits 1, 2, and 3. These soils were tan, dry to slightly moist, and very stiff to hard, with fine-grained sand. Moderate calcic cementation was encountered within this horizon in test pits 1 and 2. Poorly graded gravel with sand sediments were encountered at depth in the test pits. These sediments were tan to red-brown or brown, slightly moist to saturated, and medium dense, with fine to coarse-grained sand, fine to coarse gravel, and 8-inch minus cobbles. 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. Groundwater encountered did not exhibit obvious signs of contamination. 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 encountered in test pits at depths ranging from 8.2 to 10.2 feet bgs. Soil moistures in the test pits were generally slightly moist to moist within surficial soils. Within the poorly graded gravels with sand, soil moistures graded from slightly moist to saturated as the water table was approached and penetrated. 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. B210474g Page 15 Copyright to 2021 Atlas Technical Consultants �rvTCJ� Atlas has previously performed 5 geotechnical investigations within 0.35 mile of the project site. Information from these investigations has been provided in the table below. Table 2—Groundwater Data Date Approximate Distance Direction from Site Groundwater from .• April 2004 Onsite N/A 7.6 to 10.7 January 2006 0.20 West 5.9 to 7.9 February 2006 0.30 Southwest 6.0 to 6.4 January 2021 0.30 West 7.9 to 10.6 April 2019 0.33 Northwest 6.9 to 8.7 Atlas performed groundwater monitoring during the previous investigation performed on the project site from April 2004 to September 2004. During this monitoring, groundwater was measured at depths ranging from 6.2 to 10.76 feet. For construction purposes, groundwater depth can be assumed to remain greater than 5.5 feet bgs throughout the year. Since this is an estimated depth and seasonal groundwater levels fluctuate, actual levels should be confirmed by periodic groundwater data collected from piezometers installed in the test pits. If desired, Atlas is available to perform this monitoring. 5.2 Soil Infiltration Rates Soil permeability, which is a measure of the ability of a soil to transmit a fluid, was tested in the field. For this report, an estimation of infiltration is also 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 2 inches per hour. Sandy silt soils will commonly exhibit infiltration rates from 2 to 4 inches per hour; though calcium carbonate cementation may reduce this value to near zero. Poorly graded gravel with sand sediments typically exhibit infiltration values in excess of 12 inches per hour; though the presence of groundwater may reduce these rates to near zero. 5.3 Infiltration Testing Infiltration testing was conducted using an open test pit method. Test pit areas will need to be re- excavated and compacted prior to construction of structures that will be sensitive to settlement. Test locations were presoaked prior to testing. Pre-soaking increases soil moistures, which allows the tested soils to reach a saturated condition more readily during testing. Saturation of the tested soils is desirable in order to isolate the vertical component of infiltration by inhibiting horizontal seepage during testing. Atlas No, B210474g Page 16 Copyright©2021 Atlas Technical Consultants Testing was conducted on February 26, 2021. Details and results of testing are as follows: Table 3—Infiltration Test Results Test Test Depth Stabilized Infiltration Design Infiltration Soil Type Rate Rate Location (feet bgs) (inches/hour) (inches per hour) TP-1 7.6 Poorly Graded Gravel >12.0 8.0 with Sand TP-2 6.0 Sandy Silt 4.8 2.40 Appropriate factors of safety have been applied to the stabilized infiltration rates achieved during testing to obtain the design infiltration rates listed above. The reason for the decreased infiltration rate is to account for long term saturation of the soils and the potential for less permeable soils to settle into the bottom of the infiltration facilities. Atlas recommends that all infiltration facilities be constructed in accordance with the local municipality requirements. 6. 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. Allowable settlement is usually exceeded before bearing capacity considerations become important; 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: Atlas No. 6210474g Page J 7 Copyright©2021 Atlas Technical Consultants T � � Table 4—Soil Bearing Capacity Footing Depth ASTM D1557 Net Allowable Soil Subgrade Compaction Bearing Capacity Footings must bear on competent, undisturbed, 1,500lbs/ft2 native lean clay soils, sandy silt soils, poorly graded gravel with sand sediments, or compacted structural Not Required for Native A'/3 increase is allowable fill. Existing organic materials must be completely Soil for short-term loading, removed from below foundation elements. o which is defined by Excavation depths ranging from roughly 0.5 to 2.2 95/o for Structural Fill seismic events or feet bgs should be anticipated to expose proper bearing soils.2 designed wind speeds. Footings must bear on competent, undisturbed, native sandy silt soils, poorly graded gravel with sand sediments, or compacted structural fill. Not Required for Native Existing organic materials and lean clay soils must Soil 2,000 Ibs/ft2 be completely removed from below foundation elements.' Excavation depths ranging from roughly 95%for Structural Fill 2.0 to 3.0 feet bgs should be anticipated to expose proper bearing soils.2 'It will be required for Atlas personnel to verify the bearing soil suitability for each structure at the time of construction. 2Depending 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 and sandy silt soils and 2)0.45 for footings bearing on native poorly graded gravel with sand sediments and granular structural fill. A passive lateral earth pressure of 297 pounds per square foot per foot(psf/ft) should be used for lean clay soils. For sandy silt soils, a passive lateral earth pressure of 337 psf/ft should be used. For native poorly graded gravel with sand sediments and 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 2018 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. Excessively loose or soft areas that are encountered in the footings subgrade will require over-excavation 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 24 inches below finished grade. Atlas No. B210474g Page 18 Copyright©2021 Atlas Technical Consultants 6.2 Crawl Space Recommendations All residences constructed with crawl spaces should be designed in a manner that will inhibit water in the crawl spaces. Bottom of crawl spaces must be elevated at least 2 feet above seasonal high groundwater elevation. Atlas recommends that roof drains carry stormwater at least 10 feet away from each residence. Grades should be at least 5 percent for a distance of 10 feet away from all residences. In addition, rain gutters should be placed around all sides of residences, and backfill around stem walls should be placed and compacted in a controlled manner. 6.3 Floor Slab-on-Grade 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 %-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 302.1 R and ASTM E1745 publications. Upon request, Atlas can provide further consultation regarding installation. 7. PAVEMENT DISCUSSION AND RECOMMENDATIONS Atlas has 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 3 has been assumed for near-surface lean 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. Atlas No. B210474g Page 19 Copyright©2021 Atlas Technical Consultants -�rk-r-C-A131. 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 5—AASHTO Flexible Pavement Specifications Pavement Section Component Driveways and Parking Driveways and Parking Light Duty Heavy Duty Asphaltic Concrete 2.5 Inches 3.0 Inches Crushed Aggregate Base 4.0 Inches 4.0 Inches Structural Subbase 12.0 Inches 14.0 Inches Compacted Subgrade Not Required Not Required '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 2/3 the component thickness. Gradation and suitability requirements shall be per ISPWC Section 801, Table 1. 7.2 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. Sub-grade 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. Atlas No. 6210474g Page 110 Copyright©2021 Atlas Technical Consultants 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 12-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 soils, sandy silt soils, poorly graded gravel with sand sediments, 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. Grasses with associated root systems were noted at the time of our investigation. 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. Stripping depths should be adjusted in the field to assure that the entire root zone or disturbed zone 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 No B210474g Page 1 11 Copyright©2021 Atlas Technical Consultants 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: • Track-mounted vehicles should be used to strip the subgrade of root matter and other deleterious 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. Atlas No. B210474g Page 112 Copyright©2021 Atlas Technical Consultants FA e Construction roadways on soft subgrade soils should consist of a minimum 2-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, 2-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 2 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 D2487). 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. If silty soil is used for structural fill, lift thicknesses should not exceed 6 inches (loose), and fill material moisture must be closely monitored at both the working elevation and the elevations of materials already placed. Following placement, silty soils must be protected from degradation resulting from construction traffic or subsequent construction. Atlas No. B210474g Page 1 13 Copyright©2021 Atlas Technical Consultants 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%-inch)material and no more than 12 percent fines(passing No. 200 sieve). These fill materials should be placed in layers not to exceed 12 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 92 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'/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 2.5 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 2.5 feet in height shall be backfilled in a manner that will limit the potential for damage from compaction methods and/or equipment. It is recommended that only small hand-operated compaction equipment be used for compaction of backfill 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. Atlas No B210474g Page 114 Copyright©2021 Atlas Technical Consultants �r'lrI L. IT�-- 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 1926, 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 (1'h:1)for excavations up to 20 feet in height. Excavations in excess of 20 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 native granular sediments from test pit sidewalls was observed, particularly after penetration of the water table. 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 Groundwater was encountered during the investigation but is anticipated to be below the depth of most construction. Excavations below the water table will require a dewatering program. Dewatering will be required prior to placement of fill materials. Placement of concrete can be accomplished through water by the use of a treme. 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 B210474g Page 1 15 Copyright c:,2021 Atlas Technical Consultants IL 9. GENERAL COMMENTS Based 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 B210474g Page 116 Copyright©2021 Atlas Technical Consultants 10. REFERENCES American 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) (2015). Guide for Concrete Floor and Slab Construction: ACI 302.1 R. Farmington Hills, MI:ACI. American Society of Civil Engineers (2021). ASCE 7 Hazards Tool: Web Interface [Online] Available: <https:Hasce7hazardtool.online/>(2021). American Society of Civil Engineers (ASCE) (2013). Minimum Design Loads for Buildings and Other Structures:ASCE/SEI 7-16. Reston,VA:ASCE. American Society for Testing and Materials(ASTM)(2017). Standard Test Method for Materials Finer than 75-um(No. 200)Sieve in Mineral Aggregates by Washing:ASTM C117.West Conshohocken, PA: ASTM. American Society for Testing and Materials (ASTM) (2014). Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates:ASTM C136.West Conshohocken, PA:ASTM. American Society for Testing and Materials (ASTM) (2012). 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) (2012). Standard Test Methods for Laboratory Compaction Characteristics of Soil Usinq Modified Effort:ASTM D1557.West Conshohocken, PA:ASTM. American Society for Testing and Materials (ASTM)(2014). Standard Test Methods for California Bearing Ratio:ASTM D1883.West Conshohocken, PA:ASTM. American Society for Testing and Materials(ASTM)(2017). Standard Practice for Classification of Soils for Engineering Purposes(Unified Soil Classification System):ASTM D2487.West Conshohocken,PA:ASTM. American Society for Testing and Materials(ASTM)(2017). 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)(2011). 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/> (2021). International Building Code Council (2018). International Building Code, 2018. Country Club Hills, IL: Author. Local Highway Technical Assistance Council (LHTAC) (2017). Idaho Standards for Public Works Construction, 2017. 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. Atlas No. 13210474g Page 1 17 Copyright©2021 Atlas Technical Consultants �T T I U.S. Department of Labor, Occupational Safety and Health Administration. CFR 29, Part 1926, Subpart P: Safety and Health Regulations for Construction. Excavations (1986). [Online]Available: <www.osha.gov> (2021). Atlas No. B210474g Page 118 Copyright©2021 Atlas Technical Consultants �r own � it e LN IT -- 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. B210474g Page 1 19 Copyright©2021 Atlas Technical Consultants professionals or contractors. Locations of exploratory sites referenced within this report should be considered 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. B210474g Page120 Copyright©2021 Atlas Technical Consultants �E ; ■ � } ■ �I NON $n 3A 3 V I N J su k . . � � v n �. ■ ■ � K � � J . m ME` .mN.D JIF r . § m � K ■� q � f e ■ n � v � o o � g in G %P) E G z E2 m } G � 2k aC', 2 Kc 2 \ k m a 0 §77 \ M � \ cn ) 0 gym § CD ® m o a . / CD J � - e E CLc i ■_� ]cr s 0 B §m c CD ■ � I 1 I I I I I I I I I I I I I I I 1 I I I I I I I I 1 I I I I I I I I I I I I l l l I ®W I I I I 1 1 1 1 I I I I I I I I I i I I I I I I I I I I I I I 1 I I I I I I I I I I I I I I W I I I I I I I I I I I I I T1 I I I I I -- - Z7 m D IIII ' I I 1 I O I I vl l i i l I I I I I I i 1 I I I I I I I I I 1 I ic cu I I I I I I I I I C I I I I I I C7 I I I 1 I cf) I 1 I I I I I I O I I I I I 1 m I I I I I I D I I I I I I I 1 Z I I I I 1 i C I I 1 m I I I I I I I I 1 I I I I I I I I I I I I I I I I I I II1 3NV1 318VN3A -------- I I I I I 1 I I I I I I I I I I I I 1 I I 1 I I I I I I I I 1 I I I I I I I I I I I I I I I I I I I I I I I I I Z I I I I I I I I ca N Dvli FEY moo s �v �� m oZO �. r G) _ -1 W 2 a srm c y a. x. Z 4mi V O (O Q N a o o m c� N 0 N d c A CL N co C cn CD `L w (D T O N N < ,1 V �\3 /n fV Appendix IV GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log#: TP-1 Latitude:43.634680 Date Advanced: February 25, 2021 Longitude: -116.404098 Excavated by: Turn of the Century Homes Depth to Water Table: 10.2 feet bgs Logged by: Bailey Hereford Total Depth: 11.4 feet bgs Depth Field Description and USCS Soil and Sample Sample Depth Qp Lab . •s) Sediment Classification Type bgs) Test ID Lean Clay (CL): Dark brown, slightly moist to 0.0-2.7 moist, medium stiff to stiff, with fine-grained GS 1.5-2.0 1.0-1.5 A sand. --Organics noted to 1.0 foot bgs. Sandy Silt(ML):Tan,dry to slightly moist,very 2 7-6 2 stiff to hard,with fine-grained sand. --Moderate calcic cementation encountered from 4.8 to 5.8 feet bgs. Poorly Graded Gravel with Sand (GP): Tan, 6.2-11.4 slightly moist to saturated, medium dense, with fine to coarse-grained sand,fine to coarse gravel, and 8-inch minus cobbles. Notes:See Site Map for test pit location. Piezometer installed to a depth of 11.4 feet bgs. Infiltration testing conducted at a depth of 7.6 feet bgs. Lab Test ID Moisture LL Pi Sieve Analysis (% Passing) 1 #40 #100 #200 A 23.2 38 16 100 1 100 98 94 89.7 Atlas No 13210474g Page 123 Copyright O 2021 Atlas Technical Consultants �l T � Te1 GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log#: TP-2 Latitude: 43.635473 Date Advanced: February 25, 2021 Longitude: -116.405078 Excavated by: Turn of the Century Homes Depth to Water Table: 10.0 feet bgs Logged by: Bailey Hereford Total Depth: 11.5 feet bgs Depth Field Description and USCS Soil and Sample Sample Depth Qp Lab ..$) Sediment Classificationbgs) Test ID Lean Clay (CL): Dark brown, slightly moist to 0.0-2.0 moist, stiff,with fine-grained sand. 1.5 --Organics noted to 0.5 foot bgs. Sandy Silt (ML): Tan, slightly moist, very stiff 2.0-6.2 to hard, with fine-grained sand. --Moderate calcic cementation encountered from 4.5 to 6.2 feet bgs. Poorly Graded Gravel with Sand (GP): Tan to 6.2-11.5 red-brown,slightly moist to saturated, medium dense, with fine to coarse-grained sand, fine to coarse gravel, and 6-inch minus cobbles. Notes:See Site Map for test pit location. Piezometer installed to a depth of 11.5 feet bgs. Infiltration testing conducted at a depth of 6.0 feet bgs. Atlas No, 13210474g Page 124 Copyright 6 2021 Atlas Technical Consultants GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log#: TP-3 Latitude:43.634711 Date Advanced: February 25, 2021 Longitude: -116.406157 Excavated by: Turn of the Century Homes Depth to Water Table: 9.2 feet bgs Logged by: Bailey Hereford Total Depth: 10.5 feet bgs DepthDepth Field Description and USCS Soil and Sample Sample .. bgs) Test ID Lean Clay (CL): Dark brown, slightly moist to 0.0-2.2 moist, stiff to very stiff,with fine-grained sand. 1.5-2.0 --Organics noted throughout. 2 2 5 2 Sandy Silt (ML): Tan, slightly moist, very stiff, with fine-grained sand. Poorly Graded Gravel with Sand (GP): Tan to 5.2-10.5 red-brown, slightly moist to saturated, medium dense, with fine to coarse-grained sand, fine Ito coarse gravel, and 6-inch minus cobbles. Notes:See Site Map for test pit location. Piezometer installed to a depth of 10.5 feet bgs. Atlas No. 13210474g Page 125 Copyright 2021 Atlas Technical Consultants 1�T-c-P�1. GEOTECHNICAL INVESTIGATION TEST PIT LOG Test Pit Log#: TP-4 Latitude:43.634153 Date Advanced: February 25, 2021 Longitude: -116.405144 Excavated by: Turn of the Century Homes Depth to Water Table: 8.2 feet bgs Logged by: Bailey Hereford Total Depth: 8.7 feet bgs Depth Field Description and USCS Soil and Sample Sample Depth Qp Lab •.$) Sediment Classification Typebgs) Test ID Lean Clay (CL): Dark brown, slightly moist to 0.0-3.0 moist, medium stiff to very stiff, with fine- 1.0-2.0 grained sand. --Organics noted to 1.5 feet bgs. Poorly Graded Gravel with Sand(GP): Brown, 3.0-8.7 slightly moist to saturated, medium dense, with fine to coarse-grained sand,fine to coarse gravel, and 8-inch minus cobbles. Notes:See Site Map for test pit location. Piezometer installed to a depth of 8.7 feet bgs. Atlas No. 6210474g Page 126 Copyright C,2021 Atlas Technical Consultants Appendix V GEOTECHNICAL GENERAL NOTES Unified Soil Classification System Major Divisions S mbol Soil Descri tions Gravel & GW Well- raded ravels; ravel/sand mixtures with little or no fines Coarse- Gravelly Soils GP Poorly-graded ravels; ravel/sand mixtures with little or no fines Grained <50% GM Silty gravels; poorly-graded ravel/sand/silt mixtures Soils< coarse GC Clayey gravels; poorly-graded gravel/sand/clay mixtures 50% Sand&Sandy SW Well-graded sands;gravelly sands with little or no fines passes Soils>50% SP Poorly-graded sands;gravelly sands with little or no fines No.200 coarse SM Silty sands; poorly-graded sand/gravel/silt mixtures sieve fraction Sc Clayey sands; poorly-graded sand/gravel/clay mixtures Fine- ML Inorganic silts; sandy, gravelly or clayey silts Grained Silts&Clays CL Lean clays; inorganic, gravelly, sandy,or silty, low to medium- Soils> LL<50 lasticit cla s 50% OL Organic, low-plasticity clays and silts passes MH Inor anic,elastic silts; sandy, ravel) or clayey elastic silts No.200 Silts&Clays CH Fat clays; high-plasticity, inorganic clays sieve LL>50 OH Organic, medium to high-plasticity clays and silts Highly Organic Soils PT Peat, humus, h dric soils with high organic content Relative Density and Consistency Moisture Content and Cementation Classification Classification Coarse-Grained Soils SPT Blow Counts N Description Field Test Very Loose: <4 Dry Absence of moisture, dry to touch Loose: 4-10 Slightly Moist Damp, but no visible moisture Medium Dense: 10-30 Moist Visible moisture Dense: 30-50 Wet Visible free water Very Dense: I >50 Saturated Soil is usually below water table Fine-Grained Soils SPT Blow Counts N Description Field Test Very Soft: <2 Weak Crumbles or breaks with handling or Soft: 2-4 slight finger pressure Medium Stiff: 4-8 Moderate Crumbles or breaks with Stiff: 8-15 considerable finger pressure Very Stiff: 15-30 Strong Will not crumble or break with finger Hard: >30 pressure Particle Size Acronym List Boulders: > 12 in. GS grab sample Cobbles: 12 to 3 in. LL Liquid Limit Gravel: 3 in.to 5 mm M moisture content Coarse-Grained Sand: 5 to 0.6 mm NP non-plastic Medium-Grained Sand: 0.6 to 0.2 mm PI Plasticity Index Fine-Grained Sand: 0.2 to 0.075 mm Qp penetrometer value, unconfined compressive Silts: 0.075 to 0.005 strength,tsf mm Clays: <0.005 mm V vane value, ultimate shearing strength, tsf Atlas No B210474g Page 127 Copyright©2021 Atlas Technical Consultants .�1A le Appendix Appendix VI AASHTO PAVEMENT DESIGN Pavement Section Design Location:Proposed Mixed-Use Development,Light Duty Average Daily Traffic Count: 250 All Lanes&Both Directions Design Life: 20 Years Percent of Traffic in Design Lane: 501% Terminal Seviceability Index(Pt): 2.5 Level of Reliability: 95 Subgrade CBR Value: 3 Subgrade Mr: 4,500 Calculation of Design•18 kip ESALs Daily Growth Load Design Traffic Rate Factors ESALs Passenger Cars: 112 2.0% 0.0008 795 Buses: 0 2.0% 0.6806 0 Panel&Pickup Trucks: 10 2.0% 0.0122 1,082 2-Axle,6-Tire Trucks: 2 2.0% 0.1890 3,352 Emergency Vehicles: 1.0 2.0% 4.4800 39,731 Dump Trucks: 0 2.0% 3.6300 0 Tractor Semi Trailer Trucks: 0 2.0% 2.3719 0 Double Trailer Trucks 0 2.0% 2.3187 0 Heavy Tractor Trailer Combo Trucks: 0 2.0% 2.9760 0 Average Daily Traffic in Design Lane: 125 Total Design Life 18-kip ESALs: 44,960 Actual Log(ESALs): 4.653 Trial SN: 2.70 Trial Log(ESALs): 4.660 Pavement Section Design SN: 2.81 Design Depth Structural Drainage Inches Coefficient Coefficient Asphaltic Concrete: 2.50 042 n/a Asphalt-Treated Base: 0.00 0.25 n/a Cement-Treated Base: 0.00 0-17 n/a Crushed Aggregate Base: 4.00 014 1.0 Subbase: 12.00 0.10 1.0 Special Aggregate Subgrade: 0.00 0.09 0.9 Atlas No. B210474g Page 128 Copyright-; 2021 Atlas Technical Consultants T � AASHTO PAVEMENT DESIGN Pavement Section Design Location:Proposed Mixed-Use De%elopment,Heavy Duty Average Daily Traffic Count: 250 All Lanes&Both Directions Design Life: 20 Years Percent of Traffic in Design Lane: 50% Terminal Seviceability Index(Pt): 2.5 Level of Reliability: 95 Subgrade CBR Value: 3 Subgrade Mr: 4,500 Calculation of Design-18 kip ESALs Daily Growth Load Design Traffic Rate Factors ESALs Passenger Cars: 95 2.0% 0.0008 674 Buses: 2 2.0% 0.6806 12,072 Panel&Pickup Trucks: 15 2.0% 00122 1,623 2-Axle,6-Tire Trucks: 10 2.0% 0.1890 16,762 Emergency Vehicles: 1.0 2.0% 4.4800 39,731 Dump Trucks: 1 2.0% 3.6300 32,193 Tractor Semi Trailer Trucks: 1 2.0% 2.3719 21,035 Double Trailer Trucks 0 2.0% 2.3187 0 Heavy Tractor Trailer Combo Trucks: 0 2.0% 2.9760 0 Average Daily Traffic in Design Lane: 125 Total Design Life 18-kip ESALs: 124,089 Actual Log(ESALs): 5.094 Trial SN: 3.20 Trial Log(ESALs): 5.105 Pavement Section Design SN: 3.22 Design Depth Structural Drainage Inches Coefficient Coefficient Asphaltic Concrete: 3.00 0.42 n/a Asphalt-Treated Base: 0.00 0.25 n/a Cement-Treated Base: 0.00 0.17 n/a Crushed Aggregate Base: 4.00 0.14 1.0 Subbase: 14.00 0.10 1.0 Special Aggregate Subgrade: 0.00 009 0.9 Atlas No. B210474g Page 129 Copyright©2021 Atlas Technical Consultants IMPOPIOnt InfoPmation about Geolechnicol-Engineeping . . . . . . . . . disputes. While . . . information is The Geoprofessional Business Association(GBA) will not likely meet the needs of a civil-works constructor or even a has prepared this advisory to help you—assumedly different civil engineer.Because each geotechnical-engineering study a client representative—interpret and apply this is unique,each geotechnical-engineering report is unique,prepared geotechnical-engineering report as effectively as solely for the client. possible. In that way,you can benefit from a lowered Likewise,geotechnical-engineering services are performed for a specific exposure to problems associated with subsurface project and purpose.For example,it is unlikely that a geotechnical conditions at project sites and development of engineering study for a refrigerated warehouse will be the same as them that,for decades, have been a principal cause one prepared for a parking garage;and a few borings drilled during of construction delays,cost overruns, claims, a preliminary study to evaluate site feasibility will not be adequate to and disputes.If you have questions or want more develop geotechnical design recommendations for the project. information about any of the issues discussed herein, contact your GBA-member geotechnical engineer. Do not rely on this report if your geotechnical engineer prepared it: Active engagement in GBA exposes geotechnical • for a different client; engineers to a wide array of risk-confrontation • for a different project or purpose; techniques that can be of genuine benefit for • for a different site(that may or may not include all or a portion of everyone involved with a construction project. the original site);or before important events occurred at the site or adjacent to it; e.g.,man-made events like construction or environmental Understand the Geotechnical-Engineering Services remediation,or natural events like floods,droughts,earthquakes, Provided for this Report or groundwater fluctuations. Geotechnical-engineering services typically include the planning, collection,interpretation,and analysis of exploratory data from Note,too,the reliability of a geotechnical-engineering report can widely spaced borings and/or test pits.Field data are combined be affected by the passage of time,because of factors like changed with results from laboratory tests of soil and rock samples obtained subsurface conditions;new or modified codes,standards,or from field exploration(if applicable),observations made during site regulations;or new techniques or tools.If you are the least bit uncertain reconnaissance,and historical information to form one or more models about the continued reliability of this report,contact your geotechnical of the expected subsurface conditions beneath the site.Local geology engineer before applying the recommendations in it.A minor amount and alterations of the site surface and subsurface by previous and of additional testing or analysis after the passage of time-if any is proposed construction are also important considerations.Geotechnical required at all-could prevent major problems. engineers apply their engineering training,experience,and judgment to adapt the requirements of the prospective project to the subsurface Read this Report in Full model(s). Estimates are made of the subsurface conditions that Costly problems have occurred because those relying on a geotechnical will likely be exposed during construction as well as the expected engineering report did not read the report in its entirety.Do not rely on performance of foundations and other structures being planned and/or an executive summary.Do not read selective elements only.Read and affected by construction activities. refer to the report in full. The culmination of these geotechnical-engineering services is typically a You Need to Inform Your Geotechnical Engineer geotechnical-engineering report providing the data obtained,a discussion About Change of the subsurface model(s),the engineering and geologic engineering Your geotechnical engineer considered unique,project-specific factors assessments and analyses made,and the recommendations developed when developing the scope of study behind this report and developing to satisfy the given requirements of the project.These reports may be the confirmation-dependent recommendations the report conveys. titled investigations,explorations,studies,assessments,or evaluations. Typical changes that could erode the reliability of this report include Regardless of the title used,the geotechnical engineering report is an those that affect: engineering interpretation of the subsurface conditions within the context - the site's size or shape; of the project and does not represent a close examination,systematic . the elevation,configuration,location,orientation, inquiry,or thorough investigation of all site and subsurface conditions. function or weight of the proposed structure and Geotechnical-Engineering Services are Performed the desired performance criteria; for Specific Purposes, Persons,and Projects, • the composition of the design team;or and At Specific Times • project ownership. Geotechnical engineers structure their services to meet the specific As a general rule,always inform your geotechnical engineer of project needs,goals,and risk management preferences of their clients.A or site changes even minor ones and request an assessment of their geotechnical-engineering study conducted for a given civil engineer impact.The geotechnical engineer who prepared this report cannot accept responsibility or liability for problems that arise because the geotechnical conspicuously that you've included the material for information purposes engineer was not informed about developments the engineer otherwise only.To avoid misunderstanding,you may also want to note that would have considered. "informational purposes"means constructors have no right to rely on the interpretations,opinions,conclusions,or recommendations in the Most of the"Findings" Related in This Report report.Be certain that constructors know they may learn about specific Are Professional Opinions project requirements,including options selected from the report,only Before construction begins,geotechnical engineers explore a site's from the design drawings and specifications.Remind constructors subsurface using various sampling and testing procedures.Geotechnical that they may perform their own studies if they want to,and be sure to engineers can observe actual subsurface conditions only at those specific allow enough time to permit them to do so.Only then might you be in locations where sampling and testing is performed.The data derived from a position to give constructors the information available to you,while that sampling and testing were reviewed by your geotechnical engineer, requiring them to at least share some of the financial responsibilities who then applied professional judgement to form opinions about stemming from unanticipated conditions.Conducting prebid and subsurface conditions throughout the site.Actual sitewide-subsurface preconstruction conferences can also be valuable in this respect. conditions may differ maybe significantly-from those indicated in this report.Confront that risk by retaining your geotechnical engineer Read Responsibility Provisions Closely to serve on the design team through project completion to obtain Some client representatives,design professionals,and constructors do informed guidance quickly,whenever needed. not realize that geotechnical engineering is far less exact than other engineering disciplines.This happens in part because soil and rock on This Report's Recommendations Are project sites are typically heterogeneous and not manufactured materials Confirmation-Dependent with well-defined engineering properties like steel and concrete.That The recommendations included in this report-including any options or lack of understanding has nurtured unrealistic expectations that have alternatives-are confirmation-dependent.In other words,they are not resulted in disappointments,delays,cost overruns,claims,and disputes. final,because the geotechnical engineer who developed them relied heavily To confront that risk,geotechnical engineers commonly include on judgement and opinion to do so.Your geotechnical engineer can finalize explanatory provisions in their reports.Sometimes labeled"limitations;' the recommendations only after observing actual subsurface conditions many of these provisions indicate where geotechnical engineers' exposed during construction.If through observation your geotechnical responsibilities begin and end,to help others recognize their own engineer confirms that the conditions assumed to exist actually do exist, responsibilities and risks.Read these provisions closely.Ask questions. the recommendations can be relied upon,assuming no other changes have Your geotechnical engineer should respond fully and frankly. occurred.Thegeotechnical engineer who prepared this report cannot assume responsibility orliabilityfor confirmation-dependent recommendations ifyou Geoenvironmental Concerns Are Not Covered fail to retain that engineer to perform construction observation. The personnel,equipment,and techniques used to perform an environmental study-e.g.,a"phase-one'or"phase-two'environmental This Report Could Be Misinterpreted site assessment-differ significantly from those used to perform a Other design professionals'misinterpretation of geotechnical- geotechnical-engineering study.For that reason,a geotechnical-engineering engineering reports has resulted in costly problems.Confront that risk report does not usually provide environmental findings,conclusions,or by having your geotechnical engineer serve as a continuing member of recommendations;e.g.,about the likelihood of encountering underground the design team,to: storage tanks or regulated contaminants.Unanticipated subsurface • confer with other design-team members; environmental problems have led to project failures.If you have not • help develop specifications; obtained your own environmental information about the project site, • review pertinent elements of other design professionals'plans and ask your geotechnical consultant for a recommendation on how to find specifications;and environmental risk-management guidance. • be available whenever geotechnical-engineering guidance is needed. Obtain Professional Assistance to Deal with You should also confront the risk of constructors misinterpreting this Moisture Infiltration and Mold report.Do so by retaining your geotechnical engineer to participate in While your geotechnical engineer may have addressed groundwater, prebid and preconstruction conferences and to perform construction- water infiltration,or similar issues in this report,the engineer's phase observations. services were not designed,conducted,or intended to prevent migration of moisture-including water vapor-from the soil Give Constructors a Complete Report and Guidance through building slabs and walls and into the building interior,where Some owners and design professionals mistakenly believe they can shift it can cause mold growth and material-performance deficiencies. unanticipated-subsurface-conditions liability to constructors by limiting Accordingly,proper implementation of the geotechnical engineer's the information they provide for bid preparation.To help prevent recommendations will not of itself be sufficient to prevent the costly,contentious problems this practice has caused,include the moisture infiltration.Confront the risk of moisture infiltration by complete geotechnical-engineering report,along with any attachments including building-envelope or mold specialists on the design team. or appendices,with your contract documents,but be certain to note Geotechnical engineers are not building-envelope or mold specialists. GEOPROFESSIONAL BUSINESS - ASSOCIATION Telephone:301/565-2733 e-mail:info@geoprofessional.org www.geoprofessional.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 GBAs 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. � AO NATURAL -RESOURCE L�� LLCMIKE RAYMOND Consulting, Soil Evaluations & Data Collection _ Phone: 208.409-1505 Email:mraydirty@gmail.com November 14, 2022 Mr. Jon Wardle Brighton Corporation 2929 W. Navigator Drive Suite 400 Meridian, ID 83642 We have completed monitoring of ground water levels for the 2022 season for the Ustick-Venable project. Included with this report are copies of all data recorded to date along with a data summary, supporting graphics, and a map of the site for reference. This property is located about 2.5 miles south of the Boise River on a bisected terrace at an elevation of approximately 2575 feet. It is well above the river's flood plain. The South Slough runs about 0.4 miles south of the property, and there is an unnamed irrigation lateral about 0.4 miles to the north. The site is surrounded by residential and public development, with some areas of abandoned farmland. Precipitation in calendar year 2022 was 82 percent of normal for the area through September. All piezometers held ground water when monitoring began in March. The piezometer at TP2-21 was subsequently dry to 134 inches (11.2 feet) below ground surface (bgs) from April 6 through May 4. Piezometer TP 1-21 was destroyed by earthwork on the property prior to the August 25 reading. Ground water at piezometer TP4-21 was closest to the surface throughout 2022 averaging 78 inches (6.5 feet) bgs for the season. The greatest average depth to ground water occurred at location TP1-21 (125 inches/10.4 feet bgs). Ground water rose steadily once irrigation water was introduced to the area in April. Ground water at TP4-21 reached 57 inches (4.8 feet) bgs by the final reading on October 5. This was closer to the surface than any of the other piezometers, and is closer to the surface than all other levels recorded at all locations during 2021 as well. Ground water in the piezometers at TP2-21 and TP3-21 also reached its highest levels late in the season. Although ground water levels were static or still rising at TP2-21, TP3-21, and TP4-21 through the final reading, it is likely that ground water levels fell shortly thereafter as the effects of irrigation dissipated. 5740 N. APPLEBRooK WAY BoisE,IDAHO 83713 Ustick-Venable 2022 final groundwater report page 2 A review of data collected in 2021 was also completed. The rise of ground water was steeper in 2022 than 2021, and receding ground water levels late in the season were more obvious in 2021. The following pages include graphic display of data for both years for comparison, along with a data summary. If there are any questions, please contact me by phone or email. Thank you. transmitted via e-mail MICHAEL A. RAYMOND, M.S. Soil Scientist cc: Daniel Frisby, Brighton Corp., Meridian, ID 2022 Ustick-Venable Project Ground Water Monitoring Date of Measurement Piezometer Bottom 3/10 416 1 4/19 1 5/4 1 5/18 1 6/2 1 6/16 1 6/29 1 7/15 1 7/27 1 8/10 1 8/25 1 917 1 9/18 1 10/5 Location Depth --------------------------------------------------- depth (inches) to ground water--------------------------------------------------- TP1-21 143 132 134 136 134 129 126 121 118 117 117 113 DEST DEST DEST DEST TP2-21 134 130 134+ 134+ 134+ 130 128 121 115 114 111 108 105 101 101 101 TP3-21 122 108 111 112 112 104 99 93 90 89 86 85 81 79 79 79 TP4-21 135 88 96 94 93 88 83 78 74 72 73 71 69 67 66 57 Note: Values highlighted in yellow are the levels closest to the surface and are recorded as seasonal peaks. Values in red followed by "+" represent a piezometer dry to the bottom depth shown. DEST Indicates the piezometer was destroyed prior to the date shown. 2022 Ustick-Venable Project Depth (inches) To Ground Water With Time 3/1 4/1 5/1 6/1 7/1 8/1 9/1 10/1 11/1 50 60 70 80 90 ---- 100 ------------------------------ -------------------------------------------- 110 ----------- ---------------------------- - 120 130 -- ----------------- 140 ---------- --*--TP1-21 •-w •TP2-21 (dry) TP2-21 --o—TP3-21 --o—TP4-21 Note: Dotted lines w/open symbols represent a dry piezometer. Solid lines/symbols represent a piezometer holding ground water. Piezometer TP1-21 was destroyed prior to the August 25 reading. Ustick/Venable 2021 and 2022 Ground Water Monitoring Data Summary 2022 2021 Piezometer Average Depth Peak Rise Average Depth Peak Rise Location in. bgs ft. bgs in. bgs ft. bgs date in. ft. in. bgs ft. bgs in. bgs ft. bgs date in. ft. TP1-21* 125 10.4 113 9.4 8/10 23 1.9 112 9.3 102 8.5 9/9 20 1.7 TP2-21 118 9.8 101 8.4 9/7-10/5 33 109 9.1 100 8.3 8/26-9/9 21 1.8 TP3-21 94 7.8 79 6.6 9/7-10/5 33 2.8 86 7.2 78 6.5 8/26-9/9 21 1.8 TP4-21 78 6.5 57 4.8 10/5 39 3.3 73 6.1 63 5.3 8/26 31 2.6 Average 104 8.7 88 7.3 1 9/14 32 2.7 95 7.9 86 7.2 9/2 23 1.9 Note: Values hilighted in yellow are the average depth and peak closest to ground surface and the maximum rise over both years. Values in red were calculated using the bottom depth for dry piezometers. *The piezometer at TP1-21 was destroyed prior to the August 25 reading in 2022. 2021 Ustick Venable Ground Water Monitoring 2021 Date of Measurement Piezometer Bottom 3/10 1 4/10 1 4/22 1 5/8 1 5/26 1 6/4 1 6/17 6/29 1 7/15 1 7/30 1 8/12 1 8/26 1 9/9 1 9/23 1 10/6 Location Depth ------------------------------------------------------ depth (inches) to ground water ------------------------------------------------------- TP1-21 143 115 121 122 121 116 115 112 112 109 107 105 103 102 106 112 TP2-21 134 113 119 121 118 114 110 108 108 105 105 102 100 100 104 109 TP3-21 122 90 85 99 96 90 89 85 84 85 82 79 78 78 82 89 TP4-21 135 75 94 83 82 77 76 71 71 70 69 66 63 65 65 73 Note: Values hilighted in yellow are seasonal peaks. 2021 Ustick Venable Depth (inches) To Ground Water With Time 3/1 4/1 5/1 6/1 7/1 8/1 9/1 10/1 11/1 50 60 70 80 90 -- ------------- ------------------------------------------------------ 100 --- ------------------ 110 -------------------------- ---------- 120 ---------- -- -- --- ----------------------------------------------------------- 130 ------------------------------------------------------------------------------------ 140 tTP1-21 -*--TP2-21 fTP3-21 tTP4-21 Ustick-Venable Project a--� Legend Q Piezometer Location Map Piezometer� � o �— • 1-l y � 29 I Aw- o. Pt Y �u u h o - A&LFPO Cul . . 3 ' '• - ..- o 11