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CC - Storm Drainage Calcs THE LAND GROUP Chukar Ridge Subdivision 4005 N. McDermott Road, Meridian, ID Storm Drain Management & Engineering Drainage Report Developer Investment Analytic Group, LLC Engineer The Land Group, Inc. 462 East Shore Drive, Suite 100 ��lON T E� G Eagle, Idaho 83616 c� G�S Contact: Jason Densmer, PE Ph: 208.939.4041 109 1 ATE 0� TLG Project No. 119192 fq F ` ND 11/09/2020 462 East Shore Drive, Suite 100, Eagle, Idaho 83616 208.939.4041 thelandgroupinc.com Chukar Ridge Subdivision Meridian, ID Storm Water Management Report Site Description & Report Purpose The Chukar Ridge Subdivision is located at the west McDermott Road in Meridian ID. The project is a subdivision consisting of single-family residential lots. This report analyzes the proposed storm drain facilities to be constructed by the project and confirms the adequacy of these systems to serve the needs of the project. Construction documents of the improvements have been prepared and show final details necessary for construction. Proposed Post-development Drainage Basins Appendix A provides an overview of the proposed drainage basins. The entire single family residential area consists of a single drainage basin. Improvements to the McDermott Road frontage comprise a small, secondary basin. On-Site Drainage System Description & Areas The project will develop a system of permeable pavers within the ACHD Right-of-way to collect and store storm water runoff. The permeable paver area will be constructed per ACHD's requirements and standards.Stormwater collected and retained in the system will infiltrate into the soils underlying the site. Off-Site Drainage System Description & Area The project will develop a drainage Swale along McDermott road to collect and store storm water runoff. The swale will be constructed per ACHD's requirements and standards.Stormwater collected and retained in the system will infiltrate into the soils underlying the site Developed Storm Volume The drainage systems have been designed in accordance with current ACHD policies and per their published design calculation spreadsheets. These use a 100-year design storm. The drainage calculations prepared using ACHD's spreadsheets are provided in Appendix B. The calculations presented in this report show that the proposed facilities are adequately sized to accommodate the expected storm water runoff from the site. 462 East Shore Drive, Suite 100, Eagle, Idaho 83616 208.939.4041 • thelandgroupinc.com Chukar Ridge Subdivision Meridian, ID Storm Water Management Report Appendix A Site Drainage Areas 462 East Shore Drive, Suite 100, Eagle, Idaho 83616 208.939.4041 thelandgroupinc.com THE LAND - GROUP ESN/ � \ Ew�� \� \\ \ �X� I I� I Ew x� I XIcc i \\ � X EG � EIA, \ \\ \\ \x�x_ I Imo+ EG \\\\ Ew� x E W� EG Eby i X \EG\E\\EGA\\\\ WEST LAZY DIAMOND C LANE i I D EG \\ \ Ew \ �. lFE ag x� \\_ \\_ ��E YD,a o w WI , IFG EG\\ EG�\ 4f c lane \ X�x\ I `� \\ EG ad X� Z: - G \\ den p x� \\ I I FACILITY / , \FG \ ra�nx� \ UJ w csl 1 / l / EG \\�G \\\\ �� X� \ X \ X�X I I m� L � - 31177 SF \\ \�Ew Driveway A M l l Ec\\\_EG _ Ew E� X�X I c c� EG w WI � EW X r — / EG \ \\ \\ \\ — +--X 8ss O FACILITY EG v� IM w wl � R �, / / \EG \\\\ \ \ f FACILITY ._,, 8„ 1 / / �EG�\,�\\� i m �; - R 44453 SF a \ �\\\ I I cz cs — b I EG — TI �� W L J J \ - I 12743 SF ��,,, �� ,, I � F 1 8'-ss � \ G y \ � I x LL \\ \ FACILITY _ i �1� \ Cc 1 FACILITY - — cc , \ I I x W w CD FACILITY a FACILITY 1 a IJ CZ 1 1 7477 SF I II x Q I I 29434 SF — — 0 I I� ' I I I � 28724 SF 14473 SF SWALE 1 I I I x �+ - - - Imo— FACILITY w WI — 1 6711 SF o a x p E ` 8W 17535 SF � I , I I I o I CD FACILITY 8"SS $ S I � 0- --------------- - �� oz _ � R/W , �, 1 � — � I I ----- II I Q °° — — FACILITY _ c� I x 1�+Fi z+nn g�W 14+00 W Achievement St I— 33720 P F ,� I I I � to s"SS I� 1 I� 00, I I i i i x CIO) w - - - - --------------- I I I 19810 SF 7 ICL � ' II I � x i IIRR I I Revisions 1 I IRR I I �lB X � 12". I 12"GIRR 12"GIRR 1. PI LEI P — LA 2'PIRR _X " IRR X 2"PIX I I I � I I cs - A _ CE 1/16 CORNER = SECTION 32 A = TAN., R.1W., B.M. o = N - A - O = M - Project No.: 119192 Date of Issuance: 10.28.2020 Project Milestone: AGENCY SUBMITTAL Exhibits Drainage Map ME =_� Draina a Ma 60' 120' �a g p Horizontal Scale: 1" = 60' EX 01 ��o Chukar Ridge Subdivision Meridian, ID Storm Water Management Report Appendix B Drainage Calculations 462 East Shore Drive, Suite 100, Eagle, Idaho 83616 208.939.4041 thelandgroupinc.com 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. rge Rate using th r post-developm 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 Chukar Ridge Subdivision 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) 5 Click to Show More Subbasins ❑ Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 Subbasin 6 7 8 9 30 5 Area of Drainage Subbasin(SF or Acres) SF 12,743 31,177 29,434 28,724 33,720 14,473 7,477 44,453 17,535 19,810 Acres S.SO 6 Determine the Weighted Runoff Coefficient(C) 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50 C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 0.50 7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 user Calculate min i0 Min. Estimated Runoff Coefficients for Various Surface Type of Surface Runoff Coefficients"I 8 Determine the average rainfall intensity(i)from IDF Curve based on Tc i 2.58 in/hr Business Downtown areas 0.70-0.95 9 Calculate the Post-Development peak discharge(ClPeak) QPeA 7.09 CfS Urban neighborhoods 0.50-0.70 Residential 10 Calculate total runoff vol(V)(for sizing primary storage) V 9,503 ft Single Family 0.35-0.50Multi-family 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 I(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) Vrr 5,939 W Heavy areas 0.90 12 Detention:Approved Discharge Rate to Surface Waters(if applicable) cfs 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 095 Basin Foreba V 950 ft' . Y Concrete 0.95 Primary Treatment/StorageBasin V 8,552 ft' Brick 0.95 Subsurface Storage Roofs 0.95 Gravel Volume Without Sediment Factor(See BMP 20 Tab) V 9,503 ft' Fields:Sandy soil Soil Soil Type Slope A B C D Flat:0-2% 0.04 0.07 0.11 0. Average:2-6% 0.09 0.12 0.15 0. Steep:>6% 0.13 0.18 0.23 0. Adapted from ASCE G:\2019\119192\CAD\Calcs and Reports\119192 ACHD_SD_CALCS pavers.xlsm 10/26/2020,7:16 AM Version 10.5,November 2018 ACHD Calculation Sheet for Permeable Interlocking Concrete Pavers (PICP) 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 Chukar Ridge Subdivision Runoff Calculations 1 Design Storm 100 Link to:LQ,V 2 Weighted Runoff Coefficient C 0.50 QV2 QV3 3 Area A(Acres) 5.50 acres QV4 4 Approved Discharge Rate(if applicable) 0.00 cfs QV5 Q,V TR55 5 Design Volume V 9,503 ft3 Paver&Aggregate Details 6 Enter Total Paver Area Length L 420.00 ft 7 Enter Total Paver Area Width W 29.00 ft 8 Total Paver Area A 12,180 ft2 9 Paver Joint Opening Area per Manf.Spec 0.10 Assume 0.10 10 Depth of Storage Stone 2.00 ft 11 Void Factor of Storage Stone(0.4 Max) 0.40 12 Available Storage in Paver Aggregate VAvaii 9,744 ft, 13 Does Aggregate Have Storage Capacity?Vavail V YES Infiltration 14 Subgrade Infiltration Rate From Soils Report 8.00 in/hr 15 Time to Infiltrate -hrs Aggregate in/hr 16 Joint Aggregate Infiltration Rate:#8 Stone 500 in/hr #8 Stone 500.00 Peak Discharge 17 Time of Concentration Tc 10 min 18 Peak Q QStorm 7.09 cfs 19 Capacity of Paver Joints QPeak_Pavers 14.10 cfs 20 oints Take Peak Flow? OK G:\2019\119192\CAD\Calcs and Reports\119192 ACHD_SD_CALCS pavers.xlsm 10/26/2020,7:17 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 Engineer's methodology must result in facilities that meet or exceed these calculations in order to be accepted. rge Rate using th r post-developm 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 Chukar Ridge Subdivision,Facility 5 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 Click to Show More Subbasins ❑ Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin 1 Subbasin 2 3 4 5 Subbasin 6 7 8 9 10 5 Area of Drainage Subbasin(SF or Acres) SF 6,711 Acres 0.15 6 Determine the Weighted Runoff Coefficient(C) 0.50 0.50 C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 0.50 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"I 8 Determine the average rainfall intensity(i)from IDF Curve based on Tc i 2.5F0.6Oin Business Downtown areas 0.70-0.95 9 Calculate the Post-Development peak discharge(QPeak) Qpe,k 2Urban neighborhoods 0.50-0.70 Residential Single Family 0.35-0.50 10 Calculate total runoff vol(V)(for sizing primary storage) Multi-family 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 I(95th percentile=0.60 in) 95Light areas 0.80 Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) Vrr 166 ft' Heavy areas 0.90 12 Detention:Approved Discharge Rate to Surface Waters(if applicable) 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 Basin Foreba V 27 ft` Asphalt 0.95 Y Concrete 0.95 Primary Treatment/StorageBasin V 240 ft' Brick 0.95 Subsurface Storage Roofs 0.95 Volume Without Sediment Factor(See BMP 20 Tab) V 266 ft' Gravel 0.75 Fields:Sandy soil Soil Type Slope A B C D Flat:0-2% 0.04 0.07 0.11 O. Average:2-6% 0.09 0.12 0.15 O. Steep:>6% 0.13 0.18 0.23 O. Adapted from ASCE G:\2019\119192\CAD\Calcs and Reports\119192 ACHD_SD_CALCS.xlsm 10/26/2020,7:20 AM Version 10.5,November 2018 ACHD Calculation Sheet for Sizing Bioswales & Borrow Ditches 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 Chukar Ridge Subdivision,Facility 5 2 Enter number of Bioswales/Borrow Ditches(25 max) 1 3 Design Storm 100 Weighted Runoff Coefficient C 0.50 Link to: Q,v 4 Area A(Acres) 0.15 acres Q,V2 QV3 Approved discharge rate for the given storm(if applicable) 0.00 cfs QV4 5 Design Vol With 0%Sed for Swales V 266 ft3 fQ,Vs 6 Length of Swale 251 ft 7 Infiltration Window?(Note:infiltration required if Longitudinal Slope<10%) Design Infiltration Rate 8.00 in/hr 8 Infiltration Window Width 0.75 ft 9 Set Swale Bottom Width b 0.75 ft 10 Set Swale Top Width 7.00 ft 11 Set Swale Depth y 0.50 ft 12 Swale Side Slopes H:1 Sxs 4.00 13 Calculate cross-sectional area Axs 1.38 ft' Axs=Y zz+by 14 Total Swale Capacity Without Driveways 345 ft3 15 Does it Have Capacity? OK 16 Time to Drain 2.1 hr 90%volume in 48-hours minimum OK Check Swale With Driveways 17 Avg.Driveway Fill Slope in Swale (H/V) ft/ft 18 Enter Total Number of Driveways ea 0.0 ft3 Deduct driveway slope 19 Enter Total Length of all Driveways ft 0.0 ft3 Deduct driveway length 20 Lost Swale Length From Trees,etc. ft 0.0 ft3 Deduct other 21 Adjusted Length of Infiltration Area 0.0 ft 22 Excess Capacity=Storage-Deductions-Runoff Volume (266.2) ft3 23 Is Capacity Good? 24 Time to Drain 0.0 hr 90%volume in 48-hours minimum OK G:\2019\119192\CAD\Calcs and Reports\119192 ACHD_SD_CALCS.xlsm 10/26/2020,7:21 AM Version 10.0,May 2018 Chukar Ridge Subdivision Meridian, ID Storm Water Management Report Appendix c Project Geotechnical Report 462 East Shore Drive, Suite 100, Eagle, Idaho 83616 208.939.4041 thelandgroupinc.com GEOTECHNICAL EVALUATION FOR "SPRIGGLE PARCEL SUBDIVISION" — AN 1 1.5+ ACRE RESIDENTIAL DEVELOPMENT LOCATED AT THE SOUTHWEST CORNER OF THE NORTH MCDERMOTT ROAD AND WEST LAZY DIAMOND C LANE INTERSECTION, MERIDIAN, IDAHO February 1 1, 2020 GTI-Project No. 2097-ID Prepared For: LASHER ENTERPRISES 3327 N Eagle Road Meridian, ID 83642 GeoTek, Inc. TABLE OF CONTENTS SCOPEOF SERVICES.......................................................................................................................................... SITEDESCRIPTION.............................................................................................................................................2 PROPOSEDDEVELOPMENT............................................................................................................................2 FIELDSTUDIES......................................................................................................................................................2 REGIONALGEOLOGY......................................................................................................................................2 SITESOILS..............................................................................................................................................................3 ArtificialFill ...................................................................................................................................................... 3 NativeAlluvial Soils........................................................................................................................................ 3 SURFACE & GROUND WATER......................................................................................................................4 TECTONIC FAULTING AND REGIONAL SEISMICITY............................................................................4 Secondary Seismic Constraints....................................................................................................................4 Summary:..........................................................................................................................................................4 RESULTS OF LABORATORY TESTING.........................................................................................................5 CONCLUSIONS...................................................................................................................................................5 RECOMMENDATIONS - EARTHWORK CONSTRUCTION.................................................................5 General ............................................................................................................................................................. 5 Demolition.......................................................................................................................................................5 Removals/Processing - General...................................................................................................................6 TransitionalPads.............................................................................................................................................6 ExcavationDifficulty.......................................................................................................................................7 FillPlacement...................................................................................................................................................7 ImportMaterial...............................................................................................................................................7 Observationand Testing............................................................................................................................... 7 GroundWater................................................................................................................................................8 EarthworkSettlements..................................................................................................................................8 RECOMMENDATIONS — FOUNDATIONS.................................................................................................8 General .............................................................................................................................................................8 Conventional Foundation Recommendations..........................................................................................8 FoundationSettlement..................................................................................................................................9 OTHER RECOMMENDATIONS.................................................................................................................... SiteImprovements........................................................................................................................................ I I Landscape Maintenance and Planting........................................................................................................ I I SoilCorrosion............................................................................................................................................... 12 TrenchExcavation........................................................................................................................................ 12 Onsite Utility Trench Backfill..................................................................................................................... 12 GeoTek, Inc. Drainage.......................................................................................................................................................... 12 PLANREVIEW..................................................................................................................................................... 13 LIMITATIONS...................................................................................................................................................... 13 Enclosures: Figure #I, Site Vicinity Map Figure #2, Site Exploration Plan Appendix A, References Appendix B, Test Pit Logs Appendix C, Field Test Results Appendix D, Laboratory Test Results GeoTek, Inc. GeoTek,inc. 320 East Corparar-e Drive 5ute 300 ME!ridian,ID 83642-351 1 (208)888-7010 (208) &M7924 www.800wh3l.rom February 11, 2020 Project No. 2097-ID LASHER ENTERPRISES 3327 N. Eagle Road, Ste. 1 10-135 Meridian, ID 83642 Attention: Mr. Brady Lasher Subject: Geotechnical Evaluation for "Spriggle Parcel Subdivision" — an 11.5± Acre Residential Development — Located Southwest of the North McDermott Road and West Lazy Diamond C Lane Intersection, Meridian, Idaho Dear Mr. Lasher, In accordance with your request, GeoTek, Inc. (GTI) has completed a geotechnical evaluation of the subject property for the construction of a single-family residential development with associated improvements. The purpose of our study was to evaluate the soils underlying the site and to provide recommendations for project design and construction based on our findings. This report outlines the geologic and geotechnical conditions of the site based on current data and provides earthwork and construction recommendations with respect to those conditions. SCOPE OF SERVICES The scope of our services has included the following: I. Review of soils and geologic reports and maps for the site (Appendix A). 2. Site reconnaissance. 3. Review of aerial photographs. 4. Excavating and logging of six (6) exploratory test pits (Appendix B). 5. Obtaining samples of representative soils, as the exploratory test pits were advanced. 6. Performing laboratory testing on representative soil samples (Appendix D). 7. Assessment of potential geologic constraints. 8. Engineering analysis regarding foundation design/construction,foundation settlement,and site preparation. 9. Preparation of this report. GEOTECHNICAL I ENVIRONMENTAL I MATERIALS SPRIGGLE PARCEL SUBDIVISION FEBRUARY 11, 2020 LASHER ENTERPRISES PAGE 2 PROJECT NO. 2097-ID SITE DESCRIPTION The project site consists of an irregularly shaped parcel totaling approximately 1 1.5± acres that is generally bound by an irrigation lateral to the north, North McDermott Road to the east, and vacant agricultural land to the south and west (Figures I and 2). Currently, the property consists of vacant agricultural land and a single-family residence with associated improvements. Access to the site is currently possible from through North McDermott Road. From topographic maps,the site's elevation is approximately 2,515± feet to 2,530± feet above mean sea level. Historically, topography generally directs surface water to the north. PROPOSED DEVELOPMENT It is our understanding that site development would consist of performing typical cut and fill earthwork to attain the desired graded configuration(s) for the construction of a residential subdivision of one- to two-story detached single-family residential structures with associated improvements. It is further assumed that final site grade will be within 5 feet of existing site grade. FIELD STUDIES Subsurface conditions at the site were explored by using a rubber-tired backhoe. Six(6)test pits were advanced onsite. A log of each exploration is included with this report in Appendix B. Six (6) percolation tests were performed on the subject site as well as six (6) initial ground water measurements (Appendix C). Field studies were completed during January of 2020 by field personnel who conducted field excavation location mapping, logged the excavations, and obtained samples of representative soils for laboratory testing.The approximate locations of the explorations are indicated on the enclosed Site Exploration Plan (Figure 2). The Unified Soil Classification System (USCS) Classification was used to visually classify the subgrade soils during the field evaluation. REGIONAL GEOLOGY The subject site is situated within the Boise River Valley, which comprises the northwestern portion of the Snake River Plain physiographic province. The western portion of the Snake River Plain is aligned in a northwest-southeast direction and generally divides the Owyhee mountains to the south from the Central Idaho mountains toward the north (Wood and Clemens, 2004). The headwaters of the Boise River are located in the Central Idaho mountains east of Boise, Idaho. The river leaves the central mountains and enters the Snake River Plain near Barber and drains toward the west into the Snake River near Parma. The Owyhee mountains and the Central Idaho Mountains are composed predominantly of volcanic and igneous rocks. The western portion of the Snake River Plain is a northwest trending complex graben formed by extension and regional uplift along the northern boundary of the basin and range province (Wood and Clemens, 2004). The graben generally forms a basin which has been partially filled with younger sedimentary and volcanic rocks (Malde, 1991). The Boise River Valley is bounded on the northeast by the Boise Front,which is a northwest trending topographic high extending generally from Boise to Emmett, Idaho. The Boise Front consists of GeoTek, Inc. SPRIGGLE PARCEL SUBDIVISION FEBRUARY 11, 2020 LASHER ENTERPRISES PAGE 3 PROJECT NO. 2097-ID Cretaceous aged granitic and metamorphic rocks cut by Tertiary aged rhyolite and overlain with Miocene aged lake sediments (Wood and Clemens, 2004). These units have been cut by northwest trending faults which down drop these units toward the southwest. The faults also provide conduits for Quaternary aged basalt intrusions and flows (Malde, 1991). The depositional environment for the valley floor is dominantly lake laid deposits of sand, silt and clay. These materials were deposited during two periods of lake activity, one during the Miocene and the other during the Pleistocene. This valley infilling process has been subsequently truncated by down faulting within the valley ranging in height from a few feet to over 50 feet. Younger alluvium has been, and continues to be,transported dominantly by water and deposited on the basins gently sloping valley floor and within low-level flood plains. Portions of the alluvial deposits are being down cut by intermittent streams to the flood plain, and as a result stream terraces are being formed. SITE SOILS Artificial Fill Based on our field studies, some spread fills were observed along the perimeter of the site and around the existing structures. This fill is generally associated with the construction of the roadways, onsite structures, and the canal. This spread fill shall be considered artificial fill. Where observed in our test pits, the upper 12 inches of material has been disturbed and contains a moderate amount of organics and roots,this shall be considered artificial fill. Since much of the site has been disturbed, it should be anticipated that deeper fills may be encountered onsite. The "Artificial Fills" are loose and contain organics/roots and are not considered suitable for support of foundations. All artificial fill material should be removed as described in the "Removals" section of this report. Native Alluvial Soils Alluvial soils encountered generally consisted surficial layers of silts with sands, underlain by silty sands, poorly graded sands and poorly graded gravels with sand. The moisture content within the alluvial materials was generally moist near ground surface and moist to saturated at depth.The consistency of these soils ranged from soft to firm near surface and dense to moderately hard at depth. We anticipate that the onsite soils can be excavated with conventional earthwork equipment. Partially cemented layers of material were encountered in some of our excavations; however, we anticipate that the onsite soils can be excavated with conventional earthwork equipment equivalent to CAT D9R dozers and CAT 235 excavators. Special excavation equipment and techniques may be necessary dependent upon if harder materials are encountered during construction. After artificial fill is removed, the upper 12 inches of the alluvium will require, at a minimum, some removal and/or processing efforts to be considered suitable for the support of the proposed site improvements. Locally deeper processing/removals may be necessary. Refer to the "Recommendations Earthwork Construction" section of this report for specific site preparation recommendations. GeoTelc, Inc. SPRIGGLE PARCEL SUBDIVISION FEBRUARY 11, 2020 LASHER ENTERPRISES PAGE 4 PROJECT NO. 2097-ID SURFACE & GROUND WATER Ground water was encountered during our field investigation at a depth of 7.3' (TP-4) to 8.8' (TP-6) below existing ground surface. Irrigation laterals exist adjacent to the site and they transmit water on a periodic basis. Generally, irrigation ditches and canals will locally influence ground water during the irrigation season (i.e., April through October). If encountered,wet materials should be spread out and air-dried or mixed with drier soils to reduce their moisture content as appropriate for fill placement. Ground water is not anticipated to adversely affect planned development, provided that earthwork construction methods comply with recommendations contained in this report or those made subsequent to review of the improvement plan(s). GTI assumes that the design civil engineer of record will evaluate the site for potential flooding and set grades such that the improvements are adequately protected. These observations reflect conditions at the time of this investigation and do not preclude changes in local ground water conditions in the future from natural causes, damaged structures (lines, pipes etc.), or heavy irrigation. The groundwater monitoring results obtained are depicted in a table format in Appendix C. TECTONIC FAULTING AND REGIONAL SEISMICITY The site is situated in an area of active as well as potentially active tectonic faults, however no faults were observed during our field evaluation.There are a number of faults in the regional area,which are considered active and would have an affect on the site in the form of ground shaking, should they be the source of an earthquake. It is reasonable to assume that structures built in this area will be subject to at least one seismic event during their life, therefore, it is recommended that all structures be designed and constructed in accordance with the International Building Code (IBC). Based on our experience in the general vicinity, references in our library, field evaluation of the site, a Seismic Design Site Class Designation of `D' may be used for seismic design. Secondary Seismic Constraints The following list includes other potential seismic related hazards that have been evaluated with respect to the site, but in our opinion, the potential for these seismically related constraints to affect the site is considered negligible. * Liquefaction * Dynamic Settlements * Surface Fault Rupture * Ground Lurching or Shallow Ground Rupture Summary: It is important to keep in perspective that if a seismic event were to occur on any major fault, intense ground shaking could be induced to this general area. Potential damage to any settlement sensitive structures would likely be greatest from the vibrations and impelling force caused by the inertia of the structures mass than that created from secondary seismic constraints. Considering the subsurface soil conditions and local seismicity, it is estimated that the site has a low risk associated with the potential for these phenomena to occur and adversely affect surface improvements.These potential risks are no greater at this site than they are for other structures and improvements developed on the alluvial materials in this vicinity. GeoTelc, Inc. SPRIGGLE PARCEL SUBDIVISION FEBRUARY 11, 2020 LASHER ENTERPRISES PAGE 5 PROJECT NO. 2097-ID RESULTS OF LABORATORY TESTING Laboratory tests were performed on representative samples of the onsite earth materials in order to evaluate their physical and chemical characteristics.The tests performed, and the results obtained are presented in Appendix D. CONCLUSIONS Based on our field exploration, laboratory testing and engineering analyses, it is our opinion that the subject site is suited for development from a geotechnical engineering viewpoint. The recommendations presented herein should be incorporated into the final design, grading, and construction phases of development. The engineering analyses performed concerning site preparation and the recommendations presented below have been completed using the information provided to us regarding site development. In the event that the information concerning proposed development is not correct, the conclusion and recommendations contained in this report shall not be considered valid unless the changes are reviewed, and conclusions of this report are modified or approved in writing by this office. RECOMMENDATIONS - EARTHWORK CONSTRUCTION General All grading should conform to the International Building Code (IBC) and the requirements of the City of Meridian except where specifically superseded in the text of this report. During earthwork construction all removals, drain systems, slopes,and the general grading procedures of the contractor should be observed and the fill selectively tested. If unusual or unexpected conditions are exposed in the field, they should be reviewed by this office and, if warranted, modified and/or additional recommendations will be offered. It is recommended that the earthwork contractor(s) perform their own independent reconnaissance of the site to observe field conditions firsthand. If the contractor(s) should have any questions regarding site conditions,site preparation, or the remedial recommendations provided,they should contact an engineer at GeoTek for any necessary clarifications prior to submitting earthwork bids.All applicable requirements of local and national construction and general industry safety orders,the Occupational Safety and Health Act, and the Construction Safety Act should be met. Demolition The following recommendations are provided as guidelines in the event that structures are encountered that are not intended to remain. I. All existing surface or subsurface structures (not intended to remain), within the area to be developed, should be razed and moved off site. 2. If a septic tank (to be abandoned or below a proposed improvement) is located within the project site, it is recommended that it be pumped out and, with few exceptions, likely removed. Any leach lines, seepage pits, or other pipes associated with this structure should also be removed or properly abandoned. GeoTelc, Inc. SPRIGGLE PARCEL SUBDIVISION FEBRUARY 11, 2020 LASHER ENTERPRISES PAGE 6 PROJECT NO. 2097-ID 3. If any wells are encountered, an attempt should be made to identify the owner and purpose of the well. Well abandonment should adhere to the recommendations provided by the Idaho Department of Water Resources, the Public Health Department, or any other government agencies. If the well is located in the area of a proposed structure, these recommendations should be reviewed by GTI and, if warranted,additional geotechnical recommendations will be offered. Removals/Processing - General Presented below are removal/processing recommendations for the various soils encountered on the project. Debris, vegetation, and other deleterious material should be stripped/removed from areas proposed for structural improvements. Based on a review of the exploratory logs and our site reconnaissance, after the artificial fill and deleterious material are removed (up to 12 inches where observed), a minimum removal/processing depth of 12 inches into alluvial materials should be accomplished across the site. If the left in place soils can be scarified to encounter a competent layer below; they may be processed in place; otherwise,they should be removed to competent material. Locally deeper removals/processing may be necessary based on the field conditions exposed. Since much of has been disturbed, it should be anticipated that deeper fills may be encountered onsite. We recommend that all deleterious soils be removed from beneath the foundations and building pads and replaced with a low expansive structural fill. The exposed ground surface should be moisture conditioned and compacted a minimum depth of 12 inches to provide uniform foundation support. Also, a minimum of 12 inches of compacted structural fill below the bottom of footings should be provided.A minimum relative compaction of 90 percent of the laboratory maximum modified density (ASTM D 1557) at a moisture content of optimum or above is necessary to generate any near surface settlements. Locally deeper removals/processing may be necessary based on the conditions exposed. Removal bottoms should be checked by a representative of GeoTek, Inc. to see if deeper removals are necessary. If existing improvements or property line restrictions limit removals, condition specific recommendations would be provided on a case-by-case basis. During earthwork construction, care should be taken by the contractor so that adverse ground movements or settlements are not generated affecting existing improvements. Transitional Pads Transitional pads are defined in this report as pads which are partially cut and partially fill.To mitigate some of the differential settlement which will occur on transitional pads,the cut side should be over- excavated/processed to a minimum depth equal to 2 feet below the bottom of the footings or to the depth of the fill,whichever is less. On transitional pads with more than 7.5 feet of fill, plans need to be reviewed by GTI and site-specific recommendations will be provided. GeoTek, Inc. SPRIGGLE PARCEL SUBDIVISION FEBRUARY 11, 2020 LASHER ENTERPRISES PAGE 7 PROJECT NO. 2097-ID Excavation Difficulty We anticipate that the onsite soils can be excavated with conventional earthwork. Seasonal conditions could cause wet soil conditions to occur onsite. Depending on the depth of cuts, it should be expected that special excavation and fill placement measures may be necessary. Wet materials should be spread out and air-dried or mixed with drier soils to reduce their moisture content to the appropriate level for fill placement. Frozen soils, if encountered, should be removed and allowed to thaw prior to any fill placement or construction. Removal bottoms should be checked by a representative of GTI to see if deeper removals are necessary. Fill Placement Subsequent to completing removals/processing and ground preparation, the excavated onsite and/or imported soils may be placed in relatively thin lifts (less than 8 inches thick), cleaned of vegetation and debris, brought to at least optimum moisture content, and compacted to a minimum relative compaction of 90 percent of the laboratory standard (ASTM D 1557). Import Material Potentially, soils will be imported to the site for earthwork construction purposes. A sample of any intended import material should first be submitted to GTI so that, if necessary, additional laboratory or chemical testing can be performed to verify that the intended import material is compatible with onsite soils. In general, import material should be within the following minimum guidelines: * Free of organic matter and debris. * Maintain less than 0.2 percent sulfate content. * Maintain less than 3.0 percent soluble material. * Maintain less than 0.02 percent soluble chlorides. * Maintain less than 0.2 percent sodium sulfate content. * Maintain a Plasticity Index less than 12 (i.e., low expansive). * One hundred percent passing the six-inch screen. * At least seventy-five percent passing a three-inch screen. * Maintain between 5 and 20 percent passing the No. 200 screen * Maintain at least 20 percent on No. 4 screen Observation and Testing During earthwork construction all removal/processing and the general grading procedures should be observed, and the fill selectively tested by a representative(s) of GTI. If unusual or unexpected conditions are exposed in the field,they should be reviewed by GTI and if warranted, modified and/or additional recommendations will be offered. GeoTelc, Inc. SPRIGGLE PARCEL SUBDIVISION FEBRUARY 11, 2020 LASHER ENTERPRISES PAGE 8 PROJECT NO. 2097-ID Ground Water Ground water was encountered during our field investigation at a depth of 7.3' (TP-4) to 8.8' (TP-6) below existing ground surface. Based on site conditions in the future, a transient high ground water condition could develop over a clay or less permeable layer and this condition could generate down gradient seepage. The possible effect these layers could have on this and adjacent sites should be considered and can best be evaluated in the field during grading. If warranted by exposed field conditions, it may be recommended that a drainage system be established to collect and convey any subsurface water to an appropriate location for drainage. Typically, potential areas of seepage are difficult to identify prior to their occurrence; therefore, it is often best to adopt a "wait and see" approach to determine if any seepage conditions do develop, at which time specific recommendation to mitigate an identified condition can be provided. Earthwork Settlements Ground settlement should be anticipated due to primary consolidation and secondary compression. The total amount of settlement and time over which it occurs is dependent upon various factors, including material type, depth of fill, depth of removals, initial and final moisture content, and in-place density of subsurface materials. Compacted fills,to the heights anticipated, are not generally prone to excessive settlement. However, some settlement of the left-in-place alluvium is expected, and the majority of this settlement is anticipated to occur during grading. RECOMMENDATIONS — FOUNDATIONS General Foundation design and construction recommendations are based on preliminary laboratory testing and engineering analysis performed on near surface soils. The proposed foundation systems should be designed and constructed in accordance with the guidelines contained herein and in the International Building Code. Based on our experience in the area, the soils onsite should have a negligible corrosive potential to concrete and metal, materials selected for construction purposes should be resistant to corrosion. Where permitted by building code, PVC pipe should be utilized. All concrete should be designed, mixed, placed, finished, and cured in accordance with the guidelines presented by the Portland Cement Association (PCA) and the American Concrete Institute (ACI). Based on our grading recommendations,the soils beneath the foundations are anticipated to have low expansion potential. Therefore, foundation recommendations for low expansive soil conditions are provided below. If more expansive soils are encountered, the pad(s) will either need to be regraded and the more expansive soils removed by the contractor—or increased foundation recommendations will need to be provided. Conventional Foundation Recommendations Column loads are anticipated to be 50 kips or less while wall loads are expected to be 3 kips per linear foot or less. The conventional recommendations provided are from a geotechnical engineering perspective (i.e.,for expansive conditions) and are not meant to supersede the design by the project's structural engineer. GeoTek, Inc. SPRIGGLE PARCEL SUBDIVISION FEBRUARY 11, 2020 LASHER ENTERPRISES PAGE 9 PROJECT NO. 2097-ID Preliminary recommendations for foundation design and construction are presented below. The specific criteria to be used should be verified on evaluation of the proposed buildings,structural loads, and expansion and chemical testing performed after grading is complete. The bearing values indicated are for the total dead, plus frequently applied, live loads and may be increased by one third for short duration loading which includes the effects of wind or seismic forces. When combining passive pressure and friction for lateral resistance,the passive component should be reduced by one-third. A grade beam, reinforced as below and at least 12 inches wide, should be utilized across all large entrances. The base of the grade beam should be at the same elevation as the bottom of the adjacent footings. Footings should be founded at a minimum depth of 24 inches below lowest adjacent ground surface as required by local codes to extend below the frost line. Reinforcement for spread footings should be designed by the project's structural engineer. For foundations systems including a crawl space, it is recommended that it be designed so that water is not allowed to penetrate the crawl space. Proper grading and backfill for the foundations are critical and should adhere to the"fill placement"and "drainage" recommendations of this evaluation as well as local building codes. Soil Minimum Allowable Passive Maximum Footing Expansion Footing Bearing Coefficient Earth Earth Type Depth Pressure of Friction Pressure Pressure Classification (inches) (psf) (psf/ft) (psf) Strip/Spread Low 24 2,000 0.35 250 3,000 The coefficient of friction and passive earth pressure values recommended are working values. Strip footings should have a minimum width of one foot and spread footings should have a minimum soil to concrete area of four-square feet. Increases are allowed for the bearing capacity of the footings at a rate of 250 pounds per square foot for each additional foot of width and 250 pounds per square foot for each additional foot of depth into the recommended bearing material, up to a maximum outlined. If the bearing value exceeds 3,000 psf, an additional review by GTI is recommended. As mentioned earlier,the exposed ground surface should be moisture conditioned and compacted a minimum depth of 12 inches below bottom of footings. Foundation Settlement Provided that the recommendations contained in this report are incorporated into final design and construction phase of development, total settlement is estimated to be less than one inch and differential settlement is estimated to be less than 0.75 inches for a 25-foot span. Two-way angular distortions due to settlements are not estimated to exceed 1/400. The structures should be loaded uniformly so as to avoid any localized settlements. GeoTelc, Inc. SPRIGGLE PARCEL SUBDIVISION FEBRUARY 11, 2020 LASHER ENTERPRISES PAGE 10 PROJECT NO. 2097-ID PAVEMENT SECTIONS Pavement sections presented in the following table are based on an R-value result of 10, Ada County Highway District Development(ACHD) pre-assigned traffic index(s)for residential construction and estimated traffic index(s) for commercial construction, and the guidelines presented in the latest edition of the ACHD Development Policy Manual. These pavement sections are presented for planning purposes only and should be verified based on specific laboratory testing performed subsequent to rough grading of the site. Pavement Construction and Maintenance All section changes should be properly transitioned. If adverse conditions are encountered during the preparation of subgrade materials, special construction methods may need to be employed. All subgrade materials should be processed to a minimum depth of 12 inches and compacted to a minimum relative compaction of 90 percent near optimum moisture content. All aggregate base should be compacted to a minimum relative compaction of 95 percent at optimum moisture content. r. - - MINIMUM MINIMUM AGGREGATE ASSUMED TRAFFIC SUBGRADE ASPHALT THICKNESS (in.) RIGHT-OF-AWAY R-VALUE CONCRETE Aggregate Subbase THICKNESS Base (3/4" (in.) minus)* (Pitrun)* Residential Normal Traffic 10 2.5 4.0 12.0 TI = 6.0 Collector Normal Traffic 10 3.0 6.0 16.0 TI = 8.0 = J *Aggregate Base and Subbase gradation specification requirement per the current edition of the Idaho Standards for Public Works Construction (ISPWC) Manual. 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. The recommended pavement sections provided are meant as minimums. If thinner or highly variable pavement sections are constructed, increased maintenance and repair should be expected. If the ADT (average daily traffic) or ADTT (average daily truck traffic) increases beyond that intended,as reflected by the traffic index(s) used for design, increased maintenance and repair could be required for the pavement section. Positive site drainage should be maintained at all times.Water should not be allowed to pond or seep into the ground. If planters or landscaping are adjacent to paved areas, measures should be taken to minimize the potential for water to enter the pavement section. GeoTek, Inc. SPRIGGLE PARCEL SUBDIVISION FEBRUARY 11, 2020 LASHER ENTERPRISES PAGE I I PROJECT NO. 2097-ID OTHER RECOMMENDATIONS Site Improvements As is commonly known, expansive soils are problematic with respect to the design, construction and long-term performance of concrete flatwork. Due to the nature of concrete flatwork, it is essentially impossible to totally mitigate the effects of soil expansion. Typical measures to control soil expansion for structures include; low expansive soil caps, deepened foundation system, increased structural design,and soil presaturation. As they are generally not cost effective,these measures are very seldom utilized for flatwork because it's less costly to simply replace any damaged or distressed sections than to "structurally" design them. Even if "structural" design parameters are applied to flatwork construction,there would still be relative movements between adjoining types of structures and other improvements (e.g., curb and sidewalk). This is particularly true as the level of care during construction of flatwork is often not as meticulous as that for structures. Unfortunately, it is fairly common practice for flatwork to be poured on subgrade soils, which have been allowed to dry out since site grading. Generally, after flatwork construction is completed, landscape irrigation begins, utility lines are pressurized, and drainage systems are utilized; presenting the potential for water to enter the dry subgrade soils, causing the soil to expand. Recommendations for exterior concrete flatwork design and construction can be provided upon request. If, in the future, any additional improvements are planned for the site, recommendations concerning the geological or geotechnical aspects of design and construction of said improvements could be provided upon request.This office should be notified in advance of any fill placement,grading, or trench backfilling after rough grading has been completed. This includes any grading, utility trench and retaining wall backfills. Landscape Maintenance and Planting Water has been shown to weaken the inherent strength of all earth materials. Slope stability is significantly reduced by overly wet conditions. Graded slopes constructed within and utilizing onsite materials would be erosive. Eroded debris may be minimized, and surficial slope stability enhanced by establishing and maintaining a suitable vegetation cover as soon as possible after construction. Compaction to the face of fill slopes would tend to minimize short-term erosion until vegetation is established. Plants selected for landscaping should be lightweight, deep-rooted types, which require little water and are capable of surviving the prevailing climate. From a geotechnical standpoint leaching is not recommended for establishing landscaping. If the surface soils are processed for the purpose of adding amendments, they should be recompacted to 90 percent compaction. Only the amount of irrigation necessary to sustain plant life should be provided. Over watering the landscape areas could adversely affect proposed site improvements. We recommend that any proposed open bottom planter areas adjacent to proposed structures, be eliminated for a minimum distance of 5 feet and desert landscape using xeriscape technology be used outside of this buffer zone. As an alternative, closed bottom type planter could be utilized.An outlet, placed in the bottom of the planter, could be installed to direct drainage away from structures or any exterior concrete flatwork. Irrigation timers should be adjusted on a monthly basis. GeoTek, Inc. SPRIGGLE PARCEL SUBDIVISION FEBRUARY 11, 2020 LASHER ENTERPRISES PAGE 12 PROJECT NO. 2097-ID Soil Corrosion Based on our experience in the area, the soils onsite should have a negligible corrosive potential to concrete and metal, materials selected for construction purposes should be resistant to corrosion. Where permitted by building code, PVC pipe should be utilized. All concrete should be designed, mixed, placed, finished, and cured in accordance with the guidelines presented by the Portland Cement Association (PCA) and the American Concrete Institute (ACI). Trench Excavation All footing trench excavations should be observed by a representative of this office prior to placing reinforcement. Footing trench spoil and any excess soils generated from utility trench excavations should be compacted to a minimum relative compaction of 90 percent if not removed from the site. Considering the nature of the onsite soils, it should be anticipated that caving or sloughing could be a factor in excavations. Shoring or excavating the trench walls and slopes to the angle of repose (typically 25 to 45 degrees) may be necessary and should be anticipated in non-cemented soils. All excavations should be observed by one of our representatives and conform to national and local safety codes. Onsite Utility Trench Backfill Considering the overall nature of the soil encountered onsite, it should be anticipated that materials will need to be imported to the site for use as pipe bedding and pipe zone material. All utility trench backfill should be brought to near optimum moisture content and then compacted to obtain a minimum relative compaction of 90 percent of the laboratory standard. Compaction testing and observation, along with probing should be performed to verify the desired results.Sand backfill, unless excavated from the trench, should not be used adjacent to perimeter footings or in trenches on slopes. Compaction testing and observation, along with probing should be performed to verify the desired results. Sand backfill, unless excavated from the trench, should not be used adjacent to perimeter footings or in trenches on slopes. Compaction testing and observation, along with probing should be performed to verify the desired results. Offsite utility trenches should be compacted to a minimum of 90 relative compaction. Compaction testing and observation, along with probing should be performed to verify the desired results. Drainage Positive site drainage should be maintained at all times in accordance with the IBC. Drainage should not flow uncontrolled down any descending slope. Water should be directed away from foundations and not allowed to pond and/or seep into the ground. Pad drainage should be directed toward the street or other approved area. The ground immediately adjacent to the foundation shall be sloped away from the building at a minimum of 5-percent for a minimum distance of 10 feet measured perpendicularly to the face of the wall. If physical obstructions prohibit 10 feet of horizontal distance,a 5-percent slope shall be provided to an approved alternate method of diverting water away from the foundation. Swales used for this purpose shall be sloped a minimum of 2-percent where located within 10 feet of the building foundation. Impervious surfaces within 10 feet of the building foundation shall be sloped a minimum of 2-percent away from the building. Roof gutters and down spouts should be utilized to control roof drainage. Down spouts should outlet onto paved areas or a minimum of five feet from proposed structures or into a subsurface drainage system. Areas of seepage may develop due to irrigation or heavy rainfall. Minimizing irrigation will lessen this potential. If areas of seepage develop, recommendations for minimizing this effect could be provided upon request. GeoTek, Inc. SPRIGGLE PARCEL SUBDIVISION FEBRUARY 11, 2020 LASHER ENTERPRISES PAGE 13 PROJECT NO. 2097-ID PLAN REVIEW Final grading, foundation, and improvement plans should be submitted to this office for review and comment as they become available, to minimize any misunderstandings between the plans and recommendations presented herein. In addition,foundation excavations and earthwork construction performed on the site should be observed and tested by this office. If conditions are found to differ substantially from those stated, appropriate recommendations would be offered at that time. LIMITATIONS The materials encountered on the project site and utilized in our laboratory study are believed representative of the area; however, soil materials vary in character between excavations and conditions exposed during mass grading. Site conditions may vary due to seasonal changes or other factors. GeoTek, Inc. assumes no responsibility or liability for work, testing, or recommendations performed or provided by others.Since our study is based upon the site materials observed, selective laboratory testing and engineering analysis, the conclusions and recommendations are professional opinions. These opinions have been derived in accordance with current standards of practice and no warranty is expressed or implied. Standards of practice are subject to change with time. The opportunity to be of service is greatly appreciated. If you have any questions concerning this report or if we may be of further assistance, please do not hesitate to contact the undersigned. L Lc Respectfully submitted, �.sgxONA�STE GeoTek, Inc. O� ��G 9F0 a 10884 OF oq o C. *r i - zo Tyler S. Lydeen, El David C. Waite, PE Staff Professional Senior Engineer GeoTek, Inc. 11S r2C HM 20 W-Chidden [A x a 1° � n � R W w r ammbn M w htr►iuian W W L]SI ick Rd W UsleckAd x x n p a f h [t,erry I r W C,eW Ln A Chary+LP APPROXIMATE SITE LOCATION Source:Google Maps 2019, GeoTek Field Observations, 2020. Not to Scale FIGURE I SITEVICINITY MAP r6--� Spriggle Parcel Subdivision SWC of the N McDermott Rd&W Lazy Diamond C Ln Intersection GEOTEK Meridian, Idaho GEOTECHNICAL I ENVIRONMENTAL I MATERIALS Prepared for: Lasher Enterprises Project No.: Report Date: Drawn By: 320 E.Corporate Dr,Suite 300, Meridian,ID 83642 2097-ID February 2020 TSL (208)888-7010 (phone)/(208)888-7924(FAX) ��d .* r,, 1 1 t 7! r '7 SITE 1 4 - .r. J -� - 0 Z x APPROXIMATE TEST PIT LOCATIONS Source:Google Earth 2019, GeoTel< Field Observations, 2020. Not to Scale FIGURE 2 SITE EXPLORATION PLAN Spriggle Parcel Subdivision SWC of the N McDermott Rd &W Lazy Diamond C Ln Intersection GEOTEK Meridian, Idaho GEOTECHNICAL I ENVIRONMENTAL I MATERIALS Prepared for: Lasher Enterprises Project No.: Report Date: Drawn By: 320 E.Corporate Dr,Suite 300, Meridian,ID 83642 2097-ID February 2020 TSL (208)888-7010 (phone)1(208)888-7924(FAX) APPENDIX A GeoTek, Inc. REFERENCES Ada County Highway District Development Policy Manual, Revised by Resolution No. 690, October 2003 ASTM, 200, "Soil and Rock: American Society for Testing and Materials," vol. 4.08 for ASTM test methods D-420 to D-4914, 153 standards, 1,026 pages; and vol. 4.09 for ASTM test method D- 4943 to highest number. Breckinridge, R.M., Lewis, R.S.,Adema, G.W.,Weisz, D.W., 2003, Map of Miocene and Younger Faults in Idaho, Idaho Geological Survey, University of Idaho Collett, Russell A., 1980, Soil Survey of Ada County, Eastern Part, United States Department of Agriculture Soil Conversation Service, United States Department of the Interior Bureau of Land Management, Idaho Soil Conservation Commission, University of Idaho College of Agriculture. Day, Robert W., 1999, Geotechnical and Foundation Engineering— Design and Construction Day, Robert W., 2002, Geotechnical Earthquake Engineering Handbook GeoTek, Inc., In-house proprietary information. Idaho Department of Water Resources, Treasure Valley Hydrology — Geology,January 2003 Idaho Department of Water Resources, Well Information, Well Driller Reports, 2002 Idaho Transportation Department CD-ROM Publications, September 2003 Johnson, Bruce R. and Raines, Gary L., 1995, Digital representation of the Idaho state geologic map: a contribution to the Interior Columbia Basin Ecosystem Management Project. USGS Open-File Report 95-690 Malde, H.E., 1991. Quaternary geology and structural history of the Snake River Plain, Idaho and Oregon. In: The Geology of North America, Quaternary Nonglacial Geology: Conterminous U.S., Vol. K-2, 252-281 pp. Othberg, K.L., 1994. Geology and geomorphology of the Boise Valley and adjoining areas, western Snake River Plain, Idaho. Idaho Geological Survey Bulletin 29: 54 pp. USGS, Cloverdale Quadrangle, 7.5-Minute Series Topographic Map, 1979. USGS, 2003, Seismic Hazard Map of Idaho, Peak Acceleration (%g)with 2% Probability of Exceedance in 50 years. GeoTek, Inc. APPENDIX 6 GeoTek, Inc. LOG GENERAL NOTES CONSISTENCY OF FINE-GRAINED SOILS RELATIVE DENSITY OF COARSE-GRAINED SOILS Unconfined Standard Standard Penetration(SPT)or N. Compressive Penetration or N- Consistency Relative Density Strength,Qu,psf Value(SS) Blows/Ft Value(SS)Blows/Ft < 500 <2 Very Soft 0-3 Very Loose 500- 1,000 2-3 Soft 4-9 Loose 1,001 -2,000 4-7 Firm 10-29 Medium Dense 2,001 -4,000 8- 16 Stiff 30-49 Dense 4,001 -8,000 17-32 Very Stiff 50+ Very Dense >8,001 32+ Hard SPT penetration test using 140 pound hammer,with 30 inch free fall on 2 inch outside diameter(1-3/8 ID)sampler For ring sampler using 140 lb hammer,with a 30 inch free fall on 3 inch outside diameter(2-1/2 ID)sample, use N-value x 0.7 to get Standard N-value For fine grained soil consistency,thumb penetration used per ASTM D-2488 RELATIVE PROPORTIONS OF SAND&GRAVEL GRAIN SIZE TERMINOLOGY Descriptive Term of other constituents Percent of Dry Major Component Particle Size Weight of Sample Trace < 15 Boulders Over 12 inches With 15-29 Cobbles 3 inches to 12 inches Modifier > 30 Gravel #4 Sieve to 3 inches Sand #200 Sieve to#4 Sieve Silt or Clay Passing#200 Sieve RELATIVE HARDNESS OF CEMENTED SOILS(CALICHE) Description General Characteristics Very Dense to Moderately Hard Partially Cemented Granular Soil -Can be carved with a knife and broken with force by hand. Very Stiff to Moderately Hard Partially Cemented Fine-Grained Soil -Can be carved with a knife and broken with force by hand. Moderately Hard Moderate hammer blow required to break a sample Hard Heavy hammer blow required to break a sample Very Hard Repeated heavy hammer blow required to break a sample LOG LEGEND MATERIAL DESCRIPTION Soil Pattern USCS Symbol I USCS Classification FILL Artificial Fill GP or GW Poorly/Well graded GRAVEL GM Silty GRAVEL GC Clayey GRAVEL GP-GM or GW-GM Poorly/Well graded GRAVEL with Silt GP-GC or GW-GC Poorly/Well graded GRAVEL with Clay SP or SW Poorly/Well graded SAND SM Silty SAND Sc Clayey SAND SP-SM or SW-SM Poorly/Well graded SAND with Silt SP-SC or SW-SC Poorly/Well graded SAND with Clay SC-SM Silty Clayey SAND ML SILT MH Elastic SILT CL-ML Silty CLAY CL Lean CLAY CH Fat CLAY PCEM PARTIALLY CEMENTED CEM CEMENTED BDR BEDROCK SAMPLING SPT Ring Sample LNR No Recovery Bulk Sample Water Table CONSISTENCY Cohesionless Soils Cohesive Soils Cementation VL Very Loose So Soft MH Moderately Hard L Loose F Firm H Hard MD Medium Dense S Stiff VH Very Hard D Dense VS Very Stiff VD Very Dense TEST PIT LOG LOGGED BY: TSL AE:�� PROJECT#: 2097-ID METHOD: Backhoe PROJECT: Spriggle Parcel Subdivision EXCAVATOR: JustDiglt CLIENT: Lasher Enterprises DATE: 1/3I/20 GE 0 T E K LOCATION: Southwest of the N McDermott Rd and W Lazy Diamond C Ln ELEVATION: SAMPLES s TEST PIT NUMBER: TP-I 41 REMARKS aai a a N = G c H V H rn m 7 MATERIAL DESCRIPTION AND COMMENTS FILL Dk. Brown to Lt. Brown,Artificial Fill SILT with Sand, Moist So Roots/Organics to 1.0' I — ML Dk. Brown to Lt. Brown,SILT with Sand, Moist F 2 — 3 SM Brown to Lt. Brown,Silty SAND,Slightly Moist D 4 — 5 GP Reddish Brown to Brown, Poorly graded GRAVEL with Sand, D Percolation Test Conducted 6 — Slightly Moist at 5.0' 7 — 8 Saturated Groundwater Depth at 8.1' 9 — per 2/3/20 Measurement 10 — II — 12 — END OF TEST PIT @ 1 1.5- 13 — 14 — 15 — 16 — 17— 18 — 19 — 20 320 E. Corporate Drive,Suite 300, Meridian, Idaho 83642 1 Office: (208)888-7010 Fax: (208)888-7924 TEST PIT LOG LOGGED BY: TSL AE:�� PROJECT#: 2097-ID METHOD: Backhoe PROJECT: Spriggle Parcel Subdivision EXCAVATOR: JustDiglt CLIENT: Lasher Enterprises DATE: 1/3I/20 GE 0 T E K LOCATION: Southwest of the N McDermott Rd and W Lazy Diamond C Ln ELEVATION: SAMPLES s TEST PIT NUMBER: TP-2 41 REMARKS aai a a N = G c H V H rn m 7 MATERIAL DESCRIPTION AND COMMENTS FILL Dk. Brown to Lt. Brown,SILT with Sand, Moist So Roots/Organics to 1.0' I — ML Dk. Brown to Lt. Brown,SILT with Sand, Moist F 2 — 3 SM Brown to Lt. Brown,Silty SAND,Slightly Moist D 4 XPercolation Test Conducted at 3.5' 5 6 SP Brown,Poorly graded SAND, Moist D 7 — 8 Saturated Groundwater Depth at 7.9' 9 — per 2/3/20 Measurement 10 — GP Brown,Poorly graded GRAVEL with Sand,Saturated D 11 — END OF TEST PIT @ 1 1.0' 12 — 13 — 14 — 15 — 16 — 17— 18 — 19 — 20 320 E. Corporate Drive,Suite 300, Meridian, Idaho 83642 Office: (208)888-7010 Fax: (208)888-7924 TEST PIT LOG LOGGED BY: TSL AE:�� PROJECT#: 2097-ID METHOD: Backhoe PROJECT: Spriggle Parcel Subdivision EXCAVATOR: JustDiglt CLIENT: Lasher Enterprises DATE: 1/3I/20 GE 0 T E K LOCATION: Southwest of the N McDermott Rd and W Lazy Diamond C Ln ELEVATION: SAMPLES s TEST PIT NUMBER: TP-3 41 REMARKS aai a a N = G c H H V rn m 7 MATERIAL DESCRIPTION AND COMMENTS FILL Brown,SILT with Sand, Moist So Roots/Organics to 1.0' I — ML Brown,SILT with Sand, Moist 2 — PCEM Brown,PARTIALLY CEMENTED Silty Sand,Slightly Moist MH 3 4 — GP Reddish Brown to Brown, Poorly graded GRAVEL with Sand, D Percolation Test Conducted 5 — Slightly Moist at 4.0' 6 — 7 — Groundwater Depth at 7.3' 8 — Saturated per 2/3/20 Measurement 9 — 10 — 1 1 — END OF TEST PIT @ 1 1.0' 12 — 13 — 14 — 15 — 16 — 17— 18 — 19 — 20 320 E. Corporate Drive,Suite 300, Meridian, Idaho 83642 Office: (208)888-7010 Fax: (208)888-7924 TEST PIT LOG LOGGED BY: TSL AE:�� PROJECT#: 2097-ID METHOD: Backhoe PROJECT: Spriggle Parcel Subdivision EXCAVATOR: JustDiglt CLIENT: Lasher Enterprises DATE: 1/3I/20 GE 0 T E K LOCATION: Southwest of the N McDermott Rd and W Lazy Diamond C Ln ELEVATION: SAMPLES s TEST PIT NUMBER: TP-4 REMARKS aai a a N = G c H V H rn m 7 MATERIAL DESCRIPTION AND COMMENTS FILL Dk. Brown to Brown,SILT with Sand, Moist So Roots/Organics to 1.0' I -X ML Dk. Brown to Brown,SILT with Sand, Moist F 2 SM Brown to Lt. Brown,Silty SAND,Moist D Percolation Test Conducted 3 — at 2.0' 4 — SP Brown to Lt. Brown, Poorly graded SAND, Moist D 5 6 — 7 — GP Brown to Lt. Brown, Poorly graded GRAVEL with Sand,Saturated 8 — Groundwater Dpeth at 7.5' per 2/3/20 Measurement 9 — 10 — END OF TEST PIT @ 10.0- II — 12 — 13 — 14 — 15 — 16 — 17— 18 — 19 — 20 320 E. Corporate Drive,Suite 300, Meridian, Idaho 83642 Office: (208)888-7010 Fax: (208)888-7924 TEST PIT LOG LOGGED BY: TSL AE:�� PROJECT#: 2097-ID METHOD: Backhoe PROJECT: Spriggle Parcel Subdivision EXCAVATOR: JustDiglt CLIENT: Lasher Enterprises DATE: 1/3I/20 GE 0 T E K LOCATION: Southwest of the N McDermott Rd and W Lazy Diamond C Ln ELEVATION: SAMPLES s TEST PIT NUMBER: TP-5 41 REMARKS aai a a N = G c H H V rn m 7 MATERIAL DESCRIPTION AND COMMENTS FILL Dk. Brown to Brown,SILT with Sand, Moist So Roots/Organics to 1.0' I — ML Dk. Brown to Brown,SILT with Sand, Moist F 2 — 3 — PCEM Brown,PARTIALLY CEMENTED Silty Sand,Slightly Moist MH 4 — SP Brown,Poorly graded SAND, Moist D 5 — Percolation Test Conducted at 5.0' 6 GP Brown,Poorly graded GRAVEL with Sand, Moist to Saturated D 7 — 8 — Groundwater Depth at 7.8' Saturated per 2/3/20 Measurement 9 — 10 — 1 1 — END OF TEST PIT @ 10.5' 12 — 13 — 14 — 15 — 16 — 17— 18 — 19 — 20 320 E. Corporate Drive,Suite 300, Meridian, Idaho 83642 1 Office: (208)888-7010 Fax: (208)888-7924 TEST PIT LOG LOGGED BY: TSL AE:�� PROJECT#: 2097-ID METHOD: Backhoe PROJECT: Spriggle Parcel Subdivision EXCAVATOR: JustDiglt CLIENT: Lasher Enterprises DATE: 1/3I/20 GE 0 T E K LOCATION: Southwest of the N McDermott Rd and W Lazy Diamond C Ln ELEVATION: SAMPLES s TEST PIT NUMBER: TP-6 41 REMARKS aai a a N = G c H V H rn m 7 MATERIAL DESCRIPTION AND COMMENTS FILL Dk. Brown to Brown,SILT with Sand, Moist So Roots/Organics to 1.0' I — ML Dk. Brown to Brown,SILT with Sand, Moist F 2 — GP Brown to Lt. Brown, Poorly graded GRAVEL with Sand,Slightly Moist VD Percolation Test Conducted 3 — at 2.5' 4 — 5 — Tan 6 — 7 — 8 — 9 — Groundwater Depth at 8.8' Saturated per 2/3/20 Measurement 10 — 1 1 — END OF TEST PIT @ 1 1.0' 12 — 13 — 14 — 15 — 16 — 17— 18 — 19 — 20 320 E. Corporate Drive,Suite 300, Meridian, Idaho 83642 1 Office: (208)888-7010 Fax: (208)888-7924 APPENDIX C GeoTek, Inc. FIELD TESTS AND OBSERVATIONS (2097-ID) PERCOLATION TESTS The infiltration rate was determined by conducting percolation tests for onsite earth materials.The infiltration rate was determined in inches per hour in general accordance with the City of Meridian requirements. Infiltration rate results are presented below.The infiltration rates provided below should be used for design and not exceeded. LOCATION INFILTRATION RATE (Inches/Hour) TP-I @ 5.0' 24.0+ TP-2 @ 3.5' 3.3 TP-3 @ 4.0' 24.0+ TPA @ 2.0' 3.1 TP-5 @ 5.0' 24.0+ TP-6 @ 2.5' 24.0+ GROUND WATER MONITORING RESULTS Ground water monitoring results are presented below. Ground water elevation results are recorded in feet below existing grade. STAND-PIPE TP-I TP-2 TP-3 TP-4 TP-5 TP-6 PIEZOMETER# 12/16/19 8.1' 7.9' 7.3' 7.5' 7.8' 8.8' + Indicates a dry reading at the bottom of the piezometer n/a Indicates that the piezometer was damaged/missing in the field and no measurements were obtained. GeoTek, Inc. APPENDIX D GeoTek, Inc. LABORATORY TESTS RESULTS (2097-ID) ATTERBERG LIMITS Atterberg limits were performed on representative samples in general accordance with ASTM D 43 18. The results are shown in the following plates. PARTICLE SIZE ANALYSIS Sieve analyses were performed in general accordance with ASTM test method C 136 and ASTM C 1 17. Test results are presented in the following plates. RESISTANCE R-VALUE AND EXPANSION PRESSURE OF COMPACTED SOILS Tests were conducted on representative soil samples, in general accordance with Idaho test method T-8 and AASHTO T-190, to determine the soil's performance when placed in the base, subbase, or subgrade of a road subjected to traffic. LOCATION R-VALUE @ 200 psi TP-4 10 GeoTek, Inc. GeoTek-Idaho 320 Corporate Drive,Ste#300 7950 Meadowlark Way, Ste E Meridian, ID 83642 Coeur d'Alene, ID 83815 Phone: (208)888-7010 (208)888-7924 Fax: (208)904-2980 (208)904-2981 Report No: MAT:20-00611-S01 Material Test Report Client: Lasher Enterprises CC: 3327 N Eagle Road Meridian ID 83642 Project: 2097-ID Spriggle Parcel Subdivision GEO THIS DOCUMENT SHALL NOT BE REPRODUCED EXCEPT IN FULL Sample Details Atterberg Limit: Sample ID 20-00611-SO 1 Liquid Limit: N/A Date Sampled 1/31/2020 Plastic Limit: NP Specification General Sieve Set Location TP-2, 3.0'-4.0' Plasticity Index: NP Sample Description: _ SM, Silty SAND Particle Size Distribution Grading: ASTM C 136,ASTM C 117MM Date Tested: Tested By: %Passing Sieve Size % Passing Limits 90 ............... ............... ......................................... 2in 100 13/4in 100 80 ...................................... .................................. 1in 100 3/in 100 To .............................................. .......................... '/zin 100 3/8in 100 60 ...................................................... .................. No.4 97 N o.8 88 eo ............................................................. .......... No.16 78 40 .................................................................... .... No.30 69 N o.50 60 30 ......................................................................... No.100 50 No.200 38 20 ......................................................................... 10 ......................................................................... 0 _ a m �o 0 0 0 0 �� \ \ W O O M ifJ O N M Z Z Z Z Z O O Z Z Sieve COBBLES GRAVEL SAND FINES(38.0%) D85: 1.9169 D60: 0.3000 D50: 0.1500 Coarse Fine Coarse Medium Fine Silt Clay D30: N/A D15: N/A D10: N/A (0.0%) (0.0%) (3.0%) (11.4%) (21.1%) (26.5%) y Form No:18909,Report No:MAT:20-00611-S01 ©2000-2018 QESTLab by SpectraQEST.com Page 1 of 2 GeoTek-Idaho 320 Corporate Drive,Ste#300 7950 Meadowlark Way, Ste E Meridian, ID 83642 Coeur d'Alene, ID 83815 Phone: (208)888-7010 (208)888-7924 Fax: (208)904-2980 (208)904-2981 Report No: MAT:20-0061 1-S02 Material Test Report Client: Lasher Enterprises CC: 3327 N Eagle Road Meridian ID 83642 Project: 2097-ID Spriggle Parcel Subdivision GEO THIS DOCUMENT SHALL NOT BE REPRODUCED EXCEPT IN FULL Sample Details Atterberg Limit: Sample ID 20-00611-S02 Liquid Limit: 32 Date Sampled 1/31/2020 Plastic Limit: 25 Specification General Sieve Set Location TP-4, 1.0'-2.0' Plasticity Index: 7 Sample Description: _ ML, SILT w/Sand Particle Size Distribution Grading: ASTM C 136,ASTM C 117MM Date Tested: Tested By: %Passing Sieve Size % Passing Limits 90 ....................................................... ................ 2in 100 13/4in 100 80 .................................................................. ..... 1in 100 3/in 100 To ......................................................................... '/2in 100 3/8in 100 60 ......................................................................... N o.4 100 N o.8 100 eo ........................................................................ No.16 99 40 ......................................................................... No.30 96 No.50 91 30 ......................................................................... No.100 85 No.200 77 20 ......................................................................... 10 ......................................................................... 0 _ a m �o 0 0 0 0 �� \ \ W O O M ifJ O N M Z Z Z Z Z O O Z Z Sieve COBBLES GRAVEL SAND FINES(77.0%) D85: 0.1500 D60: N/A D50: N/A Coarse Fine Coarse Medium Fine Silt ClayD30: N/A D15: N/A D10: N/A (0.0%) (0.0%) (0.0%) (0.2%) (6.2%) (16.5%) Form No:18909,Report No:MAT:20-00611-S02 ©2000-2018 QESTLab by SpectraQEST.com Page 1 of 2 nd C fan - e W All SITE TP 4J O _ E L u ' - f r Z APPROXIMATETEST PIT LOCATIONS Source:Google Earth 2019, GeoTek Field Observations, 2020. Not to Scale FIGURE 2 SITE EXPLORATION PLAN Spriggle Parcel Subdivision SWC of the N McDermott Rd &W Lazy Diamond C Ln Intersection GGOTEK Meridian, Idaho GEOTECHNICAL I ENVIRONMENTAL I MATERIALS Prepared for: Lasher Enterprises Project No.: Report Date: Drawn By: 320 E.Corporate Dr,Suite 300, Meridian,ID 83642 2097-ID October 2020 TSL (208)888-7010(phone)/(208)888-7924(FAX) 2097-ID Spriggle Parcel Subdivision TP-I TP-2 TP-3 TP-4 TP-5 TP-6 comments 1/24/20 8.1' 7.9' 7.3' 7.5' 7.8' 8.8' KEY 3/20/20 8.7' 8.4' 7.8' 8.0' 8.6' 9.3' "+" Indicates dry reading at bottom of 4/24/20 8.8' 8.7' 8.0' 8.2' 8.6' 9.4' piezometer 5/8/20 8.5' 8.4' 7.8' 8.0' 8.3' 9.0' 5/21/20 7.9' 7.7' 7.4' 7.4' 8.3' 8.6' "N/A" Indicates that piezometer is damaged or missing-therefore no data was 6/4/20 7.1' 7.1' 7.0' 7.0' 7.1' 7.5' obtained 6/1 8/20 6.5' 6.5' 6.7' 6.6' 6.5' 6.9' 7/6/20 6.8' 6.6' 6.4' 6.2' 6.3' 6.5' 7/2 1/20 7.0' 6.7' 6.2' 6.4' 6.1' 6.1' 8/3/20 4.5' 4.6' 5.8' 5.5' 5.0' 5.0' Irrigation on adjacent corn field 8/2 1/20 4.9' 5.0' 6.1' 5.6' 6.2' 5.4' 9/3/20 5.1' 4.5' 5.9' 5.4' 5.0' 5.0' 9/1 8/20 5.0' 4.7' 5.6' 5.5' 4.8' 5.1' 10/1/20 5.8' 5.8' 6.1' 6.0' 6.0' 6.4' Note: Groundwater elevation results are recorded in feet below approximate existing grade. Generally,irrigation ditches and canals will locally influence ground water during the irrigation season.