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Railway Road Development - Geotechnical Report GEOTECHNICAL REPORT Railway Road Development 16314 and 16330 Railway Road Southeast Yelm, Washington Project No. T-8777 Prepared for: Blue Fern Development, LLC Redmond, Washington February 28, 2023 2-28-2023 TABLE OF CONTENTS Page No. 1.0 Project Description .......................................................................................................... 1 2.0 Scope of Work ................................................................................................................ 1 3.0 Site Conditions ................................................................................................................ 2 3.1 Surface ............................................................................................................... 2 3.2 Soils .................................................................................................................... 2 3.3 Groundwater ...................................................................................................... 3 3.4 Geologic Hazards ............................................................................................... 3 3.4.1 Erosion Hazard Areas ............................................................................... 4 3.4.2 Landslide Hazard Areas ............................................................................ 4 3.4.3 Seismic Hazard Areas ............................................................................... 5 3.5 Seismic Site Class .............................................................................................. 6 4.0 Discussion and Recommendations .................................................................................. 6 4.1 General ............................................................................................................... 6 4.2 Site Preparation and Grading ............................................................................. 6 4.3 Excavations ........................................................................................................ 7 4.4 Foundations ........................................................................................................ 7 4.5 Floor Slabs ......................................................................................................... 9 4.6 Lateral Earth Pressures for Wall Design ............................................................ 9 4.7 Infiltration Feasibility ...................................................................................... 10 4.8 Drainage ........................................................................................................... 10 4.9 Utilities ............................................................................................................. 11 4.10 Pavements ........................................................................................................ 11 5.0 Additional Services ....................................................................................................... 12 6.0 Limitations .................................................................................................................... 12 Figures Vicinity Map ........................................................................................................................ Figure 1 Exploration Location Plan ................................................................................................... Figure 2 Groundwater Levels ............................................................................................................. Figure 3 Typical Wall Drainage Detail .............................................................................................. Figure 4 Appendices Field Exploration and Laboratory Testing .................................................................... Appendix A Infiltration Letter ........................................................................................................... Appendix B Geotechnical Report Railway Road Development 16314 and 16330 Railway Road Southeast Yelm, Washington 1.0 PROJECT DESCRIPTION The project consists of developing the property with 90 residential building lots, a stormwater bioretention pond, and associated access and utilities. Based on the “Preliminary Grading Plan” prepared by CORE Design dated February 7, 2023, grading to achieve building lot and roadway grades will consist of cuts and fills from one to two feet. Site stormwater will be collected and directed to a stormwater bioretention pond in the western portion of the site. The pond will be formed by excavating below current site grades. The excavation required to achieve the pond floor elevation of 335.0 feet will extend approximately 6 feet below grade. An additional excavation of approximately 3 feet will be required to install the bioretention soil mix which has a bottom elevation of 332.25 feet. We expect that the residential structures constructed at the site will be two- to three-story, wood-framed buildings with their main floor levels constructed at grade. Structural loading should be relatively light with bearing walls carrying loads of 2 to 3 kips per foot and isolated columns carrying maximum loads of 30 to 40 kips. The recommendations contained in the following sections of this report are based on the above design features. If actual features vary or changes are made, we should review them in order to modify our recommendations, as required. We should review the final design drawings and specifications to verify our recommendations have been properly interpreted and incorporated into project design and construction. 2.0 SCOPE OF WORK Our work was completed in accordance with our proposal, dated June 14, 2022. Accordingly, on August 17, 2022, through August 19, 2022, we observed soil and groundwater conditions at 5 test borings drilled to maximum depths of approximately 25 feet below current site grades, and at 15 test pits excavated with a mini-excavator to maximum depths of approximately 8 to 12 feet below current site grades. On January 3, 2023, we supplemented this data by completing a pilot infiltration test in the proposed bioretention pond area. Using the information obtained from this subsurface exploration, we performed analyses to develop geotechnical recommendations for development at the site. Specifically, this report addresses the following:  Soil and groundwater conditions.  Geologic hazards per the City of Yelm Municipal Code.  Seismic design parameters per the current International Building Code (IBC). February 28, 2023 Project No. T-8777 Page No. 2  Site preparation and grading.  Excavations.  Foundations.  Slab-on-grade floors.  Lateral earth pressures for wall design.  Infiltration feasibility.  Drainage.  Utilities.  Pavements. It should be noted, recommendations outlined in this report regarding drainage are associated with soil strength, design earth pressures, erosion, and stability. Design and performance issues with respect to moisture as it relates to the structure environment are beyond Terra Associates, Inc.’s purview. A building envelope specialist or contractor should be consulted to address these issues, as needed. 3.0 SITE CONDITIONS 3.1 Surface The site consists of two tax parcels totaling approximately 14.89 acres located 16314 and 16330 Railway Road Southeast in Yelm, Washington. The approximate location of the site is shown on Figure 1. The site is currently developed with two single-family residences, several outbuildings, and associated access and landscaping in the southeast portion of the site. A small number of small- to medium-sized tree are located around the residential structure as well. The remainder of the site is predominantly undeveloped and appears to have been used for agricultural purposes. Site topography is relatively flat with no obvious signs of sloping. 3.2 Soils The site soils generally consist of approximately 2 to 24 inches of topsoil overlying native outwash deposits comprised predominantly of medium dense to very dense gravel and sand with varying silt and cobble contents to the termination of the test pits and test borings. The Geologic Map of Washington – Southwest Quadrant, by T.J. Walsh, M.A. Korosec, W.M. Phillips, R.L. Logan, and H.W. Schasse (1987) maps the site as recessional outwash gravel (Qgog) and is known locally as Steilacoom Gravel. This map unit is consistent with the native soils observed in the test pits and test borings. February 28, 2023 Project No. T-8777 Page No. 3 The United States Department of Agriculture Natural Resources Conservation Service (NRCS) classifies the onsite soils as Spanaway, gravelly sandy loam material. A soil horizon, consisting of this material, is typically deposited by glacial processes in the form of terraces and outwash plains, and is derived from volcanic ash over gravelly outwash which is consistent with our exploratory findings and knowledge of the area’s geologic setting. The preceding discussion is intended to be a brief review of the soil conditions observed at the site. More detailed descriptions are presented on the Test Pit and Test Boring Logs attached in Appendix A. The approximate location of the test pits and test borings is shown on attached Figure 2. 3.3 Groundwater We did not observe any groundwater seepage in the test pits. However, groundwater seepage was observed in the test borings at approximately 23 feet below existing site grades as well as minor perched seepage in Test Boring B- 1 at a depth of approximately 18 feet below site grades. The observed seepage in the test borings is interpreted to be indicative of the regional groundwater table associated with the Nisqually River Valley. We expect groundwater levels and flow rates will fluctuate seasonally and will typically reach their highest levels during, and shortly following, the wet winter months (November through May). Given the time of year our field work was completed, and our experience with groundwater conditions in the area, the groundwater levels observed likely represent near seasonal low levels. To evaluate the seasonal weather influence, the test borings were converted to groundwater monitoring wells. The monitoring wells will be instrumented with automatic level loggers in November 2022 to allow for winter groundwater monitoring through the 2022-2023 wet season. Groundwater levels in the monitoring wells were measured following their installation. The results of our measurements, showing depth to groundwater in feet, are shown in the table below: Date B-1 B-2 B-3 B-4 B-5 8-19-2022 22.95 ft 22.89 ft 23.02 ft 23.68 ft 23.27 ft 11-21-2022 25.1 ft 24.7 ft 24.8 ft 24.5 ft 24.7 ft 1-25-203 21.4 ft 21.7 ft 21.1 ft 22.3 ft 22.1 ft A graph showing the groundwater readings for the level loggers through January 24, 2023, is attached as Figure 3. 3.4 Geologic Hazards Chapter 18.21.100.A of the City of Yelm Municipal Code (YMC) defines geologically hazardous areas as being “…areas susceptible to erosion, sliding, earthquake, or other geological events. They pose a threat to the health and safety of citizens when incompatible development is sited in areas of significant hazard. Such incompatible development may not only place itself at risk, but also may increase the hazard to surrounding development and use.” Discussions related to erosion, landslide, mine, volcanic, and seismic hazards are presented below. February 28, 2023 Project No. T-8777 Page No. 4 3.4.1 Erosion Hazard Areas Chapter 18.21.100.B.1 of the YMC defines erosion hazard areas as areas that “…areas identified by the U.S. Department of Agriculture’s Natural Resources Conservation Service as having a “moderate to severe,” “severe,” or “very severe” rill and inter-rill erosion hazard. Rill or inter-rill are areas subject to sheet wash, or steep-sided channels resulting from accelerated erosion. Erosion hazard areas are also those areas impacted by shoreland and/or streambank erosion and those areas within a river’s channel migration zone.” We did not observe any indication of erosion or sediment deposition at the site. The site soils are mapped as Spanaway gravelly sandy loam, 0 to 3 percent slopes, by the United States Department of Agriculture Natural Resources Conservation Service (NRCS). Over the site with existing slope gradients, these soils will have a slight potential for erosion when exposed. Therefore, the site would not be classified as an erosion hazard per the YMC. Regardless, the site soils would be susceptible to some erosion when exposed during construction. Proper implementation and maintenance of Best Management Practices (BMPs) for erosion prevention and sediment control would adequately mitigate the erosion potential in the planned development area in our opinion. Erosion protection measures as required by the City of Yelm will need to be in place prior to and during grading activities at the site. 3.4.2 Landslide Hazard Areas Chapter 18.21.100.B.2 of the YMC defines landslide hazard areas as “…areas potentially subject to landslides based on a combination of geologic, topographic, and hydrologic factors. They include areas susceptible because of any combination of bedrock, soil, slope (gradient), slope aspect, structure, hydrology, or other factors. Examples of these may include, but are not limited to, the following: a. Areas of historic failures; b. Areas with all three of the following characteristics: i. Slopes steeper than 15 percent; ii. Hillsides intersecting geologic contacts with a relatively permeable sediment overlying a relatively impermeable sediment or bedrock; and iii. Springs or ground water seepage; c. Areas that have shown movement during the Holocene epoch (from 10,000 years ago to the present) or that are underlain or covered by mass wastage debris of that epoch; d. Slopes that are parallel or subparallel to planes of weakness (such as bedding planes, joint systems, and fault planes) in subsurface materials; February 28, 2023 Project No. T-8777 Page No. 5 e. Slopes having gradients steeper than 80 percent, subject to rock fall during seismic shaking; f. Areas potentially unstable because of rapid stream incision, streambank erosion, and undercutting by wave action; g. Areas that show evidence of or are at risk from snow avalanches; h. Areas located in a canyon or on an active alluvial fan, presently or potentially subject to inundation by debris flows or catastrophic flooding; and i. Any area with a slope of 40 percent or steeper and with a vertical relief of 10 or more feet, except areas composed of consolidated rock. A slope is delineated by establishing its toe and top and is measured by averaging the inclination over at least 10 feet of vertical relief.” The site is relatively flat with no obvious signs of sloping and none of the above conditions are present at the site. Therefore, it is our opinion that a landslide hazard does not exist at the site. 3.4.3 Seismic Hazard Areas Chapter 18.21.100.B.3 of the YMC defines seismic hazard areas as “… areas subject to severe risk of damage as a result of earthquake induced ground shaking, slope failure, settlement, soil liquefaction, lateral spreading, or surface faulting. One indicator of potential for future earthquake damage is a record of earthquake damage in the past. Ground shaking is the primary cause of earthquake damage in Washington. The strength of ground shaking is primarily affected by: a. The magnitude of an earthquake; b. The distance from the source of an earthquake; c. The type of thickness of geologic materials at the surface; and d. The type of subsurface geologic structure.” A review of a map titled Faults and Earthquakes in Washington State, dated 2014 by Jessica L. Czajkowski and Jeffrey D. Bowman shows the site does not reside within any active fault zone. The nearest fault, known as the Olympia Structure, is categorized as “Class B” and is located approximately 4.7 miles southwest of the site. Accordingly, during a seismic event, the risk of ground rupture along a fault line at the site is low. Liquefaction is a phenomenon where there is a reduction or complete loss of soil strength due to an increase in water pressure induced by vibrations. Liquefaction mainly affects geologically recent deposits of fine-grained sands underlying the groundwater table. Soils of this nature derive their strength from intergranular friction. The generated water pressure or pore pressure essentially separates the soil grains and eliminates this intergranular friction; thus, eliminating the soil’s strength. February 28, 2023 Project No. T-8777 Page No. 6 The predominant gravel and sand formation below the groundwater table at the site exhibits relatively high permeability and would allow dissipation of pore water pressures generated by a seismic event, thereby not significantly impacting the effective strength of the deposit. Therefore, it is our opinion that the risk for soil liquefaction to occur at this site and its associated impacts is low. 3.5 Seismic Site Class Based on soil conditions observed in the test pits, and our knowledge of the area geology, per Chapter 16 of the 2018 International Building Code (IBC), Site Class “D” should be used in structural design. 4.0 DISCUSSION AND RECOMMENDATIONS 4.1 General In our opinion, there are no geotechnical conditions that would preclude the planned development. The residential buildings can be supported on conventional spread footings bearing on competent native soils below the organic topsoil layer or on structural fill placed above the competent native soils. Floor slabs and pavements can be similarly supported. The native silty gravels located in the upper approximately four to seven feet of soil typically contain a sufficient amount of soil fines that will make it difficult to compact as structural fill when too wet. The ability to use these soils from site excavations as structural fill will depend on its moisture content and the prevailing weather conditions at the time of construction. The relatively clean outwash sand and gravel observed below these upper soils have a low percentage of soil fines and should be suitable for use as structural fill in most weather conditions. The availability of the relatively clean outwash soils may be limited due to site grading requirements. If there is insufficient sand and gravel available, the contractor should be prepared to import free-draining granular material for use as structural fill and backfill during the wet season. Detailed recommendations regarding these issues and other geotechnical design considerations are provided in the following sections. These recommendations should be incorporated into the final design drawings and construction specifications. 4.2 Site Preparation and Grading To prepare the site for construction, all vegetation, organic surface soils, and other deleterious material should be stripped and removed from the site. Surface stripping depths of approximately 2 to 24 inches should be expected to remove the organic surface soils and vegetation. In the developed portions of the site, demolition of existing structures should include removal of existing foundations and buried asphalt and abandonment of underground septic systems and other buried utilities. Abandoned utility pipes that fall outside of new building areas can be left in place provided they are sealed to prevent intrusion of groundwater seepage and soil. Organic topsoil will not be suitable for use as structural fill but may be used for limited depths in nonstructural areas. February 28, 2023 Project No. T-8777 Page No. 7 Once clearing and stripping operations are complete, cut and fill operations can be initiated to establish desired building grades. Prior to placing fill, all exposed bearing surfaces should be observed by a representative of Terra Associates, Inc. to verify soil conditions are as expected and suitable for support of new fill or building elements. Our representative may request a proofroll using heavy rubber-tired equipment to determine if any isolated soft and yielding areas are present. If excessively yielding areas are observed and they cannot be stabilized in place by compaction, the affected soils should be excavated and removed to firm bearing and grade restored with new structural fill. If the depth of excavation to remove unstable soils is excessive, the use of geotextile fabrics such as, Mirafi 500X or an equivalent fabric can be used in conjunction with cl ean granular structural fill. Our experience has shown, in general, a minimum of 18 inches of a clean, granular structural fill placed and compacted over the geotextile fabric should establish a stable bearing surface. Our study indicates that the native silty gravel soils encountered in the upper four to seven feet of the site contain a sufficient amount of soil fines that will make them difficult to compact as structural fill when too wet or too dry. The ability to use these soils from site excavations as structural fill will depend on its moisture content, the prevailing weather conditions at the time of construction and the contractor’s ability to compact the native silt soils. If wet soils are encountered, the contractor will need to dry the soils by aeration during dry weather conditions. Alternatively, the use of an additive, such as Portland cement or lime to stabilize the soil moisture can be considered. If the soil is amended, additional Best Management Practices (BMPs) addressing the potential for elevated pH levels will need to be included in the Stormwater Pollution Prevention Program (SWPPP) prepared with the Temporary Erosion and Sedimentation Control (TESC) plan. The relatively clean gravels observed throughout the site, should be suitable to reuse as structural fill in most weather conditions. If grading activities are planned during the wet winter months, or if they are initiated during the summer and extend into fall and winter, the owner should be prepared to import wet-weather structural fill. For this purpose, we recommend importing a granular soil that meets the following grading requirements: U.S. Sieve Size Percent Passing 6 inches 100 No. 4 75 maximum No. 200 5 maximum* *Based on the 3/4-inch fraction. Prior to use, Terra Associates, Inc. should examine and test all materials imported to the site for use as structural fill. Structural fill should be placed in uniform loose layers not exceeding 12 inches and compacted to a minimum of 95 percent of the soil’s maximum dry density, as determined by American Society for Testing and Materials (ASTM) Test Designation D-1557 (Modified Proctor). The moisture content of the soil at the time of compaction should be within two percent of its optimum, as determined by this ASTM standard. In nonstructural areas, the degree of compaction can be reduced to 90 percent. February 28, 2023 Project No. T-8777 Page No. 8 4.3 Excavations All excavations at the site associated with confined spaces, such as those for utility construction, must be completed in accordance with local, state, or federal requirements. Based on current Washington Industrial Safety and Health Act (WISHA) regulations, the site’s soils would be classified as Type C soils. Accordingly, temporary excavations in Type C soils should have their slopes laid back at an inclination of 1.5:1 (Horizontal: Vertical) or flatter, from the toe to the crest of the slope. If there is insufficient space to complete the excavations in this manner, or if excavations greater than 20 feet in depth are planned, then temporary shoring to support the excavations may be required. Properly designed and installed shoring trench boxes can be used to support utility trench excavations where required. Our explorations indicate that the contractor should be prepared to excavate into abundant cobbles and occasional boulders. We were able to excavate through the cobbles and boulders for the test pits, but the test pits are limited in size. Larger excavations and utility excavations may impacted by the cobbles and boulders. Additionally, as observed during our explorations, pockets of cobbles or boulders may become loose and present a caving hazard during excavation procedures. This information is provided solely for the benefit of the owner and other design consultants and should not be construed to imply that Terra Associates, Inc. assumes responsibility for job site safety. It is understood that job site safety is the sole responsibility of the project contractor. 4.4 Foundations The residential buildings may be supported on conventional spread footing foundations bearing on competent native soils or on structural fill placed above competent native soils. Foundation subgrades should be prepared as recommended in Section 4.2 of this report. Foundations exposed to the weather should bear at a minimum depth of 1.5 feet below adjacent exterior grades for frost protection. Interior foundations should be supported at a minimum depth of one foot below the finished floor elevation. We recommend designing foundations bearing on competent soils for a net allowable bearing capacity of 2,500 psf. For short-term loads, such as wind and seismic, a one-third increase in this allowable capacity can be used. With the expected building loads and this bearing stress applied, in general, total, and differential settlements should not exceed one inch and one-half inch, respectively. For designing foundations to resist lateral loads, a base friction coefficient of 0.35 can be used. Passive earth pressures acting on the sides of the footings should be considered. We recommend calculating this lateral resistance using an equivalent fluid weight of 300 pounds per cubic foot (pcf). We do not recommend including the upper 12 inches of soil in this computation because it can be affected by weather or disturbed by future grading activity. This value assumes the foundation will be backfilled with structural fill, as described in Section 4.2 of this report. The values recommended include a safety factor of 1.5. February 28, 2023 Project No. T-8777 Page No. 9 4.5 Slab-on-Grade Floors Slab-on-grade floors may be supported on subgrade prepared as recommended in Section 4.2 of this report. Immediately below the floor slabs, we recommend placing a four-inch-thick capillary break layer of clean, free- draining, coarse sand or fine gravel that has less than five percent passing the No. 200 sieve. This material will reduce the potential for upward capillary movement of water through the underlying soil and subsequent wetting of the floor slabs. Installation of a capillary break layer will not be necessary where the floor subgrade is composed of the clean native outwash or structural fill comprised of the clean outwash. A representative of Terra Associates should observe the subgrade at the time of construction to verify it’s condition and determine if an imported capillary break layer is required. The capillary break layer will not prevent moisture intrusion through the slab caused by water vapor transmission. Where moisture by vapor transmission is undesirable, such as covered floor areas, a common practice is to place a durable plastic membrane on the capillary break layer, then cover the membrane with a layer of clean sand or fine gravel to protect it from damage during construction and aid in uniform curing of the concrete slab. It should be noted, if the sand or gravel layer overlying the membrane is saturated prior to pouring the slab, it will be ineffective in assisting in uniform curing of the slab and can actually serve as a water supply for moisture transmission through the slab and affecting floor coverings. Therefore, in our opinion, covering the membrane with a layer of sand or gravel should be avoided if floor slab construction occurs during the wet winter months and the layer cannot be effectively drained. We recommend floor designers and contractors refer to the current American Concrete Institute (ACI) Manual of Concrete Practice for further information regarding vapor barrier installation below slab-on-grade floors. 4.6 Lateral Earth Pressures for Below-Grade Walls The magnitude of earth pressure development on below-grade walls will partly depend on the quality of the wall backfill. We recommend placing and compacting wall backfill as structural fill as described in Section 4.2 of this report. To prevent overstressing the walls during backfilling, heavy construction machinery should not be operated within five feet of the wall. Wall backfill in this zone should be compacted with hand-operated equipment. To guard against hydrostatic pressure development, wall drainage must also be installed. A typical recommended wall drainage detail is shown on Figure 4. With wall backfill placed and compacted as recommended and drainage properly installed, we recommend designing unrestrained walls for an active earth pressure equivalent to a fluid weighing 35 pcf. For restrained walls, an active earth pressure equivalent to a fluid weighing 50 pcf may be used. To account for typical traffic surcharge loading, the walls can be designed for an additional imaginary height of two feet (two-foot soil surcharge). For evaluation of wall performance under seismic loading, a uniform pressure equivalent to 8H psf, where H is the height of the below-grade portion of the wall should be applied in addition to the static lateral earth pressure. These values assume a horizontal backfill condition and no other surcharge loading, sloping embankments, or adjacent buildings will act on the wall. If such conditions exist, then the imposed loading must be included in the wall design. Friction at the base of foundations and passive earth pressure will provide resistance to these lateral loads. Values for these parameters are provided in Section 4.4 of this report. February 28, 2023 Project No. T-8777 Page No. 10 4.7 Infiltration Feasibility Site stormwater is proposed to be collected and directed to a bioretention facility in the western portion of the site. Based on the soil conditions observed, it is our opinion that the outwash gravels contain relatively low fines contents and will support infiltration of project stormwater. Groundwater seepage was observed at a depth of approximately 23 feet below existing site grades in August 2022 and approximately 21 feet below current site grades in January 2023. A minimum separation distance of three feet must be maintained between the seasonal high groundwater and the bottom of the infiltration facility. Currently the bottom of the proposed facility is at elevation 332.25 feet which is approximately 8.75 feet below current site grades. With groundwater approximately 21 feet below current site grades there is approximately 12 feet between the bottom of the facility and the seasonal high groundwater. In August 2022, in order to determine the site’s suitability for support of relatively shallow infiltration facilities, we completed one small-scale pilot infiltration tests (PIT) at depths of approximately seven feet below existing grades. The test was completed at the location of Test Pit TP-14. The Test Pit Log associated with the PIT location is included in Appendix A. The soils exposed at the bottom of the infiltration PITs consisted of medium dense gravel with sand. For the test, we filled the approximately 12 square-foot excavation with roughly 12 inches of water and ran an approximately two-hour steady-state soaking period followed by a falling head percolation test. After the two-hour soaking period, approximately 12 inches of water remained in the PIT excavation. The remaining water fully drained out of the excavation after approximately 6 minutes and 54 seconds. Based on the testing results and correction factors obtained from Table V-5.1 of the DOE 2019 Stormwater Management Manual for Western Washington, a preliminary long-term design infiltration rate of 15 inches per hour can be used. On January 3, 2023, we complete a small scale PIT in the vicinity of the proposed bioretention facility. The results of our testing indicated the long term design infiltration rate of 15 inches per hour was suitable for the site. The approximate location of the PIT is shown on Figure 2. The testing data is shown in our Infiltration Testing Letter dated February 7, 2023. This letter is attached in Appendix B. The permeability of the native outwash soils will be significantly impacted by the intrusion of soil fines (silt- and clay-sized particles). A relatively minor amount of soil fines can reduce the permeability of the formation by a factor of ten. The greatest exposure to soil fines contamination will occur during mass grading and construction. Therefore, we recommend that the Temporary Erosion and Sedimentation Control (TESC) plans route construction stormwater to a location other than the permanent infiltration facility. 4.8 Drainage Surface Final exterior grades should promote free and positive drainage away from the site at all times. Water must not be allowed to pond or collect adjacent to foundations or within the immediate building areas. We recommend providing a positive drainage gradient away from the building perimeters. If this gradient cannot be provided, then surface water should be collected adjacent to the structures and directed to appropriate storm facilities. February 28, 2023 Project No. T-8777 Page No. 11 Subsurface Considering the well-drained nature of the site soils, provided the finish floor grade is at or above the adjacent exterior grade and positive drainage away from the structure is maintained, in our opinion, perimeter foundation drains would not be required. 4.9 Utilities Utility pipes should be bedded and backfilled in accordance with American Public Works Association (APWA), or City of Yelm specifications. At a minimum, trench backfill should be placed and compacted as structural fill, as described in Section 4.2 of this report. The native sands and gravels should generally be suitable for use as backfill material. As noted, some of the surficial fill soils are moisture sensitive and close moisture control will be required to facilitate proper compaction. If utility construction takes place during the winter, it may be necessary to import suitable wet weather fill for utility trench backfilling. 4.10 Pavements Pavement subgrades should be prepared as described in Section 4.2 of this report. Regardless of the degree of relative compaction achieved, the subgrade must be firm and relatively unyielding before paving. The subgrade should be proofrolled with heavy rubber-tired construction equipment such as a loaded 10-yard dump truck to verify this condition. The pavement design section is dependent upon the supporting capability of the subgrade soils and the traffic conditions to which it will be subjected. For residential access, with traffic consisting mainly of light passenger vehicles with only occasional heavy traffic, and with a stable subgrade prepared as recommended, we recommend the following pavement sections:  Two inches of Hot Mix Asphalt (HMA) over four inches of Crushed Rock Base (CRB)  Three and one-half inches of full depth HMA The paving materials used should conform to the Washington State Department of Transportation (WSDOT) specifications for half-inch class HMA and CRB. Long-term pavement performance will depend upon surface drainage. A poorly-drained pavement section will be subject to premature failure as a result of surface water infiltrating into the subgrade soils and reducing their supporting capability. For optimum pavement performance, we recommend surface drainage gradients of at least two percent. Some degree of longitudinal and transverse cracking of the pavement surface should be expected over time. Regular maintenance should be planned to seal cracks when they occur. February 28, 2023 Project No. T-8777 Page No. 12 5.0 ADDITIONAL SERVICES Terra Associates, Inc. should review the final design drawings and specifications in order to verify that earthwork and foundation recommendations have been properly interpreted and implemented in project design. We should also provide geotechnical services during construction to observe compliance with our design concepts, specifications, and recommendations. This will allow for design changes if subsurface conditions differ from those anticipated prior to the start of construction. 6.0 LIMITATIONS We prepared this report in accordance with generally accepted geotechnical engineering practices. No other warranty, expressed or implied, is made. This report is the copyrighted property of Terra Associates, Inc. and is intended for specific application to the Railway Road Development project in Yelm, Washington. This report is for the exclusive use of Blue Fern Development, LLC, and their authorized representatives. The analyses and recommendations presented in this report are based on data obtained from the test pits excavated on the site. Variations in soil conditions can occur, the nature and extent of which may not become evident until construction. If variations appear evident, Terra Associates, Inc. should be requested to reevaluate the recommendations in this report prior to proceeding with construction. © 2022 Microsoft Corporation © 2022 TomTom SITE Environmental Earth Sciences Terra Associates, Inc. Consultants in Geotechnical Engineering Geology and Figure 1 VICINITY MAP 0 1000 2000 APPROXIMATE SCALE IN FEET REFERENCE: https://www.bing.com/maps ACCESSED 8/25/22 Proj.No. T-8777 Date: FEB 2023 YELM, WASHINGTON RAILWAY ROAD DEVELOPMENT TP-1B-1TP-2TP-3TP-4TP-5TP-6TP-7TP-8TP-9TP-10TP-11TP-13TP-13TP-15TP-14B-2B-3B-4B-4PIT-1REFERENCE:REFERENCE ONLY AND SHOULD NOT BE USED FORDESIGN OR CONSTRUCTION PURPOSES.DIMENSIONS ARE APPROXIMATE. IT IS INTENDED FORNOTE:THIS SITE PLAN IS SCHEMATIC. ALL LOCATIONS ANDConsultants in Geotechnical EngineeringTerraAssociates, Inc.Geology andEnvironmental Earth SciencesEXPLORATION LOCATION PLANFigure 2LEGEND:0100200APPROXIMATE SCALE IN FEETAPPROXIMATE BORING LOCATIONSITE PLAN PROVIDED BY BING MAPS.APPROXIMATE TEST PIT LOCATIONProj.No. T-8777Date: FEB 2023YELM, WASHINGTONRAILWAY ROAD DEVELOPMENTAPPROXIMATE PIT LOCATION 20.52121.52222.52323.52424.52525.511/26/22 12:00 AM 12/6/22 12:00 AM 12/16/22 12:00 AM 12/26/22 12:00 AM 1/5/23 12:00 AM 1/15/23 12:00 AM 1/25/23 12:00 AMGroundwater Depth Below Grade (feet)DateRailway Road Development ‐Groundwater LevelsB‐1B‐2B‐3B‐4B‐5Figure 3 12" COMPACTED STRUCTURAL FILL EXCAVATED SLOPE (SEE REPORT TEXT FOR APPROPRIATE INCLINATIONS) SLOPE TO DRAIN 12" MINIMUM 3/4" MINUS WASHED GRAVEL 3" BELOW PIPE 12" OVER PIPE 4" DIAMETER PERFORATED PVC PIPE SEE NOTE 6"(MIN.) NOT TO SCALE NOTE: MIRADRAIN G100N PREFABRICATED DRAINAGE PANELS OR SIMILAR PRODUCT CAN BE SUBSTITUTED FOR THE 12-INCH WIDE GRAVEL DRAIN BEHIND WALL. DRAINAGE PANELS SHOULD EXTEND A MINIMUM OF SIX INCHES INTO 12-INCH THICK DRAINAGE GRAVEL LAYER OVER PERFORATED DRAIN PIPE. Environmental Earth Sciences Terra Associates, Inc. Consultants in Geotechnical Engineering Geology and TYPICAL WALL DRAINAGE DETAIL Figure 4Proj.No. T-8777 Date: FEB 2023 YELM, WASHINGTON RAILWAY ROAD DEVELOPMENT Project No. T-8777 APPENDIX A FIELD EXPLORATION AND LABORATORY TESTING Railway Road Development Yelm, Washington On August 17, 2022 through August 19, 2022, we investigated subsurface conditions at the site by excavating 15 test pits with a mini-excavator to depths of approximately 8 to 12 feet below existing grades and drilled 5 test borings to maximum depths of approximately 25 feet below existing grades. The test pit and test boring locations were approximately determined in the field using GPS coordinates. The approximate test pit and test boring locations are shown on Figure 2. The Test Pit and Test Boring logs are presented as Figures A-2 through A-21. A geotechnical engineer from our office conducted the field exploration. Our representative classified the soil conditions encountered, maintained a log of each test boring, obtained representative soil samples, and recorded water levels observed during drilling. During drilling, continuous soil samples were obtained during drilling in general accordance with ASTM Test Designation D-6914. Using this procedure, an 8-inch (outside diameter) hollow coring barrel is vibrated into the subsurface at 2.5- to 5-foot intervals. A 2.5-foot, continuous section of soil is then emptied into a sampling bag. Soil samples were also obtained in general accordance with ASTM Test Designation D-1586. Using this procedure, a 2-inch (outside diameter) split barrel sampler is driven into the ground 18 inches using a 140-pound hammer free falling from a height of 30 inches. The number of blows required to drive the sampler 12 inches after an initial 6-inch set is referred to as the Standard Penetration Resistance value or N value. This is an index related to the consistency of cohesive soils and relative density of cohesionless materials. N values obtained for each sampling interval are recorded on the Test Boring Logs, Figures A-17 through A-21. All soil samples were visually classified in accordance with the Unified Soil Classification System (USCS) described on Figure A-1. Representative soil samples obtained from the test pits were placed in sealed plastic bags and taken to our laboratory for further examination and testing. The moisture content of each sample was measured and is reported on the Test Pit and Test Boring Logs. Grain size analyses were performed on select soil samples. The results are shown on Figures A-22 through A-27. Environmental Earth Sciences Terra Associates, Inc. Consultants in Geotechnical Engineering Geology and MAJOR DIVISIONS LETTER SYMBOL TYPICAL DESCRIPTION GRAVELS More than 50% of coarse fraction is larger than No. 4 sieve Clean Gravels (less than 5% fines) GW Well-graded gravels, gravel-sand mixtures, little or no fines. GP Poorly-graded gravels, gravel-sand mixtures, little or no fines. Gravels with fines GM Silty gravels, gravel-sand-silt mixtures, non-plastic fines. GC Clayey gravels, gravel-sand-clay mixtures, plastic fines. SANDS More than 50% of coarse fraction is smaller than No. 4 sieve Clean Sands (less than 5% fines) SW Well-graded sands, sands with gravel, little or no fines. SP Poorly-graded sands, sands with gravel, little or no fines. Sands with fines SM Silty sands, sand-silt mixtures, non-plastic fines. SC Clayey sands, sand-clay mixtures, plastic fines. SILTS AND CLAYS Liquid Limit is less than 50% ML Inorganic silts, rock flour, clayey silts with slight plasticity. CL Inorganic clays of low to medium plasticity. (Lean clay) OL Organic silts and organic clays of low plasticity. SILTS AND CLAYS Liquid Limit is greater than 50% MH Inorganic silts, elastic. CH Inorganic clays of high plasticity. (Fat clay) OH Organic clays of high plasticity. HIGHLY ORGANIC SOILS PT Peat.COARSE GRAINED SOILSMore than 50% material largerthan No. 200 sieve sizeFINE GRAINED SOILSMore than 50% material smallerthan No. 200 sieve sizeDEFINITION OF TERMS AND SYMBOLS COHESIONLESSCOHESIVE Standard Penetration Density Resistance in Blows/Foot Very Loose 0-4 Loose 4-10 Medium Dense 10-30 Dense 30-50 Very Dense >50 Standard Penetration Consistancy Resistance in Blows/Foot Very Soft 0-2 Soft 2-4 Medium Stiff 4-8 Stiff 8-16 Very Stiff 16-32 Hard >32 2" OUTSIDE DIAMETER SPILT SPOON SAMPLER 2.4" INSIDE DIAMETER RING SAMPLER OR SHELBY TUBE SAMPLER WATER LEVEL (Date) Tr TORVANE READINGS, tsf Pp PENETROMETER READING, tsf DD DRY DENSITY, pounds per cubic foot LL LIQUID LIMIT, percent PI PLASTIC INDEX N STANDARD PENETRATION, blows per foot UNIFIED SOIL CLASSIFICATION SYSTEM Figure A-1Proj.No. T-8777 Date: FEB 2023 YELM, WASHINGTON RAILWAY ROAD DEVELOPMENT Sample No.Depth (ft)PROJECT NAME:PROJ. NO:LOGGED BY: LOCATION: DATE LOGGED: APPROX. ELEV: DEPTH TO CAVING: FIGURE DEPTH TO GROUNDWATER: SURFACE CONDITIONS: Description Consistency/ Relative Density W (%)interpreted as being indicative of other locations at the site. NOTE: This subsurface information pertains only to this test pit location and should not be 0 1 2 3 4 5 6 7 8 9 10 11 12 13 A-2 T-8777 SLK Yelm, Washington Grass August 19, 2022 Railway Road Development LOG OF TEST PIT NO.TP-1 N/A N/A 5 to11 feet 2.4 6.0 4.6 Loose to Medium Dense Medium Dense Black silty SAND with gravel, fine to medium sand, fine to coarse gravel, moist, moderate organic inclusions. (TOPSOIL) (SM) Brown silty GRAVEL with sand, fine to medium sand, fine to coarse gravel, moist, numerous cobbles, some organics. (GM) Brown GRAVEL with sand, fine to coarse sand, fine to coarse gravel, moist, scattered cobbles. (GP) Brown GRAVEL with silt and sand, fine to coarse sand, fine to coarse gravel, moist, numerous cobbles. (GP-GM) Brown SAND with gravel, fine to coarse sand, fine to coarse gravel, moist, trace silt. (SP) Test pit terminated at approximately 11 feet. Slight to moderate caving observed from 5 to 11 feet. No groundwater seepage observed. Sample No.Depth (ft)PROJECT NAME:PROJ. NO:LOGGED BY: LOCATION: DATE LOGGED: APPROX. ELEV: DEPTH TO CAVING: FIGURE DEPTH TO GROUNDWATER: SURFACE CONDITIONS: Description Consistency/ Relative Density W (%)interpreted as being indicative of other locations at the site. NOTE: This subsurface information pertains only to this test pit location and should not be 0 1 2 3 4 5 6 7 8 9 A-3 T-8777 SLK Yelm, Washington Grass August 19, 2022 Railway Road Development LOG OF TEST PIT NO.TP-2 N/A N/A 3 to 8 feet 4.4 4.4 4.7 Loose to Medium Dense Medium Dense Black silty SAND with gravel, fine to medium sand, fine to coarse gravel, moist, moderate organic inclusions. (TOPSOIL) (SM) Brown GRAVEL with silt and sand, fine to coarse sand, fine to coarse gravel, moist, scattered cobbles. (GP-GM) Brown SAND with gravel, medium to coarse sand, fine to coarse gravel, moist, cobbles, trace silt. (SP) Test pit terminated at approximately 8 feet. Slight caving observed from 3 to 8 feet. No groundwater seepage observed. Sample No.Depth (ft)PROJECT NAME:PROJ. NO:LOGGED BY: LOCATION: DATE LOGGED: APPROX. ELEV: DEPTH TO CAVING: FIGURE DEPTH TO GROUNDWATER: SURFACE CONDITIONS: Description Consistency/ Relative Density W (%)interpreted as being indicative of other locations at the site. NOTE: This subsurface information pertains only to this test pit location and should not be 0 1 2 3 4 5 6 7 8 9 10 A-4 T-8777 SLK Yelm, Washington Grass August 19, 2022 Railway Road Development LOG OF TEST PIT NO.TP-3 N/A N/A 3 to 8.5 feet 3.1 4.6 6.8 Loose to Medium Dense Medium Dense Black silty SAND with gravel, fine to medium sand, fine to coarse gravel, moist, moderate organic inclusions. (TOPSOIL) (SM) Brown GRAVEL with sand, fine to coarse sand, fine to coarse gravel, moist, scattered cobbles. (GP-GM) Brown GRAVEL with silt and sand, fine to coarse sand, fine to coarse gravel, moist, scattered cobbles. (GP-GM) Brown SAND with gravel, fine to coarse sand, fine to coarse gravel, moist, trace silt. (SP) Test pit terminated at approximately 8.5 feet. Moderate caving observed from 3 to 8.5 feet. No groundwater seepage observed. Sample No.Depth (ft)PROJECT NAME:PROJ. NO:LOGGED BY: LOCATION: DATE LOGGED: APPROX. ELEV: DEPTH TO CAVING: FIGURE DEPTH TO GROUNDWATER: SURFACE CONDITIONS: Description Consistency/ Relative Density W (%)interpreted as being indicative of other locations at the site. NOTE: This subsurface information pertains only to this test pit location and should not be 0 1 2 3 4 5 6 7 8 9 A-5 T-8777 SLK Yelm, Washington Grass August 19, 2022 Railway Road Development LOG OF TEST PIT NO.TP-4 N/A N/A 0 to 3, 4 to 8 feet 5.7 4.0 4.7 Loose Medium Dense Black silty SAND with gravel, fine to medium sand, fine to coarse gravel, moist, moderate organic inclusions. (TOPSOIL) (SM) Brown GRAVEL with silt and sand, fine to coarse sand, fine to coarse gravel, moist, scattered cobbles. (GP-GM) Brown SAND with gravel, fine to coarse sand, fine to coarse gravel, moist, trace silt. (SP) Test pit terminated at approximately 8 feet. Heavy caving observed from 0 to 3 feet, moderate caving observed from 4 to 8 feet. No groundwater seepage observed. Sample No.Depth (ft)PROJECT NAME:PROJ. NO:LOGGED BY: LOCATION: DATE LOGGED: APPROX. ELEV: DEPTH TO CAVING: FIGURE DEPTH TO GROUNDWATER: SURFACE CONDITIONS: Description Consistency/ Relative Density W (%)interpreted as being indicative of other locations at the site. NOTE: This subsurface information pertains only to this test pit location and should not be 0 1 2 3 4 5 6 7 8 9 A-6 T-8777 SLK Yelm, Washington Grass August 19, 2022 Railway Road Development LOG OF TEST PIT NO.TP-5 N/A N/A 3 to 8 feet 2.6 3.4 3.0 Loose to Medium Dense Medium Dense Dark brown silty SAND with gravel, fine to medium sand, fine to coarse gravel, moist, moderate organic inclusions. (TOPSOIL) (SM) Brown GRAVEL with sand, fine to coarse sand, fine to coarse gravel, moist, scattered cobbles, trace silt. (GP) Brown SAND with gravel, fine to coarse sand, fine to coarse gravel, moist, trace silt. (SP) Test pit terminated at approximately 8 feet. Moderate caving observed from 3 to 8 feet. No groundwater seepage observed. Sample No.Depth (ft)PROJECT NAME:PROJ. NO:LOGGED BY: LOCATION: DATE LOGGED: APPROX. ELEV: DEPTH TO CAVING: FIGURE DEPTH TO GROUNDWATER: SURFACE CONDITIONS: Description Consistency/ Relative Density W (%)interpreted as being indicative of other locations at the site. NOTE: This subsurface information pertains only to this test pit location and should not be 0 1 2 3 4 5 6 7 8 9 10 11 12 A-7 T-8777 SLK Yelm, Washington Medium/Long Grass August 19, 2022 Railway Road Development LOG OF TEST PIT NO.TP-6 N/A N/A 6 to 10 feet 3.1 3.4 4.6 Loose to Medium Dense Medium Dense to Dense Medium Dense Black silty SAND with gravel, fine to medium sand, fine to coarse gravel, moist, moderate organic inclusions. (TOPSOIL) (SM) Brown GRAVEL with sand, fine to coarse sand, fine to coarse gravel, moist, scattered cobbles, trace silt. (GP) Brown-gray SAND with gravel, fine to coarse sand, fine to coarse gravel, moist, trace silt. (SP) Test pit terminated at approximately 10 feet. Moderate caving observed from 6 to 10 feet. No groundwater seepage observed. Sample No.Depth (ft)PROJECT NAME:PROJ. NO:LOGGED BY: LOCATION: DATE LOGGED: APPROX. ELEV: DEPTH TO CAVING: FIGURE DEPTH TO GROUNDWATER: SURFACE CONDITIONS: Description Consistency/ Relative Density W (%)interpreted as being indicative of other locations at the site. NOTE: This subsurface information pertains only to this test pit location and should not be 0 1 2 3 4 5 6 7 8 9 10 A-8 T-8777 SLK Yelm, Washington Medium/Long Grass August 19, 2022 Railway Road Development LOG OF TEST PIT NO.TP-7 N/A N/A 2 to 6 feet 3.3 5.4 5.0 Loose to Medium Dense Medium Dense Black silty SAND with gravel, fine to medium sand, fine to coarse gravel, moist, moderate organic inclusions. (TOPSOIL) (SM) Brown to gray GRAVEL with sand, fine to coarse sand, fine to coarse gravel, moist, scattered cobbles, trace silt. (GP) Test pit terminated at approximately 9 feet. Slight caving observed from 2 to 6 feet. No groundwater seepage observed. Sample No.Depth (ft)PROJECT NAME:PROJ. NO:LOGGED BY: LOCATION: DATE LOGGED: APPROX. ELEV: DEPTH TO CAVING: FIGURE DEPTH TO GROUNDWATER: SURFACE CONDITIONS: Description Consistency/ Relative Density W (%)interpreted as being indicative of other locations at the site. NOTE: This subsurface information pertains only to this test pit location and should not be 0 1 2 3 4 5 6 7 8 9 10 11 12 A-9 T-8777 SLK Yelm, Washington Medium/Long Grass August 19, 2022 Railway Road Development LOG OF TEST PIT NO.TP-8 N/A N/A 5.5 to 10 feet 4.3 4.3 7.0 Loose to Medium Dense Medium Dense Black silty SAND with gravel, fine to medium sand, fine to coarse gravel, moist, moderate organic inclusions. (TOPSOIL) (SM) Brown GRAVEL with silt and sand, fine to coarse sand, fine to coarse gravel, moist, scattered cobbles. (GP-GM) Brown SAND with gravel, fine to coarse sand, fine to coarse gravel, moist, trace silt. (SP) Test pit terminated at approximately 10 feet. Slight caving observed from 5.5 to 10 feet. No groundwater seepage observed. Sample No.Depth (ft)PROJECT NAME:PROJ. NO:LOGGED BY: LOCATION: DATE LOGGED: APPROX. ELEV: DEPTH TO CAVING: FIGURE DEPTH TO GROUNDWATER: SURFACE CONDITIONS: Description Consistency/ Relative Density W (%)interpreted as being indicative of other locations at the site. NOTE: This subsurface information pertains only to this test pit location and should not be 0 1 2 3 4 5 6 7 8 9 10 A-10 T-8777 SLK Yelm, Washington Medium/Long Grass August 19, 2022 Railway Road Development LOG OF TEST PIT NO.TP-9 N/A N/A 6 to 9 feet 3.2 3.4 5.0 Loose to Medium Dense Medium Dense Black silty SAND with gravel, fine to medium sand, fine to coarse gravel, moist, moderate organic inclusions. (TOPSOIL) (SM) Brown to gray GRAVEL with sand, fine to coarse sand, fine to coarse gravel, moist, scattered cobbles, trace sand. (GP) Test pit terminated at approximately 9 feet. Moderate caving observed from 6 to 9 feet. No groundwater seepage observed. Sample No.Depth (ft)PROJECT NAME:PROJ. NO:LOGGED BY: LOCATION: DATE LOGGED: APPROX. ELEV: DEPTH TO CAVING: FIGURE DEPTH TO GROUNDWATER: SURFACE CONDITIONS: Description Consistency/ Relative Density W (%)interpreted as being indicative of other locations at the site. NOTE: This subsurface information pertains only to this test pit location and should not be 0 1 2 3 4 5 6 7 8 9 10 11 12 13 A-11 T-8777 SLK Yelm, Washington Medium/Long Grass August 19, 2022 Railway Road Development LOG OF TEST PIT NO.TP-10 N/A N/A 1.5 to 5, 8 to 11.5 feet 2.6 4.4 5.2 4.7 Loose to Medium Dense Medium Dense Black silty SAND with gravel, fine to medium sand, fine to coarse gravel, moist, moderate organic inclusions. (TOPSOIL) (SM) Brown GRAVEL with sand, fine to coarse sand, fine to coarse gravel, moist, scattered cobbles. (GP) Brown-gray GRAVEL with silt and sand, fine to coarse sand, fine to coarse gravel, moist, scattered cobbles. (GP-GM) *Scattered boulders observed from 5 to 8 feet. Test pit terminated at approximately 11.5 feet. Slight caving observed from 1.5 to 5 feet, moderate caving observed from 8 to 11.5 feet. No groundwater seepage observed. Sample No.Depth (ft)PROJECT NAME:PROJ. NO:LOGGED BY: LOCATION: DATE LOGGED: APPROX. ELEV: DEPTH TO CAVING: FIGURE DEPTH TO GROUNDWATER: SURFACE CONDITIONS: Description Consistency/ Relative Density W (%)interpreted as being indicative of other locations at the site. NOTE: This subsurface information pertains only to this test pit location and should not be 0 1 2 3 4 5 6 7 8 9 10 A-12 T-8777 SLK Yelm, Washington Medium/Long Grass August 19, 2022 Railway Road Development LOG OF TEST PIT NO.TP-11 N/A N/A 4 to 9 feet 3.6 4.9 6.0 Loose to Medium Dense Medium Dense Black silty SAND with gravel, fine to medium sand, fine to coarse gravel, moist, moderate organic inclusions. (TOPSOIL) (SM) Brown GRAVEL with sand, fine to coarse sand, fine to coarse gravel, moist, scattered cobbles, trace silt. (GP) Brown-gray GRAVEL with silt and sand, fine to coarse sand, fine to coarse gravel, moist, cobbles. (GP-GM) Brown SAND with gravel, fine to coarse sand, fien to caorse gravel, moist, trace silt. (SP) Test pit terminated at approximately 9 feet (prior to caving). Heavy caving observed from 4 to 9 feet. No groundwater seepage observed. Sample No.Depth (ft)PROJECT NAME:PROJ. NO:LOGGED BY: LOCATION: DATE LOGGED: APPROX. ELEV: DEPTH TO CAVING: FIGURE DEPTH TO GROUNDWATER: SURFACE CONDITIONS: Description Consistency/ Relative Density W (%)interpreted as being indicative of other locations at the site. NOTE: This subsurface information pertains only to this test pit location and should not be 0 1 2 3 4 5 6 7 8 9 10 A-13 T-8777 SLK Yelm, Washington Medium/Long Grass August 19, 2022 Railway Road Development LOG OF TEST PIT NO.TP-12 N/A N/A 4 to 8 feet 2.8 4.3 3.0 Loose to Medium Dense Black silty SAND with gravel, fine to medium sand, fine to coarse gravel, moist, moderate organic inclusions. (TOPSOIL) (SM) Dark brown to brown GRAVEL with sand, fine to coarse sand, fine to coarse gravel, moist, scattered cobbles. (GP) *Scattered boulders observed within upper 3 feet. Brown SAND with gravel, fine to coarse sand, fien to caorse gravel, moist, trace silt. (SP) Test pit terminated at approximately 8 feet (prior to caving). Heavy caving observed from 4 to 8 feet. No groundwater seepage observed. Sample No.Depth (ft)PROJECT NAME:PROJ. NO:LOGGED BY: LOCATION: DATE LOGGED: APPROX. ELEV: DEPTH TO CAVING: FIGURE DEPTH TO GROUNDWATER: SURFACE CONDITIONS: Description Consistency/ Relative Density W (%)interpreted as being indicative of other locations at the site. NOTE: This subsurface information pertains only to this test pit location and should not be 0 1 2 3 4 5 6 7 8 9 A-14 T-8777 SLK Yelm, Washington Medium/Long Grass August 19, 2022 Railway Road Development LOG OF TEST PIT NO.TP-13 N/A N/A 2 to 8 feet 3.9 4.7 4.8 Loose to Medium Dense Medium Dense Black silty SAND with gravel, fine to medium sand, fine to coarse gravel, moist, moderate organic inclusions. (TOPSOIL) (SM) Brown to gray GRAVEL with sand, fine to coarse sand, fine to coarse gravel, moist, scattered cobbles, trace silt. (GP) Test pit terminated at approximately 8 feet. Slight to moderate caving observed from 2 to 8 feet. No groundwater seepage observed. Sample No.Depth (ft)PROJECT NAME:PROJ. NO:LOGGED BY: LOCATION: DATE LOGGED: APPROX. ELEV: DEPTH TO CAVING: FIGURE DEPTH TO GROUNDWATER: SURFACE CONDITIONS: Description Consistency/ Relative Density W (%)interpreted as being indicative of other locations at the site. NOTE: This subsurface information pertains only to this test pit location and should not be 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 A-15 T-8777 SLK Yelm, Washington Medium/Long Grass August 19, 2022 Railway Road Development LOG OF TEST PIT NO.TP-14 N/A N/A 7 to 12 feet 3.0 8.7 5.5 Loose to Medium Dense Medium Dense Black silty SAND with gravel, fine to medium sand, fine to coarse gravel, moist, moderate organic inclusions. (TOPSOIL) (SM) Brown GRAVEL with sand, fine to coarse sand, fine to coarse gravel, moist to wet, scattered cobbles. (GP) Small-scale pilot infiltration test completed at approximately 7 feet. Test pit terminated at approximately 12 feet (after PIT completion). Slight to moderate caving observed from 7 to 12 feet. No groundwater seepage observed. Sample No.Depth (ft)PROJECT NAME:PROJ. NO:LOGGED BY: LOCATION: DATE LOGGED: APPROX. ELEV: DEPTH TO CAVING: FIGURE DEPTH TO GROUNDWATER: SURFACE CONDITIONS: Description Consistency/ Relative Density W (%)interpreted as being indicative of other locations at the site. NOTE: This subsurface information pertains only to this test pit location and should not be 0 1 2 3 4 5 6 7 8 9 10 A-16 T-8777 SLK Yelm, Washington Medium/Long Grass August 19, 2022 Railway Road Development LOG OF TEST PIT NO.TP-15 N/A N/A 4 to 8 feet 2.7 5.4 5.9 Loose to Medium Dense Medium Dense Black silty SAND with gravel, fine to medium sand, fine to coarse gravel, moist, moderate organic inclusions. (TOPSOIL) (SM) Brown GRAVEL with sand, fine to coarse sand, fine to coarse gravel, moist, scattered cobbles. (GP) *Scattered boulders observed within upper 7 feet. Brown GRAVEL with silt and sand, fine to coarse sand, fine to coarse gravel, moist, scattered cobbles. (GP-GM) Test pit terminated at approximately 8.5 feet. Moderate caving observed from 4 to 8 feet. No groundwater seepage observed. Figure No. Project:Project No: Driller:Client: Relative DensitySoil Description Blows / foot 10 30 MoistureConsistency/ Content (%) Observ. Well Location:Depth to Groundwater: 50 SPT (N) Logged By: Approx. Elev: Date Drilled:Depth (ft)Sample Intervalpertains only to this boring location and should not be interpeted as being indicative of NOTE: This borehole log has been prepared for geotechnical purposes. This information other areas of the site 0 5 10 15 A-17LOG OF BORING NO. B-1 Railway Road Development T-8777 AEC, LLCBlue Fern Development, LLC 18 ft, 23 ftYelm, Washington MJX NA August 17, 2022 Very Dense Medium Dense Very Dense Dense Very Dense (3-inches organic TOPSOIL) Brown silty GRAVEL with sand, fine sand, fine to coarse gravel, dry, scattered cobbles, trace rootlets. (GM) Gray GRAVEL with silt and sand, fine sand, fine to coarse gravel, dry, numerous cobbles. (GP-GM) Brown GRAVEL with sand, fine to coarse sand, fine to coarse gravel, moist, scattered cobbles. (GP) Brownish-gray GRAVEL with silt and sand, fine to coarse sand, fine to coarse gravel, dry to wet, scattered cobbles. (GP-GM) *Continued on Next Page* 5.5 2.8 4.1 3.3 4.3 5.6 6.4 62/10" 28 50/6" 40 44 50/5" Figure No. Project:Project No: Driller:Client: Relative DensitySoil Description Blows / foot 10 30 MoistureConsistency/ Content (%) Observ. Well Location:Depth to Groundwater: 50 SPT (N) Logged By: Approx. Elev: Date Drilled:Depth (ft)Sample Intervalpertains only to this boring location and should not be interpeted as being indicative of NOTE: This borehole log has been prepared for geotechnical purposes. This information other areas of the site 20 25 30 35 A-17LOG OF BORING NO. B-1 Railway Road Development T-8777 AEC, LLCBlue Fern Development, LLC 18 ft, 23 ftYelm, Washington MJX NA August 17, 2022 Dense Medium Dense Gray GRAVEL with silt and sand, fine to coarse sand, fine to coarse gravel, dry, scattered cobbles, occasional silty sand seam. (GP-GM) Brown SAND with gravel, fine to coarse sand, fine to coarse gravel, moist, scattered cobbles. (GP) Brown to brownish-gray GRAVEL with silt and sand, fine to coarse sand, fine to coarse gravel, moist to wet, scattered cobbles. (GP-GM) Test Boring terminated at approximately 26.5 feet. Perched groundwater seepage observed at approximately 18 feet. Groundwater seepage observed at approximately 23 feet. Boring converted to groundwater monitoring well with Well ID no. BPA-201. 9.1 5.8 5.0 5.3 41 29 Figure No. Project:Project No: Driller:Client: Relative DensitySoil Description Blows / foot 10 30 MoistureConsistency/ Content (%) Observ. Well Location:Depth to Groundwater: 50 SPT (N) Logged By: Approx. Elev: Date Drilled:Depth (ft)Sample Intervalpertains only to this boring location and should not be interpeted as being indicative of NOTE: This borehole log has been prepared for geotechnical purposes. This information other areas of the site 0 5 10 15 A-18LOG OF BORING NO. B-2 Railway Road Development T-8777 AEC, LLCBlue Fern Development, LLC 23 ftYelm, Washington MJX NA August 17, 2022 Medium Dense Very Dense Medium Dense Very Dense (4-inches organic TOPSOIL) Grayish-brown silty GRAVEL with sand, fine sand, fine to coarse gravel, dry, scattered cobbles, occasional rootlet. (GM) Brown SAND with gravel, fine to coarse sand, fine to coarse gravel, moist, trace cobbles. (SP) Brownish-gray GRAVEL with silt and sand, fine to coarse sand, fine to coarse gravel, moist, trace cobbles. (GP-GM) Gray silty SAND with gravel, fine sand, fine to coarse gravel, dry, trace cobbles. (SM) Brown GRAVEL with silt and sand, fine to coarse sand, fine to coarse gravel, moist, trace cobbles. (GP-GM) *Continued on Next Page* 4.0 5.7 3.7 4.0 4.2 7.9 5.3 24 28 29 50/2" 26 51 Figure No. Project:Project No: Driller:Client: Relative DensitySoil Description Blows / foot 10 30 MoistureConsistency/ Content (%) Observ. Well Location:Depth to Groundwater: 50 SPT (N) Logged By: Approx. Elev: Date Drilled:Depth (ft)Sample Intervalpertains only to this boring location and should not be interpeted as being indicative of NOTE: This borehole log has been prepared for geotechnical purposes. This information other areas of the site 20 25 30 35 A-18LOG OF BORING NO. B-2 Railway Road Development T-8777 AEC, LLCBlue Fern Development, LLC 23 ftYelm, Washington MJX NA August 17, 2022 Dense Medium Dense Brown GRAVEL with silt and sand, fine to coarse sand, fine to coarse gravel, moist, trace cobbles. (GP-GM) Gray silty GRAVEL with sand, fine to medium sand, fine to coarse gravel, dry, scattered cobbles. (GM) Brown GRAVEL with silt and sand, fine to coarse sand, fine to coarse gravel, moist to wet, trace cobbles. (GP- GM) Test Boring terminated at approximately 26.5 feet. Groundwater seepage observed at approximately 23 feet. Boring converted to groundwater monitoring well with Well ID no. BPA-202. 4.1 9.7 11.2 39 29 Figure No. Project:Project No: Driller:Client: Relative DensitySoil Description Blows / foot 10 30 MoistureConsistency/ Content (%) Observ. Well Location:Depth to Groundwater: 50 SPT (N) Logged By: Approx. Elev: Date Drilled:Depth (ft)Sample Intervalpertains only to this boring location and should not be interpeted as being indicative of NOTE: This borehole log has been prepared for geotechnical purposes. This information other areas of the site 0 5 10 15 A-19LOG OF BORING NO. B-3 Railway Road Development T-8777 AEC, LLCBlue Fern Development, LLC 23 ftYelm, Washington MJX NA August 18, 2022 Medium Dense Very Dense Medium Dense Dense Very Dense (3-inches organic TOPSOIL) Brownish-gray GRAVEL with silt and sand, fine sand, fine to coarse gravel, dry, scattered cobbles, occasional rootlet. (GP-GM) Brown SAND with gravel, fine to coarse sand, fine to coarse gravel, moist, trace cobbles. (SP) Gray silty GRAVEL with sand, fine to coarse sand, fine to coarse gravel, dry, scattered cobbles. (GM) Brown GRAVEL with sand, fine to coarse sand, fine to coarse gravel, moist, trace cobbles. (GP) *Continued on Next Page* 2.8 2.8 3.6 3.3 3.9 5.2 11 50/6" 24 44 50/1" 50/4" Figure No. Project:Project No: Driller:Client: Relative DensitySoil Description Blows / foot 10 30 MoistureConsistency/ Content (%) Observ. Well Location:Depth to Groundwater: 50 SPT (N) Logged By: Approx. Elev: Date Drilled:Depth (ft)Sample Intervalpertains only to this boring location and should not be interpeted as being indicative of NOTE: This borehole log has been prepared for geotechnical purposes. This information other areas of the site 20 25 30 35 A-19LOG OF BORING NO. B-3 Railway Road Development T-8777 AEC, LLCBlue Fern Development, LLC 23 ftYelm, Washington MJX NA August 18, 2022 Dense Medium Dense Brown GRAVEL with silt and sand, fine to coarse sand, fine to coarse gravel, moist to wet, scattered cobbles, occasional silty gravel layer, occasional cemented silty sand seam. (GP-GM) Test Boring terminated at approximately 26.5 feet. Groundwater seepage observed at approximately 23 feet. Boring converted to groundwater monitoring well with Well ID no. BPA-203. 7.1 4.7 6.6 37 28 Figure No. Project:Project No: Driller:Client: Relative DensitySoil Description Blows / foot 10 30 MoistureConsistency/ Content (%) Observ. Well Location:Depth to Groundwater: 50 SPT (N) Logged By: Approx. Elev: Date Drilled:Depth (ft)Sample Intervalpertains only to this boring location and should not be interpeted as being indicative of NOTE: This borehole log has been prepared for geotechnical purposes. This information other areas of the site 0 5 10 15 A-20LOG OF BORING NO. B-4 Railway Road Development T-8777 AEC, LLCBlue Fern Development, LLC 23.5 ftYelm, Washington MJX NA August 19, 2022 Very Dense Medium Dense Very Dense Dense Very Dense (3-inches organic TOPSOIL) Brown silty GRAVEL with sand, fine sand, fine to coarse gravel, dry, trace cobbles, occasional rootlet. (GM) Gray GRAVEL with silt and sand, fine to coarse sand, fine to coarse gravel, dry, scattered cobbles. (GP-GM) Brown GRAVEL with sand, fine to coarse sand, fine to coarse gravel, moist, trace cobbles. (GP) Brownish-gray GRAVEL with silt and sand, fine to coarse sand, fine to coarse gravel, moist, scattered cobbles, trace sand with silt and gravel seams. (GP- GM) *Continued on Next Page* 5.9 4.8 2.9 4.9 4.2 5.8 63/7" 25 50/4" 37 42 55 Figure No. Project:Project No: Driller:Client: Relative DensitySoil Description Blows / foot 10 30 MoistureConsistency/ Content (%) Observ. Well Location:Depth to Groundwater: 50 SPT (N) Logged By: Approx. Elev: Date Drilled:Depth (ft)Sample Intervalpertains only to this boring location and should not be interpeted as being indicative of NOTE: This borehole log has been prepared for geotechnical purposes. This information other areas of the site 20 25 30 35 A-20LOG OF BORING NO. B-4 Railway Road Development T-8777 AEC, LLCBlue Fern Development, LLC 23.5 ftYelm, Washington MJX NA August 19, 2022 Dense Brownish-gray GRAVEL with silt and sand, fine to coarse sand, fine to coarse gravel, moist to wet, scattered cobbles, trace gravel with sand layers. (GP- GM) Test Boring terminated at approximately 26.5 feet. Groundwater seepage observed at approximately 23.5 feet. Boring converted to groundwater monitoring well with Well ID no. BPA-204. 4.4 4.8 5.1 9.9 40 30 Figure No. Project:Project No: Driller:Client: Relative DensitySoil Description Blows / foot 10 30 MoistureConsistency/ Content (%) Observ. Well Location:Depth to Groundwater: 50 SPT (N) Logged By: Approx. Elev: Date Drilled:Depth (ft)Sample Intervalpertains only to this boring location and should not be interpeted as being indicative of NOTE: This borehole log has been prepared for geotechnical purposes. This information other areas of the site 0 5 10 15 A-21LOG OF BORING NO. B-5 Railway Road Development T-8777 AEC, LLCBlue Fern Development, LLC 23.5 ftYelm, Washington MJX NA August 19, 2022 Medium Dense Very Dense Dense Medium Dense Very Dense (3-inches organic TOPSOIL) Grayish-brown silty GRAVEL with sand, fine sand, fine to coarse gravel, dry, trace cobbles, trace rootlets. (GM) Gray GRAVEL with silt and sand, fine to coarse sand, fine to coarse gravel, dry, trace cobbles, occasional silty gravel with sand layer. (GP-GM) Brown GRAVEL with sand, fine to coarse sand, fine to coarse gravel, moist, scattered cobbles, occasional silty sand seam. (GP) Brownish-gray GRAVEL with silt and sand, fine to coarse sand, fine to coarse gravel, moist, trace cobbles. (GP-GM) *Continued on Next Page* 7.5 3.7 4.7 4.5 3.5 4.5 3.8 10 55 42 38 28 50/4" Figure No. Project:Project No: Driller:Client: Relative DensitySoil Description Blows / foot 10 30 MoistureConsistency/ Content (%) Observ. Well Location:Depth to Groundwater: 50 SPT (N) Logged By: Approx. Elev: Date Drilled:Depth (ft)Sample Intervalpertains only to this boring location and should not be interpeted as being indicative of NOTE: This borehole log has been prepared for geotechnical purposes. This information other areas of the site 20 25 30 35 A-21LOG OF BORING NO. B-5 Railway Road Development T-8777 AEC, LLCBlue Fern Development, LLC 23.5 ftYelm, Washington MJX NA August 19, 2022 Very Dense Dense Gray GRAVEL with silt and sand, fine to coarse sand, fine to coarse gravel, moist, trace cobbles. (GP-GM) Gray silty GRAVEL with sand, fine to medium sand, fine to coarse gravel, dry, occasional sand seam. (GM) Brown GRAVEL with sand, fine to coarse sand, fine to coarse gravel, moist to wet, trace cobbles, occasional silty gravel with sand layer. (GP) Brownish-gray GRAVEL with silt and sand, fine to coarse sand, fine to coarse gravel, wet, trace cobbles, occasional sand with gravel layer, occasional silty sand seam. (GP-GM) Test Boring terminated at approximately 26.5 feet. Groundwater seepage observed at approximately 23.5 feet. Boring converted to groundwater monitoring well with Well ID no. BPA-205. 3.5 4.7 6.9 50/5" 31 Tested By: KJ LL PL D85 D60 D50 D30 D15 D10 Cc Cu Material Description USCS AASHTO Project No. Client:Remarks: Project: Location: Test Pit TP-1 Depth: 2.5 ft Sample Number: 1 Location: Test Pit TP-3 Depth: 8.5 ft Sample Number: 3 Location: Test Pit TP-5 Depth: 7 ft Sample Number: 3 Terra Associates, Inc. Kirkland, WA Figure 56.4623 35.8566 30.4101 21.3282 13.6951 9.4115 1.35 3.81 17.2540 0.7891 0.6837 0.5276 0.4134 0.3580 0.99 2.20 21.9184 13.7903 11.6897 6.6722 0.7791 0.5308 6.08 25.98 GRAVEL with sand GP SAND with gravel SP GRAVEL with sand GP T-8777 Blue Fern Development, LLC A-22PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 75.1 17.9 1.6 3.8 1.3 0.3 0.0 14.9 3.2 6.4 59.2 13.6 2.7 0.0 21.2 52.5 8.2 11.0 5.2 1.96 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Particle Size Distribution Report Railway Road Development Tested on August 25, 2022 Tested on August 25, 2022 Tested on August 25, 2022 Tested By: KJ LL PL D85 D60 D50 D30 D15 D10 Cc Cu Material Description USCS AASHTO Project No. Client:Remarks: Project: Location: Test Pit TP-7 Depth: 9 ft Sample Number: 3 Location: Test Pit TP-9 Depth: 6 ft Sample Number: 2 Location: Test Pit TP-14 Depth: 7 ft Sample Number: 1 Terra Associates, Inc. Kirkland, WA Figure 37.1997 15.3415 11.8160 3.3667 0.5055 0.3830 1.93 40.05 40.5003 21.4645 16.4217 6.2597 0.8071 0.5760 3.17 37.27 43.7204 18.1229 13.3667 4.8358 0.7034 0.5345 2.41 33.91 GRAVEL with sand GP GRAVEL with sand GP GRAVEL with sand GP T-8777 Blue Fern Development, LLC A-23PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 32.0 34.7 7.2 14.3 10.2 1.6 0.0 44.7 28.1 7.4 14.2 4.5 1.1 0.0 38.4 31.8 8.0 15.2 4.6 2.06 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Particle Size Distribution Report Railway Road Development Tested on August 25, 2022 Tested on August 25, 2022 Tested on August 25, 2022 Tested By: KJ LL PL D85 D60 D50 D30 D15 D10 Cc Cu Material Description USCS AASHTO Project No.Client:Remarks: Project: Location: Test Pit TP-14 Depth: 12 ft Sample Number: 4 Location: Test Boring B-1 Depth: 10 ft Sample Number: 4 Location: Test Boring B-1 Depth: 18 ft Sample Number: 8 Terra Associates, Inc. Kirkland, WA Figure 27.0251 16.0041 13.0392 6.6642 1.2803 0.7036 3.94 22.74 17.9332 9.3707 6.8828 2.0000 0.5395 0.4341 0.98 21.59 28.0022 13.6393 8.4617 2.3214 0.3077 0.1367 2.89 99.75 GRAVEL with sand GRAVEL with sand GP GRAVEL with silt and sand GP-GM T-8777 Blue Fern Development, LLC A-24PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 31.3 42.3 9.0 13.5 2.7 1.2 0.0 13.1 46.0 10.9 20.4 6.9 2.7 0.0 30.8 31.0 9.0 11.1 10.0 8.16 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Particle Size Distribution Report Railway Road Development Tested on August 25, 2022 Tested on August 25, 2022 Tested on August 25, 2022 GP Tested By: KJ LL PL D85 D60 D50 D30 D15 D10 Cc Cu Material Description USCS AASHTO Project No.Client:Remarks: Project: Location: Test Boring B-2 Depth: 7.5 ft Sample Number: 3 Location: Test Boring B-2 Depth: 15 ft Sample Number: 6 Location: Test Boring B-3 Depth: 5 ft Sample Number: 2 Terra Associates, Inc. Kirkland, WA Figure 25.8314 6.2331 0.7397 0.4912 0.3498 0.2970 0.13 20.99 22.1290 6.9852 3.5971 0.5542 0.3110 0.2201 0.20 31.73 25.3802 12.9903 9.1482 0.9952 0.2176 SAND with gravel SP SAND with silt and gravel SP-SM GRAVEL with silt and sand GP-GM T-8777 Blue Fern Development, LLC A-25PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 24.7 17.2 2.9 32.3 20.3 2.6 0.0 18.9 27.1 9.6 22.0 16.0 6.4 0.0 25.8 32.4 8.0 13.6 8.9 11.36 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Particle Size Distribution Report Railway Road Development Tested on August 25, 2022 Tested on August 26, 2022 Tested on August 26, 2022 Tested By: KJ LL PL D85 D60 D50 D30 D15 D10 Cc Cu Material Description USCS AASHTO Project No. Client:Remarks: Project: Location: Test Boring B-3 Depth: 20 ft Sample Number: 8 Location: Test Boring B-4 Depth: 12.5 ft Sample Number: 5 Terra Associates, Inc. Kirkland, WA Figure 17.5416 10.5426 8.2791 2.5294 0.3856 0.2186 2.78 48.22 18.3998 10.0489 7.0304 2.0189 0.4634 0.2732 1.48 36.78 GRAVEL with silt and sand GP-GM GRAVEL with silt and sand GP-GM T-8777 Blue Fern Development, LLC A-26PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 11.8 51.3 8.0 12.6 9.1 7.2 0.0 13.8 43.0 13.3 16.0 7.6 6.36 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Particle Size Distribution Report Railway Road Development Tested on August 26, 2022 Tested on August 26, 2022 Tested By: KJ LL PL D85 D60 D50 D30 D15 D10 Cc Cu Material Description USCS AASHTO Project No.Client:Remarks: Project: Location: Test Boring B-4 Depth: 15 ft Sample Number: 6 Location: Test Boring B-5 Depth: 12.5 ft Sample Number: 5 Terra Associates, Inc. Kirkland, WA Figure 14.3934 6.2135 3.4180 0.6014 0.2233 12.4289 7.1955 5.8119 2.5659 0.5297 0.4206 2.18 17.11 SAND with silt and gravel to GRAVEL with silt and sand SP-SM/GP-GM GRAVEL with sand GP T-8777 Blue Fern Development, LLC A-27PERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 6.3 38.3 12.5 19.5 12.8 10.6 0.0 2.7 55.3 13.2 18.6 8.3 1.96 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Particle Size Distribution Report Railway Road Development Tested on August 26, 2022 Tested on August 26, 2022 Project No. T-8777 APPENDIX B INFILTRATION LETTER February 7, 2023 Project No. T-8777 Ms. Anna Drumheller Blue Fern Development, LLC 18300 Redmond Way, Suite 120 Redmond, Washington 98052 Subject: Infiltration Testing Railway Road Development 16314 and 16330 Railway Road Southeast Yelm, Washington Reference: Geotechnical Report, Railway Road Development, 16314 and 16330 Railway Road South, Yelm, Washington, Project No. T-8777, prepared by Terra Associates, Inc., dated September 12, 2022 Dear Ms. Drumheller: As requested, we have completed infiltration testing for the proposed infiltration facility located in the northwest portion of the project site. Our infiltration testing consisted of one small-scale Pilot Infiltration Test (PIT). The test was conducted in general conformation with the procedures outlined in Section V-5.4 (Determining the Design Infiltration Rate of the Native Soils) of the 2019 Department of Ecology Stormwater Manual for Western Washington. The approximate location is shown on attached Figure 1. The test results are summarized below: Test No. Approximate Test Depth (ft) Steady State Flow Rate (gpm) Measured Infiltration Rate (Isat initial) (in/hr) Correction Factor CFT1 Estimated Design Infiltration Rate (Isat design = Isat initial x CFT) (in/hr) PIT-1 -6 64.00 367.83 0.225 82.76 ft Feet based on available topography gpm Gallons per minute in/hr Inches per hour 1 2019 Department of Ecology Stormwater Manual for Western Washington 12220 113th Avenue NE, Ste. 130, Kirkland, Washington 98034 Phone (425) 821‐7777 • Fax (425) 821‐4334 2-7-2023 90 5 S0' 50 45 45� 45 45 45 50' 50 50 S0 50' 63' 53 mTPy,10 p h y, y`_ n y0. P-14. 0) y�_ 0 y�, %� TP -13 ,q y� ypRs �%0h� n�%0tis �%0tiy 0% ^lytics m 70 yv m y0tiv m 1�0 s m �0yy m y�tiy m tis %'9 90 Q m y 50' 50" 50' 45" 45" 45' 45" 45 1 50' 50 50' 1 S0' 54W TP— P• 90 < m I 34 GGE95 6 TRAI .` 898± 5F 9e 'Al Ebt� m ryo,� 50' 45' 45' 45" 1 45' 185' 3, %� 10, 31 M m B— TP -14 vp0'y� B-4 y0�� 00 v1 A m n m m 0y 0 a` p b• p• P` p 90 yy 9, U� �� 0 0 45� 45� 45' 45 45' 50 Q�V 7 YS �00� 0A p0 S M1 y — �1y' 110 90 90 (Q��'7ti F co, J 'i1 ye 1p y . n y` 47 y y�. `� y� I `- h yap' m �v m 10 yy'� m t � m I-11 I m X00 m Q a o qj y y 0 0 0 0 % 110 pA y� 50' 45' 45 45" 45 45" 0' n � I I .z AA A h 110 • — — — — _ — — 90 � Q Lu y Eh 4]Eb 91' S0" 45 45' 45" 45' 45" 45' 50' i0' 3 m 110" �` v ^� y� A h y` 1p y n y` W ' W �m�0 • � � � PD• I � Pry PO PO R0 PO amy PO bye I %0 I �p� 90 % 110" 90 y� - P1 50 45' 45' 45" 45' 45' 45' 50 my� yy M 0,� B-2 co Qp� %° P Is f7� % 110 90 F EiENi10N �,� 0,�` ye `� nye •� n^,y` n�D�y� '� nv1p� np �` 0 p0 ti m o AR p, m ape m �0oi m 0m 0m 0m 0y m % o yp 'm R• R• a• P` P` a` a` b` ,d n l��i`�1'w p EEF 90' J' 91' 50' 45' 45" 45' 45 45% 45' i 0> Al 4 U RAIL A GESS A 9e' I In 900± 5F n % 31 50' 50' 50' 45' 45' 45' 45TP- 50' 50 50 P5 50" dl 719501 T —3 y� a yR m �ry0y m �� 00w 0 0� m co 0v m n 05 p 1D 0v h m m A mw m ryj 0w ry 0 0 I Ary m m m m ell, m % m % m m 0 m 0 m 0 0 m 0 i i �� >Y�,t m A• %0 %- �/Y 0 0 I PIL 90 50 50 50 50' 45' 45 45" 4 45 50" 50' 5s 50_ 50' _ 61� / NOTE: LEGEND: THIS SITE PLAN IS SCHEMATIC. ALL LOCATIONS AND APPROXIMATE TEST PIT LOCATION DIMENSIONS ARE APPROXIMATE. IT IS INTENDED FOR APPROXIMATE BORING LOCATION REFERENCE ONLY AND SFOULD NOT BE USED FOR DESIGN OR CONSTRUCTION PURPOSES. REFERENCE:SITE PLAN PROVIDED BY CORE DESIGN 0 100 200 APPROXIMATE SCALE IN FEET Test Number: Project Name: Project Number: Test Date: Test Procedure:Small‐Scale PIT Hole Dimensions:3'x5'x6'D Hole Area:15 square feet Time Flow Rate Head Cum. Volume Use mean flow rate over final 30 minutes (minutes)(gpm)(feet)(gallons) of test as steady state infiltration rate 64 0.57 3935 64.00 gallons per minute 8.56 cubic feet per minute Infiltration rate=steady state flow divided by area of pit 0.57 6.84 Time Head (minutes) (feet) 0.00 0.57 0.92 0.1 Steady Flow Rate Test 410.67 inches per hour Falling Head Test 367.83 inches per hour Correction factors from the 2019 DOE Stromwater Manangement Manual for Western Washington F‐testing 0.5 Facility width = 82.5 feet. F‐geometry 0.5 Assumed depth to groundwater = 10 feet below ground surface. F‐plugging 0.9 Corrected Steady State Infiltration Rate 92.40 inches per hour Corrected Falling Head Infiltration Rate 82.76 feet per minute inches per minute Measured Infiltration Rate Correction Factors Pond PIT Railway Road Development T‐8777 1/3/2023 Falling Head Test Steady State Flow Test