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HomeMy WebLinkAboutStudies APPLICANT 5/19/2022Geotechnical Investigation and Seismic Hazard Study South Hills 3rd Level Reservoir Replacement Springfield, Oregon Prepared for: Springfield Utility Board Springfield, Oregon May 16, 2022 Foundation Engineering, Inc. di h Foundation Engineering, Inc. Professional Geotechnical Services Steven Wages, P.E. May 16, 2022 Springfield Utility Board 202 S 18th Street Springfield, Oregon 97477 South Hills 3rd Level Reservoir Replacement Project No.: 2211098 Geotechnical Investigation and Seismic Hazard Study Springfield, Oregon Dear Mr. Wages: We have completed the requested geotechnical investigation and seismic hazard study for the above -referenced project. Our report includes a description of our work, a discussion of the site conditions, a summary of laboratory testing, and a discussion of engineering analyses. Recommendations for site preparation and foundation design and construction are also provided. A seismic hazard study was also completed to identify potential geologic and seismic hazards and evaluate the effect those hazards may have on the proposed site. The study fulfills the requirements presented in the 2019 Oregon Structural Specialty Code (OSSC 2019) for site-specific seismic hazard reports for essential and hazardous facilities, and major and special -occupancy structures. The 2019 OSSC is based on the 2018 International Building Code and ASCE 7-16. Results of the study (provided in Appendix D) indicate there are no geologic or seismic hazards that require special design consideration or would preclude construction of the proposed reservoir. The study was completed by Brooke Running, R.G., C.E.G. There are numerous values in geotechnical investigations that are approximate including calculated parameters, measured lengths, soil layer depths, elevations, and strength measurements. For brevity, the symbol "±" is used throughout this report to represent the words approximate or approximately when discussing these values. It has been a pleasure assisting you with this phase of your project. Please do not hesitate to contact us if you have any questions or if you require further assistance. Sincerely, FOUNDATION ENGINEERING, INC. David L. Running, P.E., G.E. Senior Geotechnical Engineer PRO% ;SVS �4GINEEq oy` _( 6264]Pc r°'eORE00N.,Um O 2W 9 �v°ja 2V 9`zp t. R�N�` RENS 12-31-2022 820 NW Cornell Avenue • Corvallis, Oregon 97330 • 541-757-7645 7857 SW Cirrus Drive, Bloo 24 • Beaverton, Oregon 97008 • 503-643-1541 GEOTECHNICAL INVESTIGATION AND SEISMIC HAZARD STUDY SOUTH HILLS 3RD LEVEL RESERVOIR REPLACEMENT SPRINGFIELD, OREGON "7e101L(H:16111101,, The Springfield Utility Board (SUB) is planning to replace an existing reservoir located in the south hills of Springfield, east of S. 66" Place. The site location is shown on Figure 1 A (Appendix A). The existing site layout is shown on Figure 2A (Appendix A). The existing reservoir is a 98 -foot diameter, 1.5 MG, concrete tank designated as Reservoir No. 1. It is proposed to replace Reservoir No. 1 with two smaller, 67 -foot diameter, 0.58 MG, steel tanks designated as Reservoir No. 2 and Reservoir No. 3. The proposed layout for the new tanks is shown on Figure 3A (Appendix A). Reservoir No. 2 will be constructed first and put in service. Then, Reservoir No. 1 will be taken off-line and demolished and Reservoir No. 3 will be constructed in the existing Reservoir No. 1 footprint. Both new reservoirs will be welded steel tanks, with a finish floor elevation (FIFE) of EI. 961.50, a maximum operational water surface elevation of EI. 982.75, and an overflow elevation of EI. 983.75. SUB is the project owner, Murraysmith is the lead design consultant, and Peterson Structural Engineers (PSE) is the structural designer. SUB retained Foundation Engineering, Inc. to conduct a geotechnical investigation for the project. Foundation Engineering previously completed an investigation for a seismic evaluation of the existing Reservoir No. 1 in 2013. The investigation included drilling three exploratory borings at the site to evaluate the subsurface conditions. The findings of the investigation were presented in a memorandum dated November 19, 2013. Information from that previous investigation was used to supplement the current investigation. Geotechnical information included in the as -built plans for Reservoir No. 1 was also utilized. LOCAL GEOLOGY Detailed discussions of the local and regional geology, tectonic setting, local faulting, historical seismicity, seismic hazards, and design earthquakes are included in the Site-specific Seismic Hazard Study report (Appendix D). References cited in this section are found in Appendix D. An abbreviated discussion of the local geology is provided below. The reservoir site is located on bench on a north -facing slope at the southeast edge of Springfield where it transitions from the Willamette Valley to the western foothills of the Western Cascades. The Oregon Department of Geology and Mineral Industries (DOGAMI) SLIDO and HazVu web viewers indicate the area is mapped as landslide terrain. South Hills 3rd Level Reservoir Replacement Mat 18, 2022 Geotechnical Investigation and Seismic Hazard Study 1 Pro act N., 2211098 Springfield. Oregon Springfield Utility Board A mapped landslide extends across the site with the headscarp located ±800 to 1,200 feet to the south (uphill) and landslide debris extending up to ±3,500 feet to the north (downhill). A series of smaller scarps are mapped uphill and downhill of the reservoir site. DOGAMI estimates the landslide to be more than 150 years old. We completed a reconnaissance of the reservoir site including the slopes immediately uphill and downhill of the existing and proposed tanks. We did not observe any signs of recent or active slope instability. Local geologic mapping indicates the project site and immediate surrounding area is generally underlain by volcaniclastic rock (Yeats et al., 1996; Hladky and McCaslin, 2006; McClaughry et al., 2010). The subsurface conditions in our explorations are generally consistent with the geologic mapping. Colluvial soils were encountered in each of the explorations extending to depths of up to ±20 feet below the ground surface. Colluvium consists of material that has been transported downslope and deposited via erosion, creep, or landslide activity. Based on the terrain, we anticipate the colluvium was deposited during previous landslide activity. The colluvium is typically underlain by residual soil (i.e., bedrock that has decomposed in place to the consistency of soil) followed by tuff, siltstone, sandy siltstone, and silty sandstone. Details are provided in the Subsurface Conditions section below, cross-sections in Appendix A, and on the boring logs in Appendix B. FIELD EXPLORATION 2013 Investigation We drilled three exploratory borings (BH -1 through BH -3) at the site as part of our previous investigation on October 9, 2013. BH -2 and BH -3 were drilled adjacent to Reservoir No. 1 and BH -I was drilled uphill of the reservoir site on Jessica Drive to provide information to develop a subsurface cross-section. The borehole locations are shown on Figures 2A and 3A. Drilling was completed using a truck -mounted, CME 75 drill rig with mud -rotary drilling and HQ wire -line coring techniques. The borings extended to maximum depths ranging from ±30.8 to 35 feet. Disturbed samples were obtained in the borings in conjunction with the Standard Penetration Test (SPT) at 2.5 -foot intervals to ±15 feet, then at 5 -foot intervals thereafter. The SPT provides an indication of the density or stiffness of the soil. Continuous, HO -sized coring was completed in BH -1 from ± 15 to 35 feet, after competent bedrock was encountered. Upon completion of drilling, BH -1 and BH -2 were backfilled with bentonite chips in accordance with Oregon Water Resources Department (OWRD) guidelines. The bentonite backfill was capped with gravel and asphaltic concrete (AC) cold patch in BH -1, which was drilled on Jessica Drive and with gravel in 1311-3, which was drilled on the gravel access road adjacent to the tank. South Hills 3rd Level Reservoir Replacement Mat 16, 2022 Geotechnical Investigation and Seismic Hazard Study 2 Preset No.: 2211098 Springfield. Oregon Springfield utility Hoard A one -inch inside diameter (I.D.) standpipe piezometer was installed in BH -2 to allow measurement of groundwater levels. The standpipe extends to a depth of ±25 feet and is slotted from ± 15 to 25 feet. The installation was capped at the ground surface with a Morris monument set in concrete. After installation, the boring was bailed to remove the drilling fluid, then allowed to recharge over a period of several days before measuring. The explorations were continuously logged during drilling. The final logs (Appendix B) were prepared based on a review of the field logs, the laboratory test results, and an examination of the soil and bedrock samples in our office. Photos of the rock core from BH -1 are also provided in Appendix B. 2021 Investigation We drilled two exploratory borings (BH -4 and BH -5) adjacent to the proposed Reservoir No. 2 location on October 27, 2021. The borehole locations are shown on Figures 2A and 3A. Drilling was completed using a track -mounted, CME 55 tracked drill rig with mud -rotary drilling techniques. BH -4 extended to a depth of ±26.5 feet and BH -5 extended to a depth of ±30.4 feet. Both borings terminated in bedrock. Disturbed SPT samples were obtained in the borings at 2.5 -foot intervals to ±20 feet, then at 5 -foot intervals thereafter. Upon completion of drilling, the boreholes were backfilled with bentonite chips in accordance with OWRD guidelines. The bentonite backfill was capped with soil cuttings in BH -4, which was drilled in an undeveloped area, and with gravel in BH -5, which was drilled on the edge of the gravel access road. The explorations were continuously logged during drilling. The final logs (Appendix B) were prepared based on a review of the field logs, laboratory test results, and an examination of the soil and bedrock samples in our office. Previous Explorations by Others SUB provided as -built plans (latest revision dated August 1982) for the existing Tank 1 prepared by CH2M Hill, Inc. The plans indicate CH2M Hill dug exploratory test pits as part of their investigation for the tank. The test pits extended to depths ranging from ±5 to 12 feet and were dug prior to the site grading for the current facility. Selected sheets are provided in Appendix B including Sheet 1 (Vicinity Map, Site Layout, Index to Drawings) which shows the test pit locations and Sheet 2 (Test Pit Logs, Reservoir Excavation, Roadway Section) which shows the test pit logs. The locations of the test pits nearest to existing and proposed reservoirs are also shown on Figures 2A and 3A. Information from the test pits was used to help characterize the site conditions. South Hills 3rd Level Reservoir Replacement Mat 18, 2022 Geotechnical Investigation and Seismic Hazard Study 3 project No.: 2211098 Springfield, Oregon Springfield Utility Board The topographic contours shown on Figures 2A and 3A are based on the current North American Vertical Datum of 1988 (NAVD88). Topographic contours shown on plan Sheet 1 are based on the older National Geodetic Vertical Datum of 1929 (NGVD29). The ground surface elevations on Sheet 1 may be adjusted to NAVD88 by adding 3.55 feet to the NGVD29 contours. LABORATORY TESTING The laboratory testing included moisture content and Atterberg Limits tests to help classify the soils according to the Unified Soil Classification System (USCS) and estimate their overall engineering properties. Non -tested samples were visually classified in accordance with ASTM D 2487 and ASTM D 2488. USCS symbols shown on the boring logs for untested samples should be considered approximations. The test results are summarized in Table 1C (Appendix C). The moisture contents are also shown on the boring logs (Appendix B). The Atterberg limits tests indicate the colluvium and residual soil that underlie the site have high plasticity with liquid limits ILLI ranging from 67 to 85, plasticity indices (PI) ranging from 31 to 37, and a USCS classification of MH. SUMMARY OF SITE CONDITIONS Surface Conditions The existing Reservoir No. 1 (and proposed Reservoir No. 3 location) occupies a cut bench. There is a gravel access road that extends along the perimeter of the existing tank. Surface elevations on the bench range from ±EI. 968 on the south (uphill) side to ±EI. 960 on the north (downhill) side. Photos 1A through 3A (Appendix A) show the current site conditions. The proposed Reservoir No. 2 site slopes gently down to the north. Surface elevations within the proposed tank footprint range from ±EI. 968 on the south (uphill) side to ±El. 961 on the north (downhill) side. The ground surface in this area is densely vegetated with grass, weeds, ferns, blackberries, and scattered trees. Photos 4A and 5A (Appendix A) show the current conditions. South Hills 3rd Level Reservoir Replacement Mat 16, 2022 Geotechnical Investigation and Seismic Hazard Study 4 Pro ect No.: 2211098 Springfield, Oregon Springfield Utility Board Subsurface Conditions The borings encountered subsurface profiles that typically include the following strata: • Fill. Fill was encountered in the borings adjacent to Reservoir No. 1 extending to depths of ±8 feet in BH -2 and ±7 feet in BH -3. The fill was used to backfill around the lower portion of the tank and to grade the terrain for the access road. The fill is variable and includes stiff gravelly clay and soft to medium stiff clay with some sand, and soft to medium stiff clay and silty clay or clayey silt with trace gravel and scattered cobbles and boulders. The fill is similar in consistency to the underlying colluvium and was likely generated from onsite excavations during the construction of Reservoir No. 1. Fill is also exposed at the ground surface across the eastern portion of the proposed Reservoir No. 2 location east of BH -4. The surficial fill at this location consists of silt and clay with gravel to boulder -sized basaltic rock fragments. Based on the as -built plans, it appears this fill represents material that was excavated from the Reservoir No. 1 footprint and stockpiled at this location. Surficial fill was also encountered in BH -1 and BH -5. The fill in BH -1 was limited to the pavement section (i.e., AC and base rock) on Jessica Drive and the fill in BH -5 was limited to ±9 inches of silty gravel used to construct the access road. • Colluvium. Colluvium (i.e., landslide deposits) was encountered in BH -1 beneath the Jessica Drive pavement, extending to ±7 feet. Adjacent to Reservoir No. 1, the colluvium was encountered beneath the fill, from ±8 to 30 feet in BH -2 and from ±7 to 20 feet in BH -3. At Reservoir No. 3, the colluvium extended to ±13.8 feet in BH -4 and ±5 feet in BH -5 - The colluvium is variable, but primarily consists of stiff to very stiff sandy clay, sandy silt, or clayey silt with trace to some sand and gravel. Scattered cobble to boulder -sized rock fragments were observed in the colluvium in BH -2. The variable nature of the material is typical of colluvial soil. • Residual Soil. Residual soil (i.e., bedrock decomposed to the consistency of soil) was encountered beneath the colluvium all borings except BH -2. The residual soil was observed from ±7 to 10 feet in BH -1, from ±20 to 25 feet in BH -3, from ± 13.8 to 18.8 feet in BH -4, and from ±5 to 20 feet in BH -5. Residual soil may also be present above the bedrock in BH -2, but it was not encountered within the selected sampling intervals. The residual soil includes very stiff to hard sandy clay or clayey silt with some sand. Relict sandstone texture was observed in samples of the residual soil in BH -4 and BH -5. South Hills Sid Level Reservoir Replacement Mat 15, 2022 Geotechnical Investigation and Seismic Hazard Study 5 Proiect No.: 2211096 Springfield, Oregon Springfield Utility Hoard Bedrock. Bedrock was encountered in each of the borings at ± 10 feet in BH -1 , at ±30 feet in BH -2, at ±25 feet in BH -3, at ± 18.8 feet in BH -4, and at ±20 feet in BH -5. The bedrock includes tuff, siltstone, sandy siltstone, and silty sandstone. The bedrock is decomposed to slightly weathered at the surface and generally becomes less weathered with depth. The rock hardness ranges from extremely weak (RO) to very weak (R1). The rock typically becomes less weathered and harder with depth. The siltstone core from BH -1 from ±25 to 35 feet indicates the rock has very close to moderately close, planar to irregular, rough, open joints. Rock Quality Designation (ROD) values in the rock core ranged from ±82 to 90 percent consistent with good quality. The test pit logs provided in the as -built drawings by CH2M Hill typically describe silty clay with basalt boulders or basalt boulders in a silty clay or silty sand matrix. From the description and depths indicated in the logs, we expect these soils correspond with the colluvium encountered in the recent borings. TP -4 indicated weathered siltstone from ±4 to 12 feet. No further description of the siltstone was provided. Based on its depth, this material may be consistent with the material we are classifying as residual soil. We developed three cross-sections across the site utilizing topographic data and the subsurface information from the borings. The cross-section locations are shown on Figures 2A and 3A. The cross-sections are shown on Figures 4A through 6A (Appendix A). Groundwater Mud -rotary drilling precluded an accurate measurement of the groundwater in the borings at the time of drilling. The piezometer in BH -2 was used to evaluate the groundwater levels at the site. Groundwater measurements taken on October 16 and November 7, 2013, and on October 27, 2021, are summarized in Table 1. Table 1. Groundwater Depths and Elevations (BH -2) Date Groundwater Depth (ft) Groundwater Elevation (ft) 11/16/13 23.2 944.5 11/7/13 16.0 951.7 10/27/21 16.4 951.3 The lower groundwater reading (±23.2 feet) was taken during a period of relatively dry weather, while the higher groundwater readings (±16 feet and 16.4 feet) were taken after several days of moderate rain. The available data suggests a significant rise in the water table can occur in response to moderate rainfall. South Hills 3rd Level Reservoir Replacement Mat 16, 2022 Geotechnical Investigation and Seismic Hazard Study 6 Project No.: 2211098 Springfield, Oregon Springfield Utility Board DISCUSSION Reservoir No. 2 Reservoir No. 2 will be a welded steel tank with a diameter of 67 feet, a FFE of EI. 961.50, a maximum operational water surface elevation of EI. 982.75, and an overflow elevation of EI. 983.75. The tank will have a 1/,inch thick steel floor plate and a perimeter ring footing. No interior column footings will be required. A minimum of 2 feet of compacted crushed rock will be placed beneath the floor and a minimum of 1 foot of compacted crushed rock will be placed beneath the perimeter footing. The current ground surface elevations within the planned footprint of the tank and perimeter access road range from ±EI. 961 to ±EI. 970. Site grading for Reservoir No. 2 will require excavations extending up to ± 10 feet below the current site grades to allow for construction of the perimeter access road and a granular building pad supporting the tank. Based on the available information, we anticipate the excavations will encounter surficial fill followed by colluvium or residual soil. The fill will likely consist of a mixture of fine-grained soil and sand to boulder -sized rock fragments. The required excavations will remove the fill and terminate in colluvium or residual soil comprised of predominantly clayey silt with some sand. SPT N -values recorded in the colluvium and residual soil correlate to medium stiff to very stiff consistency, however, these N -values were recorded in soil having moisture contents above 40%. Fine-grained soils with high moisture contents are typically sensitive to disturbance and develop pore water pressure when penetrated by a split -spoon sampler, resulting in low SPT N -values. Therefore, we anticipate the SPT N -values underestimate the soil strength and the colluvium and residual soil are generally stiff to very stiff. Reservoir No. 3 Reservoir No. 3 be a welded steel tank with the same general configuration as Reservoir No. 2 including a FFE of EI. 961 .50, a maximum operational water surface elevation of El, 982.75, and an overflow elevation of EI. 983.75. Reservoir No. 3 will have a Y inch thick steel floor plate and a perimeter ring footing. No interior column footings will be required. Reservoir No. 3 will be located within the existing Reservoir No. i footprint. Reservoir No. 1 has a 98 -foot diameter and a FFE of 956.75. Reservoir No. 1 will be partly demolished with the removal of the roof, interior support columns, and the portion of the perimeter wall that extends above -grade. The buried portion of the perimeter wall and the floor slab will remain in place. The as -built plans for Reservoir No. 1 indicate the existing floor slab is typically 6 inches thick, transitioning to a 16 -inch thick by 4 -foot wide perimeter footing. The plans also indicate the floor slab and perimeter footing are underlain by at least 1 foot of compacted granular fill. South Hills 3rd Level Reservoir Replacement Mat 16, 2022 Geotechnical Investigation and Seismic Hazard Study 7 Project No., 2211096 Springfield. Oregon Springfield Utility Board Holes will be made in the existing floor slab to allow for drainage and compacted crushed rock will be placed over the floor slab to grade the terrain beneath the new tank. The crushed rock between the new tank floor will be up to 4.25 feet thick. Cut Slopes No retaining walls are currently planned. The site grading will require a permanent cut slope on the south side of Reservoir No. 2. Based on the terrain and the soil conditions, we recommend grading permanent cut slopes at 2(H):1 (V) or flatter. The site should he graded to drain surface water away from the tanks. All cut and fill slopes should be seeded as soon as practical to allow time to establish vegetation before the wet winter and spring months. Temporary cut slopes for the project should be made in accordance with OR OSHA standards. We anticipate the colluvium and residual soil will correspond to an OR-OSHA Class B soil due to its stiffness and plasticity. OR-OSHA recommends a maximum temporary cut slope of 1(H):1(V) in Class B soil. The soil may degrade when exposed to rainfall. Therefore, suitable cut slopes in these soils will have to be confirmed in the field at the time of construction. Construction Timing The colluvium and residual soil are predominantly fine-grained and will be moisture-sensitive. These materials will be susceptible to softening and erosion when wet. Therefore, we recommend completing the earthwork in dry summer months (typically mid-June through the end of September). Completing the earthwork during this period will also allow time to establish vegetation on the cut slopes before the wet season. ENGINEERING ANALYSIS Seismic Design A detailed seismic hazard study was completed for the site and the findings are summarized in Appendix D. The study concluded there are no seismic hazards that would preclude construction of the proposed reservoirs, provided the earthwork is completed as recommended herein. Site Response Spectra. We developed site response spectra for the site in accordance with AWWA D1OO-11 Section 13.2.7. The AWWA D1OO-11 site response is separated into components with an impulsive component representing the structure with 5% damping and a convective component with 0.5% damping representing the fluid contents. Based on the interpreted cross-sections, we anticipate the new tanks will be underlain by stiff to very stiff colluvium and residual soil followed by relatively shallow bedrock. We have concluded the subsurface conditions correspond most closely to an AWWA Site Class C. South Hills 3rd Level Reservoir Replacement Mat 16, 2022 Geotechnical Investigation and Seismic Hazard Study 8 Project No., 2211098 Springfield, Oregon Springfield Utility Board AWWA D100-11 references ASCE 7-05 for seismic design. Seismic design in ASCE 7-05 utilizes USGS 2002 seismic maps. For our evaluation of the tank site, we used the updated USGS 2014 maps referenced in ASCE 7-16 and OSSC 2019 to provide the spectral accelerations consistent with the current building codes. Risk -targeted maximum considered earthquake (MCER) spectral accelerations on bedrock were obtained using modified USGS 2014 maps with 2% probability of exceedance in 50 years (i.e., a ±2,475 -year return period). The modifications include factors to adjust the spectral accelerations to account for directivity and risk. We also used the USGS 2014 maps to determine maximum considered earthquake (MCE) spectral accelerations on bedrock for a 10% probability of exceedance in 50 years (i.e., a ±475 -year return period), in case it is needed for design. The bedrock spectral accelerations were multiplied Fe and Fv values selected from ASCE 7-16 Tables 11-4-1 and 11-4-2 to calculate spectral accelerations at the ground surface. The AWWA D100-11 site response spectra for 2% probability of exceedance in 50 years are shown on Figure 7A (Appendix A). The site response spectra for 10% probability of exceedance in 50 years are shown on Figure 8A (Appendix A). Vertical Accelerations. Design vertical acceleration (Av) may be calculated as 0.14Sos based on AWWA D100-11 Section 13.5.4.3, using Sus from Figure 7A. Liquefaction. Liquefiable soils typically consist of saturated, loose sands and non -plastic or low plasticity silt (i.e., a PI of less than 8). Our borings indicate the site is underlain by predominantly stiff to very stiff soil with medium to high plasticity. These soils are not susceptible to liquefaction. Therefore, there is no liquefaction hazard at the site. Slope Stability Analysis. Because the site is located within mapped landslide topography, we completed slope stability analysis to address potential instability concerns. The analyses were completed for Cross -Sections A -A' and C -C' shown on Figures 4A and 6A. We did not complete analysis for Cross -Section B -B' because that cross-section is not aligned with the direction of movement of the original landslide. Also, the subsurface conditions on Cross -Section B -B' are similar to the other cross-sections. Both static and seismic conditions were analyzed. Strength parameters for the soil units were estimated from available correlations based on SPT N -values, laboratory tests, and visual classifications. Typical strength tests (e.g., direct shear or triaxial shear) were not practical based on the variable nature of the colluvium and residual soil. Strength parameters were assigned to the colluvium, residual soil, and bedrock, as well as an assumed thin soil layer at the interface between the colluvium and residual soil. South Hills 3rd Level Reservoir Replacement Mat 18, 2022 Geotechnical Investigation and Seismic Hazard Study 9 Project No.: 2211098 Springfield, Oregon Springfield Utility Board Reduced strength parameters were assumed for this interface layer because previous movement is expected to have occurred along this interface. Strength parameters were not assigned to the surficial fill because this material is limited in extent. The strength parameters vary slightly for static and seismic conditions. For static analysis, the soil strength was modeled using internal friction angles (�) and no cohesion (c) assuming drained loading conditions. For seismic analysis, an apparent cohesion was added for the colluvium and residual soil to account for the soil response to dynamic loading. Groundwater conditions for the analysis were based, in part, on the groundwater measurements from the piezometer in BH -2 and an estimation of the upper -bound and average groundwater levels. We assumed the phreatic surface would approximately follow the estimated slope of the bedrock surface. For static loading conditions, we assumed the phreatic surface would correspond to a depth of ±10 feet at BH -2. We anticipate this groundwater level represents an upper -bound condition. For seismic loading, we assumed the phreatic surface would correspond to a depth of ±15 feet at BH -2. We anticipate this depth will represent an average groundwater condition during the winter and spring. Seismic conditions were simulated using pseudo -static analysis. For pseudo -static analysis, a design horizontal acceleration (kh) of one-third to one-half of the estimated peak ground surface acceleration (Aa) is typically used. The reduction accounts for the non -rigid nature of the soil and the fact the peak ground acceleration only exists for a short period of time and does not necessarily align perpendicular to the slope (Kramer, 1996). For the analysis, we assumed a kh value of 0.1 Big corresponding to 0.5As. Aa was calculated by multiplying the estimated peak bedrock acceleration for a 2% in 50 -year return interval (0.308) by a site amplification factor (FPGA) of 1.2, assuming a Site Class C soil classification. The program SL/DE 5.0 was used to complete the two-dimensional stability analysis utilizing Bishop, Janbu, and Spencer methods. Circular and block failure modes were analyzed. The circular failure search was limited to areas where a slope failure could impact the reservoirs. The block failure search focused on the zone extending beneath the reservoirs and assumed a failure surface approximately following the interface between the colluvium and residual soil (i.e., along the failure surface of the previous landslide). For Reservoir No. 2, a nominal uniform pressure of 1,500 lbs/foot2 (psf) was applied on the ground surface within the tank footprint to represent the dead load imparted by the water and the structure. For Reservoir No. 3, a nominal uniform pressure of 2,000 psf was applied on the ground surface within the tank footprint to represent the dead load imparted by the water, the structure, and the crushed rock used to backfill beneath the structure. South Hills 3rd Level Reservoir Replacement Mat 16, 2022 Geotechnical Investigation and Seismic Hazard Study 10 Project Nri 2211098 Springfield, Oregon Springfield Utility Board The output from the analyses is presented in Appendix E. A factor of safety (FS) of at least 1.5 is typically required for static conditions where slope stability can affect a critical facility. A FS of at least 1 .1 is typically required for seismic conditions. For all cases, the results indicate FS values greater than 1 .5 for critical failure surfaces that would impact the new tanks. The relatively high FS values are due to the stiffness of the colluvium and residual soil, the relatively shallow bedrock depth, and the relatively level bedrock surface. Bearing Capacity For Reservoir No. 2, we calculated an ultimate bearing capacity for the ring footing assuming the footing will bear on 1 foot of compacted crushed rock underlain by foundation soil with a 0 of 28 degrees and c of 200 psf. The calculations indicate an ultimate bearing capacity of 9,000 psf. This value corresponds to an allowable bearing pressure of 3,000 psf with a typical factor of safety of 3. A one-third increase in the allowable bearing pressure (i.e., 4,000 psf) may be used in evaluating short-term seismic loads. The allowable bearing pressures provided above may also be used for the design of Reservoir No. 3. We anticipate the allowable bearing pressures will be conservative for Reservoir No. 3 because the ring footing for that structure will be underlain by a thicker section of granular fill and the Reservoir No. 1 floor slab, which will help spread the foundation load. Settlement Reservoir No. 3. The maximum operational water level in Reservoir No. 3 will approximately match the operational water surface elevation in the original tank (Reservoir No. 1). The net increase in bearing pressure beneath the new tank is estimated to bet205 psf due to the weight of the steel floor and the thickened granular fill section under the floor. The existing Reservoir No. 1 floor slab that will remain in place beneath the new tank will also help distribute the load. For these conditions, we anticipate the total foundation settlement will be less than % inch and the differential settlement between the center and edges of the new tank floor will be Y. inch or less. Reservoir No. 2. The net increase in vertical stress for Reservoir No. 3 will be higher. We calculated a net increase of ±885 psf beneath the center of the floor to account for the removal of an average of 6 feet of existing fill and colluvium and the addition of 2 feet of crushed rock, a A -inch thick steel floor plate, and 21.25 feet of water. We assumed the perimeter ring footing will be 2.5 feet wide with a dead load in the range of 1,500 to 2,000 psf. We completed settlement analysis for Reservoir No. 3 using the computer program Settle3D. We assigned a range of compressibility parameters for the colluvium and residual soil based on our previous experience with similar stiff to very stiff soil. The underlying bedrock was assigned a low compressibility. South Hills 3rd Level Reservoir Replacement Mat 16, 2022 Geotechnical Investigation and Seismic Haeard Study 11 Pmjei No.: 2211098 Springfield, Oregon Springfield Utility Board Our analysis indicates the total settlement may be up to ± 1 inch with up to ± % inch of differential settlement between the center and edges of the tank. The calculations indicate most of the settlement is due to the weight of the water rather than the weight of the structure. Therefore, most of the settlement is expected to occur during or shortly following the initial filling of the tank. Some long-term, post-construction settlement (i.e., creep) should also be expected. Staging the initial filling of the tank may be used to help the structure adjust to the total and differential settlement. If this approach is selected, we recommend initially filling the tank only halfway and monitoring settlements for a period of at least 2 weeks. If the rate and magnitude of settlement are confirmed to be close to or below the estimated values and the pattern of settlement is relatively uniform, the tank may be filled relatively quickly. Otherwise, we recommend filling the tank in stages while monitoring the settlement. Sliding Coefficient and Passive Resistance for Footings The footings and tank floors will bear on compacted crushed rock. For sliding analysis, we recommend using a coefficient of friction of 0.5 between the base of the concrete and the crushed rock. Passive resistance of the backfill in front of the buried footings was calculated as an equivalent fluid density equal to y'Kp, where y is the unit weight of the backfill and Kip is the passive earth pressure coefficient. We anticipate the footings for Reservoir No. 2 will be backfilled with compacted crushed rock surrounded by medium stiff colluvium or residual soil. For these conditions, we calculated the passive pressure on the footings assuming an average y of 120 pcf (lbs./ft) and an average � of 34 degrees. The calculations indicate the ultimate passive resistance may be modeled using an equivalent fluid density of ±420 pcf. We anticipate the ring footing for Reservoir No. 3 will be backfilled with compacted crushed rock extending at least 10 feet beyond the edges of the tank. For these conditions, we calculated the passive pressure on the footings assuming a y of 130 pcf and a 0 of 38 degrees. The calculations indicate the ultimate passive resistance may be modeled using an equivalent fluid density of ±550 pcf. The passive resistance may be combined with the sliding resistance at the base of the footings to evaluate the overall lateral resistance, however, the sliding and ultimate passive resistances will develop with different displacements. The sliding resistance will develop with very small transitional movement. Development of the ultimate passive resistance on the footings may require a lateral displacement corresponding to 1 % of the buried footing height. South Hills 3rd Level Reservoir Replacement Mat 16, 2022 Gecnechnical Investigation and Seismic Hazard Study 12 Protect No.: 2211098 Springfield. Oregon Springfield Utility Board DESIGN AND CONSTRUCTION RECOMMENDATIONS Design and construction recommendations are provided in the following sections. We recommend contractors be provided a copy of this report to review the site conditions and recommendations for site preparation and foundation construction. The construction recommendations provided below assume earthwork will occur during dry weather. These recommendations will need to be modified if the work is completed during wet weather. General Earthwork 1. Select Fill as defined in this report should consist of % or 1 -inch minus, clean (i.e., less than 5% passing the #200 U.S. Sieve), well -graded, angular crushed rock. We should be provided a gradation sheet for this material for approval prior to delivery to the site. 2. Drain Rock should consist of % to 11/,inch, clean (less than 2% passing the #200 sieve), open -graded, angular, crushed quarry rock. Other gradations may be acceptable, provided the rock is durable and free draining. We should be provided a gradation sheet for this material for approval prior to delivery to the site. 3. Separation Geotextile should be a non -woven or non -woven geotextile with Mean Average Roll Value (MARV) strength properties meeting the requirements of an AASHTO M 288-17 Class 2 Separation Geotextile with a maximum AOS of 0.6 mm (max average roll value) and a permittivity greater than 0.05 sec'. We should be provided a specification sheet on the selected geotextile for approval prior to delivery to the site. 4. Subsurface Drainage Geotextile should be a non -woven geotextile with Mean Average Roll Value (MARV) strength properties meeting the requirements of an AASHTO M 288-17 Class 3 Subsurface Drainage Geotextile, with a maximum AOS of 0.22 mm (max average roll value) and a permittivity greater than 0.1 sec'. We should be provided a specification sheet on the selected geotextile for approval prior to delivery to the site. 5. Compact all fill in loose lifts not exceeding 12 inches. The lift thickness should be reduced to 6 inches where light or hand -operated equipment is used. Compact all fill to a minimum of 95% relative compaction. The maximum dry density of ASTM D 698 should be used as the standard for estimating relative compaction. The moisture content of the fill should be adjusted to within ±2% of its optimum value prior to compaction. Field density tests should be run frequently to confirm adequate compaction of the fill. South Hills 3rd Level Reservoir Replacement Mat 16, 2022 Geotechnical Investigation and Seismic Hazard Study 13 Project No.: 2211098 Springfield, Oregon Springfield Utility Board Foundation Design and Construction 6. Design the tanks using the seismic design parameters and response spectra shown on Figures 7A and 8A. 7. Design the footings using an allowable bearing pressure of 3,000 psf. This value may be increased by one-third for transient loads. The allowable bearing pressure assumes the footings will bear on at least 1 foot of compacted Select Fill underlain by stiff soil. S. For Reservoir No. 2, assume the total foundation settlement will be less than 1 inch and the differential settlement will be %4 inch or less. 9. For Reservoir No. 3, assume the total foundation settlement will be less than Y� inch and the differential settlement will be % inch or less. 10. Use a coefficient of sliding friction of 0.5 between the bottom of the footings and the compacted Select Fill and a coefficient of sliding friction of 0.4 between the bottom of the steel floors and the compacted Select Fill. The ultimate passive resistance for the buried ring footing at Reservoir No. 2 may be calculated using an equivalent fluid density of 420 pcf. The ultimate passive resistance for the buried ring footing at Reservoir No. 3 may be calculated using an equivalent fluid density of 550 pcf. Assume sliding friction will develop with very little movement, but a lateral displacement of up to 1 % of the buried footing height will be required to mobilize the ultimate passive resistance. Foundation Preparation Reservoir No. 2 11. Strip the existing ground as required to remove roots and organics. The typical stripping depth is expected to be ±4 inches. Deeper stripping and grubbing depths will be required where trees are encountered. Dispose of all strippings outside of construction areas. 12. Excavate the tank area as required to provide a minimum of 2 feet of Select Fill beneath the floor and 1 foot of Select Fill beneath the ring footing. The excavation of the ring footing would extend at least 1 foot beyond the edges of the footing. We recommend completing the final excavation using an excavator equipped with a smooth-edged bucket to reduce subgrade disturbance. All loose or disturbed soil should be removed prior to backfilling. 13. Use Select Fill to backfill the tank excavation. Place and compact the fill in lifts as recommended in Item 5. South Hills 3rd Level Reservoir Replacement Mat 16, 2022 Geotechnical Investigation and Seismic Hazard Study 14 Project No.: 2211098 Springfield, Oregon Springfield Utility Board 14. Grade the area surrounding the tank to promote runoff away from the foundation. Surface runoff should be collected by swales or a French drain and directed away from the tank. Concentrated runoff should not be directed onto native slopes. Reservoir No. 3 15. Demolish the roof, interior columns, and above -grade walls of the existing tank. Existing interior columns should be cut off at least 2 feet below the bottom of the new floor. Drill or punch several holes in the existing floor slab to allow for drainage. Haul all construction debris off site. 16. Use Select Fill to backfill inside the existing reservoir footprint as required to grade for the new ring footing and floor. Place and compact the fill in lifts as recommended in Item 5. 17. Grade the area surrounding the tank to promote runoff away from the foundation. Surface runoff should be collected by sweles or a French drain and directed away from the tank. Concentrated runoff should not be directed onto native slopes. Access Road Reservoii No. 2 18. Excavate the access road subgrade to accommodate a minimum of 12 inches of Select Fill. Compact the subgrade surface to mitigate any surface disturbance. Proof -roll the subgrade using a loaded, 10 -yd' dump truck or other heavy construction vehicle approved by Foundation Engineering prior to placing the Select Fill. Soft or pumping subgrade identified during the proof -roll may be moisture -conditioned and recompacted, or overexcavated and replaced with compacted Select Fill and proof -rolled again. 19. We recommend providing a Separation Geotextile beneath the Select Fill to reduce the risk of subgrade intrusion into the base rock. The Separation Geotextile should be laid flat over the subgrade and pulled tight to remove wrinkles. A minimum of ±2 feet of overlap should be provided between adjacent rolls of the Separation Geotextile. The geotextile should be overlapped in the direction the fill will be placed to reduce the risk of separation. Place a minimum of 12 inches of Select Fill over the Separation Geotextile to construct the base rock section. Compact the Select Fill as recommended in Item 5. South Hills 3rd Level Reservoir Replacement Mat 16, 2022 Geotechnical Investigation and Seismic Hazard Study 15 Project No.: 2211098 Springfield Oregon Springfield Utility Board Reservoir No. 3 20. The perimeter access road for Reservoir No. 3 will be located within the footprint of Reservoir No. 1. We recommend backfilling the Reservoir No. 1 footprint using Select Fill placed and compacted as recommended in Item 5. A Separation Geotextile is not required at this location. Cut and Fill Slopes 21. Temporary cut slopes should be excavated or shored in accordance with OR OSHA recommendations. 22. We anticipate the medium stiff to stiff colluvium and residual soil will correspond to an OR OSHA Type B soil. OSHA recommends excavating temporary cut slopes no steeper than 1 (H):1 (V) in Type B soil. The soil may degrade when exposed to rainfall. Therefore, the appropriate soil type and suitable temporary cut slopes will have to be confirmed in the field at the time of construction. 23. The permanent cut slope on the south side of the tanks should be graded at 2(H):1(V) or flatter. Fill slopes should also be graded no steeper than 2(H):I M. 24. Soil that is left exposed on slopes will also be susceptible to raveling and erosion. Therefore, following construction, all exposed ground surfaces should he vegetated as soon as practical so that a mature vegetation cover is in place prior to the onset of wet weather. Residual soil exposed in the cut slopes may be relatively sterile for growing vegetation. Therefore, it may be necessary to dress the finished surfaces with topsoil or use an appropriate fertilizer and erosion control blanket to help establish vegetation. We assume specific recommendations of the type of vegetation will be provided by others. Drainage A perimeter foundation drain is not required around the tanks if the site is adequately graded to direct surface water away from the foundations. However, a perimeter drain may be desirable for leak detection, if so, the system should be built as described below. These recommendations may also be used for constructing a French drain to intercept surface runoff. 25. The foundation drain, if needed, should consist of a 6 -inch diameter, perforated HDPE or PVC pipe. The flowline of the pipe should be set at least 12 inches below the bottom of the floor. The pipe should be bedded in at least 4 inches of Drain Rock and backfilled to within 6 inches of the ground surface with Drain Rock. The mass of Drain Rock should be wrapped in a Subsurface Drainage Geotextile that laps at least 12 inches at the top. South Hills Srd Level Reservoir Replacement Mat 16, 2022 Gap achurical Investigation and Seismic Hazard Study 16 Project No.: 2211098 Springfield, Oregon Springfield Utility Board 26. Provide clean -outs at appropriate locations for future maintenance of the drainage system. 27. Discharge the water from the drain system away from the tank in a manner that will not cause local erosion or ponding at the outlet of the drainpipe. DESIGN REVIEW/CONSTRUCTION OBSERVATION/TESTING We should be provided the opportunity to review all drawings and specifications that pertain to site preparation and foundation construction. Site preparation will require field confirmation of the subgrade conditions beneath the tanks. That confirmation should be done by a Foundation Engineering representative. Mitigation of any subgrade pumping will also require engineering review and judgment. Frequent field density tests should be run on all engineered fill. VARIATION OF SUBSURFACE CONDITIONS, USE OF THIS REPORT, AND WARRANTY The analysis, conclusions, and recommendations contained herein assume the subsurface profiles observed in the borings and test pits are representative of the site conditions. The above recommendations assume we will have the opportunity to review final drawings and be present during construction to confirm the assumed soil and groundwater conditions in the excavations. No changes in the enclosed recommendations should be made without our approval. We will assume no responsibility or liability for any engineering judgment, inspection, or testing performed by others. This report was prepared for the exclusive use of the Springfield Utility Board and their design consultants for the South Hills 3rd Level Reservoir Replacement project in Springfield, Oregon. Information contained herein should not be used for other sites or for unanticipated construction without our written consent. This report is intended for planning and design purposes as described herein. Contractors using this information to estimate construction quantities or costs do so at their own risk. Our services do not include any survey or assessment of potential surface contamination or contamination of the soil or groundwater by hazardous or toxic materials. We assume those services, if needed, have been completed by others. Our work was done in accordance with generally accepted soil and foundation engineering practices. No other warranty, expressed or implied, is made. South Hills 3rd Level Reservoir Replacement Geotechnical Investigation and Seismic Hazard Study Springfield, Oregon REFERENCES AASHTO, 2017, Geosynthetic Specification for Highway Applications, American Association of State Highway Transportation Officials (AASHTO), M288-17, June 2017. ASCE, 2017, ASCE 7-16: Minimum Design Loads and Associated Criteria for Buildings and Other Structures, American Society of Civil Engineers (ASCE), ISBN 978-0-7844-7996-4. ASTM, 2011, Standard Test Method for Classification of Soils for Engineering Purposes (Unified Soil Classification System, USCS): American Society of Testing and Materials (ASTM) International, ASTM Standard D2487, DO]: 10.1520/D2487-11, 11 p. ASTM, 2009, Standard Test Method for Description and Identification of Soils (Visual -Manual Procedure): American Society of Testing and Materials (ASTM) International, ASTM Standard D2488, DOI: 10.1520/D2488 -09A, 11 p. AWWA, 2011, Welded Carbon Steel Tanks for Water Storage, Q1004 1): American Water Works Association (AWWA), July 1, 2011. DOGAMI, 2020, SLIDO (Statewide Landslide Information Database for Oregon) Viewer, SLIDO-4.2: Oregon Department of Geology and Mineral Industries (DOGAMI), website: http://www.oregongeology.com/sub/slido/index.htm, updated October 30, 2020, accessed November 2021. IBC, 2018, International Building Code: International Code Council, Inc., Sections 1613 and 1803.3. Kramer, S.L., 1996, Geotechnical Earthquake Engineering, Published by Prentice Hall OSSC, 2019, Oregon Structural Speciality Code (OSSC): Based on the International Code Council, Inc., 2018 International Building Code (IBC), Sections 1613 and 1803. OR -OSHA, 2011, Oregon Administrative Rules, Chapter 437, Division 3 - Construction, Subdivision P - Excavations: Oregon Occupational Safety and Health Division (OR -OSHA), 1926.650, www.osha.orlpdf/rules/division3/div3.pdf. South Hills 3rd Level Reservoir Replacement Mat 1 Geotechnical Investigation and Seismic Hazard Study 18 Pro ect No.:: Springfield, Oregon Springfield Utili di hk Appendix A Figures and Site Photos Foundation Engineering, Inc. Professional Geotechnical Services h c a� SITE \ \ L I SCALE IN FEET NOTE: BASE MAP OBTAINED FROM THE USGS WEBSITE (https://ngmdb.usgs.gov). 0 1000 2000 4000 Foundation Engineering Inc. VICINITY MAP FIGURE NO. Professional Geotechnical Services PROJECT NO. DATE DRAWN BY SOUTH HILLS 3RD LEVEL RESERVOIR REPLACEMENT 1A 22nass ocr zozi MLM SPRINGFIELD, OREGON ID' PUE .A' — APPROX LOC A)3AND 12' W _ --4� _ _ _ �i OF EXIST W H _�- c i -`. – — -- v SBH 311��I�- 13 �+.... Lz- PROPOSE[? SII EXISTING TP 7 FSE IVO_2\ 3RD LEVEL RES NO. 1 IN P-5 98' DIA 1'u sD �.I 1� t��1 _ it" 1.5MG • r EXIST PARTIALLY BURIED, PRE -STRESSED CONC RES Le -W g.. Q �BH1'T BH 1 - Foundation Engineering 9� `\������ `�� ��� ��. ' �. �\� �\` �\ `\ ` y _ wGTP4-CH2MHill Test Plt L �L LIIL L ����� L! g` �� A A Cross -Section Location �:d` vIT,tA��,. �f V �-' SCALE IN FEET 0 2D 40 80 NOTES: IIIII ���I EXISTING SITE LAYOUT AND EXPLORATIONS FIGURE NO. 1. EXPLORATION LOCATIONS WERE ESTABLISHED REFERENCING EXISTING LANDMARKS AND ARE APPROXIMATE. JIVUII IUW4 Foundation Engineering, Inc. 2. SEE REPORT FOR A DISCUSSION OF SUBSURFACE CONDITIONS. Professional Geotechnical Services 3. BASE MAP WAS PROVIDED BY MURRAYSMITH. PROJECT No. DATE: DRAWN BY: SOUTH HILLS 3RD LEVEL RESERVOIR REPLACEMENT 2A 4. CROSS-SECTIONS A -A' AND C -C' EXTEND NORTH OFF OF THE PAGE. SEE FIGURE 3A FOR NORTHERN EXTENTS. 22tto9s Mar ts, zazz MLM SPRINGFIELD, OREGON LEGEND BH -1 - Foundation Engineering Boring 9 TP -4 - CH2M Hill Test Pit A -A' - Cross -Section Location NOTES: 1. EXPLORATION LOCATIONS WERE ESTABLISHED REFERENCING EXISTING LANDMARKS AND ARE APPROXIMATE. 2. SEE REPORT FOR A DISCUSSION OF SUBSURFACE CONDITIONS. 3. BASE MAP WAS PROVIDED BY MURRAYSMITH. 4. CROSS-SECTIONS A -A' AND C -C' EXTEND SOUTH OFF OF THE PAGE. SEE FIGURE 2A FOR SOUTHERN EXTENTS. BH -1 SCALE IN FEET 0 20 40 80 A Ar PROPOSED RES. 3 )090 995 EXISTING RES. 1 j 990 \ 985 980 C WO O965 PS-1.987 O / sort Lr M11 0staa ff coulnaraane organics BH-3 rEL Ment) J say CIHY to xE N GUY wit basalt etudes _ _ Q sa l91LT('11) x LOl 990 Sort 9raeelly ur-cy wme sa 4 II n N ¢EL 9•A'i W Slasalt bouli In / 955 SO'C come TP-0 aE a", ne pry xE1. 955 5 snMalail W 959 (xE1. 948 C) Vary Alfl to Lard clayey SILT. a / Stili to very skfl sandy OlAY, some Minn. tram b some 945 xE1. 0440 �Ity CLAY ace allays clur 9rtyeadend, MtWlea 5'Jty C".5sedo eronepiiile_ x11. 953.0 — - (w odium) and derltle¢ II 949 xEl. 94oi ? red SILTETONE Very ¢YR Canby CLAY (residual soli) e_e_ _ _ _xEl. olT 935 a _. _i saeT — - ' xEl. M3e� EMremely waak gas) SILTSTONE 930 d"r o Ekmmnly waak (RC) TUFF xE1. 92A2 925 920 SCALE IN FEET 0 15' 30' 60' NOTES: 1. CROSS-SECTION A-A' BASED ON SURVEY BY MURRAYSMITH. IOW ��pp����,, CROSS-SECTION A-A' �L FOUriCI&ilOri Engineering, Inc. FIGURE NO. 2. SEE FIGURES 2A AND 3A FOR LOCATION OF CROSS-SECTION A-A'. aiiiiii Protes9i0i Ob016C119I191 Services 3. SEE REPORT FOR A DISCUSSION OF SUBSURFACE CONDITIONS. PROJECT NO. DATES DRAWN eY'. SOUTH HILLS 3RD LEVEL RESERVOIR REPLACEMENT �� 4. SYMBOL-? - DENOTES THE ASSUMED SOIL1BEDROCK CONDITIONS BETWEEN EXPLORATION LOCATIONS. 2211098 mAY 18, zozz yi SPRINGFIELD, OREGON C C' SCALE IN FEET 0 15' 30' 60' NOTES: 1. CROSS-SECTION C -C' BASED ON SURVEY BY MURRAYSMITH, 2. SEE FIGURES 2A AND 3A FOR LOCATION OF CROSS-SECTION C -C'. 3. SEE REPORT FOR A DISCUSSION OF SUBSURFACE CONDITIONS. 4. SYMBOL -? - DENOTES THE ASSUMED SOILIBEDROCK CONDITIONS BETWEEN EXPLORATION LOCATIONS. PROPOSED RES 2 BH Jessica Drive 1000 -t (ke1. 892.61 995 / s4N xnrm do", SILT.ew aevel(mllovium) 990 s, 9r 966 � � kE1. 8BE.fi VerysllN deysy 61LT(resitlusl soul EI 882.6 980 6Mmmel L9>].6. Vweek (PO)TV FF 975 S(remely weeF Wvery week / (ROb Rt)sently 81LT8TONE Z 970 BH5 I' -EB 686.q O 965 (e EL 9620) Nedsms.r (osrMday°y Q 969 SILT, soma sanE (c°IluvLum� / Mo01am adb Taomn W 9S5 s(Fdayay511 nd(colluvium) EEL 95]0 LEI. 956.0 Medicmarip(° srifldayey SILT, some sa ntl antl gravel Very 6411 assay SILT. some sand Iluvium) �sns IL v - SEL 9520 — kE1. 9522 950 a — Vary .. darO daySl L'. Very alMro hard d, SILT, some sand(reaidual mil) 9M soma 66ndlre6moel6�1) _ fEL 90]2 �t FaVemelyweakb wryweak(RONRI) a— J sE1. 9424 sandy SILTSTONE 940 - Looser lV weak (P OJ ellf/9PN O9TONE kE1. 847.9 9g9P 935 Vary weak Rt) saley SIL lS 101.E 930 aELsalm 925 920 SCALE IN FEET 0 15' 30' 60' NOTES: 1. CROSS-SECTION C -C' BASED ON SURVEY BY MURRAYSMITH, 2. SEE FIGURES 2A AND 3A FOR LOCATION OF CROSS-SECTION C -C'. 3. SEE REPORT FOR A DISCUSSION OF SUBSURFACE CONDITIONS. 4. SYMBOL -? - DENOTES THE ASSUMED SOILIBEDROCK CONDITIONS BETWEEN EXPLORATION LOCATIONS. M 0.8 0.7 N 0.6 c O � 0.5 a � 0.4 1j 0.3 N ON 0.1 a t r r -I T 1- AWWA Response Spectrum Convective Components - I r AMA Response Spectrum _ Impulsve Components 2 4 6 8 10 12 Period (seconds) Notes: 1. The Design Response Spectra are based on the General Procedure in AW WA D100-11 Section 13.2. 7 with a 2% probability of exceedenee in 50 years. 2. The following parameters were used for the impulsive component response spectrum: Site Class= C Damping = 5% Ss= 0.63 Fe= 1.25 Srns= 0.78 Sas— 0.52 S, = 0.36 F,= 1.50 Su, = 0.54 Sm = 0.36 3. Sc and S, values indicated in Note 2 are USES 2014 risk -targeted MCE spectral accelerations available from Ifflua utaismicmaps.oM. 4. F, and F„ rere selected from ASCE 7-16 Tables 11.4-1 and 11.4-2 based on the Ss and Si values. Sus and Sm values include a 213 reduction on Sues and Sun as discussed in AWWA D100-11 Section 13.2.7. 5. The response spectrum for the convective components was calculated based on AW WA Di 00-11 Eq. 13-12. 6. Site location is: Latitude 44.0347, Longitude -122.9097. FIGURE 7A AWWA D100-11 SITE RESPONSE SPECTRA 2% Probability of Exceedence in 50 years South Hills 3rd Level Reservoir Replacement Springfield, Oregon Project No.: 2211098 0.6 0.5 3 0.1 0.0 mse Spectrum Components AVrWA Response Spectrum Impuleve Components 0 2 4 6 8 10 12 Period (seconds) Notes: 1. The Design Response Spectra are based on the General Procedure in AV VA D100-11 Section 13.2.7 with a 10% probability of exreedence in 50 years. 2. The follovdng parameters were used for the impulsive component response spectmm Site Class = C Damping = 5% Se = 0.26 F, = 1.30 S.- 0.33 St= 0.13 F„= 1.50 Sx,= 0.20 3. Ss and S, values indicated in Nate 2 are USGS 2014 MCE spectral accelerations corrected for directivity available from httpslf:seismicmaps.org. 4. F, and F, were selected from ASCE 7-16 Tables 11.4-1 and 11.4-2 based on the Ss and S, values. 5. The response spectrum for the convective eemponents was calculated based on AVMA D100-11 Eq. 13-12. 6. Site location is: Latitude 44.0347; Longitude -122.9097. FIGURE 8A AWWA D100-11 SITE RESPONSE SPECTRA 10% Probability of Exceedence in 50 years South Hills 3rd Level Reservoir Replacement Springfield, Oregon Project No.: 2211098 Foundation Engineering, Inc. South Hills 3rd Level Reservoir Replacement Project No.: 2201098 Photo 1A. Existing surface conditions south of Reservoir No. 1 looking east. Photo 2A. Existing surface conditions west of Reservoir No. 1 looking northeast. Foundation Engineering, Inc. South Hills 3rd Level Reservoir Replacement Project No.: 2201098 Photo 3A. Existing surface conditions north of Reservoir No. 1 looking east. Photo 4A. Existing surface conditions at the proposed Reservoir No. 2 location looking southeast. Foundation Engineering, Inc. South Hills 3rd Level Reservoir Replacement Project No.: 2201098 Photo 5A. Existing surface conditions at the proposed Reservoir No. 2 location looking southwest. Ah Professional Geotechnical Services Appendix B As -Built Plans, Boring Logs, and Rock Core Photos Foundation Engineering, Inc. DISTINCTION BETWEEN FIELD LOGS AND FINAL LOGS A field log is prepared for each exploration by our field representative. The log contains information concerning sampling depths and the presence of various materials such as gravel, cobbles, and fill, and observations of groundwater. It also contains our interpretation of the soil conditions between samples. The final logs presented in this report represent our interpretation of the contents of the field logs and the results of the sample examinations and laboratory test results. Our recommendations are based on the contents of the final logs and the information contained therein and not on the field logs. VARIATION IN SOILS BETWEEN EXPLORATIONS The final log and related information depict subsurface conditions only at the specific location and on the date indicated. Those using the information contained herein should be aware that soil conditions at other locations or on other dates may differ. Actual foundation or subgrade conditions should be confirmed by Foundation Engineering during construction. TRANSITION BETWEEN SOIL OR ROCK TYPES The lines designating the interface between soil, fill or rock on the final logs and on subsurface profiles presented in the report are determined by interpolation and are therefore approximate. The transition between the materials may be abrupt or gradual. Only at boring or test pit locations should profiles be considered as reasonably accurate and then only to the degree implied by the notes thereon. SAMPLE AND TEST SYMBOLS SS -3-4 C - Pavement Core Sample Sample Number CS - Rock Core Sample Exploration Number OS -Oversize Sample (3 -inch O.D. split -spoon) Sample Type S - Grab Sample SH - Thin-walled Undisturbed Sample Top of Sample Attempt SS - SPT Sample (2 -inch O.D. split -spoon) Recovered Portion • Standard Penetration Test resistance equals the number Unrecovered Portion of blows a 140 lb. weight falling 30 in. is required to drive a standard split -spoon sampler 1 ft. Practical refusal is SH SS Bottom of Sample Attempt equal to 50 or more blows per 6 in. of sampler penetration. • Water Content (%) FIELD SHEAR STRENGTH TEST GROUNDWATER Shear strength measurements on test pit side walls, Groundwater Location blocks of soil or undisturbed samples are typically — made with Towers or Field Vane shear devices. (1/3121) Date of Measurement Values reported as undrained shear strength (S,) in tsf. TYPICAL SOIL/ROCK SYMBOLS ® Concrete ® Silt Basalt ® Organics Sand Sandstone ® Clay Gravel Siltstone SII h Foundation Engineering, Inc. Professional Geotechnical Set -vices UNIFIED SOIL CLASSIFICATION SYMBOLS G - Gravel W - Well Graded S - Sand P - Poorly Graded M - Silt L - Low Plasticity C - Clay H - High Plasticity Pt - Peat O - Organic EXPLORATION LOG KEY IMPORTANT INFORMATION AND SYMBOLS Explanation of Common Terms Used in Soil Descriptions Field Identification Cohesive Soils Granular Soils SPT- Sr** (tsf) Term SPT" Term Easily penetrated several inches by fist. 0-2 x0.125 Very Soft 0-4 Very Loose Easily penetrated several inches bythumb. 2-4 0.125-0.25 Soft 4-10 Loose Can be penetrated several inches by thumb with moderate effort. 4-3 0.25-0.50 Medium Stiff 10-30 Medium Dense Readily indented by thumb but penetrated only with ffo grantert. 8-15 0.50-1.0 Stiff 30-50 Dense Readily indented by thumbnail. 15-30 1.0-2.0 Very Stiff >50 Very Dense Indented with difficulty by thumbnail. > 30 > 2.0 Hard ' SPT N -value in blows per foot (bpr) ' Untrained shear strength Term Soil Moisture Field Description Dry Absence of moisture. Dusty. Dry to the touch. Damp Soil has moisture. Cohesive soils are below plastic limit and usually moldable. Moist Grains appear darkened. but no visible water. Silt/clay will clump. Sand will bulk. Soils are often at or near plastic Can be rolled into a thread with some difficulty. limit. 15-30 Visible water on larger grain surfaces. Sand and mhesionless silt exhibit dilatancy. Cohesive sail can be readily Wet remolded. Soil leaves wetness on the hand when squeezed. Soil is wetter than the optimum moisture content and Easily rolled and re -rolled into thread. above the plastic limit. Term PI Plasticity Field Test Nan -plastic 0-3 Cannot be rolled into a thread at any moisture. Lew Plasticity 3- 15 Can be rolled into a thread with some difficulty. Medium Plasticity 15-30 Easily rolled into thread. High Plasticity > 30 Easily rolled and re -rolled into thread. Term Soil Structure Criteria Stratified Alternating layers at least''/. inch thick. Laminated Alternating layers less than 'A inch thick. Fissured Contains shears and partings along planes of weakness. Slickensided Palings appear glossy or striated. Blecky Breaks along surfaces into smaller lumps or blocks. Slickensides may be visible. Lensed Contains pockets of different soils. Term Soil Cementation Criteria Weak Breaks under light finger pressure. Moderate Breaks under hard finger pressure. Strong Wit not break with finger pressure. Foundation Engineering, Inc.I EXPLORATION LOG KEY Professional Geotechnical Services COMMON SOIL DESCRIPTION TERMS Explanation of Common Terms Used in Rock Descriptions Field Identification Weathering Field Identification UCS (psi) Strength Hardness Rock mass is generally fresh. Discontinuities are stained and may contain clay. Some discoloration in rock fabric. Mcderatedly Significant portions of rock show discoloration and weathering effects. Crystals are dull and show visible chemical Weathered (ODOT) Indented by thumbnail. R0 '100 Extremely Weak Extremely Soft Crumbles under firm blows with geological hammer. Decomposed Rock mass is completely decomposed. Original rock' fabric' maybe evident (relict texture). Maybe reduced ideal l Wide with hand pressure. Can be peeled by a packet knife. R1 100- 1,000 Very Weak Very Soft Can be peeled by a pocket knife with difficulty, shallow indentations made by firm blow with geological hammer. R2 1,000-4,000 Weak Soft Cannot be scraped or peeled with a pocket knife, specimen can be fractured with a single blow of geological hammer. R3 4,000-8,000 Medium Strang Medium Hard Specimen requires more than one blow of geological hammer to R4 8,000-16,000 Strong Hand fracture it. Specimen requires many blows ofgeological hammer to fracture it. R5 1 116,000 1 Very Strong Very Hard Term (ODOT) Weathering Field Identification Fresh Crystals are bright. Discontinuities may show some minor surface staining. No discoloration in rock fabric. Slightly Weathered Rock mass is generally fresh. Discontinuities are stained and may contain clay. Some discoloration in rock fabric. Mcderatedly Significant portions of rock show discoloration and weathering effects. Crystals are dull and show visible chemical Weathered alteration. Discontinuities are stained and may contain secondary mineral deposits. Highly Weathered Rock can be excavated with geologist's pick. All discontinuities exhibit secondary mineralization. Complete (Predominately discoloration of rack fabric. Surface of core is friable and usually pitted due to washing out of highly altered minerals Decomposed) by drilling water. Decomposed Rock mass is completely decomposed. Original rock' fabric' maybe evident (relict texture). Maybe reduced ideal l Wide with hand pressure. Spacing (metric) Spacing (imperial) Spacing Term Bedding/Foliation <6 cm <2 in Very Close Very Thin (Laminated) 6cm-30 cm 2in-1ft Close Thin 30 cm -90 can lit-3ft Moderately Close Medium 90 cm-3.Om 311-101 Wide Thick > 3.0 in > 10 it Very Wide Very Thick (Massive) Vesicle Term Volume Some vesicles 5-25% Highly vesicular 25-50% Scoriaceous > 50% Stratification Term Description Lamination < 1 can(0.4 in) thick beds Fissile Preferred break along laminations Parm, Prepared break parallel to bedding Foliation Metamorpic layering and segregation of minerals RQD % Designation RQD % Designation 0-25 Very Poor 75-90 Good 11 25-50 Poor g0-100 Excellent 50-75 Fair Rock Quality Designation (RQD) is the cumulative length of intact rock core pieces 4 inches or longer (excluding breaks caused by drilling and handling) divided by run length, expressed as a percentage. AWWII Foundation Engineering, Inc. I EXPLORATION LOG KEY Professional Geotechnical Services COMMON ROCK DESCRIPTION TERMS Depth Soil and Rock Description May. ♦ SPT, 0 Moisture, % Baokgg/ and Log Samples N -Value InstallationsI Feat comments Depth Rewvery ® RQD., % Water Table 992.63 992.9 0 50 1a0 %ASPHALTIC CONCRETE (+5 incM1es). 993.2 Capped with 1 1 Dense CRUSHED GRAVEL, (xT'ncbes); grey, damp, I .. 951 a AC cold 2 Bi-inch_minus (base rock). t0 - patch and _ _J CLAY to sandy gravel; brown, Son - ♦ • gravel 3 andsanin ained,SILT,trace iron and manganese -stained, damp to moist, metlium SS1-1 tt Barldilled 4 to coarse sang fine, subangulargravel, to (colluvium).ne (colluvium), bentonite 5 SS1-2 �f chips 6 7, ____________ 985.6 Very stiff clayey SILT; lighlgrey, iron and 7,6 L e manganesestained, damp, medium plasticity, SS1-3 24 (residual soil). 9 10 _____ ________________ Exbemelyweak(RD) TUFF; light grey antl 9926 100 SS1-0 �.... - 14, 11 iron -stained, decomposed.12 3 Y 13 6S1-5 66. 14 15 __ _ ____ _ ___ - 9]]6 • Extremely weak(RO)sandy SILT3TONE; greyto 150 SS -16 48 16 brown, ironslained. decomposed, fine to coarse sand. _ 1] _ 18 _- 19 20 Blu"my and highly to moderately weathered below — SS1a 5 21 ±20 feet. —_ - 22 _ 23 _- 24 = 25 Very weak (RI), slightly weathered to fresh, very dose 8S1 -e ;301 3, 26 to moderately dose, planar to irregular, and open — csvl joints below ±25 feet. 27 28 29 _ 30 CS -1-2 31 32 _ 33 —_ 34 —_ 35 — 957,6 BOTTOM OF BORING 35.0 Project No.. 21 31 02 8-1 01 Boring Log: 131-1-1 Surface Elevation: 992.6 feet (Approx.) Springfield Utility Board (SUB) Date of Boring October 9, 2013 South Hills Reservoir A h Foundation Engineering, jne. Springfield, Oregon MW Page 1 of 1 Depth Soil and Rock Description Elev. • SPT, @ Molsture,% Backfill/ and Log Samples N-Value Installadorer Feer Comments Depth Recovery ® RQD.,% Water Table 05000 Soft t0 medium stiff silty CLAY to clayey SILT, some 90 Morris 1 and, trace to some gravel, scattered cobbles and monument boulders; brown to red-brown, iron and set in 2 manganese-stained, moist, medium plasticity, fine to concrete 3 coarse, subangularmavel, (fill). 562-1 6 Bentonite 4 chips s s2 s 1-inch I.D. 7 PVC 8 — — --_— --___ 9597 562-3 Very stiff t0 hard clayey SILT,me sand, trace to sa e 0 9 some gravel, scattered cobbles and boulders; brown to grey, iron and manganese-stained, moist, medium 10 to high plasticity, fine to coarse sand, fine to coarse, 5624 '� 'g 11 subangular gravel,(colluNum). t18-inch diameter boulder encountered from x11 to 12 12.5 feet. 13 SSF2 5 1 14 Col 15-IF silicaa sand 6z� fig: "� 16 Ground 17 water level 19 0.010 20 5627 ,3 41 -: machine slat 21 screen 22 23 24 Ground water level 26 y I. (10-i6-13) sze 46 :._ 28 - ..... .... 27 Bentonite 28 chips 29 30 ________________ 9377 Extremely weak (ROJ SILTSTCTIN blueyrey, slightly 30.0 562-9 ! ifi weathered. 93s: 30.8 BOTTOM OF BORING Project No.. 2131028-101 Boring Log: BH-2 Surface Elevation: 967.7 feet (Approx.) Springfield Utility Board (SUB) Date of Baring: October 9, 2013 South Hills Reservoir I hk Foundation Engineering, Inc. Springfield, Oregon qiw page 1 of 1 Depth Soil and Rock Description Eley. A SPT, • Moisture, % Backfill/ and Log Samples N -Value Installations/ Feef Comments Depth 0 Recovery ® RQD.,% Water Table 96066 a 50 100 Loose to medium dense CRUSHED GRAVEL, grey, 959.9 Capped With 1 idirmid, t1.5 inchminus, (fll) (±g inches). I 0.8 gravel 2 Stiff gravelly CLAY, some sang brown to grey, moist_ medium plasticity, fine to coarse sang fine tocoarse, 3 subangular gravel, (fill). Sss-f �3 s56] BacIled q ____ __ ____ ____ Soft CLAY, some sang brown iron -With stained, moist, 4,0 bentonite 5 medium plasticity, fine to coarse sand (fill). p SS3-2 chips 6 953 ] Stiff to very srH sandy CLAY, trace gravel; brawn to ] o 8 light grey, iron and manganese -stained, moist, SS- -3 15 medium plasticity, fine to coarse sand, fine, 9 subangulargravel,(colluviom). 0 SS -34 g 11 12 13 S&3-5 g 14 5 3535 g 16 17 18 19 20 --\Fry _ 'ronstaineh, 9 0.] -- _ stili sandy CLAY; light grey damp 20o SS3-7 �1 _ 21 low plasticity, fine to coarse sand (residual soil). 22 23 24 25 ______ 935.7 Eremelyweak(RO) TUFF; light grey grading to 256 SS39 y D" 26 blue-grey,iron-stained, decomposed to highly Q_,> weathered. 27 28 29 j r 30 t Ss9 69 31 9292 BOTTOM OF BORING a1 s Project No.2131028-101 Boring Log: BHJ Surface Elevation: 960.7 feet (Approx.) Springfield Utility Board (SUB) Date of Boring: October 9, 2013 South Hills Reservoir 'gFoundation Engineering, Inc. Springfield, Oregon 7 Page 1 of 1 Depth Soil and Rack Description Eley. ♦ SPT, • Moisture, 4 Ba d,fifll and Log Samples N -Value Installations/ Fast Comments Depth t] Recovery ® Ron., 'A Water Table 966 6 50 00 Medium stiff to stiff clayey SILT, some sand (MHT oo Capped with 1 brown and iron and manganese -stained, moist, high cuttings plasticity, fine to coarse sand -sized rock fragments, 2 (colluvium). 3 55-14 to - Backfilled with 4 Orange -brown and iron and manganese -stained below _ bentonite 5 t5 feet. ...6 y. chips s54 2 6 7 8 S54-3 :3 9 10 _ _ _ _ ____ _ __ Medium stiff to stiff clayey SILT, some sand and 9560 16.0 SS44 �, ;7 • 11 gravel (MH); mange -brown and iron and manganese -stained, moist, medium plasticity, fine to 12 coarse sand, fine to subangular gravel -sized rock 13 fragments, (colluvium). 14 Very s[iR [a hard clayey SILT, some santl (MH); 952.2 13.a 15 yellowish brown and manganese -stained, damp to ;,. 49 moist, medium to high plasticity, fire sand, (residual SS4-5 23 16 soil). 17 18 554-7 19 -- — — -- --- EMremely weak to very weak (RO to R1) cantly _ 90].2 16.8 20 SILTSTONE; grey, slightly weathered, fine volcanic — sand. 21 _ 22 23 24 _ 5 i6 549 26 _ 9395 BOTTOM OF BORING 265 Project No.: 2211098 Boring Log: BH -4 surface Elevation: 966.0 feet (Approx.) Springfield Utility Board (SUB) Date of Boring: October 27, 2021 South Hills 3rd Level Reservoir Replacement k Foundation Engineering, Inc. Springfield, Oregon � Page 1 of 1 Depth Soil and Rock Description Elev ♦ SPT. 0 Mandate, -1, Backfill) and Log Samples IN -value installatiorisl Feet Comments Depth El Recovery ® RQD.,% Water Table 952 0 50 100 Loose to medium dense silty GRAVEL (GM); grey, 1 961.2 Capped with 1 moist, low plasticity silt, fine to coarse angular gravel, I his gravel and 2 I(fiIQ. _— — --_ ---- —J cuttings m Soft to metlium stiff clayey SILT, soe santl (MHj; 3 orange -broom and iron and manganese -stained, S&S -1 g- Backfilled moist, high plasticity, fine to medium santl-sizetl rock with 4 fragments. (colluvium). bentonite 5 -- -- _-- —___—_ 9570 chips Very stiff clayey SILT, some sm (914T yellowish s o S%2 �9 6 brawn and iron and manganese -stained, moist, medium to high plasticity, fine sand, (residual soil). 6 Relict sandstone texture below 9.5 feet. sSs-3 I A6 i - 9 10 _. SSs4 Ag� 11 Hard below 110.5 feet. 12 13 Light be. below±12.5 feet. SSS -s 53 14 15 SS -5.6i6 16 17 18 19 Bluegrey and sandy below+19 feet. 20 ______________________.... 9420 Extremely weak (ROJ silty SANDSTONE: bto" and zoo SSs] 8 1 21 iron-absned, moderately weathered, fine to medium volcanic sand. - 22 23 24 25 -------------------- ..: 9370 ..-. Very weak (R1) santly SILTSTONE; grey to dark 25.0 sss-s 26 blue -grey, slightly weathered, fine to medium volcanic _— sand. 27 28 29 _ 30- 931 s SS9 BOTTOM OF BORING -5 30.4 Project No.. 2211098 Boring Log: BH Surface Elevation: 962.0 feet (Approx.) Springfield Utility Board (SUB) Date of Boring: October 27, 2021 South Hills Springfield, 3rd Level Oregon Reservoir Replacement AhFoundation Engineering, Inc. Page 1 of Foundation Engineering, Inc. South Hills V Level Reservoir Project No.: 2211098 Photo 1 B. BH -1 Box 1 (25.0 to 33.0 feet) Photo 2B. BH -1 Box 2 (33.0 to 35.0 feet) n / 0 20 io SCALE /N FEET �svwet s� pnuG q / �ReOu/REO 1 y, r vA-t � &AVCFF AS]Y — T X AIL, 9R T6 Sa/P/eRLY — _ L1117 - Ex/sTivc. envy lx F/N/SHED .NTlx f �A TESFP/r(SEE S 2) �-- O/RECF/ON OF SORFACE ORA/NAGE C 12M "HILL TpPG6 930: I S/TE PLAN %/9'R00 �Q4 .4E'FE4ENC/NG �i I �.PVa.R LENTER- \ S rY r vA-t � &AVCFF AS]Y — T X AIL, 9R T6 Sa/P/eRLY — _ L1117 - Ex/sTivc. envy lx F/N/SHED .NTlx f �A TESFP/r(SEE S 2) �-- O/RECF/ON OF SORFACE ORA/NAGE C 12M "HILL TpPG6 930: I S/TE PLAN O PP RE S/LTY CLAY SLTY <LqY :A f Vb s/LTY CLgY W/5/jjLG 5/45'IPUE PfLCiC4 SEOY LYryY N/5 � 9J y� Gil4�LT @Y/L/1..E$` N.59L% 6IX/(Sk qNG �/CS fM1" qNO ORfif�N/ 3/t T39Ln/E /E8L 9$ 5 j w' 9d5AGT Ha(/GOG F g 11A EILTY CLYY MATRIN f- ___ _ z Ny F'F/ITHCRED i E/<T' C<dY Md /D - Mi 3/LTSTONE 5�y umEs" f I I4Ed7 lam,-M./NLAYER4� _eAAVAT/ON PLAN suevACE muc5E---' rr NOPL SUP^LY SAME TH/GA"NESS OF 5(4<Fi RECORD DRAWINGS 6RPYELLEp /LREq$. ROADWAY SEC7 /'"TMEeervs`o "Mp�vrtO"r/"anti,Hn°OoPx"W co"uNoGluPoIL°eMr`mE„Sw''"pAOi[ SEC 7-101V w°eHlulmv rtTiiS-iMEviw:lwOxE 1 NTS CHOM ::HILL s 6'S (PO 1Pi -EST PIT LOGS. RESERVOIR EXCAVATION, ROADWAY SECTION o 9J y� Gil4�LT @Y/L/1..E$` N.59L% 6IX/(Sk qNG �/CS fM1" qNO ORfif�N/ aqq' f` �AASL TOCLdYd j 6ASAIT L'OL+iLERS F g 11A EILTY CLYY MATRIN f- w� /D - Fs¢yJSy_ umEs" L W/i // N/ JL/N A�EREw355 C'ICKIA'la Nil3LYFT NJCKf! '15.. e TME 4"rTt/ OfTHE +ME.t/y: E EETNEW Sdt TYFYf /S M^RW%hNTE rIND ]F.ANS T/ONG YMY EIE GRyIX/ryG 3 M1'K GW.1T/D/.L SEE 5/TE PLryN N Sl(l SbGE OF 4. NO W.iTER WAS 09SERVEO /N ANY EST P/T O HER T/{AN PoNNMT/pN"� TP/O. $EASON/IL N1R/dT/ONS ARE EXPECTED 5. THE CdGS SHOW 5(/65U5FAf£ fdyO/TONS M'LY RT TN£ T/n!E RNO H.10E ry/E TEST PI ]5 WERE Ay➢E. I4Ed7 lam,-M./NLAYER4� _eAAVAT/ON PLAN suevACE muc5E---' rr NOPL SUP^LY SAME TH/GA"NESS OF 5(4<Fi RECORD DRAWINGS 6RPYELLEp /LREq$. ROADWAY SEC7 /'"TMEeervs`o "Mp�vrtO"r/"anti,Hn°OoPx"W co"uNoGluPoIL°eMr`mE„Sw''"pAOi[ SEC 7-101V w°eHlulmv rtTiiS-iMEviw:lwOxE 1 NTS CHOM ::HILL s 6'S -EST PIT LOGS. RESERVOIR EXCAVATION, ROADWAY SECTION ane[i .t m . ox. we ue, mo p P4 S/LTY CUY -P. y}� W6 5 2Tr euYSV/sNnee smrsravC PJe;LEs .; M V d B¢VG U£R5, a9 d fvEHTi:UREp I`� i l MI S/LTsrpNE H4sfCT CA/LLIPAS .a✓o aevpvres eN59LT 6CULL1'A5' ov.' •R/o G.ea�Nlcr :1: _ P1JS'ER dGG/N6 A' T1 ]RL T] 1 S/LTY !//IY dIS9LT /E2S CICS RAID Gtr.{NiCS I 1 S/i T3TONEYIYdGGE3L Zrp S/C TYCLgY da �V1KAS emcn£as B¢VG U£R5, a9 I6414�1A114 OF T UM UP TO 4' plq. /N A5/LTY CLAY I TO VPi TO 9'INO A.DF L R -RTP CGb MATRIX H4sfCT CA/LLIPAS .a✓o aevpvres eN59LT 6CULL1'A5' ov.' •R/o G.ea�Nlcr :1: _ P1JS'ER dGG/N6 A' � Vi Oq dTAEOULAU�TEVP SRNO RfATR/X . ZBS' ( TES/p�WERE EM>l`HT6'J dJ CK!EMGEF H./S3 % lw q ./OKN MERE 555 OnCKF W/TNA L fT 4'MKET S THE ca lw W WE INT£RryO, `%er N SGG TYrYS AS S. % 0.1"OU SEE vw A,~ or/ I GRryC;ViJG 4 AS WRTER WAS .6 . W ANY TEST P/T ¢TI!£T THAN TP -/O.. ..VARTd T/ONS AR£ EXPECTED 5 THE LGGS S3IOW SUBSURFACE CaVO/TYONS ONLY AT T]/E T/ME ANO PLACE THE TEST A/ WEPE IMDE. TEST P/T LOGS R£an EX/sT/ G,(bUNZ,C EX/ST.`NG—. /f/� �yE_ OG3FF-TFZa ��iy GROUND -• _--.� _ 9'M/N GAYER QE -c"AAN CAPER OF 9U/PF/IG'E COVRGE-� LR/IVEC EASE COURSE OTE: Y SAME TH/CKNESS OG SURfMC/NG pIJ RLL GRgVELLEO PREAs ROACWAY SELT/ON SECT/ON B\ K?S / 4 G a G s CH2A1UHILL aR Lw'a MOTES: 1. CLEAR ALL GROUND WITHIN THE NORTH AND SOUTH CLEARING LIMITS EXCEPT FOR TREES LARGER THAN fi' DIAMETER WHICH AREWESTERLV OF THE PROPOSED WEST FENCE LINE AND OUTSIOETHEROAOWAV. 2 EXGAVATETHERESERVOIR AREATOTHELINESANDGRADES SHOWN. THE EXCAVATED MATERIAL SHALL BE STOCKPILED OFF SITE PER SPECIFICATIONS AND AS OIPEGTE'J BY THE ENGINEER. N04THERGY cLEgR/NG G/M/T T'SVP OV` sLO SLOPE AS RC --- q WD SOUTH OF. SERVWR RESERV01,f EXCAVATION PLAN �x20._px RECORD DRAWINGS iu Ecapo opxwlu¢s XAVE6EEU GRE.I,gm. IN PART. ONI ♦HE BMIN OF WFpgME➢ON COMPrtm BV OTHEPS MEV Aq4 TOAEHIESEM M.ETAN, EFWTWCATION IYGE IX COMPON¢NT Nap YINNEP OF GONAquCTION HE -SWIEp INLL NW BE pETPoNSNpOLGpaq ApY EppaRi Op ao°ohiwlxlCCs. HNVE aEEII FppATm INTO 1NE iS MG SPRINGFIELD IITILITV REGERNO. I TEST PIT LOGS, RESERVOIR EXCAVATION/ ORRO SPRIN.NS O, OPFGOx ROADWAY SECTION AS ' O a9 L ' H4sfCT CA/LLIPAS .a✓o aevpvres eN59LT 6CULL1'A5' ov.' •R/o G.ea�Nlcr 40° t1j.41t? �.•LSEES Vi .wo ceGANlas y'�p JC 'b OgSAGT B¢ULGE4S - 6g5yGT BOVLQ�ES NJ /J ®AA S/LT, 1C 1 MATP/Y j SNA S/LTY CLAY A.Mix SILJY CLHY ✓H%�!k S YY 4� I CRV%M .Q SILTY C[hY 't 7tT eOL/LL1FR5 /p _ ' U, III, VATU 3'O/A. . ZBS' ( TES/p�WERE EM>l`HT6'J dJ CK!EMGEF H./S3 % lw q ./OKN MERE 555 OnCKF W/TNA L fT 4'MKET S THE ca lw W WE INT£RryO, `%er N SGG TYrYS AS S. % 0.1"OU SEE vw A,~ or/ I GRryC;ViJG 4 AS WRTER WAS .6 . W ANY TEST P/T ¢TI!£T THAN TP -/O.. ..VARTd T/ONS AR£ EXPECTED 5 THE LGGS S3IOW SUBSURFACE CaVO/TYONS ONLY AT T]/E T/ME ANO PLACE THE TEST A/ WEPE IMDE. TEST P/T LOGS R£an EX/sT/ G,(bUNZ,C EX/ST.`NG—. /f/� �yE_ OG3FF-TFZa ��iy GROUND -• _--.� _ 9'M/N GAYER QE -c"AAN CAPER OF 9U/PF/IG'E COVRGE-� LR/IVEC EASE COURSE OTE: Y SAME TH/CKNESS OG SURfMC/NG pIJ RLL GRgVELLEO PREAs ROACWAY SELT/ON SECT/ON B\ K?S / 4 G a G s CH2A1UHILL aR Lw'a MOTES: 1. CLEAR ALL GROUND WITHIN THE NORTH AND SOUTH CLEARING LIMITS EXCEPT FOR TREES LARGER THAN fi' DIAMETER WHICH AREWESTERLV OF THE PROPOSED WEST FENCE LINE AND OUTSIOETHEROAOWAV. 2 EXGAVATETHERESERVOIR AREATOTHELINESANDGRADES SHOWN. THE EXCAVATED MATERIAL SHALL BE STOCKPILED OFF SITE PER SPECIFICATIONS AND AS OIPEGTE'J BY THE ENGINEER. N04THERGY cLEgR/NG G/M/T T'SVP OV` sLO SLOPE AS RC --- q WD SOUTH OF. SERVWR RESERV01,f EXCAVATION PLAN �x20._px RECORD DRAWINGS iu Ecapo opxwlu¢s XAVE6EEU GRE.I,gm. IN PART. ONI ♦HE BMIN OF WFpgME➢ON COMPrtm BV OTHEPS MEV Aq4 TOAEHIESEM M.ETAN, EFWTWCATION IYGE IX COMPON¢NT Nap YINNEP OF GONAquCTION HE -SWIEp INLL NW BE pETPoNSNpOLGpaq ApY EppaRi Op ao°ohiwlxlCCs. HNVE aEEII FppATm INTO 1NE iS MG SPRINGFIELD IITILITV REGERNO. I TEST PIT LOGS, RESERVOIR EXCAVATION/ ORRO SPRIN.NS O, OPFGOx ROADWAY SECTION Appendix C Laboratory Testing Foundation Engineering, Inc. Professional Geotechnical Services Foundation Engineering, Inc. South Hills 3rd Level Reservoir Replacement Pro act No.: 2211098 Table 1 C. Moisture Contents (ASTM D 2216) and Atterberg Limits (ASTM D 4318) Sample Number Sample Depth (ft) Moisture Content (%) Atterberg Limits USCS Classification LL PL PI SS -3-4 10.0 - 11.5 58.4 48 37 MH SS -4-1 2.5-4.0 38.9 34 31 MH SS -4-2 5.0- 6.5 43.3 P67 SS -4-3 7.5 - 9.0 41.9 SS -4-4 10.0- 11.5 54.0 SS -4-5 12.5 - 14.0 65.4 SS -4-6 15.0- 16.5 54.4 SS -4-7 17.5 - 19.0 43.9 SS -5-1 2.5 - 4.0 43.1 SS -5-2 5.0-6.5 64.4 SS -5-3 7.5 -9.0L45. 78 47 31 MH SS -5-4 10.0- 11.5SS-5-5 12.5 - 14.0SS-5-6 15.0- 16.5 di Ek Appendix D Seismic Hazard Study Foundation Engineering, Inc. Professional Geotechnical Services SEISMIC HAZARD STUDY SOUTH HILLS 3RD LEVEL RESERVOIR REPLACEMENT SPRINGFIELD, OREGON INTRODUCTION This seismic hazard study was completed to identify potential geologic and seismic hazards and evaluate the effect those hazards may have on the proposed project. The study fulfills the requirements presented in the 2019 Oregon Structural Specialty Code (OSSC), Section 1803 for site-specific seismic hazard reports for essential and hazardous facilities and major and special -occupancy structures (OSSC, 2019). The 2019 OSSC is based on the 2018 International Building Code and ASCE 7-16. The following sections provide a discussion of the local and regional geology, seismic and tectonic setting, earthquakes, and seismic hazards. A detailed discussion of the subsurface conditions at the project location, including exploration logs, is provided in the main report. The project site currently has an existing 98 -foot diameter concrete reservoir tank designated as Reservoir No. 1. A proposed, new, 57 -foot diameter steel tank (designated as Reservoir No. 2) is planned to the west of Reservoir No. 1. Once Reservoir No. 2 is built, Reservoir No. 1 will be demolished and a new reservoir (designated as Reservoir No. 3) will be built in its place. Reservoir No. 3 will be a 67 -foot diameter steel tank consistent with Reservoir No. 2. This report is focused on the area that will include Reservoir No. 2 and Reservoir No. 3. LITERATURE REVIEW We reviewed available geologic, seismic, and hazard publications and maps to characterize the local and regional geology and evaluate relative seismic hazards at the site. We also reviewed information from geotechnical and seismic hazard investigations previously conducted by Foundation Engineering for Reservoir No. 1 and the South Hills 4th Level Reservoir located upslope. As -built plans for Reservoir No. 1 were also reviewed. Regional Geology Springfield is located within the eastern edge of the Southern Willamette Valley, which is a broad, north -south -trending basin separating the Coast Range to the west from the Cascade Range (Western and High Cascade Ranges) to the east. The project site is along the western foothills of the Western Cascades where it transitions to the southern extent of the Willamette Valley. At the western margin of Oregon is the Cascadia Subduction Zone (CSZ). The CSZ is a converging, oblique plate boundary where the Juan de Fuca oceanic plate is being subducted beneath the western edge of the North American continental plate (Geomatrix Consultants, 1995). The CSZ extends from central Vancouver Island, in British Columbia, Canada, through Washington and Oregon to Northern California in the United States (Atwater, 1970). The movement of the subduction zone has South Hills 3rd Level Reservoir Replacement November 23, 2021 Seismic Hazard Study 1 Project No.: 2211098 Springfield, Oregon Springfield Utility Board resulted in accretion, folding, faulting, and uplift of oceanic and other sediments on the western margin of the North American plate. In the early Eocene (±55 million years ago), the present location of the Willamette Valley was part of a broad continental shelf extending west from the Western Cascades beyond the present coastline (Orr and Orr, 1999). Basement rock underlying most of the north -central portion of the Valley includes the Siletz River Volcanics (early to middle Eocene, ±50 to 58 million years old), which erupted as part of a submarine oceanic island -arc (Bela, 1979; Yeats at al., 1996). The thickness of the basement volcanic rock is unknown; however, it is estimated to be ±3 to 4 miles thick (Yeats at al., 1996). The island -arc collided with, and was accreted to, the western margin of the converging North American plate near the end of the early Eocene. Volcanism subsided and a forearc basin was created and infilled to the south with marine sediments of the Eugene Formation and terrestrial sedimentary and volcanic deposits of the Fisher Formation and Little Butte Volcanics throughout the late Eocene and Oligocene (Orr and Orr, 1999; Wiley, 2008). These sediments typically overlie but are also interbedded with younger Tertiary volcanics in the Springfield area. After emerging from a gradually shallowing ocean, the marine sediments and volcanic formations were covered by the terrestrial Columbia River Basalt (CRB). The CRIB poured through the Columbia Gorge from northeastern Oregon and southeastern Washington and spread as far south as Salem, Oregon (± 17 to 10 million years ago, middle to late Miocene) (Tolan et al., 2000). Uplift and folding of the Coast Range and the Western Cascades during the late Miocene formed the trough-like configuration of the Willamette Valley (Orr and Orr, 1999; O'Connor at al., 2001; Wiley, 2008; McClaughry et al., 2010). Following the formation of the Willamette Valley, thick layers of Pliocene gravel filled the Southern Valley (McClaughry at al., 2010). The deposits were then incised by the Willamette River, forming alluvial terraces. In the Pleistocene (±1.6 million to 10,000 years ago), the Central and Southern Valley was refilled with fan -delta gravel, originating from the melting glaciers in the Cascade Range. The Willamette and McKenzie Rivers in the Springfield area incised deeply into the fan -delta deposits during the Quaternary and deposited recent alluvium adjacent to the river banks and along major tributaries (Madin and Murray, 2006). Local Geology The reservoirs are located on bench on a north -facing slope at the southeast edge of Springfield. The project site located is down slope (north) from the newly constructed South Hills 4th Level Reservoir and Jessica Drive. Local geologic mapping and cross-sections indicate the project site and immediate surrounding area is generally underlain by volcaniclastic bedrock (Yeats at al., 1996; Hladky and McCaslin, 2006; McClaughry et al., 2010). Landslide deposits have been mapped in the vicinity of the site and are shown on the Oregon Department of Geology and Mineral Industries (DOGAMI) SLIDO and HazVu web viewers. South Hills 3rd Level Reservoir Replacement November 23, 2021 Seismic Hazard Study 2 Project No.: 2211096 Springfield, Oregon Springfield Utility Board The subsurface conditions in our explorations are generally consistent with the geologic mapping. Colluvial soils were encountered in each of the explorations extending to depths of up to ±20 feet below the ground surface. Colluvium consists of material that has been transported downslope and deposited via erosion, creep, or landslide activity. Based on the terrain, we anticipate the colluvium was likely deposited as a result of previous landslide activity. The colluvium consists of predominantly sandy clay, sandy silt, or clayey silt with sand to boulder -sized basaltic rock fragments. Basaltic cobble and boulder -sized rock fragments were observed in the cut slope on the south side of Reservoir No. 1 and in the fill stockpiled on the proposed Reservoir No. 2 site. We anticipate the stockpiled fill was excavated from the Reservoir No. 1 site. Colluvium including cobble to boulder -sized rock fragments was also encountered in our previous test pits and boring completed up slope for the new South Hills 4th Level reservoir. The colluvium is typically underlain by residual soil (i.e., bedrock that has decomposed in place to the consistency of soil) followed by tuff, siltstone, sandy siltstone, and silty sandstone. A boring (ES9) and accompanying shear wave velocity log were completed near 70th Street and Ivy Street (±2,000 feet southeast of the site) in 1996 by DOGAMI. This boring was part of a shear wave velocity study of the Eugene -Springfield area (Wang at al., 1998). Subsurface conditions at ES9 included fill and landslide deposits (colluvium) followed by vitric tuff below ±18.5 feet. The recorded shear wave velocities at ES9 included 387 feet/second Ift/s) extending to ±8 feet, 1,092 ft/s in the colluvium extending to ± 18.5 feet, and 1,989 ft/s in the vitric tuff to ±29.5 feet (Wang at al., 1998). The shear wave velocities at ES9 should be fairly comparable to the South Hills 3rd Level Reservoir site. Details are provided in the Subsurface Conditions section of the main report, cross-sections in Appendix A, and on the boring logs in Appendix B. Seismic Setting and Local Faulting We completed a literature review of faults to evaluate the seismic setting and identify the potential seismic sources. The US Geological Survey (USGS) website includes an interactive deaggregation tool, which allows evaluation of the contribution of the various seismic sources to the overall seismic hazard (USGS, 2014). The USGS interactive deaggregation indicates the seismic hazard at the site is dominated by the CSZ (USGS, 2014). Crustal faults also represent a potential seismic hazard. A discussion of these earthquake sources is provided below. Cascadis Subduction Zone /CSZ/. The site is ± 120 miles east of the surface expression of the CSZ and the subduction zone extends beneath the site at an estimated depth of about 31 miles. The CSZ is a converging, oblique plate boundary where the Juan de Fuca plate is being subducted beneath the western edge of the North American plate. It is estimated the average rate of subduction of the Juan de Fuca plate under the North American plate is ±37 mm/year northeast, based on Pacific and Mid -Ocean Ridge velocities, geodetic studies of convergence, and magnetic anomalies of the Juan de Fuca plate (Personius and Nelson, 2006; DeMets et al., 2010). The CSZ extends ±700 miles from central Vancouver Island in British Columbia, Canada, through Washington and Oregon to Northern California (Atwater, 1970). South Hills 3m! Level Reservoir Replacement November 23, 2021 Seismic Hazard Study 3 Pm2ct No., 2211098 Springfield, Oregon Springfield Utility Board Crustal Fauns. Crustal faults are fractures within the North American plate. Numerous faults are presented on local and regional geologic maps. However, not all faults are considered to be active. Because the historical earthquake record is so short, active faults are identified by geologic mapping and seismic surveys. The USGS has defined four fault classifications based on evidence for displacement within the Quaternary (<1.6 million years) in their US fault database (Palmer, 1983; Personius et al., 2003). The fault classes are defined as follows: • Class A - Faults with geologic evidence supporting tectonic movement in the Quaternary known or presumed to be associated with large -magnitude earthquakes. • Class 8 - Faults with geologic evidence that demonstrates the existence of a fault or suggests Quaternary deformation, but either: 1) the fault might not extend deep enough to be a potential source of significant earthquakes or 2) the current evidence is too strong to confidently classify the fault as a Class C but not strong enough to classify it as a Class A. • Class C - Faults with insufficient evidence to demonstrate 1) the existence of a tectonic fault, or 2) Quaternary movement or deformation associated with the feature. • Class D - Geologic evidence indicates the feature is not a tectonic fault or feature. Class A and B faults are included in the USGS fault database and interactive fault map. USGS considers 17 features in Oregon to be Class C faults (USGS, 2006a), including Harrisburg anticline located ±21 miles northwest of the site. The USGS does not consider any features in Oregon as Class D (USGS, 2006a). Local geologic maps indicate no crustal faults mapped beneath the site (Yeats at al., 1996; Hladky and McCaslin, 2006). The site is located between approximate to concealed crustal faults that have been mapped less than 1 mile of the site (Hladky and McCaslin, 2006). However, none of the nearby faults show any evidence of movement in the last ± 1.6 million years (Palmer, 1983; Geomatrix Consultants, 1995; Personius et al., 2003; USGS, 2006a). Six potentially active Quaternary Class A and B crustal fault zones have been mapped by the USGS within ±50 miles of the site (Palmer, 1983; Geomatrix Consultants, 1995; Personius at al., 2003; USGS, 2006a). These faults are listed in Table 1 D. Figure 1 D shows the approximate surface projection locations of these faults. South Hills 3rd Level Reservoir Replacement November 23, 2021 Seismic Hazard Study 4 Pro act No.: 2211098 Springfield, Oregon Springfield Utility Board Table 1 D. USGS Class A and Class B Crustal Faults within a± 50 -mile Radius of the Site 11( i9 Fault data based on Persodus at al., 2003 and USGS, 2006a and b. Isl Distance and direction from site to nearest surface projection of the crustal fault. isl Quaternary time period defined at <1.6 million years based on the 1983 Geologic Time Scale (Palmer, 1983). Historic Earthquakes Available information indicates the CSZ is capable of generating earthquakes along the inclined interface between the two plates (interface) and within the descending Juan de Fuca plate (intraplate) (Weaver and Shedlock, 1996). The fault rupture may occur along a portion or the entire length of the CSZ (Weaver and Shedlock, 1996). CSZ Interface Earthquakes. The estimated maximum magnitude of a CSZ interface earthquake is up to a moment magnitude (Mw) 9.3 (Petersen et al., 2014). No significant interface (subduction zone) earthquakes have occurred on the CSZ in historic times. However, several large -magnitude (>M —8.0, M = unspecified magnitude scale) subduction zone earthquakes are thought to have occurred in the past few thousand years. This is evidenced by tsunami inundation deposits, combined with evidence for episodic subsidence along the Oregon and Washington coasts (Peterson et al., 1993; Atwater of al., 1995). Numerous detailed studies of coastal subsidence, tsunami, and turbidite deposits have been conducted to develop a better understanding of CSZ earthquakes. The studies include investigations of turbidite deposits in the offshore Cascadia Basin that were used to help develop a paleoseismic record for the CSZ and estimate recurrence intervals for interface earthquakes (Adams, 1990; Goldfinger at al., 2012). Study of offshore turbidites from the last ±10,000 years suggests the return period for South Hills 3rd Level Reservoir Replacement November 23, 2021 Seismic Hazard Study 5 Project No.: 2211098 Springfieltl, Oregon Springfield Utility Board Approximate Approximate Last Known Fault Name Fault Distance and Slip Rate and Class Number Length Directien from Site Deformation (a) larval (miles) (miles) (21 (Yeats) Upper Willamette 863 ±27 ±33 BE <1.6 million <0.20 River IBI Owl Creek (A) 870 ±9 ±34 N -NW <750,000 <0.20 Corvallis (B) 869 ±25 ±41 NW <1.6 million <0.20 Unnamed faults 862 ±17 ±44 S -SW <750,000 <0.20 near Sutherlin (B) White Branch 1809 ±11 ±46 E <750,000 <0.20 fault zone (A) Salem-Eola Hills 719 ±20 ±50 N <1.6 million <0.20 homocline (A) i9 Fault data based on Persodus at al., 2003 and USGS, 2006a and b. Isl Distance and direction from site to nearest surface projection of the crustal fault. isl Quaternary time period defined at <1.6 million years based on the 1983 Geologic Time Scale (Palmer, 1983). Historic Earthquakes Available information indicates the CSZ is capable of generating earthquakes along the inclined interface between the two plates (interface) and within the descending Juan de Fuca plate (intraplate) (Weaver and Shedlock, 1996). The fault rupture may occur along a portion or the entire length of the CSZ (Weaver and Shedlock, 1996). CSZ Interface Earthquakes. The estimated maximum magnitude of a CSZ interface earthquake is up to a moment magnitude (Mw) 9.3 (Petersen et al., 2014). No significant interface (subduction zone) earthquakes have occurred on the CSZ in historic times. However, several large -magnitude (>M —8.0, M = unspecified magnitude scale) subduction zone earthquakes are thought to have occurred in the past few thousand years. This is evidenced by tsunami inundation deposits, combined with evidence for episodic subsidence along the Oregon and Washington coasts (Peterson et al., 1993; Atwater of al., 1995). Numerous detailed studies of coastal subsidence, tsunami, and turbidite deposits have been conducted to develop a better understanding of CSZ earthquakes. The studies include investigations of turbidite deposits in the offshore Cascadia Basin that were used to help develop a paleoseismic record for the CSZ and estimate recurrence intervals for interface earthquakes (Adams, 1990; Goldfinger at al., 2012). Study of offshore turbidites from the last ±10,000 years suggests the return period for South Hills 3rd Level Reservoir Replacement November 23, 2021 Seismic Hazard Study 5 Project No.: 2211098 Springfieltl, Oregon Springfield Utility Board interface earthquakes varies with location and rupture length. That study estimated an average recurrence interval of ±220 to 380 years for an interface earthquake on the southern portion of the CSZ, and an average recurrence interval of ±500 to 530 years for an interface earthquake extending the entire length of the CSZ (Goldfinger et al., 2012). Older, deep-sea cores have been re-examined more recently, and the findings may indicate greater Holocene stratigraphy variability along the Washington coast (Atwater et al., 2014). Additional research by Goldfinger for the northern portion of the CSZ suggests a recurrence interval of ±340 years for the northern Oregon Coast (Goldfinger et al., 2016). The most recent CSZ interface earthquake occurred ±321 years ago (January 26, 1700) (Nelson et al., 1995; Satake at al., 1996). CSZlntraplate Earthquakes. Intraplate (Intraslab or Wadati-Benioff Zone) earthquakes occur within the Juan de Fuca plate at depths of ±28 to 37 miles (Weaver and Shedlock, 1996). The maximum estimated magnitude of an intraplate earthquake is about Mw 7.5 (Petersen et al., 2014). The available record for intraplate earthquakes in Oregon is limited. The available data indicates a Mb = 4.6 (compressional body wave magnitude) event occurred in 1963, located ±23 miles east of Salem at a depth of ±29 miles (Barnett et al., 2009). Based on its depth, this earthquake may be considered an intraplate event. The Puget Sound region of Washington State has experienced three intraplate events in the last ±72 years, including a surface wave magnitude (M.) 7.1 event in 1949 (Olympia), a Ms 6.5 event in 1965 (Seattle/Tacoma) (Wong and Silva, 1998), and a Mw 6.8 event in 2001 (Nisqually) (Dewey et al., 2002). Crustal Earthquakes. Crustal earthquakes dominate Oregon's seismic history. Crustal earthquakes occur within the North American plate, typically at depths of ±6 to 12 miles. The estimated maximum magnitude of a crustal earthquake in the Willamette Valley and adjacent physiographic regions is about Mw 7.0 (Petersen et al., 2014). Only two historic crustal events in Oregon have reached Richter local magnitude (ML) 6 (the 1936 Milton-Freewater ML 6.1 earthquake and the 1993 Klamath Falls Mi 6.0 earthquake) (Wong and Bott, 1995). The majority of Oregon's larger crustal earthquakes are in the Mi 4 to 5 range (Wong and Bott, 1995). Table 2D summarizes earthquakes with a M of 4.0 or greater or Modified Mercalli Intensity (MMI) of V or greater, that have occurred within a ±50 -mile radius of Springfield in the last ±188 years (Johnson et al., 1994; USGS, 2013). Note that the referenced earthquake catalogs are a composite of different earthquake catalogs and seismic networks; therefore, data errors may exist. Complete historic earthquake records may not yet be included in the referenced earthquake catalogs. Therefore, it is possible some earthquakes may not be included in Table 2D. South Hills 3rd level Reservoir Replacement November 23, 2021 Seismic Hazard Study 6 Project No.: 2211098 Springfield, 01.1.1 Springfield Utility Board Table 2D. Historic Earthquakes Within a ± 50 -mile Radius of Springfield "1 Year Month Day Hour Minute Latitude Longitude Depth (miles) Magnitude or Intensity (1) 1921 02 25 20 00 44.4 -122.4 unknown MMI — v 1942 05 13 01 52 44.5 -123.3 unknown MMI = v 1961 08 19 04 56 44.7 -122.5 unknown M = 4.5 2015 07 04 15 42 44.1 -122.8 5.0 Me = 4.1 I The site is located at Latitude 44.034716, Longitude -122.909738. of M = unspecified magnitude, Mb =compressional body wave magnitude, M, = primary coda magnitude, Mr = local Richter magnitutle, and MMI = Modified Memalli Intensity at or near epicenter. Seismic events in Oregon were not comprehensively documented until the 1840s (Wong and Bott, 1995). Earthquake epicenters located in Oregon from the late 1920s to 1962 were limited due to the number of and the distance between seismographs, the number of recording stations, and uncertainty in travel times. Therefore, information recorded during that time suggests only earthquakes with magnitudes >5 would be recorded in Oregon (Bela, 1979). Oregon State University (OSU) likely had the first station installed in 1946, and the first modern seismograph was installed at OSU in 1962 (Wong and Bott, 1995; Barnett at al., 2009). According to Wong and Batt (1995), seismograph stations sensitive to smaller earthquakes (ML <4 to 5) were not implemented in northwestern Oregon until 1979 when the University of Washington expanded their seismograph network to Oregon. The local Richter magnitude (ML) of events occurring prior to the establishment of seismograph stations have been estimated based on correlations between magnitude and MMI. Some discrepancy exists in the correlations. Table 3D summarizes distant, strong earthquakes felt in the Springfield area (Noson at al., 1988; Bott and Wong, 1993; PNSN, 1993; Stover and Coffman, 1993; Wong and Bott, 1995; PNSN, 2001). None of these events caused significant, reportable damage in Springfield or surrounding area. Heplacement Seismic Hazard Study Springfield, Oregon Table 3D. Distant Earthquakes Felt in the Springfield Area Earthquake Modified Memalli Intensities (MMI) 2001 Nisqually, Washington II to III 1993 Klamath Falls, Oregon IV 1993 Scotts Mills, Oregon IV 1965 Seattle - Tacoma, Washington I to IV 1962 Portland, Oregon I to IV 1961 Lebanon/Albany, Oregon IV 1949 Olympia, Washington IV 1873 Crescent City, California V Seismic and Geologic Hazards Section 1803.6.1 of the OSSC 2019 requires the evaluation of risks from a range of seismic hazards including landslides, earthquake -induced landslides, liquefaction and lateral spread, seismic -induced settlement or subsidence, fault rupture, earthquake - induced flooding and inundation, and local ground motion amplification (OSSC, 2019). We have developed conclusions regarding the seismic hazards based on the subsurface profiles encountered in the explorations completed at the project site. The conclusions are also based on our knowledge of the site geology, a review of previous geotechnical and seismic studies performed at the site and in the vicinity, and available geologic hazard maps (including information available from DOGAMO. DOGAMI has completed geologic and seismic hazard studies, which include Lane County and Eugene -Springfield (Black at al., 2000; Burns et al., 2008; Calhoun et al., 2018), and provides online hazard information through HazVu, LiDAR, and SLIDO viewers (DOGAMI, 2018, 2O20a, b). The above-mentioned maps and viewers refer to some, but do not cover all of the seismic hazards. The information available from DOGAMI is only considered a guide and does not have precedence over site-specific evaluations. In the following sections, information from the available seismic hazard maps is provided along with our site-specific evaluations for comparison. The relative earthquake hazard is based on the combined effects of ground shaking amplification and earthquake -induced landslides with a range in hazard from Zone A (highest hazard) to Zone D (lowest hazard). The relative earthquake hazard in the vicinity of the Reservoirs is mapped as Zone B (intermediate to high hazard) likely due to the Reservoirs being located in an area mapped as existing landslide deposits (Black et al., 2000; Hladky and McCaslin, 2006). South Hills 3rd Level Reservoir Replacement November 23, 2021 Seismic Hazard Study a Pro per No.: 2211098 Springfield, Oregon Springfield Utility Board Landslides and Earthquake-Mduced Landslides. DOGAMI references including SLIDO and HazVu web viewers indicate the area is mapped as landslide terrain (Hladky and McCaslin, 2006; Calhoun at al., 2018; DOGAMI, 2018, 20206). A mapped landslide extends across the site with the headscarp located ±800 to 1,200 feet to the south (uphill) and landslide debris extending up to ±3,500 feet to the north (downhill). A series of smaller scarps are mapped uphill and downhill of the reservoir site. DOGAMI estimates the mapped landslide to be more than 150 years old (Calhoun at al., 2018). LiDAR imagery shows relatively smooth, gentle to moderate slopes for most of the site (DOGAMI, 2020a). We completed a reconnaissance of the reservoir site including the slopes immediately uphill and downhill of the existing and proposed tanks. We did not observe any signs of recent or active slope instability. We understand Reservoir No. 1 was built in 1981 and no landslide related issues have impacted Reservoir No. 1 to date. Any development within hillside terrain includes inherent risk of slope instability, particularly hillside terrain with mapped landslide topography. However, no recent or on-going active slope instability features were observed during the exploration phase. The existing and proposed reservoirs are sited on a relatively wide bench that is underlain by predominantly stiff to hard soil and shallow bedrock that has a relatively flat surface. Based on our observations, soil and rock conditions, and the results of the slope stability analysis (discussed in the main report), we believe the risk of landslides or earthquake -induced landslides (with design -level earthquake loads) occurring at the site is low. Investigating the potential for movement on the large, mapped slide extending downhill and uphill of the site is a complex and uncertain process and is not within the scope of this investigation. Liquefaction, Settlement, and Lateral Spread. Soil liquefaction occurs when loose, saturated cohesionless soil experiences a significant loss of strength during strong ground shaking. The strength loss is associated with rapid densification of the soil and corresponding development of high pore water pressure, which can lead to the soil behaving like a viscous fluid. Liquefiable soils typically consist of saturated, loose, clean sand and non -plastic to low plasticity silt with a plasticity index (PI) typically less than 8. The colluvium and residual soil underlying the site are comprised of predominantly fine-grained soil with medium to high plasticity. These soils are not susceptible to liquefaction. Therefore, we have concluded there is no liquefaction hazard at the project site. The DOGAMI hazard report and HazVu site indicate liquefaction susceptibility is moderate in the project area (Burns at al., 2008; DOGAMI, 2018). Lateral spread is a liquefaction -induced hazard, which occurs when soil or blocks of soil are displaced down slope or toward a free face (such as a riverbank) along a liquefied layer. The lateral spread hazard does not exist at the site due to the absence of a liquefaction hazard. South Hills 3rd Loyd Reservoir Replacement November 23, 2021 Seismic Hazard Study 9 Pm ect No.: 2211098 Springfield, Oregon Springfield Utility Board Subsidence. Ground subsidence is a regional phenomenon resulting from a large magnitude CSZ earthquake. It occurs because the subduction of the oceanic crust beneath the continental crust compresses the continental crust and pushes it upward. Prior to the earthquake, the continental crust is held in this position by friction at the CSZ interface. When the earthquake occurs, that frictional bond breaks allowing the continental crust to drop. The subsidence hazard map included in the Oregon Resilience Plan (OSSPAC, 2013), indicates the ground subsidence in the Springfield area during a Me 9 CSZ earthquake could be up to 1 foot. Ground subsidence cannot be mitigated. Therefore, it should be assumed the site and surrounding area could drop by up to 1 foot during a large magnitude CSZ earthquake. Fault Rupture. The risk of fault rupture is expected to be low due to the lack of known active crustal faulting beneath the site (Personius at al., 2003; Hladky and Mc Caslin, 2006; USGS, 2OO6b, a; McClaughry et al., 2010). The closest potentially active (Class A) crustal fault is the Owl Creek fault, which is ±34 miles north-northwest of the site. Tsunami/Seiche/Earthouake-Induced Flooding. Tsunami are waves created by a large- scale displacement of the sea floor due to earthquakes, landslides, or volcanic eruptions (Priest, 1995). Tsunami inundation is not applicable to this site because Springfield is not on the Oregon Coast. Seiche (the back and forth oscillations of a water body during a seismic event) is also not a local hazard due to the absence of large bodies of water near the site. According to HazVu, there is no localized flood potential for the Effective FEMA 100 -year flood at or near the site (DOGAMI, 2018). Earthquake -induced flooding related to the failure of other structures (e.g., dams) or shallow groundwater and subsidence does not apply to the site. Local Ground Motion Ampli>ication. Ground motion amplification is the influence of a soil deposit on the earthquake motion. As seismic energy propagates up through the soil strata, the ground motion is typically increased (i.e., amplified) or decreased (i.e., attenuated) to some extent. The site is underlain by medium stiff to hard colluvium and residual soil followed by relatively shallow bedrock. Based on the site conditions, we have concluded the amplification hazard is relatively low and is consistent with an OSSCIIBC Site Class C (i.e., very dense soil and soil rock). The DOGAMI hazard studies indicate the amplification susceptibility for the site is low (NEHRP Site Class B) (Black et al., 2000; Burns at al., 2008). Although the amplification hazard is low, the site is expected to experience strong ground shaking during a CSZ earthquake due to its proximity to the CSZ (DOGAMI, 2018). See the main report for more discussion on the site response. South Hills Set Level Reservoir Replacement November 23, 2021 Seismic Hazard Study 10 Project No.: 2211098 Springfield, Oregon Springfield Utility Board SEISMIC DESIGN Design Earthquakes The OSSC 2019, Section 1803.3.2.1, requires the design of structures classified as essential or hazardous facilities and of major and special occupancy structures to address, at a minimum, the following earthquakes: Crustal: A shallow crustal earthquake on a real or assumed fault near the site with a minimum Mw 6.0 or the design earthquake ground motion acceleration determined in accordance with the OSSC 2019 Section 1613. Intraplate: A CSZ intraplate earthquake with Mw of at least 7.0. Interface: A CSZ interface earthquake with a Mw of at least 8.5. The design maximum considered earthquake ground motion maps provided in the OSSC 2019, are based on modified (risk -targeted) 2014 maps prepared by the USGS for an earthquake with a 2% probability of exceedance in 50 years (i.e., a ±2,475 -year return period) for design spectral accelerations (USGS, 2014). The modifications include factors to adjust the spectral accelerations to account for directivity and risk. The 2014 USGS maps were established based on probabilistic studies and include aggregate hazards from a variety of seismic sources. The USGS interactive deaggregation for a 2,475 -year return period indicates the seismic hazard at the site is dominated by the CSZ. The principal seismic sources comprising at least 5% of the overall hazard are summarized in Table 4D. Crustal earthquakes were included in the studies; however, the crustal earthquakes are not listed in Table 4D because each of the individual crustal sources represent less than 5% of the overall hazard at the site. Table 4D. Principal Seismic Sources based on USGS (2014) Seismic Hazard Maps Source Mean Moment Magnitude, W Mean Source -to -Site Distance, R (km) Percent Contribution CSZ Megathrust Interface 9.10 74.5 ±41.3 CSZ Megathrust Interface 8.92 125.0 ±18.2 CSZ Megathrust Interface 8.83 137.2 ±4.7 CSZ Megathrust Interface 8.73 74.1 ±3.9 South Hills 3rd Level Reservoir Replacement November 23, 2021 Seismic Hazard Study 11 Project No.: 2211098 Springfield, Oregon Springfield Utility Board The earthquake magnitudes and source -to -site distances used to generate the 2014 USGS maps satisfy the requirements of OSSC 2019. Seismic design parameters are discussed in the Site Response Spectra section of the main report. AWWA D100-11 design response spectra are shown on Figures 7A and 8A (Appendix A). CONCLUSION Based on the findings presented herein, it is our opinion there are no geologic or seismic hazards that would preclude the design and construction of the proposed reservoirs. This site-specific seismic hazard investigation for the South Hills 3rd Level Reservoir Replacement, Springfield, Oregon, was prepared by Brooke Running, R.G., C.E.G. G(�1tTiF/F� or�ooN 9NWI�KNUWIVIG /l ~ AMG GE�� e !pivW : Lj1/gL South Hills 3rd Level Reservoir Replacement November 23, 2021 Seismic Hazard Study 12 Proiect No.: 2211098 Springfield, Oregon Springfield Utility Board REFERENCES Adams, J., 1990, Paleoseismicity of the Cascadia Subduction Zone: Evidence from Turbidites Off the Oregon -Washington Margin: Tectonics, vol. 9, no. 4, p. 569 583, Atwater, B. F., Carson, B., Griggs, G. B., Johnson, H. P., and Salmi, M. S., 2014, Rethinking Turbidite Paleosetsmology Along the Cascadia Subduction Zone: Geology, published online 29 July 2014, doi: 10.11301G35902.1. Atwater, B. F., Nelson, A. R., Clague, J. J., Carver, G. A., Yamaguchi, D. K., Bobrowsky, P. T., Bourgeois, J., Darienzo, M. E., Grant, W. C., Hemphill -Haley, E., Kelsey, H. M., Jacoby, G. C., Nishenko, S. P., Palmer, S. P., Peterson, C. D., and Reinhart, M. A., 1995, Summary of Coastal Geologic Evidence for Past Great Earthquakes at the Cascadia Subduction Zone: Earthquake Spectra, vol. 11, no. 1, p. 1-18. Atwater, T., 1970, Implications of Plate Tectonics for the Cenozoic Tectonic Evolution of Western North America: Geological Society of America (GSA), Bulletin 81, p. 3513-3536. Barnett, E. A., Weaver, C. S., Meagher, K. L., Haugerud, R. A., Wang, Z., Madin, I. P., Yang, Y., Wells, R. E., Blakely, R. J., Ballantyne, D. B., and Darienzo, M., 2009, Earthquake Hazards and Lifelines in the Interstate 5 Urban Corridor: Cottage Grove to Woodburn, Oregon: US Geologic Survey (USGS), Scientific Investigations Map 3028, 1 Plate. Bela, J. L., 1979, Geologic Hazards of Eastern Benton County, Oregon: Oregon Department of Geology and Mineral Industries (DOGAMI), Bulletin 98, 122 p. Black, G. L., Wang, Z., Wiley, T. J., Wang, Y., and Keefer, D. K., 2000, Relative Earthquake Hazard Map of the Eugene -Springfield Metropolitan Area, Lane County, Oregon: Oregon Department of Geology and Mineral Industries (DOGAMI), IMS -14, 16 p. Bott, J. D. J., and Wong, I. G., 1993, Historical Earthquakes In and Around Portland, Oregon: Oregon Geology, vol. 55, no. 5, p. 116-122. Burns, W. J., Hofmeister, R. J., and Wang, Y., 2008, Geologic Hazards, Earthquake and Landslide Hazard Maps, and Future Earthquake Damage Estimates for Six Counties in the Mid/Southern Willamette valley; Including Yarr iD, Marion, Polk, Benton, Linn, and Lane Counties, and the City of Albany, Oregon: Oregon Department of Geology and Mineral Industries (DOGAMI), IMS -24, 50 p. Calhoun, N. C., Burns, W. J., Franczyk, J. J., and Monteverde, G., 2018, Landslide Hazard and Risk Study of Eugene -Springfield and Lane County, Oregon: Oregon Department of Geology and Mineral Industries (DOGAMI), Interpretive Map 60, 42 p., 1 Plate, Scale= 1:34,000. South Hills Set Level Reservoir Replacement November 23, 2021 Seismic Hazard Study 13 Protect No.: 2211096 Springfield, Oregon Springfield Utility Board DeMets, C., Gordon, R. G., and Argus, D. F., 2010, Geologically Current Plate Motions: Geophysical Journal International, vol. 181, no. 1, p. 1-80. Dewey, J. W., Hopper, M. G., Wald, D. J., Quitoriano, V., and Adams, E. 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B., 2006, Preliminary Geologic Map of the Eugene East and Eugene West 7.5' Quadrangles, Lane County, Oregon: Oregon Department of Geology and Mineral Industries (DOGAMI), OFR 0-03-11, 20 p. McClaughry, J. D., Wiley, T. J., Ferns, M. L., and Marlin, I. P., 2010, Digital Geologic Map of the Southern Willamette Valley, Benton, Lane, Linn, Marion, and Polk Counties, Oregon: Oregon Department of Geology and Mineral Industries (DOGAMI), 0-10-03, Scale: 1:63,360, 116 p. Nelson, A. R., Atwater, B. F., Bobrowsky, P. T., Bradley, L. -A., Claque, J. J., Carver, G. A., Darienzo, M. E., Grant, W. C., Drueger, H. W., Sparks, R., Stafford, T. W., Jr., and Stulver, M., 1995, Radiocarbon Evidence for Extensive Plate -boundary Rupture About 300 Years Ago at the Cascadia Subduction Zone: Letters to Nature, vol. 378, no. 23, p. 372-374. Noson, L. L., Oamar, A., and Thorsen, G. W., 1988, Washington Earthquake Hazards: Washington Department of Natural Resources (WADNR), Division of Geology and Earth Resources, Olympia, Washington, 77 p. O'Connor, J., Sarna-Wojcicki, A., Wozniak, K. C., Polette, D. J., and Fleck, R. J., 2001, Origin, Extent, and Thickness of Quaternary Geologic Units in the Willamette Valley, Oregon: U.S. Geological Survey (USGS), Professional Paper 1620, 52 p. Orr, E. L., and Orr, W. N., 1999, Geology of Oregon, Kendall/Hunt Publishing Company, Fifth Edition, 254 p. OSSC, 2019, Oregon Structural Speciality Code (OSSC): Based on the International Code Council, Inc., 2018 International Building Code (IBC), Sections 1613 and 1803. OSSPAC, 2013, The Oregon Resilience Plan - Cascadia: Oregon's Greatest Natural Threat: Oregon Seismic Safety Policy Advisory Commission (OSSPAC), February 2013. Palmer, A. R., 1983, The Decade of North American Geology - 1983 Geologic Time Scale: Geology, vol. 11, p. 503-504, September 1983. Personius, S. F., Dart, R. L., Bradley, L. -A., and Haller, K. M., 2003, Map and Data for Quaternary Faults and Folds in Oregon: U.S. Geological Survey (USGS), Open -File Report 03-095, v.1.1, Scale: 1:750,000, 507 p. Personius, S. F., and Nelson, A. R., 2006, Fault Number 781, Cascadia Megathrust, in Quaternary Fault and Fold Database of the United States: U.S. Geological Survey (USGS), website: https://earthquakes.usgs.gov/hazards/gfaults. South Hills 3rd Level Reservoir Replacement November 23, 2021 Seismic Hazard Study 1b Project No.: 2211098 Springfield, Oregon Springfield Utility Hoard Petersen, M. D., Moschetti, M. P., Powers, P. M., Mueller, C. S., Haller, K. M., Frankel, A. D., Zang, Y., Rezaeian, S., Harmsen, S. C., Boyd, O. S., Field, N., Chen, R., Rukstales, K. S., Luco, N., Wheeler, R. L., Williams, R. A., and Olsen, A. H., 2014, Documentation for the 2014 Update of the United States National Seismic Hazard Maps: U. S. Geological Survey (USGS), Open -File Report 2014-1091, 243 p., website: https://pubs.usgs.gov/of/2014/1091/. Peterson, C. D., Darienzo, M. E., Burns, S. F., and Burris, W, K., 1993, Field Trip Guide to Cascadia Paleoseismic Evidence Along the Northern Oregon Coast: Evidence of Subduction Zone Seismicity in the Central Cascadia Margin: Oregon Geology, vol. 55, no. 5, p. 99-114. PNSN, 1993, Scotts Mills 1993 M5.6 Earthquake Interactive Map: University of Washington, Pacific Northwest Seismic Network (PNSN), www.pnsn.org, M =5.6, 19.6 km deep, 1993-03-25 13:34:35 (UTC), Latitude: 45.035 N, Longitude: -122.607 W., posted by US Geological Survey (USGS), earthquake.usgs.gov/earthquakes/eventpage/UW1O3O6313/executive, accessed September 2020. 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K., and Wang, Z., 1998, Seismic Hazard Mapping in Eugene -Springfield, Oregon: Oregon Geology, vol. 60, no. 2, p. 31-41. Weaver, C. S., and Shedlock, K. M., 1996, Estimates of Seismic Source Regions from the Earthquake Distribution and Regional Tectonics in the Pacific Northwest: in Roger, A. M., Walsh, T. J., Kockelman, W. J., and Priest, G. R., eds., Assessing Earthquake Hazards and Reducing Risk in the Pacific Northwest, U.S. Geological Survey (USGS), Professional Paper 1560, vol. 1, p. 285-306. Wiley, T. J., 2008, Preliminary Geologic Maps of the Corvallis, Wren, and Marys Peak 7.5' Quadrangles, Benton, Lincoln and Linn Counties, Oregon: Oregon Department of Geology and Mineral Industries (DOGAMI), Open -File Report 0-08-14, Scale: 1:24,000, 11 p. Wong, I. G., and Butt, J. D. J., 1995, A Look Back at Oregon's Earthquake History, 1841-1994: Oregon Geology, vol. 57, no. 6, p. 125-139. Wong, I. G., and Silva, W. J., 1998, Earthquake Ground Shaking Hazards in the Portland and Seattle Metropolitan Areas: in Dakoulas, P., Yegian, M., and Holtz, R. D., eds., Geotechnical Earthquake Engineering and Sail Dynamics Ill, American Society of Civil Engineers (ASCE), Geotechnical Special Publication vol. 1, no. 75, p. 66-78. South Hills 3rd Level Reservoir Replacement November 23, 2021 Seismic Hazard Study 17 Project No.: 2211098 Springfield, Oregon Springfield Utility Board Yeats, R. S., Graven, E. P., Werner, K. S., Goldfinger, C., and Popowski, T. A., 1996, Tectonics of the Willamette Valley, Oregon: in Roger, A. M., Walsh, T. J., Kockelman, W. J., and Priest, G. R., ads., Assessing Earthquake Hazards and Reducing Risk in the Pacific Northwest; Volume 1, U.S. Geological Survey (USGS), Professional Paper 1560, Document and Plates 1 to 3, p. 183-222. South Hills Sid Level Reservoir Replacement November 23, 2021 Seismic Hazard Study 18 Project No.: 2211098 Springfield, Oregon Springfield Utility Board ulsoll reiTall — sewn r „9 Nm Wy l l ���� mow,m 2 •� Newprtt edam f COrvelli5,'y Albanymnrc,whase N,�ame,:;' .,a Lebanon 1 !pap Set, , M{ <SM Wvne 6Y .4rnX.m D.tY. I a. Eugene SITE t00' }may f I 5U. Fkea¢e1 1 a� am ti w pip fcas}emw. W /' Pars 0 Xppp )pt 13 copperp H VVW. Are1 9�� pv ¢I p. NOTES: 1. PORTION OF MAP BASED ON MAP OF QUATERNARY FAULTS AND FOLDS IN OREGON FERSONIUS ET AL., 2003). 2. SEE SITE-SPECIFIC SEISMIC HAZARD STUDY FOR A DISCUSSION OF LOCAL FAULTING. 3. FAULTS: 9719 = SALEM-EOLA HILLS HOMOCLINE; #862 = UNNAMED FAULTS NEAR SUTHERLIN; #863 = UPPER WILLAMETTE RIVER; 4869 = CORVALLIS; #870 = OWL CREEK; #1809 = WHITE BRANCH FAULT ZONE. 4. MAP IS NOT TO SCALE. MAP LEGEND: — Nmol'ena l<1o,DDoyearal«aoeuav glatletlon l<ls ocg r,aral-, nohlsbnc vii 13,000 3 In Gregor 10eale — LID.. matarytu1d0.0DDrears pcet perultlmele glaolallml — Late and mleme DaelemarY (a50 US raanl — groura lµ undmarenualae (<,,pba.coo rear) —fa aawnurt (age«odgm Uncertain) SLIP RATE TRACE al�e5mmseer Mosey rent—us at map anile —100 mu --- Metal dlewntruoua at map Selo 05lrear 0-10 aul --- I. -a or coreoul,l' — <o.mnuyea STRUCTURE TYPEy RELATED FEAT1IEs I Normal or nigh- aril, reverse fault Shop -slip Fault FrrmraW —{— MOcllnel bid �— Syrollrel fad —I— MmoonnaRad j Faull sectlar metkm irl egress / Plenary trilateral sped Primanent liver of stream I ntelmltlent deer or dream arR Pelmenent or rearn Thus lark, DETNLED STUDY Sl LES �­, Trani elle all Super. Ione ewer alt aW Foundation Engineering, Inc. QUARTERNARY CRUSTAL FAULT MAP FIGURE NO. 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