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ors City of Renton Stonegate II Lift Station Facility Evaluation November 2008 •� 4 04 L{ I I ti ti� , lei �, � . �• RENTON AHRAV 01' TFIK C:URVI Stonegate II Facility Evaluation Report November 2008 Prepared By Roth Hill Engineering Partners, LLC 2600 116th Avenue NE #100 Bellevue, WA 98004 (425) 869-9448 CERTIFICATION This Stonegate II Facility Evaluation Report for the City of Renton was prepared by Roth Hill Engineering Partners, LLC, under the direction of the following licensed professional engineers: Erik Brodahl, PE I �- O I` 1 1� .ter \ 3808 i O �; G13T f �\�w L R E N T O N Stonegate II Facility Evaluation TABLE OF CONTENTS Page No. EXECUTIVESUMMARY........................................................................................................1 Preferred Alternative Description and Estimated Project Cost/Schedule.................................1 Permitting/Critical Areas...........................................................................................................2 PROJECT PURPOSE............................................................................................................. 3 BACKGROUND....................................................................................................................... 3 SITEEVALUATION ...................................... :.......................................................................... 3 EXISTING FACILITY TOUR................................................................................................... 4 DESIGN CONSIDERATIONS...................................................................:.............................6 PUMP SIZING AND SELECTION........................................................................................... 7 WET WELL SIZING................................................................................................................. 8 BUILDINGS AND STRUCTURES.......................................................................................... 8 BuildingCode Review..............................................................................................................8 Architectural Considerations....................................................................................................9 Structural Considerations.........................................................................................................9 Building Mechanical: HVAC, Plumbing, and Fire Protection..................................................10 ELECTRICAL SERVICE.......................................................................................................12 Alternative1...........................................................................................................................12 Alternative2...........................................................................................................................12 StandbyPower.......................................................................................................................13 ControlSystem ............................... :.......................................................................................13 DETERMINATION OF PERMIT REQUIREMENTS AND TIMEFRAMES ...........................13 Required Project Permits.......................................................................................................13 Cityof Renton Permits...........................................................................................................14 STATE ENVIRONMENTAL POLICY ACT............................................................................14 CRITICAL AREAS AND REGULATORY REQUIREMENTS...............................................15 Wetlands................................................................................................................................15 Streams..................................................................................................................................15 GEOTECHNICAL EVALUATION..........................................................................................16 OPINION OF PROBABLE CONSTRUCTION COST(OPCC).............................................16 LIST OF TABLES Table 1 Seismic Load Design Requirements and Criteria......................................................10 Table 2 HVAC Design Conditions..........................................................................................11 Table 3 Opinion of Probable Construction Cost.....................................................................17 APPENDICES Appendix A - Site Layouts Appendix B — Pump Performance and System Curves Appendix C - Opinion of Probable Construction Costs Appendix D - Critical Areas Report (ESA Adolfson) Appendix E - Final Getechnical Report (HWA GeoSciences) Appendix F - Preliminary Building Code Review (Kennedy/Jenks Consultants) Appendix G - Preliminary Structural Evaluation (Kennedy/Jenks Consultants) RothHill ' RENTON Stonegate II Facility Evaluation Fj EXECUTIVE SUMMARY The City of Renton (City) authorized a Facility Evaluation as part of the design contract to analyze the replacement of the Stonegate Lift Station. The Stonegate Lift Station was constructed in 1996 and is undersized for the current projected upstream growth. This Facility Evaluation expands upon information provided in the Stonegate lI Alternatives Analysis Report completed in November of 2007. Within this evaluation, Roth Hill Engineering Partners, LLC (Roth Hill) prepared information on the station design, permitting issues, and cost estimate, while Kennedy/Jenks provided information on structural, architectural, HVAC, and electrical portions of the evaluation. A.geotechnical evaluation was also performed for the site by HWA GeoSciences, in addition to a critical areas report completed by ESA Adolfson. The study is comprised of several components, including a concept and constructability review, review of sizing calculations, determination of sensitive areas and permitting requirements, determining easement constraints and requirements, utility relocation requirements, and a cost estimate. An overview of the study, including a description of the preferred alternative for improvements, is summarized within this executive summary. ' Preferred Alternative Description and Estimated Project Cost/Schedule The proposed lift station will be constructed on a new easement within Tract "H" of the ' Stonegate subdivision, to the north of the existing station. The site is proposed to be situated to the north of the lawn in the tract, and south of an adjacent 100-foot wetland ' buffer. The site will be accessed from the east by a driveway connecting to 148`h Avenue SE. City staff has led the discussions with the Stonegate Homeowners' Association relating to the new location, and the Association has provided input and ' been receptive to the preferred alternative. The site will include a short block wall and landscaping to screen the station from neighboring residences. The site will also be fenced to deter vandalism. ' The preferred alternative features a single rectangular structure containing the combined wet well and one -hour of emergency overflow storage. The station will have ' two main submersible sewage pumps with 70 HP motors. Each pump will be capable of delivering approximately 425 gallons per minute (gpm) with the selected impellers, which should be adequate to handle the peak sewage inflow rates for the station under the interim build -out scenario within the current Urban Growth Boundary (UGB). With an impeller upgrade, these pumps and motors should be adequate'to handle the peak sewage inflow rates for the station under the ultimate design flow rate of 775 gpm. There will also be a smaller submersible sewage pump used to transfer sewage from the ' overflow storage area to the wet well. The pumps will discharge to a valve vault east of the station, where piping will be manifolded into a single force main. ' The control building will be a small CMU building housing all of the controls for the facility. The building is proposed to be a CMU building with a metal roof, with a color ' scheme to blend aesthetically with the neighborhood. The electrical controls will be RothHiII 1 ' RENTON Stonegate II Facility Evaluation very similar to and compatible with the City's most recently constructed lift stations. ' The site will also contain an 80 kW emergency generator, which will be located in a sound -attenuated enclosure outside of the control building, with a screening wall between the generator and the adjoining house to the north. The generator will be ' installed on a concrete pad with a 150-gallon sub -base fuel tank that will provide 24 hours of fuel storage at full -load. ' The estimated construction cost for this preferred option is approximately $1,569,000 including a 15% contingency and 9.0% sales tax. Design is anticipated to be completed in April of 2009, with construction beginning in the Summer of 2009, lasting from nine months to one year. Permitting/Critical Areas The necessary permits for the project include City of Renton Right -of -Way, Clearing and Grading, and Building permits. Fire Marshal approval will also be required. The building permit component is expected to involve the longest time frame (up to three months). A State Environmental Policy Act (SEPA) checklist and determination of non -significance will also need to be prepared, although it is not anticipated to have an impact to the overall schedule. The Critical Areas in the vicinity of the project include a wetland buffer and a stream. ' These areas lie outside of the proposed project site and should not adversely impact the project. The topics addressed above are described in more detail in this report. RothH111 2 ' R E N T O N Stonegate II Facility Evaluation PROJECT PURPOSE ' The City hired Roth Hill to complete this facility evaluation report to research and study the options and other considerations specifically associated with the replacement of the Stonegate Lift Station, located at the intersection of 148`h Avenue SE and NE 261h Street. The scope for the project includes evaluating up to three sites with regard to acquisition and siting issues, permitting issues, and construction requirements ' including geotechnical evaluation; electrical; structural; station sizing; pump and motor selection, access needs for future maintenance, impacts to the surrounding community and sensitive area, and a 30% Opinion of Probable Construction Cost (OPCC) and other potential cost impacts. BACKGROUND The City of Renton currently operates sanitary sewer collection and conveyance systems within its Upper May Creek/Honey Creek Subbasins in the northeast portion of ' the City, bordered by 148`h Avenue SE to the east and May Valley Road to the north. These systems include two sewage lift stations that serve a large portion of the area. The Summerwind Lift Station serves approximately half of the Summerwind development, and the existing Stonegate Lift Station serves several developments along the 148`h Avenue SE corridor. The existing Stonegate Lift Station was constructed in 1996 to serve the Stonegate subdivision. Since that time, further development has ' increased the amount of sewage that the lift station receives. The Stonegate Lift Station currently pumps to the Summerwind Lift Station, which in turn pumps to a ' gravity system in Duvall Avenue. As part of the project, the Summerwind Lift Station will be removed from service, with sewage rerouted by gravity to the Stonegate II Lift Station. The Stonegate II Lift Station will pump through a new force main to a gravity ' system in Field Avenue, which will alleviate projected capacity problems within Duvall Avenue. The original Stonegate Lift Station was designed with two, 20 HP pumps, each with a ' pumping capacity of 140 gpm against a Total Dynamic Head (TDH) of 125 feet. A recent Alternatives Analysis Report prepared by Roth Hill determined that 425 gpm of ' pumping capacity at a TDH of 150 feet is necessary for the current planning area and the pumping capacity would need to increase to approximately 775 gpm at a TDH of 180 feet for projected ultimate buildout conditions (outside of the current UGB). Given ' the projected peak flow rates to this station and the limitations of expanding the existing facility, it was decided that the construction of the Stonegate II Lift Station will be necessary. SITE EVALUATION The initial project scope identified the evaluation of up to three alternative locations for the proposed lift station. These locations were assumed to include: Rob H 111 3 RENTON Stonegate II Facility Evaluation 1 • Constructing the new. station on an expansion of the existing easement (within Tract "H" of the Stonegate developmenf) • Constructing the new station within the existing right-of-way to the east of Tract H • Constructing the station on another nearby parcel Constructing the new station on an expansion of the existing easement was considered the preferred alternative if the easement could be acquired by the City and if the station was environmentally feasible. This alternative was preferred due to the proximity of the easement to the existing station and infrastructure, the size of the available site, and this alternative would eliminate the City having to purchase land from adjacent homeowners potentially outside of the City limits, or installing less accessible underground facilities within the right-of-way. Talks with the Stonegate Homeowners Association have been positive and the easement required for the station appears to be obtainable by the City. In the event that the City is unable to obtain the required easement, the alternative site locations would need to be revisited. Preliminary site layouts show that the station can be constructed outside of the existing wetland buffer, therefore reducing environmental concerns. A more detailed description of the environmental issues is provided in the Determination of Permit Requirements and Timeframes section of this report. Since the preferred alternative appears to be feasible, the other two options were not considered in further detail. ' EXISTING FACILITY TOUR Roth Hill and Kennedy/Jenks staff met personnel from the City of Renton on April 17, 2008 to conduct a facility tour and to gather input relating to positive and negative attributes of existing stations within the City. The tour started with the Wedgewood Lift Station and then progressed to the Shy Creek, East Valley, and Stonegate Lift Stations within the City. The group also toured the Well 5B Facility in the City of Auburn designed by Kennedy/Jenks, and Lift Station 1013 and Lift Station 45 in Soos Creek Water & Sewer District, which were designed by Roth Hill. Some of the items noted by the City during the tour included: • The crew wanted a good slope to the overflow storage floor and a sump to aid with cleaning. Additionally, they want filleted corners if the station is rectangular, to assist with cleaning. • The City is interested in exploring different interior coating systems for the station. • For level sensors, the City prefers KPSI Sensors in a stilling well. RothHill 4 R E N T O N Stonegate II Facility Evaluation .t 11 FTII IIF T11F t:U Pt'F'. • Flow meters should be Siemens with read outs in the Control Room and via telemetry. • For telemetry, a panel should be built for the site, and the City will supply the unit. • The City would also like two or three pumps in the primary well with a manual start for the third pump (if needed). • Variable speed drives will not be used. • The City wants a fixed receptacle with a manual transfer switch in case a portable generator needs to be used on -site, in addition to an automatic transfer switch for the permanent generator set. • For access into the station, the City wants LW Products hatches. One question ' posed by the crew was if LW Products could provide bigger springs in the access lids to help with opening and closing the lids. • The City wants FRP ladders and grating systems and a retractable FRP ladder for the wet well similar to the Shy Creek station. • Other desired features include a platform at the top of the ladder, a handle welded onto the lid to aid entry accessing the ladder, and a safety net that can be placed over the station opening. '0 For the site, they liked the size of the control panel building at Shy Creek and want to make sure the building has gutters over the doors. Having the control ' panels covered is an important feature. • The City would like to see larger Hot Boxes over the water services and would ' like these boxes adjacent to buildings or at least out of the open area. • The crew would like to have photocell lights with the option to manually turn ' the lights off and on. • Wherever possible, the City would like pervious surfaces, such as pervious ' asphalt or concrete, used onsite. • The crew also mentioned that they like the idea of a fenced site in order to deter ' graffiti and vandalism. • The City staff was not comfortable with the concept of a generator set within the building, after visiting the Auburn Well 5B facility. • The City determined that a restroom will not be needed at this facility. RothH111 5 ' RENTON Stonegate II Facility Evaluation !1 In general, the City concluded that they liked the layout of the Shy Creek Lift Station the most of their existing stations, citing the ease of accessing equipment and cleaning the overflow storage area. The City wants the Stonegate II Lift Station to be designed with similar features to the Shy Creek Lift Station. DESIGN CONSIDERATIONS The site lies north of the existing Stonegate Lift Station site in a low area covered with tall grasses and blackberries in Tract "H" of the Stonegate subdivision, as shown in Appendix A. The proposed site is surrounded by a lawn -covered portion of the Tract to the south, 148`h Avenue SE to the east, a private residence to the west, and a 100- foot wetland buffer to the north. Special consideration is being given to the appearance of the station to blend in well with nearby residences. Consideration is also being given to the appearance from 148 `h Avenue SE and odor and noise produced by the station. Controlling noise at the site will be simple with an external generator set within a sound -attenuated enclosure. The site is being designed to facilitate easy access by maintenance personnel. Structures onsite will consist of the wet well and overflow storage, a valve vault, a control building with a screening wall for the generator set, and a transformer. Three different potential layouts for the wet well and overflow storage facility were developed for this study, including a rectangular station with the wet well inside of the overflow storage; a rectangular wet well separate from the overflow storage; and a circular station with an internal wet well. For the purposes of this report, the rectangular station with the internal wet well was chosen, as the preferred station configuration, because it is the most efficient use of the limited available space on -site. Additionally, this option was chosen due to the relative ease of constructing a rectangular station. The different layout options are provided in Appendix A. The existing station will be abandoned and the existing wet well channeled into a new gravity sewer manhole to connect the old and new stations. This gravity sewer will connect to a manhole on -site and then enter the new station through the south wall. In the preferred option, the internal dimensions of the station, including the wet well and overflow storage, would be approximately 30 feet long by 20 feet wide by 20 feet deep. The overflow storage will be designed for one hour of emergency storage at the maximum projected flow rate of 775 gpm for a required total volume of 46,500 gallons, or 6,220 cubic feet (CF). One hour of overflow storage is proposed due to the size of the facility that would be required to accommodate flows produced for two-hour storage and because of the extra capacity that is built into the system. Also, the permanent generator set and automatic transfer switch will reduce the likelihood of overflows. At the anticipated finished floor elevation of the overflow storage facility, the structure would have to be approximately 40 feet long by 30 feet wide by 20 feet deep (internal dimensions) to hold the two-hour storage volume. To determine the approximate quantity of excess storage provided in the one -hour storage facility, the difference between the invert of the gravity pipe and the ceiling of 1 RothHill 6 ' RENTON Stonegate II Facility Evaluation the proposed storage facility was used. With the assumption that sewage at the level of the ceiling in the proposed storage facility would not impact any upstream customers, approximately 45,800 gallons, or 6,125 CF of additional storage would be provided (including the existing wet well, but not any storage in the upstream gravity pipe and manholes), or approximately one hour of additional storage at a peak flow rate of 775 gpm. The ceiling of the proposed storage facility will be lower than the top of the two- hour storage in the existing wet well. ' A submersible pump will be sized to empty the overflow storage area back into the wet well. In order to help facilitate maintenance within the station, all walls shall be ' chamfered in the corners. Additionally, the floor of the overflow storage will be sloped towards the sump pump. ' The pumps will discharge from the wet well to the valve vault, which will be located to the east of the wet well/storage facility. The wet well sizing methodology is provided in the section "Wet Well Sizing." The valve vault is anticipated to be approximately 9 ' feet wide by 10 feet long and will manifold the discharge pipes into a single force main leaving the site to the east. ' The control building will be placed at the back of the site with double doors facing the east. A CMU wall will be constructed to the north from the west wall of the building for visual screening and to direct noise from the generator away from adjacent ' residences. The site will be leveled and raised to an approximate elevation of 322 feet, to further ' reduce the likelihood of flooding and to bring the site to the elevation of 1481" Avenue SE to the east. This will require the construction of a short block wall along most of the south and west sides of the site. Access to the site will be provided by a driveway ' off of 148 "' Avenue SE. Access to the site will be controlled by chain link fencing around the perimeter and a swinging gate at the entrance. Inside of the site, pervious ' pavement (or similar) shall be placed to provide vehicular access to the wet well, valve vault, control building and generator. On the perimeter on all sides of the site except the north, mature landscaping will be placed to minimize the visual impact of the ' station. Within the site, a creeping ground cover will be used to minimize maintenance and avoid having to mow. grass PUMP SIZING AND SELECTION The lift station will be sized based upon two design flow rates and the respective Total Dynamic Heads (TDH), as determined by Roth Hill in the Stonegate II Alternatives Analysis Report, dated November 2007. The peak design flow rate for the interim build -out condition is 425 gpm and the ultimate build -out rate is 775 gpm, with TDHs of 150 feet and 180 feet, respectively. The performance and the pump and system ' curves for these configurations are provided in Appendix B. The TDH will be further refined from these preliminary numbers after the force main route is selected and after ' Ro` Hill 7 R E N T O N Stonegate II Facility Evaluation internal piping and fittings within the station and valve vault are determined as the ' design progresses. Roth Hill coordinated with Michael Dennett of Whitney Equipment Company, Inc., the local Flygt Pumps representative. Mr. Dennett recommended two different configurations to meet the two and three -pump alternatives. The first configuration would include three 35 HP motors with 195 mm impellers. The second configuration ' would include two 70 HP motors with 370 mm impellers.. Both configurations are near the Best Efficiency Point (BEP), so either configuration allows flexibility as the final TDH is determined later in the design. Mr. Dennett also stated that impellers can be ' trimmed and provided with the two -pump option and 70 HP motors to meet the interim build -out pumping rate of 425 gpm. Based on discussions with the City staff, the two - ' pump configuration is preferred. WET WELL SIZING ' The wet well would be sized differently for a two pump configuration versus a three - pump configuration. The three -pump configuration would require a wet well sized approximately 6 feet by 12 feet and a total depth of 8.5 feet from finished floor to the ' overflow. The two -pump configuration would require a wet well sized approximately 6 feet by 8 feet. The wet well sizing calculations were performed for both the two- and three -pump options. With three pumps and four cycles per pump per hour, a minimum ' cycle time of 5 minutes/cycle would be achieved. Using the ultimate flow rate of 775 gpm, the wet well is required to have a minimum of 130 CF of active storage. With ' two pumps and four cycles per pump per hour, a minimum cycle time of 7.5 minutes/ cycle would be achieved. Using the ultimate flow rate of 775 gpm, the wet well would be required to have a minimum active storage volume of 194 CF. The preliminary wet ' well design provides approximately 192 CF of active storage within a 4-foot vertical operational range for setting on/off floats, for the two -pump configuration. proposed BUILDINGS AND STRUCTURES Building Code Review A preliminary building code review has been performed for the proposed facility and is attached for reference. The preliminary building code review was performed using the following codes as applicable for the project location: • International Building Code (IBC), 2006 with the State of Washington 2007 Amendments • International Fire Code (IFC), 2006 with the State of Washington 2007 Amendments ' • International Plumbing Code (IPC), 2006 with the State of Washington 2007 Amendments RothHill 8 R E N T O N Stonegate II Facility Evaluation F • International Mechanical Code (IMC), 2006 with the State of Washington 2007 Amendments • National Electrical Code (NEC), 2005 • State of Washington Energy Code, 2007 • Washington Industrial Safety and Health Act (WISHA). Significant findings from the building code review are noted below: • The project site is in the City of Renton, and zoned as R-1, Residential. A conditional use permit may be required. • Construction is Type V-B for wood -frame or masonry construction, and will not require fire sprinklers. • Protected openings or fire -rated walls should not be required if structures are set back 10 feet from the property line. • Compliance with State of Washington Energy code will require the Control Building be insulated if electric heat is provided. Architectural Considerations ' The Control Building is a single story structure, approximately 200 square feet. The building will include space for electrical equipment. Adjacent to the Control Building, a standby diesel engine -generator set (genset) will be provided in a stand-alone sound attenuating enclosure with integral fuel tank. The genset will be installed on a concrete slab. Sample renderings of the site have been developed based on the preliminary site plan, and are included in Appendix A. Renderings were developed for two alternatives requested by the City: '0 Wood -framed Control Building to match the appearance of adjacent housing • Concrete masonry unit (CMU) Control Building similar to other City facilities. Structural Considerations ' The Control Building, Lift Station, Valve Vault, and other structures will be designed in accordance with the Building Code at a minimum. Foundations and retaining walls ' will be designed in accordance with the recommendations of the geotechnical investigation (in progress). Seismic load design requirements and criteria are summarized in the Table 1. Additional structural design requirements are included the ' Preliminary Structural Evaluation attached for reference. 9 RothHill R7ENTON ,, ,., r", ! 1,t:R,C Stonegate II Facility Evaluation Table ll Seismic Load Design Requirements and Criteria Description of Coefficient Occupancy Category Site Coefficient Short Period Design Coefficient Long Period Design Coefficient Seismic Design Category Overstrength and Ductility Coefficient, R Seismic Amplification Factor, Q Coefficient IV 1.50 1.50 or as noted for equipment Ss = 1.399 S, = 0.476 FA = 1.0 Fv = 1.5 5 for masonry, 6.5 for wood 2.5 for masonry, 3 for wood As shown in the attached renderings, the Control Building will consist of either entirely wood construction resembling adjacent housing or of 8-inch masonry shear wall structure with a metal roof diaphragm utilizing wood roof framing and wood trusses supported at the exterior walls. Walls will be supported by continuous wall footings unless otherwise recommended in a revised geotechnical investigation. The floor shall consist of a minimum 6-inch monolithic concrete slab set at approximately 320 feet. The Lift Station will be a cast -in -place, minimum 1-foot thick reinforced concrete structure consisting of an interior wet well. with a secondary overflow storage structure, similar to other City lift stations. The Valve Vault will be a precast reinforced concrete vault. The Lift Station and Valve Vault will be constructed with aluminum, H2O rated ' access hatches and will be provided with interior access ladders and platforms constructed of fiberglass reinforced plastic (FRP). ' As previously indicated, detailed structural design criteria are included in the Preliminary Structural Evaluation in Appendix G. ' Building Mechanical: HVAC, Plumbing, and Fire Protection HVAC The Control Building will be heated and ventilated to maintain appropriate room temperatures for electrical equipment. Table 2 lists minimum and maximum outdoor ' and indoor design temperature conditions for the Control Building to be used for ROthHlll 10 RENTON Stonegate II Facility Evaluation 1 ki 1 1 HVAC system design. The outdoor design temperatures are based on 2005 ASHRAE Fundamentals Handbook. Table 2 HVAC Design Conditions Minimum (°F) Maximum (T) Outdoors 23 85 .. .. Electrical Room 45 85 The Lift Station falls under the NFPA 820 classification of a wastewater pumping station wet well. In accordance with Table 4-2 of NFPA 820, the Lift Station is exposed to fire and explosion hazards resulting from the possible ignition of flammable gases and floating flammable liquids. Ventilation is required in these areas to minimize fire and explosion hazards. Providing no ventilation or ventilation at a rate of up to 12 air changes per hour (ACH) in the Lift Station would result in a NEC Area Electrical Classification of Class I, Division 1. Continuously ventilating the Lift Station at a rate of 12 ACH would reduce the NEC Area Electrical Classification to Class I, Division 2. At this point, it is not intended to provide continuous ventilation for the Lift Station, so the Class 1, Division I classification applies. The Valve Vault falls under the NFPA 820 classification of a below grade valve vault. In accordance with Table 4-2 of NFPA 820, the Valve Vault is also exposed to fire and explosion hazards resulting from the possible ignition of flammable gases and floating flammable liquids. Ventilation is required in these areas to minimize fire and explosion hazards. Providing no ventilation or ventilation at a rate of up to 6 ACH in the Valve Vault would result in a NEC Area Electrical Classification of Class I, Division 2. Continuously ventilating the Valve Vault at a rate of 6 ACH would reduce the NEC Area Electrical Classification to Unclassified. At this point, it is not intended to provide continuous ventilation for the Valve Vault, so the Class I, Division I1 classification applies. Plumbing A restroom will not be included at the facility. Potable water service will be provided to the facility for wash down water in the yard. Per the Washington Administrative Code (WAC) (246-290-490), a reduced pressure backflow preventer is required for premise isolation. In addition, any water which has the potential to come into contact with sewage must be supplied through the approved air- gap, including water used for wash down water. Therefore, wash down water will not be provided inside of the Lift Station. The Valve Vault will be provided with a sump and sump pump for flood protection, hard -piped back to the Lift Station. RothHill 11 ' R E N T O N .ut_n ov ruF; r.cxv r. Stonegate II Facility Evaluation Fire Protection Fire sprinklers and fire alarm are not required per the Fire Code. However, smoke detection is required by the Fire Marshall. In addition, a fire hydrant capable of a fire ' flow of 1,500 gallons per minute shall be located within 300 feet of the Control Building. ' ELECTRICAL SERVICE New 480 VAC, 3-phase, 4-wire power to the site will be required from Puget Sound ' Energy (PSE), the electric utility. Service sizing calculations were performed using preliminary equipment sizes for two alternatives with differing quantity and size of submersible pumps utilized in the Lift Station: Alternative 1 ' Alternative 1 includes the following loads for electrical service sizing: • Three 35 HP submersible pumps with solid-state soft starting ' • One 240/120-volt panel board fed by a 10 kVA dry -type indoor transformer. ' Based on the loads indicated above, a 100 kVA utility transformer would likely be installed by PSE. A 150 amp Service Entrance main circuit breaker would be installed in the Control Building. A CT enclosure and meter base will be mounted on the exterior of the building, suitably located for access by PSE. A 150 amp rated ' Automatic Transfer Switch (ATS) would be installed to automatically start the standby genset and switch the facility to standby power when utility power fails. A Motor Control Center (MCC) would be provided that includes the three solid state soft starters for the pumps, a 10 kVA transformer, and 240/120-volt panel board. Panel board circuits will provide power to the local control panel, building lighting and heating, and vault lighting. ' Alternative 2 Alternative 2 includes the : following loads for service sizing: ' • Two 70 HP submersible pumps with. solid-state soft starting tBased • One 240/120-volt panel board fed by a 10 kVA dry -type indoor transformer. on the loads indicated above, a 150 kVA utility transformer would likely be installed by PSE. A 200 amp Service Entrance main circuit breaker would be installed in the Control Building. Similar to Alternative 1, a CT enclosure and meter base will be mounted on the exterior of the building, suitably located for access by PSE. A 200 amp rated ATS will be installed to automatically start the standby generator and switch the ROthHlll 12 ' RENTON Stonegate II Facility Evaluation facility to standby power when utility power fails. An MCC will be installed that will ' include the two solid state soft starters for the pumps, a 10 kVA transformer, and 240/120-volt panel board. ' Panel board circuits will provide power to the local control panel, building lighting and heating, and vault lighting. ' Standby Power A standby genset will be provided at the facility provide backup power in case of loss of power. The genset will be sized to operate all pumps in each scenario above. As indicated above, the genset will be located in a standalone, sound attenuating enclosure installed on a sub -base diesel fuel tank sized for 24 hours of fuel storage at full load operation. WAC 173-60-050 exempts emergency equipment from the sound ordinance. Therefore, the genset enclosure will be sized to limit noise at the property line to the 45 dBA limit required by the City. Genset sizing calculations were performed using ' preliminary equipment sizes for the two alternatives described above: • Alternative 1 : 125 kW genset with 250-gallon sub -base fuel tank. '0 Alternative 2: 80 kW genset with 150-gallon sub -base fuel tank. ' Control System The City has standardized on the use of a Local Control Panel designed and programmed by Systems Interface Inc. The panel consists of a Rugid RTU with a LCD operator interface panel, and includes radio -based communications to the City's SCADA system. A Yagi antenna will be located on the site at the required height to ' establish reliable communications. DETERMINATION OF PERMIT REQUIREMENTS AND TIMEFRAMES ' Roth Hill has determined the necessary permits and estimated the corresponding time frames for the lift station replacement. The City of Renton will require right-of-way, ' grading, fire marshal approval, and building permits, all of which are obtained through a common submittal process. The building permit portion of the submittal will involve the longest timeframe. Additionally, a SEPA checklist and determination of non - significance will need to be completed as part of the project. Due to the proximity of Critical Areas to the project site, a Critical Areas Report has been completed, and the respective Critical Areas are addressed below. The permits and time frames are explained in more detail below. Required Project Permits The project permits required for this project are anticipated to be as follows: ' • City of Renton. Clearing and Grading Permit RothH111 13 ---------------------- RENTON Stonegate II Facility Evaluation • City of Renton Right -of -Way Permit • City of Renton Fire Marshal approval • City of Renton Building Permit City of Renton Permits The proposed site will require a Clearing and Grading permit since the excavation of the station will remove a significant amount of material. A Right-of-way permit will be required in order to construct the driveway for the station and piping improvements. Fire Marshal approval will be required for the. generator. These permits are typically obtained very quickly and would not be expected to be a significant issue with regard to the project timeline. The proposed site re -development will require a building permit from the City of Renton. The site is currently in use as a common area for the Stonegate Homeowner's Association and also houses the existing City -owned Stonegate Lift Station. The use of the site will not change; placement of the proposed lift station just north of the existing location, outside of the wetland buffer to the north, will greatly reduce permitting concerns. The City building permit may require a pre -application meeting at the 30% design stage. Upon completion of the 90% design, the final application can be submitted for review and approval. The length of this process typically takes approximately three months depending on the complexity of the building and selected location. Excavation and construction is only anticipated in the areas outside of any mapped critical areas and the associated wetland.buffer. The City of Renton requires a wetland delineation report and a geotechnical report to address the proposed building and its location. These reports have been prepared as part of this study. Because the plan is to install the lift station in the area of least impact, the proximity of sensitive areas may not be an over-riding concern. The City's critical areas ordinance may require more information about existing site conditions and possible project impacts. The City will also require a landscape/restoration plan. Per the project scope, Roth Hill will prepare the required permits and the City shall be responsible for all applicable permitting fees or bond requirements. STATE ENVIRONMENTAL POLICY ACT The City of Renton requires completion of a SEPA checklist as part of the permitting process for a building permit. The City of Renton will be the lead agency for SEPA on this project and will issue the determination based on the information provided in the checklist. The project is not expected to impact any City mapped critical areas and it is expected that the City will issue a Determination of Non -significance for this project. RothHiI1 14 ' R 1 (� T E N TO\'�. N Stonegate II Facility Evaluation .11..At' e CRITICAL AREAS AND REGULATORY REQUIREMENTS The project site lies entirely within the jurisdiction of the City of Renton. Permitting requirements are established by the City of Renton Municipal Code and administered ' by the City's Development Services Division. City of Renton maps indicate that the following critical areas are in the vicinity: ' Streams (flows north through the subdivision west of station site; tributary of May Creek) ' • Wetland buffer (associated with May Creek and tributaries on adjacent parcel to the north) ' Wetlands City of Renton maps indicate that there are no wetlands within the project site. There ' is a delineated wetland to the north of the project parcel and the 100-foot buffer for that wetland is adjacent to a small portion of the project site, north of the proposed lift station. The entire site is south and outside of the 100-foot buffer zone. The wetland was delineated and mapped by ESA Adolfson in the Stonegate II Lift Station and Pipeline Project Critical Areas Report (June 2008) and is included in Appendix D of this document. The site layout has been developed to specifically avoid the wetland buffer, which will simplify project permitting. if the construction limits of the proposed lift station change and encroach on the wetland buffer, the City of Renton could require a modified critical areas report to address any potential construction impacts. Identified effects could result in building permit conditions as well as mitigation requirements to ' compensate for those impacts. The City has already contracted with ESA Adolfson to conduct the necessary studies, delineation and report preparation. Having this information ahead of time will help to avoid any delays in the review and permitting process. The requirement for a critical areas report could arise at the permit pre -application phase, where the project will be ' discussed with the City of Renton Planners and officials. The report may have to be submitted with the permit applications from this project. ' Streams Streams may have.associated setbacks and restrictions, especially those with resident ' and migratory fish populations. The stream classifications dictate the required setbacks. ESA Adolfson has identified the presence of a May Creek tributary within the project parcel but not near the project site. The tributary runs through the western ' portion of the project parcel, while the proposed lift station will be located within the eastern portion of the property. The tributary is about 5 feet wide and 1 foot deep where it crosses NE 26th Street, and dominated by Sitka willow, red alder, reed canary RothHill 15 ' R E N T O N Stonegate II Facility Evaluation grass and Himalayan blackberry plants. A fish presence was not indicated. There are ' three developed residential parcels between the stream and the proposed lift station, which places the lift station project well outside of the required tributary buffer. GEOTECHNICAL EVALUATION A preliminary geotechnical report (Appendix E) has been prepared by HWA ' GeoSciences, including recommendations for the lift station site. Two borings were advanced slightly beyond 40 feet in the vicinity of the proposed facility.. The subsurface soils were determined to be generally suitable for support of the wet ' well/overflow storage structure. Groundwater was encountered at about 7.5 feet below the surface in both borings, and the report recommends assuming groundwater at the surface for design purposes. The report recommends an interlocking sheet pile system ' for shoring, with dewatering wells or a mud mat. The final version of the report will provide more detailed soil parameters and backfill recommendations. OPINION OF PROBABLE CONSTRUCTION COST (OPCC) The engineer's OPCC is provided in Table 3 and was prepared for the lift station ' replacement based on the preferred alternative which includes: • Using the site within Tract `H' to the north of the Stonegate Lift Station ' • Constructing an approximately 30-foot long by 20-foot wide combined overflow storage and wet well station ' • Using a two -pump submersible configuration with additional impellers ' • A valve vault • A control building with screening wall • An outside generator set in a sound -attenuated enclosure • Porous paving driveways and access within the site ' • Mature landscaping along the perimeter and creeping ground cover within the site ' • Chain link fencing ' • Extended sidewalk from NE 26th Street to the north edge of the driveway apron ' RothHiI1 16 R E N TO N Stonegate II Facility Evaluation Table 3 Opinion of Probable Construction Cost Subtotal of Construction Bid Items ........ ........... ......... .....- _ .... ._...... . _ Washington State Sales Tax @ 9.0% ......--$1,251,000 $113,000 Subtotal (Engineers Estimate) $1,364,000 Contingency @ 15% of Engineer's Estimate $205,000 Opinion Probable Construction Cost (OPCC) $1,569,000 ' A detailed construction cost estimate is included in Appendix C. A contingency of 15% and 9.0% sales tax were included with the construction costs for the estimate. ' Project costs will include engineering fees, easement acquisition, City costs or legal fees, geotechnical and survey services. These items are not included in the OPCC. ' Ro Hill 17 Appendix A RENTON Stonegate II Facility Evaluation IJ I 1 P Appendix A Site Layouts ' Rot Hill I'NN Nol "fA AL e PC ._,� K, . ►,: ' * -�\� o ��'s. fir' 4 ' �'!%%p ^-i ___ � - — •� -- p� ';� •� �+ 'r � s � ;'t- at � �_��.. - � 1' `f w 1,� �,v �i� tiS ��i � : • � f '. �., �., ' , .` \ � ' L � u OF 7 | / ' ,°* IN FEET w | KEYSTONE UV�| / | ../-.u.u/,�- ,,,.� /LANDSCAPING 7/ i | EX. WET WELL CON IR01 PROPOSED GRAVITY SEWER ' | } i � Ys |M' ^ ' LIFT STATION AURt IN | � / | / / -� ! | ! --- � �� /=-~ \/ ! � \ / ^ / \ `` ----------___-------------- / | -- -^ \ KEYSTONE WAL 11� Boni : on eggs vv c/R�,� - - \ PROPOSED A " FOR~E .A.|N ---�------� '-----_-l' -- / |l -^ � � �~�K� AVES.E. U����UUU������ ���- _-_-__-_--_-_-__-_------- ----_-_-___� U�U������U���� UU~U U �~n �Uv���� WET WELL 10 0 10 20 'rl SCALE IN FEET i ! If2111 i i 3���.52 �� 115 11a Eh 1,1 IE 5.412��N� nll ?v 1 \ 1 E I S i I-N G } I• ' a�, w S FMB j_ co i j. I\ 'I EXISTIN -- - -,-�-� VALVE/AULTW ?'R� \� •� _ _mod_ �d� i \ I \ I _Tl 6 LINE OF 7 SMALL FIR TREES ______________________J---_—_ _ KEYSTONE WALL / \ m Ex FORCE MAIN �s LANDSCAPING I\ ll s 322-- EX. WET WELL o \ m ! --- \i ELECTRICAL i % CONTROLS PROPOSED —i 1 c GRAVITY \\ �f m SEWER U / _ I c CHAIN LINK FENCE � � �� WELL oft kip - - � _ /� D o �` l 2'TALL LAUREL r �\ VALVE ■ ■Z. co VAULT J / . ■-_ '■ ' D KEYSTONE / L o r WALL ulI / / i ...... .....—.-J.................. 0 III \ / ■ \ - - - Co. --_' f` v \ .........1.ison I..\ ....... ..............■ \ O \ — —- --_—_-- DOUBLE YELLOW ST14 PE PROPOSED 8"'FORCE MAIN -=---------- r���-•-----------_` /---------------- -�/ - CONTROL / BUILDING /t GENERATOR i ONE —HOUR / OVERFLOW j / STO-RAGE / / Q,6'x25') NEW TRANSFOR-MEIle R -- -- / \ 148TH`AVE—S.E.-------- ' SEPARATE WET WELL I LINE OF 7 SMALL FIR TREES CD � SCALE IN FEET ------------- --------------- / KEYSTONE :; -- w WALL i / I CONTROL �w co LANDSCAPING BUILDINGol / EX. WET WELL 1 / GENERATOR / \i PROPOSEDcy) 1 o 41 GRAVITY { \\ C - SEWER 320- - wLL- j o i'LLJOD _S-T-A TI-O N-- i \(32' DIA.) j �/ ;o >2'TALL LAUREL � l /f !i J / NEW i z TRANSFORMER KEYSTONE / % CHAIN LINK r , WALL FENCErT Ten �\\:: .\ 1 \ r ❑ �.`. / / _ —,� ... / com ------------ - - - - - - - - - - - - - _ - _ ... ... .. ... ... _ N -- \ \, DOUBLE YELLOW STRIPE 148TH AVE S.E. PROPOSED 81'FORCE MAIN __ - - / , �% /, -- - - CIRCULAR r STATION Appendix B ' R E N T O N Stonegate II Facility Evaluation A 114'..�IL f44 TIIR 1: I: Yt'L'. Appendix B Pump Performance and System Curves C LI ' Rot Hill 2 C 1 FLYGT PERFORMANCE CURVE PRODUCT NP3202.090 TYPE HT DATE PROJ ECT CURVE NO ISSUE 2008-05-14 63-465-00-4060 1 1/1-LOAD 3/4-LOAD 112-LOAD RATED IMPELLER DIAMETER POWER..... 70 hp 370 mm POWER FACTOR 0.88 0.84 0.75 EFFICIENCY 92.5 % 93.0 % 92.5 % STARTING CURRENT ... 615 A MOTOR a STATOR REV MOTOR DATA — — — RATED CURRENT ... 80 A RATED 1775 30-29 4AA 01 10 COMMENTS INLET/OUTLET FREQ. PHASES VOLTAGE POLES 4 4 inch SPEED rpm TOT.MOM.OF 60 Hz 3 460 V 4 INERTIA ... 0.49 kgm2 IMP. THROUGHLET GEARTYPE RATIO NO. OF --- BLADES 2 --- --- [hp] 0 3 o a a 80 _ ~ u_ I _ a Z o w _ O 40 - LL w � a w a- O a- DUTY -POINT FLOWIuSgpml HEAD(fl] POWER [hp] EFF. [%J NPSHre(Rl GUARANTEE 0 k 1 798 181 65.2 (60.5) 56.3 (60.6) 13.8 B-E.P. 1113 155 59.2 (63.8) 14-5 HI level A INNPSHre z [h] LL J Lu w G w O 250 m a 2.5 ra EFF. Q1 70 = 150 P, — 7.5 60 \ \ I 50 100 5.0 40 30 50 - —12.5 20 - 10 0 0 0 200 400 600 800 1000 1200 1400 1600 1800 [U Sgpm] FLOW NPSHre = NPSH3% + min. operational margin GUARANTEE BETWEEN LIMITS (G) ACC- 70 Performance with dear water and ambient temp 40 °C H I level A J r PRODUCT L? 4i':r�NP3171.091 PERFORMANCE CURVE SH DATE PROJECT CURVE NO ISSUE 2008-05-14 63-275-00-1070 1 1/1-LOAD 314-LOAD 1/2-LOAD RATED IMPELLER DIAMETER POWER ..... 35 hp 195 mm POWER FACTOR 0.92 0.91 0.86 EFFICIENCY 90.5 % 91.5 % 92.0 % STARTING CCURRDENT ... 273 A STATOR REV MOTOR DATA — — — RATE CURRENT ... 39 A RATED SPEEDTOT.MOM.OF 3520 �MOTOR# 25-18-2AA 01 10 VOLTAGE COMMENTS INLET/OUTLET FREO. PHASES POLES / 4 inch rpm 60 Hz 3 46C V 2 INERTIA... 0.073 kgm2 IMP. THROUGHLET GEARTYPE RATIO NO. OF --- BLADES 2 --- I --- Lu w [hp] — — — — — — W I O O a s 35 I I a a 30 S, 1 O w 25 L O LL LL 20 w — -- J LL w a w � O a DUTY -POINT FLOWIuSgpm] HEAD(ti] POWER (hp) EFF.(%i NPSHrelnl GUARANTEE 0 1 375 176 33.2 (30.3) 50.3 (55.1) 14.9 B.E.P. 541 142 54.3 (59.7) 21.7 HI level A NPSHre IN Z [ft] a LL LL � W U) W 250 — — — 2.5 I- - I _ EFF. 200 - - - -- -- 50.0 [%] Q 1 w I 150 = 7.5 30 SH e=3 - - 100 — ?� 5.0 20 �G 50 —12.5 10 0 100 200 300 400 500 600 700 800 900 [USgpm] FLOW NPSHre = NPSH3% min. operational margin FGUARANTEE BETWEEN LIMITS (G) ACC. TO Performance wi(h clear water and ambient temp 40 °C H I level A 400 350 300 250 200 150 100 50 0 Two Pump Configuration Pump Curve w/ System Curve 1100 .............. . . . . .. ........... Flow (gpm) ® ® 1 Pump ......• 2 Pumps C=145 Three Pump Configuration Pump Curve w/ System Curve 400 350 ---------- 0010 300 250 11 00� 200 m I Pump ....... 150 2 Pumps - 3 Pumps 100 - C=145 50 0 eo Flow (gpm) Appendix C Stonegate II Facility Evaluation Appendix C Opinion of Probable Construction Costs 3 Rot Hill Roth Hill Engineering Partners, LLC 2600 - 116th Ave NE, #100 Bellevue, WA 98004 TITLE: Stonegate II Lift Station OPCC OWNER: City of Renton PROJECT: Stonegate II Lift Station JOB NO: 0015.00018.100 Bid Item Description Prepared by: LDS Date: 6/20/2008 Checked by: ELB Date: 7/1 /2008 30% Design All Costs in Year 2008 Dollars Approx. Quantity Unit Unit Cost Total Cost 1 Mobilization (Not to Exceed 8% of Contract Total) 1 LS $ 80,000.00 $ 80,000 ' 2 3 Temporary Erasion & Sedimentation Control Facilities Filter Fabric Fence 1 400 LS LF $ 20,000.00 $ 8.00 $ $ 20,000 3,200 4 Site Clearing and Grading 1 LS $ 15,000-00 $ 15,000 - 5 Temporary Shoring and Dewatering for Lift Station 1 LS $ 160,000.00 $ 160,000 6 Excavation and Backfill 1 LS $ 60,000.00 $ 60,000 7 30'x20' CIP Wet Well and Overflow Storage 1 LS $ 125,000.00 $ 125,000 ' 8 Precast Concrete Valve and Flow Meter Vault 1 LS $ 28,000.00 $ 28,000 9 Submersible Sewage Pumps and Motors 2 EA $ 45,000.00 $ 90,000 10 Submersible Sewage Transfer Pump and Motor 1 EA $ 8,000.00 $ 8,000 11 Lift Station Piping 1 LS $ 25,000.00 $ 25,000 12 Wet Well Accessories 1 LS $ 12,000.00 $ 12,000 13 Safety Grating 1 LS $ 20,000.00 $ 20,000 14 Wet Well / Overflow Storage Coatings 1 LS $ 45,000.00 $ 45,000 15 Valve Vault Coatings 1 LS $ 6,000.00 $ 6,000 16 Convert Existing Stonegate Wet Well to Gravity Manhole 1 LS $ 5,000.00 $ 5,000 17 CMU Control Building with Screening Wall 1 LS $ 84,000.00 $ 84,000 ' 18 Control Building Plumbing - Roof Drains I Footing Drains 1 LS $ 5,000.00 $ 5,000 19 Mechanical Work 1 LS $ 7,500.00 $ 7,500 20 Electrical Work 1 LS $ 80,000.00 $ 80,000 21 Instrument and Control System 1 LS $ 100,000.00 $ 100,000 22 Alarm/SCADA/Telemetry System 1 LS $ 20,000.00 $ 20,000 23 Testing and Startup Services 1 LS $ 12,500.00 $ 12,500 24 Standby Generator Set 1 EA $ 65,000.00 $ 65,000 25 12-Inch PVC Gravity Sewer Main 100 LF $ 150.00 $ 15,000 26 48" Dia, Manhole 1 EA $ 6,000.00 $ 6,000 27 48" Dia. Manhole, Over 10' 5 VF $ 200.00 $ 1,000 ' 28 Trench Shoring Systems 120 LF $ 60.00 $ 7,200 29 Ductile Iron Sewer Fittings 1000 LB $ 4.00 $ 4,000 30 Clay Dams 2 EA $ 1,500.00 $ 3,000 31 32 Heat Shrinkable Manhole Wrap 1-Inch Water Service w/ Backflow Preventor, Hot -Box, Yard Hydrant 1 1 EA EA $ 2,000.00 $ 4,000.00 $ $ 2,000 4,000 ' 34 Bank Run Gravel (As Required) 1200 TON $ 20.00 $ 24,000 35 Quarry Spalls (As Required) 75 TON $ 28.00 $ 2,100 36 Crushed Surfacing (As Required) 50 TON $ 28.00 $ 1,400 ' 37 38 Sidewalk Porous Pavement for Driveway and access 70 150 SY SY $ 50.00 $ 150.00 $ $ 3,500 22,500 39 Miscellaneous Concrete Work 1 LS $ 6,000.00 $ 6,000 40 Existing Stonegate Lift Station Abandonment 1 LS $ 10,000.00 $ 10,000 41 Existing Summerwind Lift Station Abandonment 1 LS $ 16,000.00 $ 16,000 ' 42 43 Chain Link Fence Landscaping and Surface Restoration 1 1 LS LS $ 15,000.00 $ 32,000.00 $ $ 15,000 32,000 Subtotal $ 1,251,000 Washington State Sales Tax @ 9.0% of subtotal $ 113,000 Subtotal ("Engineer's Estimate") $ 1,364,000 Contingency @ 15% of Engr's Est. $ 205,000 Total Probable Construction Cost $ 1,569,000 1 7/2/2008 Page 1 of 1 F:\0015\00018.001\DESIGN #28245\Costs\30% OPCC 070208.x1s Appendix D ' R E N T O N Stonegate II Facility Evaluation Appendix D Critical Areas Report (ESA Adolfson) IRot Hill 4 STONEGATE II LIFT STATION AND PIPELINE ' PROJECT Critical Areas Report 1 1 ' Prepared for: August 2008 City of Renton 1 I F� 1 1 1 Stonegate 11 Li%t Station and Pipeline Project Critical Areas SUMMARY At the request of Roth Hill Engineering Partners, LLC, ESA Adolfson delineated wetland boundaries, flagged the ordinary high water mark of streams, and prepared this technical report for the Stonegate II Lift Station and Pipeline Project, located in the City of Renton, Washington. The Stonegate Lift Station II and Pipeline Project includes the construction of a new lift station near the existing Stonegate lift station and construction of a new force main from the new Stonegate II lift station to the City's existing sewer system along Field Avenue NE. Due to easement constraints, the force main alignment has been recently revised. The project area is generally bounded by May Creek to the north, NE Sunset Boulevard to the south, and 148`h Avenue SE to the east. Single-family residential development is the predominant land use in the area. The field investigation found two wetlands and two streams located in the project area. Wetland A is located north of the proposed lift station. The wetland contains PEM/PSS communities and has a riverine and depressional HGM classification. Wetland A is considered a Category I wetland and has a required standard buffer of 100-feet (RMC 4-3-050 M6). The wetland continues offsite to the north and northwest. Wetland B is located in the southwestern portion of the project area near the intersection of SE 104`h Street and 147`h Avenue SE. Wetland B contains a PFO community and has a riverine HGM classification. It is considered a Category III wetland with a required standard buffer of 35-feet (RMC 4-3-050 M6). May Creek is located in the northern portion of the project area and travels through Wetland A. The stream is considered a Class 2 with 100 foot buffers. The tributary of May Creek enters the project area from the south, flowing under SE 104`h Street and then adjacent to Wetland B. The tributary continues north, traveling under NE 26`h Street and then drains to May Creek. The tributary of May Creek is considered a Class 4 that requires 35 foot buffers. To avoid impacts to aquatic resources located in the project area, the proposed lift station near NE 26`h Street and 1481h Avenue SE has been located outside the 100-foot buffer of Wetland A. Construction of the new force main along NE 261h Street may involve tunne I ing/direct tonal drill methods in the vicinity of the tributary, which would not require in -water work or cause impacts to the stream buffer. ESA Adolfson Page i ' August 2008 11 11 1 I 11 Stonegate 11 Lift Station and Pipeline Project Critical Areas Report CONTENTS 1.0 PROJECT AUTHORIZATION AND SCOPE OF WORK.......................................................1 2.0 PROJECT DESCRIPTION..........................................................................................................1 3.0 SITE DESCRIPTION....................................................................................................................1 4.0 WETLAND DEFINITION AND REGULATIONS....................................................................2 5.0 METHODS.....................................................................................................................................2 5.1 REVIEW OF EXISTING INFORMATION.....................................................................................................2 5.2 ON -SITE INVESTIGATION.......................................................................................................................3 5.2.1 Determining the Presence of Wetlands and Delineating Wetland Boundaries ..................... 3 5.2.2 Classifi,ing Wetlands............................................................................................................. 3 5.2.3 Assessment gfAyuaticAreas.................................................................................................3 6.0 FINDINGS......................................................................................................................................4 6.1 EXISTING INFORMATION.......................................................................................................................4 6.2 WETLANDS DETERMINATIONS..............................................................................................................4 6.2.1 Wetland A.............................................................................................................................. 5 6.2.2 Wetland B.............................................................................................................................. 5 6.3 STREAMS AND OTHER DRAINAGE FEATURES........................................................................................6 6.3.1 May Creek............................................................................................................................. 6 6.3.2 Tributary o/'May Creek......................................................................................................... 6 6.4 UPLAND DESCRIPTION..........................................................................................................................7 6.5 WILDLIFE..............................................................................................................................................8 7.0 REGULATORY IMPLICATIONS..............................................................................................8 7.1 FEDERAL REGULATIONS.......................................................................................................................8 7.2 STATE REGULATIONS............................................................................................................................9 7.3 LOCAL REGULATIONS...........................................................................................................................9 8.0 LIMITATIONS............................................................................................................................10 9.0 REFERENCES................................................................................................. >I >I 10.0 GLOSSARY..................................................................................................................................12 FIGURESAND PHOTOGRAPHS.........................................................................................................17 ESA Adolfson Page iii ' August 2008 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Stonegate Il Lift Station and Pipeline Project Critical Areas Report LIST OF APPENDICES Appendix A - Methods Used to Evaluate Wetland Characteristics Appendix A Appendix B - Common and Scientific Names of Plants and Their Wetland Indicator Status Appendix C - Wetland Determination Data Sheets LIST OF TABLES 1 Aquatic Resource Classification and Rating LIST OF FIGURES 1 Vicinity Map 2 Wetlands and Streams -Existing Information 3 Key Map 4 Wetlands and Streams -Lift Station 5 Wetlands and Streams -Force Main Page iv ESA Adolfson August 2008 Stonegate 11 Lift Station and Pipeline Project Critical Areas Report ' 1.0 PROJECT AUTHORIZATION AND SCOPE OF WORK At the request of Roth Hill Engineering Partners, LLC (client), ESA Adolfson delineated wetland ' boundaries, flagged the ordinary high water mark of streams, and prepared this technical report for the City of Renton Stonegate II Lift Station and Pipeline Project (the project), located in the ' City of Renton, Washington. The boundaries of the study area were established based on maps provided by Roth Hill Engineering Partners, LLC. The Scope of Work for this project included wetlands determinations, delineations, an assessment of wetland functions, and stream survey, all of which are summarized in this technical report. A brief analysis of potential wetlands impacts, and a discussion of regulatory implications and permitting considerations are also included in this report. The development of a mitigation plan was not included in this Scope of Work. ' 2.0 PROJECT DESCRIPTION The Stonegate II Lift Station and Pipeline Project includes the following components: • Construction of a new lift station near the existing Stonegate lift station. • Construction of a new force main between the new Stonegate Il lift station to the City's ' existing sewer system along Field Avenue NE. The force main alignment was recently revised due to easement constraints. ' • Demolish existing lift station and site restoration. 3.0 SITE DESCRIPTION 1 The project area is located in the northern portion of the City of Renton (Figure 1). The project ' area is generally bounded by May Creek to the north, NE Sunset Boulevard to the south, and 148`h Avenue SE to the east. The proposed force main alignment extends west on NE 26`h Street, then travels south along Lyons Avenue NE. The alignment turns southwest onto NE 22nd Court and continues west on NE 201h Street, turning southwest on Field Avenue NE until a tie-in to the existing City system. Figures 2 and 3 show the proposed lift station location and force main alignment. Single-family residential development is the predominant land use in the area. The wetland and stream investigation focused on the proposed lift station area and undeveloped g p p areas along the proposed force main alignment. The proposed lift station site is a 38,185 sq. ft. (0.88 acre) parcel (8035400580) located on the northwest corner of 148`h Avenue SE and NE 26`h Street. The parcel is relatively flat, sloping down gradually to the north toward May Creek. A break in topography occurs between un-maintained and landscaped portions of the parcel, located north of the existing lift station. An un-maintained parcel (803540TRCT) north of the existing lift station was also investigated. For purposes of the investigation, this area was ' bounded by May Creek, a tributary of May Creek, and 148`h Avenue SE. ESA Adolfson Page I ' August 2008 Stonegate 11 Lift Station and Pipeline Project Critical Areas Report The un-maintained areas of these parcels largely support dense shrubs (Scotch broom and Himalayan blackberry) and significant amounts of reed canarygrass. A few scattered deciduous trees (black cottonwood, red alder, and Sitka willow) are found in the areas, primarily along May ' Creek and the tributary intersecting the stream. The landscaped parcel contains lawn and ornamental plantings surrounding the existing lift station. 11 The proposed forced main alignment would travel from the proposed lift station west, along NE 26th Street crossing under a tributary of May Creek approximately 325-feet west of the lift station. The tributary flows under NE 26th Street through a 48-inch diameter corrugated metal culvert. 4.0 WETLAND DEFINITION AND REGULATIONS The characteristics of an area that result in its classification as "wetland" have been formally defined by federal and state agencies, as described in Appendix A. Numerous federal, state, and local regulations govern development and other activities in or near wetlands; at each level, there are typically several agencies charged with such powers (Ecology, 1994). Specific regulatory implications concerning the subject property are summarized later in this report. 5.0 METHODS Two levels of investigation were conducted for the analysis of wetlands on the subject property: a review of existing information and an on -site investigation. 5.1 Review of Existing Information A review of existing literature, maps, and other materials was conducted to identify wetlands or site characteristics indicative of wetlands on the subject property. These sources can only indicate the likelihood of the presence of wetlands; actual wetland determinations must be based upon data obtained from field investigations. Several documents were reviewed: • U.S. Geological Survey 1:24,000 Topographic Map, Mercer Island quadrangle (1992) • Soil Survey of King County Area, Washington, Snyder et al., 1973 • National Wetland Inventory, Mercer Island quadrangle (U.S. Fish and Wildlife Service, 1973) • Hvdric Soils List of King County (United States Department of Agriculture: Natural Resources Conservation Service, 2001) • City of Renton Critical Areas Inventory (Jones & Stokes Associates, 1992) Page 2 ESA Adolfson I August 2008 t 5.2 On -site Investigation Stonegate tt Lift Station and ine Project Critical Areas Report 5.2.1 Determining the Presence of Wetlands and Delineating Wetland Boundaries Methods defined in the Washington State Wetlands Identification and Delineation Manual (Ecology, 1997), a manual consistent with the U.S. Armv Corps of Engineers Wetlands Delineation Manual (Environmental Laboratory, 1987), were used to determine the presence and extent of wetlands on the subject property. Washington state and all local governments must use the state delineation manual to implement the Shoreline Management Act and/or the local regulations adopted pursuant to the Growth Management Act. The methodology outlined in the manual is based upon three essential characteristics of wetlands: (1) hydrophytic vegetation; (2) hydric soils; and (3) wetland hydrology. Field indicators of these three characteristics must all be present in order to determine that an area is a wetland (unless problem areas or atypical situations are encountered). The "routine on -site determination method" was used to determine the wetland boundaries. The routine method is used for areas equal to or less than five acres in size, or for larger areas with relatively homogeneous vegetative, soil, and hydrologic properties. Formal data plots were established where information regarding each of the three wetland parameters (vegetation, soils, and hydrology) was recorded. This information was used to distinguish wetlands from non -wetlands. If wetlands were determined to be present on the subject property, the wetland boundaries were delineated. Wetland boundaries were identified with sequentially numbered colored flagging imprinted with the words WETLAND DELINEATION. Data plot locations were also marked with colored flagging. As required by the City of Renton, visual observations were made of off -site areas from the parcel boundaries and public roads to determine if potential wetlands occur within 300 feet of the site. The methods used to assess wetland characteristics are described in greater detail in Appendix A. Please note that common plant names are used throughout this text; the scientific names are presented in Appendix B. 5.2.2 Classifying Wetlands Two classification systems are commonly used to describe wetlands. The hydrogeomorphic (HGM) system describes wetlands in terms of their position in the landscape and the movement of water in the wetland (Brinson, 1993). The U.S. Fish and Wildlife Service classification system (Cowardin et al., 1979) describes wetlands in terms of their vegetation communities; these include, for example, emergent, scrub -shrub, and forested community types. 5.2.3 Assessment of Aquatic Areas In addition to wetland areas, streams were identified in the vicinity of the project area. ESA Adolfson Page 3 August 2008 Stonegate H Lift Station and Pipeline Project Critical Areas Report 6.0 FINDINGS The following sections describe the results of the field investigation conducted by Ilon Logan, Laura Brock, and Scott Olmsted for the Stonegate Il Lift Station and Pipeline Project on February 141h and March 26`h, 2008. These sections describe the wetlands found in the project area, upland habitats, and wildlife observations. Seven (7) data plots were established within relatively uniform areas of vegetation on the site. Data sheets for each of the formal data plots evaluated for this project are provided in Appendix C. Stream observations were noted for May Creek and a tributary of May Creek located in the vicinity of the project area. 6.1 Existing Information The Soil Survey of King County Area (Snyder et al., 1973) maps two soil types in the project area: Bellingham silt loam and Ragnar-Indianola association. Bellingham silt loam is mapped on both sides of May Creek and is listed as hydric on the Hydric Soils of List of King County Area (USDA NRCS, 2001). These soils are poorly drained and formed in alluvium under grass and sedges. The Ragnar-Indianola association is comprised of equal parts Ragnar fine sandy loam and Indianola loamy fine sand. It is a well -drained soil that occurs on glacial outwash terraces. Ragnar-Indianola association is not listed as hydric. The National Wetland Inventory (NWI) shows palustrine emergent wetland recorded as temporarily flooded, partially drained/ditched (PEMAd) west of 148`h Avenue SE and on both sides of May Creek. East of 1481h Street, the NWI maps a larger palustrine emergent wetland complex that contains a semi -permanently flooded (PEMF) community and a seasonally flooded/well-drained and partially drained/ditched (PEMCd) community (Figure 2). Wetlands and stream corridors in the City of Renton were preliminarily identified in the City of Renton Critical Areas Inventory (Jones & Stokes Associates, 1992). The inventory shows the main stem of May Creek north of the existing Stonegate Lift Station and a tributary of May Creek extending south through the Stonegate residential development. A large scrub -shrub and I emergent wetland is also mapped along the mainstem of May Creek. The mapped wetland is identified as "K-7" and is 142 acres in size (Figure 2). ' Streams are also identified on the Renton Water Class Map (City of Renton, 2005) contained in the Renton Municipal Code (RMC). The map identifies May Creek and the tributary of May Creek that extends south through the project area (NE 26`h Street and SE 1041h Street) (Figure 2). ' 6.2 Wetlands Determinations Two wetlands were identified in the project area (Figure 3). Wetland A is part of a large 142 acre wetland that extends offsite to the north, east, and west (Figure 4). This large wetland was preliminarily identified in the Critical Areas Inventory (Jones & Stokes, 1992) and is mapped along the main stem of May Creek. Wetland B is associated with a tributary of May Creek and is located near the intersection of SE 1041h Street and 1481h Avenue SE (Figure 5). The following describes the wetlands and upland habitats found on the site. Page 4 ESA Adolfson ' August 2008 Stonegate H Lift Station and Pipeline Project Critical Areas Report 6.2.1 Wetland A Wetland A is located in the northern portion of the project area and contains a relatively uniform vegetation community and hydrologic regime (Figure 4). The wetland supports palustrine emergent (PEM) and scrub -shrub (PSS) communities, experiences seasonal saturation and/or inundation, and is connected to May Creek. A data plot dug to a depth of 18 inches was established to characterize soils and hydrology at the time of field investigation. The portions of the wetland adjacent to the stream are considered riverine wetlands under the HGM classification, while wetland areas further from the stream that are primarily groundwater driven are depressional. Wetland A is characterized by sample plot DP-4. Hydrology May Creek and a high groundwater table are the main sources of hydrology to the wetland. At the time of the site visit, no free water was present in DP-4; however, standing water 1-3 inches deep was located approximately 10 feet from the data plot and was present in other portions of the wetland. The field investigation occurred after a prolonged dry period without large storm events, and soils were moist to the surface, but not saturated. Saturation and inundation are likely early in the growing season based on the presence of hydrophytic species and redoximorphic features in the subsurface soils. In addition, DP-4 is located close to the wetland/upland boundary; therefore, indicators of wetland hydrology are not strong. Indicators of wetland hydrology, such as surface ponding and soil saturation, increased significantly within 5 feet of the data plot. Soils The soil at DP-4 consists of a surface layer that is a very dark brown (IOYR 2/2) loam that extends to about 16 inches below the surface. Below this layer is a lighter, grayish brown (1 OYR 5/2) silt loam soil that contains redoximorphic features (i.e., mottles) that are yellowish brown (1 OYR 5/8; medium and common) or yellowish red (5YR 5/8; medium and common) in color. Soil samples generally match the NRCS mapped soil unit, which is Bellingham silt loam. Ve etation Vegetation in the wetland is dominated by reed canarygrass and Douglas spirea (FACW), with scattered clumps of evergreen blackberry (FACU) primarily along the boundaries of the wetland. Red -osier dogwood (FACW) and Sitka willow (FACW) are present closer to May Creek. 6.2.2 Wetland B Wetland B is located in the southern portion of the project area and supports a palustrine forested (PFO) community (Figure 5). The wetland experiences seasonal saturation and/or inundation, and is connected to the tributary of May Creek that flows under SE 100 Street via a 24-inch culvert. The wetland is adjacent to the stream and is considered riverine under the HGM classification. Wetland B is characterized by sample plot DP-1 (Wetland B). A data plot dug to a depth of 18 inches was established to characterize soils and hydrology at the time of field investigation. ESA Adolfson Page 5 ' August 2008 Stonegate H Lift Station and Pipeline Project Critical Arens Report Hydrology The tributary of May Creek and a high groundwater table are the main sources of hydrology to Wetland B. At the time of the site visit, free water at 7 inches was present in DP -I (Wetland B); and the soil was saturated to the surface. Soils appeared to be saturated to the surface throughout the majority of the wetland. At the time of the site visit, the tributary contained approximately 4 to 6 inches of flowing water. Soils The soil consists of a surface layer that is a very dark gray (10YR 3/1) sandy loam that extends to about 8 inches below the surface. Below this layer is a reddish gray (2.5YR 5/1) loamy sand soil that contains mottles that are strong brown (7.5YR 4/6; medium and common) in color. Soil samples do not match the NRCS mapped soil unit, which is Ragnar-Indianola Association. The Ragnar-Indianola Association is not a hydric soil; however, the soils encountered were generally hydric. Vegetation Vegetation in the wetland is dominated by red alder (FAC), black cottonwood (FAC), Indian plum (FACU), reed canarygrass (FACW), with scattered slough sedge (OBL). 6.3 Streams and Other Drainage Features 6.3.1 May Creek The main channel of May Creek is located north of the proposed Stonegate II Lift Station on ' Parcel 803540TRCT, entering under the 148th Avenue SE Bridge and continuing offsite to the west. May Creek is approximately 10 to 15 feet wide where it crosses 148`h Avenue SE and narrows slightly, to approximately 5 to 8 feet, as it travels west. The depth of the stream is ' approximately 2 to 4 feet with a substrate composed of fine sediments. Riparian vegetation and Wetland A exist along the north and south banks of the stream, with dominant species including Sitka willow and reed canarygrass. May Creek is perennial or intermittent with known salmonid presence. The May Creek basin supports five species of salmonids: chinook, sockeye, and coho salmon, and steelhead and ' cutthroat trout (Kerwin, 2001). Since 2000, volunteers with the King County Volunteer Salmon Watchers Program have been observing salmon in May Creek. Volunteers have consistently seen sockeye salmon in the stream. Less commonly spotted are chinook salmon, coho salmon, ' cutthroat trout, and kokanee salmon. 6.3.2 Tributary of May Creek A tributary of May Creek enters the southern portion of the project area near Wetland B, and generally extends north until intersecting May Creek (Figure 2). ' The tributary of May Creek is a seasonal channel with an estimated 5-foot width and 1-foot depth in the vicinity of NE 26`h Street. The substrate is composed of finer sediments to the north and Page 6 ESA Adolfson ' August 2008 I Stonegate II Lift Station and Pipeline Project Critical Areas Report ' th coarser material closer to NE 26 Street. Dominant vegetation along this stream is similar to ' May Creek and includes Sitka willow, red alder, reed canarygrass, and Himalayan blackberry. In the vicinity of May Creek, the tributary has a less defined bed and banks, dispersing flow over ' a broad area. The tributary also contains dense herbaceous vegetation in this area. Therefore, salmonid presence in the tributary is unlikely; however, field investigations were conducted during low flow conditions. 1 d 1 The upstream portion of stream, in the vicinity of SE 104`h Street, travels along the property boundary of single family lots that contain maintained yards. The stream banks become armored upstream of the SE 104`h Street culvert as the stream passes under a wooden fence. The 24-inch corrugated metal culvert at SE 104`h Street empties near the confluence of the tributary of May Creek and a small stream entering the project area from the west. Downstream of the confluence, the tributary travels east for approximately 20 feet then turns to the north. The tributary is approximately 3 feet wide and 6 inches deep in the vicinity of SE 104`h Street. Dominant vegetation upstream of the culvert includes Indian plum, creeping buttercup, sword fern, cut -leaf blackberry, English holly, and red alder. Similar vegetation exists downstream of the culvert, with Himalayan blackberry and black cottonwood becoming common. 6.4 Upland Description Upland on Parcels 8035400580 and 803540TRCT The un-maintained upland area located in the northern parcels is characterized by DP-1, DP-2, and DP-3. Dominant vegetation includes reed canarygrass, Himalyan blackberry, evergreen blackberry, Canada thistle (FAC), and bracken fern (FACU). The soil investigation found a very dark brown (1 OYR 2/2), or brighter, sandy loam layer at the surface that extends to the bottom of the soil profile (+/- 18 inches). In several areas, this layer extends to approximately 7 inches, below which coarser and brighter soil exists. At the time of investigation, there was no soil saturation, or other indicators of saturation or inundation, at any of the upland plots. Based on the topographical position and the lack of soil saturation in upland soil pits dug around the site, it is likely that these areas will become drier during the early portion of the growing season. Upland on Proposed Force Main Alignment The upland area located east of the tributary is fairly uniform and characterized by DP-2. Dominant vegetation includes red alder, reed canarygrass, Himalayan blackberry, sword fern, and vine maple. The upland west of the tributary is characterized by DP-3. Dominant vegetation includes creeping buttercup (FACW), Himalayan blackberry, and herb Robert (NL). The soil investigation found a very dark brown (1 OYR 2/2) sandy loam layer at the surface that extends approximately 10 inches below the surface. Below this layer, the soil color and texture remain the same, but the layer contains mottles that are dark yellowish brown (1 OYR 4/6) to 16 inches. At the time of investigation, there was no soil saturation. There were no other indicators of saturation or inundation at either upland plot. Based on the topographical position and the lack of soil saturation in upland soil pits dug, it is likely that these areas will become drier during the early portion of the growing season. ESA Adolfson Page 7 ' August 2008 Stonegate H Li%t Station and Pipeline Project Critical Areas Report 6.5 Wildlife Wetland A provides habitat for wildlife species because it contains multiple vegetation classes, water sources, and is part of the May Creek corridor. It is also connected to Cougar Mountain Regional Wildland Park, located north of the project area. Bird species observed during field investigation included Steller's jay, red-tailed hawk, sharp -shinned hawk, American crow, Anna's hummingbird, black -capped chickadee, song sparrow, and pine stskin. Small mammals such as mice and vole are likely present as well as amphibian species. Large mammals, such as deer and coyote, also likely use the corridor and wetland. Other species of birds, mammals, reptiles, and amphibians in addition to those observed are expected to use habitat on the project site. For example, nocturnal species may be present that were not active during the site visit, or other species may only be highly visible or present in this area during certain seasons. Wetland B provides limited wildlife habitat due to its small size and level of human disturbance. However, the wetland is part of a riparian corridor that likely provides habitat to a number of species of birds, amphibians, and small mammals. 7.0 REGULATORY IMPLICATIONS Wetlands are regulated at the federal, state, and local levels. Agencies with jurisdiction include the U.S. Army Corps of Engineers (Corps), Washington State Department of Ecology (Ecology), ' and the City of Renton. The Washington Department of Fish and Wildlife (WDFW) regulates work within streams. Regulatory implications associated with development in wetlands and streams include, but may not be limited to, those discussed in this section. All applicable permits ' should be obtained prior to developing or otherwise altering streams or wetlands. 7.1 Federal Regulations The Corps regulates discharges of dredged or fill materials into waters of the United States, including wetlands, under Section 404 of the Clean Water Act. The purpose of the Clean Water Act is to "restore and maintain the chemical, physical, and biological integrity of the Nation's waters." A Section 404 permit may be required if a proposed project involves filling wetlands or altering streambeds or other waters of the U.S. The Corps will determine if wetlands are jurisdictional under Section 404 based upon the presence of a "significant nexus" to navigable waters (EPA and Corps, June 5, 2007). The Corps has established two types of permit programs under Section 404: nationwide and individual. Nationwide permits are issued when a proposed activity will have minimal adverse impacts to wetlands. All other projects are evaluated under the individual permitting process. The Corps determines which permitting process is used for a proposed project. The Corps will require that wetland impacts be avoided or minimized to the extent practicable, and mitigation will likely be required for unavoidable wetland impacts. Page 8 ESA Adolfson August 2008 Stonegate 11 Lilt Station and Pipeline Project Critical Areas Report 7.2 State Regulations The state certification process under Section 401 of the federal Clean Water Act is usually triggered through a Section 404 permit application. Section 401 directs each state to certify that proposed in -water activities will not adversely affect water quality or violate state aquatic protection laws. In Washington State, Ecology is responsible for administering the state certification program. Ecology may issue approval, approval with conditions, denial, or a request for delay due to lack of information. Any conditions attached to the 401 certification become part of the Section 404 permit. ' King County is one of the 15 coastal counties in Washington regulated under the Washington State Coastal Zone Management (CZM) Program. Activities that would affect coastal resources and involve approvals from the federal government (such as a Section 404 permit) must be evaluated for CZM compliance through a process called "federal consistency." Ecology administers the CZM program in this state. ' If relocation or alteration of stream culverts or other in -stream work is proposed as part of the project, a Hydraulic Project Approval (HPA) would be required from the Washington ' Department of Fish and Wildlife under the state Hydraulic Code (RCW 77.55, WAC 220-110). 7.3 Local Regulations ' The Renton Municipal Code details the parameters used for rating wetlands and streams in the City of Renton (RMC 4-3-050). Wetlands fall into three categories: Category I, II, and III and ' streams are in five classes: Class 1 through 5. Based on the criteria listed, Wetland A is considered a Category I wetland because it is greater than 10 acres in size, according to the Critical Areas Inventory (Jones & Stokes, 1992), and has three or more vegetation classes, one of which is open water (RMC 4-3-0550 MI). The wetland also includes May Creek, which contains listed salmonids, resulting in a Category I rating. Category I wetlands have a required standard buffer of 100-feet (RMC 4-3-050 M6). Wetland B is considered a Category III wetland because it is small in size, has low plant species richness and minimal wildlife use, and is surrounded by human disturbance (RMC 4-3-0550 M 1). Category III wetlands have a required standard buffer of 35-feet (RMC 4-3-050 M6). ' May Creek is considered a Class 2 stream because it is not a Shoreline of the state, has perennial flow with salmonid presence, and is mapped on Water Class Map as Class 2. Buffers for Class 2 streams are 100 feet. The tributary of May Creek is considered a Class 4 stream because it is a non -salmon -bearing ' intermittent stream and is mapped on Water Class Map as Class 4. Buffer widths for Class 4 streams are 35 feet. 1 ESA Adolfson Page 9 ' August 2008 Stonegate !! Lift Station and Pipeline Project Critical Arens Report Table 1. Aquatic Resource Classification and Rating Aquatic Resource Cowardin Class HGM Classification Rating Buffers Wetland A PEM/PSS Riverine/Depressional Category I 100-feet Wetland B PFO Riverine Category III 35-feet May Creek Class 2 100-feet Tributary of May Creek Class 4 35-feet ' To avoid and/or minimize impacts to aquatic resources located in the project area, construction activities and facility locations will not impact wetlands and streams or their buffers. Construction of the new force main may involve tunnel ing/directional drill methods in the vicinity of the tributary stream and NE 261h Street, which would not require in -water work or r cause impacts to the stream buffer. The proposed lift station near NE 26`h Street and 1481h Avenue SE has been located outside the 100-buffer of Wetland A to avoid buffer impacts. No ' impacts to critical areas are anticipated in association with this project. 8.0 LIMITATIONS I .1 Within the limitations of schedule, budget, scope -of -work, and seasonal constraints, we warrant that this study was conducted in accordance with generally accepted environmental science practices, including the technical guidelines and criteria in effect at the time this study was performed, as outlined in the Methods section. The results and conclusions of this report represent the authors' best professional judgment, based upon information provided by the - project proponent in addition to that obtained during the course of this study. No other warranty, expressed or implied, is made. Page 10 ESA Adolfson August 2008 I 1 11 1 1 C Stonegate tI Lift Station and Pipeline Project Critical Areas Report 9.0 REFERENCES Cowardin, L.M., V. Carter, F.C. Golet,.and E.T. LaRoe. 1979. Classification of Wetlands and Deepwater Habitats of the United States. FWS/OBS-79/31. U.S. Fish and Wildlife Service. Ecology (Washington State Department of Ecology). 1997. Washington State Wetlands Identification and Delineation Manual. Publication No. 96-94. Olympia, Washington. Environmental Laboratory. 1987. Corps of Engineers Wetlands Delineation Manual. Technical Report Y-87-1. U.S. Army Erigineer Waterways Experiment Station, Vicksburg, Massachusetts. Hitchcock, C.L., and A. Cronquist. 1973. Flora of the Pacific Northwest: An Illustrated Manual. University of Washington Press, Seattle, Washington. Hruby, T. 2004. Washington State Wetland Rating System for Western Washington — Revised. August 2004. Ecology publication number 04-06-025. Olympia, WA Munsell Color. 2000. Mansell Soil Color Charts. GretagMacbeth, New Windsor, New York. Renton Municipal Code (RMC). 2005. Title IV. Development Regulations, Chapter 3. Environmental Regulations and Overlay Districts. Renton, Washington. Available: http://www.codepublishing.com/WA/Renton/rentonO4/rentonO4O3.htm] Accessed: February 19, 2008. Snyder, D.E., P.S. Gale, and R.F. Pringle. 1973. Soil Survey of King County Area, Washington. U.S. Soil Conservation Service, Washington, DC. USFWS (U.S. Fish and Wildlife Service). 1993. 1993 Supplement to List of Plant Species that Occur in Wetlands: Northwest (Region 9). ESA Adolfson Page I I ' August 2008 ri I Stonegate 11 Lift Station and Pipeline Project Critical Arens Report 10.0 GLOSSARY agricultural wetland - Areas where wetland soils and hydrology remain, but hydrophytec vegetation has been removed to allow a crop to be grown. anaerobic - A situation in which molecular oxygen is absent (or effectively so) from the environment. atypical situation - Areas in which one or more wetland parameters (vegetation, soil, and/or hydrology) have been sufficiently altered by recent human activities or natural events to preclude the presence of wetland indicators of the parameter. "Recent" is intended to mean that period of time since legal jurisdiction of an applicable law began. best management practices (BMPs) — The physical, structural, and/or managerial practices that, when used singly or in combination, prevent or reduce pollutant discharges. buffer - A designated area along the edge of a stream or wetland that is regulated to control the negative effects of adjacent development from intruding into the aquatic resource. concretion - A local concentration of chemical compounds such as calcium carbonate or iron oxide in the soil that forms a grain or nodule of varying size, shape, hardness, and color. Concretions of significance in hydric soil are usually iron and/or manganese oxides occurring at or near the soil surface that develop under conditions of prolonged soil saturation. dominant species — Plant species that define the character of a vegetation community. In wetland delineation, this is typically measured using percent areal cover. For each stratum in the plant community (trees, shrubs, and herbs), dominant species are the most abundant plant species that when ranked in descending order of abundance and cumulatively totaled immediately exceed 50 percent cover for the stratum, plus any additional species that individually compose 20 percent or more of the total cover in the stratum. The list of dominant plant species is then combined across strata. (Corps of Engineers Wetland Delineation Manual, 1987) emergent - A plant that grows rooted in shallow water, the bulk of which emerges from the water and stands vertically. Usually applied to non -woody vegetation. emergent wetland - In the USFWS classification system (Cowardin et al., 1979), a wetland characterized by erect, rooted, herbaceous hydrophytes, excluding mosses and lichens. enhancement - An improvement in the functions and values of an existing wetland, typically through native plantings. fill material - Any material placed in an area to increase the surface elevation. forested wetland - In the USFWS classification system (Cowardin et al., 1979), a wetland characterized by woody vegetation that is six meters (20 feet) tall or taller. gleyed - A soil condition resulting from prolonged soil saturation, manifested by the presence of bluish or greenish colors throughout the soil or in mottles (spots or streaks) among other colors. herbaceous - Having the characteristics of an herb; a plant with no persistent woody stem above the ground. hydric soil — A soil that formed under conditions of saturation, flooding, or ponding long enough to develop anaerobic conditions in the upper part. hydrogeomorphic (HGM) classification — A system of classifying wetlands based on their position in the landscape and the movement of water within the wetland. hydrology — The science dealing with the properties, distribution, and circulation of water. Page 12 ESA Adolfson August 2008 Stonegate H Lift Station and Pipeline Project Critical Areas Report hydrophyte - Any plant growing in water or on a substrate that is at least periodically deficient ' in oxygen as a result of excessive water content. The sum total of hydrophytes in an area is known as "hydrophytic vegetation." in -kind compensation - Compensation for lost wetland habitat with a replacement wetland of the same habitat type. inundation — A condition in which water from any source temporarily or permanently covers a land surface. invasive plant species - Plant species that become established easily in disturbed conditions, reproduce readily, and often establish monocultures. Most invasive plants are non-native species; they were introduced to the Northwest intentionally or unintentionally by humans. ' Examples of common invasive species in the Pacific Northwest are Scot's broom, Canada thistle, hedge bindweed, English ivy, reed canarygrass, and purple loosestrife. lacustrine - In the USFWS classification system (Cowardin et at., 1979), lacustrine refers to a freshwater area that has all of the following characteristics: (1) situated in a topographic depression or a dammed river channel; (2) has less than 30% coverage of trees, shrubs, persistent ' emergent plants, mosses, or lichens; and (3) total area exceeds 20 acres. For areas less than 20 acres, an area is considered lacustrine if it has an active wave -formed or bedrock shoreline or is deeper than 6.6 feet in the deepest part. "Freshwater" means less than 0.5 parts per thousand ocean -derived salts. mitigation — Defined in WAC 197-11-766 as: (1) Avoiding the impact altogether by not taking a certain action or parts of an action; (2) Minimizing impacts by limiting the degree or magnitude of the action and its implementation, by using appropriate technology, or by taking affirmative steps to avoid or reduce impacts; (3) Rectifying the impact by repairing, rehabilitating, or restoring the affected environment; (4) Reducing or eliminating the impact over time by preservation and maintenance operations during the life of the action; (5) Compensating for the impact by replacing, enhancing or providing substitute resources or environments: and/or (6) Monitoring the impact and taking appropriate corrective measures. mottles - Spots or blotches of different color or shades of color interspersed within the dominant color in a soil layer. This usually results from periodic anaerobic conditions in the soil. 100-year floodplain - The flood with a 100-year recurrence interval; those areas identified as Zones A, A 1-30, AE, AH, AO, A99, V, V 1-30, and V E on most current Federal Emergency Management Agency (FEMA) Flood Rate Insurance Maps, or areas identified as 100-year floodplain on applicable local Flood Management Program maps. ordinary high-water mark - The line on the shore established by the fluctuations of water and ' indicated by physical characteristics such as a clear, natural line impressed on the bank; changes in the character of soil or vegetation; topographic shelves; or the presence of a line of litter or debris. ' out -of -kind compensation - Compensation for lost wetland habitat with a replacement wetland of a different habitat type. palustrine - In the USFWS classification system (Cowardin et al., 1979), palustrine refers to ' freshwater areas dominated by trees, shrubs, persistent emergent plants, mosses, or lichens. They ESA Adolfson page 13 August 2008 Stonegate H Lift Station and Pipeline Project Critical Arens Report can be non -tidal or tidal. Palustrine also includes wetlands lacking this vegetation but with the following characteristics: (1) area less than 20 acres; (2) no active wave -formed or bedrock shoreline; (3) water depth in the deepest part is less than 6.6 feet at low water. "Freshwater" means having less than 0.5 parts per thousand ocean -derived salts. ' persistent emergents — Emergent plants that remain standing at least until the beginning of the next growing season. reach - A length of stream channel with uniform characteristics. ' redoximorphic soil characteristics — Features of the soil such as masses, nodules, or mottles formed through reduction and oxidation of iron and manganese in seasonally saturated soils. restoration - To improve a disturbed or altered wetland by returning wetland parameters that ' may be missing. rhizosphere - The zone of soil surrounding a plant root in which interactions between the living root and microorganisms occur. riverine - In the USFWS classification system (Cowardin et al., 1979), riverine refers to freshwater areas that are contained within a channel and are not dominated by trees, shrubs, and ' persistent emergent plants. Examples include rivers and streams. "Freshwater" means having less than 0.5 parts per thousand ocean -derived salts. saturated soil conditions - A condition in which all easily drained spaces between soil particles in the root zone are temporarily or permanently filled with water. scrub -shrub - In the USFWS classification system (Cowardin et al., 1979), areas dominated by woody vegetation less than 6 meters (20 feet) tall. The species include tree shrubs, young trees, ' and trees or shrubs that are stunted because of environmental conditions. Section 404 permit - A permit issued by the U.S. Army Corps of Engineers under Section 404 of the federal Clean Water Act that allows an activity (filling) within a wetland. A 404 permit I usually requires compensation or mitigation for the wetland impacts. soil matrix - The portion of a given soil that has the dominant color. In most cases, the matrix is the portion of the soil having more than 50% of the same color. ' synonymy - Different scientific names for the same species. waters of the United States - As defined in 33 CFR Part 328, the term "waters of the United 1 States" means: 1. All waters which are currently used, or were used in the past, or may be ' susceptible to use in interstate or foreign commerce, including all waters which are subject to the ebb and flow of the tide; 2. All interstate waters including interstate wetlands; 3. All other waters such as intrastate lakes, rivers, streams (including intermittent streams), mudflats, sandflats, wetlands, sloughs, prairie potholes, wet meadows, playa lakes, or natural ponds, the use, degradation or destruction of which could affect interstate or foreign commerce including any such waters: i. Which are or could be used by interstate or foreign travelers for recreational or other purposes; or Page 14 ESA Adolfson ' August 2008 Stonegate H Lijt Station and Pipeline Project Critical Areas Report ii. From which fish or shellfish are or could be taken and sold in interstate or foreign commerce; or iii. Which are used or could be used for industrial purpose by industries in interstate commerce; 4. All impoundments of waters otherwise defined as waters of the United States under the definition; 5. Tributaries of waters identified in paragraphs 1-4; 6. The territorial seas; 7. Wetlands adjacent to waters (other than waters that are themselves wetlands) identified in paragraphs 1-6. Waste treatment systems, including treatment ponds or lagoons designed to meet ' the requirements of CWA (other than cooling ponds as defined in 40 CFR 123.11(m) which also meet the criteria of this definition) are not waters of the United States. 8. Waters of the United States do not include prior converted cropland. Notwithstanding the determination of an area's status as prior converted cropland ' by any other federal agency, for the purposes of the Clean Water Act, the final authority regarding Clean Water Act jurisdiction remains with the EPA. wetlands - Those areas that are inundated or saturated by surface or groundwater at a Ifrequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas (Federal Register, 1982, 1986). wetland boundary — The point on the ground at which a shift from wetlands to non -wetlands or ' aquatic habitat occurs. wetland hydrology - Wetland hydrology is considered to be present when there is permanent or periodic inundation or soil saturation at or near the soil surface for more than 12.5% of the growing season (typically two weeks in lowland Pacific Northwest areas). Areas that are inundated or saturated for between 5% and 12.5% of the growing season in most years may or may not be wetlands. Areas inundated or saturated for less than 5% of the growing season are 1 non -wetlands (Ecology, 1997). wetland indicator status (WIS) - Categories assigned to plant species based upon the estimated probabilities (expressed as a frequency of occurrence) of the species occurring in a wetland or a non -wetland. Wetland indicator status categories include the following: • Oblate (OBL): species that almost always occur in wetlands under natural conditions (estimated probability >99%). • Facultative wetland (FACW): species that usually occur in wetlands (estimated probability 67 to 99%), but are occasionally found in non -wetland areas. ESA Adolfson page 15 August 2008 Stonegate 11 Lift Station and Pipeline Project Critical Areal• Report • Facultative (FAQ: species that are equally likely to occur in wetlands (estimated probability 34 to 66%) or non -wetland areas. • Facultative upland (FACU): species that usually occur in non -wetland areas (estimated probability 67 to 99%), but are occasionally found in wetlands. • Upland (UPL): species that almost always occur in non -wetland areas under normal conditions (estimated probability >99%). A (+) or (-) following the WIS signifies a greater or lesser likelihood, respectively, of the species being found in wetland conditions. Plant species can also be designated "No indicator" or NI, which includes species for which insufficient information is available to determine status, or which were not evaluated by USFWS in compiling the WIS listings. Plant species that are not listed on the USFWS list of WIS ratings are designated "NU and are presumed to be upland 1 species. Page 16 ESA Adolfson I August 2008 Stonegate H Lift Station and Pipeline Project Critical Areas 1 FIGURES AND PHOTOGRAPHS I 1 Fj F L I ESA Adolfson page 17 ' August 2008 MouNratN ` LBELLEVUEj. S M MISH' �PA� sE tr ' REGIONAL I MERCERWILDLAND a4`{ semJ`f PARK I SLEAN DJ Pse a9>H `NEWCASTLE I�SSAQUAH s 1 n SE S SS SE z 9BT ^ 4 m S 9�Ne�t sE s2No ��^ s ,RENTON r _. 3 ST Sr RD f , PROJECT LOCATION --¢) SE MAY VALLEY �' KING COUNTY m143PD-�-r- \ j - - ¢ T PROPOSED N NE H !'oc, 27TZ PL STONEGATE II L= ' o - _J !a z 3 ¢ ,r Il LIFT STATION - — _Y"'S7 NE 25TH PL ` ' er.{ - - o z NE 25TH E _ s _ SE 1007H )1ST ST NE U 24TH [� SE 100THW Sr SE = a 100TH ST CO PL NE 74TH STc_v;vael PL in w T. 102ND ST Z U NE 23PD yE 23RD o a� CT ¢ ST ST NE W �(� sE PROPOSED FORCE' z z 22ND Pt Z �'' = sr T MAIN ROUTE* S 11 Zn,}I Q VE 21ST� '715` 1 c Tr z Z{/..pf . V' W c cT m PL C _ = NE Z, SE z Ne 20TH �¢I.� c Z NE 20TH Si o r-i - c� 104TH �- SE 104TH ST ST o 9TH ST E ' _ ' rf ls� Q SE NE N�Q SE 105TH PL 105TH rs 18TIl HE l z __ eEJ PL Z Sj MAN ST IN iH ZJ� le v} tr Q AV crFler„ sT tn%rH S7 ¢ ZF ti Cl ¢ v SE 107TH Z 17TH SE SE 1o;m vi. nr ieTN at o R NF 101TH PL 077H e ST = eni ST a L ST ie w r.E i N Pt MAY YALLEY _ W = N COUNTY PARK NE z 12TH a SE - P ._- z � SE 111TH PL \� _T 112TH ST _ I121H ST Mf SE 112TH ST o� z OLIVER M z k 112PI ET sE = SE 113TH 15500 1 v lrsn ST HAZEN w `iF s` - — CA AF- ltIIf ri SE i = ` ¢ NF t!rd-_1-.-,--.__ o SE 114TH ST NE 10TH a PL z - W o NE t'ni NE = E Z �10TH ST C' oL = _ SE 116TH 1T I =! - NE 9TH r AF; Q SE 116TH S1 iy;?il�i y ^ w < NE h y, Cr "E p?�� SE 9TH PL - - - --- - _. __ SE 117TH ST T ST NE 9TH ST SE 500 1000 2000 116TH 0 ¢ rZ I 1 T N Scale in Feet 'Force Main route recently revised due to easement constraints. SOURCE: Rand McNally & Company, 2006. Stonegate Lift Station and Pipeline . 207075 Figure 1 Vicinity Map Renton, Washington ,r taY Crees 'I• ^ �f r� 4EMAIL ' Proposed Stonegate 11,.,E v r. Lift Station PEMCD TOW Proposed For Main Route J _ ; • tip- i.1 Legend t Force Main Route' Streams Wetland (City of Renton) } " Wetland (King County) `� Wetland Type (NWI) e; !` PEMCD; Palustrine, Emergent, Seasonally Flooded, �. Seasonally Flooded Well -drained T PEMAD; Palustrine, Emergent, Temporary, Seasonally Flooded Well -Drained 0 680 1� I - Force main route recently revised due to Feet !�• easement constraints R i ' -- - — Renton Stonegate II . 2007 SOURCE: NWI; 2007, City of Kirkland; 2008, ESA Adolfson; 2008, King County; 2007 (wetland), 2002 (air photo) Figure 2 Wetlands and Streams - Existing Information Renton. WA i PROPOSED R F t Q 125 2 0 5Qo Feet SOURCE: Roth Hill, 2008 FIGURE 4. PROPOSED LIFT STATION, TRIBUTARY OF MAY CREEK, AND WETLAND A (LOCATED OUTSIDE WETLAND BUFFER) ZY OF MAY CREEK AND WETLAND B Stonegate II . 207075.01 Figure 3 Key Map Renton, Washington i 1 1 1 1 100' WETLAND BOFFER \ / ,SDP-1 DP-4 35' TRIBUTARY ! �!♦— BUFFER---, 100' WETLAND BUFFER ~ DP-3 1 PROPERTY LINE f � I rr _ Ok it WE - -i- -- PB ! - --- - NE 26TH ST W' W T I IE=321.0CB SOLID LID ! RIM=326.91 1 1(N)12-ADS WV 0 50 ! - - _. IE=321.01(W)12-CMP -- _ _ - _. - • + (2) r / Feet I SOURCE: ESA Adolfson; 2008, King County; 2007 PROPOSED LIFT STATION Renton Stonegate II .2007 Figure 4 Wetlands and Streams - Lift Station Renton. WA x ot Q 75 15 30 Feet SOURCE: Roth Hill, 2008 OH x FOUND RE/CAP DFA',PLS//17668 OHLJ off �Ij-----4 UNNAMED TRIBUTARY WETLAND B ' 35' WETLAND BUFFER \ CULVERT �IE=346.45 2e,"CMF CULVERT IE=346.54 — /— 24"CMP uv— --x— — — — I I / x III / L CULVERT OT FOUND RE/C IE=346.81 = "K.JOYLER PLS#554 I 24"CMIP / O 1 I I I 1 P O 35' TRIBUTARY BUFFER IO UNNAMED TRIBUTARY ' OHU LEGEND WETLAND — — — UNNAMED TRIBUTARY — — WETLAND AND STREAM BUFFER Stonegate II . 207075.01 Figure 5 Wetland B and Stream Renton, Washington �Lya 1 Y Photo 1. Wetland A; view northeast. February 14, 2008. Photo 2. Wetland A (reed canarygrass, foreground) and upland (blackberry, background); view west. February 14, 2008. I I n U Photo 3. Wetland A boundary in foreground and upland in background; view southeast. February 14, 2008. Photo 4. Upland area north of proposed lift station location, taken from 148" Ave SE; view southwest. February 14, 2008. sIlk 'may i`y�► j "�'� � ;� � r,�„ie 4r L ti Ac '� F ki VP 1.,— '.0), 1 , Photo 5. Tributary to May Creek north of SE 104`h St, Wetland B to right in photo; view north. March 26, 2008. Photo 6. Tributary to May Creek covered by blackberry, SE 104`h St to right in photo; view east. March 26, 2008. 1 1 1 1 1 1 1 1 1 1 ESA Adolfson August 2008 Stonegate 11 Lift Station and Pipeline Project Critical Areas Report APPENDIX A: METHODS USED TO EVALUATE WETLAND CHARACTERISTICS Appendix A I Stonegate H Lift Station and Pipeline Project Critical Areas Report Wetland Definition Wetlands are formally defined by the U.S. Army Corps of Engineers (Corps) (Federal Register 1982), the Environmental Protection Agency (EPA) (Federal Register 1988), the Washington Shoreline Management Act (SMA) of 1971 (Ecology, 1991) and the Washington State Growth Management Act (GMA) (Ecology, 1992) as ... those areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas (Federal Register, 1982, 1986). In addition, the SMA and the GMA definitions add: Wetlands do not include those artificial wetlands intentionally created from non - wetland site, including, but not limited to, irrigation and drainage ditches, grass - lined swales, canals, detention facilities, wastewater treatment facilities, farm ponds, and landscape amenities, or those wetlands created after July 1, 1990 that were unintentionally created as a result of the construction of a road, street, or highway. Wetlands may include those artificially created wetlands intentionally created from non -wetland areas to mitigate the conversion of wetlands. Methods defined in the Washington State Wetlands Identification and Delineation Manual (Ecology, 1997), a manual consistent with the U.S. Army Corps of Engineers Wetlands Delineation Manual (Environmental Laboratory, 1987), were used to determine the presence and extent of wetlands on the subject property. Washington state and all local governments must use the state delineation manual to implement the SMA and/or the local regulations adopted pursuant to the GMA. The methodology outlined in the manual is based upon three essential characteristics of wetlands: (1) hydrophytic vegetation; (2) hydric soils; and (3) wetland hydrology. Field indicators of these three characteristics must all be present in order to determine that an area is a wetland (unless problem areas or atypical situations are encountered). These characteristics are discussed below. Vegetation Plants must be specially adapted for life under saturated or anaerobic conditions to grow in wetlands. The U.S. Fish and Wildlife Service (USFWS) has determined the estimated probability of each plant species' occurrence in wetlands and has accordingly assigned a "wetland indicator status" (WIS) to each species (USFWS, 1988, 1993). Plants are categorized as obligate (OBL), facultative wetland (FACW), facultative (FAC), facultative upland (FACU), upland (UPL), not listed (NL), or no indicator status (NI). Definitions for each indicator status are listed in the Glossary. Species with an indicator status of OBL, FACW, or FAC are considered adapted for life in saturated or anaerobic soil conditions. Such species are referred to as "hydrophytic" vegetation. A (+) or (-) sign following the WIS signifies greater or lesser likelihood, respectively, of the species being found in wetland conditions. Areas of relatively homogeneous vegetative composition can be characterized by "dominant" species. The indicator status of the dominant species within each vegetative stratum is used to determine if the plant community may be characterized as hydrophytic. The vegetation of an area is considered to be hydrophytic if more than 50% of the dominant species have an indicator status of OBL, FACW, or FAC. ESA Adolfson Page A-1 August 2008 I Stonegate II Lift Station and Pipeline Project Critical Areas Report Sods Hydric soils are indicative of wetlands. Hydric soils are defined as soils that are saturated, flooded, or ponded long enough during the growing season to develop anaerobic conditions in the upper part of the soil profile (Federal Register, 1994). The Natural Resources Conservation Service (NRCS), in cooperation with the National Technical Committee for Hydric Soils, has compiled lists of hydric soils (NRCS, 1995). These lists identify soil series mapped by the NRCS that meet hydric soil criteria. It is common, however, for a map unit of non -wetland (non- hydric) soil to have inclusions of hydric soil, and vice versa. Therefore, field examination of soil conditions is important to determine if hydric soil conditions exist. The NRCS has developed a guide for identifying field indicators of hydric soils (NRCS, 1998). This list of hydric soil indicators is considered to be dynamic; revisions are anticipated to occur on a regular basis as a result of ongoing studies of hydric soils. Anaerobic conditions create certain characteristics in hydric soils, collectively known as "redoximorphic features," that can be observed in the field (Vepraskas, 1999). Redoximorphic features include high organic content, accumulation of sulfidic material (rotten egg odor), greenish- or bluish -gray color (gley formation), spots or blotches of different color interspersed with the dominant or matrix color (mottling), and dark soil colors (low soil chroma) (NRCS, 1998; Vepraskas, 1999). Soil colors are described both by common color name (for example, "dark brown") and by a numerical description of their hue, value, and chroma (for example, 10YR 2/2) as identified on a Munsell soil color chart (Munsell Color, 2000). Soil color is determined from a moist soil sample. Hydrology Water must be present in order for wetlands to exist; however, it need not be present throughout the entire year. Wetland hydrology is considered to be present when there is permanent or periodic inundation or soil saturation at or near the soil surface for more than 12.5% of the growing season (typically two weeks in lowland Pacific Northwest areas). Areas that are inundated or saturated for between 5% and 12.5% of the growing season in most years may or may not be wetlands. Areas inundated or saturated for less than 5% of the growing season are non -wetlands (Ecology, 1997). Indicators of wetland hydrology include observation of ponding or soil saturation, water marks, drift lines, drainage patterns, sediment deposits, oxidized rhizospheres, water -stained leaves, and local soil survey data. Where positive indicators of wetland hydrology are observed, it is assumed that wetland hydrology occurs for a sufficient period of the growing season to meet the wetland criteria, as described by Ecology (1997). Page A-2 ESA Adolfson August 2008 Stonegate H Lift Station and Pipeline Project Critical Arens Reporl I APPENDIX B: ' COMMON AND SCIENTIFIC NAMES OF PLANTS AND THEIR WETLAND INDICATOR STATUS 1 ESA Adolfson Appendix B ' August 2008 Stonegate 11 Lift Station and Pipeline Project Critical Arens Report PLANT SPECIES LIST FOR THE STONEGATE II LIFT STATION ' AND PIPELINE PROJECT, IDENTIFIED ON: February 141h and March 26, 2008 COMMON NAME SCIENTIFIC NAME WETLAND INDICATOR STATUS* Trees black cottonwood Populus trichocarpa (Popultts balsamifera ssp. trichocarpa) FAC English holly Iles ayuifolium NL red alder Alnus rubra FAC Sitka willow Saliv sitchensis FACW Shrubs Douglas' spiraea Spiraea douglasii FACW cut -leaf blackberry Rubus laciniattrs Himalayan blackberry Rubus discolor (Rubus armenicus) FACU Indian plum (osoberry) Oemleria ceraciformis FACU vine maple Acer circinatum FAC- Herbs bracken fern Pteridium aquilinum FACU Canadian thistle Cirsium arvense FACU+ creeping buttercup Ranunculus repens FACW herb Robert Geranium robertanium NL reed canarygrass Phalaris arundinacea FACW slough sedge Care_c obnupta OBL soft rush Jtncus eff isus FACW sword fern Polystichum munittun FACU L ESA Adolfson Page 13-1 ' August 2008 Stonegate 11 Lift Station and Pipeline Project Critical Areas *Key to Wetland Indicator Status codes — Northwest Region (Source: USFWS, 1988, 1993): ' OBL Obligate: species that almost always occur wetlands under natural conditions (est. probability >99%). FACW Facultative wetland : species that usually occur in wetlands (est. probability 67 to 99%), but are FAC occasionally found in non -wetlands. Facultative: Species that are equally likely to occur in wetlands or non -wetlands (est. probability 34 to 66%). FACU Facultative upland: species that usually occur in non -wetlands (est. probability 67 to 99%), but are ' occasionally found in wetlands. UPL Upland: species that almost always occur in non -wetlands under normal conditions (est. probability ' >99%). NL Not listed: species that are not listed by USFWS (1988, 1993) and are presumed to be upland species. NI No indicator: species for which insufficient information is available to determine status, or which ' were not evaluated by USFWS. + indicates a species that is more frequently found in wetlands - indicates a species that is less frequently found in wetlands * identifies a tentative assignment based upon either limited information or conflicting reviews Page B-2 ESA Adolfson August 2008 Stonegate II Lift Station and Pipeline Project Critical Areas APPENDIX C: WETLAND DETERMINATION DATA SHEETS ESA Adolfson August 2008 Appendix C 7 L DATA FORM 1 Routine Wetland Determination (WA State Wetland Delineation Manual or 1987 Corns Wetland Delineatinn Mnnnal) - --------- ------- Project Site: 7`rElf�i Date: 4 { $ Applicant/Owner: (�' }7�r Nf3�l County: State: 0111t Investi ator(s): u S/TYR: Do normal circumstances exist on the site? Y:) No Community ID: E7 t 15 N Is the site significantly disturbed (atypical situation)? Yes rN46 Transect ID: Is the area a potential problem area? Yes � Plot ID: VEGETATION Dominant Plant Species Stratum Percent Indicator Dominant Plant Species Stratum Percent Indicator cover cover 440.; .(:-YA;a1`b ra D �7RC.tA, %�canv�nf QrY1, 4(a, � y F,G HYDROPHYTIC VEGETATION INDICATORS: % of dominants OBL, FACW, & FAC: Check all indicators that apply & explain below: Regional knowledge of plant communities Wetland Plant List (Natl or regional) OTHER Physiological or reproductive adaptations Morphological adaptations Technical literature Wetland plant data base Hydrophytic vegetation present: Yes Rationale�for Decision/Remarks: � t� N �yitV t N dq n V uL. , W� HYDROLOGY Is it the growing season: Yes Water Marks: Yes Sediment Deposits: Yes o Based on: pArr S-v,v, s u.R v Drift Lines: Yes No--' Drainage Patterns: Yes q .... Dept. of inundation: mches Oxidized Root (live roots) Local Soil Survey: Yes No Channels <12 in. Yes Depth to free water in pit: 7 inches FAC Neutral: Yes 10 Water -stained Depth to saturated soil: 7 inches Leaves: Yes(6 Check all that apply & explain below: Other: Stream, lake or gage data: Aerial photographs: Other: Wetland hydrology present? Yes Rationale for decision/remarks: .a AS ate, . r, +j &1 54 I SOILS Map Unit Name i1_-'4 L-T LQ''1 Drainage Class 1�u�iZLyS.IiD (Series & Phase) Field observations confirm Taxonomy (subgroup) G UJ5�0-T jc zuef?�� mapped type? Yes No Profile Description Depth Horizon Matrix color Mottle colors Mottle abundance Texture, Drawing of soil (inches) (Munsell (Munsell size & contrast concretions, profile (match moist) moist) structure, etc. description) - �t 1 1 � �� Sar�C l A.. tk � e j �"L' 1��1u� cOA',sf'OA- ` i�fJhn1 Hydric Soil Indicators: (Check all that apply) Histosol Concretions Histic Epipedon High organic content in surface layer of sandy soils Sulfidic Odor Organic streaking in sandy soils Aquic moisture regime Listed on Local Hydric Soils List Reducing conditions Listed on National Hydric Soils List Gleyed or low-chroma colors Other (explain in remarks) Hydric soils present? Yes o Rationale for decision/remarks: 5-1 elder 5".. !' -"- /. "c %C' j"t •"r.'.`�"�'�Y'S, Wetland Determination (circle) Hydrophytic vegetation present? Yes Hydric soils present? Yes Is the sampling point within a wetland? Yes (No ; Wetland hydrology resent? Yes o �- Rationale/Remarks: '4s NOTES: Y,-a l i 0 x -14 d-, 5C ! A r,��rn �� r�/ Gtar jw✓•�r,t,� C,�1l�.,'�,�,r. Gr; r{r,,�Le ire'_ S' 'L JI DATA FORM 1 ' Routine Wetland Determination (WA State Wetland Delineation Manual or 1987 Coras Wetland Delineation Manual) 1 Project Site: c,-- Date: DZ�1�po Applicant/Owner: C._" R -1v1J County: viQ'y1 State:t Investi ator(s): \ U S/T/R: Do normal circumstances exist on the site? re No Community ID: "L.-,4 Is the site significantly disturbed (atypical situation)? Yes -,,ND Transect ID: up� Z!�' Is the area a potential problem area? Yes d96:�' Plot ID: DR_ 2 VEGETATION Dominant Plant Species Stratum Percent Indicator Dominant Plant Species Stratum Percent Indicator cover cover C A - 15 + HYDROPHYTIC VEGETATION INDICATORS: % of dominants OBL, FACW, & FAC: Y2 Check all indicators that apply & explain below: Regional knowledge of plant communities Wetland Plant List (Natl or regional) �_ OTHER Physiological or reproductive adaptations Morphological adaptations Technical literature Wetland plant data base Hydrophytic vegetation present: es No Rationale for Decision/Remarks: HYDROLOGY Is it the growing seasons No Water Marks: Yes Sediment Deposits: YesdSD Based on: �j Drift Lines: Yes Draina a Patterns: Yes Dept. of inundation: — inches Oxidized Root (live roots) Local Soil Survey: Yes No Channels <12 in. Yes (iVq: Depth to free water in pit: inches FAC Neutral: Yes Water -stained Depth to saturated soil: " inches Leaves: Yes as�D Check all that apply & explain below: Other: Stream, lake or gage data: Aerial photographs: Other: Wetland hydrology present? Yes dgE�) Rationale for decision/remarks: SOILS Mar Unit NameLY211 1 L-P-P1 Drainage Class L`/ (Series & Phase) Field observations confirm Taxonomy (subgroup) rif5'K_ tIC-R t— Ltz'JKA:p0e'O�mapped type? Yes No Profile Description Depth Horizon Matrix color Mottle colors Mottle abundance Texture, Drawing of soil (inches) (Munsell (Munsell size & contrast concretions, profile (match moist) moist) structure, etc. description) GLc� I —I F`J Hydric Soil Indicators: (Check all that apply) Histosol Concretions Histic Epipedon High organic content in surface layer of sandy soils Sulfidic Odor Organic streaking in sandy soils Aquic moisture regime Listed on Local Hydric Soils List Reducing conditions Listed on National Hydric Soils List Gleyed or low-chroma colors Other (explain in remarks) Hydric soils present? Yes Rationale for decisionlremarks: C419-c lA, Z Rcar -N�c Wetland Determination (circle) Hydrophytic vegetation present? ?6P No Hydric soils present? Yes C-'M Is the sampling point within a wetland? Yes Wetland hydrology resent? Yes 693P Rationale/Remarks: ' 3 d i7PA, NOTES: � Ply�� �(o �ErT CF 1�¢8�1f .t�o� Parma �vRR��� aY rhhat.sya,� `x�i. �f ri�ilf DATA FORM 1 ' Routine Wetland Determination (WA State Wetland Delineation Manual or 1987 Corps Wetland Delineation Manua 7 L Project Site: �41NLG A-M sue-- Date: /A 1G Applicant/Owner: O> ��-- County: N Investi ator(s): '�q) V State: V A S/T/R: Do normal circumstances exist on the site? ? No Community ID: U,/»l,/ I- P. Is the site significantly disturbed (atypical situation)? Yes Transect ID: Is the area a potential problem area? Yes Plot ID: . VEGETATION Dominant Plant Species Stratum Percent Indicator Dominant Plant Species Stratum Percent Indicator cover cover y. r'A� �� s arn,an�.L.c�s 5 ID yft4ll. HYDROPHYTIC VEGETATION INDICATORS: of dominants OBL, FACW, &FAC: Check all indicators that apply & explain below: Regional knowledge of plant communities Wetland Plant List (Natl or regional) OTHER Physiological or reproductive adaptations Morphological adaptations Technical literature Wetland plant data base Hydrophytic vegetation present: Yes o Rationale for Decisiomaemarks: ff Nei- MPYd 4l a n 501, 4. d -O ro oU Cry O i31. :' a• k HYDROLOGY Is it the growing season: Yes rN Water Marks: Yes o Sediment Deposits: Yes Based on: Drift Lines: Yes o Drainage Patterns: Yes Dept. of inundation: -- inches Oxidized Root (live roots) Local Soil Survey: Yes No Channels <12 in. Yes �l�o Depth to free water in pit: % 1 & inches FAC Neutral: Yes o Water -stained Depth to saturated soil: l inches Leaves: YesAo Check all that apply & explain below: Other: Stream, lake or gage data: Aerial photographs: Other: Wetland hydrology present? Yeso Rationale for decision/remarks: SOILS Map Unit Namur r A j C=Y_ h SI i T Drainage Class��/i (Series & Phase) Field observations confirm Taxonomy (subgroup) 1-1 r6le , 4Viapped type? Yes No Profile Description Depth (inches) Horizon Matrix color (Munsell moist) Mottle colors (Munsell moist) Mottle abundance size & contrast Texture, concretions, structure, etc. Drawing of soil profile (match description) D -I,8 A 10yrz y Hydric Soil Indicators: (Check all that apply) Histosol Concretions Histic Epipedon High organic content in surface layer of sandy soils Sulfidic Odor Organic streaking in sandy soils Aquic moisture regime Listed on Local Hydric Soils List Reducing conditions Listed on National Hydric Soils List Gieyed or low-chroma colors Other (explain in remarks) Hydric soils present? Yes Rationale for decision/remarks: Wetland Determination (circle) Hydrophytic vegetation present? Yes"- i Hydric soils present? Yes �0 Is the sampling point within a wetland? Yes tp Wetland hydrology resent? Yes �-Idoj Rationale/Remarks: 1\10 1^ d` c -14rrti-5 f r? s � NOTES: f ' .� � S i :� c...: •1 e-� .(�,...#�x yf �,c,.-IC-G,. � {� 5 j o � �-i�ra.-._- ;k �L) G� S f d i as e,— e DATA FORM 1 ' Routine Wetland Determination (WA State Wetland Delineation Manual or 19R7 rnrnc Wailond "alias n+4 X4 h 1 1 11 Project Site: ,7�Qcapm -TT Date: 'z'Ill✓�10 Applicant/Owner: C "l or, �M 0J17v,6J County: W-' NG State: 04 Investi ator(s): SD, Li S/T/R: Do normal circumstances exist on the site? C No Community ID: Is the site significantly disturbed (atypical situation)? Yes 4Iq Transect 1D: Is the area a potential problem area? Yes Lrw Plot ID: Ip VEGETATION Dominant Plant Species Stratum Percent Indicator Dominant Plant Species Stratum Percent Indicator cover cover VJ �V_ HYDROPHYTIC VEGETATION INDICATORS: % of dominants OBL, FACW, & FAC: G 7 � p Check all indicators that apply & explain below: Regional knowledge of plant communities Wetland Plant List (Natl or regional) `� OTHER Physiological or reproductive adaptations Morphological adaptations Technical literature Wetland plant data base Hydrophytic vegetation present: es No Rationale for Decision/Remarks: t +lr,td jb 90 c1 s� (-5 cs.��c 6r3L �L1� o� L HYDROLOGY Is it the growing season: Yes ]' o Water Marks: Yes o Sediment Deposits: Yes Na Based on: - - S ,L gvtV,v Drift Lines: Yes Drainage Patterns: Yes o Dept. of inundation: inches Oxidized Root (live roots) Local Soil Survey: Yes No Channels <12 in. Yes Depth to free water in pit: 7 inches FAC Neutral: Yes co Water -stained Depth to saturated soil: inches Leaves: Yes Check all that apply & explainbelow: Other: Stream, lake or gage data: Aerial photographs: Other: Wetland hydrology present? Yes o Rationale for decision/remarks:`J.wr_4_Ld Vo,c�-,�eJ ne..,,_iby (,J FD,141/ 11"11 /y�/�( / i '7A Cfr0,Q `G3sOv�r %a52Q-pyl. �J✓GSW,Ld, S(�IJii[ iOS JtY�fk �F� bx- dOIS\d(aS jtit.11 �o v,r4-t I- 5o, L y0- L Gy�O�,Ar -�b VJt4- ' r 0%kF� �ts rf�` v" 54v vq 11 n SOULS Map Unit Name --q�L4 i6bZN SI tT lc.4-t"1 Drainage Class t_Y W.Llpeb (Series & Phase) Field observations confirm Taxonomy (subgroup) t'IE6A!7,— �ER71C� mapped type? Yes No Profile Description Depth Horizon Matrix color Mottle colors Mottle abundance Texture, Drawing of soil (inches) (Munsell (Munsell size & contrast concretions, profile (match moist) moist) structure, etc. description) CO ,�� 44 pr^ ^ 0� �.AV 0 r�- nr,, Mmwr Hydric Soil Indicators: (Check all that apply) Histosol Concretions Histic Epipedon High organic content in surface layer of sandy soils Sulfidic Odor Organic streaking in sandy soils Aquic moisture regime Listed on Local Hydric Soils List Reducing conditions Listed on National Hydric Soils List Gleyed or low-chroma colors Other (explain in remarks) Hydric soils present? Ayes) No Rationale/for decision/remarks: /� d" I DYl) (L'r0 M,,O, - OW%-- �t(,S CN` t y�/L `rd,� O X.. Wetland Determination (circle) Hydrophytic vegetation present? Yew No Hydric soils present? ';Ms) No, % � is the sampling point within a wetland? (i;s) No Wetland hydrology resent? Yes Rationale/Remarks: i 1 (SSE 'M A d✓r•t) .fir 4r✓ nr�vti ( r,L rr -- Q, NOTES: �'-� ��u-,.,Mal Ctle, l— w:."p.I,; 6 O.FQrvx 1 11 ' DATA FORM 1 Routine Wetland Determination (WA State Wetland Delineation Manual or 1987 Corns Wetland Delineation Manual) 11 11 Project Site: ���� Date: �;? 2 c6 Applicant/owner: :A-N — County: State: l.JA, Investi ator(s): Sao L-� S/T/R: Do normal circumstances exist on the site? No Community ID: Is the site significantly disturbed (atypical situation)? Yes dQ Transect ID: oe- 3 Is the area a potential problem area? Yes cP Plot 1D: �P VEGETATION Dominant Plant Species Stratum Percent Indicator Dominant Plant Species Stratum Percent Indicator cover cover C> l� 20 J� 5 HYDROPHYTIC VEGETATION INDICATORS: 4X �C;, % of dominants OBL, FACW, & FAC: Check all indicators that apply & explain below: Regional knowledge of plant communities Wetland Plant List (Natl or regional) < OTHER Physiological or reproductive adaptations Morphological adaptations Technical literature Wetland plant data base Hydrophytic vegetation present: (YP No Rationale for Decision/Remarks: �� HYDROLOGY Is it the growing season: ne No Water Mark,: Yes Sediment Deposits: Yes IND Based on: A- -ft- c3r- -t>L>RUJL-y Drift Lines: Yes o) Drainage Patterns: Yes Dept. of inundation: inches Oxidized Root (live roots Local Soil Survey: Yes No Channels <12 in. Yes o Depth to free water in pit: inches FAC Neutral: re,, No Water -stained Depth to saturated soil: _� inches Leaves: Yes Check all that apply & explain below: Other: Stream, lake or gage data: Aerial photographs: Other: Wetland hydrology present'? e • No Rationale for decision/remarks: J (ATV �'r 1JC (�'j h� 'roQ 12t�• SOILS 50 ob / ' �' Map Unit Name —2,6404PE- WbhJh- 166C)C . Drainage Class tilr > t�E (Series & Phase) t Field observations confirm Taxonomy (subgroup) V1T12d� �(L D l mapped type'? Yes No Profile Description Depth Horizon Matrix color Mottle colors Mottle abundance Texture, Drawing of soil (inches) (Munsell (Munsell size & contrast concretions, profile (match moist) moist) structure, etc. descri tion) D' Q o R �► �- --� S - 8 2, 7, to Hydric Soil Indicators: (Check all that apply) Histosol Concretions Histic Epipedon High organic content in surface layer of sandy soils Sulfidic Odor Organic streaking in sandy soils Ayuic moisture regime Listed on Local Hvdric Soils List �C Reducing conditions Gleyed or low-chroma colors Listed on National Hydric Soils List Other (explain in remarks) Hydric soils present'? es No Rationale for decisionlreniarks: Wetland Determination (circle) Hydrophytic vegetation present'? e No Hydric soils present'? No Wetland hydrology resent? e. No Is the sampling point within a wetland'? No Rationale/Reniarks: NOTES: ' DATA FORM I Routine Wetland Determination (WA State Wetland Delineation Manual or 1987 Corns Wetland Dplineatinn Manual) Project Site: �--o,JEI�C[� Date: a3�a, Applicant'Owner: arTy pF Countv: V_IkdLt State:�k Investi gator(s): S/T/R: Do normal circumstances exist on the site'? No Community ID: Is the site significantly disturbed (atypical situation)'? es Transect ID: Lc-j>✓j F> Is the area a potential problem area? Yes CD Plot ID: VEGETATION Dominant Plant Species Stratum Percent Indicator Dominant Plant Species Stratum Percent Indicator cover cover 6 Rt�a I tJ �J I5 U HYDROPHYTIC VEGETATION INDICATORS: 2 0 ` % of dominants OBL. FACW. & FAC: Check all indicators that apply & explain below: Regional knowledge of plant communities Wetland Plant List (Natl or regional) _X OTHER Physiological or reproductive adaptations Morphological adaptations Technical literature Wetland plant data base Hydrophytic vegetation present: KD No Rationale for Decision/Remarks: 5(-- �d ln/a�aN HYDROLOGY Is it the growing season: No Water Marks: Yes Sediment Deposits: Yes o Based on: -ram r Drift Lines: Yes Drainage Patterns: Yes dSD Dept. of inundation: inches Oxidized Root (live roots) Local Soil Survey: Yes No Channels <12 in. Yes (170-' Depth to free water in pit: inches FAC Neutral: Yes ' o Water -stained Depth to saturated soil: I4 inches Leaves: Yes(5D Check all that apply & explain below: Other: Stream. lake or gage data: Aerial photographs: Other: Wetland hydrology present? Yes Rationale for decision/remarks: 1,�>Ir4f1N ii' � .140 �Rl'' .Y NNC4TT*R-e� ik.gir 2 sE4-cp.14 1 SOILS Map Unit Name =(C t0k, 12 tAP4 ll G (Series R Phase) Taxonomy (subgroup) q I T SIG j 6TV-cK6Pg�-1/ .� J Drainage Class 1,-DA Field observations confirm mapped type'? Yes No Profile Description Depth Horizon Matrix color Mottle colors Mottle abundance Texture. Drawing of soil (inches) (Mnmsell (Munsell size & contrast concretions, profile (match moist) moist) structure, etc. description) Q - 3ll g- I C& El2 i 4[ a-tt'r/ rI>7/ Hydric Soil Indicators: (Check all that apply) Histosol Concretions Histic Epipedon High organic content in surface laver of sandy soils Sulfidic Odor Organic streaking in sandy soils Aquic moisture regime Reducing conditions X Gleyed or low-chroma colors Listed on Local Hydric Soils List Listed on National Hydric Soils List Other (explain in remarks) Hydric soils present'? Nt� No Rationale for decision/remarks: i ov-- > Grif�t—(� �X Fr�RIZS1, Wetland Determination (circle) Hydrophytic vegetation present'? No Hydric soils present'? No Is the sampling point within a wetland'? Yes No) Wetland hydrology resent'? Yes o Rationale/Remarks: HOT- AAA - NOTES: ' DATA FORM I Routine Wetland Determination (WA State Wetland Delineation Manual or 1987 CorDS Wetland Delineation Mannnh Project Site: gr�j� j Date: 02 mpg Applicant!Owner. G"y pf 9,6)4'rcr-1 County: KI►� State: ►.-->A Investi ator(s): 1jd S/T/R: Do normal circumstances exist on the site? es No Community ID: Is the site significantly disturbed (atypical situation)? Yes, Transect 1D: 1•� T 6 Is the area a potential problem area? Yes t T Plot [D: �P- 3 - uF VEGETATION Dominant Plant Species Stratum Percent Indicator Dominant Plant Species Stratum Percent Indicator coecr cover Wb 5 20 vJ -�T -T--- HYDROPHYTiC VEGETATION INDICATORS: % of dominants OBL. FAC W. & FAC: �Z o Check all indicators that apply & explain below: Regional knowledge of plant communities Wetland Plant List (Natl or regional) OTHER Physiological or reproductive adaptations Morphological adaptations Technical literature Wetland plant data base Hydrophytic vegetation present: es No Rationale for DecisiotvReniarks: fAL- c)P- i e-ITZE . HYDROLOGY Is it the growing season: es- No Water Marks: Yes Sediment Deposits: Yes t Based on: Drift Lines: Yes CIS Drainage Patterns: Yes <ND Dept. of inundation: inches Oxidized Root (live roots) Local Soil Survev: Yes No Channels <1? in. Yes Depth to free water in pit: inches FAC Neutral: Yes Water -stained Depth to saturated soil: inches Leaves: Yes` i Check all that apply & explain below: Other: Stream, lake or gage data:�� tat, Aerial photographs: Other: Wetland hydrology present'? Yes Rationale for decision/reniarks: �htil 12 "JC> 1TL1i"P1�2� z_ s Ir-ADtC t4UE �P—Cfnrr L I I SOILS jalo /5c:70 `jv fv I� - Map Unit Name Q.- jt p&—*C A Drainage Class J lSeries & Phase)Zdl Field observations confirm Taxonomy (subgroup)Dy2T1QA6991,1i1-j/ mapped type? Yes No Profile Description Depth Horizon Matrix color Mottle colors Mottle abundance Texture. Dra«ring of soil (inches) (Munsell (Munsell size & contrast concretions, profile (match moist) moist) structure, etc, description) �- O ,k o 212- l o `i �"1rt�i'i6 D 'D( sa�� Hydric Soil Indicators: (Check all that apply) Histosol Concretions Histic Epipedon High organic content in surface layer of sandy soils Sultidic Odor Organic streaking in sandy soils Aquic moisture regime Listed on Local Hydric Soils List Reducing conditions Listed on National Hydric Soils List Gleyed or low-chroma colors Other (explain in remarks) Hydric soils present? Yes Rationale for decision/remarks: t•10 l�lG��drL� i� � Wetland Determination (circle) Hydrophytic vegetation present'? �a No Hydric soils present'? Yes (tlD Is the sampling point within a wetland'? Yes —Wetland hydrology resent'? Yes Rationale/Remarks: NOTES: Appendix E RE N T O N Stonegate II Facility Evaluation Appendix E Preliminary Getechnical Report (HWA GeoSciences) ' Rot Hill 5 FINAL GEOTECHNICAL REPORT Renton-Stonegate II Sewer System Improvements Project Renton, Washington HWA Project No. 2007-080-21 Task 1200 Prepared for Roth Hill Engineering Partners LLC November 7, 2008 =A, HWAGEOSCIENCES INC. 1 1 1 1 1 1 1 rfT HWA GEOSCI ENCES INC. November 7, 2008 HWA Project No. 2007-080-21 T1200 Roth Hill Engineering Partners LLC 2600 116th Avenue NE, Suite 100 Bellevue, Washington 98004 Attention: Erik Waligorski, P.E. Subject: FINAL GEOTECHNICAL REPORT RENTON-STONEGATE II SEWER SYSTEM IMPROVEMENTS PROJECT Renton, Washington Dear Mr. Waligorski: This letter transmits our final geotechnical report for the Renton-Stonegate 11 Sewer System Improvements Project in Renton, Washington. We appreciate the opportunity to provide geotechnical services for this project. Should you have any questions or comments concerning our enclosed report, or if we may be of further service, please call. Sincerely, HWA GEOSCIENCES INC. L� Steven I-. Greene, L.E.G. Vice I'resident SI:G:EOA:seg Erik 0. Andersen, P.E. Geotcchnical Group Mauagcr 197 M h4th Avenue W. Suite 200 Lynnwood, WA 98036.5957 Tel: 4 2 .774.0106 Fix: 425.774.2714 www.hwageo.coni 1.0 2.0 3.0 4.0 TABLE OF CONTENTS Page INTRODUCTION................................................................................................... 1 1.1 GENERAL......................................................................................................1 1.2 PROJECT DESCRIPTION................................................................................. 1 1.3 SCOPE OF SERVICES AND AUTHORIZATION................................................... 2 FIELD EXPLORATION AND LABORATORY TESTING.................................2 2.1 FIELD EXPLORATION.................................................................................... 2 2.2 LABORATORY TESTING................................................................................ 3 SITECONDITIONS............................................................................................... 3 3.1 SURFACE CONDITIONS.................................................................................. 3 3.2 SITE GEOLOGY............................................................................................. 4 3.3 SUBSURFACE CONDITIONS........................................................................... 4 3.3.1 NE Field Avenue (BH-IA through BH-4B).................................4 3.3.2 NE 20th Street(BH-5)..................................................................5 3.3.3 Lyons Avenue NE(BH-6)............................................................6 3.3.4 147th Avenue SE (BH-7)............................................................. 7 3.3.5 148th Avenue SE (BH-8)............................................................. 8 3.3.6 Stonegate-Summerwind Connector (BH-9 & BH-10) ................. 9 3.3.7 NE 26`h Street Culvert Under -crossing (BH-13 & BH-14)........ 10 3.3.8 Proposed Stonegate II Lift Station (BH-I I & BH-12)............... 12 3.3.9 Summary of Soil Conditions...................................................... 13 RECOMMENDATIONS...................................................................................... 15 4.1GENERAL ...................................................................................................... 15 4.2 STONEGATE II LIFT STATION....................................................................... 15 4.2.1 Temporary Shoring...................................................................... 15 4.2.2 Ground Water Control / Dewatering............................................ 16 4.2.3 Lift Station Excavation................................................................ 17 4.2.4 Buoyancy..................................................................................... 17 4.3 PIPE BURSTING............................................................................................. 17 4.4 HORIZONTAL DIRECTIONAL DRILLING......................................................... 20 4.5 OPEN CUT TRENCHING ..................... 21 4.5.1 Soil Excavation Characteristics................................................... 21 4.5.2 Sloped Open -Cut Excavations..................................................... 21 4.3.1 Shored Excavations.................................................................... 22 4.3.2 Ground Water and Construction Dewatering .............................23 4.3.3 Pipeline and Manhole Settlement...............................................23 4.3.4 Pipeline Support and Bedding....................................................24 4.3.5 Trench Backfill Materials and Compaction ............................... 24 4.3.6 Pipeline and Buried Structure Design Considerations ............... 26 L� November 7, 2008 HWA Project No. 2007-080-21 T1200 4.3.7 Jacking and Insertion Pits .......................................... 4.4 SEISMIC CONSIDERATIONS........................................................ 4.5 WET WEATHER EARTHWORK .................................................... 4.6 DRAINAGE AND EROSION CONSIDERATIONS ............................. 5.0 CONDITIONS AND LIMITATIONS ................................................. 6.0 REFERENCES..................................................................................... LIST OF FIGURES Figure 1 Project Site & Vicinity Map Figure 2 Project Alignment and Exploration Locations Figures 3 - 5 Site and Exploration Plan Maps Figure 6 Design Earth Pressures for Temporary Braced Shoring Figure 7 Parameters for Calculating Uplift Resistance APPENDIX A — EKPLORATION LOGS Figure A-1. Legend of Terms and Symbols Figures A-2 through A-19. Logs of Exploratory Borings (BH-1 — BH-14) APPENDIX B — LABORATORY TESTING Figures B-1 through B-8. Particle -Size Analysis of Soils Figure B-9. Atterberg Limits 27 27 28 29 29 31 Stonegate II Final Geotech Report.doc ii HWA GeoSciences Inc. ' FINAL GEOTECHNICAL REPORT RENTON-STONEGATE II SEWER SYSTEM IMPROVEMENTS PROJECT RENTON, WASHINGTON 1.0 INTRODUCTION ' 1.1 GENERAL This report presents the results of a geotechnical engineering study completed by HWA ' GeoSciences Inc. (HWA) for Roth Hill and the City of Renton Public Works. Currently, the existing residential developments known as Summerwind and Stonegate are served by separate gravity collection systems, lift stations, and force main conveyance systems. The purpose of this project is to combine the flows and utilize a single force main system. This will be accomplished by converting the existing Summerwind lift station into a manhole and installing new gravity sewer between the converted wet well and the existing Stonegate sewer manhole located in NE 24`h Court. The combined Summerwind and Stonegate flows will then be conveyed by the existing Stonegate gravity system to a new lift station located adjacent to the existing Stonegate lift station at the northwest corner of NE 26`h Street and 1481h Avenue SE. It is assumed that the ' existing Stonegate gravity sewer has sufficient capacity to handle the increased flow. From the new Stonegate lift station, combined flow will be conveyed via force main uphill to the west, and southwest along NE 26th Street and Lyons Avenue NE, NE 22nd Court, along an easement between the two developments connecting to NE 20`h Street, and the gravity system on ' NE Field Avenue. The existing NE Field Avenue system is constructed of mostly 8-inch diameter PVC and the pipe will be replaced/upsized to handle the increased flow. The location of the project and project alignment is shown on the Project Site & Vicinity Map, and the Project Alignment and Exploration Locations on Figures 1 and 2, respectively. The general layout of the roadway and the location of the existing pipeline system are shown on Figures 3 through 5. The purpose of this geotechnical investigation was to plan, conduct and present the results of our geotechnical explorations and provide geotechnical recommendations for the design and construction of the planned improvements. 1.2 PROJECT DESCRIPTION The project will include design and construction of gravity connector lines between the existing Summerwind and Stonegate systems, using horizontal directional drilling methods; a new Lift Station north of the existing Stonegate lift station that will handle the combined flows; a new force main to convey sewage up to NE Field Avenue; and upsizing of the existing gravity November 7, 2008 HWA Project No. 2007-080-21 T1200 conveyance along NE Field Avenue. The conveyance alignment is typically situated along a series of two-lane residential streets. Open excavation for the new force main will have some impact on local traffic, and will require surface restoration. At the culvert crossing along NE 26`h Street, open trench construction and horizontal directional drilling(HDD) are under consideration. Design and construction of the new lift station will require shored excavations and dewatering. Upsizing of the existing gravity conveyance system along NE Field Avenue is expected to employ trenchless technologies (such as pipe -bursting) to minimize potential damage to the existing roadway. 1.3 SCOPE OF SERVICES AND AUTHORIZATION The purpose of the geotechnical investigation work tasks was to characterize the subsurface conditions along the project alignment so that recommendations for design and construction of the proposed sanitary sewer and lift station replacement improvements could be made in support of the Roth Hill design team. Our work tasks were performed in general accordance with the scope of work, as described in our Sub -consultant Agreement executed on March 7th, 2008; supplemented in August of 2008. Our scope of work did not include environmental assessment of the project alignments. 2.0 FIELD EXPLORATION AND LABORATORY TESTING 2.1 FIELD EXPLORATION Our field investigation consisted of 18 borings, designated as BH-lA and I through 4A and 413 (8 borings), and BH-5 through BH-14 (8 borings), to explore the subsurface conditions along the proposed project alignment, both ends of the Stonegate — Summerwind connection, and at the new lift station location. The borings were conducted at the locations proposed previously in our Exploration Plan. The approximate boring locations are shown on the Site and Exploration Plan drawings, Figures 3 through 5. ' The borings were conducted on May 7`h, May 81h, and June 4th, 2008, by Gregory Drilling of Redmond, Washington, and Davies Drilling of Snohomish, Washington. The borings were advanced using truck and a track -mounted drill rigs, respectively, under the direction of an HWA ' geologist. Supplemental borings for the culvert crossing along NE 26`h Street were conducted on September 11 `h, 2008, by Holocene Drilling of Graham, Washington, using a truck -mounted drill rig. The borings were advanced to depths ranging between approximately 5 and 41.5 feet below ' the ground surface. Standard Penetration Tests (SPTs) were performed at 5 and/or 2'/2-foot intervals in each of the borings in general accordance with ASTM D-1586. The SPT consists of driving a 2-inch O.D. split -spoon sampler a distance of 18 inches into the bottom of the borehole ' with a 140-pound hammer falling 30 inches. The number of blows required to drive the sampler each of three 6-inch increments was recorded, and the number of blows required to cause the last Stonegate II Final Geotech Report.doc 2 HWA GeoSciences Inc. H November 7, 2008 HWA Project No. 2007-080-21 T1200 12 inches of penetration was termed the SPT (N-value). This value is an indicator of the relative in situ density or consistency of the soils. Piezometers for measuring ground water levels were installed in borings 131-1-5, 131-1-7, BH-I I and BH-13. They consisted of slotted, 2-inch PVC, standpipes installed to near the bottom of the borings. The annulus around the slotted portions of the pipes was backfilled with No. 10-20 Colorado Sand, and a cement slurry seal and locking monument casing were placed at the ground surface to prevent inflow of surface water. The piezometer installations are shown schematically illustrated on the boring logs, as appropriate. These piezometers are the property of the City of Renton. During or after construction of this project, the piezometers will need to be abandoned in accordance with Ecology requirements. HWA can assist with piezometer abandonment, if requested, but the costs of future abandonment are not included within our scope of work. HWA personnel recorded pertinent information including, blow counts, soil sample depths, stratigraphy, soil engineering characteristics, and ground water occurrence as the explorations were advanced. Soils were classified in general accordance with the classification system described in Figure A-1, which also provides a key to the exploration log symbols. The summary logs are presented in Figures A-2 and A-19. The stratigraphic contacts shown on the individual logs represent the approximate boundaries between soil types. The actual transitions may be more gradual. 2.2 LABORATORY TESTING Laboratory tests were conducted on selected samples obtained from the explorations to characterize engineering and index properties of the project soils. Laboratory tests included determination of in -situ moisture content, grain size distribution, and Atterberg Limits. The tests were conducted in general accordance with appropriate American Society of Testing and Materials (ASTM) standards. The results are discussed in further detail and are presented in Appendix B, or are displayed on the exploration logs in Appendix A, as appropriate. 3.0 SITE CONDITIONS 3.1 SURFACE CONDITIONS The project is situated along a sloping glacial upland area south of May Creek in northeastern Renton, Washington. The project is located on relatively quiet residential streets having two paved traffic lanes and typically room for parked vehicles on at least one or both sides. The site for the planned new Stonegate II lift station is north of the existing Stonegate lift station on an alluvial plain south of May Creek. Stonegate II Final Geotech Report.doc 3 HWA GeoSciences Inc. ' November 7, 2008 HWA Project No. 2007-080-21 T1200 ' 3.2 SITE GEOLOGY ' Geologic information for the project area was obtained from a map titled Composite Geologic Map of King County, Washington (D.B. Booth et al, 2006) published by the U.S. Geological Survey. Near -surface deposits in the project vicinity are mapped as Vashon glacial till. Near the ' banks of May Creek, glacial soils have been reworked or eroded and/or replaced with alluvial soils. ' Vashon till generally consists of a very compact unsorted mixture of clay, silt, sand, and gravel, deposited directly by the Puget Lobe of the Cordilleran Ice Sheet. It was consolidated by several thousand feet of glacial ice and is, therefore, very dense. Locally, the Vashon till may be ' overlain by a layer of recessional outwash, consisting of loose to medium dense sand and gravel that was deposited by glacial meltwater emanating from the receding glacial front. Additionally, the Vashon till may be underlain by advance outwash, consisting of dense gravelly sand. Advance outwash was deposited by meltwater flowing from the advancing glacial front and, consequently, was over -ridden and consolidated by the weight of the glacial ice. ' May Creek alluvial soils typically consist of loose to medium dense sands, gravels and silts derived from existing glacial soils or colluvium. Colluvium is slope -wash material originating ' on and transported down steep slopes by local weathering processes (i.e. runoff and mass wasting). 3.3 SUBSURFACE CONDITIONS Our explorations encountered glacial till in most locations, which generally agrees with the geologic map description. Man -modified fill materials were encountered above the existing sewer trench on Field Avenue, and along the proposed alignment beneath roadways. Recent alluvium, recessional glacial outwash, recessional glacial lacustrine, glacial till and advance ' glacial outwash soils were encountered at locations near May Creek, such as the culvert crossing at NE 26`h Street and the area proposed to accommodate the new Stonegate II lift Station. ' 3.3.1 NE Field Avenue (BH-IA through BH-413) Exploration borings were conducted in pairs, located within (borings designated as A) and outside (borings designated as B) the existing sewer trench limits, so that the engineering ' properties of the existing trench backfill and the adjacent local native soils could be characterized. In general, the native subsoil along the NE Field Avenue alignment ' predominately consists of very dense glacial till soils, locally overlain by native fills of varying thickness. The existing sewer trenches appear to have been backfilled with native trench spoil materials comprised predominately of loose to medium dense silty sand and gravelly silt, which ' was likely derived from on -site trench excavations in glacial till. No ground water seepage was observed while conducting these borings along NE Field Avenue. Stonegate II Final Geotech Report.doc 4 HWA GeoSciences Inc. 1 November 7, 2008 HWA Project No. 2007-080-21 T1200 The approximate locations of these borings are shown on Figures 3A through 3C. The soil units encountered in our borings, or anticipated outside of the existing sewer alignment along NE Field Avenue, are described below, with materials interpreted as being youngest in origin and nearest the surface described first. • ACP Surfacing — ACP (asphaltic concrete pavement) was encountered at the surface at bore holes BH-la through 4b, where it was typically 0.4 feet (5 inches) thick over the sewer trench and 0.2 feet (2%2 inches) thick about 5 feet towards the curb, respectively. • Road Base — Immediately beneath the existing ACPsurfacing, roadway fill consisting of medium dense to dense, gray, sandy gravel was encountered. Apparently, this material was placed as base prior to paving NE Field Avenue. The road base aggregate ranged from 0.6 to 0.8 feet (7 to 10 inches) in thickness. • Fill —Immediately beneath the existing road base, in 131-1-113, 213, 313 and 413 (located outside the sewer trench limits), fill consisting of medium dense to very dense, brown to olive gray, silty sand with gravel was encountered. This material was likely placed during construction of NE Field Avenue. The fill ranged from 1.0 to 4.0 feet in thickness. • Trench Backfill — Existing sewer trench backfill, consisting of trench spoils comprised predominately of medium dense to loose, olive brown to gray, silty sand with gravel to gravelly silt with sand, was encountered in borings BH-1 A, 2A, 3A, and 4A within the existing sewer trench limits. The trench backfill explored ranged from 5 to 6 feet in thickness. The trench backfill material was not fully penetrated by our borings, as all four of the borings were terminated at least 1-foot above the existing sewer pipe crown to avoid damaging the pipe. Evaluation of natural soil moisture content and SPT data for this material indicates that is was probably placed loosely and wet of what is optimum for adequate compaction. These soils will, accordingly, be relatively easy to displace during pipe - bursting operations. Vashon Till — In general, native glacial till, consisting of dense to very dense, gray, silty sand with gravel to silty gravel with sand, was encountered in the borings outside of the trench line (all B borings), and constitutes the local native soil unit that will be encountered during construction. 3.3.2 NE 20th Street (BH-5) This location is along the western end of the proposed force system alignment before it ties in to the existing gravity system situated along NE Field Avenue, and may locally accommodate a receiving pit should the new force main be installed by directional drilling methods. The approximate location of this boring is shown on Figure 3D. Therefore, our exploration boring (131-1-5) was conducted with closely spaced (2.5 foot) sampling intervals in the upper Stonegate II Final Geotech Report.doc 5 HWA GeoSciences Inc. November 7, 2008 H WA Project No. 2007-080-21 T 1200 10-11.5 feet, and with more widely spaced (5 foot) intervals once the boring was well into very dense native soils, to characterize the engineering properties of local fill and native soils, and attempt to detect local ground water seepage. In general, the NE 20`h Street location is underlain by native subsoil, predominately consisting of very dense glacial till soils, locally overlain by medium dense weathered till and native fills of varying thickness. 131-1-5 was conducted to a final depth of 31 feet below the existing ground surface. No ground water seepage was observed while conducting boring 131-1-5 on NE 20`h Street. The soil units encountered in this boring are described below, with materials interpreted as being youngest in origin and nearest the surface described first. • ACP Surfacing — ACP (asphaltic concrete pavement) was encountered at the surface at 131-1-5, where it was about 0.2 feet (2'/z inches). • Road Base — Immediately beneath the existing ACP surfacing, roadway fill consisting of medium dense, gray, sandy gravel was encountered. Apparently, this material was placed prior to paving NE 20`h Street. The road base aggregate at this location was about 0.3 feet (3'/z inches) in thickness. ' • Weathered Till — Immediately beneath the existing road base in 131-1-5, weathered till consisting of medium dense, olive gray, silty fine to medium sand with gravel was encountered. This material represents native glacial till soil that was subject to weathering prior to the construction of NE 201h Street. The weathered till at the location of 131-1-5 was about 5% feet in thickness. This soil will provide adequate bearing for a sewer pipeline. 1 • Vashon Till — In general, native glacial till, consisting of dense to very dense, gray, silty sand with gravel to silty gravel with sand, was encountered in the 131-1-5 beneath the layer of weathered till, and constitutes the deepest local native soil unit encountered during drilling at this location, where it was in excess of 24 feet thick and not fully penetrated. This soil will provide excellent bearing for a sewer pipeline. 3.3.3 Lyons Avenue NE (BH-6) This location is down slope of boring 131-1-5, situated at the southern terminus of Lyons Avenue NE. The approximate location of this boring is shown on Figure 3D. At this location, 131-1-6 was conducted with closely spaced (2.5 foot) sampling intervals in the upper 6.5 feet, and more widely spaced (5 foot) intervals once the boring encountered very dense native soil to characterize the engineering properties of the local subsoils and attempt to detect local ground water seepage. In general, this NE Lyons Avenue location is underlain by native subsoil, predominately consisting of very dense glacial till soils that are locally overlain by medium dense, weathered till and native fills of varying thickness. 131-1-6 was conducted to a final depth of 20%z feet below the existing ground surface. No ground water seepage was observed while conducting boring 131-1-6 on NE Lyons Avenue. Stonegate II Final Geotech Report.doc 6 HWA GeoSciences Inc. 0 November 7, 2008 HWA Project No. 2007-080-21 T1200 The soil units encountered in this boring are described below, with materials interpreted as being youngest in origin and nearest the surface described first. • ACP Surfacing— ACP (asphaltic concrete pavement) was encountered at the surface at 13H-6, where it was 0.33 feet (4 inches). • Road Base — Immediately beneath the existing ACP surfacing, roadway fill consisting of very dense, gray, gravel with sand was encountered. Apparently, this material was placed prior to paving NE Lyons Avenue. The road base aggregate at this location was about 0.66 feet (8 inches) in thickness. • Fill — Immediately beneath the existing road base in 131-1-6, fill consisting of dense, olive gray to brown, gravelly, silty sand was encountered. Apparently, this material was placed during construction of NE Lyons Avenue. The fill was about 3.0 feet thick at this location. • Weathered Till — Immediately beneath the existing road base in 131-1-6, weathered till consisting of dense, olive gray, silty, fine to medium sand with gravel was encountered. This material represents native glacial till soil that was subject to weathering prior to the construction of NE Lyons Avenue. The weathered till at the location of 131-1-6 was about 3.0 feet in thickness. This soil will provide adequate bearing for a sewer pipeline. Vashon Till — In general, native glacial till, consisting of dense to very dense, gray, silty sand with gravel to silty gravel with sand, was encountered in the 131-1-6 beneath the layer of weathered till, and constitutes the deepest local native soil unit encountered during drilling at this location, where it was in excess of 13.5 feet thick and not fully penetrated. This soil will provide excellent bearing for a sewer pipeline. 3.3.4 147th Avenue SE (BH-7) This location is along the originally proposed force main alignment east of where the force main would have to cross an unnamed creek in the local valley bottom, situated near the southern terminus of 147`h Avenue NE. The approximate location of this boring is shown on Figure 3E. At this location, 131-1-7 was conducted with closely spaced (2.5 foot) sampling intervals in the upper 15-16.5 feet, and more widely spaced (5 foot) intervals once the boring encountered very dense native soil, to characterize the engineering properties of the local subsoils and attempt to detect local ground water seepage. In general, the NE Lyons Avenue location is underlain by native subsoil, predominately consisting of very dense glacial till soils that locally are overlain by medium dense weathered till and native fills of varying thickness. 131-1-7 was conducted to a final depth of 21.5 feet below the existing ground surface. Ground water seepage was observed at an approximate depth of 10 feet below the existing ground surface while conducting boring 131-1-7 on 147`h Avenue NE. 131-1-7 was completed as a standpipe piezometer to allow for ground water level monitoring during the upcoming wet weather season. Stonegate 11 Final Geotech Report.doc 7 HWA GeoSciences Inc. November 7, 2008 HWA Project No. 2007-080-21 T1200 The soil units encountered in this boring are described below, with materials interpreted as being youngest in origin and nearest the surface described first. • Road Base — Immediately at the ground surface, roadway fill consisting of medium dense, olive gray, fine, sandy gravel was encountered. This material was placed as the trafficking course along this road. At this location, the road base was about 0.75 feet (9 inches) thick. Alluvium — Immediately beneath the existing road base in BH-7, disturbed to medium dense/stiff alluvial soil consisting of olive brown to gray, clean to silty, fine sand with some scattered fine gravel to silt with sand was encountered. This material appears to represent native alluvial soil deposited by local fluvial processes. The alluvium at the location of BH-7 was about 11.3 feet in thickness. This soil will provide adequate bearing for a sewer pipeline. • Glacial Outwash — Beneath the alluvium, a layer of native glacial outwash, consisting of dense, olive brown to gray, silt with sand and gravel to gravelly silty sand was encountered in BH-7, and constitutes the deepest local native soil unit encountered during drilling at this location, where it was in excess of 9.0 feet thick and not fully penetrated. ' 3.3.5 148th Avenue SE (BH-8) This location is along the originally proposed force main alignment east of where the force main would have turned west to traverse down slope toward the valley incised by the unnamed creek along the west shoulder of 1481h Avenue NE. The approximate location of this boring is shown on Figure 3F. At this location, BH-8 was conducted with closely spaced (2.5 foot) sampling intervals in the upper 15-16.5 feet, and more widely spaced (5 foot) intervals once the boring encountered very dense native soil, to characterize the engineering properties of the local subsoils and attempt to detect local ground water seepage. In general, the 1461h Avenue NE location is underlain by native subsoil, predominately consisting of very dense glacial till soils that locally are overlain by medium dense weathered till and native fills of varying thickness. BH-8 was conducted to a final depth of 31.5 feet below the existing ground surface. Ground water seepage was observed while conducting boring BH-8 on 1481h Avenue NE. Perched ground water seepage was observed at depth of 23 to 28 feet. Seepage appeared to be carried by a relatively clean sand seam within the till. The soil units encountered in this boring are described below, with materials interpreted as being youngest in origin and nearest the surface described first. • ACP Surfacing — ACP (asphaltic concrete pavement) was encountered at the surface at BH-8, where it was about 0.66 feet (8 inches). Road Fill — Immediately beneath the existing ACP surfacing, roadway fill consisting of loose, brown, silty sand with gravel was encountered. Apparently, this material was placed Stonegate II Final Geotech Report.doc 8 HWA GeoSciences Inc. November 7, 2008 HWA Project No. 2007-080-21 T1200 prior to paving 1481h Avenue NE. The road fill at this location was about 1.33 feet (16 inches) thick. Weathered Till — Immediately beneath the existing road fill in BH-8, weathered till ' consisting of medium dense, light brown, silty fine sand with gravel was encountered. This material represents native glacial till soil that was subject to weathering prior to the construction of 1481h Avenue NE. The weathered till at the location of BH-8 was about 3.0 feet thick. 1 Vashon Till — In general, native glacial till, consisting of medium dense to very dense, olive brown to gray, silty sand with gravel, was encountered in the BH-8 beneath the layer of weathered till, and constitutes the deepest local native soil unit encountered during drilling at this location, where it was in excess of 25.25 feet thick and not fully penetrated. Locally, the till contains clean sand seams which, if saturated, can drain when encountered in excavations. 3.3.6 Stonegate-Summerwind Connector (131-1-9 & BH-10) These borings were conducted to explore the subsurface conditions along the route proposed to connect the wet well at the existing Summerwind lift station (131-1-9) with the Stonegate gravity sewer system in NE 241h Court (131-1-10) as shown on Figure 4. At the wet well location, BH-9 was conducted with closely spaced (2.5 foot) sampling intervals in the upper 10-11.5 feet, and more widely spaced (5 foot) intervals once the boring encountered very dense native soil, to characterize the engineering properties of the local subsoils and attempt to detect local ground water seepage. In general, BH-9 encountered native subsoil below a depth of approximately 13.5 feet, predominately consisting of very dense glacial till soils that locally are overlain by fill placed during the construction of the detention pond, consisting of medium dense, silty sands of probable local origin. BH-9 was drilled to a depth of approximately 31 feet below the existing ground surface. Minor perched ground water seepage was observed above the contact between the fill and glacial till while conducting boring BH-9. BH-9 was completed as a standpipe piezometer to allow for ground water level monitoring during the upcoming wet weather season. BH-10 was conducted adjacent to the existing manhole situated in NE 24`h Court, where the connection with the existing Stonegate gravity system will be made. At this location, the upper 7 feet was explored using a Vactor truck in order to avoid utility damage. Below 7 feet, closely spaced sampling, consisting of 2.5 foot intervals to a final depth 20.5 feet, was performed. In general, BH-10 encountered native subsoil below a depth of approximately 12.5 feet, predominately consisting of very dense glacial till soils that locally are overlain by fill, placed during the installation of the manhole and roadway, consisting of medium dense silty sand to sandy silt of probable local origin. No ground water seepage was observed well conducting BH-10 at NE 24`h Court. Stonegate II Final Geotech Report.doc 9 HWA GeoSciences Inc. November 7, 2008 HWA Project No. 2007-080-21 T1200 The soil units encountered in these borings are described below, with materials interpreted as being youngest in origin and nearest the surface described first. ACP Surfacing — ACP (asphaltic concrete pavement) was encountered at the surface at BH-10, where it was 0.25 feet (3 inches) thick and underlain by additional 0.25 feet (3 inches) of well compacted crushed rock base. • Pond Fill — At the surface in BH-9, fill consisting of medium dense, gray to olive brown, silty sand that contained wood pieces and minor amounts of organic debris was encountered. Apparently, this material was placed during construction of the Summerwind detention pond adjacent to the existing lift station. The fill was about 13.5 feet thick at this location. Construction Fill — Immediately beneath the existing road base in BH-10, construction fill consisting of loose to medium dense, gray brown mottled, silty sand to sandy silt with gravel and some cobbles was encountered. The lowermost 2.5 feet of this fill appeared to consist of gravel placed as bedding material beneath the manhole structure. This material represents backfill placed around the manhole. The construction fill at location of BH-10 was about 12.0 feet thick. Vashon Till — In general, native glacial till, consisting of dense to very dense, gray, silty sand with gravel to silty gravel with sand, was encountered in both BH-9 and BH-10, beneath the local layers of fill, and constitutes the deepest local native soil unit encountered during drilling at these locations, where it was in excess of 11.5 and 17 feet thick, respectively, and not fully penetrated. This soil will provide excellent bearing for a connecting pipeline. Piping may be installed using open cut or directional drilling methods. If directional drilling is preferred, we recommend additional exploration along the route in an attempt to assess the potential presence of boulders. Alternatively, open -cut methods, if practical in terms of design invert elevation, should work reasonably well. 3.3.7 NE 261h Street Culvert Under -crossing (BH-13 & BH-14) These borings were conducted to explore the subsurface conditions along the route of the new force main proposed to connect the new Stonegate II lift station with the existing Summerwind gravity sewer system at NE 201h Street, as shown on Figure 5C. At this location along NE 26`h Street, the planned force main must pass beneath a culvert that crosses the road conveying stream flow from an unnamed creek to the wetlands associated with May Creek. Borings BH-13 and BH-14 were conducted at the downstream and to the east, and the downstream and to the west of, the culvert, respectively. Both Borings were conducted to final depths of 31.5 feet, with closely spaced sampling (2.5 foot intervals) in the upper 15-25 feet, and more widely spaced (5 foot) intervals once the borings encountered medium dense native glacial soils, to characterize the engineering properties of the local subsoils and attempt to detect local ground water seepage. In general, BH-13 encountered native subsoil below a depth of approximately 7.5 feet, Stonegate 11 Final Geotech Report.doc 10 HWA GeoSciences Inc. P_J ' November 7, 2008 HWA Project No. 2007-080-21 T1200 1 predominately consisting of medium dense alluvial silty sand that locally is overlain by imported fill, placed during the construction of the road and culvert, consisting of medium dense, gravelly sand to sandy gravel. BH-14 encountered native subsoil below a depth of approximately 5 feet, predominately consisting of medium dense alluvial silty sand that locally is overlain by imported ' fill, placed during the construction of the road and culvert, consisting of medium dense gravelly sand to sandy gravel. Ground water seepage was observed within the alluvial soils in both borings at an approximate depth of 15 feet below the existing ground surface. BH-13 was ' completed as a standpipe piezometer to allow for ground water level monitoring during the upcoming wet weather season. I The soil units encountered in these borings are described below, with materials interpreted as being youngest in origin and nearest the surface described first. ' • ACP Surfacing — ACP (asphaltic concrete pavement) was encountered at the surface at BH-13 and BH-14, where it was 0.25 to 0.33feet (3-4 inches) thick and underlain by an additional 1.25 to 3.2 feet (15-38 inches) of compacted sandy gravel base. Beneath the ' gravel base at both locations, a 6 inch layer of recycled asphaltic pavement (RAP) was encountered that was probably placed as backfill during installation of the existing culvert. ' • Alluvium — Immediately beneath the layer of RAP in both borings, a layer of alluvial soil consisting of medium dense, light brown, silty fine sand with some scattered fine gravel was encountered. Locally, the deposit contains thin interbeds of stiff silt. This material appears to represent native alluvial soil deposited by local fluvial processes. The thickness of alluvium at the locations of BH-13 and 14 was about 26 and 24.5 feet, respectively. ' Typically, this soil is suitable as foundation of non -critical, lightly loaded, structures, due to low strength, increased settlement potential, and susceptibility to liquefaction. However, we expect these hazards will have less potential impact on a forcemain. The piping may be installed using open -cut or directional drilling methods. Dewatering may be required in either case, depending upon the relationship of planned pipe invert elevation and local ground water levels to limit incursion into trenches or jacking pits. ' • Recessional Lacustrine — Beneath the recessional outwash sand and gravel layer in BH-11, a layer of stiff clayey sand to sandy clay was encountered at an approximate depth of 30 feet ' and was in excess of 16.5 feet thick. In BH-12, recessional lacustrine material was encountered, between two layers of recessional outwash, at a depth of 22 feet and was 8 feet thick (i.e. between 22 and 30 feet BGS). This material appears to represent native fine ' grained glacial lacustrine deposits that formed within lakes created by temporary dams within or marginal to the outwash channel. Stonegate II Final Geotech Report.doc 11 HWA GeoSciences Inc. November 7, 2008 HWA Project No. 2007-080-21 T1200 3.3.8 Proposed Stonegate II Lift Station (BH-11 & BH-12 ' Two borings were conducted to explore the subsurface conditions at the location proposed for the new Stonegate II Lift Station. The new lift station is planned to be constructed north of the existing lift station located near the corner of NE 26`h Street and 148`h Avenue NE, as shown on Figure 5B. According to Roth Hill, the invert of the wetwell/overflow structure will be about 26.5 feet below existing grade. At both locations, the borings were conducted with closely spaced (2.5 foot) sampling intervals in the upper 10-11.5 feet, and more widely spaced (5 foot) ' intervals once the boring encountered medium dense native soil, to characterize the engineering properties of the local subsoils and attempt to detect local ground water seepage. In general, both borings encountered a thin layer of alluvial soils overlying recessional outwash and ' recessional lacustrine soils. The alluvial soils encountered range from 3.5 to 8.5 feet in thickness, and predominantly consist of medium dense sands and gravels with varying amounts ' of silt and trace cobbles. Below the alluvium, recessional outwash consisting of medium dense, saturated, sand and gravel with variable silt content; and recessional lacustrine deposits, consisting of silt and clay with occasional sand interbeds, were encountered. Borings BH-I I and ' BH-12 were both terminated 41.5 feet below the existing ground surface, in glacial recessional lacustrine or outwash soils. Ground water seepage was observed in both borings at an approximate depth of 7.5 feet below the existing ground surface. BH-I I was completed as a ' standpipe piezometer to allow for ground water level monitoring during the upcoming wet weather season. ' The soil units encountered in these borings are described below, with materials interpreted as being youngest in origin and nearest the surface described first. t • Topsoil — Immediately at the ground surface, topsoil consisting of loose, dark brown, silty fine sand was encountered. The topsoil layer ranged from 2 to 2.5 feet thick. ' • Alluvium — Immediately beneath the topsoil in both borings, a layer of medium dense/stiff alluvial soil consisting of olive brown to gray, clean to silty, fine sand with some scattered fine gravel to gravel with silt and sand was encountered. This material appears to represent ' native alluvial soil deposited by local fluvial processes. The thickness of alluvium at the locations of BH-I I and 12 were about 3.5 and 8.5 feet, respectively. Typically, this soil is suitable as foundation of non -critical, lightly loaded structures, due to low strength, increased ' settlement potential, and susceptibility to liquefaction. • Recessional Outwash — Beneath the alluvium, a layer of native glacial outwash, consisting ' of primarily medium dense, gray, olive brown to gray, silt with sand and gravel to gravelly silty sand, was encountered in the BH-I I and BH-12. This material appears to represent native glacial outwash soil deposited by melt water from the receding glacial front. The Stonegate II Final Geotech Report.doc 12 HWA GeoSciences Inc. 1 November 7, 2008 HWA Project No. 2007-080-21 T1200 thickness of outwash at the location of BH-I I was 19 feet. In BH-12, recessional outwash deposits appeared to be encountered below the alluvium at depths of between 9.5 to 22 feet, and again below a layer of recessional lacustrine deposits at an approximate depth of 30 feet below the existing ground surface. This soil should serve as an adequate foundation for the wet well. • Recessional Lacustrine — Beneath the recessional outwash sand and gravel layer in BH-11, a layer of stiff clayey sand to sandy clay was encountered at an approximate depth of 30 feet and was in excess of 16.5 feet thick. In BH-12, recessional lacustrine material was encountered between two layers of recessional outwash at a depth of 22 feet and was 8 feet thick (i.e. between 22 and 30 feet BGS). This material appears to represent native fine grained glacial lacustrine deposits that formed within lakes created by temporary dams within. or marginal to the outwash channel. This material will provide an adequate foundation for the wetwell. 3.3.9 Summary of Soil Conditions To assist with an understanding of the soil conditions encountered at each of the investigated sites, we have compiled a tabulated summary of the various units, as indicated in Table 1. Stonegate 11 Final Geotech Report.doc 13 HWA GeoSciences Inc. November 7, 2008 HWA Project No. 2007-080-21 T1200 Table 1: Summary of Explored Soil Conditions Approximate Anticipated Native Soil: Anticipated Trench Fill or Project Stationing Vertical Succession Native Soil Conditions (top down) NE Field Avenue (Alignment from South to North ) Medium dense to loose, silty From Station:2+00' Fill=>Vashon Till gravelly SAND(trench)-Dense to to 1 1+30' very dense, silty SAND with gravel (native) 201h Street NE Station: 18+30' Fi11=:>Weathered Till=>Vashon Medium dense to very dense, silty Till SAND with gravel, moist. Stonegate - Summerwind Connector zDike east -of existing Fi11=>Vashon Till Medium dense to very dense, silty lift Station SAND with gravel z West of manhole in Fi11�Vashon Till Medium dense to very dense, silty NE 241h Place SAND with gravel. NE 26th Street Culvert Crossing At existing culvert crossing: Station Fill=>Alluvium=>Recessional Medium dense, silty SAND with 26+04' Lacustrine gravel over stiff, lean CLAY. New Stonegate II Lift Station North of existing FiI1=>Alluvium=>Recessional Medium dense to dense, gravelly Stonegate Lift Station Outwash and Lacustrine SAND to silty GRAVEL over stiff, lean CLAY Stonegate II Final Geotech Report.doc 14 HWA GeoSciences Inc. ' November 7, 2008 HWA Project No. 2007-080-21 T1200 4.0 RECOMMENDATIONS 4.1GENERAL The following is a summary of our conclusions and recommendations based on the soil and ground water conditions encountered in our explorations: • Temporary excavations for the lift station should be supported with a relatively ' water -tight shoring system, such as interlocking steel sheet piles. Internally -braced shoring is recommended. The contractor should be responsible to design and ' install the temporary shoring. • The lift station excavation will extend approximately 20 feet below ground water; therefore, construction dewatering will be required. Dewatering should be undertaken from the inside of the shoring system, to reduce the potential for settlement of the surrounding infrastructure. Driven interlocking sheet piling, ' extending down to the glacial lacustrine layer, will tend to act as a seal and will substantially reduce ground water flows into the excavation. Temporary excavation support recommendations are presented in Section 4.2.1. ' • Upsizing/replacement of the gravity sewer along NE Field Avenue can be undertaken by either open trenching or pipe -bursting, as described in Sections 4.3 ' and 4.4 below. • Dewatering will be required for the HDD or pipe jacking pits,. or if the culvert ' under -crossing along NE 261h Street is undertaken using open -cut methods. Sumps and pumps may be adequate in some locations; however, where the proposed sewer invert extends significantly below the ground water level, dewatering wells or well ' points will be required. Dewatering should be confined to the immediate area of the trench to limit the potentially adverse effects of ground water drawdown on adjacent properties. ' 4.2 STONEGATE II LIFT STATION ' 4.2.1 Temporary Shoring We understand the new lift station will require an approximately 27-foot deep temporary ' excavation. The excavation will extend about 20 feet below the existing ground water level. We recommend a relatively water -tight shoring system, such as interlocking steel sheet piles, be used. ' The principal advantage of steel sheet piles over soldier piles and wood lagging is that construction dewatering may be accomplished from within the shoring, without significantly Stonegate 11 Final Geotech Report.doc 15 HWA GeoSciences Inc. i November 7, 2008 HWA Project No. 2007-080-21 T1200 lowering the ground water outside the shoring. The high permeability of soldier pile and lagging shoring would require construction dewatering on the outside of the excavation. Because of the proximity of the new lift station structure to the private property to the east and the existing paved parking lot, dewatering induced settlement of the surrounding infrastructure should be avoided. Recommended design earth pressures for temporary braced shoring are presented in Figure 6. ' The contractor should be responsible for the temporary shoring system design. Successful installation and removal of the temporary shoring system is the responsibility of the contractor. ' It may be somewhat difficult to drive the sheet piles through the existing dense glacial drift underlying the lift station site. Therefore, we recommend sheet piling with a minimum web thickness of `/2-inch be used. Sheet piling sections with a thinner web thickness are prone to ' installation damage when driving through dense sand and gravel. A large vibratory hammer should be used to install the steel sheets, to ensure the required penetration is achieved. Alternatively, thinner sheets might be used if the shoring alignment is predrilled to loosen the deposits in advance of driving of the sheets. It will be the contractor's responsibility to select the appropriate sheet piling and vibratory hammer for the job. The sheet piling may be extracted or cut below ground surface and left in place when the lift station construction is completed and backfilled. 4.2.2 Ground Water Control / Dewatering Construction dewatering should be accomplished from within the relatively water -tight shoring system, to limit drawdown exterior to the shoring. Silty to clayey glacial lacustrine soils, consisting of stiff to very stiff sandy silt to clay, exists below 25 feet. This material has a much lower permeability that the overlying clean to slightly silty sand and gravel. Driving sheet piles into these fine-grained materials will cut-off ground water and substantially reduce flows into the excavation. One method of controlling ground water would be to drive the steel sheets down and into the lacustrine layer, excavate in the wet to subgrade elevation, and then tremie-pour a concrete slab ("mud -slab"). Once the concrete has cured, the water above the mud slab could be pumped out of the excavation. As a general and conservative rule of thumb, the thickness of the mud slab should be approximately 40% of the ground water displacement depth. In this case, for ground water approximately 6 feet below ground surface and the bottom of the overflow storage wet well about 27 feet below ground surface, the thickness of the mud slab should be about 8% feet. Leakage through joints in the steel sheets and along the mud slab/sheet pile interface may be handled by using suitably sized sumps and trash pumps. 1 Stonegate 11 Final Geotech Report.doc 16 HWA GeoSciences Inc. ' November 7, 2008 HWA Project No. 2007-080-21 T1200 Alternatively, dewatering wells could be installed on the inside of the shoring. The effectiveness ' of the dewatering wells will depend on whether the sheet piles are keyed into the silt/clay layer. The contractor should retain a dewatering specialist to design and operate the dewatering system. 4.2.3 Lift Station Excavation Excavations for the lift station can be completed with conventional excavating equipment, such ' as trackhoes. Although not encountered in our borings, there is a potential for logs to exist within the alluvial deposits. The contract should, therefore, contain provisions for excavating and dealing with oversize woody materials. t4.2.4 Buoyancy As with other manhole structures, the lift station will need to be designed to resist hydraulic buoyancy. Recommended parameters for calculating uplift resistance are presented in Figure 5. We recommend the ground water be assumed to be at the ground surface for buoyancy resistance design calculations. 4.3 PIPE BURSTING Pipe bursting may be an economically feasible alternative to conventional open -cut trench and pipe replacement methods due to the potentially timesaving, cost effective, and less disruptive methodology inherent in the procedure. We understand that pipe bursting is being considered for use during upsizing of the gravity conveyance system along the NE Field Avenue, where traffic and pavement disruptions due to construction are to be minimized. Connections to existing side sewers will, however, still require localized open cuts for access. The pipe bursting process consists of in -situ fragmentation, displacement, and replacement of the existing pipes with new polyethylene pipes of equal or larger diameter. Typically, the existing pipe is split by a hydraulic or pneumatic bursting -head or nosecone to which the new polyethylene pipe is attached. As the existing pipe is burst, the new polyethylene pipe is pulled along the alignment of the old pipe. A chain or cable towline attached to a hydraulic jacking or winch system is used to advance the bursting head. Typically, the polyethylene pipe installed during the pipe bursting process consists of 20 to 40 foot sections that are welded together on site. Pipe bursting is conducted between two points of access; i.e., station —to -station with stations consisting of existing manholes, or insertion and extraction pits. We understand that the existing pipes (8 inches in diameter) will be up -sized to 12 inches, to handle the future sewage flows. Typically, the most common type of pipe bursting is size -for - size; however, upsizing the diameter up to three sizes (e.g. 8-inch to 12-inch) is fairly routine (TTC, 2001). 1 Stonegate II Final Geotech Report.doc 17 HWA GeoSciences Inc. ' November 7, 2008 HWA Project No. 2007-080-21 T1200 For pipe bursting to be successful, information regarding the density of the existing soil backfill ' and adjoining native materials is required. Accordingly, during our exploration program, several of our borings were conducted within the existing sewer trenches in order to characterize the engineering properties of the existing trench backfill. The results of our borings indicate that the ' backfill in the vicinity of the existing pipes along NE Field Avenue is generally loose to medium dense, which is a condition generally conducive to a pipe bursting operation. ' Information regarding the proximity of other service lines or underground structures, and the location of any documented prior service repairs that reinforce the existing pipe should be evaluated. Such information is utilized to select the most appropriate pipe bursting methods and ' tools, and to evaluate the potential effects of vibrations and ground displacements, associated with the bursting operations. Studies have shown that the vibrations caused by pipe bursting tend to have a frequency range well above the natural frequency of buildings (TTC, 2001). However, in areas of concern or at the beginning of the project, we recommend that vibration monitoring be conducted to verify that pipe bursting efforts are not generating damaging levels of ground vibration. In general, pipe bursting should not be used when the bursting head will ' pass within 2.5 feet of other buried pipes and within 8 feet of sensitive surface structures (TTC, 2001). Where distances are less than those mentioned above, special provision should be made ' to protect the existing structures, such as excavating (daylighting) at the crossing point to relieve potential induced -stress on the existing pipe (TTC, 2001). ' Favorable ground conditions for pipe bursting are reportedly within soils that can be moderately compacted such that the enlarged hole behind the bursting head does not cave in before the replacement pipe is installed. This scenario results in minimal lateral extent of outward ground ' movement because the volume change is accommodated by the local soils. In addition, the lack of caving behind the bursting head will result in lower drag and reduced tensile stress on the pipe during installation (TTC, 2001). Less favorable ground conditions include densely compacted soils or fills, and soils below the water table. These ground conditions tend to increase the force required for the bursting operation. ' Our borings indicate that the backfill in the vicinity of the existing pipe is relatively loose. It is our opinion, therefore, that pipe upsizing by means of pipe bursting is feasible along NE Field Avenue. However, the contractor should anticipate that variation in local fill soil conditions, and ' the presence or absence of ground water, will affect the amount of force required to burst and pull replacement pipe. Some ground displacement should be expected as a result of a pipe bursting procedure. Displacements tend to be localized, and develop in the direction of least resistance. The magnitude and orientation of the displaced soil is largely dependent upon the degree of pipe upsizing, the type and compaction level of the soil surrounding the pipe, and the depth of the pipe. Typically, loose soils will undergo uniform displacement where more densely compacted soils at the same depth will most likely exhibit vertical (heave) expansion. The localized Stonegate II Final Geotech Report.doc 18 HWA GeoSciences Inc. ' November 7, 2008 HWA Project No. 2007-080-21 T1200 restraining effect of strong soils along trench sides and bottom also serves to direct ground ' movement upward above the pipe. Conversely, if the existing pipes were founded on weak soil, displacement would be directed downward. . I We understand that some of the existing pipes along the project alignment are as shallow as 5 feet below the existing ground surface. Pipe bursting conducted on pipes shallower than 8 to10 feet may cause ground movement (heaving) that may distort the existing road surface. We recommend that some contingency provision be made to accommodate the rehabilitation of the existing road surface where pipes are shallow and surface heaving results. Bursting of pipes located deeper than 10 feet does not typically cause surface heaving problems. Invariably, some surface disturbance along the existing alignment is necessary for the excavation of jacking/receiving pits. These excavations can require an area on the order of 16 feet by 8 feet. Side sewers, however, can be installed from a pit as small as 6 by 4 feet. Service connections to the pipeline being burst are typically dug prior to bursting so that the connections are not damaged and temporary bypass service can be provided during construction. These excavations can induce localized upward movement of the replacement pipe as it passes the area creating a slight hump in the pipeline profile. This problem can be minimized by excavating beneath the pipe, as well as above the pipe at the service connection location (TTC, 2001). As with any gravity system, maintaining the established grade is very important. As previously described, the replacement pipe follows the alignment of the original pipe under most conditions. However, because the bursting head has a larger diameter than the replacement pipe, a cavity is developed in the soil, allowing the replacement pipe to take up different positions within the cavity. Depending upon the local soil conditions, site conditions, and installation procedures the following outcomes are anticipated: 1. If soil displacements are predominately upward, a larger new pipe will most likely be situated with its centerline higher than the original pipe, but with a matching invert elevation. 2. If the soil displaces uniformly, the larger new pipe will be match the centerline of the original pipe. If the soil displacements are predominately downward, the larger new pipe will most likely be situated with its crown matching the original pipe crown position, but with a lower invert elevation. 4. Asymmetrical soil displacement, resulting from the restraining effects of adjacent buried structures, can result in a lateral shift in new pipe position relative to the original. Case histories suggest that, with careful planning, maintenance of the existing pipe grades is achievable when close attention and frequent surveys are conducted. Sometimes, the presence of unforeseen large boulders, and existing concrete pipe collars, CDF backfill, adjacent utilities and Stonegate 11 Final Geotech Report.doc 19 HWA GeoSciences Inc. C November 7, 2008 HWA Project No. 2007-080-21 T1200 such, will prevent the advancement of the pipe bursting head or cause it to deflect above or below the design invert level. These types of obstructions occur quite commonly despite the amount of available subsurface data and/or as -built and maintenance records, and it is recommended that contingencies be provided in the contract to deal with such problems if they occur. 4.4 HORIZONTAL DIRECTIONAL DRILLING The use of horizontal directional drilling (HDD) methods may be appropriate for use in constructing the connector between the wet well at the existing Summerwind lift station and the Stonegate gravity system in NE 241h Court (See Figure 3), and the culvert under -crossing required for the new force main alignment where it encounters a culvert on NE 26`h Street (See Figure 4C). The Summerwind-Stonegate connector would likely be constructed by installing an 8-12-inch OD HDPE pipe through the existing fill or native soils that overlie very dense native glacial till. The connection is planned between the wet well at the Summerwind lift station and the existing sanitary sewer manhole in NE 24`h Court; a horizontal distance of roughly 200 feet. We understand that a narrow easement exists through this area which is situated along a property line between two adjacent residential structures. Constructing a new pipeline along this alignment using HDD will eliminate the need for open cuts, backfilling, dewatering and landscaping repair; thereby, minimizing the potential impact to the existing private property. The culvert under crossing along NE 26`h Street involves installing an 8-12-inch OD HDPE pipe through medium dense silty sand with gravel, beneath a culvert that is approximately 4.5 feet high and 5.7 feet wide and with an invert elevation that is approximately 6-7 feet below the existing road surface elevation. Constructing the new force main along this portion of the alignment using HDD will eliminate the need for open cuts, culvert replacement, backfilling, dewatering and pavement repair. HDD is a trenchless methodology that involves drilling a small pilot hole, using technology that allows the drill to be steered and tracked from the surface. The pilot hole is launched from the surface at an angle, typically between 8 to 18 degrees to the horizontal, then transitioning to horizontal as the required depth is reached. A bore path with a very gradual curvature or near straight alignment is normally followed to minimize friction and to stay within the allowable joint deflection and curve radius for the pipe. The pilot hole is enlarged by pulling back increasingly larger reamers from the pipe insertion point (the recovery pit) to the rig side (entry pit) until the hole is approximately 1.5 times the outside diameter of the new pipe. On the final reamer pass, the new pipe is pulled behind the reamer back through the HDD path to the entry pit on the rig side. Stonegate II Final Geotech Report.doc 20 HWA GeoSciences Inc. ' November 7, 2008 HWA Project No. 2007-080-21 T1200 Because minimization of disturbance to the roadway prism is a key project objective, ' consideration should be given to the utilization of this method for the pipeline marsh crossing. Items due consideration and that may be of concern are: ' • Location of all utilities along the alignment: All utilities within 20 feet of the proposed bore path in three dimensions. ' • Location of buried structures along the route. The HDD pipeline would extend below the existing culvert crossing. ' • The ability of the drill string to accommodate the required radius of curvature. Usually the drill string requires a larger radius than the pipe. The radius is controlled by the position of the entry and exit points and the entry angle. ' • If HDD is selected, additional borings should be drilled to explore and define the vertical and lateral limits of the fill/glacial soil contact along to the proposed Summerwind - ' Stonegate Connector alignment. 4.5 OPEN CUT TRENCHING ' Presently, open -cut trenching methods are planned for the installation of the force main required to convey effluent from the new Stonegete II lift station to the tie-in location with the existing ' Summerwind gravity system along NE 20`h Street. Open -cut trenching techniques may also used in support of pipe bursting to allow for the construction of insertion pits, service tie-ins, manholes, etc. The following sections describe the methodology and outline our ' recommendations for excavation, shoring, dewatering, pipe placement and trench backfilling. 4.5.1 Soil Excavation Characteristics ' Excavations for the pipelines can be accomplished with conventional excavation equipment such as backhoes and trackhoes. ' 4.5.2 Sloped Open -Cut Excavations ' Maintenance of safe working conditions, including temporary excavation wall stability, should be the responsibility of the contractor. All temporary cuts in excess of 4 feet in height should be sloped to accordance with Part N of WAC (Washington Administrative Code) 296-155, or should be temporarily shored. The fill, alluvial, and weathered till deposits generally classify as Type C soil, per WAC 296-155, and should be sloped no steeper than l%H:IV (horizontal: vertical). The glacial till soils in the project area generally classify as Type A soil, ' and should be sloped no steeper than 3/4H:1 V. These recommended allowable cut slope inclinations are applicable to excavations above the water table only, and for conditions where seepage is not occurring. Dewatering or flatter cut slopes will be required where ground water Stonegate II Final Geotech Report.doc 21 HWA GeoSciences Inc. November 7, 2008 HWA Project No. 2007-080-21 T1200 seepage is encountered. Additionally, excavation spoil and fill materials should not be stockpiled nearer than the depth of excavation from the excavation slope crest for these recommendations to remain applicable. Vibrations created by traffic and construction equipment may cause some caving and raveling of excavation walls, especially in sands and gravels. If this occurs (including excavations shallower than 4 feet), temporary lateral support for the excavation walls should be provided by the contractor to prevent loss of ground support, as required. 4.3.1 Shored Excavations Where space or ground water conditions do not permit sloped excavations, lateral support for the trench walls should be provided by the contractor to ensure adequate worker safety and prevent loss of ground and possible distress to the nearby services or roads. General recommendations for design and implementation of shoring and bracing systems are presented below. Recommended lateral earth pressure diagrams for temporary braced shoring are presented on Figure 6. However, the contractor should be responsible for the design and maintenance of all temporary bracing, as the design is often influenced by the contractor's operations. Shoring should be designed and constructed to support lateral loads exerted by the supported soil mass. In addition, any surcharge from construction equipment, construction materials, excavated soils, or vehicular traffic on adjacent roadways should be included in the shoring design. We recommend that the contractor be required to submit shoring/excavation plans for review and approval prior to construction. The plans should be required to contain specific measures for temporary support and protection of the existing utilities and structures. Conventional trench boxes should provide suitable worker safety for trench excavations in fill, alluvial sands and gravels, outwash and till soils provided the ground water level is lowered to at least 2 feet below the base of the excavation, and settlement sensitive structures or utilities are not situated near the excavation. Where a trench box is used to provide for worker safety in an excavation in the fill or recessional outwash soils, one or both sides of the trench walls are likely to deflect and possibly cave against the box. The caving may extend out on either or both sides of the trench for a distance approximately equal to the depth of the trench. This potential for yielding and caving of trench walls and loss of adjoining soils should be taken into account with regard to the integrity of the roadway and adjoining services/properties. For the jacking/insertion pits required for trenchless installation methods, soldier piles and lagging may be suitable, depending on the conditions and equipment used by the contractor. Jacking pits will likely require internal bracing. The recommended lateral pressures for the design of temporary shoring of such pits are also provided on Figure 18, Stonegate II Final Geotech Report.doc 22 HWA GeoSciences Inc. ' November 7, 2008 HWA Project No. 2007-080-21 T1200 but the contractor should be responsible for appropriate design of the pit shoring ' consistent with his needs and public safety and property protection requirements. • The contractor should be responsible for control of ground and surface water and should ' employ sloping, slope protection, ditching, sumps, dewatering, and other measures as necessary to prevent sloughing of soils. ' • Precautions should be taken during removal of the shoring to minimize disturbance of the pipe, underlying bedding materials, and native soils. ' 4.3.2 Ground Water and Construction Dewatering It should be the responsibility of the contractor to provide dewatering of trench excavations to ' maintain sufficiently dry conditions during construction. The ground water levels and seepage conditions reported on the exploration logs in Appendix A, may be used for preliminary dewatering design and estimating purposes. Although, most of the explorations encountered ' little or no ground water within the proposed trench base elevations, the contractor should field -verify actual ground water conditions encountered during construction and adjust dewatering requirements/methods as appropriate. ' In general, low to moderate ground water seepage can be expected in trenches excavated in alluvial soils and dewatering can likely be accomplished in these soils using sumps, as required. ' However, rapid ground water seepage can be expected in trenches excavated below the ground water table in outwash soils. We recommend the use of wells or well points to draw the water table down in advance of trench excavation and reduce seepage inflows into trenches within ' outwash soils, as appropriate. Because the trench subgrade may be at or near the interface with the less permeable glacial till soils, in some instances, sumps may be required in addition to wells in order to collect seepage at the trench bottoms. We recommend HWA review the dewatering plans and specifications, if included in the bid documents. Alternatively, HWA is available to assist in design of a dewatering plan. ' 4.3.3 Pipeline and Manhole Settlement ' Typically, sewer installations result in little to no change in effective loading of underlying foundation soils. However, settlement of trench backfill is commonplace and occasionally settlements also occur in the pipe installations. Where such settlements are encountered in ' pipeline components in the absence of load changes to the foundation soils, it is usually associated with disturbance to the trench base and/or poor compaction in the pipe bedding and pipe zone backfill soils. Therefore, it is imperative that good construction practices be employed ' in pipeline trench excavation and preparation of the trench base, bedding and pipe zone backfill to prevent unacceptable deformations in the completed pipelines. If good construction practices Stonegate II Final Geotech Report.doc 23 HWA GeoSciences Inc. E 1 November 7, 2008 HWA Project No. 2007-080-21 T1200 are employed, we expect that post -construction total and differential settlements will be negligible to small and acceptable. 4.3.4 Pipeline Support and Bedding Based on our field explorations, we anticipate subgrade conditions generally adequate for pipe support at proposed pipe invert elevations. General recommendations for the support of the proposed pipelines are presented below: Excavation of the trench subgrade should be undertaken to design depth with care to minimize disturbance to the subgrade and reduction of soil support. Where loose material results from the excavation operations, it should be removed or recompacted to provide for a smooth and unyielding surface. In the event very soft subgrade soils are encountered, it may be necessary to over -excavate the unsuitable material and backfill with additional pipe bedding material. In wet conditions, 1'/4-inch minus crushed rock should be used to backfill the over -excavated portion of the trench. Over -excavation to remove unsuitable soils from below the pipeline should extend for the full depth on both sides of the pipe a distance which is equal to the depth of the over -excavation, or one pipe diameter, whichever is less. Where over -excavation and replacement with crushed rock is required, we recommend utilizing a low cost, non -woven, geotextile on the excavation base to act as a soil separator. This will prevent intrusion of fines into the crushed gravel and will reduce pumping; thus, facilitating compaction to a higher level than can normally be attained without the separator in place. Once crushed rock has been placed, and compacted in layers back to design trench base elevation, pipe bedding can be placed as described below. • Where the native subgrade soils are competent and do not require over -excavation, bedding material should be placed directly on undisturbed native soils. Trench bottoms should be free of debris and standing water. If subgrade soils are disturbed, the disturbed material should be removed and replaced with additional compacted bedding material. Pipe bedding material, placement, compaction, and shaping should be in accordance with the project specifications and the pipe manufacturer's recommendations. Pipe bedding should provide a firm uniform cradle for support of the pipes. A minimum bedding thickness of 6 inches should be placed beneath the pipe invert and should extend to a minimum of 12 inches above the pipe. Pipe bedding material around the pipe should be placed in layers and tamped around the pipe and under the haunches to obtain complete contact and support for the pipe. Pipe bedding material and any required areas of over -excavation should be compacted to achieve 90% of the maximum dry density (MDD) as determined by test method ASTM D1557 (Modified Proctor). 4.3.5 Trench Backfill Materials and Compaction Stonegate 11 Final Geotech Report.doc 24 HWA GeoSciences Inc. ' November 7, 2008 HWA Project No. 2007-080-21 T1200 Trench backfill material should consist of granular sand and gravel soils less than 3 inches ' maximum particle size, with no more than 30 percent fines (passing the U.S. No. 200 standard sieve), and moisture content within 3 percent of optimum. Based on our laboratory tests, a majority of the native sand and gravel soils will be suitable for use as trench backfill in dry weather conditions. Native fine-grained soils, very silty granular soils, and granular soils excavated from below the water table will be difficult to properly compact and are, therefore, not recommended for use as trench backfill. Ultimately, the suitability of on -site soils for use as trench backfill will vary depending on the compaction requirements, which are a function of whether the trench backfill will comprise ' subgrade for non-structural, non -paved, areas or comprise roadway subgrades or areas to be paved. In non-structural, non -paved, areas where trench backfill settlement is not a concern, backfill above the pipe zone should be compacted to at least 90 percent of the maximum dry ' density (MDD), as determined per ASTM D1557 (Modified Proctor). Beneath roadway or other areas to be paved, or areas where settlement is a concern, backfill placed above the pipe zone and ' to within 2 feet of the ground surface should be compacted to at least 90 percent of the Modified Proctor MDD, and backfill placed within 2 feet of the ground surface should be compacted to at least 95 percent of the Modified Proctor MDD. Figure 7 presents a graphical depiction of the recommended trench backfill compaction requirements. In some instances, relatively wet or silty soils may be compactible to 90 percent of the Modified Proctor MDD and, therefore, may be used in non-structural, non -paved, areas or at depths of more than 2 feet below the ground surface. Approval of such soils should be provided, on a case by case basis, by the geotechnical engineer. Soils that do not meet the gradation and moisture ' content requirements provided in the previous paragraphs, and that cannot be compacted to 90 percent of their Modified Proctor MDD, are unsuitable and should be exported from the site. Imported backfill material should meet the gradation and moisture requirements provided in the previous paragraphs. All trench backfill and compaction should be performed in a systematic manner and should be ' monitored by a representative of the geotechnical engineer. During placement of the initial lifts, the trench backfill material should not be bulldozed into the trench or dropped directly on the pipe. Furthermore, heavy vibratory equipment should not be permitted to operate directly over ' the pipe until a minimum of 2 feet of backfill has been placed over the pipe. Trench backfill materials should be placed in maximum 12-inch thick loose lifts and compacted to the required density using vibratory mechanical equipment. In areas where compaction equipment size is limited to a walk -behind roller, or jumping jack compactor, lift thicknesses should be limited to 4 to 6 inches. ' Trench backfill placed and compacted as recommended should be anticipated to settle approximately I to 2 percent of its total thickness. If 1 to 2 percent of post -construction settlement is not acceptable, the trench area should either be graded higher (mounded) during ' Stonegate II Final Geotech Report.doc 25 HWA GeoSciences Inc. ' November 7, 2008 HWA Project No. 2007-080-21 T1200 final grading to account for the potential settlement, or the trench should be backfilled with ' imported material consisting of 1'/4-inch minus crushed rock, with less than 5 percent fines, compacted to at least 95 percent of its Modified Proctor MDD. 4.3.6 Pipeline and Buried Structure Design Considerations Vertical loading on buried pipes is a function of the weight of the soil prism above the pipe and the rigidity of the pipe element. For design purposes, we recommend that the weight of the soil prism be determined from: W'p = ys(H + 0.11 DJD. Where: WSP = Soil prism load, lbs/ft. ' YS = Unit weight of soil; lbs/cu.ft., or pcf. H = Depth of fill over top of pipe, feet. Do = Outside diameter of pipe, feet. The load on the pipe may be determined from: ' WP = VAF x WSP ' Where: — WP Load on the pipe, lbs/ft. VAF = Vertical arching factor. ' The VAF for rigid pipe, installed under typical embankment construction conditions is almost always approximately 1.4; whereas, most flexible pipes are designed for a VAF of 1.0. The unit ' weight of the backfill soils will vary with the type of soil backfill utilized and degree of compaction attained. However, for the soil types existing along the project alignment and likely to be used for trench backfill we recommend a compacted unit weight of.130 pcf be used for design purposes. For design of flexible pipes, we recommend that the subgrade soil stiffness or modulus of soil reaction, E', be taken as 500 psi for medium stiff to stiff lacustrine clay and silty alluvial and outwash deposits (more than 12% fines) and 1500 psi for coarse sandy and gravelly deposits. For dense to very dense glacial till deposits, we recommend a modulus of 2000 psi. Specific ' reference should be made to the logs and Table 1 in assessing the appropriate soil subgrade conditions and design modulus. Where uncertainty regarding soil conditions exists, we recommend use of the lower value, and/or consultation with the geotechnical engineer. For design of foundations for structures such as manholes and buried vaults, we recommend a net allowable bearing pressure of 2000 psf for structures founded on fill and medium dense Stonegate II Final Geotech Report.doc 26 HWA GeoSciences Inc. L 1 November 7, 2008 HWA Project No. 2007-080-21 T1200 recessional outwash soils. We recommend a net allowable bearing pressure of 6000 psf for structures founded on dense to very dense advance outwash and glacial till deposits. We recommend an at -rest lateral earth pressure equivalent to that generated by a fluid with a unit weight of 60 pounds per cubic foot (pco for portions of structures above the ground water table. For design of buried structures below the ground water table, we recommend an at -rest lateral earth pressure equal to that generated by a fluid with a unit weight of 95 pcf. Lateral bearing pressures for design of thrust blocks may be taken as 1000 psf for recessional outwash and 3000 psf for advance outwash and till deposits. 4.3.7 Jacking and Insertion Pits Soldier piles and lagging may be suitable for shoring depending on the conditions and equipment used by the contractor. Jacking pits will likely require internal bracing. The insertion pit must be large enough to allow the pipe to be inserted from the surface into the pipe alignment without over -stressing the pipe by excessive bending. Manufacturer guidelines on minimum bending radius need to be closely adhered to. Soldier piles generally consist of steel 'H'-sections embedded in vertical, predrilled, concrete -filled, holes. They are typically installed 6- to 12-feet on center around the perimeter of the proposed excavation. As the excavation proceeds from the top down, lagging is placed to retain the soil between soldier piles, and cross -braces are installed to provide lateral support. Commonly, large steel sheets are used for lagging, although wooden timbers or pre -cast concrete panels can also be used. Temporary shoring is generally designed by the contractor; however, we have provided recommended earth pressures for preliminary planning and design of shored excavations on Figure 6. Because of the potential presence of water above or near the bases of pit excavations, dewatering of some of the excavations will be required. Dewatering wells should be located at least 5 feet outside the perimeter of the shored excavation. Soldier piles should penetrate at least 6 feet below the bottom of the excavation, but should be deeper as necessary to provide adequate kick -out resistance. Recovery of the soldier piles should be possible if they are set in lean concrete. Lagging should be installed as the excavation proceeds, and not more than 4 feet of unsupported excavation (measured vertically) should be exposed at one time. Space behind the lagging should be filled with freely draining material. 4.4 SEISMIC CONSIDERATIONS The project site lies within Seismic Zone 3, as defined in the Uniform Building Code (UBC, 1997). Zone 3 includes all of western Washington, and represents an area of moderate seismic risk. Consequently, moderate levels of earthquake shaking should be anticipated during the design life of the proposed improvements, and the facilities should be designed to resist earthquake loading in accordance with applicable local and state requirements. Stonegate II Final Geotech Report.doc 27 HWA GeoSciences Inc. November 7, 2008 HWA Project No. 2007-080-21 T1200 Based on the subsurface conditions observed during our exploration program along the proposed sewer pipeline alignment, 2003 IBC Site Class D may be assumed for the project. The generalized procedure outlined in the IBC. should be utilized in determining the appropriate response spectra for the project alignment. Soil liquefaction is a phenomenon wherein saturated soil deposits temporarily lose strength and behave as a liquid in response to moderate to severe earthquake shaking. Soil liquefaction is generally limited to loose granular soils located below the water table. We expect that liquefaction potential is highest within the area planned to accommodate the new Stonegate II lift station which is underlain by layers of loose to medium dense saturated granular sands and gravels that may liquefy during a moderately large seismic event. However, we anticipate potential liquefaction of lenses of soil above the new force main will be mitigated due to the backfill over the trench being compacted and less prone to liquefaction than the existing soil. Seismic induced landslide and ground surface rupture hazards were assessed for the force main alignment and are considered to be negligible to low. ' 4.5 WET WEATHER EARTHWORK 0 Although silty glacial soils are moisture sensitive and wet weather earthwork is not recommended when such soils are involved, such as within this project, general recommendations relative to earthwork performed in wet weather or in wet conditions are presented below. These recommendations should be incorporated into the contract specifications. • Earthwork should be performed in small areas to minimize exposure to wet weather. Excavation or the removal of unsuitable soil should be followed promptly by the placement and compaction of clean trench backfill. The size and type of construction equipment used may need to be limited to prevent soil disturbance. • Material used as trench backfill fill should consist of clean granular soil with less than 5 percent fines, which is a restriction on the trench backfill specification presented in Section 4.2.8. The fines should be non -plastic. Native soils that do not meet these requirements may be stockpiled for use in dry conditions or replaced with imported material. • Surface water should be prevented from draining into the trench. • Excavation and placement of structural fill material during wet weather should be observed by a representative of the geotechnical engineer, to determine that the work is being accomplished in accordance with the project specifications and the recommendations contained herein. Stonegate II Final Geotech Report.doc 28 HWA GeoSciences Inc. ' November 7, 2008 HWA Project No. 2007-080-21 T1200 4.6 DRAINAGE AND EROSION CONSIDERATIONS ' The native site soils are easily erodible when exposed and subjected to surface water flow. Surface water runoff can be controlled during construction by careful grading practices. Typically, these include the construction of shallow earthen berms and the use of temporary ' sumps to collect runoff and prevent water from damaging exposed subgrades. All collected water should be directed under control to a suitable discharge system. Erosion can also be limited through the judicious use of silt fences and straw bales. The contractor should be responsible for control of ground and surface water and should employ sloping, slope protection, ditching, sumps, dewatering, and other measures as necessary to prevent erosion of soils, consistent with best management practices required by the City of Renton and other applicable regulatory agencies. In this regard, grading, ditching, sumps, dewatering, and other measures should be employed as necessary to permit proper completion of the work. 5.0 CONDITIONS AND LIMITATIONS We have prepared this preliminary report in support of Roth Hill Engineering Partners, Inc. design for the proposed Stonegate II Sewer System Improvement project in Renton, Washington. Experience has shown that subsurface soil and ground water conditions can vary significantly over small distances and over time; hence, we may not have seen every condition and even those we saw can change with time. The scope of our work did not include environmental assessments or evaluations regarding the presence or absence of wetlands or hazardous substances in the soil, surface water, or ground water at this site. HWA does not practice or consult in the field of safety engineering. O.O Stonegate II Final Geotech Report.doc 29 HWA GeoSciences Inc. 1- 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 November 7, 2008 HWA Project No. 2007-080-21 T1200 We appreciate the opportunity to be of service. If you have any questions or concerns, please do not hesitate to contact us. Sincerely, HWA GEOSC[ENCES INC. -'C+� 17D4 �• 1/7�°� STEVEN ELLIOTT GREENE Steven E. Greene, L.E.G. Vice President SEG:eoa:seg Stonegate ii Final Geotech Report O, ANZ) was�'4s� +� 36468 �� 4 f L'GIS'r6R� AL Fl�G` !vw •' W�� EXPIRES 08 / 18 rlpr 10 Erik O. Andersen, P.E. Geotechnical Group Manager 30 HWA GeoSciences Inc. November 7, 2008 HWA Project No. 2007-080-21 T1200 6.0 REFERENCES Booth, D.B, and A.A. Wisher, 2006, Composite Geologic Map of King County, Washington, University of Washington, Department of Earth and Space Sciences-GeoMapNW. Trenchless Technology Center (TTC), 2001, Guidelines for Pipe Bursting, Prepared by TTC for the U.S. Army Corps of Engineers -Engineering Research and Development Center (ERDC), Vicksburg, MS, 47 p. WSDOT, 2008, 2008 Standard Specifications for Road, Bridge, and Municipal Construction, Washington State Department of Transportation and American Public Works Association. Stonegate II Final Geotech Report.doc 31 HWA GeoSciences Inc. TOP01 map printed on 07/11/07 from "Washington. too" and "Untitled.tDa" 1� �auo re, o wo ,000 Marra Pmted Gam TOP01 02001 Netmrl G.V Vhr Holdings i ^A ropo wm) PROJECT SITE & VICINTY MAP FINAL GEOTECHNICAL REPORT VLllia� H` AGEOSCIENCES INC. SEWER REPLACEMENT -ROUTE INVESTIGATION STONEGATE-SUMMERWIND-PHASE II IMPROVEMENTS z c z FIGURE NO. 2007-080 r �5Th C-Ti ® BH-1 HWA Exploratory Boring Gravity Sewer Alignment _ Y�� HWA GEOSCI ENCES INC. Exploration Task Area and Designation Stonegate II Force Main Alignment 'ROJECT ALIGNMENT & EXPLORATION LOCATIONS PHASE II GEOTECHNICAL INVESTIGATION RENTON — STONEGATE II -SEWER IMPROVEMENTS RENTON, WASHINGTON IGURE NO. PROJECT NO 2007-080 d LEGEND BH-1 BOREHOLE DESIGNATION AND APPROXIMATE LOCATION BASE f44P PROVIDED BY S:\2007 PROJECTS\2007-080-21 STONEGATE II -SEWER SYSTFM 2007 OVERVIEW o G' 25S0' 100 SCALE: 1' - 50' Phase II Geotechnical Engineering Services FORCE MAIN ALIGNMENT DRAWN BY EFK FIGURE F70.— FMGEOSCIENMINC. Renton - Stonegate II -Sewer Improvements SITE AND CHECK BY DC EXPLORATION PROM CT U0. Renton. Washington PLAN DACE 2007-080-21 05.13.08 TACIT VVV �_✓' ,/\� OVERVIEW i v 13H-3B j BH-3A z v ti iF LEGEND BH-1 30- BOREHOLE DESIGNATION AND APPROXIMATE LOCATION HWAGEOSCIENCESINC BASE M- P PROVIDED BY S:\2007 PROJECTS\2007-080-21 STONEGATE II -SEWER SYSTEM o s 50 100 SCALE: 1'-50' FIGURE PROJECT NO. 2007-080-21 L ' LEGEND BH-1 * BOREHOLE DESIGNATION AND APPROXIMATE LOCATION 1 BASE MAP PROVIDED UY S:\2007 PROJECTS\2007-080-21 STONEGATE II -SEWER -=------ - - -- - Y y OVERVIEW t, ti 1 0 15, S0 I0`) SCAtC V-SO' Phase II Geotechnical Engineering Services FORCE MAIN ALIGNMENT DRAWN BY EFK FIGURE NO. MTHWAGEOSCIENCES INC. Renton - Stonegate 11-Sewer Improvements SITE AND CHECK BY DC - 3C , IEXPLORATION PROJECT No. Renton, Washington PLAN DATE 2007-080-21 05.13.08 TACIT VVV U rV " •.,. w L7 j w BH-5 z i U IV ."E. f.5r.!•.r ------_777-- ---- --Tip=== __ _ 777 1 --- L BH_ i LEGEND BH-1 * BOREHOLE DESIGNATION AND APPROXIMATE LOCATION BASE MAP PROVIDED BY S:\2007 PROJECTS\2007-080-21 STONEGATE II —SEWER SYSTEM IMPROVEMENTS\CAD 2007-080\HWA 2007—OBO.DWG Phase II Geotechnical Engineering Services fMGEOJCIENCH INC Renton- Stonegate II -Sewer Improvements 1 Renton, Washington OVERVIEW M D n r H z M G) c 70 M N M s 0' 25' 50' 160 SCALE: C=50' FIGURE NO. 3D PRO)ECT NO. 2007-080-21 TASK XXX MATCHLINE FIGURE 2E / U! ZZ/ - - --- H M H^ G C 70 rn fV G) NOTE: This alignment is no longer under consideration BH-1 30- BOREHOLE DESIGNATION AND APPROXIMATE LOCATION BASE I^.AP PROvIEFI) BY S:\2007 PRO.IECTS\2007-080-21 STONEGATE II -SEWER SYSTEM IMPROVEMENTS\CAD 2007- OVERVIEW � ►b- 0' 25' 50 100' SCALE: 1'-SV D RA1'/H BY EFK FIGURE NO. Phase II Geotechnical Engineering Services FORCE MAIN ALIGNMENT IMGEOSCIENCES ING Renton - Stonegate II -Sewer Improvements SITE AND CHECK BY DC 1 EXPLORATION PRO)ECT NO. Renton, Washington PLAN DATE2007-080-21 05.13.08 TACV VVV OVERVIEW 1'l N W L1J ,- - - --- IIT J U _. /1L //., -ILL---_--- .. - - - - - -1LL_ _ 1 NOTE: This alignment is no longer under consideration LEGEND BH-1 BOREHOLE DESIGNATION AND APPROXIMATE LOCATION BASE NAP PROVICED BY S \2007 PROJECTS` 0• 2Sw 100' SUL E : 1'- 50' Phase II Geotechnical Engineering Services FORCE MAIN ALIGNMENT DRAwH ev EFK HWAGEOSCIENCESING Renton - Stonegate II -Sewer Improvements SITE AND CHECK BY DC ' EXPLORATION PROJECT NO. Renton, Washington PLAN DATE2007-080-21 _- 05.13.08 TACV VVV 2007- LEGEND BH-1 BOREHOLE DESIGNATION AND APPROXIMATE LOCATION BASE 14AP PROVIDED BY S:\2007 PROJECTS\2007-080-21 STONEGATE II -SEWER SYSTEM IMPROVEMENTS\CAD 2007-080\HWA OVERVIEW i V 25' SO' 1 U J SCALE: V50' Phase II Geotechnical Engineering Services SUMMER WIND, DRAWN BY EFK FIGURE NO. STONEGATE CONNECTOR IMGEOSCIENCES INC. Renton - Stonegate II -Sewer Improvements SITE AND CHECK BY DC um-- PROJECT NO. Renton, Washington EXPLORATION DATE 2007-080-21 ___ PLAN 05.13.08 TACIT VVV LEGEND BH-1 _0�- BOREHOLE DESIGNATION AND APPROXIMATE LOCATION BASE MAP PROVIDED BY S: \2007 PROJECTS' II -SEWER SYSTEM IA!P Im = aow— 0' 25 50100 iiiiiii SCALE: FSO' OVERVIEW i� J i MATCHLINE FIGURE 4C "M'Wl� m MAW Lu W a Z U Q Phase II Geotechnical Engineering Services STONEGATE LIFT STATION DRAi'!N BY EFK t IG'JRt NO, — HWAGEOSCIENCESINC Renton - Stonegate II -Sewer Improvements SITE AND CHECK BY DC 5A ' Renton, VVashin ton EXPLORATION DATE PROJECT NO g PLAN 2007-080-21 05.13.08 TACV VVV I I sT�zaa � xiar w BH-11 � � t �0. HI , LEGEND BH-1 BOREHOLE DESIGNATION AND APPROXIMATE LOCATION BASE I IAP PROVIDED BY t1. OVERVIEW a-,, 10.-- 0' 25' 50 100 SCALE: 1'=50' Phase II Geotechnical Engineering Services STONEGATE LIFT STATION 11RAW11BYEEK '-- -'-- gon WAGEOSCIENCESINC. Renton - Stonegate II -Sewer Improvements SITE AND CHECK BY 5B Renton, Washington EXPLORATION DATE PROJECT NIC. g PLAN 2007-080-21 05.13.08 TAr-V Vw 21 STONEGATE II -SEWER SYSTEM IMPROVEMEN LEGEND BH-a BOREHOLE DESIGNATION AND APPROXIMATE LOCATION BASE MAP PROVIDED BY S:\2007 PROJECTS\2007-080-21 STONEGATE II -SEWER SYSTEM IMPROVEMENTS\CAD 2007-080\HWA 2007- BH-13 BH-14 HMGEOSCIENCES INC m OVERVIEW 1 V�P 0 25 59 100, SCALE: 1'=50 O)ECT NO. 2007-080-21 TASK )= 1 5' 22H ' - INTERNALLY BRACED SHEET PILE WALL ' 11H H H ' BOTTOM OF EXCAVATION DESIGN WATER LEVEL INSIDE t_ EXCAVATION ' 85psf D III 188D 62,4(H-5) ' SURCHARGE HYDROSTATIC ACTIVE NET PASSIVE PRESSURE PRESSURE PRESSURE PRESSURE 1 ' NOTES: 1. GROUND WATER OUTSIDE SHORING ASSUMED TO BE 5FT BELOW GROUND SURFACE. ' 2. DESIGN PRESSURES ARE IN UNITS OF psf; DISTANCES ARE IN UNITS OF FEET. 3. SURCHARGE LOADS SHOULD BE ADDED WHERE APPROPRATE. 4. SHORING EMBEDMENT (D) SHOULD BE DETERMINED BY SOLVING EQUILBRIUM EQUATIONS; /o ' THE COMPUTED EMBEDMENT DEPTH SHOULD BE INCREASED BY 20 , AND D SHOULD BE NOT LESS THAN 15 FEET. 1 ' DESIGN EARTH PRESSURES FOR D1AWN BY � �tDuRE NO.. TEMPORARY BRACED SHORING a+ECKED er EA 1WQ0 f,7V1GNVrSINC DATE PROJECT NO. Phase II Geotechnical Engineering Services Renton - Stonegate II -Sewer Improvements 11.06.08 2007-080 Renton, Washington ' SA2007 PROJECTSl2007-080-21 STONEGATE II -SEWER SYSTEM IMPROVEMENTSICAD 2007-9801EARTH PRESSURES.DWG <8.5x11 Figwe6> Plclted111620C8 4:20 PM REV 00 EFx OVOW06 PROPOSED BUOYANCY RESISTING STRUCTURE SOIL OVER EXPANDED BASE ' DESIGN GROUNDWATER LEVEL 4 1 , d ' WB T Fsw 1 �� H Fss T 1111 W 1 Q. 4!,4. e ' Fs* B * Buoyant force could result in high ' bending moments in slab ' SYMBOL ASSUMPTIONS ' B = Width of extended base in feet Buoyant Soil Unit Weight = 68 pcf W = Structure weight in kips Soil Friction Angle = 30' At —rest Pressure Coefficient = 0.50 WB = Buoyant soil weight above base in kips ' FB = Buoyant force in kips = Unit weight of water x volume of NOTES structure below design ground —water level Factor of Safety = W+FSw L L = Perimeter around base of wall in feet Fe (without extended base, FSS = Shearing resistance of soil as indicated on the left side) ' = 0.0084H2 (in kips per foot of wall) Factor of Safety = W + WB + FSS L FSw = Shearing resistance of soil —wall FB ' contact 0.00531-12 (with extended base around perimeter of structure, (in kips per foot of wall) as indicated on the right side of this figure) PARAMETERS FOR CALCULATING ,PAW,, FtBURf NO. ' UPLIFT RESISTANCE cHECKEO er EA 7 HWAGWSMNCB INC 1 Phase II Geotechnical Engineering Services DATE PROJECT NO. Renton - Stonegate II -Sewer Improvements 11.06.08 2007-080 Renton, Washington S12007 PROJECTSl2007-080-21 STONEGATE II -SEWER SYSTEM IMPROVEMENTS%CAD 2007-0801EARTH PRESSURES.DWG <8.5x11 Figure7> Plotted: 11I672008 3:41 PM REV w EFK 01/09/06 APPENDIX A FIELD EXPLORATIONS 1 IStonegate 11 Final Geotech Report.doc HWA GeoSciences, INC. n 1 RELATIVE DENSITY OR CONSISTENCY VERSUS SPT N-VALUE COHESIONLESS SOILS COHESIVE SOILS Approximate Approximate Density N (blows!(() Relative Density(%) Consistency N (blowstft) Undrolned Shear Strength (psf) Very Loose 0 to 4 0 - 15 Very Soft 0 to 2 <250 Loose 4 to 10 15 - 35 Soft 2 to 4 250 - 5W Medium Dense 10 to 30 35 65 Medium Stiff 4 to 8 500 - 1000 Dense 30 to 50 65 - 85 Ste 8 to 15 1000 - 2000 Very Dense over 50 85 - 100 Very Stiff 15 to 30 2000 - 4000 Hard over 30 >4000 USCS SOIL CLASSIFICATION SYSTEM MAJOR DIVISIONS GROUP DESCRIPTIONS Coarse Graval and Clean Gravel Im a I& GW Well -graded GRAVEL Grained Gravelly Soils (little or no lures) Soils o GP Poorly -graded GRAVEL More than 50% of Coarse Gravel vrith a GM Silty GRAVEL Fraction Retailed Fines (appreciable On' No. 4 Sieve amount of fines) GC Clayey GRAVEL Sand and Clean Sand ;• SW Well -graded SAND More than Sandy Sols (little or no fires) SP Poorly -graded SAND 50% Retained 50% or More on No. of Coarse Sand with SM Silty SAND 200 Sieve Fraction Passing Fines (appreciable Size No. 4 Sieve amount of fines) .' SO ClayeySAND I I I ML SILT Fine Silt Grained and Liquid Lunt CL Leon CLAY Soils Less than 50% Clay _ — OL Organic SILT/Organic CLAY MH Elastic SILT 50% or More Sill Liquid Limit Passing and 50%or More CH Fal CLAY No. 200 Sieve Clay Size OH Organic SILTIOrganic CLAY Highly Organic Soils — r u PT PEAT COMPONENT DEFINITIONS COMPONENT SIZE RANGE Boulders Larger than 12 i1 Cobbles 3 in to 12 in Gravel 3 in to No 4 (4.5mm) Coarse gravel 3 in to 3/4 in Fine gravel 314 in to No 4 (4.5mm) Sand No. 4 (4.5 mm) to No. 200 (0.074 mm) Coarse sand No. 4 (4.5 mm) to No. 10 (2.0 mm) Medium sand No. 10 (2.0 mm) to No. 40 (0.42 rrm) Fine sand No. 40 (0.42 mm) to No. 200 (0.074 mm) Sill and Clay Smaller than No. 200 (0.074mm) TEST SYMBOLS %F Percent Fines AL Atterberg Limits: PL = Plastic Limit LL = Liquid Limit CBR Calitomia Bearing Ratio ON Consolidation DD Dry Density (pc) DS Direct Shear GS Grain Size Distribution K Permeability MD Moisturel0ensity Relationship (Proctor) MR Resilient Modulus PID Phololonizatlon Device Reading PP Pocket Penetrometer Approx. Compressive Strength (tsq SG Specific Gravity TO Triaxlal Compression TV Torvane Approx. Shear Strength (tsp UC Unconfined Compression SAMPLE TYPE SYMBOLS ® 2.0" 00 Split Spoon (SPT) (140 lb. hammer with 30 in. drop) IShelby Tube 3-114" OD Split Spoon with Brass Rings OSmall Bag Sample 0 Large Bag (Bulk) Sample nCore Run Non-standard Penetration Test (3.0' OD split spoon) GROUNDWATER SYMBOLS j� Groundwater Level (measured at time of drilling) Groundwater Level (measured in well or Open hole after water level stabilized) COMPONENT PROPORTIONS PROPORTION RANGE DESCRIPTIVE TERMS < 5% Clean 5 - 12% Slightly (Clayey, Silty, Sandy) 12 - 301A Clayey, Silly, Sandy, Gravelly 30-50% Very (Clayey, Silty, Sandy, Gravelly) Components are arranged in order of Increasing quantities. NOTES: Soil classifications presented on exploration logs are based on visual and laboratory observation. Soil descriptions are presented in the following general order: MOISTURE CONTENT Density/consistency, color, mod7ffer (d any) GROUP NAME, additions to group name (Ifany), moisture DRY Absence of moisture, dusty, content. Proportion, gradation, and angularity, of constituents, additional comments. dry to the touch. (GEOLOGIC INTERPRETATION) MOIST Damp but no visible water. Please refer to the discussion in the report text as well as the exploration togs for a more WET Visible tree water, usually complete description of subsurface conditions. soil is below water table. GEOTECHNICAL DATA REPORT LEGEND OF TERMS AND '1 SEWER REPLACEMENT ROUTE INVESTIGATION SYMBOLS USED ON HMGEOSCIENCESINC. RENTON-STONEGATE-II EXPLORATION LOGS RENTON, WASHINGTON _ PROJECT NO.: 2007-080-21 FIGURE: A'1 LEGEND 2007-080.GPJ 10/29108 DRILLING COMPANY: Gregory Drilling Inc. LOCATION: See Figure 2 DRILLING METHOD: Truck Mounted Hollow Stem Auger DATE STARTED: 05/08/2008 SAMPLING METHOD: SPT w/Auto hammer DATE COMPLETED: 05108/2008 SURFACE ELEVATION: 416 * feet LOGGED BY: T. Taddese 5- 10- m w z w Standard Penetration Test UJ a. Ln .5 N (140 lb. weight, 30" drop) IF- ♦Blows per foot w w Q. 0- W w z 0 � DESCRIPTION a g O p Asphalt Q GP Medium dense, gray, fine to coarse GRAVEL with fine to ° coarse sand and trace silt. o _______ (TRENCH FILL) Medium dense, rust mottled, gray to yellowish gray, fine SM gravely, fine to medium SAND, moist. ........................................................... Medium dense, light yellowish gray, One to coarse gravelly, SM fine to medium SAND, moist. .................................. Dense, olive gray, silty, fine to medium SAND with fine gravel, SM moist. Borehole terminated at a depth of about 6 feet below existing ground surface. No ground water seepage was observed during drilling. S-1 25-15.10 S-2 4-7.4 S-3 4114-20 I— 5 '— 10 For a proper understanding of the nature of subsurface conditions, this 0 20 40 60 80 100 exploration log should be read in conjunction with the text of the water Content I%) geotechnical report. Plastic Limit I--0 Liquid Limit Natural Water Content NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated and therefore may not necessarily be indicative of other limes and/or locations. ♦ GEOTECHNICAL DATA REPORT BORING: SEWER REPLACEMENT ROUTE INVESTIGATION BH- 1A imaosaENCES INC. RENTON-STONEGATE-II PAGE: 1 of RENTON, WASHINGTON PROJECT NO.: 2007-080-21 Ft RE' A-2 BORING 2007-080.GPJ 10129108 DRILLING COMPANY: Gregory Drilling Inc. LOCATION: See Figure 2 DRILLING METHOD: Truck Mounted Hollow Stem Auger DATE STARTED: 05/08/2008 SAMPLING METHOD: SPT w/Auto hammer DATE COMPLETED: 05/08/2008 SURFACE ELEVATION: 416 t feet LOGGED BY: T. Taddese rn IJJ U a m ? z -- < t Cn w Q U J y W W W p ~ Z 0- y 2 U 2 z o x O LIJo W M DESCRIPTION (D ua) a O 0 0 0 5- I 10- ibZ Asphalt GP Medium dense, gray, fine to coarse GRAVEL with fine to S-1 24.45.35 SM coarse sand and trace silt. j --------- (FILL)---------� ML Dense, brown, fine gravelly, silty, fine to medium SAND. SM moist. Very dense, olive gray, fine gravelly, silty, fine to medium S-2 14-28-20 SAND to hard, fine gravelly, fine to medium sandy SILT, moist. (VASHON GLACIAL TILL) SM — — — — — — Dense to very dense, olive gray, fine to coarse gravelly, silty, fine to medium SAND, moist. W S-3 26-50/5" SA 15-30.50/5' Trace organics noted at about 10 feet below existing ground S-5 9-16.23 surface. S-8 22-46-39 Borehole terminated at a depth of about 14.0 feet below existing ground surface. No ground water seepage was observed during drilling. 20 J For a proper understanding of the nature of subsurface conditions, this exploration log should be read in conjunction with the text of the geotechnical report. NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated and therefore may not necessarily be indicative of other times and/or locations. Standard Penetration Test (140 lb. weight, 30" drop) ♦ Blows per foot IL W41 10 20 30 40 50 o 41 w 5 Rr1• 15 1 20 0 20 40 60 80 100 Water Content (%) Plastic Limit 1--0 Liquid Limit Natural Water Content >> GEOTECHNICAL DATA REPORT BORING: SEWER REPLACEMENT ROUTE INVESTIGATION BH- 1 B HWAGEOSCIENCH INC. RENTON-STONEGATE-II PAGE: 1 of 1 RENTON, WASHINGTON PROJECT NO.: 2007-080-21 FIG I URE: A-3 BORING 2007-0aO.GPJ 10129/08 DRILLING COMPANY: Gregory Drilling Inc. LOCATION: See Figure 2 DRILLING METHOD: Truck Mounted Hollow Stem Auger DATE STARTED: 05/0812008 SAMPLING METHOD: SPT w/Auto hammer DATE COMPLETED: 05/0812008 SURFACE ELEVATION: 414 3 feet LOGGED BY: T. Taddese rn m w z w Standard Penetration Test U a ? ) a (140 lb. weight, 30" drop) p z vJ F p ♦ Blows per fool F^ Lu a s w � v wn m U) Lo U DESCRIPTION vdi vdi a g O d f 0 10 20 30 40 50 0 0 Asphalt GP Medium dense, gray, fine to coarse GRAVEL with fine to ° S-1a 12-9-7 coarse sand and trace silt. o (TRENCH FILL) SM Medium dense, gray and light yellow brown, silly, One to .......... coarse gravelty, fine to medium SAND, moist. S-1b S-2 4.6.5 ML Loose to medium stiff, light yellow brown and gray, silty, fine — S-3 4.4-3 SM gravelly, fine SAND to fine sandy, fine gravely, SILT, moist. Trace organics. ...................:.... 5 :....:.............. 5 Borehole terminated at a depth of about 5.0 feet below existing ground surface. No ground water seepage was observed during drilling. ' 10 10 0 20 40 so 80 100 For a proper understanding of the nature of subsurface conditions, this exploration log should be read in conjunction with the text of the water Content (%) geotechnical report. Plastic Limn 1 0 Liquid Limit Natural Water Content NOTE. This log of subsurface conditions applies only at the specified location and on the date indicated and therefore may not necessarily be indicative of other times and/or locations. GEOTECHNICAL DATA REPORT BORING: SEWER REPLACEMENT ROUTE INVESTIGATION BH- 2A HmaosamES INC. RENTON-STONEGATE-II PAGE: 1 of RENTON, WASHINGTON PROJECT NO.: 2007-080-21 FIGURE: A-4 BORING 2007-080.GPJ 10129/08 DRILLING COMPANY: Gregory Drilling Inc. SURFACE ELEVATION: 414.00 t feet DATE STARTED: 05/08/2008 DRILLING METHOD: Truck Mounted Hollow Stem Auger DATE COMPLETED: 05/08/2008 SAMPLING METHOD: SPT wlAuto hammer LOGGED BY: T. Taddese LOCATION: See Figure 2 5- 10- 15- 20 - DESCRIPTION Asphalt GP Medium dense, gray, fine to coarse GRAVEL with fine to sand and trace silt. ! SM 'coarse (FILL) — Medium dense, brown, silty SAND with scattered gravel, moist. Trace organics noted. SM Very dense, slightly rust mottled, gray, fine to coarse gravely, silly, fine to medium SAND, moist. (VASHON GLACIAL TILL) Borehole terminated at a depth of about 12.9 feet below existing ground surface. No ground water seepage was observed during drilling. � w w LU 7 ~ t W } F z NujwF y U n . a a w pw d a u� o vim) 0 5-1 11-10.8 S-2 10-5015" S-3 32/50/5" N 5-4 5015" AS-5 16.50/4" 5Q S-6 5015" 0 NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated I. and therefore may not necessarily be indicative of other times and/or locations. Standard Penetration Test (140 lb. weight, 30" drop) ♦ Blows per foot S Uj o. m 10 20 30 40 50 a . r0 5 10 1 15 1 `20 20 40 60 80 100 Water Content I%) Plastic Limit 1 0 Liquid Limit Natural Water Content GEOTECHNICAL DATA REPORT BORING: 1 SEWER REPLACEMENT ROUTE INVESTIGATION BH- 2B HMIGEOSCIENCES INC RENTON-STONEGATE-I I PAGE: t of 1 RENTON, WASHINGTON PROJECT NO., 2007-080-21 FIGURE: A-5 PZO 2007-080.GPJ 10129108 DRILLING COMPANY: Gregory Drilling Inc. LOCATION: See Figure 2 DRILLING METHOD: Truck Mounted Hollow Stem Auger DATE STARTED: 06108/2008 SAMPLING METHOD: SPT w/Auto hammer DATE COMPLETED: 05/08/2008 SURFACE ELEVATION: 431 t feet LOGGED BY: T. Taddese 5 DESCRIPTION w m a z d F W Q w � a z w w 0 0 a- O Asphalt ° Q GP Medium dense, gray, fine to coarse GRAVEL with fine to coarse sand and trace sift. o FILL)________ SM _^_____,TRENCH Medium dense, light yellow brown and olive gray, silty, fine to coarse gravelly, fine to medium SAND, moist. ............................................... Loose, light brown, silty, fine gravely, fine to medium SAND, SM moist. Loose, light yellow brown and strong brown, silty, fine to SM medium SAND wilh fine to coarse gravel, moist. Borehole terminated at a depth of about 5.5 feet below eAsting ground surface. No ground water seepage was observed during drilling. S-1 15-13-9 S-2 4-4-3 S-3 3-3-4 10 — For a proper understanding of the nature of subsurface conditions, this exploration log should be read in conjunction with the text of the geotechnical report. NOTE: This log of subsurface conditions applies only at the specified location and on (he dale indicated and therefore may not necessarily be indicative of other times and/or locations. Standard Penetration Test (140 lb. weight, 30" drop) ♦ Blows per foot x ~a4) 10 20 30 40 50 o �' 0 ♦ Ir -5 IL10 0 20 40 60 80 100 Water Content (%) Plastic Limit 1--0 Liquid Limit Natural Water Content GEOTECHNICAL DATA REPORT BORING: 1 SEWER REPLACEMENT ROUTE INVESTIGATION BH- 3A HMGEOSCIENMINC. RENTON-STONEGATE-11 PAGE: 1 of i RENTON, WASHINGTON PROJECT NO.: 2007-080-21 FIGURE A-6 BORING 2007-080.GPJ 10r2 M Asphalt GMDense, gray, fine to coarse GRAVEL with fine to coarse sand I and trace silt. (FILL) Medium dense, olive gray and olive brown, fine to coarse gravely, fine to medium SAND, moist. Organics noted. ML Loose to medium stiff, olive gray to olive brown, fine gravely, SM silty, fine to medium SAND to fine gravelly, fine to medium sandy, SILT, moist, (WEATHERED TILL) SM Very dense, olive gray, fine to coarse gravelly, silty, fine to medium SAND, moist. (VASHON GLACIAL TILL) GEOTECHNICAL DATA REPORT BORING: ' ' SEWER REPLACEMENT ROUTE INVESTIGATION BH- 3B ,MGEOSCIENCES INC RENTON-STONEGATE-II PAGE: I of 1 RENTON, WASHINGTON PROJECT NO.: 2007-080-21 FIGURE, A-7 BORING 2007MO,GPJ 10129/08 DRILLING COMPANY: Gregory Drilling Inc. LOCATION: See Figure 2 DRILLING METHOD: Truck Mounted Hollow Stem Auger DATE STARTED: 05/08/200B SAMPLING METHOD: SPTw/Auto hammer DATE COMPLETED: 05/08/2008 SURFACE ELEVATION: 487 t feet LOGGED BY: T. Taddese 5- m w z 0 of w Standard Penetration Test 0- t 0)¢ (140 lb. weight, 30" drop) LU rn Fw o ♦ Blows per foot LU a� w a W co w 0 x DESCRIPTION W a 8 O (D — _ __ _ __ 0 w Asphalt GP Medium dense, gray, fine to coarse GRAVEL with fine to ° coarse sand and trace silt. o ------- TRENCH FILL) —_______ Medium dense, light yellow brown, silty, fine gravelly, fine to SM medium SAND, moist. ...................................................... Medium dense, light yellow brown to reddish brown, fine SM gravelly, fine to medium SAND, moist. Organics noted. ............................... Dense, olive gray, fine to coarse gravelly, silty, fine to medium SM SAND, moist. Borehole terminated at a depth of about 5.5 feet below existing ground surface. No ground water seepage was observed during drilling. S-1 6-11-13 S-2 5.5-14 S-3 6-19-15 10 — For a proper understanding of the nature of subsurface conditions, this exploration log should be read in conjunction with the text of the geotechnical report. NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated and therefore may not necessarily be indicative of other times and/or locations. I-5 L 10 0 20 40 60 80 100 Water Content (%) Plastic Limit 1--0--J Liquid Limit Natural Water Content A GEOTECHNICAL DATA REPORT BORING: SEWER REPLACEMENT ROUTE INVESTIGATION BH- 4A HMGEOSCIENCH INC. RENTON-STONEGATE-II PAGE: 1 of 1 RENTON, WASHINGTON PROJECT NO.: 2007-080-21 FIGURE• A-H BORING 2007-080.GPJ 10/29/08 DRILLING COMPANY: Gregory Drilling Inc. LOCATION: See Figure 2 DRILLING METHOD: Truck Mounted Hollow Stem Auger DATE STARTED: 05/08/2008 SAMPLING METHOD: SPT w/Auto hammer DATE COMPLETED: 05/08/2008 SURFACE ELEVATION: 487 t feet LOGGED BY: T. Taddese 5- 1 10- ib`1C DESCRIPTION Asphalt GP Medium dense, gray, fine to coarse GRAVEL with fine to coarse sand and trace silt. J SM 1 FILL : Medium dense, light brown to olive brown, silty, fine gravelly, -'. SM .fine to medium SAND, moist. Organics noted. ......................................................... Very dense, light yellow brown, fine to coarse gravelly, silty, fine to medium SAND, moist. Trace organics noted. SM Dense to very dense, gray to olive gray, silty, fine to medium SAND with fine to coarse gravel, moist. (VASHON GLACIAL TILL) Borehole terminated at a depth of about 13.25 feet below existing ground surface. No ground water seepage was observed during drilling, m w z — w Standard Penetration Test w F Q (140 lb. weight, 30" drop) Z rn so Lu F a ♦ Blows per foot as a i w x cn w a 3 ~ O X O w � 09 0 10 20 30 40 50 S-1 10-8-9 S-2 5-15-36 S-3 12-16-20 SA 14-43-50/5" X S-5 45-50/5" XS-6 44.50/3" 20 J For a proper understanding of the nature of subsurface conditions, this exploration log should be read in conjunction with the text of the geotechnical report. NOTE: This log of subsurface conditions applies only at the specified location and on the dale indicated and therefore may not necessarily be indicative of other times and/or locations. 0 20 40 60 80 100 Water Content (%) Plastic Limit 1-- 0 Liquid Limit Natural Water Content 0 1 5 1 GEOTECHNICAL DATA REPORT BORING: SEWER REPLACEMENT ROUTE INVESTIGATION BH- 4B FIMGEOSCIENCES INC. RENTON-STONEGATE-11 PAGE: 1 of 1 BORING 2007-060.GPJ 10129108 RENTON, WASHINGTON PROJECT NO.: 2007-080-21 FIGURE A-9 or DRILLING COMPANY: Gregory Drilling Inc. LOCATION: See Figure 2 DRILLING METHOD: Truck Mounted Hollow Stem Auger DATE STARTED: 05/07/2008 SAMPLING METHOD: SPT w/Auto hammer DATE COMPLETED: 05/0712008 SURFACE ELEVATION: 440 3 feet LOGGED BY: T. Taddese mic Ii11 C IiF419 1 20- 1 25 - DESCRIPTION Asphaft GP Medium dense, gray, fine to coarse GRAVEL with fine to MIL } coarse sand and trace sift. j `_________ (FILL) __ I SM Hard, dark brown, fine sandy, SILT with scattered fine gravel, moist. Organics noted. Medium dense, olive gray, silty, fine to medium SAND with scattered fine to coarse gravel, moist. (WEATHERED TILL) ---------------------- Very dense, olive gray, silty, fine to coarse gravelly, fine to ML SM medium SAND to hard, fine to coarse gravelly. Me to medium J. sandy SILT, moist. • (VASHON GLACIAL TILL) .................................................................... Very dense, olive gray and yellowish brown, silty, fine to SM medium SAND, moist. Trace organics noted between 15 and 16.5 feel below existing ground surface. Very dense, gray to dark gray, silty, fine to medium SAND `. SM with fine to coarse gravel, moist. w U UJI z F- rn W UJ F' 0 w Lu a a a; w 0 vai NIL O 0 0 S-1 13-15-32 S-2 10-9.10 S-3 5-15-13 S-4 6-14-50/6" S-5 16-34.50/5" NS-6 30-50/51, NS-7 31-50/5' For a proper understanding of the nature of subsurface conditions, this exploration log should be read in conjunction with the text of the geotechnical report. NOTE: This tog of subsurface conditions applies only at the specified location and on the date indicated and therefore may not necessarily be indicative of other times and/or locations. Standard Penetration Test (140 lb. weight, 30" drop) ♦ Blows per foot x Lu 10 20 30 40 50 m A .............. ....:..... A.: ....... .... �... .... .... .... ....r .... ........:>> 20 40 60 sn I Water Content (%) Plastic Limit 1--0 —I Liquid Limit Natural Water Content 0 5 10 15 1 ?0 1 GEOTECHNICAL DATA REPORT BORING: SEWER REPLACEMENT ROUTE INVESTIGATION BH- 5 tMIGEOSCOENCESINC. RENTON-STONEGATE-II PAGE: 1 of 2 BORING 2007-080.GPJ 10123/08 RENTON, WASHINGTON PROJECT NO.! 2007-080-21 FIGURE' A-10 DRILLING COMPANY: Gregory Drilling Inc. LOCATION: See Figure 2 DRILLING METHOD: Truck Mounted Hollow Stem Auger DATE STARTED: 05/07/2008 SAMPLING METHOD: SPT w/Auto hammer DATE COMPLETED: 0510712008 SURFACE ELEVATION: 440 t feet LOGGED BY: T. Taddese O g U O x 00 (L O g (q U3 25 --1 1 30- 1 35 - 1 40- 1 45 - ti11Z DESCRIPTION Borehole terminated at a depth of about 30.75 feel below existing ground surface. No ground water seepage was observed during drilling. w U m z W } z rn Q Lu F w w p 'X z z 3 0 x O 0- $ O ((9 N8-8 40-5014" ® S-9 32-5013" For a proper understanding of the nature of subsurface conditions, this exploration log should be read in conjunction with the text of the geotechnical report. NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated and therefore may not necessarily be indicative of other times and/or locations. Standard Penetration Test (140 lb. weight, 30" drop) ♦ Blows per foot 1 lU 2V SV 4U OV 25 30 1 35 1 40 1 45 1 ' L 50 0 20 40 60 80 100 Water Content (%) Plastic Limit 1 0 Liquid Limit Nalural Water Content GEOTECHNICAL DATA REPORT BORING: Boil, SEWER REPLACEMENT ROUTE INVESTIGATION BH— 5 HWAGEOSCIENCES INC. RENTON-STONEGATE-11 PAGE: 2 of 2 RENTON, WASHINGTON PROJECT No., 2007-080-21 FIGURE' A-10 BORING 2007-080.GPJ 10/29/08 r-DRILLING COMPANY: Gregory Drilling Inc. LOCATION: See Figure 2 DRILLING METHOD: Truck Mounted Hollow Stem Auger DATE STARTED: 05/07/2008 SAMPLING METHOD: SPT w/Auto hammer DATE COMPLETED. 05/67/2008 SURFACE ELEVATION: 387 ! feel LOGGED BY: T. Taddese 5 I 10 2C DESCRIPTION W U of M �L r Q. Z Ln U a uu F Z a o za w x O � FO 0 a. n c(97 0r S-1 24-24-34 1 nse, gray, fine to coarse GRAVEL with fine to coarse GP d trace silt. 1 VM1 ------ (FILL)---------ofive gray to olive brown, silty, fine to coarse sandy, oarse GRAVEL, moist SM Dense, olive gray, silty, fine to medium SAND, moist. Scattered fine gravel, moist. (WEATHERED TILL) ----------------------- Very dense, olive gray, silty, fine to coarse gravelly, silty, fine :. SM to medium SAND, moist. (VASHON GLACIAL TILL) Borehole terminated at a depth of about 20.4 feet below existing ground surface. No ground water seepage was observed during drilling. S-2 10-23-25 S-3 14-14-23 S-4 32-50/3" S-5 50/3" S-6 32-50/4" S-7 23-50/4" S-8 50/6" 25 — For a proper understanding of the nature of subsurface conditions, this exploration log should be read in conjunction with the text of the geotechnical report. NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated and therefore may not necessarily be indicative of other limes andlor locations. Standard Penetration Test (140 lb. weight, 30" drop) ♦ Blows per foot x 10 20 30 40 50 0 r— 0 ....:....:....:....a....:.... ♦... . 5 10 1 15 20 I ' L 25 0 20 40 60 80 100 Water Content (°/,) Plastic Limit 1-0 Liquid Limit Natural Water Content GEOTECHNICAL DATA REPORT BORING: '1 SEWER REPLACEMENT ROUTE INVESTIGATION BH- 6 FwaosaENCESINC, RENTON-STONEGATE-II PAGE: 1 of 1 RENTON, WASHINGTON PROJECT NO.: 2007-080-21 FIGURE: A-1 BORING 2007-080.GPJ 10/29108 DRILLING COMPANY: Gregory Drilling Inc. SURFACE ELEVATION: 350.00 t feet DATE STARTED: 0510712008 DRILLING METHOD: Truck Mounted Hollow Stem Auger DATE COMPLETED: 05/07/2008 SAMPLING METHOD: SPT wlAuto hammer LOGGED BY: T. Taddese LOCATION: See Figure 2 1 5 1 10 1 15 I 20 DESCRIPTION W CoLLj W z Standard Penetration Test � Q W U I- co w v (140 lb. weight, 30'drop) W w w e Blows per toot a s ' w O w H z o n � y O rU= a.— a- a to 0 10 20 30 40 50 0 . r 0 GP Medium dense, olive gray, fine sandy, fine to coarse AGRAVEL. (FILL) SP Medium dense, brown, fine SAND. Scattered gravel, moist. (FILL/ALLUVIUM� ............................ -. -- .......................... _... Medium dense, slightly rust mottled, olive brown, fine to medium SAND. Scattered fine gravel, moist. SM Medium dense, olive gray, fine SAND with silt, moist. (ALLUVIUM) J Medium stiff, slightly rust mottled, olive brown to yellowish ML brown, SILT with fine sand, moist. Faint bedding noted. MIL Dense to hard, olive brown, silty, fine to coarse gravelly, fine SM to medium SAND to fine to coarse gravelly, fine to medium sandy, SILT, moist. (ADVANCE OUTWASH) Dense, olive brown, fine to coarse gravely, silty, fine to `. SM medium SAND, moist. .............................. .... .............. Dense, olive gray and yellowish brow, silty, fine to medium SM SAND, moist. Scattered gravel noted. Borehole terminated at a depth of about 21.5 feet below existing ground surface. No ground water seepage was observed during drilling. 25 S-1 3-5.6 S-2 2-3.4 S-3 3-7-7 S-4 2-3-3 S-5 1-13-21 S-6 11-14-19 S-7 10-18-17 0 20 40 60 80 100 Water Content (%) Plastic Limit i 0 Liquid Limit Natural Water Content NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated and therefore may not necessarily be indicative of other times and/or locations. 5 1 10 1 ib'I111111 GEOTECHNICAL DATA REPORT BORING: SEWER REPLACEMENT ROUTE INVESTIGATION BH- 7 HmaosaENM INC. RENTON-STONEGATE-11 PAGE: 1 of 1 . RENTON, WASHINGTON PROJECT NO.: 2007-080-21 FIGURE' A-1 2 PZO 2007-080.GPJ 10129/08 DRILLING COMPANY: Davies Drilling LOCATION: See Figure 2 DRILLING METHOD: Track Mounted Hollow Stem Auger DATE STARTED: 05108/2008 SAMPLING METHOD: SPT w/Cathead DATE COMPLETED: 05/0812008 SURFACE ELEVATION: 410 t feet LOGGED BY: D. Coltrane U J J F m cn 04 m C3: (n D 0 5 10 my, 20 DESCRIPTION � m w z w Standard Penetration Test a 2 Q (140 lb. weight, 30" drop) z in = FuJ o ♦ Blows per foot a a w z 3 W x Z O _ U., 0: W o°1 O a O O 0 10 20 30 40 50 0— S-1 9-5-2 f 0 Asphalt SM Cuttings: Loose, light brown, to brown, silty sand with gravel. (FILL) SM Medium dense, light brown, silty SAND with fine to coarse gravel, wood bits, rootlets, moist. (WEATHERED TILL) SM Medium dense to dense, light olive brown, silty SAND with gravel, moist. Oxide mottling noted. (VASHON GLACIAL TILL) Gravelly drilling between 6.0 to 7.0 feel. Dense to very dense, olive brown to light olive brown, silty, SM SAND with gravel, moist. Wetter zones in some of the sandier material. Very dense, olive gray, SAND with silt and gravel to silty SM SAND with gravel, moist. Driller notes less big gravels, smaller more angular gravels. S-2 3-3-12 S-3 28-2-20 SA 10-21-26 S-5 15-16-28 5-6 21-5016" S-7 5011" 25 — -------------------- For a proper understanding of the nature of subsurface conditions, this exploration log should be read in conjunction with the text of the geotechnical report. NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated and therefore may not necessarily be indicative of other limes and/or locations. M :....A....:.... ♦ ..... .... ....:....: I 20 40 60 80 100 Water Content (%) Plastic Limit 1--0— Liquid Limit Natural Water Content 5 10 1 15 1 20 1 25 I GEOTECHNICAL DATA REPORT BORING: SEWER REPLACEMENT ROUTE INVESTIGATION BH- 8 EMGEOSCIENCESINC. RENTON-STONEGATE-II PAGE: 1 of 2 RENTON, WASHINGTON PROJECT NO.: 2007-080-21 FIGURE' A-13 BORING 2007-080,GPJ 10/23108 DRILLING COMPANY: Davies Drilling LOCATION: See Figure 2 DRILLING METHOD: Track Mounted Holtow Stem Auger DATE STARTED: 05/08/2008 SAMPLING METHOD: SPT w/Calhead DATE COMPLETED: 05/08/2008 SURFACE ELEVATION: 410 t feet LOGGED BY: D. Coltrane to W U J a } 2 D v rn !n Q = J m O rn W a W a W �p �' f• O w o E 0 Z) DESCRIPTION. a$ O 25 S•8 40-50/3" SM Very dense, gray to olive gray, fine to medium SAND with silt ® and fine gravel, moist to wet. Perched water detected in sand seam. SM r Very dense, olive brown, silty SAND with gravel, moist to wet. 30 - Borehole terminated at a depth of about 30.25 feet below existing ground surface. Ground water was observed between 23 to 28 feet below existing ground surface. 35 - 40 - t6� C�' S-9 50/3" For a proper understanding of the nature of subsurface conditions, this exploration log should be read in conjunction with the text of the geotechnical report. NOTE: This fog of subsurface conditions applies only at the specified location and on the date indicated and therefore may not necessarily be indicative of other times and/or locations. Standard Penetration Test (140 lb. weight, 30" drop) ♦ Blows per foot r 1u zu Ju 4u 5u 25 30 1 35. 1 40 1 45 1 ' L 50 0 20 40 60 80 too . Water Content (%) Plastic Limit 1 19 Liquid Limit Natural Water Content GEOTECHNICAL DATA REPORT BORING: SEWER REPLACEMENT ROUTE INVESTIGATION BH- 8 HMGEOSCIENCES INC. RENTON-STONEGATE-11 PAGE: 2 of 2 RENTON, WASHINGTON PROJECT NO.: 2007-080-21 FIGURE' A-1 3 BORING 2007-080.GPJ 10129/08 :'. SM Medium dense, light brown, silty SAND with gravel, moist. Contains small wood particles. SM...............................FILL)............................. Medium dense, brown to gray brown, silty SAND with gravel, moist. Contains wood particles and trace oxide mottling. ......................................................... _.......... Medium dense, dark gray brown, silty SAND with gravel, wood SM particles, burnt wood, moist. .................................................................... Medium dense, gray to gray brown, silty SAND, moist to wet. :. , SM Trace rootlets and oxide mottling. Becomes SAND with silt at about 9 feet. ................................................................. Medium dense, light olive brown, silty SAND with gravel, `. SM moist to wet. Contains some cleaner sand seams. Perched water noted at about U5 Feet. SM Very dense, olive gray, silty SAND with gravel to trace gravel, moist. Some oxide mottling. (VASHON GLACIAL TILL) Some sand seams detected. GEOTECHNICAL DATA REPORT BORING: ' SEWER REPLACEMENT ROUTE INVESTIGATION BH- 9 1 IMGEOSCIENCES INC. RENTON-STONEGATE-II PAGE: 1 of 2 RENTON, WASHINGTON ' PROJECT NO.: 2007-080-2 1 FIGURE' A-1 4 PZO 2007-080.GPJ 10/29/08 DRILLING COMPANY: Davies Drilling SURFACE ELEVATION: 398.00 t feet DATE STARTED: 05/08/2008 DRILLING METHOD: Track Mounted Hollow Stem Auger DATE COMPLETED: 0510812008 SAMPLING METHOD: SPT w/Cathead LOGGED BY: D. Coltrane LOCATION: See Figure 2 W Co U Z U J a2 } Z H a r u � K U 0. F W W W W F- Fw- I,- U Z o = Oj o � DESCRIPTION v� vi a a 00 0. ai 0 25 SM Very dense, olive brown, silty SAND with gravel to SAND With®S-8 5015.5" sill and gravel, moist. Contains minor sand lenses which are slightly wetter. SM I Very dense, olive brown, silty SAND with gravel, mist. 1 30 - Borehole terminated at a depth of about 30.8 feet below existing ground surface. Minor perched ground water water seepage observed at an approximate depth of 13.5 feet below the existing ground surface. 1 35 - 1 40- 1 45 - 1 50 - ® S-9 39-5014" NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated and therefore may not necessarily be indicative of other times and/or locations. Standard Penetration Test (140 Ila. weight, 30" drop) ♦ Blows per fool 10 20 30 40 0 20 40 60 80 Water Content (%) Plastic Limit 1 40 Liquid Limit Natural Water Content _ W 0 25 30 1 91-M 40 1 .b� - �-50 I 100 GEOTECHNICAL DATA REPORT BORING: SEWER REPLACEMENT ROUTE INVESTIGATION BH- 9 HMGEOSaENCES INC. RENTON-STONEGATE-II PAGE: 2 of 2 RENTON, WASHINGTON PROJECT NO.: 2007-080-21 FIGURE- A'1 4 PZO 20071080.GPJ 1C29/08 DRILLING COMPANY: Gregory Drilling Inc. LOCATION: See Figure 2 DRILLING METHOD: Truck Mounted Hollow Stem Auger DATE STARTED: 05/08/2008 SAMPLING METHOD: SPT w/Auto hammer DATE COMPLETED: 06108120D8 SURFACE ELEVATION: 375 t feet LOGGED BY: T. Taddese rn rn U J_ O x O rn M 01 DESCRIPTION 0— mill 3-inch thick layer of asphalt over 3-inch thick layer of crushed SP base course. SM From 0 to 7 feet a vactor truck was used to remove the material due to utility restrictions. The material removed was observed and logged, but no samples were collected. Material consisted of Gray, gravely SAND with sill m7c 1 10- 1 15- I 20 - 25 - W U OWq Z W Ln U Z to 1- ❑ � C, 0 a s w a o ix ran ran 0 SM Medium dense, mottled gray and orangish brown, sandy SILT to silty SAND with gravel and cobbles, moist. S-1 3-3-3 [FILL] GP Very loose, gray, poorly graded fine GRAVEL with sand and S-2 2.2-1 ° trace silt, moist. oO [BEDDING MATERIAL] ° SM Very dense, light gray brown, silty SAND with gravel, moist. ® S-3 50/6 [GLACIAL TILL] Very dense, light olive gray, silty SAND with gravel, moist. I ® SA 50/5 Broken gravels in sampler. Very dense, light olive brown, silty SAND with gravel, moist. I N S-5 5015 Very dense, light olive gray, silty SAND with gravel, moist. J N S-8 50/8 Boring was terminated at 20.5 feet below ground surface. No ground water seepage was observed while drilling this exptoratory boring, Standard Penetration Test (140 lb. weight, 30" drop) ♦ Blows per foot x w� 10 20 30 40 50 ❑ w For a proper understanding of the nature of subsurface conditions, this 0 20 40 so 80 exploration log should be read in conjunction with the text of the Water Content (%) geotechnical report. Plastic Limit 1--0 Liquid Limit Natural Water Content NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated and therefore may not necessarily be indicative of other times and/or locations. 5 10 1 15 1 — ` 25 I 100 GEOTECHNICAL DATA REPORT BORING: ' 1 SEWER REPLACEMENT ROUTE INVESTIGATION BH-10 IMGEOSCIENCESINC, RENTON-STONEGATE-II PAGE: 1 of 1 RENTON, WASHINGTON PROJECT NO.: 2007-080-21 FIGURE' A-1 5 BORING 2007-080.GPJ 10/29108 _ SM (TOPSOIL) Loose, brown, silty SAND with wood pieces, rootlets, and burnt wood, SC [ALLUVIUM] Loose, light brown, clayey, fine SAND with trace gravel, moist to wet. Trace rootlets, moitted coloring noted. Medium dense, olive brown, clayey, fine SAND, with beds of day. Trace fine to coarse gravel. (RECESSIONAL OUTWASH) Medium dense to dense, brown to light brown, fine gravelly, fine to coarse SAND, to sandy, fine to medium GRAVEL. wet. Or Subrounded and subangular gravel and sand. Initial ground water seepage encountered at 7.5 feet below ground surface. Becoming silty at about 10 feet. Medium dense, brown to dark brown, fine gravelly, medium to coarse SAND with silt, wet. Dense, light brown, fine to medium sandy, fine GRAVEL with silt, mt.. 0! 'Interbed of light brown, silty, fine to medium Dense, light brown, sandy fine to medium GRAVEL With silt, wet. . Y -- - - - - - - - - - - - - - - - - - - - - - - - -- GEOTECHNICAL DATA REPORT BORING: ' ' SEWER REPLACEMENT ROUTE INVESTIGATION BH-1 1 HMGEO SCIENCES INC RENTON-STONEGATE-II PAGE: I of 2 RENTON, WASHINGTON PROJECT No.. 2007-080-21 FIGURE: A-16 PZO 2007-080.GPJ 10f29108 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 DRILLING COMPANY: Davies Drilling SURFACE ELEVATION: 320.00 i feet DATE STARTED: 05/07/2008 DRILLING METHOD. Track Mounted Hollow Stem Auger DATE COMPLETED: 05f0712008 SAMPLING METHOD: SPT w/Cathead LOGGED BY: D. Coltrane LOCATION: See Figure 2 30 - 35 - 40 - 1 45- 1 50 - o U m z y W WF z J 0 W W a s W �p M I- w 0 w W � 3 ai N D DESCRIPTION vai, 0)a o s 0 a vvi 0 Stiff, gray, sandy, g y dY, silty CLAY with trace clay beds, and trace S� 7�-9 AL ^/oF '. gravel, moist to wet. (RECESSIONAL LACUSTRINE) S-9 7-9-9 AL '. Interbed of clayey fine to medium SAND with rootlets, wet. — %F I/S Medium dense, gray, sandy CLAY, moist to wet Laminar S-10 5-6-8 GS bedding, trace gravel. Medium dense to dense gray, sandy CLAY with trace gravel 5.11 7-14-17 GS and interbeds of sandy clay, mast to wet. Laminar bedding. — Shelby tube sample driven 23 inches. S-12a 0-6" Dark gray, clayey SAND, moist. S•121b 6-16" Dark gray, poorly graded SAND wilh Gay, moist. 16-23" Dark gray, poorly graded SAND with clay and gravel, S-12c mist. Medium dense, gray, clayey SAND with trace gravel, mist. S-13 11-12-22 GS Stiff, gray sandy silly CLAY with gravel, moist. CL ML S-14 5-10-12 AL Borehole terminated at a depth of about 41.5 feet below existing ground surface. Ground water seepage was encountered at 7.5 feet below the ground surface during the exploration. A piezometer was installed in the exploration with screen from 25-35 feet below ground surface. NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated and therefore may not necessarily be indicative of other times and/or locations. Standard Penetration Test (140 lb. weight, 30" drop) ♦ Blows per foot w—', 20 30 40 50 0 r 25 A . .. A ....................:........1 �— 30 1 • : A 36 .......... .................. I l-45 1 — 50 0 20 40 60 80 100 Water Content (%) Plastic Limit 1--0 Liquid Limit Natural Water Content GEOTECHNICAL DATA REPORT BORING: SEWER REPLACEMENT ROUTE INVESTIGATION BH-11 I-ImaosaENCES INC. RENTON-STONEGATE-II PAGE: 2 of 2 RENTON, WASHINGTON PROJECT No.: 2007-080-21 FIGURE: A-16 PZO 2007-M.GPJ 10/29/08 DRILLING COMPANY: Davies Drilling LOCATION: See Figure 2 DRILLING METHOD: Track Mounted Hallow Stem Auger DATE STARTED: 05/07/2008 SAMPLING METHOD: SPT w/Calhead DATE COMPLETED: 05/07/2008 SURFACE ELEVATION: 319 t feet LOGGED BY: D. Coltrane W. �r tt W4 DESCRIPTION 03 w U Standard Penetration Test a- 2 y G N 4 (140 lb. weight, 30" drop) z (0 Fw o ♦ Blows per foot a a o y 3 w Z _ r ran o a a �. O of 0 uu � 0 10 20 30 40 50 S-1 3-2-3 r-0 :. SM [TOPSOIL] Loose, brown, silty, SAND, with gravel. Contains pockets of light brown, silty sand, with wood pieces, and rootlets. °• (ALLUVIAL SANDS AND GRAVELS) Medium dense to very dense, grayish brown to brown, .o - 6.0. gravelly SAND with silt, moist. Sample driven on rock. o Silt content increases. O Very dense, dark brown, poorly graded GRAVEL with sand as and silt, moist. Sample driven on rock. Wood pieces/twigs A . noted. Sand becomes fine to coarse and gravel becomes fine. .o a o , Medium dense, brown, sandy GRAVEL with silt, wet. Sampler .0 wet at 7.5 feet. Gravel is rounded to sub -rounded. o 8 (RECESSIONAL OUTWASH) Dense, dark yellowish broom, well graded GRAVEL with sand, wet. Sub -angular gravel is present. °.;:• " Medium dense, brown, sandy well graded GRAVEL, with silt, rj] wet. Becomes sillier at about 16.0 feet. Some heave in sample. I�Ily�l Gravel is sub -rounded to sub -angular. 0 GM Dense, gray, silty GRAVEL with medium to coarse sand, wet. Gravel is sub -angular to sub -rounded. Drilling becomes less -T gravelly at 22 feet below ground surface. ML Medium dense, gray, sandy SILT, moist to wet. (RECESSIONAL LACUSTRINE) S-2 10-27-25 S-3 13-50/5" GS Q S-4 7-8-12 1 8-5 19-12-20 GS S-6 11-13-15 S-7 20-23-24 25 For a proper understanding of the nature of subsurface conditions, this exploration log should be read in conjunction with the text of the geotechnical report. NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated and therefore may not necessarily be indicative of other times and/or locations. 11. 20 40 60 80 too Water Content (%) Plastic Limit 1--0 Liquid Limit Natural Water Content 5 10 1 15 1 20 1 GEOTECHNICAL DATA REPORT BORING: 1 SEWER REPLACEMENT ROUTE INVESTIGATION BH-12 HWAGEOSCIENCES INC RENTON-STONEGATE-I I PAGE: 1 of 2 RENTON, WASHINGTON PROJECT NO.: 2007-080-21 FIGURE' A-17 BORING 2007.080.GPJ 10/29/08 DRILLING COMPANY: Davies Drilling LOCATION: See Figure 2 DRILLING METHOD: Track Mounted Hollow Stem Auger DATE STARTED: 05/07/2008 SAMPLING METHOD: SPT w/Cathead DATE COMPLETED: 05/07/2008 SURFACE ELEVATION: 319 t feet LOGGED BY: D. Coilrane 1 30 I 35 1 4( 1 45 DESCRIPTION w a. } U of F- = U L $ U w w w z a a o ; w o a$ O of Very stiff, gray, sandy SILT, moist. Contains scattered layers of sill/clay at about 25.0 feet. Stiff, gray, SILT with sand, moist. SM Medium dense, gray, silty SAND with gravel, wet. (RECESSIONAL OUTWASH) T. Silt content decreases at about 30.5 feet. Medium dense, gray, fine to medium SAND, with silt, wet. Interbeds of sillier sand from about 32.5 to 33 feet. SP No Sample recovery from this depth. Drilling action was SM consistent with the recessional outwash material encountered 4. from 30 to 34 feet below ground surface. 5 feet of heave noted from about 35 to 40 feet. p No sample recovery. Blow counts most likely accurate. No sample recovery. Blow counts most likely affected by heave. O Borehole terminated at a depth of about 41.5 feet below existing ground surface. Ground water seepage was observed at a depth of approximately 7.5 feet below the existing ground surface and measured at 8.0 feet below ground surface after the removal of the casing. S-8 6-10-10 GS S-9 6-7-8 %F S-10 14-12.6 GS S-11 9-6-14 %F S-12 3-9-11 S-13 1-12-3 50--J For a proper understanding of the nature of subsurface conditions, this exploration log should be read in conjunction with the text of the geotechnical report. NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated and therefore may not necessarily be indicative of other times and/or locations. Standard Penetration Test (140 lb. weight, 30" drop) A Blows per foot �.......:....:.... . ..I 0 20 40 60 80 Water Content (%) Plastic Limit 1-0 Liquid Limit Natural Water Content f— 45 1 J L 50 100 GEOTECHNICAL DATA REPORT BORING: SEWER REPLACEMENT ROUTE INVESTIGATION BH-12 HMGEOSCIENCESINC. RENTON-STONEGATE-II PAGE: 2 of 2 RENTON, WASHINGTON PROJECT No.: 2007-080-21 FIGURE: A-17 BORING 2007-080.GPJ 10/2910B -\3-4" thick layer of asphalt. Light brown gravelly SAND to sandy GRAVEL, moist. From cuttings. [FILL] Asphaltic —gravel —chunks, —(A—TB—) 17 plugin thickness. - - - - - - - - - - - - - - - - - - - - - SM No recovery. - - - - - - - - - - - - - - - - - - - - - [RECENT ALLUVIUNQ SM Medium dense, light brown, silty SAND with gravel, moist. Fine to medium angular gravel, fine to coarse sand. Medium dense, light brown, silty SAND with gravel. moist. Fine to medium angular gravel, fine to coarse sand. Medium dense, light brown, silty SAND with gravel, moist. Fine to medium angular gravel, fine to coarse sand. Medium dense, light brown, silty SAND with gravel, moist. Fine to medium angular gravel, fine to coarse sand. Ground water encountered at 15.0 feet below the ground surface. Aj- Medium dense, light brown, silty SAND with gravel, moist to wet. Fine to medium angular gravel, fine to coarse sand. GEOTECHNICAL DATA REPORT BORING: SEWER REPLACEMENT ROUTE INVESTIGATION BH-1 3 HMGEOSCIENCES INC RENTON-STONEGATE-11 PAGE: 1 of 2 RENTON, WASHINGTON PROJECT NO. 2007-080-21 FIGURE A-18 PZO 2007-080.GPJ1 10129/08 DRILLING COMPANY: Holocene Drilling SURFACE ELEVATION: 328.00 t feet DATE STARTED: 09/11/2008 DRILLING METHOD: Truck Mounted B-59 Hollow Stem Auger DATE COMPLETED: 09111/2008 SAMPLING METHOD: SPT w/Autohammer LOGGED BY: D. Coltrane LOCATION: See Figure 2 O V) g U J J O u) rid ca U Ww U) 20— 1 25 X 1 35 1 40 DESCRIPTION W U W Coz� j r~j� In W U i}a' W W W ~ g a. a o w 0w a.. � a O v a ji 0 S•8 8-8-10 F—FT-,{ Medium dense, light brown, silty SAND with gravel, moist to j. wet. Fine to medium angular gravel, fine to coarse sand. Medium dense, light brown, interbedded, silty SAND with gravel, and SAND with sill and gravel, moist to wet. SAND with sift and gravel is wet. SP SM Medium dense, light brown to reddish brown, becoming gray at the tip of the sampler, fine to medium SAND with silt, wet. CL [RECESSIONAL LACUSTRINE DEPOSITS] Very stiff, gray to light gray, sandy lean CLAY to lean CLAY with sand, moist to wet. Boring was terminated at 31.5 feet below the ground surface. Ground water seepage was observed at 15.0 feet below the ground surface. Interbedding of the alluvial deposits resulted in layers of material of varying permeability. S-9 4-6-9 3.10 11-13-13 5-11 2-8-11 0 NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated and therefore may not necessarily be indicative of other times and/or locations. Standard Penetration Test (140 lb. weight, 3U' drop) ♦ Blows per foot x w 10 20 30 40 50 r— 20 -25 1 - 30 1 - 35 1 ' L-40 20 40 60 80 100 Water Content (%) Plastic Limit 1--0 — 1 Liquid Limit Natural Water Content GEOTECHNICAL DATA REPORT BORING: SEWER REPLACEMENT ROUTE INVESTIGATION BH-13 HmaosaENCESINC. RENTON-STONEGATE-II PAGE: 2 of 2 RENTON, WASHINGTON PROJECT NO.: 2007-080-21 FIGURE: A-1 8 PZO 2007-080.GPJ 1CI29108 I -\3-4" thick layer of asphalt. Grayish brown gravelly SAND to sandy GRAVEL, moist. from cuttings. ---------- [FILL] Loose, brown, silty SAND with gravel, moist. Asphaltic gravel chunks, (ATS) 2" plug in sampler, unknown SM I thickness . . . . . . . . . . . . . . . . . . [RECENT ALLUVIUM] Medium dense, light brown, silty SAND with gravel, moist. Fine to medium angular gravel, fine to coarse sand. No recovery. O Medium dense, light brown, silty SAND with gravel, moist. Fine to medium angular gravel, fine to coarse sand. Ground water encountered between 12.5 and 15 feet below ground surface. S-6A 15-16 feet BGS. Stiff, light brown, thinly laminated, SILT with oxide mottling streaks, moist. S-6B 16-16.5 feet BGS. Medium dense, light brown, silly GRAVEL with sand, wet. GEOTECHNICAL DATA REPORT BORING: ' ' SEWER REPLACEMENT ROUTE INVESTIGATION BH-14 HMGj0SaENCES INC RENTON-STONEGATE-II PAGE: I of 2 RENTON, WASHINGTON PROJECT NO.: 2007-080-21 FIGURE: A-19 BORING 2007-M.GPJ 10/29M DRILLING COMPANY: Holocene Drilling LOCATION: See Figure 2 DRILLING METHOD: Truck Mounted B-59 Hollow Stem Auger DATE STARTED: 09/11/2008 SAMPLING METHOD: SPT w/Autohammer DATE COMPLETED: 09/11/2008 SURFACE ELEVATION: 328 t feet LOGGED BY: D. Coltrane Wk 3C 35 DESCRIPTION mz w w Standard Penetration Test C (140 lb. weight, 30" drop) z .__ F o ♦ Blows per foot a a W �� w z H w—�° F of w�' rn rn Q. O CO 0 10 20 30 40 50 O w Medium dense, light brown, silty SAND with gravel, moist to wet. Fine to medium angular gravel, fine to coarse sand. Alternating zones of sillier and sandier material. Medium dense, light brown, silty SAND with gravel, moist to wet. Fine to medium angular gravel, fine to coarse sand. Alternating zones of siitier and sandier material. CL [RECESSIONAL LACUSTRINE DEPOSITS] Very stiff, gray to light gray, sandy lean CLAY to lean CLAY with sand, moist to wet. Boring was terminated at 31.5 feet below the ground surface. Ground water seepage was observed at 15.0 feet below the ground surface. Interbedding of alluvial deposits resulted in layers of material of varying permeability. S-7 8-11-13 S-8 3-7-15 S-9 4-6.7 40 —J For a proper understanding of the nature of subsurface conditions, this exploration log should be read in conjunction with the text of the geotechnical report. NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated and therefore may not necessarily be indicative of other times andfor locations. F— 20 E— 35 1 "40 0 20 40 60 80 100 Water Content (%) Plastic Limit 1--0 --1 Liquid Limit Natural Water Content :..�...� ... .... ................ GEOTECHNICAL DATA REPORT BORING: SEWER REPLACEMENT ROUTE INVESTIGATION BH-14 HmaosaENCES INC RENTON-STONEGATE-11 PAGE: 2 of 2 RENTON, WASHINGTON PROJECT NO.: 2007-080-21 FIGURE- A-1 9 BORING 2007-M.GPJ 10f29108 APPENDIX B LABORATORY TESTING 1 "I APPENDIX B LABORATORY TESTING Laboratory tests were conducted on selected soil samples to characterize relevant engineering and index properties of the site soils. Laboratory testing, as described below, consisted of determining moisture content, grains size distribution and Atterberg Limits. All laboratory testing was completed in general accordance with ASTM (American Society of Testing Materials) specifications. Moisture Content Testing The moisture content for select samples collected from the explorations was determined in general accordance with ASTM D 2216. The results are shown at the sampled interval on the appropriate boring logs in Appendix A. Grain Size Distribution Grain size distribution was determined for selected samples in general accordance with ASTM D-422. Results of these analyses are plotted on Figures 13-1 through B-8. ' Liquid Limit, Plastic Limit, and Plasticity Index of Soils (Atterberg Limits) Selected samples were tested using method ASTM D 4318, multi -point method. The ' results are reported on the attached Liquid Limit, Plastic Limit, and Plasticity Index reports found on Figure B-9. U.S. STANDARD SIEVE SIZES 3" 1-1/2" 3/45/8" 3/8" #4 #10 #20 #40 #60 #100 #200 100 I I I I I I I I I I I I I I I I I 90 I 1 1 I ! I f I 80 70 m 60 Lu 50 Z LL 1— 40 Z w I I I 1 i I I i I C) 30 W I { I I I 1 I I I ! 20 I 10 t I I I I I ! I I I I 0 I 50 10 5 1 0.5 0.1 0.05 0.01 0.005 0.001 0.0005 GRAIN SIZE IN MILLIMETERS GRAVEL GRAVEL SAND SILT CLAY Coarse Fine Coarse Medium Fine SYMBOL SAMPLE DEPTH (ft) CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name % MC LL PL PI Gravel Sand Fines ® BH- 1A S-3 4,5 - 6.0 {SM} Olive gray, silty SAND with gravel 10 16.5 45.4 38.1 ® BH-.1B S-4 7.5 - 8.9 {SM} Olive gray, silty SAND 11 14.0 43.1 42.9 ® BH- 3A S-3 4.0 - 5.5 {SM} Strong brown, silty SAND with gravel 12 16.2 50,2 33.6 REN`�"ON-STONEGATE-11 METHO©ASTM D422 RENTON, WASHINGTON GEOTECHNICAL DATA REPORT PARTICLE -SIZE ANALYSIS �E®SCIENCES INC. 1 SEWER REPLACEMENT ROUTE INVESTIGATION OF SOILS ® PROJECT NO.: 2007-080-21 FIGURE: B-� HWAGRSZ 2007-080.GPJ 10/29/08 REN`�"ON-STONEGATE-11 METHO©ASTM D422 RENTON, WASHINGTON GEOTECHNICAL DATA REPORT PARTICLE -SIZE ANALYSIS �E®SCIENCES INC. 1 SEWER REPLACEMENT ROUTE INVESTIGATION OF SOILS ® PROJECT NO.: 2007-080-21 FIGURE: B-� HWAGRSZ 2007-080.GPJ 10/29/08 iiII{fIIiIilIIIIIf l VtEIIt!IItItIIIIIl EL SAND IIIIIIIiiiIfII(II tIIIIIIIIIIIII! lIIIIIIIIII1I 1I!I!!!IIII SILT CLAY U.S. STANDARD SIEVE SIZES 3/4' 3" 5/8" 3/8" #4 #10 #20 #40 #60 #100 #200 100 90 zzzzz 80 70W60 ppW 50 Z1— 40 ZW30w20 10Ll I I 1 1. 1 1 1 1 1 50 10 5 1 0.5 0.1 0.05 0.01 0.005 0.001 0.0 005 GRAIN SIZE IN MILLIMETERS Gravel Sand Fines GRA Coarse Fine Coarse Medium Fine SYMBOL SAMPLE DEPTH (f#) CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name % MC LL PLpl ® BH-46 5-4 7.5-8.9 (SM) Light grayish brawn, silty SAND with gravel 7 23.9 47.3 IN BH-5 S-5 10.0 - 11.4 (SM) Yellowish brown, silly SAND 10 10.1 49.8 . ® BH-5 S-9 30.0-30.8 (SM) Gray, silty SAND 8 10,8 48.2 41.0 GRA Coarse Fine Coarse Medium Fine SYMBOL SAMPLE DEPTH (f#) CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name % MC LL PLpl ® BH-46 5-4 7.5-8.9 (SM) Light grayish brawn, silty SAND with gravel 7 23.9 47.3 IN BH-5 S-5 10.0 - 11.4 (SM) Yellowish brown, silly SAND 10 10.1 49.8 . ® BH-5 S-9 30.0-30.8 (SM) Gray, silty SAND 8 10,8 48.2 41.0 SYMBOL SAMPLE DEPTH (f#) CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name % MC LL PLpl ® BH-46 5-4 7.5-8.9 (SM) Light grayish brawn, silty SAND with gravel 7 23.9 47.3 IN BH-5 S-5 10.0 - 11.4 (SM) Yellowish brown, silly SAND 10 10.1 49.8 . ® BH-5 S-9 30.0-30.8 (SM) Gray, silty SAND 8 10,8 48.2 41.0 U.S. STANDARD SIEVE SIZES 11 3/4 3" 1-112" 5/8" 3/8, #4 #10 #20 #40 #60 #100 #200 I 100 90 I I I I I I I ! I I ! I I 80 I l l I I I I ! I I-- I I I I I I 1 ! w 70 I I I I f ! I ! I ! m 60 50LL I I I Z I I I I I I I I I I I I I I 40 Z W C) w 30 a I I I - I I I I I 20 I I I I I ! I I ! 10 I I I I I I ! I I 0 I I I I I I I I I I 50 10 5 1 0.5 0.1 0.05 0.01 0.005 0.001 0,0005 GRAIN SIZE IN MILLIMETERS .SYMBOLSAMPLE DEPTH (ft) CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name % MC LL PL PI Gr0 veI Sand Fines ® BH- 7 S-3 7.5 - 9.0 (SM) Brown, silty SAND 24 0.8 79.8 19.3 ® BH- 7 S-4 10.0 - 11.5 (ML) Yellowish brown, SILT with sand 23 0.0 72.9 A Bt1- 7 S-7 20.0 - 21.5 (SM) Yellowish brown, silty SAND 8 0.0 12.7 GRAVEL SAND SILT .CLAY Coarse Fine Coarse Medium Fine U.S. STANDARD SIEVE SIZES 3" 1-1 /2" 3/4" ' 5/8" 3/8" . #4 #10 #20 #40 #60 #100 #200 100 90 80 1 2 70 w } 60 m L� W 50 ti F— 40 Z W 30 W t1. 20 10 0 05 GRAIN SIZE IN MILLIMETERS SYMBOL SAMPLE DEPTH (ft) CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name % MC LL PL pj Gravel Sand Fines GRAVEL SAND SILT CLAY Coarse Fine Coarse Medium Fine ® BH-11 S-3 5.0 - 6.5 (SC) Olive brown, clayey SAND 19 29 18 11 0.0 35.7 ® BH-11 S-8 25.0 - 26.5 (CL-Ml.) Gray, sandy silty CLAY 20 23 17 6 0.0 65.0 ® BH-11 S-9 27.5 - 29.0 (SC) Gray, clayey SAND 16 22 13 9 0.0 42,3 .. ....... ..... . ........ ........... 01 Eli i...... .. ... 50 10 5 1 0.5 0.1 . 0.05 GRAIN SIZE IN MILLIMETERS 0.01 0.005 0.001 0.0005 SYMBOL SAMPLE DEPTH (ft) CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name % MC ILL PL PI Gravel Sand Fines ® BH-11 S-10 30.0 - 31.6 (CL) Gray, sandy CLAY 17 9.6 36.6 53.8 ® BH-11 S-11 32.5 - 34.0 (CL) Gray, sandy CLAY 21 0.0 65.2 A BH-11 S-13 37.5 - 39.0 (SC) Gray, clayey SAND 22 7.3 48.7 44.1 GEOTECHNICAL DATA REPORT PARTICLE -SIZE ANALYSIS SEWER REPLACEMENT ROUTE INVESTIGATION OF SOILS RENTON-STONEGATE-II METHOD ASTM D422 GEOSCIENCES INC. RENTON, WASHINGTON PROJECT NO.: 2007-080-21 FIGURE: B-5 HWAGRSZ 2007-080.GPJ 10/29/08 .4 :01 2 2 70 W �- 60 M W 50 I— 40 W �30 W 0. 2C 1c c GRAVEL SAND SILT CLAY Coarse Fine Coarse Medium I Fine �, U.S. STANDARD SIEVE SIZES 1 1/2" 3/4518" - 3/8" #4 #10 #20 #40 #60 #100 #200 Ino III aim n GRAIN SIZE IN MILLIMETERS SYMBOL SAMPLE DEPTH (ft) CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name % MC LL Pt_ PI Gravel Sand Fines ® BH-11 S-14 40.0 - 41.5 (CL-ML) Gray, sandy silty CLAY 18 22 15 7 0.0 57.1 ® BH-12 S-3 5.0 - 6.0 (GP -GM) Dark brown, poorly graded GRAVEL with sand and silt 10 56.6 35.0 8.4 ® BH-12 S-5 10.0 - 11.5 (GW) Dark yellowish brown, well graders GRAVEL with sand 11 67.3 30.1 2.6 105 GEOTECHNICAL DATA REPORT PARTICLE -SIZE ANALYSIS =A SEWER REPLACEMENT ROUTE INVESTIGATION OF SOILS RENTON-STONEGATE—II METHOD ASTM D422 I A.GEOSCIENCES INC. RENTON, WASHINGTON PROJECT NO.: 2007-080-21 FIGURE: B-6 HWAGRSZ 2007-OSO.GPJ/0/29108 U.S. STANDARD SIEVE SIZES 3/41 3" 1-1/2" 5/8" 3/8" #4 #10 #20 #40 #60 #100 #200 100' 90 $o 2 70 W m 60 DC W 50 U- (— 40 W 30 W11 Ell Eli -10'. 1111101111111IN11111 20 10 0 05 GRAIN SIZE IN MILLIMETERS SYMBOL SAMPLE DEPTH (ft) CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Narne % MC LL PL pl Gravel Sand Fines GRAVEL SAND SILT CLAY Coarse Fine Coarse Medium Fine i ii■w ® Bf-i-12 S-8 25.0 - 26.5 (ML) Gray, sandy SILT 23 0.0 35.7 64.3 ElBI-i-12 S-9 27.5 - 29.0 (ML) Gray, SILT with sang 27 0.0 71.4 ® BH-12 S-10 30.0 - 31.5 (SM) Gray, silty SAND with gravel 18 16.3 63.1 20.6 �1 U.S. STANDARD SIEVE SIZES 3" 1-112" 3 518" 3/8" #4 #10 #20 #40 #60 #100 #200 100 90 .80 2 70 W } 60 m W 50 LL E— 4a z w U 30 of � 20 Ills IN Ili 10 Q 05 GRAIN SIZE IN MILLIMETERS GRAVEL GRAVEL SAND SILT CLAY SYMBOL SAMPLE DEPTH (ft) CLASSIFICATION OF SOIL-.ASTM D2487. Group Symbol and Name % MC LL PL PI Grave! Sand Fines % 0 0 ® BH-12 S-11 32.5 - 34.0 (SM) Gray, silty SAND 22 0.0 23.9 ® BH-13 S-11 30.0 - 31.5 (CL) Olive gray, lean CLAY with sand 22 37 21 16 0.0 76.9 A,BH-14 S-1 2.5 - 4.0 (SM) Grayish brown, silty SAND 9 27.9 58.4 13.7 GEOTECHNICAL DATA REPORT PARTICLE -SIZE ANALYSIS SEWER REPLACEMENT ROUTE INVESTIGATION OF SOILS OVA ��7 RENTON-STONEGATE-II METRO®ASTM ®422 GE�SCIEI�dCES 1J.V� RENTON, INASHINGTON PROJECT NO.: 2007-080--21 FIGURE: B-8 HWAGRSZ 2007-080.GPJ 10/29/08 GEOTECHNICAL DATA REPORT PARTICLE -SIZE ANALYSIS SEWER REPLACEMENT ROUTE INVESTIGATION OF SOILS OVA ��7 RENTON-STONEGATE-II METRO®ASTM ®422 GE�SCIEI�dCES 1J.V� RENTON, INASHINGTON PROJECT NO.: 2007-080--21 FIGURE: B-8 HWAGRSZ 2007-080.GPJ 10/29/08 60 CL CH 50 X 40 W Z_ 30 U 20 CLfil ;/000 10 CL-ML ML MH 0 0 20 40 60 80 100 LIQUID LIMIT (LL) SYMBOL SAMPLE DEPTH (ft) CLASSIFICATION % MC LL PL PI % Fines ® BH-11 S-3 5.0 - 6.5 (SC) Olive brown, clayey SAND 19 29 18 11 35.7 ® BH-11 S-8 25.0 - 26.5 (CL-ML) Gray, sandy silly CLAY 20 23 17 6 65.0 ® BH-11 S-9 27.5 - 29.0 (SC) Gray, clayey SAND 16 22 13 9 42.3 O 1311-11 S-14 40.0 - 41.5 (CL-ML) Gray, sandy silty CLAY 18 22 15 7 57.1 ❑ BH-13 SA 1 30.0 - 31.5 (CL) Olive gray, lean CLAY with sand 22 37 21 16 76.9 GEOTECHNICAL DATA REPORT LIQUID LIMIT, PLASTIC LIMIT AND gooSEWER REPLACEMENT ROUTE INVESTIGATION PLASTICITY INDEX OF SOILS GE®SCIENCES INC. RENTON-STONEGATE-11 METHOD ASTM D4:318 RENTON, WASHINGTON B PROJECT NO.: 2007-080-21 FIGURE: -9 HWAATTB 2007-080.GPJ 10/29108 Appendix F R E N T O N Stonegate II Facility Evaluation Appendix F 1 Preliminary Building Code Review (Kennedy/Jenks Consultants) 1 1 1 1 1 ' H Rotill 6 Stonegate II Sewer System Improvements City of Renton, Washington PRELIMINARY BUILDING CODE REVIEW STONEGATE LIFT STATION Section 1 - Summary 1.01 - Description Kennedy/Jenks Consultants The Project involves the construction of a new Lift Station as part of the City of Renton Stonegate II Sewer System Improvements. The proposed facility includes a 600 square foot (sf) below -grade wet well (Lift Station), 70 sf below - grade Valve Vault, 200 sf wood -framed or CMU Control Building housing electrical equipment and controls, and a standby diesel engine generator set (genset) housed in an acoustic enclosure. The following review is a general assessment of the Building Code, and Fire and Life Safety issues as they relate to the design and location on the site of the facility. ' 1.02 - Codes Used for the Review • International Building Code (IBC), 2006 with the State of Washington 2007 Amendments ' • International Fire Code (IFC), 2006 with the State of Washington 2007 Amendments • International Plumbing Code (IPC), 2006 with the State of Washington 2007 Amendments ' • International Mechanical Code (IMC), 2006 with the State of Washington 2007 Amendments • National Electrical Code (NEC), 2005 ' • State of Washington Energy Code, 2007 • Washington Industrial Safety and Health Act (WISHA) ' 1.03 - Code Requirement Issues The State of Washington Amendments to the IBC is used for all building design requirements ' (including referenced IFC sections), and supersedes National Fire Protection Association (NFPA) requirements in all areas. As a general rule, the NFPA requirements are used for electrical design and for items that are not addressed in the IBC. ' The National Electrical Code is enforced by the City of Renton within the City limits. 1.04 - Zoning The project site is zoned R-1, Residential. A conditional use permit may be required. Local zoning ordinances can have an effect the design of the facility. Some of these design requirements include Height, Setback, Lot Coverage, Landscaping, Fencing, Lighting, Noise, Building Materials, and Off -Street Parking. Potentially critical zoning issues are addressed in Section 3.13 of ' this review. ' Preliminary: 13 June 2008 K/J Project: 0897003 By: Greg Robley Page 1 of 5 Stonegate II Sewer System Improvements City of Renton, Washington 1.05 - Code Officials Kennedy/Jenks Consultants • Planning & Permitting: City of Renton Development Services, 425-430-7200 • Fire Department Plans Review: Corey Thomas, 425-430-7024 1.06 - Synopsis of Code Analysis A detailed code discussion, references, and additional requirements are listed in Sections 2 and 3. Lift Station and Valve Vault (below -grade): Note: the Lift Station and Valve Vault are not addressed in the remainder of the review since it is not a building. • Construction: Type II-B ' • Total Area: Lift Station - approximately 600 square feet x 26 feet deep. Valve Vault - approximately 70 square feet x 10 feet deep. • Occupancy: Spaces are not inhabitable and are covered by WISHA requirements. • The below -grade structures are considered confined spaces and will be accessible by ladders. ' • The below -grade structures must be mechanically ventilated per the NFPA. Control Building ' • Construction: Type V-B • Occupancy: Moderate hazard industrial occupancy, F-1 • Total Area: Approximately 200 square feet Allowable • area: 8,500 base SF ' • Exterior walls: Non -rated, more than 10 feet from property line Occupancy • separations: None • Calculated Occupant load: 2 ' Exits required: 1 • Insulation: Required in heated and cooled areas • Sprinklers: Not Required • Stand-by Power: Required ' • Fire Alarm: Not Required • Smoke Detection System: Required by Fire Marshal ' Preliminary: 13 June 2008 K/J Project: 0897003 By: Greg Robley Page 2 of 5 Stonegate II Sewer System Improvements Kennedy/Jenks Consultants ' City of Renton, Washington • Hydrant Fire flow Requirement: 1,500 gpm and a maximum of 250 feet from building I I Section 2 - Chemical Storage Quantities and General Storage Requirements 2.01 - Standby Genset Fuel Storage The standby genset stores fuel in an integral, double -walled, sub -base fuel tank. • Diesel Fuel: Approximately 250 gallons stored in a single tank; CAS No. 000126-00-0. (NFPA/IFC Health and Flammability Ratings: H2, F2) Classified per IFC as a Combustible Liquid (Class 2) category. There are no limits on the allowable quantity of outdoor storage. Per the IFC, the diesel tank is required to be a minimum 15 feet away from property lines and 5 feet from buildings or edge of public ways. 2.02 - Chemical Separation The diesel tank is required to be separate from other chemical storage areas. 2.03 - Spill Control and Secondary Containment Required for diesel fuel tank. 2.04 - Liquid Level Limit Controls Tanks containing hazardous liquids in excess of 500 gallons shall be equipped with a liquid level limit control to prevent tank overfilling (IFC 2704.8). Section 3 - Life -Safety Analysis 3.01 - Facility Area Summary The facility includes the following spaces: • Lift Station: 600 SF below -grade structure • Valve Vault: 70 SF below -grade structure • Control Building: 200 SF, F-1 Occupancy 3.02 - Occupancy Group and Occupant Load Control Building: • F-1 Occupancy is a moderate -hazard industrial occupancy. • The calculated occupant load for the Control Building is 2. 3.03 - Physical and Health Hazards Diesel fuel is a hazardous material. Required provisions as indicated in Section 2 of this review. ' Preliminary: 13 June 2008 K/J Project: 0897003 By: Greg Robley Page 3 of 5 L Stonegate II Sewer System Improvements City of Renton, Washington 3.04 - Construction Type Kennedy/Jenks Consultants The Control Building meets the requirements of IBC Type V-B construction. Type V-B buildings can be constructed of any materials approved by the IBC. ' 3.05 - Fire Sprinklers Sprinklers are not required in the Control Building. ' 3.06 - Construction Requirements based on location to Property Lines: Based on construction type and occupancy of the Control Building, exterior walls must be one -hour protected if less than 10 feet from a property line and 2 hours if less than 5 feet from a property line. Openings in exterior walls (windows and doors) must be protected when less than 20 feet from a property line and openings are not permitted less than 3 feet. • East side (street frontage): The Control Building is located approximately 63 feet from the property line along the street frontage. ' • North side: The Control Building is located approximately 15 feet from the property line. Any openings on this side of the building must be protected. ' • West side: The Control Building is located approximately 32 feet from the property line. • South side: The Control Building is located approximately 124 feet from the property line. 3.07 - Exits ' One exit door is required from the Control Building based on occupant load. The required exit doors are 36 inches wide by 80 inches high minimum, swinging type. No special hardware (panic devices) is ' required and the exit door need not swing out in the direction of egress. 3.08 - Safety Features • Exit illumination is required at one -foot candle (IBC 1006.1). Standby power is required. (IBC 1006.1). ' 3.09 - Ventilation The Control Building may be heated and cooled by mechanical means. ' 3.10 - Building Insulation If the heating requirements for the Control Building are greater than 8 BTUs per hour per square foot; ' the Control Building will be considered a heated space per section 1310 of the State of Washington Energy Code and require building insulation as follows: ' • R-30 roof insulation. • R-11 wall insulation. 1 ' Preliminary: 13 June 2008 K/J Project: 0897003 By: Greg Robley Page 4 of 5 Stonegate II Sewer System Improvements Kennedy/Jenks Consultants ' City of Renton, Washington 3.11 - Electrical ' Electrical design shall comply with the NEC. A minimum of 42-inch clearance is required in front of panels. 3.12 - Handicap Access ' • The Control Building is normally unoccupied. Operation and maintenance personnel enter only periodically to perform operation/maintenance tasks. ' • The Control Building is not required to meet accessibility requirements. The Washington State Amendments to the IBC indicates that all facilities that are normally occupied must be accessible to the physically handicapped. Exceptions to this include areas such as equipment spaces, attics, ' crawl spaces, and similar spaces. The Control Building is considered an equipment space. 3.13 - Special Design Considerations ' • Noise from operation of the genset will be difficult to mitigate. An acoustic enclosure and exhaust silencer will be provided to reduce the noise level. The City of Renton requires that noise be limited to 45 dBA at the nearest property line. ' Preliminary: 13 June 2008 K/J Project: 0897003 By: Greg Robley Page 5 of 5 Appendix G ---------------- RENTON Stonegate II Facility Evaluation Appendix G Preliminary Structural Evaluation (Ke.nnedy/Jenks Consultants) RothHill Kennedy/Jenks Consultants ' 13 June 2008 ' Memorandum e orandum 1 To: Ryan Ray, P.E. From: Eric Tam Subject: Renton Stonegate Lift Station - Preliminary Structural Evaluation K/J 0897003 This memorandum provides background information and design requirements related to preliminary structural engineering of the City of Renton (City) Stonegate Lift Station. Project Description The Stonegate Lift Station project consists of a below -grade wet well (Lift Station) and Valve Vault, a Control Building, an above -grade standby diesel engine -generator set (genset) and an above grade electrical transformer. The Lift Station will be a cast -in -place, reinforced concrete tank, with a storage volume of 90,000 gallons. The below -grade inside dimensions of the Lift Station are approximately 20 feet (ft) by 30 ft by 26 ft deep. The above -grade Control Building, with dimensions of 20 feet by 10 feet, will be a single story, wood -framed or concrete masonry wall building. It will have a room to house electrical equipment. Adjacent to the Control Building, a new genset will be provided on in a stand-alone sound attenuating enclosure installed on a concrete slab. The electrical transformer will also be installed on a concrete slab. General Design Requirements This section prescribes structural design requirements applicable to the Lift Station, Valve Vault, Control Building, and other structures. All elements of the structures should be designed using allowable stress design, strength design, or load and resistance factor design. Allowable stress design is a method of proportioning structural elements such that computed stresses produced in the elements by the allowable stress load combinations do not exceed specified allowable stress (also called working stress design). Strength design is a method of proportioning structural elements such that the computed forces produced in the elements by the factored load combinations do not exceed the factored element strength. The term "strength design" is used in the design of concrete and masonry structures. Load and Resistance Factor Design (LRFD) is a method of proportioning structural elements using load and resistance factors such that no applicable limit state is reached when the structure is subjected to all appropriate load combinations. The term "LRFD" is used in the design of steel and wood structures. I w:\2008\0897003_cAy-of-renton_stonegate\09-reports\9.04-drftrpt\june08\preliminary structrual evaluation_rev.doc !: Ksnnedj Jor, �:en itl'�.ants. Im ' Memorandum Ryan Ray, P.E. 13 June 2008 ' 0897003 Page 2 Design Loads F Kennedy/Jenks Consultants 1) Dead Loads: Dead loads should consist of the weight of all materials and fixed equipment incorporated into the building or other structure. 2) Live Loads: Live loads are those loads produced by the use and occupancy of the building or structure and do not include dead load, construction load, or environmental loads such as wind load, snow load, rain load, earthquake load or flood load. Floors should be designed for the unit loads as noted in the table below. Table 1: Minimum Uniformly Distributed Live Loads and Minimum Concentrated Live Loads Occupancy or Use Uniform (psf) Concentrated Ibs Fixed Ladders 300 Handrails, guardrails, and grab bars 50 200 Sidewalks, vehicular driveways 250 8,000 For additional loads not indicated in the table design should be for the unit loads as set forth in ASCE 7-05, Table 4-1. Concrete floor slabs on grade should not be less than those given for heavy manufacturing or storage warehouse; 250 psf uniform load and 3,000 pound concentrated load except in areas where vehicles may access and then the concentrated load should be increased to 8,000 pounds. Floor live loads in equipment rooms, pump rooms, electrical rooms, and areas where equipment may be moved to various locations should be not less than those given for light manufacturing or storage warehouse; 125 pounds per square foot (psf) uniform load and 2,000 pound concentrated load. Live loads for grated and plated areas should equal or exceed the corresponding floor live load for the given area. Access hatches should equal or exceed the corresponding floor live load for the given area. Vehicle loads shall be in accordance with the latest edition of the AASHTO Standard Specifications for Highway Bridges. There are four standard classes of highway loading: H 20, H 15, HS 20, and HS 15. Loadings H 15 and HS 15 are 75 percent of loadings H 20 and HS 20, respectively. The H loadings are for two axle trucks and the HS loadings are for a tractor truck with a semi -trailer. The maximum axle loading for an H 20 or HS 20 vehicle is 32,000 pounds and the maximum axle loading for an H 15 or HS 15 vehicle is 24,000 pounds. 3) Snow Loads: The pump station building should be designed in accordance with ASCE 7-05 Chapter 7 and the coefficients in the table shown below. 1 t\0015\00018.001\tacility eval #28576\predesign reportlkennedyjenWappendix g preliminary structrual evaluation_rev.dce 9 KennaCr an e Cun ul ants. Inc Kennedy/Jenks Consultants IMemorandum Ryan Ray, P.E. ' 13 June 2008 0897003 Page 3 Table 2: Snow Load Design Requirements and Criteria Description of Coefficient Coefficient Occupancy category IV Ground Snow Load, p , lb/ft2 20 Thermal Factor, Ct 1.0 Exposure Factor, Ce 0.9 Snow Importance Factor, 1 1.2 I 4) Wind Loads: The pump station building should be designed in accordance with the Simplified method described in ASCE 7-05 Section 6.4: ' Table 3: Wind Load Design Requirements and Criteria Description of Coefficient Coefficient Exposure flat and generally open terrain C Basic wind speed, mph 85 Wind stagnation pressure PS30 See ASCE 7-05 Figure 6-2 by zone Height and exposure Coefficient A = 1.21 Exposure factor KZt = 1.0 Wind Importance Factor Iw = 1.15 5) Earthquake Loads: Buildings and structures will be designed to resist the effects of earthquake ground motions in accordance with adopted building codes and national standards for non -building structures. The purpose of the earthquake provisions in building codes is primarily to safeguard against major structural failures and loss of life, not to limit damage or maintain function. The design basis ground motion utilized in the design of the buildings and treatment structures is that ground motion that has a 10 percent chance of being exceeded in 50 years. The design of new buildings and the earthquake forces shall be determined considering location, site characteristics, occupancy, configuration, structural system and building height. The existing buildings and new buildings are primarily bearing wall structural systems with masonry shear walls utilized as the lateral force resisting ' system. The pump station building will have a flexible roof diaphragm of structural metal materials. Seismic load design requirements and criteria are summarized in the table below: ' f:\0015\00018.001\facility eval a28576\predesign report\kennedyjenWappendix g preliminary structrual evaluation_rev.doc ': Kenged;••,;nt<: fon;rillanG !rC ' Memorandum Ryan Ray, P.E. 13 June 2008 0897003 Page 4 Fj Kennedy/Jenks Consultants Table 4: Seismic Load Design Requirements and Criteria Description of Coefficient Coefficient Occupancy Category IV Seismic Importance Factor, 1 1.50 Seismic Importance Factor, 1p 1.50 or as noted forequipment Short Period Spectral Response Coefficient SS = 1.399 Long Period Spectral Response Coefficient S, = 0.476 Site Coefficient FA = 1.0 Site Coefficient Fv = 1.5 Short Period Design Coefficient SpS = 0.933 Long Period Design Coefficient SD1 = 0.484 Seismic Design Category D Overstren th and Ductility Coefficient, R 5 for masonry, 6.5 for wood Seismic Amplification Factor, 0 2.5 for masonry, 3 for wood Hydraulic structures are considered special structures by the building codes and require special consideration for their response characteristics and environment that is not covered by most building codes. Earthquake loads for non -building liquid containing concrete structures should be determined utilizing ACI 350.3-06 Standard. It should be noted that the ACI standard provides results at allowable stress levels, which are lower than seismic forces at strength levels, which are obtained from the 2006 IBC. In addition to calculating the seismic loads on rectangular and circular liquid containing concrete structures the ACI 350.3 standard will be utilized for determining the freeboard associated with the maximum wave oscillation generated by earthquake acceleration. 6) Other Minimum Loads: In addition to the loads listed above buildings and non -building structures will be designed to resist other loads including fluid pressures, hydrostatic uplift, lateral soil pressures, ponding loads, and self -straining forces. Structural Tests and Inspections Structural tests and inspections shall be provided for certain types of work. The drawings and the technical specifications will provide detailed information on the quality assurance and testing and inspection requirements for different materials in the shop and in the field. • Special Inspections: Special inspections for certain materials of construction or procedures will be provided as noted on the Special Inspection and Testing Schedule on the Structural Drawings. fA0015100018.001Vacility eval N285761predesign repoftennedyjenkslappendix g preliminary structrual evaluation_rev.doc Y_nnari Jenks on;,d!an,,. jr, Kennedy/Jenks Consultants ' Memorandum Ryan Ray, P.E. 13 June 2008 0897003 Page 5 • Structural Observation: Structural observation by the engineer of record shall be provided for all new construction for buildings and non -building structures in Seismic Design Category D and or when designated by the engineer of record or the local building official. Foundations and Retaining Walls Foundations and retaining walls for buildings should be designed in accordance with the recommendations provided in the geotechnical investigation. Concrete Buildings and Structures Concrete buildings should be designed in accordance with Chapter 19 of the 2006 IBC with the 2007 Washington State Amendments, and with the and Building Code Requirements for Reinforced Concrete (ACI 318-05) published by the American Concrete Institute. Concrete treatment structures should be designed in accordance with the ACI Standard Environmental Engineering Concrete Structures (ACI 350R-06) published by the American Concrete Institute. Different types of concrete should be utilized where different compressive strengths are required or where different performance requirements are required of the mix design. In general, one or more of the following mix designs should be utilized for concrete building construction: ITable 5: Concrete Mix Design Types 1 Concrete Type A B C D E Specified 28-Day Compressive 4,000 4,500 4,000 4,500 2,500 Strength (lb/in2) Maximum Coarse Aggregate Size 1-1/2 1-1/2 1 1 1 (in) Air Content at Point of Placement 5-1/2 5-1/2 1 4-1/2 1 (%) Maximum Water-Cementitious 0.45 0.40 0.50 0.45 0.55 Material Ratio Minimum Cementitious Material 530 590 570 570 510 Content (lb/yd3) Maximum 28-Day Drying 0.05 0.05 -- -- -- Shrinkage (%) I fA0015\00018.001\facility eval N2857ftredesign report\kennedyjenks\appendix 9 preliminary structrual evaluation_rev.doc r):{_np._iAy jomkl� , n;tw? s, :or; Kennedy/Jenks Consultants ' Memorandum Ryan Ray, P.E. 13 June 2008 0897003 Page 6 ' Type A and B concretes are typically - - yp utilized for non building liquid containing structures such ' as the Lift Stationl. Type A concrete is for normal sanitary exposure where crack width is intended to be limited to 0.01 inches. Type B concrete is for severe sanitary exposure where crack width is intended to be limited to 0.0085 inches. Since the Lift Station will come in contact with raw wastewater, we would recommend type B concrete and we would recommend ' evaluating a coating. Type C and D concretes are typically utilized for buildings. Type C concrete is a basic building concrete and will be utilized in the pump station where type B concrete is not required. Type D concrete is concrete for severe weather conditions with ' significant freezing and thawing. Type E concrete will be used when strength and durability are not requirements such as for sidewalks, curbs, bollards and other non-structural concrete. ' Concrete buildings and structures should be designed with bar cover provided over reinforcing steel meeting or exceeding the requirements of ACI 350 for environmental engineering concrete structures. ' Masonry Buildings and Structures One alternative for the Control Building is to use masonry construction. Masonry buildings and ' structures should be designed in accordance with Chapter 21 of the 2006 IBC with the 2007 Washington State Amendments, and the Building Code Requirements for Masonry Structures, ACI 530, published by the American Concrete Institute. Masonry buildings and structures ' should be designed with masonry units with a minimum compressive strength of 1,900 psi, unless higher strengths are required, so that a total masonry assemblage shall have a minimum compressive strength of 1,500 psi at 28 days. Wood Buildings and Structures The other alternative for the Control Building is to use wood construction. Wood buildings and structures should be designed in accordance with Chapter 23 of the 2006 IBC with the 2007 Washington State Amendments, and the 2005 National Design Specification for Wood Construction, published by the American Forest and Paper Association. M0015\00018.001\tacilily eval N28576\predesign report\kennedyjenks\appendix g preliminary structrual evaluation_rev.doc K�nneJ; Inc