Loading...
HomeMy WebLinkAboutC_ERC_Deternination_Applicant_Letter_180525.pdf May 25, 2018 David Christensen City of Renton 1055 S Grady Way Renton, WA 98057 SUBJECT: ENVIRONMENTAL THRESHOLD (SEPA) DETERMINATION Kennydale Lakeline Assessment, LUA18-000277, ECF, SME Dear Mr. Christensen: This letter is written on behalf of the Environmental Review Committee (ERC) to advise you that they have completed their review of the subject project and have issued a threshold Determination of Non-Significance. Please refer to the enclosed ERC Report and Decision for more details. Appeals of the environmental determination must be filed in writing on or before 5:00 p.m. on June 8, 2018, together with the required fee with: Hearing Examiner, City of Renton, 1055 South Grady Way, Renton, WA 98057. Appeals to the Examiner are governed by RMC 4-8-110 and more information regarding the appeal process may be obtained from the Renton City Clerk’s Office, (425) 430 -6510. If the Environmental Determination is appealed, a public hearing date will be set and all parties notified. If you have any questions or desire clarification of the above, please call me at (425) 430-7289. For the Environmental Review Committee, Clark H. Close Senior Planner Enclosure cc: Burr, Hudson, Reimers, Dahlby, Stoneman, Richards / Parties of Record DEPARTMENT OF COMMUNITY AND ECONOMIC DEVELOPMENT Project Location Map ERC Report_Kennydale Lakeline AssessmentKennydale Lakeline Assessment ENVIRONMENTAL REVIEW COMMITTEE REPORT ERC MEETING DATE: May 21, 2018 Project Name: Kennydale Lakeline Assessment Project Number: PR18-000184 Land Use Permit Number: LUA18-000277, ECF, SME Project Manager: Clark H. Close, Senior Planner Applicant/Contact: David Christensen, Wastewater Utility Manager / City of Renton / dchristensen@rentonwa.gov / 1055 S Grady Way 5th Fl. Renton, WA 98057 Project Location: Renton Kennydale Area. Along Lake Washington from approximately 2725 Mountain View Ave N (APN 0623059005) to 3905 Lake Washington Blvd N (APN 3342700011). Project Summary: The applicant is requesting a Shoreline Exemption and Environmental (SEPA) Review to evaluate the condition of the Kennydale Lakeline Sewer System. During the 2018 summer fish window, the project proposes to allow the City of Renton Wastewater Utility to complete a physical inspection of the pipe, perform pipe sampling, install manholes, and complete pipe cleaning in and along Lake Washington to determine what is needed to properly maintain the system and evaluate replacement options. The results of the evaluation would determine the remaining useful life of the system and may result in recommendations for future improvements. The pipeline evaluation and associated work would be located in Lake Washington Reach E, in select areas with moderate landslide hazards, and in an area with potential cultural resources. Coordination with property owners is anticipated with the work. Exist. Bldg. Area SF: N/A Proposed New Bldg. Area (footprint): Proposed New Bldg. Area (gross): None None Site Area: N/A Total Building Area to Remain GSF: N/A STAFF RECOMMENDATION: Staff Recommends that the Environmental Review Committee issue a Determination of Non-Significance (DNS). Lake Washington DocuSign Envelope ID: 8B83E200-7C11-4E8B-9FE2-30698BBA26C7 City of Renton Department of Community & Economic Development Environmental Review Committee Report KENNYDALE LAKELINE ASSESSMENT LUA18-000277, ECF, SME Report of May 21, 2018 Page 2 of 7 ERC Report PART ONE: PROJECT DESCRIPTION / BACKGROUND The applicant, City of Renton Wastewater Utility Systems, is requesting a Shoreline Exemption and Environmental (SEPA) Review to assess the condition of the Kennydale Lakeline Sewer System (KLSS). The sewer line is located in the Residential-8 zone in Lake Washington (Exhibit 2). This maintenance project is intended to complete a physical inspection of the sewer pipeline at up to thirteen (13) locations to determine what is needed to properly maintain the system and evaluate replacement options. Condition evaluation would include ultrasonic thickness testing at five (5) locations, pipe sampling via the collection of a single coupon on the mainline, collection of up to three (3) coupons on lateral lines, and temporary access to two (2) existing manholes for lake line cleaning. Two (2) additional locations would be accessed, pipe sections would be removed for evaluation, and the section would be replaced with manh oles below grade. The project locations are aquatic and all work would be staged from a floating barge and/or boat. Divers would be deployed from the barge/boat to expose the sewer lake line and conduct maintenance activities. In general, the work plan would involve the installation of site isolation best management practices (BMPs), followed by placement of a shoring system, if required, and pipeline excavation using a suction dredge. Once the pipeline is exposed the pipeline would be evaluated and sedi ment sampling or corrosion/thickness measurement may occur. Depending on the location, one of three types of actions would occur at this point: either 1) a pipeline sample or coupon would be removed for corrosion and thickness testing and repaired with compression fitting; 2) ultrasonic pipeline thickness testing; or 3) a section of pipeline would be removed for testing, and replaced with a manhole. These coupons, collected from several locations, would provide valuable information on the condition of the lake line pipe. One coupon would be collected near 3703 Lake Washington Blvd N. This coupon is at a relatively high elevation along the lake line that is more likely to have been exposed to corrosive atmosphere. Additional coupons would also be collected on laterals in front of 2905 Mountain View Ave N, 3107 Mountain View Ave N, and 3703 Lake Washington Blvd N. Pipeline sampling at these locations may also impact the adjacent properties at 2909 Mountain View Ave N and 3103 Mountain View Ave N (Exhibits 3 and 4). These laterals are also at relatively high elevations along the lake line and experience intermittent gas exposure . These coupons would supply information about pipe corrosion under adverse conditions. The results of the evaluation would aid in formulating a conservative estimate of the remaining useful life and vulnerability of the system and may result in recommendations for future improvements. Following pipeline repair, the substrate would be returned to pre-construction conditions and BMPs would be removed. No substantial changes would be made to the overall structure or layout of the pipeline and all elements would be below final grade. The KLSS was originally constructed in 1972 to provide sanitary sewer service to approximately 55 to 60 lakefront homes along Lake Washington from the north end of Gene Coulon Memorial Beach Park to just south of May Creek. The pipeline evaluation and associated work would be located in Lake Washington Reach E, in select areas with moderate landslide hazards, and in an area with potential cultural resources. The proposed work follows the Phase 2A of the Lake Line Condition Assessment which included ultrasonic thickness testing and visual inspection of exposed portions of the lake line as well as survey, bulkhead assessment and hydraulic assessment. As part of the hydraulic assessment it was concluded that the hydraulic capacity of the lake line is reduced, indicative of partial blockages in two general areas. These partial blockages are likely the result of solids settlement caused by velocities below those needed for self - cleaning. Current access from the shoreline for cleaning is limited, and settled solids cannot effectively be DocuSign Envelope ID: 8B83E200-7C11-4E8B-9FE2-30698BBA26C7 City of Renton Department of Community & Economic Development Environmental Review Committee Report KENNYDALE LAKELINE ASSESSMENT LUA18-000277, ECF, SME Report of May 21, 2018 Page 3 of 7 ERC Report removed using the shore-based cleaning protocol. Therefore to address these partial blockages, it is proposed that three (3) existing submerged manholes on the lake line be temporarily accessed for cleaning. Temporary access from the lake surface would be obtained with steel riser sections connected to the manhole structure. Once accessed, wastewater from the manholes and adjacent sections of the lake line would be removed prior to cleaning. It is proposed that the cleaning process would use a jetter hose to flush solids toward the manhole where they would be removed by a vacuum. Closed circuit television (CCTV) inspection would be performed before and after cleaning to evaluate the effectiveness of the cleaning procedure. Properties at 2827, 2909, 3111, and 3119 Mountain View Ave N, would experience short-term construction impacts due to their proximately to the manhole location. The two (2) new proposed manholes would be at low points along the undulating sewer to facilitate solids removal. Their locations would facilitate cleaning of a partial blockage believed to be impacting the southern portion of the pipe. The three (3) existing submerged manholes would be used to clean the northern blockage. The proposed manholes would be buried to comply with anticipated permit requirements. Flexible couplings would be installed on the lake line approximately 10 feet from the manhole to enable localized lowering of the sewer profile and ensure that the manhole cover is below the lakebed. This would allow the manholes to be installed without permanently modifying the lakebed, which would trigger a more intensive permitting process and likely preclude this work from being performed in this summer. The proposed work would be conducted between July 16, 2018 and September 30, 2018 (work windows for fish protection for Lake Washington) and would include a condition assessment on parts of the pipe not currently exposed. This assessment would enable additional analyses of the pipe material to determine the amount of corrosion and remaining useful life of the pipe to aid in the City’s strategic planning process. A summary of the work plan includes the following steps: 1. Surround the work area with a floating silt curtain, starting with a collapsed curtain and expanding it so as to eliminate fish from the work area. Once expanded to enclose the work area, the bottom of the silt curtain would be anchored to the lake bed with sandbags at four foot intervals. The curtain would remain in place throughout the work and for a sufficient period after the work to allow the vast majority of sediments to settle. 2. Conduct turbidity monitoring adjacent to the work zone before, during, and after the work. Results would be documented and any noted exceedances would lead to a) adjustment of work practices, or b) stoppage of the work until suitable adjustments can be made. 3. Place a shoring box along the pipeline surrounding the excavation zone. The shoring box would settle down to the base of the excavation as the work progresses. 4. Expose the buried pipeline by suction dredging within the shoring system. Dredging would be conducted using a boat/barge‐mounted trash pump. Excavated materials would be placed outside the shoring but within the silt curtain perimeter. 5. Reduced water usage would be requested of home owners adjacent to the sewer prior t o commencement of work. Flush the pipeline with municipal water to remove most of the sewage prior to cutting the pipe. 6. Cut a 4‐6‐inch diameter hole from the pipe for thickness and corrosion testing. Seal the hole with a pipe repair coupling. DocuSign Envelope ID: 8B83E200-7C11-4E8B-9FE2-30698BBA26C7 City of Renton Department of Community & Economic Development Environmental Review Committee Report KENNYDALE LAKELINE ASSESSMENT LUA18-000277, ECF, SME Report of May 21, 2018 Page 4 of 7 ERC Report 7. Cut through the pipe at the downstream end of the work zone and place a plate to seal the downstream pipe from excessive lake water intrusion. Cut through the pipe at the upstream end of the work zone and removing the existing pipe between the cuts. 8. Replace the removed pipe section with a new pipe segment that includes a manhole to facilitate future cleaning operations. The manholes would be left below the lake bed (Exhibit 5). Install repair couplings to join and seal the replacement segment to the existing pipeline. 9. Return the sewer system to normal operation. Check for leaks and ensure KLSS is functioning properly. 10. Suction dredge excavated materials back into the excavation zone while removing the shoring system. Shovel/rake/hydrojet finished surface to original grade . 11. Wait until sediments have settled from the work area before removing the floating silt curtain. Several permits would be required for either maintenance of the existing line or for conducting a conditions assessment for the existing line, which would include in-water work and disturbance of the lakebed. The following other government approvals/permits would be required: US Army Corp of Engineers (“Corps”) permit to meet requirements of the Rivers and Harbors Act Section 10 and Section 404 of the Clean Water Act, Hydraulic Project Approval (HPA) for projects located near or within a Water of the State, Section 401 Water Quality Certification from Washington State Department of Ecology (“Ecology”) (possibly required), and Hydraulic Project Approval (HPA) from Washington Department of Fish & Wildlife (WDFW). The Joint Aquatic Resource Permit Application (JARPA) process is used to request the HPA, CWA Section 401 Certification, Section 404, and Section 10 permits. Issuance of Section 404 and Section 10 permits by the Corps is contingent on completion of the National Environmental Policy Act (NEPA) and the federal Endangered Species Act (ESA) processes. Additional SEPA review is anticipated for future improvements, maintenance, or replacement of the Kennydale system after the scope and schedule for those improvements are known. PART TWO: ENVIRONMENTAL REVIEW In compliance with RCW 43.21C.240, the following environmental (SEPA) review addresses only those project impacts that are not adequately addressed under existing development standards and environmental regulations. A. Environmental Threshold Recommendation Based on analysis of probable impacts from the proposal, staff recommends that the Responsible Officials: Issue a DNS with a 14-day Appeal Period. B. Exhibits Exhibit 1 ERC Report Exhibit 2 Location Map Exhibit 3 Vicinity Map Exhibit 4 Location Reference Table Exhibit 5 Lake Line Manhole Plans Exhibit 6 Environmental Conditions Report DocuSign Envelope ID: 8B83E200-7C11-4E8B-9FE2-30698BBA26C7 City of Renton Department of Community & Economic Development Environmental Review Committee Report KENNYDALE LAKELINE ASSESSMENT LUA18-000277, ECF, SME Report of May 21, 2018 Page 5 of 7 ERC Report C. Environmental Impacts The proposal was circulated and reviewed by various City Departments and Divisions to determine whether the applicant has adequately identified and addressed environmental impacts anticipated to occur in conjunction with the proposed development. Staff reviewers have identified that the proposal is likely to have the following probable impacts: 1. Earth Impacts: The project site is located in Lake Washington, waterward of the Ordinary High Water Line. The KLSS corridor is approximately 4,800 linear feet (Exhibit 6). The shoreline in the proposed work area runs primarily parallel to the highly modified shoreline, approximately 4,500 linear feet. The shoreline consists of riprap, gabion walls, vertical bulkheads, gravel beaches from south of Coleman Point, at the Lake Washington Flush Station, north to May Creek. Overwater structures include docks associated with single-family residences and a log boom delineating the designated swimming area at Kennydale Beach Park. The adjacent uplands are residential, relatively flat and rolling. Slopes along the shoreline range from flat (less than 15 percent slope) to gently or moderately sloping (less than 40 percent slopes), with a majority of the shoreline having 15 to 25 percent slopes. Slopes in each project location are less than 1 percent, indicating low risks to the existing moderate landslide hazards. The project is not located near steep slopes and would not affect steep slopes. The bathymetry of the lake is gradual in the project vicinity with water depths between 6 and 20 feet. The sediment characteristics underlying the water along the vessel routes in the study area include sand, gravel, and cobble, along with various combinations of these sediment types. Excavation would be limited to the volumes sufficient to expose the sewer pipe. Excavated areas would be no larger than 20 feet wide by 36 feet long by 6 feet deep. Up to approximately 279 cubic yards of material may be excavated. The applicant estimates between 5 and 234 cubic yards of excavation depending upon the activity proposed at each site. Material would be stockpile d inside the floating turbidity curtain. After completing inspection and repair at each location, excavated sediments would be used to return the lakebed to its original grade. According to the applicant, no erosion is expected as a result of this project. Excavation and site restoration would occur over approximately five (5) working days at each location. A sediment curtain would be used to prevent material from being discharged beyond the project site. Excavation would be limited to the smallest amount necessary to expose the pipe and conduct inspections and/or make repairs. Mitigation Measures: No further mitigation recommended. Nexus: N/A 2. Air Impacts: It is anticipated that some temporary air quality impacts associated with the assessment and excavation work of the KLSS would occur. The project would require a work barge/boat which includes water‐jetting or suction dredge to perform underwater excavation. Emissions from project construction would be limited to roughly three (3) gasoline generators during daily operations plus outboard boat engines for site access and environmental monitoring during operations. DocuSign Envelope ID: 8B83E200-7C11-4E8B-9FE2-30698BBA26C7 City of Renton Department of Community & Economic Development Environmental Review Committee Report KENNYDALE LAKELINE ASSESSMENT LUA18-000277, ECF, SME Report of May 21, 2018 Page 6 of 7 ERC Report Upstream sewage would be diverted to Pump Station #14 wet well for storage and the pipeline would be flushed with freshwater prior to commencing with the work. This would ensure that no sewer gases are released into the environment. Should the work take long enough to fill the wet well, Vactor vacuum trucks would be available to empty the wet well and dispose of the sewage in another sewer service area. This would ensure that no waste would enter Lake Washington. Maintenance of the equipment to meet State and Federal air quality requirements would serve to mitigate the potential adverse impacts. No further site specific mitigation for the identified impacts from typical vehicle and construction exhaust is required. Mitigation Measures: No further mitigation recommended. Nexus: N/A 3. Environmental Health a. Environmental Health Hazards Impacts: The project would include removing coupons from the sewer pipeline for testing. Best management practices related to the handling and storage of any environmental health hazards would be implemented during the sewer line inspection to avoid and minimize any potential hazards. The workers’ health would be protected during demolition activities by applicable regulations regarding removal of hazardous materials from Washington State Department of Labor and Industries, the Environmental Protection Agency and the Washington State Department of Ecology. Mitigation Measures: No further mitigation recommended. Nexus: N/A b. Noise Impacts: Temporary, short-term impacts are anticipated from transit to and from the inspection site from outboard engines, the operation of water jet/suction dredge equipment, and generators required to operate the equipment or compressors providing air to underwater workers. Project- related noise is anticipated to attenuate to background levels within 283 feet of the project. No changes to noise levels would occur following the completion of the project. The equipment noise would be regulated through the City’s adopted noise level regulations per Chapter 8 -7, RMC. Permitted work hours in or near residential areas are restricted to the hours between seven o’clock (7:00) a.m. and eight o’clock (8:00) p.m. Monday through Friday. Work on Saturdays is restricted to the hours between nine o’clock (9:00) a.m. and eight o’clock (8:00) p.m. No work is permitted on Sundays. The applicant indicated that all the construction noise impacts are anticipated to occur during daylight hours. No unusual noise impacts are proposed, which would require further levels of mitigation. Mitigation Measures: No further mitigation recommended. Nexus: N/A 4. Aesthetics Impacts: During inspection and repair activities, a barge/boat would be located at the site. These vessels would not be higher than 10 feet above the water level and would be onsite for up to five (5) days at each location. Upon completion, all structures and repair work on the sewer pipeline would be buried below grade in the bed of Lake Washington. DocuSign Envelope ID: 8B83E200-7C11-4E8B-9FE2-30698BBA26C7 City of Renton Department of Community & Economic Development Environmental Review Committee Report KENNYDALE LAKELINE ASSESSMENT LUA18-000277, ECF, SME Report of May 21, 2018 Page 7 of 7 ERC Report Mitigation Measures: No further mitigation recommended. Nexus: N/A 5. Historic and Cultural Preservation Impacts: In the SEPA Checklist (“Checklist”), the applicant indicated that there are no historic structures or sites present in the project area. However, historic and pre-historic settlements are known to have existed around Lake Washington. The proposed excavation, maintenance and repair activity would be limited to the disturbance area of the already buried pipeline within the lake bed. Probes would be used to confirm the pipe’s location prior to excavation. The Checklist concludes that because the pipeline was installed in 1972, all relevant lake sediments have been considered previously disturbed and thus the applicant is not anticipating the discovery of any historic artifacts in the anticipated area of excavation. If any historic or archaeological resources are encountered during implementation of maintenance activities, work would be stopped in accordance with RCW 27.53.060 and 27.44.020 and a professional archaeologist would be called to assess the significance of the find. No comments were received from the Washington State Department of Archeology and Historic Preservation. Mitigation Measures: No further mitigation recommended. Nexus: N/A D. Comments of Reviewing Departments The proposal has been circulated to City Department and Division Reviewers. Where applicable, their comments have been incorporated into the text of this report.  Copies of all Review Comments are contained in the Official File and may be attached to this report. The Environmental Determination decision will become final if the decision is not appealed within the 14-day appeal period (RCW 43.21.C.075(3); WAC 197-11-680). Environmental Determination Appeal Process: Appeals of the environmental determination must be filed in writing together with the required fee to: Hearing Examiner, City of Renton, 1055 South Grady Way, Renton, WA 98057, on or before 5:00 p.m. on June 8, 2018. RMC 4-8-110 governs appeals to the Hearing Examiner and additional information regarding the appeal process may be obtained from the City Clerk’s Office, Renton City Hall – 7th Floor, (425) 430-6510. DocuSign Envelope ID: 8B83E200-7C11-4E8B-9FE2-30698BBA26C7 DEPARTMENT OF COMMUNITY AND ECONOMIC DEVELOPMENT ENVIRONMENTAL (SEPA) DETERMINATION OF NON-SIGNIFICANCE (DNS) PROJECT NUMBER: LUA18-000277, ECF, SME APPLICANT: David Christensen / (425) 430-7212 / 1055 Grady S Way, Renton, WA 98057 PROJECT NAME: Kennydale Lakeline Assessment PROJECT DESCRIPTION: The applicant is requesting a Shoreline Exemption and Environmental (SEPA) Review to evaluate the condition of the Kennydale Lakeline Sewer System (KLSS). During the 2018 summer fish window, the project proposes to allow the City of Renton Wastewater Utility to complete a physical inspection of the pipe, perform pipe sampling, install manholes, and complete pipe cleaning along Lake Washington to determine what is needed to properly maintai n the system and evaluate replacement options. The results of the evaluation would determine the remaining useful life and vulnerability of the system and may result in recommendations for future improvements. The KLSS was originally constructed in 1972 to provide sanitary sewer service to approximately 55 to 60 lakefront homes along Lake Washington from the north end of Gene Coulon Memorial Beach Park to just south of May Creek. The pipeline evaluation and associated work would be located in Lake Washington Reach E, areas of moderate landslide hazards and in an area of potential cultural resources. Coordination with property owners is anticipated as part of the work. The applicant submitted an Environmental Conditions Report with the application. PROJECT LOCATION: Renton Kennydale Area. Along Lake Washington from approximately 2725 Mountain View Ave N (APN 0623059005) to 3905 Lake Washington Blvd N (APN 3342700011). LEAD AGENCY: City of Renton Environmental Review Committee Department of Community & Economic Development The City of Renton Environmental Review Committee has determined that it does not have a probable significant adverse impact on the environment. An Environmental Impact Statement (EIS) is not required under RCW 43.21C.030(2)(c). This Determination of Non-Significance is issued under WAC 197-11-340. Because other agencies of jurisdiction may be involved, the lead agency will not act on this proposal for fourteen (14) days. Appeals of the environmental determination must be filed in writing on or before 5:00 p.m. on June 8, 2018. Appeals must be filed in writing together with the required fee with: Hearing Examiner, City of Renton, 1055 South Grady Way, Renton, WA 98057. Appeals to the Examiner are governed by RMC 4-8-110 and more information may be obtained from the Renton City Clerk’s Office, (425) 430-6510. PUBLICATION DATE: MAY 25, 2018 DATE OF DECISION: JUNE 8, 2018 SIGNATURES: DocuSign Envelope ID: 8B83E200-7C11-4E8B-9FE2-30698BBA26C7 DEPARTMENT OF COMMUNITY AND ECONOMIC DEVELOPMENT Gregg Zimmerman, Administrator Public Works Department Date Rick M. Marshall, Administrator Renton Regional Fire Authority Date Kelly Beymer, Administrator Community Services Department Date C.E. “Chip” Vincent, Administrator Department of Community & Economic Development Date DocuSign Envelope ID: 8B83E200-7C11-4E8B-9FE2-30698BBA26C7 5/17/2018 | 1:32 PM PDT 5/17/2018 | 1:37 PM PDT 5/17/2018 | 2:02 PM PDT 5/17/2018 | 1:13 PM PDT Source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS,AeroGRID, IGN, and the GIS User Community FIGURE 1LOCATION MAP REFERENCE N UMBER:APPLICANT NAME: City of Renton, WAPROPOSED PRO JECT: Install manh oles, collect pipe coupon s, a nd p erform ultrasonic thickness testing on sewer lake line.LOCATION: Lake Wash ington b etwee n2727 Moun tain Vie w Ave N and 3903 LakeWashington Blvd N, Renton, WA 98056SHEET 1 OF 7DATE: 1 -3 1-2018 LAKE WASHINGTON CITY OF RENTON CITY OF MERCER ISLAND ± PROJECT LOCATION 0 1,600 3,200800Feet EXHIBIT 2 RECEIVED 04/20/2018 cclose PLANNING DIVISION DocuSign Envelope ID: 8B83E200-7C11-4E8B-9FE2-30698BBA26C7 Ú 1+002+003+004+005+006+007+008+009+0010+0011+001 2 +0 0 13+00 14+00 15+00 16+00 17+00 18+00 19+00 20+00 21+00 22+00 23+00 24+00 25+00 26+00 27+00 28+00 29+00%,%,")")Lake WashingtonFlush Station ColemanPoint 30032931Site 3 Manhole Site 2 Manhole 222811 2807 28052801 3013 3233 3111 3015 3107 3205 2909 2827 3209 3011 3213 2731 3103 3115 2727 3217 2815 3119 3101 2905 3307 30093007 3001 3005 N 30t h StBurnett A v e N N 31s t StN 29t h St N 32nd St N 33 r d St L a k e W a s h in g to n B lv d N M ountain View A ve N 0 200 400100Feet FIGURE 2VICINITY MAP ± Legend ")Ultrasonic Thickness Testing %,Lateral Coupon New Manhole REFERENCE N UMBER:APPLICANT NAME: City of Renton, WAPROPOSED PRO JECT: Install manh oles, collect pipe coupon s, a nd p erform ultrasonic thickness testing on sewer lake line.LOCATION: Lake Wash ington b etwee n2727 Moun tain Vie w Ave N and 3903 LakeWashington Blvd N, Renton, WA 98056SHEET 2 OF 7DATE: 1 -3 1-2018 Lake Washington OHWM EXHIBIT 3 Ultrasonic Thickness Testing Area of Impact:900 SF Volume of Excavation:5 CY Volume of Fill:5 CY Ultrasonic Thickness Testing Area of Impact:900 SF Volume of Excavation:5 CY Volume of Fill:5 CY Pipe Coupon Area of Impact:900 SF Volume of Excavation:5 CY Volume of Fill:5 CY Pipe Coupon Area of Impact:900 SF Volume of Excavation:5 CY Volume of Fill:5 CY New Manhole (See Figure 5) Area of Impact:3,600 SF Volume of Excavation:117 CY Volume of Fill:113 CY New Manhole (See Figure 5) Area of Impact:3,600 SF Volume of Excavation:117 CY Volume of Fill:113 CY DocuSign Envelope ID: 8B83E200-7C11-4E8B-9FE2-30698BBA26C7 Ú%,")")")Kennydale Beach Park Lake Washington #2Lift Station CO585 2Site 1 Manhole 3909 37193613 36193611 3703 3717360537153711 3821 3625 3825 3837 3805 3901 3979 3601 37073607 37133709 3815 3811340535013307 3905 3827 3401 3411 3903Lake Washington Blvd N 0 200 400100Feet FIGURE 3VICINITY MAP Legend MainlineCoupon ")Ultrasonic Thickness Testing %,Lateral Coupon ± REFERENCE N UMBER:APPLICANT NAME: City of Renton, WAPROPOSED PRO JECT: Install manh oles, collect pipe coupon s, a nd p erform ultrasonic thickness testing on sewer lake line.LOCATION: Lake Wash ington b etwee n2727 Moun tain Vie w Ave N and 3903 LakeWashington Blvd N, Renton, WA 98056SHEET 3 OF 7DATE: 1 -3 1-2018 Lake Washington OHWM Pipe Coupon Area of Impact:900 SF Volume of Excavation:5 CY Volume of Fill:5 CY Pipe Coupon Area of Impact:900 SF Volume of Excavation:5 CY Volume of Fill:5 CY Ultrasonic Thickness Testing Area of Impact:900 SF Volume of Excavation:5 CY Volume of Fill:5 CY Ultrasonic Thickness Testing Area of Impact:900 SF Volume of Excavation:5 CY Volume of Fill:5 CY Ultrasonic Thickness Testing Area of Impact:900 SF Volume of Excavation:5 CY Volume of Fill:5 CY DocuSign Envelope ID: 8B83E200-7C11-4E8B-9FE2-30698BBA26C7 Work Performed Approximate Latitude/Longitude Parcels Impacted Addresses Manhole Installation 47.517663,-122.210646 3342103985 2905 Mountain View Ave N 3342103953 2909 Mountain View Ave N 3342104009 2827 Mountain View Ave N 47.519782,-122.210761 3342103860 3111 Mountain View Ave N 3342103855 3115 Mountain View Ave N 3342103845 3119 Mountain View Ave N Main Line Coupon 47.524637,-122.207548 3342700270 3703 Lake Washington Blvd N Lateral Coupon 47.517816,-122.210748 3342103985 2905 Mountain View Ave N 3342103953 2909 Mountain View Ave N 47.519402,-122.210915 3342103890 3103 Mountain View Ave N 3342103880 3107 Mountain View Ave N 47.524635,-122.207415 3342700270 3703 Lake Washington Blvd N Ultrasonic Thickness Testing 47.519149,-122.211466 3342103895 3101 Mountain View Ave N 47.520493,-122.210316 3342103805 3213 Mountain View Ave N 47.521603,-122.208914 3124059077 3307 Lake Washington Blvd N 47.522364,-122.208507 3124059076 3401 Lake Washington Blvd N 47.523563,-122.207942 3342103580 3501 Lake Washington Blvd N REFERENCE NUMBER: APPLICANT NAME: City of Renton, WA PROPOSED PROJECT: Install manholes, collect pipe coupons, and perform ultrasonic thickness testing on sewer lake line. LOCATION: Lake Washington between 2727 Mountain View Ave N and 3903 Lake Washington Blvd N, Renton, WA 98056 SHEET 4 OF 7 DATE: 1-31-2018 Figure 4 Location Reference Table EXHIBIT 4 DocuSign Envelope ID: 8B83E200-7C11-4E8B-9FE2-30698BBA26C7 SILT CURTAIN (EXTENT OF SILT CURTAIN NOT SHOWN TO SCALE) 8" DI SANITARY SEWER (TYP) 24" DIA. MANHOLE LID 48" DIA. RISER LIMITS OF EXCAVATION 48" DIA. MANHOLE 10' A A LAY BOTTOM OF SILT CURTAIN FLAT AND SECURE WITH SANDBAGS SPACED MAXIMUM 4 FT ON CENTER (TYP ENTIRE PERIMETER) B 36' PIPE REPAIR CLAMP (TYP) FLEXIBLE COUPLING (TYP) B 19'-6"1/31/2018 5:10:43 PM - P:\01621\135-01621-16001\CAD\SHEETFILES\MANHOLE FIGURES\FIGURE 5 - LAKE LINE MANHOLE PLAN.DWG - COLBY, ANDYwww.tetratech.com Copyright: Tetra TechFIGURE 5 CITY OF RENTON LAKE LINE MANHOLE PLAN 1420 FIFTH AVENUE, SUITE 600 SEATTLE, WA 98101 206.883.9300 REFERENCE NUMBER: APPLICANT NAME: City of Renton PROPOSED PROJECT: Install manholes, collect pipe coupons, and perform ultrasonic thickness testing on sewer lake line. LOCATION: Lake Washington between 2727 Mountain View Ave N and 3903 Lake Washington Blvd N, Renton, WA 98056 SHEET 5 OF 7 DATE: 1-31-2018 N10'5'20'0 EXHIBIT 5 DocuSign Envelope ID: 8B83E200-7C11-4E8B-9FE2-30698BBA26C7 48" 24" 48" 12" SILT CURTAIN (EXTENT OF SILT CURTAIN NOT SHOWN TO SCALE)5'-9"LIMITS OF EXCAVATION TEMPORARY RISER ORIGINAL GRADE BACKFILLED WITH NATIVE SEDIMENT AND 6" SPAWNING GRAVEL 12" 1:1 SLOPE 8" DI SANITARY SEWER LAY SILT CURTAIN FLAT TO BOTTOM, SECURE WITH SAND BAGS 19'-6"1/31/2018 5:20:23 PM - P:\01621\135-01621-16001\CAD\SHEETFILES\MANHOLE FIGURES\FIGURE 6 - LAKE LINE MANHOLE SECTION AA.DWG - COLBY, ANDYwww.tetratech.com Copyright: Tetra TechFIGURE 6 CITY OF RENTON LAKE LINE MANHOLE SECTION A-A 1420 FIFTH AVENUE, SUITE 600 SEATTLE, WA 98101 206.883.9300 REFERENCE NUMBER: APPLICANT NAME: City of Renton PROPOSED PROJECT: Install manholes, collect pipe coupons, and perform ultrasonic thickness testing on sewer lake line. LOCATION: Lake Washington between 2727 Mountain View Ave N and 3903 Lake Washington Blvd N, Renton, WA 98056 SHEET 6 OF 7 DATE: 1-17-2018 4'2'8'0 DocuSign Envelope ID: 8B83E200-7C11-4E8B-9FE2-30698BBA26C7 48" 24" 48" 12" LAY SILT CURTAIN FLAT TO BOTTOM, SECURE WITH SAND BAGS 8" DI SANITARY SEWER 5'-9"LIMITS OF EXCAVATION 54"39"TEMPORARY RISER FLEXIBLE COUPLING (TYP) 10' PIPE REPAIR COUPLING (TYP) ORIGINAL GRADE BACKFILLED WITH NATIVE SEDIMENT AND 6" SPAWNING GRAVEL SILT CURTAIN (EXTENT OF SILT CURTAIN NOT SHOWN TO SCALE) 36' 1:1 SLOPE~4'1/31/2018 5:21:53 PM - P:\01621\135-01621-16001\CAD\SHEETFILES\MANHOLE FIGURES\FIGURE 7 - LAKE LINE MANHOLE SECTION BB.DWG - COLBY, ANDYwww.tetratech.com Copyright: Tetra TechFIGURE 7 CITY OF RENTON LAKE LINE MANHOLE SECTION B-B 1420 FIFTH AVENUE, SUITE 600 SEATTLE, WA 98101 206.883.9300 0 4'8'16' REFERENCE NUMBER: APPLICANT NAME: City of Renton PROPOSED PROJECT: Install manholes, collect pipe coupons, and perform ultrasonic thickness testing on sewer lake line. LOCATION: Lake Washington between 2727 Mountain View Ave N and 3903 Lake Washington Blvd N, Renton, WA 98056 SHEET 7 OF 7 DATE: 1-31-2018 NDocuSign Envelope ID: 8B83E200-7C11-4E8B-9FE2-30698BBA26C7 146 N Canal St, Suite 111 • Seattle, WA 98103 • www.confenv .com Kennydale Lakeline Sewer System ENVIRONMENTAL CONDITIONS REPORT Prepared for: City of Renton April 6, 2017 EXHIBIT 6 RECEIVED 04/20/2018 cclose PLANNING DIVISION DocuSign Envelope ID: 8B83E200-7C11-4E8B-9FE2-30698BBA26C7