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HomeMy WebLinkAboutCM_constr_mitigation_descrip_20180515_v1.pdfMemo To: Jill Ding, Senior Planner From: Kristi Rettmann City of Renton, Community and Economic Development 1055 S Grady Way, 6th Floor Renton, WA 98057 Stantec 11130 NE 33rd Place Suite 200 Bellevue WA 98004 File: 2002003611 Date: May 15, 2018 Reference: Construction Mitigation Description - #9 on the Submittal Requirements for Environmental Review (SEPA) for the Thunder Hills Sanitary Sewer Replacement Project • Proposed Construction Dates: Provided that all required permitting is in place, construction is anticipated to take place between June 2019 and September 2019. • Hours and Days of Operation: Monday through Friday during normal business hours (8am to 5pm). • Proposed hauling/transportation routes: Any hauling and transportation routes required for this project will be provided by construction company that is selected for the project. • Measures to be implemented to minimize dust, traffic and transportation impacts, erosion, mud, noise, and other noxious characteristics: o To minimize the erosion and sediment runoff impacts from excavation, grading, and trenching activities required of the project, the work will be performed during the dry season (June through September). o Excessive dust will be reduced by spraying water over the disturbed soil area as needed throughout the duration of the excavation and maintenance access road improvement process. o A rock spall pad will be constructed at the point(s) of ingress and egress for construction equipment to help prevent the spread of dust to the adjacent roadways (gated site entrance at Grant Ave S and S 18th Street and at the cleared PSE easement access along S 18th Street). o Trucks transporting excavated or fill material will be covered or have adequate freeboard to prevent dust and particulates from being blown out of the truck. o Any runoff generated by dewatering discharge will be treated through construction of a sediment trap if there is sufficient space. If space is limited, other filtration methods will need to be incorporated. Additional perimeter erosion and sediment control features such as double-silt fencing will be added to reduce the possibility of sediment entering the surface water. o trench and excavation widths and depths will be kept to a minimum during construction. Immediate backfill of trenches, along with timely restoration, will further reduce erosion potential. o Any trucks or construction equipment will be on site for only as long as they are needed and removed from the area and vicinity of Thunder Hills Creek and wetlands as soon as possible. • Any special hours proposed for construction or hauling (i.e., weekends, late nights): No construction is anticipated to take place on late nights, weekends or holidays. • Preliminary traffic control plan: Any preliminary traffic control plan that is required for this project will be provided by construction company that is selected for the project. It is anticipated that this project will require minimal traffic control because the required construction for this project is down in a ravine, absent of traffic or streets. Best Regards, Kristi Rettmann May 15, 2018 Jill Ding, Senior Planner Page 2 of 2 Reference: Construction Mitigation Description - #9 on the Submittal Requirements for Environmental Review (SEPA) for the Thunder rk v:\2002\active\2002003611\permit\sepa\draft submittal\supporting docs\cm_constr_mitigation_descrip_20180515_v1.docx Environmental Scientist Phone: (425) 289-7338 kristi.rettmann@stantec.com Attachment: None c. C.C. V:\2002\active\2002003611\permit\sepa\draft submittal\sepa_files_w_elec_file_standards