2600 FEDERAL AVE 2021 PORT OF EVERETT 2025-09-29

1q:1 Consulting Engineers Page 8 of 13 Minimum Requirement#6: Runoff Treatment: Stormwater treatment systems will be installed for Basins A and M and Federal Avenue Basin 1a as part of this project. Stormwater treatment for Federal Avenue Basin 2 will be provided by either a planned City of Everett regional modular wetland facility or a back-up plan that will include a 'Basic' treatment facility that would be constructed by the Port as part of this project. Which option is dependent on timing of the two projects. The City project will provide treatment if it is constructed by October, 2022. If the City project is abandoned,the Port's back-up treatment facility will be constructed at the end of 2022 or early 2023. The Port's 'Basic' treatment facility is proposed to consist of a wet vault or Contech Stormfilter that is designed for treatment of at least 8,500 square feet of pollution generating impervious surface within Federal Avenue. Design calculations for the Port's back-up treatment facility are not included in this report. The calculations and revised permit plans will be submitted to the City within 30 days following issue of the permit for the Federal Avenue work as agreed to by the City. Ideally, the back-up design is not constructed because it will either be replaced in the future by the regional facility or will be a redundant system that will provide little to no additional treatment benefit and will require unnecessary maintenance. A Contech Stormfilter will be installed at Basin A and will collect stormwater from the regraded portion of Basin A and also Federal Avenue Basin 1a, see Appendix C for treatment system cut sheets. The Contech Stormfilter has an integrated high flow bypass which will allow high-flows that exceed the water quality flow rate to bypass treatment and discharge to Port Gardner Bay via Outfall A. The existing warehouse roof downspouts will be maintained and bypass treatment, discharging to Port Gardner Bay via Outfall A. A CESF treatment system will be installed at Basin M and has been sized for the fully developed basin area (39.40 acres).The CESF treatment system is GULD approved per the Department of Ecology TAPE program and is capable of providing water quality treatment to meet the discharge threshold requirements of Ecology's NPDES Industrial Stormwater General Permit and Basic Treatment requirements.This system is the equivalent to those systems approved for enhanced treatment and will target zinc and copper as well as total suspended solids and turbidity, see section 5.7 below for additional information. A high-flow bypass structure with an integrated lift station will pump the water quality flow rate to the CESF system. Treated stormwater will be discharged back to the main 36 inch storm line and discharge to Port Gardner Bay via Outfall M. The high-flow bypass structure will bypass higher flows exceeding the water quality flow rate. Oil control is not required for this facility. The Norton Terminal's planned use is to provide long term storage of cargo and large equipment. The project Trip Generation Memorandum (see Appendix G) estimates the facility will generate an estimated 14 ADT (7 longshoreman, 2 trips per day) and 15 ADT from trucks.Trucks will be transporting cargo/heavy equipment from the Port of Everett's South Terminal to the Norton Terminal for long term storage. The estimated total ADT of 29 for this facility and the estimated quantity of cargo and heavy equipment is less than the requirements listed in the City of Everett Stormwater Manual, summarized below: