400 RIVERSIDE RD SEPA 016 - 039 - RIVERSIDE BUSINESS PARK Land Use Decision Documents 2025-04-14

WRIA 07 Snohomish 9e. Will the in-water construction work comply with the State of Washington water quality standards for turbidity? [help] • Go to http://www.ecy.wa.gov/programs/wq/swgs/criteria.html for the standards. ❑ Yes ❑ No ® Not applicable 9f. If the project is within the jurisdiction of the Shoreline Management Act, what is the local shoreline environment designation? [held • If you don't know, contact the local planning department. • For more information,go to:http://www.ecy.wa.qov/programs/sea/sma/laws rules/173-26/211 designations.html. ❑ Rural ® Urban ❑ Natural ❑ Aquatic ❑ Conservancy ❑ Other Residential 9g. What is the Washington Department of Natural Resources Water Type? [herd • Go to http://www.dnr.wa.gov/forest-practices-water-typinq for the Forest Practices Water Typing System. ® Shoreline ❑ Fish ❑ Non-Fish Perennial ❑ Non-Fish Seasonal 9h. Will this project be designed to meet the Washington Department of Ecology's most current stormwater manual? [help] • If No, provide the name of the manual your project is designed to meet. ® Yes ❑ No Name of manual: 2012 Stormwater Manual for Western Washington, Washington State Department of Ecology 9i. Does the project site have known contaminated sediment? [hejp] • If Yes, please describe below. ® Yes ❑ No Between 2000 and 2001 site grades were raised up several feet to bring site grades above the 100-year floodplain as defined at that time. Dredged material from the Snohomish River was used to raise the grade of the site. In the past couple of years, site grades were raised up to about an additional 61/4 feet to bring the site above the newly defined 100-year floodplain. For the purpose of this report, the surface that existed prior to these two rounds of site filling is referred to as the "former Weyerhaeuser working surface." Currently the shoreline is armored with treated wood bulkhead or old building foundations, riprap, dolphins and treated pilings.The long history of lumber processing operations at the site has led to contamination of the soil and groundwater beneath the site, and the site was later ranked and listed as a cleanup site under the Washington Model Toxics Control Act (MTCA). Weyerhaeuser and the Washington State Department of Ecology (Ecology) entered into a Consent Decree regarding certain cleanup actions for the site and this cleanup has been implemented with oversight by Ecology. The cleanup was designed with the planned redevelopment of the property into a business park or industrial development in mind. However, the cleanup activities only addressed specific locations related to the more significant contamination issues. Consequently, soil and groundwater at lower contamination levels remain across the site, even though some cleanup actions have been undertaken. For this reason, the property is restricted to industrial use. The contaminants of concern on the site related to past Weyerhaeuser activities are total petroleum hydrocarbons (TPHs), carcinogenic polycyclic aromatic hydrocarbons (cPAHs), polychlorinated biphenyls (PCBs), and pentachiorophenol (PCP). The project site has also been impacted by offsite sources of contamination related to the nearby former ASARCO smelter site. These impacts include elevated concentrations of arsenic in the soil and groundwater beneath the site, some of which are above industrial site cleanup action levels. Refer to Revised Draft Report, Predesign Geotechnical Services, Riverside Business Park-Lots 2 through 6, Everett, WA April 10, 2015 Landau Associates JARPA Revision 2015.1 Page 13 of 18