5900 36TH AVE W SEPA 015 - 034 - SOUNDVIEW BUSINESS CAMPUS - VERITAS Land Use Decision Documents 2025-04-22

Water Quality Environmental baseline habitat features for water quality include temperature, sediment/turbidity, and chemical contamination/nutrients. Temperature Temperature data was unavailable. However, given the existence of streamside vegetation, large woody debris, adjacent steep slopes, and known use by salmonids, it is assumed that temperatures are normally within properly functioning ranges. Based on these conditions, the action area is properly functioning for this element. As the proposed action will have no effect on water temperature, the baseline condition of this element will be maintained. Sediment/Turbidity High levels of turbidity were recently rectified in 2012 by the diversion of the stream into a historic channel on the opposite side of the railway. Restorative actions have created gentler gradients and a culvert diverter located at the culvert passing under W Mukilteo Boulevard directs excess waters into the previous, non -fish bearing channel during large storm events. These factors maintain conditions of low turbidity and reduced sediment within the water column. Based on these findings, the action area is properly functioning for this element. Although unlikely, construction activities, including clearing and grading, may temporarily degrade the environmental baseline for sediment and turbidity. The project will incorporate erosion control BMPs to minimize sediment entry into downstream Japanese Gulch Creek, and will comply with related project permits and approvals. Sediment is expected to be temporary during construction and this habitat parameter will be maintained over the long term. Chemical Contamination/Nutrients Specific chemical contamination and nutrient data was unavailable for this metric. However, pre-existing garbage dumpsites existed in the creek downstream of the project site prior to stream restoration efforts. It is unclear if the chemical pollution caused by this waste (i.e. old oil barrels) has been remedied by these efforts. Additionally, given the heavy industrial use existing within the basin that is drained by Japanese Gulch creek, chemical contaminants are likely present in the water column. Based on these conditions, chemical contamination and nutrient levels have been determined to be at risk for this element. By designing the stormwater detention and treatment system to meet minimum state requirements, including enhanced treatment, the proposed action will have no measurable effect on chemical contamination/nutrients. As a result, the baseline condition of this element will be maintained. Habitat Habitat access includes any physical in -water barriers that may impede fish migration. Habitat elements include substrate, large woody debris (LWD), pool frequency, pool quality, off -channel habitat, and refugia. Biological Evaluation 8 WRI #14109 Soundview Business Campus Revision #2: October 2, 2015