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

Sediment/Turbidity Sediment from landwasting slides, erosion, and that which accumulates on impervious surfaces within developed portions of the Edgewater Creek basin has created problematic conditions. Sediment storm runoff is particularly abundant in the lower reaches of Edgewater Creek, creating highly embedded gravel. High levels of turbidity exacerbate this situation. The mean base flow turbidity was measured at 7 NTU (City of Everett, 2014). Based on these findings, the action area is not properly functioning for this element. 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 systems, 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 Water chemistry, metals, and nutrient measurements in Edgewater Creek are within acceptable levels. However, macro -invertebrate data indicates poor to very poor conditions. Macro - invertebrates are used as bio-indicators of ecosystem health. Additionally, coliform bacteria levels were above that allowed by water quality criteria, and are believed to be sourced from pet waste and other anthropogenic influences. Based on these findings, chemical contamination and nutrient levels have been determined to be at risk for this element. By designing the stormwater system to meet minimum state requirements, including enhanced treatment, the proposed action will have no 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. Physical Barriers The culvert running under the BNSF railway is capped by a trash rack and appears to be under water during high tide. Throughout the lower reaches of Edgewater Creek, north of W. Mukilteo Boulevard, there are no apparent physical barriers to fish passage. Therefore, the action area of Edgewater creek is considered properly functioning for this element. No in -stream or near -stream work is proposed, so the proposed action will maintain the baseline condition of this element. Substrate Macro -invertebrate data indicates that there is a low proportion of clean stony substrate in the lower reaches of Edgewater creek. This is likely due to the abundant levels of sediment present within the stream channel. The high level of fines present have embedded the gravely substrate, reducing the habitat functionality for fish spawning. Based on these conditions, the Edgewater Creek action area is considered to be properly functioning for this element. Biological Evaluation 14 WRI #14109 Soundview Business Campus Revision #2: October 2, 2015