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

Floodplain Connectivity Floodplain connectivity within Japanese Gulch Creek appears to have been at least partially reestablished north of W. Mukilteo Boulevard during recent restorative measures. The channelized nature of the stream south of the restoration actions limits this connectivity. Given the combination of reaches with floodplain connectivity and those without, the status of this parameter is considered at risk. This project will not change the existing flood lain connective and as a result will maintain P J g g P connectivity > the baseline condition for this parameter. Change in Peak/Base Flows ' Recent restorative actions have reconnected Japanese Gulch Creek with an existing wetland near the mouth of the stream. Additionally, Japanese Gulch Creek drains approximately a one square - mile basin. These factors are believed to maintain base flows during the summer months. However, the channelized nature of the steam south of W. Mukilteo Boulevard increases the potential for flood events to create large rises in peak flow. For these reasons, this metric is considered at risk in the Japanese Gulch Creek action area. ' This project will not change peak or base flows and, as a result, will maintain the baseline condition for this parameter. Drainage Network The action area and the Japanese Gulch Creek basin in general have experienced an increase in 1 the drainage network due to roads as well as residential, commercial, and industrial development. Based on this, the baseline indicator is at risk in the watershed. The drainage network will be expanded as part of this project, but on a relatively small scale compared to the basin. As a result, this project well maintain the baseline condition for this parameter. Road Density & Location There are several road crossings and generally very dense development over the Japanese Gulch Creek basin and near the gulch bottom. Therefore, the baseline conditions are not properly functioning for the action area and the watershed. This project will not change road density or location and, as a result, will maintain the baseline condition for this parameter. Disturbance History The Japanese Gulch Creek basin has experienced extensive historical disturbance from road construction and residential, commercial, and industrial development. Vast areas of former wetlands have likely been converted to residential and commercial development. Japanese Gulch has a particularly high level of historical disturbance related to the railroad and timber industries during the early 201h century. Baseline conditions for this element are not properly functioning for both the action area and the watershed. Biological Evaluation 11 WRI #14109 Soundview Business Campus Revision #2: October 2, 2015