BHC Consultants LLC 2/27/2025 - Laserfiche WebLink

City of Everett Lift Station No. 1 Valve Replacement Scope of Services 2 EXHIBIT A SCOPE OF SERVICES Background The City of Everett, Washington (City) has selected BHC Consultants, LLC (BHC) to provide engineering and bid assistance services for the Lift Station No. 1 (LS-1) Valve Replacement Project. LS-1 is located at the end of Pigeon Creek Road near where Pigeon Creek enters Possession Sound. Burlington Northern Sante Fe (BNSF) railroad tracks run along the shoreline between LS-1 and Possession Sound. LS-1 was constructed in 1984 to replace an old smaller lift station. A diversion structure was built that receives most of the flow that had been conveyed by the older smaller lift station and routes it through a 24-inch pipeline connecting to the 30-inch influent pipeline that conveys flow to LS-1. The old smaller lift station still receives some flow, but a much smaller amount. A 30-inch gate valve is installed along the 30-inch influent pipeline just downstream of where the 24-inch pipeline connects. This valve could be used to isolate the downstream 30-inch pipeline so that the wet well could be pumped down and accessed for maintenance. When the 30-inch gate valve is closed, flow through the 24-inch pipeline and diversion structure is reversed and instead of flow being conveyed from the old smaller lift station, flow is conveyed to the old smaller lift station. The capacity of the old smaller lift station is such that it can handle the dry weather flows (1 to 2 MGD) that are typically received by LS-1 during dry weather, thereby allowing for maintenance activities in the LS-1 wet well during that time period. The 30-inch gate valve has since become non-functional and the City removed all internal components of the valve, such that only the valve body remains acting like a section of pipe. The City desires to install a new plug valve along the 30-inch influent pipeline. The existing valve is located very near the south bank of Pigeon Creek, making replacement in the same location difficult without impacting the creek. Therefore, the new 30-inch plug valve will be installed on the other side of the creek closer to the LS-1 wet well where there is more space for installation and construction activities. The valve will be installed in a vault to provide access for maintenance. Installation of the valve will require temporarily diverting flow to the old smaller lift station. Although there are various methods that could be employed to divert the flow (plugging lines, line stopping, etc.) constructability and space constraints will need to be considered to determine which methods may be viable for a bidder to use on this project. Given the proximity to the creek, shoreline, and railroad tracks, it is expected that a critical areas report, shoreline permit, and BNSF Utility License Agreement will be required. Additionally, completion of the SEPA process may also be required depending on whether the City determines this work to be exempt or not. Based on the information provided by the City and our understanding of the project as noted above, the primary project elements include: • Constructing a temporary diversion of flow to the old smaller lift station. • Installing a new 30-inch plug valve and vault along the LS-1 influent pipeline. • Assisting with obtaining the necessary permits to conduct the work. This work will be bid with the replacement of a 48-inch valve used to isolate the chlorine contact tank for maintenance at the Everett Water Pollution Control Facility (WPCF) as a single project. Design for replacement of the isolation valve for the chlorine contact tank is provided under a separate scope of services, but since these two replacements will be combined into a single project the budget for common elements are split evenly between the two scopes of services.