2018052.pdf

This is a Scopes of Work document for the CSO Basin 34 (I-90) Stormwater Mitigation/Separation Facility project issued by the City of Seattle, Washington. The project encompasses the construction of a diversion structure, stormwater lift station, four modular wetland stormwater treatment systems, four Type 2 deep drywells, five catch basins, approximately 200 linear feet of stormwater forcemain pipe with associated appurtenances including a valve vault, 380 linear feet of stormwater pipe of varying sizes, 250 square yards of HMA pavement, 123 linear feet of sidewalk and driveways, and sundry utility adjustments. The scope of work outlines the technical requirements, design standards, and construction specifications necessary for the completion of this stormwater management facility designed to address combined sewer overflow (CSO) issues in the Basin 34 drainage area along the I-90 corridor.

The document establishes the engineering and construction standards that contractors must adhere to throughout project execution, including specifications for materials, installation procedures, quality assurance, and testing requirements. The project is funded through the City's stormwater and wastewater infrastructure program, with construction anticipated to address environmental compliance and flood mitigation objectives. The scope includes coordination with existing utility systems and adherence to applicable city, state, and federal regulations governing stormwater management and environmental protection.