Bothell Crossroads Multi-Way Boulevard

Bothell, Washington

HWA was retained by Perteet Engineering on behalf of the City of Bothell to provide environmental consulting and geotechnical engineering services for the Bothell Crossroads project.

The project involves realignment of a major intersection of two state highways, and includes the acquisition of multiple properties by the City for roadway construction and planned future redevelopment. The project alignment crosses or adjoins multiple confirmed or suspected contaminated properties, including over ten former or present gas stations and four dry cleaners. HWA performed Phase I Environmental Site Assessments (ESAs) on over ten properties and Phase II Environmental Site Assessments on seven properties to date, many on expedited schedules. HWA employed an integrated, area-wide approach to better understand multiple plumes and source areas as they related to overall project objectives and property acquisition issues. HWA assisted with property acquisition negotiations, provided remediation cost estimates, regulatory compliance and negotiation for three Agreed Orders, and has helped the City obtain Ecology Remedial Action grants, USEPA Brownfield Cleanup Grants, and CTED Revolving Loan Fund direct grants totaling over $500,000. HWA also prepared SEPA/NEPA discipline reports for soils, ground water, and hazardous materials.

In addition, HWA was retained to provide geotechnical engineering services on the Crossroads project. The project will reconstruct an existing portion of SR 522 and SR 527 to accommodate a pedestrian-friendly space in downtown Bothell as well as provide adequate lanes for arterial traffic. Four through lanes and a center turn lane or median will be provided for vehicular traffic. These lanes will be bordered by landscaped medians and one-way lanes providing parking and wide sidewalks. The project will also extend SR 527 about 300 feet south to create a new 'Tee' intersection with SR 522. The limits of the project area extend from the proposed intersection with SR 522, north to the existing intersection with Reder Way. The Multi-Way Boulevard project (SR 527) will include construction of thin fill embankments, new sidewalks, medians, parking spaces, pavement reconstruction, and traffic signal poles. The scope of our geotechnical engineering input for the SR 522 Bothell Crossroads project includes a review of available geotechnical information; field reconnaissance, conducting a comprehensive site exploration plan, and providing detailed geotechnical recommendations for the proposed improvements. Recommendations will be provided for the: new bridge over Horse Creek; walls along the roadway realignment; foundation requirements for traffic signal poles; new roadway pavements design requirements; site drainage and storm water management; general embankment construction and fill requirements; utility trench backfill requirements; and possible use of recycled materials.