With over 3 million square-feet of new construction and 37 floors, 2021 7th Ave is the single largest proposed development project in the history of downtown Seattle. The project will cover three city blocks and will take almost eight years to complete. Online retail giant, Amazon.com, will occupy the campus when finished. The complex will include one large tower and multiple smaller buildings, all connected by skybridges. The project was designed by leading Seattle design firm, NBBJ. WaterTectonics worked with Sellen Construction on the Block 14 and Block 19 phases to help permit, design, and deploy an EcoStorm Plus system to reduce suspended solids and a PhatBox to control pH before discharging construction and dewatering water to the sanitary sewer.