Hart Crowser provided geotechnical design and hydrogeological analysis to support office and retail development on four city blocks in the South Lake Union area. This 1.8-million-square-foot campus has five levels of underground parking that extend below the water level of nearby Lake Union. The 11 buildings are 4 to 12 stories high. The buildings are near the historical Denny Regrade, where fill thickness ranges from 10 to over 25 feet. Our geotechnical analysis addressed potential off-site impacts of settlement of wood waste fill that dewatering this old channel might cause. The project included installing wells, conducting slug tests, and analyzing hydrogeological conditions to evaluate the nature and extent of these potential groundwater impacts, as well as the effects on adjacent water pipes.