Utilities

Gray Army Airfield Expansion and Infiltration Facilities

Bristol Environmental & Engineering
Joint Base Lewis-McChord, Washington

This seven-acre helicopter apron expansion project allows the US Army to park more helicopters on the airfield. Fast-track construction was done without interrupting air traffic on the adjacent runway. Infiltration facilities were designed to incorporate an innovative infiltration treatment layer which allowed a 50 percent reduction in the infiltration basin size, saving between $250,000 and $500,000, and reducing a six-month construction schedule by two months.

 


Tacoma Central Treatment Plant Upgrade and Expansion

City of Tacoma
Tacoma, Washington

Our work supported the City’s goal to provide increased hydraulic and treatment capacity. Hart Crowser provided environmental, geotechnical, and hydrogeologic services.




 

Harbor Island Pipeline Relocation

Northwest Engineering
Seattle, Washington

Hart Crowser provided geotechnical engineering services for a relocation of petroleum pipelines on Harbor Island. The length of the run was about 3,800 feet. The pipeline alignment crossed beneath several utility lines and railroad tracks. Special attention was given to the impact of the design earthquake on the pipeline, such as liquefaction-induced settlement and lateral spreading.

 


Stormwater Capital Improvement Program

RW Beck
Seattle-Tacoma Airport, Washington

Hart Crowser supported the Port of Seattle's Comprehensive Stormwater Management Plan for the Seattle-Tacoma International Airport. The work included thirteen task orders that involved design and construction of several stormwater ponds, geotechnical design for buried retention and treatment vaults, microtunnel design, directional drilling evaluation, and AKART analysis. One of the impoundment projects was a stormwater facility with an embankment designed to meet criteria for a small dam established by the Dam Safety Office of Ecology. This facility included a buried treatment vault and more than 2,700 feet of pipeline. A particular challenge for this facility was analyzing groundwater conditions concerning stability of the pond base and use of Portland cement-stabilized fill to enable embankment construction during the winter.