WOC was the prime consultant responsible for the overall planning, engineering and design of the force main. The project successfully demonstrated the feasibility of a large dual pipeline installation using horizontal directional drilling and micro-tunneling in difficult soil conditions with no adverse environmental effects and minimal socio-economic impacts.
Horizontal directional drilling was used to install two parallel 34-inch high density polyethylene (HDPE) pipes within 46-inch steel casings for the replacement force main’s 3,100-foot crossing beneath Honolulu Harbor. This was the longest and largest pipeline ever installed by horizontal directional drilling methods. The use of horizontal directional drilling methods for the channel crossing was highly effective in avoiding disruption to the Honolulu Harbor operations and water quality impacts to the Class A waters.
WOC also provided services for the rehabilitation of the Hart Street Wastewater Pump Station. Originally, the City planned to construct a new pump station. However, WOC presented an alternative to reconfigure and rehabilitate the existing pump station that could achieve significant cost savings. The redefined goal of the project was to achieve a station that could reliably accommodate the existing and future flows, minimize the possibility of spills, be cost-effective, easy to maintain, and could be constructed with minimal disruption of service.
Services Provided: Civil Engineering, Planning
AWARDS
2003 National Project of the Year, Environment More than $10 million, American Public Works Association
2002 Engineering Excellence Grand Conceptor Award, American Council of Engineering Companies of Hawaiʻi
2002 National Engineering Excellence Honor Award, American Council of Engineering Companies
2002 Outstanding Civil Engineering Achievement Award of Merit, American Society of Civil Engineers, Hawaiʻi Section
2002 Project of the Year, Environment More than $10 million, American Public Works Association, Hawaiʻi Chapter
