Beachwalk Force Main Emergency Bypass

Location: Oahu, Hawaii
Client Name: City and County of Honolulu, Department of Design and Construction
Date Completed: 2006
Construction Cost: $45,000,000
Disciplines Applied: Water & Wastewater Engineering, Surveying & MappingPlanning & Permitting

Project Description:

Faced with the possibility of a repeat of a recent break of the existing 42” Beachwalk Force Main (FM) that resulted in a major sewage spill, the Mayor of Honolulu requested that an emergency temporary line be installed within 90 days. RMTC led the design team in this emergency design build effort that included Hawaiian Dredging Construction Co. as the Contractor and City project managers facilitating the progress of the project. With the cooperation of State, Federal and City agencies and cooperation between all members of the design build team, this 6,000 lineal foot, 42” ID bypass line was placed on line in 90 days.

The bypass project was constructed in two phases.

  • Phase One was the portion from the mauka bank of the Ala Wai Canal to Ala Moana Park. Phase One also included installation of temporary pumps along both sides of the Ala Wai Canal to intercept and divert sewage flows from the existing pump station to the new bypass pipe. This provided a “safety net” until the second phase is completed.
  • Phase Two was construction of an underground pipe by launching a state-of-the-art microtunneling machine from a pit on the mauka side of the Ala Wai Canal about 1,000 feet along Kaiolu Street to the Beachwalk wastewater pump station makai of Kuhio Avenue.

RMTC planners prepared an emergency NPDES permit for the emergency repairs. Surveying was also provided by RMTC