Honolulu has awarded more than $175 million in contracts for a sewer tunnel mandated by the U.S. Environmental Protection Agency and the state Department of Health.

The city announced Tuesday that the contracts were awarded for the Kaneohe-Kailua gravity sewer tunnel project to the joint-venture group of Southland Contracting Inc. and Mole Construction Inc., and local construction management firm Bowers + Kubota.

The sewer tunnel will fulfill a portion of a federal consent decree to implement wastewater remediation projects on Oahu in the next 25 to 28 years.

The project involves constructing a 3-mile tunnel from Kaneohe Wastewater Pre-Treatment Facility to Kailua Regional Wastewater Treatment Plant.

City officials said that over the last two years, they have hosted community meetings about the project and, based on that feedback, the middle portion of the project’s alignment was moved further from residences. The tunnel now runs behind the Board of Water Supply Reservoir near Mokapu Saddle Road. 

Southland Contracting is a tunnel excavation and wet-utility installation company, while Mole Constructors is involved in underground civil construction, according to the city.