Hawaiian Electric Co. is proposing to spend an estimated $14 million to replace two old high-voltage cables that run across the bottom of the Ala Wai Canal with new lines installed deeper underground.

The company announced the plan Friday and said the new cables to serve Waikiki will accommodate the state’s plan to dredge the canal in mid-2018.

Existing 46-kilovolt cables were installed in 1956 and 1990 straight across the canal to Kaiolu Street where HECO has a substation. A preliminary environmental report from the state describes the cables as being 9 feet below sea level.

The replacement plan would involve extensive street trenching on both sides of the canal — along Hihiwai Street, University Avenue, Kalaimoku Street, Ala Wai Boulevard and Kaiolu Street — but would run 50 feet below sea level under the canal through drilled holes.

Though there will be short-term disruptions including lane closures, HECO said the project is its best option and will remove cables that are at risk of damage during dredging projects.

“Hawaiian Electric has extensively considered alternative routes, above and underground, and determined this is the most cost effective and least disruptive option,” the company said in a statement.

A map of the proposed cable route is available at hawaiianelectric.com/alawaicanal.

HECO said it will produce an environmental assessment for the project and already has done archaeological and cultural studies along with collecting feedback from the community and descendants of families who lived in the area.

The cable replacement project is subject to approval by the state Public Utilities Commission. If approval is granted, the utility company hopes to begin work late in 2017 and finish in mid-2018 before canal dredging begins.