EAST HONOLULU — Starting as early as next week, motorists should take an extra dose of patience with them when they travel on Kalaniana'ole Highway. That's when repairs are slated to begin on the aging sewer line from Niu to Hawai'i Loa Ridge.

"We're planning to close one lane at a time," said Eric Takamura, city Department of Environmental Services director. "I haven't seen a detailed plan, but it won't be of the magnitude like when they did the temporary bypass. There may be times when they do the replacement line that traffic may be as bad."

Workers will use 12 test bores in various spots from Kawaikui Beach Park (near Pu'uikena Drive) and Niu'iki Circle (near the Niu Valley Shopping Center) to find out what kind of soil is under the highway. The soil will then determine the directional drilling method the city has chosen to use to replace the old sewer force main, which dumped raw sewage onto the highway and into the ocean in February 2005. The city erected an above-the-ground bypass line stamped with the words "live sewage" shortly after the line broke three times in one month.

The line collects untreated sewage ranging from Kuli'ou'ou to the east and from as far away as Kalani High School to the west. It then pumps the sewage through larger pipes that carry it to the sewage treatment plant at Sand Island.

The directional drilling method involves an underground drill that makes a horizontal hole deep below the surface and the existing pipelines. A pipe is then inserted into the hole and connected to the sewer system. The other method would be to trench the road and place a length of pipe and then repave the roadway. With the directional drilling method, the project could be done in as little as eight months, rather than three years, Takamura said.

Residents experienced nightmarish traffic snarls, with cars backed up sometimes for hours while the bypass line was being installed during evening pau-hana traffic hours.

"Obviously, it has to be done, especially given what has been going on in the Ala Wai," said 'Aina Haina resident Tim McGivern. "Clearly, it should have been done a long time (ago) when the state widened the highway. It defies logic why the city waited until after the highway work was done to do this."

Armed with information on the soil content, the contractor can probably begin work in September on drilling for the new pipeline, Takamura said. The city says it will make sure the community is kept abreast of the construction details and will make presentations to the neighborhood boards. A meeting at the Kuli'ou'ou/Kalani Iki Neighborhood Board has been scheduled, said Bob Chuck, board chairman.

Reach Suzanne Roig at sroig@honoluluadvertiser.com.