For the second year in a row, cyclists will have to take a detour along the portion of the American River Parkway that runs from the Campus Commons Golf Course to nearly Ethan Way and Cal Expo because of a levee-improvement project.

The project began Monday and could continue until Nov. 30 or later, said Todd Plain, spokesman for the U.S. Army Corps of Engineers Sacramento District.

Plain said bikers should not be inconvenienced by the approximately 3,300-foot detour, but implored them to be extra cautious because of the narrower width of the detour trail.

"The regular trail is 12 feet, paved with granite shoulders on both sides of about 3 feet," Plain said.

He said the alternate path varies between 8 and 10 feet wide, with a mowed dirt shoulder of 2 feet on each side. He said the path was being cleared of branches and weeds around blind corners early Monday.

The Corps, along with the California Central Valley Flood Protection Board and the Sacramento Area Flood Control Agency, will install seepage cutoff walls in the levee as part of the American River Common Features Program.

About 10 years ago, the three organizations began levee improvements along the American River, but workers encountered obstacles.

Stretches with utilities such as sewer mains and power lines had been skipped until more money and workers with specialized skills became available, Plain said.

Last year, the same alternate bike trail was opened because of construction work that needed to be completed near a 60-inch sewer main, Plain said.

"We had to go in and dig by hand to make sure none of the tools would nick the main," Plain said.

Plain said workers are now focusing on a 900-foot stretch of land with three sets of power cables above. Work will be done at night, when electricity use is at its lowest, Plain said. He said nearby residents need not worry about temporarily losing power. "The only problem might be the noise," he said.

After this portion of the project is completed, Plain said, workers will continue moving up the river, and this detour will "probably not happen again."

He said there are 30 spots along the river that had been skipped and will now undergo construction.

"Building a seepage cutoff wall is kind of an art," Plain said.

The process involves mixing water and a clay substance called bentonite. Plain said workers dig a trench about 3 feet wide and 60 to 70 feet deep while pouring in the mixture, which keeps the trench from collapsing inward.

An additive – sometimes cement – is later added to the mixture, which causes it to harden. Workers can wait up to a month to cover the newly hardened wall.

Plain said that "while nothing can completely eliminate the risk of water leakage, we're doing the best we can to limit it."

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