.FERNLEY, Nev. (AP) – The failure of an earthen embankment on a century-old irrigation canal that flooded this growing town has federal water managers concerned about the safety of nearly 8,000 miles of similar aging canals across the West.

The January breach of the Truckee Canal flooded nearly 600 homes, making Fernley a state and federal disaster area.

“As a result of this we are taking a look at our canals with a little more scrutiny,” said Jeffrey McCracken, regional spokesman for the Bureau of Reclamation in Sacramento.

The review is no small task. The bureau owns 7,911 miles of canals in 17 Western states, the vast majority of them managed and operated by local irrigation and water districts.

And the review is made more urgent by the change in demographics across much of the West from rural to urban. Hundreds of Fernley homes sit along the Truckee Canal, which just a decade ago ran primarily through farm fields.

“Fernley is the perfect example. The canal has been here 100 years and all the sudden 500 homes get constructed next to it,” McCracken told The Associated Press.

Crews started digging the Truckee Canal in 1903 with mules and steam shovels. In 1960, Fernley’s population stood at only 654; today, the town serves as a bedroom community of Reno, 30 miles to the west, and the population is about 20,000.

That change will control the priority of the canal surveys.

“We will focus initially on canals in those urbanized areas. There’s a lot in the Phoenix area,” McCracken said. “The other real old one out West is up in the Klamath Basin” in northern California and southern Oregon.

“The tragic situation that occurred on the Fernley canal is an impetus for these other irrigation districts and water districts to get on top of everything they can. And I’m not implying they are not, but let’s go look.”

Ernie Schank is president of the Truckee-Carson Irrigation District that maintains and operates the canal for the bureau.

“We have to realize that the canal was built in 1903. The standards were not the same then as they would be if you were building a canal through a dense population like has grown up in Fernley,” Schank said.

The engineers who investigated the Fernley flood concluded the main reason of the failure was the embankment had been riddled with rodent burrows, some up to 25 feet deep. They also found:

• A lack of maintenance allowed the growth of numerous large trees whose root systems can weaken an embankment.

• Many of the pipelines taking water out of the canal were constructed by people “unaware of proper construction techniques”

• Off-road vehicles had been allowed to damage the canal banks.

• Data on the geology of the soil and bedrock beneath the canal was “poor to nonexistent.”

The 32-mile-long canal takes water from the Truckee River, which flows out of Lake Tahoe, south to the melon and alfalfa fields around Fallon. Some 3,000 water users depend on the canal for their crops and livestock.

Economic studies estimate the value of those goods and related businesses approach $100 million.

A team of geophysicists, hydrologists, engineers and geologists estimated the cost of repairs will range from $28 million to line half of the canal with riprap to $390 million to replace the entire canal with a 16-foot-diameter pipeline. Permanent repairs are at least two to three years away and that’s only if Congress kicks in tens of millions of dollars or more, said Dave Gore, regional engineer for the bureau.

The Truckee canal was shut down after the Jan. 5 failure and sat empty for more than two months while experts examined it. The bureau reopened it on March 14, but at only 20 percent of maximum flow until the irrigation district makes improvements.

Ranchers welcomed the return of the water, vital in a high desert region that averages only about 5 inches of precipitation a year.

Angry townspeople, however, expressed outrage that the bureau would permit any water to flow before new safety measures and procedures were put in place.

“The conditions that caused the levee to break are still there,” Judy Kroshus said. “The only solid spot is where it broke before. Everything else is in the same condition.”

Kroshus is among more than 100 flood victims who have filed class-action lawsuits against the irrigation district, bureau, city of Fernley and others. Among other things, their lawyers want restrictions on the water flow in the canal.

Work began on the Truckee canal in the same year as the canals in the Salt River Project serving the Phoenix area.

“It started out mostly for irrigation for farmers and the city kind of grew up around it,” said Patricia Cox, spokeswoman for the bureau’s Phoenix area office.

Unlike the Truckee Canal, however, the 1,400 miles of main canals in Arizona are now lined with concrete although some irrigation ditches are still earthen.

“Some are in fair condition but most are good, so we don’t have any canals that we would have any concern about,” Cox said.