Straight into the ground

By JOHN McCALLUM

Managing Editor

Cheney typically averages about 700 gallons per minute in water usage from October to about mid-May, an amount easily produced by the city's two oldest wells located next to the Pence Union Building on the Eastern Washington University campus.

So when water department personnel began seeing other pumps kick on in late December/early January in order to meet demand, they knew they had some problems somewhere in the system.

Public Works Director Todd Ableman said leak detection work done in the fall had alerted them to some possible issues with portions of the more than 46 miles of city water piping underground. But with nothing showing above ground such as excess water running down a street or portions of asphalt actually bucked up from the pressure, and late-winter snow covering the ground in February, there was little city crews could do.

What crews finally did find once the snow began melting away was eight locations in the city with leaks ranging from 10 gallons per minute (gpm) to over 200 gpm - leading to city pumps having to produce approximately 1,050 gpm since late December.

The leaks not only resulted in water losses and excess wear and tear on pumps normally kept dormant until irrigation season, but also lots of calls of brown water from residents as pumps kicked on, disturbing the iron content of Cheney's water that might normally accumulate at the bottom of the wells while not in use.

Half of the leaks, accounting for over 300 gpm, were north of Elm Street in an area with a lot of steel pipe. The largest, 200 gpm, was at 5th and Elm where an eight-foot section of pipe containing a number of pinhole leaks and one the size of a golf ball had to be removed. Other locations such as at North 5th and Oakland and North 3rd and Oakland required less drastic repair measures.

Ableman said the location of leaks was determined mainly by crews from American Leak Detection of Spokane driving around town and using special equipment to listen for them. In some places, melted snow and ice provided indications of the location since the water in Cheney's aquifer is a relatively warm 60-70 degrees.

Red Diamond Contracting was hired to repair the leaks, work that totaled over $60,000. The work took about three weeks to complete, and as it did, the wells that were coming on - No. 8 and No. 5 - began to remain shutdown while reservoir levels rose back to normal, close to 29 feet.

While much of the city's mains are now PVC, a material fairly resistant to mineral impacts, about 17 miles of water mains are steel construction. Ableman said the electrolysis process from the clay layer where the pipes are installed can lead to their deterioration from the outside in.

Ableman said it's likely more of the city's steel water piping contains smaller leaks than those recently found, leaks that could eventually develop into larger issues. The city's goal is to eventually upgrade all the steel pipe, most of which is six inches in diameter, in the city to eight-inch PVC, mainly to help fire flow. The challenge to doing this is the cost - about $1.85 million per mile of pipe.

"We can do a lot of repairs in the meantime, but it's expensive, that's just the reality we live in," Ableman said. "It's almost cheaper to go out and do new construction."

For now, the city will rely on Community Development Block Grant funding to repair small sections of water main. Of particular concern for Ableman is the area north of Elm, with previous work having taken place around North 3rd and Oakland streets to rectify continual water leaks there.

"Our attention is now on Elm," Ableman said. "We'll probably see a CDBG project there soon."

John McCallum can be reached at [email protected].