Tim Ryan, tryan@wolfrivermedia.com
The city of Shawano has identified eight locations along Main Street at risk for water main breaks due to potential corrosion.
High levels of chloride in the soil were responsible for three water main breaks along Main Street since December 2010 and recent random soil tests found eight other spots where chloride levels are high.
The Shawano Field Committee recently approved adding $20,000 to next year’s Capital Improvement Projects budget to cover the costs of replacing stainless steel saddles in those eight locations. The saddles hold in place the service connection to the water main.
Random soil tests were done over the summer by Mach IV Engineering, of Green Bay. Out of 20 locations sampled, chloride levels above 500 parts per million (ppm) were found at three locations. Five others had chloride levels above 300 ppm.
Public Works Coordinator Eddie Sheppard said the stainless steel used in the saddles could start to deteriorate at chloride levels over 300 ppm. At levels above 500 ppm the deterioration is much faster.
Chloride levels in the area of the three water main breaks were in the range of 900 ppm, he said, adding that those kinds of levels are rare.
“That’s from years and years of street salt seeping into the soil,” Sheppard said.
The saddles were installed during the Main Street reconstruction project in 2002 and 2003, which stretched from the channel to the Mountain Bay Trail at Oshkosh Street.
The contractor on the project was Degroot Construction, of Green Bay, which purchased the saddles from Davies Water Equipment of Appleton. The saddles were manufactured by Smith Blair Inc. of Texarkana, Texas.
The eight problem areas discovered during this summer’s soil testing are scattered between the 200 block of South Main Street and 200 block of North Main Street.
Sheppard said the city is looking at replacing stainless steel saddles in those areas with either coated stainless steel or brass saddles. The work will probably be done in the spring.
“Stainless steel is the industry standard,” Sheppard said, “but chloride is like kryptonite for them.”
The first two water main breaks occurred in the 100 block of North Main Street in February 2009 and December 2010, only about 50 to 75 feet away from one another. The most recent was in the 200 block of South Main Street in September 2013.
It was initially uncertain whether there was a soil problem or the saddles were defective, but tests done by TPS Consulting Engineers, of Green Bay, found the saddles met metallurgical standards and had been properly welded in place.
City officials said the high chloride levels pose no health concerns because there is no contact between the chloride and the city’s water.