A rock dropped in a municipal well in Bellevue 30 years ago has put a crimp in the city's water supply for long enough. The City Council voted last week to do something about it.
An engineering firm hired by the city recently submerged a video camera 138 feet into the 200-foot deep Chestnut Well on the south side of town and got a look at the rock. The camera operator tried to dislodge it, but was unsuccessful.
"It was lodged in there pretty tight," said engineer Steve Yearsly of Forsgren Associates, who presented the underwater photographs to the council Thursday.
Yearsly said the rock was dropped when the well was dug during the 1970s, before the well diggers had a chance to cap the hole.
"It's what people do when they see a hole in the ground. They drop a rock in to hear it fall," he said.
According to Yearsly, the Chestnut Well, which is used along with the Chantrelle Well on the north end of town for the city's municipal water supply, has pumped at less than its planned capacity for many years due to the rock. But he said the rock was not the only problem.
The camera showed a series of quarter-inch "screen holes" intentionally cut in the well casing when it was dug to allow water to fill the well. Due to the large size of the openings, the well pumps sand when capacity is increased above 350 gallons per minute.
Yearsly said the city needs the well to pump about 1,500 gallons per minute to match the capacity of the Chantrelle Well, thereby providing a back-up system in case one of the wells goes out of service.
Yearsly presented the council with two options to achieve that: Remove the rock and fix the Chestnut Well for $152,000, or dig a new one nearby. But even with repairs, Yearsly said, the Chestnut would still lag in capacity compared to the Chantrelle.
"The well was designed for a smaller town, with fewer people," Yearsly said in an interview.
The council authorized drilling of a new well beside the old one at a cost of $280,000. Yearsly said the work will be completed by the end of October.
Tony Evans: tevans@mtexpress.com
Bellevue Public Works Director George Tanner stands beside a municipal well that has been partially blocked for more than 30 years by rock stuck 138 feet down.
