The Cortez Sanitation District board of directors heard the murky results of a field study conducted near a sewer line in the East Seventh Street area.
Last week, Jon Butler, of the engineering consultant firm Trautner Geotech, told the board that a recent study he did had revealed a sinkhole on the west side of a lift station, which conducts sewage uphill under pressure.
The hole is collecting large amounts of stormwater, which could wash away support for the sewer and its nearby access road, and any attempt to drain the water and remove the sinkhole would be extremely expensive, Butler said. The board members agreed to monitor the hole and start working on a “contingency plan” in case it causes damage in the future.
Butler said his study showed the sinkhole was likely caused by excavations for a small coal mine in the area, which had been filled in many years ago. He also said a few other cracks in the ground had appeared near the lift station.
The stormwater that drains into the sinkhole and cracks could damage the sewer, he said, but they appear to have existed in the area for at least a few decades without doing so. It’s also not clear where the water is draining out.
“The difficult thing about this whole situation is, trying to predict what could happen is close to impossible,” Butler said.
There are ways to keep more water from running into the hole, but Butler said they would all be complex and expensive. He said fixing the damage to the ground near the sewer would not be practical.
Board member Ernest Maness said he was worried by the report’s suggestion that more stormwater is draining into the sinkhole than in past years.
“I don’t think it’s something you want to ignore, because if it was on the surface for the last 50 years, and it’s underground in the last two years, it could do some tremendous damage,” he said. “I’d like to consider thinking about ... alternatives, what we can do to try and alleviate or remedy the situation.”
Other board members expressed similar sentiments, but they agreed that immediate action probably wouldn’t be necessary.
Board president Ryan Griglak suggested they watch the area for any new sinkholes, and discuss in future meetings what to do in case the problem gets worse.
Butler said his “gut feeling” is that the sewer will stay put for a while.
During the meeting, the board also approved a preliminary 2018 budget proposal and reviewed potential changes to the district’s rules and regulations, to be voted on at a later meeting.
A water billing agreement with the city of Cortez was tabled because the city had not yet sent the board a signed version of the agreement.