COLUMBIA —Water fills cracks, crevasses and caves in a limestone formation just beneath Columbia. Ten city wells designed to pump drinking water dot the land above this subterranean water supply, but the city only uses two of them.
Until the 1970s, this was the source of Columbia's water. As the city grew, the demand for water became so great the aquifer couldn't keep pace. The city shifted its water needs to a different groundwater source in the McBaine bottoms near the Missouri River.
More than 30 years after the wells in the city were abandoned, plans are afoot to return two more of them to service by siphoning water from existing supply lines from McBaine to Columbia and pumping it into the wells.
The water would be on reserve in case something like a power outage disabled the treatment plant at McBaine or if water usage in Columbia spiked for a few days in the hot summer months. The plan would further strengthen the city’s backup supply by providing enough water to accommodate the city’s needs for about a day.
The city already stores water in two wells this way. By adding two more, the city could draw between 8 million gallons a day from the four storage wells combined until it used up the 30 million gallons stored in each well, John Betz of the city's Source Water Protection Plan Task Force said.
In the winter, Columbia uses about 12 million gallons of water a day. That number edges closer to 20 million gallons in the summer, Floyd Turner, manager of water operations for the city, said.
The task force is the group recommending the new use for the old wells. When the group first started meeting, most members expected to recommend pouring concrete down the pipes of the old wells and formally abandoning them, member Tom O'Connor said.
This had been the conventional wisdom from the Environmental Protection Agency and Department of Natural Resources after a wave of abandoned rural wells that were seen as potential pathways for surface spills and contaminants to reach drinking water.
"These aren’t little abandoned farm wells," O'Connor said. "These are municipal wells that we invested a lot of money putting into the ground."
O'Connor said the water in the limestone underneath Columbia is a little higher in quality than the water at McBaine.
"The likelihood is it's a notch better, not a world better, but a notch," he said.
But since the water from McBaine will be treated before it's put into the wells, it won't have to go through as extensive of a treatment process as water drawn straight up from the wells, Turner said.
MU gets its water from the limestone aquifer underneath Columbia, but doesn't use the city wells to get it. Todd Houts, MU's representative on the task force, said MU's water supply probably would not be affected by the changes to the city’s old wells because the systems have separate piping.
The storage wells will function similarly to water towers, but they can be used to store water for longer periods of time and store significantly more water.
"The water tower we have on Walnut (Street) has 1 million gallons," Betz said. "Now picture a 30 million gallon water tower."