Wichita officials are recalculating the date that Cheney Reservoir will quit supplying water to the city, in the wake of recent rains and snowfall that have raised the lake level 4 percent.
But they have concluded already that the spring rains will make little difference in the date that the lake will quit supplying about 60 percent of the city’s annual water usage.
On Monday morning, the reservoir was 62 percent full, said Ben Nelson, strategic services manager for the city, in an e-mail. That’s up from 58 percent on Feb. 26, when public works officials told the City Council that the drought will cause the lake to quit providing Wichita water in August 2015.
Nelson said Monday that the rains will push the August 2015 date back, but only by a little.
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“Obviously, we have data from the first couple months of spring that we are plugging into our water models,” Nelson said. “On its own, that water level increase of 4 percentage points would not add enough months to push the dry date for Cheney through the end of 2015.”
City officials have launched a conservation campaign, and an in-house review of the city’s own water usage is underway.
Other alternatives to conserve and grow the city’s water supply remain, including buying water from El Dorado Lake, a $5 million project to enhance the city’s Equus Beds well field in the Halstead area and punitive pricing, charging heavy water users at least 50 percent more per month in an effort to cut water usage by 50 percent.
Nelson said the city is monitoring current water levels at Cheney through the U.S. Army Corps of Engineers.
The lake’s remaining life is calculated with three main variables, Nelson said: weather conditions, usage patterns and supply resources. The August 2015 dry date, Nelson said, was “calculated by assuming that the current drought conditions continue over the coming years, without any reductions in the amount of water used.”
The final factor is the amount of water drawn from Cheney each year, and the city’s forecast models assume that water usage will remain the same.
“Any change in those variables is how we identify the length of supply extensions presented in our drought options,” Nelson said. “ We either have to have the weather change, reduce usage, or add supply, reducing the Cheney drawdown rate from its current 60 to 65 percent level, in order to increase the lifetime.”