Water has been a popular topic among many citizens lately with the city’s discussions on the possibility of selling additional water out of the lake.
To get an update on where the study by Black and Veatch was and answer any questions of the Commissioners, the El Dorado City Commission held a work session with Dick Kaufman and Andrew Hansen of Black and Veatch Thursday evening.
Kaufman began with a brief history of El Dorado Lake, talking about where it has been and why they were doing the study. The lake was completed in 1981 and the city owns the water storage in the top 43 feet of the lake.
“That is 50 billion gallons of water,” Kaufman said.
He went on to say more than 11 billion gallons of water pass through the spillway each year, and that is above the current customer demand. The citizens of El Dorado use half a billion gallons of water a year, with the total usage for all customers in 2012 being 3.8 billion gallons.
“Only 7 percent of water available is being used for consumption or value added,” Kaufman said.
Today the lake is down a little over 4 1/2 feet, while Cheney Lake is down 7 1/2 feet in this drought.
“We really came to the conclusion with looking at the facts of the lake the lake is a very strong resource for the city of El Dorado and it is not being utilized to the fullest of its potential,” Kaufman said.
Hansen then talked about yield analysis, including how much water is there. They had done a computer model similar to what the Kansas Water Office had done by looking at the last 57 years of rain records, but made some enhancements to it, including evaporation and sedimentation.
“What the results yielded was there is in excess of two times the amount of water in the lake than the city of El Dorado needs even in the most extreme drought,” he said. “We looked at other options of using water from the lake. We zeroed in on using as much water as we thought reasonable. The five feet was kind of a threshold for protecting uses of the lake for recreation.”
He said above that five feet threshold they are looking to use an additional 30 million gallons a day (mgd) in addition to what the city is already using. The city could go 66 to 67 months straight taking an additional 30 mgd without going below that five feet.
“Overall, the yield of the lake is capable of supporting a population of around 250,000 even under the most severe drought,” Hansen said. “There are huge opportunities. It’s a renewable resource. It is something you have to monitor and use, but it is a great resource. You need to use it to the best of its intended usage.”
Page 2 of 4 - Selling water would not only allow the city to utilize the resource but also reinvest the additional funding coming in to extend the lake’s life beyond the 100 years for which it was intended.
"We've come to the conclusion having looked at the yield analysis, we've and having looked at various scenarios to deliver water, and the next step is to look for concurrence from the commission to look at a plan to deliver water to the city of Wichita, which is the obvious customer," Hansen said.
Commissioner Nick Badwey asked if they could sell that much water and not drop below five feet.
Hansen said that was looking at if the area experienced a drought similar to the 1950s and was drawing out twice as much water as they currently do, they could still make it through the drought with water, but it the lake would drop below more than the five feet.
The model showed them taking out 30 million gallons per day (mgd), plus the current contracted amounts any time the lake is above within five feet of conservation pool, then once it reached dropped five feet in the model, the additional 30 mgd was turned off and only the current use was still taken out. That allowed 30 mgd to be drawn 78 percent of the time, with no additional water being sold the other 22 percent of the time.
Herb Llewellyn, city manager, said it was the commission's choice if they wanted to sell water below five feet.
Commissioner David Chapin said what he thought everyone was wanting to know was if they took 30 mgd out a day over 30 days with no new rain, how much would the lake would drop, to which he was told 4 1/2 inches a month. The city currently uses about 1.5 inches a month from the lake.
Kurt Bookout, public utilities director, said during the summer evaporation rates are 10 to 12 inches a month.
To refill the lake would depend on the precipitation event. The current snow has raised the lake an inch or two, but everything was extremely dry before that.
“We have seen two to three inch rains bring the lake up a foot or two,” Bookout said. “It depends on the runoff.”
That includes the 250 miles of watershed above the lake that feeds into the lake through tributaries as well as alluvial flows.
Commissioner Shane Krause went on to ask about a different affect, global warming, something he said gets a lot of questions.
“This new drought may never go away the way global warming is going,” he said. “What’s your opinion on that?”
Hansen said there has been a lot of discussion about global warming.
Page 3 of 4 - “As engineers we focus on facts that we can quantify,” he said.
They have seen more of an impact from the way people use water and water conservation.
“We’ve seen a 10 to 20 percent per capita decline because of people using water smarter,” Hansen said. “I think that is a general trend.”
“Would global warming have any affect on the life of the lake?” Krause asked. “To me, global warming is more of a long-term thing.”
Llewellyn said there has been a change in the rainfall since he city has been keeping track.
Bookout said 30 years ago the average precipitation was 32 1/2 inches, while from 2012 back 100 years it is about 35 1/2 inches.
“We’ve had a very wet last 20 years,” Bookout said. “That is not to say it will continue because weather is cyclical. Long-range climatologists say global warming will impact, but they don’t know how.”
Krause went on to ask about the five foot threshold and if that was set because it could affect boat ramps and launches. Bookout said in 2007 the lake was down six feet below conservation pool because of Mother Nature, which also is the lowest the lake has ever been since it was built.
“Both marinas were fine,” Bookout said. “There were some boat slips at the back that were unusable. The sailboat marina went in and did some modifications so they could weather a drought so they could still function if the water dropped lower than that.”
The five foot limit was also set to preserve the drought supply for the city of El Dorado and current customers.
“The vision of selling additional water was always really aimed at that 11 billion that is going through every year,” Llewellyn said. “Normally it’s the flow out of that dam.”
Other questions pertained to if the city could work with the Corp of Engineers to sell the three foot above pool or retain more water at certain times.
Llewellyn said they could talk with the Corp but there are limitations on changes that can be made, although there is some room locally to make some decisions to operate within a range.
Some of the Commissioners and city staff also attended a drought planning initiative this past week in Wichita.
“What I really heard was it seemed there were several (Wichita) commissioners interested in looking at El Dorado not as a primary source but as an additional source of water,” Mayor Tom McKibban said. “It has to be a combination of a lot of different projects.”
Page 4 of 4 - The city of Wichita has not made a formal request to El Dorado to purchase water. And buying water from El Dorado was not even one of the strategies presented.
McKibban said now he would want to see a plan of how they would sell water, the rules associated and the cost benefits. He wants to give the public time to look at that and give feedback.
Llewellyn said the next step is to bring more information back to the commission that outlines what they are thinking.
Commissioner Bill Young said El Dorado is fortunate with its resource in the lake.
“This does provide an opportunity to reach out and collaborate with neighboring communities,” he said. “It also provides some additional funding to reinvest in the lake.”
More information about the financing for the lake will be presented at Monday’s Commission meeting.