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Archive for Sunday, March 11, 2012

Kaw Water Treatment Plant improvements begin

March 11, 2012

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Construction has begun on a $600,000 project to improve the reliability of the city’s Kaw Water Treatment plant, and planning is under way for a $7 million project that will involve trying to figure out the shifting sands of the Kansas River.

The city has shut down the Kaw Water Treatment Plant, Third and Indiana streets, for the month of March while crews replace several critical valves that are more than 50 years old.

“Because of their age, the valves don’t close all the way,” said Jeanette Klamm, a programs manager with the city’s Utilities Department. “If we ever had to isolate the plant for some reason, we couldn’t do that without some people who live near the plant being out of water.”

Crews are installing 36-inch valves and new piping in the front yard area of the plant. During the project, all of the city’s water is being supplied by the Clinton Water Treatment Plant in West Lawrence.

During the project, traffic on portions of Third and Indiana streets may be affected. The city’s bulk water station, where customers can pay to fill large, portable tanks, is closed for the month. The project is expected to be completed in early April.

But there is plenty of additional water plant work that will stretch throughout 2012 and into 2013. Utilities Director Dave Wagner said the city has begun working with Black & Veatch engineers to design a solution to a malfunctioning Kansas River intake that forced city officials to essentially shut down the plant several times over the last year.

Figuring out a solution for that problem will be complicated because it involves trying to predict how the sands of the Kansas River will settle.

“It is going to be a pretty significant effort,” Wagner said.

The Kaw River plant is designed to operate with two intake pipes in the Kansas River. One of the intakes has long been inoperable, and over the last several years sand has periodically clogged the lone remaining intake.

The city’s utility rate plan has about $7 million in its budget to build a new intake and hopefully improve the existing intake to the point that it can be used as a backup.

But first, engineers have to better understand the shifting sands of the Kansas River. That can be difficult enough in ordinary times, but Wagner said the construction of the new Kansas Turnpike bridges upstream of the plant have changed the dynamics of the river.

Following the construction of the bridges, for example, a large sandbar has emerged near Kansas University’s boathouse in Burcham Park.

“It is there now,” Wagner said. “Whether it stays there or not is one of the things we’ll try to figure out.”

The sandbar, though, is one of the few changes visible to the naked eye. Equally significant changes are happening on the bottom of the river. Wagner said contractors for Black & Veatch will be on boats in the river using electronic equipment to map the bottom of the river and measuring the velocity of the river’s flow.

In addition, engineers will have to predict the impact changes to the Bowersock Dam, which is just downstream of the plant, will have on the river. Plans call for an inflatable “rubber dam” to be installed on top of the existing dam. That will allow for higher water levels upstream of the dam, which will change the river’s sedimentation pattern.

Understanding the changing sedimentation patterns of the river will be important in determining what type of improvements are needed to make the river intakes work properly, Wagner said.

Wagner said he expects to start getting results from the study in the fall, but construction on a new intake likely would not begin until 2013.

Wagner said if problems with the intake do cause the Kaw plant to be shut down again, the city’s Clinton Water Treatment Plant is in a good position to serve the entire city.

“The Clinton plant can keep up with high demand,” Wagner said. “But it can’t keep up with a super summer peak that happens maybe once every five or 10 years.

“We feel like we have the Kaw intake reliable and cleaned out, but it is not in the condition we would like to operate under.”

Comments

Joe Hyde 2 years, 1 month ago

Since the day I first heard of the proposed second electric generating station at Bowersock Dam, I've wondered whether plans were in the works to raise the elevation of the dam (either by topping it with new concrete, or by using taller batter boards). The idea of an inflatable "rubber dam" never occured to me.

Since the second power generating plant is a commercial activity, once this "rubber dam" gets installed it will very likely be inflated to full capacity and remain inflated almost constantly, causing essentially a permanent elevation rise of Bowersock Dam. Heightening the dam creates a longer pool of slow-moving water upriver. (The slower velocity lets gravity pull sand and sediment particles down onto the riverbed causing increased buildup along with new distributions of sediment in areas upstream of the dam.)

The water intake structures at the Lawrence Westar power plant are already impacted by sediment changes caused by Bowersock Dam's changing batter board configurations. A permanently taller Bowersock Dam will force more frequent maintenance and possibly even water intake redesign work at the Westar plant. And farther downstream at Burcham Park, I can now only hope that a permanent raising of Bowersock Dam's elevation does not trigger sediment buildup amounts that lead to the City of Lawrence forever losing its ability to draw water from the Kaw for public and municipal use.

Bowersock's electricity buyers can always find ways to use less electricity. What the rest of us can't find ways to do is live without safe water.

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