Photo By Lawrence Brooks | A look from atop Tuttle Creek Dam on Aug. 23, 2024, where the dewatered outlet channel...... read more read more
Tucked alongside the native tallgrasses of the Konza Prairie within the undulating Flint Hills of Riley and Pottawattamie counties in northeast Kansas, is the Tuttle Creek Dam and Lake. This engineering marvel of the midwestern United States, is a 7,500-foot-long earth and rockfill dam that chokes off the Big Blue River, creating the second largest reservoir in Kansas with a total capacity of over 2.1 million acre-feet of water.
It was designed and constructed by the U.S. Army Corps of Engineers, Kansas City District and completed in 1962 with the primary focus of controlling flooding. The threat of a major flooding event from Tuttle Creek dam could affect around 100,000 people downstream, with an estimated loss of life of between 1,000 and 10,000 people. Additionally, damages to infrastructure and property could exceed $250 million.
Howard Johnson is the current project manager for the Tuttle Creek Dam project. He said these factors are why the work to protect the dam’s integrity is vitally important.
“I will tell you that, all the contracted workers out there and our USACE team, we take these jobs very seriously,” Johnson said when referring to the danger of flooding downstream communities face if this work is not done properly. “I mean that's something that we
don't ever want to see. So, we do all these small projects to make sure that in the future nothing dramatic happens.”
The Tuttle Creek Dam project began in the fall of 2022 to address damages to key components of the structure that were found after a periodic five-year inspection in 2020. Brian Twombly is a hydraulic engineer for the water management section of the Kansas City District, who is also on the project team. He said although most Kansans adore the lake for the recreational resources it provides (boating and fishing), it has other more important functions that sustain human life and support local economies that the public sometimes ignores.
“Another main use is water supply since the cities of Topeka, Lawrence and Kansas City, Kansas, draw water for city and industrial uses,” he said. “Turtle Creek Lake can also support navigation on the Missouri river, so we can make releases to help support that. It's not used every year, but it's available to help some flows there.”
The critical infrastructure project is one of many the Kansas City District is working across the region, and it’s scheduled for completion near the end of this year. Travis Blinkiewicz is a project engineer for the Fort Riley resident office construction division. He said getting this job wrapped up before the winter sets in are purposeful to meet USACE material specifications.
“We don’t accept rock between October and April because they don't want anything quarried in that time frame due to the freeze- thaw cycle,” he said. “The constant change in temperatures affects the strength of the rock. So essentially it doesn't break down more once we get it.”
Casualty Births Repairs
During what was dubbed “The Great Flood of 2019” the Kansas City District experienced a record amount of flooding between March and December – due to unusually heavy snowfall in the Missouri River Basin in winter of 2018. High temperatures to open the spring exacerbated the issue by causing a rapid melt of the winter snow before the ground underneath was able to thaw and absorb the water. Naturally, the many streams and tributaries upstream of Tuttle Creek was the only place for the runoff to go.
These phenomena coupled with near-record rainfall in the subsequent spring and summer of 2019, contributed to the unprecedented length of the flooding event. The slow filling of the dam created a looming threat of water going over into the emergency spillway, which put an abnormal amount of stress on dam infrastructure and the USACE employees that maintain it.
“We were making a lot of high releases through the outlet channel during that year to mitigate the chance of flooding,” Blinkiewicz said.
USACE employees who monitor the structural integrity or the water levels of Tuttle Creek Dam, knew the record flood year and the unusual amount of high velocity water releases, had the potential to cause damage.
“Normal releases range from 300 to 1,000 cubic feet per second. But after a flood, we could be releasing up to 35, 000 cubic feet of water per second,” Brian Twombly said. “Typically, each year we probably get between seven to 10 releases. It's pretty rare when we start getting higher than that, and I think that year we had 12 or more.”
After a standard periodic dam inspection in October of 2020, their fears about the negative impacts the water releases may have had, were confirmed.
“When the [inspection]crew dewatered the lake to inspect the outlet channel and structures, they found severe erosion on a lot of the overlay riprap,” Robert Dye said, who works in construction control at USACE’s Fort Riley Resident Office.
Riprap, commonly known as shot rock or rock armor, are human-placed rock or other hard material that are used to insulate and protect shorelines against water, waves or ice erosion. Dye said that wasn’t the only significant problem they found.
“The water releases were so rough; they also found the stainless-steel release gate liner at the bottom of the outlet channel,” he said.
The damages to the protective rock face underneath the riprap, the riprap itself and the outlet gate liner, severely degraded the integrity and safety of the dam. These issues became the impetus for the Kansas City District to begin the Tuttle Creek Project repairs back in the fall of 2022. The $16-million-dollar contract was awarded to ESI Contracting Corporation in Kansas City, Missouri, and consists of replacing the riprap and grout on the full-length of the dam on the upstream side (phase one), then repairing the release gate liner and replacing the damaged riprap and grout on both banks of the downstream outlet channel (phase two).
Twombly said the downstream repairs, which started on Aug.1 of this year and required the complete dewatering of the outlet channel. he said phase two of the project is by far the most difficult because of the stress involved with putting heavy restrictions on water management.
“To put the riprap in below the waterline, we had to turn off all water releases and by the contract specifications, we could only do that for 28 days. That's a pretty big deal to turn off releases at a major dam like Turtle Creek,” he said on Aug. 23 while walking the muddy bed of the outlet channel. “If we did stop work because of a big rain during the construction period, we could lose a lot of the work that was already done. So, there are lots of tough decisions, but they're on schedule and we're toward the end of the portion of the project on the outlet channel.”
Federal Dollars Uplifts Local Businesses
The Kansas City District prides itself on its commitment to their stakeholders and the many contractors they partner with to do the unseen work to improve the lives of American citizens of this region. Alan Wolfe is the owner of ESI Contracting Corporation of south Kansas City. He said, he appreciates the level of cooperation he’s gotten from USACE staff.
“The core project people on site who are Brian McNulty, Travis Blinkiewicz and Robert Dye, were just very good people to work with to help coordinate the project and have a successful conclusion to our efforts in the channel,” Wolfe said.
Wolfe also included the fact that the $16- million contract his company has been entrusted with, is a prime example of how federal contracts help local businesses grow.
“We're thankful for the work, thankful for the partnership since the flow of money goes to our trusted vendors and subcontractors,” Wolfe said, whose father started the heavy construction company back in 1952. “So, all the trucking, concrete, aggregate and all our fuels are purchased from local people in the area. The dollars that that are generated by that contract are definitely going back into the local economy here and it helps feed a lot of families.”
The completion date for the entire Tuttle Creek Project contract is Dec. 1. Project Manager Howard Johnson said with the quality of work and professionalism he’s seen in this public- private partnership thus far, he’s confident the contractors will hit that target on time.
“Right now, there have been no change orders submitted and everything looks to be on schedule,” he said.
| Date Taken: | 09.26.2024 |
| Date Posted: | 09.26.2024 14:27 |
| Story ID: | 481871 |
| Location: | KANSAS, US |
| Web Views: | 24 |
| Downloads: | 0 |
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