MANHATTAN, Kan. -- Officials will temporarily close the stilling basin at Tuttle Creek Lake in Manhattan, Kansas, due to two construction projects at the lake.
The stilling basin is set to temporarily close on May 28, 2024, and will be closed for three to four months, June through September, while the first construction project, a rock overlay project, also known as riprap, is completed. However, the duration of the project will be dependent on weather and the level of the lake.
Riprap will be placed on the upstream side of the upper portion of the dam, as well as on both sides of the river channel below the dam. The areas being repaired consist almost entirely of rock that was placed 60 to 70 years ago during original construction of the reservoir. After several decades of freeze and thaw cycles, as well as erosion due to the 2019 flood event, the riprap is due to be repaired and replaced to minimize erosion from future events.
Riprap was placed in early winter 2023 until the riprap stockpile was exhausted. Quarry production began again on April 15, 2024, and the newly produced supply is now being delivered to the placement sites at the lake. Placement of riprap will be on the upstream side of the dam. Of the total 7,500 feet of riprap, there is about 800 feet left to be placed on the dam.
The placement of the lower portion of rock and grouting in the downstream area will require the river channel to be pumped down and dewatered for almost a month during this phase of work. Currently, the dewatering period is scheduled to occur in July 2024, after the Independence Day holiday.
The only impact this project will have on Tuttle Creek State Park will be closure of the west entrance where the park entrance road passes though Outlet Park, which is managed by the Kansas City District, U.S. Army Corps of Engineers.
The second construction project affecting the stilling basin at Tuttle Creek Lake is a gate liner repair project. This project includes replacement of two large steel liner plates immediately below the flood control gates in the control tower.
During a routine inspection in fall 2020, it was discovered that one of the liner plates on the west side of the tower had failed and a portion of the steel plate was found in the stilling basin below the dam. The liner plates were redesigned and will be replaced on gates one and two.
The gate liner replacement below service gate one was started in August 2023, and was completed in April 2024. The contractor is scheduled to return in late July or early August 2024, and will complete the same work below gate two. Work will continue into the fall and early winter of 2024. The work on the second gate is expected to be completed by the end of 2024.
The gate liner repair project requires a crane to periodically lower and raise materials and equipment into the stilling basin, where it is then moved to the active construction areas. During crane operation, the basin area will be closed to all public access. Short-term closure of the stilling basin will be announced on the Tuttle Creek Lake Facebook page: https://www.facebook.com/USACETuttle/.
None of the construction work for these two projects has any connection or correlation to the proposed Water Injection Dredging project that is planned for 2025.
For more information on the temporary closure of the stilling basin or for more information about these projects, please contact the Tuttle Creek Lake project office at 785-539-8511.