Chase State Fishing Lake, located two miles west of Cottonwood Falls, Kansas in Chase County, is a 109-acre lake with a total storage capacity of 1,950 acres. The lake’s dam was first constructed in 1937 and was then raised in 1955.
In 2017, KDWPT contracted Benesch to provide consultation on repairs to the lake’s outlet tower. Since the construction of the tower in the late 1930s there had been no major inspection or repair projects performed.
Benesch inspected both the outlet tower and the 24-inch diameter corrugated metal pipe (CMP) that is drains the lake from the inlet structure to the tower, and from the tower to the outlet structure. In order to inspect both the 24-inch CMP from the inlet structure to the tower and the tower itself, a plug had to be inserted in the inlet structure to allow for the tower to be drained of water.
This required Benesch to coordinate with a local utility dive team to first locate the inlet structure, and secondly to dredge approximately ten feet of material that had settled over the structure. Once the dredging operation was completed, the dive team installed a metal plate, designed by Benesch, over the inlet structure allowing KDWPT to open the gate valve within the tower to drain it.
Once the tower had been drained, a CCTV camera was inserted into the 24-inch outlet and inlet CMPs and videos were made to ascertain the condition of the entire lengths of both CMPs. Once that operation had been completed a 3D scanner was used to video the interior of the tower itself allowing Benesch to determine what repairs would be necessary to the interior wall, gate valve, valve stem extensions, wall supports as well as the valve operator. With all of this inspection information, Benesch prepared a report detailing repair recommendations for the drawdown tower and 24-inch CMP inlet and outlet lines.