During the spring/summer 2015 northern Indiana flood event, the Markle Dam, Markle, Indiana, was near “fully loaded” for a record 33 days. Fully loaded means the dam had high water against it (high pool), hydrologic loading, or pressure—so much that it was near its engineered design maximum for this extended timeframe. The duration of the dam holding water was approximately three times longer than any previous high pool event.
When the waters abated and Markle residents set their umbrellas to dry, they had time to reflect on what that really meant and wonder about the future.
Markle Dam is part of the J.E. Roush Lake flood risk management project, and it protects the majority of the town’s center. For most of the year, Markle Dam holds back no water at all. As the lake’s pool rises during flood events, however, Markle Dam keeps the waters from inundating the part of the original river channel where the town is located in somewhat of a bowl. This configuration essentially creates an oxbow, and during normal conditions, small inlet and outlet structures allow some water to flow through the town and the original Wabash River channel.
During the heavy rains, the Corps dam safety team and Roush Lake personnel kept track of some minor seepage around the ends of the earthen dam. Roush Lake Manager Tony Schoenecker’s duties were to maintain 24-hour operational control of the dam, its releases, the Markle pump station and the levee at Star of Hope Cemetery during the high water event. In addition, lake staff did dam safety inspections and read the dam instrumentation.
The situation was critical. Cometh forth the dam safety experts to Roush Lake and Markle. Nathan Bryan, Alex Hamilton, Chun-yi Kuo, Steven Shifflet, A.J. Fleming, Robby Wheeler, Jacob Neinaber, Cody Sunderhaus, Ross Wright and Duane Pfouts formed two-person teams for 24-hour surveillance, reviewed the instrumentation and inspected critical areas during the high pool loading.
“There was so much going on during that time period. It was an interesting symphony of people doing a great job so the work goes as well as it can,” said Schoenecker.
The dam safety staff and the operations (lake) staff worked closely together during these events. Scot Dahms, Upper Wabash area project manager, established two-person second-shift and three-person first-shift teams, enabling project staff to cover the 24-hour rotations that became necessary during the prolonged high-water event. Teams that focused on Markle Dam included staff from Roush, Salamonie, and Mississinewa lakes. Donald Unger, Garth Stout, and Jared Perrott from Roush Lake were joined by Daniel Unger and Alex Selig from Salamonie Lake, and Grady Stout from Mississinewa Lake. As the high water conditions persisted—more than 19 inches of rain fell in a 33-day period—even Nolin River Lake in Kentucky answered the call sending Aaron Sullivan to assist. Together, the teams ensured all bases were covered at the Markle Dam, as well as the main dam in Huntington Township, and the levee at the Star of Hope Cemetery in Rock Creek Township.
With more activity and surveillance around Markle Dam, the public inquired about the integrity of the dam, seepage and public safety: “Were there issues with the Markle Dam? Did it need to be fixed?” Questions and unease lingered, even after the waters receded.
At the request of Markle Town Council President Jeff Humbarger, in mid-September, Jeff Esterle, Louisville District dam safety program manager, and Bob Anderson, district dam safety emergency action plan coordinator, accompanied Roush Lake operations staff, Schoenecker, Unger, and Stout, to the Markle town council meeting to discuss the dam conditions and seepage.
The seepage turned out not to be a big concern. “The dam performed very well during the flood event,” said Esterle, “and no follow up activities are necessary beyond continuing the USACE routine surveillance and monitoring program.”
Several questions from the wastewater treatment plant manager came up at the meeting about the Markle Pump Plant’s capacity having been exceeded for several hours during one night of heavy rain. During that brief episode, the water level in the town continued rising despite the pumps removing their designed maximum output of 43,500 gallons per minute. Some discussion occurred on possible ways to eliminate this rare kind of circumstance. The treatment plant manager appreciated the Corps’ feedback, concluding that as long as the pumps and back-up generators in the event of a power failure worked, there were no major issues.
Esterle explained that the increase in activity at the dam was more due to the duration of the event rather than the condition of the dam. The increased loading time at a high level increased the need for close monitoring. “When dams are loaded to historic levels and durations, we want to closely monitor their performance,” he said.
Markle Dam did see an increase in seepage amounts, but it was in areas observed during previous events, and the seepage was not carrying soil particles. “That would be a mechanism referred to as ‘internal erosion’ and would be a distress indicator. No distress indicators were observed during our efforts.”
After the meeting, the local newspaper quoted Humbarger saying that he feels the dam is safe and operating properly.
“When there are questions concerning the integrity of one of our projects, we feel it is important to address the public’s concerns,” Esterle said. “This is even more important with a project like Markle Dam where the project is in such close proximity to residents, and its operation has a noticeable impact to the community annually.”