A year after the end of the Lake Weyauwega drawdown, the Wisconsin Department of Natural Resources is seeing more depth in parts of the lake.
“The upper end, where the Waupaca River comes in, we gained about two feet of depth,” said Ted Johnson, a water resource specialist in the DNR’s Oshkosh office.
The drawdown of Lake Weyauwega began on June 17, 2011, and ended in April 2013.
When the lake was drained, plants that normally would not grow there in water appeared.
After the water level was brought back up a year ago, Johnson said area residents were concerned about the vegetation they saw in the lake, such as the aquatic flowering rush.
“I’m cautiously optimistic that a lot of it has dried back up because it was too deep of water for it to survive,” he said.
Before the drawdown began, the DNR worked with members of Lake Weyauwega Restoration to shoot the depth of the lake.
In mid-January, they did so again to see what the lake’s depth looked like after the drawdown was complete.
The increase in depth seen in parts of the lake is consistent with what the DNR has seen after other drawdowns of lakes, Johnson said.
“This is the best we’ve seen,” he said.
Johnson said that before the drawdown, the lakebed was mainly comprised of a thick, organic material.
During the drawdown, that material decomposed.
“As a result, the lake gained about two feet on the upper or west end,” he said. “We shot about 80 or 90 different points (in January). We did half on the west end and then half on the east end. The east end averaged just under a foot (in increased depth).
When asked why the lake did not gain as much depth there, Johnson explained that because the dam was still backing up some water, while the drawdown was under way, there was not as much decomposition of the organic material in that part of the lake.
He said the DNR will continue to monitor the lake.
“We will be doing a plant survey in July or August on the lake,” Johnson said. “I think it’s going to look a lot different this year than last year.”
The fish population will also continue to be monitored.
Al Niebur, a senior fisheries biologist in the DNR’s Shawano office, said a fish survey was conducted on May 13.
“I established two 0.5 mile stations that we are going to replicate every spring and fall to monitor fish populations over the next two to three years, he said.
Last week, the DNR sampled Northern Pike, Largemouth Bass, Smallmouth Bass, Bluegill, Pumpkinseed, White Sucker and Shorthead Redhorse, he said.
“All species were relatively low in number. Yearling size Northern Pike dominated our catch and were likely the result of a large fingerling stocking the DNR planted last summer,” Niebur said.
He said adult fish were present for all species.
He hopes those adult fish provide suitable spawning stock to restore fish populations through natural reproduction.
Niebur said the “DNR also plans to continue (the) stocking of fingerling Northern Pike and Largemouth Bass over the next two to three years to augment populations during recovery.”