EagleHerald/Rick Gebhard
Cement barriers were breached on Bay Shore Road as water washes up on the road Thursday in Oconto.
EagleHerald/Rick Gebhard

Cement barriers were breached on Bay Shore Road as water washes up on the road Thursday in Oconto.

<
1
2
3
>

OCONTO — The Great Lakes has seen some record high water levels in 2019. People of Oconto County was given the opportunity to learn why such flooding has occurred and what to expect in future, Wednesday at a town hall meeting in Oconto.

Representatives from the Army Corp of Engineers (ACOE), the Department of Natural Resources (DNR), Oconto County, the City of Oconto and various towns within the county were present to explain their role in water management, property protection and helping citizens as water levels continue to rise.

Lauren Fry, an expert on hydrolics and hydrology with the AMOE, gave a presentation on the 120 years of recorded Great Lake water levels and what her organization expects in the upcoming months, based on the data it has collected the past decades and even past century.

“Any numbers you hear from the Army Corp of Engineers that are water-level related will be in terms of elevation, using an International Great Lakes Datum using 1985 as a reference point. It references to a point close to the Atlantic Ocean on the Saint Lawrence River. It’s essentially an elevation above sea level,” she explained.

Fry said Lakes Michigan and Huron are closely related to each other and rise and fall as one lake. For this reason, the ACOE refers to those lakes as a single entity: Lake Michigan-Huron.

Water levels are taken daily, but when the official data states what a record water level is, it refers to a month-by-month basis, not yearly, Fry said. So, if the water-level for July breaks a record that just means the water level is higher than it has been compared to every other recorded July.

“There are a few primary drivers of water levels,” she said. “The evaporation from the lake, the precipitation into the lake and the runoff into the lake are all referred to as the ‘net basin of water supply.’ That’s the local supply of water to the lake. That supply plus inflow from the upstream lake all together is referred to as the ‘net total water supply.’ If the net total supply is better than the outflow, then water level goes up.”

Usually the water levels go up and down with each season on a yearly basis. In the spring, snow melts and drains into the lake and it rains more so the water level increases. In the summer the levels go down because the water begins to evaporate more.

However, the water levels have been recorded since 1918 and the overall numbers show a trend of decades with high water and decades of low water.

In 2012-13 the Great Lakes had a record low lake levels. This was the end of a long cycle with record-low levels that began in the 1997-98, Fry said. However, in 2013 and 2014 there was a record two-year rise in water level.

“At that time is when I first started hearing about the polar vortex,” Fry said.  “We had very cold conditions and there are some studies that show evaporation was actually less than in previous years.”

“Now here we are in 2019 and all the lakes, except Lake Michigan-Huron, have set new record high water levels. The previous records were set in the 1980s,” she said. She added that Lake Michigan-Huron was within an inch of setting a new record but ultimately did not set one.

October has been the only month in 2019 that none of the Great Lakes set a record high.

“So what brought us here? Well, to put it simply: It’s been wet,” Fry said. “The past five years have been the wettest five years in the 120- year record for the Great Lakes region.”

The Army Corp of Engineers uses the data it collects to predict a forecast of water levels for the future. Fry said the ACOE predicts that every month next year will have record highs. The forecast issued at the beginning of November is first forecast that has predicted record high water levels for Michigan-Huron, she said.

The reason the ACOE predicts that next year will continue to break water-level records because every Great Lake is at a higher level than it was last year. Fry said because they are beginning at a higher level it will likely continue to get higher once the seasonal water cycle starts for next year.

“We’re starting at higher levels than last year and that sets us up for even higher levels next year,” she said.