The drought of 2012 dropped Lake Wawasee’s water level down about 18 inches from normal levels, and even dropped nearby Lake Michigan to its lowest water level in recorded history since 1918. Curiously, however, this water level drop was not seen for all of the more than 100 lakes in Kosciusko County.
Recently, there have been many questions from Wawasee and Syracuse lake residents regarding the lakes’ low water levels. Dr. Nate Bosch, director of Kosciusko Lakes and Streams, a water research center at Grace College in Winona Lake, said there are several factors that influence lake levels.
The first efforts to control lake levels on Wawasee and Syracuse began in 1833 when a grist mill was built to raise the lake level about 5 feet. Then, 1875 marked the beginning of scientific data collection on these lakes, but it wasn’t until 1943 when the data included lake levels.
Several low lake level years were recorded in the 1940s and 1950s, but were not to be seen again until 2012.
Lake Wawasee is unique compared to most other lakes in Kosciusko County, other than maybe Dewart Lake, Bosch said. That’s because it sits near a continental divide, and that it has a relatively small area of land that drains into it, called a watershed.
“This is helpful when we are worried about unwanted dirt and nutrients coming into the lake, which grow algae and weeds,” said Bosch. “But it’s harmful when we want more precipitation and ground water to come from that drainage area into the lake.”
A helpful analogy, according to Bosch, would be a house’s roof and gutter system. “A small roof area (drainage area) would be nice if you want to cut down on the amount of leaves and twigs that clog your gutters and downspouts,” said Bosch. “But, if the goal was to get lots of water through gutters from the roof, there would be a small disadvantage with that small roof.”
Lake Wawasee’s small drainage area is helpful in keeping it cleaner than most years, but in drought years it exacerbates the dry weather and makes the lake more sensitive to lower water levels.
The only influences on the water level that can be changed are irrigation usage around the lake and in the lake’s surrounding drainage area, as well as how the lake level control structure is operated throughout the year, added Bosch.
So, what made 2012 special and what caused these very low lake levels? Several factors converged, Bosch noted. Warmer than average temperatures led to more evaporation during the summer and the previous winter; normally, ice cover would stop evaporation during winter.
Also, said Bosch, lack of precipitation dried up three of the four in-flowing streams, and soils were so dry they soaked up the little precipitation that did fall.
Bosch said a lower local water table likely caused groundwater springs in lakes to reverse flow and become drains out of the lakes. Increased irrigation usage additionally led to more evaporation losses.
Wawasee and Syracuse lakes have unique characteristics that increase their potential to be susceptible to low lake levels. These characteristics include a relatively small watershed compared to lake size, a complex geology with strong connections to groundwater, and a lake level control structure, which purposefully lowers levels in the winter.
For more in-depth coverage of this topic, see this week’s issue of The Mail-Journal.