This is Roald Tweet on Rock Island.
Now and then, most of us get the urge to help Mother Nature out. Wait. Before you lift a finger, you might want to check with the Corps of Engineers up around La Crosse, Wisconsin.
In 1938, as the engineers were building Lock and Dam Number 6 as Dresbach, Minnesota, toward the end of the immense 9-foot channel project on the Upper Mississippi, they saw an opportunity to give Mother Nature a hand. Between Dresbach and La Crosse lay a network of small farms, dense woods, fields and swamp that could easily be dammed to form a beautiful lake.
Lock and Dam did just that, and the result was Lake Onalaska, which grew into a lush, fertile haven for water plants, fish, waterfowl. Lake Onalaska became a prime example of the web of nature, a delicate ecological balance where every species counted.
Soon, however, the water plants, upon which the fish depended for food and oxygen, became so thick a motorboat couldn't operate. There were complaints. The Corps had to do something.
Then in the late 1980s, prolonged drought caused the lake to stagnate, depleting the oxygen supply. Too many motorboats stirred up bottom sediment and helped kill off most of the plants.
So, in 1989, the Corps began several habitat rehabilitation projects in Lake Onalaska. They dredged sand from the lake bottom and build islands in the middle of the lake. which they covered with topsoil and seeded to stabilize them.
Gradually, the plants and oxygen returned. Today the lake is on its way back to health. Too much health, unfortunately. Increased fish populations brought hundreds of cormorants to the lake to fish, competing with humans. Cormorant droppings have already killed all the vegetation on one of the islands in the lake.
Recently, there may be even more trouble. The tundra swan population is increasing, wreaking havoc with the water plants migrating ducks and geese need to provide them with enough energy to migrate.
By now, I'm sure the Corps of Engineers realizes that once you fool with Mother Nature, it's almost impossible to stop tinkering.
Rock Island Lines is underwritten by the Illinois Arts Council, a state agency, and Augustana College, Rock Island.
