By Ricky Rieckert
Dear readers,
Hopefully everyone is doing well.
This week, I want to touch on the subject of dam removal, along the Fox River.
There are groups supporting removal of nine dams, from Carpentersville to Montgomery on the ”Mighty“ Fox River.
Then there are groups of individuals against removing the dams, including myself.
Let’s start from the end of the Ice Age, where glaciers broke loose, creating rivers, lakes, and seas.
The Fox River is largely from the work of glaciers over the past 100,000 years. Above and throughout the rolling valleys of limestone bedrock underlying The Fox River Valley is a mix of soils bulldozed from Wisconsin, by glacial ice and melt waters.
The material left behind is known as glacial till. Light materials, silts and clays, were swept downstream and out of the water shed.
Heavier materials became the river bottom in the bedrock crevices, often sorted into lenses of sand, gravel, and rock.
This glacial cycle repeated itself at least three times over the past 100,000 years, giving the Fox River its natural sand and rock bottom.
The Fox River pathway south from Wisconsin, is defined by two principal moraines of till left by the great Wisconsin glaciation that ran parallel to the Lake Michigan shoreline.
The Marengo Moraine became the western boundary of the Fox watershed, about 25,000 years ago.
The Valparaiso Moraine, the eastern boundary, was left when the last glacier melted 10,000 years ago.
To better appreciate the uniqueness of the Fox River and its valley, hosting 153 State-threatened or endangered species, you need to go back nearly 450 million years, when the Fox River Valley was beneath a warm shallow sea.
For tens of millions of years, great coral reefs grew at the bottom of that sea. The ocean floor rose and became land.
The land split, forming the great continents with the Atlantic Ocean in between. With aging and pressure over those hundreds of millions years, the calcium-rich corals would compress to become the thick calcium-rich limestone bedrock that today underlies the Fox River Valley and its tributaries.
On an average day at its midpoint, the Fox River will carry away in its waters, more than one million pounds of dissolved limestone rock, giving the Fox a hardwater chemistry that has provided nutrition to a large and diverse population of the Valley’s inhabitants.
That included the calcium needed to build the shells of the Fox’s once abundant native mussel communities and the calcium needed by its cows to produce milk in quantities that made Elgin the largest milk town in the Midwest, between 1880 and 1910.
With its ancient underlying limestone base, as well as its confinement between two north/south-oriented glacial moraines, this young river offers a unique character to be explored and treasured.
More on the Fox River next time. Have a nice week.