Age of Lakes

Bodies of water, like all living things, go through an aging process. In lakes, this aging process is known as “eutrophication,” it means aging.

Young lakes are called “Oligotrophic.” Traits of young lakes are:

Over several thousands of years, shorelines of oligotrophic lakes erode and become less steep. The rocks on the lake bottom grind against each other creating sand, while more plant life emerges on the shore and in the water. The lake reaches middle age.

Middle-aged lakes are called “Mesotrophic.” Traits include:

After several thousand more years, mesotrophic lakes gain nutrients from the fallen, decayed leaves from deciduous trees, decayed shoreline plants, decaying aquatic plants, and the remains of fish and other water creatures. The lake bottom near the shore becomes covered with silt and sediment. The lake has become an old lake.

Old lakes are called “Eutrophic.” Traits include:

It is the nature of all lakes to fill themselves in and become land. After several thousand more years, your lake will continue become shallower in the center, more shoreline will erode into the water, trees will fall in, leaves, dust and dirt will blow in, weeds will become thicker and grow out farther into the lake, die, decay and add to the bottom.

We have several names for bodies that were once lakes. They’re called bogs, swamps, wetlands and finally, “darn good farmland!” You won’t have to worry about this in your lifetime though. A very rough rule of thumb is a lake will fill in about two feet every thousand years. So if your lake is only 20 feet deep, it will be (on average) about 10,000 years before it’s filled in completely. Until then, enjoy it!