Deltas form where rivers reach their end point and where there is a relatively calm body of water. When this happens, the sediment particles being carried by the river currents slow down with the water flow and drop to the bottom. This eventually builds up the bottom level. They are hard to form in Lake Superior because the lake is not calm and the particles are carried away. They are common in small inland lakes.
Little Gratiot River Delta, Lac LaBelle
