There was a time when the Ausable River did flow naturally into Lake Huron at Grand Bend. Later, due to the natural northwesterly winds in the area, sand dunes developed naturally in the area. As a result and due to the hairpin turn this location came to be known as 'Grand Bend', the name Grand Bend was given to this location on Lake Huron due to the fact that the original water flow from the Ausable River literally made a 'grand bend' here and continued to flow generally southward to the current location of Port Franks.

At the same time the Lake Huron shoreline was receding to the west and sand dunes were developed on the shoreline to the west due to the prevailing northwest winds. As a result water became trapped behind the dune ridge and formed an inland lake to the east of the dune ridge which became known as Lake Burwell. This area was quite shallow and a deep layer of muck was built as the result of plant decay over several thousand years. Subsequently the partial drainage of Lake Burwell in the late 1800's created three smaller, shallower lakes from the original lake; the lakes became known as Lake Burwell, Lake Smith and Lake George.

A man by the name of Brewster was the first settler in the area in 1830. He built a sawmill south of the 'grand bend'. Settlers in the area blamed the the mill for the flooding of the area. The Canada Company tried to have the mill removed but were unsuccessful. The Old Ausable is, for the most part, a shallow stream. There is only one small dam on this watercourse between Grand Bend and the Ausable River at Port Franks which helps to maintain the water level which for the most part is not much deeper than a couple of feet except where this stream enters the Ausable River near Port Franks. Culverts at different elevations along the length of the watercourse between Grand Bend and Port Franks aid in maintaining the water level in the Old Ausable Cut. There are no water courses flowing into this body of water, only run-off from snow melt and rain fall.