The Ausable River originates in the moraines around the Village of Staffa. It takes more than 150 miles for the Ausable River to reach its outlet at Port Franks, even though it is only 40 miles from Staffa to Port Franks. During this journey, the Ausable River drains 1142 square kilometres of land and falls 500 feet from its source to its outlet. The Ausable River used to have four major tributaries: Black Creek; Little Ausable River; Nairn Creek; and Parkhill Creek. Parkhill Creek now drains into Lake Huron directly.

The Ausable River once outletted at Grand Bend but years of sediment deposits, by the currents of Lake Huron, plugged the mouth and forced the river to move south to find an outlet. This caused the gradual formation of the ‘Grand Bend.’ At the same time, the Lake Huron shoreline was receding to the west and sand dunes were being created on the shoreline by the prevailing northwest winds. As a result, water became trapped behind the dune ridge and formed an inland lake. This was the birth of Lake Burwell, to the east of the sand ridge. This area is quite shallow and a deep layer of muck was built as the result of plant decay over the following thousands of years. The subsequent partial drainage of Lake Burwell in the late 1800s, created three smaller, shallower inland lakes in this area: Lake Burwell, Lake George and Lake Smith.

The first European settler to the area (1830) was a man by the name of Brewster. He built a sawmill that was powered by the Ausable River and located just south of the “grand bend.” The settlers of the area believed that the dam constructed by Brewster’s Mill caused the flooding in the area. So, The Canada Company tried to get the dam removed but lost the battle in court. In the early 1860s, the local settlers were so unhappy that they burnt down the mill and destroyed the dam. The flooding still continued. In 1868, the mill and dam were rebuilt but by 1878, the dam was abandoned when the mill was converted to steam power. The slideshow below depicts the History of Brewster Mill.

In 1875, The Canada Company constructed a ‘cut’ in the river’s path from the south end of the Thedford Marsh to the Village of Port Franks in order to relieve flooding. This ‘cut’ drained the Thedford Marsh and parts of Lake Burwell and enabled the land to be used for vegetable farming. As a result, the Ausable River empties directly in to Lake Huron at Port Franks. This was the beginning of some problems for the Village of Port Franks. Since the river did not empty into Lake Burwell, or head to Grand Bend, anymore, the ice and sediment that was once dumped in these areas, now emptied into the Cut. This caused ice jamming problems along the Cut as well as in the Village of Port Franks. An interesting note is that the old river bed is two metres/ seven feet higher than the Cut channel. Therefore, the river could not be reconnected in this area very easily.

In the early 1890s the citizens of the Village of Grand Bend decided that they wanted a harbour. So, in 1892, a ‘cut’ was created to outlet Parkhill Creek directly to the Lake at Grand Bend. This ‘cut’ is now deeper (about two metres deeper) than the original river bed and, as a result, the stability of the river bank was decreased (i.e., more bank exposed and overhung due to the increased depth of the channel). This is why Grand Bend has erosion problems along the Cut channel. The creation of this ‘cut’ also resulted in the creation of the Old Ausable River Channel that we know today. Since the channel was blocked at the bend in the river, the flow to the remaining channel was terminated, fed only by precipitation, groundwater, and very little runoff.

In the summer of 1948, floods caused serious erosion problems at the mouth of the river in Port Franks. The Ausable River Conservation Authority was requested to improve the river channel in Port Franks and, in 1952, an extension to the 1875 Cut was undertaken. The diversion channel was now eight kilometres in length. The old mouth was cut off and a new one created but the shifting sands of Lake Huron closed the newly created mouth. The natural river mouth reopened as the result of an ice jam and has remained open in some form since.

Lake Smith was a remnant lake of Lake Burwell (after partial drainage) that existed on our landscape until it was drained in 1955 and converted to farmland for market gardening and cash crops. Before it was drained, Lake Smith covered 400 hectares of land in the Thedford Marsh and was a very important waterfowl area with anywhere from five to 10 thousand ducks on the lake at one time during migration. The lake contained approximately 314 acres of open water and approximately 678 acres of floating bog.

In the early 1960s, a dam was constructed on the Old Ausable River Channel in Pinery Provincial Park. This dam helps maintain water in the old channel.

In 1969, a dam and reservoir were constructed on Parkhill Creek just outside of the town of Parkhill. This dam and reservoir act as a storage area and flood control structure in order to regulate the flow of Parkhill Creek and control the serious flooding and soil erosion problems downstream in the Klondyke area. Parkhill Creek no longer flows in to the Ausable River but outlets itself at Grand Bend through the 1892 Cut.

The Old Ausable River Channel was created due to a series of ‘cuts’ that occurred on the main Ausable River. This channel, from Grand Bend to Port Franks, is fed only by precipitation and small amounts of groundwater and surface runoff. This channel is 14 kilometres (km) in length, 0.5-2.5 metres deep and 20-80 metres wide. There is minimal amount of flow in the spring and virtually no flow by July.

Groundwater recharge in the channel increases as you move southward from Grand Bend. Since there is relatively no flow in the Grand Bend section, there is no flushing of nutrients (whether they are naturally occurring or introduced). The presence of a high level of nutrients creates the right conditions for the excessive growth of aquatic plants and algae.

As was stated before, the water level in Pinery Provincial Park is regulated by a dam and a series of four culverts. This results in differences in water condition upstream and downstream of dam. Upstream of the dam in Pinery Provincial Park, the channel is slow flowing with no outside influences, causing it to be less turbid. Downstream of the dam in the Pinery, there is a back wash effect from the Ausable River Cut.