The
Ausable River originates in the moraines around the Village of Staffa. It
takes over 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 km2 of land and falls 500 ft. from its source to its outlet. The Ausable River used to have 4 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 NW 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
1800's, created three smaller, shallower inland lakes in this area:
Lake Burwell, Lake George and Lake Smith.
The first 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.
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 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 2metres/ 7
feet higher than the cut channel. Therefore, the river could not be reconnected in this area
very easily.
In the early 1890's 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 (~2m 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 8 km 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 5 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 1960's, a dam was constructed on the Old Ausable River
Channel in the 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 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 the Pinery 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 the Pinery, 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”. |
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