Sunday Feb. 7, 2016

The Lake Ontario shoreline is constantly changing due to the effects of erosion and this can be seen in full measure at the Cathedral Bluffs in Scarborough.  We previously looked briefly at the formation of the Scarborough Bluffs in Sand Castles with a post going west from Bluffer’s Park.  Today we go east from there toward the Cathedral Bluffs and will see the effects of erosion in several forms.

The cover photo above shows a small section of the bluffs where several homes sit above a horseshoe shaped section of the bluffs that has collapsed in several places.  Sloping sand piles, or talus, can be seen in half a dozen spots reaching nearly to the top of the bluffs. In some places homes at the top have been losing about 30 cm of their back yard per year and the Toronto Regional Conservation Authority has been implementing measures to reduce this and preserve the bluffs.  The section of sand pictured below provides home to a large number of bank swallows who live in a relatively narrow band dictated by the density of the sand in the section.  The bluffs provide home to many birds and butterflies as well as white tail deer and coyotes.  They also serve as a green migratory route for wildlife that is moving between the various ravines in the area.

As you walk along the Bluffer’s Park Marina an interesting attempt to overcome erosion can be seen on the top of the bluffs.  Someone has built shoring for the edge of their property.  Normally if you want to shore up a structure you transfer the weight onto something solid.  That isn’t possible here because the sand is up to 96 metres deep. Although erosion has been slowed down through the implementation of shoreline controls it continues in spite of mankind’s best attempts to control nature.  This piece of property will eventually disappear and perhaps so will the next one north of it.

Several actions are being taken to help reduce the rate of erosion on the bluffs.  Gentle slopes are being developed rather than the vertical surfaces.  The picture below shows shrubs, reeds and grasses that are growing along the base of the cliffs.  The common reed grows in wetlands and is considered an invasive species but it is encouraged here because of it’s root system which is serving to hold the sand together and reduce the amount that gets washed away.  The fact that it’s yellowish stocks are growing half way up the side of the bluffs shows how much water is retained in the sand.

The bluff in the picture above looks quite different when viewed from the side.  Another strip of bird nest holes runs along the same layer of sediment in the bluff and can be seen at the front corner of the nearest point in the picture below.

Between the sections of bluff there are several ravines that have been cut through the sand.  Invariably there is a rivulet of water running in the bottom and it is always clouded with sand.  This swells when there is a rain storm.  On the right hand side of the picture below is an outcrop of sand which is being held together by the roots of the shrub growing on top.

A shingle beach is one made up of stones ranging in size from 2 milimetres up to around 200.  Quite often they occur naturally and serve to protect the beach from the erosive effects of the waves in a process known as armoring.  When the stones are placed intentionally they are called riprap and often include pieces of concrete and brick from demolished buildings.  To control erosion much of Toronto and the surrounding areas have been given hard shorelines through riprap and concrete forms.  Along this beach there are stretches of riprap made up of rounded stones that have been deposited as a buffer between the waves and the reeds on the edge of the bluffs.

Among the stones on the beach is this concrete block which has been eroded down through abrasion.  The repeated effect of the smaller stones knocking against the sharp corners of the block has worn them off.  The waves only reach this far up the beach when there is a storm and the waves are at their most powerful.

Past the shingle beach is a stretch where the reeds have reached almost to the water’s edge.  A recent collapse of the side of a higher range of bluffs has closed the beach at this point.  The waves will carry this away as the lake continues it’s relentless assault on the shoreline.  The sandy beaches that line the shore of the lake west of the bluffs are made of material which has been deposited from here.  The predominating current of the lake is known as longshore drift and on the north side of Lake Ontario it is in an westerly direction.  Water entering the lake from Lake Erie through the Niagara River carries the lake water east along the southern shore toward the St. Lawrence River.  This creates a motion in the lake that carries sand from the bluffs to the west and deposits it to form a series of ten beaches.  These range from Bluffer’s Park beach in the east to Sunnyside and Marie Curtis in the west. Notice the white birch tree that is hanging over the edge of the bluff just beyond this mudslide in this photo.  It will find itself in the lake shortly.

Behind me the roots of one of the dogwoods rise out of the water.  It’s journey from cliff top to water front has been completed.

The picture below shows one of the places where the water in the bluffs is draining across the beach and carrying fresh sand from recent collapses into the lake.  The beach is protecting the bluffs from the action of the waves and gentle slopes reach up to the bluffs. In spite of this, the sand continues to relentlessly erode away.  A $6.5 million dollar investment east of here has been made in the interest of protecting homes that are falling over the edge of the cliff but one must wonder how effective it will be in the long run.

Looking toward Lake Ontario the lighter sands of the bluffs are carried into the waves. The lake will carry this sand until it deposits it along the Leslie Spit, now that the spit guards the Toronto Islands from the east.  The Toronto Islands were a peninsula guarding the harbour in 1793 when York was founded.

The Scarborough Bluffs extend east from here and include a ravine that was formerly known as the Grand Canyon of Scarborough, before it was partly filled in.  Perhaps we’ll get a chance to investigate there soon.

Google maps link: Cathedral Bluffs

Like us at http://www.facebook.com/hikingthegta

Sunday Jan. 17, 2016

Glacial Lake Iroquois covered downtown Toronto with about 60 metres of water which would have covered all but the dome of the Rogers Centre and left it sticking out of the lake some four kilometres from the shore.  The lake had been left behind when the last great North American glacier retreated.  Lake Iroquois cut a prominent bluff along it’s shore which can still be traced through the area today.  The lake suddenly drained through the Hudson River about 12, 200 years ago when the weight of ice in northern Ontario and Quebec caused the crust to tilt.  The lake drained to a much smaller size called Lake Admiralty whose shore line was about 5 kilometres south of Toronto in an area known locally as the Toronto Scarps.  Since then water levels have been rising due to post glacial rebound as the tilt is slowly reversed. The former shoreline of lake Iroquois has become an escarpment known as the Iroquois Shoreline.  Casa Loma overlooks the city from the top of this escarpment.  The Scarborough Bluffs are also part of the ancient Lake Iroquois shoreline.  A 1912 picture of the bluffs from the Toronto archives is presented below.

The Scarborough Bluffs had been eroding at a pace of a metre per year until recent erosion controls have slowed the pace.  The sand that has been falling into Lake Ontario is carried by the westward rotation of the lake and deposited near the harbour in Toronto. Over the centuries this deposit has formed Toronto Islands.  When Elizabeth Simcoe came with her husband to found the town of York (Toronto) in 1793 she took an active interest in the land around her.  Her journal provides key insights into the founding of the town and pioneer life in it.  She hiked up and down the Don River as well as around the islands.  She fell in love with an area east of the city that reminded her of home.  Along with her husband, Lieutenant Governor John Graves Simcoe, she contemplated building a summer home on top of the bluffs and calling it Scarborough.  From this we get the name of the township and the city that grew there.  The picture below shows some of the bluffs in Bluffer’s Park where I parked.  Brimley Avenue is one of the few places where one can drive down the bluffs to the beach level.

The cliffs at Scarborough, North Yorkshire in England are made of limestone and not sand like the ones near York.  However, the local ones reminded Elizabeth of the cliffs near her home and so she named them the Scarborough Bluffs.  The picture below is taken from worldtravelguide.net and shows the remains of the 12th century Scarborough Castle on top of the cliffs in England.  These cliffs have changed relatively little since Elizabeth viewed them in the 1790’s.

The sand formation of the Scarborough Bluffs occurred when the area was the bottom of a large river delta.  The first 46 metres (150 feet) contain the fossils of plants and animals while the upper 51 metres (200 feet) is a mix of boulder clay and sand that was left during the retreat of the last ice age.  The Rogers Centre would rise to about the same height as the bluffs if it was built beside them.  The bluffs run for a distance of about 15 kilometres east from Victoria Park Avenue to the mouth of Highland Creek.

A thousand years ago the bluffs were a full kilometre farther out into the lake.  In the 1950’s and 1960’s it was fashionable to build homes on top of the bluffs overlooking the lake.  This destabilized the sand below and sped up erosion.  Many of these cottages have already had the ground disappear from below them.  To slow erosion the city has built hard shorelines with large chunks of rock along portions of the bluffs.  Even with these controls in place the piles of sand are under constant attack from wind, rain and ice.  The various shapes of sand that are pictured here will certainly be different a year from now.  The picture below shows the cracks that appear in the sand and where new sections can collapse at any time.

A storm was brewing out over the lake but it was a nice enough day along the bluffs and several people were here taking pictures.  Some were climbing the bluffs which speeds up erosion and ends up with an ever growing list of people who get trapped and need to be rescued.  If this happens to you, expect to get an expensive bill in the mail.

This part of the bluffs has eroded with an open core down the middle.

I walked along the edge of the bluffs where the sand has collapsed into fresh piles of talus. Some appeared to have come down since the last good rain.  They say that if you listen closely to the bluffs you can hear the sand shifting inside.  Looking down the bluff face there is a large corrugated storm pipe sticking out.  This is set in a ravine that can’t be seen from this angle but the length of pipe sticking out is an indication of the amount of erosion that has taken place since it was laid.  The pipe itself has corroded and icicles hang from a large hole about 2 metres from the end.

Bluffer’s Park, including the upper meadow, is a great place for bird watching.  In season the meadow is also home to many species of butterflies.  The cardinal in the picture below provided a bright red splash of colour in the trees near the ponds.

Storm water collects on all the paved surfaces in the city and runs along roadways picking up contaminants. These are carried into the storm drains and eventually out into the the lake. Toronto has implemented a Dunker’s Flow system in Bluffer’s Park. The picture below shows where the storm water is released at the bottom of the bluffs after being collected up top.

Karl Dunkers, of Sweden, invented a system for storm water purification.  Storm water is released into the first of five cells where it begins to have impurities filtered out.  The picture below shows the settling ponds and the walkways in between some of them.  Each walkway has a screen suspended below it that causes solids to drop out of the water before it passes into the next cell.  The final cell is a naturalized wetland where marsh grasses provide a living filter before the water enters the lake.  When the sediment in the filtration cells reaches a certain level it is removed.

Two small peninsulas have been created to provide protection for the bluffs and to give vantage points for people to enjoy the view.  This picture is taken from the closer of the two.

One of the unique features of the Bluffer’s Park facilities is the shape of the buildings themselves.  Built in 1973 they fit in nicely with the shapes of the eroding bluffs behind them.

Google maps link:

https://www.google.ca/maps/@43.7080024,-79.2341376,15z

Like us at http://www.facebook.com/hikingthegta

Saturday Jan. 16, 2016

The Spencer Creek reach between Bullock’s Corners and Crooks’ Hollow is one of the best dammed stretches of water we have investigated so far.  Beginning with the old dam foundations of William Bullock’s grist and saw mills and continuing upstream to the Christie Dam we found the remains of at least ten of these old structures.  One might expect that the earliest industrial park in Upper Canada would be in York (Toronto), Bytown (Ottawa) or Kingston (first capital of the Province of Canada, 1841) but it was in fact at Crooks’ Hollow near Hamilton.  We started our hike in Bullock’s Corners where at this time of year about the only place you can park is at the park on Park Street.

Bullock’s Corners centres around the site of a large grist and saw mill built in 1841 by William Bullock.  The mills continued to operate until 1866 when they were converted to a blanket factory.  A three story stone building was erected after the original one was destroyed by fire and it continued under various owners until damaged by a flood in 1938. The remnants of the dam mark the site.  Adjacent to it was the mercantile block William built in the 1840’s.  It consisted of general, flour and feed stores as well as shoe and harness maker’s shops with some apartments above.  The foundations of a former storage shed are shown below.

John Green Came to Spencer Creek in 1797 and built a mill, establishing the town name for Greensville.  Bullock’s Corners and Greensville are separated by Spencer Creek and in the early days by language as well.  Bullock’s Corners was home to the mill owners and was an English speaking town.  Greensville was home to many of the mill workers who spoke predominantly French.  Green’s mills were later sold to Andrew Todd Kirby. Although Crooks’ Hollow originally only encompassed the small area around James Crooks’ mills upstream, the term has now been applied to all the industrial operations as far down stream as the Kirby dam.  The picture below shows a more recent Kirby dam, made of concrete, with square stop logs still in the creek bed.

In addition to about 2200 dams in Ontario there are the remains of countless former dams. Along Spencer Creek you can find the remains of several construction methods that were employed over the years.  The earliest dams were made of wood cribs filled with rubble. Due to the high maintenance requirements, and the dangers presented by them, these were often replaced with large field stone dams.  After 1900 concrete became the standard for dam construction.  The Cockburn Property was taken over by the town of Dundas in 1909 and contains the remains of the old stone dam from his sawmill.  Along this stretch are the more complete remains of another modern concrete dam and mill.  This dam includes the mill foundations in the foreground, just behind that is the rectangular turbine housing and then the slope of the spillway.  The earthen berm on the far bank of the creek once extended to the side of the spillway.

The Crooks’ Hollow Dam was built in 1913 to create a reservoir for the provision of water to the town of Dundas.  It was 5 metres tall and 30 metres wide with 4 spillways consisting of three overflow weirs and one stop log bay.  The picture below from wikipedia shows the dam in 2010 when all four spillways were in action.  The dam was assessed for safety concerns in 2007 and it was determined that the concrete had deteriorated to the point where it was becoming a potential danger during times of high flooding.  Even the concrete repairs that can be seen on the first spillway below were determined to be unsafe.

It was decided that the dam needed too many repairs to be practical and it was recommended that it be removed.  Restoring the creek to it’s former level would provide additional benefits in water quality and wildlife habitats.  The dam was demolished in 2013 and the remaining abutments were turned into viewing platforms.

Water was drawn from the bottom of Crook’s Hollow reservoir and taken by pipe to the town of Dundas to provide for the needs of the community.  After town water became available in Dundas the reservoir was used by a golf course for irrigation purposes.  The cast iron pipe that once carried drinking water still runs along the side of Spencer Creek. It is now broken in several places and trees are growing on top of it.  The picture below was taken near the Kirby Dam and there is a small waterfall known as the Greensville cascade which descends the hillside in this same location.

Just upstream from the Crooks’ Hollow dam are the remains of a much earlier stone dam known as the Morden Dam.  This little cascade waterfall was hidden for 100 years below the Crooks’ Hollow reservoir but is revealed now that the dam is gone.

James Crooks was born in Scotland in 1778 and came to Upper Canada when he was 13. He served in the war of 1812 where he fought in the Battle of Queenston Heights in which General Issac Brock perished.  In 1814 he moved to a 400 acre lot on Spencer Creek which he had purchased in 1811.  Here he set up the first major industrial complex in Upper Canada.  His milling empire consisted of a grist mill, a tannery, distillery and a linseed oil company.  In 1826 the British Government imposed a heavy tariff on paper imported from the United States.  A 500 pound reward was offered for the first successful paper mill in the colony. With the help of the Barber family James Crooks won that prize for the paper mill he built just downstream from the grist mill.  The Barbers later moved to Georgetown and built the Barber Paper Mills and the Barber Dynamo.  The map below shows Crooks’ Hollow as it existed in the late 1820’s.

The Darnley Grist mill was completed in 1813 by Crooks and was named after Lord Darnley of Scotland who was a famous ancestor of Crooks.  The mill was made of stone quarried downstream near Morden’s mill.  It originally had a 9 metre overshot waterwheel that supplied power to the four run of stones inside.  It’s first mission was providing flour for the British army during the war of 1812.  In 1860 when Crooks died the mill was sold and converted into another paper mill.  In the 1930’s the Greensville Paper Company replaced the wood floors with poured concrete.  The mill was later abandoned in 1943 after it was destroyed by a fire.  The picture below shows a couple of remaining window frames inside the mill.  The cover photo also features an internal view of the old paper mill.

The Darnley Cascade is a 4 metre high waterfall just upstream from the mill site.

The Christie Conservation Area Dam is 180 metres long and was completed in October 1971.  It features two sluice gates and 8 spillways that flood an area the size of 900 Olympic size swimming pools.  It is designed to provide flood control for areas downstream including Webster’s Falls and the town of Dundas.  This picture is taken from the top of the Christie dam looking down on Spencer Creek, which is full of ducks.  The picture also shows the steel structure from a previous dam.

There are several dams and lots of foundations that space didn’t allow us to present here but which are worth the exploration as well.

GPS coordinates for the paper mill: 43.27648N 80.00685W

Google maps link:

https://www.google.ca/maps/@43.2770014,-80.0015295,16z

Like us at http://www.facebook.com/hikingthegta