History of Lake Scugog

Map of Scugog Pre 1830
Map of Scugog before 1830

History of Lake Scugog

Formation of the lake

The history of Lake Scugog can be traced back to the last ice-age approximately 10,000 years ago.  Ice as much as 1.5 km. thick pushed down from the north scraping and excavating out deep valleys in the soft limestone of the area.  At one point the glacier split into two lobes leaving a deep crevasse which, over thousands of years, received huge blankets of stratified sands, gravel and silt out-wash from the glacier.  This ridge is now called the Oak Ridges Moraine. In some places, even after millennia of erosion, the ridge is over 300 meters in elevation and over 200 meters wide.

This ridge prevented the glacial water runoff from going south to Lake Ontario.  Lake Scugog was formed with this water runoff .  The overflow water left the lake, going north through what is now the Scugog River.  The original lake depth could have been very deep. But it filled in relatively quickly because of the easily-eroded glacial deposits surrounding it.

Arrival of early European settlers

Map of ScugogBy the time the first European settlers and surveyors arrived, Lake Scugog had filled in so that there were just two sluggish channels running north to the Scugog River. There were sections of open water in the deeper areas and in the channels.  The rest was varied wetland with large growths of wild rice, cattails and , deep in the acidic older areas, vast cranberry bogs.  The current “Cartwright Lands” was a huge tamarack swamp beloved by deer.

In the 1830’s, permission was granted to build a grinding mill at Lindsay.  This required a “head” of water so the Scugog River was dammed. The level of the lake increased by ten feet.  This first dam was destroyed and the new dam, built further along the river, brought the lake up to only six feet. Without the dam at Lindsay, there would be no Lake Scugog as we know it now.  History was changed on Lake Scugog and its watershed from then on.

Railway StationThe first years of the new life of the lake were very turbulent times. Many areas of forest, plowed field and even newly built settlers cabins were inundated by the new water level.  This caused years of decomposition and swamp gas within the Scugog basin.  It became a great area for breeding disease-causing mosquitoes.  Malaria made many ill with what they called “ague” at the time.  The native malaria was less vigorous than tropical malaria and did not result in as many deaths but it spread widely in populated, wet areas such as that found in the labour camps for the construction of the Rideau Canal and around the newly-flooded Lake Scugog.  Availability of quinine basically eradicated the disease in Ontario by the 1890’s.

In the meantime, the new depths of Lake Scugog allowed the transport of goods and settlers north and huge quantities of logs and other goods south to the railhead in Port Perry. Scugog’s dense maple, beech, pine and oak forests gave way to the settler’s ax and agriculture became, and still is, the backbone of our economy. However, the cutting of the forests allowed significant erosion and the runoff into the lake began making Lake Scugog, once again, shallower and more nutrient rich.

Beginning of modern times

The 1930’s, 40’s and 50’s saw Lake Scugog as a convenient and pleasant vacation area, with hundreds of small summer cottages in tight, fun-loving summer communities around the lake.  Slowly that changed.  Cottages grew up and became permanent residences.  Then they grew further and became very desirable shoreline communities.   Life on the lake was good!

Eurasian water milfoilSlowly, slowly, however, Lake Scugog aged once again.  The invasive exotic water plant, Eurasian water milfoil exploded on to the scene, peaking in the 1980’s.  This over-abundance of plant life began to recreate some of the conditions that existed after the erection of the dam.  There was too much decomposition which dramatically increased the dissolved plant nutrients which, in turn, stimulated the growth of even more plants and algae.

It is supposed that nature came to the rescue.   The native milfoil weevil, which normally preyed only on the native water milfoil in the lake, found they enjoyed the imported variety much better. The weevil population burgeoned and soon the lake was not perfect but certainly enjoyable as a boater’s and fisherman’s paradise. Crash!  Without the vast beds of Eurasian water milfoil, the weevil numbers sank.

In 2005, 2006, milfoil once again took over, but this time it was a hybrid of Eurasian water milfoil and native water milfoil. This hybrid has stronger, thicker stems and grows in denser stands. Lake Scugog once again had a boating problem, but the fish loved it!

Arrival of the alga Starry Stonewort

Starry Stonewort, a plant-like algae

In approximately 2015, the Stewards’ research revealed a newly-arrived invasive species. Thickly-growing, plant-like string masses seemed to be springing up and pushing everything else out, even Eurasian water milfoil. For a lot more on this new invader see our Research Section and also Invasive Species under Other Projects.

Controlling by chemicals is out of the question.  Cutting is counter-productive and kills many tiny fish as the cut weed is collected.  Keep checking out our blog section under What’s New of this website as well as ‘like’ our Facebook page to see what the Lake Stewards are working on to solve the problem.

Meanwhile, much is being done to protect the lake through the planning process and the engagement of the public, business and agriculture.  The Lake Stewards look forward to knowing the Lake should be healthy for many more years to come. Starry stonewort may be tipping the balance from a weed-filled lake to an algae-filled lake, something none of us would choose. We must continue to try to reduce nutrient input, but also research how it is affecting the lake and what tools we can use to keep the lake healthy.