Prior to European settlement, aboriginal groups inhabited the region around the Ganaraska River watershed, which was primarily a densely wooded area with massive stands of oak and pine trees.
Settlement came to the area after 1663 when the area became a Royal Province of France. French settlers and later British settlers harvested the Oak and Pine trees and settled along the watershed, in particular along tributaries where water powered structures (mills) were erected to harness the water flow.
Research on the Ganaraska watershed was conducted by A.H.Richardson, the Forest Engineer with the Ontario Department of Lands and Forest who wrote 'The Ganaraska Watershed' in 1943, a landmark document in its in-depth research and study of the river system and its development and floods over the past century and a half. It formed the basis for the formation of the Conservation Authorities in Ontario, of which the Ganaraska was one of the first formed. Richardson had been chairman of the inter-departmental committee on conservation and Post-war rehabilitation.
Throughout the years there was seasonal flooding including a few major events. The first recorded flood was in 1813 and it was recorded that the log bridge on Walton Street was washed out. A record taken at the time claimed that this flood changed the course of the river, and disturbed the gravel bed, causing the banks to erode and collapse. This caused the river to narrow with the erosion caused by the flood.
Eight significant floods were recorded between 1876 and 1937. These floods usually were caused by heavy rains but early spring floods were hampered by frozen ground and ice blocking the watershed. On March 21, 1980 the flood of the century hit the Ganaraska River causing significant damage to the town of Port Hope and surrounding area. As a result of this flood, the Port Hope Flood Control Project was undertaken by the Town of Port Hope and the Ganaraska Region Conservation Authority in cooperation with The Province Of Ontario.
Logging requirements
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Go to the posted coordinates and find the sign detailing the history of the Ganaraska Watershed.
1. During the 1980 flood, what was the flow of the river in cubic metres per second?
2. How many acres of downtown Port Hope were flooded?
3. What was the depth of the water in downtown Port Hope in metres?
4. What factors contributed to the 1980 event?
5. Following the 1980 event, channelization of the river through downtown Port Hope was proposed and constructed. The river was widened and deepened over a distance of ____________?
6. Take a measurement of the width of the river at the posted coordinates. This can be done as an estimate or you can walk across the foot bridge located near the posted coordinates and create a waypoint, measuring the distance to the opposite side. What is the width of the river at GZ? Estimate the depth of the river from the top of the bank to the water level?
7. Looking along the river bank, do you see further signs of erosion of the bedrock due to water flow? Is there undercutting along the sides of the river or signs of bedrock collapsing into the river?
8. Optional: Photos are appreciated however no spoiler pictures please.
References: "http://porthopehistory.com/floods/gannyfloods.htm"
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