Cultural Landmarks of Hamilton-Wentworth

Beverly Swamp

Location:  25 kilometers north-west of Hamilton, in Flamborough, Ontario

Beverly Swamp is at an elevation of 265 to 270 meters above sea level and covers approximately 20 square kilometers. The Hamilton region is drained by several rivers and creeks which include Spencer Creek. These rivers and creeks are regulated not only to control floods, but to create recreational areas for local residents. The swamp also plays a role in water regulation within the river and creek system. Beverly Swamp is a large swamp that is connected to Spencer Creek. It offers an excellent habitat for waterfowl, fish, deer and other animals. Since the swamp attracts a multitude of animals, it is also excellent for bird watching and fishing.

The swamp is made up of layers, which include peat on the surface and then, marl, sand, clay, silt, gravel, and dolomite rock bed which occupy two distinct depressions in the rock bed. The swamp was created by the existence of the impermeable marl layer which is approximately 1/2 meter thick with approximately one meter of peat moss above it. The marl restricts the flow of water and traps it in the peat layer. Thus, most of the hydrological or water activity occurs in the peat layer and it is a natural water storage area for Spencer Creek. Water is accumulated by the peat through ground water, rain, and snow which melts primarily in March. Any water loss is usually due to evaporation and outflows. Annual precipitation in the swamp is approximately 840 mm, while the annual mean outflow is approximately 460 mm. Even though the peat has an excellent capacity for water storage, it may be unable to absorb any more water in times of great water inflows. Once the peat is unable to absorb any more water, its water table level will increase, which is already close to ground level since it is trapped by the marl. When this occurs, the swamp will flood and large outflows may be reported.

Every year there is a protracted period of time in which the soil of the swamp supports the growth of water subsisting plants. The entire area is covered with thick vegetation and the prominent trees of the Beverly Swamp include white cedar, red maple, birch and aspen.

The swamp has also had to adjust to human intervention. In the early part of the nineteenth century, large peat moss excavations were conducted which left several large depressions. These depressions resulted in ponds, since the peat was no longer there to regulate the water table. In the 1960's, a gravel road was built which divided the swamp into two halves. This prevented the easy flow of water within the swamp from the north portion to the swamp outlet. Further interventions included the 1974 Hamilton Regional Conservation Authority's dredging of the swamp. This was done to create a recreational fishing area. Once the dredging was completed, the sediment was pumped out and released into Spencer Creek. In November of 1974, the sediment levels in the creek rose from a normal 10 parts per million (PPM) to 103 PPM. However, the swamp and creek recovered and no lasting negative effects were observed.

One of the largest interventions occurred in 1982 with the installation of fifteen, 500 kilovolt transmission line towers.  These towers would connect the Nanticoke generating station to the Pickering generating station to increase the power supply to southern Ontario.  In order to accommodate the towers, an 860 foot wide corridor was to be cleared through the swamp.  However, when 133 acres of the swamp were sold by the Conservation Authority for $32,000, it made certain stipulations before it would agree to the sale.  First, the corridor would be reduced to 610 feet wide, the roads created would have to be removed upon the Conservation Authority's request, and the clearing of the swamp would have to be kept to a minimum. 

Once Ontario Hydro agreed to these terms, construction of the towers began.  Each tower had four stabilizers which were anchored directly to the dolomite bedrock. In order to complete this project, forest area had to be cleared which allowed more water to reach the ground placing a strain on the peat to regulate water flows. Moreover, the clearing of trees changes the temperature resulting in differential heating between the forest and clearings, producing more rapid spring melts.

Test drilling and the final installation of the towers punctured the marl and damaged the peat structure, This resulted in an increase in pH levels and an increase in the hardness of the water. As well, it created uneven levels in water table elevations. The cost of the project escalated as the estimated depth of the rock bed was not the reported 12 feet, but actually 51 feet in some areas.  This fact increased the cost of the project from $1.5 million to $2.2 million.  Since the project was carefully planned, the swamp experienced only localized trauma. Thus, the swamp was able to adjust and recover from these changes.

Over the past two centuries, there has been an encroachment by rural developers into swamp areas. In fact, 80% of southern Ontario wetlands have been destroyed which create an imbalance in the natural movement of water. The natural hydrological environments need to be preserved not only as a habitat for hundreds of plant and animal species, but for the natural balance and distribution of water within the region.

References:
Woo, Ming-Ko. "Hydrology of Beverly Swamp", in Dear, Drake, Reeds., Steel City: Hamilton and Region. University of Toronto Press: Toronto, Ontario, 1987. pp.85-94.
Hamilton Region Conservation Authority Website

The Hamilton Public Library would like to thank the Waterdown East Flamborough Heritage Society for graciously contributing the information used in this webpage.