Thames River Much Healthier Without Springbank Dam

Constructed at its current location in 1929, Springbank Dam was built to create water supply reservoirs and for recreational activities. As the city expanded, means by which water was collected and stored changed, as new technology became available. These obsolete reservoirs have since been replaced by park, and the pump house converted to washrooms. Plenty of recreational activities exist, as canoeing, kayaking and fishing are still enjoyed along the river.

Contrary to what many believe, Springbank Dam serves no purpose in flood control as is evident by London’s famous flood in 1937. In fact, the threat of flooding wasn’t resolved until Fanshawe Dam was completed in 1952. Springbank Dam has been nonoperational since 2008 when after repairs, debris in the river caused one of the gates to shift and bolts securing that gate’s hinge sheared off. Since this time, the health of the river has improved.

Dams are unhealthy for rivers in many ways. They create an unnatural barrier preventing fish and other aquatic life from moving freely up and down stream. The decreased flow of water causes sediment and nutrients to build up and an increase in water temperature. These factors promote the growth of harmful bacteria and algae. When Springbank Dam was operational, stagnant, slow moving water, made the river appear dirty and produced the aroma associated with it for so many years. Glancing at the river when passing by, it now appears much cleaner than it did when the dam was operational. It is not just an appearance, the river is in fact cleaner. The increased flow of water keeps a fresh supply coming from upstream and moves sediment, nutrients, and treated sewage from Greenway Pollution Control Plant out of the city.

Many Species at Risk inhabit the Thames River and its watershed. Ten species of fish and ten species of freshwater mussel currently found in the river are listed as Species at Risk. Seven species of snake and six species of turtle that are currently listed as Species at Risk reside within the Thames River watershed. Several factors have led to the decline of these species including: habitat loss, pollution, and siltation, all negative effects caused by Springbank Dam.

Seven of the eight turtle species residing in Ontario are now listed as Species At Risk. Six of these species are found within the Thames River Watershed. Among these species is the Spiny Softshell Turtle, currently listed as threatened. Habitat loss and pollution are two of this species biggest threats; both issues have improved since Springbank Dam failed. With the river back at its natural level, nesting habitat for these turtles has greatly increased. The Upper Thames River Conservation Authority’s Species At Risk Reptile Team has been working hard over the years to protect these turtles and their nests. This year saw them protect 175 Spiny Softshell Turtle nests, the most ever, proof this species is benefiting without Springbank Dam.

With the Thames River now at its natural level, reforestation is occurring, increasing the size of the riparian zone. A riparian zone is the area of vegetation where the land and river meet. This area helps reduce pollution and improve water quality. Along the Thames, many beneficial native species of tree, shrub, wild flower, and grass, make up this riparian zone. Their root systems stabilize the bank, reducing erosion and the amount of sediment that ends up in the river. Less sediment means a cleaner river bed which improves the habitat where fish spawn.

Riparian vegetation also reduces the amount of harmful nutrients and pesticides that enter the river with run off following periods of rain. Although these nutrients occur naturally in aquatic ecosystems, high levels result in nutrient pollution. Many of these nutrients and pesticides are applied to lawns by golf courses, homeowners, and city parks along the river. Most notable are nitrogen, phosphorus, and potassium found in fertilizers. Too much nitrogen and phosphorus in the river can cause water to become polluted.

Trees in the riparian zone provide nest sites for birds. Wood and debris that fall from these trees into the river provide shelter, current breaks and habitat for fish and aquatic insects. The shade created by these trees regulates the water temperature benefiting several fish species, as most fish, including many on the Species at Risk list, thrive in cooler water.

Leaves, twigs and other organic matter that fall into the river and riparian zone, provides food for many aquatic organisms. Increased vegetation along the banks helps slow the force of the water after heavy rains, which prevents erosion of the river bed. When a riverbed erodes the local groundwater table is lowered, which has negative effects on the environment. These negative effects include: loss of wetlands and riparian vegetation, more frequent and severe drought, reduced biodiversity and wildlife habitat loss.

Evidence of this reforestation and increased size to the riparian zone is most easily noticed at Springbank Park on both sides of the river, from the dam, upstream to the old pump house. Beneficial reforestation is not limited to this section of the river as it occurs in many areas as you follow the river upstream.

Native species in the riparian zone where natural reforestation is occurring along the Thames River include: Poplar, Aspen, Cottonwood, and Sycamore. Smaller fruit bearing trees and shrubs, like Dogwoods and Chokecherries, are also found. Migratory birds use the Thames River as a highway, feeding on various organisms such as insects, fish, and berries. These same organisms provide food year round to resident birds. Birds nest and raise their young in these same trees and shrubs. Native wild flowers such as Milkweed are growing in areas that with Springbank Dam operational would otherwise be underwater. Milkweed is critical to the survival of the Monarch Butterfly, as it is the only plant consumed by Monarch caterpillars. Other wild flowers now abundant along the banks of the Thames River are Joe-Pye-Weed, Goldenrod, and Jewel Weed. Jewel Weed is a magnet for Hummingbirds. A quick look over the large patches, especially during migration, reveals these beautiful little birds. Joe-Pye-Weed, a mid season bloomer, and Goldenrod, a late season bloomer, are both beneficial to pollinators such as Bees and Butterflies. Nectar from the late blooming Goldenrod is a favourite food of adult Monarch Butterflies who begin their 3000km migration to Mexico in early September. Mammals such as Beavers can be found nibbling on the Poplars, American Mink slip through the dense cover within the riparian zone, as do Squirrels and Chipmunks. Reptiles and amphibians such as snakes, frogs, and toads call this area home.

Repairing Springbank Dam will raise water levels to an unnatural level. The natural reforestation and beneficial riparian zone will be flooded and destroyed. Water and air quality will suffer and so too will many plant and animal species, some of them Species at Risk. Nesting habitat of threatened turtles will be unnecessarily submerged, and the slow moving, stagnant water that so many Londoners associate with the Thames will return. Future repairs will cost taxpayers millions, as new studies, research, and engineering will be required as the previous design clearly failed. A $5 million law suit launched by the City of London against the contractors hired to repair Springbank Dam is expected to hit the courts next year. If money previously spent on this project is recouped by this lawsuit, it could be spent addressing the many other issues facing our city. There is no plan for what the city intends to do with Springbank Dam in the future, but with a municipal election on October 27, 2014 it is an issue I will be discussing with my mayoral and ward candidates before I vote. If you wish to keep a healthy and diverse ecosystem and save Species at Risk in the Thames River, then leaving Springbank Dam nonoperational, thus maintaining natural water levels, is the solution.

Good birding,
Paul