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The current approach to regulation has brought many benefits to the Lake Ontario-St. Lawrence River basin, but it also has had damaging consequences to the region's environment and is ill-equipped to deal with possible future water supply scenarios. A new approach to water levels and flows is necessary because of some key challenges.

The Current Approach is Outdated

The current approach to regulation is based on conditions from the last century, relying on the water supplies to Lake Ontario recorded from the 1860's to the 1950's. This creates an unrealistic expectation that Lake Ontario water levels can be regulated within a four-foot range (approx. 1.2 meters). However, it is not possible to keep the lake within the four-foot range under extreme water supply conditions, such as those experienced on several occasions since regulation began. Our expectations about water levels must be based on what we know today, not just on what we understood fifty years ago.

The data, technology, and understanding of the causes and effects of fluctuating water levels are vastly superior today to what existed in 1963, when the current plan was instituted. An updated approach to water levels and flows can reflect what has been learned over the past fifty years, and better respond to the region's diverse and changing needs.

The Current Approach is Not Able to Deal with Future Challenges

Just as the region's population, economy, mix of water uses and scientific knowledge are very different today than they were fifty years ago when the current water regulation plan was implemented, the conditions of the future will be different than those of today. The current plan is designed for past conditions, not future ones. It lacks a structured approach to monitor performance and make adjustments when necessary.

A new approach needs to include a system for monitoring the social, economic and environmental impacts of water level regulation, and how global climate change may affect future water supplies and storm events in the basin. Such an approach should allow the IJC's Board to evaluate long-term changes, and be more responsive to future challenges and to the people and interests in the basin.

The Current Approach Does Not Take the Environment into Consideration

The current regulation plan has altered the natural patterns of water level fluctuations on Lake Ontario and the upper St. Lawrence River, and has severely stressed the coastal wetlands. Why is this important? Because healthy wetlands are critical to the well-being of water ecosystems.

Regulation has reduced the diversity of plant life in coastal wetlands, particularly the diverse wetland meadow marsh community that thrives between long-term high and long-term average water levels. Plant species within this community do not tolerate prolonged flooding, but occasional flooding is required to prevent woody plant species from expanding downslope. More importantly, periodic low water-level cycles are required to allow seeds in the bank to germinate and also to arrest the expansion of aggressive emergent plants, such as cattails, upslope into the meadow marsh community. Regulation has disrupted the cycles of wetland rejuvenation and created conditions that favor areas dominated by cattails. In addition, the steeper fall drawdown of Lake Ontario under regulation has reduced needed access to wetlands by fish in the spring.

A more diverse ecosystem can better resist impacts from environmental threats such as pollution and invasive species. Lake Ontario and upper St. Lawrence River coastal wetlands provide breeding and feeding grounds for most coastal life, including several species at risk. Water level patterns have a direct influence on the breeding and nesting success of marsh birds, fish and amphibians that inhabit the marshes. More varied water levels also create more variety in marsh plants, which creates a more productive and robust coastal ecosystem.

For example, Eel Bay is an open embayment wetland surrounded by a state park in the Thousand Islands region of the upper St. Lawrence River. Since regulation began, the diverse wetland meadow marsh community in Eel Bay has almost completely been replaced with cattails. While coastal wetlands on Lake Ontario and the St. Lawrence River have also been impacted by development and pollution, the reduction in diversity seen at Eel Bay is typical of the degradation resulting from water level regulation. It is estimated that more than 50 percent of the meadow marsh wetland area that occurred on Lake Ontario and the upper St. Lawrence River during the mid- to late 1960s has been displaced by cattail-dominated emergent marsh. At many study sites, the loss in area of meadow marsh vegetation since the 1960s exceeds 80 percent.


If action is not taken to restore more natural patterns to the region's water levels and flows, environmental damage to the lake and river will continue. Valuable wetlands will continue to be lost, biodiversity in Lake Ontario and the upper St. Lawrence River will continue to suffer, and the region will not enjoy the improved quality of life or economic opportunities provided by a healthier environment.

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