Proposal for Lake Ontario and St. Lawrence River Regulation

Adaptive Management

Adaptive Management Strategy for Lake Ontario and St. Lawrence River

The International Joint Commission is working with the governments in the basin to develop adaptive management as an important tool for improving management of the Lake Ontario-St. Lawrence River regulation plan.   An adaptive management strategy will enable the Commission to take advantage of future scientific and management advances, to assure that the impacts of regulation are those which have been calculated by the model used to develop the regulation plan, and to adjust for possible long-term changes in the amount of water entering the system (“supplies”).  The Commission does not have the resources or capacity to undertake adaptive management on its own, but will work with jurisdictions and stakeholder groups that have capacity for monitoring various effects of regulation to help them focus on which aspects are most important to track.  The Commission will act on the results, as appropriate, using its standard procedures of reviews, consultations and hearings, if necessary, to make adjustments or changes.  The benefits of an adaptive management strategy would apply to any regulation plan, including the present one. Since the adaptive management components will be funded and managed by a community of governments and stakeholders, it will gradually be built up and evolve over time.  The Commission has worked with key funding sources and interest groups to establish a framework for a Lake Ontario-St. Lawrence River adaptive management strategy based on the key monitoring priorities and estimated costs.  The aspects of regulation that are incorporated into or affected by adaptive management include the regulation rules, the directive on deviations from those rules, and governance procedures. 

The Adaptive Management Process

Adaptive management is a formal process for improving decisions that cycles through these steps:

  • Estimate the impacts of a decision using best available models, but identify areas of uncertainty in those model predictions;
  • Make a decision that produces an appropriate balance of estimated impacts;
  • Monitor indicators of the impacts of the decision related to the key areas of uncertainty and compare them to what the models predicted;
  • Change the models if necessary based on monitoring evidence;
  • Change the decision if warranted based on the revised models.

There are two main areas of uncertainty in evaluating the performance of regulation rules for the Lake Ontario-St. Lawrence River system:

  1. Will future water supplies be different from those used to test the rules?
  2. Will the impacts of levels and flows be different from the modeled impacts used in designing the rules?

The adaptive management strategy will address the water supply and impact uncertainties and will support periodic evaluations to determine if new evidence can be used to develop improved regulation rules.  Review of the regulation rules may occur at any time monitoring evidence suggests that it should, but the first review must take place within fifteen years of the implementation of the plan.

The Adaptive Management Committee

The International Lake Ontario - St. Lawrence River Board will oversee an Adaptive Management Committee made up of technical experts who will coordinate the monitoring, research and modeling needed to carry out the Adaptive Management Strategy.  The Committee members will be appointed by the IJC.   They will report to the Board on their work and present periodically their assessment of the monitoring results.  The Board may use information developed by the Adaptive Management Committee to propose modifications of the regulation rules to the IJC.  The Adaptive Management Committee will work with the Board to provide for public input to the adaptive management process.  Changes to the regulation plan will, as always, require approval of the Commissioners. 

Water Supply Research and Monitoring 

The outcomesof regulation rules will depend on the water supplies that occur in the coming years, so there is a potential to improve the rules if more is known about future climate.  The adaptive management strategy identifies three areas in which reduced uncertainty could improve regulation rules:

1. Forecasting
Two categories of forecast in particular hold promise for better regulation, and will have the highest priority for adaptive management research.

Lake Ontario supply forecasts. Better forecasts of supplies could help further reduce flooding along the shores of Lake Ontario and the St. Lawrence River caused by extremely wet winters and severe ice conditions that limit the winter outflow.  If it were possible to improve the six to eight month forecasts of the amount of water entering Lake Ontario during the coming winter and early spring, the regulation rules could be adjusted in the fall and winter depending on the risk of unusually wet conditions in the coming months, and this could reduce property damage along the Lake Ontario coast while still improving wetland health.

Integrated Lake Ontario-Ottawa River forecasts. Independent forecasting systems exist or are under development for Lake Ontario supplies as well as Ottawa River flows, but there is no joint probabilistic forecast of Lake Ontario supplies and Ottawa River flow. An integrated Lake Ontario and Ottawa River ensemble forecasting system would support better short-term (2-4 week) water level forecasts, which could, for example, help the shipping industry forecast the available water draft for ships arriving at the Port of Montreal.

2. Refined deviation triggers
The Proposal for Lake Ontario – St-Lawrence River Regulation includes authority for the Board to deviate from the regulation rules when Lake Ontario levels reach trigger levels.  Right now these triggers are set using statistics based on the historical record.  There are high triggers for each quarter-month of the year that represent levels that are expected to be exceeded 2 percent of the time; the low triggers are levels that Lake Ontario is expected to be below 5% of the time.  Adjusting releases at these triggers improves economic benefits without significant impact to wetlands, but further research might produce even better economic and environmental results using a different mix of target levels.

3. Creation of a coordinated Lake Ontario-St. Lawrence River climate change model
Water supply datasets for the lake and river are needed to simulate the effects of climate change with different regulation rules.  Datasets that reflect many different possible future climates for Lake Ontario have been developed, but there are just a few for the river.  Because the impact of climate change on lake and river levels is so uncertain, it is important to have a wide array of supplies to test regulation rules under different possible futures. Developing river datasets is more difficult because the flow from the major tributary to the St. Lawrence – the Ottawa River – is affected by the operation of a number of reservoirs in its basin.  This adds a significant amount of work to what is necessary for lake supplies because in addition to modeling rainfall, evaporation and runoff, the operating policies for these reservoirs on the Ottawa River have to be determined and simulated to estimate the inflows to the St. Lawrence River.  It is also necessary to have a coordinated model to properly simulate the coincidence of high and low supplies to Lake Ontario with high and low flows from the Ottawa River basin.  The development of a coordinated climate model for these two regions would help assure that regulation rules will work well under different possible future climate conditions.

Environmental Impact Research and Monitoring. 

The Shared Vision Model of the Lake Ontario-St. Lawrence River system combines all of the performance models and the data used to design and evaluate the proposed regulation rules. The Integrated Ecological Response Model portion of the Shared Vision Model demonstrates that the proposed rules will help wetland vegetation, bird communities, northern pike and muskrat (the muskrat is important because it is an indicator for the general health of a riparian ecosystem).  Performance indicators for these elements of the Lake Ontario and upper St. Lawrence River environment played a critical role in plan selection because they were sensitive to water level changes and representative of a broader ecosystem response.  The monitoring design for these four indicators will seek to isolate water level changes from other stressors and drivers that could influence the performance indicator’s response. Efforts have already been initiated to establish mid- and long-term monitoring protocols.  The Integrated Ecological Response Model predicts that the proposed regulation rules will not make a significant difference in the lower St. Lawrence River environment relative to the current regulation rules.  However, there will be an effort to integrate existing monitoring data requirements to ensure that the proposed regulation rules do not result in unexpected negative environmental impacts on the lower St. Lawrence River. 

Economic Impact Research and Monitoring. 

The Flood and Erosion Prediction System portion of the Shared Vision Model indicates that the rules will increase maintenance costs to existing shore protection structures on Lake Ontario, but those estimates rely heavily on the assumptions made by coastal engineers when the model was developed.  The Lake Ontario-St. Lawrence River Study Board recognized the uncertainty in this assumption and suggested that measurements of the actual elevations of the top of structures be made. 

Surveys of some of these structures have already been made and indicate a lot of variability in the height of these shore protection structures, with many structures being higher than previously assumed for these locations.  The higher the shore protection height, the less likely they are to be overtopped, so this limited survey suggests some shore protection structures in the surveyed areas would be less sensitive to the changes in water levels brought about by the proposed regulation rules than is currently estimated by the Flood and Erosion Prediction System.

Although the Flood and Erosion Prediction System shows very little change in flooding with the proposed regulation rules, work has also been initiated to assess the use of a different model - the Flood Tool - to estimate the sensitivity of shoreline flooding impacts with a broader range of storm surge and wave conditions.  Under the adaptive management strategy, measurements of shore protection in more areas would be taken and the use of the Flood Tool evaluated for a number of sites.  The results of these activities will support continued improvements to the Flood and Erosion Prediction System and a refined assessment of potential effects along the Lake Ontario shoreline.

While refinements to the Flood and Erosion Prediction System have the highest priority among the economic indicators, as funding becomes available, the Adaptive Management Strategy will also address updates to model the impacts to recreational boating, hydropower, and navigation. 

Models of recreational boating requirements and use in the Shared Vision Model predict that the proposed regulation rules will tend to provide deeper water in the fall on Lake Ontario and the upper river compared to the current rules, but less depth on the lake and upper river during those years that experience the driest summers.  On balance the models predict slightly negative boating impacts above Lake St. Lawrence because the estimated boating activity in summer months is much higher than in fall.  Future boat ownership and use may well change these assumptions.  Adaptive management might include a targeted survey of boat ownership and use patterns throughout the boating season. 

The proposed regulation rules produce about the same loading conditions for commercial navigation on average as the current rules, but the proposed rules are expected to provide a modest increase in the value of hydropower produced at both the Moses-Saunders and Beauharnois plants.   The Study Board recognized that there was less uncertainty in the models used to evaluate these sectors and that hydropower and shipping agencies already gather much of the data that is needed for tracking performance.  The adaptive management strategy expects data for these sectors to continue to be available in the future for regulation rule evaluations, but updates to the model may be needed. 

Periodic Assessments of the Regulation Rules

Over time, the evidence collected from the water supply and impact research and monitoring may suggest there is need to develop an improved set of regulation rules.  The adaptive management strategy calls for the maintenance of the tools and expertise developed during the Lake Ontario-St. Lawrence River Study to facilitate the formulation and evaluation of regulation rules in the future.

The tools include the Shared Vision Model, the Integrated Ecological Response Model for Lake Ontario and the upper St. Lawrence River, the Integrated Ecological Response Model for the lower St. Lawrence River, the Flood and Erosion Prediction System, a subsequent flood impact analysis tool developed for Lake Ontario to more closely assess local flooding and wave surge impacts, and information management systems to make the latest research and best data readily available.  The Shared Vision Model has already been re-designed for use in adaptive management.  The Adaptive Management Strategy calls for periodic model exercises and training to maintain agency familiarity with the tools needed to evaluate plans.

Adaptive Management of Lake Levels beyond Level Regulation

An adaptive management strategy specifically focused on Lake Ontario – St. Lawrence River regulation  may eventually be incorporated into a broader Great Lakes monitoring structure, once the broader structure is implemented.  Prior to the broader implementation, the Lake Ontario – St. Lawrence River adaptive management strategy will be developed and function independently. 

The Commission established an International Great Lakes St Lawrence River Adaptive Management Task Team to produce a detailed Adaptive Management Plan for the entire Great Lakes-St. Lawrence River basin to address future extreme water levels.  The draft plan is available for review.  In this case, the IJC is proposing this broader Adaptive Management Plan to assist in:

  1. management of Lake Superior and Lake Ontario regulation rules and
  2. management of responses to extreme levels that occur under any regulation regime.

This paper focuses on the adaptive management of the regulation rules; adaptive management of responses outside of the regulation of water levels will take more time to implement because it involves a much greater degree of coordination between the IJC and other agencies and stakeholders.  Implementation of the response element may begin with adaptive management pilots at a local or regional scale that would address water level related problems. It is possible that one or more Lake Ontario-St. Lawrence River pilot projects could start in the next year or two.    Regulation rules and the deviation directive would be subject to adaptive management whether or not there is adaptive management of response actions.


The IJC has always strived to improve its regulation rules over time; adaptive management is a more structured, science-based and effective way of doing it because:

  • Data collection is more purposeful and better coordinated, increasing the chances that the data needed to inform  regulation decisions will be available;
  • On-going evaluation of the rules should be easier because the tools and knowledge needed to assess performance are maintained on a continuing basis, with a relatively small, steady effort.
  • Decisions are more transparent because the community of experts, decision makers and stakeholders that helped build the models used in adaptive management will be sustained in the outreach efforts of the new International Lake Ontario – St. Lawrence Board.


Available as a pdf file: Adaptive Management.pdf