Overview

In the spring of 2017, mere months after the outflow regulations known as Plan 2014 went into effect, extremely wet conditions across the Lake Ontario and St. Lawrence River basins caused water levels to rise to record heights over the course of a few weeks. Severe flooding struck the shoreline of both Lake Ontario and the St. Lawrence River, impacting many shoreline residents and businesspeople. High water also caused major difficulties for Indigenous Nations, boaters, commercial shippers, farmers and other interests.

Flood waters returned in the spring of 2019 with water levels breaking the records set just two years earlier, disrupting commercial navigation, damaging shorelines yet again, and harming most, if not all, water uses and interests. The period from late May through the beginning of August 2019 was the worst extended period of high water since record-keeping began more than a century ago. Governments, insurers and private parties spent hundreds of millions of dollars on recovery and resilience work after the two floods. The lives and livelihoods of thousands of people and the operations of many businesses, farms and local governments were disrupted for weeks and months. Some angry parties blamed Plan 2014 for the damaging high water, though technical reviews showed that without the infrastructure and operations under Plan 2014 water levels would have been higher. Others pointed fingers at the appointed International Lake Ontario-St. Lawrence River Board (Board) that can deviate from the rules of Plan 2014 when levels are extreme. A few claimed the Board unfairly deviated too much to help one interest or not enough to help another.

The Board employed several strategies to try and balance the interests of different sectors of the lake-river system between 2017 and 2020, but no regulation of outflows can prevent flooding when the events are so extreme. Members believe that the decisions they made with the information they had available at the time were reasonable and warranted. However, in the wake of those two high-water episodes, Board members have said they could use more information on the incremental impacts to interests and regions of the deviations they considered, particularly information that can inform decisions at the pace with which they need to be made. They asked for more insight and confidence in the potential consequences of their actions. The Great Lakes-St. Lawrence River Adaptive Management (GLAM) Committee, which is conducting a two phased expedited review of Plan 2014, has been working to give the Board what it asked for.

As detailed in this Phase 1 report, the GLAM Committee has produced an innovative Decision Support Tool (DST) designed to give the Board objective information about deviation outcomes. The tool provides broad-based metrics and up-close data about the potential impacts of deviation decisions across interest groups and geographic areas. The DST will not give the Board the power to eliminate extreme high or low water, nor will it make decisions for the Board. The Board will continue to have only a modest ability to influence water levels. Nevertheless, the DST will inform the Board so that it better understands the impacts and uncertainties of deviation options, and thus enables them to make effective decisions while maintaining their ability to be as fair and impartial as possible within the context of the Boundary Waters Treaty (https://www.ijc.org/en/who/mission/bwt) and 2016 Supplementary Order of Approval (https://ijc.org/en/68a).

Why an expedited review of Plan 2014

The 2017 and 2019-2020 high-water events were the result of a confluence of natural occurrences, including excessive precipitation in the Lake Ontario and St. Lawrence River basins and extreme inflows from Lake Erie as well as the Ottawa River, which enters the St. Lawrence River at Montréal. No regulation plan could have prevented flooding in the face of such extraordinary water supplies beyond the design capacity of the St. Lawrence River system. However, the unprecedented nature of the high-water events and the possibility of recurrence, plus a degree of public distrust of Plan 2014, prompted the IJC commissioners to speed up the timetable for a review of the plan by an internal body dedicated to such work — the GLAM Committee. The IJC ordered the expedited review in February 2020 and the GLAM Committee was instructed to explore how Plan 2014 addresses extreme high or low water levels and consider whether the plan’s regulatory processes should be improved or supplemented to better deal with such extreme events. The GLAM Committee also is considering whether the assumptions made about future water supplies for Lake Ontario and the St. Lawrence River should be revisited due to the impacts of climate change.

To assist the GLAM Committee with its review, the IJC named an 18-member Public Advisory Group (PAG), made up of representatives of uses and interests from throughout the St. Lawrence River and Lake Ontario system. The advisory group offered valuable advice to the GLAM Committee during the Phase 1 effort. Through their contributions the PAG increased transparency in the process, provided a detailed assessment of the Phase 1 engagement process, and gained insights and empathy of the impacts and experiences of interests across the entire system.

The GLAM Committee undertook a two-phased approach. Phase 1 of the expedited review had a more narrow and urgent purpose as explained below and was completed in early November 2021. Phase 2 of the expedited review will examine Plan 2014’s response to extreme high and low water on a broader basis, gather more information, continue critical research, and explore the need for any modifications to the regulatory plan. Phase 2 is tentatively scheduled for completion in the fourth quarter of 2024.

The GLAM Committee’s Phase 1 focus: Board deviations

Amid the clamor over two record-breaking floods in a three-year period, and with more high water looming, the IJC directed that Phase 1 of the expedited review focus on a single element: providing Board members with more insight when they made deviation decisions. At the time the Phase 1 effort began, the level of Lake Ontario remained high and water was flowing into Lake Ontario from Lake Erie in near-record volumes. It seemed possible that water supplies would remain perilously high for at least several more years. Increasing the level of confidence in deviation decisions was deemed the most expedient way to prepare for what was feared could be an imminent recurrence of damaging high water. As it turned out, an unusually dry period in the Lake Ontario and Lake Erie basins in 2020-2021 alleviated the immediate threat of high water over that period.

The focus of Phase 1, then, was on providing the best information possible to assist the six-member International Lake Ontario-St. Lawrence River Board (Board), an appointed body that oversees the operation of Plan 2014. The Board has the authority to change the planned outflow, or “deviate” from Plan 2014’s provisions when the water reaches extreme high or low levels.

Outflow regulation, even in the absence of extreme high water, is not a simple task. Lake Ontario’s level can be influenced by adjusting the outflow of water through the Moses-Saunders Power Dam on the St. Lawrence River. Outflow adjustments tend to have a moderating effect on Lake Ontario levels, reducing the rate or extent of a rise or fall, though levels cannot be controlled entirely. The vast lake reacts very slowly to changes in outflow, while the St. Lawrence River has multiple hydraulic zones, each of which reacts differently to outflow alterations. When water levels are not extremely high or low, Plan 2014’s rule curve governs the outflow. When water pushes toward an extreme, one of the five limits built into Plan 2014 can govern outflows. The limits are intended to protect interests on Lake Ontario and the St. Lawrence River such as shoreline property owners, hydropower producers or commercial shippers.

If the lake level reaches pre-determined extreme high or low “trigger levels,” the Board is authorized to deviate from Plan 2014’s rule curve or limits by ordering outflow changes. Per criterion H14 of the 2016 Supplementary Order of Approval, when high level triggers are exceeded the works are to be operated so as to provide all possible relief to riparian owners upstream and downstream, and when water falls below the low level triggers, the works are to be operated so as to provide all possible relief for municipal water intakes, navigation and power purposes, upstream and downstream. These changes are intended to lessen the impact of extreme water levels. The Board also can deviate in certain other cases as per their directives from the IJC. During the high water in 2017, 2019 and early 2020, the Board was regularly under deviation authority and making decisions that resulted in deviations occurring almost half the time from 2017 through the end of 2020. That is, during these periods of high water, the system was managed as often under deviations as it was under normal plan operations. Deviations cannot eliminate extreme high or low water, but they can make a measurable difference in some cases. For example, in the summer of 2017, after the Lake Ontario level had begun to recede from its peak, the Board was able to remove an additional fifteen centimeters (six inches) of water from Lake Ontario. But, as happened frequently in 2017 and 2019-2020, interests on the river and lake sometimes plead with the Board to do more.

Board members found that during these periods of extreme high water they could have made use of more information about potential outcomes of their decisions. Some of these information gaps pertain to tradeoffs — that is, situations in which alleviating the impact of extreme water levels on one interest or region worsens the impact on another interest or region. The Board has struggled to weigh respective impacts in these cases, which are happening in real time and often are accompanied by public outcry from the competing interests. As well, the Board members said they could not judge long-term impacts of possible deviation strategies because of uncertainty about water supplies in the coming weeks and months, a challenge exacerbated by the changing climate.

The Phase 1 effort by the GLAM Committee was aimed at finding ways to improve deviation decisions by providing the Board with better information, including better ability to inform real-time decision-making. Working on a compressed schedule, the GLAM Committee conducted or sponsored targeted research to address key gaps in knowledge, and also developed the DST to consolidate, summarize and visualize that information to support Board decision-making.

Research accomplishments

The GLAM Committee worked to fill information gaps and address uncertainties about deviation-decision outcomes. Its data collection and analysis will inform both the Board and the public of the risks and tradeoffs associated with regulating under extreme high water. The data was used to create the DST and to provide insights into possible new deviation strategies. The DST also can be updated as better information and understanding is developed through the ongoing research programs.

Much of the research conducted or sponsored by the GLAM Committee focused on the impacts of extreme high water on six identified uses and interests on the lake-river complex: municipal and industrial water systems; commercial navigation; hydropower production; lake and river shoreline properties; lake and river ecosystems, and recreational boating and tourism. The GLAM Committee and the ijc also respect and recognize that Indigenous Nations must be included in the review of regulation plans, in addition to the six other key interests, to ensure that Indigenous knowledge and perspectives are part of the plan review process. Engagement and fact-finding about impacts of water-level changes on these communities began in Phase 1 of the Plan 2014 expedited review and will continue in Phase 2. Likewise, public engagement efforts initiated through the PAG in Phase 1 are important to informing critical research.

Among the Phase 1 research efforts:

• The GLAM Committee identified possible new strategies for deviating from Plan 2014’s flow limits by researching the history and functioning of the limits throughout the extreme water conditions and examining opportunities for incremental improvements.
• The GLAM Committee commissioned LURA Consulting to document the impact of high water on municipal and industrial water systems on the river and lake. A separate study by Polytechnique Montréal examined potential impacts on water systems of low wintertime flows on Lake St. Lawrence, the broad section of the river upstream from the Moses-Saunders dam.
• A study by the US Army Corps of Engineers’ Institute for Water Resources provided independent estimates of the impacts of extreme high outflows on the commercial navigation industry. The research examined nine navigation-interruption scenarios that could result from Board deviations and produced estimates of the tons of cargo delayed and financial cost under each scenario. The study and a glam Committee workshop with navigation industry representatives identified how harmful stoppages would be from the industry’s perspective.
• A Clarkson University study of winter flows through the Moses-Saunders dam found that in some situations the Board might be able to deviate more aggressively from the I Limit, which promotes stable ice cover on critical areas of the St. Lawrence River. Separately, River Institute researchers documented that extreme reduction of winter water levels in Lake St. Lawrence of the sort that might result from more aggressive Board deviations could harm a wide range of aquatic organisms.
• GLAM Committee members and researchers at Environment and Climate Change Canada, the US Army Corps of Engineers and other organizations collected and analyzed data on the extreme high water events in 2017, 2019 and early 2020 including the detailed analyses of aerial imagery, municipal damage reports, media reports, and questionnaire responses from over 3000 shoreline property owners. Researchers also conducted detailed analyses of shoreline building footprints and assessed shoreline impacts against the water levels at the time those impacts occurred. The work measured impacts on residential and business properties, marinas and yacht clubs, municipalities and recreational boaters at many locations.
• The GLAM Committee worked with contractors Copticom Stratégies et Relations Publiques, Kennedy Consulting, and usace-Buffalo to undertake outreach activities to staff from municipalities, conservation authorities and other local governments in Ontario, Quebec and New York to gather additional shoreline impact information. People Plan Community and associates were also contracted to work with the GLAM Committee to engage First Nations, Tribal Nations and the Métis Nation that may be impacted by fluctuating Lake Ontario and St. Lawrence River water levels and listen to impacts, experiences and knowledge.
• The US Army Corps of Engineers and the National Research Council Canada developed models that correlated water levels with the number of buildings that would be inundated along the upper St. Lawrence River and Lake Ontario shorelines. The impact of waves and storm surge were estimated as well. Simulations of inundated buildings were also done for the lower St. Lawrence River by Environment and Climate Change Canada.

The Decision Support Tool

A significant Phase 1 accomplishment was creation of a working prototype DST to provide the Board with new insights into and ways to visualize the uncertainties and impacts of possible deviations and the tradeoffs associated with them. Interactive tools such as this are becoming more common in many fields, from sports to health care to water-resource management.

The computer-based DST allows the Board to test the outcome of possible deviation strategies that are presented to them by representatives of the agencies that support the regulation of outflows from Lake Ontario. Until now, information available to the Board during extreme conditions was limited, and was spread across multiple platforms and output types. The approach adopted through the use of the DST is to summarize, synthesize, and create visualizations of a range of metrics across all interests and across a wide range of geographic regions. This information is presented through broad-based metrics that show, for example, the number of shoreline and near-shore buildings on Lake Ontario and the St. Lawrence River that could be inundated by the water levels associated with a proposed deviation, or show the tons of cargo affected and the financial cost if a proposed deviation strategy were to cause flows unsafe for navigation leading to a temporary closure. Both values are plotted over time.

Results can also be displayed through location-specific metrics that define impacts by water level ranges known as “impact zones.” These have been developed to show on-the-ground impacts of proposed deviations for a series of shoreline communities — seven on the Lake Ontario shore, two on the upper St. Lawrence River and two on the lower river. These metrics reflect impacts on residential and business properties; marinas and yacht clubs; recreational boaters; parks, roads and other municipal infrastructure, public and private water systems and agricultural land on the lower river. This approach allows the Board to compare impacts of proposed outflow strategies at multiple locations on the St. Lawrence River and Lake Ontario and understand the tradeoffs inherent in any deviation decision, whether those tradeoffs are between interest groups or between geographic regions.

Along with the challenges of assessing tradeoffs, Board members have long faced uncertainty about future water-supply conditions, a consequence of the fact that long-term weather patterns cannot be accurately predicted. This has made it impossible to be sure that a deviation will play out the way the Board intended increasing the challenges faced by the Board when considering the impacts of any outflow strategy. The DST addresses that uncertainty by providing a range of possible water-supply scenarios and showing the associated impacts so the Board can get a sense of the short-term and longer-term effect of deviations. The Board may test deviation outcomes using the six-month forecast provided by the responsible government agencies in Canada and the United States. They can test the levels that would occur if there were no regulation of outflows or in dozens of other wet or dry scenarios based on the historical record. The Board may even choose from “more extreme-case” scenarios in which the water supply and resulting water levels would exceed those of 2017 and 2019. While there is no guarantee that any of those scenarios will come to pass, the use of variable water-supply scenarios allows Board members to judge what effect a possible deviation could have in the coming months.

Importantly, the DST will not make decisions for the Board, and it cannot eliminate the impacts of extreme high or low water, nor can it eliminate uncertainty associated with such a large, hydrologically dynamic system. However the DST does allow for more informed decision-making, particularly related to how a decision impacts multiple interests across widely separate geographic regions. Board members have tested the DST and found the information it provides to be useful in better understanding risks and tradeoffs. The utility of the DST will only increase as it incorporates more information and as Board members gain more familiarity with it, particularly during real-time, decision-making situations.

Findings and recommendations

This first phase of the expedited review of Plan 2014 serves as a good example of adaptive management, which draws on new data and research to adjust management of a system to changing conditions. Information was gathered from people, businesses and institutions that were directly impacted by the extreme high water in 2017, 2019 and early 2020. Technical studies focused on the impact of high water on other uses and interests, and also how this information could be used by the Board in making decisions around deviations from the Plan 2014 rules and limits.

Much of this information formed the underpinnings of the DST, which will help the Board assess impacts, tradeoffs and uncertainties associated with extreme high water and the potential outcomes from deviations strategies with the goal of enabling the Board to make decisions in future high-water and low-water situations that are better-informed and more effective.

Through the Phase 1 effort the GLAM Committee established a number of key findings (see side box) that will help frame activities to be carried out to further inform Board deviation decision-making and in setting priorities for Phase 2 of the expedited review.

As the Phase 1 effort ended in the fall of 2021, the GLAM Committee has identified six recommendations to the IJC as the expedited review moves into Phase 2.

A. Indigenous Relations Building continue into Phase 2 and beyond.
B. Public Outreach and Engagement continue in Phase 2 and for the longer-term adaptive management process.
C. The DST should be considered a dynamic tool that needs continual updates and improvements. Resources need to be dedicated to this.
D. The Board should use the DST to prepare for the next crisis situation. Board members should continue learning how to make use of the DST.
E. Data gaps should continue to be filled and new technologies explored.
F. Phase 2 of the Expedited Review should provide for a fulsome review of Plan 2014.

Phase 2 of the expedited review of Plan 2014 will include analysis of possible changes to the plan’s outflow rules, limits and “trigger levels” for Board intervention. It is expected to be completed in approximately three years.