International Lake Ontario - St. Lawrence River Board

Section 4: Regulation

4.1 What does the ISLRBC regulate?
4.2 How does the ISLRBC go about regulation?
4.3 Who are the Regulation Representatives and what are their duties?
4.4 What are the criteria that the Board uses in making management (regulation) decisions?
4.5 What other regulations and standards does the ISLRBC use in making its decisions?
4.6 What authority does the ISLRBC have to consider individual interests when setting Lake Ontario outflows?
4.7 What actions do the IJC and ISLRBC take to react to low water supplies and avert extreme low water levels in Lake Ontario or the St. Lawrence River?
4.8 Can water be stored on Lake Ontario to provide a buffer against low water conditions in the Thousand Islands and/or Montréal?
4.9 Are there ways to address low water problems other than through regulating water levels?
4.10 Should low water conditions continue for a number of years, what are the implications to the Board's approach to controlling water levels and to water users above and below the Moses-Saunders Dam?
4.11 Should the Board have a contingency plan in place if “drought-like” water supply conditions continue, even though forecasted weather conditions may not predict drought-like conditions?
4.12 If a multi-year trend to lower Lake Ontario water levels emerges, will the Board be able to maintain sufficiently high water levels above and below the Dam to stay above the lowest level needed to maintain Seaway operations?
4.13 What adaptive measures should water users and property owners be taking above and below the Dam to protect against adverse impacts, and will the Board be taking actions to encourage such measures to be implemented?
4.14 Doesn’t knowing the snow pack provide a reliable indicator of the water supplies for the spring and summer season?
4.15 Can Lake Ontario water levels be reduced in the fall of each year to provide a buffer against high water supplies the next spring?
4.16 What is criterion (k) and what triggers it during high or low water conditions?
4.17 What is criterion (h)?
4.18 What is criterion (i)?
4.19 Why doesn't the Commission use criterion (i) as the upper limit for water level regulation on Lake Ontario?

 

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4.1 What does the ISLRBC regulate? [top of page]

The ISLRBC regulates Lake Ontario outflows, ensuring they meet the requirements of the Commission's Orders of Approval. The Board operates under the current regulation plan (Plan 1958-D) and conducts special studies as requested by the Commission. This regulation plan reflects the natural rhythms of the Lake Ontario-St. Lawrence River System. Though the ISLRBC regulates outflows, the system is primarily influenced by natural processes, such as inflow from Lake Erie, weather patterns, and wind (see Section 1, “Influences on Water Levels and Flows”).

4.2 How does the ISLRBC go about regulation? [top of page]

The Board reviews the hydrologic and water level conditions and sets a regulation strategy through meetings that occur on at least a monthly basis. The regulation strategy generally consists of a directive to the operators to release flows as specified by the regulation plan or to deviate from the plan flows. If deviations are authorized, specific flow rates and their duration above or below the plan flow are prescribed, when possible. In many cases, deviations are authorized only if certain water level or flow conditions are encountered and only up to specific limits.

On the basis of the Board’s regulation strategy, the Board regulation representatives consult with the Operations Advisory Group (OAG) on a weekly basis (each Thursday) and direct that the flow be adjusted to the required rate, effective Saturday morning of each week (typically). In the case of unusual events, emergencies, and/or disputes over the flow rate between the regulation representatives and the OAG, the Board will be asked to meet on an emergency basis through a teleconference or via electronic means.

4.3 Who are the Regulation Representatives and what are their duties?  [top of page]

There are two Regulation Representatives that carry out the day-to-day regulation activities of the Board. The Board’s American Regulation Representative is the District Engineer at the Corps of Engineers’ Buffalo, New York office, and its Canadian representative is the Manager of the Great Lakes - St. Lawrence Regulation Office of Environment Canada in Cornwall, Ontario. Regulation Representatives have strong technical backgrounds and are typically professional engineers. They are supported by a team of water management engineers and technical experts. Among other duties, the Regulation Representatives:

  • Perform the weekly regulation computations according to the regulation plan.
  • Advise the Board on potential regulation strategies (including any discretionary deviations) and ice management.
  • Ensure that regulation operations follow the Board’s adopted strategy.
  • Act on behalf of the Board in emergency situations where immediate decisions to change flows may be needed.
  • Collect and evaluate water level, flow, ice, and hydro-meteorological data related to outflow regulation.
  • Act as the Board’s technical liaison and monitor and coordinate flow regulation activities with navigation and hydropower entities.
  • Provide expert technical advice and data (e.g., water level and outflow data and forecasts, datasets, statistics, etc.) to stakeholders, the public and media.
  • Undertake studies and analyses as necessary to improve and facilitate regulatory operations and decisions.
  • Ensure the accuracy of reported water level and flow data relevant to regulatory operations. 

4.4 What are the criteria that the Board uses in making management (regulation) decisions?  [top of page]

The 1956 Orders of Approval provide 11 criteria for setting flows through the project. They address:

  • regulated outflows from Lake Ontario and their effect on the minimum level of Montréal Harbour,
  • outflows during the annual spring ice break up in Montréal Harbour and during the annual flood discharge from the Ottawa River,
  • minimum regulated outflows to secure the maximum dependable flow for power generation, and
  • both upper and lower target levels for water levels on Lake Ontario. 

These criteria are to be met when water supplies to Lake Ontario are within those experienced during the period of record (1860-1954). When water supplies are higher than those experienced during this period, the outflow from Lake Ontario is to be regulated to provide all possible relief to upstream and downstream property owners. When supplies are less than those during this period, the outflow is to be regulated to provide all possible relief to navigation and power interests. The full text of the 1956 Orders of Approval, including the 11 criteria, is available online.

4.5 What other regulations and standards does the ISLRBC use in making its decisions?  [top of page]

The current regulation plan (Plan 1958-D) determines outflows that meet the criteria established under the Orders of Approval. The IJC has also granted the Board of Control the authority to release flows that deviate from those specified by the Plan if the Board determines that such deviations will provide benefits to one or more interests without resulting in any significant negative impacts to other interests. Except in the case of extremely high or low water supplies, the deviations authorized by the Board are generally small in magnitude, short in duration, and are often offset with equal and opposite flow changes as soon as conditions permit.

4.6 What authority does the ISLRBC have to consider individual interests when setting Lake Ontario outflows?  [top of page]

In 1961, the IJC gave discretionary authority to the ISLRBC to depart temporarily from the regulation plan flow when a deviation would provide relief from adverse impacts to any interest without appreciable adverse effects to any of the other interests. At various times, this authority is used to assist shoreline property owners, recreational boaters, navigation, hydropower, and other interests.

4.7 What actions do the IJC and ISLRBC take to react to low water supplies and avert extreme low water levels in Lake Ontario or the St. Lawrence River?  [top of page]

The criteria and regulation plan aim to maintain Lake Ontario levels above 74.15 m (243.3 ft.) from April 1 through November 30, even under very dry conditions. The operating plan was designed to reduce outflows as conditions become drier, within defined limits. When conditions permit, the Board may deviate from the plan in order to reduce outflows even further (i.e., store water for even drier times) or to increase outflows (i.e., to release water to meet a specific short-term need). Under the most extreme dry conditions, all possible relief is provided to affected interests specified by the Orders of Approval.

4.8 Can water be stored on Lake Ontario to provide a buffer against low water conditions in the Thousand Islands and/or Montréal? [top of page]

Yes. In doing so, however, relevant interests need to be considered and balanced, such as water levels in the Thousand Islands and/or Montréal are considered along with other interests. In such a system, no one interest can be perfectly satisfied all the time to the detriment of all other interests.

4.9 Are there ways to address low water problems other than through regulating water levels?  [top of page]

Yes. The design and siting of water intakes and recreational boating facilities should take into account the entire range of water levels to be expected. In general, no Federal, N.Y. State, Ontario Provincial, or Quebec Provincial regulations have been implemented to assure that adequate designs are used. For recreational boating facilities, adequate investment in dredging, including securing necessary permits, is also effective in dealing with low water levels that should be expected to occur on occasion as a result of low water supplies.

4.10 Should low water conditions continue for a number of years, what are the implications to the Board's approach to controlling water levels and to water users above and below the Moses-Saunders Dam? [top of page]

Under the current Order of Approval (1956), the ISLRBC follows the regulation plan, known as Plan 1958-D, which decreases the outflow from Lake Ontario as the level decreases subject to a number of limits. The ISLRBC also has discretionary authority to deviate from plan flows to help one or more interests if this can be done without causing appreciable harm to other interests. Discretionary deviations are set by the ISLRBC based on a risk analysis that looks at all factors and all affected interests upstream and downstream. The outflow may be decreased under discretionary deviations to store water on Lake Ontario for future use, but such action is based on the needs and possible impacts to users both upstream and downstream. Finally, when the water supply to Lake Ontario is below a certain historical range (1860-1954), the outflow is set under “criterion k” of the Order of Approval to provide all possible relief to navigation and hydropower interests. The ISLRBC will try to share the “pain” from the dry conditions to water users both above and below the dam.

4.11 Should the Board have a contingency plan in place if “drought-like” water supply conditions continue, even though forecasted weather conditions may not predict drought-like conditions?  [top of page]

The use of discretionary deviations is in a way contingency planning in that the risk analysis takes possible future conditions and impacts into account. However, since the ISLRBC realizes that forecasted weather conditions are not reliable for more than a few days into the future, the risk analysis used by the ISLRBC considers the possible impacts of high, average and low water supplies in the future. History has shown that we cannot count on the continuation of a drought any more than we can count on future precipitation. It is simply not possible to predict future water supplies, so all reasonable possibilities must be taken into account.

4.12 If a multi-year trend to lower Lake Ontario water levels emerges, will the Board be able to maintain sufficiently high water levels above and below the Dam to stay above the lowest level needed to maintain Seaway operations?  [top of page]

The regulation of Lake Ontario outflows allows for some management of natural water supplies, some balancing of natural supplies above and below the dam, and thus for some reduction in negative impacts. No regulation plan can create water supplies, and thus no regulation plan can maintain sufficiently high water supplies above and below the dam under any multi-year trend of lower Lake Ontario water levels. When extreme high or low water supply conditions occur, the resulting water levels would also be extremely high or low under any plan. Water levels would be higher or lower to a degree under different regulation plans, but the overall trends would not be different. No regulation plan affords enough control to affect the overall trends.

4.13 What adaptive measures should water users and property owners be taking above and below the Dam to protect against adverse impacts, and will the Board be taking actions to encourage such measures to be implemented?  [top of page]

The ISLRBC always encourages water users and property owners to plan for the full range of water levels that have been experienced historically. Recommending specific adaptive measures is beyond the purview of the ISLRBC, but information on this topic is readily available, including in some of the agency publications provided on the publications page of the ISLRBC website.

4.14 Doesn’t knowing the snow pack provide a reliable indicator of the water supplies for the spring and summer season?  [top of page]

Since on average 80% of the water coming into Lake Ontario comes from Lake Erie, the correlation between the snow pack in the local drainage basin of the lower lake and its subsequent spring and summer level is very low. Most of the water coming into Lake Ontario at any one time is not from precipitation over its local drainage basin and the lake itself, but is flowing over Niagara Falls from Lake Erie. Even Lake Erie receives on average 78% of its water supplies from the Great Lakes above it; therefore the snowpack in its local drainage basin is an unreliable indicator of spring and summer water supplies. In fact, on the Ottawa River, where the snow pack is a better indicator of the spring freshet, so many other factors come into play in determining the peak flow, that the correlation is still not perfect. Other factors include how frozen the ground is when the snow melts, how dry the soil is, how fast the snow melts and whether the snow sublimates, that is evaporates directly from snow into water vapour without first turning into water. Most crucial is whether it rains at the same time as the snow is melting, this generates the most runoff.

4.15 Can Lake Ontario water levels be reduced in the fall of each year to provide a buffer against high water supplies the next spring?  [top of page]

Yes. In doing so, however, relevant interests need to be considered and balanced, such as water levels in the Thousand Islands and/or Montréal are considered along with other interests. Reductions in fall levels can result in negative environmental consequences for water-level dependent wildlife and fish species that use wetlands throughout the fall, winter, and spring periods. In the Lake Ontario – St. Lawrence River system, no one interest can be perfectly satisfied all the time to the detriment of one or all other interests.

4.16 What is criterion (k) and what triggers it during high or low water conditions?  [top of page]

Criterion (k) allows for flexibility as part of the IJC’s Orders of Approval for the St. Lawrence project. It is triggered when extreme high or low water supplies occur that are outside the range that was used to design the regulation plan. Based upon the supplies received and all other factors occurring at the time, the Board may recommend to the IJC that criterion (k) be invoked. Once invoked by the IJC, operations under criterion (k) commence, subject to any conditions that the IJC may impose.

  • Under extreme high supplies, criterion (k) provides that all possible relief be given to riparian property owners upstream and downstream of the project.
  • Under extreme low supplies, criterion (k) provides that all possible relief be given to domestic and sanitation, hydropower, and navigation interests.

If water supplies are higher, the Board may be directed by the Commission to release flows to provide relief to riparian interest upstream and downstream of the project. If water supplies are lower, the Board may be directed by the Commission to release flows to provide relief to domestic and sanitary, navigation and hydropower interests. The authority for the Board to operate according to criterion (k) has to be specifically directed by the IJC, typically following a recommendation from the Board. Historically, the Board has considered several factors when recommending that the IJC invoke criterion (k), including the recent and forecast supplies to the lake, the current level of the lake, the chance of exceeding the criterion (h) or (j) levels, the amount of snowpack on the basin, soil moisture conditions, and other hydrologic factors.

The Board does not wait until water levels have exceeded the upper or lower limits before recommending implementation of criterion (k). As specified in the Orders of Approval, the use of criterion (k) is predicated on the receipt of water supplies to the system that exceed those experienced prior to the development of the current regulation plan, Plan 1958-D. The Board continually monitors the supplies received and anticipated in the near future and compares them to the maximums and minimums received prior to 1955 in order to determine if the supplies have or can reasonably be expected to exceed the maximums or minimums as recorded prior to 1955.

4.17 What is criterion (h)?  [top of page]

Criterion (h) sets an upper limit for Lake Ontario. It expresses the IJC’s intention that with regulation the monthly mean levels of Lake Ontario be below the elevation of 75.37 metres (247.3 feet - IGLD 1985) when water supplies are within the range seen before the construction of the project.

4.18 What is criterion (i)?  [top of page]

Criterion (i) expresses the IJC’s intention that monthly mean levels above the elevation 75.07 metres (246.3 feet - IGLD 1985) not occur more frequently with regulation than would have occurred prior to the project with the same water supplies. Criterion (i) keeps water levels from being maintained near the top of the regulation range.

4.19 Why doesn't the Commission use criterion (i) as the upper limit for water level regulation on Lake Ontario?  [top of page]

Criteria (a) through (k) were developed as a total package that is workable given water supplies within the range of those experienced before the project was built. This set of criteria includes criterion (i), which specifies that the frequency of monthly mean elevations of approximately 75.07 m (246.3 ft) or higher shall be reduced. The target upper limit for Lake Ontario water levels is specified in criterion (h) as 75.37 m (247.3 ft). Treating the criterion (i) level as an upper limit would be equivalent to narrowing the target range of levels by one foot. This would be a significant change to the Orders of Approval which would make the other criteria more difficult, and perhaps impossible, to achieve.