Question 21. What further actions can be taken to lower water levels and reduce the risk of flooding in 2020?
Outflows will remain high in 2020. The IJC has given the Board authority to continue deviating from Plan 2014 even after Lake Ontario falls below the criterion H14 trigger levels, and this will allow the Board to further increase outflows whenever opportunities arise considering the impacts that these flow increases will have on other interests of the system.
The Board has had authority to deviate from Plan 2014 since 7 May 2019, after Lake Ontario rose above the high water trigger levels known as criterion H14. In light of the present extraordinary circumstances, the IJC has given the Board authority to deviate from Plan 2014 even after Lake Ontario falls below the criterion H14 trigger levels.
The outflow released from June through December 2019 was the highest ever recorded for this seven-month period. High outflows are expected to continue to be released in 2020 as the Board continues to consider all possible measures to lower the level of Lake Ontario as rapidly and as much as possible, heading into next spring. The Board has been reviewing data from the past three years to better understand when potential opportunities to deviate from Plan 2014 might be available over the next several months, and what the effects of such deviations might be on water levels and interests throughout the Lake Ontario - St. Lawrence River system.
Forecasts indicate that Plan 2014 outflows will be very high and at or near maximum values for several months. The IJC's decision will allow the Board to further increase outflows when opportunities arise considering the impacts that these flow increases will have on other interests of the system. These opportunities are expected to remove a small amount of additional water from Lake Ontario to reduce the risk of high water in 2020.
However, the Board stresses that while an outflow strategy can influence water levels, the main driver is weather, especially when wet conditions are as extreme as they were in 2017 and 2019. Likewise, the amount of additional lowering that will be achieved through deviations will largely depend on weather and water supply conditions, and whether or not a flood occurs during the spring of 2020 will also depend on weather conditions and water supplies over the winter and spring months, not the regulation plan. While the Board and the Plan are doing all that can be done, no flow management plan can eliminate the risk of future flooding.
Question 22. Are these high water levels of 2017 and 2019 the “new normal”?
Extreme high water levels are never normal, but they have occurred in the past and they will occur again in the future – when, or how frequently, is uncertain.
The primary cause of high water levels is always the same - wet weather. Record-precipitation caused the record-high water levels in 2017, and persistent, widespread wet weather also led to record-high inflows from Lake Erie and the Ottawa River system in 2019, resulting in new record Lake Ontario levels. Weather and water supply conditions are uncontrolled and highly unpredictable – we know extremes have occurred in the past and we expect they will occur again in the future, so we must be better prepared for the next event, even though it is difficult to know how soon that will be.
Question 23. How can shoreline residents and businesses prepare for potential future high-water events?
It is imperative that shoreline residents and businesses assess and address risk by considering all available options when living near any body of water that can potentially cause damage or harm.
Shoreline property owners have been impacted by two record-high water events within three years. Multi-year high water events occurring in close succession are not new – for example, Lake Ontario rose above 75.50 m (247.70 ft) and caused shoreline damages in 1973, 1974 and 1976. However, the severity of the events in 2017 and 2019 is alarming.
No regulation plan can eliminate the risk of future flooding. The only reliable means of avoiding high water impacts is through shoreline resilience measures
It is impossible to predict with any certainty the frequency of occurrence of such extreme events, but it is highly probable that extreme high and low water events will occur again at some point in the future. In the short term, it is important for residents and businesses with at-risk properties to consider "resilient" approaches to shoreline management and implement strategies to minimize the potential negative impacts.
Unfortunately, there are no simple or easy solutions, but it is absolutely essential to assess and address risk by considering all available options when living near any body of water that can potentially cause damage or harm.
There is not a "one size fits all" solution to preparing for extremes. Some of the options for consideration may include both engineered and non-engineered approaches, or a combination of actions to find the most optimal response to local conditions. Some examples include:
Engineered Resiliency Responses
- Shoreline Protection - seawalls, revetments, groins, bulkheads, etc.
- Beach nourishment
- Flood proofing/ relocating vulnerable structures and roads
- Floating docks/dock extensions/modular board walks
- Marina facility relocations
- Water intake and sewer modifications
- Coastal wetland construction to mitigate losses
- Soft engineering/green infrastructure (e.g. re-vegetation of shoreline)
Non-Engineered Adaptive Responses
- Integrated shoreline management planning
- Zoning restrictions/ setbacks
- Acquisition of vulnerable properties, non-functional marinas
- Improved flood plain mapping/ technical services
- Alteration of recreational boating season
- Cargo load adjustments
- Abandoning non-functional water intakes