Thursday, July 2, 2020

Record high levels in Lake Erie & Lake St. Clair


The Lower Thames Valley Conservation Authority says there are record high water levels on both Lake Erie and Lake St. Clair.

This has resulted in a risk of shoreline flooding on both lakes, a risk of erosion and damage to shoreline protection works.

“Water levels on both Lake Erie and Lake St. Clair have broken records,” LTVCA officials stated.

“In May, Lake Erie broke the all-time monthly average record set in June of 1986. Since the end of May, average water levels on Lake Erie have risen approximately 10 cm. On Lake St. Clair, average water levels at the end of June exceeded the all-time monthly record set in October of 1986 by about 8 cm.”

LTVCA officials added: “Overall for the Great Lakes, average water levels at the end of June were above the June average monthly record highs for all lakes. Water level forecasts suggest that by the end of July, Lake St. Clair will be at roughly the same water levels, whereas Lake Erie is expected to have fallen by about 10 cm.”

With such high water levels, shoreline areas are highly vulnerable to shoreline damage, flooding and erosion, LTVCA officials stated.

“There are currently low lying shoreline areas in the Lower Thames Valley Conservation Authority jurisdiction that are constantly under water, including some roadways. People should try to avoid these areas if possible,” LTVCA officials stated.

“Sustained winds can lead to water level changes and waves that cause shoreline issues. Strong winds out of any direction will have an impact on some area along our local shorelines. Wind conditions over the lakes can change quickly and with little warning. This is especially true during the summer when thunderstorms are more frequent. Onshore winds forecasted above 25 km/hr are likely to start causing problems.”

The areas most frequently impacted include: Lighthouse Cove when winds are out of the north or west; Erie Shore Drive when winds are out of the south (WSW through ESE); the bay side of Erieau when winds are out of the east or north; Shrewsbury when winds are out of the east (NNE through ESE); and Rose Beach Line when winds are out of the east (NNE through S), LTVCA officials stated.

“Of course, other shoreline areas are also susceptible,” LTVCA officials stated.

“The bluff areas on the Lake Erie Shoreline are also at a greater risk of erosion due to the high lake levels, especially when there are onshore winds and waves.”

Summer thunderstorm activity has also proven to be an issue in these shoreline areas, officials say.

“Pop-up thundershowers are not always forecasted and the sudden strong winds associated with them can produce unpredicted waves and water level changes that impact shoreline communities,” LTVCA officials stated.

“Heavy rains associated with thundershowers could also cause flooding in low lying shoreline areas. Due to the high lake levels, the groundwater table is high and storm water sewer systems and local watercourses are full with lake water. As a result, rainwater is not draining properly from these areas. Any water from upstream making its way downstream on these watercourses into these shoreline areas could cause additional flooding.”

Shoreline residents need to pay attention as local conditions change and prepare accordingly, LTVCA officials say.

“Please contact your local municipality should unexpected flooding and/or erosion events occur that may impact roadways and other public infrastructure,” officials say.

“More importantly, people need to keep themselves safe. Should an event occur, people should take extra caution and avoid the shoreline and any waterways with elevated water levels. The waves on the lakes can be strong, and the shoreline and the banks of waterways can be slippery and unstable. There could also be hazardous debris within the waves and water which could be thrown onto the shoreline. Standing water can also present unseen hazards. Children and animals should be kept away from the water.”

LTVCA officials say this is a standing message issued for the month of July.

Should weather forecasts suggest a sustained wind event likely to cause shoreline issues, this message will be upgraded, LTVCA officials stated.

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