Groynes cause problems along Huron shore

Point Clark’s shoreline may have less algae and sludge and more sand if the channels (groynes) cut by property owners were filled in, according to Geoff Peach, from the Lake Huron Centre for Coastal Conservation.

Peach says the groynes restrict water flow along the shoreline and cause sludge and sediment to settle in beach areas on both sides of the lighthouse. “They are pretty effective at stopping currents.”

“The sludge tends to gravitate in the pockets. The organic matter and plants decompose and cause an odor.”

The sludge is actually the result of plants and algae that settle in the channels that were dug out by lakefront cottage owners to bring their boats to shore. The vegetation eventually rots and causes a stench. The sand bottom on the beach north of the lighthouse then gets covered in sludge, making it at times undesirable for swimmers to use. The water tends to flow north, gradually picking up the sludge as it runs over/through the groynes, before moving along to the beaches north of the lighthouse.

“When it reaches that point, plant particles and plant matter will interfere with the water flow, causing it to back up and cause an odor,” he says.

Peach says that if the groynes were gone, it would not only help with the sludge and algae build up, but the shoreline south of the lighthouse could see a return of sandier beaches. “The groynes interfere with sand transferring along the shoreline, as they restrict the flow. Filling them would be a very simple way to free up the transfer process.”

Peach says timing is important when filling the channels. “We can’t interfere with fish habitats or spawning practices.”

Lower water levels in the Great Lakes are also a contributor to problems in the area.

Peach says it’s not unusual to have low lake levels and that some of the issues along the lakeshore residents complain of may be reduced when the water levels rise.

“If history is an indicator, the water levels will rise again,” he says. Once levels rise, we can expect to see a change in the beaches. They will be impacted by more wave action.

“I expect we would see less algae growth, as the water will be deeper and cooler.”

There should be a reduction in phragmitis as well, as waves will cause the sand to move, uprooting the plants.”

As for when levels will rise, Peach can not say.

“Water levels tend to change. The 70’s, 80’s and 90’s saw above average water levels, however there was a low period in the 60’s,” he says. “There was an extensive low period in the 30’s.”

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