Wattle Update

The winter of 2022-2023 marks the third time that the LQEC has deployed wattles on the streets of the Sherwood drainage basin with the support of the Sherwood Improvement District and Mission Township. These green, straw-filled structures are designed to capture sand and sediment BEFORE these enter the lake. This reduces the sediment loading of the lake and in the long run will allow for greater intervals between dredging. As dredging is very expensive, financially the use of wattles makes economic sense for the Sherwood Lake Club.

Wattles function very simply. Moving water carries sediment. The faster the water moves the more sediment is carried. If the water is slowed down, significant portions of the sediment being carried will fall out of the water. Wattles slow the flow of water at the culverts/storm drains on the streets. The water still percolates through the straw barriers but this slows the flow leading to the accumulation of sediment at that point. What sediment does not enter the lake does not need to be dredged out later.

How effective are the wattles? Here is a picture of one wattle on Falcon (out of approximately 160-170 that are deployed annually) with the sediment it has trapped midway through the winter season.

Not every wattle traps as much sediment as this one does. However, imagine that on average each wattle traps even one third to one half as much and multiply this by 160-170 culverts/storm drains and then multiply the result by 60 years! The quantity of sediment that has entered the lake and contributed to the need for dredging is enormous. In fairness, the entire basin has not been developed residentially for all of the 60 years, but even adjusting the total for that still yields an astounding amount of sediment entering the lake!

The LQEC and Mission Township are continuing to explore alternatives to sanding and salting the roadways during ice and snow events as well as limiting the overall amounts of sand and salt being applied. We appreciate very much the willingness of Mission Township to work toward a solution that preserves the safety of winter travel and protects the lake from excess sedimentation.