Editor Note: Keith Termaat reached out to me to republish a post we published about the STORM act. It was a bipartisan bill that President Trump signed in the final days of his administration. Upon reviewing the Township Neighbors Network, I found a fascinating story Keith wrote about the use of Sill Breakwalls along the Lake Michigan shore. It’s a cost-effective and natural-looking method of holding and collecting beach sand and preventing Great Lakes beach erosion. Lake Huron residents may find it a suitable option for their beach or lake easement property.
Off-Shore Sill Type Breakwall Along the Antrim County Coast – Coved Beach
By: Keith Termaat
Like many, I love the natural shoreline and have struggled to maintain it for decades. Yet erosion has been a problem alongshore the Antrim County Michigan coast of East Traverse Bay for years. Water level peaked in 1986; set new records for three years to 2020.
As water’s edge encroached, sections of my modular boardwalk were removed–either to storage or by gale force winds/waves. That walkway guided our grandchildren to avoid dry beach, bluff, Marram grass, and mixed cobble shorebird habitat. In 2015, the boardwalk stretched 70 feet; in 2020, 8 feet into the water.
In 2020, huge waves rolled in unimpeded as a result of crisis high water level and inaction by authorities. A natural limestone barrier reef offshore was destroyed by ice in the ‘Polar vortex’ winters of 2014-15. Sandbars that had formed in the lee of the reef are also gone. As a result, towering storm waves broke onshore. Memorial Day and July storms tore 8+ feet off battered beaches, undermined high bluffs, and caused slides on critical dunes. Waves pounded beaches and bluffs all summer long.
What to do to protect the beloved natural shoreline?
Each of the last several years, neighbors up and down the Antrim County coast installed seawalls as officials did not address water levels and even dumped more water from Lake Superior into already high Lakes Michigan-Huron (Chicago Tribune). Shore protection began with headlands, then high bluffs, and finally coved beaches between headlands.
Lake bottom near here slopes gradually. The bluff is low on our property. So, for 3 years, manual labor tried to preserve the natural shore. After all, it had worked in 1986. Antrim County Erosion Control Officer, Shaffer was consulted. Contractor quotes were obtained each year for shore protection structures.
Finally, Summer 2020 storm damage/erosion, 8+ feet of beach loss, and cockamamie deck over July 4 weekend forced action. July conditions alongshore are illustrated in the photo above. Stakes locate ordinary HighWater Mark – 580.5 feet. I engaged alongshore neighbors who had built protective
structures, walked their sites to review seawalls and see results for me.
A friend showed me a sill-type breakwater built-in 1986 – still standing and keeping ‘sea’ waves away from a high bluff. There was a referral to sill type breakwater built in 2020 and the contractor who built it. He and I closed a deal and began to engineer and build a sill-type breakwater to hold sediment banked by waves and expected to hold wind-blown sand.
The ‘sill type’ breakwater consists of a row of boulders in then 20 inches of water along the 580.5 OHWM, laid end-to-end. Six-nine inches spacing allows surf to drain back to the ‘sea’. The first boulder is a two-ton monster to anchor the breakwater at the south end. All boulders are granite
and weigh 1 – 2 tons. A worker trims juniper along the bluff to make room for riprap on erosion blanket along the low bluff. Larger rocks protect key trees and other features.
For more information check out the Township Neighbors Network