GRAND HAVEN, Mich. (WOOD) — Three years after work wrapped up on Grand Haven’s south pier, the U.S. Army Corps of Engineers is turning its attention to the north. Engineers are in the early stages of a plan to renovate the harbor’s north pier.
Liz Wilkinson, the resident engineer for the U.S. Army Corps’ Grand Haven office, says the plan is to replace the lining of the pier and add a wave attenuator to absorb that energy and prevent waves from channeling into the harbor.
“The early harbors built back in the 1800s were like timber cribs filled with stone,” Wilkinson told News 8. “Those were great at absorbing waves, but the timber tends to rot when it is exposed to air. So for the last 50-plus years, we’ve been replacing those with sheet pile walls.”
Sheet pile walls are a common sight in lakeshore towns. They are typically made of steel panels that lock together and work great in the water. But they don’t absorb waves, so that energy gets forced into the harbor, which can spell trouble for boaters.
“Sheet pile is great for the longevity of the wall and of the structure, but it doesn’t absorb any waves. It totally reflects all the waves that come along it,” Wilkinson said. “Even in that reflection, it can actually create resonance where the waves will actually kind of grow together and create bigger waves inside the harbor.”
The remedy is a wave attenuator — or in Wilkinson’s layman’s terms, a big pile of stones that absorbs the wave action. Wilkinson said the stones are usually between 2 and 10 tons and are placed at a strategic point in the pier where they will be most effective.
“Usually around 200 feet of a pier will be replaced with a wave attenuator. For the Grand Haven north pier, the concept design right now is that about 700 feet of the north pier will be replaced with a wave attenuator,” Wilkinson said.
The U.S. Army Corps of Engineers is already working on some preliminary designs, but it can’t make any final decisions until engineers get their findings from a geotechnical investigation, which measures the makeup and stability of the soil under the surface. Wilkinson says that will happen this spring. Using that information, the engineers will finalize their designs. The current goal is to start construction in the summer of 2023 and finish the project by the fall of 2024.
Engineers are relying on two key funding sources to back the project. The U.S. Army Corps of Engineers is allocating $9.5 million for the project: $7.5 million coming from the Infrastructure Investment and Jobs Act and $2 million from this year’s annual spending budget.
“The intention is that that’s all the funding we are going to get, so we are going to make the project fit within that budget,” Wilkinson said.