Posted on January 19, 2021
MOUNT PLEASANT — Town Council wants the Army Corps of Engineers to reconsider where it will place sediment to renourish the once-pivotal shorebird sanctuary Crab Bank out of concern for Shem Creek and the potential negative economic impacts.
The rookery eroded in recent years because of weather and tides. And the Corps now plans to use dredged material from the Charleston Harbor deepening project to replenish the habitat for pelicans and other shorebirds familiar to the Southeastern coast.
Crab Bank, located near Shem Creek, is now just a sliver of land. The renourishment project would restore 28 acres of prime nesting habitat for coastal birds.
Mount Pleasant leaders are concerned the proposed project could negatively affect Shem Creek and cause negative economic impacts to the town and its residents. The Corps’ plan is to place about 660,000 cubic yards of dredge material at the site. This total is more than the amount used in the 1950s to create the upland.
A resolution passed unanimously by Town Council on Tuesday says the increased material will cause a connection to the mainland within 10 years. The material will increase sedimentation to both access channels and the mouth of Shem Creek, the resolution said. In turn, Crab Bank will lose its habitat value as a bird rookery because predators will have access to it.
Sediment at the rookery has drifted northward towards the mouth of Shem Creek over time. Initial plans for the renourishment threatened to “further choke the creek,” according the Town Administrator Eric DeMoura.
The Corps revised the plan to place the sediment farther south in a direction more preferable by the town.
“But it hasn’t been far enough to mitigate the type of impacts that we foresee coming in years ahead,” DeMoura said.
The town does not oppose the restoration of Crab Bank but wants the sediment placed even farther south in the harbor to protect the creek and the people who rely on it for recreation and commerce.
In a news release Wednesday, the town said its alternative plan for the placement of the sediment would extend the life of Crab Bank and slow the formation of a land bridge to Patriots Point.
“It doesn’t take many scientists to actually show what happens over the course of time here,” DeMoura said. “But one can easily see that while this was 350,000 cubed yards dumped back in the 1950s, that we are in danger when more than twice that amount gets dumped in just a few months from now.”
The Corps said last year that work to restore the bank was slated to start in September and should be completed in the following winter.
Research economist Dr. Joseph Von Nessen was hired by the town to research the economic impact of reducing the depth of Shem Creek. His study, which includes projections from local businesses, estimates the town would suffer an economic loss between $82.9 million and $126.1 million annually by a reduction to the creek.
The extent of the loss would depend on the amount of natural shallowing, Von Nessen’s report said.
About half of businesses reported that they would be negatively impacted by creek shallowing, Von Nessen said.
The proposed project could cause an economic impact as high as $126 million in five years when shallowing is expected to reach 6 feet. Von Nessen said this impact is associated with about 1,432 jobs in the area.
“I think an important point to re-emphasize that most survey respondents do perceive the trade-off between the two and recognize and value both,” Von Nessen said. “They value preserving the economy of the waterfront district as well as Crab Bank.
Town Councilman Howard Chapman said it is critical that the town meets with U.S. Sens. Tim Scott and Lindsey Graham and Rep. Nancy Mace to ensure they understand the significant of what the Corps is doing to the community.
“This is important enough to go see our legislators, and I mean congressional legislators, because they’re the ones who sign off on the budget for the Corps of Engineers,” Chapman said.
Jeff Livasy, the civil works chief for the Corps’ Charleston district, said the service’s models do not show any threats to Shem Creek.
In 2018, the Corps thought it had reached a compromise with Mount Pleasant by agreeing to shift the sediment to the southeast, Livasy said. But leaders in the town remained unsatisfied.
Livasy said there are now four constraints to moving the sediment even farther south. Whatever adjustments made to the plans must create the same amount of habitats for shorebirds. Revisions to the plans must also fit within the environmental boundaries that were established when the project was first studied.
Cost is one big constraint. Livasy said there is no funding to accommodate additional costs.
But the Corps is unsure if making another shift would even add to the price. It is projected to cost about $300,000 to place the material on Crab Bank, Livasy said.
Lastly, an additional adjustment must be constructible.
Livasy said the Corps is willing to meet with the Town Council about their concerns and the associated constraints.
DeMoura said people rely on Shem Creek both to make a living and for their enjoyment.
Source: postandcourier
