The National Park Service says it is planning a massive restoration of the crumbling sea wall around Washington’s scenic Tidal Basin and a re-landscaping of the shoreline there and in adjacent West Potomac Park.
And the Martin Luther King Jr. Memorial, the Jefferson Memorial and the Franklin Delano Roosevelt Memorial are on the basin and serve as striking backdrops.
But parts of the basin’s sea wall have been sinking for years, and the structure and its walkway are often submerged by tidal inundations that leave behind debris, trash and dead fish when the water recedes.
One section near the Jefferson Memorial is “underwater twice a day every day,” Mike Litterst, spokesman for the Park Service’s National Mall and Memorial Parks, said Thursday.
“We rerouted the trail in that area to get it further back from the edge,” he said. “We did that 20 years or so ago, and it’s underwater, not every day but a couple times a month,” he said.
In some spots, the sea wall “has settled between three and four feet” since it was rebuilt in the 1930s and ’40s, he said.
“And at that same time, the sea level rise has caused the Tidal Basin to rise by a foot,” he said. “So we have water four feet higher than it was intended to be when they built that.”
In some sections, vegetation is growing out of the wall.
A dozen years ago, the Park Service spent more than $12 million to repair the section of the sea wall in front of the Jefferson Memorial, where it was slipping away and sinking into the mud at the bottom of the basin.
Now, the Park Service says a two-part, $5.7 million contract has been awarded to begin the planning and compliance process for the proposed restoration project.
The contract has been awarded to HDR, an architecture, engineering and planning firm based in Omaha, and Moffatt & Nichol, a Long Beach, Calif., engineering firm with waterfront expertise.
The Park Service said it is opening Friday a two-month period for the public to comment on the project.
The sea wall was originally built between 1893 and 1897, the Park Service said in a recent historical report. It is more than a mile and a half around, the report said.
“Despite various repairs over the decades since their original construction, the seawall systems are no longer structurally sound, and threaten the historic setting and visitor safety,” the Park Service said in a statement.
“Without improvements, the walls will continue to deteriorate and fail which will lead to walkways buckling and soil eroding,” the statement said.
Parts of the sea wall will be rebuilt on top of new, stronger foundations, and the walkways will be replaced.
The sinking section at the Jefferson Memorial was believed to have failed because it was built on a foundation of wooden pillars that were not long enough to reach bedrock. The old foundation was replaced with concrete pilings and caissons resting on bedrock.
Litterst said he thinks the same process would be used this time.
The Park Service said the sea wall repairs should also protect cherry trees from being killed by tidal saturation.
A contract to design and execute the project will be awarded next year or in early 2024, the Park Service said.