Crowds stroll the petal-lined perimeter of the National Mall's Tidal Basin in springtime Washington, D.C., for the National Cherry Blossom Festival. If they're paying attention to something other than the beautiful view, they might notice walkways overrun by flooding.
Although millions of people come to the Tidal Basin each year (the National Mall is the most visited national park in the country), the sea wall surrounding the basin has hardly been modified since it was constructed in 1882.
That's a problem, because near the Thomas Jefferson and George Mason memorials, the wall is sinking. At high tide, twice each day, 250 million gallons of water from the Potomac River enter the Tidal Basin through the inlet gates. The state of the sea wall is one reason, and rising water levels in the Potomac River exacerbate the problem. Starting about eight to 10 years ago, daily flooding has threatened the cherry trees' roots and engulfed walkways.
"Cherry trees are not particularly happy in this climate," said Teresa Durkin, senior vice president of the non-profit Trust for the National Mall, on a tour of the damage last week, "and we put them in bad conditions with the brackish water."
On April 3rd, the Trust for the National Mall and the National Trust for Historic Preservation announced a new three-year campaign called "Save the Tidal Basin" to address the site's problems in collaboration with the National Park Service. Fixing the Tidal Basin could cost as much as $500 million, the organizations estimate. The focus of the campaign will be the National Mall Tidal Basin Ideas Lab—architectural and landscape design firms will be invited to propose solutions to the Tidal Basin's challenges. The same day the campaign was announced, the National Trust named the site a "National Treasure."
The American Express Foundation is backing the Ideas Lab with a $750,000 grant. It will take about three years to develop the ideas to present to the public and for environmental review. Of course, the ideas would need funding to be realized.
In addition to the cherry trees, the area around the Tidal Basin hosts the Martin Luther King, Jr., Franklin D. Roosevelt, Thomas Jefferson, and George Mason memorials. "Current conditions do not do justice to a landscape of such significance," said Katherine Malone-France of the National Trust. Eventually, they might. In the meantime, the Park Service has been replacing cherry trees that are dying faster than usual due to flooding.
Warmer temperatures associated with climate change are also affecting the cherry blossoms: According to the U.S. Environmental Protection Agency, peak-bloom dates for the cherry trees have shifted earlier by approximately five days since 1921.