May 20, 2009
Dear Coalition Friends:
Now that Congress and Secretary of Interior Salazar are providing funds for repairs on the National Mall, the National Park Service is preparing to begin a priority project, repairing the sinking seawall at the Jefferson Memorial. NPS is considering several options, as outlined in the Park Service notice and the Washington Post article below, and is seeking comments on its Environmental Assessment for the project. See the link provided below.
Repairing the Mall's infrastructure is a critical need, so this is a good start. The Park Service is working on a Mall Plan to refurbish areas of the Mall under its jurisdiction. Still needed is a big-picture vision for the entire Mall in its third century -- what the National Coalition to Save Our Mall calls the "3rd Century Mall" -- that incorporates the interests of all constituencies including the Smithsonian, National Park Service, National Gallery of Art, District government, Capitol and White House, the public, and the nation's interest as a whole.
From the National Park Service:
Recently, the seawall located directly in front of the Thomas Jefferson Memorial has settled and separation and cracking of the pavement along the north plaza has increased, impacting visitor safety and interfering with the intended experience at the site. To improve conditions at the memorial, the National Park Service (NPS) is proposing to rebuild the seawall, resurface the north plaza, and improve transition areas between the plaza and surrounding areas. Implementing the repairs proposed by the NPS would result in negligible, long-term, beneficial impacts to water quality and floodplains; and moderate, long-term, beneficial impacts to cultural landscapes, historic structures, visual resources, visitor use and experience, and operations and infrastructure. The NPS has prepared an Environmental Assessment/Assessment of Effect that more fully describes the NPS preferred alternative and is the document that will be used for compliance with both the National Environmental Policy Act (NEPA) of 1969, as amended and the National Historic Preservation Act of 1966, as amended. This document has been posted to the NPS Planning, Environment and Public Comment (PEPC) website at http://parkplanning.nps.gov.
If you wish to review and comment on this Environmental Assessment/Assessment of Effect you may mail comments by May 29, 2009 to the address below or you may post them electronically on the PEPC website. Before including your address, phone number, email address, or other personal identifying information in your comment, you should be aware that your entire comment, including your personal identifying information, may be made publicly available at any time. For further information, please contact Perry Wheelock, Chief, Division of Resource Management at (202) 245-4711.
THE WASHINGTON POST
Michael E. Ruane
Washington Post Staff Writer
Wednesday, May 20, 2009
Almost from the day the Jefferson Memorial opened in 1943, its seawall and north plaza have been shifting atop the layers of unstable river mud on which the memorial is erected.
The 31,000-ton marble and limestone memorial itself appears to be standing firmly on the 11 rings of caissons and piles driven through the muck to the bedrock below.
But the seawall and north plaza, although they, too, are built on piles, have been sinking and sliding at an ever increasing, and alarming, rate away from the memorial and into the Tidal Basin. Cracks appear regularly in the plaza, threatening its structural integrity, and now have to be patched every three or four months.
The National Park Service is now pondering, and inviting public comment on, three major engineering projects designed to fix the problem. All three would take up to two years, and would constitute the most extensive work in decades on one of Washington's most beautiful landmarks.
Here are summaries of each plan.
- Alternative A would be to take no action.
- Alternative B is the park service's preferred approach.
The stones that cover the wall on its top and side would be removed and saved, and the old wall structure would be demolished. Caissons would be drilled like pillars through the mud to the bedrock below and a new wall would be built atop the caissons. To further anchor the wall, steel pipe piles filled with concrete would be drilled through the top of the wall at two different angles. The wall's "capstones" and "facing stones" would then be replaced. The work would hold the seawall and plaza in place, and the plaza would then be repaved to eliminate cracks.
- Alternative C envisions removing the surface of the north plaza. Angled pipe piles would be sunk to bedrock throughout the plaza. The plaza would be repaved. The seawall's facing and cap stones would be removed and saved. "Micropiles," made of one or more steel bars, would be drilled at two angles through the existing seawall, and the seawall stones would then be replaced.
- Alternative D is the most radical option. The plaza surface would be removed, and most of the soil underneath would be excavated and trucked away. It would be replaced with a "more binding" soil. The plaza would then be repaved. The seawall would be reinforced with micropiles, as in alernative C.
The public can read and comment on the repair plans at http://www.parkplanning.nps.gov/ through May 29.
Back to the top
| 
