Three design teams have won a high-profile competition to revamp and rehabilitate sections of the National Mall in Washington, D.C. The National Park Service says upgrades are needed because the millions of annual visitors and hundreds of rallies, concerts and other public events have taken their toll on the 684-acre National Mall's lawns and aging infrastructure.

The non-profit Trust for the National Mall announced the winners on May 3. A team of Rogers Marvel Architects, New York City, and PWP Landscape Architecture, Berkeley, Calif., will rehabilitate Constitution Gardens, located just east of the Vietnam Veterans Memorial.

The team of Gustafson Guthrie Nichol, Seattle, and Davis Brody Bond, New York City, has been picked to work on Union Square, which lies at the foot of Capitol Hill and west of the U.S. Capitol. The firms' plan includes a new reflecting pool with diagonal, paved paths across it.

OLIN, Philadelphia, and New York City-based Weiss/Manfredi have been chosen to redesign the Washington Monument's grounds. Their proposal includes a new amphitheater with terraced seating.

Each of the three winning teams was picked from among five finalists for each portion of the National Mall.

The cost of the three projects has not yet been determined. However, a more sweeping 2010 National Park Service plan for the Mall had estimated costs ranging from $606 million to $705 million, including about $260 million to $316 million to deal with deferred maintenance.

The redesigns do not involve work on the Smithsonian Institution's museums or national monuments, such as the Lincoln and Jefferson memorials and the Washington Monument.

The Trust for the National Mall and the park service will be in charge of the Constitution Gardens and Washington Monument-area projects; the Architect of the Capitol will oversee the Union Square redesign. About half the financing for the two Trust for the National Mall-National Park Service projects is to come from the private sector. Other funding would come from congressional appropriations.