Courtesy of Gustafson Guthrie Nichol Ltd.

Redesign of Union Square at foot of Capitol Hill would include a new reflecting pool.

Three design teams have won competitions to reshape sections of one of the most prominent urban public spaces in the country: the National Mall in Washington, D.C.

The National Park Service says the 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 Mall’s lawns and aging infrastructure.

The nonprofit Trust for the National Mall on May 3 announced the winning teams. Each was selected over four other finalists for refurbishing a part of the Mall.

Rogers Marvel Architects, New York City, and PWP Landscape Architecture, Berkeley, Calif., will rehabilitate Constitution Gardens, which is located between the Washington Monument and the Lincoln Memorial, just east of the Vietnam Veterans Memorial.

The team of Gustafson Guthrie Nichol, Seattle, and Davis Brody Bond, New York City, was selected 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 were chosen to redesign the Washington Monument grounds. A key element of their proposal is a new amphitheatre with terraced seating.

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

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

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 of the financing for the two projects to be managed by the trust and the Park Service is to come from the private sector. Fund-raising already has begun.

Interior Secretary Ken Salazar said that the designs “are grand, respectful, sustainable and beautiful; in short, the are worthy to be a part of this important and iconic space.” Salazar added that he hoped the new designs would be in place in 2016, the Park Service’s centennial year.