WASHINGTON, D.C. (AP).- A nonprofit group that raises money for the National Mall is looking for ideas to overhaul three parts of "America's front yard" that have been overused and neglected for years. The Trust for the National Mall on Thursday started seeking proposals from architects and designers who will compete to make the mall one of the world's best parks.

Competitors must follow the National Park Service's plan for the mall developed over four years and signed in November by Interior Secretary Ken Salazar. At the time, he gave the mall a "C'' grade for its dead grass, stagnant water and sinking seawalls along its waterways.

Such competitions have been integral with the mall's evolution, from Robert Mills' white obelisk design for the Washington Monument to Maya Lin's concept for the Vietnam Veterans Memorial.

Bob Vogel, the mall's new superintendent, said organizers were looking to the "transformational changes" made by the Central Park Conservancy in New York, among other models.

"This is one of the earliest public spaces in our nation," he said. "There are facilities, some of them dating back to the 1800s, that really exceeded their life expectancy."

In May, Laura Bush joined the major effort to raise $350 million from corporations and donors to restore the mall. About $9 million has been raised so far.

Caroline Cunningham, president of the nonprofit National Mall group, said the $875,000 design competition would allow her to raise private funds for specific improvement projects.

"It's an exciting crossroads ... designing and creating for the next 100 years is very humbling and exciting for us," Cunningham said. "We plan to do it in a phased way so we're not raising $350 million tomorrow but over a period of time. I think it's very realistic."

The design competition will focus on three specific areas:

— For Union Square, at the foot of the Capitol, designers will be asked to create a new civic square in place of the Capitol Reflecting Pool to address the wear and tear caused by millions of visitors at protests, rallies, festivals and inaugurations. A specific space for crowds to gather could ease strain on nearby trees and grass, planners have said.

— On the Washington Monument grounds, designers will devise a new space to host performances, a food facility, restrooms and other visitor services.

— Farther toward the Lincoln Memorial at Constitution Gardens, planners hope to create a "pastoral setting" with reengineered, cleaner pools and perhaps a restaurant. Earlier plans for the mall imagined a restaurant there. But no eatery was built, and its pools often have green, smelly water.

Concepts from the finalists in the competition are slated to go on public view in April 2012, and the winners will be announced in May.

Donald Stastny, an architect hired to oversee the competition who also has managed design selections for the Oklahoma City and Flight 93 national memorials, said the mall presents complex design problems.

"We're looking for innovation. We're looking for sustainability," he said. "We're looking at setting the palette for the next 100 years of the mall."

The mall is a significant challenge, he said, because it's a civic space that must be flexible and handle 25 million visits a year, as well as provide enhanced security and infrastructure.

"But more importantly," he said, "how can we make these things beautiful?"

Copyright 2011 The Associated Press.