It was modeled after the grand canals at Versailles and Fontainebleau, created to enhance two presidential monuments, and designed to invite repose amid Washington's most famous landscape.

Since then, it's been skated on, fished in and waded through. Civil rights marchers cooled their weary feet in it. War protesters skinny-dipped in it. A man bent on suicide once drove a truck into it, although it's less than a yard deep.

The Lincoln Memorial Reflecting Pool, which for generations has mirrored the national face of protest and celebration, is now often foul and unsightly. And eight decades after its construction, the famed landmark is finally being replaced.

The project is one of several underway that together make up a multimillion-dollar overhaul, with substantial federal funding, that aims to spruce up the Mall and burnish the city's monumental core after years of neglect and overuse.

"I remember . . . being on the Mall and seeing how downtrodden it was, and how beat up the turf was and how dirty the reflecting pool was," Interior Secretary Ken Salazar, who can see the Mall from his office windows, said last week.

Now, he said, "I see a lot of visible projects that demonstrate significant progress."

The Interior Department oversees the National Park Service, which is responsible for the Mall and its environs.

Work has also begun on the repair of the Mall's 1931 D.C. War Memorial and the National Park Service's century-old Sherman equestrian statue, outside the Treasury building.

And it continues on the Jefferson Memorial sea wall and the new Martin Luther King Jr. Memorial, both on the Tidal Basin.

The projects, for now, have large portions of the "nation's front yard" dug up, sealed off behind chain-link fences and wooden barriers, and populated with construction trailers and work cranes.

Fenced in and nearly dry

The 18-month, $30.7 million project on the historic reflecting pool project began in November.

The 2,128-foot-long pool is fenced off and has been emptied of most of its 6.5 million gallons of water. A walkway on its south side remains open to the public.

After the old basin is ripped out, 2,100 pine or fir pilings will be pounded through the soft earth to bedrock and a new basin will be installed on top.

The pool dates from shortly after 1922, when the Lincoln Memorial was dedicated before a crowd that included Abraham Lincoln's only surviving son, Robert, who was then 78.

It became an immediate gathering place - in winter, hosting thousands of ice skaters, in summer, model boat regattas and fishing tackle exhibitions.

During World War II, temporary pedestrian bridges were built across the pool to connect buildings alongside it. In August 1963, civil rights marchers dangled their feet in the pool as King delivered his famous "I Have a Dream" speech at the Lincoln Memorial.

In 1970, war protesters marched through the pool in a face-off with riot police. And in 2009, it was rimmed with people at a pre-inauguration salute to Barack Obama.

But as early as 1927, a visitor wrote of its "disgraceful" condition. Cleaning became necessary two or three times a year - each one netting 10 to 15 truckloads of debris, according to the park service.

No more tap water

The pool's floor was built of an asphalt-covered membrane, slate and concrete tile, according to park service documents. It was not supported by pilings, although its stone perimeter was, said Stephen Lorenzetti, deputy superintendent of the National Park Service's National Mall & Memorial Parks.

Because much of the Mall is on soft reclaimed land dredged from the Potomac River, the pool began to sink - and leak. The park service estimates that leakage and evaporation cost the pool nearly 500,000 gallons of water a week.

A concrete slab foundation was added to the pool in 1929, and in the 1980s another concrete bottom was poured over the old one. But the sinking and and leakage continued. And in 1986, an engineering report said the pool's structural system was failing.

Now the old bottom will be replaced with an 8-inch-thick, 375,000-square-foot layer of new concrete supported by timber pilings, according to Dennis M. Quinn, a park service project specialist. The new pool will hold about 2 million gallons water less than the old one.

The pool's water system will be replaced, too. In the past, it has been filled with city tap water, which quickly became stagnant and soiled.

The new system will utilize water from the Tidal Basin, which will be recirculated, cleansed and replenished from a nearby underground storage tank, Quinn said.

The project will also create sidewalks along the edges of the pool, where visitors have worn 15-foot-wide dirt paths. And it will complete the security system on the east side of the Lincoln Memorial.

A missing element

Meanwhile, work has started on the elegant D.C. War Memorial - the domed and columned marble-and-limestone monument to the District's World War I veterans just west of the World War II Memorial.

Dingy, overgrown and neglected, the World War I edifice, dedicated on Armistice Day in 1931, is being cleaned and re-landscaped. Its drainage system is also being repaired. Total cost: about $2.6 million.

The National Park Service is also searching for information about the large metal medallion that once decorated the memorial. It vanished years ago, officials said, and only a drawing remains.

Work has also just started on the $2 million repair of the century-old - slightly cursed - equestrian monument to Gen. William Tecumseh Sherman, south of the Treasury building on Pennsylvania Avenue. The towering 1903 monument, whose designer died during construction and a model for two of the sculptural elements was later murdered, will have its bronze statues and surrounding stonework redone.

The $12 million, 19-month project to fix the sinking Tidal Basin sea wall at the Jefferson Memorial is nearing completion, scheduled for June. And the $120 million memorial to King is to be dedicated in August.

The King memorial has been funded mostly with private money. And the reflecting pool and the Jefferson memorial efforts are funded by government stimulus money through the American Recovery and Reinvestment Act, officials said.

But there remains an estimated $400 million in deferred maintenance on the Mall, experts have said.

Last fall, Salazar gave the Mall an overall grade of C.

Last week, he said: "I'm very proud of the Mall. I think most Americans who come here are inspired. . . . It is a great place, but we still have more work to do."