Some people hissed in January when landscape architect Ken Smith won the competition to design the future Orange County Great Park. The 1,347-acre portion of the former Marine Corps Air Station El Toro in south Orange County was a covetable plum if ever there was one.

In the world of landscape design, the selection of Smith was an event on the scale of an upset at the Olympic Games. Smith is best known for small parks in New York, particularly a tony rooftop garden in the newly renovated Museum of Modern Art in Manhattan. For the Orange County job, Smith assembled a team of designers, including Mexican architect Enrique Norten, Los Angeles-based landscape designer Mia Lehrer & Associates and artist Mimi Smith.

How, then, did this small-time interloper win the El Toro competition over such titans of turf as Laurie Olin, likely the busiest and best-known landscape architect in the country, and Hargreaves Associates, which designed the fine, three-mile-long Guadalupe River Park in San Jose?

Even the normally good-natured Christopher Hawthorne, architecture critic of the Los Angeles Times, was snarking about the owlish New Yorker. "Is Ken Smith capable of executing a project of this expense, complexity and sheer size?" he asked, sounding unconvinced.

The "more vexing question," Hawthorne went on to write, "frankly, is whether Smith's final scheme will be up to the task strictly from a design point of view."

Well, that is the critical question on this and any other design. Still, I think Smith's scheme, as it stands, is an inspired beginning. True, the current plan offers a limited amount of information, and we will not really know how successful it will be until it is built. That said, I think the Great Park has a better-than-even chance of becoming a memorable set of trails, views, habitats and, above all, experiences.

One thing that inspires confidence in Smith's park scheme is simplicity. While the site is "flat, featureless and uncomfortable," as the architect told reporters last month, it does have some streams and remnants of wetlands. Out of these vestigial elements, Smith has fashioned essentially three organizing events: a "great canyon" along the east, a wetlands area along the west, and a central area that finds use of the old runways, including a through-road and an aviation museum.

The canyon accomplishes the most difficult and important task of all, which is to provide a unifying element that ties the park together. A linear trail along a continuous landscape feature is a simple idea. The exciting part is the way that Smith has enriched this simple idea: Like a natural canyon, the artificial canyon is constantly changing in width, depth and profile. The canyon is a way of relieving the tarmac-like flatness of the former El Toro.

Significantly, Smith's drawings show different cross-sections of the canyon at different points. The canyon is a condition in constant change, offering a variety of experiences along the way. The canyon terminates at the south in what the designers call a "lake feature."

The wetlands is a little hard to decipher from the map. Wetlands are fragile environments, so I assume that Smith and his team will create wooden boardwalks that stand clear of the spongy soil, or some other way that allows people to go swamp crawling without destroying habitat.

I wonder if this proposal excites Orange County residents; if not, it should. I have seen three wetlands parks — one in McGrath State Beach in Ventura County, another in Sherman Oaks at Sepulveda Dam and a third at a natural history museum in Aspen, Colorado — all of which are successful. Much of the interest of a wetlands comes from the life it attracts—the ducks, frogs, pelicans and other fauna that seem to appear from nowhere. The proposed wetlands in the Great Park will be large enough to make visitors feel immersed in the experience. And it could provide habitat of real value to migratory waterfowl, who have been left with very little in Southern California, Bolsa Chica and Playa Vista notwithstanding.

The proposal has its share of "programmed" spaces, such as the aviation museum and an amphitheater. It is currently a popular doctrine that parks need programming to attract loads of people, and some park designers, especially in urban settings, can get pretty manic with programming. Here the programming seems kept to a tolerable level—enough to sell the project to people who believe that programming is civic minded and makes the park more attractive to "constituencies." Happily, there are no "exploration" forests or "discovery" gardens to make our children go goggle-eyed.

When completed, the Great Park will conclude years of controversy regarding the reuse of the former military base. When the last marine left El Toro in 1999, the official reuse plan called for development of a large, civilian airport. However, leaders of nearby cities, especially Irvine, resisted the proposed airport, and led two successful ballot measures to block the project.

Since then, Irvine has taken control of El Toro, designating roughly half of the 4,700-acre site for wildlife habitat, parks and civic uses, including the Great Park. Lennar, a homebuilder, paid $650 million for 3,718 acres, donating about 1,500 acres to the city, including the park land, as a precondition of development.

Park construction is scheduled to start this spring, although the park as envisioned may take a while to arrive. Like many other military bases, El Toro sits uneasily on ground steeped in carcinogens and other hazardous materials. The Pentagon plans to spend at least $300 million to clean up the toxic stew. Park development is expected to cost $400 million.

Of course, details are everything, and the park must be well-designed at human scale, as well as at the 30,000-foot viewpoint of this site plan. But at least the park has a strong scheme to start with. A strong scheme by itself will not make a great park, but it's far easier to make a great park with a strong scheme than without one.

As for the charge of Smith's inexperience, it may be meaningful, or may just be a canard. Mia Lehrer, a consultant on the project, observed that Frederick Olmstead won the job of designing New York's Central Park fairly early in his career, when he had few projects to his name.

"The last I heard," she said dryly, "people were still enjoying that park pretty well."