Behnisch Architekten of Los Angeles and Germany

The team's proposed "Rivercircle" seeks to offer an equivalent to the National Mall in Washington with parks, promenades, performance stages and recreation encircling the river.

On the west side, Memorial Drive and Luther Ely Smith Park would be redesigned as a plaza connected to the Arch grounds by a lid over I-70.

The area would better link the Old Courthouse to the Arch and serve as a new entry point for a renovated, more child-friendly museum that would include a cafe with an outdoor terrace. New skylights in the museum would be directly below the Arch.

A reconfigured riverfront would become "River Balcony," running between the Eads and Poplar Street bridges. Thickets of trees would provide shade for gathering spots. The existing cobblestone shore would be removed in places and replaced with native vegetation. Promenades, plazas, gardens and markets would be built along the edges of the Arch grounds.

The "St. Louis Music Project" would anchor the park's north end, featuring a museum, studios, library, performance venue and other features focusing on the region's music.

At the south end, a sports park beneath the Poplar Street Bridge would include basketball courts, a skate park and climbing wall.

From the park, gondolas would glide on cables over the river and settle on the east side, in Illinois, near the "Bend" — an amphitheater embedded in the river's bank. The stage would float in the river and feature a 'sail-like" roof that could be dramatically lit.

Also on the east side, a new "Great Rivers Resource Center" would be housed in a circular building in a new American Bottoms Nature Reserve, part of an expanded national park.

An Eads Bridge with a restored timber deck would become a pedestrian-oriented span hosting festivals and other events.

— By Phillip O'Connor

Michael Van Valkenburgh Associates of New York

The team's philosophy is to celebrate the blurring of ecology with urban design, using landscaping to help make it happen.

The plan proposes demolishing the parking garage north of the Arch and replacing it with a garage on the south side of the grounds. The new garage would include an entertainment area on top, to be used as a skating rink in the winter and beer garden in the summer.

With the existing garage gone, the Arch grounds could be linked to Laclede's Landing with a "dynamic civic landscape." That would include an earthen amphitheater, playground, pathways, shaded seating and the "Gateway Urban Ecology Center," offering after-school programs and summer camps.

The team proposes a one-block-wide deck over I-70 and creating a new entrance off Memorial Drive into the museum. The deck would better link the Arch to the Old Courthouse and the rest of downtown.

The existing waterfront streetscape would be turned into a gently sloping cobblestone plaza between the Arch and the river that could host markets, concerts and other events. Sculptural river gauges would be built at the edge of the surface.

Throughout the grounds, more diverse plantings would enhance a new set of paths and turn the landscape "into a living laboratory of urban ecology."

On the Illinois side, a system of elevated walkways would allow visitors to observe restored wetlands. Also, water drawn from East St. Louis stormwater would be used to manufacture an urban habitat for birds.

The area would be supported by new National Park Service ornithological and hydrological research centers.

— Doug Moore

PWP Landscape Architecture, Foster + Partners, Civitas of Berkeley, Calif.

The team aimed for a design that would respect the original vision of Eero Saarinen and landscape architect Dan Kiley.

The team proposes a lid over I-70 and reconfiguring many downtown streets, including eliminating Memorial Drive north of Walnut Street.

Garages would be built under Kiener Plaza and Luther Ely Smith Park — 1,110 spaces in all. The existing garage north of the Arch would be replaced with a cultural center.

Expansive tree-lined walkways would frame the north and south sides of Gateway Mall as it extends from Citygarden into the Arch grounds.

The plan would "reopen the vista" from the Old Courthouse to the Arch by removing the berm initially put in place to screen the noise and view of I-70.

The tree-lined walkways on the grounds would be altered to provide more open views, while creating dense native woodlands and clearings along the banks of ponds. The park would also feature temporary art installations.

Small kiosks throughout, similar to those in New York City's Bryant Park, would provide coffee, light food and soft drinks as well as information about the park and city. Restrooms would be added.

The plan proposes rebuilding the Arch staircase and connecting the river to the park grounds with a grassy bluff that bridges the railroad. Riverboats would line the waterfront and provide food and entertainment.

The museum under the Arch would be expanded with visitors entering through a set of glass pavilions anchoring a new western entrance. Skylights would provide views of the Arch.

On the east bank of the river, a 65-foot-tall earthen mound would be built, along with agricultural fields and greenhouses. The additions would be part of an agricultural center to bring together international leaders of plant and life sciences and create research gardens.

The new mound would offer spectacular views of the Arch and the city skyline. A water taxi would shuttle passengers across the river.

— Doug Moore

SOM, Hargreaves, BIG of Chicago

Except for some new seating and pathways, improving the ponds and correcting some drainage problems, the proposal mostly calls for preserving much of the original park landscape. Many of the changes instead focus on the edges of the Arch grounds. The highlights include:

• Adding a visitor pavilion at the north end of the park and a learning center at the south end.

• Laying a "magic carpet" lid over the blocks-long section of Interstate 70, linking the Arch grounds to downtown and creating a civic plaza. At each end, the carpet would curve up, creating a gently sloping overhang under which cafes and kiosks could open.

• Keeping Memorial Drive open to north-south traffic, but a lane in each direction would be eliminated and traffic slowed.

• Adding new or improved sidewalks to several downtown streets and opening several to two-way traffic. The MacArthur and Eads bridges would be renovated to handle pedestrian and bike traffic. Vehicle traffic on the Eads bridge would be cut to two lanes.

• Turning Kiener Plaza into a civic square with a cafe, gardens, fountains and other amenities under a sculptural leaf canopy. Chestnut and Market streets would be narrowed to allow for expanded sidewalks. The Old Courthouse would be renovated and its historic exhibits expanded.

• Expanding the Arch's current underground museum and building a west-facing main entrance.

• Building a tree-shaded promenade and terraced gardens along Leonor K. Sullivan Boulevard on the river's west bank. A floating pavilion would be built along the river complete with a public pool that uses filtered river water.

• Lighting the river bridges and running a ferry so people can cross the river. On the east bank, in Illinois, a new pedestrian bridge would link a ferry landing over rail lines and a levee to an 11,000-seat amphitheater and a farmers market.

— Phillip O'Connor

Weiss/Manfredi of New York

Dubbed the "Full Circle," the plan would connect the banks of the river in three ways: a new pedestrian-and-bicycle pathway on the north side of the Poplar Street Bridge, a similar path using two of the traffic lanes across the Eads Bridge, and a ferry from a new landing on the St. Louis side to the East St. Louis bank.

Linking the two bridges with pathways on both sides of the river completes the circle.

The team envisions eliminating traffic through Memorial Drive along the Arch grounds and building a lid across the I-70 depressed lanes. The cover would be a wide, grassy pathway to the Arch grounds.

The path would slope downhill to a glass-filled entrance to an expanded underground museum, which would feature a view of the river through a glass wall embedded into the main staircase to Leonor K. Sullivan Boulevard.

On the south end, the plan calls for a large amphitheater, a miniature-golf course, a climbing wall and a skateboard park.

On the north end, the top floor of the existing parking garage would be used for food vendors, perhaps a skating rink, and would be covered with clear canopies. Parking remains on the lower levels, although wide staircases built into the garage would take pedestrians to and from Laclede's Landing, on the other side of the Eads Bridge.

Along the river itself, the plan calls for building terraced structures atop the east walkway of Sullivan Boulevard. A small harbor for the ferry would be built into the terraces.

On the east side, the plan would create a meandering waterway with restored wetlands, other greenery and walking and biking paths. The area would have a new cultural and ecological center.

A dramatic addition would be a new, bigger elevated walkway to extend the new overlook at Malcolm Martin Park to the river's edge.

— Tim O'Neil