Views of Lookout Mountain, a landscaped street leading to a new river plaza and at least one canoe/kayak launch are all part of a preliminary plan for a three-mile Riverwalk extension.

This week, representatives of Barge Waggoner Sumner & Cannon Inc. unveiled new site renderings for the latest section of the park to local officials. They are waiting on the state's green light to begin negotiating property rights for the new section, which will cost an estimated $15 million to complete.

County Engineer Todd Leamon said his office and the county's development arm recently applied for an additional grant that could take the path from Ross's Landing to as far as St. Elmo Avenue. The county already has funding to extend the Riverwalk to South Broad Street, he said.

The St. Elmo Avenue termination point will be about a half mile from the Lookout Mountain trail system, said John R. Brown, project manager with architect Barge, Waggoner.

"Ultimately, this would connect up to Lookout Mountain," he said. "There's going to have to be another half-mile section."

To support the three-mile extension, Alstom - which owns property along the proposed pathway - has been working to make way for the new walk, even discussing potential structural changes to one of its buildings, Brown said.

"One of the main reasons Alstom located here was because of the Riverwalk," he said.

Alstom spokesman Timothy Brown said the company is eager "to extend the Riverwalk to our property and give our employees and all of our neighbors access to those beautiful views."

Timothy Brown said the company is still negotiating with local officials to see what configuration makes the most sense with the current property layout.

"We're working with everybody to determine what the problem is and what the most logical solution [is]," he said.

Barge Waggoner Sumner & Cannon won the $1.14 million bid for the design phase of the project. Early plans include trailheads, public art and cultural markers.

Such markers might show Chattanooga's role in the Civil War, give a nod to the city's industrial past and lay out the history of various locations along the Riverwalk.

The path and building design and materials will match the rest of the Riverwalk, said Matthew S. Stovall, vice president of Barge Waggoner.