Spanish architect Santiago Calatrava said his designs for the first phase of Denver International Airport’s south terminal redevelopment will complement the airport’s best-known architectural element — its terminal with the white-tented roof.

The DIA tent delivers an important image all over the world, Calatrava said, adding that he was conscious of preserving and protecting the airport’s existing architecture and view corridors as he designed the south terminal complex.

“We have given our best to create a dialogue between the two buildings in a complementary basis to respect the iconic view of the tent,” Calatrava said of the interplay between his structures and the existing terminal, which was designed by Denver architect Curt Fentress.

The south terminal project’s first phase, which is expected to cost as much as $650 million, includes a commuter-rail station, a public plaza that links with the existing terminal, and a 500-room Westin hotel.

Calatrava said the way the plaza’s canopy enters the area under the terminal tent “without touching it is a real declaration of respect” for Fentress’ design.

On Thursday, Fentress’ office said he had no comment at this time on Calatrava’s designs.

DIA manager Kim Day said the airport later will consider a second phase of the south terminal project, costing up to $250 million, that could include a reshuffling of existing functions in the terminal’s Great Hall, including a move of security checkpoints to new locations on the sixth level where airline ticket counters currently reside.

On Thursday, Calatrava met with local government and business leaders and he used pencil and water colors to sketch the inspiration for his designs.

“The tipping point for this project is having incredible functionality with great design,” said Denver Metro Convention & Visitors Bureau President Richard Scharf, after seeing Calatrava’s presentation.

Ever sensitive to the budget crisis gripping Denver and other local governments, DIA’s Day told the gathering that “no general fund money or city tax dollars will be used on this project.”

She said the airport will develop a plan of finance to pay for the project’s first phase and take it to the Denver City Council by early fall.

Airlines at DIA have expressed some concern in the past about possible excessive spending on capital projects by the airport that could drive up the carriers’ rates and charges.

“We assure the airlines that we will not do anything that negatively impacts our airline partners,” Day said.

After viewing Calatrava’s presentation, Southwest Airlines Properties Manager Steve Hubbell said, “We obviously are very concerned about the potential costs of these projects.”

“We need to have a better understanding of how this is going to impact the rates and charges,” Hubbell said, adding that DIA “is working with the airlines” to determine the project’s financial implications.

“They are being transparent; they are being collaborative,” Hubbell said of DIA officials.

Day said the south terminal project includes at least 100,000 square feet of retail and other concession space that — along with the hotel — will generate revenue and help offset the cost of the project.

Calatrava’s design calls for the hotel-train station-plaza complex to dominate the view of the terminal from the south, but those traveling to DIA will retain a view of the terminal tent through a low, saddle-like space between the hotel’s twin towers.

The south terminal project also includes a commuter-rail bridge over Peña Boulevard just east of the E-470 interchange that will accommodate the $1.2 billion East Corridor train from Union Station to the airport. Train service is expected to start in 2016.

An animation prepared by Calatrava’s firm shows the commuter-rail bridge as a graceful, cable-supported arc that will serve as a gateway for travelers driving to the airport.

DIA still must determine if it can afford the Calatrava-designed commuter-rail bridge.

The airport has proposed “enhancing” RTD’s design for the bridge and paying the difference between the “base price” the Regional Transportation District will budget for the bridge and what it would cost to build it according to Calatrava’s design.

RTD recently selected a consortium of private companies to build the East Corridor train under a public-private partnership.

On Aug. 12, RTD and the firms will be able to identify the amount of money they have for the rail bridge after they complete financial terms of the public-private partnership, said RTD spokeswoman Pauletta Tonilas.

DIA will have until Jan. 31 to decide whether it can afford to pay the difference between the base price for the bridge and the amount needed to realize Calatrava’s design, said Day, DIA’s manager. When an early Calatrava design came in around $60 million, airport officials said they could not afford that price.

The 59-year-old Calatrava, whose specializes in the design of bridges and train stations, is one of the most prolific engineer-architect-designers in the world.

He has designed the new World Trade Center transportation station in New York City where the twin trade towers stood before the 9/11 attacks.

He also has designed train stations in Liege, Belgium and Lyon, France, among other locations, and numerous bridges around the world, including spans in Buenos Aires; Jerusalem; Seville, Spain; and Orleans, France.

Jeffrey Leib: 303-954-1645 or jleib@denverpost.com