Mohegan — Preston residents and regional leaders got their first looks Tuesday at poster boards with renderings of the proposed $200 million to $600 million development plans by  the Mohegan Tribal Gaming Authority for the former Norwich Hospital property in Preston.

Renderings of the plan were propped against closed curtains in the Royal Suite on the 35th floor of the Sky Tower Hotel on Tuesday, and when tribal, state and Preston leaders were finished at the podium, the curtains were opened to reveal the land across the Thames River where the project is envisioned. The 393-acre former state mental illness institution has sat vacant since 1996, its buildings decaying and collapsing.

The two poster boards on display show a marina at the river’s edge, timeshare units overlooking the river and Mohegan Sun across the river, hotels and retail space also on the land that was the main campus of the former Norwich Hospital. To the east of Route 12, where the property slopes up to large wooded tracts, an outdoor adventure park, an indoor water park, a large theme park of about 40 acres and a “snowflex” synthetic ski area would occupy the high ridge, with a “glamping” — glamour camping — facility to the north, at the Norwich border.

A public park along the Thames River would provide public access to the waterfront area, although active freight rail tracks cut off much of the riverfront. An approved rail crossing remains intact in one spot.

Not shown but also envisioned is a ferry that would carry patrons across the Thames River to Mohegan Sun, said Paul Tresnan, director of program management for the gaming authority.

The project could turn the region into a "destination," officials said Tuesday.

The renderings show the plan to preserve the oldest former hospital structure, the so-called Administration Building the town has left standing in the hopes of seeing it refurbished. The existing adjacent historical Jewish cemeteries also would be protected and buffered from development, tribal planners said Tuesday.

And the two sites where two World War II fighter planes crashed in a training flight in the wooded eastern hill of the property also would be preserved, perhaps with a memorial.

During a Tuesday evening presentation for the Planning and Zoning Commission and about 40 residents and town officials, Tresnan said the tribal authority plans to retain ownership of the property, while soliciting development proposals for its major components, including a large entertainment retailer, such as Bass Pro Shops or Cabela's, hotels, and more specialized developments. Tresnan said a group that works with the tribe's Pennsylvania property develops year-round synthetic skiing venues.

"Are you planning some sort of gondola going across the river?" resident Mike Clancy asked during public comment period Tuesday evening.

"That's a good idea," Tresnan responded. He added that the tribal authority definitely wants a connection across the river by ferry or water shuttle.

Tresnan said a rough schedule would have tribal and town leaders completing approvals of the Property Disposition and Development Agreement in the coming weeks. Public informational meetings tentatively are scheduled for Feb. 2 and 4, with a town meeting on Feb. 9 and referendum tentatively planned for Feb. 21.

If the plan is approved, the town and tribe would sign the agreement, releasing $10 million in state bond money pledged by Gov. Dannel P. Malloy on Tuesday to complete the environmental cleanup of the property. The tribe would take over ownership of the property once the cleanup, estimated to take about a year, is completed.

Tresnan anticipated filing formal development plans with the Planning and Zoning Commission shortly after signing the purchase agreement. Commission Chairman Art Moran, who viewed the conceptual plans during a closed-door meeting with the Preston Redevelopment Agency a few weeks ago, said some "tweaking" of existing zoning regulations for the former hospital property could be needed for some aspects of the plan. For example, while camping would be allowed, RV parks fall under different regulations.

The memorandum of understanding the town and tribe signed last May called for all development to be completed within five years, or by 2023, Tresnan said.

During the afternoon new conference, Tribal Chairman Kevin Brown said it has taken decades of planning and work to reach the point where the tribe and town are nearing completion of the property agreement, nine months after the deal was announced in May.

Once the agreement is signed, Brown said, Mohegan tribal planners will court a variety of private developers to fill in the marks on the map designated for specific developments. Brown estimated the first shovel of construction won’t hit the ground until about 2020, while Tresnan hoped for an early start in 2018.

Tuesday afternoon's news conference was held in a top floor Sky Hotel luxury suite packed with reporters, municipal leaders and state legislators from throughout the region and tribal officials.

Getting to the point where the 393-acre former hospital property is ready for development required a strong, cooperative working relationship of Preston town officials, state and federal agencies and the Mohegan tribe, all of whom were represented in Tuesday’s hourlong news conference to unveil the conceptual plans.

Malloy, quoting Winston Churchill, called Tuesday’s step in the process “the end of the beginning” for the redevelopment effort. Malloy said the state had the responsibility to support Preston in the cleanup effort, calling it unfair to leave the burden on the small town and its surrounding region.

“What the state did was, honestly, unfair to this part of the state,” Malloy said. “Government should not treat its municipalities, its partners, this way.”

Malloy said the state Bond Commission will vote to approve appropriating the final $10 million needed to finish demolishing decaying buildings, removing contaminated debris and soil and preparing the land for development.

Since the town agreed to take over ownership of the former hospital property in 2009, with its dozens of abandoned, decaying buildings, town agencies have obtained about $15 million in state and federal grants to clean up the property, and used about $1.5 million in scrap metal value to offset further cleanup costs, Preston Redevelopment Agency Chairman Sean Nugent said.

Malloy said the state has invested more than $9 million in the cleanup to date.

U.S. Rep. Joe Courtney, D-2nd District, said Preston also has received the largest concentration of federal Environmental Protection Agency brownfields cleanup funds in the New England region, at $2.1 million.

Courtney, Malloy and Brown credited the persistence of Preston leaders, especially 21-year First Selectman Robert Congdon and Nugent with the success of the cleanup and ultimately the development plans.

“Bob’s persistence, Sean Nugent and the PRA, is really the reason we are here today,” Brown said.

Congdon in turn, credited Malloy for taking on the responsibility of the cleanup, saying he was the first governor of Congdon’s tenure to visit the property and see the problems firsthand. And he expressed confidence that the Mohegan tribe would develop the property in the right way.

“The Mohegan tribe has been the fabric of the region long before Europeans got here,” Congdon said.

The entire proposed development project has the potential to double the town’s current tax base of $387 million, Congdon said. He acknowledged that with the economic growth would come greater expenses, and town officials currently are studying how the need for police, fire protection and ambulance services will change in the future.

c.bessette@theday.com