Waterford — A state proposal to open a 100-room, privately run lodge and public park at the site of the former Seaside sanatorium would have minimal environmental impact, according to a report commissioned by the Connecticut Department of Energy and Environmental Protection.

The lodge plan is one of three that the state outlined last year as possible futures for the long-vacant property. It would mimic state park lodges like the inn at Bear Mountain State Park in New York, reusing the historic buildings on the property for guest lodging and turning two other buildings on the site into private vacation cottages for larger groups and families.

That proposal would include some new structures on the waterfront, including converting an existing anti-erosion structure in the water into a fishing pier. The state would build a carry-in kayak launch and boardwalk, restore a seawall, and create or restore wet meadows, three tidal pools and an overlook.

It keep the property's four biggest buildings, the site of the former tuberculosis hospital designed by the renowned architect Cass Gilbert in the early 1930s, intact.

The DEEP-commissioned report by Massachusetts-based GZA GeoEnvironmental Inc. found that while the proposed landscaping, a parking lot and new building would cover some natural soil areas on the site, “there would be minimal impacts to soils.”

The restoration of a seawall on the waterfront and other landscaping plans in the lodge proposal could expand the habitats for some plant and animal species, according to the report.

“Not all of these habitats are likely to be native to the area prior to development,” the report says. “Some maintenance would be required on an annual and semi-annual basis to sustain these elements, including management of invasive species which are prevalent.”

Gov. Dannel P. Malloy announced in 2014 that Seaside would become a state park. Environmental impact evaluations like the GZA report must be conducted for certain projects involving state funding under the Connecticut Environmental Policy Act.

DEEP officials will host a public hearing on the report on Monday, July 31, at 7 p.m., at Town Hall. Comments on the report can be emailed to deep.seasideEIE@ct.gov before Aug. 11.

The document is available online at www.ct.gov/deep/seaside, and physical copies are available at the Town Clerk's Ofice in Town Hall, the Waterford Public Library, and at DEEP headquarters in Hartford.

GZA GeoEnvironmental compared the impact of the lodge proposal to three other proposed uses for the property: an ecological park with a nature trail, wildlife viewing areas and art installations; a passive recreation model featuring open lawns and tree groves and a hybrid plan that incorporates part of the lodge and the two park models.

The report assessed the environmental, noise and traffic impacts of all four possibilities and compared them to each other and to the impacts of leaving the property as is.

State officials have said they prefer the lodge option but are still developing environmental impact reports and accepting public comment on multiple possibilities. Most people at a public hearing in Waterford last summer spoke in opposition to the hotel proposal.

The GZA report identified several threatened or rare plant, bird and insect species that might live on or near the Seaside property, but found the proposed changes to the waterfront area would likely not have an adverse effect on their habitats.

The current lodge plan would include converting an area now covered in dune grass area to a "living shoreline" and seawall, the conversion of an existing forested and shrub-covered area to coastal woodland or meadow and converting an area that now has buildings and landscaping on it to a mix of coastal woodlands, meadow, grasslands, wet meadow and dunes.

None of these changes would likely affect the animals or plants living there, the report said. The proposed kayak launch could mean the loss of a tiger beetle habitat, it said.

All four assessed plans would have "minor, temporary" effects on air quality and noise pollution at the Seaside site during construction, the report said.

And while any development at the now-vacant property would bring more cars per day to the area, "the traffic impact from the increased vehicle trips is insignificant and no offsite improvements are proposed."

 m.shanahan@theday.com