PORTLAND, Maine — Mercy Hospital has taken initial steps for a major expansion along the Fore River that will end the hospital’s presence downtown by 2018.

The hospital is seeking to amend a conditional zone agreement reached with the city in 2001 that paved the way for it to build on the Fore River Parkway in 2008. No specific language was proposed when the zoning agreement was discussed at an Aug. 26 Planning Board workshop.

Hospital spokeswoman Susan Corliss said there is “no definitive master plan” in place, but confirmed Tuesday the hospital would like to celebrate its centennial in 2018 by fully relocating to the Fore River Parkway from 144 State St.

Conceptual plans of the Fore River Parkway expansion, presented by Steve Bushey of the South Portland office of Fay, Spofford & Thorndike, call for a 250,000-square-foot addition to the 138,000-square-foot hospital completed in 2008, and a 72,000-square-foot ambulatory care center.

The expansion could require paving wetlands adjacent to the current hospital space at 175 Fore River Parkway. Permits for filling in the 3.5-acre pond and wetlands were granted by the Maine Department of Environmental Protection and U.S Army Corps of Engineers in 2013.

A storm-water management plan was approved by the DEP as part of its comprehensive site review.

Filling in the wetlands is unavoidable, according to a 126-page application filed by Bushey.

He said it “poses a significant constraint and, therefore, an enormous challenge for the Phase 2 expansion. Building Phase 2 of the Hospital to the south of the wetland is not an option.”

A second phase of expansion has been anticipated since the hospital filed a master plan with the city in 2006. However, the latest plan depicts a much more ambitious project, and holds the possibility of two more medical office buildings on the site, as well as parking garages.

The hospital already has a medical office building at 195 Fore River Parkway.

Bushey said the need to fully consolidate hospital operations is a matter of convenience, safety and economics.

“The inefficiency and inconvenience of a dual-facility campus costs Mercy $9.5 million per year to maintain and results in on-going yearly financial loss,” he said, adding the hospital expansion must be connected to the existing Fore River Parkway building for the same reasons.

“Similar losses would be sustained in a divided Fore River campus because of busing requirements and duplication of operations such as imaging, laboratories, food services, cafeteria, security, plant engineering, and environmental services,” he said.

Mercy’s Fore River Campus was constructed on a former gravel pit and on land used for other railroad and industrial purposes. The wetland area is in the former gravel pit.

“The pit wetland area was improved during the Phase 1 construction. These improvements include a substantial cleanup of solid waste including tires, white goods, garbage and related debris that had been deposited or collected in the pit area,” Bushey said.

Mercy’s ownership has changed since the Fore River Campus opened. The hospital is part of the Mercy Health System, which was bought from Catholic Health East last October by Brewer-based Eastern Maine Healthcare Systems.

The certificate of need required for Maine Department of Health and Human Services approval of the sale showed EMHS was ready to assume $73 million in Mercy debt and spend $115 million over five years “for a range of purposes, including to consolidate operations at the Fore River Campus, improve operating performance, develop required care models for success under health care reform and finance integration of Mercy into EMHS.”

EMHS spokeswoman Suzanne Spruce declined comment on the expansion, except to say there is no master plan in place. She added EMHS will need approval of a new certificate of need by DHHS for any expansion to move forward.

An Aug. 22 memo from City Planner Jean Fraser indicated the amendment request could go through additional workshops to determine if and how the conditional zoning agreement may be amended, whether any amendments would require City Council approval, and the elements of the revised hospital expansion master plan.

Citing a goal to have two more phases of expansion completed within two to six years, Bushey indicated the hospital wants to move sooner rather than later.

“The need to complete the move to the Fore River Campus is now front and center on Mercy’s agenda, and the hospital finds itself in an untenable situation,” he said in the hospital’s application.