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Braintree-based Flatley Co. is the latest developer to gauge demand for real estate growth in Charlestown with plans to redevelop a 20-acre site on the Mystic River.

The developer is focusing on the former Domino Sugar warehouse at 425 Medford St. for a mixed-use project that would connect by a three-quarter-mile harborwalk to its Schrafft City Center office building in Sullivan Square. The development would total 1.7 million square feet, according to a Boston Globe report.

In a notification letter to the Boston Planning and Development Agency, Flatley CEO John Roche focused upon public realm and resiliency improvements that will be tied to the project.

Flatley Co. began designs reconnecting the properties to the Mystic River waterfront in 2014 when it hired Boston-based CBT Architects to redesign the Schrafft City Center’s pier, along with building common area updates.

Now it’s planning a larger waterfront resiliency and activation project that would include a three-quarter-mile extension of the harborwalk while raising the flood barrier elevation to 22 feet. New waterfront facilities will include recreation areas, a public dock, boat and kayak ramps and observation areas, the company said, reserving more than half of the site as public open space. The property currently includes approximately 6 acres used for industrial marine purposes and a 181,379-square-foot warehouse.

Flatley Co. will seek approval under a planned development area review, and construction would start with the flood barrier. The company bought the Domino Sugar site in 1993, five years after the refinery closed.

The company’s announcement comes on the heels of three major development plans for the western side of the neighborhood.

Developers RISE Together and TRAX filed initial plans last week for a 2.6 million-square-foot commercial and multifamily development on a series of parcels on both sides of Interstate 93, including an initial phase of development on Cambridge Street just west of Sullivan Square.

Fulcrum Global Investors of Newton proposes a 29-story apartment tower at One Medford St., Related Beal is seeking to redevelop a self-storage facility as R&D space and owners of Hood Business Park are continuing a master planned expansion of the 20-acre property.