The long-delayed Gadsdenboro Park near the S.C. Aquarium - part of the largest vacant tract of land on the peninsula below Calhoun Street - will open by the end of the year. The Gadsdenboro Park area is close to the new site of the International African American Museum, which now is planned for a waterfront property on the Cooper River between the Charleston Maritime Center and Dockside Condominiums.

"Each will be good for the other," Charleston Mayor Joe Riley said of the two projects.

The 5-acre city park, formerly called Concord Park, is directly across from the maritime center. It sits at the center of a 10-acre parcel that is bordered by Calhoun, Concord, Laurens and Washington streets. Plans are in the works for mixed-use development for land along the north and south edges of the property.

The five-story Williams Terrace Senior Housing building, which will sit on the southwest corner of the property, will open in June 2015.

"It's really going to be beautiful," Riley said of the park. "It will be wrapped in trees."

The park will have soccer fields in the center, he said. It also will have walking paths around those fields and the outer edge of the park, playgrounds, game tables, a bocce court, adult swings, a fountain and public restrooms.

The land has a long history in the public realm, starting out as the site of public housing built in the 1940s. During Hurricane Hugo in 1989, the 162-unit Ansonborough Homes complex was severely hit by the storm and flood waters. A later analysis showed that the grounds were contaminated by an old coal gasification plant, and the homes were demolished in 1992.

The contamination was subsequently cleaned up, but the land has sat vacant for more than a decade.

The Housing Authority of the City of Charleston broke ground on the Williams Terrace Senior Housing in 2013. When finished, it will have 41, one-bedroom units, which will be available to seniors 65 and over who have annual incomes between $28,000 and $31,000. Rent is expected to be around $800 per month.

Mary Mims, capital fund manager for the Housing Authority, said people likely will be able to apply to rent the units through a private company. But no arrangements have yet been made for accepting applications.

Williams Terrace will be the second building completed on the property.

In 2011, a 63,000 square-foot office building was completed on the corner of Calhoun and Washington streets on the northern end of the property. It's the only building that has been completed on the on 10-acres so far.

Riley said the northeast and southeast corners of the property remain vacant.

A hotel was once contemplated for the northern end of the parcel, he said, but that plan no longer is in the works. Instead, some buildings containing office and residential space will be built there, but he's not sure specifically what those buildings will look like.

Market-rate housing is planned for the northeast corner, Riley said.

He thinks development of the site will move more quickly after the park is completed, he said.

Reach Diane Knich at 843-937-5491 or on Twitter at @dianeknich