A plan to create a trail and public space along the Delaware took a big step forward Thursday with the transfer of four piers and five vacant acres to the Delaware River Waterfront Corp., a nonprofit organization that acts as a steward of development on the river.

The transaction includes a strip of riverfront land next to a Wal-Mart store on South Columbus Boulevard in South Philadelphia; Piers 64, 67, 68 and 70; and 11 acres of submerged land between the piers.

The DRWC was able to acquire the property through a deal involving the Natural Lands Trust, a nonprofit group committed to land conservation.

The trust received a $1.25 million grant from the Pennsylvania Department of Conservation and Natural Resources and used it to buy the land at reduced rates on behalf of the DRWC.

Tom Corcoran, DRWC president, said the property was valued at $2.5 million, but the owners - Delaware Associates L.P. - agreed to sell it for half the price, with the difference representing a charitable donation to the trust. Delaware Associates is a partnership that includes principals with the Pennsylvania Real Estate Investment Trust Inc.

"This is a milestone event for us," Corcoran said. "It represents the first acquisition in the creation of a future trail system that runs the entire length of the Delaware River."

The DRWC already owns Pier 53 and has created a small park at the foot of the pier. Next, it will create public access to the pier via a boardwalk or pathway.

The goal, Corcoran said, is to develop a wetlands park that stretches along the water's edge from Pier 53 at Washington Avenue to Pier 70 at Mifflin Street.

With the Natural Lands Trust deal, the DRWC now controls about a third of the land it needs. But to build a 50-foot-wide trail along that stretch of waterfront, the nonprofit needs to secure more land from two owners: the Sheet Metal Workers Local Union 19, which has its offices at 1301 S. Columbus Ave., and a partnership that owns the proposed Foxwoods Casino site, between Tasker and McKean on South Columbus.

Corcoran said the Foxwoods property was tied up in litigation. The DRWC, however, has had "preliminary discussions" with the Sheet Metal Workers union about gaining public access to its waterfront land.

"Our intent is to acquire a permanent easement or simple ownership for all the land to create a waterfront trail and wetlands," Corcoran said.

Alan Greenberger, deputy mayor for economic development, said the recent deal was "integral" to implementing a proposed new master plan for the central Delaware River.

Molly Morrison, president of Natural Lands Trust, said that 60 years ago, her organization worked to protect a different section of land along the Delaware - now the John Heinz National Wildlife Refuge.

"This project represents a return to the city for us in our land-protection work and, as such, has special meaning," Morrison said.

"This piece of land is not much to look at," Morrison said, "but the opportunity to do something special there is what everyone envisions."

Contact Jennifer Lin at 215-854-5659 or jlin@phillynews.com, or follow on Twitter @j_linq.