The site of the the 11th Street Bridge Park in Washington. (Jeffrey MacMillan)

When the 11th Street Bridge Park opens in 2019, an abandoned freeway bridge will have been transformed into Washington's first aerial park, connecting the east and west sides of the Anacostia River with recreational open space that will span the length of three football fields.

The $45 million project will link two vastly different neighborhoods. On the west will be the thriving area of Navy Yard, with Capitol Hill just a little farther north. On the east will lie an area that has been largely left out of the city’s economic boom and continues to experience high rates of poverty and unemployment.

The project's architects envision residents from across the city converging on what they hope will be a world-class civic space with amenities including an amphitheater, community farm, hammock grove and art installations. But they also fear that the park will spur a big jump in adjacent property values, potentially pricing out residents east of the river.

"It's one of the biggest questions of our time: How do you invest in places of need without displacing the people you're trying to serve?" said Scott Kratz, director of the project, which is a collaboration between the D.C. government and the local nonprofit Building Bridges Across the River.

The answer Kratz and his collaborators have turned to is one that is being adopted by cities across the country as they grapple with the need to preserve affordable housing and retain longtime residents in the midst of gentrification.

The 11th Street Bridge Park project will establish Anacostia's first community land trust, a nonprofit organization that acquires property using private and public funds to create permanently affordable housing in an area with escalating property values. The goal is ultimately to build a portfolio of $5 million to $10 million in parcels of land east of the river within a one-mile radius of the bridge park, he added.

According to City First Enterprises, a nonprofit community development loan fund that the bridge park project has partnered with to spearhead the land trust, $10 million could create roughly 70 community land trust rental units affordable to people making 50 percent or less of the area median income.

Already, a nonprofit group has conditionally offered two parcels to the trust.

The land trust could help the city avoid the negative fallout of a similar project in New York, the project’s organizers said. Built atop a blighted elevated rail line in the Meatpacking District, the 1.5-mile High Line park has been a runaway success by many counts, but it also set off rapid gentrification in its surrounding areas, displacing many residents and businesses and transforming the neighborhood into one of the city’s priciest.

Across the nation, the land trust movement is gathering steam.

New York City's Department of Housing Preservation and Development announced in July that it would distribute a $1.65 million grant to develop and expand community land trusts, giving the movement a major boost and public stamp of approval.

In Baltimore — which has two operating land trusts, according to the Baltimore Housing Roundtable — Mayor Catherine Pugh (D) has voiced support for community land trusts, and activists are pushing for more funding to finance them. And in Pittsburgh, the city broke ground on its first community land trust in June.

The land trust model traces its roots to 1969, when a group of civil rights activists established the United States' first community land trust in southern Georgia. Today, there are over 300 community land trusts across the country, according to the National Community Land Trust Network.

Because it is often difficult to build a land trust from scratch, City First Enterprises is initially incubating the Anacostia land trust, providing the necessary resources and credibility and laying the groundwork for the trust’s eventual spinning-off as a separate independent nonprofit entity.

Meanwhile, the bridge park project and City First Enterprises are working to ensure that the land trust formation process is as transparent as possible. An advisory committee made up of residents, neighborhood organizations, real estate experts, government representatives and stakeholders from the bridge park project meet regularly to steer the development of the land trust.

This month, the land trust took its first steps toward formally launching. Mi Casa, a nonprofit affordable housing developer that is partnering with the bridge park project on the land trust initiative, purchased two vacant corner lots in the heart of historic Anacostia that had been held by the D.C. Department of Housing and Community Development. Talks are underway to facilitate the transition of these two lots from Mi Casa to the land trust, said Eugene Kim, development and communications manager for City First Enterprises.

Such partnerships with nonprofit developers are one way the trust can acquire land. It can also directly purchase vacant and blighted tax-delinquent properties from the government, as well as properties with affordability restrictions and market-rate properties. Private property can also be donated to a land trust.

The two sites acquired by Mi Casa were awarded to the land trust conditionally in April, after the DHCD first put out a solicitation for offers in November to build affordable single-family homes on vacant and blighted properties in historic Anacostia. Mi Casa's acquisition of the two lots was officially completed this month after a public hearing was held, and it will build a ­single-family home on each lot, to be sold to buyers earning not more than 50 percent of the area median income. Construction is expected to be completed around August or September 2018.

“We love the idea of community control and long-term affordability,” Elin Zurbrigg, deputy director of Mi Casa, said as she explained the concept of a land trust at a recent meeting of Anacostia community members.

The governance structure of a land trust ensures that the interests of residents are well-represented, she said, because one-third of its board of directors is made up of land trust homeowners and renters, and another third consists of residents of the surrounding communities who do not lease land from the trust. And a trust achieves permanent affordability by separating the land from the house built on it: the trust retains ownership of the land, while the buyer purchases only the house at a lower price, and agrees to a resale price that puts a cap on the profit that the buyer can make. For those who cannot afford homeownership, land trusts can also provide a supply of affordable rental housing.

The aim is to slowly acquire more parcels of land in Anacostia to grow the trust, said Kratz. The trust has an acquisition portfolio of $550,000, raised through commitments from Citi and JP Morgan Chase.

Kratz is well aware that looming over the bridge park project is what he calls “the G-word”: gentrification. He wants to tackle that head-on and to stave off the risk of displacing residents even as he works to bring economic development and a world-class public space to the city.

Crucial to that, he said, is being intentional in “ensuring we’re answering the question of who this is for” — residents.