Destiny Hansberry, 4, checks out the fresh fish while shopping with her family at the Maine Avenue Fish Market on the Southwest waterfront. (Amanda Voisard/The Washington Post)

Southwest, by far the smallest of the District’s four quadrants, is being considered for big changes by the National Capital Planning Commission.

Other than the Mandarin Oriental Hotel and the Arena Stage, complete with a $135 million makeover by Vancouver architect Bing Thom, Southwest offers little to attract visitors south of the National Mall, despite having a waterfront along the Washington Channel and four Metro stations.

This is in part thanks to a block-like office canyon that makes a walk south of the Mall unappealing; overpasses for Interstate-395 and railroad tracks don’t help, either.

Last week the commission, which governs planning for the federal government, issued a 94-page draft plan to transform 110 acres between 6th and 12th streets into an “ecodistrict” over the next 20-25 years.

Some of the proposals are dramatic — and expensive: building a deck over the 12th Street ramp, building on under-used federal property and overhauling the Energy Department’s ominous-looking behemoth headquarters. But they would create another 1 million square feet of office space, 1.8 million square feet of housing and 1.2 million square feet of cultural attractions, including five sites for new memorials and a proposed National Women’s History Museum.

By upgrading its facilities with energy-efficient technology, the commission estimates that the federal government could also reduce greenhouse gas emissions in the area by 51 percent and water use by 70 percent.

“We have the opportunity to transform a disconnected area and once again make it a vital part of the city as the plan’s recommendations are implemented over time,” commission Chairman L. Preston Bryant Jr. said.

Private developers are already making major investments in Southwest. Developers PN Hoffman and Madison Marquette are planning an overhaul of the Southwest Waterfront beginning next year and are seeking $750 million in capital investments. JBG Cos. has announced new development and has begun retail upgrades at L’Enfant Plaza.