A model showing the new subterranean features where the Enid Haupt garden now resides, as Smithsonian officials and architects announce major changes to several core buildings in November. (Bill O'Leary/The Washington Post)

The Smithsonian Institution proposes to destroy one of Washington’s most beloved outdoor spaces: the Enid A. Haupt Garden. Situated behind the iconic Smithsonian Castle and nestled between the Arts and Industries Building and the Freer Gallery of Art, the garden is, arguably, one of the few peaceful and contemplative places on the Mall.

Conceived by then-Smithsonian Secretary S. Dillon Ripley, this quadrangle complex comprises not only the garden but also the pavilion entrances to the underground Arthur M. Sackler Gallery, the National Museum of African Art and the S. Dillon Ripley Center. Fronting Independence Avenue SW are also the garden’s splendid entrance gates, based on a design by Castle architect James Renwick Jr. himself.

I have a personal interest in saving the Renwick Gates because I was responsible for the concept and the oversight of their design and erection. The quadrangle complex was hailed by the American Institute of Architects as a masterful blending of the old and new when it opened in 1987. Its proposed demolition is being challenged by the National Trust for Historic Preservation, the Committee of 100 on the Federal City and the D.C. Preservation League.

A year and a half ago, then-Smithsonian Secretary G. Wayne Clough unveiled the Smithsonian South Mall Campus Master Plan, an element of which calls for the removal of historic features of the quadrangle complex. This is no small master plan. It also proposes extensive improvements throughout six museums (from the Freer to the Hirshhorn), including renovated and expanded gallery space, better visitor access and amenities, and much-needed office space.

The plan is a joint vision of Smithsonian management and the Danish architectural firm BIG-Bjarke Ingels Group, famous for bold, futuristic and bravura-packed designs. The selection of this firm for a project demanding subtlety, nuance and sensitivity to a historic setting is questionable.

This multi-decade and increasingly expensive master plan (now estimated to cost $2 billion ) proposes some admirable objectives; chief among them is much-needed restoration of the Castle itself. However, the quadrangle’s garden, gates and pavilions have become historically significant and a tangible thread of the Smithsonian’s 175-year physical development in our nation’s capital, no less worthy of preservation for future generations than the Castle itself.

Bjarke Ingels’s replacement is a wasteland of skylights reminiscent of a regional shopping mall. The erupting “swoops” of turf, glass and steel lack respect for the surrounding historic buildings. Peaceful and contemplative are replaced with arid, windswept and unfriendly.

The Smithsonian should have more respect for its Castle and the institution’s own history.

The writer is a former curator for the Smithsonian Institution.