A Washington D.C.-based education and advocacy nonprofit is suing the U.S. Department of the Interior over its renovation of the Lincoln Memorial Reflecting Pool .

The Cultural Landscape Foundation (TCLF), which was founded in 1998 to better connect Americans to the nation’s landscape heritage, backed a lawsuit on April 12 in the U.S. District Court in Washington claiming that painting the basin of the Reflecting Pool “American flag blue” violates federal law.

In early April, the Department of the Interior awarded a no-bid contract to the Virginia firm Atlantic Industrial Coatings to waterproof and paint the pool.…