Teatown Lake Reservation — an Ossining-based nonprofit environmental education center and nature preserve, whose mission is to inspire its community to lifelong environmental stewardship — will break ground on a 22,000-square-foot, $26 million development on Oct. 9. With Manhattan-based Starr Whitehouse as the landscape architect, the development will create an accessible, ecologically enhanced pedestrian campus with reconfigured access and operations. As the focal point of the redevelopment, Teatown will debut a 5,400-square-foot Education Center, designed by Brooklyn’s nARCHITECTS, that will feature teaching and education spaces in its interior and on its exterior deck and green roof. “For more than 60 years, Teatown has been one of the Hudson Valley’s most cherished community resources and environmental education centers, providing the region with our team’s expert knowledge in land protection and conservation,” Teatown Executive Director Kevin Carter said in a statement. The campus will also be anchored by a renovated historic Nature Center, housed in a 15,000-square-foot, 1920s Tudor-style building that served the original estate, once owned by General Electric Chairman Gerard Swope Sr., as stables.