Carnegie library was built downtown in 1908; it burned down after the library moved in 1966. Nampa Public Library was then located on the corner of 1st Street and 11th Avenue South in the old bank building. A new library, located on 12th Avenue South, was opened in March 2015. Deer Flat Reservoir, an offstream irrigation storage reservoir, was constructed by the United States Bureau of Reclamation between 1906 and 1911. Known locally as Lake Lowell, it is surrounded by the Deer Flat National Wildlife Refuge, which was established in 1909 by President Theodore Roosevelt. The refuge is administered by the U.S. Fish and Wildlife Service. Lake Lowell is filled by the concrete New York Canal; the water is diverted from the Boise River a few miles below Lucky Peak Dam. The Idaho State School and Hospital was built northwest of Nampa in 1910, for the state's developmentally challenged population, and opened in 1918. The institution was largely self-sufficient, with a large farm staffed by the residents. The higher-functioning residents also cared for residents who could not care for themselves. Much has changed in the care of persons with developmental disabilities from the time of the state school's opening. The land for the old farm was sold and are now golf courses (Centennial and Ridgecrest), and the residents no longer give primary care to other residents. The institution is modernized and remains in operation, though a few of the oldest buildings are now used to house juvenile offenders. Nampa held an annual harvest festival and farmers' market from about 1908, a time of celebration and community fun. From this festival emerged the Snake River Stampede Rodeo in 1937, which continues to this day. It is one of the top 12 rodeos in the pro rodeo circuits. A local congregation of the Church of the Nazarene built a small elementary school in 1913, later growing to Northwest Nazarene College in 1915 and finally to Northwest Nazarene University. The university currently has a student body of 2,500 undergraduate and graduate students. Karcher Mall opened in 1965, the first enclosed shopping mall in the Treasure Valley. Many area residents have memories of having an Orange Julius, sitting on Santa's lap, or playing games at the Red Baron arcade in the mall. Karcher Mall was "the place to gather" for several decades until the Boise Towne Square mall was built in Boise in 1988,