Folsom Lake was drained to less than 15% of its capacity during the California drought in 2015. This record low water level exposed many hidden historical gold rush sites from the 1850s. On numerous hikes across the drought parched Folsom Lake bed, Kevin Knauss took numerous photos of historical sites and structures that were usually covered by water. Knauss researched the various sites and structures, some dating back to the 1850s, and marked the spots on various maps included in the book. He also includes newspaper accounts and recollections of the life and landscape as it was witnessed before Folsom Dam was built at the confluence of the North and South forks of the American River.Hidden History Beneath Folsom Lake, Folsom Dam to Rock Springs, is part of a five book series. The first book, Folsom Lake to Rock Springs visits the historical sites on the western side of the North Fork of the American River. Sites and structures chronicled include the North Fork Ditch, Rose Springs, Rose Springs dump site, an old gold mine, and Native American grinding holes.