During the Great Flood of 1862 the American River flooded massively , putting much of Sacramento under water for three months . Newly elected Governor Leland Stanford had to travel to his inauguration by rowboat ; shortly after , the state government moved temporarily to San Francisco . A significant contributor to the flood damage was the debris washed down by hydraulic mining , which had choked the river channel and reduced its capacity to drain floodwaters . In response , the city of Sacramento undertook a massive project to raise its streets and buildings as much as . Many of original sidewalks and the first floors of buildings remain as subterranean spaces underneath today 's streets
Great Flood of 1862
Great Flood of 1862
American River