The only flowing stream associated with Scotts Bluff National Monument is the North Platte River. The river is also the Monument’s north boundary for approximately one and one-fourth miles. Because it is a non-navigable river, the Monument’s boundary extends to the center of the channel. Also the river’s floodplain adjoins a portion of the Monument's north boundary. Historically, the North Platte River flooded in the spring, but today several dams upstream within the river basin control much of the river’s flow, thus making flood events rare. These dams were constructed for flood control, the generation of electricity and the diversion of water for irrigation. The pioneers knew the river as much wider and more dangerous than it is today.
Three irrigation canals operated by the Central Irrigation District, the Gering Irrigation District, and the Gering/Fort Laramie Irrigation District, traverse the Monument. They deliver irrigation water to farm fields in the North Platte River Valley. The irrigation season is normally from May 1 to October 15. At other times of the year, the irrigation canals are dry. These canals predate the establishment of the Monument and the federal government recognizes an easement or right-of-way for each one. In several places these irrigation canals have produced riparian habitat.