In 1978, the Board of Natural Resources and Conservation granted water reservations to 14 conservation districts (CDs) in the Yellowstone River basin. Ten CDs were granted reservations in the upper Missouri River basin in 1992, and eleven CDs were given reservations in the lower and Little Missouri River basins in 1994. Some CDs have reservations in more than one basin. The Conservation Districts Bureau provides legal, technical, and programmatic assistance to conservation districts in administering water reservations.
At the end of the 2014 irrigation season, there were a total of 220 CD water reservation projects in the Yellowstone River basin. These projects put to use 99,438 acre-feet of water.
Conservation Districts have issued 82 reserved water use authorizations in the Missouri River basin, developing 29,246 acre-feet of water.