The high Rocky Mountains create a barrier between eastern and western Colorado.
Weather patterns come from the west due to the rotation of the earth.
Moisture from the Pacific Ocean travels east to Colorado. The western slope receives more annual precipitation than the eastern slope. Although a tour through Colorado's countrysides would suggest the opposite, because the eastern slope out to about 60 miles into the prairies from the foothill seems so green and lush. Colorado has a long history of water rights, water usage and ownership of waters conflicts. Its legal case law has some of the most important precedents in U.S. Water Rights law.