Colorado River Compact

Apportions the waters of the Colorado River Basin. Congress authorized seven states in 1921 to negotiate the compact. Six of them ratified the compact promptly, but Arizona did not join until 1944. An amendment was adopted in 1925 to waive the requirement that all seven states approve. Congress accepted the revision in the 1928 Boulder Canyon Project Act, which however, required California’s approval. California approved the amended compact in 1929.