USA - Lake Powell was 23.4% full on July 19. It was last full in 1983. If its level falls more, that could create environmental catastrophe by stopping the river flowing through the Grand Canyon, a situation known as “dead pool.” The crisis could create ripple effects nationwide. Nearly half of the country’s vegetables and more than three-quarters of its fruits and nuts are grown in California, according to the state’s Food and Agriculture Department. A substantial amount of California crops are irrigated with Colorado River water. Meanwhile, California and the six other states that collaboratively manage the river have been unable to reach a compromise on what to do about the problem.