Cache may be the wettest county in Utah now, but it was even more so in the past. The valley was submerged under Lake Bonneville until about 15,000 years ago. After the lake drained out, the Shoshone managed the land for thousands of years. They shared the rivers with beaver, whose dams helped weather drought, flood, and fire. Trapping in the early 1800s and canals for irrigation starting in the late 1850s dried up the land considerably.