Walnut Grove Dam Accident
Coordinates: 34 ° 11 ′ 36.6 ″ N , 112 ° 32 ′ 30 ″ W.
_location_map.svg){kind=small}
The Walnut Grove Dam on the Hassayampa River in Arizona , United States, broke at 2:00 a.m. on February 22, 1890 . By the tidal wave between 50 and 150 people died.
The dam was two years old (construction time around 1886–1887) and consisted of a rock fill with a cladding of wooden beams on the water side . The height of the dam was 110 feet (33.5 m) and the storage capacity was 50,000 acre-feet (62 million cubic meters). The dam stood 40 miles (64 km) above Wickenburg . The reservoir was 900 acres (364 hectares = 3.64 km²).
The dam was built in the 1880s by a water utility (Walnut Grove Water Storage Co.) along with a second dam. The upper of the two dams, the Walnut Grove Dam, had a flood discharge measuring 6 * 26 feet (1.8 * 7.8 m), which had been blasted out of the rock at one of the two abutments. On February 18, there was heavy rainfall in the Bradshaw Mountains. They lasted three days. On the third day the water behind the dam rose 18 inches (45.7 cm) per hour. The runoff from the 500 square mile catchment area was so strong that the flood relief, which was too small, was insufficient. The steward commissioned 15 men to enlarge it. The dam was nevertheless overflowed up to 3 feet (0.9 m) high for six hours. Only after this long time did it break and a tidal wave fell down Jesus Canyon. Work on the second dam was carried out 15 miles below. An attempt was made to warn these people (and those below) and a rider was sent out. However, the distance and bad weather prevented him from reaching his destination. According to another version of the story, he stopped at a bar to have a drink. It wasn't just a drink, and so he forgot the message he was supposed to deliver.
The destruction caused by the tidal wave was great. According to eyewitness accounts, it was up to 100 feet (30 m) tall. It dragged large boulders and trees and destroyed two cities. The number of flood victims fluctuates in the various reports between 50, 70, 80, 70–85, 70–100 or 150 deaths. The property damage was also great. Among other things, the farm of Henry Wickenburg, who gave the city its name, was destroyed. Allegedly, two safes were buried with gold coins valued at $ 9,000, which treasure hunters would later look for in vain.
