The Walnut Grove Dam was built north of Wickenburg, Arizona, United States, along the Hassayampa River.

In the words of one prospector, the river was a place "where at times an ocean steamer might be floated, and where at other seasons ... the fish must carry canteens.

"[2]: 284 Into this environment came two brothers, Wells & DeWitt Bates, who filed 63 placer gold mining claims in 1881 along the Hassayampa.

Wells Bates spent a portion of 1883 in the area, making legal arrangements related to building a dam, including claiming all the water in the Hassayampa.

[2]: 286  The brothers established the Walnut Grove Water Storage Company for the purpose of creating a dam.

[2]: 293 A site some 20 mi (32 km) north of Wickenburg was chosen for the dam, mostly for gold mining, but also for general purpose irrigation.

But Robinson soon discovered that the Bates brothers were more interested in selling stock than building an actually sturdy dam.

[5] Robinson's equally competent assistant, John M. Currier, resigned shortly thereafter, noting that the firm of Nagle and Leonard was doing very shoddy work.

Dillingham Bates was also replaced as president of the Walnut Grove Water Storage Company by the wealthy Henry Spingler Van Beuren.

Van Beuren appointed a new Chief Engineer: Alexander Oswald Brodie, who would go on to become Territorial Governor of Arizona.

Projects to improve the dam, and to prepare downstream areas for mining, continued until its collapse, and were overseen by Brodie as a nominal engineer.

Wells Bates ordered an expansion of the spillway, enlisting Benjamin S. Church, dean of the American Hydraulic Engineers.

[2]: 296  Van Beuren and some of his family visited the dam in the winter of 1889/1890, enjoying the reservoir and the boating it offered.

Van Beuren oversaw the delivery of the hydraulic equipment to begin gold mining, and was away in Phoenix for that purpose when the dam burst.

Burke knew the territory, and at 2:30 in the afternoon Brown gave him the camp's best horse and told him to rush to warn those downriver that the dam would soon fail.

[4][6] A second messenger, William Akard (who had earlier found Burke drunk at a ranch), was caught and killed in the deluge just before he could reach the camp at the diversion dam to warn them.

[8] News of the disaster reached Prescott (the county seat) at 8 that evening, and Sheriff Buckey O'Neill assembled a rescue party.

[3][9] The week after, John Wesley Powell gave a brusque and damning account of the collapse to Congress, noting "an ignorant engineer believes the dam is safe ... for he has never seen it at flood time."

[2]: 302  The haphazard construction process led to considerable finger pointing, and no individual or company was ever held liable.

It owed $100,000 to the Farmers' Loan and Trust Company in a mortgage of the placer claims, which was foreclosed on in October 1891.

[2]: 303 Historian David B. Dill, Jr. notes "from its conception, the Walnut Grove dam had been a disaster in the making."

He faults Blake for lacking experience, the company for not following Robinson's plans, Nagle & Leonard for shoddy construction, and management for failing to warn those downriver.

He notes that the disaster was little considered in Arizona, emblematic of a lack of corporate conscience and a popular admiration of the wealthy.