Floodwaters Overtop Dam in Prescott as City Declares Emergency

The National Weather Service had warned of flash flooding in Yavapai County before the storms arrived, but the volume of water that hit Prescott on Sunday exceeded the capacity of local infrastructure. Mayor Cathey Rusing declared a state of emergency after continuous rainfall caused widespread flooding and forced Watson Lake Dam, also known as Granite Dam, to overtop.

City officials activated the Emergency Operations Center at 8 a.m. on Monday to coordinate the response across all departments. The city is working alongside Yavapai County and the state of Arizona to manage the situation. Before the storms, the Public Works Department opened the 36-inch release valve at Watson Lake and the crosscut channel to Willow Lake to lower the reservoir and create space for incoming water.

The dam is rated to handle water flowing up to 10 feet over the top. Water flowing into the reservoir peaked at more than 4,000 cubic feet per second. Saturated ground in the mountains produced two to three times the normal runoff, according to city officials. Flows have since dropped to about 1,680 cubic feet per second. Officials are continuously monitoring the dam for structural concerns. Upper Goldwater Reservoir has also topped, while Lower Goldwater Reservoir is under close watch. Willow Lake Dam stands 7.5 feet below its spillway with no reported structural issues.

The National Weather Service issued a Flood Watch for Yavapai County on Thursday, Oct. 29. The watch was in effect from Saturday evening through late Sunday night. It warned of flash flooding from heavy rain falling on already saturated ground.

All low water crossings in the city are currently closed. Specific road closures include Sixth Street, Sonora Drive at Campbell Street, South Granite Street between West Aubrey Street and West Leroux Street, Walden Road off White Spar Road, and Brannen Avenue at Miller Valley Road. Several traffic signals went out during the day, and drivers are instructed to treat non-functional signals as four-way stops. Granite Creek Park is also closed to the public.

Residents can obtain sand and sandbags at the White Spar Fire Station, the Airport Fire Station, and CAFMA Fire Station 51. People must bring their own shovels and fill the bags themselves. Yavapai County and the American Red Cross have opened a shelter for displaced residents in the Yavapai College Prescott Campus Gymnasium at 1100 E. Sheldon.