Residents should exercise caution in coming days as washes around Maricopa are likely to start flowing due to heavy rain combined with runoff from thunderstorms near Tucson.
The National Weather Service is predicting a 20-40 percent chance of thunderstorms for the Tucson area starting Wednesday night and continuing into next week.
Historically, such deluges to the south top off Maricopa’s washes within three days, or sooner, Maricopa Flood Control District Manager David Alley said.
“The intensity of that [flooding] depends, of course, on how much rain falls there, and whether it rains in Maricopa as well,” Alley said.
Maricopa has a 20-30 percent chance of rain during the same period.
The Maricopa Public Works department manages gates in Rancho El Dorado and on Porter Road, south of Maricopa-Casa Grande Highway, which are typically closed when flooded.
However, should drivers be confronted with a flooded roadway, NWS and local public-safety officials advise, “turn around, don’t drown.”
“Don’t take the chance; just be patient,” Alley said.
Water can move with so much force even the biggest and heaviest pickup trucks can be swept away, he said.
Also, he warned, the roadways could have unseen erosion under the water’s surface and attempts to cross may result in vehicles becoming stuck and passengers needing to be rescued.
Any would-be swimmers should also beware, Alley said.
Not only could they be swept away by the powerful current, but the water also often carries harmful bacteria and chemicals.
“Upstream there are feedlots and farms, so that water is coming from agricultural land and it can be carrying all kinds of [harmful] stuff,” he said.
Over the past year, MFCD has been working to clear washes of debris and the invasive salt cedar which slow dissipation of water and promote flooding.
Alley said the Santa Rosa Wash is in “really good shape” and can handle quite a lot of water. However, the Santa Cruz Wash has seen fewer improvements and is less suited to handle larger flows, meaning it could fill up faster and take longer to dry.
Though this increases the chance of flooding, residents should not be worried as most of the troublesome areas with the Santa Cruz are south of Maricopa in undeveloped land, he said.
MFCD intends to make similar improvements to the Santa Cruz Wash, and a request for proposal for the project has been issued. When the district receives a qualified bid, improvements can begin immediately, Alley said; weather permitting, of course.