With heavy rainfall predicted to pound the Tucson area the next few days, city and county officials said the region’s infrastructure can likely handle what nature throws at it.
Suzanne Shields, Pima County Regional Flood Control District director, said local bridges have held up against past flooding and there’s no reason to think otherwise now.
She said most of the problems with heavy storm runoff arise when water levels spill over wash embankments and into nearby roads.
To keep an eye on water levels, the county operates a flood-warning system that includes 96 gauges spread across the region to track rainfall and water-flow levels in Southern Arizona.
“We’ve operated this system since the 1980s, and we have a good idea of what the travel time has been from other storm events from one point to another,” Shields said.
For instance, Shields said it takes about an hour for water from the Tanque Verde Wash at Sabino Canyon Road to reach the Rillito Wash at Dodge Boulevard.
When water levels reach dangerous levels, the county flood district contacts transportation departments across the region so they can close the affected roads and bridges before significant flooding occurs.
She said last week’s record rain produced about 10-foot-high water levels along the Santa Cruz River, which she classified as a 10-year event.
Shields said it takes more than 12 feet of water before it begins pushing against bridges and spilling over.
The county expects a total rainfall from Tuesday through Thursday to range between 3 and 5 inches, with the 5 inches estimated for higher elevations.
Last week, city officials feared torrents of water might flow north along the Santa Cruz River and wreak havoc on city bridges. The flooding never happened.
But even if Hurricane Odile soaks the area south of Pima County, Shields said county stream gauges at Tubac, Elephant Head Road, and Continental Road Bridge in Green Valley will detect rising water levels well before they reach Tucson and give officials time to react.
“We will have advance warning if there is major flow,” Shields said.
City officials were somewhat less forthcoming.
Five minutes before a scheduled interview with city Transportation Director Daryl Cole on Tuesday afternoon to discuss bridge conditions following the last storm, the City Manager’s Office abruptly canceled the meeting.
The Star had requested information about post-storm bridge inspections last week, after city officials initially indicated plans to close all the bridges over the Santa Cruz River in advance of anticipated flooding only to change their minds minutes later.
A spokesperson for the City Manager’s Office said Cole and city transportation employees were too busy preparing for the new storm to discuss city bridges.
Cole said the city’s bridges are fine, and echoed Shields’ position the problem isn’t the integrity of bridges, but water overrunning wash embankments and bridges.
