City of Riverton saved from flooding by 40′ of riverbank; Water level not seen since 1921; 8,500 acres without water
(Riverton, Wyo.) – Forty feet. That’s how close the Big Wind River came to breaching an irrigation canal that would’ve resulted in a catastrophic flood that would’ve inundated the City of Riverton. The river breached the Riverton Valley Irrigation District Canal on Saturday six miles west of the city by cutting a new channel below the district’s headgate.
“We tried to contain the breaches, but there was just too much water coming down the river,” said RVID Ditch Rider Wayne Neal. Ultimately, Neal said a massive breach downstream from the headgate washed out the canal. The breach allowed the flooding from a new channel of the river to return to the main channel.
Just downstream from the major breach,\ the record river flow kept eating away at the bank, but stalled 40 feet from the canal.
“We came within 40 feet of a flood of Biblical proportions,” said Neal, who gathered with Loren Smith and Joshua Fredrickson from the Wyoming State Engineers office and RVID’s Kent Haun just above the washed out canal Monday morning.
“We saved the city of Riverton, but now there are 8,500 irrigated acres along the canal without water,” said Haun. “We’re planning a Wednesday meeting with all of our irrigators to explain what happened and what we’re trying to do.” The meeting is tentatively planned for 10 a.m. at the Riverton Branch Library.
A total of at least three different river breaches upstream from the headgate were noted this morning in video from a drone flyover. Water from those breaches created the new channel, which then flowed behind the headgate and over the canal on its way back to the river.
Neal said when the canal reached its maximum level, the headgate was turned off. The new channel of flood water spilled over the canal bank with the river flow continuing down the canal to a series of old flood gates and sand traps, that were absorbing the extra water. Debris began covering the sand traps. That’s where the river bank erosion came close to breaching the canal again, with nothing down canal to stop it.
“Mother Nature did this,” Neal said. “We did what we could do, but we were basically helpless.”
The State Engineer’s Smith said the river flow set a new all time record. “Plain and simple that was a 100-year flood. The last time the river was this high was in 1921, and this year we exceeded that record.”
The river reached 12.2 feet at Riverton, a record level on Friday afternoon.