City creek to reach its peak next week
May 18, 2023, 7:07 PM | Updated: 8:59 pm
SALT LAKE CITY — There’s still a lot of snow in Utah’s highest mountains that needs to melt. So far, apart from localized flooding, the runoff has not caused widespread damage.
City Creek is the next creek of concern for Salt Lake City, the same creek which infamously ran down State Street in 1983.
“We find that City Creek is rising, and we anticipate it to get up to near bank-full Tuesday or Wednesday next week,” said Brian McInerney, a hydrologist for Salt Lake City Public Utilities.
That drainage still has 230% of normal snowpack. Right now, it’s melting at a rate of an inch a day due to the recent warm-up.
“Which is a pretty hefty rate in that channel,” the hydrologist said. “It’s designed to hold something right around there. But if we bump this up to 2 inches a day or 2 1/2 inches per day, that channel is too small to handle that volume of water coming down, and that’s what we’re worried about.“
McInerney anticipates the creek will be running 130 ft.³ per second on Tuesday, which is good. But, he said, 200 CFS is a level of concern. A basketball is about a cubic foot. So, 200 ft.³ per second would be about the same as 200 basketballs flowing by in one second.”
Parleys Creek is being controlled by releases from Little Dell and Mountain Dell reservoirs. Salt Lake City Public Utilities is trying to release an amount that’s just right.
“They’re trying to fill Little Dell, yet not allow it to flood downstream. So, it’s kind of a tight rope. Right now they’re doing a good job,” McInerney said.
Emigration and Red Butte Creeks don’t have enough snow left to produce floodwaters, even if they have high flows. But Big and Little Cottonwood Canyons still have snowpack three times normal, and much of it hasn’t started to melt.
“We are warming at a pretty good clip here, and that should start bringing a lot of that snow off,” the hydrologist said. “So the peak should most likely be in late June sometime.“
Possibly into July.
“We’re going to see high flows really from now until July. But the peaks will most likely come the third week of June sometime,” McInerney said.
This runoff period is a marathon, and with record-breaking snowpack, it will last longer than usual.
