Officials urge caution as runoff-swollen rivers rise
June 3, 2011
GRAND COUNTY – Warmer temperatures in the high country since the start of the month are intensifying runoff in mountain valleys.
Forecasters are saying the Colorado River could peak by Wednesday of next week, then after a slight dip in flows, peak higher still in mid-June.
The Upper Colorado River may rise another 1.5 to 2 feet by next week, with flows in the 8,700 cubic feet per second (cfs) range at the Kremmling gauge.
The river basin snowpack is sitting at a whopping 277 percent of average for early June, with a much later start of the runoff than in average years.
Rather than experiencing a series of sustained high temperatures that can cause serious flooding, like last year, the hope among river watchers is for a pattern of warm temperatures followed by cooler temperatures to slow down runoff.
“We’re at the mercy of the temperatures.” said Don Meyer, senior water resources engineer of the Colorado River District. “We’re hoping for temperatures fluctuating between the higher- and the lower-than-average.”
Along the main stem of the Colorado River in higher elevations, residents can expect most tributaries to leave their banks.
Most vulnerable to Colorado flooding are the downstream cities of Palisade, Grand Junction and Fruita, Meyer said.
And, the area’s reservoirs are expected to spill.
“Everybody’s spilling,” he said.
Brian Werner of the Northern Colorado Water Conservancy District, which manages the Colorado-Big Thompson Project in Grand County, agrees. Not only is there an abundance of snowpack, analyses show the snow to be heavy with water.
“There’s way more water in those hills than we have buckets to put it in,” he said. “We will never see another runoff like this in our lifetimes.”
Water is running near or at bank levels along most rivers and streams, with some flooding in low-lying areas from Parshall to Kremmling. Already, a few culverts have been replaced, according to Trevor Denney of the Grand County Office of Emergency Management.
Muddy and Troublesome creeks are flooding, and Wolford Mountain Reservoir has been spilling.
Williams Fork Reservoir may spill next week, which would increase Colorado River flows, Meyer said.
Meanwhile, inflows into Colorado-Big Thompson reservoirs increased over the weekend, and releases out of most reservoirs are at maximum safe levels right now.
As of Thursday, Lake Granby was about 27 feet from the top of its spillway, releasing at maximum flow from the outlets below. Northern is expected to conduct a controlled spill by opening the dam’s top gates when the lake rises another 6.5 feet, according to Werner. And releases from Willow Creek dam had been increased to a robust 1,200 cfs over the weekend due to accelerated snowmelt.
Water levels at Willow Creek were rising by a foot per day, according to Kara Lamb of the Bureau of Reclamation, and property owners along the creek are reporting widespread flooding.
The Fraser River as of Wednesday was “just getting going,” Denney said. “We haven’t started melting yet on the east end up high.”
The Grand County Office of Emergency Management is warning citizens to be cautious around the area’s fast-flowing rivers, especially to keep pets and children away.
And although there are free sandbags available for properties threatened by high water, they are meant to “protect homes, not flowerbeds,” Denney said.
– Tonya Bina can be reached at 970-887-3334 ext.19603