…peak runoff is coming as much as two to three weeks earlier than it did as recently as the 1970s — an astounding change in a short time, measured on the scale of Earth history.
The researchers also pinned the timing of snowmelt and runoff to changes in global and regional temperatures, as well as reduced snowfall during the study period. The published their findings in the Journal of Climate last week.
Water managers have already been scrambling to understand how the changes will affect operation of reservoirs and diversions for agricultural and municipal use, but the shift in timing could also have huge impacts on aquatic ecosystems in the southern Rockies and desert Southwest. At issue is the growing gap between spring runoff flows and monsoon rains later in the summer. Fish native to the mountain streams of the region already live in a narrow window of flows and temperatures. If spring streamflows drop earlier in the year, trout and other fish could be exposed to longer dry periods…
“I expect that it will even further limit the amount of habitat,” she said. Hedwall and her colleagues have had to undertake intensive management efforts to maintain populations of some aquatic species.
The changes could also result in fish spawning earlier. Biologists think that fish may be able to adapt to those changes, but the real issue is year-round habitat. With longer, drier summers, it’s likely that many young fish won’t have enough habitat to survive. Water stored in reservoirs could provide a buffer against shrinking aquatic habitat if it’s used for environmental purposes.
“Even though things are flowing impressively right now, the overall volume this summer season is still going to be below average,” said Mike Gillespie, snow survey supervisor with the National Resources Conservation Service. The Colorado Basin’s snowpack is 57 percent of average, but reservoir storage levels are averaging 114 percent of normal — which means water supply shortages aren’t expected in the foreseeable future. Snowfall through much of winter was well below normal, but the springtime brought along a few storms that lessened the impact. “It’s not going to be a great year for anyone, but it’s still not a disaster for anyone, either,” Gillespie said.
The Blue River below Dillon Reservoir and the Colorado River near Kremmling are both flowing at more than double the average over the previous 47 years, according to the U.S. Geological Survey at http://waterdata.usgs.gov But while the white stuff is melting early this spring, last year’s larger snowpack flowed out even more quickly; the remaining snowpack by June 1 this year was 185 percent of 2009. The Blue River below Dillon Reservoir is gushing at about 1,410 cubic feet per second. “Last year we saw it as high as 1,850,” Silverthorne public works director Bill Linfield said. “Usually our peak flows in the Lower Blue come in late June, even up to the Fourth of July.”
From the Cañon City Daily Record (Charlotte Burroughs):
[Arkansas River Outfitters owner Tony Keenan] noted the Arkansas River had hit its peak last week at 4,200 cubic feet per second, but recently dropped to 2,500 cfs. “June is the best time for the water level while July and August is the best time for weather,” Keenan said. At the same time, the voluntary management flow program keeps the level at 700 cfs at Wellsville for rafters during July and part of August. Compared to two years ago, “the water is pretty much at typical levels right now once you get the snow melt across the Arkansas River valley,” said National Weather Service metrologist Mike Nosko. “The flood stage is at 9 foot,” Nosko said. “We’re plenty below the flood stage.”
The Arkansas River was expected to hit flood stage at midnight and high, fast flows are expected through Tuesday as rapid snowmelt continues across the high country due to record warm temperatures. The National Weather Service in Pueblo issued a flood warning Saturday, predicting the river would crest at 9.2 feet around midnight and remain high through Tuesday before falling below the flood stage of 9 feet in Canon City. The flooding was expected to be minor, as the river has to rise to 11 feet to be considered flowing at a moderate flooding stage…
The river was flowing at 4,060 cubic feet per second at 2 p.m. Saturday at Parkdale, 10 miles west of Canon City, where it had already crested at 4,200 cfs last Sunday. The 4,060 cubic feet per second at Parkdale equates to about an 8.71 foot level in Canon City.
Rob White, Arkansas Headwaters Recreation Area park manager, said the river peaked Sunday – Browns Canyon was running at 3,160 cubic feet per second and the Salida gauge recorded 3,130 cfs. A high water advisory for boaters was in effect for the Numbers and Royal Gorge Tuesday. Wednesday, Browns Canyon was running 2,430 cfs, Royal Gorge was at 3,150 cfs and the Numbers was at 1,900 Wednesday. River levels are coming down.
The [North Poudre Irrigation Company] appropriated one acre-foot of early water per share this year, the first time in several years, because of the good supply of water. The total NPIC appropriation this year is six acre-feet, including 2.9 acre-feet of multiple use water, 2.18 acre-feet of ag water and the early water appropriation.
As the area continues to recover from the long drought, soil moisture is finally being replenished. “It’s a lot better than we’ve had for a number of years,” Smith said. Some crops are benefitting from the spring moisture, notably hay and pasture grass. Howard Diehl, whose family has some acreage in dryland crops, said the cool, wet weather has been great for grass. Winter wheat has also benefited, he said…
Stream runoff this spring is predicted to be below normal, according to Brian Werner of Northern Water. Runoff on the Poudre River is projected to be 85 percent of average, with the Big Thompson at 80 percent. The Western Slope, which provides most of the Colorado-Big Thompson storage, is predicted to produce runoff that’s only 75 to 80 percent of average. On the plus side, Werner noted, reservoir storage is very good at present. Local storage is 35 percent above average, and C-BT reservoirs are 15 percent above average. Spring moisture is keeping pressure off the reservoirs, boding well for available water later in the season.
[Boulder Creek] was flowing Friday at a rate of 120 cubic feet per second. After water begins spilling from Barker Reservoir, creek flows could increase to 320 to 420 cubic feet per second, according to city officials. Flooding is not expected to occur unless a thunderstorm takes place in or around Boulder Canyon, but the increased flow could make swimming and wading dangerous, the city said. Parents are encouraged to keep their children from swimming, wading or playing near the water’s edge.
The Vail Whitewater Park put the world’s top kayakers to the test as gushing snowmelt from the nearby Gore Mountain Range turned the river a muddy orange and carried trees, root balls and other debris into the competition wave. A low bridge ripped the paddle from one competitor’s hand during practice and others suffered scratches to the face and hands from wood collecting in the eddies. “The conditions were incredibly challenging,” head judge Clay Wright said of the contest. “I’ve never seen Gore Creek this high. I thought we were going to see a mobile home floating through any minute.”
Between dodging debris, Dustin Urban of Buena Vista landed a dizzying array of aerial “loops” and whirling “McNasty’s” to top the men’s competition with 590 points. Second place went to 16-year-old junior freestyle world champion Jason Craig of Reno, 90 points behind, followed by Casper Van Kalmouth of the Netherlands. “It was probably the craziest finals I’ve ever participated in,” Urban said. “Changing water levels are always a factor in kayaking, but not quite to the extreme they were today. The wave was always changing. We were all figuring it out as we went.”
Perennial women’s champion and reigning women’s freestyle world champion Emily Jackson of Tennessee went from last to first in her final ride of the three-women women’s finals, notching 260 points to top Australian Tanya Faux’s 180 points. Paddling for Buena Vista’s Colorado Kayak Supply, Haley Mills finished third with 140…
SUP sprint: Hawaiian 15-year-old Noa Ginella was the top paddle surfer among the races’ 40 starters, riding the rising river down the technical 3.5-mile course in 18 minutes, 15.53 seconds.
Kayak sprint: Mike Dawson of New Zealand blazed the Gore Creek downriver race course in 15:38.34 to win. Faux finished first among the women in 16:23.21, two days after claiming the steep creek title on Class V Homestake Creek.
More coverage from Chris Freud writing for the Vail Daily. From the article:
The traditional judging area on the kayaker’s right was underwater. There were numerous course holds for large logs entering the hole, including a entire tree stump. And softballs hit from Ford Park are probably in Grand Junction by now. “The river was amazingly high,” Teva kayaking queen Emily Jackson said. “I’ve been here — what — six, seven years now, and never have I seen water this insane.”
“My whole plan basically went out the window because it was a new wave,” Buena Vista’s Dustin Urban said. But when all was said in done, you can pump the entire Pacific Ocean into the Gore and it won’t matter. Jackson owns the Gore and got her sixth-straight women’s win with a clutch third and final ride, while Urban won his second men’s crown in three years…
With high water, the freestyle finals became a completely different ball game. With the help of the bladders, the creek was rolling at 1,400 cubic feet per square inch (CFS) at the beginning of the women’s competition. A mere 45 minutes later, it was at 1,580 CFS for the men.