Homeowners in the Wood River Valley and in the areas surrounding the Little Wood River near Carey and downstream need to be aware of the significant possibility for flooding later this spring, officials at two flood preparedness workshops held in Hailey said Wednesday.
Blaine County sponsored the workshops—one held during the day for local public works, first responders and other government employees, the other held at night for elected officials. Invited to speak during the meetings were Herb Bessey from the Army Corps of Engineers and Terry Bingham from the Idaho Bureau of Homeland Security. Chuck Turner, Blaine County's disaster services coordinator, was also on hand to offer his advice.
The primary purpose of the workshops was to brief local officials on flood fight operations in terms of forecasting, safety concerns and how to properly manage those efforts.
Although reports released earlier this year suggested that the chances of the Wood River Valley flooding this spring were quite low, the above-average snowpack in the area would suggest otherwise, Turner said.
Turner pointed to the approximately 140 to 160 percent of average snow water content in the area's snowpack as a reason to be concerned.
"The odds of high water are extremely great," he said.
Another point of concern is the extent of the local snowpack, Turner said. This year, not only are the depths of the snowpack greater at higher elevations, but the total area covered by snow at lower elevations is much greater right now than in comparison to normal snow years, he said.
Nearly twice as much snow water content—the measure most important to evaluating the likelihood for flooding—currently exists on the ground in comparison to the past several years.
What this all adds up to is a significant amount of snow still waiting to melt in the Big Wood and Little Wood river drainages, Turner said.
"We've probably got four to five times the total surface area of snow," he said. "It's just about double all the way around, and it's over a bigger surface area."
Officials also discussed the illegality of making alterations to a river channel to protect one's property. Enforcing laws that forbid such work and protect against the negative consequences such actions can have on downstream landowners can be extremely difficult, the officials warned.
Landowners don't have the right to take actions that will negatively affect their neighbors, Bessey said. "They should be only trying to protect their immediate home and not trying to redirect the river," he said. "Anything you do on one side of the river will have impacts on the other side of the river."
Towards the end of the meeting, discussions centered on the possibility of paying for overflights up and down the Big Wood River to make sure landowners aren't illegally altering the river.
Bessey, who helped coordinate the resources of government agencies in Camas, Gooding and Lincoln counties during the recent flooding episode, said the response there was well organized. Still, he added, "it's a small-scale operation compared to what you folks are staring down the gun."
The bottom line, officials agreed, is landowners will for the most part be responsible for the protection of their own properties. Local city and county governments typically only work to protect public property and important infrastructure such as roads and bridges.
Safety concerns when the Big Wood River is flowing high and fast were also discussed.
Turner noted that the difference between the Big Wood River running at 3 feet and 6 feet, the official flood stage, is significant. When the Big Wood River is measured at 3 feet at the water gauge in Hailey the river is only running at 1,000 cubic feet per second (cfs), he said. At 6 feet, the Big Wood is running at 4,000 cfs, Turner said.
Local residents need to keep children and pets away from the river when it's running at such high levels, he said.
"That second 3 feet has three times as much volume," Turner said.
Forecasting floods and determining whether to initiate a flood watch or a flood warning comes down to a number of factors, Bingham said. Those include precipitation reports, soil conditions (how saturated the ground is), snow conditions and temperature readings.
Most years, Magic Reservoir fills with flows from Camas Creek and its level is maintained by the Big Wood River, Bingham said. "This year it looks they're going to run together," he said.
Local residents need to realize that the Wood River Valley still has yet to see the majority of its runoff, Bingham said. Flood peak on the Big Wood River is generally from mid-May to late May, he said.
