Water managers prepare for heavy spring runoff
March 20, 2014
With the average snowpack for the area already at 140 percent of normal with two more months of possible precipitation ahead, area water mangers are predicting spring runoff will fill local reservoirs.
While it is too early to say whether this year’s above normal snowpack will bring the area out of the long-term drought that has plagued much of the western states since 2000, the increased snowmelt could put the area at risk of flooding.
Water managers that operate within Grand County have already begun to plan for the increased amount of spring runoff, though filling the reservoirs while not allowing them to spill is more of an art than a science, according to Brian Werner a public information officer with Northern Water.
Water managers look to fill their reservoirs without allowing them to spill while at the same time helping to manage stream flows to prevent flooding. The art comes from releasing only enough water from reservoirs before the snow melts that can be replaced with spring runoff.
So calculating the amount of snowpack and the water that will come down as runoff from that snowpack is paramount for water managers.
Preemptively releasing water and actively managing water throughout the runoff season helps to reduce the risk of flooding.
Snowpack levels are slightly higher this year than they were at this time during 2011, the highest runoff year to date, according to Werner.
In 2011 the Colorado river was above its water line and considered flooded for three months, according to Mark Volt, district conservationist for the USDA Natural Resource Conservation Service Kremmling Field Office.
While water managers will work to divert water during runoff to help alleviate the risk of flooding, they can only take as much water to fill their reservoirs.
There are three water operators in Grand County; Denver Water, Northern Water, and the Colorado River District. All three expect to fill the reservoirs they operate in the area.
Denver Water will divert water through the Moffat Tunnel system during peak runoff times to both add water to their reservoir system that serves the Front Range and to help ensure the Fraser Valley doesn’t experience flooding.
The risk of flooding depends heavily on the weather during the coming months and if a spell of hot weather where to sweep through the area while there were still high levels of snow on the ground, the risk of flooding could increase, according to Stacy Chesney, manager of media relations for Denver Water.
Earlier runoff seasons are becoming more normal due to recent changes in weather, which makes managing water an ever-changing chess game with Mother Nature.
Looking to the future
“We have been experiencing more climate uncertainty and weather extremes,” Chesney said in an email interview. “In 2013, for example, we went from severe drought to unprecedented rain in a matter of months.”
Chesney is referring to rain storms that swept through the area in September of last year that caused devastating flooding along the Front Range.
Those rains, while causing flooding along the Front Range, also helped to fill the reservoirs in the region.
Denver Water reservoirs are currently 91 percent full, according to Chesney. Normally those reservoirs are only 80 percent full at this time of year and last year around this time, when the area was under drought conditions, their reservoirs were only 71 percent full.
The combination of above-normal snowpack and current reservoir levels means Denver Water is expecting to completely fill their reservoirs this year.
The extreme between wetter wet years and drier dry years makes it difficult for water mangers to plan ahead.
Water managers need to store as much water as they can during wet years, such as the current year, in order to last through the dry years. For example, 2012 was the worst runoff years on record, according to Jim Pokrandt, communications manager for the Colorado River District, which operates Wolford Mountain Reservoir. Luckily, the reservoir levels were healthy from 2011, making lasting through the dry months of 2012 more manageable.
“Our goal is to plan for the future as best we, and we are committed to working with the communities in which we have facilities to operate our system in a way that offers the most benefit to stakeholders and the environment,” Cheseny said.
“We are seeing extremes on both sides, wet and dry,” Werner said. “If that is what mother nature is continuing to do, we better be ready.
Reid Tulley can be reached at 970-887-3334