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Where does all the traction sand go on Vail Pass?
The arrival of snow means traffic on I-70 over Vail Pass bustles with skiers and visitors to and from the Front Range, with cars braving storms and bumper-to-bumper traffic in search of a powder day. Without the help of traction sand or de-icers, our ability to constantly travel across the state would not be possible.
Roughly 5,000 tons of traction sand are laid down on Vail Pass each year, but where does all that sand end up? Originating from aggregate mines from the Western Slope and stored in the igloo tent atop Vail Pass, the sand is sprinkled along the highway corridor to ensure safer travel along the pass. Colorado Department of Transportation (CDOT) enlists contractors each year to come through in the late summer with vacuum trucks to suck up the remaining sand on the road ways and median. The used sand is then brought down to the berms that line the north side of the highway in East Vail. Sand is also flushed by rain and snow over the embankments and carried into sediment-catch basins or into Black Gore Creek, which closely parallels about 10 miles of the interstate from its headwaters at Vail Pass to the confluence of Gore Creek.
Extensive sediment loading to Black Gore Creek from nearly three decades of I-70 operations have severely impaired the stream, resulting in losses of aquatic habitat, impacts to wetlands and an overall reduction in water quality. In addition, the accumulation of sediment in Black Lakes near Vail Pass encroaches upon the storage capacity of water supply reservoirs that serve Vail and are used to maintain instream flows.
Black Gore Creek Steering Committee’s Efforts
Since 1997, the Black Gore Creek Steering Committee (BGCSC), headed by Eagle River Watershed Council, has worked to mitigate the impacts to Black Gore Creek and the health of its aquatic life. The committee is made up of a number of important partners in the community, including Eagle River Watershed Council, Colorado Department of Transportation, Eagle County, U.S. Forest Service, Town of Vail, Eagle County, Eagle River Water & Sanitation District, Lotic Hydrological, River Restoration, Colorado Parks & Wildlife, Colorado Department of Public Health & Environment, and concerned citizens.
In 2002, Black Gore Creek was listed on the State’s 303(d) list of impaired waters for sediment—which is different than Gore Creek’s more recent listing in 2012 for aquatic life impairment. Although the State has yet to come out with a limit of how much traction sand can enter the creek, CDOT, in collaboration with the other BGCSC partners, has taken great initiative to address these issues over the past 10 years.
To date, CDOT is picking up nearly the same amount of traction sand as they are putting down annually, which has improved since the years when no cleanup occurred, and the basins slowly filled.
Besides capital improvement projects such as repaving the medians and bike path enhancements, one of the most significant improvement projects has been the identification of a long-term maintenance solution for the Basin of Last Resort. A 3-acre section of Black Gore Creek around mile marker 183 on I-70, the Basin is a control structure that traps sediment missed by upstream catch basins. There has been concern with its effectiveness as the basin fills with sediment. In the fall of 2017, construction of a road allowing for easier access to excavate the basin more regularly and efficiently was finalized.
More work is to be done, however, as the goal is to have less sediment reach the Basin of Last Resort in the first place. Through field assessments, mapping activities, and sediment transport modeling, consultants to Eagle River Watershed Council, namely River Restoration and Lotic Hydrological, are working to identify opportunities for capturing traction sand before it leaves the highway corridor and enters the creek.
Traction Sand vs. Mag Chloride
CDOT has also installed sophisticated software in their plowing vehicles that senses how much traction sand or de-icer they should be applying on any given segment of the highway. The increased prevalence of de-icers, commonly referred to as “mag(nesium) chloride,” has been an inevitable outcome from the pressure on CDOT to reduce the amount of traction sand applied. Although very effective at melting snow and preventing ice formation, de-icers aren’t without their downsides. Studies have shown that elevated levels of chloride in rivers can be detrimental to aquatic life. The Watershed Council and CDOT both conduct chloride-loading studies to understand how chloride concentrations differ in Black Gore Creek and Gore Creek and whether they are approaching harmful levels.
“We don’t see the kinds of widespread impairments of the biological communities on Black Gore Creek that you would expect if they were really being negatively impacted by chloride. The health of those communities may be somewhat limited, but they do not meet the Colorado State definition for impairment right now,” reports Seth Mason of Lotic Hydrological. That is not to say that we shouldn’t be concerned about chloride levels in Black Gore Creek. While macroinvertebrate communities in Black Gore Creek may look better than those on Gore Creek through Vail, they may be stressed by elevated chloride concentrations and more vulnerable to other impacts on the creek. While more studies chloride’s effects are needed, the BGCSC is committed to not replacing one pollutant with another.
Related to Gore Creek’s Woes?
With all the recent attention on the Restore the Gore effort surrounding Gore Creek, some long-time locals believe the impacts from Black Gore Creek are at fault. Up until 2012, the State associated high sediment levels automatically with impaired aquatic life. In conducting macroinvertebrate sampling in our watershed, we are finding that aquatic bug scores on Black Gore Creek are healthier than those in the highly developed sections of Gore Creek through Vail. This along with other evidence leads to the belief that stormwater runoff from impervious surfaces in town and the loss of riparian areas along Gore Creek from development are a greater contributor to Gore Creek’s impairments.
The important efforts on Vail Pass have not slowed–in fact CDOT has spent about $7 million since 2013 to clear out the catch basins and sweep our roadways. The Watershed Council will continue the collaborative dialogue and mitigation efforts of the stakeholders to ensure the important progress continues in keeping our waterways healthy and clean.