Hunting for Big Sky’s water supply
A delicate aquifer requiring rest could create growing pains
Beneath the surface is one of this community’s – and the world’s – most valuable resources: groundwater. National Geographic research has shown that only 2.5 percent of the nearly 70 percent of the water covering the world is fresh water. Less than one percent of that fresh water is accessible, since much is trapped in snowfields and glaciers.
“In essence, only 0.007 percent of the planet's water is available to fuel and feed its 6.8 billion people,” the Nat Geo article states, highlighting the fact that population growth is straining the world’s water supply.
The story does not differ in Big Sky. It was revealed at the Big Sky Water and Sewer District board meeting on December 19 that more water is needed. A recent study showed the delicate aquifer on the mountain requires nine months of recharge for every three months of use.
Board members discussed the complicated issue at length to try and hash out a plan, tossing around copious amounts of complicated data and trade lingo.
It’s the stuff touched upon in junior high science classes, but also an insanely complex science gaining ground in importance as potable water becomes an increasingly hot commodity. The aquifer on the mountain is even more valuable due to a longstanding and lifelong agreement between the BSW&SD and Big Sky Resort: a portion of that water is used to make snow.
Experts had high hopes for two wells which were drilled on the mountain years ago, but recent studies show that neither is producing the amount of water needed or anticipated.
The larger one can initially produce a significant volume of water, but unsustainably.
BSW&SD board members made it clear they want to protect the aquifer and will likely be requesting permission to do exploratory drilling to find other water sources come summer. The science behind that stance was explained on the USGS website: Precipitation eventually adds water – or recharge –into the porous rock of the aquifer. The rate of recharge differs for all aquifers and has to be taken into account when pumping water from a well.
“Pumping too much water too fast draws down the water in the aquifer and eventually causes a well to yield less and less water and even run dry. In fact, pumping your well too much can even cause your neighbor's well to run dry if you both are pumping from the same aquifer,” the USGS states on its website.
The level of the water table can change naturally from a number of factors: weather cycles, precipitation patterns, geologic changes and changes to a streamflow. Human influence comes into play with an increase in impervious surfaces like parking lots and construction which cover earth that had previously allowed for water to seep into the water table and aquifer. Also, the pumping of wells – and the rate with which they are pumped – can cause dire consequences for the short and sometimes long-term state of the aquifer.
When water is withdrawn from an aquifer by wells faster than it can be replenished by infiltration from the surface or by streams, the water table can lower.
The USGS website also addressed water table issues, stating: “Depending on geologic and hydrologic conditions of the aquifer, the impact on the level of the water table can be short-lived or last for decades, and it can fall a small amount or many hundreds of feet. Excessive pumping can lower the water table so much that the wells no longer supply water—they can ‘go dry.’”
“We can manage just fine right now,” BSW&SD President Ron Edwards stated at the December board meeting, citing the main concern as continuing summer growth. “Part of the reason for looking up at the mountain is we can move it down to the meadow. For public water wells, you start with 100 gallons a minute; decent yield and good water quality.”
The water the district is seeking on the mountain will potentially become the bulk of the water which will accommodate the influx in development for which all of Big Sky is primed.
“We need to find additional water sources up there,” board member Mike DuCuennois said regarding the summertime water level drop seen recently in Lake Levinsky. “I’d rather find some of this through this exploration. It was an odd year. I’ve never seen [Lake Levinsky] drop like it did... I’m not concerned with the aesthetics.”
DuCuennois continued his thoughts, “The aesthetics are not even on my radar right now. If people want Lake Levinsky refilled, tell them no: We can’t.”
Board members agreed on the value of both potable water and snowmaking to the Big Sky community and several spoke to discovering a win-win situation.
While there were some rumblings at the meeting of trying to renegotiate the water use agreement between the district and Big Sky Resort, Edwards found that talk hasty. The district is on the hunt for water and he is confident it is up there. It’s just a matter of finding it.