Establishing a “water budget” in a mountain community is not a simple task.

That’s the message Steven Webb of the North Carolina Division of Water Resources brought to members of the Cashiers Community Water Council at a Jan. 11 meeting.

Establishing a water budget falls within CCWC’s mission, which is “to meet and maintain the needs of the Cashiers Community for environmentally safe waste water treatment and potable water supplies.”
Simply stated, a water budget means determining how much water is available to the community at a sustainable yield. Simple to say, not so simple to calculate, especially in the mountains of Western North Carolina, says Webb.

Mountain aquifers are quite different from those in the piedmont and coastal plain, Webb explained. The latter two are usually large areas of porous materials like sand or limestone. These materials act like sponges and are able to absorb and hold large quantities of water.

The aquifer that Cashiers has to draw from is made from fractured bedrock. Granite is not a porous surface, and many of the fractures may be no more than an inch or so wide, according to Webb.

Webb said that the usable water is called “recharge.” Recharge is that portion of precipitation that makes it into the aquifer. Here in the mountains, a large portion of the precipitation quickly runs off into streams, rivers and lakes. In the summer, much of the rainfall is utilized by plants. The icicles clinging to the mountainsides are made from precipitation that is not making it back into the aquifer, Webb said.

Webb recommended that the CCWC hire a hydrological consultant to help them establish a water budget.

“I will try to get as much background data as possible so that when a consultant comes in the CCWC doesn’t have to spend a lot of money to get them up to speed,” Webb said.

He suggested that the group meet with a few hydrological companies and get some estimates of study costs.

“I would not be surprised if the cost ran between $100,000 and $150,000,” Webb said.

Webb said grants from organizations like the North Carolina Rural Center may be available. “I would advise them to shake every tree they can,” he said.

The study should include an entire year, Webb said, “to see seasonal cycles in water levels and the difference in usage between winter and summer.”

It may be possible, within the water budget, to pump more water than was recharging during the summer, Webb explained, if the aquifer could recharge over the winter.

Issues such as these are “where consultants are going to earn their money,” Webb said.

“In a couple of days, I could tell them where their best bets are for finding producing wells, but it will be up to the consultants to determine sustainable yield,” Webb said.

Webb GPSed eight wells on the 12th and said that he would be back to GPS more and map out where the best fractures are. Webb said that from topo maps, it appeared that there were, “a load of fractures near Sapphire.”

Because of the nature of an aquifer of fractured bedrock, Webb said water may be found in isolated fractures. “It could turn into a management issue -- who’s going to get water, from where?” he said.
“A community water system may be one of the things they have to look at,” Webb said.

Bud Smith, co-chair of CCWC’s Well and Water Resources Committee, said that he felt confident that the CCWC would follow Webb’s recommendations and hire a hydrological consultant.

Webb said that he would serve as professional peer review regarding any study and assist with interpretation if needed.

 

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