Geological Survey drilling Fallon aquifer

FALLON - As if arsenic and leukemia weren't enough, the main source of water for Fallon may be in danger of salting up.

The water comes from a rock formation known as basalt, a mushroom-shaped remnant of a 1 million-year-old volcano which peeks above the surface northeast of the city.

Most of the water for Fallon and the Naval Air Station comes from the aquifer within the basalt. As the level is dropping, the water is getting saltier.

The U.S. Geological Survey is drilling two deep wells - one 1,000 feet, the other 500 feet - to find out just how much water is in the basalt and to test its quality.

"That's going to be one of the more interesting holes I've ever dug," said survey hydrologist Doug Maurer. "It is terra incognito down there.

The basalt is what is left of a volcanic cone, buried nearly to the top in sediments deposited by the Carson River.

It is shaped like a mushroom and is riddled with holes that contain the water.

"It's like Swiss cheese down there," Maurer said. "Nobody has drilled very far down there. We don't know how deep it goes. After 50 or 60 feet it could be saline."

Maurer said Geological Survey scientists hope to find out if the aquifer is being drawn down by excess pumping.

"As they are increasing pumpage from the aquifer they are decreasing the levels and the chloride concentrations are going up," Maurer said.

The aquifer below Fallon consists of essentially two layers of water, one saline and one fresh.

Because fresh water is lighter than salt water, it caps the deeper saline aquifer.

But if pumping the aquifer is drawing down the fresh water, salt water may be rising to fill the void.

"It's kind of amazing that the Navy and Fallon don't know how much potable water is down there," he said. "Even though it is high in arsenic, it is their sole source of water."

Wells presently go down only about 50 feet or 60 feet.

Work on drilling the wells will begin today and should take all week. Maurer said drillers will have to borrow drilling techniques from miners in order to complete the wells because the material is so permeable it is difficult to drill through.

"Once we install these wells, we'll find out where the saline layer begins and put a well right above that to see if as pumping continues, it is inducing an upward flow of more saline water."

However, Maurer cautioned, the salt may be coming from around the sides of the basalt, where it and the shallower aquifers meet.

Maurer said some of the basalt wells are also being tested for water content by scientists looking for the source of a cluster of leukemia among children who have lived in Fallon.

"Those poor people out there are having a bad year," he said. "A well driller I talked to said he usually has plenty of work but is going to California to drill."

Slightly more than half of the 120 wells have been tested for both artificial and natural elements that might be connected to the leukemia cluster.

Fourteen Fallon children have been diagnosed with some form of leukemia over the past year.

One child, 10-year-old Adam Jernee, died of the disease in June.

Testing the wells is just one of several activities going on to try and track down the source of the cluster.

The Centers for Disease Control will open a field office in Fallon on Wednesday, where researchers will be taking blood, DNA and urine from volunteers.

Researchers will also conduct a random phone survey.

Unrelated the leukemia, researchers say, is high levels of arsenic in Fallon, where water has tested at 100 parts per billion, among the highest levels in the country.

The city is planning a $10 million treatment center to reduce the amount of arsenic in the water to meet federal standards.