July 11, 2009

Beginning in June, the U.S. Geological Survey began to sample some 60 wells around the North Coast, scouting for contaminants and hoping to learn more about the groundwater in the region.

The state started the effort, but funds ran dry like they did for so many other programs as the budget crisis deepened. In May, USGS provided the funding and started the study on the North Coast, looking to tap domestic and public wells, and irrigation and stock wells.

The samples will be analyzed for even small levels of volatile organic compounds, pesticides, microorganisms and radioactivity. The study also aims to put an age on the water withdrawn from the ground, in an effort to figure out how aquifers are recharged, said USGS hydrologist Jennifer Shelton.

”We want to be able to know where that water is coming from,” Shelton said.

The state's program, the Groundwater Ambient Monitoring and Assessment program, is now being funded by the USGS's National Water Quality Assessment program. The federal program tracks water quality in streams and aquifers across the country in an effort to understand how human use affects those sources.

There is virtually no regulation of groundwater pumping in California, and that can have dramatic effects. For example, the state Department of Water Resources recently voiced grave concerns over the sinking of parts of the California Aqueduct -- which supplies water to millions in Southern California -- due to excessive agricultural groundwater pumping in the Central Valley.

Local river advocate Denver Nelson said groundwater problems are also emerging on the Mattole, South Fork of the Eel and Upper Klamath rivers. Groundwater is essential to surface flows, drinking water and water for salmon and other fish, Nelson said, and even in a temperate rain forest like the Humboldt County region shortages occur.

”I think it's the most important aspect of California's water problems,” Nelson said.

Nelson said a groundwater ordinance needs to be considered to prevent withdrawal of more groundwater than can be replenished by rain.

The Humboldt County General Plan update touches on the importance of groundwater. It points out that some 80 percent of the area's river flows occur from November to March and totals 23 million acre feet. But the county's total potential groundwater yield, it reads, is only about 100,000 acre feet, enough to supply roughly 100,000 homes in a year.

”Potential concerns are saltwater intrusion in coastal areas and the effects of groundwater withdrawal on streams that rely on groundwater recharge to sustain flows during the dry season,” the plan reads.

The data from the USGS study may help manage groundwater resources in the future, Shelton said.

IF YOU GO:

What: USGS groundwater sampling program meeting

When: July 15 at 1 p.m.

Where: The Humboldt Bay Municipal Water District in Eureka