Experts: Thinning Forests Could Help Increase Ground Water Supply

TUOLUMNE COUNTY (CBS13) - Officials with the U.S. Forest Service say there are too many trees in the Sierra, creating a major fire hazard and sucking up much-needed water.

Some researchers say cutting down more trees could help ease California's water problems.

In a rural piece of forest in Tuoloumne County, an important experiment is underway that could influence California's future of fire and water.

UC Merced graduate student Michael Pickard and hydrology professor Roger Bales monitor a group of 15 "nodes" that record snowpack, snow melt and soil moisture.

"Think of the precipitation coming in leaves either going back to the atmosphere or down as runoff," said Bales.

Bales says we could be getting more runoff -- more ground water -- if we thinned our forests. The extra trees take extra water, meaning less water makes its way into our groundwater supply.

"This is a forest that is a product of the fire-suppression policies that have been imposed by the federal government over the past 100 years. It's very dense," he said.

You can see the difference between a forest cleared of extra trees and brush and a plot that hasn't been touched in nearly a century. Bales and his team estimate thinning Sierra forests could provide 10 to 20 percent additional runoff -- more water for us.

"Is there a way for the forest service to thin and pull out the same amount of trees, but leave the existing trees in certain patterns that prolong our snowpack and help us accumulate more," said Bales.

The team is measuring areas thinned in even and random patterns to see where the most water is gained.

"If we deployed ten of these clusters of 15 around this river basin, we could really nail the water balance in this river basin," he said.

Bales says the state is considering investing in more of those data-gathering nodes to spread throughout a greater portion of the Sierra Nevada.

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