Lake Tahoe protections harming groundwater?
A $300,000 study is under way to determine whether dozens of water collection basins installed to protect Lake Tahoe’s fading clarity are having an impact on groundwater.
The basins hold melted snow and rain that runs off streets and sidewalks long enough for sand and oil to separate from the water and filter slowly into the ground instead of running directly into the lake.
South Tahoe Public Utility District and the U.S. Forest Service funded the study. The final report is due next fall.
“Definitely MTBE was part of the impetus of this study,” said Ivo Bergsohn, hydrogeologist for the district. “I’m not sure whether it would have happened anyway or not, but because of MTBE it did happen probably a lot sooner.”
Since 1997, 13 of the district’s 34 wells have been tainted by methyl tertiary butyl ether, a gasoline additive now banned in the Lake Tahoe Basin. Treatment systems have revived several of those underground wells, but the onslaught of the fuel additive has led in part to year-round water restrictions for South Shore residents.
The groundwater study, which began in November 2003, is focusing on two basins – one on Eloise Avenue, and one recently constructed on Industrial Way. Different sets of data will be collected during four storms, the time when water washes off the streets and flows into the basins.
“One of the reasons the Eloise basin was selected was that the consultant had quite a bit prior knowledge about it,” Bergsohn said. “And it’s an older basin that caught a lot of stormwater from an industrial section of town.”
– Gregory Crofton can be reached at (530) 542-8045 or by e-mail at firstname.lastname@example.org