Warm Water in Shallow Monitoring Wells Could Threaten Local Water Supply
The Mammoth Community Water District (MCWD), a water and wastewater utility service, has shared its results from two shallow monitoring wells that were drilled by the United States Geological Survey (USGS). It found hot water in the shallow aquifer, suggesting potential connectivity between the groundwater basin and the geothermal zone below. Geothermal pumping provided by Ormat Technologies' Casa Diablo IV Geothermal Development Project may threaten local water supplies with increased soil temperatures, gas releases, and tree deaths connected to the town of Mammoth Lakes.
MCWD has raised concerns in the past, especially about the impacts of geothermal expansion and the district’s water supply during drought conditions. Temperatures have been recorded as high as 210 degrees Fahrenheit and at least one well has shown traces of chemicals associated with geothermal water. Therefore, the decision was made to continue litigation challenging the adequacy of Ormat's environmental analysis.
"These preliminary findings reinforce the District's ongoing concerns over geothermal expansion," says MCWD Board President Tom Smith. "If, as the findings suggest, Ormat's operations are increasing soil temperatures and degrading the environment, then we will continue fighting for a more thorough analysis and additional monitoring and mitigation to protect our vital resources."
Ormat’s project is set to double geothermal pumping near Mammoth Lakes, even with an inadequate environmental analysis and a lack of monitoring and mitigation plans to protect groundwater resources. The community is almost entirely dependent on groundwater, due to the unprecedented drought, which makes an examination of how geothermal projects operate especially important in regards to ensuring long-term water availability and quality.
"The early analysis by USGS suggests that more careful study is needed before expanding geothermal energy use," says Smith. "For our district, geothermal production must not come at the cost of our critical water supplies and environmental resources."
Source: Modern Pumping Today