Update from USGS on MCWD, Ormat

By Deb Murphy

Earlier this week, we reported on the Mammoth Community Water District’s efforts to take a second look at environmental documents and the assumption of an impermeable barrier between the district’s water source and the deeper reservoir tapped by Ormat Technologies’ Casa Diablo IV project.

District general manager Patrick Hayes maintains new data from U.S. Geological Survey call into question that barrier; Ormat’s Paul Thomsen called that data inadequate. In response to our inquiry, the USGS reminded us of the impending government shutdown.

The shutdown was short-lived and we received the following statement from Eric Reichard, the director for the USGS California Water Science Center:

“The U.S. Geological Survey has conducted groundwater monitoring in the Mammoth Lakes area for over 30 years, and has regularly shared preliminary data and analyses with technical working groups. 

This has included water-quality data presented to the Long Valley Hydrologic Advisory Committee (LVHAC) and preliminary water level data presented at the November 1, 2017, meeting of the Groundwater Monitoring and Response Plan (GMRP) work-group. 

The USGS stands by the integrity of its data. However, the data presented at these meetings –and referred to in recent news articles –  have not yet undergone formal analysis following our rigorous scientific review procedures. These procedures ensure that when our science is formally released to the public, it is unbiased and reliable.  Given the high interest in this subject, the USGS is working to complete such an analysis, and make public an accompanying report.” 

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One Response to Update from USGS on MCWD, Ormat

  1. Philip Anaya January 26, 2018 at 10:02 am #

    While the science of hydrology has made great advances it affords a small vision of what is actually occurring underground in relation to what is seen in surface flow. In all the geologic times and into the modern day of the Eastern Sierra there is the fact that there are intrusions , uplift , subsidence, erosional and glacial deposition and faults from earthquakes and more. The concept that there are impermeable barriers that are not intersected by earth forces is most probably and logically a myth. DWP makes a claim of impermeable barriers and wants to draw waters from so called deeper aquifers so as not effect the so called shallow aquifers and the surface vegetation in the Owens Valley. Even an ancient lake, long buried by erosional deposition, it’s semi impermeable layers has it’s margins, it’s ancient shoreline that has a varied degree of permeability. These itinerant geologic structures may limit permeability to some extent but groundwaters in the deeper regions of an aquifer come from somewhere . Gravity is a great force and infiltration is both a horizontal and a vertical process. Between the levels of aquifer regions especially in the Eastern Sierra there is an active conveyance occurring . Ormat and the DWP both need to become more concerned with the issues of local domestic water supply including both the sustainability of the water table and the quality of the water in that aquifer.


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