An excerpt from a press release; submitted by Shivaugn Alves
After reviewing the draft environmental impact report (dEIR), highly critical comments have been submitted by specialists in their field. Friends of the River’s senior advocate, Ron Stork, joined MJC geologist Garry Hayes and environmental compliance expert, Dr. Tom Williams, expressing concerns about the reservoir.
Garry Hayes noted that the dEIR’s discussion of the possibility of mass wasting (landslide) is wholly inadequate. Debris flows may slide into the reservoir, resulting in a lake tsunami which could exceed the dam height and overtop - seven landslides are within the inundation zone. Hayes is also concerned that the series of faults in the area are poorly studied and understood. A 6.0 earthquake shook the area in 1880, with little documentation. The soft rocks in the area erode and remove most evidence of past earthquakes.
Ron Stork stated that the dEIR provides no geotechnical analysis supporting the conclusion that any landslides would be slow and at a scale that would not form a seiche wave (tsunami) of significant magnitude. Landslides are a known risk for dam failure and a detailed geotechnical evaluation of the stability of any areas susceptible to sliding under reservoir conditions should be done before selecting the dam site. Deferring the necessary geotechnical analysis until after the Water District has approved the environmental review for the site — on the assumption that there will be cost-effective engineering solutions to address this risk — is not a good process and assumes facts that may not prove to be true.
Dr. Tom Williams concurs with Hayes and Stork, stating: The geological formations and current topography are conducive to mass movements and landslides at present and when their lower supporting slumps are wetted. Many landslides are waiting to happen when they get wet. Slides may interfere with the efficient and reasonable storage and operations of the reservoir.