The project would create two large earthen dams and two smaller dams, the tallest being 260 feet high, which would be located just west of I-5 and the community of Patterson, home to 25,000 people. The other would be 153 feet high about 1.5 miles along Del Puerto Canyon Road
According to the draft Environmental Impact Report or dEIR available at: https://delpuertocanyonreservoir.com/assets/pdf/reports/Del-Puerto-Canyon-Reservoir-Draft-EIR.pdf, should the south saddle dam along Del Puerto Canyon road fail, the city of Patterson north of Sperry Avenue, would be inundated within minutes by up to ten feet of water all the way to the San Joaquin River raising it over ten feet. If a dam fails, the water will traverse over, and likely destroy the two nearby main artery aqueducts - furthering the devastation and causing a real water threat for famers.
Simulated view of the main earthen dam across Del Puerto Creek beside I-5 north of the Patterson Exit.
The inundation zone contains seven active landslides. Once water fills the reservoir it will act like a lubricant, and create a possible seiche wave which could overtop the dam. Geologists have spoken to this point.
There are two active faults twenty miles away from the reservoir. Seismologists predict a high chance of a major earthquake in this area within ten years.
This view illustrates the sheer size of the proposed reservoir in comparison to the community, and in location. The blue highlights indicate the current flood zones north of Sperry Road.
The image on the left shows slumping of the soil. This slumping is actually an active landslide.