Above: Helix’s R.M. Levy Water Treatment Plant sits across the street from Chet Harritt Dam and Lake Jennings, where we store imported water from the Colorado River and the State Water Project.
The damaged spillway at Oroville Dam, which occurred earlier this year in northern California, sparked concern about the integrity and safety of aging infrastructure nationwide.
Those concerns are front and center again this week during Infrastructure Week 2017, a national campaign created to raise awareness about the importance of improving and maintaining local, state and national infrastructure – including critical water infrastructure like dams.
Here at Helix Water District, we own and operate two earthen fill dams: the dam at Lake Cuyamaca captures and stores local runoff and the dam at Lake Jennings stores imported water from the Colorado River and Northern California. Unlike Oroville Dam, Helix’s dams do not serve flood control purposes.
Helix’s dams are inspected regularly by Helix staff and annually by the State of California, Department of Water Resources, Division of Safety of Dams. Helix is in full compliance with all requirements of the Division of Safety of Dams and maintains an Emergency Operations Plan in the event of emergencies involving one of the dams.
Helix staff regularly inspect and maintain dam infrastructure, including spillways, outlet towers and the dams themselves. During weekly visual inspections, staff checks for cracks, settling, rodent intrusion, brush growth and abutment integrity, all things that can undermine a dam’s integrity.
Regular maintenance includes clearing brush and woody vegetation off of the dams and abutments, and operating all mechanical devices such as outlet valves to ensure they remain in good working order.
Chet Harritt Dam at Lake Jennings is equipped with an underdrain system that allows the measurement of water flow. If water flow becomes excessive, alarms activate automatically, notifying staff immediately. At both dams, monitoring well measurements are taken on a weekly basis and surveys are conducted annually to verify dimensions.
Finally, in the event of an earthquake of magnitude 5 or greater with an epicenter within specified distances from the dam, survey and engineering crews will inspect the dam to ensure its integrity and dimension.