For more than 60 years, we have safely owned, operated, and maintained reservoirs and dams for the benefit of our community. We operate five reservoirs: San Joaquin, Sand Canyon, Syphon, Rattlesnake, and Santiago Creek. We also operate a small, non-jurisdictional dam in Harding Canyon.
We continually monitor, inspect, and maintain our dams and reservoirs. But that’s not all. Our engineers and dam safety experts follow a state-of-the-art Dam Safety Program, which exceeds all current state standards. This program combines traditional safety standards with a modern Risk-Informed Decision-Making process, known as RIDM. Our Dam Safety Program builds on industry best practices to ensure that our dams and reservoirs will always be safe.
IRWD reservoirs near residential communities receive very little or no water from rivers or streams. That means we can completely control the flow of water in and out.
For reservoirs that do receive water from rivers or streams, we can manage the water level during heavy rainfall by safely releasing water into our recycled water system, downstream creeks or open spaces.
Reservoirs and dams increase our community’s self-reliance by safely storing local water. This protects our community against future droughts and helps preserve low customer rates. Water from these reservoirs is also used by fire crews to put out wildfires.
All five of our jurisdictional dams use engineered earthen embankment dams — the most common type of dam found throughout California. Compacted earth and rock materials are used for these structures because they’re proven to be resilient and self-healing in earthquakes. These types of dams consistently have strong safety records, and they blend with the natural environment.
In California, dams are regulated by the California Department of Water Resources Division of Safety of Dams (DSOD). DSOD annually inspects the five dams under their jurisdiction including San Joaquin Dam, Sand Canyon Dam, Syphon Dam, Rattlesnake Dam and Santiago Creek Dam. DSOD provides a safety rating for each of IRWD’s dams based on several factors including the height of the dam and the storage capacity of the reservoir. DSOD and IRWD have concluded that all IRWD dams are safe for continued use.
In addition to regular inspections, measurements of drain flows, monitoring wells and piezometers are routinely recorded to understand the historic and current performance of the dams and potential changes.
DSOD also reviews the stability of dams and their major facilities in light of improved design approaches and requirements, as well as new findings regarding earthquake hazards and hydrologic estimates in California.
Survey monuments are also surveyed annually to measure precise locations of monuments and identify potential movement of the embankment.
IRWD retains a team of engineers and dam safety experts who have been nationally recognized as some of the best in the field, including geotechnical consultants who specialize in dams. We conduct regular additional inspections for close monitoring of the critical water resource facilities. IRWD staff visually inspect all five dams daily.
Our commitment to the community includes developing and maintaining an Emergency Action Plan for each of our jurisdictional dams. In the highly unlikely event of an emergency, residents in the area would be notified and directed to helpful resources. IRWD works with regulators at the state level and coordinates with local public safety personnel to develop and maintain Emergency Action Plans.
Learn more about the Dam Safety Program, or ask questions about a reservoir or dam in your area.
