We work closely with dam owners to identify and correct potential problems before they become serious. If we find a potentially unsafe condition, we work with the dam owner to address and remedy the condition in a timely manner. When necessary, we may immediately employ any remedial means necessary to protect life and property, or we may impose a reservoir restriction limiting the water surface to a level that is judged safe. We may also direct the dam owner to implement their emergency action plan (EAP).
DSOD established the Spillway Re-evaluation Program in 2017 to assess dam appurtenant structures, including spillways, to confirm they meet minimum safety standards. This is an on-going screening process and re-evaluation of spillways at dams, starting with these that potentially pose the highest hazard. This evaluation includes the assessment of the spillway’s design and construction and geologic attributes while concurrently reviewing the dam owner’s maintenance and inspection program, the spillway’s historical performance, and any previous spillway repairs. DSOD is working closely with dam owners to expedite the development of the required assessments and restore any known areas of disrepair.
| Street Address:
Sharon K. Tapia, Chief
Division of Safety of Dams
2200 X Street, Suite 200
Sacramento, California 95818
|Post Office Box Address:
Sharon K. Tapia, Chief
Division of Safety of Dams
Post Office Box 942836
Sacramento, California 94236-0001
You should always contact the respective Area or Regional Engineer (PDF) for a determination as to whether an application will be required for any work to be performed on a dam or its appurtenances. As a general guideline, an application will be required if the work entails more than routine maintenance.
We don’t recommend any specific individual or firm, but we can provide names of consultants that have worked, or are working on nearby projects. We also recommend that you check out the following organizations and websites:
Phone: 888-285-NSPE (6773)
Currently, our files are only available to dam owners and their designated representatives. For further information or to set up an appointment to review our files, contact our file administrator at (916) 227-4695. Our office is located at 2200 X Street, Suite 200, Sacramento, CA 95818.
Senate Bill 92, a newly enacted law signed by Governor Brown on June 27, 2017, requires DWR to make approved inundation maps available to the public. As dam owner's submit inundation maps to us, they are reviewed and approved before they are made available to the public. Available maps are located on our Inundation Maps page. You may also contact your local emergency management office using the California Office of Emergency Services website for information on dam inundation areas, or you can contact the dam owner.
Yes, our guidelines are summarized below:
- For reservoirs that impound 5,000 acre-feet of water or less, the outlet system should be capable of draining half of the reservoir capacity in 7 or 10 days and full contents within 20 or 30 days, respectively, depending on factors such as downstream and seismic hazard, dam construction methods and age, known deficiencies, and type of dam; as determined by the Division.
- For reservoirs that impound over 5,000 acre-feet of water, the outlet system should be capable of lowering the maximum storage depth by 10 percent within 7 or 10 days and draining its full contents within 90 or 120 days, respectively, depending on factors such as downstream and seismic hazard, dam construction methods and age, known deficiencies, and type of dam; as determined by the Division.
These guidelines are evaluated on a case-by-case basis, particularly for the very large reservoirs that are in excess of 100,000 acre-feet.
A typical field investigation should:
- Seek to identify geologic hazards that could adversely affect the project.
- Characterize the engineering properties of available earth and rock construction materials.
- Characterize the strength and permeability of the dam, spillway, and outlet foundations.
Since each site and project is unique, exploration plans should be submitted to DSOD beforehand for review. DSOD should also be given the opportunity to observe the site conditions firsthand during exploration.
A typical field investigation program includes understanding the geology of the site through geologic mapping, air photo analysis, test pits, and borings. The engineering properties of embankment and foundation soils are generally evaluated by sampling and laboratory testing, and in field testing such as in-place density, penetration resistance, and permeability testing. Geophysical techniques, such as seismic refraction and shear wave velocity testing are sometimes used. Core drilling and water pressure testing may be required for rock foundations. A phased investigation is often the most effective way to evaluate the geologic conditions and engineering properties of a site.
Our policy requires that dam owners regularly exercise (operate) their outlets in order to demonstrate the ability to draw down the reservoir during an emergency. Outlet controls should be fully exercised at least annually and, in our presence, every three years. Experience has proven that regular exercising of gates/valves helps prevent major maintenance problems from developing and is therefore part of a good maintenance program.
We do not operate the outlet controls themselves nor order their operation during routine inspections. It's the responsibility of the dam owner to develop appropriate plans and make the necessary arrangements when dealing with difficult outlet situations. We accommodate reasonable delays in exercising of outlets so owners have time to complete proper planning, coordinate with other agencies, and perform maintenance and repairs, if necessary.
Dam owners should maintain a log detailing all operation and maintenance activities for their outlet system.
- Dams Within Jurisdiction of the State of California (Alphabetically by County)
- Dams Within Jurisdiction of the State of California (Alphabetically by Name)
- DSOD Dam Rating Information and FAQs
- DSOD Dam Rating List FAQs
- Jurisdictional Dams Listed Alphabetically by Reservoir Name
- Jurisdictional Dams Receiving Additional Spillway Re-evaluation
- Lake Oroville Main Spillway Ready for Rainy Season
- Lake Oroville Spillways Construction Updates 11/30/2017
- DWR Convenes Inaugural Community-Led Meeting for Oroville Dam Safety Comprehensive Needs Assessment
- DWR Meets Nov. 1 Public Safety Milestone
- Lake Perris Trail Opens as Reservoir Nears Full Capacity