Preparing for El Niño

Keeping You and Your Community Safe

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El Niño preparedness involves a coordinated effort across multiple agencies, including the County of Orange, cities, law enforcement, non-profit organizations, community groups and more.

OC Public Works, OC Sheriff’s Department and the OC Fire Authority work hand-in-hand on storm emergency planning and response to ensure we effectively support each other in order to best protect our communities.

OC Public Works manages over 320 miles of roadways, 380 miles of flood control channels, seven pump stations (that move storm water to larger flood channels) and five dams: Seven Oaks Dam in San Bernardino County (in  collaboration with San Bernardino and Riverside Counties), Villa Park Dam, Harbor View Dam, Peters Canyon Dam and Sulphur Creek Dam.

Managing these facilities, we help maintain the quality of life that county  residents enjoy – by providing safe roadways for drivers, keeping public areas clean and providing flood protection for our communities.  These are all a  major focus of OC Public Works’ efforts before, during and after major rain storms.

Innovation = Increased Efficiency = Effective Preparation

One way OC Public Works remains prepared is through maintaining and  monitoring an advance flood warning system called “ALERT” (Automated Local Evaluation in Real Time), which is a network of rainfall and water level sensors that enables real-time tracking of storms.  The ALERT system: 

  • Features 130 sensors at more than 80 locations throughout the County
  • Measures precipitation, water level in regional flood control channels, temperature, barometric pressure, wind velocity and direction, relative humidity and snow
  • Updates information every eight minutes during storm events and allows OC Public Works to strategically deploy resources where critically needed
  • Is available through the OC Public Works web site at:
  • OC Works smartphone app : The public can also download the “OC Works” smartphone app offered by OC Public Works, where residents can easily report issues or concerns they observe on County roadways or other public areas in unincorporated Orange County. App users also have the ability to submit photos of issues they wish to report.  The OC Works app is available at the App Store or Google Play.

New Tools for Added Community Protection

As added protection measures to prepare for the El Niño storm season, OC Public Works is using two new tools that have been successfully used in the storm-prone southeastern and northeastern United States.

“Tiger Dams” are a quick, versatile and re-usable system that helps provide added flood protection in areas where storm water can rise rapidly during rain events.  The system involves 50-foot sections of water-filled bladders that can be used individually or linked together to form a continuous protective barrier over longer distances. A Tiger Dam section spanning 50-feet can be installed in only a few minutes and can perform the same function as 500 sandbags.

“Muscle Walls” are another efficient tool being used and feature water-filled, heavy-duty plastic barriers that can withstand a high amount of force from excess storm water.

Providing added efficiency, both Tiger Dams and Muscle Walls can be re-used from year to year and storm to storm, and can be installed within very quick timeframes to provide added flood protection where storm water levels may rise.

Both of these additional tools are being used at several locations in Orange County that experienced “over-topping” during rain events in 2010 where storm water rose slightly above the flood channel walls and onto adjacent roadways and property. 

Crews in the community

In addition to using innovative technology for increased efficiency, OC Public Works has crews out in communities all year long to ensure they are clean, safe and ready for potential rain storms.  We lead a maintenance program that includes inspection  and cleaning performed continuously throughout the year to ensure those 320 miles of County roads and 380 miles of flood channels are working as designed.  Here's how. 

  • Our Operations & Maintenance crews remove debris, trash, silt buildup and make any repairs necessary to drain grates, catch basins, inlets, channels and roadways, to ensure storm water flows freely.  We maintain a channel cleaning and maintenance program that addresses vegetation trimming, debris, sediment, and trash in those flood  channels. This includes the Santa Ana River, all the way from the Orange County border to the Pacific Ocean.
  • The large equipment that allows OC Public Works crews to quickly clear areas of debris, mud or other materials include backhoes, excavators, large bulldozers, grading vehicles, haul trucks, trash compactors, street sweepers and vacuum trucks.
  • We constantly monitor National Weather Service weather forecasts and inspect all Orange County flood and road facilities prior to any upcoming rain events.  This is done throughout the county, yet of heightened focus currently is the Silverado Canyon area, where a 960-acre fire in September 2014 left steep mountain sides vulnerable to an increased chance of mud/debris flow in the event of heavy rainfall.

In the months of September and October, OC Public Works crews will continue cleaning all catch basins and drains, clearing road shoulders where needed to prevent buildup of debris, and installing preventative barriers where needed on public land, such as sandbags, hay bales, silt boards and k-rails, to redirect the flow of excess water, mud and debris during storm events.

Santa Ana River

Like all other OC Public Works flood channels and roads, inspection and  engineering staff conduct routine inspections of the Santa Ana River area to identify and remove any impediments that may block the free flow of storm water along the channel, particularly during rain storms.  The Santa Ana  River is routinely inspected at least once a month, yet we’re currently  working along the river on a weekly basis to clean the channel, conduct United States Army Corps of Engineers (USACE) levee inspections and address homeless encampments that become present in some locations along the river. 

OC Public Works designs these facilities and conducts these inspections and maintenance all year long with one main focus -- the safety of our communities.  When a heavy rain storm is forecasted, our crews step up these activities - often working into late hours of the night -- to be prepared and to respond to storm-related concerns.  And with the added use of technology, we're always looking for and implementing tools that can help us with faster preparation and response times.

Helpful Resources to Keep You Safe

Personal and Family Safety Preparation:  Make a Kit, Make a Plan and Stay Informed

  • Make a disaster kit that is portable in case you have to evacuate.
  • Have an evacuation plan.
  • Keep critical documents and medicine in one place for quick access.
  • Have a car ready to go with at least a half tank of gas.
  • Have a family communication and reunification plan.
  • Sign up for AlertOC at to receive notifications and announcements.
  • Sign up for OCFA Community Education tests at

 (Source: OC Fire Authority)

How to Prepare Your Home for El Niño

  • Have roofs repaired and leaks fixed by licensed and bonded contractors.
  • Clear gutters, downspouts and roof drains of leaves and other debris.
  • Report street storm drains to city public works departments or OC Public Works for those in the unincorporated areas.
  • Place sandbags to protect vulnerable areas against flooding around your home.
  • Trim all landscaping and branches away from homes, vehicles and power lines.
  • Have weakened trees inspected by arborists.
  • Prepare a disaster supply kit that is portable in case of evacuation.
  • Have a family emergency plan and reunification plan.
  • Keep critical documents, keepsakes and medicine in one place for easy access.
  • Keep sneakers, a blanket and water in your car in case of emergencies.
  • Photograph valuables at your home and property for future insurance claims if needed.
  • Sign up for AlertOC at