Flood Preparedness


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Flood

The risk of catastrophic floods exists every year, and heavy downpours often lead to dangerous flooding conditions. Because flooding can occur anywhere, it is important for residents to assess their flood risk, prepare and practice response plans, and learn from past floods. When flooding occurs, affected areas may sustain damage to structures and personal property, as well as severe damage to the environment in the form of soil erosion and deforestation and damage to utilities and transportation systems.

Hazards

Huntington Beach sits in a flood plain and historical flooding which dates back to 1825. Weather conditions are consistent with coastal southern California, with the greatest threat of severe winter storms during December through March. The threat from tropical storms is greatest in August through October, as a result of hurricanes from Mexico during that timeframe. The southwest facing beach of Huntington Beach can experience surf and wave impacts from both winter and summer storms. Heavy rains combined with high tide and large surf creates an increased potential for flooding. High tides may prevent flow from the Santa Ana River into the Pacific Ocean resulting in flooding in the south end of Huntington Beach.

In Huntington Beach, 75% of the city sits 25 feet or below sea level which increases the vulnerability to flooding.  The city has a vast network of flood control facilities to prevent flooding, but heavy rains have the potential to exceed the capacity of the system and cause flooding throughout the city. During periods of heavy rains, water fills the storm drainage system to capacity. Nearby pump stations are unable to pump the accumulated rainwater into the substandard flood control channels, which causes drainage problems. In addition, a large portion of the southeastern area of the City of Huntington Beach has a high water table. When the City experiences heavy rains, the land becomes incapable of absorbing any additional water and flooding may occur. Some of the high water table areas have been classified as wetlands. Finally, High surf occurs when wind from storms at sea forces the water level and wave action toward the shore. Typical surf in Huntington Beach is two to four feet, but waves up to 25 feet have occurred during heavy storms.

The flood hazards that potentially threaten Huntington Beach include:

  • Santa Ana River: Inland runoff from San Bernardino, Riverside, and Orange Counties fill the Santa Ana River. The river is the eastern border of Huntington Beach. The mouth of the river flows into the Pacific Ocean through Huntington Beach.
  • Coastal Storms: Being a coastal community increases the threat of storms with high winds and flooding. High surf occurs when wind from storms at sea forces the water level and wave action toward the shore. Typical surf in Huntington Beach is two to four feet, but waves up to 25 feet have occurred during heavy storms.
  • High tides: During high tides, it may become more difficult or even impossible for the Santa Ana River to empty into the ocean and therefore cause floodwaters to back up into residential areas. High tides generally affect the areas of Sunset Beach and Huntington Harbour.
  • Tsunami: Although tsunamis are rare, they remain a potential threat to Huntington Beach as well as every coastal area.
  • Dam Failure:The Seven Oaks Dam and Prado Dam are flood control dams that control flood flow along the Santa Ana River. Approximately 47 billion gallons (145,600 acre-feet) of water can be stored in the Seven Oaks reservoir and 61 billion gallons (187,600 acre-feet) in the Prado reservoir.

How The City Prepares

The City has a Flood Response Plan that is an Annex to the City Emergency Operations Plan.  Before a storm, staff gather information an begin planning for potential impacts.  The city has key thresholds that designate how the city is going to respond.  If certain threshold is met, staff will activate the Emergency Operations Center (EOC).  The EOC is a designated facility where trained staff can to coordinate the City response.  

During a flood response The mission of the City  is to preserve life, property, and the environment. To accomplish this, staff has several objectives. These flood-related incident objectives will normally take precedence over the routine day-to-day mission objectives of the involved agencies:

  • Aggressively warn the public of flood threats and provide timely and actionable information. 
  • Coordinate and assist the mobilization and employment of city resources to respond to flooding.
  • Conduct evacuation operations from threatened areas and provide care and shelter as needed.
  • Conduct rescue operations for individuals trapped by flood or in the water.
  • Restrict non-resident access to the area to prevent threats to life safety.
  • Provide appropriate security to evacuated areas.

How You Can Prepare

  • Know your risk and get flood insurance.  For more information visit the Community Development Department flood page.
  • Store key documents, such as copies of birth certificates, passports, medical records, and insurance papers in a safe, dry place. Keep original documents in a watertight safety deposit box.
  • Stay informed by following the cities official social media accounts, sign up for AlertOC
  • Have a grab and go bag for each member of your family and pets in case you have to evacuate at a moment's notice. 
  • Have a plan…know several ways to evacuate your neighborhood, have a plan to communicate and reunify with your family.