LA County Public Works / Flood Control District

Update and improve emergency preparedness.

Although flood infrastructure is in place to protect life and property, flooding can still pose a threat to communities within the floodplain during an extreme storm event. These communities, which are protected from routine floods, must still be prepared. The…

Include climate change research in the planning process for new projects along the river.

Current infrastructure in and along the LA River was designed based on historic climate data. However, a changing climate is likely to increase the frequency of extreme precipitation events that result in flows that may exceed the channel’s current capacity.…

Reduce peak flood flows into the river.

In addition to increasing capacity of the river, flood risk can also be improved by reducing the amount of water that enters the LA River at peak flows. Upstream storage or detention facilities, such as dams, help to store runoff during…

Increase capacity of the river in high risk areas to provide flood risk reduction to at least the 1% (100-year) annual chance flood event or to a level recommended by a risk assessment.

Levels of flood risk management vary along the 51-mile channel. The 1% (100-year) event is used as a target in this plan because it is the standard for the National Flood Insurance Program (NFIP) and studies show that using this…

Maintain existing flood carrying capacity of all reaches of the LA River channel.

Because existing development gets close to the channel, it is critical to maintain the existing flood carrying capacity of all reaches of the river to manage flood risk for people and property during storm events.