105,000 L.A. County residents live in areas prone to 100-year floods - Los Angeles Times
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Here are the parts of L.A. County most likely to be hit by catastrophic flood

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Nearly 105,000 Los Angeles County residents live within the designated 100-year flood plain, according to a report from the National Oceanic and Atmospheric Administration.

These people live in the 3.9% of county land that could flood in a 100-year storm — defined as a very large storm that has a 1% chance of happening each year.

A map of the flood plain shows which areas would be affected and includes the Venice Canals, coastal Long Beach, a large swath of Santa Clarita and an area just east of the Los Angeles River near Chinatown.

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A study published in the journal Nature Sustainability said the toll could be much higher, and found that Black, Latino and Asian residents were more likely to be affected than white residents.

Researchers say flooding from a 100-year storm could impact up to 1 million people in and around Los Angeles, 30 times more than previously estimated.

Oct. 31, 2022

As recent storms have battered California, entire communities have been displaced by flooding, from the seaside enclave of Montecito to the tiny Central Valley town of Planada.

Although L.A. County has been spared the worst of the pounding so far, with no reported deaths from the storm and damage less significant than that seen elsewhere, future storms could have a big impact. Seven schools and nine fire stations lie within the flood plain, as well as nearly 5,000 businesses, according to the NOAA report.

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To limit flooding risk, “development in flood-prone areas should be kept to a minimum,” and “creating more greenspace, which acts as a flooding buffer, lowers flood risk,” the report says.

Of the nearly 23 square miles of development in the county from 1996 to 2016, more than 10% happened within the flood plain.

As the county continues to develop land, the addition of more impervious surfaces such as concrete and asphalt “can increase runoff and exacerbate flooding,” even in areas outside of the flood plain, according to the report.

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The latest storm further swamps California, already reeling from widespread flooding, mudslides, washed-out roads and downed power lines.

Jan. 11, 2023

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