Strong Storms Put California Levees to The Test

With multiple powerful storms continuing to bear down on California, state officials have warned that rural areas are the most at risk of flooding because the levees that protect them aren’t built to the same standards as others that shield more populated cities.

These rural levees – many of which are owned and maintained by private land owners – mostly protect farmland from flooding and pose minimal risk to most homes. But failures can cause major thoroughfares to flood, as happened on New Year’s Eve when a major highway in Sacramento County flooded and one person was killed.

California Desert Flooding Damaged L.A. to Phoenix Highway

The main highway from Los Angeles to Phoenix was damaged by a flash flood that washed out part of the road through the Southern California desert in the latest bout of punishing monsoonal thunderstorms that have hit the region this summer.

The newest round of flooding started Wednesday evening, damaging a roadway that was part of a detour past a repair project along eastbound Interstate 10 near the small community of Desert Center, about 165 miles east of Los Angeles.

Traffic in both directions was halted initially, but westbound lanes for motorists heading from Arizona to California reopened later.

California Trying to Reduce Flood Risk Along Rivers

Between vast almond orchards and dairy pastures in the heart of California’s farm country sits a property being redesigned to look like it did 150 years ago, before levees restricted the flow of rivers that weave across the landscape.

The 2,100 acres at the confluence of the Tuolumne and San Joaquin rivers in the state’s Central Valley are being reverted to a floodplain. That means when heavy rains cause the rivers to go over their banks, water will run onto the land, allowing traditional ecosystems to flourish and lowering flood risk downstream.

Government-Produced Flood Maps May Have Underestimated Properties at Risk

First Street Foundation, a nonprofit agency, is making accurate climate change-adjusted flood scores available for every property in the U.S. today. There are government-produced maps showing 8.7 million homes and properties at significant flood risk—and it turns out those may have underestimated the amount of real estate at risk by 67%. Or, in other words, an additional 6 million properties face a significant risk of flood.

Before these individual property scores were available, there was no easy way for your average homeowner or buyer to understand the flood risk associated with specific properties. That’s particularly problematic because climate change is causing flood risk to increase; there are more extreme rain events and coastal flooding than there used to be.

California Has Earthquakes, Wildfires, Floods and Volcanoes

(TNS) - Margaret Mangan didn’t sleep well in the weeks following the Ridgecrest, Calif., earthquakes. The July shaking triggered a swarm of smaller tremors in the nearby Coso Volcanic Field, a cluster of lava domes and cinder cones at the northern end of the Mojave Desert. And it was Mangan’s job to watch for a possible eruption.

“We were pretty much on 24-7 vigilance,” said Mangan, the longtime scientist-in-charge of the U.S. Geological Survey’s California Volcano Observatory.

Editorial: To Address the New Normal, Disaster Relief Needs to Start With Prevention

(TNS) - In Congress, battles are raging over disaster relief spending. Who should get the help? Puerto Rico, still seeking emergency reconstruction money in the wake of 2017 Hurricane Maria (and yes, Puerto Rico is part of the United States and just as deserving of help as, say, North Carolina)? How about Hawaii, where volcanic eruptions have seen molten lava destroy homes, roads and other infrastructure? Nebraska and Iowa, which were inundated by some of the worst flooding in their history? California, trying to rebuild from the most widespread and deadly wildfires the state has ever seen? Or the Florida Panhandle and parts of Georgia, where homes and farms were wiped out by the violent Hurricane Michael last year?

Oregon City Contemplates New Policy to Deal With Levees

(TNS) — The Warrenton, Ore., Commission plans to develop a new policy to address encroachments on the city's levee system.

A recent inspection of Warrenton's nearly 11 miles of levees revealed several issues. There are moles everywhere and, in several cases, there are structures built into levee slopes.

One example the U.S. Army Corps of Engineers has rated as "unacceptable" is a garage built into the levee right of way off Main Avenue near Fourth Street.

If the garage is not addressed, it could jeopardize the levee system's status within the federal Rehabilitation and Inspection Program, which provides rehabilitation assistance.

California Spillway to be Used Tuesday. The State Says it's Ready

(TNS) - Oroville Dam’s massive flood-control spillway will be deployed Tuesday for the first time since it was rebuilt for $1.1 billion after a near-catastrophe forced the evacuation of 188,000 people in 2017.

In a brief statement Sunday, the California Department of Water Resources’ deputy director Joel Ledesma said the agency has “restored full functionality to the Oroville main spillway and is operating the reservoir to ensure public safety of those downstream. The Oroville main spillway was designed and constructed using 21st century engineering practices and under the oversight and guidance from state and federal regulators and independent experts.”

Sea Level Rise Could Hurt California More than Wildfires, Earthquakes

(TNS) - In the most extensive study to date on sea level rise in California, researchers say damage by the end of the century could be far more devastating than the worst earthquakes and wildfires in state history.

A team of U.S. Geological Survey scientists concluded that even a modest amount of sea level rise — often dismissed as a creeping, slow-moving disaster — could overwhelm communities when a storm hits at the same time.

The study combines sea level rise and storms for the first time, as well as wave action, cliff erosion, beach loss and other coastal threats across California. These factors have been studied extensively but rarely together in the same model.

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