El Niño Dramatically Reshaped Western Coastlines

By Nathaniel Scharping | February 14, 2017 4:16 pm
SantaCruz_Hegermiller_2016

Large storm waves crashing on the rocks near Santa Cruz, California. (Credit: Christine Hegermiller, U.S. Geological Survey)

Beaches and shorelines are locked in an eternal battle between land and sea.

The struggle usually comes out to a draw — the rate of erosion is offset by the amount of new sediment deposited. But as weather patterns grow more erratic and storms intensify, our shores could begin yielding ground to the waves.

The most recent El Niño event was one of the most energetic in years and brought powerful storms and punishing waves to the Pacific Northwest. While this may have been good news for a drought-stricken region, it also pounded beaches that protect coastal communities from erosion and flooding. A new study, led by researchers from the United States Geological Survey, assessed the work of the 2015-2016 El Niño and found erosion was 76 percent higher than normal levels. 

Ocean Getting Greedy

The researchers surveyed 29 beaches in California, Oregon and Washington measuring sand and sea levels, topography, and wave energy. They compared their findings to data reaching back to 1993, and say that the sediment reserves have never been this far depleted. In a paper published Tuesday in Nature Communications, they implicate a variety of factors: stronger waves, changing storm patterns and a persistent drought failed to replenish sediments along the coast.

While El Niño events of comparable strength have occurred, the unprecedented levels of coastline erosion could be due to changes in age-old storm patterns. The researchers say that storms have been steadily making landfall further and further north, altering the patterns of erosion. At blame are shifting weather patterns attributed to global warming, particularly the sub-tropical jet stream.

Coastal erosion is all too real for one Alaskan village, whose residents this summer voted to relocate their entire town further inland to avoid being consumed by the sea. The ice that once shielded their low-lying island had gradually succumbed to warming seas.

Communities At Risk

A similar process could take place in the Pacific Northwest, where sandy beaches take the place of protective ice. Sediments are usually replenished during the summer by runoff from rivers, but the recent drought dried up those waterways and starved the shores of their yearly payload.

To delay shoreline losses, communities at risk could rely on artificial beaches of trucked-in sand, as Florida has done. These measures are costly and fail to address the underlying issue, however. If the normal give and take between rivers bringing sediment and the ocean washing it away is not restored, the beaches will only continue to wither.

Rivers in California are currently bursting at the seams, which offers some hope for beleaguered coastlines. A swollen Oroville River, near Sacramento, forced engineers to open Oroville Dam spillway for the first time, prompting the evacuation of nearly 200,000 residents. More rain is likely on its way.

The sudden glut of rain is a welcome sight in California, which has been suffering through a years-long drought. This reprieve may be brief, however. Just as changing climatic conditions are pushing storms northward, so too are they affecting rainfall, and a recent study suggests that the California drought has only been intensified by a warming world.

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  • http://www.mazepath.com/uncleal/qz4.htm Uncle Al

    The most recent El Niño (torrential rain, etc.) was both the strongest such thermal event ever recorded and California’s deepest historic drought. Following was a weak and transient La Niña (drought) that deluged California, demonstrating that state’s vaunted water management infrastructure was built shoddily and corruptly. Now, we have return of El Niño, maybe, and who knows WTF about anything.

    the California drought has only been intensified by a warming world.” Are pigs ariborn? Glaciers, gender, and science authored by U/Oregon professor Mark Carey: Scientists must further “feminist political ecology and feminist postcolonial” approaches re glaciers and climate change. The study was part of a ~$500,000 federal grant.

  • https://www.facebook.com/pages/My-Original-Music-written-arranged-produced-by-ME/195887277117017 JohnnyMorales

    This blog post plays extremely loose with the facts.

    Drought or no Drought very little of the water of all the California rivers reaches the oceans these days.

    It’s been decades since any of them from the SF Bay on South have carried anything more than a fraction of their historic sediment load, because most of their flow is transported inland and utilized by agriculture, industry and people.

    Agriculture gets about 80% of the diverted water to grow crops and raise livestock in arid Central Valley and the desert South of the state.

    The SF Bay used to be a mostly freshwater/brackish estuary, but these days ocean water penetrates far inland past Richmond to Vallejo. This dramatic change ensures the sediment never reaches the ocean. Instead it settles out far inland for decades until massive flood conditions provides enough water to flush some of it out.

    On a routine, average year, what does reach the ocean consists of mostly second level treated waste water from urban and industrial areas after they have used their approx. 20% of CA water supply for whatever.

    To imply that wastewater (often piped a mile or two offshore) and the tiny balance left in CA rivers to maintain habitat somehow are still able to provide enough sediment to maintain CA beaches in normal years is absurd.

    North of there small rivers that in other states would be called creeks still carry sediments to the ocean, but as the often clogged Delta of the Russian River demonstrates in total it’s hardly a significant amount, and definitely not a big player in keeping the ocean at bay by maintaining the beach fronts.

    On what basis does he claim the battle between land and see at the shoreline is usually a draw?

    A real estate agent selling beachfront property could be expected to say something like that to potential customers, but no one writing a science blog should.

    It’s an absurd statement. It’s usually either/or.

    The land area is increasing or eroding faster than it can be restored by erosion. Coastal areas are particularly known for constant change.

    If his statement were correct, then desert regions of the world must be experiencing the heaviest beach erosion, because they have very few rivers to erode the land and carry it to the ocean to maintain the beaches, but they are not any more affected by this than other coastal areas with different climates.

    About the only places where it “seems” to be draw is where humans have intervened heavily to preserve the coastline as it was when whatever coastal location became built up.

    As for the Alaska Island he mentioned, it’s a Barrier island. Barrier islands are constantly moving. Being in the high arctic doesn’t seem to change that. Nothing makes that more clear than the furthest North bit of land which is part of Greenland.

    It too is a barrier island. It moves so much it’s been lost for years at a time, only to be relocated somewhere else in the general area in time to maintain its claim to being the furthest North land on the planet.

    All in all, I’m sure there are plenty of examples of anthropomorphic global warming affecting coastal regions adversely, this isn’t one of them.

    In fact this article plays so fast and loose with the facts, it probably serves the purposes of the deniers better, because it provides plenty of holes for them to point out in order to cast doubt on the science in general.

  • SantaCruzMommy

    This is not El Nino. We are calling it ‘Lucifer’s Storm’. Get your science facts straight.

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