Tag Archives: flooding

salt intrusion in New Orleans

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As a water professional, I of course have access to cutting edge sources of news in my sector not available to the general public. I first heard about the saltwater intrusion situation in New Orleans from a random drunk guy in a bar the other day.

Because of the drought across the Mississippi River Valley, salt water is creeping upriver, where many communities, including New Orleans, draw their drinking water.

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So not enough water coming from upstream to keep the saltwater from the ocean at bay. I wonder how much effect sea level rise has on this right now. In the future, it certainly will, and climate change may cause more and frequent droughts, although I don’t know what the forecast is for the U.S. Gulf region specifically.

This appears to be a short-term phenomenon. The salt will come and go. Cities will figure out how to get safe drinking water to people, they will keep the taps on so people can take showers and wash their clothes and fire fighters can fight fires, and they will assess any damage from corrosion after it passes. If it happens more frequently though, it seems like we need more of a plan than this. And groundwater salt intrusion is a longer-term, slower-onset issue but once it is there it is going to stay there in many cases.

So both flooding and drought are going to impact our coastal cities, like a one-two punch, over and over again. We might be able to deal with it for awhile, but if the recovery is not quite complete each time there is an episode, the impacts will accumulate over time until finally, there is some big event that is the one a city can’t recover from.

September 2023 in Review

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Most frightening and/or depressing story: “the accumulation of physical and knowledge capital to substitute natural resources cannot guarantee green growth“. Green growth, in my own words, is the state where technological innovation allows increased human activity without a corresponding increase in environmental impact. In other words, this article concludes that technological innovation may not be able to save us. This would be bad, because this is a happy story where our civilization has a “soft landing” rather than a major course correction or a major disaster. There are some signs that human population growth may turn the corner (i.e., go from slowing down to actually decreasing in absolute numbers) relatively soon. Based on this, I speculated that “by focusing on per-capital wealth and income as a metric, rather than total national wealth and income, we can try to come up with ways to improve the quality of human lives rather than just increasing total money spent, activity, and environmental impact ceaselessly. What would this mean for “markets”? I’m not sure, but if we can accelerate productivity growth, and spread the gains fairly among the shrinking pool of humans, I don’t see why it has to be so bad.”

Most hopeful story: Autonomous vehicles kill and maim far, far fewer human beings than vehicles driven by humans. I consider this a happy story no matter how matter how much the media hypes each accident autonomous vehicles are involved in while ignoring the tens of thousands of Americans and millions of human beings snuffed out each year by human drivers. I think at some point, insurance companies will start to agree with me an hike premiums on human drivers through the roof. Autonomous parking also has a huge potential to free up space in our urban areas.

Most interesting story, that was not particularly frightening or hopeful, or perhaps was a mixture of both: Venice has completed a major storm surge barrier project.

Venice flood protection

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The Italian government has completed an $8 billion coastal flood protection system. It is interesting because it is submerged under normal sea conditions and can be raised when a storm is coming in.

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$8 billion sounds like a lot of money, but perhaps it is not to protect a major coastal city and international cultural treasure. The U.S. Army Corps of Engineers has spent $14 billion to protect New Orleans and is undertaking a projected $31 billion project to protect Houston (and projections have a way of running over). These are guaranteed to be far uglier projects than the Venice one. These U.S. cities may have “benefitted” from being the first to be devastated by coastal storms in the climate collapse era. Do we really think the U.S. Congress will not pony up even more enormous sums to protect New York, Washington D.C., and San Francisco when the time comes? They will. Cities with major military bases like Norfolk, Virginia and San Diego might make the cut. Smaller but still major cities with less political clout may have more trouble getting their fair share. Boston and Miami might make the cut. Major cities with less political clout, like Philadelphia and Baltimore, might not make the cut. And all this money Congress will find to protect major urban areas, while it will have some economic multiplier effect, will be money not spent on other priorities.

Houston Flood Protection

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The U.S. Army Corps of Engineers is undertaking a $31 billion, two decade project to build a system of flood protection levees and gates for Houston. At first I thought maybe it was designed during the Eisenhower administration and the Corps is just now getting around to building it. But no, it’s nickname comes from Hurricane Ike in 2008. According to Grist, this is “the largest project that the Corps has ever undertaken”. This is impressive, considering the size, scale, and speed (by Corps standards) of the levee construction to protect New Orleans after Hurricane Katrina. Both systems are being questioned as possibly under-designed for projected future climate conditions. It does tell me one thing though – the U.S. Congress will pony up to protect major coastal cities when push comes to shove. There will be more to come.

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yes, the Dutch are good at water…

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It’s actually true that the Dutch are good water engineers. It’s just slightly annoying that the Dutch themselves are fond of telling us that, and then like to remind us frequently of that fact. Nonetheless, here’s a roundup of Dutch water engineering stuff. A lot of it is just using data analysis and computer simulations to predict what is going to happen and then designing clever interventions to nudge it one way or another. That is good basic engineering using modern tools, and not always done in other countries where political priorities lie elsewhere. Some of it is just a willingness and ability to pay for the aesthetic side of design, even if it costs a lot and takes a long time. The Dutch are patient, science- and logic-driven, and rational. I suppose they have earned the right to be just a tiny bit smug about it.

coastal inundation value at risk

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Union of Concerned Scientists has tried to combine inundation mapping, property value estimates from Zillow, and property tax information to give an idea of property value and tax revenue at risk from rising sea levels. They chose a time horizon of around a 30-year mortgage. It seems a bit coarse to me, but it still illustrates that with available information, insurance companies, mortgage lenders, and real estate markets are going to start piecing this together and it is going to start showing up in buying decisions and prices.