The scramble for sand is destroying the Mekong
bbc.com
bbc.com
This is all part of China taking over the whole region by providing power and thus building a silkroad all the way to Sihanoukville, where they ship goods south to Jakarta and west to Africa. Google what is happening there and you'll see it.
This is me driving a motorbike across what is now a totally dry riverbed in northern VN all because of unseasonably dry weather and hydrodam's upstream... https://imgur.com/a/7hfxRD7
But one thing I don't get is: once the dam is built and filled up, shouldn't the water be back to flow regularly? It seems the dam should only act as a buffer, but not cause a dramatic decrease in water flow. Is it because evaporation at the water basin is much higher than on the river?
[0] an episode of the show called "The Grand Tour" where they usually drive cars, but here they drove boats on the Mekong.
Then what happens is that the water is further away (lower) and people build houses closer... a big rain comes in and wipes away the houses. That is why in the wet season, you see stories in the news about all the landslides... which are a combination of building and deforestation for farming.
Epic levels of mismanagement and no education...
Lake Powell (which I've also been to) is HUUUUGEEE. The 'lakes' created from hydrodam's off the Mekong are tiny in comparison.
Yes, China is why Cambodia has a GDP increase of 7% each year and so many are leaving poverty. Death rates are going down. College Education is going up.
Amazing what a country can do if it comes in and actually helps others rather than the West with its puritans values.
Japan is still helping though. I guess not quite the West but they still are doing infrastructure.
> The scramble for sand is destroying the Mekong
Becomes
> Overpopulation is destroying the Mekong
You might add "one way is the scramble for sand" though there are plenty others.
Learning about various nations' successful, noncoercive programs to lower birthrate that are as far from China's policy, forced abortions, or eugenics as day from night, and that increased prosperity and happiness, leads you to embrace such programs. The book Countdown by Alan Weiss https://www.amazon.com/Countdown-Last-Best-Future-Earth/dp/0... describes several such programs, including in Thailand, Iran, Costa Rica, Mexico, and others.
The most effective solution to the Mekong situation, however partial, is contraception and family planning education.
Many problems would continue to exist and continue to get worse if local populations were to start decreasing over time.
That's really interesting, but makes sense. The sand in most deserts has been blowing around for millennia (or longer), and so would be extremely smoothed-off. Sand in the Mekong is relatively young, and not that far removed from when it was a rough chip off a rock upstream. The difference here is called sediment maturity [] IIRC from first-year geology.
But can anyone answer: why is mature, rounded, fine sand not suitable for binding concrete or for glassmaking? And how fine can the sand be -- wouldn't extremely fine grains classify as clays instead?
It's the jagged edges on 'fresh' sand that gives the mix strength. Smooth sand is fine for glassmaking (something I do along with metal and jewelry work) but horrible for construction, as it doesn't grip into the binding agent as well, and any serious load makes it turn straight into dust.
The sand can be as fine as possible, as long as it isn't rounded, and still be useful for construction work.
Sand is just a classification of grain size of soil. We make sand all the time at quarries by crushing rocks. Most of the aggregate used in construction is made this way or taken from a pit/dredged.
In fact, the more angular the aggregate is the less workable the concrete becomes. There is a sweet spot of angularity that is desired. I believe the main advantage to increased angularity is in durability (which is due to interlocking, I think, as well as increased void ratio leading to better air entrainment).
Also - the size of the grains is more important than angularity, so I also disagree with the statement that sand "as fine as possible" can be useful for construction work in the context of concrete. While tautologically true because anything too fine (passing #200) would be classified as a silt instead of a sand, the way that it's written is deceptive.
Disagree all you want but that doesn't change the fact I've done building construction, including laying foundation, and finer sand is far superior to coarser sand. In fact, coarser sand is rather horrible for construction.
Sand used in concrete needs to meet a gradation requirement. The gradation requirement uses all sizes of sand as aggregate.
And if we are comparing credentials (which I assume is what your building construction story and youtube link is for?), then I've done nothing but put holes in the ground and fill them up with concrete for almost a decade. Here's what I was doing in 2014: https://www.youtube.com/watch?v=E4Ixw69woSA
I'm talking about both sand in construction and in general (like for glassblowing, etc.) Portland cement uses the finest sands possible for holding concrete aggregate, which you only really tend to find in desert areas (if you're lucky enough to find a spot that hasn't been above water for more than a million years, that's one reason construction-grade stuff is so hard to find.)
Now days, I do very similar to your link, except it's through mountains, and terminates inside the mountain. Minerals extraction is fun!
I have seen this rumor repeated often and I think it is journalists trying to explain something they don't understand in a way that seems intuitive.
See "Compressive strength and hydration with age of cement pastes containing dune sand powder" Salim Guettala, Bouzidi Mezghiche, Algeria.
It just happens to be easier and cheaper to dredge where there aren’t any environmental laws.
Sand isn’t ‘renewable’ ..loss of river sand is just going to make things worse.
I don’t want to sound like a curmudgeon..but human extinction is imminent is we don’t protect our ecosphere and biosphere..this is assuming climate change can’t be stopped and so let’s not take that into account..lets assume that it won’t happen.
As a super apex predator, we need the underlying structure of our ecology and environment and all the habitats below us in the food chain..most importantly insects and frogs and birds...for us to survive here on this only planet we know.
The solution is just a severely whittled population with measures that will get us to a desired 2-3 billion in 150-200 years.
We have to maintain genetic diversity and dna code hygiene..it’s not genocide or eugenics if we don’t target a particular people or group for erasure. It’s for ALL of us.
This can be achieved by incentivizing those who subscribe to a non transferable quota of 1/2 surviving progeny. And preservation of their genetic material. Quality over quantity. The crush of human population will be our undoing.
For other species, population goes down by half is just another day. It wouldn’t even be classified as vulnerable if it were just going down by half. A large proportion of us will suffer or die, but that is not extinction, there’s no need to over dramatize things when the fact is serious enough.
I know it may be unpleasant to hear this... But some of us don't actually care. Seriously, somewhere we got "stuck" into thinking that we should (or can) perfectly preserve ecosystems whilst simultaneously advancing our civilization into amazing new levels.
However, if you look at it objectively we've already demolished and transformed huge swathes of the planet anyways without blinking; but now selectively decide to "preserve" some other things. Just look at all the land our cities take up, the roads that cut our landscape, the beaches that are peppered with housing, the rivers we've diverted, the dams we've constructed, the changes we've caused in the evolution of plants and animals, etc. Maybe even imagine how (perhaps horrible) our planet looks at night from outer space due to the lights we've erected all over it instead of letting it be naturally dark as it's been for eons.