Brahmaputra

In the SE quarter of Ireland there are three rivers known as The Three Sisters which rise rather close to each other in the low hills of the Midlands and rush off in all directions before coming together again at the village of Cheekpoint and the Headland of Peace which has been transliterated from the Irish Ros an Sith as Russianside in Co Waterford.  The rivers are lovely in that understated way that helps normal people fall in love with the Irish landscape.  The Brahmaputra and the Ganges also rise really close together, the former in Tibet North of the Himalayas, the latter from the glaciers of the South face. The Ganges is the great artery of India, holy and powerful and at least 12 times longer than the Barrow the longest of our Three Sisters. The Brahmaputra flows a long way parallel to the Ganges until they come together in the World's biggest delta.  People in Ulster or Україна are likely to know bugger-all about the geography of South Central Asia, so I've imported a map:

We get floods on our rivers, particularly in the town Clonmel on the river Suir: another of the three sisters; the last being called the Nore.  It's a pain for town-centre businesses which are now no longer insurable against flood because it's a running certainty that it will be gumboots-all-round most Winters. But in Bangladesh, 6000 people die in floods every year.  I'm sure that will help the plain people of Clonmel reflect on how fortunate they are to live in a place with such unspectacular weather.

The problem in Bangladesh is a bit like the problem with our intestinal flora. In the past both have worked reasonably well; periodically things have gotten out of control but they have settled back down again after a flushing flood induced by unseasonable rains (Ganges) or unwashed hands (colon).  The one thing most of us can remember about Ancient Egypt and the Nile is that the seasonal floods brought a dose of Central African silt, mud and nutritious sludge which ensured the fertility of the flood-plain, dynasty after dynasty for 5000 years.  Since we had the hubris to intervene in the balanced regime of our guts by periodical medical onslaughts on the creatures living there, many of us are badly out of kilter with other aspects of our health: fat, wheezing, shedding skin and hair, and possibly getting cancer.  Similarly, there have been attempts to control the flow of water in the Ganges delta and that has tended to cause devastating floods at intervals rather than 'normal' floods that brought down a billion tons of sediment each year, most of that was washed out into the Bay of Bengal.  A billion tons is close enough to all the topsoil in a medium sized Irish county.  The sludge that didn't get washed out to sea extended and filled in the delta with nutritious material in which to grow wheat for chappattis and lentils for dal.

Normal floods can be controlled and harvested by normal methods - in the case of Bangladesh by lots of man-power and baskets.  In the case of Ireland as well until back-hoes and tractors appeared on the scene two generations ago.  The short handful of bachelors who used to live in our house would shrug on their crombie overcoats and trudge up the hill to trick about with the drains if they heard on the wireless that a storm was due.  A shovel and a few sods high enough up the mountain could save the lane from getting washed out. After the storm passed through the water could be allowed to flow down the hill again to provide drinking water for man and beast.  In Bangladesh they used to open the dykes that surrounded the polders at times when experience and legend suggested that they could capture some silt and then close up again when the tide turned.  When the dykes get out of human scale you can no longer capture the life-giving mud and when, under extreme weather conditions, the super-dyke is breached you are likely to lose your fields, your home, your family and your life.

There are two related problems for Bangladesh: one is that the land is sinking at between 5 and 25 mm a year partly from the effect of tectonic shift and partly because of compaction of the soil as water and air get forced from it by traffic and the broiling sun. The other is that, under the rules of global warming the mean sea level is rising, so that the relative difference in the height of land and tide is getting less each year.  The article in Nature has a great map with notes on the different sorts of evidence that show the land is sinking. The consequence is that pretty much every region of the entire delta has experienced at least one catastrophic since 2000 and nobody is suggesting that these floods aren't going to return. Of all the countries that are threatened by rising sea-levels, Bangladesh is perhaps the most populous country at risk, with a large proportion of her 150 million people living no more than a broom-stick above the high-water mark.  The Dutch, The Experts in water-meets-land matters, have formed a joint venture with the Bangladeshi government to come up with some workable solutions to this issue.  You have to do scientific research before you start any works because otherwise you are as likely to make the situation worse as make it better

But let's end on a more positive note.  The Brahmaputra, like the Severn and the Petitcodiac, is one of the few rivers in the world that experiences a tidal bore - and the water is so warm you'd hardly need a wet-suit if you wanted to surf upstream.