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WHEN THE RIVERS RUN DRY

Fred Pearce is an environment and development consultant whose latest book is When the Rivers Run Dry : Water--The Defining Crisis of the Twenty-First Centuryw.

 rqOur list of things to worry about – global warming, oil shortages, bird flu, terrorism, etc. – seems to grow every year. Why do you say water is the “defining crisis of the twenty-first century?” 

Oh, there are plenty of things to worry about.  Most of them arise from Homo sapiens having to work out how to live together in ever greater numbers on the one planet.  Right now we seem to be good at finding technical and organizational fixes (none of the above are really insuperable problems), but rather poor at finding ways of making them happen.  In truth, I’d put water up there with global warming at top of the agenda.  Many climate scientists think that our big problems with global warming will come less from the warming itself and more from the big changes in hydrology that it causes – droughts and floods, dried out soils and ecosystems, empty rivers, and maybe the worst, the sheer unpredictability of where and when we will have water. 

But water also defines quite well our problems in moving from a world of apparently plentiful resources – a world in which if we screw up we can move on – to a world of finite resources, where we have to manage carefully to get by.  We still often see water as an essentially free and unlimited resource.  But it isn’t.  The public policy response to water shortages is still to build a new dam or sink a new well, with little regard for the thought that there may be no more water in the river to be captured, or underground to be pumped. 

Apart from the air we breathe, water is the most basic, most urgent, need that we all have.  We can survive for a while without food, but not without water.  We can survive forever without oil – but not without water.  Water has no substitute.  The good news, though, is that it is a constantly renewed resource.  The natural water cycle of evaporation and rainfall constantly cleans and recycles it. We will never “run out” of water in the way we might run out of oil.  So the trick, as we find local and sometimes regional reserves running out, is to realise that fact, and to manage our use of water in a way that meshes with the natural cycle. 

From that perspective, managing water is a model (and, because of its urgency and universality, the defining model) of how we deal with nature.  Not as a force to be confronted, but as a force to be nurtured and to be worked with.  That notion holds in every sphere from using “soft engineering” in order to manage floods, to harvesting the rains and to preserving wetlands. 

The short answer to the question, therefore, is that meeting water needs (and managing our water demand to fit water availability) is both a major challenge in itself for the 21st century and will define more widely our ability to coexist with nature and make good use of the planet’s fast diminishing “natural capital.”  And my belief is that if we can get water right we will be able to get most things right.

Explain to us the value of wetlands, not just for their biological diversity, but for their effect on our water resources. 

There are of course many sorts of wetlands: from lakes and ponds through marshes to bogs, flooded forests and floodplains.  But all hold water.  In general, on river systems, they act as holding tanks for water.  They may also help maintain underground water reserves, and hold back water from reaching rivers after heavy rains.  They even out rivers flows.  When a river is in flood, it will naturally tend to deposit water in wetlands all the way down its course.  And heavy rains may be delayed from reaching the rivers themselves by the intervention of wetlands. 

These days most of the world’s wetlands have been drained, and floodplains barricaded off from rivers, so they can no longer perform this function.  That means when the rains come, the water is rushed much faster into the rivers, and then downstream, dramatically raising flood risks.  However much engineering we do to try and rush that water to the sea, we are likely at greater risk of flooding – as centuries of intervention on the Mississippi shows. 

And just as the destruction of wetlands causes bigger floods, it also causes bigger droughts. If the wetlands are drained, there is less water on the land when the rains fail.  The river flows are lower than they would otherwise be.  We spend billions of dollars building dams to catch water that nature once caught for us at no cost.  Now, of course it is not always possible to recreate all the wetlands and remake natural rivers.  But we need to realise the free benefits that were once available to us from wetlands; plug those into cost-benefit calculations before we remove any more; and assess whether sometimes there would be real benefit in recreating the lost wetlands.  These things are currently usually done for aesthetic or recreational benefits.  Those benefits are real enough.  But the benefits from wetlands are in reality much wider.  They are hydrological as well as ecological. And so the case for much greater protection and re-creation of wetlands is much greater than commonly supposed. 

Dams are a clean source of electric power, a way to control flooding and can provide a water source during droughts. What is the downside to building dams? 

For the reasons you state, environmentalists in the old days loved dams.  But no more.  The reservoir itself is a problem – flooding large areas of land that may be scenic, home to many people and often, being in a silt-covered river valley, good farmland.  That is a major loss.  Worldwide tens of millions of people have lost their homes, land and livelihoods to large dams. 

Dams are built to “manage” river flows, so ensuring there is water to power turbines when it is needed.  So, downstream, the flood “regime” – the seasonal rise and fall of water levels and flow speeds -- is dramatically altered.  This disrupts natural systems, like fish spawning areas and wetlands, and many human activities, like planting crops on river banks and floodplains after the annual flood.  In general, fisheries created in reservoirs behind dams do not compensate for the lost fisheries on the river itself. 

It is not just water flow that is disrupted by dams.  Most reservoirs accumulate silt from the rivers they barricade.  As a result, downstream river flows are less silty.  This again disrupts fisheries and wetlands, and farmers that irrigate with river water no longer get the benefit of the nutrients in the silt.  Also a silt-free river tends to erode river banks.  And, if it fails to regain the silt it once had, it may even have effects on coastlines.  In some parts of the world, shorelines are only maintained by the constant supply of new stabilizing sediment that comes from rivers – and when (for instance at the Akosombo dam in Ghana) that source of sediment is lost, rapid coastal erosion occurs. 

Dams are often advertised as both generating electricity and protecting against floods.  But there is a problem here.  To maximize electricity generation, reservoirs need to be kept as full as possible.  But to protect against floods, they need to be kept as empty as possible.  In practice, most are kept full – so when the big rains come, dams tend to create floods rather than preventing them.  Often dam operators are forced to release large volumes of water very fast to protect their structures – with sometimes catastrophic results.  The book has a chapter full of examples. 

Dams provide power over rivers.  The question, often, is who has control of the sluice gates.  Usually the cities get the electricity and the rural inhabitants of the river valley bear the damage.

You call the Yellow River in China, the “hanging river.” What does that mean and what is the potential for disaster? 

For thousands of years, the Chinese have controlled the Yellow River as it crosses its floodplain on its last several hundred miles' journey to the sea, by constraining it within artificial banks, levees.  The idea is to prevent floods. y But the river is the world’s siltiest and through time it deposits this silt on its channel bed, which rises higher and higher above the surrounding floodplain.  The Chinese have kept the river on its course by raising the levees ever higher.  Hence the term “hanging river”.  But this is a “double-or-quits” strategy. Chinese history is peppered with disasters when the river breaks its levees and floods across the land.

But the worst disaster happened deliberately, in 1938, during the Sino-Japanese war. To halt advancing Japanese troops Chinese generals dynamited the levees and flooded the land.  The Japanese were only held up for a few weeks, but the floods were so great that almost a million Chinese died.  It is said to have been the most destructive single act of war ever.  And it took engineers ten years to put the river back into its old channel. 

Today the risks are if anything higher.  A combination of persistent drought and rising demand for water for irrigation leaves the river virtually empty by the time it reaches the “hanging river” zone.  That sounds comforting.  But the slow, feeble river drops even more of its silt on its channel than before.  So the hanging river has been rising ever higher (it is now in places 70 feet above the floodplain) and, despite constant levee raising, the capacity of the channel is diminished.  The risk is that one year there will be major upstream floods that dams cannot contain, and the levees on the floodplain will once again be overwhelmed, with dreadful consequences.  Chinese engineers have been trying to manage dams on the river so as to create an artificial flood to flush out some of the silt and increase the capacity of the channel.  But this has had only limited success, however.  

How would you recommend the United States approach the problem of rebuilding New Orleans after the devastation of hurricane Katrina? Or should we rebuild New Orleans? 

New Orleans, lying below sea level on the delta of the Mississippi, is at constant risk of flooding from both the sea and the river.   Its history has been a constant battle of raising levees higher.  It is clear that when Katrina struck they were too low.  The storm surge burst into the delta and overwhelmed the defences.  But the situation had been made much worse, and the city was super-vulnerable, because the natural wetlands both on the delta and upstream on the river have mostly been “reclaimed” and drained.  So when floods come, either from the sea or the river itself, there is nowhere for the water to go.  That means water levels round New Orleans are much higher than they would otherwise be. 

Arguably, New Orleans is a crazy place to have a city.  But if New Orleans is rebuilt – or indeed continues to be occupied at all -- there is an urgent need to recreate these natural flood reservoirs, so that next time the water has somewhere to go other than seeking out the weakest point in the levee system.  Louisiana must tear down levees around farmland in order to protect the city.  

You mention that water wars are not something off in the future, but have been occurring in the Middle East for some time now. Would you tell us a little about that? 

Water conflicts of various sorts are happening all over the arid parts of the world.  As more and more water is collected behind dams, and otherwise controlled, it is the powerful who get access to the water and the weak who lose.  So there is a serious global issue about water governance.  The first modern water war was, arguable at least, the Six Day War in 1967 between Israel and its neighbours.  Ostensibly about land and security, Israel’s Ariel Sharon (who was a general at the time) has said in memoirs that it was really about water – specifically the River Jordan, which then as now was Israel’s biggest source of water.  The country feared that Syria was about to annexe the headwaters of the river for its own uses.  At any rate, when the war ended, Israel was in charge of the river for most of its course, including the headwaters on the Golan Heights and has retained them tenaciously ever since, virtually emptying the river before it flows into the country that bears its name. 

Since 1967, Israel has also ruled on the West Bank, where rainwater percolating into an underground aquifer provide it with another source of water.  And it has prevented Palestinians living there from sinking new wells or expanding their water sources, with sometimes serious consequences in a fast-growing population.  Israel argues (correctly) that the aquifer is fully exploited, but now takes the majority of the water there for its own use.  Israelis are divided about whether they can afford to give up part of their “share” of the West Bank water in a peace deal.  But any peace settlement will require an agreement on water, as well as land.  

What countries do you put at the top of your list for adequate, clean water supplies and an understanding of the proper way to handle such a valuable resource? Which countries are at the bottom and can be expected to suffer a water crisis in the near future? 

Oh boy, the bottom countries are easy.  The two biggest per capita water users on the planet are two near-desert states: Uzbekistan and Turkmenistan.  These two former Soviet republics in central Asia are the countries responsible for emptying the Aral Sea, once the world's fourth largest inland sea but now a wasteland of endless and largely unexplored desert, by decanting the waters of the Amu Darya river onto their cotton fields.  Their water crisis is major -- and now.  Especially in the Uzbek province of Karakalpakstan.  They get to drink and irrigate their crops with drainage water from the cotton fields.  It is salty and unpleasant. Their entire environment is arid (temperatures have soared since the sea dried up) and full of salt, from both the water and the salt-laden dust storms that blow from the dried up sea bed.  The salt is causing epidemics of cancers and anaemia.  Life expectancy here has fallen by 10 years.  It is ecocide. 

Countries that do things well?  Pat on the back for the US for introducing low-flush toilets.  As a result you now consume less water per head than Canada (and many times less than Turkmenistan).  Pick of the bunch is probably the city state of Singapore which has got leakage rates from city water mains down below 5 per cent (25-50 per cent is more typical in most cities worldwide.) Europe probably has the cleanest water, and while southern Europe is emptying rivers and aquifers to irrigate crops, the rest of the continent, where water demand is much less, has succeeded in keeping water crises out of the headlines. 

The world has elected you, Fred Pearce, Earth’s Emperor of Water. Your first duty is to lay down five laws concerning our access and use of water. All the nations of the world have agreed to abide by your edicts. What are they? 

Phew, hard question. 

  1. Access to clean water is a human right, and should be so enshrined in international law.  The world should have a programme – paid for by the rich nations, if necessary – to make that right a reality.

  2. Most of the world’s major rivers cross international boundaries, and yet are not covered by treaties.  This is a recipe for conflict and for upstream users to hold downstream users to ransom.  There need to be internationally brokered deals sharing such rivers.

  3. Underground aquifers, being out of sight, are often out of mind.  But these are vital resources that need protecting from rampant overpumping.  There may be exceptions, but there should be a universal presumption that aquifers should not be pumped so much that water tables are lowered.

  4. Large dams and other river engineering projects are often carried out without regard to the wishes of people who will be damaged by them.  This was condemned in the reports of the World Bank initiated World Commission on Dams, and its strictures on consultation and full environmental and social impacts assessments should be enshrined in law.  This regime should be extended to give communities proper control over the water on their territory.

  5. In a market-dominated world, we need to work towards more realistic water pricing.  Only that way will water conservation become the priority that it needs to be, whether in the home or the factory or at the irrigation project or hydroelectric plant.



March 14, 2006


Paul Comstock