. . . until there's not a drop to drink. Rivers, such as the Rio Grande and Colorado in the US, the Aral Sea in Russia and the deep aquifers in India are disappearing. Human use, particularly for large-scale agriculture, is drawing more water than Nature can replenish. Water is being channeled, impeded or diverted, and contained. The result is the natural flow of water being severely altered in places around the world. In this captivating and rather disturbing account, Fred Pearce describes how the flow has been altered by us and what the results of our tampering portends.
Pearce is not afaid of numbers. Think for a moment of what a "cubic kilometre" of water suggests. What lies about a kilometre from your house? Project that distance sideways and upward and envision the area filled with water. Multiply that by 10, by 100, then consider those amounts flowing by every minute, every day, every year. The image can only be called "imposing". These are the values the author deals with in describing rivers, underground aquifers, diversion canals and hydroelectric dams. Too often, the number that was and the one that is today are drastically different.
Once, irrigation was the diversion of a small portion of a river's content. Now, entire rivers pour into fields for crops. Much of that water seeps away unused or evaporates. When there are many farmers "abstracting" water, legally or illegally, Pearce notes, the result is deprivation elsewhere. Treaties written to share water resources may be rendered invalid by such abstractions, since natural replenishment cannot keep pace. The Nile has been a source of contention for millennia. Even the British Isles, usually considered eternally green and damp, is suffering droughts. Recently, a deal between the US and Mexico has left the latter nation in a "water debt". Mexico must shift water from it's own farmer's fields to pay it off. The debt, of course, is due to water abstracted far up the Rio Grande to fill swimming pools and keep golf courses green.
Great dams, once heralded to protect water resources, are now known to cause immense problems. Some evaporate water faster than the inflow can replenish it. Other times heavy storms threaten the dam's structural integrity requiring the operators to release massive discharges flooding downstream farms and communities. Silting, always constant in rivers, lead to reduced capacity. The real threat today, says Pearce, is that the sources for the water the dams are supposed to contain are shrivelling - the mountain glaciers that feed the streams filling the dams. The adding of more dams over the 45 000 already existing will not provide more water. For one thing, all the best sites are taken.
These changes in water availability are happening rapidly and are becoming serious international issues. North of the contested Nile, Israel's water policy is draining the resource away from Palestinian communities. Israel's control over the area's water is nearly absolute, leaving the Palestinians to buy tanker water. On the subcontinent, not only is India struggling with its neighbours over water, internal squabbling among States and communities is rife. Farmers, having lost water to dams and other diversions, are drilling boreholes to tap underground aquifers. They told Pearce they're aware the water tables are dropping because wells dry up and new bores must be drilled. "We have to get the water as long as we can" - and every farmer is in contention with his neighbours for the resource.
Water, of course, recycles. Except where it's weighed down by pollutants, water will rise to become rain. The rains are erratic and local reliability is declining. Pearce offers some suggestions about trapping water. Fog, it seems, offers a ready resource in certain areas and it suitable for pasturage or gardens. Trapping the rains with checkdams to limit runoff is a growing method, particularly in hilly areas. For agriculture, the "drip feed" offers the most promise for crops.
Pearce's masterful and comprehensive account is long overdue. While many studies have focussed on climate change and unconstrained pollution of the atmosphere, he demonstrates the effect of these conditions on the ground. If the water isn't there to nourish the crops, we don't eat - it's as simple as that. Relying heavily on personal observation and interviews to produce this book, the author presents it as an account all can understand. That's an admirable aim. He provides maps, but doesn't overload the reader with charts and graphs. The only lack in this book is references to the source of his staggering numbers. Few, if any, will doubt their veracity, however. It is, after all, the history and future trends that remain the foundation of this book. [stephen a. haines - Ottawa, Canada]