Lecture 11 - Case study no. 2: International river basins I...

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1 Case study no. 2: International river basins I mentioned yesterday that over 100 percent of the water in the Amu Darya is withdrawn before it reaches the Aral Sea. There are other rivers in addition to the Amu Darya where this is true, and one is right here in California. The Colorado River, which drains a large portion of the American southwest and forms the border between Arizona and California before entering Mexico [MAP] , no longer reaches the Gulf of California. Almost all of it is abstracted before reaching Mexico, and the rest once it crosses the border. The other problem with Amu Darya water--that it = s so contaminated with agricultural chemicals that it really shouldn = t be used on living things Β is also true of the Colorado. The problems of the Amu Darya arose because of Soviet central planning. The problems of the Colorado arise because it = s an international river basin. The water is going Β or would be going Β to Mexico unless it = s used here first, and the US has little compunction about making the fullest possible use of the water before that happens. This raises the problem of international river basins in general. Of the great river systems of the world, some, like the Yangtse and Yellow rivers of China and the Mississippi-Missouri system here, are completely contained within the borders of one state, but most of the big river systems are international rivers. The Nile is associated with Egypt, but in fact it arises in Ethiopia and Uganda and flows through the Sudan first. The Tigris and Euphrates rivers are associated with Iraq, but they arise in Turkey. In Europe, the two largest rivers, the Rhine and Danube are international rivers, with the Danube flowing through a dozen countries. Every country in South America from Venezuela to Bolivia is part of the Amazon Basin. In Asia, the Indus arises in India before reaching Pakistan, and the Mekong arises in China but enters the South China Sea in southern Vietnam. As we saw when we were discussed ocean fishing, resource problems are much more difficult when there = s open access to that resource, when anyone can use part of it but no one can maintain possession or exclude others from it. That problem was solved, or partly solved, for fisheries within 200 miles of land with the Law of the Sea Treaty, but remains unsolved for open-ocean fisheries. As the situation on the Colorado tells us, something analogous occurs in rivers: when one country has exclusive control over the entire river, there = s a tendency not to ruin it completely, but when there is no one owner, there = s a contrary tendency for the upstream country to use the river to the fullest extent before its water gets away into another country. Notice that there
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Lecture 11 - Case study no. 2: International river basins I...

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