Through special satellite images made over the 2002-2008 period, NASA detected an average drop in groundwater levels of about 4 centimeters per year which may not sound like a lot --but added up represents the loss of about 110 cubic kilometers of groundwater lost during that period. Some estimates are actually a lot higher and have predicted a loss of about 54 cubic kilometers of groundwater lost yearly in the Indo-Ganenic plains, the worlds most densely populated and heavily irrigated region. Studies have indicated that the depletion rate is accelerating in the last decade by up to 70%.
Urbanization and industrialization take their increasing share of groundwater withdrawal, but estimates are that over 90% of aquifer depletion comes from larger farming operations mainly of rice, wheat and barley. India's soviet style planners egged on by the promise of a Green Revolution, have not given up on large, prestigious irrigation projects (usually involving big dams) serving hybrid seeds, despite their dismal consequences. All kinds of hybrid crop varieties that require large quantities of water, such as rice, sorghum, maize, cotton and vegetables, are still being promoted in the arid regions.
Due to deforestation higher up, the thinning in the icecap on the Himalayas (also due to climate change), and the decreased water absorption capacity of the earth that comes with industrial agriculture, monsoon rainfalls all to often result in sudden flooding in the valleys downstream without necessarily replenishing the aquifers themselves. Once the waters recede, they leave depleted soil and human devastation in their wake, increasing the risk of a repeat scenario in the following years. Continued fertility is at stake here.
One very significant effort in this regard is the work of Rajendra Singh, an expert on traditional water systems.
Rajendra understood that the secret to remediation of desertification is two fold:
-increase the aquifer levels underground
-plant appropriate trees at the edge of the desert for water containment and soil generation
Rajendra taught the farmers of the desert state Rajastan how to catch water in their johads, a system of rivulets and arroyos channeled into large and deep (up to 100 meters) underground water-storage areas that seep into the ground and recharge the aquifer underneath the desert. Participation in the program was successful enough to recharge several dry riverbeds into lively rivers and many wells. Whereas this year other areas in India were too dry to farm due to the lack of a monsoon spell, in Rajastan the effects have been relatively mild. Due to the communal effort and the insight of dr. Rajendra Singh the farmers of the Alwar district have to fear less for a bad harvests. Says Rajendra: "Unless you catch water it disappears quickly. Eighty percent of India's rainfall is just run off. Here too we have noticed too a decrease in rainfall, but through our johads we have saved enough water to bridge this spell of drought".
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