Scientists have discovered that ground water levels in Northern India have been declining at the rate of approximately 33 centimeters (1 foot) per year over the past decade. The water disappeared between 2002 and 2008 is enough to fill lake Mead, the largest man made reservoir in the USA, three times. The researchers concluded the loss is almost entirely due to human activity. The water is being pumped and consumed to irrigate cropland.
The finding is based on data from NASA's Gravity Recovery and Climate Experiment (Grace) satellites. These two satellites orbit 483 kilometers above the earth's surface and change their relative positions in response to variations in the pull of gravity. Changes in underground water masses affect gravity enough to provide a signal that can be measured by the Grace spacecraft.
Using Grace Satellite observations, scientists can observe and monitor water storage changes in critical areas of the world from one month to the next, without leaving their desks. In developing countries, where hydrological data are both sparse and hard to access, space based methods provide perhaps the only opportunity to assess changes in fresh water availability across large regions.
Classroom Strategy:
Students in groups of four can do a project on the following research questions:
1. Satellites are serving mankind not only in predicting geological, and climatic conditions but also in searching more about space. Find at least ten more inventions of science and technology which serve mankind and how?
2. What other human activities have resulted in the depletion of natural resources?
Students can make power points, type a research paper or create posters on their research questions.
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