What exactly is a Persian wheel? Also known as Rahat (in Urdu), it's a simple water lifting device, where a number of small pots are attached to a long chain. Two gear wheels make up the system and as the first one is revolved, the pots each dip and swallow water from the well and soon after pours itself out to a metallic shaft which in turns empties into an intricate network of troughs that distributes water adequately through the cropped area. It is believed that the technology originated in Egypt and as world shrunk through extensive trading, it spread to India and China.
This is a photograph of water recharging done around a water source (like borewell). This is being implemented in some primary schools of the area.
(Image taken from the NASA page mentioned below) Several African basins, such as the Congo, Zambezi and Nile, show significant drying over the past five years. In the United States, the Mississippi and Colorado River basins show water storage increases during that time.
In July 2007 India Water Portal collaborated with Chitradurga All India Radio (AIR) station (FM 102.6MHz) to produce and broadcast programs related to rainwater harvesting and ground water management. This activity was part of the 'offline' dissemination program of the Water Portal , i.e. creating awareness related to water issues through different offline media. We feel that the program series is a success and would like to reproduce the experience on a larger scale. The series -- named Mayadanta Male (literal , Magical Rain) involves 15 programs of 30 minutes duration each.
Mr. R.V. Rama Mohan of Center for World Solidarity has come up with freeware (an Excel spreadsheet) to calculate the groundwater extraction vs. recharge in an area. He has made the software available to the public and is soliciting feedback.
The September 2007 report of the Expert Group on "Ground Water Management and Ownership" of the Planning Commission is available from the Commission. The report looks primarily at the problem of rural depletion of groundwater and feasibility and necessity of changing groundwater law.
Attached is an interesting document from Prof. Prithvi Kandhal about using porous asphalt in parking lots so that rainwater seeps through it and recharges groundwater.
Dr. Kandhal has published many papers and has significant credentials in his areas of expertise. He resides in Jaipur after 35 years of working in the US.