| The chopper at the Bihar Flying Club helipad and (below) the helicopter on its maiden survey. Pictures by Deepak Kumar
Danish geophysicists will now provide residents of the city with what they are thirsty about — potential sources of clean drinking water.
In a unique project, a team of two geophysicists from Denmark working in association with CSIR-National Geophysical Research Institute (NGRI) and Central Ground Water Board (CGWB) on Wednesday launched the maiden airborne survey to map the deep and shallow aquifers in seven blocks of Patna district. The inaugural flight of the helicopter-borne SkyTEM geophysical instrument went on air at the apron area of Bihar Flying Club, Patna airport.
SkyTEM (TEM — transient electromagnetic measurements) sends electromagnetic waves to the ground and depending upon the extent of penetration of the waves in the ground, the system gives assessment of the aquifer structure and water table composition up to 400 metres underneath the earth’s surface.
“Aquifer India Mapping Project (AQUIM), a World Bank-funded project, was launched on a pilot basis in July last year. CSIR-NGRI has collaborated with Denmark-based Aarhus University for SkyTEM heli-borne surveys whereas the CGWB is working on hydro-geological aspects in six places identified in Tamil Nadu, Karnataka, Maharashtra, Bihar and Rajasthan. SkyTEM would cover an area of 120sqkm in Patna district. The outcome of the heli-borne survey would be supplemented with limited ground study,” said Dipankar Saha, CGWB-Patna regional director.
Attached underneath a helicopter, the SkyTEM system is fitted with a generator for power supply, transmitter to send electromagnetic waves, GPS for location measurement and receiver for absorbing the electromagnetic waves reflected from earth’s surface. Based on the data given by the system, the software generates 3D geological map of the aquifer in the selected location.
Since its launch in 2003, SkyTEM system has been used by engineers and environmentalists for aquifer mapping in Australia, Malaysia, Norway, Greenland, Italy, Germany, Holland and France.
Rasmus Teilmann, project manager, SkyTEM Surveys APS, said: “The cost of the entire SkyTEM equipment (excluding the helicopter), which weighs around 700kg, is around 100,000 Euros. The system is more cost-effective, accurate and faster than the traditional means of aquifer mapping done through manually drilling in the ground at close intervals. Based on the visibility and weather conditions, we intend to complete the aerial survey within a week.”
Anshuli Arya, secretary, public health and engineering department, asked: “Would the data generated by SkyTEM aerial survey also give assessment on contamination of groundwater such as arsenic, fluoride and iron among others?”
Rasmus replied that the system would not give information on quality of water or its contamination.