The first 3D geological survey and investigation map of Beijing showed that 76 sites of landfill refuse may pollute the city's ground water in the near future after the South-to-North water diversion project goes into effect in 2014.

The 44.5-million-yuan 3D map, that took four years to research, revealed the underground situation of 8,400 sq km of the city.

The 3D map showed that the city currently has 3,636 tons of landfill refuse, covering 10.77 million sq m of land. The South-to-North water diversion project, which is expected to complete its Beijing section in 2014, will elevate the ground water level and cause possible contamination to underground water.