First 109 words of the document:
Economic uses of chalk- Aquifers
AN aquifer is an underground reservoir of water stored in pores in the rock, e.g. chalk.
Aquifers form where the porous rocks are exposed at the surface. The rain water
percolates down through the rock to form a giant underground reservoir.
The London Basin Aquifer
> Clean, unpolluted
supplies that do not dry up during drought Disadvantages
> Bore holes sunk close to where required
> Finite supply
> Takes years to be replaced
> People cannot increase the storage