EA Kent Water situation report just published:
http://www.environment-agency.gov.uk/static/documents/Research/Water_Situation_Report_KSL_December_2011.pdf
In summary, groundwater (i.e. aquifer) levels are 'notably' low at the moment right across Kent and are continuing to fall although there has been a slight rise noted in East Kent. Rainfall for December in the Dover District was over 200% greater than the Long Term Average, but it takes time for this water to seep into the groundwater to make a difference, i.e. heavy rains tend to run off rather than take time to permeate down and replenish the aquifers. It's worth remembering that river flows across Kent are also all below normal, this isn't just confined to the Dour. Local reservoirs are, however, showing signs of recovery.
The low levels are therefore just a natural phenomenon and are not down to increased abstraction rates by Veolia - indeed, water extraction rates are lower than they were ten years ago due to the introduction of water meters and more economical use. A sustained period of rainfall should see the groundwater (aquifer) levels slowly recharged.