| Unsustainable abstraction The water that flows in a chalk stream originates from surface run-off and aquifers. Aquifers are natural underground reservoirs. They rely mainly on autumn and winter rainfall to recharge them, so that if too much water is pumped out of the chalk aquifers, the river will dry up. Thames Water pumps 19 million litres per day out of the upper Kennet aquifers to meet the demand for water we use for drinking, washing and industry: water that would otherwise maintain the flow in the River Kennet. Once removed, much of the water is pumped outside the Kennet catchment to Swindon, so it never flows back into the River Kennet. In dry summers, this loss of water causes severe stress to the ecology of the river. In extreme years, the river dries up completely for long stretches, with disastrous consequences for the fish and wildlife. | 
