Your drinking water and all of the water you use at home, from your taps to toilets, is supplied by local aquifers. These are the same groundwater sources that supply our chalk streams and rivers.

There are only around 200 chalk streams and rivers in the world, creating a habitat as biodiverse and unique as the Amazonian rainforest or Great Barrier Reef.

Here are five facts about chalk stream that you may not be aware of.

 

They’re globally rare – but mostly found in England

Chalk streams are incredibly unusual worldwide. Around 85% of all chalk streams on Earth are in England – with a quarter of them located right here in East Anglia. A few exist in northern France and small pockets elsewhere, but nowhere else has such a concentration.

 

Their water comes from ancient underground reservoirs

Unlike typical rivers fed mainly by rain runoff, chalk streams are spring-fed from aquifers stored in the chalk bedrock.

This means the water can take years, or even decades, to travel underground before emerging. It’s naturally filtered and very clear, giving chalk streams their famous sparkling appearance and exceptional water quality.

 

 

They stay almost the same temperature all year

Because the water comes from deep underground, chalk streams are thermally stable. They’re generally cooler than other rivers in summer and warmer in winter.

This stable environment is perfect for sensitive species like brook lamprey, grayling and water crowfoot plants, making chalk streams biodiversity hotspots.

 

They were historically ‘gardening projects’, not wild rivers

Many chalk streams have been heavily managed for centuries.

They have been divided into channels to control flow and maintained to support fly fishing and water meadows.

Although they look natural, they’re often the result of careful human engineering dating back hundreds of years.

 

They’re highly vulnerable despite looking pristine

Even though they look clean and healthy, chalk streams are actually very fragile ecosystems.

Over-abstraction can reduce base flow. Pollution is harder to dilute, because flows are steady but not substantial.

Climate change alters the recharge of aquifers, which makes them one of the most threatened river types in the UK.

We’re playing our part to reduce the amount of water we need to abstract. Working in partnership with Anglian Water, we're building a 25km pipeline between Grafham Water and Cambridge and investing in a new reservoir, called Fens Reservoir.

Together, these initiatives will help reduce the pressure on local groundwater sources and improve water resilience for years to come.

 

That’s why every litre of water saved – whether that’s through our efforts to reduce leakage and upgrading our pipelines, or our customers reducing their own water use at home, helps protect our local chalk streams, including the Cam.