Search Menu Toggle
Close Menu

You are here : At Home > Save Our Streams > Chalk Streams

What are chalk streams?

Chalk streams are some of the most beautiful and rare stretches of water on the planet.

England is home to over 85% of them

Many of these chalk streams are found in the South East of the country.

The water found in chalk streams is beautifully clear, pure and rich as it is filtered as it rises up through the chalk before flowing down into the chalk streams in our area. This makes chalk streams the perfect home for a variety of fish, birds, plants, and small mammals.

Show more

do chalk
come from?

Chalk streams are rare

Did you know that of the 260 true chalk streams on Earth, 224 of them can be found in the English countryside? This makes them rarer than the Bengal tiger, and they need to be protected.

Chalk streams are home
to wildlife and plants

The clear water also makes for the perfect home for a variety of plants and animals, including, trout, the flag iris and several species of mayfly. Otters, kingfishers and water Voles all make their homes on the banks.

Show more

Why do

Where do chalk
streams come from?

Originating from natural areas of chalk bedrock like the Chiltern Hills, chalk streams are fed from the water held in the chalk underground. Chalk is an aquifer, which means that it can soak up and hold water. The water held in aquifers, feeds the chalk streams where it reaches ground level.

Groundwater levels, however, can decline naturally when there is lower than average rainfall.

Show more

The natural
water cycle

Why do chalk streams sometimes dry up?

Unlike the Bengal tiger, chalk streams don’t deal well with the heat.

During summer, rainfall typically doesn’t reach the chalk as it is mostly taken up by plants and lost through evaporation. The water table drops, and the head of the stream moves down the valley, potentially leaving the top layer of a chalk stream dry. This layer is called a ‘winterbourne’ because it only flows after the winter rains.

During the winter when temperatures are cooler and there is less plant growth, more rainfall typically filters through to the chalk. This tops up the aquifer and the head of the stream moves up the valley as the water table rises.

Because of this natural water cycle, during the summer and autumn months, some reaches of chalk streams can dry up. Although the wildlife and plants that inhabit winterbournes are used to these conditions, they can be negatively impacted by lower flows. We are working hard to reduce the amount of water we take to leave it in the environment.

We’re not asking you to invite a family of otters to stay, instead if we can all waste less water, we can help support these rare and impressive eco systems.

What are water tables and aquifers?

A water table is the boundary between water-saturated ground and unsaturated ground. Below the water table, rocks like chalk are full of water. An area’s water table can fluctuate as water seeps down from the surface.

Pockets of water existing below the water table are called aquifers.

Show more

Did you

Did you know?

On average, customers in our area use around 157 litres per person every day, compared to the national average of 145 litres. That’s about the same as 85 large cola bottles (and we wouldn’t recommend drinking that much).

Of the 260 true chalk streams on Earth, 224 of them run through the English countryside. That’s 85% of the world’s chalk streams!

The UK’s average annual rainfall is a sopping 1200mm but much of that four-figure average rainfall is propped up by the rainy highlands of Scotland, Wales and Northern England.

In the South-East of England, the average annual rainfall lingers around 500-600mm. That’s less than South Sudan, or Perth in Western Australia!

Find your

Take a stroll near your local chalk stream and explore your local environment.

How much
could you save?

My Water Footprint

Discover how you can save water and money in your home today.

Ready to order
your free

Take the short quiz to claim your free water-saving devices.

What are you waiting for?

It’s easy to help your local environment and Save Our Streams – it’ll only take you three minutes. Get involved and save water and money.

Start your journey today
Start your journey today
Enable Recite