Britain is blessed with some of the world's most beautiful natural waterways. They play backdrop to unforgettable scenic walks and picnics in the sun. We can hike alongside them, take bracing dips in them and spend relaxing days paddling on them in kayaks.
According to the WWT, 1% of the earth's surface is made up of freshwater ecosystems. In Britain, as well as having huge ecological importance, many hold great historical and economic value.
What's the difference between a stream and a river?
Generally speaking, a stream is smaller than a river. A river is a moving body of water – usually freshwater – that flows from its source across land into another body of water. A stream, which can also be called a brook or a creek, is a natural flow of water that follows a more temporary path.
According to the conservation charity Freshwater Habitats Trust, a stream is shown as a single blue line representing a waterbody less than 8.25 metres wide on Ordnance Survey maps.
It also says that streams:
- Usually having a sinuous, winding form
- Do not follow field boundaries – or if they do, pre-date boundary creation
- Show a relationship with natural landscape contours
Streams are less likely to be polluted than rivers, and pristine, clean streams can be important habitats for young trout and salmon. They can also host our native crayfish, which have otherwise been wiped out in rivers by the introduction of the non-native North American signal crayfish.
What is a chalk stream?
Things get a little more confusing when we think about chalk streams. Chalk streams are actually rivers that boast pristine, nutrient-rich waters.
The pure, clear water comes from underground chalk springs. It flows across flinty gravel beds and is home to many wild creatures that breed and thrive in them.
There are only about 200 chalk streams in the world: 85% are in England and most of these are in the southern half of the country.
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What is the longest river in the UK?
The River Severn is the longest river in the UK, at at 220 miles (354km) long. The Severn estuary makes up the last 40 miles (64 km) of its total length. It's a remarkable waterway stretching from Pumlumon (Plynlimon) mountain in Wales to the Bristol Channel with a tidal bore that you can surf.
The River Tay (120 miles, 193 km) is the longest in Scotland, the River Bann (80 miles, 129 km) in Northern Ireland and the River Tywi (75 miles, 120km) is completely in Wales.
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Main image credit: Getty Images