It is not difficult to summon in the mind’s-eye a classic English chalk stream: fairy-like mayfly glint in the evening light as they climb up through the fresh still air, they fall back through the forming mist to the crystal-clear river below, only to rise once more in their ‘spinners’ dance. Brown trout break the surface to snatch those that float exhausted on the swirling eddies. A fleeting life now spent. The shallow cool water races over a gravelly bed, weaving through thick patches of aquatic vegetation that waves constantly in the fast-flowing current. In a nearby buttercup-speckled meadow a herd of cows lazily rip at the dew-soaked grass. A grey wagtail darts about their hooves, beak full of flies, it flicks its metronome tail to the beat of the river. My sudden imaginary presence startle a water vole which dives with a loud ‘plop’. And with a glimpse a kingfisher’s perch is emptied, sending an electric blue streak downstream. 

My rather romantic description may seem like some dreamy erstwhile vision, but it can be the reality of our beautiful and internationally important chalk-stream rivers with proper and continuing protection. 

Of the 210 rivers worldwide, that are classified as chalk-fed, 180 are in Southern England, with 25 in Norfolk – of which the Mun, Ingol, Heacham and Glaven are of global importance due to their assemblages of plants and animals. The Whitewater, a tributary of the Wensum, dissects NWT’s Hoe Rough and Beetley Meadows reserves and is nationally important for the native, white-clawed crayfish. It is also home to a rare variant of brown trout that, due to their isolation, have developed into miniature examples of the species. The Whitewater’s confluence with the Wensum means it joins the longest and most significant Norfolk chalk stream. The Wensum is familiar to many due to its course through Norwich, with it caressing the boundary of NWT’s newest nature reserve at Sweet Briar Mashes. After passing through the city, the Wensum joins the Yare which takes all the credit for carrying one of the country’s most important wildlife-rich rivers on its final leg to Great Yarmouth and out into the North Sea. 

Norfolk’s chalk-fed rivers rise up as springs in the woods, meadows and mires on the western side of the county, where the underlying chalk sits. It is astonishing that this soft white rock is the crushed and compacted remains of countless trillions of ancient microscopic sea creatures. Eons of time and geological upheavals mean that there are few places where huge beds of chalk lay close to the surface, southern England being one of the few. Rainwater that fell decades ago percolates up through the huge underground chalk aquifer, being purified and enhanced with rich minerals. The dissolved calcium allows a variety of molluscs and crustaceans to thrive in chalk-fed rivers, with many being unique to this rare habitat. The emergence of chalk streams from deep underground means that they remain at a fairly constant temperature year-round. This favours a diverse array of aquatic plants, including several species of water crow’s-foot. At the right time of year, it can cover parts of the river with a wonderful carpet of white and yellow flowers. Bullhead, brook lamprey, Atlantic salmon, and my personal favourite, banded demoiselle are strongly associated with chalk stream rivers. 

Sunday the 22 of September marks World River’s Day. It is designed to be a celebration of the world’s waterways, with its purpose to highlight the value of our planet’s rivers by encouraging and supporting schemes to improve and sustain them. Many of the projects focus on the world’s great arteries, and the problems facing those that rely on them; rivers such as the Amazon, Nile, Indus and Yangtze. But closer to home, our English chalk streams face their own threats. Toxic levels of sewage and agricultural run-off, unsustainable groundwater abstraction and damage to our wetland landscape has left our rivers in desperate need of help. Norfolk has over 420km of chalk rivers and streams but the health of these world-renowned habitats is at great risk. If we want healthy rivers, then action must be taken. 

Chalk streams rely on a healthy aquifer (the body of water that is held underground within the porous chalk rock) and water abstraction from it can dry out these already naturally shallow rivers. Agricultural fertiliser run-off and sewage can green the water with blooms of algae. Slurry accidents and industrial chemical spills are still occurring and cause devastating destruction of these carefully balanced eco-systems. There is also the rarely mentioned, but ever present and continuous pollution from the chemicals and rubber that is carried off our roads by rainfall, this ends up seeping into the groundwater and rivers, its significance is only now being properly understood. These seem issues from a less enlightened age, but astonishingly they are increasing and posing a real threat to all our rivers, not just our rare and globally important chalk streams.          

Ending water pollution and water scarcity is one of the three priorities included in Norfolk Wildlife Trust’s Plan for Nature which sets out the action our government must take to halt and reverse the collapse of the natural world – and ensure nature is thriving and abundant. We set out the need to halve nutrient pollution from farming, sewage and development by 2030; for more investment in creating and repairing wild habitat; and the need to invest in a holistic approach to managing water resources in Norfolk.  

And we are actively improving our rivers where we can. Groups of volunteers have helped create pools and riffles from shingle banks, faggot beams and statically placed logs. They have also helped re-plant areas with reed and wetland flora. Larger projects have returned rivers to their original course, undoing the unnatural straight lines of our modified rivers and reuniting them with their floodplains. This floodplain connectivity is not only good for nature, but a better solution for the increasing occurrence of flooding in our lowland areas.   

There is still a lot of work to be done, but World River’s Day must remind us of the unmeasurable value of our wonderful, beautiful and precious Norfolk chalk streams – and we must do all we can to protect them.  

Read Norfolk Wildlife Trust’s Plan for Nature here: www.norfolkwildlifetrust.org.uk/priorities