There are 210 chalk streams in the world, 160 of which are in England and the River Nar is one of them. What makes them so special is that chalk is porous and rainwater falling on these hills doesn’t run off in torrents, it percolates through the ground to springs lower down. Chalk hills act as aquifers, they store vast quantities of water so that chalk streams have a famously stable flow and temperature. Rain water is naturally slightly acidic and chalk is soluble in rainwater so that the spring water emerging from chalk hills is alkaline and mineral-rich. The results are gin-clear streams which support complex ecosystems. Amongst other things they have a mythical status amongst dry-fly fishermen for their large populations of wild brown trout.
Chalk streams are lowland streams. They are fertile life giving places that have supported thousands of years of human settlement. We have been sustained by them and more recently we have abused them terribly. The Nar was made navigable in the mid eighteenth century with a series of sluices, locks, banking and dredging work all the way to West Acre but a century later the King’s Lynn to Dereham railway had killed it’s commercial viability. Chalk streams receive the same pollution we gift to all our waterways but they suffer more than other rivers from over abstraction of water. Not only is water taken directly from them but from their aquifers as well. The famously gushing springs at Houghton-on-the-Hill dried up after Anglian Water sunk a bore hole into the aquifer. What was once recognised as so precious that people chose to worship by it, is now a commodity which all 70 million of us think we have a right to use so carelessly every day. A chalk stream ceases to be a chalk stream if the flow of water is compromised and if the flow is compromised too much it’s temperature will fluctuate and it’s ecosystem will eventually fail.
But enough of the doom and gloom, the River Nar is lovely. It’s been officially recognised as a Site of Special Scientific Interest and the The Norfolk Rivers Trust have just completed a three year restoration project at Castle Acre. I walked downstream and drew on the edge of the River Nar Long Distance Footpath. I didn’t see a soul all afternoon. The river flows flat and silent here through a shallow reedy valley, only betraying it’s impatience with the vaguest swirl of a current on the surface. Fish rose and belly-floped back into the water, the green of new reed growth electrified the banks and smooth toped clouds proposed above it all. A hot April afternoon spent drawing on the banks of the River Nar is about as perfect as it gets.