Look at a map and you will see that the Thurne appears to rise just behind the costal sand dunes at Horsey and travel inland for six miles before joining the Bure and eventually making it to the North Sea at Great Yarmouth. It seems like a really long way round but it’s an interesting tale of costal erosion and man made landscape manipulation.
2,000 years ago the Thurne flowed into the North Sea through a big delta, where it now appears to rise. Winterton and Martham were on the south shore and Ludham and Hickling, the north. The villages of Horsey and Waxham were probably islands. Further up the coast erosion of cliffs, at what is now Happisburgh, slowly blocked the mouth with sand. Unable to escape, the water created a stagnant, bog, which the sea would have inundated every fifty years or so. It would still be like that if man hadn’t turned the river around and sent it inland to find and join the Bure.
Banking a river and creating a barrier causes the water level to rise. If it can be raised several feet above the surrounding ground, and as long as there are channels for it to flow the way you want it to go, then gravity will do the rest. If the sand bar is planted with marram grass, dunes will build up and the sea can be kept out, more or less, permanently. Slowly land can be reclaimed. Over time, and with the arrival of wind pumps from Holland, drainage became more efficient. Wind powered pumps were replaced by steam and now water is pumped up from the the land into the river by electricity. Today the source of the river Thurne could very plausibly be said to be a small brick electric pump house mid-way between Horsey and West Somerton, on the Hundred Dyke. In fact I think there are probably lots of beginnings to the Thurne, water from Somerton, Martham Broad, Horsey Mere, Waxham Cut and Hickling Broad all flow into it.
I had a crash course in drainage and water levels, at Horsey, on a beautiful morning in late September. I now know the difference three inches of water can make in a flat landscape. I know how a broken pipe has the ability to, and nearly did, empty the mere. I can see the correlation in water levels and land levels, counter intuitively, here it’s the aggressively farmed land that is lower than the boggy ground. But most of all I learnt that if you keep your dykes full, all the blessings of the natural world will be yours. I saw red deer stags, almost invisible but for the tips of their horns in tall reeds, skeins of pinkfeet geese noisily moved across the sky, cranes ruffled their bustles in the breeze and a kaleidoscope of dragonflies were making whoopee while the summer lasted.
