On my way to the office I cross tributaries flowing into the river Blyth, one of which forms a boundary to our garden. What is apparent this year is that a huge amount of silt is being deposited in these rivers and streams.
This autumn has been incredibly wet, with flooding in many parts of Britain (although less in East Anglia). I am sure that one of the reasons for the increase in flooding is the deep drainage of so much farmland: as the water runs off it takes with it a significant amount of topsoil.
On one occasion, when the water level subsided in a beck running through our fields, I found that it left behind a deposit of high quality sandy loam. (Which I am bagging up for seed beds in the garden.)
Some farmers plough in the autumn, leave the ground fallow over the winter and then sow in the spring. Other farmers, on the other hand, prepare ground in the autumn specifically for an autumn sowing, and it is these farmers that have been hard hit by the weather this year.
Either they drilled into wet ground – and have had poorly established crops as a result – or they simply didn’t get a chance to drill because the weather didn’t allow it. The result? Compared to previous years, there is more farmland this winter with little or no ground cover.
The worrying aspect of this is the huge quantity of both water and topsoil that is running off the surrounding farmland.
Another factor causing flooding is urbanisation. A vast acreage of roads and drives pours water directly into drainage systems that empty into rivers.
Not so long ago all this water would have fed into groundwater, into aquifers and flood plains. But now it is going directly into the river system and causing floods. So that, combined with climate change, suggests that the threat of rising water levels is becoming a reality, and a scary one at that.
These are the issues that World Land Trust’s (WLT) partners are addressing in many of our land acquisition projects. Protecting watershed, particularly in montane areas is a priority. It not only conserves clean water supplies, it also helps prevent erosion, mudslides and siltation of rivers. And these sorts of benefits can be readily valued –‘monetised’.
But siltation is not all bad.
Otters leave beautiful clear footprints in the fine muddy silt; and it’s satisfying to see that the results of a sustained conservation effort mean we now have otters, actually in our garden. When I was writing about the decline of otters 35 years ago for New Scientist magazine, I would not have thought it possible.