Robbing Peter to Pay Paul?

Floods and Floodplains: Robbing Peter to Pay Paul?

We are lucky enough to have some flower-filled wet meadows, and over the last seven years have worked hard to improve species diversity, mainly by cutting the vegetation in mid to late summer and raking it off. The aim of this is to keep nutrient levels low and open up the vegetation so that some of the smaller plants and their associated creatures can thrive. What happens without this management is clearly demonstrated by the ‘Bayfield Lower Meadows’ just to the north of Natural Surroundings, where the area to the west of the river is hard to access and very wet – even the Highland Cattle stayed away. After years without management this area is now completely dominated by tall plants, especially Great Willowherb and Common Nettle, which have crowded out most other things. Our meadows are wet due to ground water – even in the driest summer you can dig a hole and if it is more than 25cm deep the bottom will fill with water. This ground water presumably seeps down the slope from the hills to the east of us, which are wooded, although some water may percolate down from the plateau above the woods, which is a mix of arable and pigs. The source of the water that keeps our meadows wet is an important point; it is definitely not river water.

Staying with water, levels in the River Glaven are high again as we get more and more rain (and even snow on 16th January). As I stand on the riverbank and watch the murky water rush by, I find myself hoping that it doesn’t get too high, that it won’t spill over the bank onto our meadow. The reason is simple. When in spate the Glaven carries a lot of silt, hence the murky colouration. The silt is there because it is washed out of the fields and into the drains and ditches that feed into the Glaven upstream. Some landowners are very mindful of this and do what they can to keep hold of their topsoil, but others are, it seems, less bothered.The sugar beet harvest, which carries on whatever the weather, does not help. The heavy load of silt in the Glaven is certainly not great for the river, as our ‘chalk river’ has large banks of mud in many places. Neither is it good for our meadows: every flood will raise the level of the land a tiny bit more as the water spreads out, slows down and drops its load of silt, elevating our meadow a little bit higher above the summer water table. It is, however, what’s in the water and silt that is of greater concern – the phosphate, nitrates and pesticides from the fields and who knows what from Holt Sewage Works. Those phosphates and nitrates would seem likely to undermine our work to reduce fertility, and it is anyone’s guess what effect the pesticides, hormones etc. have? The news that neonicotinoid pesticides can be used on sugar beet in 2021 does nothing to reassure us!

Yet … reconnecting the river with its floodplain is promoted as a GOOD THING. As I look at the murky water, I can see that this is indeed likely to be a good thing for the river itself, especially if it is in a poor state of health, as the floodplain will act as a ‘sponge’, mopping up silt and filtering out some of the nasties before the floodwater returns to the river. But, unless the river is clean and healthy to begin with, it is hard to see how this can be a 100 per cent good thing for the floodplain, and especially for the smaller and more vulnerable plants and their friends that live there. As usual then, the real-life situation is more complicated than may seem at first sight, and the virtues of ‘reconnecting a river with its floodplain’ are not so straightforward. It’s a dilemma, and I would be interested to know if there are ways to benefit both river the floodplain?

When the Glaven is very high it comes over its banks and rushes through the woods to our meadows