The Summer Dyke
Small but beautifully put together - the summer dyke
If we look carefully around today's dyke foreland, e.g near Haffen, between Bienen and Grietherort or near Hüthumum, we can see the flat dykes that criss-cross the landscape. They are summer dykes that played an important regulation role for agriculture on the Lower Rhine. Dykes protect against floods. In the winter, the floods were actually desirable for farming. Before there was such a thing as man-made fertilisers, the Rhine flood waters brought nutrients that made the soil fertile. But not all floods are the same. If the arbitrary moods of the floods were not stopped during the cultivation period, it would be impossible to use the river meadows. Even slight rises in the level would spread out over large areas in the flat surrounding countryside and destroy the harvest and livestock. The flat summer dykes helped against the threat to the cultivated land. They had to be high enough to keep the low summer floods out but low enough for the higher winter inundations to be able to do their important flooding work. Sluices let the winter flood in and out again. The inhabitants built the farms behind the dyke on artificial earth mounds. If the Rhine floods the summer dyke and covers the land behind it, at least the house and barn remain dry. The livestock is then safely stabled and the harvest has been brought in. There was enough time to do that - thanks to the summer dyke!
Today, targeted field fertilisation is possible, which is why the farmers can dispense with the winter flooding. The only inundation happens when a flood breaches the summer dyke. But since the Rhine is becoming deeper due to its current, these incidents are becoming rarer. This is causing difficulties for specialised animal and plant species in these recurring floods because they are being displaced by other species over the course of time.