by Barry Deakin

I grew up in Devon, close to a water meadow which was simply a wet meadow with drainage ditches cut along it to help dry it out for grazing. When I moved to this area and saw the arrangements of weirs and hatches in the Avon, and gates within the meadows to enable control of the water levels, I realised that our local meadows were managed more actively. I didn’t appreciate their complexity or value to agriculture though, until I came across a collection of scientific papers on the subject: “Water Meadows – History, Ecology and Conservation” Edited by H. Cook & T. Williamson.

Unlike the passive drainage that I saw in Devon, and other systems designed to irrigate land, the primary function of the systems in the Avon valley and other chalklands in Wessex was to raise the winter soil temperature. They were developed in the 17th century to enable controlled “floating”, with a thin, moving film of water, evenly distributed over the meadow, to hasten grass growth in early spring. This was achieved with a weir to gain a head of water, a hatch to control flow into a carrier ditch which in turn fed a series of small channels, each cut in the crest of a ridge formed in the meadow. Many such ridges were created in parallel, separated by drains that returned the runoff to the river. Creation and maintenance of these earthworks required a huge investment which seems difficult to justify without an understanding of the benefits, beyond the obvious one of bringing forward the early grazing when hay might be running short after a hard winter.

In our region of chalk downs, from the 17th until the start of the 20th century, the primary aim of the landowners was to grow wheat and barley. The chalk soils are very thin and poor, so sheep were moved from their day pastures to manure the arable land at night. The grain productivity was limited by the size of the sheep flock, and this in turn was limited by the number that could be sustained over winter by the hay crop, until spring grazing was possible.

Floating the meadows with river water protected them from frost and maintained the soil temperature above the critical 5oC required for grass growth, bringing their grazing potential forward by several weeks. It was usually carried out repeatedly for a few days at a time from late December until early March. Sheep were then grazed for a couple of months, after which another period of floating irrigated the meadows to encourage a rich summer crop for hay. This in turn gave more winter feed, further adding to the potential flock size. As well as these benefits, the lime content of the Avon and its fine sediments both increased the fertility of the meadow soils, and other chemical effects favoured the more palatable grasses. It was vital though, to avoid pools of stagnant water which are harmful to grass growth, so the levels and gradients of the earthworks required precision engineering.

Development of water meadows had the potential to double the agricultural value of the land, so all of the chalk valleys of Wessex had been developed by the middle of the 18th century, and the “drowners” who maintained and controlled their flow were men of great importance in the farming community. The developments caused many disputes though, notably with millers, many of whom were paid some compensation and agreements reached, often through the courts, regarding the precise periods when their supply would be cut.

The geography of our area was particularly favourable. The river gradient, wide flood plain, and relatively warm water issuing from the chalk all played a part in the cost-effectiveness of the local meadows.

Few of the meadows have been maintained through the 20th century but those at Harnham have been the subject of a great restoration project and are again being floated. Various changes in agriculture caused their decline. Construction of the railways enabled milk to be conveyed quickly to towns and increased the value of dairy farming, artificial fertilisers replaced the need for sheep folding on the cornlands, new strains of grass and other types of fodder supplemented meadow grass, labour costs increased and, most significantly, cheaper grain was imported from America. It is interesting that scientists have only recently gained a full understanding of how productivity was increased, long after the demise of the meadows. Their value now may be in their archaeology, and certainly as a wildlife habitat with much greater biodiversity than when they were managed as intended. Many are of course included in the Avon valley SSSI.

The scale of the engineering works is evident, with examples across the whole of the floodplain. In Woodgreen the size of the channel between the road and the river below Hale Park is impressive and this was a feeder supplying the meadows between the village and the river. It no longer carries any flow, having been blocked by infill at the edge of the village.

These notes barely scratch the surface of the subject and I recommend the collection of papers referred to earlier for a fascinating education on it.

Aerial photo of the meadows at Burgate that I took in February 2001, when partial flooding revealed their extent and complexity.