Penrhos Home PagePenrhos home page site mapSite Map permaculture design at penrhosPermaculture Design at Penrhos

back to water management

 

A brief and partial overview of upland water management.

 

Holistic or integral water management in Britain...

The simplest description here is that there isnít any. More accurately, water management is fragmented between a wide range of organisations, public bodies, businesses, land owners, users and consumers, often seen as competing in their interests. The result has been a real lack of any "joined up thinking" regarding water management and usage and thus great difficulties in developing holistic solutions or indeed any overall, coherent strategy; the challenge is approached piecemeal and seen from many, limited perspectives. Working without an overall or integral perspective leads to inevitable confusions. For example, a local landowner recently suggested that as he has heavy machinery, he could easily straighten and deepen the river on his land in order to get rid of flood water more quickly. Yet rapid removal of water from the landscape is not what is required in order to cope with periods of intense drought.

At present, emphasis is still placed on dams and reservoirs as the main techniques for storing water. These are seen as being fed by rainfall running off the land and into them. Ditching is often undertaken above dams and reservoirs in order to increase the run off. The construction of dams and the drowning of valleys and even villages has enormous local consequences that reverberate through environmental, social/cultural and individual spheres of influence.

Past (and unfortunately present) land practices have tended to increase run off. Deforestation has taken place throughout much of Britain over the last several thousand years with wide variation in scale and timing depending upon the locality. The south eastern corner of the country was largely cleared by the end of the Roman occupation (say about 400AD) whereas other areas persisted for much longer. Mynedd Penrhos, for example, the land which includes our own holding, is recorded as being clear felled of oak around the turn of the 17th century, though whether this was the original "wild wood" is not clear. It then remained an open common until it was occupied and developed by subsistence farmers.

The initial enlargement of sheep grazing seems to be linked to the growth of monasteries in the eleventh and twelfth centuries. Monks developed various innovative agricultural techniques that led to improvements in methods that increased yields. Their work with fish farming is particularly interesting and it seems that they understood and accepted the fact of river flooding rather than tried to stop it. So rather than the levies along the banks of the middle Mawddach being intended keep flood water off fields, they were designed to trap flood water on fields so it could deposit its silt and nutrient rich burden there, rather than carry it off and out to sea. There is also the likelihood that these flooded fields may have been stocked with a temporary fish crop. A similarly interesting suggestion is that in winter the presence of water would keep the temperature up enough to avoid frosts and so keep the soil temperature higher and allow grasses to keep growing, providing an early bite in the spring.

However, whether or not the monks were initially responsible for the extension of grazing into the uplands and even the mountains, it is a fact that today most upland areas are still subject to extensive unfenced grazing by sheep, thus tending to minimise any regeneration, especially of trees, and maintain a sheep lawn with little potential for trapping and infiltrating surface water run off.

 

Extensive grazing

During the Second World War, the British Government placed the economy on a war footing. This included, among other things, the introduction of subsidies to farmers to encourage them to bring more land under cultivation and grow more food. When the war finally came to an end (1944-45) a decision was made to maintain the war economy and continue to pay subsidies to farmers. This war economy persists today and it could be said that we turned our warlike attention on nature.

Subsidies were initially based on production; money was paid according to the number of livestock your land could support or the acreage of grain or other crops. With regards to livestock, this prompted the movement to "improve" grazing through ploughing, reseeding, drainage of wet fields and the application of chemical fertilisers, thus increasing the stocking capacity of the land and hence the size of the subsidy.

Large scale drainage of upland bogs including raised bogs continued unabated and was seen as "a good thing" until the mid 1980s when the importance of these natural systems was finally recognised officially and environmental subsidies first began to appear to maintain these habitats. At this time the emphasis on these systems placed their value in terms of ecology and habitat rather than water management but by this time, many upland bogs had already been drained.

The increasing incidence of longer and longer periods of dry weather has an important effect. Peat, once dry, is extremely difficult to get wet again, as anyone who used to grow seedlings in peat filled pots will be aware. Dry peat requires a long period of soaking to gradually regain its water holding capacity. Local observations and speculations suggest that repeated periods of drought followed by rain may well result in layers of wet and dry peat that resist movement of water downwards and prevent further absorption.

Further evidence from research by a local scientist, Graham Hall, identifies crucial differences between older, humified peat and active sphagnum bog. From the point of view of flood prevention, the former provides very little buffering in high rainfall conditions.

Generally then we have encouraged the removal of water from the system as rapidly as possible- at best into dams and reservoirs, at worst (more likely) into rivers, drains and thus the sea (ie the water is rapidly lost from land based systems). Run off increases erosion; as speed of flow increases so too does the amount of debris which can be carried (and therefore the amount of materials lost from the land based system). These result in increased silting of rivers and estuaries.

The challenge is heavily compounded by increasing temperatures and reduced rainfall, or rather, annual rainfall becoming far more concentrated at specific times of the year and specific rainfall events (flash floods) with periods of extended drought between. Both these observable phenomena are closely related to soil erosion; as the land dries out and vegetation fails leading to bare areas and surface cracking, soil is subjected to damage from the feet of grazing animals, breaks up and crumbles. Heavy rain, slow to penetrate the dried out surface, runs off carrying soil particles with it and turning the rivers brown. The erosion is much worse on slopes.

 

"Get rid of water more quickly"

This is still generally the mind set embedded in our actions. In fact the exact opposite is what is required. The landowner would be better off studying the natural formation of rivers and observing in particular the way flood plains develop as temporary water storage to trap materials and allow water to penetrate into the soil rather than just disappear from the system.

Anyone seriously involved in developing sustainable environments and communities, such as permaculture designers, need to give attention to exactly the opposite approach, namely how to slow down the movement of water through landscapes, holding on to it for as long as possible and getting it to do useful work.

back to water management

Penrhos Home PagePenrhos home page site mapSite Map permaculture design at penrhosPermaculture Design at Penrhos