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WET System
Coed Hills Wetland Ecosystem Treatment (WET) System
The Wetland Ecosystem Treatment (WET) System is a fantastic example of permacultural principles in action, fulfilling several roles in a way that is beneficial to the environment. The system is able to clean waste water naturally, provide willow coppice as a material for use in crafts and create a wonderful, rich habitat for plants and animals.
There are 20 different varieties of willow growing here, along with reeds and grasses that gradually purify the water as it flows through the 4 swales to the existing pond. Each of these develops into a thriving ecosystem and a beautiful habitat for wildlife.
The fast growing willow can be partially cut on a regular basis (coppiced) and makes a great resource for crafts such as basket weaving and sculpture, bark boxes as well as biomass for heating. Examples of living willow structures can be found in the ‘Medicine Wheel’ in the Crofter field and around the original compost toilets and greenhouse.
The creation of the WET System allows a very diverse population of plants and animals to ‘move in’, and will be a boost to local bird and insect life as well as the varied plants in a wetland environment. The WET System is designed to harness the water-purifying power of nature to treat effluence while providing a lush marshland habitat for plants, insects, amphibians and birds.
A series of swales (or large ditches) are dug, each one slightly lower than the one preceding it, culminating in a pond at the bottom. Along the banks of the swales a plethora of water-loving plants are planted. As the effluent water passes through the banks of the swales, sediments and pollutants are removed by the plants and micro-organisms. By the time the water has passed through all the swales and reached the pond it is considered clean, we actually over-engineered by digging a few extra swales just in case.
Designed and installed by Biologic Design and Coed volunteers, the project has been supported by Environment Wales and Carillion.
Westons Cider had one built a few years ago do deal with their waste water and brought some people in to do a wildlife survey; after only a year they recorded 20 new types of bird to the new habitat, and increase of 50% from the original 40, which gives an indication of how the rest of the web of life has been affected.
Work began in January 2009. First, the digger was brought in to dig the swales and prepare the land. Once these were dug, several tonnes of waste wood from a saw-mill had to be chipped to produce a 1-foot deep cover over the earth. This would act to inhibit growth of plants and provide a nitrogen-rich habitat for micro-organisms within the swales.
The chipper became affectionately known as "The Mouth of Sauron" for its seemingly limitless appetite and ability to devour and destroy everything we could feed it; for three days we felt little but slaves to this monstrous machine. After the first half an hour-or-so it no longer felt like we had ear-defenders on at all.
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Once the chipping was complete the site was tidied up and leftover larch used to line the banks of the swales for a little visual effect, even though once the plants have gone in they will be swamped with green.
