Clay lined pond fed by roof harvested rainwater.

The picture on the right shows what used to happen to the rainwater harvested by the barn roof. This barn can harvest over 470 cubic metres of rainwater annually. No drainage had been provided for this water so it went to waste and also created a mess. Changing the fall of the guttering, rearranging the down pipes and excavating a pond resulted in this resource being put to good use. In addition to improving conditions around the barn the finished pond seen below right was designed and positioned in such a way as to fulfil a number of other functions:

Source of fertility
Aquatic plants grow extreamly rapidly. This biomass is raked off the pond once a year and used as a fertilizer for adjacent horticulture.

Organic pest control
Adult amphibians such as frogs live in the pond and consume the slugs which are a pest on nearby vegetable production.

Emergency Water Supply 
The pond has a capacity in excess of 20,000 litres and an adjacent hardstanding which allows the Fire Brigade to class it as an Emergency Water Supply in the event of a fire.

Wildlife habitat
This pond was excavated into grassland of little diversity. Therefore the pond enhances the wildlife value of the farm.

Energy conservation
Future plans for the barn include the possiblity of it being converted to an educational centre. The barn would then have a southern elevation glazed for solar gain. The pond therefore was positioned so that it could reflect low winter sunlight through any glazing so as to reduce energy consumption.

This one pond well illustrates some important ecological design principles, the creation of functional relationships, the value of diversity, and the problem becoming the solution.