Giant leaf shaped rainwater collector built using recycled wood.

Edit Hook

In the South of England summer rainfall is often intermittent. However vegetables need constant watering to grow optimally. The solution is to capture rain when it falls and store it until it is needed. The “Elf Shelter” is an effective sustainable design of water collector to accomplish this. It consists of a 5 x 3 metre leaf made of recycled wood, the details of which are described below. The giant leaf is an accurate scaled up copy of the leaf of a typical local deciduous tree–see photo in Gallery.It’s called the “Elf Shelter” because its secondary purpose is to encourage mythical elves to return; elves like to sit under leaves when it is raining.

Key Differentiators

The design is both very effective at capturing rainwater and uses 100% sustainable and recycled materials. The wood used: coppiced hazel logs for the uprights, second-hand 5-inch thick building plywood for the beams, the tops of old school desks for the centre of the leaf, and pieces of old polling booths for stem, ribs, and edges of the leaf. The central water channel is recycled plastic guttering.

Biomimicry Story

The vegetable garden that required watering is located on the Weald, an area of afforested hills in Southern England. ‘Weald’ is derived from the German ‘wald’, meaning forest. The native woodland consists of deciduous trees such as oak, beech, ash and birch. These trees grow leaves in the spring for the period of maximum insolation, then discard them before the darkness of winter, when the tree is dormant and conserving energy. The trees adopt a strategy to maximise the photosynthetic return on investment in leaf production which offers a relatively quick return on investment. The design of the Elf Shelter follows this lead, maximising the rainwater harvesting return on investment by having a giant leaf made 100% out of sustainable and recycled materials. Although the surface of a deciduous leaf is relatively flat, other types of plant use their surface areas to capture water. Making the top surface of the Elf Shelter leaf dip towards the central groove, and the central groove dip towards the water butt, ensures that the rainfall flows from the point of impact on the leaf to the point of collection.

Challenges Solved

How to make a rainwater collector that maximised the ratio between the volume of rainwater collected and the environmental impact of construction materials used.

Edit Summary