Rainwater harvesting at the GreenWood Forest Park

 the puzzle barn and the wisy filter
The Puzzle Barn the WISY filter and the
wooden box covering the two 2.5 m3 tanks

Greenwood Forest Park is an award winning attraction which was set up in 1993 by Stephen and Andrea Bristow and is located between Bangor and Caernafon in North Wales.  The Park is open to the public from early March till late October and has large numbers of visitors during the school holidays. The GreenWood Forest Park has a number of environmental educational displays, including the world's first environment friendly roller coaster.

In the Spring of 2007 Harvest  Your Rain was asked to design an install a water harvesting system to supply rainwater to the main toilet block using the large roof areas of the buildings within the Park. Reliability is a key concern as unflushed toilets can deter visitors. It is also important that any structures associated with rainwater harvesting are safe and either beyond reach of the public or robust enough cope with interference.

part of the Greenwood Forest Park map
Part of the GreenWood Forest Park Map

the WISY filter
The WISY diverter filter

The rain falling on the roofs of the Great Hall and the Puzzle Barn (total area 370 m2) is collected in the gutters and conveyed by 110 mm pipe hidden in overhead sluices, to a WISY  150 vortex filter. The WISY filter removes most of the dirt before the water is passed to two linked 2.5 m3 tanks which are hidden in a large wooden box on the island between the toilet block and the Puzzle Barn. These tanks are located about where it says Snowdon Snacks. 



Rainwater collected in the bottom tanks is pumped to a 5 m3 tank next to the toilet block. The upper tank supplies water to twin pumps which then pressurize the rain water supply to the toilet block. If the supply of rainwater to the bottom tank should run out, then the top tank will partially fill with mains water.  The system is expected on average to save 200 m3 water a year which is about 20% of the water used for toilet flushing in the main toilet block.

Percy and the Great Hall sluice
Percy the peacock outside
the Great Hall sluice
the Ggreat hall sluice
The Great Hall Sluice and downpipe