A project by Guinness UDV Park Royal Brewery acting as representatives for Diageo and Brent Business for the Environment Ltd, as part of the Diageo sponsored Water of Life project.
The Welsh Harp Reservoir is a Site of Special Scientific Interest and is famous primarily for breeding wetland birds, with significant numbers of nesting Great Crested Grebe (more details on the Welsh Harp Reservoir page). The diversity of the waterfowl and the variety of plants growing along the water are also of special note for London (see also Wild Life page).
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On the south eastern side of the Welsh Harp Reservoir there is a wetlands area between the Reservoir and the North Circular Road (A406). The wetlands include some woodland, marsh and grass areas. Two streams feed the wetlands. They receive surface water runoff from the North Circular Road and the neighbouring urban streets. |
 Click here to see the map |
Samples of water taken from these streams on 20th March 2001 show, that although the flow appears visually clean, there is evidence of pollution caused by domestic effluents and chemicals found in detergents. Click here to see some of the results.
Some areas of the site near the Reservoir bank are affected by pollution originating from the two streams with elevated levels of such chemicals, as cadmium, copper, lead and zinc. Click here to see some of the results.
The Environmental Agency classifies the water quality of the two rivers upstream of the Welsh Harp Reservoir, and the River Brent just downstream as Grade E, 'Poor'. No chemical or biological sampling has been undertaken in the Welsh Harp Reservoir. Therefore, any improvements made to contributing discharges into the Reservoir will help to improve water quality overall.
The development of a Reed Bed at the Welsh Harp Reservoir conforms to Environmental Strategy for the Millennium and Beyond, an official document by the Environmental Agency, and its North London Local Environmental Agency Plan (LEAP) which consist of an agenda of integrated action for environmental improvement. Among the issues covered in these documents are low flows, enhancing biodiversity, improving fisheries and addressing pollution.
A feasibility study was carried out by Halcrow (Technical Reason for the Task. Welsh Harp Reservoir Reed Bed Feasibility Study, May 2001). The researchers looked into the pollution sources and its prevention systems of the two streams, the current water and soil quality, the wildlife and all aspects associated with constructing a new reed bed in this area, including the long term management of the project.
The Feasibility Study concluded that the main benefits of introducing a reed bed here will be:
A reed bed is a shallow water-logged area planted with the Common Reed (Phragmites australis) retained within a waterproof material to prevent the waste from leaking out of the system. This plant has a unique property which makes it an effective natural waste water treatment system: it can transfer oxygen from its leaves to its root system (rhyzosphere), where it is released. The oxygen becomes food for micro-organisms and bacteria which break up the pollutants in the water. Thus, travelling slowly through the maze of reed roots, the waste is cleaned up by biological action and the water leaves the reed bed completely safe for the environment.
Reed beds are widely used in the UK for the treatment of all kinds of industrial and domestic waste and monitored by the Environment Agency. This is a traditional form of water treatment, withy (willow) beds were used in Victorian times for the same purpose.
| by May 2001 | Initial research and preparation of documents. Technical Reason for the Task. Welsh Harp Reservoir Reed Bed Feasibility Study prepared by Halcrow. |
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by mid March 2002 |
Access board walk and viewing station on the Welsh Harp Reservoir repaired. The reed bed area dug up and prepared for planting |
| by May 2002 | The construction of a viewing platform for reed bed. The planting of reeds. |
| by June 2002 | The completion of the reed bed. |
