Developing restoration guidance for landfill sites

 

Scope of the problem

There are an estimated 4200 landfill sites currently operating in the UK. This represents a large land area and one which has been examined critically over more than ten years by Forest Research for its ability to support woody vegetation as part of a sustainable reclamation solution.

Restoration practice for landfills has, until comparatively recently, been of poor quality, and after landfilling, many sites were simply covered by a layer of spoil or soil, often of inadequate thickness to sustain plant and tree growth. In addition, landfill gases had a tendency to penetrate into the root zone, and cause further death.

In more recent times, modern landfills have been constructed as a series of cells, the floor, walls and capping layers formed from relatively impermeable geological and synthetic materials, in order to prevent leachate from within the landfill percolating into underlying rock layers and eventually into ground and surface waters. The landfill cap has until recently, been formed of compacted clay, and has been covered by up to one metre of soil or soil-forming material in which to establish vegetation.

Research overview

Forest Research have studied how early and modern landfill restoration practice meets the needs of vegetation to be established on landfills as part of normal reclamation legislative requirements. 

We have been commissioned by the Department for Communities and Local Government (DCLG) - formerly Office of the Deputy Prime Minister (ODPM) - to produce authoritative guidance on the reclamation of landfills for woodland establishment.

This research began in 1992 and is ongoing. 

Publications

Final contract report to the Department for Communities and Local Government detailing research over a ten year period to examine tree growth on modern containment landfill sites:

• Woodland establishment on landfill sites:  Ten years of research

Several interim reports are available:

• Woodland establishment on landfill sites: site monitoring. (2000) - from DCLG.
• Tree establishment on landfill sites (Research and updated guidance 1997) - from Forestry Commission.
• The potential for woodland establishment on landfill sites (1992) - The Stationery Office.