Practical Solutions to Soil Amelioration
Client / Site: Shanks Waste Management Ltd/Bunny Landfill
We were appointed by Shanks Waste Management Ltd in 2005 to design and supervise the restoration of an 11 hectare (ha) closed landfill site. The design needed to accord with the Local Authority’s objectives for a landscape fit and sustainable for end use and the client’s budget requirements for prompt establishment and early adoption.
The site holds a visually prominent location on an escarpment one mile from the neighbouring village. We agreed a design with Nottinghamshire County Council for 4ha of broadleaf woodland (oak, ash & field maple) over the inert outer walls of the cell and 7ha of agricultural grassland over the active, membrane-capped fill. New native hedgerows were planted alongside surface V-ditches for habitat linkage and landscape interface.
Shanks were producing clay loam soils from a screening operation on-site. For security of delivery, we recommended that soil testing and expert advice was sourced for their treatment and placement. A soils report confirmed pH 8.2 and identified a need for increased organic matter and nutrients to improve drainage and plant growth. We drew on existing industry contacts and introduced Envar to the site. They had links with suppliers of sewage sludge cake to provide a rich source of nitrogen and organic matter. Envar undertook supply, spreading and incorporation of 250 tonnes per hectare within just ten days, on a cost-neutral basis, and arranged all necessary Environment Agency permissions for the work.
Strong early establishment has been secured with oak reaching 4m and ash 6m+ in height. The agricultural grass sward is thriving and the site has achieved full aftercare sign off by Nottinghamshire County Council.
Forestry Commission grants are available for woodland creation work including that required as a condition of planning. Forestry Commission funding was therefore secured to cover 60% of planting costs. The ten-year Forestry Commission contract for good woodland establishment has also provided further assurance of delivery to the planning authorities.
Options for sheep grazing of the site are being explored with local farmers as a cost-neutral means of maintaining the sward going forward. The site has demonstrated the value of keeping an open mind to restoration. Odour issues can be associated with sewage sludge, but good communication with local residents and confining the operation to a short time window have allowed a productive and cost-effective use with the minimum of disturbance.
“Lockhart Garratt’s use of sludge cake as a cost free ameliorant and tight supervision of the aftercare have delivered effective restoration. Nottinghamshire County Council’s inspection in Year 2 placed the site among the best in the County.”
Digory Little – Formerly of Shanks Waste Management Ltd