Social Housing Project, Crumlin Road, Belfast

THE CHALLENGE

The site had an industrial past and was being redeveloped for social housing as part of the regeneration of the area. Within the site boundary were 5 distinct areas of Japanese Knotweed which had developed since the site became dormant. All but one of these was present within the build footprint for the townhouses. The timescale for completion precluded the potential for herbicide stem injection and works had already commenced  onsite when we were asked to manage the Knotweed.

 


 
THE SOLUTION

Based upon the timetable for the construction project, we determined that excavation and transfer of the plant and associated soils was the optimum solution. However, given the ability of the plant to rapidly colonise, containment and hygiene measures would be paramount. Working under the direct supervision of a Consultant Ecologist representing the client, we lined the loading area and periphery to each patch of Knotweed with polythene sheeting to prevent contamination of in-situ soils.

All surface and subsurface plant matter, together with proximal soils, was excavated and loaded into tipper lorries. Each load was covered with a heavy duty tarpaulin secured to the body and vehicle wheels were sprayed with herbicide prior to egress. The plant matter and contaminated soil was transferred to a specially commissioned landfill cell in England designed to meet the required containment measures for Knotweed in relation to depth from the ground surface and distance from the cell side wall liner. Our methodology rendered the site free from Knotweed within 3 weeks with no subsequent traces on the now complete site. The works were completed within budget to the satisfaction of the client and the regulator.