Case Study - Hillhead Primary School, Glasgow

Works commenced in September 2009

Japanese Knotweed Solutions were appointed to undertake a full site survey
to assess the extent of the Japanese Knotweed infestation. Digital surveying
equipment was used to locate the areas of contamination and a full pack of
recommendations were produced for the Client. The results of this survey
work qualified that infestation was well established and amounting to
some 2,795 square metres.

The site was to be remediated for the development of Hillhead Primary School which was being moved from a nearby site. The existing site contained various small buildings and a car park away from the infestation which were demolished prior to works.  On inspection of the site drawings it was clear the majority of infestation was located in the footprint of the proposed building and due to the construction programme it was recommended that the contaminated material was removed off-site to licenced landfill and the remainder to be chemically treated. Our recommendations were followed and treatment commenced in September 2009 comprising of the following:

After initial spraying and injecting of herbicide into the root rhizome, JKSL then carried out removal of all rhizomes from the excavation areas, chasing the root structure until fully removed. The material was taken to licensed landfill following stringent methods to avoid any spreading of contaminated material across the site during excavation.

As a large portion of the root rhizome existed off-site and in view of persistence of the plant, a vertical root barrier was installed against the excavated faces preventing any re-growth from migrating back into the site. Where possible the barrier itself was impregnated with a residual herbicide to further reduce the chances of re-growth.

Finally, JKSL supervised the demolition contractor removing the retaining walls in order to prevent cross contamination from occurring and the Wildlife & Countryside Act (1981) from being compromised. All bricks were separated of rhizomes and stockpiled for disposal.

The whole process only took one week which then allowed the development to continue.  The new Hillhead Primary School opened in August 2011.