Ben Lindley, Company Director at Japanese Knotweed Ltd.
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PROJECT EXAMPLE: NAVIGATING THE CHALLENGES OF WORKING IN A PUBLIC SPACE
PRINCIPAL CONTRACTOR ROLE
Japanese Knotweed Ltd was appointed as the principal contractor to carry out full knotweed removal from the site. Our responsibilities included establishing a secure work area, setting up a works compound, and providing welfare facilities for our team throughout the duration of the project.
PUBLIC SAFETY
Being a ‘safety-first’ company means whole company commitment to safety at all times. We understand that what we do whether it’s herbicide spraying or using large pieces of equipment such as excavators can be a concern for the public.
This contract was no exception, as our team had to ensure zero risk to public safety whilst they were operating – and when they were not on site too. Cordoning the works areas off with fencing to create a bio-security zone was required to help prevent accidental disturbance and spread of the plants propagules.
These protective barriers were essential and one of the first tasks the team undertook, but it’s the on-going care and caution the team took throughout the contract that gave our client peace of mind there would be no complaints from the public or local residents.
THE SITE
The project site is a public park situated within a residential area, featuring both soft landscaped grounds and hard landscaped footpaths, with a brook running along one boundary. Our survey identified a mature knotweed infestation surrounded by dense vegetation including brambles, located beside the brook between two footpath bridges.
PROJECT CHALLENGES
Operating in a public space presented several logistical challenges:
- WORKING ALONGSIDE A WATERCOURSE: Our plan was to excavate a sump pool upstream of the knotweed to collect water which can then be pumped out and diverted around the excavation area and back into the brook further downstream.
- RESTRICTED ACCESS: Vehicle access for excavators and 8-wheeled muck-away lorries had to be organised via the main pathway, which required temporary closure to the public.
- STOCKPILE MANAGEMENT: A suitable area for stockpiling knotweed and contaminated soils was designated, though movement of waste across the site was limited due to space restrictions.
- DENSE VEGETATION: Access to the knotweed was hindered by thick vegetation, which was cleared using a flail and mulch system.
- TREE MANAGEMENT: Several trees with root zones within the excavation area were felled and stumps removed using a stump grinder to maintain biosecurity protocols. Additionally, Ash trees between the two bridges were completely removed.
- UNEXPECTED FINDINGS: During excavation, a clay pipe and manhole were discovered. Upon the client’s instruction, both were removed.
DELIVERY
As with all our contracts it started with an initial pre-start site management meeting that enabled full discussions of risk management and production of Risk Assessments and Method Statements for invasive weeds works to be undertaken. The team established and set out working areas to enable controlled plant and material movements.
BIOSECURITY MEASURES: Fencing off the works area created a biosecurity zone control around target invasive weeds, and protection from public access onto the works zone. A plant decontamination area allowed for a road sweeper with jet washer attachment to attend the site once each week to clean areas and plant.
Initial enabling works included vegetation clearance, a Watching Brief to tree removal works in bio-security areas to enable plant access and/or excavation works, and stream diversion.
To divert the stream we excavated a sump pool upstream of the knotweed to collect water which was then pumped out and diverted around the excavation area and back into the brook further downstream.
A SUCCESSFUL RESULT
All knotweed was excavated and stockpiled in a designated area for subsequent removal to landfill as controlled waste in accordance with Duty of Care Regulations. E.A. and using registered waste carriers for disposal at a specially licensed landfill facility. The site will be monitored for two years, with follow-up spray treatments applied to any regrowth as necessary.
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