Ebsford were contacted mid-January to conduct a full site survey of this newly acquired site due for development having suspected Japanese knotweed could be present. At this time of year, the search was mainly focussed on looking for old dead canes of the plant relating to the previous season’s growth, crown material, summer foliage and any evidence that could mask the plants presence as is often the case.
Three stands of the invasive weed were found in the area of proposed car parking, spread from an adjacent property and beneath an access road in which services into the site would run. Google imaging allowed us to see that in 2003, significant disturbances had occurred on site when a large access route was made through a large stand of Japanese knotweed, which as a result is likely to have caused the other 2 stands to establish on site. One area had previously been herbicidally treated, however there was further evidence of dead crown up to one metre into site, meaning there was the potential that this surface was masking the full extent of the infestation.
As our client was under tight timescales to prepare the site for development, we recommended a mechanical system to remove all contaminated soils and provide a Japanese knotweed clear work area. Excavation and off-site disposal provides an immediate solution to remove all contaminated material from site with no ongoing concerns or management required, other than our routine site monitoring. Our team are experienced is in chasing out the rhizome so that the minimum volume is excavated, but ensuring all fragments are removed.
A scrape of the infested area was taken establishing the extent of the Japanese knotweed rhizomes. Excavations then commenced from the furthest identified rhizome, utilising a 20-ton excavator. Through chasing the extent of the root system, we endeavour to only remove the contaminated material rather than assuming large buffer zones. This was achieved by excavation was carried outng in 200mm layers with the sides and formation of each layer visually inspected by our site managerat each stage. This process was repeated until all contaminated material had been removed.
We supervised theSupervision of the removal from site ensures no spread whils the contaminated material being is loaded from the stockpile area onto wagons to be removed from site . The cContaminated material was thenis disposed of, in line with best practise, to a licensed facility that can accept Japanese knotweed material under the Ebsford Environmental Waste Carriers License.
As a further precaution A 100mm scrape was also taken from underneath the stockpile area to ensure no material was left in situ. As a further measure of biosecurity measure, the site manager carried out a final site walkover to ensure no areas had been missed was done. Upon completion theFollowing excavation works, root barrier membrane was installed to the site boundaries, as set out by the client. Site material was used to add a capping layer, ensuring the root barrier membrane is not damaged.
The project was fully completed in a matter of weeks and the site handed back to the client completely free of Japanese knotweed handed back to the client and ready for development works to commence.
