Grow 73 – Overtoun Community Garden, Overtoun Bowling Green, Rutherglen, South Lanarkshire by Gavin & Doherty Geosolutions
Shortlisted Brownfield Awards Category 3 – Best Public Engagement and Participation
Gavin & Doherty Geosolutions is proud to present this project for consideration for a Brownfield Award in Category 3 – Best Public Engagement and Participation.
Whilst Gavin & Doherty Geosolutions was the consultant on this project, we have been supported extensively by many organisations who wished to make this project successful. Namely:
South Lanarkshire Council (regulator)
Fife Council (provider of equipment & trained staff)
Scottish Contaminated Land Forum (event organiser)
Concept Life Sciences (laboratory)
Groundsure (data provider)
A&I Geotechnical (principal contractor)
Gavin & Doherty Geosolutions (consultant)
All parties worked together to enable the lodgement of a planning application, whilst mitigating the potential financial impacts of a full contaminated land investigation.
Rutherglen is one of six Royal Burghs in South Lanarkshire and has a strong industrial past, incorporating everything from coal mining to chemicals.
Rutherglen was once home to the Whites Chemical Works, with its history of chrome (COPR) disposal in disused clay pits, which has created a significant legacy for the district to manage. Grow 73, a community gardening group, was looking to lease three unused bowling greens in Overtoun Park to develop a community garden.
GDG was approached by Grow 73 to design an investigation, which would provide assurance that its new growing activities would be safe. Due to surrounding areas having pockets of known COPR waste, GDG had to determine if COPR or other unsuitable materials were buried at this site.
To fulfil likely planning conditions for the site, GDG was asked to complete a multi-phase investigation of the site, including:
Phase 1 Desk Study
Intrusive Site Investigation
Phase 2 Interpretative Report including risk assessment; and
Options to engage with key stakeholders to find ways of generating efficiency were discussed during early site visits and GDG began a process of connecting with regulators and potential contractors through the Scottish Contaminated Land Forum.
Without their support, this project may have been delayed or non-sustainable for Grow 73 to pursue. The principal participants in this submission are Grow 73, Scottish Contaminated Land Forum, South Lanarkshire and Fife Councils, A&I Geotechnical, and GDG who was ultimately responsible for scoping and reporting.
What did we do?
Contaminated Land Investigation is a complicated process. GDG proposed that, through SCLF, a training session be run at the site to provide young and upcoming practitioners experience and guidance from some more seasoned practitioners, in the field of contaminated land investigation.
During early discussions, Fife Council indicated that they maintained their own drilling rig and would be happy to support the effort by bringing the rig to the site and demonstrating the equipment whilst collecting samples.
A&I Geotechnical supported the process by providing technical advice and some insightful training during the day’s work, as well as putting together a Health and Safety Plan for the project. Between all stakeholders a viable investigation programme was set, that not only provided Grow 73 with what they needed, but gave an excellent opportunity for providing some insight into good practices in contaminated land investigations.
On the day
The objective of the works was to provide South Lanarkshire Council with sufficient information to approve planning for the change of use from a bowling green to community garden. However, the project also included the coordination of a group of young practitioners in the field of contaminated land assessment with training on areas including:
Sampling techniques and quality controls
Risk Management (Health and Safety)
Site investigation techniques
Investigation rationale development
Sample volumes and chain of custody
Attendees paid a nominal fee to SCLF as organiser, which was then donated to Grow73 to help fund the purchase of trees for the community garden.
Ross Cameron (A&I Geo) and John Cleland (GDG) explained why an investigation was needed, health & safety aspects and the schedule for the day’s work, before any holes were drilled.
Ross Cameron delivered a safety briefing to the attendees at the training session. This included a description of the use of cable avoidance tools and the hand auger sets.
John Cleland described sampling protocols and equipment cleaning to avoid cross contamination.
Making sure the correct sampling containers and labelling is followed on-site is crucial, therefore Chris Provan provided a session to the group following the first hole being opened.
Fife Council was able to provide the use of its hydraulic percussion drilling rig. The Council’s team ran the drilling rig and, as a group, all attendees were able to watch the process, collect samples and ask questions of the crew.
In addition to the drilling rig, Fife Council provided the use of a Cable Avoidance Tool, three Hand Auger Sets and a Tablet Logging Device. The bores were logged in AGS format and the attendees were given instruction on how to log a borehole, in accordance to British Standards.
Altogether 40 people benefitted from the training day, including students from the University of Strathclyde, representatives from Scottish Environment Protection Agency and staff from several environmental consultancies, contractors (both investigation and remediation) and local authorities, including South Lanarkshire, Fife and Glasgow City Councils. Also, people who were demonstrating one function were able to learn best practice from staff experienced in other skills and disciplines.
The composition of the bowling greens was as expected: an imported ash drainage layer had been used to level the site prior to placement of topsoil and turf. The underlying natural material was a boulder clay, with silty lenses and gravel. The principal material of concern was the ash, but samples were collected from both made ground and natural materials to confirm the absence of any impact by contaminants on underlying materials
Elevated metals and PAH concentrations were recorded in the ash samples analysed, in excess of the relevant screening values for allotments; however, no concentrations exceeded screening values for public open spaces (parks) and no elevated concentrations were recorded in the underlying natural ground.
Waste Classification evaluation indicated that, whilst the material was not a significant risk to the wider environment, soil disposal at non-hazardous landfills may not be possible due to a generally low pH and elevated total organic content.
Leachability results, obtained as part of Waste Acceptance Criteria testing, did not indicate that contaminants of concern were particularly mobile, and it was concluded that the risk to the water environment was low, enhanced by the presence of boulder clay beneath the site.
The assessment concluded that the site represented a low risk to the proposed development or wider environment, on the basis that the following recommendations were incorporated into the development plan.
Raised Beds: All raised beds should allow for at least 500mm of clean soil to be placed above a root barrier/geotextile membrane. This will provide a suitable isolation depth of at least 600mm (including the current topsoil layer on-site) to mitigate risk to produce.
Excavated Tree Planting Beds: A tree planting scheme should allow specific areas to be excavated out and lined with a suitable root barrier geotextile and each tree planted in clean imported soils, to ensure the trees will have sufficient space for roots to develop.
Options for Ash Management: As the contaminants of concern are restricted to the ash layer across the site, it was recommended that an ash management plan be included in the development plan for the site.
The ash does not present a significant risk to human health or the environment in land uses other than as an allotment. The recommended mitigation of risk is the installation of a root barrier and raised beds. During construction, contact with ash should also be minimised, by using gloves and providing hygiene facilities throughout the works.
Thanks to the combined efforts of diverse participants (early-career and experienced, regulatory and commercial, paying, voluntary and paid) it was demonstrated that the site was suitable to be brought back into beneficial use as a community garden. Cross-sector engagement and participation facilitated the ground investigation and provided hands-on training at a fraction of normal cost to all.