Q&A with Duncan Cartwright, Atkins

Ahead of this year’s Brownfield Land Scotland 2020 conference, which is taking place on 5 February in Edinburgh, we caught up with Duncan Cartwright, Associate Director, Atkins, who gave us his insights into groundwater risk assessment strategy.

Q. Could you outline situations where a risk assessment leads to unnecessary remediation?  A. One of the biggest challenges of water environment risk assessment is deriving robust regulatory compliant criteria that can be effectively utilised within the remediation strategy for a site.  

I have heard of instances where risk assessment criteria have driven unnecessary remediation.  However, these occurrences have not necessarily been due to inadequate development of the risk assessment, but inappropriate use of the criteria within the wider strategy.  

Risk assessment numbers are to be used as a line of evidence to support the decision-making process and must always be considered in the context of the wider objectives and what constitutes reasonable endeavours.  That said, there are plenty opportunities to refine water environment risk assessments that can significantly reduce conservatism and reduce the need to start entering into cost-benefit discussions.

Q. Is this the fault of guidance and or legislation and do you think they need changing? A. I think that the legislation and guidance in Scotland currently strikes the right balance in enabling development of brownfield sites, while ensuring adequate protection of the environment.  The technical guidance is clear and there is sufficient flexibility to enable multiple lines of evidence to be drawn together to develop sensible remediation strategies. I always advocate an approach of early and transparent engagement with the regulators, such that investigation and assessment design can be tailored to meet the specific needs of the site and regulators.

Q. How different is the situation between Scotland and the rest of the UK? A. Given that the legislation across the entire UK is (currently) underpinned by the Water Framework Directive, we are all working to the same objectives.  Even so there are some significant differences in the process of brownfield risk assessment, driven by differences in policy, legislation and regulatory roles.  It is therefore imperative that the country-specific approach and terminology (which often has a legal basis) is followed.  Having the clear understanding of the prevailing legislation and guidance is crucial for gaining the efficient discharge of planning conditions etc. 

The technical aspects of the risk assessment process are common across the UK, however, and when it comes to the more detailed assessments, the guidance and tools are the same. Ultimately, the standard of remediation is the same across the UK.

Q. Which information requirements are the most frequently not met? A. From a water environment perspective, data is king in reducing uncertainty.  So often risk assessments are constrained to a highly conservative basis, due to the absence of data that would support techniques to demonstrate attenuation.  These information sources include improved monitoring well network, to cover down gradient of the source area (not always achievable), scheduling optimised soils and groundwater analysis suites (e.g. natural attenuation parameters – and then actually analysing them!), and in-situ testing.  

Some of the information requirements can be included at the initial investigation stage, without disproportionate cost, others will need to wait until later iterations and will be driven by the initial findings.  More novel, and costly, techniques may be utilised during the regulatory negotiation process to support agreement of appropriate and sustainable remediation strategies (techniques such as microbial DNA assay analysis to support evidence of natural attenuation in the aquifer system).

Q. Could you outline the key factors in moving from a risk-based to a cost-benefit approach and what new information is required? A. As eluded to above, it is often a challenge to derive risk-based quantitative remediation criteria that are compatible with achievable and sustainable remediation strategies.  A formal cost-benefit assessment, completed strictly in accordance with the guidance, is a significant piece of work – an assessment rarely undertaken in my experience, particularly for the smaller developments.  There is, however, normally common ground to be found between site owners/developers and regulators that consider all the lines of evidence to enable appropriate remediation strategies to be developed, while remaining true to the ‘as far as reasonably practicable’ position enshrined in the guidance.

Q. Could you outline some advances in data collection and modelling which have changed decision making? A. I think the opportunities currently lie in improvements in remote monitoring and these will improve further with the planned 5G networks and improved down-hole hardware.  

There have been some great advances in real-time gas monitoring equipment and remote LNAPL monitoring in groundwater wells. Both these parameters benefit strongly from having continuous monitoring rather than traditional spot monitoring events. The challenge is making them commercially viable in a very strongly competitive market place.  However, case studies are building up and their true value is becoming better appreciated.  I believe that these new techniques will become utilised more and more, particularly when they provide compelling evidence to enable regulators to ‘sign-off’ a remediation or development.

Want to know more? Join us at our upcoming Brownfield Land Scotland 2020 conference on 5 February in Edinburgh where Duncan will be going into further detail on groundwater risk assessment in his presentation 'Developing a Pragmatic and Appropriate Groundwater Risk Assessment Strategy that Meets Regulatory Requirements and Avoids Unnecessary Remediation'.

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