Development is essential – but its drivers and priorities are changing, says Fiona Atkins
Traditionally, environmental factors are only considered once an outline scheme design has been established. This means mitigation and compensation measures are identified and delivered through reactive decisions, rather than proactive drivers. This can make it hard to gain consent, and almost impossible to reach net-zero.
Across policy and in the infrastructure industry, we are seeing more demand for sustainability – and this is forcing change in the processes, designs and behaviours that once dominated engineering and construction. The draft Environment Bill outlines five environmental principles, one of which is “the principle of preventative action to avert environmental damage”. Ambitious aspirations around net zero, biodiversity net gain and social value drivers and indicators are being applied to industries, businesses and regions. The ability to meet these targets during project delivery is dependent on embedding processes at the earliest stages of a project, influencing the thinking and early decision making of clients, designers and contractors so that they deliver environmental-led design.
How could developing pre-mitigated design change the way we consider reasonable alternatives as part of the environmental impact assessment (EIA) process? And could a digital and data-driven approach enable that?
Environmental-led design
Environmental specialists typically refer to the mitigation hierarchy (Figure 1) when carrying out assessments.
Figure 1: The mitigation hierarchy.
However, we often only refer to it when design has been developed to the point where avoidance would require significant redesign work (and therefore increased cost and delay). This leads to a reactive iterative design process that can lead to confusion and inconsistency in the assessment and consenting phase – as illustrated in the left part of Figure 2.
Figure 2: Traditional design approach (left) vs environmental-led design approach (right).
We can challenge the traditional approach by exploring environment opportunities and mitigation earlier in the process, at the masterplanning and feasibility design stage, so that design teams are looking to avoid environmental impact from the outset. This approach is achieved by establishing a high-level environmental baseline as a minimum requirement and using this to inform desired outcomes as early as possible.
Using constraints (such as presence of ancient woodland) and opportunities (such as borrow pits being restored to wetland habitats) as objectives and sift criteria, we can inform option selection and thus minimise the reactive mitigation measures needed. If we identify the proximity and sensitivity (in other words, the value) of environmental features and receptors in the works area early, we can identify opportunities and challenges, pinpointing where sustainability gains can be had and finding solutions through the mitigation hierarchy.
Rather than being iterative and reactive, we can proactively and rapidly identify the most promising areas for environmental gains, and the worst risk areas in terms of compensation, programme constraints and reputation. With environmental considerations included from the start, we can inform the design process with environmental data. This will help improve the design’s sustainability, avoid costly rework and provide better evidence for EIA and consenting, making that process easier and faster.
A data-driven approach
By adopting the Common Data Environment (CDE) principles developed through building information modelling standards, coupled with cloud-based web-geographic information systems (GIS) technology to visualise and interrogate large datasets, we can automate the quantification and reporting of environmental assets. Trigger levels and thresholds (such as proximity, counts, areas and volumes, as defined in environmental topic and standard industry assessment guidelines) can then be used to assign a value or risk rating for each environmental feature or receptor. Clash tables can be automated from these environmental receptors to quantify environmental risk, and inform the design, cost modelling and programme.
This approach to managing data (spatial and non-spatial, environmental and design) can be applied, audited and interrogated throughout the project stages. For example:
- As more local and specific data is collected, clash tables can be rapidly rerun to identify trade-offs and challenge emerging design changes
- The early data-driven approach can better appraise, compare and evidence the environmental consideration of alternatives – a process that is too often retrospective
- As design develops, this baseline data can verify previous assumptions, and inform design development and construction methods, access and temporary control measures
- It can also assist in the consenting process, minimising the risk of delay and rework, because the data, design iterations and clash tables are archived. This means there is an auditable evidence trail of baseline information and decision criteria.
This approach gives visibility to real, tangible and specific impacts such as flood risk, habitat/species loss, and effects on residential receptors and air quality criteria. This can be used to inform location, site and design parameters. As such, we can better protect sensitive and valuable sites on an avoidance principle, and enhance value and access to areas and services from the beginning of development. We can also better identify ‘hotspot’ areas and receptors that need further assessment, and target mitigation measures.
Applying this approach throughout the project lifecycle can also improve communication with stakeholders. The visualisation features of cloud-based web-GIS enable better collaboration and information sharing, illustrating the design principles and mitigation strategies and providing evidence of feasible options and control measures. An informed design development process allows us to make intelligent adjustments, preventing wasted effort, unnecessary conflict and unforeseen difficulties. By improving the basis of design, the outcome of the entire project can be transformed for the better.
Case study
We applied this baselining approach to the route option comparison phase of East West Rail, where we won the ESRI Analytical Insights Award 2020. As can be seen in Figure 3, the route options were scattered with numerous environmental constraints that we sought to avoid. We:
- Developed project environmental objectives from a policy and legislative review and baseline conditions to inform option selection and design development
- Determined avoidance principles, a ‘red amber green’ risk scoring assessment and mitigation hierarchy
- Undertook a comparative assessment of a range of alternative options, using the above principles, criteria and hierarchy to determine a preferred option.
Figure 3: An example of key benefits and success factors.
This approach explored environmental opportunities before the route alignment was finalised so
that design choices could drive enhancement of the environment, rather than simply limiting impact through compensation and mitigation. The data-driven approach and cloud-based web-GIS technology was also championed as a collaboration platform that linked design, costing, client and consultation applications; the client has adopted and applied it going forward with the scheme. This led to the development of several pre-mitigated design solutions:
- We avoided the loss of ancient woodlands, local nature reserves, scheduled monuments and buildings
- 60% fewer Registered Parks and Gardens were affected
- 73% fewer Country Wildlife Sites were affected.
This project application has shown that by adopting this digital collaborative approach, the environment can be enhanced through design choice to avoid impacts and produce more defined mitigation requirements.
Consideration of alternatives
The EIA Regulations (SI 2017 No.571, para 18 (3) d, and Sched 4 (2)) require that the environmental statement includes “a description of the reasonable alternatives (for example in terms of development design, technology, location, size and scale) studied by the developer, which are relevant to the proposed project and its specific characteristics, and an indication of the main reasons for selecting the chosen option, including a comparison of the environmental effects.”
At the feasibility or optioneering stage of a scheme, design teams will look at the project requirements, such as alignments, timetabling, maintenance, system controls, form and strength, safety/emergency features – the list goes on, specific to sector, function, location etc. They use these as parameters to develop, test and sift emerging ideas until a single preferred solution emerges. By adopting a similar approach in environmental assessment, we can apply avoidance principles and mitigation hierarchy to embed environmental objectives in this sifting process, helping us make informed decisions to deliver a pre-mitigated design that improves the overall outcome.
Instead of a reactive and compensatory approach of comparing the environmental effects of developer controlled or specified design requirements, environmental features would be included as the main reasons or indicators for the selection, or parking, of a chosen option. As such, the ‘consideration of alternatives’ chapter in an environmental statement would list the environmental parameters and objectives and provide the quantified evidence from the data-driven baseline approach as a log of sifting decision criteria. The ‘description of development’ chapter would describe the pre-mitigated design, and topic chapters could focus on further mitigation and enhancement opportunities.
Using a digital data-driven approach can engage environmental considerations far earlier in the development process, as well as tracking evidence and quickly performing comparisons and sensitivity tests. It can also be available and updated throughout the lifecycle, which may optimise decision-making, improve communication and increase the agility of the design and consenting process for a project based on preventative action. Not only does the data-driven approach enable pre-mitigated design, it also embeds a quantitative evidence trail into a project from the start, which can be maintained and interrogated throughout the lifecycle:
- Assessment assumptions can be verified
- Site characteristics can be monitored and logged throughout construction and operation
- Mitigation requirements can be monitored, evaluated and amended as needed to achieve results.
As such, the environmental receptor model can inform design to minimise effects and improve enhancement measures, enabling the principle of preventative action to avert environmental damage.
Fiona Wilson is an associate director at Atkins.
