Maintenance and Resilience of Green Infrastructure
On Thursday 23rd May 2024, Heriot-Watt University and the Royal Botanic Garden Edinburgh ran a workshop focusing on the maintenance and upkeep of green infrastructure (funded by the RECLAIM Network). The overarching aim of the workshop was to encourage thinking and facilitate discussion on the critical aspect of maintenance within green infrastructure.
55 delegates braved the rather apt rainy conditions in Edinburgh (a total of 52.6 mm rainfall recorded on site that day despite a dry run up to the workshop; see Figure 1), ready for a day full of discussions on the performance of green infrastructure to manage flood risk and offer multiple co-benefits.
Figure 1: Daily rainfall in the lead up and after the workshop. The day of the workshop is shown in red.
Introduction, icebreaker and thematic analysis
The day started at the Caledonian Hall within the Royal Botanic Garden Edinburgh (RBGE) with informal conversation over breakfast whilst delegates collected their name badges and made introductions. Dr. Daniel Green (Assistant Professor in Nature-based Solutions at Heriot-Watt University) kicked off by introducing the goals of the workshop the wider RECLAIM network, followed by an online presentation from Prof. Prashant Kumar, PI and Director of the RECLAIM programme. Daniel, Dr. Emma Bush and Caitlyn Johnstone (Nature-based Solutions Scientists at RBGE) then proceeded with interactive table-based ice-breaker activities to establish delegate backgrounds (see Figure 2a). The interactive questions revealed an almost perfectly balanced 4-way split between job sector categories (see Figure 2a); the workshop planning was successful in drawing a diverse mix of attendees and priorities. The varied perspectives and sectors were evenly split amongst the tables, creating an environment that invited lively and balanced discussion in the roleplay exercises planned for later in the day.
The second part of the session centred around two key questions: (1) “How are you involved in green infrastructure and SuDS?” (results shown in Figure 2b), and (2) “What does maintenance [in the context of green infrastructure] mean to you?”. Results were hidden from participants until after lunch, where participants would reflect and vote on the best response to this question. Voting pathways for the first set of questions are visualised in Figure 3.
Figure 2: Delegate responses to the questions (a) “What category best describes your job sector?”, and (b) “How are you involved in green infrastructure and SuDS?”. *Please note, the Other section in Figure 2a was largely made up of attendees within charitable organisations or members of the local community with an interest in green space who saw the event advertised via EventBrite.
Figure 3: Workshop attendee’s job roles, sectors and responsibilities. Figure 3 summarises delegate roles, sectors and key responsibilities.
All participants provided free-form, extended answers to the question “What does maintenance in the context of GI mean to you?”. 18 of those responses received upvotes from other attendees. From these 18 agreed definitions, six main themes emerged. The themes that arose from the attendee responses and subsequent discussion (see Figure 4) formed the latter part of our afternoon session. Functionality and Performance was consistently identified as an important consideration for maintenance, with delegates defining maintenance as “Maintaining the functionality of BGI” (7 votes), “Ensuring functionality of intended features” (6 votes), “Boosting multifunctional performance” (7 votes) and “Long-term performance against design specifications” (5 votes). The theme Lifecycle and Long-term Perspective was also seen as an important theme by all. Maintenance should “Focus on the whole life of an asset” (6 votes), involve “Long-term planning” (3 votes) and be “Integrat[ed] into project planning” (4 votes) from the start to ensure that GI performance is maintained long after installation. At the heart of this is Funding and Resources, which should be considered to ensure that there is capacity and skill to maintain assets across the lifecycle of GI. Other key themes identified were Shared Responsibility and Integration [“Shared stewardship” (5 votes) and “Community engagement“ (4 votes)] and the promotion of other co-benefits of GI through offering Biodiversity and Ecosystem Services and Adaptability to Climate Change. The afternoon dialogues, discussed later, reinforced and fleshed out these themes further.
Figure 4: Preliminary thematic analysis map of voted upon responses to the question: “What does maintenance [in the context of green infrastructure] mean to you?”.
Tour of the Royal Botanic Garden Edinburgh’s Nature-based Solutions sites
Umbrella in hand, the workshop broke off into 4 groups (~16 in each) and headed out to see of the Nature-based Solutions features across the Gardens, shown in Figure 5.
Figure 5: NbS tour route around RBGE.
The first stop on the tour was a small toilet block building featuring downpipes fitted with stormwater planters. The planters collect roof runoff from the toilet block and attenuate flows through the rain garden plant species and engineered soil media, before entering a piped outflow. The stormwater planter acts as a source-level (and low cost) control measure which can be easily implemented by homeowners and businesses alike, whilst offering additional, hidden benefits to people and properties. One newly commissioned stormwater planter gifted to the Botanic Gardens by Brian D’Arcy, and two NatureScot planters commissioned as part of COP26, make up this NbS tour stop. All three planters were instrumented by the Nature-based Solutions and Grounds Teams at RBGE and Heriot-Watt University dissertation student Elise Cheng.
Next, groups stopped off at the lake, which offers a large water storage potential in the highest flood risk area of the Botanics. The lake is a beauty spot that offers public amenity value, whilst providing a habitat for Kingfishers and other bird species. Afterwards, groups headed to see the fallen tree. The fallen tree prompted discussion the fact that we should recognise plant dieback and failure within systems that work alongside natural processes:
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We can’t just pick the “good” natural processes that we want to work with in green infrastructure and need to appreciate the dynamic and changing nature of systems. Flood provision, pollution control and natural amenity value are all well and good, but we need to understand that we are working with unruly natural processes which can’t, and wont, always be pruned, perfectly maintained systems.
” Summary from Group 1’s discussions on fallen down tree and surrounding fallow land.
Next on the tour was the John Hope Gateway to view the green roof from an afar vantage point. The green roof is relatively low maintenance, has been operational for over 20 years and is composed of Sedum species and cultivars. The biodiversity mix changes with the weather, but is predominantly made up of Sedum lydium, and a selection of weed species that have colonised the roof, including Senecio vulgaris, Poa annua and Sonchus apser. The key issue with the green roof is that of ownership, sitting between estates/infrastructure teams and horticultural teams, highlighting issues of responsibility and ownership. However, this ‘messy middle’ is on RBGE’s radar and will be addressed in new plans for green roof design and maintenance.
And finally, we stopped off at the RBGE rain garden: RBGE’s flagship NbS feature. The rain garden is currently being monitored by Heriot-Watt University PhD student Aravindan Kalaichelvam, who is collecting data to inform performance of green infrastructure systems. The rain garden features an array of hidden sensors measuring the performance of rain gardens to protect us against floods and droughts and has been subjected to regular seasonal testing to characterise its hydrological and water quality performance. The rain garden was commissioned in 2017 to prevent regularly occurring flooding of the surrounding footpaths which were causing widespread disruptions to visitors and groundskeeping staff. Amazingly, and on a day where we were focusing on failures and maintenance of green infrastructure, the rain garden is a story of success: since its commissioning, there has been no localised flooding on the footpaths and the rain garden has been self-sustaining and maintenance free. Raoul Curtis-Machin, Director of Horticulture and Visitor Experience at RBGE, later confirmed that the rain garden was still holding up strongly after the non-stop rainfall on the day of the workshop.
Figure 6: (a) Daniel discussing plant evapotranspiration dynamics in a rather soggy (but functioning) rain garden; (b) The “1 million visitors to RBGE each year” statistic doesn’t include these beaked tag-alongs but the photograph does highlight the multi-benefits of green infrastructure beyond flood control.
Photo credits: Sophie Cox and Murray Coburn
After the tour and discussions, it was time to dry off before lunch was served!
Discussions and synthesis
The afternoon session kicked off with an interactive discussion and synthesis activity focusing on green infrastructure and SuDS design. Part 1: ‘The Perfect GI Design’, started the session off with a hands-on activity where we asked delegates to design their perfect GI scheme (if no barriers to implementation were present): “Whether you are considering a single rain garden or a catchment-level connected forest and stream, what does the perfect Nature-based Solution scheme look like for your area?” (See Figure 7).
Figure 7: (a) and (b): A collaborative, creative approach to urban planning and design; (c) and (d): True multifunctionality: prize winners ‘Table 2’ even dissected horticultural table piece displays to add value and additional co-benefits to the resources on hand.
Photo credits: Sophie Cox and Louise King
Using Play-Doh, Lego and other resources, this session led to several groups creating fascinating, imaginative and thought provoking works of art, detailing key aspects of their idealised SuDS scheme should look like. This activity provoked some rich discussion and thought from different perspectives and backgrounds, where each of the groups considered who was involved in their scheme at different stages, what the features helped to improve, and how the features might change and adapt with the community through the years (see Figures 7 and 8). This provided the basis of Part 2 of the afternoon, where a facilitated discussion on maintenance, warning signs, sources of knowledge and successes/failures within the UK context were the focus (see Figure 8).
Figure 8: Emma and Caitlyn summarising group discussions and take-home messages from the afternoon synthesis.
Photo credits: Louise King
The word clouds shown in Figure 9 summarise and collate the responses to the questions focusing on what we do well in the UK (Figure 9a) and areas where we need to improve (Figure 9b) when considering green infrastructure and SuDS. These link clearly with our preliminary thematic analyses, presented earlier.
What do we do well? What do we need to improve?
Figure 9: Word cloud responses to (a) What do we do well at in the UK when it comes to green infrastructure, and (b) What areas do we need to improve on when it comes to GI in the UK?
The main take home message from this section of the workshop was that collaboration is key to overcome the main challenges that face widespread NbS implementation. All groups recognised that we have a lot of work ahead to ensure that these barriers are overcome, but we will benefit from a collaborative approach featuring insight from a range of stakeholders. One issue that was raised in this section was the issue of maintenance and litter within SuDS. Here, visibility of ‘failures’ or lack of maintenance and responsibility appears to be the issue. The consensus was that communities and practitioners don’t want to see visible problems on the surface (i.e. vegetation dieback, litter accumulation, standing water, etc.). This triggers a negative response when there are visible and unsightly ‘signs of failure’. However, should we see this as an opportunity for us to fix and rectify the issue, rather than the issue being hidden and only visible when the system fails to perform correctly during a rainfall event, like in grey infrastructure systems? Green infrastructure involves a shift in attitudes and perspectives to one of acceptance: systems don’t always need to be pristine and immaculate. However, there is a fine balance between maintaining functionality and aesthetic.
Additionally, we all recognise that maintenance is a key aspect when it comes to ensuring long-term success of green infrastructure (Y-axis of Figure 10), but often, maintenance is neglected from practitioner’s workloads (X-axis of Figure 10). Whether this is due to policy frameworks or lack of funding is unclear, but there is a distinct lack of maintenance considerations at multiple levels which needs to be addressed. Ownership and collaboration of green infrastructure (and maintenance) is not currently supported within current funding and resource models, which often only support green infrastructure design and implementation. Maintenance needs to be at the forefront of schemes to ensure longevity and success. Additionally, we need to identify who will be responsible for maintaining green infrastructure, and question whether the public want to and can be involved within this process (and if so, at what stages) so we can achieve the Perfect GI schemes, outlined in Part 1 of the session.
Figure 10: Ranked responses to the questions ‘Maintenance is fundamental to the success of GI’ versus ‘Maintenance is a key aspect of my work’. 100 refers to full agreement with the statement, 0 refers to no agreement.
Wrap up, outcomes and next steps
Lastly, the event concluded with a drinks reception, linked to the newly launched RBGE ‘Plants with Purpose’ programme (see Figure 11). The first PhD student from this programme, focusing on flood risk and functional plant traits, will start in September 2024 and build upon some of the key points raised within this lively and active RECLAIM workshop.
Figure 11: (a) Raoul Curtis-Machin wrapping up the RECLAIM event; (b) stream table micro-catchment to visualise key hydrological processes just before the drinks reception kicked off.
The workshop prompted a comprehensive thematic analysis of maintenance considerations for green infrastructure, highlighting key areas such as functionality, lifecycle planning, funding, shared responsibility and adaptability to climate change. This helped us to identify research gaps and priorities for future studies on green infrastructure maintenance and performance from a range of stakeholder groups. The next step is to put the full workshop results and outcomes into a short, published commentary piece, which Daniel, Caitlyn and Emma are planning to finish up this summer during Daniel’s RECLAIM-funded secondment at RBGE.
Additionally, the workshop promoted cross-sector networking, knowledge exchange and discussion between predominantly Scottish academics, practitioners, policymakers and community members, helping to foster future collaborations. The RECLAIM workshop was promoted through the Scottish Green Infrastructure Forum, and it is hoped that we can build upon the success of this workshop and organise regular (1 – 2 year) events to maintain dialogue and share key updates and best practices. Further, the workshop provided practical and actionable insights into the real-world challenges and successes of maintaining green infrastructure, exemplified by the SuDS features across the RBGE, prompting creative design concepts for ideal green infrastructure schemes.
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The RECLAIM workshop fostered the perfect environment for positive and constructive discussion about the SuDS lifecycle and how we can better manage this as a community going forward. It brought together passionate people from a diverse range of organisations who each provided their own unique and insightful perspectives. Collaboration, stakeholder engagement and finance were key themes which arose from talks throughout the day – however the highlight of the day was definitely getting a practical demonstration of the green infrastructure constructed around the Botanics, courtesy of mother nature herself.
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Murray Coburn, AECOM
Maintenance, interestingly, seems to be often outsourced to the public, so we hope that this is changed going forward. Maintenance needs to be incorporated into the design, planning and implementation of schemes to ensure that we are sustaining long-term functionality of our urban green infrastructure.
Funding and acknowledgements
This workshop has been supported by the UKRI-funded RECLAIM Network Plus grant (EP/W034034/1).
The workshop was planned, executed and delivered by Dr. Daniel Green, Assistant Professor in Nature-based Solutions at Heriot-Watt University, Caitlyn Johnstone, Nature-based Solutions Scientist at the Royal Botanic Garden Edinburgh, and Dr. Emma Bush, Nature-based Solutions Scientist at the Royal Botanic Garden Edinburgh.