Assessing Sensitivity, Capacity and Opportunity in the Wider Historic Environment
Can the historic landscape be more fully involved at the earliest stages of planning for large-scale landscape change?
Approaches to change
The European Landscape Convention requires ratifying governments, like the UK’s, to care for the whole landscape, including the everyday and degraded.
How can the whole historic landscape be more fully involved at the initial and strategic scoping stages of assessing sensitivity to and capacity for large-scale change involving, for example, major industrial development, infrastructure projects (transport, energy, water, etc) and extensive house building?
The historic landscape also has a significant role to play in urgently responding to the climate and biodiversity crises.
This was stated succinctly by Historic England’s Chief Executive, Duncan Wilson, who said that ‘the scale of the climate change challenge can feel overwhelming, but our heritage is part of the solution, and will inspire practical solutions for a more sustainable way of life, today and tomorrow’ (Our Climate Change Strategy, March 2022).
Many responses to change will be at the heritage asset level. Those who care for monuments, buildings and conservation areas have long drawn on investigation and selection when negotiating change: investigation improves understanding of the development, character and significance of places and features, and selection supports protection and involvement in the detail of decision-making. Responses to the climate change challenge will, however, involve much larger areas and new types of change, including rewilding and various forms of flood alleviation; new vulnerabilities and sensitivities; and, most significantly, new opportunities.
Historic England commissioned a review (Herring, 2022) of how Historic Landscape Characterisation (HLC) has been used when assessing the sensitivity of different types of place to the effects of particular forms of change.
All approaches to assessment recognise that there is no inherent sensitivity of a place, or type of place, to all change scenarios because the effects of each act differently on character, distinctiveness, patterns and fabric.
For example, a medieval field pattern will have different sensitivities to rewilding, installing solar farms, or laying out new roads. Sensitivity assessments therefore concentrate on establishing degrees of vulnerability, and capability , in relation to each form of change.
Historic England supported development of Historic Landscape Characterisation, which describes the whole historic landscape, because it could be used, amongst other applications, as a spatial framework for such strategic assessments. Historic Landscape Characterisation Types are identified through attributes like historically-derived morphology, pattern, age and condition, all relevant when considering the effects of change.
A consolidated approach to sensitivity assessment that will form the basis of forthcoming Historic England guidance involves four stages:
- Explore the change scenario, especially its likely effects on fabric and character.
- Consider the vulnerability of each type of place (eg Historic Landscape Characterisation Type) to those effects, or its capability of being positively affected by the proposed change.
- Assess how the attributes of the HLC Type that contribute to its significance are affected by the effects of the particular form of change.
- Drawing together the above, present recommendations that guide decisions and action.
Historic England and the Environment Agency have recently explored how sensitivity assessment may be adjusted to also support ‘opportunity modelling’. This can involve scenarios that address climate change and facilitate environmental growth and carbon sequestration, encourage nature recovery, manage riverine and coastal flooding, or support other initiatives for which there is substantial public support (Herring and Turner et al 2022).
Opportunity modelling would inform the work of a broad range of land managers and decision-makers including agencies like Natural England and the Forestry Commission. It might include woodland creation, biodiversity enrichment and more sustainable land and sea use, including agriculture and fishing. It can be linked to and inspired by historical practices, as recorded in Historic Landscape Characterisation and Historic Seascape Characterisation, which may be drawn upon when considering national, regional and local strategies, policies and actions.
Opportunity modelling would still consider vulnerabilities to ensure disturbance and damage is minimised, but its emphasis would be on identifying Historic Landscape Characterisation Types capable of accommodating desired types of change by recognising their ‘affordances’: the qualities and attributes that can facilitate wished-for forms of change.
Affordances may be drawn out by exploration of the requirements of change scenarios and the attributes of Historic Landscape Characterisation Types. For example, when managing excess water in times of flood, relevant affordances can be expected to include the likelihood of there being existing channels or hollows that can be used to either divert or temporarily store the water.
An approach to opportunity modelling was developed through consideration of the effects and requirements of eleven change scenarios, including eight options presented in the Environment Agency’s Thames Valley Flood Scheme and three environmental growth scenarios.
Opportunity modelling has just three stages, not four:
- Explore scenario: requirements and predictable effects.
- Assess vulnerabilities of Historic Landscape Characterisation Types to those effects, and the affordances of each Historic Landscape Characterisation Type in relation to requirements.
- Score and qualify opportunity potential and then present on GIS based mapping, with an accompanying narrative.
Consideration of significance (sensitivity assessment’s third stage) as a separate stage was dropped to reduce double-counting: assessment of vulnerabilities and affordances both subsume consideration of the effects of the change scenario on those attributes that contribute to significance. This is also consistent with the insistence that places do not have inherent sensitivity or capacity to all forms of change, and it allows the significance of heritage assets and local places to be called upon later in decision-making, in any formal planning process or when prioritising funding.
The opportunity approach can be illustrated through two scenarios. ‘Offline Flood Storage’ involves temporary diversion of flood water into a storage area to be released back to the river after the flood.
Its reduction of a flood’s destructive power benefits communities, riverside heritage assets and natural environment. Effects and requirements vary depending on the extent to which the water storage area and river-side sluices simply reuse existing features and earthworks.
Woodland planting, a form of rewilding that also addresses flooding, biodiversity and carbon capture, usually transforms character, visibility and biodiversity of green or brown field land. Assessment involves assessing whether ground preparation would affect archaeological remains and whether vegetation changes can be expected to result in gains rather than losses of biodiversity or landscape character.
For each of the numerous Historic Landscape Characterisation Types expected to be affected by the scenarios, professional judgement is used to give positive and negative scores for both vulnerabilities and opportunities in relation to variables like historic character, time-depth legibility, historical land use, natural capital, and flood management opportunities.
Results, initially mechanically derived from those scores and displayed on GIS, stimulate discussion of practicalities and issues, to provide decision-makers with material they can draw on, or that suggest areas requiring further examination or consideration. This is because such high-level, upstream modelling using broad-brush characterisation is not expected or intended to provide detailed advice, but instead to help frame or guide all subsequent stages of flood management or environmental growth, including any further involvement by those who care for the historic environment.
These landscape-based approaches form one of the ways that the historic environment and landscape can be ‘part of the solution’ by contributing to improved decision-making and more sustainable and locally distinctive forms of change.
Pete Herring FSA
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