Trialling the rolling ball risk maps

At the heart of Loe Pool Forum’s (LPF) approach to addressing water environment risks is the idea of Integrated Catchment Management (ICM); “a process which promotes the coordinated development and management of water, land and related resources, in order to maximise the resultant economic and social welfare in an equitable manner without compromising the sustainability of vital ecosystems” (GWP, 2000: 10). Put in simpler terms, an integrated approach is about ensuring risk management strategies are sensitive to the needs and priorities of all catchment stakeholders. The challenge though, for catchment partnerships such as LPF, is to understand the different stakeholder’s needs and priorities in the first place.

Over the last three years, as part of his PhD, Tim Walker has been studying LPF and the challenges of delivering ICM in practice. Tim found that risk assessments were the primary way in which LPF identified and responded to water environment issues. The risk assessment process involves using available data and models to quantify the extent and location of risk. There are however are a number of problems with risk assessments for understanding and managing issues such as diffuse pollution:

1) Data on the sources, pathways and receptors of runoff are riddled with uncertainties.

2) The quantification of risk makes it difficult for stakeholder’s local knowledge to be taken into account.

3) Risk assessments conceal the multiple ways different catchment stakeholders frame the issues and their priorities and preferences for management.

Indeed, one of the central problems Tim identified for delivering ICM was the diversity of ‘frames’ held by different stakeholders about the same issue. A frame refers to an individual’s interpretation of an issue in relation to their own needs and priorities. Frames are important because they condition an individual’s understanding of both problems and solutions. Tim concludes that the resulting situation is one which can be termed ambiguous; ambiguous in the sense that there are multiple, and equally valid, ways to frame and prioritise the water issues in the catchment. For example, a situation of water shortage can be seen as a problem of ‘insufficient water supply’ for one actor, and one of ‘excessive water consumption’ for another one (Brugnach et al, 2007). Academic literature on framing suggests that by recognising and reflecting on the ambiguity reduced the potential for conflict between stakeholders about management strategies.

In order to address both the knowledge uncertainties and expose the ambiguities Tim has been working with Pool Forum (LPF) to develop a new mapping methodology using the Rolling Ball (RB) model. The RB is essentially an extremely detailed map of a catchments flow pathways. The RB uses data from digital terrain models to identify natural flow pathways determined by topography only. With representatives from the Environment Agency, Cornwall Wildlife Trust, Natural England and University of Exeter the mapping methodology was trialled in 2015. Through the pilot field walk exercise the methodology showed to have great advantages over standard ‘heat maps’ of risk and conventional flood inundation models because they:

1) Are high resolution, showing water pathways to ditch scale.

2) Provide a platform to engage with highly specific local knowledge.

3) Offer a visual prompt to discuss different framings of a specific issue.

4) Represent a collaborative learning experience which led to the identification of bespoke solutions.

rolling ball vimeo image

Click on me for a link to rolling ball video

The success of the RB based mapping exercise led to Catherine Leyshon and Tim Walker putting together an Impact Acceleration Account (IAA) application; with the aim to roll out the methodology to other catchment partnerships. Here is the video which accompanied the IAA application and provides a little more detail about the project.

  • Brugnach, M., Dewulf, A., Pahl-Wostl, C. & Tallieu, T. (2007) Towards a relational concept of uncertainty: Incorporating the human dimension. Basel, CAIWA conference.
  • Global Water Partnership (2000) Technical Advisory Committee Background Papers. No. 4 Integrated Water Resources Management.

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