Workshop report
Tuesday 28th September 2010 at Lancaster Environment Centre
Our event on September 28th, in conjunction with the RTPI Development Planning Network prompted a discussion across the planning community around developing a general framework and practical guidance for dealing with uncertainty, with a particular focus on flood data, modelling and mapping. Uncertainty could be particularly important in trying to project the impacts of future land use and climate change on flood risk, and the visualisation and communication of this uncertainty could have an impact on decision making within the planning and development communities.
The event attracted almost 30 delegates with a varied range of interest and responsibilities across flood risk mapping and development planning. Despite being very well advertised by RTPI, few actual planning professionals attended with the majority of delegates present involved in directly in the production/interpretation of flood risk maps.
The day began with an overview of the background to uncertainty estimation methods in flood risk mapping by Keith Beven followed by an overview from Kate Donovan of Project FOSTER – a KE project centred on communicating flood science to a group of Local Authorities in Central England.
Presentations from the meeting are available to view
- Keith Beven, Lancaster University Sources and understanding of uncertainty in data, modelling and mapping?
- Kate Donovan, University of Oxford Communicating flood science to Local Authorities – An introduction to FOSTER: Flood Organisation Science and Technology Exchange Research
The facilitated group Discussion Sessions (led by Simon McCarthy) allowed us to explore what aspects of visualising an uncertain flood risk are of particular importance to the planning and development community.
Discussion Session I dealt with ‘uncertainty in practice’ and 4 broad pre-selected groups (Government Agencies, Planners and Development Practitioners, Academics and Environmental Consultants) were asked to identify how and in what form they incorporated uncertainty into flood risk mapping and how that uncertainty was represented.
The planning group felt that there was no admission and therefore discussion of uncertainty across the profession. It was considered an admission of weakness to admit to ‘not knowing’ and the topic added ’grey areas’ to decision making which relied on definitive yes/no answers. The technical knowledge needed to understand and process the flood map information and construction was well beyond traditional planning knowledge and therefore expert guidance was always needed via Environment Agency staff. Nevertheless it was felt by some delegates that the planning process – as a process of negotiation – could embrace discussions around uncertainty and use them as an opportunity, particularly to incorporate green infrastructure and sustainable regeneration options across vulnerable urban areas.
This view was reinforced by the consultants group who raised the issue that PPS25, and the initial 90 day decision limit, did not allow for adequate negotiation of projects. Inclusion of uncertainty into the process might help more sensible decisions to be made – albeit that it might take more time and cost more. It would also help counteract the false impression of precision given by the use of standard prediction packages and the resulting crisp maps – although it is normal practice to carry out some sensitivity analysis of results based on professional judgment, even if results are not often communicated to users.
Subsequent Discussion Sessions were conducted in mixed delegate groups. The first of these aimed to identify sources of uncertainty and highlight which of these were most difficult to quantify. The second examined communicating and interpreting flood risk messages using mapping tools and the third centred on the need for guidelines for the development and planning community to help them embrace uncertainty within decision making. There was felt to be a concern that including uncertainty might simply lead to the use of worse case scenarios (i.e. less successful planning applications). There is still a need for standards to work to for different purposes, but including uncertainty might reduce the inflexibility of the current process that allows a crisp line on a map to dominate local knowledge. It would be important to communicate the assumptions used in producing uncertain flood risk maps to properly evaluate risk and choices.
It was felt that guidelines were most useful for the flood risk assessment professionals who are charged with producing flood risk maps. Future training opportunities that covered a non-technical overview of flood risk mapping methods was the preferred way forward for the planning community. It was also highlighted that the impact of flood risk on development and decision making as a discrete topic should be embraced across Planning Schools and planning qualifications to ensure looking forward that there is an improved understanding of the implications of flood risk across the profession.
