Under the guidance of PhD geography student Shaun Maskrey and the Environment Agency’s John Woods, Hebden Bridge residents and organisations last week attended the first of five workshops, where together we’ll create a model for reducing flood risks in the Hebden Water catchment.
I found this workshop interesting in itself – it also struck me that the participatory modelling process looks as though it could be useful for all kinds of local issues. So it’s also worth attending just to learn how this process works.
How Shaun’s participatory modelling process works
Through previous interviews with various Hebden Bridge people, Shaun had made a list of nine initial objectives for reducing flood risks in the Hebden Water catchment:
- reduce surface water runoff
- store and slowly release excess stormwater from appropriate areas
- create more space for water in the river
- improve land management
- manage the flow of surface water
- adopt water-sensitive approaches to construction and development – and demonstrate how properties can be retrofitted to be more resilient to flooding
- understand the current and future role of reservoirs
- raise awareness of what residents can do to prepare for flooding
- raise awareness of what residents can do to recover from flooding
Each of the two groups spent most of the workshop working through this list and coming up with “interventions”, or actions, that might help to achieve these objectives.
Finding out how certain it is that different flood risk reduction measures actually work
Shaun explained in his presentation that you need to know how certain or uncertain any model is about the cause and effect relationships it identifies between different variables. How certain can we be that any of the actions or interventions we think up will help to achieve the relevant flood risk reduction objective?
This is obviously a good question. Having some way of answering it will be vital in deciding what kinds of actions/interventions are likely to have the greatest chance of reducing flood risk.
For example, current knowledge about the effectiveness of changes to land use in reducing flood risks may be quite vague. A 2012 Land Use And Flood Risk Management workshop organised by the Northern Ireland Rivers Agency noted that,
“Presentations and the answers by presenters to questions from the floor suggested that afforestation is unlikely to deliver a significant reduction in run- off during extreme rainfall events. However wet woodland did offer some benefits as it slows the flow and may delay the onset of a flood.”
The Houses of Parliament Parliamentary Office of Science and Technology 2011 Note 396 on Natural Flood Management offers a summary of the policy drivers of this approach to reducing flood risks, its scientific basis, and the implementation of inland natural flood management strategies. It points towards the need for greater certainty about the effectiveness of various Natural Flood Management methods.
To help identify the degree of certainty of different bits of the model, Shaun will be using Bayesian networks. Here is his explanation of how this process works – explained in terms of finding out how certain we can be about the effectiveness of different processes involved in making a decent cup of tea!
Knowledge politics & the Pickering flood reduction project
One of Plain Speaker’s guiding principles is What if everything we think we know is wrong? I’m interested in exploring knowledge controversies as they play out and affect what actually happens in the real world.
How to reduce flood risks is a topic that comes under the heading of “knowledge controversies”. It seems that we simply don’t yet know enough to confidently decide what are the best things to do to reduce flood risk.
In the absence of knowledge – and even in the absence of knowledge about absence of knowledge – sometimes it can seem as if participants in discussions about how to reduce flood risks are trying to police proposals from an uncertain evidence base, and possibly without an awareness that the evidence base is uncertain.
A public research project into flood risk “knowledge controversies” has already been carried out in Pickering, North Yorkshire.
Update 3.1.2016: during the disastrous 2015 Boxing Day floods, Pickering’s natural, traditional flood alleviation measures worked – it was one of the few places in Yorkshire at risk of flooding that didn’t flood.
Outcomes of the first workshop
Shaun’s notes on the outcomes of the first workshop are downloadable here.