Non-structural flood risk management

Joe Clarke - Research Engineer, with CH2M HILL, Cohort 4 (2009-10 start)

Supervisors: Luke Lovell (CH2M HILL)

Dr. Dawei Han (Academic supervisor), Dr. John Davis (Systems supervisor)

Framework to Assess the Benefits of NSRs

The model summarises a framework that can be used as the basis for an assessment of the benefits of NSRs independent of scale. It unites a hierarchical needs-based model (i.e. linking NSRs in terms of how they manage flood risk) with a functional model that identifies the actions that take place following the prediction of a flood (linking NSRs in with flood warning systems), both in terms of the official emergency response and community and individual responses. This is based on an expanded version of the Flood Warning Responses and Benefit Pathways (FWRBP) model developed by the Flood Hazard Research Centre (FHRC) at Middlesex University.

Barriers to Assessing the Benefits of NSRs at a National Scale

There are a number of issues that make it difficult to appraise the benefits of NSRs at a national scale. The first is a lack of generalizable data, as figures have not been collected for a significant period of time and measures have not matured enough to be able to study their whole lifecycle. This leads to the second issue: unknown future performance. This is compounded by issues of ownership: while flood defences are maintained by the Environment Agency or other authorities, property-level protection is currently passed on to households, and land management measures rely on continued cooperation from landowners. Planning and development control has a delayed benefit that may be reversed by a future planning decision. The relatively recent realisation that NSRs may play an important role in reducing flood risk also means that current national-scale methods are completely aimed at quantifying the benefits of assets (i.e. flood defences). This makes it difficult to fully incorporate NSRs into these methods: they have to be ‘bolted on’ to existing outputs. For example, it is assumed that flood defences that are operated or put in place when a flood is predicted are always operated in a timely fashion. In reality, this process depends on effective flood detection and forecasting systems.