Investment in flood warning and defence in England and Wales is justified on a range of economic, environmental and social factors. During the 1970s, 80s and early 90s, research was carried out which led to the development of methodologies for assessing the economic impact of flooding based on an estimate of the damage to property when a flood of a certain magnitude occurs. The research included consideration of some of the social effects of flooding, adding a second dimension which further supported the case for investment in flood defences and in monitoring, forecasting and warning systems, and which led to the development of a comprehensive flood and coastal defence strategy for England & Wales.

Over the years, as society has become more conscience of the environment we live in and the impact we have upon it, we have seen the business cases for major investments of public money increasingly start to consider less quantifiable or “softer,” more intangible benefits such as reducing the changes to water courses and maintaining flow patterns, reduced visual impact and enhancement of recreational facilities. Consideration of these environmental factors has introduced yet another influential dimension. The last decade has seen the world starting to face up to our responsibilities for creating a sustainable future to halt the damage we are causing to our environment and society, and to restore it for future generations. This has introduced a stronger social dimension and is reinforcing the environmental influence, leading us towards an approach that is often referred to as the “triple bottom line.”

Flood Defence and Flood Warning Investment Strategies

Flood Defence Business Cases. Historically, spending on improving flood defences has relied on being able to justify a net benefit by assessing potential damage and its associated costs and comparing this with the costs of mitigation. The development of a flood defence (FD) scheme was ‘incentivised’ by minimising engineering costs so that the cost benefit ratio could be optimised. Increasingly over the past twenty years, however, the importance of designing flood defences that are more in sympathy with their environmental context has been established. Whilst the methods have not been sufficiently developed to fully balance the benefits of different environmental options economically, the views of the community stakeholders have played an increasingly important part in determining whether the environmental aspects incorporated within an engineering design are acceptable. In that context, the concept of the ‘triple bottom line’ has entered the engineering of flood defences, but it is probably fair to say that it is driven mainly by regulation rather than a more balanced approach driven by social responsibility.

This article is taken from a paper delivered at the 39th DEFRA Conference on Flood & Coastal Management held at the University of York from 30th June to 1st July 2004 . DEFRA is the UK government department responsible for the environment, food and rural affairs , and it influences policy and direction on issues such as sustainability. DEFRA's chief engineer chaired the conference assisted by most of his senior management team and delegates from the environment agencies representing England , Wales , Scotland and Ireland. Among the international delegates were several representatives from Scandinavia and Eastern Europe.

The conference dedicated an entire session to sustainability, although it was clear that few had grasped the totality of the subject and most of the papers focused only on specific issues such as biodiversity or sustainable flood defenses . The PB paper was therefore very timely in that it “set the scene” and served to open up the debate to the wider issues that need to be addressed if we are serious about building a sustainable future for our children. In his keynote address, the Government's Chief Scientific Officer, Sir David King, was keen to emphasise the important role scientists and engineers play in securing the economic, environmental and social well-being of the country ; a sentiment that is easy to link to our sustainable values. The conference provided the opportunity to promote some of the IT toolbox being developed by PB, such as PRISM, visualization and immersive virtual reality as so excitingly presented by Doug Eberhard, Chief Technical Officer, at the T E P. The audience feedback for use of this technology was most encouraging.

Flood Warning Business Cases. Flood warning (FW), by definition, has a significant social component in that it is predicated on protecting property and life by providing warnings to people living within at-risk areas. An economic model for calculating the damage avoided due to flood warnings for an average year was developed in the 1990s and has since been augmented by the Environment Agency to the following:

Figure 1: Five Stages of the Flood Event Cycle

Figure 2: Comparative Value Analysis (CVA) Model

Figure 3: Indicative Influence Zones for Flood Defence and Flood Warning

Figure 4: Hierarchy of Plans from FCDPAG2

Table 1: Sustainability-Related Definitions Extracted from DEFRA’s FCDPAG1

Each term has been given a rigorous definition to avoid double counting, omitting or unfair bias, and to allow the formula to be used on a range of scales from local flood risk areas to national strategies. As well as providing an economic assessment of the savings that warnings produce, the model also helps to focus attention on the potential for improvement in each factor and how investment in flood warning should be planned to maximise the overall savings to the community. The difficultly is relating potential investment to an improvement in any factor because the things that we invest in do not normally directly contribute to just one; e.g. investment in telemetry technology can result in earlier detection, more accurate predictions and earlier warning which, in turn, eventually result in improvements to a number of the factors. Some potential investments alone would not increase any of the factors directly, but are highly valuable in facilitating other schemes that do have a more direct benefit.

The solution used to overcome this complexity was the comparative value analysis (CVA) model. In this model we took the five stages of the flood event cycle (Figure 1), and related the investment made towards enhancing the capability in each of these areas to the six benefit factors given above and also indirectly when one capability supports another.

The complex interactions are shown in Figure 2. The CVA model solves these complex interactions to calculate how any profile of proposed investments in capabilities translates into investment in the benefits factors.

Sustainable Development

When properly applied, sustainable development — that which meets the needs of the present without compromising the ability of future generations to meet their own needs—is part of the process rather than being a product. Hence by applying sustainable development practices to FD and FW we optimise the process that produces an effective balancing of the triple bottom line. Sustainable development should not compromise the economic business case but add to it.

The UK government has addressed how the sustainability issue relates to FD and FW as part of the DEFRA Flood & Coastal Defence Project Appraisal Guidance series (FCDPAG) process. Table 1 provides a selection of definitions extracted from the first of the series. Interestingly, the social or community references are implied rather than explicit within these definitions.

Looking to the Future

New Methods. The more recent FD & FW projects have tried to address sustainability at some level; however, new methodologies are needed to ensure that the sustainable development agenda is appropriately and uniformly applied to all projects. To address this, not only in FD but also across the broad range of projects, PB has established a methodology code named PRISM (Project Review Incorporating Sustainable Methodologies). PRISM applies the project manager’s “triangle of balance” (usually associated with quality/time/cost) with economic/environment/social components, thereby adapting it to suit the sustainable development agenda. This methodology is continually developing and requires specific application to different project types; however, it provides a consistent framework for ensuring that the sustainability issues are understood at the outset of a project and appropriate consideration is given as the development process progresses.

PRISM can be used to measure the collective, relative performance of each of the three components and plots the results along a fourth axis, thereby generating a 3D prism. Economic, environmental and social indicators are measured in relative terms within a project. Best practice in environmental and social mitigation represents a score of 100 percent, with the minimum acceptable standard scoring 0 percent. The economic scale represents the comparative value/cost benefit ratio (and/or affordability) of the various options.

At the macro level, applying it to FD and FW reveals an approximate influence zone as illustrated by Figure 3 (note this excludes the quantification axis and therefore shows the base of the 3D PRISM only).

In developing FD projects from concept to completion, the use of a methodology such as PRISM makes it possible to establish a measured approach to sustainable development and its influence on the economics of a project. Classifying the benefits into economic, environmental and social categories should help overcome some of the difficulties raised by unquantifiable (in economic terms) benefits and by articulating intangible (indefinable) benefits, e.g., effects on wildlife habitats, interference with natural processes and changing recreational patterns.

This methodology has not yet been applied from the outset to FD and FW applications. Although essentially encouraging best practice in a holistic project context, it nevertheless requires an additional element within the project procurement phase so that it can become part of the professional team’s scope, much as environmental assessment was introduced in the 1980s.

New Perspectives We are encouraged by recent regulations to:

• Look at our river and coastal environment in a much more holistic and integrated way by developing a hierarchy of plans (Figure 4),
• Take a more integrated approach to management of land and water use within river basins across Europe, with a focus on ecological outcomes rather than the more prescriptive approaches of previous legislation
• Make informed, responsible decisions about the development of our FD & FW systems that satisfy our sustainable objectives.

If most of the predictions about climate change are accurate, then we will see a significant increase in the intensity and incidence of flooding. The conventional approach would lead us to a major investment in new or reinforced defences and in sophisticated FW and information systems. Whilst such measures may be the answer, these would be built from natural or recycled materials using less intrusive construction techniques and would enhance rather than blemish the landscape. In the future, it may even be that we define sustainability such that we only invest in defences to protect against unnatural (man-made) processes. River and coastal flooding may then be accepted as a natural process with a value in the longer term and the solutions may be focussed on such aspects as more effective warnings, better educated stakeholders, more informed people at risk, less permanent, more repairable dwellings and alternative transportation routes. This is where balanced triple bottom line techniques such as PRISM come to the fore. We should continue to invest in such models and particularly in the areas of research that are producing them.

Whatever our solution, be it for 10, 20, 50 or 100 years hence, we must ensure we build in sufficient flexibility and a review cycle that will allow us to regularly consider the selected strategy in the light of a better understanding of the development’s performance and society’s then current needs and values. We would, therefore, argue that a methodology that builds on the FDA and CVA financial models, but incorporates, in a more formulated manner, the other two bottom line components (environmental and social) is required.