This issue of Engineering Sustainability covers the subjects of walkability, water management, groundwater as a medium for building cooling, and railway trackbed solutions, a disparity of topics that are of general interest. The paper by Reid on walkability is particularly interesting for its primary findings that pedestrian behaviour is so diverse and subject to so many local barriers that it cannot be treated in the same way as vehicle traffic, which is by comparison very highly regulated. This aspect of individual behaviour has important lessons for other areas of engineering in which behavioural change is going to be needed if we are to meet targets set for a more sustainable future. This theme is picked up on by Shirley-Smith and Butler, who comment on the successes and challenges associated with the BedZED development as pertaining to water. This is both timely and a masterpiece of observation for the lessons that it provides on an essential utility service and also for other technological ‘sustainable solutions’, which are so often proposed as the way of dealing with the problems of how we become more sustainable.
The paper on the use of groundwater as a cooling source for buildings is most interesting as a novel solution to a problem that we are likely to have to become ever more engaged with. Not only is the paper of general interest, it raises the essential questions that we should be asking, and translating to other spheres of activity, and sets about testing and answering them. It goes into an appropriate level of detail and enables those considering it as a solution to the important topic of building cooling, both in the UK as well as overseas, to be sure that they are not missing anything important in the decision-making processes. The final paper by Kiani et al. addresses one of the classic dilemmas that face engineers almost daily in their working lives - which is the more sustainable of the possible solutions, and on what basis should this judgement be made? In this case it concerns the decision of whether to use a simple ballasted solution for trackbed - a system that is readily maintainable (cleanable, recompactable to generate stiffness, adjustable to maintain levels, repairable by the introduction of new material, but flexible in all senses) - or a more rigid structural solution that is more durable, but less repairable. The metrics should extend beyond direct cost, of course, but what if the basis is energy, or ‘global warming potential’, and what if water pollution or solid waste metrics should be included? While the paper does not claim to provide all of the answers, what it does provide is a clear definition of the set of questions that need to be asked and therefore areas in which better data are needed.
As with all papers published in Engineering Sustainability, we would welcome discussion on these topics to extend the debate.
