The papers in this issue of Water Management reflect a number of trends in research activity associated with the management of water bodies and man-made assets. They demonstrate the increasing level of internationalisation of water management research. Having just returned from the excellent biannual 37th International Association for Hydro-Environment Engineering and Research World Congress held in Kuala Lumpur, Malaysia (IAHR, 2017), it is clear that the geographical spread of research into water management issues has clearly increased within the last decade, with a significant presence of researchers from Southeast Asia at the Congress. It is clear that given the number of talented young researchers at the Congress and the investment in new hydraulic research facilities and people by made by several governments in this region that the internationalisation of research in our area will continue. The papers in this issue also reflect the new challenges that the water management community faces; they describe new tools and approaches to deal with increasingly severe climate variabilities, the protection of the aquatic environment despite increasing human demands on water systems, and the need for better protection of infrastructure from river scour in terms of understanding its temporal behaviour and also introducing new probabilistic concepts of uncertainty and fragility.
The first paper of this issue by Kangrang et al. (2017) reports on a study that used new algorithms and optimisation techniques to define reservoir operational rules. Their approach is demonstrated using data obtained from a reservoir in Thailand. The study shows that the impact of the newly derived operational rules produced by their optimisation scheme was similar to rules produced by existing methods in a ‘normal’ climatic year. However the obtained rule-based operational curves for the ‘wet’ and ‘dry’ climatic years were clearly different from those from the normal year, indicating that as climate variability increases, new methods need to be developed to operate existing reservoirs in an optimal fashion.
Phosphorus is a key pollutant in many freshwater systems and better understanding of its transport mechanisms will be important for its future management. The second paper by Tang et al. (2017) describes investigations into phosphorus sorption and suspended sediment. This study involved careful laboratory experiments combined with field data collection. The authors found that phosphorus sorption and sorption rates were related to the prevailing flow velocity and suspended sediment concentrations. Based on these studies, equations were proposed to simulate these processes.
The third paper by Yu et al. (2017) again focussed on the interaction between in-channel hydraulics and fine-grained sediments. The paper describes a series of laboratory experiments conducted in an unusual U-shaped flume to examine the erosion processes of fine cohesive sediment that have collapsed onto the toe of the riverbank. The study demonstrated that the presence of a collapsed block of sediment could enhance downstream bank retreat and, additionally, in certain circumstances lead to enhanced downstream deposition.
The final two papers in this issue involve studies that aim to improve the capability of engineers to protect infrastructure that cross rivers. The two papers investigate the potential for scour damage to bridge piers and the use of bed sills to protect buried infrastructure such as pipelines. Bridge pier scour around uniform cylindrical piers has received considerable previous study. The paper by Oliveto and Marino (2017) reports on a laboratory study that focusses on the scour of bridge piers founded on piles. The study involves a long-duration experiment so that a state of equilibrium was achieved. This type of long-duration experiment also allowed the scour evolution to be carefully quantified and studied in depth, so that a new scour equation was proposed that could simulate the temporal scour variation.
In the final paper, new concepts and tools were introduced to examine the potential for failure of assets buried within a river bed. Flexible bed sills are often used to protect buried assets such as pipelines. The paper by Roca and Escarameia (2017) proposes a probabilistic-based design method for the design of bed sills potentially subject to damaging scour. This method aims to account for the uncertainties inherent in any riverbed scour process. The paper describes how to apply this methodology so as to estimate the annual probability of failure depending on various loading conditions. The potential for failure is described by the use of fragility curves; this use of probabilistic concepts is expected to lead to safer and potentially more cost-effective design.
This issue clearly demonstrates that the technical management of many aspects of water systems is a vibrant area of research, attracting both talented individuals and the support of society through funding from a number of governments. The civil engineering community needs to embrace this support from society and strive through the adoption of new innovative approaches to deliver better, more certain management of the water environment in a more cost-effective way so as to provide more widespread societal impact.
