Editorial

Abstract

I would like to extend a warm welcome to the August issue of Water Management, which presents an interesting and diverse selection of papers covering the broad themes of flood risk assessment, river engineering and hydraulic modelling. In the paper by Woods (2015), a new catchment-based method is developed to better integrate UK climate change data into design flood estimation and flood risk modelling. The other three papers focus on reporting results from physical modelling studies investigating new methods of scour control at bridge piers (Pagliara et al., 2015), the operating conditions of a new baffle-brush fish pass design (Kucukali and Hassinger, 2015), and the characteristics of air frequency distributions in self-aerated flows (Deng et al., 2015).In the first briefing paper of the issue, Deng et al. (2015) present results from an experimental study on the development of selfaerated open channel flows. The process of self-aeration within high-velocity open channel flows has particular relevance to spillway and chute design where the volume of entrained air can have a significant influence on the depth of the flowing water layer generated. Furthermore, it is known that the presence of entrained air in self-aerated flows can prevent or reduce damage due to cavitation. In their experiments, Deng et al. study the distribution of air-phase frequency in the developing self-aerated region of the open channel flows under different initial flow velocities. Their results demonstrate that the distribution of the air-water flow structure within the flow layers is a developing process involving the coexistence of entrapped and entrained air. Observed distributions of air frequency within these flow layers are also shown to be dependent on the air-water flow structure within the developing self-aerated region and to have a parametric dependence on the initial flow velocity.Improved understanding of linkages between future climate change scenarios, physical catchment responses and flood risk is essential to enable developers to design more sustainable floodresistant and resilient infrastructure. In the paper by Woods (2015), the author explores current limitations that exist in UK planning policy regulation, which adopt UK-wide average weightings to account for future climate change impacts on the magnitude of 1-in-100 year design flood events. It is noted that this deterministic approach cannot take account of more localised climate change impacts on the physical characteristics in the actual river catchments themselves. Within the paper, the author develops a novel approach to incorporate land-use data and additional climate change data obtained from UK climate projections 2009 (UKCP09) into current flood estimation and modelling frameworks. This combined methodology is then trialled in a case study at a development site on the River Cam near Cambridge, UK, with a series of scenarios tested for 1-in-100 year design flood events that reflect plausible changes to the physical catchment characteristics in the 2080s. When...