Alexander H. McCluskey

Flipping the thin film model: Mass transfer by hyporheic exchange in gaining and losing streams

The exchange of mass between a stream and its hyporheic zone, or “hyporheic exchange”, is central to many important ecosystem services. In this paper we show that mass transfer across the streambed by linear mechanisms of hyporheic exchange in a gaining or losing stream can be represented by a thin film model in which: (a) the mass transfer coefficient is replaced with the average Darcy flux of water downwelling into the sediment; and (b) the driving force for mass transfer is “flipped” from normal to the surface (concentration difference across a boundary layer) to parallel to the surface (concentration difference across downwelling and upwelling zones). Our analysis is consistent with previously published analytical, computational, and experimental studies of hyporheic exchange in the presence of stream-groundwater interactions, and links stream network, advection-dispersion, and stochastic descriptions of solute fate and transport in rivers. This article is protected by copyright. All rights reserved.

Impacts of Hydrological Alterations on Water Quality

This chapter presents an overview of the response of water quality to hydrological alterations due to anthropogenic activities and how this drives the need for environmental water provisions. The chapter outlines the major driving processes of water quality change and highlights how interactions between water quantity and quality depend on the characteristics of individual catchments and anthropogenic influences. It also discusses management strategies to mitigate some water quality problems using environmental water releases. Salinity, water temperature, nutrient concentrations, and dissolved oxygen have been selected as both representative and important indicators of stream water quality. The flow-dependent processes, anthropogenic impacts, and management options have been discussed for each of these.

Early careers on ecohydraulics: challenges, opportunities and future directions

ABSTRACT Early career researchers (ECRs) play a critical role in our knowledge-based society, yet they are the most vulnerable group in the scientific community. As a young, interdisciplinary science, ecohydraulics is particularly reliant on ECRs for future progress. In 2014, the Early Careers on Ecohydraulics Network (ECoENet) was created to help the development of young researchers in this field. In this paper, we synthesize the outcomes of a workshop for ECRs organized by ECoENet in February 2016. We aim to show how the potential of ECRs can be maximized to drive progress in ecohydraulics. According to the most recent entrants to the field, major challenges lie in becoming more integrated as a discipline, developing a common vocabulary and a collective vision, engaging effectively with policy-makers, and encouraging public participation. ECRs need to develop their careers on an international scale in a way that crosses traditional disciplinary boundaries, including the social sciences, and allows them time to work at fundamental levels rather than focusing solely on individual applications. We propose a strategy to facilitate this by providing: a platform for disseminating research; an international support network; and a set of services for enhancing ECR training and experience.