Showing papers in "Wiley Interdisciplinary Reviews: Water in 2020"

Plastic debris in rivers

Abstract: Plastic pollution in aquatic ecosystems is an emerging environmental risk, as it may negatively impacts ecology, endangers aquatic species, and causes economic damage. Rivers are known to play a crucial role in transporting land-based plastic waste to the world's oceans, but riverine ecosystems are also directly affected by plastic pollution. To better quantify global plastic pollution transport and to effectively reduce sources and risks, a thorough understanding of origin, transport, fate, and effects of riverine plastic debris is crucial. In this overview paper, we discuss the current scientific state on plastic debris in rivers and evaluate existing knowledge gaps. We present a brief background of plastics, polymer types typically found in rivers, and the risk posed to aquatic ecosystems. Additionally, we elaborate on the origin and fate of riverine plas-tics, including processes and factors influencing plastic debris transport and its spatio-temporal variation. We present an overview of monitoring and modeling efforts to characterize riverine plastic transport, and give examples of typical values from around the world. Finally, we present an outlook to riverine plastic research. With this paper, we aim to present an inclusive and comprehensive overview of riverine plastic debris research to date and suggest multiple ways forward for future research. This article is categorized under: Science of Water > Water Quality Water and Life > Stresses and Pressures on Ecosystems.

Ensemble flood forecasting: Current status and future opportunities

Abstract: Ensemble flood forecasting has gained significant momentum over the past decade due to the growth of ensemble numerical weather and climate prediction, expansion in high performance computing, growing interest in shifting from deterministic to risk-based decision-making that accounts for forecast uncertainty, and the efforts of communities such as the international Hydrologic Ensemble Prediction Experiment (HEPEX), which focuses on advancing relevant ensemble forecasting capabilities and fostering its adoption. With this shift, comes the need to understand the current state of ensemble flood forecasting, in order to provide insights into current capabilities and areas for improvement, thus identifying future research opportunities to allow for better allocation of research resources. In this paper, we provide an overview of current research activities in ensemble flood forecasting and discuss knowledge gaps and future research opportunities, based on a review of 70 papers focussing on various aspects of ensemble flood forecasting around the globe. Future research directions include opportunities to improve technical aspects of ensemble flood forecasting, such as data assimilation techniques and methods to account for more sources of uncertainty, and developing ensemble forecasts for more variables, for example flood inundation, by applying techniques such as machine learning. Further to this, we conclude that there is a need to not only improve technical aspects of flood forecasting, but also to bridge the gap between scientific research and hydro-meteorological model development, and real-world flood management using probabilistic ensemble forecasts, especially through effective communication.

The behavioral turn in flood risk management, its assumptions and potential implications

Abstract: Department Urban and Environmental Sociology, Helmholtz Centre for Environmental Research – UFZ, Leipzig, Germany Institute of Environmental Science and Geography, University of Potsdam, Potsdam, Germany Joanneum Research Forschungsgesellschaft mbH, Graz, Austria Disaster Research Unit (DRU), Freie Universität Berlin, Berlin, Germany Department of Ecological Economics, Carl von Ossietzky Universität Oldenburg, Germany GFZ German Research Centre for Geosciences, Section Hydrology, Potsdam, Germany Institute of Psychology, University of Leipzig, Leipzig, Germany Institute of Mountain Risk Engineering, University of Natural Resources and Life Sciences, Vienna, Austria Department of Social Work, Bielefeld University of Applied Sciences, Bielefeld, Germany

Exposing the myths of household water insecurity in the global north: A critical review

Abstract: Peter Wall Institute for Advanced Study, University of British Columbia; PLUS Alliance; Texas AM University; U.S. National Science FoundationNational Science Foundation (NSF) [BCS-17759972]

Zero or not? Causes and consequences of zero-flow stream gage readings.

Abstract: Streamflow observations can be used to understand, predict, and contextualize hydrologic, ecological, and biogeochemical processes and conditions in streams. Stream gages are point measurements along rivers where streamflow is measured, and are often used to infer upstream watershed-scale processes. When stream gages read zero, this may indicate that the stream has fully dried; however, zero-flow readings can also be caused by a wide range of other factors. Our ability to identify whether or not a zero-flow gage reading indicates a dry fluvial system has far reaching environmental implications. Incorrect identification and interpretation by the data user can lead to hydrologic, ecological, and/or biogeochemical predictions from models and analyses. Here, we describe several causes of zero-flow gage readings: frozen surface water, flow reversals, instrument error, and natural or human-driven upstream source losses or bypass flow. For these examples, we discuss the implications of zero-flow interpretations. We also highlight additional methodss for determining flow presence, including direct observations, statistical methods, and hydrologic models, which can be applied to interpret causes of zero-flow gage readings and implications for reach- and watershed-scale dynamics. Such efforts are necessary to improve our ability to understand and predict surface flow activation, cessation, and connectivity across river networks. Developing this integrated understanding of the wide range of possible meanings of zero-flows will only attain greater importance in a more variable and changing hydrologic climate.

A review of freely accessible global datasets for the study of floods, droughts and their interactions with human societies

Abstract: The availability of planetary-scale geospatial datasets that can support the study of water-related disasters in the Anthropocene is rapidly growing. We review 124 global and free datasets allowing ...

Swimming alone? Why linking flood risk perception and behavior requires more than “it's the individual, stupid”

Abstract: A common assertion in discussions of flooding is that risk perception is critical and is linked to risk-mitigating behavior. Furthermore, many assert that the adverse effects of floods could be reduced by changes in risk communication, thereby influencing risk perception to foster mitigating behavior. We argue that these assertions are based on quite questionable underlying assumptions: That stakeholders are generally aware of flood risk, that they have the capacity to engage in disaster risk reduction, and that their actions can be effective. The belief in and policies influenced by these three questionable assertions support, in turn, policies that shift responsibility for flood risk reduction onto individuals and homeowners, without regard for social and spatial justice issues. In contrast, we argue that context matters to understanding the complexity of the relation between flood risk perception and behavior, local power relations, and other constraints and opportunities that affect stakeholders. While the academic community has long played a pivotal role in supporting practical flood risk management, future research should take a more critical perspective on the underlying assumptions and focus on improving coordination across theories, methods, and variables, fostering comparative studies across disciplines, contexts, and scales. This article is categorized under: Engineering Water > Planning Water Human Water > Water as Imagined and Represented Science of Water > Water Extremes.

Historical development of rainfall-runoff modeling

Abstract: Rainfall-runoff models are used across academia and industry, and the number and type have proliferated over time. In this primer we briefly introduce the key features of these models and provide an overview of their historical development and drivers behind those developments. To complete the discussion there is a brief section on model choice including model intercomparison. We also seek to clarify jargon terms for readers new to this area.

A review of the pesticide MCPA in the land‐water environment and emerging research needs

Abstract: Funding information Horizon 2020 Framework Programme, Grant/Award Number: 727450; Special EU Programmes Body, Grant/Award Number: IVA5018 Abstract Due to its high solubility and poor adsorption to the soil matrix, the postemergence herbicide 2-methyl-4-chlorophenoxyacetic acid (MCPA) is susceptible to transport into surface and groundwater bodies, where it can result in compromised water quality and breaches of legislative standards. However, there is still poor understanding of catchment scale dynamics and transport, particularly across heterogeneous hydrogeological settings. While it is known that MCPA degrades under aerobic conditions, negligible breakdown can occur in anaerobic environments, potentially creating a legacy in saturated soils. Fast runoff pathways post application are likely transport routes, but the relative contribution from the mobilization of legacy MCPA from anaerobic zones has yet to be quantified, making the delineation of MCPA sources encountered during monitoring programs challenging. While ecotoxicological effects have been examined, little is known about the interaction of MCPA (and its degradation products) with other pesticides, with nutrients or with colloids, and how this combines with environmental conditions to contribute to multiple stressor effects. We examine the state of MCPA knowledge, using case study examples from Ireland, and consider the implications of its widespread detection in waterbodies and drinking water supplies. Research themes required to ensure the sustainable and safe use of MCPA in an evolving agricultural, social and political landscape are identified here. These include the need to identify mitigation measures and/or alternative treatments, to gain insights into the conditions governing mobilization and attenuation, to map pathways of migration and to identify direct, synergistic and antagonistic ecotoxicological effects.

River ecosystem conceptual models and non‐perennial rivers: A critical review

Abstract: Conceptual models underpin river ecosystem research. However, current models focus on continuously flowing rivers and few explicitly address characteristics such as flow cessation and drying. The applicability of existing conceptual models to nonperennial rivers that cease to flow (intermittent rivers and ephemeral streams, IRES) has not been evaluated. We reviewed 18 models, finding that they collectively describe main drivers of biogeochemical and ecological patterns and processes longitudinally (upstream-downstream), laterally (channel-riparian-floodplain), vertically (surface water-groundwater), and temporally across local and landscape scales. However, perennial rivers are longitudinally continuous while IRES are longitudinally discontinuous. Whereas perennial rivers have bidirectional lateral connections between aquatic and terrestrial ecosystems, in IRES, this connection is unidirectional for much of the time, from terrestrial-to-aquatic only. Vertical connectivity between surface and subsurface water occurs bidirectionally and is temporally consistent in perennial rivers. However, in IRES, this exchange is temporally variable, and can become unidirectional during drying or rewetting phases. Finally, drying adds another dimension of flow variation to be considered across temporal and spatial scales in IRES, much as flooding is considered as a temporally and spatially dynamic process in perennial rivers. Here, we focus on ways in which existing models could be modified to accommodate drying as a fundamental process that can alter these patterns and processes across spatial and temporal dimensions in streams. This perspective is needed to support river science and management in our era of rapid global change, including increasing duration, frequency, and occurrence of drying.

Troubled waters: Maori values and ethics for freshwater management and New Zealand's fresh water crisis

Abstract: The landmass of Aotearoa New Zealand totals some 268,000 square kilometres, including 425,000 km of rivers, more than 4000 lakes and approximately 200 aquifers (MfE 2007). For Aotearoa New Zealand’s indigenous Maori, these freshwater bodies are part of a complex system of genealogical relationships from which derive the traditional Maori knowledge, values and ethics which shape Maori customary practices for freshwater monitoring and freshwater management. The rupture of these relationships through a century and a half of colonization and industrialization and the dispossession of Maori from their lands and waters also dispossessed Maori of their rights and responsibilities to enact traditional customary practices of kaitiakitanga, stewardship of the natural environment. In 2017 Aotearoa New Zealand’s freshwater systems were designated as amongst the worst in the world. Today they are continuing to degrade. This article focuses on Maori traditional knowledge, ethics and values for freshwater monitoring and management. The article reviews the impact of colonization and development on Aotearoa New Zealand’s freshwater systems, the extensive struggle by Maori for recognition of Maori traditional knowledge, rights and responsibilities regarding waterways, and the development of contemporary Maori models for freshwater monitoring and management. Treaty settlements and other legislative initiatives have also catalyzed changes in freshwater management. Faced with catastrophic climatic impacts on freshwater systems and implications for the wellbeing of species and communities, questions of how to ethically manage freshwater are critical. Maori freshwater ethics, values and practices provide a model of renewal and possibility, although one that is not without contest.

The need for green and atmospheric water governance

Abstract: A review of the literature on water governance reveals that most studies focus on blue water governance; while there is some literature on green and atmospheric water, explicit literature on how to govern green and atmospheric water is lacking. Hence, this paper addresses the question: What are the arguments for governing green and atmospheric water? In order to address this question, we have undertaken a scoping analysis of the literature on green and atmospheric water. We conclude that water governance must proactively address green and atmospheric water since: (a) blue water represents only a part of the available fresh water; (b) blue river basins represent only a subset of the wider systemic nature of water; (c) land use change has significant impacts on various water flows, which all may need to be governed; (d) climate variability and change influences blue, green, and atmospheric water availability; (e) an understanding of the socio‐ecological uses of the different colors of water is critical for a more optimal and legitimate governance of water; (f) new water technologies make it increasingly possible to modify the use of green and atmospheric water; and (g) global trade infrastructures pressurize local green water resources. Neglecting the need for explicit governance of green and atmospheric water could create new forms of “water grabbing” that would impact water availability beyond the basin scale.

Colloid transport through soil and other porous media under transient flow conditions—A review

Abstract: Author(s): Wang, C; Wang, R; Huo, Z; Xie, E; Dahlke, HE | Abstract: Understanding colloid transport in porous media under transient-flow conditions is crucial in understanding contaminant transport in soil or the vadose zone where flow conditions vary constantly. In this article, we provide a review of experimental studies, numerical approaches, and new technologies available to determine the transport of colloids in transient flow. Experiments indicate that soil structure and preferential flow are primary factors. In undisturbed soils with preferential flow pathways, macropores serve as main conduits for colloid transport. In homogeneously packed soil, the soil matrix often serves as filter. At the macroscale, transient flow facilitates colloid transport by frequently disturbing the force balance that retains colloids in the soil as indicated by the offset between colloid breakthrough peaks and discharge peaks. At the pore-scale and under saturated condition, straining, and attachment at solid–water interfaces are the main mechanisms for colloid retention. Variably saturated conditions add more complexity, such as immobile water zones, film straining, attachment to air–water interfaces, and air–water–solid contact lines. Filter ripening, size exclusion, ionic strength, and hydrophobicity are identified as the most influential factors. Our review indicates that microscale and continuum-scale models for colloid transport under transient-flow conditions are rare, compared to the numerous steady-state models. The few transient flow models that do exist are highly parameterized and suffer from a lack of a priori information of required pore-scale parameters. However, new techniques are becoming available to measure colloid transport in real-time and in a nondestructive way that might help to better understand transient flow colloid transport. This article is categorized under: Science of Water g Hydrological Processes Science of Water g Water Quality.