Showing papers on "Water flow published in 2013"
TL;DR: Nanostrand-channelled graphene oxide ultrafiltration membranes with a network of nanochannels with a narrow size distribution and superior separation performance are reported, which offers a 10-fold enhancement without sacrificing the rejection rate compared with that of graphene oxide membranes.
Abstract: Pressure-driven ultrafiltration membranes are important in separation applications. Advanced filtration membranes with high permeance and enhanced rejection must be developed to meet rising worldwide demand. Here we report nanostrand-channelled graphene oxide ultrafiltration membranes with a network of nanochannels with a narrow size distribution (3-5 nm) and superior separation performance. This permeance offers a 10-fold enhancement without sacrificing the rejection rate compared with that of graphene oxide membranes, and is more than 100 times higher than that of commercial ultrafiltration membranes with similar rejection. The flow enhancement is attributed to the porous structure and significantly reduced channel length. An abnormal pressure-dependent separation behaviour is also reported, where the elastic deformation of nanochannels offers tunable permeation and rejection. The water flow through these hydrophilic graphene oxide nanochannels is identified as viscous. This nanostrand-channelling approach is also extendable to other laminate membranes, providing potential for accelerating separation and water-purification processes.
684 citations
TL;DR: It is suggested that the topic has still not received the attention that its importance deserves, in part because of the ready availability of software packages rooted firmly in the Richards domain, albeit that there is convincing evidence that this may be predicated on the wrong experimental method for natural conditions.
Abstract: The original review of macropores and water flow in soils by Beven and Germann is now 30 years old and has become one of the most highly cited papers in hydrology. This paper attempts to review the progress in observations and theoretical reasoning about preferential soil water flows over the intervening period. It is suggested that the topic has still not received the attention that its importance deserves, in part because of the ready availability of software packages rooted firmly in the Richards domain, albeit that there is convincing evidence that this may be predicated on the wrong experimental method for natural conditions. There is still not an adequate physical theory linking all types of flow, and there are still not adequate observational techniques to support the scale dependent parameterizations that will be required at practical field and hillslope scales of application. Some thoughts on future needs to develop a more comprehensive representation of soil water flows are offered.
655 citations
TL;DR: In this article, the authors explored the use of high-resolution thermal imagery, chlorophyll fluorescence, structural and physiological indices (xanthophyll, carotenoids and blue/green/red B/G/R indices) calculated from multispectral and hyperspectral imagery as early indicators of water stress caused by Verticillium wilt infection and severity.
334 citations
TL;DR: In this article, the authors investigated the energy consumption of MCDI, and the fraction of energy that can be recovered during the ion desorption step of the MCDi, as a function of influent concentration, water flow rate and water recovery.
309 citations
TL;DR: This is the first holistic study focusing on the impacts of CeO2 and ZnO NPs in the life cycle of cucumber plants, and μ-XRF images exhibited Ce in the leaf vein vasculature, suggesting that Ce moves between tissues with water flow during transpiration.
Abstract: With the dramatic increase in nanotechnologies, it has become increasingly likely that food crops will be exposed to excess engineered nanoparticles (NPs). In this study, cucumber plants were grown to full maturity in soil amended with either CeO2 or ZnO NPs at concentrations of 0, 400, and 800 mg/kg. Chlorophyll and gas exchange were monitored, and physiological markers were recorded. Results showed that, at the concentrations tested, neither CeO2 nor ZnO NPs impacted cucumber plant growth, gas exchange, and chlorophyll content. However, at 800 mg/kg treatment, CeO2 NPs reduced the yield by 31.6% compared to the control (p ≤ 0.07). ICP-MS results showed that the high concentration treatments resulted in the bioaccumulation of Ce and Zn in the fruit (1.27 mg of Ce and 110 mg Zn per kg dry weight). μ-XRF images exhibited Ce in the leaf vein vasculature, suggesting that Ce moves between tissues with water flow during transpiration. To the authors’ knowledge, this is the first holistic study focusing on the ...
265 citations
TL;DR: By using the EMD method friction coefficient to determine the slip length, the paper overcome the limitations of NEMD simulations and comments on several issues concerning water flow rates in carbon nanotubes.
Abstract: The purpose of this paper is threefold. First, we review the existing literature on flow rates of water in carbon nanotubes. Data for the slip length which characterizes the flow rate are scattered over 5 orders of magnitude for nanotubes of diameter 0.81-10 nm. Second, we precisely compute the slip length using equilibrium molecular dynamics (EMD) simulations, from which the interfacial friction between water and carbon nanotubes can be found, and also via external field driven non-equilibrium molecular dynamics simulations (NEMD). We discuss some of the issues in simulation studies which may be reasons for the large disagreements reported. By using the EMD method friction coefficient to determine the slip length, we overcome the limitations of NEMD simulations. In NEMD simulations, for each tube we apply a range of external fields to check the linear response of the fluid to the field and reliably extrapolate the results for the slip length to values of the field corresponding to experimentally accessible pressure gradients. Finally, we comment on several issues concerning water flow rates in carbon nanotubes which may lead to some future research directions in this area.
243 citations
TL;DR: In this article, the authors presented a two-dimensional glacier drainage system model (GlaDS) that couples distributed and channelized subglacial water flow, and applied it to a mountain glacier and forced with meltwater calculated by a temperature index model.
Abstract: [1] We present a two-dimensional Glacier Drainage System model (GlaDS) that couples distributed and channelized subglacial water flow. Distributed flow occurs through linked cavities that are represented as a continuous water sheet of variable thickness. Channelized flow occurs through Rothlisberger channels that can form on any of the edges of a prescribed, unstructured network of potential channels. Water storage is accounted for in an englacial aquifer and in moulins, which also act as point sources of water to the subglacial system. Solutions are presented for a synthetic topography designed to mimic an ice sheet margin. For low discharge, all the flow is accommodated in the sheet, whereas for sufficiently high discharge, the model exhibits a channelization instability which leads to the formation of a self-organized channel system. The random orientation of the network edges allows the channel system geometry to be relatively unbiased, in contrast to previous structured grid-based models. Under steady conditions, the model supports the classical view of the subglacial drainage system, with low pressure regions forming around the channels. Under diurnally varying input, water flows in and out of the channels, and a rather complex spatiotemporal pattern of water pressures is predicted. We explore the effects of parameter variations on the channel system topology and mean effective pressure. The model is then applied to a mountain glacier and forced with meltwater calculated by a temperature index model. The results are broadly consistent with our current understanding of the glacier drainage system and demonstrate the applicability of the model to real settings.
239 citations
TL;DR: Levels of PFOS and PFOA in water dropped exponentially along the current, and their proportions were decreased gradually with the increasing depth in sediment cores, indicating no bioaccumulation potentials for short-chain PFAAs in aquatic species.
Abstract: Short-chain perfluoroalkyl acids (PFAAs), which have less than seven fluorinated carbons, have been introduced as substitutes for eight-carbon homologue products. In this study, water, sediment, and biological samples (fish and plant) were collected from Tangxun Lake, which is located near a production base of the fluorochemical industry in Wuhan, China. Perfluorobutane sulfonate (PFBS) and perfluorobutanoic acid (PFBA) were the predominant PFAAs in surface water, with average concentrations of 3660 ng/L and 4770 ng/L, respectively. However, perfluorooctane sulfonate (PFOS) was the most abundant PFAA in sediments, with an average concentration of 74.4 ng/g dw. The organic carbon normalized distribution coefficients (KOC) indicated that short-chain PFAAs (CF2 < 7) tended to have lower adsorption potentials than PFOS, perfluorooctanoic acid (PFOA), and longer perfluoroalkyl chain compounds. PFBS and PFBA could transport to a farther distance in the horizontal direction along the water flow and infiltrate in...
234 citations
TL;DR: It is shown that formation of hexagonal ice bilayer in between the flakes as well as melting transition of ice at the edges of flakes are crucial to realize the perfect water permeation across the whole stacked structures, highlighting a unique water dynamics in randomly connected two-dimensional spaces.
Abstract: Water inside the low-dimensional carbon structures has been considered seriously owing to fundamental interest in its flow and structures as well as its practical impact. Recently, the anomalous perfect penetration of water through graphene oxide membrane was demonstrated although the membrane was impenetrable for other liquids and even gases. The unusual auxetic behavior of graphene oxide in the presence of water was also reported. Here, on the basis of first-principles calculations, we establish atomistic models for hybrid systems composed of water and graphene oxides revealing the anomalous water behavior inside the stacked graphene oxides. We show that formation of hexagonal ice bilayer in between the flakes as well as melting transition of ice at the edges of flakes are crucial to realize the perfect water permeation across the whole stacked structures. The distance between adjacent layers that can be controlled either by oxygen reduction process or pressure is shown to determine the water flow thus highlighting a unique water dynamics in randomly connected two-dimensional spaces.
228 citations
TL;DR: In this article, a simple one-dimensional morphodynamic model of a sediment capacitor was proposed to predict the watershed threshold for debris flow initiation in a burned or alpine setting, and the model reproduces the essential patterns in surge magnitude and frequency with rainfall intensity observed at the two field sites and provides a new framework for predicting the runoff threshold.
Abstract: [1] Runoff during intense rainstorms plays a major role in generating debris flows in many alpine areas and burned steeplands. Yet compared to debris flow initiation from shallow landslides, the mechanics by which runoff generates a debris flow are less understood. To better understand debris flow initiation by surface water runoff, we monitored flow stage and rainfall associated with debris flows in the headwaters of two small catchments: a bedrock-dominated alpine basin in central Colorado (0.06 km2) and a recently burned area in southern California (0.01 km2). We also obtained video footage of debris flow initiation and flow dynamics from three cameras at the Colorado site. Stage observations at both sites display distinct patterns in debris flow surge characteristics relative to rainfall intensity (I). We observe small, quasiperiodic surges at low I; large, quasiperiodic surges at intermediate I; and a single large surge followed by small-amplitude fluctuations about a more steady high flow at high I. Video observations of surge formation lead us to the hypothesis that these flow patterns are controlled by upstream variations in channel slope, in which low-gradient sections act as “sediment capacitors,” temporarily storing incoming bed load transported by water flow and periodically releasing the accumulated sediment as a debris flow surge. To explore this hypothesis, we develop a simple one-dimensional morphodynamic model of a sediment capacitor that consists of a system of coupled equations for water flow, bed load transport, slope stability, and mass flow. This model reproduces the essential patterns in surge magnitude and frequency with rainfall intensity observed at the two field sites and provides a new framework for predicting the runoff threshold for debris flow initiation in a burned or alpine setting.
195 citations
TL;DR: In this article, the Forchheimer equation and Izbash's law have been used to quantify the nonlinear effect of fracture flow in non-mated fractures under variable confining stress.
TL;DR: In this article, a new global database of hydraulic conductivity measured by ten-sion infiltrometer under field conditions was collated, and the results of their analyses on this data set contrast markedly with those of ex- isting algorithms used to estimate K. The data suggests that Ks depends more strongly on bulk density, or- ganic carbon content and land use.
Abstract: Due to inadequate data support, existing algo- rithms used to estimate soil hydraulic conductivity, K, in (eco)hydrological models ignore the effects of key site fac- tors such as land use and climate and underplay the signifi- cant effects of soil structure on water flow at and near satura- tion. These limitations may introduce serious bias and error into predictions of terrestrial water balances and soil mois- ture status, and thus plant growth and rates of biogeochem- ical processes. To resolve these issues, we collated a new global database of hydraulic conductivity measured by ten- sion infiltrometer under field conditions. The results of our analyses on this data set contrast markedly with those of ex- isting algorithms used to estimate K. For example, saturated hydraulic conductivity,Ks, in the topsoil (< 0.3 m depth) was found to be only weakly related to texture. Instead, the data suggests that Ks depends more strongly on bulk density, or- ganic carbon content and land use. In this respect, organic carbon was negatively correlated withKs, presumably due to water repellency, whileKs at arable sites was, on average, ca. 2-3 times smaller than under natural vegetation, forests and perennial agriculture. The data also clearly demonstrates that clay soils have smaller K in the soil matrix and thus a larger contribution of soil macropores to K at and near saturation.
TL;DR: In this paper, the authors investigated the consequences of hydropower dams for the Mekong region as well as the role of supranational players, such as Mekong River Commission and the Greater Mekong Subregion Initiative, on the hydopower debate.
Abstract: Hydropower developments along the main stem of the Mekong River and its tributaries cause transboundary effects within the Mekong Basin Region, which comprises parts of six countries. On the one hand, the provision of hydropower triggers economic development and helps to meet the rising energy demand of the Mekong riparian countries, especially China, Thailand, and Vietnam. On the other hand, the negative impact of dam construction, mainly altered water flow and sediment load, has severe impacts on the environment and the livelihoods of the rural Mekong population. Several discrepancies exist in the needs, demands, and challenges of upstream versus downstream countries. Against the common apprehension that downstream countries are powerlessly exposed to mainly negative impacts whereas upstream countries unilaterally benefit from hydropower, the authors argue that upstream–downstream relations are not really clear-cut. This conclusion is based on a consideration of the complex power play between Mekong riparians, with a focus on recent power trade interactions. The article investigates the consequences of hydropower dams for the Mekong region as well as the role of supranational players, such as the Mekong River Commission and the Greater Mekong Subregion Initiative, on the hydropower debate. It is not nations that are the winners or losers in the hydropower schemes in the Mekong, but rather parts of the riparian population: a few influential and powerful elites versus the large mass of rural poor.
TL;DR: Flow sensing plays an essential role in predator evasion by facilitating a response prior to a predator's strike.
Abstract: The ability of fish to evade predators is central to the ecology and evolution of a diversity of species. However, it is largely unclear how prey fish detect predators in order to initiate their escape. We tested whether larval zebrafish ( Danio rerio ) sense the flow created by adult predators of the same species. When placed together in a cylindrical arena, we found that larvae were able to escape 70% of predator strikes (mean escape probability P escape=0.7, N =13). However, when we pharmacologically ablated the flow-sensitive lateral line system, larvae were rarely capable of escape (mean P escape=0.05, N =11). In order to explore the rapid events that facilitate a successful escape, we recorded freely swimming predators and prey using a custom-built camera dolly. This device permitted two-dimensional camera motion to manually track prey and record their escape response with high temporal and spatial resolution. These recordings demonstrated that prey were more than 3 times more likely to evade a suction-feeding predator if they responded before ( P escape=0.53, N =43), rather than after ( P escape=0.15, N =13), a predator's mouth opened, which is a highly significant difference. Therefore, flow sensing plays an essential role in predator evasion by facilitating a response prior to a predator's strike.
TL;DR: In this article, a comprehensive comparison of the characteristics between the two crushing methods indicates that the wet crushing results in an enrichment of each component in spent lithium-ion batteries to fine fractions because of the scouring action of water flow, which makes the fine products complicated and lost.
TL;DR: In this paper, a detailed three-dimensional model, which integrates current knowledge of soil and root water flow equations, was proposed to deduct a one-dimensional effective behavior at the plant scale and to propose improvements for the four functions used in the macroscopic sink term.
Abstract: The process description of plant transpiration and soil water uptake in macroscopic root water uptake models is often based on simplifying assumptions that no longer reflect, or even contradict, the current status of knowledge in plant biology. The sink term in the Richards equation for root water uptake generally comprises four terms: (i) a root resistance function, (ii) a soil resistance function, (iii) a stress function, and (iv) a compensation function. Here we propose to use a detailed three-dimensional model, which integrates current knowledge of soil and root water flow equations, to deduct a one-dimensional effective behavior at the plant scale and to propose improvements for the four functions used in the macroscopic sink term. We show that (i) root hydraulic resistance may be well defined by the root length density but only for homogeneous lateral conductances and no limiting xylem conductance—in other cases a new function depending on the root hydraulic architecture should be used; (ii) soil resistance cannot be neglected, in particular in the rhizosphere where specific processes may occur that alter the soil hydraulic properties and therefore affect uptake; (iii) stress and compensation are two different processes, which should not be linked explicitly; (iv) there is a need for a clear definition of compensatory root water uptake independent of water stress; (v) stress functions should be defined as a maximal actual transpiration in function of an integrated root–soil interface water head rather than in terms of local bulk water heads; and (vi) nonlinearity in the stress function is expected to arise if root hydraulic resistances depend on soil matric head or when it is defined as a function of the bulk soil water head.
TL;DR: In this article, the authors focus on nine ecosystem services (e.g., aesthetic, spiritual, recreation, water flow regulation, carbon sequestration, climate change adaptation, pollination, biodiversity potential, and noise attenuation) along a rural-urban gradient.
TL;DR: The Source IMS is an integrated modelling environment containing algorithms and approaches that allow defensible predictions of water flow and constituents from catchment sources to river outlets at the sea, designed and developed to underpin a wide range of water planning and management purposes.
Abstract: Management of regulated water systems has become increasingly complex due to rapid socio-economic growth and environmental changes in river basins over recent decades. This paper introduces the Source Integrated Modelling System (IMS), and describes the individual modelling components and how they are integrated within it. It also describes the methods employed for tracking and assessment of uncertainties, as well as presenting outcomes of two case study applications. Traditionally, the mathematical tools for water resources planning and management were generally designed for sectoral applications with, for example, groundwater being modelled separately from surface water. With the increasing complexity of water resources management in the 21st century those tools are becoming outmoded. Water management organisations are increasingly looking for new generation tools that allow integration across domains to assist their decision making processes for short-term operations and long-term planning; not only to meet current needs, but those of the future as well. In response to the need for an integrated tool in the water industry in Australia, the eWater Cooperative Research Centre (CRC) has developed a new generation software package called the Source IMS. The Source IMS is an integrated modelling environment containing algorithms and approaches that allow defensible predictions of water flow and constituents from catchment sources to river outlets at the sea. It is designed and developed to provide a transparent, robust and repeatable approach to underpin a wide range of water planning and management purposes. It can be used to develop water sharing plans and underpin daily river operations, as well as be used for assessments on water quantity and quality due to changes in: i) land-use and climate; ii) demands (irrigation, urban, ecological); iii) infrastructure, such as weirs and reservoirs; iv) management rules that might be associated with these; and v) the impacts of all of the above on various ecological indices. The Source IMS integrates the existing knowledge and modelling capabilities used by different state and federal water agencies across Australia and has additional functionality required for the river system models that will underpin the next round of water sharing plans in the country. It is built in a flexible modelling environment to allow stakeholders to incorporate new scientific knowledge and modelling methods as they evolve, and is designed as a generic tool suitable for use across different jurisdictions. Due to its structure, the platform can be extended/customised for use in other countries and basins, particularly where there are boundary issues.
TL;DR: In this article, the authors compared the performance of pre-and post-FTW installation in two stormwater retention ponds in Durham, North Carolina, and found that the higher percent coverage of FTW surface area produced improved pollutant removal.
TL;DR: In this article, an evacuated solar water heater is integrated with the desalination stills to evaluate the continuity production of distillate, and two identical portable solar wick and one basin solar stills were designed to evaluate their performance.
TL;DR: In this article, the authors numerically investigated the heat production potential from hot dry rock by water circulating through two horizontal wells, based on the geological data of well DP23-1 under the enhanced geothermal system (EGS) project at Desert Peak geothermal field.
TL;DR: In this article, a regenerative evaporative cooler was fabricated and tested for performance evaluation, which consists of the multiple pairs of finned channels in counter flow arrangement and thin porous layer coating was applied to the internal surface of the wet channel to improve surface wettability.
TL;DR: The present status of flow hydrodynamics within and around sea-cages is reviewed, providing a framework for understanding the spatial and temporal variability of key environmental parameters within and outside sea-Cages.
TL;DR: In this paper, the authors review the literature on the effects of common hydromorphological impacts (channel modification and flow modification) on the functioning of river ecosystems, and suggest three criteria (relevance, scale and sensitivity) in the selection of functional variables are suggested as a guide for the river scientists and managers.
Abstract: Because of the serious effects of pollution on water supply much closer attention has been paid to water quality than to other aspects of river integrity. However, channel form and water flow are relevant components of river health, and recent evidences show that their impairment threatens the services derived from them. In this article, we review the literature on the effects of common hydromorphological impacts (channel modification and flow modification) on the functioning of river ecosystems. There are evidences that even light hydromorphological impacts can have deep effects on ecosystem functioning, and that different functional variables differ in their responses. Three criteria (relevance, scale and sensitivity) in the selection of functional variables are suggested as a guide for the river scientists and managers to assess the ecological impacts of hydromorphological modifications.
TL;DR: The hydraulics of inner leaf tissues can have a strong impact on the dynamic responses of leaf water potential and stomata, and as a consequence on plant carbon economy and leaf expansion growth.
Abstract: The water status of plant leaves is dependent on both stomatal regulation and water supply from the vasculature to inner tissues. The present review addresses the multiple physiological and mechanistic facets of the latter process. Inner leaf tissues contribute to at least a third of the whole resistance to water flow within the plant. Physiological studies indicated that leaf hydraulic conductance (K leaf) is highly dependent on the anatomy, development and age of the leaf and can vary rapidly in response to physiological or environmental factors such as leaf hydration, light, temperature, or nutrient supply. Differences in venation pattern provide a basis for variations in K leaf during development and between species. On a short time (hour) scale, the hydraulic resistance of the vessels can be influenced by transpiration-induced cavitations, wall collapses, and changes in xylem sap composition. The extravascular compartment includes all living tissues (xylem parenchyma, bundle sheath, and mesophyll) that transport water from xylem vessels to substomatal chambers. Pharmacological inhibition and reverse genetics studies have shown that this compartment involves water channel proteins called aquaporins (AQPs) that facilitate water transport across cell membranes. In many plant species, AQPs are present in all leaf tissues with a preferential expression in the vascular bundles. The various mechanisms that allow adjustment of K leaf to specific environmental conditions include transcriptional regulation of AQPs and changes in their abundance, trafficking, and intrinsic activity. Finally, the hydraulics of inner leaf tissues can have a strong impact on the dynamic responses of leaf water potential and stomata, and as a consequence on plant carbon economy and leaf expansion growth. The manipulation of these functions could help optimize the entire plant performance and its adaptation to extreme conditions over short and long time scales.
TL;DR: In this paper, a Geographic Information System (GIS) based approach was designed to estimate and map the value of the biodiversity and ecosystem services in a biosphere reserve area, with the aim of proposing criteria for conservation plans that would include ecosystem services and biodiversity.
Book•
12 Dec 2013
TL;DR: In this article, the authors present a theoretical theory of water flow and heat transport in the subsurface of underground or groundwater systems and provide a detailed discussion of the thermal properties of aquifers.
Abstract: Introduction Motivation for the thermal use of underground or groundwater systems Importance of the local conditions Technical systems Energy demand and energy production Management of underground resources Impact on groundwater quality and ecology Geotechnical issues Regulatory issues Challenges related to design and management Scope of the book References Fundamentals Theory of water flow and heat transport in the subsurface Thermal property values References Analytical solutions Closed systems Open systems References Numerical solutions Two-dimensional horizontal numerical solutions Multidimensional numerical solutions Strategy for coupled flow and heat transport Some available codes for thermal transport modeling in groundwater References Long-term operability and sustainability Systems in low permeable media Thermal evolution in aquifers Further criteria of sustainability References Field methods Hydrogeological field methods Thermal response tests Thermal tracer test References Case studies Case study Altach (Austria) Limmat valley aquifer Zurich (Switzerland) Bad Wurzach (Germany) References Index
TL;DR: The authors in this article summarized the impact and legacy of the contributions of Wilfried Brutsaert and Jean-Yves Parlange (Cornell University) with respect to the current state-of-the-art understanding in hydraulic groundwater theory.
Abstract: Based on a literature overview, this paper summarizes the impact and legacy of the contributions of Wilfried Brutsaert and Jean-Yves Parlange (Cornell University) with respect to the current state-of-the-art understanding in hydraulic groundwater theory Forming the basis of many applications in catchment hydrology, ranging from drought flow analysis to surface water-groundwater interactions, hydraulic groundwater theory simplifies the description of water flow in unconfined riparian and perched aquifers through assumptions attributed to Dupuit and Forchheimer Boussinesq (1877) derived a general equation to study flow dynamics of unconfined aquifers in uniformly sloping hillslopes, resulting in a remarkably accurate and applicable family of results, though often challenging to solve due to its nonlinear form Under certain conditions, the Boussinesq equation can be solved analytically allowing compact representation of soil and geomorphological controls on unconfined aquifer storage and release dynamics The Boussinesq equation has been extended to account for flow divergence/convergence as well as for nonuniform bedrock slope (concave/convex) The extended Boussinesq equation has been favorably compared to numerical solutions of the three-dimensional Richards equation, confirming its validity under certain geometric conditions Analytical solutions of the linearized original and extended Boussinesq equations led to the formulation of similarity indices for baseflow recession analysis, including scaling rules, to predict the moments of baseflow response Validation of theoretical recession parameters on real-world streamflow data is complicated due to limited measurement accuracy, changing boundary conditions, and the strong coupling between the saturated aquifer with the overlying unsaturated zone However, recent advances are shown to have mitigated several of these issues The extended Boussinesq equation has been successfully applied to represent baseflow dynamics in catchment-scale hydrological models, and it is currently considered to represent lateral redistribution of groundwater in land surface schemes applied in global circulation models From the review, it is clear that Wilfried Brutsaert and Jean-Yves Parlange stimulated a body of research that has led to several fundamental discoveries and practical applications with important contributions in hydrological modeling
TL;DR: Water Accounting Plus (WA+) as discussed by the authors is a new framework designed to provide explicit spatial information on water depletion and net withdrawal processes in complex river basins by defining land use groups with common characteristics.
Abstract: Coping with water scarcity and growing competition for water among different sectors requires proper water management strategies and decision processes. A pre-requisite is a clear understanding of the basin hydrological processes, manageable and unmanageable water flows, the interaction with land use and opportunities to mitigate the negative effects and increase the benefits of water depletion on society. Currently, water professionals do not have a common framework that links depletion to user groups of water and their benefits. The absence of a standard hydrological and water management summary is causing confusion and wrong decisions. The non-availability of water flow data is one of the underpinning reasons for not having operational water accounting systems for river basins in place. In this paper, we introduce Water Accounting Plus (WA+), which is a new framework designed to provide explicit spatial information on water depletion and net withdrawal processes in complex river basins. The influence of land use and landscape evapotranspiration on the water cycle is described explicitly by defining land use groups with common characteristics. WA+ presents four sheets including (i) a resource base sheet, (ii) an evapotranspiration sheet, (iii) a productivity sheet, and (iv) a withdrawal sheet. Every sheet encompasses a set of indicators that summarise the overall water resources situation. The impact of external (e.g., climate change) and internal influences (e.g., infrastructure building) can be estimated by studying the changes in these WA+ indicators. Satellite measurements can be used to acquire a vast amount of required data but is not a precondition for implementing WA+ framework. Data from hydrological models and water allocation models can also be used as inputs to WA+.
TL;DR: It was demonstrated that no internal membrane fouling occurred and that the fouling layer actually consisted of a grown biofilm and was not a filter cake of accumulated bacterial cells, suggesting that the biofilm resistance is mainly attributed to EPS.