ALBERT

Description: Water, Vol. 10, Pages 1227: The Role of Attenuation and Land Management in Small Catchments to Remove Sediment and Phosphorus: A Modelling Study of Mitigation Options and Impacts Water doi: 10.3390/w10091227 Authors: Russell Adams Paul Quinn Nick Barber Sim Reaney It is well known that soil, hillslopes, and watercourses in small catchments possess a degree of natural attenuation that affects both the shape of the outlet hydrograph and the transport of nutrients and sediments. The widespread adoption of Natural Based Solutions (NBS) practices in the headwaters of these catchments is expected to add additional attenuation primarily through increasing the amount of new storage available to accommodate flood flows. The actual type of NBS features used to add storage could include swales, ditches, and small ponds (acting as sediment traps). Here, recent data collected from monitored features (from the Demonstration Test Catchments project in the Newby Beck catchment (Eden) in northwest England) were used to provide first estimates of the percentages of the suspended sediment (SS) and total phosphorus (TP) loads that could be trapped by additional features. The Catchment Runoff Attenuation Flux Tool (CRAFT) was then used to model this catchment (Newby Beck) to investigate whether adding additional attenuation, along with the ability to trap and retain SS (and attached P), will have any effect on the flood peak and associated peak concentrations of SS and TP. The modelling tested the hypothesis that increasing the amount of new storage (thus adding attenuation capacity) in the catchment will have a beneficial effect. The model results implied that a small decrease of the order of 5–10% in the peak concentrations of SS and TP was observable after adding 2000 m3 to 8000 m3 of additional storage to the catchment.

Description: Water, Vol. 10, Pages 1232: Values and Preferences for Domestic Water Use: A Study from the Transboundary River Basin of Mékrou (West Africa) Water doi: 10.3390/w10091232 Authors: Vasileios Markantonis Celine Dondeynaz Dionysis Latinopoulos Kostas Bithas Ioannis Trichakis Yèkambèssoun N’Tcha M’Po Cesar Carmona Moreno Water is indispensable for human life and sufficient domestic use is considered as a regularity in the western world. The conditions are substantially different in African countries where poverty and lack of life-supporting services prevail. The provision of domestic water is an essential problem, which requires action. The lack of sufficient funding for the development of infrastructure supports claims for citizen participation in related costs. However, can citizens pay and to what extend for sufficient water provision? The present study investigates a household’s willingness to pay for domestic water in the transboundary Mékrou River Basin in West Africa (Burkina Faso, Benin and Niger) and explores the payment for domestic water provision to poverty. The paper uses the results of a household survey that was undertaken in the Mekrou basin including a representative sample from all three countries. Based on this survey the paper presents basic socio-economic characteristics of the local population as well as qualitative water provision and management attributes. In the core of the econometric analysis the paper presents the results of the survey’s Contingent Valuation (CV) scenario estimating the households’ willingness to pay (WTP) for a domestic water provision. The households of the Mekrou basin are willing to pay 2.81 euro per month in average for a domestic water provision network but this is strongly related with the wealth of households. This finding although it may support the “user pays principle”, it also raises serious questions over the provision of water to poor households.

Description: Water, Vol. 10, Pages 1230: Transitioning to Sponge Cities: Challenges and Opportunities to Address Urban Water Problems in China Water doi: 10.3390/w10091230 Authors: Chris Zevenbergen Dafang Fu Assela Pathirana At present, the Sponge City Concept (SCC) is gaining ground, Sponge Cities technologies are becoming more and more accepted by Chinese city governments, and the first best practices are being shared. However, there are still many challenges ahead which hamper effective implementation and upscaling. This paper presents an overview of some opportunities and constraints for the take up of this approach and has drawn upon international experiences. In China at the national level, the State Council has set a progressive target for the SCC initiative to be achieved in 2030. This target seems to be ambitious as the time needed for integrative planning and design and implementation is much longer than traditional sectoral approaches often omitting to address social well-being, the (local) economy, and ecosystem health. This particularly holds true for the existing building stock. Transforming the existing building stock requires a long-term planning horizon, with urban restoration, regeneration, and modernization being key drivers for adapting the city to become a sponge city. A key challenge will be to align the sponge city initiative (SCI) projects with infrastructure and urban renovation portfolios. Moreover, substantial investment needs and a lack of reliable financing schemes and experience also provide a huge challenge for China. This calls for an integrative opportunistic strategy that creates enabling conditions for linking the SCI investment agenda with those from other sectors. These transformations cannot be made overnight: completing the transformation process will typically take a life time of one generation. The progress in sustainable urban water management is also impacted by innovations in technologies as well as in management strategies. These technological innovations create fertile ground for businesses to adapt state-of-the-art developments from around the world and contextualize them into fit-for-purpose products. China is well-placed to play a leading role in this process in the coming decade.

Description: Water, Vol. 10, Pages 1228: Study of Hydrodynamic Interference of Vertical-Axis Tidal Turbine Array Water doi: 10.3390/w10091228 Authors: Guangnian Li Qingren Chen Hanbin Gu The hydrodynamic interference between tidal turbines must be considered when predicting their overall hydrodynamic performance and optimizing the layout of the turbine array. These factors are of great significance to the development and application of tidal energy. In this paper, the phenomenon of hydrodynamic interference of the tidal turbine array is studied by the hydrodynamic performance forecast program based on an unsteady boundary element model for the vertical-axis turbine array. By changing the relative positions of two turbines in the double turbine array to simulate the arrangement of different turbines, the hydrodynamic interference law between the turbines in the array and the influence of relative positions on the hydrodynamic characteristics in the turbine array are explored. The manner in which the turbines impact each other, the degree of influence, and rules for turbine array arrangement for maximum efficiency of the array will be discussed. The results of this study will provide technical insights to relevant researchers.

Description: Water, Vol. 10, Pages 1241: Mathematical Modeling of Ice Dynamics as a Decision Support Tool in River Engineering Water doi: 10.3390/w10091241 Authors: Tomasz Kolerski The prediction of winter flooding is a complicated task since it is affected by many meteorological and hydraulic factors. Typically, information on river ice conditions is based on historical observations, which are usually incomplete. Recently, data have been supplemented by information extracted from satellite images. All the above mentioned factors provide a good background of the characteristics of ice processes, but are not sufficient for a detailed analysis of river ice, which is highly dynamic and has a local extent. The main aim of this paper is to show the possibility of the prediction of ice jams in a river using a mathematical model. The case of the Odra River was used here. Within the Lower and Middle Odra River, the most significant flood risk, in winter conditions, is posed by ice jams created when movable ice is stopped by existing obstacles such as shallow areas in the riverbed, the narrowing of the riverbed, and other obstacles caused as a result of sudden changes of the river current, backwater from sea waters, and north winds, which contribute to the creation of ice jams. This in turn causes the damming of water and flooding of adjacent areas. The DynaRICE model was implemented at two locations along the Odra River, previously selected as ice-prone areas. Also, a thermal simulation of ice cover formation on Lake Dąbie was shown with variable discharge. The results of numerical simulations showed a high risk of ice jamming on the Odra River, created within one day of ice moving downstream. The prediction of the place and timing, as well as the extent, of the ice jam is impossible without the application of a robust mathematical model.

Description: Water, Vol. 10, Pages 1239: Sewer Condition Prediction and Analysis of Explanatory Factors Water doi: 10.3390/w10091239 Authors: Tuija Laakso Teemu Kokkonen Ilkka Mellin Riku Vahala Sewer condition is commonly assessed using closed-circuit television (CCTV) inspections. In this paper, we combine inspection results, pipe attributes, network data, and data on pipe environment to predict pipe condition and to discover which factors affect it. We apply the random forest algorithm to model pipe condition and assess the variable importance using the Boruta algorithm. We analyse the impact of predictor variables on poor condition using partial dependence plots, which are a valuable technique for this purpose. The results can be used in screening pipes for future inspections and provide insight into the dynamics between predictor variables and poor condition.

Description: Water, Vol. 10, Pages 1238: Insight into the Degradation of Two Benzophenone-Type UV Filters by the UV/H2O2 Advanced Oxidation Process Water doi: 10.3390/w10091238 Authors: Erdeng Du Jiaqi Li Siqi Zhou Miao Li Xiang Liu Huajie Li Environmental problems caused by UV filters, a group of emerging contaminants, have attracted much attention. The removal of two typical UV filters benzophenone (BP) and 4,4′-dihydroxy-benzophenone (HBP) in water was investigated by the UV/H2O2 process. The response surface methodology (RSM) and central composite design (CCD) were applied to investigate the effects of the process parameters on the degradation rate constants, including the initial contaminant concentration, H2O2 dose, and UV light intensity. BP is more easily degraded by the UV/H2O2 process. Both processes followed pseudo-first-order kinetics. The results obtained with the built RSM model are in accordance with the experimental results (adjusted coefficients R2(adj)= 0.9835 and 0.9778 for BP and HBP, respectively). For both processes, the initial contaminant concentration (exerting a negative effect) were the most important factors controlling the degradation, followed by H2O2 dose and UV intensity (exerting positive effects). A total of 15 BP degradation products and 13 HBP degradation products during the UV/H2O2 process were identified by LC/MS and GC/MS. A series of OH radical irritated reactions, including hydroxylation, carboxylation, and ring cleavage, led to the final degradation of BP and HBP. Degradation pathways of BP and HBP were also proposed. On the whole, this work is a unique contribution to the systematic elucidation of BP and HBP degradation by the UV/H2O2 process.

Description: Water, Vol. 10, Pages 1240: Potential Impacts of Induced Bank Filtration on Surface Water Quality: A Conceptual Framework for Future Research Water doi: 10.3390/w10091240 Authors: Mikael Gillefalk Gudrun Massmann Gunnar Nützmann Sabine Hilt Studies on induced bank filtration (IBF), a cost-effective and reliable drinking water production method, usually focus on processes affecting the target drinking water quality. We aim to expand this view by assessing potential impacts of IBF on surface water quality. We suggest that IBF can directly and indirectly affect several physical, chemical and biological processes in both the sediment and open water column, eventually leading to positive or negative changes in source water quality. Direct effects of IBF comprise water level fluctuations, changes in water level and retention time, and in organic content and redox conditions in littoral sediments. Indirect effects are mainly triggered by interrupting groundwater discharge into the surface water body. The latter may result in increased seasonal temperature variations in sediment and water and reduced discharge of solutes transported by groundwater such as nutrients and carbon dioxide. These changes can have cascading effects on various water quality, e.g., by facilitating toxic phytoplankton blooms. We propose investigating these potential effects of IBF in future field and laboratory studies to allow for more detailed insights into these yet unknown effects and their magnitude in order to assure a sustainable application of this valuable technique in the future.

Description: Water, Vol. 10, Pages 1237: Evaluating Equity and Inclusion in Access to Water and Sanitation for Persons Living with HIV/AIDS in Wukro, Ethiopia Water doi: 10.3390/w10091237 Authors: Ruben Jimenez-Redal Natalie Holowko Jabier Almandoz Javier Soriano Francisco Arregui Francesc Magrinya For more than a decade, foreign aid-supported water interventions focusing on an increase in household private connections have been implemented in the small urban center of Wukro. However, little has been investigated about the effectiveness of these interventions in achieving equitable and inclusive access to water and sanitation for all, including the most vulnerable. With this purpose, a cross-sectional comparative analysis of service provision between the HIV-infected population (n = 199) and non-infected population (n = 199) was undertaken. Findings suggest significant inequalities regarding the primary water source, monthly expenditure in water, water consumption, and time employed to fetch water, as well as the type of toilet facility, number of users, and the time employed to access it. Results also show a reported feeling of discrimination with regard to service provision within the HIV-positive population. This study provides evidence on local-scale interventions increasing the number of household water connections but overlooking the pursuit of equity and inclusion for the most vulnerable. The study also presents recommendations on how to specifically target the needs of persons living with HIV/AIDS in order to achieve equitable and inclusive access to water and sanitation for all.

Description: Water, Vol. 10, Pages 1234: Evaluation of the Non-Darcy Effect of Water Inrush from Karst Collapse Columns by Means of a Nonlinear Flow Model Water doi: 10.3390/w10091234 Authors: Yi Xue Teng Teng Lin Zhu Mingming He Jie Ren Xun Dong Fei Liu Karst collapse columns (KCCs) are naturally formed geological structures that are widely observed in North China. Given their influence on normal mining operations and the progress of mining work, collapse columns pose a hidden danger in coal mining under the influence of manual mining. By communicating often with the aquifer, the water inrush from KCCs poses a serious threat to construction projects. This paper adopts three flow field models, namely, Darcy aquifer laminar flow, Forchheimer flow, and Navier–Stokes turbulent flow, based on the changes in the water inrush flow pattern in the aquifer and laneway, and uses COMSOL Multiphysics software to produce the numerical solutions of these models. As the water inrush flow velocity increases, the Forchheimer flow shows the effect of additional force (inertial resistance) on flow in KCCs, in addition to the effect of viscous resistance. After the joint action of viscous resistance and inertial resistance, the inertial resistance ultimately dominates and gradually changes the water inrush from the KCCs to fluid seepage. Forchheimer flow can comprehensively reflect the nonlinear flow process in the broken rock mass of KCCs, demonstrate the dynamic process from the Darcy aquifer to the final tunnel turbulence layer, and quantitatively show the changes in the flow patterns of the water inrush from KCCs.

Description: Water, Vol. 10, Pages 1236: Improving Reservoir Operation Criteria to Stabilize Water Supplies in a Multipurpose Dam: Focused on Nakdong River Basin in Korea Water doi: 10.3390/w10091236 Authors: Jungmin Kim Jinhyeog Park Suhyung Jang Hyungsan Kim Hyunwoong Kang Recently, torrential rain and drought have occurred in close temporal proximity and for similar durations due to changes in the spatiotemporal patterns of rainfall owing to climate change. In particular, when a drought occurs, it tends to be prolonged, making it necessary to improve the operation of multipurpose dams that not only control flooding but also serve as water supplies. In this study, standard water volume lines and action plans by response stage were improved so that water could be stored in advance of a drought instead of reservoir operation criteria set based on data from the past. The minimum water demand by use (domestic water, industrial water, and agricultural water) was also calculated. The improved reservoir operation criteria were applied to multipurpose dams in the Nakdong River Basin, and their effects were analyzed by calculating additionally secured water volumes. In the future, in case of lowered water volumes in multipurpose dams owing to a drought, the application of these improved reservoir operation criteria is expected to contribute to water supply stability by delaying entry into the drought stage and minimizing the damages caused by limited water supplies.

Description: Water, Vol. 10, Pages 1235: Regression Approaches for Hydrograph Separation: Implications for the Use of Discontinuous Electrical Conductivity Data Water doi: 10.3390/w10091235 Authors: Antonia Longobardi Paolo Villani Domenico Guida Albina Cuomo Understanding of runoff generation mechanisms affects the ability to manage streamflow quantity and quality issues. Concerning the baseflow in particular, measurements are almost never available and hydrograph separation is generally applied to characterize its relevant patterns. As an alternative to well-known recursive digital filters and mass balance filtering methods, this paper deals with the use of regression approaches, based on electrical conductivity measurements, as a proxy for total dissolved solids, to separate baseflow from total flow. Particular focus is placed on their flexibility and ability to adapt to discontinuous electrical conductivity data measurements. To illustrate this, we analyze a hydrochemical dataset collected from the Ciciriello experimental catchment (Southern Italy). The main findings are as follows: A comparative analysis suggests that the performance of regressive approaches in the case of daily electrical conductivity measurements is better than that of calibrated recursive digital filters. Weekly monitored electrical conductivity data led to performances comparable to the daily scale monitoring, and even monthly observation leads to a nonsignificant reduction in regression hydrograph filter performance; this shows how spot geochemical data monitoring may present valid and operational alternatives for characterization of baseflow in poorly gauged catchments.

Description: Water, Vol. 10, Pages 1254: A Novel Methodology for Multiple-Year Regulation of Reservoir Active Storage Capacity Water doi: 10.3390/w10091254 Authors: Panayotis C. Yannopoulos Alexander C. Demetracopoulos Reservoir design entails the determination of the required storage capacity over multiple years of low flow conditions to ensure the coverage of multiple-purpose water demands. Dam operation depends on many factors that may result in the decrease of required safe yields, leading to inadequate outflow supplies in the design period. This study addresses two issues: (a) the computation of reservoir active storage capacity performed with the aid of the new concept of a zero-height dam, a procedure easy to interpret physically and implement computationally; and (b) the generation of appropriate inflow data, provided that a substantial record of monthly inflows is available. The treatment of the inflow data for the generation of inflow sequences for any desired regulation period is performed by two original methods (First and Second), which are entirely different from other available methods and allow for the selection of a reservoir capacity with the desired level of exceedance probability. The two methods proposed give practically the same results. However, the Second Method, which generates inflow data consisting of hydrologic years with inflow values for each month randomly selected from the observed values for that month, is superior in terms of the ease with which inflow sequences are generated. Also, due to the large size of the random sample that can be generated, the exceedance probability curves are very smooth and allow for the easy selection of reservoir storage capacity with any level of desired exceedance probability. The proposed methodology may be useful for consultants and reservoir managers.

Description: Water, Vol. 10, Pages 1252: Investigating the Effects of Social Trust and Perceived Organizational Support on Irrigation Management Performance in Rural China Water doi: 10.3390/w10091252 Authors: Liu Yang Anthony Rezitis Yuchun Zhu Yang Ren Understanding the factors affecting irrigation management performance is crucial for sustainable resource use, especially with the decentralized management mode of irrigation systems being implemented in rural China. This paper contributes to the research field by incorporating different categories of social trust and perceived organization support (POS) into the analysis of irrigation management performance, by linking multiple elements that are based on the Institutional Analysis and Development (IAD) framework. We employed principal component analysis (PCA) and ordered probit regression to analyze a database covering 785 households in the upstream of the Yellow River basin. The results suggested that social trust and POS positively affected the irrigation management performance, and social trust strengthened the positive effect of POS on the performance. Furthermore, the results indicated that personal trust and institutional trust, as well as perceived emotional support and physical support, positively affected the performance. In addition, we also found that household characteristics, household cognition, group characteristics, physical conditions, and rules-in-use also had significant impact on the performance. This paper can be used to inform the government that social trust and POS need to be considered in the common-pool resources (CPRs) management.

Description: Water, Vol. 10, Pages 1251: A Hooked-Collar for Bridge Piers Protection: Flow Fields and Scour Water doi: 10.3390/w10091251 Authors: Su-Chin Chen Samkele Tfwala Tsung-Yuan Wu Hsun-Chuan Chan Hsien-Ter Chou A new type of collar, the hooked-collar, was studied through experiments and numerical methods. Tests were conducted using a hooked collar of a width of 1.25b and a height of 0.25b, where b is the bridge-pier width. The hooked-collar efficiency was evaluated by testing different hooked-collar placements within the bridge-pier, which were compared to the bridge-pier without any collar. A double hooked-collar configuration, one placed at the bed level and the other buried 0.25b, was the most efficient at reducing the scour hole. In other cases, a hooked-collar positioned 0.25b above the bed slightly reduced the scour hole and had similar scour patterns when compared to the pier without the hooked-collar. The flow fields along the vertical symmetrical plane in the experiments are also presented. Laboratory experiments and numerical tests show that maximal downflow is highly reduced along with a corresponding decrease in horseshoe vortex strength for the experiments with the hooked-collar, compared to cases without the hooked-collar. The flow fields reveal that the maximum turbulent kinetic energy decreases with the installation of the hooked-collar.

Description: Water, Vol. 10, Pages 1253: Evaporation from (Blue-)Green Roofs: Assessing the Benefits of a Storage and Capillary Irrigation System Based on Measurements and Modeling Water doi: 10.3390/w10091253 Authors: Dirk Gijsbert Cirkel Bernard R. Voortman Thijs van Veen Ruud P. Bartholomeus Worldwide cities are facing increasing temperatures due to climate change and increasing urban density. Green roofs are promoted as a climate adaptation measure to lower air temperatures and improve comfort in urban areas, especially during intensive dry and warm spells. However, there is much debate on the effectiveness of this measure, because of a lack of fundamental knowledge about evaporation from different green roof systems. In this study, we investigate the water and energy balance of different roof types on a rooftop in Amsterdam, the Netherlands. Based on lysimeter measurements and modeling, we compared the water and energy balance of a conventional green roof with blue-green roofs equipped with a novel storage and capillary irrigation system. The roofs were covered either with Sedum or by grasses and herbs. Our measurements and modeling showed that conventional green roof systems (i.e., a Sedum cover and a few centimeters of substrate) have a low evaporation rate and due to a rapid decline in available moisture, a minor cooling effect. Roofs equipped with a storage and capillary irrigation system showed a remarkably large evaporation rate for Sedum species behaving as C3 plants during hot, dry periods. Covered with grasses and herbs, the evaporation rate was even larger. Precipitation storage and capillary irrigation strongly reduced the number of days with dry-out events. Implementing these systems therefore could lead to better cooling efficiencies in cities.

Description: Water, Vol. 10, Pages 1249: Water Quality as an Indicator of Stream Restoration Effects—A Case Study of the Kwacza River Restoration Project Water doi: 10.3390/w10091249 Authors: Natalia Mrozińska Katarzyna Glińska-Lewczuk Paweł Burandt Szymon Kobus Wojciech Gotkiewicz Monika Szymańska Martyna Bąkowska Krystian Obolewski River restoration projects rely on environmental engineering solutions to improve the health of riparian ecosystems and restore their natural characteristics. The Kwacza River, the left tributary of the Słupia River in northern Poland, and the recipient of nutrients from an agriculturally used catchment area, was restored in 2007. The ecological status of the river’s biotope was improved with the use of various hydraulic structures, including palisades, groynes and stone islands, by protecting the banks with trunks, exposing a fragment of the river channel, and building a by-pass near a defunct culvert. The effects of restoration treatments were evaluated by comparing the physicochemical parameters of river water along the 2.5 km restored section between the source and the mouth to the Słupia, before restoration and 6 years after hydrotechnical treatments. A total of 18 physicochemical parameters were analyzed at 10 cross-sections along the river. The greatest changes were observed in the concentrations of NO3−-N and NH4+-N, which decreased by 70% and 50%, respectively. Dissolved oxygen concentration increased by 65%. Chloride values increased by 44%, and chlorophyll-a concentration increased by 30% after the project. The cut-off channel (by-pass), semi-palisades, and single groynes were the treatments that contributed most to water quality improvement. The results of this study indicate that river restoration projects can substantially reduce nitrogen pollution, which is particularly important in agricultural areas. Such measures can effectively reinstate natural conditions in river ecosystems. Hydrochemical monitoring is required to control the parameters of restored rivers.

Description: Water, Vol. 10, Pages 1250: Optimal Operation of Cascade Reservoirs for Flood Control of Multiple Areas Downstream: A Case Study in the Upper Yangtze River Basin Water doi: 10.3390/w10091250 Authors: Chao Zhou Na Sun Lu Chen Yi Ding Jianzhong Zhou Gang Zha Guanglei Luo Ling Dai Xin Yang The purpose of a flood control reservoir operation is to prevent flood damage downstream of the reservoir and the safety of the reservoir itself. When a single reservoir cannot provide enough storage capacity for certain flood control points downstream, cascade reservoirs should be operated together to protect these areas from flooding. In this study, for efficient use of the reservoir storage, an optimal flood control operation model of cascade reservoirs for certain flood control points downstream was proposed. In the proposed model, the upstream reservoirs with the optimal operation strategy were considered to reduce the inflow of the reservoir downstream. For a large river basin, the flood routing and time-lag cannot be neglected. So, dynamic programming (DP) combined with the progressive optimality algorithm (POA) method, DP-POA, was proposed. Thus, the innovation of this study is to propose a two-stage optimal reservoir operation model with a DP-POA algorithm to solve the problem of optimal co-operation of cascade reservoirs for multiple flood control points downstream during the flood season. The upper Yangtze River was selected as a case study. Three reservoirs from upstream to downstream, Xiluodu, Xiangjiaba and the Three Gorges reservoirs (TGR) in the upper Yangtze River, were taken into account. Results demonstrate that the two-stage optimization algorithm has a good performance in solving the cascade reservoirs optimization problem, because the inflow of reservoir downstream and the division volumes were largely reduced. After the optimal operation of Xiluodu and Xiangjiaba reservoirs, the average reduction of flood peak for all these 13 typical flood hydrographs (TFHs) is 13.6%. Meanwhile, the cascade reservoirs can also store much more storm water during a flood event, and the maximum volumes stored in those two reservoirs upstream in this study can reach 25.2 billion m3 during a flood event. Comprising the proposed method with the current operation method, results demonstrate that the flood diversion volumes at the flood control points along the river decrease significantly.

Description: Water, Vol. 10, Pages 1246: Coupling of Ultrasonic and Photometric Techniques for Synchronous Measurements of Unconfined Turbidity Currents Water doi: 10.3390/w10091246 Authors: Richard I. Wilson Heide Friedrich By synchronizing data collection, such as photometric and ultrasonic Doppler profiling (UVP) measurement techniques, new insights can be obtained into environmental flows, such as highly dynamic turbidity currents. We introduce a combined experimental setup, which ultimately allows a time reduction in testing programmes, and discuss the measurement advances with the help of four surface conditions we tested for unconfined turbidity currents: (a) a smooth surface; (b) a smooth surface with an obstacle present; (c) a rough surface; and (d) a rough surface with an obstacle present. We show that data from both measurement techniques indicate that a rough surface reduces global current velocities and the magnitude of turbidity current phenomena, including Kelvin-Helmholtz instabilities and lobe-and-cleft formation. However, by coupling the techniques, photometric data give valuable insight into the spatial development of instabilities, such as the grouping of lobe and cleft formations. The presence of an obstacle causes local regions of an increased and decreased velocity, but does not affect the global current velocity. Additionally, the obstacle created three local intensity maxima upstream, dissipating to two maxima downstream, supporting the presence of local eddies. The study shows that the combination of UVP and photometry is an effective way forward for obtaining detailed qualitative and quantitative insights into turbulent flow characteristics and we highlight the potential for future research.

Description: Water, Vol. 10, Pages 1242: Influence of Land and Water Rights on Land Degradation in Central Asia Water doi: 10.3390/w10091242 Authors: Ekaterina Strikeleva Iskandar Abdullaev Tais Reznikova Land degradation is a key issue for Central Asia as an agrarian region. Land degradation in Central Asia is usually seen as a technological challenge and corresponding solutions are associated with the improvement of land-use technology. However, the reality is more complicated and multi-faceted. Institutional aspects of land degradation in the region are more prominent and yet unnoticed. De-linked water and land rights, increased land production functions, water infrastructure degradation, a lack of water-use monitoring, and a lack of knowledge among water users constitute the major institutional aspects of land degradation in Central Asia. This paper looks at the linkages between water and land rights and the main aspects of land degradation. The research was built on a literature review, including internationally funded project reports and in-house investigations.

Description: Water, Vol. 10, Pages 1265: An Improved Grid-Xinanjiang Model and Its Application in the Jinshajiang Basin, China Water doi: 10.3390/w10091265 Authors: Changqing Meng Jianzhong Zhou Deyu Zhong Chao Wang Jun Guo A modified form of the distributed Grid-Xinanjiang model (GXAJ) characterizing the infiltration excess and saturation excess runoff mechanisms coupled to a two-source potential evapotranspiration model (TSPE) was proposed to simulate the hydrological process and study the spatiotemporal pattern of the precipitation, evapotranspiration, and soil moisture in the Jinshajiang River basin. In the flow routing module, the flow is routed by the physically nonlinear Muskingum–Cunge method. The TSPE model can calculate the spatiotemporal variation of the potential canopy transpiration (CT), interception evaporation (IE), and potential soil evaporation (SE). Subsequently, the calculated potential evapotranspiration (PE) is coupled to the GXAJ model to calculate the water budget in each grid. An a priori parameter estimation was developed to obtain the spatially varied parameters from geographical data, including digital elevation model (DEM) data, soil data, vegetation data, and routing data. Hydrometeorological data were interpolated to 4750 grids with cell sizes of 10 × 10 km by the Thiessen Polygon method. The DEM data was used to extract the flow direction, river length, hillslope, and channel slopes and to adjust the altitude-related meteorological variables. The reprocessed Moderate Resolution Imaging Spectroradiometer (MODIS) leaf area index (LAI) from the Beijing Normal University (BNU) dataset, which has a spatial resolution of 1 km × 1 km, was used to obtain the spatiotemporal variation in the LAI. The developed GXAJ model was applied to three sub-basins in the Jinshajiang River basin and was compared to the traditional GXAJ model. The developed GXAJ model satisfactorily reproduced the streamflow at each catchment outlet and matched the peak discharges better than the traditional GXAJ model for both the dry and wet seasons. The uneven distribution of the simulated mean annual evapotranspiration in the whole watershed was closely related to the vegetation types, ranging from 189.81 to 585.45 mm. Forest and woodland, shrubland, grassland, and cropland were shown to have mean annual evapotranspiration values of 485.6, 289.4, 275.9, and 392.3 mm, respectively. The ratios of the annual evapotranspiration to precipitation (E/P) of the forest, woodland, shrubland, grassland, and cropland were 54, 83, 53, and 48%, respectively.

Description: Water, Vol. 10, Pages 1264: Effect of Water Management Technology Used in Trout Culture on Water Quality in Fish Ponds Water doi: 10.3390/w10091264 Authors: Marcin Sidoruk Ireneusz Cymes Pond management requires that a specific fish culture is conducted while taking into account both production possibilities and profitability, as well as the impact it may have on the natural environment. This study aimed to evaluate the effect of three water management systems used in rainbow trout culture on water quality in fish ponds. It was conducted at six trout farms and differing in water management strategy. After water had flown through the fishing ponds, its quality was significantly less impaired at farms operating in the flow and cascade systems. In turn, waters discharged from farms using the recirculation system were characterized by the poorest quality and lowest values on the Water Quality Index (WQI). It was found that the flow and cascade systems can be used to maintain the water quality and give less fish mortality for trout. It has been shown that the use of a water recirculation system in rainbow trout cultures significantly affects the quality of water in fishponds and can potentially lead to suppression of fish resistance and in extreme cases, to fish death. This study will help fish farmers in choosing the optimal variant of water management, taking into account both the best fish health with the least negative impact of fish farms on the environment.

Description: Water, Vol. 10, Pages 1267: Irrigation Management Based on Reservoir Operation with an Improved Weed Algorithm Water doi: 10.3390/w10091267 Authors: Mohammad Ehteram Vijay P. Singh Hojat Karami Khosrow Hosseini Mojgan Dianatikhah Md. Shabbir Hossain Chow Ming Fai Ahmed El-Shafie Water scarcity is a serious problem throughout the world. One critical part of this problem is supplying sufficient water to meet irrigation demands for agricultural production. The present study introduced an improved weed algorithm for reservoir operation with the aim of decreasing irrigation deficits. The Aswan High Dam, one of the most important dams in Egypt, was selected for this study to supply irrigation demands. The improved weed algorithm (IWA) had developed local search ability so that the exploration ability for the IWA increased and it could escape from local optima. Three inflows (low, medium and high) to the reservoir were considered for the downstream demands. For example, the average solution for the IWA at high inflow was 0.985 while it was 1.037, 1.040, 1.115 and 1.121 for the weed algorithm (WA), bat algorithm (BA), improved particle swarm optimization algorithm (IPSOA) and genetic algorithm (GA). This meant that the IWA decreased the objective function for high inflow by 5.01%, 5.20%, 11.65% and 12% compared to the WA, BA, IPSOA and GA, respectively. The computational time for the IWA at high inflow was 22 s, which was 12%, 18%, 24% and 29% lower than the WA, BA, IPSOA and GA, respectively. Results indicated that the IWA could meet the demands at all three inflows. The reliability index for the IWA for the three inflows was greater than the WA, BA, IPSOA and GA, meaning that the released water based on IWA could well supply the downstream demands. Thus, the improved weed algorithm is suggested for solving complex problems in water resources management.

Description: Water, Vol. 10, Pages 1285: Maternal Environment Effect of Warming and Eutrophication on the Emergence of Curled Pondweed, Potamogeton crispus L. Water doi: 10.3390/w10091285 Authors: Chao Li Tao Wang Min Zhang Jun Xu Maternal effects may play an important role in life history and offspring performance of aquatic plants. Performance and response of maternal and offspring aquatic plants can affect population dynamics and community composition. Understanding maternal effect can help to fill a gap in the knowledge of aquatic plant life cycles, and provide important insights for species’ responses to climate change and eutrophication. This study showed that maternal warming and eutrophication significantly affected the early life stages of curled pondweed, Potamogeton crispus, a submerged macrophyte. Propagule in warmed condition had higher germination percentages and a shorter mean germination time than those under ambient conditions. However, propagule germination in phosphorus addition treatment was inhibited due to the negative effect of eutrophication, e.g., phytoplankton competition and deteriorated underwater light. Meanwhile, elevated temperature led to a decrease of total nitrogen concentrations and an increase of carbon: nitrogen ratios in plant tissues, which may suggest that P. crispus will allocate more nutrients to propagules in order to resist the adverse effects of high temperature. A subsequent germination experiment in the same ambient condition showed that maternal warming promoted seedling emergence in contrast to maternal phosphorus addition. Consequently, global warming could modify population growth via maternal environmental effects on early life histories, while increased anthropogenic nutrient inputs may result in a decreased submerged macrophyte. These maternal effects on offspring performance may change competition and the survival of early life-history stages under climate warming and eutrophication through changing the ecological stoichiometry of plant tissue.

Description: Water, Vol. 10, Pages 1284: Thermal and Hydrodynamic Changes under a Warmer Climate in a Variably Stratified Hypereutrophic Reservoir Water doi: 10.3390/w10091284 Authors: Raymond Mark Lee Trent Wade Biggs Xing Fang We quantified effects of future climate warming on temperature and stability in a variably stratified, hypereutrophic reservoir with large fluctuations in water level by calibrating a 2-D model (CE-QUAL-W2, version 3.7.1, Portland State University, Portland, USA) of reservoir hydrodynamics using a time series (1992 to 2011) of inflow and air and water temperature. The model was then forced with increased air temperature projected by an ensemble of climate models that accounted for complex local topography and seasonality, with greater warming in summer. Warming increased annual evaporation rates by 2.6 to 7.9%. Water temperature increased by 0.44 (whole-reservoir; p < 0.05), 0.47 (epilimnion; p < 0.01), and 0.30 °C (hypolimnion; p < 0.05) per 1 °C increase in air temperature. Thickness of the epilimnion and hypolimnion diminished, with expansion of the metalimnion. Schmidt stability correlated with mean water depth over a wide range of depths (3.9 to 8.1 m; Adj. R2 = 0.91 to 0.93; p < 0.001). Increased air temperature increased mean annual stability by 6.1 to 23.6 J m−2 when depth was large and the reservoir stratified, but when depth was low (due to combined low inflow and, in preceding years, high withdrawals), inhibiting stratification, then water temperatures increased evenly (and more) throughout the vertical profile so change in mean annual stability was near zero (−0.1 to 1.1 J m−2). Combined effects of reservoir management (volume, timing, and elevation of water withdrawal) and climate warming (temperature of air and benthic sediment) can impact the hydrodynamic regime differently under variably stratified conditions with implications for release of phosphorus from sediment and vertical transport of phosphorus to the euphotic zone.

Description: Water, Vol. 10, Pages 1282: How Environmental Protection Motivation Influences on Residents’ Recycled Water Reuse Behaviors: A Case Study in Xi’an City Water doi: 10.3390/w10091282 Authors: Xiaojun Liu Yuqi He Hanliang Fu Baiyu Chen Mengmeng Wang Zelin Wang Pro-environmental behaviors related to reclaimed water reuse are regarded as important motivations for both environmental protection and the use of reclaimed water, and these motivations could affect the citizens’ decision whether they will accept reclaimed water reuse. A hypothesis model was developed as the NAM (Norm Activation Model) has changed, and this hypothesis model was used to explore the factors that affect the citizen’s decision about the reclaimed water reuse, and obtain a better understanding of the mechanism of urban citizens in environmental protection and the related outcomes. First, 584 samples were used to verify the reliability and validity of data, and AMOS21.0 was used to test the goodness-of-fit between the sample data and the hypothesis model. Based on this, the applicability of the improved NAM was verified through the study of recycled water reuse. The hypothesis model was used to analyze its direct influences, showing that environmental motivation has positive influences on the citizens’ acceptance toward recycled water reuse. Besides, Bootstrap method was used to verify the mediation effect, proving that awareness of consequences regarding environmental pollution caused by human activities and ascription of responsibility could strengthen the citizens’ motivation to protect the environment.

Description: Water, Vol. 10, Pages 1281: Irrigation Canal System Delivery Scheduling Based on a Particle Swarm Optimization Algorithm Water doi: 10.3390/w10091281 Authors: Ye Liu Ting Yang Rong-Heng Zhao Yi-Bo Li Wen-Ju Zhao Xiao-Yi Ma Reasonable planning of water delivery schedules for canal systems can reduce losses caused by water seepage and improve the utilization efficiency of irrigation water. Empirical methods of water delivery scheduling for canal systems usually cause problems such as insufficient discharge, excessively delayed water delivery, and large losses under given water requirements. In this study, a canal water delivery scheduling model was set up, and a customized algorithm based on particle swarm optimization was proposed. Typical heuristic algorithms often become trapped in local optima and often search inefficiently under numerous constraints; however, the proposed algorithm can overcome these typical problems. The proposed method was evaluated for two typical canal irrigation systems, and the results showed that the algorithm is robust and efficient and can quickly meet the water delivery optimization schedules for canal irrigation systems. Compared with empirical methods, the algorithm reduced the leakage loss of delivered water from 7.29% to 5.40%, and 8.97% to 7.46% for the two tested canal systems. The discharge of the main canal is relatively stable, which can reduce the difficulty of head gate adjustment. The proposed optimization algorithm can provide practical and efficient water delivery schedules for irrigation canal systems.

Description: Water, Vol. 10, Pages 1283: Building ANN-Based Regional Multi-Step-Ahead Flood Inundation Forecast Models Water doi: 10.3390/w10091283 Authors: Li-Chiu Chang Mohd Zaki M. Amin Shun-Nien Yang Fi-John Chang A regional inundation early warning system is crucial to alleviating flood risks and reducing loss of life and property. This study aims to provide real-time multi-step-ahead forecasting of flood inundation maps during storm events for flood early warnings in inundation-prone regions. For decades, the Kemaman River Basin, located on the east coast of the West Malaysia Peninsular, has suffered from monsoon floods that have caused serious damage. The downstream region with an area of approximately 100 km2 located on the east side of this basin is selected as the study area. We explore and implement a hybrid ANN-based regional flood inundation forecast system in the study area. The system combines two popular artificial neural networks—the self-organizing map (SOM) and the recurrent nonlinear autoregressive with exogenous inputs (RNARX)—to sequentially produce regional flood inundation maps during storm events. The results show that: (1) the 4 × 4 SOM network can effectively cluster regional inundation depths; (2) RNARX networks can accurately forecast the long-term (3–12 h) regional average inundation depths; and (3) the hybrid models can produce adequate real-time regional flood inundation maps. The proposed ANN-based model was shown to very quickly carry out multi-step-ahead forecasting of area-wide inundation depths with sufficient lead time (up to 12 h) and can visualize the forecasted results on Google Earth using user devices to help decision makers and residents take precautionary measures against flooding.

Description: Water, Vol. 10, Pages 1280: Interval Multi-Attribute Decision of Watershed Ecological Compensation Schemes Based on Projection Pursuit Cluster Water doi: 10.3390/w10091280 Authors: Zhang Zhou Zhou The ecological compensation scheme of water pollution in the basin is a result of the interplay between upstream and downstream cities, which is of great significance to the guidance of regional economic development. The purpose of this paper is to propose a multi-attribute scheme decision algorithm, which is expressed in the form of interval number, to reduce the uncertainty of decision results and improve the reliability of decision results. This method first uses the Monte Carlo simulation technique to produce a large number of random samples in the various attributes of the decision matrix to construct the random decision-making matrix (DMM). Then, according to the overall dispersion and local concentration of the random DMM, the clustering method of the projection pursuit is adopted. By accelerating the genetic algorithm, the weight and the best projection eigenvalues of each scheme are optimized, and the sorting results of the decision-making cases are obtained based on the projected eigenvalues. The results of the case study show that the uncertainty of the decision results is greater when the number of random simulations is very low; as the number of random simulations increases, the result of the decision becomes more and more stable and clear, and the uncertainty decreases. The results of the Duncan test show that, scheme 2, which is composed of financial compensation and remote development, is better than other schemes, and the decision making is more reasonable. The result of this decision has certain values for the ecological compensation scheme in Suzhou and Jiaxing cities, and the proposed method can be applied in similar range multi-attribute scheme decision-making issues.

Description: Water, Vol. 10, Pages 1278: Framework for WASH Sector Data Improvements in Data-Poor Environments, Applied to Accra, Ghana Water doi: 10.3390/w10091278 Authors: Rembrandt H. E. M. Koppelaar May N. Sule Zoltán Kis Foster K. Mensah Xiaonan Wang Charalampos Triantafyllidis Koen H. van Dam Nilay Shah Improvements in water, sanitation and hygiene (WASH) service provision are hampered by limited open data availability. This paper presents a data integration framework, collects the data and develops a material flow model, which aids data-based policy and infrastructure development for the WASH sector. This model provides a robust quantitative mapping of the complete anthropogenic WASH flow-cycle: from raw water intake to water use, wastewater and excreta generation, discharge and treatment. This approach integrates various available sources using a process-chain bottom-up engineering approach to improve the quality of WASH planning. The data integration framework and the modelling methodology are applied to the Greater Accra Metropolitan Area (GAMA), Ghana. The highest level of understanding of the GAMA WASH sector is achieved, promoting scenario testing for future WASH developments. The results show 96% of the population had access to improved safe water in 2010 if sachet and bottled water was included, but only 67% if excluded. Additionally, 66% of 338,000 m3 per day of generated wastewater is unsafely disposed locally, with 23% entering open drains, and 11% sewage pipes, indicating poor sanitation coverage. Total treated wastewater is <0.5% in 2014, with only 18% of 43,000 m3 per day treatment capacity operational. The combined data sets are made available to support research and sustainable development activities.

Description: Water, Vol. 10, Pages 1275: A Novel System for Water Disinfection with UV Radiation Water doi: 10.3390/w10091275 Authors: Bassam A. Younis Laura Mahoney Nicholas Palomo We present a novel system for water disinfection with ultra-violet (UV) radiation. In this system, the UV lamps do not come into contact with the water and hence remain free of fouling. The system incorporates a diffusor and a nozzle, with stationary guide vanes built into each. Their combined purpose is to reduce the hydraulic losses while imparting a strong swirl component to the flow. The swirl significantly enhances turbulent mixing processes and provides a self-cleansing mechanism that renders the system tolerant to high levels of turbidity and scaling. The hydrodynamic performance of the system was optimized using Computational Fluid Dynamics, while the manufacture of its key components was accomplished using advanced mechanical design software and three-dimensional (3D) printing. Biodosimetry testing with the bacteriophage MS2 indicated the delivery of a UV dose of 215.6 mJ/cm2. This produced a 6.9 log10 reduction of E. coli and 7.12 log10 reduction of MS2. Assessment of the system with hard water containing high Ca, Mg, and Fe concentrations, and with water with turbidity of 18 NTU indicated that the log10 removal of E. coli remained above 5.

Description: Water, Vol. 10, Pages 1276: Diurnal and Semidiurnal Cyclicity of Radon (222Rn) in Groundwater, Giardino Spring, Central Apennines, Italy Water doi: 10.3390/w10091276 Authors: Marino Domenico Barberio Francesca Gori Maurizio Barbieri Andrea Billi Roberto Devoti Carlo Doglioni Marco Petitta Federica Riguzzi Sergio Rusi Understanding natural variations of Rn (222Rn) concentrations is the fundamental prerequisite of using this radioactive gas as a tracer, or even precursor, of natural processes, including earthquakes. In this work, Rn concentrations in groundwater were continuously measured over a seven-month period, during 2017, in the Giardino Spring, Italy, together with groundwater levels in a nearby well installed into a fractured regional aquifer. Data were processed to reduce noise, and then analyzed to produce the Fourier spectra of Rn concentrations and groundwater levels. These spectra were compared with the spectrum of tidal forces. Results showed that diurnal and semidiurnal cycles of Rn concentrations, and filtered oscillations of groundwater levels, in the nearby well, are correlated with solar and luni-solar components of tidal forces, and suggested no correlation with the principal lunar components. Therefore, influencing factors linked to solar cycles, such as daily oscillations of temperature and atmospheric pressure, and related rock deformations, may have played a role in Rn concentrations and groundwater levels. An open question remains regarding the correlation, which is documented elsewhere, of Rn concentrations and groundwater levels with the lunar components of the solid Earth tides.

Description: Water, Vol. 10, Pages 1277: Detecting the Dominant Cause of Streamflow Decline in the Loess Plateau of China Based onthe Latest Budyko Equation Water doi: 10.3390/w10091277 Authors: Jing Zhao Shengzhi Huang Qiang Huang Hao Wang Guoyong Leng Quantifying the relative contributions of climate variability and human activity to streamflow change is important for effective water resource use and management. Four sub-catchments of the Wei River Basin (WRB) in the Loess Plateau in China were selected as the study region, where the evolution of parameter α from the latest Budyko equation (Wang-Tang equation) was explored using an 11-year moving window. The elasticity of streamflow was derived from the climatic aridity index, represented by the ratio of annual potential evaporation ( E P ) to annual precipitation ( P ), and catchment characteristics as represented by α . The effects of climate change and human activities on streamflow change during 1971–2010 were quantified with climate elasticity and decomposition methods. The contributions of different types of human activities to streamflow were further empirically determined using the water and soil conservation method. Results indicate that (1) under the same climate condition ( P and E P ), a higher value of α caused an increase in evaporation rate ( E / P ) and a decrease in runoff. Changes in these hydrological variables led to a subsequent reduction in streamflow in the WRB; (2) The absolute value of the precipitation elasticity was larger than the potential evaporation elasticity, indicating that streamflow change was more sensitive to precipitation; (3) The results based on the two methods were consistent. Climate change and human activities contributed to the decrease in streamflow by 29% and 71%, respectively, suggesting that human activities have exerted more profound impacts on streamflow in the study region; (4) Contributions of different water and soil conservation measures to streamflow reduction were calculated and sorted in descending order: Irrigation, industrial and domestic consumption, terrace, afforestation, reservoirs, check-dams, then grass-planting.

Description: Water, Vol. 10, Pages 1270: A Systematic Operation Program of a Hydropower Plant Based on Minimizing the Principal Stress: Haditha Dam Case Study Water doi: 10.3390/w10091270 Authors: Jing Li Ameen Mohammed Salih Ameen Thamer Ahmad Mohammad Nadhir Al-Ansari Zaher Mundher Yaseen Dam operation and management have become more complex recently because of the need for considering hydraulic structure sustainability and environmental protect on. An Earthfill dam that includes a powerhouse system is considered as a significant multipurpose hydraulic structure. Understanding the effects of running hydropower plant turbines on the dam body is one of the major safety concerns for earthfill dams. In this research, dynamic analysis of earthfill dam, integrated with a hydropower plant system containing six vertical Kaplan turbines (i.e., Haditha dam), is investigated. In the first stage of the study, ANSYS-CFX was used to represent one vertical Kaplan turbine unit by designing a three-dimensional (3-D) finite element (FE) model. This model was used to differentiate between the effect of turbine units’ operation on dam stability in accordance to maximum and minimum reservoir upstream water levels, and the varying flowrates in a fully open gate condition. In the second stage of the analysis, an ANSYS-static modeling approach was used to develop a 3-D FE earthfill dam model. The water pressure pattern determined on the boundary of the running turbine model is transformed into the pressure at the common area of the dam body with turbines. The model is inspected for maximum and minimum upstream water levels. Findings indicate that the water stress fluctuations on the dam body are proportional to the inverse distance from the turbine region. Also, it was found that the cone and outlet of the hydropower turbine system are the most affected regions when turbine is running. Based on the attained results, a systematic operation program was proposed in order to control the running hydropower plant with minimized principal stress at selected nodes on the dam model and the six turbines.

Description: Water, Vol. 10, Pages 1272: Collapsing Mechanisms of the Typical Cohesive Riverbank along the Ningxia–Inner Mongolia Catchment Water doi: 10.3390/w10091272 Authors: Guosheng Duan Anping Shu Matteo Rubinato Shu Wang Fuyang Zhu As one of the major sediment sources in rivers, bank collapse often occurs in the Ningxia–Inner Mongolia catchment and, to date, it caused substantial social, economic and environmental problems in both local areas and downstream locations. To provide a better understanding of this phenomenon, this study consisted of modifying the existing Bank Stability and Toe Erosion Model (BSTEM), commonly used to investigate similar phenomena, introducing new assumptions and demonstrating its applicability by comparing numerical results obtained against field data recorded at six gauging stations (Qingtongxia, Shizuishan, Bayan Gol, Sanhuhekou, Zhaojunfen, and Toudaoguai). Furthermore, the impact of multiple factors typical of flood and dry seasons on the collapse rate was investigated, and insights obtained should be taken into consideration when completing future projects of river adaptation and river restoration.

Description: Water, Vol. 10, Pages 1269: Preliminary Study of Computational Time Steps in a Physically Based Distributed Rainfall–Runoff Model Water doi: 10.3390/w10091269 Authors: Yun Seok Choi Mun-Ju Shin Kyung Tak Kim The choice of the computational time step (dt) value and the method for setting dt can have a bearing on the accuracy and performance of a simulation, and this effect has not been comprehensively researched across different simulation conditions. In this study, the effects of the fixed time step (FTS) method and the automatic time step (ATS) method on the simulated runoff of a distributed rainfall–runoff model were compared. The results revealed that the ATS method had less peak flow variability than the FTS method for the virtual catchment. In the FTS method, the difference in time step had more impact on the runoff simulation results than the other factors such as differences in the amount of rainfall, the density of the stream network, or the spatial resolution of the input data. Different optimal parameter values according to the computational time step were found when FTS and ATS were used in a real catchment, and the changes in the optimal parameter values were smaller in ATS than in FTS. The results of our analyses can help to yield reliable runoff simulation results.

Description: Water, Vol. 10, Pages 1273: Trend and Change-Point Analysis of Streamflow and Sediment Discharge of the Gongshui River in China during the Last 60 Years Water doi: 10.3390/w10091273 Authors: Li-Ping Guo Qiang Yu Peng Gao Xiao-Fei Nie Kai-Tao Liao Xiu-Long Chen Jian-Min Hu Xing-Min Mu The Gongshui River basin exhibits one of the most serious soil erosion areas in southern China, and has always been the key control area of national soil and water conservation programs. This study used daily precipitation, streamflow, and sediment concentration data collected from 1957 to 2015 from the main hydrological stations of the Gongshui River to investigate streamflow and sediment discharge variations and their responses to precipitation and human activities. The Mann-Kendall and Pettitt’s test were used for trend and change-point detection. The double mass curve (DMC) method was employed to quantify the effects of precipitation change and human activities on hydrological regime shifts. The results showed insignificant trends of both annual precipitation and streamflow for all stations, while the sediment discharge of most stations exhibited significant decreasing trends. Change-point analyses revealed that all hydrologic stations except Mazhou had transition years. The estimation via DMC indicated that after the change point years, there was a rapid reduction in sediment discharge at Hanlinqiao, Fengkeng, Julongtan, Xiashan, and Chawu stations, but not at Mazhou, Ruijin, and Yangxinjian stations. Human activity provided a significantly greater contribution to sediment discharge than precipitation. The evidence clearly indicates that the degree and extension of conservation or destruction measures and the construction of large- and medium-sized reservoirs were the major factors significantly decreasing or increasing annual sediment discharge of the Gongshui River. This work could serve as the basis for decision making regarding river basin water resources management to estimate the effects of anthropogenic impacts on water and sediment discharge variations during the last few decades, thereby guiding adaptation and protection of the water resources of the Gongshui River flowing into the Poyang Lake.

Description: Water, Vol. 10, Pages 1274: Developing Hydro-Meteorological Thresholds for Shallow Landslide Initiation and Early Warning Water doi: 10.3390/w10091274 Authors: Benjamin B. Mirus Michael D. Morphew Joel B. Smith Consistent relations between shallow landslide initiation and associated rainfall characteristics remain difficult to identify, due largely to the complex hydrological and geological processes causing slopes to be predisposed to failure and those processes that subsequently trigger failures. Considering the importance of hillslope hydrology for rainfall-induced landsliding, we develop and test a method for identifying hybrid hydro-meteorological thresholds to assess landslide initiation potential. We outline a series of steps for using a landslide inventory in combination with triggering rainfall and antecedent wetness to identify empirical thresholds that can inform landslide early warning systems. The method is semi-automated but remains flexible enough to allow threshold developers to consider data inputs and various performance metrics with different priorities for balancing failed versus false alarms. We demonstrate the utility of our approach for two monitoring sites near Seattle, Washington and in Portland, Oregon, USA, to develop daily bilinear thresholds within a two-dimensional parameter space, which rely on accurate 24 h forecasts, measured recent rainfall and in situ soil saturation. Although there were no prior landslide thresholds for Portland, our new hybrid threshold for the Seattle area outperforms established rainfall-only thresholds for the same region. Introducing subsurface hydrologic monitoring into landslide initiation thresholds has the potential to greatly improve early warning capabilities and help reduce losses.

Description: Water, Vol. 10, Pages 1290: The Effect of Bedrock Topography on Timing and Location of Landslide Initiation Using the Local Factor of Safety Concept Water doi: 10.3390/w10101290 Authors: Shirin Moradi Johan Alexander Huisman Holger Class Harry Vereecken Bedrock topography is known to affect subsurface water flow and thus the spatial distribution of pore water pressure, which is a key factor for determining slope stability. Therefore, the aim of this study is to investigate the effect of bedrock topography on the timing and location of landslide initiation using 2D and 3D simulations with a hydromechanical model and the Local Factor of Safety (LFS) method. A set of synthetic modeling experiments was performed where water flow and slope stability were simulated for 2D and 3D slopes with layers of variable thickness and hydraulic parameters. In particular, the spatial and temporal development of water content, pore water pressure, and the resulting LFS were analyzed. The results showed that the consideration of variable bedrock topography can have a significant effect on slope stability and that this effect is highly dependent on the intensity of the event rainfall. In addition, it was found that the consideration of 3D water flow may either increase or decrease the predicted stability depending on how bedrock topography affected the redistribution of infiltrated water.

Description: Water, Vol. 10, Pages 1291: Optimization Model for Agricultural Reclaimed Water Allocation Using Mixed-Integer Nonlinear Programming Water doi: 10.3390/w10101291 Authors: Ahmed A. Aljanabi Larry W. Mays Peter Fox Reclaimed water (RW) is a reliable alternative water supply for irrigation in the agricultural sector, which is the predominant consumer of water in Iraq. A mixed-integer nonlinear programming reclaimed water allocation optimization model was developed to maximize the net benefit generated from the cultivation of different types of crops, comparing the use of reclaimed water type A (tertiary treated water), and reclaimed water type B (secondary treated water). The model was solved using the Algorithms for coNTinuous/Integer Global Optimization of Nonlinear Equations (ANTIGONE) optimizer in the general algebraic modeling system (GAMS). A total of 84 agricultural farms located on 5300 ha to the south of Baghdad, Iraq were available for irrigation with reclaimed water. Analysis considered varying quantities of available reclaimed water and different irrigation efficiencies (45–85%). The net benefits from using lower quantities of reclaimed water were similar for both types of reclaimed water, and the highest net benefit crop was cultivated on 384 ha. As the quantities of water increased, the amount of cultivated land increased and the net benefit per hectare decreased as the model required the cultivation of more crops with lower economic value. Irrigation with reclaimed water has potential to increase agricultural and economic activity adjacent to Baghdad.

Description: Water, Vol. 10, Pages 1292: Sub-Bankfull Flow Frequency versus Magnitude of Flood Events in Outlining Effective Discharges. Case Study: Trotuș River (Romania) Water doi: 10.3390/w10101292 Authors: Dan Dumitriu Effective discharge, which represents the flow, or range of flows, that transport the most sediment over the long-term, was determined based on the mean daily flow discharge and mean daily suspended sediment discharge recorded between 1994 and 2014 at four gauging stations along the Trotuș River. This study proposes an efficient method for the estimation of effective discharge based on observed values of the suspended sediment load. By employing this method the suspended sediment load is no longer either under- or overestimated as in the cases when the assessment is based on sediment rating curves. The assessment on effective discharge was performed at two distinct levels: for the entire data series during the investigated time spans and, subsequently, for flows less than the bankfull discharge. The effectiveness curves of the suspended sediment transport characteristics revealed highly multimodal characteristics with many peaks, indicating ample ranges for the effective discharges. The main effective discharge corresponded to large flood events, which are typical for the upper end of the discharge range, whereas the secondary effective discharges corresponded to sub-bankfull flows, which are more frequent. The changes that occurred in the channel bed are reflected by the temporal variations in the effective discharge.

Description: Water, Vol. 10, Pages 1288: Coupled Thermally-Enhanced Bioremediation and Renewable Energy Storage System: Conceptual Framework and Modeling Investigation Water doi: 10.3390/w10101288 Authors: Ali Moradi Kathleen M. Smits Jonathan O. Sharp This paper presents a novel method to couple an environmental bioremediation system with a subsurface renewable energy storage system. This method involves treating unsaturated contaminated soil using in-situ thermally enhanced bioremediation; the thermal system is powered by renewable energy. After remediation goals are achieved, the thermal system can then be used to store renewable energy in the form of heat in the subsurface for later use. This method can be used for enhanced treatment of environmental pollutants for which temperature is considered a limiting factor. For instance, this system can be used at a wide variety of petroleum-related sites that are likely contaminated with hydrocarbons such as oil refineries and facilities with above- and underground storage tanks. In this paper, a case-study example was analyzed using a previously developed numerical model of heat transfer in unsaturated soil. Results demonstrate that coupling energy storage and thermally-enhanced bioremediation systems offer an efficient and sustainable way to achieve desired temperature–moisture distribution in soil that will ultimately enhance the microbial activity.

Description: Water, Vol. 10, Pages 1287: Rheology of Un-Sieved Concentrated Domestic Slurry: A Wide Gap Approach Water doi: 10.3390/w10101287 Authors: Adithya Krishnan Thota Radhakrishnan Jules van Lier Francois Clemens Information on the rheology of domestic slurries is essential in designing pipeline transportation in novel sanitation systems. As concentrated slurries in their original collected state have wide particle size distribution, with particles up to 2 mm, a wide gap rheometer is used to acquire the rheograms. Rheograms obtained from a wide gap rheometer require a method to convert the rotational velocity to the shear rate, and this method must be robust to noisy data and yield stress in the slurry. For this purpose, a Tikhonov regularisation method is chosen as it suits the criteria the best. Using this, the rheograms are obtained for various total suspended solids (TSS) concentrations of slurries. A Herschel-Bulkley rheological model is used to represent the rheology of the slurries. The influence of the change in concentration of the slurries is represented through its influence on the Herschel-Bulkley parameters. The consistency index K exponentially increases with the concentration. The yield stress τ y , is 0 at low concentrations, and above 2.0% TSS (wt./wt.) exponentially increases with the concentration. The behaviour index n , is 1 at low concentrations, and above 2.6% TSS (wt./wt.) it decreases in an inverse power law with the concentration to reach a sort of plateau.

Description: Water, Vol. 10, Pages 1293: Assessment of Environmental Flows from Complexity to Parsimony—Lessons from Lesotho Water doi: 10.3390/w10101293 Authors: Aristoteles Tegos Wolfram Schlüter Niall Gibbons Yanis Katselis Andreas Efstratiadis Over the last decade, Environmental Flow Assessment (EFA) has focused scientific attention around heavily-modified hydrosystems, such as flow regulated releases downstream of dams. In this light, numerous approaches of varying complexity have been developed, the most holistic of which incorporate hydrological, hydraulic, biological and water quality inputs, as well as socioeconomic issues. Finding the optimal flow releases, informing policy and determining an operational framework are often the main focus. This work exhibits a simplification of the DRIFT framework, and is regarded as the first holistic EFA approach, consisting of three modules, namely hydrological, hydraulic and fish quality. A novel conceptual classification for fish quality is proposed, associating fish fauna requirements with hydraulic characteristics, exported by fish survey analyses. The new methodology was applied and validated successfully at three stream sites in Lesotho, where DRIFT was formerly employed.

Description: Water, Vol. 10, Pages 1299: Assessing the Impact of Site-Specific BMPs Using a Spatially Explicit, Field-Scale SWAT Model with Edge-of-Field and Tile Hydrology and Water-Quality Data in the Eagle Creek Watershed, Ohio Water doi: 10.3390/w10101299 Authors: Katherine R. Merriman Prasad Daggupati Raghavan Srinivasan Chad Toussant Amy M. Russell Brett Hayhurst The Eagle Creek watershed, a small subbasin (125 km2) within the Maumee River Basin, Ohio, was selected as a part of the Great Lakes Restoration Initiative (GLRI) “Priority Watersheds” program to evaluate the effectiveness of agricultural Best Management Practices (BMPs) funded through GLRI at the field and watershed scales. The location and quantity of BMPs were obtained from the U.S. Department of Agriculture-Natural Resources Conservation Service National Conservation Planning (NCP) database. A Soil and Water Assessment Tool (SWAT) model was built and calibrated for this predominantly agricultural Eagle Creek watershed, incorporating NCP BMPs and monitoring data at the watershed outlet, an edge-of-field (EOF), and tile monitoring sites. Input air temperature modifications were required to induce simulated tile flow to match monitoring data. Calibration heavily incorporated tile monitoring data to correctly proportion surface and subsurface flow, but calibration statistics were unsatisfactory at the EOF and tile monitoring sites. At the watershed outlet, satisfactory to very good calibration statistics were achieved over a 2-year calibration period, and satisfactory statistics were found in the 2-year validation period. SWAT fixes parameters controlling nutrients primarily at the watershed level; a refinement of these parameters at a smaller-scale could improve field-level calibration. Field-scale modeling results indicate that filter strips (FS) are the most effective single BMPs at reducing dissolved reactive phosphorus, and FS typically decreased sediment and nutrient yields when added to any other BMP or BMP combination. Cover crops were the most effective single, in-field practice by reducing nutrient loads over winter months. Watershed-scale results indicate BMPs can reduce sediment and nutrients, but reductions due to NCP BMPs in the Eagle Creek watershed for all water-quality constituents were less than 10%. Hypothetical scenarios simulated with increased BMP acreages indicate larger investments of the appropriate BMP or BMP combination can decrease watershed level loads.

Description: Water, Vol. 10, Pages 1300: Identifying Surface Runoff Pathways for Cost-Effective Mitigation of Pollutant Inputs to Drinking Water Reservoir Water doi: 10.3390/w10101300 Authors: Jolanta Dąbrowska Paweł B. Dąbek Iwona Lejcuś Surface runoff (overland flow) is the main element of the water cycle and is also crucial in the delivery of phosphorus and nitrogen from catchments to water bodies. Watercourses and reservoirs in agricultural catchments are particularly vulnerable to the delivery of biogenic compounds via surface runoff. Forested riparian buffers are considered effective in reducing nutrients and sediment loads in runoff from agricultural areas. Regrettably, the concentration of surface runoff may significantly limit the buffering capacity of vegetation strips, as channelised overland flow tends to avoid buffers without making optimal use of their ability to retain nutrients and sediment. The aim of the undertaken research was to delineate surface runoff pathways from surrounding areas to a drinking water reservoir as well as to identify potential concentration spots of overland flow. The research was conducted for the Dobromierz drinking water reservoir (GPS N: 50°54′27″, E: 16°14′37″). The reservoir is situated in a submountain catchment, where rainfall is an important factor taking part in driving diffuse P and N loads from land to water. Presented GIS-based method using high resolution Digital Terrain Model obtained from Light Detection and Ranging (LiDAR) allowed to determine areas with a tendency for high accumulation (concentration) of overland flow in the direct catchment of the reservoir. As main surface runoff areas, three sites each exceeding 100 ha were designated. The analysis of spatial data also allowed to establish the risk of agricultural diffuse pollution transfer via channelised overland flow to the reservoir from individual accumulation areas. It was found that in the forested part of the catchment (serving as a riparian buffer) there is no visible tendency for concentration of surface runoff, but simultaneously the vegetation strip does not prevent the transfer of runoff waters from agricultural areas through the privileged pathways of concentrated flow.

Description: Water, Vol. 10, Pages 1298: Denitrification-Potential Evaluation and Nitrate-Removal-Pathway Analysis of Aerobic Denitrifier Strain Marinobacter hydrocarbonoclasticus RAD-2 Water doi: 10.3390/w10101298 Authors: Dedong Kong Wenbing Li Yale Deng Yunjie Ruan Guangsuo Chen Jianhai Yu Fucheng Lin An aerobic denitrifier was isolated from a long-term poly (3-hydroxybutyrate-co-3-hydroxyvalerate) PHBV-supported denitrification reactor that operated under alternate aerobic/anoxic conditions. The strain was identified as Marinobacter hydrocarbonoclasticus RAD-2 based on 16S rRNA-sequence phylogenetic analysis. Morphology was observed by scanning electron microscopy (SEM), and phylogenetic characteristics were analyzed with the API 20NE test. Strain RAD-2 showed efficient aerobic denitrification ability when using NO3−-N or NO2−-N as its only nitrogen source, while heterotrophic nitrification was not detected. The average NO3−-N and NO2−-N removal rates were 6.47 mg/(L·h)and 6.32 mg/(L·h), respectively. Single-factor experiments indicated that a 5:10 C/N ratio, 25–40 °C temperature, and 100–150 rpm rotation speed were the optimal conditions for aerobic denitrification. Furthermore, the denitrifying gene napA had the highest expression on a transcriptional level, followed by the denitrifying genes nirS and nosZ. The norB gene was found to have significantly low expression during the experiment. Overall, great aerobic denitrification ability makes the RAD-2 strain a potential alternative in enhancing nitrate management for marine recirculating aquaculture system (RAS) practices.

Description: Water, Vol. 10, Pages 1302: Long-Term Suspended Sediment Concentrations and Loads from a Relatively Undisturbed Agroforested Catchment in the Northwest of the Iberian Peninsula Water doi: 10.3390/w10101302 Authors: M. Luz Rodríguez-Blanco M. Mercedes Taboada-Castro M. Teresa Taboada-Castro The suspended sediment dynamics in small catchments are difficult to estimate accurately because they result from the coupling of complex processes occurring at different scales. In this study, the dynamics of suspended sediment concentrations (SSC) and loads were assessed in an agroforested humid catchment in NW Spain, based on a long-term rainfall, discharge and suspended sediment dataset (12 hydrological years) from high-frequency monitoring. The results highlight the episodic nature of sediment transport in the study area, given that about 78% of SS was exported over 10% of the study period. The SS transport was related to runoff generation and flooding, although sediment availability also played an important role in SS transport. The SS load was mainly driven by high-magnitude rainfall events, while intense rainfall episodes generated high SSC peaks. The mean annual suspended sediment yield was relatively low from a quantitative stand point (10 Mg km−2 y−1); however, during 11% of the monitoring, SS concentrations exceeding the threshold threatened surface water quality (Freshwater Fish Directive 78/659/EEC and Directive 75/440/EEC), mainly during runoff events, indicating the need to adopt management practices in order to reduce or mitigate sediment loss during such episodes.

Description: Water, Vol. 10, Pages 1301: Evaluation of Hydraulic Performance Characteristics of a Newly Designed Dynamic Fluidic Sprinkler Water doi: 10.3390/w10101301 Authors: Xingye Zhu Alexander Fordjour Shouqi Yuan Frank Dwomoh Daoxing Ye A newly designed dynamic fluidic sprinkler was tested with different types of nozzles at different operating pressures. Therefore, the aim of this paper was to evaluate the hydraulic performance of a newly designed dynamic fluidic sprinkler. MATLAB R2014a software was employed to establish the computational program for the computed uniformity. Droplet sizes were determined using a Thies Clima Laser Precipitation Monitor. Results showed that the nozzle with a diameter of 5.5 mm gave the highest coefficient of uniformity value of 86% at a low pressure of 150 kPa. The comparison of water distribution profiles for the nozzle sizes (2, 3, 4, 5.5, 6 and 7 mm) at different operating pressures (100, 150, 200, 250 and 300 kPa) showed that a 5.5-mm nozzle size produced a parabola-shaped profile at 150 kPa. The mean droplet diameters for the nozzles sizes of 2, 3, 4, 5.5, 6 and 7 mm ranged from 0 to 4.2, 0 to 3.7, 0 to 3.6, 0 to 3.2, 0 to 0.5 and 0 to 3.8 mm, respectively. The comparison of droplet size distributions showed that 5.5 mm had the optimum droplet diameter of 3.2 mm. The largest droplet sizes had a maximum value of 4.0 for a 2-mm nozzle size. For all the nozzles sizes, 5.5 mm produced better results for hydraulic performance, which can significantly improve the performance and save water for crop production in sprinkler-irrigated fields.

Description: Water, Vol. 10, Pages 1296: Enumerating the Effects of Climate Change on Water Resources Using GCM Scenarios at the Xin’anjiang Watershed, China Water doi: 10.3390/w10101296 Authors: Muhammad Zaman Muhammad Naveed Anjum Muhammad Usman Ijaz Ahmad Muhammad Saifullah Shouqi Yuan Shiyin Liu The present study developed a novel approach to study the climate change impact on the water resources and generation of hydropower optimally using forecasted stream flows for the Xin’anjiang water shed in China. Future flows were projected using six large-scale Global circulation models (GCMs) with RCP4.5 and RCP8.5 scenarios. A newly developed mathematical modeling using particle swarm optimization was incorporated to work out the projected optimal electricity generation from the Xin’anjiang hydropower station. The results reveal that watershed will be warmer by the end of the 21st century with a maximum increase of up to 4.9 °C for mean maximum, and 4.8 °C for mean minimum temperature. Six GCMs under Representative Concentration pathways (RCPs) showed that future precipitation is complex to predict with certainty and significant differences were observed among the different GCMs. The overall mean monthly and seasonal precipitation increase for most scenarios with the maximum increase during the 2020s and 2080s, whereas 2050s exhibited the lesser increase. Resultantly, there would be an increase in the stream flows during these periods, which was used for electricity production up to 31.41 × 108 kW·h.

Description: Water, Vol. 10, Pages 1297: A Regional-Scale Landslide Warning System Based on 20 Years of Operational Experience Water doi: 10.3390/w10101297 Authors: Samuele Segoni Ascanio Rosi Riccardo Fanti Angela Gallucci Antonio Monni Nicola Casagli SIGMA is a regional landslide warning system based on statistical rainfall thresholds that operates in Emilia Romagna (Italy). In this work, we depict its birth and the continuous development process, still ongoing, after two decades of operational employ. Indeed, a constant work was carried out to gather and incorporate in the modeling new data (extended rainfall recordings, updated landslides inventories, temperature and soil moisture data). The use of these data allowed for regular updates of the model and some conceptual improvements, which consistently increased the forecasting effectiveness of the warning system through time. Landslide forecasting at regional scale is a very complex task, but this paper shows that, as time passes by, the systematic gathering and analysis of new data and the continuous progresses of research activity, uncertainties can be progressively reduced. Thus, by the setting up of forward-looking research programs, the performances and the reliability of regional scale warning systems can be increased with time.

Description: Water, Vol. 10, Pages 1310: Increasing Energy Efficiency in Water Collection Systems by Submersible PMSM Well Pumps Water doi: 10.3390/w10101310 Authors: Marcus Beck Alexander Sperlich Ricardo Blank Eckehard Meyer Ralf Binz Mathias Ernst Water collection based on groundwater abstraction has a high energy consumption that depends primarily on the operation and performance of submersible well pumps. The fact of the matter is that these machines still work with a global energy efficiency of less than 50%, and further investigations of the energy aspects in well pumps are needed. The present study introduces measures to increase the global efficiency of submersible well pumps linked to electrical energy savings. Common submersible pumps with asynchronous motors (ASMs) were compared with innovative permanent magnet synchronous motor (PMSM) technology in real well fields in Berlin and Hamburg waterworks. This study confirms that PMSM pumps showed a 6.8%-points higher global efficiency compared to ASM pumps at optimal working points. The investigation of the impact of well field operation on local pump efficiency offers an additional increase in the global efficiency. In this context, the influence of variable speed control on the global efficiency and the energy consumption was analyzed. Global efficiencies of over 70%, and potential energy savings of up to 20%, were determined for the speed-controlled PMSM pump. This offers water suppliers new incentives to optimize their water collection systems for less energy consumption.

Description: Water, Vol. 10, Pages 1311: Season-Dependent Hedging Policies for Reservoir Operation—A Comparison Study Water doi: 10.3390/w10101311 Authors: Nikhil Bhatia Roshan Srivastav Kasthrirengan Srinivasan During periods of significant water shortage or when drought is impending, it is customary to implement some kind of water supply reduction measures with a view to prevent the occurrence of severe shortages (vulnerability) in the near future. In the case of operation of a water supply reservoir, this reduction of water supply is affected by hedging schemes or hedging policies. This research work aims to compare the popular hedging policies: (i) linear two-point hedging; (ii) modified two-point hedging; and, (iii) discrete hedging based on time-varying and constant hedging parameters. A parameterization-simulation-optimization (PSO) framework is employed for the selection of the parameters of the compromising hedging policies. The multi-objective evolutionary search-based technique (Non-dominated Sorting based Genetic Algorithm-II) was used to identify the Pareto-optimal front of hedging policies that seek to obtain the trade-off between shortage ratio and vulnerability. The case example used for illustration is the Hemavathy reservoir in Karnataka, India. It is observed that the Pareto-optimal front that was obtained from time-varying hedging policies show significant improvement in reservoir performance when compared to constant hedging policies. The variation in the monthly parameters of the time-variant hedging policies shows a strong correlation with monthly inflows and available water.

Description: Water, Vol. 10, Pages 1308: Impact of Uncertainty of Floodplain Digital Terrain Model on 1D Hydrodynamic Flow Calculation Water doi: 10.3390/w10101308 Authors: Adam Kiczko Dorota Mirosław-Świątek This study investigates the effect of the Digital Terrain Model (DTM) uncertainty effect on the output of a 1D flow model. The analysis is performed for the lowland river Biebrza, covered with dense wetland vegetation, with a high uncertainty of terrain elevations. The DTM uncertainty is modeled in two ways: (1) accounting for the uncertainty spatial dependency on the basis of the correlogram function and (2) neglecting the correlation of the elevation points. The model explanation of water levels improves when elevation uncertainty is being included. Without the elevation uncertainty, the model provided a good fit only for peak flows, with uncertainty also representation of lower flows is better. It was shown that the correlation of the elevation uncertainty had a noticeable effect on the modeling outcomes, especially for near bankfull flows, where for the uncorrelated case water levels were underestimated by 5 cm, comparing to the correlated case. The effect was also present for inundation extents, obtained by an interpolation of computed water levels. The correlation of the elevation uncertainty strongly affects estimates of standard deviations of computed water levels, which were almost twice smaller when correlation was neglected. In the result, only when the correlation of the elevation uncertainty was included, it was possible to obtain confidence bands that enclosed observation points.

Description: Water, Vol. 10, Pages 1305: Effects of Crop Planting Structure Adjustment on Water Use Efficiency in the Irrigation Area of Hei River Basin Water doi: 10.3390/w10101305 Authors: Xin Han Zheng Wei Baozhong Zhang Congying Han Jianzheng Song The adjustment of crop planting structure can change the process of water and material circulation, and thus affect the total amount of water and evapotranspiration in the irrigation district. To guide the allocation of water resources in the region, it is beneficial to ascertain the effects of changing the crop planting structure on water saving and farmland water productivity in the irrigation district. This paper takes Yingke Irrigation District as the background. According to the continuous observation data from 2012 to 2013, Based on the modified Soil and Water Assessment Tool (SWAT) model and taking advantage of monthly scale remote sensing EvapoTranspiration (ET) and crop growth parameters (leaf area index and shoot dry matter), we tested the simulation accuracy of the model, proposed irrigation efficiency calculation methods considering water drainage, and established the scenario analysis method for the spatial distribution of crop planting structure. Finally, we evaluated the changes in water savings in irrigation district projects and resources, the irrigation water productivity and the net income water productivity under different planting structure scenarios. The results indicate that the efficiency of irrigation has increased by 15~20%, while considering drainage, as compared with conventional irrigation efficiency. Additionally, the adjustment of crop planting structure can reduce regional evapotranspiration by 14.9%, reduce the regional irrigation volume by 30%, and increase the net income of each regional water area by 16%.

Description: Water, Vol. 10, Pages 1307: Removal of Nutrients, Sediment, and Heavy Metals by a Stormwater Treatment Train; a Medium-Density Residential Case Study in Southeast Queensland Water doi: 10.3390/w10101307 Authors: Darren Drapper Andy Hornbuckle Urban stormwater runoff from a medium-density residential development in southeast Queensland has been monitored in the field since November 2013. A treatment train installed on the site includes rainwater tanks collecting roofwater, 200-micron mesh baskets installed in grated gully pits, and two 850-mm-high media filtration cartridges installed in an underground 4-m3 vault. The site has been monitored over a 4.5-year period. Removal efficiencies were observed at this site for the regulated pollutants; the corresponding values for total suspended solids (TSS), total phosphorus (TP), and total nitrogen (TN) for the pit baskets were 61%, 28%, and 45%, respectively. The cartridge filters removed 78% of TSS, 59% of TP, 42% of TN, 40% of total copper, and 51% of total zinc. As the measured influent TSS and TP concentrations to the cartridge filters were low when compared to industry guidelines, the U.S. field dataset was truncated to anticipated guideline levels, confirming results at 90% for TSS and 76% for TP. The total gross pollutant generation rate from the medium-density residential catchment was observed to be 0.24 m3/Ha/year, with a corresponding air-dried mass of 142.5 kg/Ha/year. Less than 2% of the gross pollutant mass was anthropogenic. This paper concludes that the treatment train, and in particular the media filter, provides good removal of total copper and total zinc as well as TSS, TP, and TN from urban stormwater runoff, with higher inlet concentrations producing better performance. Field test data from 58 months of operation and standard maintenance suggests that breakthrough of TSS and TP has not occurred yet.

Description: Water, Vol. 10, Pages 1306: Quantitative Analysis of Membrane Fouling Mechanisms Involved in Microfiltration of Humic Acid–Protein Mixtures at Different Solution Conditions Water doi: 10.3390/w10101306 Authors: Chunyi Sun Na Zhang Fazhan Li Guoyi Ke Lianfa Song Xiaoqian Liu Shuang Liang A systematical quantitative understanding of different mechanisms, though of fundamental importance for better fouling control, is still unavailable for the microfiltration (MF) of humic acid (HA) and protein mixtures. Based on extended Derjaguin–Landau–Verwey–Overbeek (xDLVO) theory, the major fouling mechanisms, i.e., Lifshitz–van der Waals (LW), electrostatic (EL), and acid–base (AB) interactions, were for the first time quantitatively analyzed for model HA–bovine serum albumin (BSA) mixtures at different solution conditions. Results indicated that the pH, ionic strength, and calcium ion concentration of the solution significantly affected the physicochemical properties and the interaction energy between the polyethersulfone (PES) membrane and HA–BSA mixtures. The free energy of cohesion of the HA–BSA mixtures was minimum at pH = 3.0, ionic strength = 100 mM, and c(Ca2+) = 1.0 mM. The AB interaction energy was a key contributor to the total interaction energy when the separation distance between the membrane surface and HA–BSA mixtures was less than 3 nm, while the influence of EL interaction energy was of less importance to the total interaction energy. The attractive interaction energies of membrane–foulant and foulant–foulant increased at low pH, high ionic strength, and calcium ion concentration, thus aggravating membrane fouling, which was supported by the fouling experimental results. The obtained findings would provide valuable insights for the quantitative understanding of membrane fouling mechanisms of mixed organics during MF.

Description: Water, Vol. 10, Pages 1315: Developing an EFDC and Numerical Source-Apportionment Model for Nitrogen and Phosphorus Contribution Analysis in a Lake Basin Water doi: 10.3390/w10101315 Authors: Hui Bai Yan Chen Dong Wang Rui Zou Huanzhen Zhang Rui Ye Wenjing Ma Yunhai Sun The numerical source-apportionment model is an efficient and useful method for analyzing water-quality responses to nutrient loading in rivers and lakes. In this study, the Environmental Fluid Dynamic Code (EFDC) and numerical source-apportionment model were applied to Lake Bali in Jiujiang City, China to predict the contributions of various pollution sources to the lake at any time and position. We calibrated and validated the model by comparing its predictions with observed hydrodynamic and water-quality parameters from 2014 to 2015. Application of the calibrated model to simulate water-quality responses to a pollution source showed that the contribution of a pollution source to water quality in the lake has strong spatial heterogeneity. The results provide useful information for the optimization of pollution load reduction in Lake Bali and can be used to determine the most effective implementation of its pollution-control plan. The model built in this study can also be used for pollution source-apportionment in other urban lakes and is superior to other traditional source-apportionment models.

Description: Water, Vol. 10, Pages 1316: Greener Method for the Removal of Toxic Metal Ions from the Wastewater by Application of Agricultural Waste as an Adsorbent Water doi: 10.3390/w10101316 Authors: Rabia Baby Shaikh Bullo Saifullah Fawad ur Rehman Ruqia Iqbal Shaikh The presence of inorganic pollutants such as metal ions (Ni2+, Pb2+, Cr6+) in water, probably by long-term geochemical changes and from the effluents of various industries, causes diseases and disorders (e.g., cancer, neurodegenerative diseases, muscular dystrophy, hepatitis, and multiple sclerosis). Conventional methods for their removal are limited by technical and economic barriers. In biosorption, low-cost and efficient biomaterials are used for this purpose. In this study, Brassica Campestris stems from the agriculture waste and has been used for the removal of Ni2+, Cr6+ and Pb2+ ions from an aqueous solution containing all the ions. Effect of different parameters, e.g., pH, contact time, metal ion initial concentration, adsorbent dose, agitation rate and temperature were analyzed and optimized. The adsorbent worked well for removal of the Pb2+ and Cr6+ as compared to Ni2+. The atomic absorption spectrophotometer (AAS) and FTIR investigation of adsorbent before and after shows a clear difference in the adsorbent capability. The highest adsorption percentage was found at 98%, 91%, and 49% respectively, under the optimized parameters. Furthermore, the Langmuir isotherm was found better in fitting to the experimental data than that of the Freundlich isotherm.

Description: Water, Vol. 10, Pages 1052: Assessing the Hydrologic Performance of a Green Roof Retrofitting Scenario for a Small Urban Catchment Water doi: 10.3390/w10081052 Authors: Anna Palla Ilaria Gnecco Paolo La Barbera In an existing urban environment, retrofitting low impact development (LID) solutions can provide an opportunity to address flooding and water quality problems. Taking into account the need to effectively estimate the impact of vegetated LIDs, particular attention has recently been given on the evapotranspiration (ET) process that is responsible for the restoring of green roof water-holding capacity. The present study aims to develop a methodological approach to estimate the actual ET as climate input data in the United States Environmental Protection Agency (EPA) Storm Water Management Model (SWMM) continuous simulation. The proposed approach is calibrated on a single green roof installation based on one-minute continuous simulations over 26 years of climate records. Then the calibrated methodological approach has been implemented to perform continuous simulation of a small urban catchment retrofitted with green roofs. Based on simulation results, the peak and volume reduction rate evaluated for the 1433 rainfall events are equal to 0.3 on average (with maximum values of 0.96 for peak and 0.86 for volume). In general, the adopted methodology indicates that the actual ET estimate is needed to suitably assess the hydrologic performance of vegetated LIDs mainly concerning the volume reduction index; furthermore, the methodology can be easily replicated for other vegetated LID applications.

Description: Water, Vol. 10, Pages 1053: Reducing High Flows and Sediment Loading through Increased Water Storage in an Agricultural Watershed of the Upper Midwest, USA Water doi: 10.3390/w10081053 Authors: Nate Mitchell Karthik Kumarasamy Se Jong Cho Patrick Belmont Brent Dalzell Karen Gran Climate change, land clearing, and artificial drainage have increased the Minnesota River Basin’s (MRB) stream flows, enhancing erosion of channel banks and bluffs. Accelerated erosion has increased sediment loads and sedimentation rates downstream. High flows could be reduced through increased water storage (e.g., wetlands or detention basins), but quantifying the effectiveness of such a strategy remains a challenge. We used the Soil and Water Assessment Tool (SWAT) to simulate changes in river discharge from various water retention site (WRS) implementation scenarios in the Le Sueur watershed, a tributary basin to the MRB. We also show how high flow attenuation can address turbidity issues by quantifying the impact on near-channel sediment loading in the watershed’s incised reaches. WRS placement in the watershed, hydraulic conductivity (K), and design depth were varied across 135 simulations. The dominant control on site performance is K, with greater flow reductions allowed by higher seepage rates and less frequent overflowing. Deeper design depths enhance flow reductions from sites with low K values. Differences between WRS placement scenarios are slight, suggesting that site placement is not a first-order control on overall performance in this watershed. Flow reductions exhibit power-law scaling with exceedance probability, enabling us to create generalized relationships between WRS extent and flow reductions that accurately reproduce our SWAT results and allow for more rapid evaluation of future scenarios. Overall, we show that increasing water storage within the Le Sueur watershed can be an effective management option for high flow and sediment load reduction.

Description: Water, Vol. 10, Pages 1051: In Situ Water Quality Improvement Mechanism (Nitrogen Removal) by Water-Lifting Aerators in a Drinking Water Reservoir Water doi: 10.3390/w10081051 Authors: Zizhen Zhou Tinglin Huang Weijin Gong Yang Li Yue Liu Fuwang Zhao Yanyan Dou Shilei Zhou Weixing Ma A field scale experiment was performed to explore the nitrogen removal performance of the water and surface sediment in a deep canyon-shaped drinking water reservoir by operating WLAs (water-lifting aerators). Nitrogen removal performance was achieved by increasing the densities and N-removal genes (nirK and nirS) of indigenous aerobic denitrifiers. After the operation of WLAs, the total nitrogen removal rate reached 29.1 ± 0.8% in the enhanced area. Ammonia and nitrate concentrations were reduced by 72.5 ± 2.5% and 40.5 ± 2.1%, respectively. No nitrite accumulation was observed. Biolog results showed improvement of carbon metabolism and carbon source utilization of microbes in the enhanced area. Miseq high-throughput sequencing indicated that the denitrifying bacteria percentage was also higher in the enhanced area than that in the control area. Microbial communities had changed between the enhanced and control areas. Thus, nitrogen removal through enhanced indigenous aerobic denitrifiers by the operation of WLAs was feasible and successful at the field scale.

Description: Water, Vol. 10, Pages 1050: Seasonal Variation of Drainage System in the Lower Ablation Area of a Monsoonal Temperate Debris-Covered Glacier in Mt. Gongga, South-Eastern Tibet Water doi: 10.3390/w10081050 Authors: Qiao Liu Shiyin Liu Wulong Cao Seasonal evolution of the subglacial drainage system in the lower ablation area of the Hailuogou glacier ice tongue were revealed by repeated dye tracer (Rhodamine WT) experiments during the 2009 ablation season. Between April and October, 18 dye tracer experiments were conducted by injecting the tracer at one location of the lower ablation area of the Hailuogou Glacier to diagnose the seasonal variation of the subglacial drainage system of this section of glacier ice tongue. Using a simple advection-dispersion model (ADM), the flow velocity, hydrodynamic dispersion coefficient, and degree of tracer spreading were deduced. Tracer transit velocity through the tested subglacial channel varied from 0.148 to 0.555 m s−1 during the 2009 ablation season. Dispersivity showed a relatively high value than that found at other glaciers, which varied between 27.05 and 287.49 m2 s−1. Seasonal changes of these indexes indicated that the subglacial drainage system of the lower ablation area of the Hailougou Glacier is a relatively stable existing system in the case of its longitudinal shape, whereas its hydraulic efficiency is low in the early and late ablation seasons and high during the middle of summer due to subglacial channel expansion.

Description: Water, Vol. 10, Pages 1057: Combined Effects of Experimental Warming and Eutrophication on Phytoplankton Dynamics and Nitrogen Uptake Water doi: 10.3390/w10081057 Authors: Chen Yu Chao Li Tao Wang Min Zhang Jun Xu Shallow lakes are highly vulnerable to damages caused by human activities and warming trends. To assess whether and how community structures of phytoplankton and nitrogen uptake respond to the combined effects of elevated temperature and eutrophication, we performed a mesocosm experiment in field by combining a 4.5 °C increase in temperature and the addition of phosphorus. Our results demonstrated that the combination of rising temperatures and phosphorus loading stimulated the maximum biomass built up by the phytoplankton community, and changed the phytoplankton community by significantly increasing the number of Chlorophyta and Cyanophyta, and decreasing that of Cryptophyta. We also examined the effects of climate warming and eutrophication on phytoplankton nitrogen uptake and dynamics using 15N tracer techniques. The addition of phosphorus slightly increased the phytoplankton nitrate uptake velocity and relative preference index, but decreased the nitrate uptake turnover time. Warming relatively increased the ammonium uptake velocity and the relative preference index, but decreased the ammonium turnover time. In kinetic studies, NH4+ exhibited a higher maximum uptake rate (Vmax) and a lower half-saturation constant (Ks) than NO3− substrates due to temperature elevation and the addition of phosphorus. Hence, warming and eutrophication increased the capacity of phytoplankton for NH4+ uptake and their affinity at low substrate concentrations. Thus, the combined effects of climate warming and phosphorus nutrient availability may increase the prevalence of Chlorophyta and Cyanophyta, and change the nitrogen cycling of aquatic ecosystems.

Description: Water, Vol. 10, Pages 1058: Soil and Water Conservation in Rainfed Vineyards with Common Sainfoin and Spontaneous Vegetation under Different Ground Conditions Water doi: 10.3390/w10081058 Authors: Nahed Ben-Salem Sara Álvarez Manuel López-Vicente Soil erosion seriously affects vineyards. In this study, the influence of two vegetation covers on topsoil moisture and the effect of different physiographic conditions on runoff and sediment yields were evaluated in a rainfed vineyard formed by four fields (NE Spain) during 15 months. One field had spontaneous vegetation in the inter-row areas, and three fields had a cover crop of common sainfoin. Moisture conditions were dry and stable in the vineyards’ rows, wet and very variable in the inter-row areas and wet and very stable in the corridors. Topsoil moisture in the areas with common sainfoin was much higher than in the rows (62–70%), whereas this difference was lower with spontaneous vegetation (40%). Two runoff and sediment traps (STs) were installed in two ephemeral gullies, and 26 time-integrated surveys (TIS) were done. The mean runoff yields were 9.8 and 13.5 L TIS−1 in ST2 and ST3. Rainfall depth (12 mm) and erosivity (5.2 MJ mm ha−1 h−1) thresholds for runoff initiation were assessed. The mean turbidity was 333 (ST2) and 19 (ST3) g L−1. Changes in the canopy covers (grapevines and vegetation covers), topography and rainfall parameters explained the runoff and sediment dynamics.

Description: Water, Vol. 10, Pages 1070: Quantification Assessment of Extraneous Water Infiltration and Inflow by Analysis of the Thermal Behavior of the Sewer Network Water doi: 10.3390/w10081070 Authors: Maryam Beheshti Sveinung Sægrov Infiltration and inflow (I/I) of unwanted water in separate urban sewer networks are critical issues for sustainable urban water management. Accurate quantification of unwanted water I/I from individual sources into a sewer system is an essential task for assessing the status of the sewer network and conducting rehabilitation measures. The study aim was to quantify extraneous water I/I into a sanitary sewer network by a temperature-based method, i.e., fiber-optic distributed temperature sensing (DTS), which was applied for the first time in a separate sewer network of a catchment in Trondheim, Norway. The DTS technology is a relatively new technology for sewer monitoring, developed over the past decade. It is based on continual temperature measurement along a fiber-optic cable installed in the sewer network. The feasibility of this method has been tested in both experimental discharges and for the rainfall-derived I/I. The results achieved from the monitoring campaign established the promising applicability of the DTS technique in the quantification analysis. Furthermore, the application of this method in quantifying real-life, rainfall-derived I/I into the sewer system was demonstrated and verified during wet weather conditions.

Description: Water, Vol. 10, Pages 1066: Adaptation of an Existing Intake Structure Caused by Increased Sediment Level Water doi: 10.3390/w10081066 Authors: Roman Gabl Bernhard Gems Florian Birkner Bernhard Hofer Markus Aufleger An unexpected and massive redistribution of fine sediment in a large Alpine reservoir was triggered by a further lowering of the water level to conduct maintenance work. This caused the need of a total redesign of the existing head race intake for a high head power plant in the Austrian Alps. Two main geometry options for the trash rack support structure are compared with numerical simulations (ANSYS-CFX) as well as with a scale model test (scale 1:20). The laboratory experiment substantially benefited from the preliminary numerical investigation in respect of the location and implementation of the model boundaries. In return was the confidence in the numerics strengthened by the successful validation of the local head loss and the velocity distribution for the main operation cases. This allowed that the main inputs for the structural design and the further optimisation is conducted only with the 3D-numerical tool. The paper presents the interlaced concept as well as the main finding of the investigation, which lead to a successful adaptation of the intake structure.

Description: Water, Vol. 10, Pages 1064: The Application of a Modified Version of the SWAT Model at the Daily Temporal Scale and the Hydrological Response unit Spatial Scale: A Case Study Covering an Irrigation District in the Hei River Basin Water doi: 10.3390/w10081064 Authors: Zheng Wei Baozhong Zhang Yu Liu Di Xu As a well-built, distributed hydrological model, the Soil and Water Assessment Tool (SWAT) has rarely been evaluated at small spatial and short temporal scales. This study evaluated crop growth (specifically, the leaf area index and shoot dry matter) and daily evapotranspiration at the hydrological response unit (HRU) scale, and SWAT2009 was modified to accurately simulate crop growth processes and major hydrological processes. The parameters of the modified SWAT2009 model were calibrated using data on maize for seed from 5 HRUs and validated using data from 7 HRUs. The results show that daily evapotranspiration, shoot dry matter and leaf area index estimates from the modified SWAT2009 model were satisfactory at the HRU level, and the RMSE values associated with daily evapotranspiration, shoot dry matter, and leaf area index were reduced by 17.0%, 1.6%, and 71.2%, compared with SWAT2009. Thus, the influences of various optimal management practices on the hydrology of agricultural watersheds can be effectively assessed using the modified model.

Description: Water, Vol. 10, Pages 1067: High-Resolution Electrical Resistivity Tomography (ERT) to Characterize the Spatial Extension of Freshwater Lenses in a Salinized Coastal Aquifer Water doi: 10.3390/w10081067 Authors: Nicolas Greggio Beatrice M. S. Giambastiani Enrico Balugani Chiara Amaini Marco Antonellini High-resolution electrical resistivity tomography (ERT) with electrode spacing of 1 m proved to be an effective methodology to characterize ephemeral, sparse, and discontinuous freshwater lenses within the almost completely salinized shallow aquifer of the low coastal zone near Ravenna. ERT profiles with a vertical resolution of 0.25–0.5 m, once calibrated with groundwater data (water table depth and electrical conductivity) collected in multi-level sampler systems at the same spatial resolution, are reliable and provide repeatable measurements in time. The ERT methodology allows for fast data acquisition over large areas and it also permits the study of the evolution in time of freshwater availability in coastal zones, which is important for local ecosystems and soil resources. This makes high-resolution ERT a valid tool to aid local stakeholders and decision makers to effectively manage freshwater lenses, and guarantee their preservation or augmentation by means of managed aquifer recharge.

Description: Water, Vol. 10, Pages 1061: Change and Climatic Linkage for Extreme Flows in Typical Catchments of Middle Tianshan Mountain, Northwest China Water doi: 10.3390/w10081061 Authors: Yonggang Ma Yue Huang Tie Liu Due to an absence of an essential daily data set, changing characteristics, and cause of flow extremes in the Tianshan Mountains are rarely explored in depth. In this study, daily based long-term meteorological and hydrological observation data were collected in four typical watersheds in the middle Tianshan Mountains; Manne-Kendall trend analysis and Pettit’s test were used to detect the trends and alterations of extreme flow series; Generalized Extreme Value distribution (GEV) and General Pareto distribution (GDP) models were used to describe the probability distributions of annual maximum (AM) and peaks over threshold (POT) series based on daily discharge; and the relationship between extreme flow and climate indices, were also investigated. The findings indicated that, change of the AM series at five hydrological stations experienced positive trends; the POT series generally showed no significant trends, while the peaks over threshold number (POTN) present a positive trend at the five stations. Change points exist in the POT and occurrence time of maximum daily discharge in spring (AM-SPR) series at the Kensiwate (KSWT) station in Manas watershed; the mean extreme flow decreased after 1986, and the occurrence time the annual maximum daily flow in spring significant forward after 1978. The AM series can well fit the GEV distribution, while the POT series fit the GDP distribution better; the GEV model performed worse in estimating flood events with high return period than low return period events. Moreover, acceleration of glacier melting lead to the magnitude and frequency increments of flood in the north slope; intensifying and frequent precipitation extremes are dominate factors of extreme flow variations in south slope watersheds which without large amount of glacier coverage; and continually temperature rising in spring and increased precipitation in winter lead to the change on magnitude and timing of spring extreme floods.

Description: Water, Vol. 10, Pages 1060: Assessment of Heavy Metal Pollution in the Sediment of the Main Tributaries of Dongting Lake, China Water doi: 10.3390/w10081060 Authors: Jinying Xu Yuwei Chen Lilin Zheng Baogui Liu Jinfu Liu Xiaolong Wang Heavy metal pollution in sediment is one of the most serious problems in water bodies, including rivers, which can cause secondary pollution when environmental conditions change. In this study, surface sediment samples collected from the four main tributaries of Dongting Lake (i.e., Xiangjiang River (XR), Zishui River (ZR), Yuanjiang River (YR), and Lishui River (LR)) were analyzed for concentrations of Zn, Cr, Cu, As, Cd, and Pb. The spatial distribution, source, and potential ecological risk of these metals were determined. The results suggest a great spatial heterogeneity of heavy metals in the sediment of the studied rivers. Heavy metals had highest concentrations in the sediment of XR, especially midstream and downstream. A principal component analysis (PCA) and correlation analysis indicated that Cd and As were mainly from industrial wastewater and mineral mining, Cr came from natural process and agricultural activities, and Zn and Cu potentially from both. Pb was originated from atmospheric deposition and river inflow transportation. According to the geo-accumulation index ( I g e o ), enrichment factor (EF), and risk index (RI) assessment, heavy metals pollution was highest in the sediment of XR, and Cd was the main pollutant in the sediment of XR, presenting considerable potential ecological risk. This may contribute to heavy metal pollution in Dongting Lake. This paper provides a reference for the aquatic environmental management of heavy metals in Dongting Lake area and its tributaries.

Description: Water, Vol. 10, Pages 1068: Modeling Approach for Water-Quality Management to Control Pollution Concentration: A Case Study of Ravi River, Punjab, Pakistan Water doi: 10.3390/w10081068 Authors: Muhammad Mazhar Iqbal Muhammad Shoaib Paul Agwanda Jung Lyul Lee One of the challenging problems of Punjab, the most populous province of Pakistan, is the surface water-quality problem of the Ravi River, which flows through the main cities of the province. At present, the overall status of water quality is very polluted, primarily due to residential and industrial wastewater directly discharged into the Ravi River through a network of drains. Due to the poor quality of the water, the river ecosystem is not favorable for the aquatic and surrounding environment. Hence, management options are proposed to reduce pollution. Therefore, the study was formulated to identify the main sources of pollution along the Ravi River and their potential impact on the course of the river channel. In addition, the study applied a numerical model WASP 8.1 (Water Quality Simulation Program) to discover the best strategy for the improvement of water quality. Through the model simulation it was found that, if the flow at headwater and link canals is increased up to 50%, along with 75% improvement in the pollution concentration of drains through wastewater-treatment facilities, the water quality of the Ravi River can be improved up to an acceptable limit of water-quality standards.

Description: Water, Vol. 10, Pages 1069: Effect of TSS Removal from Stormwater by Mixed Media Column on T-N, T-P, and Organic Material Removal Water doi: 10.3390/w10081069 Authors: Hoi Jin Kim Jae-Woo Choi Tae-Han Kim Jong-Sup Park Byungryul An The water quality of a waterbody influenced by stormwater runoff was tested in a lab-scale setting by filtration. The filtration bed was packed with two or three types of media, sand, bottom ash (BA), and woodchips (WC), and tested with three hydraulic conductivities (HCs). Five pollutants—namely, total suspended solids (TSS): BOD, COD, T-N, and T-P, were analyzed and compared. The application of sand-bottom ash (S-BA) and bottom ash-sand (BA-S) media types showed the highest removal efficiencies for TSS, BOD, COD, T-N, and T-P, respectively. Among the five pollutants, TSS achieved the highest removal efficiency for any of the filter media, which was up to 93% for the S-BA and decreased to 72% with an increase in HC, followed by T-P > BOD > COD = T-N. The maximum removal efficiency values of BOD and COD were obtained at 67% and 52%, respectively, indicating that BOD removal was always higher than COD removal. Due to the low C:N and high HC, biodegradation was disregarded during filtration. Based on the different removal forms of T-P compared with TSS, adsorption would be involved in the removal of dissolved T-P by BA.

Description: Water, Vol. 10, Pages 1063: An Effective Kalman Filter-Based Method for Groundwater Pollution Source Identification and Plume Morphology Characterization Water doi: 10.3390/w10081063 Authors: Simin Jiang Jinhong Fan Xuemin Xia Xianwen Li Ruicheng Zhang The identification of unknown groundwater pollution sources and the characterization of pollution plume remains a challenging problem. In this study, we addressed this problem by a linked simulation-optimization approach. This approach couples a contaminant transport simulation model with a Kalman filter-based method to identify groundwater pollution source and characterize plume morphology. In the proposed methodology, the concentration field library, the covariance reduction with a Kalman filter, an alpha-cut technique of fuzzy set, and a linear programming model are integrated for solving this inverse problem. The performance of this methodology is evaluated on an illustrative groundwater pollution source identification problem. The evaluation considered the random hydraulic conductivity filed, erroneous monitoring data, a prior information shortage of potential pollution sources, and an unexpected and unknown pumping well. The identified results indicate that, under these conditions, the proposed Kalman filter-based optimization model can give satisfactory estimations to pollution sources and plume morphology for domains with small and moderate heterogeneity but cannot validate the transport in the relatively high heterogeneous field.

Description: Water, Vol. 10, Pages 1083: Determination of Micropollutants in Water Samples from Swimming Pool Systems Water doi: 10.3390/w10081083 Authors: Anna Lempart Edyta Kudlek Mariusz Dudziak The present study investigated the occurrence of selected micropollutants, including emerging contaminants from a group of pharmaceuticals and personal care products (PPCPs) in water samples from swimming pool systems. The study area was selected based on the lack of available information regarding suspected contamination of swimming pool water by PPCPs. The variety and concentration of chemical compounds in these aquatic systems can be quite diversified, presenting a challenge in terms of both purification and quality control. Determination of PPCPs requires very sensitive analytical methods that make it possible to confirm the presence of tested compounds in a complex organic extract. In this field, gas chromatography-mass spectrometry (GC-MS) can be used. With this system, selected ion monitoring can be performed, which reduces the detection limits of the investigated analyte. This paper aims to present an analytical method and strategy that can be adapted to obtain information on the composition of water in swimming pool systems. The sample preparation methodology, including Solid Phase Extraction, has been developed for the trace determination of two pharmaceuticals—caffeine, carbamazepine—and one sunscreen constituent—benzophenone-3—in swimming pool water samples.

Description: Water, Vol. 10, Pages 1082: Low Water Productivity for Rice in Bihar, India—A Critical Analysis Water doi: 10.3390/w10081082 Authors: Omaid Najmuddin Golam Rasul Abid Hussain David Molden Shahriar Wahid Bijan Debnath Rice is the most important crop for food security and livelihoods of the rural population in Bihar, India. In spite of good soil and water resources, rice water productivity (WP) is very low in Bihar. Trends in WP and key factors influencing WP over 20 years (1991–2010) in 11 Bihar districts were analysed using panel data to help elucidate reasons for low WP values. The annual average rice yield of 938 kg/ha, WP of 0.22 kg/m3, and marginal physical productivity (MPP) of 249 g/m3 are very low in Bihar compared to both the national average for India and other rice growing areas in the world. Rice WP and MPP were higher for the garma (dry) season than for the kharif (monsoon) season. Temporal analysis showed that WP was slowly declining in most districts, while spatial analysis showed a significant variation in WP across the districts. Regression analysis showed that the availability of irrigation facilities, occurrence of flood and drought, and cropping intensity had significant influence on rice WP. Causes for temporal and spatial changes in WP are highlighted and actions to improve rice WP in Bihar are suggested.

Description: Water, Vol. 10, Pages 1081: Water Stewardship: Attributes of Collaborative Partnerships between Mining Companies and Communities Water doi: 10.3390/w10081081 Authors: Jocelyn Fraser Nadja C. Kunz With many of the world’s largest mines operating in jurisdictions of water scarcity, competition for water has become a frequent source of tension between mining companies and other water users. Water stewardship is, therefore, becoming an important strategy for the mining sector to address stakeholder concerns and earn social acceptance. Collaborative partnerships between mining and other water users are a necessary component of advancing water stewardship, but the attributes needed to implement a successful water stewardship strategy are understudied. This paper addresses this gap by examining two exploratory case studies in Peru and Mongolia, where collaboration has been used as a strategy for promoting more sustainable outcomes in water-scarce regions. The findings suggest that while questions remain about who is best suited to lead collaborative partnerships, trust in the entity responsible for leading collaborative partnerships (especially in situations of high conflict) and a willingness to allow each partner to play to their strengths are critical attributes of success. We conclude that the outcome of collective action between mining companies and other water users offers the potential to deliver both business and social value, and to advance more sustainable water management.

Description: Water, Vol. 10, Pages 1080: Nitrogen and Phosphorus Uptake Dynamics in Tropical Cerrado Woodland Streams Water doi: 10.3390/w10081080 Authors: Nícolas Reinaldo Finkler Flavia Tromboni Iola Gonçalves Boëchat Björn Gücker Davi Gasparini Fernandes Cunha Pollution abatement through phosphorus and nitrogen retention is a key ecosystem service provided by streams. Human activities have been changing in-stream nutrient concentrations, thereby altering lotic ecosystem functioning, especially in developing countries. We estimated nutrient uptake metrics (ambient uptake length, areal uptake rate, and uptake velocity) for nitrate (NO3–N), ammonium (NH4–N), and soluble reactive phosphorus (SRP) in four tropical Cerrado headwater streams during 2017, through whole-stream nutrient addition experiments. According to multiple regression models, ambient SRP concentration was an important explanatory variable of nutrient uptake. Further, best models included ambient NO3–N and water velocity (for NO3–N uptake metrics), dissolved oxygen (DO) and canopy cover (for NH4–N); and DO, discharge, water velocity, and temperature (for SRP). The best kinetic models describing nutrient uptake were efficiency-loss (R2 from 0.47–0.88) and first-order models (R2 from 0.60–0.85). NO3–N, NH4–N, and SRP uptake in these streams seemed coupled as a result of complex interactions of biotic P limitation, abiotic P cycling processes, and the preferential uptake of NH4–N among N-forms. Global change effects on these tropical streams, such as temperature increase and nutrient enrichment due to urban and agricultural expansion, may have adverse and partially unpredictable impacts on whole-stream nutrient processing.

Description: Water, Vol. 10, Pages 1088: Estimating Evapotranspiration of Processing Tomato under Plastic Mulch Using the SIMDualKc Model Water doi: 10.3390/w10081088 Authors: Huimeng Zhang Guanhua Huang Xu Xu Yunwu Xiong Quanzhong Huang Accurate estimation of crop evapotranspiration (ET) is critical for agricultural water resource management and proper irrigation scheduling. The 2-year field experimental data of processing tomato under plastic-mulched drip and basin irrigation in the Hetao Irrigation District (Hetao), located in the upper reaches of the Yellow river, were used to calibrate and validate the SIMDualKc model. The model adopted the Food and Agriculture Organization (FAO) dual Kc method for partitioning ET into plant transpiration and soil evaporation. The results showed a good agreement between soil water observations and simulations throughout the growing seasons with a low error estimate and high model efficiency. The calibrated basal potential crop coefficients for the initial stage, mid-season stage, and late stage were 0.30, 0.92, and 0.60, respectively. ET during the two growing seasons was in the range of 284–331 mm for basin irrigation and 266–310 mm for drip irrigation. The average soil evaporation accounted for 5% of ET in 2015 and 14% of ET in 2016 for drip irrigation treatments, while it accounted for 4% and 13% of ET for basin irrigation treatments in the two experimental years, indicating that transpiration was the dominant component of ET of processing tomato under plastic mulch in Hetao. The highest water productivity was obtained from the drip irrigation treatment. The SIMDualKc model is an appropriate tool to estimate crop ET and may be further used to improve local irrigation scheduling for processing tomato in the upper reaches of the Yellow river.

Description: Water, Vol. 10, Pages 1089: Spatiotemporal Variability in Extreme Precipitation in China from Observations and Projections Water doi: 10.3390/w10081089 Authors: Yifeng Peng Xiang Zhao Donghai Wu Bijian Tang Peipei Xu Xiaozheng Du Haoyu Wang Extreme precipitation events, which have intensified with global warming over the past several decades, will become more intense in the future according to model projections. Although many studies have been performed, the occurrence patterns for extreme precipitation events in past and future periods in China remain unresolved. Additionally, few studies have explained how extreme precipitation events developed over the past 58 years and how they will evolve in the next 90 years as global warming becomes much more serious. In this paper, we evaluated the spatiotemporal characteristics of extreme precipitation events using indices for the frequency, quantity, intensity, and proportion of extreme precipitation, which were proposed by the World Meteorological Organization. We simultaneously analyzed the spatiotemporal characteristics of extreme precipitation in China from 2011 to 2100 using data obtained from the Coupled Model Intercomparison Project Phase 5 (CMIP5) models. Despite the fixed threshold, 95th percentile precipitation values were also used as the extreme precipitation threshold to reduce the influence of various rainfall events caused by different geographic locations; then, eight extreme precipitation indices (EPIs) were calculated to evaluate extreme precipitation in China. We found that the spatial characteristics of the eight EPIs exhibited downward trends from south to north. In the periods 1960–2017 and 2011–2100, trends in the EPIs were positive, but there were differences between different regions. In the past 58 years, the extreme precipitation increased in the northwest, southeast, and the Tibet Plateau of China, while decreased in northern China. Almost all the trends of EPIs are positive in the next two periods (2011–2055 and 2056–2100) except for some EPIs, such as intensity of extreme precipitation, which decrease in southeastern China in the second period (2056–2100). This study suggests that the frequency of extreme precipitation events in China will progressively increase, which implies that a substantial burden will be placed on social economies and terrestrial ecological processes.

Description: Water, Vol. 10, Pages 1087: Integration of DSM and SPH to Model Tailings Dam Failure Run-Out Slurry Routing Across 3D Real Terrain Water doi: 10.3390/w10081087 Authors: Kun Wang Peng Yang Karen A. Hudson-Edwards Wensheng Lyu Chao Yang Xiaofei Jing Tailings dam failure accidents occur frequently, causing substantial damage and loss of human and animal life. The prediction of run-out tailings slurry routing following dam failures is of great significance for disaster prevention and mitigation. Using satellite remote sensing digital surface model (DSM) data, tailings pond parameters and the advanced meshless smoothed particle hydrodynamics (SPH) method, a 3D real-scale numerical modelling method was adopted to study the run-out tailings slurry routing across real downstream terrains that have and have not been affected by dam failures. Three case studies, including a physical modelling experiment, the 2015 Brazil Fundão tailings dam failure accident and an operating high-risk tailings pond in China, were carried out. The physical modelling experiment and the known consequences were successfully modeled and validated using the SPH method. This and the other experiments showed that the run-out tailings slurry would be tremendously destructive in the early stages of dam failure, and emergency response time would be extremely short if the dam collapses at its full designed capacity. The results could provide evidence for disaster prevention and mitigation engineering, emergency management plan optimization, and the development of more responsible site plans and sustainable site designs. However, improvements such as rheological model selection, terrain data quality, computing efficiency and land surface roughness need to be made for future studies. SPH numerical modelling is a powerful and advanced technique that is recommended for hazard assessment and the sustainable design of tailings dam facilities globally.

Description: Water, Vol. 10, Pages 1101: Analysis of Irrigation Canal System Characteristics in Heilongjiang Province and the Influence on Irrigation Water Use Efficiency Water doi: 10.3390/w10081101 Authors: Tianxiao Li Mengxin Sun Qiang Fu Song Cui Dong Liu Irrigation water use efficiency is a primary evaluation index that links economic production development with the efficient use of water resources. Canal water conveyance is an important part of irrigation, and the distribution characteristics of canal systems have an important influence on irrigation water use efficiency. In this paper, 75 irrigated districts in Heilongjiang Province in 2015 were selected as the study objects. The main, branch, lateral, and sublateral canals were graded into first-, second-, third-, and fourth-order classes, respectively. The irrigation districts were divided into three classes, that is, four-order, three-order, and two-order, according to the canal orders that the irrigation districts contained. The canal system framework was described by Horton’s law. The fractal dimension of the canal system was calculated based on the bifurcation ratio and length ratio of the canals. The relationships between fractal dimensions and irrigation water use efficiency were evaluated. The results showed that the irrigation water use efficiency of the four-order and three-order irrigation districts initially increased and then decreased with increases in the fractal dimension (D). In the irrigation districts, an irrigation water use efficiency of more than 10 × 103 hm2 and less than 0.67 × 103 hm2 was proportional to the increase in the fractal dimension, whereas the opposite result was found for districts with (0.67–10) × 103 hm2. The irrigation water use efficiency of the four-order and two-order irrigation districts with less than 3.3 × 103 hm2 had the greatest potential to increase the water use efficiency. Therefore, canal system reconstruction suggestions for different irrigation districts were provided. The results have important theoretical significance and practical value for the improvement of irrigation construction and the promotion of irrigation water efficiency planning.

Description: Water, Vol. 10, Pages 1103: Spatial Variations in the Abundance and Chemical Speciation of Phosphorus across the River–Sea Interface in the Northern Beibu Gulf Water doi: 10.3390/w10081103 Authors: Bin Yang Zhen-Jun Kang Dong-Liang Lu Solomon Felix Dan Zhi-Ming Ning Wen-Lu Lan Qiu-Ping Zhong Water samples were collected to measure dissolved and particulate phosphorus species in order to examine the dynamics of phosphorus in the water column across the river–sea interface from the lower Dafengjiang River to the open Beibu Gulf. Dissolved inorganic phosphorus concentrations were as high as 0.90 ± 0.42 μM in river water but decreased dramatically to as low as 0.02 ± 0.01 μM in open coastal waters. Total dissolved phosphorus was largely measured in the form of dissolved inorganic phosphorus in river waters (58% ± 18%), whereas dissolved organic phosphorus became the predominant species (>90% on average) in open coastal waters. Total dissolved phosphorus was the dominant species, comprising 76% ± 16% of the total phosphorus, while total particulate phosphorus only comprised 24% ± 16% of the total phosphorus pool. Riverine inputs, physical and biological processes, and particulate phosphorus regeneration were the dominant factors responsible for the dynamic variations of phosphorus species in the study area. Based on a two-end-member mixing model, the biological uptake resulted in a dissolved inorganic phosphorus depletion of 0.12 ± 0.08 μM in the coastal surface water, whereas the replenishment of dissolved inorganic phosphorus in the lower river from particle P regeneration and release resulted in an increase (0.19 ± 0.22 μM) of dissolved inorganic phosphorus in the estuarine mixing region. The molar ratios of dissolved inorganic nitrogen to dissolved inorganic phosphorus and dissolved silicate to dissolved inorganic phosphorus in the open surface waters were >22, suggesting that, although the lower Dafengjiang River contained elevated concentrations of dissolved inorganic phosphorus, the northern Beibu Gulf was an overall P-limited coastal ecosystem.

Description: Water, Vol. 10, Pages 1100: Impact of Rainwater Harvesting on the Drainage System: Case Study of a Condominium of Houses in Curitiba, Southern Brazil Water doi: 10.3390/w10081100 Authors: Andréa Teston Celimar Azambuja Teixeira Enedir Ghisi Ernani Benincá Cardoso The objective of this work is to assess the impact of rainwater use in single-family houses on drinking water consumption and on the urban drainage system by means of a case study of a condominium of houses in the city of Curitiba, southern Brazil. A quantitative evaluation of the rainwater volume used and spilled in the recovery system was carried out using two methods for sizing the rainwater tank capacity. Using daily rainfall data and three demand scenarios of water consumption, it was possible to verify the efficiency and reliability of the adopted systems. Furthermore, in order to verify the impact on drainage, the greatest rainfall in the series was assessed and then it was possible to measure it by comparing the hydrograph peak flows with and without the rainwater harvesting systems in the watershed outfall, corresponding to the storage tanks (concrete boxes) in the condominium. It was concluded that there was a decrease in the peak flow of 4.9% and 4.4%, respectively, in the two storage tanks evaluated when the rainwater tank capacities were estimated using the method based on the German Practical Method.

Description: Water, Vol. 10, Pages 1098: Exploring and Quantifying River Thermal Response to Heatwaves Water doi: 10.3390/w10081098 Authors: Sebastiano Piccolroaz Marco Toffolon Christopher Robinson Annunziato Siviglia Most of the existing literature on river water temperature focuseds on river thermal sensitivity to long-term trends of climate variables, whereas how river water temperature responds to extreme weather events, such as heatwaves, still requires in-depth analysis. Research in this direction is particularly relevant in that heatwaves are expected to increase in intensity, frequency, and duration in the coming decades, with likely consequences on river thermal regimes and ecology. In this study we analyzed the long-term temperature and streamflow series of 19 Swiss rivers with different hydrological regime (regulated, low-land, and snow-fed), and characterized how concurrent changes in air temperature and streamflow concurred to affect their thermal dynamics. We focused on quantifying the thermal response to the three most significant heatwave events that occurred in Central Europe since 1950 (July–August 2003, July 2006, and July 2015). We found that the thermal response of the analyzed rivers contrasted strongly depending on the river hydrological regime, confirming the behavior observed under typical weather conditions. Low-land rivers were extremely sensitive to heatwaves. In sharp contrast, high-altitude snow-fed rivers and regulated rivers receiving cold water from higher altitude hydropower reservoirs or diversions showed a damped thermal response. The results presented in this study suggest that water resource managers should be aware of the multiple consequences of heatwave events on river water temperature and incorporate expected thermal responses in adaptive management policy. In this respect, additional efforts and dedicated studies are required to deepen our knowledge on how extreme heatwave events can affect river ecosystems.

Description: Water, Vol. 10, Pages 1095: New Insights on Land Surface-Atmosphere Feedbacks over Tropical South America at Interannual Timescales Water doi: 10.3390/w10081095 Authors: Juan Mauricio Bedoya-Soto Germán Poveda David Sauchyn We present a simplified overview of land-atmosphere feedbacks at interannual timescales over tropical South America as structural sets of linkages among surface air temperature (T), specific humidity at 925 hPa (q925), volumetric soil water content (Θ), precipitation (P), and evaporation (E), at monthly scale during 1979–2010. Applying a Maximum Covariance Analysis (MCA), we identify the modes of greatest interannual covariability in the datasets. Time series extracted from the MCAs were used to quantify linear and non-linear metrics at up to six-month lags to establish connections among variables. All sets of metrics were summarized as graphs (Graph Theory) grouped according to their highest ENSO-degree association. The core of ENSO-activated interactions is located in the Amazon River basin and in the Magdalena-Cauca River basin in Colombia. Within the identified multivariate structure, Θ enhances the interannual connectivity since it often exhibits two-way feedbacks with the whole set of variables. That is, Θ is a key variable in defining the spatiotemporal patterns of P and E at interannual time-scales. For both the simultaneous and lagged analysis, T activates non-linear associations with q925 and Θ. Under the ENSO influence, T is a key variable to diagnose the dynamics of interannual feedbacks of the lower troposphere and soil interfaces over tropical South America. ENSO increases the interannual connectivity and memory of the feedback mechanisms.

Description: Water, Vol. 10, Pages 1096: Artificial Aquatic Ecosystems Water doi: 10.3390/w10081096 Authors: Chelsea C. Clifford James B. Heffernan As humans increasingly alter the surface geomorphology of the Earth, a multitude of artificial aquatic systems have appeared, both deliberately and accidentally. Human modifications to the hydroscape range from alteration of existing waterbodies to construction of new ones. The extent of these systems makes them important and dynamic components of modern landscapes, but their condition and provisioning of ecosystem services by these systems are underexplored, and likely underestimated. Instead of accepting that artificial ecosystems have intrinsically low values, environmental scientists should determine what combination of factors, including setting, planning and construction, subsequent management and policy, and time, impact the condition of these systems. Scientists, social scientists, and policymakers should more thoroughly evaluate whether current study and management of artificial aquatic systems is based on the actual ecological condition of these systems, or judged differently, due to artificiality, and consider resultant possible changes in goals for these systems. The emerging recognition and study of artificial aquatic systems presents an exciting and important opportunity for science and society.

Description: Water, Vol. 10, Pages 1097: Socio-Psychological Perspectives on the Potential for Serious Games to Promote Transcendental Values in IWRM Decision-Making Water doi: 10.3390/w10081097 Authors: Dianna Marini Wietske Medema Jan Adamowski Samuel P. L. Veissière Igor Mayer Arjen E. J. Wals Modern day challenges of water resource management involve difficult decision-making in the face of increasing complexity and uncertainty. However, even if all decision-makers possessed perfect knowledge, water management decisions ultimately involve competing values, which will only get more prominent with increasing scarcity and competition over resources. Therefore, an important normative goal for water management is long-term cooperation between stakeholders. According to the principles of integrated water resource management (IWRM), this necessitates that managerial decisions support social equity and intergenerational equity (social equity that spans generations). The purpose of this discussion is to formulate preliminary recommendations for the design of serious games (SGs), a potential learning tool that may give rise to shared values and engage stakeholders with conflicting interests to cooperate towards a common goal. Specifically, this discussion explores whether SGs could promote values that transcend self-interest (transcendental values), based on the contributions of social psychology. The discussion is organized in the following way. First, an introduction is provided as to why understanding values from psychological perspectives is both important for water management and a potential avenue for learning in SGs. Second, a review of the description of values and mechanisms of value change from the field of social psychology is presented. This review highlights key psychological constraints to learning or applying values. Based on this review, recommendations are made for SGs designers to consider when developing games for water management, in order to promote transcendental values. Overall, the main conclusions from exploring the potential of value change for IWRM through SGs design are as follows: 1-SGs design needs to consider how all values change systematically; 2-SGs design should incorporate the many value conflicts that are faced in real life water management, 3-SGs could potentially promote learning by having players reflect on the reasoning behind value priorities across water management situations, and 4-value change ought to be tested in an iterative SGs design process using the Schwartz’s Value Survey (SVS) (or something akin to it).

Description: Water, Vol. 10, Pages 1094: Effects of Erosion Control Works: Case Study—Grdelica Gorge, the South Morava River (Serbia) Water doi: 10.3390/w10081094 Authors: Stanimir Kostadinov Sonja Braunović Slavoljub Dragićević Miodrag Zlatić Nada Dragović Nikola Rakonjac The aim of this research was to analyse the changes in the soil erosion intensity caused by erosion control works (ECW) in Grdelica Gorge (The South Morava River) in the period between 1953 and 2016. For the purpose of quantifying the erosion intensity changes, the erosion potential model (EPM) was used to calculate the annual gross erosion (W), sediment transport (G), and erosion coefficient (Z) in the study area. As a result of the performed technical and biotechnical erosion control works, there was a general decreasing trend in the intensity of soil erosion processes in the last 63 years. The specific annual gross erosion in Grdelica Gorge was 1920.34 m3/km−2/year−1 in 1953, while in 2016 it was 492.42 m3/km−2/year−1. The specific sediment transport was 1421.05 m3/km−2/year−1 in 1953 and 364.39 m3/km−2/year−1 in 2016. Due to the changes in the intensity of erosion processes, the specific annual gross erosion in the study area decreased by 1427.92 m3/km−2/year−1 and the specific sediment transport by 1056.66 m3/km−2/year−1. The value of the erosion coefficient was reduced from Z = 0.84 in 1953 to Z = 0.32 in 2016. The results show that there is a significant correlation between the soil erosion intensity (erosion coefficient) and ECW (biotechnical works) performed in Grdelica Gorge. The permanent control of erosion processes in Grdelica Gorge is very important for torrential flood prevention and protection of two very important traffic routes (Belgrade-Skopje-Athens railway and motorway—Corridor X), as well as settlements, local roads, and other facilities in this area. Furthermore, these results are the basis for future water mana­gement projects, soil and environmental protection, spatial planning, agriculture, and other human activities.

Description: Water, Vol. 10, Pages 1090: Comparison of the Roles of Optimizing Root Distribution and the Water Uptake Function in Simulating Water and Heat Fluxes within a Maize Agroecosystem Water doi: 10.3390/w10081090 Authors: Fu Cai Yushu Zhang Huiqing Ming Na Mi Shujie Zhang Hui Zhang Yanbing Xie Xianli Zhao Roots are an important water transport pathway between soil and plant. Root water uptake (RWU) plays a key role in water and heat exchange between plants and the atmosphere. Inaccurate RWU schemes in land surface models are one crucial reason for decreased model performance. Despite some types of RWU functions being adopted in land surface models, none have been certified as suitable for maize farmland ecosystems. Based on 2007–2009 data observed at the maize agroecosystem field station in Jinzhou, China, the RWU function and root distribution (RD) in the Common Land Model (CoLM) were optimized and the effects of the optimizations on model performance were compared. Results showed that RD parameters calculated with root length density were more practical relative to root biomass in reflecting soil water availability, and they improved the simulation accuracy for water and heat fluxes. The modified RWU function also played a significant role in optimizing the simulation of water and heat fluxes. Similarly, the respective and integrated roles of two optimization schemes in improving CoLM performance were significant during continuous non-precipitation days, especially during the key water requirement period of maize. Notably, the improvements were restrained within a threshold of soil water content, and the optimizations were inoperative outside this threshold. Thus, the optimized RWU function and the revised RD introduced into the CoLM model are applicable for simulation of water and heat fluxes for maize farmland ecosystems in arid areas.

Description: Water, Vol. 10, Pages 1091: Characteristics and Practices of Ecological Flow in Rivers with Flow Reductions Due to Water Storage and Hydropower Projects in China Water doi: 10.3390/w10081091 Authors: Lejun Ma Xingnan Zhang Huan Wang Changjun Qi Water and flow reductions in the channels downstream of water storage and hydropower projects have significant impacts on aquatic ecosystems. Understanding and analyzing the ecosystem status is of great significance to facilitate the protection of riverine ecosystems. A database was established based on the 2000–2017 environmental impact assessment (EIA) reports on water storage and hydropower projects in China, and corresponding analysis software was built based on an ArcGIS spatial analysis platform. The projects in China are mainly found in the Yangtze and Pearl River basins and in south-western China. The hydropower projects have a larger influence than the water storage projects on the flow of downstream rivers sections, and most of the hydropower projects, especially the water diversion projects, cause flow reductions in the downstream rivers. An ecological flow management mechanism in China implemented in 2006 provided a promising method to alleviate river flow reductions. However, there is still only one kind of ecological flow calculation method and few ecological flow regulation measures in use. Based on the advantages and problems of the existing ecological flow management system, this paper proposes a management scheme based on a regional-engineering calculation method. The results can facilitate decision making in ecological flow management.

Description: Water, Vol. 10, Pages 1099: Combining Grey Relational Analysis and a Bayesian Model Averaging Method to Derive Monthly Optimal Operating Rules for a Hydropower Reservoir Water doi: 10.3390/w10081099 Authors: Guohua Fang Yuxue Guo Xianfeng Huang Martine Rutten Yu Yuan Various regression models are currently applied to derive functional forms of operating rules for hydropower reservoirs. It is necessary to analyze and evaluate the model selecting uncertainty involved in reservoir operating rules for efficient hydropower generation. Moreover, selecting the optimal input variables from a large number of candidates to characterize an output variable can lead to a more accurate operation simulation. Therefore, this paper combined the Grey Relational Analysis (GRA) method and the Bayesian Model Averaging (BMA) method to select input variables and derive the monthly optimal operating rules for a hydropower reservoir. The monthly input variables were first filtered according to the relationship between the preselected output and input variables based on the reservoir optimal deterministic trajectory using GRA. Three models, Particle Swarm Optimization-Least Squares Support Vector Machine (PSO-LSSVM), Adaptive Neural Fuzzy Inference System (ANFIS), and Multiple Linear Regression Analysis (MLRA) model, were further implemented to derive individual monthly operating rules. BMA was applied to determine the final monthly operating rules by analyzing the uncertainty of selecting individual models with different weights. A case study of Xinanjiang Reservoir in China shows that the combination of the two methods can achieve high-efficiency hydropower generation and optimal utilization of water resources.

Description: Water, Vol. 10, Pages 1107: Title Efficient Ammonium Removal by Bacteria Rhodopseudomonas Isolated from Natural Landscape Water: China Case Study Water doi: 10.3390/w10081107 Authors: Xuejiao Huang Jiupai Ni Chong Yang Mi Feng Zhenlun Li Deti Xie In this study, we isolated a strain of photosynthetic bacteria from landscape water located in Southwest University, Chongqing, China, and named it Smobiisys501. Smobiisys501 was Rhodopseudomonas sp. according to its cell morphological properties and absorption spectrum analysis of living cells. The analysis of the 16S rDNA amplification sequence with specific primers of photosynthetic bacteria showed that the homology between Smobiisys501 and Rhodopseudomonas sp. was 100%, and the alignment results of protein sequences of the bacterial chlorophyll Y subunit showed that Smobiisys501 and Rhodopseudomonas palustris were the most similar, with a similarity of more than 92%. However, Smobiisys501 could not utilize glucose and mannitol as a carbon source and had a low fatty acid content, which were different from the related strains of the genus Rhodopseudomonas. Moreover, the DNA-DNA relatedness was only 42.2 ± 3.3% between Smobiisys501 and the closest strain Rhodopseudomonas palustris. Smobiisys501 grew optimally at 30 °C and pH 7.0 in the presence of yeast extract, and it could efficiently remove ammonium (99.67% removal efficiency) from synthetic ammonium wastewater. All the results indicated that Smobiisys501 was a novel species of Rhodopseudomonas, with the ability to remove ammonium.

Description: Water, Vol. 10, Pages 1108: Sea Water Contamination in the Vicinity of the Italian Minor Islands Caused by Microplastic Pollution Water doi: 10.3390/w10081108 Authors: Giuseppe Andrea de Lucia Alvise Vianello Andrea Camedda Danilo Vani Paolo Tomassetti Stefania Coppa Luca Palazzo Marina Amici Giulia Romanelli Giorgio Zampetti Anna Maria Cicero Serena Carpentieri Stefania Di Vito Marco Matiddi The abundance and distribution of microplastics (MP) were evaluated in six “clean” sites (Italian minor islands) and in two “polluted” areas (near the mouth of two major Italian rivers). Samples of MP, plankton and persistent organic pollutants (POPs) were collected using a manta trawl (MA) and a plankton net (WP2), both lined with a 333 µm mesh net. MP have been confirmed to be ubiquitous since they were found at each site, showing an average density of 0.3 ± 0.04 items/m3 (values ranged from 0.641 to 0.119 ). When comparing the clean sites with the polluted ones, a significantly higher value of MP was found near the river mouths. The most common types of MP were synthetic filaments (50.24%), followed by fragments (30.39%), thin plastic films (16.98%) and spheres (2.39%). Infrared spectroscopy analysis highlighted that the most abundant polymers were polyethylene (PE-26%), polypropylene (PP-11%), polyethylene-terephthalate/polyester (PET/PEST-8%) and ethylene-vinyl-acetate (EVA-5%). Polychlorinated biphenyls and organochlorine pesticides were detected in all the samples with a high variability among sites and depths. This study adds to the existing information on the distribution of contaminants across the Mediterranean Sea, and is useful to policy makers who wish to implement effective measures to reduce MP pollution.

Description: Water, Vol. 10, Pages 1110: Multi-Objective Optimization of Resilient Design of the Multipurpose Reservoir in Conditions of Uncertain Climate Change Water doi: 10.3390/w10091110 Authors: Stanislav Paseka Zoran Kapelan Daniel Marton This paper presents and assesses a new approach to decision-making methods for the design of new reservoirs due in times of decreasing water resources. The methods used in this case are decision theory, Resilience and Robustness method. The methods have been selected primarily to analyze different design parameters of a new dam, mainly dam heights leading to different reservoir volumes. The study presents a novel approach to the optimal design of a multipurpose reservoir that would provide enough water for downstream environmental flow, residential and industrial water supply, agricultural water supply, and hydropower generation in the current conditions of climate uncertainty. Uncertainties are interpreted as possible future changes in the climate system using outputs from regional climatic models. In the case study, a simulation model was developed which is able to quantify long-term water balance and use this data to quantify resilience and robustness of its water supply. The simulation model was correlated to the GANetXL software in order to perform Genetic Algorithms based optimization of the reservoir’s operation. The simulation–optimization model was then applied to a real-life case study in the Czech Republic, in the Morava River Basin where a new dam with the multipurpose reservoir is planned to be built in the future. The results obtained in this way were analyzed in detail to identify the overall best solution consist of dam height and the total reservoir monthly outflow and new operational rules for the analyzed multipurpose reservoir.

Description: Water, Vol. 10, Pages 1109: Recent Changes in the Occurrences and Damages of Floods and Droughts in the United States Water doi: 10.3390/w10091109 Authors: Qianqian Zhou Guoyong Leng Jian Peng In this study, we compile and analyse 136,920 records of flood and 50,967 records of drought from a survey-based database to investigate recent changes in annual occurrence and economical cost in the United States. Results show that an average of 6520 floods has occurred per year during 1996–2016, with annual mean economic losses up to 3986 million US dollars, while 2427 drought events/year are recorded causing an average loss of 1684 million US dollars per year. Importantly, we found there is no evident changing tendency in annual economic damages of floods and droughts, despite an upward trend in their annual occurrences. This could be partly explained by changes in regional vulnerabilities, as indirectly reflected by the ratio of damaging events to total number of events experienced and the average damage per event. Spatially, vulnerability to droughts has decreased in most of the country, while increased vulnerability to floods is observed in a number of states. Despite limitations from the records and incomplete characterization of vulnerability, this study has great implications for targeted mitigation and adaptation, through identifying the regions that are most vulnerable to floods and droughts respectively and highlighting the contrasting patterns in regional vulnerability to floods and droughts.

Description: Water, Vol. 10, Pages 1125: Optimization-Based Agricultural Water-Saving Potential Analysis in Minqin County, Gansu Province China Water doi: 10.3390/w10091125 Authors: Qiong Yue Fan Zhang Ping Guo To deal with the contradictions that are caused by natural conditions and unreasonable water allocations in Minqin County, which are located downstream of the Shiyang River basin in arid northwest China, an optimization-based multi-scale calculation method was proposed for analyzing agricultural water-saving potential. Firstly, an optimization model was developed for allocating water and land resources legitimately with the conjunctive use of surface water and groundwater. Secondly, the groundwater equilibrium was fully considered in developing optimization model to achieve the ecological value of agricultural water savings. Then, multi-scale agricultural water-saving potentials were analyzed based on optimal results under different water-saving levels. These results provide local water managers with satisfactory economic benefit with higher water use efficiency. With reasonable management strategies of water and land resources, the ecosystem of Minqin County could gradually recover in the future. The results of the multi-scale water-saving potential analysis can help decision makers to identify desired water-saving plans that consider the coordinated development of the local economy, society, and ecology.

Description: Water, Vol. 10, Pages 1127: Towards a New Paradigm of Urban Water Infrastructure: Identifying Goals and Strategies to Support Multi-Benefit Municipal Wastewater Treatment Water doi: 10.3390/w10091127 Authors: Sasha Harris-Lovett Judit Lienert David L. Sedlak Over the past decade, water professionals have begun to focus on a new paradigm for urban water systems, which entails the recovery of resources from wastewater, the integration of engineered and natural systems, and coordination among agencies managing different facets of water systems. In the San Francisco Bay Area, planning for nutrient management serves as an exemplary model of this transition. We employed a variety of methodological approaches including stakeholder analysis, multi-criteria decision-making weight elicitation, and document analysis to understand and support decision-making in this context. Based on interviews with 32 stakeholders, we delineate goals that are considered to be important for achieving the new paradigm and we highlight management strategies that can help reach these goals. We identify and analyze the social, institutional, and technical impediments to planning and implementing multi-benefit wastewater infrastructure projects and identify strategies to overcome some of these challenges. Transitioning to a new paradigm for urban water infrastructure will require stakeholders to proactively forge collaborative relationships, jointly define a shared vision and objectives, and build new rules to overcome limitations of current institutional policies.

Description: Water, Vol. 10, Pages 1121: Intensity and Persistence of Soil Water Repellency in Pine Forest Soil in a Temperate Continental Climate under Drought Conditions Water doi: 10.3390/w10091121 Authors: Edyta Hewelke Lidia Oktaba Dariusz Gozdowski Marek Kondras Izabella Olejniczak Ewa Beata Górska Although soil water repellency (SWR) has been reported under different soils, climates, and vegetation types of the world, especially in forest land and following wildfires, the understanding of this variable continues to be rather limited. This study presented the characterization of SWR from wild fire measurements in a Scots pine Peucedano-Pinetum forest in the Kampinos National Park (central Poland), which is characterized by a temperate continental climate. The main objectives were: [i] To evaluate the potential occurrence, intensity, and persistence of soil water repellency in the surface layers of podzolized rusty soils during a dry summer; [ii] to determine whether a wildfire increased SWR, compared to the unburnt condition of soil; and [iii] to identify changes in hydrophobicity 13 months after a fire. The Water Drop Penetration Time (WDPT) test was used to assess persistence and intensity of soil SWR. Hydrophobicity is a natural phenomenon during periods of drought in temperate continental climates. The extreme class of SWR was observed in surface layers of up to 20 cm. A higher hydrophobicity was noted in the older habitats of the Peucedano-Pinetum forest. Maximum WDPT values (10,800 s) were found for an older ecosystem cover, during a dry summer. SWR in fire-affected soils is dependent on the intensity of the fire, as well as displaying spatial and seasonal variability. Thirteen months after a fire, the highest variability in the occurrence of non-wettability, was recorded in the surface layers of areas affected by a weak fire. A positive relationship between soil pH and WDPT values was determined to a 20 cm depth. Prolonged dry periods resulting from global climate change, may enhance the effects of increasing SWR; it therefore seems reasonable for future research on biosphere–climate interactions, to take the presence of hydrophobicity into account.

Description: Water, Vol. 10, Pages 1118: Irrigation Governance in Developing Countries: Current Problems and Solutions Water doi: 10.3390/w10091118 Authors: Enrique Playán Juan Antonio Sagardoy Rosendo Castillo The evolution of water governance and societal perception in large, public irrigation systems in developing countries has triggered successive waves of reforms since the 1980s. Among them are Participatory Irrigation Management, Irrigation Management Transfer, Public-Private Partnerships or Market Instruments. Reforms have generalized the implementation of Water Users Associations (WUAs) in continuous interaction with a public Irrigation Agency. This paper set out to review recurrent problems and reported solutions in the governance of irrigated areas in developing countries and to relate solutions to problems in a case study context. The combination of literature review and the experience of the authors permitted identification and characterization of eight problems and eight solutions. A semi-quantitative approach was designed to relate solutions to problems in case study WUAs. The approach is based on the definition of a generic problem-solution matrix and a WUA-specific problem vector. The solution vector indicates the adequacy of each solution to a case study WUA. It can be obtained by multiplying the problem vector with the problem-solution matrix. Application of this approach to seven case study WUAs demonstrated its potential. Local fine-tuning of the coefficients defining the problem-solution matrix seems required to draw conclusions effectively guiding decision-making.