Description: Water, Vol. 10, Pages 18: Commemorating Dr. Gudmundur “Bo” Bodvarsson (1951–2006), a Leader of the Deep Unsaturated Flow and Transport Investigations Water doi: 10.3390/w10010018 Authors: Chin-Fu Tsang Marcelo Lippmann Patrick Dobson Yvonne Tsang Boris Faybishenko Sally Benson Jens Birkholzer Stefan Finsterle Daniel Hawkes Susan Hubbard Timothy Kneafsey Hui-Hai Liu Curtis Oldenburg Karsten Pruess Eric Sonnenthal Maryann Villavert Joseph Wang Yu-Shu Wu Robert Zimmerman The Special Issue “Water and Solute Transport in Vadose Zone” in the journal Water is dedicated to the memory of Dr. Gudmundur “Bo” Bodvarsson, the former director of the Earth Sciences Division of Lawrence Berkeley National Laboratory (http://eesa.lbl.gov/profiles/gudmundur-bo-sbodvarsson/).[...]

Description: Water, Vol. 10, Pages 23: Integrated Assessment of Shallow-Aquifer Vulnerability to Multiple Contaminants and Drinking-Water Exposure Pathways in Holliston, Massachusetts Water doi: 10.3390/w10010023 Authors: Birgit Claus Henn Yelena Ogneva-Himmelberger Allegra Denehy Marcie Randall Nichole Cordon Bilin Basu Brian Caccavale Stefanie Covino Ravi Hanumantha Kevin Longo Ariel Maiorano Spring Pillsbury Gabrielle Rigutto Kelsey Shields Marianne Sarkis Timothy Downs Half of U.S. drinking water comes from aquifers, and very shallow ones (<20 feet to water table) are especially vulnerable to anthropogenic contamination. We present the case of Holliston, a Boston, Massachusetts suburb that draws its drinking water from very shallow aquifers, and where metals and solvents have been reported in groundwater. Community concerns focus on water discolored by naturally occurring manganese (Mn), despite reports stating regulatory aesthetic compliance. Epidemiologic studies suggest Mn is a potentially toxic element (PTE) for children exposed by the drinking-water pathway at levels near the regulatory aesthetic level. We designed an integrated, community-based project: five sites were profiled for contaminant releases; service areas for wells were modeled; and the capture zone for one vulnerable well was estimated. Manganese, mercury, and trichloroethylene are among 20 contaminants of interest. Findings show that past and/or current exposures to multiple contaminants in drinking water are plausible, satisfying the criteria for complete exposure pathways. This case questions the adequacy of aquifer protection and monitoring regulations, and highlights the need for integrated assessment of multiple contaminants, associated exposures and health risks. It posits that community-researcher partnerships are essential for understanding and solving complex problems.

Description: Water, Vol. 10, Pages 22: Emptying Operation of Water Supply Networks Water doi: 10.3390/w10010022 Authors: Oscar Coronado-Hernández Vicente Fuertes-Miquel Fredy Angulo-Hernández Recently, emptying processes have been studied in experimental facilities in pipelines, but there is a lack regarding applications in actual pipelines, which permits establishing the risk of collapse because of sub-atmospheric pressure occurrence. This research presents a mathematical model to simulate the emptying process of water supply networks, and the application to a water emptying pipeline with nominal diameter of 1000 mm and 578 m long which is located on the southern of Cartagena, Bolívar Deparment, Colombia. In the application, both pipes and the air valve data manufacturer were considered. The behavior of all hydraulic and thermodynamic variables is considered. Results show that is crucial to know sub-atmospheric pressure values to prevent the collapse of the pipeline. The application of the mathematical model confirms that the hydraulic system is well designed depending on air valve sizes and maneuvering of drain valve.

Description: Water, Vol. 10, Pages 24: Regionalization of Drought across South Korea Using Multivariate Methods Water doi: 10.3390/w10010024 Authors: Muhammad Azam Hyung Park Seung Maeng Hyung Kim Topographic and hydro-climatic features of South Korea are highly heterogeneous and able to influence the drought phenomena in the region. The complex topographical and hydro-climatic features of South Korea need a statistically accurate method to find homogeneous regions. Regionalization of drought in a bivariate framework has scarcely been applied in South Korea before. Hierarchical Classification on Principal Components (HCPC) algorithm together with Principal Component Analysis (PCA) method and cluster validation indices were investigated and used for the regionalization of drought across the South Korean region. Statistical homogeneity and discordancy of the region was tested on univariate and bivariate frameworks. HCPC indicate that South Korea should be divided into four regions which are closer to being homogeneous. Univariate and bivariate homogeneity and discordancy tests showed the significant difference in their results due to the inability of univariate homogeneity and discordancy measures to consider the joint behavior of duration and severity. Regionalization of drought for SPI time scale of 1, 3, 6, 12, and 24 months showed significant variation in discordancy and homogeneity of the region with the change in SPI time scale. The results of this study can be used as basic data required to establish a drought mitigation plan on regional scales.

Description: Water, Vol. 10, Pages 25: Hydrologic Evaluation of Six High Resolution Satellite Precipitation Products in Capturing Extreme Precipitation and Streamflow over a Medium-Sized Basin in China Water doi: 10.3390/w10010025 Authors: Shanhu Jiang Shuya Liu Liliang Ren Bin Yong Linqi Zhang Menghao Wang Yujie Lu Yingqing He Satellite precipitation products (SPPs) are critical data sources for hydrological prediction and extreme event monitoring, especially for ungauged basins. This study conducted a comprehensive hydrological evaluation of six mainstream SPPs (i.e., TMPA 3B42RT, CMORPH-RT, PERSIANN-RT, TMPA 3B42V7, CMORPH-CRT, and PERSIANN-CDR) over humid Xixian basin in central eastern China for a period of 14 years (2000–2013). The evaluation specifically focused on the performance of the six SSPs in capturing precipitation and streamflow extremes. Results show that the two post-real-time research products of TMPA 3B42V7 and CMORPH-CRT exhibit much better performance than that of their corresponding real-time SPPs for precipitation estimation at daily and monthly time scales. By contrast, the newly released post-real-time research product PERSIANN-CDR insignificantly improves precipitation estimates compared with the real-time PERSIANN-RT does at daily time scale. The daily streamflow simulation of TMPA 3B42V7 fits best with the observed streamflow series among those of the six SPPs. The three month-to-month gauge-adjusted post-real-time research products can simulate acceptable monthly runoff series. TMPA 3B42V7 and CMORPH-CRT present good performance in capturing precipitation and streamflow extremes, although they still exhibit non-ignorable deviation and occurrence time inconsistency problems compared with gauge-based results. Caution should be observed when using the current TMPA, CMORPH, and PERSIANN products for monitoring and predicting extreme precipitation and flood at such medium-sized basin. This work will be valuable for the utilization of SPPs in extreme precipitation monitoring, streamflow forecasting, and water resource management in other regions with similar climate and topography characteristics.

Description: Water, Vol. 10, Pages 20: Studying Operation Rules of Cascade Reservoirs Based on Multi-Dimensional Dynamics Programming Water doi: 10.3390/w10010020 Authors: Zhiqiang Jiang Hui Qin Wenjie Wu Yaqi Qiao Although many optimization models and methods are applied to the optimization of reservoir operation at present, the optimal operation decision that is made through these models and methods is just a retrospective review. Due to the limitation of hydrological prediction accuracy, it is practical and feasible to obtain the suboptimal or satisfactory solution by the established operation rules in the actual reservoir operation, especially for the mid- and long-term operation. In order to obtain the optimized sample data with global optimality; and make the extracted operation rules more reasonable and reliable, this paper presents the multi-dimensional dynamic programming model of the optimal joint operation of cascade reservoirs and provides the corresponding recursive equation and the specific solving steps. Taking Li Xianjiang cascade reservoirs as a case study, seven uncertain problems in the whole operation period of the cascade reservoirs are summarized after a detailed analysis to the obtained optimal sample data, and two sub-models are put forward to solve these uncertain problems. Finally, by dividing the whole operation period into four characteristic sections, this paper extracts the operation rules of each reservoir for each section respectively. When compared the simulation results of the extracted operation rules with the conventional joint operation method; the result indicates that the power generation of the obtained rules has a certain degree of improvement both in inspection years and typical years (i.e., wet year; normal year and dry year). So, the rationality and effectiveness of the extracted operation rules are verified by the comparative analysis.

Description: Water, Vol. 10, Pages 21: Rheological Modeling of Macro Viscous Flows of Granular Suspension of Regular and Irregular Particles Water doi: 10.3390/w10010021 Authors: Anna Pellegrino Leonardo Schippa This paper refers to complex granular-fluid mixtures involved into geophysical flows, such as debris and hyper-concentrated flows. For such phenomena, the interstitial fluids play a role when they are in the viscous regime. Referring to experiments on granular-fluid mixture carried out with pressure imposed annular shear cell, we study the rheological behaviour of dense mixture involving both spheres and irregular-shaped particles. For the case of viscous suspensions with irregular grains, a significant scatter of data from the trend observed for mixtures with spherical particles was evident. In effect, the shape of the particles likely plays a fundamental role in the flow dynamics, and the constitutive laws proposed by the frictional theory for the spheres are no longer valid. Starting from the frictional approach successfully applied to suspension of spheres, we demonstrate that also in case of irregular particles the mixture rheology may be fully characterized by the two relationships involving friction coefficient µ and volume concentration Ф as a function of the dimensionless viscous number Iv. To this goal, we provided a new consistent general model, referring to the volume fraction law and friction law, which accounts for the particle shape. In this way, the fitting parameters reduce just to the static friction angle µ1, and the two parameters, k and fs related to the grain shape. The resulting general model may apply to steady fully developed flows of saturated granular fluid mixture in the viscous regime, no matter of granular characteristics.

Description: Water, Vol. 10, Pages 19: Estimation of Irrigation Water Demand and Economic Returns of Water in Zhangye Basin Water doi: 10.3390/w10010019 Authors: Tianhe Sun Qiuqiong Huang Jinxia Wang The objective of this study is to provide estimates of price elasticities of irrigation water demands in Zhangye Basin (ZB), an inland river basin in China, with the most recent data and to compare the values of marginal product (VMPs) of water to the prices of water farmers are currently paying. With a set of village and household survey data collected in 2009 and 2014, household fixed effects models are used to estimate water demand and crop production functions. The estimation results are then used to estimate price elasticities and VMPs. Results show that demands for surface water, groundwater, and conjunctive irrigation water are all in the inelastic range. The results imply that water prices may need to be increased significantly to induce sizable water savings. Another significant finding is that for a large share of the sample households, VMPs of water are higher than the prices of water. The estimated VMPs provide policy makers with some guidelines on the minimum level of water prices required to achieve any water savings among those households.

Description: Water, Vol. 10, Pages 17: Non-Point Source Nitrogen and Phosphorus Assessment and Management Plan with an Improved Method in Data-Poor Regions Water doi: 10.3390/w10010017 Authors: Xuekai Chen Xiaobo Liu Wenqi Peng Fei Dong Zhihua Huang Ruonan Wang To enhance the quantitative simulation and integrated assessment of non-point source (NPS) pollution in plateau lakes in data-poor regions, a simple and practical NPS assessment method is developed by combining the improved export coefficient model (ECM) and the revised universal soil loss equation (RUSLE). This method is evaluated via application to the Chenghai Lake watershed (Yunnan Province, China), which contains a typical plateau lake. The estimated results reflect the actual situation within the watershed. The total nitrogen (TN) and total phosphorus (TP) loads in the study area in 2014 were 360.35 t/a (44.30% dissolved nitrogen (DN) and 55.70% adsorbed nitrogen (AN)) and 86.15 t/a (71.40% adsorbed phosphorus (AP)), respectively. The southern and eastern portions of the watershed are key regions for controlling dissolved and adsorbed pollutants, respectively. Soil erosion and livestock are the main TN and TP pollution sources in the study area and should be controlled first. Additionally, reasonable and practical suggestions are proposed to minimize water pollution according to a scenario analysis. The method in this study provides a foundation for scientific theories that can be used in water resources protection planning and the method can be applied to the NPS assessment of similar regions with scarce data.

Description: Water, Vol. 10, Pages 16: Variability and Trend Detection in the Sediment Load of the Upper Indus River Water doi: 10.3390/w10010016 Authors: Sardar Ateeq-Ur-Rehman Minh Bui Peter Rutschmann Water reservoirs planned or constructed to meet the burgeoning energy and irrigation demands in Pakistan face a significant loss of storage capacity due to heavy sediment load from the upper Indus basin (UIB). Given their importance and the huge investment, assessments of current UIB sediment load and possible future changes are crucial for informed decisions on planning of optimal dams’ operation and ensuring their prolonged lifespan. In this regard, the daily suspended sediment loads (SSLs) and their changes are analyzed for the meltwater-dominated zone up to the Partab Bridge and the whole UIB up to Besham Qila, which is additionally influenced by monsoonal rainfall. The gaps between intermittent suspended sediment concentration (SSC) samples are filled by wavelet neural networks (WA-ANNs) using discharges for each site. The temporal dynamics of SSLs and discharges are analyzed using a suite of three non-parametric trend tests while the slope is identified using Sen’s slope estimator. We found disproportional spatio-temporal trends between SSLs and discharges caused primarily by intra-annual shifts in flows, which can lead to increased trap efficiency in planned reservoirs, especially upstream of Besham Qila. Moreover, a discernible increase in SSLs recorded at Partab Bridge during summer is being deposited downstream in the river channel. This is due to a decrease in river transport capacity in the monsoonal zone. These findings will not only help to identify these morphological problems, but also accurately anticipate the spatio-temporal changes in the sediment budget of the upper Indus River. Our results will help improve reservoir operational rules and sediment management strategies for existing and 30,000-MW planned dams in the UIB.