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Water, Volume 7, Issue 7 (July 2015) , Pages 3166-4025

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Open AccessArticle
Defining an Ecologically Ideal Shallow Groundwater Depth for Regional Sustainable Management: Conceptual Development and Case Study on the Sanjiang Plain, Northeast China
Water 2015, 7(7), 3997-4025; https://doi.org/10.3390/w7073997 - 21 Jul 2015
Cited by 7 | Viewed by 2265
Abstract
The depth and fluctuation of shallow groundwater influence water supply to land surface vegetation. Knowledge of an ecologically ideal depth range of shallow groundwater for a vegetation ecosystem can be crucial for sustainability of regional water resource management and ecological conservation. In this [...] Read more.
The depth and fluctuation of shallow groundwater influence water supply to land surface vegetation. Knowledge of an ecologically ideal depth range of shallow groundwater for a vegetation ecosystem can be crucial for sustainability of regional water resource management and ecological conservation. In this study, we developed a conceptual model that identifies an upper and a lower boundary of shallow groundwater for sustaining present vegetation ecosystems, termed ecologically ideal shallow groundwater depth (EISGD). We then applied the conceptual model to the Sanjiang Plain (10.9 × 104 km2) in northeast China in order to gain insights into sustainable shallow groundwater usage in this intensively irrigated agricultural region. Using soil capillary rise, plant rooting depth, extinction depth, and the actual groundwater depth, we identified an upper boundary range of EISGD between 0.5 and 2.8 m and a lower boundary range of EISGD between 2.0 and 14.3 m for different vegetation covers in the Sanjiang Plain. Based on the ranges, we estimated allowable shallow groundwater withdrawal (i.e., without degrading the present vegetation ecosystem) for the region and identified an area of 2.54 × 1010 m2 with a total of 9.14 × 108 m3 water deficit. Currently, the entire Sanjiang Plain has a total volume of 45.30 × 108 m3 EISGD allowable shallow groundwater withdrawal, thus the plain’s northeast region can be considered as having a high allowable pumping capacity. This study demonstrates that application of an EISGD concept can be useful for developing regional management strategies and plans for ecological protection and sustainable groundwater utilization. Full article
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Open AccessArticle
Groundwater Modeling as an Alternative Approach to Limited Data in the Northeastern Part of Mt. Hermon (Syria), to Develop a Preliminary Water Budget
Water 2015, 7(7), 3978-3996; https://doi.org/10.3390/w7073978 - 21 Jul 2015
Cited by 5 | Viewed by 2657
Abstract
In developing countries such as Syria, the lack of hydrological data affects groundwater resource assessment. Groundwater models provide the means to fill the gaps in the available data in order to improve the understanding of groundwater systems. The study area can be considered [...] Read more.
In developing countries such as Syria, the lack of hydrological data affects groundwater resource assessment. Groundwater models provide the means to fill the gaps in the available data in order to improve the understanding of groundwater systems. The study area can be considered as the main recharge area of the eastern side of Barada and Awaj basin in the eastern part of Mt. Hermon. The withdrawal for agricultural and domestic purposes removes a considerable amount of water. The steady-state three-dimensional (3D) groundwater model (FEFLOW which is an advanced finite element groundwater flow and transport modeling tool), was used to quantify groundwater budget components by using all available data of hydrological year 2009–2010. The results obtained may be considered as an essential tool for groundwater management options in the study area. The calibrated model demonstrates a good agreement between the observed and simulated hydraulic head. The result of the sensitivity analysis shows that the model is highly sensitive to hydraulic conductivity changes and sensitive to a lesser extent to water recharge amount. Regarding the upper aquifer horizon, the water budget under steady-state condition indicates that the lateral groundwater inflow from the Jurassic aquifer into this horizon is the most important recharge component. The major discharge component from this aquifer horizon occurs at its eastern boundary toward the outside of the model domain. The model was able to produce a satisfying estimation of the preliminary water budget of the upper aquifer horizon which indicates a positive imbalance of 4.6 Mm3·y−1. Full article
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Open AccessArticle
Parameter Automatic Calibration Approach for Neural-Network-Based Cyclonic Precipitation Forecast Models
Water 2015, 7(7), 3963-3977; https://doi.org/10.3390/w7073963 - 17 Jul 2015
Cited by 9 | Viewed by 1990
Abstract
This paper presents artificial neural network (ANN)-based models for forecasting precipitation, in which the training parameters are adjusted using a parameter automatic calibration (PAC) approach. A classical ANN-based model, the multilayer perceptron (MLP) neural network, was used to verify the utility of the [...] Read more.
This paper presents artificial neural network (ANN)-based models for forecasting precipitation, in which the training parameters are adjusted using a parameter automatic calibration (PAC) approach. A classical ANN-based model, the multilayer perceptron (MLP) neural network, was used to verify the utility of the proposed ANN–PAC approach. The MLP-based ANN used the learning rate, momentum, and number of neurons in the hidden layer as its major parameters. The Dawu gauge station in Taitung, Taiwan, was the study site, and observed typhoon characteristics and ground weather data were the study data. The traditional multiple linear regression model was selected as the benchmark for comparing the accuracy of the ANN–PAC model. In addition, two MLP ANN models based on a trial-and-error calibration method, ANN–TRI1 and ANN–TRI2, were realized by manually tuning the parameters. We found the results yielded by the ANN–PAC model were more reliable than those yielded by the ANN–TRI1, ANN–TRI2, and traditional regression models. In addition, the computing efficiency of the ANN–PAC model decreased with an increase in the number of increments within the parameter ranges because of the considerably increased computational time, whereas the prediction errors decreased because of the model’s increased capability of identifying optimal solutions. Full article
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Open AccessArticle
Optimizing Dredge-and-Dump Activities for River Navigability Using a Hydro-Morphodynamic Model
Water 2015, 7(7), 3943-3962; https://doi.org/10.3390/w7073943 - 17 Jul 2015
Cited by 13 | Viewed by 2197
Abstract
Worldwide, significant dredging activities of riverbed sediment are employed to ensure that freight transportation on rivers can continue year-round. Imbalances of sediment budget may produce relevant impacts regarding river morphology and related environmental services. This study shows that hydro-morphodynamic modeling tools can be [...] Read more.
Worldwide, significant dredging activities of riverbed sediment are employed to ensure that freight transportation on rivers can continue year-round. Imbalances of sediment budget may produce relevant impacts regarding river morphology and related environmental services. This study shows that hydro-morphodynamic modeling tools can be used to optimize dredge-and-dump activities and, at the same time, mitigate problems deriving from these activities in rivers. As a case study, we focused on dredging activities on the Lower Parana River, Argentina. Navigation on this river is of crucial importance to the economies of the bordering countries, hence, each year significant dredging activities are employed. To estimate dredging loads under different strategies, a 25 km river reach of the Parana River was modeled using the Delft3D-modelling suite by Deltares. The Netherlands, to simulate flow-sediment interactions in a quasi-steady and uncoupled approach. Impacts of dredging activities were explicitly included. Different dredge-and-dump strategies included variations in dredging over-depth (clearance) and variations in dumping locations. Our results indicate that dredge-and-dump strategies can be targeted to stimulate natural processes that improve the depth and stability of the navigation channel and to counteract unwanted bed level responses in the long-medium term. A ~40% reduction in dredging effort could be achieved by moving the dredged material to distant locations in the secondary channel rather than dumping to the side of the waterway in the main channel. Full article
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Open AccessArticle
Partial Least Squares Regression for Determining the Control Factors for Runoff and Suspended Sediment Yield during Rainfall Events
Water 2015, 7(7), 3925-3942; https://doi.org/10.3390/w7073925 - 14 Jul 2015
Cited by 6 | Viewed by 1959
Abstract
Multivariate statistics are commonly used to identify the factors that control the dynamics of runoff or sediment yields during hydrological processes. However, one issue with the use of conventional statistical methods to address relationships between variables and runoff or sediment yield is multicollinearity. [...] Read more.
Multivariate statistics are commonly used to identify the factors that control the dynamics of runoff or sediment yields during hydrological processes. However, one issue with the use of conventional statistical methods to address relationships between variables and runoff or sediment yield is multicollinearity. The main objectives of this study were to apply a method for effectively identifying runoff and sediment control factors during hydrological processes and apply that method to a case study. The method combines the clustering approach and partial least squares regression (PLSR) models. The case study was conducted in a mountainous watershed in the Three Gorges Area. A total of 29 flood events in three hydrological years in areas with different land uses were obtained. In total, fourteen related variables were separated from hydrographs using the classical hydrograph separation method. Twenty-nine rainfall events were classified into two rainfall regimes (heavy Rainfall Regime I and moderate Rainfall Regime II) based on rainfall characteristics and K-means clustering. Four separate PLSR models were constructed to identify the main variables that control runoff and sediment yield for the two rainfall regimes. For Rainfall Regime I, the dominant first-order factors affecting the changes in sediment yield in our study were all of the four rainfall-related variables, flood peak discharge, maximum flood suspended sediment concentration, runoff, and the percentages of forest and farmland. For Rainfall Regime II, antecedent condition-related variables have more effects on both runoff and sediment yield than in Rainfall Regime I. The results suggest that the different control factors of the two rainfall regimes are determined by the rainfall characteristics and thus different runoff mechanisms. Full article
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Open AccessArticle
Experimenting with Coupled Hydro-Ecological Models to Explore Measure Plans and Water Quality Goals in a Semi-Enclosed Swedish Bay
Water 2015, 7(7), 3906-3924; https://doi.org/10.3390/w7073906 - 14 Jul 2015
Cited by 6 | Viewed by 2330
Abstract
Measure plans are currently being developed for the Water Framework Directive (WFD) by European water authorities. In Sweden, such plans include measures for good ecological status in the coastal ecosystem. However, the effect of suggested measures is not yet known. We therefore experimented [...] Read more.
Measure plans are currently being developed for the Water Framework Directive (WFD) by European water authorities. In Sweden, such plans include measures for good ecological status in the coastal ecosystem. However, the effect of suggested measures is not yet known. We therefore experimented with different nutrient reduction measures on land and in the sea, using a model system of two coupled dynamic models for a semi-enclosed bay and its catchment. The science question was whether it is worthwhile to implement measures in the local catchment area to reach local environmental goals, or if the status of the Bay is more governed by the water exchange with the Sea. The results indicate that by combining several measures in the catchment, the nutrient load can be reduced by 15%–20%. To reach the same effect on nutrient concentrations in the Bay, the concentrations of the sea must be reduced by 80%. Hence, in this case, local measures have a stronger impact on coastal water quality. The experiment also show that the present targets for good ecological status set up by the Swedish water authorities may be unrealistic for this Bay. Finally, we discuss when and how to use hydro-ecological models for societal needs. Full article
(This article belongs to the Special Issue Hydro-Ecological Modeling) Printed Edition available
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Open AccessArticle
Review of Risk Status of Groundwater Supply Wells by Tracing the Source of Coliform Contamination
Water 2015, 7(7), 3878-3905; https://doi.org/10.3390/w7073878 - 14 Jul 2015
Cited by 4 | Viewed by 1646
Abstract
Coliform source tracking was undertaken on 48 water sources of which 42 are potable in 26 water supply systems spread across South Australia. The water sources in the study vary from unprotected springs in creek beds to deep confined aquifers. The frequency analysis [...] Read more.
Coliform source tracking was undertaken on 48 water sources of which 42 are potable in 26 water supply systems spread across South Australia. The water sources in the study vary from unprotected springs in creek beds to deep confined aquifers. The frequency analysis of historical coliform detections indicate that aquifer types, depth to water and casing depth are important considerations; whilst maintaining well integrity and the presence of low permeable clay layers above the production zone are the dominant parameters for minimizing coliform contamination of water supply wells. However, in karst and fractured rock aquifers, pathways for coliform transport exist, as evidenced in the >200 MPN/100 mL level of coliform detection. Data indicate that there is no compelling evidence to support the contention that the wells identified as low risk are contaminated through geological strata and clay barriers. However, data strongly supports the suggestion that coliform detection from sample taps and wellheads stem from the surrounding groundwater and soil-plant sources as a result of failed well integrity, or potentially from coliform bacteria that can persist within biofilms formed on well casings, screens, pump columns and pumps. Coliform sub-typing results show that most coliform bacteria detected in town water supply wells are associated with the soil-water-plant system and are ubiquitous in the environment: Citrobacter spp. (65%), Enterobacter spp. (63%), Pantoea spp. (17%), Serratia spp. (19%), Klebsiella spp. (34%), and Pseudomonas spp. (10%). Overall, 70% of wells harbor detectable thermotolerant coliforms (TTC) with potentially 36% of species of animal origin, including Escherichia coli species found in 12% of wells. Full article
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Open AccessArticle
Comparative Analysis of Water Quality between the Runoff Entrance and Middle of Recycling Irrigation Reservoirs
Water 2015, 7(7), 3861-3877; https://doi.org/10.3390/w7073861 - 14 Jul 2015
Cited by 6 | Viewed by 2524
Abstract
Recycling irrigation reservoirs (RIRs) are an emerging aquatic ecosystem of critical importance, for conserving and protecting increasingly scarce water resources. Here, we compare water quality between runoff entrance and middle of four RIRs in nurseries in Virginia (VA) and Maryland (MD). Surface water [...] Read more.
Recycling irrigation reservoirs (RIRs) are an emerging aquatic ecosystem of critical importance, for conserving and protecting increasingly scarce water resources. Here, we compare water quality between runoff entrance and middle of four RIRs in nurseries in Virginia (VA) and Maryland (MD). Surface water temperature (T) and oxidation-reduction potential (ORP) were lower in the middle than at the entrance, while the trend was opposite for dissolved oxygen (DO), pH and chlorophyll a (Chla). The magnitude of these differences between the entrance and middle decreased with increasing depth. These differences were magnified by water stratification from April to October. Minimum differences were observed for electrical conductivity (EC), total dissolved solids (TDS) and turbidity (TUR). Cluster analyses were performed on water quality difference data to evaluate whether the differences vary with respect to reservoirs. Two clusters were formed with one consisting primarily of VA reservoirs, and the other consisting mostly of MD reservoirs in both years. Water quality in the middle and at the entrance of RIRs was expected to vary greatly because of runoff inflow. The two-point water quality differences observed here, although statistically significant, are not large enough to cause significant impact on crop health and productivity for most water quality parameters except pH. Additional analysis of outlet data shows that the range and magnitude of water quality difference between the middle and the outlet are comparable to those between the middle and entrance of RIRs. These results indicate that monitoring at a single point is sufficient to obtain reliable water quality estimates for most water quality parameters in RIRs except pH. This is important when considering the cost of labor and equipment necessary for documenting water quality in agricultural production systems. However, additional pH measurements are still necessary to make practical water quality management decisions. Full article
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Open AccessArticle
Flood Risk Management in Remote and Impoverished Areas—A Case Study of Onaville, Haiti
Water 2015, 7(7), 3832-3860; https://doi.org/10.3390/w7073832 - 14 Jul 2015
Cited by 12 | Viewed by 4933
Abstract
In this study, geographic information system (GIS)-based hydrologic and hydraulic modeling was used to perform a flood risk assessment for Onaville, which is a fairly new, rapidly growing informal settlement that is exposed to dangerous flash-flood events. Since records of historic floods did [...] Read more.
In this study, geographic information system (GIS)-based hydrologic and hydraulic modeling was used to perform a flood risk assessment for Onaville, which is a fairly new, rapidly growing informal settlement that is exposed to dangerous flash-flood events. Since records of historic floods did not exist for the study area, design storms with a variety of significant average return intervals (ARIs) were derived from intensity-duration-frequency (IDF) curves and transformed into design floods via rainfall-runoff modeling in hydrologic engineering center’s hydrologic modeling system (HEC-HMS). The hydraulic modeling software hydrologic engineering center’s river analysis system (HEC-RAS) was used to perform one-dimensional, unsteady-flow simulations of the design floods in the Ravine Lan Couline, which is the major drainage channel of the area. Topographic data comprised a 12 m spatial resolution TanDEM-X digital elevation model (DEM) and a 30 cm spatial resolution DEM created with mapping drones. The flow simulations revealed that large areas of the settlement are currently exposed to flood hazard. The results of the hydrologic and hydraulic modeling were incorporated into a flood hazard map which formed the basis for flood risk management. We present a grassroots approach for preventive flood risk management on a community level, which comprises the elaboration of a neighborhood contingency plan and a flood risk awareness campaign together with representatives of the local community of Onaville. Full article
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Open AccessArticle
Desalination of Water Using ZVI (Fe0)
Water 2015, 7(7), 3671-3831; https://doi.org/10.3390/w7073671 - 14 Jul 2015
Cited by 15 | Viewed by 4638
Abstract
Batch treatment of water (0.2 to 240 L) using Fe0 (44,000–77,000 nm) in a diffusion environment operated (at −8 to 25 °C) using: (a) no external energy; (b) pressurized (<0.1 MPa) air; (c) pressurized (<0.1 MPa) acidic gas (CO2); (d) [...] Read more.
Batch treatment of water (0.2 to 240 L) using Fe0 (44,000–77,000 nm) in a diffusion environment operated (at −8 to 25 °C) using: (a) no external energy; (b) pressurized (<0.1 MPa) air; (c) pressurized (<0.1 MPa) acidic gas (CO2); (d) pressurized (<0.1 MPa) anoxic gas (N2); (e) pressurized (<0.1 MPa) anoxic, acidic, reducing gas (H2 + CO + CO2 + CH4 + N2), reduces the salinity of water. Desalination costs increase with increasing NaCl removal. The cost of reducing water salinity from: (i) 2.65 to 1.55 g·L−1 (over 1–24 h) is $0.002–$0.026 m−3; (ii) 38.6 to 0.55 g·L−1 (over 210 days) is $67.6–$187.2 m−3. Desalination is accompanied by the removal, from the water, of one or more of: nitrate, chloride, fluoride, sulphate, phosphate, As, B, Ba, Ca, Cd, Co, Cu, Fe, Mg, Mn, Na, Ni, P, S, Si, Sr, Zn. The rate of desalination is enhanced by increasing temperatures and increasing HCO3/CO32− concentrations. The rate of desalination decreases with increasing SO42− removal under acidic, or pH neutral, operating conditions. Full article
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Open AccessArticle
Modeling Residential Water Consumption in Amman: The Role of Intermittency, Storage, and Pricing for Piped and Tanker Water
Water 2015, 7(7), 3643-3670; https://doi.org/10.3390/w7073643 - 10 Jul 2015
Cited by 13 | Viewed by 3441
Abstract
Jordan faces an archetypal combination of high water scarcity, with a per capita water availability of around 150 m3 per year significantly below the absolute scarcity threshold of 500 m3, and strong population growth, especially due to the Syrian refugee [...] Read more.
Jordan faces an archetypal combination of high water scarcity, with a per capita water availability of around 150 m3 per year significantly below the absolute scarcity threshold of 500 m3, and strong population growth, especially due to the Syrian refugee crisis. A transition to more sustainable water consumption patterns will likely require Jordan’s water authorities to rely more strongly on water demand management in the future. We conduct a case study of the effects of pricing policies, using an agent-based model of household water consumption in Jordan’s capital Amman, in order to analyze the distribution of burdens imposed by demand-side policies across society. Amman’s households face highly intermittent piped water supply, leading them to supplement it with water from storage tanks and informal private tanker operators. Using a detailed data set of the distribution of supply durations across Amman, our model can derive the demand for additional tanker water. We find that integrating these different supply sources into our model causes demand-side policies to have strongly heterogeneous effects across districts and income groups. This highlights the importance of a disaggregated perspective on water policy impacts in order to identify and potentially mitigate excessive burdens. Full article
(This article belongs to the Special Issue Water Consumption and Water End-uses in Buildings)
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Open AccessArticle
Evaluation of a Modified Monod Model for Predicting Algal Dynamics in Lake Tai
Water 2015, 7(7), 3626-3642; https://doi.org/10.3390/w7073626 - 08 Jul 2015
Cited by 4 | Viewed by 1984
Abstract
Several modified versions of the Monod model have been proposed to simulate algal dynamics in lakes by keeping the parent model’s advantages of simplicity and low data requirement. This study evaluated the performance of a widely-used modified Monod model in predicting algal dynamics [...] Read more.
Several modified versions of the Monod model have been proposed to simulate algal dynamics in lakes by keeping the parent model’s advantages of simplicity and low data requirement. This study evaluated the performance of a widely-used modified Monod model in predicting algal dynamics at various time scales in Lake Tai, a typical shallow lake in east China, using multiple time series. Chlorophyll-a (Chl-a) concentration was used as a surrogate for algal (CyanoHABs: cyanobacterial harmful algal blooms) growth and the independent variables were total nitrogen (TN), total phosphorus (TP), and either water temperature or air temperature. The evaluation indicated that the model parameters could have distinctly different values, depending on whether or not constraints are imposed, time scales, and types of nutrients. The model performance varied in terms of time scales as well as magnitudes and fluctuations of Chl-a and TN or TP concentrations, achieving a relative better performance for the monthly rather than three-day time scale and for the central part rather than bays of the study lake. The model with TP as the independent variable had a better performance than the model with TN as the independent variable, regardless of the time scale used. The temperature-nutrient interactions were important for algal growth when the temporal fluctuations of these two factors were large but the interactions could become minimal otherwise. Full article
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Open AccessCommunication
Multiobjective Optimization of Water Distribution Networks Using Fuzzy Theory and Harmony Search
Water 2015, 7(7), 3613-3625; https://doi.org/10.3390/w7073613 - 08 Jul 2015
Cited by 18 | Viewed by 2188
Abstract
Thus far, various phenomenon-mimicking algorithms, such as genetic algorithm, simulated annealing, tabu search, shuffled frog-leaping, ant colony optimization, harmony search, cross entropy, scatter search, and honey-bee mating, have been proposed to optimally design the water distribution networks with respect to design cost. However, [...] Read more.
Thus far, various phenomenon-mimicking algorithms, such as genetic algorithm, simulated annealing, tabu search, shuffled frog-leaping, ant colony optimization, harmony search, cross entropy, scatter search, and honey-bee mating, have been proposed to optimally design the water distribution networks with respect to design cost. However, flow velocity constraint, which is critical for structural robustness against water hammer or flow circulation against substance sedimentation, was seldom considered in the optimization formulation because of computational complexity. Thus, this study proposes a novel fuzzy-based velocity reliability index, which is to be maximized while the design cost is simultaneously minimized. The velocity reliability index is included in the existing cost optimization formulation and this extended multiobjective formulation is applied to two bench-mark problems. Results show that the model successfully found a Pareto set of multiobjective design solutions in terms of cost minimization and reliability maximization. Full article
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Open AccessArticle
The Challenge of Producing and Marketing Colloidal Silver Water Filters in Nepal
Water 2015, 7(7), 3599-3612; https://doi.org/10.3390/w7073599 - 07 Jul 2015
Cited by 1 | Viewed by 2025
Abstract
Background: Obtaining safe drinking water can be a challenge in Nepal. By training potters and setting up production sites for Colloidal Silver Filters, several non-governmental organizations have tried to provide local people with a low-cost option for household water treatment. Out of 19 [...] Read more.
Background: Obtaining safe drinking water can be a challenge in Nepal. By training potters and setting up production sites for Colloidal Silver Filters, several non-governmental organizations have tried to provide local people with a low-cost option for household water treatment. Out of 19 trained entrepreneurs, only four are currently producing filters. The goal of this evaluation was to find out what conditions lead to the successful continuation of the production and the reasons for failure. Methods: The evaluation of the potters was based on a Qualitative Comparative Analysis and the conditions looked at were: “Production”, “Collaboration”, “Market” and “Potter”. Results: Analysis showed that production problems and insufficient demand led to the termination of ceramic filter production and that both trouble-free production and high demand are necessary for a sustainable business. Full article
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Open AccessArticle
Modeling the Projected Changes of River Flow in Central Vietnam under Different Climate Change Scenarios
Water 2015, 7(7), 3579-3598; https://doi.org/10.3390/w7073579 - 07 Jul 2015
Cited by 11 | Viewed by 2210
Abstract
Recent studies by the United Nations Environment Programme (UNEP) and the Intergovernmental Panel on Climate Change (IPCC) indicate that Vietnam is one of the countries most affected by climate change. The variability of climate in this region, characterized by large fluctuations in precipitation [...] Read more.
Recent studies by the United Nations Environment Programme (UNEP) and the Intergovernmental Panel on Climate Change (IPCC) indicate that Vietnam is one of the countries most affected by climate change. The variability of climate in this region, characterized by large fluctuations in precipitation and temperature, has caused significant changes in surface water resources. This study aims to project the impact of climate change on the seasonal availability of surface water of the Huong River in Central Vietnam in the twenty-first century through hydrologic simulations driven by climate model projections. To calibrate and validate the hydrologic model, the model was forced by the rain gage-based gridded Asian Precipitation–Highly Resolved Observational Data Integration Towards Evaluation of water resources (APHRODITE) V1003R1 Monsoon Asia precipitation data along with observed temperature, humidity, wind speed, and solar radiation data from local weather stations. The simulated discharge was compared to observations for the period from 1951 until present. Three Global Climate Models (GCMs) ECHAM5-OM, HadCM3 and GFDL-CM2.1 integrated into Long Ashton Research Station-Weather Generator (LARS-WG) stochastic weather generator were run for three IPCC–Special Report on Emissions Scenarios (IPCC-SRES) emissions scenarios A1B, A2, and B1 to simulate future climate conditions. The hydrologic model simulated the Huong River discharge for each IPCC-SRES scenario. Simulation results under the three GCMs generally indicate an increase in summer and fall river discharge during the twenty-first century in A2 and B1 scenarios. For A1B scenario, HadCM3 and GFDL-CM2.1 models project a decrease in river discharge from present to the 2051–2080 period and then increase until the 2071–2100 period while ECHAM5-OM model produces opposite projection that discharge will increase until the 2051–2080 period and then decrease for the rest of the century. Water management impacts, such as irrigation or dam regulation, were not considered in this study. However, the results provide local policy makers with quantitative data to consider possible adjustment of future dam capacities for development of flood control policies. Full article
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Open AccessArticle
Impacts of Climate Change on Mean Annual Water Balance for Watersheds in Michigan, USA
Water 2015, 7(7), 3565-3578; https://doi.org/10.3390/w7073565 - 07 Jul 2015
Cited by 4 | Viewed by 1821
Abstract
Evaluation of water balance at the watershed scale is a fundamental step for estimating streamflow in watersheds. Mean annual water balance of 17 watersheds across Michigan were evaluated by comparing observed streamflow with simulated streamflow estimated using Fu’s Equation, which is based on [...] Read more.
Evaluation of water balance at the watershed scale is a fundamental step for estimating streamflow in watersheds. Mean annual water balance of 17 watersheds across Michigan were evaluated by comparing observed streamflow with simulated streamflow estimated using Fu’s Equation, which is based on the Budyko Hypothesis. The Budyko Hypothesis describes mean annual water balance as a function of available water and energy. Impact of long-term climatic controls (e.g., precipitation, potential evapotranspiration (ETP)) on mean annual water balance was also investigated with Fu’s Equation. Results indicated that observed streamflow ranged from 237 to 529 mm per year, with an average of 363 mm per year in the study watersheds during 1967–2011. On average, 40% of long-term precipitation in the study watersheds was converted into surface runoff. The performance of Fu’s Equation in estimating mean annual streamflow resulted in Root Mean Square Error (RMSE) value of 64.1 mm/year. Mean annual streamflow was sensitive to changes in mean annual precipitation, and less sensitive to changes in mean annual ETp in the watersheds. With the increase of baseflow index (BFI), mean annual streamflow was less sensitive to climate change. Overall, different contributions of baseflow to streamflow modified the impact of climate controls on mean annual water balance in the baseflow-dominated watersheds. Full article
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Open AccessArticle
Modeling Flood Hazard Zones at the Sub-District Level with the Rational Model Integrated with GIS and Remote Sensing Approaches
Water 2015, 7(7), 3531-3564; https://doi.org/10.3390/w7073531 - 06 Jul 2015
Cited by 17 | Viewed by 3139
Abstract
Robust risk assessment requires accurate flood intensity area mapping to allow for the identification of populations and elements at risk. However, available flood maps in West Africa lack spatial variability while global datasets have resolutions too coarse to be relevant for local scale [...] Read more.
Robust risk assessment requires accurate flood intensity area mapping to allow for the identification of populations and elements at risk. However, available flood maps in West Africa lack spatial variability while global datasets have resolutions too coarse to be relevant for local scale risk assessment. Consequently, local disaster managers are forced to use traditional methods such as watermarks on buildings and media reports to identify flood hazard areas. In this study, remote sensing and Geographic Information System (GIS) techniques were combined with hydrological and statistical models to delineate the spatial limits of flood hazard zones in selected communities in Ghana, Burkina Faso and Benin. The approach involves estimating peak runoff concentrations at different elevations and then applying statistical methods to develop a Flood Hazard Index (FHI). Results show that about half of the study areas fall into high intensity flood zones. Empirical validation using statistical confusion matrix and the principles of Participatory GIS show that flood hazard areas could be mapped at an accuracy ranging from 77% to 81%. This was supported with local expert knowledge which accurately classified 79% of communities deemed to be highly susceptible to flood hazard. The results will assist disaster managers to reduce the risk to flood disasters at the community level where risk outcomes are first materialized. Full article
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Open AccessArticle
Characterization of the Corrosive Action of Mineral Waters from Thermal Sources: A Case Study at Azores Archipelago, Portugal
Water 2015, 7(7), 3515-3530; https://doi.org/10.3390/w7073515 - 02 Jul 2015
Cited by 2 | Viewed by 2238
Abstract
Waters from natural sources of the São Miguel Island in the Azores archipelago have been investigated regarding their corrosive action on metallic materials. The corrosive and encrusting characteristics of the waters have been established in terms of relevant chemical parameters (namely pH, conductivity, [...] Read more.
Waters from natural sources of the São Miguel Island in the Azores archipelago have been investigated regarding their corrosive action on metallic materials. The corrosive and encrusting characteristics of the waters have been established in terms of relevant chemical parameters (namely pH, conductivity, total dissolved solids (TDS), and concentrations of bicarbonate, calcium, magnesium, chloride, and sulfate ions) and their temperature by using Langelier, Ryznar, Puckorius and Larson–Skold indexes. The validity of this methodology has been tested by measuring the corrosion rates of various metals exposed to various waters using electrochemical methods. The materials of industrial interest under investigation were carbon and galvanized steel, zinc, 304 and 316L grade stainless steels, brass, and Cr–Ni alloys. The greater aggressiveness of these waters was found for the less noble materials, and they experienced high corrosion rates. Full article
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Open AccessArticle
Science-Based IWRM Implementation in a Data-Scarce Central Asian Region: Experiences from a Research and Development Project in the Kharaa River Basin, Mongolia
Water 2015, 7(7), 3486-3514; https://doi.org/10.3390/w7073486 - 01 Jul 2015
Cited by 19 | Viewed by 3173
Abstract
Mongolia is not only a water-scarce but also a data-scarce country with regard to environmental information. At the same time, regional effects of global climate change, major land use changes, a booming mining sector, and growing cities with insufficient and decaying water and [...] Read more.
Mongolia is not only a water-scarce but also a data-scarce country with regard to environmental information. At the same time, regional effects of global climate change, major land use changes, a booming mining sector, and growing cities with insufficient and decaying water and wastewater infrastructures result in an increasingly unsustainable exploitation and contamination of ground and surface water resources putting at risk both aquatic ecosystems and human health. For the mesoscale (≈15,000 km2) model region of the Kharaa River Basin (KRB), we investigated (1) the current state of aquatic ecosystems, water availability and quality; (2) past and expected future trends in these fields and their drivers; (3) water governance structures and their recent reforms; and (4) technical and non-technical interventions as potential components of an integrated water resources management (IWRM). By now, the KRB is recognized as one of the most intensively studied river basins of the country, and considered a model region for science-based water resources management by the Mongolian government which recently adopted the IWRM concept in its National Water Program. Based on the scientific results and practical experiences from a six-year project in the KRB, the potentials and limitations of IWRM implementation under the conditions of data-scarcity are discussed. Full article
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Open AccessArticle
Performance of a Rain Barrel Sharing Network under Climate Change
Water 2015, 7(7), 3466-3485; https://doi.org/10.3390/w7073466 - 01 Jul 2015
Cited by 2 | Viewed by 2007
Abstract
Rain barrels can be technically shared through social practices or mutual agreement between individual households. This study proposes the evaluation system for a rain barrel sharing network (RBSN) considering three performance criteria of reliability, resiliency, and vulnerability, under plausible climate change scenarios. First, [...] Read more.
Rain barrels can be technically shared through social practices or mutual agreement between individual households. This study proposes the evaluation system for a rain barrel sharing network (RBSN) considering three performance criteria of reliability, resiliency, and vulnerability, under plausible climate change scenarios. First, this study shows how the system can be improved in terms of the performance criteria using historical daily rainfall data based on the storage-reliability-yield relationship. This study then examined how the benefits from RBSN are affected by climate change after 100 years. Three climate change scenarios (A1B, A2 and B2) and three global circulation models were used for this purpose. The results showed that the reliability and vulnerability are improved due to sharing and their improvements become larger under climate change conditions. In contrast, the resiliency reduces slightly due to sharing and its reduction is attenuated under climate change conditions. In particular, vulnerability will be reduced significantly under climate change. These results suggest that the sharing of various water resources systems can be an effective climate change adaptation strategy that reduces vulnerability and increases the reliability of the system. Full article
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Open AccessArticle
Assessing the Water Parallel Pricing System against Drought in China: A Study Based on a CGE Model with Multi-Provincial Irrigation Water
Water 2015, 7(7), 3431-3465; https://doi.org/10.3390/w7073431 - 30 Jun 2015
Cited by 12 | Viewed by 2426
Abstract
The reform of water management in China is still in progress, and the pricing of water resources is undertaken in parallel, with a divide between irrigation water and pipe water associated with different users: The supply of irrigation water is regulated by local [...] Read more.
The reform of water management in China is still in progress, and the pricing of water resources is undertaken in parallel, with a divide between irrigation water and pipe water associated with different users: The supply of irrigation water is regulated by local government and that of pipe water is operated by the production sector of pipe water. Based on a literature review and an interview survey of farmers, this study incorporated the water parallel pricing system of China within a computable general equilibrium (CGE) model, where the drought of 2000 is simulated. The 16 provincial irrigation water supplies and their subsidies were also estimated and introduced into this CGE model. The results demonstrated that the effects on the macro-economy were insignificant. However, the effects on agricultural production, particularly on farming production mainly cultivated in northern areas, were significant. Most farming production sectors employed more capital and labor to prevent losses in output from drought. Agricultural labor was shifted from non-farming agricultural production sectors into farming. Both urban and rural households suffered severe losses in welfare and food consumption, even though they benefited from the additional income. Moreover, rural households suffering the worst losses were located in both northern and southern areas. Full article
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Open AccessArticle
Stormwater Field Evaluation and Its Challenges of a Sediment Basin with Skimmer and Baffles at a Highway Construction Site
Water 2015, 7(7), 3407-3430; https://doi.org/10.3390/w7073407 - 30 Jun 2015
Cited by 7 | Viewed by 5045
Abstract
A field-scale data collection plan to monitor and evaluate the performance of a sediment basin design was developed and implemented using portable automatic stormwater samplers, flow modules, a rain gauge, and inflow weirs. The design configuration consisted of a skimmer as the primary [...] Read more.
A field-scale data collection plan to monitor and evaluate the performance of a sediment basin design was developed and implemented using portable automatic stormwater samplers, flow modules, a rain gauge, and inflow weirs. The design configuration consisted of a skimmer as the primary dewatering device, three coir baffles installed inside the basin, polyacrylamide flocculant blocks and ditch checks in the inflow channel. A sediment basin built on a highway construction site in Franklin County, Alabama, U.S. using the aforementioned design configuration was monitored over 16 rainfall events from 15 November 2011 to 6 February 2012. The basin effectively removed sediments during the early stages of construction when the correct type of polyacrylamide flocculant blocks was used, e.g., 97.9% of sediment removal after a rainfall event on 16 November 2011. It is difficult and challenging to dose sediment-laden stormwater inflow with an exact amount of flocculating agent across all runoff producing events since rainfall is a stochastic variable. Based upon results from this study, it is recommended that a minimum volume of 251.9 m3/ha of contributing drainage area be used to sufficiently size a basin, which is still significantly under-designed for a 2-year, 24-h storm event in the southeast. This paper presents challenges and lessons learned regarding sediment basin design, monitoring, and performance that are beneficial to future studies. Full article
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Open AccessArticle
Stochastic Urban Pluvial Flood Hazard Maps Based upon a Spatial-Temporal Rainfall Generator
Water 2015, 7(7), 3396-3406; https://doi.org/10.3390/w7073396 - 30 Jun 2015
Cited by 17 | Viewed by 2483
Abstract
It is a common practice to assign the return period of a given storm event to the urban pluvial flood event that such storm generates. However, this approach may be inappropriate as rainfall events with the same return period can produce different urban [...] Read more.
It is a common practice to assign the return period of a given storm event to the urban pluvial flood event that such storm generates. However, this approach may be inappropriate as rainfall events with the same return period can produce different urban pluvial flooding events, i.e., with different associated flood extent, water levels and return periods. This depends on the characteristics of the rainfall events, such as spatial variability, and on other characteristics of the sewer system and the catchment. To address this, the paper presents an innovative contribution to produce stochastic urban pluvial flood hazard maps. A stochastic rainfall generator for urban-scale applications was employed to generate an ensemble of spatially—and temporally—variable design storms with similar return period. These were used as input to the urban drainage model of a pilot urban catchment (~9 km2) located in London, UK. Stochastic flood hazard maps were generated through a frequency analysis of the flooding generated by the various storm events. The stochastic flood hazard maps obtained show that rainfall spatial-temporal variability is an important factor in the estimation of flood likelihood in urban areas. Moreover, as compared to the flood hazard maps obtained by using a single spatially-uniform storm event, the stochastic maps generated in this study provide a more comprehensive assessment of flood hazard which enables better informed flood risk management decisions. Full article
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Open AccessArticle
Uncertainty Estimation and Evaluation of Shallow Aquifers’ Exploitability: The Case Study of the Adige Valley Aquifer (Italy)
Water 2015, 7(7), 3367-3395; https://doi.org/10.3390/w7073367 - 26 Jun 2015
Cited by 3 | Viewed by 2565
Abstract
Evaluating the sustainability of water uses in shallow aquifers is fundamental for both environmental and socio-economic reasons. Groundwater models are the main tools to sustain informed management plans, yet simulation results are affected by both epistemic and parametric uncertainties. In this study, we [...] Read more.
Evaluating the sustainability of water uses in shallow aquifers is fundamental for both environmental and socio-economic reasons. Groundwater models are the main tools to sustain informed management plans, yet simulation results are affected by both epistemic and parametric uncertainties. In this study, we aim at investigating the effect of model uncertainties on three assessment criteria: depth to water (DTW), recharge/discharge analysis and a newly defined sustainability index S. We consider, as a case study, the shallow aquifer of the Adige Valley, which is highly influenced by surface water dynamics, water withdrawals from pumping wells and a dense network of ditches. Both direct measurements and soft data are used to reduce uncertainty associated to the limited knowledge about the spatial distribution of the hydraulic parameters. Simulation results showed that the aquifer is chiefly influenced by the interaction with the Adige River and that the influence of anthropogenic activities on vulnerability of groundwater resources varies within the study area. This calls for differentiated approaches to water resources management. Uncertainty related to the three assessment criteria is chiefly controlled by uncertainty of the hydrogeological model, although it depends also on the strategy adopted for the management of water resources. Full article
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Open AccessArticle
A Comparative Analysis of Runoff and Soil Loss Characteristics between “Extreme Precipitation Year” and “Normal Precipitation Year” at the Plot Scale: A Case Study in the Loess Plateau in China
Water 2015, 7(7), 3343-3366; https://doi.org/10.3390/w7073343 - 26 Jun 2015
Cited by 8 | Viewed by 2063
Abstract
The highest annual precipitation in Ansai during the past 60 years was observed in 2013. Studying the effects of such extreme annual precipitation on soil erosion can deepen similar research and help predict environmental damage under future extreme rainfall. We selected the runoff [...] Read more.
The highest annual precipitation in Ansai during the past 60 years was observed in 2013. Studying the effects of such extreme annual precipitation on soil erosion can deepen similar research and help predict environmental damage under future extreme rainfall. We selected the runoff plots (area: 4 m × 10 m) of three land-use types: cultivated land (C), wild grassland (W) and switchgrass (S). We monitored corresponding indices in the “extreme year” (2013) and “normal year” (2010–2012). The results were as follows: (1) The rainfall parameters (rainfall amount, EI30, EI60) in the “extreme year” were all higher than those in the “normal year”, especially in July; (2) In July and August, the runoff and soil loss of cultivated land in the “extreme year” increased by 1492.5% and 538.2%, respectively, compared to those in the “normal year”. The silt content of sediment was the highest generally, but the sand content increased relatively in the “extreme year”; (3) The effect of rainfall on soil erosion was the smallest in W; (4) In the “extreme year”, the same EI30 generated more runoff and soil loss than those in the “normal year”. The high antecedent precipitation which would cause high antecedent soil moisture was one of the reasons. The threshold value (100 MJ·mm·ha−1·h−1) of EI30 related to extreme erosion risk was proposed. Full article
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Open AccessArticle
Runoff Response to Climate Warming and Forest Disturbance in a Mid-Mountain Basin
Water 2015, 7(7), 3320-3342; https://doi.org/10.3390/w7073320 - 26 Jun 2015
Cited by 22 | Viewed by 2450
Abstract
A headwater basin in the Sumava Mountains (Czech Republic), the upper Vydra basin, has undergone forest disturbance as a result of repeated windstorms, a bark beetle outbreak, and forest management. This study analyzed the long-term (1961–2010) hydro-climatic changes by using a combination of [...] Read more.
A headwater basin in the Sumava Mountains (Czech Republic), the upper Vydra basin, has undergone forest disturbance as a result of repeated windstorms, a bark beetle outbreak, and forest management. This study analyzed the long-term (1961–2010) hydro-climatic changes by using a combination of statistical analyses, including Mann-Kendall tests, CUSUM analysis, Buishand’s and Petitt’s homogeneity tests, and Kriging. Although the runoff balance over the study period experienced no apparent changes due to climate warming and forest disturbance, significant changes were detected in the share of direct runoff and baseflow, intra-annual variability of the runoff regime, seasonal runoff patterns, and the distribution of peak and low flow events. The seasonal runoff substantially shifted from summers (decreased from 40% to 28%) to springs (increased by 10%). The occurrence of peak flow events has doubled since the 1980s, with a seasonal shift from late spring towards the early spring, while the occurrence of low-flow days decreased by two-thirds. By 1990, these changes were followed by a seasonal shift in runoff from autumn to mid-winter. The changes in hydrological regime in the mid-mountain basin indicate the sensitivity of its hydrological system and the complexity of its feedback with the changing environment. Full article
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Open AccessArticle
Quantification of Fog Water Collection in Three Locations of Tenerife (Canary Islands)
Water 2015, 7(7), 3306-3319; https://doi.org/10.3390/w7073306 - 26 Jun 2015
Cited by 6 | Viewed by 2459
Abstract
We present the results of fog water collection obtained with cylindrical fog gauges at three locations on the northern side of Tenerife island (Spain): La Esperanza (1093 m a.s.l.), Taborno (1015 m a.s.l.), and El Gaitero (1747 m a.s.l.). Concomitant meteorological variables were [...] Read more.
We present the results of fog water collection obtained with cylindrical fog gauges at three locations on the northern side of Tenerife island (Spain): La Esperanza (1093 m a.s.l.), Taborno (1015 m a.s.l.), and El Gaitero (1747 m a.s.l.). Concomitant meteorological variables were also measured. We show that fog precipitation was more frequent than rainfall. However, the volumes and frequency of daily fog water collection varied among the three studied sites, usually not exceeding 10–40 L d−1/m2 of collecting surface. In La Esperanza, fog water harvesting occurred frequently, but was considerably lower than in the other two locations. However, while in Taborno fog water collection episodes were distributed throughout the period, in El Gaitero these were mainly concentrated in two periods, during autumn and winter 2012–2013. The study of the relationships between daily fog water yields and the averages of meteorological variables did not show any clear trend, but it suggested that the greater volumes of collected fog water were logically associated with higher wind speeds and lower solar radiation conditions. Fog water collection in La Esperanza and in Taborno typically occurred within a similar temperature interval (7.5–12.5 °C), while in El Gaitero the phenomenon was associated with a lower temperature range (2.5–10 °C). Full article
(This article belongs to the Special Issue Study, Development and Management of Water in Volcanic Areas)
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Open AccessArticle
Spatio-Temporal Impacts of Biofuel Production and Climate Variability on Water Quantity and Quality in Upper Mississippi River Basin
Water 2015, 7(7), 3283-3305; https://doi.org/10.3390/w7073283 - 26 Jun 2015
Cited by 12 | Viewed by 2481
Abstract
Impact of climate change on the water resources of the United States exposes the vulnerability of feedstock-specific mandated fuel targets to extreme weather conditions that could become more frequent and intensify in the future. Consequently, a sustainable biofuel policy should consider: (a) how [...] Read more.
Impact of climate change on the water resources of the United States exposes the vulnerability of feedstock-specific mandated fuel targets to extreme weather conditions that could become more frequent and intensify in the future. Consequently, a sustainable biofuel policy should consider: (a) how climate change would alter both water supply and demand; and (b) in turn, how related changes in water availability will impact the production of biofuel crops; and (c) the environmental implications of large scale biofuel productions. Understanding the role of biofuels in the water cycle is the key to understanding many of the environmental impacts of biofuels. Therefore, the focus of this study is to model the rarely explored interactions between land use, climate change, water resources and the environment in future biofuel production systems. Results from this study will help explore the impacts of the US biofuel policy and climate change on water and agricultural resources. We used the Soil and Water Assessment Tool (SWAT) to analyze the water quantity and quality consequences of land use and land management related changes in cropping conditions (e.g., more use of marginal lands, greater residue harvest, increased yields), plus management practices due to biofuel crops to meet the Renewable Fuel Standard target on water quality and quantity. Full article
(This article belongs to the Special Issue Water Quality Control and Management)
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Open AccessArticle
The Effects of Operational and Environmental Variables on Efficiency of Danish Water and Wastewater Utilities
Water 2015, 7(7), 3263-3282; https://doi.org/10.3390/w7073263 - 26 Jun 2015
Cited by 16 | Viewed by 1801
Abstract
Efficiency improvement is one of three patterns a public utility should follow in order to get funds for investments realization. The other two are recourse to bank loans or to private equity and tariff increase. Efficiency can be improved, for example, by growth [...] Read more.
Efficiency improvement is one of three patterns a public utility should follow in order to get funds for investments realization. The other two are recourse to bank loans or to private equity and tariff increase. Efficiency can be improved, for example, by growth and vertical integration and may be conditioned by environmental variables, such as customer and output density. Prior studies into the effects of these variables on the efficiency of water utilities do not agree on certain points (e.g., scale and economies of scope) and rarely consider others (e.g., density economies). This article aims to contribute to the literature by analysing the efficiency of water utilities in Denmark, observing the effects of operational and environmental variables. The method is based on two-stage Data Envelopment Analysis (DEA) applied to 101 water utilities. We found that the efficiency of the water sector was not affected by the observed variables, whereas that of wastewater was improved by smaller firm size, vertical integration strategy, and higher population density. Full article
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Open AccessArticle
Rainfall Variability in the Huangfuchuang Watershed and Its Relationship with ENSO
Water 2015, 7(7), 3243-3262; https://doi.org/10.3390/w7073243 - 25 Jun 2015
Cited by 5 | Viewed by 2211
Abstract
The impact of the El Niño-Southern Oscillation (ENSO) phenomenon within the Huangfuchuan watershed, one of the major first-order sub-basins in the middle region of the Yellow River, has not clearly been established. Consequently, the co-varying relationships between rainfall and El Niño/La Niña spanning [...] Read more.
The impact of the El Niño-Southern Oscillation (ENSO) phenomenon within the Huangfuchuan watershed, one of the major first-order sub-basins in the middle region of the Yellow River, has not clearly been established. Consequently, the co-varying relationships between rainfall and El Niño/La Niña spanning the period 1954 to 2010 are investigated. Trends and step changes in annual rainfall are investigated with the Mann-Kendall and the distribution free cumulative sum (CUSUM) tests. Wavelet transforms are employed to perform spectral analysis of temporal variations in rainfall rates within the watershed. Cross wavelet and wavelet coherence transforms are used to study localized co-varying relationships between rainfall and ENSO index. Results from statistical tests indicate that rainfall in the Huangfuchuan watershed is declining, although not significantly. In addition, wavelet coherency and cross wavelet analysis, and comparison of the extracted dominant annual rainfall and 2–7 year ENSO signals demonstrate that ENSO events impact Huangfuchuan rainfall with El Niño corresponding to rainfall decline and La Niña to rainfall increment with a semiannual to annual lag. Full article
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