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Water, Volume 8, Issue 8 (August 2016)

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Open AccessArticle
Evaluation of Soil Water Availability (SWA) Based on Hydrological Modelling in Arid and Semi-Arid Areas: A Case Study in Handan City, China
Water 2016, 8(8), 360; https://doi.org/10.3390/w8080360
Received: 22 May 2016 / Revised: 8 August 2016 / Accepted: 12 August 2016 / Published: 22 August 2016
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Abstract
To evaluate the spatial and temporal soil water availability (SWA) and improve the soil water use efficiency in agriculture, this study established a new index system for SWA evaluation considering the soil storage capacity, the temporal and spatial matching degree between soil water [...] Read more.
To evaluate the spatial and temporal soil water availability (SWA) and improve the soil water use efficiency in agriculture, this study established a new index system for SWA evaluation considering the soil storage capacity, the temporal and spatial matching degree between soil water supply and crop water demand, and the soil water transformation and utilization efficiency. To quantitatively calculate the indexes, a self-developed hydrological model (MODCYCLE) was introduced and applied in Handan City. The results show that MODCYCLE performed well in simulating the soil hydrological processes. A comparison of the observed soil moisture data and the simulated values revealed relative errors below 10% and correlation coefficients all above 0.7. According to the evaluation results, the SWA for different typical years was very unevenly distributed in Handan City. The average SWA in a normal year is 0.71, which is higher than that in dry years at 0.62 and in wet years at 0.65. Regarding different regions, the average SWA was generally much higher in the eastern plain area than that in the western mountainous area. Generally, there is a great potential for improving SWA and further the sustainable development of soil water resource, particularly for dryland farming in similar areas. Full article
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Open AccessArticle
Heavy Metal Contamination in the Surface Layer of Bottom Sediments in a Flow-Through Lake: A Case Study of Lake Symsar in Northern Poland
Water 2016, 8(8), 358; https://doi.org/10.3390/w8080358
Received: 7 July 2016 / Revised: 12 August 2016 / Accepted: 15 August 2016 / Published: 22 August 2016
Cited by 11 | Viewed by 2396 | PDF Full-text (2046 KB) | HTML Full-text | XML Full-text
Abstract
River-lake systems most often behave as hydrographic units, which undergo complex interactions, especially in the contact zone. One such interaction pertains to the role of a river in the dispersal of trace elements carried into and out of a lake. In this study, [...] Read more.
River-lake systems most often behave as hydrographic units, which undergo complex interactions, especially in the contact zone. One such interaction pertains to the role of a river in the dispersal of trace elements carried into and out of a lake. In this study, we aimed to assess the impact of rivers on the accumulation of heavy metals in bottom sediments of natural lakes comprised in postglacial river-lake systems. The results showed that a river flowing through a lake is a key factor responsible for the input of the majority of available fraction of heavy metals (Zn, Mn, Cd and Ni) into the water body and for their accumulation along the flow of river water in the lake. The origin of other accumulated elements were the linear and point sources in catchments. In turn, the Pb content was associated with the location of roads in the direct catchment, while the sediment structure (especially size of fraction and density) could have affected the accumulation of Cr and Zn, which indicated correlations between these metals and fine fraction. Our results suggest that lakes act as filters and contribute to the self-purification of water that flows through them. As a result, the content of most metals in lake sediments showed a decrease by approx. 75% between the upstream (inflow) and downstream (outflow) sections. The increased content of two metals only, such as chromium and cadmium (higher by 2.0 and 2.5 times, respectively, after passing through the lake), was due to the correlation of the metals with fine sand. Both the content and distribution pattern of heavy metals in lake sediments are indicative of the natural response of aquatic ecosystems to environmental stressors, such as pollutant import with river water or climate change. The complex elements creating the water ecosystem of each lake can counteract stress by temporarily removing pollutants such as toxic metals form circulation and depositing them mostly around the delta. Full article
(This article belongs to the Special Issue Lake Restoration and Management in a Climate Change Perspective)
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Open AccessArticle
An Iterated Local Search Algorithm for Multi-Period Water Distribution Network Design Optimization
Water 2016, 8(8), 359; https://doi.org/10.3390/w8080359
Received: 2 June 2016 / Revised: 20 July 2016 / Accepted: 10 August 2016 / Published: 20 August 2016
Cited by 3 | Viewed by 2424 | PDF Full-text (1422 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Water distribution networks consist of different components, such as reservoirs and pipes, and exist to provide users (households, agriculture, industry) with high-quality water at adequate pressure and flow. Water distribution network design optimization aims to find optimal diameters for every pipe, chosen from [...] Read more.
Water distribution networks consist of different components, such as reservoirs and pipes, and exist to provide users (households, agriculture, industry) with high-quality water at adequate pressure and flow. Water distribution network design optimization aims to find optimal diameters for every pipe, chosen from a limited set of commercially available diameters. This combinatorial optimization problem has received a lot of attention over the past forty years. In this paper, the well-studied single-period problem is extended to a multi-period setting in which time varying demand patterns occur. Moreover, an additional constraint—which sets a maximum water velocity—is imposed. A metaheuristic technique called iterated local search is applied to tackle this challenging optimization problem. A full-factorial experiment is conducted to validate the added value of the algorithm components and to configure optimal parameter settings. The algorithm is tested on a broad range of 150 different (freely available) test networks. Full article
(This article belongs to the Special Issue Hydroinformatics and Urban Water Systems)
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Open AccessArticle
Strontium Removal in Seawater by Means of Composite Magnetic Nanoparticles Derived from Industrial Sludge
Water 2016, 8(8), 357; https://doi.org/10.3390/w8080357
Received: 13 June 2016 / Revised: 26 July 2016 / Accepted: 3 August 2016 / Published: 19 August 2016
Cited by 12 | Viewed by 1610 | PDF Full-text (1887 KB) | HTML Full-text | XML Full-text
Abstract
Novel composite magnetic nanoparticles (CuFe2O4) were synthesized from industrial sludge by acid leaching, chemical exchange, and ferrite processes in the laboratory. For the first time, these products were applied to investigate the Sr adsorption kinetics and the related thermodynamics [...] Read more.
Novel composite magnetic nanoparticles (CuFe2O4) were synthesized from industrial sludge by acid leaching, chemical exchange, and ferrite processes in the laboratory. For the first time, these products were applied to investigate the Sr adsorption kinetics and the related thermodynamics in seawater. Rapidly enhanced Sr adsorption was observed when the solution pH changed from 2.61 to 10.25. The maximum adsorption capacity was 23.04 mg·g−1 at 318 K (pH 10.25). Sr adsorption decreased with the increase of the ionic strength from 0.01 to 0.5 mol·L−1 at pH 2.61–pH 10.25, indicating that the outer-sphere mechanism was involved in the Sr adsorption at the pH interval. This reaction is spontaneous and endothermic, as indicated by the negative change in the standard free energy (ΔG° = −5.68, −6.45, and −7.23 kJ·mol−1 at 298, 308, and 318 K, respectively) and positive ΔH° value (2.11 kJ·mol−1). The positive ΔS° (9.38 mol−1·K−1) further confirms that the randomness increased at the solid-solution interface during adsorption. These new results indicate that the composite magnetic nanoparticles can be used for the removal of radiogenic 90Sr nuclide in seawater that was released after the 3/11 earthquake offshore of Japan. Full article
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Open AccessArticle
Impact of Fertilizer N Application on the Grey Water Footprint of Winter Wheat in a NW-European Temperate Climate
Water 2016, 8(8), 356; https://doi.org/10.3390/w8080356
Received: 13 May 2016 / Revised: 3 August 2016 / Accepted: 9 August 2016 / Published: 19 August 2016
Cited by 5 | Viewed by 1662 | PDF Full-text (1381 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Nutrient management is central in water footprint analyses as it exerts strong control over crop yield and potentially contributes to pollution of freshwater, the so-called grey water footprint. In the frame of grey water footprint accounting, two methods are suggested, the constant leaching [...] Read more.
Nutrient management is central in water footprint analyses as it exerts strong control over crop yield and potentially contributes to pollution of freshwater, the so-called grey water footprint. In the frame of grey water footprint accounting, two methods are suggested, the constant leaching fraction approach (10% of applied fertilizer N) and the N surplus approach. We compared both approaches and expected that the N surplus approach gives lower estimates of N leaching (and fertilizer-induced freshwater pollution) when the N surplus is small and higher N leaching estimates when the N surplus is high. We compared N fertilizer application at which the N balance = 0 with the N application at which profit is highest. We further expect pronounced differences in N surplus between farm sites and years, due to yield and soil fertility differences. N response trials were conducted at several locations over three years in Germany. Fertilizer-induced N surplus was calculated from the difference between applied N fertilizer and grain N removal. N fertilizer application at which N balance = 0 (NBal = 0) was lower than economic optimum N application rates (NEcon). N surplus at NEcon was linearly correlated with the additional N applied. Pooled over years and sites the median N surplus was 39 kg N ha−1. Differences between sites rather than between years dominated variation in fertilizer-induced N surplus. Estimated N leaching at NEcon was on average 9% of applied fertilizer N. The product water footprint was on average 180 m3 per ton of grain, but differences between sites were substantial with values varying between 0 and >400 m3 per ton. Yield and protein contents were lower at NBal = 0 compared to NEcon indicating a trade-off between freshwater protection, yield, wheat grain quality and economic optimum N application. Site-specific fertilizer strategies which consider soil type, crop development, annual field water balance, in-season nutrient dynamics and crop rotational effects are key to minimize fertilizer‑induced leaching of N into groundwater. Full article
(This article belongs to the Special Issue Water Footprint Assessment)
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Open AccessArticle
Using Dual Isotopes and a Bayesian Isotope Mixing Model to Evaluate Nitrate Sources of Surface Water in a Drinking Water Source Watershed, East China
Water 2016, 8(8), 355; https://doi.org/10.3390/w8080355
Received: 16 June 2016 / Revised: 1 August 2016 / Accepted: 10 August 2016 / Published: 19 August 2016
Cited by 4 | Viewed by 2289 | PDF Full-text (3406 KB) | HTML Full-text | XML Full-text
Abstract
A high concentration of nitrate (NO3) in surface water threatens aquatic systems and human health. Revealing nitrate characteristics and identifying its sources are fundamental to making effective water management strategies. However, nitrate sources in multi-tributaries and mix land use watersheds [...] Read more.
A high concentration of nitrate (NO3) in surface water threatens aquatic systems and human health. Revealing nitrate characteristics and identifying its sources are fundamental to making effective water management strategies. However, nitrate sources in multi-tributaries and mix land use watersheds remain unclear. In this study, based on 20 surface water sampling sites for more than two years’ monitoring from April 2012 to December 2014, water chemical and dual isotopic approaches (δ15N-NO3 and δ18O-NO3) were integrated for the first time to evaluate nitrate characteristics and sources in the Huashan watershed, Jianghuai hilly region, China. Nitrate-nitrogen concentrations (ranging from 0.02 to 8.57 mg/L) were spatially heterogeneous that were influenced by hydrogeological and land use conditions. Proportional contributions of five potential nitrate sources (i.e., precipitation; manure and sewage, M & S; soil nitrogen, NS; nitrate fertilizer; nitrate derived from ammonia fertilizer and rainfall) were estimated by using a Bayesian isotope mixing model. The results showed that nitrate sources contributions varied significantly among different rainfall conditions and land use types. As for the whole watershed, M & S (manure and sewage) and NS (soil nitrogen) were major nitrate sources in both wet and dry seasons (from 28% to 36% for manure and sewage and from 24% to 27% for soil nitrogen, respectively). Overall, combining a dual isotopes method with a Bayesian isotope mixing model offered a useful and practical way to qualitatively analyze nitrate sources and transformations as well as quantitatively estimate the contributions of potential nitrate sources in drinking water source watersheds, Jianghuai hilly region, eastern China. Full article
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Open AccessArticle
Quantitative Analysis of Groundwater Recharge in an Arid Area, Northwest China
Water 2016, 8(8), 354; https://doi.org/10.3390/w8080354
Received: 19 June 2016 / Revised: 11 August 2016 / Accepted: 12 August 2016 / Published: 19 August 2016
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Abstract
The Mixing Cell Model (MCM) is a useful tool that can be applied to areas with limited hydrogeological data, such as arid areas in northwest China, to transform available groundwater hydrochemical data into quantitative information about an aquifer. In this study, we used [...] Read more.
The Mixing Cell Model (MCM) is a useful tool that can be applied to areas with limited hydrogeological data, such as arid areas in northwest China, to transform available groundwater hydrochemical data into quantitative information about an aquifer. In this study, we used the MCM to quantify water circulation in the study area and to analyze information such as the supply source composition and proportion of the confined aquifer, the main supply aquifer for local drinking water. The MCM simulation results showed that the confined aquifer in the study area is mainly recharged by leakage of water from the upper unconfined aquifer and lateral flow from the eastern and southern tablelands. Unconfined groundwater and lateral flow contributed to 67.69% and 32.31% of the recharge, respectively. The groundwater circulation model of the study area provided quantitative information about water circulation in different parts of the study area, represented by different cells known as A–F. The information from this model provides a scientific basis for the sustainable use and development of water resources in different parts of the study area. Full article
(This article belongs to the Special Issue Tackling Complex Water Problems in China under Changing Environment)
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Open AccessArticle
Estimation of Groundwater Recharge Using Tracers and Numerical Modeling in the North China Plain
Water 2016, 8(8), 353; https://doi.org/10.3390/w8080353
Received: 10 May 2016 / Revised: 2 August 2016 / Accepted: 3 August 2016 / Published: 18 August 2016
Cited by 2 | Viewed by 2157 | PDF Full-text (2893 KB) | HTML Full-text | XML Full-text
Abstract
Water resource shortage has been a serious problem since the 1980s in the North China Plain (NCP), resulting in plenty of environmental problems. Estimating the groundwater recharge rate accurately is vital for managing groundwater effectively. This study applied several methods, including chloride mass-balance, [...] Read more.
Water resource shortage has been a serious problem since the 1980s in the North China Plain (NCP), resulting in plenty of environmental problems. Estimating the groundwater recharge rate accurately is vital for managing groundwater effectively. This study applied several methods, including chloride mass-balance, tracers (bromide and tritium) and numerical modeling (Hydrus-1D), to estimate groundwater recharge at three representative sites of the NCP: Zhengding (ZD), Luancheng (LC) and Hengshui (HS). The chloride concentration of the soil profile in the ZD site showed that the mean recharge was 3.84 mm/year with the residence time of 105 years for soil water transferring through the vadose area of 45.0 m in depth in the preferential flow model mainly. Considering the influence of preferential flow on the soil water movement in the field scale, the traditional methods (e.g., peak method of bromide and tritium tracers based on piston flow described in the literature) could be unsuitable to estimate groundwater recharge in the LC and HS sites, especially in areas with low recharge rates. Therefore, multi-region and mass balance methods were applied in this study. The results of this investigation showed that the mean values of recharge were 124.3 and 18.0 mm/year in the LC and HS sites, respectively, in 2010. Owing to complexity and uncertainty on the surface resulting from the measuring of evapotranspiration, the upper boundary of 1.4 m (under the ground where most of the plant roots did not reach) was chosen for the numerical modeling of Hydrus-1D, and the result showed that the mean recharge was 225 mm/year from 2003 to 2007, consistent with the result of tracers in the previous literature. The result also showed that the positive relation of groundwater recharge and the sum of irrigation and rainfall was presented in the spatial and temporal scale. Additionally, human activities promoted the recharge rate, and recharge rates increased with greater depths in the LC site generally. However, both cases did not appear clearly in the HS site, showing that the low penetrability of soil controlled the recharge rate in this site. Full article
(This article belongs to the Special Issue Tackling Complex Water Problems in China under Changing Environment)
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Open AccessArticle
“Like a Second Home”: Conceptualizing Experiences within the Fox River Watershed through a Framework of Emplacement
Water 2016, 8(8), 352; https://doi.org/10.3390/w8080352
Received: 1 June 2016 / Revised: 9 July 2016 / Accepted: 9 August 2016 / Published: 18 August 2016
Cited by 2 | Viewed by 2051 | PDF Full-text (7511 KB) | HTML Full-text | XML Full-text
Abstract
We propose and implement a new emplacement framework through exploration of the socio-spatial landscape of the Fox River Watershed (FRW) in Northeastern Wisconsin from a particular cultural perspective. Based primarily upon interviews conducted with 16 Hmong people to better understand and learn from [...] Read more.
We propose and implement a new emplacement framework through exploration of the socio-spatial landscape of the Fox River Watershed (FRW) in Northeastern Wisconsin from a particular cultural perspective. Based primarily upon interviews conducted with 16 Hmong people to better understand and learn from the experiences of an important but overlooked FRW stakeholder group, we present our findings through the components of this framework: displacement, misplacement, replacement, and emplacement. Our research reveals that the strength of Hmong culture has persisted through tremendous loss and displacement, to survive and evolve in a new setting. The resettlement of Hmong people in the FRW has afforded relatively widespread access to landscapes that facilitate recreation, social interaction, and food production, enhancing physical and mental health and augmenting household incomes. It has also led to empowerment of women and the emergence of a generation of group members with formal ecological knowledge to add to their existing ethnobiological understanding and cultural foundation of ecological conscience. For such reasons, conservation organizations, policy makers, and departments of natural resources should look to build linking social capital between those in power and marginalized groups such as the Hmong. Full article
(This article belongs to the Special Issue Watershed Protection and Management)
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Open AccessArticle
Engaging Southwestern Tribes in Sustainable Water Resources Topics and Management
Water 2016, 8(8), 350; https://doi.org/10.3390/w8080350
Received: 5 April 2016 / Revised: 12 July 2016 / Accepted: 13 July 2016 / Published: 18 August 2016
Cited by 12 | Viewed by 2614 | PDF Full-text (256 KB) | HTML Full-text | XML Full-text
Abstract
Indigenous peoples in North America have a long history of understanding their societies as having an intimate relationship with their physical environments. Their cultures, traditions, and identities are based on the ecosystems and sacred places that shape their world. Their respect for their [...] Read more.
Indigenous peoples in North America have a long history of understanding their societies as having an intimate relationship with their physical environments. Their cultures, traditions, and identities are based on the ecosystems and sacred places that shape their world. Their respect for their ancestors and ‘Mother Earth’ speaks of unique value and knowledge systems different than the value and knowledge systems of the dominant United States settler society. The value and knowledge systems of each indigenous and non-indigenous community are different but collide when water resources are endangered. One of the challenges that face indigenous people regarding the management of water relates to their opposition to the commodification of water for availability to select individuals. External researchers seeking to work with indigenous peoples on water research or management must learn how to design research or water management projects that respect indigenous cultural contexts, histories of interactions with settler governments and researchers, and the current socio-economic and political situations in which indigenous peoples are embedded. They should pay particular attention to the process of collaborating on water resource topics and management with and among indigenous communities while integrating Western and indigenous sciences in ways that are beneficial to both knowledge systems. The objectives of this paper are to (1) to provide an overview of the context of current indigenous water management issues, especially for the U.S. federally recognized tribes in the Southwestern United States; (2) to synthesize approaches to engage indigenous persons, communities, and governments on water resources topics and management; and (3) to compare the successes of engaging Southwestern tribes in five examples to highlight some significant activities for collaborating with tribes on water resources research and management. In discussing the engagement approaches of these five selected cases, we considered the four “simple rules” of tribal research, which are to ask about ethics, do more listening, follow tribal research protocols, and give back to the community. For the five select cases of collaboration involving Southwestern tribes, the success of external researchers with the tribes involved comprehensive engagement of diverse tribal audience from grassroots level to central tribal government, tribal oversight, on-going dialogue, transparency of data, and reporting back. There is a strong recognition of the importance of engaging tribal participants in water management discussions particularly with pressing impacts of drought, climate change, and mining and defining water rights. Full article
Open AccessArticle
Development of a Component-Based Modeling Framework for Agricultural Water-Resource Management
Water 2016, 8(8), 351; https://doi.org/10.3390/w8080351
Received: 27 April 2016 / Revised: 10 August 2016 / Accepted: 12 August 2016 / Published: 17 August 2016
Cited by 1 | Viewed by 2570 | PDF Full-text (10076 KB) | HTML Full-text | XML Full-text
Abstract
Because hydrologic responses of an agricultural watershed are influenced by many natural and man-made factors including pond/reservoir, management practices, and/or irrigation/drainage, strategies of hydrological modeling for the watershed must be case-dependent and thus carefully designed to effectively reflect their roles as critical hydrologic [...] Read more.
Because hydrologic responses of an agricultural watershed are influenced by many natural and man-made factors including pond/reservoir, management practices, and/or irrigation/drainage, strategies of hydrological modeling for the watershed must be case-dependent and thus carefully designed to effectively reflect their roles as critical hydrologic components in simulation processes. In this study, we propose a component-based modeling framework that accommodates a flexible modeling approach to consider a variety of hydrologic processes and management practices, especially irrigation-reservoir operation and paddy-farming practices, in watershed-scale modeling. The objectives of this study are twofold: to develop a COmponent-based Modeling Framework for Agricultural water-Resources Management (COMFARM) using an object-oriented programming technique, and to evaluate its applicability as a modeling tool to predict the responses of an agricultural watershed characterized with diverse land uses in a case study. COMFARM facilitates quick and easy development of watershed-specific hydrologic models by providing multiple interchangeable simulation routines for each hydrologic component considered. COMFARM is developed with the JAVA programming language, using Eclipse software. The framework developed in this study is applied to simulating hydrologic processes of the Seon-Am irrigation-district watershed consisting primarily of reservoir-irrigated rice paddies in South Korea. The application study clearly demonstrates the applicability of the framework as a convenient method to build models for hydrologic simulation of an agricultural watershed. The newly developed modeling framework, COMFARM is expected to serve as a useful tool in watershed management planning by allowing quick development of case-oriented analysis tools and evaluation of management scenarios customized to a specific watershed. Full article
(This article belongs to the Special Issue Resilient Water Management in Agriculture)
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Open AccessArticle
Controlling Stormwater Quality with Filter Soil—Event and Dry Weather Testing
Water 2016, 8(8), 349; https://doi.org/10.3390/w8080349
Received: 7 June 2016 / Revised: 8 August 2016 / Accepted: 9 August 2016 / Published: 17 August 2016
Cited by 7 | Viewed by 1722 | PDF Full-text (922 KB) | HTML Full-text | XML Full-text
Abstract
The use of filter soil is increasing for control of quality of stormwater runoff prior to infiltration or discharge. This study aimed to gain knowledge about treatment efficacy of filter soils at field scale. Percolate samples from swale-trench systems with filter soil based [...] Read more.
The use of filter soil is increasing for control of quality of stormwater runoff prior to infiltration or discharge. This study aimed to gain knowledge about treatment efficacy of filter soils at field scale. Percolate samples from swale-trench systems with filter soil based on agricultural till with/without limestone were monitored for 15 and 9 rain events respectively. Further, two curb extensions with filter soil based on landfill soil were monitored for 10 and 8 events. Pollutant concentrations in percolate were compared to influent samples from the catchment area. Additionally one of the curb extensions was tested twice by adding high-dose synthetic influent containing runoff pollutants of concern. Despite generally low influent pollutant levels, phosphorus, copper, zinc, lead and some polyaromatic hydrocarbons exceeded guiding criteria for protection of groundwater and freshwater. Concentrations in the percolate were in most cases reduced, but phosphorus increased and despite reduced concentrations copper, lead and benzo(a)pyrene still exceeded guiding criteria. Pollutants from the synthetic influent were efficiently retained, except the pesticide MCPA. Filter soil based on landfill soil tended to perform better than agricultural till. No impact of limestone was observed. Overall the filter soils performed well in retaining pollutants, despite simultaneous processes of mobilization and immobilization. Full article
(This article belongs to the Special Issue Urban Drainage and Urban Stormwater Management)
Open AccessEditorial
Water Resource Variability and Climate Change
Water 2016, 8(8), 348; https://doi.org/10.3390/w8080348
Received: 11 July 2016 / Revised: 10 August 2016 / Accepted: 12 August 2016 / Published: 17 August 2016
Cited by 4 | Viewed by 1657 | PDF Full-text (182 KB) | HTML Full-text | XML Full-text
Abstract
A significant challenge posed by changing climates is how water cycling and surficial and subsurface water availability will be affected at global and regional scales. Such alterations are critical as they often lead to increased vulnerability in ecosystems and human society. Understanding specifically [...] Read more.
A significant challenge posed by changing climates is how water cycling and surficial and subsurface water availability will be affected at global and regional scales. Such alterations are critical as they often lead to increased vulnerability in ecosystems and human society. Understanding specifically how climate change affects water resource variability in different locations is of critical importance to sustainable development in different parts of the world. The papers included in this special issue focus on three broad perspectives associated with water resource variability and climate change. Six papers employ remote sensing, meteorological station-based observational data, and tree-ring records to empirically determine how water resources have been changing over historical time periods. Eight of the contributions focus on modeling approaches to determine how known processes are likely to manifest themselves as climate shifts over time. Two others focus on human perceptions and adaptation strategies in the midst of unstable or unsettled water availability. The findings and methods presented in this collection of papers provide important contributions to the increased study and awareness of climate change on water resources. Full article
(This article belongs to the Special Issue Water Resource Variability and Climate Change) Printed Edition available
Open AccessArticle
Groundwater Governance: The Role of Legal Frameworks at the Local and National Level—Established Practice and Emerging Trends
Water 2016, 8(8), 347; https://doi.org/10.3390/w8080347
Received: 4 May 2016 / Revised: 24 July 2016 / Accepted: 10 August 2016 / Published: 17 August 2016
Cited by 8 | Viewed by 1868 | PDF Full-text (229 KB) | HTML Full-text | XML Full-text
Abstract
Legal frameworks play a crucial role for effective groundwater governance. They flank and support water policy and provide users and the administration with rights and obligations to use, manage, and protect vital resources in order to achieve the overall goal of equitable and [...] Read more.
Legal frameworks play a crucial role for effective groundwater governance. They flank and support water policy and provide users and the administration with rights and obligations to use, manage, and protect vital resources in order to achieve the overall goal of equitable and sustainable water use. This paper discusses key challenges that have to be addressed in water law to manage and protect groundwater effectively. It will provide an overview of established practice in groundwater legislation and discuss recent trends and developments in light of current challenges. It focuses on permit-based systems of administrative water rights but will to a limited extent also deal with customary, community-based, and informal arrangements. It will show that increasingly domestic groundwater legislation is strengthened and ranked on a par with surface water regimes, ideally by dealing with all water resources in an integrated manner. Full article
Open AccessArticle
Water Level Loggers as a Low-Cost Tool for Monitoring of Stormwater Control Measures
Water 2016, 8(8), 346; https://doi.org/10.3390/w8080346
Received: 26 May 2016 / Revised: 5 August 2016 / Accepted: 10 August 2016 / Published: 15 August 2016
Cited by 2 | Viewed by 1707 | PDF Full-text (1736 KB) | HTML Full-text | XML Full-text
Abstract
Stormwater control measures (SCMs) are a key component of watershed health in urbanized areas. SCMs are used to increase infiltration and reduce discharge to streams or storm sewer systems during rain events. Monitoring is important for the evaluation of design and causes of [...] Read more.
Stormwater control measures (SCMs) are a key component of watershed health in urbanized areas. SCMs are used to increase infiltration and reduce discharge to streams or storm sewer systems during rain events. Monitoring is important for the evaluation of design and causes of failure in SCMs. However, the expense of monitoring means it is not always included in stormwater control planning. This study shows how low-cost water level loggers can be used to answer certain questions about SCM performance. Five case studies are presented that use water level loggers to evaluate the overflow of basins, compare a traditional stormpipe trench with an infiltration trench, monitor timing of blue roof storage, show the effects of retrofitting a basin, and provide long term performance data. Water level loggers can be used to answer questions about the timing and location of stormwater overflows, which helps to evaluate the effectiveness of SCMs. More expensive monitoring and modeling can be used as a follow up if needed to more thoroughly assess a site. Nonetheless, low-cost monitoring can be a first step in identifying sites that need improvement or additional monitoring. Full article
(This article belongs to the Special Issue Watershed Protection and Management)
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Open AccessArticle
Hydrogeochemical Characteristics of Groundwater Highly Polluted with Nitrate in an Agricultural Area of Hongseong, Korea
Water 2016, 8(8), 345; https://doi.org/10.3390/w8080345
Received: 27 June 2016 / Revised: 9 August 2016 / Accepted: 11 August 2016 / Published: 15 August 2016
Cited by 11 | Viewed by 1452 | PDF Full-text (3631 KB) | HTML Full-text | XML Full-text
Abstract
The hydrogeochemical characteristics of groundwater, in an area where widespread contamination by nitrate (NO3) was anticipated, were studied using traditional geochemical investigation and multivariate statistical analysis. Widespread NO3 contamination as high as 67.2 mg/L as NO3 [...] Read more.
The hydrogeochemical characteristics of groundwater, in an area where widespread contamination by nitrate ( NO 3 ) was anticipated, were studied using traditional geochemical investigation and multivariate statistical analysis. Widespread NO 3 contamination as high as 67.2 mg/L as NO3–N was observed, and positively correlated with that for chemicals ( Cl , major cations) with surface origin. Principal component analysis (PCA) revealed that three processes affected groundwater chemistry of the area: (1) leaching of pollutants from the ground surface; (2) reduction of NO 3 in areas with low dissolved oxygen (DO); and (3) ingress of low NO 3 deep groundwater. Five sample groups were identified from cluster analysis, and analysis of land use patterns around each group showed that fate and distribution of NO 3 contamination were mainly controlled by surface topography and predominant land use type. The highest NO 3 concentrations were associated with confined livestock feeding operations in hilly terrain areas, where infiltrating water also had high DO. Lower NO 3 concentrations found in the lowland flat areas were thought to be due to either reducing conditions in rice paddies leading to N attenuation or drawing in of deep groundwater by pumping to meet agricultural needs during periods of low rainfall. Full article
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Open AccessArticle
Energy Recovery Using Micro-Hydropower Technology in Water Supply Systems: The Case Study of the City of Fribourg
Water 2016, 8(8), 344; https://doi.org/10.3390/w8080344
Received: 21 June 2016 / Revised: 3 August 2016 / Accepted: 9 August 2016 / Published: 12 August 2016
Cited by 18 | Viewed by 2258 | PDF Full-text (3585 KB) | HTML Full-text | XML Full-text
Abstract
Water supply systems (WWSs) are one of the main manmade water infrastructures presenting potential for micro-hydropower. Within urban networks, local decentralized micro-hydropower plants (MHPs) may be inserted in the regional electricity grid or used for self-consumption at the local grid level. Nevertheless, such [...] Read more.
Water supply systems (WWSs) are one of the main manmade water infrastructures presenting potential for micro-hydropower. Within urban networks, local decentralized micro-hydropower plants (MHPs) may be inserted in the regional electricity grid or used for self-consumption at the local grid level. Nevertheless, such networks are complex and the quantification of the potential for micro-hydropower other than that achieved by replacing pressure reducing valves (PRVs) is difficult. In this work, a methodology to quantify the potential for hydropower based on the excess energy in a network is proposed and applied to a real case. A constructive solution is presented based on the use of a novel micro-turbine for energy conversion, the five blade tubular propeller (5BTP). The location of the MHP within the network is defined with an optimization algorithm that maximizes the net present value after 20 years of operation. These concepts are tested for the WSS in the city of Fribourg, Switzerland. The proposed solution captures 10% of the city’s energy potential and represents an economic interest. The results confirm the location of PRVs as potential sites for energy recovery and stress the need for careful sensitivity analysis of the consumption. Finally, an expedited method is derived to estimate the costs and energy that one 5BTP can produce in a given network. Full article
(This article belongs to the Special Issue Water Systems towards New Future Challenges)
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Open AccessArticle
A Simplified Model for Modular Green Roof Hydrologic Analyses and Design
Water 2016, 8(8), 343; https://doi.org/10.3390/w8080343
Received: 16 May 2016 / Revised: 24 July 2016 / Accepted: 9 August 2016 / Published: 12 August 2016
Cited by 1 | Viewed by 1862 | PDF Full-text (1772 KB) | HTML Full-text | XML Full-text
Abstract
Green roofs can mitigate urban rooftop stormwater runoff. However, the lack of accurate, physically-based performance assessment and design models has hindered their wide application. Most hydrologic or hydraulic models have no direct connection to the physical properties of green roof components such as [...] Read more.
Green roofs can mitigate urban rooftop stormwater runoff. However, the lack of accurate, physically-based performance assessment and design models has hindered their wide application. Most hydrologic or hydraulic models have no direct connection to the physical properties of green roof components such as media type/depth, drainage depth, etc. In an effort to assist design engineers, a simplified yet effective physically-based model was developed and calibrated with pilot data in order to provide green roof hydrologic performance curves to guide design. Precipitations with depths ranging from 0 to 40 cm and durations 30 to 1440 min were simulated for 21 green roof designs to determine the effects of common physical design parameters. Results revealed that effective capacity and transient capacity are the controlling factors for runoff volume reduction for single precipitation events. Including a water storage feature in the design increased cumulative long-term runoff reduction by an average of 23.5%, whereas increasing growth media depth yielded an average 5.3% improvement. Peak reduction and peak delay are governed by media depth and drainage opening size. Study results indicate that LEED criteria should be modified to require specific designer-controlled parameters of storage and media depth for the design storm to ensure desired performance. Full article
(This article belongs to the Special Issue Urban Drainage and Urban Stormwater Management)
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Open AccessArticle
Measuring the Sustainability of Water Plans in Inter-Regional Spanish River Basins
Water 2016, 8(8), 342; https://doi.org/10.3390/w8080342
Received: 30 April 2016 / Revised: 2 August 2016 / Accepted: 5 August 2016 / Published: 11 August 2016
Cited by 2 | Viewed by 1951 | PDF Full-text (924 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
This paper analyses and compares the sustainability of the water plans in the Spanish River basins according to the objectives of the Water Framework Directive. Even though the concept of sustainability has been traditionally associated with the triple bottom line framework, composed of [...] Read more.
This paper analyses and compares the sustainability of the water plans in the Spanish River basins according to the objectives of the Water Framework Directive. Even though the concept of sustainability has been traditionally associated with the triple bottom line framework, composed of economic, environmental, and social dimensions, in this paper sustainability has been enlarged by including governance aspects. Two multicriteria decision analysis approaches are proposed to aggregate the sustainability dimensions. Results show that the environmental dimension plays the most important role in the whole sustainability (40%) of water basins, followed by both economic and social criteria (25%). By contrast, the dimension of governance is the least important for sustainability (11%). A classification of the Spanish basins according to their sustainability indicates that the water agency with the highest sustainability is Western Cantabrian, followed by Eastern Cantabrian and Tagus. By contrast, Minho-Sil, Jucar, and Douro are the least sustainable. Full article
(This article belongs to the collection Water Policy Collection)
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Open AccessArticle
Is Recovery of Large-Bodied Zooplankton after Nutrient Loading Reduction Hampered by Climate Warming? A Long-Term Study of Shallow Hypertrophic Lake Søbygaard, Denmark
Water 2016, 8(8), 341; https://doi.org/10.3390/w8080341
Received: 16 June 2016 / Revised: 26 July 2016 / Accepted: 28 July 2016 / Published: 10 August 2016
Cited by 6 | Viewed by 2062 | PDF Full-text (2789 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Nutrient fluctuations and climate warming can synergistically affect trophic dynamics in lakes, resulting in enhanced symptoms of eutrophication, thereby potentially counteracting restoration measures. We performed a long-term study (23 years) of zooplankton in Danish Lake Søbygaard, which is in recovery after nutrient loading [...] Read more.
Nutrient fluctuations and climate warming can synergistically affect trophic dynamics in lakes, resulting in enhanced symptoms of eutrophication, thereby potentially counteracting restoration measures. We performed a long-term study (23 years) of zooplankton in Danish Lake Søbygaard, which is in recovery after nutrient loading reduction, but now faces the effects of climate warming. We hypothesized that the recovery of large-bodied zooplankton after nutrient loading reduction would be hampered by climate warming through indirect effects on fish size structure. We found a shift in macrozooplankton from initial dominance of Daphnia spp. towards Bosmina spp. as well as a decline in the body size of copepods and an increase in the abundance of nauplii. These changes coincided with the increase in small sized fish as a result of rising water temperature. Despite a reduction in body size, the total biomass of cladocerans increased coinciding with a diminished fish catch per unit effort (CPUE), and likely then an overall reduction in the predation on zooplankton. A cascading effect to phytoplankton was evidenced by enhanced zooplankton:phytoplankton and cladoceran:phytoplankton ratios and a decrease in Chl-a:TP and Chl-a:TN ratios. Our results indicate that climate warming, through changes in the size structure of fish community, has major effects on zooplankton size structure. In Lake Søbygaard, the decline in zooplankton size did not prevent, but modulated, the positive cascading effect on phytoplankton through an expected diminished fish CPUE related to nutrient loading reduction. Full article
(This article belongs to the Special Issue Lake Restoration and Management in a Climate Change Perspective)
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Open AccessArticle
EMD-RBFNN Coupling Prediction Model of Complex Regional Groundwater Depth Series: A Case Study of the Jiansanjiang Administration of Heilongjiang Land Reclamation in China
Water 2016, 8(8), 340; https://doi.org/10.3390/w8080340
Received: 29 June 2016 / Revised: 4 August 2016 / Accepted: 4 August 2016 / Published: 10 August 2016
Cited by 2 | Viewed by 1526 | PDF Full-text (2178 KB) | HTML Full-text | XML Full-text
Abstract
The accurate and reliable prediction of groundwater depth is the basis of the sustainable utilization of regional groundwater resources. However, the complexity of the prediction has been ignored in previous studies of regional groundwater depth system analysis and prediction, making it difficult to [...] Read more.
The accurate and reliable prediction of groundwater depth is the basis of the sustainable utilization of regional groundwater resources. However, the complexity of the prediction has been ignored in previous studies of regional groundwater depth system analysis and prediction, making it difficult to realize the scientific management of groundwater resources. To address this defect, taking complexity diagnosis as the research foundation, this paper proposes a new coupling forecast strategy for evaluating groundwater depth based on empirical mode decomposition (EMD) and a radial basis function neural network (RBFNN). The data used for complexity analysis and modelling are the monthly groundwater depth series monitoring data from 15 long-term monitoring wells from 1997 to 2007, which were collected from the Jiansanjiang Administration of Heilongjiang Agricultural Reclamation in China. The calculation results of the comprehensive complexity index for each groundwater depth series obtained are based on wavelet theory, fractal theory, and the approximate entropy method. The monthly groundwater depth sequence of District 8 of Farm Nongjiang, which has the highest complexity among the five farms in the Jiansanjiang Administration midland, was chosen as the modelling sample series. The groundwater depth series of District 8 of Farm Nongjiang was separated into five intrinsic mode function (IMF) sequences and a remainder sequence by applying the EMD method, which revealed that local groundwater depth has a significant one-year periodic character and an increasing trend. The RBFNN was then used to forecast and stack each EMD separation sequence. The results suggest that the future groundwater depth will remain at approximately 10 m if the past pattern of water use continues, exceeding the ideal depth of groundwater. Thus, local departments should take appropriate countermeasures to conserve groundwater resources effectively. Full article
(This article belongs to the Special Issue Tackling Complex Water Problems in China under Changing Environment)
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Open AccessArticle
Estimated Grass Grazing Removal Rate in a Semiarid Eurasian Steppe Watershed as Influenced by Climate
Water 2016, 8(8), 339; https://doi.org/10.3390/w8080339
Received: 30 June 2016 / Revised: 25 July 2016 / Accepted: 1 August 2016 / Published: 9 August 2016
Cited by 4 | Viewed by 1768 | PDF Full-text (4633 KB) | HTML Full-text | XML Full-text
Abstract
Grazing removal rate of grasses needs to be determined for various climate conditions to address eco-environmental concerns (e.g., desertification) related to steppe grassland degradation. The conventional approach, which requires survey data on animal species and heads as well as grass consumption per individual [...] Read more.
Grazing removal rate of grasses needs to be determined for various climate conditions to address eco-environmental concerns (e.g., desertification) related to steppe grassland degradation. The conventional approach, which requires survey data on animal species and heads as well as grass consumption per individual animal, is too costly and time-consuming to be applied at a watershed scale. The objective of this study was to present a new approach that can be used to estimate grazing removal rate with no requirement of animal-related data. The application of this new approach was demonstrated in a Eurasian semiarid typical-steppe watershed for an analysis period of 2000 to 2010. The results indicate that the removal rate tended to become larger, but its temporal variation tended to become smaller, from the upstream to downstream. Averaged across the watershed, the removal rate ranged from 63.9 to 401.0 g DM m−2 (or 22.4 to 60.9%) during the analysis period. As expected, the removal rate in an atmospherically wetter year was higher than that in an atmospherically drier year. Nevertheless, none of the eleven analysis years had a removal rate higher than the threshold value of 65%, above which the risk of grassland degradation would become much greater. Full article
(This article belongs to the Special Issue Water-Soil-Vegetation Dynamic Interactions in Changing Climate)
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Open AccessArticle
Quantitative Detection and Attribution of Runoff Variations in the Aksu River Basin
Water 2016, 8(8), 338; https://doi.org/10.3390/w8080338
Received: 22 June 2016 / Revised: 2 August 2016 / Accepted: 2 August 2016 / Published: 9 August 2016
Cited by 6 | Viewed by 1451 | PDF Full-text (3397 KB) | HTML Full-text | XML Full-text
Abstract
Since the flow variations of Aksu River are strongly influenced by climate change and human activities which threat the local ecosystem and sustainable development, it is necessary to quantify the impact degree of the driving factors. Therefore, this study aims to quantify the [...] Read more.
Since the flow variations of Aksu River are strongly influenced by climate change and human activities which threat the local ecosystem and sustainable development, it is necessary to quantify the impact degree of the driving factors. Therefore, this study aims to quantify the impacts of climate change and human activities on the variability of runoff in the Aksu River Basin. The Mann-Kendall trend test and accumulative anomaly method were used to detect the break points of the flow difference value (FDV) between the upstream and downstream flume stations. The improved slope change ratio of cumulative quantity (SCRCQ) method and the Soil and Water Assessment Tool (SWAT) model were applied to decouple the contribution of each driving factor to the FDV variations. Furthermore, a Pearson Correlation Analysis was performed to show the relationships among the driving factors and the FDV. The time series prior to the year (1988) of break point was considered as the baseline period. Based on the annual precipitation and the potential evapotranspiration (PET), the relative impacts of precipitation, PET and human activities on FDV variations as determined by the SCRCQ method were 77.35%, −0.98% and 23.63%, respectively. In addition, the SWAT model indicated that climate factors and human activities were responsible for 92.28% and 7.72% of the variability, respectively. Thus, climate change and human activities showed a similar scale of impact on FDV changes. Full article
(This article belongs to the Special Issue Tackling Complex Water Problems in China under Changing Environment)
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Open AccessArticle
Risk Analysis Approach to Rainwater Harvesting Systems
Water 2016, 8(8), 337; https://doi.org/10.3390/w8080337
Received: 30 May 2016 / Revised: 28 July 2016 / Accepted: 29 July 2016 / Published: 8 August 2016
Cited by 2 | Viewed by 2293 | PDF Full-text (316 KB) | HTML Full-text | XML Full-text
Abstract
Urban rainwater reuse preserves water resources and promotes sustainable development in rapidly growing urban areas. The efficiency of a large number of urban water reuse systems, operating under different climate and demand conditions, is evaluated here on the base of a new risk [...] Read more.
Urban rainwater reuse preserves water resources and promotes sustainable development in rapidly growing urban areas. The efficiency of a large number of urban water reuse systems, operating under different climate and demand conditions, is evaluated here on the base of a new risk analysis approach. Results obtained by probability analysis (PA) indicate that maximum efficiency in low demanding scenarios is above 0.5 and a threshold, distinguishing low from high demanding scenarios, indicates that in low demanding scenarios no significant improvement in performance may be attained by increasing the storage capacity of rainwater harvesting tanks. Threshold behaviour is displayed when tank storage capacity is designed to match both the average collected volume and the average reuse volume. The low demand limit cannot be achieved under climate and operating conditions characterized by a disproportion between harvesting and demand volume. Full article
(This article belongs to the Special Issue Urban Drainage and Urban Stormwater Management)
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Open AccessArticle
Water Management Options for Rice Cultivation in a Temperate Area: A Multi-Objective Model to Explore Economic and Water Saving Results
Water 2016, 8(8), 336; https://doi.org/10.3390/w8080336
Received: 30 May 2016 / Revised: 26 July 2016 / Accepted: 1 August 2016 / Published: 8 August 2016
Cited by 8 | Viewed by 1842 | PDF Full-text (2535 KB) | HTML Full-text | XML Full-text
Abstract
Due to the changing climatic and environmental conditions, modifications in agricultural and water policies have been made, and irrigated agriculture has to face the challenge of making a rational and optimal use of the water resource effectively available. This urges rice farming, strongly [...] Read more.
Due to the changing climatic and environmental conditions, modifications in agricultural and water policies have been made, and irrigated agriculture has to face the challenge of making a rational and optimal use of the water resource effectively available. This urges rice farming, strongly and traditionally linked to water, to change the modalities for the use of the resource. If on one hand water saving techniques should be preferred, a different water management in paddy fields may lead to lower yields and higher production costs, with consequent repercussions on farm incomes. The paper recognizes the disagreement between environmental and economic concerns and aims at contributing to the discussion about how to reconcile them by adopting alternative irrigation strategies. From this perspective, a multi-objective linear optimization model is used to explore the trade-offs between conflicting objectives in a rice-growing area in Northern Italy. The model returns the optimal allocation of land subject to three different irrigation strategies, as those previously performed in experimental fields; in addition, a scenario analysis is run to simulate reduced resource availability. Results demonstrate the key role of prioritizing one objective over the other, while introducing cultivars more suitable for dry cultivation enables enlarging the frontier of optimal solutions. Full article
(This article belongs to the collection Water Policy Collection)
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Open AccessArticle
The Influence of the Annual Number of Storms on the Derivation of the Flood Frequency Curve through Event-Based Simulation
Water 2016, 8(8), 335; https://doi.org/10.3390/w8080335
Received: 27 May 2016 / Revised: 26 July 2016 / Accepted: 29 July 2016 / Published: 5 August 2016
Cited by 3 | Viewed by 1642 | PDF Full-text (2904 KB) | HTML Full-text | XML Full-text
Abstract
This study addresses the question of how to select the minimum set of storms that should be simulated each year in order to estimate an accurate flood frequency curve for return periods ranging between 1 and 1000 years. The Manzanares basin (Spain) was [...] Read more.
This study addresses the question of how to select the minimum set of storms that should be simulated each year in order to estimate an accurate flood frequency curve for return periods ranging between 1 and 1000 years. The Manzanares basin (Spain) was used as a study case. A continuous 100,000-year hourly rainfall series was generated using the stochastic spatial–temporal model RanSimV3. Individual storms were extracted from the series by applying the exponential method. For each year, the extracted storms were transformed into hydrographs by applying an hourly time-step semi-distributed event-based rainfall–runoff model, and the maximum peak flow per year was determined to generate the reference flood frequency curve. Then, different flood frequency curves were obtained considering the N storms with maximum rainfall depth per year, with 1 ≤ N ≤ total number of storms. Main results show that: (a) the degree of alignment between the calculated flood frequency curves and the reference flood frequency curve depends on the return period considered, increasing the accuracy for higher return periods; (b) for the analyzed case studies, the flood frequency curve for medium and high return period (50 ≤ return period ≤ 1000 years) can be estimated with a difference lower than 3% (compared to the reference flood frequency curve) by considering the three storms with the maximum total rainfall depth each year; (c) when considering only the greatest storm of the year, for return periods higher than 10 years, the difference for the estimation of the flood frequency curve is lower than 10%; and (d) when considering the three greatest storms each year, for return periods higher than 100 years, the probability of achieving simultaneously a hydrograph with the annual maximum peak flow and the maximum volume is 94%. Full article
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Open AccessArticle
Sediment-Water Exchange, Spatial Variations, and Ecological Risk Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) in the Songhua River, China
Water 2016, 8(8), 334; https://doi.org/10.3390/w8080334
Received: 30 June 2016 / Revised: 29 July 2016 / Accepted: 2 August 2016 / Published: 5 August 2016
Cited by 9 | Viewed by 1772 | PDF Full-text (2861 KB) | HTML Full-text | XML Full-text
Abstract
The sediment-water exchange, spatial variations, and ecological risk of polycyclic aromatic hydrocarbons (PAHs) in the water and sediment of the Songhua River, China, were investigated and assessed in this paper. The fugacity fraction (ff) was used to evaluate the sediment–water exchange [...] Read more.
The sediment-water exchange, spatial variations, and ecological risk of polycyclic aromatic hydrocarbons (PAHs) in the water and sediment of the Songhua River, China, were investigated and assessed in this paper. The fugacity fraction (ff) was used to evaluate the sediment–water exchange of PAHs between the water and sediment. The results suggest that the values of ff decreased with an increasing number of PAH rings. The sediment acts as a secondary emission source for three- and four-ring PAHs, whereas five-ring PAHs were deposited in the sediment from the water. The high ff values of PAHs found in autumn suggest large releases of PAHs after abundant deposition in summer, and the lowest ff values of PAHs occurred in summer. The values were especially low for five- and six-ring PAHs, which exhibited considerable deposition from the water to the sediment. PAHs with low molecular weights showed strong variations, which were potentially caused by their active physical-chemical properties. Additionally, high molecular weight BaP displayed weak variations, increasing the potential risk in the sediment. The simplified qualitative method of Cwater/Csediment is useful for assessing variations in the sediment–water exchange. The relationships between Cwater/Csediment and ff were investigated by determining the Pearson correlation coefficients (R). The results exhibited a significant negative correlation, with R = −1.000 and P = 0.000 for Flu, R = −0.993 and P = 0.007 for Phe, R = −0.998 and P = 0.002 for FlA, and R = −0.971 and P = 0.029 for BaP. The coefficients of variation indicated that five-ring PAHs were more sensitive than three- and four-ring PAHs. Thus, these low-ring PAHs can be easily exchanged between the sediment and the water. Additionally, the ecological risk of PAHs to aquatic organisms in the Songhua River is relatively low. Full article
(This article belongs to the Special Issue Tackling Complex Water Problems in China under Changing Environment)
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Open AccessArticle
Assessment of Water Rights and Irrigation Pricing Reforms in Heihe River Basin in China
Water 2016, 8(8), 333; https://doi.org/10.3390/w8080333
Received: 31 May 2016 / Revised: 19 July 2016 / Accepted: 21 July 2016 / Published: 5 August 2016
Cited by 10 | Viewed by 1431 | PDF Full-text (626 KB) | HTML Full-text | XML Full-text
Abstract
The purpose of this paper is to understand the progress of water rights and irrigation pricing reform in Heihe River Basin (HRB) and their influence on irrigation application. The data came from a village and household level survey conducted in 2009 and 2014 [...] Read more.
The purpose of this paper is to understand the progress of water rights and irrigation pricing reform in Heihe River Basin (HRB) and their influence on irrigation application. The data came from a village and household level survey conducted in 2009 and 2014 in five counties in Zhangye City, HRB. The main component of reforming water rights was issuing water certificates to individual farmers. However, the share of villages that have done so dropped from 70% in 2004 to 28% in 2014. Water pricing reform raised the price of water. For the pricing of surface water, which consists of an area-based fee and a volumetric price, the volumetric price was increased. Econometric results show that amending water rights substantially reduced irrigation application in the early stage of reform (by 2009) but not in the later phase (by 2014). In contrast, higher water prices lowered irrigation applications significantly at both the early and later stages. Further analysis indicates that due to ineffective implementation, high cost of implementation due to large number of farmers, variations in water supply from year to year, and small farm sizes, little benefit is gained from trading. All of these factors played a role in the failure of water rights reforms. Full article
(This article belongs to the Special Issue Tackling Complex Water Problems in China under Changing Environment)
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Open AccessReview
Strategies for Community and Industry Water Management in the Oil Producing Region of North Dakota
Water 2016, 8(8), 331; https://doi.org/10.3390/w8080331
Received: 28 June 2016 / Revised: 26 July 2016 / Accepted: 1 August 2016 / Published: 5 August 2016
Cited by 1 | Viewed by 1430 | PDF Full-text (741 KB) | HTML Full-text | XML Full-text
Abstract
North Dakota’s Bakken region has surged to become an important oil-producing region. One of the key concerns for ensuring sustained growth in this region is the availability of water. This paper will review current water management practices and review alternative policies with special [...] Read more.
North Dakota’s Bakken region has surged to become an important oil-producing region. One of the key concerns for ensuring sustained growth in this region is the availability of water. This paper will review current water management practices and review alternative policies with special attention to the needs of North Dakota’s rural communities. Although the region is semi-arid, there is an abundance of water available in the Missouri River and Lake Sakakawea. Efforts to utilize available water have been impaired by the US Army Corps of Engineers’ reservoir management polices as well as difficulties in constructing infrastructure during boom drilling. North Dakota was fortunate to dedicate oil revenue for water development. In addition, the expansion of regional water systems has been partially funded by sales to drilling operations. These water systems will benefit both industry and local communities. Full article
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Open AccessArticle
Reconstruction of a Storm Map and New Approach in the Definition of Categories of the Extreme Rainfall, Northeastern Sicily
Water 2016, 8(8), 330; https://doi.org/10.3390/w8080330
Received: 16 June 2016 / Revised: 18 July 2016 / Accepted: 21 July 2016 / Published: 5 August 2016
Cited by 1 | Viewed by 1880 | PDF Full-text (5435 KB) | HTML Full-text | XML Full-text
Abstract
After more than 350 mm of rainfall fell in a few hours on 22 November 2011, thousands of landslides and floods were induced in two main zones of Northeastern Sicily. The total rainfall has been reconstructed integrating available rain gauge data with Tropical [...] Read more.
After more than 350 mm of rainfall fell in a few hours on 22 November 2011, thousands of landslides and floods were induced in two main zones of Northeastern Sicily. The total rainfall has been reconstructed integrating available rain gauge data with Tropical Rainfall Measuring Mission (TRMM) satellite data from NASA (National Aeronautics and Space Administration); the landslide distribution in the field has confirmed the pattern of rainfall accumulated on 22 November 2011. Precipitation maxima of 1, 3, 6, 12, and 24 h was recognized as the hazardous events, which marks the evidence of a changing climate, with a shift toward more intense rainfalls in recent times. To investigate the sequence of the annual maxima, the historical time series have been transformed in the Standard normal distribution, from the cumulative probability of the GEV (Generalized Extreme Value) distribution. Following a similar definition of the Standard Precipitation Index (SPI), the transformation of the historical data in the standardized values allows the definition of categories of hourly maxima in term of extreme, severe, moderate, or mild. This transformation allows to eliminate the asymmetry of the time series, so that trends and fluctuations have been highlighted by the progressive accumulation of data (Rescaled Adjust Partial Sum). This statistical approach allows the improvement of the interpretability of the hydrological extreme events, and could also be used in other cases. Full article
(This article belongs to the Special Issue Urban Drainage and Urban Stormwater Management)
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