Open AccessArticle
Integrated Mosquito Management in Experimental Constructed Wetlands: Efficacy of Small-Stature Macrophytes and Fluctuating Hydroperiod
Water 2016, 8(10), 421; doi:10.3390/w8100421 (registering DOI) -
Abstract
The impact of small-stature alkali bulrush (Bolboschoenus maritimus) and two hydroperiod treatments (early season raised water level or ambient water level) on mosquito production and water quality was studied in replicate 0.09 ha free water surface (FWS) treatment wetlands. Following [...] Read more.
The impact of small-stature alkali bulrush (Bolboschoenus maritimus) and two hydroperiod treatments (early season raised water level or ambient water level) on mosquito production and water quality was studied in replicate 0.09 ha free water surface (FWS) treatment wetlands. Following reconfiguration of a 1-ha constructed wetland into a system with six replicate wetlands, bulrush was planted on 0.5-m centers in three 5-m wide bands in each wetland in summer, 2012. Open water and the low density of emergent vegetation effectively limited mosquito production from the bands of B. maritimus in each wetland during summer and autumn of year one. After the autumnal senescence of the bulrush culms, water levels were raised in half of the wetlands during winter and early spring to enhance sinking of dead bulrush biomass to reduce harborage for mosquitoes. Macrophyte coverage continued to increase in both hydroperiod treatments during year two, but non-bulrush species proliferated and eventually overgrew B. maritimus. Immature mosquito abundance in dipper samples from wetlands in the raised water level treatment was greater than from wetlands in the constant water level treatment. During spring of year two, adult mosquito production was associated with volunteer vegetation in the center of the test cells and averaged 6–18 mosquitoes m−2·day−1, approximately twice that of the other treatment. Hydrological regime did not significantly affect water quality performance (removal of nitrogen, phosphorus and chemical oxygen demand) in the wetlands. Alkali bulrush can persist in shallow water (depth < 0.2 m), but did not persist in deeper zones (mean depth > 0.4 m) of the wetlands and after comparatively large stature grasses and cattails colonized the wetlands. Raised planting beds interspersed with zones of deeper water are recommended to facilitate persistence of alkali bulrush and to limit proliferation of superior competitors. Full article
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Open AccessArticle
Evaluation of Dicentrarchus labrax Meats and the Vegetable Quality of Beta vulgaris var. cicla Farmed in Freshwater and Saltwater Aquaponic Systems
Water 2016, 8(10), 423; doi:10.3390/w8100423 (registering DOI) -
Abstract
The purpose of this study is to exploit the euryhaline nature of commercially attractive species for their cultivation in freshwater aquaponic systems. This approach may increase the profitability of aquaponic production in coastal countries where the consumption of marine fish is traditional [...] Read more.
The purpose of this study is to exploit the euryhaline nature of commercially attractive species for their cultivation in freshwater aquaponic systems. This approach may increase the profitability of aquaponic production in coastal countries where the consumption of marine fish is traditional and of commercial relevance. For this purpose, juvenile European sea bass (Dicentrarchus labrax) were reared in an aquaponic freshwater (AFW) system and an aquaponic saltwater (ASW) system (salinity 20 ppt), in combination with chard (Beta vulgaris var. cicla) seedlings, a salt tolerant plant. At the end of the trial, nitrate and phosphate concentration in water significantly increased in the ASW system, suggesting that the ability of B. vulgaris to absorb these substances was limited by salinity. Total reflection X-ray fluorescence spectrometry revealed that the concentration of some oligoelements such as Fe remained lower with respect to the concentration in the freshwater hydroponic solution, in both AFW and ASW. FTIR-Fourier transform infrared spectroscopy on plants showed that growth at high salinity affected their lipid content. In the case of fish, freshwater had no effects on mono- and poly-unsaturated fatty acid profiles, although saturated fatty acids were significantly decreased in D. labrax reared in AFW. Our results demonstrates that it is possible to increase aquaponic profitability by farming D. labrax juveniles in an aquaponic freshwater system together with Beta vulgaris, obtaining good quality products. Full article
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Open AccessArticle
Assessing Climate Change Impacts on Water Resources in the Songhua River Basin
Water 2016, 8(10), 420; doi:10.3390/w8100420 (registering DOI) -
Abstract
The Songhua River Basin (SRB) in Northeast China is one of the areas most sensitive to global climate change because of its high-latitude location. In this study, we conducted a modeling assessment on the potential change of water resources in this region [...] Read more.
The Songhua River Basin (SRB) in Northeast China is one of the areas most sensitive to global climate change because of its high-latitude location. In this study, we conducted a modeling assessment on the potential change of water resources in this region for the coming three decades using the Soil and Water Assessment Tool (SWAT). First, we calibrated and validated the model with historical streamflow records in this basin. Then, we applied the calibrated model for the period from 2020 to 2049 with the projected and downscaled climatic data under two emission scenarios (RCP 4.5 and RCP 8.5). The study results show: (1) The SWAT model performed very well for both the calibration and validation periods in the SRB; (2) The projected temperatures showed a steady, significant increase across the SRB under both scenarios, especially in two sub-basins, the Nenjiang River Basin (NRB) and the Lower SRB (LSRB). With regard to precipitation, both scenarios showed a decreasing trend in the NRB and LSRB but an increasing trend in the Upper Songhua River Basin (USRB); and (3), generally, the hydrologic modeling suggested a decreasing trend of streamflow for 2020–2049. Compared to baseline conditions (1980–2009), the streamflow in the NRB and LSRB would decrease by 20.3%–37.8%, while streamflow in the USRB would experience an increase of 9.68%–17.7%. These findings provide relevant insights into future surface water resources, and such information can be helpful for resource managers and policymakers to develop effective eco-environment management plans and strategies in the face of climate change. Full article
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Open AccessReview
Modes and Approaches of Groundwater Governance: A Survey of Lessons Learned from Selected Cases across the Globe
Water 2016, 8(10), 417; doi:10.3390/w8100417 -
Abstract
The crucial role of groundwater and the centrality of water governance in accommodating growing water demands sustainably are becoming well recognized. We review 10 case studies of groundwater governance—representing diverse global regions and local contexts—from the perspective of four well-established elements: (1) [...] Read more.
The crucial role of groundwater and the centrality of water governance in accommodating growing water demands sustainably are becoming well recognized. We review 10 case studies of groundwater governance—representing diverse global regions and local contexts—from the perspective of four well-established elements: (1) institutional setting; (2) availability and access to information and science; (3) robustness of civil society; and (4) economic and regulatory frameworks. For institutional setting, we find that governing is often a thankless task that paradoxically requires popularity; legislation does not always translate to implementation; conflict resolution is central to governance; and funding is critical for governance. In terms of information access, we see: a need for research for natural systems, social systems, and institutions; trust as an essential element in research; and that urbanized landscapes are critical components of groundwater governance. Looking at civil society robustness, we observe that equity is an essential element for governance; community-based governance requires intention; and leaders can play a powerful role in uniting stakeholders. As for frameworks, the cases suggest that economic incentives sometimes yield unintended results; “indirect” management should be used cautiously; and economic incentives’ effectiveness depends on the system employed. Collectively, the lessons speak to the need for shared governance capacities on the part of governments at multiple levels and civil society actors. Full article
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Open AccessArticle
Drought Assessment in Zacatecas, Mexico
Water 2016, 8(10), 416; doi:10.3390/w8100416 -
Abstract
Water has always been an essential development factor for civilizations, but its erratic distribution in space and time has caused severe socio-economic problems throughout human history due to both scarcity and excess. In Mexico, insufficient rainwater to satisfy crop water requirements is [...] Read more.
Water has always been an essential development factor for civilizations, but its erratic distribution in space and time has caused severe socio-economic problems throughout human history due to both scarcity and excess. In Mexico, insufficient rainwater to satisfy crop water requirements is a recurrent phenomenon. From a meteorological perspective, drought refers to a decay of the rainfall–runoff process below normal values, resulting in lower availability of water resources to satisfy the needs of human activities, particularly those related to agriculture and livestock. This research reports on drought assessment for Zacatecas, Mexico using monthly data from 111 weather stations with temperature and precipitation information from a 33-year period. Drought was characterized by applying the Standardized Precipitation Index and the Reconnaissance Drought Index using 3, 6, and 12 month timescales; both indexes were plotted and mapped for the period 2005 to 2014. The trend indicates rainfall anomalies (from incipient drought to severe drought) in 6 or 7 years, depending of the selected timescale. April was selected to start the drought analysis because it is the month when farmers usually establish rainfed crops in the region. In ten years, Zacatecas has lost 478 million US dollars due to drought. 2005, 2009, and 2011 were the most critical years, with 47%, 39%, and 63% losses in agricultural income. Such values are in agreement with drought severity estimates: 2005 and 2011 were both dry years (drought indexes were less than −1.25 in the whole territory). Full article
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Open AccessArticle
Initial Quantification of Suspended Sediment Loads for Three Alaska North Slope Rivers
Water 2016, 8(10), 419; doi:10.3390/w8100419 -
Abstract
This study provides an initial assessment of suspended sediment transport in three rivers on the Alaska North Slope. From 2011 to 2013, the Anaktuvuk (69°27′51.00′′ N, 151°10′07.00′′ W), Chandler (69°17′0.30′′ N, 151°24′16.14′′ W), and Itkillik (68°51′59.46′′ N, 150°2′24.00′′ W) Rivers were monitored [...] Read more.
This study provides an initial assessment of suspended sediment transport in three rivers on the Alaska North Slope. From 2011 to 2013, the Anaktuvuk (69°27′51.00′′ N, 151°10′07.00′′ W), Chandler (69°17′0.30′′ N, 151°24′16.14′′ W), and Itkillik (68°51′59.46′′ N, 150°2′24.00′′ W) Rivers were monitored for a variety of hydrologic, meteorologic, and sedimentologic characteristics. Watershed response to summer precipitation events was examined for each river. Bed sediment grain-size distribution was calculated using a photographic grid technique. Mean sediment diameters were 27.1 and 41.5 mm (Samples A and B) for the Chandler, 35.8 mm for the Anaktuvuk, and 65.0 mm for the Itkillik. Suspended sediment rating curves were developed for each river. Suspended sediment discharge was analyzed. In 2011 and 2013, most of the total annual suspended sediment transport occurred during spring melt and widespread rainfall events, respectively. The results show that each river reacts differently to environmental inputs such as rain and basin characteristics. Full article
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Open AccessArticle
Modeling Flow Pattern and Evolution of Meandering Channels with a Nonlinear Model
Water 2016, 8(10), 418; doi:10.3390/w8100418 -
Abstract
Meander dynamics has been the focus of river engineering for decades; however, it remains a challenge for researchers to precisely replicate natural evolution processes of meandering channels with numerical models due to the high nonlinearity of the governing equations. The present study [...] Read more.
Meander dynamics has been the focus of river engineering for decades; however, it remains a challenge for researchers to precisely replicate natural evolution processes of meandering channels with numerical models due to the high nonlinearity of the governing equations. The present study puts forward a nonlinear model to simulate the flow pattern and evolution of meandering channels. The proposed meander model adopts the nonlinear hydrodynamic submodel developed by Blanckaert and de Vriend, which accounts for the nonlinear interactions between secondary flow and main flow and therefore has no curvature restriction. With the computational flow field, the evolution process of the channel centerline is simulated using the Bank Erosion and Retreat Model (BERM) developed by Chen and Duan. Verification against two laboratory flume experiments indicates the proposed meander model yields satisfactory agreement with the measured data. For comparison, the same experimental cases are also simulated with the linear version of the hydrodynamic submodel. Calculated results show that the flow pattern and meander evolution process predicted by the nonlinear and the linear models are similar for mildly curved channels, whereas they exhibit different characteristics when channel sinuosity becomes relatively high. It is indicated that the nonlinear interactions between main flow and secondary flow prevent the growth of the secondary flow and induce a more uniform transverse velocity profile in high-sinuosity channels, which slows down the evolution process of meandering channels. Full article
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Open AccessArticle
Water Budget Analysis in Arid Regions, Application to the United Arab Emirates
Water 2016, 8(9), 415; doi:10.3390/w8090415 -
Abstract
Population growth and economic development have impacted the capacity of water resources to meet demands in a number of arid countries. This study focuses on the United Arab Emirates (UAE) where low rainfall, high rate of growth and agricultural development are resulting [...] Read more.
Population growth and economic development have impacted the capacity of water resources to meet demands in a number of arid countries. This study focuses on the United Arab Emirates (UAE) where low rainfall, high rate of growth and agricultural development are resulting in a dramatic depletion of groundwater resources and an increased dependence on desalination. A water budget for the region was developed. It represents the variations in groundwater storage as a balance of total precipitation, desalinated water and evapotranspiration. The components of the water budget are obtained from ground observations, documented information, models and remote sensing data, using Gravity Recovery and Climate Experiment (GRACE) satellites to estimate changes in groundwater storage and Tropical Rainfall Measuring Mission (TRMM) satellites and Global Land Data Assimilation System (GLDAS) data to obtain precipitation and soil moisture respectively. Results show a negative trend of 0.5 cm/year in groundwater levels corresponding to an average decrease of 0.86 km3/year during the study period (2003 to 2012). This negative trend indicates that the aquifers are not being recharged fast enough to compensate for human withdrawals. Most of the precipitation was found to be lost through evapotranspiration. A discussion of the current water budget components is presented and propositions are made for a sustainable use of water resources in the UAE, including a more efficient use of recycled water. This analysis is applicable to other Gulf countries and it can help to determine the optimal allocation of water resources to optimize agricultural productivity. Full article
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Open AccessArticle
Contributions of Climate Variability and Human Activities to Runoff Changes in the Upper Catchment of the Red River Basin, China
Water 2016, 8(9), 414; doi:10.3390/w8090414 -
Abstract
Quantifying the effects of climate variability and human activities on runoff changes will contribute to regional water resource planning and management. This study aims to separate the effects of climate variability and human activities on runoff changes in the upper catchment of [...] Read more.
Quantifying the effects of climate variability and human activities on runoff changes will contribute to regional water resource planning and management. This study aims to separate the effects of climate variability and human activities on runoff changes in the upper catchment of the Red River Basin in China. The Mann–Kendall test and Pettitt’s test methods were applied to identify the trends and change points of the hydro-meteorological variables. The hydrological sensitivity, climate elasticity and hydrological simulation methods were adopted to estimate the contributions of climate variability and human activities to runoff changes. Results showed that annual runoff significantly decreased by 1.57 mm/year during the period of 1961–2012. A change point in annual runoff coefficient occurred in 2002. Accordingly, the annual runoff series were divided into the baseline period (1961–2002) and the impacted period (2003–2012). Mean annual runoff of the impacted period decreased by 29.13% compared with the baseline period. Similar estimates of the contributions of climate variability and human activities were obtained by the three different methods. Climate variability was estimated to be responsible for 69%–71% of the reduction in annual runoff, and human activities accounted for 29%–31%. Climate variability was the main driving factor for runoff decrease in the catchment. Full article
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Open AccessArticle
The Usefulness of the Lombard Method for Analyzing the Hydrological Impacts of Dams: The Case of the Manouane River Diversion Dam, Quebec, Canada
Water 2016, 8(9), 410; doi:10.3390/w8090410 -
Abstract
The goal of this study is to demonstrate the usefulness of the Lombard method for analyzing dam-induced hydrologic impacts. The method was used to accurately detect the effects of the construction of a diversion dam in 2003 on annual and seasonal maximum [...] Read more.
The goal of this study is to demonstrate the usefulness of the Lombard method for analyzing dam-induced hydrologic impacts. The method was used to accurately detect the effects of the construction of a diversion dam in 2003 on annual and seasonal maximum and minimum daily flows in the Manouane River, Quebec, Canada, measured from 1980 to 2014. The Lombard method yields results that are nearly identical to results obtained using the monitoring (Kruskal-Wallis test) and long-term trend (Mann-Kendall test) methods. The Lombard method revealed a shift in mean values of annual and seasonal minimum daily flows in 2003, the year the dam was built. This shift is sharp for all four seasons. The dam induced a significant decrease in minimum daily flows in all four seasons. As far as maximum daily flows are concerned, unlike the monitoring method, the Lombard method detected a significant decrease only in the mean values of annual and spring maximum daily flows. This decrease occurred two years prior to the construction of the diversion dam. Instead, this decrease is interpreted to be the result of a significant decrease in spring precipitation after 1997. These hydrological changes are different from those induced by other types of dams in Quebec. Full article
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Open AccessArticle
Improving Water Sustainability and Food Security through Increased Crop Water Productivity in Malawi
Water 2016, 8(9), 411; doi:10.3390/w8090411 -
Abstract
Agriculture accounts for most of the renewable freshwater resource withdrawals in Malawi, yet food insecurity and water scarcity remain as major challenges. Despite Malawi’s vast water resources, climate change, coupled with increasing population and urbanisation are contributing to increasing water scarcity. Improving [...] Read more.
Agriculture accounts for most of the renewable freshwater resource withdrawals in Malawi, yet food insecurity and water scarcity remain as major challenges. Despite Malawi’s vast water resources, climate change, coupled with increasing population and urbanisation are contributing to increasing water scarcity. Improving crop water productivity has been identified as a possible solution to water and food insecurity, by producing more food with less water, that is, to produce “more crop per drop”. This study evaluated crop water productivity from 2000 to 2013 by assessing crop evapotranspiration, crop production and agricultural gross domestic product (Ag GDP) contribution for Malawi. Improvements in crop water productivity were evidenced through improved crop production and productivity. These improvements were supported by increased irrigated area, along with improved agronomic practices. Crop water productivity increased by 33% overall from 2000 to 2013, resulting in an increase in maize production from 1.2 million metric tons to 3.6 million metric tons, translating to an average food surplus of 1.1 million metric tons. These developments have contributed to sustainable improved food and nutrition security in Malawi, which also avails more water for ecosystem functions and other competing economic sectors. Full article
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Open AccessArticle
A New Method for Evaluating Riverside Well Locations Based on Allowable Withdrawal
Water 2016, 8(9), 412; doi:10.3390/w8090412 -
Abstract
This study aims to derive the optimal solution for well locations based on the allowable withdrawal. To demonstrate the proposed technique, a numerical model of a typical well field at the Qinbei Power Plant was constructed and 20 possible drawdown scenarios were [...] Read more.
This study aims to derive the optimal solution for well locations based on the allowable withdrawal. To demonstrate the proposed technique, a numerical model of a typical well field at the Qinbei Power Plant was constructed and 20 possible drawdown scenarios were simulated for each of three different arrangements of pumping wells. The concept of the Unit Increased Drawdown Value (UIDV) was used as a basis to select the location of pumping wells, where the UIDV is defined as the increase in drawdown associated with the addition of a unit of extraction. Results showed that for modeled well fields with the same number of wells and rates of exploitation, drawdown will reach the maximum and minimum when the well field is located in the recharge zone and discharge zone, respectively, because of the specific relationships between groundwater and surface water. This paper considered a pumping program with maximum exploitation and minimum costs corresponding to allowable withdrawals of 2.44 m3/s and 1.07 m3/s, respectively, and the relationship between groundwater and surface water was elucidated. The study results provide a theoretical basis for the layout of wells. The solution takes economic factors into consideration and describes the best solution for well locations to meet drawdown limitations during pumping applications. Full article
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Open AccessArticle
Discharge Fee Policy Analysis: A Computable General Equilibrium (CGE) Model of Water Resources and Water Environments
Water 2016, 8(9), 413; doi:10.3390/w8090413 -
Abstract
To alleviate increasingly serious water pollution and shortages in developing countries, various kinds of policies have been implemented by local governments. It is vital to quantify and evaluate the performance and potential economic impacts of these policies. This study develops a Computable [...] Read more.
To alleviate increasingly serious water pollution and shortages in developing countries, various kinds of policies have been implemented by local governments. It is vital to quantify and evaluate the performance and potential economic impacts of these policies. This study develops a Computable General Equilibrium (CGE) model to simulate the regional economic and environmental effects of discharge fees. Firstly, water resources and water environment factors are separated from the input and output sources of the National Economic Production Department. Secondly, an extended Social Accounting Matrix (SAM) of Jiangsu province is developed to simulate various scenarios. By changing values of the discharge fees (increased by 50%, 100% and 150%), three scenarios are simulated to examine their influence on the overall economy and each industry. The simulation results show that an increased fee will have a negative impact on Gross Domestic Product (GDP). However, waste water may be effectively controlled. Also, this study demonstrates that along with the economic costs, the increase of the discharge fee will lead to the upgrading of industrial structures from a situation of heavy pollution to one of light pollution which is beneficial to the sustainable development of the economy and the protection of the environment. Full article
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Open AccessArticle
Multiple Changes in the Hydrologic Regime of the Yangtze River and the Possible Impact of Reservoirs
Water 2016, 8(9), 408; doi:10.3390/w8090408 (registering DOI) -
Abstract
This paper investigates hydrologic changes in the Yangtze River using long-term daily stream flow records (1955–2013) collected from four flow gauging stations located from the upper to the lower reaches of the river. The hydrologic regime is quantified using the Indicators of [...] Read more.
This paper investigates hydrologic changes in the Yangtze River using long-term daily stream flow records (1955–2013) collected from four flow gauging stations located from the upper to the lower reaches of the river. The hydrologic regime is quantified using the Indicators of Hydrologic Alteration, which statistically characterize hydrologic variation within each year. Scanning t-test is applied to analyze multiple changes in the hydrologic regime at different time scales. Then, coherency analysis is applied to identify common changes among different hydrologic indicators and across different reaches of the Yangtze River. The results point to various change patterns in the five components of hydrologic regime, including the magnitude of monthly water conditions, magnitude and duration of annual extreme water conditions, timing of annual extreme water conditions, frequency and duration of high and low pulses, and rate and frequency of water condition changes. The 32 hydrologic indicators feature multiple temporal-scale changes. Spatial variations can be observed in the hydrologic changes of the upper, middle, and lower reaches of the river. Common changes in different reaches consist of hydrologic indicators including the monthly flow in October and the low-flow indicators. The monthly flow in October is dominated by decreasing trends, while the monthly flows between January and March, the annual minimum 1/3/7/30/90-day flows, and the base flow index are characterized by increasing trends. Low pulse duration and total days of low pulses feature downward trends. The coherency analysis reveals significant relationships between the monthly flow in October and the low-flow indicators, indicating that reservoir regulation is an important factor behind the hydrologic changes. Full article
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Open AccessArticle
The Effect of Artificial Recharge on Hydrochemistry: A Comparison of Two Fluvial Gravel Pit Lakes with Different Post-Excavation Uses in The Netherlands
Water 2016, 8(9), 409; doi:10.3390/w8090409 (registering DOI) -
Abstract
Gravel pit lakes form when gravel deposits are excavated below the water table. We studied two fluvial gravel pit lakes called De Lange Vlieter (DLV Lake) and the Boschmolen Plas (BP Lake), in the Meuse River valley (The Netherlands). Water from the [...] Read more.
Gravel pit lakes form when gravel deposits are excavated below the water table. We studied two fluvial gravel pit lakes called De Lange Vlieter (DLV Lake) and the Boschmolen Plas (BP Lake), in the Meuse River valley (The Netherlands). Water from the Meuse River is pumped only into the DLV Lake that is used for drinking water production. The mean values, the linear trends and seasonal patterns of time series data (2003–2014), of temperature, pH, nitrate, phosphate and sulphate were compared using one-way tests of variance and tests of differences. The effects of river water infiltration on DLV Lake are (1) a change in lake water temperature; (2) an increase in nitrate concentration (3) an increase in phosphate concentration and (4) a decrease in sulphate concentration. The effects of the air blowers in DLV Lake are (1) mixing of lake water; (2) decreasing pH in spring and summer (3) water oxygenation. Linear regression analysis shows an initially increasing nitrate concentration in DLV Lake that can be explained by the input of nitrate rich Meuse river water. Instead decreasing nitrate and phosphate concentrations in BP Lake and Meuse River reflect a diminished use of fertilizers. The gravel pit lake water temperature does not reflect climatic changes but the use of DLV Lake for artificial recharge has an impact on the seasonal and long-term trends in hydrochemistry. This poses a challenge to lake managers to find the right balance between reduction of eutrophication and accumulation of nutrients and sulphate. Full article
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Open AccessArticle
Strategic Framework for Sustainable Management of Drainage Systems in Semi-Arid Cities: An Iraqi Case Study
Water 2016, 8(9), 406; doi:10.3390/w8090406 -
Abstract
For the purpose of this paper, Erbil city, located in the northern part of Iraq, has been chosen as a representative case study for a large number of cities, particularly in semi-arid areas, lacking sustainable drainage systems (SuDS). The study assesses (a) [...] Read more.
For the purpose of this paper, Erbil city, located in the northern part of Iraq, has been chosen as a representative case study for a large number of cities, particularly in semi-arid areas, lacking sustainable drainage systems (SuDS). The study assesses (a) the role of SuDS as a measure in areas with a water shortage; (b) water scarcity in decision-making processes; (c) the lack of legislation to implement SuDS; (d) the adverse effects of climate change on the urban drainage system; and (e) the effects of an increased population on SuDS implementation. An integrated methodology that incorporates a self-administrated questionnaire, workshops, face-to-face communication and interviews, as well as electronic media interactions, were used to achieve the objectives. A generic platform that consists of thirteen pillars, supporting the short to long-term national policies and strategies towards a sustainable urban drainage system, has been developed. Results showed that environmental laws need to be introduced. Findings also indicate that a growing population, which is partly due to an increase of internally displaced people, is a major challenge to an early application of SuDS, due to a rise in land demand and a lack of financial resources. Full article
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Open AccessArticle
Integrating Artificial Neural Networks into the VIC Model for Rainfall-Runoff Modeling
Water 2016, 8(9), 407; doi:10.3390/w8090407 -
Abstract
A hybrid rainfall-runoff model was developed in this study by integrating the variable infiltration capacity (VIC) model with artificial neural networks (ANNs). In the proposed model, the prediction interval of the ANN replaces separate, individual simulation (i.e., single simulation). The spatial heterogeneity [...] Read more.
A hybrid rainfall-runoff model was developed in this study by integrating the variable infiltration capacity (VIC) model with artificial neural networks (ANNs). In the proposed model, the prediction interval of the ANN replaces separate, individual simulation (i.e., single simulation). The spatial heterogeneity of horizontal resolution, subgrid-scale features and their influence on the streamflow can be assessed according to the VIC model. In the routing module, instead of a simple linear superposition of the streamflow generated from each subbasin, ANNs facilitate nonlinear mappings of the streamflow produced from each subbasin into the total streamflow at the basin outlet. A total of three subbasins were delineated and calibrated independently via the VIC model; daily runoff errors were simulated for each subbasin, then corrected by an ANN bias-correction model. The initial streamflow and corrected runoff from the simulation for individual subbasins serve as inputs to the ANN routing model. The feasibility of this proposed method was confirmed according to the performance of its application to a case study on rainfall-runoff prediction in the Jinshajiang River Basin, the headwater area of the Yangtze River. Full article
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Open AccessArticle
The Political Ecology of Chinese Large Dams in Cambodia: Implications, Challenges and Lessons Learnt from the Kamchay Dam
Water 2016, 8(9), 405; doi:10.3390/w8090405 -
Abstract
Given the opportunities offered by foreign investment in energy infrastructure mostly by Chinese firms, the Government of Cambodia is giving high priority to developing hydropower resources for reducing energy poverty and powering economic growth. Using a “Political ecology of the Asian drivers” [...] Read more.
Given the opportunities offered by foreign investment in energy infrastructure mostly by Chinese firms, the Government of Cambodia is giving high priority to developing hydropower resources for reducing energy poverty and powering economic growth. Using a “Political ecology of the Asian drivers” framework, this paper assesses China’s involvement in the development of large dams’ in Cambodia and its impacts on the access of natural resources such as water and energy by dam builders, local communities and the government. This analysis is based on 61 interviews and 10 focus group discussions with affected communities, institutional actors, Chinese dam builders and financiers in relation to the first large Chinese dam built in Cambodia: the Kamchay dam. Based on the results of the analysis this paper makes recommendations on how to improve the planning, implementation and governance of future large dams in Cambodia. Full article
Open AccessArticle
Shedding Light on Increasing Trends of Phosphorus Concentration in Upper Austrian Rivers
Water 2016, 8(9), 404; doi:10.3390/w8090404 -
Abstract
Phosphorus (P) impairment of surface waters still represents a major concern worldwide, despite decades of awareness and implementation of remedial measures. In view of this situation, it is all the more necessary to provide decision makers with reliable modelling tools, which can [...] Read more.
Phosphorus (P) impairment of surface waters still represents a major concern worldwide, despite decades of awareness and implementation of remedial measures. In view of this situation, it is all the more necessary to provide decision makers with reliable modelling tools, which can correctly estimate the effect of alternative management strategies. This work tests the performance of the semi-empirical model MONERIS (Modelling of Nutrient Emissions in River Systems) in depicting and quantifying trends of instream total phosphorus (TP) concentration in three catchments located in Upper Austria, a region affected by high agricultural nutrients emissions. The model correctly depicts both the existence of increasing trends (4–µg TP L1year1) and the lack thereof (<0.1 µg TP L1year1) in different sub-catchments within the period 2001–2014, although it systematically underestimates the trends magnitude. Furthermore, MONERIS together with an optimized data management system has allowed identifying the probable cause of such trends. The results suggest that, despite considerable improvements achieved through enhanced P removal from wastewater and through the implementation of an agri-environmental programme, changes in land use and in cultivated crop types have led to an offsetting increase of erosion-driven emissions. This methodology offers high potential to predict the effect of different management scenarios, but further model fine-tuning concerning erosion and retention processes is required to improve the model accuracy. Full article
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Open AccessArticle
Evolutionary and Holistic Assessment of Green-Grey Infrastructure for CSO Reduction
Water 2016, 8(9), 402; doi:10.3390/w8090402 -
Abstract
Recent research suggests future alterations in rainfall patterns due to climate variability, affecting public safety and health in urban areas. Urban growth, one of the main drivers of change in the current century, will also affect these conditions. Traditional drainage approaches using [...] Read more.
Recent research suggests future alterations in rainfall patterns due to climate variability, affecting public safety and health in urban areas. Urban growth, one of the main drivers of change in the current century, will also affect these conditions. Traditional drainage approaches using grey infrastructure offer low adaptation to an uncertain future. New methodologies of stormwater management focus on decentralized approaches in a long-term planning framework, including the use of Green Infrastructure (GI). This work presents a novel methodology to select, evaluate, and place different green-grey practices (or measures) for retrofitting urban drainage systems. The methodology uses a hydrodynamic model and multi-objective optimization to design solutions at a watershed level. The method proposed in this study was applied in a highly urbanized watershed to evaluate the effect of these measures on Combined Sewer Overflows (CSO) quantity. This approach produced promising results and may become a useful tool for planning and decision making of drainage systems. Full article
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