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Water, Volume 10, Issue 10 (October 2018)

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Cover Story (view full-size image) Soil erosion induced by heavy rainfall has a strong impact on landscape changes. This is documented [...] Read more.
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Open AccessArticle A Multi-Criteria Assessment of Water Supply in Ugandan Refugee Settlements
Water 2018, 10(10), 1493; https://doi.org/10.3390/w10101493
Received: 21 September 2018 / Revised: 12 October 2018 / Accepted: 15 October 2018 / Published: 22 October 2018
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Abstract
Water supply challenges in emergency situations have increased in recent years and there is a need for analyses targeting economic and environmental sustainability. Our study investigated the end-user water demand, the capital and operational costs, the carbon footprint, the freshwater availability and the
[...] Read more.
Water supply challenges in emergency situations have increased in recent years and there is a need for analyses targeting economic and environmental sustainability. Our study investigated the end-user water demand, the capital and operational costs, the carbon footprint, the freshwater availability and the risks surrounding water quality for several groundwater supply alternatives in Ugandan refugee settlements. We compared hand pumps, motorised pumps (solar, diesel and hybrid) and water trucking. The end-users’ survey highlighted the significant variability of water access. The economic evaluation showed that the breakeven year for solar and diesel pumps was greatly affected by the length of the water distribution systems (e.g., pipes, storage tanks), the chosen timeframe and the daily working hours of the diesel engine. When excluding capital investment, most alternatives were economically viable at the existing water fee (0.8 USD/m3), and solar driven pumps were down to 0.09 USD/m3. Finally, the combustion of diesel caused the highest CO2-eq emissions per m3. Water trucking is the worst option in both the economic and environmental analysis at 7–8 USD/m3 and >1 kg CO2-eq/m3. The methodology and the results of this paper will support decision-makers to build and finance sustainable water provision solutions in refugee settlements. Full article
(This article belongs to the Section Water Resources Management and Governance)
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Open AccessArticle Numerical Analysis of Sensitivity of Structure of the Stratification in Lake Biwa, Japan by Changing Meteorological Elements
Water 2018, 10(10), 1492; https://doi.org/10.3390/w10101492
Received: 7 August 2018 / Revised: 16 October 2018 / Accepted: 18 October 2018 / Published: 22 October 2018
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Abstract
Climatic factors such as air temperature and wind speed can affect the structure of stratification in Lake Biwa. In general, the rise in air temperature and the decrease in wind speed weaken the vertical mixing and strengthen the structure of the stratification, which
[...] Read more.
Climatic factors such as air temperature and wind speed can affect the structure of stratification in Lake Biwa. In general, the rise in air temperature and the decrease in wind speed weaken the vertical mixing and strengthen the structure of the stratification, which interrupts the transport of the substances. However, how much the change of each climate element can influence the structure of the stratification is not clarified. Therefore, it is important to evaluate the effects of each element on the stratification quantitatively. In the present study, we investigated the effect of the change in air temperature and wind speed on the seasonal change of stratification in Lake Biwa by using a three-dimensional hydrodynamic model. Numerical simulations were carried out for a baseline case using realistic meteorological data from 2007 to 2012 and hypothetical cases using meteorological data with modified air temperature or wind speed for sensitivity analysis. The analysis showed that the increase and decrease in air temperature changed the vertical water temperature uniformly in almost all layers. Thus, the strength of the stratification is hardly changed. The increase and decrease in wind speed, however, altered the water temperature near the surface of the lake, so that it significantly influenced the stratification. The increase in wind speed made the water parcels of the surface layer well mixed, and the decrease in wind speed made the mixed layer thinner. Full article
(This article belongs to the Section Hydrology)
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Open AccessArticle Control of Tropical Landcover and Soil Properties on Landslides’ Aquifer Recharge, Piezometry and Dynamics
Water 2018, 10(10), 1491; https://doi.org/10.3390/w10101491
Received: 31 July 2018 / Revised: 1 October 2018 / Accepted: 15 October 2018 / Published: 22 October 2018
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Abstract
Among the processes controlling landslide dynamics, piezometry plays a major role. The characterization of a landslide’s aquifer recharge (=inflows) is thus indispensable for predicting displacements. In this research, the recharge of the large Grand Ilet landslide in the humid tropical, Reunion Island was
[...] Read more.
Among the processes controlling landslide dynamics, piezometry plays a major role. The characterization of a landslide’s aquifer recharge (=inflows) is thus indispensable for predicting displacements. In this research, the recharge of the large Grand Ilet landslide in the humid tropical, Reunion Island was characterized through a multi-disciplinary and robust hydrological approach, notably comprising a precise water budget of the landslide (outflows = inflows). Surface processes play a major role in the landslide recharge regime. Runoff is less than 1% of rainfall (2400 mm/year) due to the soil’s high permeability. A large quantity of water (250 mm) is adsorbed in this shallow layer. This reservoir is submitted to high real evapotranspiration (1500 mm/year) due to the dense tropical broad-leaved vegetation. This explains the low aquifer recharge (860 mm/year), the fact that only major rainfall episodes during the rainy season induce recharge, with a consequent increase in landslide velocity, and finally low outflow from the landslide. Therefore, among other operational recommendations, it is necessary to maintain natural vegetation cover over such landslide surface in order to limit aquifer recharge and thus displacements. This study provides a methodological framework for landslide studies, particularly for modeling their recharge/piezometry, and key parameters of their dynamics. Full article
(This article belongs to the Special Issue Landslide Hydrology)
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Open AccessArticle Climate Change and Curtailment: Evaluating Water Management Practices in the Context of Changing Runoff Regimes in a Snowmelt-Dominated Basin
Water 2018, 10(10), 1490; https://doi.org/10.3390/w10101490
Received: 26 August 2018 / Revised: 16 October 2018 / Accepted: 17 October 2018 / Published: 22 October 2018
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Abstract
Hydrologic scientists and water resource managers often focus on different facets of flow regimes in changing climates. The objective of this work is to examine potential hydrological changes in the Upper Boise River Basin, Idaho, USA in the context of biophysical variables and
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Hydrologic scientists and water resource managers often focus on different facets of flow regimes in changing climates. The objective of this work is to examine potential hydrological changes in the Upper Boise River Basin, Idaho, USA in the context of biophysical variables and their impacts a key variable governing administration of water resources in the region in an integrated way. This snowmelt-dominated, mountainous watershed supplies water to a semi-arid, agriculturally intensive, but rapidly urbanizing, region. Using the Envision integrated modeling framework, we created a hydrological model to simulate hydrological response to the year 2100 using six alternative future climate trajectories. Annual discharge increased from historical values by 6–24% across all simulations (with an average 13% increase), reflecting an increase in precipitation in the climate projections. Discharge peaked 4–33 days earlier and streamflow center of timing occurred 4–17 days earlier by midcentury. Examining changes in the date junior water rights holders begin to be curtailed regionally (the Day of Allocation), we found that the it occurs at least 14 days earlier by 2100 across all simulations, with one suggesting it could occur over a month earlier. These results suggest that current methods and policies of water rights accounting and management may need to be revised moving into the future. Full article
(This article belongs to the Section Water Resources Management and Governance)
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Open AccessArticle The Optimal Width and Mechanism of Riparian Buffers for Storm Water Nutrient Removal in the Chinese Eutrophic Lake Chaohu Watershed
Water 2018, 10(10), 1489; https://doi.org/10.3390/w10101489
Received: 28 September 2018 / Revised: 15 October 2018 / Accepted: 17 October 2018 / Published: 22 October 2018
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Abstract
Riparian buffers play an important role in intercepting nutrients entering lakes from non-point runoffs. In spite of its ecological significance, little is known regarding the underlying mechanisms of riparian buffers or their optimal width. In this study, we examined nutrient removal efficiency, including
[...] Read more.
Riparian buffers play an important role in intercepting nutrients entering lakes from non-point runoffs. In spite of its ecological significance, little is known regarding the underlying mechanisms of riparian buffers or their optimal width. In this study, we examined nutrient removal efficiency, including the quantity of nutrients and water quality, in the littoral zone of different types of riparian buffers in the watershed around eutrophic Lake Chaohu (China), and estimated the optimal width for different types of riparian buffers for effective nutrient removal. In general, a weak phosphorus (P) adsorption ability and nitrification-denitrification potential in soil resulted in a far greater riparian buffer demand than before in Lake Chaohu, which may be attributed to the soil degradation and simplification of cover vegetation. In detail, the width was at least 23 m (grass/forest) and 130 m (grass) for total P (TP) and total nitrogen (TN) to reach 50% removal efficiency, respectively, indicating a significantly greater demand for TN removal than that for TP. Additionally, wetland and grass/forest riparian buffers were more effective for TP removal, which was attributed to a high P sorption maximum (Qmax) and a low equilibrium P concentration (EPC0), respectively. The high potential nitrification rate (PNR) and potential denitrification rate (PDR) were responsible for the more effective TN removal efficiencies in grass riparian buffers. The nutrient removal efficiency of different types of riparian buffers was closely related with nutrient level in adjacent littoral zones around Lake Chaohu. Full article
(This article belongs to the Special Issue Lake and River Restoration: Method, Evaluation and Management)
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Open AccessArticle Reduction and Accumulative Characteristics of Dissolved Heavy Metals in Modified Bioretention Media
Water 2018, 10(10), 1488; https://doi.org/10.3390/w10101488
Received: 25 July 2018 / Revised: 16 October 2018 / Accepted: 17 October 2018 / Published: 22 October 2018
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Abstract
Twelve bioretention filter columns with different media were designed to study the effects of media on dissolved heavy metals in bioretention systems by changing three test conditions (inflow concentration, discharge ratio, and recurrence interval). The results showed that the average load reduction efficiency
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Twelve bioretention filter columns with different media were designed to study the effects of media on dissolved heavy metals in bioretention systems by changing three test conditions (inflow concentration, discharge ratio, and recurrence interval). The results showed that the average load reduction efficiency of the bioretention soil media (BSM)+10%water treatment residue, BSM+10%green zeolite, and BSM+10%medicinal stone for Cu and Zn was larger than 80%. The highest volume reduction efficiency is 39.25% by BSM+coconut bran. Among the three factors selected in tests, inflow concentration had the biggest degree of influence, followed by discharge ratio and recurrence interval. The media of the upper, middle, and lower layers of each filter column were detected before and after the treatment to study the accumulative characteristics of heavy metals in the bioretention system. The accumulation of Cu, Zn, and Cd in the media of BSM+medicinal stone, BSM+fly ash, BSM+vermiculite, and BSM+turfy soil was relatively low. The contents of the three metals were positively correlated with urease and negatively correlated with protease in the media, but no obvious rule was showed in the accumulation of dissolved heavy metals with depth. Full article
(This article belongs to the Section Urban Water Management)
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Open AccessArticle Relationship between the Distribution of Broodstock and Vorticity of Spawning Grounds of Four Major Chinese Carps in the Middle Reaches of the Yangtze River during Ecological Operation of the Three Gorges Dam
Water 2018, 10(10), 1487; https://doi.org/10.3390/w10101487
Received: 30 August 2018 / Revised: 28 September 2018 / Accepted: 18 October 2018 / Published: 22 October 2018
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Abstract
Hydrodynamic characteristics of spawning grounds are important factors affecting the spawning of four major Chinese carps (Mylopharyngodon piceus, Ctenopharyngodon idella, Hypophthalmichthys molitrix, and Aristichthys nobilis). To investigate the relationship between the preferred hydrodynamic characteristics of spawning sites and
[...] Read more.
Hydrodynamic characteristics of spawning grounds are important factors affecting the spawning of four major Chinese carps (Mylopharyngodon piceus, Ctenopharyngodon idella, Hypophthalmichthys molitrix, and Aristichthys nobilis). To investigate the relationship between the preferred hydrodynamic characteristics of spawning sites and the response of fish spawning behavior, we monitored the flow field of spawning sites during ecological operation of the Three Gorges Dam (i.e., man-made flood regulation) in 2014 and 2015. We used the data to explore the correlation between vorticity changes in spawning grounds and the spawning amount. Pearson correlation coefficients of the average vorticity in all cross-sections of the Yidu spawning ground and spawning amount in 2014 and 2015 were 0.730 and 0.822, respectively, indicating a significant positive correlation between vorticity and spawning activity. In some specific regions, this correlation was even stronger (Pearson correlations of the regional vorticity and egg production were >0.95). To further corroborate and analyze the relationship between these specific regions and the distribution of broodstock during the breeding season, an ultrasonic telemetry test of broodstock was conducted in the Yidu spawning ground in 2016. The results showed that the broodstocks were concentrated in the reach near the Quantong Pier (~76 km from the Three Gorges Dam). These regions were consistent with areas of river characterized by highly correlated vorticity and egg production levels, suggesting that these regions are areas preferred by four major Chinese carps for spawning. Full article
(This article belongs to the Section Hydrology)
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Open AccessArticle Monthly Streamflow Forecasting Using EEMD-Lasso-DBN Method Based on Multi-Scale Predictors Selection
Water 2018, 10(10), 1486; https://doi.org/10.3390/w10101486
Received: 3 October 2018 / Revised: 15 October 2018 / Accepted: 18 October 2018 / Published: 22 October 2018
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Abstract
For the inherent characteristics of a raw streamflow times series and the complicated relationship between multi-scale predictors and streamflow, monthly streamflow forecasting is very difficult. In this paper, an method was proposed integrating the ensemble empirical mode decomposition (EEMD), least absolute shrinkage and
[...] Read more.
For the inherent characteristics of a raw streamflow times series and the complicated relationship between multi-scale predictors and streamflow, monthly streamflow forecasting is very difficult. In this paper, an method was proposed integrating the ensemble empirical mode decomposition (EEMD), least absolute shrinkage and selection operator (Lasso) with deep belief networks (DBN) for forecasting monthly streamflow time series, which is EEMD-Lasso-DBN (ELD) method. To develop the ELD model, the raw streamflow time series was resolved into different elements, including intrinsic mode functions (IMFs) and residue series, using the EEMD technique. The predictors of each IMF element and residue were screened using the Lasso technique from a large number of candidate predictors, respectively. Then, the DBN models were built to simulate the complex relationship between the resolved elements and the selected predictors, respectively. The predicted results of the IMFs and residual series were assembled as an ensemble forecast for the raw streamflow time series and were compared with the other models. The monthly streamflow series from Tennessee, in the USA, were investigated using the ELD method. It was found that each IMF has different characteristics and physical meaning, corresponding to different predictors. The proposed ELD model can significantly improve the accuracy of monthly streamflow forecasting. Full article
(This article belongs to the Section Hydrology)
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Open AccessTechnical Note Extraction of Urban Waterlogging Depth from Video Images Using Transfer Learning
Water 2018, 10(10), 1485; https://doi.org/10.3390/w10101485
Received: 25 September 2018 / Revised: 18 October 2018 / Accepted: 19 October 2018 / Published: 21 October 2018
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Abstract
Urban flood control requires real-time and spatially detailed information regarding the waterlogging depth over large areas, but such information cannot be effectively obtained by the existing methods. Video supervision equipment, which is readily available in most cities, can record urban waterlogging processes in
[...] Read more.
Urban flood control requires real-time and spatially detailed information regarding the waterlogging depth over large areas, but such information cannot be effectively obtained by the existing methods. Video supervision equipment, which is readily available in most cities, can record urban waterlogging processes in video form. These video data could be a valuable data source for waterlogging depth extraction. The present paper is aimed at demonstrating a new approach to extract urban waterlogging depths from video images based on transfer learning and lasso regression. First, a transfer learning model is used to extract feature vectors from a video image set of urban waterlogging. Second, a lasso regression model is trained with these feature vectors and employed to calculate the waterlogging depth. Two case studies in China were used to evaluate the proposed method, and the experimental results illustrate the effectiveness of the method. This method can be applied to video images from widespread cameras in cities, so that a powerful urban waterlogging monitoring network can be formed. Full article
(This article belongs to the Special Issue Flash Floods in Urban Areas)
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Open AccessArticle Monitoring Temporal Change of River Islands in the Yangtze River by Remotely Sensed Data
Water 2018, 10(10), 1484; https://doi.org/10.3390/w10101484
Received: 8 September 2018 / Revised: 25 September 2018 / Accepted: 18 October 2018 / Published: 21 October 2018
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Abstract
The spatial extent and area of river islands are always changing due to the impact of hydrodynamic conditions, sediment supply and human activities. A catastrophic flood disaster was driven by sustained and heavy rainfall around the middle and lower Yangtze River in 18
[...] Read more.
The spatial extent and area of river islands are always changing due to the impact of hydrodynamic conditions, sediment supply and human activities. A catastrophic flood disaster was driven by sustained and heavy rainfall around the middle and lower Yangtze River in 18 June to 21 July 2016. The flood resulted in the most serious social-economic loss since 1954 and caused a larger-scale inundation for a short time. It is essential to continuously monitor the dynamics changes of river islands because this can avoid frequent field measurements in river islands before and after flood disasters, which are helpful for flood warning. This paper focuses on the temporal change of three river islands called Fenghuangzhou, Changshazhou, and one uninhabited island in the Yangtze River in 2016. In this study, GF-1 (GaoFen-1) WFV (wide field view) data was used for our study owing to its fine spatial and temporal resolution. A simple NDWI (Normalized Difference Water Index) method was used for the river island mapping. Human checking was then performed to ensure mapping accuracy. We estimated the relationship between the area of river islands and measured water levels using four models. Furthermore, we mapped the spatial pattern of inundation risk of river islands. The results indicate a good ability of the GF-1 WFV data with a 16-m spatial resolution to characterize the variation of river islands and to study the association between flood disaster and river islands. A significantly negative but nonlinear relationship between the water level and the area of the river island was observed. We also found that the cubic function fits best among three models (R2 > 0.8, P < 0.001). The maximum of the inundated area at the river island appeared in the rainy season on 8 July 2016 and the minimum occurred in the dry season on 28 December 2016, which is consistent with the water level measured by the hydrological station. Our results derived from GF-1 data can provide a useful reference for decision-making of flood warning, disaster assessment, and post-disaster reconstruction. Full article
(This article belongs to the Section Hydrology)
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Open AccessArticle Infilling Missing Data in Hydrology: Solutions Using Satellite Radar Altimetry and Multiple Imputation for Data-Sparse Regions
Water 2018, 10(10), 1483; https://doi.org/10.3390/w10101483
Received: 6 September 2018 / Revised: 5 October 2018 / Accepted: 10 October 2018 / Published: 20 October 2018
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Abstract
In developing regions missing data are prevalent in historical hydrological datasets, owing to financial, institutional, operational and technical challenges. If not tackled, these data shortfalls result in uncertainty in flood frequency estimates and consequently flawed catchment management interventions that could exacerbate the impacts
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In developing regions missing data are prevalent in historical hydrological datasets, owing to financial, institutional, operational and technical challenges. If not tackled, these data shortfalls result in uncertainty in flood frequency estimates and consequently flawed catchment management interventions that could exacerbate the impacts of floods. This study presents a comparative analysis of two approaches for infilling missing data in historical annual peak river discharge timeseries required for flood frequency estimation: (i) satellite radar altimetry (RA) and (ii) multiple imputation (MI). These techniques were applied at five gauging stations along the floodprone Niger and Benue rivers within the Niger River Basin. RA and MI enabled the infilling of missing data for conditions where altimetry virtual stations were available and unavailable, respectively. The impact of these approaches on derived flood estimates was assessed, and the return period of a previously unquantified devastating flood event in Nigeria in 2012 was ascertained. This study revealed that the use of RA resulted in reduced uncertainty when compared to MI for data infilling, especially for widely gapped timeseries (>3 years). The two techniques did not differ significantly for data sets with gaps of 1–3 years, hence, both RA and MI can be used interchangeably in such situations. The use of the original in situ data with gaps resulted in higher flood estimates when compared to datasets infilled using RA and MI, and this can be attributed to extrapolation uncertainty. The 2012 flood in Nigeria was quantified as a 1-in-100-year event at the Umaisha gauging station on the Benue River and a 1-in-50-year event at Baro on the Niger River. This suggests that the higher levels of flooding likely emanated from the Kiri and Lagdo dams in Nigeria and Cameroon, respectively, as previously speculated by the media and recent studies. This study demonstrates the potential of RA and MI for providing information to support flood management in developing regions where in situ data is sparse. Full article
(This article belongs to the Special Issue Hydrologic Modelling for Water Resources and River Basin Management)
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Open AccessArticle Evaluation of Water Scarcity in Selected Countries of the Middle East
Water 2018, 10(10), 1482; https://doi.org/10.3390/w10101482
Received: 10 September 2018 / Revised: 16 October 2018 / Accepted: 16 October 2018 / Published: 20 October 2018
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Abstract
The primary goal of this article is to evaluate water scarcity in selected countries of the Middle-East and assess the impact on agricultural production. To begin with, the Weighted Anomaly Standardized Precipitation (WASP) Index from 1979 to 2017 was spatially computed for Iran,
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The primary goal of this article is to evaluate water scarcity in selected countries of the Middle-East and assess the impact on agricultural production. To begin with, the Weighted Anomaly Standardized Precipitation (WASP) Index from 1979 to 2017 was spatially computed for Iran, Iraq and Saudi Arabia. In order to demonstrate the effect of reduced levels of water, the water shortage situation in cities with the population higher than one million was examined. This was accomplished by utilizing the Composite Index approach to make water related statistics more intelligible. A projection for the years of 2020 to 2030 was created in order to demonstrate possible changes in the supply and demand for water in selected countries of the Middle-East. In regards to evaluating the economic effects of water shortages on agricultural sector, effects of lower precipitation on agricultural production in Iran, Iraq and Saudi Arabia were estimated. With ever-increasing urbanization, all countries are currently experiencing a moderate to high water risk. Our research points to excessively high water stress for most analyzed cities through the year 2030. Also, it is demonstrated how much precipitation decreases influence agricultural production in Iran, Iraq and Saudi Arabia. From the analyzed countries, some evidence is found that precipitation negatively influences crop production, primarily for Iran. Full article
(This article belongs to the Section Water Use and Scarcity)
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Open AccessArticle Exploring the Statistical and Distributional Properties of Residential Water Demand at Fine Time Scales
Water 2018, 10(10), 1481; https://doi.org/10.3390/w10101481
Received: 30 August 2018 / Revised: 15 October 2018 / Accepted: 17 October 2018 / Published: 19 October 2018
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Abstract
Residential water demand consists one of the most uncertain factors posing extra difficulties in the efficient planning and management of urban water systems. Currently, high resolution data from smart meters provide the means for a better understanding and modelling of this variable at
[...] Read more.
Residential water demand consists one of the most uncertain factors posing extra difficulties in the efficient planning and management of urban water systems. Currently, high resolution data from smart meters provide the means for a better understanding and modelling of this variable at a household level and fine temporal scales. Having this in mind, this paper examines the statistical and distributional properties of residential water demand at a 15-minute and hourly scale, which are the temporal scales of interest for the majority of urban water modeling applications. Towards this, we investigate large residential water demand records of different characteristics. The analysis indicates that the studied characteristics of the marginal distribution of water demand vary among households as well as on the basis of different time intervals. Both month-to-month and hour-to-hour analysis reveal that the mean value and the probability of no demand exhibit high variability while the changes in the shape characteristics of the marginal distributions of the nonzero values are significantly less. The investigation of performance of 10 probabilistic models reveals that Gamma and Weibull distributions can be used to adequately describe the nonzero water demand records of different characteristics at both time scales. Full article
(This article belongs to the Special Issue Water Networks Management: New Perspectives)
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Open AccessArticle Hurricanes as a Major Driver of Coastal Erosion in the Mississippi River Delta: A Multi-Decadal Analysis of Shoreline Retreat Rates at Bay Champagne, Louisiana (USA)
Water 2018, 10(10), 1480; https://doi.org/10.3390/w10101480
Received: 24 September 2018 / Revised: 13 October 2018 / Accepted: 16 October 2018 / Published: 19 October 2018
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Abstract
The Louisiana shoreline is rapidly retreating as a result of factors such as sea-level rise and land subsidence. The northern Gulf of Mexico coast is also a hotspot for hurricane landfalls, and several major storms have impacted this region in the past few
[...] Read more.
The Louisiana shoreline is rapidly retreating as a result of factors such as sea-level rise and land subsidence. The northern Gulf of Mexico coast is also a hotspot for hurricane landfalls, and several major storms have impacted this region in the past few decades. A section of the Louisiana (USA) coast that has one of the highest rates of shoreline retreat in North America is the Caminada-Moreau headland, located south of New Orleans. Bay Champagne is a coastal lake within the headland that provides a unique opportunity to investigate shoreline retreat and the coastal effects of hurricanes. In order to examine the influence of hurricanes on the rate of shoreline retreat, 35 years (1983–2018) of Landsat imagery was analyzed. During that period of time, the shoreline has retreated 292 m. The overall rate of shoreline retreat, prior to a beach re-nourishment project completed in 2014, was over 12 m per year. A period of high hurricane frequency (1998–2013) corresponds to an increased average shoreline retreat rate of >21 m per year. Coastal features created by multiple hurricanes that have impacted this site have persisted for several years. Bay Champagne has lost 48% of its surface area over the last 35 years as a result of long-term shoreline retreat. If shoreline retreat continues at the average rate, it is expected that Bay Champagne will disappear completely within the next 40 years. Full article
(This article belongs to the Special Issue Recent Progress in Research on River Deltas)
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Open AccessArticle Relationships Among Animal Communities, Lentic Habitats, and Channel Characteristics for Ecological Sediment Management
Water 2018, 10(10), 1479; https://doi.org/10.3390/w10101479
Received: 29 August 2018 / Revised: 15 October 2018 / Accepted: 16 October 2018 / Published: 19 October 2018
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Abstract
This study used a multiscale analysis of relationships among the bitterling and mussel communities, lentic habitat structures with conditions and flooding frequency, and channel characteristics for application in ecological sediment management. From the Kizu River in Japan, 120 lentic habitats were sampled in
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This study used a multiscale analysis of relationships among the bitterling and mussel communities, lentic habitat structures with conditions and flooding frequency, and channel characteristics for application in ecological sediment management. From the Kizu River in Japan, 120 lentic habitats were sampled in 2007 and 2010. The floodplain vertical shape index (FVSI), which indicates the degree of convexity or concavity of the vertical shape of a floodplain, was used as channel characteristics using historical cross-section profiles obtained from 1960 to 2012. For examining the relationships between bitterlings/mussels and each habitat condition or structure, abundance values of bitterlings and mussels were transformed into habitat suitability index (HSI). Furthermore, the relationships between the number of habitat structures and FVSI were analyzed. The results indicated that bitterlings and mussels are more abundant in terrace ponds than in active ponds, especially so in terrace ponds located in the lower area of bars with a flooding frequency of 8–16 days/year (bitterlings), those located in the lower area of bars with a flooding frequency of 8 days/year, and those located in the upper area of bars with a flooding frequency of 16–22 days/year (mussels). These ponds tended to have less than 1 cm mud depth that was negatively related to abundance of mussels. These suitable habitat types tended to be located in channels with a floodplain vertical shape index between −0.35 and 0.05. We established countermeasures to prevent channel types with floodplain vertical shape index exceeding 0.05 instead of restoring the previous channel conditions. Full article
(This article belongs to the Special Issue Adaptive Catchment Management and Reservoir Operation)
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Open AccessArticle Numerical Investigation on the Hydraulic Properties of the Skimming Flow over Pooled Stepped Spillway
Water 2018, 10(10), 1478; https://doi.org/10.3390/w10101478
Received: 21 September 2018 / Revised: 4 October 2018 / Accepted: 15 October 2018 / Published: 19 October 2018
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Abstract
Pooled stepped spillway is known for high aeration efficiency and energy dissipation, but the understanding for the effects of pool weir configuration on the flow properties and energy loss is relatively limited, so RNG kε εturbulence model with VOF method was
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Pooled stepped spillway is known for high aeration efficiency and energy dissipation, but the understanding for the effects of pool weir configuration on the flow properties and energy loss is relatively limited, so RNG k ε εturbulence model with VOF method was employed to simulate the hydraulic characteristics of the stepped spillways with four types of pool weirs. The calculated results suggested the flow in the stepped spillway with staggered configuration of` two-sided pooled and central pooled steps (TP-CP) was highly three dimensional and created more flow instabilities and vortex structures, leading to 1.5 times higher energy dissipation rate than the fully pooled configuration (FP-FP). In FP-FP configuration, the stepped spillway with fully pooled and two-sided pooled steps (FP-TP) and the spillway with fully pooled and central pooled steps (FP-CP), the pressure on the horizontal step surfaces presented U-shaped variation, and TP-CP showed the greatest pressure fluctuation. For FP-TP and FP-CP, the vortex development in the transverse direction presented the opposite phenomenon, and the maximum vortex intensity in TP-CP occurred at Z/W = 0.25, while FP-FP illustrated no significant change in the transverse direction. The overlaying flow velocity distribution in the spanwise direction demonstrated no obvious difference among FP-FP, FP-TP, and FP-CP, while the velocity in TP-CP increased from the axial plane to the sidewalls, but the maximum velocity for all cases were approximately the same. Full article
(This article belongs to the Special Issue Advances in Hydraulics and Hydroinformatics)
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Open AccessArticle Stationary and Non-Stationary Frameworks for Extreme Rainfall Time Series in Southern Italy
Water 2018, 10(10), 1477; https://doi.org/10.3390/w10101477
Received: 16 August 2018 / Revised: 11 October 2018 / Accepted: 17 October 2018 / Published: 19 October 2018
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Abstract
This study tests stationary and non-stationary approaches for modelling data series of hydro-meteorological variables. Specifically, the authors considered annual maximum rainfall accumulations observed in the Calabria region (southern Italy), and attention was focused on time series characterized by heavy rainfall events which occurred
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This study tests stationary and non-stationary approaches for modelling data series of hydro-meteorological variables. Specifically, the authors considered annual maximum rainfall accumulations observed in the Calabria region (southern Italy), and attention was focused on time series characterized by heavy rainfall events which occurred from 1 January 2000 in the study area. This choice is justified by the need to check if the recent rainfall events in the new century can be considered as very different or not from the events occurred in the past. In detail, the whole data set of each considered time series (characterized by a sample size N > 40 data) was analyzed, in order to compare recent and past rainfall accumulations, which occurred in a specific site. All the proposed models were based on the Two-Component Extreme Value (TCEV) probability distribution, which is frequently applied for annual maximum time series in Calabria. The authors discussed the possible sources of uncertainty related to each framework and remarked on the crucial role played by ergodicity. In fact, if the process is assumed to be non-stationary, then ergodicity cannot hold, and thus possible trends should be derived from external sources, different from the time series of interest: in this work, Regional Climate Models’ (RCMs) outputs were considered in order to assess possible trends of TCEV parameters. From the obtained results, it does not seem essential to adopt non-stationary models, as significant trends do not appear from the observed data, due to a relevant number of heavy events which also occurred in the central part of the last century. Full article
(This article belongs to the Section Hydrology)
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Open AccessArticle The Impact of River Discharge and Water Temperature on Manganese Release from the Riverbed during Riverbank Filtration: A Case Study from Dresden, Germany
Water 2018, 10(10), 1476; https://doi.org/10.3390/w10101476
Received: 19 July 2018 / Revised: 10 October 2018 / Accepted: 15 October 2018 / Published: 19 October 2018
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Abstract
The climate-related variables, river discharge, and water temperature, are the main factors controlling the quality of the bank filtrate by affecting infiltration rates, travel times, and redox conditions. The impact of temperature and discharge on manganese release from a riverbed were assessed by
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The climate-related variables, river discharge, and water temperature, are the main factors controlling the quality of the bank filtrate by affecting infiltration rates, travel times, and redox conditions. The impact of temperature and discharge on manganese release from a riverbed were assessed by water quality data from a monitoring transect at a riverbank filtration site in Dresden-Tolkewitz. Column experiments with riverbed material were used to assess the Mn release for four temperature and three discharge conditions, represented by varying infiltration rates. The observed Mn release was modeled as kinetic reactions via Monod-type rate formulations in PHREEQC. The temperature had a bigger impact than the infiltration rates on the Mn release. Infiltration rates of <0.3 m3/(m2·d) required temperatures >20 °C to trigger the Mn release. With increasing temperatures, the infiltration rates became less important. The modeled consumption rates of dissolved oxygen are in agreement with results from other bank filtration sites and are potentially suited for the further application of the given conditions. The determined Mn reduction rate constants were appropriate to simulate Mn release from the riverbed sediments but seemed not to be suited for simulations in which Mn reduction is likely to occur within the aquifer. Sequential extractions revealed a decrease of easily reducible Mn up to 25%, which was found to reflect the natural stratification within the riverbed, rather than a depletion of the Mn reservoir. Full article
(This article belongs to the Special Issue Efficiency of Bank Filtration and Post-Treatment)
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Open AccessFeature PaperArticle Discovering the Political Implications of Coproduction in Water Governance
Water 2018, 10(10), 1475; https://doi.org/10.3390/w10101475
Received: 17 August 2018 / Revised: 14 October 2018 / Accepted: 17 October 2018 / Published: 19 October 2018
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Abstract
This paper asks what lessons can be learned from experiences with coproduction in water governance. For this, we review a comprehensive corpus of articles in the field of water governance that relies on the term. We find that there are radically different understandings
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This paper asks what lessons can be learned from experiences with coproduction in water governance. For this, we review a comprehensive corpus of articles in the field of water governance that relies on the term. We find that there are radically different understandings of what coproduction means in different branches of the water governance literature. Through this review, we demonstrate how and why coproduction needs to be analyzed for its political implications. Despite being timely and pressing, these questions are not addressed in a sufficient way by the scholarly debate on coproduction. In order to fill this knowledge gap, we first distinguish different historical traditions of coproduction and then explore their political implications along three questions: The “why?”, the “who?”, and the “how?”. We show that these questions find different answers not just between but also within different traditions of using the term. After describing and contrasting these variants, we conclude by summarizing the main lessons from our review and by identifying questions which call for future research. Full article
Open AccessArticle Water Protection Zoning as an Instrument of Preservation for Lake Baikal
Water 2018, 10(10), 1474; https://doi.org/10.3390/w10101474
Received: 29 August 2018 / Revised: 15 October 2018 / Accepted: 17 October 2018 / Published: 19 October 2018
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Abstract
The article is dedicated to the justification and practical implementation of a nature protection-based methodological approach to define the boundaries of the Lake Baikal protection zone and form proposals related to the harmonization of instruments of environmentally responsible development of the territory, which
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The article is dedicated to the justification and practical implementation of a nature protection-based methodological approach to define the boundaries of the Lake Baikal protection zone and form proposals related to the harmonization of instruments of environmentally responsible development of the territory, which has the status of a World Heritage site as it contains 20% of the world’s fresh water supply. An analysis of the contemporary conditions of Lake Baikal and its surrounding landscapes show environmental degradation of the area. The most important aspects in solving the existing problem may be the construction of a science-based definition of the Lake Baikal water protection zone and compliance with the universal global values related to the requirements of ecological threat prevention. The main landscape-hydrological design principles for the water protection zone are studied in this article. A method for the functional water protection zoning of urban territories is also given. This has been implemented in Baikalsk town, which is located on the Baikal shore and is considered to be one of the most environmentally damaged territories. Proposals include recommendations on the harmonization of the landscape-hydrological principles of territory assessment and methods for target landscape planning; the setting of various restrictions within the boundaries of existing industrial and settlement zones; the creation of an overall system of environmental health monitoring for Lake Baikal and its protection zones; and for ensuring interactions with the public. Full article
(This article belongs to the Section Water Resources Management and Governance)
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Open AccessArticle Characteristics of Positive Surges in a Rectangular Channel
Water 2018, 10(10), 1473; https://doi.org/10.3390/w10101473
Received: 17 September 2018 / Revised: 9 October 2018 / Accepted: 16 October 2018 / Published: 19 October 2018
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Abstract
A positive surge is an unsteady open channel flow motion characterized by an increase of flow depth. In previous experimental studies, a positive surge was typically induced by either a sudden increase of discharge in a channel or by the rapid closure of
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A positive surge is an unsteady open channel flow motion characterized by an increase of flow depth. In previous experimental studies, a positive surge was typically induced by either a sudden increase of discharge in a channel or by the rapid closure of a downstream sluice gate, thus leading to a steep initial profile. However, in many instances, the evolution of a positive surge is of a progressive manner (e.g., in the downstream navigation canal during the emptying operation of lock chambers). In the present work, the inception and development of a positive surge induced by a progressive increase of discharge was investigated in a rectangular channel with a smooth bed. Both undular and breaking surges were studied. The results demonstrate that the maximum wave height at the first wave crest of an undular surge is in very close agreement with the McCowan theory. Additionally, the wave amplitude essentially shows a linearly increasing trend with an increasing surge Froude number up to Fr0 = 1.26 to 1.28, whereas it tends to suggest a power law reduction for larger surge Froude numbers. Moreover, the dispersion of undular surges is consistent with the linear wave theory only for surge Froude numbers close to unity. Overall, the present study demonstrates the unique features of positive surges induced by a progressive increase of discharge. Full article
(This article belongs to the Section Hydraulics)
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Open AccessArticle Gender and Community Mainstreaming in Fog Water Collection Systems
Water 2018, 10(10), 1472; https://doi.org/10.3390/w10101472
Received: 17 August 2018 / Revised: 26 September 2018 / Accepted: 11 October 2018 / Published: 19 October 2018
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Abstract
Fog water collection is an emerging opportunity to combat local water shortages in water-scarce areas where sustainable access to water is unreliable, but fog events are frequent. Since fog water systems are implemented within or near communities, they eliminate or decrease the need
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Fog water collection is an emerging opportunity to combat local water shortages in water-scarce areas where sustainable access to water is unreliable, but fog events are frequent. Since fog water systems are implemented within or near communities, they eliminate or decrease the need to travel far distances for the collection of water during times of scarcity. As a result, these systems decrease the physical and social burden of water collection on women and girls, who are the primary water gatherers in most traditional communities. This is an important outcome because women and girls are disproportionately affected by water scarcity and are not seen as equals in water management, access, or control. This paper illustrates how several fog water collection projects have shown, empirically, that the positive outcomes for women and girls may include the freeing of time for domestic and educational pursuits, improved health outcomes, and improved perceptions of self and others’ perceptions of women. These findings are important at a time when the world at large is addressing the Sustainable Development Agenda, where Sustainable Development Goal (SDG) 6 necessitates safe water and sanitation for all and SDG 5 ensures gender equality to empower all women and girls. Full article
(This article belongs to the Section Water Use and Scarcity)
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Open AccessArticle Daily Water Quality Forecast of the South-To-North Water Diversion Project of China Based on the Cuckoo Search-Back Propagation Neural Network
Water 2018, 10(10), 1471; https://doi.org/10.3390/w10101471
Received: 21 September 2018 / Revised: 13 October 2018 / Accepted: 15 October 2018 / Published: 18 October 2018
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Abstract
Water quality forecast is a critical part of water security management. Spatiotemporal and multifactorial variations make water quality very complex and changeable. In this article, a novel model, which was based on back propagation neural network that was optimized by the Cuckoo Search
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Water quality forecast is a critical part of water security management. Spatiotemporal and multifactorial variations make water quality very complex and changeable. In this article, a novel model, which was based on back propagation neural network that was optimized by the Cuckoo Search algorithm (hereafter CS-BP model), was applied to forecast daily water quality of the Middle Route of South-to-North Water Diversion Project of China. Nine water quality indicators, including conductivity, chlorophyll content, dissolved oxygen, dissolved organic matter, pH, permanganate index, turbidity, total nitrogen, and water temperature were the predictand. Seven external environmental factors, including air temperature, five particulate matter (PM2.5), rainfall, sunshine duration, water flow, wind velocity, and water vapor pressure were the default predictors. A data pre-processing method was applied to select pertinent predictors. The results show that the CS-BP model has the best forecast accuracy, with the Mean Absolute Percentage Errors (MAPE) of 0.004%–0.33%, and the lowest Root Mean Square Error (RMSE) of each water quality indicator in comparison with traditional Back Propagation (BP) model, General Regression Neural Network model and Particle Swarm Optimization-Back Propagation model under default data proportion, 150:38 (training data: testing data). When training data reduced from 150 to 140, and from 140 to 130, the CS-BP model still produced the best forecasts, with the MAPEs of 0.014%–0.057% and 0.004%–1.154%, respectively. The results show that the CS-BP model can be an effective tool in daily water quality forecast with limited observed data. The improvement of the Cuckoo Search algorithm such as calculation speed, the forecast errors reduction of the CS-BP model, and the large-scale impacts such as land management on different water quality indicators, will be the focus of future research. Full article
(This article belongs to the Section Water Quality and Ecosystems)
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Open AccessArticle Analysis of Flood Risk of Urban Agglomeration Polders Using Multivariate Copula
Water 2018, 10(10), 1470; https://doi.org/10.3390/w10101470
Received: 13 September 2018 / Revised: 3 October 2018 / Accepted: 16 October 2018 / Published: 18 October 2018
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Abstract
Urban agglomeration polders (UAPs) are often used to control flooding in eastern China. The impacts of UAPs on individual flood events have been extensively examined, but how flood risks are influenced by UAPs is much less examined. This study aimed to explore a
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Urban agglomeration polders (UAPs) are often used to control flooding in eastern China. The impacts of UAPs on individual flood events have been extensively examined, but how flood risks are influenced by UAPs is much less examined. This study aimed to explore a three-dimensional joint distribution of annual flood volume, peak flow and water level to examine UAPs’ impact on flood risks based on hydrological simulations. The dependence between pairwise hydrological characteristics are measured by rank correlation coefficients and graphs. An Archimedean Copula is applied to model the dependence structure. This approach is applied to the Qinhuai River Basin where UAPs are used proactively for flood control. The result shows that the Frank Copula can better represent the dependence structure in the Qinhuai River Basin. UAPs increase risks of individual flood characteristics and integrated risks. UAPs have a relatively greater impact on water level than the other two flood characteristics. It is noted that the impact on flood risk levels off for greater floods. Full article
(This article belongs to the Special Issue Flood Modelling: Regional Flood Estimation and GIS Based Techniques)
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Open AccessArticle Effect of Climate Change on Soil Erosion in a Mountainous Mediterranean Catchment (Central Pindus, Greece)
Water 2018, 10(10), 1469; https://doi.org/10.3390/w10101469
Received: 24 September 2018 / Revised: 16 October 2018 / Accepted: 16 October 2018 / Published: 18 October 2018
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Abstract
The aim of this study was to assess soil erosion changes in the mountainous catchment of the Portaikos torrent (Central Greece) under climate change. To this end, precipitation and temperature data were derived from a high-resolution (25 × 25 km) RegCM3 regional climate
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The aim of this study was to assess soil erosion changes in the mountainous catchment of the Portaikos torrent (Central Greece) under climate change. To this end, precipitation and temperature data were derived from a high-resolution (25 × 25 km) RegCM3 regional climate model for the baseline period 1974–2000 and future period 2074–2100. Additionally, three GIS layers were generated regarding land cover, geology, and slopes in the study area, whereas erosion state was recognized after field observations. Subsequently, the erosion potential model (EPM) was applied to quantify the effects of precipitation and temperature changes on soil erosion. The results showed a decrease (−21.2%) in annual precipitation (mm) and increase (+3.6 °C) in mean annual temperature until the end of the 21st century, and the above changes are likely to lead to a small decrease (−4.9%) in soil erosion potential. Full article
(This article belongs to the Special Issue Erosion and Torrent Control)
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Open AccessArticle Evaluation of Rainfall Temporal Distribution Models with Annual Maximum Rainfall Events in Seoul, Korea
Water 2018, 10(10), 1468; https://doi.org/10.3390/w10101468
Received: 17 September 2018 / Revised: 14 October 2018 / Accepted: 14 October 2018 / Published: 17 October 2018
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Abstract
This study evaluated five models of rainfall temporal distribution (i.e., the Yen and Chow model, Mononobe model, alternating block method, Huff model, and Keifer and Chu model), with the annual maximum rainfall events selected from Seoul, Korea, from 1961 to 2016. Three different
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This study evaluated five models of rainfall temporal distribution (i.e., the Yen and Chow model, Mononobe model, alternating block method, Huff model, and Keifer and Chu model), with the annual maximum rainfall events selected from Seoul, Korea, from 1961 to 2016. Three different evaluation measures were considered: the absolute difference between the rainfall peaks of the model and the observed, the root mean square error, and the pattern correlation coefficient. Also, sensitivity analysis was conducted to determine whether the model, or the randomness of the rainfall temporal distribution, had the dominant effect on the runoff peak flow. As a result, the Keifer and Chu model was found to produce the most similar rainfall peak to the observed, the root mean square error was smaller for the Yen and Chow model and the alternating block method, and the pattern correlation was larger for the alternating block method. Overall, the best model to approximate the annual maximum rainfall events observed in Seoul, Korea, was found to be the alternating block method. Finally, the sensitivity of the runoff peak flow to the model of rainfall temporal distribution was found to be much higher than that to the randomness of the rainfall temporal distribution. In particular, in small basins with a high curve number (CN) value, the sensitivity of the runoff peak flow to the randomness of the rainfall temporal distribution was found to be insignificant. Full article
(This article belongs to the Section Hydrology)
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Open AccessArticle Optimized Water and Fertilizer Management of Mature Jujube in Xinjiang Arid Area Using Drip Irrigation
Water 2018, 10(10), 1467; https://doi.org/10.3390/w10101467
Received: 7 September 2018 / Revised: 12 October 2018 / Accepted: 15 October 2018 / Published: 17 October 2018
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Abstract
Studying water–fertilizer coupling effects in a drip irrigation system is critical for sustainable agricultural development in arid areas, such as that of Xinjiang in China, to find out the optimized water and fertilizer management. Therefore, a two-year field experiment was conducted to find
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Studying water–fertilizer coupling effects in a drip irrigation system is critical for sustainable agricultural development in arid areas, such as that of Xinjiang in China, to find out the optimized water and fertilizer management. Therefore, a two-year field experiment was conducted to find out how the combination of three levels of irrigation quotas and three levels of fertilizer amounts would affect the physiological and growth indexes of jujube, as well as ascertain the differences between drip irrigation and flood irrigation. The results showed that the interacted and coupled effects of irrigation and fertilization influenced most of the physiological indicators and growth indexes. On the other hand, the physiological and growth indexes were increased after transferring flood irrigation to drip irrigation, as the maximum chlorophyll content (CC) and photosynthetic nitrogen use efficiency (PNUE) values increased on average by 6.00%, and 11.39% in 2016, and 1.47% and 6.83% in 2017, respectively. Undoubtedly, inappropriate water and fertilizer management had negative impacts on jujube growth and yield. Based on the treatments and results in this paper, low fertilizer and moderate irrigation would be the best choice. The crop yield, irrigation water use efficiency (iWUE), and fertilizer partial productivity (PFP) increased by 6.77%, 29.48%, and 193.62% in 2016, and similar increments were also found in 2017 of 6.17%, 78.72%, and 133.06%, respectively. This indicated that fertilizer efficiency was promoted along with water use, and in turn, the water amounts were adjusted by the amount of fertilizer that was applied. Based on a comprehensive consideration of the physiological and growth indexes, a mathematical model was established, and the optimized irrigation and fertilizer amounts of jujube in northern Xinjiang area were found to be 815 mm and 400 kg ha−1 (with N–P2O5–K2O proportioned at 2–1–1.5). The results that were obtained in this paper would provide theoretical reference to the sustainable development of jujube plantation using drip irrigation in the arid areas. Full article
(This article belongs to the Special Issue Data-Driven Methods for Agricultural Water Management)
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Open AccessReview Woody Plant Encroachment Impacts on Groundwater Recharge: A Review
Water 2018, 10(10), 1466; https://doi.org/10.3390/w10101466
Received: 1 September 2018 / Revised: 14 October 2018 / Accepted: 15 October 2018 / Published: 17 October 2018
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Abstract
Woody plant encroachment has profound impacts on the sustainable management of water resources in water-limited ecosystems. However, our understanding of the effects of this global phenomenon on groundwater recharge at local and regional scales is limited. Here, we reviewed studies related to (i)
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Woody plant encroachment has profound impacts on the sustainable management of water resources in water-limited ecosystems. However, our understanding of the effects of this global phenomenon on groundwater recharge at local and regional scales is limited. Here, we reviewed studies related to (i) recharge estimation methods; (ii) mechanisms by which woody plants impact groundwater recharge; (iii) impacts of woody plant on recharge across different soil and geology; (iv) hydrological repercussions of woody plant removal; and (v) research gaps and needs for groundwater studies. We identified six different methods: water balance, water table, isotopes, chloride mass balance, electrical geophysical imaging, and modeling were used to study the impact of woody encroachment on groundwater. Woody plant encroachment could alter soil infiltration rates, soil water storage, transpiration, interception, and subsurface pathways to affect groundwater recharge. The impact is highly variable, with the extent and the magnitude varying across the soil, substrate, plant cover, and topographic locations. Our review revealed mixed effects of woody plant removal on groundwater recharge. Studies of litter interception, root water uptake, soil moisture dynamics, and deep percolation along with the progression of woody plant encroachment are still limited, warranting further experimental studies focusing on groundwater recharge. Overall, information about woody plant encroachment impacts on groundwater resources across a range of scales is essential for long-range planning of water resources. Full article
(This article belongs to the Special Issue Ecohydrology of Woodlands and Savannas)
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Open AccessArticle Contrasting Responses among Aquatic Organism Groups to Changes in Geomorphic Complexity Along a Gradient of Stream Habitat Restoration: Implications for Restoration Planning and Assessment
Water 2018, 10(10), 1465; https://doi.org/10.3390/w10101465
Received: 27 August 2018 / Revised: 28 September 2018 / Accepted: 6 October 2018 / Published: 17 October 2018
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Abstract
Many stream restoration projects aim to increase geomorphic complexity, assuming that this increases habitat heterogeneity and, thus, biodiversity. However, empirical data supporting these linkages remain scant. Previous assessments of stream restoration suffer from incomplete quantification of habitat complexity, or a narrow focus on
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Many stream restoration projects aim to increase geomorphic complexity, assuming that this increases habitat heterogeneity and, thus, biodiversity. However, empirical data supporting these linkages remain scant. Previous assessments of stream restoration suffer from incomplete quantification of habitat complexity, or a narrow focus on only one organism group and/or one restoration measure, limiting learning. Based on a comprehensive quantification of geomorphic complexity in 20 stream reaches in northern Sweden, ranging from streams channelized for timber floating to restored and reference reaches, we investigated responses of macroinvertebrates, diatoms, and macrophytes to multiple geomorphic metrics. Sediment size heterogeneity, which was generally improved in restored sites, favored macroinvertebrate and diatom diversity and macroinvertebrate abundance. In contrast, macrophyte diversity responded to increased variation along the longitudinal stream profile (e.g., step-pools), which was not consistently improved by the restoration. Our analyses highlight the value of learning across multiple restoration projects, both in identifying which aspects of restoration have succeeded, and pinpointing other measures that might be targeted during adaptive management or future restoration. Given our results, a combination of restoration measures targeting not only sediment size heterogeneity, but also features such as step-pools and instream wood, is most likely to benefit benthic biota in streams. Full article
(This article belongs to the Special Issue Restoration of Biodiversity in Streams and Rivers)
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Open AccessFeature PaperArticle Optimal Energy Recovery from Water Distribution Systems Using Smart Operation Scheduling
Water 2018, 10(10), 1464; https://doi.org/10.3390/w10101464
Received: 21 August 2018 / Revised: 13 October 2018 / Accepted: 15 October 2018 / Published: 17 October 2018
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Abstract
Micro hydropower generators (micro turbines), are used to recover excess energy from hydraulic systems and these applications have important potential in renewable energy production. One of the most viable environments for the use of micro turbines is the water distribution network where, by
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Micro hydropower generators (micro turbines), are used to recover excess energy from hydraulic systems and these applications have important potential in renewable energy production. One of the most viable environments for the use of micro turbines is the water distribution network where, by design, there is always excess energy since minimum pressures are to be maintained throughout the system, and the system is designed to meet future water supply needs of a planning period. Under these circumstances, maintaining the target pressures is not an easy task due to the increasing complexity of the water distribution network to supply future demands. As a result, pressures at several locations of the network tend to be higher than the required minimum pressures. In this paper, we outline a methodology to recover this excess energy using smart operation management and the best placement of micro turbines in the system. In this approach, the best micro turbine locations and their operation schedule is determined to recover as much available excess energy as possible from the water distribution network while satisfying the current demand for water supply and pressure. Genetic algorithms (GAs) are used to obtain optimal solutions and a “smart seeding” approach is developed to improve the performance of the GA. The Dover Township pump-driven water distribution system in New Jersey, United States of America (USA) was selected as the study area to test the proposed methodology. This pump-driven network was also converted into a hypothetical gravity-driven network to observe the differences between the energy recovery potential of the pump-driven and gravity-driven systems. The performance of the energy recovery system was evaluated by calculating the equivalent number of average American homes that can be fed by the energy produced and the resulting carbon-dioxide emission reductions that may be achieved. The results show that this approach is an effective tool for applications in renewable energy production in water distribution systems for small towns such as Dover Township. It is expected that, for larger water distribution systems with high energy usage, the energy recovery potential will be much higher. Full article
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