Water — Open Access Journal

This study was conducted as part of the Joint Crediting Mechanism (JCM) of the Japanese Ministry of Economy, Trade and Industry, and the Ministry of the Environment project’s preparation in Vietnam. Samples were taken from hot and cold water supplies from guest rooms’ faucets in 12 hotels in Hanoi city, Vietnam, and 13 hotels in Japan for comparison. A simple water quality measurement and determination of Legionella was carried out. The results showed that residual effective chlorine—which guarantees bactericidal properties—was not detected in tap water supplied in hotel rooms in Vietnam, and nitrite (an indicator of water pollution) was detected in 40% of buildings. In the hotels in Japan, the prescribed residual chlorine concentration met the prescribed levels, and nitrite was not detected. Additionally, while there was no Legionella detected in the Japanese cases, it was detected in most of the Vietnamese hotels, which were found to manage the hot water storage tank at low temperatures of 40–50 °C. It was found that there were deficiencies in cold and hot water supply quality, and that there was no effective system in place for building operation maintenance and management. Full article

Given the scientific consensus that climate change is impacting biodiversity, estimates of future climate change effects on stream communities and assessments of potential biases are necessary. Here, we propose a simple technique to approximate changes in invertebrate and fish biomonitoring results. Taxa lists for 60 (invertebrate) and 52 (fish) sites were each modified by 10 multipliers as stepwise 5% or 10% changes in abundances to simulate potential climate-change severity, reflecting increasing climate change effects. These 10 multipliers were based on the stream zonation preference for invertebrates and the Fish Region Index (FRI) values for fish, both reflecting the longitudinal gradient present in river ecosystems. The original and modified taxa lists were analyzed using the standard assessment software for the particular group, followed by analysis of key biomonitoring metrics. For invertebrates, our simulations affected small good quality streams more often negatively while large poor mountain streams showed a tendency to improve. Forty percent of the invertebrate data sites showed a change in the final ecological assessment class when using the multipliers, with the poor quality sites changing more often. For fish, metric changes were variable, but the FRI ratio showed mostly positive responses, i.e., a shift in FRI towards downstream communities. The results are discussed as an example that facilitates the interpretation of potential climate-change effects with varying severity. Further, we discuss the simplified approach and implications for assessment from climate change induced range shifts. Full article

The sorption–desorption of recalcitrant pharmaceuticals in sand/soil columns can be used to infer performance of managed aquifer recharge. Removal of carbamazepine (CBZ) and diatrizoate (DTZ) from synthetic wastewater, containing 100 µg·L⁻¹ of each pharmaceuticals, was studied in recirculating sand columns amended with uncoated or methacrylic acid (MAA) coated magnetite nanoparticles. Removal of CBZ and DTZ in MAA-magnetite column (68.34% and 61.91%, respectively) was much higher than that with uncoated magnetite (53.47% and 50.26%, respectively). Rapid decrease of dissolved organic carbon concentrations across nanoparticle amended columns (between 42.28% and 50.08% on Day 1), followed by slow recuperation suggests adsorption–desorption dynamics and competition of dissolved organic matter for sorption sites. Core-level binding energy and charge analysis for Fe(2s) and O(1s) in X-ray photoelectron spectroscopy suggests involvement of physisorption process on the NP surfaces. Full article

Due to the high density of buildings and low quality of the drainage pipe network in the city, urban non‐point source pollution has become a serious problem encountered worldwide. This study investigated and analyzed the characteristics of non‐point source pollution in Baoding City. A simulation model for non‐point source pollution was developed based on the Stormwater Management Model (SWMM), and, the process of non‐point source pollution was simulated for Baoding City. The data was calibrated using data from two observed rainfall events (25.6 and 25.4 mm, the total rainfall on 31 July 2008 (07312008) was 25.6 mm, the total rainfall amount on 21 August 2008 (08212008) was 25.4 mm) and validated using data from an observed rainfall event (92.6 mm, the total rainfall on 08102008 was 92.6 mm) (Our monitoring data is limited by the lack of long‐term monitoring, but it can meet the requests of model calibration and validation basically). In order to analyze the effects of non‐point source pollution on Baiyangdian Lake, the characteristics and development trends of water pollution were determined using a one‐dimensional water quality model for Baoding City. The results showed that the pollutant loads for Pb, Zn, TN (Total Nitrogen), and TP (Total Phosphorus) accounted for about 30% of the total amount of pollutant load. Finally, applicable control measures for non‐point source pollution especially for Baoding were suggested, including urban rainwater and flood resources utilization and Best Management Practices (BMPs) for urban non‐point source pollution control. Full article

Construction in urban areas usually results in compacted soil, which restricts plant growth and infiltration. Nutrients may be lost in storm runoff water and sediment. The purpose of this study was to determine if existing lawns benefit from aeration and surface compost additions without the negative impact of nutrient loss in runoff. Four sets of lawns were compared, with or without compost plus aeration, as a paired comparison. Surface bulk density was significantly reduced in the treated lawns (1.32 versus 1.42 Mg·m⁻³). Visual evaluation of soil structure showed improvement in the treated lawns. Of fifteen measurement dates over four years, four dates showed significantly higher surface soil water contents in the treated lawns compared with the untreated lawns. When compared over time, three of the four treated lawns had significantly higher soil water content than the untreated lawns. Nutrient concentrations in rainfall simulator runoff were not significantly different between treated and control lawns, which showed that compost did not negatively impact water quality. Compost and aeration helped restore soil quality for urban soils of recent construction. Full article

Available water resources for agricultural irrigation have decreased worldwide in recent decades, prompting advances in water saving methods. In this study, soil water regime and water balance in a transplanted rice field with reduced irrigation (multiple shallow depth irrigations) in the Taihu Lake Basin of East China were observed and then evaluated using Hydrus-1D model during two consecutive growing seasons. During the 2008 season, irrigation water accounted for 48% of the total water input (TWI, 94.6 cm), but only 20% of TWI (120.4 cm) during the 2009 season. Due to heavy rainfalls during the wet 2009 season, surface runoff accounted for about 6.4% of the TWI, whereas during the much drier 2008 season with higher controlled irrigation inputs, no surface runoff occurred. Simulated evapotranspiration during the 2008 and 2009 seasons accounted for 67.4% and 54.9% of TWIs, respectively. Measured and simulated results indicate that water percolation (approximately 32.5% and 37.6% of TWIs during the 2008 and 2009 seasons, respectively) was the main path of water losses from the transplanted rice fields, suggesting that long and high standing water during the 2009 season increased water percolation. Water productivities evaluated from total irrigations and TWIs were 2.08 and 0.99 kg·m⁻³ during the 2008 season and 3.85 and 0.77 kg·m⁻³ during the 2009 season, respectively, and were 1.47 and 1.40 kg·m⁻³, respectively, when evaluated from modeled evapotranspiration fluxes. The cultivation method with multiple shallow depth irrigation efficiently used rainfall water and reduced the losses due to water percolation and surface runoff by stabilizing rice yields. Full article

Surface water storage is a key component of the terrestrial hydrological and biogeochemical cycles that also plays a major role in water resources management. In this study, surface water storage (SWS) variations are estimated at monthly time-scale over 15 years (1993–2007) using a hypsographic approach based on the combination of topographic information from Advance Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Hydrological Modeling and Analysis Platform (HyMAP)-based Global Digital Elevation Models (GDEM) and the Global Inundation Extent Multi-Satellite (GIEMS) product in the Ganges-Brahmaputra basin. The monthly variations of the surface water storage are in good accordance with precipitation from Global Precipitation Climatology Project (GPCP), river discharges at the outlet of the Ganges and the Brahmaputra, and terrestrial water storage (TWS) from the Gravity Recovery And Climate Experiment (GRACE), with correlations higher than 0.85. Surface water storage presents a strong seasonal signal (~496 km³ estimated by GIEMS/ASTER and ~378 km³ by GIEMS/HyMAPs), representing ~51% and ~41% respectively of the total water storage signal and it exhibits a large inter-annual variability with strong negative anomalies during the drought-like conditions of 1994 or strong positive anomalies such as in 1998. This new dataset of SWS is a new, highly valuable source of information for hydrological and climate modeling studies of the Ganges-Brahmaputra river basin. Full article

In this study, an integrated approach involving multiple standardized indicators and hydrological modeling (Soil and Water Assessment Tool, SWAT) was evaluated to reconstruct and characterize meteorological, agricultural and hydrological droughts in Upper Kafue River Basin of Zambia during 1984–2013. Standardized Precipitation Index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI) were used to identify meteorological droughts. Standardized Soil Moisture Index (SSI) was applied to characterize agricultural droughts and Standardized Runoff Index (SRI) was calculated to illustrate hydrological droughts. Input data for SRI and SSI computation was obtained from SWAT model which simulated daily and monthly runoff well with Nash–Sutcliffe efficiency (NSE) and coefficient of determination (R²) greater than 0.65. The results showed that: (1) all indices were able to detect temporal variability of major drought events in a humid subtropical basin in Southern Africa; (2) SWAT successfully simulated runoff and soil moisture although soil moisture requires further calibration to increase accuracy; (3) the average duration and intensity for meteorological droughts at three-month time scale were lower but frequencies were higher compared to agricultural and hydrological droughts at 3- and 12-month aggregates; and (4) drought events exhibited a negative trend as evaluated by Mann–Kendall on SPEI, indicating an increase in drought severity, and correlation analysis between SPEI and SRI revealed that SPEI at 9–15 months has a strong link with hydrological conditions. This study showed that a comprehensive assessment of droughts by integrating multiple variables provided a versatile tool for drought monitoring and mitigation. Full article

Poor drainage of urban storm water can lead to urban inundation which presents a risk to people and property. Previous research has presented various measures to prevent and reduce urban flooding and these measures can be classified into costly but effective structural measures, and economical but less effective non-structural measures. This study suggests a new approach to reduce urban flooding by combining structural and non-structural measures in a target watershed in Seoul, South Korea. Inlet design modification in a detention reservoir (Decentralized Reservoir, DR) is examined in conjunction with combined inlet/outlet management for the DR. Monitoring nodes used to control DR inlet/outlet operations are selected by locating the first flooding node, maximum flooding node and DR inlet node. This new approach demonstrates outstanding flood volume reduction for historical flooding events that occurred in Seoul during 2010 and 2011. Flood volumes during the 2010 event using the combined inlet/outlet operation in the DR were between 1656 m³ and 1815 m³ compared to a flood volume of 6617 m³ using current DR operation. Finally, the suggested operating level for the DR based on the best hydraulic section, system resilience index, and local regulations is 1.2 m. Full article

Water vapor transport (WVT) is an important element in drought development. In this study, we examined the geographical and vertical anomalies of WVT during severe summer and early fall drought processes and their occurrence, persistence and recovery phases in Southwest China (SWC) by using the method of standardized anomalies (SA) and composite analysis. The SA-based indices of WVT were built up to quantify composited anomalous WVT channels objectively. Essentially, we further explored the synchronous and lagged correlations between drought processes and these channels. Key points and limitations include: (1) Two drought-related WVT channels were geographically identified with composited SA below −0.2, based on the composite of severe drought processes. The Somali channel is characterized by zonally less-than-normal African-Asian continental WVT anomalies originating from Somalia, whereas the IndoChina-Peninsula channel represents meridionally less-than-normal WVT anomalies from the IndoChina-Peninsula; (2) Both geographical and vertical WVT anomalies were intensified and concentrated at the time of drought occurrence, and then weakened and became scattered at drought recovery; (3) Most drought-related WVT anomalies were distinguishable from those of wetter events; (4) The IndoChina-Peninsula channel performs better in correlations with these drought and wetter processes than the Somali channel. Therefore, dynamic and thermodynamic anomalies need to be investigated, which are important for exploring the drought mechanism. Full article

Studies using Drought Hazard Indices (DHIs) have been performed at various scales, but few studies associated DHIs of different drought types with climate change scenarios. To highlight the regional differences in droughts at meteorological, hydrological, and agricultural levels, we utilized historic and future DHIs derived from the Standardized Precipitation Index (SPI), Standardized Runoff Index (SRI), and Standardized Soil Water Index (SSWI), respectively. To calculate SPI, SRI, and SSWI, we used a calibrated Soil and Water Assessment Tool (SWAT) for the Karkheh River Basin (KRB) in Iran. Five bias-corrected Global Circulation Models (GCMs) under two Intergovernmental Panel on Climate Change (IPCC) scenarios projected future climate. For each drought type, we aggregated drought severity and occurrence probability rate of each index into a unique DHI. Five historic droughts were identified with different characteristics in each type. Future projections indicated a higher probability of severe and extreme drought intensities for all three types. The duration and frequency of droughts were predicted to decrease in precipitation-based SPI. However, due to the impact of rising temperature, the duration and frequency of SRI and SSWI were predicted to intensify. The DHI maps of KRB illustrated the highest agricultural drought exposures. Our analyses provide a comprehensive way to monitor multilevel droughts complementing the existing approaches. Full article

Extreme precipitation events have been extensively applied to the design of social infra structures. Thus, a method to more scientifically estimate the extreme event is required. This paper suggests a method to estimate the extreme precipitation in Korea using a regional climate model. First, several historical extreme events are identified and the most extreme event of Typhoon Rusa (2002) is selected. Second, the selected event is reconstructed through the Weather Research and Forecasting (WRF) model, one of the Regional Climate Models (RCMs). Third, the reconstructed event is maximized by adjusting initial and boundary conditions. Finally, the Probable Maximum Precipitation (PMP) is obtained. The WRF could successfully simulate the observed precipitation in terms of spatial and temporal distribution (R² = 0.81). The combination of the WRF Single-Moment (WSM 6-class graupel scheme (of microphysics), the Betts-Miller-Janjic scheme (of cumulus parameterization) and the Mellor-Yamada-Janjic Turbulent Kinetic Energy (TKE) scheme (of planetary boundary layer) was determined to be the best combination to reconstruct Typhoon Rusa. The estimated PMP (RCM_PMP) was compared with the existing PMP. The RCM_PMP was generally in good agreement with the PMP. The suggested methodology is expected to provide assessments of the existing PMP and to provide a new alternative for estimating PMP. Full article

An accurate budget of substance emissions is fundamental for protecting freshwater resources. In this context, the European Union asks all member states to report an emission inventory of substances for river basins. The river basin management system MoRE (Modeling of Regionalized Emissions) was developed as a flexible open-source instrument which is able to model pathway-specific emissions and river loads on a catchment scale. As the reporting tool for the Federal Republic of Germany, MoRE is used to model annual emissions of nutrients, heavy metals, micropollutants like polycyclic aromatic hydrocarbons (PAH), Bis(2-ethylhexyl)phthalate (DEHP), and certain pharmaceuticals. Observed loads at gauging stations are used to validate the calculated emissions. In addition to its balancing capabilities, MoRE can consider different variants of input data and quantification approaches, in order to improve the robustness of different modeling approaches and to evaluate the quality of different input data. No programming skills are required to set up and run the model. Due to its flexible modeling base, the effect of reduction measures can be assessed. Within strategic planning processes, this is relevant for the allocation of investments or the implementation of specific measures to reduce the overall pollutant emissions into surface water bodies and therefore to meet the requirements of water policy. Full article

The study presents a method which can be used to define real-time operation rules for gated spillways (named the K-Method). The K-Method is defined to improve the performance of the Volumetric Evaluation Method (VEM), by adapting it to the particular conditions of the basin, the reservoir, or the spillway. The VEM was proposed by the Spanish engineer Fernando Girón in 1988 and is largely used for the specification of dam management rules during floods in Spain. This method states that outflows are lower than or equal to antecedent inflows, outflows increase when inflows increase, and the higher the reservoir level, the higher the percentage of outflow increase. The K-Method was developed by modifying the VEM and by including a K parameter which affects the released flows. A Monte Carlo environment was developed to evaluate the method under a wide range of inflow conditions (100,000 hydrographs) and with return periods ranging from one to 10,000 years. The methodology was applied to the Talave reservoir, located in the South-East of Spain. The results show that K-values higher than one always reduce the maximum reservoir levels reached in the dam. For K-values ranging from one to ten, and for inflow hydrographs with return periods higher than 100 years, we found a decrease in the maximum levels and outflows, when compared to the VEM. Finally, by carrying out a dam risk analysis, a K-value of 5.25 reduced the expected annual damage by 8.4% compared to the VEM, which represents a lowering of 17.3% of the maximum possible reduction, determined by the application of an optimizer based on mixed integer linear programming (MILP method). Full article

The green revolution in the northwest region of Bangladesh over the past three decades has based on groundwater irrigation. For sustainable agricultural accretion, groundwater dynamics play a vital role in this region. In this study, the groundwater level dynamics have been analyzed with a model named “MAKESENS” and with geographical information systems (GIS). The study indicates that, in most of the wells, the water table (WT) depth and the rainfall intensity are declining slowly. The prediction of WT depth during the period of 2020, 2040, and 2060 indicate that, in some cases, the WT depth will approximately double by the year 2060, considering the present declining trend. This result suggests that, for the sustainable management of groundwater, necessary measures should be adopted to avoid or reduce the severe ecological, social, and economic impacts of groundwater mining. Moreover, crop diversification, conservation techniques, increasing irrigation efficiency, rainwater harvesting, etc. can be adopted to avoid groundwater declination and consequently to enhance the sustainable use of groundwater resources in the area. Full article

The Budyko equation has achieved iconic status in hydrology for its concise and accurate representation of the relationship between annual evapotranspiration and long-term-average water and energy balance at catchment scales. Accelerating anthropogenic land-use and climate change have sparked a renewed interest in predictive applications of the Budyko equation to analyze future scenarios important to water resource management. These applications, in turn, have inspired a number of attempts to derive mathematical models of the Budyko equation from a variety of specific assumptions about the original Budyko hypothesis. Here, we show that the Budyko equation and all extant models of it can be derived rigorously from a single mathematical assumption concerning the Budyko hypothesis. The implications of this fact for parametric models of the Budyko equation also are explored. Full article

The presence of heavy metals in water for human use or consumption represents a major risk to human health. It is therefore important to find materials to remove or minimise the concentration of these pollutants. The adsorption process for the removal of heavy metals is favoured by the use of low-cost materials that exhibit a porous structure and a high cation exchange capacity, such as zeolites and clays. On the other hand, chemical treatments, e.g., using acids and bases, can modify the properties of these materials, but more recently the application of surfactants has also shown to be successful for broadening their metal affinity and allowing the removal of diverse organic and inorganic pollutants from water. This paper reviews the application of modified zeolites and clays for the removal of heavy metals from water. Full article

Stormwater runoff monitoring was carried out from 2011 to 2015 to investigate the relationships between rainfall conditions (antecedent dry days (ADDs), rainfall intensity, depth and duration), and water quality parameters of stormwater from a paved road in Korea. Factor analysis suggested that the effect of rainfall conditions on the concentrations of selected pollutants varied depending on the pollutant. As total COD (total chemical oxygen demand) concentration increased, the level of heavy metals increased and resulted in a decrease of BOD₅ (biochemical oxygen demand) because of their toxicity. In addition, ADDs had a significant impact on the wash-off of solids from paved road. The predominant particles in stormwater were 30 μm and smaller, and increased in concentration as ADDs increased. Thus, the initial load of accumulated particles became a major factor in the wash-off process. The mass of particle-related pollutants was also subject to the effect of ADDs due to the affinity between pollutants and predominant particles (<30 μm). However, the effect of ADDs on the mass of organic matter and nitrogen was relatively weak. ADDs contributed to the decrease of some pollutants by photo-oxidation, volatilization and natural decay over dry days, as well as desorption from solids during rainfall. Full article

Aesthetic value is an important factor that should be considered in lake environments. However, there is a lack of research examining and undertaking investigation of the aesthetic value of multifunctional lake ecosystems. There are two major purposes for this study: (1) to define and investigate the important perceived attributes related to the aesthetic value of multifunctional lakes using a video-questionnaire method and (2) to provide some suggestions for the further development of a visual quality index facilitating decision making in management and policies. An enhanced visual quality method was used in this study to record the conditions of the multifunctional lakes in each location in the study area. The findings of the study defined water color and clarity, percentage of water hyacinth, types of debris, percentage of debris, and facilities and land values as the important attributes related to aesthetic value in multifunctional lakes. In summary, the perceived attributes in the visual ecology criteria indicated more significant relationships with the functional morphology criteria than the financial profitability criteria. The results showed that the video-questionnaire method used in this study is efficient, easy to use, and understandable in terms of identifying and measuring aesthetic value in relation to perceptions of perceived attributes. Full article