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Identifying the influence of heavy precipitation and ecological water replenishment (EWR) on groundwater resources is essential for the management of groundwater resources and for risk prevention. This study innovatively developed a groundwater resource analysis and prediction model integrated with the water level fluctuation method, correlation analysis, and machine learning method under the influence of heavy precipitation and EWR. The results of the water level fluctuation method showed that compared with January 1, 2021, the groundwater resources of the study area increased to 4.46 × 108 m3 on August 28. Compared with the small flow of EWR, heavy precipitation was the main contributor to the rise in the groundwater level. Correlation analysis found that elevation, specific yield, and permeability coefficient show positive correlations with groundwater resource recharge. Machine learning results showed that among the water level prediction models of 35 monitoring wells, extreme gradient boosting (XGB) and random forest (RF) performed best in 30 wells and 5 wells, respectively. The increase in groundwater storage predicted deviation from the actual value by only 0.6 × 107 m3 (prediction bias of 1.3%), indicating that the model prediction performance was well under the condition of heavy precipitation. This study can help to better understand the changing trends of groundwater resources under the influence of heavy precipitation and EWR.

In this paper, a fuzzy mathematical programming method is introduced on the basis of the interval two-stage stochastic programming (ITSP) optimisation model for the wetland ecological water replenishment scheme in Boluo Lake National Nature Reserve. The minimum ecological water supply is taken as the objective function, and the lake bubble water diversion capacity, lake bubble water supply capacity, water diversion sequence, ecological service value, and minimum capacity of the wetland water supply are taken as constraints. The ecological water replenishment schemes of five lakes in the Boluo Lake National Nature Reserve are optimised at the levels of low flow years, normal flow years, and high flow years, and an optimised model for the wetland ecological water replenishment scheme in Boluo Lake National Nature Reserve based on the interval fuzzy two-stage stochastic programming (IFTSP) method is constructed. The model fully considers the waste of water resources and the protection of migratory bird habitat and makes rational allocation of water resources to make full use of flood resources. The IFTSP model proposed herein fully considers the fuzzy and uncertain characteristics of the planning area in the lake bubble area of Boluo Lake National Nature Reserve and improves the decision-making efficiency of decision-makers by providing technical support for smooth implementation of the ecological water replenishment project in nature reserves. The model can also be used as a theoretical guide for ecological recharge projects in other regions of the world.

Wetlands as an important ecosystem type have been damaged in recent years and restoration of wetland ecosystem functions through ecological water replenishment is one of the important ways. The present study involved the construction of a novel ecological water replenishment model for Jilin Momoge National Nature Reserve (JMNNR) using the interval two-stage stochastic programming (ITSP) method. Breaking down traditional economic models that often sacrifice environmental benefits, the model aims to replenish the ecological water in JMNNR, allocate the ecological water resources scientifically, restore the wetland function of the reserve, improve the functional area of the reserve, enhance the net carbon sequestration capacity of the reserve, and complete the reconstruction of the ecosystem, while considering the ecological service value (ESV) of the reserve to achieve a joint increase in the ecological and economic benefits. The ITSP model constructed in the present study overcame the limitation that the original project recommendation was a single recommended value, and the results are presented in the form of intervals to improve flexibility in decision making to allow the individuals responsible for under-taking decisions to bring focused adjustments according to the actual decision-making conditions and increase the selectivity of the decision-making scheme. The present report discusses the construction of an ITSP model for the ecological water replenishment of JMNNR in an attempt to effectively improve both economic benefits and ecosystem restoration of the reserve, achieve the reconstruction of the JMNNR ecosystem, and provide a selective decision space for the key decision-makers to formulate and optimize the project operation and the management plan. The use of the ITSP model as a pre-procedural basis for the implementation of the project and the simulation of the effects of the implementation of the project can effectively avoid the decision limitations that exist when carrying out the project directly. The ITSP model constructed in this paper can also be used as a theoretical guide for water replenishment projects in different areas of the world, and the model parameters can be reasonably adjusted to achieve better results when used according to the actual local conditions.

There has been notable depletion of groundwater resources globally in recent decades. Groundwater can be conserved by ecological water replenishment. An understanding of the factors influencing the effect of ecological water replenishment on groundwater recharge is of great significance for water resource management. This study used the improved water table fluctuation and water equilibrium method and Spearman correlation analysis in R to evaluate the effect of ecological water replenishment on groundwater recharge. Furthermore, the correlations between groundwater recharge and topography, hydrogeological conditions, and meteorological factors were analyzed. Groundwater storage in the plain area of the Yongding River (Beijing section) increased by 2.17 × 108 m3 in 2020, equating to an increase in the regional groundwater level of 73.6% (increase of 0.1–9.1 m, arithmetic mean of 2.3 m). The main sources of groundwater recharge are ecological water replenishment and precipitation. The ecological water replenishment first recharged the Ordovician limestone aquifer in the gorge area, following which karst water overflowed through the fault zone to resupply the Quaternary groundwater in the plain area, resulting in a lag in the groundwater recharge effect. Groundwater recharge was positively correlated with ground elevation and aquifer permeability and negatively correlated with the thickness of Quaternary strata and the distance between the recharge point and Yongdinghe fault zone. This study can help to better explain the effect and impact of ecological water replenishment on groundwater resource recharge and its implications for improving ecological water replenishment projects.

Ecological water replenishment is considered to be an important project to adjust river ecosystems with water shortages and degradation, and its impact on the water quality of the target river section deserves attention. By investigating the characteristics of inorganic ions and organic components of the Beijing section of the Yongding River (YDR) from upstream to downstream, the sources of inorganic ions and dissolved organic matter (DOM) during an ecological water replenishment event were analysed and discussed. This study illustrated the hydrochemical response to different supplemental water sources in three sections of the YDR (mountain gorge section (MGS), urban plain section (UPS), and suburb plain section (SPS)). The results showed that the total dissolved solids (TDS) and ion concentrations were significantly different (p 0.001) in the three river sections due to different supplemental water sources. The highest concentration of TDS was found in the UPS (870.92 mg/L) replenished by reclaimed water, while the lowest concentration of TDS was found in the SPS (306.95 mg/L) replenished by the water of the South-to-North Water Diversion Project (SNWD). Despite the differences in the water sources of replenishment, the optical parameters of DOM and fluorescent components showed similar protein-like dominated endogenous source characteristics in the three river sections of the YDR, which was due to the influence of reservoir water (MGS and SPS) and reclaimed water (UPS). Our study emphasizes the importance of understanding the impact of different water sources on the water replenishment process, which provides a scientific reference for the management of ecological water replenishment.

Diversion rivers are important water and biological connection channels, which provide valuable ecological services. However, diversion rivers are degraded owing to the construction and unreasonable operation of large-scale water conservancy projects. Quantifying and guaranteeing the ecological flow of diversion rivers is necessary to sustain the riverine ecosystems. Due to the lack of methods to verify the rationality of the existing hydrological series length for ecological flow calculation by hydrological methods, a Monte Carlo-length of record (MC-LOR) algorithm was proposed to analyze the accuracy level of the existing hydrological series. Taking the Dongjing River (DJR) in the lower Han River as an example, the result shows that the 15-year hydrological series can meet the accuracy level of 5/90 and 10/95. The flow changes and hydrological relationships between the Qianjiang hydrological station (QJS) and the Tianguan River (TGR) under the influence of the Middle Route of South-to-North Water Transfer (MSNW) project and the Yangtze–Han Water Diversion (YHWD) project were analyzed. It is found that the flow variation of QJS is large and shows a downward trend while TGR displays a significant upward trend through the M-K trend test. And the flow of QJS is drier and less than the water replenishment of TGR in the non-flood season after the operation of the MSNW project. This paper established an ecological flow threshold calculation method based on kernel density curves and quantiles. Compared with the minimum average monthly flow (MAMF) method, the monthly minimum ecological runoff (MMR) method, improved Q90 method, Tennant method, Tessmann method, distribution flow method (DFM), the method proposed in this paper can reduce the influence of extreme flow events and is suitable for the diversion river. Finally, the ecological water replenishment demands of TGR to meet the ecological flow target of DJR under different flow conditions in the Han River were analyzed by Bayesian network (BN) models. The results show that the minimum water requirement thresholds of DJR are 31.3m3/s and 15.85m3/s, 55.35m3/s and 30.85m3/s when the flows of Han River are 3/s and 654 ~ 770m3/s in non-flood season and 3/s and 875 ~ 1210m3/s in flood season, respectively. This research provides references for the ecological stability and sustainable development of diversion rivers.

In the present paper, an optimization model of the ecological water replenishment quantity of Boluo Lake wetland was constructed for ecological water replenishment in the Boluo Lake National Nature Reserve based on the interval two-stage stochastic programming (ITSP) method, which scientifically allocates the ecological water resources and enhances the utilization of flood resources in order to meet the minimum ecological water replenishment quantity requirement to meet the local economic and social water demand, to restore the wetland function of the reserve, and to improve the ecological environment. In addition, it considers the ecological service value of the reserve in order to achieve a shared increase in the ecological and economic benefits. The optimization model of the ecological water replenishment of Boluo Lake wetland considered the minimum ecological water replenishment as the objective function, while the water diversion capacity, water supply capacity, water diversion sequence, functional area, and ecological service value of the Lake bubble were utilized as constraints in order to restore the ecosystem function of the Boluo Lake National Nature Reserve. The results from the model revealed that the amount of ecological water replenishment was significantly reduced after optimization simulation, with the maximum reduction range in the ecological water replenishment being −100.00% and −74.58%. In addition, the total amount of flood diversion was significantly increased, and the flood resources could be fully utilized. Moreover, the recovery effect on the lake and pond functional areas was significant and compared much better to that prior to the ecological water replenishment, which was up to 2300.00% and 1987.59%. The ecological service value also increased significantly, and the rate of this increase was as high as 23.90% and 21.58%. In the present study, an optimization model was constructed for the ecological water replenishment of the Boluo Lake wetland supplement project based on the interval two-stage stochastic programming method, which would achieve the entire scope of ecological and economic benefits of the ecological water replenishment project by realizing the ecological system reconstruction and providing a feasible and reliable plan to the decision-makers.

Ecological water replenishment (EWR) via interbasin water transfer projects has been regarded as a critical solution to reducing the risk of lake shrinkage and wetland degradation. The hydrological conditions of EWR water sources do not change synchronously, which may have an impact on the transferable water. Based on the GAMLSS model and the multivariate Copula model, this work presents a research approach for EWR via interbasin water transfer projects that can capture the non-stationarity of the runoff series and the frequency of dryness–wetness encounters, as well as speculates on various scenarios throughout the project operation phase. We present a case study on the Baiyangdian Lake, acting as the largest freshwater wetland in North China, which has suffered from severe degradation during the past decades and deserves thorough ecological restoration. The GAMLSS model was used to examine the non-stationarity characteristics of EWR water sources including the Danjiangkou Reservoir (DJK), the Huayuankou reach of the Yellow River (HYK), and upstream reservoirs (UR). The multivariate Copula model was implemented to evaluate the synchronous–asynchronous characteristics for hydrological probabilities for the multiple water sources. Results show that 1) significant non-stationarity has been detected for all water sources. Particularly, a significant decreasing trend has been found in UR and HYK. 2) The non-stationary model with time as the explanatory variable is more suitable for the runoff series of DJK, HYK, and UR. Under the non-stationary framework, the wet–dry classification of runoff series is completely changed. 3) Whether the bivariate or trivariate combination types, the asynchronous probability among the three water resources is over 0.6 except DJK-HYK, which indicates the complementary relationship. Multiple water resources are necessary for EWR. What is more, during a dry year of UR, the conditional probability that both DJK and HYK are in a dry year is 0.234. To alleviate the problem of not having enough water, some additional water resources and an acceptable EWR plan are required.

The article proposes a method for calculating parameters of feed water replenishment in an alkaline electrolyzer, taking into account the given alkali concentrations and the actual electrolyte consumption. The analysis of the electrolyte specific electrical conductivity under electrolysis process is carried out. Recommendations are given for increasing the water electrolysis process efficiency by reducing energy consumption when ensuring the optimal specific electrical electrolyte conductivity at a variable alkali concentration. One of the possible algorithms is presented for calculating electrolyzer parameters to ensure its specified operational characteristics under process of hydrogen and oxygen generation.

A photovoltaic thermal (PVT) system is a renewable cogeneration system that produces low temperature heat and electricity simultaneously from solar radiation. In water based PVT systems, as the thermal load is served, storage tank is replenished immediately with cold makeup water. However, it is possible to determine an optimal water replenishment profile to optimize the overall configuration of PVT system. In this paper, effects of water replenishment on PVT system sizing are studied. At first, the problem is modeled as a mixed integer non-linear programming problem to analyze the impact of water replenishment on PVT system sizing. Subsequently, the design space approach is used to analyze the significance of water replenishment strategy on the PVT system configuration. Finally, based on analytical derivation, an approximate water replenishment profile is determined and its practical implementation strategies are discussed. Applicability of the proposed methodologies is demonstrated through sizing PVT systems for residential as well as industrial hot water usage patterns. Significant reductions in both collector area (10% for residential example and 7% for industrial example) and storage volume (66% for residential example and 23% for industrial example) are observed. (C) 2016 Elsevier Ltd. All rights reserved.

Due to its independent control and directly easy operation, ecological water replenishment (EWR) has been an important measure for restoring river ecosystems. However, the positive and negative contribution of the EWR activities to aquifer system are not fully understood under the combined influences of climate change and human activities across time scales. A refined groundwater flow model integrating an open channel flow at daily time scales is developed in a part of Northern China Plain to reproduce the dynamic process of groundwater level changes. After model calibration with groundwater level and runoff data, the changes of simulated groundwater level and river runoff have the Nash-Sutcliffe efficiency coefficient of 0.98 and 0.60, respectively. Results clearly demonstrate that the impulse response of aquifer recovery to runoff in three centralized EWRs. By using with and without EWR method, the simulated maximum contribution of EWR near river to aquifer recovery may be over 70 %. Scenario analysis method considering different precipitation, groundwater exploitation reduction and EWR activities are applied to evaluate the total quantities of aquifer recovery. The prediction of nine-year EWR activities under multiple scenarios shows that the increased groundwater level generally varies from 4.08 to 8.57 m, and the contribution of EWR accounts for 7.88 %-36.59 %. It is also noticed that 14 out of the 18 informal landfill sites will face potential groundwater pollution risks, indicating the negative influences of long-term EWR activities. This study can provide a method for quantifying the influences and contribution of EWR on aquifer recovery and can be referred to as a guideline for EWR evaluation with similar hydrogeological conditions.

Assessing the bacteria pathogens in the lakes with reclaimed water as major influents are important for public health. This study investigated microbial communities of five landscape lakes replenished by reclaimed water, then analyzed driven factors and identified health effects of bacterial pathogens. 16S rRNA gene sequence analysis demonstrated that Proteobacteria, Actinobacteria, Cyanobacteria, Firmicutes, and Verrucomicrobia were the most dominant phyla in five landscape lakes. The microbial community diversities were higher in June and July than that in other months. Temperature, total nitrogen and phosphorus were the main drivers of the dominant microbial from the Redundancy analysis (RDA) results. Various potential bacterial pathogens were identified, including Pseudomonas, GKS98_freshwater_group, Sporosarcina, Pseudochrobactrum, Streptomyces and Bacillus, etc, some of which are easily infectious to human. The microbial network analysis showed that some potential pathogens were nodes that had significant health effects. The work provides a basis for understanding the microbial community dynamics and safety issues for health effects in landscape lakes replenished by reclaimed water.

Ecological water replenishment (EWR) has been increasingly applied to the restoration and maintenance of wetland hydrological conditions across China since the beginning of the 21st century. However, little is known about whether EWR projects help protect and/or restore wetland ecohydrology. As one of the earliest and longest-running EWR projects in China, water has been released from the Nenjiang River into the Zhalong wetland since 2001. It is important to examine the ecohydrological effects of this EWR project. In this study, long time series remote sensing data were used to extract the water area, inundation frequency, and normalized difference vegetation index (NDVI) to explore how eco-hydrological conditions changed during the pre- (1984–2000) and post-EWR (2001–2018) periods in the Zhalong wetland. Results show that the inundation area decreased due to the reduced surface water inflow during the pre-EWR period. Similarly, monthly vegetation NDVI in the growing season generally exhibited a decreasing and an increasing trend during the pre- and post-EWR periods, respectively. In the post-EWR period, NDVI increased by 19%, 73%, 45%, 28%, 13% for the months of May through September, respectively. Due to EWR, vegetation growth in areas with low inundation frequency was better than in areas with high inundation frequency. We found that the EWR project, runoff, and precipitation contributed 25%, 11%, and 64% to changes in the NDVI, respectively, and 46%, 37%, and 17% to changes in inundation area, respectively. These results indicate that the EWR project has improved hydrological conditions in the Zhalong wetland. For further maximum benefits of EWR in the Zhalong wetlands, we suggest that implementing similar eco-hydrological projects in the future should focus on flood pulse management to increase the inundation area, improve hydrological connectivity, and create new habitats.

Ecological water replenishment is an effective approach to the wetlands suffering water shortage. However, optimizing the replenishment is a tough problem, considering local flow pattern, water exchange and environmental crisis. Therefore, determining the inlet position and the flow rate of water diversion remains an interesting and important topic. This study developed an applicable and reliable method to identify the preferable inlet location and inflow rates of the transferred water, which considers the influence of the factors on environmental risks in receiving water bodies based on numerical results using the lattice Boltzmann method (LBM) in both Lagrangian and Eulerian frameworks. An environmental risk assessment system with comprehensive utilization of water age was established. The Water Transfer Project for the Baiyangdian Lake from the Yellow River is a representative and well-known water replenishment event in China, which served as a case study. The results show that under the static and NNE wind conditions, the north open inlet is a suitable inlet position, while the south one is preferable under the SSW wind condition. Considering the environmental risk of the water transfer, it indicates that higher inflow rate would bring less environmental risk generally and the optimal inflow rate is 20 m 3 / s , regardless of the wind conditions and the inlet position. The methods aforementioned played a vital role in optimizing the inlet position of water delivery and selecting the optimal plan of the recharge rate. It could provide a useful reference for ecological restoration and a guarantee for sustainable development of wetlands.

One of the tasks in modern approach of the water resources management is improving environment health by the way of the river restoration. On the urban area it is impossible to provide full river restoration, but at the same time it is possible to create the environment close to natural. In our work on the example of the river Uzh located inside the city provides the assessment of the restoring possibility of the part of the floodplain by water replenishment of the old riverbed during the vegetation season. Flood control dyke construction interrupted the connection between old riverbed and river and as a result floodplain lake became muddy, silted up and lost its attractive form. To assess the possibility of the floodplain lake replenishment, the simulation of some scenarios were carried out: natural condition, water replenishment during flood, pumping water, raising water level in the river Uzh near the lake. The connection of the lake and the old riverbed with the river will improve slightly the storage capacity of the lake and allows to provide the depth of up to 1.0 m in the lake during flood, but the water will be absent in the old riverbed during the dry season. Hydraulic calculation showed that replenishment during spring floods and pumping water were not possible due to high hydraulic conductivity of the gravel and pebble soils. The old riverbed replenishment is possible by raising water level in the river Uzh, which will ensure the free water flow into the lake and into the old riverbed during the dry season.

The stable isotopic study of the mechanism of runoff replenishment in the Qinghai-Tibet Plateau is a time-consuming and complicated process requiring complex monitoring data and scientific evaluation methods. Based on the data of water stable isotopes (18O and 2H) in the Naqu River basin, the present paper developed a framework of the variable fuzzy evaluation model (VFEM) to provide a method to classify stable isotopes and generalize the source identification of water replenishment by rainfall or snowmelt in the Naqu River basin. The grade eigenvalues of tributaries were ranked from low to high as follows: 1, 1.005, 1.089, 1.151, 1.264, 1.455 and 2.624. Three sets of tributaries were distinguished. The grade eigenvalues of the Najinqu, Bazongqu, Mumuqu, Chengqu and Gongqu Rivers were small, indicating that these tributaries were strongly supplemented by precipitation and snowmelt, the grade eigenvalue of the Zongqingqu River was in the medium range (1.455), the third group included the Mugequ River with a high status value (2.624). This study mainly highlighted the combination of the classification of stable isotopes and plots of &delta, 2H vs. &delta, 18O in the source identification of water replenishment, which will be helpful for studying runoff replenishment and the evolution mechanism in the Qinghai-Tibet Plateau.

Due to changes in the snowmelt timing and the potential shift towards less snowfall and more rainfall, infiltration patterns into the soil will increasingly be altered in a warming climate. Mixing and transport processes of water in the unsaturated topsoil layer regulate the subsurface transport and retention of solutes and contaminants, as well as the distribution of plant available water. Recent advances in soil isotope ecohydrology indicate that in some ecosystems, water in macropores largely bypasses soil matrix and rapidly percolates into the groundwater. Here we combine tracer experiments and geophysical surveys to explore soil water mixing in non-stratified till soil in the Pallas catchment located in sub-arctic conditions in Finnish Lapland. A 5x20 m plot at the Kenttärova hilltop was sprinkled with deuterated water (d2H 88‰) for two days (totally 200 mm at average intensity of 6.7 mm/h), until surface water ponding was observed on substantial share of the plot. Soil moisture dynamic were monitored by a network of soil moisture sensors and manual soil probe measurements. Soil water was sampled hourly with suction cup lysimeters at three (5 cm, 30 cm, 60 cm) depths and pan lysimeter at 35 cm depth in two soil profiles on the irrigation plot. Groundwater was sampled hourly, while xylem samples from spruce and birch trees in the plot were collected on each day of the experiment and on a weekly basis during the following month. Ground penetrating radar (GPR) survey and soil coring with window sampler down to 1 m depth were completed four times over the course of the experiment, and additional set of soil cores were taken two weeks after the experiment to inspect how natural precipitation events have infiltrated into the deuterium enriched zone. We investigate the mechanisms of soil matrix water replenishment by answering the following questions: i) Can all soil matrix water be displaced during high volume events and when does newly introduced soil matrix water become available to the plants?; ii) What is the extent of soil water mixing at different depths?; and iii) What is the effect of increased moisture content and groundwater table rise on soil water mixing? Due to paucity of field data sets and inability of most hydrological models to accurately simulate soil freezing and thawing effects, ecohydrologic partitioning has been barely studied in Northern regions with seasonal snow cover. We present a novel field data set that focuses on soil matrix water replenishment in glaciated till soil at sub-arctic conditions. Results support our understanding of ecohydrological processes in northern environments where hydrological cycle is dominated by intense infiltration events as it occurs during snowmelt.

Due to the intensified influence of human activities, Yongding river presents a sharp decrease in water quantity and a trend of continuous deterioration of water environment, and the ecological environment is seriously damaged. Under this background, Yongding river ecological reconstruction project needs to be carried out urgently, and ecological water replenishment mode needs to be determined urgently. In order to explore the influence of multi-water source ecological replenishment mode on the evolution of river water quality and riverbank percolation water quality, this study conducted a simulation experiment to explore the influence of flow rate, temperature and soil percolation on reclaimed water replenishment water quality. The results show that the increase of flow velocity is beneficial to the degradation of pollutants. Compared with high temperature, the degradation capacity of pollutants at low temperature is significantly better than that at high temperature, indicating that low temperature is beneficial to the improvement of reclaimed water quality to some extent. Some water quality indexes of riverbank leachate improved to some extent, but the water passing through the soil was slightly eutrophication due to the aggregation and adsorption of river bottom sediments. The final results show that the velocity of flow has the greatest influence on the quality index of regenerated water.

The sesame crop has stood out due to the high nutritional content of its seeds, in addition to being able to be cultivated in the tropical and subtropical regions such as Northeast Brazil. Thus, it is necessary to identify the physiological, biochemical and productive changes related to the tolerance to stress. Objective of this study was to evaluate the physiological, biochemical and productive aspects of sesame genotypes as a function of different rates of water replenishment. The experiment was carried out at the Embrapa Cotton Experimental Unit, located in the municipality of Barbalha-CE, Brazil, under field conditions. The experiment was carried out in a randomized complete block design, with treatments in a factorial scheme (4 × 6), corresponding to four irrigation depths (40, 70, 100 and 130% ETo) and six sesame genotypes (G1 = T3-EGSGO3; G2 = T7-EGSGO7; G3 = T5-EGSGO5; G4 = T2-EGSGO2; G5 = T6-EGSGO6; G6 = T4-EGSG04), with three replicates. Data corresponding to the following variables were collected: leaf area, photosynthetic pigments, relative water content in leaf, electrolyte leakage, catalase, peroxidase, yield and oil content. The genotypes did not differ statistically and there were differences in the variables between the water replacement rates. Increments in growth and, consequently, in production, enzymatic activity, oil content and maximum production potential were observed with water depths between 75 and 90% ETo. Contents of chlorophyll a and b, total chlorophyll and carotenoids, were increased with the application of 80% ETo. RESUMO O cultivo de gergelim vem se destacando devido ao alto teor nutricional de suas sementes, além de poder ser cultivado nas regiões tropicais e subtropicais como o Nordeste brasileiro, sendo necessária a identificação das alterações fisiológicas, bioquímicas e produtivas relacionadas com a tolerância ao estresse. Objetivou-se avaliar o comportamento fisiológico, bioquímico e produtivo de genótipos de gergelim em função de diferentes taxas de reposições hídricas. O experimento foi realizado na Unidade Experimental da Embrapa Algodão, localizada no Município de Barbalha, CE, sob condições de campo. O delineamento adotado foi em blocos casualizados, com tratamentos em esquema fatorial (4 × 6), correspondendo a quatro lâminas de irrigação (40; 70; 100 e 130% da ETo) e seis genótipos de gergelim (G1 = T3-EGSGO3; G2 = T7-EGSGO7; G3 = T5-EGSGO5; G4 = T2-EGSGO2; G5 = T6-EGSGO6; G6 = T4-EGSG04) com três repetições. Foram coletados dados correspondentes às variáveis: área foliar, pigmentos fotossintéticos, teor de relativo de água na folha, extravasamento de eletrólitos, catalase, peroxidase, produtividade e teor de óleo. Os genótipos de gergelim não diferiram estatisticamente, no entanto houve diferenças entre as reposições hídricas com um aumento no crescimento e consequentemente, na produção, atividade enzimática, teor de óleo e o potencial máximo da produção com a aplicação de lâminas entre 75 e 90% da ETo. O conteúdo de clorofila a e b, total e carotenoides foram incrementados com a aplicação de 80% da ETo.

The partitioning of rainfall by plant canopies into throughfall (TF) and stemflow (SF) affects the process of rainfall infiltration into the soil as well as the ecological functions of soil water. A change in land use from croplands to orchards inevitably influences the preexisting rainfall partitioning and soil water replenishment processes. However, few studies have focused on the differences in TF and SF and their effects on soil water replenishment after converting croplands into apple orchards. Thus, the objectives of this study were to quantify the differences in TF and SF between maize (Zea mays L.) and apple trees (Malus domestica, cv. Fuji), clarify their influencing factors, and compare the efficiency of soil water replenishment by rainfall from June to September as well as the soil water content and storage in each hydrological year of the study. Under the same rainfall conditions, the rainfall was distributed differently due to the presence of the maize and apple tree canopies. The sum of the TF and SF in the maize field (129.1 mm and 167.6 mm) was lower than that in the apple orchard (250.4 mm and 354.2 mm) in 2017 and 2018, respectively; the TF amount in the apple orchard was on average 3.4 times that in the maize field, while the SF amount in the maize field was on average 12.9 times that in the apple orchard. The TF percentage ranged from 0 to 76.9 % and 0 to 97.9 % for the maize field and the apple orchard, respectively, while the SF percentage ranged from 0 to 37.5 % and 0 to 3.3 %. The soil water input sources for the maize field were TF and SF, while the input source for the apple orchard was mainly TF. TF and SF production increased linearly with rainfall in the apple orchard. The rainfall amount was identified as the variable with the greatest influence on rainfall partitioning among the rainfall factors considered. An increasing leaf area index resulted in decreasing relative TF but increasing relative SF for maize and decreasing relative TF and SF for apple trees. The mean efficiency of the replenishment of soil water by rainfall in the maize field (30.8 % and 37.4 % in 2017 and 2018, respectively) was slightly lower than that in the apple orchard (34.4 % and 41.0 %). This study provides insight into water cycle analyses aimed at understanding rainfall partitioning and the soil water environment within croplands converted into apple orchards on the Loess Plateau and in other, similar regions.

Hengshui Lake Wetland is the only national wetland and bird nature reserve in the North China Plain. It plays an important role in maintaining the species diversity and ecological balance. In recent years, due to industrial and agricultural production, infrastructure and ecological environment construction and other reasons, the infiltration, runoff, evapotranspiration and other water balance elements was changed, which reduced runoff into the lake. In order to ease the tense water resources situation in the region, Hengshui Lake is replenished each year by Yellow River water. Although Diversion Yellow River Wetland has made direct water supply protection, but also affected the ecology and environment of Hengshui Lake wetlands. In order to understand how artificial water diversion can affect the ecological environment of natural lakes, this paper analyzes the effects of artificial water storage on the water quality of the lake by using the measured data of water samples in the lake. The results showed that the water level of Hengshui Lake showed an upward trend after the diversion from the Yellow River. Comprehensive pollution index showed a downward trend, but Hengshui Lake wetlands are still slightly polluted. Diversion of Yellow River diversion into the lake of the ecological health of Hengshui also caused some impact.

Large-scale afforestation has seriously aggravated the consumption of soil water and caused soil desiccation and even the dry soil layers, which has been restricting the survival and sustainability of vegetation in semi-arid areas. How to solve soil water deficit reasonably is an important practical problem we are facing. Here, a field experiment of the decayed roots with different times on soil water infiltration processed was conducted in planted forestland by a double-ring infiltration instrument, to determine the contribution of decayed tree roots on soil water infiltration process and replenishment. Results showed that the decayed process of tree roots in forestland could significantly reduce root density (RD) and increase the relative porosity improved by the roots (RPIR) (P

There are numerous wetland rehabilitation projects worldwide, but their efficiency is seldom assessed comprehensively. Oxbow lakes are wetlands of particular sensitivity. Within a large-scale floodplain rehabilitation project in Hungary, the Old Drava Programme, water replenishment was first carried out for the Cun-Szaporca oxbow lakes, a key area in the project. To assess its sustainability, the entire hydrological system has been monitored. From the data of hydrological monitoring (infiltration, soil moisture, groundwater/lakewater interaction) it is claimed that water replenishment involves significant losses through seepage (4.1 and 1.46 mm d−1) and evaporation (3.01 and 1.44 mm d−1) in the studied pre-intervention and replenishment periods, resp. Infiltration alone is insufficient to replenish groundwater and raise oxbow lake levels. In the critical summer half-year evaporation is intensive in the neighbouring agricultural fields. Groundwater table dynamics are controlled by hyporheic and groundwater flow. Major impact on the water balance of the oxbow lakes is exerted by the regime of the Drava River. A deepened lakebed is recommended to ensure more effective water retention in the oxbow lake. From the local study conclusions are drawn for the feasibility of rehabilitation at floodplain scale and in areas with similar hydromorphological conditions.

Zika virus (ZIKV), a positive-strand RNA virus belonging to the Flavivirus genus, has become an urgent public health concern since recent outbreaks worldwide. Its genome replication is facilitated by the viral NS3 protein bearing helicase function. The NS3 helicase uses energy derived from adenosine triphosphate (ATP) hydrolysis to unwind RNA duplexed regions. Structural studies of the flavivirus NS3 helicases have suggested a conserved mechanism of ATP hydrolysis. However, the process of the reactant water replenishment, a key part of the hydrolysis cycle, remains elusive. Here, we report two high-resolution crystal structures of ZIKV NS3 helicase in complex with adenosine diphosphate (ADP) and Mn

A reservoir usually functions as multi-objectives. Different objective has various requirement in water volume and temporals process due to the fact that some objectives require different constant base flow in different months and some objectives demand ephemeral flood pulse. How to balance reservoir functioning and water allocation of multiple targets has become increasingly significant at present. In the past, the multi-objectives operation was usually designed based on water quantity balance, neglecting the coupling with the hydrodynamic process. Sometimes the coupling is so important for some ecological factors and the neglecting may result in failure to meet the hydraulic requirements of the downstream ecological environment. By coupling the hydrologic and hydrodynamic methods, an integrated reservoir model for multiple-objectives optimal operation was presented including water balance model, one-dimensional unsteady flow model, two-dimensional depth-averaged model and ecological baseflow model. The different process demands include water allocation at the dam site, unsteady flow process at different sections downstream the dam site. Taking a reservoir in northern China as an example, the minimum change of the hydrological process in the river mouth section was set as the objective function for the optimal operation. Regarding the demand for aquatic organisms, the low and high baseflow schemes were suggested by the comprehensive use of different ecological flow methods (the Tennant method, the flow duration curve method and the wetted perimeter method). According to the ecological flooding during the wetland water supplement, the Wetland Water Replenishment Model was applied to calculate the replenishment process under different flood cases. The Lake Water Replenishment Model was used for flow scheduling of the downstream lake. Regarding the wet years, the objective functions at the river mouth section were 16.0% with the low baseflow scheme and 15.5% with the high baseflow scheme, whereas for the dry years, it is 18.2% with the low baseflow scheme and 15.5% with the high baseflow scheme. Comparison showed that the high baseflow scheme was optimal for the reservoir operation. The result could provide a reference for decision-makers in reservoir scheduling design. It shows that the coupling of hydraulic and hydrological methods could provide a more reliable basis for reservoir optimal operation.

The ecological water replenishment (EWR) of Yongding River has been an important project implemented in response to the Development of an Ecological Civilization policy in China since 2016. A reasonable amount of EWR requires a systematic understanding of the relationship among the surface water, groundwater, ecology and economy. However, studying surface water-groundwater interactions still remains an important issue. Thus, a coupled model integrating a Muskingum method-based open channel flow model and machine learning-based groundwater model is developed to describe the dynamic changes in streamflow and groundwater level in response to the EWR of Yongding River. The model is calibrated using observed streamflow data as well as groundwater level data on a daily scale for the spring EWR in 2020. The simulated results match well with the observed data and suggest that significant groundwater level increases occur only around the main channel of Yongding River. Fifteen scenarios under different EWR schemes are set to obtain reasonable streamflow during EWR, and then the responses of streamflow and groundwater level changes are simulated. Reasonable streamflow at the Guanting Reservoir need to be above 65 m3/s to ensure the streamflow can pass through Beijing and significant groundwater level recoveries of 170 million m3 through EWR. The developed models can improve the understanding of the interaction between surface water and groundwater and provide a quick assessment of the factors influencing the different EWR schemes and thus aid in effective EWR project management.

With rapid urbanization, there will be more conflict between human systems and the river ecological system, and therefore, ecological operations, practices and research must involve the ecological water replenishment of entire river basins with new modeling tools. In this study, based on a water resource allocation and simulation model (WAS), we establish an ecological flow-oriented water resource allocation and simulation framework (E-WAS) by comprehensively considering both ecological flow constraints and ecological flow targets. To control multiple types of water sources and dynamically allocate water resources to replenish ecological water in the river, virtual reservoirs and ecological units are added to the model network. With new water balance equations for virtual reservoirs and ecological units, the E-WAS can simulate the ecological replenishment process in a river basin and can provide a recommended water replenishment scheme that considers optimization principles. The E-WAS was applied in the Pingshan River Basin, Shenzhen, China. Fourteen ecological units and 38 water supply nodes are considered in the model. A water replenishment scheme that used water from 6 reservoirs and reclaimed water from 5 water sewage plants was selected. This scheme significantly increased the satisfactory degree of ecological water demand and efficiently supported the formulation of a control scheme for the water environment of a basin. The E-WAS framework is similar to model plug-ins but helps to avoid the large workload that is required for model redevelopment and can expand the functions of core models relatively quickly.

Lakes in arid regions are ecologically valuable yet highly fragile due to intense evaporation. To provide an extra water supply for maintaining water balance in lakes, the Ecological Replenishment Water Program (ERWP) in northwest China has significantly changed the hydrological and hydrochemical conditions for these lakes. Descriptive statistics and water and mass balances, together with hydrogeochemical modeling were used in this study to gain an understanding of the impacts of water replenishment (irrigation and drainage water) on evolution for Shahu Lake. A virtual sample was introduced in NETPATH hydrogeochemical modeling to compute the net chemical reactions in the lake water. Variations in TDS indicated that the lake evolved to be saline during 2004–2012 (stage I) and then tended to be fresh during 2013–2014 (stage II). Results highlighted that groundwater outflow and chemical reactions were the overriding factors controlling chemical evolution in the lake system, which greatly depend on the replenishment activities. The salinity reduction from the virtual samples to the final samples were attributed to the precipitation of calcite and dolomite, dissolution of gypsum, Na-K and Na-Ca exchange, and the CO2 degassing in the lake system at an annual scale of 0.11 g/L in stage I and 0.15 g/L in stage II. The quality of replenishment water was as important as quantity for rehabilitating lakes, as it significantly determines the occurrence of chemical reactions in lake water. Findings from this paper can provide insight into the evolution of arid lakes in response to replenishment activities and can help contribute to better management of a valuable and fragile resource.

As water resources have been developed, the input of water into wetlands by rivers has decreased. Thus, these wetland ecosystems are seriously threatened. The upstream reservoir must be operated in a manner that provides downstream wetlands with their ecological water requirement. Here, a method for analysing the effects of artificial water replenishment from reservoirs on wetlands is established. A hydrodynamic mathematical model was coupled by a one-dimensional longitudinal and depth-averaged two-dimensional hydrodynamic model to simulate the water replenishment process in wetlands. The results indicate that the overflow of floodwaters into wetlands may not occur if insufficient reservoir water is discharged. In contrast, if too much water is discharged, excess water will reach the wetland and cause a water shortage upstream. Furthermore, the results showed that there is a quantitative relationship between the area of water in a wetland and the flow discharged by the upstream reservoir. This analytical method provides direct data that can be used to ensure that wetlands receive enough water from reservoirs to maintain their ecological functions and to avoid wasting the water resources of upstream reservoirs.

Wetland ecological water replenishment becomes necessary in most developing countries. A holistic water replenishment scheme considering both wetland ecosystem services and irrigation requirement is needed for river water reallocation. A framework was developed in this study to calculate wetland ecological water demand (WD), river water supply capacity (RSC) and the benefit of wetland ecological water replenishment and crop irrigation with consideration of the seasonal effects. The Xianghai wetland and the Taoerhe irrigation district (TID) were considered as the study area to investigate various wetland ecological water replenishment schemes (WRS). The results showed that the WRS, considering both wetland function and agricultural irrigation, has the highest overall benefit compared to the schemes with a single focus (either wetland or irrigation). In addition, the WRS design must consider the seasonal effect because of seasonal variation of rainfall, crop growth, and wetland plants and animals&rsquo, growth. The WRS design with consideration of seasonal effect not only increased the total value of river basin from $74.83 million to $104.02 million but also balanced the benefit between TID and wetland while meeting wetland WD. This study offers a decision-making framework of developing a holistic WRS considering benefits from multiple water users and seasonal variation.

To understand the relationships among rainfall–infiltration–evaporation–replenishment in mobile dunes in the semi-arid areas of China, we used the Container of Water Distribution (100 × 100 × 120 cm3) to examine rainfall infiltration, soil water redistribution, and soil surface evaporation under natural and simulated rainfall conditions. The results showed that infiltration depth was linearly related to rainfall amount and intensity. Rainfall amounts larger than 13.4 mm, could replenish soil water at 60 cm depth after redistribution, while with rainfalls larger than 39.8 mm, infiltration depth could exceed 120 cm. Rainfall amounts larger than 50 mm produced saturated soil water at 120 cm depth, and replenishment amount accounted for 40.4 % of the total amount of rainfall. Soil surface evaporation exhibited a relatively minor change with increases in rainfall when rainfall was larger than 11.8 mm. The amount of evaporation and soil water content were significantly correlated at 0–60 cm soil depth, but not below. These results suggest that the maximum effective depth of evaporation is 60 cm below the ground surface, and that rainfall of 13.4 mm is a threshold distinguishing effective from ineffective rainfall in the mobile dunes of the Horqin Sandy Land.

Successful wetland restoration is frequently constrained by the absence of persistent attention to the whole remedial process. The paper put forward a holistic method to restore the lacustrine wetland ecosystem. Yilong Lake wetland, one of the nine largest lakes of the Yun-Gui Plateau in China, was used as a case study. A modified (Pressure-State-Response) PSR model was presented to establish a comprehensive indicator system and to explain the ecological sustainability. Ecosystem sustainability and water quality were set as the general restoration target and the constraint restoration target, respectively, that makes the restoration goals not only contains the whole ecosystem but also the key individual parts. Two restoration goals (high and low) were set based on the cluster analysis of the historical data from 1952 to 2006. Different restoration levels give the decision makers and managers flexible options to restore the ecosystem based on the actual demand and practical capacity. Three restoration scenarios about the water replenishment and pollutant reduction were set to improve the ecological condition. The results showed that the integrated restoration measures according to water quantity and water quality can feasibly achieve the prescribed restoration levels. The paper gives the decision makers a holistic method to solve problems in lacustrine wetland restoration process.