ALBERT

Beschreibung: 〈p〉Publication date: Available online 27 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Advances in Water Resources〈/p〉 〈p〉Author(s): Mohamed Ali Ben Alaya, Camille Ternynck, Sophie Dabo-Niang, Fateh Chebana, Taha B.M.J. Ouarda〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Change point detection methods have an important role in many hydrological and hydraulic studies of river basins. These methods are very useful to characterize changes in hydrological regimes and can, therefore, lead to better understanding changes in extreme flows behavior. Flood events are generally characterized by a finite number of characteristics that may not include the entire information available in a discharge time series. The aim of the current work is to present a new approach to detect changes in flood events based on a functional data analysis framework. The use of the functional approach allows taking into account the whole information contained in the discharge time series of flood events. The presented methodology is illustrated on a flood analysis case study, from the province of Quebec, Canada. Obtained results using the proposed approach are consistent with those obtained using a traditional change point method, and demonstrate the capability of the functional framework to simultaneously consider several flood features and, therefore, presenting a comprehensive way for a better exploitation of the information contained in a discharge time series.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 583〈/p〉 〈p〉Author(s): Matan Ben Yona, Alon Rimmer, Eylon Shamir, Iggy Litaor〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The hydrologic responses of two similar in size watersheds in the Lake Kinneret basin are examined: Karstic Hermon watershed and basaltic Meshushim watershed. The streamflow properties at these watersheds are different in their surface flow to baseflow ratio, runoff coefficients and response to extreme rainfall events. The HYdrological Model for Karst Environment (HYMKE) model, developed to simulate daily flow in karst formation, was modified to address the basaltic formation at the Meshushim watershed. Water fluxes simulations were used to compare the hydrologic processes between the watersheds. The twice-higher annual precipitation in the Hermon watershed, generates annual streamflow that is five times more than in the Meshushim. This amplification of the rainfall-streamflow ratio between the watersheds is because larger fraction of the rainfall is lost to evapotranspiration at the basaltic Meshushim watershed and larger portion of the rainfall percolates to the karstic aquifer through preferential flow and appear as baseflow at the Hermon watershed. During large rainfall events when soil water content is near saturation, lower rainfall amount over the Meshushim watershed generates larger peak flow than the Hermon watershed. In both watersheds, surface flow was generated only when the soil water content is at or near saturation conditions. The streamflow dependency on soil water content, suggests high sensitivity of streamflow generation to the intra-annual variability of precipitation. Understanding the hydrologic response of the different sources of Lake Kinneret improves the ability to forecast its inflow.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 583〈/p〉 〈p〉Author(s): Igor Paz, Ioulia Tchiguirinskaia, Daniel Schertzer〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Precipitation risk and water management is a key challenge for densely populated urban areas. Applications derived from high spatio-temporal resolution observation of precipitations are to make our cities more weather-ready. Finer resolution data available from dual polarised X-band radar measurements enhance engineering tools as used for urban planning policies as well as protection (mitigation/adaptation) strategies to tackle climate-change related weather events. For decades engineering tools have been developed to work conveniently either with very local rain gauge networks, or with mainly C-band radars that have gradually been set up for space-time remote sensing of precipitation. Most of the time, the C-band radars continue to be calibrated by the existing rain gauge networks. Inhomogeneous distributions of these networks lead to only a partial information on the rainfall fields. Here we show that the statistics of measured rainfall is strongly biased by the fractality of the measuring networks and that this fractality needs to be properly taken into account to retrieve the original properties of the rainfall fields, in spite of the radar data calibration. In this work, we use the semi-distributed hydrological modelling over the Bièvre catchment to generate a virtual rain gauges’ network. And, firstly, performing a fractal analysis of this network distribution, we demonstrate that the semi-distributed hydrological models statistically reduce the distributed (weather radar) rainfall fields into rainfall measured by a much scarcer network of virtual rain gauges. Then, with the help of the Intersection Theorem and multifractal theory, we statistically compare the virtual rain gauges’ data with the rainfall data measured by the dual-polarimetric X-band radar operated at Ecole des Ponts with a spatial resolution of 250 m, providing pre-factors that indicate the need of a proper re-normalisation of rain gauge rainfall data when comparing (or calibrating) with radar data and the possible counter productivity of this conditioning.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 23 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology〈/p〉 〈p〉Author(s): Wei Chen, Xia Zhao, Paraskevas Tsangaratos, Himan Shahabi, Ioanna Ilia, Weifeng Xue, Xiaojing Wang, Baharin Bin Ahmad〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The main goal of the study was to estimate the efficiency and predictive ability of a series of tree-based ensemble methods in groundwater spring potential mapping. The study introduces a novel hybrid integration approach based on J48 Decision Trees (J48), AdaBoost (AB), Bagging (Bag), RandomSubSpace (RS), Dagging (Dag) and Rotation Forest (RF) algorithms for constructing a groundwater spring potential map. The performance of the ensemble models were evaluated at the Wuqi County in Shaanxi Province, China. At first, a groundwater spring inventory map with 235 groundwater springs was constructed. The groundwater spring database was randomly divided into a training (70% of the total number of groundwater springs) and validating subset (remaining 30%). Secondly, sixteen groundwater spring related variables were selected and analyzed, such as elevation, slope, aspect, planform and profile curvature, curvature, topographic wetness index, stream transport and stream power indexes, distance from river network, lithology, soil and landuse cover, normalized difference vegetation index, mean annual rainfall and distance from road network. The contribution of each groundwater spring related variable so as to identify the most predictive was based on the correlation attribute evaluation method. The predictive performance of each model was evaluated by estimating the area under the receiver operating characteristic (ROC) curve (AUC) and several statistical indexes (accuracy, sensitivity, specificity). The outcomes revealed that all models had a good predictive performance, having AUC values greater than 0.74. Specifically, RF-J48 model appeared with the highest prediction capability (AUC = 0.797), followed by the AB-J48 model (0.793), the Bag-J48 (0.768), the RS-J48 (0.766) and the Dag-J48 (0.748), respectively. The study highlights that the proposed ensemble methodology is efficient and highly accurate appropriate for groundwater spring potential mapping.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: March 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 582〈/p〉 〈p〉Author(s): Yinjun Zhao, Lan Zeng, Yongping Wei, Junming Liu, Jianming Deng, Qucheng Deng, Kai Tong, Jiaxu Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The impact of human activities on river systems has reached a state in which they can no longer be considered to be controlled only by natural processes of the Earth but also by anthropogenic forces in many regions of world. However, most approaches for assessing the impact still consider human activities to be an external influence in the study of feedback mechanisms between human activities and river systems, and they are usually complicated and specialized. This paper aims to develop an indicator system that includes the artificial water surface ratio (〈em〉AWSR〈/em〉), artificial water surface density ratio (〈em〉AWSDR〈/em〉), disruption of longitudinal connectivity ratio (〈em〉DLCR〈/em〉), artificial river ratio (〈em〉ARR〈/em〉), sinuosity of artificial cutoff (〈em〉SAC〈/em〉), channelization ratio (〈em〉CR〈/em〉), artificial levee ratio (〈em〉ALR〈/em〉), road along river ratio (〈em〉RARR〈/em〉), artificial sediment transport ratio (〈em〉ASTR〈/em〉) and the integrated river structure impact index (〈em〉IRSII〈/em〉) to quantitatively assess the impact of human activities on river structure by comparing natural and anthropogenic forces in a river system. The Nanliu River basin under the dramatic impact of human activities was selected to validate the indicator system. The case results showed the Nanliu River has become an anthropogenic river according to its high 〈em〉IRSII〈/em〉 value (greater than 0.49). The artificial water surface area and artificial sediment discharge were 2.96 (〈em〉AWSR〈/em〉 = 2.96) and 2.51 (〈em〉ASTR = 2.51〈/em〉) times of the outcome of natural process. The river was dramatically blocked by human-made buildings (〈em〉DLCR = 68.63)〈/em〉 and artificial channel accounts for 54.23% of total length of natural river (〈em〉ARR = 0.54〈/em〉). Within the river basin, upper and lower sub-basins in areas with a higher economic level were more affected by human activities. Future management of the Nanliu River basin should focus on restoration of river connectivity, sand mining and irrigation issues. Unlike most previous assessment methods, the approach developed in this study is simple and readily comprehensible by the public and decision makers, cost-effective for long-term monitoring and not subject to the reference condition.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: February 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Advances in Water Resources, Volume 136〈/p〉 〈p〉Author(s): 〈/p〉

Beschreibung: 〈p〉Publication date: Available online 23 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology〈/p〉 〈p〉Author(s): Chen Chen, Limin Zhang, Te Xiao, Jian He〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Ice-soil mixture landslide dams formed frequently in the Tibetan Plateau in response to global warming, which pose great threats to both upstream and downstream areas due to inundation and lake bursting. On 17 October 2018, a large landslide, induced by an ice-avalanche at the Sedongpu Basin of the Yarlung Tsangpo, blocked the main course of the river near Gyalha. The barrier lake level rose quickly and the dam was overtopped naturally at 13:30 on 19 October 2018, generating a dam-breaching flood with a peak flow rate of 32,000 m〈sup〉3〈/sup〉/s. This paper presents a comprehensive study of the disaster chain of landslide-barrier lake-dam breaching-river flooding in the Yarlung Tsangpo Grand Canyon, detailed geological and hydrological characteristics of the study region, rapid prediction of the dam breaching hydrograph using an erosion-based numerical model, and analysis of the flood routing in a 460 km canyon reach along the Yarlung Tsangpo. The simulated peak discharge at the dam site is over 30,000 m〈sup〉3〈/sup〉/s and the corresponding dam-breaching and flood routing hydrographs agree well with the observations. Two additional scenarios with larger inflow rates are also considered. Results show that with a larger inflow into the barrier lake, the erosion of the dam body becomes more rapid. When the inflow rate is increased by six times, the peak dam-breaching discharge can be doubled. The study serves as basis to manage the flood risks due to landslide dam bursting on the Yarlung Tsangpo or similar rivers.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 583〈/p〉 〈p〉Author(s): Jing Yang, Zhongbo Yu, Peng Yi, Shaun K. Frape, Meng Gong, Yuting Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Understanding the interaction between groundwater and surface water is of great significance to the rational development and utilization of water resources and the protection of ecological environment. Here we present a combination of several methods (radon balance method, EC conservation method and flow balance method) for evaluating the hydraulic exchange of groundwater and surface water in a small watershed of Kui river and Yunlong lake. The exchange fluxes of Kui river, Yunlong lake and groundwater were estimated by one-dimensional steady state model and box model. The results indicate that the lake water is mainly recharged by groundwater from the surrounding mountains and the lake renewal time is approximately 26 days. Meanwhile, multiple transformations occur between groundwater and river water, and river water leakage is dominant. The existence of several tributaries complicates the hydraulic exchange, and groundwater discharge is also evident. Furthermore, the advantages and disadvantages of these three methods were analyzed. This study successfully demonstrated that radon and EC as tracers can be used to estimate the exchange flux between groundwater and surface water, particularly in areas lacking conventional hydrological data. Combining these three methods, the hydraulic exchange between groundwater and surface water can be evaluated more effectively. The analysis of hydraulic exchange is also crucial for Xuzhou area where water resources are extraordinary scarce and polluted.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 583〈/p〉 〈p〉Author(s): John E. Solder, Bryant Jurgens, Paul E. Stackelberg, Christopher L. Shope〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Covering a large portion of the northern conterminous United States (1.87 × 10〈sup〉6〈/sup〉 km〈sup〉2〈/sup〉), the glacial aquifer serves as the primary water supply for 30 million public and domestic water users. Mean groundwater age, groundwater age distribution, and susceptibility to land surface contamination, using a new metric (Susceptibility Index; SI) based on the full age distribution and less prone to bias than estimated mean age, is reported for 168 public and domestic wells across the aquifer. Comparison of groundwater age metrics between well networks of varying spatial scale suggest an extensive sample network of equally spaced, long screened interval wells can be used to characterize aquifer wide groundwater age. Estimated mean age ranges from 1 to 50,000 years and, according to the composite age distribution, approximately 63 percent of all sampled water recharged after 1950 (i.e., modern) and 18 percent of the sampled water was recharged greater than 10,000 years ago. The later finding strongly suggests a connection between the glacial aquifer and underlying bedrock aquifers. Statistical analysis of glacial aquifer hydrogeology and age metrics show groundwater ages are young (less than few 100 years) and more susceptible to land surface contamination (larger SI) in unconfined and shallow portions of the aquifer. Old groundwater (greater than 1,000 years) is more often associated with thicker sequences of fine grain sediments and/or shallow bedrock. Calculated SI is shown to be more strongly related to the number of land surface contaminants detected than mean age or fraction modern. Statistical analysis of SI and hydrogeology indicates SI is largely dictated by well depth and confinement. This study demonstrates how sample network design can be used to characterize groundwater age of large aquifers with a limited number of samples and how interpretation of environmental tracers can be used to improve conceptual models of groundwater aquifers and identify groundwater susceptible to contamination.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 583〈/p〉 〈p〉Author(s): Xichao Gao, Ming Guo, Zhiyong Yang, Qian Zhu, Zhi Xu, Kai Gao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The relationship between extreme precipitation and the corresponding temperature is of great importance for predicting precipitation extremes in the future, given the rapid increase of global warming. This study investigates the relationship between extreme precipitation and the corresponding daily mean temperature over mainland China based on the China Meteorological Assimilation Driving Datasets for the Soil and Water Assessment Tool (CMADS). The relationship between extreme precipitation and daily maximum temperature before rainfall as well as that between relative humidity and daily mean temperature is investigated. The results show that (1) Among the patterns of the relationship between extreme precipitation and corresponding daily mean temperature, the peak pattern is dominant over mainland China, accounting for 95.80% of all the patterns; (2) a scaling of extreme precipitation with daily mean temperature greater than that represented by the C–C scaling is observed in most parts of China; (3) the peak-point extreme precipitation decreases from the southeast to the northwest of China, whereas the peak-point temperature ranges from 15 °C to 25 °C; (4) for most regions of China, the decreases in the relative humidity and the cooling effect of heavy extreme precipitation and its synoptic system contribute to the peak or negative pattern of the relationship between extreme precipitation and the corresponding daily mean temperature; and (5) compared with the cooling effect, the decrease of relative humidity is the first-order reason for the peak or negative pattern of the relationship between extreme precipitation and the corresponding daily mean temperature.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 25 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology〈/p〉 〈p〉Author(s): Zening Wu, Yanxia Shen, Huiliang Wang, Meimei Wu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Expected increases in intensity and frequency of rainfall extremes due to climate change, and increased paving and loss of water storage space in urban areas is making cities more vulnerable to pluvial flooding. It is a crucial step towards risk mitigation and adaptation planning to evaluate and predict flood disaster risk. In this study, a model coupling ontology and Bayesian Network that can capture the potential relationships between different factors influencing flood disaster and has capable of quantifying uncertainty and utilizing both data and observations was proposed. Based on the proposed model, the flood disaster risk in Zhengzhou City was assessed, which was validated by comparing with actual historical flood records. And the sensitivity analysis was carried out based on this model to determine that which factors would affect the disaster most. The results show that 72.3% of the study area was characterized by very-high to moderate flood disaster risk, which was mainly located in the central and eastern regions. The sensitivity analysis show that the rainfall duration is the most impactful factor, and the factors related to disaster-formative environment have low effect. The results revealed quite good agreement between the predicted flood disaster risk with actual flood records, which can be useful to assist flood mitigation and management. The model proposed in this study offers the Zhengzhou City and flood researches around the world, an effective way for evaluating flood disaster risk to manage uncertainty in water availability under climate change.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0022169420300561-ga1.jpg" width="402" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 24 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Advances in Water Resources〈/p〉 〈p〉Author(s): Scott K. Hansen〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Continuous-time random walk (CTRW) models of non-Fickian solute transport are defined by a temporal pdf and three parameters: a velocity-like constant, a dispersion-like constant and a “time constant”. Presently, to identify a model, all are jointly calibrated against solute breakthrough data. We show that without loss of generality the time constant can be set to unity and velocity-like and dispersion-like CTRW parameters can be set equal to well-defined classical counterparts, and thus physically pre-constrained. Thus only one entity, the pdf, requires empirical fitting during model calibration, rather than four. Our assertions are backed by numerical analysis.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 583〈/p〉 〈p〉Author(s): Shanshan Yao, Xiangzeng Wang, Qingwang Yuan, Zixi Guo, Fanhua Zeng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Multi-linear analytical models are of high computational convenience to simulate the fluid production out of low-permeability unconventional (tight and shale) reservoirs stimulated with multifractured horizontal wells (MFHWs). But multi-linear models cannot accurately describe the flow behavior in such reservoirs since the fluid flow around hydraulic fracture tips is not linear flow. This creates barriers for the multi-linear models to consider pressure/stress-dependent fracture and reservoir characteristics. In addition, multi-linear models in the literature cannot consider or fully consider heterogeneity conditions including the reservoir heterogeneity and well completion heterogeneity.〈/p〉 〈p〉In this study, a composite model is developed to model the fluid flow in unconventional reservoirs with MFHWs under various heterogeneity conditions. In the composite model, the reservoir is divided into sub-systems and each sub-system is further divided into flow regions. The fluid flow in one flow region can be simply linear, radial or source/sink flow. The composite model considers the pressure/rate distribution characteristics beyond fracture tips with fast calculations. The composite model is applicable to one or combinations of the following three heterogeneous conditions-fractured horizontal wells with heterogeneous completions, reservoir heterogeneity around the horizontal well and reservoir heterogeneity around a hydraulic fracture. The model’s applicability in heterogeneous reservoirs is demonstrated by the comparison with the trilinear-flow model, five-region model and numerical solutions. In this study solutions of the composite model are utilized to analyze two sets of production data from fractured horizontal wells in heterogeneous conditions.〈/p〉 〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: March 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Advances in Water Resources, Volume 137〈/p〉 〈p〉Author(s): Z.M. Wilmott, C.J.W. Breward, S.J. Chapman〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Experimental evidence shows that decreasing the salinity of the injection water during the oil recovery process can lead to an increase in the amount of oil recovered. While the ion-exchange reactions which cause this effect are well understood in an industrial setting, there is a limited understanding of how to quantitatively describe the macroscale low salinity effect in terms of the microscale mechanisms. In this paper, we derive a dynamic network model for the salinity-dependent two-phase flow of oil and water through a porous medium in which the salinity of the water affects the thickness of the thin water layer separating the oil phase from the solid surface through the multicomponent ionic exchange mechanism, which results in a salinity-dependent slip condition on the effective oil-solid interface. We solve the network model numerically for a drainage stage followed by waterflood stage on a 30 × 30 network with random pore and throat radii distributions, and present results averaged over multiple simulations. Low-salinity waterflooding is compared with high-salinity waterflooding in both secondary and tertiary mode. Our model is able to reproduce the low salinity effect observed experimentally, in which the amount of oil produced increases as the salinity of the injection brine decreases.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 583〈/p〉 〈p〉Author(s): Zehua Li, Xiaogang Shi, Qiuhong Tang, Yongqiang Zhang, Huilin Gao, Xicai Pan, Stephen J. Déry, Ping Zhou〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Glacier retreat and runoff increases in the last few decades characterize conditions in the Kumalak River Basin, which is a headwater basin of the Tarim River with a catchment area of 12,800 km〈sup〉2〈/sup〉. To address the scientific question of whether, and to what extent, the observed runoff increase can be attributed to enhanced glacier melt and/or increased precipitation, a glacier evolution scheme and precipitation-runoff model are developed. Using the glacio-hydrological model, we find that both glacier cover area and glacier mass in the study area have decreased from 1971 to 2010. On average, the contribution to total runoff from rainfall, glacier melt and snowmelt are 60.6%, 28.2% and 11.2%, respectively. Despite covering only 21.3% of the basin area, glacier areas contributed 43.3% (including rainfall, snowmelt and glacier melt) to the total runoff from our model estimates. Furthermore, as primary causes of increased runoff in response to the warmer and wetter climate over the period 1971–2010, contribution from increases in rainfall and glacier melt are 56.7% and 50.6%, respectively. In comparison to rainfall and glacier melt, snowmelt has a minor influence on runoff increase, accounting for −7.3%. The research has important implications for water resources development in this arid region and for some similar river basins in which glacial melt forms an important part of the hydrological cycle.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: March 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 582〈/p〉 〈p〉Author(s): Shen Qu, Guangcai Wang, Zheming Shi, Pengpeng Zhou, Qingyu Xu, Zejun Zhu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Characterizing the mining induced temporal changes of hydraulic properties of the overburden aquifer is significant for groundwater resource protection. Conventional hydrogeological methods (e.g. hydraulic test, physical model test and numerical simulation) of determining hydraulic properties of the overburden aquifer cannot quantitatively analyze the temporal changes of the hydraulic properties induced by mining disturbances. This paper demonstrates a quantitative determination for the temporal changes of parameters (compressibility, porosity and specific storage) in the overburden aquifer influenced by the mining processes, based on in-situ continuous measurements of groundwater level that was affected by earth tide, atmospheric loading and mining disturbances. The results showed that, when working face reached a certain distance (127 m from borehole J6 in this study), those parameters (compressibility, porosity and specific storage) of overburden aquifer began to show gradual decrease, with approximately up to two order of magnitudes. After the working face passed by the observation borehole J6, those properties of overburden aquifer recovered in about 80 days, which might reflect the characteristic of elastic deformation of the aquifer. Those findings of the mining induced parameters’ temporal changes could improve our understanding of the mining effects on aquifer system and could be meaningful in groundwater resource protection.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 583〈/p〉 〈p〉Author(s): Chao Zhuang, Zhifang Zhou, Walter A. Illman, Zhi Dou, Jinguo Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Extensometers provide long-term records of deformation over a depth interval of interest. An overconsolidated aquitard usually undergoes elastic deformation if the hydraulic head within adjacent aquifers remains higher than the preconsolidation head within the aquitard. The vertical hydraulic conductivity 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si10.svg"〉〈mrow〉〈mfenced close=")" open="("〉〈mrow〉〈msub〉〈mi〉K〈/mi〉〈mi〉v〈/mi〉〈/msub〉〈/mrow〉〈/mfenced〉〈/mrow〉〈/math〉 and elastic skeletal specific storage 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si11.svg"〉〈mrow〉〈mfenced close=")" open="("〉〈mrow〉〈msub〉〈mi〉S〈/mi〉〈mrow〉〈mi mathvariant="italic"〉ske〈/mi〉〈/mrow〉〈/msub〉〈/mrow〉〈/mfenced〉〈/mrow〉〈/math〉 are two critical parameters that control the deformation behavior of an overconsolidated aquitard, and they could be interpreted from valuable extensometer data. An analytical solution for the elastic aquitard deformation caused by periodic hydraulic head variations (PHHV) within adjacent aquifers is derived using the separation of variables method based on Euler’s formula. The phase difference in PHHV between adjacent aquifers is found to reduce the amplitude of periodic aquitard deformation. Meanwhile, the phase difference is found to cause no influence on the growth pattern of the phase shift, which is between the periodic aquitard deformation and PHHV, versus the period. A new parameter estimation method is further proposed to interpret aquitard 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si12.svg"〉〈mrow〉〈msub〉〈mi〉K〈/mi〉〈mi〉v〈/mi〉〈/msub〉〈/mrow〉〈/math〉 and 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si13.svg"〉〈mrow〉〈msub〉〈mi〉S〈/mi〉〈mrow〉〈mi mathvariant="italic"〉ske〈/mi〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉 from periodic aquitard deformation data. This new method yields robust 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si12.svg"〉〈mrow〉〈msub〉〈mi〉K〈/mi〉〈mi〉v〈/mi〉〈/msub〉〈/mrow〉〈/math〉 and 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si13.svg"〉〈mrow〉〈msub〉〈mi〉S〈/mi〉〈mrow〉〈mi mathvariant="italic"〉ske〈/mi〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉 estimates of a moderately thick aquitard, whose deformation history has been recorded by an extensometer, located in Shanghai, China. The field study confirms that the phase difference in PHHV between the aquifers adjacent to the overconsolidated aquitard of interest cannot be ignored.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: April 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 583〈/p〉 〈p〉Author(s): Salini Sasidharan, Scott A. Bradford, Jiří Šimůnek, Stephen R. Kraemer〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Drywells are widely used as managed aquifer recharge devices to capture stormwater runoff and recharge groundwater, but little research has examined the role of subsurface heterogeneity in hydraulic properties on drywell recharge efficiency. Numerical experiments were therefore conducted on a 2D‐axisymmetric domain using the HYDRUS (2D/3D) software to systematically study the influence of various homogenous soil types and subsurface heterogeneity on recharge from drywells under constant head conditions. The mean cumulative infiltration (〈em〉μI〈/em〉) and recharge (〈em〉μR〈/em〉) volumes increased with an increase in the saturated hydraulic conductivity (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si13.svg"〉〈msub〉〈mi〉K〈/mi〉〈mi〉s〈/mi〉〈/msub〉〈/math〉) for various homogeneous soils. Subsurface heterogeneity was described by generating ten stochastic realizations of soil hydraulic properties with selected standard deviation (〈em〉σ〈/em〉), and horizontal (〈em〉X〈/em〉) and vertical (〈em〉Z〈/em〉) correlation lengths. After 365 days, values of 〈em〉μI〈/em〉, 〈em〉μR〈/em〉, and the radius of the recharge area increased with 〈em〉σ〈/em〉 and 〈em〉X〈/em〉 but decreased with 〈em〉Z〈/em〉. The value of 〈em〉μR〈/em〉 was always smaller for a homogeneous than a heterogeneous domain. This indicates that recharge for a heterogeneous profile cannot be estimated with an equivalent homogeneous profile. The value of 〈em〉μR〈/em〉 was always smaller than 〈em〉μI〈/em〉 and correlations were highly non-linear due to vadose zone storage. Knowledge of only infiltration volume can, therefore, lead to misinterpretation of recharge efficiency, especially at earlier times. The arrival time of the wetting front at the bottom boundary (60 m) ranged from 21 to 317 days, with earlier times occurring for increasing 〈em〉σ〈/em〉 and 〈em〉Z〈/em〉. The corresponding first arrival location can be 0.1–44 m away from the bottom releasing point of a drywell in the horizontal direction, with greater distances occurring for increasing 〈em〉σ〈/em〉 and 〈em〉X〈/em〉. This knowledge is important to accurately assess drywell recharged performance, water quantity, and water quality.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0022169420300299-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 16 January 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Advances in Water Resources〈/p〉 〈p〉Author(s): Vitali Diaz, Gerald A. Corzo Perez, Henny A.J. Van Lanen, Dimitri Solomatine, Emmanouil A. Varouchakis〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The spatiotemporal monitoring of droughts is a complex task. In the past decades, drought monitoring has been increasingly developed, while the consideration of its spatio-temporal dynamics is still a challenge. This study proposes a method to build the spatial tracks and paths of drought, which can enhance its monitoring. The steps for the drought tracks calculation are (1) identification of spatial units (areas), (2) centroids localisation, and (3) centroids linkage. The spatio-temporal analysis performed here to extract the areas and centroids builds upon the Contiguous Drought Area (CDA) analysis. The potential of the proposed methodology is illustrated using grid data from the Standardized Precipitation Evaporation Index (SPEI) Global Drought Monitor over India (1901-2013), as an example. The method to calculate the drought tracks allows for identification of drought paths delineated by an onset and an end in space and time. Tracks, severity and duration of the drought are identified, as well as localisation (onset and end position), and rotation. The response of the drought tracking method to different combinations of parameters is also analysed. Further research is in progress to set up a model to predict the drought tracks for particular regions across the world, including India.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0309170819306542-fx1.jpg" width="301" alt="Image, graphical abstract" title="Image, graphical abstract"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: March 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 582〈/p〉 〈p〉Author(s): Huan Wang, Jia Xin, Xilai Zheng, Min Li, Yunhai Fang, Tianyuan Zheng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Artificial recharge of groundwater is an effective strategy for supplementing groundwater resources. It is noteworthy that most artificial recharge facilities suffer from clogging problems, which mainly result from suspended particles or bacteria in the recharge water. In this study, percolation experiments in sand columns were used to investigate the combined effects of suspended particles and bacteria on the permeability of porous media, which has been ignored in the past. During the recharge process, it took a much shorter period of time (3 h) for a particle-bacteria group (PBG) to achieve a relative hydraulic conductivity of 0.30 compared with a particle-only group (PG) (28 h) and a bacteria-only group (BG) (3.5 h). A combination of relevance analysis, pathway analysis, electron microscopy, and high-throughput sequencing were employed to identify the key controlling factors in the occurrence of clogging and the governing mechanisms under the co-existence of particles and bacteria. The dominant genera of the PBG included 〈em〉Acinetobacter〈/em〉, 〈em〉Sphingobacterium〈/em〉, 〈em〉Comamonas〈/em〉 and 〈em〉Elizabethkingia〈/em〉. These microbes displayed a poor ability for movement and high adhesion, which facilitated the clogging process for the PBG. The results indicated that bacterial cell growth and particle accumulation contributed to a reduction in 〈em〉K’〈/em〉 both separately and interactively during the recharge process (0–3 h), but that polysaccharide produced by bacteria began to have an impact during the later stages (stage II: 0.5–1 h and stage III: 1–3 h). The development of clogging in the PBG was primarily controlled by van der Waals forces, electrostatic repulsion and bridging during stage I (0–0.5 h). During the later stages, hydrogen bonds and polymerization of extracellular polymeric substances became the governing factors. These results provide an evaluation of clogging under the coexistence of suspended particles and bacteria, having implications for field-based artificial recharge.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0022169420300147-ga1.jpg" width="323" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: March 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 582〈/p〉 〈p〉Author(s): Ping Yang, Hong Yang, Derrick Y.F. Lai, Qianqian Guo, Yifei Zhang, Chuan Tong, Chaobin Xu, Xiaofei Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nitrous oxide (N〈sub〉2〈/sub〉O) is one of major potent long-lived atmospheric greenhouse gases (GHGs) with a global warming potential of approximately 300 times that of carbon dioxide (CO〈sub〉2〈/sub〉) over a 100-year timespan. To date, only several studies have explored the contribution of N〈sub〉2〈/sub〉O emission from aquaculture systems to global emission, but with large uncertainty. In this study, the spatiotemporal distribution of dissolved N〈sub〉2〈/sub〉O concentrations along the water column within ponds, and the N〈sub〉2〈/sub〉O fluxes over the whole annual cycle were determined in the shrimp ponds in the Min River Estuary, Southeast China. Our results showed that N〈sub〉2〈/sub〉O concentrations did not differ among sampling depths, but varied significantly among sampling dates. The temporal variation of N〈sub〉2〈/sub〉O concentration was significantly correlated with the concentrations of N-NH〈sub〉4〈/sub〉〈sup〉+〈/sup〉 and total dissolved nitrogen. The one year study found an annual mean N〈sub〉2〈/sub〉O emission of 57.63 μg N〈sub〉2〈/sub〉O m〈sup〉−2〈/sup〉 h〈sup〉−1〈/sup〉 that was equivalent to an annual emission of 504.9 mg N〈sub〉2〈/sub〉O m〈sup〉−2〈/sup〉 yr〈sup〉−1〈/sup〉, demonstrating the aquaculture ponds as an important source of atmospheric N〈sub〉2〈/sub〉O. The N〈sub〉2〈/sub〉O fluxes during the non-aquaculture period were one to three orders larger than those in the aquaculture period, and accounted for approximately 97% of the annual total emissions from aquaculture ponds. Our results showed that the N〈sub〉2〈/sub〉O emission during the non-aquaculture period should not be overlooked owing to its marked contribution to the annual N〈sub〉2〈/sub〉O budget in mariculture ponds. Further studies on N〈sub〉2〈/sub〉O production dynamics including the abundance and activity of nitrifying and denitrifying bacteria in coastal aquaculture ponds are needed to improve our understanding of N〈sub〉2〈/sub〉O biogeochemical cycle and facilitate strategies to reduce N〈sub〉2〈/sub〉O emission.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: March 2020〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 582〈/p〉 〈p〉Author(s): Aderonke O. Adegbule, Tohren C.G. Kibbey〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The focus of this work was on understanding the impact of evaporation on the capillary pressure-saturation (〈em〉P〈sub〉c〈/sub〉-S〈/em〉) state of a porous medium. Evaporation is ubiquitous near the ground surface in the vadose zone, but little is known about how evaporation impacts the relationship between capillary pressure and saturation. The hypothesis driving the work was that the 〈em〉P〈sub〉c〈/sub〉-S〈/em〉 relationship is the result of an equilibrium between evaporative water loss, capillary forces, and the upward flow of water to replenish evaporated water. Experiments were conducted using two different porous media, a coarse sand and a nylon membrane with a 20 μm pore size. Long-term evaporation experiments were conducted using different configurations to control evaporation within the media. Results found that increased accessibility to evaporation caused saturation in drainage 〈em〉P〈sub〉c〈/sub〉-S〈/em〉 curves to decrease over time, causing the curves to become closer to imbibition 〈em〉P〈sub〉c〈/sub〉-S〈/em〉 curves. In the membrane, the high external surface area to pore volume ratio caused changes in evaporative flux to produce rapid changes in the 〈em〉P〈sub〉c〈/sub〉-S〈/em〉 state of the medium. One implication of the work is that results suggest that long-term drainage experiments in vented columns may not necessarily provide a meaningful measurement of static 〈em〉P〈sub〉c〈/sub〉-S〈/em〉 curve, but rather may be impacted by evaporation.〈/p〉〈/div〉 〈/div〉