Abstract: Identification of the location and intensity of groundwater pollution source contributes to the effect of pollution remediation, and is called groundwater contaminant source identifcation. This is a kind of typical groundwater inverse problem, and the solution is usually ill-posed. Especially considering the spatial variability of hydraulic conductivity field, the identification process is more challenging. In this paper, the solution framework of groundwater contaminant source identification is composed with groundwater pollutant transport model (MT3DMS) and a data assimilation method (Iterative local update ensemble smoother, ILUES). In addition, Karhunen-Loève expansion technique is adopted as a PCA method to realize dimension reduction. In practical problems, the geostatistical method is usually used to characterize the hydraulic conductivity feld, and only the contaminant source information is inversely calculated in the identifcation process. In this study, the identification of contaminant source information under Kriging K-field is compared with simultaneous identification of source information and K-field. The results indicate that it is necessary to carry out simultaneous identification under heterogeneous site, and ILUES has good performance in solving high-dimensional parameter inversion problems.
Abstract: Whether groundwater resources can be sustainably utilized is largely determined and characterized by hydrogeological parameters. Estimating the groundwater recharge is one of the essential parameters for managing water resources and protecting water resources from contamination. This study researched the spatial and temporal variation of groundwater recharge in the Thepkasattri sub-district through integrating chloride mass balance (CMB) and water table fluctuation (WTF) methods. The chloride content of representative rainfall and groundwater samples was analyzed. Besides, WTF method was adopted from groundwater level data from 2012 to 2015. According to the CMB method, the mean recharge was estimated to be 1 172 mm per year, accounting for 47% of the annual rainfall. Moreover, the estimated recharge from the WTF method took 26% of annual rainfall in 2015. The recharge was underestimated according to the WTF method, because of the uncertainty in specific yield estimates and the number of representative wells in the study area. Moreover, the correlation between rainfall and water table fluctuation data indicated the positive linear relationship between two parameters. The spatial recharge prediction indicated that recharge was higher (1 200-1 400 mm/yr) in the eastern and western catchment, while that in the central floodplains was between 800 mm/yr and 1 100 mm/yr. In addition, low recharge value between 450 mm/yr and 800 mm/yr was observed in the south-west part of Thepkasattri. The spatial variation of recharge partly reflects the influences of land use and land cover of the study area.
Abstract: There are rising interests in the utility of groundwater in various aspects, which is capable of triggering problematic issues. The excessive exploitation for anthropologic uses, without regards to aquifer capacity, will decreases the water table as well as capacity of groundwater in the aquifer. This research is aimed to provide aquifer model of underground water by consideration of various environmental factors, with the propensity of being modeled, in an attempt to predict groundwater conditions in subsequent years. The purpose of this research is to forecast water requirements, availability, as well as three-dimensional model of groundwater depth in Kemuning, Indragiri Hilir Regency-Indonesia between 2015 and 2022. Furthermore, various environmental factors, from aquifer profiles to anthropologic demand, are taken into account in the evaluated model, including water requirements, encompassing recharge and aquifer parameters, which consists of storativity and transmissivity. From anthropologic side are domestic requirements, trade, public facilities, agriculture, and livestock. The results show that groundwater availability in Kemuning is to be safe condition, and average difference is 1.06×108 m3/yr. The coefficient of storativity and transmissivity are 16.514 m2/day and 9 897.26 m2/day, respectively, while the average depth was recorded as 2.8965 m to 10.4927 m.
Abstract: Longkou City is a coastal area, and lacks water resources. The overexploitation of groundwater causes seawater intrusion. At present, seawater intrudes an area of 68 km2. With the decrease of groundwater extraction, the seawater intrusion area has generally declined. The paper expounds the development process of seawater intrusion as well as the corresponding prevention and control measures of using groundwater replenishment and groundwater throttling in Longkou City. In view of the seawater intrusion problem in Longkou City, some adaptive management countermeasures are put forward, which include: Adjusting industrial and agricultural structure, promoting economic and social development to match water resources; improving water usage structure, optimizing the utilization of water resources; advancing the construction of a water-saving society, using water resources efficiently; implementing inter-basin water transfer, using water resources rationally; developing and utilizing unconventional water sources, making full use of water resources; strengthening water infrastructure construction, increasing the development and utilization potential of water resources; carrying out ecological restoration, protecting water resources and ecological environment; improving the management informationalization level, strengthening the capabilities of groundwater monitoring and management; increasing publicity, improving public awareness of participation.
Abstract: Groundwater exploitation has been regarded as the main reason for land subsidence in China and thus receives considerable attention from the government and the academic community. Recently, building loads have been identified as another important factor of land subsidence, but researches in this sector have lagged. The effect of a single building load on land subsidence was neglected in many cases owing to the narrow scope and the limited depth of the additional stress in stratum. However, due to the superposition of stresses between buildings, the additional stress of cluster loads is greater than that of a single building load under the same condition, so that the land subsidence caused by cluster loads cannot be neglected. Taking Shamen village in the north of Zhengzhou, China, as an example, a finite-difference model based on the Biot consolidation theory to calculate the land subsidence caused by cluster loads was established in this paper. Cluster loads present the characteristics of large-area loads, and the land subsidence caused by cluster loads can have multiple primary consolidation processes due to the stress superposition of different buildings was shown by the simulation results. Pore water migration distances are longer when the cluster loads with high plot ratio are imposed, so that consolidation takes longer time. The higher the plot ratio is, the deeper the effective deformation is, and thus the greater the land subsidence is. A higher plot ratio also increases the contribution that the deeper stratigraphic layers make to land subsidence. Contrary to the calculated results of land subsidence caused by cluster loads and groundwater recession, the percentage of settlement caused by cluster loads in the total settlement was 49.43% and 55.06% at two simulated monitoring points, respectively. These data suggest that the cluster loads can be one of the main causes of land subsidence.
Abstract: Soil vapor extraction (SVE), the most common, efficient and economical means of remediation, is an in-situ remediation technique for removing volatile pollutants from unsaturated soil. The paper briefly introduced the technological rationale and cha?racteristics, summarized the theories and application research for SVE at home and abroad, and made the expectations and suggestions for the research on SVE. The international scholars have systematically researched the influence factors, remediation mechanism and numerical simulation of SVE. At present, SVE has been mostly integrated with other techniques to form enhanced SVE techniques, such as thermally enhanced SVE and AS-SVE (Air sparging-SVE), to be used for the field remediation widely. Compared with foreign countries, researches of Chinese scholars mainly focus on the laboratory research, especially on the influence factors, but rarely study the SVE model and the mass transfer mechanism of pollutant in SVE process. The SVE pilot studies are rare in China, and the field application has not been reported. In view of this situation, Chinese scholars in the future research can focus on the following aspects: (1) strengthening the research and systematized summary of SVE technical parameters and related knowledge; (2) strengthening the research on the mechanism and model of gas-phase mass transfer of pollutants in soil during SVE process; (3) strengthening the research on the enhanced SVE techniques and its application to actual site remediation.
Abstract: At present, due to shortage of water resources, especially in arid and semiarid areas of the world such as Iran, exploitation of groundwater resources with suitable quality for drinking is of high importance. In this regard, contamination of groundwater resources to heavy metals, especially arsenic, is one of the most important hazards that threaten human health. The present study aims to develop an approach for presenting the groundwater quality of Sirjan city in Kerman Province, based on modern tools of spatial zoning in the GIS environment and a fuzzy approach of evaluating drinking water in accordance with the standards of world health organization (WHO). For this purpose, qualitative data related to 22 exploitation wells recorded during 2002 to 2017 were used. In addition, fuzzy aggregate maps were prepared in two scenarios by neglecting and considering arsenic presence in groundwater resources. The results showed a decrease in groundwater quality over time. More specifically, neglecting the presence of arsenic, in 2002, all drinking wells in the area were located in an excellent zone, while in 2017 a number of operation wells were located in the good and medium zone. Also, the final map, considering the presence of arsenic as a limiting factor of drinking water, indicated that parts of the southern regions of the plain would be the best place to dig wells for drinking water. Therefore, the use of new methods can contribute significantly to the usage of groundwater aquifers and provide a good view of the aquifer water quality.
Abstract: The limited knowledge of the variations, both spatial and temporal, of the flow patterns at the watershed level invariably leads to poor space management, generating great and often irreversible damage. Therefore, measuring peak flows appears to be not only important but even essential. Due to the absence of hydrometric stations at the outlet of the sub-basins that are part of comprehensive prevention strategy, and were established because of the high vulnerability of the city of Batna, this study provides a transformation model of rainfall into flows in the Batna watershed. This work aims to model the transformation of rainfall into flows. To estimate the Q max, two formulas were used, and Turazza’s seems to be the most adequate, because it demonstrates a cumulative sub-basins flow close to the result recorded by the only hydrometric station at the outlet of Batna Watershed. From this modeling, it is possible to estimate the extreme quantiles with the return periods of 10, 20, 50 and 100 years for each sub-basin. Its purpose is to help design of hydraulic works and increase the resilience of development projects that might be exposed to floods.
Abstract: Al-Mansourieh zone is a part of Al-Khalis city within the province of Diyala and located in the Diyala River Basin in eastern Iraq with a total area about 830 km2. Groundwater is the main water source for agriculture in this zone. Random well drilling without geological and hydraulic information has led the most of these wells to dry up quickly. Therefore, it is necessary to estimate the levels of groundwater in wells through observed data. In this study, Alyuda NeroIntelligance 2.1 software was applied to predict the groundwater levels in 244 wells using sets of measured data. These data included the coordinates of wells (x, y), elevations, well depth, discharge and groundwater levels. Three ANN structures (5-3-3-1, 5-10-10-1 and 5-11-11-1) were used to predict the groundwater levels and to acquire the best matching between the measured and ANN predicted values. The coefficient of correlation, coefficient determination (R2) and sum-square error (SSE) were used to evaluate the performance of the ANN models. According to the ANN results, the model with the three structures has a good predictability and proves more effective for determining groundwater level in wells. The best predictor was achieved in the structure 5-3-3-1, with R2 about 0.92, 0.89, 0.84 and 0.91 in training, validation, testing and all processes respectively. The minimum average error in the best predictor is achieved in validation and testing processes at about 0.130 and 0.171 respectively. On the other hand, the results indicated that the model has the potential to determine the appropriate places for drilling the wells to obtain the highest level of groundwater.