Hydrodynamical and Hydrochemical Assessment of Pumped-Storage Hydropower (PSH) Using an Open Pit: The Case of Obourg Chalk Quarry in Belgium

Pumped storage hydropower (PSH) enables the temporary storage of energy, including from intermittent renewable sources, and provides answers to the difficulties related to the mismatch between supply and demand of electrical energy over time. Implementing a PSH station requires two reservoirs at different elevations and with large volumes of water. The idea of using old, flooded open-pit quarries as a lower reservoir has recently emerged. However, quarries cannot be considered as impervious reservoirs, and they are connected to the surrounding aquifers. As a result, PSH activities may entail environmental impacts. The alternation of the pumping–discharge cycles generates rapid and periodic hydraulic head fluctuations in the quarry, which propagate into the surrounding rock media forcing the exchange of water and inducing the aeration of groundwater. This aeration can destabilize the chemical balances between groundwater and minerals in the underground rock media. In this study, two numerical groundwater models based on the chalk quarry of Obourg (Belgium) were developed considering realistic pumping–discharge scenarios. The aim of these models was to investigate the hydrodynamic and hydrochemical impact of PSH activities on water inside the quarry and in the surrounding rock media. Results showed that (1) water exchanges between the quarry and the adjacent rock media have a significant influence on the hydraulic head, (2) the frequency of the pump–discharge scenarios influence the potential environmental impacts, and (3), in the case of chalk formations, the expected impact of PSH on the water chemical composition is relatively limited around the quarry. Results highlight that those hydrogeological and hydrochemical concerns should be assessed when developing a project of a PSH installation using a quarry as a lower reservoir, considering all particularities of the proposed sites.

Hydrochemical Characteristics and Ion Sources of River Water in the Upstream of the Shiyang River, China

As the largest tributary of the Shiyang River, with the average annual inflow of total runoff accounting for 23%, the Xiying River has representative of mountain runoff of inland rivers in the Northwest of China. Using samples collected in this basin from September 2016 to October 2017, the water chemical composition and ion source characteristics of river were studied. The results show that the river is weakly alkaline, the average pH is 8.0 and the TDS is 179.29 mg·L-1. With the elevation decreasing along the river, the TDS of main stream tend to increase firstly and then decrease, but those of TDS of each tributary decrease, and latter is lower than the former. Affected significantly by the flow, the lowest value of ion concentration in river occurs in summer, and the highest occurs in autumn and winter. The hydrochemical type of river is CaMg-HCO3. In the river, the order of cation mass concentration is NH4+<K+<Na+<Mg2+<Ca2+, and that of anion is F-<NO3-<Cl-<SO42-<HCO3-. The sources of ions in river are mainly from the weathering of Silicates and Carbonates. With the elevation decreasing along the river, the influence of Silicates on the inflowing tributaries is gradually strengthened.

Application of Partial Least Squares-Discriminate Analysis Model Based on Water Chemical Compositions in Identifying Water Inrush Sources from Multiple Aquifers in Mines

Mine water inrush seriously threatens the safety of coal mine production. Quick and accurate identification of mine water inrush sources is of great significance to preventing mine water hazards. This paper combined partial least squares-discriminate analysis (PLS-DA) with inrush water chemical composition to identify the source of water inrush from multiple aquifers in mines. The Renlou Coal Mine in the Linhuan mining area was selected for this study, and seven conventional water chemical compositions from 54 water samples in three aquifers were collected and tested, of which 45 water samples were used to establish the PLS-DA discriminant model, and nine were used to test the prediction effect. To improve model accuracy and predictive ability, hierarchical clustering analysis method was used to eliminate seven unqualified water samples to reduce the errors caused by improper data. PCA and PLS-DA methods were used to analyze and process the remaining water sample data, and on the basis of PCA analysis, the remaining 38 water samples were used to establish the PLS-DA discriminant model. The model was validated using permutation and external prediction tests. The research shows the following results: (1) Both PCA and PLS-DA methods can distinguish water samples from three different water sources, but the classification effect of PLS-DA was better than PCA because it can strengthen the difference of water chemical composition between different water sources. (2) The correct discrimination rate of the PLS-DA discriminant model was as high as 100%, and permutation tests showed that the model was not overfit. External validation found that the model had good stability and discrimination. (3) HCO3- and total dissolved solids (TDS) were the most important differential marker compositions that affected the discrimination results based on Variable Importance for the Projection (VIP) scores. The discriminant model established in this study combined the advantages of principal component analysis and multiple regression analysis, providing a new method for accurately identifying the sources of water inrush in mines.

Assessing the Pollution Level in the Kuban River Basin by Multivariate Cluster Analysis

Considering features of hydrological conditions for hydro-chemical system, this paper analyses the performance of the hydro-ecological status of the Kuban river basin.. The results of the study on water chemical composition depending on the distance from the source are presented. By comparing the results with the reference values of water quality, increased aluminium, zinc, and copper content was established. Respective dendrograms of hydro-ecological studies obtained according to performed analysis for the Kuban River and its tributaries are presented. The relevance of the findings received is p<0.0005 and the correlation coefficient corresponds to 0.935...1. The results of multivariate cluster analysis showed that the Kuban basin has an increased content of particular heavy metals such as aluminium, copper, and zinc.

Evaluation of treated wastewater irrigation on the productivity of wheat

The major objective of this research work is to propose the initial environmental impact assessment concerning the utilization of treated wastewater for two different varieties of wheat production. The study analyzed the soil chemical composition before and after irrigation at two different depths (0-30 cm & 30-60 cm). Water chemical composition is also analyzed for controlled water, treated water of Abu Dhabi and Al Ain. Wheat plant chemical composition present in the head, root, and shoot for both the varieties is analyzed. The levels of Ca, Mg, Na and CI in soil have increased after irrigation with controlled water. The presence of cations and anions in the soil are slightly higher in the treated water of Abu Dhabi. Ca, Na, CI and SO4 are found to be significantly higher after irrigation with treated wastewater of Al Ain. The plant chemical composition of head, root and shoot ND fiber, AD fiber, Crude protein and Macro elements have shown no significant differences across the three types of water and two varieties of wheat production. The correlations between RBS limits and the three types of water considered in the study are negative. The results revealed that the differences in chemical composition between RBS limits, controlled, treated wastewater of Abu Dhabi and Al Ain are statistically significant with particular reference to trace and heavy metals. Concerning water chemical composition, the study concludes that the correlation between controlled water and treated wastewater of Al Ain is strong when compared to Abu Dhabi.

Identification of Mine Water Inrush Source Based on PCA-FDA: Xiandewang Coal Mine Case

When mine water inrush accidents occur, timely and accurately identifying the water inrush source plays an important role in determining the cause of water inrush and making a solution to a disaster. According to the differences of water chemical composition in each water sources of mine, eight kinds of indicators of water chemical composition were selected as sample variables for water inrush source identification. On this basis, an identification model of water inrush source was established by using principal component analysis (PCA) and Fisher discriminant analysis (FDA) combined. The model was used to identify the water inrush source of 14 groups of training samples and 12 groups of samples to be judged in different water sources of the Xiandewang coal mine, and it was compared with the results of the conventional identification model which used the FDA method. Results of this study showed that having processed data by using the PCA method can effectively eliminate the effects of information superposition between sample indicators, and the identification accuracy of mine water inrush source was significantly increased. Related study in this paper can provide some basis and reference for the study of mine water inrush source identification technology.

The determination of the nitrogen-containing ions concentrations dynamics in the oxbow of Ishimchik to assess the impact of 2016–2017 floods

This paper presents the results of the ecological state study of oxbow Ishimchik, located in Ishim, Tyumen Region. The paper presents data on the nitrogen-containing ions concentrations dynamics in water samples of oxbow Ishimchik over the summer-autumn of 2017, the content of which is an important indicator of the water chemical composition. The presence of nitrate ions, nitrite ions and ammonia in high concentrations in the samples usually indicates that the reservoir suffers from contamination by household, agricultural and industrial waste. In 2016 and 2017 a large amount of water from heavy floods came to the oxbow, which could significantly increase the concentration of mineral forms of nitrogen. The main concern is the flood of 2016 as to stop the Ishim private sector flooding a channel was dug for discharge of floodwaters from the town-affected part into the oxbow. To determine the content of nitrogen-containing ions, the photometry method was used. The results of a chemical analysis show that the content of ammonium and ammonia cations (total), nitrite anions and nitrate anions is less than maximum permissible concentration as well as there is a change in the prevailing mineral form of nitrogen from redoxidized to oxidized.