[New phreatic and stygobitic hydrobiids from the Northern Apennines in Piedmont, Liguria and Emilia-Romagna (Gastropoda: Caenogastropoda: Hydrobiidae)]

Five new species of phreatic and stygobitic hydrobiids are here described for the Ligurian- Piedmontese and Emilian Apennines. Two species belong to the genus Alzoniella: Alzoniella borberensis n. sp., endemic to the sub-basin of the Borbera and Spinti streams, and to the lower stretch of the Scrivia stream, in the province of Alessandria, and Alzoniella isoensis n. sp., limited to the middle course of the Scrivia stream and to the basin of the Polcevera stream, on the Tyrrhenian sector of the Genoa province. Three species belong to the genus Fissuria: Fissuria globosa n. sp., widespread throughout the sub-basin of the Scrivia stream (Genoa and Alessandria provinces), as well as in other Apennine watercourses of the provinces of Alessandria, Piacenza, Parma and Reggio Emilia; Fissuria varicosa n. sp., present in the same area of Alzoniella borberensis n. sp., but also found in the Nure and Arda streams (Piacenza province) and in the Stirone stream (Parma province), and Fissuria sossoi n. sp., limited to the sub-basin of the Stura di Ovada streams (Genoa province). The first species, assigned to the genus Alzoniella Giusti & Bodon 1984 based on its anatomical characters, has a shell with peristome detached from the last whorl, such as that of other phreatic species already known for eastern Liguria and central Italy, but differs from these in the shorter shell. The shape of the shell of A. borberensis n. sp. resembles that of other crenal or stygobitic species, widespread in northern Italy. A. isoensis n. sp., is very similar to A. borberensis, although the peristome is not sinuous superiorly on the outer edge of the shell, but differs sharply in the anatomical characters. The other taxa with valvatoid shells here described, can be ascribed to the genus Fissuria Boeters 1981 based on their anatomical characters, and show some peculiarities of the male genital tract that distinguish them from the other congeneric species so far known for southern Europe. The three new species of Fissuria differ mainly in the characters of the shell, more or less globose in F. globosa n. sp., more conical in F. sossoi n. sp. and more flattened in F. varicosa n. sp.; the latter is also characterized by the presence of a marked varix behind the peristome. Altogether, these new species can be defined as phreatic, as they colonize groundwater near watercourses; only A. isoensis n. sp. has a wider ecology, as it also lives in karst groundwater and groundwater in rocks permeable by fracking. [Article in Italian]

Vulnerability Assessment as a Basis for Sanitary Zone Delineation of Karst Groundwater Sources—Blederija Spring Case Study

The application of groundwater vulnerability methods has great importance for the sanitary protection zones delineation of karstic sources. Source vulnerability assessment of karst groundwater has mainly relied on the European approach (European Cooperation in Science and Technology—COST action 620), which includes analysis of the K factor, which refers to water flow through the saturated zone of the karst system. In the paper, two approaches to groundwater vulnerability assessment have been applied, COP + K and TDM (Time-Dependent Model) methods, to produce the most suitable source vulnerability map that can be transformed into sanitary protection zones maps. Both methods were tested on the case example of Blederija karst spring in Eastern Serbia. This spring represents a classical karst spring with allogenic and autogenic recharge. Dual aquifer recharge points out the necessity for the inclusion of the vulnerability assessment method created especially for the assessment of karst groundwater. Obtained vulnerability maps show similar results, particularly in the spring and the ponor areas, and these zones are most important for future protection. The COP + K method brings out three vulnerability classes that can be directly transformed into three sanitary protection zones. Contrary to the previous one, the TDM method uses water travel time as a vulnerability degree. The results show that the final map can be easily used to define sanitary zones considering different national legislation.

Assessment of Ensemble Models for Groundwater Potential Modeling and Prediction in a Karst Watershed

Due to numerous droughts in recent years, the amount of surface water in arid and semi-arid regions has decreased significantly, so reliance on groundwater to meet local and regional demands has increased. The Kabgian watershed is a karst watershed in southwestern Iran that provides a significant proportion of drinking and agriculture water supplies in the area. This study identified areas with karst groundwater potential using a combination of machine learning and statistical models, including entropy-SVM-LN, entropy-SVM-SG, and entropy-SVM-RBF. To do this, 384 karst springs were identified and mapped. Sixteen factors that are related to karst potential were identified from a review of the literature, and these were compiled for the study area. The 384 locations were randomly separated into two categories for training (269 location) and validation (115 location) datasets to be used in the modeling process. The ROC curve was used to evaluate the modeling results. The models used, in general, were good at determining the location of karst groundwater potential. The evaluation showed that the E-SVM-RBF model had an area under the curve of 0.92, indicating that it was most accurate estimator of groundwater potential among the ensemble models. Evaluation of the relative importance of each of the 16 factors revealed that land use, a vector ruggedness measure, curvature, and topography roughness index were the most important explainers of the presence of karst groundwater in the study area. It was also found that the factors affecting the presence of karst springs are significantly different from non-karst springs.

Hydrogeochemistry Evidence for Impacts of Chemical Acidic Wastewater on Karst Aquifer in Dawu Water Source Area, Northern China

The study of the hydrochemical characteristics and the water–rock interaction of karst groundwater is very important for the rational exploitation of karst groundwater and its pollution control. In this paper, the systematic clustering method was used to analyze the hydrochemical characteristics of different types of groundwater, combined with hydrochemical graphic analysis and correlation analysis to explore the impact of chemical acidic wastewater on the evolution of karst aquifer in the Dawu water source area, northern China. The results show that the chemical acid wastewater, sourcing from discharges/spillages from the local chemical industries, has different degrees of pollution impact on karst groundwater, causing the total hardness of all karst groundwater and the total dissolved solids, Cl− and SO42− in nearly half of the karst groundwater to exceed the quality indexes of class III water in China’s standard for groundwater quality (GB/T 14848-2017). Hydrochloric acid and sulfuric acid in the wastewater can be buffered by the dissolution of carbonate rocks, resulting in a nearly neutral pH (pH-buffering effect) and an increase in Ca2+, Mg2+, Sr, Cl− and SO42− concentrations in karst groundwater.

Application of Hydrochemical and Isotopic Data to Determine The Origin and Circulation Conditions of Karst Groundwater in An Alpine and Gorge Region in The Qinghai–Xizang Plateau: A Case Study Of Genie Mountain

Understanding of the recharge origin, runoff channels, and discharge characteristics of karst groundwater is very important for construction of underground projects and identification of water supply targets. Complex structural systems, lithological differences, and extreme heterogeneity of aquifers combine to create a complex karst aquifer structure in alpine and gorge areas; however, because of the topography, direct investigation of aquifer structure is difficult. In this study, field survey, hydrochemical, and isotopic data are analyzed to reveal the development of karst groundwater and to describe the karst water cycle in Genie Mountain, Qinghai–Xizang Plateau. The results show that atmospheric precipitation and melting ice and snow are the groundwater recharge sources, and groundwater circulation is shallow, with groundwater ages generally no more than 60 yr. The groundwater cycle can be divided into three levels: epikarst water circulation; mid to deep karst water circulation; and deep geothermal water circulation. The karst springs located in the outlet of the Huolong gully contain markedly higher levels of Na + and SO 4 2 − than other karst springs because of the leaching effect of groundwater on mirabilite. The presence of evaporites also indicates that the groundwater of Huolong gully is influenced by evaporation. The runoff of thermal springs undergoes deep circulation and is controlled by faults. This water mainly dissolves carbonate rock, with little influence of evaporation. This study shows that hydrochemical and isotopic methods can be used to discriminate different water types, and can be applied to study the characteristics of complex groundwater runoff in alpine and gorge areas.