Hydrogeology of Mangsri Cave, Gunungsewu Karst Area, Java Island, Indonesia

The Gunungsewu karst area is not only known for its unique landscape but also its recurring drought events. To meet the water supply, the local population utilizes several water potentials, namely doline pond, spring, and underground river. This study was designed to analyze the hydrogeological conditions of Mbangsri Cave, following its accidental discovery by the community at the end of 2018. The hydrogeological analysis was conducted by geological surveys, which consisted of rocks collection and structural measurements, cave mapping, and recharge area delineation based on remote sensing images acquired by unmanned aerial vehicles. The results showed that Mbangsri Cave, in the hydrogeological perspective, had low water resources potential. It is believed to be the result of (1) relatively small catchment area, (2) a fault in the southern part of Mbangsri Cave, creating a small groundwater basin, and (3) the thin epikarst layer, limiting the water storage.

An Intermittent Karst River: The Case of the Čikola River (Dinaric Karst, Croatia)

Intermittent and ephemeral streams (IRES) are responsible for transporting about half of the water on Earth’s surface. Their hydrological behavior is different in various landscapes. IRES are found more often in karst terrains than in any other regions, as a consequence of strong and direct interaction between groundwater and surface water. This paper presents a hydrogeological and hydrological analysis of the intermittent Čikola River and Spring catchment, which is located in deeply karstified and developed parts of the Dinaric karst in Croatia. Hydrological calculations determined that the catchment area covers approximately 300 km2 and very probably changes in accordance with rapid variations in groundwater level. The karst spring of the Čikola River is a cave, extracted for a public water supply with four drilled extraction wells. The results of the interrelated hydrological and hydrogeological analysis show interesting phenomena from an intermittent karst spring (cave) and its catchment, flowing downstream through a karst polje with several smaller confluences, then entering a karst canyon (where the river sinks during certain periods), and ending in an estuary before contributing to the larger Krka River. The research presented was based on water balance calculations, climatic and hydrological time series analyses, spring pumping tests, and thorough hydrogeological interpretation.

Time evolution of groundwater quality in Dehui City

The unreasonable development and utilization of groundwater in Dehui City, China, has resulted in poor groundwater quality conditions. Based on the collection of a large amount of groundwater chemical data and hydrogeological data collected by Dehui City from 1992 to 2015, this paper uses hydrogeological analysis, graphic and other methods and ArcGIS toolbox to analyze the groundwater quality of this City. The study shows that the concentration of groundwater chemical components in the vicinity of the Songhua River is decreasing with time, and the concentration of groundwater chemical components in other regions is increasing with time. The increase of chemical concentrations are affected by human activities and water-rock interaction. The decrease of groundwater chemical concentration in Songhua River area is caused by the mixing between dilute river water and groundwater.