Groundwater Hydrology in Karst Media: Resources and Sustainability in Engineering

Dear Colleagues,

This Special Issue focuses on the karst formations and core topics related to resource sustainability and exploitation. A thorough understanding of karst is crucial for the proper planning and management of water resources, as limestone aquifers hold some of the world's largest potable water reservoirs, exemplified by karst springs used for water supply. This understanding is also vital for adapting to climate change, emphasizing groundwater management. Methods for calculating and assessing natural recharge in karst aquifers emerge as valuable tools.

Initial studies on aquifers, particularly karst aquifers, focus on identifying and assessing their resources. Modelling the karst system over time is essential to establish an accurate hydraulic balance. In karst hydrogeology, when only spring hydrographs are available, mathematical models of reservoirs or precipitation-runoff can reconstruct historical flow series.

The second phase involves understanding the hydrodynamic behavior of karst systems under natural conditions. This includes mapping flows, quantifying transit times with tracer tests, estimating renewal times, and assessing reserves. Karst aquifers have unique complexities, requiring specific techniques beyond classical hydrogeological methods for their study and exploration.

Springs, natural discharge points for groundwater, have been preferred for drinking water since ancient times due to their reliability and quality. Some springs also hold significant ecological, tourist, and historical value. However, groundwater exploitation has reduced or eliminated many springs worldwide, prioritizing their protection while allowing local groundwater use.

Karst occurs in various geological contexts with different storage and flow conditions, necessitating a thorough understanding of local conditions. Integrating geomorphological and hydrological investigations in karst studies is essential. Ancient endokarst formations often influence groundwater flow, and understanding hydrogeomorphological evolution is crucial for understanding current karst system behavior. Hydrogeology and speleology are inseparably linked, with the study of speleogenesis and regional cave systems contributing to understanding karst aquifer evolution.

Groundwater quality and the vulnerability of karst aquifers to contamination are significant issues, potentially limiting their use. The relationship between groundwater, hydrogeology and protected areas, and minor hydraulic works in springs and fountains is also a topic of concern in this Special Issue.

Groundwater poses challenges in civil engineering, with construction often encountering hydrogeological incidents like leaks from dams in karst terrains and water ingress into tunnels. Gypsum and evaporitic rocks, due to their high solubility, can be affected by new karstification within the lifespan of an engineering project. Understanding geological and hydrogeological problems is crucial to avoid significant consequences, lying at the intersection of hydrogeology, applied geology, and geotechnics.

We encourage potential authors to submit original quality research articles and reviews on (but not limited to) the following topics:

• Karst hydrogeology: analysis of karst drainage systems; karst and geomorpholoy; water tracings test; speleogenesis: the development of cave systems; and paleohydrogeology.
• Water resources: karst water resources and sustainability; determination of available water resources; natural recharge in karst; and climate change and water resources.
• Karst spring: sustainability and management of springs; spring discharge hydrograph; spring modelling; springwater geochemistry and treatment; delineation of spring protection zones; utilization and regulation of springs; and architectural heritage
• Engineering and water problems in construction: dams and reservoirs; tunneling in karst; karst engineering in evaporites; and water and sinkhole.
• Karst and environment: wetlands in karst; karst hydrology in national parks; water quality; pollution; groundwater vulnerability; and underground flow and transport of pollutants.

We look forward to receiving valuable contributions.

Dr. Eugenio Sanz
Prof. Dr. Juan Carlos Mosquera Feijoo
Prof. Dr. Ignacio Menéndez-Pidal
Guest Editors

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