•The nitrogen concentration in karst groundwater has spatial heterogeneity.•The redox characteristics of different karst aquifer media are heterogeneous.•Different karst aquifer media have different ...N transformation processes.
Karst aquifers, a significant source of drinking water worldwide, are vulnerable to anthropogenic pollutants because of their special hydrogeological conditions. However, distinguishing the nitrogen transformation process is difficult owing to the heterogeneity of karst media. Therefore, the process of nitrogen transformation in different karst aquifer media remains poorly understood. In this study, multiple stable isotopic and physicochemical indicators are combined, the sources of water and nitrogen are analysed, and the degree of openness and redox conditions of different media are discussed to elucidate the nitrate sources and N transformation in groundwater with different degrees of openness. Water isotopes indicate local meteoric groundwater origin. However, different karst aquifer media have different degrees of openness, resulting in the highest deuterium–oxygen isotope values in surface water, followed by conduit water, fissure water, and isolated cave water. Based on the evidence from isotope and physicochemical indicators, different karst aquifer media have different redox processes. Isolated cave water environments were under anoxic conditions dominated by sulfate reduction reactions. Fissure water was under temporary anoxic or sub-anoxic conditions dominated by denitrification reactions. Conduit water and karst surface water were between micro-oxygen and oxidising conditions, and nitrification was the key process. This phenomenon was observed because the diversity of karst media produces different conservation conditions and openness. The nitrate isotope and Bayesian mixing model indicate that the main sources of nitrate in karst groundwater in the study area are mostly associated with manure and sewage wastes, and a few are from soil organic nitrogen, atmospheric deposition, and chemical fertilizer. This study helps identify the migration and transformation patterns and processes of nitrogen in different karst aquifer media, providing a scientific basis for the restoration and remediation of contaminated karst groundwater.
•LuKARS – Land use change modeling in KARSt systems.•Construction of a hydrotope-based modeling approach for karst hydrological modeling.•Simulating spring discharge in a dolomite-dominated karst ...system.•Modeling land use change impacts in karst hydrological systems.
Hydrological models represent valuable tools to investigate the impacts of land use changes on water resources. Most commonly, distributed, physically-based models are applied for land use change impact studies in hydrology. However, providing a physically-based and detailed description of subsurface flows in karst systems is challenging. Lumped models, in contrast, are easy to implement and widely used in karst hydrological research, albeit not applicable for land use change impact studies. To overcome these limitations, we developed a new semi-distributed model LuKARS (Land use change modeling in KARSt systems) that lumps the predominant hydrotopes (i.e. distinct landscape units characterized by homogeneous hydrological properties as a result of similar land use and soil types) present in a catchment as independent, non-linear units. Flows from each hydrotope represent a specific response of the vadose zone (soil-epikarst-infiltration zone) in a defined recharge area. The saturated zone consists of a single linear storage unit recharged by each hydrotope independently. The main goal of this approach was to investigate land use change impacts in a dolomite karst system exploited for the water supply of the city of Waidhofen a.d. Ybbs (Austria) by changing the area covered by each hydrotope. Here, land use changes occured in the form of increasing spaces used for dolomite mining and at the expense of existing forest sites. With our parametrized model, we were able to reproduce the measured discharge in the largest spring of the Waidhofen karst system (Kerschbaum spring). Moreover, we succeeded in transferring the parametrized hydrotopes to other recharge areas (Hinterlug and Mitterlug) and validated the transferability of the modeling approach. Finally, we successfully showed the model’s applicability for land use change impact studies by validating the calibrated model in a period in which the space of the dolomite quarries in the Kerschbaum recharge area almost doubled. The results of our study show that an increase of the dolomite quarries negatively affects the water supply of the city of Waidhofen a.d. Ybbs.
Karst reservoirs are distributed widely in China, for which integrated geological, logging, testing, and seismic identification marks can be made and their ages can be determined using unconformity ...surfaces, the lithologic features, and paleobiology of cavern clastic fillings and element geochemistry. The karst reservoirs can be classified as buried hill karst, reef-bank karst, internal karst, bedding deep-underflow karst, vertical deep-infiltration karst, and hydrothermal fluid karst. The first three belong to base-level karsts, controlled by different-order sequence interfaces; the last three belong to nonbase-level karsts, which are controlled by tectonics and fracture. The division of karst facies should take full account of the internal relation of the base-level karsts and the nonbase-level karsts, the existence of deep-turbulent flow zones and the genetic type of karsts. There are many types of corrosion fluid in carbonate rocks in petroleum basins. It is important for the reservoir evaluation and prediction to reconstruct them and to analyze the genetic mechanics of the karst pore-cave-fracture and large-scale cave. As for the controlling factors for the karst development, the study of zonal exogenic forces should be enhanced while the study of azonal endogenic forces is emphasized.
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•Developing an integrated sediment source assessment index based on long series hydrologic signals.•Developing Karst Surface Characteristic Index based on karst desertification ...factors.•Karst Surface Characteristic Index is closely related to hydrological processes.•Clockwise hysteresis is the most frequent and efficient type of sediment transport.
The source and transport processes of suspended sediment are issues that require further study. The complex relationship between the integrated surface characteristics and the mechanisms of sediment sources and transport in heterogeneous karst watersheds remains unclear. This study proposes a comprehensive assessment framework for sediment sources that combines the surface characteristics of karst watersheds, such as exposed rock and shallow topsoil in karst areas. Additionally, the Karst Surface Characteristic Index (KSCI) is developed to evaluate the potential supply capacity of sediment in karst watersheds. The hysteresis index (HImid) is calculated using a long series of hydrological data to study runoff and sediment relationships in eight watersheds in the karst region of southern China. Results indicated that plan curvature, terrain relief, NDVI, and rock exposure contributed most to KSCI, with these four factors contributing 65%. The Q-SSC hysteresis analysis results based on 445 hydrological events showed that a clockwise hysteresis pattern was the most frequent and efficient pattern of sediment transport in the studied watershed (clockwise hysteresis pattern accounted for 72.3% of 445 hydrological events) owing to the limited sediment supply in the karst watersheds. The quantitative analysis results of HImid and KSCI showed that HImid was closely related to KSCI. With an increase in KSCI, a clockwise hysteresis pattern was more likely to appear, indicating that watershed characteristics exerted a significant influence on sediment transport velocity and efficiency. In terms of spatial distribution, near the outlet of the watershed or the river channel, high KSCI values were distributed, and clockwise hysteresis was more likely to occur. In contrast, at the far end of the watershed outlet or the river channel, high values of KSCI were distributed, and anticlockwise hysteresis was more likely to occur. Our findings further enrich the theory of soil erosion and the runoff-sediment relationship at the watershed scale in karst areas, and serve as valuable decision-making references for integrated water and soil sources management.
Albania is situated in the western part of Balkan Peninsula, on the eastern coast of the Adriatic and the Ionian Sea, which is one of the most water−rich regions of the world. The karst landscape in ...Albania covers about 2750 km
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consisting of nearly 24% of the countries territory. Karstic aquifers are the richest in the country. The total renewable karst water resources represent about 80% of the groundwater resources of Albania and nearly 80% of the population of the cities, including the capital Tirana, are supplied by karst water, and important resource is used for the production of the electricity. The sustainable management of karst water resource is difficult due to the high heterogeneity of karst aquifers in terms of type and development of hydraulic porosity, flow velocities, hydraulic head, recharge type and quantity, karst water quality, as well as to the high vulnerability to the human impact.
Márton Veress was born on February 7, 1946 in Szombathely, Hungary. He graduated from the József Attila University as a teacher of Biology and Geography. He became the doctor of Hungarian Academy of ...Sciences in 2004. He has been active in karst research since the mid-1970s, where his main research area was karst morphology, including the study of covered karsts and karren. He received various awards and prizes, including the Knight’s Cross of the Order of Merit of the Republic of Hungary in 2009, and the title of Professor Emeritus in 2016. The semi-structured interview was conducted in February 2023 at the ELTE Savaria University Centre. The purpose of this conversation is to gain a better understanding of the important moments in the professor’s life, and of the milieu that played a role in shaping his professional career. The interview also aims to present the virtues, challenges and tasks of Hungarian geography through the experiences of this article.
Karst ecosystem services (ES) are a key component of terrestrial ES in the world. Karst rocky desertification is one of the biggest ecological and environmental challenges in China. The Karst Rocky ...Desertification Project (RDPs) help to promote land use and land cover and management practices, which aimed to alter the supply of ecosystem services and affect the well-being of both humanity and nature to alleviate ecological degradation and ameliorate regional poverty in southwest China. The spatial aggregation and distribution of ecosystem services is a wise evaluation of ecosystem management and landscape planning. The ecological efficiency of KRD restoration control measures on a regional scale can be explored by ecosystem services bundles. Our study takes the Huajiang-Guangling karst plateau-valley experimental site—a core area implementing ecological restoration projects in Guizhou province, China—as a case study. Nine ESs (e.g. soil conservation, habitat quality, carbon sequestration, etc.) were quantified using different models of InVEST. A self-organizing map (SOM) approach is used to define and map the ESB. The results showed that (1) the overall trend of rocky desertification has improved during the study period, especially in the mild and potential rocky desertification areas. (2) The ESs has improved, particularly agricultural provisioning services and soil conservation, habitat quality, and carbon sequestration. (3) There is a stable synergy relationship between provisioning services and most regulatory services, while the trade effects between ESs are weakened, indicating a subtle functional interdependence between ESs. (4) The changes of bundling patterns showed that the change of ES bundle can promote the transfers of several ESs supply and regulation services in a different project promoting periods. This study provides a new perspective for inspecting the interactions between multiple ESs at the small regional ecological scale. And these results provide an important scientific basis for ecological restoration and reconstruction in karst areas, which are of great significance for improving policy responses and ecosystem management.
•Studied karst systems are hydraulically linked to the hosting karst aquifers.•The greatest event sensitivity observed during autumn and snowless winter periods.•A typical water year with a snowmelt ...spring flood showed ambiguous CCF response.•Flat topography and shallow vadose zone contribute to complex baseflow interaction.•Matrix-conduit gradient inversion occurs during high flow events.
In Estonia, karst aquifers supply roughly a third of annually abstracted domestic groundwater. Karst systems recharged by allogenic humic-rich streams originating from mire-dominated watersheds are common in Lower Estonia (lowlands). This study aimed to characterize the hydrology and hydraulics of two binary lowland karst systems: Salajõe (SKS) and Tuhala karst system (TKS), and their interaction with the hosting karst aquifer. High-resolution water level, discharge, specific conductance time series data combined with tracer test results were analyzed to assess the two systems. The temporal effect of evapotranspiration, snow deposition and snowmelt floods contributed to the variability in recharge event sensitivity of studied watersheds and aquifers, resulting in time-varying CCF strength between precipitation and discharge. The greatest event sensitivity was observed during the autumn and snowless winter seasons. The celerity and solute transport were the greatest in the preferential flow paths of both karst systems, however, solute transport characteristics varied significantly because of differences in structure and maturity of karst porosity. While the dilute allogenic recharge flushed the karst systems occasionally, the contribution of high-SEC groundwater baseflow was significant. During flood events, the matrix-conduit hydraulic gradient could be inverted, resulting in dilute floodwater being pushed into the hosting aquifer from the karst system.
This study includes a general description of the Earth’s karst types based on literary data and field observations. An improved classification of karst types distinguishes the main group, group, and ...subgroup; and, a division of karst types involves a main karst type, karst type, subtype, variety, and non-individual karst type. The relation between karst type and karst area is described. The role of various characteristics of karsts in the development of primary, secondary, and tertiary karst types is analyzed. Their structure is studied, which includes a geomorphic agent, process, feature, feature assemblage, karst system and the characteristics of the bearing karst area. Dominant, tributary, and accessory features are distinguished. The conditions of the stability and the development of types are studied, transformation ways are classified, and the effect of climate on types is described.
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