Large Karst Aquifer Research Articles

The first record of a stygobiotic form of Garra rufa (Heckel, 1843), sympatric with Garra tashanensis Mousavi-Sabet, Vatandoust, Fatemi & Eagderi, 2016 (Teleostei, Cyprinidae), in Iranian subterranean waters

We report the first finding of the stygobiotic form of the cyprinid fish Garra rufa (Heckel, 1843), discovered in a single locality in southwestern Iran, while the epigean form of the species is widely distributed in western Asia (Iran, Jordan, Lebanon, Turkey, and Syria). We also report a new locality for its hypogean congener, Garra tashanensis, about 5 km east of its type locality. The two species occur in syntopy in outflows of the Tang-e-Ban, a seasonal karstic spring that only has flowing water during winter and spring, when fish individuals are washed from the cave to the surface. Identification of the investigated samples was confirmed by morphological analyses, COI distances, and a phylogenetic tree. These findings suggest the existence of a large karst aquifer in the Tashan area that harbours several cave species of fish, crustaceans, and gastropods and may have considerable conservation implications.

Investigation of transport properties and characteristics of a large karst aquifer system in southern China using correlation, spectral, and wavelet analyses

Karst aquifers are highly heterogeneous, and non-stationary systems in terms of hydrodynamic properties. The investigation of the different transport properties and characteristics of a karst aquifer system (KAS) is of great significance for the management and protection of karst aquifers. To investigate the response of discharge (Q), suspended sediment (SS), and temperature (T) to the precipitation (P), we performed correlation, spectral, and wavelet analyses on the hydrologic time series that included mean daily value from 2009/1/1 to 2015/12/31 from the Nandong underground river system (NURS), a large (> 1600 km2) karst-groundwater basin in southern China. The long memory effects can be determined from the autocorrelation functions of the Q, SS and T implied that the NURS has a significant amount of storage. The sharp and narrow cross-correlation function (CCF) peaks and the cross-wavelet transform (XT) power spectrum of the SS vs. P indicated that the response of the SS to P was shorter than that of the Q and T, and also indicated that the weak memory effect and small inertia of the karst systems with regard to SS. The CCF and XT power spectrum indicated that an increase in Q was the main factor triggering the increase in SS, not precipitation, which is contrary to results determined for other karst springs. Furthermore, the XT and cross-wavelet coherence (TC) of T vs. the air temperature (Ta) was used to demonstrate that Ta is not a direct control on the T in the NURS, which can be misinterpreted when using the traditional correlation and spectral analyses.

Mixing processes of autogenic and allogenic waters in a large karst aquifer on the edge of a sedimentary basin (Causses du Quercy, France)

On the edge of sedimentary basins, karst aquifers can be fed by several water origins from both autogenic and allogenic recharge. In some cases, water origin assessment is difficult and issues in water management may arise. The main goal of this study is to understand what controls hydrodynamical and geochemical variations at the outflow of a quite complex and large karst system. More precisely, this study illustrates how a consistent observational setup can be developed, based on a multi-proxy approach that can be used for tracing water origins, evaluating mixing phenomena, and contributions in karst aquifers considering both autogenic and allogenic recharge.The Ouysse karst system (650 km2), located in western France, provides the opportunity of studying water-mixing processes in binary karst systems fed by allogenic and autogenic recharges. Global water chemistry, hydrograph and chemograph analysis during a flood event, and source-mixing calculation were used to evaluate groundwater-flow origins and the contribution of each water type during the studied flood event: (i) karstic water; (ii) evaporite water; (iii) water from igneous-metamorphic rock aquifers.In terms of resource management, the information obtained can be used as a basis of forecasting and management actions.

Mg2+-Based Method for the Pertuso Spring Discharge Evaluation

This paper deals with the Environmental Monitoring Plan concerning the catchment work project of the Pertuso karst spring, which is going to be exploited to supply an important drinking water network in the south part of Roma district. The Pertuso Spring, located in the Upper Valley of the Aniene River, is the main outlet of a large karst aquifer, which is one of the most important water resources in the southeast part of Latium Region, Central Italy, used for drinking, agriculture, and hydroelectric supplies. The environmental monitoring activities provided data about one spring and two cross-sections of the Aniene River, from July 2014 to May 2016. A combined approach based on discharge measurements and hydrogeochemical analysis has been used to study flow paths and groundwater–surface water interaction in the study area. Tracer methods are particularly suitable in hydrogeological studies to assess transit times and flow properties in karst aquifers. The analysis of solute contents in the sampling points brought forth the identification of the Mg2+ ion as a conservative tracer in this specific system and, consequently, to the development of a conceptual model based on chemical mass balance for the Pertuso Spring discharge evaluation.

A proposal of conceptual model for Pertuso Spring discharge evaluation in the Upper Valley of Aniene River

The Upper Aniene River basin is part of a large karst aquifer, which interacts with the river, and represents the most important water resource in the southeast part of Latium Region, Central Italy, used for drinking, agriculture and hydroelectric supplies. This work provides hydrogeochemical data and their interpretations for 1 spring and 2 cross section of Aniene River, monitored from July 2014 to December 2015, in the Upper Valley of Aniene River, to identify flow paths and hydrogeochemical processes governing groundwater-surface water interactions in this region. These activities deal with the Environmental Monitoring Plan made for the catchment work project of the Pertuso Spring, in the Upper Valley of Aniene River, which is going to be exploited to supply an important drinking water network in the South part of Rome district. Discharge measurements and hydrogeochemical data were analyzed to develop a conceptual model of aquifer-river interaction, with the aim of achieving proper management and protection of this important hydrogeological system. All groundwater samples are characterized as Ca-HCO3 type. Geochemical modeling and saturation index computation of the water samples show that groundwater and surface water chemistry in the study area was evolved through the interaction with carbonate minerals. All groundwater samples were undersaturated with respect to calcite and dolomite, however some of the Aniene River samples were saturated with respect to dolomite. The analysis of Mg2+/Ca2+ ratios indicates that the dissolution of carbonate minerals is important for groundwater and surface water chemistry, depending on the hydrological processes, which control the groundwater residence time and chemical equilibria in the aquifer.

The Origine and Evolution of Coastal and Submarine Springs in Bakar Bay

Članek obravnava obalne in podmorske izvire v Bakarskem zalivu. Največ izvirov je ob severovzhodni obali zaliva, kjer je najnižji del kontakta med kraškim vodonosnikom in flišem, ki predstavlja hidrogeološko bariero. Študijsko območje obsega obalo med Črnim in Žminjco, kjer voda izteka koncentrirano v nizu kraških izvirov in difuzno na večih območjih. Ob dvigu morske gladine ob koncu pleistocena so nekateri obalni izviri prešli pod gladino, pojavili pa so se tudi novi, višji izviri. Veliko podmorskih izvirov ni poznanih, vendar na njihov obstoj kaže študija vodne bilance. Zaradi velikega hidravličnega gradienta veliko podmorskih izvirov deluje kot vrulje. Mešanje morske in sladke vode v hidravlično nestabilnem območju je vzrok, da je voda iz teh izvirov po večini brakična.The paper presents coastal and submarine springs in Bakar Bay. The northeastern coast of Bakar Bay is abound in springs, since there is the lowest placed contact between large karst aquifer and flysch lithogenetic complex which forms hydrogeological barrier. Studied area is situated between Črno and Žminjca locations, where water flows out in series of concentrated coastal and submarine springs as well as on the places of a diffuse outflow. A rapid raise of sea-level from the end of the Pleistocene changed the hydrogeological conditions so that coastal springs were submerged and new ones, at higher levels appeared. Some of submerged springs continued to throw out water, that is, they started to function as submarine springs (vrulja) due to a strong inflow from the background and high pressures. Some of them were not registered, although according to water balance analyses of wider area, widespread evidences of groundwater outflow could be expected. Their position reflects geological fabric of the area. Groundwaters have intensive flowing gradient. Their flowing out in hydraulically unstable zone have facilitated mixing of sea- water and fresh-water and as a result spring-water is usually brackish.

Record of predation on the bat Rhinopoma microphyllum (Chiroptera: Rhinopomatidae) by the Spalerosophis microlepis (Reptilia: Colubridae), in western Iran

of the Zagros Range in vicinity of the northern Mesopotamian plain at the border of Iran and Iraq. This cave is a part of several large cavities created as a result of collapse in a karst formation. This collapse has exposed a large karst aquifer and two adjacent deep caves. The caves are about 100 meters away from a small village with the same name. The area around the caves is extensively altered for agriculture purposes and almost nothing is left from the natural vegetation cover except in the depth of high valleys. The weather condition in this area is characterized by a hot and dry summer and a winter with no freezing period. Although average annual precipitation in this area is around 300 mm most of this comes as winter or early spring rains. As a result, very few permanent streams and rivers are present in this area. In lowlands of the Mesopotamian plain summer is hot and average maximum temperature in July may approach to 50oC. However, in some areas where the Mesopotamian plain meets the Zagros range too abruptly a rapid environmental gradient appears as a result of interaction of the cold and wet climatic system from the highlands of the Iranian plateau and the hot and dry climate regime from the northern Mesopotamian plain.

Contribution of correlation and spectral analyses to the regional study of a large karst aquifer (Charente, France)

The purpose of the study is to demonstrate that correlation and spectral analyses can contribute to the regional study of a large karst aquifer. An example is presented for the La Rochefoucauld karst aquifer (Charente, France). Different types of spatially distributed time series provide valuable spatio-temporal information for the karst aquifer. The available time series consist of the spring flow rates, the flow rates at different locations in sinking streams, the piezometric levels, the electrical conductivity and temperature of the water, the atmospheric pressure and the precipitation. The analysis of the flow rates at the springs shows that the aquifer empties very slowly and has a large storage capacity. Hydrodynamic links were established between three of the four rivers flowing on the aquifer and the springs. The results also demonstrate the important spatial heterogeneity of the aquifer and indicate that the most rapid flow occurs in the northern part of the aquifer. Hourly piezometric and electrical conductivity time series indicate that the transmissivity of the aquifer varies when some conductive channels become desaturated during the low water period. The delays between the distributed recharge and the piezometric level, between the localized river input and the flow rates at the springs and between the electrical conductivities in rivers and the main spring provide information on the travel times in the aquifer. The observation of earth tides and barometric effects indicate that this apparently unconfined aquifer has a confined behaviour.