scholarly journals Magnesium as Environmental Tracer for Karst Spring Baseflow/Overflow Assessment—A Case Study of the Pertuso Karst Spring (Latium Region, Italy)

Water ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 93
Author(s):  
Francesco Maria De Filippi ◽  
Silvia Iacurto ◽  
Gerardo Grelle ◽  
Giuseppe Sappa
Keyword(s):  
Linear Relationship ◽  
Karst Aquifer ◽  
Central Italy ◽  
Sensitivity Analyses ◽  
Magnesium Concentration ◽  
Spring Discharge ◽  
Storm Events ◽  
Karst Spring ◽  
Diffuse Flow ◽  
Two Samples

Following a previous research carried out on the same site, this paper presents the update of the Mg2+ based method for the estimation of Pertuso Spring discharge, located in Central Italy. New collected data confirmed the validity of the proposed model and the conservative behaviour of Mg2+ for groundwater related to the Pertuso Spring aquifer. Further analysis allowed to obtain a local linear relationship between magnesium concentration and total spring discharge (including exploitation rate), regardless of the mixing model proposed with the Aniene River. As regards two samples which fall out of the linear relationship and could have been detected as “outliers”, more in-depth data processing and sensitivity analyses revealed that the lowering in magnesium, at equal discharges, is determined by the appearance of the quick-flow component, less mineralized and related to storm events. Results showed that under specific conditions, related to the absence or presence of previous intense rainfall events, Mg2+ could be effectively a useful tracer for separating spring conduit flow (overflow) from diffuse flow (baseflow) within the karst aquifer.

scholarly journals Impacts of Artificial Regulation on Karst Spring Hydrograph in Northern China: Laboratory Study and Numerical Simulations

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 755 ◽  
Author(s):  
Wu ◽  
Shu ◽  
Li ◽  
Chen ◽  
Xu ◽  
...  
Keyword(s):  
Karst Aquifer ◽  
Time Lag ◽  
Northern China ◽  
Flow Fields ◽  
Spring Discharge ◽  
Karst Groundwater ◽  
Karst Spring ◽  
Stagnation Points ◽  
Recession Coefficient ◽  
Laboratory Tank

Karst aquifers produce the world’s largest springs and supply the water resources to about a quarter of the global population while being influenced by high-intensity human activities. Knowledge about spring discharge hydrographs driven by the effects of artificial regulation is essential to develop practical strategies for the management of karst groundwater. Based on hydrogeological conditions of the karst aquifer in Jinan, a two-dimensional laboratory tank was constructed, and a corresponding numerical simulation model was developed to explore how artificial regulation drives spring hydrographs in northern China. The results showed that the spring hydrographs were significantly changed under the effects of artificial regulation. The recession coefficient increased with pumping and decreased with increasing injection rates. The late sub-recession of spring discharge did not obey the exponential recession under the influence of injection. Pumping and injection in conduit zones showed more obvious effects on the recession coefficient in the late sub-recession curves. Groundwater exchange between conduits and fissure zones differed totally for different artificial regulation modes. With continuing rainfall, the flow fields were gradually controlled by rainfall. There was a time lag in the flow fields caused by rainfall. Under the stress of exploitation at different positions, stagnation points appeared at different locations in fissure zones, and locations of stagnation points were highly dependent on the positions of pumping wells. These findings are essential for better management of karst groundwater and karst spring protection.

scholarly journals Responses of Spring Discharge to Different Rainfall Events for Single-Conduit Karst Aquifers in Western Hunan Province, China

2021 ◽  
Vol 18 (11) ◽  
pp. 5775
Author(s):  
Wei Chang ◽  
Junwei Wan ◽  
Jiahua Tan ◽  
Zongxing Wang ◽  
Cong Jiang ◽  
...  
Keyword(s):  
Water Resource Management ◽  
Complex Structure ◽  
Karst Aquifer ◽  
Hunan Province ◽  
Spring Discharge ◽  
Karst Aquifers ◽  
Karst Spring ◽  
Rainfall Events ◽  
Hydrogeological Characteristics ◽  
Western Hunan

It is a challenge to describe the hydrogeological characteristics of karst aquifers due to the complex structure with extremely high heterogeneity. As the response of karst aquifers to rainfall events, spring discharge variations after precipitation can be used to identify the internal structure of karst systems. In this study, responses of spring discharge to different kinds of precipitations are investigated by continuously monitoring precipitation and karst spring flow at a single-conduit karst aquifer in western Hunan province, China. Recession curves were used to analyze hydrodynamic behaviors and separate recession stages. The results show that the shape of the recession curve was changed under different rainfall conditions. Recession processes can be divided in to three recession stages under heavy rain conditions due to water drainage mainly from conduits, fracture, and matrix at each stage, but only one recession stage representing drainage mainly from matrix in the case of light rain. With the change in amount and intensity of precipitation, the calculated recession coefficient at each stage changes in an order of magnitude. The influence of precipitation on the recharge coefficient and the discharge composition at each recession are discussed, and then the conceptual model diagram of water filling and releasing in the single-conduit karst aquifers is concluded. The findings provide more insight understand on hydraulic behaviors of karst spring under different types of rainfall events and provide support for water resource management in karst regions.

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

2016 ◽  
Author(s):  
Giuseppe Sappa ◽  
Flavia Ferranti ◽  
Francesco Maria De Filippi
Keyword(s):  
Surface Water ◽  
Water Chemistry ◽  
Conceptual Model ◽  
Saturation Index ◽  
Karst Aquifer ◽  
Central Italy ◽  
Spring Discharge ◽  
Carbonate Minerals ◽  
Surface Water Chemistry ◽  
Groundwater Samples

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.

scholarly journals Mapping of Groundwater Spring Potential in Karst Aquifer System Using Novel Ensemble Bivariate and Multivariate Models

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 985 ◽  
Author(s):  
Viet-Ha Nhu ◽  
Omid Rahmati ◽  
Fatemeh Falah ◽  
Saeed Shojaei ◽  
Nadhir Al-Ansari ◽  
...  
Keyword(s):  
Characteristic Curve ◽  
Karst Aquifer ◽  
Groundwater Potential ◽  
Spring Discharge ◽  
Arid Environments ◽  
Calibration Data ◽  
Karst Spring ◽  
Karst Springs ◽  
Ensemble Modelling ◽  
Aquifer System

Groundwater is an important natural resource in arid and semi-arid environments, where discharge from karst springs is utilized as the principal water supply for human use. The occurrence of karst springs over large areas is often poorly documented, and interpolation strategies are often utilized to map the distribution and discharge potential of springs. This study develops a novel method to delineate karst spring zones on the basis of various hydrogeological factors. A case study of the Bojnourd Region, Iran, where spring discharge measurements are available for 359 sites, is used to demonstrate application of the new approach. Spatial mapping is achieved using ensemble modelling, which is based on certainty factors (CF) and logistic regression (LR). Maps of the CF and LR components of groundwater potential were generated individually, and then, combined to prepare an ensemble map of the study area. The accuracy (A) of the ensemble map was then assessed using area under the receiver operating characteristic curve. Results of this analysis show that LR (A = 78%) outperformed CF (A = 67%) in terms of the comparison between model predictions and known occurrences of karst springs (i.e., calibration data). However, combining the CF and LR results through ensemble modelling produced superior accuracy (A = 85%) in terms of spring potential mapping. By combining CF and LR statistical models through ensemble modelling, weaknesses in CF and LR methods are offset, and therefore, we recommend this ensemble approach for similar karst mapping projects. The methodology developed here offers an efficient method for assessing spring discharge and karst spring potentials over regional scales.

scholarly journals Preliminary chemical characterization of groundwater in the Rome Municipality

2015 ◽  
Author(s):  
Luca Pizzino ◽  
Daniele Cinti ◽  
Monia Procesi ◽  
Alessandra Sciarra
Keyword(s):  
Chemical Elements ◽  
Central Italy ◽  
Chemical Characterization ◽  
Mineral Waters ◽  
Measured Temperature ◽  
Large Variability ◽  
Rock Interaction ◽  
Interaction Processes ◽  
Two Samples ◽  
Water Rock Interaction

In summer 2015 a geochemical survey on groundwater was carried out at 31 sampling points (wells and piezometers) belonging to the new “Official monitoring groundwater network of Rome Municipality” (GMNR). The following parameters were measured: temperature, pH, electrical conductivity (i.e. salinity) and alkalinity; these data were used to compute partial pressure of CO2 (pCO2). Furthermore, samples were collected to characterise waters from a chemical point of view (major elements). To implement our data - base, chemical analyses of 6 CO2 - rich mineral waters of Rome were considered. Hydrochemical survey was mainly devoted to: i) classify waters in chemical facies; ii) investigate the main water-rock interaction processes governing the water’s chemical evolution, also affected by variable amounts of dissolved CO2 and iii) define the pCO2 level in groundwater in the frame of the knowledge so far acquired in the Tyrrhenian sector of central Italy.. Groundwater shows a dominant Ca-HCO3 chemistry; some samples belong to Na-HCO3, Na-Cl and CaCl2 hydrochemical facies. In the dominant facies waters show a large variability in the abundance of chemical elements, in their salinity (ranging between 0.46 e 3.83 g/l) and pH (in the interval 5.87-7.22); these features are mainly due to different water-rock interaction processes together with the presence of variable CO2 contents. Na-HCO3 waters show the lowest salinity values (TDS up to 0.32 g/l) and strongly alkaline pH; cation exchange processes with clays, causing Na enrichment and Ca and Mg removal from solution, can be invoked to justify the observed chemistry. Waters of the Castel Fusano Natural Reserve (CFNR) belong to the Na-Cl and Ca-Cl2 facies; the different chemistry reflects the geochemical processes going on in the considered coastal aquifers such as: i) mixing between freshwater and saline waters of marine origin (fossil waters, seawater intrusion) and ii) cationic exchanges with clays that make up the less permeable sediments of the area. Two samples of the CFNR group have Ca-HCO3 chemistry and represent aquifers not affected by salinization processes. Calculated pCO2 distribution is highly variable, from low (0.03 bar) to high values (0.72 bar), implying different CO2 input (and origin) in the studied aquifers. Highest levels of carbon dioxide are linked to the degassing processes going on in the Tyrrhenian sector of Central Italy.

scholarly journals Enhanced Characterization of the Krania–Elassona Structure and Functioning Allogenic Karst Aquifer in Central Greece

Geosciences ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 15 ◽  
Author(s):  
Antonios Manakos ◽  
Maria Ntona ◽  
Nerantzis Kazakis ◽  
Konstantinos Chalikakis
Keyword(s):  
Conceptual Model ◽  
Moving Average ◽  
Karst Aquifer ◽  
Groundwater Vulnerability ◽  
Spring Water ◽  
Geological Mapping ◽  
Spring Discharge ◽  
Water Type ◽  
Central Greece

The present study highlights the importance of geological, hydrogeological, and hydrogeochemical characterization of a karst aquifer in building a conceptual model of the system. The karst system of Krania–Elassona in central Greece was chosen for this application. Hydrogeological research included geological mapping and hydrogeological analysis. Additionally, hydrochemical analysis of water samples was performed in boreholes, rivers, and the system’s main spring. The Krania–Elassona aquifer consists of three horizons of marbles and is characterized by mature karstification. The karst aquifer is characterized by allogenic recharge mainly from the River Deskatis that accounts for up to 92% of the total flow. Groundwater and spring water are generally characterized as good quality and are suitable for irrigation and domestic use. The water type of the spring water is classified as Mg-HCO3. The application of a SARIMA (Seasonal Autoregressive Integrated Moving Average Model) model verified the conceptual model and successfully simulated spring discharge for a two-year period. The results of this study highlight the importance of basic hydrogeological research and the initial conceptualization of karst systems in reliably assessing groundwater vulnerability and modeling.

scholarly journals Recharge Impulse Spreading in Western Carpathian’s Mountainous Fissure–Karst Aquifer

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 763 ◽  
Author(s):  
Malík ◽  
Coplák ◽  
Kuvik ◽  
Švasta
Keyword(s):  
Water Temperature ◽  
Karst Aquifer ◽  
Large Body ◽  
Vertical Component ◽  
Groundwater Table ◽  
Time Shift ◽  
Winter Period ◽  
Time Interval ◽  
Spring Discharge ◽  
Groundwater Flux

: Foreseen construction of a highway tunnel in the northern part of the Veľká Fatra Mts. (Slovakia) triggered the need for extensive hydrogeological investigations. The projected tunnel axis would cut through a large body buildup of Middle Triassic carbonate rocks. Dolomites and limestones with fissure–karstic permeability are surrounded by less-permeable marls, so that all springs dewatering this uplifted plate of carbonates are found above the erosion base on its edges. Detailed, hourly-based discharge monitoring of all four major springs was performed during the spring and summer period of 2014. In the meantime, groundwater table observations in two boreholes, located in the center of the fissure–karst aquifer, were run in the same time interval. Based on air temperature and precipitation records, the 2013–2014 winter period was practically without snow cover. In the middle of March 2014, an intense rainfall event caused a sudden rise of the groundwater table in the TK-04 borehole located in the southern part of the carbonate plate. Spreading of this singular hydraulic impulse throughout the structure was differently registered at individual springs within the time shift span of 1.38 to 65.25 days. Groundwater level rise of 0.40 m in the TK-04 borehole was postponed in 5.33 days. The response time of spring discharge to sudden groundwater table rise within the structure occurred later at springs with a higher water temperature. Water temperature differences between individual springs were still within the 2.46 °C narrow interval (5.57–8.03 °C). The vertical component of groundwater flux should play an important role even in a relatively simple, plate-shaped mountainous karstic aquifer fully uplifted above the erosional base, as was the case of the investigated Kopa Mt. hydrogeological structure.

scholarly journals The possible negative consequences of underground dam and reservoir construction and operation in coastal karst areas: an example of the hydro-electric power plant (HEPP) Ombla near Dubrovnik (Croatia)

2013 ◽  
Vol 13 (8) ◽  
pp. 2041-2052 ◽  
Author(s):  
T. Roje-Bonacci ◽  
O. Bonacci
Keyword(s):  
Power Plant ◽  
Electric Power ◽  
Karst Aquifer ◽  
Grout Curtain ◽  
Negative Consequences ◽  
Karst Spring ◽  
Coastal Karst ◽  
Underground Dam ◽  
The Mean ◽  
Annual Discharge

Abstract. The Ombla Spring represents a typical abundant coastal karst spring located in the vicinity of the town of Dubrovnik (Croatia). Its outlet is at an altitude of 2.5 m above sea level (m a.s.l.) and the water from it immediately flows into the Adriatic Sea. The minimum and maximum measured discharges are 3.96 m3 s−1 and 117 m3 s−1, respectively. The Trebišnjica River traverses through its catchment. The mean annual discharge, after the canalization of over 60 km of its watercourse with spray concrete (in the time span 1981–2011), is 24.05 m3 s−1. Before massive civil engineering work which took place during 1968–1980, the mean annual discharge was 28.35 m3 s−1. There is a project for construction of the hydro-electric power plant (HEPP) Ombla, which will exclusively use groundwater from the Ombla Spring karst aquifer. The underground dam will be constructed about 200 m behind the existing karst spring outflow in the karst massif, by injecting a grout curtain. The top of the grout curtain is planned to be at an altitude of 130 m a.s.l. This karst system is complex, sensitive, vulnerable and ecologically extremely valuable. The grout curtain, as well as the HEPP Ombla development, could lead to extremely dangerous technical and environmental consequences. In this paper some probable, negative consequences of the HEPP Ombla construction and development are explained. The HEPP Ombla could result in many large and hard-to-predict negative consequences which are specific for this particular HEPP, for example (1) severe spring discharge change; (2) unpredictable regional groundwater redistribution; (3) threatening of endemic fauna; (4) induced seismicity; (5) induced sinkholes; (6) occurrence of landslides; (7) conflict regarding internationally shared karst aquifers; (8) intensification of karst flash floods; (9) sea water intrusion in coastal karst aquifer; etc.

Quantification of karst aquifer discharge components during storm events through end-member mixing analysis using natural chemistry and stable isotopes as tracers

2006 ◽  
Vol 14 (7) ◽  
pp. 1171-1191 ◽  
Author(s):  
Daniel H. Doctor ◽  
E. Calvin Alexander ◽  
Metka Petrič ◽  
Janja Kogovšek ◽  
Janko Urbanc ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Karst Aquifer ◽  
Storm Events
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