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 Quantitative and Qualitative Methods for the Characterization of Karst Springs (case study: Lorestan province, Zagros Mountain, Iran)

2022 ◽  
Author(s):  
Fatemeh Geravand ◽  
Seiyed Mossa Hosseini ◽  
Mehran Maghsoudi ◽  
Mojtaba Yamani
Keyword(s):  
Groundwater Resources ◽  
Saturation Index ◽  
Karst Aquifer ◽  
Base Flow ◽  
Spring Discharge ◽  
Karst Aquifers ◽  
Zagros Mountains ◽  
Discharge Data ◽  
Karst Springs

Abstract Karst groundwater resources in the Zagros Mountains are vital for supplying of different demands in the region which need to sustainable management and protection. Quantitative and qualitative characterization of karst aquifers in this region were understudied due to lack of site-specific logging-data and speleological investigations. In this study, a state-of-the-art of the statistical methods developed to characterize karst aquifer based on analyses of the spring recession hydrograph and spring water quality are presented. These methods including Manging’s method for classification of karst aquifers, relationships of precipitation and discharge data, groundwater quality index (GQI), hydrochemical diagrams (Piper, Durov and Gibbs), and Saturation index (SI), Chloro-Alkaline indices (CAI). 42 major karst springs mainly located in folded part of Zagros region (western Iran) are selected for application of the reviewed methods. Results indicated that the saturated zone exerts almost main control over the discharge of 76% of the studied springs. The base-flow contributes as between 80.0% to 100% of total water storage in the study aquifers. 78.5% of the studied aquifers have a high karstification degree. An insignificant lag-time is observed between the precipitation on the karst basin and spring discharge. The hydrochemical diagrams show that the waters are dominated by HCO3 and Ca and the majority of the waters are alkaline, with originate from silicate minerals weathering. Such repeatable methods adopted in this study can provide crucial information of the karst aquifers, especially those suffer scarcity of aquifer hydrodynamic data.

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.

Karst springs in small islands: The Kamari spring (Mylopotamos) in Kythira Island, Greece

2020 ◽  
Author(s):  
Nikolaos Karalemas ◽  
Christos Filis ◽  
Emmanuel Skourtsos ◽  
Haralambos Kranis ◽  
Stylianos Lozios ◽  
...  
Keyword(s):  
Water Level ◽  
Karst Aquifer ◽  
Spring Discharge ◽  
Microbiological Analysis ◽  
Recharge Area ◽  
Annual Fluctuation ◽  
Aquifer System ◽  
Aquifer Systems ◽  
Karst Aquifer System ◽  
Carbonate Formations

<p>Three main aquifer systems developed on Kythira Island (Greece) include (Pagounis, 1981; Pagounis & Gertsos, 1984, Danamos, 1991; Koumantakis et al., 2006; Filis et al., 2019):</p><ul><li>The porous aquifer system in Neogene and Quaternary formations.</li> <li>The karst aquifer system in the carbonate formations of the Pindos and Tripolis Units.</li> <li>The aquifer system (both shallow and deep) in the fractured hard rocks mainly of the Phyllites – Quartzites Unit.</li> </ul><p>The main discharge of the aquifer systems takes place in coastal and submarine brackish springs around the island, except for its northern part where the Phyllites – Quartzites Unit outcrops and its central part where springs of small capacity discharge the carbonate formations of the Pindos Unit.</p><p>Precipitation is the direct recharge of the three aforementioned aquifer systems while indirectly lateral discharge occurs in places between adjacent and tangential aquifer systems and from the streams runoff as well.</p><p>In the area of Mylopotamos village four springs discharge the karst aquifer of the Pindos Unit within the channel of Kako Laghadi stream forming downstream the known “Neraida or Fonissa waterfall”. Moreover, along the dell of Kako Laghadi stream 22 watermills were built, among the plane trees and the ivy.</p><p>The most significant of the aforementioned springs is the Kamari spring (+282.28 meters a.s.l.) which emerge at the thrust fault between the overlying permeable carbonates and the underlying impermeable flysch formation of the Pindos Unit. The discharge of the Kamari spring presents annual fluctuation which varies from app. 45-50 m<sup>3</sup>/h (during winter) to total recession (during summer), due to restriction of the precipitation and the prolonged drought and overpumping of its recharge area mainly with boreholes.</p><p>The inactive municipal borehole of Mylopotamos village (+299.15 meters a.s.l.) is located app. 310 meters SSE of the Kamari spring within its recharge area (karst aquifer of the Pindos Unit). This borehole of a total depth of 40 meters penetrates carbonates of the Pindos Unit which thickness exceeds 100 meters in that area. Monthly measurements of the Kamari spring discharge and the water table head in the inactive borehole demonstrate clear and direct hydraulic correlation between them. The Kamari spring presents outflow only in the case when the water level head of the borehole exceeds +282.28 meters. This means that the water level head in the borehole should not exceed 16.87 meters from the earth surface. Taking into account all the aforementioned, the Kamari spring is designated as an overflow spring.</p><p>Finally, microbiological analysis from the Kamari spring showed qualitative degradation, due to human activities in the wider area (Pagounis, 1981; Filis et al., 2019).</p>

scholarly journals BRACKISH KARST SPRINGS SIMULATION WITH “MODKARST” MODEL UNDER NOT ENOUGH DATA CONDITIONS (THE CASE OF THE “POTAMI” SPRING AT HIMARA ALBANIA)

2017 ◽  
Vol 43 (4) ◽  
pp. 1777
Author(s):  
A. Maramathas ◽  
J. Gialamas ◽  
A. Pambuku ◽  
H. Beshku ◽  
E. Vako
Keyword(s):  
Mathematical Model ◽  
Chloride Concentration ◽  
Field Measurements ◽  
Spring Water ◽  
Spring Discharge ◽  
Karst Spring ◽  
Karst Springs ◽  
The Sustainable Development ◽  
Order Of Magnitude ◽  
Energy Balances

A simulation is presented of the operation of a brackish karst spring with the MODKARST deterministic mathematical model under not enough data conditions. MODKARST is a deterministic mathematical model for karst springs, able to accommodate brackish water. It incorporates mass and energy balances in a system of reservoirs properly connected that approximates the karst system and the sea. A complete fitting for this model needs field measurements about spring discharge and spring water chloride concentration at least for a hydrological year. The particular case analysed is the “Potami” brackish karst spring at Himara in Albania. MODKARST simulated the hydrograph along with the variation with time of the chloride concentration. The fitting of the model was based only on chloride concentrations measurements of the spring water that have taken place from 1/5/2007 till 27/12/2007, since there were not spring discharge measurements except for a single one, which simply gave the order of magnitude of this parameter. From the simulation of the model, information was drawn about the recharge area, the effective infiltration coefficient and the dominant seawater intrusion mechanism of the spring. Taking the above information into account, a set of proposals for the sustainable development of the spring was sketched.

scholarly journals Ionic Runoff as a Way to Determine the Degree of Karst Denudation (Case Study Jasov Plateau, Slovak Karst, Slovakia)

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1449
Author(s):  
Alena Gessert ◽  
Imrich Sládek ◽  
Veronika Straková ◽  
Mihály Braun ◽  
Enikő Heim ◽  
...  
Keyword(s):  
Heavy Rain ◽  
Similar Amount ◽  
Karst Water ◽  
Karst Spring ◽  
Snow Melting ◽  
Flow Rates ◽  
Karst Springs ◽  
Degree Of Protection ◽  
Episodic Events

Estimation of the catchment area of a karst spring is not possible in all areas for various reasons. The Slovak Karst is protected by the highest degree of protection and karst springs are used as a source of drinking water for the second largest city in Slovakia, Košice. From this reason, no results on ionic runoff or chemical denudation have been published from this area and the most appropriate way to obtain information about the denudation rate is to determine the ionic runoff. This paper provides an overview of ionic runoff results based on sampling and analysis of karst water from six springs in the period November 2013–October 2016 (three hydrological years) and periodic measurements. Springs have significantly fluctuated flow rates from 0 L/s in summer and autumn up to 192 L/s, and episodic events during the snow melting and heavy rain in the spring of 2013 are also known (more than 380 L/s). The total value of ionic runoff for the area of 40,847 m3/y.km2 is comparable with the Vracanska Plateau in Bulgaria, which lies at a similar altitude and with a similar amount of precipitation.

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