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 ◽  
...  

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.

Author(s):  
Henghua Zhu ◽  
Jianwei Zhou ◽  
Zhizheng Liu ◽  
Lizhi Yang ◽  
Yunde Liu

The study of the hydrochemical characteristics and the water–rock interaction of karst groundwater is very important for the rational exploitation of karst groundwater and its pollution control. In this paper, the systematic clustering method was used to analyze the hydrochemical characteristics of different types of groundwater, combined with hydrochemical graphic analysis and correlation analysis to explore the impact of chemical acidic wastewater on the evolution of karst aquifer in the Dawu water source area, northern China. The results show that the chemical acid wastewater, sourcing from discharges/spillages from the local chemical industries, has different degrees of pollution impact on karst groundwater, causing the total hardness of all karst groundwater and the total dissolved solids, Cl− and SO42− in nearly half of the karst groundwater to exceed the quality indexes of class III water in China’s standard for groundwater quality (GB/T 14848-2017). Hydrochloric acid and sulfuric acid in the wastewater can be buffered by the dissolution of carbonate rocks, resulting in a nearly neutral pH (pH-buffering effect) and an increase in Ca2+, Mg2+, Sr, Cl− and SO42− concentrations in karst groundwater.


Water ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 93
Author(s):  
Francesco Maria De Filippi ◽  
Silvia Iacurto ◽  
Gerardo Grelle ◽  
Giuseppe Sappa

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.


2011 ◽  
Vol 1 (1) ◽  
pp. 47-56 ◽  
Author(s):  
Yonghong Hao ◽  
Yajie Wang ◽  
Jiaojuan Zhao ◽  
Huamin Li

Author(s):  
Wei Chang ◽  
Junwei Wan ◽  
Jiahua Tan ◽  
Zongxing Wang ◽  
Cong Jiang ◽  
...  

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.


2019 ◽  
Vol 20 (10) ◽  
pp. 2057-2068 ◽  
Author(s):  
Lixing An ◽  
Xingyuan Ren ◽  
Yonghong Hao ◽  
Tian-Chyi Jim Yeh ◽  
Baoju Zhang

Abstract In karst terrains, fractures and conduits often occur in clusters, forming groundwater quick flow belts, which are the major passages of groundwater and solute transport. We propose a cost-effective method that utilizes precipitation and spring discharge data to identify groundwater quick flow belts by the multitaper method (MTM). In this paper, hydrological processes were regarded as the transformation of precipitation signals to spring discharge signals in a karst spring catchment. During the processes, karst aquifers played the role of signal filters. Only those signals with high energy could penetrate through aquifers and reflect in the spring discharge, while other weak signals were filtered out or altered by aquifers. Hence, MTM was applied to detect and reconstruct the signals that penetrate through aquifers. Subsequently, by analyzing the reconstructed signals of precipitation with those of spring discharge, we acquired the hydraulic response time and identified the quick flow belts. Finally, the methods were applied to the Niangziguan Spring (NS) catchment, China. Results showed that the hydraulic response time of the spring discharge to precipitation was 3 months at Pingding County; 4 months at Yuxian County, Yangquan City, Xiyang County, and Heshun County; and 27 months at Shouyang County and Zouquan County. These results suggested that Pingding County is located at a groundwater quick flow belt, which is a major passage of groundwater and contaminants, in the NS catchment. This is important since Pingding County is not only the key development area of karst groundwater but also the key conservation area for sustainable development of karst groundwater resources in NS catchment.


Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 985 ◽  
Author(s):  
Viet-Ha Nhu ◽  
Omid Rahmati ◽  
Fatemeh Falah ◽  
Saeed Shojaei ◽  
Nadhir Al-Ansari ◽  
...  

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.


Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1189
Author(s):  
Malihe Shirafkan ◽  
Zargham Mohammadi ◽  
Vianney Sivelle ◽  
David Labat

In this study, a synthetic modeling approach is proposed to quantify the effect of the amount and direction of the exchange flow on the karstic spring discharge fluctuations under different hydrologic conditions corresponding to high and low flow conditions. We hypothesis that the spring discharge fluctuations constitute a valuable proxy to understand the internal processes of the karst system. An ensemble of spring hydrographs was synthetically produced to highlight the effect of exchange flow by exploring the plausible range of variability of coefficients of exchange flow, conduit diameter, and matrix hydraulic conductivity. Moreover, the change of the rate of point recharge through the karst conduit allows for the quantifying of the sensibility of the spring hydrograph to the directions of exchange flow. We show that increasing the point recharge lies to a remarkable linear recession coefficient (β) as an indication of the conduit flow regime. However, a reduction in and/or lack of the point recharge caused the recession coefficient to change to exponential (α) due to the dominant effect of the matrix restrained flow regime and/or conduit-influenced flow regime. The simulations highlight that the exchange flow process from the conduit to the matrix occurred in a short period and over a restricted part of the conduit flow regime (CFR). Conversely, the exchange flow dumped from the matrix to the conduit occurs as a long-term process. A conceptual model is introduced to compare spring hydrographs’ characteristics (i.e., the peak discharge, the volume of baseflow, and the slope of the recession curve) under the various flow conditions with the directions of the exchange flow between the conduit and the matrix.


Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2775
Author(s):  
Vladimir Živanović ◽  
Nebojša Atanacković ◽  
Saša Stojadinović

The application of groundwater vulnerability methods has great importance for the sanitary protection zones delineation of karstic sources. Source vulnerability assessment of karst groundwater has mainly relied on the European approach (European Cooperation in Science and Technology—COST action 620), which includes analysis of the K factor, which refers to water flow through the saturated zone of the karst system. In the paper, two approaches to groundwater vulnerability assessment have been applied, COP + K and TDM (Time-Dependent Model) methods, to produce the most suitable source vulnerability map that can be transformed into sanitary protection zones maps. Both methods were tested on the case example of Blederija karst spring in Eastern Serbia. This spring represents a classical karst spring with allogenic and autogenic recharge. Dual aquifer recharge points out the necessity for the inclusion of the vulnerability assessment method created especially for the assessment of karst groundwater. Obtained vulnerability maps show similar results, particularly in the spring and the ponor areas, and these zones are most important for future protection. The COP + K method brings out three vulnerability classes that can be directly transformed into three sanitary protection zones. Contrary to the previous one, the TDM method uses water travel time as a vulnerability degree. The results show that the final map can be easily used to define sanitary zones considering different national legislation.


Geosciences ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 15 ◽  
Author(s):  
Antonios Manakos ◽  
Maria Ntona ◽  
Nerantzis Kazakis ◽  
Konstantinos Chalikakis

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.


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