scholarly journals Sustainability of Water Resources in Karst Undermined by Tunneling: A Case Example

2022 ◽  
Vol 14 (2) ◽  
pp. 732
Author(s):  
Drago Dvanajščak ◽  
Jože Ratej ◽  
Vojkan Jovičić
Keyword(s):  
Water Resources ◽  
Karst Aquifer ◽  
Karst Aquifers ◽  
Groundwater Levels ◽  
Karst Environment ◽  
Railway Line ◽  
Variable Porosity ◽  
Site Investigations ◽  
Limestone Rock

Water resources in karsts are scarce due to the high cavernosity in the otherwise low-permeability limestone rock mass. The highly variable porosity and transmissivity of karst aquifers are caused by a network of channels, caverns, and caves that typically act as water-bearing, connected vessels. Tunneling in a karst environment can severely deplete an aquifer and undermine the sustainability of water resources over the long term. A research study was carried out to elaborate and develop measures for the sustainable preservation of the water resources in a Slovenian karst, in which two approximately 7 km-long tunnels will be driven as part of the construction of the new Divača–Koper railway line. Hydrogeological site investigations were carried out with an aim to evaluate the transmissivity and spatial spreading of the karst aquifer along the route of the tunnels, including the observation of the long-term variation of the groundwater levels and trace experiments. The main findings, which are presented in this paper, were used to develop a methodology for the selection of adequate measures for tunnel construction with an aim of ensuring the sustainability of water resources in karst aquifers. The construction measures comprise limiting the inflows using injection grouting, obscuring the groundwater intake by undrained sections of the tunnel, and constructing bypasses around the tunnel to preserve the current groundwater flow regime. The presented methodology of dynamically accommodating the preventive measures to the actual hydrogeological conditions onsite is generally applicable for common cases in which the state of the karst aquifer could not be pre-determined with a sufficient accuracy of tens of meters to a meter. The spatially and temporally continuous hydrogeological investigations and decision-making charts to reduce the tunnelling’s impact on the karst aquifer are explained in detail in this paper.

scholarly journals Impact of Climate Change on Groundwater Resources

2016 ◽  
pp. 196-221 ◽  
Author(s):  
C. P. Kumar
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
Groundwater Resources ◽  
Climate Variables ◽  
Groundwater Levels ◽  
Impact Of Climate Change ◽  
Surface Water Resources ◽  
The Impact ◽  
The Relationship

Climate change poses uncertainties to the supply and management of water resources. While climate change affects surface water resources directly through changes in the major long-term climate variables such as air temperature, precipitation, and evapotranspiration, the relationship between the changing climate variables and groundwater is more complicated and poorly understood. The greater variability in rainfall could mean more frequent and prolonged periods of high or low groundwater levels, and saline intrusion in coastal aquifers due to sea level rise and resource reduction. This chapter presents the likely impact of climate change on groundwater resources and methodology to assess the impact of climate change on groundwater resources.

Vulnerability assessment of karst aquifers under Mediterranean climates

2020 ◽  
Author(s):  
Philipp Nußbaum ◽  
Márk Somogyvári ◽  
Lysander Bresinsky ◽  
Johannes Löw ◽  
Sarah Schönbrodt-Stitt ◽  
...  
Keyword(s):  
Regional Climate ◽  
Karst Aquifer ◽  
Morphological Characteristics ◽  
Water Volume ◽  
World Population ◽  
Karst Aquifers ◽  
Groundwater Levels ◽  
Carbonate Aquifers ◽  
The World ◽  
Climate Vulnerability

<p>Carbonate aquifers supply freshwater to about one-quarter of the world population. Their particular hydrodynamic behavior is a valuable property for groundwater extraction, on the downside, carbonate aquifers are vulnerable to overexploitation and pollution. Fractures, fissures, and typical karst features, such as  conduits and vertical shafts, create high regional hydraulic conductivities and fast response times to hydrological events, complicating numerical modeling and management of carbonate aquifers in general. Here, we develop a new method to assess the vulnerability of Mediterranean karst aquifers concerning shifts in climate. Particularly, we are interested in 1) which types of karst aquifers are most vulnerable and 2) which factors have the highest impact on their climate vulnerability.</p><p>Our approach is based on a vulnerability index, which is calculated from selected indicators of aquifer behavior that refer to land cover, soil types, wetlands, water demand, current change of groundwater levels, total water volume, run-off, water exploitation index, and freshwater production. First, we calculate vulnerability indices for all karst aquifers – as identified in the World Karst Aquifer Map by the World-wide Hydrogeological Mapping and Assessment Programme (WHYMAP WOKAM v1 database; Chen et al., 2017) – that have at least 90% of their area belonging to Mediterranean climate zones (Csa, Csb, and Csc). Then, we group these aquifers into classes representing different physical behaviors and morphological characteristics (e.g. highly karstified systems in mountainous areas).</p><p>An evident approach to investigate various aquifers in terms of their vulnerability is the development of numerical flow models. The advantage is that the boundary conditions, such as average annual precipitation and temperature, can be modified to consider different climatic scenarios. Thus, the resulting impact on water volumes and the aquifer response can be simulated accordingly. However, this approach requires large amounts of data and high computational costs.</p><p>Our method uses selected sets of karst aquifers representing different variations of Mediterranean climates (i.e. that are similar in terms of temperature and precipitation patterns). These aquifers are compared by analyzing and plotting regional climate variables versus previously calculated vulnerability indices. By identifying and comparing climate-vulnerability relations within aquifer sets, we can mimic changes in climate for individual aquifers in line with the RCP4.5 scenario until 2050. This approach, which relies on present-day observed conditions, allows us to predict the effect of a changing climate on the vulnerability of an aquifer class without the need to develop a complex numerical model.</p><p>The results are visualized in the form of vulnerability maps and used to derive recommendations for the sustainable management of karst aquifers under Mediterranean climates.</p>

scholarly journals Calibration of a lumped karst system model and application to the Qachqouch karst spring (Lebanon) under climate change conditions

2020 ◽  
Vol 24 (9) ◽  
pp. 4275-4290
Author(s):  
Emmanuel Dubois ◽  
Joanna Doummar ◽  
Séverin Pistre ◽  
Marie Larocque
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Karst Aquifer ◽  
Karst Aquifers ◽  
Flow Rates ◽  
Sustainable Water Management ◽  
Lumped Model ◽  
Time Series Analyses ◽  
Spring Flow

Abstract. Flow in complex karst aquifers is challenging to conceptualize and model, especially in poorly investigated areas, in semiarid climates, and under changing climatic conditions; however, it is necessary in order to implement long-term sustainable water management practices. Thus, the objectives of this work were to propose a calibration approach based on time series analyses for a karst aquifer and to assess the impact of climate change on spring discharge. Based on more than 3 years of high-resolution continuous monitoring, a semi-distributed lumped model was calibrated and validated for the Qachqouch karst spring, north of Beirut (Lebanon). Time series analyses and decomposition of spring hydrographs revealed that the system has a high regulatory function, with considerable storage capacity providing stable flow (minimum flow of 0.2 m3 s−1) during the dry season and with flow rates exceeding 10 m3 s−1 during the wet season, which is similar to other karst aquifers in the region. Based on this detailed understanding of the hydrodynamics of the system, the model geometry and parameters were validated. Three linear reservoirs were implemented to reproduce the combined contribution of the different flow components of the system. A satisfactory simulation (Nash–Sutcliffe efficiency coefficient, NSE, of 0.72) of the measured spring flow rates was obtained after calibration. Climate change conditions (+1 to +3 ∘C warming, −10 % to −30 % less precipitation annually, and the intensification of rain events) were added to a baseline climatic year to produce scenarios of expected spring flow responses. Results show that the Qachqouch karst aquifer is sensitive to decreasing rainfall, which is associated with more pronounced recessions, with flow rates decreasing by 34 % and 1-month longer dry periods. Because of the limited influence of snow on the spring flow rate, a warming climate has less impact on spring flow conditions than a reduction in precipitation. Although the model shows that increasing rainfall intensity induces larger floods, recessions, and shorter low-flow periods, the real impact of high-intensity precipitation events remains uncertain, as the model does not account for complex unsaturated and epikarstic processes. This work shows that calibrating a semi-distributed lumped model using time series analyses can be an efficient approach to improve simulations of complex karst aquifers, thereby providing useful models for long-term sustainable water management.

scholarly journals Impact of Climate Change on Groundwater Resources

2017 ◽  
pp. 1094-1120 ◽  
Author(s):  
C. P. Kumar
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
Groundwater Resources ◽  
Climate Variables ◽  
Groundwater Levels ◽  
Impact Of Climate Change ◽  
Surface Water Resources ◽  
The Impact ◽  
The Relationship

Climate change poses uncertainties to the supply and management of water resources. While climate change affects surface water resources directly through changes in the major long-term climate variables such as air temperature, precipitation, and evapotranspiration, the relationship between the changing climate variables and groundwater is more complicated and poorly understood. The greater variability in rainfall could mean more frequent and prolonged periods of high or low groundwater levels, and saline intrusion in coastal aquifers due to sea level rise and resource reduction. This chapter presents the likely impact of climate change on groundwater resources and methodology to assess the impact of climate change on groundwater resources.

Ecological incidents in Northern Adriatic Karst (Croatia)

2000 ◽  
Vol 42 (1-2) ◽  
pp. 281-285
Author(s):  
D. Gereš ◽  
J. Rubinič ◽  
N. Ožanić
Keyword(s):  
Water Resources ◽  
Water Movement ◽  
Groundwater Resources ◽  
Karst Aquifer ◽  
Road Transport ◽  
Karst Area ◽  
Northern Adriatic ◽  
Karst Environment ◽  
Groundwater Aquifers ◽  
Accidental Pollution

In spite of growing efforts to preserve the quality of groundwater resources, accidental pollution is becoming increasingly frequent, resulting in long-lasting impact on the groundwater status. The consequences of ecological accidents are particularly expressed in karst regions, which are caused by the geological properties of the area where the groundwater aquifers are situated, as well as by hydrological circumstances which also influence the dynamic mechanisms of water flow and transportation of pollution in the karst environment. The paper stresses the hydrological component of karst aquifer function and the related role of hydrology in assessment of the hazards caused by accidental pollution and, once the accident has happened, in monitoring the situation and forecasting the possible impact on water resources. The analysis of ecological accidents in the karst has been made, based on the actual examples of accidents involving fuel substances recorded in the Northern Adriatic karst area in Croatia in the period from 1990 to 1998. The basic characteristics of the mechanism of water movement in the karst are presented from the hydrological standpoint, as well as the related risk of rapid transportation of pollutants into the parts of the aquifers used for water supply. The paper also contains proposals for possible approaches to protection of particularly valuable water resources in the karst from accidental pollution occurring in road transport.

scholarly journals Treated Wastewater Irrigation—A Review

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1527
Author(s):  
Mahmoud S. Hashem ◽  
Xue-Bin Qi
Keyword(s):  
Water Resources ◽  
Literature Review ◽  
Wastewater Reuse ◽  
Treated Wastewater ◽  
Negative Effects ◽  
Water Shortages ◽  
Water Resource Utilization ◽  
Extension Program ◽  
Agricultural Demand

As the most important resource for life, water has been a central issue on the international agenda for several decades. Yet, the world’s supply of clean freshwater is steadily decreasing due to extensive agricultural demand for irrigated lands. Therefore, water resources should be used with greater efficiency, and the use of non-traditional water resources, such as Treated Wastewater (TW), should be increased. Reusing TW could be an alternative option to increase water resources. Thus, many countries have decided to turn wastewater into an irrigation resource to help meet urban demand and address water shortages. However, because of the nature of that water, there are potential problems associated with its use in irrigation. Some of the major concerns are health hazards, salinity build-up, and toxicity hazards. The objectives of this comprehensive literature review are to illuminate the importance of using TW in irrigation as an alternative freshwater source and to assess the effects of its use on soil fertility and other soil properties, plants, and public health. The literature review reveals that TW reuse has become part of the extension program for boosting water resource utilization. However, the uncontrolled application of such waters has many unfavorable effects on both soils and plants, especially in the long-term. To reduce these unfavorable effects when using TW in irrigation, proper guidelines for wastewater reuse and management should be followed to limit negative effects significantly.

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