Karst aquifers are one of the main potable water sources worldwide. Although the exact global karst water utilisation figures cannot be provided, this study represents an attempt to make an upgraded ...assessment of earlier and often circulated data. The main objective of the undertaken analysis is not only to provide an assessment of the utilisation of current karst aquifers, but also to estimate possible trends under various impact factors such as population growth or climate changes. In > 140 countries, different types of karstified rocks crop out over some 19.3 × 10
6
km
2
, covering > 14% of ice-free land. The main ‘karst countries’, those with > 1 × 10
6
km
2
of karst surface are Russia, USA, China and Canada, while among those with > 80% of the territories covered by karst are Jamaica, Cuba, Montenegro and several others. In contrast, in a quarter of the total number of countries, karstic rocks are either totally absent or have a minor extension, meaning that no karst water sources can be developed. Although the precise number of total karst water consumers cannot be defined, it was assessed in 2016 at approximately 678 million or 9.2% of the world’s population, which is twice less than what was previously estimated in some of the reports. With a total estimated withdrawal of 127 km
3
/year, karst aquifers are contributing to the total global groundwater withdrawal by about 13%. However, only around 4% of the estimated average global annually renewable karstic groundwater is currently utilised, of which < 1% is for drinking purposes. Although often problematic because of unstable discharge regimes and high vulnerability to pollution, karst groundwater represents the main source of potable water supply in many countries and regions. Nevertheless, engineering solutions are often required to ensure a sustainable water supply and prevent negative consequences of groundwater over-extraction.
Edited by two world-renowned hydrologists, this book will provide civil and environmental engineers with a comprehensive reference for managing and sustaining the water quality of springs. With ...contributions from experts from around the world, this text covers many of the world's largest springs, providing a unique global perspective on how engineers around the world are utilizing engineering principles for coping with problems such as: Mismanagement, overexploitation and their impacts on both water quantity and quality. The book is divided into two parts: Part One will explain the theory and principles of hydrology as they apply to springs while, Part Two will provide a rare look into the engineering practices used to manage some of the most important springs from around the world.
Subsurface dams could be an optimal solution for storing floods or waters of temporary streams in countries with arid and semi-arid climatic conditions. Many such structures are already completed in ...the northern and eastern African countries and Middle East, but many other prosperous locations require feasibility assessment and construction if found appropriate. Two types of dams are common: one built in the karst (for direct recharge), and the other into the karst connected alluvial aquifer (for indirect recharge). The former is very rare due to its complicated construction and threat of water leakage. The latter has more often, but not always been applied with the aim to improve storage in karst, but as an indirect effect of damming of the flow in adjacent alluviums. This article discusses some positive experiences with dams built in northern Iraq, Algeria, Ethiopia and Somalia and advantages of the application of such subsurface structures in several potential locations in countries with a prevailing arid and semi-arid climate, but it also explores uncertainties which end-users may face if the engineering design is not prepared based on results of a proper research programme.
South-eastern Dinarides comprise territories of four countries of SE Europe—Croatia, Bosnia and Herzegovina, Montenegro and Albania and their parts belonging to the Adriatic basin. The region ...consists mainly of highly karstified carbonate rocks and is characterised by a high precipitation rate. As a result, karst aquifers can accumulate large amounts of groundwater issuing at numerous karst springs, some being the world’s largest in terms of maximal flow. Locally, the annual total rainfall rate sometimes reaches 5000 mm or even more, while an average specific groundwater yield of examined karst aquifers ranges from 40 to 50 l/s/km
2
. However, as discussed in this paper, the region also has many contrasts: abundant water reserves yet water shortage in certain parts, natural phenomena and wonders yet limited sources of life, good natural water quality marred by its vulnerability to pollution, feasible engineering solutions accompanied by their partly negative impact on environment, and water management at the national level contrasting with the transboundary character of most large aquifers. Doubts whether waters from this “treasury” are utilised in the best way and what the prospects are for their sustainable use and protection in the future are also analysed in the text.
The lakes Ohrid and Prespa are located on the Balkan Peninsula, at the border between Albania, North Macedonia and Greece. They are separated by the high mountain chain of the Mali Thate-Galičica, ...which consist of highly karstified rocks, through which water from Lake Prespa drains into Lake Ohrid. This area has been a UNESCO world heritage site since 1979. A very rapid decrease of the level of the big Prespa Lake was observed during the period 1963–2020. There are different explanations and hypotheses in an attempt to explain the decrease of lake levels. These are: (a) an increase of transmissibility of the karst aquifer separating these lakes, caused by geologic–tectonic reasons and resulting in intensification of drainage; (b) the increased use of lake water by the local population for agricultural, industrial and other purposes, and (c) the effects of recent climate changes. The paper presents information about the hydrogeology of the region for the purpose of better understanding the formation of the karst water resources and the characteristics of their circulation. Analysing a large number of investigations which unevenly covering the investigated area, the authors concluded that the current catastrophic decrease of the level of Lake Prespa is largely the result of climate changes that have occurred in the last 60 years, as well as the non-effective management of the water resources. The severity of the problem, reflected directly in the well-being of the local population, requires cooperation of the scientists of the three countries in question with respect to the realisation of the goal of the investigation and the protection of water resources of Lake Prespa.
Karst environments are characterized by distinctive landforms and a peculiar hydrologic behavior dominated by subsurface drainage. Karst systems can be extremely complex, heterogeneous, and ...unpredictable due to the wide range of geological and hydrological controlling factors. The great variability results in serious problems for engineers, and in difficulties to characterize the karstified rock masses, and in designing the engineering works to be performed. The design and development of engineering projects in karst environments require specific approaches aimed at minimizing the detrimental effects of hazardous processes and environmental problems. Further, karst aquifers (that provide approximately 20–25 % of the world’s drinking water) are extremely vulnerable to pollution, due to the direct connection between the surface and the subsurface drainage, the rapidity of the water flow in conduit networks, and the very low depuration capability. Sinkholes are the main source of engineering problems in karst environments, and may cause severe damage in any human structure. The strategies and solutions that may be applied to mitigate sinkhole problems are highly variable and largely depend on the kind of engineering structure, the karst setting, and the typology and size of the sinkholes. A sound geological model, properly considering the peculiarities of karst and its interactions with the human environment, is essential for the design of cost-effective and successful risk reduction programs. Due to the unique direct interaction between surface and subsurface environments, and the frequent ground instability problems related to underground karstification, management of karst environments is a very delicate matter. Disregarding such circumstances in land-use planning and development inevitably results in severe problems with high economic impacts. Karst environments require specific investigation methods in order to properly manage and safeguard the sensitive geo-ecosystems and natural resources associated with them.
The Commission on Karst Hydrogeology, also known as the Karst Commission (KC), was founded in 1970 in Neuchâtel, Switzerland, and it is an important part of the International Association of ...Hydrogeologists (IAH). The general idea was to organise a group of hydrogeologists from different countries, with relevant experience in karst hydrogeology, to promote cooperation among scientists interested in karst topics, exchange experiences and, particularly, create an optimal strategy for groundwater resources development. From foundation until today, more than 40 formal meetings and many informal KC gatherings (including field trips) have been convened in different karst regions, and a number of papers and books have been published by KC members. The first publication in the IAH book series
International Contributions to Hydrogeology
(the “blue books”) was on the subject of karst, presenting the experiences gleaned from a number of development projects from various karst regions, as well as bibliographic data on karst research of the time. Today, the KC is one of the most active IAH groups, with 70 permanent members from 6 continents and many young researchers, whose work is supported by funding and regular awards. The KC members have led or have been involved in many projects run with international cooperation. The two largest, completed in the course of the past decade, are the World Karst Aquifer Map (WOKAM) and the Dinaric Karst Transboundary Aquifer System (DIKTAS) projects. This paper summarizes the history of the KC to date.
The new GIS-based CC-PESTO method is shown to successfully assess and map the vulnerability/resilience of karst aquifers to effects of climate change. Karst aquifers were chosen due to their ...importance at the global level and widespread utilisation in potable water supply and irrigation, but also because of their hydrogeological complexity. The method was developed to assess the intrinsic vulnerability of aquifers, without considering the direct impact of variable climate factors, but considering the adaptive capacity of aquifers in response to expected climate extremes (floods and prolonged droughts). The procedure includes a subdivision of aquifer systems and an assessment of four main attributes: permeability, storativity, the discharge regime and the slope of each of the subdivided segments. CC-PESTO was tested in three study areas located in the highly developed karst of Montenegro and Serbia. In Mt. Durmitor (Montenegro), four out of 21 subunits were found to belong to the category of ‘low vulnerability’ and to have a good prospect for further development. Two subunits in the Babine and Bogovina study areas (Serbia) were defined as less vulnerable than others. The results obtained should help water managers and spatial planners to safeguard and reserve these areas as alternative or supplementary water sources that might be able to reduce the shock on groundwater-dependent ecosystems caused by expected extended droughts. The CC-PESTO method is flexible, and its application is possible in other karstic terrains such as platform or tropical karst. Indexation of the main attributes and their subcomponents could be adapted to local circumstances.
•A new flotation tailings treatment process was developed for efficient Cu recovery.•An efficient Cu dissolution was achieved in an H2O media in presence of pyrite.•The dissolution mechanism of ...CuFeS2 has been confirmed to be a multistage reaction.•Fe was always co-dissolved with Cu following a linear relation of CFe = 38.393 × CCu.•Over 91% Cu was extracted from pregnant leach solutions by LIX-84I in Kerosene.
Sulfide copper mineral, typically Chalcopyrite (CuFeS2), is one of the most common minerals for producing metallic copper via the pyrometallurgical process. Generally, flotation tailings are produced as a byproduct of flotation and still consist of un‒recovered copper. In addition, it is expected that more tailings will be produced in the coming years due to the increased exploration of low‒grade copper ores. Therefore, this research aims to develop a copper recovery process from flotation tailings using high‒pressure leaching (HPL) followed by solvent extraction. Over 94.4% copper was dissolved from the sample (CuFeS2 as main copper mineral) by HPL in a H2O media in the presence of pyrite, whereas the iron was co‒dissolved with copper according to an equation given as CCu = 38.40 × CFe. To avoid co‒dissolved iron giving a negative effect on the subsequent process of electrowinning, solvent extraction was conducted on the pregnant leach solution for improving copper concentration. The result showed that 91.3% copper was recovered in a stripped solution and 98.6% iron was removed under the optimal extraction conditions. As a result, 86.2% of copper was recovered from the concentrate of flotation tailings by a proposed HPL‒solvent extraction process.
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