Artesian Water Research Articles

Shallowing of the Svityaz Lake in the context of regional climate change

The paper analyzes the dynamics of the main climatic indicators in order to reveal the role of regional and local factors in the current changes in the water content of the Svitiaz Lake (NW Ukraine). The current state of study of the water balance of the lake and the factors that form it are estimated. The main trends for changes in the levels and regime of surface water, groundwater and artesian water in the territory of the Shatsk National Nature Park are identified. Quantitative data characterizing long-term and modern changes in water levels in the lake are presented. Shallowing of 2019 is characterized (the lowest water level over the last 50 years, reduction of the water mirror area by 8%). Based on statistical mathematical and cartographic analysis of climatic data provided by 17 meteorological stations in the region the dynamics of average annual, monthly and seasonal precipitation, evaporation and their spatial distribution were estimated. A significant increase in evaporation during the warm period of the year over the last decades (2000-2018) has been revealed. Changes in the amount and mode of precipitation over 2 long-term periods are estimated. The peculiarities of the dynamics of the main meteorological indicators in 2019 (average monthly and average annual air temperatures, relative humidity, precipitation amounts) were separately analyzed. Values of humidity coefficients and hydrothermal coefficients were calculated. The parts of the region with the lowest values of these indicators, including the catchment area of Lake Svityaz, are outlined and visualized on the map. The significant role of evaporation growth was confirmed given the consistent increase in air temperatures over the last 20 years. Given the Svityaz station data it is also calculated the correlation coefficients of water levels in the lake with the same indicators for the period since 1970. During the period of 2000-2018, a significant increase in the dependence of water levels on the hydrothermal coefficient of Selyaninov was established, which may indicate a decrease in the ecological stability of the lake and its increasing vulnerability to climate change.

Field investigation on the influence of periglacial processes on pile foundations on the Qinghai–Tibet plateau

AbstractPeriglacial processes can threaten the operation of engineering infrastructure. Based on field observations, the influence of four types of periglacial processes on tower foundations along the Qinghai–Tibet Engineering Corridor were investigated. These periglacial processes change the local thermal and hydraulic processes in soils around the pile foundations, thereby threatening their stability. Frost heaving‐related periglacial phenomena and fast mass wasting are major threats for the operation of pile foundations. The long‐term stability of pile foundations is also threatened by thermokarst‐related periglacial processes and slow mass wasting under the evolving climate change scenario on the Qinghai–Tibet Plateau. Frost weathering has a slight impact on the stability of concrete pile heads, and the long‐term effects of this cannot be ignored. In addition to the impacts of periglacial processes, piles are also affected by engineering problems in areas with shallow artesian ground water, where the use of thermosyphons is associated with frost jacking of the foundations. Further studies are needed on the thermal and hydraulic regimes in soils under the influence of artesian ground water and thermokarst lakes/ponds.

Development of a technology for non-reagent deironing of water for power facilities

As part of the study of the possibility of using hydrodynamic water treatment for preliminary deferrization of artesian water before feeding it to a deep osmotic treatment unit. It was found that in the process of water treatment in a hydrodynamic device with constant air ejection, the complete oxidation of iron (II) compounds occurs. The influence of the volume of consumed air and the number of processing cycles on the efficiency of the deferrization process has been studied. Data were obtained on the distribution (size / ratio) of air bubbles in the fluid flow during its hydrodynamic treatment. Based on the results obtained, it was concluded that when hydrodynamic treatment is combined with ceramic ultra filtration membranes, the iron removal rate is 99%, while hardness salts, hydrogen sulfide and other pollutants are partially removed from the water, and complete disinfection occurs.

Prospective policy safeguards to mitigate hydrogeological risk pathways in advance of shale gas development in the Karoo basin, South Africa

Policies surrounding energy development are frequently implemented in response to known or perceived problems. South Africa is in a unique position to develop prospective policies that build on knowledge gained from elsewhere. This paper provides a prospective analysis of hydrogeological risk pathways and vulnerability attributes in advance of anticipated shale gas operations in the Karoo Basin of South Africa. The ‘hazard-pathways-receptors’ approach is applied to define the hydrogeologic system in the context of potential sources of water resource contamination. This case study focuses on two critical hydrogeological risk pathways: regional groundwater flow and discrete structural features. Depending on the targeted area (hydro-litho-structural domain, depth of target, presence of aquitard, intrusion ratio), the capacity of deep natural pathways to enable hydraulic fracturing fluids, chemicals, or produced water to reach shallow groundwater, will be reduced or difficult. Deep artesian water could however be intercepted at different depths and, based on past groundwater exploration in the Karoo, water could flow into horizontal fractures or openings characterising the shallow aquifers: sills-ring complexes, lithological contacts, and transgressive fractures across dolerite dykes. However, above-ground water and wastewater management safeguards are needed to protect shallow groundwater from potential water quality degradation due to a) flowback or produced water b) stray gas and/or c) spills or illicit discharges that could introduce contaminants into groundwater resources. This paper describes a systematic approach to evaluate hydrogeologic risk pathways and informs adaptive management policies to protect South African groundwater resources.

ASSESSMENT AND FORECASTING OF ARTESIAN WATER QUALITY USING MODERN METHODS OF STATISTICAL DATA PROCESSING

The purpose of this study is to assessment and forecasting of artesian water quality, depending on well depth. This was done by discretization water supply sources by depth, followed by statistical analysis. Samples of groundwater were selected by the project Ukrainian Water Society «WaterNet» «Map of water quality» in the Kiev region for the years 2010-2020.For analysis of the groundwater pollution level were selected following water quality as a total hardness, the salt content, chromaticity, iron, manganese and nitrates. Pollutants such as iron and manganese have been found to occur at virtually any depth in concentrations that exceed the standards for drinking water. However, such quality indicators as nitrates, hardness, color and salt content exceed the norms only in certain ranges of depths. It has also been determined that the concentrations of these pollutants decrease with increasing well depth.So, the most probable contamination of groundwater with exceeding the standards of drinking water nitrates at a depth of 27.5 m and hardness salts at a depth of 45.5 m. Exceeding the standard of water chromaticity is presumably at a depth of 12.5 m. The probability of excessive salinity of groundwater is only at a depth of 27.5 meters.

PURIFICATION OF POLLUTED WATER AT THE MUBAREK GAS PROCESSING PLANT LTD USING BY ION EXCHANGERS

The full chemical composition of the circulating and make-up water of the Mubarek Gas Processing Plant JSC “Uzbekneftigaz” has been investigated. Raw water sources are the Kui-Mazorsk reservoir and groundwater (artesian water).The amount of released impurities after their softening by passing through the layers of the KU-2-8 cation exchanger is determined. This method is simple, effective and energy-saving in water treatment, LLC "Mubarek" GPP.

Preliminary Calculation of the Solar Water-Lifting Installation

Agriculture is one of the most important elements of the economic complex of the Republic of Crimea, which is confirmed by the high development of territories, about 70 percent of the area. To eliminate the acute shortage of water, the article proposes an autonomous system powered by solar energy. This will make it possible to provide water for irrigation on agricultural land. (Research purpose) The research purpose is in searching for and justifying optimal technical solutions for eliminating the problem of water supply to agricultural enterprises of the Republic of Crimea. (Materials and methods) Authors have analyzed the agro-climatic features of the Crimean Peninsula. The article presents the data on the depth of the aquifer on the territory of Crimea, the annual energy potential of solar and wind energy. The article proposes a variant of water supply using artesian water extraction systems powered by solar energy. Authors have calculated the parameters of the solar water supply system. The article presents a diagram of its work. (Results and discussion) The main advantage of a solar installation for water extraction is the ability to use it autonomously in remote areas, without resorting to the construction of expensive engineering structures, which allows us to solve the problem of water supply locally. To ensure the irrigation rate of the apple tree on the territory of one hectare with sufficient solar insolation, a water-based photovoltaic installation is a suitable technical solution. The article presents the total capacity and area of the photovoltaic plant. (Conclusions) The area of the photovoltaic station does not exceed one percent of the total area of the irrigated field. This installation will make it possible to solve the problem of water supply in the region, increase productivity and the overall standard of living of the population. The installation occupies a small area and has a high performance.

Microbial Life in the Deep Subsurface Aquifer Illuminated by Metagenomics.

To get insights into microbial diversity and biogeochemical processes in the terrestrial deep subsurface aquifer, we sequenced the metagenome of artesian water collected at a 2.8 km deep oil exploration borehole 5P in Western Siberia, Russia. We obtained 71 metagenome-assembled genomes (MAGs), altogether comprising 93% of the metagenome. Methanogenic archaea accounted for about 20% of the community and mostly belonged to hydrogenotrophic Methanobacteriaceae; acetoclastic and methylotrophic lineages were less abundant. ANME archaea were not found. The most numerous bacteria were the Firmicutes, Ignavibacteriae, Deltaproteobacteria, Chloroflexi, and Armatimonadetes. Most of the community was composed of anaerobic heterotrophs. Only six MAGs belonged to sulfate reducers. These MAGs accounted for 5% of the metagenome and were assigned to the Firmicutes, Deltaproteobacteria, Candidatus Kapabacteria, and Nitrospirae. Organotrophic bacteria carrying cytochrome c oxidase genes and presumably capable of aerobic respiration mostly belonged to the Chloroflexi, Ignavibacteriae, and Armatimonadetes. They accounted for 13% of the community. The first complete closed genomes were obtained for members of the Ignavibacteriae SJA-28 lineage and the candidate phylum Kapabacteria. Metabolic reconstruction of the SJA-28 bacterium, designated Candidatus Tepidiaquacella proteinivora, predicted that it is an anaerobe growing on proteinaceous substrates by fermentation or anaerobic respiration. The Ca. Kapabacteria genome contained both the sulfate reduction pathway and cytochrome c oxidase. Presumably, the availability of buried organic matter of Mesozoic marine sediments, long-term recharge of the aquifer with meteoric waters and its spatial heterogeneity provided the conditions for the development of microbial communities, taxonomically and functionally more diverse than those found in oligotrophic underground ecosystems.

The use of low-temperature secondary energy resources using heat transformers in non-ferrous metallurgy

The concepts of developing efficient and reliable schemes for the use of waste heat of low-potential energy resources in heat transformers (HT) are considered. Examples of using HT in several non-ferrous metallurgy plants in Russia and Kazakhstan are given: the production of nickel, zinc and ferroalloys. In the case of nickel production, two schemes are proposed for consideration: for summer and winter modes. The main object of study is a nickel production scheme using a lithium bromide absorption chiller (AbCh). Recycled water is the main source of utilized low-grade waste heat for AbCh. The cold obtained in AbCh is necessary for the technological process. The basic parameters were calculated under various extreme conditions, the energy effect of the modernization of the circuit was estimated, and equipment was selected. Studies have shown the feasibility of introducing AbCh into circuits with a large amount of waste heat. Low-grade heat utilization of nickel production using heat pump unit (HPU) in winter allows to obtain heat energy for heating water from the heating network and raw water for feeding the boiler house of a thermal power plant.Another example of HT use is a heat pump unit (HPU) in the production of zinc and ferroalloys. HPU is designed to heat feed water before chemical water purification and at the same time “cool down” the circulating water, which is then used on a series of electrolysis, replacing purchased artesian water. In winter, the heat produced at HPU is used for heating, ventilation and hot water supply, which allows to dispense with the services of a third-party thermal power plant.

Sulfuric acid speleogenesis in the North Caucasus: Sharo-Argun valley Caves (Chechen Republic, Russia)

Geological and hydrogeological conditions in the North Caucasian monocline allow ascending cross-formational flow and discharge of artesian waters from Upper Jurassic and Lower Cretaceous strata, thus enabling hypogene karst. The presence of evaporites (gypsum and anhydrite) in the deep-seated Mesozoic deposits promotes the sulfate-reduction processes, which supply H2S in the waters, thus enabling the sulfuric acid speleogenesis (SAS). Here we report on four hypogene caves of the Sharo-Argun valley. Three caves, Sheki, Magomed, and Kamila are presently active; H2S waters discharge through them. The fourth cave, Said-Emin is in the fossilized state. The active caves are characterized by high H2S contents in the air (up to 60 ppmv), high acidity of condensation solutions (pH 0.5–3.0) and abundant bacterial biofilms and mats dominated by sulfur-oxidizing bacteria. Morphological features of the caves (feeders, condensation-corrosion domes, horizontal water table notches and slots, gypsum replacement pockets, etc.) and mineral deposits (replacement gypsum, native sulfur, minerals of the alunite group) are typical of the cases formed by SAS. Sulfates and native sulfur of the caves have ‘light’ δ34S isotope compositions, consistent with sulfate-reduction in deep seated conditions and subsequent H2S oxidation in the near-surface conditions.

Using Shungite in Water Defluoridation by Galvanocoagulation

Fluorine is a natural component of many sources of drinking water. An excess of fluorine in drinking water leads to metabolic disturbances in bone tissues. In this context, the International Drinking Water Quality Standards recommend adhering to a fluoride content of drinking water of no more than 1.5 mg/dm3. If this value is exceeded, water requires defluoridation. In this work, defluoridation by galvanocoagulation in a drum-type galvanocoagulator was studied. The half-cells of the galvanic couple were aluminum and shungite mined at the Polezhaevskii deposit, Karelia, Russia. The occurring electrochemical processes result in anodic dissolution of aluminum to form the corresponding hydroxides. The fluoride ion forms aluminofluoride complexes with them, which are adsorbed on freshly formed hydroxide flakes. The ratio between the half-cells of the galvanic couple as a significant factor of controlling the process efficiency was studied. It was shown that the fluoride ions were removed most completely at an aluminum : schungite ratio of 1 : 1.5. Experiments on model aqueous solutions of sodium fluoride detected a significant dependence of the process on the initial pH value. The experimental results enabled one to choose a mode of defluoridation of water with various fluoride contents. By the example of treatment of artesian water with a fluoride content of 9.1 mg/dm3 from Mashevka, Poltava oblast, Ukraine, a high efficiency of the studied process was demonstrated: the fluoride ion content of the water treated for 5 min decreased to 0.9 mg/dm3. In addition, when using shungite as a half-cell of the galvanic couple, its disinfecting effect was observed: whereas the initial content of coliform bacteria was 700 in 100 cm3, they were absent in the treated water. The redox potential was also reduced from 340 to 255 mV, which is noteworthy because this parameter has recently received considerable attention as being one of the most important parameters of water in its interaction with the human body.

Potentialities of Membrane Water Treatment for Removing Organic Pollutants from Natural Water

The potentialities of using ultrafiltration, nanofiltration, and reverse-osmosis membranes for removing organic compounds from water are considered. Experimental results obtained by the authors and the information taken from the literature characterizing the interaction between membranes and organic compounds contained in natural water are presented. Data are obtained concerning the efficiency of different membrane technologies in the removal of organic compounds from natural water. The growth rate of the deposits of organic substances having different molecular weight has been studied. The effect of the membrane’s material and the hydrodynamic mode of the membrane’s operation on the formation rate of organic deposits has been demonstrated. The influence of these substances’ nature, their concentration in natural water, and the molecular weight thereof on the deposition rate on membranes have been revealed. In the experiments, tap water taken from the Moscow water supply and river water were used. The results of the authors’ experiments and the results obtained by other Russian and foreign researchers presented in the paper make it possible to consider ultrafiltration as a reliable way to retain organic macromolecules as well as finely dispersed and colloidal impurities. With retaining low-molecular organic compounds that determine the color of water, ultrafiltration is restricted. In the synthesis of nanofiltration membranes, films with different pore size and charge are used. Therefore, for a specific water source and water consumer, an individual choice of nanofiltration membranes is required, a wide range of which is available in the market. Nanofiltration membranes of the NE-90 and NE-70 types for surface waters having a color of 20–100 degrees provide a 85 and 75% decrease in the oxidability level, respectively. According to the results of studies concerning the efficiency of artesian water purification, domestic OPMN-K nanofiltration membranes can also profoundly purify water from natural organic compounds. Among all the membranes used in the water treatment technology, reverse-osmosis membranes have the smallest pore size; their use provides retaining organic compounds with a molecular weight lower than 100 Da. The studies have shown that reverse-osmosis membranes exhibit a 99.5% retention level for the compounds with a molecular weight of 150 Da and a 99.9% retention level for the compounds with a molecular weight higher than 1000 Da. To reveal the nature and concentration of organic compounds deposited on the membranes, water spectrograms have been used.

ВОЛЬТАМПЕРОМЕТРИЧЕСКОЕ ОПРЕДЕЛЕНИЕ ПЕРОКСИДА ВОДОРОДА C ПОМОЩЬЮ СЕНСОРОВ НА ОСНОВЕ НАНОЧАСТИЦ СЕРЕБРА В ОБЪЕКТАХ ТЕХНОГЕННОГО И ГЕОЛОГИЧЕСКОГО ПРОИСХОЖДЕНИЯ

Актуальность работы связана с необходимостью определения низких содержаний пероксида водорода в объектах техногенного и геологического происхождения. Цель: разработать сенсор с повышенной чувствительностью на основе наночастиц серебра для контроля окружающей среды и определить концентрацию пероксида водорода в водных объектах. Объекты: артезианская и дождевая вода, собранная в черте города и пригорода. Методы: просвечивающая электронная микроскопия, вольтамперометрия. Результаты. Форма и размер наночастиц серебра зависят от природы восстановителя. При использовании двух восстановителей боргидрида и цитрата натрия получают частицы сферической формы наименьшего размера – от 0,5 до 17,5 нм. При использовании цитрата натрия получают наночастицы серебра большего диаметра – от 10 до 55 нм, различной формы: сферические, призматические и треугольные. Наночастицы серебра, полученные с использованием боргидрида натрия, агломерированы в цепочки размером до 65 нм. Особенностью электровосстановления нанофаз серебра, полученных в присутствии цитрата натрия, на поверхности графитового электрода в 0,1 М NaOH является восстановление ионов серебра из комплексных соединений [Ag(OH)2]–. Предложен механизм электрохимических процессов перехода нанофаз серебра, полученных с использованием различных восстановителей. Этот механизм не зависит от природы восстановителя. Установлено, что катодный максимум при Ек=0,08 В соответствует процессу восстановления пероксида водорода. Зависимость катодного максимума от концентрации пероксида водорода, полученного с использованием сенсора на основе наночастиц серебра в присутствии цитрата натрия, была линейной в диапазоне от 0,1 до 1 нМ, предел обнаружения составил 0,087 нМ. Определена концентрация пероксида водорода в дождевой и артезианской воде. Предложен простой чувствительный сенсор на основе наночастиц серебра, полученный с использованием восстановителя цитрата натрия. Этот сенсор имеет широкий диапазон концентраций для определения пероксида водорода.

Mechanism of valley narrowing deformation during reservoir filling of a high arch dam

During the reservoir filling of many high arch dams, it was observed that the valley slopes on both sides deformed towards the river. The measured value of valley narrowing lateral deformation (VNLD) reached 89.54 mm by October 2018. This rare phenomenon contradicts the traditional experience of dam engineering and lacks a convincing explanation. An arch dam project in China is selected as a case study to analyze the mechanism of the VNLD. Based on a comprehensive analysis of the geological background and the VNLD measurements, a numerical study is performed to identify the main factors that may contribute to the VNLD phenomenon. It is concluded that the time-dependent valley deformation is due to the rheological behaviour of rock mass with the change of hydrogeological conditions. The artesian water head in the deep-confined aquifer is increased and the mechanical parameters in fault and shear zones are weakened after reservoir filling, which is associated with the specific hydrogeological structures. The rise of artesian water head is the main induced factor that contributes to the uplift deformation, which is observed at the dam site, and can cause the VNLD in the horizontal direction. The simulated results considering these factors agreed well with the observed data.

The annual total artesian water diversion plan of 300billion Square meters in the arid desert area of northwest China

The water shortage in the arid desert area of northwest China has seriously restricted the healthy, balanced and sustainable development of the national economy. In the arid desert area of northwest China, the total budget of the full artesian water diversion project of 300billion square meters per year is less than 3trillion yuan, and the construction period is less than 10years. Hope the central government, Ministry of Water Resources, ministry of agriculture, ministry of water and power. And other major national economy and people's livelihood related departments and many experts and scholars, people with lofty ideals to pay high attention in a timely manner.

Novel Approach to Automated Flow Titration for the Determination of Fe(III).

A novel approach to automated flow titration with spectrophotometric detection for the determination of Fe(III) is presented. The approach is based on the possibility of strict and simultaneous control of the flow rates of sample and titrant streams over time. It consists of creating different but precisely defined concentration gradients of titrant and analyte in each successively formed monosegments, and is based on using the calculated titrant dilution factor. The procedure was verified by complexometric titration of Fe(III) in the form of a complex with sulfosalicylic acid, using EDTA as a titrant. Fe(III) and Fe(II) (after oxidation to Fe(III) with the use of H2O2) were determined with good precision (CV lower than 1.7%, n = 6) and accuracy ( lower than 3.3%). The approach was applied to determine Fe(III) and Fe(II) in artesian water samples. Results of determinations were consistent with values obtained using the ICP–OES reference method. Using the procedure, it was possible to perform titration in 6 min for a wide range of analyte concentrations, using 2.4 mL of both sample and titrant.

About Total Alpha Activity of Underground Water Sources

Artesian wells remain strategically important sources of drinking water for the Kyiv megacity, especially in the vicinity of radioactively contaminated areas of the Chornobyl exclusion zone. The contribution of groundwater to the total volume of drinking water was indicated. The water from 144 artesian wells was investigated in terms of total alpha activity: 67 of them were drilled up to the Cenomanian aquifer of the Upper Cretaceous, 77 - up to the Bajocian aquifer of the Middle Jurassic.
 Studies have found that the total alpha activity in 39 wells exceeds the regulatory limit, with 37 of the 39 wells supplying water from the Bajocian aquifer. The average total alpha activity of the Cenomanian water is 0.033 ± 0.003 Bq/dm3, the most active water of this aquifer is produced in the Obolon area where the average value equals 0.045 ± 0.004 Bq/dm3. The average total alpha activity of the Bajocian water is 0.115 ± 0.012 Bq/dm3, the most active water of this aquifer is produced in the Obolon and Troyeshchyna areas where the average values equal 0.097 ± 0.010 Bq/dm3 and 0.188 ± 0.018 Bq/dm3, respectively. Therefore, in average, the Bajoian water is 3.5 times more active than the Cenomanian one: the average activity reaches 0.115 ± 0.012 Bq/dm3 against 0.033 ± 0.003 Bq/dm3.
 GIS mapping of the total content of α-emitters in the groundwater of both aquifers was created. The dynamics of the gross alpha activity of artesian water from both aquifers was monitored for the Obolon area. It was determined that when consuming the Bajocian water, two times more alpha-emitters enter the human body than from the Cenomanian water.
 The processing of the results through the spline interpolation with the Spatial Analyst Tools module ArcGIS 10.1 made it possible to analyze this trend for the megacity area: geological and tectonic factors such as block movement of the foundation, unequal incision of ancient watercourses into the pre-Bajocian surface and the erosion of sediments had always had the greatest influence on the enhanced alpha activity of the Bajocian water.

An integrated remote-sensing mapping method for groundwater dependent ecosystems associated with diffuse discharge in the Great Artesian Basin, Australia

Vertical leakage (discharge to upper aquifers) is an important but poorly constrained component of water balance in the Great Artesian Basin (GAB), Australia. It ranges from negligible discharge where the GAB is overlain by aquitards, to high discharge where artesian water feeds the shallow unconfined aquifer (thereby raising the water table) causing elevated surface soil moisture and extensive surface salinisation. Adequately representing the temporal and spatial variability of vertical leakage is difficult due to the large scale over which the discharge occurs. An innovative method is presented that integrates a supervised classification of high-discharge zones using time-series Landsat data with landform mapping information to improve classification results. ‘Wetness persistence’ and ‘salt persistence’ classes, determined from the time series data, are related to groundwater discharge processes through a discharge framework that allows scaling up of field-based discharge estimates. The results show that using multi-image classification integrated with landform data will significantly reduce uncertainty by reducing false positives. No significant temporal trends were found in a time series assessment, with results featuring high variability, most likely due to image normalisation issues. The lack of a clear temporal signal suggests that an assumption of steady-state discharge is valid for estimating annual fluxes of vertical leakage. Supervised classification and landform outputs provide updated knowledge on GAB vertical leakage rates by providing useful lower and upper bounds of discharge rates respectively. Additionally, groundwater-dependent ecosystem classification, covering the full extent of the basin margins, is a new source of information resulting from the work.

Holocene large lake development and desiccation: Changing habitats in the Kharga Basin of the Egyptian Sahara

AbstractThe Sahara Desert, known today as one of the world's great wildernesses, was periodically dotted with large lakes that formed during the Holocene pluvial periods. As the lakes dried, the fertile and flat‐lying damp muds formed a rich habitat that was occupied by human settlers before being abandoned, as the area dried out completely. In Kharga, our work shows that a combination of pluvial periods with short term storage in the Upper Nubian aquifer, access to artesian water in the Lower Nubian Aquifer and over‐flow water from the Nile via the Wadi Toshka created a biodiverse environment which, although drier today, sustained refugia of plants and animals throughout the Holocene.

INCREASING WATER AVAILABILITY IN THE NORTH-EASTERN CRIMEA

The formation of water-deficit conditions in most of the territory of the Crimean Peninsula causes the redistribution of surface and underground runoff between regions. Available volumes of water resources in various regions of the Crimea are distributed unevenly, which requires the construction of long water supply routes. To improve water supply, a water supply System has been developed for the Eastern Crimea with artesian water from wells in the South-Eastern part of the Crimean Peninsula.