Groundwater Reservoir Research Articles

Косейсмическая химическая гидрогеодинамика Култукского резервуара подземных вод: индикаторные роли Na/Li, 234U/238U и 234U

Within the framework of the complete seismogeodynamic cycle of the central part of the Baikal Rift System, in the series of hydrogeochemical data obtained in 2012–2022 at stations of the Kultuk polygon, variations of the thermophilic elements Na and Li and Na/Li ratios are traced in connection with changes in the 234U/238U activity ratios and 234U activity, reflecting the opening and closing of microcracks for circulating groundwaters. Coseismic chemical hydrogeodynamics of the Kultuk groundwater reservoir is considered in terms of temperature and extension–compression of the crust.

Recharging the Freshwater Coastal Aquifer of Sidi Kirayr Area Using Sustainable Infiltration Trenches

Egypt is considered an arid country and depends mainly on the Nile River and groundwater reservoirs to supply water for drinking and various uses. The northwestern coastal zone is one of the regions that rely heavily on groundwater and rainwater for drinking and irrigation. As a result of changes in climate and the rise in sea level, the increase in seawater intrusion is growing. Furthermore, groundwater exploitation and increased pumping of some wells installed in this area have a negative impact on the amount of water in the region’s subterranean reservoirs. One of the approaches suggested for managing freshwater lenses floating on top of seawater from saltwater intrusion in this region is to recharge the aquifer lenses with fresh water. This can be done either by injection wells or by use of groundwater mounds, i.e., infiltration trenches. Due to the expected higher cost operation of injection wells, it is interesting to study the recharge of freshwater lenses through the use of groundwater mounds. Studies have been carried out in the past on the Sidi Kirayr area in terms of recording the water table levels and the amount of rainfall before and after the rainy season. However, we propose using an environmentally sustainable economic solution to recharge the underground reservoirs through the use of rainwater instead of letting it run off into the sea. In this respect, an infiltration trench is designed to recharge the aquifer in the Sidi Kirayr area. Two design types for the trench are proposed, with the geometrical calculations of the appropriate dimensions. The trenches are suggested north and south of the asphalt road in the area of Sidi Kirayr, providing that the trenches can be recharged by rainfall or surplus water when being available from other sources.

Горячинская активизация Ямбуйской зоны транстенсии в 2013–2015 гг.: Косейсмическая химическая гидрогеодинамика подземных вод на ЮВ побережье Среднего Байкала

Variations of Si, Na, Li, 234U activity, and 234U/238U activity ratio in thermal and cold groundwaters, as well as cooled hydrotherms from active faults in the SE coastal area of Middle Baikal are considered. For the Maksimikha area, hydrogeochemical monitoring data of 2013–2015 with interpretation in terms of chemical hydrogeodynamics: temperature, depth of water reservoir and opening–closing of microcracks for circulating water. When comparing series of hydrogeochemical monitoring with a series of earthquakes K = 10.5–12.7 of the Goryachinsk seismic reactivation in Middle Baikal, an increased sensitivity of responses to earthquakes at the station of cooled hydrotherms from the transition zone of the lower hydrogeodynamic floor is revealed in comparison with the responses of fracture-derived cold water from the upper floor. The Maksimikha groundwater reservoir is considered as a representative reservoir located along the in the Yambuy transtension zone that is lateral structure of the South Baikal basin. Coseismic hydrogeodynamics of the Maksimikha reservoir in 2013–2015 is referred to the time interval preceding the landmark Goloustnoye earthquake on September 05, 2015, which corresponded to the conditions of maximum compression of the crust of the Kultuk reservoir, localized at the main structural line of the Baikal Rift System, in the 2008–2020 seismogeodynamic cycle.

Химическая гидрогеодинамика в Улан-Баторском резервуаре подземных вод в 2012–2023 годах: сопоставление с химической гидрогеодинамикой резервуаров побережья Байкала

Comparative hydrogeochemical studies of groundwater in the Ulaanbaatar reservoir and those in the coast of Lake Baikal show significant difference between hydrogeodynamic processes of these areas, the earlier generation of U-isotopic and Si–Na–Li-temperature anomalies in the Ulaanbaatar groundwater reservoir and the later in those of the Baikal coast.

Valuation and Pricing of Surface Water Supplies in Pakistan

Pakistan has the largest contiguous, well-articulated, and comprehensive irrigation system in the world, with 3 storage reservoirs, 68 small dams, 19 diversion barrages, and 45 canal commands with 12 Link Canals for inter-basin transfer of water. About 0.1 million outlets supply water to the farmers to irrigate land besides more than 600,000 tubewells. The whole irrigation network commands an area of 45 million acres (18.22 Mha) out of which 79 percent is irrigated by canals or tubewells/wells. More than half of the canal irrigated areas (58 percent) is irrigated perennially and 42 percent nonperennially [NWSR (2002)]. The average annual flow of Indus River System is approximately 151.58 million acre feet (MAF) of which presently 103.81 MAF (128.1 BCM) is being diverted to irrigate farm lands [NWSR (2002)]. The present live storage capacity of the reservoirs is about 12.5 MAF (13 percent of river flows) compared with the original capacity of 15.7 MAF. The hydropower generation is constrained by seasonal inflows to reservoirs and irrigation requirements by Indus River System Authority. The generation dictated by irrigation requirements is the highest in the months of July to October. Little more than half of the diverted flows (55 percent) become available at farm gate, 42 percent infiltrate to groundwater reservoir and balance 3 percent is lost as evaporation. Of the total water that seeps down to the groundwater reservoir, including some 27 percent of farm gate supply through field seepage, nearly 85 percent is being extracted. Groundwater owing its existence to operational canal system, supplies over 40 percent of crop water requirements of the country

Deciphering natural and anthropogenic effects on the groundwater chemistry of Nago City, Okinawa Island, Japan

A qualitative assessment of groundwater resources is significant in islands that largely depend on individual aquifers. In Okinawa Island, Japan, limestone aquifers are valuable groundwater reservoirs. However, these aquifers are sensitive to contamination due to high permeability in the conduit network. Although human activity has increased in recent decades, there remains insufficient hydrological information to assess the impact of anthropogenic loading on groundwater quality in Okinawa Island. To address this, we analyzed 4 seepage, 16 river, and 14 shallow (<10 m in depth) groundwater samples to obtain baseline chemistry and anthropogenic impact information on groundwater resources in central Nago City, northern Okinawa Island. We divided the region into three landscape units: lowland (<30 m asl), eastern, and western areas. Except for a limited number of water samples collected in the eastern mountain and coastal section of the lowland, the hydrochemistry was characterized by Ca–HCO3 type, indicating carbonate weathering within limestone-bearing lithology and Quaternary deposits. Divergent water 87Sr/86Sr values (0.707723–0.712102) with lower Sr concentrations (0.1–1.6 μmol/L) in the mountains and convergent values (0.708859–0.709184) with higher Sr concentrations (0.3–17.6 μmol/L) in the lowland suggest that the water–rock interactions in the lowland aquifer composed of Quaternary deposits are mostly responsible for the hydrochemistry of groundwater resources. The local meteoric water line (δD = 6.38 δ18O + 3.36) indicated that the water originates from precipitation, the altitude effect, and evaporation. The δ15N and δ18O in NO3− indicated the addition of manure and septic waste in the lowland aquifer. The results imply that detecting source areas of anthropogenic NO3− prior to serious groundwater pollution is important (regardless of the NO3− concentration), and isotope analyses would aid in developing appropriate action plans to mitigate or prevent future water pollution by NO3− in island regions.

Astronomically forced changes in groundwater reservoirs and sea level during the greenhouse world

<p indent="0mm">Sea level rise caused by global warming is one of the biggest challenges facing humankind. Deepening the understanding of the mechanism of global sea level change during the greenhouse period is the key to meeting this challenge. Large-scale, rapid sea-level changes frequently occurred during the greenhouse period lacking ice sheets. However, conventional sea level change models cannot explain this phenomenon, exposing their shortcomings. Estimation of global pore space in sediments and big data studies have indicated that global sea level changes may also be related to climate-related continental groundwater volume changes. We review the mechanism of sea level change caused by astronomically driven continental groundwater activities and propose a new Sponge Continent hypothesis: astronomical forcing drives climate change, causing filling and discharge of continental aquifers (by analogy, a sponge), which may in turn impact large-scale changes in global sea levels and inland lake level during the greenhouse period. We summarize recent technological breakthroughs related to the reconstruction of deep time sea- and lake-level changes. First, lake level change has been proposed as an indicator for the fluctuation of continental groundwater volume. Second, the sedimentary noise model and SediRate-Fischer method were proposed for the reconstruction of sea- and lake-level changes from sedimentary successions. Among these, the sedimentary noise model is developed based on the principle of the Milankovitch theory of climate change and time series analysis techniques. The noise model contains two complementary methods: dynamic noise after orbital tuning (DYNOT) and lag-1 autocorrelation coefficient (<italic>ρ</italic>₁). The DYNOT method measures the noise intensity in paleoclimate time series, i.e., the ratio of non-Milankovitch variation to total variation. By calculating the lag-1 autocorrelation coefficient of the target paleoclimate time series, the <italic>ρ</italic>₁ model can independently test the noise changes related to sea level variations. The <italic>ρ</italic>₁ value decreases with the increase of noise intensity, and vice versa. The relative intensity of the sedimentary noise is anti-phased with the sea level change. When the sea level increases, the sedimentary noise decreases, and vice versa. This model can also be applied to the studies of lake level changes. Third, cyclo-magnetostratigraphy can provide a global synchronous stratigraphic correlation framework, which is vital for the evaluation of the aquifer eustasy and Sponge Continent hypothesis. The hypothesis of aquifer eustasy and Sponge Continent can be supported by geological evidence from the greenhouse period. This paper reviews recent progress related to astronomically forced sea level changes and/or lake level changes in chronological order. Some of them support the predicted antiphase relationship between the sea level curve and the contemptuous lake level curve as predicted by the Sponge Continent hypothesis. However, many unsolved issues about the nature and mechanisms of sea level change are to be explored. First, estimates of groundwater volume remain in dispute. Second, there is a lack of quantitative indicators for deep time groundwater variations. Third, the timing and mechanism of groundwater changes in continental aquifers are still unconstrained. Potential research directions are also discussed, including groundwater storage estimate, research methods, storage-drainage mechanism of groundwater reservoirs, etc.

Spatial variability of surface water runoff and sedimentary output of the Sartka Valley Basin using the KINEROS simulation model

Abstract: The amount of water seeping into ground is varied across the study area، so the central region have a rich groundwater reservoirs due to higher water seeping ratio into the ground. - Runoff is concentrated in the most northeastern parts of the basin، and this runoff is useful in the application of water harvesting methods of various types. It is useful in the design of small dams and ponds، then constructing a dam with medium capacity at the estuary of the basin in order to collect excess water of the study area. The study recommended establishment of weather station and hydrological cross sections to measure discharge of the catchment، it also recommend using the flood water to feed and recharge the underground stock and rising groundwater table. Forecasting the water yield and the sedimentary output that results from a rainstorm on the river basins has not taken a large place in the hydrological studies yet، so one of the unmeasured catchment of temporary flow (Sartaka basin) was chosen for this study، it locates the extreme southwest of Shaqlawa district. The basin originates from the southern slopes of Safin mountain، which is a tributary of the Gomaspan basin. Earlier but especially in the recent years the geography has witnessed using the application of modern methods، including quantitative programs and techniques، to reach more accurate results far from description and generalization. Therefore، the study seeks to find solutions for water harvesting and reducing the manifestations of water scarcity in the study area، by modeling and simulating the relationship between climatic variables on the one hand، and surface water runoff and sedimentary product on the other hand، through experimental and programmatic methods using the (KINEROS) tool. The importance of the study is solving the water scarcity in the region and reshaping and organizing the environment of the area for the sake of developing social life in general. This study has come to end with some conclusions as stated below: - The feeding source of the basin is rainwater، which falls and takes place in the valleys during the rainy season.

The Impact of Urban Livestock Waste on the Environment in Potiskum Town Yobe State, Nigeria

Livestock provide essential commodities and services to the majority of the world's population. With an increasing number of people, livestock are increasingly held responsible for many adverse effects on human health. The aim of the study is to examine the management strategies applied by urban and pre-urban livestock producers and their resultant consequences on the land, water, and health of the general public, emanating basically from small land holdings in Potiskum. The objectives of the study are to identify the locations of major dumpsites close to water points and to assess pollution incidence as it relates to public health. Ten-five water samples and/or soil samples were tested in an analytical chemistry laboratory. To assess the level of toxicity, a microbial test was also conducted in Biological laboratory. In addition to this approach, a 200-meter buffer radius was created around each water point, and 6 livestock keepers (household heads) within it were randomly selected for interview using a questionnaire survey. Descriptive statistics were used with SPSS/PASW version 18.0, and the results were presented using statistical tools such as percentage computation, frequency distribution table, line, and bar graph, respectively. Findings revealed heavy metals were found above the recommended water drinking level of WHO and Nigeria's standards. These include Magnesium (0.98), Iron (4.900), Chromium (3.30), Copper (1.520), Cadmium (0.84), Sulphate (15.30), Nitrite (2.25), Lead (2.20) as opposed to the acceptable levels of 0.1, 0.1, 0.05, 0.2, 0.003, 100, 0.2 and 0.01. More than 60% of the respondent's views revealed that the sizes of their residential buildings where livestock were raised are less than ¼ plots with limited space for both humans and animals. The distance estimate between human habitat and that of livestock animals of 70% of the farmers is less than four meters (&lt;4m) as opposed to the world standard of 50m. Findings also show that direct animal and human interaction has become a serious health issue as some effects of zoonotic diseases, which include cholera 7%, abortion 15%, diarrhea 31%, and typhoid 50%, have been mentioned among urban livestock farmers. Some of the effects were 37% land degradation, 22% deterioration of structures and 29% contamination of water, 40% noise pollution, and destruction of properties, among others. Therefore, the research recommends that livestock farmers should constitute part of the negotiation at the planning stage. Sitting and constructing sanitary landfills, monitoring the quality and nature of the groundwater reservoirs, and medical research on both the health of the animals and their owners are to be conducted by taking blood, urine, and stool samples to medical laboratories.

Detection of hydrocarbon spills by means of a coaxial impedance dielectric sensor

Leakages from storage tanks or pipes frequently produce pollution of soils and groundwater reservoirs by hydrocarbons. Common practices for monitoring and characterising site contamination involve soil drilling, sampling and chemical analysis, complemented with geophysical surveys. This study evaluates the presence of paraffin oil inside soil pores by means of dielectric permittivity measurements, using a coaxial impedance device in laboratory-scale models. The real dielectric permittivity of unsaturated sand is measured before, during and after a contamination process. Monitoring small variations in real dielectric permittivity allows detection of the partial replacement of air (κ′ = 1) by paraffin oil (κ′ ≈ 2) in soil pores. These variations in soil dielectric properties enable pollution levels to be assessed, knowing in advance the κ′ of the soil at the initial stage and measuring the influence of oil and water content on κ′. The technique proposed can also be used for monitoring the lateral extension of a contaminant plume and can be successfully applied at the laboratory scale for oil leakage detection by periodically monitoring changes in the soil dielectric permittivity.

Geysers, Boiling Groundwater and Tectonics: The 3D Subsurface Resistive Structure of the Haukadalur Hydrothermal Field, Iceland

AbstractGeysers are among the most fascinating geological features on Earth. Yet, little is still known about their hydrogeological structure at depth. To shed light on the spatial relationships between the vertical conduits and the aquifers feeding them, we conducted a 3D geoelectrical campaign in the Haukadalur hydrothermal field, Iceland. We deployed 24 Iris Fullwavers across the hydrothermal field and inverted resistivity and chargeability measurements. Additionally, we measured temperature variations inside Strokkur and Great Geysir geysers showing temperature fluctuations pointing out the oscillatory behavior that characterizes the geysering cycle of the geysers. By combining a semi‐quantitative temperature distribution of the thermal springs across the hydrothermal field with the inversion of the geoelectrical data, we highlight the control that extensional tectonics have on the distribution of fluids across the hydrothermal field. We also point out the occurrence of a common deep groundwater reservoir feeding the hydrothermal centers. Induced polarization data show that the geysers are fed by sub‐vertical water‐filled fracture zones. The geysers are found at the margins of highly resistive regions where we speculate boiling groundwater and vapor is found. Our proposed model suggests that local waters feeding the main groundwater reservoir downwell from the nearby region and then convect upwards, phase transitioning into vapor at about 200 m depth. From here, fluids flow toward the surface through pipes cutting a highly pressurized and hot system. This study shows to the best of our knowledge the first full 3D tomographic image of a hydrothermal field hosting geysers.

Combined use of statistical Bayesian model and strontium isotopes deciphering the high complexity groundwater flow in the Guarani Aquifer System (GAS)

The Guarani Aquifer System (GAS) is one of the most important groundwater reservoirs in Latin America. Even though its geological aspects and hydraulic behavior are deeply studied, questions regarding hydraulic connections between the GAS and the overlying (SGAS) and underlying (PRE-GAS) aquifers within the Paraná Sedimentary Basin geological framework are recently being pursued. This paper presents a new tracer approach within the GAS, incorporating strontium isotopes in a statistical Bayesian model. The multi-pronged approach is used to quantify mixing proportions and identify different processes related to water-rock interaction and hydrochemical data. Strontium isotopic ratio ranged from enriched values (>0.711) associated with higher GAS groundwater contribution, to lower values associated with contribution from the SGAS (∼0.707) and PRE-GAS (∼0.709) units, as well as isotopic fingerprint associated with direct rainwater recharge. As groundwater flows through the GAS, the mixing proportions between the end-members changes along with the hydrogeochemical evolution. Near recharge zones, GAS represents the dominant source (38% ± 10%), followed by PRE-GAS (28% ± 16%), SGAS (19% ± 11%) and rainwater (14% ± 10%). In transition waters between outcrop and confined areas, the GAS contribution remains dominant (48% ± 9%), followed by PRE-GAS (37% ± 14%) and SGAS (14% ± 8%). In the GAS confined zone, where contributions from rainwater and SGAS is absent, 87Sr/86Sr ratio is more associated with waters from PRE-GAS (53% ± 16%) than from GAS (46% ± 16%). This behavior indicates that groundwater flow in the GAS represent a more complex and vulnerable groundwater mixing system, closely related to the regional geological context of a closed intracratonic basin, than previously understood. The use of strontium isotopes as a hydrogeochemical tracer applied in a statistical mixing model, contributes to a more refined understanding of regional groundwater flow and water origin in the GAS.

Impacts of Climate Change on Water Resources, Agricultural Production and Food Security: Evidence from Turkiye

Since agricultural production depends mainly on nature and uses surface and groundwater reservoirs, changes in existing water resources significantly affect this sector. Again, changes in global climate bring changes in water levels, consequently affecting agriculture, food supply, and income sources of households in different areas. However, to date, no such research has investigated the farmers who are the producers and the most vulnerable group to the impacts of climate change. Therefore, this paper explores climate change impacts on the water resources of Sarayonu, which in turn affects the agricultural food production and food security of the producers' households and the country's market. This qualitative study conducted in-depth interviews with the farmers from the Sarayonu district of Konya province in Turkiye. The study results show that ground and surface water resources are negatively affected by climate change. Consequently, the study area observed a decrease in water level over the last 15 years. Thus, these changes in water resources have been significantly affecting the agriculture sector, which alters the food supply for the market in general and the producers in particular. When people have less water, they have low quality and quantity crop yields, resulting in food crises and economic difficulties.

Storage capacity of a karst groundwater reservoir associated with a large dam in a humid subtropical canyon karst area in southwestern China

Storage capacity of a karst groundwater reservoir associated with a large dam in a humid subtropical canyon karst area in southwestern China

Obliquity-forced aquifer-eustasy during the Late Cretaceous greenhouse world

The mechanisms of short-term (105–106 years) and high-magnitude (>20 m) sea-level oscillations have long been debated involving glacio- and aquifer-eustasy, largely owing to the sparse robust evidence for the presence and significance of aquifer-eustasy, and lack of knowledge about the hydrological dynamics behind it. Non-marine/continental greenhouse archives (e.g., lake level) and their temporal correlation to marine successions (e.g., sea level) could provide clues to aquifer-eustasy. The Songliao Basin (SLB) in Northeast China is one of the largest Mesozoic terrestrial inland basins and provides a terrestrial archive of nearly all Cretaceous successions. The greenhouse late Santonian–early Campanian lower Nenjiang Formation (K2n1+2), recovered from three boreholes in the SLB, provides a unique opportunity for validating and decoding aquifer-eustasy. Initially, the cyclostratigraphy of logging gamma ray (GR) and thorium (Th) series from three boreholes was implemented, which in conjunction with precise geochronological (U/Pb zircon) ages renewed the chronology framework of the SLB. Using the astronomically tuned GR and Th datasets, the lake level of the SLB, which was recovered from sedimentary noise modeling and presented as a proxy for the water table of the groundwater reservoir, showed a clear out-of-phase relationship with the coeval sea level, validating the aquifer-eustasy hypothesis. The lake level of SLB shows prominent ∼1.2 Myr cycles and a well-coupled relationship with sea level and obliquity modulation, indicating that orbital obliquity drove the lake level and modulated water exchange between ocean and continent during the Cretaceous greenhouse period. Strong precipitation events indicated by negative excursions of ostracod δ18O correlate well with high lake levels, high obliquity, and low sea level, suggesting that more moisture was precipitated into the high-latitude continents during obliquity modulation maxima, consequently recharging the aquifer and raising the lake level while drawing down the sea level and vice versa. The close correlation between the reported marine incursion layers and the lowstand of sea level casts a doubt on the marine incursion hypothesis in the SLB; thus, more work is needed to reconcile this paradox. Overall, this study provides the first robust geological evidence for aquifer-eustasy and decodes its role in Cretaceous short-term eustasy.

The Water Budget Myth and Its Recharge Controversy: Linear vs. Nonlinear Models.

The water budget myth, which is the idea that safe pumping must not exceed the initial recharge, gave rise to a controversy about the role of recharge in assessing the sustainability of groundwater development. To refute the concept of safe yield, a simplified water budget equation is used, which equals the total pumping rate to the sum of capture and storage change. Since initial recharge and discharge are canceled out from this equation, it is concluded that sustainable pumping has nothing to do with recharge. Investigating the assumptions underlying this equation, it is seen that it expresses the superposition principle, which implicitly assumes the groundwater reservoir can be depleted indefinitely and boundary conditions are an infinite source of water. To evaluate sustainability, however, the limits of the aquifer system must be examined accurately. Theoretically, this can only be accomplished applying nonlinear models, in which case setting up the simplified water budget equation is impossible without knowing the initial conditions. Hence, excluding recharge when assessing sustainable pumping may not be done inconsiderately, which is illustrated by two examples. An analytical solution, developed by Ernst in 1971 to simulate flow to a well in a polder area with a nonlinear function for drainage, even shows that it is not necessarily a misconception to assume the cone of depression stops expanding when the pumping rate is balanced by the infiltration rate.

Deep aquifers as strategic groundwater reservoir in Spain

The objective of this paper is to establish a definition of deep aquifers, develop a methodological proposal to help select them as strategic groundwater reserves and develop a first inventory of deep aquifers in peninsular Spain, organized by hydrographic districts. The basic premises followed to consider a permeable formation as a deep aquifer are: water table depth greater than 300 m in free aquifers or the top of the permeable formation in the case of confined aquifers. A deep aquifer is also considered to be the lower horizon of very thick aquifers (from 300 m), from which the most superficial horizon is used. The definition of the potentially favorable areas and the initial characterization is based on a compilation and synthesis of geological and hydrogeological information, structured in 5 large blocks: location and identification, geology, hydrogeology, current status and bibliography. For its evaluation, a flowchart has been proposed with the basic lines of the evaluation process. The relevant aspects for suitability would be: stratigraphy and structural geology, prior knowledge of the conceptual model and water renewal, quality, viability of exploitation, effects, final knowledge, and management and governance. The final result allows the aquifer to be classified into three categories: strategic groundwater reserve, punctual reserve or non-viable reserve. The inventory carried out encompasses a total of 64 deep aquifers located in 13 basin districts. Finally, as example, three deep aquifers are presented: Amblés Valley, Madrid detritic aquifer and El Maestrazgo.

Kinematics of fault-propagation folding: Analysis of velocity fields in numerical modeling simulations

Fault-propagation folding occurs when a shallow fold is created by an underlying propagating thrust fault. These structures are common features of fold and thrust belts and hold key economic relevance as groundwater or hydrocarbon reservoirs. Reconstructing a fault-propagation fold is commonly done by means of the trishear model of the forelimb, a theoretical approach that assumes simplistic rheological rock properties. Here we present a series of numerical models that elucidate the kinematics of fault-propagation folding within an anisotropic sedimentary cover using complex visco-elasto-plastic rheologies. We explore the influence of different parameters like cohesion, angle of internal friction, and viscosity during folding and compare the velocity field with results from the purely kinematic trishear model. In the trishear paradigm, fault-propagation folding features a triangular shear zone ahead of the fault tip whose width is defined by the apical angle that in practice serves as a freely tunable fitting parameter. In agreement with this framework, a triangular zone of concentrated strain forms in all numerical models. We use our models to relate the apical angle to the rheological properties of the modeled sedimentary layers. In purely visco-plastic models, the geometry of the forelimb obtained can be approximated using a trishear kinematic model with high apical angles ranging between 60° and 70°. However, additionally accounting for elastic deformation produces a significant change in the geometry of the beds that require lower apical angles (25°) for trishear kinematics. We conclude that all analyzed numerical models can be represented by applying the theoretical trishear model, whereby folds involving salt layers require high apical angle values while more competent sedimentary rocks need lower values.

Investigation of water recovery from sewage using solar thermal technology

The availability of potable water for human use, agriculture, and industrial usage is a major challenge both in undeveloped and developing countries. Water, like food and air, is considered essential for human survival, and the majority of people rely on untreated water from rivers, lakes, and groundwater reservoirs. Oceans are the only place where enormous amount of water is found and desalination of the water is needed because they consists high levels of salt. But, the increase in population, urbanization and industrialization resulted in higher release of sewage and industrial effluents into water bodies and subsequent water pollution. It results in a scarcity of pure water in many towns and villages, despite their proximity to lakes and rivers. Water scarcity is anticipated to worsen in the next years, with the majority of the world’s population experiencing it in the near future. Potable water is essential not just for survival, but also for industrial and agricultural processes. Physical, chemical, and biological processes are normally used to remove contaminants from wastewater and produce pure water. In this context, an attempt is made in this paper to use the concept of solar still for sewage treatment. The experimental setup was created to examine the performance of a solar still with an evaporator and condenser. The results revealed that combining a heater and a condenser with a pyramid solar system enhanced solar still production by 4 to 8 l/Sq.m/day when using saline water, 4 to 7 l/Sq.m/day when using sewage water, and 3 to 6 l/Sq.m/day when using effluent water.

Hiied vee veerel. Pärimuse ja maastiku kujundikeelest looduslikes pühapaikades

In addition to religious content layers, the word hiis (holy grove) seems to express also certain features of a natural landscape. The article discusses the issues concerned with the location of hiis areas as well as their meaning. There are signs of links between ‘holy’ and ‘hiis’ that can be traced in the toponymy observed in both lore and maps, although it is not always that place lore or placenames have survived in written form until today. The main emphasis in the article is placed on the water element related to holy groves, waterbodies and springs as well as wetlands. Often the holy grove is situated at a watershed or headspring, next to springs, the mouth of a river or a stream, a (former) larger waterbody or karst area. Water connects many places, and holy places can often be found in the marginal areas or junctions of waterbodies. In the case of water and presumably also holy places, place lore seems to consider as essential the ability to move in different ways and change the shape – this is reflected, for example, in legends about travelling nature objects as indicators of holiness. On occasion, the hiis areas mark natural reservoirs of clean groundwater; this is essential to acknowledge as the issue of water still occupies a crucial role among other environmental problems. So the stereotype of hiis as a holy grove, so-called Taara oak grove, embodies remarkably broader possibilities for interpreting the holiness of places in today’s context, for valuing these places and protecting them both culturally and environmentally.