Seepage Water Research Articles

Post-Earthquake Survey of Bagmati River Seepage Through Physicochemical Analysis of Water

Bagmati river has a great cultural, economic and mythological significance. It has also been related to the civilization of Kathmandu valley. Due to the rapid and unmanaged urbanization and industrialization the river has been heavily polluted leading to the water borne hazards and water shortage problem in the capital. Amidst this problem there was a major earthquake in Kathmandu in 2015 which disturbs the land masses in the valley. This research was conducted to assess the physico-chemical parameters of Bagmati river water and ground water from its corridor at about 50 m and 100 m distance for comparison to detect the post-earthquake seepage status of river water from October 2019 to March 2020. In total 10 sites (A-J) were selected from Gokarna to Chovar. From each site 1 river and 2 ground water samples at approximately about 50 m and 100 m radial distance from river were taken. The range of temperature, turbidity, conductivity, TDS, pH, chloride, total hardness, total acidity, total alkalinity, total iron content, total ammonia content, dissolved oxygen content and biochemical oxygen demand (BOD) were recorded to be 13-22 ºC, 150.5-395.5 NTU, 121.1-825 μs/cm, 77.56-528 ppm, 6.5-7.84, 4.97-114.3 mg/l, 34-180 mg/l, 10-224 mg/l, 70-382 mg/l, 0.55-4.156 mg/l, 5-150 mg/l, 0-4.5 mg/l and 5.35-320 mg/l respectively for river water samples and 16-21 ºC, 3.8-52.1 NTU, 25.2-745 μs/cm, 16-476.8 ppm, 6.08-7.61, 5.68-134.9 mg/l, 6-328 mg/l, 10-140 mg/l, 30-340 mg/l, 0.02-5.101 mg/l, 0.026-0.9 mg/l, 2.63-8.1 mg/l and 1.62-16.3 mg/l respectively for ground water samples at 50 m distance from river and 16-20 ºC, 3.1-60 NTU, 25.6-697 μs/cm, 12.8-446.08 ppm, 5.49-8.78, 5.68-44.02 mg/l, 10-300 mg/l, 10-160 mg/l, 14-294 mg/l, 0.015-4.37 mg/l, 0.028-0.54 mg/l, 3.1-8.7 mg/l and 0.63-14.2 mg/l respectively for ground water samples at 100 m distance from the river. As there were significant differences in turbidity, chloride, total acidity, iron, ammonia and BOD among Bagmati and ground water samples, direct mixing of polluted Bagmati river water with nearby ground waters through seepage was not detected. Thus, irrespective of earlier condition, the land masses near the Bagmati territory has not been affected so as to allow deeper seepage of river water by the earthquake of 2015.

Monitoring Water Depth and Seepage Rates in Pitcher Irrigation for Sustainable Crop Water Management

Pitcher irrigation is an ancient yet effective method for delivering water directly to plant root zones, particularly in regions facing water scarcity. The main objective of this study is to evaluate the efficiency of pitcher irrigation in conserving water and supporting brinjal crop growth. This study investigates the efficiency and dynamics of a pitcher irrigation system in supplying water to brinjal crops, utilizing nine porous clay pitchers buried near the plants. Water depth in the pitchers was monitored from March 1 to March 22, 2024, at three intervals daily. Initial water levels of 15 cm were recorded on March 1, followed by gradual declines in water depth over time, with some pots showing rapid depletion, particularly during peak daylight hours. Pot 4 exhibited the most significant water loss, likely due to increased soil absorption or higher crop water demand, while Pots 1 and 3 showed more consistent water retention. The study revealed significant variation in seepage rates, with higher water loss during the day, particularly in the afternoon, compared to slower overnight seepage. These findings emphasize the need for careful irrigation management, including tailored refill schedules, to ensure uniform water availability and prevent moisture deficits. The results demonstrate that pitcher irrigation can effectively sustain crop growth, but its efficiency depends on continuous monitoring and adjustments based on local conditions.

2D Transdimensional Joint Inversion of Radio Magnetotelluric and Electrical Resistivity Tomography Data

Summary The joint inversion of radio magnetotelluric and electrical resistivity tomography data has the potential to reduce the uncertainties in the subsurface conductivity model. This is particularly beneficial when the datasets offer complementary information about the subsurface. However, the traditional gradient-based inversion methods pose challenges in quantifying uncertainty, as they yield a single model with limited appraisal of parameter uncertainty. The Bayesian inversion approach stands out for its capacity to provide quantitative assessments of uncertainty in the inverted model parameters. This is accomplished by generating an ensemble of models, leading to a posterior distribution that encapsulates both prior information concerning model parameters and the dataset information. We have implemented a transdimensional Markov chain Monte Carlo algorithm to perform the joint inversion of radio magnetotelluric and electrical resistivity tomography data. Through synthetic data studies, we illustrate how the inclusion of two complementary datasets can effectively reduce uncertainties in model parameters and how the model parameter uncertainties can be quantified. Subsequently, the developed algorithm is tested using exemplary field data from a waste site near Roorkee, India. Intensive prior geoelectric and transient electromagnetic as well as radio magnetotelluric studies investigated possible waste water seepage with a potential to contaminate the shallow aquifers. The derived subsurface structure from our transdimensional Bayesian results compare well with the deterministic results for the exemplary profile, but in addition provide comprehensive uncertainty estimates.

REPAIR OF PORTICO ELEMENTS AND DRAINAGE SYSTEM OF THE HUSEJNIJA MOSQUE IN GRADAČAC

In 2004, the Commission for the Preservation of National Monuments declared the "Architectural Complex of Husejnija (Husein-kapetan Gradaščević) Mosque in Gradačac" a national monument of Bosnia and Herzegovina. The mosque belongs to the type of central domed mosque with a portico covered by three small domes. In September/October 2023, cracks were observed on six arches, the capitals of two columns, and the base of one column in the portico of the mosque. Geotechnical investigative works included the creation of three excavations and two boreholes with continuous Standard Penetration Tests (SPT). The excavations reveal layers below the ground level, consisting of a well-bound sandy artificial fill from the ground surface to a depth of 1.35 meters, a layer of poorly bound artificial stony material from 1.35 to 2.45 meters, and a layer of natural clay at greater depths. It is assumed that over time, due to water seepage from the hillside and rainfall runoff from the mosque, there has been a change in the physical-mechanical properties of the foundation soil and partial settling of the portico structure. In addition to the existing channel on two sides of the mosque, a drainage ring around the building and a drainage curtain on the uphill slope have been designed. Also, underpinning of the portico foundations in alternating segments has been designed to strengthen the stone masonry layer and prevent further settling and development of cracks in the portico elements. After the works are completed, a 12-month monitoring period is planned, followed by an analysis and repair of the cracks.

Fluorescence visualization dynamics of carbonated water injection processes in homogeneous glass micromodels

Understanding the flow behavior of oil–water phases in porous media is crucial for revealing the kinetic mechanisms underlying oil–water movement. In this study, we designed and constructed a fluorescence visualization experimental platform for carbonated water injection (CWI). We evaluated the effects of nine distinct injection rates on oil production and CO2 sequestration capabilities using three types of homogeneous porous structure micromodels. The microscale oil–water seepage behavior at the pore scale was also explored. The experimental results indicate that optimally increasing the injection rate can improve displacement efficiency, whereas excessively high rates may lead to viscous and capillary fingering. The geometry of the micromodels, particularly the hexagonal matrix, demonstrates potential advantages in enhancing oil displacement due to its uniform flow paths. The capillary number (Ca) significantly influences oil droplet capture behavior within micromodels. For instance, micromodel A captures the largest ganglion area at low Ca values, with a noticeable reduction in average ganglion area as Ca increases. Conversely, micromodels B and C exhibit similar trends in ganglion size variation at high Ca values, suggesting a more uniform impact of pore structure on oil droplet capture behavior. At elevated Ca values, capillary forces exert a more uniform and controlled effect on oil droplet capture and release, minimizing size variability. Additionally, the injection rate plays a critical role in CO2 sequestration, with higher rates promoting convective mixing between CO2 and reservoir fluids, thereby enhancing dissolution and storage efficiency. The complexity of the pore structure, characterized by the presence of micropores and macropores, affects the dissolution kinetics and mobility of CO2, influencing sequestration efficiency. These experimental findings provide valuable insights into the dynamics of oil–water motion and the potential for enhanced oil recovery (EOR) and CO2 storage, offering essential guidance for optimizing CWI strategies in the petroleum industry.

Insight into failure mechanisms of rainfall induced mudstone landslide controlled by structural planes: From laboratory experiments

The role of structural planes in controlling mudstone landslides is a key issue in the study of the geo-disasters in the Loess Plateau of China. In this study, the effects of sliding-control structures on the mechanisms of mudstone landslides are investigated via three model experiments with different slope structures. The results show that the hydrological response and failure mode of the experimental slope vary with the structural conditions. The vertical joints serve as preferential seepage paths, which accelerate rainfall infiltration, resulting in earlier responses of volumetric water content and pore water pressure. With the incorporation of vertical joints, the slope failure mode tends to transform from shallow failure to deep-seated failure. The presence of a weak interlayer leads to significant increases in the velocity and runout of the sliding mass. The variation in the slope failure extent and deformation characteristics with varying sliding-control structures further changes the temporal and spatial distributions of volumetric water content and pore water pressure. The different slope failure modes correspond to different sliding-control mechanisms, which are dominated by the types of structural planes and their interactions with hydrological responses. In the action of these mechanisms, pore water pressure and seepage force play significant roles in the reduction of effective stress and shear strength.

Invasion Characteristics of Marginal Water under the Control of High-Permeability Zones and Its Influence on the Development of Vertical Heterogeneous Gas Reservoirs

In-depth understanding of the gas–water seepage law caused by different degrees of gas layer perforation and varying gas production rates is key to determining a reasonable development technology policy for vertical heterogeneous edge-water gas reservoirs. Based on core physical data from the entire section of the X2 well, a large-scale high-pressure positive-rhythm profile model that takes into account the influence of “discontinuous interlayer” was innovatively established. The water intrusion process of the gas layer profile under different gas production rates and degrees of gas layer perforation was simulated using an electrical resistivity scanning device. The experimental model has an area of 3000 cm2, with a maximum pressure of 70 MPa and a maximum temperature resistance of 150 °C. It includes 456 evenly distributed fluid saturation test points to accurately monitor the gas–water distribution, addressing the issues of small bearing pressure and insufficient saturation monitoring points found in other large-scale models. The experimental results show that, in heterogeneous reservoirs, the high-permeability zone controls the invasion path of edge water, which is the main reason for the uneven invasion of edge water. For the positive-rhythm profile of the F layer, a higher gas production rate (1000 mL/min) shortens the water-free gas recovery period of the gas well and reduces the recovery rate. Perforating the upper two-thirds of the layer can inhibit edge-water breakthrough, prolong the water-free gas recovery period of the gas well, enable the gas–water interface to advance more uniformly, and enhance the recovery degree. The results of this study greatly enhance our understanding of the water invasion characteristics of positive-rhythm reservoirs under the influence of different gas production rates and varying degrees of gas layer perforation.

Experimental and Numerical Study on Lightweight-Foamed-Concrete-Filled Widened Embankment of High-Speed Railway.

To study the performance of lightweight foamed concrete (LWFC) in widened embankments of high-speed railways, this study first conducted numerous strength, permeability, and water immersion tests to investigate the mechanical properties and water resistance of LWFC with designed dry densities of 550, 600, and 650 kg/m3. Secondly, a field test was performed to analyze the behavior of the deformation and the internal pressure within the LWFC-filled portions. Furthermore, a parametric study via numerical modeling was performed to investigate the effects of four key factors on the performance of the LWFC-filled, widened embankments. Results showed that LWFC possesses adequate bearing capacity and impermeability to meet high-speed railway embankment widening requirements. However, water seepage reduces LWFC strength. The additional pressure from LWFC filling increases initially but then decreases once dehydration occurs. The settlement induced by LWFC accounted for 71% of the total filling height, which is only 37.5% of the total settlement after construction. The parametric study results show that the maximum settlement of widened and existing portions induced by LWFC was 46.3-49.6% and 48.3-53.2% of those induced by traditional fillers due to the LWFC's lower density as well as their better self-supporting ability. Making an appropriate reduction in the thickness of the retain wall installed against the LWFC-filled widened embankment of the high-speed railway generates a few variations in the lateral deformation of the wall. Furthermore, the effects of the pile offset on the deformation of the LWFC-filled embankment were more sensitive compared to the diameter of the piles.

Alkali-activated materials containing mine tailings and zeolite for seepage water treatment in a closed nickel mine

AbstractIn the present study, alkali-activated materials were assessed as adsorbents for mine water treatment. The composition of alkali-activated materials, involving mixtures of metakaolin, blast-furnace slag, mine tailings, and zeolite, was optimized based on their leaching behavior and adsorption performance. The most effective adsorbent contained solely blast furnace slag as an aluminosilicate precursor and was selected for a pilot-scale study at a closed nickel mine in Finland. In the pilot, seepage water from a gangue area with an influent flow rate of 0.5 m3/d was treated using a permeable reactive barrier set-up containing 10 kg of slag-based adsorbent prepared by a granulation-alkali activation process. During a one-week experiment, the adsorbent granules were capable of effectively uptaking Ni, Fe, and Mn from the seepage water; the removal percentages of Ni, Fe, and Mn were 82.4%, 81.6%, and 82.5%, respectively. The results indicated the feasibility of blast furnace slag-based adsorbents for toxic element removal in a potentially sustainable approach.

Different Quality Index of Irrigation Water From canal of Sone River

The purpose of this research was to examine the Different quality index of irrigation watercanal of Sone river. A canal is a man-made waterway dug to provide farms with irrigation supplies. Thewater is obtained from a lake, pond, river, or reservoir. In order to combat water erosion and seepage,canals may be constructed from concrete, brick, or a flexible stone. Irrigating land using a canal andassociated irrigation system is a time-tested and cost-effective strategy. The height of the water canalintake diagrams. Irrigation systems in fields rely on water drawn from reservoirs, such as ponds andreservoirs, or river wells, which are pumped to the fields.

Frequency Analysis of Annual One Day Maximum Rainfall at Faisalabad, Lahore and Multan (Punjab)

Effective management of water systems and seepage projects depends on accurate precipitation data, particularly annual daily maximum precipitation, which is essential for designing hydraulic structures. This study conducts a frequency analysis of annual daily maximum precipitation for Faisalabad, Lahore, and Multan in Punjab, Pakistan, using over 50 years of historical data from these three stations. The analysis, performed with RAINBOW software, evaluates five probability distributions—normal, log-normal, weibull, gamma, and exponential. The fit of these distributions was assessed using Chi-square, Kolmogorov-Smirnov, and Anderson-Darling tests at significance levels of 5%, 10%, and 20%. Results indicate that the Weibull and Log-normal distributions most accurately represent the precipitation data. Based on this analysis, the study estimates the magnitude of maximum annual precipitation for return periods of 2, 5, 10, 25, 50, and 100 years. The findings aim to improve water management strategies, enhance flood and drought prevention measures, and optimize the hydraulic design of seepage structures, contributing to more effective planning and resilience in the face of extreme weather events.

Unveiling vertical migration patterns of the mesopelagic fish Ceratoscopelus warmingii in cold seep ecosystems: A trophic niche perspective

Ceratoscopelus warmingii, a common mesopelagic fish in cold seep ecosystems, plays a crucial role in transferring energy and materials between different water layers, thereby influencing deep-sea carbon cycling and storage. In August 2023, we collected samples from four depths (75 m, 400 m, 500 m, and 600 m) in cold seep waters to analyze the trophic niche characteristics of C. warmingii using stable isotope techniques. The results indicated significant differences in δ13C and δ15N values among the water layers, with mean δ13C and δ15N values of −19.85 ‰±0.33 ‰ and 8.41 ‰±0.62 ‰, respectively. Indicators of trophic structure showed distinct vertical differentiation, with the width of the trophic niche decreasing as depth increased. At 75 m and 400 m, the consistency of CR and NR indicators and high trophic niche overlap indicated similar food sources, confirming vertical migration behavior. In contrast, at 500 m, the MNND and SDNND values suggested a more stable trophic structure, while at 600 m, changes in feeding sources pointed to a distinct population. The Standard Ellipse Area of Overlap (SEAc) was highest between 75 m and 400 m, while the divergence of trophic ecological niches at 600 m, with different food sources, suggests that cold seep ecosystems at this depth provide a relatively stable trophic structure for C. warmingii and support the formation of an independent population. In cold seep ecosystems, C. warmingii employs adaptive trophic strategies to optimize survival under varying habitat conditions at different depths. This vertical trophic differentiation reduces intraspecific competition and enhances population stability in deep-sea habitats. This study enhances our understanding of the trophic niche and vertical migration of C. warmingii in cold seep ecosystems, significantly contributing to our knowledge of biodiversity, energy flow, and material cycling in these unique environments.

Enhancing Dam Safety: Statistical Assessment and Kalman Filter for the Geodetic Network of Mosul Dam

Dams play a pivotal role in providing essential services such as energy generation, water supply, and flood control. However, their stability is crucial, and continuous monitoring is vital to mitigate potential risks. The Mosul Dam is one of the most interesting infrastructures in Iraq because it was constructed on alternating beds of karstified and gypsum which required continuous grouting due to water seepage. Therefore, the ongoing maintenance issues raised international concerns about its stability. For several years the dam indicated a potential for disastrous failure that could cause massive flooding downstream and pose a serious threat to millions of people. This research focuses on comprehensive statistical assessments of the dam geodetic network points across multiple epochs of long duration. Through the systematic application of three statistical tests and the predictive capabilities of the Kalman filter, safety and long-term stability are aimed to be enhanced. The analysis of the dam’s geodetic network points shows a consistent trend of upstream-to-downstream movement. The Kalman filter demonstrates promising outcomes for displacement prediction compared to least squares adjustment. This research provides valuable insights into dam stability assessment, aligns with established procedures, and contributes to the resilience and safety of critical infrastructure. The outcome of this paper can encourage future studies to build upon the foundation presented.

Revealing the mechanisms of water permeability enhancement of urban loess subgrades due to vibration application

Urban loess subgrades are affected by considerable vibrations from traffic, especially when the underground pipelines leak, and seepage under vibrations often causes road damage. However, the influence of vibrations on the water permeability of loess subgrades remains elusive. Here we address this issue by performing vibration-assisted permeability tests and scanning electron microscopy, mercury intrusion porosimetry, and suction–nuclear magnetic resonance measurements. This allowed the evolution of the saturated hydraulic conductivity (Ks), water-air migration, soil microstructure, and pore water forms to be evaluated. The water permeability of the loess subgrade is promoted by vibrations due to the increase in Ks, the acceleration of wet front migration, and the escape of entrapped air. Moreover, the value of Ks under vibration is 3–14 times greater than that without vibration, and the maximum increase occurs at a vibration frequency near the natural frequency of the loess. Furthermore, a theoretical framework of loess vibration permeability is proposed, and the mechanisms by which vibration accelerates the permeability behavior of the loess subgrade are revealed. Vibration promotes the expansion of soil pores, a decrease in the binding capacity of pore water, the mobilization of fine particles, and the formation of local low-permeability layer. Moreover, it accelerates the opening of entrapped air bubbles and the displacement of water-air, the reduction in seepage resistance. Thus, seepage water flows rapidly along infiltration channels. These findings are highly important for the road safety performance and the sustainable development of the traffic environment in loess regions.

Dynamic response of seabed in wind power of deep-shallow sea induced by internal solitary waves

With the development of offshore wind power projects worldwide, the stability of deep and shallow sea wind power sites has become a crucial concern. Internal solitary waves (ISWs) are nonlinear and large amplitude waves in the stratified ocean. Their strong vertical and horizontal motion and vorticity and turbulence caused by fragmentation have an important impact on the marine environment, seabed sediments, and marine engineering. This study focuses on the interaction between ISWs and the seabed of wind power sites in deep and shallow seas. Specifically, we investigate the interaction between ISWs and monopile foundations or floating fan plate anchor structures in the seabed. Through the simulation of CFD software and Comsol software, a law of seabed pore pressure variation during the effect of ISWs on the structure can be well demonstrated. Our results demonstrate that ISWs induce the accumulation of excess pore water pressure around the structures. The monopile foundation experiences negative excess pore water pressure at its bottom and the plate anchor at its top. The pore water pressure at the bottom of the monopile foundation initially decreases and then increases. In contrast, the pore water pressure at the right side of the monopile foundation increases, decreases, and then increases. This phenomenon promotes the settlement of the structure. At the bottom of the plate anchor, there is a sharp increase in positive excess pore water pressure by ISW. The pore water pressure above the plate anchor structure initially decreases and then increases, while below the plate anchor, it increases and then decreases. This phenomenon leads to the movement of the anchorage structure and instability of the surrounding soil. The influence of ISWs on the seabed bottom intensifies with the obstruction of the structure, resulting in significant positive pressure at the bottom. Between the two anchoring structures, there is increased seepage of pore water, making the seabed more prone to instability. Through the study of this article, we know that ISW has different effects on the force of monopile foundation and plate anchor structure, which provides a favorable basis for its design and maintenance.

Preparation and properties of an anti-icing and de-icing emulsified asphalt coating containing RTV and CNTs

In regions experiencing cold weather, road icing poses significant challenges to transportation safety. Traditional anti-icing or de-icing methods, such as salt spraying, have raised environmental concerns, prompting the exploration of more sustainable alternatives. This study introduces a novel approach by developing a hydrophobic coating for road surfaces. This method involves using room-temperature vulcanized silicone rubber (RTV) and carbon nanotubes (CNTs) for the hydrophobic modification of emulsified asphalt (EA), resulting in the preparation of modified emulsified asphalt (RCEA). This method does not cause environmental pollution and makes the road surface highly hydrophobic and effective at preventing ice formation. When the dosages of RTV and CNTs are 20 wt% and 4 wt%, respectively, the contact angle of RCEA reaches 118.6°, showing a significant increase of 73.4 % compared to EA. Comparative tests have revealed that RCEA extends the freezing time of water droplets by 66.7 % at −10 °C compared to traditional emulsified asphalt (EA). Furthermore, the adhesion force of ice on the RCEA surface is 58.2 % lower than on EA, indicating significantly improved de-icing efficiency. The results of ultraviolet aging and freeze-thaw cycle tests show that RCEA maintains its hydrophobicity, evidenced by only a slight reduction in the contact angle. Additionally, water seepage coefficient tests and anti-skid performance assessments confirm that RCEA meets the requisite standards for road performance. In summary, RCEA emerges as a promising anti-icing and de-icing material for asphalt roads, offering an environmentally friendly alternative to traditional de-icing methods.

Analysis of water inrush of a deep excavation triggered by river bank failure and its reconstruction

Many deep excavation projects are adjacent to river, and hence face the seepage risk. In this study, a through-wall seepage failure of a foundation pit adjacent to river is investigated. It is found that, the accident was initiated by the breakage of revetment along the construction joint and cracks of rubble stone masonry, which further caused the slope failure of river bank and the subsequent seepage of river water through the cold joint of waterproof curtain. The remedial works including construction of cofferdam in the river, backfill outside the foundation pit, reinforcement of cold joint, backfill inside the foundation pit, controllable dewatering outside the foundation pit and axial force adjustment of struts are designed. The monitoring results indicate effective implementation of the remedial works and the following successful reconstruction of the project. A summary of reported seepage failure cases adjacent to river is finally made to provide suggestions for the design and construction of future similar deep excavation projects.

Kontribusi Nilai Islam Pada Program Instalasi Pengelolaan Air Limbah Berbasis Masyarakat Di Lingkungan 01 Kelurahan Tanah Seribu

Disposal of waste water which is a basic sterilization to oblige the kitchen to waste water and other waste. Seepage water drainage channels are very important, because waste water drainage channels can also limit the spread of disease to the local area. The aim of this research is to see the contribution of Islamic values ​​to the community-based wastewater management installation program in the 01 Tanah Seribu Village environment. This research uses a qualitative research method with a descriptive approach. Results of research on Islamic quality commitment to regional-based water waste by implementers of climate development programs in Tanah Seribu District 01, with details: 1) Viability is considered not yet ideal because the implementation of water content quality testing is not optimal because it does not pay attention to needs and the KPP's lack of attention to support WWTP. 2) The productivity of IPAL construction is considered large because it receives financial assistance from the APBN. However, functional expenditure is not yet ideal due to low regional support. 3) The arrangement should be ideal considering that the benefits of the program are mostly felt by the local area. 4) Adequacy is ideal because the IPAL program has many benefits. 5) Responsiveness regarding public reactions is considered certain, but open attitudes are still lacking. 6) Precision is not in accordance with Islamic qualities because there is no public awareness, but it is considered ideal because it tends to be the answer to the defeat of the water waste problem. Based on Islamic values, it can be concluded that the IPAL program in Environment 01, Tanah Seribu Subdistrict is in line with Islamic values ​​as seen in terms of environmental cleanliness which is increasingly maintained. However, on the other hand, community participation is still less than optimal in being responsible for protecting and preserving the environment.

Temporal evolution of fracture transport properties of fractured shales during long-term stress compaction

Understanding the temporal evolution of fracture transport properties in shales is of increasing importance for the long-term safe operation of many underground engineering projects. Here, a series of long-term (60 days each) water seepage and gas breakthrough experiments utilizing three shale samples, each with a single artificial fracture, was conducted to evaluate the time-dependent evolution of permeability and gas breakthrough pressure (GBP) under constant confining stress. Our results show continuous decreases in permeability and increases in GBP with time, and the rate of change in both is initially rapid but then slows. As the loading time increases, the permeabilities and GBPs become relatively constant. The inferred mechanisms are aperture reductions caused by mechanical creep and clay swelling of fractures. Pretest and posttest scans of fracture surfaces reveal some changes in asperity height, which demonstrates the occurrence of mechanical damage to the fracture during the experiments. Long-term stress compaction causes flow channels to narrow or even partially close over time. The fluid flow in confined fracture is controlled by some narrow apertures in the flow channels, which act as bottleneck points. The apertures at these points decrease to the micro-nano level under stress, significantly reducing fracture transport properties. While the fracture transport properties of fractured shale obviously decrease during long-term stress compaction, residual fracture voids still dominate the fluid flow over a longer period, and are especially prone to gas escape.

Characterization and stable isotopic fingerprinting of mine seepage in hyperarid environments: An example of the Namib Lead & Zinc mine, Namibia

Mine drainage at the Namib Lead & Zinc mine in the hyperarid environment of the Namib Desert close to Swakopmund, Namibia, has been investigated using mineralogical, hydrochemical, and isotopic methods. The principal ore minerals are galena and sphalerite. Mine drainage is neutral due to the reactions with the marble gangue rock. Mine water seepage is of the Na-Ca-Cl-SO4 type and sources of dissolved ions are likely halite and gypsum in the unsaturated zone above the mine. Concentrations of dissolved metals are relatively low, and the principal attenuation mechanism of metals is probably their adsorption on ferric minerals because equilibrium of the seepage water with secondary minerals that host the metals is not attained. Based on strongly enriched δ2H (up to 13.27 ‰) and δ18O (up to 4.5 ‰) values, seepage water originates from advective fog and is strongly evaporated after the fog deposition. The high δ13C(DIC) values indicate equilibrium with carbonates and CO2 de-gassing. The δ34S(SO4) values are enriched in shallower depths, probably because of pedogenic gypsum dissolution and then the δ34S values decrease with depth, probably due to the increasing input of sulfur from sulfides. Mine drainage at the Namib Lead & Zinc mine does not represent any risk for the environment due to its neutral character and relatively low seepage water volumes caused by high degree of aridity.