Search Results (535)

Floods are natural hazards that have the greatest socioeconomic impact worldwide, given that 23% of the global population live in urban areas at risk of flooding. In this field of research, the analysis of flood risk has traditionally been studied based mainly on approaches specific to civil engineering such as hydraulics and hydrology. However, these patterns of approaching the problem in research seem to be changing in recent years. During the last few years, a growing trend has been observed towards the use of methodology-based approaches oriented towards urban planning and land use management. In this context, this study analyzes the evolution of these research patterns in the field by developing a bibliometric meta-analysis of 2694 scientific publications on this topic published in recent decades. Evaluating keyword co-occurrence using VOSviewer software version 1.6.20, we analyzed how phenomena such as climate change have modified the way of addressing the study of this problem, giving growing weight to the use of integrated approaches improving territorial planning or implementing adaptive strategies, as opposed to the more traditional vision of previous decades, which only focused on the construction of hydraulic infrastructures for flood control. Full article

Small reservoirs have important functions, such as water resource guarantee, flood control and drought resistance, biological habitat and maintaining regional economic development. In order to better clarify the impact of agricultural activities on the nutritional status of water bodies in small reservoirs, zooplankton were quantitatively collected from four small reservoirs in the Jiuxianshan agricultural area of Qufu, Shandong Province, in March and October 2023, respectively. The physical and chemical parameters in sampling points were determined simultaneously. Meanwhile, water samples were collected for nutrient salt analysis, and the eutrophication of water bodies in four reservoirs was evaluated using the comprehensive nutrient status index method. The research found that the species richness of zooplankton after farming (100 species) was significantly higher than that before farming (81 species) (p < 0.05). On the contrary, the dominant species of zooplankton after farming (7 species) were significantly fewer than those before farming (11 species). The estimation results of the standing stock of zooplankton indicated that the abundance and biomass of zooplankton after farming (92.72 ind./L, 0.13 mg/L) were significantly higher than those before farming (32.51 ind./L, 0.40 mg/L) (p < 0.05). Community similarity analysis based on zooplankton abundance (ANOSIM) indicated that there were significant differences in zooplankton communities before and after farming (R = 0.329, p = 0.001). The results of multi-dimensional non-metric sorting (NMDS) showed that the communities of zooplankton could be clearly divided into two: pre-farming communities and after farming communities. The Monte Carlo test results are as follows (p < 0.05). Transparency (Trans), pH, permanganate index (COD_Mn), electrical conductivity (Cond) and chlorophyll a (Chl-a) had significant effects on the community structure of zooplankton before farming. Total nitrogen (TN), total phosphorus (TP) and electrical conductivity (Cond) had significant effects on the community structure of zooplankton after farming. The co-linearity network analysis based on zooplankton abundance showed that the zooplankton community before farming was more stable than that after farming. The water evaluation results based on the comprehensive nutritional status index method indicated that the water conditions of the reservoirs before farming were mostly in a mild eutrophic state, while the water conditions of the reservoirs after farming were all in a moderate eutrophic state. The results show that the nutritional status of small reservoirs in agricultural areas is significantly affected by agricultural activities. The zooplankton communities in small reservoirs underwent significant changes driven by alterations in the reservoir water environment and nutritional status. Based on the main results of this study, we suggested that the use of fertilizers and pesticides should be appropriately reduced in future agricultural activities. In order to better protect the water quality and aquatic ecology of the water reservoirs in the agricultural area. Full article

Capturing CO₂ emitted by coal chemical enterprises and injecting it into oil reservoirs not only effectively improves the recovery rate and development efficiency of tight oil reservoirs in the Ordos Basin but also addresses the carbon emission problem constraining the development of the region. Since initiating field experiments in 2012, the Ordos Basin has become a significant base for CCUS (Carbon capture, Utilization, and Storage) technology application and demonstration in China. However, over the years, projects have primarily focused on enhancing the recovery rate of CO₂ flooding, while issues such as potential reservoir damage and its extent have received insufficient attention. This oversight hinder the long-term development and promotion of CO₂ flooding technology in the region. Experimental results were comprehensively analyzed using techniques including nuclear magnetic resonance (NMR), X-ray diffraction (XRD), scanning electron microscopy (SEM), inductively coupled plasma (ICP), and ion chromography (IG). The findings indicate that under current reservoir temperature and pressure conditions, significant asphaltene deposition and calcium carbonate precipitation do not occur during CO₂ flooding. The reservoir’s characteristics-high feldspar content, low carbon mineral content, and low clay mineral content determine that the primary mechanism affecting physical properties under CO₂ flooding in the Chang 4 + 5 tight sandstone reservoir is not, as traditional understand, carbon mineral dissolution or primary clay mineral expansion and migration. Instead, feldspar corrosion and secondary particles migration are the fundamental reasons for the changes in reservoir properties. As permeability increases, micro pore blockage decreases, and the damaging effect of CO₂ flooding on reservoir permeability diminishes. Permeability and micro pore structure are therefore significant factors determining the damage degree of CO₂ flooding inflicts on tight reservoirs. In addition, temperature and pressure have a significant impact on the extent of reservoir damage caused by CO₂ flooding in the study region. At a given reservoir temperature, increasing CO₂ injection pressure can mitigate reservoir damage. It is recommended to avoid conducting CO₂ flooding projects in reservoirs with severe pressure attenuation, low permeability, and narrow pore throats as much as possible to prevent serious damage to the reservoir. At the same time, the production pressure difference should be reasonably controlled during the production process to reduce the risk and degree of calcium carbonate precipitation near oil production wells. Full article

Enhanced oil recovery (EOR) via CO₂ flooding is a promising strategy for improving hydrocarbon recovery and carbon sequestration, yet the influence of pH on solid–liquid interfacial interactions in quartz-dominated reservoirs remains poorly understood. This study employs molecular dynamics (MD) simulations to investigate the pH-dependent adsorption behavior of crude oil components on quartz surfaces and its impact on CO₂ displacement mechanisms. Three quartz surface models with varying ionization degrees (0%, 9%, 18%, corresponding to pH 2–4, 5–7, and 7–9) were constructed to simulate different pH environments. The MD results reveal that aromatic hydrocarbons exhibit significantly stronger adsorption on quartz surfaces at high pH, with their maximum adsorption peak increasing from 398 kg/m³ (pH 2–4) to 778 kg/m³ (pH 7–9), while their alkane adsorption peaks decrease from 764 kg/m³ to 460 kg/m³. This pH-dependent behavior is attributed to enhanced cation–π interactions that are facilitated by Na⁺ ion aggregation on negatively charged quartz surfaces at high pH, which form stable tetrahedral configurations with aromatic molecules and surface oxygen ions. During CO₂ displacement, an adsorption–stripping–displacement mechanism was observed: CO₂ first forms an adsorption layer on the quartz surface, then penetrates the oil phase to induce the detachment of crude oil components, which are subsequently displaced by pressure. Although high pH enhances the Na⁺-mediated weakening of oil-surface interactions, which leads to a 37% higher diffusion coefficient (8.5 × 10⁻⁵ cm²/s vs. 6.2 × 10⁻⁵ cm²/s at low pH), the tighter packing of aromatic molecules at high pH slows down the displacement rate. This study provides molecular-level insights into pH-regulated adsorption and CO₂ displacement processes, highlighting the critical role of the surface charge and cation–π interactions in optimizing CO₂-EOR strategies for quartz-rich reservoirs. Full article

Blue-green algae blooms present persistent environmental challenges in freshwater ecosystems, yet ecological interactions within the bacterial communities of Cylindrospermopsis-bloom reservoirs remain poorly understood. In this study, water samples were collected from February to May 2024 from 11 sampling sites in a Cylindrospermopsis-bloom reservoir in western Guangdong province, China. At each sampling point, a water sample was collected every month. High-throughput sequencing was applied to analyze the interaction between Cylindrospermopsis and other bacteria. As shown in our results, the phyla Actinobacteriota, Proteobacteria, Bacteroidota, Verrucomicrobiota, and Cyanobacteria were revealed as dominant phyla. Bacterial communities exhibited significant seasonal differences between flood and non-flood periods (ANOSIM: R = 0.472, p = 0.001). Cylindrospermopsis (dominance index Y = 0.53) acted as the keystone in the co-occurrence network (Z_i < 2.5, P_i > 0.62) and closely interacted with other bacteria. For better management of the blue-green algae bloom reservoir, the phyla of Actinobacteriota, Dependentiae, Acidobacteriota, Armatimonadota, Gemmatimonadota, and Desulfobacterota were proposed as microbial indicators for the eutrophic process. This study provides a new insight into the interactions of Cyanobacteria with other bacteria and the management of blue-green algae outbreaks in reservoirs. Full article

The impact of water on CO₂ sequestration and enhanced oil recovery processes is significant. In this study, a CO₂–water-film–crude-oil–rock molecular system was established. Then, the influence of water-film thickness on the dissolution and dispersion of CO₂ and crude oil under different temperature and pressure scenarios was examined through molecular dynamics simulations. The results indicate that water films hinder CO₂ diffusion into the oil, reducing its ability to lower oil density. When the thickness of the water film increases from 0 nm to 3 nm, the oil density increases by 86.9%, and the average diffusion coefficient of oil decreases by 72.30%. Increasing the temperature enhances CO₂–oil interactions, promoting CO₂ and water diffusion into oil, thereby reducing oil density. Under conditions of a 2 nm water film and 10 MPa pressure, increasing the temperature from 100 °C to 300 °C results in a decrease of approximately 32.1% in the oil density. Pressure also promotes oil and water-film density reduction, but its effect is less significant compared to temperature. These results elucidate the function of the water film in CO₂-EOR processes and its impact on CO₂ dissolution and diffusion in water-bearing reservoirs. Full article

In bulk liquid or on solid surfaces, nanobubbles (NBs) are gaseous domains at the nanoscale. They stand out due to their extended (meta)stability and great potential for use in practical settings. However, due to the high energy cost of bubble generation, maintenance issues, membrane bio-fouling, and the small actual population of NBs, significant advancements in nanobubble engineering through traditional mechanical generation approaches have been impeded thus far. With the introduction of the electric field approach to NB creation, which is based on electrostrictive NB generation from an incoming population of “electro-fragmented” meso-to micro bubbles (i.e., with bubble size broken down by the applied electric field), when properly engineered with a convective-flow turbulence profile, there have been noticeable improvements in solid-state operation and energy efficiency, even allowing for solar-powered deployment. Here, these innovative methods were applied to a selection of upstream and downstream activities in the oil–water–fuels nexus: advancing core flood tests, oil–water separation, boosting the performance of produced-water treatment, and improving the thermodynamic cycle efficiency and carbon footprint of internal combustion engines. It was found that the application of electric field NBs results in a superior performance in these disparate operations from a variety of perspectives; for instance, ~20 and 7% drops in surface tension for CO₂- and air-NBs, respectively, a ~45% increase in core-flood yield for CO₂-NBs and 55% for oil–water separation efficiency for air-NBs, a rough doubling of magnesium- and calcium-carbonate formation in produced-water treatment via CO₂-NB addition, and air-NBs boosting diesel combustion efficiency by ~16%. This augurs well for NBs being a potent agent for sustainability in the oil and fuels sector (whether up-, mid-, or downstream), not least in terms of energy efficiency and environmental sustainability. Full article

Underground production and injection operations result in mechanical compaction and mineral chemical reactions that alter porosity and permeability. These changes impact the flow and, eventually, the long-term sustainability of reservoirs utilized for CO₂ sequestration and geothermal energy. Even though mechanical and chemical deformations in rocks take place at the pore scale, it is important to investigate their impact at the continuum scale. Rock deformation can be examined using intergranular pressure solution (IPS) models, primarily for uniaxial compaction. Because the reaction rate parameters are estimated using empirical methods and the assumption of constant mineral saturation indices, these models frequently overestimate the rates of compaction and strain by several orders of magnitude. This study presents a new THMC algorithm by combining thermo-mechanical computation with a fractal approach and hydrochemical computations using PHREEQC to evaluate the pressure solution. Thermal stress and strain under axisymmetric conditions are calculated analytically by combining a derived hollow circle mechanical structure with a thermal resistance model. Based on the pore scale, porosity and its impact on the overall excessive stress and strain rate in a domain are estimated by applying the fractal scaling law. Relevant datasets from CO₂ core flooding experiments are used to validate the proposed approach. The comparison is consistent with experimental findings, and the novel analytical method allows for faster inspection compared to numerical simulations. Full article

Anthropogenic CO₂ emissions are a major driver of climate change, highlighting the urgent need for effective mitigation strategies. Carbon Capture, Utilization, and Storage (CCUS) offers a promising approach, particularly through CO₂-enhanced gas recovery (EGR) in shale reservoirs, which enables simultaneous hydrocarbon production and CO₂ sequestration. This study employs a numerical simulation model to compare two injection strategies: CO₂ flooding and huff-and-puff (H&P). The results indicate that, without accounting for key mechanisms such as adsorption and molecular diffusion, CO₂ H&P provides minimal improvement in methane recovery. When adsorption is included, methane recovery increases by 9%, with 14% of the injected CO₂ stored over 40 years. Incorporating diffusion enhances recovery by 19%, although with limited storage potential. In contrast, CO₂ flooding improves methane production by 26% and retains up to 94% of the injected CO₂. Higher storage efficiency is observed in reservoirs with high porosity and low permeability, particularly in nano-scale pore systems. Overall, CO₂ H&P may be a viable EGR option when adsorption and diffusion are considered, while CO₂ flooding demonstrates greater effectiveness for both enhanced gas recovery and long-term CO₂ storage in shale formations. Full article

Why should we prepare for a flood which might never happen? Uncertainty around potential future hazards significantly limits citizens’ disaster preparedness, as it influences decision-making and action-taking greatly. To bridge this knowledge–action gap, we developed a novel, no-regrets framework for sustainable flood preparedness under uncertainty, building on a systematic literature review (PRISMA method) and an integrative review of preparedness actions. The review of 364 articles revealed that while no-regrets principles are widely applied in climate policy and risk management, they are not tailored to personal preparedness. Our resulting framework defines clear no-regrets criteria for individual and household-level preparedness (robustness, flexibility, cost-effectiveness, co-benefits, and ease of implementation) and categorizes 80+ flood preparedness actions according to four levels of uncertainty, from unknown futures to imminent hazards. Notably, we found that long-term preparedness actions remain underutilized, psychological preparedness is largely absent, and existing guidance is biased toward physical risk reduction in high-income contexts. This framework offers a practical tool for practitioners, local authorities, and community groups to promote actionable, context-sensitive flood preparedness worldwide and can be adapted to other hazards in future work. Full article

This work examines how multiphase flow behavior during CO₂ and N₂ displacement in a microfluidic chip under capillary-dominated circumstances is affected by interfacial tension (IFT) and the viscosity ratio. In order to simulate real pore-scale displacement operations, microfluidic tests were performed on a 2D rock chip at flow rates of 1, 10, and 100 μL/min (displacement of water by N₂/supercritical CO₂). Moreover, core flooding experiments were performed on various sandstone samples collected from three different geological basins in Australia. Although CO₂ is notably denser and more viscous than N₂, the findings show that its displacement efficiency is more influenced by the IFT values. Low water recovery in CO₂ is the result of non-uniform displacement that results from a high mobility ratio and low IFT; this traps remaining water in smaller pores via snap-off mechanisms. However, due to the blebbing effect, N₂ injection enhances the dissociation of water clots, resulting in a greater swept area and fewer remaining water clusters. The morphological investigation of the residual water indicates various displacement patterns; CO₂ leaves more retained water in irregular shapes, while N₂ enables more uniform displacement. These results confirm earlier studies and suggest that IFT has a crucial role in fluid displacement proficiency in capillary-dominated flows, particularly at low flow rates. This study emphasizes the crucial role of IFT in improving water recovery through optimizing the CO₂ flooding process. Full article

In recent years, land degradation has become a major challenge for human society, with negative impacts on the natural habitat, the economy, and human well-being. A variety of anthropogenic and natural factors are exacerbating the processes of land degradation in the era of climate change. Land restoration is an important and proactive strategy to combat this negative situation. Among the many approaches, the use of vegetation plays a central role in restoring soil health, preventing erosion, promoting biodiversity, and improving water retention. Therefore, the identification of new plant species that have the properties to contribute to land restoration is a necessity today. The plant proposed in this conceptual review for land restoration is the cup plant (Silphium perfoliatum L.). After a brief presentation of the agronomy, adaptability, and multiple uses of this plant species, its potential to provide important ecosystem services useful for land restoration to combat land degradation is herein emphasized. Recent studies have shown that this plant has great potential for phytoremediation of soils contaminated with heavy metals (Zn, Pb, Cr, Cd, Ni, Hg, and Co), especially in post-mining areas where pollution exceeds ecological limits. Most studies have shown that the accumulation of heavy metals is higher at the lamina stage. There is also some evidence that the cup plant thrives in flood-prone areas and contributes to their restoration. Cup plant cultivation can also reduce greenhouse gasses and increase the organic carbon content of the soil. Another method of land restoration related to the establishment of the cup plant in a given area is the suppression of weeds, particularly the prevention of the invasion of exotic weed species. Further research under different soil–climatic conditions is needed to investigate cup plant cultivation as a promising strategy for land restoration in a time when the climate is constantly changing. Full article

The growing frequency and severity of climate-induced disasters—such as floods, heatwaves, droughts, and wildfires—pose significant threats to sustainable development worldwide. Integrating Climate Change Adaptation (CCA) and Disaster Risk Reduction (DRR) has emerged as a strategy imperative for enhancing societal resilience and protecting developmental gains. This review synthesizes the current knowledge and practice at the intersection of CCA and DRR, drawing on international frameworks, national policies, and local implementation strategies. We assess the role of the Sendai Framework for Disaster Risk Reduction (2015–2030), the Paris Agreement, and the 2030 Agenda for Sustainable Development in promoting policy coherence and multi-level governance. Particular attention is given to the effectiveness of Nature-Based Solutions (NBS), Ecosystem-Based Adaptation (EbA), and community-based approaches that address both climate vulnerabilities and disaster risks while delivering co-benefits for ecosystems and livelihoods. Case studies from regions highly exposed to climate-related hazards, including the Global South and Europe, illustrate how integrated approaches are operationalized and what barriers persist, including institutional silos, limited financing, and data gaps. For example, Bangladesh has achieved over a 70% reduction in flood-related mortality, while Kenya’s drought-resilient agriculture has increased food security by 35% in affected regions. The review highlights best practices in risk-informed planning, participatory decision-making, and knowledge co-production, emphasizing the need for inclusive governance and cross-sector collaboration. By critically examining the synergies and trade-offs between adaptation and risk reduction, this paper offers a pathway to more resilient, equitable, and sustainable development. It concludes with recommendations for enhancing integration at the policy and practice levels, supporting both immediate risk management and long-term transformation in a changing climate. Full article

Foam–CO₂ EOR Flooding is not very successful if unaccompanied by foam stabilizers such as nanoparticle fly ash (NFA). This study was conducted to determine the effect of NFA on foam stability by considering particle characteristics using the Bulk Foam Method as an additional condition. The test resulted in half-life times, which showed that in the absence of NFA, when oil was added, it was 211.5 s, and in salinity conditions, it was 232.5 s. This succeeds in improving half-life times to 226 s (with oil) and 241.5 s (with salinity) by adding NFA-Type F. For further research, conducting tests using reservoir conditions is recommended. Full article

Cadmium (Cd) mobilization in paddy soils during redox fluctuations poses significant risks to rice safety. This study investigated the efficacy of nano-calcium carbonate (NCC), nano-hydroxyapatite (NHAP), and their composite (C+P) in immobilizing Cd under simulated flooding–drainage cycles. Soil treatments (0.5% and 1.0% w/w) were subjected to 40 day anaerobic and 20 day aerobic incubation. The results demonstrated that NCC and C+P elevated the soil pH by 1.35–1.39 and 0.72–1.01 units during the anaerobic and aerobic phases, respectively. These amendments suppressed Fe(II) and Mn(II) release by 41–75%, correlating with reduced Cd bioavailability. While nanomaterials minimally influenced Cd speciation during flooding, aerobic conditions triggered a marked shift: residual Cd fractions increased by 80.8–116.4% under NCC, driven by CdCO₃ precipitation and phosphate complexation. Cd release rates decreased by 53.6–66.8% in NCC and C+P treatments during oxidation. Microbial analysis revealed diminished bacterial diversity but enriched Firmicutes (up to 58.9%), which positively correlated with pH and residual Cd. Redundancy analysis identified pH and Fe/Mn dynamics as key regulators of the microbial community structure. NCC emerged as the most effective amendment. This study highlights the potential of NCC-based strategies for mitigating Cd risks in acidic paddy soils, particularly during post-flooding drainage. Full article