Search Results (237)

(1) Although lotus ponds exhibit ecological benefits in wetland restoration, their efficacy in water purification and eutrophication mitigation remains unclear. (2) This study utilized Jinluo lotus pond as the experimental group and the adjacent river as the control. Five sampling points were established in each area, with water samples collected in June 2022, April 2025, and May 2025. (3) The pH, BOD, COD, TN, and NH₃-N concentrations in Jinluo lotus pond water are higher than those in rivers, while the TP, NO₃-N, Chl-a, and algal cell density in rivers are higher. However, there was no significant difference in the nine parameters (p > 0.05) in June 2022. The pH, DO, algal cell density, and algal biomass of the Jinluo lotus pond were significantly higher (p < 0.05 for DO); the concentrations of BOD, COD, TN, TP, NH₃-N, NO₃-N, PI, and Chl-a in rivers are higher, with significant differences in Chl-a (p < 0.05) in April 2025. The BOD, COD, TP, NO₃-N, and PI of the Jinluo lotus pond were relatively high (p < 0.05 for PI); the pH, TN, NH₃-N, DO, Chl-a, algal cell density, and algal biomass of rivers are higher, with significant differences in Chl-a (p < 0.05) in May 2025. The results showed that there was no significant difference in the four diversity indicators in June 2022, April 2025, and May 2025. There was no significant difference in the algal diversity indices, including species richness (S), Shannon–Wiener diversity index (H), Simpson diversity index (P), and Pielou evenness index (E) between Jinluo lotus pond and rivers. (4) Conclusions and Recommendations: The Jinluo lotus pond and adjacent rivers suffer from severe nutrient overload, especially with BOD, COD, and TN all being classified as Class 5 water. Expanding natural and constructed reed communities is recommended to enhance nutrient removal. However, given the limited purification capacity of lotus ponds, maintaining or increasing their area may not be justified. Full article

Facing the problems in determining the distribution range of karst areas and detecting karst caves under the restrictions of complex building and human exploration environments on the urban surface, taking the karst detection of Tianmeixin village and its southern pond in the north extension section of Guanghua Intercity Railway Line 18 as the application research object, based on the formation mechanism of karst and the existing geophysical detection methods, the electrical resistivity tomography method with a large detection range and the cross-well seismic computed tomography method with a high detection accuracy are used to carry out application research on concealed karst cave detection, which are two geophysical technical detection methods with strong adaptability and anti-interference ability. The results show that the optimized combination of geophysical exploration techniques can effectively overcome the limitations of the environment, draw the main karst development areas, reveal the interface between rock and soil, and accurately characterize the size and shape of karst caves. The electrical resistivity tomography method was used to find a number of potential water conduction channels in the middle zone between Tianmeixin village and the south river. The overall distribution characteristics of karst in Tianmeixin village were summarized, and the key detection areas were drawn. This conclusion was verified by several sets of cross-well seismic computed tomography profiles, which provided a reference for the layout of the subsequent cross-well seismic computed tomography imaging method and greatly reduced the workload of drilling, shortened the construction period, saved on detection costs, and reduced the impact on the production and life of residents. Full article

During a research expedition to the Kanchenjunga Conservation Area (KCA), eastern Nepal, in April–June 2024, local concern was expressed about the rapid development of meltwater ponds upon the terminus of the Kanchenjunga glacier since 2020, especially in terms of the possible formation of a large and potentially dangerous glacial lake. Our resultant study of the issue included informal interviews with local informants, comparison of time series satellite composite images acquired by Sentinel-2 Multispectral Instrument, and modeling of different lake development, outburst flood scenarios, and prospective downstream impacts. Assuming that the future glacial lake will be formed by the merging of present-day supraglacial ponds, filling the low-gradient area beneath the present-day glacier terminal complex, we estimated the potential volume of a Kanchenjunga proglacial lake to be 33 × 10⁶ m³. Potential mass movement-triggered outburst floods would travel downstream distances of almost 120 km even under the small magnitude scenario, and under the worst-case scenario would reach the Indo-Gangetic Plain and cross the border into India, exposing up to 90 buildings and 44 bridges. In response, we suggest that the lower Kanchenjunga glacier region be regularly monitored by both local communities and Kathmandu-based research entities over the next decade. The development of user-friendly early warning systems, hazard mapping and zoning programs, cryospheric hazards awareness building programs, and construction of locally appropriate flood mitigation measures are recommended. Finally, the continued development and refinement of the models presented here could provide governments and remote communities with a set of inexpensive and reliable tools capable of providing the basic information needed for communities to make informed decisions regarding hazard mitigation, adaptive, and/or preventive measures related to changing glaciers. Full article

More than half of the cultivated land belongs to the Irrigation Association. Therefore, there have been no farmland consolidation, irrigation, and drainage projects. The cultivation in the non-irrigation area suffers from poor geographical conditions and a lack of water sources. A practical planning strategy is required for expanding irrigation services. The mountainous area of Nantou County, Taiwan, has 7477 ha of available land and 4656 ha of agricultural land outside the irrigation area. Rain and streams are the main water source. There are 82 ponds, 80% of which belong to the loam soil, and the rainfall from October to February is limited. The water requirement of crops is 1.5–3.1 mm/day. Wild streams, groundwater, and rainwater are the only potential water sources due to elevation and terrain. The potential runoff is estimated to be 0–0.927 cms (m³/s) when using the SCS-CN method. Water supply and demand from October to April are limited, and the rainfall comprises 22% of the total water supply. Large reservoirs and water storage towers are required for flooding and in dry seasons. To address water storage challenges and stabilize the balance between water supply and demand, it is essential to construct additional ponds. Full article

Land use and land cover change (LULCC) is a key driver of carbon storage changes, especially in complex coastal ecosystems such as the Yellow River Delta (YRD), which is jointly influenced by climate change and resource development. The compounded effects of sea-level rise (SLR) and land subsidence (LS) are particularly prominent. This study is the first to integrate the dual impacts of SLR and LS into a unified framework, using three climate scenarios (SSP1–26, SSP2–45, SSP5–85) provided in the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report (AR6), along with LS monitoring data, to comprehensively assess future inundation risks. Building on this, and taking into account land use and ecological protection policies in the YRD, three strategic scenarios—Ecological Protection Scenario (EPS), Natural Development Scenario (NDS), and Economic Growth Scenario (EGS)—are established. The PLUS and InVEST models are used to jointly simulate LULCC and carbon storage changes across these scenarios. Unlike previous studies focusing on single driving factors, this research innovatively develops a dynamic simulation system for LULCC and carbon storage driven by the SLR-LS compound effects, providing scientific guidance for land space development and coastal zone planning in vulnerable coastal areas, while enhancing carbon sink potential. The results of the study show the following: (1) Over the past 30 years, the land use pattern of the YRD has generally extended toward the sea, with land use transitions mainly from grasslands (the largest reduction: 1096.20 km²), wetlands, reservoirs and ponds, and paddy fields to drylands, culture areas, construction lands, salt pans, and tidal flats. (2) Carbon storage in the YRD exhibits significant spatial heterogeneity. Low-carbon storage areas are primarily concentrated in the coastal regions, while high-carbon storage areas are mainly found in grasslands, paddy fields, and woodlands. LULCC, especially the conversion of high carbon storage ecosystems to low carbon storage uses, has resulted in an overall net regional carbon loss of 2.22 × 10⁶ t since 1990. (3) The risk of seawater inundation in the YRD is closely related to LS, particularly under low sea-level scenarios, with LS playing a dominant role in exacerbating this risk. Under the EGS, the region is projected to face severe seawater inundation and carbon storage losses by 2030 and 2060. Full article

Universities and other institutes of higher education could be considered as key actors in the implementation of sustainability pillars, such as the adoption of sustainable practices in wastewater management. However, the adoption of such practices is still an emerging issue. This paper discusses the design and operation of the first combined Oxylag and high rate algal pond (COHRAP) constructed at the university campus in Tunisia for irrigation. Performance was evaluated based on the removal efficiencies of nutrients, chemical oxygen demand (COD), biochemical oxygen demand (BOD), heavy metals, coliforms, and biomass productivity. The potential reuse of sludge and algal biomass is discussed based on the Tunisian national standard regulation for sludge reuse in agriculture (NT 106.20) and the European regulation (EC, 2019/1009) for fertilizer products. Effluent phytotoxicity is tested on the germination and growth on Zea mays L. The results indicate that the COHRAP performance was globally satisfactory; however, biomass productivity (1.4 g m⁻²d⁻¹) was low, indicating the need for adjustments in the operational parameters. Despite the effluent limitations for TSS and Hg, no phytotoxic effect was observed. Regarding the heavy metal content in sludge and algal biomass, the results obtained were in compliance with NT 106.20 and EC, 2019/1009), respectively. The energy consumption of COHRAP is 1.05 kWh/m³ resulting in operational costs of 0.29 euros/m³. This study revealed that COHRAP could be a sustainable option to treat wastewater from university campuses with resource recovery. Such a choice can be improved by the implementation of an algae recovery step. Full article

Nature-based solutions represent a decentralized wastewater treatment proposal, offering diverse mechanisms for effectively removing emerging contaminants, particularly acidic pharmaceuticals. This study evaluated the performance of acidic-drug (diclofenac, fenofibrate, ibuprofen, gemfibrozil, fenoprofen, naproxen, and indomethacin) removal from wastewater using a surface-flow constructed wetland with an organic bed (Eichhornia crassipes (Mart.) Solms, 18 ind/m²), and a horizontal subsurface-flow constructed wetland, divided into three sections. The process was complemented by two stabilization ponds and other horizontal subsurface-flow wetlands using papyrus (Cyperus papyrus L., 8–13 ind/m²) and tezontle as support media. The industrial-scale system (67.8 m²) was fed with wastewater at a rate of 1.33 m³/d with a hydraulic time retention of about 5.8 days. Drugs were quantified by gas chromatography. The results showed that gemfibrozil and indomethacin were completely removed (100%), while diclofenac (73%) and naproxen (94%) showed significant removals. Fenoprofen was not removed. Ibuprofen and fenofibrate showed increased concentrations, resulting in negative removals due to anoxic conditions (ibuprofen) and a slightly neutral pH (fenofibrate). These findings underscore the system’s ability to improve water quality by removing most acidic drugs, suggesting that the hybrid design is particularly effective in treating specific wastewater contaminants. Full article

Beavers play a key role in creating temporary water reservoirs that significantly impact the natural environment and local river hydrology. The primary aim of this study was to assess the potential of increasing the number of beaver dams (Castor spp.), as an alternative method of water retention in the environment. Research conducted on three small lowland streams in central Poland revealed that beaver dams, even in modified riverbeds, enable the formation of shallow floodplains and ponds. Innovative analyses considered the structural materials of the dams and their impact on river hydromorphology and sediment transport. The findings emphasise the importance of beavers in water retention processes, the stabilisation of water levels during low flows and the protection of biodiversity. The study also demonstrated that beaver dams play a critical role in storing surface- and groundwater, mitigating drought impacts, reducing surface runoff, and stabilising river flows. These constructions influence local hydrology by increasing soil moisture, extending water retention times, and creating habitats for numerous species. The collected data highlight the potential of beaver dams as a tool in water resource management in the context of climate change. Further research could provide guidance for the sustainable utilisation of beavers in environmental conservation strategies and landscape planning. Full article

Traditional conservation strategies often prioritize minimizing water use; nevertheless, water can also enhance thermal comfort by incorporating a water-to-air heat exchanger (WAHE) alongside non-direct evaporative and radiant cooling techniques. A WAHE can be installed in features such as ponds, water tanks, or rainwater cisterns. This article assesses the cooling potential of two prototypes of roof ponds and a green roof connected to a WAHE, and the results are compared to a baseline unit featuring a roof that meets California’s energy code standards. Several testing units, measuring 1.35 × 1.35 × 1.35 m, with identical heat characteristics, excluding the roof, were constructed and tested. In the first system, the heat that the green roof could not absorb was transferred to a water reservoir and then dissipated to the outside. The first roof pond prototype features a 0.35 m deep water pond topped with a 0.03 m thick insulating panel and a spray system. The second roof pond variant has an aluminum sheet with a 0.10 m air gap above a 0.25 m deep water pond. The results suggest that combining a WAHE with different roof configurations offers promising benefits while keeping water consumption limited. Notably, when the WAHE is operating, the green roof increase its performance by 47%, the insulated roof pond by 22%, and the roof pond with an aluminum sheet by 13%. Full article

The Integrated Multi-Trophic Aquaculture (IMTA) model is an eco-friendly aquaculture system that enhances water purification through ecological niche utilization. A study employing 16S rRNA sequencing analyzed microbial communities in aquaculture water at initial, middle, and final stages. Results indicated that physicochemical parameters were lower at the final stage. The removal efficiencies of Total Nitrogen (TN) and Total Phosphorus (TP) reached 79.10% and 63.64%, respectively. The Simpson and Shannon indices revealed that microbial diversity was significantly higher in the final stage compared to the initial and middle stages (p < 0.05). Dominant bacterial phyla included Actinobacteria, Proteobacteria, and Bacteroidetes, while dominant genera included Candidatus_Aquiluna, NS3a_marine_group, and NS5_marine_group. Functional prediction results demonstrated that metabolic pathways such as amino acid metabolism, biosynthesis of other amino acids, and energy metabolism were upregulated in the final stage compared to the initial stage. Correlation analysis of environmental factors suggested that TN and TP significantly influenced the microbial community structure. Key microorganisms such as Candidatus_Aquiluna, Marinomonas, and Cobetia played crucial roles in carbon fixation, nitrogen reduction, and phosphorus removal. In summary, the IMTA model effectively purifies water, with microbial communities contributing to the stability of the aquatic environment. Full article

Between the eighth and ninth centuries, the world entered a second period of strong winter monsoons, which precipitated a series of recurrent natural disasters, including reduced summer rainfall and prolonged droughts. The various types of droughts that occurred in southeastern China are documented in historical records, which also include the official-led ritual prayers to the local deities that were conducted during these challenging periods. As evidenced in these historical records, officials implemented a series of measures to provide solace to the populace, including the restoration of shrines and temples and the offering of sacrifices and prayers to the local deities, such as the Wutang God 吳塘神 and the Chutan God 儲潭神. These actions were intended to leverage the influence of the local deities to mobilise labour and financial resources for the implementation of public works, including the reclamation of barren land and the construction of dikes and ponds. These initiatives ultimately proved instrumental in enabling the populace to withstand the adverse effects of disasters. This approach represents a distinctive strategy for coping with drought in ancient China. It may provide insights into how governments and non-governmental organisations can utilise the influence of religious beliefs to unite people in addressing the climate crisis in the present era. Full article

Constructed wetlands play a critical role in mitigating aquaculture wastewater pollution. However, the comprehensive treatment performance of aquatic plants and microorganisms under various water treatment processes remains insufficiently understood. Here, a multi-stage surface flow constructed wetland (SFCW) comprising four different aquatic plant species, along with aeration and biofiltration membrane technologies, was investigated to explore the combined effects of aquatic plants and epiphytic biofilms on wastewater removal efficiency across different vegetation periods and treatment processes. The results demonstrated that the total removal efficiency consistently exceeded 60% in both vegetation periods, effectively intercepting a range of pollutants present in aquaculture wastewater. Changes in the vegetation period influenced the performance of the SFCW, with the system’s ability to treat total nitrogen becoming more stable over time. The removal efficiency of the treatment pond planted with submerged plants was highest in July, while the pond planted with emergent plants showed an increased removal rate in November. The aeration pond played a significant role in enhancing dissolved oxygen levels, thereby improving phosphorus removal in July and nitrogen removal in November. Additionally, the α-diversity of epiphytic bacteria in the aeration and biofiltration ponds was significantly higher compared to other ponds. In terms of bacterial composition, the abundance of Firmicutes was notably higher in July, whereas Nitrospirota and Acidobacteriota exhibited a significant increase in November. Furthermore, the functional genes associated with sulfur metabolism, nitrogen fixation, and oxidative phosphorylation displayed significant temporal variations in the aeration pond, highlighting that both growth period changes and treatment processes influence the expression of functional genes within biofilms. Our findings suggest that the integration of water treatment processes in SFCWs enhances the synergistic effects between aquatic plants and microorganisms, helping to mitigate the adverse impacts of vegetation period changes and ensuring stable and efficient wastewater treatment performance. Full article

Geoenvironmental engineered barriers, such as geotechnical and hydraulic layered structures called liners, are essential for protecting the environment from pollution. Liners are usually compacted clay liners (CCL), geomembranes (GM), geosynthetic clay liners (GCL), or a combination of these liners (composite liners), which require significant attention concerning materials, techniques, and procedures to perform adequately. This work reviews the function of geotechnical and hydraulic barriers as liners and highlights the lack of investigation and problematic aspects of them. In addition, the work provides an overview of the literature around earthworks which are liners’ specific configurations, such as landfills, dams, ponds, wastewater lagoons, and vertical barriers. Furthermore, the main investigations, issues, and perspectives are demonstrated, and are discussed alongside the trending research areas and sustainable new materials. This work highlights different directives in several countries for liner construction standards and testing program specifications, analyzing their economic aspects. The main studies on the subject have been compiled, and a bibliometric analysis was performed. Thus, this paper concludes by pointing out gaps in the research regarding alternative materials and structures within geoenvironmental investigations on liners, and signposts future scientific threads related to sustainable development. Full article

Dry beach parameters are important indicators for measuring the safe operation of tailings ponds. The Unmanned Aerial Vehicle (UAV) is widely used in construction, disaster monitoring, and agriculture. In this paper, a new semi-automatic method is proposed that measures the length and slope of the dry beach in a tailings pond using the point cloud obtained through the 3D reconstruction of UAVs. The programs of dry beach boundary identification, point cloud profile denoising, dry beach length, and slope measurement were established. The proposed method was applied to a case study to monitor the length and slope of a tailings pond dry beach. The results show that the maximum error of the dry beach length measurement is 2.25%, and the error of the slope measurement is 2.67%. The error is within a reasonable range, which can be accepted in practical applications, demonstrating the reliability and accuracy of the proposed method. Compared with traditional methods and image-based dry-beach-monitoring methods, the point cloud model provides comprehensive coverage of the entire dry beach. It enables the measurement of the length and slope of the dry beach at any point while offering an intuitive representation of its surface morphology and topographic features. Full article

Water quality in aquaculture has a direct impact on the growth and development of the aquatic organisms being cultivated. The rapid, accurate and comprehensive control of water quality in aquaculture ponds is crucial for the management of aquaculture water environments. Traditional water quality monitoring methods often use manual sampling, which is not only time-consuming but also reflects only small areas of water bodies. In this study, unmanned aerial vehicles (UAV) equipped with high-spectral cameras were used to take remote sensing images of experimental aquaculture ponds. Concurrently, we manually collected water samples to analyze critical water quality parameters, including total nitrogen (TN), ammonia nitrogen (NH₄⁺-N), total phosphorus (TP), and chemical oxygen demand (COD). Regression models were developed to assess the accuracy of predicting these parameters based on five preprocessing techniques for hyperspectral image data (L2 norm, Savitzky–Golay, first derivative, wavelet transform, and standard normal variate), two spectral feature selection methods were utilized (successive projections algorithm and competitive adaptive reweighted sampling), and three machine learning algorithms (extreme learning machine, support vector regression, and eXtreme gradient boosting). Additionally, a deep learning model incorporating the full spectrum was constructed for comparative analysis. Ultimately, according to the determination coefficient (R²) of the model, the optimal prediction model was selected for each water quality parameter, with R² values of 0.756, 0.603, 0.94, and 0.858, respectively. These optimal models were then utilized to visualize the spatial concentration distribution of each water quality parameter within the aquaculture district, and evaluate the rationality of the model prediction by combining manual detection data. The results show that UAV hyperspectral technology can rapidly reverse the spatial distribution map of water quality of aquaculture ponds, realizing rapid and accurate acquisition for the quality of aquaculture water, and providing an effective method for monitoring aquaculture water environments. Full article