Lake Water Quality Research Articles

Effects of water level changes on the hydrological connectivity and water quality of a lake-type wetland

IntroductionUnderstanding the effects of water level fluctuations on wetland ecosystems is crucial for water resource management and ecological conservation. While there have been some studies on this topic, comprehensive analyses of how water level changes affect the hydrological connectivity and water quality of complex lake-type wetlands remain relatively limited. This work aims to explore the effects of water level changes on the connectivity and water quality of lake-type water bodies in the Huixian Karst Wetland, Guilin.MethodsWater quality data for Mudong Lake from January 2021 to December 2022 were obtained by collecting monthly water samples and conducting laboratory tests for six common water quality parameters. Through a combination of remote sensing image data, drone image data and actual measured data on the Mudong Lake water level, the comprehensive ecological-hydrological connectivity index and comprehensive water quality index were used to evaluate the water level changes in Mudong Lake, water body connectivity, and water quality. The correlations between them were then analysed.ResultsThe results show that as the water level increases, the degree of landscape fragmentation decreases, and the water connectivity index increases by 262%. In addition, as the water level increases, the comprehensive water quality pollution index shows an overall downward trend.DiscussionHowever, the factors affecting lake water quality are complex and changeable. Future research could consider increasing the monitoring frequency during critical periods of rapid hydrological change, such as rainfall-runoff events, to capture more precise and detailed hydrological and water quality data. This study provides an important example of the effects of changes in water level and wetland connectivity on the water quality of a lake ecosystem.

Detecting glacial lake water quality indicators from RGB surveillance images via deep learning

Detecting glacial lake water quality indicators from RGB surveillance images via deep learning

Indigenous Owned Aquatic Monitoring Programs in the Inuvialuit Settlement Region Work: An Adaptive Framework with example Traditional & Local Knowledge Quotes and Coastal Marine Water Quality Data Collected from 2019 to 2022 near Sachs Harbour and Ulukhaktok

Canadian Arctic residents are experiencing longer open water seasons and observing significant change in aquatic species and habitats. Rapid ecosystem change threatens Inuit people’s food security and adds to existing generational trauma caused by ongoing colonialism and industrialization. Indigenous owned environmental monitoring programs prioritize safety, support community empowerment and self-determination to increase the understanding of and resilience to the impacts of this human caused global climate crisis. To this end, in 2019 local expert fishers and hunters from the Inuvialuit Settlement Region worked collaboratively with an independent research scientist to start up community owned aquatic monitoring and observation (AMO) programs in Sachs Harbour and Ulukhaktok in the Inuvialuit Settlement Region. The field teams received training to collect year-round data of lake and coastal water quality data using scientific instruments that measure water temperature, conductivity/salinity, turbidity and dissolved oxygen with depth from the surface down to 150 meters. ROV’s, drones and hydrophones extend observations and Traditional & Local Knowledge (TLK) directs the programs. External clients can hire the teams to augment core funding. AMO teams are finalizing their program and data ownership protocols, which are informed by the Canadian UNDRIP Act and OCAP® principles. Indigenous owned, directed and operated environmental monitoring programs justly deserve funding priority and ongoing public support to help conserve and protect critical areas for future generations.

Evaluation of nutrient loads conveyed to the deep subalpine lakes of Northern Italy through their main tributaries

Nutrient pollution is a critical issue for lakes, leading to cultural eutrophication, which damages the ecosystem and prevents water uses. Proper watershed management practices must be put into action to effectively oppose eutrophication. Because of the complexities and the multiple layers of stakeholders involved in this process, the only factual way to evaluate improvements in watershed nutrient management is to directly estimate nutrient loads at watershed closing sections through available data from environmental monitoring. The Italian deep subalpine lakes (DSLs: Lake Como, Lake Garda, Lake Idro, Lake Iseo, Lake Maggiore) suffered from extensive eutrophication from the 1950s to the early 1980s. Their water quality improved in the 1980s and 1990s after national regulations were introduced to address nutrient pollution. After the turn of the century, increasingly pressing limits on nutrient disposal have been issued, yet steady if not worsening lake water quality conditions have been observed overall. To shed light on the issue, quantifying present and past external loads to these lakes based on direct measurements is essential. In this work, we focused on the main tributaries of the Italian DSLs, employing the observed time series of flowrate and nutrient concentrations to estimate the loading levels of nitrogen and phosphorus and their temporal evolution over a period ranging between 13 and 42 years according to data availability. The LOAD ESTimator (LOADEST) software was adopted to support the load quantification process. Results show that a general decrease in external nutrient loads is still occurring, albeit at a slow pace, the fastest reduction occurring for the Oglio River flowing into Lake Iseo, which has suffered from severe nutrient pollution till recently. Increasing loads have conversely been identified for the Sarca River flowing into Lake Garda. These outcomes highlight the beneficial actions carried out to reduce nutrient pollution, although a decorrelation analysis between external loads and flowrate is suggested for a clearer evaluation of its evolution across the DSLs.

Disruption of boreal lake circulation in response to mid-Holocene warmth; evidence from the varved sediments of Lake Nautajärvi, southern Finland.

Future climate projections are expected to have a substantial impact on boreal lake circulation regimes. Understanding lake sensitivity to warmer climates is therefore critical for mitigating potential ecological and societal impacts. The Holocene Thermal Maximum (HTM; ca 7-5ka BP) provides a valuable analogue to investigate lake responses to warmer climates devoid of major anthropogenic influences. Here, we analyse the micro-X-ray core scanning profiles (μ-XRF) of the annually laminated (varved) sediments from Lake Nautajärvi (NAU-23) in southern Finland to elucidate changes in lake circulation and sedimentation patterns. Principal component analysis (PCA) identifies two key components in the geochemical data associated with the nature of the sediments, i.e. detrital vs organic sedimentation (PC1), and hypolimnetic oxidation (PC2). Our findings reveal that during the HTM, the lake became more sensitive to changes in oxygenation and mixing intensity. These changes were triggered by a warmer climate, which increased organic matter and redox sensitive metal solute concentrations in the water column, strengthening lake stratification and weakening dimictic circulation patterns. Superimposed on HTM weakened circulation are distinct phases of increased oxidation and iron-rich varve formation that do not happen when the background conditions are cooler (i.e. the early and late Holocene). This is driven by temporary strengthening of the mixing regime in response to climatic variability and storminess cycles across southern Scandinavia. These findings demonstrate that whilst warmer conditions weaken boreal lake circulation regimes, they can also make them increasingly vulnerable to short term oscillations in prevalent climatic conditions and weather patterns, which could have significant impacts on lake water quality and aquatic ecosystems. These findings underscore the non-stationary nature of lake sensitivity to short-term climatic variability and emphasize the potential for similar shifts to occur under future warming scenarios.

Effectiveness of agricultural BMPs on phosphorus load reduction for the Canadian Lake Erie basin: A literature review

Lake Erie, the shallowest and warmest of the Great Lakes, has been increasingly threatened by eutrophication and harmful algal blooms affecting economic growth in the region. Excess nutrients, particularly phosphorus, transported with agricultural runoffs have become a major issue of lake water quality. In response to this growing concern over the adverse environmental effects of agriculture, farmers, conservation authorities and governments have worked together to promote and implement best or beneficial management practices (BMPs) in the contributing watersheds that focus on maintaining agricultural activity and farm profitability while protecting the environment. This paper conducted a technical review of BMPs and their effectiveness on phosphorus load reduction from agricultural fields for the Canadian Lake Erie Basin (CLEB). These BMPs include cover crop, conservation tillage, manure incorporation, crop nutrient planning, fragile land retirement, adding organic amendments, reducing soil compaction, controlled tile drain, grassed waterway, vegetative filter strip, riparian buffer, water and sediment control basin, and wetland restoration. Field experiments and modeling studies about BMP effectiveness on phosphorus load reduction from agricultural fields in the CLEB and the Great Lakes region were reviewed and assessed. Findings from other similar geographic regions were also documented for comparison and reference. Because BMPs are site-specific, their phosphorus load reduction effectiveness varied over a wide range in the literature depending upon characteristics of the BMP and local climate, slope, soil type, land use, and land management conditions. Based on the literature review, factors influencing BMP effectiveness were analyzed, and suggestions on research priorities for evaluating BMP effectiveness in the CLEB were provided. This study will benefit decision-makers, watershed conservation authorities, and other stakeholders in estimating phosphorus load reductions from agricultural landscapes and contribute to tracking progress toward achieving Canada’s phosphorus load reduction targets for Lake Erie.

Effects of flood conditions on lake water quality in an agricultural watershed with multiple conservation practices

Effects of flood conditions on lake water quality in an agricultural watershed with multiple conservation practices

Impact of Land Use Change on Lake Pollution Dynamics: A Case Study of Sapanca Lake, Turkey

Modeling non-point source pollution dynamics in inland lake basins is essential for safeguarding water quality, maintaining ecosystem integrity, protecting public health, and advancing long-term environmental sustainability. This study explores non-point pollution dynamics in the Sapanca Lake basin, Turkey, in association with the basin’s land use, land cover, hydrology, pollutant sources, and water quality parameters. The required data were gathered via a three-year monitoring program, which was carried out at 12 sampling stations around the lake, as well as using the collecting field measurements and GIS databases. Stepwise multiple regression analysis was employed to determine the best relation between non-point pollutants and land features. The results showed that urbanization and population density have significant correlations with the total nitrogen (TN) and total phosphorus (TP) in the study areas. Rivers crossing pristine areas, such as forests and uncultivated lands, demonstrated better water quality, thereby positively contributing to the lake ecosystem conservation. The highest nutrient loads were observed in streams that flow through highly urbanized sub-basins, followed by predominantly agricultural areas. This is likely due to runoff from urban environments, leaching from cultivated land, and contributions from livestock and tourism facilities. Conversely, densely forested regions exhibited the lowest levels of nutrient loads, highlighting their capacity for nutrient retention. The peak levels of non-point source pollution (TN = 5.22 mg/L and TP = 0.53 mg/L) were recorded in catchments with the highest degree of urbanization, whereas the lowest values (TN = 0.28 mg/L and TP = 0.04 mg/L) were found in the least urbanized areas. These findings emphasize that nutrients primarily impact water quality because of increasing urban and agricultural activities, while forested land plays a vital role in preserving lake water quality. To ensure sustainable water quality in lake basins, it is essential to strike a careful balance between protective measures and utilization policies, prioritizing conservation efforts.

Sluice Gate Operation and Managed Water Levels Improve Predicted Estuarine Lake Water Quality

Saemangeum Lake, an artificial estuarine lake, suffers from a pollutant load from an upstream watershed that is insufficiently mitigated by current load reduction measures. However, no studies have reported simulated flow direction and velocity for a lake. This study aimed to present an alternative solution based on managing water levels and sluice gate operation. Data were collected on water quality, sluice gate operation, water levels, tidal currents, and flow velocities. Next, the inflow and outflow volumes through the sluice gates were calculated. The Delft3D model was applied to predict water quality in a number of simulated scenarios. Finally, streamline and vorticity were calculated to evaluate hydraulic phenomena, while the ecology-based seawater quality index was employed to evaluate water quality. Analysis of flow characteristics revealed a large-scale clockwise vortex formed in the area where the Mangyeong River meets one of the sluice gates. It revealed a two-layer circulation with different flows in the surface and bottom layers. Evaluation of predicted water quality showed that one-way circulation, alternated in 15-day cycles, significantly improved major water quality items at most stations. Collectively, these findings demonstrate the effect that gate operation and managed water levels can have on the water quality of estuarine lakes. Doi: 10.28991/CEJ-2025-011-01-015 Full Text: PDF

Comparison of Degradation Differences in Typical Urban Wastewater Dissolved Organic Matter

Dissolved organic matter (DOM) is a class of organic mixtures commonly found in natural water bodies with complex structures and diverse sources, which are closely related to the structure and function of the water body environment. Given the declining quality and quantity of lake waters in China, studying the dynamic degradation/change processes of DOM in lakes is essential to understand and manage the ecological health of these water bodies. In this experiment, by conducting photocatalytic experiments of DOM, we analyzed and compared the changes of absorbance and DOC concentration of different kinds of urban wastewater water samples with time, and the results showed that the degradation efficiencies of DOC were in the order of domestic wastewater>farming wastewater>industrial wastewater from the largest to the smallest, and the degradation efficiencies of the light-absorbable substances at the wavelength of 254 nm were farming wastewater>industrial wastewater>domestic wastewater. This study not only explored the photo-degradation process of DOM in urban wastewater, but also provided a scientific basis for wastewater treatment and management, with a view to optimizing the wastewater treatment process, improving the level of water quality management and reducing the impact of harmful pollutants on the environment.

Evaluation of atmospheric correction algorithms for salt lake water assessment: Accuracy, band-specific effects, and sensor consistency

Atmospheric correction plays an important role in satellite monitoring of lake water quality. However, different atmospheric correction algorithms yield significantly different accuracy for inland lake waters beset by shallowness and turbidity. Finding a suitable algorithm for a specific lake is critical for quantitative satellite water-environmental monitoring. This study used Landsat 8 and Sentinel 2 L1 level data of Ebinur Lake in arid northwest China on May 19, 2021. Atmospheric corrections were performed using FLAASH, QUAC, 6S, Acolite-DSF and Acolite-EXP algorithms. The Sentinel 2 reflectance product verified the consistency of the algorithms. Quasi-simultaneously measured hyperspectral data determined the algorithm applicable to Ebinur Lake waters. The results indicate that the Acolite-DSF algorithm has good consistency and high accuracy in the atmospheric correction of Landsat 8 and Sentinel 2 images. Extracting the atmospheric correction of Landsat 8 images found relative error at 0.3 in the Blue, Green, and Red bands and 0.5 in the NIR band. For comparison, the relative errors of Sentinel 2 in all bands are 0.3. Therefore, these four bands of Landsat 8 and Sentinel 2 data are recommended for temporal monitoring of water-environmental parameters in Ebinur Lake. Besides identifying the suitable atmospheric correction algorithm for Ebinur Lake, this study analyzed the atmospheric correction errors of common wavebands for remote sensing monitoring of water bodies, especially applicable for inland salt lakes of arid regions.

Spatiotemporal Analysis and Risk Prediction of Water Quality Using Copula Bayesian Networks: A Case in Qilu Lake, China

Lake water pollution under anthropogenic influences exhibits characteristics of high uncertainty, rapid evolution, and complex control challenges, presenting substantial threats to ecological systems and human health. Quantitative risk prediction provides crucial support for water quality deterioration prevention and management. This study employed the Copula Bayesian Network model to conduct a comprehensive risk assessment of water quality in Qilu Lake, China (2010–2020), incorporating inter-indicator correlations and multiple uncertainty sources. Analysis revealed generally “worse” water quality conditions (5.10 ± 1.35) according to established index classifications, with predicted probabilities of reaching “deteriorated” status ranging from 11.80% to 47.90%. Significant spatial and temporal variations in water quality and pollution risk were observed, primarily attributed to intensive agricultural non-point source loading and water resource deficiency. The study established early warning thresholds through key indicator concentration predictions, particularly for the southern region where “deteriorated” risk levels corresponded to specific ranges: TN (3.42–8.43 mg/L), TP (0.07–1.29 mg/L), and CODCr (27.75–67.19 mg/L). This methodology effectively characterizes lake water quality evolution while enabling risk prediction through key indicator monitoring. The findings provide substantial support for water pollution control strategies, risk management protocols, and regulatory decision-making for lake ecosystem administrators.

Performance Analysis of a Solar-Powered Pulverizing Aerator

The global energy crisis is associated with the need to search for low-energy technical solutions. Such solutions are also introduced in the field of protection and restoration of surface waters. The aim of this work was to determine the efficiency of the AS15000 pulverizing aerator powered by solar energy. The innovative solutions of the aerator presented in this manuscript are subject to a patent application. A simulation was carried out taking into account the efficiency of the aerator pump and the sunlight conditions for the indicated location. The analysis was carried out for the location of an artificial reservoir—Zalew Średzki in Środa Wielkopolska (Poland). The simulation showed that during 6515 h of aerator operation, the pulverizing system pumped as much as 97,725 m3 of lake water. The amount of pure oxygen introduced into the water during the operation of the device can be as much as 1074.98 kg. The minimum daily value of sunlight enabling continuous operation of the device (24 h a day) with maximum efficiency is 1.43 kW/m2. Deoxygenated water in the pulverizing aeration process is taken from the bottom zone, transported to the surface and sprayed in the atmospheric air. Oxygenated water is intercepted and discharged to the bottom zone. Developing artificial aeration methods for lakes in combination with renewable energy sources is very important for improving water quality. The use of solar power allows the device to be used when it is far from the power infrastructure. This also allows the installation of aerators in the middle of the lake. In accordance with the Water Framework Directive, we should strive to improve the water quality of many European lakes as quickly as possible.

Improved Detection of Great Lakes Water Quality Anomalies Using Remote Sensing

Due to their immense economic and recreational value, the monitoring of Great Lakes water quality is of utmost importance to the region. Historically, this has taken place through a combination of ship-based sampling, buoy measurements, and physical models. However, these approaches have spatial and temporal deficiencies which can be improved upon through satellite remote sensing. This study details a new approach for using long time series of satellite remote sensing data to identify historical and near real-time anomalies across a range of data products. Anomalies are traditionally detected as deviations from historical climatologies, typically assuming that there are no long-term trends in the historical data. However, if present, such trends could result in misclassifying ordinary events as anomalous or missing actual anomalies. The new anomaly detection method explicitly accounts for long-term trends and seasonal variability by first decomposing a 10-plus year data record of satellite remote sensing-derived Great Lakes water quality parameters into seasonal, trend, and remainder components. Anomalies were identified as differences between the observed water quality parameter from the model-derived expected value. Normalizing the anomalies to the mean and standard deviation of the full model remainders, the relative anomaly product can be used to compare deviations across parameters and regions. This approach can also be used to forecast the model into the future, allowing for the identification of anomalies in near real time. Multiple case studies are detailed, including examples of a harmful algal bloom in Lake Erie, a sediment plume in Saginaw Bay (Lake Huron), and a phytoplankton bloom in Lake Superior. This new approach would be best suited for use in a water quality dashboard, allowing users (e.g., water quality managers, the research community, and the public) to observe historical and near real-time anomalies.

Comprehensive assessment of surface water quality and pollution sources in Al-Muzaynah dam lake, Syria: insights from multivariate statistical analysis

Comprehensive assessment of surface water quality and pollution sources in Al-Muzaynah dam lake, Syria: insights from multivariate statistical analysis

Management implications following the reconstruction of the small and shallow Lake Mustijärv (Estonia)

Lake Mustijärv was reconstructed by sediment removal following an almost complete siltation. Here we evaluate challenges and opportunities for the management of the lake. We focused on the stream discharging to the lake (i.e., external loading), sediment retention in accumulation basins (i.e., internal processes) as well as the ecosystem-level response to stressors based on biological variables (phyto- and zooplankton, macrophytes, fishes and zoobenthos). Urban and agricultural inputs elevated ammonium and total phosphorus concentrations in the lake, challenging lake reconstruction efforts. Sediment transport highly increased the risk of faster filling of the lake, associated with upstream streambed excavation. Sediments trapped at the accumulation basins release nutrients that enhance eutrophication. We, however, observed a rapid recovery in fish, macrophytes, and zoobenthos, despite the significant disturbances. Lake Mustijärv is in eutrophic condition, reflected by phytoplankton (Pseudanabaena, Closteriopsis dominance) and zooplankton (Keratella, Polyarthra dominance) composition. To improve lake water quality will require controlling external nutrient inputs, underlining the importance of better coordinated activities between the local (lake restoration) and regional (catchment use) scales.

A Framework for Understanding the Impacts of Thaw‐Driven Disturbance Regimes on Northern Lakes

ABSTRACTThe impacts of permafrost thaw do not manifest uniformly across the Arctic, and this presents challenges for predicting how permafrost‐affected lakes will respond to climate change. Here, we leveraged long‐term field data collection and studies of a particular permafrost lake type (predisposed to thaw slump disturbance) in the Tuktoyaktuk Coastlands region to develop a conceptual model that can shed light on, and facilitate further testing of, lake ecosystem impacts associated with polycyclic shoreline retrogressive thaw slumps. To inform the development of the model, we compared regional changes in slump activity and lake water quality variables known to be impacted by slumping between 2005 and 2017, and showed that the timeline to recovery in lake dissolved organic carbon (DOC) following slump stabilization was longer than the time between cycles of slump growth, stabilization, and re‐initiation in most lakes. We also analyzed geochemical changes in sediment cores that incorporated the last several hundred years of history in 18 lakes that spanned a gradient in thaw slump disturbance, as well as a core dating back to ca. 1365 CE in a lake with an ancient slump. Results indicate that sediment geochemical changes were most pronounced at the initial onset of slumping, with only muted changes in sediment characteristics upon slump growth or re‐initiation. Our conceptual model can guide future investigations into the extent to which lakes with polycyclic slumps are predisposed to, or buffered against, significant limnological changes under anthropogenic climate warming. While our model is specific to lake systems in ice‐cored morainal terrain impacted by retrogressive thaw slumping, similar approaches would be highly useful for understanding ecosystem response under a range of permafrost disturbance categories.

The farmgate phosphorus balance as a measure to achieve river and lake water quality targets

This short communication proposes a pathway for achieving river and lake water quality phosphorus (P) targets using the agricultural farmgate P balance (FPB). The context is the internationally important Lough Neagh and general river network in Northern Ireland (NI). A meta-analysis shows a direct and strong linear relationship between the FPB and, with a one-year lag, the mean soluble reactive phosphorus (SRP) concentration for ninety-three river sites over eighteen years (R2 = 0.73, p < 0.01) during quiescent conditions. The model suggests that a reduction of the national FPB to 5.5 kg ha−1 yr−1 will improve up to 100% of river SRP mean annual concentrations to at least the moderate/good boundary target for SRP status, and 25% to the good/high status. In Lough Neagh, the moderate/good boundary is an in-lake mean annual total P (TP) concentration target of 0.044 mg L−1. The annual TP load normalised to a flow weighted mean concentration (FWMC) required to achieve this target in the eight major Lough Neagh rivers is 0.109 mg L−1. Applying a five-year time lag to the TP FWMC data when compared to the FPB also indicates 5.5 kg ha−1 yr−1 as a way to reach this in-lake target (R2 = 0.72, p < 0.01). Allowing for non-FPB sources being part of P mitigation strategies would either speed up the process of P reductions in rivers and to lakes, or relieve the burden to the agricultural sector if a FPB was increased proportionally to an optimum target.

Secchi Depth Retrieval in Oligotrophic to Eutrophic Chilean Lakes Using Open Access Satellite-Derived Products

The application of the Multispectral Instrument (MSI) aboard Sentinel-2A/B constellation for assessing water quality in Chilean lakes represents an emerging area of research, particularly for the environmental monitoring of optically complex water bodies. Similarly, atmospheric correction processors applied to aquatic environments, such as the Case 2 Networks (C2RCC-Nets), are notably underrepresented. This study evaluates the capability of C2RCC-Nets using different neural networks—Case-2 Regional/Coast Color (C2RCC), C2X-Extreme (C2X), and C2X-Complex (C2XC)—to estimate Secchi depth in Lake Lanalhue (eutrophic), Lake Villarrica (oligo-mesotrophic), and Lake Panguipulli (oligotrophic). The evaluation used different statistical methods such as Spearman’s correlation and normalized error metrics (nRMSE, nMAE, and nbias) to assess the agreement between satellite-derived data and in situ measurements. C2XC demonstrated the best fit for Lake Lanalhue, with an nRMSE = 33.13%, nMAE = 23.51%, and nbias = 8.57%, in relation to the median ground truth values. In Lake Villarrica, the C2XC neural network displayed a moderate correlation (rs = 0.618) and error metrics, with an nRMSE of 24.67% and nMAE of 20.67%, with an nbias of 4.21%. In the oligotrophic Lake Panguipulli, no relationship was observed between estimated and measured values, which could be related to the fact that the selected neural networks were developed for very case 2 waters. These findings highlight the need for methodological advancements in processing satellite-derived water quality products for Chile’s optical water types, particularly for very clear waters. Nonetheless, this study underscores the need for model-specific calibration of C2RCC-Nets, as lakes with different optical water types and trophic states may require tailored training ranges for inherent optical properties.

Impact of Anthropogenic Activities on Mavala Lake's Water Quality In Adilabad, Telangana, India

Impact of Anthropogenic Activities on Mavala Lake's Water Quality In Adilabad, Telangana, India