Largest Artificial Lake Research Articles

Stoichiometric and Accumulation Characteristics of Nitrogen and Phosphorus in Artificial and Natural Herbaceous Plants along Lakeshore Buffer Zone

Lakeshore buffer zones serve as transitional areas between terrestrial and aquatic ecosystems, playing a crucial role in intercepting non-point source pollutants, purifying river and lake water, and maintaining ecological system dynamics. This study focuses on the vegetation of the lakeshore buffer zone in Songhua Lake, the largest artificial lake in Northeast China. The nitrogen (N) and phosphorus (P) pollutant contents and accumulation characteristics of herbaceous plants were investigated and analyzed in different regions and with different species. The study results indicate that there were no significant differences in N and P content, N: P ratio, and average accumulation among vegetation in the near-water, middle, and far lakeshores of the buffer area. The herbaceous plants with the highest N and P content and N: P ratios were Artemisia sieversiana, Sium suave, and Artemisia sieversiana, respectively. Purus frumentum planted in the middle lakeshore accumulated the highest amounts of N and P, reaching 87.97 g plant−1 and 3.86 g plant−1, respectively. The aboveground parts of plants showed significantly higher accumulation of N and P compared to the underground parts. The average enrichment coefficient for aboveground parts and underground parts for N were 4.83 and 4.35, respectively, all exceeding 1. However, their capability to enrich P was relatively weak, with only the aboveground parts of F − 3 showing some enrichment ability. Among herbaceous plants, Artemisia sieversiana and Sium suave exhibited the strongest capability for transporting N and P from underground to aboveground. Overall, harvesting aboveground biomass for the ecological removal of N and P in the study area appears feasible. Biomass is a critical factor influencing the nutrient interception capacity of vegetation, with Purus frumentum identified as an optimal restoration plant for sustainable management practices, and Artemisia sieversiana and Sium suave have the potential for rapid remediation.

The Spatiotemporal Eutrophication Status and Trends in the Paldang Reservoir, Republic of Korea

The Paldang Reservoir (PDR), the largest artificial lake in the Republic of Korea, has recently experienced increased chemical oxygen demand (COD), eutrophication, and algal blooms due to climate change. This study aimed to analyze the hydrological characteristics and water quality of the PDR and assess its spatial and seasonal eutrophication status changes using the Korean-type trophic quality index (TSIKO) and the seasonal Mann–Kendall Test (SMK). The PDR’s water was graded “good” in terms of biochemical oxygen demand (BOD) and “fair” for COD, total phosphorous (TP), and chlorophyll-a (Chl-a), according to Korean water quality standards. COD and Chl-a had a significant positive monotonic relationship. According to the TSIKO calculations, the trophic state of the PDR was mesotrophic, but eutrophic during the summer season. TSIKO (Chl-a) in summer tended to increase with a slope value of 0.22 mg/m3/year. The main causes of eutrophication in the PDR were proposed to be TP and phytoplankton overgrowth. Therefore, lake and reservoir functions need to be assessed, and solutions that can effectively protect them from excessive eutrophication to ensure sustainable clean water use and protect freshwater ecosystems need to be found.

A new framework for water quality forecasting coupling causal inference, time-frequency analysis and uncertainty quantification

Accurate forecasting of water quality variables in river systems is crucial for relevant administrators to identify potential water quality degradation issues and take countermeasures promptly. However, pure data-driven forecasting models are often insufficient to deal with the highly varying periodicity of water quality in today's more complex environment. This study presents a new holistic framework for time-series forecasting of water quality parameters by combining advanced deep learning algorithms (i.e., Long Short-Term Memory (LSTM) and Informer) with causal inference, time-frequency analysis, and uncertainty quantification. The framework was demonstrated for total nitrogen (TN) forecasting in the largest artificial lakes in Asia (i.e., the Danjiangkou Reservoir, China) with six-year monitoring data from January 2017 to June 2022. The results showed that the pre-processing techniques based on causal inference and wavelet decomposition can significantly improve the performance of deep learning algorithms. Compared to the individual LSTM and Informer models, wavelet-coupled approaches diminished well the apparent forecasting errors of TN concentrations, with 24.39%, 32.68%, and 41.26% reduction at most in the average, standard deviation, and maximum values of the errors, respectively. In addition, a post-processing algorithm based on the Copula function and Bayesian theory was designed to quantify the uncertainty of predictions. With the help of this algorithm, each deterministic prediction of our model can correspond to a range of possible outputs. The 95% forecast confidence interval covered almost all the observations, which proves a measure of the reliability and robustness of the predictions. This study provides rich scientific references for applying advanced data-driven methods in time-series forecasting tasks and a practical methodological framework for water resources management and similar projects.

An overview on hydro-biology and management of Kaptai Lake Fisheries, Bangladesh

Kaptai Lake is the largest artificial Lake in Bangladesh. This Lake provides most of the fish stock for the people of the Hill tract. Over the years, due to various anthropogenic and environmental reasons population of Indian Major Carp (IMCs) has declined, and some native species are on the way to extinction in this Lake. Considerable research has been conducted on different aspects of lake fishery with hydrology, culture technology, fish diversity, management, threats, and mitigations, but no such consolidated report on the overall overview is not available on this Lake. This review paper has been prepared to combine all the available information along the information gap, further study of which will be helpful to enhance the Indian major carp catch and sustainable management of fish stock.

Genomic Analysis and Taxonomic Characterization of Seven Bacteriophage Genomes Metagenomic-Assembled from the Dishui Lake.

Viruses in aquatic ecosystems exhibit remarkable abundance and diversity. However, scattered studies have been conducted to mine uncultured viruses and identify them taxonomically in lake water. Here, whole genomes (29-173 kbp) of seven uncultured dsDNA bacteriophages were discovered in Dishui Lake, the largest artificial lake in Shanghai. We analyzed their genomic signatures and found a series of viral auxiliary metabolic genes closely associated with protein synthesis and host metabolism. Dishui Lake phages shared more genes with uncultivated environmental viruses than with reference viruses based on the gene-sharing network classification. Phylogeny of proteomes and comparative genomics delineated three new genera within two known viral families of Kyanoviridae and Autographiviridae, and four new families in Caudoviricetes for these seven novel phages. Their potential hosts appeared to be from the dominant bacterial phyla in Dishui Lake. Altogether, our study provides initial insights into the composition and diversity of bacteriophage communities in Dishui Lake, contributing valuable knowledge to the ongoing research on the roles played by viruses in freshwater ecosystems.

Distribution Characteristics of Carbon, Nitrogen, and Phosphorus and Pollution Load Estimation of Sediments in Danjiangkou Reservoir, China

Danjiangkou Reservoir is a world-famous large artificial freshwater lake that offers water resources for the middle route of the South-to-North Water Diversion Project in China. In this study, the distribution of carbon, nitrogen, and phosphorus in reservoir sediments and their pollution assessments were elucidated at different water periods. The average TN (total nitrogen), TP (total phosphorus), and TOM (total organic matter) contents were 794.8 mg/kg, 807.2 mg/kg, and 8.7% in the nonflood season, respectively. When the time comes to flood season, with the large amount of nitrogen pollution inputted from peripheral nonpoint sources and phosphorus released by the accelerated exchange of water bodies, the average TN concentration increased to 1061.2 mg/kg. In addition, the average TP and TOM contents were reduced to 559.5 mg/kg and 6.3%. Nutrient pollution fluctuated between the safe and lowest level. Reservoir eutrophication risk was low. There was a certain nitrogen enrichment in the Danjiangkou Reservoir, and the flood season was the main period of nitrogen pollution input. Water exchange during flood season might accelerate organic matter degradation. Near the dam, sediment organic matter content increased significantly, reaching severe pollution levels. The results of the simulated sediment nutrient release test showed that the nitrogen and phosphorus in the reservoir would release slowly. Moreover, their annual release flux was calculated as 470.4 t and 87.9 t, respectively. It illustrated that the internal pollution of Danjiangkou Reservoir was light, and the release amount was small, so it was not the main pollution source of the reservoir at present.

Restoration of Qaraoun Lake aquatic life based on wetland treatment concept

Qaraoun Lake, the largest artificial lake in Lebanon, suffered severe environmental issues due to discharging untreated domestic and industrial wastewater into it, throwing garbage, which transformed this lake into waste storage instead of using the water for agricultural purposes and making the surrounding places attractive for tourists as was before. Moreover, the violations on Litany River, Lebanon's main artery, also affected Qaraoun Lake. Therefore, this main reservoir suffers from annual blooms of potentially toxic cyanobacteria. Recently, tons of fish are washed up at the surface of the water, agricultural areas are irrigated with polluted water and the Qaraoun Lake is no longer an attractive touristic place. Besides, the climate change represented in lower precipitation and higher evaporation rates in the past few years in addition to the increase in the water demand due to the growth in the local population and the refugees from nearby countries have affected the vulnerability of the water sector in Lebanon. All these issues have resulted in the deterioration of the water quality, generating environmental issues, and seriously affecting the ecosystem. The purpose of this research is to investigate possible remediation strategies, which could help in the restoration of the Qaraoun reservoir. For this purpose, the Litani River water quality and hydrological data are collected from the Litani River Authority (LRA). Moreover, a hydrodynamic water quality model has been developed using Mike21 in order to restore the lake's aquatic life by eliminating the Litani River nutrients through constructed wetland concept, which reasonably simulated the water quality parameters of Qaraoun Lake. Consequently, the wetland could remarkably reduce the Litani River pollutants by 85%, 43.7%, 57%, and 56% for BOD, Phosphorous, Nitrate, and Ammonia, respectively. The resulted treated water, after passing the wetland, successfully improved the lake water quality and may lead to re-originate its ecosystem.

Diatomological Profile at Discrete Depths of Powai Lake, Mumbai for Medico-Legal Purposes

Diatoms are photosynthetic microorganisms that play important role in forensic diatomology in the diagnosis of drowning deaths. In the present study, the Diatomological profile of Powai lake was prepared for medico-legal purposes using the Shannon-Wiener index. Powai lake (19.1266° N, 72.9062° E) is a large artificial lake situated in a northern suburb of Mumbai. Diatoms sampling was conducted in February 2017 from this lake. This study aimed to identify the various genera of diatoms and to determine the relative abundance, generic counting, and diversity index of diatoms for the medico-legal purposes. Littoral benthic diatoms of five locations were sampled from this lake. Diatoms slides were prepared by scraping the rock surface with an area of 3x3 cm, diluting in 50 ml distilled water, and identification under the microscope with 1000 magnification. Identification of 17 genera of diatoms was done using the web-based visual guide ‘Diatoms of the United States’. Diatoms belong to both the orders Centrales and Pennales. The pH of the lake water was found to be 7.64 i.e. slightly alkaline and the temperature was 27°C. Water quality parameters showed a fairly good value for the growth of diatoms. Samples were dominated by class Bacillariophyceae, which included 9 genera followed by Coscinodiscophyceae, with 6 genera, and Fragilariophyceae, with 2 genera. Generic counts of diatoms were obtained by using the ‘Neubauer’ Counting chamber. The Shannon-Wiener diversity index (H') ranges from 1.042 in Epipelic to 0.454 in Emerged Epiphytic diatoms. The purpose of this study was to prepare a diatomological profile of diatoms at discrete depths for medico-legal purposes.

Accumulation by dispossession: The timber ‘salvage’ project on Ghana's Volta Lake

In this paper, we analyse how processes of accumulation by dispossession take place and are exacerbated on Ghana's Volta Lake, the largest artificial lake in the world. Drawing on the case of an underwater timber ‘salvage’ project on the lake, we argue that contrary to dominant discourses in policy circles that the project would boost the local economy, enhance safer lake transport, and help to mitigate climate change, the project led to the commodification of the lake thereby negatively affecting fishers’ livelihoods. Following David Harvey, we argue that the underwater timber ‘salvage’ project on the Volta Lake is just another vehicle of ‘accumulation by dispossession’. The study shows that the state and extractive company accumulate profit at the expense of fishers whose livelihoods have been curtailed following restrictions in access to the lake and landowners who are challenging ownership of the timber being extracted from the lake. Global connections are made, and the inequalities and injustice enacted through the execution of the project are amplified.

Water microecology is affected by seasons but not sediments: A spatiotemporal dynamics survey of bacterial community composition in Lake Changshou—The largest artificial lake in southwest China

This study aimed to evaluate the correlation between microecology of sediments and water as well as their spatial-temporal variations in Changshou Lake. The results demonstrated that microecology in the lake exhibits spatiotemporal heterogeneity, and microbial diversity of sediments was significantly higher than that of water body. Further, it was found that there was statistically insignificant positive correlation between microecology of sediments and that of water body. PCoA and community structure analysis revealed that the predominant phyla which exhibited significant spatial differences in sediments were Proteobacteria, Actinobacteria and Planctomycetes. While, the distribution of dominant bacteria Actinobacteria and Verrucomicrobia in water body showed significant seasonal differences. Microbial networks analysis indicated that there was a cooperative symbiotic relationship between lake microbial communities. Notably, the same bacterial genus had no significant positive correlation in sediment and water, which suggested that bacteria transport between sediment-water interface does not influence the microecological functions of lake water.

Diversity and abundance of plankton in different habitat zonation of Papan River, Lake Kenyir, Malaysia

Abstract. Ramlee A, Suhaimi H, Rasdi NW. 2021. Diversity and abundance of plankton in different habitat zonation of Papan River, Lake Kenyir, Malaysia. Biodiversitas 23: 212-221. Lake Kenyir is the largest artificial lake in Malaysia, yet there is limited information regarding the lake’s ecology. This study aimed to determine the diversity and abundance of phytoplankton and zooplankton in various habitat ecosystems along the Papan River, Lake Kenyir. Three distinct sampling points were chosen based on the diverse habitat conditions, namely sampling point A (high water current area), sampling point B (shallow and muddy area) and sampling point C (minimum water current area). Samples were collected horizontally using a 30µm plankton net with two distinct towing methods: boat and hand towing to specific areas. The result showed that all sampling points had low chlorophyll-a concentrations ranging between 10 and 20 g/ml, indicating that no algae bloom had occurred. Bacillariophyta were found to have the highest distribution of phytoplankton division in all of the stations (50.96%). The other division discovered was Chlorophyta (29.62%), followed by Charophyta (19.43%). Additionally, 140 individual zooplankton species were discovered across all sampling locations. The phylum Rotifera is the most dominant in terms of species distribution (60.00 %), followed by Arthropoda (31.43%), Ciliophora (7.14%), and Rhizopoda (0.71%). The Shannon diversity index, evenness, and species richness measurements at sampling point A, B, and C revealed a range of index values due to variation in plankton species due to interaction and habitat conditions. The variation in planktonic abundance in the Papan River was attributed to their habitat preferences due to the freshwater lake's ecosystem's different zones and conditions.

Investigation of the Occurrence of Cyanotoxins in Lake Karaoun (Lebanon) by Mass Spectrometry, Bioassays and Molecular Methods.

Lake Karaoun is the largest artificial lake in Lebanon and serves multiple purposes. Recently, intensive cyanobacterial blooms have been reported in the lake, raising safety and aesthetic concerns related to the presence of cyanotoxins and cyanobacterial taste and odor (T&O) compounds, respectively. Here, we communicate for the first time results from a recent investigation by LC-MS/MS covering multiple cyanotoxins (microcystins (MCs), anatoxin-a, cylindrospermopsin, nodularin) in water and fish collected between 2019 and 2020. Eleven MCs were identified reaching concentrations of 211 and 199 μg/L for MC-LR and MC-YR, respectively. Cylindrospermopsin, anatoxin-a and nodularin were not detected. The determination of the total MCs was also carried out by ELISA and Protein Phosphatase Inhibition Assay yielding comparable results. Molecular detection of cyanobacteria (16S rRNA) and biosynthetic genes of toxins were carried out by qPCR. Untargeted screening analysis by GC-MS showed the presence of T&O compounds, such as β-cyclocitral, β-ionone, nonanal and dimethylsulfides that contribute to unpleasant odors in water. The determination of volatile organic compounds (VOCs) showed the presence of anthropogenic pollutants, mostly dichloromethane and toluene. The findings are important to develop future monitoring schemes in order to assess the risks from cyanobacterial blooms with regard to the lake’s ecosystem and its uses.

Evaluation of Some Biomarkers in Carp (Cyprinus carpio Linnaeus, 1758) Depending on Water and Sediment Pollution of Atatürk Dam Lake

In this study, some environmental pollution parameters of the Atatürk Dam Lake which is Turkey's largest artificial lake and meeting the irrigation and energy needs of Adıyaman and Şanlıurfa were evaluated with some biochemical data in the carp living in the lake and consumed economically by the public. Water, sediment and fish samplings were done simultaneously from Kahta and Bozova districts, where the Atatürk Dam Lake is located. Residue analyzes of various metals in water, sediment and muscle of carp samples were carried out together with some physicochemical parameters in the water. Total antioxidant capacity (TAC) and total oxidant scavenging capacity (TOSC) levels in liver, and activities of Na+/K+ATPase, Mg2+ATPase, Ca2+ATPase were determined in gill of the carp. As a result of the study, it was observed that Cd, Cr and Cu levels in water, Cd and Cu levels in sediment and Pb and Cd levels in carp exceeded the maximum acceptable concentrations. Among the biochemical parameters, oxidative stress index and TOSC level were found significantly higher in the liver of the fish in Kahta compared to those in Bozova. Na+/K+ATPase activity was significantly inhibited in the gill of the fish in Kahta. When all these pollution parameters and biochemical data are evaluated together, it can be said that the water, sediment and carp of Kahta are more contaminated with toxic metals than those in Bozova, and the carp are under oxidative stress, so they may be a threat to the health of the consumers hunted from this region.

Long-term seasonal and temporal changes of hydrogen peroxide from cyanobacterial blooms in fresh waters

In water, hydrogen peroxide (H2O2) is produced through abiotic and biotic reactions with organic matter, including algal cells. The production of H2O2 is influenced by harmful algal cell communities and toxicity. However, only a few studies have been conducted on H2O2 concentrations in natural water. Particularly, the seasonal and temporal patterns of H2O2 concentration suggest that H2O2 generation from aquatic microorganisms could be identified to compare of photochemical production from dissolved organic matter. Study area is a source of raw water and is a large artificial lake located near a metropolitan city. Due to various environmental conditions, harmful algal blooms frequently occur in summer. The purpose of this study was to trace the H2O2 concentration and water quality parameters of study area where algal bloom occurs and what factors directly affect the H2O2 concentration. Experiments were performed on the influencing factors via water samples from study area and lab-scale culture tank. The lake produces an average of 553 nM H2O2, which increases by more than three times (1460 nM) in summer compared the winter. The lake (18.6–23.8 nMh−1) produced more H2O2 than streams (7.4–9.0 nMh−1) during daylight hours. All water sites presented the lowest production rates in dark conditions (1.1–1.5 nMh−1). Daytime environment increased the generation rate more than the nighttime. The trend of H2O2 produced by algal cells was similar to that of the growth of algal cells. The exposure to external substances (heavy metals and antibiotics) increased the incidence by approximately five times; antibiotics were more influential than heavy metals.

Impact of a large artificial lake on regional climate: A typical meteorological year Meso‐NH simulation results

AbstractLarge artificial lakes and reservoirs affect the meteorological regime of the shore area and the local climate takes on a number of new features that were previously absent. This work focuses on the weather impact of the Alqueva reservoir, the largest artificial lake in Western Europe. An extensive set of numerical simulations using Meso‐NH mesoscale atmospheric model coupled with FLake (Freshwater Lake) scheme was carried out. The simulations covered a 12‐month period that was chosen to compose a so‐called Typical Meteorological Year. This artificial time period is meant to represent the typical meteorological conditions in the region and the model results are used to assess the changes in the local climate. To evaluate the raw impact of the reservoir, two different scenarios of simulations were compared: (A) with the reservoir as it exists nowadays and (B) without the reservoir using the older surface dataset. The results show decrease of air temperature during daytime (10–9°C) and nighttime increase (up to 10°C). In nearest towns, daily maximum temperature decreased and daily minimum temperature increased, which refers to milder weather conditions. Alqueva mainly showed suppression in fog formation in the nearby area. Local breeze regime was studied and monthly lake/land breezes were described.

Production Trends, and Challenges for Biodiversity Conservation and Sustainable Fisheries Management of Kaptai Lake, the Largest Reservoir in Bangladesh

Kaptai Lake (KL), the largest artificial lake in Bangladesh, supports an important inland open water fishery. Nevertheless, detailed studies on its fish diversity and environmental threats are still limited. Hence, a study was conducted to evaluate the current fish management scenarios, fish production, relative abundance to improve the production and biodiversity of KL. Data were collected from stakeholders through personal observation, focus group discussions, and cross-check interviews from September 2018 to July 2019. The fish production of KL increased from 1,200 metric tons (MT) in 1965–1966 to 10,577 MT in 2018–2019. The output of the lake was dominated by small fish remarkably, Gudusia chapra (Hamilton, 1822), Gonialosa manmina (Hamilton, 1822), and Corica soborna Hamilton, 1822, accounting for 64 % of the total production in 2018–2019. A total of seventy-six fish species were observed under ten orders, including seven exotic fish species. According to the IUCN Bangladesh, 14 % of total species were identified as vulnerable, 11 % as endangered, 3 % as critically endangered, 11 % as near threatened and 51 % as least concern. The study also identified that climate change and various human-driven causes threaten the fish production and biodiversity of this lake. These findings suggest that community-based fisheries management, protection of natural breeding grounds of carps, control of pollution, amendment of existing fishing laws, and collaborative research would be a necessary approach for mitigating the negative environmental impact of this lake. The overall practical knowledge of this investigation could assist in policymaking and further research.

Spatial Differences in Water Quality and Spatial Autocorrelation Analysis of Eutrophication in Songhua Lake

To identify the spatial differences in the water quality and eutrophication characteristics of Songhua Lake, the largest artificial lake in northeast China, analysis of variance (ANOVA) and factor analysis were used to analyze the water quality sampling and testing results in 2017 in three regions, namely the main reservoir area of the Fengman Reservoir (MRAFR), the experimental area of the Songhua River Three Lakes Protection Zone (EASRTLPZ), and the Jiaohe River backwater area (JRBA). The nutrient status of the lake was evaluated by the trophic state index method, and the spatial correlation and aggregation status of the eutrophication level in Songhua Lake were studied using spatial autocorrelation analysis. The main results were as follows: ① the ANOVA showed that, except for dissolved oxygen and chlorophyll-a (Chl-a), there were significant differences (P<0.05) in the total nitrogen (TN), total phosphorus (TP), water temperature (WT), and pH in the three areas of Songhua Lake, with the clearest difference between TN and TP. ② The factor analysis showed that the changes in the climatic condition factor (WT), nutrient salt factors (TN and TP), and algal biomass factor (Chl-a) dominated the water quality in the lake. ③ The results of the trophic state index showed that the nutrient status of Songhua Lake as a whole is mildly eutrophic, and the eutrophication levels of the three regions from strong to weak are JRBA > MRAFR > EASRTLPZ. ④ The global spatial autocorrelation showed that the eutrophication level of the lake as a whole has significant positive spatial autocorrelation owing to the influence of regional eutrophication levels. The spatial heterogeneity of the eutrophication level of Songhua Lake is low. ⑤ The results of the local spatial autocorrelation showed that the central and northern areas of JRBA are the hot spots (high/high concentration) of eutrophication in the lake (P<0.01), and the central part of EASRTLPZ is the cold spot (low/low concentration) of eutrophication in the lake (P<0.05). Therefore, when conducting water environmental management of Songhua Lake, the key areas for eutrophication control should be the JRBA and MRAFR.

Lake Modeling Reveals Management Opportunities for Improving Water Quality Downstream of Transboundary Tropical Dams

AbstractWater quality in tropical rivers is changing rapidly. The ongoing boom of dam construction for hydropower is one of the drivers for this change. In particular, the stratification in tropical reservoirs induces oxygen deficits in their deep waters and warmer surface water temperatures, which often translate into altered thermal and oxygen regimes of downstream river systems, with cascading consequences for the entire aquatic ecosystem. Operation rules of reservoirs, involving water intakes at different levels, could mitigate the consequences for downstream water quality. However, optimized water management of deep reservoirs relies on predictive models for water quality, but such predictive capability is often lacking for tropical dams. Here we focus on the Zambezi River Basin (southern Africa) to address this gap. Using the one‐dimensional General Lake Model, we reproduced the internal dynamics of the transboundary Lake Kariba, the world’s largest artificial lake by volume, created by damming the Zambezi River at the border between Zambia and Zimbabwe. Through this modeling approach, we assessed and quantified the thermal and oxygen alteration in the Zambezi River downstream of the reservoir. Results suggest that these alterations depend directly on Kariba’s stratification dynamics, its water level and the transboundary policies for water withdrawal from the reservoir. Scenario calculations indicate a large potential for mitigating downstream water quality alterations by implementing a hypothetical selective withdrawal technology. However, we show that a different and cooperative management of the existing infrastructure of Kariba Dam has the potential to mitigate most of the actual water quality alterations.

Climate Services for Water Resource Management in China: The Case Study of Danjiangkou Reservoir

The efficiencies and effectiveness of water resource management are inextricably linked to climate services. This study demonstrates a climate information service for Danjiangkou Reservoir, which is the largest artificial lake in Asia, facing mounting challenges for flood control, water storage, and water diversion. Unlike traditional water resource management on the basis of short-term weather forecast and runoff monitoring, subseasonal to seasonal (S2S) and annual climate predictions as well as long-term climate change projections were well used to support the decision makers in Danjiangkou Reservoir. The National Climate Center (NCC) has projected the changes of future climate and extreme events by dynamically downscaling the Coupled Model Intercomparison Project phase 5 (CMIP5) projections to 25-km resolution for the long-term planning of water resource management in Danjiangkou Reservoir. Real-time climate predictions based on climate models and downscaling interpretation and application methods at different timescales were also provided to meet the specific needs of earlier predictions and spatial refinement for the short-term diversion of the reservoir. Our results show that such climate services facilitated the Diversion Center of Danjiangkou Reservoir (DCDR) to reasonably control the operational water level, increased the ecological water supply to the northern portion of China by 844 million m3, and reduced as much as 1.67 billion m3 of abandoned water in 2019. In the future, it is necessary to develop climate prediction methods to increase spatial and temporal resolutions and prediction skills, and enhance interactions between providers and users.

Numerical study of the seasonal thermal and gas regimes of the largest artificial reservoir in western Europe using the LAKE 2.0 model

Abstract. The Alqueva reservoir (southeast of Portugal) is the largest artificial lake in western Europe and a strategic freshwater supply in the region. The reservoir is of scientific interest in terms of monitoring and maintaining the quality and quantity of water and its impact on the regional climate. To support these tasks, we conducted numerical studies of the thermal and gas regimes in the lake over the period from May 2017 to March 2019, supplemented by the data observed at the weather stations and floating platforms during the field campaign of the ALentejo Observation and Prediction (ALOP) system project. The 1D model, LAKE 2.0, was used for the numerical studies. Since it is highly versatile and can be adjusted to the specific features of the reservoir, this model is capable of simulating its thermodynamic and biogeochemical characteristics. Profiles and time series of water temperature, sensible and latent heat fluxes, and concentrations of CO2 and O2 reproduced by the LAKE 2.0 model were validated against the observed data and were compared to the thermodynamic simulation results obtained with the freshwater lake (FLake) model. The results demonstrated that both models captured the seasonal variations in water surface temperature and the internal thermal structure of the Alqueva reservoir well. The LAKE 2.0 model showed slightly better results and satisfactorily captured the seasonal gas regime.