River Lake Research Articles

Water Resources Management for Multi-Source Ecological Restoration Goals in an Oasis: A Case Study of Bohu County Irrigation Area in Xinjiang, China

Oases in arid regions consist of river–lake–groundwater systems characterized by complex hydrological cycles and fragile ecosystems. Sustainable water resource management, aimed at multi-source ecological restoration, is crucial for oasis ecological protection and represents a current research challenge. This study focuses on the Bohu irrigation area, using ecological water levels, the MIKE-SHE hydrological model, and the water balance equation to propose a multi-objective groundwater and surface water regulation scheme that meets both the ecological safety requirements of the irrigation area and the ecological water demands of the Small Lake. Key findings include the following: (1) The regional ecological water level ranges from 1.69 m to 4 m, with about 74% of the area exceeding this range, threatening local ecology. (2) The proposed regulation method adjusts 91.25% of areas exceeding the ecological water level to within the acceptable range. (3) Under various planting scenarios, the minimum water distribution from the west branch of the BLSM water diversion hub should be 824.632 × 106 m3/a to meet Small Lake ecological demands. When this volume exceeds 831.902 × 106 m3/a, both groundwater regulation and Small Lake ecological demands are satisfied. This paper quantifies the water cycle mechanisms in complex hydrological interaction areas, providing specific solutions to regional ecological problems, which holds significant practical relevance.

Enhancing the freshness of particulate organic carbon through the regulation of dam and river-lake interactions

The composition and fluxes of organic carbon transported by river systems are important for the terrestrial carbon cycle in terms of source to sink, and the impacts of dam regulation on large rivers are well documented. However, complex river–lake interactions and extreme weather events still hinder a comprehensive understanding of the transformation of riverine carbon within the large river basin. This study investigated particulate organic matter during the 2012 flood in the Changjiang Basin (CJB) and collected suspended particles from the mainstream of the CJB, Dongting and Poyang lakes. The amount, grain size, particulate organic carbon (POC) content, chlorophyll a (Chl-a), and lignin phenols of samples were measured. The results indicate that soil is the primary source of POC in lake-unaffected stations (46.9%–86.9%), while lake-affected stations exhibit significant contributions from phytoplankton (41.4%–78%). Notable alterations in the composition of terrestrial organic carbon occur during its transfer from soil to the river and from the upper to the lower reaches. Comparing the POC characteristics in the Changjiang across various years and hydrological conditions reveals that the characterization of POC in the Changjiang during flooding is mainly influenced by the dams. Another notable finding is that Dongting and Poyang lakes intercepted sediment and transported algae-rich organic matter to the mainstream. This process potentially converts the middle reaches of the Changjiang into a carbon source. River-lake interactions are complex and affected by lake morphology and flooding events. This study enhances our understanding of biogeochemical processes in dam-regulated rivers under extreme weather conditions, and emphasizes the importance of river–lake interactions for the transformation and transportation of riverine organic carbon in large fluvial system.

Correction: Comparative effects of river–lake disconnection on taxonomic and functional composition of molluscan assemblages in floodplain lakes

Correction: Comparative effects of river–lake disconnection on taxonomic and functional composition of molluscan assemblages in floodplain lakes

Comparative effects of river–lake disconnection on taxonomic and functional composition of molluscan assemblages in floodplain lakes

Comparative effects of river–lake disconnection on taxonomic and functional composition of molluscan assemblages in floodplain lakes

Effect of Irrigation Water Quality on Selected Soil Physico-Chemical Properties in Ethiopia: Review

Saline and sodic water qualities used for irrigation could deteriorate soil physico-chemical properties based on type and amount of salts present in irrigation water and soil type being irrigated. Irrigation water with marginal quality could lead to the buildup of new soil characteristics that affect its fertility and productivity. In line with these issues, this review paper focused on reviewing the effect of irrigation water quality on selected soil physico-chemical properties in Ethiopia. Consequently, irrigation water quality of Errer River of Babile District, Ground water of Babile District, Tumuga and Gerjale irrigation sources, Adamitulu surface and ground water, Abaya Lake water, mixed water (Awash River to Beseka Lake River) and effect of these water sources qualities on selected soil physico-chemical properties were reviewed. The Errer River of Babile District, Tumuga and Gerjale irrigation water quality extent were within and below permissible value based on degree of restriction on use for irrigation and some selected soil physicochemical properties weren’t affected in observable extent due to quality of irrigation water. Certain irrigation water quality extent implied that Ground water of Babile District, Adamitulu Surface and Ground water, Abaya Lake water, mixed water (Awash River to Beseka Lake River) problem of suitability for irrigation and some selected soil physicochemical properties were affected due to extent of irrigation water quality were above threshold limit of irrigation water quality. The reviewed papers indicated that the soil quality was affected due to quality of irrigation water like its quality extent of salinity (EC), sodium adsorption ratio (SAR), residual sodium carbonate (RSC) and soluble sodium percentage (SSP) as it increased sodium, salt level and salinity in soil due to these parameters of irrigation water quality were above threshold limit, but calcium, magnesium and organic matter particulate content of irrigation water could improve soil fertility. Therefore, monitoring of irrigation water quality and checking of pre-planting and after harvesting soil physicochemical properties is very crucial to reveal and monitor the effect of irrigation water quality on soil physico-chemical properties.

Zooplankton functional diversity as a bioindicator of freshwater ecosystem health across land use gradient

Zooplankton are critical indicators of pressures impacting freshwater ecosystems. We analyzed the response of zooplankton communities across different sub-catchment types—headwaters, natural, urban, urban-agricultural, and agricultural—within the Łyna river–lake system in Northern Poland. Using taxonomic groups and functional traits (body size, feeding strategies), we applied Partial Least Squares Regression (PLS-R) to elucidate the relationships between environmental conditions, land use, and zooplankton metacommunity structure. Two-Way Cluster Analysis (TWCA) identified local subsets with characteristic patterns, while Indicator Species Analysis (ISA) determined area-specific taxa. The natural river zone exhibited significant habitat heterogeneity and feeding niches, whereas urban areas created functional homogenization of zooplankton, dominated by small, broad-diet microphages. Agricultural areas promoted diversity among large filter feeders (Crustacea), active suctors (Rotifera), and amoebae (Protozoa). However, intensified agricultural activities, substantially diminished the zooplankton population, biomass, taxonomic richness, and overall ecosystem functionality. The impact of land cover change is more pronounced at small-scale sub-catchments than at the catchment level as a whole. Therefore, assessing these impacts requires detailed spatial and temporal analysis at the sub-catchment level to identify the most affected areas. This study introduces a new sub-catchment-based perspective on ecosystem health assessment and underscores the zooplankton's role as robust indicators of ecological change.

Environmental DNA in different media reveals distribution characteristics and assembly mechanisms of fish assemblages in a complex river–lake system

Environmental DNA in different media reveals distribution characteristics and assembly mechanisms of fish assemblages in a complex river–lake system

Spatiotemporal pattern of water age in Dongting Lake before and after the operation of the Three Gorges Project

Study regionDongting Lake Basin of China. Study focusDongting Lake is the first large-scale interconnected river–lake systems in the middle-lower reaches of the Yangtze River and the second-largest freshwater lake in China. Dam operation on the upper reaches of the Yangtze River dramatically affected the hydrological condition of Dongting Lake. Therefore, this study established a hydrodynamic-water age model to assess the effects of the Three Gorges Dam (TGD) on the spatiotemporal pattern of water age in Dongting Lake. New hydrological insightsThe results show a significant spatial and temporal variation of water age in Dongting Lake. Water age in the floodway is lower than that in the shoal, meanwhile, water age in spring and summer is lower than that in autumn and winter. By establishing a hydrodynamic-water age model, several factors influencing water age in Dongting Lake were analyzed, i.e., the influences of the Jingjiang Three Outlets' triage from the Yangtze River, the water level of the mainstream of the Yangtze River, and the flow pattern. The TGD could influence the water age in Dongting Lake by altering the hydrodynamic conditions of the Yangtze River. Results from this study provide support for flood control and dispatch management of Dongting Lake and provides a reference for water exchange studies in other large shallow lakes.

Lateral connectivity maintains higher freshwater mussel biodiversity

Abstract The loss of lateral hydrological connectivity (LLHC) in freshwater ecosystems is increasingly threatening biodiversity; however, studies reporting this situation are limited, especially those assessing multi‐measure biodiversity features at large spatial scales. Here, and using one the most threatened taxonomic groups in freshwater ecosystems, we examined the possible influence of LLHC on the species diversity, density, and biomass of mussel assemblages and the genetic diversity and structure of Nodularia douglasiae (a common and widespread native species) in the Yangtze River floodplain. Results showed that the species diversity of freshwater mussels (α and β diversity) significantly differed between the connected and the disconnected areas, with higher α diversity and lower β diversity in the connected areas. At the same time, relative abundance, density, biomass, and genetic diversity of freshwater mussels were higher in the connected areas. High genetic differentiation and low gene flow were found among the 18 analysed N. douglasiae populations, indicating that LLHC is affecting genetic structure of this particular freshwater mussel species. Overall, results indicated that river–lake connectivity is affecting freshwater mussel biodiversity. In addition, this study highlights that multi‐measure biodiversity features provide distinct information about biodiversity dynamics, and are essential to evaluate the effects of floodplain disconnection. We advocate that an integrative approach to floodplain management embracing species and genetic diversity is needed for effective biodiversity conservation in large river ecosystems.

Late Quaternary tectonic uplift and Yellow River evolution create high arsenic aquifers in the Hetao Basin, China

High arsenic (As) groundwater is a global problem primarily originating from As-enriched sediments. The provenance (source) and release mechanisms (sinks) of high As sediment have been identified, but the source-sink transfer is poorly understood, especially the influence of geological and surface processes. In this study, we explore the roles of tectonic movement and Yellow River evolution in provenance formation processes and evaluate the combined effects of provenance and sediment age on the As content of aquifer sediments in the northern Hetao Basin of Inner Mongolia. Based on optically stimulated luminescence (OSL) and 14C dating and detrital zircon U-Pb, As content, and lithological analyses of a 400 m core, we reconstructed As changes over the last 160 ka. Our results show clay deposited in a paleo-lake during the Gonghe movement period in the late Pleistocene (∼100 ka B.P.) is enriched in As (31.8 μg/g) due to significant provenance contributions of the As-bearing Langshan Group under tectonic uplift and mountain erosion. In contrast, clay deposited in the middle Pleistocene (∼160 ka B.P.) has lower As content (7.3 μg/g) due to the Yellow River as the primary provenance. Accordingly, the provenance of basin As forced by tectonic uplift and Yellow River evolution determines the background As of aquifer sediments. After deposition, sediment As content decays over time, with higher decay rates in coarse-grained sands than fine-grained. Overall, both provenance formation and sediment age, representing initial and dynamic states of solid phase As, jointly determine the As content of aquifer sediments. More solid phase As provided by younger sediments from the proximal orogenic provenance and reducing conditions due to frequent river–lake transitions, jointly lead to higher As concentrations in shallow groundwater. The study highlights the potential for using a combined analysis of the tectonic movement-surface processes-environment system to improve understanding of geogenic high As groundwater over global large sedimentary basins in the proximity of young orogenic belts.

Hydraulic conditions control the abundance of antibiotic resistance genes and their potential host microorganisms in a frequently regulated river–lake system

Antibiotic resistance genes (ARGs) are a growing problem that is widespread in river–lake ecosystems, where they pose a threat to the aquatic environment's health and public safety. These systems serve as critical nodes in water management, as they facilitate the equitable allocation of water resources through long-term and frequent water diversions. However, hydrological disturbances associated with water-regulation practices can influence the dynamics of their potential host microorganisms and associated resistance genes. Consequently, identifying the key ARGs and their resistance mechanisms in heavily regulated waters is vital for safeguarding human health and that of river–lake ecosystems. In this study, we examined the impact of water-regulation factors on ARGs and their hosts within a river–lake continuum using 16S rRNA and metagenomic sequencing. We found that a significant increase in ARG abundance during regulation periods (p < 0.05), especially in the aquatic environment. Key resistance genes were macB, tetA, evgS, novA, and msbA, with increased efflux pinpointed as their principal resistance mechanism. Network analysis identified Flavobacteriales, Acinetobacter, Pseudomonas, Burkholderiaceae, and Erythrobacter as key potential host microorganisms, which showed increased abundance within the water column during regulation periods (p < 0.05). Flow velocity and water depth both drove the host microorganisms and critical ARGs. Our findings underscore the importance of monitoring and mitigating the antibiotic resistance risk during water transfers in river–lake systems, thereby supporting informed management and conservation strategies.

Ecosystem-level response to complex disturbances of an interconnected river–lake system based on Ecopath model over the last 30 years

Ecosystem-level response to complex disturbances of an interconnected river–lake system based on Ecopath model over the last 30 years

A transition zone boundary determining method based on MIKE21: A case study of Baiyangdian Lake, North China

River and lake ecosystems converge to form transition zones, which play a key role in the flow of organisms, matter and energy. Although the importance of transition zone has been gradually recognized, there is still a lack of unified understanding on the transition zone boundary determination. In this study, taking Baiyangdian Lake, North China as an example, we proposed a method for determining the transition zone boundary based on water quality gradient using MIKE21 software, in which the confluence of the river and the lake was taken as the upper boundary, and the lower boundary was determined according to the variation inflection point of the water quality gradient. Total nitrogen (TN) was selected as the critical parameter due to its key role and high percentage among inflow river pollution. The results showed that the transition zone ranges varied with inflow rates and TN concentrations, as well landforms, and the corresponding areas of three transition zones, namely Fu River-Baiyangdian Lake, Xiaoyi River-Baiyangdian Lake and Baigou Canal-Baiyangdian Lake were 37.92, 34.11 and 24.99 km2 under critical flow conditions respectively. And the transition zone boundary was stable when connected flow was higher than critical value. This study has explored a theoretical way of determining the boundary of the river–lake transition zones, thus providing a scientific basis for further research on water quality-ecological response and the optimal allocation of water resources in transition zone.

Flood Propagation Characteristics in a Plain Lake: The Role of Multiple River Interactions

Plain lakes play a crucial role in the hydrological cycle of a watershed, but their interactions with adjacent rivers and downstream water bodies can create complex river–lake relationships, often leading to frequent flooding disasters. Taking Poyang Lake as an example, this paper delves into its interaction with the Yangtze River, revealing the spatiotemporal patterns of flood propagation within the lake and its impact on surrounding flood control measures. The aim is to provide insights for flood management in similar environments worldwide. This study employs a comprehensive approach combining hydrological statistical analysis and two-dimensional hydrodynamic modeling, based on extensive hydrological, topographic, and socio-economic data. The results indicate that the annual maximum outflow from Poyang Lake is primarily controlled by floods within the watershed, while the highest annual lake water level is predominantly influenced by floods from the Yangtze River. The peak discharge typically reaches the lake outlet within 48 h, with the peak water level taking slightly longer at 54 h. However, water storage in the lake can shorten the time that it takes for the peak discharge to arrive. When converging with floods from the Yangtze River, the peak water level may be delayed by up to 10 days, due to the top-supporting interaction. Furthermore, floods from the “Five Rivers” propagate differently within the lake, affecting various lake regions to differing degrees. Notably, floods from the Fu River cause the most significant rise in the lake’s water level under the same flow rate. The top-supporting effect from the Yangtze River also significantly impacts the water surface slope of Poyang Lake. When the Yangtze River flood discharge significantly exceeds that of the “Five Rivers” (i.e., when the top-supporting intensity value, f, exceeds four), the lake surface becomes as flat as a reservoir. During major floods in the watershed, the water level difference in the lake can increase dramatically, potentially creating a “dynamic storage capacity” of up to 840 million cubic meters.

Coupled effects of human activities and river–Lake interactions evolution alter sources and fate of sedimentary organic carbon in a typical river–Lake system

Interconnected river–lake systems record sedimentary organic carbon (OCsed) dynamics and watershed environmental changes, providing valuable information for global carbon budgets and watershed management. However, owing to the evolving river–lake interactions under global change, monitoring OCsed is difficult, thereby impeding the understanding of OCsed transport and fate. This study provided new insights into the dynamical mechanisms of OCsed in a typical river–lake system consisting of Dongting Lake and its seven inlet/outlet rivers (the three inlets of the Yangtze River and four tributaries) over the last century using stable isotope tracing and quantified the influences of climate change and human activities on OCsed. Results indicated that exogenous OC dominated the OCsed in the lake (58.2 %–89.0 %) and was lower in the west than in the east due to the differences in the material inputs and depositional conditions within the lake. Temporally, the distribution patterns of OCsed sources mainly responded to human activities in the basin rather than to climate change. Before 2005, the Yangtze River contributed the most OCsed (53.5 %–74.6 %), attributed to the high-intensity land use changes (path coefficient (r∂): 0.48, p-value < 0.01) and agriculture-industry activities (r∂: 0.44, p-value < 0.001) in the Yangtze River basin that increased soil erosion. After 2005, a large amount of Yangtze River OC was intercepted by the Three Gorges Dam, altering the OC exchange in the river–lake system and shifting OCsed dominance to the four tributaries (52.2 %–63.8 %). These findings highlight the active response of OCsed to the river–lake interaction evolution and anthropogenic control, providing critical information for regulating watershed management behavior under global change.

Hydrodynamic response of a large river–lake system under flow regulation: A numerical study of Hongze lake

The hydrodynamic processes in large river–lake systems and their responses to flow regulation represent regionally unique and highly significant issues. This study presents the implementation, validation and application of a two-dimensional hydrodynamic model to a system comprising a section of the Huai River and Hongze Lake, China. The validated model enabled the identification of hydrodynamic characteristics by analysing the flow patterns under the influence of the local flow regulation. Effective flow regulation measures during flood period reduced the retention time of floodwater in the lake and contributed to a low-velocity current field in the northern part of the river–lake system. Throughout the non-flood period, a distinctive flow pattern emerged due to persistent easterly winds, resulting in a dual circulation pattern in the interconnected region between the northern and central segments of the system. The investigation of flow patterns revealed the creation of stagnant water zones in the northern sector of Hongze Lake. Distributing a substantial portion of outflow discharge to the Erhezha gate could lead to an expansion of the flood passing area by scenario analysis. Simultaneously, implementing intermittent control over the Erhezha gate drainage effectively heightened the current velocities in the stagnant water zone. The deliberate allocation of outflow discharge has a substantial impact on the flow dynamics within a vast river–lake system during the flood season, which carries significant research potential in enhancing the local water self-purification capacity and water quality.

Diagnosis of the Condition of Aquatic Ecosystems Using a Partial Assessment of Ecological and Trophic States: An Example of Small Lakes in Northern Poland

The current state of aquatic ecosystems was assessed for lakes in two river–lake systems: Święta Struga (Święte and Ocypelek) and Kałębnica (Czarne Południowe and Kałębie). Trophic states were determined using the Vollenweider, Nürnberg, and Carlson methods. Additionally, shoreline changes were analyzed for all lakes concerning their natural character, and physicochemical parameters were utilized as auxiliary elements in the assessment of the ecological state following the guidelines of Directive 2000/60/EC. Supplementary to these methods, the ecological evaluation of the littoral zone utilized meiobenthic organism grouping as an indicator. The results indicate significant differences among the studied reservoirs. Lake Święte is a reservoir bordering mesotrophy and eutrophy, with the ecological state of the littoral zone showing ongoing trophic development. Lake Ocypelek exemplifies a eutrophic reservoir undergoing progressive degradation. The lakes in the Kałębnica system also exhibit advanced trophic conditions, with Lake Kałębie being a eutrophic reservoir. Its shoreline has been significantly altered due to the development of the direct catchment area. In contrast, Lake Czarne Południowe serves as an example of a mesotrophic reservoir, with a substantially changed shoreline. Considering physicochemical elements and chlorophyll a concentration, the water quality for all examined lakes was found to be below the good category. The diagnosis of the condition of lake aquatic ecosystems requires an individualized approach to each of them. Therefore, employing various methods for their assessment, encompassing physico-chemical, biological, and morphological parameters, provides the opportunity to initiate potential remedial actions that will effectively contribute to their improvement. Conducting low-cost research involving a multidisciplinary approach to diagnose the state of aquatic ecosystems is becoming a crucial element in lake monitoring.

Size‐dependent community patterns differ between microbial eukaryotes and bacteria in a permafrost lake–river–sea continuum

AbstractMicrobial communities play a crucial role in ecosystem functioning, with contributions that can vary among taxonomic domains and size fractions. However, microbial assembly processes for bacteria and eukaryotes are seldom characterized together using size fractionation, especially in flowing waters. Here, we used amplicon sequencing combined with physicochemical measurements to determine how size fractionated (small fraction 0.22–3 μm; large fraction &gt; 3 μm) community structure and diversity varied over a subarctic river continuum. We sampled the Sheldrake River, a 25 km river flowing through degrading discontinuous permafrost, from its lacustrine source through subarctic forest shrub tundra to its discharge plume in eastern Hudson Bay (Nunavik, Canada). Microbial community structure differed by size fraction and among habitats, with differences in the variables potentially driving community structure among size fractions and microbial domains. For the small size fraction, colored dissolved organic matter was a significant covariate of community variation for both bacteria and eukaryotes, consistent with the influence of landscape gradients. There were contrasting diversity patterns along the lake–river transect between bacterial size fractions. An abundance‐based approach indicated that for all communities, assembly processes were dominated by homogeneous selection, while an incidence‐based method showed dominance of heterogeneous selection for bacteria and homogenizing dispersal for microbial eukaryotes. Our findings show how different components of riverine microbial communities can have divergent patterns along the downstream continuum to the sea.

The “Aniangzhai” ancient dammed lake discovered on the eastern margin of the Tibetan Plateau

Ancient dammed lake deposits, developed in tectonically active mountainous areas, record high-resolution changes in paleoclimate and paleoseismicity. This paper reports a massive ancient dammed lake, the “Aniangzhai paleolandslide-dammed lake”, newly discovered in the upper reaches of the Dadu River on the eastern margin of the Tibetan Plateau. Optically stimulated luminescence (OSL) dating showed that this lake formed prior to 15.7 ± 1.9 ka and persisted for 7 ka. The basic properties of lacustrine sediments and abnormal fluvial deposits of the dammed lake were identified through field sedimentological investigation and use of unmanned aerial vehicle (UAV) technology. Through a literature review of reservoir siltation, several methods of estimating the dam surface elevation were summarized, and on this basis, the Aniangzhai paleolandslide and ancient dammed lake were reconstructed. The results indicated that the Aniangzhai ancient dammed lake extended for 79 km upstream, with a maximum sediment thickness of 128 m. The lake at one time held back an area and volume of water of 53.5 km2 and 5.74 × 109 m3, respectively. This study proposed the fluvial-dammed lake sedimentary zoning system of ancient dammed lakes based on changes in sedimentary characteristics among different sections: (1) deep–semi-deep lake; (2) shallow lake; (3) lakeshore; and (4) area of river–lake intersection. This study also discussed a general, but systematic and novel model under which ancient dammed lakes in mountainous areas evolve. It may provide new information on the evolution of the paleoclimatic environment in the eastern Tibetan Plateau after the Last Glacial Maximum.

A framework for analysing water security of Tonle Sap Lake in the Mekong River basin: Flow, volume, inundation, productivity and livelihoods

AbstractWater is a scarce resource globally, and a water shortage worldwide would cause water security. Although there is plenty of literature studying water security, many discuss water security concerning water quality that is harmful to human health, some on the floods and droughts which destroy agriculture and livelihoods of people, and others on water war or water conflict in transboundary river basin; but little discusses water security concerning changing river flow, volume, inundation, productivity and livelihoods in the river–lake system (RLS). Thus, this paper studies the RLS to examine how changes in river flows and the volumes of the water in the RLS would affect the inundation and productivity of the RLS and, later, the livelihoods of river–lake people (RLP). In answering this question, the article undertakes the literature review and the case study of Tonle Sap Lake (TSL) in Cambodia to examine this form of water security. The paper concludes that the RLS has a close relationship between the flow, volume, inundation and productivity of fisheries and people's livelihoods. The hydropower dams, urban development and climate change cause the disconnectivity and the discontinuity of the river–lake flow, volume and inundation, undermining the productivity of fisheries and livelihoods of river–lake‐dependent communities. There is a strong need for cooperation and coordination between riparian states in the Mekong River Basin (MRB) to maintain the secured flow and volume in the Mekong River (MR) and TSL and protect the livelihoods of RLP.