Qiuwen Chen

Nanjing Hydraulic Research Institute | NHRI · Center for Eco-Environmental Research

Increasing algal blooms in freshwater lakes have become a serious challenge facing the world. Short-term forecast of chlorophyll-a concentration (Chla) is essential for providing early warnings and taking action to mitigate the risks of algal blooms in freshwater lakes. At present, a variety of data-driven models and physical-based models have been...

Flow and water surface elevation recession rate Regulated and unregulated flows Dam operation A B S T R A C T Fish can be stranded in pools during flow recessions that may occur naturally or as a result of dam operations. Past studies have recommended dam operation guidelines that only consider water surface elevation (WSE) recession rate to reduce...

Climate change has remarkable effects on the hydrological regime in floodplain wetlands. However, the hydrodynamic simulation under climate change conditions suffers from the uncertainty of the downstream water level boundary. In this study, an effective approach was developed by integrating an advanced machine learning algorithm and a process-base...

Using unregulated tributaries to compensate fish habitat loss in dammed mainstreams has recently been suggested as a promising strategy for river ecological restoration. One critical prerequisite is to find potential tributaries as alternative habitat, which depends on precise fish community surveys. In this study, both eDNA metabarcoding and elect...

Exploring the response between benthic community changes and environmental variables has significance for restoring the health of river ecosystems. However, little is known of the impact on communities of interactions between multiple environmental factors, and frequent changes in the flow of mountain rivers are different from those in the flow of...

It is typical to use a single portion of the available data to calibrate hydrological models, and the remainder for model evaluation. To minimize model‐bias, this partitioning must be performed so as to ensure distributional representativeness and mutual consistency. However, failure to account for data sampling variability (DSV) in the underlying...

ZnO nanoparticles (ZnO NPs) have been applied in a wide range of fields due to their unique properties. However, their ecotoxicological threats are reorganized after being discharged. Their toxic effect on anadromous fish could be complicated due to the salinity fluctuations during migration between freshwater and brackish water. In this study, the...

Land use and land cover (LULC) have significant impacts on river water quality, particularly in regions subjected to rapid urbanization. However, it is unclear whether LULC (LULC type and pattern index) can be used as an effective indicator to predict water quality over the rapid urbanization regions. Here, we investigated the spatiotemporal change...

Field investigation indicated that the reduction in fish spawning was associated with the alteration in water temperatures, even a 2–3 °C monthly difference due to reservoir operations. However, the physiological mechanism that influences the development of fish ovary (DFO) remains unclear. Thus, experiments of Coreius guichenoti were conducted at...

Hydraulic connectivity has great effects on water quality. Enclosure aquaculture can largely alter lake flow regime and thus deteriorate water quality. Understanding the dynamics and influencing factors of water quality in enclosure aquaculture lakes is of great significance to ecosystem restoration of degraded lakes. However, it remains challengin...

Antibiotic stewardship is hindered by a lack of consideration for complicated environmental fate of antibiotics and their role in resistance development, while the current methodology of eco-toxicological risk assessment has not been fully protective against their potential to select for antibiotic resistance. To address this problem, we establishe...

Floodplains play essential roles in the ecological functions of regional environments. The merging and coalescence of bacterial communities in aquatic environments results in periodic patterns driven by regular hydrological activities, which may, in turn, influence ecological activities. However, the degree of bacterial community coalescence in the...

Climate change threatens biodiversity through global alteration of habitats, but efficient conservation responses are often hindered by imprecise downscaling of impacts. Besides thermal effects, warming also drives important ancillary environmental changes, such as when river hydrology evolves in response to climate forcing. Earlier snowmelt runoff...

Periodic flooding in floodplain wetlands dominates the landscape pattern, creating rich and diverse habitats for waterbirds. However, most studies on floodplain wetland landscape are conducted at interannual scale, while few researches investigate the effect of short‐term changes of hydrological components, such as maximum continuous flooding day,...

Cyanobacterial blooms challenge the safe water supply in estuary reservoirs. Yet, data are limited for the variation of phytoplankton dynamics during an algal bloom event at refined scales, which is essential for interpreting the formation and cessation of blooms. The present study investigated the biweekly abundances and dynamics of pico- and nano...

The livestock breeding industries face overuse of antibiotics, which has been intensively studied in recent years. However, the occurrence and fate of antibiotics as well as their potential threats to the aquatic environments in alpine and arid regions remain unclear. This study investigated the relationship of the occurrence and concentrations of...

Large water resource projects may severely alter hydrological regimes and thus the habitat conditions for biota in wetlands. Plenty of habitat models for fish, vegetation, and invertebrates have been developed and widely used; however, there is a lack of effective models to assess the effects of water resource projects on waterbird habitat in wetla...

In this paper, two trophic lakes: Lake Taihu and Lake Yanghe, and three alpine lakes: Lake Qinghai, Lake Keluke, and Lake Tuosu, were investigated to discover the connections between environmental factors and the phytoplankton community in lakes with differences in trophic levels and climatic conditions. Three seasonal data, including water quality...

Error estimation and data fusion are critical to improving the accuracy of global model- and satellite-based precipitation products for practical applications. However, they face challenges over vast areas of the world due to limited ground observations. Triple collocation (TC) method can overcome this limitation and provide an efficient way for er...

Endocrine-disrupting compounds (EDCs) enter lakes mainly through river inflow. However, the occurrence, transport and fate of EDCs in the overlying water, suspended particulate matter (SPM) and sediment of inflowing rivers remain unclear. This study investigated the load of seven EDCs in a complex river-lake system of the Taihu Lake Basin during di...

Methylmercury (MeHg) can be bioaccumulated through food chains and adversely affect human health. Reservoirs are reported to stimulate MeHg production, however, the characteristics of MeHg dynamics in cascade reservoirs and the associated relations to sedimentation as well as reservoir properties remained unclear. Here we investigated sediment MeHg...

Quantitative predictions of total dissolved gas (TDG) super-saturation are essential for developing operation schemes for high dams. Most TDG generation prediction models have various shortcomings that affect the accuracy of TDG super-saturation estimation, such as oversimplification of influencing factors and uncertainty in parameter values. In th...

China's current water quality standards (WQS) were first established in the 1980s referring the other countries' experience in setting environmental criteria and may not be suitable for the circumstances in China. Thus, it is necessary to improve the theories and methodologies of WQS. This paper provided a promising method to determine water qualit...

Dam construction is widespread, changing the hydrological and biogeochemical conditions and thereby the bacterial communities in the rivers of the earth. To date, knowledge is lacking about bacterial communities in cascade reservoirs. Here, we investigated the bacterial communities and potential functions of nine cascade hydropower reservoirs in 12...

Purpose In complex watersheds with multiple types of waterbodies, the effect of river damming on the distribution pattern of heavy metals in sediments and their potential ecological risks are inconsistent, leading to an inability to accurately manage heavy metal pollution. The aim of this study was to reveal the driving mechanisms of hydropower res...

Iron salts are increasingly employed in wastewater treatment worldwide, generating ferric phosphate sludge with low phosphorus (P) bioavailability. The fermentation of ferric phosphate sludge effectively transfers P from the solid phase to the liquid phase and simultaneously releases high contents of ferrous cations (Fe²⁺) and humic acids (HA) into...

Understanding the relation between landscape pattern and water quality is essential to making a master plan for restoration of regional lake and wetland clusters, which has not yet been well resolved. Here, we studied the impacts of landscape pattern changes on water quality over lake clusters, taking the aquaculture area in the Lixia River hinterl...

A novel multi-source data fusion method based on Bayesian inference (BIF) was proposed in this study to blend the advantages of in-situ observations and remote sensing estimations for obtaining accurate chlorophyll-a (Chla) concentration in Lake Taihu (China). Two error models (additive and multiplicative) were adopted to construct the likelihood f...

In this study, we have investigated the purification efficiency during enhanced coagulation, ozone oxidation and their combined processes for the removal of trace amounts of EDCs in different DOM matrices. The results indicated that the maximum removal efficiency of EDCs occurred at or near pH 7.0 when measured over a pH range of 4.0–10.0. The addi...

Both cyanobacterial bloom and antibiotic resistance have aggravated worldwide and posed a global threat to public health in recent years. Cyanobacteria can exhibit discrepancy between their resistance genotype and susceptible phenotype due to antibiotic heteroresistance, which leads to difficulties in unambiguously classifying cyanobacterial strain...

Flooding has been one of the major issues that have seriously hampered the developments of the urban systems, as well as threatened the urban water environments. To mitigate the impacts of floods, it is highly important to identify effective evacuation plans with the aid of computer-based methods. However, effectively identifying the dynamic evacua...

Current expectation is that projected climate change may have adverse effects on fish habitats and survival. The analysis leading to these concerns is typically done at large scale with limited possibility to quantify the local biological response and compare with previous conditions. Our research investigated the effects of recorded climate condit...

In dammed rivers, sediment accumulation creates potential methane emission hotspots, which have been extensively studied at sediments deposited on the riverbed. However, methane emissions from sediment deposited riparian zones at the land‐water interface remain poorly understood. We investigated the spatial pattern of diffusive methane emissions fr...

Cascade dams segment river connectivity, modify the hydrological process, and change the hydraulic properties, thus influencing the river ecosystem significantly. Ecological effects of dams have been extensively studied, but investigations on zoobenthos in a large area covering tributaries and mainstream with cascade dams are lacking. Here, we stud...

Toxic cyanobacteria bloom is a ubiquitous phenomenon worldwide in eutrophic lakes or reservoirs. Microcystis, is a cosmopolitan genus in cyanobacteria and exists in many different forms. Microcystis aeruginosa (M. aeruginosa) can produce microcystins (MCs) with strong liver toxicity during its growth and decomposition. Phosphorus (P) is a typical g...

Dam removal has been widely used as a river restoration approach; however, the effectiveness of removing low-head dams in tributaries for fish habitat compensation in a dammed river is still poorly understood. One major impediment to examining the ecological effectiveness of low-head dams is the short length of post-dam hydrologic, geomorphic and e...

Dam operations considerably influence water temperature regimes in rivers, which affects fish spawning activities. Previous studies have focused on the effects of critical temperature (CT) alterations during the spawning period, and largely ignored the effects of accumulated temperature (AT) alterations on gonadal development. Successful spawning r...

Eliminating tetracycline antibiotics from waste streams by conventional water treatment techniques remains challenging. Vacuum-ultraviolet/ultraviolet (VUV/UV)-based advanced oxidation technique is a promising, environment-friendly alternative to remove micropollutants from wastewater without adding chemicals. This study carried out flow-through ex...

To study the hyporheic exchange driven by a single peak flood‐induced water level fluctuation (i.e., flood wave), a method combining numerical simulation with theoretical derivation was proposed based on the Inbuk Stream, Korea, where flooding occurs frequently. The hyporheic exchanges induced by different flood waves were investigated by varying a...

The widespread occurrence of antibiotic resistance genes (ARGs) throughout aquatic environments has raised global concerns for public health, but understanding of the emergence and propagation of ARGs in diverse environmental media remains limited. This study investigated the occurrence and spatio-temporal patterns of six classes of ARGs in cyanoba...

Spatial downscaling is an effective way to obtain precipitation with sufficient spatial details. The performance of downscaling is typically determined by the empirical statistical relationships between precipitation and the used auxiliary variables. In this study, we conducted a comprehensive comparison of five empirical statistical methods for sp...

Sectional channelization of natural rivers for flood mitigation causes discontinuity of the riverine corridor, leading to unfavorable conditions for fish movement in the longitudinal direction. To minimize the negative effects, hydraulic structures (e.g. deflectors) are proposed as potential restoration measures in concrete flood channels. In this...

Several management strategies, such as wastewater treatment plants (WWTPs), have been increasingly used to mitigate nutrient pollution at watershed scale during the past few years. However, their cost-efficiency in controlling nutrient load is still debatable. This study quantified the annual cost of WWTP and constructed wetland based on process-ba...

For ecological restoration of concrete flood channels, installing current deflectors is a straightforward, cost-effective, and efficient approach with minimal maintenance. It is important to find the appropriate arrangement, orientation, number, protrusion length, width, and spacing of deflectors to achieve an effective flow pattern. In this resear...

Discharge from high dam causes total dissolved gas (TDG) supersaturation, which dissipates slowly along the downstream river and induces fish bubble disease. The dissipation process is closely related to the hydraulic condition. In most TDG prediction models, the hydraulic condition is lumped in a parameter called the dissipation coefficient (k), w...

Conservation of endangered or economic fish and control of invasive fish is a great challenge of hydraulic engineering worldwide. Flow velocity has been recognized to affect the spawning of fishes delivering drifting eggs in rivers. However, solid scientific supports and associated mechanisms to establish quantitative relations between flow velocit...

Stream biophysical processes are commonly studied using multidimensional numerical modeling that quantifies flow hydraulics from which parameters such as habitat suitability, stream carrying capacity, and bed mobility are derived. These analyses would benefit from accurate high‐resolution stream bathymetries spanning tens of kilometers of channel,...

Harmful algal blooms (HABs) can have dire repercussions on aquatic wildlife and human health, and may negatively affect recreational uses, aesthetics, taste, and odor in drinking water. The factors that influence the occurrence and magnitude of harmful algal blooms and toxin production vary in space and time and remain poorly understood. It is with...

The reliable immobilization of nuclear waste, particularly high-level waste (HLW), is a key issue for sustainable utilization of nuclear energy. Annealing process is adopted in nuclear waste vitrification to improve mechanical properties of products; however, its efficacy on chemical stability of treated HLW glass remain uncertain. This study aims...

Eutrophication has become one of the major environmental issues of global concern due to the adverse effects on water quality, public health and ecosystem sustainability. Fundamental research on the restoration of eutrophic freshwaters, i.e., lakes and rivers, is crucial to support further evidence-based practical implementations. This Special Issu...

Precipitation in arid mountainous areas is characterized by low rainfall intensity and large spatial heterogeneity, which challenges satellite-based monitoring by the space-borne sensors. This study aims to comparatively evaluate the detection ability of spatiotemporal patterns and extremes of rainfall by a range of mainstream satellite precipitati...

Hydropower development is the key strategy in many developing countries for energy supply, climate change mitigation, and economic development. However, it is commonly assumed that river dams retain nutrients and therefore reduce downstream primary productivity and fishery catches, compromising food security and causing transboundary disputes. Cont...

The increased use of hydropower is currently driving the greatest surge in global dam construction since the mid-20th century, meaning that most major rivers on Earth are now dammed. Dams impede the flow of essential nutrients, including carbon, phosphorus, nitrogen and silicon, along river networks, leading to enhanced nutrient transformation and...

Nitrous oxide is a powerful greenhouse gas, and its emissions from single reservoirs have been extensively studied; however, it still remains unclear about nitrous oxide emission patterns in cascade reservoirs. In this study, nitrous oxide emissions from cascade hydropower reservoirs were investigated using the thin boundary layer model in the heav...

Maintenance of ecological flow regime for aquatic biota is essential to river ecosystem health. To estimate ecological flow, habitat simulation methods have been widely applied because of their combination of hydrological regime and species hydraulic preference. However, few methods are available to provide a flow regime that varies over time due t...

Alien plant invasion has caused severe ecological problems in many places around the world. The introduction of exotic species may significantly alter the community composition and has a potential to change water cycle in the local ecosystem. Hydrocotyle vulgaris L. (H. vulgaris) is an introduced species, widely spreading in both aquatic and terres...

Improving the resilience of water distribution systems (WDSs) to handle natural disasters (e.g., earthquakes) is a critical step toward sustainable urban water management. This requires the water utility to be able to respond quickly to such disaster events, and in an organized manner, to prioritize the use of available resources to restore service...

By using a 2D-coupled flow and solute transport and reaction model across the stream-to-riparian continuum, this paper systematically studied the nitrogen-cycling processes driven by a flood wave and their spatial-temporal distributions. The influences on hyporheic nitrogen removal of different waves that vary by amplitude (A), duration (T), wave-t...

It is commonly assumed that dams retain nutrients and cause eutrophication in reservoirs after impoundment. In this study, we explored denitrification in a riparian zone at the land–water interface in a hydropower reservoir of the upper Mekong River. Results demonstrated that hydropower production intensified water level fluctuations in the reservo...

The occurrence and spatio-temporal patterns of five tetracyclines (TCs) and six of their degradation products were investigated in twenty-eight drinking water sources along the lower Yangtze River (LYR) over dry, normal and flood seasons. Tetracycline (TC), oxytetracycline (OTC) and doxytetracycline (DXC) were the dominant antibiotics detected with...

The biotoxicity of heavy metals in sediments toward benthic organisms has evoked great concern for the health of freshwater ecosystems. This study applied a sediment toxicity testing protocol to investigate the single and joint toxicity of cadmium (Cd) and lead (Pb) on Bellamya aeruginosa. B. aeruginosa were exposed to different concentrations of C...