Hydro-environmental Conditions Research Articles

On the performance of streamflow gauging using CCTV-integrated LSPIV in diverse hydro-environmental conditions.

Addressing the critical need for precise streamflow measurements in hydro-environmental research, this study evaluates large-scale particle image velocimetry (LSPIV) using cost-effective closed-circuit television (CCTV) cameras, providing a detailed sensitivity analysis in both laboratory and real-world canal settings. In laboratory conditions, a 45° camera angle notably enhanced performance, exhibiting a 12% decrease in MAE and a remarkable 40% reduction in RMSE compared to the performance of orthographic form. Tracer particles further enhanced LSPIV accuracy, decreasing both mean absolute error (MAE) and root mean square error (RMSE) by around 0.05 m/s. Optimal velocity coefficients for the lab ranged between 0.85 and 0.90. Nighttime measurements, using projection-based illumination, showed a minor 3% MAE variation and 0.02 RMSE difference versus daytime. In field experiments, a 45° upstream CCTV camera configuration notably improved LSPIV accuracy, achieving a 3% MAE and 0.055 m/s RMSE. For best results across different turbidity levels, we recommend a velocity coefficient range of 0.84 to 0.88. This study highlights the robustness and cost-efficiency of LSPIV as a transformative method for streamflow gauging, demonstrating its wide applicability in diverse hydro-environmental scenarios.

Flow and thermal regimes altered by a dam caused failure of fish recruitment in the upper Mekong River

Abstract Riverine fishes have been increasingly threatened by the global proliferation of both small dams and large hydropower projects to meet the soaring water, energy and food demands from growing human populations and urbanisation. However, empirical evidence of the direct effects on a specific species before and after dam construction and operation is rare. Causes of population decline vary among species and, although little known, they are of great importance for successful environmental flow regulation. We monitored the hydroenvironment and population dynamics of a Schizothoracinae fish (Schizothorax lissolabiatus) for 9 years before and after dam (i.e., Dahuaqiao) construction in the upper Mekong River to understand fish response processes and the underlying mechanisms. Optimal hydroenvironmental conditions for key reproduction stages (e.g., pre‐spawning, hatching and post‐hatching) were reconstructed using daily increment analysis of larval otoliths and hydroenvironmental data. The flow regime was substantially disrupted by the dam, and water temperature was only slightly changed. The disappearance of young of the year from downstream after dam operation indicates that the changed hydroenvironment caused recruitment failure in S. lissolabiatus. By matching optimal hydroenvironmental conditions for S. lissolabiatus reproduction with the monitored hydroenvironmental data series before and after dam operation, we found that changes in thermal regime alone caused narrowing of the reproduction window by an average of 41%, whereas flow‐regime change alone narrowed it by 96% and it was narrowed by 98% for thermal and flow changes combined. This study shows that the altered flow regime, but not the thermal regime, was the primary driver of the recruitment failure of S. lissolabiatus. The findings highlight the importance of prioritising flow‐regime management to improve recruitment success for S. lissolabiatus and to favour the persistence of other imperilled Schizothoracinae fishes and native species in dammed rivers.

A new chronology based on OSL and radiocarbon dating for the archaeological settlements of Vadnagar (western India) along with magnetic and isotopic imprints of cultural sediments

Vadnagar town of western India (North Gujarat) possess continuous human habitation record since ~2500 years. Owing to its rich cultural heritage, the town had been visited by Chinese pilgrims including Hiuen Tsang in 640 CE. Recent archaeological excavations at Vadnagar revealed continuous sequence of seven successive cultures from the Early historic (6th century BCE to 4th century BCE) period till present. From 2017 to 18 excavation seasons, ~18–20 m accumulation of cultural deposits were found at Ambaghat and Darbargarh localities. To complement and fortify the cultural chronology of these ancient cultural deposits, both conventional radiocarbon (C-14) and optically stimulated dating (OSL) methods were employed. Three C-14 and five OSL dates matched perfectly with the cultural ages of deposits and the entire cultural sequence spanned between 2nd century BCE to 6th century CE. Geochemical proxies (δ13C, δ 15N, C/N ratios) of excavated soil-sediments were measured to infer hydro-environmental conditions while soil magnetic parameters (χlf, χhf and χfd%) were measured to assess anthropogenic heating history. Average δ 13CTOC values of both trenches (−20.7 ± 3.5‰, −19.5 ± 3.5‰) indicated drier status of soil-sediments. Soil magnetic susceptibilities at lower and higher frequency ranges (χlf and χhf) varied in overlapping ranges i.e. 88.5 ± 43.1 and 121.4 ± 72.1 (10−8m3 kg−1) respectively, indicating the presence of super paramagnetic grains in the soil attributable to firing activities of soil-sediment. Average χfd% values (8.3 ± 1.1, 7.7 ± 2.0) indicate excavated soils undergone pedogenic processes.

Information–Modeling Complex for Assessing the Hydroenvironmental Conditions of Reservoirs

An Information–Modeling Complex has been developed for the information support of managerial decision making in the field of rational use, protection, and restoration of reservoir ecosystems. The system successively implements three mathematical hydroenvironmental models of the system Nizhnekamskoe Reservoir Drainage Basin―the Nizhnekamskoe Reservoir―the Kuibyshev Reservoir. The complex of models is an effective tool for studying the response of the ecological conditions of reservoirs to natural changes and anthropogenic impact. The use of the complex as a tool for environmental forecast or an expert system in scenario simulation of natural processes is the most promising way to solving the problems of water quality management and reservoir production.

Zoneamento Hidroambiental da Bacia Hidrográfica do Rio Acará, Amazônia Oriental

O zoneamento ambiental é um dos principais instrumentos de planejamento ambiental que contempla a análise integrada dos aspectos naturais e socioeconômicos, o qual permite identificar espacialmente as potencialidades e fragilidades dos sistemas ambientais. Nesse sentido, o presente trabalho teve como objetivo propor um zoneamento hidroambiental da bacia hidrográfica do rio Acará sob um viés sistêmico e integrado da paisagem a partir do conhecimento das suas fragilidades, a fim de identificar as áreas que potencializam a manutenção de água no sistema hidrográfico, com intuito de preservação e conservação dos recursos hídricos. A metodologia baseou-se na proposta de Ross para avaliar a fragilidade dos ambientes antropizados. Para isso, foram utilizados dados geocartográficos dos aspectos do meio físico e o padrão de uso e cobertura da terra com emprego da lógica Fuzzy para confeccionar as cartas de fragilidade hidropotencial e hidroambiental. Os resultados demonstram que o uso e cobertura da terra impactaram diretamente na manutenção de água no sistema hidrográfico da bacia, evidenciado através da conversão de classes com baixa fragilidade hidropotencial para classes com maior nível de fragilidade hidroambiental. Com o diagnóstico das condições hidroambientais da bacia do rio Acará, a proposta de zoneamento hidroambiental apresenta-se como um importante instrumento para os gestores no auxílio do processo de planejamento e reordenamento territorial.

Тізаноптерофауна інтродукованих рослин в умовах урбанізованих територій України

Проаналізовано флору дванадцяти обраних парків міста Києва. Визначено кількість видів інтродукованих рослин на обраних ділянках. Досліджено антропогенні фактори, що проявляються у процесі створення парків, ботанічних садів, бульварів тощо. З'ясовано, що для створення таких екосистем використовують як місцеві декоративні рослини, так і багато інтродукованих декоративних і плодових рослин з багатьох країн світу. Встановлено особливі характеристики цих екосистем, що характеризуються гідроедафічними умовами середовища. Розглянуто екологічну детермінованість заселення трипсами рослин в умовах урбанізованих територій. Встановлено фактори, що впливають на щільність популяції, ритм активності, фізіологічні умови розвитку трипсів. Вивчено фауну трипсів урбанізованих територій, яка представлена трьома родинами: родина Thripidae, родина Aeolothripidae та родина Phlaeothripidae. Фауна трипсів урбанізованої території налічує 121 вид. Наведено чисельність представників трипсів за родами. Рід Thrips є найчисельнішим за наявними представниками. Виявлені трипси урбанізованої території поділено за трофічними зв'язками за типом живлення на: поліфаги, олігофаги, монофаги та хижаки. Найбільше представників багатоїдних видів трипсів – поліфагів. Також трипси поділено за трофічними зв'язками з рослинами на чотири групи: трипси, що мешкають у суцвітті рослин; злакові угруповання трипсів; трипси, що мешкають на листі молодих пагонів рослин; трипси, що мешкають на листі молодих пагонів дерев і кущів. Встановлено, що найбільше представників трипсів, що мешкають у суцвітті рослин.

The hydro-environmental conditions and zooplankton of the light house creek, Lagos, Nigeria

The hydro-environmental characteristics and zooplankton diversity at the Light-house creek were investigated for six months. Variations in water quality parameters were linked with tidal sea water incursion and rainfall/floodwater dynamics. Water and air temperatures were high (>25.8⁰C; >28 ⁰C) and Transparency decreased in the wet months. Salinity values were high (>19 ‰) all through, while the water remained alkaline (≥6.68). Biochemical oxygen demand (4.0-18.0 mg/L), chemical oxygen demand (1.0 and 2.0 mg/L) phosphate (0.06 and 8.40 mg/L) and nitrate showed variations (0.80 mg/L). On the other hand, minimum sulphate value was 224.0 mg/L while silicate values ranged from 2.10 to 4.60 mg/L. Zinc (<0.047 mg/L), Iron (<0.28 mg/L) and copper values (<0.014 mg/L) also varied. The zooplankton spectrum comprised 62.36% Arthropoda, 0.78% Chordata, 0.71% Cnidaria, 35.9%, juvenile stages and 0.95% were from other groups. A total of 49 zooplankton taxa from five different phyla and 18 juvenile stages were identified. Zooplankton biomass in terms of individuals per ml was higher in the dry than wet months. The copepod nauplii, bivalve and zoea larvae were the dorminant juvenile forms. Species richness indices (d) and similarity index were higher in the dry months than the wet months. Key Words : Phytoplankton, juvenile stages, Lagos habour, lagoon, water chemistry, mangrove creek

ГІДРОХІМІЯ ТРАНСКОРДОННОЇ РІЧКИ ЗАХІДНИЙ БУГ НА ТЕРИТОРІЇ УКРАЇНИ

The purpose of the article is to study the hydrographic features of the transboundary Western Bug River basin in Ukraine, its hydrochemical regime and ion flow, as well as possible manifestations of anthropogenic influence on them. Methods. The methods of statistical processing of data of observation series, the method of calculating the ion flow were used. Results. The features of the hydrochemical regime and the ionic runoff of the transboundary river are estimated. Western Bug on the main ions in Ukraine. Especially noted anthropogenic influence r. Poltva, into which the wastewater of Lviv is dumped, on the quality of water of the Western Bug. Scientific novelty. The flow of chemicals with the waters of the Western Bug basin from the territory of Ukraine and Poland within the general part of the basin has been calculated. Practical significance. Noted the need to comply with hydro-environmental conditions on the river. Poltva, which introduces a significant portion of chemicals in the river. Western Bug and affects the quality of its waters.

Responses of the phytoplankton community in the Yangtze River estuary and adjacent sea areas to the impoundment of the Three Gorges Reservoir

The phytoplankton community in river estuaries is subject to complex physical and chemical stresses. The construction of the Three Gorges Dam (TGD) has dramatically changed the hydro-environmental conditions, including hydrological regimes and water quality in the Yangtze River estuary (YRE), which could have a significant impact on the estuarine ecosystem. To evaluate the effects of hydro-environmental alterations on the phytoplankton community in YRE, sampling campaigns were conducted in the area during 2010–2011; meanwhile, historical data before TGD construction and during the TGD filling period were collected. Seasonal variations showed that diatoms dominated the community throughout the sampling period, and the most important environmental factors affecting the phytoplankton community were silicate, total suspended solids and phosphate. With respect to differences in the three phases (before TGD construction, during TGD filling and after TGD filing), the abundance of phytoplankton showed an increasing trend: the proportions of diatom species numbers declined, while the proportions of Dinophyta species numbers increased. The position of phytoplankton abundance maximum moved inwards to the estuary of the Yangtze River after the impoundment of the TGD.

Zooplankton community in Yangtze River Estuary and adjacent sea areas after the impoundment of the Three Gorges Reservoir

Zooplankton is an important component of aquatic ecosystems and community variation reflects environmental changes. The impoundment of the Three Gorges Reservoir (TGR) has dramatically altered hydro-environmental conditions from hydrological regimes to water quality, which may have a serious impact on the estuarine ecosystem. This study analyzed the characteristics of the zooplankton community as well as their relationships to hydro-environmental factors in the Yangtze River Estuary (YRE) and the adjacent sea areas using the data after TGR impoundment. The historical zooplankton data over the past 30 years were also collected from the literature to explore long-term changes of the zooplankton community by the Mann–Kendall test. The results show that the dominant species were Noctiluca scintillans and Calanus sinicus in spring, Acartia pacifica in summer, and Paracalanus aculeatus in autumn. The most important environmental factors affecting the zooplankton community for the whole year were salinity and temperature of the bottom layer, which were largely influenced by river discharge and thus by reservoir regulation. Combined with the long-term historical data, the biomass and population density of zooplankton showed an increasing trend, and the community structure of zooplankton also shifted over the past 30 years.

Burrowing Criteria and Burrowing Mode Adjustment in Bivalves to Varying Geoenvironmental Conditions in Intertidal Flats and Beaches

The response of bivalves to their abiotic environment has been widely studied in relation to hydroenvironmental conditions, sediment types and sediment grain sizes. However, the possible role of varying geoenvironmental conditions in their habitats remains poorly understood. Here, we show that the hardness of the surficial intertidal sediments varies by a factor of 20–50 due to suction development and suction-induced void state changes in the essentially saturated states of intertidal flats and beaches. We investigated the response of two species of bivalves, Ruditapes philippinarum and Donax semigranosus, in the laboratory by simulating such prevailing geoenvironmental conditions in the field. The experimental results demonstrate that the bivalve responses depended strongly on the varying geoenvironmental conditions. Notably, both bivalves consistently shifted their burrowing modes, reducing the burrowing angle and burial depth, in response to increasing hardness, to compensate for the excessive energy required for burrowing, as explained by a proposed conceptual model. This burrowing mode adjustment was accompanied by two burrowing criteria below or above which the bivalves accomplished vertical burrowing or failed to burrow, respectively. The suitable and fatal conditions differed markedly with species and shell lengths. The acute sensitivities of the observed bivalve responses to geoenvironmental changes revealed two distinctive mechanisms accounting for the adult–juvenile spatial distributions of Ruditapes philippinarum and the behavioral adaptation to a rapidly changing geoenvironment of Donax semigranosus. The present results may provide a rational basis by which to understand the ensuing, and to predict future, bivalve responses to geoenvironmental changes in intertidal zones.

A contribution to the data on tench (Tinca tinca L., Cyprinidae, pisces) distribution in Serbia

The studies on the ichthyofauna of Serbia that have been conducted so far indicate the sporadic tench (Tinca tinca L.) presence in typical habitats. The hydroenvironmental conditions necessary for the survival of this fish species are highly variable and, generally, are more favourable in the northern part of the country (the Vojvodina Province). Although the tench presence has been registered at over 30 sites, there is a tendency of a decrease in population abundance. This is due to the reduction of the surface area of the macrophyte-covered flood zones induced by the damming and regulation of rivers, high water level fluctuations, and water amount reduction in the majority of watercourses, a massive increase in the number of allochthonous phytofagous species, reservoir sediment deposition, water quality deterioration and other factors. The tench conservation status in Serbia is officially designated as Low Risk - Least Concern. It may be transferred to a higher category if the tendency towards deterioration of survival conditions for the species should continue.

Dynamics of fluid circulation in coupled free and heterogeneous porous domains

Fluid flow in coupled free and porous domain, particularly when the porous medium is heterogeneous, is encountered in many hydro-environmental conditions, e.g., leakage from underground pipe, combined groundwater lake–subsurface interactions. One of the most difficult problems in the study of coupled flow behaviour has been the development of a universally applicable modelling scheme for combining the flow regimes. This is because the free/porous interfacial properties (e.g., shear-stress; velocity slip) that govern the coupled flow behaviour are difficult to determine experimentally under hydro-environmental conditions. On the other hand, the implications of various forms of heterogeneity in the porous media properties can be very different on the fluid-flow behaviour. Difficulties may also arise in direct coupling of the model equations that govern the fluid flow in the individual regions (e.g., Navier–Stokes for free-flow region and the Darcy's equation for the porous flow region). Consequently, models of coupled free and porous flow for hydro-environmental conditions are not very well developed at the moment. While there are some indications that fluids in coupled free and porous domains may circulate (i.e., development of flow cells), there is a lack of appropriate 3D analysis on how heterogeneities in porous media may affect such flow patterns. In this paper, we aim to analyse how porous media heterogeneity affects the dynamics of flow circulation in the porous side of a coupled free and porous domain. For this purpose, we analyse flow patterns in several model domains made up of two porous layers with differing permeabilities. The governing model equations are discretised and solved using the standard finite volume method on a staggered cell-centred mesh. The temporal discretisation is done using the explicit method. An in-house graphical user interface (GUI) has been created specifically to aid in the visualisation of otherwise complex flow patterns. The GUI contains many post-processing options and provides a comprehensive tool for the analysis of hydrodynamics and contaminant motion (not discussed in this paper) in coupled free and porous flow domains. This GUI is described in this paper briefly. The effects of altering the aspect ratio (i.e., multi-scale) of the domain on the coupled flow pattern have also been discussed.

Problem Cyanobacterial Blooms: Explanation and Simulation Modelling

Cyanobacteria (blue-green algae) have become an issue of increasing concern to water-resource managers in recent years. Cyanobacterial blooms form when a large population migrates to the lake surface. Vertical migration is controlled by the physiological response of the cyanobacteria to changes in hydro-environmental conditions. The mechanics of bloom formation are considered in detail. Additionally cyanobacteria move across a water-body by entrainment within turbulent currents. These processes can be modelled to aid bloom management and theoretical investigation. An example of such a model (SCUM) is presented. The role of modelling in management is considered and an alternative schematic model to calculate the cyanobacterial light-budget is presented. Such a model could form the basis of a light-limited growth model.