Small Watercourses Research Articles

An Analysis of Hydromorphological Index for Rivers (HIR) Model Components, Based on a Hydromorphological Assessment of Watercourses in the Central European Plain

Assessing the hydromorphological conditions of watercourses is a requirement of the Water Framework Directive (WFD) and national river status monitors (e.g., in Poland,the State Environmental Monitoring, and Water Monitoring coordinated by Chief Inspectorate of Environmental Protection). This paper evaluates the hydromorphological status of 10 watercourses (30 measurement sections) in Poland based on the multimetric Hydromorphological Index for Rivers (HIR). A new approach to the delineation of the river valley (small watercourses) is proposed. An analysis of the influence of river valley management on the value of HIR and its components was carried out using statistical methods (basic statistics, Mann–Whitney U Test and Ward’s cluster analysis). In addition, the relationship between the components of the HDS (Hydromorphological Diversity Score) and HMS (Hydromorphological Modification Score) was analyzed (Spearman’s Rank Correlation Coefficient). HIR values for the watercourse sections ranged from 0.553 to 0.825. HDS values ranged from 27.5 to 75.5 and HMS from 2.0 to 17.5. The results of the basic statistical analyses showed slight differences between the two river valley delineation methods. The Mann–Whitney U Test showed a significant difference in the test significance level of the HDS, HMS and HIR for the river valley delineation methods. Spearman’s rank correlation analysis showed that most of the HDS and HMS parameters components had a low degree of correlation. The juxtaposition of the two methods for delineating a river valley and its influence on the HIR allows for a better understanding of the interdependence between its parameters.

Some Potentially Toxic Elements (Pb, Zn, As, Cd, Cu, Ni, and Cr) in Overbank Sediments of Smaller Water Courses from the Drina River Basin (Republic of Serbia)

Some Potentially Toxic Elements (Pb, Zn, As, Cd, Cu, Ni, and Cr) in Overbank Sediments of Smaller Water Courses from the Drina River Basin (Republic of Serbia)

Метод оценки теоретических характеристик малых осевых гидротурбин

Energy supply to remote areas remains a technical and social challenge. Construction of transmission lines to provide electricity to such areas is expensive and not always possible. One of the promising areas in this area is local energy generation based on local resources, in particular small watercourses, using small hydroelectric power plants. Small hydroelectric power plants are small hydropower facilities that use the energy of small watercourses to generate electricity. They have a number of advantages over traditional energy sources, such as environmental friendliness, low operating costs and high efficiency. However, the widespread introduction of small hydroelectric power plants is hampered by the lack of mass production of small hydraulic turbines and difficulties in designing low-power plants. Designing hydraulic turbines is a complex task that requires solving the inverse problem of hydrodynamics and finding the optimal shape of the flow path. To simplify the design of hydraulic turbines in the modern world, specialized software is used using various methods, including flow analysis, energy loss and blade shape optimization. This article based on an analysis of existing methods for designing and using a mathematical model of a hydraulic turbine with simplified blades, proposes a method for designing and analyzing the theoretical characteristics of the resulting hydraulic turbine. In conclusion, taking into account the use of the methodology for designing a hydraulic turbine for given parameters, its assessment is given, as well as ways to possibly improve the accuracy of the results obtained. Possible areas of application of the outlined design methodology are indicated.

Modern Dynamics of the Northern Dvina Delta: A Study by Multitemporal Space Images

The long-term dynamics of the Northern Dvina delta was studied with the comparison of space images of 1977 and 2020. A map of delta dynamics, compiled by them, shows that the islands at the delta coastline keep increasing and join to the delta, channel islands in the main branches are increasing, and small watercourses in delta islands become narrower and disappear. However, this long-term tendency of the continuing increase in delta area is now accompanied by the processes of shore erosion in islands at delta coastline from the side of the Dvina Bay.

Taming the torrent: changes in flood protection at the Gürbe River (Switzerland) from the nineteenth century until today

This paper analyses the flood protection history of the Gürbe River (Switzerland), a 29-km-long tributary of the Aare River. The upper reach of the river has the character of a mountain torrent and an exceptionally difficult flooding situation. For centuries, riparian communities were only able to take small protective measures. In the mid-nineteenth century, the flood protection strategy changed: between 1855 and 1881, the Gürbe River was channelised and stabilised by a torrent control system. Although the situation improved, flood damage could not be prevented as intended. Therefore, dozens of consecutive projects were implemented—without interruption until today. This paper examines why small watercourses are useful case studies, which protection measures were taken at the Gürbe River, how they corresponded to the prevailing flood protection philosophy, whether they were linked to floods and how flood protection influenced land use. The Gürbe regulation, its consecutive projects and the connected drainages had far-reaching effects: They allowed an intensive agricultural use of the valley floor, the construction of roads, a railway, and new settlements. Consequently, the social and economic pressure on the hazard area increased steadily over the decades. It created a vicious circle: the more that protective structures were built, the more important and profitable flood prevention became, and the more structures were raised. A reevaluation finally took place in the late twentieth century, based on increasing environmental awareness, and fostered by a catastrophic flood. However, the implementation of new projects proved to be difficult due to conflicting interests.

Bottom Sediments as an Indicator of the Geoecological State of Natural Water Currents

The parameters of the natural geochemical background of ecosystems of the Lunnoye deposit area were studied and the geoecological conditions of large and small watercourses of the Yukhukhta — Yukungra interfluve were assessed according to the state of the total pollution index of bottom sediments. 27 elements of the gross content were determined by the method of emission spectral analysis. The elements that determine the geochemical specificity of the territory were revealed: Bi, Li, Sn, Y, Be, Sc, K, Th, Cs and Ra. At the time of research, the state of the surface watercourses of the territory is assessed as moderately polluted. With further monitoring, special attention should be paid to the state of the river basin Yukhukhta and especially the dynamics of changes in the chemical composition of bottom sediments of the brook. Lunny and Mramorny. The elements K, Th, Cs, Ra, Be, Zn, Pb, As, Cr, and Ni are proposed as parameters for monitoring the geoecological state of bottom sediments.

Capacity of River Valleys to Retain Nutrients from Surface Runoff in Urban and Rural Areas (Southern Poland)

Studies on water quality are necessary, as catchments of small watercourses are exposed to anthropogenic influences associated with agricultural activities, settlement, transport and other undertakings, leading to water pollution. There has been insufficient research performed on the valley’s ability to retain nutrients during floods, contributing to water accumulation. The main object of the study was to identify the retention capacity of river valleys under various aspects of human urbanization. To represent soil water retention, the Soil Conservation Service Curve Number (SCS-CN) method was used. Spatiotemporal autoregressive models were exploited to investigate the relationship between pollutants in precipitation and surface water in rivers. In contrast, multivariate analysis was used to identify and reveal patterns of land use for specific chemical compounds in the headwaters. The canonical-correlation analysis (CCA) showed that Mg+2 and Ca+2 cations in rainwater and surface waters play the main roles in the geochemical cycle in urban and rural areas. In the urban catchment area, the strongest relations were found for NO3−, K+ and Na+. The average NO3− concentration in urban headwater was 8.3 mg·dm−3, the highest in the study area. The relationship between NO3− concentration in headwater and rainwater was found for all study catchments using spatial autoregression (SAR). High concentrations of SO42− in surface water have been identified in urban areas. Severe water erosion raises the risk of nutrient leaching in soils prone to surface runoff. As a consequence of low soil permeability and urbanization, retention capacity is significantly reduced in areas with low soil permeability. Land development plans should take spatial retention capacity into consideration. To ensure that large reservoirs can retain water in the face of climate change, riparian buffer zones (protective zones in valleys for small water bodies as well as Nature-based Solution) are important.

HYDROLOGICAL SERIES OF SMALL RIVERS IN THE SLAVSK DISTRICT OF THE KALININGRAD REGION

The article presents the results of hydrological calculations for small watercourses located in the Slavsk district of the Kaliningrad region. This territory is of considerable interest, as it contains the largest array of polder lands in the region. At certain periods, systematic observations of the hydrological characteristics of some water bodies were carried out on the studied territory: Zlaya river - Krasnoznamenskoye village, Osa river - Priozerye village, Nemoninka river - Timiryazevo village; currently there is only one hydrological post. In this work, taking into account the requirements of regulatory documents, the choice of analogous rivers is justified: for Zlaya river - Instruch river, for Osa and Nemoninka rivers - Zlaya River. According to the data of hydrological observations and the restored values, theoretical probability curves of average annual discharge of the studied rivers are constructed and the values of average annual discharge of various probability are determined. The data obtained can be used in the performance of engineering surveys, the development of measures aimed at the sustainable functioning of water management systems, the determination of ecological runoff.

Axial Flux Permanent Magnet Synchronous Generators for Pico Hydropower Application: A Parametrical Study

A pico hydropower plant is an energy harvesting system that allows energy production using the power of the water flowing in small watercourses, and in water distribution network. Axial Flow Flux Permanent Magnet Synchronous Generator (AFPMSG) are particularly suitable for this application, being efficient machines that achieve high power with small dimensions. This paper presents a parametrical study of several configurations and topologies of three-phase and single-phase AFPMSG, for pico hydropower application, to assess the most suitable dimensional characteristics for the most energy production using a safe voltage of 25 V. The AFPMSGs here considered has a simple single stator and rotor configuration, commercial-type permanent magnets, and concentric windings, to facilitate their cost-effective construction and the spread of their use also in developing countries. For each AFPMSG considered, the power output was calculated using 3-D modelling and Finite Element Analysis; besides, the different parameters and features that affect the power output were evaluated at different rotational speeds. The results achieving a power density up to 100 W/cm3, at 1000 rpm with energy produced to 1.7 kWh/day.

Fish Diversity and Abundance Patterns in Small Watercourses of the Central European Plain Ecoregion in Relation to Environmental Factors

Because of their size, small depth, periodic drying out, and often lack of buffer zone, small watercourses are especially sensitive to environmental changes, anthropopressure, and biodegradation which makes them extremely prone to decline in biodiversity. Small watercourses can harbor many species of fish, including alien and invasive species. The objectives of this study were the assessment of environmental conditions, the determination of the number of fish species, their density and diversity in 10 small water courses of the European ecoregion ‘Central Plains’, and to estimate the effect of individual habitat parameters on the ichthyofauna. The total number of fish caught during the study was 9339, representing 33 species. Statistical analyses showed that the density of rheophilous fish was under the effect of flow velocity, discharge, width, depth, oxygen content, and pH; for the limnophilous species, the decisive factors were: discharge, depth, width, and P-PO4. The density of the euryoecious species was affected by depth, pH, electric conductivity (EC), oxygen, as well as N-NO3. All the species were significantly influenced by sandy substratum and the development of aquatic vegetation. Each guild, and even individual species, had their preferred habitat conditions, which is important for water management, renaturisation, and restitution.

Monitoring Duckweeds (Lemna minor) in Small Rivers Using Sentinel-2 Satellite Imagery: Application of Vegetation and Water Indices to the Lis River (Portugal)

Duckweed species, particularly Lemna minor, are widely found in freshwaters all over the world. This macrophyte provides multiple ecosystems’ functions and services, but its excessive proliferation can have negative environmental impacts (including ecological and socio-economic impacts). This work explores the use of remote sensing tools for mapping the dynamics of Lemna minor in open watercourses, which could contribute to identifying suitable monitoring programs and integrated management practices. The study focuses on a selected section of the Lis River (Portugal), a small river that is often affected by water pollution. The study approach uses spatiotemporal multispectral data from the Sentinel-2 satellite and from 2021 and investigates the potential of remote sensing-based vegetation and water indices (Normalized Difference Vegetation Index (NDVI), Green Normalized Difference Vegetation Index (GNDVI), Normalized Difference Aquatic Vegetation Index (NDAVI), Green Red Vegetation Index (GRVI), Normalized Difference Water Index (NDWI)) for detecting duckweeds’ infestation and its severity. The NDAVI was identified as the vegetation index (VI) that better depicted the presence of duckweeds in the surface of the water course; however, results obtained for the other VIs are also encouraging, with NDVI showing a response that is very similar to NDAVI. Results are promising regarding the ability of remote sensing products to provide insight into the behavior of Lemna minor and to identify problematic sections along small watercourses.

The impact of urbanization and domestic waste on a small watercourse in the eastern Amazon basin

The present study shows the physical and chemical parameters collected in an urban river in the Eastern Amazon, they present the characteristics of the waters in the Neblina stream, which has its basin inserted in an urban center, in the city of Araguaína - TO. Therefore, the present study aims to investigate the water quality parameters of that stream, and thus allow deductions about the causes and effects of these changes. In this stream, sampling points were listed that contemplate environments from the springs to its mouth. Being, the quality of its waters, evaluated in two stages that envision two seasons (dry and rainy), respectively, August 2020 and March 2021. Adding a total of six sampling points, systematically visited in both seasons described, making up 12 samples, for all parameters analyzed here. In this way, the samples were explored in order to find values for the parameters: In Situ (Turbidity by turbidimeter; Dissolved oxygen; Electrical conductivity; Water temperature; Air temperature; pH); and Ex Situ (BOD; COD; Nitrogen series; Phosphate series; Fecal coliforms; Chlorophyll-α; Heavy metals). The parameters showed similar variations between the sampling points, with a notable data discrepancy between the mouth and head of the Neblina stream. These results show that there are higher concentrations for these parameters, directly related to the length of the route in the urban environment. Indicating a possible impact on the existing fauna and flora, which may conjecture a plausible toxicity and risks to organisms, as an admissible threat to biodiversity.

Mapping small watercourses with deep learning – impact of training watercourse types separately

Abstract. Deep learning methods for semantic segmentation have shown great potential in automating mapping of geospatial features, including small watercourses such as streams and ditches. There are a variety of small watercourse types. In many use cases users are only interested in specific types of watercourses. However, the impact on results from neural networks trained with only some types of small watercourses, compared to all types of watercourses is not well known. We trained four deep learning models to semantically segment watercourses from an elevation model. One model was trained with all small watercourses in the labels as a single class, while three models were trained each with a single type of watercourse in the label data. The results show that training the network with a single type of watercourse results in worse recall for all three watercourse types, compared to when training all of them together. This indicates that if the goal is to get as complete set of features as possible, it is better to include all watercourse types in the training data. Future studies could use multi-class output from neural network to determine how well networks could automatically classify features when training with all small watercourses in an area.

Survival analysis of African catfish and Nile tilapia briefly exposed to complex pesticide mixtures

BackgroundPulse exposures are the consequences of the intermittent release of pollutants in the environment. Brief exposure of aquatic organisms to high concentrations of pesticides simultaneously occurs, particularly in small watercourses during high flows. The effects of pulse exposure often include effects occurring during and after the exposure. Despite this, routine toxicity tests procedures often ignore brief exposure scenarios and the role of time in toxicity. We conducted a pulse toxicity test by briefly exposing African catfish and Nile tilapia fingerlings to pesticide mixtures of atrazine, mancozeb, chlorpyrifos, and lambda-cyhalothrin. The study aimed to estimate pesticide mixture interaction in pulse-exposed fish and elucidate the influence of species differences on the response of fish to the pesticide mixture.ResultsDespite the similarity in fingerlings weight, African catfish had a significantly higher survival probability than Nile tilapia after exposure to atrazine-mancozeb mixture. However, the survival probability of African catfish and Nile tilapia fingerlings were similar after exposure to atrazine-chlorpyrifos, atrazine-lambda cyhalothrin, mancozeb-chlorpyrifos, mancozeb-lambda cyhalothrin, chlorpyrifos-lambda cyhalothrin, and quaternary mixture (p > 0.05). The survival probability of exposed fingerlings was significantly lower for continuous than pulse exposure to the mixtures (p < 0.01). Nevertheless, the survival probability of 60 min of pulse exposure to 13.49 mg/L mancozeb-lambda cyhalothrin was similar to continuous exposure for 96 h. Atrazine-mancozeb, atrazine-chlorpyrifos, atrazine-lambda cyhalothrin, mancozeb-chlorpyrifos, mancozeb-lambda cyhalothrin, and the quaternary pesticide mixture were antagonists in African catfish but not in Nile tilapia. At the same time, chlorpyrifos-lambda-cyhalothrin was antagonistic in Nile tilapia but not African catfish.ConclusionsPesticide mixture interaction was antagonist but specie-dependent. Innate intrinsic and extrinsic deterministic factors and, to a limited extent, stochastic processes may have influenced the survival probability of African catfish, and Nile tilapia pulsed exposed to complex pesticide mixtures. Pulse toxicity assessment using survival analysis is relevant in ecotoxicology as it enables the study of factors that can influence pulse toxicity.

Characterisation of Benthic Macroinvertebrate Communities in Small Watercourses of the European Central Plains Ecoregion and the Effect of Different Environmental Factors.

Simple SummaryMacroinvertebrates are very important to aquatic ecosystems. They are food for vertebrates and their biodiversity serves as a testament of the quality of their habitats. The majority of research on macroinvertebrates simply describes the composition and population density of species living in large rivers and lakes. The aim of our study was to compare the biodiversity of macrozoobenthos assemblages and to determine the effect of physicochemical and hydrological conditions on their abundance and density in 10 small rivers in agricultural areas. Overall, 105 taxa were identified as species living in changing conditions. Oxygenation of water and nitrogen content were important factors determining the existence of macroinvertebrates in these rivers. Some groups of organisms showed sensitivity to changes in water temperature as well as to the flow and depth in rivers.Most publications on the influence of environmental factors on macroinvertebrate communities focus on large rivers, whereas relatively few examine small watercourses in agricultural areas, which, due to their size and pressure from intensive agricultural production, are much more susceptible to the effects of unfavourable environmental conditions or anthropopressure. The aim of our study was to compare the biodiversity of macrozoobenthos assemblages and to determine the effects of physicochemical and hydrological conditions on their abundance and density in 10 small rivers in agricultural areas located in northwest (53°23′ N 15°14′ E) and central (52°11′ N 20°48′ E) Poland. In total, 105 taxa were recorded, with the majority being euryoecious. Among the assessed physicochemical parameters, oxygenation was found to affect the density and number of taxa; another important factor was the content of nitrate nitrogen. Sensitivity to changes in water temperature was observed in some macrozoobenthos taxa (especially Decapoda). Of the examined hydrological parameters, the greatest effects were exerted by speed, flow, and depth.

Mini-Hydropower Plant Based on Lenyov Hydrobelt and Volume-Sectional Hydraulic Engine

The use of the energy of small watercourses with the help of small hydropower plants is one of the promising directions for the development of renewable energy. This article presents the designs of two different hydraulic engines, each of which has its own advantage. Therefore, the task of calculating the real parameters of the design of a mini-hydropower plant based on Lenyov hydrobelt has been solved. Theoretical calculations were validated numerically by the finite volume method and computational fluid dynamics modeling; both methods gave similar results. According to the results of calculations, this design based on the Lenyov hydrobelt with the capacity of 16 kW is advisable to place in a river with a flow velocity of at least 4.5 m/s. The article also presents an alternative type of developed mini-hydropower plant, -a volume-sectional hydraulic engine. The proposed rotary-type positive displacement hydraulic engine can operate at low pressure on a flat surface. The advantage of the hydraulic engine is the sectional operation of several working chambers. It was established that a high water velocity and a large volume of passing water was not required. The total force acting in the hydraulic engine is 5430.19 N. Due to the use of conical inlet channels, the water flow velocity was increased and the water flow became directional. The frequency of rotation of the hydraulic engine shaft at a river flow velocity of 4 m/s was 60.43 rpm. The received power in these modes was 22.25 kW.

Assessing the potential of Sentinel-2 data for tracking invasive water hyacinth in a river branch

Water hyacinth (Eichhornia crassipes) has become a threat to many aquatic environments worldwide. This aquatic weed presents a rapid reproductive capacity and outcompetes other aquatic plant species, forming dense, free-floating mats, which in many instances completely cover fresh-water surfaces. The infestation leads to several serious environmental (including ecological and socioeconomic) impacts that are hazardous to aquatic systems, disables human uses of surface waters, and affects hydraulic infrastructures (e.g., waterways and pumping stations). Our study explores the use of remote sensing tools to monitor and categorize the spread of water hyacinth, aiming at new insights into the detection, observation, and mapping of this invasive plant using vegetation indices and water indices calculated from multispectral data from satellite Sentinel-2, such as normalized difference vegetation index and normalized difference water index. The approach uses spatiotemporal information and has the potential to contribute to inform planners and decision-makers that are concerned with managing the plant by applying integrated measures. The case study deals with a small water course located in the downstream part of the Mondego river valley in Portugal, a country where water hyacinth is widely spread and constitutes a major problem, mainly in the irrigated agricultural areas of the Tagus, Sado, Mondego, and Lis rivers’ basins.

Assessment of the ecological state of small rivers of St. Petersburg according to the benthic macroinvertebrates indicators in 2019-2021

The work is devoted to the topical issue of assessing the state and changes of river ecosystems located within the boundaries of large cities and industrial agglomerations. The paper presents the results obtained during hydrobiological studies on small rivers of St. Petersburg (Russian Federation) in 2019-2021. The application of bioindication methods is substantiated in order to assess long-term changes in aquatic ecosystems under conditions of increasing anthropogenic load. Various characteristics of the community of benthic invertebrates are used as biological indicators of the state of hydroecosystems. Benthos samples were taken on eight small watercourses of the city, which are both tributaries of the Neva River of various orders (the Okhta, Slavyanka, Chernaya Rechka, Lubya, Okkervil, Volkovka rivers) and delta watercourses (the Smolenka and Karpovka rivers). The paper provides a brief description of the studied water bodies and sampling sites. A number of biotic metrics and biotic indices used for bioindication purposes both in Russia and abroad have been identified. It is noted that the unstable hydrochemical regime and low flow velocity in the small watercourses of the Neva River delta contribute to the intensification of the accumulation of sediments with high concentrations of ecotoxicants, which negatively affects both quantitative and qualitative characteristics of biocenoses. In some watercourses re is a complete absence of bottom invertebrates, which can be assessed as an ecological disaster. When assessing water quality by quantitative and qualitative characteristics of communities of benthic invertebrates (Mayer index, BMWP index, some biotic metrics), it can be concluded that Okkervil River, Chernaya Rechka River and Volkovka River should be attributed to watercourses whose ecological state is extremely unfavorable. The ecological state of the rivers Karpovka River, Slavyanka River, as well as the estuaries of Okhta River and Smolenka River should be considered unfavorable. And finally, the situation in Lubya River, the source of Smolenka River and in the middle reaches of the Okhta River can be considered close to satisfactory (low quality according to BMWP or moderately polluted water according to IM).

The Impact of Municipalities on Numbers and Diversity of Nontuberculous Mycobacteria in Small Watercourses of a Karstic Watershed

The Impact of Municipalities on Numbers and Diversity of Nontuberculous Mycobacteria in Small Watercourses of a Karstic Watershed

Assessment of uncontrolled runoff of biogenic substances from the Middle Ural small watercourses catchment territories involved into agriculture

Assessment of uncontrolled runoff of biogenic substances from the Middle Ural small watercourses catchment territories involved into agriculture