Hydromorphological Changes Research Articles

Investigation of hydromorphological changes of river corridor using satellite images

Investigation of hydromorphological changes of river corridor using satellite images

Long-term hydro-morphological changes in rivers: a case study

Long-term hydro-morphological changes in rivers: a case study

Combined effects of river hydromorphological disturbances on macroinvertebrate communities: Multispatial scales analysis of central European rivers

Hydro-morphological threats impact the natural physical characteristics of river ecosystems, such as flow regimes, sediment transport, and channel morphology. These negative effects can occur at multiple scales, ranging from local microhabitats to geographic regions. Understanding these interactions can be useful for an integrated conservation approach and is needed for effective freshwater management. The aim of the study was to elucidate the combined effects of hydro-morphological threats on macroinvertebrates at three spatial scales: macroscale, including whole catchments, mesoscale (hydro-morphological changes in individual river sections) and the microscale, describing the microhabitat conditions of European rivers. The diversity and trophic structure of 1120 local macroinvertebrate communities in 28 catchments of various hydro-morphological disturbance levels, ranging from 0 to 2400 m asl, were analyzed. The response of macroinvertebrates to the main disturbance gradient differed between mountain and lowland communities. Random forest analysis indicated that the most important predictor of the ecological, diversity, and trophic indices was described by flow rate reduction. Generalized additive mixed models showed that decreased flow combined with river incision explained most of the variation in macroinvertebrate indices. Our results emphasize that based on multi-spatial scale analysis, hydro-morphological threats are very important factors in invertebrates biodiversity loss. Thus, to implement effective river management, we should pay more attention to the combined effects of geomorphological threats.

INTERNAL AND EXTERNAL FACTORS OF USE AND CONSERVATION OF WATER RESOURCES IN ZHYTOMYR REGION

The water resources of Zhytomyr region are an important national asset, the condition of which affects people's health, economic development and the "good" environmental condition of the region. The current state of water resources in Zhytomyr region is of some concern due to a number of challenges, including: water pollution with organic materials, nutrients and toxic elements due to incomplete or no wastewater treatment, leaching of pollutants from agricultural land and plastic waste. The challenges also include limited access to quality drinking water in some regions, underdeveloped water supply and sanitation systems, unregulated water consumption and violations of water protection regulations, and hydromorphological changes related to hydropower and water flow regulation, including problems with coastal protection zones and water protection zones, as well as the effects of climate change, including floods and droughts.Taking this into consideration, conducting a SWOT analysis for the use and conservation of water resources in Zhytomyr region gets a particular relevance. The purpose of the study is to conduct a SWOT analysis that will not only allow a deeper analysis of the strengths and weaknesses of the regional water management system, but also to identify potential opportunities for improvement and risk reduction. The SWOT analysis will serve as the basis for developing strategies that will promote the conservation and rational use of water resources, strengthen the environmental well-being of the region, and ensure sustainable economic development and public health in Zhytomyr Region.

Impact and recovery of water quality in a river with salmon aquaculture

AbstractFreshwater aquaculture can have negative impacts on chemical, physical and biological water quality. To contextualise the impact that these activities may have, a case study site in Ireland was monitored for 1 year. The study aims were to investigate the impact of freshwater aquaculture on water quality (biological, physical, and chemical) and the degree of the impact and recovery in water quality, within 1000 m downstream of a salmon smolt hatchery. The hatchery was monitored, at four locations (upstream, 10, 100, and 1,000 m downstream of the discharge point). Data on macroinvertebrate, macrophyte, hydromorphology and chemical characteristics were collected. Results for the physical monitoring indicated no significant changes in hydromorphology between up and downstream sites. Chemical water quality did decrease downstream in terms of nitrogen (N) and phosphorus (P). The greatest concentrations in N and P were found at 1000 m though it is likely additional contributions from agriculture impacted this site. Dissolved oxygen was steady throughout the monitoring campaign with a 13% variance between upstream and downstream locations. Changes in biological indices were statistically significant for taxa at all downstream sites. There were positive trends which indicated a degree of recovery in biotic indices.

Evaluating Post-Fire Erosion and Flood Protection Techniques: A Narrative Review of Applications

Wildfires affect and change the burned sites’ condition, functionality, and ecosystem services. Altered hydrologic processes, such as runoff, increased streamflows, and sediment transport, are only a few examples resulting from burned soils, vegetation, and land cover. Such areas are flood-prone and face risks of extreme peak flows, reduced infiltration, water pollution affecting habitats, and hydromorphological changes. In this study, we present the different post-fire erosion and flood protection treatments that have been developed to avoid and mitigate the consequences and risks mentioned above. We categorize them into Land, Channel, Barrier, and Road treatments and analyze their types, such as cover-based methods, barriers, mulching, in-channel treatments, such as check dams, seeding, or even chemical treatments. Examples of how such treatments were used in real cases are provided, commenting on their results in flood and erosion protection. We found that cover changes were more effective than barriers, as they provided an immediate ground-cover increase in both Mediterranean and US sites. We explore the factors that play a role in their effectiveness, including storm duration and intensity, topography and slopes, land cover and uses, treatment implementation-installation, as well as fire-related factors such as burn severity. These factors have different effects on different treatments, so we further discuss the suitability of each one depending on the site’s and treatment’s characteristics. The outcomes of this work are expected to improve the understanding of the practical aspects of these treatments, providing for the first time a synthesis of the available knowledge on the multiple complex factors that can determine their efficiency.

Local Conservation of Nature Heritage as an Important Component in the Water-Energy-Food Nexus Approach. A Case Study of Srebarna Lake, Bulgaria

Conservation and sustainable use of natural resources are gaining more and more weight on the world political agenda and are attracting the attention of national governments at the highest level. The Water-Energy-Food (WEF) approach helps to understand the interrelationship between natural resources and human activities such as planning, managing, or consuming water, energy, or agricultural products. The world is currently facing the challenge of providing water, energy, and food for all. Scarce natural resources and the environment are increasingly being exploited, while at the same time the demand for fresh water, agricultural products, and energy increases. In this context, the protection of the quality of the available water resources becomes even more important. The preservation of the quality status of water resources is compromised by excessive exploitation, the introduction of polluting substances of different origins, hydromorphological changes in aquatic habitats, and climate changes. The main aim of this article is to clarify the Water-Energy-Food relationship and determine the current physico-chemical state of Lake Srebarna, which is a protected natural site in Bulgaria, a wetland of international importance, a biosphere reserve, and part of the list of world cultural heritage monuments and natural sights of UNESCO.

Influence of organic agricultural production on the condition of surface water

Agriculture and its methods of operation constantly influence the quality of water of surface water bodies. It was established in 2021 that in Lithuania, 63% of water bodies of the river and 64% of the lake categories are classified as risk water bodies and do not meet the good condition criteria. One of the main factors leading to the deterioration of the condition of surface water bodies is the continuing and increasing diffuse pollution, mainly from agricultural activities, together with pollution from agriculture; also, the condition in some water bodies deteriorates because of concentrated pollution, persistent effects of hydromorphological changes in surface water bodies, natural processes, and changing climatic conditions. This study aimed to determine the degree at which the ecological method of agricultural production affects the nearby surface water bodies. The obtained results show that the larger the area of organic farms from the entire area of the nutrient basin of a lake, the lower the values of biochemical oxygen consumption, total phosphorus, phosphate phosphorus, nitrate nitrogen, and total nitrogen concentrations. The ecological method of agricultural production has a positive effect on the condition of surface water bodies.

Effects of a nuclear power plant warmwater outflow on environmental conditions and fish assemblages in a very large river (the Danube, Hungary)

AbstractDirect or indirect effects of nuclear power plants' (NPPs) warmwater effluents on the structure of biotic assemblages are poorly known in very large rivers. We examined changes in physical habitat structure, temperature condition and their possible effects on the structure of Danubian fish assemblages due to the outflow of the Paks NPP's warmwater channel, in Hungary. Seasonal surveys conducted both upstream and downstream from the outfall showed that its hydromorphological effects were generally local and comparable to natural or other anthropogenic hydromorphological changes. The effect of the returned cooling water was more apparent in the seasonally recorded surface water temperatures and depended highly on the spatial positioning of the sampling sites. However, environmental and spatial variables accounted only for a low amount of variance in case of both shoreline and offshore fish assemblage data. Overall, we found that the outflow exerted only a local scale effect on the structure of Danubian fish assemblages. Rather, fish assemblages varied largely both inshore and offshore, which dynamics overruled any effects of the artificially elevated temperature. Our study highlights the importance of the assessment of hydrogeomorphological variability of rivers and their influence on fish assemblage variability when examining spatial effects of thermal pollution.

Monitoring of Dniester watershed pollution by reason of flooding and other environmental disasters

The work is about the solution of the scientific and practical task of substantiating the construction of geomodels of zones of probable flooding of the Dniester River on the basis of aerospace and contact measurements. In order to localize flooded areas and predict the dynamics of changes in geometric characteristics, natural and man-made factors that cause the rise of the groundwater level were analyzed. The main types of activity and load on the water resources of the Dniester basin are: residential and communal economy, industry, agriculture, including fisheries, hydropower and flood protection. Among the main cross-border problems typical for the Dniester River are: pollution by organic, biogenic and dangerous substances; hydromorphological changes; pollution by plastic and other household waste of the coastal strip of the river; spread of invasive species. The transboundary Dniester river is used for electricity generation. Dubossar hydroelectric power plant (HPP) (1954) in Moldova and Dnistrovsk HPP (1987) and Dnistrovsk HPP-2 (2000) in Ukraine were built on the river. Their activities led to hydromorphological changes of the river and its regulation.The main role in the pollution of the waters of the Dniester basin by biogenic substances on the territory of Ukraine and Moldova belongs to diffuse sources of agricultural origin. Water management activities and intensive chemicalization of agricultural land significantly affect the water quality of the Dniester River. The possibility of using available satellite images makes it possible to reduce the time and material costs of conducting additional contact measurements when determining zones of probable flooding, without reducing the accuracy of forecast parameters. The developed cartographic geomodels of areas of probable flooding make it possible to determine and visually assess the degree of flooding under different modes of operation of pressure horizons that have a hydraulic connection with groundwater.

A review of active and passive optical methods in hydrography

The history of using optical methods for hydrographic applications dates back to the mid of the last century. Since these early days, both passive and active techniques have evolved considerably and with ever new sensors and platforms available, there is unbroken scientific progress in this field capable of capturing the submerged topography of shallow water bodies. This review article gives an overview of the employed optical methods, which can be categorized into passive and active techniques. Passive methods comprise spectrally derived bathymetry as well as multimedia stereo photogrammetry, also referred to as photo bathymetry, and the active method is laser bathymetry. Another approach for categorizing optical methods is based on the used carrier platform, where satellites, crewed aircraft, uncrewed aerial systems and lately also remotely piloted underwater vehicles are used for mapping water bodies at different scales, resolution and accuracy. Another attempt to classify the approaches is whether the sensor is above or below the water table, referred to as through-water or underwater, respectively. Another focus of the paper is on data processing techniques including refraction correction, which is crucial for most optical hydrography approaches, signal processing of the radiometric content in spectrally derived bathymetry, and analysis of the backscattered waveform signal in laser bathymetry. In the recent past, machine learning techniques play an increasingly important role not only for object classification but also for regression-based depth estimation. And finally, the paper discusses the huge variety of applications ranging from mapping navigable channels for save ship navigation, disaster documentation, flood simulation, coastal protection, benthic habitat modeling, river restoration, monitoring of hydromorphological changes, maintenance of hydroelectric power plants, mapping of off-shore infrastructure, coral reef mapping to underwater archaeology. The paper presents seminal work in the field but also focuses on the multitude of recent scientific work demonstrating the unbroken relevance of optical hydrography.

On predicting of some consequences of planned dam construction in a pristine sand-gravel river large catchment: Rio San Pedro, Nayarit, Northwest Mexico

The pressure on water and energy resources is increasing globally, particularly in emerging countries. Some of them use their rivers for electric power generation, paying little or no attention to the hydromorphological changes generated in the rivers due to the infrastructure associated. One case is the St. Pedro River in the Northwest of Mexico (Rio San Pedro), where it is planned to build a hydroelectric dam. The importance is due to its flow discharges directly to a marsh system called Marismas Nacionales, considered a Biosphere Reserve that includes approximately 20% of all mangroves in Mexico. The alteration of its natural conditions is a critical issue for the ecosystem. There are many studies about the effects of dams on rivers after their construction, but only a few related to the river characterization before intervention within its channel. In this work, we highlight the relevance of the latter. We conducted extensive fieldwork, including morphological survey, sediment transport measurement, hydrodynamics, and bathymetry over 80 km of the river. We establish a baseline with the hydromorphological parameters in the river and run a numerical simulation with 2-D HEC-RAS 6.1 model to compare natural and controlled runoff. The goal of our study was to discuss possible scenarios and some consequences that could be generated with the dam construction—alterations in the lower basin— and suggest actions that can help to minimize the detrimental consequences. The novelty of our work is the scope of fieldwork, the wide range of the data, careful modeling based on detailed field data, and finally, the possible way one might use our results in the future to minimize the adverse consequences of dam construction. The methodology presented can be used as a guide to other dam projects worldwide, which face all these issues and need to redesign the dam and consider modern techniques to preserve the riverine conditions close to the more natural possible.

Taxonomic and Functional Metrics of Ciliates and Amoeboid Protists in Response to Stream Revitalization

Tufa-depositing streams provide great microhabitat complexity and are therefore inhabited by various periphytic phagotrophic organisms such as ciliates and amoeboid protists. Recent removal of invasive plant species Ailanthus altissima (Mill.) Swinge from the Skradinski buk tufa barrier (Krka National Park, Croatia) resulted in changes in the barrier hydromorphology including the reactivation (revitalization) of dry streams. The objective of this study was to investigate: (1) the taxonomic and functional response of periphytic ciliates and amoeboid protists to stream revitalization by comparing taxonomic (i.e., abundance, species richness and diversity) and functional (i.e., functional diversity) metrics between revitalized (N) and control sites (C) during 1 and 2-months immersion period; (2) which environmental and (3) periphyton-associated factors shape the taxonomic and functional metrics and to what extent; (4) how duration of immersion affects taxonomic and functional metrics at revitalized sites. Our results showed that taxonomic and functional metrics of ciliates and amoeboid protists responded to the prevailing conditions characteristic of revitalized tufa-depositing streams: changing hydrology (occasional high flow or drought), soil drainage, and extensive inorganic matter, i.e., tufa deposition, although their responses were somewhat different. The two assemblages also showed different responses of taxonomic and functional metrics with respect to immersion duration: while the taxonomic and functional diversity of ciliates at N sites increased with longer immersion, indicating niche diversification, those of amoeboid protists hardly changed with time. Our results suggest that a comprehensive analysis of taxonomic and functional metrics of ciliates and amoeboid protists could be a good proxy for assessing revitalization of tufa-depositing streams. However, the temporal component should always be considered when conducting such studies, as the colonization processes of ciliates and amoeboid protists are quite complex, especially in tufa-depositing streams.

A Study on Hydro-Morphological Changes and Water Quality Degradation in Buriganga River

A Study on Hydro-Morphological Changes and Water Quality Degradation in Buriganga River

Effects of recreational use on restored urban floodplain vegetation in urban areas

Urban river restorations focus on restoring aquatic and riparian habitats, increasing flood protection, and enhancing recreational potential. The increased recreational value such newly created urban green spaces is a key benefit of these measures as urban riparian areas are highly valued for recreation. However, high recreational pressure may contribute to the loss of natural vegetation and of biodiversity in restored riparian sites. This study investigates the impact of different recreational intensities and use types on the vegetation structure and vegetation quality by documenting direct (foot-traffic, breaking of branches, stems and roots) and indirect damages (litter and excrements). The major results are fourfold. First, while the proportion of some vegetation types can be correlated to the recreational intensity, neither recreation intensity nor recreation types enhanced the colonization success of invasive species. However, monitoring data showed that human-induced disturbances such as hydro-morphological changes favor alien plant establishment. Second, the study suggests a tipping point for pioneer vegetation at around a density of one user per 10 m river stretch. Already at lower user densities, pressure from trampling can slow down vegetation development. Third, the results indicate that users prefer urban greening and gravel bar elements rather than natural vegetation. Finally, while intensity of direct damages on the vegetation are weakly correlated with the user density, indirect damages increase with the user density. This study concluded that the identification of user hotspots would be helpful in developing a resilient restoration design, which in addition to information about the sensitive vegetation types in relation to recreational users and nature friendly recreational behavior could decrease vegetation damages. In particular, younger recreational users should be targeted by environmental protection campaigns.

Recent trends in inland water level change in coastal Bangladesh–implications of sea level rise in low-lying deltas

Accurately constraining local variation in tidal water levels is the vital first step in managing the risk of coastal hazards associated with sea level rise (SLR). Here we show sub-regional patterns in delta tidal dynamics and coastal SLR along the northern Bay of Bengal based on long-term (1990 to 2017) in-situ measurement data. Seasonal trend decomposition combined with robust linear modelling are applied to determine rates of water level change, with an average rise in coastal extreme sea levels of 6.9 ± 2.1 mm yr−1 translating to increases of 5.1 ± 4.2 mm yr−1 in tidal water levels within the delta. Mean increases of 18.3 ± 4.1 mm yr−1 and 18.2 ± 6.8 mm yr−1 at high and low-tide respectively in tidally dominated rivers of southwest Bangladesh contrast with the fluvially active central and eastern sections of the delta where falling trends of −6.5 ± 2.3 mm yr−1 (high-tide) and −10.2 ± 3.1 mm yr−1 (low-tide) are recorded. Rapid changes in river level at individual sites can occur over periods of ca. 3 to 10 years, most likely resulting from short-term hydro-morphological changes. An acceleration of change in high-tides is indicated by a rise from the long term (1950 to 2018) rate of 4.4 ± 1.5 mm yr−1 to 5.9 ± 3.2 mm yr−1 between 1990 and 2017, leading to increased risk for the local population. At local and regional scales, the inland impact of SLR within the delta is observed to be strongly modulated, necessitating more detailed analysis of driving mechanisms at the site specific level. Our results can be used to aid development of adaptation strategies in Bangladesh and as a call for increased monitoring of hydro-morphological parameters within the Bengal delta and other large deltas in Asia and worldwide.

Evaluating the hydromorphological condition of Tajan river using HMQI method

Over the last two decades, the need to restore rivers to the natural and near-natural state has become noticeable. One of the most important tools to achieve this goal is to assess the hydromorphological changes of the river due to human intervention. In the present study, in order to evaluate the hydromorphological conditions of the Tajan River along the middle to lower parts (city of Sari) the morphological quality index (MQI) and hydromorphological quality index (HMQI) has been used. Seven reaches in 50 m Riparian buffer width were selected and three quality main indicators including Geomorphological, artificial, and channel adjustment were studied using satellite images of Landsat 4 in 1975 and Landsat 8 in 2019, aerial photos in 1960 and 2006, hydrological data, and data collected during the field surveys. The results show that the studied reaches of Tajan River mainly classified as the moderate-quality class for the morphological quality index (MQI), while it is classified as one quality class lower for hydromorphological quality index (HMQI), mainly as the poor-quality class. The main reason is that all the studied reaches (except reaches 1 and 7), located downstream of the Shahid Rajaee dam, within the 30 km, which change considerably the river discharge and sediment transfer, also the extreme human impact and anthropogenic stresses in the catchment, such as land-use change. The results also showed that the method, which was used in this study, is effective, in general, index-based assessment, diagnosis of the hydromorphological problems, and an exact comprehensive realization of the response to the mentioned stresses.

Concept of an Innovative Autonomous Unmanned System for Bathymetric Monitoring of Shallow Waterbodies (INNOBAT System)

Bathymetry is a subset of hydrography, aimed at measuring the depth of waterbodies and waterways. Measurements are taken inter alia to detect natural obstacles or other navigational obstacles that endanger the safety of navigation, to examine the navigability conditions, anchorages, waterways and other commercial waterbodies, and to determine the parameters of the safe depth of waterbodies in the vicinity of ports, etc. Therefore, it is necessary to produce precise and reliable seabed maps, so that any hazards that may occur, particularly in shallow waterbodies, can be prevented, including the high dynamics of hydromorphological changes. This publication is aimed at developing a concept of an innovative autonomous unmanned system for bathymetric monitoring of shallow waterbodies. A bathymetric and topographic system will use autonomous unmanned aerial and surface vehicles to study the seabed relief in the littoral zone (even at depths of less than 1 m), in line with the requirements set out for the most stringent International Hydrographic Organization (IHO) order—exclusive. Unlike other existing solutions, the INNOBAT system will enable the coverage of the entire surveyed area with measurements, which will allow a comprehensive assessment of the hydrographic and navigation situation in the waterbody to be conducted.

Editorial: Green or red: Challenges for fish and freshwater biodiversity conservation related to hydropower

Editorial: Green or red: Challenges for fish and freshwater biodiversity conservation related to hydropower

Self-dynamics as a driver for restoration success in a lowland stream reach

Multiple stressors like alterations of water quality, hydrology and hydromorphology impact riverine ecosystems. To counteract its consequences, restoration measures are required, e.g. demanded by the EU Water Framework Directive. However, small-scale hydromorphological restoration measures often show little success. Besides overriding stressors, recolonization potential and insufficient time for development are often discussed as reasons for this lack of success. Over a period of 17 years a hydromorphological restoration measure in a German lowland stream reach was evaluated, excluding most of these confounding factors. The restoration measure was left to its self-dynamic development, i.e. there was no further intervention by water management, apart from some large wood installations after 8 years. In the accompanying studies, changes in hydromorphology and the organism groups macroinvertebrates (including both structural and functional diversities), fish and macrophytes were investigated.We proved a rapid and stable enhancement of ecological functions as indicated by a diverse and resilient macroinvertebrate biocoenosis. Both taxonomic and functional richness of macroinvertebrates significantly increased, but varied over time. Since the restoration measure allowed self-dynamic development, a taxonomic and functional endpoint was not achieved even after 17 years, even though near-reference conditions were attained after only 4 years. Deficits in fish communities were most probably due to their low recolonization potential.Our results underscore that small scale hydromorphological restoration can be successful if overriding stressors are absent. Furthermore, we proved the importance of self-dynamics in restoration measures, allowing hydromorphological and biological development.