Hydrological Regime Of Rivers Research Articles

HYDROLOGICAL REGIME AND WATER RESOURCES OF RIVERS OF THE ZERAFSHAN BASIN UNDER CLIMATE CHANGE

The work assessed the impact of climate change on the hydrological regime - long-term fluctuations, intra-annual distributions, maximum flow rates and, in general, on the water resources of the rivers of the Zeravshan basin. Calculations to assess changes in meteorological parameters were performed for two climatic periods. Some changes in the regime of air temperature and precipitation were revealed. Their influence on the hydrological regime of rivers is assessed. Particular attention is paid to the issues of quantitative assessment of water resources of the rivers of the studied basin.

River Hydrological Regime Changes and Their Attribution: A Case Study in the Upper Reaches of the Yangtze River Using a Multi‐Model Approach

River Hydrological Regime Changes and Their Attribution: A Case Study in the Upper Reaches of the Yangtze River Using a Multi‐Model Approach

Index-Based Alteration of Long-Term River Flow Regimes Influenced by Land Use Change and Dam Regulation

The growing population and expansion of rural activities, along with changing climatic patterns and the need for water during drought periods, have led to a rise in the water demand worldwide. As a result, the construction of water storage structures such as dams has increased in recent years to meet the water needs. However, dam construction can bring significant alterations to the natural flow regime of rivers, and it is therefore essential to understand the potential effects of human structures on the hydrological regime of rivers to reduce their destructive impacts. This study analyzes the hydrological changes in the Shahrchai River in response to the Shahrchai Dam construction in Urmia, Iran. The study period was from 1950 to 2017 at the Urmia Band station. The Indicators of Hydrological Alteration (IHA) were used to analyze the hydrological changes before and after regulating, accounting for land use changes and climatic factors. The results revealed the adverse effects of the Shahrchai Dam on the hydrological indices. The analysis showed an increase in the average flow rate during the summer season and a decrease in other seasons. However, the combined effects of water transferring for drinking purposes, a decrease in permanent snow cover upstream of the dam, and an increase in water use for irrigation and agricultural purposes resulted in a decrease in the released river flow. Furthermore, the minimum and maximum daily flow rates decreased by approximately 85% and 65%, respectively, after the construction of the Shahrchai Dam. Additionally, the number of days with maximum flow rates increased from 117 days in the pre-dam period to 181 days in the post-dam period. As a concluding remark, the construction of the Shahrchai Dam, land use/cover changes, and a decrease in permanent snow cover had unfavorable effects on the hydrological regime of the river. Therefore, the hydrological indicators should be adjusted to an acceptable level compared to the natural state to preserve the river ecosystem. The findings of this study are expected to guide water resource managers in regulating the sustainable flow regime of permanent rivers.

Hydrological Regime of Rivers in the Periglacial Zone of the East European Plain in the Late MIS 2

At the end of the Pleniglacial and the first half of the Late Glacial period, approximately between 18 and 14 ka BP, rivers of the central and southern parts of the East European Plain had channels up to 10 times as large as the present day channels of the same rivers. These ancient channels, called large meandering palaeochannels, are widespread in river floodplains and low terraces. The hydrological regime of these large rivers is of great interest in terms of the palaeoclimatology of the late Marine Isotope Stage 2 (MIS 2). In this study, we aimed at quantitative estimation of maximum flood discharges of rivers in the Dnepr, Don and Volga basins in the late MIS 2. To approach this, we used massive measurements of the morphometric characteristics of large palaeochannels on topographic maps and remote sensing data—palaeochannel width, meander wavelength and their relationships with river flow parameters. The runoff depth of the maximum flood, which corresponds to the maximum depth of daily snow thaw during the snowmelt period, was obtained for unit basins with an area of <1000 km2. The mean value for the southern megaslope of the East European Plain was 44.2 mm/day (6 times the modern value), with 46 mm/day for the Volga River (5.5 times), 45 mm/day (6.3 times) for the Don River and 39 mm/day (8 times the modern value) for the Dnepr River basins. In general, the Dnepr basin was drier than the Don and Volga basins, which corresponds well to the modern distribution of humidity. At the same time, the westernmost part of the Dnepr River basin was relatively wet in the past, and the decrease in humidity from the past to the modern situation was greater there than in the eastern and central regions. The obtained results contradict the prevailing ideas, based mainly on climatic modeling and palynological data, that the climate of Europe was cold and dry during MIS 2. The reason is that palaeoclimatic reconstructions were made predominantly for the LGM epoch (23–20 ka BP). On the East European Plain, the interval 18–14 ka BP is rather poorly studied. Our results of paleoclimatological and palaeohydrological reconstructions showed that the Late Pleniglacial and the first half of the Late Glacial period was characterized by a dramatic increase in precipitation and river discharge relative to the present day.

Assessing the effects of dam regulation on multiscale variations in river hydrological regime and ecological responses

ABSTRACT Using a combination of the long short-term memory model and hydrological change indicators, this study proposes an assessment framework at inter-annual and intra-annual scales to quantify the hydrological regime changes and ecological event responses caused by the regulation of the Three Gorges Dam (TGD) in the upper reaches of the Yangtze River. The results indicate that during the post-TGD period (2004–2019), 2 indicators of the natural flow regime undergo a high degree of alteration at the inter-annual scale, which increase to 12 when regulated flows are considered. Furthermore, we find that while climate and incoming water change significantly reduces the annual flow and monthly flow during the flood season, it increases the complexity (79%) and ecodeficit at the seasonal scale (94%). Among the 32 indicators of hydrologic alteration, TGD is the dominant factor influencing changes in 20 indicators, increasing the magnitude of low-flow events, decreasing the frequency of high-flow pulses, and advancing the timing of 1-day minimum flow (43 Julian date). From the hydrological perspective, the altered rising water conditions due to TGD regulation may cause an average decrease of 19.5% in the fry abundance for the Four Famous Major Carps.

Reconstructing long-term natural flows by ensemble machine learning

Large-scale human activities have caused significant disruption to the natural flow regime of rivers worldwide, leading to substantial deviations from river flows’ natural state. The natural hydrological regime of rivers holds great significance for the conservation and management of riverine ecosystems, which relies on the accurate reconstruction of natural river flows. However, the application of existing high spatiotemporal resolution large-scale natural flow datasets at the regional scale has not been adequately assessed, thereby limiting their regional-scale utility. In this study, utilizing global reanalysis datasets and observation data, in combination with ensemble machine learning models, we constructed long-term natural flow time series for inflows into the Pearl River Delta and evaluated the performance of these reconstructed inflows based on observed flow records during undisturbed periods. The reconstruction shows that the ensemble model, the AutoGluon model, indicates the best performance when compared with other machine learning models and outperforms the existing publicly available large-scale datasets in terms of evaluation metrics for the corresponding natural flows. The results of Indicator of Hydrologic Alteration and Range of Variability Analysis (IHA-RVA) indicate that climate variability, reservoir regulation and human activities have significantly altered the natural flow regime of the Pearl River Delta. Specifically, human activities generally tend to smooth natural flow variability in the Pearl River Delta. This research is expected to provide an efficient and reliable method for reconstructing natural flows and offers guidance for water resource management and ecosystem conservation.

HYDROLOGICAL REGIME OF WATER STREAMS AND THE PROBLEMS OF PUBLIC WATER SUPPLY IN THE REPUBLIC OF KALMYKIA

The constant shortage of fresh water for drinking and municipal use in the Republic of Kalmykia has become critically acute recently. Both natural factors, i.e. increasing climate aridity, limited reserves of fresh surface and groundwater, lack of sufficiently long sections of large rivers with constant flow, and the deterioration of hydraulic structures are the reasons. The exploitation of groundwater in existing deposits has led to their depletion and deterioration, while large deposits of fresh and slightly brackish groundwater in the southern Caspian region cannot be used because the content of pollutants in them is rather high. Recovery of old and construction of new water pipelines from the Volga River requires permanent significant financial investments at the federal level. Therefore, recently a new way to increase the supply of fresh water suitable for drinking purposes, i.e. an artificial groundwater recharge (AGR), has been actively discussed. The article provides an actual assessment of water resources of the littlestudied surface runoff of the rivers of Kalmykia, considers the possibility and feasibility of creating infiltration basins to replenish groundwater reserves, and calculates the parameters and operating mode of five planned basins. The main source of fresh surface water in Kalmykia is the rivers of the Ergeni Upland. The average long-term flow from its eastern slope is estimated at 0,120 km3/year, from the western slope at 0,105 km3/year and from the southern slope at 0,045 km3/year. Trends in modern modification of the hydrological regime of rivers under the influence of climate change have been revealed, namely a decrease in annual runoff and its intra-annual redistribution with a reduction of spring floods, a slight increase in winter runoff and a leveling of summer low-water periods. Calculation of the operating mode of planned infiltration basins allowed us to draw the following conclusions: the maximum possible volume of total infiltration will be about 220 thousand m3/year, which is 36 times less than the presentday water intake from the Troitsk and Bayarninsky fields for public water supply; sufficiently efficient operation of pools is only possible with annual cleaning of accumulated silt deposits, otherwise the soil filtration coefficient will come down each year, resulting in the reduction of infiltration supply by dozens times. Thus, the AGR can only be a temporary measure to compensate for the subsidence of groundwater level until the reconstruction and construction of new water pipelines from the Volga River to supply the city of Elista and the surrounding area with drinking water of acceptable quality

Ecological features and resource status of carp fish in the lower Amu Darya River

This study presents the results of multi-year comprehensive scientific research conducted in the lower reaches of the Amu Darya River. The primary material for the study consisted of our own collections of ichthyological material of fish populations to determine their current status in fisheries. The research focused on various groups and statuses of carp fish. As a result of the study, the current composition of carp fish fauna in the lower reaches of the Amu Darya River, their ecological characteristics, and their commercial status in connection with the anthropogenic transformation of the river's hydrological regime were identified. Under these conditions, research is being conducted to create sustainable fish resources and their effective utilization, including the study of alternative water sources in the Southern Aral Sea region.

Водозаборное сооружение для целей орошения земель в горных условиях Северного Кавказа

Purpose: to develop a water intake structure for land reclamation purpose under the conditions of water withdrawal from mountainous natural water sources. Materials and methods. The paper is based on the theoretical analysis of the river hydrological and geological characteristics, which made it possible to calculate the minimum flow required for the stable operation of water intake structure and guaranteed water withdrawal during the growing seasons. The design parameters of the water intake structure were developed using the method of expert assessment with non-parametric statistics by comparing several dependent variables. Having determined the required qualities for a water intake structure, the design of a reclamation facility adapted for the conditions of the mountain and foothill zones of the North Caucasus was developed. Results. To achieve this goal, a static method for analyzing water intake structures was adapted, and statements with a factorial rating scale for expert assessment were developed. Kendall's concordance coefficient was 0.726, the data were consistent, the significance level P was less than 0.05, the differences between the factors were significant. The layer-by-layer latticed type of water intake structure has maximum efficiency. The design of a bottom-type water intake structure has been developed on the basis of the river hydrological regime and the method of water supply to the system. This type of structure demonstrates high efficiency in conditions of difficult terrain and unstable water source regimes during the growing seasons, ensuring stable water intake with minimal impact on the ecosystem. Conclusions. The proposed design of a water intake structure can be adapted to different types of water resources and their fluctuations, which makes it acceptable for mountainous areas with variable water levels in natural water sources. Minimal impact on the ecosystem is ensured by a high degree of water purification without significant changes in river channels.

Analysis of the suitable ecological flow of benthic animals in the lower reaches of Xiangjiaba Reservoir in the upper reaches of the Yangtze River based on the physical habitat model

Abundant water resources have facilitated the completion and operation of numerous large-scale water conservation projects. However, the operation of cascade hydropower stations has changed the natural hydrological regime of rivers, thereby affecting the integrity and stability of downstream benthic animal habitats. To quantitatively evaluate the impact of infrastructure development, we proposed a coupling of hydrodynamic and habitat models, with benthic animals as indicator species (because they are highly sensitive to hydrological changes). This study established a physical habitat model of benthic animals in the upper reaches of the Yangtze River, from the Xiangjiaba to Zhutuo sections by coupling the MIKE21 hydrodynamic model with a habitat model. This model coupled the changes in hydrological conditions and ecological processes to quantitatively reflect the effects of flow changes on river habitat quality, which can be used to predict the effects of hydrological changes on water ecosystems and provide fundamental information for ecological flow and scheduling decisions. Our results showed that by jointly regulating the suitable outflow of the Xiangjiaba Reservoir and the inflow of the Tuojiang, Minjiang, and Hengjiang rivers (three tributaries with water conservancy projects), the minimum flow in the non-flood season and the maximum flow in the flood season could be controlled more precisely. This increases the suitable habitat area for benthic animals as well as improves the stability of their habitat. This study fills the gap in the physical habitat model of benthic animals in the upper reaches of the Yangtze River as well as enriches the research ideas of ecological flow regulation. Moreover, this indicates the first application of the physical habitat model to the joint ecological flow regulation of the main tributaries, thus opening new directions for the application of the physical habitat model.

Plant Diversity and Distribution Patterns of Populus pruinosa Schrenk (Salicaceae) Floodplain Forests in Kazakhstan

Populus pruinosa is listed in the International Union for Conservation of Nature (IUCN) Red List of Threatened Species and the Red Data Book of Kazakhstan. The habitats of the species are associated with the floodplains of desert rivers, including the Syr Darya and the Ili. The reduction in tugai forests is associated with changes in the hydrological regimes of rivers, the reduction in groundwater, fires, and grazing. The aim of this research is to advance our knowledge of the woodlands and forests of P. pruinosa in Kazakhstan by analyzing the cenoflora and forestry characteristics, conducting ecological niche modeling to select suitable habitats for ecological restoration, and identifying rehabilitation strategies. The vegetation was studied using traditional methods of geobotanic field research in 2021 and 2022. Ecological niche modeling includes the calculation of all the environmental variables that are significant for the species, taken in their optimal ranges, and identifying the intersection of all the favorable conditions. To identify these variables, geographically linked meeting points of the studied species, climatic and soil conditions, relief characteristics identified by the SRTM and raster sets of the environmental variables (WorldClim), and distances to watercourses and settlements were accepted for consideration. A total of 102 environmental variables were used.

Balancing economic and ecological benefits for hydro-junction operation based on the ecological flow from the four major Chinese carps: a case study from Xinjiang River, China

The construction and utilization of the hydro-junctions would change the water flow and affect the hydrologic process required for the survival and reproduction of the aquatic organism in the river basin. To investigate the influence of the construction of the Jiepai (JP) and Bazizui hydro-junction (BZZ) on the hydrologic process in the Xinjiang River and coordinate the benefits between power generation and downstream ecological protection of the four major Chinese carps (FMCC), a one-dimensional hydrodynamic model is established to simulate the river hydrological regime of the spawning site before and after the construction of BZZ. Meanwhile, eleven ecological hydrologic parameters are used to evaluate the degree of hydrological changes for the spawning site caused by JP and BZZ, and four hydrological methods are applied to calculate the minimal and optimal ecological flows to satisfy the demands of FMCC. The multi-objective operation model combined with the non-dominated sorting genetic algorithm II(NSGA-II) is established to evaluate the relationship among the objective functions and design the ecological operation scheme of BZZ. The results indicate that the hydrologic changes in the spawning site has been moderately changed since the construction of the JP and would change more after the construction of BZZ. An obvious antagonistic relationship between electricity generating and ecological changes are presented in the simulation results, and the multiobjective operation model could clearly increase the comprehensive benefits under three typical years (dry, average, and abundant) by 20%, 19%, and 34% with the corresponding electricity generating lost by 4.9%, 3.5%, and 4.1%, respectively. This study is expected to provide scientific guidance to coordinate the restrictions and conflicts between economic and ecological benefits of hydro-junction operation in the lower reaches of the Xinjiang River.

Factors Determining the Replenishment of Pink Salmon Oncorhynchus gorbuscha (Salmonidae) on Iturup Island

Based on the data on the abundance of 53 generations of pink salmon Oncorhynchus gorbuscha of Iturup Island (spawners on spawning grounds, downstream migrating juveniles and the return of mature fish), a model describing the dependence of the abundance of mature pink salmon offspring on the initial abundance of generations and the effect of external factors was constructed using nonlinear regression analysis. The model explains about 80% of the replenishment variability, and it depends more on the effect of external factors in the freshwater period of life. The variability of replenishment is most closely related to factors related to the hydrological regime of rivers. The dependence of replenishment on the abundance of juveniles migrating downstream from spawning grounds, described by the dome-shaped curve, indicates the limiting effect of density factors on the formation of the abundance of pink salmon during the marine period of life. At the same time, a statistically significant effect of the abundance of juveniles released from fish hatcheries on the dynamics of the replenishment was not found.

Future of birds nesting on river islands in the conditions of hydrological variability caused by climate change

The mew gull (Larus canus), little tern (Sternula albifrons) and black-headed gull (Chroicocephalus ridibundus) are threatened in Poland by the loss of breeding habitats due to changes in the hydrological regime of rivers and the frequency and length of inundation. Analysis of daily flows generated from the SWAT model allowed us to obtain the values of hydrological characteristics expressed as Indicators of Hydrological Alteration (IHA) and find the relationship with collected data on nesting success on islands and sandbanks in the Middle Vistula from 2004 until 2018. For each bird species, a set of adjusted IHA was calculated for future scenarios (2021-2050 and 2071-2100). The projections were prepared on the basis of EURO-CORDEX and contain two scenarios of changes in greenhouse gas concentrations: RCP4.5 and RCP8.5. Catastrophic breeding seasons quantification was carried out to assess the number of years that will have unsuitable hydrological breeding conditions in the projected climate change. The mew gull noted the lowest nesting success (during 2004-2018) but it seems that hydrology is not the principal factor causing it. This species will experience an increase in high flows due to climate change in the far future scenarios. The black-headed gull is projected not to be affected by an increase in the percentage of catastrophic breeding seasons due to climate change. The little tern seems to be the most affected by projected climate change due to an increase in high flows and, in consequence, an increasing percentage of catastrophic breeding seasons. The results confirmed the importance of hydrologic change for avian nesting success.

Spatial Distribution and Risk Assessment of Heavy Metals in Surface Sediments from the Middle and Upper Reaches of the Yangtze River

The hydrological regime of rivers significantly changes after dam impoundment, which in turn affects the particle composition and heavy metal fractions of the river sediments. From June to July 2019, the sediments from 26 sampling sections were collected along the main stream of the Yangtze River from Panzhihua City in the upper reaches of the Yangtze River to Hukou City in the middle reaches of the Yangtze River. The concentrations and fractions of As, Cd, Co, Cr, Cu, Ni, Pb, and Zn were measured using the BCR three-step extraction procedure. The pollution status and potential ecological risk of heavy metals in sediments were evaluated using the geo-accumulation index, the sediment quality guideline, and the risk assessment coding method (RAC). The results showed that the average particle size of sediments in the upper reaches of the Yangtze River (Jinsha River cascade reservoir section and the Three Gorges reservoir section) decreased from upstream to downstream, the total concentrations of As and Zn increased, and the variation trend in the middle reaches was not obvious. The content of clay particles was significantly positively correlated with the acid-soluble fraction concentrations of Cd and Ni. Cd was mainly in the residual fraction (59.26%) and acid-soluble fraction (24.67%). Large parts of Cr and Ni were residual fractions accounting for 92.41% and 83.41%, respectively. As, Co, Cu, Pb, and Zn were mainly in the residual fraction and the reducible fraction. The order of decrease for the pollution degree (Igeo) of As, Cd, Co, Cr, Ni, and Zn was the Jinsha River, the middle reaches of the Yangtze River, and the Three Gorges Reservoir. The decrease order of bioavailability (RAC) of Cd, Co, Cr, Cu, Ni, and Zn was the Three Gorges Reservoir, the Jinsha River, and the middle reaches of the Yangtze River. The bioavailability of As and Pb decreased in the order of the middle reaches of the Yangtze River, the Three Gorges, and the Jinsha River. According to the classification of the RAC, Cd in the Three Gorges Reservoir area exhibited a high risk with the RAC accounting for 48.44%. Cu, Ni, and Zn showed a low or medium risk.

Assessing changing flow regime of upper and middle reaches of Narmada river using the indicators of hydrological alterations (IHA) metrics

ABSTRACT Researchers have long been trying to identify and estimate the impacts on the hydrological regime of rivers caused due to anthropogenic activities. In the present study, IHA was used to analyse the effect of dams on the flow regime of the upper and middle Narmada River. A total of 33 indicators were analysed to calculate Hydrological alteration due to dams in Narmada River. Average HA Index values of all 33 parameters are relatively higher for middle Narmada at Mandleshwar (0.86) than that of upper Narmada at Burmanghat (0.57). The average extreme water conditions have decreased both in frequency and in duration. Specifically, fewer floods and less low flow events have occurred in the post-dam period. The main purpose of this article is to identify and quantify the variations in the hydrologic regime so that the cumulative impacts of anthropogenic activities on water resources and the aquatic ecosystems may be reduced using proper water resource management strategies.

Determination of the maximum flow of the river with anthropogenic factors

This study was aimed to determine the anthropogenic and natural factors affecting hydrological regime of rivers, reliability and safety of hydroelectric facilities. The work of the Uchkurgan hydroelectric complex before and after the commissioning of the Toktogul reservoir with a hydroelectric power station is considered. The observations were conducted over a period of 92 years. A significant decrease in the unevenness of the average long-term water flow has been established for various periods. A homogeneity graph was built, which showed the periods of influence of anthropogenic factors in 1975 and 1990. The following scenarios for determining the maximum water discharges were considered: local water consumption regime, commissioning of the Toktogul reservoir, and energy mode. The estimated verification flow of 0.01% security satisfies the design capacity of the hydroelectric complex of 2720 m3/s..

ASSESSMENT OF THE RESERVOIRSꞋ IMPACT ON THE RIVER FLOW

In this article, the influence of reservoirs and ponds on the hydrological regime in the Yesil River basin is studied. To assess the impact of existing reservoirs on the annual runoff of rivers in the study basin, a simplified methodology of the State Hydrological Institute was used. The change in the annual (seasonal) runoff under the influence of ponds and reservoirs was determined using two methods: by the volume of filling the reservoirs; due to additional evaporation from the water surface of reservoirs compared to evaporation from land before their creation. When assessing the impact of ponds in terms of filling volumes or taking into account in the direct form of water intakes for economic needs, the influence of not only ponds, as artificial elements of the landscape, but also other factors of economic activity, was revealed. When assessing the impact of economic activities on the elements of the hydrological regime of rivers, including the creation of reservoirs for long-term regulation, changes in the climatic background are taken into account. According to the analysis of the results of assessing the impact on the runoff of the volumes of filling reservoirs, economic activities from 1974 to 2018 led to a decrease in runoff in the alignment of the river. Yesil - Nur-Sultan in the middle years of water availability (50% supply) by 30%, and in the mouth section. Yesil - Petropavlovsk city decrease in runoff up to 7%.

IMPACT OF FUTURE CLIMATE CHANGE ON RUNOFF IN LAKE ONEGO CATCHMENT AREA

The aim of this study is to predict the possible changes in runoff from Lake Onego catchment using the three largest tributaries Shuya, Suna and Vodla as a case study for assessing expected climate change in the 21st century in accordance with the greenhouse gas emission scenarios RCP 2.6 and RCP 8.5 – the best and the worst in terms of environmental impact, respectively. Information about the change in meteorological elements required for runoff calculations was obtained on the basis of the climate models MPI-ESM-MR and IPSL-CM5A. To assess the possible change in runoff as a result of changes in the regional climate, the runoff model ILHM was used. When both climate models are applied, a significant increase in air temperature in the RCP 8.5 scenario leads to an increase in the estimated values of evaporation, which largely compensates for the increase in river runoff due to increased precipitation. In the RCP 2.6 scenario, there are no significant changes in evaporation. A combination of RCP 2.6 and MPI-ESM-MR produces a slight decrease in runoff by the end of the 21st century. It can be assumed that the change in runoff from the catchment of Lake Onego will be in the interval between the estimates made in the two extreme scenarios and one should not expect extreme changes in the hydrological regime of rivers in this region.

Spatiotemporal dynamics of surface sediment characteristics and benthic macrofauna compositions in a temperate high-energy River-dominated Ocean Margin

The benthic compartment of River-dominated Ocean Margins (RiOMar) is largely affected by sedimentary processes, as well as by natural and anthropogenic disturbances. Recent studies have confirmed the major importance of riverine inputs and local hydrodynamics in the spatial structuration of low- and high-energy temperate RiOMar, respectively. Differences in the nature of these structuring factors could also affect the temporal dynamics of these two types of systems. The present study is aiming at: (1) quantifying spatiotemporal changes in surface sediment and benthic macrofauna within the West Gironde Mud Patch (WGMP; high-energy system) over both short (2016–2018) and longer (2010/2016–2018) time scales, (2) identifying the main environmental factors explaining those changes, and (3) achieving a comparison with the Rhône River Prodelta (RRP; low-energy system) in view of further characterizing the functioning of the benthic components of these two temperate RiOMar. Surface sediment characteristics (grain size, quantitative and qualitative descriptors of particulate organic matter) and benthic macrofauna compositions were assessed based on 4 seasonal sampling of 5 stations located along a depth gradient within the WGMP. Results highlighted the existence of spatial patterns for both surface sediment and benthic macrofauna, which are both better explained by local hydrodynamics. Most variables presented seasonal changes. Benthic macrofauna compositions also showed pluri-annual changes, which were attributed to a cicatrization process following a major disturbance caused by the 2013–2014 series of severe winter storms, and suggests the major role of local hydrodynamics in explaining 2010/2016–2018 temporal changes in WGMP benthic macrofauna compositions. The comparison with the RRP further highlighted major discrepancies between the two systems in the main processes (i.e., hydrodynamics versus river hydrological regime) explaining surface sediment characteristics and benthic macrofauna compositions, which supports current RiOMar typologies.