Medium-sized Basins Research Articles

A simulation study of deepwater ventilation in fjords through artificial downwelling

The pumping of less dense surface water into a deep layer, also termed artificial downwelling (AD), has demonstrated its effectiveness in ventilating basin water in a few fjords. Building on a previous experiment in By Fjord, we established a well-calibrated far-field hydrodynamic model to simulate bottom water circulation caused by AD implementation. Our simulations suggest that (1) laterally closed boundaries are crucial for AD to cause spatially uniform compensatory downwelling in the bottom water and that (2) dissolved oxygen delivered through downwelling can be sourced from both surface waters and below the pycnocline to enhance oxygen levels effectively. We propose a physical oxygen budget model to predict the temporal variability of deep-water oxygen levels, offering guidelines on the number of pipes and flow rates required for large-scale oxygenation. For small fjords (∼1 km2), a few pipes (each has a flow rate of 1 m3 s−1) may suffice, while medium-sized basins like Chesapeake Bay (∼1000 km2) may require several hundred pipes.

Dune elongation and hunting strategy during the Terminal Pleistocene (Ramonian): Insights from Mizpor Ashalim, northwestern Negev dunefield margins, Israel

The Middle Epipalaeolithic Ramonian culture, endemic to the Negev-Sinai desert, incorporates highland occupations alongside lowland dune-associated localities. The lowland sites, dominated by microlithic tools, have been hypothesized to be prime hunting settings. Here we investigate this hypothesis based on the data from Mizpor Ashalim - a new Ramonian site located upon a falling dune overlooking the central Besor Valley. The study incorporates analysis of projectile damage on microlithic tools, geomorphology, portable OSL profiling, and OSL ages of the dune deposits, as well as Normalized Difference Vegetation Index (NDVI) investigation. GIS mapping of relevant sites alongside the ancient dune-dammed water bodies constitutes an additional methodological tool newly applied in the current study.The results support the hypothesis and suggest that Ramonian hunting strategy was associated with dune-dammed, medium-sized basins that formed ecological niches following winter floods. The study sheds new light on adaptations developed by different cultural entities occupying the region during the Terminal Pleistocene and their connection with changing environmental settings. At the same time, it emphasizes technological continuity throughout the cultural sequence in the arid environments of the Southern Levant, expressed in microliths production and projectile design. This continuity, not observed in the Mediterranean climate zone, underscores the importance of understanding the social and economic dynamics in the desert areas of the Southern Levant to comprehend the processes that led to sedentism and food production in the region.

Evolution of Italy-Greece Passenger Maritime Transport: a Multi-level Study to Estimate the Factors Influencing the Demand and Supply of Passenger Ferry Transport

In recent years, the shipping and maritime transport segment has undergone profound changes. Faced with the need to achieve the sustainability goals set by Agenda 2030, different sustainable modes of transport must therefore be evaluated. Passenger transport by ship has proven to be the least polluting per pax/km. Different European regulations are moving in the direction of limiting transport by air when there are fewer polluting methods on average lengths, mainly on a national scale. The tourism sector is one where the impacts on the Agenda 2030 goals are often not properly assessed. Ship connections with a tourism function are central in connections to smaller islands which, due to their size and relatively small flows, do not have airports. In medium-sized basins, tourist traffic by ship is changeable and often dependent on specific characteristics of the basin. The aim of the present research work is to analyse the general case of an open basin, with an application to the Adriatic-Ionian basin. The system of connections between eastern Italy and western Greece by ship is analysed. The case study refers to the characteristics of travel from Italy to Greece by ship, with reference to the Ionian Islands. The overall method proposed is articulated in several successive steps, which can be summarised as follows: analysis of the characteristics of services; analysis of supply with network analysis methods applied to services; analysis of demand with estimation of a regression model. The methodologies identified make it possible to highlight the temporal and central characteristics of the network considered, and at the same time to verify the influence that certain attributes have on tourism for the area studied. The results show, on the one hand, that not all services have a significant summer component and, on the other, that the centrality of the various ports within the network changes, even heavily, with the season. The work is expected to be of particular interest to policy makers, planners, and researchers, considering centrality as closely linked to the distribution of services for passengers in ports and related port-city areas, and considering the possibility of better planning the distribution of funding in relation to the ports’ development and resilience to address disruptive events.

Predictability of water resources with global climate models. Case of Northern Tunisia

The objective of the research is to explore the predictability of water resources directly with GCMs by analysing long-term effects of climate change on Northern Tunisia’s blue and green water. Hydrologic impacts rely on a rainfall-runoff lumped model using outputs of CMIP6 GCMs within the framework of the ssp2-45 scenario. Among the 30 CMIP6 models, the composite cnrm-esm2-1 and fgoals-g3 best restore observed runoff from 1995 to 2014 and give the best GCM. Hydrologic projections 2015–2100 show significant drops in rainfall (9%), runoff (21%), groundwater recharge (15%), as well as for green water (6%). The results show that the use of raw GCMs predictions on large basins is possible and provides precisions comparable to what is produced when using Regional Climate Models in medium size basins.

Quantitative estimation and fusion optimization of radar rainfall in the Duanzhuang watershed at the eastern foot of the Taihang Mountains

Abstract The temporal and spatial resolutions of rainfall data directly affect the accuracy of hydrological simulation. Weather radar has been used in business in China, but the uncertainty of data is large. At present, research on radar data and fusion in small and medium-sized basins in China is very weak. In this paper, taking the Duanzhuang watershed as an example, based on station data, Shijiazhuang's radar data are preprocessed, optimized and fused. Eleven rainfall events are selected for fusion by three methods and quality evaluation, and three flood simulations are used to test their effect. The results show that preprocessing and initial optimization have poor effects on radar data improvement. The rainfall proportional coefficient fusion method performs best in rainfall spatial estimation, where the R2 values of the three inspection stations are increased to 0.51, 0.78 and 0.82. Three fusion datasets in the peak flow and flood volume of flood simulation perform better than station data. For example, in the No.20210721 flood, the NSE of the three fusion data increased by 39, 30 and 48%. This shows that the fusion method can effectively improve the data accuracy of radar and can obtain high temporal and spatial resolution rainfall data.

Sensitivity Study of Seismic Amplification Effect of Large-Scale Sichuan Basin on Key Parameters During the Great Wenchuan Earthquake

The effect of soil parameters on basin amplification effect has been widely investigated, especially for the small and medium-sized basins under plane wave incidence or point source ruptures. However, the sensitivities of seismic amplification effect of large-scale basins with respect to soil parameters during great earthquakes with tremendous rupture faults have obtained relatively less attention. In this paper, based on the established three-dimensional Sichuan basin model, the effects of four material parameters of the basin sediments, including the shear wave velocity, Poisson’s ratio, and the shear quality factor of the Quaternary sediment, as well as the velocity of the rock above the basin crystalline basement (which will be referred as SVQS, PRQS, QFQS, and VCBR, respectively), on the long-period wave amplification patterns of the Sichuan basin during the great Wenchuan earthquake are investigated by using the spectral element method and parallel computing technique. The results show the following: (1) SVQS has the greatest influence on the basin horizontal component ground motions, while the vertical component is comparably insensitive to it. (2) PRQS demonstrates comparable effects on the horizontal and vertical basin ground motions. With the increase of PRQS, the amplitudes and regions of the strong shakings both become smaller. However, the influence of PRQS is less significant compared with SVQS and VCBR. (3) QFQS mainly affects the relatively high-frequency motions inside the basin, and the low-frequency motions are generally insensitive to it. With the reduction of QFQS, the amplitudes and regions of the basin strong ground motions turn a little smaller, but the distribution features are generally unchanged. (4) Effects of VCBR on the horizontal and vertical component basin ground motions are opposite. With the growth of VCBR, the amplitudes and areas of strong horizontal motions increase consequently, but they decrease for the vertical component.

Study of Flood Simulation in Small and Medium-Sized Basins Based on the Liuxihe Model

The uneven distribution of meteorological stations in small and medium-sized watersheds in China and the lack of measured hydrological data have led to difficulty in flood simulation and low accuracy in flood forecasting. Traditional hydrological models no longer achieve the forecasting accuracy needed for flood prevention. To improve the simulation accuracy of floods and maximize the use of hydrological information from small and medium-sized watersheds, high-precision hydrological models are needed as a support mechanism. This paper explores the applicability of the Liuxihe model for flood simulation in the Caojiang river basin and we compare flood simulation results of the Liuxihe model with a traditional hydrological model (Xinanjiang model). The results show that the Liuxihe model provides excellent simulation of field floods in Caojiang river basin. The average Nash–Sutcliffe coefficient is 0.73, the average correlation coefficient is 0.9, the average flood peak present error is 0.33, and the average peak simulation accuracy is 93.9%. Compared with the traditional flood hydrological model, the Liuxihe model simulates floods better with less measured hydrological information. In addition, we found that the particle swarm optimization (PSO) algorithm can improve the simulation of the model, and its practical application only needs one representative flood for parameter optimization, which is suitable for areas with little hydrological information. The study can support flood forecasting in the Caojiang river basin and provide a reference for the preparation of flood forecasting schemes in other small and medium-sized watersheds.

Geomorphic, environmental, and archeological significance of Last Glacial Maximum to middle Holocene dune damming, northwestern Negev dunefield margin, Israel

Aeolian-Fluvial (AF) stratigraphic sequences record the bilateral impact of aeolian and fluvial systems upon each other. Along dunefield margins, AF sequences document shifts from fluvial-dominated environments to aeolian-dominated environments mainly in the form of dunes damming and impounding fluvial systems. We report on a 200 m-long exposure, documenting AF sequences in a medium-sized (64 km2) basin along the northwestern Negev desert dunefield margins.Remains of five dune morphologies abutted and overlapped by ever-emptying dune-dammed waterbody deposits record three major OSL-dated dune encroachment phases. Two distinct dune encroachments dated to the Last Glacial Maximum (LGM) at 27–21.5 ka constructed a dune-dammed environment, maintained by post-LGM encroachments at 19.3–17.3 ka and 14.5–13.1 ka. The dune-damming of the ancient basin led to the formation of short-term waterbodies, which accommodated two types of deposits: (i) basal massive clay-silty loam units whose buildup decreased the fluvial accommodation space; and (ii) overlaying event-based sedimentary couplets deposited in shallower waterbodies, which led to upstream widening of a playa-like alluvial plain during the early to middle-Holocene (9.8–5 ka). Epipalaeolithic and Chalcolithic campsites upon these deposits chronologically correlate to the post-LGM development and persistence of these waterbodies.The uppermost early to middle Holocene deposition of couplets that lags the last recorded dune encroachment indicates that the transition from aeolian to fluvial domination was gradual and lasted more than 5 kyr. The onset of the Holocene characterized by regional dune stabilization and shallow accommodation space upstream of the damming-dune, records a climatic shift and a geomorphic response to diminishing loess at the upper basin which increased hydrological regime. AF palaeo-archives thus provide us with indirect evidence of palaeoclimate transitions and both aeolian and fluvial geomorphic responses, that also complement and compensate inherent OSL dating constraints involved with OSL-dating of dunefields.

Shale gas accumulation patterns in China

Although significant progress has been made in the geological theory and exploration and development of shale gas in China, the research on the geological particularity and enrichment regularity associated with shale gas accumulation remains weak. With this in mind, we analyzed the shale gas accumulation patterns in China. The findings show that: (1) A variety of organic-rich shales were deposited in the continental margin-type marine and transitional environments during the Pre-Mesozoic period and the basin-type terrestrial environment during the Mesozoic and Cenozoic eras. (2) The basins dominated by Mesozoic and Cenozoic terrestrial sediments superimpose on the Pre-Mesozoic continental margin-type marine–or transitional-facies sediments. The former developed the terrestrial shales with large thickness, high organic matter abundance, new age, and low thermal maturity; meanwhile, the deep parts of the basins are favorable for shale gas enrichment. However, the latter preserves the shale with old age, high thermal maturity, and undergoing multiphase tectonic movements; and the tectonically stable regions are favorable for shale gas enrichment. (3) The aulacogens mainly formed in the Meso-Neoproterozoic, Sinian-Ordovician, and Devon-Triassic periods are favorable for marine organic-rich shale deposition; moreover, this type of shale and other types including transitional facies shales with favorable reservoir-forming assemblages, coal-measure shales in small and medium-sized basins, and low-medium mature shales affected by magma intrusion, have jointly constituted the various shale gas accumulation patterns in China. (4) Based on the drilling discoveries in China, shale gas accumulation patterns can be categorized into two types: tectonic-controlled and stratigraphic-controlled. The former is mainly related to structural features, whereas the latter is mainly related to the variation of lithology and strata. (5) Shale development and gas content are mainly affected and controlled by geological factors including sedimentation, diagenesis, and later tectonic movements. Favorable sedimentary environments, appropriate thermal maturity, good sealing capacity of caprock, and excellent structural preservation are the necessary conditions for shale gas enrichment.

Assessment of Model-Derived Mass Flux Relative to Satellite Gravimetry via a Water Balance in North America

Abstract GRACE and GRACE Follow-On (GRACE-FO) mission data are utilized to assess mass flux derived from the North American Regional Reanalysis (NARR) and the NLDAS-2 Noah land surface model via multiple water balance formulations. Water balances are computed for 18 medium size basins in North America at the USGS Watershed Boundary Dataset HU2 level over the span of the GRACE and GRACE-FO missions (2002–21). Performance of model-derived mass flux is presented in the context of statistical agreement to changes in terrestrial water storage (ΔTWS) derived from Center for Space Research (CSR) GRACE RL06 mass concentrations (mascons), and GRACE and NARR uncertainty is estimated against comparable datasets. The land surface water balance method utilizing NLDAS-2 Noah consistently outperforms the total column method utilizing NARR, which is likely due to enhanced precipitation forcing and an updated Noah model version used in NLDAS-2. The surface approach to the calculation of atmospheric moisture flux divergence is carried through the presented analyses and is demonstrated to be comparable in performance to the more common volume approach. Mass balance methodology, basin characteristics, and ΔTWS signal characteristics are assessed to quantify effects on model performance and while factors such as basin size, basin average topography gradient, and ΔTWS annual amplitude are shown to have a measurable effect on model performance, no single factor exhibited a dominant or consistent effect. Drought conditions are shown to have a significant temporally localized effect on model-derived mass flux accuracy, with NARR being particularly susceptible to this effect. Significance Statement Measurements of Earth’s gravity field from the GRACE and GRACE-FO satellite missions are utilized to create estimates of water storage changes in 18 North American river basins that are compared to changes in water storage calculated from an atmospheric model reanalysis (NARR) and a land surface model (NLDAS-2 Noah). The resulting comparison demonstrates that certain basin characteristics can have a slight effect on model accuracy, while climatic conditions such as drought can have a major impact on model accuracy. This work provides useful quantification of when and where modeled water transport loses accuracy, which is integral to our understanding of the present and future distribution of this crucial resource and the natural processes that affect it.

Nitrogen and phosphorus load estimation of inflow rivers to Yuqiao Reservoir based on GWLF model

Watershed model technology was an important tool for non-point source pollution prevention and control. In order to figure out the total nitrogen (TN) and total phosphorus (TP) load of inflow rivers to Yuqiao Reservoir in 2021, GWLF model was used to simulate the hydrologic process in its sub-basin. Firstly, the hydrological parameters of the model were determined by the measured meteorological and hydrological data. Secondly, the hydrological parameters were extended to the whole basin, and the three main river inflows to Yuqiao Reservoir were simulated in 2021. Lastly, the nutrient loads were estimated by multiplying the simulated inflow as mentioned above by the observed TN and TP concentration data at the same site. The results showed that the TN and TP load of inflow rivers was 7 106.9 t and 80.0 t, respectively, of which the flood period from July to August contributed 55.3% and 69.3%, respectively. GWLF model was effective in simulating hydrological processes in the study area. The Nash efficiency coefficients of the calibration and the validation period were 0.89 and 0.91, respectively. GWLF model was suitable for hydrological simulation and estimation of non-point source pollution load in small and medium-sized basins.

Flash Flood Susceptibility Mapping in Sinai, Egypt Using Hydromorphic Data, Principal Component Analysis and Logistic Regression

Flash floods in the Sinai often cause significant damage to infrastructure and even loss of life. In this study, the susceptibility to flash flooding is determined using hydro-morphometric characteristics of the catchments. Basins and their hydro-morphometric features are derived from a digital elevation model from NASA Earthdata. Principal component analysis is used to identify principal components with a clear physical meaning that explains most of the variation in the data. The probability of flash flooding is estimated by logistic regression using the principal components as predictors and by fitting the model to flash flood observations. The model prediction results are cross validated. The logistic model is used to classify Sinai basins into four classes: low, moderate, high and very high susceptibility to flash flooding. The map indicating the susceptibility to flash flooding in Sinai shows that the large basins in the mountain ranges of the southern Sinai have a very high susceptibility for flash flooding, several basins in the southwest Sinai have a high or moderate susceptibility to flash flooding, some sub-basins of wadi El-Arish in the center have a high susceptibility to flash flooding, while smaller to medium-sized basins in flatter areas in the center and north usually have a moderate or low susceptibility to flash flooding. These results are consistent with observations of flash floods that occurred in different regions of the Sinai and with the findings or predictions of other studies.

Surface Water Flow Balance of a River Basin Using a Shallow Water Approach and GPU Parallel Computing—Pescara River (Italy) as Test Case

The analysis and prevention of hydrogeological risks plays a very important role and, currently, much attention is paid to advanced numerical models that correspond more to physical reality and whose aim is to reproduce complex environmental phenomena even for long times and on large spatial scales. Within this context, the feasibility of performing an effective balance of surface water flow relating to several months was explored, based on accurate hydraulic and mathematical-numerical models applied to a system at the scale of a hydrographic basin. To pursue this target, a 2D Riemann–Godunov shallow-water approach, solved in parallel on a graphical processing unit (GPU), able to drastically reduce calculation time, and implemented into the RiverFlow2D code (2017 version), was selected. Infiltration and evapotranspiration were included but in a simplified way, in order to face the calibration and validation simulations and because, despite the parallel approach, it is very demanding even for the computer time requirement. As a test case the Pescara river basin, located in Abruzzo, Central Italy, covering an area of 813 km2 and well representative of a typical medium-sized basin, was selected. The topography was described by a 10 × 10 m digital terrain model (DTM), covered by about 1,700,000 triangular elements, equipped with 11 rain gauges, distributed over the entire area, with some hydrometers and some fluviometric stations. Calibration, and validation were performed considering the flow data measured at a station located in close proximity to the mouth of the river. The comparison between the numerical and measured data, and also from a statistical point of view, was quite satisfactory. A further important outcome was the capability to highlight any differences between the numerical flow-rate balance carried out on the basis of the contributions of all known sources and the values actually measured. This characteristic of the applied modeling allows better calibration and verification not only of the effectiveness of much more simplified approaches, but also the entire network of measurement stations and could suggest the need for a more in-depth exploration of the territory in question. It would also enable the eventual identification of further hidden supplies of water inventory from underground sources and, accordingly, to enlarge the hydrographic and hydrogeological border of the basin under study. Moreover, the parallel computing platform would also allow the development of effective early warning systems, for example, of floods.

Wildfires and Monsoons: Cryptic Drivers for Highly Variable Provenance Signals within a Carboniferous Fluvial System

Sediment delivery and supply are explicitly controlled by variations in broad-scale processes such as climate, tectonics and eustasy. These in turn influence fluvial processes and hinterland evolution. A bespoke multi-proxy approach (integrating apatite and zircon U-Pb geochronology, trace elements in apatite, and Pb-in-K-feldspar provenance tools) coupled with outcrop investigation is used to constrain the temporal trends in sediment delivery to channel sandstones of the fluvio-estuarine mid-Viséan Mullaghmore Sandstone Formation, Ireland. Provenance data indicate unique detrital signatures for all sampled horizons, indicating the fluctuating nature of sediment supply to this medium-sized basin. Tectonism and/or abrupt relative sea-level fall likely caused fluvial rejuvenation, resulting in local basement sourcing of the initial fill. Older and more distal sources, such as the Nagssugtoqidian Belt of East Greenland, become more prominent in stratigraphically younger channel sandstones suggesting catchment expansion. Paleoproterozoic to Mesoproterozoic sources are most dominant, yet the detrital grain cargo varies in each channel sandstone. Proximal sources such as the Donegal Batholith and Dalradian Supergroup are variable and appear to switch on and off. These signal shifts are likely the result of channel migration and paleoclimatic fluctuation. A monsoonal climate and large-scale wildfire events (evidenced by fusain) likely contributed to modify plant cover, intensify erosion, and increase run-off and sediment delivery rates from specific areas of the hinterland.

Hydrological Analysis of Extreme Rain Events in a Medium-Sized Basin

The hydrological response of a medium-sized watershed with both rural and urban characteristics was investigated through event-based modeling. Different meteorological event conditions were examined, such as events of high precipitation intensity, double hydrological peak, and mainly normal to wet antecedent moisture conditions. Analysis of the hydrometric features of the precipitation events was conducted by comparing the different rainfall time intervals, the total volume of water, and the precedent soil moisture. Parameter model calibration and validation were performed for rainfall events under similar conditions, examined in pairs, in order to verify two hydrological models, the lumped HEC-HMS (Hydrologic Engineering Center’s Hydrologic Modeling System model) and the semi-distributed HBV-light (a recent version of Hydrologiska Byråns Vattenbalansavdelning model), at the exit of six individual gauged sub-basins. Model verification was achieved by using the Nash–Sutcliffe efficiency and volume error index. Different time of concentration (Tc) formulas are better applied to the sub-watersheds with respect to the dominant land uses, classifying the Tc among the most sensitive parameters that influence the time of appearance and the magnitude of the peak modeled flow through the HEC-HMS model. The maximum water content of the soil box (FC) affects most the peak flow via the HBV-light model, whereas the MAXBAS parameter has the greatest effect on the displayed time of peak discharge. The modeling results show that the HBV-light performed better in the events that had less precipitation volume compared to their pairs. The event with the higher total precipitated water produced better results with the HEC-HMS model, whereas the rest of the two high precipitation events performed satisfactorily with both models. April to July is a flood hazard period that will be worsened with the effect of climate change. The suggested calibrated parameters for severe precipitation events can be used for the prediction of future events with similar features. The above results can be used in the water resources management of the basin.

Temporary dependency of parameter sensitivity for different flood types

Abstract Hydrological and climatic data at finer temporal resolutions are considered essential to model hydrological processes, especially for short duration flood events. Parameter transferability is an essential approach to obtain sub-daily hydrological simulations at many regions without sub-daily data. In this study, the objective is to investigate temporary dependency of parameter sensitivity for different flood types, which contributes to research into parameter transferability. This study is conducted in a medium-sized basin using a distributed hydrological model, DHSVM. Thirty-six flood events in the period of 04/12/2006–07/01/2013 in the Jinhua River basin, China, are classified into three flood types (FF: flash flood, SRF: short rainfall flood and LRF: long rainfall flood) by using the fuzzy decision tree method. The results show that SRF is the dominant flood type in the study area, followed by LRF and FF. Runoff simulations of FF and SRF are more sensitive to parameter perturbations than those of LRF. Sensitive parameters are highly dependent on temporal resolutions. The temporary dependency of LRF is the highest, followed by SRF and FF. More attention should be payed to sensitive and highly temporal dependent parameters in a subsequent parameter transfer process. Further study into this result is required to test the applicability.

Multifractal Characteristics Analysis Based on Slope Distribution Probability in the Yellow River Basin, China

Multifractal theory provides a reliable method for the scientific quantification of the geomorphological features of basins. However, most of the existing research has investigated small and medium-sized basins rather than complex and large basins. In this study, the Yellow River Basin and its sub-basins were selected as the research areas, and the generalized fractal dimension and multifractal spectrum were computed and analyzed with a multifractal technique based on the slope distribution probability. The results showed that the Yellow River Basin and its sub-basins exhibit clear multifractal characteristics, which indicates that the multifractal theory can be applied well to the analysis of large-scale basin geomorphological features. We also concluded that the region with the most uneven terrain is the Yellow River Downstream Basin with the “overhanging river”, followed by the Weihe River Basin, the Yellow River Mainstream Basin, and the Fenhe River Basin. Multifractal analysis can reflect the geomorphological feature information of the basins comprehensively with the generalized fractal dimension and the multifractal spectrum. There is a strong correlation between some common topographic parameters and multifractal parameters, and the correlation coefficients between them are greater than 0.8. The results provide a scientific basis for analyzing the geomorphic characteristics of large-scale basins and for the further research of the morphogenesis of the forms.

Оценка эластичности стока рек восточной части бассейна Амура

Taking into account the unstable moisture regime and the diversity of landscapes within the Amur River basin, the problem of assessing the impact of climatic changes on the processes of surface water cycle in the region becomes multifaceted, associated with the solution of particular problems. This work studied the reaction of a river runoff to changes in the amount of atmospheric precipitation on the basis of the elasticity coefficient. Small and medium-sized river basins (52 in total) belonging to the system of the Middle and Lower Amur are the objects of this study. The data of standard observations at hydrological posts and meteorological points for the summer-autumn flood hazard period (June-September) were used. The data series were selected to include different moisture conditions. It was found that with an increase in precipitation by 1 %, the river runoff in the flood hazard season has increased by 1.02–3.86 % in 48 cases, and decreased in 4 cases. The results of the work are fundamentally close to the regional estimates within the basin of the Amur River on the base of the analysis of factual material (including the near abroad) and simulation results, as well as to the values of the runoff elasticity coefficient obtained in different geographic zones and given in the specialized literature. The relationship between the elasticity coefficient values of runoff with various basin indicators has been studied. For the rivers in the Primorsky Kray (catchment area of the Ussuri River), the relationship between the elasticity coefficient values and the seasonal runoff and precipitation, the runoff coefficient, average height, catchments slopes and average river network slopes has been revealed. The influence of local conditions of runoff formation on the river basins response to changes in the amount of atmospheric precipitation is discussed.

The applicability of ASCS_LSTM_ATT model for water level prediction in small- and medium-sized basins in China

Abstract Water level prediction of small- and medium-sized rivers plays an important role in water resource management and flood control. Such a prediction is concentrated in the flood season because of the frequent occurrence of flood disasters in the plain area. Moreover, the flood in mountainous areas suddenly rises and falls, and the slope is steep. Thus, establishing a hydrological prediction model for small- and medium-sized rivers with high accuracy and different topographic features, that is, plains and mountains, is an urgent problem. A prediction method based on ASCS_LSTM_ATT is proposed to solve this problem. First, the important parameters are optimized by improving the cuckoo search algorithm. Second, different methods are used to determine the forecast factors according to various topographic features. Finally, the model is combined with the self-attention mechanism to extract significant information. Experiments demonstrate that the proposed model has the ability to effectively improve the water level prediction accuracy and parameter optimization efficiency.

Tectonic link between the Neoproterozoic dextral shear fabrics and Cenozoic extension structures of the Mekelle basin, Northern Ethiopia

The Mekelle basin (area similar to 5500 km(2)) is located at the immediate western margin of the Afar Depression, which has a history of collision, subsidence, uplift, magmatism and now rifting. The evolution of such small to medium size basins as the Mekelle in a complicated geodynamic set-up is a subject of debate, because several different mechanisms of basin formation could apply. To address the possible basin evolution scenarios, we combine structural and dynamic analyses of northern Ethiopia, with strong emphasis on the basin and basin bounding basement rocks. The northern basin bounding block is uplifted by about 1500 m compared with the western and southwestern basin-bounding blocks. In the basin, superposition of large-scale orthogonal brittle shear fabrics and the development of young, parallel to subparallel extensional fractures and domino faulting have produced a total of similar to 2200 m vertical displacement. These observations, coupled with the absence of gradual roll-down of the internal basin (i.e., absence of bending/folding of an elastic beam supported at both ends), imply that Mekelle basin is not an IntraCONtinental Sags (ICONS) or plate interior basin, as previously described, but is instead a multi-tectonic triggered basin. Integrated satellite images using ground-controlled measurements and deep borehole data were used to decipher the entire evolution of the basin starting from the late-collisional deformation through the regional up-doming to the sills/dikes injection and basin formation.