Variations In Water Discharge Research Articles

Physical model case study: treatment effect of soft ground by vacuum preloading combined with liquid bag pressurization method

Vacuum preloading and composite ground reinforcement are commonly used methods for reinforcing soft soil, but there is a lack of integrated design method for vacuum preloading combined with composite ground. This case study introduces an innovative approach that combines vacuum preloading with liquid bag pressurization to achieve the integrated design of consolidation drainage method and composite ground reinforcement, which is different from the reported air bag pressurization. To illustrate the effectiveness of this method. Model tests were carried out to analyze the variation of water discharge, pore water pressure, ground settlement, and average consolidation degree in the process of vacuum consolidation. The study investigated the water content, undrained shear strength, and ground bearing capacity of composite ground after ground treatment. A correlation between average undrained shear strength and characteristic value of ground-bearing capacity was established to evaluate and predict the treatment effect of composite ground. Research shows that compared with traditional vacuum preloading, the undrained shear strength can be increased by 13.78%–65.08%, and the characteristic value of bearing capacity for the composite ground can be enlarged by 2.3–4 times. These results indicate that the vacuum preloading combined with liquid bag pressurization can significantly improve reinforcement effect on soft ground.

Ship scheduling problem in an anchorage-to-quay channel with water discharge restrictions

The optimization of ship scheduling in water-land transshipment plays a crucial part in enhancing transportation efficiency and alleviating traffic congestion on inland waterways, particularly when the service capacity of locks is insufficient. This study focuses on the ship scheduling problem in an anchorage-to-quay channel, where the navigation of ships is influenced by the water discharge during flood seasons. A new mixed-integer linear programming (MILP) model is formulated for this problem, in which the interconnected decision of ships’ navigation and berthing activities, the variation of water discharge in the waterway channel, and the change of navigation scenarios (i.e., normal or flood impact) are explicitly taken into account. Then a multi-population genetic algorithm (MPGA) is applied to solve this model. Numerical experiments conducted for the Three Gorges Dam (TGD) demonstrated that the proposed heuristic method can tackle the ship scheduling problem within a reasonable time, which is also effective in assisting ships to match acceptable water discharge time window by slightly adjusting the departure time of ships at the anchorage or quay. Furthermore, the proposed method can ensure the navigational safety of ships and improve the efficiency of ship transportation in different scenarios, and quantitatively evaluate the water discharge impact.

Scour-depth variability controls channel-scale stratigraphy in experimental braided rivers

ABSTRACT Braided rivers distribute sediment across landscapes, often forming wide channel belts that are preserved in stratigraphy as coarse-grained deposits. Theoretical work has established quantitative links between the depth distribution of formative channels in a braided river and the geometry of their preserved strata. However, testing these predictive relationships between geomorphic process and stratigraphic product requires examining how braided rivers and their deposits coevolve, with high resolution in both space and time. Here, using a series of four runs of a physical experiment, we examine the controls of water discharge and slope on the resulting geometry of preserved deposits. Specifically, we focus on how a twofold variation in water discharge and initial riverbed slope affects the spatiotemporal distribution of channel depths and the geometry of preserved deposits of a braided river. We find that the channel depths in the laboratory experiment are described by a two-parameter gamma distribution and the deepest scours correspond to zones of erosion at channel-belt margins and channel-thread confluences in the channel belt. We use a reduced-complexity flow model to reconstruct flow depths, which were shallower compared to channel thalweg depths. Synthetic stratigraphy built from timeseries of topographic surfaces shows that the distribution of cut-and-fill-unit thickness is invariant across the experiments and is determined by the variability in scour depths. We show that the distribution of cut-and-fill-unit thickness can be used to reconstruct formative-channel-depth distributions and that the mean thickness of these units is 0.31 to 0.62 times the mean formative flow depth across all experiments. Our results suggest that variations in discharge and slope do not translate to measurable differences in preserved cut-and-fill-unit thickness, suggesting that changes in external forcings are likely to be preserved in braided river deposits only when they exceed a certain threshold of change.

Variation of material fluxes in a large heterogenic subtropical river: A combination of climate change and human damming influences

Study regionThe West River, the main tributary of the Pearl River, China Study focusA hydrological model of the West River was successfully established and used to quantify the role of basin-wide spatiotemporal change of the impacts of climate change and human damming activities in the variation of material fluxes (water discharge and sediment load) at the river outlet at both interannual and seasonal time scales of the period from 1975 to 2017. New hydrological insights for the regionThe interannual variations of water discharge and sediment load were controlled by a single factor locally: runoff variation was positively correlated with the ENSO index (r = 0.56, p < 0.001) and the dams caused a 75.1% reduction of the annual sediment load in the post-dam period (2009–2017). Seasonally, climate change can alter the monthly water discharge by − 12–23% in the latter half of an abnormal year, while the dams caused a 4.6% reduction and a 12.4% increase in the summer and winter sediment load, respectively. There was a strong interaction between the two influencing factors seasonally, particularly during the wetter summer or drier winter, wherein the dominant driving mechanism in the monthly variation of material fluxes can switch. For the river basin, the impacts of climate change and dams are spatially variable. The basin-wide spatiotemporal change of the impacts of climate change and human damming activities can complicate the hydrological signal at the river outlet.

Modelling of Sediment Transport and Deposition in Generating River-Mouth Closure: Oum-Errabia River, Morocco

River mouths are dynamic systems that can respond rapidly to both fluxes in fluvial water and sediment discharge and marine energy conditions, notably waves. On semi-arid wave-exposed coasts, the morphosedimentary behaviour of river mouths is particularly sensitive to variations in water discharge, which can be significantly influenced by climate variations, in addition to anthropogenic actions such as the construction of dams for water resource needs. In this climatic setting, an increasingly common consequence of decreasing river water discharge is the more or less prolonged closure of river mouths. Most studies have addressed river-mouth closure using analytical, parametric, numerical, or statistical models. The present study uses output from four numerical models to elucidate the hydrodynamic and sedimentary behaviour of the mouth of the Oum-Errabia River (catchment size: 35,000 km2), which debouches on the Atlantic coast of Morocco. The historical evolution of the river mouth and the impact of human interventions, such as the construction of dams, are discussed. The study also briefly discusses the impact of the recent closure of the river outlet, in response to particularly low water discharge, on the marine ecosystem and water quality. The modelling results covering a one-year simulation in this situation of closure indicate a deposition of 427,400 m3 of sediment in front of the mouth of the Oum-Errabia. Ensuring permanent river-mouth opening and tidal flushing and renewal of this river’s estuarine waters will necessitate costly regular dredging.

Seasonal variations of sediment load related to all large damming in the Red River system: A 64‐year analysis

AbstractVariations of water discharge and sediment load in the Red River basin have received considerable attention due to its drastic reduction during the past several decades. This paper presents a more specifically investigating of the seasonal variations in water discharge and sediment load from 1958 to 2021, both before and after the impoundment of all large dam‐reservoirs, using daily observations from the Son Tay hydrological gauging station, the outlet of the Red River system and entry to the delta. Sediment loads have decreased progressively since the early 1990s due to sediment yield reduction and dams in the upper basin, with a reduction of about 91% (from 116 × 106 to 11 × 106 t/year) over the 64‐year observation period. Prior to the impoundment of the Hoa Binh dam‐reservoir in 1988, the hydrological processes in the Red River system exhibited seasonal anomalies (clockwise mode on the hysteresis of rating curve), which implies that sediment load is highly proportional to water discharge and precipitation. The hysteresis loops between mean monthly water discharge and suspended sediment concentration after 1988 were altered by tributary dam‐reservoirs and a phenomenon known as ‘temporal monsoon moving’, which shifted the rating curve from clockwise to counterclockwise mode. Our long‐term analysis indicates that approximately 57.5% and 79% of sediments were trapped during the periods 1989–2008 (after Hoa Binh dam‐reservoir impoundment) and 2009–2021 (a series of new dam‐reservoirs went into operation), respectively, primarily during the high‐discharge months (June–October). Additionally, we concluded that the contribution of climate components (e.g., rainfall) to the dramatic decline in sediment load of the Red River system was less than the human impact.

Water discharge variations control fluvial stratigraphic architecture in the Middle Eocene Escanilla formation, Spain

Ancient fluvial deposits typically display repetitive changes in their depositional architecture such as alternating intervals of coarse-grained highly amalgamated (HA), laterally-stacked, channel bodies, and finer-grained less amalgamated (LA), vertically-stacked, channels encased in floodplain deposits. Such patterns are usually ascribed to slower, respectively higher, rates of base level rise (accommodation). However, “upstream” factors such as water discharge and sediment flux also play a potential role in determining stratigraphic architecture, yet this possibility has never been tested despite the recent advances in the field of palaeohydraulic reconstructions from fluvial accumulations. Here, we chronicle riverbed gradient evolution within three Middle Eocene (~ 40 Ma) fluvial HA-LA sequences in the Escanilla Formation in the south-Pyrenean foreland basin. This work documents, for the first time in a fossil fluvial system, how the ancient riverbed systematically evolved from lower slopes in coarser-grained HA intervals, and higher slopes in finer-grained LA intervals, suggesting that bed slope changes were determined primarily by climate-controlled water discharge variations rather than base level changes as often hypothesized. This highlights the important connection between climate and landscape evolution and has fundamental implications for our ability to reconstruct ancient hydroclimates from the interpretation of fluvial sedimentary sequences.

Analisis Daya Elektrik dan Efisiensi dengan Variasi Debit Air dan Sudut Kemiringan Turbin pada Turbin Ulir Archimedes Dua Sudu

This study analyzes the effect of water discharge and the angle of inclination of the turbine on electrical power and efficiency using Archimedes screw turbine with two blades. This study aims to determine the effect of water discharge and the angle of inclination of the turbine on the electrical power and efficiency of the two-blade Archimedes screw turbine. The turbine is fed with water at variations of water discharge of 150 l/m, 300 l/m, 450 l/m. And vary angle of inclination of the turbine of 35°, 40°, and 45°. By using the variation of the water discharge that has been mentioned, the electrical power and efficiency obtained are 1,24 W and 9,78 % at a variation of 150 l/m, 2,89 W and 10,77 % at a variation of 300 l/m, and 3,65 W and 9,06 % at a variation of 450 l/m. When varying the angle of inclination, the electrical power and efficiency obtained are 3,33 W and 10,77 % on a slope of 35°, 3,65 W and 10,53 % on a slope of 40°, and 3,15 W and 8,6 % on a variation of 45°.

Secular trend in water discharge transport in the Lower Mekong River-delta: Effects of multiple anthropogenic stressors, rainfall, and tropical cyclones

The Mekong River is one of the world's most important continental rivers, and provides invaluable water resources for the survival and social development of nearly 70 million inhabitants of Southeast Asia. However, little work has been carried out on the multiforcing-induced hydrological behavior of the Lower Mekong River-delta (LMR) over the past 100 years. Here, the secular variations in water discharge were analyzed for seven gauging stations along the main stream of the LMR from the 1920s-2019, to identify the riverine hydrological mechanisms under different dynamic conditions. The results show that the water discharge delivered by the LMR to the delta decreased on both 50-year and centennial scales. Meanwhile, the daily water discharge of the LMR-delta has become more evenly distributed intra-annually, leading to “no flood in the flood season, no drought in the dry season” in this reach. While regional rainfall dominates the long-term variations in the water discharge in the LMR, episodic tropical cyclones can induce a gradual increase with enlarged spatial divergences in water discharge from the mountainous region to the delta by bringing heavy rainfall. Moreover, although the operation of the mega dams in the Upper Mekong Basin has significantly influenced the distribution of the downstream water discharge in the dry season, minor impacts can also be found in the wet season. The water consumption for irrigation was increased from the upstream to the downstream basin, which may contribute to the severe reduction in the downstream water discharge, even though typhoons induced much more runoff along the downstream reach. Considering future climate change in Southeast Asia with potential upward trends in anthropogenic stressors, it can be expected that the water discharge of the LMR-delta could worsen, and urgent countermeasures that address water resource management should be strongly considered by decision-makers in the affected countries of the Mekong River-delta.

Long-term variations in water discharge and sediment load of the Pearl River Estuary: Implications for sustainable development of the Greater Bay Area

The water discharge and sediment load have been increasingly altered by climate change and human activities in recent decades. For the Pearl River, however, long-term variations in the sediment regime, especially in the last decade, remain poorly known. Here we updated knowledge of the temporal trends in the sediment regime of the Pearl River at annual, seasonal and monthly time scales from the 1950s to 2020. Results show that the annual sediment load and suspended sediment concentration (SSC) exhibited drastically decreased, regardless of water discharge. Compared with previous studies, we also found that sediment load and SSC reached a conspicuous peak in the 1980s, and showed a significant decline starting in the 2000s and 1990s, respectively. In the last decade, however, water discharge and sediment load showed slightly increasing trends. At the seasonal scale, the wet-season water discharge displays a decreasing trend, while the dry-season water discharge is increasing. At the monthly scale, the flood seasons in the North and East Rivers typically occur one month earlier than that in the West River due to the different precipitation regimes. Precipitation was responsible for the long-term change of discharge, while human activities (e.g. dam construction and land use change) exerted different effects on the variations in sediment load among different periods. Changes in the sediment regime have exerted substantial influences on downstream channel morphology and saltwater intrusion in the Greater Bay Area. Our study proposes a watershed-based solution, and provides scientific guidelines for the sustainable development of the Greater Bay Area.

Proglacial river sediment fluxes in the southeastern Tibetan Plateau: Mingyong Glacier in the Upper Mekong River

AbstractGlacial and proglacial erosion are important sediment sources in river basins. The retreat of many glaciers on the Tibetan Plateau has important implications on the supply of fresh water and sediment dynamics for downstream river basins. Despite the importance of water and sediment dynamics at these catchments, existing quantification of suspended sediment fluxes from glacial catchments on the Tibetan Plateau is limited due to poor accessibility and challenging environments. This study presents the results of in‐situ investigations of water discharge and suspended sediment fluxes from the Mingyong Glacier catchment in Yunnan, Southwest China, between August 2013 and July 2017. The results show that the variation in water discharge and suspended sediment was highly seasonal. The variation of average suspended sediment concentration was large—69 ± 45; 119 ± 104; and 94 ± 97 mg/L in 2013, 2015, and 2016, respectively. We estimate that the sediment yield from the Mingyong catchment was highly variable ranging from 1104 t/km2/year in 2013 to 2281 t/km2/year in 2016, with 65%–78% of the total annual sediment load occurring during the summer (June to August). These annual variations in sediment yield can be attributed largely to precipitation patterns and extreme melting events. This study has provided a benchmark dataset that can be used for further works that investigate the impact of climate change on sediment dynamics in glacierized catchments in the Tibetan Plateau. Subsequently, the study helps us to better understand the increasing sediment supply to the Upper Mekong River from glacierized headwater catchments.

Quantifying sediment retention by high-density small water conservancy facilities under insignificant variation of water discharge in the Nanliu River Basin, Beibu Gulf

Study regionThe Nanliu River Basin in Beibu Gulf, China. Study focusThe variations in water discharge and sediment load were analysed for 1961–2015. In addition, sediment retention by high-density small water conservancy facilities in the tributaries was estimated by a hydrological model with different scenarios. At the end of the study, the variation in the relationship between water discharge and suspended sediment concentration (SSC) and the impact on riverbeds were analysed. New hydrological insights for the regionThe sediment load showed a dramatically decreasing trend, and an abrupt change point in 1988 was detected by a Mann–Kendall test. Compared to the baseline period (1961–1988), the sediment load in the altered period (1989–2015) decreased by 41.7%. By employing the SWAT model with different scenarios, sediment retention by high-density small water conservancy facilities in the tributaries was estimated in the basin, with a mean value of 457.1 × 103 tons/yr during the altered period. The construction of water conservancy facilities has been the key driver of the significant reduction in sediment load observed in the Nanliu River. The rating curves of monthly SSC–discharge showed clockwise patterns, which were different from the Yangtze River’s counter-clockwise pattern. SSC reductions and excessive sand mining in the main channel have strongly affected riverbeds, leading to a year-by-year drop.

Pengaruh Variasi Sudut Kemiringan Dan Debit Air Terhadap Daya Dan Efisiensi Turbin Air Vortex

&lt;p&gt;&lt;em&gt;The vortex turbine is a moving turbine using artificial whirlpools that will then be converted into alternate energy turbines on the axis. The purpose of this study is to find out how high the Angle of skeleton tilt and dissipation of water affects the electricity and efficiency generated by vortex's water turbines. This study is using experimental methods. The study involves a few steps by preparing water turbines, sets up tools, data retrieval, and data analysis. The research free variable is a variant of the Angle of the skeletal tilt at 0, 5, 10 and a discharge of water at 6.34 l/s, 7.41 l/s, and 8.29 l/s. The bound variables of research are vortex's type of electric power and electricity efficiency. The research control variable is vortex turbine blade and vortex water turbine. The research instrument used is multimeter-based arduino, flowmeter-based arduino, tachometer, bow and digital balance. Data analysis techniques using quantitative descriptive analysis. The test conducted based on variations of water discharge at 6.34 l/s, 7.41 l/s, and 8.29 l/s and skeletal variant turbine gradient at 0, 5, and 10 of the power and efficiency of the turbines generated. Research shows that the maximum data of electrical calculation is obtained on water-discharge at 8.29 l/s with a tilted point 10 which was 10.3 watts, while the maximum efficiency data is obtained on water-diacharge at 8.29 l/s with a tilted point 10 which was 42.9%.&lt;/em&gt;&lt;/p&gt;

Anthropogenic pressures induced hydromorphodynamic changes of riverine islands in the Upper Jingjiang reach along the Changjiang (Yangtze) River

Riverine islands are widespread fluvial landforms with exceptional economic and environmental values. However, anthropogenic pressures have further induced drastic changes worldwide in fluvial islands, which endanger fluvial organism habitation and enable potential ecological degradation. Here, the hydromorphodynamics on these prominent riverine landforms of the seriously regulated Upper Jinjiang reach (UJR) of the Changjiang (Yangtze) River were detected based on the Google Earth Engine (GEE) platform between 1988 and 2019. The results indicated that total vegetated islands area in the UJR experienced expansion, while bars area exhibited a dramatic decrease by 15% between 1988 and 2019. Given the total areas and their subaquatic bars' volume variations, the island's evolution could be divided into “deposition–erosion–stabilization” stages. During the deposition phase from 1988 to 1999, the bars volumes showed a gradually increasing trend, and then it shifted to erosion between 1999 and 2010. After 2010, the islands maintained stability with a total volume of approximately 177 × 106 m3. The multi-year sediment and water discharge variations contributed to the evolution of riverine islands. In particular, resulting from the Three Gorges Dam (TGD) project in 2003, the fluvial sediment load and duration of overbank discharges (25000 m3/s) decreased significantly, which were the dominant factors inducing islands with their subaquatic bars shrinkage. Recent multiple island protection projects were responsible for defending islands with their subaquatic bars against erosion and maintaining their stability. This work reveals the islands' evolution in the UJR response to the TGD effect and local artificial engineering, which is vital for managing riverine islands in global rivers affected by nature and human activities.

Evolution patterns and spatial sources of water and sediment discharge over the last 70 years in the Yellow River, China: A case study in the Ningxia Reach

The hydrology and sediment processes in large rivers play important roles in maintaining aquatic and coastal ecosystems and advancing civilization and production in human systems. Therefore, quantitatively analyzing the spatiotemporal variability and dynamics of water and sediment discharge in large rivers is essential for improving watershed management and sustainable development in the areas surrounding rivers, especially the Yellow River, which is one of the most sediment-laden rivers in the world. In this study, we analyzed the evolution patterns and spatial sources of water and sediment discharge in the Yellow River from 1951 to 2020 and determined the impacts of different factors on water and sediment discharge variations. The results showed that the annual water and sediment discharge significantly decreased (p < 0.05) over the past 70 years, with an abrupt change occurring in 1986. The first dominant periodicity of water discharge was approximately 29 years, while the first dominant periodicity of sediment discharge was approximately 28 years. In terms of the water and sediment discharge sources, the dominant factor affecting variations in water discharge was water diversion from 1951 to 2020, while the dominant factor affecting variations in sediment discharge was sediment aggradation from 1951 to 1985 and changed to tributary inflow sediment from 1986 to 2020. In addition, the water and sediment discharge changes were also affected by anthropogenic activities, such as water and sediment diversions, dams and reservoirs, and water and soil conservation measures. In particular, the water and sediment interception capabilities of the established soil and water conservation measures gradually became saturated over time. Specifically, the maximum water and sediment interception capabilities of the current soil and water conservation measures were 12.2 billion m3 and 1.9 Gt, respectively. Overall, the results of the present study can help tailor water and sediment regulation countermeasures in the future.

Pengaruh Bentuk Penghalang Bervariasi Pada Proses Perpindahan Panas

Handling heat energy in the industrial world is very necessary. Heat exchangers have a fluid system that can be designed and developed using pipes. Heat transfer in a heat exchanger is a support for the performance of a heat exchanger to make it better. In this study, a heat exchanger was tested by placing a variety of barriers on the field of heat transfer flow and the addition of variations in the flow rate on the heat pipe. This test uses a aliran inch water flow pipe and a 2.5 inch iron tube pipe and a barrier material using aluminum. Based on the test results obtained a graph of varying heat transfer increases in each barrier. Differences in barrier variations and variations in water discharge greatly affect the value of heat transfer results. The purpose of this study was to look for the effectiveness and effect of adding a flow barrier to the performance of heat transfer in a heat exchanger.&#x0D; Keywords: Heat Exchanger, Effectiveness of Heat Transfer Heat

Variations in water discharge at different temporal scales in a mud-prone alluvial succession: The Paleocene-Eocene of the Tremp-Graus Basin, Spain

The late Paleocene to earliest Eocene sedimentary record in the eastern Tremp-Graus Basin (southern Pyrenees, Spain) consists of a mud-prone fluvial succession informally known as ‘Upper Red Garumnian’, which is dominantly composed of non-channelized deposits interspersed with fluvial channel bodies. The succession records evidence of variations in water discharge at multiple temporal scales. One-hundred-and-eighty sand-prone and conglomeratic bodies present within otherwise fine-grained deposits have been examined by facies and architectural-element analyses. These have been assigned to four distinctive types: (i) simple and (ii) compound channelized deposits, (iii) multilateral and multistorey elements, and (iv) sediment gravity-flow deposits. Simple and compound channel bodies represent deposits of channelized high-energy flows associated respectively with single floods or multiple events occurring in the same channel belt. Multilateral and multistorey elements are associated with sedimentation in longer-lived channel belts. An increase in the occurrence of these latter elements through the stratigraphy can be related to changes in tectonic and/or climatic drivers, heralding a change in facies architecture that signifies a shift to perennial discharge conditions and incised-valley backfilling. This is itself followed by a marked change in architectural style in a part of stratigraphy recording the Paleocene-Eocene Thermal Maximum (PETM), when variations in precipitation regime and/or intrabasinal characteristics (e.g., vegetation) related to this event favoured the lateral migration of channels, causing the development of laterally extensive coarse-grained bodies. Floodplain sediments comprise (i) heterolithic deposits accumulated in the vicinities of the fluvial channels where riparian ecosystems were developed, and (ii) overbank mudstones with variable degree of pedogenesis, especially associated with wetting and drying cycles in areas of the floodplain located distally away from fluvial channels. This succession records the importance of water-discharge variations in the evolution of alluvial systems: it displays facies arrangements recording the effects of highly variable discharge in ephemeral to perennial channels, as well as variations in stratigraphic architecture testifying to longer-term hydrological changes in the late Paleocene and earliest Eocene.

The Negro River in the Anavilhanas Archipelago: Streamflow and geomorphology of a complex anabranching system in the Amazon

AbstractThe evolution of the fluvial landscape is the result of controls and processes that can be observed by the adjustments a river makes to its hydrological regime. The Negro River is the sixth‐largest river in the world by water volume and contains two complex anabranching systems, the Anavilhanas and Mariuá archipelagos, and despite its importance, there is a lack of hydrological survey data on its multichannel reaches. The objective of this study was to analyse the fluvial dynamics of the lower Negro River and the morphodynamics of the Anavilhanas Archipelago channels in the Amazon basin. The analysed set of fluviometric surveys and cartographic data indicated that the average water velocity and depth of the channels were the most sensitive variables for water discharge variability. In addition, the reduction in the width/depth ratio of the channels in the Anavilhanas region is associated with an increased number of islands, but not with a fluvial transport capacity increase. These landforms play an important role in modulating flood wave dynamics in the lower reach of the Negro River. Seasonal water storage occurs in the channels and lakes of the archipelago due to the backwater effect caused by the Amazon River, which is the main control in the spatiotemporal variation of water discharge along the Anavilhanas Archipelago.

Tropical cyclone-induced water and suspended sediment discharge delivered by mountainous rivers into the Beibu Gulf, South China

Small mountainous rivers can deliver considerable freshwater discharge and suspended sediment discharge (SSD) to the ocean during tropical cyclones (TCs), and this has received special attention worldwide. However, little information is available on how TCs impact variations in water discharge and SSD delivered by mountainous rivers into the ocean. Here, based on the daily water discharge and SSD at the gauging stations of the tidal limit in July and August from 1965 to 2017, the Qin River (QR) and Nanliu River (NR), 2 small mountainous rivers located in the north of the Beibu Gulf, South China, were selected to quantify variations in water discharge and SSD into the Beibu Gulf during the TC period. The main results show that the net TC-induced water discharges in the QR and NR during July and August are larger than those of non-TC days, respectively. The net SSD increases in the QR and NR induced by TCs are far larger than those of normal days, respectively. Meanwhile, the water discharge and SSD in the flood season can be dominated by TC-associated rainfall, but the impacts on water discharge and SSD are influenced by the TC characteristics and basin environment. Moreover, it is found that in these 2 mountainous rivers, high water discharge delivers high SSD, but extremely high water discharge caused by TCs fails to produce extremely high SSD. It is expected that TCs will produce great impacts on SSD and water discharge of the mountainous rivers in South China behind global climatic change with increasing TCs events.

Методика краткосрочных прогнозов расходов воды на реках бассейна Камы на основе использования модели HBV

The experience of constructing a method for short-range forecasting of water discharge in the Kama River basin is described. The forecast method is based on the HBV-96 conceptual model of runoff formation in a watershed with optimized parameters, as well as on the algorithm for the correction of operational forecasts. It is shown that if the runoff formation model parameters are optimized and the forecast correction algorithm is applied, the model simulates variations in water discharge at gaging stations with high efficiency and can be used for operational short-range hydrological forecasting and for the evaluation of the hazard of expected hydrological conditions on the rivers. The implementation of the forecasting method allows obtaining water discharge forecasts for gaging stations in the Kama River basin with a lead time up to 3 days using meteorological forecasts with a corresponding lead time.