Upstream Flows Research Articles

A Coase Theoretic Approach to the Water Conflict between India and China

China is using Tibetan waters as an instrument for strengthening supremacy in the disputed territories. The country is often accused of harming its downstream neighbours through its water management policies, such as the construction of dams for hydropower. Moreover, China has no water treaties with the downstream countries. Only it shares limited data during the monsoon season on upstream flows. So, water conflict is there between China and neighbouring countries. Under such circumstances, conflict assessment is highly needed. Conflict assessment is the primary step in the process of conflict management and resolution. The present article suggests a Coase theoretic approach since Coase theorem is often used as a potential tool for conflict resolution.

Study on drainage strategy of ditch wetland in semi-arid area under the influence of inflow from the upstream irrigation area

Salt drainage from farmlands can potentially degrade the ecological function of ditch wetlands in arid and semi-arid irrigation areas. However, such ditch wetlands may accept different quantities and salt concentrations of upstream inflows, which may have positive or negative effects on the water and salt dynamics of ditch wetland systems and, therefore, on the associated water and salt management measures. In this paper, we propose a new theoretical analysis model that enables us to study the influence of different upstream inflows on the water–salt dynamics and drainage strategies for ditch wetland in the study area. The research carried out by us has revealed that upstream inflow is one of the most important factors influencing ditch wetlands under the current conditions. An increase in salinity or a decrease in flow will negatively affect the ecology of the ditch wetland. In contrast, which will improve the ditch wetland environment. Nevertheless, wetlands are more sensitive to changes in salinity than to the volume of upstream inflow. Based on the combined effects of the salinity and quantity of its inflow on the wetlands, it can be divided into four categories: no-risk, low-risk, medium-risk, and high-risk. The inflow with no risk and low risk will have a positive effect on the ditch wetland system and drainage management, while medium-risk and high-risk conditions will increase the difficulty of drainage management, These results provide the insights needed to guide the design of drainage management practices for ditch wetlands in semi-arid regions that receive upstream inflows to maximize the benefits to the agricultural system and the environment.

A numerical study of Hydro-Hydraulic energy on Undular Tidal Bore phenomenon

A preliminary study of hydro-hydraulic energy on undular bores may support the invention of various kinds of technology related to renewable energy sourced from the potential of natural resources of Indonesia. Energy could be generated from one type of hydraulic jump that occurs in the river channel, namely undular tidal bore. The tidal bore phenomenon also exists in Indonesia, which occurs in the Kampar River, Riau, known as Bono. A numerical study of energy on wave-like tidal bore has been done for one type of bores, namely undular bores. The simulation of undular bores has been generated using the Computational Fluid Dynamics (CFD) approach assisted by the open-source CFD software, OpenFOAM which applied a turbulent model, namely one-equation Large Eddy Simulation (LES). The undular bores simulation in this study has been validated using experimental and numerical data from selected scientific references. Six simulations of undular bores have been performed based on six different values of Froude number, Fr = 1.04, 1.13, 1.20, 1.27, 1.34, and 1.41. Furthermore, the free surface of undular bores simulation was analyzed by emphasizing on the depth of upstream and downstream flows (d0 and d2 respectively). The rate of change of flow depth ( ), energy dissipation ( ), the rate of energy dissipation ( ), and hydraulic power dissipated of undular bores (PUB ) will increase as a function of the Froude number.

Влияние климатических изменений на вертикальный влагообмен в почвах (на примере бассейна реки Волги)

The effect of climatic changes on surface and underground runoff cannot be explained without studying such changes on such processes of moisture transfer in soils as infiltration, evaporation, migration of moisture to the frost front. These processes are components of moisture exchange in soils and almost completely determine the mechanisms of runoff formation and its climatic interconformity. The paper discloses the main links of vertical moisture exchange in soils with environmental factors such as temperature, precipitation, wind speed and water vapor pressure. On the example of the Volga basin, changes in moisture flows in soils over the past decades are considered. Methods. To reveal the patterns of moisture exchange, a physically sound mathematical model of vertical heat-moisture transfer in soils and snow cover was used. Numerical experiments were carried out to assess the impact of all the main weather factors that cause long-term changes in vertical moisture flows in soils for the period 1952-2019. Results. Calculations showed that in the 1970s there were significant changes in soil moisture flows. There was a preferential increase in downstream flows and a decrease in upstream flows, which under certain weather conditions led to an increase in the level of groundwater. In recent decades, the growth of descending soil moisture flows in the river basin. Volga and, accordingly, groundwater levels have slowed down.

Assessment of the effects of human activity and natural condition on the outflow of Syr Darya River: A stepwise-cluster factorial analysis method

Water scarcity causes a series of eco-environmental problems, such as land salinization, biodiversity reduction and food crisis, which seriously restricts the sustainable development of the Aral Sea basin. In this study, a stepwise-cluster factorial analysis (SCFA) approach is proposed for assessing the effects of natural condition and human activity on the outflow of Syr Darya River (abbreviated as OSR) that has significant effects on the eco-environmental restoration of the Aral Sea. SCFA coupled stepwise cluster analysis and factorial analysis cannot only reflect the variability of outflow, but also identify the driving factors quantitatively. The results disclose that, in 1960–1991, the dominant factors (affecting the OSR) are upstream inflow (25.77%) > agricultural water use of Uzbekistan (7.21%) > industrial water use of Uzbekistan (4.53%) > agricultural water use of Kazakhstan (3.81%) > Precipitation (3.66%); interactions between upstream inflow and agricultural water use of Uzbekistan, Kazakhstan and Tajikistan and interactions between reservoir and evapotranspiration have the significant effects on the OSR. Results also indicate that, in 1992–2015, the dominant factors that affect the OSR are agricultural water use of Uzbekistan (23.31%) > agricultural water use of Kazakhstan (22.15%) > industrial water use of Uzbekistan (8.31%) > domestic water use of Kazakhstan (4.68%) > agricultural water use of Tajikistan (4.54%) > domestic water use of Uzbekistan (4.41%); the interactions between industrial water use and agricultural water use of Uzbekistan, Kazakhstan and Tajikistan and the interactions between reservoir and upstream inflow have the pivotal effects on OSR. In the future, when the agricultural water use of the basin decrease as 4% and the industry water use of Uzbekistan decrease as 2%, the OSR may recover to the middle level of 1970s. The results help identify the major factors affecting the outflow of Syr Darya River as well as seek an effective approach to restore the eco-environment of Aral Sea basin.

Fish Rescue during Streamflow Intermittency May Not Be Effective for Conservation of Rio Grande Silvery Minnow

Streamflow intermittency can reshape fish assemblages and present challenges to recovery of imperiled species. During streamflow intermittency, fish can be subjected to a variety of stressors, including exposure to crowding, high water temperatures, and low dissolved oxygen, resulting in sublethal effects or mortality. Rescue of fishes is often used as a conservation tool to mitigate the negative impacts of streamflow intermittency. The effectiveness of such actions is rarely evaluated. Here, we use multi-year water quality data collected from isolated pools during rescue of Rio Grande silvery minnow Hybognathus amarus, an endangered minnow. We examined seasonal and diel water quality patterns to determine if fishes are exposed to sublethal and critical water temperatures or dissolved oxygen concentrations during streamflow intermittency. Further, we determined survival of rescued Rio Grande silvery minnow for 3–5 weeks post-rescue. We found that isolated pool temperatures were much warmer (>40 °C in some pools) compared to upstream perennial flows, and had larger diel fluctuations, >10 °C compared to ~5 °C, and many pools had critically low dissolved oxygen concentrations. Survival of fish rescued from isolated pools during warmer months was <10%. Reactive conservation actions such as fish rescue are often costly, and in the case of Rio Grande silvery minnow, likely ineffective. Effective conservation of fishes threatened by streamflow intermittency should focus on restoring natural flow regimes that restore the natural processes under which fishes evolved.

Lessons from the Case History of a Massive Landslide Dam

A massive landslide created a natural dam on two tributaries of Jhelum River near the town of Hattian Bala in Kashmir in October 2005. The landslide was triggered by a 7.6 Mw earthquake. The resulting unconsolidated dam and water impoundment upstream carried hazard potential of downstream damage to both infrastructure and population due to potential flooding caused by its breach. Comprehensive investigations and monitoring were implemented to analyse dam stability. Fresh topographic profiles were generated. Samples of the matrix materials were utilized in the laboratory investigations including grain-size analysis, laboratory electrical resistivity and permeability tests at varying densities and degrees of saturation, and sediment concentration assessment in the seepage discharge. A noninvasive geophysical method was employed together with new topographic information to develop transient subsurface pictures and to assess the advancement of seepage fronts within the dam body. Internal erosion/filtering potential of the matrix material was assessed by comparing grain size distributions with those of the earlier failed dams. Upstream inflows, downstream discharges, daily precipitation, and lake levels monitored during the study period were utilized in hydrological data analysis in an attempt to assess the potential seepage volume. A combination of empirical, analytical, and numerical methods and simulations, together with laboratory and field investigations, led to the interpretations regarding short- and long-term stability of the dam. This paper highlights alternative methods of investigation employed differently from those used by other national and international agencies in analysing the failure potential of this natural dam. It offers lessons learned from a case history that can be beneficial in future evaluation of seepage-induced failure of similar natural features.

The Assessment of Hydrological Availability and the Payment for Ecosystem Services: A Pilot Study in a Brazilian Headwater Catchment

The assessment of water availability in river basins is at the top of the water security agenda. Historically, the assessment of stream flow discharge in Brazilian watersheds was relevant for dam dimensioning, flood control projects and irrigation systems. Nowadays, it plays an important role in the creation of sustainable management plans at the catchment scale aimed to help in establishing legal policies on water resources management and water security laws, namely, those related to the payment for environmental services related to clean water production. Headwater catchments are preferential targets of these policies and laws for their water quality. The general objective of this study was to evaluate water availability in first-order sub-basins of a Brazilian headwater catchment. The specific objectives were: (1) to assess the stream flow discharge of first-order headwater sub-basins and rank them accordingly; (2) to analyze the feasibility of payment for environmental services related to water production in these sub-basins. The discharge flow measurements were conducted during five years (2012 to 2016), in headwaters in a watershed on the São Domingos River at the Turvo/Grande Watershed, represented as the 4th-largest hydrographic unit for water resources management—UGRHI-15 in São Paulo State, Brazil. A doppler velocity technology was used to remotely measure open-channel flow and to collect the data. The discharge values were obtained on periodic measurements, at the beginning of each month. The results were subject to descriptive statistics that analyzed the temporal and spatial data related to sub-basins morphometric characteristics. The discharge flows showed space–time variations in magnitude between studied headwater sub-basins on water availability, assessed based on average net discharges. The set of ecological processes supported by forests are fundamental in controlling and recharging aquifers and preserving the volume of water in headwater in each sub-basin. The upstream inflows influence downstream sub-basins. To avoid scarcity, the headwater rivers located in the upstream sub-basins must not consider basin area as a single and homogeneous unit, because that may be the source of water conflicts. Understanding this relationship in response to conservationist practices installed uphill influenced by anthropic actions is crucial for water security assessment. The headwaters should be considered a great potential for ecosystem services, with respect to the “provider-receiver” principle, in the context of payments for environmental services (PES).

Channel hydrological response function considering inflow conditions and hydraulic characteristics

To bypass the problem of numerical instability in conducting the channel routing system, the application of an impulse response function based on the linearization of Saint Venant equations has been an alternative for predicting streamflow discharge. However, the distribution type of the impulse response function proposed by Dooge et al. (1987a) is restricted during a flood, so this approach cannot adequately describe flow response in practical applications. In considering that the flow response in a natural channel is usually influenced by the shape of the cross-section, the terrain of channel bed and the discharge of the moving flood, this study focuses on improving the original unit impulse function by conducting two aspects of analysis: (1) the distribution of unit impulse response function was changed with time by adjusting the reference parameters according to the inflow condition and the hydraulic variables; (2) the outcome of this modified linear approach was thoroughly examined by comparing the simulated results with that adopting the original linear channel method and the numerical scheme based on the nonlinear Saint Venant equations. Moreover, for achieving the simulation of a whole river basin, a complete executing procedure was provided to explain the connection between the upstream inflows, lateral flows, and the linear channel response of each channel reach. A series of tests showed that the proposed method can produce approximated hydrographs in comparison with numerical simulation results owing to the flexibility of the impulse response function although the linear channel routing adopts simplified mathematical operations. A case study of a natural river basin also demonstrated the applicability of the modified channel response system.

Applicability of Kinematic Wave Model for Flood Routing under Unsteady Inflow

This study implemented kinematic wave and dynamic wave approximation of flood routing for a prismatic rectangular channel. The results of the two methods were compared by differences in maximum flow depth, and the applicability of kinematic wave equation was discussed. The influences of hydraulic and geometrical factors on the applicability of kinematic wave equation were considered. It was found that a portion of the numerical results violated existing criteria used to indicate the applicability of kinematic wave equation, particularly when geometrical and hydraulic factors were considered together. This is because the characteristics of upstream inflow were rarely or incompletely considered in these criteria. Therefore, the present study proposed a new criterion. The theoretical influence of all factors was considered using three parameters, namely, KF02, ηts/T0′ and Qbottom/Qpeak (K, F0, ηts, T0′, Qbottom, and Qpeak represent the kinematic wave number, Froude number, the time span of discharge exceeding 90% of maximum discharge in hydrograph, wave travel time in the channel, base flow discharge, and peak discharge, respectively, while the subscript 0 represent the value of reference discharge). The influences of these three parameters were illustrated by the momentum equation of one-dimensional Saint-Venant equation. The numerical results showed that the value of ηts/T0′ (KF02)D could be used to determine the relative error ξh of kinematic wave equation. In addition, for each Qbottom/Qpeak the value of ηts/T0′ (KF02)D used to depict the same relative error ξh was different. This new criterion was validated using two real case studies, and it showed a good performance.

Virtual Tracers to Detect Sources of Water and Track Water Reuse across a River Basin

Water managers around the world face the increasingly challenging task to evaluate the impacts of technological measures and policy mechanisms from the local to the river basin scale. A toolset providing quantitative, actionable information on dependencies and trade-offs between upstream and downstream water users is currently lacking. Yet, any intervention needs to be assessed in terms of consequences for downstream water users. This study evaluates the potential of a tracer-like approach, implemented in the water allocation software WEAP, to quantitatively track return flows and their downstream reuse in the river basin context. The WEAP-Virtual Tracer (WEAP-VT) approach was successfully applied to one of Europe’s driest river basins, the Segura River Basin in Spain. For each water demand site, the different original sources of water supply, dependency on upstream return flows, and downstream reuse of its return flow were assessed. Based on these results, agricultural, urban, and environmental water users were evaluated in terms of their suitability for water saving measures and their vulnerability to the reduction in upstream return flows. A scenario analysis simulating the improvement of local efficiency improvements shows that specific irrigation schemes and ecosystems become deprived of water. Hence, efficiency improvement in water-scarce basins should be considered with caution. The demonstrated ability to quantify key water reuse indicators for individual water users and at different aggregation levels makes WEAP-VT a valuable tool to support water resource management decisions.

Supply Chain Risk Governance: Towards a Conceptual Multi-Level Framework

The coronavirus pandemic (COVID-19) is currently putting high pressure on most countries’ critical infrastructures (not only health care), creating huge uncertainties in supply and demand, and disrupting global supply chains. The global crisis will demonstrate the extent to which different parties (countries, public authorities, private companies etc.) can work together and take holistic decisions in such situations. A core question in supply chain management asks how independent decision-makers at many levels can work together and how this joint work can be governed. Supply chain risk management (SCRM), however, has focused mostly on how focal private companies apply SCRM processes to identify, analyse and mitigate risk related to upstream and downstream flows in their supply networks. At the same time, interorganisational collaboration to handle diverse risks is always needed. A risk that hits one organisation often affects other, interconnected organisations. This study aims to develop the term supply chain risk governance with an associated conceptual framework that embraces various types of supply chains and actors. In a cross-disciplinary literature study, we dissect, compare and combine risk governance with interorganisational aspects of SCRM and find that the mechanisms suggested in the risk governance literature coincide with many of those in SCRM. We suggest a combination of these to govern risk processes at an inter-organisational level, regardless of the type of organisation included in the supply chain. This would be suitable for critical infrastructures that often contain a mixture of private and public actors. The scope of the literature employed is limited, and some articles have played a larger role in the framework development. The paper explores new territory through this cross-disciplinary study, extends existing multi-level frameworks with inter-organisational governance mechanisms and proposes new governance mechanisms to the field. This study could support the understanding of how critical infrastructures in our society are governed so as to increase their resilience to both smaller and larger disruptions. (Less)

Magnetic dissipation of near-wall turbulent coherent structures in magnetohydrodynamic pipe flows.

Relaminarization of wall-bounded turbulent flows by means of external static magnetic fields is a long-known phenomenon in the physics of electrically conducting fluids at low magnetic Reynolds numbers. Despite the large literature on the subject, it is not yet completely clear what combination of the Hartmann (M) and the Reynolds number has to be used to predict the laminar-turbulent transition in channel or pipe flows fed by upstream turbulent flows free of magnetic perturbations. Relying upon standard phenomenological approaches related to mixing length and structural concepts, we put forward that M/R_{τ}, where R_{τ} is the friction Reynolds number, is the appropriate controlling parameter for relaminarization, a proposal which finds good support from available experimental data.

Assessment of Flood Risk Exposure for the Foshan-Zhongshan Region in Guangdong Province, China

Floods have caused 20% of the worldwide economic losses resulting from catastrophe events over 2008 to 2018. In China, the annual flood economic losses have exceeded CNY 100 billion from 1990 to 2010, which is equivalent to 1% to 3% of China’s Gross Domestic Product (GDP). This paper presents a rainfall-runoff model coupled with an inundation estimation to assess the flood risk for a basin within the Foshan-Zhongshan area of the Pearl River Delta (PRD) region in China. A Hydrologic Engineering Center’s Hydrologic Modeling System (HEC-HMS) model was constructed for the crisscrossing river network in the study basin where the West and North Rivers meet, using publicly accessible meteorological, hydrological and topographical datasets. The developed model was used to analyze two recent flood events, that in July 2017 with large upstream river inflows, and in June 2018 with high local rainfall. Results were further used to develop the needed river rating curves within the basin. Two synthetic events that consider more severe meteorological and hydrological conditions were also analyzed. These results demonstrate the capability of the proposed model for quick assessment of potential flood inundation and the GDP exposure at risk within the economically important PRD region.

An Adaptive Surrogate Assisted CE-QUAL-W2 Model Embedded in Hybrid NSGA-II_ AMOSA Algorithm for Reservoir Water Quality and Quantity Management

The Meimeh dam construction is a project, planned to provide sustainable livelihoods, social, and economic developments in the Meimeh River Basin, Ilam, Iran. However, due to the high concentration of TDS in the Meimeh River and its tributaries, river impoundment and water storage can be harmful to the Meimeh Reservoir. The upstream inflow control and the reservoir operation management in a selective withdrawal scheme (SWS) were used to mitigate the potential environmental degradation of Meimeh Reservoir’s low water quality. CE-QUAL-W2 and WEAP (Water Evaluation and Assessment Programming) models were employed to evaluate the effects of various upstream saline inflow control scenarios. The analysis indicated that the diversion of the Siyoul tributary flow rate in the Meimeh River could result in lower violations of Total Dissolved Solids (TDS) concentrations and better water supply satisfaction. Then, the optimal reservoir operation management strategies in a SWS were derived in the best upstream inflow control scenario. The adaptive surrogate-assisted WQSM (water quality simulation model), coupled to hybrid NSGA-II_AMOSA (Non-dominated Sorting Genetic Algorithm-II_Archived Multi-Objective Simulated Annealing) algorithm, has been applied to derive the suitable reservoir operation strategies in SWS, improve the water supply satisfaction and alleviate the adverse effects of reservoir outflow TDS violations. The performances of the best water quality and supply scenarios have been compared with the scenario based on the standard operation policy (SOP) in the Meimeh Reservoir. The results show that most violations of TDS criteria occur during the peak agricultural seasons and significant water deficit in some dry years happens in the SOP.

The effect of a strong density step on blocked stratified flow over topography

The dynamical connection between topographic control and wave excitation aloft is investigated theoretically and numerically in the idealized setting of two-dimensional stratified flow over an isolated ridge. We consider a constant far upstream inflow with uniform stratification except for a sharp density step located above the height of the ridge crest. Below this step, the stratification is sufficiently strong that the low level flow is blocked upstream and a hydraulically controlled flow spills over the crest. Above the density step, the flow supports upward radiating waves. In the inviscid limit, a bifurcating isopycnal separates the hydraulically controlled overflow from the wave field aloft. We show that, depending on the height of the density step, the sharp interface can either remain approximately flat, above the controlled downslope flow, or plunge in the lee of the obstacle as part of the controlled overflow itself. Whether the interface plunges or not is a direct consequence of hydraulic control at the crest. The flow above the crest responds to the top of the sharp density step as if it were a virtual topography. We find that a plunging interface can excite a wave field aloft that is approximately six times as energetic, with 15 % higher pressure drag, than that in a comparable flow in which the interface remains approximately flat.

Numerical estimation of prototype hydraulic efficiency in a low head power station based on gross head conditions

Low-head hydraulic power units typically have a short intake pipe or no that structure. For this reason, the upstream and downstream flows in reservoirs could influence the internal flow characteristics in the turbine, which sometimes increase the flow non-uniformity and the local hydraulic losses. Meanwhile, the efficiency estimation methods for prototype turbines still have a limitation for determining the unit discharge, which is generally predicted by using a Winter-Kennedy method. This paper proposes a hydraulic performance estimating method focusing on low-head turbine units, which is conducted by using CFD analysis and based on site test results. A bulb type turbine unit was adopted as a research object, which is operating in a low-head run-of-the-river power station. The flow behaviors in turbine were simulated based on two water levels under single unit operation, with two reservoir modeling. The simulation results agreed well with test ones for the turbine power as well as the relative discharge curve. The prototype efficiency in operation was estimated at the same time. In addition, this paper analyzed the relationship between the gross head and net head, and introduced the concept of plant hydraulic efficiency, as regards the flow interaction between the turbine unit, intake and tailrace.

Climate Change Impacts on Reservoir Inflow in the Prairie Pothole Region: A Watershed Model Analysis

The Prairie Pothole Region (PPR) is known for its hydrologically complex landscape with a large number of pothole wetlands. However, most watershed-scale hydrologic models that are applied in this region are incapable of representing the dynamic nature of contributing area and fill-spill processes affected by pothole wetlands. The inability to simulate these processes represents a critical limitation for operators and flood forecasters and may hinder the management of large reservoirs. We used a modified version of the soil water assessment tool (SWAT) model capable of simulating the dynamics of variable contributing areas and fill-spill processes to assess the impact of climate change on upstream inflows into the Shellmouth reservoir (also called Lake of the Prairie), which is an important reservoir built to provide multiple purposes, including flood and drought mitigation. We calibrated our modified SWAT model at a daily time step using SUFI-2 algorithm within SWAT-CUP for the period 1991–2000 and validated for 2005–2014, which gave acceptable performance statistics for both the calibration (KGE = 0.70, PBIAS = −13.5) and validation (KGE = 0.70, PBIAS = 21.5) periods. We then forced the calibrated model with future climate projections using representative concentration pathways (RCPs; 4.5, 8.5) for the near (2011–2040) and middle futures (2041–2070) of multiple regional climate models (RCMs). Our modeling results suggest that climate change will lead to a two-fold increase in winter streamflow, a slight increase in summer flow, and decrease spring peak flows into the Shellmouth reservoir. Investigating the impact of climate change on the operation of the Shellmouth reservoir is critically important because climate change could present significant challenges to the operation and management of the reservoir.

A new program for the hydraulic calculation of steam-water mixture pipelines in geothermal fields

A new mathematical model of steam-water flow in a pipeline, which takes into account the gravitational effect and satisfies new challenges in the development of geothermal fields with two-phase transportation of the heat carrier is presented. Taking into account the gravitational effect in the upstream flows, a method based on the “drift model”, which determines the steam velocity averaged over the crosssection was used. A similar method is proposed for downstream flows, but it determines the water velocity averaged over the cross-section. In this case, analogs of empirical coefficients were used. These coefficients determined from the condition of equality of parameters calculated using different approaches in a horizontal flow. The model was verified, which showed positive results. The proposed model significantly expands the possibilities of hydraulic calculation of steam-water mixture pipelines in geothermal fields.

Characterizing the Hydraulic Connection of Cascade Reservoirs for Short-Term Generation Dispatching via Gaussian Process Regression

The characterization of the mapping relationship (MR) between outflow of the upstream reservoir (OUR) and inflow of the downstream reservoir (IDR) in the short-term generation dispatching of cascade reservoirs (SGDCR) greatly impacts the safe and economic operation of hydropower plants. If this MR is not characterized properly, the operation process of hydropower stations will deviate from the planning dispatching schemes. Especially when the upstream reservoir (UR) undertakes peak load regulation tasks frequently and the downstream reservoir (DR) owns weak re-regulation capacity, the safety of cascade reservoirs will be seriously threatened. In this extreme system, the commonest characterizing models in SGDCR, such as the lag time (LT) model and the Muskingum model, may cause a huge deviation when simulating or forecasting the IDR. Given this dilemma, the Gaussian process regression (GPR) model, which is a representative for Bayesian regression methods, is firstly introduced to handle this MR and compared with the LT and the Muskingum model in this paper. The Three Gorges-Gezhouba cascade reservoirs (TGGCR) in China are selected as a typical case study. The performance indicators of four categories are adopted to evaluate the simulated IDR in a single period and a set of pivotal indicators are proposed to estimate the simulation dispatching in multiple periods. The results show that (1) The GPR model reduces the mean absolute deviation (MAD) about inflow of Gezhouba by 197m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> /s and 263m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> /s than the LT and the Muskingum model respectively; (2) The distribution characteristics of inflow deviation produced by the GPR model are most competitive. Meanwhile, the GPR model has the strongest ability when conducting the multi-period simulation dispatching and owns best applicability on the whole range of streamflow. (3) The Muskingum model is not recommended to characterize the hour-scale hydraulic connection in the extreme system of SGDCR.