Model Of Runoff Formation Research Articles

Brief review of the monograph assessment of long-term runoff in the southwestern part of the African continent (scenarios of long-term changes in probability characteristics)

For the physical and geographical conditions of the African continent, it is more acceptable to simplify the runoff formation model by adapting to the relatively poorly studied long-term river flow regime of North Africa. The solution to the problems is based on the methodology of partially infinite modeling, developed in Russia and used in countries of Latin America and Africa with hot climates.

СВЕРХДОЛГОСРОЧНЫЙ ПРОГНОЗ СТОКА РЕК РОССИИ

The possibility of extended predictions of the Russian river streamflow is considered based on dynamic approach, in which the HBV-96 water-balance runoff formation model is used jointly with the extended ensemble meteorological forecast obtained with the INM5 model. Twelve river basins located in different climatic and physiographic zones of Russia were selected for analysis. The average annual and average monthly discharges, as well as the annual maximum streamflow, were predicted with a lead time of 1-5 years. The test on the reanalysis data for the period from 1980 to 2020 has shown that the applied dynamic approach makes it possible to adequately assess possible interannual fluctuations in the streamflow and its intraannual distribution. The ensemble of forecasts of the annual and maximum streamflow for the period 2023-2026 obtained using the HBV-96 and INM5 models is consistent with the data on the water regime of the analyzed rivers.

Simulating Runoff Regime in a Glaciated High-Mountainous Basin: A Case Study of the Baksan River (Caucasus, Russia)

The water resources of the North Caucasus depend mostly on the state of glaciers, which have been intensely losing their mass in the recent decades against the background of climate changes. The deglaciation leads not only to a decrease in the glacier runoff of mountain rivers, but also to changes in the annual distribution of runoff. The focus of this study is the adaptation of ECOMAG software complex to simulating river runoff in the Baksan River basin based on data on the relief and underlying surface of the drainage basin (soil, vegetation) and daily data on the surface air temperature, air saturation deficit, and precipitation. The calibration and validation of the model and the statistical estimate of calculation efficiency were based on the data on water discharges in the Baksan River over 2000–2017. The developed model of runoff formation in the Baksan River basin was used to carry out numerical experiments for assessing the sensitivity of runoff characteristics to glacier area variations. Depending on the rate of deglaciation process, the runoff of the Baksan River can drop by 10–30% because of a decrease in its glacial component, and the maximal water discharges can drop by 10–15%.

Evaluating Inundation Characteristics under Climate Changes

A procedure of hydrodynamic modeling of floodplain inundation characteristics is presented; the procedure takes into account climate change scenarios and is based on the results of numerical experiments with river runoff formation model and the results of ensemble calculations by global climate models. The model calculations were based on Russian software systems ECOMAG and STREAM_2D. For the key segment of the Lena at Yakutsk C. (Tabaga gage), the calculations by all scenarios and models show a possible increase in the runoff by the mid-XXI century along with an increase in the inundation areas and depths by 9–15% due to the increase in runoff.

Methodology for Calculating Daily Streamflow of Russian Rivers Using the HBV-96 Runoff Formation Model

Methodology for Calculating Daily Streamflow of Russian Rivers Using the HBV-96 Runoff Formation Model

Методики краткосрочного прогнозирования стока рек бассейна Камы

For the rivers of the Kama basin, two methods have been developed for daily short-term forecasting of average daily water discharges with a lead time of 1, 2, and 3 days. The first technique uses the HBV-96 river runoff formation conceptual model and the subsequent correction of forecasts outputs. The second technique is based on the hydrograph extrapolation method and is limited to the data of hydrological observations available by the date of the forecast. For the first technique, the expected values of the COSMO-Ru meteorological model temperature and precipitation forecasts are used for the lead-time period of the hydrological forecast. The influence of meteorological forecast errors on the accuracy of river streamflow forecasts was analyzed. The results of the verification based on an independent sample showed that, in general, both methods give a satisfactory forecast quality. The technique that uses the runoff formation model and meteorological information is slightly more accurate than the hydrograph extrapolation method, and its advantage increases with increasing forecast lead time. Keywords: Kama basin, water discharge, hydrological model, correction, extrapolation, verification, forecast quality

SOME QUESTIONS OF ESTIMATING SUSPENDED SEDIMENT IN WATERCOURSES OF NORTH-WEST RUSSIA

In the practice of water management for economic purposes, calculations of suspended sediment for various time scales – from per-second to annual, are important. The estimation of annual suspended sediment transport, as well as of the statistical parameters of turbidity and the reliability of the estimates, is extremely difficult because of irregular and insufficient light conditions in different phases of the water regime. At the same time, owing to the knowledge of the processes that shape the quality of natural waters and a sufficient toolkit of calculation methods, the main indicators of water quality with can be reproduced with acceptable accuracy. The capabilities of statistical analysis of water quality indicators can be expanded by an integrated approach to estimating the indicators by means of well-proven deterministic and stochastic calculation algorithms with arguments observed regularly and for a long time. In this case, a composite method can be used to estimate the parameters of the suspended sediment distribution or water turbidity, which permits finding the parameters of the distribution curve of the function from the parameters of the distribution curve of its arguments. The paper presents a deterministic-stochastic modeling system “weather-runoff-suspended sediments”, based on a stochastic weather model, a model of runoff formation in a catchment area, and a model of annual suspended sediment transport. The system can estimate the distribution parameters of daily suspended sediment load and turbidity values in the situation of observed data shortage or changes in runoff formation in the catchment resulting from natural causes or economic activities.

Modelling of future changes in the water regime of the Upper Kama River

Calculations of future changes in the water regime for the Kama reservoir basin were carried out based on the ECOMAG regional semi-distributed runoff formation model and data from an ensemble of four atmosphere-ocean general circulation models using the RCP2.6 and RCP6.0 scenarios. Estimates of changes in the runoff of the Upper Kama River are presented for the middle and end of the 21st century relative to the historical period 1986 – 2005. The downward trend in both annual and summer water inflow into the Kama reservoir will continue in the future, despite an increase in winter runoff. Moreover, the decrease in runoff will be more significant under the RCP6.0 scenario. Despite the increase in precipitation up to 10%, the decrease in the annual runoff of the Upper Kama River will be from 4% to 17% due to intense warming in the catchment area by 2–5°C, depending on the season of the year, the period of the 21st century and the RCP scenario.

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.

Modeling of Extreme Hydrological Events in the Baksan River Basin, the Central Caucasus, Russia

High mountain areas are prone to extreme hydrological events, and their study is especially important in the context of ongoing intensive deglaciation. In this research, a model “chain” consisting of a hydrodynamic model and a runoff formation model is adopted to simulate a glacier lake outburst flood (GLOF) from Bashkara Lake (the Central Caucasus, Russia) and its effect on downstream. In addition to an actual GLOF event that occurred on 1 September 2017 and led to casualties and significant destruction in the Adylsu and Baksan Rivers valleys, possible scenarios for the re-outburst of the lake are considered. The hydrographs of the outburst and the downstream movement of the flood wave along the Adylsu River valley are estimated using STREAM_2D two-dimensional hydrodynamic model. The water discharges in the entire river network of the Baksan River are assessed using the ECOMAG (ECOlogical Model for Applied Geophysics) runoff formation model. The output flood hydrograph from the hydrodynamic model is set as additional input into the Baksan River runoff formation model in the upper reaches of the Adylsu River. As a result of the simulations, estimates for the contribution of GLOFs and precipitation to an increase in peak discharge along the Baksan River were obtained. The actual outburst flood contributed 45% and precipitation 30% to the peak flow in the Baksan River at the mouth of the Adylsu River (10 km from the outburst site). In Tyrnyauz (40 km from the outburst site), the contributions of the outburst flood and precipitation were equal and, in Zayukovo (70 km from the outburst site), the outburst flood contributed only 20% to the peak flow, whereas precipitation contributed 44%. Similar calculations were made for future potential re-outburst flood, taking into account climatic changes with an increase in air temperatures of 2 °C, an increase in precipitation of 10% in winter and a decrease of 10% in summer. The maximum discharge of the re-outburst flood in the Adylsu River mouth, according to model estimations, will be approximately three times less than the discharge of the actual outburst on 1 September 2017 and can contribute up to 18% of the peak discharge in the Baksan River at the confluence.

Perspectives of the development of complex interdisciplinary hydrological and geocryological research in the North-East of Russia

Climate warming and anthropogenic impact causes transformation of geocryological conditions in the river basins of the North-East of Russia. Changes in the thickness of the active layer, configuration of taliks, types of landscapes and other factors lead to transformation of water exchange processes between surface and groundwater runoff. This is manifested in the seasonal redistribution of the components of the water balance, accelerated melting of aufeis, change in the ratio of waters of different genesis in the structure of river runoff. As a result, natural and anthropogenic risks that affect the safe and efficient development of infrastructure and socio-economic processes are increasing. At the same time the system of observations developed in the Soviet period has been practically destroyed in the region. This paper offers a vision of organizing complex multidisciplinary research to assess and project the changes in the conditions of underground and surface water interaction in natural and disturbed river basins of the cryolithozone of the North-East of Russia, including for solving applied problems, based on permafrost, hydrology, hydrogeology, landscape science and geophysics with applications of remote sensing and field research integrated through mathematical modeling methods. To achieve the goal, the identification of natural and disturbed landscapes using remote sensing data, and key areas for detailed research will be selected. Geophysical and drilling works will be carried out within the sites to establish permafrost-hydrogeological conditions, monitoring stations will be equipped to determine hydrogeological, hydrometeorological and geocryological characteristics, including sampling for isotopic and hydrogeochemical studies. As the main key sites, it is proposed to use the area of ​​the Kolyma water-balance station and the site on Anmangynda aufeis, for which there are long-term observation series in the 20th century. Field data will become the basis for improving the mathematical model of runoff formation, considering the relationship between groundwater and river runoff in the conditions of permafrost. Mathematical modeling will make it possible to quantitatively analyze the water balance of rivers considering various factors and project water availability both for specific industrial facilities and for the region as a whole.

Долгосрочное прогнозирование стоковых характеристик методом математического моделирования гидрологических процессов

In recent decades, climatic anomalies have been recorded that give rise to long-term changes in the hydrometeorological regime and the system of interaction of the water mass with the underlying surface, in particular, on channel and floodplain sections of rivers that are the site of underwater crossings of main pipelines. Currently, these changes are not taken into account during the course of design & engineering, construction and operation of underwater crossings, although the period of safe operation of the pipeline depends on the conditions that the engineering structure is exposed to. In this article, the influence of long-term changes in the hydro-meteorological situation on the runoff characteristics of the river Ob located near the alignment of the underwater crossing of the Aleksandrovskoe – Anzhero-Sudzhensk main pipeline has been considered. It has been determined that the method developed by the Russian State Hydrometeorological University is optimal for runoff characteristics prediction. Using this mathematical model, changes in the hydrometeorological regime have been assessed in the river Ob – Aleksandrovskoe section, a violation of its stationarity in 1979–1980 was established. The main flow-forming factors – the amount of precipitation and the temperature regime – have been determined. Approbation of the runoff formation model showed that the maximum convergence of the predicted and actual values is observed when using predictions with an additional parameter. To predict the runoff characteristics for 2011–2040, climatic scenarios were used as initial data – representative concentration trajectories according to which the temperature and precipitation amount is expected to increase during the specified period of time. The results obtained indicate a tendency for an increase in water content and a redistribution of runoff vs. time, which, in turn, will catalyze the intensity of the processes of channel and floodplain deformation. It is concluded that it is necessary to consolidate the use of the prediction of runoff characteristics in regulatory documents in order to increase the efficiency of measures to ensure the safe operation of underwater crossings of trunk pipelines, as well as the accuracy of calculations in the design and construction of these facilities.

РЕГІОНАЛЬНА МЕТОДИКА ДЛЯ ВИЗНАЧЕННЯ МАКСИМАЛЬНОГО СТОКУ ВЕСНЯНОГО ВОДОПІЛЛЯ РІЧОК CУББАСЕЙНУ Р.ДЕСНА В УМОВАХ ЗМІН КЛІМАТУ

The results of development of the regional methodology for calculating the maximum water runoff of the rare probability of exceedance for the rivers of the sub-basin the Desna River under the conditions of modern climate change are presented. As basic for calculation authors used a modern modified version of the operator model of runoff formation developed at the Odessa State Environmental University to determine the characteristics of spring flood, which allows taking into account the influence of climate change on the calculated characteristics of the maximal runoff modules. The advantage of the proposed method is that it is based on the theory of channel isochrones, which allows describing the natural process of formation of runoff in the form of the operator “slope tide – channel runoff”. To substantiate the basic calculation parameters of the author’s methodology, was used the data of direct observations on the hydrological characteristics of the maximum waterrunoff of the spring flood (water discharges, depth of runoff and duration of the influx) and meteorological factors of its formation (maximum snow supply and precipitation during spring flood) for the period since its beginning to 2015, including. In the process of standardization of the main components of the proposed methodology, methods of statistical processing, spatial generalization, numerical problem solving and mathematical modeling were used. To account for possible climate change, the original author’s scientific and methodological approach is proposed, which is to determine “climate corrections” on the basis of modern baseline data – maximum of the water snow supply and precipitation during spring flood and runoff coefficients of the water, taking into account their dependence from long-term annual air temperatures that are projected according to the developed climate models and scenarios. The modified version of the operator model is proposed to be used as a regional calculation technique for determining maximum runoff modules of the rare probability of exceeding for ungauged rivers in the Desna sub-basin during the passage of the spring flood.

Application of the operator model of runoff formation to determine the average long-term values of maximum water discharge of spring flood in the Pivdenny Buh basin

In the context of Ukraine's integration into the European Union and implementation of the main provisions of Directive 2007/60/EC which implies assessment of potential hydrological risks, long-term factors of their formation, in particular the effects of climate change and the trend of river water regime changes should be taken into consideration. With this in mind, given the presence of both current long-term tendencies to reduction of runoff layers (volumes) and maximum discharge of water of spring flood across the Ukrainian rivers there is an important task to identify, using the modern initial data, both the average long-term values of these characteristics and different probability of their exceedance probability.
 For the first time, the authors of the study implemented an operator model of runoff formation to determine the average long-term values of maximum water discharge of spring flood in the basin of the Pivdenny Buh using meteorological characteristics (snowpack and precipitation) and runoff coefficients as basic parameters.
 The model was applied to determine the maximum runoff modules of spring floods for the rivers with a wide range of catchment areas affected by different physical and geographical conditions within the Pivdenny Buh Basin.
 Application of the operator model allowed the authors of the article to calculate and summarize all input parameters of the calculation model, including those obtained from observational data (snowpack, precipitation) and those that can't be measured by the hydrometeorological network (runoff coefficient, temporal irregularity coefficient and duration of surface inflow of snowmelt and rain water, transformational function of the flood waves layering under the influence of channel lag, coefficient of channel and floodplain regulation) for the rivers of the Pivdenny Buh Basin.
 The verifying calculation related to determination of the average long-term values of the maximum modules of spring flood runoff using the operator model showed satisfactory concordance with the initial data and this allowed recommending it for practical application for the rivers of the Pivdenny Buh Basin, including those that haven't been studied from the hydrological perspective.

The Impact of Climate Change on Surface, Subsurface, and Groundwater Flow: A Case Study of the Oka River (European Russia)

The article considers an approach to evaluating the change in surface, subsurface and groundwater flow on a large river catchment exemplified by the Oka River basin. The study is based on the synthesis of a physical-mathematical model of runoff formation and atmosphere–ocean general circulation models. The paper presents the results of calibration and verification of a hydrological model over a period of history, as well as the assessment of reproduction accuracy of meteorological and hydrological characteristics according to the data of global climate models and observation data. Based on an ensemble of atmosphere–ocean general circulation models, the changes in meteorological (air temperature, precipitation, air humidity deficit) and hydrological (surface runoff, soil moisture content, groundwater flow) characteristics by the middle and the end of the 21st century have been calculated, under the scenarios RCP 2.6 and RCP 6.0 with regard to the historical period.

Sensitivity Assessment of a Runoff Formation Model in the Mozhaisk Reservoir River Basin

The physically based model of river runoff formation with a daily resolution ECOMAG was adapted for the Mozhaisk Reservoir with an area of 1360 km2. A large series of numerical experiments were carried out in order to investigate the sensitivity of the model to the spatial resolution of land surface characteristics and the size of calculation cells. Digital elevation models (DEMs) of three different spatial resolutions (50, 100 m, and 2 km) were used along with model schematizations of the catchment area and river network with varying detail. In addition, the model sensitivity to sets of calibration parameters when modelling genetic runoff components was studied, as a part of the approaches to mitigating the problem of equifinality. The importance of incorporating additional hydrochemical information for a correct description of the spatial and temporal genetic structure of river runoff is shown.

Assessing the Sensitivity of a Model of Runoff Formation in the Ussuri River Basin

A physically based model of runoff formation with daily resolution has been developed for the upper part of the Ussuri basin with an area of 24400 km2 based on ECOMAG hydrological modeling platform. Two versions of the hydrological model have been studied: (1) a crude version with the spatial schematization of the drainage area and river network based on DEM 1 × 1 km with the use of soil and landscape maps at a scale of 1: 2500000 and (2) a detailed version with DEM 80 × 80 m and soil and landscape maps of the scale of 1: 100000. Each version of the model has been tested for two variants of meteorological inputs: (1) meteorological forcing data (temperature, air humidity, precipitation) at eight weather stations and (2) with the involvement of additional data on precipitation collected at 15 gages in the basin. The model has been calibrated and validated over a 34-year period (1979–2012) with the use of runoff data for the Ussuri R. and its tributaries. The results of numerical experiments for assessing the sensitivity of model hydrological response to the spatial resolution of land surface characteristics and the density of precipitation gaging stations are discussed.

Assessing Amur Water Regime Variations in the XXI Century with Two Methods Used to Specify Climate Projections in River Runoff Formation Model

A regional numerical physico-mathematical model of river runoff formation is used to study the possibility to assess long-term variations of water regime characteristics in the Amur R. in the XXI century. Two methods were used to specify climate projections as boundary conditions in the hydrological model: (1) based on the results of calculations with an ensemble of global climate models of CMI5 project, (2) based on data obtained by linear transformation of series of actual meteorological observations with the use of normal annual climate parameters calculated by climate models. The results of numerical experiments were used to analyze the sensitivity of the anomaly of Amur normal annual runoff to changes in the climate normals of air temperature and precipitation. The anomalies of normal annual runoff were shown to respond similarly (within the accuracy of sensitivity coefficient estimates) to changes in the appropriate climate normals, whatever the way of specifying climate projections.

Runoff Formation Model for the Amur River Basin

ECOMAG software complex was adapted to simulate river runoff in the Amur basin using data from global databases (relief, soils, landscapes). The results of model calibration and verification were used to give a statistical estimate of the efficiency of river runoff calculation over a long period based on standard data of meteorological and water management monitoring. The results of calculations using the developed runoff formation model were used in the space and time analysis of the formation conditions of 2013 flood in the Amur basin.

Assessing possible changes in Selenga R. water regime in the XXI century based on a runoff formation model

The runoff of the Selenga R., the largest tributary of Lake Baikal, in recent two decades corresponds to a low-water period. Such decrease can be due to the global climate processes, which have an effect on the amounts of precipitation onto and evaporation from Selenga drainage basin, which is located in arid climate zone. The adaptation of Ecomag software complex to simulating river runoff in the Selenga Basin based on global databases (relief, soils, vegetation, and weather information) is described. The model was calibrated and verified, and the statistical estimates of calculation efficiency were constructed. The obtained model of runoff formation in the Selenga Basin was used to assess the possible changes in the climate and water regime in the XXI century with the use of data of global climate models under different scenarios of greenhouse gas emissions. Throughout the XXI century, the Selenga R. runoff may decrease by 10–40%, depending on the forecasted climate conditions.