Methodology for surface water flood modelling based on analysis of digital elevation model and hydrological data

A methodology for surface water flood modelling is proposed, based on the use of small-scale mapping tools together with hydrological observation data. To reproduce the flooding surface during extreme floods, information on historical maximum water levels was selected, and a digital elevation model (DEM) was used as the cartographic basis. The proposed methodology is universal and provides possibility to determine the boundaries of the potential flooding area in river sections during extreme water levels, to identify objects in the potential flooding area, as well as to make operational decisions to prevent disastrous situations arising from floods and minimize adverse consequences. The results of application of the proposed method for certain river sections of the North Caucasus, a region characterized by a high degree of flood hazard, are presented

Два подхода к расчёту расчленения гидрографа стока реки с ледниковым питанием с помощью изотопных методов

Application of the stable isotope method in the balance equations used to calculate separation of the runoff hydrograph from the Djankuat Glacier basin is demonstrated. Simultaneous solution of equations of water, isotope and ion balances is applied to estimate contributions of different components and processes to formation of the Djankuat River runoff regime. For June 2014, we made calculations for the purpose to separate contributions of the spring (isotopically weighted) snow and winter (isotopically depleted) snow. Field works in the glacial basin Djankuat were performed during two ablation seasons, i.e. from June to September of 2013 and 2014. Two approaches were used when calculating separation of the runoff hydrograph by means of solution of systems of equations for isotopic and ion balances: 1) taking account of the isotope fractionation during snow melting, and 2) with no account for the fractionation. Separation of the hydrograph for June 2014 have shown that about 15–20% of the Djankuat River runoff is formed by spring snow melting, sometimes increasing up to 36%. Contribution of spring meltwater to the total runoff increases when the isotope fractionation during the snow melting is taken into account for the calculations. In this case, the contribution of spring snow changes from 30 to 50%.Рассмотрено применение метода стабильных изотопов в балансовых расчётах расчленения гидрографа стока с ледника Джанкуат. Изученные изотопные вариации стока на замыкающем створе р. Джанкуат для двух сезонов абляции 2013 и 2014 г. совместно с измерениями δ18О и минерализации различных источников питания р. Джанкуат (атмосферные осадки, снег разных сезонов, фирн, лёд и грунтовые воды) позволили расчленить гидрограф стока 2014 г. Применялись два методических подхода к расчётам: разделение гидрографа стока решением систем уравнений ионного и изотопного баланса с учётом изотопного фракционирования при таянии снега и без учёта фракционирования. Установлена величина погрешности расчётов с использованием значений δ18О и абсолютных концентраций 18О

GO-GN conceptual frameworks guide

This collaboratively written book brings together insights from a range of researchers into their use of conceptual frameworks in studying open education. Also included is an overview of different approaches to understanding the role(s) of theories and conceptual frameworks in doctoral research. In addition to discussing the different ways that conceptual frameworks are used we provide a (selective) overview of a range of conceptual frameworks and examples of their use. The GO-GN Conceptual Frameworks Guide is intended for those working in doctoral research but accessible enough to be used by anyone interested in carrying out a research project.Librar

Interrelation Between Glacier Summer Mass Balance And Runoff In Mountain River Basins

Measurements of summer mass balance Bs, made over the period 1946-2016, on 56 continental glaciers, located in the basins of mountain rivers in 14 countries, were analysed for the purpose of resolving several tasks: (a) constructing physically based interrelations between river flow Wbas and Bs; (b) estimating the representativeness of local measurement of Bs for enhancement of hydrological computations and for control of modelled values Wbas; and (c) use of time series of Bs for the evaluation of norms and extrema of Wbas. Results of the study of the outlined problem serve as the basis for making the transition of local glaciological characteristics to the basin-wide level by using the relationship between runoff and summer balance of glaciers. It includes also analysis and conclusions on the spatial and temporal homogeneity of averaging glaciological mass balance data by the sampling method

Methodology for surface water flood modelling based on analysis of digital elevation model and hydrological data

A methodology for surface water flood modelling is proposed, based on the use of small-scale mapping tools together with hydrological observation data. To reproduce the flooding surface during extreme floods, information on historical maximum water levels was selected, and a digital elevation model (DEM) was used as the cartographic basis. The proposed methodology is universal and provides possibility to determine the boundaries of the potential flooding area in river sections during extreme water levels, to identify objects in the potential flooding area, as well as to make operational decisions to prevent disastrous situations arising from floods and minimize adverse consequences. The results of application of the proposed method for certain river sections of the North Caucasus, a region characterized by a high degree of flood hazard, are presented

The role of seasonal and occasional floods in the origin of extreme hydrological events

Extreme hydrological events on the rivers of European part of Russia are closely related to the hydrological regime transformation answering recent climate changes. Rivers in this region used to be traditionally attributed to the Eastern-European type with well-pronounced seasonal flood wave and quite low flow period during summer and winter. During the last twenty years the role of the occasional floods became more and more important. Number of winter floods, connected with thaws rose dramatically, in the same manner as summer flash floods. In this study, the frequency and duration of extreme low flow and high flow events is analyzed. The deficits during hydrological year were calculated. Due to results increase in natural runoff regulation, does not reduce frequency of extreme events, in some regions it raises

EVALUATION OF GLACIER MELT CONTRIBUTION TO RUNOFF IN THE NORTH CAUCASUS ALPINE CATCHMENTS USING ISOTOPIC METHODS AND ENERGY BALANCE MODELING

Frequency and intensity of river floods rise observed in the North Caucasus during last decades is considered to be driven by recent climate change. In order to predict possible future trends in extreme hydrological events in the context of climate change, it is essential to estimate the contribution of different feed sources in complicated flow-forming processes in the alpine part of the North Caucasus. A study was carried out for the Djankuat River basin, the representative for the North Caucasus system. Simultaneous measurements of electrical conductivity, isotopic and ion balance equations, and energy balance modeling of ice and snow melt were used to evaluate the contribution of different sources and processes in the Djankuat River runoff regime formation. A forecast of possible future changes in the Djankuat glacier melting regime according to the predicted climate changes was done

Two approaches to hydrograph separation of the glacial river runoff using isotopic methods

Application of the stable isotope method in the balance equations used to calculate separation of the runoff hydrograph from the Djankuat Glacier basin is demonstrated. Simultaneous solution of equations of water, isotope and ion balances is applied to estimate contributions of different components and processes to formation of the Djankuat River runoff regime. For June 2014, we made calculations for the purpose to separate contributions of the spring (isotopically weighted) snow and winter (isotopically depleted) snow. Field works in the glacial basin Djankuat were performed during two ablation seasons, i.e. from June to September of 2013 and 2014. Two approaches were used when calculating separation of the runoff hydrograph by means of solution of systems of equations for isotopic and ion balances: 1) taking account of the isotope fractionation during snow melting, and 2) with no account for the fractionation. Separation of the hydrograph for June 2014 have shown that about 15–20% of the Djankuat River runoff is formed by spring snow melting, sometimes increasing up to 36%. Contribution of spring meltwater to the total runoff increases when the isotope fractionation during the snow melting is taken into account for the calculations. In this case, the contribution of spring snow changes from 30 to 50%

RECENT TRENDS Of RIVER RUNOff IN THE NORTH CAUCASUS

Based on observational data from 70 hydrological stations in the North Caucasus an evaluation of present values of mean annual runoff, minimum monthly winter and summer runoff was carried out. Series of maps was drawn. Significant changes in mean annual. minimum monthly and maximum runoff during last decades have been revealed in the North Caucasus. A rise in both amount of water availability and potential natural hazard is characteristic of the most of the North Caucasus that is considered to be caused by recent climate change. Mean annual runoff during 1978-2010 increased compared to 1945-1977 by 5-30 % in the foothills and by 30-70% in the plain area. An increase in winter minimum monthly runoff is as well most intensive in the plain part of study area (>100%). Within the foothills it amounts to 50-100%. In mountainous area long-term oscillation of winter minimum monthly discharge strongly depends on local factors, such as geological structure. The rate of the increase in summer minimum monthly discharge regularly grows from central foothill part of Northern Caucasus (30-50%) to the Western plain territory (70-100%). In Kuban river basin 30% of analyzed gauging stations show positive trend in maximum instantaneous discharge, while 9% negative. On the contrary, in the Eastern part – Terek river basin – negative trend in maximum instantaneous discharge is prevalent: 38% of gauging stations. Positive trend in Terek river basin is characteristic of 9.5% of analyzed gauging stations

Transitional accommodation for refugees

International audienceIt is generally accepted that drought is one of the most costly weather-related natural hazards. In 2015, a long-lasting drought hit Europe, particularly affecting central and eastern Europe. In some regions it was the driest (North Slovakia) and in others (Czech Republic and Poland) it was the second driest summer of the last 50 years (following 2003). Key questions are: (i) how extreme are these events, not only in terms of hydro-meteorological characteristics but also impacts? and (ii) how are these impacts managed