Search Results

You are looking at 1 - 6 of 6 items for

  • Author: Ivan Kirvel x
Clear All Modify Search
Open access

Ivan Kirvel, Mikhail Kukshinov, Alexander Volchek and Pavel Kirvel

Abstract

The article concerns the study of the influence of river reservoirs of Belarus on the evolution of river channels in their downstream pools. On the basis of observational data from the Republican Hydrometeorological Center of the Republic of Belarus (RHMC), as well as own field observations a quantitative evaluation of the change of the main channel formation factors, the direction, horizontal and vertical parameters of deformation of the riverbeds below dams has been performed. Changes in the type of channel processes for the regulated parts of rivers have also been assessed. It has been found that the investigated reservoirs accumulate up to 65% of the sediment transported by the river in a suspended state. Restoration of the water turbidity to values close to the natural regime occurs at a distance of 20 km downstream from a dam of small reservoirs, and up to 50 km downstream from a dam in the case of medium-sized reservoirs. The degree of the riverbed deformations downstream from a reservoir is defined by the geological and lithologic structure of the channel bottom deposits. If there are easily washed sand deposits at the bottom, then the dominant process is deep erosion. If sediments are more heterogenic with increased admixture of gravel-pebble material the development of directed deep erosion is reduced. The change of the existing type of channel processes of regulated rivers is due to the imbalance between the main factors of channel formation in the initial period of the operation of new water-engineering systems (5-7 years). The observed changes are typical of rivers with sandy riverbed.

Open access

Ivan Kirvel, Mikhail Kukshinov and Pavel Kirvel

Abstract

The article is dedicated to the problem of the transformation of rivers’ temperature conditions influenced by artificial reservoirs. A quantitative estimation of average water temperatures over ten days, and maximum and average annual water temperatures of regulated rivers downstream of reservoirs was made on the basis of the data analysis of a complete period of instrumental observations of the Republican Hydrometeorological Centre of the Republic of Belarus. It is established that the character and the parameters of the transformation of temperature conditions of the regulated rivers along with morphometric features of the reservoirs are determined by the meteorological conditions of the year and the operating conditions of the water-engineering system. The length of the cooling period effect varies from 20 days downstream of small reservoirs to 50-70 days downstream of small and average size reservoirs. The warming effect is less significant by temperature, but lasts longer and is appreciable around 200-240 days in a year. An increase in the average annual water temperature up to 0.5°C and a decrease in maximum temperature down to 1.1°C are observed in the tail-water of average size storage pools. Small size storage pools demonstrate an annual increase in annual water temperature up to 0.3°C and a decrease in maximum temperature down to 0.3°C. Small size water pools show an increase both in annual water temperature up to 0.5°C and maximum water temperature up to 0.3°C. Typical changes in temperature conditions of rivers are observed for a distance of 130 kilometres below the dam of average size water pools, along 70 kilometres in small water pools and along 30 kilometres in tiny ones.

Open access

Ivan Kirvel, Alexander Volchak and Sergey Parfomuk

Abstract

As a result of the conducted investigations of the level fluctuations in lake naroch the initial data are divided into 3 components: a polynomial regression that makes it possible to find out an independent on time law of trajectory, a periodic component of sinusoidal type and a residual sequence of independent random quantities. Modeling of the trajectory fluctuations is based on the deterministic part, consisting of the regression of the 8th order and periodic component, and also the random part, consisting of independent equally distributed quantities. Using this model it can be modeled the trajectory of the level fluctuations in lake naroch. The modeled trajectory by 200 years long demonstrated the probability of exceeding of maximum annual level, equal 1 per cent.

Open access

Aleksandr A. Volchak and Ivan Kirvel

Abstract

One of the soil fertility parameters is water content in the root zone; therefore the estimation of the transformation of water resources in mineral soils of Belarus is rather relevant. The analysis of plant available moisture content (PAMC) was conducted for the topsoil layer of 50 cm thickness for the period of monitoring from 1960 until 2001. Results were submitted as maps on the basis of which the spatial and time variability of the PAMC was estimated. The quantitative estimation of changes in the plant available moisture content was carried out with the help of gradients of linear trends

Open access

Aleksandr A. Volchak and Ivan Kirvel

Abstract

Lake level is one of the most important lake characteristics which allows the results of different effects to be identified and detected. In this work time series of the water levels of Belorussian lakes were analysed in order to detect pattern variations, to evaluate quantitatively the transformation of the hydrological regime of lake ecosystems and to develop prediction models. The possibility of plotting predicting models of lake water levels one year in advance was shown. The complication in plotting predicting models is in its individuality, the huge volume of initial data and the impossibility of immediate assessment of the results. Additional complications are caused by the inhomogeneity of time series of water levels in lakes.

Open access

Alexander A. Volchek, Ivan Kirvel, Sergey Parfomuk and Roza Makhambetova

Abstract

The optimal number of hydrological monitoring stations for the annual values, the maximum spring, the minimum summerautumn and the minimum winter river runoff in Belarus is determined. The research on optimization of the hydrological network of Belarus led to a conclusion about the optimum number of hydrological stations in the country, but in the case of observing the values of the annual runoff, the number of the existing plants is the minimum necessary, and reducing their number is inadmissible. On the basis of trends in air temperature changes, precipitation and humidity deficits from 1985 to 2009, the forecasts of these parameters are prepared until 2020. Taking into account the models of climatic parameter change, a possible change in the water regime of the rivers in the future is investigated.