Analysis of water surface area dynamics of the Teniz-Korgalzhin lake system by remote sensing methods

Abstract

Teniz-Korgalzhyn lakes are included in the list of Ramsar sites of international importance and are a place of concentration of a huge number of waterfowl and near-water birds. These are more than 60 fresh and salt lakes with a depth of 1-4 m. Changing the area of the water surface of lakes leads to a change in habitat conditions, species composition and number of birds. The article shows that the changes are associated with both natural and anthropogenic factors. The possibility of studying the dynamics of the area of lakes based on the methods of geoinformation analysis and remote sensing is considered. Several methods have been tested for calculating the area of the water surface of lakes using multizonal space images using specialized spectral indices. On the example of 18 lakes for each method, the mean square error of the accuracy of the results obtained was calculated. It is shown that for the study area the most reliable result is given by the modified normalized water index MNDWI. On its basis, the interannual dynamics of the area of the water surface of the Teniz-Korgalzhyn lakes for the period from 2006 to 2019 was analyzed. It is shown that the fluctuation of the total area of the water surface of the largest lakes during this period reached 2.5 times. At the same time, the trend towards a gradual increase in the area of freshwater lakes since 2013 is primarily due to the action of natural and climatic factors. A much more significant increase in the area of the salt lakes Big and Small Teniz is due to the additional inflow of water due to the breakthrough of the Tabiyak dam in 2015.