Research of Data Sequences of Groundwater Levels with Gaps

Investigating the regime of groundwater levels is one of the main stages of hydrogeological research, which allows quantitative characterization of the process of formation and change of hydrogeological conditions in time. To date, there has been a problem in filling the series of groundwater levels (GWLs) that have gaps. During the formation of time series of data, there are usually gaps in connection with the change in the technique of observing the GWL, the untimely filling of data rows, the lack of the ability to conduct such observations, and others like that. However, it is not possible to completely exclude rows with spaces, as this may lead to inaccurate data while developing forecast and constructing predictive maps of groundwater levels. Therefore, the task is to compare the existing methods of filling the data series with spaces in order to choose the optimum for further work, with their practical verification.