Peatlands are recognized as important landscape elements and their disturbance, followed by the loss of their ecohydrological functions, leads to falling water tables and degradation. Sometimes, the shortage of hydrological monitoring data impedes the detection of degrading peatland areas. The application of cost-effective remote sensing methods for assessment of humidity conditions permits monitoring of a large area and longer periods of time. Therefore, in this study, we assessed the links between hydrological parameters and the normalized difference vegetation index (NDVI) as well as identifying spatio-temporal patterns in the condition of raised bog vegetation, according to NDVI, in the Čepkeliai raised bog, a semipristine peatland in south-eastern Lithuania. Time series of NDVI (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017)(2018) were obtained from the moderate resolution imaging spectroradiometer and compared with field measurements. A strong positive correlation between NDVI and water table depth was found. Moderate (for the whole raised bog) and strong (for control subbasin) positive correlations between NDVI avg and annual minimum flow over 30 and 7 days were found. This confirms that NDVI could be treated as an appropriate indicator, showing the degradation processes of the raised bog ecosystem and could be applied in its management. Analysis of the interannual NDVI avg variation confirmed the prevalence of stable favourable conditions during the growing season with a slight decrease in NDVI max over last 4 years. Meanwhile, analysis of spatial NDVI variation revealed obvious spatial patterns where possible degradation processes tend to appear. KEYWORDSNDVI, peatland degradation, peatland water resources, raised bog, water table depth

The study based on the thermodynamic computer programme PHREEQC presents changes in migration forms of heavy metals in groundwater calculated based on the changing pollution of groundwater under the hydrogeological conditions of a landfill (sandy aquifer). Under neutral medium conditions, as the pollution of shallow groundwater and the content of organic matter decrease, the amounts of heavy metals in ionic form is found to increase considerably. The intensive pollution zone shows the highest percentage of migration forms of carbonates. Furthermore, the formation of organochlorines causes the formation of migration forms of cadmium chloride in the intensive pollution zone. The calculated saturation index values show that crystallization plays the main role in heavy metal attenuation in glaciofluvial alluvial aquifers.

The work analyzes data of environmental geological mapping, groundwater monitoring of the region municipal waste landfill. This study examines the effectiveness of a modern landfill liner system in minimizing migration of pollutants in the groundwater of an open hydrogeological system. The results showed that dissolution of carbonates and dilution were the major processes controlling groundwater quality. In the landfill’s direct impact zone, groundwater was only weakly polluted with biogenic components. Increase in concentrations of these chemical components in this zone was related with the groundwater and surface runoff water flowing from adjacent areas. We can state that the modern landfill liner system we analysed is efficient and has no adverse effects on groundwater quality under hydrogeological conditions favourable for the spread of pollutants. However, in case of an accident, pollutants might pose a great threat on the safety of groundwater. Therefore, even modern landfill liner systems are not recommended to be constructed in open hydrogeological systems.

Coastal dunes are recognized as one of the most threatened ecosystems, the formation of which mainly depends on two opposite processes—sand dunes overgrowth and formation of open dunes. The application of cost-effective remote sensing methods permits monitoring the interaction of these two processes over a large area and long periods of time. Therefore in this study we assessed the links between hydro-meteorological parameters and the normalized difference vegetation index (NDVI) in Curonian spit coastal dunes landscape-a creation of human and nature integrity situated in the South eastern part of the Baltic Sea. Time series of NDVI (2000–2019) were obtained from the moderate resolution imaging spectro-radiometer and compared with hydro-meteorological parameters in three different ecosystems—forest, herbaceous and open sands. Moderate and strong positive correlation between NDVI and average wind speed was detected in non-forested ecosystems. Moderate positive correlation was detected between NDVI and the Baltic sea water level in all three analyzed ecosystems. Moderate positive correlation between NDVI and air temperature was found in forest ecosystem. This confirms that NDVI could be treated as an appropriate indicator, showing the interaction of coastal dunes overgrowth and formation of open dunes, and could be applied in its management that should be reconsidered under nowadays climate change.

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