No abstract

The Sucevita catchment is affected by heavy rains, which produce annual floods with catastrophic effects. Among them, the material damages caused to the dwellings of Marginea village stand out. The present study examines the vulnerability of the population and buildings of a village situated in the eastern part of the Eastern Carpathians. By applying the multicriteria method, areas with high flood vulnerability were pointed out in the Sucevita catchment. Hydraulic modelling was carried out using the HEC-RAS software and revealed that 58 dwellings with high vulnerability will be affected in the case of a flood with an exceedance probability of 1% and 17 buildings in the case of a flood with an exceedance probability of 5%. By knowing the flood vulnerability zones, the appropriate measures can reduce the damages of a hydrological event. Moreover, the proper delimitation of the floodplain leads to adequate economic management and ensures the security of the population.

Changes in the climatic and hydrological variables in North-Eastern Romania indicate that the region has mostly a common evolution in terms of precipitation and hydrostatic level of groundwater. This can influence human communities in the region, given that sources of public water supply are predominantly from underground. In the analysed region with more than 8.000 sqm, 50% of the population lives in the rural area, where the main water supply source is provided by the underground water, mainly from individual wells with depths between 1 and 10 meters (only 10% from the rural population is connected to a centralized water supply system). That means the underground water resources are subject to overexploitation, especially given the prevailing economic activities associated with agriculture and construction involving high water consumption, predominantly from underground. Seasonal and annual data series of precipitation and hydrostatic level over a period of 31 years and collected in 36 hydrogeological stations (73 wells) and three weather stations have been used. The trends were detected by employing Mann-Kendall test and Sen's slope, and the correlation between the two variables was performed based on BravaisPearson correlation. The main results of the paper are: increasing trends are dominant both for annual and seasonal data sets of precipitation, but the great majority of the slopes detected are not statistically significant. In winter, precipitations have a decreasing trend and the slopes are statistically significant. In terms of hydrostatic level, most of the trends detected for nearsurface wells are decreasing, while in depth, increasing trends are dominant; the most important change was seen in the deep gap between 200 and 300 cm; correlation between precipitation and hydrostatic level is stronger and more frequent for summer (more than 86% of pairs were found statistically significant) and autumn (more than 80%), and is fable and less frequent for spring and winter due to trans-seasonal distribution of precipitation.

Concentration of time (Tc) is a frequently used parameter in the evaluation of the hydrological response of different sizes hydrographic basin in case of rainfall events. The present study is innovative, because it has created an index that identifies the small-sized hydrographic basins that are exposed to the risk of flooding. The Moldavian Plain is an area located in the northeast of Romania where the local population is frequently affected by floods and flash floods caused by heavy rainfall events. The main purpose of the current study is to identify the settlements located in the small-sized hydrographic basins, which are associated with low concentration times and powerful surface runoff. The empirical method was applied in order to calculate the Tc for rainfall water, for each drainage basin, for a time class less than 6 hr. Calculations of the runoff water were also done for a theoretical extreme precipitation event, corresponding to the 1% occurrence probability. A total number of 312 basins were identified that are smaller than 30 km 2 , out of which 112 have Tc of less than 6 hr. These basins, in particular, pose flood risk for 12.4% of the villages and towns in the study area.

During the last 30 years, the Romanian economy has faced different challenges due to structural readjustments, overcoming crisis and globalization. The share of primary and secondary sectors in the gross domestic product have strongly decreased, while the services have taken off. The main objective for this study is to observe how these economic readjustments can be assessed and measured using the Corine Land Cover datasets from 1990, 2000, 2006, 2012 and 2018 (with special observation on the range 2006 and 2018, after Romania was included in European Union). Despite some of the methodological limitations (like the minimum surface change), the Corine Land Cover turned out to be a powerful tool and it allowed us to detect an intense correlation between the socioeconomic and the structural trends in land use, in specific spatial contexts. The artificial surfaces are constantly increasing and this trend is rather visible as a distance function to the major Romanian cities. The most interesting changes occurred in the case of the agricultural polygons. The main trend emphasized by our analysis regards the redeployment of large farms in areas of agronomic and environmental territorial optimum. Such is the case for vineyards (after a decline during 2000–2006) and for annual cultures. All these changes in land-use patterns are too complex to be encompassed by a single methodology, which is why we used different tools, ranging from spatial analysis to geo-economic modeling, in order to detect how the Corine Land Cover datasets might be used for a better understanding of the Romanian economic readjustments.