METHOD TO ASSESS THE EXTREME HYDROLOGICAL EVENTS IN DANUBE FLUVIAL DELTA

Method to assess the extreme hydrological events in Danube fluvial Delta. In this paper the subject is about of testing a method for Romania to assess the extreme hydrological events. In this paper through hydrological extreme events it should be understood as the extreme droughts and the extreme flooding. The place to be tested this method for Romania is the Danube Delta, fluvial delta to be more precisely. The importance of the area consists in the fact that is the third Delta of the Europe (after the Volga’s and Kuban’s). The method that is supposed to be tested on a specific part of the delta is aiming to rise the knowledge about the extreme hydrological events (drought and flooding) and to be able to respond in an appropriate way to these. For this paper it will be taken into account the hydrological events occurred in 2003 (the exceptional drought) and in 2006 (the exceptional flood). To do the analysis there were used satellite images (LANDSAT) from the period that was taken into account and additional there were used the hypsometrical model of the Danube Delta for the specific area. The first two datasets (2003 and 2006 satellite images) give information about were the border of the water (in drought period and respective in flooding one) reached. The second dataset (the delta’s hypsometry) give information about the altitude of the terrain in order to establish which areas, at a certain water level, are flooded. The result of these datasets combination is the calibration of the hypsometrical model of the Danube Delta, in that region, regarding the hydrological events in the sense of building-up the hydrograds as isolines. The new approach of this matter can be more concrete and makes easier to see on the cartographic support the hydrologic events. The information obtained from these datasets makes the awareness regarding the extreme hydrological events to be higher and respective the measures taken to mitigate these will be more efficient

MORPHO-BATHYMETRIC PARAMETERS OF RECESS CRUCII LAKE (STÂNIŞOAREI MOUNTAINS)

Morpho-bathymetric parameters of recess Crucii Lake (Stânişoarei Mountains). Crucii Lake from Stânişoarei Mountains was formed in 1978 as a result of riverbed dam Cuejdel after a landslide triggered on the western slope of Muncelul Peak. The event led initially to a small accumulation of 250-300 acvatoriu m, 25-30 m wide and 4-5 m maximum depth. In the summer of 1991 following the construction of a forest road in the flysch, and amid a high humid conditions, the slide was reactivated, leading to the formation of the largest natural dam lake in Romania. It has a length of 1 km, area of 12.2 ha, maximum depth of 16 m and a water volume of ca. 907.000 m3. Morphometric and morpho-bathymetric measurements performed in the summer of 2011, with the help of the integrated 1.200 GPS of Station Leica System 1.200 surveying measurements and bathymetric measurements Valeyport Ecosounder Midas showed new values for the morpho-bathymetric parameters. Among them stands out: 13,95 ha area, perimeter 2801,1 m, maximum length of 1004,82 m, 282,6 m maximum width, maximum depth 16,45 m. To achieve the numerical model of the lake basin were more than 45.000 points bali reading, with equidistance of 0,25 m. The scale of detail work aimed to draw up a proper database to eliminate suspicions about the old analytical methods inaccuracies. At the same time was studied the evolution of the lake’s basin in the context of relatively recent geomorphological changes

The inventory and typology of the wetlands and deep waters from the Moldavian Plateau (Romania)

The Moldavian Plateau is positioned in the east of Romania, between the Eastern Carpathians in west, the Romanian Plain to the south, the Ukrainian border to the north and Prut Valley (border with the Republic of Moldavia) in east. Although the Moldavian Plateau is situated in the driest region of Romania (mean annual rainfall of 500-700 mm and average temperatures of 8-100C), the majority of the wetlands and of the low discharge rivers is found here. The existence of numerous wetlands, respectively small ponds, is due to the human activity and the lack of water resources. The impermeable clayey substratum favored the occurrence and survival of a large number of wetlands. Most of them are found in the Moldavian Plain (north), and the fewest to the south, in the Covurlui Plateau. The disappearance of wetlands from the region’s south was caused by the accelerated erosion (determined by the human activity, through deforestations and inadequate tillage), that induced an intense sediment transportation, with effects on the valley floor aggrading phenomena. The most important wetlands are those developed along the two main rivers – Prut and Siret. Unfortunately, Siret’s floodplain has been in most of its part dammed, and the wetlands entered the agricultural use. The map with the repartition of the wetlands is a product obtained through field investigations, through the consultation of the 1:50000 topographic maps, of aerial photos and satellite images’ interpretation (LANDSAT TM7) from the years 2000-2005. For the interpretation of the satellite images we appealed to the Corine Land Cover 2000 methodology