Evolution of Danubian islets from Balta Ialomitei hydrographic system (Km 345-241) between 1908-2016

• Main Authors: IORDACHE Gabriel, BONDAR Constantin, ANGHEL Sorin, MALAGEANU Marian
• Format: Article
• Language: English
• Published: CITDD Publishing House 2018-05-01
• Series: Scientific Annals of the Danube Delta Institute
• Subjects: islet; Danube branch; critical points; hydrographic changes
• Online Access: http://www.ddniscientificannals.ro/scientific-annals/24-volume-23/149-vol21_art03-25
• ISSN: 1842-614X; 2247-9902

The studied area is part of the Balta Ialomiţei hydrographical system and belongs to the lower sector of the Danube, being characterized by the many branches, secondary branches with islets between them, indicating a state of hydro morphological instability of the riverbed. The sector analyzed in this paper is between the bifurcations with the Bala branch (Turcescu Islet) from km 345 and up to Vadu Oii, at the bifurcation with Borcea branch, at km 241.The hydrographic changes that occurred over time in the hydrographic nodes Danube-Bala and Danube Borcea branch, have significantly affected the morph hydrography of the secondary branches. Thus, in the Bala-Danube bifurcation area, the consequences of riverbed changes were reverberated by increasing the takeover capacity of water by Bala branch to the detriment of Danube branch. This leads to a decrease in depths on the Danube branch at low waters, endangering the optimal depths for navigation, the occurrence of critical points for navigation downstream, changes of islets and the main elements of riverbed. Thus, along the analyzed range, the number of islets present in the riverbed of the Danube decreased between 1908 and 1960, remaining constant and with minor changes until 1990, after which there was a consistent increase of the number of islets until the end of the study period in 2016.Also, it find an increase in the total length of the islets and also changes in their geometry and position, especially at the smallest of them.