Romania Hydrography

By | December 23, 2021

Thanks to the extension of the mountains, Romania, despite its steppe-like climate, has a well-organized hydrographic network, except in a part of the Carpathian foreland plains (southern Oltenia, south-eastern Muntenia and Bessarabia) and in Dobruja, in which the water draining on the surface does not represent more than a quarter of the precipitations and where these do not always balance evaporation. These plains do not give rise to any autonomous watercourse and are crossed only by some river descending from the mountains or from the high hills; a Carpathian river, such as the Ialomiţa, is also reduced to a ribbon of pools at the end of the summer. There are, however, some underground aquifers, which can be reached;

The infiltration of water into Quaternary pebbles or Neogenic sands at the foot of the mountains gives rise to deeper aquifers of an artesian character, used with drilling in the surroundings of Ploesti, Bucharest and Craiova. Similar conditions occur, on a smaller scale, in some plains of eastern Transylvania and in the foothills of the Hungarian plain, where Romania has a series of cities such as Timişoara and Arad. For Romania 2017, please check mathgeneral.com.

With the exception of northern Dobruja and Bessarabia (drained almost entirely by the Dniester) all of Romania belongs to the Danube Basin. The Transylvanian rivers, with the exception of the Olt and the Jiu, all reach the Danube by means of the Tisza: the Someş to the north and the Mures to the south divide the river basins.

Someş is made up of two roughly equal branches. The eastern one collects the waters of the western slope of the Bucovina massif, a well-watered and very high region; the western one comes from the very snowy plateaus of Bihor. Therefore the river that flows northwards, to leave Romania at Satu-Mare, is well fed, with strong spring floods. The Mureş receives from the Bihor only torrential tributaries such as the Arieş; almost all of its waters descend from the volcanic chain of the Hargitta or from the Transylvanian-Banatic Massif. It is, between Deva and Arad, a mighty watercourse, with spring growths, subject to strong floods even after summer storms, and whose average flow corresponds to a water section of 30 cm.

Three torrentizî watercourses descend from the western slope of Bihor, the Criş Repede, the Criş Alb and the Criş Negru. Finally, the Timis and its tributary the Bârsava, coming from the Banat mountains, flow with a steep slope into the Timişoara plain, where their waters frequently flood vast areas and form a water table close to the surface and therefore dry in summer.

The Danube forms the Romanian border from Baziaş onwards. In Moldova it begins to sink into the mountains up to the narrow called Iron Gate (Porţile de Fier) near Turnu-Severin (60 km.). The tapering of the bed (reduced several times to less than 200 m.) And the irregularity of the slope, which give rise to rapids where the water boils over rocky banks, do not significantly modify the regime of the great river which it established in the Hungarian plain, under the combined influence of Carpathian tributaries such as the Tisza, and evaporative losses in the slow and winding course downstream from Budapest. The alpine growths, with their maximum in July, still maintain a high flow rate in the middle of summer while the Tisza brings a contribution determined by the rains and the melting of the Carpathian snows in spring; evaporation significantly reduces the flow rate in autumn (minimum in October).

In Orşova (see danube, XII, p. 357) the average flow rate is 4200 cubic meters. Despite the decrease in slope that occurs after the outlet into the plain and the influence of the steppe climate, it still increases up to the delta.

The Romanian tributaries undoubtedly affect this increase more than the Bulgarian ones, and could affect even more without the losses that affect all these rivers in their lower reaches across the lowlands of löss. All emerge from the Carpazî with very steep slopes (5 ‰ for the Jiu), and branch out in thin threads on large pebble beds, completely filled only for a few days during the spring floods or for a few hours after the summer showers.

Only the Olt and Siret have a slightly less irregular regime. The first comes from Transylvania, where it is copiously fed by runoff on the Hargitta volcanic range, on the west side of the Moldovan flysch ranges and the north side of the Făgăraş. After carving the mountain in the Torre Rossa gorge (Turnu Roqu), it can almost be compared to Someq. However, its flow rate in autumn and winter is very low compared to the abundant spring and early summer waters (maximum in May and July). The Siret has a less steep slope (0.7 ‰ instead of 2) and a more constant flow up to the Galaţi plain, where its tributaries Putna, Râmnic and Buzău converge, in a very low slope sinking region, exposed to vast floods.

The Danube is completely Romanian downstream from Turtucaia. The altitude being only 15 m. at 300 km. from the sea, the width of the flood plain (Balta) which widens more and more up to the delta (25 km. towards Brăila). The average regime has changed only in the sense of a relatively more accentuated water poverty in autumn (minimum in October) and a delay in high waters, the maximum of which is in May-June in Brăila. The floods are always in spring and come in successive waves originating mostly in the upper and middle course. The overflows inundate the whole Balta, transforming it into a real lake, from which the tops of the willows emerge. Winter, a season of shallow waters, is also that of frost, which lasts between 12 and 96 days in Brăila for the main course. The thaw prolongs the period in which navigation is suspended.

To complete this description of the great river, it is necessary to note the abundance of turbid, which at high waters reach 2 gr. per liter and explain the rapid advance of the delta.

Romania Hydrography