Bâsca


The Bâsca, also called Bâsca Mare in its upper course, and Bâsca Roziliei in its lower course, is a left tributary of the river Buzău, in Romania. It discharges into the Buzău near Nehoiu.

Geographic position

Positioned in the external region of the curvature of Carpathians, the Bâsca drainage basin has an area of. Its length is. It lies at an average altitude of 1,081 m between the Lăcăuți Peak and the confluence with the Buzău River.

Geology

From the geological point of view, the Bâsca River Catchment overlaps the orogenic unit of the Eastern Carpathians, where the external Paleogene flysch is predominant, including: sandstones, marl, conglomerates.
This area is characterised by tectonic uplift and by severe seismicity related to the Vrancea Epicentral Area, being affected by deep-seated landslides. Lithology is dominated by the presence of the hardest and hard rocks, covering 96.7% of the catchment surface.

Climate

The climate of the Bâsca Catchment is temperate-continental. Föhn phenomena moderate the characteristics parameters of climatic elements, e.g. average multiannual atmospheric temperature between 1.2 °C at the Lăcăuți meteorological station between 1961 and 2000, see Table, and 2.4 °C at the Penteleu station, combined with precipitations of 664.3 mm at Penteleu and 830.1 mm at Lăcăuți.

Hydrography

Major river tributaries

The following rivers are tributaries to the river Bâsca :
RiverCatchment area River length
Bâsca Mică23846.5
Bâsculița4011.5
Poplița34.2 9.3
Cireș32.4 11.1
Păltiniș25.19.7
Ghiurca Mare23.39.6
Dârnăul Mare21.510.6
Delușor20.96.9
Pătac18.510
Giurgiu16.26.5
Șapte Izvoare15.66.6
Milei15.86.4
Saroș14.97.8
Corongoș12.85.3
Brebu11.16.6
Ruginosul11.85.1
Cernat11.16.7
Slobod9.26.2

Reservoirs

On the Bâsca River the project "Hydropower Siriu – Surduc Development”, has been developed. This project includes a permanent water reservoir "Cireșu" on the upper part of the Bâsca River and an underground derivation "Surduc – Nehoiașu", from Cireșu Accumulation and Bâsca River towards the "CHE Nehoiașu II” hydroelectric power station.

Hydrology

The most common risk hydric phenomena affecting the catchment area are floods and flooding. Associated to these are processes of river channel dynamics, landslides and falls. The frequency analysis of the maximum monthly discharge indicates that the month with the highest flood potential is July, followed by June. In July were recorded the highest floods. Among them, remarkable for their socio-economic consequences where those from 1969, 1975, 2002. The annual maximum flow of the Bâsca River varied between 39.4 m³/s and 960 m³/s. Exceptionally floods were recorded in the years: 1975, 1969, 1991 and 1985. Multiannual average flow at this station is about 12 m³/s. Damaging effects caused by floods and flooding have determined property damage, such as flooded homes, landslides and slope destabilization of versants; destruction of undermining and hydrotechnical works, affecting sections of the roads and humans casualties.

Demographic and socio-economic features