The Morphological Impact of the Colibița Hydrotehnical System on the Bistrita Ardeleana Riverbed

Abstract

Large dams, as well as conventional hydrotechnical constructions with the role of breaking the drainage slope (waterfalls or bottom sills), flood mitigation or with the role of protection against floods (shore defences) have a profound impact on the environment. Due to these constructions, the ecosystems on the Bistrița Ardeleană river have undergone changes or even established new ones. This paper wants to highlight the morphological changes of the Bistriţa riverbed by analysing the transversal profiles made between 1972 and 2015. The profiles were made in the flow measurement section at two hydrometric stations, one being located in the upstream part of the river basin and the other before the Bistrița river flows into the Șieu river. By comparing the results obtained from the profiles made before the Colibița hydrotechnical system was started or completed with the data obtained from the profiles after the commissioning of the Colibița hydropower plant, we managed to highlight that the Bistrița Ardeleană riverbed registered several negative effects in terms of morphologically both vertically and horizontally. We also found that the riverbed downstream of the dam there is a phenomenon called hydraulic paving.

Research on the Sustainable Development of the Bistrita Ardeleana River in Order to Stop the Erosion of the Riverbanks and the Thalweg

“…The hills and the depression are made up of clayey, marly, tuff formations, trapped in a crease system. The catchment area of the river and its tributaries is 650 km 2 , and its elevation varies between 350 m and 1990 m [11,[35][36][37][38]. During winter, this area experiences a climate regime influenced by air currents of polar origin from the west.…”

Research on the Sustainable Development of the Bistrita Ardeleana River through the Resizing of Weirs

“…Two exceptional floods were recorded in the hydrographic basin of the Bistrita Ardeleana River, the first one in 1932 when the hydrometric station Bistrita registered a level of 5.2 m, and the flood registered on 13 May 1970, the level being 3.64 m with a flow of 618 m 3 /sec. [22][23][24][25]. These levels or flows have not been recorded until now due to the construction of the Colibita lake dam, which has the role of mitigating floods in the hydrographic basin of the Bistrita Ardeleana river.…”