Mura - Austria Hydro Power Plant
The natural course of the Mura River has been significantly altered by a chain of more than 30 hydro power plants (HPP), mostly built after 1974 along its upper course in the Austrian high alpine hinterland, the majority of which are still in operation today.
The map shows all existing hydropower plants in Austria and all planned hydropower plants in Slovenia.
With the strong damming of the upper and middle river in Austria, the Mura’s water flow lost stability on its way through Slovenia. This had considerable impact on the water level itself and the level of underground water, but what is particularly problematic is the deepening of the river bed, which proceeded rapidly. According to some measurements, it dropped by more than a meter, which accelerated erosion, lowered underground water levels, cut off meanders, reduced biotic diversity and thus had an impact on agriculture and arable farming. By regulating groundwater levels and microclimate, the river is an important contributor to soil fertility in the fields along its course.
The impact of the construction of a chain of HPPs has increased groundwater fluctuations. In addition to seasonal stresses and fluctuations, there is the added stress that water is retained behind dams during the dry season, precisely when it is most needed for agriculture. At the same time, high flows are amplified during periods of peak rainfall, further increasing the velocity and constriction of the river so that groundwater cannot recharge. All this is a consequence of the strong upstream impoundment, which we cannot observe in the case of the Vjosa.
Today there are still no HPPs on the lower reaches of the Mura River in Slovenia, Croatia and Hungary (except for a small power plant at Ceršak. However, there are plans to build a number of HPPs as far as the river mouth, where Mura becomes Drava in Legrad (Croatia).
In 2019 the Slovenian Government halted all preparations for changes to the National Spatial Plan that would have included plans to construct an HPP on the Mura River at Hrastje-Mota.
The Mura and the wider biosphere zone are home to 200 species of birds, 600 species of plants, 1,200 species of butterflies, 1,200 species of beetles, 60 species of fish, 30 species of mammals, 10 species of reptiles, 15 species of amphibians, 95 species of snails and mussels, and many other species. Some of these are so rare and valuable that they have been protected.
The illustration shows the European mudminnow (Umbra krameri), which is listed as a protected species in Slovenia. The causes of its endangerment are draining of wetlands, regulation of watercourses and probably spraying of agricultural land.
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