The Črneče Bay or Dravograd Lake belongs to the rare intermittent secondary marsh ecosystems with a great diversity of animal and plant species and their habitats. The diversity of animal and plant species and their marsh habitats place it among the most important wetlands in Slovenia in terms of nature protection. This rare ecosystem is the habitat for endangered animal and plant species, and the area is also listed among the Natura 2000 network of nature protection areas. With reconstruction works and removal of sediments in the Črneče Bay, we provide for a favourable conservation state of the bay and prevent parts of it from being deprived of water during periods of low levels in the Drava.
As part of the ecological rehabilitation and removal of sediments in the reservoirs of hydro power plants, also envisaged was the development of the Tilkova mlaka Bay in the reservoir of the Vuhred Hydro Power Plant. The area of the Tilkova mlaka Bay was heavily silted, which was caused by the left tributary called Suhi potok, which carried large quantities of gravel to the bay during heavy rainfall, and the turbidity was also caused by the transport of floating particles in the Drava and sediment which settled in the place where the river widens. During the operation phase of the Vuhred Hydro Power Plant, the water level fluctuates by around one metre. Before the reconstruction, the eastern part of Tilkova mlaka was completely dry, with only the western part covered in water. The dry part in the east of the bay did not yet show the signs of extensive growth, and it emitted an unpleasant smell during low water levels. The western part of the bay is rich in aquatic plants and, according to the data from the Radlje ob Dravi fishing club, provides numerous fish species with spawning grounds. By redeveloping the dry part of the bay, we also prevented the danger of fish fatalities during sudden changes in the water level, when fish would be left stranded.
The ecological rehabilitation of the Vas Bay included the implementation of measures which, in addition to facilitating the removal of sediment from the bay, will help to reduce the volume of sediment deposited in this area in the future. The broader area, which also includes the Vas Bay, is protected as an exceptionally important habitat of numerous protected and endangered species with a Decree on special protection areas (Natura 2000 areas).
The objective of the rehabilitation was to improve the functionality of the energy facility, while taking measures acceptable from the aspect of nature protection. The envisaged measures must at least preserve the existing state of flora and fauna in the area. Under the condition of appropriate use, the planned measures contribute to maintaining the nature protection objectives.
In front of the dam structure of the Vuhred Hydro Power Plant, on the left bank in the immediate vicinity of the left wing wall of the dam structure, we have removed the sediment which had been deposited during increased flows directly on the left side, in front of the dam structure, causing the sluice gates of the first spillway to become silted and endangering the undisturbed operation of the power plant.
The reservoir of the Mariborski otok Hydro Power plant is an attractive area for recreation. In the past decade, we have successfully developed various tourism and recreation spots on the lake. The deepened mooring spots and bottoms for boats and tourist facilities, development of the mouth of the tributary and construction of artificial islands maintain and expand the tourism development potential of the lake. In addition to all the other measures, possibilities for the utilisation of the water body for tourism and recreation have also been considered, as in the development of the Ptuj Lake.
The Ptuj Lake is an important refuge for migratory birds and, in particular, rare and endangered bird species, which have found a replacement habitat there. The lake is also an attractive area for recreation. Dravske elektrarne Maribor has conceptualised the prudent preservation of its natural features with the pilot project of the renaturation of the shore of the Ptuj Lake.
In cooperation with the association DOPPS-Birdlife Slovenia, in 2004 we implemented an important nature protection project - a large nesting island for the common tern. As a result of the good cooperation between Dravske elektrarne Maribor and DOPPS, another two artificial islands, covered in gravel, were created on the Ptuj Lake in 2014 to provide nesting grounds for the common tern. The islands contribute to the preservation of the common tern, a migratory bird of the order of Charadriiformes, which nests only on open areas without vegetation, in particular on gravelly river islands. The common tern used to nest on point bars of the Drava, but the changed dynamic of the river flow resulted in these overgrowing and, consequently, the birds moving to other areas. In 2004, only two colonies of the common tern nested in Slovenia, and the critical shortage of suitable nesting grounds could have resulted in the complete disappearance of the local population of the bird in the future. The newly constructed islands, as part of the project, return the habitat to the birds as they provide conditions equal to those found on natural point bars.
The flow of the Drava River carries various wood debris and driftwood, which may, at high discharge rates, cause the blockage of the guide vanes of turbines and, consequently, reduction or even stoppage of the production of electricity, while also impacting the ecological state of the water in the lower course of the river. In accordance with the concession contract for the exploitation of the Drava and corporate social and environmental responsibility on all hydro power plants, we make sure that driftwood and other debris is regularly removed. As part of their infrastructure, all hydro power plants have temporary depots for driftwood and other debris, which temporarily (until it is removed) stores the material taken from the river by the company's own staff. By doing so, we enable optimal utilisation of the waterpower potential for the production of electricity and positively contribute to the undisturbed flow of the Drava. The removed driftwood and other debris is appropriately sorted in accordance with the requirements of the legislation regulating removal of waste. Debris of organic origin is treated as raw material for further processing – after processing, the ground-up material is used as humus. The removal of driftwood and other debris represents a very important activity in the company's operations both from the operational and the security aspects (water flow, reducing flood risk, removal of waste).
