Middle Danube
Demonstration Site 2
Sződliget
Hungary
About the Site
The Middle Danube Demonstration Site is located at river km 1675, upstream of Budapest, adjacent to the town of Sződliget on the famed and highly scenic "Danube Bend". Work in this section will focus on groyne optimization. Groynes are shore protection structures built perpendicular to the river bank or coastline, that limit longshore drift and trap sediment and materials.
This highly touristic region of peaks and picturesque river towns to the north of Budapest, is the most well-known bend on the Danube. However it is only one of several such sites where the river changes its course significantly en route to the Black Sea.
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Environmental Pressures
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In this section, river regulations have resulted in loss of habitats and side branches. The river is channelized i.e., has been deepened and straightened through human intervention, and has a low structural diversity. The groynes in the site have been built on the right-hand side littoral (shore side) zone as a river regulation infrastructure. Between the groynes sedimentation and siltation occurs.
These island-like structures can act as stepping stones for semi-aquatic habitats. While these form important components within the Danube-wide habitat corridor, the gravel-dominated littoral zone has turned into slow-flowing or standing water with mud, and the dynamic character of the river has been lost. In the long-term, ongoing sedimentation will worsen the situation.
Proposed Activities
This Demonstration Site will implement in the field the first ecological groyne optimization in Hungary. The design of this site has been elaborated within the DANUBEparks CONNCTED project. The hydrological models confirm the sustainability of the measure, with technical planning already approved by the responsible authorities.
The following series of measures will be implemented:
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Groyne opening will form a new side channel with increased velocity
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The re-dynamization will improve structural diversity in an area of ~ 50 ha, increase biodiversity, protect shallow waters against wave stress and provide a nursery for rheophilic species (aquatic species that prefers to live in fast-moving water e.g., common nase and the Danube bleak)
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DANUBE4all will closely cooperate with the local communities, inhabitants, SMEs, and stakeholders to optimise the final design, strengthening participation before, during and after implementation of the measures e.g., by involving Citizen Science in monitoring programs
