The research of hydrodynamic processes in rehabilitating rivers of Lithuania
2016
Baublys, R., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania) | Dumbrauskas, A., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania) | Geguzis, R., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania)
From the 1920s through the 90s, most streams in Lithuania were channelized. Channelization is the deepening, clearing and straightening of meandering streambeds resulting increase of water flow velocity and the rate at which water drained away from agricultural land. Channelized and straightened streams have better hydrodynamic parameters and different morphological properties, but at the same time that caused more unfavourable conditions for natural biodiversity along stream beds and banks reducing the amount of vegetation which means less food and cover for wildlife. Most of West European countries have a good practice for restoring of channelized rivers. This experience is quite new in Lithuania and starting with pilot projects. The most important purpose of these projects is to choose the appropriate restoration measures and evaluate their effectiveness under conditions of dense channel network and tile drainage systems in Lithuania. Two channelized streams, selected for a pilot project are discussed in this paper. The main purpose is to restore stream meandering with minimal efforts allocating artificial obstructions at a right place and reach the necessary stream velocities to initiate the stream bed deformation. For this purpose detailed channel geometry data were collected and 1D hydrodynamic model applied. The results of different scenarios revealed that installed obstructions can accelerate deformations processes initiate the meandering process and at the same time it will not have any significant effect on the agricultural land along restored stream.
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