Łukasz Pieron, Krzysztof Woś, Krzysztof Wrzosek
Retention reservoirs are one of the basic elements of water management. Multifunctional, they are used for flood protection, drought prevention and other purposes. Water reservoirs can also play a fundamental role in improving navigability on the lower section of the Vistula River from the Włocławek barrage to the mouth of the Gdansk Bay. Their implementation is a determinant for the possibility of restoring the economic role of the river in question. Therefore, the purpose of this research was to determine the current navigation conditions and the state of the regulatory buildings on the Lower Vistula. The investments necessary to achieve international parameters of the waterway were also determined, together with the calculation of financial benefits related to their implementation. This was possible based on the conducted bathymetric measurements, spatial analyses, economic calculations and queries of the obtained studies. It was established that fairway depths of 1.4 m are ensured for 180 days per year on average. On the other hand, the construction of five barrages (Siarzewo, Solec Kujawski, Chełmno, Grudziądz and Gniew) will make it possible to achieve at least a navigability class IV (international) on the section of the Vistula River waterway. In addition, the barrages will enable the retention of 1.2 billion m3 of water and will be associated with financial benefits such as shipping use, flood protection and counteracting the effects of drought. On this account, annual revenues may amount to approximately PLN 3.5 billion. This shows that the construction of the reservoirs is profitable, and the proposed solutions should be implemented in the context of sustainable water management and adaptation to climate change.