About 80 percent of inland water transport in Poland is based on the Odra river. The remaining 20 percent works on the Wisła-Odra waterway, The lower Wisła river on the stretch from Płock to Gdańsk and the Włocławek water reservoir as well as partly on the upper part of Wisła river between Oświęcim and Kraków. The largest ship trafficking is performed between Szczecin and the inland Western European ports. There is not a great deal of transport between Szczecin and the ports situated down-stream near the Wisła. Inland connections are facilitated to the Russian port of Kaliningrad situated on the Zalew Wiślany.