The presence of the river is one of the main factors which create the city. It has a positive effect on climate and human well-being, promotes biodiversity and recreation and improves quality of people life. The Warta River is an important compositional and functional element in Poznan. The valley area of the river within the administrative boundaries of city is subject to a strong human impact. Decline in the economic importance of the river caused a reversal of the city from her. This unfavorable phenomenon continues to present days. Inadequate management of urban riverside areas prevents the use of their potential. More and more devices and hydraulic structures are dangerous for ecosystems in the river. One of the ways of their pro...