Uncertainty is a frequent obstacle in decision making process, therefore understanding its sources might facilitate this process and increase its effectiveness. The objective of the paper is to identify the sources of uncertainty in planning in water management, which have been revealed and identified by carrying out the process of developing cognitive scenarios in the Klimat project (POIG.01.03.01-14-011/08). The paper discusses scenarios for development of water management and the development process thereof in the Klimat project. Selection of literature is presented, showcasing other projects in which scenario analyses of this type from around the world have been performed. A method of formulating development scenarios in water economy is presented, along with its results, which reveal the sources of uncertainties in water management planning.