In Uiterwaarden, Joan Reinders focuses on the river's floodplains, a dynamic and ever-changing part of the water cycle. This composition explores the natural process of the uiterwaarden—the floodplains—that are formed and shaped by the rising and falling waters. Uiterwaarden delves into the relationship between water and land, illustrating how the land is shaped by water’s movements and how this ecosystem is vital for both nature and human life. Performed by Stefan and Martijn Blaak with the Millennium Jazz Orchestra, this piece blends classical and jazz elements to represent the flowing, shifting nature of the floodplains, with moments of tranquility and dynamic change. As with other sections of Water, Uiterwaarden is introduced by video segments featuring experts like Peter Kuipers Munneke, Li An Phoa, and Peter Glas, who discuss the ecological importance of the floodplains in water management and nature conservation.