The effects of a presumed climate scenario on the hydrography of the Weser estuary between Bremen (weir) and Robbensudsteert (similar to 10 km downstream of Bremerhaven) were investigated using numerical modeling. The results provide a basic approach for further studies addressing, for example, the utilization and ecology of the Weser estuary and the adjacent areas within the bounds of the winter dike. Morphological aspects are not considered in this paper. A rise in water level at the seaward boundary (high water +70 cm, low water +40 cm) propagates upstream only with some slight deviations. In the climate scenario, the subtidal volume and sublittoral for the section between the weir and Bremerhaven increase by about 6 and 7% respectively, while the tidal prism and eulittoral increase by about 16 and 52% respectively. Residence times of conservative water constituents are prolonged for fixed runoffs. These times also affect the water quality. The location of the upstream boundary of the brackish-water zone is located on average 2 km further upstream for fixed runoffs, possibly causing problems with marsh irrigation.
