The Weser Estuary By DIETRICH LANGE, HELMUT MÜLLER, FRIEDERIKE PIECHOTTA and REINER SCHUBERT C o n t e n t s 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275 2. Geomorphology of the Weser Estuary . . . . . . . . . . . . . . . . . . . . . . . . . . . 277 3. Hydrological Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280 4. Measures for the Improvement of the Weser Estuary . . . . . . . . . . . . . . . . . . . 285 5. Maintenance of the Fairways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285 6. Monitoring and Analysis of the Weser Estuary . . . . . . . . . . . . . . . . . . . . . . 286 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287 1. I n t r o d u c t i o n After the Elbe, the Weser is the second-largest river in Germany discharging into the North Sea. Its origin is the confluence of the rivers Werra and Fulda at Hannoversch-Münden. After cutting through low mountain ranges it flows in northerly direction through the Northern German lowlands. It can be subdivided into the sections Upper Weser (Oberweser: Hann. Münden – Minden), Middle Weser (Mittelweser: Minden – Bremen), Lower Weser (Unterweser: Bremen – Bremerhaven) and Outer Weser (Außenweser: Bremerhaven – open sea) (Fig. 1). The barrage in Bremen-Hemelingen defines the tidal boundary. While the bottom of the Upper Weser is characterized by rubble sediment of the overlying rock, the Middle Weser carries the gravel sediment of the lowlands. Bottom sediments of the Lower and Outer Weser consist mainly of medium and fine sands. The entire length of the Weser is classified as a federal waterway (Bundeswasserstraße) for the transport of goods by barges and sea-going vessels. The ‘Mittellandkanal’, an artificial inland waterway intersecting the Weser near Minden, connects the waterway Weser in East- West-direction with the rivers Elbe, Ems and Rhine. Inland navigation vessels can directly go from the Lower Weser to the Ems, via the river Hunte and the ‘Coastal Canal (Küstenka- nal)’. Sea-going vessels can call on the Lower Weser ports Bremen and Bremerhaven (City of Bremen) as well as Nordenham and Brake (Lower Saxony). Bremerhaven is the site of one of the most important Container terminals of the world. After completing construction works in 2008, the river-parallel container quay has an over- all length of 5.4 km. Improvement and deepening of the navigation channel and the most modern quay equipment enable the currently largest container ships to call on Bremer- haven. Turnover figures in Bremen/Bremerhaven had two-digit growth rates during the past few years and amounted to approximately 5,000,000 TEU in 2007. In addition to containers, cars are the most important cargo handled in Bremerhaven. In 2007, a turnover of 2,000,000 cars has been exceeded the first time. The privately managed port of Nordenham excels in bulk goods. Mainly coal is tran- shipped here (import); iron and steel are growing factors. The growth rate of exported goods amounted to 8 % in the years 1998–2005. The port of Brake is a hub for the import and export of animal feed and grain. A strong 275 Die Küste, 74 ICCE (2008), 275-287