Dredging needed to desilt the River Ems

Ebb in the River Ems. Credit: Masterplan Ems 2050
Ebb in the River Ems. Credit: Masterplan Ems 2050

The River Ems in Germany is struggling with silt contamination. Through changes in the river’s course – straightening and deepening – as well as the disappearance of natural silt accumulation areas, the ratio of ebb and flow duration in the Ems has shifted considerably. This means more sediment is carried into the Ems than the ebb removes.

The federal state of Lower Saxony has therefore designed the Masterplan Ems 2050 to counter this problem and future proof the river as part of its economical infrastructure. This includes not only measures against the siltation but also the creation of habitats and improving the Ems as waterway.

One initial measure to resolve the silt problem is planned to commence at the beginning of next year. Through flexible tidal control of the gates of the Ems barrier the above described effect is countered.

A second measure is the creation of a tidal polder in Coldemüntje. Dredging of about 430,000 m3 will be necessary to create a wetland habitat. Two thirds of the dredged material will be used to reclaim land or improve the nearby dyke of Westoverledingen, with discussions ongoing about how to use the remaining 115,000 m3. The current favoured solution from locals and politicians is to use the material to top up farm land, with discussions with farmers being underway.

The Masterplan Ems 2050 reads as follows, “According to measurements by the coastal research station of the Lower Saxony State Organisation for Water Management, Coast, and Nature Conservation (NLWKN), the concentration of sediment in the water of the Ems is 100- to 1,000-times that in the neighbouring rivers of Elbe and Weser.”

The NLWKN has found another anomaly of the Ems, noting, “Despite the very high sediment content, the mixture remains fluid but behaves differently than water, and is not habitable for wildlife. This ‘system state’ of the river is very rare, according to the coastal research station, and international knowledge of this topic remains ‘highly incomplete’.”