	The Stever is a tributary of the Lippe which is fed by water out of the Dortmund-Ems Canal and has a huge meaning for drinking water supply for the northern Ruhr region. To balance the whole system the Stever – after being fed out of the canal in Senden – is backed-up in two water reservoirs (Talsperre Hullern and Halterner Stausee) of 32 Mio. m³ capacity. Two-thirds of the Stever flow is discharged downstream; one-third is used by the drinking water supplier Gelsenwasser AG for drinking water processing via soil infiltration from groundwater wells (of all together approximately 129 Mio. m³/year). Additionally the municipal utilities Stadtwerke Münster use water from the Dortmund-Ems Canal to supply the groundwater wells for drinking water processing. In total, via several water works annually 250 Mio. m³ of water are transported in pipework from the Ruhr to the area at the canals. 