Grubebach

Grubebach ( Bokel-Mastholter main canal )
The Bokel-Mastholter main canal south of Rietberg
Data
Water code	EN : 3116
location	North Rhine-Westphalia , Germany
River system	Ems
source	In the Ostland district of Delbrück 51 ° 47 ′ 58 ″  N , 8 ° 37 ′ 15 ″  E
Source height	103  m above sea level NN
muzzle	Northwest of Rietberg in the Ems Coordinates: 51 ° 49 '16 "  N , 8 ° 21' 43"  E 51 ° 49 '16 "  N , 8 ° 21' 43"  E
Mouth height	approx.  72  m above sea level NN
Height difference	approx. 31 m
Bottom slope	approx. 1.4 ‰
length	22.2 km
Catchment area	99.93 km²
Left tributaries	Fortbach
Right tributaries	Hoppenmeer, Lannertbach
Communities	Delbrück and Rietberg

The Grubebach , known in the lower reaches as the Bokel-Mastholter Hauptkanal , is an orographically left tributary of the Ems in North Rhine-Westphalia , Germany . It has a length of 22.2 km. The Grubebach lowland naturally belongs to the East Munsterland sands within the Ems sand plain .

River course

The Grubebach rises in the Ostland district of Delbrück as a lowland brook at a height of approx. 104 meters. After just a few meters, it takes up a tributary with its own source pot and then flows in a westerly direction through the Delbrücker Land . The Grubebach flows consistently over rural areas south of the village of Lippling and passes under the federal highway 64 north of Nordhagen . The water then runs north past Westenholz . After the 6.8-kilometer-long Hoppenmeer , flowing in from Schöning , was recorded on the right, the Grubebach changes its name to Bokel-Mastholter Main Canal due to its canal-like expansion in the lower reaches. In fact, however, it is still a natural flowing water.

The main canal continues its course in the area of ​​the city of Rietberg , flows south past Rietberg and then passes the district of Bokel . To the north of Bokel, the Lannertbach stream is added to the right and shortly thereafter the Fortbach stream flowing to the left . The main canal flows into the Ems not far from these tributaries .

The course of the water overcomes a height difference of 31 meters, resulting in a mean bed gradient of 1.4 ‰.

Characteristic

About the pit Bach or the Bokel-Mastholter main channel are Meliorationswässer from the Mastholter lowland discharged to the Ems out. Above all, these tributaries make the water the largest left-hand tributary of the Ems in its upper reaches.

The Grubebach runs just north of the Ems-Rhine watershed . For example, the Schwarze Graben, which flows into the Glenne, rises just a few meters south of its course; a system of ditches connects the river systems .

history

After the end of the last Ice Age, the bed of the Grubebach rose up to three meters above the surrounding floodplain level due to the interaction of deep erosion and sedimentation , especially in the lowland area south of Rietberg . Floods regularly occurred during high tides, as the water of the brook could pour unhindered into the lowlands in the event of the bank wall breaking.

For this reason, a drainage project has been pushed forward since the middle of the 19th century. The bed of the Grubebach was deepened in the area of ​​Rietberg and Bokel and put into the canal-like state in which it is to this day. As a result, there is currently a conflict between the goals of flood protection and the near-natural development of water bodies, which is the aim of the Water Framework Directive .

In July 2002 there was massive fish death in the Bokel-Mastholter main canal after a major fire in the Rietberg industrial area, which killed around 90 percent of the fish fauna native to the water. The reason was contaminated extinguishing foam that flowed in via the trench systems , which in the Bokel area piled several meters high on the surface of the water. In the meantime, however, the stocks have largely recovered. In response to this event, the local sewer system was fundamentally revised.

Individual evidence

1. ↑ ^{a b} German basic map 1: 5000
2. ↑ ^{a b} Water directory of the State Office for Nature, Environment and Consumer Protection North Rhine-Westphalia (PDF; 1.1 MB)
3. ^ Heimatverein Rietberg: On the geology of the Westphalian Bight (PDF). (No longer available online.) Formerly in the original ; Retrieved April 26, 2014 .  ( Page no longer available , search in web archives )  
4. ↑ Report on rietberg.de for renovation project