Gewässerkennzahl


The Gewässerkennzahl or "waterbody index number/waterbody number" is an identifier with which all watercourses in Germany are numbered, together with their catchments and precipitation areas. It is also referred to as a Gebietskennzahl or "basin number". A Gewässerkennzahl may have up to 13 figures. Basins normally are only defined up to seven figures. For a more detailed subdivision, the Gewässerkennzahl may be enlarged by ten more figures. Only that enlarged version is called Fließgewässerkennziffer. The Gewässerkennzahlen are defined by the environment offices of the states.

History

In order to have comparable values and usable data across the state of Germany, the Federal and State Water Authorities agreed in December 1970 to create a unified system for hydrological work on certain important rivers and their above-ground catchment areas and to issue them with index numbers. Linked to that was the establishment of the size and boundaries of their catchment areas.

Principle

Every waterbody and its catchment area was given a waterbody number in such a way that it could be clearly identified. The waterbody numbers are built in hierarchical fashion so that, based on the number, the next river system of the waterbody can be deduced.

Scheme

At first the course of water has to be defined from source to mouth. Then the four major tributaries are identified. They are marked by even figures in downstream sequence, "-2, -4, -6, -8". This way, the course is divided into five sections, which are marked by odd figures, "-1, -3, -5, -7, -9". A number with an even end-digit is the number of a whole watercourse, while a number with an odd end-digit is the number of a section. Lowest sections are always given a nine, even if not all figures between one and nine have been used. In the next step of numbering, each section defined by the first step is dealt in the same way, selecting four major tributaries and marking five sections.

Lakes

Lakes are integrated as a part of the watercourse formed by their main tributary and their outlet.

Coastal regions

For coastal regions, the scheme of numbering was altered in different ways by different states:
  • Lower Saxony left the rule of using only odd numbers for sections. Nevertheless, bay as dependent waterbodies got even numbers.
  • Mecklenburg-Vorpommern stuck to using even numbers for important rivers and odd numbers for – here coastal – sections in between. But the course of the coast was defined in a way, that in two straits different third figures were used for their two banks.

Waterbodies without a Gewässerkennzahl

Some waterbodies indexed under this classification system have un-indexed headstreams or lateral tributaries in the form of very small streams or ditches. If such an unclassified waterbody is relevant for the water management of the region, it may be given a number within the local classification system of the regional Wasser- und Bodenverband.

Catchment areas

The numbers for a watercourse and its catchment area are thus identical. If a river has subsidiary watercourses, an additional figure is allocated to its index number for each further branch. So in theory even a rivulet could be allocated its own catchment. In practice, catchment numbering for water sources below the level of streams is not used.
Catchment areas are thus distinguished by a number with up to a maximum of seven digits. Watercourse index numbers, by contrast, may have up to 13 digits in order to be able to classify all their tributaries and headstreams; although in practice only 10 digits are used.

Main river systems

The first digit of the number indicates which major river basin the waterbody belongs to, as follows:
The second and subsequent digits of the index number represent further subdivisions of the river and its catchment area.

Example

The Heusiepen stream in Remscheid has waterbody number 27366462. This can be decoded as follows:

Waterbody index numbers

Listed below are all the rivers with up to a three-figure index number, and some rivers with four-figure numbers above a length of 50 km.

1 Danube

NumberNameLength
Catchment area
1Danube 2857817,000
112Lauchert60.3456
114Iller 1472,147
1158Günz55710
116Mindel81962
1172Brenz52880
118Wörnitz1321,686
12Lech2643,926
122Archbach 10145
124Vils36198
126Wertach1501,260
128Lechkanal1419
132Friedberger Ach 100598
134Paar1341,632
136Abens721020
138Altmühl2342,251
14Naab 1655,432
142Haidenaab60714
144Pfreimd56595
146Schwarzach80822
148Vils781,100
152Left branch of Danube in Regensburg3,62.881
1522Regen 1912,953
154Pfatter37262
156Große Laber75407
158Kinsach–Ferchenbach38317
16Isar2958,370
162Loisach113954
164Amper 2093,248
166Mittlerer Isarkanal 64,71,147
168Plattlinger Mühlbach 75345
172Hengersberger Ohe 34198
174Vils 1101,445
176Große Ohe 46176
178Ilz62850
18Inn51726,130
182Mangfall 581,099
184Alz 1502,197
186Salzach2256,700
188Rott1091,205
1914Große Mühl71560

2 Rhine

NumberNameLength
Catchment area
2Rhine1239185,300
215Lake of Constance: Obersee
5,386
217Lake of Constance: Untersee; also including the section of the Rhine down to its confluence with the Thur
5,386
2152Argen with Obere Argen73655
2198Wutach911,140
232Wiese55458
2338Elz1211,539
234Kinzig931,406
236Murg80466
238Neckar36213,934
2382Fils63699
2384Enz 1062,229
2386Kocher 1691,960
2388Jagst1901,838
24Main 57227,292
242Regnitz 1877,523
2422Pegnitz 1271,230
244Franconian Saale1392,765
246Tauber1291,810
248Nidda901,942
252Selz61389
254Nahe1254,067
256Wisper30209
258Lahn2465,925
26Moselle54428,286
262Sauer1734,259
264Saar2357,431
2642Blies991,960
2646Prims91737
2648Nied 1141,370
266Kyll142845
268Alf52358
2716Wied102771
2718Ahr85897
272Sieg1552,857
2736Wupper116.5813
274Erft1071,838
276Ruhr2194,485
2772Emscher83775
278Lippe2204,888
28Meuse 87433,000
282Rur1652,361
284Schwalm35268
286Niers1181,381

3 Ems

Here some three-figure numbers are not listed.
NumberNameLength
Catchment area
3Ems37113,160
316Hessel39213
318Bever39,5217
32Werse67762
332Münstersche Aa43172
34Große Aa25922
36Hase1703,086
38Leda 751.917
388Jümme 94450
394Oldersumer Sieltief 26235
397Dollard
3974Dollard
398Knockster Tief 311351
399Outer mouth of Ems River

4 Weser

NumberNameLength
Catchment area
4Weser 45141,094
41Werra3004,497
412Hasel26331
414Ulster57421
416Hörsel55784
418Wehre36452
42Fulda2216,947
422Fliede22271
424Schlitz (river) 43315
426Haune67500
428Eder1763,361
432Schede1349
434Nieme1740
436Schwülme29290
438Reiherbach10.535
44Diemel1111.762
442Hoppecke3592
444Twiste41447
446Warme33157
448Esse28192
452Nethe50460
454Lenne24125
456Emmer62535
458Exter26109
46Werre721,485
462Bega44377
464Aa 44377
466Else35416
468Rehmerloh-Mennighüffer Mühlenbach1671
472Bückeburger Aue39173
474Gehle27163
478Steinhuder Meerbach29356
476Große Aue851,522
48Aller26015,744
482Oker1281,834
484Fuhse98918
486Örtze 70760
488Leine2816,512
492Ochtum 45917
494Wümme1181.585
496Hunte1892,785
498Lune43383

5 Elbe

NumberNameLength
Catchment area
5Elbe1094148,268
52Vltava 43028,090
5281Mže1031,829
532Ohře3165,614
538Black Elster1795,705
54Mulde 3147,400
541Zwickau Mulde1672,352
542Freiberg Mulde1242,981
549Vereinigte Mulde 1477,400, own 2,067
56Saale41323,719
562Loquitz34364
564Unstrut1926,364
566White Elster2575,154
568Bode1693,229
572Nuthe39509
574Ehle40?
576Ohre1031.503
578Tanger33480
58Havel33423,858
582Spree40010.100
584Nuthe521,935
586Plane57639
588Rhin1291,780
592Elde2082,990
5934Jeetzel731.928
594Ilmenau1072,852
5956Alster56581
5958Este62364
596Lühe 44216
5974Stör781.781
598Oste1531,711

Literature

  • Landesamt für Wasser und Abfall Nordrhein-Westfalen : ''Gebietsbezeichnung und Verzeichnis der Gewässer in Nordrhein-Westfalen''