The Sieber is a 35 km long, right hand tributary

Tributary

A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...

 of the Oder

Oder (Harz)

The Oder is a 56 km long river in Lower Saxony, Germany. It is a right tributary of the Rhume. Its source is in the Harz mountains, near Sankt Andreasberg. It flows southwest through Bad Lauterberg, Pöhlde and Hattorf am Harz...

 in the Harz mountains of Germany.
It rises at 760 m on the Bruchberg

Bruchberg

At the Bruchberg in the Upper Harz is the second highest mountain in Lower Saxony and the third highest in the Harz mountains in North Germany. It lies between Altenau and Torfhaus in the middle of the Harz National Park. The Bruchberg is more like a plateau and has no real summit...

 massif and flows through Herzberg

Herzberg am Harz

Herzberg am Harz is a town in the Osterode district of Lower Saxony, Germany.- History :Herzberg castle was first mentioned in 1154. The town was part of the state of Brunswick-Grubenhagen, and the castle was for some time used as a residence by the dukes...

 before discharging at Hattorf into the Oder which, in turn, flows into the Rhume

Rhume

The Rhume is a 48 km long river in Lower Saxony, Germany. It is a right tributary of the Leine. Its source is a karstic spring in Rhumspringe, south of the Harz mountain range...

. Its tributaries include the Kulmke

Kulmke

The Kulmke is a tributary of the Sieber near Sieber in the district of Osterode am Harz in the north Germany state of Lower Saxony. It begins at 392 m with the confluence of the Große and Kleine Kulmke. It then flows 2 km in a west-southwesterly direction before discharging into the Sieber....

, Lonau

Lonau (river)

The Lonau is a roughly 3.5 km long tributary of the Sieber. It starts in Lonau, formed by the confluence of the Große and Kleine Lonau. It then flows in a southerly direction to Herzberg am Harz, where it discharges into the Sieber after the Lonau Waterfall....

 and Goldenke

Goldenke

The Goldenke is a 4 kilometre long tributary of the Sieber, north of the village of Sieber in the district of Osterode am Harz in Lower Saxony. It rises at a height of 800 metres in the vicinity of the Hanskühnenburg on the ridge of Auf dem Acker, by the Goldenkerklippe crags...

.

In February 1910, as part of his hydrological research into the Rhumequelle, Karl Thürnau dyed the Sieber tributary of the Eichelbach (Herzberg/Harz) with six kilogrammes of fluorescein

Fluorescein

Fluorescein is a synthetic organic compound available as a dark orange/red powder soluble in water and alcohol. It is widely used as a fluorescent tracer for many applications....

. Three days later, weakly dyed water appeared in the main source of the Rhumequelle. This was confirmed in 1980 by dye tracing

Dye tracing

Dye tracing is tracking and tracing various flows using dye added to the liquid in question. The purpose of tracking may be an analysis of the flow itself, of the transport of something by the flow of the objects that convey the flow...

 carried out by the Geological Survey of Lower Saxony (Niedersächsischen Landesamtes für Bodenforschung). This also indicated links between the Rhumequelle and the Sieber near Hörden

Hörden am Harz

Hörden am Harz is a municipality in the district of Osterode, in Lower Saxony, Germany....

 and the Oder near Scharzfeld

Scharzfeld

Scharzfeld is a village in the borough of Herzberg am Harz in the district of Osterode am Harz in South Lower Saxony, Germany.Scharzfeld lies at a height of about 220 m above sea level and has 1,765 inhabitants ....

.

The construction of a dam

Dam

A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...

 was planned but never realised. As a result the Sieber valley is the only unregulated river valley in the West Harz. The upper Sieber valley is out-of-bounds to vehicle traffic from the Forsthaus Königshof and lies partly within the Harz National Park

Harz National Park

The Harz National Park is a nature reserve in the German federal states of Lower Saxony and Saxony-Anhalt. It comprises large portions of the western Harz mountain range, extending from Herzberg and Bad Lauterberg at the southern edge to Bad Harzburg and Ilsenburg on the northern slopes...

 – the road leads to the B 242

Bundesstraße 242

- Route :The B 242, also known as the Harz High Road , runs right across the Harz mountains in central Germany. From Seesen on the northwestern edge of the Harz near the A 7 motorway it runs through the Upper Harz past Clausthal-Zellerfeld, the High Harz, where it is combined for several kilometres...

 federal road northwest of Sonnenberg

Sonnenberg (Harz)

The Sonnenberg is a ski resort in the Upper Harz surrounded by the Harz National Park. The settlement of the same name located there is part of the borough of Sankt Andreasberg.- Topography :...

.

The river gives its name to the village of Sieber

Sieber (Herzberg am Harz)

Sieber is a village in the borough of Herzberg am Harz in the district of Osterode am Harz in South Lower Saxony .Sieber lies at a height of 340 m above sea level and has about 600 inhabitants . The settlement is spread out over a length of several kilometres in a narrow valley, running from...

in the Sieber valley.