Upper Harz Water Regale

The Upper Harz Water Regale (German: Oberharzer Wasserregal, pronounced [ˌoːbɐhaːɐ̯tsɐ ˈvasɐʁeɡaːl]) is a system of dams, reservoirs, ditches and other structures, much of which was built from the 16th to 19th centuries to divert and store the water that drove the water wheels of the mines in the Upper Harz region of Germany. The term regale, here, refers to the granting of royal privileges or rights (droit de régale) in this case to permit the use of water for mining operations in the Harz mountains of Germany.

The Upper Harz Water Regale is one of the largest and most important historic mining water management systems in the world. The facilities developed for the generation of water power have been placed under protection since 1978 as cultural monuments. The majority are still used, albeit nowadays their purpose is primarily to support rural conservation (the preservation of a historic cultural landscape), nature conservation, tourism and swimming. From a water management perspective, several of the reservoirs still play a role in flood protection and the supply of drinking water. On 31 July 2010 the Regale was declared a UNESCO World Heritage Site affiliated with the Mines of Rammelsberg and the Historic Town of Goslar because of its importance in the development of mining techniques and testimony to the medieval history of ore mining.

The water system covers an area of roughly 200 square kilometres (77 sq mi) within the Lower Saxon part of the Harz, the majority of structures being found in the vicinity of Clausthal-Zellerfeld, Hahnenklee, Sankt Andreasberg, Buntenbock, Wildemann, Lautenthal, Schulenberg, Altenau and Torfhaus.

Regale in this context means a royal prerogative. Through the so-called Bergregal, or "mining rights", the monarch granted the right to mine and, through the Wasserregal, he granted the right to use local water supplies for the purpose of mining. Other water users, particularly mill owners, had a lower priority. This 'water regale' or 'right to use water' was part of the overall Bergfreiheit or mining rights that were valid in Lower Saxony until the 1960s.

In German, the term Oberharzer Wasserwirtschaft ("Upper Harz Water Management") has also been frequently used to refer to these historic facilities. But this is not precise enough, because in the last hundred years an intensive, modern water management system has been put in place in the Upper Harz in the form of a number of new dams and their associated structures and ditches.

The Upper Harz was once one of the most important mining regions in Germany. The major products of its mines were silver, copper, lead, iron and, from the 19th century, zinc as well. The main source of income, however, was silver. From the 16th to the middle of the 19th centuries about 40–50% of the entire German silver production originated in the Upper Harz. The taxes raised from this contributed significantly to the revenue of the royal houses in Hanover and Brunswick-Wolfenbüttel and helped to secure their positions of power and influence within the Holy Roman Empire.

Its lucrativeness justified a high commitment in terms of investment and effort. Hereby the Upper Harz mining industry produced a considerable number of innovations and inventions, including such important advances as the man engine, the water-column engine (Wassersäulenmaschine) and the wire cable.

Mining becomes a very energy-intensive activity as soon as excavation extends any significant distance underground. In the Upper Harz, vein mining (Gangerzbergbau) was the main form of extraction, with excavation following the near-vertical lodes straight down into the earth. Only a few metres down the ingress of water increased the difficulty of excavation considerably. Initially it was mopped up using men standing on ladders, the so-called Wasserknechten ("water servants"), with their leather buckets. Later, the introduction of horses and whims (Göpel) enabled larger quantities of water to be lifted. But horses were expensive and had to be changed every few hours. As a result, mines – particularly the richer, deeper ones – started to use hydropower systems, able to work continuously, 24 hours a day. To do this, streams were diverted onto water wheels that drove reciprocating pumps in order to raise water from greater depths and in greater quantities. The principle was to raise water with water.