|Seat||Hildesheim , Lower Saxony|
|Number of employees||> 240 including trainees (2018)|
|sales||EUR 58.5 million (2018)|
|Branch||Drinking water supplier, dam operator, flood protection|
The Harzwasserwerke GmbH (HWW) is a Lower Saxon water utilities and dam operators with the main tasks of drinking water supply , power generation, flood control and maintenance of the Upper Harz Water Regale . In six dams in the Lower Saxon part of the Harz Mountains built between 1930 and 1969 , water is stored, processed into drinking water in three waterworks and distributed over large parts of Lower Saxony via a pipeline system. The system is supplemented by four groundwater works located in the north German plain . With an output of 91.3 million m³ per year (as of 2016), they are the largest water supplier in Lower Saxony.
The Harz waterworks were then founded in 1928 under the sign of some floods that also triggered a typhus epidemic in the Harz foreland. At that time they were called Harzwasserwerke of the Province of Hanover . The Sösetalsperre was the first structure to go into operation in 1931 . An almost 200 km long steel pipeline with a nominal diameter (DN) of 450 to 800 mm was laid from the local waterworks to Bremen and parts of the city of Bremen were supplied with drinking water; the city of Hildesheim has also been getting drinking water from the Sösetalsperre since 1934. The Oder Reservoir was also built in the 1930s, although it only serves to protect against floods and to generate electricity. In 1944 the Eckertalsperre was completed, which mainly supplies the city of Wolfsburg via a nearly 80 km long pipeline. In 1956 the Okertalsperre was completed , which with its impressive arch dam is the most spectacular structure of the Harz waterworks. The Innerste Dam (completed in 1966) and the Granetalsperre (1969) are the youngest dam structures.
By means of a tunnel system built in the early 1970s, water from the Radau and the Okertalsperre can be fed to the Granetalsperre in a free gradient. In addition, a pump pipeline was built in the early 1980s to transfer water from the Innerste dam into the Grane dam. In this way, large amounts of potential drinking water can be collected and stored in the Granetalsperre, from where it is then also treated and routed via another pipeline system towards Braunschweig, Hildesheim and Hanover. In 1979, another line with a pipe diameter of 800–900 mm was laid from the Sösetalsperre to Göttingen.
The groundwater works Schneeren (1960), Ristedt (1963), Ramlingen (1964) and Liebenau (1977) supplement the drinking water supply and take over the supply primarily in the north-west of the supply area.
In 1991 the Harzwasserwerke undertook a contract with its owner at the time, the State of Lower Saxony, to take over, operate and maintain the facilities of the Upper Harz Water Regale cultural monument . This special task in the area of the preservation of industrial monuments costs the Harzwasserwerke a seven-figure amount every year, which has to be earned through the sale of drinking water.
After the state of Lower Saxony was founded in 1946, the Harz waterworks were called "Harzwasserwerke des Landes Niedersachsen" and formed an institution under public law with the sole owner of the state of Lower Saxony. In 1996 the country carried out a privatization under the then Prime Minister Gerhard Schröder and sold the facility for 220 million DM to a consortium of energy suppliers and customers of the Harzwasserwerke. Since then the name has been "Harzwasserwerke GmbH".
The constellation that more than half of the owners are also customers of the HWW does not make it easy for Harzwasserwerke: Customers expect low drinking water prices and owners high returns. These two requirements contradict each other and are difficult to meet at the same time.
HWW achieves 95% of the sales revenue with the sale of drinking water, whereby it is not sold to the end customer, but always only up to the city limits to the local utility companies. The largest customers today are the municipal utilities of Braunschweig , Göttingen , Bremen , Hanover and Hildesheim . Customers are also many smaller municipalities and water boards that are close to the pipeline system.
5% of sales are generated through power generation. There are hydropower plants in all dams. In addition, there are turbines in some pipelines for the drinking water supply, which convert the gradient between the Harz reservoirs and the consumers in the Harz foreland and the north German lowlands into electricity.
From 1969 to 1993 the Harz waterworks were headed by Martin Schmidt , who thus had a significant influence on the decisive growth years. This researched and documented in his last years on the job and at the beginning of his retirement intense in Upper Harz Water shelf, thus laying an important scientific foundation for future UNESCO - World Heritage recognition of this historic hydraulic structures.
- Facts & Figures. HWW website, accessed on March 2, 2020.
- NN : Dr. Finkenwirth , in: Hannoversche Köpfe aus Verwaltung, Wirtschaft, Kunst und Literatur , Vol. 1, Verlag H. Osterwald, Hanover 1929. ( August Heitmüller drew the heads. Wilhelm Metzig designed the entire equipment of the work. The texts have no author names, no page numbers or table of contents are given in the book).
- cf. Heinz Röhl: History of the gas and water supply in Hildesheim 1861-2001. Published in self-publishing , Hildesheim of 2002.