Kiliansteich

The Kiliansteich (literally "St. Kilian's Pond") is one of the oldest reservoirs in Germany. The reservoir is located near Straßberg (Harz) in the German state of Saxony-Anhalt and supplies drinking water. It impounds the Büschengraben stream. The lake is part of the heritage area ("Flächendenkmal") of the Lower Harz Pond and Ditch System.
The reservoir has a rockfill dam with a watertight clay core that sits on a shale bedrock.
History.
Originally there were four small ponds in a row on the site of the present-day reservoir that had been built for the mining industry. Two of those were broken in 1901 and 1944 and all were in a poor condition. As a result, from 1989-1994 a new, higher dam was built at the site of the lowest dam; the two middle ponds were removed and the upper one, the Upper Kilian Pond ("Oberer Kiliansteich"), built in 1703, was upgraded into a pre-dam ("Vorsperre").
Originally laid as a drinking water reservoir, the lake is used today for flood and drought protection.
The dam on the original "Lower Kilian Pond" ("Unterer Kiliansteich") was about 10 m high and had a retaining capacity of 165,000 m³. During the course of renovation the old wooden bottom outlet was salvaged on 25 September 1990 as the result on an initiative by Erika and Siegfried Lorenz. Following long-term conservation work at the "Harzwasserwerken" in Clausthal-Zellerfeld, who paid for the cost of transports and conservation, it was returned on 19 August 2010 to Straßberg. The wooden raceway is now a museum piece in the Glasebach Pit.
Sources.
Talsperren in Sachsen-Anhalt, Autorenkollegium, Hrsg. Talsperrenmeisterei des Landes Sachsen-Anhalt 1994