One example of the expansion of the Water Regale network was the optimisation of several ditch courses (the Dam Ditch, Upper and Lower Rosenhof Chutes), mainly during the 19th century, by the construction of so-called Wasserläufen (also Wasserüberleitungsstollen) or water tunnels.
These enabled the distance travelled by the water to be significantly shortened.
It also guaranteed winter working, because the water running underground did not freeze up.
In addition the maintenance cost of a short section of tunnel was much cheaper than that of a long ditch run.
But a  particularly important advantage was the higher discharge capacity.
The tunnels descended the same height difference over a shorter distance and therefore had a steeper incline.
Initially the underground sections were laboriously hewn out with hammer and chisel.
Later gunpowder was used as an explosive, making the construction of water tunnels considerably easier and faster.

Because most of the energy was needed to drain the mines of water and because the need for that continued to grow as mines became deeper, there were attempts early on, to dewater mines using drainage adits (Wasserlösungsstollen).
This entailed driving tunnels from the mines to the valleys, through which water could drain away under gravity.
The deeper the level of drainage, the longer the adit had to be.
The longest of these tunnels is the Ernst August Adit, built in the mid-19th century, which is 35 kilometres long.
It collected water from the mines in Bockswiese, Lautenthal, Zellerfeld, Clausthal and Wildemann and led it to Gittelde on the edge of the Harz.
One example of the expansion of the Water Regale network was the optimisation of several ditch courses (the Dam Ditch, Upper and Lower Rosenhof Chutes), mainly during the 19th century, by the construction of so-called Wasserläufen (also Wasserüberleitungsstollen) or water tunnels. These enabled the distance travelled by the water to be significantly shortened. It also guaranteed winter working, because the water running underground did not freeze up. In addition the maintenance cost of a short section of tunnel was much cheaper than that of a long ditch run. But a  particularly important advantage was the higher discharge capacity. The tunnels descended the same height difference over a shorter distance and therefore had a steeper incline. Initially the underground sections were laboriously hewn out with hammer and chisel. Later gunpowder was used as an explosive, making the construction of water tunnels considerably easier and faster.
Because most of the energy was needed to drain the mines of water and because the need for that continued to grow as mines became deeper, there were attempts early on, to dewater mines using drainage adits (Wasserlösungsstollen). This entailed driving tunnels from the mines to the valleys, through which water could drain away under gravity. The deeper the level of drainage, the longer the adit had to be. The longest of these tunnels is the Ernst August Adit, built in the mid-19th century, which is 35 kilometres long. It collected water from the mines in Bockswiese, Lautenthal, Zellerfeld, Clausthal and Wildemann and led it to Gittelde on the edge of the Harz.
Upper Harz Water Regale