During the preliminary study it was discovered that peat beds in the Ore Mountains were damaged either by the removal of peat or dense networks of ditch systems. Drainage ditches still active today were continuing to destroy the moors. Various techniques were used to prevent the concentrated and rapid drainage of water through the ditches. The most frequently used methods were the construction of dams and filling of ditches with various natural materials. Until about 2010, measures were performed manually for the most part. This was due, among other things, to the inaccessibility of locations where measures were carried out and the sensitivity of the biotope. The gathering of further theoretical and practical knowledge has made it possible to use the small and/or specialized moor technology utilized today.
Since the majority of the Ore Mountain moors are mountainous raised moors, it isn’t possible to fully block all water flow; water will always drain out of the moors naturally. During the first revitalization phase of the project, the focus was therefore on stemming the concentrated, rapid drainage of water from the moor and restablishing the natural catchment area. It will take a very long time to increase water levels in the moors.
Filling entire ditches or ditch sections is the most effective way to re-water the moors. Depending on the slope, it is possible to increase water levels relatively quickly.
Before this procedure can be executed, material must be gleaned from the vicinity around the ditch.
One special way of filling ditches is “ground raising”. Drainage ditches often extend so far under the ground that it wouldn’t be possible to fill them completely. In such ditches, the aim is to gradually raise the water level.
In most of the moors, there was no excavated material to use in the ditch, making it necessary to build dams in the ditches. Besides considering whether the ditch is dug manually or using a machine, the dimensions of the individual ditches were also central when choosing a construction method.
Simple Peat Fill
The ditch is cut off with a “peat seal”. Necessary material was taken from the area above the dam, so excess water would be able to penetrate the peat beds. Manual execution is possible in small ditches. An excavator must be used for deeper and wider ditches.
Dams with Wood
Especially well-sealed and/or very stable dams are often required in the mountainous raised moors.
Depending on the depth and width of the ditch, it may be possible to use notched and spring-loaded boards, sheet pilings, simple beams with geotextile, or entire tree trunks. Regardless of the wood used, peat and turf containing vegetation are filled in around all constructions.
Sheet Piling Dams
Sheet piling dams consist of notched and spring-loaded boards that are sunk into the ditch. One main prerequisite for using this method is that there must be a sufficient layer of peat.
Sheet Piling Wall and Plank Dams
For this damming method, wood is installed crosswise. It is important for the first plank to be firmly rooted in the water-resistant clay stratum. While geotextile is affixed to the water side of plank dams, this is not done for sheet piling walls. The notches and springs allow the beams to warp, thus automatically sealing the dam.
Trunk-reinforced peat dams
If there is not enough peat to build a large trench and / or the pressure on the dam can be particularly high, stabilization in the form of logs must be built into the dam. The dam is sealed by covering it with sufficient peat.
Digging Re-Watering Ditches
Some moor regions possess a large hydrological catchment area that no longer flows into the peat beds due to barriers (e.g. diversion, pathway, and roadside ditches). To the extent possible, new ditches will be dug in order to direct the water back to the moor.
In the moor region at Salzflüsschen bei Holzhau, such re-watering ditches have been dug that lead directly to the moor peat beds.