50 years GSI



The new accelerator facility FAIR is under construction at GSI. Learn more.


GSI is member of


Funded by




Environmental compensation

The FAIR construction project is being accompanied by environmental compensation measures. An urban development agreement for regulating the compensatory measures was drawn up for this purpose. Environmental supervision is accompanying the planning and construction processes, and “round table” meetings with professional authorities and experts are held regularly. The local groundwater, vegetation, and forests are being monitored during the construction process. The environmental compensation measures for FAIR are being implemented in the facility’s immediate surroundings and take into account the forest, local wild animals such as amphibians, reptiles, and bats, and rare plants and habitats.

Reforestation measures in the immediate surroundings

The reforestation measures were carried out in the immediate area of the new facility. For example, new trees were planted in the districts of Arheilgen (Täubcheshöhle and Kalkofen) and Wixhausen (near the B3 highway and Hahnwiesenbach) as well as in the near of Ober-Ramstadt and Riedstadt.

In addition to the reforestation, existing stretches of forest were upgraded through so called forest restructuring measures. FAIR also concluded a non-utilization agreement regarding certain parts of the Mörsbacher Grund nature reserve and the Kalkofen forest. The resulting absence of forestry activities in these areas is creating a retreat area for plants and animals and promoting the natural diversity of this habitat.

Protective measures for bats, amphibians, and reptiles

Various environmental compensation measures have been taken to protect the local animal species. For example, alternative habitats have been created for bats. Amphibians have been relocated and their migration paths have been rerouted. New habitats for sand lizards have been created.

A natural monument and a nature reserve for threatened and rare plant species

As part of the plan to preserve threatened and rare plants, the Stahlberge natural monument in Darmstadt-Arheilgen has been restored. This area is now a suitable habitat for a number of animal species that are on the Red List. The new biotope provides a permanent habitat for rare grasses and flowering plants.

In the meadowlands of the Mörsbacher Grund nature reserve, which are located west of Messel, environmental measures were taken to promote the high level of species diversity. The species include a variety of grasses and herbaceous plants as well as rare species such as the Siberian Iris and various types of orchids.

In this stretch of forest along the Mörsbacher Grund nature reserve, wild plants and animals can develop undisturbed thanks to FAIR.
Two plants on the IUCN Red List of threatened species, wormwood broomrape (left) and Berg-Haarstrang (Peucedanum oreoselinum), grow within the Stahlberge natural monument.
Photo: M. Bernards/FAIR
Photos: M. Bernards/FAIR (l.), PGNU/FAIR (r.)

Accompanying projects

Special measures are being taken in order to minimize the impact of the construction process on local residents.


In order to reduce the traffic on public roads, the concrete needed for construction of the buildings is produced in a compounding plant on the construction site. In addition, the excavated soil is brought directly to storage areas next to the construction site rather than transported elsewhere via the public road network.

Before the construction work began, a construction road was built that directly connects the B3 highway with Messeler-Park-Straße in order to leave the traffic around the industrial area east in Wixhausen and the residential districts undisturbed.

The roads around the GSI and FAIR complex are kept clean by means of a tire washing facility that has been installed on the FAIR campus. If necessary, the construction trucks drive through the washing facility before they enter public roads.


The tunnel for the SIS100 accelerator ring is being built by means of the cut-and-cover construction method. As part of this process, the groundwater is being locally drawn down. The water that has been pumped away is channeled back into the groundwater at approximately 50 discharge or infiltration wells in the direct vicinity of the construction site. The groundwater level is continuously monitored at measuring stations located all around the construction site. After the construction measures have been concluded, the groundwater will once again be able to flow normally.

The surveyor’s network

Survey pillars have been set up at various locations around the FAIR construction site (see photo). They are the key points of a virtual network of measuring lines that crisscross the construction site. With the help of this surveyor’s network, surveying engineers superimpose the construction plans on the construction site and can determine exactly where each building should stand and where each road should run. The survey pillars are protected by concrete rings.

Survey pillars at the Mörsbacher Grund nature reserve
Photo: M. Bernards/FAIR