The second stage of the land restoration of the brook Stilles Bächlein took place over the past weeks. A small brook got a big makeover.

The Stilles Bächlein, which literally means quiet brook, did indeed flow quietly for many years. Too quietly, so that large deposits in the form of silt, mud and sand formed in the streambed, which had a negative effect on the fish population. “Trout need a gravelly substrate to spawn,” says cantonal fisheries supervisor Beat Rieder. But the gravel is also an important source of life for the many insect larvae such as the creek flea, stonefly, mayfly and others.

The engineer in charge, David Hodel, adds: “That’s why we make sure during the restoration that the water no longer flows so still, but keeps moving through small eddies.” To achieve this, the engineer works with varying water depths, streambed widths and obstacles in the water. Stumps of trees, small rocks, bundles of branches of hardwood, and trunks create movement in the water and provide habitat and shelter for fish, insects, amphibians, and reptiles.

Rieder explains: “The fish, but also the amphibians, feed on the insects and insect larvae. A richly structured watercourse will attract more of these insect larvae, which in turn has a positive effect on the fish population. This creates life in and around the Stille Bächlein.”

Trouts return to spawn
“The brown trout from the River Saane migrates upstream to spawn. If they find a tributary, they go there to mate,” says Rieder. He assumes that the trout will enter the Stille Bächlein from the Saane in late autumn to spawn, and when the young fish are big enough, they will swim back into the Saane.

Members of the Saanenland Angling Club have already observed the first successes in the upper part of the stream, which was supplemented with structural elements and gravel last summer. “These small brooks in meadows and forests are very important for the fish population. Unfortunately, there are very few left in mountain areas,” the fisheries supervisor notes.

Because the Stille Bächlein has little water in summer and the water heats up considerably, which is disadvantageous for the brown trout, water from the Saane is added to the spring and groundwater. According to Rieder, the additional fresh water and the structural elements will bring out the best for aquatic life.

Eco-friendly excavator operator
Reshaping brooks is a demanding undertaking, which also requires experienced excavator operators with a good imagination, Rieder and Hodel emphasise. Thomas Steiner of the Flood Management Cooperative Saanen has already carried out several land restoration projects. In 2012, he was awarded the title of “Eco-friendly excavator operator” for river restorations. “Land restoration is not an everyday job, it is challenging and fun,” says Steiner.

Partners share costs
The overall project costs of approximately CHF 100,000 are financed by the federal government, the canton, the municipality of Saanen and the land restoration fund of the canton of Bern. As this is a replacement measure for the Grubenbächli, the MOB contributed to the project planning and design costs.

BASED ON AVS/BLANCA BURRI