Flood protection in Eggiwil

The small stream of the Schmittegraben in Eggiwil and its tributary, the Holzbach, do not appear particularly dangerous at first glance. However, the hazard map shows a considerable risk for the area. A local company on the riverfront wanted to expand its premises and therefore asked GEOTEST AG to analyse the hazard situation. In 2021, the resulting study confirmed that a hazardous situation indeed occurs in the event of flooding.

Deepening the stream

Simple measures, such as deflection walls on the existing plots, cannot sufficiently alleviate the situation in the Holzmatt area. GEOTEST therefore elaborated several variants in a preliminary project (completed in January 2022) for the Eggiwil flood protection corporation. Deepening the stream channel over a length of 160 metres was found to be particularly suitable. The advantage of this option is that the water would have more space under the many bridges and could drain away more easily.

The Holzbach (2) flows underground into the Schmittegraben (1). This in turn feeds into the Emme (3).

Deepening the streambed will reduce the risk of flooding in the Holzmatt area.

This deepening will be combined with three other measures: the installation of two alluvial wood screens, the new construction of two bridges, and the demolition of three old buildings that were too close to or in some cases on top of the stream.

The three buildings have already been demolished.

Improved passage for fish

The consequences of these measures are not only reduced flood risk, but also ecological enhancement of the watercourses. The opening up of the 40-metre-long covered section of the Schmittegraben will give the water more space. In addition, the demolition of the old concrete weirs will make it easier for fish to pass through at the confluence with the Emme.

Die Mündung des Holzbachs in die Emme ist nun fischgängig.

The confluence of the Schmittegraben with the Emme was redesigned.

Start of construction
In February 2022, the plans for the construction project were solidified in consultation with the landowners and relevant authorities. Canton Bern issued the building permit in December 2023, and construction work began in March 2025 under construction management by GEOTEST.

Most of the work is expected to be completed by autumn 2025. The Holzmatt area in Eggiwil will then be better protected against flooding and the situation will be much safer for the residents