A sidestream for Trout

The Trout’s Upstream Journey

Each autumn, trout swim up from Lake Vättern to spawn in the Hjo River.
The farther upstream the trout can reach, the greater the available spawning grounds – and the more trout will return to Vättern.
A key part of local fisheries conservation is removing or bypassing obstacles that block the trout’s migration.
While trout are incredibly capable of navigating natural rapids and falls, they often struggle to pass man-made barriers – like the old dam here at Grebbans Mill.

A Bypass Stream to Aid Migration

The barrier at Grebbans is a mill dam with a drop of 6.5 metres.
Several solutions were tested to help the trout ascend on their own. Eventually, a bypass stream (sidoström) proved to be the best option.
In simple terms, this is a constructed stream that curves around the obstacle. This allows the dam to remain intact while giving trout an alternative path.

In addition to aiding migration, the bypass stream also functions as a spawning and nursery area.

A Well-Integrated Nature Solution

The bypass stream was completed in 2001 and required around 500 tonnes of rock and boulders. It has drawn attention for its steep gradient and for how well it blends into the surrounding landscape at Grebbans Mill.

Every autumn, approximately 300 spawning trout now make their way up the bypass stream.

Facts

• Length: 183 metres

• Average gradient: 5%

• Steepest section: 12%

• Total elevation gain: 9 metres

Follow the Nature Trail

The nature reserve is a green oasis in the heart of the town, offering wonderful outdoor experiences all year round. Follow the Nature Trail along the Hjo River, from Hjo Harbour all the way up to the small lake Mullsjön, just west of the town.
This lush and leafy path takes you on a historic walk through wild landscapes, rich in birdlife – right in the middle of Hjo.

You can easily find the trail by following the wooden signs marked “NATURSTIGEN” along the river.
The full walk is approximately 4 km, from Hjo Harbour to Stämmorna at Lake Mullsjön.

Trail Information

• Waymarking: Clearly marked nature trail with wooden signs: "NATURSTIG"

• Length: Approx. 4 kilometres

• Food along the trail: YES – restaurant Stampens Kvarn

• Toilets: Dry toilet at Stämmorna, Mullsjön

• Open: Year-round

• Managed by: Hjo Municipality

• Protected area: Part of the EU’s ecological network of protected areas, Natura 2000