The catchment area of the River Sneum Å system is 510 km², making it the 14th largest river in Denmark .
The main watercourse River Sneum Å (26 km ) and the tributary River Holsted Å (37 km ) run towards southwest and west respectively, before they converges approx. 10 km before the outfall of in the Wadden Sea at Sneum Sluice.
The mean water flow of River Sneum Å and River Holsted Å before their convergence is 3,200 l/s and 3,000 l/s, respectively. The mean water flow at the outfall in the Wadden sea is 7,000 l/s (min. 1,900 l/s, max. 38,000 l/s).
The upper half of River Sneum Å along with the major part of tributaries is relatively unmodified with good physical conditions, while it is channelled on the lower half, where it runs through moor plains and marshland.
Apart from the upper few kilometres River Holsted Å holds unmodified in-stream habitats with good physical conditions.
All other parts of the river system are heavily modified. Drifting sand, former modifications, dredging, harsh handed in-stream maintenance and cutting of weed have a high, negative effect on the physical conditions of the watercourse.
About 70 % of the catchment area is used by agriculture. Land use is however considered varied, comprising of intensive arable agriculture and forest/plantation activities on the moor plains and moraine islands and extensive grazing and hay harvest in the stream basins.
A systematic mapping of the possible spawning areas in the system has shown that there are only shorter stretches with suitable spawning grounds for salmonids in the main run of River Sneum Å.
In River Holsted Å there are longer stretches with excellent spawning possibilities, which in turn, however, are not accessible because of weirs at several fish farms. Several other smaller tributaries hold good spawning areas as well.
Ecological status is good on approx. 65% of the water stretches in the system. Local problems in the major rivers Sneum Å, Holsted Å and Terpling Å are caused by fish farming.
Habitat area
The River Sneum Å is included in the 514 ha habitat area no. 79 ‘River Sneum Å and Holsted stream valley (see map).
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River Sneum Å with tributaries.
p : River stretch open to houting from project
start
p : River stretch open to houting after Houting-
project
p : River stretch closed but suited for houting –
the stretch are not included in the Houting-
project
p : River stretch of no interest to houting |
The Houting-project in River Sneum Å
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(1)&(2): The river will be remeanderen for a stretch of approx. 2-4 km improving the river and creating nursery areas for the houting fry.
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(3): The Bramming Fish Farm will be bought and dismantled.
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(4): The Endrup Mill Fish Farm will be bought and dismantled.
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(5): The Hjortkær Fish Farm will be bought and dismantled.