Water Mill since 1436
The Bachmanns Water Mill is the oldest industrial enterprise in Tønder town. It was mentioned for as long back as 1436. The present mill is from 1598. A dam with an upstream impounded millpond blocks the passage for upstream migrating houting. The River Vidå has thus been dammed at Tønder for more than 400 years. Today, the mill is used as a cultural centre.
The mill wheel does no longer exist – but the 2 m high dam is still in function. The dam was latest rebuild in 1975, when a fish ladder was established. Trout and salmon, but not houting, may pass the fish ladder under favourable conditions.
The project
With the purpose of creating passage opportunities in the watercourse, retaining parts of the millpond as nursery area and restoring spawning grounds the following actions under the Houting-project will be undertaken:
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The weir in the eastward bridge gap will be dismantled whereas the westwards weir will be maintained in order to uphold the water level in the reduced millpond.
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A 210 m weir will be constructed longitudinal within the millpond from the present upstream border of the millpond (constituted by another bridge) down the middle of the pond to the Bachmann Mill. This will divide the pond in two. The western side will appear as a reduced millpond functioning as nursery areas.The eastern part will appear as a watercourse within the pond.
It is necessary to retain the current hydrological conditions in the areas west of the millpond where many old buildings could otherwise suffer damages to their foundations due to reduced groundwater levels.
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The eastern side will become a continuum of the river, as a 210 m riffle with a gradient of 4-5 ‰ will be constructed with a 40 cm bottom layer of stones and gravel with 1-3 sections of spawning grounds and resting areas.
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Downstream Bachmanns Mill a 270 m riffle with an average gradient of 4-5 ‰ will be constructed in the present river bed with enforcement of the riverbanks and a bottom of gravel and stones.
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A fauna passage for otter under the bridge will be constructed.
The principle of constructing a fauna passage within a lake, in which it is necessary to retain the existing water level, are gradually becoming more and more well-known. The pictures show a fauna passage in Lake Haderslev . The fauna passages at Bachmann’s Mill and St. Jyndevad will be constructed in a similar way.
– Photos: Hans Ole Hansen, Danish Forest and Nature Agency