Rems and Winterbach · River, water, nature and history

Weirs on the Rems and fish passage

Between its mouth in the Neckar and Plüderhausen, the state lists eleven weirs and transverse structures in the Rems where something is to be done for the fish. Most belong to old mills where small hydropower plants run today. For fish such as barbel and common nase, which migrate over long distances, they are obstacles. The EU Water Framework Directive requires that fish and small organisms can once again move along the entire length of the river. This is also the most important ecological condition for a Remswelle.

Why fish passage matters so much

Fish migrate: upstream to spawn, downstream as young fish, into deeper stretches in winter. For barbel and nase, according to the state fishing association (Landesfischereiverband), migration distances of more than 100 kilometres are known; both depend on clean gravel for spawning. The LUBW describes passability as being of "outstanding importance" for species-rich communities typical of the watercourse – and transverse structures as a permanent obstacle, not only for fish but also for small organisms on the river bed. Under the Water Framework Directive the fish in the Rems are currently rated only "moderate", and the state sees a high need to make the Rems passable again over about 42 kilometres. → Wildlife and plants on the Rems

The weirs from the mouth to Plüderhausen

The supporting documentation of the Stuttgart Regional Council (Regierungspräsidium) for the 2022–2027 management plan lists these transverse structures with planned measures for the Rems below the Walkersbach (Rems kilometre counted from the mouth):

The planned measures are mainly improvements for downstream fish migration, at some weirs also for upstream migration and for more minimum flow. The list contains no transverse structure in Winterbach. The "weir" usually talked about in Winterbach is the outlet structure of the flood retention basin under the Ostlandstraße bridge; at normal water levels the Rems flows level through it. A little further upstream, just before the Remsknie (bend of the Rems) by the bird tower (Vogelturm), there is a small fixed sill that is not included in the list. According to our map comparison, the mill race branched off the Rems at roughly this spot in 1832 – the sill probably stands at an old weir site. → Time travel: the historic course of the Rems

What has already been built

Several weirs now have fish passes. In Waiblingen a fish pass was built at the Hahn'sche Mühle around 2001; in 2011 bed ramps with a low-water channel followed at the Hegnacher Mühle and the Vogelmühle, together with a riverside park, for more than two million euros. In Remseck a fish pass at the Schiedtmühle weir was inaugurated in 2019, costing 720,000 euros; species expected there include barbel, chub, roach and gudgeon. During the 2018 restoration between Winterbach and Remshalden, the side streams were reconnected to the Rems via rough ramps. At the weir near Remshalden-Grunbach there is a fish ladder whose passability the Bürgerwerkstatt Remshalden (citizens' workshop) wanted to have checked in 2023.

Hydropower and minimum flow

Where a mill race diverts water from the Rems, less remains in the actual river bed. The LUBW therefore requires sufficient minimum flows for such diversion reaches, so that the river keeps its natural functions. For the Rems from its mouth to Schorndorf this is explicitly an issue in the programme of measures, among other places at the Geheime Mühle and at the Hahn'sche Mühle in Schorndorf. How sensitive this is can be seen at the Birkelwehr in Weinstadt: after maintenance work in 2020, and again in dry summers, the Rems below it dropped sharply; in 2020 residents and river wardens reported dead fish, mussels and small animals.

What this means for the Remswelle

A wave needs head – and head is usually created by a structure in the river. From the fish's point of view, that is exactly the problem. That is why, for us, fish passage is a condition, not a bargaining chip. Modern waves solve this in two ways: the installation can be lowered when it is not needed, as in Pforzheim, or the wave lies in a side channel while the river remains passable with a fish pass, as in Nuremberg. With the idea of closing part of the stepping stones, at least one gap must always remain open and passable for fish. Which solution works at the "Remswehr" will be clarified by the feasibility assessment together with the fisheries authority. → Ecology and permits · → The Winterbach site

Frequently asked questions

How many weirs does the Rems have?

Between the mouth and Plüderhausen the state lists eleven transverse structures needing measures, plus further ones upstream near Schwäbisch Gmünd. Smaller sills that need no measures are not included.

Is there a weir in Winterbach?

The "Remswehr" is the outlet structure of the flood retention basin under the Ostlandstraße bridge; at normal water levels it has no step. Upstream, just before the Remsknie, there is a small fixed sill. The list of transverse structures needing measures contains none in Winterbach.

Which fish migrate in the Rems?

Barbel and nase in particular cover long distances – more than 100 kilometres, according to the state fishing association. But chub, roach and gudgeon also benefit from passable weirs.

Does a surf wave obstruct the fish?

It must not. A wave must be built so that fish can continue to move through the river – for example with an installation that can be lowered or with an open gap. This is a precondition for any permit.

Sources: Regierungspräsidium Stuttgart / Umweltministerium Baden-Württemberg (Ministry of the Environment), WRRL-Begleitdokumentation Teilbearbeitungsgebiet 42 "Neckar unterhalb Fils bis oberhalb Enz" (Water Framework Directive supporting documentation, sub-basin 42), as of December 2021 · LUBW, "Durchgängigkeit für Tiere in Fließgewässern – Leitfaden Teil 1: Grundlagen" (2006); "Mindestabflüsse in Ausleitungsstrecken" (2006) · Haberbosch, Hoffmann, Wnuck, "Vom Wildfluss zur Wasserstraße – Fischfauna und Fischerei im Mittleren Neckar", Landesfischereiverband Baden-Württemberg, August 2012 · Stadt Waiblingen (town of Waiblingen), official gazette 2011 (Hegnacher Mühle, Vogelmühle) · Freie Wähler Remseck, "Großinvestition in die Gewässerökologie", 14.09.2019 · Bürgerwerkstatt Remshalden, group on nature, environment, sustainability & climate, 14.04.2023 · Zeitungsverlag Waiblingen, 31.08.2020 and 19.09.2022 (Birkelwehr) · Regierungspräsidium Stuttgart, "Die Rems fließt wieder", 19.12.2018 · Wikipedia, "Rems" (hydropower plants; accessed 26.09.2026) · Remswelle initiative, local knowledge (Remsknie)

Last updated: 15 October 2026 · Initiative Remswelle