Meander projects

Austria did not re-meander the lower Traisen so much as build it a new one: 9.4 km of meandering channel dug alongside the straightened bed, then allowed to rework itself in floods. The adjacent ground was lowered to make about 30 ha of river habitat and 60 ha of floodplain, mostly silver-willow forest.

One kilometre of the Geer at Grand-Axhe was reshaped to restore a sinuous planform and a more varied river corridor. SAR Consult designed and supervised the works, while the river contract managed engagement, maintenance and monitoring.

Povodí Moravy reshaping a straightened lowland channel back towards a natural planform, with the stated aims of slowing runoff, restoring floodplain retention and improving morphology. Small by every measure on this map, and typical of what Czech restoration actually looks like.

New meanders cut along 2.277 km between Bořetice and Velké Pavlovice, replacing 1.891 km of straight channel and adding 386 metres of river. The works also created five pools and a 150 m-wide biocentre.

Denmark straightened the Skjern between 1962 and 1968 to turn its delta into arable land, and spent the following decades regretting it. The restoration cut 26 km of new meanders where 19 km of straight channel had been, dropped the dikes, and let roughly 2,200 ha go back to marsh and wet meadow. It remains the largest single river restoration in Northern Europe.

Finland's early pilot for restoring a forest brook reinstated 3.6 km of the Myllypuro's historical sinuous course and built a flood terrace beside it. A surviving natural reach of the same brook was used as the design reference.

The Veyre's 1.117 km straight agricultural channel was recut through surviving traces of its former bends, producing 1.641 km of river and more than a kilometre of renewed bank. The design added 524 m of channel, pools and riparian planting while retaining farm access.

A new 350 m meandering bed was excavated through the sediments of a former millpond, given a coarse alluvial layer and connected upstream and downstream before the straight channel was filled. The project doubled the 150 m originally proposed after local engagement.

For a century the Emscher carried the Ruhr's raw sewage in open concrete channels, because mining subsidence kept collapsing buried sewers. The fix had to happen in order: 423 km of underground sewer first, and only then could the concrete come out and the channels be widened back into streams. At €5.5 bn it is the most expensive river project in Europe.

Eight kilometres of the Isar through Munich: embankments removed, the bed widened, gravel bars left to form and rock ramps built so fish can get upstream. It had to deliver flood protection and a city beach on the same reach, at the same time.

A 2.2 km pilot reach, rebuilt in 1996 and 1997 as part of North Rhine-Westphalia's Lippe programme. The channel was widened from 18 m to 45 m, bank fixation pulled out, islands built, whole trees put in as deadwood, and the floodplain drainage let back in — expanding open water from 7 ha to nearly 11 ha.

The lower Slampe's 2.1 km drainage canal was replaced by a 4.6 km meandering stream and raised roughly a metre so spring water could again spill onto 105 ha of Dunduri meadow. It was the first large river-renaturalisation project delivered in the Baltic states.

A natural meandering bed was excavated for 1.8 km within a 2.3 km reach upstream of Skuķu lake, replacing the deep straight drain cut through the Dviete floodplain in the 1930s. The river works were paired with grassland clearance and year-round grazing.

The Alzette was moved out of its straight agricultural bed and back into the valley thalweg for 1.4 km, with its bed raised and widened and a secondary arm reactivated. A further 600 m of the Kiemelbaach tributary was restored under the same floodplain project but is not counted in the headline reach.

Canalisation from 1848 onwards cut the Regge from about 70 km down to 50. The Reggevisie programme is putting the curves back reach by reach — roughly 50 km of channel to be returned to a natural planform, with old meanders reconnected and room made for peak flows.

The Kleine Beerze was narrowed and given bends along 6.7 km between Middelbeers and Vessem, reconnecting dry historical meanders and cutting new ones. Parts of the old straight channel remain as a high-water bypass, while 51 ha was set aside for natural water storage.

Oslo brought 1.5 km of Hovinbekken back to the surface between Hasle and Ensjø after more than fifty years in pipes, giving the brook an open, sinuous route through new parks and streets. The urban corridor and water-treatment landscapes cover about 65,000 m².

Radom reconstructed 315 m of the Mleczna as a meandering urban channel, including 171 m of new bends and 144 m of retained natural bed. Four backwater bays, ten riffle-pool sequences, gravel structures and a floodplain channel were added to slow storm water.

The Stržen was redirected from its drainage channel into a 2.1 km former meander on intermittent Lake Cerknica, adding 1.5 km to the watercourse. The old straight bed was filled and the restored hydrology was paired with a large quiet zone for nesting bittern.

Phase 1 reopened the outlet of the Arga's abandoned Soto Sardilla meander across a roughly 2 km reach near the Aragón confluence. Accumulated polluted sediment and confluence riprap were removed, floodplain space recovered and wetlands, islands and riparian planting added.

Northern Sweden's rivers were not straightened for farmland but for floating logs: over 1,600 km of channel was blasted and walled between 1850 and 1976 to move timber. This project restored 66 km across 26 tributaries of the Vindel, reopening side channels the floatways had sealed.

The Aire's concrete canal was kept — as a linear park — and a new bed cut alongside it as a lattice of diamonds, which the river was then left to erode into a course of its own choosing. Roughly 5 km and 50 ha, built in phases since 2002.

Britain's first river restoration project of its kind: about 2 km of the Skerne through Darlington, with four new meanders cut, the bed reshaped and narrowed, banks replanted and footpaths built. It was designed as much to bring the countryside into a town as to fix a river.

The RSPB, United Utilities, Natural England and the Environment Agency replaced 750 m of straightened channel with 890 m of new sinuous bed, reconnecting the beck to its floodplain. The straightening it undid predates 1859.

A Tweed tributary used as Britain's natural-flood-management test bed: 3.5 km of meanders restored, embankments removed, ponds and log dams built and trees planted across the catchment, with monitoring designed in from the start.