]> 2026-04-04T19:42:42+00:00 Case study:Marsh restoration on the Merlue 500 en 28 3 rex r8-merlue vbat.pdf Case study description by ONEMA (French National Agency for Water and Aquatic Environments) (in French) Approved 0.5 - 2 m 3 2 - 5 m Yes No Yes No Awaiting results No Fish,Yes,Yes,No,Yes,No,Awaiting results Invertebrates,Yes,No,No,No,No, Fish Invertebrates Yes No Channel widening Association pour le développement et l’animation de la Petite Montagne Western Highlands EU LIFE Programme No No Yes true No No No No ,No,No,No,No,No, No 1.PICT0362.JPG 2.IMG 5871.JPG 3.DSCN0049bis.JPG 5.DSCF0027.JPG 4.IMG 3735-bis.JPG The Merlue just downstream the marsh in summer 2009. The bed moved [on the left] on the edge of the marsh [on the right] has been filled during the restoration works. Uprooting and burning of willows present in the marsh during the summer of 2008. The new riverbed slightly excavated. The Merlue in the restored area during the winter 2008-2009. In the foreground, we can see a stone structure put in place in order to raise and narrow the riverbed. First flood in autumn 2008 in the marsh, after its restoration. 24.5 Parc naturel régional du Morvan, Office national de l’eau et des milieux aquatiques (Onema), université de Franche Comté. Parc naturel régional du Morvan, Office national de l’eau et des milieux aquatiques (Onema), université de Franche Comté. 46.50444,5.635359 Eric Association pour le développement et l’animation de la Petite Montagne Chaput 1 ,Restoration of riparian marshes,Channel widening, ,,, The project allowed to increase by 300 m the stream length and to raise the water level along 1 500 m. Ten hectares of wetlands have been restored, which are also a relevant flood storage area. Habitats diversity and functionality were increased and initial monitoring results are encouraging, however it is too early to assess the biological gains of the operation. 936 4.IMG 3735-bis.JPG 2008-07-01Z 2454648.5 Complete The Merlue is a 7,9 km long tributary of the Valouse, with a small watershed (less than 15 km2) half covered by managed forests, half by non (or little) fertilized grassland. The fish population is mainly composed of two species : brown trout and bullhead (Cottus gobio). The invasive signal crayfish (Pacifastacus leniusculus) is also present. In its middle stretch, the Merlue used to cross a marsh, however more than one century ago, the riverbed was moved to the edge of the marsh in order to drain the land and plant softwood (which has never been productive). The new configuration affected the summer connection with the groundwater table. This explains both the frequency of drying up and the overheating of a portion of the river, two phenomena that are not observed downstream from the marsh, where the Merlue is in its original bed. In the lower stretch, the riverbed was enlarged by approximately five meters, resulting in shallow waters and reduced available habitat for aquatic wildlife. The Merlue is part of the Natura 2000 site “Petite montagne du Jura”. Restoration actions were carried out within the LIFE project “Ruisseaux de têtes de bassins et faune patrimoniale associée” (LIFE 04NAT/FR/000082), focusing on restoring the population of native white-clawed crayfish (Austropotamobius pallipes. Before the works , 19,4 hectares were acquired in the marsh, thanks to the intervention of the “property development and rural settlement society” ( SAFER) . Four hectares of invasive willows and undesirable tree species were removed. The old riverbed was found by infrared photography , since the analysis of land registers did not allow to locate it. The stream was moved where the former bed was and the rectified channel was filled. The new riverbed was only slightly excavated and was intentionally undersized (30 x 30 cm), so that it would naturally recreate its shape. Some ramps were was positioned under the bed where specific anthropogenic constraints (bridge, crossing for agricultural machinery , etc. ) did not allow a free dynamics. In the downstream portion, softwoods were removed . The riverbed of the Merlue was narrowed and raised by 50 cm adding sediments excavated in the nearby village (for the foundation of a house), and arranged in order to recreate a sinuous low-flow channel and a sequence of riffles and pools. The stretch ends with a drowned rock ramp, positioned at the same height as the current bottom of the riverbed . Marsh restoration on the Merlue marsh restoration on the merlue 1450 Rhône-Mediterranean Rhône - Méditerranée Restoration of riparian marshes Merlue merlue Merlue merlue 12 Merlue 26,000 € for land expropriation Habitat and biodiversity 136 100 - 500 k€ FRDR493a 52 2008-09-01Z 2454710.5 2008-07-01Z 2454648.5 2012-07-31T17:35:00Z 2456140.2326389 2019-01-02T15:12:29Z 2458486.133669 Marsh restoration on the Merlue 500 1 plainlist 5 [[Category:Case study]] [[Project title::!Marsh restoration on the Merlue]] [[Subcatchment title::Merlue]] Marsh restoration on the Merlue# QUERY3acb7c9adb4dcccde974c6d455ac1d86