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Valentine Gaxieu
Published on
Nov 15 2024 at 10:00 a.m
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As part of the Ognon River contract, the Joint Development Union for the Middle and Lower Ognon Valley (SMAMBVO) and the Jura Nord Community of Communes are launching a vast program of restoration of the Vèze d’Ougney.
This project, under negotiation for 12 years and supported by the elected officials of Taxenne and Ougney, as well as by local residents, aims both to resolve ecological disorderswith the restoration of biodiversity and the proper functioning of the stream, and provide answers to flooding issues.
A stream disturbed by old developments
The Vèze d’Ougney stream was disrupted by the different activities which have developed on its banks over time. Indeed, its meanders have been rectifiedits bed has been cleaned and its banks have often been modified or rip-roared. These developments, coupled with significant water quality problems, have modified fish and insect populations living in the river.
” Today, there are more leeches and mosquito larvae as ephemerals (May fly) and other sensitive insects which should develop in its bed. Trout, minnows and sculpins have disappeared for a long time of this small watercourse”, presents the SMAMBVO in a press release.
Risk of flooding downstream
Another problem, historical drainage and the disappearance of hedges on upstream areas, coupled with the acceleration of water during the rectilinear course of the watercourse, amplify the frequency and speed of flow variations in case of rain. This situation increases the risk of flooding downstream.
“In Taxenne and Ougney, urban developments near its bed and reduction of space left in the stream have a similar effect,” explains the SMAMBVO.
Transform 1,095 m of degraded stream
At the start of the year, the union obtained the final authorizations from owners allowing work to begin on the section located in the town of Taxenne. This work will make it possible to transform the 1,095 m of altered stream in 1,400 m of restored waterways.
The organization develops: “The total re-creation of the stream will be carried out. In the inhabited areas of Taxenne, earthworks of the banks will allow the stream to spill over into sectors without issues. This will reduce the power and frequency of floods in the town.” A scupper (the equivalent of a second arch) will be built on the right bank of the bridge.
Increase available water during droughts
Outside of inhabited areas, the size of the low water bed (low water period) will be reduced. “The stream will spill over more easily into these areas. The development of meanders will allow the slowing down of currents and the diversification of habitats for wildlife »explains SMAMBVO.
Slow and regular overflows will therefore facilitate the infiltration of water into the soil, and will increase the amount of water available during periods of drought.
Slow down the speed of floods
The bottom of the stream – which has been dug over the years – will be returned to its natural altitudethus increasing the quantity of water stored naturally in the soil.
This slowing of the waters will also have the effect of slowing down the speed of the floods in Ougney downstream, making them less destructive and giving residents more time to react.
Finally, the tacot dyke, located in Ougney, was leveled in order to limit its barrier effect and to mitigate the frequency and severity of flooding.
Seven kilometers restored
In total, seven kilometers de la Vèze d’Ougney will be restored “in the years to come”. In the restored area, monitoring of different indicators will be supported by the union over the coming years, in order to evaluate the effects of the adjustments made and correct any shortcomings in the project.
The work is estimated at €523,695 excluding tax and financed by the Rhône-Mediterranean-Corsica Water Agency, the Department, the Jura Nord Community of Communes and the SMAMBVO.
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