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From Belfort to the Mediterranean, the Rhône-Mediterranean basin will invest 3.2 billion to preserve water

The committee of bowl Rhône-Méditerranée adopted its water management plan for 2022-2027 in mid-March, or Water Development and Management Master Plan (SDAGE).

A roadmap amounting to 3.2 billion euros over six years. This budget comes from fees paid by consumers and it is the Water Agency which is then responsible for setting up this SDAGE.

Also, four colleges make up the committee: economic users, local authorities, non-economic users and State representatives.

“The basin that suffers the most impact and climate change”

The perimeter of this basin follows the Rhône from the territory of Belfort to Nîmes, and covers the Mediterranean from Nice to Perpignan. “It represents 20% of the national territory and fifteen million inhabitants“, says Martial Saddier, president of the basin management committee and also president of the departmental council of Haute-Savoie. It is one of the six major basins of France, following the six largest rivers.

“The absolute priority is to save water”, slice Martial Saddier. Global warming and its consequences, extensively detailed in the latest IPCC report, are factors that absolutely must be included in this SDAGE.

“There is a retreat of the glaciers, a drop in rainfall in the south of the basin and the postponement of the rain in the North… If we want to get out of it, we have to save water”he continues.

Because this basin with particularly wide contours, since it goes from the glaciers to the sea, also undergoes a multitude of water changes. “We are no longer wondering if it will warm up, the observation is clear, in the Alpine valley, we have already recorded an increase of three degrees. […] It is the basin that suffers the most impacts and climate change, especially around the Mediterranean, where we observe a reduction in rainfall of 15%”, advances Martial Saddier.

In the Rhône, for example, the water balance shows a loss of 128mm of water between the last two thirty-year periods (1961-1990 and 1991-2020), according to the ORCAE AuRA (Regional climate, air and energy observatory).

Pressure on the resource

The Orcae also makes the same observation: “Rising temperatures and falling snow cover will lead to drying conditions and therefore increased pressure on water resources in Auvergne-Rhône-Alpes. This deficit should eventually affect all territories, even those whose water resources is now considered abundant.Water quality could also be impacted.

“We must find substitution in either new groundwater or in the Rhône”, according to Martial Saddier. Rhône which itself suffers a loss of flow. Last year, the Rhône-Mediterranean-Corsica Water Agency warned of the situation of the flow of the river, which has already decreased and could drop by another 40% by the end of the century.

“In 2050, the non-Mediterranean tributaries of the Rhône (Saône, Loue, Ognon…) would lose 20 to 50% of water in summer and autumn, and up to 75% in summer for Isère and Durance.“, even adds the Orcae (theClimate Air Energy Observatory of Auvergne-Rhône-Alpes).

In his component of water resource management, the SDAGE thus provides “to save or replace approximately 210 million m3 of water between 2022 and 2027 (i.e. approximately 35 million new m3 per year, which represents the annual consumption of a city the size of Lyon).” An ambition that follows the work already undertaken in the previous SDAGE: “about 32 million m3 per year newly saved or substituted between 2016 and 2021.”

It is also about finding new storage solutions. “We are facing shortages, so when there are excesses, we have to store some of them”, comments Martial Saddier. The SDAGE also aims to go from 88% to 98% in 2027 of good quantitative condition of groundwater. A work of renaturation of the rivers is to be made to allow fish and sediments to circulate. “The deep strategic aquifers must be able to recharge and this requires the preservation of wetlands“, says Martial Saddier.

As well, “in 30 years, the waters of the Rhône have warmed up by 2°C at its mouth in the summer season“. However, the warming of the waters could aggravate the problem of water quality, by promoting the development of bacteria and the colonization of algae and invasive and/or pathogenic species. In parallel, the capacity for self-purification environments could decrease, as well as the dilution capacity of waterways, underlines the ORCAE.

Among the quantified objectives, the SDAGE also aims for 67% of good ecological status of aquatic environments, against only 48% currently.

“The evaluation of the progress made to achieve the objectives of the SDAGE 2016-2021 shows that the ecological state of surface waters is relatively stable, while at the same time the pressures exerted on aquatic environments are increasing significantly (increase in population, evolution of land use, development of economic activities), attesting to the effectiveness of the actions taken to control the impacts of these pressures.

Economic actors in water management

The specificity of this basin, “is the demographic growth and it is also the first industrial basin and the most touristic, between skiing and the Mediterranean”, explains Martial Saddier.

Sectors of activity with which it is necessary to deal. “Water is an essential element for the functioning of industries. By using it as a source of energy, calorific fluid or receptacle for waste, manufacturers participate in the water cycle. For this reason, the industry is, as a user of water and aquatic environments, a stakeholder in the bodies that define the methods of water management and preservation. A guide had thus been made available to them in the previous SDAGE.

As for tourism, particularly in the Alps, the IPCC report already recalled, last February, that for “prevent future conflicts around the increasing use of water resources by the ski industry in the Alps (but also in Scandinavia),[il conseillait] the establishment of large-scale governance to avoid fierce competition around this resource”.

Auvergne Rhône-Alpes is also an agricultural region and the fight against agricultural pollution is largely included in the SDAGE, which thus provides for “guarantee the quality of the resource for 281 priority catchments for the supply of drinking water registered in the SDAGE 2022-2027, of which 80% are degraded by pesticides and 45% by nitrates.” The basin committee notes, however, that in the last SDAGE, it was the agricultural world that made the most efforts, both in terms of quality and quantity.