Based in Préaux, south of Seine-et-Marne, Bertrand Collumeau is one of those farmers whose activity weighs heavily on the quality of the water flowing from the taps of Parisians.
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The family farm of 400 hectares of field crops that he took over in 2003 with his brother is located in the Lunain valley, near the sources of Villemer, a catchment area essential to supply the capital, to a hundred kilometers as the crow flies away.
A worrying concentration of pesticides and nitrates
“Paris’ drinking water supply scheme is based half on water taken from the Seine and Marne, for the other half on groundwater collected in neighboring rural regions”, explains Dan Lert, chairman of the Eau de Paris public authority and deputy mayor in charge of ecological transition.
However, the quality of this groundwater is strongly compromised by human activities, in particular agricultural activity, the intensive practices of which lead to a worrying concentration of pesticides and nitrates which requires heavy and costly treatments.
Also, to better protect this resource from pollution, Bertrand Collumeau decided, last year, to carry out the ” big jump “ and converting its farm to organic farming by committing to the pioneering system set up by Eau de Paris. A device that has just received decisive support from the Seine Normandy water agency (AESN) via the signing, Tuesday, May 25, of a territory contract which commits the two partners for six years.
Prevention is better than cure
At the heart of this contract, we find an original aid system, endowed with 47 million euros, 80% funded by AESN, the remaining 20% being paid by the Parisians water tax. “Based on the principle that prevention is better than cure, this envelope is intended to provide financial support to operators who undertake to adopt more sustainable or organic cultivation methods with beneficial effects on water quality”, explains Manon Zakeossian, head of the resource protection department at Eau de Paris.
The amount of aid varies between 150 € and 450 € per hectare, depending on the type of farm and the measures adopted by the voluntary farmer, a bonus going to those who commit to a conversion to organic farming.
This financial incentive was decisive in convincing Bertrand Collumeau to take the plunge. “We could not get into organic farming solely out of conviction: the project had to be economically viable. In this respect, aid per hectare is obviously not insignificant ”, he admits.
Diffuse “diffuse pollution” difficult to apprehend
Like him, around fifty farmers were involved in the program at the start of 2021, representing 8,200 hectares. Ultimately, Eau de Paris and AESN hope that between 100 and 200 additional farms could be affected in the four priority catchment supply areas which cover 240,000 hectares.
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“This is the first time in France that an operator has set up a system of payments for environmental services designed with and for farmers in order to protect water resources in the long term. We can hope that, as the success increases, this model will gain ground at the national level ”, Dan Lert wants to believe.
As for judging the effectiveness of the water quality program, it will probably be necessary to wait a few years as this phenomenon of « pollution diffuse » is difficult to understand, the transfer of pesticides and nitrates from the soil to the water table can take a few days to several months, or even several years. Therefore, the measurements taken on the nitrate concentration show that we are well beyond the standard of 50 mg / L, the quality limit for drinking water.