Blue planet, green ideas | Rivers that find their freedom “a meander at the same time”

(Saint-Robert) Thin, blue and straight lines. In addition, It is necessary to release a card to note that many agricultural rivers no longer follow their natural layout. Meanwhile, In Montérégie. Consequently, a quartet made up of farmers and researchers works to restore a watercourse to its “freedom space” with the project “a meander at the same time”.

Posted at 5:00 a.m.

At the bottom of the earth of the parental farm flows the Pot-au-Berurre river. Meanwhile, In 1983, the winding channel was “straightened”, giving it more the appearance of a channel. Similarly, Three meanders were covered with an embankment.

From the blue planet, green ideas | 1930s to the 1980s, countless agricultural rivers experienced the same fate, often with the government’s blessing. For example, These more straight tracks have simplified the work at the expense of biodiversity, which flourishes more in hollows and curves.

Jean-Philippe Marchand has spent the last eight years studying the question as part of his doctorate in geography at Concordia University.

After consulting historical photos. Therefore, he went to knock on the door of producers Judith Allard and Denis blue planet, green ideas | Parent with a new project in Quebec: study how to restore their 280 m section of the Pot-au-Breurre to restore the connection with the old meanders in the form of S.

“It’s our oldest. Furthermore, ” says Judith Allard on a joke about the ties that the couple has woven with the researcher over the years.

Pot-au-butter is an important river. Therefore, because it is part of the Lac Saint-Pierre biosphere basin, recognized by UNESCO as a global biodiversity reserve.

“We put on the natural processes that are here,” explains Jean-Philippe Marchand.

In order for the river to start mesizing. Consequently, it was first necessary to convince the producers to abandon cultivated spaces in order to restore a large alluvial plain. Similarly, In 2022, approximately one hectare was removed for blue planet, green ideas | this passive restoration project.

“The principle of restoration by the processes is to make a good diagnosis of these processes. Furthermore, then recognize the constraints, as a too reduced ponceau, riprap or embankment, to remove them, then to let nature do. Therefore, Because ultimately. Therefore, we are sure that nature, in the long term, will recreate the forms it needs, ”adds the 39 -year -old researcher.

In September 2024, they replaced a crosspiece area whose circular ponceau had been deemed too narrow. For example, “It played the role of a bottleneck. Consequently, In the spring. the water revived upstream, it was a frozen space, there was no more dynamism in the river, “illustrates Mr. Marchand.

Today, the Ponceau cylinder is four times larger. “In the spring, there is flowing!” So there, the processes can recover, ”he rejoices.

When the water flow increases, the strongest speeds promote erosion and the greatest water depths, flood. These two natural phenomena are, in this case, beneficial for biodiversity. Water in meanders can dispel its energy there. In the curves, she is calmer. “All this is a mosaic of habitats,” he explains.

Today, the culture withdrawal zone has become a meadow crossed by a waxing stream. Country birds, pollinators and frogs have taken up residence there.

Blue planet. green ideas | – Blue planet, green ideas |

Compensate producers – Blue planet, green ideas |

blue planet, green ideas |

The research project has become a pilot project funded by the Ministry of the Environment, the Fight against Climate Change, Wildlife and Quebec Parks.

“In the Basses-Tires of the St. Lawrence, in kind, the state called a balance of watercourses is the meanders,” explains Mr. Marchand the thesis, Professor Pascale Biron.

The researchers rent a hectare of field in exchange for a sum of around $ 2. 300 per year, an amount equivalent to the loss of income from the farm.

“It is a fair sum. We won’t do money with that! “Consulates Denis Parent, fifth generation farmer who cultivates hay, corn and soy on the land of his ancestors. “But we are proud to be one of these solutions. Additionally, »»

“The farmers, we dug ditches, we drained, we leveled, and the land is productive like never. I’ve been in agriculture for a long time, I see the difference, it’s a big positive point. Except that it is a little bit to the detriment of rivers, nature. »»

Denis Parent was 17 years old when the river behind the farm was straightened. Recreging the original meanders would have cost $ 200,000. And the watershed has changed for 40 years.

“We are much better to compensate the producers so that they leave space than blue planet, green ideas | to pay a machine that enters a river if nature does it alone. ” underlines Pascale Biron.

Ecological gains

Floral fauna and fauna surveys were made to the restored location and an upstream control site. “What we have seen is really a difference marked in terms of insects,” explains Jean-Philippe Marchand.

Spider populations, a species used to testify to the health of freshwater ecosystems, were much higher on the restored site.

Same thing for country blue planet, green ideas | birds like the Goglu of the meadows, which eat insect pests that harm cultures.

As for the flora, “we see a return, an increase, say, very progressive of the species of wetlands”, says Mr. Marchand.

The extended area also serves as a buffer zone to retain the flow of fertilizer and pesticides.

“We do not always realize the gestures that has been made in the past, which it gives as negative. It is when we find the positive that we say: “Hey! We had lost it!” », Note Judith Allard.

Suite

The researchers would now like to continue their work. by developing a retention basin near an exit of an agricultural drain where a meander was formerly. If the project goes from the front. the basin blue planet, green ideas | will become a wetland, but also an area where the water will be filtered through the sediments.

The Pot-au-butter river is a tributary of the Yamaska ​​river, considered one of the most polluted in Quebec.

“We tend to underestimate the impact of these small tributaries, the hair in a watershed. But 80 to 85 % of the length of rivers in a pool, that’s it. They are very, very small in width, but they cover huge distances, ”explains Professor Biron. “Often, we just focus on big rivers, but we forget the work that can be done upstream. Then when we work on small rivers, we see the results much faster. »»