Drought in the Lot: why the March rains won’t be enough

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It is common to talk about drought in summer, less so in winter. At Lotto the situation remains complicated, the prefecture and professionals are on the alert.

As soon as the first drops fell, Lot already felt better. However, the game is far from over on the drought front. And the fate of the rivers remains in the hands of the sky, or rather of its rainfall… So much so that an operating committee coordinated by the Dtt and the prefecture of Lot is expected today.

“Usually, we install our river surveillance later in the season, generally during the month of April. But the observations of the resources are worrying,” underlines Jean-Pascal Lebreton, director of the DDT of the Lot.

If no restrictive measures have been taken in the area for the moment, the readings at the beginning of March were not encouraging.
On the Célé subject to drinking water collection, the flow rate remains low. “In February, notes Bernard Laborie, president of the mixed union, the average flow was 5.24 m3/second, against 18.60 in February 2022”.

On the Lot, at the beginning of the week, the water level remained low for the season.

Finally, rainfall made its first appearances last week, touching 70 mm in particular in Figeacois, at a time when the departmental authorities have not ruled out taking more restrictive decisions on the basins. This is what the prefecture of Lot communicated to us on Friday: “Natural winter supplies did not take place, the levels were until then extremely low on some rivers. This inventory of about twenty observed perimeters, we usually do it between April and June, not already in March. On the Lot and Dordogne rivers, the level of upstream reserves varies from medium to low, with a filling of 60 to 70%. These tensions in the Lot area are worrying”.

“Our rivers have had a pretty strong response to these rains”

This is the analysis also shared by the Syndicate Mixte de la Dordogne Moyenne et de la Cère Aval (SMDMCA), where Thomas Etien, the river technician, is closely monitoring the development. “The water flows have been insufficient for some time now. We are a month or two ahead of the low tide season, compared to previous years. If we have to arrive in the summer period with these flows we will experience a situation that we have rarely experienced. The rains must fall in spring, otherwise it will be catastrophic,” warns the river technician.

Read also:
Drought: prefects called to issue water restriction orders “from now on”

With the downpours, the rivers have swollen well, but the mirage may not last. “Our rivers have had a fairly strong response following these rains,” notes Jean-Pascal Lebreton. “We no longer see the situation this week under the same prism as last week. However, infiltration on very dry soils does not work as well, and with this thaw the beginning of vegetation is heralded”, fears the DDT manager.
Everyone agrees that spring rains won’t reach winter, because the water that’s currently falling won’t necessarily reach groundwater. When vegetation wakes up, it will capture this surface water.

Read also:
Drought: the Célé river is already at a minimum in Figeac, a sad record since 1950

However, a few heavy and regular downpours, which fall at the right times of spring and summer, would be enough for everything to not go so badly in the end. Except that weather forecasting remains a random science…
To ease everyone’s concerns about the state of drought, the director of the Lot DDT therefore recalls that “the underground network of the Lot is particularly dense. Our aquifers in this karst soil expose us much less than other territories. Interconnections to guarantee drinking water connections and networks are also an important strategy, in the face of the risk of water scarcity. Given our Lot supply plan, we have a pretty solid network.”
The future will tell, in the meantime everyone is scrutinizing the sky…

In August 2021, the wetland regained its splendor after the works.

In August 2021, the wetland regained its splendor after the works.
Photo authorized by the SMDMCA.

Preserving the resource also means saving the wetlands of the Lot

The fear of river professionals is that of extremely low water flows, to the point of causing flow interruptions, particularly harmful to the life of watercourses. “The fish fauna would be strongly affected, both by the lack of water, but also by its warming. Faced with abnormal increases in water temperature, we could face lethal levels for fish. cash”, worries Thomas Etien, l SMDMCA agent.

  • The miracle can also come from the earth

Not everything is irreversible. As part of the protection of wetlands, real sponges of our soils, it is possible to restore them. “Since the 1970s, wetlands have been reduced, dried up. The ones we have lost have been lost by man, not by climate change,” explains Thomas Etien.

It is by the will of man that they will be preserved. Thus, the same applies to the Castagné peat bog, in the Sousceyrac sector in the Quercy (Calviac). Under this management plan led by the SMDMCA and agreements made with the ONF and a farmer, this wetland has benefited from drainage removal works and the establishment of dynamic rotational grazing.

  • National winner of ecological engineering in 2020

“The data recorded by a water level probe placed in the heart of the wetland have made it possible to obtain hydrological monitoring of the site. The results are extremely positive. The water levels detected show a rise in the roof of the aquifer and maintained at its maximum level during the winters of 2019-2020 and 2020-2021, which was not the case before (2018-2019) The records also show less pronounced drying during the summer of 2020, despite record temperatures. In 2021, the level of humidity has always remained at its maximum, despite a spring drought.”

This operation of the mixed union of the Pays de la Vallée de la Dordogne even obtained the National Prize for Ecological Engineering 2020, category “restoration of ecosystems and populations, during the national biodiversity meeting, on October 8, 2020 in Massy.

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