increased monitoring at the Nord and Pas-de-Calais canals
The Waterways of France (VNF) network places the canals of the Nord and Pas-de-Calais departments under close surveillance, impacted by the effects of drought and heat.
While temperatures in Hauts-de-France are between 1 and 1.5°C above seasonal norms, the month of July 2022 was among the hottest ever measured in the region, the Waterways network of France (VNF) of the North and Pas-de-Calais is on maximum vigilance.
The public establishment, which manages the river ecosystem throughout the national territory, indicates that the situation is “significant”: it is tense and should not be taken lightly, but everything remains under control. Among the 680 kilometers of waterways that run through the Nord and Pas-de-Calais (10% of the national network), three tributaries are particularly in tension: the Canal du Nord, the Sambre and the Delta de l ‘Aa, where the water level is 4 centimeters lower than normal.
The risk is precisely that the water level becomes so low that the boats can no longer transport as many goods, or even can no longer be circular at all. As in Burgundy, where 54 kilometers of tracks were closed due to drought. “But fortunately for our channels, we are not there yet”, says Olivier Matrat, deputy territorial director of Voies navigables de France (VNF).
“Fortunately”, because the water in this vast network is not only used for navigation. It is also used for the protection of the environment, to ensure the irrigation of the fields or for the needs of the industries, in particular on the port of Dunkirk. It is also this dual use that adds additional tension to water levels in hot and dry conditions, as Olivier Matrat explains: “We are in a period where there is both a low water resource and higher withdrawals. Drought decreases supply and heat increases withdrawals.
We are in a period where there is both a low water resource and higher withdrawals. Drought decreases supply and heat increases withdrawals.
Olivier Matrat, Deputy Territorial Director of Voies navigables de France
VNF’s objective is therefore to maintain a balance between the water resources flowing into the canals and the different uses made of them. “VNF’s business is first and foremost hydraulic management, which is why we are mobilized on saving water resources”, indeed recalls the regional director Nord-Pas-de-Calais of VNF, Marie-Céline Masson.
120 sensors thus make it possible in real time to have data on the level of the water, then transmitted to the Regional Directorate for the Environment, Planning and Housing (DREAL) and to the Departmental Directorate for Territories and the sea (DDTM). The “water switchers” are also optimized, vigilant and present in the field, in particular to check the use of pumping.
Currently, the first lever of action is engaged: regulating water transfers via the canals, grouping boats for passage or pumping at the locks, particularly on the Canal du Nord and the Sambre. “We are in relative serenity because the situation is stable and under control,” explains Olivier Matrat, who relies on rain to stabilize the water balance: “Even that expected overnight from Thursday to Friday may have an impact.
Because the advantage of the Nord-Pas-de-Calais VNF network lies in the fact that it collects almost 80% of the runoff. Visibility remains however dependent on the weather, with control, for VNF, over about ten days.