Managing water resources to share them more effectively

Agence de l’eau Loire-Bretagne(Loire-Bretagne Water Agency), February 2023

In the Loire-Bretagne catchment area, more than half of the watercourses are experiencing water shortages, and climate projections point to growing pressures.

In light of this, the Water Agency is proposing a collaborative management approach through the Territorial Water Management Projects (PTGE) and territorial quantitative management contracts.

These tools aim to balance needs and resources by involving all stakeholders (farmers, local authorities and industry). With practical solutions (reducing water abstraction, alternative water sources, modernising distribution networks) and dedicated funding, the objective is clear: to anticipate crises, preserve aquatic environments and guarantee access to water for all.

A collaborative and resilient approach, illustrated by case studies such as that of the Sèvre-Niortaise-Mignon.

To download : partager_et_gerer_la_quantite_d_eau_-_agence_-_agence_de_l_eau_loire-bretagne_fr.pdf (760 KiB)

Quantitative water management: an increasingly pressing issue

Given the amount of water available, water abstraction is too high, particularly in water distribution areas. More than half of the watercourses in the Loire-Bretagne basin are suffering from low water levels.

Maintaining sufficient water levels in aquifers and watercourses is essential to enable the shared and sustainable use of this resource, to avoid jeopardising the survival of aquatic species, and to safeguard priority uses such as the supply of drinking water.

Climate change projections for the Loire-Bretagne basin suggest numerous impacts on the hydrological cycle from the middle of the century onwards. The expected consequences for water management are a cause for concern for the associated ecosystems and for water uses. The drought of 2022 has accelerated awareness of these impacts.

Working together to manage water supply

Working together to develop a strategy – the regional plan – and agreeing on a programme of action are key to better managing water supply when it is, or is likely to be, insufficient to meet all needs.

The regional water management plan: a strategy for sharing water

The regional water management plan (PTGE) covers all water uses. One of its aims is to implement comprehensive quantitative management of water resources, developed in collaboration with all stakeholders in the region.

It utilises various tools to achieve a balance between needs and available resources, whilst ensuring the healthy functioning of aquatic ecosystems and anticipating and adapting to climate change.

The first projects implemented in the Loire-Bretagne catchment area concern water resources for agriculture. They are being developed to cover all water uses.

Regional Water Management Plan (PTGE) : a guide (in French)

Quantitative Management Highlights – January 2023

Sèvre-Niortaise-Mignon is the first approved Territorial Water Management Project (PTGE) in the Loire-Bretagne catchment area.

Five territories, within water distribution zones, are involved in a PTGE initiative:

  • Curé (17), Clain (86) and l’Autize (85) : currently under review,

  • Cher (18) : currently being drawn up,

  • Thouet-Thouaret-Argenton (79, 49) : in the early stages.

Nine other areas, some of which are under water stress, are embarking on these PTGE initiatives:

  • Layon-Aubance-Louets (49), Boulogne-Ognon and Lac de Grand Lieu (44-85), Vie and Jaunay (85), Auzance-Vertonne and coastal watercourses (85) : expected to be completed by 2023–2024,

  • Lower Sarthe (49-53-72), Èvre-Thau-Saint-Denis (49), Lower Allier (03-63) and the Loire (42) : currently being drawn up.

The Territorial Quantitative Management Contract: a coordinated programme of action

In water allocation zones where there is a marked imbalance between water resources and usage, the Loire-Bretagne Water Agency invites local stakeholders to sign a territorial quantitative management contract. These stakeholders commit to implementing a range of solutions to become more resilient to climate change and receive financial support from the Loire-Bretagne Water Agency.

For farmers, for example, this involves improving the efficiency of water use and reducing water abstraction for irrigation by changing agricultural practices (such as choosing water-efficient crops and agroforestry) and/or production systems. The agency funds:

All these measures have been implemented under the Sèvre-Niortaise-Mignon contract, as Denis Mousseau, a farmer in the Deux-Sèvres department, explains.

Managing a strategic aquifer for drinking water

The Cénomanian aquifer, classified as a water distribution zone (ZRE), is confined over much of its perimeter. It covers a significant part of the sedimentary sector of the Loire-Bretagne basin. Its very slow recharge rate, its natural protection against pollution and its strategic importance for drinking water supply in its central area have necessitated the establishment of a management committee.

This committee monitors changes in the water table level. It commissions modelling studies to enable the planning of measures aimed at better managing this aquifer. The supply of drinking water to local authorities takes priority over economic and agricultural needs.

In certain areas, the committee recommends replacing abstractions from this aquifer with abstractions from a shallow aquifer situated above it. This aquifer is more susceptible to pollution and therefore requires protection. The Loire-Bretagne Water Agency funds these substitutions, as it does for all abstractions from aquifers in the basin classified as ZREs.

Sources

Document from the Loire-Bretagne Water Agency: Gérer la quantité d’eau pour mieux la partager - Managing water resources to share them more effectively

To go further

(In French)