6.3.3 Water Management in the Vilaine Catchment
6.3.3.1 The Main Instrument Devoted to Water Management
in the Area: The SAGE Vilaine
A SAGE (Fig. 6.1, Sect. 6.2.2) is in force in the Vilaine catchment area. It is the
largest in area of any SAGE in France. In terms of territorial governance, it involves
two regions (Bretagne and Pays-de-la-Loire), six departments (Ille-et-Vilaine,
Morbihan, Loire-Atlantique, Côtes d’Armor, Mayenne, Maine-et-Loire) and 534
municipalities. An initial water management plan was enacted in 2003. It was
revised in 2015 and now includes a plan for sustainable management of water
resources and aquatic environments (PAGD), as required by the water law of 2006.
In general, issues regarding the management of the Arzal dam are closely related
to the dynamics of the water levels in the reservoir and in the river reaches influenced by the reservoir. This linkage plays an important role in the water governance
of the whole Vilaine catchment and, particularly, of the lower part of the river basin.
Three specific management issues are (i) the siltation problem in the estuary, (ii) the
management of agriculture and hunting in wetlands and (iii) the salinization of
freshwater related to the passage of the dam by boats. Following the conflicts
induced by the management of the dam, IAV proposed to build new committees to
represent all stakeholders concerned by these issues, with two initiated directly by
the SAGE Vilaine: the estuary committee and the Natura 2000 committee. The
objectives of these committees are to enhance solidarity among water users sharing
the same resources and to improve coherence between general water resources
management and drought control measures.
6.3.3.2 The Estuary Committee
Since the creation of the dam, the salinity gradient and the transfer of sediments in
the river have been heavily modified. The estuary is facing rapid siltation, with no
satisfactory solutions implemented at the moment. These ecological modifications
have impacted fishing and shellfish farming both in the estuary and in the river. The
rapid siltation prompted the creation of an Estuary Committee in 1999, which, as a
consultative body, aims to specifically address the issue of the silting of the estuary
in the Local Water Commission (LWC).
6.3.3.3 The Natura 2000 Committee
The marshes of Vilaine and Redon form nearly 10,000 ha of alluvial grasslands
upstream from the Arzal dam. These marshes were, for the most part, the inner
estuary of the Vilaine until the construction of the Arzal dams. These marshes
belong to the European site network Natura 2000, which aims to preserve
6 The Governance Context of Drought Policy and Pilot Measures …
123
6.3.3.1 The Main Instrument Devoted to Water Management
in the Area: The SAGE Vilaine
A SAGE (Fig. 6.1, Sect. 6.2.2) is in force in the Vilaine catchment area. It is the
largest in area of any SAGE in France. In terms of territorial governance, it involves
two regions (Bretagne and Pays-de-la-Loire), six departments (Ille-et-Vilaine,
Morbihan, Loire-Atlantique, Côtes d’Armor, Mayenne, Maine-et-Loire) and 534
municipalities. An initial water management plan was enacted in 2003. It was
revised in 2015 and now includes a plan for sustainable management of water
resources and aquatic environments (PAGD), as required by the water law of 2006.
In general, issues regarding the management of the Arzal dam are closely related
to the dynamics of the water levels in the reservoir and in the river reaches influenced by the reservoir. This linkage plays an important role in the water governance
of the whole Vilaine catchment and, particularly, of the lower part of the river basin.
Three specific management issues are (i) the siltation problem in the estuary, (ii) the
management of agriculture and hunting in wetlands and (iii) the salinization of
freshwater related to the passage of the dam by boats. Following the conflicts
induced by the management of the dam, IAV proposed to build new committees to
represent all stakeholders concerned by these issues, with two initiated directly by
the SAGE Vilaine: the estuary committee and the Natura 2000 committee. The
objectives of these committees are to enhance solidarity among water users sharing
the same resources and to improve coherence between general water resources
management and drought control measures.
6.3.3.2 The Estuary Committee
Since the creation of the dam, the salinity gradient and the transfer of sediments in
the river have been heavily modified. The estuary is facing rapid siltation, with no
satisfactory solutions implemented at the moment. These ecological modifications
have impacted fishing and shellfish farming both in the estuary and in the river. The
rapid siltation prompted the creation of an Estuary Committee in 1999, which, as a
consultative body, aims to specifically address the issue of the silting of the estuary
in the Local Water Commission (LWC).
6.3.3.3 The Natura 2000 Committee
The marshes of Vilaine and Redon form nearly 10,000 ha of alluvial grasslands
upstream from the Arzal dam. These marshes were, for the most part, the inner
estuary of the Vilaine until the construction of the Arzal dams. These marshes
belong to the European site network Natura 2000, which aims to preserve
6 The Governance Context of Drought Policy and Pilot Measures …
123