« Landscape pre-diagnosis » for floating photovoltaic park project, Lac de Mondély, Ariège

Commissioned by ATESyn (Plateforme d'ingénierie environnementale) based in Ariège, our landscape architects carried out a pre-diagnosis in July 2020, as part of a data collection and field campaign. The aim was to carry out an analysis and describe the organization of the region in order to identify, evaluate, spatialize and prioritize the landscape issues facing the area under study, located around Lake Mondély in Ariège.

A brief history of the dam and lake's construction and significance.

The Mondély dammed lake was filled in December 1980 and is located in the Ariège department, bordered by the communes of La Bastide-de-Sérou, Gabre and Aigues-Juntes. The lake is accessible by two roads from Le Mas-d'Azil and La Bastide-de-Sérou.

It is fed by the Lèze, a river flowing between the Arize massif and the Plantaurel mountain range. Construction of the dam began in May 1979 and took 2 years to complete.
Lac de Mondély is a dammed lake designed to supply water to farmers downstream, and to support the Lèze during low-water periods by releasing water into the river. The 3.5 million m3 lake irrigates 1,700 hectares.

It is also used to irrigate the Lèze valley, along a 55 km stretch, first in the Ariège département, then in the Haute-Garonne. It is filled by a watershed area of 13.6 km2.

Low-water level support for the Lèze, a lowland river characterized by low modulus, gives rise to significant variations in water level, which can, in the case of very dry periods, lead to much of the reservoir surface drying up.

The site was listed as a “Natural Area of Ecological, Faunistic and Floristic Interest” by the French Ministry of Ecology and Sustainable Development in 1989. It is an ornithological observation site.

Description of lake management

The Syndicat Mixte d'Aménagement Hydraulique de la Lèze (SMAHVL, more often referred to as SMAHL) owns and manages the Mondély dam, which is therefore a non-state-owned lake, privately owned by SMAHL.

The SMAHL, a consortium made up mainly of farmers, operates and manages the dam and water releases.
Each management entity is assigned a maximum volume that can be withdrawn during the low-water period, which runs from June 1 to October 31. The winter period runs from November 1 to May 31.

History of the floating photovoltaic park project

The SMAHL owns the lake and a 4-meter dry land perimeter around the lake above the highest water level (50 hectares at lowest, 60 hectares at highest).
SMAHL decides to use part (minimum surface area of 10-15 hectares, maximum surface is around 20 hectares) of the lake's surface area to generate electricity for re-injection into the public grids downstream of the dam.

As a first initiative, the connection could be made in the reservoir’s northern sector, toward the town of Sabarat, via a network installation present in the town of Gabre.
The SMAHL called on “EDF Renouvelables” to propose a project.
EDF Renouvelables France entered a contract with SMAHL to carry out the studies and procedures required to design the project.

As part of the Lac de Mondely project, based in the communes of La Bastide-de-Serou, Gabre and Aigues-Juntes in the Ariège region, EDF Renouvelables France called on the services of a competent service provider, La Fabrique Terrestre Aquatique et Aérienne, to carry out a landscape analysis of the initial state and then the landscape area where impact study would be registered for a floating photovoltaic park project.

The photovoltaic project as a regional project

Led by SMALH this energy project’s communication can be put in place to explain the ins and outs of SMALH's work and about the lake itself (water system, relationship between the river’s upstream and downstream).

By involving the local population and associations in early stages of the project, it enables an understand about the many activities that take place on and around the lake, such as fishing and supervised swimming in summer, even though boating is prohibited.

La Fabrique terrestre, aquatique et aérienne : Project team : Christina Ottaviano, Christophe de Saint Just.

Iconographic credits : DR, Droit Réservé, : Christina Ottaviano, Christophe de Saint Just ;

https://WWW.youtube.com/watch?v=s-dyGnZsbe8 http://atesyn.fr/missions/amenagement-du-territoire/