Grand Étang
Réunion
Grand Étang is the largest lake on Réunion Island, located in the commune of Saint-Benoît. It was created when a lava flow acted as a natural dam, interrupting a watercourse and forming this unique natural pond. The lake covers an area of approximately 0.5 square kilometers and is surrounded by high basaltic cliffs that form a natural basin. It is fed primarily by waterfalls such as Cascade Biberon and the Bras d'Annette creek, with its water level varying significantly due to seasonal rainfall and evaporation. The lake has no natural outflow and experiences rapid changes in water depth, sometimes drying up completely during dry periods and reaching depths over 10 meters during the cyclone season. The water is volcanic in nature, with low mineralization and a slightly acidic pH. The surrounding area hosts diverse flora including tree ferns and invasive guava plants, and the lake supports a rich fauna including endemic birds like the Réunion stonechat and the island's only raptor, the papangue. Exotic fish species have been introduced, impacting native aquatic life. The nearby forest is a dense, low-altitude tropical rainforest with a complex canopy structure. Grand Étang offers a scenic and ecologically significant destination for nature lovers and hikers.
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Tip: The best time to visit Grand Étang is during the wetter austral winter when the lake is full and waterfalls are active. Visitors should consider purchasing any necessary permits or access permissions ahead of time, as the area was historically private. Hiking around the lake takes about one hour and offers opportunities to enjoy the local flora and fauna. Be prepared for variable weather and potentially slippery trails near waterfalls. No specific ticket prices are required, but visitors should respect local conservation rules and avoid introducing non-native species.
Interesting facts
- •Grand Étang is the largest inland body of water on Réunion Island, covering about 0.5 km².
- •The lake was formed when a lava flow blocked a natural river, creating a natural dam without an outflow.
- •Water levels in Grand Étang can vary dramatically, sometimes drying up completely during dry seasons.
- •The lake hosts a unique crustacean species, Streptocephalus reunionensis, which remains little studied.
- •The surrounding forest is a dense tropical rainforest with a complex canopy and is home to endemic bird species like the papangue and Réunion stonechat.
History
Grand Étang was formed by a volcanic lava flow that acted as a natural dam, abruptly interrupting a former watercourse.
Historically, the lake was private property, with ownership granted by a decree in 1896.
Over time, the lake's water levels have fluctuated significantly due to climatic conditions, with periods of complete drying and deep flooding during cyclones.
The surrounding forests and ecosystems have developed in this volcanic and humid environment, supporting endemic species unique to Réunion Island.
Place Guide
Trail Around Grand Étang
A scenic hiking trail encircles the lake, taking approximately one hour to complete. Along the path, visitors can observe diverse plant life including tree ferns and guava trees, as well as spot endemic birds and other wildlife.
Cascade Biberon
This waterfall feeds Grand Étang via the Bras d'Annette creek and is a key source of inflow to the lake, especially during rainy periods.
