AES Tietê S.A., is a Brazilian electrical energy generator, that owns and operates ten hydropower plants in the State of São Paulo, Brazil. These hydropower plants are located in the Tietê river basin, the Grande river basin, the Pardo river basin, and the Mogi-Guaçu river basin. In the early 1900s, these once-forested river watersheds became a gateway for agricultural activities, and they were subjected to deforestation for planting and cattle ranching. During the reservoirs’ construction, land around the reservoirs was subjected to floods and continued cattle ranching and agribusiness such that any remnants of original tree vegetation completely disappeared.
In 2001, AES Tietê initiated reforestation activities with native species to protect the riparian areas bordering its reservoirs, testing the viability of different afforestation/reforestation practices. Between 2001 and 2007, AES Tietê reforested about 1,568 hectares of non-contiguous lands along the reservoirs. The results demonstrated that the riparian areas will only regenerate forest cover through human interventions as the areas were no longer able to regenerate naturally, and therefore required reforestation activities to restore the forest.
The AES Tietê Afforestation/Reforestation project has reforested 2,001.2 hectares riparian areas along the banks of AES Tietê’s ten hydropower reservoirs with native forest species. This project used a mix of native tree and shrub species, selected based on their traditional occurrences within the reforested areas, as well as their ability to provide a long-term sustainable riparian forest habitat. As a result, the ecosystem has moved towards restoration, biodiversity is increasing, and the local residents are experiencing numerous environmental and social co-benefits.
The project’s restoration of the riparian forests is demonstrating a re-emergence of ecosystem services, such as carbon sequestration, controlled soil erosion, and land-degradation reversal. Soil erosion effects such as sedimentation and water pollution, have reduced because these riparian buffers act as filters by delaying, absorbing, or purifying contaminated runoff before it enters the water. The restored areas are storing and recycling organic matter and nutrients, providing habitats for fish and wildlife, and removing nitrogen, phosphorous, and sediment from surface and subsurface water flows.
Social and Community Benefits
The project has provided employment and recreational opportunities for local residents, as well as improving the aesthetic quality of the areas. The enhanced marine ecosystems have re-established traditional sources of value, such as fishing and withdrawal of water for drinking and irrigation. The project also promotes the safety of local residents. The reforested areas mitigate flooding, and the project is deterring additional settlements and construction on eroded riparian lands, which have a high risk of landslides and flooding-related disasters.