Offsetting for a hydropower project in Costa Rica Applying the mitigation hierarchy to manage biodiversity risk
Overview Most hydropower projects are likely to have residual impacts that require offsets to reach international leading practice standards (e.g. IFC PS6). The Reventazón HPP has pioneered the use of metrics to plan no net loss with the Parismina River Offset , setting a best-practice standard for other HPPs in Costa Rica and globally. This is perhaps the first direct offset of the impacts of a HPP on a river ecosystem, demonstrating that no net loss HPPs are feasible under certain conditions. However, it is important to highlight that no net loss is much more feasible for certain HPP designs and environmental conditions, e.g.: Run-of-the-river, rather than storage Upstream in the watershed, rather than downstream Downstream of existing HPP Source: world map and inset – Wikipedia. Base-load energy production rather than peak-load Small reservoir area The project Toe of the dam powerhouse, rather than distant with a long dewatered length of river. Name: Proyecto Hidroeléctrico Reventazón Hydropower Plant (HPP) Developer: Instituto Costarricense de Elecricidad (ICE) Location: Reventazón River, medium-sized, flowing into the Caribbean in Costa Rica Details: 305 MW - largest renewable energy project in Central America. 130 m dam, flooding of a 6.9 km2 area, creation of an 8 km long artificial lake. Downstream of Angostura HPP Investment: International Finance Corporation (IFC), Inter-American De- velopment Bank (IADB) and others
View of Reventazon HPP © Olga Puntus/IFC (link)
The challenge IFC Performance Standard 6 PS6 is for ‘Biodiversity Conservation and Sustainable Management of Living Natural Resources’. PS6 requires an assessment of Critical Habitat-qualifying features and assessment of Natural and Modified Habitat. PS6 requires net gain of Critical Habitat-qualifying features, and no net loss of Natural Habitat. Net gain and no net loss are achieved using offsets and additional conservation actions. Offsets are a measure of last resort to address residual impacts on biodiversity and ecosystem ser- vices, after all other components of the mitigation hierarchy have been fully applied (see right).
The mitigation hierarchy – TBC graphic
Key biodiversity and impacts The Reventazón River qualifies as Natural Habitat according to IFC PS6. Potential impacts include: loss of 8 km of flowing river, a barrier effect on migratory fish species entering 38 km of Reventazón River mainstream and tributaries downstream of Angostura HPP; changed hydrology (sedimentation and water quality) in downstream Reventazón River, including Tortuguero National Park. Offsetting was required to: Compensate for project impacts on the Sub-Corridor Ensure no net loss of river Natural Habitat, and Compensate for impacts on migratory fish species. Reventazon HPP © hydroworld.com (link)
Offsetting for no net loss of Natural Habitat The Parismina River was identified as equivalent to the Reventazón River (like-for-like). This is an averted loss offset - no HPP will be developed on the Parismina River in the future. Method 1: ‘quality x length’ metric for structural connectivity. No net loss is achieved when (in simple terms) water quality with offset actions in the section of the Parismina River that would have been disconnected if a Parismina dam was constructed, is better than the water quality in the section of river than will be disconnected by the Reventazón project. Method 2: a metric for functional connectivity of the river system, based on the abundance of indicator species.
No net loss is achieved when with offset actions, species abundance in the relevant sections Rio Parismina (Source: panoramio.com) of the Parismina River is greater than species abundance in the section of river than will be disconnected by the Reventazón project.
Contact Details: [email protected] The Biodiversity Consultancy, 3E King’s Parade, Cambridge, UK, CB2 1SJ Rio Parismina© Panoramio Rio Reventazon © TBC www.thebiodiversityconsulltancy.com