offsetting for a hydropower project in costa rica applying the … · 2017. 7. 26. · offsetting...
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Offsetting for a hydropower project in Costa Rica
Applying the mitigation hierarchy to manage biodiversity risk
Source: world map and inset – Wikipedia.
View of Reventazon HPP © Olga Puntus/IFC (link)
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.
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
Base-load energy production rather than peak-load
Small reservoir area
Toe of the dam powerhouse, rather than distant with a long dewatered length of river. The project
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
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).
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
of the Parismina River is greater than species abundance in the section of river than will be
disconnected by the Reventazón project.
Reventazon HPP © hydroworld.com (link)
Rio Parismina (Source: panoramio.com)
Contact Details:
The Biodiversity Consultancy,
3E King’s Parade, Cambridge, UK, CB2 1SJ
www.thebiodiversityconsulltancy.com Rio Reventazon © TBC Rio Parismina© Panoramio