Ecological Design of Dams: The Diquis & Savegre Hydroelectric Projects in Costa Rica
At this one-day workshop on May 3, 2013, dam design and operation experts met with representatives from the Costa Rica’s government-run electricity and telecommunications services provider to explore the potential for ecological design and operation of dams, specifically Costa Rica’s planned Diquis and Savegre hydroelectric projects.
On the one hand, dams hold the promise of green energy that forgoes fossil fuels. On the other hand, dams can cause a variety of ill effects, including the alteration of important functions of wetlands, important breeding grounds and nutrient sources.
The Stanford Woods Institute and the Osa and Golfito Initiative recently hosted a workshop to explore the potential for ecological design and operation of dams, specifically Costa Rica’s planned Diquis and Savegre hydroelectric projects. Dam design and operation experts met with representatives from the Costa Rican Electricity Institute (ICE is the Spanish acronym), the country’s government-run electricity and telecommunications services provider, to discuss potential challenges and opportunities.
With both increasing national energy demands and the move toward a regional energy market, the pressure is on ICE to design and develop additional sources of energy. However ICE is not just interested in designing their dams for maximum energy production, its goal is also to generate the best possible social and environmental outcomes for all involved.
Costa Rica is considering a number of large infrastructure projects in the southern part of the country. These projects include two large hydroelectric projects that drain into wetlands, the Diquis and Savegre projects.
The Diquis Hydroelectric Project is the largest, with an expected investment of more than $2 billion. It is the product of several decades of research, and it includes several ecological design characteristics. This 631 MW project would create a 6800 hectares reservoir, and it would require about 750 hectares in two indigenous reserves. Costa Rica is a signatory to ILO Treaty 169, and therefore the government must promote a transparent and representative consultation process.
This has not happened yet, and the Costa Rican government created a Diquis Commission, headed by Vice President Alfio Piva, to define who should be consulted and to oversee the process.
An important aspect of this initiative is that Costa Rica is not merely aiming for the minimum acceptable standards for the project, but instead will focus on how to generate the best possible social and environmental outcomes for all the stakeholders involved. In this sense the initiative will focus on better or more intelligent approaches and designs, where applicable, and also on how these infrastructure projects can provide benefits and development opportunities to local populations.
The Diquis project will discharge approximately 200 cubic meters per second of water into the Grande de Terraba river during the dry season, ten miles upstream from major mangroves, which are protected under the Ramsar Convention. During the dry season the river will have a normal flow of 40 to 50 cubic meters per second, so the project will have a significant impact in shifting the hydrograph and salinity profiles of the river which could ultimately affect the productivity of the mangrove.
In the specific case of the Diquis project, special consideration should be given to the fact that this is a protected area under the Ramsar Convention, so in addition to the national legislation, the project must also satisfy the mandates of this convention. Signatories to this treaty are able to make changes to the areas that they have designated, but justification and potential compensation alternatives must be considered.
The Osa and Golfito Initiative, a program of the Stanford Woods Institute for the Environment, is currently undertaking a case study on the Diquis Dam. Since the proposed dam on the Savegre River shares many characteristics of the Diquis Dam, the Savegre was also included in the workshop.
The workshop brought together Costa Rican and American experts in topics such as dam operation, sedimentation, dam design, wetlands and estuaries to discuss the dams’ potential environmental impacts on estuaries, and, in the case of the Diquis Dam, a wetland protected under the Ramsar Convention, an international wetland conservation treaty.
Participants discussed innovative modeling tools, including ways to better understand the dams’ impacts on salinity and downstream ecosystems. Designing for the dams’ eventual decommissioning and factoring this into cost calculations highlights the role that experiences with older dams around the world can play in a country like Costa Rica, where the oldest dam is 50 years old – relatively young by global standards – and no dam has yet to be decommissioned.
While there are ongoing deliberations in Costa Rica regarding the impacts that the Diquis Dam would have on indigenous people of the region, an extremely important challenge, this meeting focused solely on the design and operation of the dams.
Objectives of the Workshop
The workshop had three main objectives:
- Examine relevant lessons from the ecological design of dams and minimization of environmental impacts, with a particular emphasis on hydrological and water quality modeling needed to attempt to predict potential damages mangroves
- Analyze the legal implications and options open to Costa Rica under the Ramsar Convention
- Explore options for operational changes to hydroelectric projects (e.g., the possibility of shutdown during certain periods at night) to reduce the impacts on mangroves and other ecological impacts