Diquis Hydroelectric Project and the Terraba-Sierpe Wetlands (Hnts)
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DIQUIS HYDROELECTRIC PROJECT AND THE TERRABA-SIERPE WETLANDS (HNTS) Dr. Alvaro Umaña, CATIE, INOGO. Progress Report, July 2012 DIQUIS HYDROELECTRIC PROJECT Largest hydroelectric project in Central America, 620 MW, over $2 billion. Evolved from an earlier project "Boruca" (1000 MW), which used both rivers (General and Coto Brus), had much larger reservoir and higher impact on indigenous communities. Diquis presently affects 860 hectares of indigenous lands, and 292 families (about 1,000 people ) would need to be resettled. TECHNICAL CHARACTERISTICS Consists of a 172 m high dam in Rio General, creating a 6800 hectare reservoir. A 11 km long tunnel will discharge into the Rio Grande de Terraba near Ciudad Cortes. Tunnel is 10 m diameter and has a capacity of 260 cubic m/s, operational is 200. Maximum level of reservoir is 308 masl and level can fluctuate 40 meters. Multi-level intake to help control temp. TECHNICAL CHARACTERISTICS (2) Outlet works consists of a 2.5 km channel to reduce speed and adjust temperature. Ecological flow of 20 cm/s proposed by ICE Additional 23 MW generation at the foot of the dam uses 2 cm/s. Only 2 km dry. Rio Coto Brus is 40% of Terraba flow, low 20 cm/s, average 300, high 4000-5000. Operational level of Diquis in dry season is 200 cm/s, so total flow would be 240 cm/s ENVIRONMENTAL IMPACT ASSESSMENT Process followed by ICE: 1) Social-environmental baseline studies 2) Identify impacts. 3) Predict and value impacts. 4) Propose mitigation or compensation measures. 5) Formulate a management plan. 6) Integrate EIA components and present to SETENA (Now expected January 2013) ICE BASELINE STUDIES ICE has completed basic baseline studies: Zooplankton- Dr. Alvaro Morales CIMAR Primary productivity- CIMAR Fish,Reptiles, Biocides (Bromacil 5ug/l) Detailed land-use maps of HNTS, more focused on impact area. In general ICE has excellent information about HNTS. Impact modeling ongoing: salinity, sediments, flow regimes. MAIN IMPACTS Changes in the flow regime:project would generate at capacity in dry season, so minimum flow would be 240 cm/s. It is estimated that half the sediments will be retained by the dam, so there is a net reduction in sediment loads. Temperature increases in water to be handled by multi-level intake structure and outlet works. THE TERRABA-SIERPE WETLANDS Térraba-Sierpe wetlands (25,000 ha) are the largest in the country and they include three different types of ecosystems: mangroves and palm an cerillo forests. They are a RAMSAR site. Terraba mangroves considered main impact area of Diquis, studies focused here Preliminary estimates (UCR) place mangrove loss due to Diquís at 315 ha. TERRABA-SIERPE WETLANDS (2) Population inside the reserve: 400-500 people, about 150 piangua collectors.. Management plan soon to be published but already outdated. GRUAS recommends expansion to fill vacuums like Isla Violin. Many threats: drug trafficking, agricultural expansion, acuaculture, palm, forest fires. Reserve presently has 5 people, including director, one boat and budget of $60K/yr. COMPTROLLER GENERAL REPORT ON RAMSAR SITES Includes Caño Negro and Térraba Sierpe Strongly criticizes government for not following RAMSAR Convention guidelines. Specifically it points out to lack of management plans, weak or non-existent control, invasions to these areas (1700- 3000 ha), and lack of geographic information systems. MINAEM lacks adequate resources for area IMPACT FROM CHANGES IN FLOW REGIME Water flows into wetlands range from 45 to 400 cm/s, Diquis would add 200 in dry season. Seasonality of flows would be changed but Rio Coto Brus not affected. Macro-events like hurricanes are critical for sediment loads. Potential ecological impacts on productivity of the mangrove needs to be monitored. IMPACTS OF SEDIMENTS UNCERTAIN Diquís dam is expected to retain 50% of the sediments. Increased sedimentation has been a growing threat to mangrove, it is not clear what the impact of a reduced sediment load from the reservoir is. UCR studies acknowledge this. ICE argues that retention of sediments at the reservoir might even be beneficial. FUTURE OF DIQUIS UNCERTAIN Project status is uncertain and negotiations are difficult because of several factors: 1) Consultation process still undefined. 2) EIA delayed by more than one year. 3) ICE internal planning includes scenario without Diquís. 4) ICE financial situation deteriorating and levels of indebtedness increasing 5) Regional electricity market slow to develop INDIGENOUS PEOPLE CONSULTATION Costa Rica is a signatory of ILO Convention 169, which requires mandatory consultation to indigenous people. Negotiations between ICE an indigenous people have been complicated and UN negotiator James Anaya visited CR. Diquis Commission (presided by VP Piva) has not decided on type of consultation (referendum, open meetings, individual) KEY PARTNERS OSA Conservation Area/ SINAC/ Park Person. University of Costa Rica CIMAR Independent multidisplinary group BIOMARCC Project- GIZ funded effort * Carbon sequestration study Comptroller General effort on RAMSAR sites Blue Moon Foundation: $2.3 million proposal presented 2 years ago. Need to reactivate contacts. CHALLENGES AND OPPORTUNITIES HNTS is at a critical juncture, INOGO can attract attention to problems and catalyze some solutions. SINAC and ACOSA critical. Assessment of GRUAS recommendation and potential expansion of the area. Build coalition with partners, including ICE and create atmosphere of cooperation and information sharing. BIOMARCC, Blue Moon Help attract international attention, Blue Carbon, etc. OTHER RELEVANT STUDIES UCR has published a set of studies conducted by faculty on different areas of the project. Most relevant is Dr. Daysi Arroyo study on potential biological impacts of Diquis. Earth Economics study for Univ. of Vermont in 2010 valued 150,000 ha of forests in the area, including the Térraba-Sierpe ($2,000-18,000/ha). Basic reports Aproximaciones al Megaproyecto Hidroeléctrico El Diquís. Grupo Multidisciplinario, UCR, Marzo 2012 Documento para la Oficialización del Plan de Manejo del Humedal Nacional Térraba-Sierpe, ACOSA, TNC, UCI, ELAP, San Jose, Enero 2008 Informe de Auditoría Operativa Acerca del Cumplimiento por parte del Estado para Protección de los Humedales (Convención RAMSAR), Contraloría General de la Rep, 2011.