Photo courtesy of Efrain Gonzalez Buitrago/flickr.

BOGOR, Indonesia (24 August, 2011)_The domination of water-dependent energy generation in Costa Rica is currently under threat as climate change depletes fragile water resources located in the country’s lush, green forests. Understanding the ecosystem services these forests provide to the hydroelectric sector will be critical to help researchers identify priority conservation and restoration areas, says a recent study from the Center for International Forestry Research (CIFOR).

Hydroenergy is the process of generating electricity through the force of flowing water either from rivers or pumped through man-made dams. It is the most widely used form of renewable power and boasts considerably lower carbon emission levels than fossil fuel power plants. Water plays a critical role in Costa Rica’s growing sustainable energy sector, with more than 80 percent of its electricity provided by hydroelectric plants alone.

Water is equally crucial to neighbouring Nicaragua, whose rather modest hydroenergy sector is set to explode with 40 plants currently under design to reduce the country’s dependence on imported fossil fuels.

“Hydroelectric sectors are directly dependent on hydrological ecosystem services provided by forests, like regulating water quantity and reducing soil erosion,” said Raffaele Vignola, a scientist with Centro Agronómico Tropical di Investigación y Enseñanza (CATIE) in Costa Rica and co-author of the study.

With this in mind, which are the most important forest areas to conserve or restore in each country to ensure a sustainable hydroenergy sector? Bruno Locatelli, CIFOR and CIRAD scientist and lead author of the study, answered this question using a new approach to ecosystem service mapping.

“Because of the complexities of economic and ecological systems, it can be very expensive and sometimes just impossible to quantify an ecosystem service and the benefits it generates at a national scale. Coupling economic models of water users with hydrological models is challenging enough without the scarcity or sheer diversity of data that often comes with attempting to map an entire country’s catchments and water use,” said Locatelli.

Locatelli and his team developed a simpler method for mapping ecosystem services provided to the hydroelectric sectors. The method takes into account the different abilities of different ecosystems to provide different services, and identifies hotspots for conservation or restoration to ensure these services continue to be provided. The method involved interviewing Central American experts from the hydroenergy sector and from research centres and universities, and using “fuzzy logic” to turn their responses into numbers.

“Expert local opinion was combined with information collected by energy companies, ministries and national organisations on the hydroelectric plants (both dams with reservoir capacity and run-of-river plants). This information was plugged into an equation that made it possible to calculate the utility of all ecosystems in the country for the whole hydroelectric sector,” explains Locatelli.

In both countries, one river basin emerged as a clear major priority for both conservation and restoration, given the services provided to the hydroelectric sector. In Costa Rica, the Reventazon river basin had 31% and 26% of the total priority areas for conservation and restoration respectively, even though it covers just 6% of the country.

In Nicaragua, the Matagalpa river basin holds 65% and 77% of the priority areas for conservation and restoration. The central part of the river basin is more suitable for conservation, the study concludes, because it is still covered by forests, whereas restoration priorities are more evident in the southern part.

The hydroelectric sectors in both countries can use the information generated by this approach to safeguard the quality and quantity of water for future energy supplies and sustainable development, allowing them to continue to work towards carbon neutrality.