With more than 247,000 acres of mangroves, salt and freshwater marshes, Costa Rica’s lower Tempisque River basin is one of the largest wetland systems in the Central America Pacific lowlands. But to the dismay of many ecologists, the basin has also become one of the country’s most intensely farmed areas, accounting for almost all of the melon, half of the sugar cane and a third of the rice production in Costa Rica.
In their quest to convert a floodplain into farmland, engineers constructed 18 miles (30 kilometers) of dikes along the river and dredged more than 12 miles (20 kilometers) of the river basin. Their work, plus agrochemical contamination, has destroyed some 35 percent of the original wetlands and 60 percent of Tempisque’s riparian forests, according to data collected by the Organization for Tropical Studies (OTS) — a consortium of US and Latin American universities.
OTS recently joined forces with several national and international organizations to undo some of the damage and prevent further destruction. The project, called the “Initiative for the Management of the Lower Tempisque River Basin”, is working to improve the river basin’s management, generate scientific information for decision makers, encourage sustainable farming, and restore ecosystems.
The initiative is funded by the Costa Rica-United States Foundation for Cooperation (CR-USA), Avina Foundation, U.S. Fish and Wildlife Service and Ducks Unlimited Inc. Local organizations participating in it include Costa Rica’s National University, Technological Institute, National Learning Institute, National Water and Irrigation Service, Tropical Science Center, University of Costa Rica and National System of Conservation Areas.
“We plan to lay the groundwork and obtain the basic information needed to define the wetlands in the Tempisque River Basin and, above all, to demonstrate their ecological value and — as far as possible — the financial value of their ecology,” says Eugenio González, OTS co-coordinator of the project.
The initiative involves establishing a geographic information system based on environmental, social, and economic data of the area; training in sustainable agriculture for local governments and small and medium-sized farmers; water quality monitoring; and wetlands restoration. González admits that the lower Tempisque river basin is so degraded that it may be impossible to restore the ecosystem to its condition prior to agro-industrial development. He does, however, hope that the research will provide information so that fees can be levied for the environmental services the ecosystem provides, such as providing water to rice farms.
Marco Solano, coordinator of the environment ministry’s National Program for Wetlands, notes that the quality of the water provided by the river basin is directly related to the ecosystem’s overall health. He adds that the lower Tempisque, which encompasses part of Palo Verde National Park, is considered an ecologically unique site, due to the large concentration of birds in the area. However, dredging and diversion of the Tempisque for crop irrigation have adversely affected the system’s plants and wildlife. Solano points out that healthy wetlands provide such benefits as recharging aquifers, purifying water, sheltering wildlife and generating timber and natural fibers.
González, who is also the director of the OTS biological station in Palo Verde National Park, adds that the park is not only the most important migratory bird site in Central America, but also counts on more wetland-management and conservation research and studies than any other area in the tropics. The park, together with several nearby protected wetlands, has been designated a “wetland of international importance” under the Ramsar Convention.
One of the project’s early accomplishments has been the re-establishment of natural water flows in Palo Verde, thanks to collaboration by the environment ministry and Technological Institute. The restoration led to a steady increase in the number of resident and migratory birds, according to OTS data. At last count, in January 2003, there were 20 species of aquatic birds, some of which numbered in the thousands.
Communities near the Tempisque have had their share of problems caused by the intense agricultural development. César Gutiérrez, a founding member of the Association for the Lower Tempisque River, claims the communities of Ortega and Bolsón have suffered because the dikes built for sugar cane irrigation have caused serious flooding during the rainy season and drought during the dry months.
Together with other affected communities, the people of Ortega y Bolsón received technical assistance from organizations such as the National University to control the flow of water during the dry season. For example, they have built water gates to sustain the water level during the dry months and protect the areas where there was considerable water filtration.
“From our point of view, restoration depends on the actual participation of people and isn’t just a matter of undertaking projects. Communities need to be involved,” Gutiérrez emphasizes. He explains that reducing the flooding and droughts in Ortega and Bolsón helped created an important destination for birdwatchers. Now, aquatic birds such as the jabiru (Jabiru mycteria), roseate spoonbill (Platalea ajaja) and white ibis (Eudocimus albus) are visiting the area in increasing numbers.
In addition to wetlands restoration, the Initiative for the Management of Lower Tempisque River Basin aims to integrate agriculture with the environment which, according to González, is no small task. Hundreds of tons of rich alluvial soil have been lost from farms due to poor management of land and water. As part of the project, local farmers will receive training in how to better manage water and soils. The National Training Institute is also helping small farmers produce organic rice and install a bio-factory for growing pathogenic mushrooms to be used instead of chemical pesticides. They are also making paper from invasive cattails (Typha dominguensis), which are being removed from Palo Verde’s marshlands as part of the restoration process.
González says that one of the initiative’s products will be a baseline document for decision makers, which will be developed during the next five years. That document, he says, should help ensure the survival of the most important wetlands of the Mesoamerican Pacific.
— Katiana Murillo
Contacts in Costa Rica:
Initiative for the Management of Lower Tempisque River Basin
Tel 506/ 651-8165
Read more about this project in the Eco-Index: