Manual de Plantas de Costa Rica | The physical environment| 63 
Amarillo, which send the rest of their waters into the Rio Sarapiqui and the Rio Tor- 
tuguero, respectively. Here, it should be pointed out that, confusingly, three major 
Costa Rican rivers bear the name “Rio Chirrip6.” Two of these drain opposite slopes of 
Cerro Chirrip6, the highest mountain in the country, in the Cordillera de Talamanca. 
These are here termed (in this chapter and throughout the Manual) the Rio Chirrip6 
Atlantico and the Rio Chirrip6 Pacifico (known downstream as the Rio General and, 
further yet, as the Rio Grande de Térraba). The third Rio Chirrip6, with no fluvial con- 
nection to the cerro of the same name, is located in the Llanura de Tortuguero (see 
below) and is not further qualified. 
That portion of the Caribbean coastal plain lying between the basins of the Rio 
Sucio and the Rio Reventaz6n is known as the Llanura de Tortuguero. The important 
rivers traversing this sector are the Rio Chirrip6, Rio Suerte, and Rio Tortuguero, which 
receive (via the Rios Sucio and Toro Amarillo) waters from the eastern half of the Cor- 
dillera Central. The so-called Llanura de Santa Clara, extending south to near Puerto 
Lim6n, is crossed by the Rio Reventaz6n (known in its upper reaches as the Rio Grande 
de Orosi) and its tributaries, including the Rio Jiménez and Rio Parismina, as well as 
the Rio Pacuare, Rio Barbilla, and Rio Chirrip6 Atlantico. The two last-mentioned 
rivers merge downstream to form the Rio Matina. Collectively, the rivers of the Llanura 
de Santa Clara drain the eastern end of the Cordillera Central, the eastern portion of 
the Central Valley (Cartago and vicinity), and the northern half of the Cordillera de 
Talamanca. 
All of the Caribbean coastal plains mentioned above, known collectively as the 
Limon Basin, are dotted with isolated to clustered hills and ridges up to several hun- 
dred meters in height. Some of these (e.g., Cerro Tortuguero) represent extinct volcanic 
structures. South from Puerto Limon, the coastal plain is very narrow. The southern half 
of the Cordillera de Talamanca is drained by several rivers, including the Rio Banano, 
Rio Estrella, Rio Telire, Rio Coén, Rio Lari, Rio Urén, and Rio Yorkin. Except for the 
first two (which flow directly to the sea), all of these merge to form the Rio Sixaola, 
which enters the sea at the Panamanian border. 
The Pacific slope 
Costa Rica’s Pacific slope lacks the broad coastal plains characteristic of the Caribbean 
slope. The Rio Tempisque basin, at the northern end of the country in Guanacaste 
Province, is the most extensive lowland region on the Pacific side. The Rio Tempisque 
empties into the head of the Gulf of Nicoya, collecting the waters of its many tributar- 
ies, including the Rio Ahogados, Rio Liberia, Rio Tenorio, and Rio Corobici (the last 
two of which merge downstream to form the Rio Bebedero). This system drains the 
northern end of the Nicoya Peninsula, most of the west slope of the Cordillera de Gua- 
nacaste (including the Meseta Volcanica de Santa Rosa), and the northern end of the 
Cordillera de Tilaran. Scattered throughout the Rio Tempisque basin are wetland habi- 
tats (marshes and lagoons) of seasonal importance. 
