El Salvador has 58 basins which serve as the surface collection of fallen water in the form of rain and as a peculiarity all drain to the coast of the Pacific Ocean, among the most important basins is that of the river Lempa, in whose main channel have been Built three hydroelectric power plants: Central Hydroelectric Cerron Grande, Hydroelectric Central September 15 and Central Hydroelectric November 5, these structures have notably modified the channel and the natural landscape of the river and consequently that of the basin, as well as the Central Hydroelectric Guajoyo , Drains the agiuas of la Guija and incorporates them to the bed of the river Lempa. Another of the important basins is that of the Rio Grande de San Miguel which is the basin of the largest hydrographical basin that is fully understood within the Salvadoran territory. El Salvador shares with Guatemala the basin of the Paz and Lempa rivers and Honduras Lempa and Goascoran.