A drought caused by El Nino exposes the bed of the El Cisne lake in Colombia, July 31, 2014.
President Juan Manuel Santos made the declaration on Wednesday on the request of Institute of Hydrology, Meteorology and Environmental Studies (IDEAM).
The decision was made in the wake of a drastic drop in water levels in the two key rivers of Magdalena and Cauca, which supply hundreds of towns and cities in the South American country.
This is while a fifth of Colombia's municipalities are already under water rationing measures amid the El Nino phenomenon and an ensuing dramatic reduction in rainfall.
The phenomenon also forced the government earlier this week to declare a red alert for forest fires burning across the Andes Mountains.
The Colombian Environmental Ministry said the forest fires are a consequence of drought and rising temperatures across Colombia. The red alert applied to 80 percent of the country.
El Nino, a key weather pattern, occurs every seven to eight years when ocean waters become exceptionally warm and distort weather conditions across the globe.
It is characterized by the warming of surface waters particularly in the tropical eastern Pacific Ocean, which is connected with drought in Southeast Asia and Australia and heavy rains in South America.
Wouldn't they be considered part of the Amazon RIver system that's had this 'drought' problem for a few years now?