Climate Change Impacts in a Colombian Andean Tropical Basin

Climate change and climate variability have a large impact on water resources. Developing regions have less capacity to prepare for, respond to, and recover from climate-related hazards and effects, and then, populations may be disproportionately affected. In Colombia, the geographical location and the marked irregularity in the terrain, give as a result, a complex climate. These factors have contributed to the water supply of the territory. Unfortunately, the visualization of abundant and inexhaustible water resources created a great disregard for them. Besides, the water supply is not distributed uniformly across the country, and then there is water-deficit in some areas as Andean Region, where the largest population and the main development centers are located. In recent decades, water conflicts have emerged locally and regionally, which have generated a crisis in the allocation mechanisms and have improved the understanding of the water situation in Colombia. The Second National Communication to CCMNU alerts on possible future consequences of climate change and the need for regional studies for understanding climate change impacts on the fragile ecosystems of high mountains as paramos and fog forest, which are water production regulators. Colombian water resources are greatly affected by changes in rainfall patterns influenced by El Niño and La Niña. The recent disasters in the 2010-2011 rainy seasons have caught the attention of not only the authorities but from the scientific community to explore strategies to improve water management by tracking, anticipating and responding to climate variability and climate change. Whereas sound water management is built upon long-term, the country is undertaking a pilot exercise for the integrated management of water resources, five Basins are selected, among them, is the Chinchiná River Basin; this Andean tropical Basin is located on the western slopes at the central range in the Andes between 4°48 and 5°12 N Latitude, at the south central region of Caldas, Colombia. It rises in the National Natural Park Los Nevados at 5400 meters above sea level and flows into the Cauca River at 800 meters above sea level. All thermal floors are found in this Basin which has an extension of only 1050 km2. This project sets out the main impacts of climate change and climate variability for Chinchina River Basin, with important impacts on water availability. The status of water resources in Colombian Andean Basins has been changing for the last decades, through more or less rainfall and changed timing of rainfall and the accelerated melting of the tropical Andean glaciers, these changes are found in the Chinchina River Basin. Besides, changes in land use and land cover affect water balance. Using the IPCC projections for the period 2010-2039 and statistical downscaling by the delta method with resolution of 1 km x 1 km, different models (HADCHM3, CSIRO y CCMA) predict different climate change trends in the Basin for scenarios A2 and B2, increasing in temperature whereas mean precipitation exhibit both positive and negative trends, which are consistent with PRECIS Regional Model. The physically based conceptual model Tetis estimated reductions in water supply, which vary depending on scenarios. If the models are correct, growing conflict over the distribution of water resources is very likely, particularly during the dry season.