Hydrological modelling with TOPMODEL of Chingaza páramo, Colombia

Eydith   Girleza Gil; Conrado   Tobón

Hydrological modelling with TOPMODEL of Chingaza páramo, Colombia

Autores

Eydith Girleza Gil

Conrado Tobón

Editor

Universidad Nacional de Colombia

Descripción

Páramo ecosystems are located on the upper parts of the tropical mountains, below the snow line areas or in isolated areas where no glacier ecosystems occur. These ecosystems are considered important for their biodiversity, but mainly because they are permanent source of water for populations located at the upper and middle parts of the Andes. Recent studies indicate that ecosystems located at high altitudes, are more vulnerable to climate change and to changes in land use, which threatens the ecosystem services derived from them. There are very few studies in these ecosystems, within which, studies on the hydrological functioning are even scarcer, which seems to be related to their position in the top of the mountains and difsculties associated with the access to them. This implies that there is a need to create tools that allow us to study these ecosystems, overcoming the current difsculties. Hydrological TOPMODEL is used to investigate the hydrological functioning of the páramo of Chingaza, through a case study in La Chucua basin. For this, we calibrate and validate the model using two data sets of climate and the hydrology of the basin (climate and discharge from 2008 and 2009, respectively). Through the calibration procedure we obtain a high efsciency value of 0.76 model (coefscient Nash - Sutcliffe), which adequately represents the hydrological behavior of the páramo. Simulations with better adjustment between measured and predicted values of discharge, have low values of surface insltration excess runoff, indicating high water storage capacity on the soils. This agrees with the predominance of subsurface ƀow in studied ecosystem, given the special characteristics of soils. Results also show the large inƀuence of factors represented in the model (topography and soils), on water basin response to rainfall events. This is signiscant evidence of exceptional hydrological behavior of the páramos, mainly related to the presence of soil with high organic matter content. These results imply that TOPMODEL is a robust tool, able to represent in a precise manner the hydrological functioning of the basin La Chucua, and consequently it is expected that TOPMODEL can also represent hydrological conditions of Chingaza páramo.