Spatio-temporal analysis of the hydrological response to land cover changes in the sub-basin of the Chicú river, Colombia.

During the last years, in the sub-basin of the Chicú river, the agricultural and cattle exploitation has intensified and has depleted the water resources, thereby causing a deficit that has limited the continuity of such agricultural activity. Therefore, it is necessary to quantify land use and land cover changes contribute to the hydrological response to achieve sustainable management of the water resources in the sub-basin. In this sense, an integrated approach was used, which includes the SWAT (Soil and Water Assessment Tool) hydrological model and the different LUCC (Land use and cover change) maps obtained through tele-detection by using Landsat images to decide the hydrological response in the basin with the changes in land cover and uses in 1997, 2001, 2006, 2011, and 2016. As a result of the SWAT modeling, it can be noticed that the surface run-off varies according to the type of cover and extension, increasing or decreasing the water flow according to the characteristics of each cover, as in the case of bare lands (AGRL). While in 2006 it represented an area of 7.32% with a run-off of 39.25 mm, in 2001 its area decreased to 5.66% with a run-off of 44.9 mm. Moreover, in 1997 a flow of 4.45 m 3 / s can be observed, whereas in 2001 it decreases by 15% in the main current, which can be justified by a decrease of 8.8% in dense (FRSD) and fragmented (FRDT) forests. For 2006 and 2011 scenarios, the flow increases 13% and 50%, respectively, which corresponds to an increase of 36% and 48% concerning 2001 in clean grasses (PAST); despite the increase in clean grasses (PAST), the surface run-off was maintained almost constant above 9 mm, and it is thus considered a more stable vegetation cover.