RESUMO

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.

RESUMO

RESUMEN Se comparó la calidad ecológica del río Tota durante agosto 2007 y febrero 2008, y el curso alto del río Bogotá entre los meses de octubre 2013 y enero 2014, aplicando los índices BMWP/Col y ABI. Los puntos de muestreo corresponden a la parte alta, media y baja del gradiente longitudinal. En el río Tota se determinaron 27 familias correspondientes a 11 órdenes, donde las más abundantes fueron Baetidae (25,43 %), Leptohyphidae (16,43 %), Naididae (13,76 %), Chironomidae (11,42 %) y Hyalellidae (10,30 %). En el curso alto del río Bogotá se determinaron 32 familias correspondientes a 13 órdenes, y las más abundantes fueron Chironomidae (28,94 %), Leptoceridae (25,20 %), Naididae (18,34 %) y Simuliidae (8,63 %). En el río Tota, El BMWP/Col. presentó una calidad de agua buena, mientras que el ABI presentó una calidad aceptable. Por otra parte, en la parte alta del Río Bogotá, tanto el BMWP/ Col. como el ABI presentaron variaciones en la calidad del agua entre aceptable y muy crítica. El ACC para el río Tota mostró correlaciones entre la temperatura y conductividad con las familias Hyalellidae y Leptohyphidae mientras que el caudal se relaciona con Sphaeriidae; mientras que el curso alto del río Bogotá se correlacionó el caudal, la conductividad y la temperatura con la familia Veliidae. A manera de conclusión, los resultados obtenidos denotan que el índice ABI, que es un índice creado para sistemas andinos de montaña, es más sensible a los impactos que el índice BMWP/Col.

ABSTRACT The ecological quality of the Tota River was evaluated during August 2007 and February 2008 and compared to the upper part from Bogotá River between October 2013 and January 2014, by applying the BMWP/Col and ABI indexes. The sampling points corresponding to the high, medium and low part of the longitudinal gradient. In the Tota River, 27 families were determined corresponding to 11 orders, where the most abundant were Baetidae (25.43 %), Leptohyphidae (16.43 %), Naididae (13.76 %), Chironomidae (11.42 %) and Hyalellidae (10.30 %). In the upper course of Bogotá River, 32 families were determined to conform 13 orders, where the most abundant were Chironomidae (28.94 %), Leptoceridae (25.20 %), Naididae (18.34 %) and Simuliidae (8.63 %). In the river Tota, The BMWP/Col. The index showed a good status, while the ABI index exhibited an acceptable quality. On the other hand, in the upper part of the Bogotá River, both the BMWP/Col. and ABI showed variations in quality between acceptable and very critical. The CCA for the Tota River exhibited correlations between temperature and conductivity with the families Hyalellidae and Leptohyphidae while the stream flow was linked with the family Sphaeriidae. On the other hand, in the upper part of Bogotá River the stream flow, conductivity and temperature were correlated with the occurrence of the family Veliidae. Our results showed that the ABI index is more sensitive to impacts that the BMWP/Col index is showing its ability to evaluate the Andean mountain systems.