University of Twente Student Theses


Contrasting two catchments with hydrological modelling in the Guatiquia river basin, Paramo Chingaza, Colombia

Jaramillo, Roberto (2011) Contrasting two catchments with hydrological modelling in the Guatiquia river basin, Paramo Chingaza, Colombia.

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Abstract:The water cycle in the Andes mountains is poorly understood due to lack of research and reliable data series. Understanding the role of a land cover or an ecosystem in local and regional rainfall runoff relations is just required to take decisions over a catchment, as extreme climatic conditions and changing landscapes, pose a threat on water supply. For watershed management, in this case water supply, it is valuable to have answers or approaches based on research. In order to have a better understanding of the local hydrological cycle and its relation with the land cover, a hydrological analysis was done. A quality analysis was performed on the data acquired from different initiatives and remote sensing and GIS is used to investigate the landscape and land cover. A land cover change was assessed since 1977 with Landsat images. Finally it is a successful application of the Topmodel (Beven & Kirby 1979) to simulate run-off for alpine and forested catchments in the tropical Andes region. Even though the simulations are not able to reproduce the complete observed behaviour of the run-off for the systems studied, it satisfactorily explains the behaviour for some parts of the hydrograph. Correlation coefficients result in values as high as 0.87 for the Paramo catchment and 0.71 for the forested one. The errors present in the discharge measurements, as well as the fact that not all the precipitation events could be described, in addition to the propagation of incorrect rainfall measurement in overall precipitation for the catchment into the simulations, limit the correlation results. Sensitivity analysis of the simulations to changes in the parameters that control; recession, soil depth, transmissivity and root zone’s effective depth, was done showing their importance and effect on the simulations. A calibration & validation exercise was done on split data sets. Finally the simulations for the two catchments were compared. The fitted parameters lie in a close range, being both systems at the moment explained with similar parameter values, coinciding with their characteristics; shallow soils and low hydraulic conductivity. The ground meteorological data contained gaps. Using simple procedures the data series were completed and estimated daily rainfall from point measurements to the total precipitation over the studied systems. There was no general clear trend in precipitation records, while the 15 year temperature series show a considerable increasing trend. The study area showed no significant land cover change, consequence of an effective management of protected areas and the adaptation of management by local communities. The temporal resolution & data quality is limiting the answers of this research. It is necessary for research to continue in this line, with finer temporal resolution and more instrumentation for local and regional watershed assessment.
Item Type:Essay (Master)
Faculty:ITC: Faculty of Geo-information Science and Earth Observation
Programme:Geoinformation Science and Earth Observation MSc (75014)
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