Browsing by Author "Timbe, Luis"

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Métodos para la evaluación del riesgo de inundación fluvial: revisión de literatura y propuesta metodológica para Ecuador
(Universidad de Cuenca, 2017) Pinos, Juan; Timbe, Luis; Orellana, Daniel
Floods represent one of the most frequent natural hazards globally, resulting in considerable economic and social losses in affected populations. Approaches based on risk assessment are increasingly accepted and incorporated into flood risk management in recent decades. Despite considerable progress in the development of loss estimation tools, they still present high uncertainties and disparities that often lead to questioning their quality. This work presents an in-depth and updated review of the different analytical and methodological tools incorporated in several existing models. A comparative analysis of the methodologies showed that the components and characteristics included by the different methods are highly heterogeneous and the vast majority do not incorporate an explicit validation of the model results. This comparison required a deep understanding of the structures, mechanisms and underlying assumptions of each method. Finally, the paper presents the general characteristics and the main components of a methodological proposal for the analytical evaluation of flood loss estimates for Ecuador, from the synthesis of all the evaluated methods and based on the available data.
Night irrigation reduction for water saving in medium-sized systems
(2003-04) Bievre, Bert De; Alvarado, Andrés; Timbe, Luis; Célleri, Rolando; Feyen, Jan
In many medium-sized irrigation systems water is wasted during the night because demand is low and supply is not reduced accordingly. A hydrodynamic model was applied, using MIKE 11 as a software tool, to simulate abrupt discharge changes and their travel times along small irrigation canals. Filling and emptying of the canal were also analyzed. The model was calibrated with data of a field experiment that included startup, positive, and negative surges. A technique was developed to take into account the considerable water losses in the canal. Performance indicators efficiency, adequacy, equity, and dependability, proposed by Molden and Gates in 1990, were redefined using the concept of usefully delivered discharge. The newly defined indicators were consequently used to find the gate operation scenario that meets optimally the target day and night discharges. It was found that it is feasible to implement night delivery reduction. The calibrated model was used to develop guidelines for the operation of the canal with daily flow variation, resulting in considerable water savings during the night.
Predicting climate change impacts on water resources in the tropical Andes: Effects of GCM uncertainty
(2009-04-16) Buytaert, Wouter; Célleri, Rolando; Timbe, Luis
There is a strong demand from policy makers for predictions about the potential impacts of climate change on water resources. Integrated environmental models, combining climatic and hydrologic models, are often used for this purpose. This paper examines the impact of uncertainties related to GCMs in hydrological impact studies in the tropical Andes. A conceptual hydrological model is calibrated on data from four mesoscale, mountainous catchments in south Ecuador. The model inputs are then perturbed with anomalies projected by 20 GCMs available from the IPCC Data Distribution Centre. The results show that on average, the average monthly discharge is not expected to change dramatically. However, the simulated discharges driven by different global climate model forcing data can diverge widely, with prediction ranges often surpassing current discharge.