Browsing by Author "Timbe Castro, Luis Manuel"

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Análisis preliminar de la vulnerabilidad del río Burgay entre el descanso y Nazón
(2008) Jaramillo Calle, Marcelo; Timbe Castro, Luis Manuel
Application of hydraulic geometry to high gradient rivers in southern Ecuador
(2021) Cisneros Espinoza, Felipe Eduardo ; Timbe Castro, Luis Manuel; Carrillo Serrano, Verónica Margarita; Petrie, Je E
Using hydraulic geometry (HG) theory, we investigated three rivers typical of the Ecuadorian mountainous region with longitudinal slopes ranging from 0.8% to 10% and coarse bed material with d50 ranging from 3 to 54 mm and values of d90 up to 908 mm. Extensive field measurements were performed to characterize geometric and hydraulic properties at 33 sites. Using these field data, at-a-station HG relationships were obtained for top width, average flow depth, and average flow velocity. Dimensional and dimensionless downstream HG relations were obtained for these parameters as well as the channel bed slope using the bankfull discharge estimated with at-a-station HG. The correlation coefficients indicate that the dimensionless equations adequately represent the observed data for all quantities with the exception of slope. In addition to a low correlation coefficient, the exponent on non-dimensional discharge was small in the downstream HG relation for slope. This small exponent indicates that slope is not dependent on discharge. Based on this finding, the non-dimensional HG relations were reformulated using both dimensionless discharge and bed slope as independent variables. These new relations show improved correlation coefficients and demonstrate the role of slope in determining channel width, flow depth, and average velocity in high gradient rivers
Applying hydrological modeling to unravel the effects of land use change on the runoff of a paramo ecosystem
(Universidad de Cuenca, 2021-09-27) Cabrera Balarezo, Juan José; Timbe Castro, Luis Manuel
El páramo es muy susceptible al cambio en el uso de la tierra y al cambio climático, y la forestación de ecosistemas de páramo con pino es una práctica común. Los efectos de las plantaciones de pinos son múltiples, incluso sobre la hidrología de la cuenca. Para conocer mejor el impacto de la forestación en la hidrología de una cuenca hidrográfica se realizó un estudio comparativo con el objetivo de obtener respuestas a las siguientes preguntas: 1) ¿Cómo calibrar los parámetros de los modelos hidrológicos sujetos a cambios de uso de la tierra? 2) ¿Cuál es el impacto sobre los picos, el caudal total y el caudal base cuando el uso de la tierra cambia gradualmente de pasto a plantaciones de pinos? y 3) ¿El impacto es diferente cuando el uso de la tierra cambia gradualmente de aguas arriba a aguas abajo (U-D) o de aguas abajo a aguas arriba (D-U)? La investigación se llevó a cabo en dos cuencas pares, respectivamente, la cuenca del Zhurucay con vegetación de pasto y la cuenca de Mpinos con plantaciones de pino. La hidrología se simuló con el software HBV-light. Además de la calibración tradicional, se utilizó la relación caudal base / caudal total como función objetivo. Este procedimiento muestra una mejora considerable en la sensibilidad del parámetro PERC, mejorando la calibración del modelo para imitar el cambio de uso de la tierra. Después de la calibración y validación, se simularon escenarios de cambio de uso de la tierra transfiriendo los valores de los parámetros calibrados. Los resultados muestran que el flujo total y el flujo base se reducen respectivamente en un 21% y un 66% y los picos se reducen en un promedio del 21%, pero individualmente pueden caer hasta el 61%. Además, encontramos que el impacto es más fuerte en los períodos secos que en los húmedos. La diferencia en el impacto entre los enfoques D-U y U-D no es contundente y debería estudiarse más. Este estudio presenta un procedimiento de calibración para cuantificar los efectos del cambio de uso de la tierra antes de que se lleve a cabo. Estas herramientas son de bajo costo y podrían usarse en muchas aplicaciones en temas como la planificación del uso de la tierra, la gestión de los recursos hídricos y la conservación del agua.
Applying hydrological modeling to unravel the effects of land use change on the runoff of a paramo ecosystem
(2022) Cabrera Balarezo, Juan José; Timbe Castro, Luis Manuel; Crespo Sánchez, Patricio Javier; Sucozhañay Calle, Adrián Esteban
To gain insights into the impact of afforestation on the hydrology of a mountain river basin, the Mpinos catchment was modeled to obtain parameters that represent pine land use. Thereafter, the parameters were applied in the Zhurucay catchment to answers the following questions: 1) How can the parameters of hydrological models subject to land use change be calibrated? 2) What is the impact on peaks, total flow, and baseflow when land use gradually changes from tussock grass to pine plantations? 3) Is the impact different when land use changes gradually from upstream to downstream (U-D) or downstream to upstream (D-U)? Based on our results, the total flow, baseflow, and peaks were reduced by 21%, 66%, and 21%, respectively. Overall, this study presents a calibration approach to predict the effects of land-use change prior to its occurrence
Assessment of microscale economic flood losses in urban and agricultural areas: case study of the Santa Bárbara River, Ecuador
(2020) Pinos Flores, Juan Andrés; Orellana Vintimilla, Daniel Augusto; Timbe Castro, Luis Manuel
To reduce and prevent significant economic flood losses, reliable tools are required to estimate potential river inundation effects. This paper focuses on the estimation of direct damages caused by flooding with different return periods in urban and agricultural areas. A univariable deterministic flood loss model was developed to estimate potential damages, based on water depth. This approach involved assessing the mapping of local flood risks based on the combination of historical inundation marks, land-use and economic data. The primary objective of this study is to determine whether it is possible to use accessible data at the municipality level to assess economic flood losses. For the Santa Bárbara River case study, the results reveal that the greatest proportion of damages (approximately 99%) is expected to occur in the urban area. In addition, results showed that the approach is useful for identifying and mapping flooded areas with critical damage. The proposed methodology can be applied to microscale analysis, thereby providing quantitative results for flood risk assessment, the outcomes of which could assist local decision-makers in the prioritization of critical risk areas, and the development of mitigation options and countermeasures. As such, this is the first study to propose and provide an open-access methodology for quantifying flood losses in the inter-Andean region of Ecuador.
Characterization of bedload sediment transport in high slope rivers using hydraulic geometry theory
(Asce library, 2019) Cisneros Espinoza, Felipe Eduardo ; Petrie, John; Pacheco Tobar, Esteban Alonso; Timbe Castro, Luis Manuel; Carrillo Serrano, Verónica Margarita
In Ecuador, steep rough-bedded channels constitute the main component of mountainous drainage system. They provide sediment to milder-slope downstream channels. Thus, sediment transport represents a driving process in natural drainage system. Namely, it defines river morphology evolution. To quantify and to understand the magnitude and effect of this process in the surrounding environment, the understanding and knowledge of bedload transport must be improved. The study of sediment transport in steeper channels with coarser material is a complex process. The continuously changing environment results in a high uncertainty in the quantification of sediment transport rates. Some equations have been proposed to quantify the rates. However the lack of actual measured data does not allow proper quantification and verification. On the other hand, hydraulic geometry (HG) theory has been applied to generate elements for a consistent monitoring of rivers behavior. Dimensionless HG relations that replicate what is observed in rivers have been obtained. Parameters such as top width, mean flow depth, mean velocity, and suspended sediment load of several gravel-bed rivers have been related with liquid discharge. The present study proposes the characterization of bedload sediment transport of steep gravel-bed rivers in terms of dimensionless HG relations. Measurements in various reaches along a river of bedload transport rate are performed to determine the parameters (exponents and coefficients) of the HG relations. The results represent a contribution that allows the reduction of the lack of field-measured data as well as the application of a theory generally used to characterize hydraulic-geometric parameters to characterize bedload sediment transport.
Desempeño de modelos hidráulicos 1D y 2D para la simulación de inundaciones Lus Timbe
(Universidad de Cuenca, 2011-07) Timbe Castro, Luis Manuel; Willems, Patrick; DIUC; Universidad de Cuenca; Dirección de Investigación de la Universidad de Cuenca
Nowadays, the availability of high resolution Digital Elevation Models (DEMs) to represent the earth surface allows coupling of hydraulic models with Geographic Information Systems (GIS) to obtain the flood extent and water levels in floodplains. Many studies on flood mapping have been conducted using one or two dimensional (1D/2D) hydrodynamic models. Some authors affirm that 2D hydraulic models are the state of the art for river flood modeling. They have, however, the disadvantage that their application is constrained by the high requirements for data, hardware and software. 1D models are capable of modeling precisely the flow in main rivers, but are less accurate for modeling over bank flow. The aim of the investigation is to test the accuracy for river floodplain modeling comparing a quasi-2D approach using a 1D model with a full 2D approach. The models were tested for the river Dender in Belgium for three historical flood events.
Differences Between Effective and Physical Roughness Parameter- A Headwater Mountain River Experiment
(IEEE, 2021) Cedillo Galarza, Juan Sebastian; Alvarado Martínez, Andrés Omar; Narea Cardenas, Katherine Estefania; Sánchez Cordero, Esteban Remigio; Timbe Castro, Luis Manuel; Samaniego Alvarado, Esteban Patricio
One-dimensional hydrodynamic models (HM) are widely used in the hydraulic modeling of rivers and channels. The result obtained with this type of model depends largely on correct estimation the roughness parameter. The value of the roughness parameter obtained through a HM calibration process differs from the one measured in the field. Hence, the objective of this research is focused on identifying the difference between physical and effective roughness for different morphologies present in Mountain Rivers. Physical roughness was indirectly measured with field data and Manning equation, while Effective roughness was found through GLUE experiments using water depth as validation data in one dimensional models in HEC RAS. Physical and effective roughness coefficients have shown differences depending on the morphology. In Cascade and Step-pool the physical roughness is higher than effective roughness, while in Plane-bed effective roughness is higher than physical roughness. The differences are attributed to the deviations that occur between the real conditions and the flow idealizations in an 1D - HD model. For any modelling application is important to research roughness values used previously and avoid formulations or tables which are based on field measurements.
Estudio de prefactibilidad del sistema de riego Atuhuaico en la provincia del Cañar
(1993) Calle Quesada, Pablo; Romero Cabrera, Lenin; Timbe Castro, Luis Manuel; Cordero Ortiz, Patricio
Evaluación del modelo HEC-HMS para la simulación hidrológica de una cuenca de páramo
(2017) Cabrera Balarezo, Juan José; Timbe Castro, Luis Manuel
This study evaluated the performance of the semi-distributed model HEC-HMS, for the simulation of rain-runoff processes in a paramo basin. This analysis was carried out in the upper part of the Quinuas River basin (southern Ecuador) located within El Cajas National Park (2 ° 47`S, 79 ° 11`O) with an approximate area of 21.8 km2 and an altitudinal gradient between 3612 and 4400 m asl. The calibration and validation was performed for a period of 3 years from july-2013 to june-2016. The Soil Moisture Accounting (SMA) module was used as the main method. For the rainfall distribution, the Thiessen polygons were used, while the evapotranspiration was calculated with the Penman-Monteith method. The results reveal that (1) 83% of the water infiltrates the soil while only 17% is retained in plants and the soil surface, (2) the water is retained for approximately 42 days before getting to the river and (3) that more than 60% of the flow corresponds to sub-surface flow.
Evaluation of 1D hydraulic models for the simulation of mountain fluvial floods: a case study of the Santa Bárbara river in Ecuador
(2019) Pinos Flores, Juan Andres; Timbe Castro, Edison Patricio; Timbe Castro, Luis Manuel
River flooding is a key topic for water managers because of social and economic losses it can cause. The complex topography and dynamics of mountain rivers has limited the analysis of their behavior during flood events (e.g., sediment transport, flooding). This study aims to test the performance of three hydraulic 1D models (HEC-RAS, MIKE 11, and Flood Modeller) to estimate inundation water levels for a mountain river. The evaluation of these models was performed considering steady state conditions through 10 scenarios, i.e. five discharge return periods, and two types of cross sections data (a) type I, a detailed field survey complemented with information extracted from DEM, derived from LiDAR; and (b) type II, cross sections exclusively derived from the DEM. The research was conducted for a reach of 5 km of the Santa Bárbara River, with an average slope of 0.25%. HHEC-RAS model results for cross sections type I, were previously validated and therefore used as reference for comparison between other models and scenarios. The goodness-of-fit between models was measured based on the Nash-Sutcliffe model efficiency coefficient (EF). The main goal of the current study was to determine the variability of inundation level results compared with a validated model as reference, using the same input data for the three modeling packages. Our analysis shows that, when using cross section type I, the evaluated modeling packages yield similar results (EF were between 0.94 and 0.99). On the other hand, the goodness of fit decreased when using type II data, with an average EF of 0.98 (HEC-RAS), 0.88 (Flood Modeller) and 0.85 (MIKE 11) when compared to the reference model. The authors conclude that it is highly recommend for practitioners to use geometric data type I instead of type II in order to obtain similar performance in the tested models. Only HEC-RAS type II has the same performance as type I models (average EF of 0.98).
Evaluation of the HEC-HMS model for the hydrological simulation of a paramo basin
(2019) Cabrera Balarezo, Juan José; Timbe Castro, Luis Manuel; Crespo Sánchez, Patricio Javier
In this study, the performance of the HEC-HMS model was evaluated for the simulation of rain-runoff processes in a paramo basin of approximately 21. 8 km2, south of Ecuador. The calibration and validation comprises the period of July-2013 to June-2016 with daily data. The Soil Moisture Accounting (SMA) method was used to compute the water flow in the soil. For the rainfall distribution, the Thiessen method was used, while the Evapotranspiration was calculated with the Penman-Monteith equation. The results revealed that (1) 83% of the water infiltrates the soil while only 17% is retained in plants and the soil surface, (2) the water is retained for approximately 42 days before reaching the river and (3) that more than 60% of the flow corresponds to sub-surface flow.
Impact of the conservation mechanism to supply water to community drinking water systems and irrigation systems in rural Andean regions and its relationship with the Sustainable Development Goals
(Universidad de Cuenca, 2025-04-07) Carvajal Arizábala, Johanna Gabriela; Sucozhañay Calle, Adrián Esteban; Célleri Alvear, Rolando Enrique; Timbe Castro, Luis Manuel
The conservation of ecosystems is key to ensuring the availability of natural resources like water, a critical service for sustaining human activities. However, the impact of conservation on human well-being remains uncertain. This study explores the links between water provision, local activities, and Sustainable Development Goals (SDGs), focusing on the rural Andean community of El Carmen de Jadán, Azuay, Ecuador. This community, located downstream of the Aguarongo Protected Forest (APF), depends on water from headwaters for agriculture, livestock, and daily needs. Conservation efforts since the 1990s have helped secure this resource. We developed a storyline to build a conceptual framework integrating water provision, respondents’ activities, and personal and community goals. Then, we surveyed 55 water users and analyzed the results using two indices: Level of Support for Contribution (LSC) and Importance of Contribution (IC). A network analysis of high LSC and IC values revealed co-occurrences among components. Results show that the activities most linked to water are human consumption (44–52 responses), followed by livestock (29–37), agriculture (24–29), and ancestral health practices (28). Human consumption was related to SDG targets 2.4, 6.1, 6.4, 6.6, 12.8, 13.3, 15.2, and 15.4 (346–416 connections). Agriculture, livestock, and ancestral health practices were linked to all targets analyzed, including 1.1, 1.2, 2.1, and 2.4 (253–308, 220–427, and 286 connections). These findings underscore the connection between ecosystem conservation, livelihoods, and global goals. Strategies such as irrigation optimization, water monitoring, and community participation can enhance water management and promote local well-being.
Mapeo del peligro de inundación en ríos de montaña, caso de estudio del río Burgay
(2012) Timbe Castro, Luis Manuel; Timbe Castro, Edison Patricio
HEC-RAS, an one-dimensional hydraulic model, was used to simulate and map floods along a 10 km stretch of the Burgay river. Analysis of the results reveals that the model is capable of simulating the flood and inundation situation along rivers in the Andean region, notwithstanding scarcity of information. Local governments (e.g. municipalities) can use the flood hazard zoning maps for the sustainable management of alluvial plains, through the planning and implementation of structural or non-structural measures (e.g. land use planning) considering the physical conditions of the riverbanks.
Métodos para la evaluación del riesgo de inundación fluvial: revisión de literatura y propuesta metodológica para Ecuador
(2017) Pinos Flores, Juan Andres; Timbe Castro, Luis Manuel; Orellana Vintimilla, Daniel Augusto
Las inundaciones representan uno de los peligros naturales más frecuentes a nivel global, ocasionando considerables pérdidas económicas y sociales en las poblaciones afectadas. En las últimas décadas, las propuestas basadas en la evaluación del riesgo son cada vez más aceptadas e incorporadas en la gestión del riesgo de inundaciones. A pesar del progreso considerable en el desarrollo de herramientas de estimación de pérdidas, éstas aún presentan incertidumbres altas y disparidades que a menudo llevan a cuestionar su calidad. Este trabajo presenta una revisión exhaustiva y actualizada de las diferentes herramientas analíticas y metodológicas incorporadas en varios modelos existentes. El análisis comparativo de las metodologías mostró que los componentes y características incluidas por los diferentes métodos son altamente heterogéneos y la gran mayoría no incorporan una validación explícita de los resultados del modelo. Esta comparación requirió de una profunda comprensión de las estructuras, mecanismos y supuestos subyacentes de cada método. Finalmente, el artículo presenta las características generales y los principales componentes de una propuesta metodológica para la evaluación analítica de estimación de pérdidas por inundación para el Ecuador, a partir de la síntesis de todos los métodos evaluados y en función de la información disponible.
Multicriteria assessment of water dynamics reveals subcatchment variability in a seemingly homogeneous tropical cloud forest catchment
(2017) Timbe Castro, Edison Patricio; Feyen, Jan; Timbe Castro, Luis Manuel; Crespo Sánchez, Patricio Javier; Célleri Alvear, Rolando Enrique; Windhorst, David; Frede, Hans Georg; Breuer, Lutz
To improve the current knowledge of the rainfall–runoff phenomena of tropical montane catchments, we explored the usefulness of several hydrological indicators on a nested cloud forest catchment (76.9 km2). The used metrics belong to 5 categories: baseflow mean transit time, physicochemical properties of stream water, land cover, topographic, and hydrometric parameters. We applied diverse statistical techniques for data analysis and to contrast findings. Multiple regression analysis showed that mean transit times of base flow could be efficiently predicted by sodium concentrations (higher during baseflows) and temperatures of stream water, indicating a major influence of geomorphology rather than topographic or land cover characteristics. Principal component analysis revealed that no specific subset of catchment indicators could be identified as prevailing descriptors for all catchments. The agglomerative hierarchical clustering analysis provided concomitant results, implying larger levels of dissimilarity between smaller subcatchments than between larger ones. Overall, results point out an intricate interdependence of diverse processes at surface and subsurface level indicating a high level of heterogeneity. Disregarding heterogeneity of nested or paired catchments could lead to incomplete or misleading conclusions, especially in tropical mountain regions where pronounced spatial and temporal gradients are present.
On the effect of the refinement of the roughness description in a 2D approach for a mountain river: A case study
(2021) Alvarado Martínez, Andrés Omar; Timbe Castro, Luis Manuel; Samaniego Alvarado, Esteban Patricio
The prediction of water levels in rivers is important to prevent economical as well as human losses caused by flooding. Hydraulic models are commonly used to predict those water levels and take actions to mitigate flooding damage. In this research, a 2D approach to solve the depth average Reynolds Average Navier Stokes (RANS) equations, called Conveyance Estimation System (CES), is analyzed to explore its capabilities for prediction. This article presents an extension of the study performed in Knight et al. (2009). More specifically, in this study, a more detailed characterization of the roughness parameter and the number of roughness zones is explored producing additional scenarios. The performance of each scenario is evaluated by means of different fitting functions using rating curves for comparison. The research shows that the use of an adequate roughness description, such as a roughness factor calibrated for the whole cross section or a boulder roughness model calibrated for the channel bed plus roughness values from the CES roughness advisor for banks, leads to optimal model results in a mountain river.
Patterns of difference between physical and 1-D calibrated effective roughness parameters in mountain rivers
(2021) Timbe Castro, Luis Manuel; Alvarado Martínez, Andrés Omar; Samaniego Alvarado, Esteban Patricio; Cedillo Galarza, Juan Sebastián; Sánchez Cordero, Esteban Remigio
Due to the presence of boulders and different morphologies, mountain rivers contain various resistance sources. To correctly simulate river flow using 1-D hydrodynamic models, an accurate estimation of the flow resistance is required. In this article, a comparison between the physical roughness parameter (PRP) and effective roughness coefficient (ERC) is presented for three of the most typical morphological configurations in mountain rivers: cascade, step-pool, and plane-bed. The PRP and its variation were obtained through multiple measurements of field variables and an uncertainty analysis, while the ERC range was derived with a GLUE procedure implemented in HEC-RAS, a 1-D hydrodynamic model. In the GLUE experiments, two modes of the Representative Friction Slope Method (RFSM) between two cross-sections were tested, including the variation in the roughness parameter. The results revealed that the RFSM effect was limited to low flows in cascade and step-pool. Moreover, when HEC-RAS selected the RSFM, only acceptable results were presented for plane-bed. The difference between ERC and PRP depended on the flow magnitude and the morphology, and as shown in this study, when the flow increased, the ERC and PRP ranges approached each other and even overlapped in cascade and step-pool. This research aimed to improve the roughness value selection process in a 1-D model given the importance of this parameter in the predictability of the results. In addition, a comparison was presented between the results obtained with the numerical model and the values calculated with the field measurements.
Performance assessment of two-dimensional hydraulic models for generation of flood inundation maps in mountain river basins
(2019) Timbe Castro, Luis Manuel
Abstract Hydraulic models for the generation of flood inundation maps are not commonly applied in mountain river basins because of the difficulty in modeling the hydraulic behavior and the complex topography. This paper presents a comparative analysis of the performance of four two-dimensional hydraulic models (HEC-RAS 2D, Iber 2D, Flood Modeller 2D, and PCSWMM 2D) with respect to the generation of flood inundation maps. The study area covers a 5-km reach of the Santa Barbara River located in the Ecuadorian Andes, at 2330 masl, in Gualaceo. The model's performance was evaluated based on the water surface elevation and flood extent, in terms of the mean absolute difference and measure of fit. The analysis revealed that, for a given case, Iber 2D has the best performance in simulating the water level and inundation for flood events with 20- and 50-year return periods, respectively, followed by Flood Modeller 2D, HEC-RAS 2D, and PCSWMM 2D in terms of their performance. Grid resolution, the way in which hydraulic structures are mimicked, the model code, and the default value of the parameters are considered the main sources of prediction uncertainty.
Physics-Informed Neural Network water surface predictability for 1D steady-state open channel cases with different flow types and complex bed profile shapes
(2022) Alvarado Martínez, Andrés Omar; Cedillo Galarza, Juan Sebastian; Núñez, Ana Gabriela; Sánchez Cordero, Esteban Remigio; Timbe Castro, Luis Manuel; Samaniego Alvarado, Esteban Patricio
The behavior of many physical systems is described by means of differential equations. These equations are usually derived from balance principles and certain modelling assumptions. For realistic situations, the solution of the associated initial boundary value problems requires the use of some discretization technique, such as finite differences or finite volumes. This research tackles the numerical solution of a 1D differential equation to predict water surface profiles in a river, as well as to estimate the so-called roughness parameter. A very important concern when solving this differential equation is the ability of the numerical model to capture different flow regimes, given that hydraulic jumps are likely to be observed. To approximate the solution, Physics-Informed Neural Networks (PINN) are used. Benchmark cases with different bed profile shapes, which induce different flows types (supercritical, subcritical, and mixed) are tested first. Then a real mountain river morphology, the so-called Step-pool, is studied. PINN models were implemented in Tensor Flow using two neural networks. Different numbers of layers and neurons per hidden layer, as well as different activation functions (AF), were tried. The best performing model for each AF (according to the loss function) was compared with the solution of a standard finite difference discretization of the steady-state 1D model (HEC-RAS model). PINN models show good predictability of water surface profiles for slowly varying flow cases. For a rapid varying flow, the location and length of the hydraulic jump is captured, but it is not identical to the HEC-RAS model. The predictability of the tumbling flow in the Step-pool was good. In addition, the solution of the estimation of the roughness parameter (which is an inverse problem) using PINN shows the potential of this methodology to calibrate this parameter with limited cross-sectional data. PINN has shown potential for its application in open channel studies with complex bed profiles and different flow types, having in mind, however, that emphasis must be given to architecture selection.