Volumen 2 No. 1 (2011)
Permanent URI for this collectionhttps://dspace-test.ucuenca.edu.ec/handle/123456789/5374
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Item 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 CuencaNowadays, 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.Item Identifcation of the runoff generation processes in a montane cloud forest combining hydrometric data and mixing model analysis(Universidad de Cuenca, 2011-07) Crespo Sánchez, Patricio Javier; Bücker, Amelie; Feyen, Jan; Vache, Kellie B.; Frede, Hans Georg; Universidad de Cuenca; Dirección de Investigación de la Universidad de Cuenca; Breuer, LutzField observations of runoff generation in pristine montane cloud forests are scarce. However, this knowledge is important for a sustainable natural resources management. Here we report results of a study carried out in the San Francisco River basin (75,3 km2) located on the Amazonian side of the Cordillera Real in the southernmost Andes of Ecuador. The basin is mainly covered with cloud forest, sub-páramo, pasture and ferns. A nested sampling approach was used for the collection of stream water samples and discharge measurements in the main tributaries and outlet of the basin. Additionally, soil and rock water samples were collected. Weekly to biweekly water grab samples were taken at all stations in the period April 2007 to November 2008. Hydrometric, mean residence time and mixing model approaches allowed identifying the main hydrological processes that control the runoff generation in the basin. Results clearly reveal that flow during dry conditions mainly consists of lateral flow through the C-horizon and cracks in the top weathered bedrock layer. The data shows that all catchments have an important contribution of this deep water to runoff, no matter whether pristine or deforested. During normal to low precipitation intensities, when antecedent soil moisture conditions favor water infiltration, vertical flow paths to deeper soil horizons with subsequent lateral sub-surface flow contributes most to streamflow. Under wet conditions in forested catchments streamflow is controlled by near-surface lateral flow through the organic horizon, and it is unlikely that Horton overland flow occurs during storm events. By absence of the litter layer in pasture streamflow under wet conditions primarily originates from the rooted surface layers and the A horizon, and Hortonian overland flow during extreme events.Item Characterizatión of main external climate influences in rainfall and air temperature in the Paute River Basin - Southern Andes of Ecuador(Universidad de Cuenca, 2011-07) Mora, D. E.; Willems, Patrick; DIUC; Universidad de Cuenca; Dirección de Investigación de la Universidad de CuencaCharacterization of climate variability in the Andes mountain range needs special assessment as rainfall and temperature are extremely variable in space and time. This paper examines the anomalies of observed month rainfall and temperature data of respectively 25 and 16 stations, from the early 1960‟s to the 1990‟s and compare them against anomalies from different external climate influences in annual and 3-month seasonal block periods. The stations are located in the Río Paute Basin in the Ecuador‟s southern Andes. All stations are within the elevation band 1800 and 4200 m a.s.l. and affected by the Tropical Pacific, Amazon and Tropical Atlantic climate. The results show similar temperature variations for the entire region, which are highly influenced by the ENSO, especially during the DJF season. During JJA, the correlation is weaker showing the influence of other climate factors. Higher temperature anomalies are found at the high elevation sites while in deep valleys the anomalies are less significant. Rainfall variations depend, in addition to elevation, on additional factors such as the aspect orientation, slope and hydrological regime. Highest and most significant rainfall anomalies are found in the eastern sites.Item Hydraulic assessment of waste stabilization ponds: comparison of computational fluid dynamics simulations against tracer data(Universidad de Cuenca, 2011-07) Alvarado, Andrés; Vedantam, Sreepriya; Durazno, Galo; Nopens, Ingmar; DIUC; Universidad de Cuenca; Dirección de Investigación de la Universidad de CuencaThe overall performance of a wastewater treatment plant is in addition to the effectiveness of the biokinetic processes controlled by the flow dynamics. A wide used technique to characterize the water flow dynamics is the use of tracers. At full-scale tracer experiments in wastewater treatment plants provide insufficient information to completely grasp the flow dynamics. Additionally results are often biased by uncontrolled external factors. As alternative, computational fluid dynamic (CFD) models for performance analysis of existing and the design of new wastewater treatment plants have been increasingly used over the last decade. The paper presents the results of a tracer experiment against the output of a CFD model with application to a 7 ha large maturation pond. The tracer study was conducted with the fluorescence dye Rhodamine WT using the stimulus response technique. The three dimensional CFD model was built considering a variable density distribution of spatial grids based on the specific characteristics of the system. For the unsteady flow simulations the turbulence model k- was adopted. Residence time distribution (RTD) generated by both approaches were compared and showed fairly good agreement. The velocity and turbulence profiles of the CFD model were compared with experimental data confirming, although the high computational demand, the robustness of the used CFD model.Item On the assesment of water resources model predictions(Universidad de Cuenca, 2011-07) Vázquez Zambrano, Raúl Fernando; DIUC; Universidad de Cuenca; Dirección de Investigación de la Universidad de CuencaThe analysis of the most commonly used measures of hydrological/hydraulic model performance was herein carried out by means of their statistical examination and illustrative modelling applications. In doing so, the model performance indexes were classified in two groups, according to the type of error (or residual) that those indexes are measuring: (i) statistics measuring the average systematic error (model bias); and (ii) statistics measuring the average combined systematic and random discrepancies among simulations and observations. The reader can in this way easily select a set of unrelated statistics to report on model performance. The manuscript addresses as well the main pitfalls of some of the most popular statistics used in scientific literature and suggests some approaches to overcome such potential pitfalls when addressing model performance.Item Metales pesados en humedades de arroz en la Cuenca baja del Río Guayas(Universidad de Cuenca, 2011-07) Pozo, Wilson; Santafeliu, Teófile; Carrera, Gloria; DIUC; Universidad de Cuenca; Dirección de Investigación de la Universidad de CuencaIn the lower basin of Guayas, more in particular in the wetland area, the rice is cultivated on 350.000 ha. An area of 100 km2, covering both sides of the tributary river Babahoyo, situated in the cantons Samborondón and Yaguachi, was selected to study the presence of heavy metals in the top soil and plants. Soil samples were collected in 26 sites, whereas plants were sampled in 5 sampling stations. The concentration of heavy metals in the top soil was related to soil edaphological properties and the concentration in the rice plants, using multivariate analysis. At each site 12 variables were measured resulting over the 26 sites in the following average values: MO 4%, clay 32,7%, loam 49,8%, sand 17,5%, pH 6,6, CE 7,9 mS m-1, metal concentration in mg kg-1 Cu 48,8, Fe 8.734, Mn 343, Zn 34, Hg not detected, Cd 0,15 y Pb 4,4. Statistical analysis revealed that 40,7% of the spatial variability in heavy metals in the top soil is explained by the first two principal components, loam and clay (CP1) and clay and cadmium (CP2). In addition, the 26 sites could be grouped in 6 distinct classes at an euclidian distance of 3,22. Based on the concentration the heavy metals in the top soil rank from high to low as follows: Fe > Mn > Cu > Zn > Pb > Cd and Hg not detected. The concentration of lead in the sites where also the lead concentration was measured in the rice plants, 5 locations in total, rangedItem Actitudes de los adolescentes escolarizados de Cuenca hacia la diversidad sexual(Universidad de Cuenca, 2011-07) Pinos Vélez, Verónica Patricia; Pinos Abad, Guido MarceloThe overall objective of the survey was to assess the attitude of school age adoloscents regarding LGBT (Lesbians, Gays, Bisexuals and Transsexuals) and the factors controlling the attitude. Knowledge of the extent and insight in the controlling factors will help in providing efficient and effective educational programs ensuring equality and respect regarding this minority group. The research was quantitative, transversal, descriptive and comparative. A survey was applied to 1130 high school students and 31 teachers to investigate the relationship between the attitudes regarding the LGBT minority group and the socio-demographic, family, community and personal factors of the sampled population. For the exploration of the relationship between the variables use was made of the chi-square statistics. Analysis of the survey data revealed that the majority of the adolescents had liberal homophobia attitudes. The factors controlling this attitude by school age adolescents regarding LGBT are: high school type, age, gender, level of religiosity, education level of parents, level of family communication, degree of prejudiced believes, to know a person who is LGBT, and sexual orientation. In summary, the adolescents from Cuenca have homophobic attitudes, which justifies the development of educational programs with the challenging objective of changing the attitudes towards LGBT.