Browsing by Author "Jerves Cobo, Rubén Fernando"

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A methodology to model environmental preferences of EPT taxa in the Machangara river basin (Ecuador)
(2017) Jerves Cobo, Rubén Fernando; Everaert, Gert; Iñiguez Vela, Xavier Patricio; Córdova Vela, Gonzalo Esteban; Díaz Granda, Catalina Monserrat; Cisneros Espinoza, Felipe Eduardo ; Nopens, Ingmar; Goethals, Peter L
Rivers have been frequently assessed based on the presence of the Ephemeroptera— Plecoptera—Trichoptera (EPT) taxa in order to determine the water quality status and develop conservation programs. This research evaluates the abiotic preferences of three families of the EPT taxa Baetidae, Leptoceridae and Perlidae in the Machangara River Basin located in the southern Andes of Ecuador. With this objective, using generalized linear models (GLMs), we analyzed the relation between the probability of occurrence of these pollution-sensitive macroinvertebrates families and physicochemical water quality conditions. The explanatory variables of the constructed GLMs differed substantially among the taxa, as did the preference range of the common predictors. In total, eight variables had a substantial influence on the outcomes of the three models. For choosing the best predictors of each studied taxa and for evaluation of the accuracy of its models, the Akaike information criterion (AIC) was used. The results indicated that the GLMs can be applied to predict either the presence or the absence of the invertebrate taxa and moreover, to clarify the relation to the environmental conditions of the stream. In this manner, these modeling tools can help to determine key variables for river restoration and protection management.
Análisis de la calidad del aire de la ciudad de Cuenca durante el año 2022 basadas en la red de microsensores a escala urbana
(Universidad de Cuenca, 2023-07-21) Chavez Loja, Kevin Paul; Jerves Cobo, Rubén Fernando
Population growth in urban areas has caused the deterioration of air quality, affecting the health of its inhabitants and the environment; consequently, the monitoring of air pollution is an important tool for its control. In this sense, the city of Cuenca - Ecuador, has implemented a monitoring network consisting of microsensors located on a neighboring scale and automatic analyzers on an urban scale. The study consisted of a descriptive and correlational analysis using the information obtained by the microsensors and automatic analyzers belonging to the Cuenca Monitoring Network during the year 2022. The analysis corresponds to air quality information from parameters such as MP10, MP2.5, CO, O3, NO2, and SO2 and from weather variables such as wind speed and wind direction. Furthermore, the observational analysis allowed to distinguish the behavior of the concentrations of indicated pollutants and their comparison with national regulations as well as with the recommendations given by the World Health Organization. The information was processed by various functions of the "Openair" package by means RStudio software, resulting in outcomes that served for the interpretation of air quality on a neighboring and urban scale. Additionally, a good correlation was determined between the values obtained by the CO and NO2 microsensors, and a good adjustment to a linear model was made for the O3 microsensor compared with values recorded from the automatic station. Finally, the present study allowed us to suggest possible emission sources and distinguish pollution patterns.
Análisis del comportamiento histerético de los parámetros de calidad del agua en zonas urbanas, periurbanas y de conservación de la subcuenca del río Machángara
(Universidad de Cuenca, 2023-07-20) Gallegos Ochoa, Milton Josue; Salinas Procel, Karen Andrea; Jerves Cobo, Rubén Fernando; Guerrero Coronel, Felix Rigoberto
The analysis of the hysteretic behavior in relation to the concentration/water level allows to identify fluctuations in the concentrations of the water quality parameters depending on the flow. The Machángara River basin is relevant because it is a source for drinking water treatment, irrigation and hydroelectric generation. The present research aims to analyze the hysteretic behavior of water quality parameters: turbidity, total solids, pH, BOD5, phosphates, nitrites-nitrates, and total coliforms, located in an urban, peri-urban and conservation area of the Machángara River sub-basin located in the Paute River basin, during the period 2006 - 2013. In this sub-basin, the influence of seasonality (dry-wet), land use, and vegetation cover on the hysteretic behavior of each of the aforementioned parameters was evaluated. For the elaboration of the hysteretic graphs, the water level was ordered chronologically along with the value of the parameter, as well as the seasonality and hysteretic direction were also represented. The results showed that the hysteretic behavior of turbidity is affected by the heterogeneity of land use and vegetation cover and the pH due to moorland vegetation and its contribution of organic material. Furthermore, seasonality influences the amplitude of the hysteretic behavior of the parameter concentrations. Finally, the study made it possible to identify that in conservation and urban areas the behavior tends to be counterclockwise, while in the peri-urban area in most parameters there is no defined hysteretic behavior.
Biological impact assessment of sewage outfalls in the urbanized area of the Cuenca river basin (Ecuador) in two different seasons
(2018) Jerves Cobo, Rubén Fernando; Lock, Koen; Van Butsel, Jana; Pauta Calle, Gladys Guillermina; Cisneros Espinoza, Felipe Eduardo; Nopens, Ingmar; Goethals, Peter L
We evaluated the biological water quality in relation to chemicals discharged through sewage outfall during both dry and rainy season. The lowland area of the Cuenca River basin in the southern Andes of Ecuador, including the city of Cuenca, constituted the study area. To perform an integrated water quality assessment, data were collected of macroinvertebrates, physicochemical conditions and morphological characteristics in 43 sites in the Cuenca River and its tributaries. The Andean Biotic Index (ABI) and the Biological Monitoring Working Party adapted to Colombia (BMWP-Col) were used to evaluate the biological water quality. Both biological indexes were higher upstream than downstream from the city. Moreover, these indexes indicated better conditions during the rainy season than in the dry season, based on the presence of more sensitive families. The biological indexes related more to the oxygen saturation than to the five-day biological oxygen demand (BOD5), nutrients and chloride concentrations. The relationship between BOD5 and nutrient concentrations with the variation of both biological indexes was clearer in the dry season than in the rainy season. However, in some sites, these indexes were influenced more by morphological aspects than by pollutants. Both biological indexes showed similar patterns along the rivers, generally the BMWP-Col scored higher than the ABI index. The latter index was shown to be more suitable for the high Andes region. These results could be used to support the implementation of river restoration actions, such as determining priorities for splitting sewer and precipitation water transport systems and needs for improved wastewater treatment facilities in specific locations. © 2018 Elsevier GmbH
Biological water quality in tropical rivers during dry and rainy seasons: a model-based analysis
(2020) Jerves Cobo, Rubén Fernando; Eurie Forio, Marie Anne; Lock, Koen; Van Butsel, Jana; Pauta Calle, Gladys Guillermina; Cisneros Espinoza, Felipe Eduardo; Nopens, Ingmar; Goethals, Peter L
Recent studies on water quality in tropical rivers indicate substantial differences between seasons. However, investigations on the needs and added value of season-specific models are lacking. Thus, this paper aims to determine the accuracy and relevance of season-specific and season-overarching models to predict biological water quality. Additionally, we investigated the variation of prediction accuracy using sub-datasets from different parts of the Cuenca River basin. This study was accomplished in the rivers that pass through the urban and suburban areas of the city of Cuenca, which is located in the southern Andes of Ecuador. The Andean Biotic Index (ABI) was used as an indicator of biological water quality. Subsequently, models were developed to predict the ABI, with physicochemical and morphological variables as predictors, which were collected in 43 sites during both the dry and the rainy seasons. The predictions were obtained using three kinds of generalized linear models (GLMs): Gaussian, Gamma and Inverse Gaussian. The season-specific models were more accurate than the season-overarching models. Similarly, the predictions of the biological water quality in sites sampled in the urban area were more accurate than the forecasts performed in reference sites. The major variables predicting the ABI during the dry season were five-day biological oxygen demand (BOD5), ammonium and orthophosphate, while dissolved oxygen (DO), oxygen saturation (OS), nitrate, total solids proved to be important during the rainy season. The results of this research emphasize the importance of developing season-specific models and the implementation of different key actions for river restoration during both the dry and rainy seasons. The accuracy and the replication of these models could be improved and checked with more data taken from new sampling events. The modelling approach developed in this study can be applied to similar basins in the tropics and reveals that environmental investments need to count on monitoring strategies and data and analyses of the biological water quality variation in dry and rainy seasons, within the context of sustainable development.
Determinación de las cargas de contaminación en aliviaderos de la red de alcantarillado combinado de la ciudad de Cuenca - Ecuador
(Universidad de Cuenca, 2020-02-28) Montalvo Cedillo, César Augusto; Jerves Cobo, Rubén Fernando
The combined sewer overflow (CSO) is one of the main causes of contamination in the receiving bodies during the rainy period. Ecuador does not have yet legislation related to the CSO processes. The objective of this research is to evaluate the behavior of three combined sewage discharges of the Tomebamba river in the city of Cuenca - Ecuador. For this, the registration of 18 CSO events has been carried out in the CSO El Vado, Multifamiliares and Coliseo. The following water quality parameters have been analyzed: conductivity, turbidity, BOD5, COD, fecal and total coliforms, nitrates, nitrites, ammoniacal nitrogen, ortho phosphate dissolved and total phosphorus. The results show that CSOs contribute to the deterioration of the water quality of the Tomebamba River during the rainy season. There is great variation in the typology of water. The Coliseo discharge does not comply with the national regulations regarding the parameters for effluent discharge in receiving water bodies. The relationship between rain and characteristics of the CSO was also analyzed through the canonical correlation analysis CCA and partial least squares regression PLSR. The result is a prediction model of pollutants based on precipitation parameters. The analysis determined that: (i) the maximum discharge rate of a CSO depends mainly on the maximum rainfall intensity (ii) the maximum rainfall intensity and average rainfall intensity, have an influence on the recorded average turbidity values (iii) The mean value of COD is related to the duration of the dry season prior to the precipitation event
Estimación del Coeficiente de Escorrentía “C” y su análisis a través de variables determinantes de la respuesta hidrológica mediante el estudio de tres cuencas urbanas de la ciudad de Cuenca-Ecuador
(Universidad de Cuenca, 2021-04-26) Rubio Ramírez, Mario Ricardo; Jerves Cobo, Rubén Fernando
The city of Cuenca faces a permanent process of urbanization, changing the hydrological response of the urbanized area, therefore, it is important to know the hydrological response of its microbasins, where the peak flow (Qp) that is produced is key in the dimensioning of hydraulic structures. Both for the analysis of hydrological response and for estimating Qp the runoff coefficient can be used, being necessary for the first part use the volumetric runoff coefficient (CVOL) and for the second the rate based runoff coefficient (CRATE), however, these values can be obtained using literature values (CTEOR). In this work the runoff coefficient (CVOL and CRATE) were estimated considering the hyetographs and hydrographs registered between March and May 2017. In addition, the coefficient was also analyzed based on the soil cover, permeable soil moisture and rainfall intensities, studying three urban micro-basins of Cuenca. The results showed that for the analyzed rainfall CRATE and CVOL were undervalued by 18% and 21% respectively against the maximum CTEOR. Moreover, it was shown that CVOL’s behavior against permeable soil moisture and impermeable soil cover shows a positive linear correlation, while the correlation with rainfall intensity is not linear. Besides a preliminary expression was found to estimate CVOL based on the soil impermeability of the urban area of Cuenca. In a future work, this relationship must be validated with more information.
Evaluación de la calidad del agua y el estado biológico de la microcuenca del Río Santa Bárbara
(Universidad de Cuenca, 2025-02-20) Coronel Sánchez, María Karla; Poma Paredes, Stefanny Pamela; Jerves Cobo, Rubén Fernando
The comprehensive water quality assessment and the biological status of a part of the Santa Bárbara River micro-basin identified the main factors affecting the sustainability of this water resource. Physical-chemical parameters such as dissolved oxygen, pH, temperature, nitrates, phosphates, and total dissolved solids were analyzed, along with microbiological parameters such as fecal coliforms. Biological parameters were evaluated using the Andean Biotic Index (ABI) and the Shannon-Wiener Diversity Index. The Water Quality Index (WQI-NSF) results classified water quality as ranging from "good" to "poor", while the ABI indicated a quality ranging from "moderate" to "poor" in areas with higher anthropogenic activity. The Shannon Index revealed a decline in biological diversity at heavily polluted places, confirming the loss of sensitive species in affected areas. Moreover, significant concentrations of heavy metals such as mercury and chromium were detected, exceeding the limits set by national regulations. These findings underscore the urgent requirement to implement comprehensive strategies for the monitoring and sustainable management of water resources in the region.
Integrated ecological modelling for evidence-based determination of water management interventions in urbanized river basins: case study in the Cuenca river basin (Ecuador)
(2020) Jerves Cobo, Rubén Fernando; Benedetti, Lorenzo; Amerlinck, Youri; Lock, Koen; De Mulder, Chaim P.; Van Butsel, Jana; Cisneros Espinoza, Felipe Eduardo; Goethals, Peter; Nopens, Ingmar
The growth of urbanization worldwide has contributed to the deterioration of the ecological status of water bodies. Efforts at improving the ecological status have been made either in isolated form or by means of integrated measures by stakeholders, but in many cases, these measures have not been evaluated to determine their benefit. In this study, we implemented a scenario analysis to restore the ecological water quality in the Cuenca River and its tributaries, which are located in the southern Andes of Ecuador. For this analysis, an integrated ecological model (IEM) was developed. The IEMlinked an urban wastewater system (IUWS) model, which gave satisfactory results in its calibration and validation processes, with ecological models. The IUWS is a mechanistic model that incorporated the river water quality model, a wastewater treatment plant (WWTP) with activated sludge technology, and discharges from the sewage system. The ecological status of the waterways was evaluated with the Andean Biotic Index (ABI), which was predicted using generalized linear models (GLMs). The GLMs were calculated with physicochemical results from the IUWS model. Four scenarios that would enhance the current ecological water quality were analyzed. In these scenarios, the inclusion of a new WWTP with carbon, and with carbon and nitrogen removal as well as the addition of retention tanks before the discharges of combined sewer overflows (CSOs) were assessed. The new WWTP with carbon and nitrogen removal would bring about a better restoration of the ecological water quality due to better nitrogen removal. The retention tanks would help to enhance the ecological status of the rivers during rainy seasons. The integrated model implemented in this study was shown to be an essential tool to support decisions in the Cuenca River basin management.
Integrated water system modelling to support water management in the Cuenca Basin
(Ghent University, 2020-01-17) Jerves Cobo, Rubén Fernando; Goethals, Peter; Nopens, Ingmar
In this chapter is evaluated the biological water quality in relation to chemicals discharged through sewage outfall during doth dry and rainy season. The lowland area of the Cuenca River basin in the southern Andes of Ecuador, including the city of Cuenca, constituted the study area. To perform an integrated water quality assessment, date were collected of macroinvertebrates, physicochemical conditions and morphological characteristics in 43 sites in the Cuenca River and its tributaries. The Andean Biotic Index (ABI) and the Biological Monitoring Working Party adapted to Colombia (BMWP-Col) were used to evaluate the biological water quality. Both biological indexes were higher upstream than downstream form the city. Moreover. These indexes indicated better conditions during the rainy season than in the dry season, based on the presence of more sensitive families. The biological indexes related more to the oxygen saturation than to the five-day biological oxygen demand (BOD5), nutrients and chloride concentrations. The relationship between BOD5 and nutrient concentrations with the variation of both biological indexes was clearer in the dry season than in the rainy season. However, in some sites, these indexes were influenced more by morphological aspects than by pollutants. Both biological indexes shoed similar patterns along the rivers, generally the BMWP-Col scored higher than the ABI index. The later index was shown to be more suitable for the high Andes region as an indicator of water quality. These results could be used to monitor the implementation of river restoration actions, such as determining priorities for splitting sewer and precipitation water transport systems and needs for improved wastewater treatment facilities in specific locations.
Model-based analysis of the potential of macroinvertebrates as indicators for microbial pathogens in rivers
(2018) Jerves Cobo, Rubén Fernando; Van Echelpoel, Wout; Cisneros Espinoza, Felipe Eduardo; Nopens, Ingmar; Goethals, Peter L
The quality of water prior to its use for drinking, farming or recreational purposes must comply with several physicochemical and microbiological standards to safeguard society and the environment. In order to satisfy these standards, expensive analyses and highly trained personnel in laboratories are required. Whereas macroinvertebrates have been used as ecological indicators to review the health of aquatic ecosystems. In this research, the relationship between microbial pathogens and macrobenthic invertebrate taxa was examined in the Machangara River located in the southern Andes of Ecuador, in which 33 sites, according to their land use, were chosen to collect physicochemical, microbiological and biological parameters. Decision tree models (DTMs) were used to generate rules that link the presence and abundance of some benthic families to microbial pathogen standards. The aforementioned DTMs provide an indirect, approximate, and quick way of checking the fulfillment of Ecuadorian regulations for water use related to microbial pathogens. The models built and optimized with the WEKA package, were evaluated based on both statistical and ecological criteria to make them as clear and simple as possible. As a result, two different and reliable models were obtained, which could be used as proxy indicators in a preliminary assessment of pollution of microbial pathogens in rivers. The DTMs can be easily applied by staffwith minimal training in the identification of the sensitive taxa selected by the models. The presence of selected macroinvertebrate taxa in conjunction with the decision trees can be used as a screening tool to evaluate sites that require additional follow up analyses to confirm whether microbial water quality standards are met. © 2018 by the authors.