Medición de la concentración de sedimentos en suspensión mediante dispositivos ópticos y acústicos: aplicación en sistemas tropicales (Delta del río Mira, Colombia)

En los últimos años, la utilización de dispositivos ópticos (e.g. Optical Backscatter Sensor, OBS) y acústicos (e.g. Acoustic Doppler Current Profiler-ADCP) ha permitido monitorear con mayor resolución la variabilidad temporal y espacial de la concentración de sedimentos en suspensión (CSS) en ambientes costeros y estuarinos. Sin embargo, la aplicación de estas técnicas en ambientes tropicales ha tenido un desarrollo incipiente. En el presente trabajo se implementó un procedimiento de calibración para un dispositivo OBS-3A, tomando como patrón de calibración sedimento seco y desagregado de la zona de estudio. Además, se presentan las correcciones a las que se debe someter la señal de respuesta del ADCP, debido a la dispersión geométrica, la atenuación del sonido por el agua y las partículas en suspensión, para que sea útil en la estimación de CSS. El ADCP y el OBS-3A se utilizaron para realizar mediciones de CSS en el sistema deltaico del río Mira (isla del Morro y desembocadura principal), ubicado sobre la costa del Pacífico colombiano, un ambiente costero tropical donde algunos factores oceanográficos y estuarinos son determinantes en la señal de respuesta de los equipos.In recent years, the use of optical (Optical Backscatter Sensor, OBS) and acoustic (Acoustic Current Doppler Profiler, ADCP) instruments has allowed monitoring the temporal and spatial variation of the suspended sediment concentration (SSC) in coastal and estuarine environments with greater resolution. However, the development of the application of those techniques in tropical environments is incipient. For this study, an OBS-3A calibration procedure was implemented, taking dry and desegregated sediment from the study zone as a calibrating pattern. Moreover, we present the corrections required for the ADCP signal to be useful in the estimation of SSC due to geometrical spreading, the attenuation of sound by water, and the particles in suspension. The ADCP and OBS-3A were used to measure SSC in the Mira River delta system (Morro Island and principal river mouth), located on the Pacific coast of Colombia, a coastal tropical environment where some oceanographic and estuarine factors determine the signal response of the instruments

Predicción de caudales en río Colorado, Argentina

The identification of suitable models for predicting daily water flow is important for planning and management of water storage in reservoirs of Argentina. Long-term prediction of water flow is crucial for regulating reservoirs and hydroelectric plants, for assessing environmental protection and sustainable development, for guaranteeing correct operation of public water supply in cities like Catriel, 25 de Mayo, Colorado River and potentially also Bahía Blanca. In this paper, we analyze in Buta Ranquil flow time series upstream reservoir and hydroelectric plant in order to model and predict daily fluctuations. We compare results obtained by using a three-layer artificial neural network (ANN), and an autoregressive (AR) model, using 18 years of data, of which the last 3 years are used for model validation by means of the root mean square error (RMSE), and measure of certainty (Skill). Our results point out to the better performance to predict daily water flow or refill them of the ANN model performance respect to the AR model. La identificación de modelos adecuados para predecir caudales diarios es importante para la planificación y la gestión de almacenamiento de agua en los embalses de la Argentina. La predicción a largo plazo del caudal es crucial para la regulación de los embalses y centrales hidroeléctricas, evaluar la protección del medio ambiente y el desarrollo sostenible, garantizar el correcto funcionamiento del abastecimiento público de agua en ciudades como Catriel, 25 de Mayo, río Colorado y también, eventualmente, en Bahía Blanca. En este trabajo, se analizan series de tiempo de caudales de agua, arriba del embalse y de la planta hidroeléctrica en Buta Ranquil, para modelar y predecir las fluctuaciones diarias. Se comparan los resultados obtenidos mediante el uso de una red neuronal artificial (ANN) de tres capas y un modelo autoregresivo (AR), con 18 años de datos, cuyos últimos 3 años se utilizan para la validación del modelo por medio de la raíz del error cuadrado medio (RMSE) y medida de certeza (Skill). Para predecir o rellenar el caudal diario, los resultados indican que el mejor desempeño es del ANN con respecto al modelo AR.Fil: Pierini, Jorge Omar. Universidad Nacional del Sur; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Gomez, Eduardo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Tecnologica Nacional; ArgentinaFil: Telesca, Luciano. Istituto di Metodologie per l’Analisi Ambientale; Itali

Investigating Prediction Performance of an Artificial Neural Network and a Numerical Model of the Tidal Signal at Puerto Belgrano, Bahia Blanca Estuary (Argentina)

In the present study we compare performances of the prediction of hourly tidal level variations at Puerto Belgrano, a coastal site in the Bahia Blanca Estuary (Argentina), by means of the MOHID model, which is a numerical model designed for coastal and estuarine shallow water applications, and of an artificial neural network (ANN). It was shown that the ANN model is able to predict the hourly tidal levels over long term duration with at least seven days of observations and with a better performance in respect to the numerical model. Our findings can be useful to implement ANN-based tools for future studies of the hydrodynamics of Bahía Blanca estuary.Fil: Pierini, Jorge Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto Argentino de Oceanografía (i); ArgentinaFil: Lovallo, Michele. Agenzia Regionale per la Protezione dell’Ambiente; ItaliaFil: Telesca, Luciano. National Research Council, Institute of Methodologies for Environmental Analysis; ItaliaFil: Gomez, Eduardo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto Argentino de Oceanografía (i); Argentin

The application of MOHID to assess the potential effect of sewage discharge system at Bahía Blanca estuary (Argentina)

The Bahıa Blanca urban wastewater treatment plant (UWWTP) discharges the wastewater from the city into the Bah´ıa Blanca Estuary through a tidal channel located 4 km south from the closest city, Ingeniero White, and 1.7 km south from the mouth of the Napost´a Creek. There are four UWWTPs discharging in the Bah´ıa Blanca Estuary, with the highest flow from the Bah´ıa Blanca UWWTP at 65000 m3 d−1, corresponding to 77% of the total (Heffner et al. 2003). Wastewater is an important source of freshwater in the Bah´ıa Blanca estuary comprising 23.3% of the overall freshwater, with contributions of a similar magnitude as the freshwater inputs from the Napost´a Grande Creek, 86400 m3 d−1 (Carrica 1998) and the Sauce Chico creek, 164000 m3 d−1. Sewerage systems in Bah´ıa Blanca city are designed with overflow structures that discharge into local waterways when the capacity of the system is exceeded. Overflows occur when the hydraulic capacity of the system is exceeded due to heavy rains. During dry periods, overflow can also take place due to blockages or pump failures. Aguas Bonaerenses Sociedad An´onima (ABSA) manages the main network. The aim of this research was to analyze the potential risks of sewage in the estuary and the installation of a new UWWTP on the coast in the inner Bah´ıa Blanca estuary near bathing waters, i.e. the Maldonado Municipal pool.Fil: Pierini, Jorge Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Campuzano, Francisco Javier. Technical University of Lisbon; PortugalFil: Marcovecchio, Jorge Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Perillo, Gerardo Miguel E.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentin

Suspended sediment contribution resulting from bioturbation in intertidal sites of a SW Atlantic mesotidal estuary: data analysis and numerical modelling

The suspended sediment contribution arising from the bioturbation activity of Neohelice granulata at intertidal sites of the Bahía Blanca estuary was analysed using several approaches, ranging from field experiments to numerical modelling. Crabs from the mudflat remove, trap and erode more sediment from their burrows per unit area than those from saltmarshes, as a consequence of the high population density and the mobility of cohesive sediments. The results obtained through the MOHID simulations showed that the sediments that were bioavailable in the intertidal of Puerto Cuatreros were maintained in the water column much longer than sediments in Villa del Mar. This longer residence time in the area could be because of the geomorphological and hydrodynamic characteristics of the internal area of the estuary, where numerous tidal channels coexist and phenomena of “retention” occur before entry into the main channel. By contrast, in Villa del Mar, located in the middle of the estuary, the sediments are affected by a greater water depth and higher tidal current speeds. In addition, the waves caused by the winds can be a determining factor in the spatio-temporal evolution of the bioavailable sediment in the water column of the study areas.La contribución del sedimento en suspensión debido a la actividad de bioturbación de Neohelice granulata en diferentes sitios intermareales del estuario de Bahía Blanca, se analizó utilizando diferentes enfoques. Estos enfoques van desde experimentos de campo hasta modelos numéricos. Los cangrejos de la planicie de marea remueven, atrapan y erosionan más sedimentos de sus galerías por unidad de área que los de las marismas, como consecuencia de la alta densidad de población y la movilidad de los sedimentos cohesivos. Los resultados obtenidos a través de las simulaciones MOHID mostraron que aquellos sedimentos biodisponibles en la zona intermareal de Puerto Cuatreros se mantuvieron en la columna de agua mucho más tiempo que los sedimentos de Villa del Mar. Este tiempo de residencia más prolongado en la zona podría deberse a la geomorfología y características hidrodinámicas del área interna del estuario, donde numerosos canales de mareas coexisten y se producen fenómenos de “retención” antes de ingresar al Canal Principal. Por el contrario, en Villa del Mar, ubicado en el medio del estuario, los sedimentos se ven afectados por una mayor profundidad de agua y mayores velocidades de corriente de marea. Además, las olas causadas por los vientos pueden ser un factor determinante en la evolución espacio-temporal del sedimento biodisponible en la columna de agua de las áreas de estudio

Colorado River (Argentina) Water Crisis Scenarios and Influence on Irrigation Water Quality Conditions

The characterization and evaluation of water quality in the Valle Bonaerense del Río Colorado (VBRC), Buenos Aires, Argentina, is necessary, given the immense importance of this region for sustaining the population livelihoods and maintaining the ecological balance, especially in the face of drought and climate change scenarios, and loss of crop production yields. This study evaluated the possible reuse of drainage canals from the perspective of their use for irrigation. Surface water samples were collected at four sampling sites during 2015–2021, one over the Colorado river entering the VBRC, and the remaining three drainage canals flow into the Atlantic Ocean. These physicochemical parameters were performed following the protocols proposed using standard methods: total dissolved solids, pH, electrical conductivity (EC), calcium, magnesium, sodium, potassium, carbonates, bicarbonates, chlorides, sulfates and sodium adsorption ratio were analyzed and classified. The irrigation water quality index (IWQI), principal component analysis, hierarchy of classes analysis and statistical analysis were applied to the dataset. The general hydrochemistry of the VBRC river water indicates a slightly alkaline nature, with a mean pH value of 8.03, and the predominance order of the major ions follows the pattern of Na+ > Ca2+ > Mg2+ > K+, and SO42− > Cl− > HCO3− + CO32− for the anions. For the IWQI, 88.06% of the samples analyzed were classified as safe water for irrigation, and a theoretical yield loss was estimated for crops considering the salinity variable, with vegetables showing the highest losses. The surface water from rivers increases the EC due to the decrease in its discharge because of the water crisis affecting Latin America. Water reuse could be useful for one of the three drainage canals. This study concludes that the reuse of drainage water (S2) has great potential as an adaptation strategy to address the water scarcity and climate change challenges in the Colorado river basin. The research highlights the importance of considering this alternative to achieve sustainable water management in the region. Moreover, the data obtained from the study can be used for making policy and resource management decisions. In view of the possible scenarios of low water flow and increases in the EC values, it is recommended to reorient agricultural production toward crops with higher tolerance to salinity as an alternative, to ensure the sustainability and viability of production in the basin.EEA Hilario AscasubiFil: Trillini, Mariano. Universidad Nacional del Sur. Departamento de Química. INQUISUR; ArgentinaFil: Trillini, Mariano. Provincia de Buenos Aires. Comisión de Investigaciones Científicas; ArgentinaFil: Pierini, Jorge Omar. Universidad Nacional del Sur. Departamento de Química. INQUISUR; ArgentinaFil: Pierini, Jorge Omar. Provincia de Buenos Aires. Comisión de Investigaciones Científicas; ArgentinaFil: Vallese, Federico Danilo. Universidad Nacional del Sur. Departamento de Química. INQUISUR; ArgentinaFil: Dunel Guerra, Luciana Gisele. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Hilario Ascasubi; ArgentinaFil: Pistonesi, Marcelo Fabian. Universidad Nacional del Sur. Departamento de Química. INQUISUR; ArgentinaFil: Pistonesi, Marcelo Fabian. Provincia de Buenos Aires. Comisión de Investigaciones Científicas; Argentin

Spatio-temporal variability in the Brazil-Malvinas Confluence Zone (BMCZ), based on spectroradiometric MODIS-AQUA chlorophyll-a observations

The Brazil—Malvinas Confluence Zone (BMCZ) is characterized by high environmental variation, which could be reflected in several optical types of water, from one containing only phytoplankton and sea water to other optically more complex. In this paper, we analyze the spatio-temporal variability of the Chlorophyll-a detected by the ocean color sensor (CHLAsat) in BMCZ in order to understand its environmental variability. We use the MODIS-Aqua CHLAsat monthly composites imagery from 2002 to 2015, and applied two statistical methods: the correlogram-based robust periodogram to identify, over a broad spectrum of temporal, the most significant periodicities, and the pixel gradient distribution to study the spatial-temporal gradients within the BMCZ and variations over the continental shelf and coastal waters. Our results point out to the predominance of the annual cycle over most of the investigated area, although an area from latitude 378S in direction NE, alongshore of Uruguay to Brazil, evidences interannual periodicities, possibly related to variations in the discharge of the Rio de la Plata associated with the El Niño phenomena. The ocean color spectroradiometric signature in terms of pixel gradient presents a relatively high variability (0.0 to 0.65 mg m 3 ); in particular the high values of the pixel gradient correspond to saline front of the estuarine system of Rio de la Plata, and to the strip of the platform that extends along the isobaths of 80 m (coast of Uruguay), especially in the center and south of the study area

Changes in seasonal streamflow extremes experienced in rivers of Northwestern South America (Colombia)

A measure of the variability in seasonal extreme streamflow was estimated for the Colombian Caribbean coast, using monthly time series of freshwater discharge from ten watersheds. The aim was to detect modifications in the streamflow monthly distribution, seasonal trends, variance and extreme monthly values. A 20-year length time moving window, with 1-year successive shiftments, was applied to the monthly series to analyze the seasonal variability of streamflow. The seasonal-windowed data were statistically fitted through the Gamma distribution function. Scale and shape parameters were computed using the Maximum Likelihood Estimation (MLE) and the bootstrap method for 1000 resample. A trend analysis was performed for each windowed-serie, allowing to detect the window of maximum absolute values for trends. Significant temporal shifts in seasonal streamflow distribution and quantiles (QT), were obtained for different frequencies. Wet and dry extremes periods increased significantly in the last decades. Such increase did not occur simultaneously through the region. Some locations exhibited continuous increases only at minimum QT

Saltwater Intrusion into a River with High Fluvial Discharge: A Microtidal Estuary of the Magdalena River, Colombia

The Magdalena River (Bocas de Ceniza) forms a microtidal estuary subjected to numerous interventions aimed to guarantee navigability towards the port of Barranquilla, Colombia. Significant sedimentation processes are still frequent in this area, however. Understanding the dynamics of both saltwater intrusion and mixing conditions is a fundamental requisite to understanding the sedimentation dynamics in these types of estuaries. The effects of river discharge, tide, and winds on stratification patterns, and mixing and saltwater intrusion dynamics in the estuary of the Magdalena River were evaluated, focusing on the effects of river discharge variability. The three-dimensional hydrodynamic model MOHID was implemented, and calibration and validation of the model were carried out using in situ velocity, temperature, and salinity data, obtaining Skill values greater than 0.90. To cover a wide range of variability in the main forcing factors (fluvial discharge, tide, and wind), the conditions recorded in 2010 were simulated when both phases of the El Niño–Southern Oscillation phenomenon occurred. During that year, the river discharge ranged between 2465 and 16,463 m3 s 1. Results revealed a stratified, saltwater wedge estuary, the dynamics of which were mainly dominated by river discharge. Tide and winds altered saltwater intrusion dynamics, mainly during low-discharge periods

Informe científico de investigador: Pierini, Jorge Omar (2017-2018)

El trabajo desarrollado hasta el dia de hoy se halla enmarcado en el análisis de los parámetros meteo-oceanográficos de la ría de Bahia Blanca con el objeto de incorporarlos en una herramienta para la toma de decisión. Especificamente la implementación de modelos numéricos (hidrodinámicos, oleaje y atmosféricos) en la zona. Para ello, se emplearon análisis de datos estadísticos, series de tiempo y modelado numérico, a escala regional y local, de las distintos parámetros oceanográficos teniendo en cuenta los diferentes aportes continentales (calidad de agua, lluvia y caudales). Por otro lado, viendo la falta de información en las series temporales, como por ejemplo la marea, se implementaron métodos de análisis específicos para completar la información faltante. También se analizó la importancia del aporte de sedimento por procesos de bioturbación en el área de estudio y la evaluación de los tiempos de residencia, análisis fundamental para el desarrollo de los procesos intervinientes en la ría. Todo lo mencionado se encuentra avalado por las publicaciones indicadas. Cabe destacar que se esta implementando un modelo biogeoquímico en la ría con la información disponible y que en poco tiempo se tendrán resultados publicados. Además, nos encontramos desarrollando un estudio sobre la cuenca del Río Colorado y su aporte sobre la costa atlántica, con fondos otorgados por la CIC (Res:801/18)