Remote Sensing Of Total Water Storage Variability During Extreme Heat Waves

Droughts and heat waves are a major hazard for food & water security, economic development, and human & ecosystem health, among others. Over the last decade, short-term but exceptional heat waves have been observed across different regions of the world, with several locations experiencing all-time maximum temperature records. While many studies have suggested that the extreme intensity of such recent events can be attributed to a changing climate, little attention has been given to the impacts on the terrestrial water balance. This work analyzes the sensitivity of total water storage to extreme heat waves since 2003 in Europe (2003), Russia, Sahel and Middle East (2010), UK (2011), USA (2012), Australia (2013). The main objectives are to: (1) explore the relationships between temperature, precipitation and total water storage variability (2) infer the response time of extreme dry spells to total water storage decline. The methodology used in this study was based on remote sensing tools such as the GRACE mission and data assimilation from land surface models. The analysis shows recurrent annual hysteresis loops in the monthly time series of climate and water storage, which imply a time lag between the occurrence of heat waves and the depletion of soil moisture and aquifer storage. Finally, the results offer the potential to provide first-order estimates of total water storage variations for large river basins and aquifers due to climate extremes

Evaluation of open-access global digital elevation models (AW3D30, SRTM and ASTER) for flood modelling purposes

Elevation data in the form of Digital Elevation Models (DEMs) has been recognised as a basic piece of information for the accurate representation of topographic controls exerted in hydrologic and hydraulic models. Yet many practitioners rely on open-access global datasets usually obtained from space-borne survey due to the cost and sparse coverage of sources of higher resolution. In may 2016 the Japanese Aerospace eXploration Agency (JAXA) publicly released an open-access global DEM at an horizontal resolution of 30 m, the ALOS World 3D-30m (AW3D30). So far no published study assessed the flood modelling capabilities of this new product. The purpose of this investigation is twofold. Firstly, to present an assessment of the capacity of the AW3D30 DEM for flood modelling purposes and secondly, to compare its performance with regards to computed water levels and flood extent maps calculated using other freely available 30 m DEMs for model setup (e.g. SRTM and ASTER GDEM). For this comparison, the reference to reality is given by the water levels and flood extent maps computed with the same numerical model but using a LiDAR based DEM (5 m of spatial resolution re-sampled to 30 m). The numerical model employed in this investigation is based on a damped partial inertia approximation of the Saint-Venant equations on a regular raster grid, which is forced with a simple and synthetic rainfall storm event. Numerical results using different elevation data in model setup are compared for two regions with contrasting topographic gradients (steep and smooth). Results with regards to water depth and flood extent show that AW3D30 DEM performs better than the SRTM DEM. Notably, in the case of mountainous regions results derived with the AW3D30 DEM are comparable in skill to those obtained with a LiDAR derived DSM, suggesting its suitability in the numerical reproduction of flood events. This encouraging performance paves the way to more accurate modelling for both data-scarce regions and global flood models

Uncertainty Propagation In A Hydro-Meteorological Approach: From The Cloud To The Flood Map.

Globally, it is widely known that floods remain the most frequent and devastating natural hazards. Likewise, there is recent evidence showing an increase in the number of extreme flood events observed around the world. Therefore, it is imperative to develop an integrated flood assessment framework that enables a better understanding of both, the generation of these events and the interaction of key variables within the hydro-meteorological system. The aim of this investigation is to study the propagation of meteorological uncertainty to a numerically estimated flood map. For such purpose, we utilise a cascade modelling approach comprised by a Numerical Weather Prediction Model (NWP), a rainfall-runoff model and a standard 2D hydrodynamic model. Uncertainty is considered in the meteorological model (Weather Research and Forecasting model) using a multi-physics ensemble technique considering twenty four parameterization schemes. The resulting precipitation fields are used as input in a distributed hydrological model to generate spaghetti plots, which are then employed as forcing in a 2D hydrodynamic model. The approach is utilised for the reproduction of an extreme flood event in southern Mexico, for which field data (rain gauges) and satellite imagery are available. Although there are more uncertainties involved in the determination of a flooded area, the methodology represents a robust approach to acknowledge the propagation from the meteorological model to the flood map. Thus, it favours preventive action in the generation of better flood management strategies

Influencia de la marea en la hidrodinámica del sistema Mecoacán-río González, México

El estado de Tabasco, México, es altamente vulnerable a inundaciones. La más grave de los últimos años fue en 2007 y cubrió el 62% de su territorio. A raíz de este suceso surgió el Plan Hídrico Integral de Tabasco, con el objeto de encontrar soluciones para disminuir la vulnerabilidad de la zona ante eventos extremos.Una de ellas consiste en el desvío de grandes caudales hacia el río Samaria, que desemboca al mar por el río González. Este estudio analiza el comportamiento de los flujos del sistema río González-Mecoacán y el rol de la marea en su regulación. En el río González, el flujo hacia el mar es disminuido de forma considerable en pleamar, llegando a detenerse durante mareas vivas. En el río Hondo (que fluye del río González hacia Mecoacán), el flujo llega a revertirse, mientras que en la boca lagunar está modulado por la marea. Esto sugiere que un aumento considerable en el caudal del río González estaría sujeto a un lento drenaje hacia el mar por efecto de la corriente mareal. Lo anterior causaría un aumento del nivel del río y riesgo de inundación en esa zona durante eventos extremos. Las evidencias de penetración de la onda de marea hasta un sitio alejado de la desembocadura del río sugieren que el flujo río arriba podría también estar modulado por la marea. Además, las observaciones termohalinas indican que la salinidad y temperatura cerca de la desembocadura están gobernadas por intrusión salina, mientras que en sitios alejados dependerían de factores atmosféricos

Assessing the rainfall measurements across Mexico City using disdrometer network and their comparison respect to tipping bucket rain gauge network

[EN] This work represents a contribution to the evaluation of the conditions of precipitation observation networks in an urban area, based on the comparison between a network of laser optical disdrometer (LOD) sensors and a network of tipping bucket rain gauges (TB) in Mexico City. In the methodology, 9 LOD stations and 16 TB stations were selected, which were compared in two ways: first,from the total accumulation of precipitation over three years and second, by storm events. The results indicate that the analysis by storm events is more representative than comparing the accumulated precipitation. The measurements are acceptable, as these were checked from linear correlations. It was also determined that the number of events and the distance between the stations contribute to the correlation of the measurements. It is desirable that the methodology can be applied in the periodic quality control of measurements (calibration) and be part of the good practices for the measurement of the urban hydrological cycle at the local level.[ES] Este trabajo representa una contribución para evaluación de las condiciones de las redes de observación de la precipitación en un área urbana, a partir de la comparación entre una red de sensores de disdrómetros ópticos láser (DOL) y una red de pluviómetros de balancín (PB) en la Ciudad de México. En la metodología se seleccionaron 9 estaciones DOL y 16 estaciones PB, las cuales secompararon de dos formas: primero, a partir de la acumulación total de precipitación durante tres años y segundo, por eventos de tormenta. Los resultados indican, que el análisis por eventos de tormenta es más representativo que comparando la precipitaciónacumulada. Las mediciones son aceptables, ya que estas se comprobaron a partir de correlaciones lineales. Asimismo, se determinó que el número de eventos y la distancia entre las estaciones contribuyen en la correlación de las mediciones. Es deseable que la metodología se aplique en el control de calidad periódico de las mediciones (calibración) y sea parte de las buenas prácticas parala medición del ciclo hidrológico urbano a escala local.La autora principal del artículo agradece el apoyo económico recibido por parte del programa de becas de posgrados del Consejo Nacional de Ciencia y Tecnología. También agradece el apoyo del Instituto de Ingeniería de la UNAM y de la Secretaría de Educación, Ciencia, Tecnología e Innovación de la Ciudad de México.Amaro-Loza, A.; Pedrozo-Acuña, A.; Sánchez-Huerta, A.; Sánchez-Vargas, C.; Vergara-Alcaraz, EA. (2022). Evaluación de las mediciones de lluvia en la Ciudad de México utilizando la red de disdrómetros y su comparación con respecto a la red de pluviómetros de balancín. Ingeniería del Agua. 26(2):91-105. https://doi.org/10.4995/ia.2022.172179110526

Flood Risk From Extreme Events In Mexico

Flooding is the most common and damaging natural hazard faced by civilization, and flooding threats are likely to increase given current climate change predictions that suggest more intense hurricanes and precipitation. The latter has been recently experienced in the Mexican state of Guerrero, during the severe flood of September 2013. During this event, the heavy rainfall registered in 2 days (~700 mm) produced extreme river discharges that produced significant fluvial impacts and flooding in large areas of the city of Acapulco, causing severe damages and social disruption. In order to study the causes of this disaster, an integrated methodology to estimate flood risk is utilised. Uncertainties in the results are taken into account through the implementation of a cascade modelling approach, comprised by meteorological, hydrological and hydrodynamic models. These numerical tools are set up with field measurements (e.g. precipitation and bathymetry), and elevation data from a LiDAR-based DEM, enabling the representation and reconstruction of the whole event (from the cloud to the river). This approach allows the assessment of the interaction of natural flows with urban infrastructure and planning in this region. It is shown land use changes may have significantly influenced the extreme flood impacts registered during this event, implying a sensitivity of the region to spatial planning. On the other hand, the estimated return periods of precipitation indicate that the rainfall may be associated to a return period of 100-200 years. Results highlight the need of integration between land-use issues and water issues to achieve a more sustainable and viable management of land and water. The cascade modelling approach may be applied to other areas and can be extended to consider the effect of future climate change

Sobre el uso de las ecuaciones de Navier-Stokes con el promedio de Reynolds en el campo de la ingeniería de costas

En este trabajo se presenta una discusión sobre la utilidad de modelos de propagación de oleaje nolineal en aguas costeras, con particular énfasis en el empleo de modelos de alta resolución (espacial y temporal), basados en las ecuaciones promediadas de Navier-Stokes (RANS). Este tipo de modelos brindan una oportunidad única para realizar estudios detallados de los procesos involucrados en la transformación del oleaje antes y durante la rotura. Para demostrarlo, se presentan ejemplos donde se hace evidente el alto nivel de detalle que se puede alcanzar en la descripción del flujo mediante el uso de este tipo de modelos. Se destaca el rol diagnóstico que poseen, dada su capacidad para el desglose de cada una de las variables involucradas en la rotura del oleaje (por ejemplo, velocidades, turbulencia, gradientes de presión). Para resaltar su amplio rango de aplicación se presentan resultados para dos playas con características y procesos hidrodinámicos asociados distintos. Los resultados numéricos mostrados confirman que estos modelos son una excelente herramienta para el estudio de procesos relacionados con la rotura del oleaje y su evolución en la zona de lavado. Es evidente que la combinación de este tipo de herramientas con mediciones de campo y/o laboratorio tendrá un rol primordial en el desarrollo de la ingeniería de costas en los años venideros

Uncertainty Analysis in Data-Scarce Urban Catchments

The evaluation of the uncertainties in model predictions is key for advancing urban drainage modelling practice. This paper investigates, for the first time in Mexico, the effect of parameter sensitivity and predictive uncertainty in an application of a well-known urban stormwater model. Two of the most common methods used for assessing hydrological model parameter uncertainties are used: the Generalised Likelihood Uncertainty Estimation (GLUE) and a multialgorithm, genetically adaptive multi-objective method (AMALGAM). The uncertainty is estimated from eight selected hydrologic parameters used in the setup of the rainfall-runoff model. To ensure the reliability of the model, four rainfall events varying from 20 mm to 120 mm from minor to major count classes were selected. The results show that, for the selected storms, both techniques generate results with similar effectiveness, as measured using well-known error metrics; GLUE was found to have a slightly better performance compared to AMALGAM. In particular, it was demonstrated that it is possible to obtain reliable models with an index of agreement (IAd) greater than 60 and average Absolute Percentage Error (EAP) less than 30 percent derived from the uncertainty analysis. Thus, the quantification of uncertainty enables the generation of more reliable flow predictions. Moreover, these methods show the impact of aggregation of errors arising from different sources, minimising the amount of subjectivity associated with the model’s predictions

Failure Analysis of a Water Supply Pumping Pipeline System

This paper describes the most important results of a theoretical, experimental and in situ investigation developed in connection with a water supply pumping pipeline failure. This incident occurred after power failure of the pumping system that caused the burst of a prestressed concrete cylinder pipe (PCCP). Subsequently, numerous hydraulic transient simulations for different scenarios and various air pockets combinations were carried out in order to fully validate the diagnostic. As a result, it was determined that small air pocket volumes located along the pipeline profile were recognized as the direct cause of the PCCP rupture. Further, a detail survey of the pipeline was performed using a combination of non-destructive technologies in order to determine if immediate intervention was required to replace PCC pipes. In addition, a hydraulic model was employed to analyze the behavior of air pockets located at high points of the pipeline