Methodology to quantify clogging coefficients for grated inlets: application to SANT MARTI catchment (Barcelona)

This is the accepted version of the following article: Gómez, M, Parés, J, Russo, B, Martínez‐Gomariz, E. Methodology to quantify clogging coefficients for grated inlets. Application to SANT MARTI catchment (Barcelona). J Flood Risk Management. 2019; 12:e12479. https://doi.org/10.1111/jfr3.12479, which has been published in final form at https://onlinelibrary.wiley.com/doi/10.1111/jfr3.12479.Within the drainage system of a city, the set of inlets is in charge of taking the runoff produced by local storms to the stormwater/sewer. In the drainage system design the selection of appropriate inlet models and their location is one of the fundamental aspects. The hydraulics of these inlets has received great attention within the last years; however, few inlet makers provide the hydraulic capacity of their products. In addition, these data usually consider clean water, while in reality, numerous inlets can be either totally or partially clogged. This aspect should be kept in mind within the design process. In this paper, a methodology to consider the hydraulic effects of clogging phenomena is presented. The work started from a visual inspection of the grated inlets throughout the urban catchment of Sant Martí, Barcelona, as a means of identifying clogging patterns, their repetitive forms and their associated frequency. After that, clogged patterns were reproduced in laboratory testing of typical inlets types, thereby obtaining the real quantity of water that could be captured by each of them. It was shown that the same expression employed to describe the efficiency of clean inlets can be used to assess the efficiency of those clogged. A reduction factor in terms of hydraulic capacity and related to each clogging pattern has been defined for use in hydraulic studies of runoff along streets. Finally, the paper compares the obtained results in terms of clogging coefficient with another experimental campaign carried out in other catchment of the city.Peer ReviewedPostprint (author's final draft

Assessment of inlet efficiency through a 3D simulation: numerical and experimental comparison

Inlet efficiency is a requirement for characterizing the flow transfers between surface and sewer flow during rain events. The dual drainage approach is based on the joint analysis of both upper and lower drainage levels, and the flow transfer is one of the relevant elements to define properly this joint behaviour. This paper presents the results of an experimental and numerical investigation about the inlet efficiency definition. A full scale (1:1) test platform located in the Technical University of Catalonia (UPC) reproduces both the runoff process in streets and the water entering the inlet. Data from tests performed on this platform allow the inlet efficiency to be estimated as a function of significant hydraulic and geometrical parameters. A reproduction of these tests through a numerical three-dimensional code (Flow-3D) has been carried out simulating this type of flow by solving the RANS equations. The aim of the work was to reproduce the hydraulic performance of a previously tested grated inlet under several flow and geometric conditions using Flow-3D as a virtual laboratory. This will allow inlet efficiencies to be obtained without previous experimental tests. Moreover, the 3D model allows a better understanding of the hydraulics of the flow interception and the flow patterns approaching the inlet.Preprin

A new experiments-based methodology to define the stability threshold for any vehicle exposed to flooding

This is an Accepted Manuscript of an article published by Taylor & Francis Group in Urban water journal on 2017, available online at: http://www.tandfonline.com/doi/full/10.1080/1573062X.2017.1301501A vehicle exposed to flooding, after losing stability, becomes buoyant and may be washed away with potential injuries and fatalities. Such vehicles cause additional disruption to traffic that is already affected by flooding, which may lead to substantial indirect economic impact, especially in urban areas. Therefore, the analysis of the stability of vehicles exposed to flooding is important in order to make decisions to reduce damages and hazards. In this research, based on an experimental campaign that included a range of twelve car models, a new methodology to obtain the stability threshold for any real vehicle exposed to flooding is developed. A stability coefficient (SCmod) is derived with which the vehicles can be sorted by stability against water flows and their stability functions may be determined. The experiments were conducted with three different model scales (1:14, 1:18 and 1:24) and involved analysis of both friction and buoyancy effects, which made this the most comprehensive research study to date. This methodology enables the definition of a stable area in the flow depth-velocity domain for any real vehicle. A tool is provided that decision-makers in the field of urban flood risk management can employ and after defining a design vehicle they can obtain its corresponding stability threshold.Peer ReviewedPostprint (author's final draft

Toward sustainable management: 2D modelling of a self-cleaning system to improve geometry in front of the flushing gate

This paper aims to show how numerical modelling based on 2D SWE can be used to analyze the cleaning effectiveness of flushing waves in storm tanks. The case study under consideration is an existing storm tank located in Badalona, a municipality of Barcelona, Spain. Storm tank cleaning systems are critical features that must be carefully addressed. If not appropriately addressed, operation and maintenance work costs can drastically increase. There are numerous currently available technologies for cleaning storage tanks. However, no specific guide on this field has been identified. References are provided by the manufacturers through their commercial catalogues. Generally, this information is not based on experimental or numerical experiences or results have not been published in the literature of scientific papers. In this study, a public domain software (IBER) was used to develop 2D hydraulic analysis of the selected tank. The results obtained show how the phenomenon of recirculation is acting in some areas of the lane. This implies a dissipation of energy, thus causing difficulties in terms of cleaning procedures. Furthermore, two new scenarios have been tested to determine how a different lane width might affect hydrodynamic behavior. A newly suggested geometry for the existing lane of the tank is proposed by using the numerical modeling software. The proposed geometry in the current pilot tank achieves higher velocities and avoids recirculation areas. The results demonstrate that numerical modelling of these types of processes is possible with the computer models available (commercial codes) and can be used to optimize cleaning system designPeer ReviewedPostprint (published version

Experimental study of the stability of pedestrians exposed to urban pluvial flooding

The final publication is available at Springer via http://dx.doi.org/10.1007/s11069-016-2242-zPopulations in urban environments are extremely mobile throughout the day and in various weather conditions; accounting for this pedestrian mobility and security becomes high importance. Research into the security and stability of the pedestrian environment under exposure to critical water flows provides an essential knowledge base with which the associated hazard unto them can be critically evaluated. This research seeks to analyse degrees of hazard in relation to persons exposed to high-volume rain events in urban areas. Several human trials of critical urban flows were conducted in order to determine the stability limits of pedestrians, crossing through a water flow in a real-scale physic model. Additionally, the critical first step from a dry footpath into fast-flowing water is considered and an assessment of the tested subjects' emotional responses when entering and crossing flooded roadways was carried out. Results from this study are compared with various proposed human stability criteria as well as alternatives proposed in other written works. The presented study offers a stability threshold focused on shallow depths and high-velocity conditions, the most common urban flooding conditions.Peer ReviewedPostprint (author's final draft

Quantification of energy loss in two grated inlets under pressure

Grated inlets have the normal function of collecting the surface runoff into sewer networks, but when the flow exceeds the capacity of the sewer pipes and conduits get pressurized, an outflow from the sewer manholes and grates can occur. In this case, the grate produces an energy loss in the outflow from sewer to street that could be hydraulically quantified characterizing this kind of flow. Energy loss analysis in trash racks can be found in technical literature, but no specific studies on sewer grate inlets have been found. For this reason, some experiments in full scale were developed in the hydraulic laboratory of the Technical University of Catalonia (UPC) in order to quantify hydraulic energy losses associated with flow through grated inlets during surcharging conditions. The main goal of this research work was to experimentally quantify the values of the local loss coefficient k for two different surcharged real scale grated inlets existing in Barcelona. For the tested overflows between 20 and 50 L/s, a range from 0.25 to 3.41 was observed for k coefficients under different average velocities of reference and different flow conditions.Peer ReviewedPostprint (published version

Stability criteria for flooded vehicles: a state-of-the-art review

This is the accepted version of the following article: [Martínez-Gomariz, E., Gómez, M., Russo, B. and Djordjević, S. (2018), Stability criteria for flooded vehicles: a state-of-the-art review. Journal of Flood Risk Management, 11: S817–S826. doi: 10.1111/jfr3.12262], which has been published in final form at http://onlinelibrary.wiley.com/wol1/doi/10.1111/jfr3.12262/abstract.Hazard conditions related to vehicular circulation are important in flood risk management. The knowledge of vehicles stability when those are exposed to flooding is crucial for an informed flood risk management in urban areas. After losing stability, the vehicle becomes buoyant and may be washed away with potential injuries and fatalities. Therefore, the analysis of the stability of vehicles exposed to flooding is important in order to make decisions to reduce the damages and hazards. Herein a comprehensive state-of-the-art on stability of vehicles exposed to flooding is presented. The different studies have been gathered in experimental, theoretical and guidelines proposals and all of them focusing on parked vehicles. There is a clear need to conduct more research in this field by testing a greater variety of models in order to offer a more general methodology to define stability threshold for any vehicle exposed to flooding. Nevertheless, in this work, it has been demonstrate that the most safety stability criterion for vehicles exposed to flooding up to now is the proposed in the Guide AR&R.Peer ReviewedPostprint (author's final draft

Detección y cuantificación de vertidos. Análisis de un caso real en Zaragoza

Ll Real Decreto 1290/2012, en su disposición tercera, establece que los vertidos de aglomeraciones urbanas superiores a 50.000 h.e., de más de 2000 h.e. o zonas industriales situadas en zonas incluidas en el Registro de Zonas Protegidas, o de instalaciones industriales que requieran de Autorización Ambiental Integrada, de-berán dotar a los puntos de desbordamiento de sistemas de cuantificación de alivios como máximo antes del 31 de diciembre de 2019. Con el fin de determinar, cuantificar y reducir los impactos de las DSU sobre los medios receptores se implanta un sistema de monitorización. El sistema de monitorización comprende el conjunto de sensores térmicos, de turbidez, un sensor radar de nivel y el sistema de alimentación de red. Para la medida de la frecuencia y la duración de los vertidos se plantea la posibi-lidad de utilizar dos sensores de temperatura, como alternativa "low-cost" a los de sensores de nivel. La creación de un programa empleando lenguaje de macros VBA (Visual Basic for Applications) permite quw la información proporcionada por los sensores quede sintetizada de forma cuantitativa para su consulta

Estudio y dimensionamiento de un depósito de retención de sólidos en el Barrio de Juslibol (Zaragoza)

El desarrollo urbanístico llevado a cabo en las ciudades en las últimas décadas ha provocado que muchas zonas se hayan desnaturalizado provocando inundaciones en sus calles con el consiguiente malestar entre los vecinos. Este problema es agravado en climas semi-áridos donde los eventos de lluvia se dan con duraciones muy cortas pero muy intensas. Además en este tipo de climas y con estas intensidades se da una erosión del terreno que provoca arrastre de sólidos en la cuenca. El objetivo de el presente Trabajo Fin de Grado es el de estudiar posibles soluciones para evitar que las inundaciones lleguen al núcleo urbano, derivando ese caudal a un punto de desagüe adecuado pero sin áridos. Para conseguir estos objetivos se han estudiado dos posibles soluciones, una superficial y otra subterránea con sus correspondientes ventajas y desventajas

Evaluación de los efectos del cambio climático en los problemas de inundación de la villa de La Almunia de Doña Godina (Zaragoza)

Las inundaciones en España constituyen el riesgo natural que a lo largo del tiempo ha producido los mayores daños tanto materiales como en pérdida de vidas humanas. La Directiva 2007/60/CE relativa a la evaluación y gestión de los riesgos de inundación considera que las inundaciones son fenómenos naturales que no pueden evitarse. No obstante, algunas actividades humanas y el cambio climático están contribuyendo a aumentar las probabilidades de que ocurran, así como su impacto negativo. Las emisiones mundiales del GEI por efecto de actividades humanas han aumentado, en un 70% entre 1970 y 2004 y las concentraciones atmosféricas mundiales del CO2, metano y óxido nitroso han aumentado desde 1750. En un contexto de alta incertidumbre acerca de las variables hidro-climáticas, se ha decidido evaluar el efecto del cambio climático en los problemas de inundación de la villa de La Almunia de Doña Godina (Zaragoza) en el marco del proyecto Escena para el horizonte 2050. La ocurrencia de eventos extremos de lluvia, en ocasiones provoca que el sistema de drenaje sea incapaz de evacuar la escorrentía superficial. El resultado es una inundación de la zona urbana, causando problemas de circulación para vehículos y personas, daños materiales, e incluso la pérdida de vidas humanas. En este contexto, es clara la necesidad de contar con herramientas numéricas para reproducir eventos extremos de lluvia y analizar el comportamiento hidrológico e hidráulico. Por ello el objetivo del presente Trabajo Fin de Grado es crear en primer lugar el modelo hidrológico a través del software HEC-HMS de los barrancos de Fontellas y Cantalobos causantes de los problemas de inundación en la villa y posteriormente un modelo bidimensional en InfoWorks RS para analizar el comportamiento hidráulico en el Casco Antiguo de La Almunia de Doña Godina para los periodos de retorno 10, 25 y 100 años