João P. Leitão

João P. Leitão
Eawag: Das Wasserforschungs-Institut des ETH-Bereichs | Eawag · Department of Urban Water Management

PhD Civil and Environmental Engineering

About

98
Publications
27,155
Reads
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Citations
Introduction
João P. Leitão works at the Department of Urban Water Management of Eawag: Swiss Federal Institute of Aquatic Science and Technology. João's research focus on exploring new data sources and modelling tools to improve urban drainage modelling and urban flood risk assessment.
Additional affiliations
January 2014 - September 2018
Eawag: Das Wasserforschungs-Institut des ETH-Bereichs
Position
  • Researcher (Group leader on tenure-track)
July 2013 - December 2013
Eawag: Das Wasserforschungs-Institut des ETH-Bereichs
Position
  • Postdoctoral researcher
March 2010 - June 2013
National Laboratory for Civil Engineering
Position
  • Postdoctoral researcher
Education
March 2006 - October 2009
Imperial College London
Field of study
  • Civil and environmental engineering (urban flood modelling)
October 2001 - June 2004
Technical University of Lisbon
Field of study
  • Geographic Information Systems (facility location modelling)
September 1996 - September 2001
Technical University of Lisbon
Field of study
  • Environmental engineering

Publications

Publications (98)
Chapter
This chapter briefly presents concepts and methodologies to support the management of urban drainage infrastructure. After the introduction, data requirements for assessing the condition of urban drainage systems are presented. Data can be collected in different ways. Data analysis allows for determining structural and functional issues and system...
Article
Data-driven and machine learning models have recently received increasing interest to resolve the computational speed challenge faced by various physically-based simulations. A few studies have explored the application of these models to develop new, and fast, applications for fluvial and pluvial flood prediction, extent mapping, and flood suscepti...
Article
Synthetic design storms are often used to plan new drainage systems or assess flood impacts on infrastructure. To simulate extreme rainfall events under climate change, design storms can be modified to match a different return frequency of extreme rainfall events as well as a modified temporal distribution of rainfall intensities. However, the same...
Article
Understanding the negative effects of widespread implementation of optimal water efficient solutions may have on existing centralised sewer systems is still limited – one of these effects is the accumulation of solids in sewer pipes. Predicting these effects requires setting up and simulating complex detailed hydraulic sewer network models. Often,...
Article
Full-text available
Thermal-hydraulic considerations in urban drainage networks are essential to utilise available heat capacities from waste- and stormwater. However, available models are either too detailed or too coarse; fully coupled thermal-hydrodynamic modelling tools are lacking. To predict efficiently water-energy dynamics across an entire urban drainage netwo...
Article
Recurring combined sewer overflows (CSOs) can have a significant impact on the ecological condition of receiving water bodies. There are several structural measures, like adding retention basins and switching to low impact development solutions, that have been proposed to reduce the number of sewage overflows. Besides, several flow control strategi...
Preprint
Full-text available
Thermal-hydraulic considerations in urban drainage networks are essential to utilise available heat capacities from waste- and stormwater. However, available models are either too detailed or too coarse; fully coupled thermal-hydrodynamic modelling tools are lacking.To accurately predict water-energy dynamics across an entire urban drainage network...
Article
Full-text available
In many parts of the world, small towns are experiencing high levels of population growth and development. However, there is little understanding of how urban growth in these regional towns will impact urban runoff. We used the case study of Wangaratta, located in South-East Australia, between 2006 and 2016, to investigate land cover changes and th...
Article
Two‐dimensional hydrodynamic models numerically solve full Shallow Water Equations (SWEs). Despite their high accuracy, these models have long simulation run times and therefore are of limited use for exploratory or real‐time flood predictions. We investigated the possibility of improving flood modelling speed using Machine Learning (ML). We propos...
Article
Full-text available
Computational complexity has been the bottleneck for applying physically based simulations in large urban areas with high spatial resolution for efficient and systematic flooding analyses and risk assessment. To overcome the issue of long computational time and accelerate the prediction process, this paper proposes that the prediction of maximum wa...
Article
Full-text available
Sustainable urban drainage systems (SuDS) help in stormwater management by reducing runoff volume, increasing runoff concentration time and thereby improving the drainage system capacity. This study investigated the potential and cost-effectiveness of SuDS in reducing combined sewer overflows (CSOs). We simulated the performance of four SuDS techni...
Article
Full-text available
Floods are among the most frequent and catastrophic natural disasters and affect millions of people worldwide. It is important to create accurate flood maps to plan (offline) and conduct (real-time) flood mitigation and flood rescue operations. Arguably, images collected from social media can provide useful information for that task, which would ot...
Preprint
Full-text available
Floods are among the most frequent and catastrophic natural disasters and affect millions of people worldwide. It is important to create accurate flood maps to plan (offline) and conduct (real-time) flood mitigation and flood rescue operations. Arguably, images collected from social media can provide useful information for that task, which would ot...
Preprint
Full-text available
Computational complexity has been the bottleneck of applying physically-based simulations on large urban areas with high spatial resolution for efficient and systematic flooding analyses and risk assessments. To address this issue of long computational time, this paper proposes that the prediction of maximum water depth rasters can be considered as...
Article
Urban pluvial flood models need to be calibrated with data from actual flood events in order to validate and improve model performance. Due to the lack of conventional sensor solutions, alternative sources of data such as citizen science, social media, and surveillance cameras have been proposed in literature. Some of the methods proposed boast hig...
Article
The Portuguese discovered the uninhabited Azores archipelago in 1427 and started to settle it during the fifteenth century. Angra, located on Terceira Island, soon became the most important Azorean city, leading to rapid urban development. This article investigates the overlooked role of streams in the rise of Angra as a pivotal Atlantic urban cent...
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Sewer asset management gained momentum and importance in recent years due to economic considerations , since infrastructure maintenance and rehabilitation directly represent major investments. Because physical urban water infrastructure has life expectancies of up to 100 years or more, contemporary urban drainage systems are strongly influenced by...
Article
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Urban flooding poses an increasing threat to citizens and property and has become a global challenge. The primary cause of urban flooding is rapid urbanization, which is outpacing infrastructure development and drainage system improvements. This paper utilizes a verified flood model that couples hydrological and hydrodynamic processes to investigat...
Article
Full-text available
Multi-criteria decision models have been recently implemented in many urban flood risk management schemes due to the increasing demand of low-cost and reliable solutions to prevent and control overflow from sewer systems. Based on specific targets, these decision models encompass multiple reward (or objective) functions according to socio-economic...
Article
Full-text available
In many countries, urban flooding due to local, intense rainfall is expected to become more frequent because of climate change and urbanization. Cities trying to adapt to this growing risk are challenged by a chronic lack of surface flooding data that are needed for flood risk assessment and planning. In this work, we propose a new approach that ex...
Article
Comprehensive management of urban drainage network infrastructure is essential for sustaining the operation of these systems despite stresses from component deterioration, urban densification, and a predicted intensification of rainfall events. In this context, up-to-date and accurate urban drainage network data is key. However, such data is often...
Article
Full-text available
Urban water systems are being redefined for a digital age, promising substantial advantages for service users and providers, and for society as a whole. However, beside the much-discussed benefits of smart urban water systems in future smart cities, the transition will also bring unique challenges, particularly with respect to privacy and cybersecu...
Article
Full-text available
Ubiquitous sensing will create many opportunities and threats for urban water management, which are only poorly understood today. To identify the most relevant trends, we conducted a horizon scan regarding how ubiquitous sensing will shape the future of urban drainage and wastewater management. Our survey of the international urban water community...
Article
Full-text available
In the event of a flood, being able to build accurate flood level maps is essential for supporting emergency plan operations. In order to build such maps, it is important to collect observations from the disaster area. Social media platforms can be useful sources of information in this case, as people located in the flood area tend to share text an...
Preprint
Full-text available
In many countries, urban flooding due to local, intense rainfall is expected to become more frequent because of climate change and urbanization. Cities trying to adapt to this growing risk are challenged by a chronic lack of surface flooding data that is needed for flood risk assessment and planning. In this work, we propose a new approach that exp...
Preprint
Physically-based overland flow models are computationally demanding, hindering their use for real-time applications. Therefore, the development of fast (and reasonably accurate) overland flow models is needed if they are to be used to support flood mitigation decision making. In this study, we investigate the potential of Self-Organizing Maps to ra...
Article
Physically-based models are important tools for evaluating the hydraulic behaviour of urban drainage systems and, more specifically, assessing flood risk. While it is well known that such models should be calibrated and validated with monitoring data, overland runoff information is seldom available for this purpose. This study investigates the pote...
Preprint
Flood prediction in a synthetic trapezoidal, com-pound channel is made, using an emulator of thecomputationally demanding 2D hydrodynamicmodel FLOW-R2D.
Article
Full-text available
Sewer and drainage infrastructure are often not as well catalogued as they should be, considering the immense investment they represent. In this work, we present a fully automatic framework for localizing sewer inlets from image clouds captured from an unmanned aerial vehicle (UAV). The framework exploits the high image overlap of UAV imaging surve...
Article
When defining the variables to predict sewer failure and therefore optimise sewer systems maintenance, it is important to identify the ones that most significantly influence the quality of the predictions or to define the smallest number of variables that is sufficient to obtain accurate predictions. In this study, three different statistical varia...
Article
Newly available, more detailed and accurate elevation data sets, such as Digital Elevation Models (DEMs) generated on the basis of imagery from terrestrial LiDAR (Light Detection and Ranging) systems or Unmanned Aerial Vehicles (UAVs), can be used to improve flood-model input data and consequently increase the accuracy of the flood modelling result...
Article
The activation of available in-sewer storage volume has been suggested as a low-cost flood and combined sewer overflow mitigation measure. However, it is currently unknown what the attributes for suitable objective functions to identify the best location for flow control devices are and the impact of those attributes on the results. In this study,...
Presentation
Full-text available
Floods are among the most destructive catastrophic events and their frequency has incremented over the last decades. To reduce flood impact and risks, flood warning schemes are installed in flood prone areas. Frequently, these schemes are based on numerical models which quickly provide predictions of water levels and other relevant observables. How...
Article
Full-text available
Hexagonal segmentations of space have long been known for their advantages vis à vis squared partitions in discretizing spatial variables, be it natural phenomena or human-related features. However, readily available and easy-to-use tools to manipulate and interact with hexagonal rasters remain widely unavailable today. This article presents a firs...
Article
Full-text available
Sewer inlet structures are vital components of urban drainage systems and their operational conditions can largely affect the overall performance of the system. However, their hydraulic behaviour and the way in which it is affected by clogging is often overlooked in urban drainage models, thus leading to misrepresentation of system performance and,...
Conference Paper
Full-text available
Urban flooding events which are often caused by a lack of capacity of the urban collecting system, can be a risk to human life. The CENTAUR project is developing an innovative, cost effective, local and autonomous sewer flow control system to reduce urban flood risk. The CENTAUR system consists of a flow control device controlled by a Fuzzy Logic a...
Conference Paper
Full-text available
This paper evaluates the impact of time-varying clogging conditions of sewer inlets in an urban catchment in Coimbra, Portugal. The calibrated 1D/2D model was updated with inlet capacity curves, which consider different durations from the cleaned condition to several clogging limits. The set of curves applied represent several operational condition...
Conference Paper
Full-text available
In the floodX project, over 30 controlled flash flood events were staged in a military training village. Thanks to the large number and diversity (e.g., security cameras) of sensors used, the resulting datasets offer a unique opportunity to (i) develop alternative flood monitoring methods using computer vision and (ii) develop calibration schemes c...
Conference Paper
Full-text available
In this study we explore the potential advantages of the hexagonal meshes for cellular automata-based flood modelling applications. We conduct a set of flood simulations and compare the quality of the modelling results in terms of water depth and flow velocity for the square and hexagonal cell geometries. The results showed that water depths obtain...
Article
Full-text available
The data sets described in this paper provide a basis for developing and testing new methods for monitoring and modelling urban pluvial flash floods. Pluvial flash floods are a growing hazard to property and inhabitants' well-being in urban areas. However, the lack of appropriate data collection methods is often cited as an impediment for reliable...
Article
Tree roots cause significant and costly damage to sewer systems. However, the contributions made by tree and sewer characteristics to sewer system damage are not yet well understood. Previous research has proved inconclusive and there is a lack of agreement on the importance of the variables involved, which means that the results cannot be extrapol...
Article
Full-text available
The datasets described in this paper are intended to provide a basis on which new methods for monitoring and modelling urban pluvial flash floods can be developed. Pluvial flash floods are a growing hazard to property and inhabitants' well-being in urban areas. However, the lack of appropriate data collection methods is often cited as an impediment...
Article
Full-text available
Urban floods are becoming more frequent. Thus, the European Union published the Directive 2007/60/CE to mitigate costs related with this phenomenon and to impose limits on the concentration of pollutants in pluvial water. The purpose of this study was to present the modelling of drainage systems in flood situations, based on the software of the Uni...
Conference Paper
Full-text available
The newly available and more detailed and accurate elevation data sets, such as Digital Elevation Models (DEMs) generated from imagery acquired using terrestrial LiDAR (Light Detection and Ranging) and Unmanned Aerial Vehicles (UAVs), can be used to improve flood model input data and consequently increase accuracy of flood modelling results. In thi...
Presentation
Full-text available
Preliminary results of Eawag’s work on the CENTAUR project. An extended abstract can be found in the conference proceedings.
Conference Paper
Full-text available
When new methodologies are tested, several case studies are needed for validation and generalisation. However, for a researcher, it is difficult to obtain a large number of case studies, not only because real data is limited, but also because designing a model is a time consuming task. The Storm Water Management Model (SWMM) is a Free and Open Sour...
Article
Many model based scientific and engineering methodologies, such as system identification, sensitivity analysis, optimization and control, require a large number of model evaluations. In particular, model based real-time control of urban water infrastructures and online flood alarm systems require fast prediction of the network response at different...
Presentation
Full-text available
Presentation to the CAMUSS 2016 conference held in Québec. Presents early results of the hexagonal grid implementation of the rapid flood model CAFlood using the CADDIES cellular automata framework.
Conference Paper
Full-text available
During the last decades a holistic approach has been proposed for the design of urban drainage systems. The involvement of sustainability concepts has widened the possibilities in terms of obtaining simultaneous benefits that exceeds the sole objective of control of urban flooding (Scholz, 2014). This multi-objective approach became a high complexi...
Article
Full-text available
Precise and detailed digital elevation models (DEMs) are essential to accurately predict overland flow in urban areas. Unfortunately, traditional sources of DEM, such as airplane light detection and ranging (lidar) DEMs and point and contour maps, remain a bottleneck for detailed and reliable overland flow models, because the resulting DEMs are too...
Article
Failure prediction plays an important role in the management of urban water systems infrastructures. An accurate description of the deterioration of urban drainage systems is essential for optimal investment and rehabilitation planning. In the study presented in this paper, a new method to predict sewer pipe failure based on robust decision trees i...
Article
Digital Elevation Models (DEMs) are used to represent the terrain in applications such as, for example, overland flow modelling or viewshed analysis. DEMs generated from digitising contour lines or obtained by LiDAR or satellite data are now widely available. However, in some cases, the area of study is covered by more than one of the available ele...
Article
Full-text available
Modelling rainfall–runoff in urban areas is increasingly applied to support flood risk assessment, particularly against the background of a changing climate and an increasing urbanization. These models typically rely on high-quality data for rainfall and surface characteristics of the catchment area as model input. While recent research in urban d...
Article
Full-text available
It is a common practice to assign the return period of a given storm event to the urban pluvial flood event that such storm generates. However, this approach may be inappropriate as rainfall events with the same return period can produce different urban pluvial flooding events, i.e., with different associated flood extent, water levels and return p...
Article
Full-text available
This review describes and compares statistical failure models for water distribution pipes in a systematic way and from a unified perspective. The way the comparison is structured provides the information needed by scientists and practitioners to choose a suitable failure model for their specific needs. The models are presented in a novel framework...