Jeffrey C Neal

• PhD University of Southampton
• Professor (Associate) at University of Bristol

Global flood mapping has developed rapidly over the past decade, but previous approaches have limited scope, function, and accuracy. These limitations restrict the applicability and fundamental science questions that can be answered with existing model frameworks. Harnessing recently available data and modeling methods, this paper presents a new gl...

Flood event set generation, as employed in catastrophe risk models, relies on gauge information that is not available in data‐scarce regions. To overcome this limitation, we develop a stochastic fluvial and pluvial flood model of Southeast Asia, using freely and globally available discharge data from the global hydrological model GloFAS and rainfal...

Typical flood models do not take into consideration the spatial structure of flood events, which can lead to errors in the estimation of flood risk at regional to continental scales. Large‐scale stochastic flood models can simulate synthetic flood events with a realistic spatial structure, although this method is limited by the availability of gaug...

The term ‘system’ is prominently used in connection with resilience to describe the associated processes of resistance, absorption, accommodation, and recovery to hazard exposure. Essentially, these associated processes are complex in nature but, in an elementary sense, they are maintained through preservation and restoration of essential structure...

Current flood risk mapping, relying on historical observations, fails to account for increasing threat under climate change. Incorporating recent developments in inundation modelling, here we show a 26.4% (24.1–29.1%) increase in US flood risk by 2050 due to climate change alone under RCP4.5. Our national depiction of comprehensive and high-resolut...

Geodetic altimeters provide unique observations of the river surface longitudinal profile due to their long repeat periods and densely spaced ground tracks. This information is valuable for calibrating hydraulic model parameters, and thus, for producing reliable simulations of water level for flood forecasting and river management, particularly in...

Floods can be devastating to society and the environment. Recent events around the globe have been disastrous and broke records in economic losses. Flood disasters often operate at spatial and temporal scales that far exceed local and regional, or even national, assessment and response capabilities. There is no doubt that remote sensing observation...

The growing worldwide impact of flood events has motivated the development and application of global flood hazard models (GFHMs). These models have become useful tools for flood risk assessment and management, especially in regions where little local hazard information is available. One of the key uncertainties associated with GFHMs is the estimati...

Many dryland rivers are terminal systems, with small channels undergoing prominent downstream size reductions before ending on channelless floodplains, in wetlands, or at playa margins. Spaceborne Digital Elevation Models (DEMs) provide potential for assessing subtle topographic and hydrodynamic changes in these low-gradient, low-relief settings, b...

This paper uses a coupled hydrodynamic agent-based model (HABM) to investigate the effect of direct or indirect warnings in flood incident response. This model uses the LISFLOOD-FP hydrodynamic model and the NetLogo agent-based framework and is applied to the 2005 flood event in Carlisle, UK. The hydrodynamic model provides a realistic simulation o...

Global flood models integrate flood maps of constant probability in space, ignoring the correlation between sites and thus potentially misestimating the risk posed by extreme events. Stochastic flood models alleviate this issue through the simulation of flood events with a realistic spatial structure, yet their proliferation at large scales has his...

Hydrodynamic floodplain inundation models have been popular for many years and used extensively in engineering applications. Continental scale flood studies are now achievable using such models due to the development of terrain elevation, hydrography and river width datasets with global coverage. However, deploying flood models at any scale is time...

Levee failures due to floods often cause considerable economic damage and life losses in inundated dike-protected areas, and significantly change flood hazard upstream and downstream the breach location during the event. We present a new extension for the LISFLOOD-FP hydrodynamic model which allows levee breaching along embankments in fully two-dim...

The execution of hydraulic models at large spatial scales has yielded a step change in our understanding of flood risk. Yet their necessary simplification through the use of coarsened terrain data results in an artificially smooth digital elevation model with diminished representation of flood defense structures. Current approaches in dealing with...

Abstract. This paper presents a new flood risk behaviour model developed using a coupled Hydrodynamic Agent-Based Model (HABM). This model uses the LISFLOOD-FP Hydrodynamic Model and the NetLogo (NL) agent-based framework and is applied to the 2005 flood event in Carlisle, UK. The hydrodynamic model provides a realistic simulation of detailed flood...

This study evaluates and compares two-dimensional (2D) numerical models of different complexities by testing them on a floodplain inundation event that occurred on the Secchia River (Italy). We test 2D capabilities of LISFLOOD-FP and HEC-RAS (5.0.3), implemented using various grid sizes (25–100 m) based on 1-m DEM resolution. As expected, the best...

Freely available Global Digital Elevation Models (GDEMs) are essential for many scientific and humanitarian applications. Recently, TanDEM-X 90 has been released with a global coverage at 3 arc sec resolution. Its release is sure to generate keen interest as it provides an alternative to the widely used Shuttle Radar Topography Mission (SRTM) DEM,...

In this paper we attempt to produce a first hydrodynamic model of the middle reach of the Congo river system in order to understand what controls this river’s unique bimodal flood pulse. The model covers the area between Kisangani and Kinshasa on the main stem and includes the major tributaries and the Cuvette Centrale wetland, one of the world’s l...

Hydrodynamic floodplain inundation models have been popular for many years and used extensively in engineering applications. Continental scale flood studies are now achievable using such models due to the development of terrain elevation, hydrography and river width datasets with global coverage. However, deploying flood models at any scale is time...

Forecasts of tropical cyclones have seen rapid improvements in recent years as expanding computational capacity permits more runs of finer resolution meteorological models with increasing representation of physical processes. However, the utilization of a hydrodynamic component in these models is often neglected, meaning flood forecasts typically o...

Current estimates of global flood exposure are made using datasets that distribute population counts homogenously across large lowland floodplain areas. When intersected with simulated water depths, this results in a significant mis-estimation. Here, we use new highly resolved population information to show that, in reality, humans make more ration...

In this paper we seek to understand the nature of flood spatial dependence over the conterminous United States. We extend an existing conditional multivariate statistical model to enable its application to this large and heterogenous region and apply it to a 40-year data set of ~2,400 U.S. Geological Survey gauge series records to simulate 1,000 ye...

Open-access global Digital Elevation Models (DEM) have been crucial in enabling flood studies in data-sparse areas. Poor resolution (>30 m), significant vertical errors and the fact that these DEMs are over a decade old continue to hamper our ability to accurately estimate flood hazard. The limited availability of high-accuracy DEMs dictate that da...

Flood risk, particularly in Small Island Developing States, is increasing. Although spaceborne Digital Elevation Models (DEMs) have provided a capacity to model flooding at the global scale, their relatively coarse resolution (~90 m) has led to a limited ability to provide fine-scale flood assessments in smaller catchments such as those in Small Is...

The Shuttle Radar Topography Mission has long been used as a source topographic information for flood hazard models, especially in data-sparse areas. Error corrected versions have been produced, culminating in the latest global error reduced digital elevation model (DEM)—the Multi-Error-Removed-Improved-Terrain (MERIT) DEM. This study investigates...

A poster submitted to the ESSA SSC 2018, Stockholm, regarding the preliminary method and analysis for a robust framework to represent and support the evaluation of emergent properties within complex flood hazard systems. The poster was the winner of the best poster award at the conference.

Short- to medium-range flood forecasts are central to predicting and mitigating the impact of flooding across the world. However, producing reliable forecasts and reducing forecast uncertainties remains challenging, especially in poorly gauged river basins. The growing availability of synthetic aperture radar (SAR)-derived flood image databases (e....

After the publication of our article Testing the skill of numerical hydraulic modeling to simulate spatiotemporal flooding patterns in the Logone floodplain, Cameroon’ in the Journal of Hydrology, volume 539 (2016) 265-280, we discovered an error in the simulations utilized for the paper. Specifically, a typo in an input file meant that rainfall wa...

This poster represents the latest developments of the GLOFRIM framework, including the addition of WFLOW as well as first results of a two-directional coupled set-up with PCR-GLOBWB, LISFLOOD-FP, and MODFLOW for the Niger Inland Delta.

In this chapter we review the underlying challenges that have, until recently, precluded the development of global flood models at the global scale. The solutions that have emerged in response to these challenges are presented, detailing how significant advances in recent years have enabled a shift from local to global‐scale models. Examples of cur...

The assessment of the impacts of extreme floods is important for dealing with residual risk, particularly for critical infrastructure management and for insurance purposes. Thus, modelling of the probable maximum flood (PMF) from probable maximum precipitation (PMP) by coupling hydrological and hydraulic models has gained interest in recent years....

Flood inundation models are increasingly used for a wide variety of river and coastal management applications. Nevertheless, the computational effort to run these models remains a substantial constraint on their application. In this study four developments to the LISFLOOD-FP 2D flood inundation model have been documented that: 1) refine the paralle...

The assessment of the impacts of extreme floods is important for dealing with residual risk, particularly for critical infrastructure management and for insurance purposes. Thus, modelling of the probable maximum flood (PMF) from probable maximum precipitation (PMP) by coupling hydrologic and hydraulic models has gained interest in recent years. He...

Flood modeling at global scales represents a revolution in hydraulic science and has the potential to transform decision-making and risk management in a wide variety of fields. Such modeling draws on a rich heritage of algorithm and data set development in hydraulic modeling over the last 20 years, but conceptually the challenges of global flood mo...

Conference poster summarizing the main work done so far in the project. It shows the assets and work flow of GLOFRIM, a validation of discharge simulations, and a benchmark of inundation extent simulated by two different coupled set-ups.

Current approaches for assessing large‐scale flood risks contravene the fundamental principles of the flood risk system functioning because they largely ignore basic interactions and feedbacks between atmosphere, catchments, river‐floodplain systems, and socioeconomic processes. As a consequence, risk analyses are uncertain and might be biased. How...

We here present GLOFRIM, a globally applicable computational framework for integrated hydrological–hydrodynamic modelling. GLOFRIM facilitates spatially explicit coupling of hydrodynamic and hydrologic models and caters for an ensemble of models to be coupled. It currently encompasses the global hydrological model PCR-GLOBWB as well as the hydrodyn...

To increase the representation of physical processes in inundation modelling, current research approaches aim to integrate both hydrological and hydrodynamic models. A previous study by Hoch et al. (2017) showed that spatially explicit coupling approaches can outperform stand-alone runs by single-purpose models as they combine spatially distributed...

Spaceborne digital elevation models (DEMs) are a fundamental input for many geoscience studies, but they still include nonnegligible height errors. Here we introduce a high-accuracy global DEM at 3″ resolution (~90 m at the equator) by eliminating major error components from existing DEMs. We separated absolute bias, stripe noise, speckle noise, an...

Study region: Terrain and hydrological data are scarce in many African countries. The coarse spatial resolution of freely available Shuttle Radar Topographic Mission elevation data and the absence of flow gauges on flood-prone reaches, such as the Oti River studied here, make flood inundation modelling challenging in West Africa. Study focus: A flo...

Inflow discharge and outflow stage estimates for hydraulic flood models are generally derived from river gauge data. Uncertainties in the measured inflow data and the neglect of rainfall-runoff contributions to the modelled domain downstream of the gauging locations can have a significant impact on these estimated ‘whole reach' inflows and conseque...

Synthetic Aperture Radar (SAR) data have proven to be a very useful source of information for the calibration of flood inundation models. Previous studies have focused on assigning uncertainties to SAR images in order to improve flood forecast systems (e.g. Giustarini et al. (2015) and Stephens et al. (2012)). This paper investigates whether the ti...

As modeling capabilities at regional and global scales improve, questions remain regarding the appropriate process representation required to accurately simulate multichannel river hydraulics. This study uses the hydrodynamic model LISFLOOD-FP to simulate patterns of water surface elevation (WSE), depth, and inundation extent across a ∼90 km, anabr...

Single satellite Synthetic Aperture Radar (SAR) data are now regularly used to estimate hydraulic model parameters such as channel roughness, depth and water slope. However despite channel geometry being critical to the application of hydraulic models and poorly known a priori, it is not frequently the object of calibration. This paper presents a u...

Predicting the Effects of Man-Made Fishing Canals on Floodplain Inundation – A Modelling Study

Have you ever experienced rain where it rained so hard or for so long that you feared you may soon be up to your eyeballs in water? Sadly, many people in the world have witnessed this firsthand, and this is likely to increase due to climate change unless we do something to prepare for flooding disasters. Some areas are more prone to floods than oth...

Quantifying flood hazard is an essential component of resilience planning, emergency response, and mitigation, including insurance. Traditionally undertaken at catchment and national scales, recently, efforts have intensified to estimate flood risk globally to better allow consistent and equitable decision making. Global flood hazard models are now...

Flooding is governed by the amount and timing of water spilling out of channels and moving across adjacent land, often with little warning. At global scales, flood hazard is typically inferred from streamflow, precipitation or from satellite images, yielding a largely incomplete picture. Thus, at present, the floodplain inundation variables, which...

The Surface Water and Ocean Topography (SWOT) satellite mission planned for launch in 2020 will map river elevations and inundated area globally for rivers >100 m wide. In advance of this launch, we here evaluated the possibility of estimating discharge in ungauged rivers using synthetic, daily "remote sensing" measurements derived from hydraulic m...

Recent innovations in hydraulic modeling have enabled global simulation of rivers, including simulation of their coupled wetlands and floodplains. Accurate simulations of floodplains using these approaches may imply tremendous advances in global hydrologic studies and in biogeochemical cycling. One such innovation is to explicitly treat sub-grid ch...

Accurate measurement of water surface height is key to many fields in hydrology and limnology. Satellite radar and laser altimetry have been shown to be useful means of obtaining such data where no ground gauging stations exist, and the accuracy of different satellite instruments is now reasonably well understood. Past validation studies have shown...

The topography of many floodplains in the developed world has now been surveyed with high resolution sensors such as airborne LiDAR (Light Detection and Ranging), giving accurate Digital Elevation Models (DEMs) that facilitate accurate flood inundation modelling. This is not always the case for remote rivers in developing countries. However, the ac...

Single satellite synthetic aperture radar (SAR) data are now regularly used to estimate hydraulic model parameters such as channel roughness, depth and water slope. However, despite channel geometry being critical to the application of hydraulic models and poorly known a priori, it is not frequently the object of calibration. This paper presents a...

Global flood hazard models have recently become a reality thanks to the release of open access global digital elevation models, the development of simplified and highly efficient flow algorithms, and the steady increase in computational power. In this commentary we argue that although the availability of open access global terrain data has been cri...

These computer-based practical exercises compliment the preceding chapters by allowing users to put into practice some of the ideas they have been reading about. The tasks in this chapter introduce users to numerical flood modeling using both test data and a real-life example. In Task 1 users explore the effects as well as pros and cons of includin...

This chapter provides an overview of global and low-cost topographic data to support flood studies, with a focus on usefulness of shuttle radar topography mission (SRTM) topography in supporting two-dimensional hydraulic modeling of floods. In particular, flood propagation and inundation modeling of a 10-km reach of the River Dee (United Kingdom) w...

Floods are no doubt a major hazard and the risks they pose are increasing due to shifts in meteorological forcings, population pressures, as well as anthropogenic change to riverine landscapes. Flood waves and related processes are observed globally, through either river gauging networks or remote sensing acquisitions. River gauging stations are de...

Advances in remote sensing have enabled hydraulic models to run at fine scale resolutions, producing precise flood inundation predictions. However, running models at finer resolutions increases their computational expense, reducing the feasibility of running the multiple model realisations required to undertake uncertainty analysis. Furthermore, it...

This paper investigates the challenge of representing structural differences in river channel cross-section geometry for regional to global scale river hydraulic models and the effect this can have on simulations of wave dynamics. Classically, channel geometry is defined using data, yet at larger scales the necessary information and model structure...

Floods are a natural hazard that affect communities worldwide, but to date the vast majority of flood hazard research and mapping has been undertaken by wealthy developed nations. As populations and economies have grown across the developing world, so too has demand from governments, businesses and NGOs for modelled flood hazard data in these data-...

Human populations are not static or uniformly distributed across space and time. This consideration has a notable impact on natural hazard analyses which seek to determine population exposure and risk. This paper focuses on the coupling of population and environmental models to address the effect of seasonally varying populations on exposure to flo...

Engineered floodways are floodplains managed by hydraulic controls that can be activated passively, whereby the floodway fills and empties with changes in channel stage, or through a rapid control action, such as the detonation of a levee. During May of 2011, the Birds Point-New Madrid Floodway (NMF) was activated through levee detonation and the p...

Satellite-based (e.g., Synthetic Aperture Radar [SAR]) water level observations (WLOs) of the floodplain can be sequentially assimilated into a hydrodynamic model to decrease forecast uncertainty. This has the potential to keep the forecast on track, so providing an Earth Observation (EO) based flood forecast system. However, the operational applic...

Stereo analysis of in-orbital imagery provides valuable topographic data for scientific research over planetary surfaces especially for the interpretation of potential fluvial activity. The focus of research into planetary fluvial activity has been shifting towards quantitative modeling with various spatial resolution DTMs from visual interpretatio...

Flood hazard maps at trans‐national scale have potential for a large number of applications ranging from climate change studies, reinsurance products, aid to emergency operations for major flood crisis, among others. However, at continental scales, only few products are available, due to the difficulty of retrieving large consistent data sets. More...

Recent international flood events have demonstrated the large damage and potential loss of life that flooding can cause. In order to accurately quantify flood risk and how it may change in the future, we need to improve our understanding of the uncertainties associated with making such predictions. Improvements in remote sensing have facilitated th...

In this study, we tested the application of hydraulics analysis with multiresolution martian DTMs together with 2-D LISFLOOD-FP.

Landscape evolution models (LEMs) simulate the geomorphic development of river basins over long time periods and large space scales (100s–1000s of years, 100s of km2). Due to these scales they have been developed with simple steady flow models that enable long time steps (e.g. years) to be modelled, but not shorter term hydrodynamic effects (e.g. t...

Uses the MODIS surface water product observations of the 2011 Bangkok flood.A data gap filling method is developed to better preserve the dynamics of the event.We quantify surface water connectivity geostatistically to give new flood insights.There is a clear structure to the connectivity of the event through time and space.Changes and thresholds i...

At present continental to global scale flood forecasting predicts at a point discharge, with little attention to detail and accuracy of local scale inundation predictions. Yet, inundation variables are of interest and all flood impacts are inherently local in nature. This paper proposes a large-scale flood inundation ensemble forecasting model that...

Flood simulation models and hazard maps are only as good as the underlying data against which they are calibrated and tested. However, extreme flood events are by definition rare, so the observational data of flood inundation extent are limited in both quality and quantity. The relative importance of these observational uncertainties has increased...

Flood waves moving along river systems are both a key determinant of globally important biogeochemical and ecological processes and, at particular times and particular places, a major environmental hazard. In developed countries, sophisticated observing networks and ancillary data, such as channel bathymetry and floodplain terrain, exist with which...

Effective flood risk management depends on methods for estimating flood hazard and an appraisal of the dominant uncertainties in the analysis. Typically, hydraulic models are used to simulate the extent of flooding for an estimate of the flow in a particular reach for a chosen probability of exceedance. However, this definition causes problems at r...

Satellite-based Synthetic Aperture Radar (SAR) has proved useful for obtaining information on flood extent, which, when intersected with a Digital Elevation Model (DEM) of the floodplain, provides water level observations that can be assimilated into a hydrodynamic model to decrease forecast uncertainty. With an increasing number of operational sat...

Floods are considered the most frequent natural disaster world-wide and may have serious socio economic impacts in a community. In order to accomplish flood risk mitigation, flood risk analysis and assessment are required to provide information on current or future flood hazard and risks. Hazard and risk maps involve different data, expertise and e...

There has been much interest in the use of Synthetic Aperture Radar (SAR) images to indirectly estimate flood extent and flood elevation to aid the understanding of fluvial flood inundation processes. SAR remote sensing satellites are capable of all-weather day/night observations that can discriminate between land and smooth open water surfaces ove...

Models that simulate the dynamics of river and floodplain water surface elevations over large regions have a wide range of applications including regional scale flood risk estimation and simulating wetland inundation dynamics, while potential emerging applications include estimating river discharge from level observations as part of a data assimila...

Flood inundation modelling is one of the essential steps in flood risk assessment. However, in many rivers and floodplains the desirable input data are not sufficient or unavailable. A potential opportunity to fill this gap might be offered nowadays by the global remote sensing data, which can be freely (or at low cost) obtained from internet, such...

Existing precipitation products show differences in their spatial and temporal distribution and several studies have presented how these differences influence the ability to predict hydrological responses. However, an atmospheric-hydrologic-hydraulic uncertainty cascade is seldom explored and how, importantly, input uncertainties propagate through...