Barry Hankin

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Stress testing the impacts of climate change on water quality permitting across England

This presentation reports on the results of simulating 17 regulatory SIMCAT water quality models ... more This presentation reports on the results of simulating 17 regulatory SIMCAT water quality models for England based on using the CEH Future Flows dataset. The de-biased uplifts were generated across 140 flow gauges comparing 2060-2080 with 2000-2020 for 11 ensembles, and kriged across the country to capture the gradients and apply river reach-specific uplifts in headwater and along-reach flows (for mean and 95 percentile exceedance flows). The resulting uplifts were applied using a recently developed UKWIR workbook and the statistical water quality models were simulated for a range of sanitary and chemical determinands (BOD, ammonia, dissolved oxygen, total and soluble phosphorus, nitrate, PFOS, cadmium and cypermethrin) to assess the potential change to Sewage Treatment Work permits.Failure of target EQS and 10% deterioration of quality are analysed, computing the necessary adjustment to water quality permits to meet the water quality standards in the future. Ensemble uplifts repres...

Investigating ways to predict channel changes to inform flood risk management now and in the future

Science and practice for an uncertain future

Floods can cause severe and rapid changes in rivers. They can erode river banks and deposit vast ... more Floods can cause severe and rapid changes in rivers. They can erode river banks and deposit vast quantities of sediment. This can impact on land-use, infrastructure (such as bridges and culverts), and properties where flood risk is increased. Understanding these natural processes, and where they are more likely to occur, can inform risk assessment, and identify opportunities to work with nature. Approaches to identify geomorphological actitivity in rivers have been reviewed to determine which could have potential to create a nationwide assessment of river channel change in England and Wales. Two existing approaches and two novel approaches have been tested and validated against fluvial audits to determine how well they identify geomorphological activity. One of the new approaches developed though the research was used to create a national scenario library of erosion maps representing different sediment sizes, channel roughness, and rainfall probabilities. Such information could be used to plan for future change, prioritise channel maintenance activity to locations with greatest risk or opportunity, and deliver sustainable flood risk and environment management.

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Investigation of effect of logjam series for varying channel and barrier physical properties using a sparse input data 1D network model

Environmental Modelling & Software

Fuzzy rules based model for solute dispersion in an open channel dead zone

Journal of Hydroinformatics, 2002

A method has been developed to estimate turbulent dispersion based on fuzzy rules that use local ... more A method has been developed to estimate turbulent dispersion based on fuzzy rules that use local transverse velocity shears to predict turbulent velocity fluctuations. Turbulence measurements of flow around a rectangular dead zone in an open channel laboratory flume were conducted using an acoustic Doppler velocimeter (ADV) probe. The mean velocity and turbulence characteristics in and around the shear zone were analysed for different flows and geometries. Relationships between the mean transverse velocity shear and the turbulent velocity fluctuations are encapsulated in a simple set of fuzzy rules. The rules are included in a steady-state hybrid finite-volume advection–diffusion scheme to simulate the mixing of hot water in an open-channel dead zone. The fuzzy rules produce a fuzzy number for the magnitude of the average velocity fluctuation at each cell boundary. These are then combined within the finite-volume model using the single-value simulation method to give a fuzzy number ...

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Fuzzy rule-based model for contaminant transport in a natural river channel

Journal of Hydroinformatics, 2002

Fuzzy rules are used to model solute dispersion in a river dead zone, such that the turbulent dif... more Fuzzy rules are used to model solute dispersion in a river dead zone, such that the turbulent diffusion is determined by a fuzzy inference system which relates the local mean velocity shear to the longitudinal velocity fluctuations. A finite-volume hybrid scheme is applied to a non-orthogonal grid for which a mean velocity field is produced using the computational fluid dynamics (CFD) package Telemac 2D. At each cell face fuzzy rules predict a fuzzy number, and these numbers reflect the possible magnitudes of turbulent velocity fluctuations. These are input to the finite-volume model using a single-value simulation method. Multiple model runs produce a fuzzy number for the solute concentration in each cell. The results of the fuzzy model are then compared with data collected in a field experiment with rhodamine dye in the River Severn.

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07 - D Evelopment of the Surface Water Flood Map for Northern Ireland

This paper outlines the development of the pluvial or surface water flood map for Northern Irelan... more This paper outlines the development of the pluvial or surface water flood map for Northern Ireland and focuses on the technical approach taken, the assumptions involved and the quality of the outputs. The first generation model was developed to inform the Preliminary Flood Risk Assessment as required by Article 4 of the Floods Directive (2007/60/EC). The refinement of the assumptions between the first and second generation maps is examined and in particular the characteristics of the model and impact of the rain event profile as the original approach did not incorporate an allowance for permeability, urban drainage and was based on the use of a bare-earth DTM. This resulted in conservative, broad-scale topographic driven flooding, for which the influence of buildings and other flow paths were not included. The assumptions used to build the base model are detailed as these must be understood as they directly influence the mapped outputs and therefore the application of the finished p...

JBA Trust Challenge: A Risk-based Analysis of Small Scale, Distributed,“Nature-based” Flood Risk Management Measures Deployed on River Networks

We develop a network-based model of a catchment basin that incorporates the possibility of small-... more We develop a network-based model of a catchment basin that incorporates the possibility of small-scale runoff attenuation features (‘leaky dams’) on each of the edges of the network. The model is forced by a prescribed runoff to each node and predicts the time series of discharge throughout the network. It can be used to analyse the benefit and risk associated with adding dams at specific network locations. We demonstrate the model using idealised one-dimensional and two-dimensional networks, and explore the risk of cascade failure. We discuss the formulation of an optimisation problem to decide on the best dam placements for a given catchment, and give suggestions for future directions.

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Using micro‐catchment experiments for multi‐local scale modelling of nature‐based solutions

Hydrological Processes, 2021

The Q‐natural flood management project has co‐developed with the Environment Agency 18 monitored ... more The Q‐natural flood management project has co‐developed with the Environment Agency 18 monitored micro‐catchments (~1 km2) in Cumbria, UK installing calibrated flumes aimed at quantifying the potential shift in observed flows resulting from a range of nature‐based‐solutions installed by local organizations. The small‐scale reduces the influence of variability characterizing larger catchments that would otherwise mask any such shifts, which we attempt to relate to a shift in model parameters. This paper demonstrates an approach to applying donor‐parameter‐shifts obtained from modelling two of the paired micro‐catchments to a much larger scale, in order to understand the potential for improved distributed modelling of nature‐based solutions in the form of additional tree‐planting. The models include a rainfall‐runoff model, Dynamic Topmodel, and a 2D hydrodynamic model, JFlow, permitting analysis of changes in hillslope processes and channel hydrodynamics resulting from a range of dis...

A semantic approach to enable data integration for the domain of flood risk management

Environmental Challenges, 2021

With so many things around us continuously producing and processing data, be it mobile phones, or... more With so many things around us continuously producing and processing data, be it mobile phones, or sensors attached to devices, or satellites sitting thousands of kilometres above our heads, data is becoming increasingly heterogeneous. Scientists are inevitably faced with data challenges, coined as the 4 V's of data -volume, variety, velocity and veracity. In this paper, we address the issue of data variety. The task of integrating and querying such heterogeneous data is further compounded if the data is in unstructured form. We hence propose an approach using Semantic Web and Natural Language Processing techniques to resolve the heterogeneity arising in data formats, bring together structured and unstructured data and provide a unified data model to query from disparate data sets.

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How can we plan resilient systems of nature-based mitigation measures in larger catchments for flood risk reduction now and in the future?

Water Security, 2021

There is considerable empirical evidence that using nature-based solutions to restore and enhance... more There is considerable empirical evidence that using nature-based solutions to restore and enhance hydrological processes such as infiltration, interception, floodplain re-connection and water storage, is effective at small scales for low to medium probability floods. However, the performance of systems of spatially distributed nature-based solutions at larger scales or under the more extreme flooding expected with climate change, has mainly been assessed using modelling. The mechanism by which carefully designed nature-based solutions can provide naturally adaptive pathways to divert higher flood flows into expandable areas of storage in the landscape, has been less formally investigated. This paper reports on new hydrometric data collected from one of eighteen small-scale, accurately monitored micro-catchments in Cumbria, UK, to study the effect in more detail. The micro-catchments have been set up by Lancaster Environment Centre as part of the Q-NFM project attempting to quantify changes in hydrological responses due to a range of natural flood management measures that have been installed by catchment partners. A direct-runoff 2d inundation model was setup and calibrated using accurate flow measurements upstream and downstream of new river restoration project in the Lowther catchment (2.5 km 2 ) for two large storm events (Storms Ciara and Dennis, February 2020). It was used to analyse how the storage on the floodplain can expand with flood magnitude, and can be enhanced with appropriately designed natural flood management. Model evidence was then assessed for the same mechanism in the larger UK catchments of Eddleston Water (70 km 2 ) and Culm (280 km 2 ) using the same whole-catchment direct-runoff modelling approach. For both of these large catchments the same expandable field storage is evident, and we highlight how this latent property of well-designed nature-based solutions can complement traditional strategies and provide significant economic benefits over a thirty-year appraisal period of the order of €0.7 m.

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Rethinking data‐driven decision support in flood risk management for a big data age

Journal of Flood Risk Management, 2020

Decision‐making in flood risk management is increasingly dependent on access to data, with the av... more Decision‐making in flood risk management is increasingly dependent on access to data, with the availability of data increasing dramatically in recent years. We are therefore moving towards an era of big data, with the added challenges that, in this area, data sources are highly heterogeneous, at a variety of scales, and include a mix of structured and unstructured data. The key requirement is therefore one of integration and subsequent analyses of this complex web of data. This paper examines the potential of a data‐driven approach to support decision‐making in flood risk management, with the goal of investigating a suitable software architecture and associated set of techniques to support a more data‐centric approach. The key contribution of the paper is a cloud‐based data hypercube that achieves the desired level of integration of highly complex data. This hypercube builds on innovations in cloud services for data storage, semantic enrichment and querying, and also features the us...

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Assessing the significance of wet-canopy evaporation from forests during extreme rainfall events for flood mitigation in mountainous regions of the UK

There is increased interest in the potential of tree planting to help mitigate flooding using nat... more There is increased interest in the potential of tree planting to help mitigate flooding using nature-based solutions or natural flood management. However, many publications based upon catchment studies conclude that, as flood magnitude increases, benefit from forest cover declines and is insignificant for extreme flood events. These conclusions conflict with estimates of evaporation loss from forest plot observations of gross rainfall, throughfall and stem flow. This study explores data from existing studies to assess the magnitudes of evaporation and attempts to identify the meteorological conditions under which they would be supported. This is achieved using rainfall event data collated from publications and data archives from studies undertaken in temperate environments around the world. The meteorological conditions required to drive the observed evaporation losses are explored theoretically using the Penman-Monteith equation. The results of this theoretical analysis are compared with the prevailing meteorological conditions during large and extreme rainfall events in mountainous regions of the UK to assess the likely significance of wet canopy evaporation loss. The collated dataset showed that Ewc losses between approximately 2 and 38% of gross rainfall (1.5 to 39.4 mm d-1) have been observed during large rainfall events (up to 118 mm d-1) and limited data for extreme events (> 150 mm d-1). Event data greater than 150 mm, where duration was not reported, showed similarly high percentage evaporation losses. Theoretical estimates of wet-canopy evaporation indicated that, to reproduce these high losses, relative humidity and the aerodynamic resistance for vapour transport needed to be within an envelope of approximately 90 to 97.5% and 0.5 to 2 s m-1 respectively. Surface meteorological data during large and extreme rainfall events in the UK suggest that conditions favourable for high wet-canopy evaporation are not uncommon and indicate that significant evaporation losses during large and extreme events are possible but not for all events and not at all locations. Thus the disparity with the results from catchment studies remains.

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Models of everywhere revisited: A technological perspective

Environmental Modelling & Software, 2019

The concept 'models of everywhere' was first introduced in the mid 2000s as a means of reasoning ... more The concept 'models of everywhere' was first introduced in the mid 2000s as a means of reasoning about the environmental science of a place, changing the nature of the underlying modelling process, from one in which general model structures are used to one in which modelling becomes a learning process about specific places, in particular capturing the idiosyncrasies of that place. At one level, this is a straightforward concept, but at another it is a rich multidimensional conceptual framework involving the following key dimensions: models of everywhere, models of everything and models at all times, being constantly re-evaluated against the most current evidence. This is a compelling approach with the potential to deal with epistemic uncertainties and non-linearities. However, the approach has, as yet, not been fully utilised or explored. This paper examines the concept of models of everywhere in the light of recent advances in technology. The paper argues that, when first proposed, technology was a limiting factor but now, with advances in areas such as Internet of Things, cloud computing and data analytics, many of the barriers have been alleviated. Consequently, it is timely to look again at the concept of models of everywhere in practical conditions as part of a trans-disciplinary effort to tackle the remaining research questions. The paper concludes by identifying the key elements of a research agenda that should underpin such experimentation and deployment.

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A new method, with application, for analysis of the impacts on flood risk of widely distributed enhanced hillslope storage

Hydrology and Earth System Sciences, 2018

Enhanced hillslope storage is utilised in "natural" flood management in order to retain overland ... more Enhanced hillslope storage is utilised in "natural" flood management in order to retain overland storm run-off and to reduce connectivity between fast surface flow pathways and the channel. Examples include excavated ponds, deepened or bunded accumulation areas, and gullies and ephemeral channels blocked with wooden barriers or debris dams. The performance of large, distributed networks of such measures is poorly understood. Extensive schemes can potentially retain large quantities of run-off, but there are indications that much of their effectiveness can be attributed to desynchronisation of sub-catchment flood waves. Inappropriately sited measures may therefore increase, rather than mitigate, flood risk. Fully distributed hydrodynamic models have been applied in limited studies but introduce significant computational complexity. The longer run times of such models also restrict their use for uncertainty estimation or evaluation of the many potential configurations and storm sequences that may influence the timings and magnitudes of flood waves. Here a simplified overland flow-routing module and semidistributed representation of enhanced hillslope storage is developed. It is applied to the headwaters of a large rural catchment in Cumbria, UK, where the use of an extensive network of storage features is proposed as a flood mitigation strategy. The models were run within a Monte Carlo framework against data for a 2-month period of extreme flood events that caused significant damage in areas downstream. Acceptable realisations and likelihood weightings were identified using the GLUE uncertainty estimation framework. Behavioural realisations were rerun against the catchment model modified with the addition of the hillslope storage. Three different drainage rate parameters were applied across the network of hillslope storage. The study demonstrates that schemes comprising widely distributed hillslope storage can be modelled effectively within such a reduced complexity framework. It shows the importance of drainage rates from storage features while operating through a sequence of events. We discuss limitations in the simplified representation of overland flow-routing and representation and storage, and how this could be improved using experimental evidence. We suggest ways in which features could be grouped more strategically and thus improve the performance of such schemes.

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A modelling framework for evaluation of the hydrological impacts of nature-based approaches to flood risk management, with application to in-channel interventions across a 29-km2 scale catchment in the United Kingdom

Hydrological Processes, 2017

Nature-based approaches to flood risk management are increasing in popularity. Evidence for the e... more Nature-based approaches to flood risk management are increasing in popularity. Evidence for the effectiveness at the catchment scale of such spatially-distributed, upstream measures is inconclusive, however. It also remains an open question whether, under certain conditions, the individual impacts of a collection of flood mitigation interventions could combine to produce a detrimental effect on run-off response. A modelling framework is presented for evaluation of the impacts of hillslope and in-channel natural flood management interventions. It couples an existing semi-distributed hydrological model with a new, spatially-explicit, hydraulic channel network routing model. The model is applied to assess a potential flood mitigation scheme in an agricultural catchment in North Yorkshire, U.K., comprising various configurations of a single variety of in-channel feature. The hydrological model is used to generate subsurface and surface fluxes for a flood event in 2012. The network routing model is then applied to evaluate the response to the addition of up to 59 features. Additional channel and floodplain storage of *

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Flood Risk to the Strategic Road Network in England

E3S Web of Conferences, 2016

It is vital that flood risks from multiple sources to the national Strategic Road Network are wel... more It is vital that flood risks from multiple sources to the national Strategic Road Network are well understood, to help minimise disruption, reduce risk to people and to help prioritise maintenance programmes. Highways England have undertaken research to update their current understanding of risk based on improved flood mapping, SOXV GDWD FROOHFWHG RQ IORRGLQJ µKRW VSRWV ¶ WKURXJK D FRQFHUWHG SURJUDPPH WR UHFRUG IORRGLQJ Hvents, severity and causes over the last 5 years. Building on the previous risk assessment, the roads layer was interrogated against new flood hazard data for multiple sources of flooding. The road network was divided into 100m segments in order to capture a strong spatial understanding of predicted flood risk from each source, but also summarised on a 1km scale and a management area level to aid prioritisation at varying scales. The 1 km grids were then ranked across England according to each source of flooding, and also an overall rank was derived through summing these ranks together. This was validated against GHWDLOHG VSDWLDO µKRW VSRW ¶ GDWDEDVH recorded by Highways England, based on over 12,300 records, collected over 5 years.

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An integrated statistical and hydraulic modelling approach for collective flood risk assessment

This paper presents a methodology for assessing collective flood risk based on a combination of t... more This paper presents a methodology for assessing collective flood risk based on a combination of two innovative models. The first is a multivariate statistical model for extremes of river flow or sea level, based on the conditional exceedance approach of Heffernan and Tawn (2004) and Keef et al (2009). This model is analogous to a generalised form of copula function in that it separates the joint distribution of a variable into its marginal characteristics and its dependence structure. The dependence structure is flexible in its description of the joint extremes, which has advantages for representing spatial dependence in data such as river flows. The second part of the methodology is a two-dimensional (2D) hydraulic floodplain inundation model that is applied using parallel processing technology to provide high resolution gridded flood depth data over large regions (Lamb et al., 2009). These depth grids can then be combined with a model for economic losses. We present an overview of...

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Towards Risk-Based Prediction in Real-World Applications of Complex Hydraulic Models

Applications in Environmental Hydraulics, 2005

A Risk‐Based Consenting Tool for Setting Sustainable Discharge Consents

Water and Environment Journal, 2004

ABSTRACTThis paper describes the development of a guidance tool for assessing the ability of a re... more ABSTRACTThis paper describes the development of a guidance tool for assessing the ability of a receiving watercourse to assimilate pollution from point discharges. The ‘sustainable capacity tool’uses a framework that accounts for the ‘no‐deterioration’requirement of the Water Framework. Directive, in terms of the downgrading of a river‐stretch classification and the requirement to return all rivers to ‘good ecological status’. The second requirement results in a long‐term set of river‐quality targets or objectives, and it is generally assumed that ‘good’refers to ‘A2 quality in the Scottish Environmental Protection Agency classification system. The resulting sustainable capacity is defined as the risk‐based amount of capacity that could be allocated without causing a failure of the target class and which could also result in a negative capacity if the river stretch is currently failing the target class. This is plotted as a GIS layer and is intended to form an overview of water qual...

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A new method to determine interstitial flow patterns in flume studies of sub‐aqueous gravel bedforms such as fish nests

River Research and Applications, 2006

Flume studies often seek to measure and record the interstitial flow within plane‐bed sediment bo... more Flume studies often seek to measure and record the interstitial flow within plane‐bed sediment bodies and within sediment beds with wavy surfaces, such as those typified by salmonid fish spawning nests and river‐dunes. A simple, inexpensive method is described to record and map, at discrete points, the spatial variation in interstitial flow speeds in experimental fine gravel beds. The procedure uses activated carbon granules to capture a tracer: Rhodamine WT dye. Calibration of the uptake of dye by the carbon for known interstitial flow speeds allows mapping of point flow speed data initially in the nominal x‐dimension. Using interpolation procedures available in a range of commercial ‘mapping’ software packages, the point data can be used to produce quasi two‐dimensional ‘slices’ along sampling planes within the three‐dimensional gravel bed. Similarly, three‐dimensional representations can be produced within which lines of equal current speed (‘isovels’) are interpolated such that ...

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