E-Rise: Earliest detection of sea-level rise accelerations to inform lead time to upgrade/replace coastal flood defense infrastructure.

Lead Research Organisation: University of Southampton
Department Name: School of Ocean and Earth Science

Abstract

There is strong observational evidence that global mean sea levels are rising and the rate of rise is predicted to accelerate, significantly threatening hundreds of billions of pounds of infrastructure around the UK coast. Substantial upgrades/replacements to coastal defences will therefore be required to maintain existing flood risk management standards. However, this will involve long lead times relating to planning and implementation of schemes. For example, plans for building the Thames Barrier were started after the notorious 1953 North Sea flood, but the Barrier was not operational until 1982 - nearly 30 years later!

Rapid rates of sea-level rise will reduce the lead time available for upgrading/replacing defence infrastructure. Moreover, detecting accelerations in the rate of sea-level rise is not straightforward, due to the considerable inter-annual variability evident in sea level at regional/local scales. Our latest research has shown that it could take years to more than a decade before discernable accelerations are detected. There is therefore an immediate need to: (1) explore how quickly different sea-level accelerations can be detected, and to compare these with the lead times that are necessary for upgrading/replacing different defence infrastructure; and (2) assess whether we could detect sea level accelerations earlier, thereby extending the lead times available for action.

These issues are particular important in relation to the adaptive pathway approach for managing increasing flood risk that was pioneered in the Thames Estuary 2100 (TE2100) project. Although the essence of an adaptive management plan is its ability to adapt when needed, it will only be effective if: (1) a significant acceleration in sea-level rise is detected and then a decision is made in timely manner to move to an alternative pathway; and (2) there is an appropriate lead time to carry out the necessary adaptation. In their first interim review of the TE2100 plan, our project partners the Environment Agency have identified that they need to do much more to: (1) understand how they identify changes in sea level which significantly depart from the assumed projections; and (2) understand the lead times to put in place the flood risk management interventions.

Our proposal will apply previous NERC-funded research and other relevant research to better understand likely lead times for upgrading/replacing coastal defence infrastructure around the UK coast over the 21st century, and assess whether we could detect sea-level accelerations earlier to provide sufficient lead time for action. To do this we will develop an active partner group to discuss the issues, challenges and implications relating to detection of sea-level accelerations and the lead times. We will then develop a toolbox that will allow us to: (1) identify the timings (with uncertainties) at which accelerations in sea-level rise might first be recognized using the best possible combination of in situ and satellite-based data and most appropriate statistical methods; and (2) to estimate the lead times; for a wide range of sea-level projections. As a case study, we will use the toolbox to examine the planning and engineering implementation requirements and their associated lead times for upgrading/replacing the Thames Barrier and associated defences. The toolbox, example outputs and the guidance notes developed will be made freely available via the www.psmsl.org website, for wider use.

The study will be transformative as the outputs will allow our partners (Environment Agency, EDF Energy, HR Wallingford) and wider stakeholders to: better plan for the future by incorporating information on lead times; better monitor change; and make more effective and confident decisions as to which specific adaptive pathway to follow.

The project will last 1 year and cost (80% FEC) £118,500.

Key words: sea level acceleration, lead times, defence upgrades, Thames Barrier

Planned Impact

The impacts of this proposed project will be significant, influencing the monitoring procedures, the planning, and the management decisions of our three project partners (the Environment Agency, EDF Energy and HR Wallingford) and potentially wider stakeholder groups in the UK and internationally (e.g. iSTORM a network of storm surge barrier managers from across Europe). Our outputs will: (1) provide estimates (with uncertainty) of lead times for upgrading/replacing defence infrastructure, for a wide range of projections; and (2) facilitate better methods for monitoring sea-level accelerations. The former will improve management planning and both will allow our partners to make more effective and confident decisions, regarding when to make a change to a new adaptive pathway. Increased confidence in the trajectory of sea level rise will result in direct savings to the public purse, because: (1) it helps to ensure abortive action does not take place or over engineering of the solution, should future sea level rise turn out to be different; and, (2) it allows our partners to defer investment in to the future with confidence. This proposed work will directly contribute to address the recommendations identified by the Environment Agency in their 5-year review of the Thames Estuary 2100 plan. Outputs from our proposed study will thus feed into their more detailed 10-year review that is currently being undertaken. We expect the results to influence their current monitoring procedures and planning decisions relating to lead times, thus aiding major future decisions to move to alternative pathways (such as a new barrier) when necessary. Outcomes from this project will also influence the planning and investment decisions of our other project partners, EDF Energy, in relation to nuclear industry operations/safety measures, and HR Wallingford, who provide guidance to a wide range of clients on coastal infrastructure. As outlined in their strong support letter, EDF Energy highlight that the proposed outputs from this project are very relevant and would represents a step forward in their current practice.

The related issues of lead times and acceleration detection affect the planning and investment decisions for all coastal infrastructure and are a pre-requisite to any effective adaptively managed approach. Hence, the deliverables (i.e. the toolbox), and insight obtained from considering the case study (the Thames Barrier), have wider benefits. Since its introduction in the Thames Estuary 2100 Project, the adaptive pathways approach for managing flooding risk has been implemented in many other management plans, from large scale schemes to protect New York, through to local council schemes to protect small towns. Southampton City Council for example has implemented an approach by which new defences will be built with the capacity to be raised higher, if larger sea level rises are apparent. Yarmouth on the Isle of Wight, have also started to consider adaptive pathways approaches. The outputs from our proposed project will be made freely available at the end, with guidance, for wider use in projects like these. In the future the toolbox could be easily extended to other countries, hence there is potential for international impact.

Collectively, we have considerable experience of carrying out projects that have achieved impact. Our work on high-end sea-level rise scenarios and coastal flooding has been used to develop scenarios of extreme sea levels with DEFRA and the Health and Safety Executive and was used to brief MP's ahead of their debate on coastal flood risk on 7th July 2015. In the Sea Level SpaceWatch project we created a prototype service to support national flood defence planning with improved observations.
 
Description Detecting accelerations in the rate of sea-level rise is not straightforward. However, these forecasts are important for long-term planning for coastal infrastructure and are vital for informing adaptive planning. The aim of this project was to better understand likely lead times for upgrading/replacing coastal defence infrastructure around the UK coast and to assess whether we could detect sea-level accelerations earlier to provide sufficient lead time for action. We developed an active academic and stakeholder group to discuss the issues, challenges and implications relating to detection of sea-level accelerations and the lead times required to upgrade/replace different types of coastal defence infrastructure. We calculated rates of sea level acceleration around the UK, before and after accounting for inter-annual variability. We showed that while sea-level rise is accelerating, we have high confidence it is below the thresholds currently used for management of the Thames Estuary 2100 plan. Finally, we explored the feasibility of combining in situ and satellite-based data with statistical models to develop a toolbox which will help identify timings of future sea-level rise rates and, accordingly, to estimate lead times. This tool will help the Environment Agency to better plan for the future and implement more effective adaptive management pathways.
Exploitation Route The impact achieved in this project primarily relates to UK policy leadership. A key outcome of E-Rise is that we have developed a new innovative framework for monitoring sea-level rise accelerations and considering lead in times for upgrading coastal defense infrastructure, that is crucial for adaptive pathway approaches for managing growing flood risk. By accounting for and removing the influence of inter-annual variability in sea level records, we have been able to detect accelerations in sea-level rise earlier. We have been able to demonstrate with high confidence, by comparing current rates of rise with the projections set out in the Thames Estuary 2100 plan, that current rates are below the thresholds of the current pathway of the plan. This has significantly increased the Environment Agency's confidence that it is not yet necessary to move to alternative pathway and there is appropriate lead time required for future upgrades specific in the plan. The approach will allow the Environment Agency to better monitor change in the future, ensuring that if a significant acceleration in sea-level rise is detected a decision is made in timely manner to move to an alternative pathway. This approach is a major advancement on the sea level assessment undertaken for the 5-year review of the Thames Estuary plan, and results of E-Rise will feed directly into the 10-year review, providing a tangible measure of impact. The adaptive manage approach, pioneered in the Thames Estuary plan, is increasingly be used elsewhere in the UK and worldwide. The impact achieved in this project therefore also relates to UK competitive advantages, as flood risk management is a significant international challenge and the strategic nature of UK expertise is at a premium.
Sectors Government, Democracy and Justice

URL http://nerc.ciria.org/assets/pdf/40_Haigh%20-%20detection%20sea-level%20rise.pdf
 
Description Finds of this study have been used extensively. Between 2016-21, I worked with the Environment Agency (EA), to provide significant strategic input to the Thames Estuary 2100 Plan (TE2100). TE2100 sets out how the EA will continue to protect London, one of the world's most important coastal cities, from flooding. The EA estimate that 1.3 million people and £275 billion worth of property/infrastructure are currently at risk from tidal flooding in London. Furthermore, within the Thames tidal flood zone there are also 400 schools, 16 hospitals, 4 world heritage sites, and critical energy, transport and water infrastructure. Within the TE2100 adaptive Plan, 10 indicators of change are being monitored by the EA to assess whether they need to make key interventions (such as building a new Thames Barrier) at an earlier, or later, date. The Plan therefore requires regular formal review (with detailed reviews in 2015 and 2020). Between 2016-21, I led three studies for the EA that have directly informed the 10-year review. In 2016, I was invited to a series of meetings with the EA TE2100 team. As a direct outcome of these talks, the EA identified that they needed to do more, looking ahead to the 10-year review, to: (1) better identify changes in sea-level that significantly depart from the assumed projections; and (2) understand the lead times to enact the flood management interventions. Between 2017-18, the EA partnered with the University of Southampton on the NERC-funded E-Rise project, led by myself, which specifically explored these two issues. A key outcome of this project was the development of an innovative toolbox that has allowed the EA to carry out sensitivity testing with different rates of sea-level rise to examine how quickly different sea-level accelerations can be detected, and to compare these with the lead times necessary for upgrading defence infrastructure. Following the success of this project, I was then commissioned by the EA in 2019-20 to lead a study, which provided the evidence base for assessment of changes in the first 2 indicators (mean sea-level and extreme sea-level) in the 10-year review. In this study, we developed a significant enhanced framework for monitoring changes in mean and extreme sea-level, that utilised newly digitised long (>100 year) sea-level records from historical sources. Guided by our study and underpinning research, the EA have moved to using a higher sea-level rise projection to define timings of key intervention works. Furthermore, they have incorporated changes in tides into the TE2100 Plan, and this will be a major focus looking ahead to the 15-year review. In 2020, I was commissioned again, this time to lead a study to assess closures of the Thames Barrier, that provided the evidence base for changes in the 5th indicator (Thames Barrier operation) in the 10-year review. Here I carried out the most detailed investigation to date of how the number of barrier closures has varied in the past. I then wrote a sophisticated flexible set of software tools that estimates the number of future closures for: (1) any given sea-level rise and/or change in fluvial flow change to 2100; (2) any defined closure matrix (the water level and river discharge thresholds that determine when the Barrier is closed); and (3) any given magnitude of forecast error. Since 2018, I have been advising storm surge barriers around the world, on sea-level issues relating to our underpinning research, and was commissioned to undertake a study to guide future operation of surge barriers in the Netherlands. More than 20 large storm surge barriers (and many smaller ones) are in operation worldwide today, protecting ~30 million people and trillions of pounds of infrastructure. Following the success of the aforementioned impact-activities with the EA, I was invited in 2018 to present the results of our underpinning research at the I-STORM (an international network of storm surge barriers) annual conference. As a result, I was subsequently invited to the Netherlands in 2019 by Rijkswaterstaat (Dutch Ministry of Infrastructure and Water Management) to discuss how storm surge barrier operation may alter in the future with sea-level rise. Based on these interactions, and the aforementioned work I undertook for the Thames Barrier, the University of Southampton was formally invited to be part of the I-STORM network in early 2020; only the third university worldwide in this network. All of these initiatives above, stemmed from the E-Rise project.
Sector Government, Democracy and Justice
Impact Types Societal,Economic,Policy & public services

 
Description Thames Barrier future closure assessment
Geographic Reach National 
Policy Influence Type Gave evidence to a government review
Impact Ivan Haigh has been commissioned by the Environment Agency and Jacobs to assess future closures in the Thames Barrier with sea level rise.
 
Description Thames Estuary 10_Year Review
Geographic Reach National 
Policy Influence Type Gave evidence to a government review
Impact Ivan has recently been commissioned by the Environment Agency (£24k) to lead a sea level study that will fed directly into the Thames Estuary 2100 10-year review.
 
Description Thames Estuary 2100 - 10 year Review
Geographic Reach National 
Policy Influence Type Gave evidence to a government review
Impact Our work from E-Rise will feed into the Environment Agency's 10-year review of the Thames Estuary 2100.
 
Title Digitisation of Thames Estuary Tide Gauge records back to 1911. 
Description The Environment Agency has paid us to digitise the Thames Estuary Tide Gauge records back to 1912, and analyse these as part of the Thames Estuary 2100, 10 year review. 
Type Of Material Database/Collection of data 
Year Produced 2022 
Provided To Others? Yes  
Impact The work form this Analysis is being fed directly into the Thames Estuary 2100, 10 year review 
URL https://www.bodc.ac.uk/data/published_data_library/catalogue/10.5285/b66afb2c-cd53-7de9-e053-6c86abc...
 
Title Digitisation of Tidal Charts 
Description We have created a web-tool in R-Shiny that facilities the digitisation of tidal charts. 
Type Of Technology Webtool/Application 
Year Produced 2018 
Impact This tool will allow us to extend back in time, historic tidal records. 
 
Title Thames Barrier Future Closures PYTHON Tools 
Description In order to assess how the number of closures might change in the future with different rates of mean sea level rise and increases in fluvial flows, I developed a set of software tools. I coded these tools in such a way that estimates of the number of future closures could be flexibly returned for: (1) any given future sea level rise and/or change in fluvial flow; (2) any defined closure matrix; (3) any given magnitude of forecast error; and (4) the tool identifies years when certain numbers of closures per year exceed any given threshold (e.g., 50 or 100 closures per year). I originally coded the software tools in the MATLAB programming language, but I translated these into PYTHON as the EA does not have a MALTAB license, and PYTHON is open source and free to use. 
Type Of Technology Software 
Year Produced 2021 
Impact The tools have been used by the Environment Agency in the 10-year review of the Thames Estuary 2100 plan. 
 
Description Active partner group to discuss the issues, challenges and implications relating to detection of sea-level accelerations and the lead times required to upgrade/replace different types of coastal defence infrastructure. 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Policymakers/politicians
Results and Impact We developed an active partner group to discuss the issues, challenges and implications relating to detection of sea-level accelerations and the lead times required to upgrade/replace different types of coastal defence infrastructure. This involved the Environment Agency, EDF Energy and HR Wallingford.
Year(s) Of Engagement Activity 2017,2018
 
Description Invited speaker at iStorm Workshow 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Policymakers/politicians
Results and Impact I was invited to give a talk at the annual iStorm conference. iStorm is an International Network of Storm Surge Barriers. The I-STORM network brings together professionals that build, manage, operate and maintain Storm Surge Barriers.
Year(s) Of Engagement Activity 2018
 
Description Sinking Cities - TV Documentary 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact I will feature for 10 minutes in a TV Documentary on Channel 4 in 2018, as part of a four part series looking at mega cities and sea level rise. I feature in the London episode talking about my work on the Thames Barrier as part of the E-Rise project.
Year(s) Of Engagement Activity 2018
 
Description talk at the 2021 Annual I-Storm conference for storm surge barriers 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact I was invited to speak at the annual conference of storm surge barriers
Year(s) Of Engagement Activity 2022