Long term investment scenarios and an opportunity to collaborate

In December 2014 the Environment Agency published Long Term Investment Scenarios (LTIS) for flood and coastal erosion risk management in England. It sets out the future costs and benefits of managing flood and coastal erosion risk in England in a range of different scenarios. Its major achievement in long-term risk-based resource allocation is to incorporate a rigorous national economic optimisation based on an


What are the future costs and benefits of managing flood and coastal erosion risk in England?
In December 2014 the Environment Agency published Long Term Investment Scenarios (LTIS) for flood and coastal erosion risk management in England [1].It is an economic assessment of future flood and coastal erosion risk management in the period 2015 to 2065.It sets out the future costs and benefits of managing flood and coastal erosion risk in England in a range of different scenarios, to provide a guide to planning future investment.
LTIS estimates the optimal level of investment in flood and coastal erosion risk management, describing the annual average investment that would be needed to fund all work where benefits exceed costs.This optimal level of investment has been applied to a range of different scenarios to understand the potential to reduce flood risk in the long term in the context of (a) the efficiencies required to reduce and hold down costs, (b) the benefits of maintaining control over development in the floodplain, and (c) the effects of climate change.The purpose of this paper is not to duplicate the report, but to outline the strengths and limitations of the work to date and suggest a collaborative approach to addressing them.

Method of analysis
The approach taken by the LTIS analysis is to start with present day risk, based on the national flood risk assessment (NaFRA) and equivalent surface water mapping, and model changes in risk into the future.This is done by offsetting factors that increase risk (asset deterioration, climate change and development on the floodplain) with actions that reduce risk (building and maintaining defence assets, forecasting and warning, development control and incident response).Benefits of different levels of investment over the study period were identified to pinpoint the investment 'optimum'.This was then used as a baseline to test the consequences of different scenarios for climate change, development on the floodplain and future costs.

Optimising investment
Investment is optimised by assessing and adding investments in 'merit order', so those that bring the most benefit in relation to costs are added first.Returns will then gradually diminish as the next most beneficial investments are added until the annual average optimum level is reached.The national assessment is built up by aggregating modelling calculations carried out at a flood risk management 'system' (FRMS) level, where a system is defined as a collection of assets that protects a discrete area of a river catchment or the coast.
The economic principles underpinning the analysis are explained in more detail in Appendix B of the report [1].In short, the economic optimum is a concept that describes the best outcome per pound spent.To establish the annual average optimum investment level, LTIS maximises net present value (NPV), where NPV is the discounted benefits of an investment, less its discounted costs.
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Strengths of the approach
The unique strength of this approach is that, at a national level, the analysis is able to rank the costs and benefits of a large number of systems (over 3,000) and a range of different policies, in order to produce credible national scenarios that are subject to a rigorous economic optimisation.
The basis for the approach is a nationally consistent risk assessment, and other national datasets for assets, their deterioration rates and costs of renewal and replacement.
The analysis incorporates results from higher-level consideration of flood risk from surface water, and the potential to reduce the consequences of flooding through flood forecasting and warning.Additional analysis shows how options such as resilience and resistance measures for properties are cost effective in many circumstances.If more properties put these measures in place, this would help to further reduce the impacts of flooding and the associated economic damages.Other approaches which are not yet possible to evaluate within the LTIS analysis might include better land management to reduce run-off, and adapting some coastline to protect inland areas.3 What do the investment scenarios show?

Optimal investment profiles
The investment scenarios indicate that the optimal level of investment in the short term (in the first 10 years) will be around £750 to £800 million (approximately ¼950 to ¼ million) a year in present day costs.This aligns FORVHO\ ZLWK WKH JRYHUQPHQW ¶V FXUUHQW LQYHVWPHQW SODQV for the period 2015-2021, which is made up of £2.3 billion (¼ ELOOLRQ of planned capital funding from government, alongside targeted external contributions to projects, and assumes that outcomes from non-capital spend (asset maintenance, flood forecasting and warning) are maintained at present levels.
The LTIS optimum investment level is dependent on a set of assumptions underlying this 'baseline' scenario: x The cost of building defences decreases by 10% by 2021 and remains flat thereafter.x A medium rate of climate change takes place over the study period.
x Any risk caused by further development on the floodplain is mitigated at the cost of the developer and this cost is not included.Over the long-term (the 50 year period to 2065), we expect the optimal investment profile to rise from the 2020s to the 2040s to £850 to £900 million (¼ WR ¼ PLOOLRQ) a year.This is illustrated in Figure 2.There is scope to influence this profile by choosing different policies, and there may be other ways to determine how costs should be distributed over the next 50 years, so the total cost is an important reference point.Averaged over the study period, this amounts to £860 million (¼ PLOOLRQ) per year.

International comparisons
International comparisons of flood risk management governance and investment approaches demonstrate a huge diversity between countries in terms of the number and types of actors involved, partly related to the administrative structures and cultures of the countries [5].A review [6] of existing decision support tools in the field of long-term flood risk management identified 19 such tools predominately developed in Germany, The Netherlands and United Kingdom as well as some other European countries.
The closest comparison between investment planning approaches at a national level is between the United Kingdom and The Netherlands.Both countries balance economic benefits and costs with standards of protection in making decisions, but with very different emphases.Both suffered disastrous flooding in 1953, with the impacts in The Netherlands making flood risk an existential threat to the country.From 1960 onwards, the Delta Commission was instrumental in using scientific analysis to inform flood risk policy in The Netherlands.It determined levels of acceptable risk, a process which was finalised on a national scale in 1996 with the Flood Defense Act.
In 2008, a special advisory group set up by the national government to examine the challenges of the future, the (second) Delta Commission, proposed a new flood risk management approach, with protection standards based not only on cost-benefit analysis but on loss-of-life calculations as well.Whilst an assessment of economically efficient flood protection standards has been described [7], the Delta Programme 2015 [8] set out new standards for flood risk management in the Netherlands based on safety: that everyone living behind dykes and dunes in the Netherlands can count on a protection level of 10 -5 by 2050 (meaning that the probability of dying as a result of a flood is no higher than 1:100,000 a year).This contrasts with the United Kingdom where there are no target standards of protection, and government policy is to compare expected whole life benefits and whole life costs of a scheme.It is in this context that the LTIS analysis provides a powerful national tool, as it is able to optimise investment by assessing and adding investments in 'merit order', so those that bring the most benefit in relation to costs are added first.

Figure 2 .
Figure 2. Modelled long-term investment need ± annual averages over the next 5 decades (costs in present day terms).