Modelling nature-based solutions for alleviating flood risk

Ambiental Technical Solutions Ltd

By Paul Drury

Ambiental has formed a new partnership with Viridian Logic, who showcased the capabilities of their new offering to NAIAD in July this year. Our unique modelling solution can prioritise which nature-based solutions are the most suitable to create and where best to situate them.

Working with nature, rather than battling to hold it back is becoming more widely recognised as a pragmatic, and cost effective approach to flood risk management, which often has the added benefit of enriching ecosystems, improving aesthetics and enhancing amenity value. Whilst hard engineering will always have a key role in urban drainage design it is possible to use natural processes to augment and sometimes replace traditional methods.

The challenge with using Nature-Based Solutions (NBS) has up until now been the difficulty in assessing and modelling their positive impacts and knowing where best to situate them. The joint Viridian/Ambiental approach aims to identify ways to reduce flooding as efficiently as possible and then quantify the benefits that the various options will deliver. This is particularly salient in the case of projects such as NAIAD, which look to create real, natural solutions to flooding that can also deliver co-benefits. The NAIAD initiative involves researchers from all over Europe and is looking to create replicable methods of delivering nature-based solutions, as well as increasing academic understanding on its planning, policy and finance.

NAIAD 2020 nature insurance value: Assessment and demonstration

Ambiental/Viridian were invited to present their modelling approach to the NAIAD community at Montpellier, in the south of France last month. The week of workshops focused on the nine demonstration projects of NAIAD, with researchers learning about work as diverse as Spiritual Values and Financial Valuation. Viridian’s Angus Middleton presented on the offering and shared a platform with Nicolas Bauduceau of CCR, Roland Nussbaum of MRN and Charles Dumartinet of COVEA to explore the theme ‘Green Protective Measures: towards a new paradigm for insurance.’

From the workshops it was established that there is a tremendous amount of excellent research happening on nature-based solutions right across Europe. There is also a slow awakening to the fact that Geographic Information Systems (GIS) alone is not a good tool for planning natural solutions to water-related risks such as flooding. The Ambiental/Viridian offering, combined with Ambiental’s range of flood risk management tools, determines the optimum solutions for reducing flood damage, minimising the cost of defences and maximising additional benefits. This was of particular relevance to the insurance industry in France where there is an emphasis on using NBS as a way of reducing premiums associated with insuring public assets and natural capital.

Viridian's prioritisation modelling

An extract from Viridian‘s prioritisation modelling, highlighting where to create wetlands and woodland to reduce flooding, diffuse pollution and erosion.

New rigour in planning nature-based solutions

There is huge interest in using NBS to reduce flooding (also known as ecosystem services and natural flood management), since it can be low-cost, resilient to climate change and offer a host of other benefits to people as well as wildlife. Traditionally, the design of these natural systems has been informed by map analysis within GIS. However, evidence is building that just using GIS methods can design inappropriate solutions, and potentially site them in the wrong places. Viridian has solved this problem by amalgamating GIS and hydrology into a single modelling system, which can determine which natural solutions to create and where best to create them in order to reduce flooding most effectively.

The joint offering delivered through this partnership is now available through Ambiental. It outputs a detailed ranking of all potential NBS solutions across a catchment, assessing how effective they will be within local constraints. These feed perfectly into Ambiental models for flood quantification, so the reduction in flood risk (or damage from flooding) achieved by any combination of the ranked solutions can be calculated with commendable precision. This unique capability helps bring together new and innovative natural flood mitigation approaches with the traditional, engineered flood protection methods. Furthermore, it can identify co-benefits such as improving water quality and connecting disparate habitats, which in turn helps with scheme acceptance and potentially unlocks alternative funding streams.

In combination with the well-established Detailed Drainage Design and Sustainable Urban Drainage Systems (SuD) services available from Ambiental Environmental Assessment it is felt that this new capability further unlocks the potential for using natural solutions for mitigating flood risk as well as improving environmental performance in land use planning and development activities. For more information, contact us.

The author wishes to acknowledge the contributions of Angus Middleton from Viridian Logic for his input towards the formation of this article.

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