Comments on: Former Environment Agency manager says ‘we can’t engineer our way out’ of flooding from climate breakdown https://www.newcivilengineer.com/latest/former-environment-agency-manager-says-we-cant-engineer-our-way-out-of-flooding-from-climate-breakdown-09-01-2024/ Civil engineering and construction news and jobs from New Civil Engineer Fri, 12 Jan 2024 17:42:23 +0000 hourly 1 https://wordpress.org/?v=6.0 https://www.newcivilengineer.com/wp-content/themes/mbm-mops-2017/images/logo.gif New Civil Engineer https://www.newcivilengineer.com 125 75 Civil engineering and construction news and jobs from New Civil Engineer By: Roger Falconer https://www.newcivilengineer.com/latest/former-environment-agency-manager-says-we-cant-engineer-our-way-out-of-flooding-from-climate-breakdown-09-01-2024/#comment-4607 Thu, 11 Jan 2024 07:42:56 +0000 https://www.newcivilengineer.com/?p=272585#comment-4607 In reply to jgcanton@googlemail.com.qsi.

Thanks Derek, you cite another interesting example. My fundamental problem is the headline that ‘we can’t engineer our way out’ of flooding. Engineers put a man on the moon over 50 years ago, and I could cite many other remarkable engineering achievements over the centuries. I do not accept the view that engineers cannot solve the flooding challenges. I believe that by comparison with many other engineering challenges over time, the risk of flooding can be significantly reduced. We just need more support from the stakeholder community to enable engineers to get on with the challenge of designing what’s necessary to reduce flood risk.

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By: nigel.scott@blueyonder.co.uk.qsi https://www.newcivilengineer.com/latest/former-environment-agency-manager-says-we-cant-engineer-our-way-out-of-flooding-from-climate-breakdown-09-01-2024/#comment-4606 Wed, 10 Jan 2024 13:20:18 +0000 https://www.newcivilengineer.com/?p=272585#comment-4606 I would also draw readers attention to the Banbury Flood Alleviation Scheme which is similar to the Skipton Scheme but uses innovative passive control of the river channel flows by double-baffle orifices as described in this paper: https://britishdams.org/2012conf/papers/6 Construction – new dams and upgrades/Papers/6.5 Ackers – The design and construction of Banbury flood storage reservoir.pdf

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By: derek.stewartsmith2@btopenworld.com.qsi https://www.newcivilengineer.com/latest/former-environment-agency-manager-says-we-cant-engineer-our-way-out-of-flooding-from-climate-breakdown-09-01-2024/#comment-4605 Wed, 10 Jan 2024 11:13:49 +0000 https://www.newcivilengineer.com/?p=272585#comment-4605 In reply to Roger Falconer.

I agree with Roger. There was a new housing development constructed in the 80’s at Sudbury where the local stream would have been overloaded by the intense run off from the new estate.
A small slotted dam was incorporated in the local stream to restrict the down stream flows
The peak flows were stored locally on open ground forming part of the estate.
All landowners with streams that feed into local rivers must be encouraged to construct storage reservoirs on their land to store valuable surface water on a similar basis.
Farmers in particular would benefit during the summer months with a valuable source of water for growing their crops during the long dry spells which are happening with climate change.
Grant aid provided for such schemes would be a more effective way of reducing the down stream floods in towns than expensive bank raising
If this could be done in the 80s why can’t it be done now?

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By: jgcanton@googlemail.com.qsi https://www.newcivilengineer.com/latest/former-environment-agency-manager-says-we-cant-engineer-our-way-out-of-flooding-from-climate-breakdown-09-01-2024/#comment-4604 Wed, 10 Jan 2024 09:00:42 +0000 https://www.newcivilengineer.com/?p=272585#comment-4604 MET office CP18 updated in 2022 says as an example :3.2.6 UKCP Local (2.2km) suggests significant increases in hourly precipitation extremes in the future. For example, rainfall associated with an event that occurs typically once every 2 years increases by 29% (central estimate). This has several implications for how we manage water. It is worth noting that whilst the intensity of hourly rainfall is projected to increase in the future, overall summers are projected to become drier.
I suggest that the detail of these projections should be reported and made more widely available both to the engineering community and the public. If typically a 1 in 2 year event ( perhaps better expressed as 50%probability in any one year) is projected to deliver nearly 30% more rain ( ie water if on a saturated catchment), then it would be clear to all that it is not possible to engineer one’s way out of such a dramatic increase in “loading “. Wider understanding of CP 18 might lead to better responses as would wider understanding of IPCC SR18. We have known this detail for at least 5 yrs now, but obviously not communicated it effectively

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By: Roger Falconer https://www.newcivilengineer.com/latest/former-environment-agency-manager-says-we-cant-engineer-our-way-out-of-flooding-from-climate-breakdown-09-01-2024/#comment-4603 Wed, 10 Jan 2024 07:54:50 +0000 https://www.newcivilengineer.com/?p=272585#comment-4603 I would questions whether focusing defences for certain towns along river reaches is the ideal solution for managing flood risk and I would like to comment on the statement: “We can’t engineer our way out. Raising existing defences won’t be technically, financially or environmentally possible”. In my view part of our problem in trying to address flooding in the past has been to focus on protecting properties in particular towns and not fundamentally addressing the key problem of holding the water back upstream and in the upper catchments of the river basin. In my view we need a systems-based approach to addressing flood risk for the whole river basin from the upper catchments to the coast and not specifically focusing on flood defences for any particular town or region. Whilst I support the basis of nature-based solutions, the impact is often small in reducing peak levels downstream (typically ca. 5-10%). In contrast, with modelling of the complete river basin from catchment to coast, ideal sites could be identified for relatively small dams (typically 10-20 m in height), which would be built solely to hold the water back in the upper reaches of the river basin. The dam would have a culvert to allow some water through during floods, but impound much of the water during the storm, then releasing the water as the storm recedes and emptying the dam in advance of any subsequent flood shortly after. The flood mitigation dams built around the town of Skipton, provide an excellent example in my view as to how engineers can best deal with increased flood risk in the future. Some details of the Skipton Flood Alleviation scheme are illustrated here: https://www.gov.uk/government/news/skipton-flood-alleviation-scheme-officially-opened

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