The Deep – Hull’s Aquarium on the Humber.  Picture Credit: Image by MussM from Pixabay

How can you protect a city from flooding while reducing congestion and creating 19,000 jobs? Hull has an idea, and it might surprise you. Their answer is, to build a lagoon.

Lagoon Hull, as the proposed flood defence scheme is known, is an ambitious engineering project, designed to shelter the city but also to create a road that allows traffic to bypass the busy urban streets. Looking likely to cost around £1.5 billion, the proposal suggests building a six-mile wall in the Humber estuary, thereby creating a calm water lagoon.

Computer modelling – conducted by two independent teams – has demonstrated that adding this wall should make the water levels lower, rather than higher. This is due to the complex estuarine conditions. A four-lane road on top of the wall will keep through traffic away from the congested city centre, and a new outer harbour will benefit the growing offshore energy sector in the region.

Huge lock gates will let boats in and out, and the lagoon will give life to a new waterside area that project manager and civil engineer, Paul Hatley, believes will help to create up to 19,000 jobs.

Historically, the city of Kingston upon Hull (abbreviated to Hull) hasn’t been shy to invest in engineering. Readers with a keen memory might remember that I visited back in 2017 – when it was the City of Culture – to stroll along the 2,220-metre suspension bridge while listening to an auditory art installation.

Between the bridge (the longest single-span suspension bridge in the UK) and the power stations, oil refineries and wind turbine factories along the banks of the Humber estuary, there are plenty of engineering feats to go round.

It’s possible that the proposed lagoon is little more than fantasy right now. It seems likely that Covid-19 and the recession that follows will mean that projects like this are not a priority.

However, it’s an interesting scheme, with some major benefits for the city at a time when additional jobs would be welcome. And, of course, the last thing Hull needs right now is a flood.

Ninety percent of the city has been built below the level of the mean high water spring tide high-tide so it’s particularly vulnerable to flooding. Despite an existing flood barrier, when a record tidal surge occurred in December 2013 the city did suffer some significant flooding (although thousands of additional properties were protected by the barrier).

There have been some improvements to flood defences since then, but it’s clear that the lagoon would give the city greater peace of mind. Researchers at the University of Hull carried out a simulation showing that if the same tidal surge hit the city in 2108, when sea levels are expected to have risen by one metre, the lagoon would offer Hull 100 per cent protection. And the rest of the estuary would see a 33 per cent reduction in flood volume.

It will be interesting to see whether this innovative proposal gets the go ahead in the next few years.

Meanwhile, if you need assistance with the structural elements of an upcoming project, please do get in touch.