Community reporter Neil Cullen lives opposite the £44 million Dawsons Corner revamp. In his latest column, he casts a whimsical eye at the latest comings and goings at the construction site.
Observant passengers travelling through the partially revamped Dawson’s Corner gyratory have noticed a huge hole excavated on the south side of the new carriageways. What is it for? Well, a clue was in the recent Connecting Leeds newsletter.
However, the arrival on Monday (8 June) of probably the largest crane ever seen in the area might have caused speculation: are the engineers having a bit of fun by installing a shark pool giving local anglers a shot at a spot of fishing with an outsize rod?
No; the answer is more exciting – or maybe to some more boring. It is a Drainage Attenuation Tank. Like many engineering products, this one will be buried for ever and never seen again. Yet it will be a vital part of the infrastructure and essential to success.
Why? We do sometimes see flash flooding in this area, when the drains are unable to cope and the roads (and sometimes gardens and even houses) get inundated. This tank aims to intercept the foul water and store it to delay its discharge to watercourses.
How much water? With the magic of Google AI, a Google Earth area calculation, and an engineer’s brain, seasoned by WLD sleuthing, we can assemble the puzzle.
Met Office records for this postcode show that a “1 in 100 years” downpour will deliver 30-35 millimetres (mm) of rain in an hour. For Climate Change we are advised to add a 40% margin, making 49 mm (2 inches). Past experience is that 50-55mm rain can fall in 6 hours, rising to 70-80 mm in 24 hours.
Google Earth says that the new areas of tarmac are 23,000 square metres. GCSE maths dictates that we should plan for 1,127 cubic metres of runoff through the drains. That is half the volume of an Olympic swimming pool. Even without access to the actual design figures, we can see that is a pretty big tank. The size of the hole south of the junction!
During the next nine weeks the hole is going to be filled with a lot of precast concrete wall segments, supplemented with some liquid concrete and all fixed together as a tank. So, for one week only the mega-crane will be on site, followed by some smaller ones.
Then it will all be buried for ever. So don’t miss the opportunity to watch the wonder. (Passengers and pedestrians only, not the drivers obviously!)
We hope to bring you progress photos during the weeks ahead. You are welcome to contribute your own if you’d like a mention in WLD. (The Editor’s decision is final).
- WLD recently reported on the next raft of road closures – die to start on Monday, 15 June – here.
- Read all of WLD‘s coverage of Dawsons Corner and Stanningley Bypass works here.
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