Excessive rain during October 2012 that fell on a saturated river catchment. October is usually Wales' wettest month (unlike in 2015). 2012 was especially sodden. Land high above Rhuthun/Ruthin that fed tributaries of the Afon Clwyd River was soaked and water tables were full. Over the weekend of November 24-26 and particularly early on November 27th came more significant, prolonged and heavy rainfall (three inches in 24 hours) that water tables simply could not contain. The Clwyd flooded.
What happened to the Glasdir defences?
The defences comprising a well elevated bridge, a perimeter bund and under-road reservoir with culverts were built before the estate. These were at a cost of £3mil. These were supposedly constructed to withstand a once-in-a-thousand-year flood event (November 2015's was subsequently assessed at a one in 200-300 year event). The immediate cause of the breach of defences was blocked culverts. These were up to 95 per cent chocked, by vegetation and by debris either brought down by high waters or having accumulated over some time—the official report did not know which. It it been the latter then it was possible a public authority might have been culpable. The report stated that as small an item as a single branch could cause devastating flooding. This resulted in a damming effect that caused water to back up on the "wrong" (i.e. estate) side of the culverts. Gradients downstream of the culverts were insufficient to allow water to escape naturally. Once in, the defences prevented the water getting out. There was reportedly insufficient maintenance of the culverts & grills. The grills covering the culverts were also believed to be of a sub-standard design. The grills were fitted to keep trespassers, especially children, out but have subsequently been removed.
Who was responsible for the culverts?
It was initially believed that this was the county council when actually any design fault and maintenance issues may be the responsibility of the defences commissioner and builder. The highways authority put up the case that it was responsible for the road but not what was beneath it, certainly not to the depth of the under-road culverts. The culverts and the bunds were built by the now defunct Welsh Development Agency. In 2006, the WDA was absorbed by the Welsh government. There is a case, therefore, that the government was responsible for both the design and maintenance of the culverts but that will depend upon how the Courts interpret matters. At an early public meeting, Glasdir residents reported that the council's chief executive admitted liability (we cannot corroborate this). Home-owners at Glasdir are already believed to be suing the county council for up to £4½mil. This could reach much more if trauma is considered.
Why might it be the government rather than the council?
The argument goes that the government owned the land and still does, under the road. As landowner, it may have riparian responsibility—a duty of care to ensure that the water passing through land under its control does no damage. Upstream of the government's land, the developer itself may also have riparian responsibility. If the land was the government's and all the council did was adopt the highway over it, this is a matter for Cardiff Bay and not County Hall. This will probably need testing in the Courts. The adoption process was rushed because the government wanted it done quickly to facilitate development of the area—and to bank the estimated £7½mil for the land. The developer would not begin till he was content that the highway was adopted because of possible liabilities and all this put pressure on the adoption process.
Were houses built to the correct height specification?
It seems not. Residents discovered plans that suggested in some cases the slab heights should have been about 22in or nearly 2ft higher than they were. Building these houses at what residents argued was the correct slab height might have prevented some—most?—of the 2012 flooding. It would not have stopped all of it, as some houses were 3ft deep or more in water, during the peak of the flooding. The issue appears to be about which flood model the landowner and developer assumed to be correct: we understand that one suggested housing should be raised further than it was but another did not. Much of the pavement/cycle path and road is, of course, super-elevated.
What went wrong regarding the slab heights?
If you assume that the builders understood the implications of the flood modelling, it might be that the developer did not build them correctly. Residents argue that Taylor Wimpey, in knowing that their houses were on a flood plain, was negligent. Given their location, residents believe that the planning/building control regulator, the county council, should have ensured that the houses were erected in accordance with the proper plans. These days, building control is more of a "light-touch" regulator, relying on the honesty of builders. According to the BBC, the council cannot prove that it checked slab heights or not. But the council stated that the levels met the Environment Agency's minimum requirements.
How many homes were flooded?
At the time of the flood, Taylor Wimpey had built some 150 homes of a total of 230 for which permission was granted. 122 homes were flooded. Some of the homes were, of course, flats above the ground floor.
Why was there initially little help on site?
Residents complained they were very much on their own and had it not been for the postman or men would have received no early help at all. Postal staff played a pivotal part in alerting residents to the pending disaster and in helping them move possessions. Police and fire & rescue services were focusing on a known risk at Llanelwy/St Asaph which, of course, was equally hit and indeed claimed the life of an elderly woman. There was a belief that Glasdir was sufficiently guarded against flooding.
Was it wise to build on these wet fields?
In hindsight, no. Locals knew that the area had always been prone to usually gentle flooding. There have been times when grazing stock in the area have needed to migrate to elevated land. Raised valves and pipe chambers in the vicinity of Glasditr offer a clue as to the potential for flooding. But, it's easy land on which to build and it's on the fringe of Rhuthun. With pressure to build more housing, it isn't so simple to identify areas where towns such as Rhuthun can otherwise expand. The land itself was publicly owned, having passed from the council to the WDA: this was one less impediment. With the proper mitigation, it was theoretically possible to develop the area. Taylor Wimpey bought the land in 2007 in good faith, accepting that the flood defencesas installed would work.
What assurances did residents receive?
Property owners were convinced by the seller, Taylor Wimpey, that the houses were safe from flooding. When selling, Taylor Wimpey acknowledged that there had been an issue in the area. It provided a sheet of paper that attempted to, indeed did, reassure purchasers that the measures put in place (by the WDA) would be robust to counter the likes of the 2012 flooding event. Taylor Wimpey's sales pack included two technical maps showing likely flood levels before and after mitigation. These reassurances were given by sales assistants. The blog author had previously discussed this with one of them and been given the same guarantee. It's possible that in translation Taylor Wimpey meant that the defences would withstand a one-in-a-thousand event into a one-in-a-thousand-year flood but, even so, after the flooding, residents countered that their homes were mis-sold.
What has happened subsequently?
During 2015, the county council strengthened the flood defence works around Glasdir. This raised the defences at one end by 3½ft and at the other by ½ft, to withstand a 1:1,000 year event. This was to the tune of £263,452, paid for in equal parts by the council, the developer and the government. Apart from completing at least one home that at the time of the flood was almost ready, the site has stood idle since the flood. That home was the only one sold after November 2012. Subsequently, two houses appeared for sale in September 2015 that were marketed as brand new. These were completed before the flooding but were unsold beforehand.
Are the defences enough and will the developer recommence building?
About a dozen homes in various states need finishing. Another 60 were due for building. The proof will be in whether the developer feels happy to recommence building. If the commercial mortgage and insurance market is content that there are proper & long-lasting forward maintenance procedures & guarantees in place for the strengthened defence work then it just may be that the remainder of the incomplete houses can be finished.
Is there any value left in Glasdir homes?
As one resident said in the media at the time, "No one in their right mind would want to buy a property here now. It’s mostly young families and first-time buyers on this estate, and their homes are worthless". Yet, some houses have subsequently sold , although it's been a long and arduous process for those on the market or who wish to get out. Sale prices are as reasonable as they were when new. Some say that passing the three year mark will result in a change to commercial mortgages being available again. This is apocryphal. The difference will be the strengthened defences coupled with an assurance that they will be maintained (see above).
Glasdir bore the brunt but it wasn't the only part of town that was flooded