From the Shropshire Star -

Major work on a £1.1 million flood alleviation scheme which will help to protect almost 90 properties in Shrewsbury has now reached a critical stage, it was revealed today.

Environment Agency contractors are installing the pre-cast flood wall, which will form the flood defence along the park for the Coleham Head flood alleviation scheme this week.

The sandstone-faced concrete sections have been built off site and will be lifted into place by crane.

This major element of the flood scheme will take about three weeks to complete and will require lane closures on Coleham Head.

When the installation is finished towards the end of January, work will begin to install the demountable road crossing base.

Lane closures will also be required for about four weeks while concrete piles topped by a reinforced concrete beam on the highway are installed. When Coleham Head is at risk of flooding, this concrete beam will support demountable barriers opposite Rea Brook Terrace and adjacent to the Rea Brook itself.

Project manager Anthony Crowther said: “We will continue to do everything we possibly can to minimise disruption while we build the flood defences, but there will be lane closures on Coleham Head over the next few weeks.

“We apologise for any inconvenience caused by the work. We want people to be aware of our plans in advance so that they have an opportunity to plan their journeys.”

Work began in October and is expected to take about four months to complete.

http://www.shropshirestar.com/2008/01/dela...critical-stage/

Can I just add - why the hell are they building this over autumn and winter?!?

Do you know where the multi - storey parking is going PS?
Is it the site of the present carpark in Julian Friars?

Wasn't the NCP car park at the bottom of the Cop touted as a site for a multi-storey eyesore years ago by the Council?

Nothing to do with flood defences at Coleham Head..??

I take it you're talking about the Council's ideas for a multi-storey in the area? If so - I believe it's the Wyle Cop NCP site.

Well. if you want to be pedantic PS !

One is one side of the English Bridge and one the other.

Still a bit of a tangent, going from flood defences in Coleham Head to car parking arrangements in St Julian's Friars!

Anyway... back to the flood defences - two areas of Shrewsbury will now be protected from flooding. Frankwell and now Abbey Foregate/Coleham Head. The Gay Meadow redevelopment involves the road leading from Abbey Foregate to the back of Wakeman School (sometimes called "The Narrows") being raised and able to have flood barriers mounted. This will complete the defences around the gyratory system at Abbey Foregate/Coleham Head.

The only areas of the town which can now flood are Old Coleham/Longden Coleham, Raven Meadows, Frankwell car park, St Julian's Friars car park, and Chester Street/Cross Street/bus station. Also in extreme floods the bottom of the Cop and Smithfield Road (which would therefore still close off the English and Welsh Bridges).

I'd imagine (although in the tradition of comments on web forums, this is entirely down to my prejudice and not to anything approaching actual knowledge of the events) that it's being done so that it will be ready in time for new housing development to start on the Gay Meadow site this summer.

I'm also guessing that probably quite a few Environment Agency employees will be tearing their hair out in frustration that a frequently flooded bit of the town is being left a bit more vulnerable right in the middle of flood season, but they're having to work around funding / constraints in the availability of workers and materials.

But these flood defences do not go anywhere near the Gay Meadow! It's just along Coleham Head, from the English Bridge to Rea Bridge. :rolleyes:

And my comment about it being in winter is down to what if the river floods while construction work is on going. It would surely damage/delay it?

I read somewhere that one problem in the Abbey Foregate area is the drainage system which discharges into the rivers resulting in flood water backing up onto the streets. When the new toilets by the car park were being built didn't the builders find Victorian sewers or something which no one knew were there?

I believe that they have spent a number of years now, since the 2000 floods, dealing with the drainage in the area. There is a similar pumping system now in the Abbey Foregate area to that of Frankwell. The area behind the flood defences can now be pumped free of water as far as I'm aware.

I have heard (though not entirely sure myself) that the owners of the timber yard site just up from the Seven Stars Pub is funding some of the cost. He has permission for apartments on that site but cannot go ahead until flood defences are in place.

Don't get so stroppy PS, these flood measures will affect the Gay Meadow, the entrance is just by Wakeman School and it all floods around there.

These apartments if they go ahead are a fairly interesting contemporary design, parking below naturally and a bridge apparently across the Reabrook purely for the owners/tenants should flooding prevent access. Whether that would be needed now the flood defences are there, I'm not sure.

I think this area is getting a long overdue face-lift, the viaduct is an interesting and underplayed feature IMHO.

But these flood defences at Coleham Head are on the other side of the Rea Brook to this site. You are right - development in the Old Coleham area is restricted because of the flood problems there. But as far as I'm aware no firm plans are in place to build flood defences there yet. They would have to go along the Rea Brook, as well as protect Longden Coleham from the Severn.

I've drawn up a map to show what is going on -



The red outline is the existing and planned line of defences, which protects the land behind it. As you can see, the Gay Meadow, Wakemen School and Coleham are not protected.

The green squares mark out the two development sites in the Old Coleham area.

And then the Gay Meadow site is also outlined in green.

Perhaps a map showing contours would be more helpful PS . This would help in considering the levels of the land.

I studied fluvial geomorphology in my degree but I suspect most people could take a look at that map and tell you what will happen next :) If you stop the river flooding at Rea Bridge/English Bridge then the impact further down stream (Wakeman/Gay Meadow) is intensified as the water is forced into a narrower channel and speeds up. Flood defences at Wakeman and Gay Meadow will need to follow, and fast. I'm sure the council have thought of that though :unsure:

To my mind the more sensible solution would be to deepen the channel on the other side of English Bridge. If you look at the shape of the river - it hits a bend and the discharge from Rea Brook, both of which cause the water to slow down and therefore reduce it's capacity to carry sediment. So it drops it. This is why the area on the other side of English Bridge is so silted up. If the desiment was removed, making the channel deeper, then it could carry more water before it had to wander off through the grounds of the school.

100% correct "eatshrewsbury" - however your solutions won't happen (at least not for a long time) as

1) there's no political drive
2) there's no money available
3) the planning system still doesn't work effectively when dealing with development in and near to floodplains

Ah well! :)

That makes sense to me too. I wonder when the last time a dredger was used on the river?

Probably something ridiculous like 1678.

The weir is also a problem. It slows the speed of the water for a good mile or two behind it down to nought during most of the year. This leads to silting up of the river, making it shallower. Over the past century, since the weir was built, the riverbed has probably risen by a substantial amount. If it were lowered again - and the weir demolished or altered in some way - then the river would flow much better and have a bigger capacity.

But it all costs money and the Environment Agency are, frankly, useless. They'd worry about whatever lives on the riverbed and say that it can't be dredged.

So did I. Geographers, eh? It's not all just about colouring in.

Anyway, I'm sure you're completely right - but dredging would be an expensive business and with English Bridge and weir not likely to be moved (ever) it would only be a short-term solution. There's the question of where to dispose of the dredged material, it's probably too contaminated for simple disposal on farmland.

And dredging would really only have two benefits - it would remove the islands (which can be a bit of an eyesore, although they give the swans somewhere to nest) and would also make the river deeper and more suitable for pleasure boats (although it doesn't solve the problem, by itself, of currents created by the weir).

In terms of flooding, the benefits of a bit more channel capacity would be negligible. The major problem with that particular area is that you have two rivers joining each other just upstream, both of which have a tendency to flashy peaks of discharge. By far the best way forward for that problem is the Severn-Vyrnwy Washlands project, to store excess water upstream of Shrewsbury and allow it to be more slowly released. A more assertive land-use policy, which forbids building on Gay Meadow, wouldn't hurt either.

I think that's very unfair. It's well known how much of a funding cut the EA has held to deal with recently - in the same way as Natural England has been clobbered. Add to that the extra expenditure (but not concomitant funding increase) involved with becoming a statutory consultee on planning applications in flood-risk areas. For dredging - a scheme that has the potential to cost a fortune, but with no reduction in the flood hazard - surely the costs are greater than the benefits?

The absence of flooding in Longden Coleham is believed to be attributable to work carried out at the McCarthy and Stone site and/or the effect of Severn Trent pumping. The refurbishment of Coleham Pumping Station and the temporary pumping by Severn Trent had a significant effect and the permanent capital scheme proposed for later in the year will have long-term benefits for this area.[QUOTE]