The Thames in flood

[Kit Davies]

For those who may need it, here is a link to the Environment Agency's
very useful live map showing flood warnings and alerts currently in place:

http://www.environment-agency.gov.uk/homeandleisure/floods/142151.aspx

Unfortunately I can't link to specific geographic locations on the map,
but zooming in on the Thames, the effect of the Millenium river is
stark: a completely alert-free zone in an otherwise unbroken line of red.

Kit

[Carl]

That map loses its flood-zone markings when at its highest
magnification, so click one down in scale and the floodable zones
appear. Don't ask why, but while the most useful data (to riparians &
users of the river) are somewhere in that website it's a beast to navigate.

Those affected by the non-tidal R Thames can get to individual
locations, with graphs of levels for the last 48 hours, from here:
http://www.environment-agency.gov.uk/homeandleisure/floods/riverlevels/120580.aspx?RegionId=9&AreaId=25&CatchmentId=157
Click on a lock or a location in the right-hand column & you get the
relevant measuring station. Where it's a lock, you can read both
upstream & downstream levels.

I think in your ire you may have meant to refer to the Jubilee River,
Kit? That's the channel dug ineptly & at huge cost past Dorney which
opened just in time to cause flood havoc in 2003 everywhere _below_ the
point at which it rejoins the main river, below Windsor.

This excavation was purely political. Unchecked building of houses,
roads & other hard surfaces & installations on the Marlow/Maidenhead
flood plain had created a serious flood hazard for the generally
influentual & not particularly impoverished occupants of that new
housing, & for those in older housing nearby. These folk carried
political clout, so the taxpayer was inveigled into spending �5m on a
poorly-specified, poorly-built channel, which then required costly
re-working & litigation ending up in a �2.75m partial settlement. Good
management does not get into such a fix.

But the key is in that term 'flood plain'. Any hydrologist knows that
after exceptional precipitation rivers occasionally over-fill & can't
then flow fast enough to drain their catchments, so they need expanses
of flattish fields over which to store that excess water for a few days
- the flood plains. Build houses on those areas & anyone with a brain
will tell you to expect nice designer kitchens to get wet to counter
level from time to time. So best you build on stilts, leaving floodable
land open below you, or build elsewhere. But that's too obvious &
people like to assume it can't happen to them.

So they got lobbying & this channel got dug - to much increase the
throughput capacity of the existing river across & from this flood
plain, so it could flush away the water rather than have it accumulate
where it had always accumulated & spoil all their costly new carpets.
But there was a snag, which "any Fule would kno" - the poor sods living
further downstream would then have much more water hosing past them.

Channels only pass more flow by getting deeper & the water surfaces
becoming more steeply sloped. The folk downriver stayed dry because
their banks were never subjected to the sudden flushing away of waters
which previously had been temporarily stored over that now bypassed
flood plain. When the Jubilee River opened, that following winter far
more water than might otherwise have been expected after heavy rainfall
came rushing down narrow reaches unfit to pass such volumes - with
widespread flooding where it'd never otherwise have occurred.

The Environment Agency had not anticipated this. Their river models
were hopelessly deficient and they hadn't a clue what would happen from
hour to hour. Like yo-yos their predictions oscillated from high to low
& back again - less use than a chocolate teapot. There was mayhem, and
for some there was ruination. And the resulting increased flood risk
for these downstream inhabitants, generally less affluent than those
living on the nicely-drained flood plain upstream, hit their house
values & made insurance more expensive or impossible to renew.

The final insult came months later, when the EA held a series of "flood
meetings". Residents & business owners who attended, usually in local
schools, found themselves confronted by burly bouncers at the doors and,
once inside, subject to specious flannel from non-technical apparatchiks
about the wonders of the river management, while the actual technical
experts were watched like hawks by the same managers lest they relax &
talk real technicalities.

I'd just got into such a discussion with a couple of EA engineers (as a
former Chemical Engineer I know a bit about de-bottlenecking of process
plant) & was asking where ideally they'd start de-bottlenecking a river
system: at the top, the middle or the lower reaches? They'd just agreed
that starting in the middle (the Jubilee River) was a crap idea when
their ignoramus manager stepped in & broke up our discussion.

As Kit notes, while folk downstream are again being flooded (and it's so
often the poor, the elderly & the infirm), it's not hurting those on
that former flood plain which, yet again (& it was the same last winter)
is being assiduously drained so it pours into the homes & businesses
further downstream from a narrow river which can't handle such flows
without spilling.

While our government is falsely claiming to be increasing flood defence
spending, the most competent flood protection engineers in the EA are
being encouraged to quit so's HMG can make what they ludicrously like to
call "efficiencies". In such a process it's always the best of the
bunch who jump first, so wise heads should buy shares in makers of
thigh-waders.

Carl

--
Carl Douglas Racing Shells -
Fine Small-Boats/AeRoWing Low-drag Riggers/Advanced Accessories
Write: Harris Boatyard, Laleham Reach, Chertsey KT16 8RP, UK
Find: tinyurl.com/2tqujf
Email: ca...@carldouglasrowing.com Tel: +44(0)1932-570946 Fax: -563682
URLs: carldouglasrowing.com & now on Facebook @ CarlDouglasRacingShells

[Kit Davies]

On 08/01/2014 00:50, Carl wrote:
> I think in your ire you may have meant to refer to the Jubilee River, Kit?

Oops. I did.

The river level at Walton broke the record at 8am this morning. You can
see it for yourself here:

http://www.camvista.com/player/walton/

Goodbye rowing & sculling for the foreseeable future :(

Kit

[thomas....@googlemail.com]

At the other end of the Jubilee river we've got some prety serious flooding here areound Henley and Madienhead as well, currently in Henley its possible to scull on the Boat Tent field and Steward Enclosures its got that deep

[Carl]

Currently the upstream gauge at Chertsey Lock shows at just 3cm below
the maximum it has recorded (since 1985) - which I guess would be
January 2003 (but the EA doesn't tell you that). On the link I gave
last night you'll see a daft flaw in their graphic - the label saying
"Highest recorded" obliterates the last 12 hours of the plot. Style
wins over content, as ever.

This morning we had an automated telephone message from the EA
predicting flooding for this afternoon. Strange,, as we we thought we
had flooding already...... And they're talking now of levels higher
than in January 2003 - the year after the Jubilee River opened.

But the EA is happy to send floods to those downstream of their Jubilee
ditch - rather close it & let the oncoming waters cover that crucial,
historic flood plain and its recently installed occupants.

There are other issues: the EA decided a decade or so ago to nolonger
dredge the non-tidal Thames. But managed rivers running between narrow
banks inevitably accumulate deposits of silt & gravel which can markedly
reduce their flow capacity. When you don't dredge, at times of high
flow the river responds the only way it can, by rising higher & flooding
the surrounding land, roads, housing - it's maths, not magic.

Similarly, the tidal Thames is no longer dredged. So the tideway runs a
bit higher too. And sea levels are also rising. To deal with this, the
river walls are built up in London. Yet the Thames Barrier, which
blocks incoming tidal surges to protect London, has closed twice on each
of the last 6 days to prevent a catastrophic inundation of the centre of
the capital. This increasingly marginal situation will end in tears one
day.

Locally, several local roads & one main river crossing are now closed by
floods, & it'll get worse. What is this costing businesses? I'd guess
far more than regularly dredging the river bed, AKA proper maintenance.
But, for a slick departmental "saving", reason goes out of the window.

What we don't need next is a smug Prime Minister & his sycophantic trail
of spin doctors, PA's, council officers & cops descending for further of
the "victim tourism" they inflicted a few days back on the village of
Yalding, Kent - flooded since Xmas but until that day ignored by all
those well-paid to look after their interests.

Must Parliament be flooded to terminate the folly of so much
governmental short-termism? Must we see a flood equivalent of the Great
Stink of the 1850s, which so stirred Parliament to address the
inadequacy of London's drainage? Better to deal with the increasing
flood vulnerability across the UK before spending those many & flexible
billions on a future high-speed train track to get holders of expensive
tickets from London to (not quite) Birmingham just a few minutes faster.

[Carl]

Interestingly, an even larger Thames Valley flood scenario was the
subject of a Lloyds of London exercise begun in 2009:

http://www.lloyds.com/~/media/Lloyds/Reports/Top%20100%20PDFs/2009RDSScenarioSpecification_v13_Compressed.pdf

- go to page 47 and not the similarities with current events in this region.

Perhaps insurers are a whole lot more switched on than those we elect.

[Carl]

On 08/01/2014 15:06, thomas....@googlemail.com wrote:

FWIW, we now have >5cm of water across our workshop ground floor, but we
are promised more over next day or so. What fun.

But we are still working, to a somewhat modified production plan. And
all movable stuff is lifted above the floods - within the limits of what
can be done. We are still building boats & still preparing & shipping
parts orders (maybe shipping was never a more appropriate term?). It
takes more than a bit of water to faze real rowers.

As for Maidenhead area: I see that water levels at Taplow are
spectacularly low, & it's not that high just below Boulters Lock - all
thanks to the "Luverly Jubbly river" being wide open for the special
benefit of M'head flood plain occupants & the wider detriment of those
downstream. Meanwhile, the poor folk around here are being moved out of
their drowned homes, yet again!

Care to swap? The last 11 years have seen more flooding around here
than in any similar period in the past. The Jubilee River has been in
operation for the last 11 years.

[magnus....@gmail.com]

I looked at the EA link for Sunbury Lock, and it's showing the "recent high" was 0.73 metres on 27/12/12, i.e. last year. It's showing current level at 0.69m.
I live very close to Sunbury Lock, and I have photographs I took on 27/12/12 while walking on Rivermead Island which is just next to that Lock.
Rivermead Island is now completely underwater, it's just a big lake-extension to the river, so I'm afraid the values on their website for Sunbury lock at least are nonsense.

[Carl]

It is depressing that the fine and concerned Thames Conservancy, which
created the river as we came to know it, & which was a couple of decades
ago or so downgraded to a state of supposedly benign neglect under the
former National Rivers Authority, is now merely a dysfunctional folder
on the shelves of the so-called Environment Agency.

The EA by turn is seen as merely an inconvenient pustule on the backside
of Defra, that government acronym to which it answers, fit only to be
starved & squeezed in the name of "economies" by a cabinet composed of
affluent folk with dry feet who, mostly, have never struggled with real
work or the adverse consequences of their own folly.

No, I don't believe those data points either.

But, for those decent people with water now lapping over their feet (or
knees) & wrecking their homes & livelihoods, it's all the rest of the
world has to go by. Note that I didn't use the term 'hardworking' to
describe these victims since it has become the hackneyed & devalued
description used by government ministers when about to viciously
marginalise another sector of the community while patronising the rest
of us.

If you don't dredge & maintain your rivers, if you don't control
flood-plain construction, if you do stupid things to suck up to noisy
sectors of the community, then expect trouble. And that's what we've got.

[magnus....@gmail.com]

my mistake. there is a "downstream station information" button on the same page which when pressed gives the level just downstream of the lock, as opposed to upstream, and makes a little more sense by indicatig level about a foot higher than last year.

[Sarah Harbour]

Just seen this picture posted on Twitter: https://pbs.twimg.com/media/BdjAd8OIMAACYYS.jpg:large

It's a car floating past Leander Club... :s

Stay safe everyone,
Sarah

[stew...@gmail.com]

> my mistake. there is a "downstream station information" button on the same page which when pressed gives the level just downstream of the lock, as opposed to upstream, and makes a little more sense by indicating level about a foot higher than last year.

Yes, the upstream height indicators are very close to the weirs themselves (in many cases), making them a poor indicator of overall conditions. In Oxford the upstream meters at Osney and Iffley are running higher than last year but have not exceeded their all-time highs (since records began in '95). The downstream meters, however, have shown all-time highs, and Anu Dudhia's rather less technical data (a measurement of the river height at Folly Bridge) is at an all-time high of 43" (above 'normal' river levels).

Oxford has the usual problems - the large amount of housing built down Abingdon Road (New Hinksey) is flooded, and Abingdon Road itself is closed. Osney Island (much older terraced houses) has been defended by the EA's demountable flood defenses, which seem staggeringly effective for what they are.

[Chris A]

>
>
> Oxford has the usual problems - the large amount of housing built down Abingdon Road (New Hinksey) is flooded, and Abingdon Road itself is closed. Osney Island (much older terraced houses) has been defended by the EA's demountable flood defenses, which seem staggeringly effective for what they are.

The temporary barriers along the Severn are doing a sterling job as well otherwise large parts of Bewdley and Upton would be inundated. Almost up to the December 2012 levels in Worcester now.

[thomas....@googlemail.com]

Seen this photo go viral, I "think" it's photoshopped since I've seen an example of the same photo without the car and also although the river is high it's not quite high enough to carry cars off yet unless you drive into the river .

Still it was 8cm or so deep yesterday in the sculling bay, last year it didn't make it into the bay at all! Big floods

[Carl]

On 07/01/2014 19:58, Kit Davies wrote:

Some interesting background from:

http://www.jubileeriver.co.uk/Jubilee%20River%20story%20-%200801.htm#Hansard_%28Elliot_Morley%29

"Elliot Morley and the Jubilee River blame game
"In January 2003 hundreds of households downstream of Windsor suffered
serious flooding for the first time since 1947.
"As Minister responsible for flooding, Elliot Morley stated that the
newly built Jubilee River was not to blame for the flooding. He
rejected calls for a public inquiry and called for a stop on the blame
game. See what Elliot Morley said in March 2003 at the bottom of this
page....................
"It took many years for the facts to emerge...................
- the EA built a �110m world class, award winning flood alleviation
scheme MWEFAS/Jubilee River (the biggest in England?)
- given Ministerial approval after a Public Inquiry in 1992 - 'it
would be very embarrassing'"

And here's one reasom why, in this extract from 1992 Maidenhead, Windsor
and Eton Flood Alleviation Scheme Public Inquiry - Report to Minister.
"15. Further aspects of hydraulic performance
"15.1. It would be very embarrassing to all concerned if the intended
discharge capacity of the FRC (1) was not achieved. Thus the hydraulic
computations are particularly important, and in this context the
sensitivity of the channel to the roughness coefficients used and the
method of dealing with two-stage channels implicit in the modelling are
dominant issues.
"This is the largest fluvial flood alleviation scheme ever to be carried
out in the Thames region, and any deficiency in capacity would bring
wide-spread � and justified � criticism. It would be the largest
man-made river to be created in the UK with full regard to the latest
policies regarding environmental enhancements.
"The question of the flow capacity likely to be obtained is not an issue
that can be clouded over in the hope that design tolerances could later
explain away any deficiency. It is my firm view that there is no room
for retaining optimistic assumptions in the hydraulic design: in view
of the novelty and scale of environmental enhancements proposed, some
conservatism, some consideration of tolerances on assumptions is necessary."

The Jubilee River background info goes on:
" - then came the cost-cutting - MWEFAS cost reduction 1995 - 2002
- Thames dredging ceased without consultation - the dredging problem
- unable to carry its design capacity - Repaired Jubilee River
still 10% under capacity
- fell apart on first use - �5m in repair costs - The Myrke
embankment structural problems - �1.3m repair
- Myrke bend radius problem - the Myrke bend radius problem
- �2.75m out-of-court settlement for sub-standard design and
construction - �2.75m out-of-court settlement
- continually polluted with algae - the algae problem
- and still degrading today."

A longer list of issues up only to 2010 can be seen here:
http://www.jubileeriver.co.uk/whats%20wrong.htm

I refer to the above only as one of many sources of easily searched
relevant info & there is very much more.

The Jubilee river has been an inept, costly flood-_generation_ project.
Yet the pretence that its malfunctioning existence was generally
beneficial - shown year after year to be a lie - plus the deviousness of
crooked politicians (e.g. Morley) made it the excuse for even more
flood-plain construction meanwhile.

It's just one example of what happens when knaves & fools fuelled only
on policy-based evidence & their own egos get to run the show. Not
unlike the banks, which wrecked the economy, fiddle their taxes &
lending rates, felt no pain, were bailed out at our collective expense &
whose inept, bent leaders are still in clover.

Expect this chaos to repeat itself until a competent, fully-funded
rivers & land drainage management & staff is, if ever, put in place.
But it requires a clear brief, guaranteed funding & 20 years free from
all ministerial interference. Fat chance, I fear, that we will find
another Bazalgette this time around.

[Sarah Harbour]

He's the prat who was MP for Sunny Scunny while making fraudulent expenses claims, isn't he?

Sarah

[stew...@gmail.com]

Floods in Oxford are now receding from what's thought to be the highest in 'institutional memory' (none of the boatmen can remember it being higher). Water was 4" deep in Christ Church Boathouse, Longbridges perhaps a foot (there may still be some depth of water in there, I haven't been across). Downstream gauges at Iffley and Osney recorded new 'highest ever' marks (since 1995).

Christ Church Meadow is still a rowable lake, but the Cherwell is returning to something like a normal height.

Meanwhile at Wallingford, the river had risen over two metres, but is now receding. Water was thigh-deep in the OUBC car park. By great foresight of the designers, the 'inhabited' areas of Fleming Boathouse are up on stilts, about 4m above the normal river level. All the rafts - including in the wet launch shed - are on risers that allow over 3m of river height increase. Hence, only the boat bays and the blue shed have flooded.

[Carl]

Yes, these floods are now subsiding after over a week of increasing mayhem.

Here at 19:00 today in Chertsey the river is down 11cm from its peak of
2 days ago, putting it back to where it was all of a year & 2 weeks ago.
That 1-year old record was, according to the EA website, the highest
on record since this recording station was set up in 1985.

Which begs the question of what has happened to the records of January
2003 which, to every local's knowledge (including mine), was somewhat
higher than today's figure. Curious?

We now have all the water out of the workshop, leaving us with an
orange-scented wet floor to dry out after we had detergent swept it to
eliminate an all-pervading oil film which came from we don't know where.

That's another of the problems of uncontrolled flooding - pollution.
Now a mix of effluent, detergent & detritus is flowing down the river.
Hardly an environmental triumph for an outfit which had been selling the
lie that parsimony & neglect would improve the environment, & that
cutting back its expenditure on flood prevention will do no damage.

[Henry Law]

On 13/01/14 18:11, stew...@gmail.com wrote:
> By great foresight of the designers, the 'inhabited' areas of Fleming Boathouse are up on stilts, about 4m above the normal river level.

They could build houses like that too, if they wanted to. Building
normal buildings on flood plains is madness; building flood-plain
buildings is a different matter. They were doing it in the Bronze age,
and they do it even now in parts of the far East.

PS Not looked at Fleming Boathouse before; what a lovely place. For
others who've not seen it, look here (and watch for folding of this
rather long URL)

http://www.haraldjoergens.com/2013-03-13-ouwbc-training-wallingford/photos/1303131555125D27215HaraldJoergens_v1.jpg

--

Henry Law Manchester, England

[Richard du P]

This article

http://www.theguardian.com/commentisfree/2014/jan/13/flooding-public-spending-britain-europe-policies-homes

might provoke discussion? I think there's a whiff of a suggestion of governments using policy-based evidence.

Richard du P

[craigr...@googlemail.com]

Some further aerial shots, including Penton Hook & Laleham, Weybridge and Walton.

http://www.getsurrey.co.uk/news/local-news/sky-high-snaps-show-scale-thames-6503197

Craig.

[Carl]

Here (slightly edited) is part of my reply to just one of the very many
good friends who have sent us their good wishes since we were inundated
last week. He wondered if I'd seen the Guardian article:

"I hadn't seen Monbiot's article but I thought it excellent. I can't
entirely agree with his opposition to dredging. Once you have
"re-modelled" the flood plains as extensively as has been done in the
Thames valley - so they can no longer flood as they always used to do -
then you just have to get the waters away and swallow that
environmentally bitter pill.

"These repeated floods are social, economic & environmental disasters
which cannot be allowed to continue. Short of damming in the Maidenhead
flood plain to inundate its occupants, which would be rather
uncivilised, we have to ensure that the downstream channel - the Thames
- has sufficient capacity to take the much faster run-off without
drowning all the communities which, before the creation of the Jubilee
River, had been safe from all but the catastrophic floods of 1947.

"I fear we have no alternative (and I have some understanding of factors
affecting channel flow capacity), because we are so happy to flatten
meadows and forests for roads, and to excavate gravel for constructions
which will cover other meadows and forests, to opening up our river to
accept these larger flows by deepening and smoothing its bed. Or do we
think it wise to continue to flood everything from Windsor down to the
Tideway whenever we get what may become ever-increasing winter rains?

"This is serious stuff which has to be confronted. And that won't
happen with the present calibre of minister, prime minister and
Environment Agency management. Now where's my broom?!"

I'm happy to be able to say that we now have areas of dry floor, thanks
to the "7 maids with 7 mops", AKA me & my colleagues - re-fuelled by
Jan's mildly alcoholic bread pud. The remaining puddles are being
aqua-vacced away as I write this, & the skip-hire guy has just brought
us one of his finest 12 cu yd jobbies. Now to list all the damage &
loss for the insurers & start replacing fundamentals - like a pre-preg
freezer (& some pre-preg stock), damaged machinery, & get testing the
rest for signs of damage. Tomorrow we start straightening things out
for an early production re-start.

Thanks again to everyone who has sent us their best wishes, giving us
such a fantastic uplift. And to those who've even offered to come down
& get stuck in with us! And to Daniel, who's doing an internship with
us as part of his naval architecture course at Southampton Solent uni, &
despite my warning still came in here on Thursday when we were already
wading ankle deep in the rising floods.

Anyone wanting to see how it looked when the floods were near their
worst can take a peek on our FB page. We hope soon to post a few more
shots of today's status, but business goes before pleasure.

Cheers -

[Carl]

Unfortunately their gallery seems not to work
C

[Brian Chapman]

On Tuesday, 7 January 2014 19:58:20 UTC, Kit Davies wrote:

We stopped in Chateau Thierry a few years ago and were impressed by their flood resistant boathouse. Link below. Boats come out on trolleys down the ramp in the Summer. No idea what they do in the Winter, possibly too fast to row.

http://aviron.chateau02.free.fr/

[Brian Chapman]

Yes, I know gallery is broken but boathouse is pictured at top left.

better shot showing ramp.

http://www.archicontemporaine.org/RMA/p-8-lg0-Centre-nautique.htm?fiche_id=1770

[Carl]

As it says: "dans un Plan de Pr�vention du Risque d�Inondation". In
other words, it's on a recognised flood plain, where buildings must not
add to the flood risk by reducing the absorbent area of that plain.

After the University College Oxford boathouse was burned down in '99 I
suggested they diminish the flood hazards & enhance the flood plain by
rebuilding it as an on-land floatable structure, tethered to piles.
That would've been a real environmental gain, & you'd have thought a
go-ahead university might put its intellectual weight behind such a scheme.

That, as we know, would be far too daring, especially for anything
involving your average local planning department, since it reduces their
scope for monkeying with specifications to make life more difficult &
more costly, & the end result less useful in every sense. But such
narrow-mindedness does keep jobsworths in jobs - & worsens future flooding.

The lane leading to our works has seen terrible flooding of homes built
long ago (when these floods didn't happen). Newer houses built in place
of some of them had their roof heights restricted for "amenity reasons"
by the planning office so that they could have only 1 floor (never
recommended on a floodable river), even though built on modest stilts.
This despite there being 2-storey houses on the directly opposite bank
(not on stilts) & 2 colossal 3-story edifices quite recently erected on
the same stretch of river-front a few hundred metres downstream. Now
how did that happen?

Carl

[stew...@gmail.com]

Carl

Univ Boathouse may be a bit crap architecturally (it looks like a horrible black metal box), and useless as a club house - because the College were more interested in using the upstairs as a conference facility than as a space for the use of the club - but to the designers' credit it is built considerably higher up than all the other boathouses around the Isis. They were never at risk of their boat bays flooding. Every other college boathouse except Brasenose/Exeter had at least some water ingress - and we were very close.

Strangely, Longbridges Boathouse - built in 1997 - is the lowest down. I wonder if they struggled with planners when designing the new building.

Stewie

[Carl]

On 15/01/2014 16:48, stew...@gmail.com wrote:
> On Wednesday, 15 January 2014 13:04:32 UTC, Carl wrote:
>> On 15/01/2014 12:16, Brian Chapman wrote:
>>
>>> On Tuesday, 14 January 2014 12:32:29 UTC, Brian Chapman wrote:
>>
>>>> On Tuesday, 7 January 2014 19:58:20 UTC, Kit Davies wrote:
>>
>>>>
>>
>>>>> For those who may need it, here is a link to the Environment Agency's
>>

>>
>>>>> very useful live map showing flood warnings and alerts currently in place:
>>
>>

>>
>>>>> http://www.environment-agency.gov.uk/homeandleisure/floods/142151.aspx
>>

>>
>>>>> Unfortunately I can't link to specific geographic locations on the map,
>>

>>
>>>>> but zooming in on the Thames, the effect of the Millenium river is
>>

>>
>>>>> stark: a completely alert-free zone in an otherwise unbroken line of red.
>>

>>
>>>>> Kit
>>

>>
>>>> We stopped in Chateau Thierry a few years ago and were impressed by their flood resistant boathouse. Link below. Boats come out on trolleys down the ramp in the Summer. No idea what they do in the Winter, possibly too fast to row.
>>

>>
>>>> http://aviron.chateau02.free.fr/
>>
>>>
>>
>>> Yes, I know gallery is broken but boathouse is pictured at top left.
>>
>>>
>>
>>> better shot showing ramp.
>>
>>>
>>
>>> http://www.archicontemporaine.org/RMA/p-8-lg0-Centre-nautique.htm?fiche_id=1770
>>
>>
>>

>> As it says: "dans un Plan de Pr�vention du Risque d�Inondation". In

>>
>> other words, it's on a recognised flood plain, where buildings must not
>>
>> add to the flood risk by reducing the absorbent area of that plain.
>>
>>
>>
>> After the University College Oxford boathouse was burned down in '99 I
>>
>> suggested they diminish the flood hazards & enhance the flood plain by
>>
>> rebuilding it as an on-land floatable structure, tethered to piles.
>>
>> That would've been a real environmental gain, & you'd have thought a
>>
>> go-ahead university might put its intellectual weight behind such a scheme.
>>
>>
>>
>> That, as we know, would be far too daring, especially for anything
>>
>> involving your average local planning department, since it reduces their
>>
>> scope for monkeying with specifications to make life more difficult &
>>
>> more costly, & the end result less useful in every sense. But such
>>
>> narrow-mindedness does keep jobsworths in jobs - & worsens future flooding.
>>
>>
>>
>> The lane leading to our works has seen terrible flooding of homes built
>>
>> long ago (when these floods didn't happen). Newer houses built in place
>>
>> of some of them had their roof heights restricted for "amenity reasons"
>>
>> by the planning office so that they could have only 1 floor (never
>>
>> recommended on a floodable river), even though built on modest stilts.
>>
>> This despite there being 2-storey houses on the directly opposite bank
>>
>> (not on stilts) & 2 colossal 3-story edifices quite recently erected on
>>
>> the same stretch of river-front a few hundred metres downstream. Now
>>
>> how did that happen?
>>
>>
>>
>> Carl

>

> Carl
>
> Univ Boathouse may be a bit crap architecturally (it looks like a horrible black metal box), and useless as a club house - because the College were more interested in using the upstairs as a conference facility than as a space for the use of the club - but to the designers' credit it is built considerably higher up than all the other boathouses around the Isis. They were never at risk of their boat bays flooding. Every other college boathouse except Brasenose/Exeter had at least some water ingress - and we were very close.
>
> Strangely, Longbridges Boathouse - built in 1997 - is the lowest down. I wonder if they struggled with planners when designing the new building.
>
> Stewie
>

If the new boathouse's ground-floor elevation comes from a massive slab
of concrete, as at first it appears, that would be a monstrously
negative contribution to preserving the flood plain. But Oxford's city
planning department does seem to have rather a reputation for anality.

[andymck...@gmail.com]

On Wednesday, January 15, 2014 5:36:46 PM UTC, Carl wrote:
> On 15/01/2014 16:48, stew...@gmail.com wrote:
>
> > On Wednesday, 15 January 2014 13:04:32 UTC, Carl wrote:
>
> >> On 15/01/2014 12:16, Brian Chapman wrote:
>
> >>
>
> >>> On Tuesday, 14 January 2014 12:32:29 UTC, Brian Chapman wrote:
>
> >>
>
> >>>> On Tuesday, 7 January 2014 19:58:20 UTC, Kit Davies wrote:
>
> >>
>
> >>>>
>
> >>
>
> >>>>> For those who may need it, here is a link to the Environment Agency's
>
> >>
>
>
>
> >>
>
> >>>>> very useful live map showing flood warnings and alerts currently in place:
>
> >>
>
> >>
>
>
>
> >>
>
> >>>>> http://www.environment-agency.gov.uk/homeandleisure/floods/142151.aspx
>
> >>
>
>
>
> >>
>
> >>>>> Unfortunately I can't link to specific geographic locations on the map,
>
> >>
>
>
>
> >>
>
> >>>>> but zooming in on the Thames, the effect of the Millenium river is
>
> >>
>
>
>
> >>
>
> >>>>> stark: a completely alert-free zone in an otherwise unbroken line of red.
>
> >>
>
>
>
> >>
>
> >>>>> Kit
>
> >>
>
>
>
> >>
>
> >>>> We stopped in Chateau Thierry a few years ago and were impressed by their flood resistant boathouse. Link below. Boats come out on trolleys down the ramp in the Summer. No idea what they do in the Winter, possibly too fast to row.
>
> >>
>
>
>
> >>
>
> >>>> http://aviron.chateau02.free.fr/
>
> >>
>
> >>>
>
> >>
>
> >>> Yes, I know gallery is broken but boathouse is pictured at top left.
>
> >>
>
> >>>
>
> >>
>
> >>> better shot showing ramp.
>
> >>
>
> >>>
>
> >>
>
> >>> http://www.archicontemporaine.org/RMA/p-8-lg0-Centre-nautique.htm?fiche_id=1770
>
> >>
>
> >>
>
> >>
>

> >> As it says: "dans un Plan de Pr�vention du Risque d�Inondation". In

If you want to see a good example of how to build a boathouse on a flooding river - check out this from Linz on the Danube, at their International regatta course - convert a great big ship into a boathouse, and you are all sorted!

http://www.wru23ch2013.com/fileadmin/wru23ch2013/pressefotos/Hochwasser/Hochwasser_Luftaufnahme2_wolfstudios.at.JPG

They get serious flooding - there's at least a 10 row grandstand somewhere under that water.

Back to the Thames, we have just gone through the design hoops for our new boathouse for Goring gap Boat Club. We are going to have porous floors and porous walls and balance any areas where we build up from the plain with compensating excavation. It means that the boathouse will flood in a 1:10 year event - but we are expecting it to, so we will just set things out internally to cope. Whatever one may think about how floods and floodplains should be managed, the reality is that we live in an austere, highly populated and quite wet country, and things aren't going to change quickly - floods on rivers worth rowing on are always going to happen.

Andy

[craigr...@googlemail.com]

Spotted this on the TV news this morning -

http://www.bbc.co.uk/news/uk-politics-25752320

Craig.

[Henry Law]

On 16/01/14 10:01, andymck...@gmail.com wrote:
> but we are expecting it to

It's the only sane approach.

Interested to hear about the project; I hold GGBC high in my affections,
for reasons detailed in the group in 2009 here
https://groups.google.com/forum/?hl=en#!topicsearchin/rec.sport.rowing/ggbc$20group$3Arec.sport.rowing|sort:date|spell:true/rec.sport.rowing/0glfuk9sylo

What an absurd URL!

[Sarah Harbour]

Yes, and that moron Charlie Stayt then asked the woman a stupid question about 'where is the extra water going to go', which she'd just explained really well... Seriously, I don't know how anyone expects the wider public to understand anything when you've got TV presenters and journalists saying/writing garbage the entire time (that rolled off the back of me reading reports in the Mirror and Telegraph(!) saying that the Aurora Borealis was 'burning gases' last week - what the heck?!)

Sarah

[stew...@gmail.com]

Carl

Sorry to bring back this thread months down the line, but a few weeks ago I happened to remember this thread and decide to take a proper look at Univ Boathouse. Or more accurately, underneath it.

Although the floor is a concrete slab (reputed to contain underfloor heating to dry the boats out!), it's a concrete slab on 2ft tall stilts, leaving a large void under the building which is open-sided. So the boathouse floor is well above any potential flooding, but significant storage volume has not been removed from the flood plain.

Stewie

[Carl]

Many thanks for the update. No Thames Valley boathouse has the
slightest need of underfloor heating, even supposing it uses a ground-
or water-source heat pump for the purpose (which I somehow doubt, but I
could be pleasantly surprised). However, I get a steady trickle of
enquiries from architects & student architects around the world
requesting "plans for your boats so we can design a boathouse". The
best advice I can give them is to get off their designer chairs and
spend a week or three mingling with rowers (better still, join a club &
row) so that they get a sense of how a rowing club really functions - &
then design for those needs rather than invent some fancy boat palace.

I do applaud the raising of the floor as I think all flood-plain
buildings ought to be made like that, to allow storage volume (not such
a problem), good drainage & unobstructed through-flow (that is
important. In general the original soil & substrata ought not to be
screeded over or built into, & roads, drives & access-ways should all be
porous. I'm sure there are better-specified scenarios than the above,
but it'd be good to see a little more common sense & a lot less of the
current fashion for carpeting built-up land in tarmac, pavings &
concrete. Thought is also needed into buried structures such as drains
& other services, as well as roadways, which act as impermeable dams to
the natural flows of groundwater through the substrata. In short, a
properly hydrological approach, with drainage to the fore & the beds &
banks of our main drains - the rivers - kept smooth, of adequate depth &
width & free from overgrowth. Sadly, such approaches are conspicuous by
their absence in the UK.

Cheers -

[Kit Davies]

By coincidence, this topic came up on last night's Grand Designs on
Channel 4. The subject was a house built on Lock Island at Marlow. It
comprised of a lightweight wooden structure upper 2 floors built on a
waterproof concrete basement, with the whole lot floating in a wet dock
between 4 'dolphins' (large upright girders), such that the house can
rise up to 12' with any flooding.

It looked beautiful too.

Kit

[Kit Davies]

Feel a bit dirty a) replying to myself and b) linking to the Daily Mail,
but here goes:
http://www.dailymail.co.uk/news/article-2100757/Introducing-Britains-amphibious-house-rises-water-escape-flood.html

[andymck...@gmail.com]

I think underfloor heating would be brilliant - imagine the pleasure of warm toasty feet when you are putting the boat away!

Sadly our new boathouse, on which construction will start in the spring will have a permeable floor that will sit about 0.3 metres below the 2014 flood level, and porous external walls that water can flow through. We always wanted to make sure that we didn't do anything that might be seen to exacerbate flooding, and even if we hadn't planned it that way, the EA would have made us do it! It means that our design puts all services and storage significantly higher - the only thing affected by floods will be boats on our bottom racks, which will have to get moved to trestles ahead of a flood - at least on the Thames we get reasonable advance notice of a flood!

I did give serious thought to moving our current temporary site's portaloo to atop a spare pontoon last winter - and if floods threaten this winter that's what I will do! Not sure grand designs will come and film it though.

Andy

[Carl]

> I think underfloor heating would be brilliant - imagine the pleasure of warm toasty feet when you are putting the boat away!
>
> Sadly our new boathouse, on which construction will start in the spring will have a permeable floor that will sit about 0.3 metres below the 2014 flood level, and porous external walls that water can flow through. We always wanted to make sure that we didn't do anything that might be seen to exacerbate flooding, and even if we hadn't planned it that way, the EA would have made us do it! It means that our design puts all services and storage significantly higher - the only thing affected by floods will be boats on our bottom racks, which will have to get moved to trestles ahead of a flood - at least on the Thames we get reasonable advance notice of a flood!
>
> I did give serious thought to moving our current temporary site's portaloo to atop a spare pontoon last winter - and if floods threaten this winter that's what I will do! Not sure grand designs will come and film it though.
>
> Andy
>

I guess an elevated floor would have been a chunk more costly? And
doubtless your building would then have exceeded some notional height
limit, from which developers of doomed-to-stay empty office towers in
London are always exempt?

Restrictions on dredging, the only effective way of preventing flooding
of some major UK rivers, are imposed under the articles of faith which
define dredgings are pollutants. But when your boathouse does flood its
surfaces & surroundings will be left covered in mud & fine silt. These
ultra-fine-grained materials will be the most polluted products of river
bed erosion by those extreme flows. Indeed, funnily enough, the UK's
Environment Agency still clings to its mantra that our rivers are
"self-dredging", which is only true in that, not being maintained they
scour, erode, re-arrange & deposit their beds & banks in a manner which
_reduces_ their bank-full flow capacity.

After this winter's floods, everything here was covered by layers of
silt of minute particle size. Then came dry weather, wind & traffic,
stirring & blowing it about, coating everything from the insides of
computers & cars intake filters to the throats, sinuses & gas-exchange
surfaces of every living creature.

Rather than prevent floods by well-managed dredging, our rivers are
deliberately neglected so that life is disrupted by floods & lives are
shortened by inhalation of substances deemed so toxic that we must not
dredge them from the river bed.

You couldn't make it up! I'm in favour of acting in the greenest, most
environmentally sound ways but, unless shortening of lives fits that
agenda, it is plain that regular dredging under controlled conditions,
with routine analysis of its products and recovery of any pollutants, is
the only sane way to proceed on every possible count.

[Henry Law]

On 16/10/14 19:22, Carl wrote:
> our rivers are "self-dredging"

Doesn't that violate the 2nd law of thermodynamics?

[Carl]

On 16/10/2014 21:25, Henry Law wrote:
> On 16/10/14 19:22, Carl wrote:
>> our rivers are "self-dredging"
>
> Doesn't that violate the 2nd law of thermodynamics?
>

Yes. In natural systems order decreases & entropy increases.
Everything gets messier & more chaotic. And if we don't intervene a
once fine, man-managed river will eventually revert to its former
non-navigable mess of swamps, streams & islands. The locals will revert
to wearing skins & woad & plod around saying "Ugh" to each other. Great
openings, however, for raft & coracle makers.

We saw this process beginning in the neglect & decline of the Schinias
Olympic course in Greece (& many others of their Olympic venues).

To reduce the entropy & disorder of our rivers would, of course, mean an
increase entropy elsewhere - from using energy in various ways in the
dredging process. But we survive to make things better - & if we
generate that energy from low or zero carbon processes we'll be running
on sunshine, which seems likely to be around for quite a while.

Blessed are the thermodynamicists.....

Cheers -

[andymck...@gmail.com]

Yes, elevating the floor imposes its own set of problems, slopes to the river and overall building height. We are lucky to have the opportunity to build in an area of Outstanding Natural Beauty, so keeping a low profile is one factor. I'm well familiar with Thames silt - the shed on our current site has flooded to 60 centimetres deep two years in a row, and muggins here was the one carrying buckets of water and sluicing out the silt.

Fortunately being rural I can tell myself that it is mainly rich organic topsoil, and therefore probably a good thing!

I know the arguments about dredging are both complicated and emotive, but the Thames does self scour in a lot of places - after all the current river channel is a lot narrower and a lot deeper than it would have been a few hundred years ago, and much less encumbered by weirs and fish traps and jetties etc. I occasionally punt on the middle Thames, and the extent of bed movement after a high flood is quite dramatic. Of course my middle Thames scour is quite probably Carl's lower Thames dump of silt!

Even with 2014 the overall trend in Thames flooding is for lower peaks, and less disruption, than there was in earlier centuries. As humans (and certainly as rowers) we like living by rivers - for their fertile floodplains (all that silt...) - their transport capacity - for fresh water, for flat ground to build on - we just should never forget that they are bigger and stronger than we are, and have been around a lot longer, and occasionally they bite!

Andy

[Carl]

So it's you, Andy, who washes down all that silt for us to inhale? What
a cad, Sir!

The concerns voiced, but largely without supporting evidence, are that
river silt is rich in heavy metals which, as we know, are not best
consumed. The (officially) unvoiced concerns are that, as a by-product
of activities at AWRE Aldermaston & their less than careful effluent
disposal practices of earlier years, river silt downstream is high in
particularly unpleasant kinds of heavy metals. Similarly cavalier
discharge policies ("It's OK, the amount of radioactivity will be just a
drop in the ocean", I was told as a student) at what were formerly known
as Windscale & Calder Hall in Cumbria have resulted in unduly hight
levels of radioactivity in certain parts of the Irish Sea.

So behind the cock-eyed non-dredge policy may lurk the vain hope of
letting sleeping nuclides lie. But, when the river floods, that policy
goes to pot.

As regards historic and recent Thames flooding:
http://www.ceh.ac.uk/data/nrfa/nhmp/annual_review/feature_articles/Flow_Gauging_on_River_Thames_100_Years.pdf
shows an interesting variation in rainfall over a 100-year period since
flow gauging began on the Thames, while data to the present shows an
increasing frequency of high flows & levels in the last decade or so.

What we know is that we get "weather", that our rainfall is determined
by global events & that recent years have seen an increased intensity of
rainfall which is predicted to continue & bring increased flooding as
atmospheric water burden (& sea levels) continue to rise.

No, rivers do _not_ self-dredge. Yes they do scour, but hand in hand
with scour goes sedimentation. Single deep & broad channels maximise
flow capacity for any given cross-section but normal erosion processes
lead to multiple, uneven channels with far greater tendency to overflow
their banks. Thus your new boathouse has a good chance in that scenario
of being swallowed up by natural erosion.

The Thames has gravely reduced in bank-full capacity in recent years,
this falling by 30% since the end of routine dredging after a century of
maintenance & works which had progressively enhanced that capacity.
Where bushes & trees were kept from the banks as a matter of
navigational & drainage common sense these banks are now heavily
overgrown while the river beds have become irregular & deeply
corrugated, imposing further erosion risks & greatly increased pressure
drops (which translate into river gradients) for the same flows of
earlier years.

Yes, rivers have been around far longer than us & we must respect them.
But we also need to live harmoniously with then, & keep them from our
doors - it can be done. While mad things have been done in recent years
under the opposing influences of commercial pressures & the controlling
naivete of those who profess to love nature, we do have the science &
capacity to achieve that necessary harmony without wrecking anything.
What in the UK we lack is the collective wit & will to see the problem
and engineer its optimum solution. Centuries of history show that,
until senior politicians themselves start suffering from the
consequences of their own inanity, that's how it will stay.

Cheers -

[andymck...@gmail.com]

Carl

You might be interested in a more recent publication than the one you referenced: 'The Thames flood series: a lack of trend in flood
magnitude and a decline in maximum levels', http://nora.nerc.ac.uk/18966/1/N018966PP.pdf

Andy

[Carl]

On 20/10/2014 10:13, andymck...@gmail.com wrote:
> Carl
>
> You might be interested in a more recent publication than the one you referenced: 'The Thames flood series: a lack of trend in flood
> magnitude and a decline in maximum levels',http://nora.nerc.ac.uk/18966/1/N018966PP.pdf
>
> Andy

A very interesting paper, trying hard to make sense of a very messy data
set. But too many years in engineering analysis make me wary of
correlations purporting to interpret what appear to be completely random
messes of points.

Perhaps the most interesting (were we to treat it as signifying a trend)
is the final figure: Fig. 8 "Decadal flow events exceeding 350 cumecs".
And that ends, presumably, at 2010 with the highest decadal total of
such events.

For the preceding Fig. 7 the data set ends at 1980, which was in the
depth of a long dry period (1976 saw a record drought in England).

Fig. 5 projects an annual frequency of >250 cumec flows which is on a
rising trend (supposedly).

Fig. 4 projects a flow increase, again with a huge scatter of points.

Fig. 3 shows a huge spread of data points, curve-fitted to give a
possible slightly downward trend in 3-day rainfall maxima, but its very
last data point is higher than any other over the preceding century.

And, in the text, what is written in lines 198-198 is completely washed
away by more recent events.

However, this all pales into insignificance when you factor in the
measurable decline of ~30% in the River Thames channel's bank-full flow
capacity over these last 20+ years. This means than an event which, 20
years ago, took us to the brink of flooding will today (& does) cause
the river to flood over its banks.

So neglect of river maintenance has left our river unable to handle
flows which once it would have taken in its stride.

[Carl]

On 20/10/2014 11:01, Carl wrote:
> And, in the text, what is written in lines 198-198 is completely washed
> away by more recent events.

A bit of a typo there, sorry. Should have read:
"And, in the text, what is written in lines 194-198 is completely washed

away by more recent events."

[andymck...@gmail.com]

The problem with hydrological sciences are that we more or less never have enough data, and you never get controlled replicate measurements. What we really need are another 20 or 30 really big floods on the Thames, and we might begin to understand how they work, and outr data points wouldn't be as messy. However with a rowing hat on a couple of years when I don't have to don waders to check that the club shed hasn't actually floated away would be quite welcome!

Andy

[Carl]

Andy -

I entirely favour doing lots of experiments with proper controls. I do,
however, have a problem with me, or anyone else, being the flood-test
dummy. I know, it's damnedly unsporting of me, but when you suggest
that, "we really need another 20 or 30 big floods", I completely
understand where you're coming from but find it rather hard to give your
proposal my unstinting support ;)

Also, where are you going to get your R. Thames catchment replica? That
guy in the Hitch-hikers' Guide who created the Fiords - is he free?

No one pretends, least of all me, that Hydrology is simple or precise on
a whole-catchment, real-time basis. What we do know, however, is what
not to do. Sadly, we have arrogant, technically-ignorant politicians
with nutty agendas who hold the purse-strings. Theirs is the power of
hire & fire. Sitting comfortably behind dry desks, they tell the
non-hydrologist (& former politician) heads of such as the EA, & they
tell Joe Public, what to say & believe while the hydrological staff must
say nowt on pain of losing their jobs, there having been a 500-head
redundancy tally lined up at the time of the recent floods. Those
floods saved a lot of jobs, but no lessons were learned & no meaningful
plans developed, so we stumble blindly on.

Cheers -

Carl

--
Carl Douglas Racing Shells -
Fine Small-Boats/AeRoWing Low-drag Riggers/Advanced Accessories
Write: Harris Boatyard, Laleham Reach, Chertsey KT16 8RP, UK
Find: tinyurl.com/2tqujf
Email: ca...@carldouglasrowing.com Tel: +44(0)1932-570946 Fax: -563682

URLs: carldouglasrowing.com & now on Facebook @ CarlDouglasRacingShells

[magnus....@gmail.com]

Just seen this

http://www.bbc.co.uk/news/uk-england-surrey-29732804

Apparently Runnymede Council has reclassified the sort of flooding we saw last winter as "1 in 20 years" rather than 1 in 100 as it had been before.

I wonder how they'll re-reclassify when it happens again this winter? I suspect it's categorized as 1 in 20 now rather than considered as likely as, say, snow, because that way they can justify doing nothing material now by way of prevention.

[Carl]

Yes, I saw that this morning! It's statistical nonsense. As vacuous as
the line on the borough plan which puts my house above the 1000-year
flood. The last 11 years have seen 3 mega-floods, plus a ramp of events
which flooded some & came too close to the rest for comfort. 2000 was
also "interesting".

The facts are that: weather patterns have changed & are still changing,
the flood plain is still being concreted over, the river was messed
around with to protect one locality to the detriment of others, it has
not been maintained for almost 20 years, its banks are overgrown & being
undercut by scour & its eroded bed is becoming ever more irregular. But
we're told there's no money for remedial measures.

A document just published by local councils quotes the EA calling the
Thames "self-cleaning" - an interesting shift from its former, equally
bogus "self-dredging" terminology. Doubtless EA PR-wonks (EA spends
more on PR than on flood prevention, has flogged off its dredgers &
retired their operators) are banishing all reference to dredging.
"Self-cleaning" sounds cuddly & hygienic but is meaningless. And still
rivers of raw sewage will run through people's houses.

Remember PM Cameron announcing, during the floods, that money would be
no object? A career limited to PR & politics is hardly conducive to
meaning what one says.

[Carl]

On 23/10/2014 15:44, Carl wrote:
> And still rivers of raw sewage will run through people's houses.

To underline the inept & gutless response to local flooding by the
supposedly relevant so-called authorities, for whose disservices we have
to pay:
http://www.bbc.co.uk/news/uk-england-surrey-29744279

I pass frequently along that road. Imagine how this affects (& could so
easily infect) the hapless victims of this collective neglect by fat &
wealthy men. Never in my worst dreams had I thought that Britain, where
we used to care for & about each other, could ever sink so low.

Apologies for this slight off-topic post, but in England we even expect
rowers to row through this stuff.

[Kit Davies]

On 16/10/2014 07:59, Kit Davies wrote:

Here's another UK-based architect offering a design for a flood-proof,
floating house:

http://www.gizmag.com/floating-house-carl-turner-architects/35641/

Kit

[Carl]

On 26/01/2015 16:52, Kit Davies wrote:
>> By coincidence, this topic came up on last night's Grand Designs on
>> Channel 4. The subject was a house built on Lock Island at Marlow. It
>> comprised of a lightweight wooden structure upper 2 floors built on a
>> waterproof concrete basement, with the whole lot floating in a wet dock
>> between 4 'dolphins' (large upright girders), such that the house can
>> rise up to 12' with any flooding.
>>
>> It looked beautiful too.
>>
>> Kit
>>
> Here's another UK-based architect offering a design for a flood-proof,
> floating house:
>
> http://www.gizmag.com/floating-house-carl-turner-architects/35641/
>
> Kit

Maybe a tad boxy, although the concept's old & well tried. A word of
caution: has roll-stability been fully considered in the event of gale
force side-winds?

That flat side, plus the strange square box device on the roof,
constitute one heck of a sail? With its relatively narrow beam & flat
bottom, it could develop an unstoppable roll on a windy day, exacerbated
by the sloshing of water in a full bath & cold-water tank upstairs.
And, if there was water in the bilges, free-surface-effect instability
becomes an added hazard (as seen in the infamous Herald of Free
Enterprise roll-over).

I'd advise a cooperation between architect & naval architect.

Cheers -

[Anatole Beams]

Don't forget to close the garage doors before an outing.