How much rain will cure hosepipe issues/canal depth/reservoir levels?

[Twister_Ken]

Here's a crazy thought, then...

...feel free to point out the flaws that I haven't thought of yet, it being less than a minute since it came to me...

If a very tidal river like the Arun, was dammed at its mouth, down in Littlehampton...surely the substantial lower course of the river, which currently floods with brine every high tide, could be permanently filled with fresh water, without inundating any new land?

Quite an engineering job, doubtless, but no more than has been achieved before, surely? The fact that the Arun's mouth is no more than 50m wide, might make it a good deal easier (faster, anyway) to build.

The flat land around Chichester/Bognor is largely agricultural...and must need a good deal of watering in drought periods. The river-water wouldn't need a lot of lifting, from the present high-water mark, to reach crop-spots.

Isn't current policy, to make excuses, while every hour, thousand of tonnes of usable fresh river water pours into the sea?

Umm...I just remembered this is a boating forum. Well, couldn't the dam incorporate a lock, for access? Like many marinas?

Careful Dan, you'll have the RSPB as implacable enemies (they know where you live). One of the most powerful lobby groups in the country, extremely well connected, very dangerous people!

Patron:
Her Majesty the Queen
President:
Ms Kate Humble
Vice Presidents:
Dr Elizabeth Andrews MBE, DL
Sir David Attenborough OM CH CVO CBE FRS
Mr Nick Baker
Mr Adrian Darby OBE
The Earl of Lindsay
Professor Ian Newton OBE FRS FRSE
Mr Chris Packham
Sir Graham Wynne CBE
Viscount Blakenham
Professor Sir John Lawton CBE FRS
Sir John Lister-Kaye Bt
Mr Bill Oddie OBE
Mr Julian Pettifer OBE
Baroness Young of Old Scone

 

[lw395]

Not much water flows down the Arun in drought periods.
Yes you could dam it, and draw off the water, but it's not a big area, being a narrow river with a short tidal section. I would also not be surprised if the water turned brackish due to salt water permeating the land at sea level?
You also have to deal with the considerable amount of silt that it carries.
Also the way the tidal section is used to drain the surrounding area.

I think some water is already drawn off the Arun a little higher up?
It is probably a case of cost/benefit. Land around that area is very expensive, so any impact on property costs a lot. Water is still cheap but we cannot predict how reliable the rain is in future years.
In greece, many houses have a 'cistern' holding perhaps a hundred cubic metres under the house. That is worth doing, because water costs a lot there if you are not on the mains, I think around 10 or 20 euro a cubic metre is what our friends pay. If our water gets ten times as expensive as it is now, it may be worthwhile to store our own rainwater here, but it does add a lot to the cost of a house.

 

[Wunja]

If a very tidal river like the Arun, was dammed at its mouth, down in Littlehampton...surely the substantial lower course of the river, which currently floods with brine every high tide, could be permanently filled with fresh water, without inundating any new land?

They have done this in Holland as part of flood defences.

It caused a lot of damage to the ecology of the region and now most of the sea dams are open to allow some exchange of fresh / sea water.

 

[Greenheart]

Tidal rivers expose the shallows twice a day. Permanent flooding is permanent.

That should be the absolute last resort to be considered only when everything else has been tried... including population relocation.

I agree it'd likely be a terrible loss to wildlife, but possibly a boon to human existence thereabouts. I think it might be optimistic to expect humans to up-sticks and head for where there's water, rather than quickly and relatively easily, storing river water.

I think it would also take a very long time before the water contained in such areas would be drinkable - it will be sitting on mud and sand that is well loaded with salt.

This would be an osmosis question, wouldn't it? I mean, if salt in the riverbed rapidly leaches into the dammed fresh water, it can be all let out at a low water spring, then allowed to refill...a few flushes like that (or a few dozen?) and there'll be less salt each time, no?

If on the other hand, the salt only slowly pollutes the accumulated river water, a good deal might be extracted (particularly upstream) before the majority needs to be let go, seawards.

Either way, longterm, it must offer the enormous resource of the river basin's outpourings, lots of which are currently lost.

 

[WilliamUK]

I agree it'd likely be a terrible loss to wildlife, but possibly a boon to human existence thereabouts. I think it might be optimistic to expect humans to up-sticks and head for where there's water, rather than quickly and relatively easily, storing river water.

I'm not an "overpopulation", human-hating nut so please don't mistake what I'm going to say here.

Human existence thereabouts is the main part of the problem. It is our overuse of water, our insistence on using drinking water for almost everything, our lack of motivation to be conservative with or re-use water and our lack of will to actually fix the problems we cause that waste good water.

I'm not saying I expect people to up sticks. I'm saying we should not wipe out masses of habitat because we can't be bothered doing things the right way.

If we (rightly) eliminate the option of permanently flooding tidal estuaries and instead focus on ourselves we have basically three options.

1> Do it the hard, right way and change the way we use water while stemming the systemic waste.
2> Do nothing and put up with shortages.
3> Move.

Throughout human history people have moved for resources. I'm not really sure why we think we should be all that different now. Sure, technology has allowed us to largely ignore our natural way, and politics (all the way from serfdom to now) have prevented us from following it (now, as then, you effectively need permission to move)... but that is the entire cause of our current problem - and probably future ones.

We have come to choose where to live based entirely on where we grew up and/or where we want to live... with little or no attention paid to where we should live based on available resources.

Sure, building a dam across the mouth of an estuary and permanently flooding the area with fresh water would be easier and probably cheaper than fixing the problem, but do you seriously think that's looking forwards?
With wasteful water-use, leaky systems and the almost complete disregard for resources when considering where or how to live... we could dam every estuary in the dry parts of the British Isles, have 40 days and nights of biblical-grade rain to give them a head start and they'd still end up short of water.

All that lost habitat in exchange for being able to continue on our wasteful little way.

Seems like a poor trade to me.

 

[Greenheart]

I was thinking as you do, William, but speaking as devil's advocate...

Please, don’t make me look like the bad guy, here. I’m much inclined to encourage seawater loo-cisterns, sensible restraint in fresh-water usage, and fixing those insanely wasteful leaks. But…

…as a species, surely we are already vastly over-populous for the area we occupy, and unless, on improbably scrupulous moral bases, we resolve to emigrate, we must pillage whatever opportunities nature unwittingly supplies.

However ugly that sounds, it’s far more likely than ‘doing the right thing’, as I’d personally prefer...

...if we're in for a long period of droughts, as well as having ever-more population to wash and water, we'll need every answer.

PS, Ken, I've got nothing against birds! Some of my best friends...

 

[DJE]

I’m much inclined to encourage seawater loo-cisterns,

So you're going to lay sea water distirbution mains to every house in parallel with the existing potable water mains.
That would make a National water transfer system look cheap! Oh and the sea water would probably kill off the bugs in the biological sewage treatment plants.

One of many, many non-starters on this thread.

 

[Greenheart]

...the sea water would probably kill off the bugs in the biological sewage treatment plants.

That, I didn't know. Good point, if it's true. Pity you dressed it up as snarling criticism.

I expect you're right. Much better to do nothing. Why worry?

 

[WilliamUK]

Please, don’t make me look like the bad guy, here.

Certainly not trying to do that.
I'm addressing the ideas, not the person having them...
When I'm talking about suggestions and the things we do wrong, I'm talking about possible solutions to the problem we all have, not shooting messengers.

I’m much inclined to encourage seawater loo-cisterns, sensible restraint in fresh-water usage, and fixing those insanely wasteful leaks. But…

Seawater where appropriate, but probably not generally.
There's no need whatsoever to use seawater to flush toilets when every house with running water has a plentiful supply of grey water they could use for the job.

…as a species, surely we are already vastly over-populous for the area we occupy, and unless, on improbably scrupulous moral bases, we resolve to emigrate, we must pillage whatever opportunities nature unwittingly supplies.

However ugly that sounds, it’s far more likely than ‘doing the right thing’, as I’d personally prefer...

...if we're in for a long period of droughts, as well as having ever-more population to wash and water, we'll need every answer.

PS, Ken, I've got nothing against birds! Some of my best friends...

Perfectly clean rainwater falls on our roofs, into gutters and down into the sewers. Why does it not flow into our gutters, into a cistern below the house and only when that's watered the whole garden and is still overflowing on into the sewer?

Such a system (edit - I mean estuary damming here) would almost certainly be paid for through taxation. A costly and phenomenally wasteful means of funding. I wouldn't even want to hazard a guess at how much such a dam would cost (on just one river) but I suspect it might actually be CHEAPER (and if not, not much more expensive) to embark on a program of moving to parallel domestic systems (rainwater collection, grey-water reuse for gardens and flushing... possibly even micro-production of potable water on the domestic or local level in the very long term) and without any of the environmental disaster that damming invites.

I don't believe we DO need every answer to meet the water needs... I believe we need the right answers.

Continuing with the status quo as far as water systems and use are concerned precludes any possibility of having enough to go around long term.

Leaks must be stopped rapidly when found. Proactive methods to FIND leaks must be begun. Potable water should be used primarily for drinking. Rainwater should be collected domestically. Grey water should be used in all appropriate ways (toilets, gardens and so on).

Until we've done all of the above and started requiring all new housing estates to be built with parallel water systems (potable and non-potable), cisterns and so on... we shouldn't even be considering large scale habitat destruction to take up the slack.

 

[Greenheart]

Agreed. That's all very sound good sense. I just don't see it being the government position, any time soon.

I just heard the south is in for heavy rain. That should defer their need to worry, for a week or so...

 

[WilliamUK]

Actually, Dan (and anyone else)... I glossed over this a bit swiftly above.

If at any point I come across like I'm having a personal dig, please disregard it. As a rule I don't behave that way.

I'm always open to discussing ideas about topics that engage me, but (as you'll have noted) can be a bit full-on when I pick holes.

For me, conversations like this really are a matter of addressing the matter at hand and points raised about it - I'm entirely capable of separating my views of the subject from my views of others involved in the conversation.

If I've made you think I was attacking you or trying to make you look bad, I can only apologise for my choice of words and tone. If it happens again, please remember this post and realise I was probably just getting stuck into the topic and not you.

Hopefully that clears it up a bit better.

 

[WilliamUK]

Agreed. That's all very sound good sense. I just don't see it being the government position, any time soon.

I just heard the south is in for heavy rain. That should defer their need to worry, for a week or so...

Not until it becomes politically expedient to make it the position. Politicians these days are in it for the career. "What your country can do for you, not what you can do for your country." to butcher a well known one.

If they feel their job may be on the line, they'll take a stand whichever way they need to. A former MP that I know personally once asked a question on a VERY hot potato subject years ago - pushing the way public opinion seemed to be going. He was right.
Trouble is - he didn't actually agree, as far as I can tell.

It's all about job security for them.

 

[Greenheart]

If at any point I come across like I'm having a personal dig, please disregard it. As a rule I don't behave that way.

No problem, William. I wasn't feeling under unfair attack - I just didn't want to appear to believe that responsible solutions to water shortages, are too much bother. I'd been trying to see the question from the probable, lamentably myopic, traditional human p.o.v!

Re politicians...are there ever any instances of them following the wider public interest, if it doesn't shine back on them?!

Grey water re-use certainly sounds practical and possible. Even a water-butt in the cellar, with an overflow to a drain, and a pump to the loo cisterns upstairs, wouldn't be hard to rig up. There ought to be subsidies, the same way solar users are (or were) awarded.

I wonder what proportion of their potable water, most homes currently put into loo cisterns?

 

[WilliamUK]

No problem, William. I wasn't feeling under unfair attack - I just didn't want to appear to believe that responsible solutions to water shortages, are too much bother. I'd been trying to see the question from the probable, lamentably myopic, traditional human p.o.v!

Re politicians...are there ever any instances of them following the wider public interest, if it doesn't shine back on them?!

We have an accord.
Not too much bother and probably the last choice.

Grey water re-use certainly sounds practical and possible. Even a water-butt in the cellar, with an overflow to a drain, and a pump to the loo cisterns upstairs, wouldn't be hard to rig up. There ought to be subsidies, the same way solar users are (or were) awarded.

Not difficult at all, I don't think.
I'm not sure about subsidies though... falsely skews market prices (generally buoying prices when competition should bring them down) and again costs more than it would have either way.

Subsidies come from taxation, so every £1 spent on subsidising installs probably cost the homeowner being subsidised £1.20 or more to pay for it... and that's not forgetting the subsidies won't be paid for from taxes but from loans that carry interest and make it an even more expensive price.

It's probably becoming clear now that I'm no supporter of government in most areas and that I believe lower taxation across the board leaving people with more of the money they earned and so more disposable income would mean far more people could afford such systems without needing to rely on "the government" to pay for it.

That's a rant best saved for another thread (and one which I probably won't get involved in) though.

I wonder what proportion of their potable water, most homes currently put into loo cisterns?

Family of 4.
Much touted 2.5litres each per day (drunk as squash, tea, water and what have you... worst case scenario is no fluids from fruit juices and the like so let's assume that.)
Total drunk = 10 litres per day.

Washing the pots after each meal (3 per day for a home-working, home-schooling family - again heaviest imagined water use) will use about 15 litres per time, so 45 litres per day.

Toilet cisterns vary but let's assume a standard slimline one without any modifications to reduce use and a double flush-button.
Not wanting to be too biological about it, let's say two large and 4 small flushes per person.
13 litres per person per day.
52 litres for the family.


So... use for drinking and washing the pots: 55 litres.
Literally flushed down the toilet: 52 litres.

Non-potable could be used for washing the pots and grey could be used for the toilet, so split that way it's:

Potable water drunk: 10 litres.
Potable water wasted: 97 litres.

Nice.

Obviously I've not counted potable water poured onto the garden (wasted), used to wash the car (wasted) or used to cook with (not wasted) which would change things a bit - but I'm not about to sit here and do all that "average use" research.

 

[WilliamUK]

So... use for drinking and washing the pots: 55 litres.
Literally flushed down the toilet: 52 litres.

Non-potable could be used for washing the pots and grey could be used for the toilet, so split that way it's:

Potable water drunk: 10 litres.
Potable water wasted: 97 litres.

Nice.

I hate perspective.
I knew we were wasteful here (me included if I'm being brutally honest) and yet I'm stunned by that... and I've assumed a probably heavier than reasonable use of potable water in drinking and assuming use of a slimline toilet cistern. I never imagined the levels of domestic waste would be quite so high.

I wish I hadn't figured it out now. That's depressing.

 

[DJE]

It's worse than that. Generally accepted figure is about 150 litres per person per day. Your family above don't seem to bathe or use a washing machine!

 

[WilliamUK]

It's worse than that. Generally accepted figure is about 150 litres per person per day. Your family above don't seem to bathe or use a washing machine!

Couldn't agree more. I considered going into all of that but decided I'd rather just stick to the most immediate daily use things rather than digging around for average use in showers, baths, basins or washing machines. Since everything from bathing to laundry can be done with non-potable water I figured including it would only make it worse, not better so didn't worry too much.


EDIT:
Or perhaps the family have renounced bathing and taken up naturism for some very strange reason. I don't know, I didn't ask them.

 

[DJE]

...snarling criticism.

I expect you're right. Much better to do nothing. Why worry?

There are hundreds of engineers working on the water supply system in the UK. If it was simple as deciding to dam the Arun don't you think we would have done it by now?

To build a new reservoir you need the right catchment area, the right geology, and decent connections to the treatment and distribution system. That's the easy bit, you then have to get it past the planners and the environmentalists. To do this you need to prove that the supply problem is really critical. If it can be managed by occasional hosepipe bans then arguably it isn't.

If you want to see what can be done where the geology is good, the supply problem is critical, and planning and environmental concerns can be neatly sidestepped then google High Island Reservoir and/or Plover Cove Reservoir. (Both in Hong Kong by the way.)

Rainwater harvesting and grey water recycling are both good solutions to reducing domestic demand but the current cost of water doesn't justify the capital required in most cases.

 

[Greenheart]

There are hundreds of engineers working on the water supply system in the UK. If it was simple as deciding to dam the Arun don't you think we would have done it by now?

Rainwater harvesting and grey water recycling are both good solutions to reducing domestic demand but the current cost of water doesn't justify the capital required in most cases.

Those are solid-sounding points, DJE, I apologise for earlier remarks.

I do wonder though, just how (or whether) government policy adjusts to circumstances appropriately.

I believe you - doubtless there are hundreds of engineers working on the supply, but that supply is for tens of millions of consumers - tales of leaks lead one to doubt that anything like enough is being done.

Landowners are understandably reluctant to see their property used/flooded, however benevolent & beneficial the purpose. But that wouldn't make flooding a new reservoir/estuary a bad concept, just hard to sell politically.

And how difficult or unpopular would rooftop-rainwater-harvesting and grey-water re-use be, if Cameron & Clegg promoted it?

That seems to me an obvious way to improve our present downhill trajectory. The current cost of water isn't likely to stay stable if supplies continue to dip. Granted, damming the Arun was a wild idea, introduced as such. But not as totally barmy as my whims often are...

...I've assumed a probably heavier than reasonable use of potable water in drinking and assuming use of a slimline toilet cistern. I never imagined the levels of domestic waste would be quite so high...

...That's depressing.

All that drinking water, used not for drinking, nor any biologically-sensitive purpose, is indeed a shocking waste...

...but...

...is 'potability' the problem, here? I mean, how much of the available non-potable supply, is lost during its treatment to make it acceptable in the mains supply?

Aren't we actually, dangerously short of non-potable supplies? We've surely never been better set-up than now, to ensure plastic bottles of drinking water could be made widely available, for instance in some ghastly emergency...

...but would there really be significantly greater water resources to play with, if we weren't concerned about its being drinkable?

 

[WilliamUK]

All that drinking water, used not for drinking, nor any biologically-sensitive purpose, is indeed a shocking waste...

...but...

...is 'potability' the problem, here? I mean, how much of the available non-potable supply, is lost during its treatment to make it acceptable in the mains supply?

Aren't we actually, dangerously short of non-potable supplies? We've surely never been better set-up than now, to ensure plastic bottles of drinking water could be made widely available, for instance in some ghastly emergency...

...but would there really be significantly greater water resources to play with, if we weren't concerned about its being drinkable?

It's a waste of energy making all that water potable when about 90% of it needn't be.
It's daft that we gear all our thinking about mainstream water resources towards potable water when 90% of it won't be used that way.
There's really no need for many non-potable sources any further away than our own homes. House, shed and greenhouse roofs... bath/shower/wash basin water re-use and so on.

The driest parts of England get about 60cm of rain a year.
Taking my own roof as the national average size (and not caring in the slightest if that's reasonable or not) gives each house in those areas 30,000 litres of perfectly useable rainwater which averages out to 87 litres per day. Wetter areas, like up north, might get more like 160,000 litres a year or more... 438 litres per day. Almost enough to take care of an average family of 4's daily non-drinking water, and that's without using garden sheds, greenhouses or extensions for the collection.

Even in the dry areas of the south, a reduction to between 40 and 50% of current demand on the supply network would have a huge impact on stocks.


We may be short of all supplies just now, but that's based upon the current, entirely faulty collection, treatment, delivery and use paradigm.

It's like saying the tyre on your car is dangerously short of air and so we need to find more air sources... when in fact the tyre has a slow puncture and ignoring the problem and avoiding using your spare isn't helping. We don't need more sources, we need to make use of what we have. The spare is the water that falls from the sky, onto our homes... the punctured tyre is out current paradigm.

Don't worry though - I'm not going to hold my breath.