A Tale of Two Reservoirs

What a weekend.  We spent much of it huddled by the fire in Herbie while the rain lashed and the gale blew outside. However we did venture out on your behalf to see if all this rain is doing any good canalwise.  The water level at our mooring is certainly up a good three or four inches, and as that’s on a twenty mile pound, that’s a lot of water.

The red boards are out all down the Thames, the radio reports flooding all over the place, surely this is going to make up the canal reservoir shortages. On Saturday we braved the weather  out to look again at Welford reservoir.  You may recall that when I posted my last picture of it, only about a month ago, it looked like this.

Well on Saturday it looked like this:

Not full by any means, but coming along really well.  A couple more comparisons:

Before

After

I think that might mean it’s now three metres deeper!

So is it time to call off the restrictions and plug the hosepipes back in?  We decided to do another check on the way home today, and diverted via Marsworth to see the situation at Startops reservoir.  Dodging the puddles in the car park, I was optimistic as we approached the steps up the reservoir bank, which by the way was covered in huge numbers of dandelions.

Up the steps and over the top, and I have to admit our hearts sank.  This is what we saw.

Doh. As you can see it has a long long way to go

It hardly looks better than it did in January.

There might be water gushing down our rivers, but that’ll all end up in the sea.  The reservoirs and aquifers tell a different story.  So don’t complain yet about rainy weather, we still need lots more.

Canal Rain Monitor goes live

I am now receiving regular rainfall readings for the Leicester summit area.  The new non profit making (you’d better believe it) weather station supplying the figures has been established at Long Buckby (not far from Norton Junction) by a Mr Rick Bunnage who wishes to remain anonymous.

Using a sophisticated lemonade bottle in his garden our anonymous benefactor has reported a rainfall of 33.3mm over the last week.  It doesn’t seem a lot for such showery weather.  I have asked him to try harder in future.

However, little as the rainfall seems, even that much  rain falling onto water surface of the 20 mile summit pound should allow more than 60 extra boats to pass through the locks.  Whether much of it is getting to the reservoirs I can’t say.  I suspect the dry ground is soaking up much of it.

Changing the subject- in response to a request flooding in from a Mr Halfie of Norwich  I have created a new page (see links on the right) called Gadgets,  into which I have put a circuit diagram for my electronic dipstick water level gauge.  CAVEAT EMPTOR – this has as yet got no further than a prototype, so who knows if it will work in situ!

Not for the faint hearted

Blimey, what a tangle.  My latest project for a Herbie gadget is much less complicated than it looks.  This is just a first prototype. That little black chip has 18 things connected to it, hence the tangle, but all it really amounts to is four switches to turn on the four green LEDs when those five  loose dangly wires pass a small current.  The danglies  are all submerged in water.  The dangly on the right connects to the plus side of a little pack of four AA batteries.  The others pick up the current through the water and as they do, the switch lights up the lights.  Dipping  the wires in a jug of water it appears to work.

If I ever get it finished it might look more like this

Its a water tank gauge.  The wires will be cut to lengths so as to contact when the tank is 1/4 full, 1/2 full and so on and the little lights will come on accordingly. Its really an electronic dip stick.

The hard bit comes in trying to get a neat circuit layout on a bit of copper strip board.  I’m thinking of attaching the danglies to a bit of thin plastic pipe to keep them straight, it only needs to be about half an inch diameter.  Then I have to decide whether just to drop it in via the filler cap, or permanently fix it through a hole drilled in the top of the tank. The latter would be better as I wouldn’t then have to withdraw it all when we are filling the tank.

I imagine it will end up costing about £2.50 for the bits.  Add labour costs at the minimum wage and the end cost will be about £500!!  I am a slow worker.

Still, it keeps me off the streets

Reservoirs - latest figures

BW have published their April reservoir watch data, so I’ve updated my graphs.  It appears that what they call the April figures are those until the end of March, so all this lovely rain we’ve had lately won’t show until next month.  Nevertheless despite what they claim is the driest March since 1953, there is some slight improvement.  I think this may be in large part due to the restrictions and pumping measures introduced.  This time last year, the figures took a downward turn, but this month they have gone up, with the notable exception of GU South despite the Tring summit restriction.



The K&A continues to be very erratic.  Can anyone explain this?  I hope it’s not their measurement equipment on the blink!

I have high hope for the May figures.  Let’s hope this pluviosity* makes a difference.

Interestingly there are a lot of reports lately about low levels in rivers.  Of course they may well temporarily swell with the rain, but rivers don't hang on to their water as well as the canals do.  Could it be that later in the year, those of us on canals may be better off than those on rivers?  Food for thought for boaters who have headed for the rivers to avoid the canal restrictions!

* I thought I might have made that word up, but I just checked and it exists!  Raininess.

A scientific discourse on tunnel rain.

I told you I have a friend, PDS, who knows everything*, and to prove it, read on.  Rick alerted him to my post about tunnel rain and in due course we have this erudite reply.

A tricky question.

If condensation, then whether it rains on you depends on the morphology of the tunnel roof lining. If the roof were smooth, like a glazed clay pipe, the water would just run down the sides. If stone with mortar joints, then water will drip off every joint. Has Neil made a study of canal tunnel roofs as he 'legs' through them?
Crick tunnel is in the Lower Lias, which is normally thought of as clay. However there are plenty of beds of permeable material in it, so Neil's idea that water could permeate through certain layers is entirely sound. It would worry me if there was much water flow. The water could scour out clay and other loose material from just above the tunnel lining and lead to a collapse.

The Lias typically contains iron pyrites, FeS2, which oxidises on exposure to atmospheric oxygen to give the brown/red colour of iron oxide and SO2 (which would normally dissolve in the water). If oxygenated water passes through the Lias you could get acid water akin to acid mine drainage. Then the lime mortar in the tunnel lining could be dissolved.

It all sounds rather hazardous. I would advise Neil to avoid the tunnels. He should study the maps to find convenient bypasses! Alternatively he could 'leg' really fast so as to minimise his exposure to risk.

*Well nearly everything, although I suspect that his references to legging may be ironic.

Thanks Pete.

Of Gunwales, Yoghurts and Not Wasabi

I have to keep my mouth shut a lot of  the time when I meet up with folk on proper working boats for fear of putting my foot in it.  I just haven’t learned the lingo.  I don’t know a snubber from a snatcher or a Joey boat from a Tom Pudding.  I believe the latter may be some sort of cat based dessert.

Anyone who has met me will know that I don’t speak in BBC English.  Actually being a native of South Worcestershire, there is one BBC programme where I would have an authentic accent – The Archers.  However in writing  I do like to get old words right, preferring to write gunwales rather than gunnels, and I am pleased to say that at least one of my kids has followed suit.  Our Richard – himself a liveaboard narrowboater refuses to buy yoghurt if the tub calls it a yogurt.  Sadly he is running out of options on this front and down to only a couple of makes.

Where is all this leading? You may ask.  Well, see if you can work it out from this email which I was pleased to receive from Richard yesterday.

“I don't know how regular an occurrence it is for the Countdown Conundrum to go unsolved by contestants, audience and hosts alike but I got today's well within time and so would you have.

And here is today's conundrum

NOTWASABI

Tick-tock, tick-tock, tic-tock, tick-tock, doong, doong, doong, doong, doong, doong, da-da, da-da, da-da-la-da, beeeeeuw!
and the answer is.....

BOSUN

That's a proper bit of conundrumming for ya! “

If you can’t work that one out, you don’t deserve to.

Little boxes

Not made out of ticky tacky, but of some mahogany offcuts I have lying about.  These two you see below are nearly ready for installation aboard Herbie.  This first little one contains a piezo beeper and an LED and will be mounted just inside the rear hatch so when it flashes and beeps the steerer will hopefully see and hear.

This second larger box will house Herbie’s Smartgauge battery monitor (it drops over and into the the big square hole)

and the little electronic circuit you see here.  The box does have a base – but I’ve removed here so you can see inside.

We’ve had our Smartgauge for a long time now and it really is good at monitoring battery capacity and state of charge.  However, until now I have not enabled the feature which enables it to trigger an alarm if the batteries go outside of their healthy voltage range.  Most of all I worry about overcharging because we now have sealed domestic batteries and if they boil off water, I can’t top them up.  Since we’ve had the solar panel this is an occasional problem after a few hours cruising on a sunny day.  The Smartgauge flashes “E03” because the voltage has risen beyond 14.5 volts.  However, because the Smartgauge is located where I can’t see it when steering, I don’t see the error message.

So this is what these new boxes are all about.  Thoughtfully, the Smartgauge has a relay switch which closes when the warning condition occurs, so al you have to do is connect a lamp or buzzer to it (and a battery) and the lamp or buzzer will come on.  Just because it’s more fun to do I chose to make this little 555 timer circuit which will pulse the flash and beep about once a second.  There will of course be a cable between the two boxes.

The hardest bit was the little buzzer box –yet to have its coats of varnish..  I didn’t think I could make a good one out of individual bits of wood – too fiddly and I am not a cabinet maker.  So I used a solid block of wood and chiselled out little holes and grooves to hold the buzzer, the LED, a resistor and the wiring.  Amazingly I still have all my fingers.

Tunnel rain–some answers, well theories anyway

Two people have offered theories about rain in tunnels, and in a flash of the blindingly obvious I have just thought of another.

My good friend David, aka Rainman – who sent in a reply on the wrong post (Doh)- reckons the dripping in Crick tunnel is seepage from ground water running down through a permeable layer underground and moving downhill over a non permeable layer.  He is probably right and I may find out for sure on our sailing weekend next month when I hope to be joined by another old friend PDS who does in fact know everything, especially about geology. (and cement).

Which means I have to doubt the word of another kind contributor Bobr, all the way from N Carolina who reckoned it was condensation.  Sorry Bob.  What leads me to this conclusion is that there are a fair few canal tunnels of similar length, but they have widely varying amounts of rainfall inside.  Some are virtually dry, whereas Crick in particular is very wet. 

Which leads us to the question, why are some tunnels wetter than others? For example Husbands Bosworth tunnel, not far from Crick is generally bone dry.  Can it be to do with air supply? I don’t think so, although that one is 1100 odd yards long and Crick tunnel is nearly a mile.  Interestingly I haven’t noticed any air shafts in Crick tunnel.  Air shafts generally make good waterfalls as anyone going through Braunston tunnel will testify.   Is the geology at HB different from Crick?  Possibly but I have a better idea.

Tunnels have been built by all sorts of engineers over the years and many of them have been repaired and relined since.  Could the variation in wetness simply be due to how well the tunnel was lined?  I reckon that might have a lot to do with it.  Some of them just keep the water out better.

But, going back to where this all started, I’m still amazed that Crick is still dripping after 20 odd months with hardly any rain!

Great Imponderables of the canal system: 1

Unlike Stephen Fry, there are several things I do not know.  One of them is this: Why does it always rain in Crick tunnel?

You can tell experienced boaters as they pass southwards through Crick –they are putting on their raincoats on a sunny day. After goodness knows how many drought months we have had, if you go through that tunnel today, you will get more than a drip or two down your neck.  Well that was true a week ago at any rate because I was there.  In Crick tunnel it rains every day of the year.

Now that bit of the canal is the highest watercourse in the area.  It is the summit section that feeds downhill at its ends through steep staircases at Watford and Foxton.  Admittedly the ground does rise to the east , but only by some 20 metres in a mile or so and then it goes downhill again.   To the west is a similar rise about half a mile away. Here’s my artists impression (O level Art grade 5 1964, second attempt)

Here we see the tunnel mouth as approached from the north.  Can it really be that that measly bit of ground over the top has held enough of its own water for a dry 18 months to still be dripping into the tunnel?  It could be coming downhill from  the left of the picture, but there isn’t that much land up there. 

Short of there being a leaky pipe up there ( I doubt it) I can’t think of any other explanation.  But it still amazes me that there is enough water up there to make continual rain in the tunnel.

Or could it be condensation??  It is pretty cool and clammy in there.  Maybe that’s it. 

We should be told.

Archimedes to the rescue

It is a truism that in DiY, you get a job right the second time you do it. Last autumn I wrote, somewhat smugly I expect,  about how easy it was to repack Herbie’s stern gland.  Well, it was, but I obviously didn’t do it too well because it has been dripping too much, so I decided to have another go.  At least I have lost my fear of water gushing in during the process, because it doesn’t.

I think the reason it was still leaking was that I didn’t cut the lengths of packing sharply enough, leaving frayed ends through which the water can seep. So this time I decided to adopt the alternative Tony Brooks method.  This I think is what Tony does himself, but as it is unorthodox he reminds us that it is “at your own risk”.  The idea is to use a single long length of packing wound helically round the shaft rather than the conventional three or four separate cut rings.  This eliminates the cut joints, but you have to do it right because the helix of packing rope forms an archimedean screw pump as the shaft turns.  Wind it on the wrong way and it could pump water into the boat rather than out.  Of course you might get some leakage when in reverse, but that isn’t usually something you do for more than a minute or two.

Anyway, that’s what I did and it does seem a lot better although I expect I’ll have to adjust up some slack after it beds in.

Excitement all round

Despite the drought, (actually it’s raining as I write –hooray!) we are in a state of some excitement about boating this summer.

I believe the Queen may quite excited too if her minions have informed her that Kath and I will be accompanying her on her Jubillee cruise down the Thames in June.  Admittedly not on the same boat (a tinge of disappointment for her there), but on board Nb Indigo Dream.  Yes, Sue and Richard have generously invited us as crew on the big day, perhaps because we didn’t panic when it got a tad choppy during the trial rehearsal last year (remember my pic of NB Leo looking as though it was about to dive like a submarine).    I believe there will be 998 other boats there too, but I don’t suppose anyone will notice.

The organisers seem to be leaving nothing to chance, having recruited King Canute (well, the Thames Barrier), to stop the tide for a day, a precaution I am very grateful for, having seen how fast the tide can rip through London.  We have had to fill in security forms with the sorts of details you might have to disclose when applying for a job with MI6.  Even now I suspect that we are under constant surveillance from the house opposite and I’m sure I saw a frogman bob up behind Herbie on the Leicester arm recently.  On the form, we had to declare our role on the vessel.  It was decided between us and Richard and Sue that putting me down as tail gunner or munitions technician might fail to rouse the security staff sense of humour, so we settled for crew assistant or some such.  Thinking about it afterwards I would have liked to offer myself as “oiler” which is a splendid job title often seen on old steam ships. 

However it’s not all good news.  There is a strict alcohol ban for the day, including 8 hours before the event! Well everybody has to be a hero sometime.

We get extra treats too, for we have to attend tideway rehearsals during May.  If they are anything like last year’s they should be enjoyably chaotic.

Our own organisation for that period is somewhat less thoroughly planned and we have a lot to fit in.  It is the same weekend as Crick Boat Show and as we have free tickets and Herbie is moored on site we will be attempting to do the show and the Jubillee pageant.  That leaves us with the small matter of getting from Crick to Canary wharf for six am on pageant day and then back again for the rest of the show.

In the weeks prior to all that we also have to fit in our annual sailing weekend on the Norfolk Broads, and then in the week before the Crick show and the pageant, we will be guest crewing on another well known boat, for we’ll be giving Adam a hand in bringing Briar Rose up to Crick from his new moorings at Thrupp wharf.  No not Thrupp on the Oxford.  This one is just north of Milton Keynes on the GU.  There are quite a few heavy locks between there and Crick, not to mention the Watford staircase, so the poor lad needs a hand as Adrian is unavailable.  Actually we’re looking forward to that too.  A chance to work on a superior vessel to our own.

So that’s May and June boating for us – all on other people’s boats.  Herbie will be getting jealous.

Reservoir level charts

Here’s something to freak out all you data freaks.
 
They say a picture is worth a thousand words, so I used BWs reservoir watch figures to produce this chart,.  I suppose it just tells us what we already know –that there ain’t enough water for the time of year.  The graphs cover the period from January 2011 until March 2012.  The vertical axis shows the percentage fill level of the reservoirs for the canal groups listed. 

What it shows for the Grand Union in particular, is that over the course of last year the reservoirs used up between 70% and 80% of their water, and over this winter we have only put 25% back.  Now that the boating season is under way, we should expect the graphs to turn downhill again albeit at a lesser rate because of the restrictions in place.  Unless we get a lot of rain, it all points to closures by late summer.

A bit about the canal groups:

GU is a bit complicated as it is in three bits – the OXF/GU line covers the Oxford canal and the GU in the Braunston area.  It’s interesting to see that the three GU lines follow pretty much the same course, although the GU north seems to have changed more significantly.

Kennet and Avon looks a bit erratic doesn’t it.  I wonder why that is.

I included the Shroppie/ Staffs & Worcester area mainly to show the contrast once you get north of Brum.  They’re actually better off now than a year ago.  I haven’t shown northern canals such as the Leeds and Liverpool because the chart is getting a bit crowded, but suffice it to say their reservoirs are full!

Never Mind. Rick tells me it rained well in Buckby all day yesterday. That’s the spirit!

Avon calling

There are an alarming number of river Avons, mostly because Avon is an old word for river. Here we see The Avon at Welford, which confusingly is nothing to do with Welford on Avon which is near Stratford.  Same river though. This picture is taken at Welford Northants where the Avon is just a couple of feet wide and six inches deep  ( I think that might classify it as un navigable) and is very close to its source. It runs within a few yards of the canal basin, and   I bet like me, a lot of people mistake it for the reservoir feeder to the canal.  However, it never touches the canal although it continues parallel to the summit of the Leicester line for some miles before peeling off towards Warwick. 

So now you know which Welford is which.  Or do you?  Disconcertingly, there are as many Welfords as Avons and to add to the confusion, one of them is close to the Kennet and Avon canal !  That of course refers to a different Avon, the one that goes out through Bristol, and not the one that rises on Salisbury plain and goes down to Christchurch.  Are you still with me or have you lost the plot by now?

Anyway, I was very happy to find this little stream at Welford because it reminded me of the many happy hours (well years actually) I wasted on the banks of the Avon near Evesham in my youth.  That’s why I called it The River Avon.   I should have dropped a little paper boat onto it at Welford with a message for my brother who still  lives close to the Avon at Offenham. 

I wonder, as everywhere is so dry, where the water comes from, because the little stream had a reasonable flow on it.  Springs I suppose, although I can never work out why springs emerge on high ground.

Anyway next time you are boating through Stratford upon Avon, or down through Pershore to Tewkesbury you’ll know where it all starts.  Make sure you’re on the right Avon though.

Foxton condolences

I’m not sure how you condole a dog, but at Foxton museum it would appear to be obligatory.

When we were at the locks last week I roamed about with the camera trying to capture a sense of what a lovely evening it was.  Quite hard, as the middle distance was quite hazy.  The low sun really picked out the ridge and furrow patterns on the adjacent field.

Standing at the top of the locks you really do a sense of the plunge you take going down the hill to the junction .

The locks have well kept side ponds all the way down and the reflections in this one caught my eye.

Leicester summit pictures and the tale of the Welford pumps.

Back home now with a chance to sort the photos I couldn’t post while we were out.  Here’s my favourite

According to Nicholsons, this bank is the site of the medieval village of Downtown or Downton.  Quite Hockneyesque don’t you think?

Here is one of our buzzard escorts I mentioned last time.  I wish I had a longer lens!

Then, surprise surprise, some water actually flowing into the canal in between Welford and Foxton!  I haven’t got a clue where it comes from but every drop helps.

Up on top of the world at Welford, they currently have two pumps picking up water from below the solitary lock and depositing in the upper arm to keep the boats afloat in the basin.  They also have another pump at the end of the basin feeding a long pipeline over the hill and into the reservoir. 

 

So If there is sufficient water they can actually fill the reservoir from the canal (In thought it was supposed to be the other way round!).  The day we were there, that particular pump wasn’t running and the end of the pipe lay forlorn.

 

Local rumour has it that  BW originally put a higher capacity pump at the basin than they had at the lock, so the basin kept running dry because the lock pump couldn’t keep up.  This was the cause of a badly worded restriction notice from BW warning that the lock might be closed at times in order to top up the basin.  Now it seems they have got the pumping the right way round and the lock is open all the time.

The reservoir, although a little fuller than when we were there in January is still very very low.

In fact, if I have read this gauge right, more than three and a half meters below the full level.  That’s over ten feet in old money.

Next time I’ll sort out some images from Foxton.