Tuesday, July 24, 2007

32.78m AOD

That is the height, in metres, that the lowest corner of my house at damp course level is 'Above Ordnance Datum'.

I know this because a few years ago some chappies were at the end of the road doing hard hat/high-vis jackety-type things with levels, and I asked them to give me that measurement.

I figured it would come in handy one day.

Hopefully it still will. I am a great believer in prevention being better than cure, so rather than mopping out the utility room and having a fight with the loss adjuster, I would like to try and make my house as flood proof as possible, against the chance that this 'one in a hundred year event' might happen again next month.

Thing is, I am not off to the best of starts.

The best the Environment Agency floodline could come up with was the offer of a sandbag. Now I am sure they are better than nothing, but I have a few grander plans in mind. Slotted posts with neoprene sleeves to accommodate tapered slats, for one. Quick to erect. Easy to store. With luck, using the best of Junkk.com. Already I have sealed the (now defunct) dryer outlet with a nifty sweet can lid that slid over a treat.

But to figure out what's for the best I need to know what height to make them. And this is proving an effort. I can't seem to get any sense out of anyone so far on what 'might' happen. Which makes planning tricky.

All I have managed so far is to get on a list that sends an email to tell me I'm about to be flooded if I'm in. And a text if I'm out. And as to the brook alongside that is copping the run-off from the new housing estate on the hillside farmland, that's not included as it is another department.

Spiffy.

ADDENDUM - You want some fun? Try getting a definition for Ordnance Datum, much less what it is in your vicinity.

The best I have, so far, is:

chart datum Set reference point on charts for water depth in relation to tides. On metric charts for which the UK Hydrographic Office is the charting authority, chart datum is a level as close as possible to Lowest Astronomical Tide (LAT), the lowest predictable tide under average meteorological conditions (from Ministry of Defence, 1987). This is not the same as Ordnance Datum, the fixed reference point for heights and contours shown on Ordnance Survey maps, which is based on mean sea level (MSL) as recorded at Newlyn (Cornwall) over a seven-year period from 1915 to 1921.

ADDENDUM 2 -

Having signed up to them, I just had an automated mobile call and email to tell me to 'stand down'. So that seemed to work, at least.

Sadly this is not going to help me with the fact that the continued high levels seem to have opened a breech between the brook and my cellar such that the pumps are now working 24/7. I fear I need to get tanking. ££££££££££££££££££££££££££££££££:(

Telegraph - Bogged down with bureaucracy

4 comments:

Dave said...

Are you genuinely serious in saying that they "offered you a sandbag"? As in singular, uno, solitary etc.? A single sandbag would be about as much use as a chocolate fireguard!

Good luck with the self built water defence system - maybe you could patent it - a follow up to the re:tie - the 'junkk:dam'. I trust that the datum that you were given is based upon the normal river level; if so, you should be OK - 30+ metres above normal would be extraordinary!

Peter said...

I knew you'd know neat stuff.

I'd guessed it wasn't above sea level, but wan't sure what it really meant.

Thing is, I can't believe we are 32.87m above the Wye's normal level, for the reasons you say. And looking out the window the drop seems pretty gentle across the park.

But...

In 1998 it was lapping at our front door.

Which is why I am 'on the case': extraordinary times needs extraordinary measures.

Now you have got me in the mood for more second use inventing!

The Junkk.com Dam'n NotGettingPast!

Peter said...

Yup. A sandbag. But looking around some have a few more. Thing is, without proper seals they are next to useless. And with flash floods from the hills, aslwo rise from the river is not the main issue. In fcat waves from cars driving past sreet poling is more serious.

Hence a proper 1m+ slatted, sealed barrier is my plan.

Dave said...

Woooh! Looks like that's above 'Mean Sea Level' (as measured at blah, blah blah!) and probably out of date now anyway.

I would have guessed that Ross on Wye was waaaay above that. How many miles downstream is it tidal? Or does it merge with the Severn before that happens?

Perhaps you have to apply for as many sandbags as you want but only on a one at a time basis? Heaven help us but some agencies really are that ridiculous!