On Friday, October 30, 2015 at 12:56:51 AM UTC, jbm wrote:
Right, I'll try to pass comment on all the relevant answers in one go.

Thank you all for your input. The best answer seems to be from Will:
"Basically I think you're ****ed!". Which corresponds very closely to my
assessment!!!

I too (like Alastair) am a retired engineer of the civil and
construction kind. I was asked to look into this because I am one of the
few (if any) people in Northampton who has first hand knowledge of the
local lakes, having been briefed very fully on their design and
construction back in the 1970's. A lot of the work I have done on this
concerns the geology and science behind ground water (N_Cook note - I
have subsidiary qualifications in Geology and Soil Mechanics), though in
a broad sense, not taking into account exact local conditions. While I
was preparing my report for the council, I received a report from an
adjacent local council on the flood assessment of a large housing
development about to take place alongside the stream that feeds the
lakes. I haven't been able to go through it in depth yet, but it appears
to contain a lot of information along the lines I was pursuing. There
are no figures available for the River Nene, which flows through the
county, but at Wansford near Peterborough its level is as low as it has
ever been. Flow rates earlier this year for the River Great Ouse in
Cambridgeshire were about 30% of what would be expected at that time of
year.

One thing I did learn was that the rainfall pattern throughout the year
was not what I expected. The summer months, Jul-Aug-Sep, are on average
about 10-15mm wetter than the rest of the year. Also those 3 months have
the least rain days, which means because of the heavier rate of rainfall
less water manages to get down to the ground water because of its
intensity forcing more in the way of surface run-off.

What I have noticed over the last few years is the numbers of times I
hear reports of torrential downpours to the west of here, whilst we get
next to no or no rain at all. Same applies to the east of us, but not so
noticeable. So it would appear that here in the East Midlands, and
especially in Northamptonshire, all the rain is falling elsewhere before
it gets to us. Never used to be like that - we always got more than our
fair share, not not so these days. Any ideas why that may be so?
Interesting, and somewhat puzzling, that Will is experiencing less rain
up in the hills, whilst Graham reports a slight increase down at the
seaside! Thought that would have been the other way round.

Thanks for those graphs, Len. Although you are a couple of hundred miles
away, they reflect very accurately what we had here in 2011, a very dry
year (60%), and 2012, a very wet year (130%). Unfortunately, most of
that 2012 total fell during thunderstorms, and I reckon sweet sod all
got down to the ground water. Probably more got down there in 2011. As
to water usage, the main reservoir in the area, Pitford, is in the next
catchment area to the west, though it relies on water extraction from
the River Nene to keep it going. Grafton Water is too far away to worry
us. Sywell Reservoir, within our catchment area, was decommissioned some
years ago, so no longer enters the equation. It is now used for purely
recreational purposes (fishing).

So far I have been unable to find any rainfall records for this area
from before 2000. What I have got, however, is a full record of monthly
rainfall since Jan 2006. Since then, by my reckoning, we are about 260mm
= 4% short of what we should have had. Bernard in Wokingham, about 50
miles south of here, has had 20% more. Which sort of emphasises my
belief that something is stopping the rain getting here.

And finally, in answer to Alastair's "So what ever you decide will be
wrong!", no I won't, because after receiving an email earlier this
evening I won't be making any decision in the foreseeable future. I am
stepping back from this for a while. One of our local councillors, much
against the wishes of me and someone I am working with on this, is going
to raise the matter at a full council meeting shortly, and from what we
understand he is going to push for the first lake to be dredged out to
remove the residual pollution and build up of silt. What he doesn't
realise yet (because he has already been cut out of the loop by
everybody concerned over his behaviour on a related matter - his only
interest is in scoring political points over the other parties) it that
silt is the result of a bank collapse alongside some houses, and if it
is allowed to continue or accelerate, those houses will be at risk of
falling down. Our other councillor has been made fully aware of the
situation, as have the Chief Executive and Assets manager of the
council. 2nd councillor has been instructed to shoot first councillor
down by revealing these findings at the meeting and telling him to make
sure of his facts before shouting his mouth off. I wish I could be there
to see and hear it all! I hadn't wanted this to get political, but it is
now out of my hands, for the time being at least.

Well, the general consensus of opinion seems to be no one here has any
bloody idea if we are going to get any rain. Fair enough I accept that,
and is basically what I expected. Will's "Basically I think you're
****ed!" sums it up perfectly.

jim

Northampton-under-Desert

Jim,

I have just come across this paper which you might find interesting:
https://www.researchgate.net/publica...gdom#full-text

Cheers, Alastair.