Low level of water in clay lined pond - how do u use water t

andysgreen2004 · Joined: 04 Jan 2008 Posts: 1

Hi

I completed 3 months ago our long awaited pond. Its around 500sqm in
size so fairly large!

Before we started we had numerous months and discussions with so-called
experts on its location, depth, water levels and other issues
surrounding building or digging a pond!

We dug 3 test holes down into the clay (around 1.2m in depth) and
watched them fill and settle. leaving them for a couple of months to
see what happened. The levels of water in the test holes did vary but
the lowest level was always constant over this time. (if you ignore the
rises after rain!). The lowest level was approx 1ft below grass level if
you can imagine what i mean!

The ground when we then start to dig was made up 1-2ft of top soil,
3-4ft of sand and gravel, and then clay.

We certainly dug more out than we expected, but now have a pond that is
in some paces almost 7ft deep below grass level.

During the dig we discovered a number of land drains all of which were
running into the pond. and this is most likely where our problem is, we
could only find 50% of the land drains the other side of the pond, ie
the outlets. Those we found we dug back and filled with a fair amount
of clay that we dug from the bottom of the pond.

on completion we stood back and wondered at our wonderful masterpiece
and then only had to wait for rain and nature to fill it!

This of course did not take long, being Gloucestershire! and the land
drains running into the pond certainly were flowing!

However the apparent final level of the pond is much lower than we
expected. a good 3-4ft lower than the lowest test hole level we
originally dug.

Even after some rather heavy rain over 3-4 days the level did not rise
above its current point.

which leaves me to believe that i have water disappearing possibly
through some of the land drains we did not discover? or is it something
else?

i am considering how to find the leaking points, assuming that is the
case, and thought water dyes may assist. however i have no idea if it
possible to use water dyes in a pond of this size or even if they would
effectively show me the leakage point? does anyone have any experience
of using them or this situation and can make any suggestions?

I look forward to hopefully hearing your ideas!
thanks
Andy

--
andysgreen2004

Archived from group: rec>ponds

Pond Meister · Joined: 06 Jan 2008 Posts: 1

On Jan 4, 6:28 am, andysgreen2004
wrote:
> Hi
>
> I completed 3 months ago our long awaited pond. Its around 500sqm in
> size so fairly large!
>
> Before we started we had numerous months and discussions with so-called
> experts on its location, depth, water levels and other issues
> surrounding building or digging a pond!
>
> We dug 3 test holes down into the clay (around 1.2m in depth) and
> watched them fill and settle. leaving them for a couple of months to
> see what happened. The levels of water in the test holes did vary but
> the lowest level was always constant over this time. (if you ignore the
> rises after rain!). The lowest level was approx 1ft below grass level if
> you can imagine what i mean!
>
> The ground when we then start to dig was made up 1-2ft of top soil,
> 3-4ft of sand and gravel, and then clay.
>
> We certainly dug more out than we expected, but now have a pond that is
> in some paces almost 7ft deep below grass level.
>
> During the dig we discovered a number of land drains all of which were
> running into the pond. and this is most likely where our problem is, we
> could only find 50% of the land drains the other side of the pond, ie
> the outlets. Those we found we dug back and filled with a fair amount
> of clay that we dug from the bottom of the pond.
>
> on completion we stood back and wondered at our wonderful masterpiece
> and then only had to wait for rain and nature to fill it!
>
> This of course did not take long, being Gloucestershire! and the land
> drains running into the pond certainly were flowing!
>
> However the apparent final level of the pond is much lower than we
> expected. a good 3-4ft lower than the lowest test hole level we
> originally dug.
>
> Even after some rather heavy rain over 3-4 days the level did not rise
> above its current point.
>
> which leaves me to believe that i have water disappearing possibly
> through some of the land drains we did not discover? or is it something
> else?
>
> i am considering how to find the leaking points, assuming that is the
> case, and thought water dyes may assist. however i have no idea if it
> possible to use water dyes in a pond of this size or even if they would
> effectively show me the leakage point? does anyone have any experience
> of using them or this situation and can make any suggestions?
>
> I look forward to hopefully hearing your ideas!
> thanks
> Andy
>
> --
> andysgreen2004

Well it appears what you have is a cut rate dig a hole in the ground
and hope for the best pond. 3 test holes were not even close to
sufficient to tell y ou anything overall, and a series of hles down to
the desired depth should have been dug all around the proposed
perimeter of the pond. I do not know what yu mean by land drains, as
evidently yuor not in the USA, but I assume, they are merely a form of
french drain or ditch filled with rock etc to pick up water and more
it away from other areas..........Its all together possible to dig a
pond in plain sand, and have it hold water if the water table is high
enough,l and 2 if its not, use bentonite clay to seal it all. Your
water table evidently may have been huigher when ytou dug the tests
holes, and it could bhave b een it was much huigher than normal, or
else you have a leak at the max height that yur pond attains no matter
how much rain you get. Its like a built in overflow. Its also possible
this leaky area can silt up and fill in and stop in due time or it
could never seal up. They make a dye to trace water current and flow,
and its easy to mix up and pour along the waters edge near the bank of
the pond and look for any signs of water movement. Its a time
consuming process but it can be done. When and if you find an area
with movement, either dig it out and back fill with good pure clay or
pour in bentonite granuals to seal it. YOu may be able to get a sluggy
truck of mixed well drillers mud delivered by a well driller, and have
them flow it out over the ponds sides and bottom. Its merely mixed up
water and sodium bentonite clay and it will seal up porus or leaky
areas with ease. Try usuing a steel rod and walk all around the pond
an dpush the steel rod (bout a 3/8 to 1/2" diam rod..9-12mm will
work) with a point on the end, and stay back approx 2 feet or so from
the edge. If rod enters soil easy and comes up wet yu can bet there is
a leak in that area. YUO need to concentrate on the level the water
stays most of the time as that is where it seems your leak is at, in
all reality, but it still can b e on the very bottom and any surface
water you get to fill th e pond is merely seeking the level of what is
attainable by the water table...........but at least it will rule out
a leak at the water level it remains at. Flowing well drillers mud
will eliminate any and all of those porous areas and seal em up.

Another method fokls in this region use is to get a trencher and
trench (4" wide will work fine) down about 3 to 4 feet and approx 2 to
3 feet fropm waters edge all around the pond. This needs tobe done
when its not going to rain. If you hit an area that is probably
allowing water to leak through it will start to fill u p that trench.
2 feet of good dirt between trench and pond is more than sufficient to
seal up a pond, so if yu start gett8ing water infiltration in to the
trecnh yuu can see if its flwoing in from pond side or bank side and
you have a pretty decent cutaway view of soil condition from the
trench you made. Finding a leak is doable even if onthe botombut it is
time consuming, and can get expensiive depending on route taken,
Flwoing welldrillers mud in all reality will be quickest and probbaly
give the most satisfactory results for the money. Sodium bentonite is
CHEAP, and if y can get granular clay it can be broadcast over the
pond but flowing a slurry is the best.

L:ots of luck. Check out koiphen.com They have a section that
pertains to strictly mud ponds and have a lot of professional pond
builders that patronize that forum that may also be able to point you
in a proper direction.