I have a well on my property. I would like to have a computer monitor
the water depth. There are no sensors or anything in the 825 foot well
hole to measure the depth.

What I was thinking is that the electical power used to move the water
from the top of the well water to my tank varies with distance to the
surface of the water.

Is there any device to measure the 220v AC power used to lift the
water, so that I can deduce at least the relative depth?

Thanks for the help.

Regards, ~Steve

In article <1o2ev01014hodbqk9l7r53a5kskosrl2ec@4ax.com>,
stevecalfee@hotmail.com says...
Yes, a clamp-on ammeter will give you an approximate answer.
Just clamp onto one of the AC legs.
If you have a pressure tank, this won't be accurate, as the head will
increase as the tank pressurizes.

My well guy uses a sonar gauge. Fairly low-tech, actually; it used a
bullhorn/PA horn driver, and sent out a low frequency "thump", then
measured time until the echo returned. Requires lifting the well cap,
though.

--Gene

In article <1o2ev01014hodbqk9l7r53a5kskosrl2ec@4ax.com>,
stevecalfee@hotmail.com says...
in which varies from 40 to about 75 PSI as the tank fills. That
change in head pressure is equivalent to a change in water level of
about 60 feet. To get rid of that changing addition to the
energy needed to lift the water, you have to make your measurement
at the same point in the tank filling cycle.

If this is an irrigation well, your head pressure will vary with
the number and type of sprinklers.


What type of resolution do you need? 825 feet is a pretty
deep well, and a 1% power sensor may be difficult to
build. This is especially true in light of possible line
voltage fluctuations.

When you pump a lot of water, you should expect the water
depth in the well to go down unless the aquifer is very
porous.
Mark Borgerson

With most pumps the throughput varies with the presure, so you also have to
measure the flow. The heigth will be power/flow, corrected for the
(changing )efficiency of the pump.

Wim

On Tue, 25 Jan 2005 23:18:06 -0500, Gene S. Berkowitz
<first.last@comcast.net> wrote:

a pressure tank (rubber bladder inside the tank). It would seem that a
ratio between an easily installed electronically readable (after all
it is in the well house) pressure gauge and some power to pump current
measure would give a relative depth. My water level when drilled to
825 feet filled to about 350 feet. So the force required to lift water
was from 350 feet. I really cannot insert anything into the well,
without messing up the pump.

What I would like is a passive method (from the well top) to get the
relative depth. The idea being if I know that at the start of spring
the depth is x, what is the depth the rest of the year? I suspect this
is a general interest question and some analog guy probably has some
method of determining it. I am not that guy.

Regards ~Steve

Hi Steve,

Ok, since I am an analog guy I now feel prodded for an idea. We don't
have a well, else I probably would have tried something already. Quite
frankly I don't know much about wells either. But the first step I'd try
is echo, as one of the other respondents had mentioned.

This doesn't have to be a huge trumpet requiring lots of space. If you
want to experiment try a small speaker, send a short burst from a
function generator and look for echoes on a scope. Play with the
frequency to see what gives the best echo in your situation. You may
need a preamp that is overdrive proof (diodes etc.) and a filter but
that shouldn't be a big deal. The goal is to isolate the echo so well
that detection is sufficiently secure.

If that works and you want to build something more permanent post again
and we can share more ideas. Basically then you'd have to find a speaker
plus maybe a microphone that won't corrode easily and equip your receive
chain with a 'range gate'. That is a gate which blocks echoes from
unreasonable ranges, for example for the first couple hundred feet and
then past the bottom of your well, to prevent multiple path returns from
being detected.

All this is very similar to ultrasound equipment.

Regards, Joerg

http://www.analogconsultants.com

Steve Calfee wrote:
When the pump is not running, does the water in the line recede to the
level in the well, or does the line stay primed?

Could you simply time how long it takes for the water to reach the tank
when the pump is engaged? If it takes the pump N seconds to deliver
water to the surface, then referencing N against a scale (either
calculated or benchmarked at different levels) would tell the rough depth.

If the water in the line drops when the pump is off, and if the air in
the line is easily evacuated by the pump when it engages, then the tank
bladder would not apply any back-pressure until the water reaches the
tank. So, the level of the tank would not be a factor.

From the proposed sonar solutions, it sounds like the line recedes to
water level when idle, so maybe this scheme could work?

Steve Calfee wrote:
If you have a means of placing a virtual electrode at the water
surface, you might be able to measure the ohmic resistance from
there to the pump, and thence the ohmic resistance from the pump to
the wellhead. To do this you need a conductor down to the water
surface, which might be a steel casing. I would assume from the
pump up is a plastic pipe, which can insulate from the surrounding
water. Of course the water conductance depends on the impurities,
which may or may not be constant.

If you can get an ohmic reading between the casing at the surface,
and the returning column of water, and my insulation assumptions
are right, that should be some sort of calibratable value. Maybe.

--
"If you want to post a followup via groups.google.com, don't use
the broken "Reply" link at the bottom of the article. Click on
"show options" at the top of the article, then click on the
"Reply" at the bottom of the article headers." - Keith Thompson

One way might be to drop a water-pressure gauge to the bottom of the
well. The weight of the column of water on top of the gauge can be used
to calculate the height of the column.


CBFalconer wrote:

On 26 Jan 2005 21:03:41 -0800, diablovision@yahoo.com wrote:

Or if the pump is located at the top of the well, mount a pressure
sensor to measure the suction. This would be inverse proportional to the
water level.

Tom
---
Email: tom@twist.no (lb8x@qsl.net)
Phone: +47 35972928/90662366, Ham call sign: LB8X Locator: JO49UA
Snail: Tom Twist, Kirkeveien 8A, N3970 Langesund, Norway

Tom Twist wrote:

I don't think you can put the pump there with an 825' well with water
300 odd feet down. The pump is holding up 10 atmospheres or so (I assume
the pump floats on the water, rather than pumps from the bottom all the
time). A tough pressure gauge down there might help. Otherwise an
automated stone dropper and ear.

Paul Burke

"Tom Twist" <tom@twist.no> wrote in message
newsnhhv0tf6qi0t1km5rl6i0fpketdv1o761@4ax.com...
His well is 825 feet deep. You cannot suck water up to more than the
airpressure's worth of water column, which is 10 meters or 33 feet. So there
is no pump at the top.....

Meindert

On Wed, 26 Jan 2005 20:58:51 -0700, "Richard H." <rh86@no.spam> wrote:

Typical installation of submersible pumps includes a checkvalve at the
pump. The entire feed line from the pump to the tank remains full of
water and pressurized at the tank pressure. As soon as the pump
starts, the water begins to flow immediately. There is to time lag to
measure.


-Robert Scott
Ypsilanti, Michigan
(Reply through this forum, not by direct e-mail to me, as automatic reply address is fake.)

Meindert Sprang wrote:
pump at the top of a well that is deeper than 33ft. Check out "jet
pumps" for details. Basically, a jet pump uses two lines to pump the
water in a loop, at the bottom of the loop, is a venturi. The "low
pressure in the venturi sucks more water into the system. Neat trick. I
used one of these for years.

Tom Twist wrote:
Suction pumps fail slightly before the 800 odd foot depth
specified. I think the OP specified no in-well sensors were
available.

--
"If you want to post a followup via groups.google.com, don't use
the broken "Reply" link at the bottom of the article. Click on
"show options" at the top of the article, then click on the
"Reply" at the bottom of the article headers." - Keith Thompson

While I agree that the OP said no "in well" sensors were allowed, I just
thought of another clever way to measure the column of water.

Consider a tube running down to near the bottom of the well, with the
bottom of the tube open to the water. Now, slowly introduce compressed
air into the hose. The air will displace the water until the air starts
bubbling out of the bottom of the hose. The air pressure (PSI) will then
become constant. That terminal air pressure will correlate to the depth
of the water column that was forced out. No? (i.e. it easy to blow
bubbles in your glass of water, but harder to blow bubbles at the bottom
of an 800foot well)

Sure, you'd have to make some adjustments for the "weight" of the air,
etc, but considering the relative densities of water and air, I suspect
these could be ignored.

- jim

CBFalconer wrote:

In article <41f8dd17.520050@news.provide.net>, no-one@dont-mail-me.com
says...
solenoid to tap the pipe supporting the pump and listen for echoes.
You should get an echo at the point where the water in the well
changes the acoustic impedance of the pipe. The speed of
sound in steel is about 4500m/second. If you can detect echoes
with 250 microsecond resolution, that would give you about 1-meter
resolution in depth. The pump itself should give you another
(and stronger). That echo could be used for auto calibration
if you know the length of pipe to the pump.

Detecting the echo might be an interesting DSP project--you could
capture a representation of the outgoing pulse, and use auto-correlation
to detect the return. A bit of research on sonar and ultrasound systems
seems in order.

Mark Borgerson

On Thu, 27 Jan 2005 06:38:30 -0800, jim w <jim22@trlp.com> wrote:

Bubblers are a well-established depth measurement technology that has
been used for years. The trouble with a retrofit situation is that it
is hard to get the darned tube down there, past the "pit-less adapter"
(any well-buffs out there know that term?)

Personally, I like the echo method. If it is done right, it can
siphon power from the AC line during pump operations, and then used
the stored energy (maybe in a supercap?) when the pump turns off (so
that things are quiet). The results could be sent back along the AC
line using one of the low-bandwidth data-over-power-line technologies.
Gee, if it weren't so darned cold here in Michigan I would be tempted
to go out and try some experiments on my well right now :-)


-Robert Scott
Ypsilanti, Michigan
(Reply through this forum, not by direct e-mail to me, as automatic reply address is fake.)

On Thu, 27 Jan 2005 15:50:40 GMT, no-one@dont-mail-me.com (Robert
Scott) wrote:

Wow, some pretty creative methods. Yes it is a deep well. The pump is
down some 800 feet in a 825 foot hole. Only the top 40 feet or so are
lined (to prevent ground water from leaking in) with metal and cement.
The hole is in mainly rock. The pump is on a 2" pvc pipe, with
electical wires hanging free in the well hole.

When the pump goes on, the energy required to lift water is from the
surface of the water in the well, not the pump. That is why I thought
a ratio of energy used in pumping relative to the pressure in the
surface tank system. I believe the pressure in my tanks are related to
the pressure all the way down to the pump. And yes, I believe there is
a reverse flow preventer down by the pump.

Remember in rural areas everyone has wells. As far as I know noone has
a means of measuring water level (at least in non-industrial -cheap-
use). Wells do go dry, especially at the end of summer in dry years.
If there was warning that a well was low, restrictions of use would be
possible. A good enough solution does not require a real time
measurement, once a day or once per pump use would be much better than
never. An absolute measurement is also not required, relative
measurements done over time would also give information about well
health.

A real-time measurement would allow evaluation of the well recovery
time. When water is pumped out, the well fills through cracks in the
rocks. If the pump goes faster than the fill, the water level will
sink during use.

Regards, ~Steve

jim w wrote:
Classic oilfield technique. Extremely precise
measurments can be made if you use helium instead
of air/nitrogen and if you carefully compensate
for the temperature and density of the gas.

Probably not practical for a 800 foot water well
without the capillary tube.