Monitoring water depth in a well?

dcyrilc · Jan 31, 2010

I was reading in another thread, when the topic of wells came up. This reminded me that a while back I had been looking for a way to monitor the water depth in my well and never found anything to do what I wanted.

I have a 350ft well shaft, which when finished, the water stabilized 13ft below ground level. During the initial testing of the well, it drew down to 75-100ft relatively quickly then leveled off. We hung the pump 150ft down the shaft.

After our well was completed, I met several people who had wells go dry during extra dry summers and I began to think it would be nice to have a digital readout in the well house which told the water level in the shaft. I searched on line for a year or so and never found anything and basically forgot about the idea until the other day.

A few people expressed interest in this idea, so I have decided to start this thread to draw upon the wealth of information available through the users of TBN.

For myself, since I am not present at the well house very often, an audible alarm could go weeks without being heard. I hope I can find a way to have a digital readout in the well house for when I am there to look at and check, but also to be able to remotely monitor it via IP from a computer. All the buildings on my ranch either have IP there via the LAN or have pathway for future installation.

This thread is intended to be open to any type of monitoring system so that myself and others can have access to the information as to what is available in monitoring systems for their wells.

Egon · Jan 31, 2010

Heron Instruments | dipperLog Groundwater Data Logger

Something like this.

dave1949 · Jan 31, 2010

I wonder if there is a pressure transducer that would measure psi at the bottom of the well. The pressure could be translated to the depth of water in the well.

For example a pressure reading of X equates to a depth of Y.
Dave.

dcyrilc · Jan 31, 2010

dave1949 said:
I wonder if there is a pressure transducer that would measure psi at the bottom of the well. The pressure could be translated to the depth of water in the well.

For example a pressure reading of X equates to a depth of Y.
Dave.

That's what I would expect, but does anyone make it and does it interface the way I would like?

TheGoose · Jan 31, 2010

Of course there is, this would be very easy to do in an industrial setting. Not sure how a homeowner would accomplish it in a cheap and efficient way.

In an industrail setting to measure the level in a vessel you have two legs at different depths. The lt (level transmitter) can measure the difference in pressure between the two points and give you level in inches of water or whatever you calibrate it to. For a well you leave the high leg in air and put the low leg at the bottom of the well (or whatever depth you call 0). It will measure and display the level according to how much pressure is on the liquid leg.

dex3361 · Jan 31, 2010

The simplest and most readily available to give a contact closure is a resistive sensing probe it would close or open contacts when the water drops off of the probe. The issue that will be apparent when researching is the cost of the equipment. If you have the money it can be done. There are a few other reliable ways to do like a home made bubbler system that you read a gauge. Here is a link to USA Bluebook it serves the water industry. The section I have linked is for level indication. Google Bubbler water level indication.
http://usabluebook.dirxion.com/dialup/

dave1949 · Feb 1, 2010

This company provides two forms of interface output, don't know if you can use them easily or not. I am guessing the simplest way would be to have a plug-in card in a PC with some scientific instrument software. You would think someone sells a kit that includes a wireless unit similar to an outdoor remote weather station. Thats what you are looking for I think. Seems expensive, but if it saves a couple animals, probably isn't.

There are numerous hits if you google 'water pressure transducer'.

Water Level, Stage, & Flow Sensors: Pressure transducers, bubblers, shaft encoders, ultrasonics

Dave.

Highbeam · Feb 2, 2010

I've seen it done with an air tube attached to the pump down in the well. You add air pressure to the tube until the pressure doesn't go up anymore. Measure this pressure. The depth of water above the pump can then be easily calculated. 20psi = 46 feet of water.

The Dougster · Feb 2, 2010

As Highbeam suggested, the airline method is most often used with public supply water wells... It isn't complicated but one must know the length of the tube in the well...
It's a good idea to keep an eye on the static water level but to monitor it constantly might be a bit of overkill. State and Federal folks normally use a graduated steel tape. Chalk up 20-30 feet with carpenters chalk and lower it into the well. The chalk makes the wet tape much easier to see. Subtract the wetted portion from the total amount you lowered into the well and that is your water level.
All that is assuming you have a well that is cased to the bottom. In open hole completion wells, water tends to wet the tape making an accurate measurement difficult.
There are devices known as E-Lines (Google it) that are relatively inexpensive. They are battery operated and when the probe reaches the water, the circuit is complete and a small alarm will go off....
Unless you're in a vuggy and fractured formation, it is highly unlikely that you will see significant change in water level on a daily, weekly or even monthly basis. Check with your Dept of Natural resources and see if they have groundwater data available. Often they have water level monitor wells, which you can use to calculate your approximate water level using land surface elevations.
I used to do this for a living and would be happy to help if possible.

dex3361 · Feb 3, 2010

Highbeam said:
I've seen it done with an air tube attached to the pump down in the well. You add air pressure to the tube until the pressure doesn't go up anymore. Measure this pressure. The depth of water above the pump can then be easily calculated. 20psi = 46 feet of water.

This type of system is called a Bubbler system if you google it. The pressure of water is 1 pound for every 2.31 Feet of water column or .43 psi per foot. The bubbler system is accurate and reliable. The pressure of the bubbler could fee a 4-20ma transducer/transmitter and input into a RTU (Remote Telemetry Unit). I can and is done all the time if you have the money. The bubbler system could economically be installer to visibly check the depth as the others have stated using a gauge instead of a transducer.

tshep · Feb 11, 2010

If I may offer...I doubt you really want an air pressure, or vacuum operated system - that's an additional device to install, run, and maintain. If you have a pump, you already have electicity - that's probably all the utilities you need.

Think if you really need a constant monitor of variable level, or just to know if the level is blow a certain point. Mostly, sensing of a point is much cheaper than determining a range. Based on what you wrote, may be 170 would be good control point - at that point you control the people (usage) until you're back above (and at that time you would know level was on the low side and it would be time to physically check more often.)

HVAC systems often have a low voltage moisture sensor for upstairs units - to detect before the condenser is overflowing to the ceiling - cheap and safe.

For just convenience sensing, I believe I would try a weighted float first - on a string, to a pivot arm that would raise a flag against a light spring - a remote-view version of the dip stick methods. Easy to design and test on the bench, and then just add a longer string.

I missed that IP part - that would be a long string, wouldn't it?
Something you could do is just supply or remove power to something that has an adjustable address - a switch signal (however developed) makes or breaks an old router or modem that has an unusual address - say 192.168.11.11 - if you can ping it on the network you know the water is high or low, etc....

dmccarty · Feb 11, 2010

I too have wanted to be able to measure the static water depth in the well but never really looked that hard.

I was a bit concerned about the static water depth a few years ago when we where in the middle of a multi year drought. I googled and found a website that had well water depths over time for wells around my state. Even during a very bad drought period the well depths had dropped about 10%. Our well has 223 feet of water in it so to loose 10% or even 20% is a who cares. There was a shallow 36 inch diameter well in Chapel Hill that had not lost much water which surprised me.

Search the Internet for well water monitoring in your state and see what shows up. I think some of the wells were based on Federal data but I can't be sure.

I still wish I had a little gauge showing the water depth.

Later,
Dan

Iplayfarmer · Feb 11, 2010

It sounds like the biggest challenge is getting something that can be monitored remotely. The easiest and cheapest methods (bubbler, chalk stick, and string with flag) don't lend themselves well to remote monitoring.

I guess worst case scenario you could put a remote camera looking at a gauge.

Redneck in training · Feb 16, 2010

There is a device called displacer. The beauty of it is relative simplicity and that the sensor is above ground and easily accessible. The displacer is an object (in example sealed 1/2" cooper or plastic pipe) hanging on a spring in the well. Because the volume of the displacer and specific gravity of water are also known it is easy to calculate the force extorted on the spring depending on how much water it displaced. The change in length of the spring is the measure of the water level change. Since the device can generate relatively large force it could be connected to large arrow visible from distance or operate switches etc. If you find a device that would convert the mechanical analog signal (spring length) to digital signal you could send it by X10 or similar system via power line feeding the pump to the house.

dex3361 · Feb 16, 2010

Iplayfarmer said:
It sounds like the biggest challenge is getting something that can be monitored remotely. The easiest and cheapest methods (bubbler, chalk stick, and string with flag) don't lend themselves well to remote monitoring.

I guess worst case scenario you could put a remote camera looking at a gauge.

It can be done if you want to spend the money. Any 4-20 milliamp(from any pressure transmitter) signal can be the input to an RTU (remote Telemetry Unit) and can be sent fiber optic, Radio signal or hard wired. The question will then be do you want to spend the money to monitor the well depth. The cheapest Guage mount will be a bubbler type or a submersed pressure transmitter

Egon · Feb 16, 2010

There is a device called displacer. The beauty of it is relative simplicity and that the sensor is above ground and easily accessible. The displacer is an object (in example sealed 1/2" cooper or plastic pipe) hanging on a spring in the well. Because the volume of the displacer and specific gravity of water are also known it is easy to calculate the force extorted on the spring depending on how much water it displaced. The change in length of the spring is the measure of the water level change. Since the device can generate relatively large force it could be connected to large arrow visible from distance or operate switches etc. If you find a device that would convert the mechanical analog signal (spring length) to digital signal you could send it by X10 or similar system via power line feeding the pump to the house.

Why not use a strain gauge?

The Dougster · Feb 16, 2010

I'm still questioning the necessity of monitoring the static water level constantly... certainly it can be done but why? Unless your well is drilled into a karst aquifer, you will see very little change in the static level... <sigh>

hr3 · Feb 16, 2010

Might be a stupid question but why would you set a pump not even half way down the hole,,,another 150' would almost double the standby water.. and still have 50' of clearance from the bottom???

dcyrilc · Feb 16, 2010

hr3 said:
Might be a stupid question but why would you set a pump not even half way down the hole,,,another 150' would almost double the standby water.. and still have 50' of clearance from the bottom???

It was where the well contractor recommended putting it. I have never had a problem with it, but since it was drilled and the origional draw down test done, I have known several people whos wells have dried up during exceptionaly dry summers. Their water came back after we had some rain, but it got me to thinking... I have no way of knowing what my well has done during these periods other than that I have not run out of water. I could have easily been down to one or two feet of water above the pump and never known. Plus, since I don't live at the ranch and everything is automated, I figure it would not hurt to be able to remotely check the water level in the shaft during extremely dry conditions.

There are weather stations which allow remote monitoring and can graph hourly reading of rain fall for up to a year. My thought is that something similar for the well would be nice if a way can be found to do it.

I have thought about a low level alarm, but I realistically am only at the well house maybe 2 or 3 times a year and the well house is around 1000 feet from the main ranch where I spend my time. It could go off for two months without me ever knowing. Remote monitoring would allow me to check from home when I think about it and if I see a trend which could become questionable, I could do closer monitoring or even shut down the well for a period if need be before the 3HP pump ran dry.