Who's good at math?

[Chris142]

I have a question I do not know how to figure out.

When our well got too low to pump water the water level was @286ft below the surface.

When it began to rise I had the pump put back in the casing. It was @282ft below the surface. At this time it took 3minutes 40 seconds to get to the surface once I turned the pump on .

Now that the pump is in the well I can't measure the water level.

The water level has continued to rise.

Now it's taking 2 minutes 22 seconds to reach the surface.

Is there a way to guestimate the currant water level with those times? The drop pipe will retain the currant water level and that's that much less pipe it has to fill before it gets to the surface.

Pump is advertised as a 5 gpm if that matters.

 

[SC Maintenance]

Its difficult becauase as the water gets closer and closer to the top, the static head on the pump gets higher, and therefore the water rise slows down. So it starts fast and slows as it gets towards the top.

So now it has less distance to travel so overall trip is faster, but the distance it has to travel is the slowest part of the trip. By how much depends on the pump. Might be almost nothing. Might be a lot?

I think

If it were linear, 3:40 = 220s, and 2:22 = =142s, so depth from the top when its linear would be 282ft x (142/220) = 182 feet from top. My guess is its little closer to the top than 182 feet, but hard to say by how much.

Would that number make any sense?

 

[mclasser]

We can use dimensional analysis:

3 min 40 sec = 3.67 min appx.

2 min 22 sec = 2.37 min appx.

2.37 min x 282 ft/3.67 min

= 182.1 ft

EDIT: @SC Maintenance beat me to it!

 

[Nukeman7]

Chris, if you assume everything is linear, it would appear the level is now approximately 182 feet below the surface. However, as SCM stated, the static water pressure increases as the column rises; therefore , it is probably less than 182 feet.

 

[Chris142]

Thanks guys. That's wild if it's that high right now. The original level was 257 in 1965

 

[Nukeman7]

If I recall correctly, you were potentially looking at a ~$50K bill at the end of last year to re-drill the well. Thank goodness that things have taken a turn for the better. Maybe good things do come to those who wait!

 

[Chris142]

If I recall correctly, you were potentially looking at a ~$50K bill at the end of last year to re-drill the well. Thank goodness that things have taken a turn for the better. Maybe good things do come to those who wait!

It's going to happen again and the casing may completely colapse at any time. Hopefully this will buy me more time.

The Mojave river that fills the aquifer is still flowing. Very unusual as it's rarely flowing and never in June or july

 

[JHZR2]

Thanks guys. That's wild if it's that high right now. The original level was 257 in 1965

As said, it’s not linear. So it’s probably more like reverting to the norm, which if you assume is the 1965 level (bad assumption) may be more like it.

I think your best bet would be to measure gpm, and you knew your pump power rating, then you could estimate from a chart like this:

 

[mk378]

The pipe is supposed to stay full because there is a check valve at the pump that should not let any water flow back down. If that is working, the water at the top of the pipe should start to flow almost instantly (subject to the speed of sound) when the pump is turned on every time, except the first time or if there isn't any water at the pump.

 

[Chris142]

As said, it’s not linear. So it’s probably more like reverting to the norm, which if you assume is the 1965 level (bad assumption) may be more like it.

I think your best bet would be to measure gpm, and you knew your pump power rating, then you could estimate from a chart like this:

View attachment 163844

Pump is 1hp

 

[Chris142]

The pipe is supposed to stay full because there is a check valve at the pump. If that is working, the water at the top of the pipe should start to flow almost instantly (subject to the speed of sound) when the pump is turned on every time except the first time.

There's nothing there now. We pulled it all out and did not replace any of them due to finances. I put one at ground level to keep the water from running out of my tank and back down the well.

 

[walterjay]

Glad to see your well recovering. I knew it would.

 

[JHZR2]

There's nothing there now. We pulled it all out and did not replace any of them due to finances. I put one at ground level to keep the water from running out of my tank and back down the well.

Brand/model is somewhat important.

But you can look at something like this if hil know your gpm. The losses in your piping which does affect the flow rate, are the same regardless.

 

[Chris142]

Glad to see your well recovering. I knew it would.

The well was 299 ft originally. The casing collapsed @288ft so I can't put the pump lower than that.

But ya it's working now.

 

[mk378]

With the check valve at the top, most of the water will drain out of the pipe but it would stop to stand about 30 feet above the level in the well, due to atmospheric pressure. The rest of the pipe would be in vacuum. So on the second start there was a 30 foot head start vs the first one that was completely empty, plus however much the water rose in the well.

 

[Chris142]

Brand/model is somewhat important.

But you can look at something like this if hil know your gpm. The losses in your piping which does affect the flow rate, are the same regardless.

View attachment 163851

It's a Franklin motor running a grundfas pump.

 

[Chris142]

With the check valve at the top, the water would drain out of the pipe but stop running down and stand about 30 feet above the level in the well, due to atmospheric pressure. The rest of the pipe would be in vacuum. So on the second start you had a 30 foot head start vs the first one that was completely empty, plus however much the water rose in the well.

It won't go all the way down and seek its level? I timed it several times when it was taking 3:40 minutes

 

[mk378]

Not unless air can get into the pipe. Which it will eventually because nature abhors a vacuum...

 

[JHZR2]

It's a Franklin motor running a grundfas pump.

That really doesn’t tell you much. As you can see there are pump curves and they’re dependent upon many factors. You should have the curves for your system.

 

[Chris142]

Update: the Mojave river is still flowing. Not as much as before but should be enough to keep the aquifer up. Here is a pic from my yard

Currantly it's taking 1:40 min to get from the static level to the top of the well.