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Thread: Shallow driven well ?'s

  1. #1
    DIY Junior Member bcd11's Avatar
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    Default Shallow driven well ?'s

    First off, THIS IS ONE GREAT FORUM!!! The pro's that answer questions are a godsend to us DIY'ers. Big time THANKS!

    Here's what I'm tangling with;
    -Live close to Lake Michigan, very FINE sand
    -Want a well to water lawn
    -Water at 14' below ground surface
    -Flotec 1 1/2 HP pump (not submersible/jet) w/1 1/2" intake and
    discharge

    Drove my first well w/36" point, 60 mesh gauze. The well flowed 15 gpm. I thought it should be more so called pump company. They said I'd better get more water to the pump or I'll burn out the bearings. Drove second well that produced 5 gpm and LOTS of air bubbles. Also drove the first well 2' deeper so there was 6' water in bottom of suction pipe. Now the wheels fall off the cart.

    Seems that FINE sand puts a death grip on a pipe. During the second driving of my good well I would put the wrench to the pipe just to make sure everything was tight. BIG MISTAKE! Because I could get the pipe to turn a little...eventually, doesn't mean the point assembly was turning. Flow went from 15 gpm to 0. Figured I'd pull the point clean it out and be OK. Yeah right, a week later I finally got the pipe out of the ground WITHOUT well point.

    I drove the second well another foot and now have much better flow along with the mandatory bubbles. I'll take the bubbles and leave the wrench in the tool bucket. So-o-o after that fool's story here are my questions.

    1-I can easily jet a 3" diameter PVC pipe down to the water level to use as a casing TO THEN lower a point or screen into and jet the point or screen down another 5-6'. It's a LOT easier than driving it and, in theory, should make it easier to pull the pipe AND point.. Is this a wise move? If it will work, should the suction pipe be PVC or could it be 1 1/4" black poly tubing?

    2-After reading some of the other posts in this forum I don't know if the gauze screen type of point is wise to use. Should I use a wound wire screen? If so, should it be a 7 or 10 slot and where is a good place to buy one?

    Again, thanks to all of you that KNOW WHAT YOU ARE DOING for taking the time and effort to help us that DON'T know what we are doing.

    Thanks in advance for any help you can offer.

    Bart

  2. #2
    Porky Cutter,MGWC Porky's Avatar
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    Default Driven Well!

    Your Flowtec is a lawn sprinkler pump, not a well pump! Meaning it pumps lots of water from a lake. These pumps are designed for flow but not pressure.

    You should have a Jet Pump for a well. Using a sand point I would have recommended using no more than a 1/2 jet pump (3/4 hp max.). You are getting air bubbles because you are sucking air somewhere (probably at the top of the well point at 14') or your pump is gravitating (it may sound like it has sand in it).

    If you want to continue using your existing pump (and no pressure) you will have to restrict the flow from the pump to a point where there are no bubbles in the return water, possibly drive several points at least 10 ft. apart and manifold them all together (keeping in mind you will get more flow but little pressure for sprinkler heads).

    Or install a 1/2 to 3/4 hp. jet pump to the existing well and check for flow (and air bubbles). Restrict the output flow to where you see little or no bubbles. OR drive more sand points some distance apart and manifold them together.

    NOTES: Do what works best for you. . .
    Washing the 3" PVC to the top of the water sand, then driving the point into the water bearing sand as far as possible works best in our area.
    [LIST]Don't overpump the point, to do so sometimes impacts the fine sand around the well point and restricts the flow.

    Porky, MGWC
    Master Ground Water Consultant

  3. #3
    In the Trades Bob NH's Avatar
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    Default

    To:
    Porky, MGWC
    Master Ground Water Consultant;

    Please enlighten us on the term "your pump is gravitating" from your post in this thread (QUOTED BELOW). It is a term with which I am not familiar and none of the definitions that I can find appear to apply to pumps.

    THE QUOTE FROM PORKY: "You should have a Jet Pump for a well. Using a sand point I would have recommended using no more than a 1/2 jet pump (3/4 hp max.). You are getting air bubbles because you are sucking air somewhere (probably at the top of the well point at 14') or your pump is gravitating (it may sound like it has sand in it)."

    NOTE: The QUOTE function doesn't seem to be working on your post.

  4. #4
    In the Trades Bob NH's Avatar
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    Default

    Quote Originally Posted by bcd11 View Post
    Here's what I'm tangling with;
    -Live close to Lake Michigan, very FINE sand
    -Want a well to water lawn
    -Water at 14' below ground surface
    -Flotec 1 1/2 HP pump (not submersible/jet) w/1 1/2" intake and
    discharge

    1-I can easily jet a 3" diameter PVC pipe down to the water level to use as a casing TO THEN lower a point or screen into and jet the point or screen down another 5-6'. It's a LOT easier than driving it and, in theory, should make it easier to pull the pipe AND point.. Is this a wise move? If it will work, should the suction pipe be PVC or could it be 1 1/4" black poly tubing?
    Bart
    I would jet a casing down, even 4" or 6" if possible. Then I would use a centrifugal pump (the one you have might work) without a screen to pump as much sand as possible out of the well. Make a pit (could be a plastic lined shallow area) to dump the water so the sand settles out and let the clarified (sand-free) water from the pit go back down the well. In settling the sand it is the area that counts, not the depth or volume.

    If you put the suction into the pit (above the sand) it will provide a lot of flow for jetting.

    If there is some variabity in size of the sand you could pump out a lot of the small sand and the coarser sand would form a larger filter.

    When you stop getting a lot of sand you can put the screen down and water the lawn.

    If you still get too much sand for the sprinkler heads you can settle most of it out by running it through a horizontal pipe or tank.

  5. #5
    DIY Junior Member bcd11's Avatar
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    Long Beach, IN-Near Lake Michigan shoreline
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    Default Big Time "THANK YOU" to Porky and Bob NH!

    I really appreciate the help and information.

    Porky, Thanks for the suggestion of driving the points deeper. They are now at 22'-24' with 7'-8' of water standing in the bottom of the suction pipes. I did a seat of the pants flow test and am getting 27 +/- gpm with a static pressure of 40 psi. I haven't run a residual pressure test yet. Your suggestion of not overpumping got me going on the second point REAL FAST! I am now mustering the energy to jet/drive a third point, (wife thinks I'm crazy).

    Bob NH I have three questions regarding your suggestion of a 4" or 6" casing. Would you jet/drive the casing down to the water level (14') or down to the depth of my current points (22' - 24')? If to the 22' -24' depth should there be enough water entering the solid wall casing (no holes, mesh, gauze, or slots) for the pump to continuously draw (the water level in the casing should be 7'-8')? If taking the casing to 22'-24' depth should I use a screen over the end of the suction pipe instead of a sand point?

    Again, thank you both for taking the time an effort to help me.

    Bart

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