Well Recovery

Discussion in 'Pumps and Tanks Well Forum & Blog' started by tvl, Aug 13, 2008.

  1. tvl

    tvl Member

    Messages:
    139
    Location:
    South Carolina
    After much research and invaluable information from this site, I have come to a conclusion regarding my water well. With the drought situation here in SC for the past 3 years, the underground stream which feeds our well is getting depleted.

    As a refresher for the readers, our well was dug in 1978. It is a 145 feet deep sand well and has always had a static water level of approximately 111 feet (and that still applies today). The 1 HP pump hangs about 132 feet down into the well. From 1978 up until this year, I could always pump 12 gpm with no problem. As a matter of fact, in 1978, the well driller stated we had a capcity of 30+ gpm (I've never pumped more than 12 gpm with our irrigation system). Currently, our well will provide only approximately 10 gpm.

    My question is: After a severe drought, which may last for several years, can OR will an underground stream recover to its original state after sufficient rain has come? If this is possible, I'm sure it may take up to 3 years to reverse the situation.

    Although I'm not sure of the answer, I'm sure there are experts here that can refer to their past experience and comment. I guess what I am asking is will this water well slowly continue to "die" or is there hope. If it's going to slowly get worse, then I may as well dig another.

    Thanks so much!
  2. valveman

    valveman Moderator Staff Member

    Messages:
    4,586
    Location:
    Lubbock, Texas
    If your supply of water is being depleted, usually the static water level will drop. If your well has always been, and is still at 111' to water, it may not be the supply that is the problem but, rather the perf or screen to the well. All areas are different, so a local well man may be able to tell you if the supply is depleting, or if the well screen or perf just needs cleaning.
  3. tvl

    tvl Member

    Messages:
    139
    Location:
    South Carolina
  4. valveman

    valveman Moderator Staff Member

    Messages:
    4,586
    Location:
    Lubbock, Texas
    If the water level outside the casing stays at 111' while the water level inside the casing drops, the screen is restricting the flow. If the water level outside the casing drops the same as inside the casing, the supply is reduced.

    It is impossible to tell what the water level outside the casing is, unless you have another well close by to monitor. If you turn the pump on and pull the water level in the well down, then you should be able to see water seeping into the casing at 110' or so, if the screen is the problem. If it is a supply problem, there won't be any water seeping into the casing above the water in the well. You may need to drop a camera in the well to see these things but, cameras are more common and less expensive than they use to be.

    If the screen is clogged, there are chemical treatments, air jetting, fracing, and other ways of cleaning the screen. If it is steel casing, an acid treatment may open it up. It all depends on what is doing the clogging.

    A local well man may just know what you need off the top of his head. Experience is priceless in situations like these.
  5. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    You said the well was a sand well which tells me there is a screen of some sort. The well was drilled in 1978, that's a long time for any screen to stay clean. Unless you have pristine water with no minerals, you should assume your screen is getting plugged.

    bob...
  6. tvl

    tvl Member

    Messages:
    139
    Location:
    South Carolina
    I will call on a local expert, but would like to know beforehand how something like this is accomplished. The bottom portion of the well casing itself is the screen. There are very tiny slots in the PVC pipe which allow water to filter through ........... of course, the PVC pipe came this way as these were not cut with a saw or anything. I can see how these slots would get plugged over time.

    So, once again, how would a problem like this be corrected? What is the process? Is it a very expensive or time consuming procedure?

    Thanks!
  7. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    I have never been a fan of PVC screens, but I assume Hydrofracting would work and so would Nu-Well Tablets to an extent. Your local guys can give you a lot better advice than we can.

    bob...
  8. tvl

    tvl Member

    Messages:
    139
    Location:
    South Carolina
    Ah! Nu-Well tablets have been mentioned in the past and I forgot this!

    In an effort to get ahead and possibly save a service call, can the homeowner use the Nu-Well tablets themselves?. If this method has a very good chance of doing the job without damaging the PVC pipe, I am all ears. I am assumming you simply remove the pump and drop pipe and drop the tablets or cleaning solution in the well ............ correct???

    If this is a correct assumption, how much of this prodcut will I need and are there any special precautions?

    Thanks again!
  9. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    It's not that simple. I don't know what kind or size of screen you have. If it were a simple 4' SS Screen like I'm familiar with I would say go for it, but if you have 20 or 40 foot of perfed PVC, they may not do much good.

    Again, this is where the local guy comes in.

    bob...
  10. tvl

    tvl Member

    Messages:
    139
    Location:
    South Carolina
    UPDATE:

    I contacted a local well man and got some information. He suggested I first try something myself. He stated I should purchase 1 gallon of Clorox and pour it into the well and let it stand for at least 24 hours. He stated this will HELP open up any clogs on the screen which might be from bacteria, etc. If this didn't help, then try about 1/4 cup of chlorine and let it stand for at least 24 hours also.

    If neither method helped, he stated he could come by and drop a camera down in the well and determine if it's really a plugage issue as I am thinking. If it is truly plugged there is another individual not too far away that can drop brushes in the well and hrdro-clean the casing.
  11. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    Clorox might kill bacteria but it is not going to help any in cleaning mineral from the screen.

    Most clogs on screens no matter what kind they are stick to the outside of the screen and on the sand that is wedged into the slots. I have no idea how a brush could do a bit of good. But they are the experts in your area.

    bob...
  12. valveman

    valveman Moderator Staff Member

    Messages:
    4,586
    Location:
    Lubbock, Texas
    Those brushes by Cotey Chemical are pretty cool. They have a surge block down the center of them that helps the brushes get where they need to be. Used with the right chemical, I have seen these brushes do amazing things. Let us know how it works out.
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