Bore-Hole Water Quantity Varies During The Day

[offset]

I am having problems with the water varing between 40 ltr per min to 80 ltrs per min and I cannot understand why, I can understand that i would have a problem if I was drawing too much water but I would thought that would give me a problem of the water stopping but at 40 ltrs the water will keep coming for hour any ideas

[WatersEdge]

Best guess while knowing nothing certain.

You may have debris clogging your intake in the well.

Suction will pull debris and hold it there,

then when the pump shuts off the debris is free to fall or float away.

It is unpredictable exactly how and when the debris comes to the intake

so each episode would logically be a bit different.

[offset]

Best guess while knowing nothing certain.

You may have debris clogging your intake in the well.

Suction will pull debris and hold it there,

then when the pump shuts off the debris is free to fall or float away.

It is unpredictable exactly how and when the debris comes to the intake

so each episode would logically be a bit different.

That is possible but the flow of water can go up from 40 to 80ltre per min as well as down and I would of have thought that any debris would stay while the pump is turned on

[ksamuiguy]

Best guess while knowing nothing certain.

You may have debris clogging your intake in the well.

Suction will pull debris and hold it there,

then when the pump shuts off the debris is free to fall or float away.

It is unpredictable exactly how and when the debris comes to the intake

so each episode would logically be a bit different.

That is possible but the flow of water can go up from 40 to 80ltre per min as well as down and I would of have thought that any debris would stay while the pump is turned on

When the well was drilled the well company told some one what the capacity of the well was/is. If you exceed this amount you take a chance of collapsing the well walls or having to wait for the well to refill.

If you get water good flow and it is steady at 40 Lm you need to adjust the valve at the well head so you only pump 40 liters a minute. As wells get older they pump less water there is also the problem of many well added in the area lowering the water table.

Best to find a flow and set the flow with the valve and leave it.

Good Luck

Edited February 17, 2011 by ksamuiguy

[Foreverford]

Best guess while knowing nothing certain.

You may have debris clogging your intake in the well.

Suction will pull debris and hold it there,

then when the pump shuts off the debris is free to fall or float away.

It is unpredictable exactly how and when the debris comes to the intake

so each episode would logically be a bit different.

That is possible but the flow of water can go up from 40 to 80ltre per min as well as down and I would of have thought that any debris would stay while the pump is turned on

When the well was drilled the well company told some one what the capacity of the well was/is. If you exceed this amount you take a chance of collapsing the well walls or having to wait for the well to refill.

If you get water good flow and it is steady at 40 Lm you need to adjust the valve at the well head so you only pump 40 liters a minute. As wells get older they pump less water there is also the problem of many well added in the area lowering the water table.

Best to find a flow and set the flow with the valve and leave it.

Good Luck

I'm just starting to use a new well and there really isn't an understanding of how to test well capabilities here in Thailand at least locally. Other wells I've drilled in California we did what you call a pump down test and you put in a highflow pump and log your flows for a certain amount of time and then see how much "drop down" (the difference of the original height of water and where it is after a certain amount of time and flow has occurred) you get. Then every hour you record what the water height is until it reaches it normal level. Another test can be to try to pump at a certain amount over a long period of time to see if you have no "drop down" and then you can put a calibrated restrictor on your line and pump 24/7 if you choose.

This is what I am going to attempt to do. they don't seem to have the restrictors readily and locally available (word of mouth from my very very good well man) and since I am returning to the US shortly I am going to buy an assorted varied amount of them and then create an manifold with valves on it and just pump through each one and see at which flow I can pump continuously and go with that. it is a great time now for testing wells as the rainy season is long past and hopefully you can get a "worst case" reading that will work for you.

This is definitely a bit off subject but partially relevant and also do you have a multi-stage submersible pump or is yours an above ground FF

[ksamuiguy]

Best guess while knowing nothing certain.

You may have debris clogging your intake in the well.

Suction will pull debris and hold it there,

then when the pump shuts off the debris is free to fall or float away.

It is unpredictable exactly how and when the debris comes to the intake

so each episode would logically be a bit different.

That is possible but the flow of water can go up from 40 to 80ltre per min as well as down and I would of have thought that any debris would stay while the pump is turned on

When the well was drilled the well company told some one what the capacity of the well was/is. If you exceed this amount you take a chance of collapsing the well walls or having to wait for the well to refill.

If you get water good flow and it is steady at 40 Lm you need to adjust the valve at the well head so you only pump 40 liters a minute. As wells get older they pump less water there is also the problem of many well added in the area lowering the water table.

Best to find a flow and set the flow with the valve and leave it.

Good Luck

I'm just starting to use a new well and there really isn't an understanding of how to test well capabilities here in Thailand at least locally. Other wells I've drilled in California we did what you call a pump down test and you put in a highflow pump and log your flows for a certain amount of time and then see how much "drop down" (the difference of the original height of water and where it is after a certain amount of time and flow has occurred) you get. Then every hour you record what the water height is until it reaches it normal level. Another test can be to try to pump at a certain amount over a long period of time to see if you have no "drop down" and then you can put a calibrated restrictor on your line and pump 24/7 if you choose.

This is what I am going to attempt to do. they don't seem to have the restrictors readily and locally available (word of mouth from my very very good well man) and since I am returning to the US shortly I am going to buy an assorted varied amount of them and then create an manifold with valves on it and just pump through each one and see at which flow I can pump continuously and go with that. it is a great time now for testing wells as the rainy season is long past and hopefully you can get a "worst case" reading that will work for you.

This is definitely a bit off subject but partially relevant and also do you have a multi-stage submersible pump or is yours an above ground FF

Inany well here deeper than 30 meters they are multi-stage well pumps, either Franklin, Grundfos. Since we don't have flow restrictors we use a valve and weld it at the setting we want. Effective until "they" open/change the "bad valve" because it is restricting the water. The well is usually bad in a short while after that.

Again Good Luck

[offset]

ksamuiguy

This is a new bore-hole when it was finished I did not see the guy do any testing of the rate of flow he just said that is the best I could expect to get, when the flow went down again he then told me that he had closed down a valve to keep a steady constant flow but I could not understand that if he had restricted it to 40 lpm why does it increase to 80 lpm sometimes I also would of thought that if at 80 lpm I was starving the hole of water I should see the water splutter and air coming through the pipe is there any reason why the flow should change during the day

Foreverford

It is a submersible pump you and are correct about the testing I have not seen a valve on my bore head the guy said that he adjusted the valve on the pump but I did not know that they had any valves on the pump because you would have to keep lifting it up 70 mtrs to adjust it but I know nothing about pumps so I may be wrong

[ksamuiguy]

ksamuiguy

This is a new bore-hole when it was finished I did not see the guy do any testing of the rate of flow he just said that is the best I could expect to get, when the flow went down again he then told me that he had closed down a valve to keep a steady constant flow but I could not understand that if he had restricted it to 40 lpm why does it increase to 80 lpm sometimes I also would of thought that if at 80 lpm I was starving the hole of water I should see the water splutter and air coming through the pipe is there any reason why the flow should change during the day

Foreverford

It is a submersible pump you and are correct about the testing I have not seen a valve on my bore head the guy said that he adjusted the valve on the pump but I did not know that they had any valves on the pump because you would have to keep lifting it up 70 mtrs to adjust it but I know nothing about pumps so I may be wrong

If you know the make and model of the pump you can "Google" it and get the pump curve, it will tell you how much water can be pumped at a certain depth.

My experience here is they tell you the capacity of the well, but install a pump that will pump many times the well capacity. I guess it is up to you to set the flow where the water comes out of the well.Again easy with a valve and a bucket. Better to have water all the time than a lot for a short time, also not good for the pump.

If you are getting dirt out of the well you are over pumping the well, and this may be in indication of the sides of the bore hole collapsing. Again some water all the time is better than no water at all.

[Khonwan]

Hi Offset

Check your voltage at your control panel during peak flow and reduced flow times. If you are on a shared community transformer, you may be experiencing fluctuations in your power supply. Any reduction of voltage would decrease the power of the pump motor and hence water flow. Your description would certainly fit voltage fluctuation.

I too am having a problem with my bore…an insurmountable one (other than using multiple bores). I’ve now had 3 bores drilled at different locations on my farm (depths of 45m, 90m and 72m – all granite). The best of these was the 90m bore, which my driller swore would produce 5 m³ per hour and had me fit a 2hp Franklin. It didn’t. It subsequently proved to produce 0.75 m³ per hour – 12.5 litres per minute. The pump produces 200 litres per minute at the bore head for the first couple of minutes until the initial column of water is used, then only 12.5 litres per minute reflecting the bore recharge rate. This rate does not meet my needs since I need 25 m³ per day to keep my pond topped up. Should I decide to make use of the meager flow I have, and run it 24/7, I’ll have to buy another motor with the lowest rating (¼ – ½ hp ?) available. Using my 2hp motor for this flow would result in a complete waste of electricity and probably a much shortened motor-life.

Rgds

Khonwan

[Foreverford]

Hi Offset

Check your voltage at your control panel during peak flow and reduced flow times. If you are on a shared community transformer, you may be experiencing fluctuations in your power supply. Any reduction of voltage would decrease the power of the pump motor and hence water flow. Your description would certainly fit voltage fluctuation.

I too am having a problem with my bore…an insurmountable one (other than using multiple bores). I've now had 3 bores drilled at different locations on my farm (depths of 45m, 90m and 72m – all granite). The best of these was the 90m bore, which my driller swore would produce 5 m³ per hour and had me fit a 2hp Franklin. It didn't. It subsequently proved to produce 0.75 m³ per hour – 12.5 litres per minute. The pump produces 200 litres per minute at the bore head for the first couple of minutes until the initial column of water is used, then only 12.5 litres per minute reflecting the bore recharge rate. This rate does not meet my needs since I need 25 m³ per day to keep my pond topped up. Should I decide to make use of the meager flow I have, and run it 24/7, I'll have to buy another motor with the lowest rating (¼ – ½ hp ?) available. Using my 2hp motor for this flow would result in a complete waste of electricity and probably a much shortened motor-life.

Rgds

Khonwan

Hey Khonwan (sweet dude?) probably a darn good call on the voltage. Hurts to hear what happened to you with all your tries. It seems that tiny pumps in all three wells might at least give you some kind of return for all you have invested in the wells but still isn't going to fulfill your needs. I dug a klong almost completely around the 14 rai rectangular small farm and without it my leaky big lake would be an utter catastrophe. Hopefully bentonite might slolve the lake problem. I put in a Mercury 1 hp submersible in the farm well and a tank tower is going up next week and ultimately the desire is to use it to keep the lake and klongs full for irrigation and aquaculture so I will definitely be looking for the ability to run it 24/7 when I do pump. Pump down tests will be essential to really dial it in and to determine what size pump would be optimum. the bigger farm out nearer the border has lots of water under it, I believe, so i wasn't worried about buying a pump that might be a bit too big right now (hopefully it is too small) but so far i have pumped it for hours and the flow has remained very constant with beautiful sweet water but who knows what the head level is doing. I went around in circles trying to find someone who could do a simple water well test for a domestic well last year and got nowhere. the best i got was finally back to Bangkok and they said i had to specify exactly what i wanted them to test for (Flourine etc and a million other things at about 500 baht a pop for each, just ridiculous). I need some bentonite blocks to mash against my head to make it all make sense it appears. How can it be so difficult to get a domestic well water test? really? What am I missing here? Hopefully the next earthquake we get will shimmy the Jimmy and make a bunch of water just want to bust out of your wells. I'll tell you it was mighty pleasing when they hit water when they were drilling and it just started blowing out of the hole. choke dee sweet dude FF

[offset]

Khonwan

At first I thought it might be a voltage problem but the control unit tells me it does not matter if the voltage is 200 or 230 rate of water varies without any change of voltage

Foreverford

I have a spare bore-hole which I am told has a water supply can I put a pump in that and connect it up to the same water lines as the other pump to give me more water flow or would I have to have separate pipes lines

for each pump

[Boksida]

I think Khonwan could still be close to the problem regarding electricity supply, but the problem may be with frequency fluctuation. This is much harder to detect but can cause changes in pump speed. I would suggest to anybody putting a new pump that they look for a 3 phase one. Several manufacturers are now offering variable frequency drives which can convert single phase power to three, and the 3 phase pump can then operate at different speeds. This is usually set up to maintain a constant pressure. The fellow that told you that he adjusted a valve on your pump is probably bullshitting as usually the only valve at the pump will be a non return valve.

For Foreverford, I would think your opinion on your very, very good well man may need some rethinking. There are many companies in Thailand capable of performing pumping tests. It is a contractual requirement for most government and industrial supply drilling projects. Interestingly, one of the international leaders in this field is a Thai company. The economic reality is that none of these companies is probably going to be interested in testing a single domestic well in the sticks. You could do your own pumping test if you can maintain a constant flow rate on your pump. You will need to measure water levels at increasingly longer intervals throughout the test. A simple water level dipper can be made with twin flex electrical cable weighted with something like fishing line sinkers. The downhole ends have to be exposed but incapable of touching. When both wires are submerged, the electrical resistance will change and you can measure that with a simple ohmmeter. Practice in a bucket at the surface to see which scale gives you the best readings. Easiest way is to mark the cable at the static water level and measure the change from there with a tape. There also other ways involving tyre pumps, a gauge and plastic tubing but not as accurate. Interpretation of the test is done these days by anybody with the correct software but there is nothing wrong with plotting the results on semilog graph paper and doing it manually. Your nearest university may be able to help.

Telling you that inline restrictors here are not available is just pulling your pants down. Every reasonable size town in Thailand has a machine shop capable of making something like this. Brass might be the best as it is cheap, easy to machine and resistant to corrosion. You can also buy Teflon in various size cylinders which would also do the job.

Physical and chemical testing is mostly done in Bangkok, although most provincial universities with a geology/hydrogeology department will also do them. If you need the results on a regular basis, you might want to consider buying one of the simple handheld devices which will measure conductivity, TDS and pH.

[rafish]

Best guess while knowing nothing certain.

You may have debris clogging your intake in the well.

Suction will pull debris and hold it there,

then when the pump shuts off the debris is free to fall or float away.

It is unpredictable exactly how and when the debris comes to the intake

so each episode would logically be a bit different.

That is possible but the flow of water can go up from 40 to 80ltre per min as well as down and I would of have thought that any debris would stay while the pump is turned on

When the well was drilled the well company told some one what the capacity of the well was/is. If you exceed this amount you take a chance of collapsing the well walls or having to wait for the well to refill.

If you get water good flow and it is steady at 40 Lm you need to adjust the valve at the well head so you only pump 40 liters a minute. As wells get older they pump less water there is also the problem of many well added in the area lowering the water table.

Best to find a flow and set the flow with the valve and leave it.

Good Luck

I'm just starting to use a new well and there really isn't an understanding of how to test well capabilities here in Thailand at least locally. Other wells I've drilled in California we did what you call a pump down test and you put in a highflow pump and log your flows for a certain amount of time and then see how much "drop down" (the difference of the original height of water and where it is after a certain amount of time and flow has occurred) you get. Then every hour you record what the water height is until it reaches it normal level. Another test can be to try to pump at a certain amount over a long period of time to see if you have no "drop down" and then you can put a calibrated restrictor on your line and pump 24/7 if you choose.

This is what I am going to attempt to do. they don't seem to have the restrictors readily and locally available (word of mouth from my very very good well man) and since I am returning to the US shortly I am going to buy an assorted varied amount of them and then create an manifold with valves on it and just pump through each one and see at which flow I can pump continuously and go with that. it is a great time now for testing wells as the rainy season is long past and hopefully you can get a "worst case" reading that will work for you.

This is definitely a bit off subject but partially relevant and also do you have a multi-stage submersible pump or is yours an above ground FF

Not knowing your location, or density of neighboring population, I would think as suggested by previous poster that the water table is variable and there for reacts as the tides rise and fall or the over-consumption by neighbors draws on the table. In Thailand its not like your taping into any underground streams. Using a "restrictor," will certainly reduce the flow however it won't increase the wells productivity. It appears that the flow is irregular not due to your pump or other possible variance. How deep is your well? Well depth in the LOS is usually very shallow interms of western standards. Well water is by no means to be considered potable and often contains many caustic additives by farmers, neighbors toilets, and industry. I do not recommend you use this water for cooking, drinking or even bathing unless treated first.

Good luck

[Khonwan]

Hi Boksida

Sorry for the delay – I’m having problems connecting to the Internet (awaiting a new AIS cellsite). My 2hp Franklin is 3 phase so I was very interested in your comments re. use of a VFD to reduce the motor speed; I hadn’t thought about that. I’m now looking for a supplier of an appropriate VFD – can you point me in the right direction and give me an idea of likely cost?

Rgds

Khonwan

[offset]

Not knowing your location, or density of neighboring population, I would think as suggested by previous poster that the water table is variable and there for reacts as the tides rise and fall or the over-consumption by neighbors draws on the table. In Thailand its not like your taping into any underground streams. Using a "restrictor," will certainly reduce the flow however it won't increase the wells productivity. It appears that the flow is irregular not due to your pump or other possible variance. How deep is your well? Well depth in the LOS is usually very shallow interms of western standards. Well water is by no means to be considered potable and often contains many caustic additives by farmers, neighbors toilets, and industry. I do not recommend you use this water for cooking, drinking or even bathing unless treated first.

Good luck

I was told that it had been drilled to a depth off 92 meters and at a guess the pump is 70 meters down I was left with 12 meters of extra pipe to go down further if I needed to but I am not sure that would help me it may extend the time of good water flow by a little but I would still have the same problem

Does anybody know if I could run 2 pumps on the same watering system

[Khonwan]

Does anybody know if I could run 2 pumps on the same watering system

Yes, you can run 2 bores/pumps into the same water line. Probably better to install additional check valves at the Y junction.

[offset]

Does anybody know if I could run 2 pumps on the same watering system

Yes, you can run 2 bores/pumps into the same water line. Probably better to install additional check valves at the Y junction.

Thanks for your reply I think that is the way I will go

[Foreverford]

Does anybody know if I could run 2 pumps on the same watering system

Yes, you can run 2 bores/pumps into the same water line. Probably better to install additional check valves at the Y junction.

Thanks for your reply I think that is the way I will go

sorry i couyldn't reply sooner but running a bit hard now. I'm putting in a tank tower and will pump to it from the well and then run all my lines off the tank not the pump (or pumps in your situation with more than one well). You can have a booster pump or a "pressure tank system" to use from your stoerage tank if you need high pressure or high flow.

[Foreverford]

I think Khonwan could still be close to the problem regarding electricity supply, but the problem may be with frequency fluctuation. This is much harder to detect but can cause changes in pump speed. I would suggest to anybody putting a new pump that they look for a 3 phase one. Several manufacturers are now offering variable frequency drives which can convert single phase power to three, and the 3 phase pump can then operate at different speeds. This is usually set up to maintain a constant pressure. The fellow that told you that he adjusted a valve on your pump is probably bullshitting as usually the only valve at the pump will be a non return valve.

For Foreverford, I would think your opinion on your very, very good well man may need some rethinking. There are many companies in Thailand capable of performing pumping tests. It is a contractual requirement for most government and industrial supply drilling projects. Interestingly, one of the international leaders in this field is a Thai company. The economic reality is that none of these companies is probably going to be interested in testing a single domestic well in the sticks. You could do your own pumping test if you can maintain a constant flow rate on your pump. You will need to measure water levels at increasingly longer intervals throughout the test. A simple water level dipper can be made with twin flex electrical cable weighted with something like fishing line sinkers. The downhole ends have to be exposed but incapable of touching. When both wires are submerged, the electrical resistance will change and you can measure that with a simple ohmmeter. Practice in a bucket at the surface to see which scale gives you the best readings. Easiest way is to mark the cable at the static water level and measure the change from there with a tape. There also other ways involving tyre pumps, a gauge and plastic tubing but not as accurate. Interpretation of the test is done these days by anybody with the correct software but there is nothing wrong with plotting the results on semilog graph paper and doing it manually. Your nearest university may be able to help.

Telling you that inline restrictors here are not available is just pulling your pants down. Every reasonable size town in Thailand has a machine shop capable of making something like this. Brass might be the best as it is cheap, easy to machine and resistant to corrosion. You can also buy Teflon in various size cylinders which would also do the job.

Physical and chemical testing is mostly done in Bangkok, although most provincial universities with a geology/hydrogeology department will also do them. If you need the results on a regular basis, you might want to consider buying one of the simple handheld devices which will measure conductivity, TDS and pH.

Hey Bok buddy thanks for the response. I can do all the pump tests no problem but i want a good inexpensive water quality test and can't find them available yet to satisfy me. I ain't as simple as in California that's for sure. I'll invest a few bucks to purchase restictors that I can dial in immediately as I just don't have the time at this point to fiddle with making my own and they may come in useful in the future if tyhe circumstances changes. I can tell you my well guy is a wizard and dowses and quarantees water and does it for peanuts. He walked away fro a bunch of days of work on one of our domestic wells and decided to drill in another area and bingo beautiful clean and sweet tasting high flow water that is allowing us to use probley 50 times more water than we were able to use from the old and now abandoned well. Couldn't wish to find a better fellow and I guesws everybody feels the same as he is never wityhout work and has manaGED TO USE THE SAME RIG FOR NEARLY 20 YEARS WITH HE SAID ONLY ONE ACTUAL BREAKDOWn. good luck to all got ta get. it's a Ford for me

[Boksida]

Hi Boksida

Sorry for the delay – I'm having problems connecting to the Internet (awaiting a new AIS cellsite). My 2hp Franklin is 3 phase so I was very interested in your comments re. use of a VFD to reduce the motor speed; I hadn't thought about that. I'm now looking for a supplier of an appropriate VFD – can you point me in the right direction and give me an idea of likely cost?

Rgds

Khonwan

I am on the move at the moment and can not check but I believe Franklin have a system called SubDrive. The Bangkok agent I have dealt with has the email address chanyporn at anet dot net dot th (Ms Chany). Grundfos also have something I think is called Redi-Flo. The Grundfos guy I generally direct enquiries to is Khun Roongsak (rleamwanich at grundfos dot com). He is a bit on the lazy side and after I get the information from him I can generally buy a pump cheaper through one of their upcountry agents. All the VFDs I have bought in Thailand for use with submersible pumps have been from ABB in Bangkok. These are much larger than what you require so unfortunately I can not be too much help on prices. The fellow I have found most helpful there is Khun Sirichote (sirichote.singsa at th dot abb dot com)

[Khonwan]

Hi ForeverFord

I forgot to reply, I’m unfortunately neither sweet by nature nor by mouth. KHONWAN is to naKHON saWAN as KORAT is NaKOn RATchasima.

I think I could do with your driller chap paying me a visit but I guess he’s a long way from me (can’t recall where you’re located).

Rgds

Ford-owning Sweet Dude

Boksida: thanks for the info – I’ll check it out. Based on my Internet trawling, I reckon it should cost around US$125.

[offset]

Does anybody know if I could run 2 pumps on the same watering system

Yes, you can run 2 bores/pumps into the same water line. Probably better to install additional check valves at the Y junction.

Thanks for your reply I think that is the way I will go

sorry i couyldn't reply sooner but running a bit hard now. I'm putting in a tank tower and will pump to it from the well and then run all my lines off the tank not the pump (or pumps in your situation with more than one well). You can have a booster pump or a "pressure tank system" to use from your stoerage tank if you need high pressure or high flow.

That is what I intended to do (not a tower tank) but I need about 120 ltrs per min and only having 40 ltrs per min from the bore hole nearest to where I was going to put the tank meant that the sums did not match up so with the 2 pumps I intend to run them for a while to see what the constant flow is and if it is about 80 ltrs per min I will then put a tank system in to allow me to run a sprinkler system

I have a tank tower on the land adjoining my house which is OK but I feel that it was a expense that was not justified where a tank lower at ground level with a pump on will give me enough pressure to do what I want

[Foreverford]

Hi ForeverFord

I forgot to reply, I'm unfortunately neither sweet by nature nor by mouth. KHONWAN is to naKHON saWAN as KORAT is NaKOn RATchasima.

I think I could do with your driller chap paying me a visit but I guess he's a long way from me (can't recall where you're located).

Rgds

Ford-owning Sweet Dude

Boksida: thanks for the info – I'll check it out. Based on my Internet trawling, I reckon it should cost around US$125.

We're in Buriam aat the Surin Cambodia border. He is Actually drilling very nearby and said that the govt next year is going to require permits to put in wells (in our area at least but didn't ask details). I know he has journeyed at 500k to work but he is basically fully booked for life so I think he is just paying back old favors when he3 travels. I told the wife tyo ask him when he could put our last well in before permit time at the big farma and he saidf anytime we wanted (he seems to like us and we are rather close to his village so have many mutual friends) he would just have to tell a lie to whoever waas n ext in line. we originally booked him about 4 months in advance but were sdtill flezxible. Choke dee and a Ford on an open highway with the sun going down Forever