Hand Dug Well....not A Borehole

[jaideeguy]

I live in a rice farming community in Chiang Mai and am considering a simple old fashioned hand dug well lined with 1 mtr cement rings. We have surface water at around 3 mtrs now in middle of the dry season as I have observed in other wells. There are few houses near by to polute and nearest septic tank [mine] is 35 mtrs away. Clay soil, so I think most polutants would be well filtered by soil.

questions.....

1] should I worry about polution?? we won't be drinking the water, but will use it for household washing and watering the yard.

2] how much lower than water table should I dig it??

3] and how much recovery time should I expect if I pump it dry??

vague questions, I know, but wondering if others have done the same. I did read the whole 4 pages of 'boreholes' in the pinned section and found nothing on 'hand dug wells'

[sbk]

We had well dug for our avocado plantation as well as for our house. Most locals have hand dug wells of this style. Deep well drilling is frowned upon on the islands as too much deep well usage can reduce the fresh water in the water table and allow for salt water to start soaking in. Not a good thing.

Anyway, ours works fine, the refill rate will depend on your rate of flow. We have several (one originally for our house, the other for the avos out in the middle of the island). The one that is on lower land (our house) refills quite quickly once being pumped nearly dry (don't pump dry as you will then have to prime your pump!) I'd say within an hour. The one at the avos is at a bit higher elevation and probably refills within 3 hours.

We dug our well in the latter part of the dry season so that we knew that even when it was dry it would still have water. During the rainy season the water table is much much higher. I'd say at the very least 2 rings below the top of the water level during the dry season. Ours is three I think.

We have to pump it dry with a high speed pump every few years and my husband then puts a ladder in and climbs down to scoop the muck out of the bottom. You can hire people to do this too, but I think he enjoys it

You have to beware of tree roots trying to creep in, but the rings generally do a pretty good job of sealing it.

[soidog2]

I live in a rice farming community in Chiang Mai and am considering a simple old fashioned hand dug well lined with 1 mtr cement rings. We have surface water at around 3 mtrs now in middle of the dry season as I have observed in other wells. There are few houses near by to polute and nearest septic tank [mine] is 35 mtrs away. Clay soil, so I think most polutants would be well filtered by soil.

questions.....

1] should I worry about polution?? we won't be drinking the water, but will use it for household washing and watering the yard.

2] how much lower than water table should I dig it??

3] and how much recovery time should I expect if I pump it dry??

vague questions, I know, but wondering if others have done the same. I did read the whole 4 pages of 'boreholes' in the pinned section and found nothing on 'hand dug wells'

We live in the Northeast, I have three hand dug wells on the property, use them for; watering the plants , household water, ETC.

Pollution, not much to worry about except if you want to drink it ( bad idea )

Ours are about 7/8 rings down , now dry season the water table is about 4 meters down.

I enjoy having the wells; I keep the municipal water as emergency back up. The water quality is much better than the municipal, especially in the rainy season when theirs turns reddish brown from the floods.

The depth should be at least two meters or more bellow the dry season water table

If you can pump it dry with normal use, it's probably not worth digging it

Best

[gennisis]

I live in a rice farming community in Chiang Mai and am considering a simple old fashioned hand dug well lined with 1 mtr cement rings. We have surface water at around 3 mtrs now in middle of the dry season as I have observed in other wells. There are few houses near by to polute and nearest septic tank [mine] is 35 mtrs away. Clay soil, so I think most polutants would be well filtered by soil.

questions.....

1] should I worry about polution?? we won't be drinking the water, but will use it for household washing and watering the yard.

2] how much lower than water table should I dig it??

3] and how much recovery time should I expect if I pump it dry??

vague questions, I know, but wondering if others have done the same. I did read the whole 4 pages of 'boreholes' in the pinned section and found nothing on 'hand dug wells'

We live in the Northeast, I have three hand dug wells on the property, use them for; watering the plants , household water, ETC.

Pollution, not much to worry about except if you want to drink it ( bad idea )

Ours are about 7/8 rings down , now dry season the water table is about 4 meters down.

I enjoy having the wells; I keep the municipal water as emergency back up. The water quality is much better than the municipal, especially in the rainy season when theirs turns reddish brown from the floods.

The depth should be at least two meters or more bellow the dry season water table

If you can pump it dry with normal use, it's probably not worth digging it

Best

JUst a little story about the well I had dug for me at my new house in Ghana....about a mile away from the nearest village and at the foothill of the local hill.

Down in the village the top of the well water was about 6 ft from the well top....my well was much higher than the village.

So,the digger arrives with his mate,,,two shovels,2 buckets and a legnth of rope.

They start digging to produce a shaft about 3ft dia.

"Fred"at the bottom does the digging,fills the bucket which is hauled up to "George" who piles it at the side....I should tell you that 'Fred" is only 5ft tall,and he is lowered into the shaft each morning and doesnt surface until late afternoon.

After a week the shaft is 15ft and the pile is getting big.

After 2 weeks the shaft is 30 ft and dry!!

Another week its 40 ft and dry.

yet another week... its about 50 ft and still dry!

The following week I hear a lot of yells and panic stations.

"Fred" had hit water...which started to rise up the shaft very quickly and I guess he couldnt swim.

He was hauled up,very wet.

When all the panic and celebrations subsided I had a well 56 ft deep with water about 5 ft deep.

The water was clear,cool and sweet. Quite drinkable.

Only at the end of a very hot dry season did the water level drop to 2ft,and I had no problems with it for the 3 years I was there.

Dispite Ghana being the 'Land of Gold",not a speck in the excavated earth..!!!

[jaideeguy]

"The depth should be at least two meters or more bellow the dry season water table"

So, how do you dig the well past the water level?? Should I provide oxygen and scuba gear to my workers??

Thanks for the feedback......

[Boksida]

35m should be a safe distance away from a septic tank.

If your men encounter water when digging the well, they will normally install the concrete rings and then excavate below them. The concrete rings then follow the well down and if you plug the holes in the side of the rings, you will reduce water influx. The digger can also have a "drivo" pump down there to keep things reasonably dry when digging. If he drowns, you have sufficient water flow anyway and can stop.

There are numerous government departments that have water well drilling equipment - DMR, RID, DPH, ARD, RTA etc. etc. If you know any of these people and they have a bucket auger rig, the well can be drilled and the concrete rings installed in a couple of hours (and they can get the rig back to the yard before they have to share whatever you pay them with their boss).

Check it out here.

Edited January 31, 2009 by Boksida

[jaideeguy]

Well [pardon the pun], another aspect has entered the 'well project'....I just learned the northern Thai spiritual belief that wells are bad luck.

The wife just called our local contractor/spiritual guru and he informs her that wells are 'bad luck' and he doesn't want the job of digging a well. It seems [according to northern Thai 'superstition' that wells will inherit the spirits of some one [the owner of the well] and implies that someone will die so that their spirit will inhabit the well. I volunteered and she got insulted..fearful.

I pointed out to her that the superstition is probably as a result of either kids drowning in wells [happens, but i'll install a lid] or maybe because of simple pollution of wells in urban areas [logical]. One later thought came to mind was that maybe there is a new law against tapping off the top layer of water....makes sense in a heavily populated area. Anyone know of well legalities???

I also pointed out to her that hand dug wellls in Thailand [and all over the world] have been the primary water source for 1,000's of years and 'why are the spirits are angry now?' Thais and logic????

My main reason for digging a well is that our existing wells [drilled] tap into lower aquafers and are high in mineral content....calcium spots on car, windows, dishes, swimming pool, plumbing, plants etc and that water from the surface should have less mineral content.....make sense??

Thanks again for comments......

[jubby]

I'm in the North. Most of the Village had this type of well but have filled them in due to having some sort of municipal water supply.

Can't think why they filled them in as the municipal water supply is very intermittent. Maybe its the spirits thing afterall. Last year I could drain it if I tried hard in the dry season. We have recently dug down another metre and I suspect it won't run dry. The village seems to have one 'Tunnel rat' who digs the Holes, although he's getting on in years. the small bore wells seem to be getting popular here for those not on the ridiculous Village water supply.

Don't worry about the spirits ! , I've rarely seen them and they will keep the locals off your property ;-)

[sbk]

Must be regional, never heard that one here before and every local house on the island that is over 10 years old has a hand dug well.

[jaideeguy]

Wife says/contractor says that there are no more well diggers here in our area any more....another lost art?? all it takes is a shovel and a bucket...I can do it myself, but I have a bad back

I don't worry about the spirits....but I do worry about the wife's belief's in the spirits. Can't count the number of pig's heads, whiskey and cigarattes that we have sacraficed for the spirits..... I feel at peace with the local spirits.

Seems to me that 'urban legend' [law] is getting confused with 'spiritualsm'

tell me this.....does the water from a shallow hand dug well have less mineral content?/ like i described above with my calcium deposit problems??.

[jaideeguy]

What would be interesting to see would be a hydrology study [?] on how these layers of the water table exist here in the big Chiang Mai valley. I'm quite sure that there is some consistency in how deep and how many water levels there are. I have seen three [with my own experience] down to 20+ mtrs. [my deepest well] andthere are any more lower than 20 mtrs, I'm sure.

Maybe a local university could provide some answers???

[Lickey]

OP, you live near Chang Mia, you might or might not be interested in the attached site, ok, it near 8 years old but the situation has probaly got worse since,

Contaminated well/ground water can also cause skin infections, the tap water here is always clear, if it came out muddy-brown i would not shower in it, and just to add, the village clinic is full [including me] in mid october of people coughing and chest complaints, this is when the last lot of heribcide and the first lot of pesticide is sprayed,

I have banned herbicides from the farm now, no more as of last month, Why? the borehole is at the bottom of the hillside farm and all this crap will eventually get into the water and get sprayed everywhere that i dont need it.

My point is Jaideeguy, is have your well water tested, not by some bloke who tells you what you want to hear, but buy a testing kit, i wouldnt want my kids showering in chemical water..

Cheers Lickey..

[Lickey]

Oh flip bum and pooh, forgot to attach site, here it is,,,,,,

http://www.poptel.org.uk/panap/latest/poison.htm ,

[jaideeguy]

interesting article Lickey....but, I don't think our ground water will have much polution as we live in a 1 rice crop a year area and in 1 sq kilometer, there are only 5 households. Also, the fine particle clay soil will filter most pollutants....if there any.

[krading]

Never seen one being dug. Do they add rings on the way down or wait til it's finished and then put the rings in? Concerned about wall collapse.

[brahmburgers]

Never seen one being dug. Do they add rings on the way down or wait til it's finished and then put the rings in? Concerned about wall collapse.

they dig down, and then add cement rings all at once at the end. Have had 2 dug. Each was about 3 meters deep and each had decent recovery rates for about 11 out of 12 months. Later had well drilling truck come out - with 4" pvc casing. Had them drill a lot deeper (30 meters) than they wanted to, because they struck decent water flow at 3.5 meters.

The deep well with 4" casing had sand fill about 30 cm per year. So, after 10 years, had another rig with compressed air come out and blow out 3 meters of sand from the inside of the casing. cost Bt.4,500 and worth it.

Also had a lightning strike 2 years ago which killed my 1.5 hp AC pump. Another deep well of mine, is destined to have a Lorentz DC pump and run on solar panels. Solar is better if you can swing the relatively large initial investment. Plus, it just feels better to be off the grid. Either way, ground your pump with thick copper braided wire.

[krading]

We just had a bore dug on 1 rai of rice paddy (about 14x10x2.5 mtrs) and used that dirt to build up the proposed house site. Struck water at 2 meters. How deep should I sink a well? Probably do it myself (Kii neeow)

[jaideeguy]

while googling about aquafers in the Chiang Mai area, I found this little study on natural polutants in ground water in the CM basin.......

the following was coppied and pasted from

http://adsabs.harvard.edu/abs/2005AGUFM.H23F1493M

Human Health Impact of Fluoride in Groundwater in the Chiang Mai Basin

Matsui, Y.; Takizawa, S.; Wattanachira, S.; Wongrueng, A.; Ibaraki, M.

American Geophysical Union, Fall Meeting 2005, abstract #H23F-1493

Chiang Mai Basin, in Northern Thailand, is known as a fluorotic area. Groundwater of the Chiang Mai Basin has been gradually replaced by contaminated surface water since the 1980's. People have been exposed to fluoride contaminated groundwater since that time. As a result, harmful health effects on dental and skeletal growth were observed in the 90's. These include dental and skeletal fluorosis. Dental fluorosis is characterized by yellow or white spots on teeth and pitting or mottled enamel, consequently causing the teeth to look unsightly. Skeletal fluorosis leads to changes in bone structure, making them extremely weak and brittle. The most severe form of this is known as ``crippling skeletal fluorosis,'' a condition that can cause immobility, muscle wasting, and neurological problems related to spinal cord compression. This study focuses on the problematic issue of the Chiang Mai Basin's groundwater from the viewpoint of fluoride occurrence and current health impacts. Chiang Mai and Lamphun Provinces comprise the Chiang Mai Basin. Fluoride rich granites or fluorite deposits are scattered across the mountainside of the Lamphun Province. Tropical savanna climate conditions with seasonal monsoons bring more than 1,000 mm of annual precipitation, which can prompt weathering of minerals containing fluoride. The Ping River dominates the Basin, and the main eastern tributary of the Ping River runs through the Lamphun Province. The Basin has geological units composed of lower semi-consolidated Tertiary fluvial and upper unconsolidated Quaternary alluvium deposits. The main aquifers are in the upper unconsolidated unit. High fluoride concentrations tend to be observed in the aquifer located in lower part of this unconsolidated unit. We have been investigating two areas in the Basin. These two locations are similar with respect to geological and hydrological settings. However, one area in which groundwater is Ca-bicarbonate dominant has a low fluoride occurrence. Groundwater of the other area contains a high fluoride concentration and is Na-bicarbonate dominant. We will present how naturally-occurring fluoride found in this groundwater has impacted the health of a large portion of residents in the Chiang Mai Basin, and we will explain the mechanism that differentiates Ca concentration, which controls fluoride concentration in groundwater, between different areas in the Basin.

I have seen and heard from locals around my area [Doi Saket] that used to boil ground water for drinking and their teeth were noticably stained, now I know why, and maybe the reason so many of the old people have 'widow's humps'??

[simon43]

Never seen one being dug. Do they add rings on the way down or wait til it's finished and then put the rings in? Concerned about wall collapse.

[\quote]

When they dug the well at our Phuket hotel they added the rings as they went. Basically, a digger was used to excavate the first 2 meters or so. Then a 2 meter diameter ring was dropped into the hole and another put on top. Then a guy stood inside the hole and started excavating by hand. As he removed soil, so the rings started to sink into the ground.

There must be a skill in keeping the rings level as they sink.

As the rings sank into the ground, so another was added on top. So, using this excavation method, the guy who was digging was protected from wall collapse at all times. This manner of excavation was neccessary because the ground is pure sand in this region.

The team installed 14 rings = 14 meters before they hit water. They then continued to dig using a pump to remove the water and were able to get 2 more rings in. So we had a 16 meter deep well with 2 meters of water.

The well has never run dry and the water looks very clear with no smell, even though we are only 400 meters from the beach. The water is not salty at all and is used for our guest room showers/bathrooms.

I don't suggest that guests drink the water, but I clean my teeth in it and never have a problem.

Simon

[Maizefarmer]

I live in a rice farming community in Chiang Mai and am considering a simple old fashioned hand dug well lined with 1 mtr cement rings. We have surface water at around 3 mtrs now in middle of the dry season as I have observed in other wells. There are few houses near by to polute and nearest septic tank [mine] is 35 mtrs away. Clay soil, so I think most polutants would be well filtered by soil.

questions.....

1] should I worry about polution?? we won't be drinking the water, but will use it for household washing and watering the yard.

2] how much lower than water table should I dig it??

3] and how much recovery time should I expect if I pump it dry??

vague questions, I know, but wondering if others have done the same. I did read the whole 4 pages of 'boreholes' in the pinned section and found nothing on 'hand dug wells'

Sub-surface water, that close to the surface is more than likley going to need to be filtered if for domestic use (well, any use come to think of it) - testing it will be a must, because pollution can be rife so close to the surface. Clay is no surity of clean water, in fact its compisition can be very dirty.

how much lower than the water table? - speak to folk in your area who have boreholes and ask them - they'll know how the watertable has moved from season to season over the last 10 years - it can drop 200 - 300% some years, and very little other years

well recovery time? - depends on how fast you pump water from it (pump volume & head relationship - a function of pump type and power) and how fast the well refills (a function of clay density and differential water pressure in the ground) - can't say untill to try it out as it differs from area to area - again, speak to locals with boreholes and wells.

In short: you'll be better off boring a shallow hole and constructing a water storage tower with rings above aground.

Edited February 3, 2009 by Maizefarmer

[slapout]

To the op, Boksida is the in house expert on water wells, drilling, testing, etc here in Thailand. After visiting with him a time or two (sober) he came across as probably having forgotten more than many of us know. Just a observation on my part.