Water Well Production

One way would be to put a water meter in the line and average the the volume over a period of time.

The problem is: the well is in a remote location without grid electricity. There is currently a small solar pump providing about 2 gpm when the sun is shining. The owner wants to pump more, but there is a huge difference in cost between pumping 3 gpm and 30 gpm... maybe the well only produces 2.5 gpm,, I don't know...

The cheap solution to add a little capacity is another panel, charge controller and batteries, which would double the daily production...

or put in a AC pump powered by a generator...

...but I'm in a pickle not knowing the well's production.

A water meter requires no electricity; it is a mechanical piping component that should ideally suit this situation. For your flow, 1/2" should suffice. A watch and a bucket would also work, but it wouldn't average over as long a time.

It's not the meter, it's the pump. With the current pump the meter will only tell me what the pump is pumping.... I would need a pump capable of pumping more than the well production. I was hoping there was some other way to determine production so the right set up can be determined without trial and error.

And I didn't want to have to baby sit a generator to do it.

How do well drillers determine well production?

Thanks.

Ga to Brich

Small refinement : limit the abstraction to 60% of the determined yield to allow for seasonal and long term fluctuations.

"2 gpm is barely sufficient for domestic use"

Isn't that 120 gal/hr, 2880 gallons per day?

Like 10,944 liters, or 18 days of average household consumption in Australia?

I realize it might be higher in the US, but that high?

Or am I not reading something right here?

I agree, 2 gpm is enough for domestic use except this well is only producing about 6 hours/ day, when the sun is shining. So, 720 gpd. A little low.

Ok, makes more sense,

I assume now you are saying it's a bit light as 720 x 3.8 = 2736 liters/ 600 = 4.5 days and you're factoring x cloudy days, storage make-up flows etc?

But just out of interests; what would be the typical household or per person per day consumption?

But just out of interests; what would be the typical household or per person per day consumption?

I don't know the answer to this, but it's not applicable to this scenario. The site and water use is atypical. It is a remote, off-grid cabin on 640 acres with lots of garden space. So they want to expand the garden space, but need the water to do it. Total available storage is 4500 gallons plus a 1 acre pond.

Ummm Tricky if one doesn't know the plant crop mix, but average is around 2 tons of water for 1 ton of growth. You can subtract from that, if the rain season is coincident with the growing season, at a rate of 1 metre of rain = a metric ton (1000l) delivered (= 500 kg growth @ 2:1)

You can do it in yards; 36" of rain = cubic yard = 1680 lbs = 202 gal which would equal 840 lbs of growth (using 2:1)

If it's Hilda Housewife growing table vegetables in un-mulched beds, you can call it 4 tons of water to a ton of produce, but obviously the total tonnage is not great.

Water per person is radically different on my property (ranch) ~75 l/day/person compared to the city residence, ~150 l/day/person - virtually half.

But if they are not 'country folk' go with the city number, at least initially, till they learn the value.

One hopes the tank is plumbed to the roof, so deducting the annual rainfall is useful if it's fairly even. If not, you need to look at use in the lowest rain months and installing enough storage to capture all in the highest rain months.

It is very common to see tanks on "tree-change" houses over flowing in the rain season and the water truck taking their money through the dry. Similarly a great deal is spent on gadgets and pumping solutions, when just properly tanking every roof would solve the problem (for virtually zero overheads and maintenance).

All the above may have been done and considered, but if not, it may radically change what you want from the pump/well.

Ref the pond; a depth and a fairly simple calculation gives the volume, but you also need rainfall and catchment area. I doubt the well is any use in a pond scenario, but a catchment run off figure will tell you if the pond can cope with the irrigation demand. A simple improvement, like a swale, to catchment topography, can vastly improve the capacity.

I hope this helps. Sorry it's a bit long, but just trying to cover the basic tip of the iceberg of farm water efficiency. If already you know all this - forget I spoke

Thanks for the #'s. I think the plan is to get what we can out of the well and expand the crops accordingly. I'm in California, so 95% of our rainfall is between October and May.

I'm not sure the depth of the pond, but it is the main rain catchment and can be pumped from if needed.

These are 'country folk' for sure. 4-wheel drive road, small cabin, outhouse, seasonal access, etc, etc.

Hmmmm, State of Confusion, semi-arid climate, seasonal use, and need ample well water for crops....

Being "Cheeky" here, but what crops are we talking about? Are they growing "Medicinal Jane"? LOL

No comment...

I'm just the one hired to get the water out of the well.

The minimum flow rate for domestic use is set at 10 l/m in our National Standards for water services ,

At 4.5 l per imperial gallon 2 gal will be only be 9 liter per min.

I will start checking pipes etc when my flow reduces to 10 l/m.

US gal is 3.78541 liters - _{not that helps}

Exactly.. thats why I kept my reply simple, as I don't the OP knows what he has. The well production is ample for the house, pigs, cattle and chickens, unless he's trying to water the farm too!

I was faced with exactly the same questions regarding a well we built in this country and there are more than a few factors of concern. Unfortunately there doesn't seem to be any reliable way of bypassing the pumping test. You need to get a pump that is big enough to reach the wells draw down capacity. That point is where you are in equilibrium with how much water comes into the well and how much you are taking out. When the well is not in use you will have a certain water level. We measured ours with a fishing line and a plastic bottle with some rocks in it. The bottle goes down quickly until it hits the water then it floats and stops. Then we marked the string, reeled it back up and measured it. The plan was to use a test pump like the SUN PUMP 2HP DC submergable with its controller. Pick the right pump from the SUN PUMP charts as depth has a great influence on which model you need. You need to consider the vertical distance from the well water level to your storage tank to select the model. The intelligent pump controller knows if the pump is running dry because of how much current its drawing. It will automatically shut down, wait awhile for the well to fill and try again. The SUN PUMPS operate at a variety of DC voltages so you would lower the pump into the well about 10 feet deeper than the measurement you got and power it up with a DC power supply instead of solar panels. If the pump starts up but soon runs dry you can try lowering it a bit more or turning back the pumping rate until you find that perfect point where the well level no longer drops. At that point measure your GPH rate.

Another thing which will upset your readings will be the time of year. Some wells go completely dry part of the year and produce tons at other times.

Probably the most cost effective method would be to get a separate company to do all this for you.

John

Support the string(pipe&pump) with load cell to take weight measure. Hook pump VFD and adjust pump volume so there no change in weight. Volume can be computed from pump displacement and RPM. Don't know if this would be cost effective but it's efficient other then well production can change with seasonal rain fall.

Measure the height of the water line. If you know how deep your pump is you can know the volume of water over the pump. Run it a couple of hours and measure it again. If you cannot measure the length of the well you can try doing it by preassurising the well. After reading the manometer or pressure gauge you can use the following formula:

P=Dgh

Where P is the pressure, D is density of water and g is the gravity constant.

It could work you know.

In basic simple terms;

1. Measure the static level of the aquifer. Well pump off for at least one hour.

2. With the pump on, measure the drawdown. Wait at least one hour after pumping starts.

You need a sounding cable to perform these measurements. Contact a well driller.

From these two bits of information, you can formulate the yield of this well and then you can determine to reduce pumping or increase pumping with out adverse effects on the well.............Specific capacity is equal the pumping rate divided by the drawdown.

Not sure on this........consult well driller..............good luck

A simple, maybe not very accurate method, measures the the amount of water able to come out of the well by determining the amount of water that the well can absorb.

You will need about 275 gallons of water in a tank which can discharge into the well this is to fill the well to the brim.

Another smaller drum or tank with a known quantity of water in it discharges into the well at a rate which will just maintain the level at the collar of the well.

The known quantity of water divided by the time it took to discharge into the well will give you an approximation of the yield of the well.

Thanks for everybody's response.

I ordered a 3/4 hp pump to give me up to 10 gpm. In addition I have ordered a 'pump saver' which shuts the pump down if the current jumps up (indicating the water level has dropped below pump level). I'll babysit the pump and choke the supply line until the water level keeps up with the pump.

Thanks again.

The pump saver may work in the opposite way you wrote here. With no water the demand on the motor drops so the current jumps DOWN.

John

Yes, right. No load.... mistyped.

So glad you all spotted the typo..

simple rules to remember when talking about pumps....

1. Low current.. low production, or none.

2. High current..high production

3. High well head pressure.. low production..you know the rest

4. Low well head pressure...high production. apply point 2.

You need to conduct a well yield (capacity) test. Usually, this is conducted by a water well driller who knows the groundwater hydrology history of your area. I'm afraid there is not much else you can do other then testing the well...there are no shortcuts available.

Here is an excerpt from:

USACE / NAVFAC / AFCESA / NASA UFGS-33 20 00 (April 2008)

--------------------------

UNIFIED FACILITIES GUIDE SPECIFICATIONS

DIVISION 33 - UTILITIES

SECTION 33 20 00

WATER WELLS

from PART 3 EXECUTION

3.5.1 Capacity Test

**************************************************************************

NOTE: This test should be used to verify that the

well is developed properly and will produce the

required yield. Test pump should be capable of a

range of pumping rates, varying from about 50

percent to about 200 percent of the design capacity

of the well. Since there are a wide variety of pump

test methods, the designer should refer to a good

water wells reference book (such as "Ground Water

and Wells," by Fletcher G. Driscoll, published by

Johnson Well Screens, 1986 ) for test procedures

which best apply.

**************************************************************************

Furnish and install an approved temporary test pump, with discharge piping

of sufficient size and length to conduct the water being pumped to [point

of discharge][_____], and equipment necessary for measuring the rate of

flow and water level in the well. An [8] [_____] hour [constant-rate]

[step-drawdown] capacity test shall be run with the pumping rate and

drawdown at the pump well and observation wells recorded every [[30]

[_____] minutes] [1/2 minute during the first 5 minutes after starting the

pump; then every 5 minutes for an hour; then every 20 minutes for 2 hours.

From this point on, readings taken at hourly intervals, until the water

level stabilizes, shall be sufficient].[Observation wells (piezometers)

shall be read on the same schedule as the pump well.] [During the

step-drawdown test, the pumping rate shall be increased in steps at

[regular][[2][____] hour] intervals. Specific capacity shall be measured

for each step.] The test shall begin at the rate of [the expected capacity

of well] [[_____] L/s gpm] and at least that rate maintained throughout the

duration of the [test] [step interval]. [The well shall be "step" tested

at rates of approximately [1/2, 3/4, 1 and 1 1/2] [_____] times the design

capacity of [_____] L/s gpm.] If this capacity cannot be maintained for

the test period, the capacity test shall be terminated and the test hole

drilled deeper or relocated as directed. When the pump is shut off, water

level readings shall be taken during the rebound period for the same

intervals of time as the drawdown test. The record of the test, in

triplicate, shall be delivered to the Contracting Officer.

Hope that this helps. It's a good benchmark for starters. Your first step is to contact a well diller who is local. If you need further advice then please ask and I can send you additional information that I have stored on CD's here in my office.

===Signed,

CaptMoosie

very informative, but not really applicable to this tiny water well as he does not have the facilities to conduct this type of injection test....I resisted the urge to detail all that info after reading the OP posts, as I decided it was not applicable, the best option is KISS.

Thanks CaptMoosie.

Very interesting and VERY on point. GA

pump the well dry. wait an hour. mearsure the amount of water it takes to run it dry again. if you can't run it dry, i would'nt be concerned.

One thing to keep in mind about the well capacity as you need to meet or exceed the PEAK water demand flow rate. You usually determine this on FIXTURE UNITS vs. FLOW chart. In other words, the fixture unit count is determined on the sum total of the weighted average of flow required by each water using fixture (as well as the type....ie, type of flush valve, water conservative shower head, etc) in the dwelling "on" simultaneously. The flow determined by using the proper chart curve results in the peak flow rate that the well pump and hydropneumatic tank(s) system must meet o exceed.

Also, make sure you do not overdraw the aquifer by pumping excessively, or other words you may not be able to recharge the well fast enough prior to the next "pump on" duty cycle. You never want to overdraw a well s it leads to a whole host of problems, including fouling of the well screen (if present), the pump and it's discharge line, and poor water quality increase like elevated iron bacteria presence, iron and manganese constituent levels.

If you need the fixture unit vs. flow rate chart I can dig it out of one of my reference books, scan it, then send it to you or post it here. It's an invaluable engineering source to have when designing water supply and wastewater disposal systems.

If you cannot obtain the necessary water production flow rate out of the well you may have to drill deeper. I presume this well is founded in bedrock due to it's depth? If so, you may have to hydrofrack rock at the bottom of the well in increase yield capacity.....not cheap by any stretch of the imagination, but may be your only alternative to drilling a parallel well to obtain the required production rate.

Let me know how you want to proceed as I'm more than willing to step forward and give you some invaluable advice if needed.

Have a great sunny day, but stay Kewl in this heat wave!

Thanks for the offer, but the home on site is not standard... I don't think there is anything plumbed in the house. Outdoor kitchen, outhouse, etc... Very primitive by modern standards. Summer use only with a big garden.

Not hot here... cooler than normal, 70's... it might hit 80's today.

I'm gathering from #34 & #35 ^{_{(and ignoring the predictable rampant banality intervening)}}, that it's winter rain and summer (70's - 80 F) occupancy and agriculture.

Indeed this is a supply and demand conundrum.

Temp indicates not a huge evaporation issue with the pond, but as deep as possible for the surface area is obviously more efficient for storage and long term salinity build up.

The 'activity' does change the 'mix' for the well supply. Ideally you would want the domestic demands fulfilled during the rain. I.e. sufficient is in store for the occupancy needs, so no additional demand falls to the well.

Should the pond be reduced below useful levels, the well pump is then serving 'irrigation mass flow' capacities. _{(& I'm assuming here, domestic demand is winter storage catered)}

You may well be looking at filling several of the tank size mentioned - (when solar allows)

I would certainly take a hard look at pond capacity improvement as it would be a very good well to supply other than 'hobby' agricultural demands for months.

Nothing is more depressing than losing a crop, just maturing to harvest, for lack of an acre inch of water. (27,154 US gallons) <just hinting at 'scale']

GA. I'll take your information to the land owner. The pond has not been developed as a water source, only for visual enjoyment and as a firefighting water source. The temp's are lower than normal right now; the typical temperatures expected this time of year is in the 90's, so I think evaporation is an issue, especially with the relative humidity very low.

And thanks for bringing the thread back to topic.

I have the pump and components coming in this week and will install next week. I'll report the results when I have them.

On a side note, when I dropped the solar pump three years ago the land owner said the well was 100 feet, of this he was sure because he paid by the foot to get the well in. When I dropped the pump it ended being over 200 feet deep. A short time before I placed the pump there was a moderate earthquake with an epicenter 1/4 mile from the well site. Is it possible for the quake to have opened a large cavity?

I'd be guessing on the quake aspect, but they usually drill till the right sort of stuff is hit and not much further, so it's quite feasible the quake collapsed out the foot into a underlying void, or hydraulically split a fissure. Might be an idea to get the water retested if it hasn't been since the quake.

I took the temp as altitude influenced, thinking I'd get a rough location for rainfall volume, soil profile, general topography, so probably serendipitous work interfered.

If it suits, PM me such things and it may help me sharpen up the options. One side or the other of a hill can make a big difference.

_{No problem with 'back on track', while there is interesting stuff to delve, my silly side (at least) is on hold.}

I'll be dropping the pump on Monday. If the landowner is interested in more analysis of their setup I'll drop you a note. I'm not too concerned about a breach in security... no one from out of this area is going to wander these hills on private property and know where the hell they are.... with or without GPS and such.

I thought I would get this update in last week, but the owner failed to get a generator to me in a timely manner. So the well pump is up and running as of this morning. When I pulled the small solar pump it was in 10 feet of heavily silted water... clogging the screen; which was the real problem with their daily water production.

I placed the new pump 12 feet above the old pump, which is now in 10 feet of water. I ran the pump with pump saver into a bucket with the pumpsaver on a 5 minute cycle. I ran this against my chronograph and choked the gate valve down until the pumpsaver stopped kicking the pump off. Lo! and Behold! the well production rate is 2 gpm.... the same volume the solar pump was set for....

When I set the solar pump it was well above the bottom (I don't know by how much)... any guess as to the cause of heavy sedimentation? The water today started brown, then ran grayish. I think it was just air bubbles causing the gray, but I'm not sure. There is a lot of serpentine in the area.

GA

kevinm,

Thanks for your well thought out reply(both of them). I'll forward your information and see if the owner wants to pursue the matter further.