Ive got a couple of ways to check the volume in a well as to as far as the recovering amount of water that says how many gallons per minute a well will regain , thus produce not counting the storage capactity. When we get past that I have more questions . How would you do it ?[in detail please]
Thanks ,
Tim.
Replies
Tried to check my well in August a few years ago, put in the pump and let'er run at minimum head, put out 29 gal/min, 12 hours later it was still doing 29 gal/min. Checked timng by time to fill a 55 gal bbl. After 1st 1/2 hour, no further drop in water level, so must be a lake down there, topped off by a higher aquifer.
Was trying to run it dry, then goal was to measure water level, time how long it took to recover to 62% of the drop, which would have given the time constant for recovery. Did not try to get a bigger pump.
Thanks Junkhoud.
So your test evalution didnt show any results because if I understood your post you didnt lower the water level. You lucky feller! <G>
But , if you had lowered the level and you had MY well <G> , how would you have done it sir?
Ill add more later. ..
Tim
1) (smart a$$ answer) take a upper division or university extension course in groundwater and wells.
2) get a good hydrology book. I like Fletcher Driscoll's "Groundwater and Wells". Big and spendy but it has a lot of great info in it. Freeze & Cherry is a standard. Todd is good. Check what you library has and can get. You only need the "pump test" or "well test" chapter.
3) conduct a constant head or constant drawdown test. Get your graph paper and light table. Graph the datapoints, compare to the Theiss curve, grind out the answer. (read above references for details).
4) (quick and dirty) do what junkhound did. Sound the well for static water level. Run a pump for the relevant time period*. Check again for drawdown. Pump rate is pretty close to linear with drawdown. So, fir instance, you have 12 gpm with a 3-foot drawdown, and have a total of 20 feet saturated depth to the pump inlet, then you could produce 12/3*20= 80 gpm over that time frame.
*The relevant time period is whatever the longest you would continously pump (an hour? a day?). Most domestic wells pump for a few minutes an hour. So at my house, I'd run it for an hour. Maybe doublecheck it after two hours and then shutdown. If you have a finite amount of time to do the test (duh!) but want the answer for the infinitely sustainable pumping rate (or for 50 years) like for a municipal supply well, then you need the fancy mathematics in one the references mentioned above.
Good Lord! <G>
Thanks
Tim
Tim, around here we rarely see high production. 2 gpm is normal. What the drillers, and I, do is to blow out the water into a channel. Let the compressor run awhile to remove the reservoir and then stick a 5 gallon bucket into the flow for a minute. Hardly scientific, but suffices.
Requires a substantial compressor, but that's what powers the hammer drills necessary to drill here.
I got 2 gpm when I drilled mine 15 yrs ago on top of this mountain. Even with a very small reservoir we've not had a problem. Normally production falls off after drilling so I don't know what ours now produces.
Had a friend try to tell me that his plumbing was letting air into his lines. Say what? He knew it couldn't be the pump sucking air due to his (initial) 8 gpm production. He finally got somebody to blow out the well. Production was down to 1.5 gpm.
What's up?
PAHS Designer/Builder- Bury it!
There are some different methods for this test, but sometimes your State or county water supply division will have a set of rules and/or instructions for testing a well yield.
I have run a 48 hour drawdown test before. We did it by putting a small pump in the well and determining the average daily demand for the residence (check BOCA Plumbing code for the charts and calculations). Then we set the pump to produce the average day demand by throttling the flow with a gate valve and put a sensor down the well to record the water level. Every half hour for 48 hours (yes, I was paid to sit there and check at 3 am) I'd read the water level and record it on a chart. Then I had to sit there and time how long it took to get back up to the original static level.
In this case we were concerned about neighboring wells being affected by this one well's demand.
Tell me about the sensor you punt in the well to gauge water level please.
Tim
In this case, it was an electronic sensor on a reel of what closely resembled romex, but smaller size and very flexible. You put the end of the wire down the well, and when it touched the water, a light came on back at the top of the well. It was accurate to about an inch or so.
You can find them at Forestry Suppliers, Inc. under the Environmental Science category, look for "water level indicator". Most well drillers use them to get static level.
I purchased a similar item from a company called Hydrolite, it's basically a kit that converts an AA-cell Maglite into a water level indicator. The idea is that you hook it up to a tape or a string, put it down the well unitl the tip hits the water, and the light comes on and shines back up the well at you. Then you read the string.
I used to check septic monitoring wells with a tape measure, put the tape down the well and almost have to guess, or hold a flashlight and tape at the same time and hope I could see ripples on the water surface. With the Hydrolite, I just drop it down until the light comes on and read the tape that's hooked to it. I have measured static level on several water wells with a 300' tape hooked on.
Thanks for an imfomative post .
So you made a living doing this . Cool.
You gotta be thinkin Beverly Hillbillys here ;
Zebco has a reel with a digtital depth feature . A cork on the end of ordinary fishing line in this case reads the levels with out looking in the well.
A water bail is used to extract water . The kind on Grandpas porch well. That is if the well doesnt have a pump.
The time taken to recover is the wanted answer.
Ive learned quite a bit in this thread . like monitoring daily usage . The high gallons blew me away! Im dealing with under two gallons per minute. Well under right now . I had the well pump producing 1/3 per gallon per minute delivering to a storage tank also aka sand filter. My storage is 400 gallons . I sprayed chemical on the yard and used roughly 200 gallons of water. The well ran out of water before it could recover the holding tank! I reset the pump at 1/6th gallon per minute and left the site. I havent been back since Monday.
A little over a year ago I treated the well with dry ice and pumped it to no avail. I followed treatment with dynamite and saw little improvement. I called the well driller and he keeps records . He knew most everything about my well after he looked it up. He hit a vein at 76 feet and took the well to 120 feet. After the dynamite I only have 100 so storage capacity is low. He however told me that it was producing 24 gallons per minute at his test when the well was drilled. He had listed the iron content has very high which it is . Water ran from the well with out being filtered is redish color with visable "chunks " of iron in the water.
This is a cabin well and on weekend usage 400 gallons is plenty of water with no additonal usage other than personal. I have a water tank also I can haul 300 gallons to replenish the tank. The cabin is in the mountains though and hauling water is a pain in the butt for it makes a pick up load by itself and a trailer is too low for gravity filling. The driller suggested drilling a new well right beside the existing.
Tim
"You put the end of the wire down the well, and when it touched the water, a light came on back at the top of the well. It was accurate to about an inch or so."
I always read them to a hundredth of a foot (approx 1/8") - they are consistently that accurate. And, for determining the direction of the groundwater flow, you often need that accuracy (and a minimum of three wells).
But for rough estimate of flow capacity of a well, if your submerged depth was tens of feet, an accuracy of an inch is fine.David Thomas Overlooking Cook Inlet in Kenai, Alaska
Poor mans sensor (good to about 100ft) is a fishing sinker and cork , can fel when the weight is off the line.
Yes. Or something about density 1.0 - when the weight lessens, you're into water. Could be a string around the neck of a soda bottle.
Other options:
"Water-finding paste" from Forestry Products and others. Like a small tube of toothpaste, you smear it on a tape (Stanley 25-footer, fiberglass 100-footer, whatever) with a weight on the end. Turns bright pink in contact with water. If you know depth within a foot (I usually do), you smear the last two feet of the tape. If you know it less well, you smear more or probe repeatedly, deeper each time. With practice, it is good to 0.01 feet
There is also "product finding paste" for petroleum products. Originally these were used by fual tank owners to assess the amount of product in a tank and the presence and amount of water under it. Now they are used to assess all those leaky gas stations. $10 a tube give or take.
Those electronic depth-to-water gauges with the calibrated tape are $500 or so. I've made them from a little buzz-when-the-water-heater-leaks warning do-dah that I got on eBay for $8 (actually bought a bunch). Extened it's wire with co-ax marked off in feet. I use a ruler to interpolate to .01 of a foot.
Once, I put a clothes pin on a string and gauged until the clothes pin got wet.
I've wondered if those sonar "tape measures" for estimators and realtors would work. Would seem that there is no good bounce until the water and then a very good bounce. Only good to an inch but it would be quick and slick. $40 or so.David Thomas Overlooking Cook Inlet in Kenai, Alaska
"Every half hour for 48 hours (yes, I was paid to sit there and check at 3 am) I'd read the water level and record it on a chart."
I prefer to bid the job lump sum and then throw an electronic transducer down the hole. Set to record every minute or whatever you want. Retrieve it later and dump the thousand datapoints to the computer back at the office. You get to sleep in your own bed that way.David Thomas Overlooking Cook Inlet in Kenai, Alaska
Geology detailed question. Am in Seattle area as you know, 1/2 mile north of Cedar river just outside Renton.
At 59 ft down (from 392 ft surface elevation) , there is solid bed of blue clay, overlain by 5-1/2 feet of fine, very uniform grain size black sand. Above that to within 10 ft of surface is cemented hardpan with cobble to boulder size rocks.
I'm assuming that the sand and blue clay indicate where the bottom of the old Puget sound glacier once rested - is that correct, or, what is the correct geological interpretation? WA state well logs at other sites indicate sometimes multiple layers of the blue caly strata, have never gone past the first layer to know first hand.
Given the part of the world you live in, that cemented layer of rocks and gravel could be a mud flow from one of the local volcanoes. You might want to check with the state geology department and see if you are in one of the areas that is prone to that type of disaster. A large chunk of the Seattle area is in serious danger if (when) Mt Rainier becomes active.
Erich
Thanks, that is one possibility, prior research/local data has shown the Mt Ranier mudfolws of the past are all just to the south and Mt. Baker flows to the north, so was left with the glacier surmise. If the hardpan here were any denser, it would be sandstone with embedded basalt cobble, the cobble likely was volcanic.
BTW, did have an interesting exp. with St. Helens, see FHB "great moments..." Nov 1990 issue.
BTW2 - Orting, WA, about 30 mi south of me, even before Katrina, is planning a $2 million staircase from schools, etc. to hilltops out of town, they already have monthly siren drills for evacuation for possible Ranier eruption that would totally bury the town.
The even less palatable possibility is that layer is the remains of a pyroclastic flow. For references, see Pompeii... There is the remains of one about 100' thick in the mountains around here (they are called the Lava Mountains for some strange reason). Its pretty interesting to see the partially melted rock mixed in with the bigger chunks. However, get some pretty nice banded agate out of it.
Erich
I should be sitting here nodding my head and saying "yeah, I could have done that", but I never thought of that approach. However, in this case, an onsite presence was the best method, as the neighbor was overtly hostile and was actively trying to sabotage the results without actually coming over and wrecking something. This was a brand new house on a lot that the neighbor had been using as a lawn, and it was now blocking a good deal of their view of a lake (these were both lakefront homes). The neighbor called the State to complain that the new well was causing a disturbance in their water supply. We had a level meter in both wells.
While I was sitting there, the neighbor did the following: hooked up a lawn sprinkler with several heads and left it run all day and all night, washed three different cars, and threw a party. All the activity did nothing to the new well (unused except for the constant 1 gallon per minute flow test) but wildly fluctuated the neighbor's well. It turned out that their own activities affected their well, to the point where they almost ran it dry. Stupid people.