Good Information to Serve the Customer ... Priceless
In our view, our customer is as much the person in charge 30 years from now as the one we report to now. The current person or his or her successor, when they need to make plans involving their groundwater supply, should be able to pull out our reports, well logs, etc., and use that information as a point of comparison. What was the specific capacity? The laminar and turbulent well loss? The depth? The yield? What worked? What was a waste of money?
In making plans, predictions and projections, it is often necessary to rely on past information made available to the client by others: typically drilling contractors and other consulting professionals. We are not psychics or distant viewers, able to discern hydrologic properties or fracture densities by feel. I can't even make a twig or wire twitch, so facts and data are essential in advising on groundwater and wells.
Alas, the normal state is one lack of critical information, especially among our small town clientele. Well logs are missing or were never filed. There are no pumping tests, so no one really knows what the well will yield or what it's original (or last post-cleaned) specific capacity was. There is no pump information. There is no flow meter and the well is finished with a water level probe-proof well seal.
The operator, who is in desperate need of one working well, was not here 20 years ago when the last well work was done, let alone here in 1956 when the wells were drilled. The contractor who drilled them is out of business.
Lately, we have been working for a community located in one of the most unproductive parts of our regional Silurian carbonate acquifer. Actually, transmissivity is not so bad, but the limited number of fractures that can be intersected by vertical wells restricts yield to wells. As usual, the original village planners in the mid 1800s failed to consult a hydrogeologist when picking the town site
They need a relatively modest amount of water to serve their population, but the six established wells were not up to it. How much were they capable of producing? Rumors were that wells 1 and 2 were capable of 100 gpm, but they were down to single digits and hundredths of gpm/ft in specific capacity. Fracture development was extensive in a video of well 2. But were they connected? There was no clue.
An abortive use of a nonchemical treatment method had provided no significant improvement in 1999. Well 3 was guessed to be good for 35 gpm, but no information was available. Amazingly, there was no well log on file for this relatively recent public water supply well. Unfortunately, this is not so unusual in our state.
A pumping test conducted prior to cleaning yielded 6.7 gpm at a whopping 0.06 gpm/ft of drawdown. Samples of white sulfur biofilm had the consistency of toothpaste. A well cleaning was planned based on assumptions of what clogging was present and executed at significant cost.
Hopes among the constantly present interested spectators waxed and waned with each step. Finally, a post-treatment step test, which we ran by the book, yielded the results: Specific capacity had been greatly improved (by 26 times at 6.7 gpm), but this squeaky-clean 200-ft-deep well could yield only 15 gpm.
From the step test, we could determine turbulent ("well") loss was very high as the pump tried to draw water through two tight fracture zones. The village administrator sighed, but was glad to at least know what he had.
We now know how to advise the village about water supply - including factoring in that unmentionable option which involves horizontal pipe instead of casing. We're proceeding with the effort to help him know a lot more, and hope for groundwater supply is not extinguished.
We also get calls like these from towns: "Hi Stu, they drilled the well and we did the pump test stuff. When can you wave your hand over it for EPA for us?" The well test results, when I plot them up, do not enlighten me. Instead of the swoosh-shaped constant-rate test plot, it looks like a topographic cross section of the Appalachians.
"Bob (not his real name), what was the flow rate?" A noncommittal answer comes back. "Did you take readings through a drawdown tube?" Affirmative. (Good.) "How long was it?" Unknown. They had trouble getting consistent water level readings. And so forth. This place is only a few miles away. All they had to do is ask and we would have been there to help them avoid producing data useless for estimating well yield and aquifer response.
The step test figures prominently in our efforts to document and benchmark well performance for other wellfield operators. So does the drilling log. We can control the step test by doing it ourselves or advising on technique, but the drilling log is usually a sole-source product of the driller.
We know you're tired and in a hurry, but someday, 30 years from now, someone will be relieved to find your detailed, accurate log in the database, and that log will help someone site, design, construct, or clean a better well, or to avoid a bad mistake.