Before you remove the first cuttings there are lots of items on the checklist to verify. Like making sure you have the right drill rig for the project. If you are working at a remote site, it is important to gather your materials. It is also a good idea to make sure your portable well drilling rig is ready for operation, like setting up the mud pump for mud rotary drilling. When you are eager to get started, these steps can seem tedious, but by taking your time, you will be more successful and efficient when it is finally time to start the dirty work and drill a water well.
Despite your efforts to select an appropriate site, there is no guarantee you will hit water with every bore. That is why most drilling projects should start with a pilot hole. Use the small pilot bit to bore a 4in diameter hole. Depending on your well drilling equipment and site conditions, the time for this process will vary. Carefully collect and record the cutting samples from this exploratory hole to develop a boring log - which will help you design your well if the site pans out.
As you advance your borehole, watch out for signs that you have reached an aquifer:
- Rapid increase or decrease in mud level in the suction pit
- Thinner mud
- Sand or gravel in cuttings
- Mud temperature changes
- ‘Streams' of clear water in the drilling mud as it exits the borehole
- Clay chips that are moist inside when broken apart.
Once you have found an aquifer, use the information from your cuttings to determine the best depth for the well screen. Cut the necessary amount of well screen with a hacksaw and set aside until you prepare your casing.
Go big or go home
You have found water and determined well depth, now it is time to get serious. Using the reaming bit, increase the hole diameter to 6in.
To avoid borehole collapse, complete reaming, casing installation and gravel pack in a continuous operation. However, make sure you have enough fuel, drilling water and time before you start this step.
Reaming creates a lot more cuttings than the pilot hole and will require frequent clearing of mud pits.
Once the designated depth is reached, remove the drill pipe swiftly and install the casing.
Flush out drilling mud. Certain drill rigs, like the LS200, include a casing flushing tool to make this job easier. If your rig does not include this feature, slowly pump clear water down the well casing to force drilling mud out the borehole. This might require multiple drums of water, so be sure to have extra readily available.
With a very low flow of clear flushing water, gradually add the gravel pack to the hole by hand. Use clean, round gravel — like that produced from streams, rivers, and beach deposits — approximately .125 to .25in (3 to 6mm) in diameter. Never use crushed rock, as grains will lock together over time and reduce the flow of water into the well. You will need to have enough gravel on hand to bring gravel up to a point 3ft (1m) above the top of the well screen.
At this point, the danger of collapse has passed, and it is safe to leave the site. Cover the borehole and put away all tools before leaving.
If you have chosen your site wisely and managed to avoid hole collapse by reaming, installing casing and placing gravel all in one go, you are about to find out if your hard work has paid off. It is time to test your well yield.
After measuring the initial water level, use a bailer to draw out as much water as you can in 10 minutes and pour it into a bucket for further measurements. Once you are done bailing, check the water level a second time. If you are able to bale around 2.6 gallons (10L) per minute with little or no drop in water level, congratulations, your well is likely to produce enough water to supply a hand pump. If the well went dry in just 10 minutes, though, do not panic. It is not unusual for an undeveloped well to produce very little water. Repeat the process for two to four days. If the well is still dry with a brief bailing at that point, there is probably not sufficient flow to support a well.
At this stage, you should perform a water quality field test. There are several kits available for this; use the one you are most comfortable with since accurate results are important.
Depending on the results of your tests, you have a decision to make. Do you develop the well and install a pump or start over at a new site? Poor water quality can affect the health and safety of people, plants and animals relying on the well, so use the parameters outlined by the test kit to determine if you move forward with development. Additionally, if your well is not producing at least two to four gallons per minute, it will not be able to keep up with a hand pump, and you are better off trying again.
Quitting time… not quite
Once you have reached a decision, there is still a lot of work to be done. If the well has potential, it is important to protect it from surface contamination by sealing, developing and sanitizing it. If, on the other hand, you chose to look for a new location, be sure to seal the borehole to prevent injury or cross-contamination.
Digging water wells is not always easy, but a rush of cool, clear, thirst-quenching water at the end of the day makes it all worthwhile.