In my article on water sources I discussed what the options are for long term water. In this article I will focus on ground water. Most people in the world get their drinking water from ground water. It is by far more abundant than surface water. Many of you I’m sure are already on well systems and even more of you are on municipal systems that have a ground water source. From the USGS website you can see that there is around 2,526,000 cubic miles of fresh groundwater. Think about that, one cubic mile is one mile long, one mile wide and one mile high. Even one cubic mile is a lot of water. To put it more simply, 30.1% of the world’s fresh water is ground water. Second only to the permanent net ice deposits in glaciers and the ice caps. Needless to say there is a lot of ground water out there. A hydrographic survey will help you find where the ground water is as it is not evenly distributed across the earth (this probably isn’t news to you).
Ground water tends to need less treatment due to the natural filtering from the soil and the slow movement through the soil. This covers the first two steps of conventional water treatment. If you need a refresher check my previous articles, a lot of information has already been covered there.
There are three main types of wells. Dug, bored and drilled. In general they differ in depth, diameter and construction method.
Dug wells are usually shallow (>30ft) and wide (24-48in) due to being constructed with shovels and excavation equipment. Dug wells are prone to contamination right from the construction phase. The equipment needs to be disinfected prior to construction. This includes boots, shovels and buckets. They also are significantly wider which also increases risk for contamination. The final defining characteristic of dug wells is that they are usually shallow, I mean how deep do you really want to dig with a shovel? Dug wells are most prone to contamination. If you have one now, get the water tested. You state or province should have info on how to do this. Because they are the shallowest, they can run dry during dry periods or if there is growth nearby that needs water as well.
Bored and drilled wells are similar. They differ in the equipment, depth and diameter. The last two being products of the equipment. You may have guessed that bored wells are made by boring equipment and drilled wells are made from drills, and you would be correct. Both types of equipment need to be disinfected prior to construction. And both being easier to seal due to the shape of the hole.
Bored wells are in the middle, the can be large and small diameter and have an average depth of 50ft but some in Ontario, Canada can reach 100ft. If you have a bored well constructed, go as narrow as possible (true for all three types).
Drilled wells are the most secure, as they are the narrowest (4-8in) and can go the deepest. The well where I work is 264ft deep, and this is by no means the deepest. The limit here is the depth of the aquifer and the drilling equipment, and the equipment is advancing constantly.
The most important thing you can do with you well is learn where it is. If you don’t know, find out. It is important.
You can reduce the risk for all well types by grouting (if applicable) and sealing, the key is to keep you well watertight as most contamination comes from the surface. It can travel along the outside of the well casing all the way down with zero filtering, or infltrate into the casing through a crack and do the same. Inspecting you well annually for leaks by sight and sound is also recommended. During the inspection remove any debris as debris can cause contamination. Look for any depressions in the soil around your well as they could be signs of water flowing down to your well. Finally compare your well to the construction plans or find a similar drawing from the internet, make sure your well looks how it was designed to look.
Keep the well casing above grade at least 16in. If you mound soil around your well, which you should, keep the casing at least 16in above the mound. The mound should also slope away from the well. If your area is prone to flooding, keep your casing above the estimated/historical high water mark to be more secure. The higher you go, the more support it will need, so build appropriately. You do not NEED to build that high if there is a proper cap/sanitary seal to prevent infiltration. No matter how high you build, install a proper seal/cap, for your protection and that of the surrounding area. Just look up riparian rights to see why that is important.
Keep a 10th zone around your well free from anything but grass and other soft rooted plants (or bare dirt/stone if you are in an arid region). Never use anything you don’t want to drink later within the 10ft buffer zone. Finally, seal any wells no longer in use or ones that have been poorly maintained. It is easier sometimes to build a new one then fix an old one.
There are MANY laws around wells and groundwater if you live in a developed country, and if there aren’t where you are, there soon will be. Always have a professional construct and decommission your well, they are frequently licensed and regulated and using them is often a legal requirement. They will more than likely do a better job at it to. This article is to help you be more responsible with your ground water and in a total end of the world situation give you the basics before you construct one yourself. I will reiterate, building your own well is illegal in many jurisdictions unless you are licensed to do so, so DO NOT BUILD ONE YOURSELF unless the government is gone, and I mean completely gone the penalties can be HUGE otherwise.
Another legality and common sense thing to consider is the volume you pump from your well. Water in the ground provides structure. Removing too much water can mean removing too much support from the ground, you know the ground with your house or doomsday bunker on it. I willl leave you with thoughts of sinkholes and ground subsidence which can happen when too much water is pumped and as usual the final question to you, are there any questions?