Drilling your own well – the boring details
Published 11/04/2012 | 10:48
FOR MANY new home builders who don't have easy access to mains water,the only avenue open tothem is to bore a water well before proceeding with their building programme.
Water is one of the most useful and valuable resources, and fortunately is extremely abundant in Ireland, with the most obvious sources in the countryside in the lakes and streams.
However some of these sources have serious drawbacks as fresh water supplies because of hauling costs, algae, dirty colouration and the danger of pollution. Thankfully there is a large amount of water underneath our feet in the ground. Being hidden it is considered somewhat mysterious by many, but groundwater has many advantages over other resources because of its freedom from contamination, local availability and low constant temperature.
A water well is any hole dug into the earth which reaches the water table for the purpose of extracting water. Strictly speaking, a dugout which intersects the water-table is therefore a well. Generally however, we think of wells as being a few inches to a few feet in diameter.
No drilled well should be less than six inches in diameter, because smaller ones seriously limit production and make repairs and servicing of pumping equipment very difficult.
Above the minimum size, doubling the diameter only increases well yield by 15 to 25%. Hence for the quantities of water needed by most farmers and domestic users, a well should rarely need to be over six inches in diameter, but for industrial users, a well needs to be much larger.
Wells are drilled into two types or aquifers: water table and artesian. A water table well penetrates an aquifer whose lower surfaces is relatively impermeable confining the bed, and whose upper surface is the water table itself. When pumping lowers the water level of the well, the water table drops in its vicinity.
An artesian well does not necessarily flow, contrary to popular thought. It penetrates an aquifer whose upper and lower boundaries are both confining beds.
Water table wells are usually shallow and more susceptible to contamination, but their yield is frequently greater than from artesian
In selecting the site for your well, convenience of access should be considered.
Also remember that wells in low areas do not have to be as deep as those on knolls.
Avoid drilling down near, barns, privies or septic tanks. These can readily pollute a water supply. Assuring the purity of well water should be the most important consideration.
Also remember the most satisfactory pump for a borehole is the submersible type, which involves no suction pipe or foot valve.
Sizes range from 1.3 horse power to 100 h.p. and givevolumes and pressure suitable for needs ranging from private houses to factories.
Pumps can be installed to operate automatically, using a client's existing pipework and with pressure to suit individual requirements.
Where volume storage of water is required the switching can also be automatic through a float switch in the tank.
Pumping costs are usually dictated by the depth of the well – deeper wells requiring more horse power.