Can you fill a well If the water table is 30 metres down is it possible to fill the well shaft to the top?

Answer 1

Only if you seal the well off from the water table. Otherwise you will have to put enough water in the well to raise the water table 30 meters.

A well can be filled-in using earth or a mixture of earth and "safe" material such as clean broken bricks, etc. If anything is used which could poison or otherwise contaminate the water table that would be dangerous and probably illegal too. (It depends what your local Environmental Protection laws say.)

Just by using water from somewhere else it is impossible to say if the well shaft could be filled to the top - that is like asking "What is the length of the string in that ball of string?" Unless you made the ball yourself, from a known length of string, or it says the length on the manufacturer's label, you can only find out the length of the string by unwinding the whole ball and measuring the length of the string!

Bear in mind that the well might be fed from water-bearing rocks or from an underground cavern with a lake in it. You might try pumping-in many thousands or millions of gallons of water and would still not be able to fill the well - so don't ever plan to raise your local water table just by pumping water into it! The position of the water table is a natural phenomenon, it results from the location of aquifers (water-bearing rock layers), the height of the site above average sea level, etc. In short it all depends on where the site "is" within its surrounding the terrain.

So, as the first part of the other response to this question says, the is "Yes, but only if you seal the well off from the water table." If you do that you will in effect be creating a tank to hold water that you put into it from somewhere else: rainwater or water from a mains supply using a hosepipe, etc. That tank will then hold the new water above the existing ground water table.

If the question is asking how the water down at the bottom of the well can be brought to the surface, the is "Yes, but only by using something to lift the water up to ground level." The old-fashioned way to do it is to drop down a bucket on a long rope so you can haul up the bucket full of water. The modern way is to use a "lift pump".

Water cannot be raised using a suction pump from 30 metres (100 feet) below ground level. The maximum height you could raise water using a suction pump depends on the water temperature and the atmospheric pressure at the site. For most places on Earth the greatest height it is possible to raise water using a suction pump is usually reckoned to be just under 9 metres (30 feet).

Why is that so? If the water temperature was well above freezing, say 20oC (68oF) and the atmospheric pressure was, say, 1 Bar (= 1000 milliBars) then the pressure present underneath a column of water about 9 metres (30 feet) high would be the same as the pressure of the atmosphere. So that height is just a bit more than the maximum practical height you could raise water using a suction pump. If you tried to raise the water any higher all you would be doing is creating a vacuum in the pipe!