Question

Tubewells often dry up after some time. What is the reason for it? How to get water back into the well

Answer 1

Although there might be sufficient groundwater in tube wells, they tend to get exhausted after a period of time due to continuous consumption, evaporation etc.

The practice of enhancing groundwater recharge over and above the natural recharge is commonly referred to as artificial recharge. 

Water harvesting structures like dams, tank, pond etc., do contribute to groundwater recharge as per their site conditions, but site-specific recharge structures are more effective for artificially increasing groundwater recharge particularly in areas where water occurs under water table condition at considerable depth.

 

Many artificial recharge structures, therefore, provide for a pipe to deliver water directly into the aquifer bypassing the overlying unsaturated zone, where percolated water otherwise tend to get dissipated.

Answer 2

Tub well can dry up due to different reasons the main reason is the consumption or usage of the tubewell water . The other contributory factor in this regard is the evaporation of water due to sunlight or temperature.
These tubewell are mostly bored  to underground water resources and take water from underground water sources . This water can be driven by the motors using electricity or diesels like fuels. Most of the modern tubewells are filled with water with help of electric motors.