THE EFFECT OF PUMPING WATER FROM WELLS IN AN AQUIFER

Abstract

Groundwater  is  sensitive  to  the  climate  change  and  agricultural  activities  in  arid and  semi-arid  areas.  Over  the  past  several  decades,  human  activities,  such  as groundwater  extraction  for  irrigation,  have  resulted  in  aquifer  overdraft  and disrupted the natural equilibrium in these areas. This study reports research on the effect of pumping water from several wells in a given aquifer. We have considered, for  simplicity,  an  idealized  one  layer  aquifer  which  has  been  discretized  into  49 identical  blocks  studied  on  the  middle  horizontal  row  of  blocks.  We  have developed a numerical simulating model by discretizing the equation of continuity which we have converted into computer codes. A program has then been written. This program has successfully generated both hydraulic head and velocity profile distributions.  The  results  reveal  that  there  are  less  hydraulic  head  losses  on pumpage from blocks which are far apart, the velocities being least in blocks which are far from the pumpage blocks. The results obtained have a high correlation with those  from  the  well-known  Theis  equation  for  drawdown.  The  results  would greatly help in limiting the usage of a given aquifer with respect to the  maximum number  of  wells  permissible  in  the  aquifer  as  well  as  predict  the  levels  of groundwater in a particular aquifer.