How to Calculate the Volume of a Well
Why is this important?  The volume of the well is used to determine the amount of plugging material needed.
 The volume is also used to determine the needed amount of disinfectant.
 Assuming the wrong volume of the well could lead to many future problems.
Obtaining Well Dimensions  Diameter of the wellmeasured distance across the inner lip of the well
 Total well depthmeasured distance from top to bottom of well.
 Water depthmeasured distance of depth of water in the well. (Tie a weight to some string and drop it to the bottom of the well. Retrieve the string and measure the portion of the string that is wet.)
Hand Dug Well Example  You have large hand dug well that is 3 feet in diameter and is 45 feet deep. The depth of water in the well is 10 feet.
 The volume of the well is
 V = ((3.1416* 3^{2})/4) *45
 V = 318.53 ft^{3}
 1 yd cubed = 27 ft^{3}
 V = 11.79 yd^{3}/li>
 The volume of the well is calculated by the formula.
 V = ((n * D^{2})/4)* d
 Where:
n = 3.1416 D = diameter of well (feet) d = depth of well (feet)  An abandoned well is 6 inches in diameter, 100 feet in depth, and the water level is 40 feet.
 The volume of the well is
 D = 6in/12in/ft = 0.5 ft
 V = ((3.416* 0.5^{2})/4) *100
 V = 19.62 ft^{3}
Alternate Method  Use Table 1 Plugging Material Calculation Sheet.
 And the diameter of the well.
Well or Hole Diameter  Cement  Bentonite Chips  Inches  Linear Feet  Linear Feet  2  50.3  31.3  3  28.8  13.9  4  16.2  1.9  5  10.4  5  6  7.2  3.5  7  5.3  2.6  8  4  2  9  3.2  1.5  10  2.6  1.3  12  1.8  0.86  14  1.3  0.63  16  1  0.48  18  0.8  0.38  20  0.6  0.31  24  0.4  0.21  36  0.2  0.097  40  0.16  0.078  44  0.13  0.065  48  0.11  0.054  Alternative Method  Bags of cement needed (94 lb per sack)
 100 feet/7.2 feet = 13.8 sacks
 Bags of Bentonite needed (50 lb per sack)
 100 feet/3.5 feet = 28.5 sacks
