How to determine liner requirements:

Length of liner = Length of pond. + twice maximum depth)
Width of liner = Length of pond  + twice maximum depth)
Example:
Pond is 16ft long by 8 ft wide and 2ft maximum depth
Length of liner = 16ft. + (2 x 2ft. depth) = 20 ft.
Width of liner =    8ft.  (2 x 2ft. depth) = 12 ft.
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How to Determine Approximate Gallon Capacity:
For rectangular ponds  ( in feet)
L x W x Average Depth x 7.4 = gallons