Developed by Tadd M Barrow, Water Quality Extension Educator, School of Natural Resources
A pond is a delicate aquatic ecosystem where multiple interactions affect one another. Knowing the surface area and volume of a pond is critical information to making proper pond management decisions about chemical dose, evaporation/filling rates, fish stocking rates, etc.
Inaccurate measurements of area or volume can lead to ineffective aquatic plant management via under dosing, or worse, overdosing. Overdosing can remove too much plant biomass causing oxygen depletion and can potentially lead to fish kills.
When stocking fish, a pond can only hold so many fish of a given species per acre. Under or overstocking can lead to slowed or stunted growth.
Hiring a professional is the most accurate method to determine pond area and volume; however, a simple estimation of area and volume can be completed by using geometric equations for common shapes that closely resemble that of your pond: rectangle, square, circle, triangle, ellipse, or trapezoid.
Distances needed for each equation can be determined using a transit or laser level (both highly accurate), tape measure, or by counting the steps you take. Calibrate your steps at a known distance, say 100 feet. Count the number of steps required to cover the 100 foot distance. Complete this exercise 2-3 times and then average the number of steps required divided by 100 feet. Now you have a distance in feet equal to one step.
Sloping or uneven terrain can lead to inaccurate measurements. Where possible, conduct all measurements on relatively flat areas. The accuracy of the final output (surface area and volume) is only as accurate as the length measurements used for input.