**Calculating Pond Volumes**

Need for calculating pond volumes

1.) Knowing your pond volume will help to determine how many fish you can keep.

2.) Help to determine partial water exchanges.

3.) Essential in determining levels of conditioners, and medication treatments.

4.) Determination of flow rates and size of UV filters.

5.) Determination of flow rates and size of biological filters.

6.) Determination of flow rates and size of particle filters.

**Ways to measure water volume while filling a pond
**

1.) The easiest method is use of a water meter while pond is being filled.

2.) Another easy way is to calculate the time it takes to fill a 5 gallon (20L) bucket with a garden hose with a constant flow rate. If you are on a well system water pressure will vary so it would be best to take 5-8 samples at the various pressures and average them.

Use this time figure as a standard rate for 5 gallons and record the time in seconds that it takes to fill your pond using the same garden hose. Use the following formula to determine the total volume of your pond.

**Volume of pond = Time (seconds) to fill pond X Volume (gal or L) of bucket ( gallons or liters) Time required to fill bucket in seconds**

Example: Volume = 770 seconds X 5 gal divided by 20 seconds

Volume = 192.5 gallons

**Ways to measure water volume of filled ponds**

1.) Square and rectangular ponds with the same depth over the entire pond.

**Length(L) X Width(W) X Depth(D) (inch/feet or cm/meters) X 0.785 = Vol. of Pond**

**Example: 9’(2.74 m) L X 6’(1.82 m) W X 2’(0.6 m) = A volume of 108 cubic feet or 3 cubic meters**

2.) Square and rectangular ponds with irregular depth over the entire pond. In this case at least 10 samples of depth should be taken and averaged.

**Length X Width X Average Depth (inch/feet or cm/meters) X 0.785 = Volume**

3.) Round ponds with the same diameter from top to bottom and the same depth over the entire pond.

**Diameter X Depth (in inch/feet or cm/meters) x 0.785 = Volume
**

4.) Round ponds where the top and bottom diameters are not the same but depth is the same over the entire pond. T = Top, B = Bottom

**Diameter (T) X Diameter (B) X Depth (inch/feet or cm/meters) x 0.785 = Volume**

5.) Round ponds where the top and bottom diameters may or may not vary but depth varies. Determine an average depth by taking at least 10 samples and use formula 3 or 4.

6.) Irregular ponds are complicated. The best and most accurate way is to measuring the amount of water needed to completely fill them.

**Conversion numbers.**

1.) Cubic feet from inches Total inches divided by 1728 = cubic feet

2.) Cubic feet to gallons Cubic Feet x 7.48 = U.S. Gallons

3.) Cubic meters to liters Cubic meter x 1000 = total liters

4.) Cubic feet to cubic meter Cubic meter = 35.31 cubic feet

**Calculating the size of pond liners**

Custom liners for irregular shaped ponds are very expensive for average home owner. However, when selecting a liners we recommend using a flexible soft liner made of PVC or EPDM rather then a more rigid type like high density poly vinyl. The required size of the liner for an irregular shaped pond or standard shaped ponds follows this simple formula.

**A.) Length of the liner should be the overall length of the pond plus twice the maximum depth.**

B.) Width of the liner is the overall width of the pond plus twice the maximum depth plus 2’

**Example: a pond with an overall dimensions of 6’ x 12’ and a depth of 36″ would require a liner that is 14’ x 20’.**