Approximate Gallons of Water in a POND
Length x Width x 80% x Avg. Depth x 7.48 = total gallons
*The basin takes up approximately 80% of the actual SQ. FT.

Approximate Gallons of Water in a STREAM
(Length x Width x .25 (Depth) x 7.48) = Gallons in the stream.
*You need 2x the amount of water in your basin

Rock Calculation for the POND
Length x Width ÷ 40 = Tons of boulders
***Using a 1:2:1 ratio***
For every (1 TON) of 6”-12” rock, Get (2 TON) of 12”-18” and (1 TON) of 18”-24”

Quantity of Boulders used in a STREAM
For Every 10’ of STREAM = (1 ½ TON) using 1:2:1 RATIO from above

Quantity of GRAVEL Used in the POND
Pond Gravel = 30% total tons of pond boulders

Quantity of GRAVEL Used in the STREAM
Stream Gravel = 30% total tons of STREAM Boulders

Approximate Gallons of Water in a PONDLESS® WATERFALL BASIN 
With Stone
Length x Width x Depth x 2.2 = Gallons in the Basin 
With Large Matrix 
Length x Width x Depth / 4.3 = Number of matrix used 
Number of matrix used x 32 = Gallons in the Basin 
With Small Matrix 
Length x Width x Depth / 2.3 = Number of matrix used 
Number of matrix used x 17 = Gallons in the Basin

Evaporation Rates

You can expect 1/2% - 1% of the total gallons per hour, per day to be lost to evaporation

For example:

3,000 GPH pump

1/2% = 15gallons/day

1% = 30gallons/day

Make sure to estimate the flow rate after head pressure loss, 3,000 GPH pump may only supply 2,500 GPH or less, this will make a difference.

The variations are used according to the site conditions, full sun and full wind will be 1% a sheltered pond will be 1/2%.

These numbers are an average; it will fluctuate throughout the season.

This is also for the Midwest; it will work for most of the country except Arizona and other hot, dry climates.

Evaporation continues to increase as the amount of water flowing thru the atmosphere increases along with the increased splashing and vaporization of water as it crashes over boulders.

The next question or answer you need is how much water is 1" of water loss in a given pond.

11'x16' pond = 176 sq. ft. If it was a rectangle x .85 for irregular shape = 150 sq. ft.

150 x .62 gallons/sq.ft. X 1" deep = 93 gallons

3000 GPH pump x 1/2% = 15gallons x 7 days = 105 gallons/week or 1" of water loss/week.

Try it on your personal pond or other pond your familiar with to double check the calcs, adjust as necessary.