It is Important to Calculate the Volume of Your Moving Water Feature Before You Start Building It

Once you have made the decision to incorporate a water feature such as a stream, waterfall, or series of pools in your yard it is important to determine the size of the feature. This will, in turn, determine the volume of water the feature will contain. It is important to calculate the water volume as this will determine the flow rate, size of pump and filtering system you will need to operate the water feature.

The first factor is to determine the height of the elevation change from the header pool, stream head, or waterfall outlet, to the pool at the bottom of the feature. The 'head' refers to the beginning of the feature where the moving water originates. The elevation of the head from the reservoir pool will determine the head rating of the pump you will require.

If the water flow is less than 2 feet in length you do not need to determine the volume of this section of moving water as it insignificant to your final calculation.

length x width = surface area, surface area x depth = volume

Stream Volume - Average out the width of the stream to determine an approximate width of the entire stream. Take a piece of string and lay it down the bank on one side of the stream. Remove the string and measure its length; this will determine the length of the stream. Multiply the 2 numbers together to calculate the surface area. Measure the average depth including the layer of rock and gravel at the bed of the stream. Multiply depth by surface and you have the volume.

Waterfall - Determining the volume of a waterfall is similar to determining the volume of a stream. You need to think of the waterfall as a vertical stream to determine the surface area. However, to find the depth, measure the depth of the water where it leaves the head and begins its cascading decent, otherwise known as the outlet. Multiply this depth by the surface area and you know the volume of water in the actual waterfall.

Add this figure to the other figures from any pools or streams in the feature as whole.

Take the time to figure out these numbers and you will be on a path to success as you will be able to choose the equipment that will best suit your water feature.