Landscaping Ponds Tips and Formulae and Material Quantities

Calculating your liner size.

Liner Length m/ft = Maximum pond length m/ft + (2 X maximum pond depth m/ft) + 0.3m( 1ft) overlap

Liner Width m/ft = Maximum pond width m/ft + (2 x maximum pond depth m/ft) + 0.3m (1ft) overlap

Before you go to buy a submersible pump for your pond for a fountain, waterfall, filter or a combination of any of these, you must know the volume of your pond.

Volume of your pond in litres.

Average length in metres x average width in metres x average depth in metres x 1,000

A metric cubic metre of water weighs 1 tonne.

To convert to U.S gallons, multiply by 0.26.

To convert to Imperial gallons, multiply by 0.22

Volume of your pond in gallons.

Average length in feet x average length in feet x average depth in feet x 6.25

Volume of a circular pond. ( the diameter in feet x the diameter in feet x depth in feet x π)= Volume of a circular pond in cubic feet.

Volume of a circular pond in cubic feet x 6.25 = Gallonage of a circular pond

Estimating stream liner length

Length on the horizontal x ( 2 x head). The width is governed by the standard widths of liner. A 5ft wide liner, for instance would produce a stream with 2ft 6ins header ponds with 9-12ins outlets. A 10ft wide liner gives you 4-6ft headers with possible 2ft wide waterfalls.

Estimating size of pump for streams or waterfalls. Estimate roughly for 60 galls (300 litres) per hour per inch of sill or waterfall width (just over 100litres per hour per cm ) that can be delivered to the height you require.

Estimating the number of skips required for the removal of spoil from the pond.

((Volume of the pond in feet) x 2) 27 = Volume of spoil to be disposed of

Volume of spoil 6 = Number of large skips to be filled

Estimating the number of blocks for ponds with liners in the ground:

(2 x Length in feet)+(2 x width in feet) 2/3

OR take the measurement from your draped tape measurement around the circumference in feet and multiply by 2/3 for the approximate number of blocks required for the pond.

If you are building in support for the marginal shelf, measure this in feet and add two thirds of the number to the total.

Estimating the number of blocks for raised ponds:

(Height above footing in inches 9) x number of blocks for perimeter (see above) for number of blocks required for the perimeter. Allow extra blocks for the creation of the marginal shelf areas and ponds set in unstable ground.

Estimating the number of blocks for waterfalls and streams. (Approximate rule of thumb)

Head of the stream, i.e. its starting height above pond surface level (in feet) added on to its length and then doubled.

SUMMARY of the ideal site:

It will be in full sun. Nearly all plants associated with water need some direct sunlight to flower, especially lilies.

Away from trees but not too exposed to cold or prevailing winds.

Can be seen from the house.

Where electricity and water supplies are accessible.

Not on low-lying boggy land.

Size and Shape

Keep it simple and more than 30sqft (3.3sqmtrs) and 20ins (half a metre) deep with a shelf for plant support 9inches (23cm) down below the proposed water level.

Further points to remember using flexible liner materials:

Economically it is best to design the pond in one dimension to fit in with the standard widths of liner sizes.

Avoid dramatic indentations in pond shapes and streams, measure around the longest contour to take in the extra liner that is required to accommodate this shape.

Estimating quantities of sand for lining ponds and streams. A metric tonne (1000kg) will cover (very) approximately 10sqmetres at 5cm depth.

Underlay (cheap material for laying under the liner). Take pond liner sizes and add on 10%.

Estimating rockery stone.

Height x width in feet = 1 cwt or 50kilos.

This is the same for estimating the rockery surround or rock edging and the stream face.

Estimating footing materials for blockwork and walling.

Gravel chips of varying sizes down to dust: cement for concrete in a 6:1 ratio,

OR 15 to 25mm gravel chippings, sand, cement in 4:2:1 ratio.

The foundation depth should between and 1/3 of the wall height, and twice the wall width. Estimate 2 tonnes to the cubic metre.

Sand for building. Allow 100kilos for each 4sqmetres faced walling and one 25kg of cement, but more if there is a lot of back filling.

Estimating paving.

Most paving is priced by the square yard or metre apart from crazy paving.

Estimate 1 ton will cover 11 square yards.