3. Constructing fish ponds

How large should your pond be?

48 It is good to start with a pond greater than 300 square metres. Such a pond will produce enough fish for food. It will also produce fish for sales and additional cash income.

49 For example, if you build a pond 20 by 20 metres, the pond will measure 400 square metres.

50 A square or rectangular pond is easiest to build, but your pond can have a different shape to fit the size and shape of your land.

Figure 33

Figure 34

How to build a 20 by 20 metre pond

51 First mark out a big square on the site you have chosen, about 26 by 26 metres. Mark the corners with pegs and run a string between the pegs to show where the outside of the banks will be.

52 Clear the big square of all trees, bushes and grass and take away as many big roots as you can.

Figure 35

Figure 36

53 Take away about 20 centrimetres of topsoil from all over the square. Put the topsoil aside. Later you will put it back on the top and outer sides of the banks.

54 Now mark out a smaller square inside the big square, about 20 by 20 metres. Mark the corners with pegs and run a string between the pegs to show where the inside of the banks will be.

55 The bottom of the bank in the shallow part of your pond and along the sides should be about 1 metre from the upper end and sides of the small square.

Figure 37

Figure 38

56 The bottom of the bank in the deepest part of your pond should be about 2 metres from the lower end of the small square.

57 Now mark out a third smaller area in the centre of your pond, about 17 by 18 metres We will call this the central area. Mark the corners with pegs and run a string between the pegs to show where the bottom of the banks will be.

58 Be sure that ail the pegs and strings marking the 26 by 26 metre square, the 20 by 20 metre square and the central area are set up as shown in the drawings.

59 Now you are ready to begin digging out soil from inside the central area to build the banks of your pond.

Figure 39

Figure 40

61 Shared work is lighter work. When we work together with our neighbours, the work is easier and faster.

62 Begin digging inside the central square at the upper end of your pond. Dig about 20 centimetres deep. As you dig towards the lower end, dig a little deeper. When you get to the deepest part, at the 2-metre string marking the central area, you should be digging about 30 centimetres deep.

63 As you dig out the soil, put it between the lines marking the 20 by 20 metre square and the 26 by 26 metre square, where the banks will be. Put it nearest to where you are digging. This way, the banks will be higher and wider as you move toward the lower end.

64 When you come to roots, take away as much of them as you can and put them aside.

Figure 41

Figure 42

65 Whenever the loose soil you put on the banks reaches half as high as your knees, pack it down tightly. You can do this by beating the soil with a heavy plank, a length of tree trunk or an earth tamper.

66 When you are digging, keep the slope of the pond bottom as regular as you can. It should slope gently down from the upper end to the deepest part. The bottom of the pond should have slopes like those in the drawings.

67 Begin again to dig soil out of the central area. Dig 20 more centimetres from the upper end and 30 more centimetres from the deepest part. Put the soil on the banks and pack it down tightly as before.

Figure 43

Figure 44

68 Now begin again, for the third and last time, to dig soil out of the central area. Dig 20 more centimetres from the upper end and 30 more centimetres from the deepest part. Put the soil on the banks and pack it down tightly.

69 When you have finished digging out the central area and you have put on the banks all the soil that you have taken out, you will have a hole 17 by 18 metres with straight sides. Now it is time to shape the banks.

70 Dig the soil away from the edges of the central area to form the slope of the banks. Put this soil on top of the banks and pack it down tightly.

71 The inside of the banks should slope less steeply than the outside. The drawing shows you what the banks should look like when they are finished.

Figure 45

Figure 46

72 The top of the banks should be about 1.5 metres wide and should be straight and flat all the way around the pond.

73 Get the 20 centimetres of topsoil you took away when you began digging and put it on the top and outer sides of the banks. Plant grass on the banks. Banks covered with grass last longer.

74 The bottom of your pond should be about 1.1 metres (110 centimetres) from the top of the banks at the shallow upper end and about 1.4 metres (140 centimetres) from the top of the banks at the deepest part.

75 Be sure that the bottom of the pond is fairly smooth and regular.

Figure 47

Figure 48

76 Now dig a ditch in the bottom of the pond from the centre to the lower end. The ditch should be about 50 centimetres wide and about 20 centimetres deep. This ditch will help you drain out all the water when you empty your pond.

77 When the ditch is finished, remove all loose soil and other trash from the bottom of the pond.

Building bigger ponds

78 If you want a still bigger pond, you can build one of 20 by 30 metres 20 by 50 metres or even 30 by 50 metres The banks of ponds this size should also be 1.5 metres wide at the top, but because these ponds are bigger and deeper and hold much more water, the banks should be stronger at the bottom than the banks you built for your smaller ponds.

Figure 49

Figure 50

79 Since you will be digging bigger and deeper ponds, you will take out more soil. Put all the soil you dig out on the lower part of the banks. This will make them thicker and stronger.

80 The drawing below shows you what the banks should look like when you are finished.

81 However, if you build ponds of this size, you should build them a little deeper. They should be at least 0.75 metres (75 centimetres) deep at the shallow end and at least 1 to 1.2 metres deep at the deepest part.

Figure 51

Figure 52

82 If you live in a place where the temperature falls below 20°C, make your ponds 1.5 to 1.8 metres deep. The water will be warmer in the deepest part and your fish can go there during the colder part of each day.

Note: When ponds are side by side, you will need only one bank between two ponds. If you are building two ponds side by side at the same time, you can make the top of the bank between them 1 metre wide instead of 1.5 metres

Figure 53

Figure 54

Summary
YOU HAVE LEARNED HOW TO BUILD YOUR FISH PONDS

The pond should

• be greater than 300 m² to produce fish for food and cash
• have a square or rectangular shape
• be shallow, with water depth from 60 cm (upper end) to 90 cm (lower end)

The banks should

• be 50 cm higher than the water on top
• have a good slope on the sides
• be built with soil tightly packed

Build your pond in successive steps:

• clear all vegetation, rocks, etc. from the area
• remove the top soil and keep it aside
• mark the limits of the inside banks at ground level
• mark the limits of the inside banks at bottom level
• dig inside these last limits by layers of 20 cm (upper end) to 30 cm (lower end)
• use this soil to build up the banks, layer by layer and tightly packed
• form the inside slopes of the banks
• form the outside slopes of the banks
• add topsoil on top and on the outside slopes of the banks
• inside the pond, dig a small draining ditch