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close this bookBetter Farming Series 29 - Freshwater Fish Farming: the Pond (FAO, 1981, 43 p.)
close this folderBuilding a bigger pond
View the documentHow to make your old pond bigger
View the documentHow to build a new, bigger pond
View the documentThe inlet
View the documentThe outlet
View the documentA better outlet
View the documentThe overflow
View the documentA siphon
View the documentScreens

How to build a new, bigger pond

49. There is much more work to do when you build a big pond than when you build a small pond.

50. First mark out a big square on the site you have chosen, about 21 by 21 metres. Mark the corners with pegs and run a string between the pegs to show you where the outside of the banks will be.

51. Clear the big square of all trees, bushes and grass and take away ail the big roots you can.


Clear the big square

52. Take away about 20 centimetres 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.


Take away topsoil

53. Then mark out a small square inside the big square, about 15 by 15 metres. Mark the corners with pegs and run a string between the pegs to show you where the inside of the banks will be.


Mark out a small square

54. 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.

55. 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.


The bottom of the bank

56. Now mark out a third smaller area in the centre of your pond, about 12 by 13 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.

57. Be sure that all the pegs and strings marking the 21- metre square, the 1 5- metre square and the central area are set up in the way shown in the drawings.

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

59. Ask your neighbours to help you to dig your big pond. Then you can help them in turn to dig their ponds.


Dig the big pond

60. Shared work is lighter work. When we work together with our neighbours, the work is easier and better.

61. Begin digging at the 1- metre string marking the central area at the upper end of your pond. Dig about 20 centimetres deep. As you dig toward 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.

62. As you dig out the soil, put it between the 15 by 1 5- metre square and the 21 by 21- 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.


Put soil on banks

63. When you come to roots, take away as much of them as you can.


Take away the roots

64. 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.


Pack down the soil tightly

65. 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 these in the drawings.
66. 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.


Put soil on banks

67. 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 form the deepest part. Put the soil on the banks and pack it down tightly.

68. 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 12 by 13 metres with straight sides. Now it is time to shape the banks.

69. 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.


Dig soil away to shape banks

70. 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.


Inside banks stope leas

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


The top of bank

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

73. The bottom of your pond should be about 1.10 metres from the top of the banks at the shallow upper end and about 1.40 metres from the top of the banks at the deepest part.


the bottom of pond

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

75. 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 to drain out all the water when you empty your pond.


Centre ditch

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


Remove the loose soil

77. Now you are ready to install your inlet, outlet and overflow.