|Better Farming Series 35 - Better Freshwater Fish Farming: Further Improvement (FAO, 1986, 61 p.)|
|Ways to improve|
|Building even bigger ponds or more ponds|
|A nursery pond|
|Filling and emptying smaller ponds|
|Filling and emptying bigger ponds|
|Bringing water to your ponds|
|Raising the level of your water supply|
|Digging a supply ditch|
|Digging a return ditch|
|Controlling the water in your supply ditch|
|Filling your ponds|
|How to fill your ponds|
|Growing fish all year round|
|Growing only male fish|
|Harvesting your fish|
|Harvesting many fish|
|Harvesting fish when you have a monk|
|Your farm and your fish- ponds|
|Your fish- ponds and your health|
27. If the new ponds that you build are more than 500 square metres (a 20 x 30 metre pond = 600 square metres) it will take much too long to fill them using small pipes. You will need better and faster ways.
A trench inlet
28. You can use a trench inlet just like the one on page 30 in Booklet No. 29 to fill a bigger pond quickly. However, you will also need a screen to keep out wild fish.
29. The drawing below shows you a trench inlet with a corrugated metal bottom and a screen made of woven material.
Use corrugated metal
Another kind of inlet
30. You can also build a kind of gate in the trench to control the flow of water into the pond. This is called a sluice.
31. A sluice has a wall on each side of the trench and a floor set into the bottom of the trench. There are slots in the walls to hold wooden boards or a screen.
32. Boards are put into the slots to keep water out of the pond or taken out to let water in. When you are filling the pond, put in a screen to keep out wild fish.
33. You can build a sluice from wood or if you know how to build with bricks or blocks, you can use these.
34. The drawings below and on the next page show you how to build an inlet sluice using wood.
Building a wooden inlet sluice
Parts of a wooden inlet sluice
Where to put an inlet sluice in the pond bank
Another kind of outlet
35. You can build another kind of outlet to empty a bigger pond faster. It is built inside the bank at the deep end of the pond. This kind of outlet is called a monk. When the pond is filled, the monk will be in the water.
A monk is in the water at the deepest part of the pond
36. A monk is a tall box with two sides, a back, a front formed by wooden boards, and a bottom. Each side has two slots to hold two rows of the wooden boards.
37. Boards are put into the slots to keep water In the pond or taken out to let water out. You will learn more about this on pages 20 to 23 of this booklet.
38. A monk also has a screen like the one shown on page 14. The screen fits on top of the first row of boards and keeps your fish from getting out when the pond is too full or when you are emptying it.
39. A monk also serves as an overflow. So, you will not need to have an overflow pipe like the one shown on page 9 of this booklet.
40. You can build a monk from wood, or if you know how to build with bricks or blocks, you can use these.
41. The drawings on the next pages will show you how to build a monk using wood, and how to fill and empty a pond using a monk.
Where to put a monk in the pond
Parts of a wooden monk
Note: the outlet pipe should be placed at the very bottom of the monk
Where to put a monk in the pond
How to fill a pond when you have a monk
1 put both sets of wooden boards in the slots in the monk and put the screen in place on top of the first row of boards
Fill a pond when have a monk
2 the boards should be as high as the water depth that you want in the pond
3 pack the space between them with good clay soil to keep water from leaking out
Keep water from leaking out
4 let water into the pond
Let water into the pond
5 when the water reaches the top of the boards, stop the flow of water
Stop the flow of water
6 leave the screen in place to act as an overflow if the water becomes too high
Leave the screen
note: you may have to let water into your pond from time to time if the water- level gets too low
How to empty a pond when you have a monk
Empty a pond
1 take out the screen and remove the top board from each slot
Remove the top board
2 the water will begin to flow out and wash away the clay that was between the boards
Wash away the clay
3 quickly put back the screen to keep the fish from getting out
Put back the screen
4 water will flow out until it reaches the level of the next row of boards
Water flow out
5 when this happens, take out the screen again, remove the top row of boards and quickly put back the screen
6 more water will flow out
Water flow out
7 continue to take out boards one row at a time, always putting
back the screen, until the pond is empty
Note: later in this booklet, you will learn how to harvest fish when you have a monk