Ch07

134 If the stream that supplies your water is not much higher than your ponds, it may be difficult to get the water to run down when you want to fill them.

135 By building a barrage, you can raise the level of the stream so

that water will run down more easily into your fish ponds.

Figure 86

136 You can build a simple barrage using a woven mesh of tree branches like the one shown above. You can also use loose stones or rocks or logs set into the stream bottom.

137 A barrage does not hold back all of the water that runs down the stream. Depending on how it is built, some of the water will be held back and some of the water will flow through or over the barrage.

138 If the tree branches, logs or rocks are placed tightly together, the water level behind the barrage will be higher.

139 If the tree branches, logs or rocks are not placed so tightly, the water level behind the barrage will be lower.

140 If you build a barrage and too much water flows through, you can hold back more water by putting more branches, logs or rocks on the barrage.

Figure 87

Digging a supply ditch

141 After you have built a barrage and the water behind it has reached its highest level, you will need to dig a supply ditch to take the water to your ponds.

142 Begin by digging the supply ditch just behind the barrage where the water is deepest. However, dig it in such a way that the water in the stream will not flow into the ditch.

143 You can do this by starting the supply ditch about 1 metre away from the edge of the water. When you are ready to fill your ponds, you can remove this 1 metre strip and the water will flow into the ditch.

144 The ditch should run near the shallow ends of your ponds and in the same direction as the stream that supplies your water.

Figure 88

Figure 89

145 The ditch should have very little slope. You can use a straight board and a mason's level to help you dig your ditch.

146 When you reach your highest pond, the ditch should be near the inlet. Continue to dig your water-supply ditch until you reach your lowest pond.

147 When the supply ditch is past the end of the lowest pond, continue to dig it downhill for about 10 metres

148 Then bring the ditch slowly to the surface. That way, when you fill your ponds, any extra water will flow out at ground level.

149 Now dig a small ditch to connect the inlet of each pond to the supply ditch. Keep its bottom level horizontal.

Figure 90

Digging a return ditch

150 You will also need to dig one or more ditches to take the water back to the stream when you empty your ponds.

151 These are called return ditches. How you dig them will depend on how your ponds are placed and how near they are to the stream. Try to choose the easiest and shortest path to take the water back to the stream.

152 If your ponds are near the stream, the easiest way to get the water back is to dig a return ditch from the outlet of each pond straight to the stream. You can also use one ditch for two ponds.

Figure 91

153 If your ponds are not near the stream or if you cannot dig a ditch straight to the stream, dig only one return ditch along the outlet side of your ponds, which can take all the water from all the ponds.

154 Start this ditch at the outlet of your highest pond. The ditch should run past the outlet of the lowest pond and then back to the stream.

155 Now, dig a small ditch to connect the outlet of each pond to the return ditch.

Figure 92

Building a sluice to control the water flow

156 When you have built your ditches, you will need a way to control the flow of water from the stream into your supply ditch and from your supply ditch into the inlet ditches of each of your ponds.

157 To control the flow of water into your supply ditch, you can build a sluice.

158 This sluice will have three slots in each wall. Two sets of slots are for wooden boards and the third set is for a screen to keep out wild fish.

159 Build this sluice at the top of the supply ditch just behind the 1-metre strip of soil that you left at the edge of the water when you began digging the ditch.

160 The drawing at the top of the next page shows you how to build a wooden sluice for the supply ditch at the stream.

Figure 93

161 Pack the space between the boards with good clay soil to keep the water from leaking through.

162 Do not put in the screen until you are ready to use the sluice. Put it aside so that it will not be broken.

Figure 94 - BUILDING A WOODEN SLUICE FOR THE SUPPLY DITCH

Figure 95

163 Now, remove the 1-metre strip of soil you left at the edge of the stream. The water will flow into the ditch up to the wooden planks in the sluice.

164 Later, when you are ready to fill your ponds, you will control how much water will reach your ponds by removing some planks from the sluice.

165 For better control of the water supply to each pond, you can build smaller sluices in the supply ditch at the lower corners of each inlet ditch, as shown in the drawing.

Figure 96

Figure 97

166 With this sluice you need only one set of boards. The drawing below shows you how.

167 Slide the set of wooden boards into the slot to send ail the water into a pond, or take the boards out to let all the water flow farther down the supply ditch into another pond.

168 You can also adjust the boards in each sluice so that part of the water will go into one pond and the rest will flow down to feed the other ponds.

Figure 98 - BUILDING A WOODEN SLUICE FOR A POND INLET

Summary
YOU HAVE LEARNED HOW TO BRING WATER TO YOUR FISH FARM

Build a barrage to raise the water level of the stream, if necessary

Dig the supply ditch:

dig it in the same direction as the flow of the water supply
bring it along the shallow ends of the ponds
give it very little slope

Dig the return ditch

begin from the deeper ends of the pond
make it as short as possible

Place a sluice at the beginning of the supply ditch

keep it closed with two rows of boards
pack soil between them until you need water on the farm

Place a sluice at the lower corner of each inlet ditch

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