1 what is the source of ...

1 what is the source of water? if from a small stream the elevation of the water in the pond cannot be higher than the surface of the water in the stream.

2 the bottom of the pond the outlet must be higher .than the fields to be irrigated.

3 a topographic map showing the irrigated area, the pond site and the source of water is necessary

4 you should know how much water is needed per day for each crop, how often to irrigate and how much evaporation there will be from the pond

5Example: storage per hectare of pond

 a) what is the evaporation average per day? 6m"m which is 60 cubic meter per hectare

for a growing season of 100 days you need 100 x 60 =6000 cubic meters of water. to reduce evaporation the smaller the surface area the less evaporation. The temperature and moisture of the air affect evaporation.

The sides of the pond should have a slope of 2.5 meters for each meter of depth. A 4 meter depth will need 10 meter width . The pond must have anextra 0.5 -1.0 meter depth to prevent overtopping caused by winds.

 The earth excavated for the pond storage should be used as embankment around the pond.