|Better Farming Series 28 - Water: Where Water Comes from (FAO, 1981, 31 p.)|
|Water on the surface|
86. Water on the surface of the ground comes from both groundwater and from surface water run- off.
Water on the surface
87. When it rains, water sinks into the ground and mixes with the water already in the ground.
88. When there is more water in the ground, the water table becomes higher.
89. If the land is low and the water table is high enough, it may lie above the surface of the ground. Then there is more surface water.
Water lies above the surve of the ground
90. When it does not rain, there is less water in the ground and the water table becomes lower.
There is less water in the ground
91. Then there will be less surface water. This can be seen in dry times in swamps, lakes and streams.
92. The effect of groundwater on surface water is hard to see for it happens very slowly.
The effect is hard to see
93. When it rains, water which does not sink into the ground runs over the surface into low land.
94. When there is very much rain, more water runs over the surface and low land quickly fills with water. This can be seen during wet seasons in swamps, lakes and streams.
95. The effect of run- off on surface water is easy to see for it happens very quickly.
The effect is easy to see