Water Resource

Importance for the Control and Conservation of Water Resources for Agricultural Activities

• USA: Farm products are mainly wheat, maize, grains and beef cattle. ---> They need moderate rainfall (around 500mm).
• India: Farm products is mainly paddy. ---> It needs abundant rainfall (500-700mm).

Water resource is very important for farming. ---> Flooding and drought damage crop products.

Reasons for the occurrence of Flooding

• Abundant rainfall (750-1000mm in USA)
• Occasional storm in rainy season
• Large catchment area of River Mississippi
• Levees are made by earth. ---> It is easily destroyed.
• Land is made of concrete. ---> It increases surface runoff.

Therefore, livestock and crops are lost.

Measures to Control Flooding

1. Construct a dam and reservoir to regular the water flow
2. Build floodwalls or levees
3. Channelization --- deepening and widening the channel
4. Diverting flood water to lakes or streams
5. Soil conservation project --- afforestation, building the wind break and filling the gullies with soil
6. Build or strength dyke
7. Straighten river meanders
8. Construct spillways

Reasons for the occurrence of Drought

• Not enough rainfall (less than 500mm),
• High temperature (excess 45 degree Celsius)
• Evaporation > Precipitation ----> Soil moisture is below the wilting point.

Therefore, lands are not cultivated.

Measures to alleviate Drought

1. Irrigation, e.g. Snowy Mountain Scheme in Australia
2. Decrease intensity of landuses
3. Lengthen the fallow period
4. Plant the drought-resistance crops
5. Reduce cash crop production
6. Build dam to regulate the river flow
7. Open the wall, e.g. artesian wells in Australia
8. Practice dry farming
9. Improve pasture and sheep breeding techniques

By Li Ho Kei