Wednesday, April 6, 2011

Soil zonation

A portion of the water entering the ground will get trapped by rock, soil, and so on, and remain in the upper soil zone as suspended water. Suspended water has been disallowed from moving deeper into the soil by the molecular attraction that are exerted on the water by the surrounding soil particles, as well as by the inter-molecular attractions exerted by the water molecules on each other. As the spaces between the soils particles in this zone have been filed with a mixture of air and water, this portion of the soil has been known as the zone of aeration and has been subdivided into three distinct horizons: the horizon of soil moisture, the intermediate horizon and the capillary fringe. A portion of the water that enters the horizon of soil moisture could be either evaporated or transpired. The remainder would be passing into the intermediate horizon, where it tends to be held as suspended water by molecular attractions. There occurs little water movement in the intermediate horizon, except during periods of precipitation, when additional incoming water enters the horizon. In some areas the intermediate horizon has been absent, and the horizon of soil moisture lies directly over the third horizon, the capillary fringe.
Water quality: Supplies have to be drawn from the best available source. When the source cannot be protected against pollution the water has to be treated to ensure its safety.
Physical characteristics of water: 
1.      Turbidity: Turbidity should average not more than 1 unit, although and Jackson turbidity unit of 5 has been acceptable. At levels approaching 10 units the water may appear cloudy to the observer. 
2.      Color: Color must average not more than 5 units. Color does not take place too frequently in the natural waters. Leaching effect of the water on organic material found in certain watersheds may range beyond 50 units.
3.      Temperature: Temperature has been a physical characteristics about which little can be done. The most desiarable range has been from 40-50F.Higher temperatures tend to make water less patable and decrease its sustability for air conditioning purpose.
Chemical characteristics:
1.      Limits for chemical constituents: The chemical constituent concentrations in water could be broken down into two categories: those concentrations that can be tolerated if another, more suitable source has been not available.  
2.      Taste and color: Taste and odor have been very closely related and have been caused by the sane conditions. Common sources of taste and odor have been as follows:

  • Dead or decaying organic matter
  • Living organisms and oils from algae 
  • Industrial wastes
  • Dissolved gases
  • Dissolved minerals.

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