VPE 511: Environment and Environmental Hygiene (2+1)

RAIN WATER

• This is precipitation of water which is obtained as the condensation of moisture in the form of rains, snow and dew.
• The amount of rain water depends upon the rainfall, and the distribution of rain over a period in particular region.
• The two monsoons , the south west and north east monsoons bring about 80 per cent of total rainfall.
• The average rainfall for Tamil Nadu state is about 1143 mm to 1270 mm per annum.
• The rain water must be collected in suitable natural basins or artificial reservoir and stored as a source for use in the farm.
• Rain water at its origin is the least polluted water with minimum impurities but as it descends down it gathers various impurities /pollutants depending upon the activities of the region.
•  Rain water collected under the rural conditions is less polluted than that collected under the urban conditions.
• Rain water collected from highly industrialized places are heavily contaminated with toxic matter or harmful matters.
• In general rain water is comparatively pure and is soft in nature with less of dissolved impurities.
•  It is insipid in taste and some times it will  acidic in reaction, having plumbo solvent characters with corrosive properties.