Water

1. Water part 1 V.Lokeesan , BSN T.Assistant lecturer FHCS,EUSL.

2. Objectives Water Sources and characteristics Purpose of water, types of wells

3. Introduction Health care to a community cannot be provided without ample and safe drinking water Health which affects humanity especially in developing countries is due to lack of safe and wholesome water Water that is easily accessible, adequate in quantity, should be free from contamination, safe and readily available throughout the year.

4. Safe and wholesome water Free from pathogenic agents Free from harmful chemical substances. Pleasant to taste i.e., free from colour and odour and Usable for domestic purposes Water is said to be polluted or contaminated when it does not fulfill the above criteria.

5. Water requirement The basic physiological requirements for drinking water has been estimated at about 2 liters per head per day. A daily supply of 150 – 200 liters per capita is considered as an adequate supply to meet the needs for all urban domestic purposes. Water should be made available in adequate volume to reduce the incidence of water related diseases.

6. Uses of water The uses of water include: Domestic use : Drinking, cooking, washing, bathing, flushing of toilets, gardening etc. Public Purposes : Cleaning streets, purposes like swimming pools, public fountains, ornamental ponds, fire protect and public parks. Industrial Purpose : Processing and Cooling. Agriculture Purpose : Irrigation Power Production : from hydropower and steam power Carrying of waste : through drainage.

7. Sources of water supply There are three main sources of water 1. Rain water 2. Surface water Impounding reservoir Rivers and streams Tanks, ponds and takes 3. Ground water Shallow wells Deep wells Springs

8. Rain water Rain is the prime source of all water. Rain water is the purest in nature: Physically - it is clear, bright and sparkling. Chemically - it is very soft containing traces of dissolved solids. Bacteriologicaly – it is clean and free from pathogenic agents. The amount of rain water collected will depend upon the rainfall. 1 cm of rainfall over, 1 sq.m will yield 10 liters of water. Rain water needs to boiled or disinfected if used for drinking.

9. WATER CYCLE

10. Surface water Surface water originates from rain water. It is the main source of water supply in many areas. Examples of surface water include rivers, tanks, lakes, man – made reservoirs and sea water. Surface water is prone to contamination from human and animal sources. Surface water needs purification before use for drinking and cooking purposes.

11. Impounding reservoirs These are artificial lakes constructed usually of earthwork or masonry in which large quantities of surface water is stored. Dams built across rivers and mountain streams also provide large reserves of surface water. The area draining into the reservoir is called “catchment area”. The disadvantage of storing water is the growth of algae and other microscopic organisms, which impart bad tastes and odors to water.

12. IMPOUNDING RESERVOIRS [cont...] Characteristics Impounding reservoirs usually furnish a fairly good quality of water. The water is usually clear, palatable and ranks next to rain water in purity. The water is usually soft and considered tobe free of pathogenic organisms. Impurities The upland surface water derives its impurities from the catchment area, the sources being human habitations and animal keepig or grazing.

13. Rivers Characteristics River water is turbid during rainy season; it may be clear in other seasons. Clarity of water is no guarantee that river waer is safe for drinking. It contains dissolved and suspended impurities of all kinds. Impurities The impurities of river water are derived from surface washings, sewage and sullage water, industrial and trade wastes, and drainage from agricultural areas.

14. Tanks Tanks are large excavations in which surface water is stored. They are an important source of water supply in some parts of the country. Tanks are recipients of contamination of all sorts. They are full of silt and colloidal matter, especially after the rains. Older tanks may be full of aquatic vegetation.

15. Ground water Rain water percolating into ground water constitutes ground water. Ground water is the cheapest and most practical means of providing water to small communities. Ground water is superior to surface water, because the ground itself provides an effective filtering medium.

16. Ground water [cont...] ADVANTAGES DISADVANTAGES It is likely to be free from pathogenic agents It is usually requires no treatment The supply is likely to be certain even during dry season It is less subject to contamination than surface water. It is high in mineral content . It requires pumping or some arrangement to lift the water.

17. Wells Traditionally wells are the common and main source of water supply in most areas. Technically wells are of two; Shallow wells- tap subsoil water Deep wells- taps water from the water bearing stratum

18. Shallow well Deep well Definition Taps the water from above the first impervious layer Taps the water from below the first impervious layer Chemical quality Water is moderately hard Much harder Bacteriological quality Often grossly contaminated pure water Yield Dry in summer Constant supply

19. Classified according to method of construction Dug wells Tube wells

20. Sanitary well This is a well that is properly located, suitably constructed and well protected from contamination, thus supplying safe water. The following important points are to be taken into consideration in constructing safe wells: Location Lining Parapet Platform Drain Covering Hand-pump

21. Sanitary well [cont…] Location Should be away not less than 15m from sources of contamination Distant between well and the house (<100m) Lining Lining should be built of bricks or stones set in cement up to 6 m deep, to allow the water to enter from the bottom and not from the sides of the well. Lining should be curried 60-90cm above the ground

22. Sanitary well [cont…] Parapet wall A parapet wall around the well up to the height of at least (70-75 cm) should be provided above the ground. Platform Along with the parapet wall the platform should be made with cement concrete extending at least 1m in all directions. It should have gentle slope outward leading to a drain built along its edges.

23. Sanitary well [ cont…] Drain A pucca drain should be built to collect the spilt and dirty water from the platform of the well and this should be channeled to a drain or soak pit that is away from the well. Covering The top of the well should be covered well by a cement concrete cover to avoid direct contamination.

24. Sanitary well [ cont…] Hand-pump A good sanitary well should be equipped with a hand pump to lift the water in a clean manner. When such a facility is not available, it is desirable to attach a chain and a bucket to the well for the common use.

25. Springs Ground water comes to the surface and flows freely under natural pressure Two types Shallow springs Deep springs

26. REFERENCES Park,K .(2010). “ Park’s Textbook of Preventive and Social Medicine”. Ed 20. Bhanarsidoss Bhanot Publishers, Jabalpur , India. Rao , K.S. (2004). “An Introduction to Community Health Nursing”. Ed 4. B.I. Publications Pvt. Ltd, Chennai, India.