Hard water is generally considered to be one which requires considerable amount of soap to produce foam or leather. Hard water cause scale formation in boilers heaters and hot water pipes. The rain water catches CO2 from the atmosphere when the water pass through CaCO3 rock in the Soil, these compounds make the water hard. Calcium and magnesium chlorides

The total dissolved solids mainly consist of the test that acts as a check on detailed analysis. Another useful aspect is that electric conductivity can be continuously recorded. Any sudden change indicate a change of water. A treatment method can be there fore instantly detected. Determination of total solids is used in two operations. In developing a potential source

Alkalinity is an important determination to the water treatment plant operator because some of the coagulants used to clarify water and prepare it for filtration required sufficient alkalinity to insure a proper reaction. The alkalinity may be increased by adding lime or NA2CO3. Excessive alkalinity may be however interfere with coagulants.

The structure used to retain or support the material/soil is called retaining structure. e,g retaining walls, which may be of RCC, brick or stone masonry or sheet piling etc.

It is strong in compression and weak in tension so no tension should be allowed in any part of the retaining wall, especially the base of the supporting wall. Earth embankments/slopes are commonly required on railways, roads, earth dams etc. The stability of these slopes must therefore be thoroughly analysed as their failure may lead to loss of human life as well as economic