FREQUENCY ANALYSIS OF RAINFALL DEVIATION IN SALEM DT, TAMILNADU 1S.Harikannan,M.E., 2Rizwan.B, 3Rumesh.G, 4Sakthivel.A.S, 5Sakthivel.P 1Assistant Professor, Department of Civil Engineering, Muthayammal Engineering College, Rasipuram-637408. 2,3,4,5Bachelor Of Engineering, Civil Engineering Muthayammal Engineering College, Rasipuram, Anna University: Chennai 600 025 ABSTRACT biological reactions, it happens to be the elixir The aim of this project is to give a complete of life. study of 15 years (2004-2018) daily rainfall The human activities such as rapid data for Salem district was collected from the urbanization, ever increasing population and TWAD (Tamil Nadu Water Supply and deforestation have interrupted the natural Drainage Board) to analyse the nature of hydrological cycle. This ecological imbalance distribution and frequency of rainfall. The results in non-uniform distribution of rainfall. report includes the objectives of the work. The present world has to meet both the Average annual rainfall for 15 challenges of increasing water demand and the years data was collected as 1438.1 mm and depleting water resources. The contamination of average annual rainy days were 65.9 water resources is also increasing in the course maximum monthly rainfall (297.58 mm) was of development and modernization. Hence, a received during the month of September threat to the quantity and quality of this which was mostly by southwest monsoon. valuable resource is emerging at an alarming Maximum rainy days were in October (7.6 rate. days). The present study provides the The rainfall received during the evaluation of groundwater quality during winter, summer, southwest and northeast premonsoon and postmonsoon seasons of the monsoon seasons were 11.5, 191.0, 553.5, study area. It provides the information about the 343.0 mm, respectively. Rainfall frequency concentration of total dissolved solids in analysis done by Weibull’s method revealed groundwater of any location before digging a that the annual average rainfall of 14938.1 well for use. The present study provides a mm can be expected to occur once in 3.5 design methodology for groundwater quality years at a probability of 35%. Monthly improvement using artificial recharge. It also dependable rainfall (p>75%) is expected to provides the information about the recharge occur in every year during the months from potential of the study area. The authorities can September to October. estimate the concentration of major cation and anion of the groundwater present in any INTRODUCTION location before testing the sample. Water is the most precious resource required for Salem is known all over the country for the very existence of living being. It is a its role in poultry and cattle farms. It is also chemical compound and it may either occur in familiar for its automobile industry all over the liquid or solid or gaseous form. All these three southern peninsula. The district has been forms are extremely useful to man in providing divided into 14 administrative blocks and five him the luxuries and comforts in addition to the municipalities by government of Tamilnadu. basic necessities. Water is the renewable natural The area of the district is 3404 sq.km. The resource by the annual replenishment of district has a population of 15 million. The meteoric precipitation. As it is the medium for average rainfall of the district is 670 mm. The most of the chemical, biochemical and ground water table is available below 250 m in ISSN (PRINT): 2393-8374, (ONLINE): 2394-0697, VOLUME-6, ISSUE-3, 2019 472 INTERNATIONAL JOURNAL OF CURRENT ENGINEERING AND SCIENTIFIC RESEARCH (IJCESR) some parts of the district. The total livestock problems than an alternative water supply. Poor strength of the district is 9.07 lakhs and the quality of water adversely affects the plant strength of the poultry is 12.9 million. 10.3 growth also. (Wilcox 1948; Thorne and million eggs are being produced every day in Peterson 1954; US Salinity Laboratory Staff this district and supplied all over the country. 1954; Holden 1971; Todd 2001; WHO 1984; whole district depends on groundwater Hem 1991; Karanth 1997). for drinking, irrigation and industries. 78.12 % The water quality should satisfy the of the total irrigation is carried out with the help requirements or standards set for the specific of groundwater. The district has 81,110 use. The standards specified by Bureau of numbers of open wells and 5,144 numbers of Indian standard specification (IS:10500 1991) is bore wells for public use. The rate of taken in this work to evaluate the quality of groundwater for drinking purpose and USSL, Conceptually, water quality refers to the Wilcox, Doneen classifications are taken to characteristics of a water supply that will evaluate the quality of the groundwater for influence its suitability for a specific use i.e., irrigation purpose of the study area. how well the quality meets the needs of the user. Even a personal preference such as taste is REVIEW OF LITERATURE a simple evaluation of acceptability. For 2.1 LITERATURE REVIEW example, if two drinking waters of equally good Ramasamyet al(1999) have quality are available, people may express a analysed the monthly and annual rainfall data of preference for one supply rather than the other; Coimbatore district for the period from 1971-72 the better tasting water becomes the preferred to 1993-94. This analysis shows that the rainfall supply. is just normal and below from 1980-81 to 1993- The quality of water is a vital factor for 94. Hence the rainfall of this nature might not mankind as it is directly linked with human contribute to augment groundwater potential. health. The quality of groundwater is being In the same way, Singh et al(2004) modified when it is in the course of movement have made an attempt to understand the through the hydrological cycle and through the performance of monthly rainfall for June, July, various processes such as evaporation, August and September when the seasonal transpiration, uptake by vegetation, rainfall is reported to be excess, deficient or oxidation/reduction, cation exchange, normal by using historical data series of 30 dissociation of minerals, precipitation of years (1970-99) of monthly and seasonal secondary minerals, mixing of waters, leaching rainfall. All the locations receive excess or of fertilizers, manure and pollution (Appelo and normal rainfall in monsoon season when Postma 1993). individual month receives excess rainfall in the Presence of certain minerals such as iron, entire subdivision. From the probability calcium, magnesium etc., in small quantities in analysis, it is seen that there is a rare possibility groundwater may be good for health, because of occurrence of seasonal rainfall to be human bodies need certain amount of these excess/deficient when the monthly rainfall of elements as nourishments. But when these any month is deficient/excess in the entire materials and others are dissolved in large subdivision. amounts, the water may become unfit for Prediction of groundwater levels has consumption. Some times the water may significant applications in water resource contain toxic or poisonous substances such as utilization and management. The purpose of arsenic, cadmium etc. These substances are observation of groundwater lies primarily in harmful to the health even if it is present in very studying its temporal and spatial changes. low quantities. Statistical approaches are becoming In irrigation water quality evaluation, emphases increasingly useful for the evaluation of are placed on the chemical and physical groundwater regimes. Rockaway &Johnson characteristics of the water. Other factors are (1977) have indicated that the application of considered as important in special applications. trend analysis to groundwater studies is based Specific uses have different quality needs and on the assumption that the water table could be one water supply is considered more acceptable approximated by a mathematically computed if it produces better results and causes fewer ISSN (PRINT): 2393-8374, (ONLINE): 2394-0697, VOLUME-6, ISSUE-3, 2019 473 INTERNATIONAL JOURNAL OF CURRENT ENGINEERING AND SCIENTIFIC RESEARCH (IJCESR) polynomial of water levels of the wells in the Similarly, Jayakumar & Ramasamy aquifer. (1995) have conducted a study on groundwater Marechalet al(2002) have observed in the Attur village of Salem district in Tamil the short-interval water levels in a deep well in Nadu. Fifty wells are identified and their well an unconfined crystalline rock aquifer. The yield data are derived from pumping tests. observed values show cyclic fluctuation in the Rainfall data of 35 years are collected and water levels and principal trend due to rainfall extrapolated to 50 well locations by kriging recharge. Spectral analysis is carried out to method. The well yield data are taken as the evaluate the correlation of the cyclic fluctuation dependent variable and rainfall data are taken as to the synthetic earth tides as well as the independent variable and bivariate and third groundwater withdrawal time series in the degree polynomial regression analyses are surrounding area. It is found that the carried out. From such analyses, a model is fluctuations have considerably high correlation developed, which is capable of predicting well with earth tides, whereas groundwater pumping yield from rainfall data. The predicted and does not show any significant correlation with observed yields are compared. The variations water table fluctuations. It is concluded that the are restricted within 20% of the original values; earth tides cause fluctuations in the water table hence the model could be accepted. and unconfined aquifer is characterized by a The monsoon rain recharges mainly low porosity. hard rock aquifers in the rain-fed areas of India. The conventional method of The water table is at its lowest level in the estimating recharges is used by Penman (1948) beginning of the monsoon (May-June),it rises as and Grindley(1967).