RAINFALL VARIATION AND FREQUENCY ANALYSIS STUDY IN NAMAKKAL DISTRIC TAMILNADU 1Prof.V. Rajendran,M.E.,(Ph.D) 2Nanthini. A, 3Padmakumar. G, 4Thopic Ahamed. K, 5Vijayvarman. J 1Head of the Department, Department of Civil Engineering, Muthayammal Engineering College, Rasipuram, Namakkal. 2,3,4,5Bachelor Of Engineering, Civil Engineering Muthayammal Engineering College, Rasipuram -637408, Anna University: Chennai 600 025 ABSTRACT rainfall data used for this analysis is from The aim of this project is to give a complete 2004 – 2018. In this analysis rainfall study of Ten years (2009-2018) daily rainfall variability has been calculated to find out the data for Namakkal district was collected dependability of rainfall over the study area. from the TWAD (Tamil Nadu Water Supply From the analysis it is to be identified that and Drainage Board) to analyse the nature of Paramathy location has more than 50% of distribution and frequency of rainfall. The CV in both the monsoon season. To report includes the objectives of the work. understand the long term changes in rainfall Average annual rainfall for 10 years data trend analysis has also been studied over the was collected as 938.1 mm and average area. It is a powerful tool for representation annual rainy days were 45.9 maximum and analysis of spatial information related to monthly rainfall (197.58 mm) was received rainfall analysis. during the month of September which was Keywords: Climate, Variability, Monsoon, mostly by southwest monsoon. Maximum Trend. rainy days were in October (8.6 days). The INTRODUTION rainfall received during the winter, summer, 1.1 GENERAL southwest and northeast monsoon seasons Rainfall, being considered as the prime were 10.5, 181.0, 453.5, 293.0 mm, input for agriculture has its own erratic behavior respectively. Rainfall frequency analysis in terms of amount and distribution. For better done by Weibull’s method revealed that the crop planning, a detailed study on rainfall annual average rainfall of 938.1 mm can be behavior is vital. Rainfall variability, both in expected to occur once in 2.5 years at a time and space influences the agricultural probability of 40%. Monthly dependable productivity and sustainability of a region. rainfall (p>75%) is expected to occur in Rainfall analysis for crop planning was carried every year during the months from out in different regions of the country as September to October. Climatic factor plays reported. The annual and seasonal rainfall a major role in Indian agriculture in that received and its variability directly influences rainfall play a key role. Being rainfall is the the success or failure of crops through its important factor for agriculture normally beneficial or adverse effect their growth and has to rely on secondary data. The study area yield. Therefore, the study of variability of taken for this analysis is Namakkal district of annual and seasonal rainfall is essential in Tamil Nadu The extent of the area is extends selection of suitable crops and to take between 11º00’ to 11º36’10” north Latitudes appropriate mitigating measures based on and 77º40’ to 78º30’00” east longitudes. It is rainfall characteristics. Agriculture being purely a semi arid region and agriculture mainly rainfed in Namakkal region of Tamil normally depends on seasonal characteristics Nadu state is characterized by uneven and of rainfall. This study seeks to understand erratic distribution of rainfall. Since rainfall is the rainfall behavior of the study area. The the only source of moisture, the spatio-temporal ISSN (PRINT): 2393-8374, (ONLINE): 2394-0697, VOLUME-6, ISSUE-3, 2019 495 INTERNATIONAL JOURNAL OF CURRENT ENGINEERING AND SCIENTIFIC RESEARCH (IJCESR) distribution of rains holds the key in Rasipuram and Namakkal on the East and determining the fate of entire crop productivity Salem, Omalur and Mettur on the West. The in the region. There are so many authors studied Kolli hills in Namakkal and few isolated hills about the rainfall variability, Krishnakumar and and ridges scattered over Namakkal, Rasipuram Prasad Rao (2008) reported rainfall variability and Tiruchengode along with the Valleys and in Gujarat and Kerala state respectively. rolling topography contributes to the beautiful Halikatti et al. (2010) reported annual and physiography of the Namakkal district. seasonal rainfall variability at Dharwad, The northern regions of the district of Karnataka. A similar attempt was made to Namakkal are mountains and the southern areas analyze the rainfall distribution pattern in are plains. The plain area of this district can be monthly, seasonally and annually for Raichur divided into three elevating stages. The lower region. elevation (which is below one hundred and fifty The district is divided into two Revenue meters) has Namakkal and Paramathytaluks Divisions: Namakkal and Thiruchengode, with which are benefited by the Kaveri River. The five Taluks earlier namely Namakkal, mid-elevation (which is from one hundred fifty Thiruchengode, Rasipuram, Paramathi and to three hundred meters above the mean sea Kollihills. Sendamangalamhas been announced level) occupies the major area in all taluks. The as a new Taluk with 30 Revenue firkas. The high elevation area (which is between three district has five Municipalities, 15 Panchayat hundred to six hundred meters) spreads over Unions (Blocks), 19 Town Panchayats and 322 mainly in Rasipuram and Namakkaltaluks. The Village Panchayats. The Northern portion of major rivers running through the Namakkal Namakkal is mountainous and the southern district in Tamil Nadu are Cauveri, areas are plains. The chief rivers that run Karipottamaru and Thirumanimuthar. Soil through the district are Cauvery, Aiyaru, Condition The soil of Namakkal district can be KaripottanAaru and Thirumanimutharu. The broadly classified into 5 major soils types viz., river Cauvery flows south and south west Red Soil, Black Soil, Brown soil, Alluvial and traversing across the border. It is one of the Mixed Soil. Major part of the district covered major water sources for over all socio economic by Red Soil. Black soils are mostly seen in progress of the district. Geography Namakkaltaluk. Brown Soil occupies only a Namakkal District comes under the small portion of Tiruchengodetaluk and the north western agro climatic zone of Tamil Alluvial Soil is seen along the river courses in Nadu. It was bifurcated from Salem District and Namakkal, Paramathi and Tiruchengodetaluks. has been functioning as a separate district since Mixed soil is the second major soil type 01-01-1997. occurring all the taluks of the districts. It is bounded by Salem in the Climate.The district enjoys a tropical climate. north,Karur in the south,Trichy in the east and The weather is pleasant during the period from Erode in the west. The Geographical area of the November to January. The normal rain fall district is 3363.35 square km. Geography of the occurs during North East monsoon and district is vast and it possesses several hilly moderate rainfall is received during South West regions. The district is situated at an altitude of monsoon. Human Development Status.HDI three hundred meters above the MSL (mean sea Blockwise indicates the top three ranks holding level). The Kumarapalayam channel runs for blocks as ThiruchengodeNamakkaland 10.7 km covering the land area of 1032.59 Rasipuram. Kollihills block has been placed in hectares. Thirumanimutharu River starts from the lowest position of three indices.. Literacy Salem district up to Namakkal for the coverage rate is very low compared to other blocks. Most of total area of 18,621 hectares by 105km long of the people are marginal farmers engaged in length of distance. It benefits the lands in agriculture activities only. The basic amenities Namakkal district by 34.44 per cent only. The are very poor particularly, facilities of fuel, Karattaru begins at Kollihills runs up to Trichy toilet, house and electricity. In terms of health district covering a distance of 41km and aspect, the IMR, MMR and U5MR was also irrigating 8318.05 hectares. Topography poor. Pallipalayam block is placed first for It is placed in the dividing portion of having lowest gender inequality in the district. two watersheds between the Kaveri and the This block is covered by the strong mixture of Vellar System with the taluks of Attur, industry and agriculture situated on the bank of ISSN (PRINT): 2393-8374, (ONLINE): 2394-0697, VOLUME-6, ISSUE-3, 2019 496 INTERNATIONAL JOURNAL OF CURRENT ENGINEERING AND SCIENTIFIC RESEARCH (IJCESR) Cauvery and very near to the adjoining district observation of groundwater lies primarily in of Erode. Erumapatty block is placed in the studying its temporal and spatial changes. second position of top three due to high female Statistical approaches are becoming literacy rate and as female participation. increasingly useful for the evaluation of In the electoral roll was found to be very groundwater regimes. Rockaway &Johnson high at the same time and the agricultural wage (1977) have indicated that the application of rate did not have any huge variation. trend analysis to groundwater studies is based Mallasamuthiram was placed in a lower rank in on the assumption that the water table could be GII due to MMR being high, low level of approximated by a mathematically computed literacy, low female participation in polynomial of water levels of the wells in the empowerment and work participation in non- aquifer. Agriculture and vast variation in agricultural Marechaletal(2002) have observed wage rate. In CDI, the top level blocks – the short-interval water levels in a deep well in Pallipalayam, Mohanur and Tiruchengode fared an unconfined crystalline rock aquifer. The well in the dimensions of health and education. observed values show cyclic fluctuation in the At the sametime, in the bottom level, blocks water levels and principal trend due to rainfall other than Kollihills, (except U5MR) all other recharge. Spectral analysis is carried out to indicators of health and education were found to evaluate the correlation of the cyclic fluctuation be enhanced in Vennandur and Puduchathiram to the synthetic earth tides as well as except U5MR.