Measurement of Spatial Variation of Rainfall in Cuddalore District Using Ilwis
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International Journal of Innovative Technology and Exploring Engineering (IJITEE) ISSN: 2278-3075, Volume-8, Issue-6S4, April 2019 Measurement of Spatial Variation of Rainfall in Cuddalore District using Ilwis S.Sivaprakasam, K.Karthikeyan, N.Nagarajan, Visalachi Abstract—Rainfall is a one of the important phenomena of the (AlakGadgil - 1986). Hydrologists require timescale, hydrological cycle; its distribution time to time, varies from one detailed knowledge of the frequency, volume and spatial place to another place; and it acts as a source of water to the distribution of the precipitation to assess the local imparts of earth. Indian agriculture and the cropping pattern, with good impending extreme weather events to adapt to climate yield of production, depend on the rainfall during monsoon. According to the IMD, South peninsular region got 40% of change (Fowler et.al. 2007). The annual and seasonal rainfall from South-West monsoon and 60% from North-East rainfall along with its variability has been analyzed for monsoon. This study aims at understanding the spatial Cuddalore District, Tamilnadu, busing the QGIS software distribution of rainfall and its influences in the hydrological (Sandeep, et. al 2018). The current study focuses attention trend of precipitation over the area which is closely linked with on the spatial distribution of the rainfall, coefficient of flood and drought. For the purpose of evaluation, the rainfall variability and precipitation ratio. data of 21 stations were collected from statistical department and PWD Ground water division of Cuddalore district during period of 1986 – 2016. After error correction and checking, the general 2. STUDY AREA methodology was applied for this study. The collected data and Cuddalore district is located at the geographical the real time data were matched for the mathematical analysis to coordinates of 11° 11" to 12° 35" N latitude, 78° 38" to 80° find the Mean, Seasonal variation, Coefficient of Variation, Precipitation Ratio. The spatial distribution of rainfall convert as 0" E longitude and altitude is 4.6m MSL. The study area is the non spatial data of an attribuutive information in the form of the Eastern part of Tamilnadu and is surrounded by statistics, tabled list, graphs and finally, using the ILWIS Villupuram, Nagapattinam and Perambalur on North, South software, to find the influence of rainfall over the area were and West respectively and on East by Bay of Bengal as identified and demarcated with maps. The long term rainfall shown in figure 1. The total area is about 36.78 sq. km. The analysis identifies the influence and pattern of spatial average temperature ranges from 24.4 °C during January to distribution of Cuddalore district. maximum of 32 °C during June. The coastal region of the Key words:—Rainfall, Monsoon, Spatial distribution, Hydrological trend. study area like Parangipettai, Chidambaram, Bhuvanagiri have an altitude of 5-6 m above the MSL. The central 1. INTRODUCTION regions of the study area have an altitude of 9-10 m above MSL. The minimum altitude is observed in the South and it Universally, water is the main commodity playing major is found ascending as it moves towards the north. The role in world economy. The main source of fresh water is western regions of the study area have an altitude of about rainfall. According to NASA, the most obvious pattern, in 45m above the MSL. the total rainfall maps, is the change in seasons. A band of heavy rain moves North and South of the Equator seasonally. About two-thirds of all rain falls along or near the equator. Rainfall is an important phenomena in the hydrological cycle. It plays a major role in planning of water resource projects, agriculture and other related domains. Tamilnadu is a tropical State in India. Its climate varies from dry sub humid to semi arid. The pattern of rainfall is not a constant as it varies from time to time and place to place. The variability of rainfall alters the cropping pattern. Rainfall is an agro-climatological factor that prevails in the seasonally arid parts of the world and its analysis is an important prerequisite for agricultural planning in India Revised Manuscript Received on April 12, 2019. S.Sivaprakasam,Assistant Professor, Department of Civil Figure1 Map of Cuddalore district Engineering, Faculty of Engineering and Technology, Annamalai University, Annamalai Nagar, Tamilnadu, India. ([email protected]) K.Karthikeyan,Assistant Professor, Department of Civil Engineering, Faculty of Engineering and Technology, Annamalai University, Annamalai Nagar, Tamilnadu, India. N.Nagarajan,Assistant Professor, Department of Civil Engineering, Faculty of Engineering and Technology, Annamalai University, Annamalai Nagar, Tamilnadu, India. Visalachi, PG student, Department of Civil Engineering, Faculty of Engineering and Technology, Annamalai University, Annamalai Nagar, Tamilnadu, India. Published By: Blue Eyes Intelligence Engineering Retrieval Number: F10060486S419/19©BEIESP 29 & Sciences Publication DOI: 10.35940/ijitee.F1006.0486S419 Measurement Of Spatial Variation Of Rainfall In Cuddalore District Using Ilwis OBJECTIVES Variability is expressed as the ratio of the standard deviation To determine the Coefficient of variation and to the mean rainfall. Precipitation Ratio. CV in % = To plot the Spatial distribution map with the help of Standard Deviation ILWIS. x 100 To locate and demarcate the abnormality of rainfall Mean Rainfall area. Precipitation Ratio Precipitation Ratio resembles the abnormality of rainfall 3. METHODOLGY in the area. The higher value represents the higher abnormality, while the lower values show the lower abnormality. Precipitation Ratio is expressed as the ratio of difference between the maximum and minimum rainfall to the mean rainfall. PR in % = [( Pmax - Pmin ) / Pmean] x 100 Where, Pmax = Maximum Rainfall in mm Pmin = Minimum Rainfall in mm Pmean = Mean Rainfall in mm Table 2 Annual Mean and Seasonal Rainfall East East West West - Station Name - Winter rainfall Summer Monsoon Monsoon North South Annual mean mean Annual Annamalainagar 61.7 110.2 318.4 990.6 1480.9 Bhuvanagiri 47.2 72.3 221.6 747.4 1088.5 Chidambaram 63.3 105.5 294.1 949.7 1412.6 Figure 2 Flowchart showing methodology Cuddalore 47.3 89.0 339.1 855.1 1330.4 Kattumailur 12.3 85.4 296.5 554.1 948.3 This study has taken 21 rainfall stations and collected a data for 30 consecutive years’ from the PWD during the Kattumannarkoil 42.5 120.7 360.9 847.1 1371.2 period of 1986 – 2016. The annual and seasonal variations Kilcheruvai 18.9 125.0 484.4 678.9 1307.3 of rainfall such as summer, winter, North-East Monsoon and Kothuvacheri 35.2 83.2 254.7 751.2 1124.3 South-West Monsoon are analyzed as shown in table1. The Kuppanatham 27.3 113.3 381.3 611.8 1133.8 Coefficient of Variability and Precipitation Ratio for all the Lekkur 11.1 118.9 387.0 537.5 1054.6 stations, in the study area, have been found and the plot Memathur 22.7 96.9 345.5 698.9 1163.9 spatial distribution map has been drawn with the help of Palur 49.1 103.5 284.4 796.9 1293.2 ILWIS. The ILWIS is a Geographical Information System Panruti 24.6 77.1 298.6 721.1 1121.5 Software. It was initially developed by researchers in Parangipettai 54.0 80.5 284.4 951.2 1370.0 Netherlands. The collected data and maps have been Pilandurai 23.7 136.1 382.5 645.2 1187.5 processed using ILWIS. It has been analyzed and Sethiathopeanicut 46.3 100.2 359.3 807.7 1313.5 interpolated by the method of Kriging in the ILWIS Srimushnam 40.9 90.0 387.3 762.2 1280.4 software as shown in figure 2. Vanamadevi. 37.0 65.4 283.8 655.9 1042.2 Tholudur 14.1 142.8 439.5 652.9 1249.2 Table 1 Various Seasons of Rainfall Veppur 7.2 81.3 253.3 484.0 825.9 SEASON MONTH Virudhachalamtal 24.9 123.6 375.1 581.7 1105.3 Winter January – February uk office Summer March – May Mean 33.9 101.0 334.8 727.7 1200.2 South-West Monsoon June – September North-East Monsoon October - December Variability of Rainfall The Rainfall Variability is the value to express the dependability of rainfall. The lower variability of percentage represents the higher dependability and vice versa. Rainfall Published By: Blue Eyes Intelligence Engineering Retrieval Number: F10060486S419/19©BEIESP 30 & Sciences Publication DOI: 10.35940/ijitee.F1006.0486S419 International Journal of Innovative Technology and Exploring Engineering (IJITEE) ISSN: 2278-3075, Volume-8, Issue-6S4, April 2019 Figure 3 Spatial map of annual mean rainfall Figure 8 Spatial map of north-east monsoon mean rainfall 4. RESULT AND DISCUSSION Annual Mean Rainfall The average monthly rainfall, for the 21 stations under study for a span of 30 years, shows an increasing trend from January to December as shown in figure 4. It reaches the Figure 4 Monthly variation of Rainfall Pattern peak during North East Monsoon. The minimum mean is incurred as 825.9 mm at Veppur and Maximum as 1480.9 mm at Annamalai Nagar. The annual mean rainfall of all stations is 1200.2 mm as shown in figure 3 and table 2. The results show the point that all the stations, except Kattumailur and Veppur, experience the high rainfall of more than 1000 mm. The very high rainfall zones (>1300 mm) include Annamalai Nagar, Chidambaram, Kattumannarkoil, Cuddalore, SethiayathopeAnicut, Kilcheruvai and Parangipettai. The high rainfall zones (1200 - 1299 mm) include Srimushnam, Tholudur and Palur. The moderate rainfall zones (1100 - 1199 mm) are Memathur, Figure 5 Spatial map of winter mean rainfall Kuppanatham, Kothavacheri, Panruti, Pilandurai and Virudhachalamtaluk office. The low rainfall zones (1000 - 1099 mm) are Bhuvanagiri, Lekkur and Vanamadevi.