Volume : 2 | Issue : 4 | April 2013 • ISSN No 2277 - 8160 Research Paper Engineering A Study of Groundwater Fluctuation in Coastal Region, Valsad and Navsari District. Aarti Avalkar Research Scholar, M. E Civil (W.R.M) , Government Engineering College, Surat Dr. S. M. Yadav Prof. Civil Engineering Department, SVNIT, Surat Sahita Waikhom Asso. Prof. Civil Engineering Department, Government Engineering Col- lege, Surat. Dr. P. R. Mehta Retired Principal, SVNIT, Surat ABSTRACT The objective of this paper is to study the groundwater seasonal and annual fluctuation and trend of groundwater level and its effect on groundwater level due to rainfall in coastal region Valsad and Navsari District of Gujarat State. Water level data of last 20 years of 100 wells were collected. The yearly and as per distance from sea variation of average groundwater level fluctuation is shown in graph for premonsoon, postmonsoon and annual, also groundwater level vs rainfall vs graph are draw to study their co-relation. The result shows that groundwater level shows a seasonal pattern of fluctuation. The variation of decadal average water level trend is increasing and average water level with the distance from sea shore is decreasing for Valsad district. The variation of decadal average water level trend is decreasing and average water level with the distance from sea shore is decreasing for Navsari district. When co- relating average annual water level with average annual rainfall the water level is increasing with rainfall. When co-relating it with good rainfall year, the water level is high compare to good rainfall year for both districts. KEYWORDS: Water table, Ground water, Fluctuation, Seasonal variations, coastal area. I. INTRODUCTION pography. Variation in rainfall is reflecting in the full saturation of Valsad and Navsari district is located at the southernmost tip of the aquifer in high and assured rainfall zone and partial saturation Gujarat, near Gulf of Khambhat in the Arabian Sea. Water resourc- in the low rainfall zone/drought prone area. Patterns of rise and es in any part of the world are subject to change due to mete- fall of water levels is directly related to the intensity, amount and orological and climatologically impact all the year long. Impact duration of rainfall, seasonal fluctuation and water abstraction for of these factors on water resources has been extensively studied. different causes as there exists a variable time lag between two (Chen 2002). Groundwater is the primary source of water for hu- rainfall sessions or due to vagaries of monsoon. (Bhagyashri C. man activities such as agriculture, industry and domestic drink- Maggirwar1 2011). The long term historical and meteorological ing water especially in regions with limited annual precipitation data ,among all, temperature and rainfall can be used to assess (Todd, 1980). Ground water, the rest portion of water during per- the future surface water, ground water table and storage varia- colating into the soil and after meeting the necessary soil mois- tions in order to have a better insight into the problem posed in ture deficiency, occurs at various locations below the earth’s sur- the future.( Mohamad Aflatooni1* and Mehdi Mardaneh2 2011). face depending on the physical properties of various formations that exist. Such as aquifer, unconfined aquifer, confined aquifer II. STUDY AREA aquiclude, aquitard, aquifuge etc. Groundwater which is used for The study area of my work is Valsad District and Navsari District domestic and industrial water supply and irrigation is vital to lo- cal people and industry in semi-arid and arid areas like Valsad and 1) VALSAD DISTRICT:- Navsari District where groundwater is the main drinking water Valsad district is located at the southernmost tip of Gujarat, near Gulf source. In the last few decades, tremendous increase in the de- of Khambhat in the Arabian Sea. Valsad is located at 20.8 to 21.9 N mand for fresh water due to the rapid growth of population and latitude and 7 2.39 to 73.30.5 W longitude. Area of Valsad district is the accelerated pace of industrialization. Ground water condition 2947.59 sq. kilometers. Total villages are 456. There are five talukas viz. of an area are mainly depends on abstraction, recharge, soil prop- Valsad, Dharmpur, Kaparada, Pardi, Umargaon. Average rainfall is 1500 erties, hydrological characteristic of aquifer, storage capacity etc. to 2200 mm.Main rivers of district are Par, Daman Ganga, and Auranga. The increase of ground water can be achieved by infiltration of rainfall, recharge by seepage, surface flow etc. With the increas- 2) NAVSARI DISTRICT:- ing use of ground water for agricultural, municipal, industrial Navsari district is located at the southernmost tip of Gujarat, near Gulf needs, the annual extraction of groundwater are far in excess of of Khambhat in the Arabian Sea. Navsari is located at 72.43° to 73.00 net average recharge from natural sources (Mohmmad 2012). The ° East (Longitude) 20.07° to 21.00 ° North (Latitude) 40 ° Centigrade groundwater level fluctuation is controlled by recharge and draft (Maximum) Avg. Area of Navsari district is 2657.56 sq. kilometers. of groundwater and the diverse influences on groundwater lev- There are four talukas viz. Navsari, Gandevi, Jalapore, Bansda. Rivers els include meteorology, tidal phenomena, urbanization, earth- Kaveri, Mindhola, Purna, Kharera and AmbicaArea 2,196 sq. km District quakes and external loads Stress and strain in water level due to Headquarter Navsari Talukas. Total villages are 375. Average rainfall is groundwater recharge, discharge and intensity of rainfall are re- 2000 mm.Main rivers of district are Ambika, Puna,Kaveri,Midola etc. flected in groundwater level fluctuation with time. The lowering of groundwater levels has resulted in reduction in individual well yield, growth in well population, failure of bore wells, drying up of dug wells and increase in power consumption(Sukumar 2011). The pre and post monsoon water levels indicate the degree of saturation in aquifer. The extent of saturation in the aquifers is reflected in the status of static water levels. Rainfall is the main source of recharge and the aquifers get saturated by infiltration process. The recharging conditions also vary according to the to- GRA - GLOBAL RESEARCH ANALYSIS X 81 Volume : 2 | Issue : 4 | April 2013 • ISSN No 2277 - 8160 6. From the above graph it is concluded the if rainfall is more average water level is increasing which shows the co relation of rainfall and average water level is good there is also effect of local recharge. For Navsari district Fig 3.9 shows that for pre monsoon average water level is decreasing for all the wells and it is highest for May 1991. For all the wells Fig 3.10 shows that for post monsoon aver- age water level is increasing and it is highest for Oct 1996. For all the wells Fig 3.11 shows that for pre monsoon average water level is decreasing as the distance is increasing and it is highest for 30 to 40 km. For all the wells Fig 3.12 shows that for post monsoon average water level is increasing as the distance is increasing and it is highest for 30 to 40 km. For all the wells which are 0 to 55 km away from sea shore, shows that (Fig 3.13) for average water level is decreasing and it is highest for 30 to 40 km. For all the wells FIGURE 3.1 MAP OF VALSAD AND NAVSARI DISTRICT Fig 3.14 shows average annual water level is decreasing as pass- III METHODOLOG ing of decade and it is highest for year 1991. Apart from studying Water level data of last 20 years of premonsoon and postmon- variation of water level with time, effect of rainfall on the water soon from year 1991 to 2011 at interval of 5 years of 100 wells level is also studied. Fig 3.15 shows the variation of water level has been collected from GWRDC office Surat. From the collected with time and rainfall. Following are the common findings from data following procedure were done to study and analyses the the above study. groundwater fluctuation seasonal and annual and its co-relation with rainfall. 1. In year 1991 the average water level is high but average rainfall is less due to local recharge or high rainfall in the previous year. Average water level has been find out using ms excel for premon- 2. In year 1996 the average water level is decreasing as rainfall in that soon and postmonsoon. year is less Average water level of well has been classified according to dis- 3. In year 2001 the rainfall is less so average water level is also de- tance from sea for premonsoon and postmonsoon. creasing. Graph of average water level vs year has been prepared to study 4. In year 2006 the rainfall is increased so average water level is also yearly water level fluctuation for premonsoon, postmonsoon and decreasing. annual. 5. In year 2011 the rainfall is decreased so average water level is also Graph of average water level vs distance has been prepared to decreased. study distance wise water level fluctuation for premonsoon, post- 6. From the above graph it is concluded that if rainfall is more aver- monsoon and annual. age water level is increasing which shows the co relation of rainfall From average annual rainfall and average annual water level, year- and average water level is good. ly variation in ground water fluctuation due to natural recharging has been studied by preparing graph. The map of 3D surface water level and contour map developed Using Surfer 3-D water surface level, contour map of average an- for annual average water level for Valsad district and Navsari dis- nual water level are prepared to study fluctuation in water level trict is as shown in figure 3.16 to 3.19.