DEPLETING GROUND WATER SCENARIO OF UDUMALPET TALUK, TIRUPPUR DISTRICT, TAMILNADU. T.S.Badrinarayanan, Geoscientist- E-mail
[email protected]
INTRODUCTION: A country’s growth and development primarily depend on agriculture and food production. Our country is a agrarian country and agriculturists are the backbone of our nation. 80% of the water resources are consumed by agricultural sector. Ground water is the only viable alternative source for surface water during crisis due to failure of monsoon and adverse seasonal conditions. Ground water is one of the basic component of life support system, occurs in the subsurface with in sediments and rocks. Since 1950 Global water use has more than tripled. There is likely to be a major shortage in Global supplies of fresh water by 2025 AD. Spreading water scarcity will make it more difficult to impound food production and more, with the water table falling and aquifer depleting. In drought prone areas and periodic recurrence of drought especially in hard rock terrains, the ground water scenario will be very worst. The ground water occurrence and potential of an area mainly depend upon so many factors like the hydrogeological conditions, topography, rainfall, soils, recharge and discharge. It is suggested that instead of continuously reaching out for more water, the challenge is to do more with less by conserving and recycling water and using it more efficiently including the highly efficient drip irrigation in agriculture. UDUMALPET TALUK: Udumalpet taluk comes under Tiruppur district, a recently formed district of Tamilnadu, was. Previously. under Coimbatore district. Udumalpet is the headquarters of Udumalpet taluk and popularly known as” Poor man’s Ooty” due to its cool climatic conditions. Udumalpet taluk is in south western end of the Tiruppur district. Udumalpet usually referred as Udumalai, is about 65 kms south of the district head quarters Tiruppur and is in between Pollachi and Palani, one of the six abodes of Lord Muruga. The altitude of Udumalpet is 1208 feet above MSL and the total area of the taluk is 1436.76 square kms. Administratively Udumalpet taluk has 3 panchayat unions [blocks] namely, Gudimangalam, Madathukulam and Udumalpet. The Amaravathi River, a tributary of the river Cauvery, is flowing east of Udumalpet bifurcating Udumapet and Palani taluks. Agriculture is the major occupation of rural populace. The main cerals are
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paddy and corn. Commercial crops like cotton, sugarcane and oil seeds are cultivated. Coconut tree farms and plantations are the common sights in villages. The chief sources of irrigation are wells, bore wells, river, canals and rain fed tanks. The PAP [Parambikulam-Aliyar Project] a network of irrigation canal system is a boon to the agriculturists of Pollachi, Palladam and Udumalpet taluks. For Udumalpet municipal drinking water supply scheme, Thirumurthy reservoir is the source. Rural water supply schemes have been provided from Thirumurthy, Amaravathi dams and as well as from the Aliyar river. Thirumurthy falls water will be very sweet and tasty like mineral water. The EC, TDS and Cl parameters are 83, 58 PPM & 05 PPM respectively.
UDUMALPET TALUK
RAIN FALL: The annual normal rain fall of the old Coimbatore district is 702 mm based on the IMD data for 50 years. North east monsoon predominantly contributing 46% of annual rain fall, south west monsoon contributing 28% and pre monsoon rains 26%. [Source CGWB]. As per CGWB statistical analysis [APP 2005-2006] of long term of rain fall data for 100 years from 1901 to 2000, the normal rain fall of Coimbatore district
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ranges from 560.3 to 866.6 mm. The total drought year over the Coimbatore district ranges from 11 to 22%. The frequency of occurrence is rather high. Since Nilgiris place Coimbatore in the rain shadow region, there are water shortages in water supply with regard to domestic, industrial and agricultural sectors. RIVERS: Major parts of Udumalpet taluk falls in Parambikulam- Aliyar basin. The river Amaravathy originates in the Anjana Valley in Kerala between Anamalai hills & Palanis of Western Ghatts, is flowing about 13 kms east of Udumalpet and is ephemeral in nature. Chinnar also raises in Anamalais joins with Amaravathy River. The river Palar, a tributary of Aliyar, originates from the Anamalais and flows north westward through Udumalpet & Pollachi taluks & confluences with Aliyar near Ambarampalayam. Nallar another river rising in Anamalais confluences with Palar river near Devanurpudur. The Thirumurthy dam has been constructed on the Palar River. . Uppar odai and Perumpallam are the two major streams. GEOLOGY OF UDUMALPET TALUK: The Udumalpet taluk is a hard crystalline rock terrain, underlain by the Peninsular gneissic complex of Archean age, the oldest formations. The predominant rock types are biotite gneiss, granite gneiss, hornblendebiotite gneiss, granites and charnockites. Intrusives in the form of pegmatites, quartz and pink granites intrude the country rocks. Kankar and soil are the recent formations. Kankar is a hard white buff colored material rich in calcium carbonate. Kankar is commonly observed in major parts of Gudimangalam and Udumalpet unions along the Uppar odai and perumpallam. Kankar is generally impervious due to its massive and compact nature. Major parts of taluk is covered by black cotton soil which is very clayey in nature.The taluk forms a highly tectonised belt and hence the structure of rocks are very complex. The regional trend of foliations is north east- south west with a south easterly dip. Since this taluk is tectonically disturbed major geological structures like plunging folds and lineament systems are present. Two major lineaments in Gudimangalam union, Poolavadi- V.Vallakondapuram lineament and Pukkulam- Venasapatti- Sadayapalayam lineament and one minor lineament along Periyakottai in Udumalpet union, which play a pivotal roll in the potential and movement of ground water. HYDROGEOLOGY: Almost all the rock types in the taluk show effect of weathering. The degree and intensity of weathering vary depending on the structure, chemical and
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mineralogical components of rock. The intensity of weathering is high in the tectonically disturbed zones. The ground water occurs mainly under unconfined conditions in the weathered mantle, joints and fractures. The general water table follows the topographic configuration. The average depth to water table of Gudimangalam, Madathukulam and Udumalpet unions are 9.89, 6.08 & 10.33 meters below ground level [bgl] respectively, during 1995 May as per TWAD Board’s report. As per the TWAD Board seasonal water level monitoring report for the period 1991 to 2000 of old Coimbatore district the average water level [May] has dropped below 20 meters bgl, in 91, 92, 93. 96 & 2002. Based on the ground water development categorization of blocks, Gudimangalam and Udumalpet unions fall under Critical [exploitation between 90 to 100%]
category and
Madathukulam union falls under Safe [exploitation < 70%] category. BORE WELL STATISTICS, UDUMALPET TALUK 2010
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
1988
1987 200 250 300
DEPTH IN FEET BGL.
350 400 450 500 550 600 650 700 750
Graph showing the year wise average depth of bore wells- 1988 to 2009. ANALYSIS OF THE BORE WELL STATISTICS: To get a clear picture about the increase in bore well depth year after year, an analysis has been attempted. For this purpose 107 bore wells drilled in Udumalpet taluk for agricultural and water supply purposes during the years 1988, 1990 to 1992, 1994 to 1997, 1999 to 2009 altogether
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totally for 19 years, have been taken into account. The above graph shows the depth versus year of drilling and for each year the average depth of bore wells has been incorporated. The analysis reveals that there is a general increasing trend in depth from 1992 to 2004 and the depth has reached the maximum of 716 feet in 2004 which witnessed a severe drought. A bore well drilled at Pukkulam in Gudimangalam union for agricultural purpose to a depth of 600 feet in 2000 which discharged 470 lpm. As the bore’s discharge was very poor in 2004, the bore was rejuvenated by redrilling up to a depth of 1000 feet. But even after, there was only poor discharge. When the bore hole was scanned by a bore hole video camera for hydrofracturing feasibility studies, it was observed that the static water level was 459 feet bgl. After subsequent monsoons the depleted aquifer got recharged and now it has been discharging good yield. A bore well drilled at Gudimangalam for agricultural purpose to a depth of 900 feet in October 2009 yielded 11/2’’ [23 lpm]. The first spring was struck @ 540 feet & the second @ 730 feet. GROUND WATER POTENTIALS: The ground water potential mainly confines to the geological structures like, folds, faults and lineaments which serve as conduits for ground water movement especially in hard rock areas. In Udumalpet taluks, the bore wells drilled in the lineament zones have discharged good yields ranging from 100 to 500 lpm. In Pukkulam- Sadayapalyam lineament 90 % of the bore wells drilled have yielded > 100 lpm. In the Poolavadi - V.vallakondapuram lineament also 50 % of the bore wells drilled have yielded > 200lpm. Many bore wells have been drilled in this lineament zone for rural water supply by TWAD Board.
A bore well drilled at Bodipatti of Udumalpet
union, for agricultural purpose in 2002, to a depth of 940 feet has yielded 612 lpm, which is the highest yield struck among this 107 bore wells drilled from 1988 to 2009. The high yield may be attributable to deep seated fractures in charnockites. The success rate of bore wells in the lineament area is nearly 98%. The bore wells drilled in Pukkulam and Sanuppapatti Vallakondapuram areas have met with boulders of big sizes & potential aquifers at deeper depths confirming the deep lineaments. In one of the bore wells drilled @ Maalaikoil near Pedappampatti, to a depth of 220 feet in 1990 has yielded 500 lpm and @ a depth of 210 feet coarse sand with gastropod shells have been encountered. But after subsequent droughts those aquifers got depleted. The potential of the aquifers were such that, drilling could not be proceeded due to high yield.
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GROUND WATER QUALITY: Most of the ground water of Gudimangalam & Udumalpet unions is generally brackish to saline in nature, making it not suitable for drinking purpose. The salinity may be attributable to the black cotton soil. Generally fluoride content in Lingamanaickenpudur belt of Gudimangalam union is high exceeding the permissible limit of 1.5 ppm. Excess fluoride content causes dental & skeletal flourosis. The reason for the excess may be attributable to the presence of fluro apatite in granite gneiss and florin contents in biotite gneiss. The physio- chemical analysis of Pukkulam [Gudimangalam union] bore well water sample shows that some parameters like EC, TDS & Cl are 4480, 3136 ppm & 746 ppm respectively & so not potable due to excess EC & TDS. Another sample, open well @ chinnaveerampatti in Udumalpet union shows very excess EC, TDS & Cl, 8680, 6076 ppm & 2035 ppm respectively, which is highly saline because of complete black cotton soil. A DRIED UP AGRI WELL.
INJECTION WELL. .
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CONCLUSION: This is a general over all picture of ground water extraction in Udumalpet taluk of Tiruppur district. Already they have gone up to 1000 feet to tap water. From this study it may be seen that, how the agriculturists have been struggling to get water, who are in doll drums. In the recent past many agricultural lands have been disposed for wind mill erection to generate power. Dense population of Wind mills can be seen in Udumalpet taluks and it is mushrooming. In such drought prone area with deep water table, utmost care and attention must be given to the proper management of water resources. Good drip irrigation techniques and conservation measures have to be taken up. The environment and ecology have to be protected to get rainfalls. Now a days lot of reports of suicide by the agriculturist for want of water are coming up. To put an end to this menace, we must do something positive for interlinking of rivers. As suggested earlier, instead of continuously reaching out for more water, the challenge is to do more with less, by conserving water and using it more efficiently. Since major extensive lineaments are present, ground water may be recharged
by injection wells. The
defunct wells & bore wells may be used as recharge wells.
• Replete before deplete. •
Water should no longer being viewed as just water.
•
As a natural resource -viewed as a commodity -used rationally, priced appropriately, managed,
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sources recharged and reused as much as possible and wherever possible.
T.S.BADRINARAYANAN, GEOSCIENTIST, B2 GEO TECH SERVICES, KOLLIDAM SIRKALI TALUK, NAGAI DSITRICT, TAMILNADU, PIN- 609 102, MOB- 94430 46102
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