Asian Journal of Water, Environment and Pollution, Vol. 1, No. 1 & 2, pp. 119-122.

Sources of Groundwater in Crystalline Hard Rocks of Area,

U. de S. Jayawardena Department of Civil Engineering, Faculty of Engineering University of , Peradeniya, Sri Lanka * [email protected]

Received March 31, 2004; revised and accepted June 10, 2004

Abstract: Hydrogeological investigations were carried out to obtain sufficient information on groundwater availability in the fractured metamorphic rocks in Kandy district of Sri Lanka. 47 boreholes were drilled with the average depth of 90 metres and 24 high yielding wells were selected and long term pumping tests were carried out for each well using standard methods. The calculated total of pumping rates from all wells was 8150 metric cubes per day. Pump installation depth and dynamic water levels were also calculated and the pumping time was limited for 16 hours per day allowing eight hours for recovery. These groundwater supplies have been connected to the main public water supply and no serious problems have been recorded so far since the beginning of this project. This indicates that there are many hidden groundwater sources in hard rocky areas for future. Some recommendations to maintain the wells are given here.

Introduction Objective The objective of this paper is to determine hydro- During the period of 1981-1990 which was declared as geologically more favourable locations for high yielding the International Decade for Water Supply and Sanitation, deep wells which are to be used as sources for the Sri Lanka was able to launch several water supply and proposed piped water supply scheme in the areas coming sanitation projects for the benefit of rural people in the under Pathadumbara electorate of the Kandy district, Sri country. The donor of one such project is the Finnish Lanka. International Development Agency (FINNIDA) with the object of providing safe drinking water and sanitation in The Project the Kandy district. The project works were undertaken by Soil and Water Limited, Finland in 1987. The projects According to the project plan of the Kandy District Water Supply and Sanitation Project, the area of Kandy district involved planning and designing of water supply for the has been divided into Assistant Government Agent total area of Kandy district. The project supervision for (AGA) divisions to carry out water resources studies Finland was done by FINNIDA and it was named as including identification of communities, their require- “Kandy District Water Supply and Sanitation Project ments and areas to be implemented. (KDWSSP)”. Hydrogeological investigations were Pathadumbara AGA division, which is situated north- carried out by this project for locating groundwater east of Kandy district in the central hills of Sri Lanka, is resources and determination of their properties for the one of the priority areas belonging to the project. The realization of water supply in the area belonging to the project area is characterized by large and small river Kandy district. basins with ridge and valley topography. The main road 120 U. de S. Jayawardena

of the valleys are lying along the lineaments. The occurrence of groundwater in the project area is restricted to joint systems of which the density and the orientation vary according to the rock types and locality.

Method of Study

Hydrogeologically favourable sites were initially located after a thorough interpretation of aerial photographs, satellite imageries, geological maps and the previous reports. The site locations were confirmed by field Figure 1: The project area, Pathadumbara electorate investigations, studying the geomorphological, geologi- in Kandy district. cal and geostructural setting of the area. Geologically from Kandy to Matale is running through the area. The the areas where biotite gneiss, migmatitic gneiss and valleys and floodplains of the main rivers and streams quartzite are underlain were selected because those are consist of belts of alluvial low-lands. The project area the highly fractured rocks in the investigated area. Deep covers nearly 46 square kilometres. The mean annual groundwater may occur only under favourable structural rainfall in the project area is about 1940 mm. The average conditions. Therefore rock contact zones, fractured zones day temperature varies from 20° C to 26° C during the and highly jointed places of the regional rocks were year. The humidity is relatively high and it is generally considered for site selections. The valleys lying along above 60%. The population of Pathadumbara AGA lineaments are the most suitable geomorphological division is about 59,000 (in 1981 census) and the condition for shallow and deep groundwater. Most of projected population for the year 2010 will be approxi- the sites were selected within these valleys. The locations mately 92,100. The estimated water demand for the of springs within the region were also considered as project area is 10,000 cubic metres per day (Soil and favourable sites. Water Ltd., 1990). The deep wells have been categorized into hand pump Drilling borehole wells and production borehole wells. Hand Based on the above investigations, 47 sites have been pumps are installed for the low yielding wells (generally selected for deep drilling. The drilling operations have well yield is above four litres per minute) and electric been conducted using DTH drilling rigs and compressed water pumps are installed for production wells (very high air. The diameter of boreholes were 115-200 mm and the yields, above 100 l/min) for distribution of water through average depth was 90 metres. All boreholes were flushed a distribution network after pumping to a storage tank. and cleaned after the completion of drilling by In addition to the borehole wells, large diameter shallow compressed air and then flushing yield were measured. wells are recommended for some locations where The deep wells have been categorized into hand pump accessibilities are poor. borehole wells on the basis of flushing yields. All the wells in which the flushing yields were more than 100 General Geology litres per minute were selected as production wells. In general, this area is underlain by typical Precambrian Pumping Tests metamorphic rocks (Cooray, 1967). The major rock types Short and long term pumping tests were carried out for in this area are biotite gneiss, hornblende biotite gneiss, the selected production wells to study the characteristics charnockitic gneiss, quartzite, granulitic gneiss, garnet of the aquifers. Short term pumping tests (step draw- sillimanite gneiss and migmatitic gneiss. The structural settings and trend lines of the rocks in the project area down) were done to decide the suitable pumping rates exhibit a good morphotectonic relationship to the and levels for long term pumping tests. Finally the topographical features. The strike of most of the rocks recovery was measured. shows 325° direction and having deep dips ranging from After analyzing the data of step drawdown tests, 60°-80°. Two sets of major joint (lineaments) patterns suitable pumping levels and rates were chosen for long exist in the area with strike directions 45° and 135°. Most term pumping tests. Then long term pumping tests were Sources of Groundwater in Crystalline Hard Rocks of Kandy Area, Sri Lanka 121

Figure 2: Water level changes during test pumping at Polgolla. started for all the high yielding wells. The drawdown the first hour of pumping in each well. Then it takes atleast and water levels of all wells including nearby shallow six days to reach the maximum drawdown or the constant wells were measured with the time. All drawdown dynamic water levels. The dynamic water levels after measurements were taken with respect to the ground six days were fluctuating very slowly. Therefore any surface. A standard method was used to carry out the damage will not occur to the aquifer system from these tests (Helweg et al., 1982). All long term pumping tests pumping rates. This confirms that the selected pumping were carried out for nearly a period of one month and rates from the initial step-drawdown tests are suitable recovery measurements were recorded until the water for continuous pumping. levels reached the original static water levels. Some Generally the pump should be kept free for some time boreholes were used as observation wells during pumping to break the continuous pumping and maintenance tests. purposes. If not it may reduce the pump efficiency and create some mechanical damages to the pump. Hence Analysis the pumping time and recovery time per day should be Long term pumping tests data were analyzed by using found from these data. The maximum time for ground- the Cooper-Jacob’s equations (Todd, 1980). The water pumping and minimum time for the recovery of drawdown of dynamic water level with time was used to the same water column per day was observed using the calculate the transmissivity. The curves were drawn on time-drawdown and time-recovery data for each well. normal and semi-log graph sheets respectively to As mentioned earlier, first hour of pumping reduces the understand the aquifer properties. The transmissivity water level 1/3rd of maximum drawdown and needs a higher than 10 m3/day/m were selected as suitable wells longer period to reach the same initial water level. But it for the proposed water supply scheme. is observed that the drawdown from 2nd hour to 16th To calculate the amount to be pumped per day, the hour of pumping could be recovered within eight hours time of recovery period and the maximum drawdown of in most of the wells. Therefore 16 hours pumping and each well during the long term pumping period were eight hours recovery per day can be recommended. carefully analyzed. Table 1 shows the recommendations of pumping capacity, pump installation depth and the dynamic water level for Results and Discussion each well. The total maximum pumping capacity from all the The time-drawdown data indicated that the water levels wells were 8150 metric cubes per day. Using these rates, decrease about 1/3rd of the maximum water levels within only 16 hours per day were recommended for the 122 U. de S. Jayawardena

Table 1: Recommendations for each production well

Well No. Recommended pumping Recommended pump Dynamic water capacity for 16 hours installation depth level (m) pumping period below ground (m3/day) level (m) 8005 1000 25 20 8006 1000 25 20 2112 200 45 35 2113 250 45 35 2114 275 45 35 2115 525 45 35 2118 300 45 35 2107 250 35 35 2108 500 35 35 2167 250 45 35 2169 250 45 35 2100 500 45 35 2120 500 45 35 2175 100 45 35 2135 200 45 35 2139 850 45 35 2140 300 45 35 2102 125 45 35 2123 200 45 35 2133 100 45 35 2134 125 45 35 2127 250 45 35 2125 100 45 35 operation of water pumps and the rest of the time (eight amount to be extracted with a proper maintaining system hours) was allowed for recovery. for a continuous public water supply scheme. This This groundwater supply scheme was started about amount may not be enough for the future with the ten years ago and has been connected to the main public increasing rate of population. water supply scheme. Since then people of the area are using this resource for their domestic purposes. No serious problems or complaints have been reported so far since the beginning of the project. Therefore this is a References very good practical example for the occurrence of hidden Cooray, P.G. (1967). An introduction to the Geology of Ceylon. groundwater resources in the hard crystalline rocky areas. Ceylon National Museums Dept., Colombo. However to use this groundwater for a longer period, the Helweg, O.G., Scott, V.H. and J.C. Scalmanini (1982). wells should be maintained properly. Improving well and pump efficiency. American Water Works and Association, USA. Conclusion Soil and Water Ltd. (1990). Report on the study of groundwater resources in Pathadumbara AGA’s Division in Kandy This project was carried out to provide safe water for the district. Kandy District Water Supply and Sanitation Project people living in a part of Kandy district. The investiga- Report No. RI-80-00/41. tions clearly indicate the occurrence of hidden ground- Todd, D.K. (1980). Groundwater Hydrology. John Wiley & water sources in the fractured crystalline rocks and the Sons, UK. Environmental Information System (ENVIS)

Realizing the importance of environmental information, Management Capacity Building Technical Assistance the Government of India, in December, 1982, established Project (EMCBTAP) since January 2002. The program- an Environmental Information System (ENVIS) as a plan me is designed to give an impetus to local, national and programme. The focus of ENVIS since inception has been world environmental information with an aim to: on providing environmental information to decision l Network identified organizations/institutions in aca- makers, policy planners, scientists and engineers, demic, private and NGO sector and state government research workers, etc. all over the country. department, who have a holding on environmental data Since environment is a broad-ranging, multi- and information. disciplinary subject, a comprehensive information system l Disseminate information databases on different on environment would necessarily involve effective environment related subject areas and provide on-line participation of concerned institutions/organizations in query response. the country that are actively engaged in work relating to different subject areas of environment. ENVIS has, To achieve this aim 85 ENVIS Nodes have been set therefore, developed a network of such participating up till date. The Nodes are classified as: institutions/organizations for the programme to be ENVIS Centres: Out of the 25 ENVIS centres, 24 meaningful. 25 ENVIS centres have been established to have consented to serve as ENVIS-Nodes on assigned cover the broad subject areas of environment with a Focal subject areas. Point in the Ministry of Environment & Forests. ENVIS Institutional Nodes: 34 peer institutes which Both the Focal Point as well as the ENVIS centres have expertise on specific subject areas form this segment have been assigned responsibilities to achieve the long- of the Nodes. term and short-term objectives. The Focal Point offers a ENVIS NGO Nodes: 21 NGOs are networked number of services. together who work on varied subjects related to ENVIS India, due to its comprehensive network, has environment. been designated as the National Focal Point (NFP) for ENVIS Government Nodes: 30 Government depart- INFOTERRA, a global environmental information ments form this segment at present which are to prepare network of the United Nations Environment Programme the State of the Environment Report for the State. (UNEP). The activities of NFP among others include All the Nodes have also been categorized under seven providing environmental information to users in South- heads to enable networking of Nodes working on related Asia sub-region. ENVIS India has also been designated subject areas. The mission of ENVIS is to support and as the Regional Service Centre (RSC) of INFOTERRA facilitate the diverse group of clientele from policy of UNEP in 1985 for the South Asia Sub-Region makers to researchers and industries and common man countries. at national and international level on a possible range of environmental data and information through a nation- A Programme on Environment Management wide web-enabled network. The on-going World Bank Capacity Building of the World Bank (ENVIS- assisted programme of the ENVIS aims to provide a EMCB) comprehensive environmental information data base ENVIS (Environmental Information System) is under the identified subject areas, local conditions and implementing the World Bank assisted Environment issues pertaining to the environment of the country. 124 Asian Journal of Water, Environment and Pollution

List of ENVIS Centres

S.No. Name & Address Subject Area Email 1. Assam Science, Technology and Environmental Status of Environment [email protected] Council, Guwahati and Related Issues (SERI) 2. Bihar State Pollution Control Board, Patna (SERI) [email protected] 3. Centre for Environmental Studies (CES), (SERI) [email protected] Bhubaneshwar 4. Chhattisgarh Environment Conservation Board (SERI) 5. Department of Environment, Chandigarh (SERI) [email protected] 6. Department of Environment, Daman and Diu (SERI) 7. Department of Environment, Govt. of Delhi (SERI) 8. Department of Environment, Tamil Nadu (SERI) [email protected] 9. Department of Environment, West Bengal (SERI) [email protected] 10. Department of Environment and Forest, (SERI) [email protected] Andaman and Nicobar, Port Blair 11. Department of Forests, Environment and (SERI) [email protected] Ecology, Govt. of Karnataka, Bangalore 12. Department of Forests, Environment and (SERI) [email protected] Wildlife, Sikkim, Gangtok 13. Department of Science, Technology (SERI) [email protected] and Environment, Bardez, Goa 14. Department of Science, Technology (SERI) [email protected] and Environment, Pondicherry 15. Directorate of Environment and Remote (SERI) Sensing, Srinagar, Jammu and Kashmir 16. Disaster Management Institute (DMI), Bhopal (SERI) [email protected] 17. Environment and Ecology Wing, Dept. of Forests and Environment, Imphal, Manipur (SERI) [email protected] 18. Environment and Forest Department, Mizoram (SERI) [email protected] 19. Environment Department, Maharashtra (SERI) [email protected] 20. Environment Directorate, Uttar Pradesh (SERI) [email protected] 21. Environment Protection Training and Research (SERI) [email protected] Institute (EPTRI), Hyderabad 22. Gujarat Ecology Commission, Vadodra (SERI) [email protected] 23. Ministry of Forest and Environment Govt. (SERI) of Jharkhand, Ranchi-834 002, Jharkhand 24. Nagaland Institute of Health and Social (SERI) Welfare, Kohima 25. Punjab State Council for Science and Technology, Chandigarh (SERI) [email protected] 26. Rajasthan State Pollution Control Board, Jaipur (SERI) [email protected] 27. Science, Technology and Environment (SERI) [email protected] Committee, Govt. of Kerala, Thiruvananthapuram 28. State Council for Science, Technology (SERI) [email protected] and Environment, Shimla 29. Tripura State Pollution Control Board, Agartala (SERI) [email protected] 30. Uttaranchal Pollution Control Board, Dehradun (SERI) [email protected] 31. Botanical Survey of India (BSI), Howrah Floral Biodiversity 32. Central Building Research Institute (CBRI), Fly Ash [email protected] Roorkee 33. Central Pollution Control Board (CPCB), Delhi Control of Pollution [email protected] (Water, Air and Noise) (contd.) Environmental Information System (ENVIS) 125

(contd.)

34. Centre for Advanced Studies in Marine Biology Mangroves, Estuaries, [email protected] (CASMB), Annamalai Unniversity, Parangipettai Lagoons, Coral Reefs 35. Centre for Ecological Sciences, Indian Institute Western Ghats and [email protected] of Science (IIS), Bangalore Biological Diversity 36. Centre for Environmental Studies (CES), Biodegradation of wastes [email protected] Anna University, Chennai and EIA 37. Centre for Mining and Environment (CME), Environmental Problems Indian School of Mines, Dhanbad of Mining 38. Department of Environmental Sciences, Kalyani Environmental [email protected] University, Kalyani, Dist. Nadia, WB Biotechnology 39. Department of Geology, University Marine Ecosystem [email protected] of Kerala, Thiruvananthapuram 40. Department of Zoology, University Micro-organisms and [email protected] of Madras, Chennai environmental management 41. Forest Research Institute (FRI), Forestry [email protected] Dehradun 42. G.B. Pant Institute of Himalayan Environment Himalayan Ecology [email protected] and Development, Almora 43. Gujarat Cleaner Production Centre Cleaner Production [email protected] (GCPC), Gandhi Nagar and Technology 44. Indian Institute of Chemical Technology Bioinformatics - [email protected] (IICT), Hyderabad Vector Control 45. Indian Institute of Foreign Trade International Trade [email protected] (IIFT), New Delhi and Environment 46. Indian Institute of Forest Management Grassland Ecosystems [email protected] (IIFM), Bhopal and Agro-forestry 47. Indian Institute of Management (IIM), Environmental Manage- [email protected] Bangalore ment in Management Schools 48. Indian Institute of Tropical Acid Rain and Atmospheric [email protected] Meteorology (IITM), Pune Pollution 49. Industrial Toxicological Research Toxic Chemicals [email protected] Centre (ITRC), Lucknow 50. Institute for Ocean Management (IOM), Coastal Regulation Zone [email protected] Anna University, Chennai Management 51. Madras School of Economics (MSE), Environmental [email protected] Chennai Economics 52. National Botanical Research Indicators of Plant [email protected] Institute (NBRI), Lucknow Pollution 53. National Environmental Engineering Hazardous Waste [email protected] Research Institute (NEERI), Nagpur 54. National Institute of Occupational Health Environmental and [email protected] (NIOH), Ahmedabad Occupational Health 55. National Law School of India University Environmental Law [email protected] (NLS), Bangalore 56. National Museum of Natural History Museology with Special [email protected] (NMNH), New Delhi Reference to Natural History 57. National Ship Design and Research Marine Offshore [email protected] Centre (NSDRC), Visakhapatnam Ecosystem (contd.) 126 Asian Journal of Water, Environment and Pollution

(contd.) S.No. Name & Address Subject Area Email 58. Punjab State Council for Science Water Resource Manage- [email protected] and Technology, Chandigarh ment in Agriculture 59. Regional Research Laboratory (RRL), Coastal Shelterbelt [email protected] Bhubaneshwar 60. School of Environmental Sciences (JNU), Biogeochemistry [email protected] Jawaharlal Nehru Univ., New Delhi 61. School of Planning and Architecture (SPA), Human Settlement [email protected] New Delhi 62. State Council of Science and Technology Ecotourism [email protected] for Sikkim, Gangtok 63. Wildlife Institute of India (WII), Dehradun Wildlife and Protected [email protected] Area Management 64. Zoological Survey of India (ZSI), Kolkata Faunal Biodiversity [email protected] 65. Bombay Natural History Society (BNHS), Avian Ecology including [email protected] Mumbai Inland, Wetlands 66. Centre for Environment Education (CEE), Environmental Education [email protected] Ahmedabad 67. Centre for Media Studies (CMS), New Delhi Communication and [email protected] Electronic Media 68. Centre for Symbiosis of Technology Women and Environment [email protected] Environment and Management, New Delhi 69. Consumer Education and Research Centre Eco-Labeling and [email protected] (CERC), Ahmedabad Promotion of Eco- Friendly Products 70. CPR Environmental Education Centre Conservation of [email protected] (CPR), Chennai Ecological Heritage and Sacred Sites in India 71. Development Alternatives (DA), Environmentally Sound [email protected] New Delhi Appropriate Technologies and Sustainable Livelihoods 72. Environment Management Division, Industry-Government [email protected] Confederation of Indian Industries Environmental Interface (CII), New Delhi 73. Environment Protection Training Eastern Ghats Ecology [email protected] and Research Institute (EPTRI), Hyderabad 74. Environmental Management and Policy Capacity Building [email protected] Research Institute (EMPRI), Bangalore for Environment Management 75. Foundation for Revitalization of Local Conservation of [email protected] Health Traditions (FRLHT), Bangalore Medicinal Plants 76. Indian Centre for Plastic in the Environment Management of Plastic, [email protected] (ICPE), Mumbai Polymer Wastes and Biopolymers, Impacts of Plastic on Eco-System 77. Indian Environmental Society (IES), Delhi Panchayati Raj and [email protected] Environment 78. Institute of Advance Study in Science Environmental Problems [email protected] and Technology (IASST), Guwahati in Tea Gardens (contd.) Environmental Information System (ENVIS) 127

(contd.) 79. International Institute for Population Population and [email protected] Sciences (IIPS), Mumbai Environment 80. National Solid Waste Association Urban Municipal [email protected] of India (NSWAI), Mumbai Waste Management 81. Salim Ali Centre for Ornithology and Wetland Ecosystem [email protected] Natural History (SACON), Coimbatore 82. Sulabh International Institute of Health Hygiene, Sanitation and [email protected] and Hygiene, New Delhi Environment, Sewage Treatment Systems and Technology 83. The Energy Resources Institute (TERI) Renewable Energy [email protected] New Delhi and Environment 84. Waterfalls Institute of Technology Environmental Audit and [email protected] Transfer (WITT), New Delhi Accounting 85. World Wide Fund for Nature - India Non Government [email protected] (WWF), New Delhi Organisations Media and Parliament Matter Related to Environment CAPITAL PUBLISHING COMPANY Recent and Forthcoming Publications on Water, Environment and Pollution

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