Assessment of Aquifer-Land Use Composite Vulnerability in Walawe River Basin, Sri Lanka
In the present study, DRASTIC model has been used as a feasible methodology to assess the groundwater vulnerability in the Walawe river basin, Sri Lanka. Geographical Information System (GIS) has been used to develop vulnerability maps, explaining the relative vulnerability of the area. The DRASTIC output concluded that the upper and western parts of the basin show very low vulnerability while the lower part shows higher vulnerability. The groundwater vulnerability maps are compared with the agricultural land-use pattern of the area and it is noticed that the intense agricultural areas and high DRASTIC index areas are overlapped. To emphasise the natural state of the aquifer media as well as the potential pollution of extensive land use, a new indicator has been introduced as Aquifer-Land use Composite Vulnerability Index. This indicator further concludes that the lower part of the Walawe River basin depicts a higher risk for future groundwater quality and hence more attention should be focused to establish monitoring network for adequate groundwater quality control in the area.
Adams, S.B. and A. MacDonalds (1995). Over Exploitation of Aquifers, Technical Report, British Geological Survey, WC/95/3, Keyworth, Nottingham, pp 53.
Al-Adamat, R.A.N., Foster, I.D.L. and S.M.J. Baban (2003). Groundwater vulnerability and risk mapping for the Basaltic aquifer of the Azraq basin of Jordan using GIS, Remote sensing and DRASTIC. Applied Geography, 23(4): 303-324.
Aller, L., Bennett, T., Lehr, J.H., Petty, R.J. and G.. Hackett. DRASTIC: A Standardized System for Evaluating Groundwater Pollution Potential Using Hydrogeologic Settings, EPA/600/2-87/035, Ada, Oklahoma.
Babiker, I.S., Mohamed A.A.M., Hiyama, T. and K. Kato (2005). A GIS-based DRASTIC model for assessing aquifer vulnerability in Kakamigahara Heights, Gifu Prefecture, central Japan. Science of The Total Environment, 345(1-3): 127-140
.
Barber, J.A. (2000). Geological Map of Central and Western Sri Lanka Provisional Series- scale 1:250,000, and seven 1:100,000 map sheets. Geological Survey and Mines Bureau, Sri Lanka, and the British Geological Survey. Journal of Asian Earth Sciences, 18(4): 509-512.
Canter, L.W. and D.A. Sabatini (1990). Use of Aquifer Vulnerability Mapping in Groundwater Management, 1990. Proceedings of the International Conference on Groundwater Resources Management, Bangkok, Thailand.
Chandrajith, R., Dissanayake, C.B. and H.J. Tobschall (2000). Geochemical Mapping of Stream Sediments in the Walawe Ganga Basin. Journal of the Geological Society of Sri Lanka 9.
Cooray, P.G. (1982). Geological Map of Sri Lanka (Ceylon), Scale 1:500,000. Geological Survey Department, Colombo, Sri Lanka.
Dissanayake, C.B. and R. Chandrajith (1999). Medical Geochemistry of Tropical Environments. Earth-Science Reviews, 47: 219-258.
Dixon, B. (2005). Groundwater vulnerability mapping: A GIS and fuzzy rule based integrated tool. Applied Geography, 25(4): 327-347.
ECL (Engineering Consultants Limited) (1995). Water resources inventory study for southern area of Sri Lanka. Report of Southern Province Development Project, Sri Lanka.
Evens, B.M. and W.L. Myers (1990). A GIS Based Approach to Evaluating Regional Groundwater Pollution withDRASTIC. Journal of Soil and Water Cons., 45: 242-245.
Gennaro Piscopo (2001). Groundwater vulnerability map explanatory notes for Lachlan Catchment, Department of Land and Water Conservation, Centre for Natural Resources Publications, p. 19.
Geological Survey and Mines Bureau of Sri Lanka (1996). Geological Map of Sri Lanka 1:10,000 (Provisional Map Series).
Hemakumara, M., Barker, R. and P. Droogers (2001). Ruhuna Benchmark Basin Activities, working paper 27, Water Management Institute (IWMI), Colombo.
JICA (2002). The Study on comprehensive groundwater resources development for Hambantota and Monaragala districts in Sri Lanka. Interim report for Water Resources Board; Ministry of Irrigation and Water Resources Management, Sri Lanka.
Kalinski, R.J., Kelly, W.E., Bograd, I., Ehrman, R.L. and P.D. Yamamota (1994). Correlation between DRASTIC Vulnerabilities and Indicators of VOC Contamination of Municipal Wells in Nebraska. Ground water, 32: 31-34.
Kulatunga, N. (1998). Hydrology of a metamorphic terrain: case study from Hambantota, Sri Lanka. Journal of the Geological Society of Sri Lanka, 1(2): 12-19.
Mahaweli (1995). Water Resources Management in the Mahaweli Programme. Report of Mahaweli Development Authority.
Melloul, A.J. and M. Collin (1998). A proposed index for aquifer water-quality assessment: The case of Israel’s Sharon region. Journal of Environmental Management, 54(2): 131-142.
Panabokke, C.R. (2002). Review of data on soils and geology in the basin area and their relevance to groundwater in the area; case study, Ruhuna basins. Proceedings of the workshop of World Water Assessment program, Sri Lanka, pp. 63-83.
Ranjan, S.P. (2002). Assessment of groundwater resources in Walawe River basin, Sri Lanka. MSc Thesis. School of Engineering, Asian Institute of Technology, Thailand, 85 p.
Rosen, L. (1994). A Study of the DRASTIC Methodology with Emphasis on Swedish Conditions. Groundwater, 32: 278-285.
Rupert, M.G. (2001). Calibration of the DRASTIC Groundwater Vulnerability Mapping Method. Groundwater, 39: 625-630.
Secunda, S., Collin, M.L. and A.J. Melloul (1998). Groundwater vulnerability assessment using a composite model combining DRASTIC with extensive agricultural land use in Israel’s Sharon region. Journal of Environmental Management, 54: 39-57.
Statkraft Groner (2000). Sri Lanka Third Water Supply and Sanitation Project—Water Resources Management Component: Groundwater Walawe River Basin, Report produced for the National Water Supply and Drainage Board and the Water Resources Secretariat, Sri Lanka. (Unpublished report).
Thirumalaivasan, D., Karmegam, M. and K. Venugopal (2003). AHP-DRASTIC: software for specific aquifer vulnerability assessment using DRASTIC model and GIS. Environmental Modelling & Software, 18(7): 645-656.
Vrba, J. and A. Zaporozec (Eds) (1994). Preparation and Use of Groundwater Vulnerability Maps. International Contribution to Hydrogeology, Vol. 16, Hannover, UNESCO/IAH.
Wijayathilake, D.R. (2001). Proceedings of the Regional Workshop on Integrated Plant Nutrient Systems, Sep 2001, Bangkok.
Wilchelm, L.F.B., Magnuszewski, A. and S. Zober (2000). The structure and function of the Vistula River floodplain near Plock, Poland. Ecological Engineering, 16: 159-166.