An Evaluation on the impacts of Dry Zone Coastal Ground Water quality changes on sustainability of rural water supply (Kalpitiya Peninsula, Sri Lanka)

Due to the vast utilization and over exploitation, ground water has become a diminishing resource evident from the recent past in the dry zone coastal areas of the world. Forceful powers of both natural and anthropogenic directives have resulted accelerated ground water quality degradation causing fatal diseases and ground water stress as well. On this background the study focus on the main objective of appraising the impact of Dry Zone Coastal Ground Water Quality changes on the water supply for rural inhabitants in terms of spatial dissemination of ground water taking Kalpitiya Peninsula of Sri Lanka as the case study location. The significance of ground water usage in the context of demographic and economic conditions of the area was reviewed using secondary data. In order to appraise the level of ground water stress, a water quality index (WQI) was implemented referenced to the case study region determined on a basis of thirteen [13] physico-chemical parameters namely Electrical Conductivity, Total Dissolved Solids (mg/L), Chloride( mg/L) ,PH, Total alkalinity (TA),Total hardness (TH), Calcium, Magnesium, Sulphate , Fluoride ,Turbidity in NTU, Total Iron in mg/L (as Fe) and Nitrate in mg/L (as N). Thirty four [34] sampling ground water extraction points were monitored covering July, 2014 for dry period & December, 2014 for wet period of Northeast monsoon. Groundwater appropriateness for domestic uses was appraised by using World Health Organization standards for water quality indicators. The results of this study reveals that unsuitable ground water quality (WQI value = 300<) can be observed in more than 75% land areas of the Kalpitiya peninsula according to the Inverse Distance Weightage Interpolation analysis. The highlighted areas depend on ground water as the major water source for the drinking and domestic purposes and also for the agricultural and fisheries industrial needs. This indicates that the Dry Zone Coastal Ground Water table is in constant stress of deprivation and the urban water supply immensely threatened. Accordingly the sustainability of dry zone coastal rural water supply is in a critical need of due attention from the policy makers, planners and users as well.