Isotope and chemical assessment of natural water in the Jaffna Peninsula in northern Sri Lanka for groundwater development aspects

Groundwater-Based Drinking Water Supply in Sri Lanka: Status and Perspectives

Drinking water is largely from groundwater in Sri Lanka, so quality management is of great concern. In order to achieve the 6th goal of United Nations (UN) Sustainable Development Goals (SDG), more efforts are being undertaken to secure drinking water quality. In this paper, the current status, challenges and opportunities of groundwater quality management and improvement in Sri Lanka were reviewed and discussed, based on previous studies. There are Ca-HCO3 type, Ca–Mg-HCO3 type and Na–SO4–Cl type groundwater dominated in the wet zone, intermediate and the dry zone, respectively. Elevated levels of hardness, fluoride, DOC, and alkalinity, and salinity are reported in the groundwater in the dry zone controlled by geology and arid climate. Although groundwater in some regions contain significant levels of nitrates, arsenic, cadmium and lead, the majority remain at acceptable levels for drinking purposes. As for treatment technologies, existing membrane-based drinking water treatment technologies such as RO (Reverse Osmosis) stations can produce safe and clean drinking water to the community, but this has still a limited coverage. To achieve a safe drinking water supply for all, especially in rural communities of Sri Lanka under the 6th goal of the UN SDG, more efforts in building up the infrastructure and man power are needed to monitor and assess groundwater quality regularly so as to develop management strategies. Research and development can be directed towards more cost-effective water treatment technologies. Protection of groundwater from being polluted, and educational and awareness programs for the stakeholders are also essential tasks in the future.

Modeling and Mapping of Soil Salinity and its Impact on Paddy Lands in Jaffna Peninsula, Sri Lanka

Soil salinity is a major threat to land productivity, water resources and agriculture in coastal areas and arid and semi-arid regions of the world. This has a significantly negative effect on the land and causes desertification. Monitoring salt accumulation in the soil is crucial for the prevention of land degradation in such environments. This study attempted to estimate and map soil salinity in Jaffna Peninsula, a semi-arid region of Sri Lanka. A Partial Least Squares Regression (PLSR) model was constructed using Sentinel 2A satellite imagery and field-measured soil electrical conductivity (EC) values. The results showed that satisfactory prediction of the soil salinity could be made based on the PLSR model coupled with Sentinel 2A satellite imagery (R2 = 0.69, RMSE = 0.4830). Overall, 32.8% of the land and 45% of paddy lands in Jaffna Peninsula are affected by salt. The findings of this study indicate that PLSR is suitable for the soil salinity mapping, especially in semi-arid regions like Jaffna Peninsula. The results underpin the importance of building adaptive capacity and implementing suitable preventive strategies for sustainable land and agricultural management.