Browsing by Author "Balendran, S."

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    Investigation of the Effectiveness of Salt Barrage in Jaffna Peninsula
    (Uva Wellassa University of Sri Lanka, 2012) Balendran, S.
    To convert the internal salt water lagoon Upparu, to fresh water lake is expected to improve the water resources of the peninsula, both in recharging the underground storage with additional surface storage and desalinating the lands fringing the lagoons and making suitable for cultivation (K. Shanmugarajah, 1993) and fresh water prawn farming in the banks of the lagoon. Repair and replacement of these barrages were finished in the month of October 2009. This research focus on the area from the fringe of the lagoon into the land extending for 2 km perpendicularly to evaluate the effectiveness of the barrage by delineating the salt water intrusion pattern and ground water flow pattern. Wells were selected in a profile perpendicular to the fringe of Uppu Aru and Jaffna lagoon. The areas coming under study are parts of Nallur, Kopay and Chavakachcheri D.S Divisions. Electrical conductivity (EC) values and water level were measured in situ for groundwater samples which were drawn from 97 wells in each month of January and July. Thirty shallow well samples were selected for chemical analysis out of 97 wells in which EC was measured. Water samples were analysed to determine Chloride and Sodium. EC values for groundwater in the study areas vary between 324 µS/cm and 16,550 µS/cm in wet seasons between 614 µS/cm and 19,310 µS/cm in dry seasons. Chloride values vary in between 0.71mg/L and 8165 mg/L in wet seasons between 42 mg/L and 4356 mg/L in dry seasons. Sodium values vary in between 20 mg/L and 8492 mg/L in wet seasons and between 116 mg/L and 4021 mg/L in dry seasons. Groundwater in the fringe of the Upparu lagoon which is far from the barrage is having good quality water than the groundwater close to the barrage in both seasons. If the barrage works properly the groundwater in the fringe of the lagoon will become as fresh water in near future. Therefore, it can be concluded the effectiveness is less during both seasons. However, further continuation of this research would deliver a much better result.
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    Investigation of the Effectiveness of Salt Barrages in Jaffna Peninsula
    (Uva Wellassa University of Sri Lanka, 2012) Balendran, S.; Udagedara, D.T.; Attanayake, A.N.B.
    The Jaffna Peninsula which is the northernmost tip of Sri Lanka has its groundwater source in the subsurface limestone layer. Due to over exploitation of groundwater for agricultural needs, most wells in the region have become brackish. Therefore, a supply source to replenish the wells to meet the increasing demand for fresh water is of paramount importance. Converting the two internal saltwater lagoons, Vadamarachchi and Upparu, to fresh water lakes is expected to improve the water resources of the peninsula, both in recharging the underground storage with additional surface storage and desalinating the lands fringing the lagoons. Making these lands suitable for cultivation and fresh water prawn farming in the banks of the lagoon are also expected (Shanmugarajah, 1993). The Upparu lagoon with surface area of about 26 km2 has opening to the sea towards the south and is mainly a saltwater lagoon. During the north-east monsoon rain water fills up the lagoon lowering its salinity. Saltwater barrages have been erected in the mid-1900s to convert the lagoon into a fresh water lake (Rajasooriyar et.al., 2002). However, the barrages have not functioned properly and have allowed the salt water to intrude. Repair and replacement of these barrages were completed in October 2009. Currently the effectiveness and the efficiency of the Ariyalai barrage of Upparru lagoon is monitored by the Irrigation Department by observing the salinity of surface water in five locations every month. This research focuses on evaluating the effectiveness of the Ariyalai barrage by delineating the saltwater intrusion pattern and groundwater flow pattern within the area extending from the fringe of the lagoon into the land for 2 km. The larger area coverage is expected to provide a more realistic picture of the saltwater intrusion patterns and hence a correct assessment of the effectiveness of the barrages.