INVESTIGATION OF THE EFFECTIVENESS OF UPPARU SALT BARRAGE IN JAFFNA PENINSULA (3 Stage)
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Date
2015
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Uva Wellassa University of Sri Lanka
Abstract
The Jaffna Peninsula is located in the northern Sri Lanka. The total area of the Jaffna Peninsula is
and demarcated three internal lagoons such as Thondamanaru, Upparu and Valukiaru.
The first two lagoons comprise of an area of 77.6 km and 25.9 km . They are connected to the
sea and drain an area of 518 km . Majority of the local community of the area is depending on
agriculture and fishing.
Groundwater is the main source for people in Jaffna Peninsula for domestic and agricultural
activities. According to the field observations even people having their own wells, majority of
them are affected by salt water intrusions. Therefore, they depend on the common water supply
given by the government for drinking purposes, whereas some people still depend on groundwater
sources. Recently, barrage was constructed as a salt water exclusion bund to convert the salt water
in lagoon Upparu to fresh water lake. This is expected to improve available water resources of the
peninsula, both in recharging the underground storage (Sukanya, 2012). This research is focus of
the area from the fringe of the lagoon into the land extending around 2 km. Major aim of the
research is to evaluate the effectiveness of the barrage by delineating the salt water intrusion
pattern especially in the west and northwest areas of the lagoon.
Methodology
Existing aquifer types, geology and topography were studied with the help of available resources
and monitoring was done in the area. Wells were selected in a circle to the fringe of Upparu lagoon.
The areas coming under study are parts of Nallur, Kopay and Chavakachcheri divisional
secretariat divisions. Electrical conductivity (EC) of the groundwater was measured during wet
and dry seasons. The wells in which EC show a sudden change was selected for further chemical
analysis (sodium and chloride). In addition, both wet and dry season sixty eight (68) shallow well
samples were selected for sampling. Water samples were collected in PETF bottles, acidified and
capped tightly. Water samples were analyzed for Na using Varian Atomic Absorption
Spectrometer (AAS 240 series) facility available at the Uva Wellassa University. Chloride was
measured with argentometric method. Spatial distribution of the chemical & physical parameters
in the groundwater was interpolated using Inverse Distance Weighted method available in Arc
GIS 9.3 software.
Results and Discussion
Results of this study show that EC values for groundwater in the study areas varies between 574
µS/cm and 23,470 µS/cm in wet seasons and between 544 µS/cm and 22,810 µS/cm in dry
seasons. Element chloride values range between 449.8mg/L and 7,197.7 mg/L in wet seasons and
between 949.7 mg/L and 4,098.7 mg/L in dry seasons. Sodium values vary in between 38.3 mg/L
and 802.9 mg/L in wet seasons and between 26.7 mg/L and 648.4mg/L in dry seasons.
Description
Keywords
Mineral Sciences, Materials Sciences, Water Chemistry, Water Management, Water quality, Environmental Science, Biodiversity – Sri Lanka