Variation of Salinity in Batticaloa Lagoon in Sri Lanka during Wet Season

Abstract

Batticaloa lagoon occupies an area of 168 km 2 in the eastern coast of Sri Lanka. Change in lagoon water salinity is an important aspect that affects the availability and composition of aquatic resources and the livelihoods of the people who are depending on these resources. In this view, lagoon water level, electrical conductivity (EC), salinity, pH and temperature were continuously monitored at two locations, namely Kallady and Manmunaithurai, which are located 7.5 km apart. Readings were taken at weekly intervals during the wet season between September 2012 to March 2013. The lagoon water levels varied between 0.01 and 1.32 m above mean sea level (AMSL) at Kallady, which is located near the barmouth, whereas the variation at Manmunalthurai was between 0.15 and 1.54 m. Corresponding salinity variation was from 37.5 to 3.5 ppt and 31.0 to 4.5 ppt at Kallady and Manmunaithurai, respectively. Surface water temperature at these two locations varied between 25.1 o C to 30.6 o C and the pH varied between a narrow range of 7.7 and 8.7. Salinity showed a highly significant decreasing trend with time (r=-0.693 and-0.71, p<0.01 at Kallady and Manmunai area, respectively) during the rainy season. Similarly, a significant positive correlation was observed between the rainfall amount and the lagoon water height (r=0.782 and r=0.853, p<0.01 at Kallady and Manmunai area, respectively). However, salinity showed no significant correlation with lagoon water height and the amount of rainfall. This may be due to the influence of tidal action on lagoon water salinity. The study revealed that a substantial variation in salinity occurs during a short period during the wet season and warrants further investigation on its influence on ecosystem and livelihoods.

Spatial and temporal dynamics of water quality in Batticaloa lagoon in Sri Lanka

“…However, it could affect the paddy cultivation near the lagoon. As far as the relationship between salinity of the Batticaloa Lagoon and rainfall amount is concerned, Sugirtharan et al, (2014a) reported that, salinity showed a highly significant decreasing trend with time (r=-0.693) during the rainy season whereas, non-significant negative correlation was found between rainfall amount and the salinity during dry season (2014b). Similarly, a significant positive correlation was observed between the rainfall amount and the lagoon water height (r=0.782).…”

An Ecological Risk Assessment of Sediments in a Developing Environment—Batticaloa Lagoon, Sri Lanka

“…This lagoon is located in eastern coast of Sri Lanka and exposed to the Bay of Bengal. The depth of the shallow areas is about 0.3 m, whereas in lagoon mouth regions it is recorded as 6.5 m [20]. The southern zones of the lagoon are freshwater dominant whereas northern zones are salt-water dominant [21].…”

“…Batticaloa is the third largest lagoon of Sri Lanka with a surface area of 168 km 2 [20]. This lagoon is located in eastern coast of Sri Lanka and exposed to the Bay of Bengal.…”

Climate change awareness and perception among the community residing nearby areas of Batticaloa lagoon in Sri Lanka

“…However, 10.7% of the respondents mentioned that, there are no any considerable changes in the total amount of rainfall during the season but they observed the increased rainfall intensity that leads to the fast flood in Batticaloa. Sugirtharan et al (2014) also reported that, the heavy rain (total amount of rainfall was 330.9 mm) occurred during 15.12.2012 to 18.12.2012, the lagoon water entered the adjacent land upto 30-48 m from the lagoon border. At the time of this event, adjacent roads (Lady manning road, Lake Road etc) and portion of the land area of the households near lagoon were flooded and disturbed the livelihood activities.…”