Time Scale Variation of Some Selected General Water Quality Parameters of Batticaloa Lagoon, Sri Lanka

Abstract

The present study was conducted to find out the time scale variation of some water quality parameters of the Batticaloa Lagoon in Sri Lanka from January 2019 to April 2019. Ten sampling locations in the middle part of the lagoon were selected. Nowadays the quality of lagoon water is reducing due to natural and anthropogenic activities such as flooding, dumping garbage at coastal area, drain the household outlet towards the lagoon, washing animals such as cattle and buffalo near the coastal area, washing fishing equipment inside the lagoon and releasing chemicals from farm land and due to the natural disasters. However, no information available on time scale variation of physico-chemical parameters in the lagoon water throughout the day. Therefore, characterizing spatial and temporal dynamics of water quality in terms of physico-chemical parameters of the lagoon is an important finding to formulate the management plan against its effect on dependent economic activities for instance fishing, tourism, irrigation and aquaculture industry such as prawn farming and crab culture. The water quality parameters were analysed within a day at different time intervals to identify the relationship between the temperature and other water quality parameters in the study area. Water quality parameters such as temperature, Electrical Conductivity (EC), Total Dissolved Solids (TDS), pH, Dissolved Oxygen (DO) and Turbidity were measured at 15-30 cm below the water surface from different locations of the lagoon from morning 6.00 am to evening 6.00 pm daily. High values of EC and TDS were recorded in the lagoon water near the bar mouth. The temperature of the water depends on atmospheric temperature by the time at which sample was taken. The temperature of the lagoon in some areas may also depend on atmospheric temperature, external surrounding factors such as concrete pavement and discharges from surroundings etc. There was no significant variation of EC, TDS and turbidity observed with time during the day. As far as the pH is concerned, the sampling locations, far away from the bar mouth area showed comparatively low pH values. Further, the findings of this study will be considered as baseline information about the time scale variation of water quality and essential tool for future researchers in the Batticaloa lagoon management.