Lake Water Quality Assessment Through GIS based Interpolation Method: A Case Study of Beris Dam, Kedah, Malaysia

Abstract

Preliminary research on physicochemical and water quality in the Beris dam shows that the water catchment area has the best standards and quality during the observation of the wet season and dry season mainly in the northern states of peninsular Malaysia. The analysis of water quality assessment using the DOE-WQI and Carlson Trophic State Index (CTSI) resulted that during the dry season (February), the average DOE-WQI reading is 88 or Class II; while during the wet season, the average DOE-WQI reading recorded 87.1 (October). Although the CTSI score was 34.2 - 27.0 during wet season and dry season, both seasons were classified as oligotrophic conditions. Some physicochemical parameters also show a high correlation between them and indicates minor water quality issues. The use of more efficient interpolation techniques in water quality studies also reinforces the evaluation of water quality. As a reference point for future water research, GIS interpolation application methods can be more effectively and efficiently used with Inverse Distance Weighted (IDW), Ordinary Kriging and Spline techniques. HIGHLIGHTS Investigation of physicochemical and water quality in lake water in Beris Dam Assessment by using water quality index by DOE-WQI and Carlson Trophic State Index (CTSI) to acknowledge water quality and trophic condition. Analyzing physicochemical data into mathematical method to compare between physicochemical data and correlate between them. Application of GIS based interpolation methods to analyze and referencing physicochemical data into spatial interpolation maps. Comparing appropriate spatial interpolation techniques to analyze physicochemical observation data and index. GRAPHICAL ABSTRACT