RIASSUNTO
2D spatial interpolation method is commonly used to estimate unknown values in a specific location that are unmeasured in the observation process. Maninjau Lake is an important lake in West Sumatera, Indonesia, especially for the people in Agam District. The lake water has been utilized for irrigation, fisheries, farms, tourism and also generating the electricity. Water quality condition must be considered due to the social and economical aspects for the society. However, some of the anthropogenic activities and fish aquaculture lead to deterioration of the water quality. Since 1997, the lake suffered a catastrophic eutrophication by algal blooming of microcystys sp. Eutrophication in the Maninjau Lake caused taste and odor problems, oxygen depletion, and fish killed. Water quality parameters observed (""snap shot”) in this study are nutrients (Total Nitrogen and Total Phosphorus) and Chlorophyll-a content. Nitrogen and Phosphorus are chemical materials that stimulate alga growth, while Chlorophyll-a is used to determine phytoplankton biomass and to classify the tropic level of the lake. In this study, Inverse Distance Weighted (IDW) and Ordinary Krigging (OK) are compared. The result shows that OK with exponential function outperformed both OK with Gaussian function and IDW in all parameters.