Evaluation of Eutrophication State of Mae Kuang Reservoir, Chiang Mai, Thailand by Using Carlson’s Trophic State Index

Abstract

Eutrophication is an event that occurred when the lakes have a high growth rate of phytoplankton and causing deterioration of water quality. In this work, we use Carlson’s Trophic State Index (CTSI) to evaluate the situation of eutrophication of Mae Kuang Reservoir for the first time. Three parameters, i.e., total phosphorus, chlorophyll-a, and water transparency were used to calculate CTSI. The results showed that the reservoir has started to be eutrophic. In June and October, the ranges of the CTSI were 49.26–59.60 and 49.07–56.04, respectively, which indicated a low eutrophic state of the reservoir. However, in this primary eutrophic condition, the water quality was not bad, and the living organisms can survive. The CTSI is a valuable and simple alternative method for monitoring and estimating lake ecosystems' eutrophic status.