We found that water quality in Lahan Swamp was in class 2 (good) according to the surface water
quality standards of Thailand. It was suitable for consumption with some special water treatment
processes before used; fishery, swimming and water sport were also acceptable in this area. Thus we
demonstrate that Lahan Swamp is more satisfactory class than other lake in the area, such as, Bueng
Thung Sang [6] and East Si-Tan Lake [7] where were class 2 of the surface water quality standard in
Thailand. However, high salinity and conductivity were found in summer because of salt rock [2]. On the
other hand, the high turbidity and coliform bacteria were found in the rainy season likely from erosion
and pathogen contamination from the outer to inner swamp. Furthermore, a detention project has now
commenced in the area [8]. Therefore, salinity, conductivity, turbidity and coliform bacteria will likely be
influenced, precautions should be taken. Moreover, BOD from dead plants especially algae and wate