A cost-effective river water monitoring method is vital when assessing the level of river health. In order to reduce the
monitoring burden as much as possible under the condition that the quality status of water bodies was evaluated fully
and accurately, the necessary monitoring indicators of Liaohe River and Xiangjiang River as well as their
mainstreams and tributaries were selected according to exceeding standard rates and pollution contribute rates of
indicators in this study. The water quality assessment results for the mainstreams of the above two rivers by using
selected indicators were compared with that by using all indicators without selection. Compared with all indicators,
the selected indicators are greatly reduced in number.