Based on Tibet Laluo Hydroproject and Irrigation Project,some methods in common use are adopted to calculate the eco-environment water demand and contrast with the discharged flow which the project study out.

This paper studies the effect of Yongqing re -regulating reservoir on the waterquality of lower reaches of Jilin section by analyzing the changes of carrying capacity and water quality atdifferent discharges,and proposes the minimum discharge of Yongqing re-regulating reservoir by takingaccount.