In recent years

the Three Gorges reservoir has implemented drought-relief water replenishing operation several times in emergency response to drought events in the middle and lower Yangtze River. However

it is not yet clear how an increase in the discharge replenishment influences the water levels at the main cross sections downstream of the reservoir

and an index system has not been established yet for evaluating the drought-relief water replenishment benefits of a reservoir. This paper develops a water level simulation model for a river section based on long short-term memory neural networks

and simulates the time variations in water level at the typical sections of the study reaches. And an index system for the reservoir’s benefits evaluation is constructed considering comprehensively water supply

ecology

shipping

and power generation. The results show that under the reservoir’s three replenishing schemes of 500

1000

and 2000 m3/s in August

2022

the water level and discharge at the main control stations in the study reaches would be able to rise to a certain extent. The restored irrigation area would be 2.9 thousand ha

and the economic benefit of agricultural irrigation be 13.55 million yuan. The increased power generation benefits would be 14.00

27.25

and 32.25 million yuan under the three schemes

respectively. The ecological and shipping benefits would not change considerably

because of only a small increase in water level and discharge. This study helps formulate drought-relief water replenishing plans for the Three Gorges reservoir.