Abstract : This paper, starting from the outdoor water supply design code, mainly analyzes the contradiction between the actual operating conditions of water intake pumping stations drawing water from rivers and the design code, and proposes a solution using variable frequency speed regulation to achieve both the economic efficiency of actual operation and the reliability required by the code. Keywords : Variable frequency drive, environmental protection, purification 1 Introduction According to the GBJ13-86 outdoor water supply design code, the pump selection design of water intake pumping stations should consider the minimum raw water level to achieve a supply and demand guarantee rate of 90-99% and the maximum output of the pumping station. However, due to natural laws, the dry season for rivers in China is from December to March, when the river water level is at its lowest. The required static head of the pump is high, and the water supply of the pumping station is small, as shown in point A of Figures 1 and 2. During the peak summer water supply period from July to September, the river water level rises due to the arrival of the high-water season. Although the water supply of the pumping station increases slightly, the static head of the pump decreases, as shown in point B of Figures 1 and 2. The outdoor water supply design specifications rely on two factors: maximum water supply volume and minimum water level. These factors exhibit significant seasonal variations, and the probability of both occurring simultaneously is very low. Blindly following these specifications in the design of water intake pumping stations would lead to unreasonable selection of head and flow parameters, resulting in a significant discrepancy between the actual operating conditions and design parameters for most of the time, and substantial waste of energy and infrastructure investment. However, if only the water level and volume variations of normal years are considered without adhering to the specifications, and drought occurs during the summer peak water supply period, causing river levels to drop to their lowest point while the maximum water supply is required; or during the winter dry season, due to some special circumstances requiring the maximum water supply (as shown at point C in Figures 1 and 2), then the heavily invested water intake pumping station will not function as intended. 2. Water Level and Volume Variations and Existing Problems Taking the Yangtze River water level variation in the Nanjing area as an example, the average high water level during the summer high-water season is 9.50m (Wusong elevation, the same below). The average low water level during the winter dry season is 2.50m, while the design-considered extreme low water level of 1.42m is almost impossible to achieve. The peak water supply periods are July, August, and September, when river levels are high. Water demand is relatively low during the low water months of December, January, February, and March. [b][align=center]For more details, please click: A Discussion on Pump Selection and Speed ​​Regulation Design for Water Intake Pumping Stations[/align][/b]