Fengman Dam

The Fengman Dam is a concrete gravity dam from Jilin City on the Second Songhua River in Jilin Province, China. The main purposes of the dam are hydroelectric power generation and flood control. Construction of the dam began in 1937 and was complete in 1953. The dam is owned and operated by Northeast China Grid Company Limited. 
A new dam was completed in 2019, and the old dam will be dismantled, except for a small section preserved for historical interest .
History.
Construction on the Fengman Dam began in 1937 under the Japanese during their occupation of parts of China during World War II. In November 1942, the reservoir behind the dam began to fill and by March 1943, the first generators were operational. Still lacking floodgates, the dam was not entirely complete after the Japanese occupation in 1953. In 1959, the eighth and final generator of the first stage was installed, bringing the power station's installed capacity to 552.5 MW. Between 1970 and 1979, a tunnel was installed on the left bank of the dam and it was later converted into a flood discharge tunnel in 1991. In 1988, the second stage of construction began which included the installation of a ninth and tenth turbine. This was complete in 1992 and the plant's total installed capacity was 722.5 MW. From 1993 to 1998, the third stage of constructed on the dam was carried out, bringing the power station to a final installed capacity of 1002.5 MW.
Reservoir.
The Fengman Reservoir, also known as Songhua Lake, has a capacity of of which is active or "useful" storage and is used for flooding. The reservoir is narrow, long, and has a surface area of . Normal reservoir level is above sea level, minimum is and a maximum of . The drainage or catchment area is of which is controlled by the Baishan Dam, is located within the Daogou area and is controlled by the Hongshi Dam. Annual rainfall in the reservoir zone is - with 60-90 percent falling between July and September each year. Average mean runoff is , maximum mean is while the minimum mean is . Maximum instantaneous runoff during flooding can reach while during ice season, it can be as low as .
Design.
The Fengman dam is a high and long concrete gravity dam which is divided into 60 sections. Sections 1-8, 20 and 32-60 are non-overflow while 9-19 contain the 11 crest overflow spillways. Sections 21-31 contain the ten intakes and penstocks for the power plant which rest at their base, the dam's toe. The dam's crest spillway has a capacity while the long, diameter flood discharge tunnel on the left bank has a capacity.
New Dam.
A new dam was constructed 120m downstream of the old dam, during the period 2015-2019 
The new dam is 50% higher than the old one, and has 50% more electrical generation capacity. As the last of the new turbines was installed in 2019, work started on dismantling the old dam. 