The effect of cascade hydropower group's leading reservoir regulation
control on nitrogen migration
Abstract
Cascade hydropower group of Wujiang River in Guizhou Province, China, is
an essential part of the west-east power transmission project. Hongjiadu
Hydropower Station is the first reservoir in the cascade hydropower
group, with a hydraulic retention time of 1.008 years, DAM height of
179.5 m, a controlled watershed area of 9,900 km2, a total storage
capacity of 4.95 billion m3, an adjusted storage capacity of 3.36
billion m3, an annual average runoff of 4.89 billion m3, a total
installed capacity of 0.6 million kilowatts[1]. Since 2004,
Hongjiangdu Hydropower Station has generated power. Water storage in the
flood period and water power generation in the dry period led to a huge
difference in water level and affected fish habitat. Firstly, the water
and nitrogen mass balance model was applied. CVL Grid and Google Earth
Pro were applied to build 292 orthogonal grids. Environmental fluid
dynamics code was exploited to simulate the hydrodynamic, temperature,
water quality, and sediment modules of Hongjiadu Reservoir in 2007, 2008
and 2017. The fieldwork and the interpolation method were used the
inputted particulate refractory organic nitrogen, easily degradable
organic nitrogen, dissolved organic nitrogen, Kjeldahl nitrogen, ammonia
nitrogen[2,3], nitrate-nitrogen[2,3], and total nitrogen of
inflow rivers. Cage farming brought large amounts of particulate
nitrogen (fish feed), which were input the corresponding grids of
Hongjiadu Reservoir. Fortunately, cage farming has now turned into
ecological fish farming. This model was an exploration of fish habitat
protection in the first stage of a cascade hydropower station.
[1]Liang, X.; et. al. 2019. Control of the hydraulic load on nitrous
oxide emissions from cascade reservoirs. Environ. Sci. & Technol.
53(20): 11745-11754. [2]Liu, X. 2010. The effects of cascade
reservoirs on biogeochemical cycling of nitrogen in River-Reservoir
system -take Wujiang River and its branch Maotiao River in SW China for
example, Guiyang, Institute of Geochemistry, Chinese Academy of
Sciences, Doctoral degre (In Chinese).