Saline Water Movement In The Estuary Of The Nakdong River

낙동강 하구의 염수운동

  • Published : 1981.06.01


Saline water movements in relation to tidal condition and river discharge in the estuary of the Nakdong River are discussed on the basis of the observation data. The difference of salinity between the surface and the bottom layer was 1∼3 at spring tide forming a vertically homogeneous estuary, while at neap tide, it ranges up to 7∼15 indicating a sharp salt wedge. The maximum salinity appeared approximately at an hour after the high water, that is, three hours after the landward velocity maximum, while the salinity maximum at around an hour after the low water, that is, three hours after the seaward velocity maximum. The density current speed at a section located 10km landward from the river mouth was observed approximately to be 45cm sec$\^$-1/ at 8m layer.The relations between the salinity at Gupo and the river discharge at Jindong are estimated by means of the least square method. The maximum length of the salt wedge is calculated approximately to be 22km at neap tide and 16km at spring tide, which is in accordance with the observed data. The salinity influence area is deduced to be 45km at spring tide and 35km at neap tide. The diffusion coefficient of salinity was estimated approximately to be 1.5 10$\^$8/$\textrm{cm}^2$ sec$\^$-1/ at Samrak and 8 10$\^$5/$\textrm{cm}^2$ sec$\^$-1/ at Gupo at neap tide, while it was 1.4 10$\^$7/$\textrm{cm}^2$ sec$\^$-1/ at Dongwon at spring tide.