SGD in Huang River estuary

(Xu et al. , 2013)conducted a study using 223Ra,224Ra and 226Ra. He calculated that the SGD flux was 1.3*109m3/d, and the range of variation was 2.8*108 to 3.0*109m3/d. Moreover, he believed that the SGD flux had little impact on sediment generation. (Taniguchiet al. , 2008)mainly investigated SFGD with an automatic percolation apparatus. In September 2004 and September 2006, the SFGD of the whole delta was about 110 and 170m3/s, respectively. These freshwater flows are equivalent to 4.5 to 7.0 per cent of the Yellow River’s flow over the same period. Both scholars noticed the migration of SGD region.
In 2014, (Xu et al. , 2014) first studied the impact of Water Sediment Regulation Scheme (WSRS) on SGD. They used the field measurements from 222Rn and 220Rn to determine the possible SGD location of the Yellow River estuary and concluded that high river flow (>3000 m3/s) may be necessary for a large amount of fresh SGD in the system. They also observed that during the WSRS, FSGD resulted in a unique vertical profile of the benthic boundary layer, with a decrease in all salinity, dissolved oxygen, and turbidity. Futher more, they built a positive correlation between nutrient content and222Rn, indicating that SGD is the main nutrient route in the estuary of the Yellow River.
(Xia et al. , 2016) integrated other hydrological parameters in space and time for radium and radon isotopes during the non-WSRS and WSRS in 2013. By comparing the data, it can be seen that the radium (223Ra, 224Ra,226Ra) and 222Rn activities in the Yellow River estuary during the WSRS period are significantly higher than those in the non-WSRS period. This different distribution may predict the changes of fluid dynamics and SGD flux. The artificial flooding caused by WSRS accelerates the hydrodynamic process and increases the offshore transport rate. It is found that the SGD flux of the Yellow River estuary during WSRS is much larger than that during non-WSRS. During the WSRS, SGD was highest along the channel, and the composition of fresh SGD was conservatively estimated to account for about 24% of the total SGD.