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.