The dynamic Remote Sensing monitoring of the east four outlets in Pearl river estuary and its application on offshore engineering
Dynamic recent change analysis for the water sediment transport at the outlets
Remote Sensing images of one time phase can show the characteristics such as flow pattern of runoff and tidal current horizontal distribution of surface suspended sediment and its gradient change which can objectively indicate the interaction increase and decrease of various hydro dynamics under given conditions However comparing and analyzing the dynamics characteristics of multi-time-phase images the characteristics of the changes in water sediment transport with time and space and its dynamic mechanism can be revealed According to this analysis following are the main characteristics of dynamic recent change in water sediment transport at he east four outlets .
- It is found an arc shape inter line from the top of the Bay to the mouth exists on the images in the middle stage of flood tide and ebb tide both in medium flow and flood periods this line divides the Bay in to two parts the east part and the west part The west part is a water sediment transport zone dominated by the dynamics of runoff from Jiaomen, Hongqimen and Hengmen Outlets, while the east one dominated by the dynamics of tidal current passing through Humen Outlet. This remarkable inter line shown on the images is quite stable in horizontal location main training alignment in the west part of lingdingyang Bay in the improvement planning That is if the alignment is planned to the west of this inter line the tidal current dynamics in Lingdingyang Humen will not be severally affected.
Fig. 2 TM Image of Lingdingyang Bay in Flood Flow
and Flood Tide
(03 / 07 / 1988 )
- Recently, the water-sediment runoff coming easterly out from the North Branch of Jiaomen Channel has a large effect on the water sediment transport at Humen out let and in the east part of the Bay IN medium flow and periods the easterly flow coming from North Branch of Jaiomen C Channel severely impacts the tidal current at Humen Outlet in the middle stage of flood or ebb tide in the last stage of ebb tide as the tidal current in the east part of the Bay is considerably weakened the flow coming from the North Branch of Jioamen Chuanbi Channel into east part of the Bay (Fig. 3).
Fig. 3 Interpretation of Flow Field and Sediment Concentration
Lingdingyang Bay
(08 / 12 / 1987 )
- Due to the growth of the sand at Jiaomen outlet and the construction of the reclamation projects the sediments runoff coming through the North Branch transport recently less through the gully between the shoal southeasterly. The suspended sediment gathering zone fore casting due to the intersection of the flow going downstream from Jioamen outlet and the tidal current going upstream has recently been moved to the vicinity of the entrance shoal and the tail of Masha Shoal the easterly dominant flow resulting the combination of the flows from Hongqimen outlet and North Branch of Hengmen Channel does not go easterly across shoal In to the mouth of the South Branch of Jiaomen channel any longer but a part of them downward water- sediment flow goes in to the shaxia of lingding channel through the gully between the entrance shoal and the tail of Shaxianwei Shoal it will be harmful to lingding channel if developing naturally.
