Characteristic and engineering impact of hydrodynamics and sediment transport

Survey results of marine current

Survey results of marine current in summer

Marine current observation data of four stations during spring tide in August 2010 are shown in Figures 7.3 through 7.6; marine current observation

Current velocity and direction change curve of Cl station

FIGURE 7.3: Current velocity and direction change curve of Cl station

during spring tide in August 2010

Current velocity and direction change curve of C2 station during spring tide in August 2010

FIGURE 7.4: Current velocity and direction change curve of C2 station during spring tide in August 2010

data of four stations during neap tide in August 2010 are shown in Figures

  • 7.7 through 7.10. See Section 7.2.1.3 for marine current analysis of various stations.
  • 1) Spring tide in summer
  • 2) Neap tide in summer

Survey results of marine current in winter

Marine current observation data of the four stations during spring tide in November 2010 are shown in Figures 7.11 through 7.14; marine current observation data of the four stations during neap tide in November 2010 are shown in Figures 7.15 through 7.18. See Section 7.2.1.3 for analysis for main marine current characteristic of various stations.

  • 1) Spring tide in winter
  • 2) Neap tide in winter
Current velocity and direction change curve of C3 station during spring tide in August 2010

FIGURE 7.5: Current velocity and direction change curve of C3 station during spring tide in August 2010

Summary

Table 7.4 provides the tidal current value of different stations in the four surveys; according to the table:

1) During spring tide in November:

Mean and maximum current velocities of Cl station in the vertical direction are 30.3 cm/s and 60 cm/s;

Mean and maximum current velocities of C2 station in the vertical direction are 16.9 cm/s and 52.7 cm/s;

Mean and maximum current velocities of C3 station in the vertical direction are 14.1 cm/s and 51.8 cm/s;

Mean and maximum current velocities of C4 station in the vertical direction are 15.5 cm/s and 49.3 cm/s; current velocity gradually decreases from the outside to the inside of the investigated sea area; mean current velocity in the investigated sea area during the survey period is 23.1 cm/s.

Current velocity and direction change curve of C4 station during spring tide in August 2010

FIGURE 7.6: Current velocity and direction change curve of C4 station during spring tide in August 2010

2) During neap tide in November:

Mean and maximum current velocities of Cl station in the vertical direction are 28 cm/s and 54 cm/s;

Mean and maximum current velocities of C2 station in the vertical direction are 21.3 cm/s and 44.4 cm/s;

Mean and maximum current velocities of C3 station in the vertical direction are 18.8 cm/s and 47.1 cm/s;

Mean and maximum current velocities of C4 station in the vertical direction are 16.4 cm/s and 40.2 cm/s; current speed gradually decreases from the outside to the inside of the investigated sea area; mean current velocity in the investigated sea area during the survey period is 23.6 cm/s.

3) During spring tide in August :

Mean and maximum current velocities of Cl station in the vertical direction are 29.7 cm/s and 75.9 cm/s;

Current velocity and direction change curve of Cl station during neap tide in August 2010)

FIGURE 7.7: Current velocity and direction change curve of Cl station during neap tide in August 2010)

Mean and maximum current velocities of C2 station in the vertical direction are 14.1 cm/s and 57.8 cm/s;

Mean and maximum current velocities of C3 station in the vertical direction are 21.1 cm/s and 49.8 cm/s;

Mean and maximum current velocities of C4 station in the vertical direction are 19.2 cm/s and 53 cm/s;

Current velocity gradually decreases from the outside to the inside of the investigated sea area; mean current velocity in the investigated sea area during the survey period is 29 cm/s.

4) During neap tide in August:

Mean and maximum current velocities of Cl station in the vertical direction are 28.7 cm/s and 67.4 cm/s;

Mean and maximum current velocities of C2 station in the vertical direction are 23.8 cm/s and 51.3 cm/s;

Current velocity and direction change curve of C2 station during neap tide in August 2010)

FIGURE 7.8: Current velocity and direction change curve of C2 station during neap tide in August 2010)

Mean and maximum current velocities of C3 station in the vertical direction are 22.9 cm/s and 44 cm/s;

Mean and maximum current velocities of C4 station in the vertical direction are 15.8 cm/s and 38 cm/s;

Current velocity gradually decreases from the outside to the inside of the investigated sea area; mean current velocity in the investigated sea area during the survey period is 26.4 cm/s. Current velocity distribution characteristics in the investigated sea area: the current velocity decreases gradually from stations Cl to C4.

Change of current velocity with season: the current velocity is high in August; during which month the maximum and mean current velocities are

75.9 cm/s and 27.7 cm/s; the current velocity is low in November, during which month the maximum and mean current velocities are 60 cm/s and 23.4 cm/s.

Current velocity and direction change curve of C3 station during neap tide in August 2010

FIGURE 7.9: Current velocity and direction change curve of C3 station during neap tide in August 2010

Survey results of suspended sediment concentration

Results in summer

Suspended sediment concentration change curves at four stations during spring tide in August 2010 are shown in Figures 7.19 through 7.22; suspended sediment concentration change curves at four stations during neap tide in August 2010 are shown in Figures 7.23 through 7.26. See Section 7.2.2.3 for suspended sediment concentration values of various stations.

  • 1) Spring tide in summer
  • 2) Neap tide in summer

Results in winter

Suspended sediment concentration change curves at four stations during spring tide in November 2011 are shown in Figures 7.27 through 7.30;

Current velocity and direction change curve of C4 station during neap tide in August 2010

FIGURE 7.10: Current velocity and direction change curve of C4 station during neap tide in August 2010

suspended sediment concentration change curves at four stations during neap tide in November 2010 are shown in Figures 7.31 through 7.34. See Section

  • 7.2.2.3 for suspended sediment concentration values of various stations.
  • 1) Spring tide in winter
  • 2) Neap tide in winter

Summary

Table 7.5 provides suspended sediment concentration at four stations during different survey periods and main characteristics of them are as follows: 1) During spring tide in November:

Suspended sediment concentration of Cl station changes between 5.4 and

23.7 mg/1; mean suspended sediment concentration of various layers ranges from 10.6 to 16.7 mg/1; mean suspended sediment concentration in this measurement is 12.9 mg/1;

Current velocity and direction change curve of Cl station during spring tide in August 2010

FIGURE 7.11: Current velocity and direction change curve of Cl station during spring tide in August 2010

Suspended sediment concentration of C2 station changes between 5.4 and

20.6 mg/1; mean suspended sediment concentration of various layers ranges from 8.8 to 13.6 mg/1; mean suspended sediment concentration in this measurement is 10.7 mg/1;

Suspended sediment concentration of C3 station changes between 7.6 and

24.8 mg/1; mean suspended sediment concentration of various layers ranges from 10 to 16.8 mg/1; mean suspended sediment concentration in this measurement is 12.8 mg/1;

Suspended sediment concentration of C4 station changes between 4.2 and

25.6 mg/1; mean suspended sediment concentration of various layers ranges from 8.5 to 14.4 mg/1; mean suspended sediment concentration in this measurement is 11.1 mg/1;

Suspended sediment concentration of various stations during spring tide in November ranges from 4.2 to 25.6 mg/1; mean suspended sediment concentration at four stations is 11.9 mg/1.

Current velocity and direction change curve of C2 station during spring tide in August 2010

FIGURE 7.12: Current velocity and direction change curve of C2 station during spring tide in August 2010

During neap tide in November:

Suspended sediment concentration of Cl station changes between 9.2 and

33.8 mg/1; mean suspended sediment concentration of various layers ranges from 18.2 to 25.7 rng/l; mean suspended sediment concentration in this measurement is 21.1 mg/1;

Suspended sediment concentration of C2 station changes between 6.8 and

36.4 mg/1; mean suspended sediment concentration of various layers ranges from 11.9 to 22 mg/1; mean suspended sediment concentration in this measurement is 16.2 mg/1;

Suspended sediment concentration of C3 station changes between 7.0 and

28.2 mg/1; mean suspended sediment concentration of various layers ranges from 10 to 16.8 mg/1; mean suspended sediment concentration in this measurement is 14.8 mg/1;

Suspended sediment concentration of C4 station changes between 7.4 and

23.2 mg/1; mean suspended sediment concentration of various layers ranges

Current velocity and direction change curve of C3 station during spring tide in August 2010

FIGURE 7.13: Current velocity and direction change curve of C3 station during spring tide in August 2010

from 10 to 14.7 mg/1; mean suspended sediment concentration in this measurement is 11.7 mg/1;

Suspended sediment concentration of Cl to C4 stations gradually increases from inside to outside during neap tide in November. Suspended sediment concentration of various stations ranges from 6.8 to 36.4 mg/1; mean suspended sediment concentration at four stations is 15.9 mg/1.

3) During spring tide in August :

Suspended sediment concentration of Cl station changes between 4.6 and 48 mg/1; mean suspended sediment concentration of various layers ranges from

10.3 to 25.9 mg/1; mean suspended sediment concentration in this measurement is 17 mg/1;

Suspended sediment concentration of C2 station changes between 4.4 and

60.2 mg/1; mean suspended sediment concentration of various layers ranges from 10.8 to 35.1 mg/1; mean suspended sediment concentration in this measurement is 21.6 mg/1;

Current velocity and direction change curve of C4 station during spring tide in August 2010

FIGURE 7.14: Current velocity and direction change curve of C4 station during spring tide in August 2010

Suspended sediment concentration of C3 station changes between 8.0 and

89.8 mg/1; mean suspended sediment concentration of various layers ranges from 19.4 to 61.7 mg/1; mean suspended sediment concentration in this measurement is 38.9 mg/1;

Suspended sediment concentration of C4 station changes between 5.0 and

91.8 mg/1; mean suspended sediment concentration of various layers ranges from 18.7 to 45.7 mg/1; mean suspended sediment concentration in this measurement is 28.2 mg/1;

The investigated sea area has a high suspended sediment concentration which gradually increases from inside to outside (Cl to C3 stations) during spring tide in August. Suspended sediment concentration of various stations ranges widely from 4.4 to 91.8 mg/1; mean suspended sediment concentration of the investigated sea area is 26.4 mg/1.

Current velocity and direction change curve of Cl station during neap tide in August 2010

FIGURE 7.15: Current velocity and direction change curve of Cl station during neap tide in August 2010

4) During neap tide in August:

Suspended sediment concentration of Cl station changes between 2.6 and 30 mg/1; mean suspended sediment concentration of various layers ranges from 8 to 18.9 mg/1; mean suspended sediment concentration in this measurement is 13.5 mg/1;

Suspended sediment concentration of C2 station changes between 2 and

32.4 mg/1; mean suspended sediment concentration of various layers ranges from 5.9 to 17.2 mg/1; mean suspended sediment concentration in this measurement is 10.5 mg/1;

Suspended sediment concentration of C3 station changes between 4.2 and

40.8 mg/1; mean suspended sediment concentration of various layers ranges from 10 to 23.3 mg/1; mean suspended sediment concentration in this measurement is 14.1 mg/1;

Suspended sediment concentration of C4 station changes between 2.4 and

46.4 mg/1; mean suspended sediment concentration of various layers ranges

Current velocity and direction change curve of C2 station during neap tide in August 2010

FIGURE 7.16: Current velocity and direction change curve of C2 station during neap tide in August 2010

from 12.1 to 27.4 rng/1; mean suspended sediment concentration in this measurement is 18.5 mg/1;

Suspended sediment concentration of various stations during neap tide in August ranges from 2.0 to 46.6 mg/1; mean suspended sediment concentration of the investigated sea area is 14.1 mg/1.

 
Source
< Prev   CONTENTS   Source   Next >