selected directions. The X-shift generally shows an
eastward shifting over a total distance of 29,380 m.
The decreasing eastward shift shows that the
increment of channel length is slowing down. The Y-
shift generally displays a southward migration, with
a total shifting distance of 13,441 m. It exhibits a
dwindling southward shift. As a whole, however, the
outlet displacement generally tends to increase its
migrating distance.
| 20641781
Table 1 Statistics of river outlet migrating | / |
; i COASTUNE CHANGE OVER TIME () i
change over time. (une, 878 - Nov. 1981) / t
20714881 |
pM med
[Ne] Time Outlet Outlet shift Outlet i ER | N
displacement(m) X-shift | Y-shift | azimuth(’) | EE 2 eam ih:
1 | 06-02-76 reference point 95 : S Qr. 3308
7 112-1776 8645 8350 | -2240 83 x a
3 | 05-10-77 2961 2380 | 1761 98 | x E M EA
- - : THe EL FF... Tes BOHAI
4 | 10-05-78 12173 -6470 | 10311 62 | x} pu re M
i | = Séwgeg. 7 TIU C SES x Te
5 [06-30-81 12474 4550 |-11615 61 RTS vœu anal gm
6 | 11-21-81 7439 7310 | 1379 76 | Edi T aunt m.
f E EM 7 "s 7
7 | 10-05-84 11241 6390 | -9248 115 | S va Te
8 [04-18-86 10986 -9520 | -5482 184 = y dice E od
9 [11-19-86 2445 410 | 2410 178 Ç / nu
10 | 06-08-87 3924 3910 | 327 192 |. OOASTUME CHANGE OVER TIME (1) d LAZHOU Gu
11 | 11-17-88 6946 6910 | -705 115 Pm : ; NM.
12 | 03-09-89 1597 -1580 | 230 129 :
13 | 04-10-89 1354 740 | -1134 115 e EL A =
14 | 11-20-89 3064 2640 | -1556 135 du
15 | 03-12-90 3148 -40 | -3148 165 |
16 | 04-02-92 9147 -2510 | 8796 65 |
17| 11-12-92 9046 -290 | -9041 137 sig” rc md
18 | 05-23-93 5860 840 | 5799 MZ me ; nie Xo m
19 | 11-23-93 4356 3210 | -2944 123 mie ue iN
20 | 04-24-94 8643 -7630 | -4061 195 Rm à cie Inch a dr Aha
21107-24-94 11867 9780 | 6722 102 idi (X he vs T
i OE NA
For non-single river outlets, we choose the outlet of the dominant | 4 TIU
channel. =
COASTLINE CHANGE OVER TIME (ui) | CAT RA $
The coastline is carefully mapped from about 12 EE AL HAN bas em
selected images, based on a number of rules (Yang,
1995). The layouts are illustrated in Figure 3. The
deltaic area and the coastline length generally tend to
increase. The deltaic area increased at average of 22
km? per year for the period of June 1976 - April 24,
1994. However, the increment of deltaic area tends
to decrease. For the stage of June 1976 - Nov.,
1981, the yearly increment averaged 36 km?. It was
the most important delta-developing stage. During
the stage of Nov. 11, 1981 - Nov., 1988, the average
increment amounted to 27 km? per year. While after
1988 (till April 1994), the deltaic area increased at
an average of 2 km? per year. The deltaic lobe
showed an accelerating migration (Figure 3III).
Figure 3(I-III) ^ Coastline change over time.
5. DISCUSSION
This sector intends to provide a general discussion on
the factors controlling the deltaic morphology and its
change. Those factors include aspects of hydrologic,
marine hydraulic, geomorphological, geological,
climatical, vegetation and land use, and human
activities. Since most of those are not well
understood, we do not intend to discuss them further.
Instead, several selected problems are presently
focused on.
805
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B7. Vienna 1996
