Announcement on Large Floods in the
Mekong River Delta
(According to Bulletin No.198 /DBKTTV,
issued by the Hydro-meteorological Service of Vietnam in Hanoi on 06 September
2000).
From early September 2000, due to rains and medium rain on the midstream and upstream of the Mekong River Delta, the flood water levels at gauging stations on the Mekong River rose rapidly. At 07:00 on 05 September 2000, the flood water level at the Luang Phra bang was at 16.94 m; the flood water level at the Vien Chan gauging station was at 10.34 m; the flood water level at the Kra chie gauging station was at 22.37 m. These flood water levels are higher than the peak levels occurred in mid July 2000.
Due to effects of the upstream large flooding, the flood water levels at upstream gauging stations were at high levels and rising rapidly with the average intensity of 4 to 6 cm per day.
At 07:00 on 06 September 2000, the flood water level on the Tien River at the Tan Chau gauging station was at 4.53 m (0.33 m above Alarm Level III and approximate the peak level in 1994); the flood water level on the Hau River at the Chau Doc gauging station was at 4.15 m (0.65 m above Alarm Level III). These levels are about 0.3 m higher than the peak level in early August 2000. The flood water levels at the Dong Thap Muoi and Tu Giac Long Xuyen gauging stations ate at high levels. The flood water level at the Moc Hoa gauging station was at 2.02 m (0.22 m above Alarm Level III); that at the Tri Ton gauging station was at 2.37 m and continued to increase.
FORECAST:
In the next five days, the upstream flood water levels in the Mekong River Delta will continue to rise. On 11 September 2000, the flood water level at the Tan Chau gauging station will likely be at 4.70 m (0.50 m above Alarm Level III); the flood water level at the Chau Doc gauging station will rise to 4.40 m (0.90 m above Alarm Level III). The flood water levels will remain at the peak levels as in 1978 and 1984 and continue to rise.
By 10 September 2000, due to effects of upstream flood water together with spring tides, the inundation situation in Dong Thap Muoi and Tu Giac Long Xuyen areas will be more severe. The flood water levels on rivers, irrigation ditches, and interior field areas will rise to very high levels.
It is essential to take active measures in response to large floods, the same as those in 1978 and 1996, in the Mekong River Delta.
Distinction of river flood alarm levels:
Alarm Level I Possible flood condition - River water level is high; threat to low height embankments; flooding of very low lying areas; infrastructure safe.
Alarm Level II Dangerous flood condition - Flood plane inundation expected; towns and cities still generally protected by flood defences; high velocity River flows pose danger of bank and dyke erosion; bridge foundations at risk from scour; infrastructure generally safe.
Alarm Level III Very dangerous flood condition - All low lying areas submerged, including low lying areas in cities and towns; safety of River protection dykes in jeopardy; damage to infrastructure begins.
Alarm Level III + Emergency flood condition - General and wide spread uncontrollable flooding; dyke failure a certainty and probably uncontrollable; damage to infrastructure severe.