Joint Research(Type Ⅳ）
Long-term Channel Evolution and Settlements Location in Response to the
Flood Disaster in the Red River Delta Plain
Project Leader: FUNABIKI, Ayako, College of Humanities and Sciences, Nihon
University
（Term：2011 - 2012）
- Joint Seminars in 2011 Fiscal Year
- Outline of Joint Research
- This project aims to clarify the impact of the long-term environmental
changes, such as flood events and channel evolution, on the settlements
located on the Song Hong (Red River) Delta, northern Vietnam. Using paleo-topographic
maps, radiocarbon dating and sediment environment analysis of new drilling
cores from Duong River basin, we will clarify the flood frequency in recorded
history. Then, comparing them with settlement locations from historical
records, we will examine how the people adapted to long-term environmental
change.
- Purpose of Joint Research
-
Massive disasters that occur only once in 1,000 years like the Great East
Japan Earthquake, are hard to predict. From a geomorphologic viewpoint,
it is important to investigate past tsunami, storm surges, or flood sediments
to estimate the scale and period of the disasters in order topredict future
disasters.
The Song Hong delta, northern Vietnam is vulnerable to river flooding.
Dynasties tried to control floods by repeatedly constructing artificial
dykes. Near Hanoi City, two distributaries, named Day River and Duong River,
diverge from Song Hong. These two distributaries played important roles
in transport and physical distribution. Although the Day river was cut
from the main Song Hong by a movable dam during the French colonial era,
the Duong River flows through 20% of the whole Song Hong discharge. The
Duong River is known as a fast-flowing river, and also called the “Canal
des Rapides”. Because of high sediment discharge, the Duong River was once
obstructed at the divergence point with the main Song Hong in 19th Century.
In previous studies, no high-resolution borehole investigation has been
carried out in the Duong River basin. The timing of its diversion from
the main Song Hong, characteristic of the sediments and flood frequency
were poorly studied. In this project, using paleo topographic maps, radiocarbon
dating and environmental analysis of the new drilling core, we will investigate
the flood frequency and calculate the sediment discharge caused by flooding.
Then, we examine the spatial composition of villages in the historical
documents and archeological records, to clarify how the people adapted
to the environmental changes on a millennium and centennial time scale.
- Outline of Result
- On July 2011, we collected topographic maps of the Red River Delta during the French colonial era in the French National Geographic Institute (IGN France). Geometric correction was done using GIS software, Arc GIS. For the drilling investigation, we had a technical meeting with Dr. Luan and his colleagues in the Hanoi University of the Mining and Geology.
In the next fiscal year, we will investigate the flood frequency and calculate the sediment discharge by floods, using radiocarbon dating and environmental analysis. Then, we examine the spatial composition of village in the historical documents and archeological records, to clarify how the people adapted to the environmental change in millennium and centennial time scale.
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