(introduction...)

The key of the maps enclosed (figures 34 to 37) is based on them.

2.1. Deltas

The deltas are characterised by very high population densities and major cities, quite often capitals, and are associated with intensive rice-growing. This does not exclude, for reasons mentioned above, the existence of rapidly developing pioneer fronts close to the coastal lines. The dominant ethnic groups make the majority in the deltas. Yet we can find there pockets of minorities: foreigners in the cities, if not people who represent the remainder of a late assimilation of the deltas in the centre of the countries. This dense human presence is yet associated to a physical environment which increases the dangers by the conjunction of cyclones, floods, high tides, storm surges and if not, local tsunamis. International openings increase the vulnerability while modifying the previous danger management measures as can be seen by the development of Hanoi that has been faced with an evolutive management of the dykes network.

2.2. Inland basins

The inland basins, too, have high population densities associated with the historical or present (Laos) capital cities and irrigated rice-growing. The majority ethnic group of the countries largely dominates especially in the countryside whereas the minority groups, often Chinese, are found in the urban areas linked to trade. The international opening-up is more restricted though variable depending on the country. The bridge over the Mekong river, that facilitates the links between Vientiane and Thailand, has been, in a quite characteristic way, called the "Friendship bridge". This type of territory is therefore still largely dominated by rural agricultural activity which probably reduces and minimizes the perception of flood risks while droughts are mentally dreaded (RIGG, 1995).

2.3. Coastal plains

With the exception of Vietnam, the minority groups represent there a high percentage of the population. The access to these areas remains limited and often difficult and international investments are limited and selective, for example touristic enclaves and shrimp breeding. On a local level, the presence of commercial cultivation can be more significant like in the South of Thailand where it is associated with a minority Malay community. Although the predominant dangers obviously vary according to the latitude, the coast orientation, and the immediate back country, they are linked to cyclones and floods which can be aggravated by storm surges and high tides.

2.4. Coastal mountains

Directly concerned by cyclones and flash floods, the coastal mountains are still associated with, and named after, the minority ethnic groups living there and who often use their knowledge of the relief to oppose the central power and illegally trade with the neighbouring countries. These minority ethnic groups frequently practice "slash and bum" agriculture. The access to these mountains remains difficult even though the proximity to the coasts has sometimes given rise to the development of commercial cultivation. This is the case in Myanmar with the small rubber plantations "on the well-irrigated sides of the Arakan relief (BRUNEAU, 1995, p. 159).

2.5. Inland mountains

The inland mountains are also occupied by minority ethnic groups. These groups are numerous and poorly controlled by the central powers. The population density is there obviously limited and the mountains are far from being easily accessible. They are only concerned with scarce selective projects liable to open the area especially towards China. The fulfilment of such projects will however depend on the development of international relationships that are often strained in the area. According to ESCAP, the principal advantage of the Mekong Committee lies in "strengthening co-operation, mutual understanding and trust among the riparian countries" (¹⁵). While these mountains are not subject to the most intense cyclones, however they may experience droughts and suffer from flash floods and mass movements, which makes the access still more difficult.

¹⁵ In: ESCAP and the Mekong cooperation. Water Res. Jour., Sept 1997, p. 4.

Key to the maps showing territories prone to risks. (Figs. 34 - 35 - 36 - 37)

Fig. 34 - Territories prone to risks in Bangladesh and Myanmar

Fig. 35 - Territories prone to risks in Thailand

Fig. 36 - Territories prone to risks in Laos, Cambodia and Vietnam

Fig. 37 - Territories prone to risks in the Philippines