Abstract
Water Management System Suitable to the Tropical Monsoon Climate
Hue was the capital of the Nguyen Dynasty and is located in the coastal area north of the Hai Van Pass, which is in the central part of Viet Nam. And it belongs to the tropical monsoon climate, which has a distinctive rainy season and a rather vague dry season climatically.
At the centre of the imperial tombs of the Nguyen Dynasty, reservoirs were constructed to suit conditions of the tropical monsoon climate, and these were designed and maintained so that the water level of the lakes would not change largely all through the year, to prevent flooding from damaging those tombs and those downstream areas during the rainy season, while in the dry season the lakes were supposed not to dry up and to supply irrigation water to the downstream areas.
However, at present, around those imperial tombs, including the Gia Long Tomb, it seems that the water management system developed to meet the specific conditions of the region’s climate is not functioning as necessarily. So we would like to point out about each of the issues and make proposals about how to restore the traditional water management system in the future.
2. Breakage of Traditional Water Management Facilities and Changes in Land Use in the Gia Long Tomb Area
Some important water management facilities both upstream and downstream of the lake are deteriorated and currently these facilities do not look like they are functioning as originally planned. And, the amount of mud flowing into the lake has been increasing around the lake and upstream areas as the forests in the neighbourhood are increasingly becoming those of acacia trees. In addition to this, if the lake is not maintained appropriately, for example, if any deteriorated lakeside embankment is not repaired and sludge accumulated at the bottom of the lake is not regularly dredged away, the lake bottom becomes shallower and shallower and it will reduce the capacity to store water in the lake.
3. For Restoration of the Traditional Water Management System
We would like to make three proposals for restoration of the traditional water management system that has existed in this region. First of all, repair of important water management facilities. These are a key element to support the traditional water management system. For example, in the Gia Long Tomb, it is an urgent issue to repair the stone covered waterway and the water gate that control the water level of the lake. Secondly, we would propose reconsideration and review of forestry focusing on acacia trees around imperial tombs and upstream areas. The third proposal is about repair of the embankment to prevent soil draining in the lake and regular dredging of the lake.
