The Ha Thanh River (Binh Dinh Province-Central Vietnam) is poorly known. With a basin of
620 km2
this fluvial system is very short (58 km) between the upper basins and delta floodplain (supplying
the Thi Nai lagoon). This basin is concerned with a typhoon season (October–November). The Ministry of
Natural Resources and Environment of Viet Nam (2009) reported that this delta will be affected by
environmental changes by 2100: hydro-level rise the sea in central Viet Nam; increased frequency and
intensity of rainfall. In parallel, the urban projects in the Ha Thanh Basin could make human societies more
vulnerable to hydrological risks. This paper presents the main concepts of the environmental assessment of
the catchment using hydrological modelling and GIS. The entire process is carried out in a Geographic
Information System, which could become a tool for the management and monitoring of the hydrology in Ha
Thanh Basin.