Abstract:
According to BMA MAster Plan 1992, block building are not allowed to construct in the area declared as 'green zone". However, land development during the lats five years in western and eastern side of BMA influence land use change from agricultural to residential uses. Therefore, in 1998 the Master Plan has amended and lead to permission of commercial building in green zone. The study aims to investigate environmental impact of the change from green area to be commeraicl buildings, especially affected by building so called townhouse and commercial building. Approach of the study follows the Office of Environment Policy and Planning's guideline for impact study. The building selected for the study includes single houses, twin house, town house, block and residential building, dormitory and condomunium. The result shows that impact on drainage system come from town house, block and residential buildings and dormitory. It can be expalined that the buildings have altered previous surface land from agriculture to paved surface. It is directly impact on reducing watershed area and drainage system. Thus the study refer to runoff coefficient to clarify the impact. The study has suggested the mitigative measure by introduce water storage area for delaying the water to the drainage system to the new development estate at lease three percent of total area. This measure is also corresponding to Kam Ling King's Project. In addition, to reserve agriclutural area in the green zone, land tax reducing for compensation different value of land shhould be considered.