The Challenges of Planning for Integrated Catchment Management and Stormwater Source Control for Environmental Improvement in Bangkok

Abstract

This research aims to develop planning policy framework and appropriate guidelines to mitigate stormwater contamination in floodplain cities, using Bangkok as a case study. The application of Integrated Catchment Management (ICM) and stormwater Source Control (SC) approaches through integrated planning approaches including institutional and legal frameworks, water resource management, and land-use planning may potentially contribute to the environmental quality improvement in floodplain cities. ICM takes into account the interactions between land, water and other natural resources in a catchment (Ashton, 2000). Stormwater SC strategies recognise holistic and long-term methods to provide a sustainable stormwater management measure (EPA, 2013). These methods use functions of natural features to minimise stormwater generation and contamination. The growth of anthropogenic land-use change has resulted in the conversion of natural areas into impervious surfaces and caused negative impacts on river water quality in many floodplain cities. Traditional stormwater management approaches often direct runoff to impair streams and rivers. Untreated stormwater runoff remaining in the catchment has caused the impairment of downstream areas, resulting in the degradation of ecosystem function. In Thailand, the ongoing urbanisation associated with the increasing portion of impervious surfaces has contributed to water pollution throughout the lower Chao Phraya River and Bangkok area. This river is considered to be one of the most degraded rivers in the country, mostly contaminated by domestic, agricultural and industrial wastewater from surrounding land use (Greenpeace International, 2011). Although the concept of ICM has shaped a number of national policies in Thailand, the insufficiency of planning processes, institutional arrangements, and the legal framework make implementation very difficult to achieve. As ecological and environmental issues have become more complex, sustainable solutions such as ICM and SC approaches need to be incorporated to deal with the inherent complexity of catchment management issues. This research identified the barriers of catchment management planning by addressing a holistic approach within ICM frameworks. The potential for applying SC approaches within the Chao Phraya River Basin was identified to demonstrate the mitigation measures to stormwater contamination. Finally, the results were discussed to provide a planning framework for the remediation of environmental issues in order to contribute to urban sustainability.