Assessment of Water Quality Problems and Mitigation Potential by Using Material Flow Analysis – a Case Study in the Thachin River

Material flow analysis (MFA) is a promising tool for river water quality management. Based on orders-ofmagnitude estimations, the approach provides an overview of pollution problems and their dimensions in a river system, allowing to identify key sources and pathways of pollution, and to evaluate mitigation priorities. The current study aims at investigating MFA to assess river water quality problems and mitigation measures in developing countries, based on a case-study carried out in the Tha Chin River Basin (TRB), Thailand. The TRB is an intensively used river basin, with large variety and spatial heterogeneity of pollution generating activities in a complex hydrological system. A key difficulty is the scarce database. To tackle these challenges, specific complements are integrated with the basic MFA framework. In an up-/downscaling approach, MFA is conducted on different spatial levels, thereby allowing to finally formulate scenarios on any required level of detail. A parallel stakeholder involvement process aims to adequately engage stakeholders in designing and selecting the MFA-based scenarios. The significance of MFA in the context of transboundary river management lies in its' transparency, coupled with the capability of system understanding. MFA is an ideal communication platform to directly involve stakeholders of different levels in participatory planning and decision-making. Condensed into a visualized, comprehensible message, MFA results provide an excellent technical basis to understand up/downstream connections, and to facilitate discussion on regional cooperation among riparian countries.