Modeling river water quality to assess standard compliance with restricted data: Case study of the Cau River watershed
The degradation of water quality in watersheds is mainly due to socio-economic development, including population growth, urbanization, industrialization and intensification of agriculture. Integrated watershed resources management (IWRM) can be applied to limit this negative impact. The GIBSI model is a tool that can be used to apply IWRM. It includes a sub-model for nitrogen and phosphorus production and transport (PO), and a sub-model for river water quality (Qual-GIBSI). This study focuses mainly on the applicability of these two sub-models in a tropical zone with a monsoon-type climate in a context of restricted data. This exercise will, among other things, validate whether these sub-models are applicable under these conditions. The application will also verify to what extent the river water quality standards are met. The Cau River watershed in Vietnam is used as a case study. We demonstrated through this study that even in this monsoon tropical catchment area where available data are limited in quantity and quality, the PO and Qual-GIBSI models can provide useful information for managing water quality.