Assessment of Loading Capacity for Watershed Management of Organic and Nutrient Pollutant Load in Vietnam with Water Quality Simulation Model

摘要

Many large rivers in Vietnam are facing challenging problem of deterioration of water quality. Discharge of organic pollutants, such as COD, BOD, and nutrient pollutants, such as total nitrogen and total phosphorus is increasing in parallel with economic growth rate. This situation has brought a real challenge in protection of river water quality, and watershed management. The first step is to study current loading capacity of pollution-risk-rivers in Vietnam. The second step, based on assessment results, is to propose effective countermeasures for improving water quality. The third step is to discuss among stakeholders and to reach an agreement in a river basin to meet its desirable pollution load outcome. The study in loading capacity assessment, therefore, provides an effective tool for watershed management in general, and Vietnam in particular. Our study indicates a procedure for loading capacity assessment, including data collection, from pollutant discharge sources, and hydrological and meteorological observation data, construction of a water quality simulation model by SWAT, and assessment of loading capacity at a control point in the upstream of Cau river. This work was sponsored under a JICA Project for Strengthening Capacity of Water Environmental Management in River Basin in Vietnam.