Application of Regional Nutrient Management Model in Tunxi Catchment: In Support of the Trans-boundary Eco-compensation in Eastern China

The first trans-provincial watershed eco-compensation pilot project has been implemented in Xin'anjiang River watershed, standing between China's Anhui Province and Zhejiang Province. The project purpose is to solve the trans-boundary pollution issue, while ensuring sustainable use of water resources. Models have been proved to be effective tools for identifying major environmental objectives, especially in regard to the watershed management of agricultural non-point source pollution. The regional nutrient management (ReNuMa) model was employed to interpret the main environmental problem (nitrogen contamination) generated within Tunxi catchment, the headstream of Xin'anjiang River watershed. After collecting and processing the available data and parameters, ReNuMa simulated stream flow, sediment yields and dissolved nitrogen loads on a monthly scale from 2000 to 2010 and thus estimated total nitrogen loads. Sensitivity and scenarios analysis were done to infer effective management options. The results showed that source apportionments of N loads emphasized the contribution proportion of each pollution source and characterized the temporal variations caused by natural and anthropogenic factors. Effective countermeasures were elicited by a series of scenarios analysis for water quality improvement. The application of the ReNuMa model showed usefulness to plan N management strategy for policy makers, which in turn helped reduce the N loads draining to the downstream, and gained mutual benefits from the ongoing trans-provincial watershed eco-compensation pilot project.