An integrated simulation-monitoring framework for nitrogen assessment: a case study in the Baixi watershed, China

作者:Chen L; Liu R M*; Huang Q; Chen Y X; Gao S H; Sun C C; Shen Z Y; Ou S Z; Chen S L
来源:18th Biennial ISEM Conference on Ecological Modelling for Global Change and Coupled Human and Natural Systems, 2011-09-20 to 2011-09-23.
DOI:10.1016/j.proenv.2012.01.101

摘要

As the deterioration of drinking water quality has become increasingly severe worldwide, there is a considerable need to accurately identify variable pollution sources. Currently, simulation programs have been shown to be less effective in short-term and detailed simulations. Therefore, this study advanced an integrated framework for simulation by combining the modelling and monitoring methods. A case study was conducted to identify the spatial and temporal distribution of nitrogen (N) in the upstream watershed of a typical drinking water reservoir, in the city of Ningbo, Zhejiang province, China. In this study, a watershed model, Soil and Water Assessment Tool (SWAT), was used to estimate N load for the 254 km(2) upper stream watershed; while storm runoff samples were also collected to illuminate more detailed processes in the storm event. Based on the model output, the critical N source in Baixi watershed was identified as the forest. The potential nonpoint source (NPS) pollution risk areas were also illustrated as Sub-basin 21, 20 and 26. In addition, the model simulation proved that the Qingshui River contributed more N load than the other two tributaries. Conversely, the short-term and detailed trends were obtained through storm sampling. By analyzing the storm samples, it was clear that the N load into the drinking water reservoir results from a combination of land-use, agricultural activities, as well as atmospheric deposition, especially in the acid rain control region. It could be further inferred that modelling and monitoring could serve as a framework to provide information for N load prediction and protection of drinking water. Using the integrated simulation-monitoring framework, the SWAT model could be used as an effective tool to foretell the potential risk of detrimental NPS conditions, while monitoring could provide an inventory and detailed means to further study short-term trends.

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