WNF-NutriShed
WNF-NutriShed
Authors
Yongqiu Xia and Xiaoyuan Yan (State Key Laboratory of Soil and Sustainable Agriculture, Changshu National Agro-Ecosystem Observation and Research Station, Institute of Soil Science, Chinese Academy of Sciences, China)
Contact yqxia@issas.ac.cn
Website
Description
WNF-NutriShed (The Water Network-based model Framework for Nutrient in waterShed) is a network-based predictive framework of the nutrient transport process in nested water bodies, which incorporates topology structure, hydrological and biogeochemical processes, and connectivity to perform a nonlinear and distributed scaling of nutrient transfer and retention. The framework was validated and applied to N transport in several small multi-water continuum watersheds and ten large basins in China. We assume that released nutrients flow downhill from the cropland, through overland runoff or ditches and ponds, and probably again through ditches and ponds, and then enter a stream network, finally reaching a reservoir or lake. In a nested water bodies continuum, a watershed could be divided into w sub-watersheds according to w water bodies (Fig. 1). We use a subscript w for each source to identify the sequence of the water body and its associated sub-watershed according to its position and pathway. The subscript “w” is designed to reflect the routing of a source and forms the basis of important hydrographical indicators of its topological structure.
Fig.1 Conceptual structure of WNF-NutriShed: Spatially explicit nutrient loading from cropland to watershed outlet through ditch, pond, stream, and reservoir waterways.
Based on the spatio-temporal characteristics of nutrient transfer and retention, we distinguish two kinds of waterways: isolated areal water bodies (AW) and interconnected linear water bodies (LW). Isolated areal water bodies located away from rivers, such as ponds, reservoirs, lakes, and wetlands, are connected episodically or only via the subsurface. The final quantity of the nutrient load depends on the residence time and retention efficiency of LW and AW through which the nutrients pass. Residence time in AW depends mainly on water area and depth. Interconnected linear water bodies are ditches, streams, and river networks, sometimes connected with reservoirs and lakes, where residence time depends mainly on the length and the slope. Nutrient retention efficiency for AW is significantly different from that of LW because of their small size with high perimeter length per unit area, low flow velocity, and the first landscape flush of solutes. The value of differentiating these two water bodies is to better represent nutrient retention by simple geometric and geographic parameters.
Fig.2 Model platform which embed in ArcGIS, packed in toolbox, modeled in requirement
Fig.3 Example modeling: Spatially explicit nitrogen (N) loading from cropland to watershed outlet through ditch, pond, stream, and reservoir waterways in the Jurong reservoir watershed.
Scientific articles
Xia Y Q, Yan X Y. How Variations in Constructed Wetlands Geography Affect Nutrient Discharge. Journal of Geophysical Research: Biogeosciences, 2020, 125 (2): e2019JG005610.
Xia Y Q, Zhao D, Yan X Y, et al. A new framework to model the distributed transfer and retention of nutrients by incorporating topology structure of small water bodies. Water Research, 2023, 238: 119991.
Deng O, Wang S, Ran J, et al. Managing urban development could halve nitrogen pollution in China. Nature Communications. 2024, 15 (1): 401.
Deng O, Huang S, Wang C, et al. Atmospheric Nitrogen pollution control benefits the coastal environment. Environmental Science & Technology. 2024, 58(1): 449-458.
Technical information
Operating system(s): Windows
Language: Python
Output(s): geoTiff file
