Response of runoff and nitrogen loadings to climate and land use changes in the middle Fenhe River basin in Northern China

Abstract

Investigating and understanding the responses of runoff and nitrogen loading to climate and land use change is particularly important for future water resources management. In this article, the Soil and Water Assessment Tool (SWAT) was used to simulate runoff and nitrogen loading in the middle reaches of the Fenhe River. The model was calibrated by the SWAT calibration and uncertainty procedure (SWAT-CUP) to achieve the accuracy of simulating runoff and nitrogen loadings. Furthermore, 20 climate change scenarios and 7 extreme land use change scenarios were set up and run on the calibrated model. The results showed that runoff and nitrogen loading decreased when temperature increased and increased with increasing precipitation. Runoff was more sensitive to changes in precipitation (±10%) than temperature (±2 °C), while nitrogen loading showed the opposite pattern. When the two climatic factors changed in the same direction, the combined effect was larger than either factor alone, whereas the change in the opposite direction produced a weaker effect. The changes produced by different extreme land use scenarios on runoff and nitrogen loading were significantly different and were more obvious during the flood season than in the non-flood season. The results of this study provide a useful guide for water resource managers.

Effect of river damming on nutrient transport and transformation and its countermeasures

“…According to Harrison et al, in the mid-1990s, global reservoirs eliminated 464 Gmol N annually (Harrison et al, 2009;Harrison et al, 2010;Van Cappellen and Maavara, 2016). Denitrification, the major nitrogen removal mechanism in reservoirs, contributes to approximately 58-59% of the total removal (Zhu et al, 2022).…”

Difference in the Contribution of Driving Factors to Nitrogen Loss With Surface Runoff Between the Hill and Plain Agricultural Watersheds

“…Agricultural land generally produces the largest N load, followed by tea plantations, citrus groves and woodlands (Zhang, Li, et al., 2020). Although urban land accounts for a small proportion in agricultural watersheds, it increases the proportion of impervious surface, reduces land permeability, leads to higher runoff amount and non‐point source N load especially during rainy seasons (Alamdari et al., 2022; Vystavna et al., 2023; Zhu et al., 2022). N fertilization can increase crop yield, but cannot be fully absorbed by crops, and then partially enter rivers and lakes through runoff or seepage.…”

Trend Analysis of Climatic Parameters Using Geographical Information Systems: A Case Study of Sivas Province (1982-2021)

“…Studies have shown that climate change is influencing the water cycle, leading to shifts in low, mean, and high streamflow (Gudmundsson et al, 2021). These changes in temperature and precipitation have long-term effects on water resources, with climate change intensifying in the coming decades (Zhu et al, 2022). The global mean surface temperature is estimated to have increased by 0.74°C ± 0.18°C from 1906 to 2005, nearly twice as much warming in the past 50 years as in the past 100 years (Trenberth et al, 2007).…”