Simulating the impact of flooding events on non-point source pollution and the effects of filter strips in an intensive agricultural watershed in China

Abstract

Non-point source pollution (NPSP) has become a critical pollution source after many improvements in point source pollution treatment have been made, particularly in China, due to intensive agricultural activities. Moreover, the impact of NPSP on surface water quality is significantly affected by extreme events, such as flooding. In this study, the soil and water assessment tool model was used to characterize the behaviours of NPSPs and to evaluate the effect of filter strips during flooding periods. The results showed that a flooding event in 2002 caused by a long duration of rainfall (event_1) contributed approximately 40 % of the annual sediment and organic N yield and 18.4 % of nitrate N yield. In 2007, more than 50 % of the annual sediment and organic N and 20 % of nitrate N export were caused by a flooding event due to heavy rainfall (event_2). The simulation results highlighted the severe threat of flooding events on aquatic environments. Furthermore, filter strips of different widths were simulated in these flooding scenarios to test their mitigation effects on the deterioration of surface water quality during these two events, and the 10-m filter strip did decrease more than 30-40 % of the loads of all NPSPs. Our study stresses that more attention should be paid to assessing the impact of flooding events on water quality management measures and pollution loads, as well as the effect of management practices on both aquatic and terrestrial ecosystems to develop sustainable water and soil resources.

Effect of Climatic Factors on Stem Biomass and Carbon Stock of Larix gmelinii and Betula platyphylla in Daxing’anling Mountain of Inner Mongolia, China

“…In addition, a high quantity of rainfall and humidity can cause loss of nutrients overflowing [62]. For more accurate precision of tree biomass prediction, incorporating different stand levels of the tree and climate variables could be better [63,64].…”

Spatiotemporal features of pollutant loads in the Yan River Basin, a typical loess hilly and gully watershed in the Chinese Loess Plateau

“…The spatial analysis indicated that the impact of the high-intensive rainfall on the downstream (from Ganguyi to Tanjiahe) was great due to the confluence of the river tributaries in 2013, suggesting the severe threat of flooding events to the aquatic environment. It has been recognized that pollutant fluxes were very large during an extreme year because the pollutants temporarily stored in channels or slope lands are quickly entrained and transferred during floods (Chen et al 2015b). For example, the average value of COD was 155,683 kg/day at Ganguyi during 2013, which is nearly 9 times the average load (18,211 kg/day) across other years.…”

Spatiotemporal Features of Pollutant Loads in the Yan River Basin, a Typical Loess hilly and Gully Watershed in the Chinese Loess Plateau

“…The spatial analysis indicated that the impact of the high-intensive rainfall on the downstream (from Ganguyi to Tanjiahe) was great due to the confluence of the river tributaries in 2013, suggesting the severe threat of flooding events to the aquatic environment. It has been recognized that pollutant fluxes were very large during an extreme year because the pollutants temporarily stored in channels or slope lands are quickly entrained and transferred during floods (Chen et al, 2015b). For example, the average value of COD was 155,683 kg/d at Ganguyi during 2013, which is nearly 9 times the average load (18,211 kg/d) across other years.…”